JP2001115333A - Meta-aromatic polyamide solution and method for producing fiber by using the same solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a meta-aromatic polyamide solution capable of providing a fiber excellent in qualities in good process conditions by wet spinning and suitable for wet spinning in which productivity is remarkably improved. SOLUTION: This organic polar solvent solution has 12-18 wt.% concentration of meta-aromatic polyamide such as poly(meta-phenylene isophthalamide), 3-25 wt.% calcium chloride content based on polyamide weight and 25-70 wt.% water content and is suitable for wet spinning and includes N-methyl-2- pyrrolidone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meta-type aromatic polyamide solution suitable for wet spinning and a method for producing a meta-type aromatic polyamide fiber which uses the solution and has remarkably improved quality and productivity. .

[0002]

2. Description of the Related Art As a method for producing a meta-type aromatic polyamide fiber, a spinning solution obtained by dissolving a meta-type aromatic polyamide in a solvent is extruded into a coagulation liquid of an aqueous solution of an inorganic salt, and a coagulated yarn is drawn. Methods for washing, stretching and heat treatment are known. The spinning dope may contain an inorganic salt (eg, calcium chloride) as a dissolution aid for the polyamide, but the content of the inorganic salt is generally about 45% by weight based on the weight of the polyamide.

As an example of wet spinning of a spinning stock solution containing substantially no inorganic salt, metaphenylenediamine and isophthalic chloride are reacted in an organic solvent that is not a good solvent for the polyamide to be formed (eg, in tetrahydrofuran). The resulting solution or dispersion is brought into contact with an aqueous solution of an inorganic acid acceptor to complete the reaction, thereby isolating a polymetaphenylene isophthalamide polymer powder (see JP-B-47-10863). A method has been proposed in which the coalesced powder is redissolved in an amide solvent and then wet-spun in an aqueous coagulation bath containing an inorganic salt (see JP-B-48-17551). However, in such a method, special consideration and meticulous process control are required to obtain a solution having excellent storage stability by re-dissolving, and it has been pointed out that the productivity is still insufficient. (See Japanese Patent Publication No. 48-4661).

An example of wet spinning of a spinning solution having a low content of inorganic salts is as follows:
Initially polymerize the raw material until the reaction rate reaches, neutralize the generated hydrogen halide with ammonia, separate the insoluble ammonium halide, then post-polymerize by adding the remaining amount of the raw material, A solution obtained by neutralizing the hydrogen halide generated in the solution with calcium hydroxide or the like, and wet spinning the solution as it is (Japanese Patent Application Laid-Open No.
128096). But,
In such a method, it is difficult to completely remove the insoluble ammonium halide salt from the neutralized reaction intermediate product, so that not only the spinning nozzle is easily contaminated, but also the stability during wet spinning is still insufficient. There is a problem that there is.

On the other hand, when a spinning dope containing an inorganic salt in a high concentration, such as an inorganic salt content of about 45% by weight or more based on the meta-type aromatic polyamide, is wet-spun, the fiber is coagulated during the coagulation process. Various methods for improvement have been conventionally proposed because voids are easily generated.

For example, JP-A-10-88421 and JP-A-10-53920 disclose that the salt content is 3%.
A meta-type aromatic polyamide solution containing a high concentration of at least 1% by weight (solution concentration) is used as a spinning solution, and coagulated at a specific range of temperature using an aqueous coagulation bath having a solvent and salt concentration within a specific range. A method has been proposed in which after a treatment with a condition adjusting solution having a concentration and a salt concentration in a specific range at a temperature within a specific range, stretching is performed at a temperature within a specific range in an aqueous stretching bath having a solvent concentration and a salt concentration within a specific range. . Certainly, according to such a method, although a fiber excellent in mechanical properties with less generation of voids can be obtained, the productivity is inferior to a method using a spinning solution that does not substantially contain the inorganic salt. There is a problem that there is.

