JPH1180338A - Method for producing liquid crystal polyester - Google Patents

Abstract

[Problem] To provide a method for producing a high-quality liquid crystal polyester having excellent heat resistance, which can increase the cleaning cycle in a can when producing a liquid crystal polyester, thereby improving productivity. I do. When a liquid crystal polyester raw material including a powdery liquid crystal polyester raw material and a liquid liquid crystal polyester raw material is charged from a raw material input port of a polymerization apparatus and heated and polycondensed to produce a liquid crystal polyester, the liquid liquid crystal polyester is produced. A method for producing a liquid crystal polyester, comprising adjusting a part or all of a raw material and a powdery liquid crystal polyester raw material into a slurry state, and then charging the raw material into a raw material charging port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a liquid crystal polyester. More specifically, the present invention relates to a method for producing a liquid crystal polyester of high quality, particularly excellent in heat resistance, by suppressing high melting point foreign substances generated by repeated batch polymerization in a melt polycondensation reaction.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for higher performance of plastics, and a number of polymers having various new properties have been developed and marketed. Above all, attention has been paid to optically anisotropic liquid crystal polymers characterized by parallel arrangement of molecular chains because of their excellent fluidity and mechanical properties.

As a method for producing a liquid crystal polyester, as disclosed in JP-A-1-149825, when the viscosity increases, the number of agitation is decreased to control the polymerization reaction temperature. As disclosed in the official gazette, the shear rate at the can wall surface is 10 to
It is known that polymerization is carried out at 100 (1 / second) while stirring in a direction in which the reactant is scraped.

[0004]

However, although a liquid crystal polymer excellent in quality can be produced by the conventional polymerization method, monomers and oligomers remaining in the reaction vessel after repeated batch polymerization receive heat history, It becomes a substance that deviates significantly from the desired polymer composition, for example, does not melt even at a melting point of 350 ° C., and mixes as a foreign substance into the polymer when discharged from the can after the polymerization, which adversely affects the physical properties of the obtained liquid crystal polymer. Therefore, it was found that the number of batch polymerizations could not be increased repeatedly, so that the inside of the can had to be periodically cleaned. Accordingly, the present invention provides a method for producing a liquid crystal polyester of high quality, especially excellent in heat resistance, by reducing the amount of monomers and oligomers remaining in the can and improving the productivity by extending the cleaning cycle in the can. Is to do.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.

That is, the present invention relates to (1) a method in which a liquid crystal polyester raw material including a powdery liquid crystal polyester raw material and a liquid are charged from a raw material charging port of a polymerization apparatus and heated and polycondensed to produce a liquid crystal polyester. A method for producing a liquid crystal polyester, comprising: adjusting a powdery liquid crystal polyester raw material to a slurry state;

(2) The method for producing a liquid crystal polyester according to (1), wherein the polymerization of the liquid crystal polyester includes an acylation reaction using an acylating agent and a deacetic acid reaction.

(3) The method for producing a liquid crystal polyester according to (1) or (2), wherein the liquid is acetic anhydride used as an acylating agent.

(4) The liquid crystalline polyester raw material according to any one of (1) to (3), wherein the powdery liquid crystal polyester raw material is at least one selected from aromatic oxycarboxylic acids, aromatic diols and aromatic dicarboxylic acids. Production method.

(5) The liquid crystal polyester raw material contains a polyester obtained by polycondensing an ethylenedioxy unit and an aromatic dicarbonyl unit.
(4) The method for producing a liquid crystal polyester according to any of the above.

(6) The method is characterized in that the powdery liquid crystalline polyester raw material and the liquid are slurried while being stirred at a temperature in the range of 20 ° C. to 120 ° C. and adjusted to a slurry state.
(5) The method for producing a liquid crystal polyester according to any one of (5).

(7) Slurry is performed using a slurry adjusting tank, and the stirring conditions in the slurry adjusting tank are such that the shear rate between the stirring blade and the tank wall is 150 to 1000 (1/1).
Second). (1)
The method for producing a liquid crystal polyester according to any one of (1) to (6).

(8) The liquid crystal polyester has the following (I):
The method for producing a liquid crystal polyester according to any one of (1) to (7), which is a liquid crystal polyester comprising the structural units of (II), (III) and (IV).

[0014]

Embedded image (However, R1 in the formula is

Embedded image R1 represents one or more groups selected from

Embedded image And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom. )

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal polyester produced in the present invention is a polyester capable of forming an anisotropic molten phase upon melting, for example, an oxycarbonyl unit such as an aromatic oxycarbonyl unit, an aromatic dioxy unit and an ethylenedioxy unit. And polyesters exhibiting melt anisotropy comprising units selected from dioxy units such as units and dicarbonyl units such as aromatic dicarbonyl units. The production method of the present invention is used when producing such a liquid crystal polyester.

In the present invention, there is no particular limitation on a basic reaction route for producing a liquid crystal polyester by polymerization, and it can be produced by a generally known method.
Raw materials that can constitute structural units of the liquid crystal polyester, that is, raw materials for liquid crystal polyester polymerization (liquid crystal polyester raw materials) include aromatic hydroxycarboxylic acids, dihydroxy compounds, aromatic dicarboxylic acids, polyesters composed of dioxy and dicarbonyl units, and Derivatives thereof can be mentioned, and these are obtained by appropriately combining these types and compositions and polymerizing.

