JPS6094617A - Production of poly-p-phenylene terephthalamide fiber - Google Patents

Abstract

PURPOSE:To manufacture a poly-p-pheynylene terephthalamide (PPTA) fiber having strength and elongation in high efficiency, by providing a thin tube or small nozzle at the bottom of a coagulation bath, accelerating the flow of the coagulation liquid extruded from the tube, etc. and falling in a space, and decelerating the coagulation liquid accompanying to the coagulated filament. CONSTITUTION:A concentrated sulfuric acid solution of a PPTA polymer is passed through a noncoagulating fluid layer, introduced into a coagulation bath, and extruded in the form of a filament together with the flow of coagulation liquid through the thin tube or small nozzle attached to the bottom of the coagulation bath. The filament is passed through the second thin tube or small nozzle, and then subjected to the finishing treatments such as washing, drying, etc. The coagulation bath liquid is pressurized via the noncoagulating fluid layer, and the pressure of the space between the liquid and the second thin tube or small nozzle is decreased to accelerate the flow of the coagulation liquid at the thin tube or the small nozzle of the bottom part of the coagulation bath and to decelerate the flow in the second thin tube or small nozzle under the first tube, etc. A PPTA fiber having excellent mechanical properties can be manufactured at an industrially advantageous rate of spinning, i.e. >=600m/min.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing polyhalaphenylene terephthalamide (hereinafter abbreviated as rPPTAJ) fiber. More specifically, PPTA with improved mechanical properties
The present invention relates to a high-speed spinning method for efficiently producing fibers at an industrially advantageous speed.

Prior Art It is known that fully aromatic polyamides can be derived from aromatic diamines, aromatic dicarboxylic acids, and/or aromatic aminocarboxylic acids, and it is also already known that fibers can be obtained from these aromatic polyamides. . Furthermore, among such aromatic boria-based polymers, especially PPTA-based polymers, as expected from their rigid molecular structure, have a high melting point,
It is also already known that fibers having favorable physical properties such as excellent crystallinity, high strength, and high Young's modulus can be obtained.

For example, according to Japanese Patent Application Laid-Open No. 47-39458, a solution exhibiting optical anisotropy of a PPTA-based polymer dissolved in concentrated sulfuric acid with a concentration of at least 98% is passed through an orifice to form an inert, non-coagulable polymer. It is disclosed that fibers with favorable mechanical properties are obtained by extrusion into a fluid and then through a coagulation bath. However, in this method, a large take-up tension, ie, spinning tension, is applied to the yarn due to the frictional resistance between the coagulating liquid in the coagulation bath and the traveling yarn. Since this spinning tension increases with increasing spinning speed, a low spinning tension, i.e., at a low spinning speed, gives a fiber with excellent mechanical properties, but as the spinning speed increases, the resulting fiber strength decreases. Both elongations are significantly reduced. Therefore, at an industrially meaningful spinning speed,
It has been difficult to obtain PPTA fibers with excellent mechanical properties.

In contrast to such methods, in order to reduce the spinning tension, which tends to increase significantly as the spinning speed increases, a specific spin tube (pore) is provided at the bottom of the coagulation bath to allow the yarn and coagulation liquid to fall simultaneously. Method of spinning (Japanese Unexamined Patent Publication No. 53-78
320) was proposed, but at high spinning speeds, especially aoo
At a spinning speed of m/min or more, the tension cannot be sufficiently reduced and high fiber performance cannot be obtained.

Furthermore, in order to reduce the frictional resistance caused by the speed difference between the coagulating liquid and the yarn in the high spinning speed range, a method of pressurizing the coagulating bath liquid and accelerating the speed of the coagulating liquid from the spin tube (% open rFF
15B-78321), or a method in which a separate coagulating liquid jetted from a plurality of small-diameter nozzles or slits is applied to the yarn and coagulating liquid stream falling through a spin tube in the direction in which the yarn is taken off to accelerate the coagulating liquid. (Unexamined Japanese Patent Publication No. 56-tzs
siz publication) was proposed. However, although it is possible to reduce the apparent overspinning tension by accelerating the coagulation liquid speed, especially in the latter method, the coagulation liquid jetted by ejection may cause locally excessive tension. As a result, the higher-order structure of the yarn is destroyed due to incomplete coagulation, resulting in a decrease in strength and elongation, making it impossible to obtain a fiber with sufficiently high performance.

On the other hand, as a method to reduce the spinning tension, the spin tube is installed at a very shallow position in the coagulation bath to reduce the amount of coagulated liquid that falls with the yarn, and if necessary, the yarn and coagulated liquid that fall through the spin tube are A method in which a specific amount of another coagulating liquid is applied as a jet stream in the yarn take-off direction to accelerate the process (%
Japanese Patent Publication No. 57-121612) was proposed. However, in this method, since the coagulation bath is shallow and the amount of coagulation liquid falling is reduced, coagulation is more incomplete, and even if the tension is reduced, the crystal orientation in the yarn and the yarn As a result of the parallel destruction of the higher-order structure of the striations,
Even in the case where fibers have low strength and elongation, or even if the decrease in strength can be suppressed to a small extent by the effect of reducing tension, the result is only fibers with low elongation. Naturally, this tendency becomes more pronounced in the high spinning speed range because the inertial force increases as the spinning speed increases.

Furthermore, when a sulfuric acid aqueous solution, which is under extremely advantageous conditions industrially, is used as a coagulation liquid, the progress of coagulation is delayed and becomes even more pronounced, resulting in high-performance PPT that can be put to practical use.
A fiber cannot be obtained.

It is well known that in terms of practical performance of PPTA fibers, it is important not only to have high strength but also high elongation, and especially for fibers used as tire cords, it is important to have high elongation. extremely important.

Problems to be Solved by the Invention In view of the above points, the present inventor has devised a method for efficiently producing PPTA fibers having excellent fiber performance, including not only high strength but also high elongation, at an industrially advantageous speed. Regarding the method of
Formation of threads in the coagulation process from a concentrated sulfuric acid solution of PPTA-based polymer (hereinafter simply referred to as "dope"),
We have continued to conduct long-term research while adjusting the physical properties and structure of the resulting PPTA fibers. As a result, in the wet spinning method in which the dope is introduced into a coagulation bath through a non-coagulable fluid layer, the spinning tension applied for yarn formation and the coagulation state expressed as an index of deoxidation of sulfuric acid, which is a solvent, are It has been discovered that PPTA fibers with high strength, high elongation, and excellent mechanical properties can be obtained only when certain specific conditions are met. Based on this knowledge, as a result of further intensive studies, we finally decided to provide a thin tube or pore at the bottom of the coagulation bath to accelerate the falling coagulating liquid even at high spinning speeds of 600 m/min or more. to run through space,
Next, it was discovered that high strength and high elongation PPTA fibers could be obtained by slowing down the coagulation deceleration accompanying thread growth, leading to the completion of the present invention. The purpose of the present invention is to improve strength and elongation. The object of the present invention is to provide a method for efficiently producing high-performance PPTA fibers at industrially advantageous high spinning speeds.

