JP2005194666A

JP2005194666A - Water-soluble polyvinyl alcohol-based fiber

Info

Publication number: JP2005194666A
Application number: JP2004002680A
Authority: JP
Inventors: Riyoukei Endou; 了慶遠藤; Tetsuya Hara; 哲也原; Tomoyuki Sano; 友之佐野; Akio Omori; 昭夫大森; Naoki Fujiwara; 直樹藤原
Original assignee: Kuraray Co Ltd
Current assignee: Kuraray Co Ltd
Priority date: 2004-01-08
Filing date: 2004-01-08
Publication date: 2005-07-21

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-soluble PVA-based fiber having fiber performances such as practically sufficient mechanical properties and chemical resistance without impairing a conventional water-soluble property and extremely useful for nonwoven fabrics including a base fabric for chemical lace and many applications including spun yarn and to provide a method for producing the fiber. <P>SOLUTION: In the water-soluble PVA-based fiber, a compound having an ionic group is reacted in a ratio of 0.01-5 mol% and the relationship between a degree (Xc/%) of crystallization of the fiber and a water-fusing temperature (Wtb/°C) of the fiber satisfies the formula: Wtb<2.50×Xc-70, wherein 30%≤Xc≤80%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、従来の水溶性を損なうことなく、実用上十分な機械的特性、耐薬品性などの繊維性能を兼ね備えた水溶性ポリビニルアルコール（以下、ＰＶＡと略記する）系繊維に関するものであり、ケミカルレース用基布をはじめとする不織布や紡績糸をはじめとして多くの用途に極めて有効に使用することができる。 The present invention relates to a water-soluble polyvinyl alcohol (hereinafter abbreviated as PVA) fiber having fiber performance such as practically sufficient mechanical properties and chemical resistance without impairing conventional water solubility, It can be used very effectively in many applications including non-woven fabrics and spun yarns, including chemical lace base fabrics.

従来、水に溶解する繊維としては、ＰＶＡ系繊維、カルボキシメチルセルロースなどのセルロース系繊維、ポリアルギン酸系繊維、ポリアルキレン系繊維などが知られているが、カードやニードルパンチなどの不織布化工程及び紡績などの織布化、あるいはニット化工程を安定に通過するに必要な機械的特性や耐薬品性に優れているものはＰＶＡ系繊維のみである。また近年地球環境保護、消費者保護が強く望まれているが、ＰＶＡ系ポリマーは自然環境の中で生分解することが明らかにされており、環境保護の観点から水溶性ＰＶＡ系繊維は、最適な繊維として期待されている。 Conventionally, PVA fibers, cellulose fibers such as carboxymethyl cellulose, polyalginic acid fibers, polyalkylene fibers, and the like are known as fibers that dissolve in water. Only the PVA fibers are excellent in mechanical properties and chemical resistance necessary for stably passing through the woven or knit process. In recent years, protection of the global environment and consumers has been strongly desired, but it has been clarified that PVA polymers are biodegradable in the natural environment. From the viewpoint of environmental protection, water-soluble PVA fibers are optimal. It is expected as a new fiber.

水溶性ＰＶＡ系繊維の製造方法として、例えば平均重合度２００〜５００という低重合度ＰＶＡ系ポリマーを使用して水溶解性を向上させることが提案されており、具体的には５℃以下の水に速やかに溶解することが開示されている（例えば、特許文献１参照。）。しかしながら、重合度が低いＰＶＡ系ポリマーを用いるため繊維の結晶化度を高めることができず、それ故繊維の機械的特性は低いものとなり、実用上の使用に制約がかかるものであった。更に、該繊維にはホウ酸あるいはホウ酸塩を含んでおり、該水溶性繊維を溶解除去するのに使用した廃水中にはホウ酸が多く含まれることとなり、それを処理するための特別な処理方法及び装置が必要となるなどの問題を抱えていた。 As a method for producing water-soluble PVA fibers, it has been proposed to improve water solubility by using a low polymerization degree PVA polymer having an average degree of polymerization of 200 to 500, for example, water at 5 ° C. or less. (See, for example, Patent Document 1). However, since the PVA polymer having a low degree of polymerization is used, the crystallinity of the fiber cannot be increased. Therefore, the mechanical properties of the fiber are low, and the practical use is restricted. Further, the fiber contains boric acid or borate, and the waste water used for dissolving and removing the water-soluble fiber contains a large amount of boric acid. There were problems such as the need for a processing method and apparatus.

一方、ケン化度の低いＰＶＡ系ポリマーの水溶液を芒硝などの塩類の濃厚水溶液中に湿式紡糸し、次いで低い延伸倍率で延伸することにより５０℃以下で溶解するＰＶＡ系繊維を得る方法が記載されている（例えば、特許文献２参照。）。また、ケン化度の低いＰＶＡ系ポリマーを用いて乾湿式紡糸し、次いで低い延伸倍率で延伸することで低温溶解可能なＰＶＡ系繊維が提案されている（例えば、特許文献３参照。）。さらにはケン化度の低いＰＶＡ系ポリマーを用いてジメチルスルホキシド（以下、ＤＭＳＯと略記する）などの有機溶媒に溶解した溶液をメタノールなどの固化能を有する固化浴に紡糸することにより低温水溶解可能なＰＶＡ系繊維が提案されている（例えば、特許文献４参照。）。これらの方法はいずれもケン化度の低いＰＶＡ系ポリマーを用いることによって初めて達成できるものであり、低温水溶解性を付与する観点では極めて有用であるが、ケン化度の低いＰＶＡ系ポリマーは、ポリマー自体の結晶性が低く、そのため得られる繊維の結晶性は低いものとなり、実用上必要な機械的特性を兼備することは困難であった。また凝固や抽出などの工程中で一部溶出して繊維間の膠着を引き起こすことなどの問題を抱えており、工程通過性の面で必ずしも満足のいくものではなく、一層の改善が望まれていた。 On the other hand, a method for obtaining a PVA fiber that dissolves at 50 ° C. or lower by wet-spinning an aqueous solution of a PVA polymer having a low saponification degree into a concentrated aqueous solution of salts such as mirabilite and then drawing at a low draw ratio is described. (For example, refer to Patent Document 2). Further, PVA fibers that can be melted at low temperature by dry-wet spinning using a PVA polymer having a low saponification degree and then stretching at a low draw ratio have been proposed (for example, see Patent Document 3). Furthermore, it is possible to dissolve in low-temperature water by spinning a solution dissolved in an organic solvent such as dimethyl sulfoxide (hereinafter abbreviated as DMSO) using a PVA polymer having a low saponification degree into a solidification bath having a solidification ability such as methanol. PVA-based fibers have been proposed (see, for example, Patent Document 4). Any of these methods can be achieved for the first time by using a PVA polymer having a low saponification degree, and is extremely useful in terms of imparting low-temperature water solubility, but a PVA polymer having a low saponification degree is Since the polymer itself has low crystallinity, the resulting fiber has low crystallinity, and it is difficult to combine practically necessary mechanical properties. In addition, it has problems such as coagulation and extraction, partly eluting and causing agglutination between fibers, which is not always satisfactory in terms of process passability, and further improvement is desired. It was.

一方で、高ケン化度、高重合度のＰＶＡ系ポリマーを使用した場合、繊維の結晶化度が高められるため、引張強度などの機械的特性は十分なものとなるが、水溶解温度は１００℃以上となり、低温での水溶解性が損なわれる。このようなＰＶＡ系ポリマーを用いての水溶解性の向上方法としては、例えば延伸温度や延伸倍率を極端に下げることにより、配向結晶化を故意に阻害させることが行われているが、この方法では当然ながら結晶化度が低くなり機械的特性が損なわれてしまうという問題点があった。 On the other hand, when a PVA polymer having a high degree of saponification and a high degree of polymerization is used, the fiber crystallinity is increased, so that mechanical properties such as tensile strength are sufficient, but the water dissolution temperature is 100. It becomes higher than ℃ and water solubility at low temperature is impaired. As a method for improving the water solubility using such a PVA polymer, for example, the orientation crystallization is intentionally inhibited by extremely reducing the stretching temperature or the stretching ratio. Naturally, however, there is a problem that the crystallinity is lowered and the mechanical properties are impaired.

また例えば、高ケン化度、高重合度のＰＶＡ系ポリマーを用いて繊維化の際に、原液溶媒にＰＶＡ系ポリマーの分子中に存在する水酸基と反応し得る原子団を分子内に有する変性剤を同時に添加して、水溶解性をはじめとする様々な特性を付与したＰＶＡ系繊維が提案されている（例えば、特許文献５参照。）。しかしながら、特許文献５に記載の方法では、原液段階での過度の反応による繊維の結晶性低下が起こり、水溶解性はもとより、引張強度などの機械的特性も低い繊維しか得られなかった。また、未反応物質が回収系に混入してしまい、それを処理するための特別な処理方法及び工程が必要となるなどの問題を抱えていた。 In addition, for example, a denaturant having an atomic group in the molecule capable of reacting with a hydroxyl group present in the molecule of the PVA polymer in the stock solution solvent during fiberization using a PVA polymer having a high saponification degree and a high degree of polymerization. Has been proposed at the same time to provide various properties including water solubility (see, for example, Patent Document 5). However, in the method described in Patent Document 5, the crystallinity of the fiber is reduced due to an excessive reaction at the stock solution stage, and only fibers having low mechanical properties such as tensile strength as well as water solubility can be obtained. In addition, the unreacted substance is mixed in the recovery system, and there is a problem that a special processing method and process for processing it are necessary.

