JP2010180493A - Method for producing aromatic copolyamide fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an aromatic copolyamide fiber having excellent mechanical properties such as high strength. <P>SOLUTION: The method for producing the aromatic copolyamide fiber having a composition of a specific range of a structural repeating unit (1) represented by formula (1) and a structural repeating unit (2) represented by formula (2), includes a spinning/solidifying step, a drawing step, and a heat treatment step. The drawing step uses a pair of rollers, arranges a guide bar on the perpendicular bisector of a tangent to the pair of rollers and draws a coagulated yarn while traveling the yarn so as to bring the yarn into contact with the guide bar. Consequently the tension is adjusted between the guide bar and the rollers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an aromatic copolyamide fiber excellent in tensile strength.

  Conventionally, an aramid fiber (fully aromatic polyamide fiber) mainly composed of an aromatic dicarboxylic acid component and an aromatic diamine component, particularly a para-aramid fiber, has characteristics such as strength, high elastic modulus, and high heat resistance. Therefore, it is widely used for various industrial materials and protective clothing such as bulletproof and blade-proof materials.

  As a typical para type aramid fiber, for example, polyparaphenylene terephthalamide (hereinafter referred to as “PPTA”) fiber is most known. This PPTA fiber has the above-described characteristics and is widely used in various fields. However, on the other hand, PPTA polymer becomes insoluble in a general-purpose organic solvent when a certain degree of polymerization is exceeded, so that a polymer dope using concentrated sulfuric acid as a solvent must be used, fiber properties such as tensile strength and Some drawbacks such as the point that the physical properties such as chemical resistance and light resistance cannot be said to be sufficiently high, and that the fiber easily fibrillates due to rubbing or the like have also been revealed.

  Therefore, in order to overcome the above-mentioned drawbacks, it exhibits high solubility in general-purpose amide solvents, can be spun without using concentrated sulfuric acid, and has high tensile strength and chemical resistance by drawing treatment in the yarn production process. Many developments of para-type copolyaramid fibers having light resistance and fibril resistance have been made.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 7-300534), a polymer that is soluble in an amide solvent is obtained by polycondensation of dicarbonyl dihalides and at least two kinds of diamines. Furthermore, a method for producing an aromatic copolyamide fiber or film using an isotropic polymer dope obtained by dissolving the polymer in a solvent has been reported.

  According to this method, fibers can be produced without using concentrated sulfuric acid as a solvent, and a certain degree of high strength has been achieved by stretching in the spinning process. However, sufficient study has not been conducted on the stretching process essential for increasing the strength, and as a result, the mechanical properties such as tensile strength and elastic modulus have not been sufficiently satisfactory.

  In Patent Document 2 (Japanese Patent Application Laid-Open No. 2006-207064), an aromatic copolymer obtained by reacting two kinds of diamines such as an aromatic dicarboxylic acid chloride, a para-type aromatic diamine, and an aromatic diamine having a phenylenebenzimidazole group. A method for producing polyamide fibers has been reported.

According to this method, a certain level of high strength can be achieved. However, sufficient studies have not been made on suitable stretching methods and conditions that focus on the variation of single fibers.
In view of such a current situation, development of an aromatic copolyamide fiber having higher strength has been highly desired.

Japanese Patent Laid-Open No. 7-300534 JP 2006-207064 A

  The present invention has been made against the background of the above-described prior art, and pays attention to a drawing method essential for yarn production using an isotropic polymer dope, and a method for producing an aromatic copolyamide fiber excellent in tensile strength. The purpose is to provide.

  The inventors of the present invention have made extensive studies to achieve this problem. And in the drawing using a pair of rollers, which is one of the general fiber drawing methods, the draw ratio is non-uniform for each single fiber constituting the fiber, and the strength and fineness of each single fiber vary. We focused on the fact that as a result, the strength of the fiber, which is an aggregate of single fibers, was not greatly improved. That is, when the single fiber constituting the fiber has a large variation, when the fiber composed of the single fiber is pulled, it starts preferentially from the single fiber having a low tensile strength, that is, finally the entire fiber It was speculated that the film was broken without maintaining high strength. Based on this assumption, the tensile strength of the fiber that is an aggregate of single fibers is maximized when the strength of the single fibers constituting the fibers is uniform, and therefore, the tensile strength unevenness and fineness unevenness of each single fiber are suppressed. Doing so can be one means for improving the tensile strength of the fibers that are aggregates of them.

