KR20110035203A - Aramid fiber and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A method for fabricating aramid fiber is provided to prevent discoloration due to long term exposure and to improve tarnish resistance. CONSTITUTION: An aramid fiber contains aromatic polyamide polymers(1) and stabilizing agent(2). The aromatic polyamide polymers contain aromatic diamine and aromatic diacid halide. The stabilizing agent is used for preventing tarnishing and is distributed between changes of the polyamide polymers.

Description

Aramid Fiber and Method for Manufacturing the Same

The present invention relates to an aramid fiber and a method for manufacturing the same, and more particularly, to an aramid fiber having an improved discoloration resistance so as not to discolor even when exposed to external environment such as sunlight, air, moisture, etc. for a long time will be.

Generally, wholly aromatic polyamide fibers, collectively referred to as aramid fibers, include para-aramid fibers and meta-aramid fibers having a structure in which the benzene rings are connected linearly through an amide group (CONH). Para-aramid fiber has excellent properties such as high strength, high elasticity, and low shrinkage. It is a thin thread of about 5mm thick and has a strong strength enough to lift 2 tons of cars. It is used in various industries in the high-tech industry. In addition, aramid fibers are carbonized at 500 ° C or higher, and thus are attracting attention in fields requiring high heat resistance.

Aramid fiber is a process for producing a wholly aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic diacid halide in a polymerization solvent containing N-methyl-2-pyrrolidone, dissolving this polymer in a concentrated sulfuric acid solvent to prepare a spinning dope After the step of spinning the spinning dope through the spinneret to pass through the non-coagulant fluid and coagulation bath sequentially to produce a filament, and the step of washing the filament, and drying and heat treatment .

The conventional aramid fibers prepared as described above have a light yellow color initially, but have a problem of discoloration when exposed to external environments such as sunlight, air, and moisture for a long time. Such discoloration of aramid fibers is known not only to lower the customer attraction of the aramid fibers, but also to be accompanied by a decrease in physical properties, particularly strength of the aramid fibers.

On the other hand, the aromatic diamine used to prepare the wholly aromatic polyamide polymer is highly reactive and easily discolored when exposed to the external environment.Aramid fiber, the final product obtained from such discolored aromatic diamine, has poor physical properties and deteriorates customer reliability. Let's do it.

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.

The present invention is derived to solve the above problems, the advantage of the present invention is that the aramid fibers having improved discoloration resistance and its discoloration so that the discoloration does not become well even when exposed to external environment such as sunlight, air, moisture, etc. for a long time To provide a way.

Further features and advantages of the invention will be described below, and in part will be apparent from such techniques. Alternatively, other features and advantages of the present invention may be learned from the practice of the present invention.

In order to achieve the above advantages, and according to the object of the present invention, in the aramid fibers prepared by spinning an aromatic polyamide polymer prepared by polymerizing an aromatic diamine and an aromatic diex halide, the aramid fibers to prevent discoloration There is provided an aramid fiber comprising a stabilizer for.

In another aspect of the invention, a step of polymerizing an aromatic diamine and an aromatic diacid halide to prepare an aromatic polyamide polymer; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; And preparing a filament by spinning the spinning dope, wherein preparing the aromatic polyamide polymer is provided by adding a stabilizer to the aromatic diamine. .

In another aspect of the present invention, there is provided a method for preparing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic diacid halide; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; Preparing an aramid filament by spinning the spinning dope; And it provides a method for producing aramid fiber comprising the step of treating a stabilizer to the aramid filament.

According to the aramid fiber and the manufacturing method thereof according to the present invention, while the aramid fiber satisfies the physical properties required in the industry, it can maintain its intrinsic color even when exposed to the external environment such as sunlight, air, moisture and the like for a long time. Therefore, it is possible to prevent the reduction in customer attraction force due to discoloration and strength reduction of the aramid fibers.

Aromatic diamines used to prepare aromatic polyamide polymers are susceptible to discoloration by reacting sensitively to air and the like, and aramid fibers prepared using such discolored aromatic diamines have a number of defects. Aramid fibers having such a number of drawbacks are deteriorated in physical properties, resulting in a decrease in purchasing power of customers due to discoloration of aramid fibers.