特開平３−１９９４０８号公報Japanese Patent Laid-Open No. 3-199408 特開昭５３−０４５４２４号公報Japanese Patent Laid-Open No. 53-045424 特開平５−０８６５０３号公報JP-A-5-086503 特開平７−０４２０１９号公報JP-A-7-042019 特開２０００−１３６４３０号公報JP 2000-136430 A

ケミカルレース用基布をはじめとする不織布の分野では、従来必要とされてきた８０℃以上の水で溶解可能な、いわゆる高温溶解タイプに加えて、最近ではその市場ニーズの高度化から４０〜８０℃の水で溶解可能な、いわゆる中温溶解や、室温付近で溶解可能な、いわゆる低温溶解タイプのものが望まれている。例えば、繊細なデザインの刺繍の場合には、打ち込み密度が大きくなり刺繍後の溶脱が難しくなること、また、シルクやアセテートなどの素材を用いた高級な刺繍をする場合には、素材自身の熱安定性が低いことなどの理由から、より低温で溶解できる繊維を用いた不織布の開発が望まれている。一方で不織布に用いる繊維としては、刺繍の際の刺繍針による繊維の切断を防ぐ為にも、引張強度をはじめとする機械的特性に優れた繊維を用いる必要がある。したがって、ケミカルレース等の不織布に用いる繊維には、水溶解特性と機械的特性という相反する物性を兼備することが望まれている。 In the field of non-woven fabrics, including chemical lace base fabrics, in addition to the so-called high-temperature dissolution type that can be dissolved in water of 80 ° C. or higher, which has been required in the past, recently there has been a 40-80 A so-called medium-temperature solution that can be dissolved in water at 0 ° C., or a so-called low-temperature solution type that can be dissolved near room temperature is desired. For example, in the case of embroidery with a delicate design, the driving density increases, and leaching after embroidery becomes difficult. In addition, when performing high-quality embroidery using materials such as silk and acetate, the heat of the material itself Development of a nonwoven fabric using fibers that can be melted at a lower temperature is desired for reasons such as low stability. On the other hand, as the fiber used for the nonwoven fabric, it is necessary to use a fiber having excellent mechanical properties such as tensile strength in order to prevent the fiber from being cut by the embroidery needle during embroidery. Therefore, it is desired that the fibers used for the nonwoven fabric such as chemical lace have opposite physical properties of water solubility and mechanical properties.

先述したように、従来ＰＶＡ系繊維の水溶解性は、用いるＰＶＡ系ポリマーの重合度やケン化度、または延伸条件などを制御して付与できるものであったが、何れの方法も繊維の有する結晶化度が低くなるために、機械的特性が低くなるなどの問題があったり、それ以外にも工程通過性、コストの面でも問題を抱えていた。従って、水溶解特性と引張強度をはじめとする機械的特性を兼備し、且つ工程通過性が良好で安価な水溶性ＰＶＡ系繊維の開発が望まれていた。 As described above, the water solubility of conventional PVA fibers can be imparted by controlling the polymerization degree, saponification degree, or stretching conditions of the PVA polymer to be used. Since the degree of crystallinity is low, there are problems such as low mechanical properties, and there are other problems in terms of process passability and cost. Accordingly, it has been desired to develop a water-soluble PVA-based fiber that has both water-solubility and mechanical properties such as tensile strength, has good process passability, and is inexpensive.

本願発明者等は上記した水溶性ＰＶＡ系繊維を得るべく鋭意検討を重ねた結果、ＰＶＡ系ポリマーに対して特別な工程を必要とせず、通常の紡糸工程中においてイオン性基を有する化合物を繊維に含浸させ、その後の工程で該化合物と繊維を反応させることで、従来の水溶性を損なうことなく、優れた機械的特性を有する結晶性が高い水溶性ＰＶＡ系繊維を安価に製造できることを見出した。 As a result of intensive studies to obtain the above-described water-soluble PVA fibers, the inventors of the present application do not require any special process for the PVA polymer, and the compound having an ionic group in the normal spinning process is used as a fiber. It is found that water-soluble PVA fibers having excellent mechanical properties and high crystallinity can be produced at low cost without impairing the conventional water solubility by impregnating the fiber with the compound and reacting the fiber with the fiber in the subsequent process. It was.

すなわち本発明は、イオン性基を有する化合物が０．０１〜５モル％反応されてなり、繊維の結晶化度（Ｘｃ／％）及び水中溶断温度（Ｗｔｂ／℃）の関係が以下の（１）式を満たすことを特徴とする水溶性ＰＶＡ系繊維である。 That is, in the present invention, 0.01 to 5 mol% of a compound having an ionic group is reacted, and the relationship between the fiber crystallinity (Xc /%) and the fusing temperature in water (Wtb / ° C) is as follows (1 It is a water-soluble PVA fiber characterized by satisfying the formula.

そして本発明はイオン性基を有する化合物がグリオキシル酸またはグリオキシル酸の中和物であることを特徴とする上記の水溶性ＰＶＡ系繊維である。
また本発明は、重合度１０００〜４０００及びケン化度８８モル％以上であるＰＶＡ系ポリマーを有機溶媒に溶解して得た紡糸原液を、該ポリマーに対して固化能を有する有機溶媒を主体とする固化浴に湿式または乾湿式紡糸し、次いでイオン性基を有する化合物が１〜５０ｇ／ｌ溶解された抽出浴を通して繊維中に該化合物を含浸させ、乾燥、延伸、熱処理の何れかの工程で反応して導入させると共に、全工程における全延伸倍率を３倍以上とする上記の水溶性ＰＶＡ系繊維の製造方法に関するものである。 And this invention is said water-soluble PVA type | system | group fiber characterized by the compound which has an ionic group being the neutralized product of glyoxylic acid or glyoxylic acid.
In the present invention, a spinning stock solution obtained by dissolving a PVA polymer having a polymerization degree of 1000 to 4000 and a saponification degree of 88 mol% or more in an organic solvent is mainly composed of an organic solvent having a solidifying ability for the polymer. In the solidification bath, wet or dry-wet spinning, and then impregnate the compound into the fiber through an extraction bath in which 1 to 50 g / l of the compound having an ionic group is dissolved, and in any step of drying, stretching and heat treatment The present invention relates to a method for producing the above-mentioned water-soluble PVA fiber, which is introduced by reaction and the total draw ratio in all steps is 3 times or more.

本発明によれば、従来技術では達成し得なかった、水溶解特性と引張強度をはじめとする機械的特性を兼備した水溶性ＰＶＡ系繊維を提供することが可能である。また本発明の水溶性ＰＶＡ系繊維は、特別な工程を必要とせず、通常の紡糸、延伸工程で達成可能であり、安価に製造することができる。さらに本発明の水溶性ＰＶＡ系繊維の水溶解性に関しては適宜制御可能であるので、ケミカルレース用基布や紡績糸をはじめとして多くの用途に極めて有用である。 ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the water-soluble PVA type | system | group fiber which has mechanical characteristics including the water solubility characteristic and tensile strength which was not able to be achieved by the prior art. In addition, the water-soluble PVA fiber of the present invention does not require any special process, can be achieved by ordinary spinning and drawing processes, and can be manufactured at low cost. Furthermore, since the water solubility of the water-soluble PVA fiber of the present invention can be appropriately controlled, it is extremely useful for many applications including a base fabric for chemical lace and spun yarn.

以下、本発明について具体的に説明する。本発明に用いるＰＶＡ系ポリマーの重合度は、得られる繊維の機械的特性や寸法安定性、水溶解特性等を考慮すると３０℃水溶液の粘度から求めた平均重合度が１０００〜４０００のものが好ましい。平均重合度が４０００を越えたＰＶＡ系ポリマーを用いた場合、機械的特性の点では優れるが、溶解時の収縮が大きいなどの水溶解特性が損なわれる可能性がある。また、平均重合度が１０００よりも低い重合度のＰＶＡ系ポリマーを用いると、得られる繊維の結晶性が低く、そのため機械的特性が不十分なばかりでなく、凝固や抽出などの繊維製造工程中でポリマーの溶出が起こり、繊維間の膠着を引き起こしやすい。より好ましくは１５００〜３５００である。 Hereinafter, the present invention will be specifically described. The degree of polymerization of the PVA polymer used in the present invention is preferably that having an average degree of polymerization of 1000 to 4000 determined from the viscosity of a 30 ° C. aqueous solution in consideration of mechanical properties, dimensional stability, water solubility characteristics, and the like of the resulting fiber. . When a PVA polymer having an average degree of polymerization exceeding 4000 is used, it is excellent in terms of mechanical properties, but water dissolution properties such as large shrinkage during dissolution may be impaired. In addition, when a PVA polymer having an average degree of polymerization lower than 1000 is used, the resulting fiber has low crystallinity, so that not only mechanical properties are insufficient, but also during fiber production processes such as coagulation and extraction. In this case, elution of the polymer occurs, and it is easy to cause sticking between fibers. More preferably, it is 1500-3500.

本発明で用いるＰＶＡ系ポリマーのケン化度は特に限定されるものではないが、得られる繊維の結晶性及び水溶解特性の点から、８８モル％以上であることが好ましい。ＰＶＡ系ポリマーのケン化度が８８モル％よりも低いものを使用した場合、結晶性が極端に低下するので、低温での水溶解性を付与する点では好ましいが、得られる繊維の機械的特性や工程通過性、製造コストなどの面で好ましくない。 The saponification degree of the PVA polymer used in the present invention is not particularly limited, but is preferably 88 mol% or more from the viewpoint of the crystallinity and water solubility of the resulting fiber. When the saponification degree of the PVA polymer is lower than 88 mol%, the crystallinity is extremely lowered, so that it is preferable in terms of imparting water solubility at a low temperature, but the mechanical properties of the resulting fiber It is not preferable in terms of process passability and manufacturing cost.

