KR20090104600A - Aromatic Polyamide polymer and Method of making the same, and Aramid Fiber and method of making the same - Google Patents

Abstract

PURPOSE: An aromatic polyamide polymer and a method for preparing the same are provided to improve color property of the obtained aromatic polyamide polymer, thereby improving color property of final aramid fiber. CONSTITUTION: A method for preparing an aromatic polyamide polymer comprises the steps of: preparing a polymerization solvent; preparing a mixed solution by dissolving aromatic diamine in a polymerization solvent; and polymerizing aromatic diamine and aromatic diacid halide by adding aromatic diacid halide to the mixed solution. The molar ratio of the aromatic diamine of aromatic diacid halide is 1:1 ~ 0.98:1.

Description

Aromatic Polyamide polymer and Method of making the same, and Aramid Fiber and method of making the same

The present invention relates to aramid fibers, and more particularly, to aramid fibers with improved color characteristics and a method for producing the same.

Generally, the aromatic polyamide fiber, commonly 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 The polyamide polymer is prepared by dissolving a polyamide polymer in a concentrated sulfuric acid solvent to prepare a spinning dope, and spinning the spinning dope through a spinneret and then solidifying the spinning material to produce a filament.

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 has excellent properties such as high strength, high elasticity, and low shrinkage. It is a thin thread of about 5mm thick and has a strong strength enough to lift 2 tons of cars. It is used in various industries in the high-tech industry. In addition, aramid fibers are carbonized at 500 ° C or higher, and thus are attracting attention in fields requiring high heat resistance.

Such aramid fiber is a special fiber having high performance properties, and its application fields are various. However, conventional aramid fiber has a deteriorated color characteristic even if the physical properties are deteriorated or the physical properties are deteriorated. There was a limit to falling.

The present invention has been devised to solve the above-described problems, and the present invention relates to an aromatic polyamide polymer for producing aramid fibers having improved color characteristics, a method for producing the same, and a method for producing aramid fibers using the method, and to the method It is an object to provide aramid fibers produced by.

The present invention, to achieve the above object, a step of preparing a polymerization solvent; Dissolving aromatic diamine in the polymerization solvent to prepare a mixed solution; And adding an aromatic dieside halide to the mixed solution to polymerize the aromatic diamine and an aromatic dieside halide, wherein the molar ratio of the administered aromatic diamine and the aromatic dieside halide is 1: 1 to 0.98. Provided is a method for producing an aromatic polyamide polymer, characterized in that: 1.

The present invention also provides an aromatic polyamide polymer characterized in that the proportion of chain ends terminated with an acid is greater than the proportion of chain ends terminated with amines and has an L value in the range of 75 to 90.

The present invention also provides a process for preparing an aromatic polyamide polymer having an L-value in the range of 75 to 90, wherein the proportion of chain ends terminated with an acid is greater than that of chain ends terminated with amines; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; And it provides a method for producing aramid island oil comprising the step of spinning the spinning dope.

The present invention is also characterized in that the amide bond is bonded at least 85% between the aromatic rings, the ratio of the chain ends terminated by the acid is greater than the ratio of the chain ends terminated by the amine, and the L value ranges from 75 to 90. Provide aramid fibers.

The inventors of the present invention, while studying a method for obtaining aramid fibers with improved color properties, it was confirmed that the color properties of the aromatic polyamide polymer has a significant effect on the color properties of the finally obtained aramid fibers. Therefore, further studies have been conducted to improve the color properties of aromatic polyamide polymers. As a result, the color properties of aromatic polyamide polymers obtained by changing the molar ratio of aromatic diamines and aromatic dieside halides, which are raw materials of aromatic polyamide polymers, have been studied. It was confirmed that the improvement can be completed the present invention.

Specifically, the aromatic polyamide polymer obtained by polymerizing an aromatic diamine and an aromatic dieside halide may be terminated with an amine or terminated with an acid. In this case, when the chain ends are terminated with an amine, the amine may be oxidized to be changed to NO 2. Thus, when the amine is changed to NO 2, the color of the polymer becomes black. Therefore, in the present invention, the molar amount of the aromatic diamine is not greater than the molar amount of the aromatic dieside halide, so that the ratio of the chain terminal terminated to the acid is greater than that of the amine terminated chain in the aromatic polyamide polymer obtained through the polymerization reaction. The color of the aromatic polyamide polymer is to be prevented from discoloring to black.

In particular, when the aromatic diamine and the aromatic dieside halide are polymerized by administering a molar ratio of 1: 1 to 0.98: 1, the L value of the obtained aromatic polyamide polymer has a range of 75 to 90, and such an aromatic polyamide polymer When the aramid fibers are produced by spinning, the L-value of the resulting aramid fibers has a range of 75 to 90, thereby improving the color characteristics of the aramid fibers.