Structure of the Invention The method for producing PPTA fibers according to the present invention is a wet spinning method in which a solution exhibiting optical anisotropy of a PPTA polymer is passed through a non-coagulating fluid layer and then introduced into a coagulating bath. The thread is drawn out along with the flow of coagulating liquid from a capillary or pore provided at the bottom, and then the thread is passed through a second capillary or pore installed with a space below the capillary or pore. After running, the yarn is subjected to finishing processes such as washing and drying by installing a thin tube or pore at the bottom of the coagulation bath at the upper and lower ends of a sealed chamber, By pressurizing the coagulation bath liquid through the fluid layer and reducing the pressure in the closed chamber, the flow of the coagulation liquid in the lower tubes or pores of the coagulation bath is accelerated, and the flow of the coagulation liquid in the lower second tube or pore is accelerated. It is characterized by reducing the flow velocity at .

Preferred Embodiments In the method of the present invention, the PPTA-based polymer is a copolyand in which 10 moles or less of seven units in the poly-paraphenylene terephthalate structure consist of other aromatic diamino residues or/and other aromatic dicarboxylic groups, respectively. ◎These PPTA-based polymers can be used in the method of the present invention either singly or as a mixture.

In the method for producing PPTA-based fibers according to the present invention, high-performance fibers having at least a strength of X111f/d or more, an elongation of 3- or more, and an initial modulus of 25O1711 or more should be targeted. For this purpose, the degree of polymerization of the PPTA-based polymer used must be at least a certain value, and should be at least 3.5 or more, especially 4.5 or more in terms of intrinsic viscosity (η1nh). desirable.

The spinning dope used in the method of the present invention, including the PPTA-based polymer d, is prepared by a known method. In this case, concentrated sulfuric acid is industrially advantageously used as the solvent. The concentration of concentrated sulfuric acid is preferably 95% by weight or more, and when dissolving a PPTA polymer having a particularly high intrinsic viscosity at a high concentration, 97.5% by weight or more, more preferably 99% by weight or more is used. .

Polymer #Iif of the spinning dope needs to be concentrated, as it is generally easier to obtain high-performance fibers when it is high, and it should preferably be at least 13% by weight or more, more preferably 15% by weight or more. . However, if the quality is too high, for example, 22 folds or more, the viscosity of the dope becomes too high, so it is necessary to set the dope temperature high, which tends to cause difficulties in the spinning operation. Therefore, it should not be chosen too high. When preparing and using the dope, in the above polymer concentration range, the dope may solidify near room temperature.
It can be handled at temperatures around ℃. However, from the viewpoint of avoiding decomposition of the polymer as much as possible, a temperature as low as possible should be selected as long as it does not solidify.

It is recognized that the spinning dope prepared in this way has optical anisotropy within the above polymer concentration and doping temperature ranges. Such dopes are used in the process of the present invention, once forced through a spinneret into a non-coagulating fluid layer, usually air, and then introduced into a coagulation bath. At this time, since the coagulating or coagulated yarn in the coagulation bath is hardly stretched, the discharged dope is placed in the draft of the take-up (
Stretching) is stretched out.

In this stretching, if the stretching rate is low, the physical properties of the fiber cannot be sufficiently enhanced, and if the stretching rate is too high, the dope flow will be cut off in this stretch, so the stretching rate is usually 4 to 15 times, preferably 5 times. It is set between ~12 times.

The length of the non-coagulable fluid layer in which the dope is stretched, usually in air, that is, the distance from the surface of the spinning nozzle where the dope is discharged to the surface of the coagulating bath liquid, is usually about 1 to 50 layers.
The distance is preferably set in a range of 3 to 20 m, but is not limited to this.

Specifically, it should be determined in consideration of the dope discharge rate from the spinning nozzle, the above-mentioned draft rate, reducing the chance of filament fusion, etc.

In addition, the hole diameter of the spinning nozzle used for discharging the dope should be selected depending on the thickness of the fiber to be manufactured and the above-mentioned draft rate setting, and is usually 0.
The number of holes provided in the spinning nozzle should be determined depending on the composition of the fiber to be produced. However, there are no particular limitations when implementing the method of the present invention.

In carrying out the invention, water or an aqueous sulfuric acid solution having a concentration of up to 70% is advantageously used as the coagulating liquid. However, for example, aqueous solutions of salts such as ammonium chloride, calcium chloride, calcium carbonate, sodium chloride, sodium sulfate, etc., or mixtures thereof, aqueous ammonia bath solutions, aqueous sodium hydroxide solutions, or methanol, ethanol, ethylene glycol, etc. It may be an organic solvent such as or an aqueous solution thereof, and is not particularly limited.

The temperature of the coagulating liquid is generally kept at 15°C or lower, more preferably at 10°C or lower.

In the method of the present invention for producing high-performance PPTA fibers at industrially advantageous high spinning speeds, the dope discharged and stretched as described above is introduced into a coagulation bath,
While forming a thread, the thread is drawn out along with the coagulating liquid flow from a capillary or pore provided at the bottom of the coagulation bath, and then a second capillary or capillary is installed below the capillary or pore via a space. The thread is made to travel through the hole, and the speed of the coagulating liquid falling together with the thread is accelerated in the capillary or pore provided at the bottom of the coagulation bath. In the process of forming 0PPTA fibers, the main feature is that the speed of the accompanying coagulating liquid is slowed down in the second capillary or pore installed through the space/interval. Fibers are formed while undergoing changes such as destruction of structure and progression of orientation, but these are not simply a function of tension;
It should be understood that the tension varies greatly depending on the coagulation state of the yarn to which it is applied.

When producing PPTA-based fibers at high spinning speeds, an increase in spinning speed, an increase in spinning tension, and a delay in coagulation due to a decrease in contact time with the coagulation liquid occur simultaneously, resulting in incomplete coagulation. Since high tension is applied to the uncoagulated filament, a capillary or pore is simply provided at the bottom of the coagulation bath.
In the method of accelerating the coagulated liquid together with the yarn by the acceleration of gravity, or in the method of forcibly accelerating the speed of the coagulated liquid by, for example, a downward jet flow, the apparent spinning tension measured at the time of top take-up. Although the flow of the coagulating liquid is reduced, sufficient tension is applied to the incompletely coagulated filament to cause structural destruction or sufficient tension to promote orientation. It has not been possible to obtain a PPTA fiber having both sufficiently high strength and elongation.

