KR20090104675A - Para Aramid Fiber and method of making the same - Google Patents

Abstract

PURPOSE: A manufacturing method of para-aramid is provided to improve tensile strength and elongation property by improving surface roughness characteristic through uniform forming of the aramid fiber surface. CONSTITUTION: A manufacturing method of para-aramid includes the following steps of: manufacturing an aromatic poly amide polymer by plasticizing aromatic diamine and aromatic family diacid halide; manufacturing spinning dope by dissolving the aromatic poly amide polymer in a solvent; and passing spinning dope through a spinneret. The filament is gained by spinning coagulant through an air gap(17), a coagulant bath(20), a spinneret(35), and a coagulation tube(30). The distance of the coagulant from the top of the coagulant bath and the spinneret in the coagulant tube is in a range of 10 ~ 35mm.

Description

Para Aramid Fiber and method of making the same

The present invention relates to a para aramid fiber, and more particularly to a high-strength para aramid fiber excellent in surface uniformity and a method for producing the same.

Aramid fibers include para-aramid fibers and meta-aramid fibers having a structure in which benzene rings are linearly connected through an amide group (CONH). Para-aramid fiber is 5mm thin and has a strong strength enough to lift 2 tons of cars. It is used not only for bulletproof but also for various applications in the high-tech industry of aerospace.

The aromatic polyamide fiber, collectively referred to as aramid fiber, is a step of producing an aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic dieside chloride in a polymerization solvent containing N-methyl-2-pyrrolidone, the aromatic polyamide polymer It is prepared through the process of preparing a spinning dope by dissolving in a concentrated sulfuric acid solvent, and the step of spinning the spinning dope through a spinneret and then solidifying the spinning material to produce a filament.

Such aramid fibers have a skin-core structure having a high elastic modulus of the surface layer compared to the elastic modulus of the center layer, and when stress is applied to the aramid fibers, stress is mostly concentrated on the surface layer. Therefore, the physical properties of the surface layer of aramid fibers are an important factor in determining the strength of aramid fibers. However, in the prior art, no management factor for the surface layer of aramid fibers has been considered, thereby limiting the strength of the aramid fibers.

The present invention has been devised to solve the above-mentioned conventional problems, and an object of the present invention is to provide a para-aramid fiber having a high strength characteristic and a method for producing the same by enhancing the surface uniformity of the aramid fiber.

Hereinafter, in this specification, "aramid fiber" refers to "para aramid fiber".

The inventors of the present invention, while studying a method for obtaining high-strength aramid fibers, it was confirmed that the surface uniformity of the aramid fibers affects the strength enhancement of the aramid fibers. That is, it was confirmed that the strength of the aramid fibers is improved as the surface uniformity of the aramid fibers is improved.

In addition, the present inventors conducted further studies to enhance the surface uniformity of the aramid fibers, and as a result, the present invention was confirmed that the surface uniformity of the aramid fibers can be improved by controlling the spinning process.

Specific technical means 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 passing the spinning dope through a predetermined spinneret, and then spinning the dope through a coagulation tube communicating with the bottom of the coagulation tank, the air gap, a coagulation tank in which coagulation liquid is stored, and an injection hole. In this case, the distance from the top of the coagulation solution stored in the coagulation bath to the injection port provided in the coagulation tube provides a method for producing para-aramid fibers, characterized in that the range of 10 to 35mm.

At this time, the distance from the lower end of the coagulation bath may be in the range of 5 to 20mm.

The distance from the top of the coagulation solution to the bottom of the coagulation bath may range from 5 to 15 mm.

The injection hole may be formed in plural with different heights, so that the coagulating liquid may be injected into the coagulation tube in multiple stages.

The ratio of the spraying speed of the coagulating liquid sprayed into the coagulation tube at the injection hole to the discharge rate of the filament discharged from the coagulation tube may be in the range of 0.8: 1 to 1.2: 1. The injection rate of the solid solution may be 150 to 800 mpm.

