JP6514010B2 - Process for producing para-type wholly aromatic copolyamide drawn fiber - Google Patents

Description

  The present invention relates to para-type wholly aromatic copolyamide drawn fibers and a method for producing the same. More particularly, the present invention relates to a para-type wholly aromatic copolyamide drawn fiber having high tensile modulus and a method for producing the same.

Conventionally, para-type wholly aromatic polyamide fibers mainly composed of an aromatic dicarboxylic acid component and an aromatic diamine component have various properties such as high tensile strength, high elastic modulus, high heat resistance, etc. It is widely used in applications and protective clothing applications such as bulletproof and blade-proof materials.
Typical para-type wholly aromatic polyamide fibers include, for example, polyparaphenylene terephthalamide (hereinafter referred to as PPTA) fibers, and PPTA fibers are used in a wide range of applications because they have the above-mentioned characteristics.

  However, PPTA polymers become insoluble in general-purpose organic solvents when the intrinsic viscosity (hereinafter sometimes referred to as IV) reaches a certain value or higher, and therefore, in the production of yarn, polymers polymerized in general-purpose organic solvents are once The isolated polymer has to be dissolved in concentrated sulfuric acid to form a dope, which causes problems in terms of safety, environment and the like. Furthermore, with regard to fiber physical properties, tensile strength, chemical resistance, light resistance and the like are not sufficiently high, and furthermore, there are some problems such as easy fibrillation of fibers due to abrasion and the like.

Therefore, it is possible to obtain a para-type wholly aromatic copolyamide fiber having high tensile strength, chemical resistance, light resistance, and fibril resistance by spinning without using concentrated sulfuric acid and by stretching or heat treatment in a spinning process. Manufacturing methods have been proposed.
For example, Patent Documents 1, 2 and 3 disclose a method of polymerizing para-type wholly aromatic polyamide using a general-purpose amide solvent and using the polymer solution dissolved in the amide solvent as it is to produce a fiber. Have been described. However, the para-type wholly aromatic copolyamide fibers described in Patent Documents 1, 2 and 3 can not yet exhibit sufficiently high mechanical properties, and in particular, they are not satisfactory in terms of tensile modulus. The

Japanese Patent Application Laid-Open No. 07-300534 JP, 2006-207064, A JP 2007-154328 A

The present invention has been made on the background of such prior art, and an object of the present invention is to provide a method of producing para-type wholly aromatic copolyamide drawn fiber which is very excellent in tensile modulus.

  The present inventors diligently studied to solve the above problems. The inventors have found that the above problems can be solved by subjecting a raw material fiber obtained from a para-type wholly aromatic copolyamide of a specific structure to high tension thermal drawing under a specific range of tension and temperature, and have completed the present invention .

That is, the present invention is a para-type wholly aromatic copolyamide fiber including the structural repeating unit of the following chemical structural formula (1) and the following chemical structural formula (2) , and of the para-type wholly aromatic copolyamide drawn fiber A method for producing a para-type wholly aromatic copolyamide drawn fiber having a tensile modulus of 1000 cN / dtex or more ,
Para-type wholly aromatic copolyamide base fiber obtained by wet spinning or semi-dry and semi-wet spinning of para-type wholly aromatic copolyamide solution is 1% or more with respect to breaking tension of para-type wholly aromatic copolyamide base fiber It is a method for producing a para-type wholly aromatic copolyamide drawn fiber, comprising a high tension heat drawing step of heat drawing at a temperature of 50 ° C. or more and 450 ° C. or less under a tension of less than 20% .

（Ａｒ^１およびＡｒ^２は独立であり、非置換あるいは置換された２価の芳香族基である。）

(Ar ¹ and Ar ² are independent and are unsubstituted or substituted divalent aromatic groups.)

（Ａｒ^１は非置換あるいは置換された２価の芳香族基である。）

(Ar ¹ is a substituted or unsubstituted divalent aromatic group)

  The para-type wholly aromatic copolyamide fiber of the present invention is a fiber excellent in tensile modulus. For this reason, the fiber of the present invention is very useful in protective clothing applications such as bulletproof and blade-proofing materials and various other industrial material applications.