Therefore, in order to produce high-performance PPTA fibers with excellent strength and elongation at high spinning speeds, it is necessary to prevent destruction of the fiber structure even in uncoagulated yarns with a low degree of coagulation. Furthermore, it is necessary to reduce the tension depending on the solidification state so as to suppress the progress of orientation that causes a decrease in elongation. To do this, the flow rate of the coagulating liquid accompanying the yarn is accelerated to reduce the frictional resistance between the yarn and the coagulating liquid, and once the accelerated -fc coagulating liquid flow rate is made to travel through the space, By slowing down the coagulation fluid flow rate,
During this time, coagulation can proceed and fibers can be formed while maintaining the tension applied to the yarn in an extremely low state. Here,
It must be understood that the provision of a second capillary or pore to reduce the flow rate of the coagulating liquid is of great significance in the method of the present invention.

As mentioned above, high-performance PPTA with excellent strength and elongation.
In order to produce fibers, the spinning tension should be reduced depending on the coagulation state of the yarn. In particular, by adopting a spinning speed of 600 m/min or more, we can produce PP with excellent strength and elongation.
In order to produce TA fibers, the speed of the coagulating liquid falling together with the threads is accelerated in the thin tubes or pores provided at the bottom of the coagulation bath, and a space is provided below the thin tubes or pores. By slowing down the velocity of the accompanying coagulating liquid in the second capillary or pore, the flow of the coagulating liquid can be measured at a separated position after the yarn passes through the second capillary or pore. The coagulation state index (Ws/Wp) representing the take-up tension (T) and the deoxidation rate of the solvent sulfuric acid (Ws/Wp) is calculated by the following formula (
It is important to satisfy 1).

1.425≦T OJO・(Ws/Wp)−′・11
(1) [In formula (1), T is the yarn take-up tension (
r/d ), Ws/Wp represents the ratio of the weight of polymer in the yarn (Wp) taken out from the second capillary or pore to the weight of pure sulfuric acid in the yarn (W8). ] That is, the more the uncoagulated yarn is delayed in completion of coagulation, the lower the tension applied at that time needs to be. On the other hand, if the yarn has a high degree of coagulation, destruction of the higher-order structure will be suppressed even under relatively high tension.

In the method of the present invention, if the value calculated by the tension and Ws/Wp does not satisfy the above formula (1), the connection between the thin tube or pore provided at the bottom of the coagulation bath and the second thin tube or pore is determined. During this period, the tension or Ws/Wp becomes high enough to cause destruction of the higher-order structure of the yarn and/or promotion of orientation, resulting in a PPTA-based fiber with improved high strength and elongation. This can easily become difficult.

In the method of the present invention, in which the coagulating liquid is accelerated in a capillary or pore provided at the bottom of the coagulation bath and decelerated in a second capillary or pore, the spinning tension and the Ws/Wp value are adjusted according to the speed of the coagulating liquid to be accelerated or decelerated. The flow rate varies depending on the flow rate, the spinning speed set, the type of coagulation liquid used, etc. Therefore, when carrying out the method of the present invention at a high spinning speed, particularly at a high spinning speed of 1 minute or more, it is preferable to
These factor conditions should be determined so as to satisfy the above formula (1), and in doing so, it is important to pay attention to the following points regarding each factor condition.

The flow rate of the coagulating liquid should be at least sufficient to form yarn from the dope at the set spinning speed, but if it becomes too large, the flow rate may be reduced in the second capillary or pore. This is not preferable because it causes locally excessive tension to be generated during deceleration. Usually, the mass is set to approximately 50 to 500 times the mass per unit time of the PPTA polymer forming the thread.

The flow rate of the coagulating liquid accelerated in the capillaries or pores provided at the bottom of the coagulating bath is an important condition factor for reducing the spinning tension. In order to reduce the spinning tension, the speed difference with the yarn traveling at the set spinning speed should be made as small as possible. On the other hand, in order to promote coagulation and further improve the degree of coagulation, it is necessary to create a difference between the coagulation liquid speed and the thread running speed.
The flow rate of the coagulating liquid to be accelerated should be determined taking into account the advantage of promoting diffusion of the solvent. According to the results of detailed study by the present inventors based on these findings, the flow rate of the coagulating liquid to be accelerated is
That is, about 0.5 to 2.0 times the spinning speed, especially 0.7 to 1.
It is preferable to increase the amount by 5 times. If it is less than 0.5 times, the effect of sufficiently reducing the spinning tension is poor, and if it is more than 2.0 times, tension is locally and rapidly applied to the yarn in the tubules or pores, resulting in high-order This may lead to destruction of the structure and, on the contrary, tend to cause a decline in fiber performance.

On the other hand, the flow rate of the coagulating liquid in the second capillary or pore is decelerated by a method that will be specifically explained later, and the degree of deceleration is determined by measuring the diameter of the thread passing through the second capillary or pore. should be determined by the spinning tension and Ws/Wp value. That is, at high spinning speeds of 600 m/min or higher, due to the slowdown of the coagulation deceleration in the second capillary or pore, the spinning tension can be reduced at each set spinning speed without any coagulation deceleration without the provision of the second capillary or pore. The spinning tension can be approximately 0.3 to 0.8 times the spinning tension when the speed is not reduced.

Therefore, depending on the set spinning speed, the spinning tension and W
The s/Wp value may be arbitrarily set so as to satisfy the above formula (1).

In the method of the present invention, in order to accelerate the coagulation deceleration in the capillary or pore provided at the bottom of the coagulation bath and to slow down the coagulation deceleration in the second capillary or pore, the capillary or pore provided at the bottom of the coagulation bath, Lower second capillaries or pores are installed at the upper and lower ends of a single sealed chamber, respectively, to pressurize the coagulation bath liquid through a non-coagulable fluid layer and reduce the pressure inside the sealed chamber. This is done by making At this time, while satisfying the above formula (1), 60
In order to obtain high-performance PPTA fibers at a high spinning speed of 01 rL/min or more, it is necessary that the differential pressure Δp between the pressurized fluid layer and the inside of the closed room satisfies the following formula (2). .

0.74X1G-6・V”≦△p≦3.40X10-6
・V'' (2) [In formula (2), Δp is the differential pressure (Ky/
cd ), ■ represents the spinning speed (m/min).

When the differential pressure Δp is outside the range of formula Q), the speed difference between the speed of coagulation deceleration in the thin tube or pore provided at the bottom of the coagulation bath and the taken-up yarn becomes large, causing excessive frictional resistance in extremely localized areas. This is because, as a result, both the strength and elongation properties of the resulting fibers are reduced.