The coagulation solution stored in the coagulation bath may be made of sulfuric acid solution, wherein the concentration of sulfuric acid in the sulfuric acid solution may be 5 to 15% by weight, the temperature of the sulfuric acid solution may be in the range of 1 to 10 ℃.

The present invention has a structure in which an amide bond is bonded between the aromatic rings, the aromatic ring is linearly connected through the amide bond, the surface roughness is less than RMS 0.2㎛, tensile strength ranges from 22g / d to 26g / d It provides a para aramid fiber characterized in that.

Here, the aramid fibers may have an elongation of 2.8 to 3.5%.

The aramid fibers have a maximum seawater resistance of 5 N or less on a plain weave fabric having a weft and oblique fineness of 1500 denier and a weaving density of 260 g / m ² .

The present invention has an effect that the surface of the aramid fibers is uniformly formed by optimizing the spinning process (spinning) to improve the surface roughness characteristics, thereby excellent in tensile strength and elongation characteristics.

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

1. Preparation of Aromatic Polyamide Polymer

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, and these inorganic salts. 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.

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.

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 was initiated. 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 halide include terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalenedicarboxylic acid dichloride or 1,5-naphthalenedicarboxylic acid dichloride, but are not necessarily It is not limited.

Next, after the prepolymerization step is completed, the remaining amount of the aromatic dieside halide is added to the mixed solution while stirring at 0˜30 ° C. to polymerize.

In the production 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 may be added in the same molar ratio.

After completing the polymerization process, it is preferable to adjust the amount of aromatic diamine and dieside halide so that the concentration of the final polymer in the total polymerization solution is about 5 to 20% by weight. When the aromatic diamine and the dieside halide are added so that the concentration of the final polymer is less than 5% by weight, the polymerization rate is lowered and the reaction must be carried out for a long time. This is because when the diamine and the dieside halide are added, the polymerization does not proceed smoothly and the intrinsic viscosity of the polymer cannot be improved to 5.5 or more.

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).

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.

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.

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.

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 equipped with an outlet, placing a polymer on the filter, and then pouring water to discharge the polymerization solvent contained in the polymer together with water to the outlet.

Next, the water remaining after the extraction process is dehydrated, and then the aromatic polyamide polymer is manufactured through a drying process. Thereafter, a classification process may be performed to classify the aromatic polyamide polymers by size for the spinning process.

2. Preparation of Para Aramid Fiber

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.

The polymer concentration in the spin dope is preferably 10 to 25% by weight for the fiber properties. As the polyamide polymer concentration increases, the viscosity of the spin dope increases, but beyond the critical concentration point, the viscosity of the spin dope decreases rapidly, with the spin dope forming an optical phase without forming a solid phase. It changes from isotropic to optically anisotropic. Since the anisotropic spin dope can be made of high strength aramid fibers due to its structural and functional properties without a separate drawing process, it is preferable that the polyamide polymer concentration in the spinning dope exceeds the above critical concentration, but the concentration is excessively high. If large, the viscosity of the spinning dope is too low occurs.

Next, as can be seen in Figure 1, after passing the spin dope through a predetermined spinneret (10), an air gap (17), a coagulation bath (20) and a coagulation tube A filament 1 is formed by spinning through 30 in sequence.

The spinneret 10 has a plurality of capillaries 15 having a diameter of 0.1 mm or less. If the diameter of the capillary tube 15 formed in the spinneret 10 exceeds 0.1 mm, the molecular orientation of the resulting filament is deteriorated, resulting in a decrease in the strength of the filament.

The air gap 17 may also be mainly used in the air layer or inert gas layer, the length of the air gap is in the range of 2 to 20 mm is preferable for improving the physical properties of the filament to be produced.

The coagulation bath 20 is located at the bottom of the spinneret 10 and a coagulation liquid 22 is stored therein, and a coagulation tube 30 is formed at the bottom of the coagulation bath 20. The coagulation tube 30 is in communication with the bottom of the coagulation tank (20).