Hereinafter, embodiments of the present invention will be described in detail.
<Para-type wholly aromatic copolyamide>
The para-type wholly aromatic copolyamide used in the present invention comprises structural repeating units represented by the following chemical structural formula (1) and the following chemical structural formula (2), and one or more kinds of divalent aromatic It is a polymer in which group groups are directly linked by amide bonds. At this time, the aromatic group is not particularly limited even if two aromatic rings are linked by oxygen, sulfur or an alkyl group. In addition, these divalent aromatic rings may be heterocyclic or the like, even if they are unsubstituted or substituted by 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. There is no particular problem even if it is bonded, and the type of the substituent and the number of the substituents are not particularly limited.

（Ａｒ^１およびＡｒ^２は独立であり、非置換あるいは置換された２価の芳香族基である。）

(Ar ¹ and Ar ² are independent and are unsubstituted or substituted divalent aromatic groups.)

（Ａｒ^１は非置換あるいは置換された２価の芳香族基である。）

(Ar ¹ is a substituted or unsubstituted divalent aromatic group)

  The para-type wholly aromatic copolyamide containing the above-mentioned structural repeating unit contained in the para-type wholly aromatic copolyamide fiber of the present invention is preferably 90% by mole or more, 95% by mole with respect to the total mass of the fiber The above content is more preferably 100% by mol.

[Composition of structural repeating unit]
The para-aromatic copolyamide used in the present invention has the structural repeating unit of the chemical structural formula (2) with respect to the sum of the structural repeating units of the chemical structural formula (1) and the chemical structural formula (2). It is preferably in the range of 30 to 90 mol%, more preferably 35 to 85 mol%, particularly preferably 40 to 80 mol%, and most preferably 50 to 80 mol%. When the content is less than 30 mol%, there is a problem that the reaction solution becomes turbid in the polymerization reaction, and when the polymerization reaction solution is used as it is as a dope (spinning solution), it is difficult to make a yarn with turbid dope It becomes.

  As a method of setting the structural repeating unit of the chemical structural formula (2) in the range of 30 to 90 mol% with respect to the total of the structural repeating units of the chemical structural formula (1) and the chemical structural formula (2) For example, among the aromatic diamines used in the polymerization of para-type wholly aromatic copolyamides described later, aromatic diamines containing the chemical structural formula (2), such as 5-amino-2- (4-aminophenylene) benzimidazole The method etc. which use 30-90 mol% with respect to the aromatic diamine whole quantity used for superposition | polymerization are mentioned.

<Method for producing para-type aromatic copolyamide>
The method for producing the para-type wholly aromatic copolyamide containing the structural repeating unit of the above-mentioned chemical structural formula (1) and the above-mentioned chemical structural formula (2) used in the present invention is not particularly limited. According to the method, it is obtained by reacting an aromatic dicarboxylic acid chloride component with an aromatic diamine component in an amide type polar solvent.

[Raw material of para-type wholly aromatic copolyamide]
[Aromatic dicarboxylic acid dichloride]
As an aromatic dicarboxylic acid dichloride used as a raw material of para-type wholly aromatic copolyamide used in the present invention, for example, terephthalic acid dichloride, 2-chloroterephthalic acid dichloride, 3-methylterephthalic acid dichloride, 4,4'-biphenyl Dicarboxylic acid dichloride, 2, 6- naphthalene dicarboxylic acid dichloride etc. are mentioned. Among these, terephthalic acid dichloride is most preferable in terms of versatility and mechanical properties of the fiber. These aromatic dicarboxylic acid dichlorides may be used alone or in combination of two or more, and the composition ratio in that case is not particularly limited.

[Aromatic diamine]
As an aromatic diamine used as a raw material of para-type wholly aromatic copolyamide used for this invention, para-phenylene diamine, 5-amino 2- (4-amino phenylene) benzimidazole, para biphenylene diamine, 3, 4 is mentioned, for example. '-Diaminodiphenyl ether, 1,4-dichloro paraphenylene diamine, etc. are mentioned. In the present invention, the present invention is not limited to these, and a substituent may be attached to the aromatic ring, or any other heterocycle may be attached thereto.

