JPH0211626A - Production of wholly aromatic polyester - Google Patents

Abstract

PURPOSE:To obtain the title polyester which can give a molding improved in mechanical properties and thermal properties by polycondensing specified compounds in a reaction tank having a vertical agitating element and continuing the reaction in a reaction tank having a horizontal agitating element. CONSTITUTION:At least one compound selected from among an aromatic hydroxy carboxylic acid (derivative), an aromatic dicarboxylic acid (derivative) and an aromatic dihydroxy compound (derivative) is polycondensed at 125-400 deg.C for 1-15hr in at least one reaction tank having a vertical agitating element to a melt viscosity of 50-500P, and this reaction is (dis)continuously conducted at 250-450 deg.C for 1min-1hr in at least one reaction tank having a horizontal agitating element to obtain a wholly aromatic polyester of an inherent viscosity [in pentafluorophenol, 0.1(wt./vol.)% at 60 deg.C] of 3-10dl/g, which can form an optically anisotropic molten phase at 400 deg.C or below.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing wholly aromatic polyester that provides various molded articles with excellent mechanical and thermal performance.

[Conventional technology]

In recent years, industrial demands for higher performance organic polymer materials have been increasing, and various molding products such as fibers, films, and injection molded products with excellent mechanical properties such as strength and modulus of elasticity and thermal properties such as heat resistance have been increasing. products are highly desired.

As polymer materials that meet the above requirements, polyesters that form an optically anisotropic melt phase, so-called thermotropic liquid crystal polyesters, have attracted attention, and thermotropic liquid crystal polyesters with many structures have already been commercialized. ,
Some of them have come to be manufactured industrially in recent years.

Since the molecular chains of such polymers are easily aligned in one direction, various molded products that are highly oriented and have excellent mechanical properties can be obtained from these polymers. Furthermore, it is known that various molded products obtained from wholly aromatic thermotropic liquid crystal polyesters composed only of aromatic rings have extremely good heat resistance.

[Problem to be solved by the invention]

Fully aromatic thermotropic liquid crystalline polymer compounds, especially fully aromatic thermotropic liquid crystalline polyester, are excellent as high-performance materials, and compounds with many different structures have already been proposed.

According to the studies conducted by the present inventors, due to the special rheological properties of liquid crystal polymers, when producing fully aromatic thermotropic liquid crystal polyesters, difficulties that do not occur in the production of ordinary polymer compounds that do not form liquid crystals are encountered. However, there are still some issues that need to be resolved. That is, the melt viscosity of a liquid crystal polymer in a molten state is very low under shearing force, but the viscosity increases significantly in a static state without being subjected to shearing force. Therefore, during the polycondensation reaction, if the degree of polymerization exceeds a certain value as the reaction progresses, uniform stirring becomes difficult.
A portion of the reaction vessel is not subjected to shearing force.

This part becomes substantially non-flowing in the reaction tank and has a different composition or molecule 1, etc. from other parts, making it impossible to produce a polymer with a uniform composition. Therefore, the polymer can be obtained by a small-scale laboratory reaction. Physical properties are often inferior to polymers. Furthermore, when attempting to produce a fully aromatic thermotropic liquid crystalline polyester with a molecular weight of 1 that has sufficient physical properties as a molded product using only a reaction tank equipped with a normal vertical stirring blade, it is difficult to achieve uniform stirring as described above. In addition, it becomes extremely difficult to take out the polymer from the reaction tank after the polycondensation reaction is completed. In other words, as mentioned above, the viscosity of thermotropic liquid crystal polyester becomes extremely high in a static state where no shearing force is applied, so if stirring is stopped after the reaction is completed, the polymer does not flow and is taken out from the bottom of the reaction tank. This makes things difficult. Even if the polymer is discharged while stirring, the discharge efficiency will be extremely poor.

As described above, several problems remain to be solved if a wholly aromatic thermotropic liquid crystal polyester is to be produced efficiently and uniformly.