  The present inventors have studied a method for making the tension applied to each single fiber in the fiber more uniform and making the draw ratio of each single fiber uniform based on such a point of focus. However, when the draw ratio is as small as 1.2 to 2.5 times as in the present invention, the tension unevenness of the single fibers constituting the fibers tends to increase the variation in tensile strength and fineness for each single fiber. There was a problem.

  Therefore, when stretching using a pair of rollers, a guide bar is placed in the middle of the rollers, and the fibers are in contact with this guide bar, and the tension is adjusted between the normal pair of rollers. As compared with the case, it was found that the tension can be adjusted between the roller and the guide bar and between the guide bar and the roller, so that the draw ratio, fineness and tensile strength of each single fiber are made uniform, and the present invention has been achieved.

  That is, the present invention is a method for producing an aromatic copolyamide fiber comprising a structural repeating unit (1) represented by the following formula (1) and a structural repeating unit (2) represented by the following formula (2). The content of the structural repeating unit (1) is 10 to 70 mol% with respect to the total amount of the structural repeating unit (1) and the structural repeating unit (2), and the content of the structural repeating unit (2) is A polymer dope obtained by dissolving an aromatic copolyamide of 90 to 30 mol% with respect to the total amount of the structural repeating unit (1) and the structural repeating unit (2) in an amide solvent is added to the coagulation liquid. A spinning / coagulation step for discharging and obtaining a coagulated yarn; a drawing step for drawing the coagulated yarn to obtain a drawn yarn; and a heat treatment step for heat-treating the drawn yarn, wherein the drawing step comprises a pair of rollers. The tangent perpendicular to the pair of rollers A guide bar arranged equally line, a process for producing an aromatic copolyamide fibers while traveling is to stretch in contact coagulation yarn guide bar.

(In the formulas (1) and (2), Ar ¹ and Ar ² are each independently an unsubstituted or substituted divalent aromatic group.)

  According to the present invention, since the tension applied to the single fiber in the fiber can be made uniform in the drawing step in the yarn production, the draw ratio, fineness, and tensile strength of each single fiber can be made equal, and as a result. The tensile strength of the fiber after heat treatment in which the single fibers are aggregated can be improved. The obtained aromatic copolyamide fiber can be usefully used for various industrial material applications, protective clothing applications such as bulletproof / bladeproof materials, and the like.

It is the schematic which shows an example of the apparatus of the process of extending | stretching the fiber in this invention.

<Aromatic copolyamide>
Hereinafter, embodiments of the present invention will be described in detail.
The aromatic copolyamide in the present invention is a polymer in which two or more kinds of divalent aromatic groups are directly linked by an amide bond, and is generally an aromatic dicarboxylic acid in an amide polar solvent according to a known method. Obtained by polycondensation reaction of acid dichloride and aromatic diamine. At this time, the aromatic group may be one in which two aromatic rings are bonded with oxygen, sulfur, or an alkyl group. In addition, these divalent aromatic rings may be unsubstituted or substituted with a lower alkyl group such as a methyl group or a methyl group, or a halogen group such as a methoxy group or a chlorine group. The type and the number of substituents are not particularly limited.

[Raw material of aromatic copolyamide]
(Aromatic dichloride)
In the aromatic copolyamide of the present invention, the aromatic dicarboxylic acid dichloride used in the structural repeating unit of the above formula (1) or formula (2) is, for example, terephthalic acid dichloride, 2-chloroterephthalic acid dichloride, 3-methylterephthalate. Acid dichloride, 4,4′-biphenyldicarboxylic acid dichloride, 2,6-naphthalenedicarboxylic acid dichloride, isophthalic acid dichloride and the like can be mentioned, and terephthalic acid dichloride is most preferable from the viewpoints of versatility and mechanical properties of fibers. One or more of these aromatic dicarboxylic acid dichlorides can be used, and the composition ratio is not particularly limited.

