KR20110034942A - Aramid fiber, method of manufacturing aramid fiber, bulletproof fabric, and method of manufacturing bulletproof fabric - Google Patents

Abstract

PURPOSE: A method for manufacturing aramide fiber is provided to improve bulletproof property by optimizing a drying process. CONSTITUTION: A method for manufacturing aramide fiber comprises: a step of polymerizing aromatic diamine and aromatic diacid halide to prepare an aromatic polyamide polymers; a step of dissolving the aromatic polyamide polymers in a solvent to prepare a spinning dope and spinning to obtain a filament; and a step of drying the filament using a first drying roll and nth drying roll.

Description

Aramid fiber and its manufacturing method, and a bulletproof fabric using the same and a method for manufacturing the same {Aramid Fiber, method of manufacturing Aramid Fiber, bulletproof fabric, and method of manufacturing bulletproof fabric}

The present invention relates to a bulletproof fabric, and more particularly to a bulletproof fabric using aramid fibers.

Bulletproof fabrics are fabrics used in a variety of bulletproof products, such as body armor, bulletproof helmets, bulletproof boards. Bulletproof products are products to protect the human body from the bullet or shell fracture. Bulletproof performance of bulletproof products depends on the bulletproof performance of the fabric for bulletproof, and the bulletproof performance of the bulletproof fabric depends on the characteristics of the yarn and the fabric. It is determined by organizational structure and the like.

Yarns used in bulletproof fabrics should generally have high strength properties, and aramid fibers are known as yarns having such properties.

Aramid fibers are named as aromatic polyamide fibers, and a process for producing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic dieside chloride in a polymerization solvent, and a process for producing a spinning dope by dissolving the aromatic polyamide polymer in a solvent. , And after the spinning dope is spun through a spinneret, the spinning is solidified to produce a filament.

When the bulletproof fabric is manufactured using such aramid fibers, the bulletproof fabric obtained by the high strength characteristics of the aramid fibers also has high strength characteristics, but has not yet obtained the desired bulletproof characteristics.

In more detail, when the bullet collides with the bulletproof fabric, the yarn constituting the fabric is not easily destroyed by the impact, and the shock to the human body is minimized only by absorbing the impact easily.

Aramid fibers are not easily destroyed by the impact of bullets because they have excellent orientation and high strength properties of crystal parts, but due to the lack of flexibility of the fibers, the effect of absorbing the impact of the bullets is somewhat reduced. The anti-ballistic fabric used has not yet obtained the desired anti-ballistic properties.

It is an object of the present invention to provide an aramid fiber and a method for manufacturing the same, and a fabric for bulletproof using the same, and a method for producing the same, by improving the flexibility of the aramid fiber to more easily absorb the impact of the bullet and improve the bulletproof property.

The inventors of the present invention, while studying to improve the flexibility of the aramid fiber, it was confirmed that the flexibility of the aramid fiber can be improved if the drying process of the filament after the spinning process is optimized.

Specific solutions of the present invention as described above are 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 prepare a filament; And drying the filaments using the first to n-th dry rolls, wherein, in the first to n-th dry rolls, the tension by the preceding dry rolls and the subsequent dry rolls. It provides a method for producing aramid fibers characterized in that the tension by the drying rolls is adjusted so that the tension ratio between the tension by less than one is at least one time.

Here, the tension ratio between the tension by the first dry roll and the tension by the n-th dry roll can be adjusted to be 0.9 ~ 1.2.

The product of the tension ratios between the tension by the preceding dry roll and the tension by the subsequent dry roll may be in the range of 0.8 to 1.1.

The tension by each of the first to n-th dry roll may be in the range of 0.05 g / d ~ 3 g / d.

The present invention provides an aramid fiber characterized in that the amide bond is bonded between the aromatic rings, the work loss ratio is 20% or less.

Here, the aramid fibers may be less than 2% elongation strain.

