KR20130075196A - Aramid fiber and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An aramid fiber, and a manufacturing method thereof are provided to manufacture without using a sulfuric acid solvent by using a polymerization solution as a spinning dope, and to have a high crystallinity and intensity. CONSTITUTION: An aramid fiber comprises: a recurring unit of chemical formula 1, and a recurring unit of chemical formula 2. The aramid fiber has more than 65% of crystallinity, and more than 22g/denier of intensity. A manufacturing method thereof comprises: dissolving substituted aromatic diamine whose benzene ring hydrogen is substituted for -CN, -Cl, -SO_3H, or -CF_3, and non-substituted aromatic diamine in an organic solvent; adding aromatic diacid halide to the solvent above to obtain a polymerization solution; extruding the polymerization solution through spinneret; and forming filament by passing the extruded polymerization solution through a coagulant.

Description

Technical Field The present invention relates to an aramid fiber,

The present invention relates to aramid fibers and a method for manufacturing the same, and more particularly, by using a polymerization solution as a spinning dopant not only can be prepared without the use of a sulfuric acid solvent, but also has a high crystallinity and high strength and a method for producing the same It is about.

Aromatic polyamides, commonly referred to as aramids, include para-aramids having a structure in which benzene rings are linearly connected through an amide group (CONH), and meta-based aramids that are not.

Para-aramid has excellent properties such as high strength, high elasticity and low shrinkage. The thin thread with a thickness of 5 mm manufactured from it has a strength enough to lift a 2 - tonne automobile and is used not only for bulletproof but also for various applications in high - tech industry in aerospace sector.

In addition, since aramid is carbonized black at a temperature of 500 ° C or higher, it is also in the spotlight where high heat resistance is required.

The method for producing aramid fibers is well described in the applicant's Korean Patent No. 10-0910537. According to this registered patent, an aromatic diamine is dissolved in a polymerization solvent to prepare a mixed solution, and aromatic dieside is added thereto to prepare an aramid polymer. The aramid fiber is finally completed by dissolving the aramid polymer in a sulfuric acid solvent to prepare a spinning dope, spinning the spinning dope, followed by coagulation, washing, and drying.

However, when the aramid fiber is manufactured through such a process, since the solid aramid polymer is manufactured and then dissolved in a sulfuric acid solvent to spin the dope to prepare a spinning dope, the manufacturing process is complicated and harmful to the human body. There are problems such as deterioration of durability due to corrosion.

Furthermore, since the sulfuric acid solvent used to dissolve the aramid polymer having high chemical resistance and removed after the spinning causes environmental pollution, it has to be appropriately treated after use. The cost for treating such spent sulfuric acid is not only economical .

Accordingly, the present invention relates to an aramid fiber and a method for producing the same that can prevent the problems caused by the above limitations and disadvantages of the related art.

One aspect of the present invention is to provide an aramid fiber having a high crystallinity and high strength as well as can be prepared without the use of a sulfuric acid solvent by directly using a polymerization solution as a spin doping.

Another aspect of the present invention is to provide a method for producing aramid fibers having a high crystallinity and high strength while producing aramid fibers without using a sulfuric acid solvent by directly using a polymerization solution as a spinning dopant.

In addition to the above-mentioned aspects of the present invention, other features and advantages of the present invention will be described below, or from such description will be clearly understood by those skilled in the art.

In accordance with an aspect of the present invention as described above, it includes a repeating unit of the formula 1 and a repeating unit of the formula (2)

[Formula 1]

[Formula 2]

Wherein R ₁ is —CN, —Cl, —SO ₃ H, or —CF ₃ , and Ar ₁ and Ar ₂ are each independently aromatic hydrocarbons having 1 to 4 benzene rings—, crystallinity of at least 65% and Aramid fibers are provided that have a strength of at least 22 g / denier.

According to another aspect of the invention, the hydrogen of the benzene ring -CN, -Cl, -SO-substituted is substituted with ₃ H, -CF _3, or aromatic diamine (aromatic diamine substituted) and unsubstituted aromatic diamine (non-substituted aromatic diamine in an organic solvent; Next, adding an aromatic diacid halide to the organic solvent to obtain a polymerization solution; Extruding the polymer solution through a spinneret; And forming the filament by allowing the extruded polymerization solution to pass through the coagulation solution, wherein the coagulation solution contains 5 to 20% by weight of the organic solvent and is maintained at 40 to 90 ° C. Provided are methods of making fibers.