(First diamine)
Among the aromatic diamines in the present invention, the diamine (hereinafter also referred to as “first diamine”) used in the structural repeating unit (1) represented by the above formula (1) includes p-phenylenediamine, 2 -Chloro p-phenylenediamine, 2,5-dichloro p-phenylenediamine, 2,6-dichloro p-phenylenediamine, m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4, Although 4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone etc. can be mentioned individually or in 2 types or more, it is not limited to these.
Among these, as the first diamine component, p-phenylenediamine, m-phenylenediamine and 3,4'-diaminodiphenyl ether can be used alone or in combination of two or more.

(Second diamine)
Among the diamines used in the aromatic copolyamide, the diamine used in the structural repeating unit (2) represented by the above formula (2) (hereinafter also referred to as “second diamine”) is substituted or unsubstituted. 5 (6) -Amino-2- (4-aminophenyl) from the viewpoints of availability, tensile strength and initial modulus of the resulting fiber, etc. Benzimidazole is preferred.

(Composition of diamine)
In the present invention, at least one “first diamine” and “second diamine” are used to constitute the structural repeating units of the formulas (1) and (2). As the combination, from the viewpoints of versatility and mechanical properties of fibers, a first diamine such as paraphenylenediamine and a second diamine such as 5-amino-2- (4-aminophenylene) benzimidazole are used. A combination is most preferred.

  In the aromatic copolyamide of the present invention, the molar ratio of “first diamine” to “second diamine”, in other words, the molar ratio of structural repeating unit (1) to structural repeating unit (2) is And 10 to 70 mol% and 90 to 30 mol%, respectively, preferably 15 to 60 mol% and 85 to 40 mol%, more preferably 25 to 50 mol% and 75 to 50 mol%, respectively. When the composition ratio of the first diamine such as paraphenylene diamine is less than 10 mol%, not only the reaction solution becomes cloudy during the polycondensation reaction, but also the problem of lowering the workability of the yarn and the mechanical properties of the fiber obtained. is there. On the other hand, when the composition ratio of the first diamine such as paraphenylene diamine exceeds 90 mol%, the reaction solution does not become cloudy, but high mechanical properties cannot be obtained.

(solvent)
Next, examples of amide solvents used for the polymerization and spinning of the aromatic copolyamide of the present invention include N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”), N, N-dimethylformamide, N, N. -Dimethylacetamide, dimethylimidazolidinone and the like can be mentioned, and NMP is most preferable from the viewpoints of versatility, harmfulness, handleability, solubility in an aromatic copolyamide polymer, and the like.

<Polymer dope>
The polymer dope in the present invention refers to a polymer solution in which an aromatic copolyamide polymer is dissolved in a solvent that can be dissolved therein. If the solvent used in the polycondensation reaction between the aromatic dicarboxylic acid dichloride and the aromatic diamine is also a good solvent for the aromatic copolyamide polymer, the polymer after the polycondensation reaction is not isolated. It can be used as a polymer dope as it is. In addition, an inorganic salt can also be used as a dissolution aid for the purpose of increasing the solubility of the polymer in the solvent. Examples of the inorganic salt include, but are not limited to, calcium chloride and lithium chloride. Although the amount of the inorganic salt added to the polymer dope is not particularly limited, it is 3 to 10% by weight based on the polymer dope weight from the viewpoint of the effect of improving the polymer solubility and the solubility of the inorganic salt in the solvent. preferable.
The isotropic polymer dope in the present invention refers to a polymer dope that does not form a liquid crystal in a state where the polymer is dissolved in a solvent and does not have a specific directionality.