Examples of the aromatic hydroxycarboxylic acid and its derivatives include p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and acylated products and phenyl esters thereof. As the dihydroxy compound, an aromatic diol is preferable.
4'-dihydroxybiphenyl, 3,3 ', 5,5'-
Tetramethyl-4,4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,
Examples include 7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, and 4,4′-dihydroxydiphenyl ether, and diacylated products thereof. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid,
2-bis (2-chlorophenoxy) ethane-4,4'-
Examples include dicarboxylic acid and diphenyl ether dicarboxylic acid, and diphenyl esters thereof. Examples of the polyester comprising a dioxy unit and a dicarbonyl unit include polyethylene terephthalate.

An aromatic oxycarboxylic acid or a derivative thereof, a diol or a derivative thereof, or an aromatic dicarboxylic acid or a derivative thereof, which can be a raw material that can constitute a structural unit of a liquid crystalline polyester, is often solid at ordinary temperature, It is preferably used as a powder. Further, the polyester comprising a dioxy unit and a dicarbonyl unit is solid at room temperature, but is usually used in the form of pellets or powder obtained by pulverizing it.

In the present invention, the reaction for producing the liquid crystal polyester can be carried out, for example, by subjecting the liquid crystal polyester to deacetic acid polymerization. In this case, the deacetic acid polymerization is performed using a raw material in which the hydroxyl group is pre-acylated, and the acylation in which the hydroxyl group is acylated using a hydroxyl group-containing monomer together with an acylating agent as a raw material constituting the liquid crystal polyester. Although the reaction and the deacetic acid polymerization reaction may be performed, the latter method is preferable.

In the present invention, 120 is used as the acylating agent.
It is preferable that the acylating agent can be in a liquid state at a temperature of not more than ° C, and specifically, acetic anhydride is preferable.

As a specific method, for example, the following (1)
A hydroxyl group-containing compound as represented by the method of
A method in which a hydroxyl group is acylated using a carboxylic acid group-containing compound and an acylating agent such as acetic anhydride, followed by deacetic acid polycondensation. In this method, a part of the hydroxyl group-containing compound is replaced with an acylated compound. Although the method described above is used, a method represented by the method (1) is particularly preferable.

(1) p-hydroxybenzoic acid, 4,4 '
Aromatic dihydroxy compounds such as dihydroxybiphenyl and hydroquinone, acylating agents such as acetic anhydride, aromatic dicarboxylic acids such as terephthalic acid, and polyesters or oligomers of ethylene glycol and aromatic dicarboxylic acids, or bis (β -Hydroxyethyl) ester to react with a phenolic hydroxyl group to thereby acylate the phenolic hydroxyl group, followed by a deacetic acid polycondensation reaction.

The polymerization proceeds even if this deacetic acid reaction is carried out in the absence of a catalyst. However, stannous acetate, tetrabutyl titanate,
Potassium acetate, antimony trioxide, magnesium, sodium hypophosphite effective as a catalyst or a catalyst and a color tone improver as a metal compound such as sodium acetate, and a compound such as potassium hypophosphite are preferably added. is there.

In the present invention, the liquid crystalline polyester is produced by charging a liquid crystalline polyester raw material including a powdery liquid crystalline polyester raw material and a liquid from a raw material charging port of a polymerization apparatus and heating and polycondensing the liquid. After the liquid crystal polyester raw material is adjusted to a slurry state, it is necessary to feed the raw material into a raw material charging port.

An important point in the present invention is to prevent the raw materials charged in the polymerization apparatus from being ununiform due to insufficient mixing, thereby suppressing an undesired polymer composition. In particular, when a polyester obtained by polycondensation of an ethylenedioxy unit and an aromatic dicarbonyl unit is included as a raw material of a liquid crystal polyester, generation of a high-melting-point foreign material due to nonuniform polymer composition is suppressed, and a homogeneous polymer is obtained. It is preferable because it can be obtained.

The polyester comprising ethylenedioxy units and dicarbonyl units is solid at ordinary temperature,
Usually, it is used in the form of a pellet or a powder obtained by grinding it.

The liquid crystal polyester is converted into an
In the case of carrying out acylation and deacetic acid polymerization, it is preferable to slurry the liquid crystal polyester raw material together with the acylating agent, and acetic anhydride is most preferred as the acylating agent.

In many cases, the raw materials for constituting the structural units of the liquid crystalline polyester are solid at room temperature to 120 ° C. or lower, and are often used as powders. Mix to form a slurry. As such a liquid, those which become liquid at 120 ° C. or lower are preferable, and specific examples thereof include acetic anhydride as an acylating agent or an inert medium such as acetic acid or a heating medium. Preferably, acetic anhydride is used.

Hereinafter, these points will be described in detail. There is no particular limitation on the method of mixing the powdery liquid crystal polyester raw material and the liquid to form a slurry, and any method may be used as long as it can uniformly form a slurry.