Another method is disclosed in Japanese Patent Application Laid-Open No. 8-7412.
No. 1 and JP-A-8-74122 disclose a meta-type aromatic polyamide solution containing by-product hydrochloric acid obtained by reacting an aromatic diamine and an aromatic dicarboxylic acid dichloride in an amide solvent. Add a specific amount of amide-based solvent and water to a solution containing a high concentration of inorganic salt, which is neutralized with an inorganic alkali such as calcium oxide, calcium oxide, and calcium carbonate, to adjust the polymer concentration and water concentration to a specific range. There has been proposed a method of performing wet spinning using the resulting solution as a spinning solution. According to this method, even when an aqueous coagulation bath is used, the penetration of the coagulant into the yarn is suppressed, and a fiber having little voids and excellent transparency is obtained stably, and the stretchability of the fiber is good. Therefore, a drawn fiber having excellent mechanical properties can be obtained. However, in such a method, when the number of discharge holes of the spinneret is as large as 1000 to 30,000, it is difficult to perform wet spinning stably, and there is a problem that fibers having excellent quality cannot be manufactured with high productivity. .

[0008]

SUMMARY OF THE INVENTION The present invention has been made on the background of the state of the prior art as described above. It is an object of the present invention to be able to wet-spin fibers of excellent quality in a good process and to improve productivity. It is an object of the present invention to provide a meta-type aromatic polyamide solution for wet spinning, which is dramatically improved, and a method for producing a fiber using the same.

[0009]

According to the study of the present inventors, the above object was achieved when the concentration of the meta-type aromatic polyamide was 12%.
An organic polar solvent solution of about 18% by weight, wherein the solution contains 3 to 25% by weight of calcium chloride and 25 to 70% by weight of water, based on the weight of the polyamide. It has been found that this can be achieved by a meta-type aromatic polyamide solution described below.

It has been found that another object can be achieved by a method for producing a fiber in which the above-mentioned meta-type aromatic polyamide solution is wet-spun, then washed with water and then drawn.

[0011]

Embodiments of the present invention will be described below in detail. The meta-type aromatic polyamide targeted by the present invention is a polymer obtained from the reaction of a meta-type aromatic diamine and a meta-type aromatic dicarboxylic acid halide exemplified below, within a range that does not inhibit the object of the present invention. And may have another copolymerization component such as para-type.

Examples of the meta-type aromatic diamine include metaphenylenediamine, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylsulfone, and the like, and halogens and alkyl groups having 1 to 3 carbon atoms on these aromatic rings. Derivatives having a substituent of, for example, 2,4-toluylenediamine, 2,6-toluylenediamine, 2,4-diaminochlorobenzene, 2,6-diaminochlorobenzene and the like can be used. Among them, metaphenylenediamine or the above-mentioned mixed diamine containing at least 80 mol%, preferably at least 90 mol%, particularly preferably at least 95 mol% of metaphenylenediamine is preferred.

Examples of the meta-type aromatic dicarboxylic acid halide include isophthalic acid halides such as isophthalic acid chloride and isophthalic acid bromide, and derivatives having a substituent on the aromatic ring such as a halogen atom or an alkoxy group having 1 to 3 carbon atoms; For example, 3-chloroisophthalic acid chloride, 3
-Methoxyisophthalic chloride can be used. Among them, isophthalic acid chloride or the above-mentioned mixed carboxylic acid halide containing isophthalic acid chloride in an amount of 80 mol% or more, preferably 90 mol% or more, particularly preferably 95 mol% or more is preferable.

The copolymerizable components other than the above-mentioned diamines and carboxylic acid halides include aromatic diamines such as benzene such as paraphenylenediamine, 2,5-diaminochlorobenzene, 2,5-diaminobromobenzene and aminoanisidine. Derivatives, 1,5-naphthylenediamine, 4,4′-diaminodiphenyl ether, 4,4 ′
-Diaminodiphenylketone, 4,4'-diaminediphenylamine, 4,4'-diaminodiphenylmethane and the like, while the aromatic dicarboxylic acid halides include terephthalic acid chloride, 1,4-naphthalenedicarboxylic acid chloride, 6-naphthalenedicarboxylic acid chloride, 4,4'-biphenyldicarboxylic acid chloride, 4,4'-diphenylethercarboxylic acid chloride and the like can be mentioned. If the copolymerization amount of these copolymerization components is too large, the properties of the meta-type aromatic polyamide tend to deteriorate, so that preferably 20 mol% or less, especially 10 mol% or less based on the total acid components of the polyamide. Appropriate.