Next, the method of the present invention will be described.
<Polymerization of aromatic copolyamide>
In the present invention, an aromatic copolyamide polymer is first polymerized.
In this polymerization, a known polycondensation reaction is applied, an amide solvent such as NMP is added to a reaction vessel, and a first aromatic diamine such as paraphenylene diamine and a second diamine such as 5-amino is added thereto. 2- (4-Aminophenylene) benzimidazole is dissolved, and an aromatic dicarboxylic acid dichloride such as terephthalic acid dichloride is added thereto to start a polycondensation reaction. The amount of the aromatic diamine added at this time is such that when the total amount of the aromatic diamine is 100 mol%, the first diamine (paraphenylenediamine) is 10 to 70 mol%, and the second diamine (5-amino-2). -(4-aminophenylene) benzimidazole) is 90 to 30 mol%.

Moreover, the quantity of the aromatic dicarboxylic acid dichloride to add is 95-105 mol% with respect to aromatic diamine. When the aromatic dicarboxylic acid dichloride is less than 95 mol% and exceeds 105 mol%, the reaction with the aromatic diamine does not proceed sufficiently, and a high degree of polymerization cannot be obtained.
Thereafter, a polycondensation reaction between the aromatic diamine and the aromatic dicarboxylic acid dichloride is performed using a known stirrer. The reaction temperature and reaction time at this time can be appropriately adjusted while watching the progress of the polymerization.

After completion of the reaction, hydrochloric acid is generated in the system by the polycondensation reaction and the system becomes acidic. For the purpose of neutralization, an alkali such as calcium hydroxide is added. The amount of alkali added varies depending on the type of alkali and the amounts of aromatic diamine and aromatic dicarboxylic acid dichloride, but when calcium hydroxide is used, it is preferably 95 to 100 mol% with respect to the aromatic dicarboxylic acid dichloride. When calcium hydroxide is less than 95 mol%, neutralization cannot be carried out sufficiently, the inside of the system still shows acidity and causes depolymerization, which is not preferable. On the other hand, when it exceeds 100 mol%, the inside of the system shows alkali, which is also not preferable because it causes depolymerization.
The calcium chloride generated by the neutralization reaction can be used as it is as a solubilizing agent that enhances the dissolution of the produced polymer in the solvent, and therefore does not need to be removed from the system.

The aromatic copolyamide polymer thus obtained needs to contain 10 to 70 mol% and 90 to 30 mol% of the structural repeating units of the above formula (1) and the above formula (2), respectively, based on the total amount. There is. When the structural repeating unit (1) represented by the above formula (1) is less than 10 mol% based on the total amount, not only the reaction solution becomes cloudy during the polycondensation reaction, but also the workability of the yarn production and the resulting fiber machine There is a problem that the physical properties deteriorate. On the other hand, when the structural repeating unit (1) exceeds 90 mol% with respect to the total amount, it becomes difficult to obtain high mechanical properties although the reaction solution does not become cloudy.
In addition, the intrinsic viscosity of the aromatic copolyamide of the present invention (value measured at 30 ° C. for a solution having a polymer concentration of 0.5 g / dl in 98% concentration of sulfuric acid) is usually about 3.0 to 6.0. is there.

  The obtained aromatic copolyamide polymer is an isotropic polymer dope dissolved in an amide solvent such as NMP, and can be used as it is in the spinning process without isolation. However, the concentration of the aromatic copolyamide polymer at this time remarkably affects the viscosity and stability of the polymer dope, and greatly affects the spinnability and the like in the subsequent spinning process. Therefore, the polymer concentration is preferably 2 to 10% by weight. Therefore, an appropriate amount of NMP can be added to the obtained polymer dope for the purpose of adjusting the polymer concentration and viscosity.

<Method for producing aromatic copolyamide fiber>
Next, yarn production is performed using an aromatic copolyamide polymer dope.
[Spinning and coagulation process]
First, the polymer dope is discharged from the spinneret. The hole diameter and nozzle length of the spinneret used for discharging, and the ratio of the hole diameter and nozzle length are not particularly limited, and can be appropriately adjusted in consideration of the fiber diameter and spinnability of the resulting fiber. .
The material of the spinneret is not particularly limited as long as it is a material that does not corrode against amide solvents such as NMP. However, SUS316 is the most preferable from the viewpoint of versatility, workability of the hole of the die, and corrosion resistance. preferable.

