KR20120073438A - Method for manufacturing aramid fiber - Google Patents

Abstract

PURPOSE: A method for fabricating aramid fibers is provided to ensure high tensile strength and to manufacture a bulletproof jacket, bulletproofing helmet, cable, and reinforcing material. CONSTITUTION: A method for fabricating aramid fibers comprises: a step of dissolving aromatic polyamide polymers in a solvent to prepare spinning dope; a step of spinning the spinning dope through a spinneret(10); and a step of solidifying the spinning dope through an air gap(20), a solidifying tank(30), and a solidifying tube(40) in order to prepare a filament(1). The solidifying tube has a nozzle(50) which is connected to the inside of the solidifying tube to spray a solidifying solution to the filament.

Description

Method for manufacturing Aramid fiber {Method for manufacturing Aramid fiber}

The present invention relates to a method for producing aramid fibers, and more particularly to a method for producing aramid fibers that can be produced at high speed.

Generally, wholly aromatic polyamides, collectively referred to as aramids, include para-aramids and meta-aramids having a structure in which the benzene rings are connected linearly through an amide group (CONH). Para-based aramis have excellent properties such as high strength, high elasticity, and low shrinkage.The 5mm thick thin thread manufactured therefrom has a strong strength enough to lift 2 tons of cars and is used for bulletproof applications. It is used in a variety of applications in the high-tech industry in the aerospace field.

Such aramid fibers are prepared by polymerizing an aromatic diamine and an aromatic dieside chloride in NMP, which is a polymerization solvent, to prepare an aromatic polyamide polymer, dissolving the aromatic polyamide polymer in a concentrated sulfuric acid solvent to prepare a spinning dope, and the spinning dope. After spinning through a spinneret, the spinning dope is solidified in a coagulation solution, and is manufactured through a process of manufacturing a filament.

Since the aramid fibers are produced by solidifying the spinning dope in a coagulating solution after spinning the spinning dope, when flowing at high speed, the flow flow of the filament becomes unstable, resulting in a poor manufacturing processability and a deterioration in physical properties.

The present invention is to solve the above problems, the injection angle formed by the coagulating liquid injection direction of the injection port and the traveling direction of the filament achieves an optimal range, the ejection speed and spinning speed of the coagulation liquid at the bottom exit of the coagulation tube The purpose of the present invention is to provide a method for producing aramid fibers having excellent tensile strength even though the process flows smoothly as the flow of the filament is stabilized even though the spinning dope is spun at high speed.

The present invention for achieving the above object is a process for preparing a spinning dope by dissolving the aromatic polyamide polymer in a solvent; Spinning the spinning dope through a spinneret; And producing a filament by solidifying the radiated spinning dope through an air gap, a coagulation bath, and a coagulation tube communicating with the bottom of the coagulation tank, wherein the coagulation tube is for injecting a coagulant solution into the filament. An injection hole communicating with the inside of the coagulation tube, the injection angle formed by the injection direction of the coagulation solution of the injection hole and the advancing direction of the filament is 5 to 15 °, and the coagulation solution is ejected from the bottom exit of the coagulation tube. The speed provides a method for producing aramid fibers, characterized in that 25 to 40% of the spinning speed.

The present invention has the following effects.

First, the present invention is excellent in fairness because the flow flow of the filament is stable even if the spinning dope is spun at a high speed as the coagulating liquid is injected into the filament through the injection hole forming the optimum injection angle with the spinning tube.

Second, the present invention is excellent in fairness because the flow rate of the filament is lowered and the flowability of the filament is excellent as the ejection rate of the coagulating liquid at the bottom exit of the coagulation tube has an optimal range compared to the spinning speed.

Third, the aramid fibers according to the present invention can have excellent tensile strength because the flow of the filament is stable even when spinning at high speed.

Such aramid fibers having excellent tensile strength can be utilized in various fields such as body armor, bulletproof helmets, cables, and reinforcing materials.