The present invention is a process for producing the aramid fibers described above; 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 also provides a ballistic weave fabric, characterized in that the warp and weft yarn is made of aramid fibers, the aramid fibers have a work loss of 20% or less, elongation strain 2% or less.

When the bulletproof fabric is overlapped with 30 to 38 sheets, the bulletproof performance (V0) may be 436 m / s or more based on NIJ level IIIA.

According to the present invention as described above has the following effects.

The present invention can obtain aramid fibers with improved flexibility by optimizing the drying process of the filament after the spinning process in the aramid fiber manufacturing process, by producing a bulletproof fabric using such aramid fibers, It has the effect of improving bulletproof characteristics.

Hereinafter, a preferred embodiment 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 the 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'-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.

2) Next, an aromatic diamine is dissolved in the prepared polymerization solvent to prepare a mixed solution.

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

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

In the polymerization of the aromatic diamine and the aromatic dieside halide, the reaction proceeds at a high rate with exotherm. In this way, when the polymerization rate is high, there is a problem in that the degree of polymerization differs between the finally obtained polymers. 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 a shorter molecular chain than the polymer from which the reaction began. The higher the polymerization rate, the larger the difference. As such, when the degree of polymerization difference between the polymers finally obtained increases, physical property variations also increase, making it difficult to achieve desired characteristics.

Therefore, the prepolymerization step is to minimize the degree of polymerization between the polymers finally obtained by forming a polymer having a molecular chain of a predetermined length in advance and then performing a polymerization step.

Specific examples of the aromatic dieside halides include terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalenedicarboxylic acid dichloride or 1,5-naphthalenedicarboxylic acid dichloride, It is not necessarily limited thereto.

4) Next, after the completion of the prepolymerization step, the remaining amount of the aromatic dieside halide is added to the mixed solution while stirring at 0 ~ 30 ℃ state and polymerized.

In the preparation of the aromatic polyamide, since the aromatic dieside halide reacts with the aromatic diamine in a 1: 1 molar ratio, the aromatic diamine and the aromatic dieside halide can be added in 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), and 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. Since such acid causes problems such as corrosion of the polymerization apparatus, an acid generated during the polymerization reaction by adding an inorganic alkali compound or an organic alkali compound during or after the polymerization reaction. To neutralize.

At this time, since the aromatic polyamide obtained through the polymerization reaction is present in the form of bread crumb, the fluidity of the aromatic polyamide solution is not good. Therefore, in order to improve the fluidity, it is preferable to proceed with the subsequent process while adding water to the aromatic polyamide solution to make a slurry, and for this purpose, neutralizing by adding water together with an alkali compound to the aromatic polyamide solution during the neutralization process. The process can proceed.

The inorganic 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, alkaline earth metal It is selected from the group which consists of a hydroxide or an oxide of an alkaline earth metal.

6) Next, the neutralization process is completed to grind the aromatic polyamide polymer 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.

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

Since the polymerization solvent used for the polymerization process is contained in the aromatic polyamide polymer obtained by the polymerization, 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 dehydrated, and then dried to complete the production of the aromatic polyamide polymer.

2. Aramid  Manufacture of fibers

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

The solvent may be a concentrated sulfuric acid solvent having a concentration of 97 to 100%, and chloro sulfuric acid, fluoro sulfuric acid, or the like may be used instead of concentrated sulfuric acid.

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 the bottom of the spinneret and a coagulation solution is stored therein, and a coagulation tube is formed at the bottom of the coagulation bath. Accordingly, the radiant passing through the capillary of the spinneret is solidified while sequentially descending through the air gap and the coagulating liquid to form a filament, and the filament is discharged while passing through the coagulation tube below 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 injection device has a plurality of jet openings and injects the coagulating liquid toward the filaments from the plurality of injection openings.

The coagulating solution may be added 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, sulfuric acid remaining in the obtained filament is removed.