Aramid fibers also contain a number of amine or acid end groups. In particular, amine end groups, due to their sensitive reactivity, aramid fibers easily change when exposed to external environments such as sunlight, air, moisture, and the like. The discolored aramid fibers have a sharp drop in physical properties and have a dark color.

Accordingly, the present invention focuses on providing a means for preventing discoloration of the aromatic amine which is a raw material of aramid fibers, or preventing discoloration and a decrease in strength when the manufactured aramid fibers are stored or used for a long time.

As described above, since aromatic diamine is very reactive, it can easily react with other materials and be mutated. The aromatic diamine thus modified has different reactivity with the undiluted aromatic diamine, and the aromatic polyamide polymer (1) prepared therefrom has a non-uniform degree of polymerization. Thus, the aramid fiber manufactured from the aromatic polyamide polymer (1) whose polymerization degree is nonuniform is low in strength and elastic modulus. In addition, aramid fibers made from discolored aromatic diamines become dark yellow, which lowers the purchasing power of the customer. On the other hand, aramid fibers having amine end groups easily discolor when exposed to the external environment.

Therefore, in order to prevent discoloration of such aromatic diamine or aramid fibers, the present invention adds a stabilizer (2) to the aromatic diamine or aramid fibers. Such added stabilizer (2) may be an organophosphorus, phenolic, hindered amine stabilizer (2). Among the organophosphorus stabilizers (2), phosphine stabilizers (2) may be used to stabilize the aromatic diamine.

Specific examples of the phosphine stabilizer (2) include ethyl phosphine, n-butyl phosphine, phenyl phosphine, diethyl phosphine, di (n-butyl) phosphine, diphenylphosphine, triethyl phosphine , Tri (n-butyl) phosphine, tri (cyclohexyl) phosphine, triphenylphosphine and the like.

The aromatic diamine to which the stabilizer 2 is added is protected even if exposed to air, moisture, or the like, since the stabilizer 2 first reacts with the foreign substance, thereby protecting the aromatic diamine from the foreign substance, thereby preventing discoloration of the aromatic diamine. .

In addition, the aramid fiber to which the stabilizer (2) is added can prevent discoloration and deterioration of physical properties of the aramid fiber because the stabilizer (2) protects the amine end group from the external material even when exposed to the external environment for a long time.

1 is a schematic cross-sectional view of an aramid fiber according to an embodiment of the present invention. As shown in FIG. 1, the stabilizer 2 is distributed evenly in the whole inside of the aramid fiber of this invention. On the other hand, Figure 2 is a schematic view showing a cross section of the aramid fiber according to another embodiment of the present invention. As shown in Fig. 2, the produced aramid fibers have the stabilizer 2 partially distributed only outside.

When the aramid fibers are prepared by adding the stabilizer (2) in the polymerization step, the aramid fibers as shown in FIG. 1 can be obtained, and when the stabilizer (2) is treated after the filaments are formed, the aramid fibers as shown in FIG. 2 can be obtained. have. This is because when the aromatic polyamide polymer is changed into filaments, the filament internal structure becomes dense and the stabilizer 2 cannot easily penetrate into the filament. In the aramid fiber as shown in Figure 2 stabilizer (2) is distributed outside the aramid fiber, the fastness may be lowered, and thus the color retention may be lowered when used for a long time. In addition, the aramid fiber as shown in Figure 2 may not be enough to protect the end group because of the low content of the stabilizer (2) may be inferior discoloration resistance.

On the other hand, the aramid fibers in which the stabilizer 2 is evenly distributed throughout the interior as shown in FIG. 1 may have more excellent fastness and discoloration resistance.

Since the aramid fibers of the present invention are distributed between the molecular chains and the molecular chains without the stabilizer (2) being added to the aromatic polyamide polymer (1) as airborne materials, the aramid fibers do not degrade the alignment crystals of the polymer, and thus have excellent strength and Elastic modulus can be maintained.

It is preferable that the said aramid fiber contains the stabilizer (2) of 20-10,000 ppm. If the content of the stabilizer (2) is less than 20 ppm, the aramid fibers are easily discolored as the terminal groups are not sufficiently protected from the external material, and as a result, the physical properties of the aramid fibers are drastically reduced. On the other hand, when the content of the stabilizer (2) exceeds 10,000ppm, the discoloration prevention performance is excellent, but the stabilizer (2) acts as a defect (defect) as the crystal orientation of the molecular chain is lowered, the strength of the aramid fiber is lowered do.

