TW200536968A - Water-soluble polyvinyl alcohol fibers and nonwoven fabric comprising them - Google Patents

Abstract

Provided are water-soluble PVA fibers having practicable fiber properties such as good mechanical properties and chemical resistance not detracting from their original water-solubility, and a water-soluble nonwoven fabric comprising the fibers. The nonwoven fabric also has practicable properties such as good mechanical properties and chemical resistance, and has many applications, for example, for base fabrics for chemical lace. The water-soluble PVA fibers are reacted with from 0.01 to 5 mol% of an ionic group-having compound and satisfy the following relational formula in which Xcf (%) indicates the degree of crystallinity of the fibers and Wtb (DEG C) indicates the dissolving temperature in water of the fibers: Wtb < 2.50Xcf-70, wherein 30% ≤ Xcf ≤ 80%.

Description

200536968 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to practically applicable fiber properties that can simultaneously have excellent mechanical properties and chemical resistance, without detracting from the original water-soluble water-soluble polyvinyl alcohol. (Hereinafter referred to as "PVA") fiber, and a non-woven fabric composed of the fiber. This fiber can be used very effectively for many applications, such as a base fabric for chemical lace. [Prior Art] [Background Art] Until now, PVA-based fibers, such as cellulose of carboxymethyl cellulose fibers Fibers, polyalginic fibers, and polyalkylene fibers are conventional water-soluble fibers. Among these, only PVA-based fibers have excellent mechanical properties and chemical resistance, which are sufficient in their non-woven step through carding or needle-punching, in the woven step in woven fabrics, or in the knitting of knitted fabrics. It has stable processability during the chemical conversion step. In recent years, global environmental protection and consumer protection have been strongly desired. PVA-based fibers are proven to be biodegradable in the natural environment, and from the standpoint of environmental protection, we expect water-soluble PVA-based fibers to be the most suitable fibers. Regarding the method for producing water-soluble PVA-based fibers, for example, a method has been proposed which uses a PVA-based polymer having a low degree of polymerization having an average degree of polymerization of from 200 to 500 to produce a method having improved water solubility, specifically, It is revealed that this type of PVA-based fiber is one that can be quickly dissolved in water at 5 ° C or below (for example, see Patent Document 1). However, since 200536968 uses a PVA polymer with such a low degree of polymerization, the degree of crystallinity of the fibers obtained cannot be improved, so the mechanical properties of the fibers are poor and the practical applicability of the fibers is limited. In addition, because the fiber contains boric acid or borate, the waste water discharged after dissolving and removing water-soluble fibers contains a large amount of boric acid. Therefore, there is a problem that some specific treatment methods and devices are required to treat wastewater. On the other hand, a manufacturing method of PVA-based fibers which can be dissolved at 50 ° C or below has been disclosed, which comprises wet-spinning an aqueous solution of a PVA-based polymer having a low degree of saponification into, for example, crystalline sodium sulfate (Glaubers salt) in a concentrated aqueous solution of salts, and then the obtained fiber is stretched at a low elongation ratio (for example, see Patent Document 2). In addition, a method for producing a PVA-based fiber that can be dissolved at a low temperature has been proposed, which is performed by spinning a PVA-based polymer having a low degree of saponification in a dry-wet spinning mode, and then the obtained fiber is subjected to spinning. It is produced by stretching at a low elongation ratio (for example, see Patent Document 3). Furthermore, a low-temperature water-soluble PVA-based fiber is also proposed, which is a solution of a PVA-based polymer having a low degree of saponification in an organic solvent such as dimethylarsin (hereinafter referred to as "φ DMSO") It is produced by spinning into a coagulation bath such as methanol (for example, see Patent Document 4). These methods are all achieved only when a PVA-based polymer having a low degree of saponification is used, and they are extremely useful from the viewpoint of imparting low-temperature water solubility to the resulting fiber. However, the difficulty of these methods is that the PVA polymers with low saponification degree used in them have low crystallinity, so the fibers made from them also have low crystallinity, and they cannot have practical applications. Necessary 200536968 mechanical properties. Another problem for them is that a part of the prepared fiber may be dissolved in the steps of coagulation or extraction, and thus the fiber agglomerates. In other words, from the viewpoint of their processability, this type of PVA-based polymer is not satisfactory, so we expect that it can be further improved. In addition, the non-woven fabrics formed from these have excellent low temperature solubility, but their mechanical properties are not good, so their practical applicability is limited. On the other hand, when a PVA-based polymer having a high degree of saponification and a high degree of polymerization is used, the degree of crystallinity of the obtained fiber may increase, so it can achieve excellent mechanical properties such as tensile strength, but the fiber The water-dissolving temperature is 100 ° C or more, which means that the low-temperature water-solubility of the fiber is not satisfactory. A method for improving the water solubility of fibers formed from these PVA-based polymers can be achieved by, for example, greatly reducing the elongation temperature and elongation ratio to retard the orientation crystallization of the obtained fibers. However, the degree of crystallinity of the fibers produced according to this method is of course reduced, and the mechanical properties of the fibers are impaired, etc., so this method is problematic in this respect. Another method for producing PVA-based fibers having a high degree of saponification and a high degree of polymerization of PVA-based polymer Φ is also proposed, which includes in its molecule a reaction with a hydroxyl group present in a molecule of a PVA-based polymer The atomic group modifier is added to the solvent of the dope (forms a fiber solution), thereby giving the obtained PVA-based fiber various properties such as water solubility (see, for example, Patent Document 5). However, according to the method disclosed in the invention patent document 5, due to the polymer's excessive reaction at the stage of the stock solution, the crystallinity of the fiber is reduced, resulting in the water of the produced fiber 200536968. The solubility is not satisfactory, and In addition, mechanical properties such as tensile strength of the fibers are reduced. Another problem with this method is that the recovery system will be contaminated with unreacted materials, and this requires some specific treatment methods and steps to recover these. In addition, in the field of a typical chemical-lace base fabric and a water-soluble non-woven fabric formed of water-soluble PVA-based fibers, it has hitherto required those that can be dissolved in water at 80 ° C or higher, that is, " High-temperature dissolving fabrics ". In recent years, market demand has diversified. In addition to high-temperature dissolvable fabrics, it is also recently expected to require other water that can dissolve at 40 to 80 ° C (that is, dissolve at moderate temperature), or water at about room temperature. Etc., which is "low temperature dissolving fabric". For example, in the case of fine pattern embroidery, the increase in beating (count) density makes it difficult to remove the solvent after embroidery, while in the case of advanced embroidery using thin materials such as silk or acetate, the thermal stability of the material is low. . For these reasons, it is desired to develop a non-woven fabric formed using fibers that can be dissolved at a lower temperature. On the other hand, water-soluble non-woven fabrics are expected to have both excellent mechanical properties such as strength and elastic modulus, in order to prevent troubles such as pattern deviation and breakage of non-woven fabrics during high-tension embroidery processing. For the purpose of developing a non-woven fabric using fibers that can be dissolved at a relatively low temperature, a non-woven fabric formed of PVA-based fibers having a low degree of saponification has been proposed (for example, see Patent Document 6). However, because it is a PVA-based polymer with a low degree of saponification, the degree of crystallinity of the obtained fibers cannot be improved. As a result, although the non-woven fabrics formed from the fibers have excellent low-temperature solubility, they cannot have excellent mechanical properties. Therefore, their practical application of 200536968 is limited. On the other hand, for the purpose of improving the mechanical properties, a fiber made of a PVA-based polymer having a high degree of saponification and a high degree of polymerization can be used to produce a nonwoven fabric as desired. In this type of nonwoven fabric, since the degree of crystallinity of the constituent fibers is high, a nonwoven fabric having sufficient mechanical properties such as tensile strength can be obtained. However, the water-dissolving temperature of this type of non-woven fabric is above 120 ° C, which means that the non-woven fabric cannot meet the requirements of low-temperature water solubility. In order to improve the water solubility of fibers formed from this type of PVA-based polymer, for example, the elongation temperature and elongation ratio can be greatly reduced to prevent the orientation crystallization of the obtained fibers. However, the degree of crystallinity of the fiber produced according to this method is of course lowered, so that there is a problem that the mechanical properties of the nonwoven fabric composed of the fiber are degraded. [Invention Patent Document 1] JP-A No. 3-1 99408 [Invention Patent Document 2] JP-A No. 53-045424 [Invention Patent Document 3] JP-A No. 5 -08 65 03 [Invention Patent Document 4] Japanese Patent Application Laid-Open No. 7-04201 9 [Invention Patent Document 5] Japanese Patent Application Laid-Open No. 2000 · 1 3 643〇 Φ [Invention Patent Document 6] Japanese Patent Application Laid-Open No. 1 1 -2 1 7759 [Summary of the Invention] [Technical Problems to be Solved] As described above, the water solubility of PVA-based fibers has hitherto been controlled by controlling the degree of polymerization and saponification of the PVA-based polymers used and by controlling the Extending conditions, etc. to control can only be given to those. However, any of these methods has a problem in that the degree of crystallinity of the obtained fiber is reduced, and therefore the machine 200536968. The mechanical properties are reduced. In addition, from the standpoint of processability and production costs, these methods have other problems. Therefore, we are looking forward to the development of inexpensive water-soluble PVA-based fibers that have both excellent water-solubility and excellent mechanical properties such as tensile strength, as well as excellent processability, and water-soluble nonwoven fabrics composed of these. [Technical method to solve the problem] The inventors of the present invention and the like have repeatedly studied intently to obtain the above-mentioned water-soluble PVA-based fiber and the non-woven fabric formed by the same. Specific treatment, in the ordinary spinning step, the ionic group-containing compound is penetrated into the fiber, and the compound is reacted with the fiber in the subsequent steps, so that the original water solubility can not be degraded ' Water-soluble PVA-based fibers that have both excellent mechanical properties and high crystallinity are produced inexpensively, and it has been found that when the water-soluble temperature of the water-soluble nonwoven fabric formed from the fibers and the degree of crystallization of the fabric are used as indicators of its mechanical properties In accordance with a specific relationship, a water-soluble non-woven fabric with excellent water solubility and excellent mechanical properties that cannot be achieved by traditional related technologies can be obtained. Based on these findings, we have reached the invention. φ Specifically, the present invention provides a water-soluble PVA-based fiber, which is characterized by reacting with 0.01 to 5 mol% of an ionic group-containing compound, and the degree of crystallinity Xcf (%) of the fiber and the dissolution temperature Wtb ( ° C) The relationship between the following conditions (I):