In addition, in a closed room, there is a space between the thin tube or pore provided at the bottom of the coagulation bath and the second thin tube or pore, except for the thread and the coagulating liquid that falls along with the thread. Should be. That is, for example, if this gap is entirely filled with a coagulating liquid, or if a part of the upper part of the second capillary or pore is filled with the coagulating liquid, excessive frictional resistance with the coagulating liquid may occur in this part. This means that the spinning tension cannot be reduced. Therefore, the second
It is not preferable that any coagulating liquid other than the filament and the coagulating liquid flow that falls together with the filament remain in the upper part of the capillary or pore. To this end, the coagulated liquid that is slowed down and retained in the second capillary or pore should be actively removed from the traveling area of the thread and the flow of coagulated liquid that falls along with the thread.

For example, the apparatus shown in FIG. 1 is particularly preferred for use in the method of the present invention. In this device, a capillary tube or pore section υ provided at the bottom of the coagulation bath and a second capillary tube or pore section (I3) are installed in the upper and lower ends of the integrated sealed chamber (II). By suctioning from the outside of this sealed room a0 through the vacuum evacuation nozzle α, the flow rate of the coagulating liquid is reduced in the second capillary or pore α, and the excess is removed at the upper part of the second capillary or pore. It is possible to scatter and eliminate the coagulating liquid.

In such a method, the degree of acceleration and deceleration of coagulation deceleration should be adjustable as a condition factor to satisfy the above-mentioned equations (1) and (2).

For example, in the above example, it is possible to adjust the pressure applied to the surface of the coagulation bath and the degree of vacuum in the sealed room.

The lower part of the coagulation bath and the second part used in carrying out the method of the present invention
The tubules or pores are not particularly limited and have the formula (
It should be determined based on requirements such as the mass and flow rate of the coagulating liquid that falls with the yarn, which are set so as to satisfy 1) and (2). The main requirement here is the diameter of the capillaries or pores. The diameter of the capillary or pore varies depending on the composition of the fiber to be manufactured, the spinning speed, etc., but depending on the mass of the coagulating liquid and the flow rate requirements, the diameter of the capillary or pore is 5 to 15% of the cross-sectional area of the thread passing through the capillary or pore.
It should be set so that it has a cross-sectional area of 0 times, and usually a range is selected that gives a cross-sectional area of 10 to 120 times. Further, the cross-sectional shape of the capillary or pore is usually circular, but is not particularly limited in the method of the present invention, and may be, for example, rectangular, triangular, or elliptical. The length of the capillary or pore is not particularly limited in the method of the present invention, and for example, the capillary may have a length to diameter ratio of 200 or more. However, extremely long tubes are not preferred because the resistance between the tube wall and the coagulating liquid increases, making acceleration or deceleration operations difficult. Therefore, the above ratio is usually between 0.2 and 5.
Tubules or pores in the range 0 are advantageously used.

In the method of the present invention, for example, those shown in Figures 2 (A), (B), (Q and (6)) can be used as such thin tubes or pores. It is also possible to use a series of individual thin tubes or pores.Furthermore, in order to facilitate the introduction and penetration of the thread as necessary, a tapered introduction part may be provided at the upper and/or lower part of the thread. Alternatively, in order to facilitate the convection of the coagulating liquid in the coagulation bath and its flow into the thin tubes or pores, it is also possible to install a current plate or the like at the top of the thin tubes or pores provided at the bottom of the coagulation bath. The provision of these is optional as long as it does not impair the purpose of the method of the present invention.

In carrying out the method of the present invention, the above-mentioned thin tubes or pores are installed in two places, one at the bottom of the coagulation bath and a space below the coagulation bath. ,
The depth should be set to within 20° from the surface of the coagulation bath. That is, the dope discharged from the spinning nozzle is introduced into a coagulation bath through a non-coagulable fluid layer, and at the same time coagulation begins while being subjected to spinning tension. In the coagulation bath, the yarn runs at a set spinning speed, accelerating the coagulation liquid at the same time, but since the coagulation speed of the coagulation liquid is slow compared to the speed of the yarn, it creates resistance and is being coagulated. This is because there is a risk of destroying the higher-order structure of the yarn. Therefore,
In order to suppress the destruction of the higher-order structure of the yarn in the coagulation bath, it is preferable to pass the thread through a capillary or pore at an early stage and proceed with coagulation using an accelerated coagulation liquid. According to the studies conducted by the present inventors from these viewpoints, the number of thin tubes or pores installed at the bottom of the coagulation bath varies depending on the type and concentration of the coagulation liquid, but it has been found that
It should be installed at a depth of 10 to 1501 B from the surface of the coagulation bath, particularly preferably IO=
It is installed within a range of 100ms.

In contrast to the thin tubes or pores in the lower part of the coagulation bath installed in this way, the second thin tubes or pores are inserted through the space necessary for sufficiently proceeding coagulation in a state of extremely low tension. It should be installed at a position of 100 to 2000 m from the outlet of the capillary or pore at the bottom of the coagulation bath, particularly at a position of 25G-6000.

The yarn coagulated by the method of the present invention is pulled out from the second capillary or pore by a pulling means such as a Nelson roll at an extremely high speed of 7 minutes or more, and the attached coagulating liquid or the remaining solvent sulfuric acid is removed. neutralization,
It is used for finishing processes such as washing and drying. At that time, the neutralization, washing, or washing of the salts generated by the neutralization of the acid contained in the formed yarn fibers is performed on the PPTA finally obtained.
In view of the quality of the fibers, these treatments must be carried out particularly thoroughly, and these treatments require a long time. As a method for carrying out such thorough neutralization or cleaning over a long period of time, it is possible to use a method in which a large number of rolls are combined to increase the residence time, but in particular, the method described in Japanese Patent Publication No. 55-9088 is suitable. A method in which PPTA fibers are deposited on a net conveyor, washed with water, neutralized, and dried is preferably used both industrially and from the viewpoint of obtaining high-quality fibers. Furthermore, in carrying out the method of the present invention, it is also permissible to carry out further heat treatment after drying on a net conveyor as proposed in Japanese Patent Publication No. 54-36698.

The method of the present invention is effective for the production of all PPTA fibers, but due to the high crystallinity of PPTAPPA fibers,
It is desirable that the thickness of the single fibers is not too thick, since the fibers tend to fibrillate b1 and crack easily.

The normal line is set to approximately 10 denier or less, preferably 3 denier or less.

The linear density of the wire fiber is 20 to 4500 deniers, usually 50
Effects of the Invention In the production of PPTA-based fibers by the method of the present invention, the physical properties of the fibers in the conventional high-speed spinning method for PPTA-based fibers are improved, especially at high spinning speeds of 600 m7 min or more. ,
In addition to an improvement in strength of 5 to 20 or more, especially in elongation of about 1
All PPTs can achieve an improvement of 5-30% or more
This can be achieved for the production of A-based fibers. The excellent effects of the method of the present invention are even more remarkable when an aqueous sulfuric acid solution of 70 or less, preferably 20 to 40, is used as the coagulating liquid, and is extremely advantageous industrially.