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

First, an inorganic salt is added to an organic solvent to prepare a polymerization 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), N, and N'-dimethylacetate. Amide (DMAc), hexamethylphosphoramide (HMPA), N, N, N ', N'-tetramethyl urea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof.

The inorganic salt is added to increase the degree of polymerization of the aromatic polyamide, and specific examples thereof include halogenated alkali metal salts or halogenated alkaline earth metal salts such as CaCl ₂ , LiCl, NaCl, KCl, LiBr, and KBr. Salts may be added alone or in the form of a mixture of two or more. As the amount of the inorganic salt increases, the degree of polymerization of the aromatic polyamide increases, but when the inorganic salt is added in an excessive amount, there may be an inorganic salt that does not dissolve. Thus, the inorganic salt is 10% by weight or less based on the total amount of the polymerization solvent. It is preferable that it is the range of. Since the inorganic salt has poor solubility in organic solvents, the final polymerization solvent can be prepared by completely dissolving the inorganic salts by adding water and then removing the water through a dehydration process.

Next, a mixed solution is prepared by dissolving the aromatic diamine to which the predetermined stabilizer (2) is added to the prepared polymerization solvent. The added stabilizer (2) may be an organophosphorus, phenolic, hindered amine stabilizer (2), the organophosphorus stabilizer (2) may be a phosphine stabilizer (2) However, the present invention is not limited thereto.

Next, while stirring the mixed solution, a predetermined amount of aromatic diacid halide is added to the mixed solution and prepolymerized.

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 wholly aromatic polyamide polymer It is preferable to add only 20 to 40% of the total amount of the aromatic diacid halide required for the preparation during the prepolymerization process.

After completion of the prepolymerization process, the temperature is lowered to 0 to 10 ° C. and the aromatic diexide halide is further added to the prepolymer to prepare a final polymer. Specific examples of the aromatic polyamide polymer (1) obtained by the polymerization step include poly (paraphenylene terephthal-amide: PPD-T), poly (4,4'-benzanilide terephthalamide), and poly (paraphenylene). -4,4'-biphenylene-dicarboxylic acid amide) or poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide).

Subsequently, the acid produced during the polymerization reaction is neutralized with an alkali compound. The alkali compound is an alkali metal of NaOH, Li ₂ CO ₃ , CaCO ₃ , LiH, CaH ₂ , LiOH, Ca (OH) ₂ , Li ₂ O or CaO, carbonate of alkaline earth metal, hydride of alkaline earth metal, hydroxide of alkaline earth metal Or an oxide of an alkaline earth metal.

When an inorganic alkali compound is added to an aromatic polyamide solution in a strong acid state containing a large amount of hydrochloric acid, the reaction rapidly reacts with hydrochloric acid, so that neutralization proceeds rapidly. The reaction rate is drastically reduced and the inorganic alkali compound remains in the neutralization solution in an unreacted state. This causes a problem that the insoluble inorganic alkali compound must be filtered through a filter after the neutralization is completed. Therefore, in order to prevent the formation of insoluble foreign matter in the aromatic polyamide solution, the neutralization process may be carried out at several times.

Subsequently, the neutralization process is completed to grind the aromatic polyamide polymer (1) from which the acid is removed. If the particle size of the polymer is too large in the extraction process described later, the polymerization solvent extraction process takes a lot of time and the polymerization solvent extraction efficiency is lowered, so that the grinding process is performed to reduce the particle size of the polymer before the extraction process.

Subsequently, the polymerization solvent is extracted from the pulverized aromatic polyamide polymer (1). Since the polymerization solvent used for the polymerization step is contained in the aromatic polyamide polymer (1) obtained by the polymerization, such a polymerization solvent must be extracted from the polymer, and the extracted polymerization solvent can be reused in the polymerization step. This extraction process is most effective and economical to perform with water. The extraction process may be performed by installing a filter in a bath having a discharge port, placing a polymer in the form of a crumb on the filter, and then pouring water to discharge the polymerization solvent contained in the polymer together with water to the discharge port.

Next, water remaining after the extraction step is dehydrated, and then the aromatic polyamide polymer (1) is completed through a drying step.