[Means to solve the problem]

The present invention relates to aromatic hydroxycarboxylic acids and/or their derivatives, aromatic dicarboxylic acids and/or their derivatives, and aromatic dihydroxy compounds and/or their derivatives.
A method for producing a wholly aromatic polyester that forms an optically anisotropic melt phase from at least one kind selected from the group consisting of polyesters and their derivatives by melt polycondensation reaction. The above reaction tank,
Subsequently, polymerization was carried out using a combination of some reaction vessels having horizontal stirring blades, and polymerization was carried out until the apparent melt viscosity under stirring conditions in the last reaction tank having vertical stirring blades was 50 to 500 poise. After that, the reaction is continued continuously or discontinuously in a reaction tank having horizontal stirring blades, and the wholly aromatic polyester is taken out from the reaction tank having horizontal stirring blades. This paper relates to a method for producing a wholly aromatic polyester that forms an anisotropic melt phase.

In the present invention, the polycondensation reaction is carried out by combining one or more types of reaction vessels having vertical stirring blades and one type of reaction tank(s) having horizontal stirring blades following the reaction tank(s), and also having vertical stirring blades. This is a sign in the final reaction tank. This makes the molecular weight and composition comparable, and improves the efficiency of discharging the polymer from the reaction tank after the reaction is completed.

The reaction tank having a vertical stirring blade used in the present invention means a stirring blade of any shape, such as a helical ribbon type,
It is a vertical reaction vessel of any shape, including a double helical ribbon type, turbine type, paddle type, squid type, etc., in which the contents can be mixed in a state close to complete mixing. (hereinafter referred to as a vertical reaction tank) In the above vertical reaction tank, the clearance between the stirring blade and the wall of the reaction tank should be as small as possible, and the compounds in the reaction tank should be efficiently and uniformly stirred. In order to achieve this, it is preferable that the average shear rate in the tank is 2 sec-1 or more.

The reaction vessel with horizontal stirring blades used in the present invention refers to a circular type, a double-threaded type, which has two or more axes, and which rotates in the same direction at an arbitrary angle to the 1-1 axis. This is essentially a piston flow type reaction tank equipped with stirring blades in the shape of a three-threaded screw. (Hereinafter, it will be referred to as a horizontal reaction tank.) The shapes of the circular, two-thread type, and three-thread type stirring blades are illustrated in FIGS. 1 to 3.

It is desirable that the reaction tank has self-cleaning properties in order to eliminate polymer stagnation throughout the horizontal reaction tank and obtain a uniform polymer.

In addition, in order for the polymer to be mixed uniformly throughout the horizontal reaction tank and to prevent the formation of so-called gelled products, it is necessary to ensure that the peaks of the stirring blades of the reaction tank (or the outer periphery if the stirring blades are circular) and the reaction tank The shear rate at the place where the wall thickness is the smallest is 2
It is desirable that it is 00 seconds゛1 or more.

In the present invention, a polymer having a relatively low degree of polymerization is first produced in a tank or one or more vertical reaction tanks.

When using a compound having a hydroquinol group as a starting material compound, the compound is first reacted with a lower aliphatic acid anhydride, preferably acetic anhydride, in a vertical reaction tank to convert substantially all the hydroquinol groups into corresponding acyl groups. Conversion into the ester, preferably acetate form. The reaction is carried out at 125°C to 200°C in the presence of an inert gas at normal or elevated pressure.
The temperature range is usually 10 minutes to 10 hours.

After the completion of this esterification reaction, the reaction mixture can be used as it is in the next polycondensation step, or the polycondensation reaction can be carried out after the produced acyl ester is isolated. The polycondensation reaction is carried out in the same reaction tank used for the acyl esterification, or in a separate vertical reaction tank, in the presence of an inert gas, under normal or increased pressure, or under reduced pressure. The excess lower aliphatic acid anhydride used in the acyl esterification reaction, the lower aliphatic acid compounds by-produced by the esterification reaction, and the lower aliphatic acid compounds produced by the polycondensation reaction are continuously removed from the reaction tank. Targeted or discontinuous? This is done while removing this.

The polycondensation reaction in a vertical reactor is usually carried out at a temperature within the range of 125°C to 400°C, preferably 150°C to 350°C. The rotational speed of the stirring blade depends on the shape of the stirring blade used and the viscosity of the product, but is usually within the range of 20 to 200 revolutions per minute.