Therefore, the radiant passing through the capillary tube 15 of the spinneret 10 is solidified while sequentially passing through the air gap 17 and the coagulating liquid 22, and is discharged through the coagulation tube 30 while forming a filament. . In addition to the filament, the coagulation solution 22 is also discharged through the coagulation tube 30, so that the coagulation solution 20 must be continuously supplied to the coagulation bath 20 as much as the discharge liquid.

A jet opening 35 is formed in the coagulation tube 30 so that coagulation liquid is injected into the filament passing through the coagulation tube 30 through the injection hole 35. The injection holes 35 are formed in a plurality or annular around the coagulation tube 30, such injection holes 35 are preferably aligned so that the coagulation solution can be symmetrically injected with respect to the filament. The spraying angle of the coagulating solution is preferably 0 to 85 ° with respect to the axial direction of the filament, and particularly, in the commercial production process, a spraying angle of 20 to 40 ° is appropriate.

From the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30, more precisely, the distance L from the upper end of the injection hole 35 is 10. It is preferably in the range from 35 mm. If the distance L is less than 10 mm, the crystallization of the filament may be damaged because the coagulant may be injected in a state in which the filament is not sufficiently solidified. If the distance L exceeds 35 mm, the filament Since the coagulating solution may be injected in the state where the coagulation is completely solidified, the surface of the filament may be damaged. As such, the step of injecting the coagulating solution from the injection hole 35 should be performed in a state in which the filament is properly solidified. In consideration of this, the distance L is set in the range of 10 to 35 mm.

The distance L ₁ from the top of the coagulation solution 22 to the bottom of the coagulation bath 20 is preferably in the range of 5 to 15 mm. If the distance (L ₁ ) is less than 5mm it may be difficult to control the spinning process due to the vortex generated by the air, if the distance (L ₁ ) exceeds 15mm solidification of the filament in the coagulation tank 20 Too much can be made, it is difficult to set the formation position of the injection hole (35). That is, when a lot of filaments are solidified in the coagulation tank 20, the burden of setting the position of the injection hole 35 close to the top of the coagulation tube 35 so that the coagulant is injected before the filament is completely solidified In addition, when the injection hole 35 is set too close to the top of the coagulation tube 35, a problem may occur in which the injection is performed in a state in which the filament is insufficiently focused as described below.

It is preferable that the distance L ₂ from the lower end of the coagulation bath 20 to the injection hole 35, more precisely, to the upper end of the injection hole 35 is in the range of 5 to 20 mm. If the distance (L ₂ ) is less than 5mm, because the injection is made in the state of insufficient filament focusing may not be uniformly solidified to the filament, if the distance (L ₂ ) exceeds 20mm The pumping capacity for the coagulating liquid 22 stored in the bath 20 may be reduced. That is, when the coagulation solution is injected from the injection hole 35, a pressure difference occurs between the coagulation tank 20 and the coagulation tube 30, so that the coagulation liquid 22 stored in the coagulation tank 20 rapidly enters the coagulation tube 30. Pumped to move, if the injection port 35 is formed in a position too far from the bottom of the coagulation tank 20 will be the pumping capacity for such a coagulation liquid 22 is reduced.

The injection holes 35 may be formed in plural with different heights, so that the solidification liquid may be injected into the solidification tube 30 in multiple stages. As such, when the coagulating solution is sprayed in multiple stages, drag force applied to the filament can be dispersed, thereby making the surface of the filament uniform and improving the orientation to prevent the decrease in strength. It is prevented from escaping rapidly, which improves the uniformity of the surface.

On the other hand, the ratio of the spraying speed (V ₁ ) of the coagulating liquid injected from the injection hole 35 to the discharge rate (V ₂ ) of the filament (1) discharged from the coagulation tube 30 is 0.8: 1 to 1.2: It is preferable that it is the range of 1. The surface of the filament 1 is damaged when the difference between the injection speed V ₁ of the coagulating liquid sprayed from the injection hole 35 and the discharge speed V ₂ of the filament 1 discharged from the coagulation tube 30 increases. If the ratio (V ₁ : V ₂ ) of the speed between the _two is out of the above range, the surface damage of the filament is particularly increased. In consideration of the discharge rate of the filament (1), it is preferable that the injection speed of the coagulating liquid injected from the injection hole 35 is 150 to 800 mpm.