Wtb &lt; 2.50 · Xcf-70 (I) where 30% $ xcf $ 80%. In addition, in the water-soluble PVA-based fiber of the present invention as described above, it is preferred that the radical-containing compound containing -10-200536968 ions is a glyoxalic acid or a neutralized product of ethanoic acid. In addition, the present invention also provides a method for producing the water-soluble PVA-based fiber, which includes dissolving a PVA-based polymer having a polymerization degree of 1,000 to 4,000 and a degree of halogenation of 88 mol% or more. The spinning dope prepared in an organic solvent is spun in a wet or dry-wet spinning mode into a coagulation bath mainly composed of an organic solvent having a coagulation ability for a polymer, and then the obtained The fiber is passed through an extraction bath composed of 1 to 50 g / 1 of an ionic group-containing compound dissolved therein, thereby allowing the compound to penetrate into the fiber, and then reacting in any step of drying, stretching, or heat treatment to convert the fiber The compound is introduced into the fiber, and the fiber is stretched to a total stretch ratio of 3 times or more in all the steps. In addition, the present invention also provides a water-soluble non-woven fabric, which is characterized by being composed of the above-mentioned water-soluble PVA-based fibers, and the relationship between the degree of crystallinity XCW (%) of the non-woven fabric and the solution temperature SP (° C) in water is as follows Conditions shown in formula (II): SP &lt; 2.50 · Xcw-50 (II) In the formula, 30% S Xcw ^ 65%. Moreover, in the above water-soluble nonwoven fabric of the present invention, the relationship between the elastic modulus M (N / 5 0 mm) of the nonwoven fabric and the solution temperature SP (° C) in water meets the condition shown in the following formula (III): SP &lt; 1.60 Μ-22 (III) where 30 N / 50 mm $ MS 8 0 N / 5 0 mm. [Effect of the Invention] -11-200536968. According to the present invention, a water-soluble PVA-based fiber having excellent mechanical properties such as water-solubility and tensile strength can be provided, and it cannot be achieved by conventional techniques. The water-soluble PVA-based fibers of the present invention can be produced in any ordinary spinning and drawing process, do not require any specific steps, and they can be produced inexpensively. The water solubility of the water-soluble PVA-based fibers of the present invention can be controlled in any way we want, and when the water-soluble temperature and crystallinity of the water-soluble non-woven fabric formed by the fibers are used as indicators of its mechanical properties, When the specific relationship is met, the water-soluble non-woven fabric has both excellent water-solubility characteristics and excellent mechanical characteristics, and it is the one that cannot be achieved by traditional technology. Therefore, the non-woven fabric has many uses, for example, it can be applied to a base fabric for a typical chemical burnt lace. [Best Mode for Carrying Out the Invention] The present invention will be specifically described below. If the mechanical properties, dimensional stability, water-solubility characteristics, etc. of the obtained fiber are considered, the polymerization degree of the PVA polymer used in the present invention is preferably an average polymerization calculated from the viscosity of its 30 ° C aqueous solution. The degree is 1,000 ~ 4,000. When PVA-based polymers with an average degree of polymerization of more than 4,000 are used, the fibers obtained may have excellent mechanical properties, but when dissolved, the fibers will shrink significantly, causing their water solubility characteristics to deteriorate. In addition, when a PVA polymer having an average degree of polymerization of less than 1,000 is used, the crystallinity of the obtained fiber is low, resulting in poor mechanical properties of the fiber, and in addition, the fiber is coagulated, for example In the manufacturing process of extraction or extraction, the polymer may be dissolved out, thereby causing agglomeration of the fibers. Therefore, the average degree of polymerization of the PVA-based polymer used here is more preferably 1,500 to 3,500. • 12- 200536968 The degree of tritium of the PVA polymer used in the present invention is not particularly limited, but from the viewpoint of the crystallinity and water-solubility characteristics of the fiber obtained, it is preferably 88 mol %the above. When using a PVA polymer having a degree of hydration of less than 88 mol%, the crystallinity of the obtained fiber may be greatly reduced. Therefore, although it is favorable for imparting low-temperature water solubility to the fiber, It is not conducive to the mechanical properties, processability and production costs of the fiber. The PVA-based polymer used to form the fiber of the present invention is not particularly limited as long as it is a vinyl alcohol unit as a main component. The polymer may contain any other constituent units such as ethylene, vinyl acetate, itaconic acid, vinylamine, acrylamide, trimethyl vinyl acetate, maleic anhydride, and a sulfonic acid-containing vinyl compound, as necessary, As long as the effect of the present invention is not impaired. However, in order to obtain the object fiber of the present invention, it is preferable to use a PVA-based polymer containing at least 88 mol% of vinyl alcohol units. Of course, if the effect of the present invention is not impaired, the polymer may also contain various additives such as an antioxidant, an antifreeze, a pH adjuster, a concealing agent, a colorant, an oil agent and the like according to the purpose of the present invention. It is important for the water-soluble PVA-based fiber of the present invention to introduce the compound into the fiber by infiltrating the ionic group-containing compound into the fiber at the fiber's precursor stage, and then reacting the fiber with the compound in a subsequent step. Made in China. The water-solubility characteristics of the water-soluble PVA-based fibers of the present invention obtained in this way are expressed by the temperature at which the fibers are soluble, and as described later, this is based on the type of PVA-based polymer and the type of ionic group-containing compound. 2. The reactivity of the compound with the PVA polymer and the ionic groups in the compound 200536968, neutralization degree and control over a wide temperature range. The ionic group-containing compound used in the present invention may be any one capable of reacting with a hydroxyl group in a PVA-based polymer, and is not particularly limited, and includes, for example, aldehydes, epoxy-based, carboxylic acid-based, Isocyanates, silanols, etc. The ionic group is also not particularly limited, and it may be any residual acid, sulfonic acid, or a partially or completely neutralized derivative thereof. From the standpoint of availability, of course, carboxylic acids and their neutralized derivatives are preferred; in particular, if the fiber is to be rendered water soluble at a lower temperature, it is preferred to use metal-neutralized Compounds of carboxylic acid residues. Among these, from the viewpoint of their reactivity with fibers, control of water solubility, and mechanical properties, among them, glyoxylic acid and its metal-neutralizers are particularly applicable. For example, when glyoxylic acid is reacted and introduced into a PVA-based polymer, a carboxylic acid residue can be introduced into the molecular chain of PVA. The carboxylic acid anions have a large steric hindrance and they are mutually exclusive. The molecular chain network of a polymer having these carboxylic acid anions introduced therein is expanded, with the result that the polymer may more easily absorb water. Therefore, the obtained polymer may have a high water absorption rate and be more easily soluble in water at a low temperature. When the carboxylic acid site introduced into the polymer molecular chain is neutralized with a metal having a high degree of ionization, such as sodium, the carboxylic acid anion can be formed more quickly, and the water absorption rate of the polymer can be further increased, with the result that Fibers formed from polymers are more soluble in water at lower temperatures. The metal that can be used to neutralize the ionic group is not particularly limited, and for example, it includes sodium, calcium, and magnesium; preferably, it has a large ionization tendency such as sodium. The method for neutralizing the group is not particularly limited 'and may be any conventional method. -14- 200536968 For example, a carboxylic acid group-containing compound is dissolved in an extraction solvent, and sodium hydroxide can be added thereto to neutralize the carboxylic acid residue with sodium ions. Depending on the amount of metal ions that will be added to the system, the degree of neutrality in the compound can be controlled. It is necessary for the water-soluble PVA-based fiber of the present invention to react with the above-mentioned ionic group-containing compound in an amount of 0.001 to 5 mol%. If the degree of reactivity between the water-soluble PVA-based fibers of the present invention and the ionic group-containing compound is less than 0.001 mole%, the objective water-soluble fibers of the present invention cannot be obtained; but if it is more than 5 mole%, The degree of crystallinity of the fibers may be low, which may cause problems such as reduction of the mechanical properties of the fibers produced, or a large shrinkage when the fibers are dissolved. The reactivity with the compound is preferably from 0.05 to 4 mole%, more preferably from 0.08 to 3 mole%. The degree of reactivity between the water-soluble PVA-based fiber of the present invention and the ionic group-containing compound can be measured by a method described later. Furthermore, another significant feature of the water-soluble PVA-based fibers of the present invention is that although the water-soluble fibers are soluble in water, they have excellent mechanical properties such as tensile strength and the like. In particular, it is important that the water-soluble PVA-based fiber of the present invention conforms to the relationship represented by the following formula (I), where wtb (° C ·) represents the fiber's dissolution temperature in water, and Xcf (%) represents the fiber The degree of crystallinity is used as an indicator to improve the mechanical properties of the fiber:

Wtb &lt; 2.50 · Xcf 70 (I) where 30% S Xcf S 80%. So far, it is based on controlling the degree of polymerization and saponification of the polymers used to form the fibers, and the elongation conditions of the resulting fibers to control the water solubility of the water-soluble fibers. The crystallization of the fibers is sacrificed, so it cannot be obtained Water-soluble fiber with excellent mechanical properties. FIG. 1 shows water-soluble PVA-based fibers of the present invention, and water-soluble PVA-based fibers disclosed in Japanese Patent Laid-Open Nos. 7-420 1 9 and 7-90714, and current commercial products. The water-soluble fibers ("Solvron" made by Nitivy) are shown in the first grade, respectively, and the relationship between the water solubility temperature and the crystallinity of each fiber is shown. The "Solvron" series includes: SS, SU, SX, and SL, and are represented by white circles; In addition, disclosed in Japanese Patent Publication No. 7-42019 and Japanese Patent Publication No. 7-9071 4 The water-soluble fibers are represented by white squares; and the samples of the water-soluble H-soluble PVA-based fibers (Examples) of the present invention are represented by black dots; and the comparative examples are represented by black squares. As shown in Fig. 1, the water-soluble fibers of "Solvron" and the water-soluble fibers disclosed in JP 7-4201 9 and JP 7-9 07 1 4 are in the water of the fibers. The relationship between the dissolution temperature Wtb (° C) and the degree of crystallinity Xcf (%) is almost linear, and the relationship between them is shown in the following formula (IV):