In the method of the present invention, it is important to stop the polycondensation reaction when the apparent melt viscosity is within the range of 50 to 500 voices under stirring conditions in the final vertical reaction vessel. Apparent melt viscosity under stirring conditions refers to the melt viscosity under shearing force and at reaction temperature determined by the shape and rotational speed of the stirring blade, and is usually measured by measuring the torque of the stirring blade in the reaction tank. It can be found by If the viscosity is less than 50 voices, the degree of polymerization of the polymer compound obtained from the reaction tank is too low, and in order to obtain the final product in which the molecule 1, which is desirable for various molded products, is obtained, it is necessary to use a horizontal reaction tank. This is undesirable because the IJ polycondensation reaction time becomes longer and a large-capacity horizontal reaction tank is required.If the apparent melt viscosity in the final vertical reaction tank exceeds 500 poise, It is difficult to efficiently perform uniform stirring due to the nuclide, and not only is it impossible to obtain a polymer with a uniform composition, but also the efficiency of discharging the polymer from the reaction tank after the reaction is completed is significantly reduced.

After continuing the polycondensation reaction in the final vertical reactor until the melt viscosity falls within the above range, the polymer is taken out in a molten state and transferred to the next horizontal reactor in its molten state, where it is continuously further reacted. The polycondensation reaction can continue. In addition, after the polymer taken out from the vertical reaction tank is cooled and solidified, it is cut or crushed into a yellow shape, melted again, and further polycondensation reaction is carried out in the horizontal reaction tank. It can also be adopted.

In the horizontal reactor, the polymer taken out from the reactor has a concentration of 3 to 1 Odl/g, preferably 3.5 to s when measured at 60° C. in 0.1% w/v in pentafluorophenol. The melt polycondensation reaction is carried out until the degree of polymerization is expressed as a logarithmic viscosity of di/g.

In the horizontal reaction tank, if a lower aliphatic acid compound produced as a by-product in the polycondensation reaction is used, for example, an acetate ester of an aromatic hydroxyl compound as a starting compound, acetic acid cannot be distilled out from the reaction tank. For convenience, the pressure is usually reduced, for example from about 500 to 0. The reaction is carried out within lmmHg. The reaction temperature in the reaction tank is 2
50°C to 450°C, preferably 280°C to 400°C
The residence time is selected from the range of 1 minute to 1 hour. The rotational speed of the stirring blade of the reaction tank is 1
It is selected from within the range of 50 to 300 revolutions per minute.

If the logarithmic viscosity defined above of the obtained wholly aromatic polyester is less than 3 dl/g, the physical properties of various molded products obtained from the polyester are undesirably low. If the logarithmic viscosity exceeds 10 dl/g, the physical properties of various molded products obtained from the polyester will be lower than when the logarithmic viscosity is 1 odl/g or less, and the melt moldability will also deteriorate, which is undesirable.

By forming an optically anisotropic melt phase, melt moldability is significantly improved compared to the case where an optically anisotropic melt phase is not formed, and the physical properties of various molded products obtained from the polyester, For example, strength, elastic modulus, impact strength, etc. are significantly improved.

It is preferable that the wholly aromatic polyester obtained by the production method of the present invention forms an optically anisotropic melt phase at a temperature of 400° C. or lower. Confirmation of the formation of an optically anisotropic molten phase is carried out by thin sectioning the sample under a polarized light microscope equipped with a heating device, preferably 5-20 μff
This can be done by inserting a thin section of about i in size between cover glasses and observing it under a constant heating rate, and observing that light passes through at a constant temperature or higher. In this observation, the temperature at which polarized light begins to pass through is the transition temperature to an optically anisotropic molten phase.

The starting material compounds used in the method of the present invention include at least one of aromatic hydroquine carboxylic acids and/or derivatives thereof, aromatic nocarboxylic acids and/or derivatives thereof, and aromatic dihydroquino compounds and/or derivatives thereof. Selected from one or more types.

Specific examples of aromatic hydroquinocarboxylic acids include 4-hydroxybenzoic acid, 2-hydroquine-6=naphthoic acid,
4-(4-hydroxyphenyl)benzoic acid etc. and 4-
Ester derivatives such as acetoquine benzoic acid can be mentioned.