  As a raw material of the para-type wholly aromatic copolyamide used in the present invention, in order to constitute the structural repeating unit shown by the above-mentioned chemical structural formula (1) and the structural repeating unit shown by the above-mentioned chemical structural formula (2) respectively And at least two or more kinds of aromatic diamines are used. As the combination thereof, a combination of paraphenylenediamine and 5-amino-2- (4-aminophenylene) benzimidazole is most preferable in terms of versatility, mechanical properties of fibers, spinnability and the like.

  In the present invention, as described above, the structural repeating unit of the chemical structural formula (2) is 30 for the total of the structural repeating units of the chemical structural formula (1) and the chemical structural formula (2). It is preferably in the range of -90 mol%, more preferably 35 to 85 mol%, particularly preferably 40 to 80 mol%, and most preferably 50 to 80 mol%. Therefore, an aromatic diamine for constituting the chemical structural formula (2), for example, an aromatic for constituting the chemical structural formula (1), for example, 5-amino-2- (4-aminophenylene) benzimidazole. It is preferable to use so that it may become the said range with respect to the sum total of the diamine and the aromatic diamine for comprising said Chemical Structural Formula (2).

[solvent]
As an amide system polar solvent used for polymerization of para-type wholly aromatic copolyamide, for example, N-methyl-2-pyrrolidone (hereinafter referred to as NMP), N, N-dimethylacetamide, N, N-dimethylformamide, dimethylimidazo Examples include pyridinone and the like, but NMP is most preferable in view of versatility, harmfulness, handleability, solubility in para-type wholly aromatic copolyamide polymer, and the like.

[Concentrated polymer concentration]
In the polymerization reaction, in order to obtain a homogeneous high polymerization degree polymer, it is preferable to set the concentration of the produced polymer to the solvent to 10% by mass or less. In particular, in the range of 3% by mass to 8% by mass, a stable polymer can be obtained.

[Neutralization reaction]
After completion of the reaction, it is preferable to carry out the neutralization reaction by adding a basic inorganic compound such as sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide and the like, as necessary.

[Post-polymerization etc.]
The para-type wholly aromatic copolyamide polymer obtained by polymerization is a polymer solution dissolved in an amide-based polar solvent such as NMP, and can be used as it is in the spinning process without isolation. At this time, the concentration of the para-type wholly aromatic copolyamide polymer significantly affects the viscosity and stability of the polymer solution and, in turn, greatly affects the spinnability and the like in the subsequent spinning process. For this reason, it is preferable to adjust a polymer concentration to the range of 2-10 mass%. In order to adjust the polymer concentration and viscosity, an appropriate amount of an amide-based polar solvent such as NMP can be added to the obtained polymer solution.

<Production of para-type wholly aromatic copolyamide base fiber>
The para-type wholly aromatic copolyamide base fiber used in the present invention is a fiber obtained by semi-dry and semi-wet spinning. That is, a para-type wholly aromatic copolyamide solution (solution for spinning: polymer dope) containing para-type wholly aromatic copolyamide and a solvent is discharged from a spinneret to form a yarn, washed with water, dried, heat Fibers are finally obtained through steps such as drawing.

[Spinning and coagulation process]
First, a known semi-dry and semi-wet method is applied, and a spinning / coagulation process is performed in which a polymer solution is discharged from a spinneret through an air gap into a coagulating solution to coagulate.

[Pore size of spinneret]
The hole diameter of the spinneret to be used is not particularly limited, but is preferably 0.05 to 0.3 mm, more preferably 0.1 to 0.25 mm, from the viewpoint of discharge stability, spinnability, etc. Range of

[Number of holes in spinneret]
The number of holes of the spinneret is preferably 50 to 1000, and more preferably 100 to 500. When the number of holes is less than 50, the fineness of the obtained fiber is small, and another process such as a combined yarn is required to use the obtained fiber, resulting in poor productivity. On the other hand, if it exceeds 1000, uniform solidification of each single yarn becomes difficult due to an increase in the number of single yarns, and problems such as poor solidification occur to deteriorate the quality of the obtained fiber, The handling of the fiber bundle traveling also deteriorates, and it is not preferable in terms of production.

Spinning draft
The spinning draft is not particularly limited, but from 1.5 to 8 in view of adjusting the mechanical physical properties of the obtained fiber, the processability in the spinning process, and the single yarn fineness of the obtained fiber, etc. It is preferable to set it as a range.
The term "spinning draft" as used herein refers to the ratio of the take-up speed of the take-up roller disposed after the coagulation step to the linear velocity at which the polymer dope is discharged from the spinneret.