1 is a schematic diagram of a radiating device according to an embodiment of the present invention.

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

As used herein, "spinning speed" refers to the speed of the filament passing through the bottom outlet of the coagulation tube.

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

First, the aromatic polyamide polymer is dissolved in a solvent to prepare a spinning dope.

As the solvent, if a concentrated sulfuric acid solvent having a concentration of 97 to 100% can be used, chloro sulfuric acid, fluoro sulfuric acid and the like can also be used instead of concentrated sulfuric acid.

The polymer concentration in the spin dope may be 10 to 25% by weight. It is preferable that the polyamide polymer concentration in the spinning dope exceeds the critical concentration, but if the concentration is too large, it may be preferable to have the above range because the viscosity of the spinning dope is too low.

The aromatic polyamide polymer may be prepared by the following method.

First, an aromatic diamine is dissolved in a polymerization solvent to prepare a mixed solution. The polymerization solvent may be prepared by adding an inorganic salt to the organic solvent. Subsequently, a small amount of aromatic dieside halide is added to the mixed solution while the mixed solution is stirred, followed by prepolymerization, and then the remaining amount of aromatic dieside halide is added to the mixed solution to polymerize. This prepolymerization process minimizes the difference in degree of polymerization between the final polymers by first forming a polymer having a molecular chain of a predetermined length and then performing a polymerization process.

Next, as can be seen in Figure 1, after spinning the spinning dope through a predetermined spinneret 10, the filament (1) by solidifying the air gap 20, the coagulation bath 30 and the coagulation tube 40 in order To form. The air gap 20 is composed of an air layer or an inert gas layer.

The coagulation bath 30 is located below the air gap 20, and a coagulation liquid 31 is stored therein, and a coagulation tube 40 is formed below the coagulation bath 30. The coagulation tube 40 is in communication with the bottom of the coagulation tank 30 so that the filament (1) can continuously pass through the coagulation tank 30 and the coagulation tube (40).

Accordingly, the spinning dope radiated through the spinneret 10 is solidified while sequentially passing through the air gap 20 and the coagulating liquid 31 to be discharged through the coagulation tube 40 while forming the filament 1. . In addition to the filament 1, the coagulation solution 31 is also discharged through the coagulation tube 40, so that the coagulation solution 31 must be continuously supplied to the coagulation bath 30 by the discharge amount.

The coagulation tube 40 is formed with a spray port 50 in communication with the inside. The injection hole 50 further solidifies the filament 1 by injecting the coagulation liquid 31 into the filament 1 passing through the inside of the coagulation tube 40 and induces the flow of the filament 1.

A plurality of injection holes 50 may be formed around the coagulation tube 40, and the coagulation solution 31 may be disposed to be symmetrically injected with respect to the filament 1.

Typically, aramid fibers are made by spinning the spinning dope at a spinning speed of less than 1000 minutes / meter. As described above, since the aramid fibers are manufactured through solution spinning, when the spinning speed is excessively high, the flow flow of the filament 1 becomes unstable, and thus the filaments 1 may be in contact with each other, resulting in uneven cross-sectional shape. One property may be obtained and, if severe, the filament 1 may be cut and a problem of stopping the manufacturing process may occur.

In addition, when the spinning speed is increased, the shear stress during spinning is greatly increased and the tensile strength may be lowered because the entire filament 1 is not uniformly solidified.

Therefore, in order to stabilize the flow fluidity of the filament 1 formed after spinning in high-speed spinning, the shape of the coagulation bath 30 and the coagulation tube 40, the temperature and components of the coagulation liquid 31, and the like are affected.

In particular, in order to stabilize the flow fluidity of the filament 1 when spinning at a high speed, the injection angle θ formed between the advancing direction of the filament 1 and the jetting direction of the coagulating liquid 31 of the jetting port 50 has a large influence. Was confirmed through the study.