The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

According to the present invention, aramid fibers can be produced without the use of a sulfuric acid solvent by directly using a polymerization solution with an irradiance profile. Therefore, the problems such as the complexity of the manufacturing process due to the use of the sulfuric acid solvent, the harmfulness to the human body, and the durability of the manufacturing apparatus can be solved by the present invention. In addition, since aramid fibers can be produced without using a sulfuric acid solvent that causes environmental pollution, a separate process for treating waste sulfuric acid is not necessary, and as a result, manufacturing cost of aramid fibers can be drastically reduced.

In addition, aramid fibers having excellent physical properties comparable to those of conventional aramid fibers prepared by using a sulfuric acid solvent may be prepared by preparing the fibers under optimal spinning and solidification conditions.

Hereinafter, embodiments of the aramid fiber and the manufacturing method thereof according to the present invention will be described in detail.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. It will be apparent to those skilled in the art that variations are possible. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

The aramid fiber of the present invention is a para-aramid fiber having a structure in which benzene rings are linearly connected through an amide group (CONH). Specifically, the aramid fiber of the present invention includes a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

[Formula 1]

[Formula 2]

Wherein R ₁ is —CN, —Cl, —SO ₃ H, or —CF ₃ , and Ar ₁ and Ar ₂ are each independently an aromatic hydrocarbon having 1 to 4 benzene rings.

Alternatively, R ₁ may be -CN and Ar ₁ and Ar ₂ may be phenylene.

The aramid fibers of the present invention have a crystallinity of at least 65% and a strength of at least 22 g / denier.

Hereinafter, a method for producing the aramid fiber of the present invention will be described in detail.

Preparation of Aromatic Polyamide Polymerization Solution

First, inorganic salts are dissolved in an organic solvent.

As the organic solvent, an amide organic solvent, a urea organic solvent, or a mixed organic solvent thereof may be used. Specific examples thereof include N-methyl-2-pyrrolidone (NMP) and N, N-dimethylacetamide. (DMAc), hexamethylphosphoramide (HMPA), N, N, N ', N'-tetramethyl urea (TMU), N, N-dimethylformamide (DMF), or mixtures thereof.

The inorganic salt is added in order to increase the degree of polymerization of the aromatic polyamide. Specific examples thereof include alkali metal halides such as CaCl ₂ , LiCl, NaCl, KCl, LiBr and KBr, or alkaline earth metal halides. These inorganic salts may be added singly or in the form of a mixture of two or more.

Since the inorganic salt has poor solubility in an organic solvent, according to an embodiment of the present invention, water is added to completely dissolve the inorganic salt, and thereafter, the water is removed through a dehydration process.

Inorganic salts function to increase the degree of polymerization of aromatic polyamides produced by the polymerization of aromatic diamines and aromatic dieside halides in organic solvents.

According to the conventional method, the amount of the inorganic salt added to the organic solvent was 6% by weight or more of the solution. That is, in the conventional method, since a sufficient number of inorganic salts functioning to increase the degree of polymerization of aromatic polyamides are used, the aromatic polyamides produced have a high intrinsic viscosity (IV) of greater than 5.0 and have a solid form such as bread crumbs. Have Since the aromatic polyamide would be dissolved in a sulfuric acid solvent to prepare a spinning dope, even if the intrinsic viscosity of the aromatic polyamide polymer exceeded 5.0, there was no problem in the spinning process.

However, in the present invention in which the polymerization solution is spun directly without using a sulfuric acid solvent, the intrinsic viscosity of the aromatic polyamide should not exceed 5.0. Therefore, according to the present invention, the amount of the inorganic salt dissolved in the organic solvent should be 5% by weight or less of the solution. For example, according to one embodiment of the present invention, 2 to 5% by weight of CaCl ₂ is dissolved in an NMP organic solvent. Then, immediately after dissolving CaCl ₂ in the organic solvent, a dehydration process is performed so that the moisture of the organic solvent is 120 ppm or less.

Then, unsubstituted from the group consisting of para-phenylenediamine, 4,4'-diaminodiphenyl, 2,6-naphthalenediamine, 1,5-naphthalenediamine, and 4,4'-diaminobenzanilide A non-substituted aromatic diamine is dissolved in the organic solvent to which the inorganic salt is added. At the same time, by dissolving a substituted aromatic diamine in which the hydrogen of the benzene ring of the aromatic diamine is substituted with -CN, -Cl, -SO ₃ H, or -CF ₃ in the organic solvent to which the inorganic salt is added Prepare a mixed solution. The molar ratio of the substituted aromatic diamine to the unsubstituted aromatic diamine dissolved in the organic solvent containing the inorganic salt is from 9: 1 to 1: 9.