Wtb &gt; 2.50 · Xc-58 (IV) φ where 30% ^ Xc ^ 80%. The details are explained in the examples. In short, the water-soluble PVA-based fibers of the present invention are all in the range of the formula (I) (in the hatched area in the figure). Compared with the conventional water-soluble fiber, the water-soluble PVA-based fiber of the present invention has a higher degree of crystallization, that is, the water-soluble PVA-based fiber of the present invention has excellent mechanical properties. When the degree of crystallization Xcf is less than 30%, the mechanical properties of the fiber are not good; when it is higher than 80%, the Wtb is 120_16-200536968 ° c or more. Therefore, these systems cannot meet the purpose of the present invention. The "dissolution temperature in water Wtb (° c)" and "degree of crystallinity Xcf (%)" of the fiber in the present invention are measured according to a method described later. Although the water-soluble PVA-based fibers of the present invention are soluble in water, the reason why they have a high degree of crystallinity is unclear, but the inventors speculate that they are as follows. The introduction of an ionic group-containing compound into the fiber is expected to lower the melting point of the fiber more or less, and the substantial extension conditions of the fiber containing the compound may be different from those of the fiber without the compound. Therefore, in the present invention, it is speculated that the fiber should be extended at a temperature as close as possible to the melting point of the fiber. In particular, in the present invention, it is presumed that the fiber can be extended in a state of high molecular mobility of the fiber, whereby the orientation crystallization of the fiber can be promoted, and the obtained fiber can have a high degree of crystallinity. The fineness of the fiber obtained in the present invention is not particularly limited, and a fiber having a wide range such as 0.1 to 10,000 dtex, preferably 1 to 100 dtex can be used. The fineness of the fiber can be appropriately controlled by changing the spinning nozzle diameter and the elongation ratio. Next, a method for producing the water-soluble PVA-based fiber of the present invention is described below. In the present invention, the PV A-based polymer is dissolved in water or an organic solvent to prepare a spinning dope, and this is spun into fibers according to a method described later. Therefore, it is possible to efficiently and inexpensively produce a PVA-based fiber having high crystallinity, excellent mechanical properties, and excellent water solubility. Solvents used to form the spinning dope include polar solvents such as dimethylmethylene (hereinafter referred to as "DMSO"), dimethylacetamide, dimethylformamide, and N-methylpyridine 200536968. Pyridone, etc .; or polyhydric alcohols, such as glycerol, ethylene glycol, etc .; and mixtures of these solvents and swelling metal salts, such as rhodanate, lithium chloride, calcium chloride, chlorine Zinc and the like; and these solvents, or a mixture of these solvents and water, and the like. From the viewpoints of polymer processability such as fiber and solvent recovery, water and DMSO are most suitable among these. The polymer concentration in the spinning dope varies depending on the composition, the degree of polymerization, and the solvent, but it is preferably in the range of 8 to 40% by mass. The temperature of the spinning dope at the time of spinning is preferably within a range where the spinning dope is neither decomposed nor colored; specifically, the temperature is preferably between 50 and 150 ° C. Thai spinning dope is spun through the spinning nozzle in wet spinning or dry-wet spinning mode into a coagulation bath with coagulation energy for PVA polymer. "Wet spinning" is a method of spinning the spinning dope through the spinning nozzle directly into the coagulation bath; and "dry-wet spinning" is the spinning dope when spinning through the spinning nozzle to enter any distance I want Air or inert gas, and then introduced into the coagulation bath. The coagulation bath used in the present invention differs between those in which the solvent in the spinning dope is an organic solvent and those in which the solvent is water. From the viewpoint of the strength and strength of the obtained fiber, for the spinning dope using an organic solvent, the coagulation bath is preferably a mixture containing a solvent for the coagulation bath and a solvent for the spinning dope. The coagulation solvent is not particularly limited, and it may be an organic solvent having coagulation energy for PVA polymers, such as alcohols such as methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, and methyl isopropyl alcohol. Ketones such as butyl ketone. From the viewpoint of low-corrosive uranium properties and solvent recovery, a combination containing methanol and DMS0 is preferred. On the other hand, when the spinning dope is an -18-200536968 aqueous solution, both of the coagulating solvents constituting the coagulation bath may be an inorganic salt (such as crystalline sodium sulfate, Sodium chloride, sodium carbonate, etc.). Next, the solidified strand is guided through an extraction bath for removing a solvent for spinning dope from the strand. In order to suppress the agglomeration between the fibers during drying and to improve the mechanical characteristics of the fibers, it is preferable to perform wet-drawing while guiding the fibers through the extraction bath. From the viewpoint of processability and productivity of the fiber, the wet-stretching ratio is preferably 2 to 6 times. The extraction solvent may be a coagulation solvent used alone or a mixture containing a spinning dope solvent and a coagulation solvent in combination. After wet-drawing, the fibers can be dried and further drawn into PVA-based fibers for the purpose of the invention. To obtain the fibers of the present invention, they can be guided through an extraction bath containing an ionic group-containing compound dissolved therein, thereby infiltrating the compound into the fibers. In this case, from the viewpoint of uniformly penetrating the ionic group-containing compound into the fibers, it is preferable that the fibers are swelled by the extraction solvent in the extraction bath. For this purpose, the extraction solvent is preferably an alcohol such as methanol, or water. In particular, the fibers have been completely crystallized during the spinning step, and then the ionic group-containing compound is infiltrated into the fibers that have been swollen by the extraction solvent in the extraction bath, and then the fibers are dried, drawn, and heat-treated. In these subsequent steps, the compound that has penetrated into the fiber reacts with the fiber and is introduced into the fiber. As a result, a PVA-based fiber having excellent mechanical properties such as tensile strength and excellent water solubility can be obtained without substantially reducing the fiber elongation ratio. On the other hand, when a modifier containing an atomic group (such as an aldehyde group or an ester group) that easily reacts with the hydroxyl group of the PVA polymer 200536968 ·, is added to the spinning dope, the reaction may be This phase begins and continues, with the result that the crystallization of the fibers may be retarded during the coagulation step, and the extensibility of the fibers may be reduced. Therefore, the obtained fiber may have a low degree of crystallinity and poor mechanical properties. Similarly to this, when the ionic group-containing compound is reacted with a PVA-based polymer in advance and the obtained PVA-based polymer is used as a raw material to manufacture the fiber, the degree of crystallinity of the obtained fiber is also low, and the mechanical characteristics of the fiber are also Not good. In addition, when the compound is applied to the fiber in a roller contact mode after the fiber has been stretched or heat-treated, a sufficient amount of the compound cannot be imparted to the fiber, and in addition, the compound cannot penetrate the fiber uniformly. Medium, and the reproducibility of the processing is not good. Therefore, as described above, it is preferable that the fibers penetrate into the PVA-based fibers at the same time when the fibers are swollen with the extraction solvent in the extraction bath. As described above, the water-dissolving temperature of the PVA-based fiber of the present invention can be appropriately controlled by changing the introduction amount of the ionic group-containing compound. The addition amount of the ion-containing compound to the extraction bath is appropriately set depending on the water-solubility characteristics required for the fiber to be produced. The addition amount is preferably, for example, in the range of 1 to 50 g / 1. If the added amount is less than 1 g / 1, it is not appropriate, because the fiber cannot have the water-solubility characteristics required for the purpose of the present invention, and if it is greater than 50 g / 1, it is also inappropriate. Because the reaction may proceed quickly and the crystallinity of the fiber is reduced, the mechanical and physical characteristics of the fiber are deteriorated and the fiber may shrink in water. The added amount is more preferably 2 to 30 g / I. The -20-20200536968 compound which is introduced into the fiber through a spinning step including coagulation and extraction is reacted with the fiber by heating in any step of drying, stretching and heat treatment after spinning, whereby The water-soluble PVA-based fiber of the present invention was obtained. During drying, stretching or heat treatment, the temperature necessary to promote the reaction is not particularly limited, but if it is considered that the reaction must be performed simultaneously with the stretching treatment used to show the mechanical properties of the fiber, it is preferably 100 ~ 240 ° C. If the temperature is lower than 100 ° C, the reaction may not be easy, and the resulting fiber may be whitened, resulting in poor mechanical and physical characteristics of the fiber. On the other hand, if the temperature is higher than 240 ° C, the fiber produced may be partially melted, which is disadvantageous because the mechanical and physical properties of the fiber repair may be reduced. The temperature is more preferably in the range of 120 to 220 ° C. The total elongation of the water-soluble PVA-based fiber of the present invention is preferably 3 times or more. If the elongation ratio is less than 3 times, the mechanical properties of the resulting fiber may be impaired. The "elongation ratio" as used herein means the product of the wet-elongation ratio in the coagulation bath before drying and the elongation ratio after drying. For example, if the wet stretch ratio is 3 times and the subsequent stretch ratio is 2 times, the total stretch ratio is 6 times. _ The water-soluble PVA-based fibers of the present invention can be used in the form of, for example, cut fibers, long fibers, short-fiber twisted yarns, ropes, ropes, and fibrils. If desired, the fibers can be made into a non-woven, woven or knitted fabric. From the viewpoint of the use required for water solubility, the fiber is more preferably used as a non-woven fabric, for example, as a base fabric for chemical burnt lace. The relationship between the water-soluble non-woven fabric made of the above-mentioned water-soluble PV A-based fibers, the dissolution temperature SP (° C) in water of the non-woven fabric, and the mechanical properties of the non-woven fabric refer to the degree of crystallinity Xcw (%) of the standard of 21-200536968. When it conforms to the following formula (II), although it has excellent water solubility, it also has excellent mechanical properties such as tensile strength and elastic modulus. SP &lt; 2.50 · Xcw-50 (II) where 30% ^ XCW ^ 65%. As described above, the water-dissolving properties and mechanical properties of the nonwoven fabric have been controlled by changing the formulation of the water-soluble PVA-based fibers to be used so far. For example, when we expect to obtain water-soluble nonwoven fabrics with excellent low-temperature solubility, we use PVA-based polymers with a low degree of polymerization or a low degree of saponification as raw materials, or use PVA prepared by controlling the elongation conditions Department of fiber. In particular, the fibers to be used in the manufacture of nonwoven fabrics impart water-solubility properties by reducing their crystallinity. However, according to the conventional method, the obtained fiber has a low degree of crystallinity, and therefore the water-soluble nonwoven fabric manufactured from the fiber may not have satisfactory mechanical properties, although its water-solubility characteristics may be excellent. FIG. 2 shows a water-soluble nonwoven fabric of the present invention, a nonwoven fabric made of water-soluble PVA-based fibers disclosed in Japanese Patent Laid-Open Nos. 7-4201 9 and 7-907 14 (Comparative Example) ), And the relationship between the temperature of dissolution in water and the degree of crystallization between sheets made of water-soluble fiber [Nitivy (So Wron) made by Nitivy (commercially available)] that are currently commercially available. The “Solvron” series includes SS, SU, SX, and SL, and these sheet samples are indicated by white circles. The non-woven fabric formed by the water-soluble fibers disclosed in Japanese Patent Laid-Open Publication No. 7-42019 and Japanese Patent Laid-Open Publication No. 7-90714 is represented by a white square. The trial of the water-soluble PVA-based fiber of the present invention (200536968) is shown by black dots. As shown in Fig. 2, the sheet of "Solvron" and the water-soluble non-woven fabrics disclosed in JP-A No. 7_42019 and JP-A No. 7-9 0 7 1 4 have a water solubility temperature SP (° C) It has an almost linear relationship with the degree of crystallinity Xcw (° C), and the relationship is shown by the following formula (V): SP &gt; 2.50 · Xcw 39 (y) In the formula, 30% ^ Xcw ^ 65 %. As shown in FIG. 2, all the water-soluble nonwoven fabrics of the present invention fall within the range of the formula (π) (the oblique area in the figure). Compared with the traditional water-soluble non-woven fabric, it is characterized by a higher degree of crystallinity of the water-soluble non-woven fabric of the present invention, although its dissolution temperature in water is the same. Among them, if the degree of crystallization Xcw is less than 30%, the mechanical properties of the nonwoven fabric are not good. For example, when the nonwoven fabric is used as a base fabric for chemical firing, the nonwoven fabric may occur during embroidery Damage or pattern deviation. Therefore, non-woven fabrics with such poor mechanical characteristics will have limited practical applicability. On the other hand, when the crystallization degree Xcw exceeds 65%, the dissolution temperature SP of the fabric will be 120 ° C or more. If so, when embroidering fine patterns, the beating Φ density may increase, and the solvent is not easy to remove after embroidery. In addition, when using advanced embroidery of thin materials such as silk or acetate, the thermal stability of the material is not good. Therefore, the material of silk or acetate may be deteriorated. Due to these problems, the object of the present invention will be difficult to achieve. In addition, the "dissolution temperature in water SP (° C)" and the "degree of crystallization Xcw (%)" mentioned in the present invention are measured according to a method described later. Fig. 3 shows the relationship between the elastic modulus of the non-woven fabric used as shown in Fig. -23- 200536968 (N / 50 mm) and the solution temperature SP (t :) in water. As shown in FIG. 3, the elastic modulus M of Solvron or a water-soluble non-woven fabric composed of fibers disclosed in JP 7-42019 and JP 7-90714 is a water-soluble nonwoven fabric. The dissolution temperature SP has a nearly linear relationship, and its relationship is shown in the following formula (VI): SP &gt; 1.60 Μ-4.0 (VI) where 30 N / 50 mm SMS 80 N / 50 mm As shown in FIG. 3, the water-soluble nonwoven fabric of the present invention is all within the range of formula (III) (slashed area in the figure), which is characterized in that the water-soluble PVA fabric of the present invention is compared with the conventional water-soluble nonwoven fabric. Its modulus of elasticity is high, even if its dissolution temperature in water is the same. As shown in Fig. 2, this may be due to the high crystallinity of the nonwoven fabric of the present invention. If the elastic modulus M is less than 30 N / 5 0 mm, for example, when the fabric is used as a base fabric for chemical burning lace, it may be damaged during embroidery, or a pattern may occur during embroidery processing. Deviation, so the practical applicability of non-woven fabrics will be limited. In addition, when the elastic modulus M is higher than 80 N / 5 0 mm, the dissolution temperature SP of the fabric is inevitably increased to 110 ° C or more. If this is the case, when slender-patterned embroidery, the beating density may increase, and the solvent is not easy to remove after embroidery. In addition, when using advanced embroidery of thin and light materials such as silk or acetate, the heat of the material is stable. Poor properties, so silk or acetate materials may be deteriorated. Because of these problems, the object of the present invention will be difficult to achieve. In addition, the "elastic modulus M (N / 5 0 mm)" mentioned in this invention is measured according to the method mentioned later. The manufacturing method of the water-soluble non-woven fabric of the present invention is not particularly limited, and any of the conventional and conventional methods can be used as -24-200536968. Specifically, for example, needle piercing method, embossing method, foam bonding method, heating method of thermally fused fiber mixture (embossing, hot air heating, molding), adhesive bonding method, water jet method , Melt blown method or spinning and bonding methods, and the non-woven fabrics made from them can be laminated, or these methods can be combined in any way we want. In any case, any desired method is appropriately selected depending on the quality of the nonwoven product to be manufactured. For example, the tow of the water-soluble PV A-based fibers prepared in the above manner is opened by utilizing the repulsive action of frictional charging; or the short fibers that are crimped or cut are combed and opened to form a fiber network, Then use a hot embossing roller with a bonding area ratio of 3 to 50%, at a temperature of 20 to 100 ° C lower than the melting point of the water-soluble PVA-based fibers constituting the fiber web, and at a linearity of 3 to 100 kg / cm A heat bonding process is applied under pressure to obtain a water-soluble nonwoven fabric. In this case, if the bonding ratio of the hot embossing roller is less than 3%, the bonding area will be small and the mechanical properties of the nonwoven fabric will be poor; but if it is greater than 50%, the bonding will be due to bonding. The area will become larger and the feel of the non-woven fabric will become harder. Besides, the produced non-woven fabric is prone to wrinkles. The adhesion ratio of the embossing roller is preferably 5 to 40%, and more preferably 10 to 30% from the viewpoint of the mechanical characteristics and feel of the nonwoven fabric to be produced. When the thermal bonding temperature is higher than (Tm-20 ° C), where Tm is the melting point of the water-soluble PVA fibers used to form the fiber web, the adhesion can be improved and the non-woven fabric has excellent mechanical properties, but The water solubility of the fabric may deteriorate. If the bonding temperature is lower than (Tm-100 ° C), the thermal bonding is not satisfactory and the non-woven fabric produced is not good. Therefore, the thermal bonding temperature is preferably between -25-200536968 (Tm-20 ° C) and (Tm-100 ° C). When the bonding ratio is high, it is preferable to decrease the thermal bonding temperature; but on the contrary, when the ratio is low, it is preferable to increase the thermal bonding temperature. The "heat bonding temperature" mentioned in this article refers to the temperature of the non-woven fabric, not the temperature of the embossing roller used. When the speed of the embossing roll is low, the temperature of the non-woven fabric itself may be almost the same as the temperature of the roll; however, if the embossing roll rotates at a high speed, the heat transfer may be insufficient and the temperature of the non-woven fabric may decrease. If the linear pressure is less than 3 kg / cm, the cross section of the fiber in the heat-bonding zone cannot be satisfactorily flattened, and the bonding area is not large, so the strength of the non-woven fabric will be insufficient. If the thermal bonding is achieved under a linear pressure of more than 100 kg / cm, the fiber itself may be damaged due to the bonding industry, and the obtained fabric may crack and perforate near the embossing point, resulting in mechanical properties of the fabric deterioration. From the viewpoint of the mechanical characteristics of the nonwoven fabric to be produced, the linear pressure is preferably 10 to 80 kg / cm, and more preferably 15 to 40 kg / cm. If the bonding ratio is low or the bonding temperature is low, a high linear pressure is required; however, from the viewpoint of the comprehensive characteristics of the produced nonwoven fabric, the linear pressure is preferably low. In this nonwoven fabric, the content of the water-soluble PVA-based fiber of the present invention is preferably 5 to 100% by mass. If the content is less than 5% by mass, it may be difficult to use it for applications requiring water solubility. Since the water-soluble PVA-based fiber of the present invention has both excellent fiber characteristics such as thermal adhesiveness and excellent strength and flexibility, it can be embossed or needled with 100% by mass of the water-soluble PVA-based fiber of the present invention. Processed into non-woven fabrics. However, depending on the quality and cost of the intended product, the water-soluble PVA-based fibers of the present invention can be combined with any other fibers to use 200536968, such as natural fibers that can be combined with pulp or cotton; or CuCupra Recycled fibers such as acetate; semi-synthetic fibers such as acetate or Promix; for example, polyester fibers, acrylic fibers, polyamide fibers (nylon, aromatic polyamide, etc.), Synthetic fibers such as water-insoluble PVA-based fibers are mixed or laminated. If necessary, the non-woven fabric formed of the water-soluble PVA-based fiber of the present invention may form a composite with any other material such as a film, a metal, a resin, and the like. The pattern (pattern structure) of the water-soluble non-woven fabric of the present invention is not particularly limited because the required performance of the fabric varies depending on its use. The square diamond-shaped zigzag lattice pattern, deformed quadrangular shape can be appropriately selected according to the use and purpose of the fabric. Pattern, dot pattern, woven eye pattern, etc. [Embodiments] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, the reactivity of the ionic compounds in the fibers, the temperature at which the fibers dissolve in water, the tensile strength of the fibers, the temperature at which the nonwovens dissolve in water, the temperature at which the fibers dissolve in water, the crystallinity of the nonwovens and fibers, The elastic modulus of the nonwoven fabric is measured by the method described below. [Reaction degree of ionic compounds in fibers, mole%] "Reaction degree" is measured using a nuclear magnetic resonance (NMR) device manufactured by Japan Electronics Corporation. The PVA fiber to be analyzed is dissolved in a DMSO solution having a solution temperature of 50 to 140 ° C, and then measured using 13C-NMR. The reactivity is based on the peaks assigned to the structure (acetal) formed by the reaction ( Chemical shift = 100 ppm) was calculated based on the area ratio of the peak of CH2 group in PVA 200536968. [Crystallinity (Xcf, Xcw),% of fibers and non-woven fabrics] The total melting enthalpy of the sample to be analyzed (Δ 试. ^) Was measured using a Pyris-1 type micro scanning calorimeter manufactured by Perkin-Elmer. ). Regarding the measurement conditions, the heating rate was 80 ° C / min, and the mass crystallinity of the sample was calculated according to the following formula. In addition, indium and lead are used as reference materials to correct the melting point and heat of melting.