Since sulfuric acid solution is used in the preparation of the spinning dope, sulfuric acid may remain in the filament produced by the spinning process. 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.

4) Next, in order to control the moisture content remaining in the filament, the drying step is performed and then wound to obtain aramid fibers.

The drying process of the filament is carried out using a multi-stage drying roll, that is, the first to n-th dry roll (where n is 2 or more, preferably 3 or more), wherein the drying roll By adjusting the rotational speed, the tension applied to the filament by each drying roll is controlled.

Specifically, according to the present invention, when performing the drying process using the first to n-th dry roll, the tension ratio between the tension by the preceding drying roll and the tension by the subsequent drying roll is less than 1 The tension by the drying rolls is adjusted to be at least one time. For example, when the drying roll is composed of a total of three drying rolls from the first to the third drying roll, the tension of the second drying roll / the tension of the first drying roll is a, the tension of the third drying roll / When the tension of the second dry roll is b, at least one of a and b is less than one.

Thus, in performing the drying process in the plurality of drying rolls, the aramid fibers finally obtained by providing a relaxation section in which a tension ratio between the tension by the preceding drying roll and the tension by the subsequent drying roll is less than 1 in some sections. The flexibility of can be increased.

Further, according to the present invention, the tension ratio between the tension by the first dry roll (first dry roll) and the tension by the last dry roll (n-th dry roll), that is, the tension / first of the n-th dry roll It is preferable to adjust the tension of the drying roll to 0.9 to 1.2. When the tension of the nth dry roll / the tension of the first dry roll is less than 0.9, the molecular orientation of the filament during drying is reduced to obtain a fiber of the desired strength, when the tension ratio is greater than 1.2, the relaxation period of less than 1 It can be difficult to give.

Further, the product of the tension ratios between the tension by the preceding drying roll and the tension by the subsequent drying roll is preferably in the range of 0.8 to 1.1. For example, when the drying roll is composed of a total of three drying rolls from the first to the third drying roll, the tension of the second drying roll / the tension of the first drying roll is a, the tension / of the third drying roll When the tension of the second dry roll is b, the value of a × b is preferably in the range of 0.8 to 1.1. If the product of the tension ratios is less than 0.8, the fiber of the desired strength cannot be obtained, and if the product exceeds 1.1, it may not be possible to finally obtain a flexible fiber.

The tension applied to the filament by each of the first to n-th dry rolls is preferably in the range of 0.05 g / d to 3 g / d. If the tension is less than 0.05 gpd molecular orientation is reduced to obtain a fiber of the desired strength, if the tension exceeds 3.0 gpd during drying, there is a fear that the filament may be cut may cause manufacturing difficulties.

The aramid fibers obtained through such a drying process is to improve the flexibility, thereby improving the fiber properties such as work loss rate and elongation strain, which will be described in detail as follows.

First, the aramid fibers according to the present invention has a work loss ratio of 20% or less. The daily loss rate is defined by Equation 1 below.

Work loss rate (%) = Work loss / Loading energy × 100

In Equation 1, the work loss is to remove the unloading energy from the loading energy, and the weighted energy is repeated ten times with a load corresponding to 20% cutting strength of the aramid yarn. It is the energy value after an experiment, and the weight-in energy means the energy value after removing a load to an aramid yarn.

Next, the aramid fibers according to the present invention is less than 20% elongation strain. Elongation strain is defined by the following equation (2).

Elongation at break (%) = (L ₁ -L ₀ ) / L ₀ × 100

In Equation 2, L ₁ is the length of the yarn after 10 repeated tensile tests under a load corresponding to 20% of the cutting strength of the yarn, L ₀ is the length of the aramid yarn before the repeated test under the load.

3. Manufacture of Bulletproof Fabrics

1) The obtained aramid fibers are inclined and wefted, and the fabric is woven with plain or basket weaving.