PPT thus obtained by implementing the method of the present invention
A-series fibers are fibers that are excellent in both strength and elongation, and these excellent properties are very advantageous in terms of consumption performance when the fibers are actually used.

Due to its excellent properties, the PPTA-based fiber obtained by the method of the present invention is used for both clothing and industrial materials, but in particular for braided hoses, conveyor belts, tires, etc.
It is particularly useful in fields where the characteristics of high strength and high elongation are fully utilized, such as rubber reinforcement materials such as air bags and reinforced fiber materials for plastics.

Examples Hereinafter, the present invention will be explained in more detail with reference to Examples.
These examples do not limit the invention in any way.

In the examples, unless otherwise specified, "part" and "part" represent weight percent and part by weight, respectively. Further, the main various parameters used in the method of the present invention were measured as follows.

Measuring method of intrinsic viscosity〉 Intrinsic viscosity (η1nh) is 98.51j: it'A
(7) Concentration of concentrated sulfuric acid (C'l = 0.5 v/d
At t, a solution in which the polymer or fibers are dissolved is measured at 30°C by a conventional method.

<Method for measuring the strength and elongation properties of fibers> The strength, elongation, and Young's modulus of fiber yarns were measured in accordance with the J Engineering S standard. Using a constant speed extension type strength and elongation tester,
A load-elongation rate curve was drawn at a gripping length of 20 cm and a pulling speed of 50%/min, and the curve was read or calculated, and is expressed as the average value of 20 measurements.

Measuring method of Ws/Wp ratio of coagulated thread> The coagulated thread pulled out from the second capillary or pore is rolled up on a roll for a certain period of time, and the fibers are made into a skein using a centrifuge. After dehydrating for 1 minute under 600Orom, 0
．． Neutralization titration is performed with 1N NaOH to measure the acid form amount NVa. After the titration, the fibers are washed with water and dried, and then the weight Wp is measured, and the ratio Ws/Wp is determined.

<Measurement method of spinning tension (take-up tension)> The coagulated yarn pulled out from the second capillary or pore is changed direction by a direction change guide and taken up onto a roll, and at this time, the direction change guide is constantly moved between the direction change guide and the take-up roll. The tension value (
It is calculated as the tension per dry fiber denier (f/d), which is calculated by dividing the fiber by the denier after washing and drying the yarn, and is expressed as the average value of five measurements.

Methods for Measuring Fatigue Resistance of Fibers Various methods have been proposed for evaluating the fatigue resistance of reinforcing fibers when used in rubber products such as tires.
In the present invention, Japanese Industrial Standard GIS-1017-1963
Reference section 1 of “Chemical fiber tire cord test method”
．． Adopting the tube fatigue strength method A (Gutdeyer method) described in Section 3.2.1, a tube-shaped test piece in which a cord (treated cord) bonded between the sample fiber and rubber was embedded parallel to the axis was According to the above JIS reference, it is bent to on') and attached to an elongation-compression fatigue testing machine. Next, an internal pressure of 3.5~/cdG was applied to the test piece using air.
The tube was rotated at a speed of 0 times/min, the fatigue life of the tube was measured, and the fatigue resistance of the fibers of the present invention and comparative fibers were compared. Note that the average value of three test pieces is used as the value of tube fatigue life.

The fatigue resistance of a fiber cord varies greatly depending on the number of twists of the cord, and it is known that the fatigue resistance is generally better as the number of twists increases up to a certain range. On the other hand, for fibers with low elongation, increasing the number of twists in the cord results in a decrease in the ratio of cord strength to raw filament strength (strength utilization ratio), so it is effective to utilize the high strength of the preferred raw filament. Therefore, it is not a good idea to increase the number of twists to improve fatigue resistance. From this point of view, the preferable characteristics of the fibers of the present invention are utilized, but caution should be taken when evaluating fatigue resistance in the present invention. In the present invention, the above test is conducted with the cord twisting structure constant, the twisting structure being double yarn, and the twist coefficient (twist multiplier) being constant at 8.0.

Here, the twist coefficient is (number of twists/m)%1-505'-'--#)/28
It is made to wear clothes at 70.

The manufacturing method of the treated cord to be subjected to the fatigue test is carried out under the same conditions as below, but of course these are not the only conditions for demonstrating the characteristics of the fibers of the present invention. It may be changed in actual use.

The cord is manufactured by first twisting and final twisting and then combining and twisting to obtain the above-mentioned twist coefficient. The treated cord was coated with epoxy resin and treated under a tension of 124 at 250°C, then resorcinol-formalin-latex (RFL) was applied and a second stage treatment was carried out at 230°C under a tension of 8t/C1. Create by doing.

The epoxy resin treatment liquid used here is a dispersion consisting of 3 parts ethanol, 5 parts polyvinylpyridine latex, 25 parts water, and 67 parts of Ebicor 812 (trade name, Shell Chemical Co., Ltd.), and the RFL treatment liquid is a dispersion liquid consisting of 67 parts of resorcinol.
It consists of 11 parts water, 238.4 parts, 87 thiformin, 16.2 parts, and 0.3 parts of NaOH, and after adjustment, it is left to stand day and night.

The processing cord is embedded in unvulcanized rubber and vulcanized.

The composition of the compounded rubber used is as follows, and the vulcanization conditions are 1.
40 minutes at 40°C.

Natural rubber 90 parts Styrene-butadiene copolymer rubber 10s Carbon black 40 parts Stearic acid 2 parts Petroleum softener 10 parts Pine tar 4 parts Lead Flower 5 parts N-phenyl-β-naphthylamine 1.5 parts 2-benzothiazoli Ludisulfide 0.75 parts Diphenylguanidine 0.75 parts Sulfur 2.5 parts Reference Example The following PPTA polymer was obtained by a low temperature solution polymerization method.

In the polymerization apparatus shown in Japanese Patent Publication No. 53-43986, 70 parts of anhydrous calcium chloride was dissolved in 1000 parts of N-methylpyrrolidone, and then 48.
After cooling to 08° C., 91.4 parts of terephthalic acid dichloride was added at once in powder form. After a few minutes, the polymerization reaction product solidified into a cheese-like shape, so it was
The polymerization reaction product was discharged from the polymerization apparatus according to the method described in Japanese Patent No. 8986, and immediately transferred to a twin-screw closed kneader, and the polymerization reaction product was pulverized in the same kneader. Next, transfer the finely ground material into a Henschel mixer and use the Habo 4! After further pulverization by adding water from the ground, it was filtered, washed several times in hot water, and dried in hot air at 110°C. 95 parts of pale yellow PPTA polymer with an intrinsic viscosity of 6.2 was obtained.