Xcf, Xcw (%) = ΔH〇bs / Δ Heal x 10 0 In the formula, ΔH. ^: Measured total heat of fusion (J / g), △ Heal: Fully crystallized heat of fusion (174.5 J / g). [Dissolution temperature (Wtb) in fiber in water, ° C] A predetermined load (2 mg / dtex) is applied to the fiber sample to be analyzed, and the sample is suspended in ice water whose temperature is maintained at 3 ° C. This was heated at a heating rate of 2 cycles per minute, and the relationship between the temperature of the water between which the sample was broken and its load dropped and the shrinkage of the sample was measured. Read the temperature at which the load drops, and this is the melting temperature in water of the sample fiber, Wtb. [Fiber strength, cN / dtex] According to JIS L1 013, a yarn sample having a length of 20 cm was humidity-adjusted in advance, and the measurement was performed under conditions of an initial load of 0.25 cN / dtex and a drawing rate of 50% / min. And use the average η of η = 20. The fiber fineness (dtex) is obtained according to the mass method. [Dissolution temperature (SP) in water of non-woven fabric, t] Cut three pieces into square non-woven fabrics each having a size of 2 cm X 2 cm 200536968 and put in 400 cc of water at a heating rate of 3 ° C / min and a stirring rate of , Heating at 2 80 rpm. The temperature at which the fiber was completely dissolved was measured, and the temperature at which the sample was dissolved in water. [Elastic modulus (M) of non-woven fabric, N / 50 mm] The non-woven fabric was cut in two directions perpendicular to each other into two rectangular poem-shaped specimens each having a width of 5 cm and a length of 15 cm. The testing machine and automatic plotter were used to measure the sample length of 10 cm, the initial load of 0.25 cN / dtex, and the tensile speed of 100% / min. Then, the tensile strength of the sample was extended by 50 mm to 40%. g / cm2 average unit weight of unit area per unit weight. [Example 1] (1) PVA having a viscosity average polymerization degree of 1,700 and a saponification degree of 96.0 mol% was added to DMSO to prepare a DMSO solution having a PVA concentration of 23% by mass, and at 90 ° C is heated and dissolved in a nitrogen atmosphere. The prepared spinning dope was passed through spinning nozzles each having a hole diameter of 0.08 mm and a number of holes of 108, and was spun in a dry-wet spinning mode into a liquid temperature of 5 ° C from methanol / DMSO = 70. / 30 · (by mass) in a coagulation bath. (2) The coagulated yarn thus prepared was immersed in a second bath having the same composition of methanol / DMSO as a coagulation bath. Then a 3-fold wet-extension was performed in a methanol bath at 25 ° C. Next, this was immersed in a methanol bath (extraction bath) containing 10 g / 1 of glyoxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and dissolved therein, and then dried under hot air at 120 ° C to make a textile. Silk yarn. Secondly, the obtained spinning -29- 200536968 raw yarn was stretched in a hot-air stretching furnace at 160 ° C to a total stretching ratio (wet-elongation ratio X hot-air furnace stretching ratio) of 6 times. The performance evaluation results of the fibers produced here are shown in Table 1. (3) The reactivity of glyoxylic acid in the prepared fiber was 0.9 mole%. In addition, the fiber physical properties of the obtained fiber are as follows: the monofilament fineness is 2.0 dtex, the crystallinity of the fiber is Xcf = 38%, the dissolution temperature in water is Wtb = 20 ° C, and the fiber strength is 7.5 cN / dtex. (4) From the above item (3), it can be known that the relationship between the degree of crystallinity Xcf of the fiber and the temperature of dissolution in water Wtb meets the requirements of formula (I), the appearance of the fiber is good, and there are no defects such as gauze, and the fiber The fiber is superior to the conventional water-soluble PVA fiber. (5) The fiber prepared as described above is crimped, cut into short fibers, and then carded to make a fiber web. Then, using an embossing roll with a square rhombic zigzag lattice pattern with a bonding area ratio of 25%, the fiber was set at a temperature of 180 ° C, a speed of 10 m / min, and a linear pressure of 40 kg / cm. The net is heat-embossed. The evaluation results of the non-woven fabrics thus produced are shown in Table 3. (6) The non-woven fabric thus produced has a basis weight of 40 g / cm2, a water solubility temperature SP = 61 ° C, a degree of crystallization Xcw = 45%, and an elastic modulus M = 43 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity XCW of the non-woven fabric conforms to the condition of formula (II); and the relationship between the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric meets the condition of formula (III) , And have both excellent solubility and mechanical properties. 200536968 (7) Further applying embroidery to the non-woven fabric made in item (5) above, as a result, no fibers were cut by embroidery needles, and embroidery cloth with beautiful appearance can be embroidered. [Example 2] (1) Except for using 50% of glyoxylic acid that had been neutralized with sodium hydroxide in the carboxylic acid portion, spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 1. The degree of reactivity of glyoxylic acid in the obtained fibers was 0.8 mol%. In addition, the fiber physical properties of the obtained fiber are as follows: monofilament fineness is 2.1 dtex, fiber crystallinity Xcf = 43%, water dissolution temperature Wtb = 15 ° C, fiber strength is 7.6 cN / dtex, and fiber crystallization The relationship between the degree Xcf and the temperature of dissolution in water Wtb meets the requirements of formula (I). Therefore, the appearance of the fiber is good without defects such as gauze, and the fiber is superior to the conventional water-soluble PVA fiber. (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 3. The prepared nonwoven fabric had a weight per unit area of 42 g / cm2, a solution temperature in water SP = 63 ° C, a degree of crystallization Xcw = 53%, and an elastic modulus M = 45 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric meets the condition of formula (II); and the relationship between the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric meets the condition of formula (III) 200536968 (3) Further applying embroidery to the non-woven fabric made in the above item (2), as a result, there is no fiber cutting caused by the embroidery needle, and the embroidery has a beautiful appearance Embroidered cloth. [Example 3] (1) Except that PVA having a degree of trituration of 88 mol% was used, the fibers were spun and stretched under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 1. The prepared fiber had good appearance and no defects such as gauze. The monofilament fineness was 2.1 φ dtex, the fiber strength was 3.6 cN / dtex, the crystallinity of the fiber was Xcf = 32%, and the dissolution temperature in water was Wtb = 5 ° C. The relationship between the degree of crystallinity Xcf of the fibers and the temperature of dissolution in water Wtb meets the condition of formula (I). (2) Except that the embossing temperature of the fiber obtained in the above item (1) was changed to 140 ° C, a heat embossing treatment was applied under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 3. The prepared non-woven fabric has a weight per unit area of Φ 4 1 g / cm2, a dissolution temperature in water SP = 21 ° C, a degree of crystallization Xcw = 3 2%, and an elastic modulus M = 34 N / 5 0 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric conforms to the condition of formula (II); and the relationship between the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric meets the condition of formula (III) , And have both excellent solubility and mechanical properties. (3) Further apply embroidery to the non-woven fabric made in item (2) above. As a result, there is no fiber cut caused by embroidery needles, and embroidery fabric with beautiful appearance is embroidered. [Example 4] (1) Except that PVA having a halogenation degree of 98 mol% was used, the fibers were spun and stretched under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 1. The obtained fiber had a good appearance and no defects such as gauze. The monofilament fineness was 2.2 dtex, the fiber strength was 6.6 cN / dtex, and the crystallinity of the fiber