[Stretching process]
After the coagulated yarn bundle is obtained by the coagulation step, the obtained coagulated yarn bundle is subjected to a drawing step of drawing. In the stretching, for example, the fiber bundle can be plasticized in a high concentration NMP aqueous solution to be in a plasticized state.
The draw ratio in the drawing step is not particularly limited, but from the viewpoint of adjusting the mechanical physical properties of the obtained fiber, the process passability in the spinning process, and the single yarn fineness of the obtained fiber, etc. The range of 2.0 times is preferable.
Further, the drawing tension in the main drawing step is not particularly limited either, but the tension per single yarn is 10 to 25 mN / fil from the viewpoint of mechanical physical properties of the obtained fiber and process passability in the yarn manufacturing step. It is preferable to set it as a range.

[Water washing process]
Since the fiber bundle after drawing contains high concentration of NMP, water washing is performed for the purpose of removing NMP from the fiber bundle. It does not specifically limit about the water washing method of a fiber bundle, A well-known water washing method can be applied as it is. Although the amount of residual solvent in the fiber bundle after water washing is not particularly limited, it is 5000 ppm or less from the viewpoint of process passability in the drying step and heat treatment step and the influence on the hue of the finally obtained fiber. It is preferable to do.

[Drying process]
Since the fiber bundle after water washing contains much water, it is dried to remove the water from the fiber bundle. The drying method of the fiber bundle is not particularly limited, and a known drying method can be applied as it is. The temperature at the time of drying is not particularly limited as long as it is a temperature at which water can be sufficiently removed, but from the viewpoint of drying efficiency, deterioration of fibers due to drying, etc., the temperature is preferably in the range of 100 to 200 ° C. .

[Heat treatment process]
Finally, heat treatment is performed on the fiber bundle for the purpose of high orientation and high crystallization. The heat treatment method of the fiber bundle is not particularly limited, and a known heat treatment method can be applied as it is, but from the viewpoint of the influence on the hue of the finally obtained fiber and mechanical properties etc., nitrogen etc. It is preferable to carry out in the inert gas atmosphere of the above, and it is preferable to make the oxygen concentration in that case 2000 ppm or less.
The heat treatment temperature is not particularly limited, but is preferably in the range of 350 to 500 ° C. from the viewpoint of the influence on the hue of the finally obtained fiber, the mechanical properties and the like.
Further, the heat treatment tension in the heat treatment step is not particularly limited, but is in the range of 3 to 10 mN / fil from the viewpoint of process passability in the heat treatment step and mechanical properties of fibers finally obtained. Is preferred.

<Production of para-type wholly aromatic copolyamide drawn fiber>
The para-type wholly aromatic copolyamide drawn fiber of the present invention is obtained by performing high-tensile thermal drawing at a specified range of tension and temperature on the para-type wholly aromatic copolyamide raw material fiber of the above-described structure. In the present invention, a high tension thermal drawing step may be included, and other steps may be present if necessary.
The high tension heat drawing step, which is an essential step in the method for producing a para-type wholly aromatic copolyamide drawn fiber of the present invention, will be described below.

[High tension heat drawing process]
(tension)
It is essential that the tension in the high tension thermal drawing step be in the range of 1% or more and less than 20% with respect to the breaking tension of the para-type wholly aromatic copolyamide base fiber. The term "breaking tension" as used herein refers to the maximum tension at which the para-type wholly aromatic copolyamide raw material fiber before the high tension thermal drawing step completely breaks at room temperature.
When the tension is less than 1% relative to the breaking tension, the molecular orientation does not change at all because the tension is too low, and as a result, the tensile modulus is hardly improved even if high tension thermal drawing is performed. On the other hand, when the tension is 20% or more of the breaking tension, not only the quality of the single yarn constituting the fiber is broken and the quality is lowered, but the number of effective single yarns contributing to the improvement of the tensile modulus is decreased. As a result, the tensile modulus as a fiber bundle does not improve so much.