The number of holes in the die is not particularly limited because it varies depending on the area and the hole diameter of the spinneret, and can be appropriately adjusted based on the number of single yarns of the desired fiber.
The temperature of the polymer dope when passing through the spinneret and the temperature of the spinneret are not particularly limited, but are preferably 80 to 120 ° C. from the viewpoint of spinnability and discharge pressure.

Next, the polymer dope discharged from the spinneret is coagulated in a coagulating liquid by a known semi-dry semi-wet spinning method. At this time, the length of the air gap is not particularly limited, but is preferably 5 to 15 mm from the viewpoints of temperature controllability and stringiness.
The coagulation liquid used here is preferably an NMP aqueous solution. The temperature and NMP concentration of the coagulation liquid are not particularly limited, and can be appropriately adjusted within a range in which there is no problem in the coagulation state of the discharged yarn and the subsequent process passability.

[Stretching process]
Next, in the drawing step, the coagulated yarn obtained above is drawn in an aqueous solution bath such as NMP other than the coagulating liquid used in the spinning / coagulation step to obtain a drawn yarn. The temperature and concentration of the aqueous solution such as NMP used at this time are not particularly limited, and can be appropriately adjusted as long as the yarn can be sufficiently plasticized and the stretchability can be obtained.

  In the stretching step, stretching is performed by using a pair of stretching rollers and providing a difference in the rotation speed of each stretching roller or the roller diameter. The difference in the rotation speed or roller diameter of the stretching roller can be appropriately adjusted in consideration of the number of turns to the stretching roller and the guide bar, the stretching ratio, and the like. In addition, extending | stretching is performed in the state in which half or more of roller diameters were immersed in aqueous solution, such as NMP.

  The draw ratio in the drawing step is preferably 1.2 to 2.5 times. When the draw ratio is less than 1.2 times, the molecular orientation does not proceed and a high-strength fiber cannot be obtained. On the other hand, when the draw ratio exceeds 2.5 times, a part or all of the single fiber constituting the fiber is cut, which is not preferable because the spinning workability is remarkably lowered and the tensile strength is also lowered accordingly.

FIG. 1 is an example of an apparatus capable of performing a series of operations in the stretching process of the present invention.
Hereinafter, the stretching process of the present invention will be described with reference to this drawing.
First, the coagulated yarn obtained by the spinning / coagulation step is passed through the drawing roller 1 from the left in the figure. Next, it is turned when passing through the stretching roller 2 and is directed again toward the stretching roller 1. At this time, the guides of the drawing roller 1 and the drawing roller 2 so that the center of the guide bar 5 is on the perpendicular bisector 4 with respect to the tangent line 3 of the two drawing rollers and at least contact with the traveling fiber. The bar 5 is placed and the fiber is run like 6. And it is made to turn with the extending | stretching roller 1, and is made to go to the extending | stretching roller 2 again. In this way, the fiber is drawn to the target draw ratio by turning a plurality of times.

The shape of the drawing roller and the guide bar used in the drawing process is a cylindrical roller having a perfect circular cross section, and the material is excellent in corrosion resistance to amide solvents such as water and NMP, and the fiber travels. The material is not particularly limited as long as the material does not wear out occasionally.
Moreover, it is preferable that a pair of extending | stretching roller has a motor which can control a rotational speed electrically, respectively.

As the guide bar, there is no particular problem even if a bar that has an electrically controllable rotational speed, has a bearing or the like inside, and rotates by physical force or does not rotate is used.
Although the diameter of a guide bar is not specifically limited, From a viewpoint of workability | operativity in an extending process, etc., it is preferable to have a diameter less than the diameter of an extending | stretching roller.

  Further, as the position of the guide bar, except that it is arranged so that the center of the guide bar 5 comes on the perpendicular bisector 4 with respect to the tangent line 3 of the two stretching rollers and at least touches the traveling fiber. It is not particularly limited, and can be appropriately adjusted from the tension applied to the running fiber, the uniformity of the draw ratio for each single fiber, and the like. Further, the guide bar may be disposed at a position perpendicular to the tangent line above the stretching roller.

