KR101386379B1 - Aramid Fiber, method of manufacturing Aramid Fiber, bulletproof fabric, and method of manufacturing bulletproof fabric - Google Patents

Abstract

The present invention provides a process for preparing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic dieside halide; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope and then spinning to produce a filament; And it comprises a step of drying the filament, the step of drying the filament is the first drying step to adjust the moisture content of the filament is in the range of 25% to 35%, the moisture content of the filament is 10% to 15% It comprises a second drying step to adjust the range, wherein the tension applied to the filament during the second drying step is less than the tension applied to the filament during the first drying process, the method of producing aramid fibers Aramid fibers produced by the present invention, and a ballistic fabric using the aramid fibers, and a method for producing the same,

According to the present invention, it is possible to obtain aramid fibers having improved flexibility by optimizing the drying process of the filaments subjected to the spinning process in the process of producing aramid fibers. Further, by manufacturing the armor fabric using such aramid fibers, The bullet-proof characteristic of the bullet-proof bulb is improved.

Aramid fiber, bulletproof,

Description

TECHNICAL FIELD The present invention relates to a aramid fiber, a method of manufacturing the aramid fiber, a method of manufacturing the same, and a method of manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fabric for bulletproof protection, and more particularly to a fabric for bulletproofing using aramid fibers.

Bulletproof fabrics are used in various armor products such as bulletproof vests, bulletproof helmets, and bulletproof plates. Bulletproof products are products for protecting the human body from the waves of bullets and shells. The bulletproof performance of the bulletproof articles depends on the bulletproof performance of the bulletproof fabric, and the bulletproof performance of the bulletproof fabric Organizational structure, and so on.

Background Art [0002] A yarn used in a fabric for bulletproofing generally has high strength properties, and aramid fibers are known as yarn having such characteristics.

The aramid fiber is an aromatic polyamide fiber, which comprises a step of producing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic diacid chloride in a polymerization solvent, a step of preparing a spinning dope by dissolving the aromatic polyamide polymer in a solvent And a process of spinning the spinning dope through a spinneret and solidifying the spinning material to produce filaments.

When the aramid fiber is used to produce a bulletproof fabric, the bullet-proof fabric obtained by the high strength properties of the aramid fiber has high strength properties, but the desired bulletproof characteristics have not yet been obtained.

More specifically, when the bullet collides with the bulletproof fabric, the yarn constituting the fabric must not be easily broken by the impact, and the impact applied to the human body is minimized only when the impact is absorbed easily.

The aramid fiber is not easily broken due to the collision of the bullets because of its excellent crystallinity and high strength, but the flexibility of the fiber is insufficient and the effect of absorbing the impact of the bullet is somewhat deteriorated. For this reason, The desired bulletproof property has not yet been obtained in the used armor fabric.

The present invention aims to provide an aramid fiber capable of improving the flexibility of an aramid fiber, thereby easily absorbing the impact of the bullet, thereby improving the bulletproofing property, a method of manufacturing the same, and a method of manufacturing the same.

The present inventors have studied to improve the flexibility of the aramid fiber, and confirmed that the flexibility of the aramid fiber can be improved when the drying process of the filament after the spinning process is optimized.

That is, in the process of drying the filament formed through the spinning process, if the tension is slightly relaxed compared to the existing tension in the state in which the predetermined moisture is contained in the filament, it is possible to obtain aramid fibers with improved flexibility In more detail, during the drying process until the moisture content of the filament is in the range of 25 to 35%, a tension of a predetermined size is applied to the filament, and the moisture content of the filament thereafter is in the range of 10% to 15%. In the drying process up to the present invention was confirmed that the flexibility of the aramid fibers can be enhanced by applying a tension of a size smaller than the initial applied tension.

The concrete means for solving the present invention is as follows.

The present invention provides a process for preparing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic dieside halide; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope and then spinning to produce a filament; And comprising the step of drying the filament, the step of drying the filament is the first drying step to adjust the moisture content of the filament is in the range of 25% to 35%, the moisture content of the filament is 10% to 15% It comprises a second drying step to adjust the range, the tension applied to the filament during the second drying process provides a method for producing aramid fibers, characterized in that less than the tension applied to the filament during the first drying process. .