Xcf = 49%, water-dissolving temperature Wtb = 62 ° C; and the relationship between the fiber knot · crystallinity Xcf and water-dissolving temperature Wtb meet the requirements of formula (I). (2) Except for the fiber obtained in the above item (1), a heat embossing treatment was applied under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced non-woven fabrics are shown in Table 3. The prepared nonwoven fabric has a weight per unit area of 40 g / cm2, a dissolution temperature SP = 83 ° C, a degree of crystallization Xcw = 60%, and an elastic modulus M = 65 N / 50 mm; the dissolution temperature SP and The relationship between the crystallinity Xcw # of the non-woven fabric conforms to the condition of formula (II); and the relationship between the solution temperature SP of the non-woven fabric in water and the elastic modulus M of the non-woven fabric meets the condition of formula (III); and has excellent solubility And mechanical characteristics. (3) Further embroidering the non-woven fabric made in the above item (2). As a result, there was no fiber cutting caused by the embroidery needle, and an embroidery fabric with beautiful appearance was embroidered. -33- 200536968 [Example 5] Except using PVA with a viscosity average polymerization degree of 1,700, a degree of hydration of 98.0 mol%, an elongation temperature of 200 ° C, and an elongation ratio of 10 times, the rest are the same as In Example 2, spinning and stretching were performed under the same conditions to obtain fibers. The degree of reactivity between the obtained fiber and glyoxylic acid was 0.9 mole%. In addition, the obtained fiber had a good appearance and no defects such as gauze, and the fiber was superior to the conventional water-soluble PVA-based fiber. And the physical properties of the fiber are as follows: The monofilament fineness is 2.0 dtex, the fiber strength is 8.5 cN / dtex, the crystallinity of the fiber is Xcf = 60%, the melting temperature in water is Wtb = 65 ° C, and the crystallinity of the fiber is Xcf # and water The relationship between the dissolution temperature Wtb meets the conditions of the formula (I). [Example 6] (1) A PVA having a viscosity average polymerization degree of 1,700 and a degree of halide of 96.0 mole% was added to water to prepare a PVA aqueous solution having a PVA concentration of 16% by mass, and Dissolve by heating under nitrogen at 90 ° C. The prepared spinning dope was passed through spinning nozzles each having a hole diameter of 0.16 mm and a hole number of 108 holes, and was wet-spun into a coagulation bath composed of a saturated crystalline sodium sulfate aqueous solution. ® (2) The fiber thus prepared is wet-stretched 3 times in water, and then passed through a g / I sodium glyoxylate neutralizer (wherein the ionic group, the carboxylic acid portion has been % Sodium hydroxide plus neutralization) in a water bath (extraction bath), whereby the crystalline sodium sulfate is washed, and the sodium glyoxylate neutralizer penetrates into the inside of the fiber. Thereby, a spinning raw yarn can be obtained. Secondly, the spinning raw yarn was stretched in a hot-air stretching furnace at 1 60 ° C to a total stretching ratio of 6 times. The performance evaluation of the prepared fiber is shown in Table 1. (3) The reactivity of the prepared fiber with glyoxylic acid was 1.0 mole%. In addition, the fiber has a good appearance without defects such as gauze, and the fiber is superior to the conventional water-soluble PVA fiber. In addition, the fiber physical properties of the obtained fiber are as follows: the monofilament fineness is 2.2 dtex, the fiber strength is 7.0 cN / dtex, the crystallinity of the fiber is Xcf = 45%, the dissolution temperature in water is Wtb = 18 ° C, and the crystal of the fiber is The relationship between the degree of chemical conversion Xcf and the dissolution temperature Wtb in water is in accordance with the condition of the formula (I). [Comparative Example 1] (1) Except that no glyoxylic acid was added, spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 2. The obtained fiber had good appearance and no defects such as gauze. However, the monofilament fineness is 2.0 dtex, the crystallinity of the fiber is Xcf = 35%, and the melting temperature in water is Wtb = 30 ° C: The relationship between the crystallinity of the fiber, Xcf, and the melting temperature in water, Wtb, does not meet the formula (I) Conditions, but meet the conditions of formula (IV). (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared non-woven fabric had a weight per unit area of 40 g / cm2, a solution temperature in water SP = 75 ° C, a degree of crystallization Xcw = 42%, and an elastic modulus M = 35 N / 50 mm. The relationship between the temperature of dissolution in water of non-woven fabric and the degree of crystallinity Xcw of non-woven fabric does not meet the requirements of formula (Π), but meets the condition of formula -35- 200536968 (V); The relationship between the elastic modulus μ of the cloth does not meet the conditions of formula (III), but meets the conditions of formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in item (2) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 2] (1) Except that glyoxylic acid was not added, and # PVA having a degree of halide of 88 mol% was used, the spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. Table 2 shows the results of performance evaluation of the obtained fibers. The obtained fiber had good appearance and no defects such as gauze. However, the monofilament fineness was 2.0 dtex, the crystallinity of the fiber was Xcf = 20%, and the melting temperature in water was Wtb = 5 ° C. The relationship between the crystallinity Xcf of the fibers and the temperature of dissolution in water Wtb does not meet the requirements of formula (I), but meets the requirements of formula (IV). (2) Except that the fiber obtained in the above item (1) was set to an embossing temperature of 140 ° C, the rest was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared nonwoven fabric had a weight per unit area of 40 g / cm2, a dissolution temperature SP = 20 ° C, a degree of crystallization Xcw = 27%, and an elastic modulus M = 19 N / 5 0 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric does not meet the requirements of the formula (II), but meets the condition of the formula (V); and -36- 200536968 The relationship between the elastic modulus M and does not meet the conditions of formula (III), but meets the conditions of formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in item (2) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 3] (1) Except that glyoxylic acid was not added, and PVA having an average viscosity of 1,700 # and a degree of halogenation of 98 mol% was used, the rest were performed under the same conditions as in Example 1. Spinning and drawing to make fibers. The performance evaluation results of the obtained fibers are shown in Table 2. The prepared fibers had good appearance and no spot defects. However, the monofilament fineness was 1.9 dtex, the crystallinity of the fiber was Xcf = 44%, and the melting temperature in water was Wtb = 65 ° C. The relationship between the degree of crystallinity Xcf of the fiber and the temperature of dissolution in water Wtb does not meet the requirements of formula (I), but meets the requirements of formula (IV). _ (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared nonwoven fabric had a weight per unit area of 39 g / cm2, a dissolution temperature SP = 93 ° C, a degree of crystallization Xcw = 60%, and an elastic modulus M = 60 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric does not meet the requirements of the formula (Π), but meets the condition of the formula (V) -37- 200536968; The relationship between the elasticity and the modulus M does not meet the requirements of formula (III), but meets the requirements of formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in item (2) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 4] (1) Except that glyoxylic acid was not dissolved in the extraction bath, and it was applied to the stretched fibers (later given to the stretched fibers) in a mode of roller contact Timuga. Then, spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 2. The monofilament fineness of the obtained fiber was 2.5 dtex. The reactivity of glyoxylic acid was 1.1 mole%, and the dissolution temperature Wtb in water was 42 ° C. However, since the glyoxylic acid reacts only on the surface of the fiber, even though the crystallinity Xcf of the fiber is 32%, the fiber strength is only as low as 5.5 cN / dtex. The relationship between the degree of crystallinity Xcf of the obtained fiber # and the dissolution temperature Wtb in water did not meet the requirements of formula (I), but met the requirements of formula (IV). (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared nonwoven fabric had a weight per unit area of 40 g / cm2, a dissolution temperature in water SP = 63t :, a degree of crystallization Xcw = 40%, and an elastic modulus M = 40 N / 50 mm. No -38-200536968 The relationship between the dissolution temperature SP in woven water and the degree of crystallinity xcw of non-woven fabric does not meet the conditions of formula (II), but meets the condition of formula (V); The relationship between the elastic modulus M of the non-woven fabric does not satisfy the condition of the formula (III), but meets the condition of the formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in (2) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 5] (1) Except that glyoxylic acid was added to the spinning dope, but was not added to the extraction bath, the spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 2. The appearance of the obtained fiber is good, and there are no defects such as gauze. The monofilament fineness was 2.3 dtex and the water-dissolving temperature Wtb was 34 ° C. However, the degree of reactivity between the fiber and glyoxylic acid is 9.9 mol% and is too high, and the degree of crystallinity Xcf of the fiber is 25% and lower, so the fiber strength is only 5.0 cN / dtex and is also low. The relationship between the degree of crystallinity Xcf of the prepared fiber and the temperature of dissolution in water Wtb does not meet the requirements of formula (I), but meets the requirements of formula (IV). (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared nonwoven fabric had a weight per unit area of 41 g / cm2, a dissolution temperature in water SP = 73 ° C, crystallization 200536968 &gt; a degree of chemical conversion X c w = 28%, and an elastic modulus M = 3 1 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric does not meet the conditions of the formula (II), but meets the condition of the formula (V); and the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric The relationship between them does not meet the conditions of formula (III), but meets the conditions of formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in item (2) above. However, the non-woven fabric was damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric was damaged. As a result, it was impossible to embroider the embroidery fabric with a beautiful appearance. [Comparative Example 6] (1) Except that the aldehyde was changed to benzaldehyde, spinning and stretching were performed under the same conditions as in Example 1 to obtain fibers. The performance evaluation results of the obtained fibers are shown in Table 2. The obtained fibers had good appearance without defects such as gauze. The monofilament fineness is 2.0 dtex. In addition, the reactivity of benzaldehyde was 1.0 mol%, and the dissolution temperature Wtb in water was 55 ° C. However, although the crystallinity Xcf of the fiber is 34%, the fiber strength is only 4.9 cN / dtex and is lower. The relationship between the degree of crystallinity Xcf of the prepared fiber and the temperature of dissolution in water Wtb did not meet the requirements of formula (I), but met the conditions of formula (IV). (2) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared non-woven fabric has a unit surface of -40-200536968 with a bulk weight of 40 g / cm2, a water solubility temperature SP = 70 ° C, a degree of crystallization Xcw = 38%, and an elastic modulus M = 35 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the degree of crystallinity Xcw of the non-woven fabric does not meet the conditions of the formula (Π), but meets the condition of the formula (V); The relationship between them does not meet the conditions of formula (III), but meets the conditions of formula (VI). (3) Although embroidery is further applied to the non-woven fabric made in (2) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 7] (1) A PVA solution having a viscosity average polymerization degree of 1,200 and a halide degree of 96.0 mol% was dissolved in water to prepare a PVA aqueous solution having a PVA concentration of 33% by mass, but it was not Glyoxylic acid was added thereto. This spinning dope was dried-spun at a rate of 500 m / min through a spinning nozzle each having a pore diameter of 0.1 mm and a number of 50 holes, and then extended 5 times at 1 3 5 ° C to produce Got fiber. The performance evaluation results of the obtained fibers are shown in Table 2. (2) The appearance of the obtained fiber is good, and there are no defects such as yarn spots. The monofilament fineness was 4.0 dUx and the dissolution temperature Wtb in water was 45 ° C. However, although the degree of crystallization Xcf is 30%, the fiber strength is only 4.8 cN / dtex and is the lower. The relationship between the degree of crystallinity Xcf of the prepared fiber and the temperature of dissolution in water Wtb did not meet the conditions of Formula (I) 200536968, but met the conditions of Formula (IV). (3) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared non-woven fabric had a weight per unit area of 39 g / cm2, a solution temperature in water SP = 55 ° C, a degree of crystallization Xcw = 35%, and an elastic modulus M = 30 N / 50 mm. The relationship between the solution temperature SP in the non-woven fabric and the degree of crystallinity xcw of the non-woven fabric does not meet the conditions of the formula (Π), but meets the condition of the formula (V); The relationship between them does not meet the conditions of formula (III), but meets the conditions of formula (VI). (4) Although embroidery is further applied to the non-woven fabric made in item (3) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 8] (1) PVA having a viscosity average polymerization degree of 400 and a haze degree of 99.9 mole% was dissolved in water to prepare a PVA aqueous solution having a PVA concentration of 39.7% by mass, and no glyoxylic acid was added. Into it, 0.3 parts by mass of sodium borate was added to prepare a spinning dope. This spinning dope was dried-spun at a rate of 500 m / min through a spinning nozzle each having a hole diameter of 0.1 mm and a number of holes of 50, and then was stretched 4 times at 130 ° C to obtain a fiber. . The performance evaluation results of the obtained fibers are shown in Table 2. 200536968, (2) The fiber produced has a good appearance and no defects such as yarn spots. The monofilament fineness was 5.0 dtex and the dissolution temperature Wtb in water was 70 ° C. However, because the degree of polymerization of the PVA used is low, although the crystallinity Xcf of the fibers is 35%, the fiber strength is only 2.7 cN / dtex and is the lower. The relationship between the degree of crystallinity Xcf of the prepared fiber and the dissolution temperature Wtb in water did not meet the requirements of formula (I), but met the requirements of formula (IV). (3) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwovens are shown in Table 4. The prepared nonwoven fabric had a weight per unit area of 41 g / cm2, a solution temperature in water SP = 72 ° C, a degree of crystallization Xcw = 40%, and an elastic modulus M = 20 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric does not meet the conditions of the formula (II), but meets the condition of the formula (V); and the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric The relationship between them does not meet the conditions of formula (III), but meets the conditions of formula (VI). ® (4) Although embroidery is further applied to the non-woven fabric made in item (3) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, the embroidery fabric having a beautiful appearance cannot be embroidered. [Comparative Example 9] (1) PVA having an average viscosity of 1,700 and a degree of hydration of 98.5 mol% was dissolved in water to prepare a PVA aqueous solution having a PVA concentration of 16.0 -43 to 200536968% by mass. No glyoxylic acid was added to it. The spinning dope thus prepared was passed through spinning nozzles each having a hole diameter of 0.16 mm and a hole number of 108 holes, and was dry-wet-spun into an aqueous solution containing a saturated crystalline sodium sulfate salt at a liquid temperature of 40 ° C in a coagulation bath. After the obtained fiber was wet-extended 3 times in water, it was then dried at 120 ° C and heat treated at 215 ° C to obtain a fiber. The performance evaluation results of the obtained fibers are shown in Table 2. (2) The appearance of the obtained fiber is good, and there are no defects such as yarn spots. The monofilament fineness was 10.0 dtex and the dissolution temperature Wtb in the water was 80 ° C. However, because the fiber is only stretched in a wet-extension mode, although the fiber's crystallinity Xcf is 40%, the fiber strength is only 4.7 cN / dtex and is the lower. The relationship between the degree of crystallinity Xcf of the prepared fiber and the dissolution temperature Wtb in water does not meet the conditions of formula (I), but meets the conditions of formula (IV). (3) The fiber obtained in the above item (1) was subjected to a heat embossing treatment under the same conditions as in Example 1 to obtain a nonwoven fabric. The evaluation results of the produced nonwoven fabric are shown in Table 4. The prepared non-woven fabric had a weight per unit area of 40 g / cm2, a solution temperature in water SP = 85 ° C, a degree of crystallization Xcw = 45%, and an elastic modulus M = 30 N / 50 mm. The relationship between the dissolution temperature SP in the non-woven fabric and the crystallinity Xcw of the non-woven fabric does not meet the conditions of the formula (Π), but meets the condition of the formula (V); and the dissolution temperature SP in the non-woven fabric and the elastic modulus M of the non-woven fabric The relationship between them does not meet the conditions of formula (III), but meets the conditions of formula (VI). -44- 200536968 (4) Although embroidery is further applied to the non-woven fabric made in item (3) above. However, the non-woven fabric is damaged due to the embroidery needles, and the surface of the fibers used to constitute the non-woven fabric is damaged. As a result, it is impossible to embroider a beautiful embroidery fabric.