[Washing process]
The drawn yarn obtained by the drawing step may be appropriately washed with water for the purpose of removing NMP in the fiber and the inorganic salt used as a dissolution aid. In addition, the liquid type and temperature in the washing bath in the washing step are not particularly limited, and there is no problem as long as NMP and the dissolution aid can be sufficiently removed.

[Drying process]
Next, the drawn yarn that has been subjected to water washing is dried in a drying step as necessary. The drying conditions at this time are not particularly limited, and there is no problem as long as the moisture attached to the fibers can be sufficiently removed. However, in consideration of workability and deterioration of the fibers due to heat, the temperature is 120 to 200 ° C. It is preferable to be in the range. For drying, a known drying apparatus such as a contact-type drying apparatus such as a roller or a non-contact type drying apparatus in which fibers pass through a drying furnace can be used as it is.

[Heat treatment process]
Next, the dried fiber is heat-treated. The heat treatment temperature is preferably in the range of 300 to 550 ° C, more preferably 320 ° C to 530 ° C, and most preferably 350 to 500 ° C. When the heat treatment temperature is less than 300 ° C., molecular orientation and crystallization do not progress, and high strength fibers cannot be obtained. On the other hand, when the heat treatment temperature exceeds 550 ° C., the tensile strength of the fiber is improved by molecular orientation and cross-linking between molecules, but the fiber is thermally deteriorated or thermally decomposed due to high temperature, which is not preferable. .
Although the atmosphere during the heat treatment is not particularly limited, it is preferably carried out in an inert gas such as nitrogen because there is a concern about oxidative degradation of the fiber.

Further, the tension of the fiber during the heat treatment is not particularly limited, but for the purpose of promoting the fiber orientation in this step, a tension is applied so that the single fiber and all of the fibers are not broken. Is preferred.
Further, since the single fibers constituting the fibers may be fused during the heat treatment, an inorganic substance or the like may be attached to the surface of the single fibers before the heat treatment for the purpose of suppressing the fusion.

<Physical properties of aromatic copolyamide fiber>
The aromatic copolyamide fiber thus obtained preferably has a tensile strength of 25 to 40 cN / dtex. In order to make the tensile strength of the resulting aromatic copolyamide fiber within the above range, a stretching method that can be uniform for each single fiber may be employed in the stretching step, and the stretching ratio, heat treatment temperature, etc. may be adjusted.

Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the scope of the present invention.
In addition, the physical property in a present Example etc. was measured and evaluated by the following method.

<Intrinsic viscosity of aromatic copolyamide>
The polymer was dissolved in 98% sulfuric acid so that the polymer concentration became 0.5 g / dl, and measured at 30 ° C. using an Ostwald viscometer.

<Fiber tensile strength, elongation at break, initial elastic modulus>
Using a tensile tester (manufactured by INSTRON, trade name: INSTRON, model: 5565 type), in accordance with ASTM D885, a yarn test chuck is used to perform a tensile test of the fiber under the following conditions, The elongation at break and the initial elastic modulus were measured respectively.
(Measurement condition)
Temperature: Room temperature Sample length: 75cm
Chuck pulling speed: 250 mm / min Distance between chucks: 500 mm
Initial load: 0.2 cN / dtex

<Fineness of single fiber>
Single yarns were taken out from the obtained fibers, and the fineness was measured under the following conditions, and the average value and the difference between the maximum value and the minimum value were determined.
(Measurement condition)
Temperature: Room temperature Testing machine: Denier computer DC-11B (manufactured by Search)
Test piece: 50 mm
Test length: 25 mm
Number of tests: 100

<Strength of single fiber>
A single yarn was taken out from each of the obtained fibers, and the tensile strength was measured under the following conditions to determine the average value and the difference between the maximum value and the minimum value.
(Measurement condition)
Temperature: Room temperature Testing machine: Single yarn tensile testing machine TSM-01 (manufactured by Search)
Test piece: 50 mm
Test speed: 20 mm / min Distance between chucks: 20 mm
Number of tests: 100