The tension in the high tension thermal drawing step is preferably in the range of 5% to 20% with respect to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber, and is in the range of 10% to 20%. Is most preferred.
As a method of setting the tension in the high tension thermal drawing step within the above range, a method of adjusting the draw ratio in the high tension thermal drawing step, etc. may be mentioned. For this reason, the draw ratio in the high tension thermal drawing process is not particularly limited as long as the tension in the high tension thermal drawing process can be made within the above range.

(temperature)
It is essential that the temperature in the high tension thermal drawing process be in the range of 50 ° C. or more and 450 ° C. or less. When the temperature is less than 50 ° C., tension also causes only mere elastic deformation, and the tension elastic modulus does not change at all since it returns to the form before stretching immediately after the tension is removed. On the other hand, if the temperature exceeds 450 ° C., not only the thermal decomposition of the para-type wholly aromatic copolyamide takes place, but it becomes a pseudo-thermoplastic state and it becomes difficult to apply high tension at drawing. And mechanical properties do not improve.
As a method of setting the temperature in the high tension thermal drawing step within the above range, a method of adjusting the ambient temperature in the high tension thermal drawing step or the surface temperature in the case of using a heating roller can be mentioned.
The temperature in the high tension thermal drawing step is preferably in the range of 100 ° C. to 425 ° C., and most preferably in the range of 150 ° C. to 400 ° C.

(Other conditions)
In the high tension thermal drawing step, other conditions such as speed and time are not particularly limited, and can be appropriately adjusted as necessary.

<Physical properties of para-type wholly aromatic copolyamide drawn fiber>
[Tensile modulus]
The para-type wholly aromatic copolyamide drawn fiber of the present invention is a fiber having a tensile modulus of 1000 cN / dtex or more. The tensile elastic modulus is preferably 1100 cN / dtex or more, and most preferably 1200 cN / dtex or more.

[Tensile strength]
The para-type wholly aromatic copolyamide fiber of the present invention preferably has a tensile strength of 30.0 cN / dtex or more. More preferably, it is 33.0 cN / dtex or more, and most preferably 35.0 cN / dtex or more.

[Single yarn fineness]
The single yarn fineness of the para-type wholly aromatic copolyamide fiber of the present invention is preferably in the range of 1 to 3 dtex. Not only fibers having a single yarn fineness of less than 1 dtex need a high draw ratio, but yarn breakage and the like at the time of process passing increase, and it becomes difficult to obtain fibers stably. On the other hand, when the single yarn fineness exceeds 3 dtex, it is not preferable because desolvation from the inside of the fiber becomes difficult in the water washing step where the single yarn fineness is large.

[Single yarn number]
The number of single yarns of the para-type wholly aromatic copolyamide fiber of the present invention is preferably in the range of 50 to 1,000. More preferably, it is in the range of 100 to 500. When the number of single yarns is less than 50, the fineness of the obtained fiber is small, and another process such as doubled yarn is required to use the fiber, resulting in poor productivity. On the other hand, when it exceeds 1000, uniform solidification for each single yarn becomes difficult in the manufacturing process due to an increase in the number of single yarns, and problems such as poor solidification occur and the quality of the fiber is lowered. There is

EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples and the like, but the present invention is not limited to these as long as the gist is not exceeded.
<Measurement and evaluation method>
In Examples and Comparative Examples, the following items were measured and evaluated by the following methods.

(1) Fineness of para-type wholly aromatic copolyamide raw material fiber The obtained fiber bundle was taken up 100 m using a known measuring machine, and the mass was measured. The mass obtained was multiplied by 100 to calculate the mass per 10000 m, that is, the fineness (dtex).

(2) Breaking tension of para-type wholly aromatic copolyamide raw material fiber Measured under the following conditions with a tension tester (trade name: INSTRON, model: 5565 type) manufactured by INSTRON, using a chuck for yarn test. did.
[Measurement condition]
Temperature: Room temperature Specimen: 75 cm
Twist factor: 0
Test speed: 250 mm / min Chuck distance: 500 mm

(3) Tension of high tension thermal drawing process The tension of the fiber passing through the high tension thermal drawing process was directly measured using a tension meter (manufactured by SCHMIDT, trade name: MECHANICAL TENSION METER, model: DN1).