Particularly preferably, the meta-type aromatic polyamide is used in an amount of at least 80 mol%, preferably at least 90 mol%, particularly preferably at least 95 mol%, more preferably at least 100 mol%, of the total repeating units. It is a polyamide consisting of units.

The degree of polymerization of the meta-type aromatic polyamide is determined by measuring the intrinsic viscosity (I) measured using concentrated sulfuric acid at 30 ° C. as a solvent.
The range where V) is 1.3 to 3.0, preferably 1.7 to 2.2 is appropriate.

As the solvent for the meta-type aromatic polyamide used in the present invention, N-methyl-2-pyrrolidone (NM
P), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DM
Polar organic solvents such as SO), and among them, NMP or DMAc is preferable.

In the present invention, if the above-mentioned polymer and organic polar solvent are used, the meta-type aromatic polyamide solution has a concentration of 12 to 18% by weight, preferably 15 to 17% by weight.
And 3 to 25% by weight, preferably 10 to 20% by weight, and 25 to 70% by weight, preferably 30 to 50% by weight of calcium chloride, based on the weight of the polyamide.
% By weight.

When the polymer concentration is less than 12% by weight, it is presumed that the viscosity of the solution becomes too low, and wet spinning becomes difficult. On the other hand, if the content exceeds 18% by weight, the stability of the solution is reduced due to the high concentration of water in the solution, and the solution is apt to gel, and it is difficult to perform stable wet spinning.

When the content of calcium chloride is less than 3% by weight based on the weight of the polyamide, the stability of the solution in which water coexists is reduced and the solution is easily gelled, so that it is difficult to perform stable wet spinning. Becomes On the other hand, when the content exceeds 25% by weight, even if a solution containing water in the above range is used, if the spinning speed is increased during wet spinning, large voids are likely to be generated in the yarn in the coagulation step, and the process condition This is not preferred because not only does the productivity worsen and the productivity decreases, but also the quality of the resulting fiber decreases.

If the water content is less than 25% by weight based on the weight of the polyamide, the coagulability during wet spinning is reduced, and voids are easily generated in the yarn. On the other hand, 70
If the content is more than 10% by weight, the stability of the solution is lowered and gelation is likely to occur, and it is difficult to perform stable wet spinning.
Conventionally, the presence of water in the spinning solution during wet spinning not only impairs the stability of the spinning solution,
It was thought that there was no merit because the spinnability was also reduced. In recent years, Japanese Patent Application Laid-Open No. H08-74122 discloses that if the inorganic salt is contained in a large amount of 47% by weight relative to the polymer, a spinning solution containing a large amount of water may be used. Although it is disclosed that not only the quality of the obtained fiber is suppressed but also the productivity is improved, the generation of voids during wet spinning is still suppressed when the content of the inorganic salt is still small. Because it is unlikely to occur, the addition of water to the spinning solution was considered meaningless. However, according to the study of the present inventors, even in the case of a spinning solution having a low inorganic salt content as in the present invention, it is estimated that coexistence of water improves coagulability during wet spinning. It has been found that fibers of good quality can be obtained even if the speed is dramatically increased. That is, when wet spinning is performed using a spinning solution having a water content of 25% by weight or less with respect to the polymer, not only is it easy to cause agglomeration between fibers in the high spinning speed region where the spinning speed is 15 m / min or more. Transparency also decreases, and if the coagulation time is lengthened by lengthening the coagulation bath to cover this problem, problems such as transparency can be solved, but the problem that fluff at the time of stretching increases will occur. On the other hand, it has been found that when the water content is 25% by weight or more, the coagulability is improved, the spinning speed can be improved, and the quality of the obtained fiber is also improved.

The method for preparing the meta-type aromatic polyamide solution of the present invention is not particularly limited. For example, a polymer produced by interfacial polymerization or solution polymerization is once isolated and then dissolved in an organic polar solvent. Any method can be adopted, such as a method of obtaining a solution having a predetermined concentration, calcium chloride and water content, and a method of directly adjusting a reaction solution obtained by solution polymerization to a predetermined concentration, calcium chloride and water content. In addition, when preparing directly from the reaction solution of solution polymerization, it may be prepared after neutralizing the acid generated by the polymerization. Further, as long as the object of the present invention is not impaired, other aromatic polyamides and the like may be used in combination, or conventionally known additives such as pigments, matting agents and stabilizers may be used.