Note that polymers with different intrinsic viscosities can be easily obtained by changing the ratio of N-methylpyrrolidone and monomers (para-phenylenediamine and terephthalic acid dichloride), and/or the ratio between monomers.

Example 1 98.5% sulfuric acid 30°C, 0.5 t/Zoo (ic
Poly-paraphenylene terephthalamide with an intrinsic viscosity (η1nh) of 7.05, determined by six rivers, was added to 99.7% concentrated sulfuric acid so that the polymer concentration was 18.71, and the temperature was maintained at 80°C. A polymer solution for spinning (hereinafter abbreviated as dope) was prepared. It was confirmed by polarizing microscopy observation under crossed Nicols that this polymer solution exhibited optical anisotropy.

This dope was left to stand under vacuum for 2 hours to defoam, and then used for spinning.

After passing the dope through a gear pump and filtering it through a candle filter made of eight layers of 300-mesh stainless steel wire mesh, the dope was passed through a 0.
It was extruded into a coagulation bath through a spinning nozzle having a hole diameter of m5φ and 100 holes through which 5 u of air was passed. The coagulation liquid is 1
A 10-thiosulfuric acid water bath solution cooled to 5°C was used. Next, the threads equalized in the coagulation bath are passed through the lower part of the coagulation bath and the second pore to change direction with a change-of-direction roll, then taken up with a Nelson roll, then wound onto a grain bobbin with a winder, and this bobbin is placed in running water. After washing the yarn by soaking it overnight in
It was dried in a hot air dryer at 10°C.

The apparatus used for spinning at this time is shown in Fig. 1, and is a coagulation bath (diameter Zo
oms depth of 100 m) and a sealed pressure chamber (24) for pressurizing the coagulation bath liquid.

The pressurization chamber has a nozzle (25
) is attached. The coagulation bath having a closed chamber has an inner diameter of 21 Jl and has a structure shown in FIG. 2-(6) at a depth of 40 wJ from the light surface of the coagulation bath liquid.

A pore aυ with a length of 3u, and a pore 43011JI below the pore with a second pore having the structure shown in FIG. Nozzle α
In fact, a drainage nozzle α is attached.

During spinning, pressurized air is introduced through the pressure nozzle (24), and exhausted by a vacuum pump from the depressurizing air nozzle a3, and the machine is adjusted to achieve each set pressure. From the liquid nozzle Q4), the coagulation liquid staying at the bottom of the second pore is drained by a suction pump.The draft rate (dope discharge linear speed/yarn take-off speed) is set to 7 by the above means. The physical properties of the obtained fibers are shown in Table 1 by spinning at each spinning speed and set differential pressure. It was confirmed that the take-up tension was at an extremely low level compared to the known spinning method (Comparative Example 1) at the same spinning speed, and that fibers with excellent fiber properties, strength, and elongation could be obtained. C.

In addition, at each spinning speed, in the method of the present invention, the coagulated liquid and the threads could be separated extremely efficiently and the threads could be taken out without disturbing them, so the resulting fibers had almost no so-called fuzz. I couldn't.

On the other hand, in the known spinning method that does not pass through a vacuum tube, which was carried out as a comparative example, as the spinning speed increases, the coagulation liquid scatters more frequently at the direction change roll section, and the cut single yarn is wound around the direction change roll. The fibers obtained with a large amount of fluff were found to have a lot of fuzz, and were significantly inferior to the fibers obtained by the method of the present invention in terms of fiber physical properties and quality.

Comparative Example 1 Using the same polymer solution as in Example 1, 0.07
The material was extruded into a coagulation bath through a spinning nozzle having a hole diameter of 5 m and 100 holes.

The coagulating bath, coagulating liquid composition, and temperature were the same as in Example 1, and a pore with an inner diameter of 2 mm and a length of 3 mm was installed at a depth of 40 mm from the surface of the coagulating bath liquid, and the coagulating liquid was dropped together with the thread. After changing the direction of the yarn using a direction change roll 450 degrees below the pores, fibers were obtained by the same treatment as in Example 1.

The physical properties and take-up tension during spinning of the obtained fibers are also listed in Table 1, and the fibers were significantly inferior to the fibers obtained by the method of the present invention in terms of physical properties and quality.

Examples 2-4 Poly-bara phenylene terephthalamide with ηinh of 7.96 was dissolved in 99.7% concentrated sulfuric acid at a polymer concentration of 1 s.
, s% for 2 hours at 70°C.

Dissolution was carried out under vacuum, and the mixture was left to stand for 2 hours to defoam before being used for spinning.

This dope was extruded from a spinning nozzle having a pore diameter of 0.07 ia+ and a number of holes of 500 so that the draft rate was 7.3, and was extruded once using the device shown in FIG. After traveling through the straw space, it was introduced into a coagulation bath in which the coagulation liquid was water and a 15-thiosulfuric acid solution whose temperature was kept at 0 to 3°C, and spinning was performed under the spinning conditions shown in Table 2. At that time, the pores installed at the bottom of the coagulation bath had the shape shown in Fig. 2-(B), had an inner diameter of 4.5mm and a length of 10+u, and were formed from the surface of the coagulation bath. It was installed at a depth of 60 meters.

In addition, three stainless steel perforated plates having the structure shown in Fig. 2 were placed 600 m below the pores.
The pore plate of each stage has a thickness of 3u, the gap between each stage is 2mm, and the diameter of the pore of the top stage is 4uφ at the upper end and 4uφ at the lower end. Similarly, the pores in the second row are 3.5 +uφ, 2.5 to φ, and the bottom row is 3uφ,
It consists of 211ulφ.

After the yarn thus formed in the coagulation bath was changed direction with a change-of-direction roll, it was pulled with a Nelson roll (9), and then with the device shown in Japanese Patent Publication No. 55-9088 (Fig. 3). That is, the yarn was transferred onto a reversing net by a pair of gear nip rolls (gear-shaped rolls are shallowly engaged and the yarn is fed out between them), and then the yarn was reversed and placed on a processing conveyor. The thread piles placed on the processing conveyor are washed with water using a single shower system, then treated with an oil solution containing 1% mineral oil dispersed in water using an emulsifier, and then dried with hot air at 200°C. After doing so, it was picked up from the conveyor and rolled onto the top bottle by a wine gourd.

The performance of the fiber thus obtained is shown in Table 2. The performance of the fiber in the method of the present invention is that the coagulation liquid is 15%
Even when an aqueous sulfuric acid solution was used, it was proved that it had high strength and particularly high elongation, and was extremely excellent even at high spinning speeds of 600 m 7 min or more.