また本発明の繊維を形成するＰＶＡ系ポリマーは、ビニルアルコールユニットを主成分とするものであれば特に限定されず、本発明の効果を損なわない限り、所望によりエチレン、酢酸ビニル、イタコン酸、ビニルアミン、アクリルアミド、ピバリン酸ビニル、無水マレイン酸、スルホン酸含有ビニル化合物などの構成単位を含有していてもよい。しかしながら、本発明の目的とする繊維を得るためにはビニルアルコール単位が８８モル％のポリマーがより好適に使用される。もちろん本発明の効果を損なわない範囲であれば、目的に応じてポリマー中に酸化防止剤、凍結防止剤、ｐＨ調整剤、隠蔽剤、着色剤、油剤などの添加剤が含まれていてもよい。 In addition, the PVA polymer forming the fiber of the present invention is not particularly limited as long as it has a vinyl alcohol unit as a main component, and ethylene, vinyl acetate, itaconic acid, vinylamine are optionally obtained unless the effects of the present invention are impaired. , Acrylamide, vinyl pivalate, maleic anhydride, sulfonic acid-containing vinyl compounds and the like. However, in order to obtain the target fiber of the present invention, a polymer having 88 mol% of vinyl alcohol units is more preferably used. Of course, as long as the effect of the present invention is not impaired, additives such as an antioxidant, an antifreezing agent, a pH adjusting agent, a concealing agent, a coloring agent, and an oil may be included in the polymer depending on the purpose. .

本発明の水溶性ＰＶＡ系繊維は、原糸の段階でイオン性基を有する化合物を繊維中に含浸させ、その後の工程で該化合物を反応、導入させることにより得られることが重要なポイントである。このようにして得られた本発明の水溶性ＰＶＡ系繊維の水溶解特性は、繊維が溶解する温度によって示され、後述するが、ポリマー種や、イオン性基を有する化合物の種類、ＰＶＡ系ポリマーへの反応度、及びイオン性基の中和度により幅広い温度範囲で制御することが可能である。 It is an important point that the water-soluble PVA fiber of the present invention can be obtained by impregnating a compound having an ionic group in the fiber at the raw yarn stage, and reacting and introducing the compound in the subsequent steps. . The water-soluble characteristics of the water-soluble PVA fiber of the present invention thus obtained are indicated by the temperature at which the fiber dissolves. As will be described later, the polymer type, the type of the compound having an ionic group, and the PVA polymer It is possible to control in a wide temperature range depending on the degree of reactivity to ionic groups and the degree of neutralization of ionic groups.

本発明で使用するイオン性基を有する化合物としては、ＰＶＡ系ポリマー中の水酸基と反応するものであれば特に限定されずアルデヒド類、エポキシ類、カルボン酸類、イソシアネート類、シラノ-ル類等が挙げられる。また、かかるイオン性基としては、カルボン酸やスルホン酸、あるいはこれらの一部または全量の中和物等、特に限定されるものではない。これらの中でもコスト、入手し易さの点で、カルボン酸またはその中和物であることが好ましく、特に、より低温での水溶解性を付与させたい場合には、カルボン酸の金属中和物を有している化合物が好ましい。さらにこの中でもグリオキシル酸またはその金属中和物が繊維への反応性、水溶性制御、機械的特性の観点から特に好適である。 The compound having an ionic group used in the present invention is not particularly limited as long as it reacts with a hydroxyl group in the PVA polymer, and examples thereof include aldehydes, epoxies, carboxylic acids, isocyanates, silanols and the like. It is done. In addition, the ionic group is not particularly limited, such as carboxylic acid or sulfonic acid, or a partially or completely neutralized product thereof. Among these, carboxylic acid or a neutralized product thereof is preferable from the viewpoint of cost and availability, and in particular, when it is desired to impart water solubility at a lower temperature, a metal neutralized product of carboxylic acid. A compound having Among these, glyoxylic acid or a metal neutralized product thereof is particularly preferable from the viewpoints of reactivity to fibers, water solubility control, and mechanical properties.

例えば該化合物としてグリオキシル酸をＰＶＡ系ポリマーに反応させ導入させた場合、ＰＶＡの分子鎖にカルボン酸を導入できることになる。カルボン酸アニオンは立体障害が大きく、カルボン酸アニオン同士がお互いに反発し合うため、分子鎖の網目が広がり、水分をより吸収しやすい状態を形成することが可能となる。その結果、水の吸収速度が速く、したがってより低温での水溶解性に優れるものとなる。このとき、分子鎖に導入させるカルボン酸部位をナトリウム等のイオン化傾向の大きい金属で中和しておけば、より早くカルボン酸アニオンが生成し、水の吸収速度を高めることができ、したがってより低温で水溶解する繊維が得られる。 For example, when glyoxylic acid is introduced as a compound by reacting with a PVA polymer, carboxylic acid can be introduced into the molecular chain of PVA. Since the carboxylic acid anion has a large steric hindrance and the carboxylic acid anions repel each other, the network of molecular chains spreads, and it becomes possible to form a state in which moisture is more easily absorbed. As a result, the water absorption rate is fast, and therefore the water solubility at a lower temperature is excellent. At this time, if the carboxylic acid site to be introduced into the molecular chain is neutralized with a metal having a high ionization tendency such as sodium, a carboxylic acid anion is generated more quickly, and the water absorption rate can be increased. Gives a fiber that dissolves in water.

イオン性基を中和させるための金属種は特に限定されず、ナトリウムやカルシウム、マグネシウム等が挙げられるが、ナトリウム等のイオン化傾向の大きい金属が好ましい。また中和の方法についても特に限定はなく、公知の方法にて可能である。例えば抽出溶媒にカルボン酸基を有する化合物を溶解し、それに水酸化ナトリウム等を加えることでカルボン酸のナトリウムイオンによる中和が可能である。またこの時に加える金属イオンの量により中和度の制御が可能である。 The metal species for neutralizing the ionic group is not particularly limited, and examples thereof include sodium, calcium, magnesium, and the like, but a metal having a large ionization tendency such as sodium is preferable. Moreover, there is no limitation in particular also about the method of neutralization, and it is possible by a well-known method. For example, it is possible to neutralize the carboxylic acid with sodium ions by dissolving a compound having a carboxylic acid group in the extraction solvent and adding sodium hydroxide or the like thereto. The degree of neutralization can be controlled by the amount of metal ions added at this time.

本発明の水溶性ＰＶＡ系繊維において、上記したイオン性基を有する化合物が０．０１〜５モル％反応していることが必要である。本発明の水溶性ＰＶＡ系繊維におけるイオン性基を有する化合物の反応度が０．０１モル％未満の場合、本発明の目的とする水溶性繊維が得られず、また５モル％を越えると繊維の結晶化度が低くなり、そのため得られる繊維の機械的特性が低くなったり、また溶解時に著しい収縮が起こるなどの問題が生じる。好ましくは０．０５〜４モル％であり、より好ましくは０．０８〜３モル％である。なお本発明の水溶性ＰＶＡ系繊維において、イオン性基を有する化合物の反応度は後述する方法で測定される。 In the water-soluble PVA fiber of the present invention, it is necessary that the compound having the ionic group reacts in an amount of 0.01 to 5 mol%. When the reactivity of the compound having an ionic group in the water-soluble PVA fiber of the present invention is less than 0.01 mol%, the water-soluble fiber targeted by the present invention cannot be obtained. As a result, the degree of crystallinity of the resulting fiber becomes low, resulting in poor mechanical properties of the resulting fiber, and significant shrinkage during dissolution. Preferably it is 0.05-4 mol%, More preferably, it is 0.08-3 mol%. In the water-soluble PVA fiber of the present invention, the reactivity of the compound having an ionic group is measured by the method described later.

また本発明の水溶性ＰＶＡ系繊維の大きな特徴は、水溶性繊維であるにもかかわらず、引張強度をはじめとする機械的特性に優れている点にある。すなわち、水中溶断温度（Ｗｔｂ）と繊維の機械的特性を向上させる指標となる結晶化度（Ｘｃ）の関係が下記式（１）で示されることが重要である。 A major feature of the water-soluble PVA fiber of the present invention is that it is excellent in mechanical properties such as tensile strength despite being a water-soluble fiber. That is, it is important that the relationship between the fusing temperature in water (Wtb) and the crystallinity (Xc) that serves as an index for improving the mechanical properties of the fiber is represented by the following formula (1).

従来、水溶性繊維で行われてきた重合度およびケン化度、延伸条件などによる水溶性制御では、繊維の結晶化を犠牲にするものであったため、機械的特性を兼備した水溶性繊維は得られていない。図１は本発明の水溶性ＰＶＡ系繊維と特開平７−４２０１９号公報および特開平７−９０７１４号公報に記載されている水溶性繊維、および現在市販されている水溶性繊維〔ニチビ（株）製「ソルブロン」〕について、それぞれの水中溶断温度と結晶化度の関係を示したものである。「ソルブロン」には銘柄としてＳＳ、ＳＵ、ＳＸ、及びＳＬがあり、これらを白丸で、また特開平７−４２０１９号公報および特開平７−９０７１４号公報に記載されている水溶性繊維を白四角で、そして本発明の水溶性ＰＶＡ系繊維（実施例）を黒丸、比較例を黒四角で示した。図１に示すように、「ソルブロン」あるいは特開平７−４２０１９号公報および特開平７−９０７１４号公報に記載されている水溶性繊維においては、水中溶断温度（Ｗｔｂ）と結晶化度（Ｘｃ）との関係はほぼ一本の直線で示され、その関係式は下記式（２）で表される。 Conventionally, the water solubility control by the degree of polymerization, saponification, and stretching conditions performed with water-soluble fibers sacrifices the crystallization of the fibers, so that water-soluble fibers having both mechanical properties can be obtained. It is not done. FIG. 1 shows water-soluble PVA fibers of the present invention, water-soluble fibers described in JP-A-7-42019 and JP-A-7-90714, and water-soluble fibers currently on the market [Nichibi Corporation] "Solbron" manufactured by the company] shows the relationship between the fusing temperature of each water and the crystallinity. “SOLBRON” includes SS, SU, SX, and SL as brands. These are white circles, and water-soluble fibers described in JP-A-7-42019 and JP-A-7-90714 are white squares. The water-soluble PVA fibers (Examples) of the present invention are indicated by black circles and comparative examples by black squares. As shown in FIG. 1, in the water-soluble fiber described in “SOLBRON” or JP-A-7-42019 and JP-A-7-90714, the fusing temperature in water (Wtb) and the crystallinity (Xc) Is represented by a substantially straight line, and the relational expression is represented by the following expression (2).