Herein, the tension applied to the filament during the first drying process may range from 0.1 to 0.5 g / d, and the tension applied to the filament during the second drying process may range from 0.05 to 0.1 g / d.

After the second drying process, a third drying process may be performed such that the moisture content of the filament is 5% or more and less than 10%, wherein the tension applied to the filament during the third drying process is 0.1 to 0.5 g / d range.

The process of drying the filament is made of a process of winding the filament on a drying roll heated to a predetermined temperature, in this case, by adjusting the number and temperature of the drying roll to adjust the moisture content of the filament, the rotational speed of the drying roll By adjusting the tension applied to the filament can be adjusted.

The present invention provides an aramid fiber characterized in that an amide bond is bonded between the aromatic rings, the strong retention is 80% or more, and the storage elastic retention is 90% or more.

The present invention is a process for producing aramid fibers according to the above-described method; And it provides a method for producing a bulletproof fabric comprising a step of weaving the aramid fibers as warp and weft.

The present invention provides a ballistic fabric, characterized in that the warp and weft yarn is made of aramid fibers, wherein the aramid fibers have a strong retention of 80% or more and a storage elastic retention of 90% or more.

The bulletproof fabric may have a bulletproof performance (V0) of 436 m / s or higher on the basis of NIJ level IIIA when 30 to 38 layers are overlapped.

According to the present invention as described above, the following effects can be obtained.

The present invention can obtain aramid fibers with improved flexibility by optimizing the drying process of the filament formed through the spinning process. In addition, by producing a bulletproof fabric using such aramid fibers, there is an effect that the bulletproof characteristics of the bulletproof fabric is improved.

Hereinafter, preferred embodiments of the present invention will be described in detail.

1. Preparation of aromatic polyamide polymer

1) First, a polymerization solvent is prepared.

The polymerization solvent is prepared by adding an inorganic salt to 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), N, and N'-dimethyl. Acetamide (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 polymerization degree 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. The salts may be added alone or in the form of a mixture of two or more. As the addition amount of the inorganic salt increases, the degree of polymerization of the aromatic polyamide increases. However, since an inorganic salt which does not dissolve when the inorganic salt is added in an excessive amount may be present, the inorganic salt may be present in an amount of 10% .

2) Next, a mixed solution is prepared by dissolving the aromatic diamine in the polymerization solvent.

Specific examples of the aromatic diamine include para-phenylenediamine, 4,4'-diaminobiphenyl, 2,6-naphthalenediamine, 1,5-naphthalenediamine or 4,4'-diaminobenzanilide However, the present invention is not limited thereto.

3) Next, a predetermined amount of aromatic di-halide halide is added to the mixed solution while stirring the mixed solution to pre-polymerize.

In the polymerization of the aromatic diamine and the aromatic dieside halide, the reaction proceeds at a high rate with exotherm. When the polymerization rate is high, a difference in the degree of polymerization between the finally obtained polymers occurs. More specifically, since the polymerization reaction does not proceed at the same time in the entire mixed solution, the polymer in which the polymerization reaction is initiated first rapidly undergoes a polymerization reaction to form a long molecular chain, The shorter the molecular chain, the faster the polymerization rate becomes. 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.

Thus, through the prepolymerization process, a polymer having a molecular chain of a predetermined length is formed in advance, and then a polymerization process is performed to minimize the difference in degree of polymerization between the finally obtained polymers.

Specific examples of the aromatic diacid halide include terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalene dicarboxylic acid dichloride and 1,5-naphthalene dicarboxylic acid dichloride, But is not limited thereto.

4) Then, after completion of the prepolymerization step, the remaining amount of the aromatic diacid halide is added to the mixed solution while stirring at 0 to 30 ° C for polymerization.

Since the aromatic diacid halide reacts with the aromatic diamine in a 1: 1 molar ratio in the production of the aromatic polyamide, the aromatic diamine and the aromatic diacid halide can be added at the same molar ratio.