[Example 1]
(Manufacture of polymer dope)
Nitrogen was fed into a stirring tank having a stirring blade for replacement, and then 97 parts by weight of NMP was charged. To this was added 3 parts by weight of calcium chloride that had been sufficiently dried to remove moisture, and the calcium chloride was completely dissolved while stirring. Next, 0.5 parts by weight of paraphenylenediamine and 2.4 parts by weight of 5-amino-2- (4-aminophenylene) benzimidazole were added and completely dissolved while stirring. In addition, when the total amount of aromatic diamine was 100 mol%, the proportions of paraphenylenediamine and 5-amino-2- (4-aminophenylene) benzimidazole were 30 mol% and 70 mol%, respectively.

  After the aromatic diamine was completely dissolved, 3.1 parts by weight of terephthalic acid dichloride was added to carry out a polycondensation reaction. The amount of terephthalic acid dichloride added was 100 mol% with respect to the aromatic diamine. Moreover, the reaction temperature and reaction time at this time were 85 degreeC and 30 minutes, respectively. By this polycondensation reaction, an aromatic copolyamide polymer was produced, and a polymer dope was obtained.

Subsequently, for the purpose of neutralizing the obtained polymer dope, 5 parts by weight of NMP dispersion of 22.5% by weight calcium hydroxide was added to the polymer dope, and the neutralization reaction was performed, so that it was used for yarn production. Sex polymer dope was obtained.
In addition, the intrinsic viscosity of the obtained aromatic copolyamide was 5.05.

(Manufacture of aromatic copolyamide fiber)
Next, a polymer dope heated to 105 ° C. was discharged from a spinneret heated to 105 ° C. made of SUS316 having a hole diameter of 0.1 mm, a nozzle length of 0.6 mm, and a number of holes of 100, and through a 10 mm air gap. And passed through a coagulation bath having an NMP concentration of 40% by weight and 50 ° C. to obtain a coagulated yarn.

Next, a pair of rollers having a diameter of 10 cm and a distance of the center of each roller of 30 cm are arranged in an NMP aqueous solution bath having an NMP concentration of 65% by weight and 10 ° C., and further centered on the tangent line of the pair of rollers. In this bath, a non-rotating guide bar having a diameter of 1 cm is disposed so that the obtained coagulated yarn is wound around the pair of rollers and the guide bar, and the rotation speed of the rollers is controlled. The film was stretched 8 times.
The drawn fiber was washed with water in a water bath and then dried with a drying roller at 130 ° C. to obtain a dried yarn.

  Next, the obtained dried yarn was heat-treated in a heat treatment furnace at 450 ° C. in a nitrogen atmosphere to obtain a fiber having a fineness of 300 dtex and a filament count of 100. Table 1 shows the tensile strength, elongation at break, initial elastic modulus of the obtained fiber, average values of fineness and tensile strength of single fibers, and the difference between the maximum value and the minimum value.

[Example 2]
(Manufacture of aromatic copolyamide fiber)
Using the polymer dope obtained in Example 1, a pair of rollers having a diameter of 10 cm and a distance between the centers of the respective rollers of 30 cm is arranged, and the diameter is 5 cm so that the center comes on the tangent line of the pair of rollers. A non-rotating guide bar is arranged, and the fineness is 300 dtex and the number of filaments is 100 by the same method as in Example 1 except that the coagulated yarn is wound around the pair of rollers and the guide bar and drawn. Fiber was obtained.
Table 1 shows the tensile strength, elongation at break, initial elastic modulus of the obtained fiber, average value of fineness and tensile strength of the single fiber, and the difference between the maximum value and the minimum value.

[Comparative Example 1]
(Manufacture of aromatic copolyamide fiber)
A fiber having a fineness of 300 dtex and a filament count of 100 was obtained in the same manner as in Example 1 except that the polymer dope obtained in Example 1 was used and stretching was performed without arranging a guide bar.
Table 1 shows the tensile strength, elongation at break, initial elastic modulus of the obtained fiber, average value of fineness and tensile strength of the single fiber, and the difference between the maximum value and the minimum value.