According to an embodiment of the present invention, substituted para-phenylenediamine in which hydrogen of phenylene is substituted with -CN, -Cl, -SO ₃ H, or -CF ₃ in an NMP organic solvent to which CaCl ₂ is added p-phenylenediamine) and para-phenylenediamine were dissolved in a molar ratio of 9: 1 to 1: 9 to prepare a mixed solution.

Subsequently, a predetermined amount of aromatic dieside halide is added to the mixed solution while stirring the mixed solution to prepare a prepolymer. The aromatic dieside halide is terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalenedicarboxylic acid dichloride or 1,5-naphthalenedicarboxylic acid dichloride. According to one embodiment of the invention, the aromatic dieside halide is terephthaloyl dichloride.

Polymerization of an aromatic diamine and an aromatic diacid halide proceeds at a rapid rate with the exothermic reaction. When the polymerization rate is increased as described above, there arises a problem that the difference in degree of polymerization between the finally obtained polymers increases. More specifically, since the polymerization reaction does not proceed simultaneously in the entire mixed solution, the polymer that has first started the polymerization proceeds rapidly to form a long molecular chain, whereas the polymer that has started the polymerization first polymerizes first. There is no choice but to form shorter molecular chains than the polymer from which the reaction was initiated, and the higher the polymerization rate, the greater the difference. As described above, when the difference in degree of polymerization between the finally obtained polymers becomes large, the physical property deviation becomes large, which makes it difficult to realize the desired characteristics. Therefore, it is preferable to minimize the difference in degree of polymerization between the polymers finally obtained by preforming a prepolymer having a molecular chain of a predetermined length through a prepolymerization step, and then performing a polymerization step.

According to one embodiment of the invention, the prepolymerization process is carried out while maintaining the reaction temperature at 0 ~ 45 ℃ in the reactor, the reaction time gives a sufficient polymerization time of about 3 to 15 minutes, the production of aromatic polyamide Only 20-50% of the total amount of the aromatic dieside halide required for is added during the prepolymerization process.

After the prepolymerization process was completed, the temperature was lowered to 0 to 10 ° C., and the remaining amount (50 to 80%) of the aromatic dieside halide was further added to the prepolymer to prepare a polymerization solution including the final aromatic polyamide. do. The aromatic polyamide obtained by the polymerization process includes a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

[Formula 1]

[Formula 2]

Wherein R ₁ is —CN, —Cl, —SO ₃ H, or —CF ₃ , and Ar ₁ and Ar ₂ are each independently an aromatic hydrocarbon having 1 to 4 benzene rings.

According to an embodiment of the present invention, R ₁ is —CN, and Ar ₁ and Ar ₂ are phenylene.

Subsequently, the acid (HCl) generated during the polymerization reaction is neutralized using an alkali compound. The alkali compound for neutralization is selected from the group consisting of alkali metals, carbonates of alkaline earth metals, hydrides of alkaline earth metals, hydroxides of alkaline earth metals, or oxides of alkaline earth metals. Specifically, the alkali compound is NaOH, Li ₂ CO ₃ , CaCO ₃ , LiH, CaH ₂ , LiOH, Ca (OH) ₂ , Li ₂ O or CaO.

According to one embodiment of the present invention, for the neutralization process, CaO equivalent to the acid (HCl) produced by the polymerization reaction is added to the polymerization solution. At the same time, water generated by the neutralization process is removed from the polymerization solution using a vacuum. As the intrinsic viscosity of the aromatic polyamide is increased to 5.0 or more by CaCl ₂ generated together with water in the neutralization with CaO, a polymer solution in which the polymer is uniformly dissolved in an organic solvent is obtained.

According to one embodiment of the present invention, the amount of the organic solvent in the polymerization solution is adjusted so that the concentration of the aromatic polyamide in the polymerization solution is 10 to 20% by weight. If the concentration of the aromatic polyamide in the polymerization solution is out of the above range, the spinning process does not proceed smoothly, the productivity is lowered and the produced aramid fibers do not have satisfactory physical properties.