Specific examples of the aromatic polyamide polymer obtained by the polymerization step include poly (paraphenylene terephthalamide: PPD-T), poly (4,4'-benzanilide terephthalamide), poly (paraphenylene-4, 4'-biphenylene-dicarboxylic acid amide) or poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide).

5) Next, an alkali compound is added to the obtained aromatic polyamide solution to neutralize the acid generated during the polymerization reaction.

When the polymerization reaction proceeds, an acid such as hydrochloric acid is generated. Such an acid causes problems such as corrosion of the polymerization apparatus. Therefore, an inorganic alkali compound or an organic alkali compound is added during or after the polymerization reaction, .

At this time, since the aromatic polyamide obtained through the polymerization reaction exists in the form of bread crumbs, the flowability of the aromatic polyamide solution is poor. Therefore, in order to improve the flowability, it is preferable to add water to the aromatic polyamide solution to prepare a slurry, and then carry out the subsequent step. For this purpose, water is added to the aromatic polyamide solution in an aromatic polyamide solution, The process can be carried out.

The inorganic alkaline compound may be at least one selected from the group consisting of alkaline metals such as NaOH, Li ₂ CO ₃ , CaCO ₃ , LiH, CaH ₂ , LiOH, Ca (OH) ₂ , Li ₂ O or CaO, carbonates of alkaline earth metals, hydrides of alkaline earth metals, Hydroxide, or an oxide of an alkaline earth metal.

6) Next, the aromatic polyamide polymer from which the acid has been removed is pulverized by completing the neutralization process.

If the particle size of the polymer is too large in the extraction process to be described later, it takes a long time for the polymerization solvent extraction process and the polymerization solvent extraction efficiency is lowered. Therefore, the pulverization process is performed in order to reduce the particle size of the polymer before the extraction process.

7) Next, the polymerization solvent contained in the aromatic polyamide polymer is extracted to remove the polymerization solvent from the polymer.

Since the aromatic polyamide polymer obtained by the polymerization contains the polymerization solvent used for the polymerization process, such a polymerization solvent must be extracted from the polymer, and the extracted polymerization solvent is reused in the polymerization process.

8) Next, water remaining after the extraction process is dewatered, and then drying is completed to prepare the aromatic polyamide polymer.

2. Aramid  Manufacture of fibers

1) First, a spinning dope is prepared by dissolving the aromatic polyamide polymer produced by the above method in a solvent.

The solvent may be a concentrated sulfuric acid solvent having a concentration of 97 to 100%. In place of the concentrated sulfuric acid, chlorosulfuric acid, fluorosulfuric acid, and the like may also be used.

2) Next, filaments are formed by spinning the spin dope using a spinneret and then solidifying it in a coagulation bath 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 coagulation bath is located at a lower portion of the spinneret, and a coagulation bath is stored in the lower portion of the coagulation bath. Therefore, the radiation passing through the capillary of the spinneret goes down while the air gap and the coagulating solution sequentially pass to form a filament. The filament is discharged through the coagulation tube under the coagulation bath.

In addition, the coagulation tube is formed with a jet device (jet device) can be injected to the filament passing through the coagulation tube. The injector has a plurality of jet openings and injects the coagulation liquid from the plurality of injection openings toward the filament.

The coagulating solution may be added with sulfuric acid to water, ethylene glycol, glycerol, alcohol, or a mixture thereof. 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. In order to solve this problem, sulfuric acid is added to form a coagulation solution.

3) Next, the sulfuric acid remaining in the obtained filament is removed.

Since a sulfuric acid solution is used in the preparation of the radial dope, sulfuric acid may remain in the filament produced by the spinning process. The sulfuric acid remaining in the filament can be removed through a washing process using water or a mixed solution of water and an alkali solution.

4) Next, a drying process is performed to regulate the water content remaining in the filament, and then the filament is wound to obtain the aramid fiber.