The above-described meta-type aromatic polyamide solution of the present invention can be produced using a conventionally known wet spinning apparatus. That is, the solution is directly extruded into a coagulating liquid to coagulate into a fiber. The coagulated fiber is drawn out of the coagulation bath, and after adjusting the concentration of the residual solvent in the fiber through a water washing step (preferably a multi-stage water washing step), stretched in warm water, dried, and heat-set as necessary. It is supplied to the post-process by collecting it as a can, winding it up, or directly sending it to the post-process, applying crimping, and cutting it into short fibers when necessary.

The number of spinning holes of the spinneret used here is as follows:
Although it may be used for 50 to 1000 filaments, the effect of the present invention can be maximized by 1000 to 3000 filaments.
This is a case where a spinneret for zero swoof is used. That is, since the coagulability of the solution is improved, it is possible to stably coagulate in a coagulation bath even if the number of spinning holes is large, and to stably spin at a high speed. The spinning hole diameter is 0.
05-0.2 mm is generally used. The temperature of the meta-type aromatic polyamide solution during spinning is suitably in the range of 50 to 90 ° C.

As the coagulating liquid, a conventionally known aqueous solution of an inorganic salt can be used. For example, an aqueous solution having a calcium chloride concentration of 34 to 42% by weight and an NMP concentration of 5 to 10% by weight is exemplified as a preferable one. The temperature of the coagulation liquid is suitably in the range of 80 to 95 ° C.

The speed at which the coagulated fiber is withdrawn from the coagulation bath can be in the range of 5 to 25 m / min. However, from the viewpoint of the purpose of the present invention for improving the productivity, the speed is preferably in the range of 10 to 25 m / min. preferable. The immersion time of the fiber in the coagulation liquid is
A range of 1.0 to 11 seconds is appropriate.

The fiber extracted from the coagulation liquid is sent to a hot water drawing step through a water washing step, and the water washing step is preferably performed in multiple stages. That is, the fiber drawn from the coagulation liquid is cooled to 60 ° C. or lower and then introduced into a first washing bath at 30 ° C. or lower. The concentration of the organic polar solvent (for example, NMP) in the first washing bath is preferably in the range of 15 to 25% by weight, and the flow rate of the replenishing washing water and the solvent concentration in the washing water are determined so that the concentration can be maintained. The immersion time of the fibers in the first washing bath is preferably 8 to 30 seconds. Then 30
It is introduced into a second washing bath at ８５85 ° C. for washing. The amount of washing water replenished in the washing bath, the concentration of the solvent in the washing water, and the immersion time of the fibers in the washing bath are as follows: the amount of the residual solvent in the fibers leaving the washing step is 12 to 25% by weight relative to the polymer; Is appropriately selected and set such that the calcium concentration of the becomes 0.5% by weight or less.

The remaining solvent and calcium salt are washed and removed while the fiber whose residual solvent amount and calcium amount have been adjusted in the water washing step is stretched 2.8 to 3.5 times in the hot water drawing step. Stretching is preferably performed in two or more stages, and more preferably in three or more stages, in order to maintain good process conditions.

The drawn fiber is dried at a temperature of 100 ° C. or more, and then heated at a temperature of 270 to 350 ° C. with a heating roller or a hot plate.
Heat set at the temperature.

The meta-type aromatic polyamide fiber thus obtained can be collected as a tow, wound up, or sent directly to a post-process, if necessary, and then cut after crimping, if necessary. And provided to the subsequent process.

[0031]

EXAMPLES The present invention will be described below more specifically with reference to examples. Each characteristic value in the examples was measured by the following method. <Intrinsic viscosity (IV)> The polymer was dissolved in 97% concentrated sulfuric acid, and measured at 30 ° C. using an Ostwald viscometer. <Fineness> Measured according to JIS-L-1015. <Strength and elongation> Test length 2 in accordance with JIS-L-1074
0mm, initial load 0.05g / de, elongation speed 20mm /
Measured in minutes.