Specific examples of aromatic dicarboxylic acids include terephthalic acid,
Isophthalic acid, 4,4'-dicarboquine diphenyl, 2
．． Examples include ester derivatives such as 6-dicarboquinnaphthalene, 27-dicarboquinnaphthalene, 1,2-bis(4-carboquinphenoquine)ethane, and tumethyl terephthalate.

Specific examples of aromatic dihydroxy compounds include hydroquinone, 4.4'-dihydroxydiphenyl, 4.4'-
Dihydroxybenzophenone, 4,4'-dihydroquinonophenyl ether, 4,4'-nohydroquinonophenyl sulfone, 4,4'-dihydroquinodiphenyl sulfide, 2,6-cyhydroquinonaphthalene, etc., and 4.
Ester derivatives such as 4'-noacetoquinnophenyl can be mentioned.

Preferably, the following structural formula 1. Compounds represented by It and
．． Represents a 6-naphthalene group. ) HOOC-Ar'-COOH (in the formula, Ar is
It is a divalent group consisting of at least one or more aromatic groups, and at least 50 mol% or more of the endogenous groups are linearly oriented groups. ) [11,HO-Ar-OH (In the formula, Ar is a 4,4'-diphenyl group and/or a 4,4'-diphenyl ether group.) Compound I is 30 to 80 mol% based on the total 1 , Compound ■ is used in an amount within the range of IO to 35 mol%, Compound ■ is used in an amount within the range of 1° to 35 mol% (However, Compound ■ and Compound ■ are used in an amount of IO,
/9 to 9/10).

Compound 1 is an aromatic hydroxylic acid compound and its derivative, Ar is a 1,4-phenylene group and/or a 2,6-naphthalene group, preferably a 1,4-phenylene group.

When 8r is used in combination with a 26-naphthalene group in addition to a 1,4-phenylene group, it is preferable in terms of melt molding processability of the obtained wholly aromatic polyester. In that case, the molar ratio of 4-okinobenzoyl moiety to 6-oxy-2-naphthoyl moiety is in the range of 20/l to 1/20, but 6-hydrokylar 2-naphthoic acid is more expensive. Therefore, it is industrially preferable to have a large proportion of 4-oxybenzoyl moiety. It is also possible to use only the 6-oxy-2-naphthoyl moiety, but this is not preferred industrially for the same reason.

Compound 1 is added in an amount of 30 to 8 with respect to the total amount of raw material compounds used.
It is used in an amount of 0 mol%, preferably in the range of 40 to 70 mol%.

The compound is an aromatic nocarphonic acid compound and its derivatives, and Ar' is a divalent group consisting of at least one aromatic ring, and at least 650 mol% of it has linear orientation. It is the basis.

Here, the linear orientation means that the CO groups are located linearly symmetrically across the aromatic ring. Specific examples of Ar' include 1,4-phenylene group, 2,6-naphthalene group, 4
．． Examples include 4'-diphenyl group and 1,3-phenylene group, but 1,4-phenylene group is preferable from the viewpoint of raw material cost and physical properties of the obtained wholly aromatic polyester.

Compound ■ is 10 to 3 to 1 of the total raw material compounds used.
1 in the range of 5 mol%, preferably 15 to 30 mol%
used in

Compound (1) is an aromatic hydrogine compound and its derivatives, and Ar'' is a 4,4'-diphenyl group and/or a 4,4'-diphenyl ether group.
″ is a 4,4′-diphenyl group and a 4,4′-diphenyl ether group, and 4,4′-diphenyl and 4
The molar ratio of 4'-diphenyl ether group is 872 to 1/9
It is preferable from the viewpoint of the moldability of the obtained wholly aromatic polyester and the physical properties of various molded products obtained from the polyester. Compound (1) is present in an amount of 10 to 35 mol%, preferably 15 to 30 mol%, based on the total amount of raw material compounds used.
It is used in amounts within the range of mole %.

Compound (1) and compound (2) are used at a concentration within the range of 10/9 to 9/1O, and the molar ratio of repeating units derived from compound (1) and compound (2) in the produced wholly aromatic polyester is substantially equal to 1 and (1). It is used as follows. In other words, if compound ■ and compound ■ do not scatter out of the system during the polycondensation reaction, compound ■ and compound ■ are used at substantially the same amount of 1, and if either of them scatters, it depends on the amount of scattering. , Compound (1) or Compound (2) may be used in excess.