-45- 200536968 -46- 1 Fiber physical properties XL ^ Yunxin 1 Spinning 'Extension condition PVA polymer composition Wtb and Xcf Relationship Wtb (° C) Fiber strength (cN / dtex) Crystallinity Xc (% ) Reactivity (mol%) of ionic group-containing compounds Monofilament fineness (dtex) Degree of neutralization of ionic groups (mol%) The amount of the above-mentioned impurities (g / 1) The addition step of the above-mentioned compounds contains ionicity Total extension ratio (times) of basicized hybrid surface Elongation temperature (.C) Degree of polymerization of solvent spinning method Solution degree (mol%) Meets the requirements of formula (I) μ 1/1 U) 00 〇v〇b 〇Η- »〇 Extraction bath surface 〇 \ ON ο DMSO dry-wet I spinning 1 1,700 VO Os Example 1 meets the requirements of formula (I) Η- ^ ο bo Μ 1—k 〇 extraction bath glyoxylic acid Sodium neutralization 〇 \ as ο DMSO dry-wet spinning 1,700 Ό Os Example 2 Conditions in accordance with formula (I) U) ON U) K) ο Ha 〇One extraction bath glyoxylic acid as α \ ο DMSO dry -Wet spinning 1,700 000 〇〇 Example 3 meets the requirements of formula (I) On K) Os b \ ο bo K) k) 〇 Extraction bath glyoxylic acid Os ο DMSO 1 dry-wet spinning I 1,700 SO 00 Example 4 Meets the requirements of formula (I) 〇 Lh 00 Ln s VO K> b Extraction bath 丨 Sodium glyoxylate 丨 Neutralizer—K) ο DMSO Dry-wet spinning 1,700 VO 00 Example 5 Meet the requirements of formula (I) 1— ^ 00 o — b M k) ο Sodium glyoxylate neutralization in the extraction bath ο Wet spinning 1,700 I Ό ON 1 Example 6 | 200536968