On the other hand, the aramid fibers of the present invention are produced at a spinning speed of 1,000 to 2,000 minutes / meter. Typically, aramid fibers are produced at low spinning speeds of less than 1,000 minutes / meter, resulting in poor productivity. However, the aramid fibers of the present invention can be produced at a spinning speed of 1,000 to 2,000 minutes / meter can greatly improve productivity.

However, as described above, as the spinning speed increases, the flowability of the filament 1 may become unstable, and thus, the filaments 1 may be cut by contacting the filaments 1 and thus the manufacturing process may be interrupted. In addition, as the spinning speed increases, physical properties such as tensile strength may deteriorate because the filaments 1 coagulate unevenly.

Accordingly, the injection angle θ formed between the advancing direction of the filament 1 and the jetting direction of the coagulating liquid 31 of the jetting port 50 forms 5 to 15 °.

That is, according to the present invention, since the coagulating liquid 31 in the injection hole 50 communicating with the coagulation tube 40 is injected into the filament 1 at an optimum angle, the fluid flow of the filament 1 is stabilized. The aramid fibers having excellent tensile strength can be produced as the filament 1 is uniformly solidified without deteriorating the manufacturing processability.

If the injection angle θ is less than 5 °, the pumping capacity of the coagulating solution 31 stored in the coagulation bath 30 may be reduced. That is, when the coagulation solution 31 is radiated from the injection hole 50, a pressure difference occurs between the coagulation tank 30 and the coagulation tube 40, so that the coagulation solution 31 stored in the coagulation tank 30 becomes the coagulation tube 40. Is pumped to move quickly into, the pumping capacity for such coagulating liquid 31 may be degraded if the injection angle θ is too low. In addition, when the spraying angle θ is less than 5 °, the contact point between the filament 1 and the coagulating liquid 31 injected from the injection hole 50 is continuously lowered, thereby ensuring the oiliness of the coagulating liquid 31. In order to increase the length of the injection hole 50 and at the same time there is a problem that the diameter of the injection hole 50 must be large.

On the other hand, when the injection angle θ exceeds 15 °, as the flowability of the filament 1 becomes unstable, manufacturing processability may decrease. That is, when the injection angle θ exceeds 15 °, the contact point of the filament 1 and the coagulation liquid 31 injected from the injection hole 50 is continuously increased, so that the filament 1 and the coagulation liquid 31 are It may not be able to move smoothly to the lower part, and as a result, the fluidity flow of the filament 1 may become unstable, thereby decreasing manufacturing processability.

The ejection rate (Vq) of the coagulation liquid 31 ejected through the bottom outlet of the coagulation tube 40 is 25 to 40% compared to the spinning rate (V2).

When the spraying speed Vq of the coagulating liquid 31 is less than 25% of the spinning speed V2, the filament 1 receives a large resistance while vertically moving the filament 1 by the low speed coagulating liquid 31. The tensile strength of 1) may be lowered.

On the other hand, when the spraying speed (Vq) of the coagulating liquid 31 exceeds 40% of the spinning speed (V2) to the coagulating liquid 31 is ejected through the bottom outlet of the coagulation tube 40 is severely shaken Accordingly, if the shape of the filament 1 is unstable and severe, the filament 1 may be cut and the manufacturing process may be interrupted.

The injection hole 50 is formed in the circumference of the coagulation tube 40 may be injected into the coagulation tube (40) of the multi-stage coagulation liquid 31. In this way, when the coagulating liquid 31 is sprayed in multiple stages, the force applied to the filament 1 can be dispersed, so that the surface of the filament 1 becomes uniform, the orientation is improved, and the strength decreases, and the filament 1 The rapid escape of sulfuric acid from) can be prevented to improve the uniformity of the surface.

The coagulation solution 31 may be a sulfuric acid solution. The spinning dope spun from the spinneret 10 forms the filament 1 while the sulfuric acid inside thereof is extracted in the course of passing through the coagulating solution 31. At this time, if sulfuric acid is rapidly removed from the surface of the filament (1), such a problem may occur because the surface of the filament (1) is solidified before the sulfuric acid contained therein can escape, may cause the uniformity of the filament (1) to fall In order to solve this problem, sulfuric acid is added to form a coagulation solution 31.