Although the polycondensation reaction can be carried out without the use of a catalyst, it is about 0001 to 1% by weight of the total leather carcass weight, preferably about o, o
When a known transesterification catalyst is used in the range of 0.5 to 5%, favorable results may be obtained in terms of polymerization rate. Specific examples of transesterification catalysts include alkali or alkaline earth metal salts of carboxylic acids;
Examples include alkyltin quinides, diaryltin oxides, alkyltin acids, ditano dioxide, alfquin titanium silicate, ditane alkoxides, Lewis acids, and halogen heptanohydrogenides.

〔Example〕

Example I A vertical stirring type reaction tank with an inner diameter of 44 On+m, an internal volume of 70Q, a material of 5IJS316L, a double helical ribbon type stirring blade, and a reaction in which the clearance between the wall of the reaction tank and the stirring blade is 5 mm. A tank was used. Into the reaction tank were 20,720 kg of 4-hydroquine benzoic acid, 8.307 kg of terephthalic acid, 4.655 kg of 4.4-dihydroxodiphenyl, 5.055 kg of 4.4'-dihydroquinodiphenyl ether, and 28.07 kg of acetic anhydride.
I loaded 5 kg. After the system was sufficiently purged with nitrogen gas, the temperature of the oil bath in the reaction tank was raised to 150°C, and the mixture was refluxed for 2 hours with stirring. Note that the rotation speed of the stirring blade was 70 revolutions per minute.

After 2 hours, the internal temperature of the reaction tank was raised to 220℃ over 1 hour.
℃, then raised to 260℃ over 1 hour, and further heated to 260℃ for 1 hour.
The temperature was raised to 320°C over time and held at 320°C for 10 minutes. During this period, a total of 30.60 kg of acetic acid and acetic anhydride were distilled out. Next, the internal temperature of the reaction tank was raised to 340°C, and the pressure inside the reaction tank was gradually reduced to 50 wm over 40 minutes.
reached Hg.

During this time, the apparent melt viscosity of the reactant calculated from the torque meter gradually increased and reached 5o poise after 40 minutes. Furthermore, when the conditions were maintained at 340°C and 5 mffiHg while stirring, the apparent melt viscosity increased after 10 minutes! It reached 70 poise. At this point, nitrogen gas was introduced into the system to return it to normal pressure and stop the reaction. A portion of the sample was taken out from the reaction tank and 0.1% precious/volume in pentafluorophenol was taken out.
, the logarithmic viscosity was measured at 60'C and was 2.90.
It was dl/g.

Note that the logarithmic viscosity is calculated using the following formula.

Qn　L/l.

Fall time of pentafluorophenol, a solvent, when measured at 60°C using an Ubbelohde viscometer.

L: Falling time of the solution containing the sample.

C: Concentration of sample (g/dl) Next, the contents of this vertical reaction tank were continuously supplied as they were to a horizontal reaction tank directly connected to the reaction tank, and the polycondensation reaction was further continued.

The inner diameter of the reaction tank having horizontal stirring blades is 100 mm.
, the diameter is 1000 m+, it has a circular stirring blade that rotates in the same direction as shown in Fig. 1, the clearance between the outer periphery of the stirring blade and the wall of the reaction tank is IIIIIIll, and all the materials are 5US318. I used the one from

Using this reaction tank, push polymerization was carried out under the conditions of 340° C., 90 rotations per minute, reduced pressure of 5 nmHg, and residence time of 15 minutes. Note that under these stirring conditions, the shear rate at the location where the distance between the outer periphery of the stirring blade of the reaction tank and the wall of the reaction tank was the minimum was 470 sec-1.

Under the above conditions, the polycondensation reaction continues in a horizontal reactor,
The polymer was taken out in strand form and cut into pellets using a conventional strand cutter.

The logarithmic viscosity of the obtained polymer was 4.50 dl/g. The yield of the obtained polymer was 90
%Met.

Microscopic pieces of this polymer were heated under a nitrogen atmosphere in a microscope heating device TH-600 manufactured by Linkam.
When the temperature was raised at a rate of 0°C/min and observed under a polarizing microscope with crossed Nicols, light began to pass through from 293°C and reached 305°C.
Nearby, the transmitted light becomes even larger, confirming that this polymer forms an optically anisotropic molten phase.