The drying process of the filament may be made of a process of winding the filament on a drying roll heated to a predetermined temperature, wherein the process is applied to the filament by varying the process conditions such as the temperature, number, rotation speed of the drying roll Losing tension adjusts the final moisture content of the filament.

Such a filament drying process is a combination of a multi-stage drying process in order to gradually lower the moisture content of the filament under different tension conditions, specifically described as follows.

According to the present invention, first, while applying a predetermined tension to the filament, performing the first drying process so that the moisture content of the filament is in the range of 25% to 35%, and then applying a predetermined tension to the filament of the filament The second drying process is performed so that the moisture content is in the range of 10% to 15%, and then the third drying process is performed such that the moisture content of the filament is 5% or more and less than 10% while applying a predetermined tension to the filament. .

The moisture content may be calculated by measuring the weight (W ₁ ) of the filament in the state containing water and the weight (W ₂ ) of the filament after drying the moisture, specifically defined by Equation 1 below.

Moisture Content (%) = (W ₁ -W ₂ ) / W ₁ × 100

W ₂ in Equation 1 refers to the weight of the filament after drying the moisture for 2 hours at 105 ℃.

The step of adjusting the moisture content of the filament may be performed by adjusting the temperature of the drying roll or by adjusting the time of contacting the filament to the drying roll, the process of adjusting the time of contacting the filament to the drying roll It can be carried out by adjusting the number of dry rolls in contact with the filament.

Therefore, the filament obtained through the spinning process is wound on the first drying roll for the first drying step to adjust its moisture content, wherein the moisture content is adjusted by appropriately adjusting the number of first drying rolls and the temperature of the first drying roll. You can adjust the range from% to 35%. In addition, the filament adjusted to a moisture content range of 25% to 35% through the first drying process is wound on the second drying roll for the second drying process, and the moisture content is adjusted by appropriately adjusting the number and temperature of the second drying rolls. You can adjust the range from% to 15%. In addition, by adjusting the number and temperature of the third drying roll, the filament adjusted to the moisture content range of 10% to 15% through the second drying process can be adjusted so that the moisture content is more than 5% and less than 10%.

On the other hand, in the first drying step is applied a tension of 0.1 ~ 0.5g / d to the filament, and in the second drying step is less than the tension during the first drying step, specifically 0.05 ~ 0.1g to the filament A tension in the range of / d is applied, and a tension in the range of 0.1 to 0.5 g / d is applied to the filament during the third drying process.

The step of adjusting the tension applied to the filament can be carried out by adjusting the rotational speed of the drying roll, and thus, the filament obtained through the spinning process is wound around the first drying roll rotating at a predetermined speed, so that the tension in the range The first drying process is performed while applying, and then the second drying process is performed while applying the tension in the above range to the second drying roll which rotates at a speed lower than the rotation speed of the first drying roll.

When the tension applied to the filament during the first drying process and the third drying process is less than 0.1 g / d, the molecular orientation is reduced to obtain a fiber of the desired strength, the filament when the tension when drying exceeds 0.5 g / d Process control may be difficult, such as cutting. When the tension applied to the filament during the second drying process is less than 0.05 g / d, the molecular orientation may be reduced to decrease the fiber strength, when the tension exceeds 0.1 g / d may not be able to obtain a predetermined flexible filament .

As described above, according to the present invention, the tension applied to the filament during the second drying process is alleviated, because the second drying roll that rotates at a relatively slower speed than the first drying process is used during the second drying process. When the filament is controlled to a moisture content in the range of 10% to 15% while a tension is applied to the filament controlled to a water content range of 25% to 35% by the first drying process, specifically, to a certain amount of moisture. Flexibility can be increased.

As described above, the present invention performs the drying process while adjusting the tension according to the moisture content range of the filament, thereby increasing the flexibility of the aramid fibers, thereby improving the fiber properties such as strong retention and storage elastic retention, Explained as follows.

First, the aramid fibers according to the present invention has a strong retention of 80% or more. Strong retention is defined by Equation 2 below.