Next, sulfuric acid remaining in the obtained filament 1 is removed.

Sulfuric acid may remain in the filament 1 produced by the spinning process. Thus, sulfuric acid remaining in the filament 1 may be removed through a washing process using water or a mixed solution of water and an alkaline solution.

Next, a drying process is performed to control the moisture content remaining in the filament (1). The drying process may control the moisture content of the filament (1) by adjusting the time the filament (1) is in contact with the heated drying roller and the temperature of the drying roller.

Next, the dried filament 1 is wound around the branch pipe driven by the winder to complete the aramid fiber.

Since the aramid fiber according to the present invention obtained through such a process is stably wound on the branch pipe without cutting the filament (1), the average winding time of the filament (1) may be 24 hours or more. Therefore, the aramid fiber according to the present invention is excellent in economy because the production per hour is high as it has a high average winding time.

In addition, the aramid fibers according to the present invention obtained through such a process may have a tensile strength of 20 g / d or more. Such aramid fibers having excellent tensile strength can be utilized in various fields such as body armor, bulletproof helmets, cables, and reinforcing materials.

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 should not be limited thereto.

Example  One

CaCl ₂ was added to N-methyl-2-pyrrolidone (NMP) 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 were added to the polymerization solution containing the polymer to neutralize the acid. Thereafter, after pulverizing the polymer, the polymerization solvent contained in the aromatic polyamide polymer was extracted using water, and finally, the aromatic polyamide polymer was obtained through a dehydration and drying process.

Thereafter, the obtained aromatic polyamide polymer was dissolved in 99% concentrated sulfuric acid to prepare a spinning dope. Thereafter, after spinning the spinning dope using the spinning device as shown in Figure 1, the air gap 20, the coagulation tank 30, the coagulation liquid 31 is contained and the solidification formed with the injection port 50 The filament 1 was prepared by coagulation while passing through the tube 40.

At this time, the injection angle θ formed between the injection direction of the coagulating liquid 31 of the injection hole 50 and the traveling direction of the filament 1 is 5 °, and the spinning speed V2 of the filament 1 is 1500. The ejection rate (Vq) of the coagulation liquid 31 at the bottom outlet of the coagulation tube (40) was 30% compared to the spinning speed (V2).

Thereafter, the filament 1 was washed with water to remove residual sulfuric acid, dried, and wound up to prepare 1,000 denier aramid fibers.

Example  2 to 3

In Example 1 described above, aramid fibers were prepared in the same manner as in Example 1 except that the injection angles θ were changed to 10 and 15 °, respectively.

Example  4 to 6

In Example 1 described above, except that the speeds V2 of the filaments 1 were all changed to 1900 minutes / meter and the injection angles θ were changed to 7, 12, and 15 °, respectively. Aramid fibers were prepared in the same manner as in 1.

Example  7 to 8

In Example 1 described above, except that the injection angle was changed to 10 °, and the jetting speed Vq of the coagulating liquid 31 was changed to 25% and 40% of the spinning speed V2, respectively. Prepared aramid fibers in the same manner as in Example 1.

Comparative example  1 to 3

In Example 1 described above, aramid fibers were prepared in the same manner as in Example 1 except that the injection angles θ were changed to 17, 27, and 37 °, respectively.

Comparative example  4 to 6

In Example 1 described above, except that the speeds V2 of the filaments 1 were all changed to 1900 minutes / meter and the injection angles θ were changed to 20, 30, and 40 °, respectively. Aramid fibers were prepared in the same manner as in 1.

Comparative example  7 to 8

In Example 1 described above, except that the injection angle was changed to 10 °, and the jetting speed Vq of the coagulating liquid 31 was changed to 20% and 45%, respectively, relative to the spinning speed V2. Prepared aramid fibers in the same manner as in Example 1.