詳細は実施例にて説明するが、本発明の水溶性ＰＶＡ系繊維は何れも式（１）の範囲内（図中斜線部）であり、従来の水溶性繊維に比べて結晶化度が高い、すなわち機械的特性に優れた水溶性繊維を得ることができる。ここで、結晶化度が３０％よりも低い場合、得られる繊維の機械的特性は低いものとなり、また結晶化度が８０％を越えると、Ｗｔｂは１２０℃以上となり、いずれも本発明の目的を満足しない。なお、本発明でいう水中溶断温度（Ｗｔｂ）、結晶化度（Ｘｃ）は後述する方法により測定される。 Although details will be described in Examples, the water-soluble PVA fibers of the present invention are all within the range of the formula (1) (shaded portion in the figure), and have a higher degree of crystallinity than conventional water-soluble fibers. That is, water-soluble fibers having excellent mechanical properties can be obtained. Here, when the crystallinity is lower than 30%, the resulting fiber has low mechanical properties, and when the crystallinity exceeds 80%, Wtb is 120 ° C. or higher. Not satisfied. In the present invention, the fusing temperature (Wtb) in water and the crystallinity (Xc) are measured by the methods described later.

何故、本発明の水溶性ＰＶＡ系繊維が水溶性であるにも関らず結晶化度を高くなるかはさだかではないが、本発明者等は以下のように推定している。
イオン性基を有する化合物を繊維中に導入することにより、繊維自身の融点が若干低下するので、該化合物を導入するとしないでは実質的な延伸条件が異なっていると推測される。したがって本発明ではより融点に近い温度で延伸していると推測される。すなわち、本発明では分子運動性がより高い状態で延伸が行われることになり、配向結晶化が促進され、そのため結晶化度の高い繊維が得られるものと推定される。 The reason for this is that the water-soluble PVA fiber of the present invention has a high degree of crystallinity despite being water-soluble, but the present inventors have estimated as follows.
By introducing a compound having an ionic group into the fiber, the melting point of the fiber itself is slightly lowered. Therefore, it is presumed that the substantial stretching conditions are different if the compound is not introduced. Therefore, in this invention, it is estimated that it extends | stretches at the temperature near melting | fusing point. That is, in the present invention, stretching is performed in a state where the molecular mobility is higher, and it is presumed that oriented crystallization is promoted, and therefore a fiber having a high degree of crystallinity can be obtained.

本発明により得られる繊維の繊度は特に限定されず、例えば０．１〜１００００ｄｔｅｘ、好ましくは１〜１０００ｄｔｅｘの繊度の繊維が広く使用できる。繊維の繊度はノズル径や延伸倍率により適宜調整すればよい。 The fineness of the fiber obtained by this invention is not specifically limited, For example, the fiber of the fineness of 0.1-10000 dtex, Preferably 1-1000 dtex can be used widely. What is necessary is just to adjust the fineness of a fiber suitably with a nozzle diameter or a draw ratio.

次に本発明の水溶性ＰＶＡ系繊維の製造方法について説明する。本発明においては、ＰＶＡ系ポリマーを水あるいは有機溶剤に溶解した紡糸原液を用いて後述する方法で繊維を製造することにより結晶化度が高く、機械的特性に優れ、且つ水溶解性に優れた繊維を効率良く安価に製造することができる。紡糸原液を構成する溶媒としては、例えばジメチルスルホキシド（以下、ＤＭＳＯと略記）、ジメチルアセトアミド、ジメチルホルムアミド、Ｎ−メチルピロリドンなどの極性溶媒やグリセリン、エチレングリコールなどの多価アルコール類、およびこれらとロダン塩、塩化リチウム、塩化カルシウム、塩化亜鉛などの膨潤性金属塩の混合物、さらにはこれら溶媒同士、あるいはこれら溶媒と水との混合物などが挙げられるが、これらの中でも、とりわけ水やＤＭＳＯがコスト、回収性等の工程通過性の点で最も好適である。 Next, the manufacturing method of the water-soluble PVA-type fiber of this invention is demonstrated. In the present invention, a fiber is produced by a method described later using a spinning stock solution in which a PVA polymer is dissolved in water or an organic solvent, so that the crystallinity is high, the mechanical properties are excellent, and the water solubility is excellent. A fiber can be manufactured efficiently and inexpensively. Examples of the solvent constituting the spinning dope include polar solvents such as dimethyl sulfoxide (hereinafter abbreviated as DMSO), dimethylacetamide, dimethylformamide, N-methylpyrrolidone, polyhydric alcohols such as glycerin and ethylene glycol, and these and rhodan. A mixture of salts, swellable metal salts such as lithium chloride, calcium chloride, zinc chloride, and the like, and a mixture of these solvents, or a mixture of these solvents and water, among these, water and DMSO are particularly cost, Most suitable in terms of process passability such as recoverability.

紡糸原液中のポリマー濃度は組成、重合度、溶媒によって異なるが、８〜４０質量％の範囲であることが好ましい。紡糸原液の吐出時の液温は、紡糸原液が分解、着色しない範囲であることが好ましく、具体的には５０〜１５０℃とすることが好ましい。 The polymer concentration in the spinning dope varies depending on the composition, degree of polymerization, and solvent, but is preferably in the range of 8 to 40% by mass. The liquid temperature at the time of discharging the spinning dope is preferably in a range in which the spinning dope is not decomposed or colored, and specifically 50 to 150 ° C. is preferable.

かかる紡糸原液をノズルから吐出して湿式紡糸あるいは乾湿式紡糸を行えばよく、ＰＶＡ系ポリマーに対して固化能を有する固化液に吐出すればよい。なお、湿式紡糸とは、紡糸ノズルから直接固化浴に紡糸原液を吐出する方法のことであり、一方乾湿式紡糸とは、紡糸ノズルから一旦任意の距離の空気中あるいは不活性ガス中に紡糸原液を吐出し、その後に固化浴に導入する方法のことである。 Such spinning dope may be discharged from a nozzle to perform wet spinning or dry / wet spinning, and may be discharged to a solidified liquid having a solidifying ability for a PVA polymer. Wet spinning is a method in which a spinning solution is directly discharged from a spinning nozzle to a solidification bath, while dry and wet spinning is a spinning solution in air or an inert gas at an arbitrary distance from the spinning nozzle. Is discharged and then introduced into the solidification bath.

本発明において用いる固化浴は、原液溶媒が有機溶媒の場合と水の場合では異なる。有機溶媒を用いた原液の場合には、得られる繊維強度等の点から固化浴溶媒と原液溶媒からなる混合液であることが好ましく、固化溶媒としては特に制限はないが、例えばメタノール、エタノール、プロパノ−ル、ブタノールなどのアルコール類、アセトン、メチルエチルケトン、メチルイソブチルケトンなどのケトン類等のＰＶＡ系ポリマーに対して固化能を有する有機溶媒を用いることができる。これらの中でも低腐食性及び溶剤回収の点でメタノールとＤＭＳＯとの組合せが好ましい。一方、紡糸原液が水溶液の場合、固化浴を構成する固化溶媒としては、芒硝、塩化ナトリウム、炭酸ナトリウム等のＰＶＡ系ポリマーに対して固化能を有する無機塩類の水溶液を用いることができる。 The solidification bath used in the present invention differs depending on whether the stock solution is an organic solvent or water. In the case of a stock solution using an organic solvent, it is preferably a mixed solution consisting of a solidification bath solvent and a stock solution solvent from the viewpoint of fiber strength and the like obtained, and the solidification solvent is not particularly limited, but for example, methanol, ethanol, An organic solvent capable of solidifying PVA-based polymers such as alcohols such as propanol and butanol, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone can be used. Among these, a combination of methanol and DMSO is preferable in terms of low corrosivity and solvent recovery. On the other hand, when the spinning dope is an aqueous solution, an aqueous solution of an inorganic salt having a solidifying ability with respect to a PVA polymer such as mirabilite, sodium chloride, and sodium carbonate can be used as a solidifying solvent constituting the solidifying bath.

次に固化された原糸から紡糸原液の溶媒を抽出除去するために、抽出浴を通過させるが、抽出時に同時に原糸を湿延伸することが、乾燥時の繊維間膠着抑制及び得られる繊維の機械的特性を向上させるうえで好ましい。その際の湿延伸倍率としては２〜６倍であることが工程性、生産性の点で好ましい。抽出溶媒としては固化溶媒単独あるいは原液溶媒と固化溶媒の混合液を用いることができる。 Next, in order to extract and remove the solvent of the spinning dope from the solidified yarn, it is passed through an extraction bath. It is preferable for improving the mechanical properties. In this case, the wet draw ratio is preferably 2 to 6 times in terms of processability and productivity. As the extraction solvent, a solidified solvent alone or a mixed solution of a stock solvent and a solidified solvent can be used.