The coagulating solution 22 may be a sulfuric acid solution, preferably a solution in which sulfuric acid is added to water, ethylene glycol, glycerol, alcohol, or a mixture thereof. The spin dope passing through the spinneret 10 forms a filament while sulfuric acid is removed in the course of passing through the coagulating solution 22. At this time, if sulfuric acid is rapidly removed from the surface of the filament, the surface of the filament may solidify before the sulfuric acid contained in the filament escapes, and the uniformity of the filament may be reduced. The solid solution 22 is formed.

The concentration of sulfuric acid in the coagulation solution 22 is preferably 5 to 15% by weight. If the concentration of sulfuric acid is less than 5% by weight it can be rapidly removed sulfuric acid from the filament, if the concentration of sulfuric acid exceeds 15% by weight it may be difficult to escape the sulfuric acid from the filament.

The temperature of the coagulation liquid 22 is preferably in the range of 1 to 10 ℃. This is because sulfuric acid may be difficult to escape from the filament when the temperature of the coagulating solution 22 is less than 1 ° C, and sulfuric acid may rapidly escape from the filament when the temperature of the coagulating solution 22 exceeds 10 ° C. .

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

Sulfuric acid may remain in the filament produced by the spinning process. Thus, 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, primary washing with a sulfuric acid-containing filament with 0.3 to 1.3% of an aqueous caustic solution, followed by 0.01 to 0.1% of a thinner caustic solution You can do a second flush.

Next, a drying process is performed to control the moisture content remaining in the filament.

The drying process may control the time for which the filament is in contact with the heated drying roll, or the moisture content of the filament by adjusting the temperature of the drying roll.

On the other hand, a tension is applied to the filament during the spinning, washing, neutralizing, and drying process, and the optimum size of the tension applied to the filament during the drying process is about 0.1 to 3.0 gpd although it is determined by the overall spinning condition. It is preferable to dry the filament under the tension of. If the tension during drying is less than 0.1 gpd, the molecular orientation is reduced and ultimately the strength of the fiber is lowered. On the contrary, when the tension exceeds 3.0 gpd during drying, there is a fear that the filament is cut, which causes manufacturing difficulties. On the other hand, the magnitude of the tension applied to the filament can be adjusted by appropriately controlling the surface speed of the roll for moving the filament.

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.

Para aramid fibers according to the present invention obtained through such a process has an amide bond is bonded between the aromatic ring, the aromatic ring has a structure connected linearly through the amide bond, the surface roughness is less than RMS 0.2㎛ do. The small surface roughness value means that the surface uniformity is excellent, and the aramid fibers according to the present invention have excellent tensile strength of 22 g / d to 26 g / d because of excellent surface uniformity.

In addition, the aramid fibers according to the present invention has an elongation of 2.8 to 3.5%. When the surface of the fiber is not uniform, the fiber is easily cut during stretching. The aramid fiber according to the present invention is not easily cut during stretching because of the excellent uniformity of the surface and thus has a high elongation range.

In addition, the aramid fibers according to the present invention has a maximum seawater resistance of 5N or less on a plain weave fabric having a weft and oblique fineness of 1500 denier and a weaving density of 260 g / m ² . Maritime maximum resistance refers to the maximum resistance when weaving a fiber to obtain a textile and then pulling a strand of fiber from the fabric. When the surface of the fiber is uniform, the fiber is easily pulled out of the fabric. Becomes small. In other words, the smaller the sea-water resistance, the better the uniformity of the fiber surface.

3. Examples and Comparative Examples

1) Example 1

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. The polymer concentration in the spinning dope was adjusted to 20% by weight. Thereafter, the spinning dope was spun by using a spinning apparatus as shown in FIG. That is, after spinning the spinning dope through the spinneret 10, the coagulation tank 20 containing a sulfuric acid solution of 5 ℃ and 10% by weight as a 7mm air gap 17, a coagulation solution 22 and The filament was manufactured by solidifying while passing through the coagulation tube 30 at the bottom of the coagulation tank 20.