Comparative Example 9 in od ON ο wet spinning 0cn 1 1 1 1 〇〇1-H 1 〇 g g meets the requirements of formula (IV) Comparative Example 8 ON Ch σ \ ο ο dry knot τ- ^ inch 1 1 1 1 〇1 Bu rvi o 1 Complies with the condition αν) 丨 Comparative example 7 v〇Os ο (N il cn τ-Η 1 1 1 1 p 1 00 »r &gt; Compatible with condition (IV) Comparative Example 6 VD 〇 \ ο rH Dry-wet fleece | DMS0 | Ο VO 1 Benzaldehyde 1 Extraction bath 〇τ-Η 〇〇 (Ν P ^ T) Conditions in accordance with formula (IV) Comparative Example 5 ON ο ο Dry- Wet knotting | DMSO | ο SO v〇 "glyoxylic acid | stock solution 〇〇m ON 0's (N 〇 conditions in accordance with formula (IV) Comparative Example 4 v〇On ο dry-wet spinning | DMSO | ο νο \ o I glyoxylic acid | 1 is given 1 〇〇 ^ Τ) (N rH CN m * T) Complies with the condition of formula (IV) Comparative Example 3 〇〇ON ο Τ · Η Dry-wet knotting | DMSO | ο Ό 1 1 1 1 Ο) 1 Os tri VO Conforms to the requirements of formula (IV) Comparative example! __2__ OO 00 〇 Dry-wet spinning 1 DMSO ο ν〇Ό 1 1 1 1 Ο 1 VO * T) (IV) Conditions Comparative Example 1 VO ON ο Τ-Η Dry-wet knot 丨 DMSO ο ν〇v〇 window 1 1 1 ο Η 1 cn iT) Complies with the conditions of formula (IV) Degree of polymerization (mol%) Degree of polymerization Spinning method Stock solution solvent elongation temperature (.C) Total elongation ratio (times) Including Steps for adding the above compounds to the ionic group. The addition amount of the above compounds (g / ι). The degree of neutralization of the ionic group (mol%). The monofilament fineness (dtex). The degree of reactivity of the compound containing ionic groups (mol). %) Crystallinity Xc (%) Fiber strength (cN / dtex) Wtb (° c) Relationship between Wtb and Xcf PVA-based polymer component spinning 'extension conditions shoot 8_ Fiber characteristics 200536968 Example 4 〇m oo Ό H: Example 3 1-H CS m H pH Example 2 m CO VO JO H: Example 1 〇 «ο H = (ε ιΜ Fine) S5 Η 酹 Degree of crystallization Xcw (%) Dissolution temperature in water SP ( ° c) Modulus of elasticity M (N / 50mm) Formula conforming to the relationship between SP and Xcw Formula conforming to the relationship between SP and M Non-woven properties Comparative Example 8 1 rH Ο &gt; Comparative Example 7 On cn cn &gt; Comparative Example 6 ο 00 O Γ〇 &gt; &gt; Comparative Example 5 τ-Η inch 00 ra rn m &gt; Comparative Example 4 Ο om Ό Ο &gt; Comparison Example 3 ο sm as s &gt; Comparative Example 2 ο fs On t—H &gt; Comparative Example 1 ο m &gt; _ \\ m \\ ρ S5 la nmL Weng crystallinity Xcw (%) Dissolution temperature in water SP rc) Elastic modulus M (N / 50mm) Formula that meets the relationship between SP and Xcw Formula that meets the relationship between SP and M Non-woven fabric properties

200536968 From the results of Table 1 and Figure 1, it is clear that the water-soluble PVA fiber of the present invention has both excellent water solubility and excellent fiber strength. In addition, depending on the degree of neutralization of the ionic groups, the water solubility of the fibers can be easily controlled. On the other hand, it is clear from the results in Table 2 that the fibers prepared according to the conventional technology are processed with an ionic group-containing compound that does not meet the requirements of the composition requirements of the present invention, and that they do not meet the requirements of the present invention. From the viewpoint of the reactivity of the compound, the conditioner of the compound containing the ionic group is inferior to the fiber of the present invention compared with the fiber of the present invention, and the reason is that it is compared with the fiber of the present invention, even if they are Although it has a low degree of crystallization, its dissolution temperature in water is high, and its mechanical properties such as fiber strength are also poor. It is obvious from Tables 3 and 2 and 3 that the water-soluble non-woven fabric of the present invention has both excellent water solubility and excellent mechanical properties. Therefore, when embroidering the non-woven fabric of the present invention, a non-woven fabric having a beautiful appearance can be obtained. On the other hand, it is clear from the results in Table 4 that the non-woven fabric made according to the conventional technology and the non-woven fabric made of fibers that do not meet the requirements of the composition requirements of the present invention are inferior to the non-woven fabric of the present invention. The reason is that compared with the nonwoven fabric fibers of the present invention, even though they have a low degree of crystallinity, their dissolution temperature in water is high and their mechanical properties are poor. Therefore, when embroidery is applied to the nonwoven fabric, they cannot provide a embroidery fabric having an excellent appearance. [Industrial Applicability] According to the present invention, a water-soluble 200536968 PVA fiber having excellent water-solubility characteristics and excellent mechanical properties, such as excellent tensile strength, which cannot be achieved by conventional techniques, is provided. The water-soluble PVA-based fiber system of the present invention can be produced inexpensively without any special steps by ordinary spinning and drawing steps. In addition, the water-solubility characteristics of the water-soluble PVA-based fiber of the present invention can be appropriately controlled. In addition, the water-soluble PVA-based fiber of the present invention can produce a water-soluble nonwoven fabric having both excellent water solubility characteristics and excellent mechanical properties such as excellent elastic modulus, which cannot be achieved by conventional techniques. The non-woven fabric of the present invention is expected to have many uses, for example, it can be effectively used as a base fabric for chemical burning of lace. [Brief Description of the Drawings] Figure 1 shows the water-soluble PVA fibers of the present invention. The water-soluble PVA fibers disclosed in Japanese Patent Laid-Open Nos. 7-4201 9 and 7-90714 are disclosed in Japanese Patent Publication No. 7-4201. And "Solvron" series made by Nitivy, in which the relationship between the water solubility temperature (Wtb) of each fiber and the crystallinity (Xcf) of the fiber. FIG. 2 shows a non-woven fabric composed of the water-soluble PVA-based fibers of the present invention, and is composed of the water-soluble PVA-based fibers disclosed in Japanese Patent Laid-Open Nos. 7-42019 and 7-907 14 The relationship between the dissolving temperature SP (° C) in water of each nonwoven fabric and the crystallinity Xcw (%) of the nonwoven fabric and the sheet made of "Solvron" series made by Nitivy. FIG. 3 shows a non-woven fabric made of the water-soluble, PVA-based fibers of the present invention, and water-soluble PVA-based fibers disclosed in Japanese Patent Laid-Open No. 7-4201 9 and Japanese Patent Laid-Open No. 7-907 14. The non-woven fabric and the sheet made of the "Solvron" series made by Nitivy, among which 200536968 is the temperature between the solution temperature SP (° c) of each non-woven fabric and the elastic modulus M (N / 50 mm) of the non-woven fabric. relation chart. [Description of main component symbols] j \ \\

-51-

Claims (1)

200536968 10. Scope of patent application: 1. A water-soluble polyvinyl alcohol-based fiber, which is characterized by reacting with 0.01 to 5 mol% of an ionic group-containing compound, and the degree of crystallinity Xcf (%) of the fiber is in water. The relationship between the dissolution temperature Wtb (it) meets the conditions of the following formula (I): Wtb &lt; 2.50 · Xcf-70 (I) where 30% S Xcf $ 80%. 2. The water-soluble polyvinyl alcohol-based fiber according to item 1 of the patent application scope, wherein the ionic group-containing compound is glyoxylic acid or a glyoxylic acid neutralized substance. 3. A method for manufacturing water-soluble polyvinyl alcohol-based fibers, for manufacturing water-soluble polyvinyl alcohol-based fibers such as those in item 1 or 2 of the scope of patent application, which will have a degree of polymerization of 1,000 to 4,000 and a degree of tritification A spinning dope prepared by dissolving a polyvinyl alcohol polymer of 88 mol% or more in an organic solvent, wet or dry-wet spinning into the organic solvent containing the polymer as a main component Coagulation bath, followed by passing it through an extraction bath containing 1 to 50 g / 1 of the ionic group-containing compound dissolved therein, soaking the compound into the fiber, and reacting it in any of the steps of drying, stretching, and heat treatment It is introduced, and the fibers are stretched to a total stretch ratio of 3 times or more in all the steps. 4. A water-soluble non-woven fabric, characterized by being composed of water-soluble polyvinyl alcohol-based fibers as described in any one of claims 1 to 3, and having a degree of crystallization Xcw (%) of the non-woven fabric and a solution temperature in water The relationship between SP (° C) complies with the following formula (Π): SP &lt; 2.50 · Xcw-50 (II) -52- 200536968 In the formula, 30% ^ Xcw ^ 65%. 5. As for the water-soluble non-woven fabric in the scope of the patent application, the relationship between the non-woven elastic modulus M (N / 5 0 mm) and the solution temperature SP (° C) in water meets the requirements of the following formula (IΠ) : SP &lt; 1.60 Μ-22 (III) where 30 N / 50 mm SMS 80 N / 50 mm. -53-