Example 1 100 parts by weight of a polymetaphenylene isophthalamide powder having an IV of 1.95 was added to water 40
A solution prepared by dissolving and dispersing 15 parts by weight of anhydrous calcium chloride in parts by weight was mixed with 466 parts by weight of NMP and dispersed in a solution cooled to -5 ° C. (Polymer concentration: 16.1% by weight)
And

This spinning solution was used with a pore size of 0.07 mm and a pore number of 1
It was extruded directly into the coagulating liquid from a spinneret of 5000 and made into a fiber form and pulled out. The composition of the coagulating liquid is calcium chloride 40
It was an aqueous solution containing 5% by weight of NMP and 5% by weight of NMP, and the temperature of the coagulating liquid was 90 ° C. The immersion time of the fiber in the coagulating liquid was set at 1.
It was set to 7 seconds and pulled out at a speed of 16 m / min.

After cooling the fiber to 50 ° C.,
It was introduced into a first washing bath at 5 ° C., and then washed through a second washing bath at 45 ° C. and a third washing bath at 70 ° C. until the residual solvent in the fiber became 18% by weight relative to the polymer. At this time, the aqueous solution composition of the first washing bath was 22% by weight of NMP and 14% by weight of calcium chloride.

The fibers after washing are successively drawn in hot water at 98 ° C. in a first stage draw ratio of 1.4 times and a second stage draw ratio of 1.95.
And three-stage stretching at a third-stage stretching ratio of 1.1 times. When the fiber bundle after the completion of the hot water drawing was observed during running, the fluff was a good and glossy fiber of less than 1 fiber / minute.

The stretched fiber is dried through a drying roller at 70 ° C., preheated by a preheating roller at 200 ° C., heat-set by a roller at 340 ° C., cooled to 30 ° C. by a cooling roller, and then coated with an oil agent. Rewind 30,000de / 1
A 5000 filament drawn tow was obtained.

[Example 2] In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Parts by weight, 43 parts by weight of water, 10 parts by weight of calcium chloride and 472 parts by weight of NMP (polymer concentration:
16% by weight). This spinning solution was subjected to coagulation, washing with water, hot water stretching and heat setting in the same manner as in Example 1,
A stretched tow of 00de / 15000 filaments was obtained.
In addition, when the fiber bundle after hot water drawing was observed during running,
The fluff was a good and glossy fiber of less than 1 / min.

Example 3 968 parts by weight of NMP having a water content of 100 ppm or less were placed in a reaction vessel equipped with a thermometer, a stirrer, and a raw material inlet, and 100 parts by weight of metaphenylenediamine was dissolved in the NMP. Cooled to 0 ° C.
To the cooled diamine solution, 188 parts by weight of isophthalic acid chloride (hereinafter abbreviated as IPC) was added with stirring and reacted. In this reaction, the temperature of the solution rose to 70 ° C. After stirring for 60 minutes from the start of the reaction, an NMP slurry of calcium hydroxide (concentration: 22.5% by weight)
Was added, and the mixture was stirred for 20 minutes. Then, 109 parts by weight of an aqueous sodium hydroxide solution (concentration: 48.6% by weight) was added. The mixture was stirred for 60 minutes to terminate the reaction, and the polymerization solution was taken out. The sodium was filtered to obtain a clear polymerization solution.

From this polymerization solution, polymetaphenylene isophthalamide was isolated and its IV was measured to be 1.97
Met. The solution had a polymer concentration of 16% by weight, a calcium chloride concentration of 15% by weight relative to the polymer, and a water concentration of 39% by weight relative to the polymer.

Water / NMP = 100 parts by weight of this polymerization solution
3.2 parts by weight of a 25/100 solution was added and mixed to obtain a transparent spinning solution. The polymer concentration of this spinning solution is 1
At 5.5% by weight water was 44% by weight relative to the polymer.

This spinning solution was subjected to coagulation, washing with water, hot water stretching and heat setting in the same manner as in Example 1 to obtain 30,000 d
An e / 15,000 filament drawn tow was obtained. Also,
When the fiber bundle after hot water drawing was observed during running, the fluff was a good and glossy fiber of less than 1 fiber / minute.

Comparative Example 1 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Part by weight, 15 parts by weight of water, 47 parts by weight of calcium chloride and 607 parts by weight of NMP (polymer concentration:
13% by weight). The spinning solution was subjected to coagulation, washing, hot water drawing and heat setting in the same manner as in Example 1. However, a single yarn break was observed in the fiber bundle drawn out of the coagulation solution, and the fluff after hot water drawing was 100%. And the gloss of the fiber was not good. In addition, the winding of the fiber around the drying roller, the preheating roller, and the heat setting roller occurred frequently, and sufficient winding could not be performed.