At this time, the distance (L) from the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30 is 20 mm, from the top of the coagulation solution 22. The distance L ₁ to the lower end of the coagulation bath 20 was set to 10 mm, and the distance L ₂ from the lower end of the coagulation bath 20 to the injection hole 35 was set to 10 mm.

In addition, the injection speed (V ₁ ) of the coagulation liquid injected from the injection port 35 and the discharge speed (V ₂ ) of the filament (1) discharged from the coagulation tube 30 were set to 600mpm.

Thereafter, the filament was washed with water to remove residual sulfuric acid, dried, and wound up to obtain 1500 denier aramid fibers.

2) Example 2

In Example 1 described above, the distance (L) from the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30 is 10mm, the coagulation solution 22 The distance L ₁ from the upper end of the coagulation bath 20 to the lower end of the coagulation bath 20 is 5 mm, except that the distance L ₁ from the lower end of the coagulation bath 20 to the injection hole 35 is set to 5 mm. And the aramid fiber was obtained by the method similar to Example 1 mentioned above.

3) Example 3

In Example 1 described above, the distance (L) from the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30 is 35 mm, the coagulation solution 22 Distance L ₁ from the upper end of the coagulation tank 20 to the lower end of the coagulation bath 20 is 15 mm, except that the distance L ₂ from the lower end of the coagulation bath 20 to the injection hole 35 is set to 20 mm. And the aramid fiber was obtained by the method similar to Example 1 mentioned above.

4) Example 4

In the above-described embodiment 1, the injection speed (V ₁ ) of the coagulating liquid injected from the injection hole 35 is set to 700mpm and the discharge speed (V ₂ ) of the filament (1) discharged from the coagulation tube 30 is Aramid fibers were obtained in the same manner as in Example 1 except that the amount was set to 600 mpm.

5) Example 5

In the above-described embodiment 1, the injection speed (V ₁ ) of the coagulating liquid injected from the injection hole 35 is set to 500mpm and the discharge speed (V ₂ ) of the filament (1) discharged from the coagulation tube 30 is Aramid fibers were obtained in the same manner as in Example 1 except that the amount was set to 600 mpm.

6) Comparative Example 1

In Example 1 described above, the distance (L) from the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30 is 8mm, the coagulation solution 22 The distance L ₁ from the upper end of the coagulation bath 20 to the lower end of the coagulation bath 20 is 5 mm, except that the distance L ₂ from the lower end of the coagulation bath 20 to the injection hole 35 is set to 3 mm. And the aramid fiber was obtained by the method similar to Example 1 mentioned above.

7) Comparative Example 2

In Example 1 described above, the distance (L) from the upper end of the coagulation solution 22 stored in the coagulation bath 20 to the injection hole 35 provided in the coagulation tube 30 is 40mm, the coagulation solution 22 Distance L ₁ from the upper end of the coagulation bath 20 to the lower end of the coagulation bath 20 is 15 mm, except that the distance L ₂ from the lower end of the coagulation bath 20 to the injection hole 35 is set to 25 mm. And the aramid fiber was obtained by the method similar to Example 1 mentioned above.

8) Comparative Example 3

In Comparative Example 2 described above, the injection speed (V ₁ ) of the coagulating liquid injected from the injection hole 35 is set to 400mpm and the discharge rate (V ₂ ) of the filament (1) discharged from the coagulation tube (30) is Aramid fibers were obtained in the same manner as in Comparative Example 2, except that the amount was set to 600 mpm.

9) Comparative Example 4

In Comparative Example 2 described above, the injection speed (V ₁ ) of the coagulating liquid injected from the injection hole 35 is set to 750mpm and the discharge rate (V ₂ ) of the filament (1) discharged from the coagulation tube (30) is Aramid fibers were obtained in the same manner as in Comparative Example 2, except that the amount was set to 600 mpm.