In Table 2, aoo was prepared by a conventionally known method.
The physical properties of the fiber obtained at a spinning speed as low as m/min were also listed as Comparative Example 2, but even though the fiber in the method of the present invention was obtained at a spinning speed more than twice as high as that, The fiber properties were excellent in both strength and elongation, demonstrating how superior the method of the present invention is.

JP-A-Sho GO-94617 (13) The results of fatigue resistance measurements using the fibers obtained in Examples 2, 3.4 and Comparative Example 2 are as shown in Table 3 below, and are consistent with this book. The fibers obtained by the invention method were proven to have extremely excellent consumption performance, reflecting their excellent fiber properties.

Table 3 Comparative Example 2 The same spinning dope as that used in Examples 2 to 4 was used, and after being discharged into a space under the same discharge conditions, it was introduced into a coagulation bath. Next, a coagulation bath was installed at a depth of 60 mm from the surface of the coagulation bath.
The yarn and the coagulation bath were dropped through the same pores as those used in the lower part of the coagulation bath in the examples, and the pores were 6ooU.
After changing the direction of the yarn with a direction change roll below, Example 2
In the same manner as in ~4, the threads were washed with water on a conveyor and dried to obtain fibers. The physical properties of the obtained fibers are also listed in Table 2, and as mentioned above, they were significantly inferior to the fibers of the present invention.

[Brief explanation of drawings]

FIGS. 1 and 3 show a spinning apparatus suitable for carrying out the IJJJ method of the present invention, and each part is as follows. 10-... Decompression chamber, 11... Thin tube or pore provided at the bottom of the coagulation bath, 12... Second thin tube or pore, 13...
... Nozzle for decompression exhaust, 14 ... Nozzle for draining coagulated liquid, 15 ... Coagulated liquid that fell and stayed, 20 ... Coagulation bathtub, 21 ... Coagulated liquid, 22 ... Coagulated liquid Supply nozzle, 23... Nozzle for reducing coagulation liquid, 24... Chamber for pressurization, 25... Nozzle for pressurizing coagulation bath liquid, 30...
・Roll guide for yarn direction change, 40... Spinneret, 5
0... Thread and overflow coagulated liquid bundle, 60... Thread. Figures 2-(4)-(c) are enlarged views of some preferred embodiments of the capillaries or pores shown in Figure 1 11.12. In Fig. 3, 74...Nelson roll for take-up, 75...Gear nip roll, 76...Reversing net, 77...Conveyor net for sending yarn pile, 7
8... Shower tray for washing with water, 79... Hot air dryer, 80... Winder for winding up, 81... Cover net for holding down thread piles. Patent applicant: Asahi Kasei Industries, Ltd. Figure 1 Figure 2 (A) Figure 2 (B) Figure 3 Procedural amendment (voluntary) April 1980, Commissioner of the Japan Patent Office Kazuo Wakasugi, Mr. L Case Indication of 1982 Patent Application No. 197600
No. 2 Name of the invention 2ie IJ-No. 45 Process for manufacturing phenylene terephthalamyl fiber a Relationship with the case of the person making the amendment Patent applicant 1-2-6 Dojimahama, Kita-ku, Osaka-shi, Osaka Prefecture Subject of the amendment Akira at "Claims" and "Detailed Description of the Invention"
Column 5, Contents of amendment (1) The statements from page 1, line 6 of the specification to page 2, line 15 of the same book (statement of claims) are amended as shown in the attached sheet. (2) On page 4, line 8 of the specification, l'-PPTAJ is
Correct to PPTA type. (3) Statement on page 6, line 13 of the specification [P P T
Correct AJ to "PPTA system". (4) The statement on page 7, line 2 of the specification “p P T A
J is corrected to 1'-PPTA system. (5) Statement on page 7, line 5 of the specification “p P T A
Corrected to J gold “PPTA series”. (6) The statement in page 8, line 14 of the specification, ``is installed in the lower end of an integrated sealed structure'' is replaced with ``a second thin tube or pore is provided in the upper end and the lower end, respectively.'' A sealed room is installed together with the coagulation bath, and the correction is made to ``. (7) The first sentence on page 20, line 4 of the specification, “via a non-solidified fluid layer” is corrected as follows. "By making the non-coagulable fluid layer in the upper part of the coagulation bath into a closed structure including the spinneret 2-gold, and increasing the pressure of the non-coagulable fluid layer above atmospheric pressure" (8) Page 20 of the specification, No. 5 Line ``The sealed room''
[Corrected to the sealed room (hereinafter referred to as the decompression room). (9) The statement "closed room" on page 20, line 8 of the specification is corrected to "decompression chamber." Second: The description on page 20, line 18 of the specification has been corrected to "closed room" and "decompression chamber" in purple. aI) The statement "retention" on page 21, line 8 of the specification is amended to "excessive retention." Mackerel The description from page 21, line 16 to line 19 of the specification, ``Integrated sealed room QOI...by suction'' has been changed to ``decompression exhaust nozzle (1□□□
are arranged at the upper and lower ends of a decompression chamber αQ integral with the coagulation bath (20), respectively. This is corrected to ``by reducing the pressure inside the vacuum chamber by suctioning upward into the vacuum exhaust nozzle (13). α3) Insert the following sentence in place of the statement "I can do it." on the second line of page 22 of the specification. "At this time, the coagulating liquid that accompanies the yarn and is not discharged from the second capillary or pore together with the yarn may be discharged from the vacuum exhaust nozzle at the same time as the exhaust, but the coagulating liquid may be discharged separately. It is also a preferable embodiment to provide a spray nostle (141) in the decompression chamber 00 and suction and discharge." (14) The statement "should" on page 24, line 8 of the specification is replaced with "it is desirable." Q51 #J Detailed Declaration, page 25, No. 1, Preferably all 1, amended to ”. Insert. ``Measurement method of coagulating liquid speed> The coagulating liquid speed is measured while spinning is being carried out. In other words, while the yarn is being drawn continuously at a predetermined spinning speed, The coagulating liquid that flows out together with the yarn is collected from the thin tube or pore provided at the bottom of the coagulating liquid for a certain period of time, and its volume is measured to calculate the unit time (m”/min) of the coagulating liquid. This value is divided by the cross-sectional area (m2) of the capillary or pore provided at the bottom of the coagulating liquid used at this time to obtain the coagulating liquid velocity. ), when using a combination of capillaries or pores with different diameters,
Regarding the cross-sectional area of the tubule or pore, the coagulation liquid velocity is calculated using the cross-sectional area of the smallest diameter of the tubule or pore. 07) Statement from page 34, line 18 to line 19 of the specification [S. "Measured with S polysulfate..." is deleted. a~ Description from the last line of page 35 of the specification letter to the second line of page 36 of the same document: ``On the bottom plate of the coagulation bath... (diameter 200
m, depth 100non), and a cylindrical coagulation bath (a) with a diameter of 200mm and a depth of 100mm, and an inner diameter of 1'20 l1rn and a length of 450mm, which integrally contacts the bottom plate of the bath.
Corrected to ``mm vacuum chamber and''.゛H The description "closed room" on page 36, line 6 of the specification is corrected to "decompression chamber 00)." (2) Description from Ming, supra, No. 36, line 9 to line 12 of the same page 1 430 an below the pore...
Liquid 5 - Nozzle Q4) is attached, 1" [also reduced pressure (
IQ+ has 4 3 (l
The lower blade also has a pore (12) with an inner diameter of Imm and a length of 3mm, as shown in Figure 2 (B), and a vacuum exhaust nozzle (1:1) and a drainage nozzle (14) on the side. (21) Ifr on page 36, line 15 of the specification: @
Correct "Iso adjustment" to "Sama adjustment". (22) Description I in Table 1 on page 38 of the specification JJn pressure channel internal pressure (1'l/crn"G) J and sealed part internal pressure [decompression chamber pressure (Ky/1tn2) j are respectively "
Pressurized chamber internal pressure (Ren 7 Kuni 2)” and “Decompression guide pressure (
K7/Rep. 2)". (23) The entire description from page 36, line 10 of the specification to line 16 of the same document is changed to ``For comparison, the conventional spinning method, that is, the first knife-pressing channel (24) and the second tube (121
All examples are shown in which spinning was performed using a coagulation bath having the same structure as in Example 1 except that the reduced pressure ¥Q (2) was removed. ”. (24) Se listed on the 40th negative line of the 10th line of the clear f#i oath [Tatsumono 6 - was. ”, followed by astronomy as a matchmaker. "Furthermore, in the non-comparative example, which is a known spinning method that does not pass through a vacuum cylinder, as the spinning speed increases, the coagulation liquid scatters more frequently at the direction change roll section, and the cut eruption rate yarn is There was a lot of curling, and the obtained fibers were found to have a lot of fuzz, and as mentioned above, the fiber properties were not affected and the quality was significantly inferior to that of the fibers obtained by the method of the present invention.'' (25)
) E! A. Hosotoyo 42 Negative line 13 to line 15 of the same page describes ``A method that is conventionally known......It was also listed as Comparative Example 2,'' ``Comparative example that is a publicly known method.'' 1
Fibers obtained by the same method at a low spinning speed of p3oom, ,' minutes are listed as comparison column 2, but are corrected to ". (26) Statement box 43 Negative entry in Table 2 1 - Pressurized chamber - Internal pressure (h/cm2G) (27) Description from the 5th line from the bottom of page 44 of Ming #1 tatami mat to the 3rd line from the bottom of the same page [Examples 2 to 4] "The same as the one used... led to the coagulation office." is corrected as astronomical. For comparison, the conventional spinning method, that is, the pressurizing channels (24), the second pores (12), and the vacuum tail of the spinning apparatus shown in FIG. 1 used in Example 2-4 was used. An example of spinning using the removed spinning device t is shown below. In this comparative example, the same spinning dope as used in Example 2-4 was discharged under the normal discharge conditions and the dope was run through a space of 10 degrees. (29) Insert Astronomical information and Table 4 between page 45, line 6 of the specification, and line 7 of the same negative line.Example 1 + I15 Coagulation shown in Figure 2 used in Example 1 Using cypress, 1710 mol of paraphenylene diamine in PPTA was replaced with 4,4'-diaminobenzoanilide as the polymer.
Spinning was carried out in the same manner as in Example 1, except that a copolymer with N1nh of 5.1 was used, and a dope dissolved in 99.0% concentrated sulfuric acid to give a polyisotropy of 19★ was used. The properties of the obtained fibers are shown in Hokuzen No. 4 along with the results of Comparative Examples 3 and 4. Comparative Example 3 In Example 5, spinning was carried out in the same manner as in Example 5, except that the vacuum exhaust nozzle of the apparatus shown in FIG. 2 was not opened to the atmosphere and the pressure in the vacuum chamber was not set to 0 and 1 pressure. Comparative Example 4 From the apparatus shown in FIG. 2 used in Example 5, the fibers pulled out from the vacuum chamber (second pore αat-removal, pore (I) at the bottom of fQl) were directly transferred to the change roll (30). The spinning was carried out in the same manner as in Example 5, except that the material was changed so as to lead to the fibers. In the wet spinning method in which an anisotropic solution is introduced into a coagulation bath through a non-coagulable fluid layer, threads are pulled out along with the coagulation liquid flow from a hole or hole provided in the lower part of the internal temperature, and then passed through a brewing tube. Or through the pores and all the holes at the bottom.
After passing through the system through the installed second capillary or pore, the cough threads are subjected to finishing treatment steps such as washing 1 and drying. By pressurizing the coagulation bath liquid through the fluid layer and reducing the pressure in the sealed chamber, the flow of the coagulation liquid in the capillary or pore at the bottom of the coagulation bath is accelerated, and the flow rate in the second capillary or pore below is increased. Borinozoraphenylene terephthalamine P whose characteristic is to reduce the speed of
Manufacturing method of fibers