(4) Tensile strength, elongation at break, tensile modulus of para-type wholly aromatic copolyamide drawn fiber Using a tension tester (trade name: INSTRON, model: 5565 type), using a yarn test chuck Based on the procedure of ASTM D885, measurements were carried out under the following conditions.
[Measurement condition]
Temperature: Room temperature Specimen: 75 cm
Twist factor: 1
Test speed: 250 mm / min Chuck distance: 500 mm

(5) Quality of para-type wholly aromatic copolyamide drawn fiber A predetermined amount of the obtained fiber is wound with a winder, and the number of single yarn breaks on the wound surface is visually counted, and the following judgment criteria It judged in.
[Evaluation criteria]
○: Number of broken single yarns = 0 to 10
Δ: Number of broken single yarns = 11 to 20
X: Number of broken single filaments> 21

Example 1
[Production of para-type wholly aromatic copolyamide]
100 parts by mass of terephthalic acid dichloride is added to 16.3 parts by mass of paraphenylenediamine dissolved in NMP and 79.0 parts by mass of 5-amino-2- (4-aminophenylene) benzimidazole by a known method. A condensation reaction was carried out to obtain a para-type wholly aromatic copolyamide polymer solution.

[Production of para-type wholly aromatic copolyamide starting fiber]
The spinneret with a pore diameter of 0.20 mm and a number of holes of 300 was heated to 105 ° C., and then the polymer solution obtained above was heated to 105 ° C. and discharged through a 10 mm air gap by a semidry and semiwet method. The coagulated yarn bundle was obtained by passing through a coagulation bath filled with an aqueous solution at 50 ° C. and an NMP concentration of 40% by mass.
Subsequently, the obtained coagulated yarn bundle was passed through a plasticizing bath filled with an aqueous solution of NMP concentration of 72% by mass and 20 ° C. to be in a plasticized state, and then plasticized and stretched. The plasticizing draw ratio was 1.45.
Subsequently, the fiber bundle after passing through the drawing process was thoroughly washed with water and dried with a drying roller at 200 ° C. to obtain a dried yarn.
Thereafter, heat treatment was performed under the conditions of 300 ppm oxygen concentration in the furnace and 460 ° C. in the furnace temperature, and was wound by a winder. The breaking tension of the obtained para-type wholly aromatic copolyamide raw material fiber was 19400 cN

[Production of para-type wholly aromatic copolyamide drawn fiber]
Next, high tension heat drawing was performed on the obtained para-type wholly aromatic copolyamide raw material fiber. The tension at this time was 2000 cN (10% with respect to the breaking tension of the para-type wholly aromatic copolyamide base fiber), and the temperature was 350 ° C.
Finally, the fiber was wound on a paper tube with a winder to obtain para-type wholly aromatic copolyamide drawn fiber. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 1.

Example 2
[Production of para-type wholly aromatic copolyamide drawn fiber]
Para-type wholly aromatic in the same manner as in Example 1 except that the tension in the high tension thermal drawing step was 1500 cN (8% relative to the breaking tension of para-type wholly aromatic copolyamide raw material fiber) and the temperature was 400 ° C. A copolyamide drawn fiber was obtained. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 1.

Example 3
[Production of para-type wholly aromatic copolyamide starting fiber]
A para-type wholly aromatic copolyamide raw material fiber was produced in the same manner as in Example 1 except that the number of holes of the spinneret in the spinning and coagulating step was changed to 155. The breaking tension of the obtained para-type wholly aromatic copolyamide base fiber was 8080 cN.

[Production of para-type wholly aromatic copolyamide drawn fiber]
A para-type wholly aromatic copolyamide drawn fiber is prepared in the same manner as in Example 1 except that the tension in the high tension thermal drawing step is 800 cN (10% relative to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber). Obtained. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 1.

Example 4
[Production of para-type wholly aromatic copolyamide starting fiber]
A para-type wholly aromatic copolyamide raw material fiber was produced in the same manner as in Example 1 except that the number of holes of the spinneret in the spinning and coagulating step was changed to 155. The breaking tension of the obtained para-type wholly aromatic copolyamide base fiber was 8080 cN.

[Production of para-type wholly aromatic copolyamide drawn fiber]
A para-type wholly aromatic copolyamide drawn fiber is prepared in the same manner as in Example 1 except that the tension in the high tension thermal drawing step is 500 cN (6% with respect to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber). Obtained. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 1.