10) Comparative Example 5

In Comparative Example 1, aramid fibers were obtained in the same manner as in Comparative Example 1, except that the temperature of the coagulating solution 20, that is, the sulfuric acid solution contained in the coagulation bath 20 was maintained at 0 ° C.

11) Comparative Example 6

In Comparative Example 1, aramid fibers were obtained in the same manner as in Comparative Example 1, except that the temperature of the coagulating solution 20, that is, the sulfuric acid solution contained in the coagulation bath 20 was maintained at 15 ° C.

12) Comparative Example 7

In Comparative Example 1, aramid fibers were obtained in the same manner as in Comparative Example 1, except that the concentration of the coagulating solution 20, that is, the sulfuric acid solution contained in the coagulation bath 20 was maintained at 3% by weight.

13) Comparative Example 8

In Comparative Example 1, aramid fibers were obtained in the same manner as in Comparative Example 1, except that the concentration of the coagulating solution 20, that is, the sulfuric acid solution contained in the coagulation bath 20 was maintained at 20% by weight.

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

Table 1

L (mm) L ₁ (mm) L ₂ (mm) V ₁ (mpm) V ₂ (mpm) V ₁ : V ₂ Coagulation liquid temperature (℃) Coagulant concentration (% by weight) Example 1 20 10 10 600 600 1: 1 5 10 Example 2 10 5 5 600 600 1: 1 5 10 Example 3 35 15 20 600 600 1: 1 5 10 Example 4 20 10 10 700 600 1.17: 1 5 10 Example 5 20 10 10 500 600 0.83: 1 5 10 Comparative Example 1 8 5 3 600 600 1: 1 5 10 Comparative Example 2 40 15 25 600 600 1: 1 5 10 Comparative Example 3 40 15 25 400 600 0.67: 1 5 10 Comparative Example 4 40 15 25 750 600 1.25: 1 5 10 Comparative Example 5 8 5 3 600 600 1: 1 0 10 Comparative Example 6 8 5 3 600 600 1: 1 15 10 Comparative Example 7 8 5 3 600 600 1: 1 5 3 Comparative Example 8 8 5 3 600 600 1: 1 5 20

In Table 1 above,

L: Distance from the upper end of the coagulating liquid 22 to the injection hole 35,

L ₁ : distance from the upper end of the coagulation liquid 22 to the lower end of the coagulation bath 20,

L ₂ : distance from the lower end of the coagulation tank 20 to the injection hole 35,

V ₁ : is the injection speed of the coagulating liquid sprayed from the injection hole 35, and

V ₂ is the discharge rate of the filament 1 discharged from the coagulation tube 30.

4. Experimental Example

1) Surface roughness measurement of aramid fibers

After preparing each sample by cutting the aramid fibers according to the Examples and Comparative Examples to 25cm, the surface roughness of each sample was measured using AFM (Atomic Force Microscopy), a surface roughness measuring instrument.

Specifically, each sample is fixed well in a V-shaped groove of a substrate having a V-shaped groove, and then using a Nanoscope III a Multimode from Digital Instruments, UK. Surface roughness for each sample was measured. The results are shown in Table 2 below.

2) Tensile strength measurement of aramid fiber

After cutting the aramid fiber according to each Example and Comparative Example to 25cm to prepare each sample, the tensile strength was measured according to the ASTM D-885 test method.

Specifically, an Instron Engineering Corp (Canton, Mass) is used to measure the strength (g) when each sample breaks at a tensile rate of 300 mm / min and convert the measured value to the denier of the sample. The tensile strength (g / d) was obtained by dividing. The results are shown in Table 2 below.

3) Elongation Measurement of Aramid Fiber

The aramid fibers according to the respective examples and comparative examples were cut into 25 cm to prepare each sample, and the elongation of each sample was measured.

Specifically, using an Instron Engineering Corp. (Canton, Mass) to measure the elongated length when each sample breaks at a tensile rate of 300mm / min and dividing the measured value by the initial length of the sample to reduce the elongation (%) Was obtained. The results are shown in Table 2 below.