Strong retention rate (%) = S ₂ / S ₁ × 100

In Equation 2, S ₁ is the strength value of the yarn after repeated tensile tests for 24 hours with a force corresponding to 10% of the yarn strength at 30 ℃ temperature, S ₂ corresponds to 10% of the yarn strength at 150 ℃ temperature The strength of the yarn after repeated tests for 24 hours by force.

Next, the aramid fibers according to the present invention has a storage modulus retention of 90% or more. The storage elastic retention is defined by the following equation.

% Storage elasticity = L ₂ / L ₁ × 100

In Equation 3, L ₁ is a storage modulus value of the yarn measured by repeatedly applying stress to the yarn at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the yarn strength at 30 ° C. L ₂ is a storage modulus value of the yarn measured by repeatedly applying stress to the yarn at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the yarn strength at a temperature of 150 ° C. The storage elastic modulus of the yarn may be measured by DMTA (Dynamic mechanical thermal analysis) method, and can be measured by the model name "EXPLEXOR" equipment of Gabo.

3. Manufacture of bulletproof fabrics

1) Weave the fabric using plain or basket baskets as warp and weft yarns of the obtained aramid fibers.

In the weaving process, the warp density and weft density are preferably adjusted within the range of 5 to 15 yarns / cm. If the warp density and weft density are less than 5 bands / cm, the desired bulletproof characteristics may not be obtained. If the warp density and weft density are more than 15 bands / cm, the weaving property may be deteriorated during weaving.

The fineness of the aramid fiber is preferably in the range of 300 to 1600 denier. If the aramid fiber has a fineness of less than 300 deniers, the strength of the fabric may be lowered and the desired bulletproof characteristics may not be obtained. If the aramid fiber has a fineness of more than 1600 deniers, .

2) After the weaving process of the fabric, a scouring treatment process and a water repellent treatment process may be performed on the fabric.

The refining process is a process for removing the tannin or foreign matter adhered to the aramid fibers constituting the fabric. If the water-repellent process is performed without performing the refining process, the water-repellent process is not smoothly performed. May be reduced.

The refining process may be performed using a surfactant such as NaOH or Na ₂ CO ₃ at 40 ° C to 100 ° C. After the surfactant treatment, a washing process and a drying process are successively performed.

The water-repellent treatment process is a process for treating the fabric so as not to absorb moisture. When the aramid fiber constituting the fabric generally absorbs moisture for a long period of time, the physical properties thereof deteriorate, And water repellency treatment is performed to prevent deterioration of the bulletproof property due to moisture absorption.

The water-repellent treatment process may include a step of completely removing foreign matter adhered to the surface of the fabric through a refining process, as described above, and then dipping the fabric into the water repellent composition and drying.

Bulletproof fabric according to the present invention prepared by the process as described above is improved bulletproof properties by absorbing the impact when the bullet collides with the fabric, specifically, when overlapping the bulletproof fabric 30 to 38 sheets Bulletproof performance (V0) is superior to 436m / s based on NIJ level IIIA.

The above-described fabric for a bulletproof garment according to the present invention can be applied to a bulletproof product, for example, a bulletproof garment, a bulletproof helmet, and a bulletproof plate. The bulletproof helmet, the bulletproof helmet, and the bulletproof board may be manufactured by a known method, and the bulletproof helmet and the bulletproof plate may not be subjected to the water repellent treatment.

4. Example  And Comparative Example

1) Example 1

CaCl ₂ And N-methyl-2-pyrrolidone (NMP) were mixed to prepare a polymerization solvent. Thereafter, para-phenylenediamine was dissolved in the polymerization solvent to prepare a mixed solution. Thereafter, while the above mixed solution was being stirred, terephthaloyl dichloride was added to the mixed solution in the same molar amount as the para-phenylenediamine in two portions to produce a poly (paraphenylene terephthalamide) polymer. Thereafter, water and NaOH are added to the polymerization solution containing the polymer to neutralize the acid, the polymer is pulverized, and the polymerization solvent contained in the aromatic polyamide polymer is extracted using water, followed by dehydration and drying Finally, an aromatic polyamide polymer was obtained.