Comparative Example 1
A para-type wholly aromatic copolyamide drawn fiber (that is, a para-type wholly aromatic copolyamide raw material fiber of Example 1) was obtained by the same method as Example 1 except that the high tension thermal drawing was not performed. Each physical property of the obtained fiber is shown in Table 2.

Comparative Example 2
A para-type wholly aromatic copolyamide drawn fiber (that is, a para-type wholly aromatic copolyamide raw material fiber of Example 3) was obtained by the same method as Example 3 except that the high tension thermal drawing was not performed. Each physical property of the obtained fiber is shown in Table 2.

Comparative Example 3
[Production of para-type wholly aromatic copolyamide drawn fiber]
Para-type wholly aromatic copolyamide drawn by the same method as in Example 1 except that the tension in the high tension thermal drawing step was 50 cN (0.6% with respect to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber) I got a fiber. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 2.

Comparative Example 4
[Production of para-type wholly aromatic copolyamide drawn fiber]
A para-type wholly aromatic copolyamide drawn fiber is prepared in the same manner as in Example 1 except that the tension in the high tension thermal drawing step is 5000 cN (26% with respect to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber). Obtained. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 2.

Comparative Example 5
[Production of para-type wholly aromatic copolyamide drawn fiber]
A para-type wholly aromatic core was obtained in the same manner as in Example 1, except that the tension in the high tension thermal drawing step was 1500 cN (8% relative to the breaking tension of the para-type wholly aromatic copolyamide raw material fiber) and the temperature 20 ° C. A polyamide stretched fiber was obtained. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 2.

Comparative Example 6
[Production of para-type wholly aromatic copolyamide drawn fiber]
A para-type wholly aromatic copolyamide drawn fiber was obtained in the same manner as in Example 1 except that the temperature in the high tension thermal drawing step was 500 ° C. Each physical property of the obtained para-type wholly aromatic copolyamide drawn fiber is shown in Table 2.

The para-type wholly aromatic copolyamide drawn fiber obtained by the method for producing the para-type wholly aromatic copolyamide drawn fiber of the present invention becomes a fiber excellent in tensile modulus. At the same time, since breakage of the single yarn constituting the fiber is suppressed, the fiber becomes high in tensile strength. Therefore, the para-type wholly aromatic copolyamide drawn fiber of the present invention is useful in various industrial material applications, and is particularly useful in reinforcing material applications such as rubber and resin and rope applications.

Claims (5)

It is a para-type wholly aromatic copolyamide drawn fiber including the structural repeating unit of the following chemical structural formula (1) and the following chemical structural formula (2) , and the tensile modulus of the para-type wholly aromatic copolyamide drawn fiber is A method for producing a para-type wholly aromatic copolyamide drawn fiber having a density of 1000 cN / dtex or more ,
Para-type wholly aromatic copolyamide base fiber obtained by wet spinning or semi-dry and semi-wet spinning of para-type wholly aromatic copolyamide solution is 1% or more with respect to breaking tension of para-type wholly aromatic copolyamide base fiber A method for producing a para-type wholly aromatic copolyamide drawn fiber, comprising a high tension thermal drawing step of thermally drawing at a temperature of 50 ° C to 450 ° C under a tension of less than 20% .

(Ar ¹ and Ar ² are independent and are unsubstituted or substituted divalent aromatic groups.)

(Ar ¹ is a substituted or unsubstituted divalent aromatic group) The method for producing a para-type wholly aromatic copolyamide drawn fiber according to claim 1, wherein the tensile strength of the para-type wholly aromatic copolyamide drawn fiber is 30.0 cN / dtex or more. The para-type wholly aromatic copolyamide, relative to the total amount of the structural repeat units of the chemical formulas (1) and the chemical formula (2), structural repeat unit of the chemical formula (2) 30 to 90 The method for producing para-type wholly aromatic copolyamide drawn fiber according to claim 1 or 2 which is mol%. The method for producing a para-type wholly aromatic copolyamide drawn fiber according to any one of claims 1 to 3, wherein a single yarn fineness of the para-type wholly aromatic copolyamide drawn fiber is 1 to 3 dtex. The method for producing a para-type wholly aromatic copolyamide drawn fiber according to any one of claims 1 to 4, wherein the number of single yarns of the para-type wholly aromatic copolyamide drawn fiber is 50 to 1000.