4) Maximum maritime resistance of aramid fibers

After weaving aramid fibers with a fineness of 1500 denier according to the Examples and Comparative Examples, weaving and warping, weaving into plain weave with a weaving density of 260 g / m ² , and preparing a fabric sample with a size of 80 mm x 80 mm, The maximum sea-resistance force at the time of pulling 1 strand of aramid fiber from the fabric sample was measured.

Specifically, using the Instron Engineering Corp. (Instron Engineering Corp, Canton, Mass) was measured the maximum strength (N) required to pull one strand of aramid fibers from each sample at a tensile rate of 300mm / min. The results are shown in Table 2 below.

TABLE 2

Surface Roughness (㎛) Tensile strength (g / d) Elongation (%) Maximum resistance at sea (N) Example 1 0.10 25.5 3.45 3.9 Example 2 0.18 22.9 3.15 4.9 Example 3 0.11 25.2 3.43 4.1 Example 4 0.13 24.1 3.27 4.3 Example 5 0.15 23.5 3.24 4.6 Comparative Example 1 0.25 21.5 2.75 5.2 Comparative Example 2 0.21 21.7 2.79 5.1 Comparative Example 3 0.28 21.2 2.71 5.5 Comparative Example 4 0.27 21.3 2.73 5.3 Comparative Example 5 0.27 21.4 2.72 5.4 Comparative Example 6 0.32 21.0 2.70 5.7 Comparative Example 7 0.35 20.5 2.64 5.9 Comparative Example 8 0.40 20.0 2.60 6.2

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

<Description of Signs of Major Parts of Drawing>

1: filament 10: spinneret

15: capillary 17: air gap

20: coagulation tank 22: coagulation liquid

30: coagulation tube 35: injection hole

Claims (11)

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 And passing the spinning dope through a predetermined spinneret, and then spinning the dope through a coagulation tube communicating with the bottom of the coagulation tank, the air gap, a coagulation tank in which coagulation liquid is stored, and an injection hole. Lose, At this time, the distance from the top of the coagulation solution stored in the coagulation bath to the injection port provided in the coagulation tube is a method for producing para-aramid fibers, characterized in that 10 to 35mm range. The method of claim 1, Method of producing a para aramid fiber, characterized in that the distance from the bottom of the coagulation bath to the injection port ranges from 5 to 20mm. The method of claim 1, The distance from the top of the coagulation solution to the bottom of the coagulation bath is a method for producing para-aramid fibers, characterized in that 5 to 15mm range. The method of claim 1, The injection hole is formed with a plurality of different heights, the method of producing para-aramid fibers, characterized in that for spraying the coagulation liquid in multiple stages inside the coagulation tube. The method of claim 1, The ratio of the injection rate of the coagulating liquid sprayed into the coagulation tube at the injection hole to the release rate of the filament discharged from the coagulation tube is in the range of 0.8: 1 to 1.2: 1. The method of claim 5, The injection speed of the coagulating liquid sprayed from the injection port is a method for producing para-aramid fibers, characterized in that 150 to 800 mpm. The method of claim 1, The coagulation solution stored in the coagulation bath is made of sulfuric acid solution, the concentration of sulfuric acid in the sulfuric acid solution is a method for producing para-aramid fibers, characterized in that 5 to 15% by weight. The method of claim 1, The coagulation solution stored in the coagulation bath is made of sulfuric acid solution, the temperature of the sulfuric acid solution is a method for producing para-aramid fibers, characterized in that the range of 1 to 10 ℃. An amide bond is bonded between the aromatic rings, the aromatic ring has a structure connected linearly through the amide bond, the surface roughness is less than RMS 0.2㎛, tensile strength is in the range of 22g / d to 26g / d Para aramid fiber made with. The method of claim 9, The aramid fibers are para-aramid fibers, characterized in that having an elongation of 2.8 ~ 3.5%. The method of claim 9, The aramid fiber is a para-aramid fiber, characterized in that the weft and warp fineness of 1500 denier and weaving density of 260g / m ² , the seaweed maximum resistance of 5N or less based on the plain fabric.

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