Claims (2)

[Claims] (1) In the wet spinning method in which a solution exhibiting optical anisotropy of a poly-paraphenylene terephthalamide polymer is introduced into a coagulation bath through a non-coagulable fluid layer, a thin tube or thin tube provided at the bottom of the coagulation bath is used. The yarn is pulled out from the hole along with the coagulating liquid flow, and then the yarn is passed through a second capillary or pore installed via a space below the capillary or pore, and then the thread is When subjected to finishing processes such as washing and drying, the thin tubes or pores at the bottom of the coagulation bath are installed at the upper and lower ends of an integrated sealed chamber, and the coagulation bath liquid is passed through a non-coagulable fluid layer. The flow rate of the coagulating liquid in the lower tubes or pores of the coagulation bath is accelerated by pressurizing the liquid and reducing the pressure in the sealed chamber, and the flow rate in the second tube or pores below is reduced. Method for producing poly-paraphenylene terephthalamide fiber (2) The spinning speed must be at least 6 oo m/min or more, and the second
, an index (WB
/Vlp) satisfies the following formula (1), and the differential pressure Δp between the pressurized fluid layer and the inside of the sealed room satisfies the following formula (2). 425≦'p 0-20
x (We,”□p)−〇・11 (1)0.74
X10-'V"≦Δp≦3.40X10-6・V" (
2) [However, in formula (1) I (2), T is the pulling tension p of the yarn (174), and Ws/Wp is the polymer weight 1 in the yarn taken out from the second capillary or pore. (Wp)
Δp is the differential pressure (Kt/d), and V is the spinning speed (m/+). ]