湿延伸後、繊維を乾燥または延伸してＰＶＡ系繊維を製造すればよいが、本発明の目的とする繊維を得るためには、イオン性基を有する化合物を溶解した抽出浴を通過させて該化合物を繊維中に含浸させる。この場合、抽出浴で繊維が抽出溶媒により膨潤していることが繊維中へのイオン性基を有する化合物の均一浸透の点から好ましく、そのためには抽出溶媒はメタノール等のアルコール類や水であることが好ましい。すなわち紡糸工程中において繊維が十分に結晶化した後に抽出溶媒中で膨潤状態にある繊維に該化合物を含浸させ、その後の乾燥、延伸、熱処理などの工程で反応、導入させることにより実質的な延伸倍率が低下することはなく、引張強度などの機械的特性や水溶解性を兼備したＰＶＡ系繊維が得られる。 After the wet drawing, the fiber may be dried or drawn to produce a PVA fiber, but in order to obtain the target fiber of the present invention, the fiber is passed through an extraction bath in which a compound having an ionic group is dissolved. The compound is impregnated into the fiber. In this case, it is preferable that the fiber is swollen by the extraction solvent in the extraction bath from the viewpoint of uniform penetration of the compound having an ionic group into the fiber, and for this purpose, the extraction solvent is alcohol such as methanol or water. It is preferable. That is, the fiber is sufficiently stretched in the extraction solvent after the fiber is sufficiently crystallized during the spinning process, and then the compound is impregnated and then reacted and introduced in a process such as drying, stretching, and heat treatment. The magnification does not decrease, and a PVA fiber having mechanical properties such as tensile strength and water solubility can be obtained.

一方、例えばアルデヒド基やエステル基など、ＰＶＡ系ポリマーの有する水酸基と容易に反応する原子団を含む変性剤を原液から仕込んだ場合には、その段階で反応が進み、固化過程での結晶化が阻害され、その後の延伸性が低下し、結果として結晶化度が低く、したがって機械的特性の低い繊維しか得られない。また予めイオン性基を有する化合物をＰＶＡ系ポリマーに反応させたものを原料として使用した場合においても得られる繊維の結晶性は低くなり、それ故機械的特性の低い繊維しか得られない。さらには、延伸や熱処理後にローラータッチなどで該化合物を付与する方法では、十分な量が付与できないことに加えて、繊維への均一含浸ができず、再現性に乏しいものとなる。したがって先述したように、抽出溶媒中で膨潤状態にあるＰＶＡ系繊維に該化合物を含浸させておくことが好適である。 On the other hand, when a modifier containing an atomic group that easily reacts with a hydroxyl group of a PVA polymer, such as an aldehyde group or an ester group, is charged from the stock solution, the reaction proceeds at that stage, and crystallization during the solidification process occurs. Inhibited and subsequent drawability is reduced, resulting in fibers with low crystallinity and thus low mechanical properties. Further, even when a material obtained by reacting a compound having an ionic group with a PVA polymer in advance is used as a raw material, the crystallinity of the obtained fiber is lowered, and therefore, only a fiber having low mechanical properties can be obtained. Furthermore, in the method of applying the compound by roller touch or the like after stretching or heat treatment, in addition to being unable to provide a sufficient amount, the fiber cannot be uniformly impregnated, resulting in poor reproducibility. Therefore, as described above, it is preferable to impregnate the PVA fiber in a swollen state in the extraction solvent with the compound.

本発明の水溶性ＰＶＡ系繊維は、先述したように、イオン性基を有する化合物の導入量によって、水溶解温度を適宜コントロールすることが可能である。イオン性基を有する化合物の抽出浴への添加量は要求される水溶解特性に応じて適宜設定すればよいが、１〜５０ｇ／ｌの範囲であることが好ましい。添加量が１ｇ／ｌ未満の場合、本発明の目的とする水溶解特性が得られず、また５０ｇ／ｌを越える場合は反応が進みすぎて結晶化度が低くなり、機械的物性の低下や水中での収縮をもたらすので好ましくない。より好ましくは２〜３０ｇ／ｌである。 As described above, the water-soluble PVA fiber of the present invention can appropriately control the water dissolution temperature depending on the amount of the compound having an ionic group introduced. The amount of the compound having an ionic group added to the extraction bath may be appropriately set according to the required water solubility, but is preferably in the range of 1 to 50 g / l. If the addition amount is less than 1 g / l, the water solubility characteristic of the present invention cannot be obtained, and if it exceeds 50 g / l, the reaction proceeds so much that the crystallinity is lowered, and the mechanical properties are reduced. This is not preferable because it causes contraction in water. More preferably, it is 2-30 g / l.

このようにして固化から抽出などの紡糸工程中で繊維中に導入された該化合物を、紡糸後の乾燥、延伸、熱処理の何れかの工程での熱などにより反応させることで、本発明の水溶性ＰＶＡ系繊維を製造することができる。反応を進行させるために必要な乾燥、延伸、熱処理時の温度は特に制限はないが、繊維の機械的特性を発現させるための延伸等と同時に反応を進行させることを考慮すると、１００〜２４０℃の範囲であることが好ましい。温度が１００℃未満の場合、反応が進行しにくくなるとともに繊維の白化が生じ、そのため機械的物性の低下をもたらす。また２４０℃を越えると繊維の部分的な融解が生じ、この場合においても機械的物性の低下をもたらすので好ましくない。より好ましくは１２０〜２２０℃の範囲である。 The compound thus introduced into the fiber during the spinning process such as solidification to extraction is reacted with heat in any of the drying, stretching, and heat treatment steps after spinning, so that -Based PVA fibers can be produced. There is no particular limitation on the temperature required for drying, stretching, and heat treatment necessary for the reaction to proceed, but considering that the reaction proceeds simultaneously with the stretching for expressing the mechanical properties of the fiber, the temperature is 100 to 240 ° C. It is preferable that it is the range of these. When the temperature is lower than 100 ° C., the reaction is difficult to proceed and the whitening of the fiber occurs, resulting in a decrease in mechanical properties. On the other hand, if the temperature exceeds 240 ° C., partial melting of the fiber occurs, and in this case, mechanical properties are deteriorated, which is not preferable. More preferably, it is the range of 120-220 degreeC.

本発明の水溶性ＰＶＡ系繊維は、全延伸倍率を３倍以上にすることが好ましい。延伸倍率が３倍未満の場合には、繊維の機械的特性が損なわれる。なお、ここでいう延伸倍率とは、先述した乾燥前の固化浴中での湿延伸と乾燥後の延伸倍率の積である。例えば、湿延伸を３倍とし、その後の延伸を２倍とした場合の全延伸倍率は６倍となる。 The water-soluble PVA fiber of the present invention preferably has a total draw ratio of 3 times or more. If the draw ratio is less than 3, the mechanical properties of the fiber are impaired. The stretch ratio here is the product of the above-described wet stretching in the solidification bath before drying and the stretch ratio after drying. For example, when the wet stretching is 3 times and the subsequent stretching is 2 times, the total stretching ratio is 6 times.

本発明の水溶性ＰＶＡ系繊維は、例えばカットファイバー、フィラメント、紡績糸、紐状物、ロープ、フィブリル等の形態で使用可能である。また該繊維を用いて、例えば不織布、織編物等を作製しても構わないが、水溶性が要求される用途からみると、ケミカルレース用基布などの不織布とするのがより好適である。 The water-soluble PVA fiber of the present invention can be used in the form of, for example, cut fiber, filament, spun yarn, string-like material, rope, fibril and the like. In addition, for example, a nonwoven fabric or a woven or knitted fabric may be produced using the fiber, but it is more preferable to use a nonwoven fabric such as a base fabric for chemical lace from the viewpoint of water-soluble applications.

本発明の水溶性ＰＶＡ系繊維を用いて不織布を製造する場合、製造方法は従来公知の方法が用いられる。具体的にはニードルパンチ法、エンボス法、フォームボンド法、熱融着繊維を混合した加熱法（エンボス、熱風、金型成形）、バインダー接着法、水流絡合法、メルトブローン法やスパンボンド法で製造した不織布との貼り合せやこれらの組合せなどが挙げられるが、不織布の目的とする品質に応じて適宜選択すればよい。 When manufacturing a nonwoven fabric using the water-soluble PVA-type fiber of this invention, a conventionally well-known method is used for a manufacturing method. Specifically, it is manufactured by the needle punch method, embossing method, foam bonding method, heating method (embossing, hot air, mold molding) mixed with heat-bonding fibers, binder bonding method, hydroentanglement method, melt blown method and spunbond method. Bonding with a non-woven fabric, a combination of these, and the like may be mentioned, but it may be selected as appropriate according to the desired quality of the non-woven fabric.

上記不織布中における本発明の水溶性ＰＶＡ系繊維の含有率は５〜１００質量％であることが好ましい。含有率が５質量％未満である場合、水溶性特性が要求される用途への使用が困難になる。また本発明の水溶性ＰＶＡ系繊維は熱圧着性や十分な強伸度等の繊維物性を有していることなどから、本発明の水溶性ＰＶＡ系繊維を１００質量％不織布に使用してエンボス加工やニードルパンチ加工することが可能である。ただし、目的とする品質やコストに応じて他の繊維と併用してもよく、例えばパルプ、綿等の天然繊維、レーヨン、キュプラ等の再生繊維、アセテート、プロミックス等の半合成繊維、ポリエステル繊維、アクリル繊維、ポリアミド系繊維（ナイロン、アラミド等）、非水溶性のＰＶＡ系繊維等の合成繊維と混合もしくは積層して使用してもかまわない。また必要に応じて本発明の水溶性ＰＶＡ系繊維からなる不織布を他の素材、たとえばフィルム、金属、樹脂等と複合することもできる。 The content of the water-soluble PVA fiber of the present invention in the nonwoven fabric is preferably 5 to 100% by mass. When the content is less than 5% by mass, it becomes difficult to use in applications that require water-soluble properties. Moreover, since the water-soluble PVA fiber of the present invention has fiber physical properties such as thermocompression bonding and sufficient strength and elongation, the water-soluble PVA fiber of the present invention is embossed using 100% by mass of the nonwoven fabric. Processing and needle punching are possible. However, it may be used in combination with other fibers according to the intended quality and cost. For example, natural fibers such as pulp and cotton, regenerated fibers such as rayon and cupra, semi-synthetic fibers such as acetate and promix, polyester fibers In addition, it may be used by mixing or laminating with synthetic fibers such as acrylic fibers, polyamide fibers (nylon, aramid, etc.), water-insoluble PVA fibers and the like. Moreover, the nonwoven fabric which consists of the water-soluble PVA type fiber of this invention can also be combined with another raw material, for example, a film, a metal, resin etc. as needed.