The polymerization solution prepared as above can be used directly as a spinning dope. That is, according to the present invention, separate processes required in the conventional process to obtain a solid aromatic polyamide, that is, extraction, washing, grinding and drying processes after the polymerization process can be omitted, as well as spinning dope production. In order to dissolve the solid aromatic polyamide in a sulfuric acid solvent may also be omitted.

Therefore, according to the present invention, the productivity can be greatly improved as the polymerization process and the spinning process are carried out simultaneously in the same apparatus, and the complexity of the manufacturing process due to the use of the sulfuric acid solvent, the harmfulness to the human body, and the manufacturing apparatus Problems such as deterioration of durability can be solved. In addition, since aramid fibers can be produced without using a sulfuric acid solvent that causes environmental pollution, a separate process for treating waste sulfuric acid is not necessary, and as a result, manufacturing cost of aramid fibers can be drastically reduced.

Using the polymerization solution Aramid  Manufacture of fibers

The polymerization solution in which the aromatic polyamide is uniformly dissolved in the organic solvent is extruded through a spinneret. The extruded polymerization solution is solidified while passing through a coagulation liquid in a coagulation bath through an air gap to form a filament.

The spinneret has a plurality of capillaries having a diameter of 0.1 mm or less. If the diameter of the capillary formed in the spinneret exceeds 0.1 mm, the molecular orientation of the resulting filament is poor, resulting in a decrease in the strength of the filament.

The air gap may be mainly an air layer or an inert gas layer, the length of the air gap is 0.1 to 15 cm is preferable for improving the physical properties of the filament is produced.

According to the present invention, the coagulating solution further contains 5 to 20% by weight of an organic solvent in addition to water. The organic solvent contained in the coagulation solution is an organic solvent that has actually been used for the preparation of the aromatic polyamide polymerization solution. That is, the organic solvent is N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoamide (HMPA), N, N, N ', N'-tetra Methyl urea (TMU), N, N-dimethylformamide (DMF), or mixtures thereof. Optionally, the coagulant may further comprise alcohols such as ethylene glycol and glycerol.

When the extruded polymerization solution passes through the coagulation solution (that is, when the polymerization solution coagulates), coagulation proceeds as the organic solvent is released from the polymerization solution to form an aromatic polyamide filament.

When the coagulating solution contains only water, the organic solvent is rapidly released from the extruded polymerization solution during the filament forming process, which is a factor of lowering the physical properties, particularly strength of the filament. That is, if the coagulating solution contains only water, it is impossible to produce aramid fibers having a strength of 20 g / denier or more.

According to the present invention, since the coagulating solution further contains 5 to 20% by weight of an organic solvent in addition to water, the organic solvent is released from the extruded polymerization solution at a relatively low rate during the filament forming process. The decrease in strength due to the rapid extraction of the organic solvent can be prevented.

When the content of the organic solvent in the coagulation solution is less than 5% by weight, the organic solvent extraction rate may not be sufficiently lowered. On the other hand, when the content of the organic solvent in the coagulating solution exceeds 20% by weight, the rate of extraction of the organic solvent is too low to increase the probability that a considerable amount of the organic solvent remains in the finally formed filament. The organic solvent remaining in the final filament causes a decrease in crystallinity and strength of the aramid fibers.

As described above, it is important to increase the crystallinity and strength of the aramid fibers in the filament forming process so that all of the organic solvent is removed from the extruded polymerization solution so that the organic solvent substantially does not exist in the final filament. Therefore, according to the present invention, in order to lower the rate at which the organic solvent is extracted from the extruded polymerization solution, the coagulation solution further contains 5 to 20% by weight of an organic solvent in addition to water, and at the same time the filament forming process The coagulation solution is maintained at a high temperature of 40 to 90 ° C. in order to substantially remove all organic solvents in the extruded polymerization solution.

Subsequently, the filament obtained through the coagulation step is washed with water or a mixed solution of water and an alkaline solution.

Then, a drying process is performed to adjust the moisture content remaining in the filament. The drying process may control the time for which the filament is in contact with the heated drying roll, or the moisture content of the filament by adjusting the temperature of the drying roll. The drying rolls are heated by some means, and the drying rolls are preferably at least partly surrounded by heat blocking means in order to prevent excessive heat from being released from the heated rolls and thereby causing heat loss.

Optionally, a heat treatment process may be performed on the dried filaments.

Subsequently, the filament having been dried and heat treated is wound around the branch pipe.