The obtained polymer was molded using an injection molding machine 5S80 manufactured by Nisshin Jushi Kogyo Co., Ltd.
S +2ASE, barrel temperature 320℃, mold temperature 1
Injection molding was carried out under the conditions of 00°C and an injection pressure of 800 kg/cm" to create test pieces.The bending strength, flexural modulus, Izod impact strength, and heat distortion temperature of the obtained test pieces were measured using each method. The results are shown below.

Bending strength (JISK7023) 1700k
g/am” bending modulus (JISK7023) 1
3.4X 10'kg/c+i" Izot impact strength (JISK7110) with notch 54 kg
cm/an without notch 94 kgcm/cm'
Heat distortion temperature (ASTMD648) 259°C Example 2 In the vertical reaction tank used in Example I, 20.720 kg of 4-hydroquine benzoic acid and 8.307 te L/'7 taric acid were added.
kg.

4.4'-nohydroquine diphenyl 3.491 kg,
4.4'-nohydroxydiphenyl ether 6.3
19 kg and 28.075 kg of acetic anhydride were charged. The acetylation of the raw material compound and the subsequent polycondensation reaction were carried out under the same conditions as in Example 1. The reaction was stopped when the apparent melt viscosity calculated from the torque meter reached +50 poise, and the contents were taken out from the reaction vessel in the form of strands and pelletized. The yield of the pellet-like polymer was 94% based on the theoretical yield.

The logarithmic viscosity of the obtained polymer was measured in the same manner as in Example 1 and found to be 2.78 dl/g. Next, the pellets were mixed into a reactor with an inner diameter of 40 Ilr@, a moderate diameter of 1,680 am, made of nitrided steel, and equipped with two threaded screw-type stirring blades of the shape shown in Fig. 2 that rotate in the same direction with two wheels, and the stirring blades and the inner wall of the reaction tank. It was supplied to a horizontal reaction tank with a clearance of 0.3 mm between the
The polycondensation reaction was further continued under the conditions of rotation and residence time of 10 minutes. The shear rate of stirring under the above conditions was 1047 s-1. A single-screw extruder was directly connected to the front of the horizontal reaction tank, and the pellets were heated and melted in the extruder and supplied to the horizontal reaction tank. The polymer was taken out in the form of strands from the horizontal reaction tank and made into pellets.

The resulting polymer had a logarithmic viscosity of 3.68 dl/g, and formed an optically anisotropic melt phase at temperatures above 290°C.

Injection molding was performed in the same manner as in Example 1, and the physical properties of the test piece obtained were as follows.

Bending strength 1470 kg/am' Bending modulus 8.3X 10'kg/cm'
Izotsu impact strength with notch 93 kg+, n70m notch 1m
140 kzcm/cJ heat distortion temperature
251°C [Effects of the Invention] According to the production method of the present invention, a wholly aromatic polyester that forms an optically anisotropic melt phase can be efficiently and uniformly produced, and the polymer from the reaction tank can be uniformly produced. The discharge efficiency is good.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a horizontal reaction tank with circular stirring blades, Figure 2 is a cross-sectional view of a horizontal reaction tank with a double-threaded stirring blade, and Figure 3 is a cross-sectional view of a horizontal reaction tank with a double-threaded stirring blade. FIG. 2 is a cross-sectional view of a horizontal reaction tank having stirring blades. Inner wall of horizontal reaction tank 2 Stirring blade 3 Stirring shaft Patent applicant Rira Co., Ltd. Agent

Claims (1)