以下、実施例により本発明をより詳細に説明するが、本発明は本実施例により何等限定されるものではない。なお以下の実施例において、繊維中のイオン性化合物の反応度、繊維の結晶化度、繊維の水中溶断温度、繊維の引張強度は下記の方法により測定したものを示す。 EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by this Example. In the following examples, the reactivity of the ionic compound in the fiber, the crystallinity of the fiber, the fusing temperature of the fiber in water, and the tensile strength of the fiber are those measured by the following methods.

［繊維中のイオン性化合物の反応度モル％］
反応度の測定は、日本電子社製核磁気共鳴装置（ＮＭＲ）を用いて行った。ＰＶＡ繊維を溶液温度５０〜１４０℃のＤＭＳＯ溶液に溶解せしめ、^１３Ｃ−ＮＭＲによって、反応により生成する構造（アセタール）に帰属されるピーク（化学シフト＝１００ｐｐｍ）とＰＶＡ中のＣＨ_２基ピークの面積比から求めた。 [Reactivity of ionic compounds in fiber mol%]
The degree of reactivity was measured using a nuclear magnetic resonance apparatus (NMR) manufactured by JEOL. The PVA fiber was dissolved in a DMSO solution having a solution temperature of 50 to 140 ° C., and the peak (chemical shift = 100 ppm) attributed to the structure (acetal) produced by the reaction and the CH ₂ group peak in PVA were analyzed by ¹³ C-NMR. It was determined from the area ratio.

［繊維の結晶化度（Ｘｃ）％］
ＰｅｒｋｉｎＥｌｍｅｒ社製Ｐｙｒｉｓ−１型示査走査型熱量計を用いて、試料の全融解エンタルピー（ΔＨ_ｏｂｓ）を測定した。測定条件は、昇温速度８０℃／分とし、以下の式より質量結晶化度を算出した。なお標準物質として、インジウム及び鉛を用いて、融点、融解熱の補正を行った。
Ｘｃ（％）＝ΔＨ_ｏｂｓ／ΔＨ_ｃａｌ×１００
ΔＨ_ｏｂｓ：実測全融解熱量（Ｊ／ｇ）
ΔＨ_ｃａｌ：完全結晶の融解熱量（１７４．５Ｊ／ｇ） [Fiber crystallinity (Xc)%]
The total melting enthalpy (ΔH _obs ) of the sample was measured using a Perkin Elmer Pyris-1 type scanning scanning calorimeter. The measurement conditions were a heating rate of 80 ° C./min, and the mass crystallinity was calculated from the following equation. Note that the melting point and heat of fusion were corrected using indium and lead as standard materials.
Xc (%) = ΔH _obs / ΔH _cal × 100
ΔH _obs : Actual total heat of fusion (J / g)
ΔH _cal : Calorie of complete crystal (174.5 J / g)

［繊維の水中溶断温度（Ｗｔｂ） ℃］
所定の荷重（２ｍｇ／ｄｔｅｘ）をかけた繊維試料を温度３℃に設定した氷水中に吊るし、２℃／分の昇温速度で水温を昇温させて、試料が破断して荷重が落下するまでの水温と収縮率の関係を測定し、荷重が落下した時の温度をＷｔｂとした。 [Fusing temperature of fibers in water (Wtb) ° C]
A fiber sample subjected to a predetermined load (2 mg / dtex) is suspended in ice water set at a temperature of 3 ° C., the water temperature is raised at a rate of temperature increase of 2 ° C./min, the sample breaks and the load drops. The relationship between the water temperature and the shrinkage rate was measured, and the temperature when the load dropped was defined as Wtb.

［繊維強度ｃＮ／ｄｔｅｘ］
ＪＩＳＬ１０１３に準じて、予め調湿されたヤーンを試長２０ｃｍ、初荷重０．２５ｃＮ／ｄｔｅｘ及び引張速度５０％／分の条件で測定し、ｎ＝２０の平均値を採用した。また繊維繊度（ｄｔｅｘ）は質量法により求めた。 [Fiber strength cN / dtex]
In accordance with JIS L1013, a yarn conditioned in advance was measured under the conditions of a test length of 20 cm, an initial load of 0.25 cN / dtex and a tensile speed of 50% / min, and an average value of n = 20 was adopted. The fiber fineness (dtex) was determined by a mass method.

［実施例１］
（１）粘度平均重合度１７００、ケン化度９６．０モル％のＰＶＡをＰＶＡ濃度２３質量％となるようにＤＭＳＯ中に添加し、９０℃にて窒素雰囲気下で加熱溶解した。得られた紡糸原液を、孔径０．０８ｍｍ、ホール数１０８のノズルを通して液温５℃のメタノール／ＤＭＳＯ＝７０／３０（質量比）よりなる固化浴中に乾湿式紡糸した。
（２）得られた固化糸を固化浴と同じメタノール／ＤＭＳＯ組成の第２浴に浸漬し、次いで液温２５℃のメタノール浴中で３倍の湿延伸を施した。その後、和光純薬（株）製グリオキシル酸を１０ｇ／ｌ溶解したメタノール浴（抽出浴）に浸漬した後、１２０℃の熱風で乾燥し、紡糸原糸を得た。次いで、得られた紡糸原糸を１６０℃の熱風延伸炉中で総延伸倍率（湿延伸倍率×熱風炉延伸倍率）が６倍になるように延伸した。得られた繊維の性能評価結果を表１に示す。
（３）得られた繊維においてグリオキシル酸の反応度は０．９モル％であった。また得られた繊維の繊維物性は単糸繊度２．０ｄｔｅｘ、繊維の結晶化度３８％、水中溶断温度２０℃、繊維強度７．５ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 1]
(1) PVA having a viscosity average polymerization degree of 1700 and a saponification degree of 96.0 mol% was added to DMSO so as to have a PVA concentration of 23% by mass, and heated and dissolved in a nitrogen atmosphere at 90 ° C. The obtained spinning solution was dry-wet-spun into a solidification bath of methanol / DMSO = 70/30 (mass ratio) at a liquid temperature of 5 ° C. through a nozzle having a hole diameter of 0.08 mm and a hole number of 108.
(2) The obtained solidified yarn was dipped in a second bath having the same methanol / DMSO composition as the solidified bath, and then wet-stretched 3 times in a methanol bath at a liquid temperature of 25 ° C. Then, after being immersed in a methanol bath (extraction bath) in which 10 g / l of glyoxylic acid manufactured by Wako Pure Chemical Industries, Ltd. was dissolved, it was dried with hot air at 120 ° C. to obtain a spinning yarn. Next, the obtained spinning yarn was drawn in a hot air drawing furnace at 160 ° C. so that the total draw ratio (wet draw ratio × hot air furnace draw ratio) was 6 times. Table 1 shows the performance evaluation results of the obtained fibers.
(3) The reactivity of glyoxylic acid in the obtained fiber was 0.9 mol%. The fiber properties of the obtained fiber were a single yarn fineness of 2.0 dtex, a fiber crystallinity of 38%, a fusing temperature of 20 ° C. in water, a fiber strength of 7.5 cN / dtex, and the appearance of the fiber was good. And was superior to conventional water-soluble PVA fibers.

［実施例２］
グリオキシル酸のカルボン酸部位を、水酸化ナトリウムで５０％中和したものを用いた以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表１に示す。得られた繊維においてグリオキシル酸の反応度は０．８モル％であった。また得られた繊維の繊維物性は単糸繊度２．１ｄｔｅｘ、繊維の結晶化度４３％、水中溶断温度１５℃、繊維強度７．６ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 2]
A fiber was obtained by spinning and stretching under the same conditions as in Example 1 except that the carboxylic acid portion of glyoxylic acid was neutralized with 50% sodium hydroxide. Table 1 shows the performance evaluation results of the obtained fibers. In the obtained fiber, the reactivity of glyoxylic acid was 0.8 mol%. The fiber properties of the obtained fiber were a single yarn fineness of 2.1 dtex, a fiber crystallinity of 43%, a fusing temperature of 15 ° C. in water, and a fiber strength of 7.6 cN / dtex. And was superior to conventional water-soluble PVA fibers.

［実施例３］
グリオキシル酸のカルボン酸部位を、水酸化ナトリウムで５０％中和したものを用い、且つ抽出浴への溶解量を５ｇ／ｌに変更した以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表１に示す。得られた繊維においてグリオキシル酸の反応度は０．３モル％であった。また得られた繊維の繊維物性は単糸繊度２．０ｄｔｅｘ、繊維の結晶化度４２％、水中溶断温度２０℃、繊維強度７．３ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 3]
The fiber was spun and stretched under the same conditions as in Example 1 except that the carboxylic acid portion of glyoxylic acid was neutralized with 50% sodium hydroxide and the amount dissolved in the extraction bath was changed to 5 g / l. Got. Table 1 shows the performance evaluation results of the obtained fibers. In the obtained fiber, the reactivity of glyoxylic acid was 0.3 mol%. The fiber properties of the obtained fiber were a single yarn fineness of 2.0 dtex, a fiber crystallinity of 42%, an underwater fusing temperature of 20 ° C., a fiber strength of 7.3 cN / dtex, and the appearance of the fiber was good with no yarn spots. It was superior to conventional water-soluble PVA fibers.