[Comparative Example 2]
(Manufacture of polymer dope)
The amount of aromatic diamine added was 0.1 parts by weight of paraphenylene diamine and 3.6 parts by weight of 5-amino-2- (4-aminophenylene) benzimidazole, and the molar ratio was 5 mol%, 95 A polymer dope was obtained in the same manner as in Example 1 except that the polycondensation reaction was carried out in mol%. In addition, the intrinsic viscosity of the obtained aromatic copolyamide was 5.21.

(Manufacture of aromatic copolyamide fiber)
Using the obtained polymer dope, a fiber having a fineness of 300 dtex and a filament count of 100 was obtained in the same manner as in Example 1.
Table 1 shows the tensile strength, elongation at break, initial elastic modulus of the obtained fiber, average value of fineness and tensile strength of the single fiber, and the difference between the maximum value and the minimum value.

[Comparative Example 3]
(Manufacture of polymer dope)
The aromatic diamine was added in an amount of 1.4 parts by weight of paraphenylenediamine and 0.9 parts by weight of 5-amino-2- (4-aminophenylene) benzimidazole. A polymer dope was obtained in the same manner as in Example 1 except that the polycondensation reaction was carried out in mol%. In addition, the intrinsic viscosity of the obtained aromatic copolyamide was 5.22.

(Manufacture of aromatic copolyamide fiber)
Using the obtained polymer dope, a fiber having a fineness of 300 dtex and a filament count of 100 was obtained in the same manner as in Example 1.
Table 1 shows the tensile strength, elongation at break, initial elastic modulus of the obtained fiber, average value of fineness and tensile strength of the single fiber, and the difference between the maximum value and the minimum value.

  The aromatic copolyamide fiber obtained by the present invention is particularly useful for various industrial material applications that require high strength, high elastic modulus, high heat resistance and the like, and for protective clothing applications such as bulletproof and blade-proof materials.

1: Stretching roller 2: Stretching roller 3: Tangent line of two stretching rollers 4: Vertical bisector with respect to the tangent line of the stretching roller 5: Guide bar 6: Fiber during traveling in the stretching process

Claims (5)

A method for producing an aromatic copolyamide fiber comprising a structural repeating unit (1) represented by the following formula (1) and a structural repeating unit (2) represented by the following formula (2):
The content of the structural repeating unit (1) is 10 to 70 mol% based on the total amount of the structural repeating unit (1) and the structural repeating unit (2), and the content of the structural repeating unit (2) is A polymer dope obtained by dissolving 90-30 mol% of an aromatic copolyamide in an amide solvent with respect to the total amount of the repeating unit (1) and the structural repeating unit (2) is discharged into a coagulation liquid. Spinning and coagulation process to obtain coagulated yarn
A drawing step of drawing the coagulated yarn to obtain a drawn yarn;
A heat treatment step of heat treating the drawn yarn,
The drawing step uses a pair of rollers, arranges a guide bar on a perpendicular bisector of a tangent to the pair of rollers, and draws the coagulated yarn while running so as to contact the guide bar. A method for producing an aromatic copolyamide fiber.
(In the formulas (1) and (2), Ar ¹ and Ar ² are each independently an unsubstituted or substituted divalent aromatic group.)   The method for producing an aromatic copolyamide fiber according to claim 1, wherein the aromatic copolyamide polymer dope is an isotropic solution.   The method for producing an aromatic copolyamide fiber according to claim 1 or 2, wherein a draw ratio in the drawing step is 1.2 to 2.5 times.   The method for producing an aromatic copolyamide fiber according to any one of claims 1 to 3, wherein a heat treatment temperature in the heat treatment step is 300 to 550 ° C.   The tensile strength of the obtained aromatic copolyamide fiber is 25-40 cN / dtex, The manufacturing method of the aromatic copolyamide fiber in any one of Claims 1-4.