The polyamide polymer is then dissolved in concentrated sulfuric acid solvent having a concentration of 97-102% to produce spinning dope. Alternatively, chlorosulfuric acid, fluorosulfuric acid, or the like may be used instead of the concentrated sulfuric acid.

After spinning the spin dope using a spinneret, a filament is formed by coagulating in a coagulation bath in which a coagulant is received through an air gap. 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. 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 coagulating solution may be added sulfuric acid to water, ethylene glycol, glycerol, alcohol, or a mixture thereof, and is maintained at -20 to +90 ℃. When the radiation passed through the spinneret passes through the coagulating solution, the sulfuric acid in the emission is removed and filaments are formed. When sulfuric acid is rapidly removed from the surface, the surface is solidified before the sulfuric acid contained therein escapes. Since the problem of the uniformity of the filament may be lowered, sulfuric acid is added to the coagulating solution in order to prevent sulfuric acid from escaping rapidly from the surface of the radiant.

Next, sulfuric acid remaining in the obtained filament is removed. Sulfuric acid used in the manufacture of the spinning dope can remain but is not completely removed, although most of the emissions are passed through the coagulation bath. Moreover, when sulfuric acid is added to the coagulation liquid of a coagulation tank in order to make sulfuric acid escape | emit uniformly from a effluent, there is a high possibility that sulfuric acid will remain in the filament obtained. Since the amount of sulfuric acid remaining in the filament may adversely affect the aramid fiber properties no matter how small the amount, it is very important to completely remove the sulfuric acid remaining in the filament. Sulfuric acid remaining in the filament may be removed through a washing process using water or a mixed solution of water and an alkaline solution. The washing process may be carried out in a multi-step process, for example, after first washing the filament containing sulfuric acid with 0.3 to 1.3% of an aqueous caustic solution (water solution), 0.01 to 0.1% of a thinner caustic aqueous solution You can do a second flush.

The washed aramid filaments are dried. The moisture content of the filament can be controlled by adjusting the time for which the filament is in contact with the heated drying roll or by controlling 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.

Subsequently, the dried filament is wound on a branch pipe. Spinning speed is 300 to 1500 m / min.

The aramid fibers produced by adding the stabilizer (2) in the polymerization step as described above, the stabilizer (1) is evenly distributed in the aramid fibers as shown in Figure 1, thereby satisfying the distribution nonuniformity of the stabilizer of the aramid fibers as shown in the following formula do. That is, as the stabilizer 1 is evenly distributed inside the aramid fiber, the aramid fibers produced as described above have a low distribution nonuniformity of the stabilizer.

for a≥b 0≤ [│a-b│ × 100] / a≤50, for b> a 0≤ [│a-b│ × 100] / b≤50

(Where a is the average number of stabilizers per unit area at the center and b is the average number of stabilizers per unit area at the outside)

Therefore, even if the aramid fiber as shown in Figure 1 is exposed to an external environment such as light, moisture, air for a long time, the end group is protected by the stabilizer (2) to prevent discoloration of the aramid fibers. In addition, by preventing discoloration of the aromatic diamine, the produced aramid fibers not only have excellent strength and modulus of elasticity, but also have little color, thereby improving customer purchasing power.

Alternatively, the present invention may process the stabilizer (1) on the filament after the step of forming the aromatic polyamide polymer into filaments, instead of adding the stabilizer (2) in the polymerization step to produce aramid fibers.

The process of treating the stabilizer (1) to the filament may be carried out by treating the stabilizer (1) to the filament before drying and winding after the spinning dope is spun.

In addition, a stabilizer may be treated on the aramid fibers prepared by a conventional method using a separate stabilizer (1) treatment device, and after the aramid fibers prepared by the conventional method is made of a fabric, a stabilizer ( 1) can be processed, but is not necessarily limited thereto.

The method of imparting the stabilizer (1) to the filament may be carried out through various conventional methods. That is, the stabilizer 1 may be added to the filament using a dipping method, a spray method, or the like.

In the aramid fibers prepared as described above, as shown in Fig. 2, a large number of stabilizers 1 are distributed outside the aramid fibers. Therefore, the aramid fibers as shown in FIG. 2 may be slightly inferior in color resistance and physical properties compared to the aramid fibers shown in FIG. 1.