After dissolving the obtained aromatic polyamide polymer in 99% concentrated sulfuric acid, the spinning dope was spun through a spinneret, passed through an air layer of 7 mm, and the solidification tank and the solidification tank bottom containing the sulfuric acid solution. The filaments were made by solidifying while passing through the tube. During the passage of the solidification tube, an aqueous solution of sulfuric acid was sprayed onto the filament through an injection device. Thereafter, the filament was washed with water to remove the remaining sulfuric acid.

Thereafter, the filament is wound on a first drying roll to perform a first drying step, and then, the second drying roll is wound on a second drying roll to perform a second drying step, and then, the third drying roll is wound on a third drying roll to perform a third drying step. It was. At this time, the tension applied to the filament during the first drying process was adjusted to 0.1g / d, the moisture content of the filament after the first drying process was adjusted to 25%. In addition, the tension applied to the filament during the second drying process was adjusted to 0.05g / d, the moisture content of the filament was adjusted to 13% after the second drying process. In addition, the tension applied to the filament during the third drying process was adjusted to 0.1g / d, the moisture content of the filament was adjusted to 9% after the third drying process.

Thereafter, the dried filament was wound up to obtain aramid fibers of 1000 denier.

Thereafter, the warp and weft yarns were warp and wefted at a warp density and a weft density of 10 yarns / cm, respectively, to produce a fabric for armor protection.

2) Example 2

In Example 1 described above, the tension and moisture content of the first drying process is adjusted to 0.2g / d and 27%, respectively, and the tension and moisture content of the second drying process to 0.07 g / d and 15%, respectively, Bulletproof fabrics were prepared in the same manner as in Example 1, except that the tension and moisture content of the three drying processes were adjusted to 0.2 g / d and 7%, respectively.

3) Comparative Example 1

In Example 1 described above, the bulletproof fabric was prepared in the same manner as in Example 1, except that the tension and moisture content during the first to third drying processes were adjusted as shown in Table 1 below.

The specific drying process conditions of the above-described Examples and Comparative Examples are summarized in Table 1 below.

division
First drying process Second drying process Third drying process Moisture content (%) Tension (g / d) Moisture content (%) Tension (g / d) Moisture content (%) Tension (g / d) Example 1 25 0.1 13 0.05 9 0.1 Example 2 27 0.2 15 0.07 7 0.2 Comparative Example 1 10 0.5 8 0.5 7 0.5

5. Experimental Example

1) Measurement of physical properties of aramid fiber

Samples were prepared by cutting the aramid fibers prepared according to Example 1, Example 2, and Comparative Example 1 to 25 cm. Thereafter, the strength retention and storage elastic retention for each sample were measured according to the following equations (2) and (3). The results are shown in Table 2 below.

&Quot; (2) "

Strong retention rate (%) = S ₂ / S ₁ × 100

In Equation 2, S ₁ is the strength value of the yarn after repeated tensile tests for 24 hours with a force corresponding to 10% of the yarn strength at 30 ℃ temperature, S ₂ corresponds to 10% of the yarn strength at 150 ℃ temperature The strength of the yarn after repeated tests for 24 hours by force.

&Quot; (3) "

% Storage elasticity = L ₂ / L ₁ × 100

In Equation 3, L ₁ is a storage modulus value of the yarn measured by repeatedly applying stress to the yarn at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the yarn strength at 30 ° C. L ₂ is the storage modulus of the yarn measured by repeatedly applying stress to the yarn at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the yarn strength at a temperature of 150 ° C. Was measured using a Gabo model name "EXPLEXOR" equipment.

division Strong retention rate (%) Storage elastic retention (%) Example 1 85 92 Example 2 89 95 Comparative Example 1 75 82

2) Bulletproof performance test of fabric

After cutting the bulletproof fabric prepared according to Example 1, Example 2, and Comparative Example 1 into 40cm x 40cm to prepare 32 samples by overlapping the plywood, each prepared sample according to the National Institute of Justice (NIJ) standard Bulletproof test was performed. The bullet used in the bulletproof test is .44 mag. The results are shown in Table 3 below. In the following table, V0 is the maximum speed at which the bullet can not pass through the target, and according to the standard, V0 should be more than 436m / s.