In addition, in order to obtain an aromatic polyamide polymer, after the polymerization reaction of the aromatic diamine and the aromatic dieside halide, a neutralization process, a crushing process, an extraction process, a dehydration and a drying process are continuously performed. In the process equipment inside the lighting device for ensuring the field of view is installed, it was confirmed that the color characteristics of the aromatic polyamide polymer due to the lighting device.

Specifically, when the sunlight is irradiated inside the process equipment or when a fluorescent lamp is used as the lighting device inside the process equipment, the color of the aromatic polyamide polymer is changed to a black series, but the sunlight is irradiated inside the process equipment. When the UV lamp was used as a lighting device inside the process equipment, the color of the aromatic polyamide polymer was not discolored. Therefore, the present invention is an additional feature to improve the color characteristics of the polymer by using an ultraviolet lamp as a lighting device for securing the view inside the process equipment after the polymerization process.

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

First, the present invention improves the color characteristics of an aromatic polyamide polymer obtained by administering an aromatic diamine and an aromatic dieside halide so as to have a molar ratio of 1: 1 to 0.98: 1, thereby polymerizing the aromatic polyamide polymer and spinning the aromatic polyamide polymer. By producing the fibers, the color properties of the resulting aramid fibers are improved.

Second, the present invention improves the color characteristics of the aromatic polyamide polymer obtained by using an ultraviolet lamp as an illuminating device for securing the inside of the process equipment after the process of polymerizing the aromatic diamine and the aromatic dieside halide. By spinning the polyamide polymer to produce aramid fibers, the color properties of the resulting aramid fibers are improved.

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, and these inorganic salts. Silver may be added alone or in the form of a mixture of two or more thereof. 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 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.

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.

Here, the remaining amount of the aromatic dieside halide is added so that the molar ratio of the aromatic diamine and the aromatic dieside halide is 1: 1 to 0.98: 1.

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, so the economical efficiency is lowered, and the concentration of the aromatic is greater than 20% by weight 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).

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, Li2CO3, CaCO3, LiH, CaH2, LiOH, Ca (OH) 2, Li2O or CaO, carbonate of alkaline earth metal, hydride of alkaline earth metal, hydroxide of alkaline earth metal, or oxide of alkaline earth metal It is selected from the group consisting of.

To secure the view inside the process equipment for such a neutralization process uses an ultraviolet lamp.

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.

To secure the view inside the process equipment for such a crushing process using an ultraviolet lamp.

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.

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.

The use of ultraviolet lamps to secure the field of view inside the process equipment for such extraction process.

8) Next, water remaining after the extraction process is dewatered, and then drying is completed to prepare the aromatic polyamide polymer. Thereafter, a classification process may be performed to classify the aromatic polyamide polymers by size for the spinning process.

To secure the view inside the process equipment for such a dehydration process and drying process using an ultraviolet lamp.

The finally obtained aromatic polyamide polymer has a greater proportion of acid-terminated chain ends than amine-terminated chain ends, and has an L value in the range of 75 to 90.

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.

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 radiation dope increases as well, but beyond the critical concentration point, the viscosity of the radiation dope decreases rapidly, in which the radiation dope does not form a solid phase. From optically 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 concentration of the polyamide polymer 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.

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 to the filament, the coagulation solution is discharged through the coagulation tube, so that the coagulation solution must be continuously supplied to the coagulation bath as much as the discharge liquid.

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 plurality of injection holes are preferably aligned so that the coagulating liquid can be sprayed in perfect symmetry with respect to the filament. The spray angle of the coagulating liquid is preferably 0 to 85 ° with respect to the axial direction of the filament, and particularly, in the commercial production process, a spray angle of 20 to 40 ° is appropriate.

The coagulating solution may be added sulfuric acid to water, ethylene glycol, glycerol, alcohol, or a mixture thereof, and is maintained at -20 to +90 ℃. When the radiation passed through the spinneret passes through the coagulating solution, the sulfuric acid in the emission is removed and filaments are formed. When sulfuric acid is rapidly removed from the surface, the surface is solidified before the sulfuric acid contained therein escapes. 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.

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.

4) Next, a drying process is performed to control the water 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.

Meanwhile, a tension is applied to the filament during the spinning, washing, neutralizing, and drying process, and the optimum magnitude of the tension applied to the filament during the drying process is about 3.0 to 7.0 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 3.0 gpd, the molecular orientation is reduced and ultimately the strength of the fiber is lowered. On the contrary, when the tension in drying exceeds 7.0 gpd, 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.

5) Next, the dried filament is wound on the branch pipe. The resulting aramid fiber has an amide bond of at least 85% bonded between the aromatic rings, the ratio of the chain ends terminated by the acid is greater than the ratio of the chain ends terminated by the amine, and has an L value in the range of 75 to 90. Characteristics are improved.

3. Example  And Comparative example

CaCl 2 was added to N-methyl-2-pyrrolidone (NMP) to prepare a polymerization solvent.