When the aramid fibers prepared as described above are used in an optical cable or the like, the optical cable or the like can be safely reported for a long time. In addition, when the aramid fibers of the present invention is used in bulletproof products, bulletproof performance can be maintained for a long time, thereby improving the customer's confidence.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, the following examples are only intended to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

1. Addition of stabilizers in the polymerization stage

Example  One

Para-phenylenediamine 5.00 with 1,000 ppm of tri-phenylphosphine as stabilizer (2) was added to 100 ml of N-methyl-2-pyrrolidone (NMP) with 100 wt% of CaCl ₂ polymerized solvent. g was dissolved to prepare a mixed solution. Prepolymer was prepared by adding 3.18 g of terephthaloyl dichloride to the mixed solution and reacting at a rotational force of 500 rpm for 6 minutes. To this prepolymer, an additional 5.61 g of terephthaloyl dichloride was added and reacted for 15 minutes to prepare a poly (paraphenylene terephthal-amide: PPD-T) polymer, which was dissolved in 98% concentrated sulfuric acid solvent to form a spinning dope. (spinning dope) was prepared.

After the spinning dope was spun using spinneret, the aramid filament was obtained by solidifying in a coagulation bath through an air gap, and the aramid filament was washed with an alkaline solution.

The washed aramid filament was dried at a temperature of 150 ° C. for 3 seconds and then wound in a bobbin to complete the aramid fiber.

Example  2

In Example 1 described above, aramid fibers were prepared in the same manner as in Example 1, except that Irganox 1010 (CIBA Chem.), A phenolic compound, was used instead of triphenylphosphine as the stabilizer (2).

Example  3

In Example 1 described above, aramid fibers in the same manner as in Example 1 except for using a hindered amine-based Tinuvin-292 (CIBA Chem.) Instead of using triphenylphosphine as the stabilizer (2) Prepared.

Example  4 to 9

In Example 1 described above, aramid fibers were prepared in the same manner as in Example 1 except that the stabilizer (2) was added in an amount of 10 ppm, 500 ppm, 3000 ppm, 6000 ppm, 9000 ppm, and 12000 ppm, respectively, to para-phenylenediamine. It was.

Comparative example

In Example 1 described above, aramid fibers were prepared in the same manner as in Example 1 except for using para-phenylenediamine to which the stabilizer (2) was not added.

For each of the aramid fibers obtained by the above Examples 1 to 9 and Comparative Examples, color retention, strength retention, and elasticity retention were measured by the following method and the results are shown in Table 1.

Color retention (△ L) measurement

The color of the aramid fiber is defined as L value measured using KURABO's COLOR-7X, and “color change” refers to the aramid fiber with initial color L1 of Black Panel Temperature (65 + 3 ° C), Exposure Light Source (Xenon). -Arc), Irradiance (0.35W / m ² @ 340nm), Exposure Cycle (102min of Light only / 18min Light and Water Spray) under the conditions of the color change that occurs when left for 24h (△ L) was measured.

Strength retention (%) and Modulus  % Retention

The strength (g / d) and modulus (g / d) of the aramid fibers after standing and before standing under conditions to be described later are measured when a 25 cm long sample is broken in an Instron Engineering Corp (Canton, Mass). The strength (g) of the sample was measured and then divided by the denier of the sample to obtain the strength and elastic modulus of the sample. At this time, the tensile speed was 300 mm / min, and the super load was fineness x 1/30 g. At this time, five aramid fiber samples were tested and obtained by the average value.

The standing conditions of the aramid fibers prepared from the examples and the comparative examples were 1008 hours at a temperature of 45 ℃ in a Q-UV apparatus (CLEVELAND, 26200 First).

The strength and elastic modulus values before and after the standing measured by the method described above were calculated using the following equation.