On the other hand, during the spinning process described above, the stretching step of increasing the filament is performed. Since the filament containing the copolymer has relatively low crystallinity, elongation may be high and physical properties such as strength and elastic modulus may be deteriorated. Therefore, the stretching process increases the crystallinity of the filament to improve the strength and elastic modulus of the filament. By controlling the conditions of the stretching process, the elongation of the filament to be produced can be adjusted in various ways depending on the application.

The filament may be adjusted in the draw ratio according to the content and use of the comonomer, the draw ratio may be adjusted in the range of 2 to 13 times. That is, when the content and spinning rate of the comonomer, for example, substituted aromatic diamine, is low, the draw ratio may be set high, and in the reverse case, the draw ratio may be set low. Accordingly, the draw ratio can be properly adjusted within the range of 2 to 13 times in accordance with the content of the comonomer and the spinning speed.

The stretching process may include a wet stretching process. The wet stretching step may be carried out in a coagulating liquid set in a temperature range of 40 to 90 占 폚.

Optionally, the stretching process may include a dry stretching process. The dry drawing process may be performed between the coagulation process and the winding process. That is, the dry drawing process may be performed before winding the filament solidified to the branch pipe to the extent that it can maintain a predetermined shape. For example, the dry drawing process may be performed in a drying process and / or a heat treatment process.

The above-mentioned key drawing process can be performed within a temperature range of 150 to 300 ° C. In the case of solidified filaments, the binding force between the molecular chains is relatively strong, and the fluidity of the molecular chain is relatively poor. Accordingly, the key drawing process for the coagulated filaments is performed at a relatively high temperature of 150 캜 or higher. On the other hand, when the temperature of the film drawing process exceeds 300 ° C, the flowability of the molecular chains increases more than necessary, which may make process control difficult.

Optionally, the stretching process may be performed through two stages of stretching, including both wet stretching and dry stretching. Through such two-stage stretching, the stability of the process can be improved by preventing sudden changes in molecular structure.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It is to be understood, however, that the following examples are intended to assist the understanding of the present invention, and the scope of the present invention is not limited thereby.

Example  One

An N-methyl-2-pyrrolidone (NMP) organic solvent containing 3% by weight of CaCl ₂ was placed in a reactor under a nitrogen atmosphere, and 50 mol% of p-phenylenediamine and cyano-para- 50 mol% of phenylenediamine (cyano-p-phenylenediamine) was added to the reactor and dissolved to prepare a mixed solution.

Subsequently, 40 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a prepolymer, and then 60 mol% of the remaining terephthaloyl dichloride was added to the reactor containing the prepolymer. The polymerization solution containing the aramid polymer was obtained by adding to and completing reaction.

Subsequently, CaO, an alkali compound, was added to the polymerization solution to neutralize the hydrochloric acid generated during the polymerization reaction and to remove water produced by vacuum.

Subsequently, the polymerization solution containing the aramid polymer was heated and the amount of the organic solvent was adjusted to adjust the concentration of the aramid polymer to 16% by weight.

Subsequently, the filaments were formed by extruding the polymerization solution through the spinneret and sequentially passing the air gap and the coagulating solution. The coagulation solution contained 90 wt% water and 10 wt% NMP organic solvent and was maintained at about 50 ° C. At this time, a draw ratio of 5 times was applied.

Then, the filaments were washed with water, and the washed filaments were dried and drawn on a drying roller set at a temperature of 150 ° C. The drawn filaments were heat-treated at 250 ° C and wound up to produce aramid fibers. At this time, the draw ratio in the drying roller was set to be four times.

Example  2

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution contained 95 wt% water and 5 wt% NMP organic solvent.

Example  3

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution contained 80 wt% water and 20 wt% NMP organic solvent.

Example  4

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution was maintained at about 40 ° C.

Example  5

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution was maintained at about 90 ° C.

Comparative example  One

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution contained only water.

Comparative example  2

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution contained 99% by weight of water and 1% by weight of NMP organic solvent.

Comparative example  3

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulating solution contained 75 wt% water and 25 wt% NMP organic solvent.

Comparative example  4

Aramid fibers were prepared in the same manner as in Example 1, except that the coagulation solution was maintained at about 30 ° C.

Tensile strength, elongation, and crystallinity of the aramid fibers obtained by the above examples and comparative examples were measured by the following methods, respectively, and the results are shown in Table 1.