[Scope of Claims] 1. At least one selected from aromatic hydroxycarboxylic acids and/or derivatives thereof, aromatic dicarboxylic acids and/or derivatives thereof, and aromatic dihydroxy compounds and/or derivatives thereof, A method for producing a wholly aromatic polyester that forms an optically anisotropic melt phase by a melt polycondensation reaction, in which the reaction is carried out in one or more reaction vessels having vertical stirring blades, followed by horizontal stirring. Polymerization was carried out using a combination of a single reaction tank equipped with blades, and polymerization was carried out until the apparent melt viscosity became 50 to 500 poise under stirring conditions in the last reaction tank equipped with vertical stirring blades, and then An optically anisotropic polyester, characterized in that the reaction is continued continuously or discontinuously in a reaction tank having horizontal stirring blades, and the wholly aromatic polyester is taken out from the reaction tank having horizontal stirring blades. A method for producing a wholly aromatic polyester forming a molten phase. 2. Compounds represented by the following structural formulas I, II and III or their derivatives I, HO-Ar-COOH (wherein Ar is a 1,4-phenylene group and/or 2
, 6-naphthalene group. ) II, HOOC-Ar'-COOH (In the formula, Ar' is one or more divalent groups consisting of at least one aromatic ring, of which at least 50 mol% or more is a linear alignment group.) III , HO-Ar''-OH In the H formula, Ar'' is a 4,4-diphenyl group and/or a 4,4-diphenyl ether group. ) Based on the total amount, Compound I is 30-80 mol%, Compound II is 10-3 mol%
5 mol%, Compound III is used in an amount within the range of 10 to 35 mol% (However, Compound II and Compound III are used in an amount of 10/9 to 9
2. The method for producing a wholly aromatic polyester according to claim 1, wherein the molar ratio is within the range of /10. 3. When the wholly aromatic polyester is measured in pentafluorophenol at 0.1% w/v at 60°C.
The method for producing a wholly aromatic polyester according to claim 1, having a logarithmic viscosity of ~10 dl/g. 4. The method for producing a wholly aromatic polyester according to claim 1, wherein the wholly aromatic polyester forms an optically anisotropic melt phase at a temperature of 400° C. or lower. 5. Add the compound to the first tank, a reaction tank with vertical stirring blades.
I, II, and III and Compounds I and III were charged with 1.0 to 2.0 equivalents of acetic anhydride to the hydroxyl groups to convert substantially all of the hydroxyl into acetyl groups, and then In another reactor having one or more vertical stirring blades, the polycondensation reaction is carried out while the excess acetic anhydride and the acetic acid produced by acetylation are discharged, and the final vertical stirring blades are The apparent melt viscosity under stirring conditions in a reaction tank with 50
3. The method for producing a wholly aromatic polyester according to claim 2, wherein the polymerization is carried out until the polymerization temperature reaches 500 poise. 6. The reaction tank with vertical stirring blades is a helical ribbon type,
2. The method for producing wholly aromatic polyester according to claim 1, comprising a double helical ribbon type, turbine type, paddle type, or squid type stirring blade. 7. A reaction vessel with a horizontal stirring blade has two or more axes, has an arbitrary angle to the axis, and rotates in the same direction. The method for producing a wholly aromatic polyester according to claim 1, which is a reaction tank having wings. 8. The method for producing a wholly aromatic polyester according to claim 1, wherein the reaction tank having a horizontal stirring blade has self-cleaning properties. 9. The shear rate at the point where the distance between the peak of the stirring blade of a reaction tank with horizontal stirring blades and the wall of the reaction tank is the smallest is 200.
2. The method for producing a wholly aromatic polyester according to claim 1, wherein the temperature is at least 1 second. 10. The total residence time in the reaction tank with vertical stirring blades is 1
2. The method for producing a wholly aromatic polyester according to claim 1, wherein the time is from 15 hours to 15 hours. 11. The reaction temperature of the reaction tank with vertical stirring blades is 125
The method for producing a wholly aromatic polyester according to claim 1, wherein the temperature is from °C to 400 °C. 12. Residence time in a reaction tank with horizontal stirring blades is 1
2. The method for producing a wholly aromatic polyester according to claim 1, wherein the time is from 1 minute to 1 hour. 13. The reaction temperature of the reaction tank with horizontal stirring blades is 25
The method for producing a wholly aromatic polyester according to claim 1, wherein the temperature is from 0°C to 450°C. 14, Ar of compound 1 is a 1,4-phenylene group,
Ar'' of compound III is 4,4'-diphenyl group and 4
, 4'-diphenyl ether group. 3. The method for producing a wholly aromatic polyester according to claim 2. 15. Ar'' of compound III is a 4,4'-diphenyl group and a 4,4'-diphenyl ether group, and 4,4'
15. The method for producing a wholly aromatic polyester according to claim 14, wherein the ratio of -diphenyl group to 4,4'-diphenyl ether group is 8/2 to 1/9.