［実施例４］
グリオキシル酸のカルボン酸部位を、水酸化ナトリウムで８０％中和したものを用いた以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。結果を表１に示す。得られた繊維においてグリオキシル酸の反応度は１．０モル％であった。また得られた繊維の繊維物性は単糸繊度２．４ｄｔｅｘ、繊維の結晶化度４８％、水中溶断温度１０℃、繊維強度７．７ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 4]
A fiber was obtained by spinning and drawing under the same conditions as in Example 1 except that the carboxylic acid portion of glyoxylic acid was neutralized with 80% sodium hydroxide. The results are shown in Table 1. In the obtained fiber, the reactivity of glyoxylic acid was 1.0 mol%. The fiber properties of the obtained fiber were a single yarn fineness of 2.4 dtex, a fiber crystallinity of 48%, a fusing temperature of 10 ° C. in water, a fiber strength of 7.7 cN / dtex, and the appearance of the fiber was good with no yarn spots. And was superior to conventional water-soluble PVA fibers.

［実施例５］
粘度平均重合度１７００、ケン化度９８．０モル％のＰＶＡを使用し、延伸温度を２００℃、延伸倍率を１０倍とした以外は実施例３と同様の条件で紡糸、延伸し、繊維を得た。得られた繊維においてグリオキシル酸の反応度は０．９モル％であった。また得られた繊維の繊維物性は単糸繊度２．０ｄｔｅｘ、繊維の結晶化度６０％、水中溶断温度６５℃、繊維強度８．５ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 5]
The fiber was spun and stretched under the same conditions as in Example 3 except that PVA having a viscosity average polymerization degree of 1700 and a saponification degree of 98.0 mol% was used, the stretching temperature was 200 ° C., and the stretching ratio was 10 times. Obtained. In the obtained fiber, the reactivity of glyoxylic acid was 0.9 mol%. Further, the fiber properties of the obtained fiber are a single yarn fineness of 2.0 dtex, a fiber crystallinity of 60%, an underwater melting temperature of 65 ° C., a fiber strength of 8.5 cN / dtex, and the appearance of the fiber is good and the yarn spots are And was superior to conventional water-soluble PVA fibers.

［実施例６］
（１）粘度平均重合度１７００、ケン化度９６．０モル％のＰＶＡをＰＶＡ濃度１６質量％となるように水に投入し、９０℃にて窒素雰囲気下で加熱溶解した。得られた紡糸原液を孔径０．１６ｍｍ、ホール数１０８のノズルを通して飽和芒硝水溶液からなる凝固浴中へ湿式紡糸した。
（２）さらに、得られた繊維を水中で３倍に湿延伸した後、イオン性基であるカルボン酸部位が、５０％水酸化ナトリウムで中和されたグリオキシル酸ナトリウム中和物が１０ｇ／ｌ添加された水浴（抽出浴）を通過させることにより芒硝の洗浄及びグリオキシル酸ナトリウム中和物の繊維内部への含浸を行ない、紡糸原糸を得た。次いで得られた紡糸原糸を１６０℃の熱風延伸炉中で総延伸倍率が６倍になるように延伸した。得られた繊維の性能評価結果を表１に示す。
（３）得られた繊維において、グリオキシル酸の反応度は１．０モル％であった。また得られた繊維の繊維物性は単糸繊度２．２ｄｔｅｘ、繊維の結晶化度４５％、水中溶断温度１８℃、繊維強度７．０ｃＮ／ｄｔｅｘであり、さらに繊維の外観は良好で糸斑等はなく、従来の水溶性ＰＶＡ系繊維より優れるものであった。 [Example 6]
(1) PVA having a viscosity average polymerization degree of 1700 and a saponification degree of 96.0 mol% was added to water so as to have a PVA concentration of 16% by mass, and heated and dissolved in a nitrogen atmosphere at 90 ° C. The obtained spinning dope was wet-spun into a coagulation bath composed of a saturated sodium sulfate aqueous solution through a nozzle having a hole diameter of 0.16 mm and a hole number of 108.
(2) Furthermore, after the obtained fiber was wet-stretched 3 times in water, the neutralized product of sodium glyoxylate in which the carboxylic acid site as an ionic group was neutralized with 50% sodium hydroxide was 10 g / l. By passing through the added water bath (extraction bath), washing of the salt cake and impregnation of the neutralized product of sodium glyoxylate into the inside of the fiber were carried out to obtain a spinning yarn. Next, the obtained spinning yarn was drawn in a hot air drawing furnace at 160 ° C. so that the total draw ratio was 6 times. Table 1 shows the performance evaluation results of the obtained fibers.
(3) In the obtained fiber, the reactivity of glyoxylic acid was 1.0 mol%. The fiber properties of the obtained fiber were a single yarn fineness of 2.2 dtex, a fiber crystallinity of 45%, a fusing temperature of 18 ° C. in water, a fiber strength of 7.0 cN / dtex, and the appearance of the fiber was good with no yarn spots. And was superior to conventional water-soluble PVA fibers.

［比較例１］
グリオキシル酸を添加しない以外は、実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の外観は良好で糸斑等はなく、単糸繊度２．０ｄｔｅｘ、水中溶断温度は３０℃であったが、繊維の結晶化度が３５％であるにもかかわらず繊維強度５．５ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 1]
A fiber was obtained by spinning and drawing under the same conditions as in Example 1 except that glyoxylic acid was not added. Table 2 shows the performance evaluation results of the obtained fibers. The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 2.0 dtex, the fusing temperature in water was 30 ° C., but the fiber strength was 5.5% despite the fiber crystallinity being 35%. It was as low as 5 cN / dtex.

［比較例２］
グリオキシル酸の添加量を０．５ｇ／ｌとした以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の外観は良好で糸斑等はなく、単糸繊度２．１ｄｔｅｘ、水中溶断温度は２８℃であったが、グリオキシル酸の反応度が０．００２モル％と低いため、繊維の結晶化度が３３％であるにもかかわらず、繊維強度５．６ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 2]
A fiber was obtained by spinning and drawing under the same conditions as in Example 1 except that the amount of glyoxylic acid added was 0.5 g / l. Table 2 shows the performance evaluation results of the obtained fibers. The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 2.1 dtex, the fusing temperature in water was 28 ° C., but the reactivity of glyoxylic acid was as low as 0.002 mol%. Although the degree of conversion was 33%, the fiber strength was as low as 5.6 cN / dtex.

［比較例３］
グリオキシル酸の添加量を１００ｇ／ｌとした以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の外観は良好で糸斑等はなく、単糸繊度２．２ｄｔｅｘ、水中溶断温度は５０℃であったが、グリオキシル酸の反応度が１０．１モル％と高すぎるため、繊維の結晶化度が３３％であるにもかかわらず、繊維強度５．９ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 3]
A fiber was obtained by spinning and drawing under the same conditions as in Example 1 except that the amount of glyoxylic acid added was 100 g / l. Table 2 shows the performance evaluation results of the obtained fibers. The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 2.2 dtex, the fusing temperature in water was 50 ° C., but the reactivity of glyoxylic acid was too high at 10.1 mol%. Despite the crystallinity of 33%, the fiber strength was as low as 5.9 cN / dtex.

［比較例４］
グリオキシル酸を抽出浴に溶解せず、延伸後ローラータッチ（後付与）にてグリオキシル酸を繊維に付着させた以外は、実施例１と同じ条件にて紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の単糸繊度は２．５ｄｔｅｘであった。またグリオキシル酸の反応度は１．１モル％、水中溶断温度は４２℃であったが、グリオキシル酸は繊維表面にのみ反応しているため、繊維の結晶化度が３２％であるにもかかわらず、繊維強度５．５ｃＮ／ｄｔｅｘであった。 [Comparative Example 4]
A fiber was obtained by spinning and stretching under the same conditions as in Example 1 except that glyoxylic acid was not dissolved in the extraction bath, and glyoxylic acid was adhered to the fiber by roller touch after stretching (post-attachment). Table 2 shows the performance evaluation results of the obtained fibers. The single fiber fineness of the obtained fiber was 2.5 dtex. The reactivity of glyoxylic acid was 1.1 mol% and the fusing temperature in water was 42 ° C. However, since glyoxylic acid reacts only on the fiber surface, the crystallinity of the fiber is 32%. The fiber strength was 5.5 cN / dtex.

［比較例５］
先述した特許文献５の追試として、グリオキシル酸を原液に添加し、抽出浴には添加しない以外は実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の外観は良好で糸斑等はなく、単糸繊度は２．３ｄｔｅｘ、水中溶断温度は３４℃であったが、グリオキシル酸の反応度が９．９モル％と高すぎるため、繊維の結晶化度が２５％と低く、そのため繊維強度も５．０ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 5]
As a supplementary test of Patent Document 5 described above, fibers were obtained by spinning and drawing under the same conditions as in Example 1 except that glyoxylic acid was added to the stock solution and not added to the extraction bath. Table 2 shows the performance evaluation results of the obtained fibers. The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 2.3 dtex, the fusing temperature in water was 34 ° C., but the reactivity of glyoxylic acid was too high at 9.9 mol%, The crystallinity of the fiber was as low as 25%, and therefore the fiber strength was as low as 5.0 cN / dtex.

［比較例６］
アルデヒドをベンズアルデヒドとした以外は、実施例１と同じ条件で紡糸、延伸し、繊維を得た。得られた繊維の性能評価結果を表２に示す。得られた繊維の外観は良好で糸斑等はなく、単糸繊度は２．０ｄｔｅｘであった。またベンズアルデヒドの反応度は１．０モル％、水中溶断温度は５５℃であったが、結晶化度３４％であるにもかかわらず、繊維強度４．９ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 6]
A fiber was obtained by spinning and drawing under the same conditions as in Example 1 except that the aldehyde was changed to benzaldehyde. Table 2 shows the performance evaluation results of the obtained fibers. The appearance of the obtained fiber was good, there were no yarn spots, and the single yarn fineness was 2.0 dtex. The reactivity of benzaldehyde was 1.0 mol% and the fusing temperature in water was 55 ° C, but the fiber strength was as low as 4.9 cN / dtex despite the crystallinity of 34%.