Comparative Example 2 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Parts by weight, 50 parts by weight of water, 47 parts by weight of calcium chloride and 572 parts by weight of NMP (polymer concentration:
13% by weight). The spinning solution was subjected to coagulation, washing, hot water drawing and heat setting in the same manner as in Example 1. Although no single yarn was broken in the fiber bundle drawn out of the coagulation solution, the spinning solution after hot water drawing was used. The fluff was as high as 100 / min or more, and the fiber gloss was not good. In addition, wrapping around the drying roller, preheating roller, heat setting roller frequently occurs,
Sufficient winding could not be performed.

Comparative Example 3 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
A spinning solution (polymer concentration: 21% by weight) consisting of parts by weight and 376 parts by weight of NMP was obtained. This spinning solution was subjected to coagulation, washing, hot water drawing, and heat setting in the same manner as in Example 1. However, the fiber bundle drawn out of the coagulation solution was found to have single yarn breaks, and there was also sticking between fibers. , Could not be passed through the hot water stretching step.

Comparative Example 4 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Parts by weight, 20 parts by weight of water, 15 parts by weight of calcium chloride and 490 parts by weight of NMP (polymer concentration:
16% by weight). This spinning solution was subjected to coagulation, washing with water, hot water stretching and heat setting in the same manner as in Example 1, but
The fluff after hot water stretching was as high as 100 / min or more, and the luster of the fiber was low. In addition, winding of the fiber around the drying roller, the preheating roller, and the heat setting roller occurred.

Comparative Example 5 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Parts by weight, 80 parts by weight of water, 15 parts by weight of calcium chloride and 430 parts by weight of NMP (polymer concentration:
(16% by weight), but a spinning was not possible due to the formation of a gel during spinning.

Comparative Example 6 In the same manner as in Example 1, the IV
1.95 polymetaphenylene isophthalamide 100
Parts by weight, 20 parts by weight of water, 1 part by weight of calcium chloride and N
A spinning solution consisting of 504 parts by weight of MP (polymer concentration: 1
(6% by weight), but a gel was generated during spinning and spinning was not possible. The above results are summarized in Table 1.

[0048]

[Table 1]

[0049]

The meta-type aromatic polyamide solution of the present invention described above is excellent in stability and coagulability during wet spinning, so that a meta-type aromatic polyamide fiber of good quality can be obtained. It is possible to produce with good productivity under excellent process conditions.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirozumi Iwasaki 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. (72) Inventor Kotaro Takigami 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Teijin Shares F-term in the Iwakuni Works (reference) 4J001 DA01 DB01 DB04 DC16 DD04 DD06 EB36 EC44 EC45 EC56 EC66 EC67 EC68 EC69 EC70 EE06F EE08F EE53F EE64F FA01 FB03 FB05 FC03 FC05 FD01 HA02 HA10 JA10 JC04 4J002 FD061 DD0208FD0627 AA06 AA08 BB03 BB10 BB13 BB16 BB66 BB72 BB89 BB91 BB93 DD19 MG04 4L045 AA02 BA03 BA60 CB09 CB13 DA03 DA14 DA32 DA34 DA42 DC02

Claims (5)

[Claims] 1. The method according to claim 1, wherein the concentration of the meta-type aromatic polyamide is 12 to
18% by weight of an organic polar solvent solution, characterized in that the solution contains 3 to 25% by weight of calcium chloride and 25 to 70% by weight of water based on the weight of the polyamide. Meta-type aromatic polyamide solution. 2. The meta-aromatic polyamide solution according to claim 1, wherein the meta-aromatic polyamide comprises at least 85 mol% of the total repeating units composed of meta-phenylene isophthalamide units. 3. The meta-type aromatic polyamide solution according to claim 1, wherein the organic polar solvent is N-methyl-2-pyrrolidone or dimethylacetamide. 4. A method for producing a meta-type aromatic polyamide fiber, comprising: spinning the solution of the meta-type aromatic polyamide according to claim 1 in a coagulation bath, washing with water, and drawing. 5. The method for producing a meta-type aromatic polyamide fiber according to claim 4, wherein the coagulating liquid is an aqueous solution of an inorganic salt.