Aramid  Tensile strength and elongation of fiber

The tensile strength and elongation of the aramid fibers were measured by tensile strength and elongation at the breaking point after stretching until a sample of 25 cm in length was broken in an Instron Tester (Instron Engineering Corp., Canton, Mass.) According to ASTM D885 The above process was tested five or more times, and the average value was obtained. At this time, the tensile speed was 300 mm / min, and the initial load was fineness × 1/30 g.

Aramid  Crystallinity of fiber

After cutting the aramid fibers to prepare a sample having a length of 2.5 cm, the aramid fibers were fixed to the sample holder. Subsequently, an X-ray diffraction spectrum of the sample was obtained under the following conditions using an XRD instrument (manufacturer: Rigaku, Japan, model name: D / MAX-RC (12 KW), light source: Cu-Kαradiation). .

-Mode: continuous scan mode

-Scanning angle range: 10-40 °

Scan rate: 2

Peaks appeared in the diffraction angles (2θ) of 20 to 21 degrees and 22 to 23 degrees, respectively. Subsequently, the back ground was set in the diffraction angle (2θ) range of 15-30 °, and then the crystallinity of the sample was obtained through the XRD apparatus.

division Tensile strength (g / d) Shinto (%) Crystallinity (%) Example 1 24.5 5.2 72.4 Example 2 24.2 5.4 70.5 Example 3 25.3 4.8 74.2 Example 4 24.3 5.3 70.8 Example 5 23.5 5.6 68.7 Comparative Example 1 21.5 5.7 62.3 Comparative Example 2 19.8 6.2 60.8 Comparative Example 3 20.6 5.9 61.8 Comparative Example 4 20.5 5.8 61.6

Claims (13)

It includes a repeating unit of formula 1 and a repeating unit of the formula (2)
[Formula 1]

(2)

Wherein R ₁ is —CN, —Cl, —SO ₃ H, or —CF ₃ , and Ar ₁ and Ar ₂ are each independently an aromatic hydrocarbon having 1 to 4 benzene rings;
Aramid fibers characterized by having a crystallinity of at least 65% and a strength of at least 22 g / denier. The method of claim 1,
Wherein R ₁ is —CN, and Ar ₁ and Ar ₂ are phenylene. A substituted aromatic diamine and a non-substituted aromatic diamine in which the hydrogen of the benzene ring is substituted with -CN, -Cl, -SO ₃ H, or -CF ₃ is dissolved in an organic solvent step;
Next, adding an aromatic diacid halide to the organic solvent to obtain a polymerization solution;
Extruding the polymer solution through a spinneret; And
By forming the filament by passing the extruded polymerization solution through the coagulation solution,
The coagulating solution contains 5 to 20% by weight of the organic solvent and the method for producing aramid fibers, characterized in that it is maintained at 40 to 90 ℃. The method of claim 3,
The organic solvent is N-methyl-2-pyrrolidone, N, N-dimethylacetamide, hexamethylphosphoamide, N, N, N ', N'-tetramethyl urea, N, N-dimethylformamide, Or a mixture thereof. The method of claim 3,
Wherein the molar ratio of the substituted aromatic diamine and the unsubstituted aromatic diamine dissolved in the organic solvent is 1: 9 to 9: 1. The method of claim 3,
The substituted aromatic diamine and the unsubstituted aromatic diamine are substituted p-phenylenediamine and non-substituted p-phenylenediamine, respectively,
Wherein said aromatic diacid halide is terephthaloyl dichloride. ≪ RTI ID = 0.0 > 11. < / RTI > The method of claim 3,
Wherein the aromatic diacid halide is added to the organic solvent in two portions at a ratio of 1: 4 to 5: 5. The method of claim 3,
Further comprising the step of dissolving 2 to 5% by weight of CaCl ₂ in the organic solvent before the substituted aromatic diamine and the unsubstituted aromatic diamine are dissolved in the organic solvent. 9. The method of claim 8,
Further comprising the step of dehydrating the organic solvent so that the water content of the organic solvent is 120 ppm or less immediately after dissolving the CaCl ₂ in the organic solvent. The method of claim 3,
Further comprising the step of adding CaO to the polymerization solution to neutralize the HCl generated in the polymerization process before the polymerization solution is extruded. The method of claim 10,
Further comprising the step of adding the CaO to the polymerization solution and removing water from the polymerization solution. The method of claim 11,
Wherein the step of removing the water from the polymerization solution is performed using a vacuum. The method of claim 3,
Further comprising the step of stretching the filaments formed by the coagulation step at a draw ratio of 2 to 13 times.