Inclined density and weft density during the weaving process is preferably adjusted within the range of 5 ~ 15 bone / cm. When the warp density and the weft density is less than 5 bone / cm, the desired antiballistic property may not be obtained. When the warp density and the weft density exceeds 15 bone / cm, weaving may be degraded during the weaving process of the fabric.

The fineness of the aramid fibers is preferably in the range of 300 to 1600 denier. When the fineness of the aramid fibers is less than 300 denier, the strength of the fabric may be reduced to obtain desired antiballistic properties, and when the fineness of the aramid fibers exceeds 1600 denier, weaving may be reduced during the weaving process of the fabric. .

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

The refining process is to remove the oil or foreign matter adhering to the aramid fibers constituting the fabric, if the water repellent treatment process is performed without performing such a refining process, the water repellent treatment process is not made smoothly The flexibility of may be lowered.

The refining process may be carried out using a surfactant such as NaOH or Na ₂ CO ₃ at 40 ℃-100 ℃, after the surfactant treatment is followed by a washing step and a drying step.

The water-repellent treatment process is a process to prevent the fabric from absorbing moisture, the aramid fibers constituting the fabric is generally a problem that the long-term absorption of water is deteriorated in physical properties and eventually the ballistic characteristics of the fabric is gradually degraded to the fabric Water repellent treatment to prevent the deterioration of ballistic resistance due to water absorption.

As described above, the water repellent treatment process may be performed by completely removing the foreign matter adhered to the surface of the fabric through a refining process, and then immersing the fabric in 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 anti-ballistic fabric according to the present invention as described above can be applied to bulletproof products, examples thereof include a body armor, a bulletproof helmet, and a bulletproof plate. The body armor, bulletproof helmet, and bulletproof plate may be manufactured by a known method, wherein the bulletproof helmet and bulletproof plate may not perform the above-described water repellent treatment process.

4. Example  And Comparative example

1) Example 1

CaCl ₂ And N-methyl-2-pyrrolidone (NMP) were mixed to prepare a polymerization solvent, and then para-phenylenediamine was dissolved in the polymerization solvent to prepare a mixed solution. Thereafter, while stirring the mixed solution, terephthaloyl dichloride of the same mole as the para-phenylenediamine was added to the mixed solution in two portions to produce a poly (paraphenylene terephthalamide) polymer. Thereafter, water and NaOH are added to the polymerization solution including 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.

Thereafter, the obtained aromatic polyamide polymer was dissolved in 99% concentrated sulfuric acid, and then the spinning dope was spun through a spinneret, passed through an air layer of 7 mm, and the coagulation bath containing the sulfuric acid aqueous solution and the coagulation of the bottom of the coagulation bath. Filaments were made by solidifying while passing through a tube. While passing the coagulation tube, an aqueous sulfuric acid solution was injected into the filament through an injection device. Thereafter, the filament was washed with water to remove residual sulfuric acid.

Then, the drying process for the filament was performed using a total of five drying rolls of the first to fifth drying rolls. At this time, the tension in the first drying roll is 1.0g / d, the tension in the second drying roll is 1.0g / d, the tension in the third drying roll is 0.9g / d, in the fourth dry roll The tension of 0.8g / d, the tension in the fifth drying roll was adjusted to 0.9g / d. Therefore, the tension of the fifth drying roll (last drying roll) / tension of the first drying roll (first drying roll) is 0.9, the tension of the second drying roll / tension of the first drying roll is 1.0, The tension of the third dry roll / tension of the second dry roll is 0.9, the tension of the fourth dry roll / tension of the third dry roll is about 0.9, and the tension of the fifth dry roll / tension of the fourth dry roll. Is about 1.1.

Thereafter, the filament in which the drying step was completed was wound up to obtain 1000 denier aramid fibers.

Thereafter, the aramid fibers were used as warp and weft yarns, and the warp and weft densities were 10 weaves / cm, respectively.