Strength retention (%) = (strength after standing / strength before standing) × 100

Elastic modulus retention rate (%) = (elastic modulus after standing / elastic modulus before standing) × 100

division Color Retention Rate (△ L) Strength before standing (g / d) Strength retention rate (%) Elastic modulus before leaving (g / d) Elastic modulus retention rate (%) Example 1 -13.0 24.3 73.5 778 96.3 Example 2 -17.5 23.5 70.2 766 91.1 Example 3 -16.3 23.9 72.3 785 92.5 Example 4 -14.3 23.7 71.7 781 90.5 Example 5 -14.0 23.9 72.4 793 93.2 Example 6 -13.9 24.3 71.9 753 95.5 Example 7 -14.1 24.1 70.8 788 97.1 Example 8 -14.3 24.0 73.1 762 93.2 Example 9 -14.9 23.6 72.9 770 94.6 Comparative example -19.0 24.2 72.1 762 89.7

2. Addition of stabilizer in the step after aramid filament formation

Example  10

Example 1, except that the stabilizer (2) is added to the para-phenylenediamine, except that the stabilizer (2) is imparted by a dipping method to the aramid fibers prepared by a conventional method. Aramid fibers were prepared by the same method as described above. At this time, the dipping method was carried out in the state of stabilizer concentration of 10% by weight, impregnation time 3 seconds, drying temperature 150 ℃.

For each of the aramid fibers obtained in Example 1 and Example 10, the dispersion nonuniformity of the stabilizer was measured by the following method, and the results are shown in Table 2.

Distribution of Stabilizers in Aramid Fibers Non-uniformity  Measure

Through the mapping method using the EDX (Hitachi, L4300) device, the shape of the stabilizer 2 distributed in the cross section f of the aramid monofilament (mono filament) could be illustrated as shown in FIG. 3. As shown in FIG. 3, after showing the inscribed circle C1 of the cross section of the aramid monofilament, an imaginary circle having three quarters of the inscribed circle radius r with respect to the center C of the inscribed circle. (C2) is shown. The inside including the imaginary circle C2 is the central portion, and the outside of the central portion is the outer portion. The value obtained by dividing the number of stabilizers in the center part by the area S2 of the center part is b, and the value obtained by dividing the number of stabilizers in the outer part part by the area S1 part of the outer part part is a. Next, the distribution nonuniformity of the stabilizer of aramid fiber is measured using the following formula.

for a≥b 0≤ [│a-b│ × 100] / a≤50, for b> a 0≤ [│a-b│ × 100] / b≤50

division Stabilizer treatment stage Uniformity of distribution of stabilizer Example 1 Polymerization stage 33.5 Example 10 Post-processing stage 100

1 is a schematic cross-sectional view of an aramid fiber according to an embodiment of the present invention.

2 is a schematic cross-sectional view of an aramid fiber according to another embodiment of the present invention.

It is a schematic diagram for demonstrating the measuring method of the distribution nonuniformity of the stabilizer distributed in the cross section of the aramid monofilament of this invention.

<Description of Main Parts of Drawings>

1: aromatic polyamide polymer 2: stabilizer

Claims (8)

An aramid fiber prepared by spinning an aromatic polyamide polymer prepared by polymerizing an aromatic diamine and an aromatic diacid halide, wherein the aramid fiber comprises a stabilizer for preventing discoloration. The method of claim 1, The stabilizer is aramid fiber, characterized in that distributed between the molecular chain and the molecular chain of the aromatic polyamide polymer. The method of claim 1, The aramid fibers are aramid fibers, characterized in that the distribution nonuniformity of the stabilizer satisfies the following formula. for a≥b 0≤ [│a-b│ × 100] / a≤50, for b> a 0≤ [│a-b│ × 100] / b≤50 (Where a is the average number of stabilizers per unit area at the center and b is the average number of stabilizers per unit area at the outside) The method of claim 1, The stabilizer is an aramid fiber, characterized in that the organophosphorus, phenolic, or hindered amine stabilizer. The method of claim 1, The content of the stabilizer is aramid fiber, characterized in that 20 to 10,000ppm. Polymerizing the aromatic diamine and the aromatic diacid halide to prepare an aromatic polyamide polymer; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; And Manufacturing a filament by spinning the spinning dope, Preparing the aromatic polyamide polymer comprises adding a stabilizer to the aromatic diamine. Polymerizing the aromatic diamine and the aromatic diacid halide to prepare an aromatic polyamide polymer; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; Preparing an aramid filament by spinning the spinning dope; And Method for producing aramid fibers comprising the step of treating a stabilizer to the aramid filament. The method according to claim 6 or 7, The stabilizer is a process for producing aramid fibers, characterized in that the organophosphorus, phenolic or hindered amine stabilizer.

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