［比較例７］
（１）先述した特許文献３の追試として、粘度平均重合度１２００、ケン化度９６．０モル％のＰＶＡをＰＶＡ濃度３３質量％となるように水に溶解し、これを孔径０．１ｍｍ、ホール数５０のノズルで５００ｍ／分で乾式紡糸し、次いで１３５℃で５倍に延伸し、繊維を得た。
（２）得られた繊維の外観は良好で糸斑等はなく、単糸繊度４．０ｄｔｅｘ、水中溶断温度は４５℃であったが、結晶化度が３０％であるにもかかわらず、繊維強度は４．８ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 7]
(1) As a supplementary test of Patent Document 3 described above, PVA having a viscosity average polymerization degree of 1200 and a saponification degree of 96.0 mol% was dissolved in water so that the PVA concentration was 33% by mass, and this was dissolved in a pore diameter of 0.1 mm, Dry spinning was performed at 500 m / min with a nozzle having 50 holes, and then stretched 5 times at 135 ° C. to obtain fibers.
(2) The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 4.0 dtex, the fusing temperature in water was 45 ° C., but the fiber strength was high despite the crystallinity being 30%. Was as low as 4.8 cN / dtex.

［比較例８］
（１）先述した特許文献１の追試として、粘度平均重合度４００、ケン化度９９．９モル％のＰＶＡをＰＶＡ濃度３９．７質量％となるように水に溶解し、これにホウ酸ナトリウムを０．３質量部加えて紡糸原液を調製した。この原液を孔径０．１ｍｍ、ホール数５０のノズルで５００ｍ／分で乾式紡糸し、次いで１３０℃で４倍に延伸し、繊維を得た。
（２）得られた繊維の外観は良好で糸斑等はなく、単糸繊度５．０ｄｔｅｘ、水中溶断温度７０℃であったが、ＰＶＡの重合度が低いため、結晶化度が３５％であるにもかかわらず、繊維強度は２．７ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 8]
(1) As a follow-up to Patent Document 1 described above, PVA having a viscosity average polymerization degree of 400 and a saponification degree of 99.9 mol% was dissolved in water so that the PVA concentration would be 39.7% by mass, and sodium borate was dissolved therein. Was added to prepare a spinning dope. This stock solution was dry-spun at 500 m / min with a nozzle having a hole diameter of 0.1 mm and a hole number of 50, and then stretched 4 times at 130 ° C. to obtain a fiber.
(2) Appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 5.0 dtex, the fusing temperature in water was 70 ° C., but the degree of crystallization was 35% because the polymerization degree of PVA was low. Nevertheless, the fiber strength was as low as 2.7 cN / dtex.

［比較例９］
（１）先述した特許文献２の追試として、粘度平均重合度１７００、ケン化度９８．５モル％のＰＶＡをＰＶＡ濃度１６．０質量％となるように水に溶解し、得られた紡糸原液を孔径０．１６ｍｍ、ホール数１０８のノズルを通して飽和芒硝水溶液からなる液温４０℃の凝固浴中へ湿式紡糸した。得られた繊維を水中で３倍に湿延伸した後、１２０℃で乾燥し、さらに２１５℃で熱処理して繊維を得た。
（２）得られた繊維の外観は良好で糸斑等はなく、単糸繊度１０．０ｄｔｅｘ、水中溶断温度８０℃であったが、繊維の延伸条件が湿延伸のみであったため、結晶化度が４０％であるにもかかわらず、繊維強度は４．７ｃＮ／ｄｔｅｘと低いものであった。 [Comparative Example 9]
(1) As a follow-up to Patent Document 2 described above, PVA having a viscosity average polymerization degree of 1700 and a saponification degree of 98.5 mol% was dissolved in water so that the PVA concentration was 16.0% by mass, and the obtained spinning dope This was wet-spun into a coagulation bath composed of a saturated sodium sulfate aqueous solution at a liquid temperature of 40 ° C. through a nozzle having a hole diameter of 0.16 mm and a hole number of 108. The obtained fiber was wet-stretched 3 times in water, dried at 120 ° C., and further heat-treated at 215 ° C. to obtain a fiber.
(2) The appearance of the obtained fiber was good, there was no yarn unevenness, the single yarn fineness was 10.0 dtex, the fusing temperature in water was 80 ° C, but the fiber drawing condition was only wet drawing, so the crystallinity was Despite being 40%, the fiber strength was as low as 4.7 cN / dtex.

表１の結果から明らかなように、本発明の水溶性ＰＶＡ系繊維は、水溶解性に優れ、且つ優れた繊維強度を兼ね備えている。さらにはイオン性基の中和度により、水溶解性を容易に制御することが可能である。一方、表２の結果から明らかなように、従来の技術や本発明の構成要件を満足しないイオン性基を有する化合物を用いた場合や、イオン性基を有する化合物の反応度が本発明の条件を満足しないものは、本発明の繊維に比べて結晶化度が低いにもかかわらず水中溶断温度が高くなる傾向があり、また得られる繊維の繊維強度が低いものとなる。 As is apparent from the results in Table 1, the water-soluble PVA fiber of the present invention has excellent water solubility and excellent fiber strength. Furthermore, water solubility can be easily controlled by the degree of neutralization of the ionic group. On the other hand, as is clear from the results in Table 2, when a compound having an ionic group that does not satisfy the constituent requirements of the prior art or the present invention is used, the reactivity of the compound having an ionic group is the condition of the present invention. Those not satisfying the above have a tendency that the fusing temperature in water tends to be high although the crystallinity is low as compared with the fiber of the present invention, and the fiber strength of the obtained fiber is low.

さらに実施例１〜６の繊維を用いて不織布とし、刺繍を行ったが、刺繍針による繊維の切断はなく、綺麗な刺繍ができた。一方、比較例１〜９の繊維を用いて不織布とし、刺繍を行った場合は、繊維強度が劣るため刺繍針によって繊維が切断したり、繊維表面の破損等がみられ、綺麗な刺繍ができなかった。 Further, the fibers of Examples 1 to 6 were used to make a nonwoven fabric and embroidery was performed, but the fibers were not cut with an embroidery needle, and beautiful embroidery was achieved. On the other hand, when the non-woven fabric is used with the fibers of Comparative Examples 1 to 9 and the embroidery is performed, the fiber strength is inferior, so the fibers are cut by the embroidery needle, the fiber surface is damaged, etc. There wasn't.

本発明によれば、従来技術では達成することができなかった、水溶解特性と引張強度をはじめとする機械的特性を兼備した水溶性ＰＶＡ系繊維を提供することができる。また本発明の水溶性ＰＶＡ系繊維は特別な工程を必要とせず、通常の紡糸、延伸工程で安価に製造可能である。さらに本発明の水溶性ＰＶＡ系繊維は水溶解性を適宜制御可能であり、ケミカルレース用基布や紡績糸をはじめとして多くの用途に極めて有効に使用されることが期待される。 ADVANTAGE OF THE INVENTION According to this invention, the water-soluble PVA type fiber which has the mechanical characteristics including the water solubility characteristic and tensile strength which was not able to be achieved by the prior art can be provided. Further, the water-soluble PVA fiber of the present invention does not require a special process and can be manufactured at a low cost by ordinary spinning and drawing processes. Furthermore, the water-soluble PVA fiber of the present invention can be appropriately controlled in water solubility, and is expected to be used extremely effectively in many applications including chemical lace base fabric and spun yarn.

本発明の水溶性ＰＶＡ系繊維と、特開平７−４２０１９号公報および特開平７−９０７１４号公報に記載されている水溶性繊維および二チビ製「ソルブロン」各銘柄について、それぞれの水中溶断温度（Ｗｔｂ）と繊維の結晶化度（Ｘｃ）の関係を示す図。Regarding the water-soluble PVA fiber of the present invention, the water-soluble fiber described in JP-A-7-42019 and JP-A-7-90714, and each brand of “SOLBRON” manufactured by Nichibi, each fusing temperature in water ( The figure which shows the relationship between Wtb) and the crystallinity degree (Xc) of a fiber.

Claims

イオン性基を有する化合物が０．０１〜５モル％反応されてなり、繊維の結晶化度（Ｘｃ／％）及び水中溶断温度（Ｗｔｂ／℃）の関係が以下の（１）式を満たすことを特徴とする水溶性ポリビニルアルコール系繊維。

A compound having an ionic group is reacted in an amount of 0.01 to 5 mol%, and the relationship between the fiber crystallinity (Xc /%) and the fusing temperature in water (Wtb / ° C) satisfies the following formula (1). Water-soluble polyvinyl alcohol fiber characterized by

イオン性基を有する化合物がグリオキシル酸またはグリオキシル酸の中和物であることを特徴とする請求項１記載の水溶性ポリビニルアルコール系繊維。 The water-soluble polyvinyl alcohol fiber according to claim 1, wherein the compound having an ionic group is glyoxylic acid or a neutralized product of glyoxylic acid.

重合度１０００〜４０００、及びケン化度８８モル％以上であるポリビニルアルコール系ポリマーを有機溶媒に溶解して得た紡糸原液を、該ポリマーに対して固化能を有する有機溶媒を主体とする固化浴に湿式または乾湿式紡糸し、次いでイオン性基を有する化合物が１〜５０ｇ／ｌ溶解された抽出浴を通して繊維中に該化合物を含浸させ、乾燥、延伸、熱処理の何れかの工程で反応して導入させると共に、全工程における全延伸倍率を３倍以上とする請求項１または２記載の水溶性ポリビニルアルコール系繊維の製造方法。
A spinning solution obtained by dissolving a polyvinyl alcohol polymer having a polymerization degree of 1000 to 4000 and a saponification degree of 88 mol% or more in an organic solvent, a solidification bath mainly composed of an organic solvent having a solidifying ability for the polymer Then, the fiber is impregnated into the fiber through an extraction bath in which 1 to 50 g / l of the compound having an ionic group is dissolved, and reacted in any step of drying, stretching and heat treatment. The method for producing a water-soluble polyvinyl alcohol fiber according to claim 1 or 2, wherein the total draw ratio in all steps is 3 times or more while being introduced.