2) Example 2

In Example 1 described above, bulletproof fabrics were manufactured in the same manner as in Example 1, except that the tension of the first to fifth dry rolls was adjusted as in Table 1 below.

3) Comparative Example

In Example 1 described above, bulletproof fabrics were manufactured in the same manner as in Example 1, except that the tension of the first to fifth dry rolls was adjusted as in Table 1 below.

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

Roll tension (g / d) Tension ratio
(Final roll /
First roll) Tension ratio
(Trailing roll / leading roll) Product of tension ratios
First
2nd
The third
4th
5th
5 /
First 2 /
First 3 /
2nd 4 /
The third 5 /
4th
Example 1 1.0 1.0 0.9 0.8 0.9 0.9 1.0 0.9 About 0.9 About 1.1 About 0.9
Example 2 1.0 1.0 0.9 0.9 1.1 1.1 1.0 0.9 1.0 About 1.2 About 1.1
Comparative example 1.0 1.2 1.4 1.6 1.8 1.9 1.2 About 1.2 About 1.1 About 1.1 About 1.7

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 to 25 cm. Thereafter, the work loss ratio and the elongation strain of each sample were measured according to the following equations (1) and (2). The results are shown in Table 2 below.

[Equation 1]

Work loss rate (%) = Work loss / Loading energy × 100

In Equation 1, the work loss is to remove the unloading energy from the loading energy, and the weighting energy is 10 times of tensile repetition experiments with a load corresponding to 20% cutting strength of the aramid yarn. It is a later energy value, and an energy in weight means the energy value after removing a load to an aramid yarn.

[Equation 2]

Elongation at break (%) = (L ₁ -L ₀ ) / L ₀ × 100

In Equation 2, L ₁ is the length of the yarn after 10 repeated tensile tests under a load corresponding to 20% of the cutting strength of the yarn, L ₀ is the length of the aramid yarn before the repeated test under the load.

division Daily loss rate (%) Elongation at Strain (%) Example 1 17 1.7 Example 2 15 1.2 Comparative Example 1 25 2.9

2) Bulletproof performance test of fabric

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

division Bulletproof performance V0 (m / s) Example 1 440 Example 2 443 Comparative Example 1 421

Claims (9)

Polymerizing the aromatic diamine and the aromatic dieside halide to prepare an aromatic polyamide polymer; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope and then spinning to prepare a filament; And It comprises a step of drying the filament using the first to n-th dry roll, At this time, in the first to n-th dry roll, the tension by the drying roll is adjusted so that the tension ratio between the tension by the preceding drying roll and the tension by the subsequent drying roll is less than one or more times. Method for producing aramid fiber, characterized in that. The method of claim 1, Method for producing aramid fibers, characterized in that the tension ratio between the tension by the first drying roll and the tension by the n-th dry roll is adjusted to 0.9 ~ 1.2. The method of claim 1, A product of the aramid fibers, characterized in that the product of the tension ratio between the tension by the preceding drying roll and the tension by the subsequent drying roll is in the range of 0.8 ~ 1.1. The method of claim 1, Tension by each of the first to n-th dry roll is a method for producing aramid fibers, characterized in that in the range of 0.05 g / d ~ 3 g / d. An amide bond is bonded between aromatic rings, and the aramid fiber characterized by a work loss rate of 20% or less. The method of claim 5, The aramid fiber is an aramid fiber, characterized in that the elongation strain is 2% or less. Manufacturing the aramid fibers according to any one of claims 1 to 4; And Method of producing a bulletproof fabric comprising the step of weaving the aramid fibers as warp and weft. The warp and weft yarn is made of aramid fiber, the aramid fiber has a work loss ratio of 20% or less, elongation strain is characterized in that less than 2%. The method of claim 8, The bulletproof fabric is bulletproof fabric, characterized in that the bulletproof performance (V0) is more than 436m / s on the basis of NIJ level IIIA when 30 ~ 38 sheets overlap.