Thereafter, para-phenylenediamine was dissolved in the polymerization solvent to prepare a mixed solution. Thereafter, while stirring the mixed solution, terephthaloyl dichloride was added to the mixed solution in various molar ratios as described below in Table 1 with respect to the para-phenylenediamine in poly (paraphenylene terephthalamide). The polymer was produced. 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. At this time, in the process equipment for the neutralization process, the crushing process, the extraction process, the dehydration and drying process as shown in Table 1 to secure the field of view by using a fluorescent lamp or an ultraviolet lamp as a lighting device.

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 through a spinneret, passed through a 7 mm air layer, and coagulated while passing through a coagulation bath containing a sulfuric acid aqueous solution and a coagulation tube below the coagulation bath to prepare a filament. 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, dried, and wound up to obtain aramid fibers.

division Moles of paraphenylenediamine to moles of terephthaloyl dichloride Lighting equipment Example 1 0.98: 1 Fluorescent lamp Example 2 0.98: 1 UV lamp Example 3 1: 1 Fluorescent lamp Example 4 1: 1 UV lamp Comparative Example 1 1.02: 1 Fluorescent lamp Comparative Example 2 1.02: 1 UV lamp

4. Experimental Example

1) Determination of L value of aromatic polyamide polymer

Samples of the aromatic polyamide polymer obtained during the production process according to Examples 1 to 4 and Comparative Examples 1 to 2 were obtained, and each sample was prepared using a colorimeter (manufacturer: Minolta) whose model name was Chromater CR-300. The L value for was measured. The results are shown in Table 2.

division L value Example 1 83 Example 2 87 Example 3 77 Example 4 82 Comparative Example 1 60 Comparative Example 2 71

2) L value measurement of aramid fibers

For aramid samples prepared according to Examples 1 to 4 and Comparative Examples 1 to 2, the L value for each sample was measured using a colorimeter (manufacturer: Minolta) whose model name was Chromater CR-300. It was. The results are shown in Table 3.

division L value Example 1 83 Example 2 87 Example 3 77 Example 4 82 Comparative Example 1 60 Comparative Example 2 71

Claims (11)

Preparing a polymerization solvent; Dissolving aromatic diamine in the polymerization solvent to prepare a mixed solution; And Adding an aromatic dieside halide to the mixed solution to polymerize the aromatic diamine and an aromatic dieside halide, At this time, the molar ratio of the aromatic diamine and the aromatic dieside halide to be administered is 1: 1 to 0.98: 1 method for producing an aromatic polyamide polymer. The method of claim 1, After the polymerization reaction, Neutralizing the acid generated during the polymerization reaction; Grinding the polymer produced through the polymerization reaction; Extracting the polymerization solvent contained in the polymer; And Further comprising a dehydration and drying process, At this time, the neutralizing process, the grinding process, the extraction process, the dehydration and drying process, the method of producing an aromatic polyamide polymer, characterized in that using a UV lamp to secure the field of view inside the process equipment. The method according to claim 1 or 2, Process for producing an aromatic polyamide polymer, characterized in that the polymer obtained through the process has an L value in the range of 75 to 90. An aromatic polyamide polymer characterized in that the ratio of the chain ends terminated by the acid is greater than the ratio of the chain ends terminated by the amine, and has an L value in the range of 75 to 90. The method of claim 4, wherein The aromatic polyamide polymer is prepared by administering an aromatic diamine and an aromatic dieside halide in a polymerization solvent such that the molar ratio is 1: 1 to 0.98: 1 and then polymerizing the aromatic polyamide polymer. The method of claim 4, wherein The aromatic polyamide polymer is prepared by the method according to claim 1 or 2. Preparing an aromatic polyamide polymer having a ratio of chain ends terminated by an acid to a ratio of chain ends terminated by an amine and having an L value ranging from 75 to 90; Dissolving the aromatic polyamide polymer in a solvent to prepare a spinning dope; And Method for producing aramid fiber comprising the step of spinning the spinning dope. The method of claim 7, wherein The process for producing the aromatic polyamide polymer is a method for producing aramid fibers, characterized in that consisting of the method according to claim 1 or 2. The method of claim 6, The aramid fiber is a method for producing aramid fiber, characterized in that it has an L value in the range of 75 to 90. An aramid fiber characterized in that the amide bond is bonded at least 85% between the aromatic rings, the ratio of the chain ends terminated by the acid is greater than the ratio of the chain ends terminated by the amine, and the L value is in the range of 75 to 90. The method of claim 10, The aramid fibers are administered in an polymerization solvent such that the aromatic diamine and the aromatic dieside halide are in a molar ratio of 1: 1 to 0.98: 1, followed by polymerization to prepare an aromatic polyamide polymer having an L value in the range of 75 to 90, Aramid fibers, characterized in that produced by spinning the aromatic polyamide polymer.