division Bulletproof performance V0 (m / s) Example 1 440 Example 2 445 Comparative Example 1 420

Claims (9)

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 then spinning to produce a filament; And It comprises a step of drying the filament, The process of drying the filament comprises a first drying step of adjusting the moisture content of the filament to be in the range of 25% to 35%, and a second drying step of adjusting the moisture content of the filament to be in the range of 10% to 15%. under, The tension applied to the filament in the second drying process is less than the tension applied to the filament in the first drying process, the method of producing aramid fibers. The method according to claim 1, The tension applied to the filament during the first drying process is in the range of 0.1 ~ 0.5g / d, the tension applied to the filament during the second drying process is characterized in that the range of 0.05 ~ 0.1g / d range. The method according to claim 1, After the second drying step, a method of producing aramid fibers, characterized in that for performing a third drying step to control the filament moisture content is 5% or more and less than 10%. The method of claim 3, The tension applied to the filament during the third drying step is a method for producing aramid fibers, characterized in that 0.1 to 0.5g / d range. The method according to claim 1, The step of drying the filament is made of a process of winding the filament in a drying roll heated to a predetermined temperature, At this time, by adjusting the number and temperature of the drying roll to adjust the moisture content of the filament, and by adjusting the rotational speed of the drying roll to adjust the tension applied to the filament. An aramid fiber characterized in that an amide bond is bonded between the aromatic rings, the strong retention rate defined by the following formula 1 is 80% or more, and the storage elastic retention rate defined by the following formula 2 is 90% or more: Equation 1: Strong retention rate (%) = S ₂ / S ₁ × 100 (S ₁ is the strength value of the aramid fiber after repeated tensile test for 24 hours at a force corresponding to 10% of the strength of the aramid fiber at a temperature of 30 ℃, S ₂ is the aramid fiber at 150 ℃ temperature Strength of the aramid fibers after repeated tensile tests for 24 hours with a force corresponding to 10% of the strength of Equation 2: Storage Elasticity (%) = L ₂ / L ₁ × 100 [Wherein L ₁ is repeatedly applied to the aramid fibers at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the strength of the aramid fibers at a temperature of 30 ° C. The storage modulus of the aramid fibers measured by, wherein L ₂ is repeatedly stressed to the aramid fibers at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the strength of the aramid fibers at a temperature of 150 ℃ Storage elastic modulus of the aramid fibers measured by the DMTA method after the addition. A process for producing the aramid fiber according to any one of claims 1 to 5; And And a step of weaving the aramid fiber with warp and weft. Bulletproof and weft yarn is made of aramid fibers, the aramid fibers bulletproof characterized in that the strong retention rate defined by the following formula 1 is 80% or more, the storage elastic retention rate defined by the following formula 2 is 90% or more Dragon Fabric: Equation 1: Strong retention rate (%) = S ₂ / S ₁ × 100 (S ₁ is the strength value of the aramid fiber after repeated tensile test for 24 hours at a force corresponding to 10% of the strength of the aramid fiber at a temperature of 30 ℃, S ₂ is the aramid fiber at 150 ℃ temperature Strength of the aramid fibers after repeated tensile tests for 24 hours with a force corresponding to 10% of the strength of Equation 2: Storage Elasticity (%) = L ₂ / L ₁ × 100 [Wherein L ₁ is repeatedly applied to the aramid fibers at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the strength of the aramid fibers at a temperature of 30 ° C. The storage modulus of the aramid fibers measured by, wherein L ₂ is repeatedly stressed to the aramid fibers at a frequency of 50 Hz for 50 hours with a force corresponding to 5% of the strength of the aramid fibers at a temperature of 150 ℃ Storage elastic modulus of the aramid fibers measured by the DMTA method after the addition. 9. The method of claim 8, Characterized in that the bulletproof fabric has a bulletproof performance (V0) of 436 m / s or higher on the basis of NIJ level IIIA when 30 to 38 layers are overlapped.