To summarize the main process conditions according to the above Examples and Comparative Examples are shown in Table 1.

division Injection angle (°) V2 (minutes / meters) Vq (%) Example 1 5 1500 30 Example 2 10 1500 30 Example 3 15 1500 30 Example 4 7 1900 30 Example 5 12 1900 30 Example 6 15 1900 30 Example 7 10 1500 25 Example 8 10 1500 40 Comparative Example 1 17 1500 30 Comparative Example 2 27 1500 30 Comparative Example 3 37 1500 30 Comparative Example 4 20 1900 30 Comparative Example 5 30 1900 30 Comparative Example 6 40 1900 30 Comparative Example 7 5 1500 20 Comparative Example 8 5 1500 45

Tensile strength and winding time of the aramid fibers obtained by the above Examples and Comparative Examples was measured by the following method, the results are shown in Table 1.

Tensile Strength and Elongation of Aramid Fibers

Tensile strength and elongation of aramid fibers were measured by tensile strength until the 25 cm long sample was broken in an Instron Engineering Corp. (Canton, Mass) according to ASTM D885. The above process was tested five times or more and then obtained from the average value. At this time, the tensile speed was 300 mm / min, and the super load was fineness x 1/30 g.

Average Winding time

In order to confirm the operability of the aramid fibers indirectly, the average winding time was measured. The average winding time was measured by measuring the time (Hr) wound on the branch of the winder continuously without cutting the filament (1), and averaged the 10 samples measured.

division Tensile strength (g / d) Shinto (%) Average winding time (Hr) Example 1 20.8 3.12 35.4 Example 2 21.2 3.21 36.7 Example 3 20.2 3.10 33.5 Example 4 20.1 2.75 29.6 Example 5 20.1 2.78 28.1 Example 6 20.9 2.32 24.5 Example 7 20.7 3.24 26.3 Example 8 20.5 3.10 31.2 Comparative Example 1 19.5 2.25 18.1 Comparative Example 2 19.2 2.12 15.2 Comparative Example 3 19.6 2.34 15.5 Comparative Example 4 17.2 2.10 6.2 Comparative Example 5 18.5 2.18 7.8 Comparative Example 6 18.1 2.05 8.2 Comparative Example 7 19.3 2.95 12.7 Comparative Example 8 19.2 2.84 11.3

As shown in Table 2 above, when the injection angle (θ) and the spraying speed (Vq) of the coagulating liquid 31 in the high-speed spinning is out of an appropriate range, the tensile strength and elongation are lowered, and the average winding time is lowered, indicating that productivity is lowered. Can be.

1: filament 10: spinneret
20: air gap 30: coagulation tank
31: coagulation liquid 40: coagulation tube
50: nozzle

Claims (5)

Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope;
Spinning the spinning dope through a spinneret; And
Including the step of solidifying the spun spinning dope through the coagulation tube communicated with the air gap, the coagulation tank and the bottom of the coagulation bath, to produce a filament,
At this time, the coagulation tube is provided with an injection hole communicating with the inside of the coagulation tube to inject a coagulation solution into the filament, the injection angle of the injection direction of the coagulation solution of the injection hole and the direction of the filament is 5 to 15 ° And, the ejection rate of the coagulating solution at the bottom outlet of the coagulation tube is 25 to 40% of the spinning rate. The method of claim 1,
The spinning speed is a method for producing aramid fibers, characterized in that 1,000 to 2,000 minutes / meter. The method of claim 1,
A method of producing aramid fibers further comprising the step of polymerizing an aromatic diamine and an aromatic dieside halide to produce the aromatic polyamide polymer. The method of claim 1,
The method of producing aramid fibers, characterized in that the average winding time of the filament is 24 hours or more. The method of claim 1,
The aramid fiber is a method for producing aramid fiber, characterized in that it has a tensile strength of 20 g / d or more.

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