The average particle diameter of the powdery liquid crystal polyester raw material here is usually 1 mm or less, preferably 0.7 mm or less, more preferably 0.5 mm or less.
These are: The average particle size used here is a sieve of 5 to 600 meshes, and the number of meshes is small so that the relationship between one sieve and the sieve closest to it and having the largest number of meshes is about 1.5 to 2 times. Pile up from the bottom to the bottom, place a container without mesh at the bottom (so that the weight ratio remaining in the top and bottom containers is less than 5%), and shake Sieve using a sieve, determine the weight ratio of p-hydroxybenzoic acid remaining in each sieve, and multiply the average of the sieve mesh spacing and the sieve mesh size above it, Those remaining in the uppermost sieve multiply the opening intervals of the uppermost sieve, and those remaining in the lowermost container multiply the opening intervals of the sieve with the largest number of meshes.) It can be determined by.

In terms of the apparatus, it is preferable to provide a slurry adjusting tank provided with a stirrer separately from the polymerization apparatus.

As for the stirring speed for slurrying, the shearing speed between the stirring blade and the wall surface of the can is 150 (1 / sec) or more, especially 20
It is preferable to carry out at 0 to 700 (1 / sec). When the stirring speed is in such a range, the dispersion of the powdery liquid crystal polyester raw material is in a favorable state in the polymerization apparatus,
The rate at which the polymer of the desired composition is formed increases,
Since it is suppressed that foreign matter that does not melt even at 0 ° C. and enters the polymer is suppressed, the cycle of cleaning the inside of the can can be made longer than before. Here, the shear rate between the stirring blade and the can wall means a value obtained from the following equation.

Shear rate (1 / sec) = 2 × 2 × 3.14 ×
Stirring number (rotation / second) x can inner diameter x can inner diameter / (can inner diameter x can inner diameter-stirrer outer diameter x stirrer outer diameter) The mixing order is as follows: a part or all of liquid crystalline polyester raw material, powder raw material The slurry is preferably prepared in the following order: The temperature of the slurry adjusting tank is controlled to 120 ° C. or lower to suppress a reaction other than that desired, and to suppress the evaporation of the raw material, thereby obtaining a liquid crystal polyester having a desired composition. From the point of view, the lower limit is preferably 10 ° C. or higher. In particular, it is preferable to carry out in the range of 20 ° C to 50 ° C.

The solid content concentration of the slurry is 40 to 7
The mixture is adjusted to 0% by weight, preferably 50 to 65%, and stirred. In this case, it is preferable to charge the remaining liquid raw material to the polymerization apparatus while washing the slurry mixing tank after preparing the slurry. Here, the solid content concentration refers to a value determined by the following equation. Solid content concentration (wt%) = powder raw material weight / (powder raw material weight + liquid raw material weight) × 100% In addition, when the polymer of polyethylene terephthalate is used as a raw material in a non-powder form such as a pellet form containing the structural unit (III) It is preferable to supply the raw material directly to the raw material supply port in view of the dispersibility of the slurry.

The polymerization apparatus used in the present invention includes a reaction vessel having a raw material inlet, a stirring device, and a discharge port, and a condenser for condensing vapor distilled from the reaction vessel during the reaction.
A vertical reactor comprising a condensed liquid receiving tank and a vacuum generator at the time of polymerization under reduced pressure is preferably mentioned. The number of reactors may be one, but a device having two or more reactors is preferred. Further, a reactor having a shape in which the ratio of the length to width of the reactor is greater than 1 and less than 3 is preferred.

The reactor for producing the liquid crystal polyester is as described above, and when producing by the method (1), generally two or more reactors are used.

When an acylation reaction and deacetic acid polymerization are carried out using two reactors, usually a raw material which has been slurried in advance or a raw material which has been slurried and other raw materials are charged into the reactor 1 and the temperature is increased by 130 ° C. After acylation at 1 to 150 ° C for 1 hour, the temperature is further raised to 200 to 300 ° C to distill off the distillate produced by the acylation and the unreacted acylating agent. Next, transfer to the reaction vessel 2 with a vacuum generator,
Further, the temperature is raised to 250 ° C. to 400 ° C., and polycondensation is performed under reduced pressure and vacuum.

The method for producing the liquid crystal polyester of the present invention comprises:
One or more monomers selected from 6-hydroxy-2-naphthoic acid, aromatic diols, aromatic dicarboxylic acids, polyesters comprising ethylenedioxy units and aromatic dicarbonyl units, and p-hydroxybenzoic acid Is effective in the case of performing an acylation reaction and deacetic acid polymerization using an acylating agent such as acetic anhydride.

In particular, when a polyester comprising an ethylenedioxy unit and an aromatic dicarbonyl unit is used as a raw material for a liquid crystal polyester, p-hydroxybenzoic acid, aromatic diol, aromatic dicarboxylic acid, and the above polyester are used as raw materials. The effect is remarkable when producing a liquid crystal polyester, that is, when producing a liquid crystal polyester comprising the following structural units (I), (II), (III) and (IV).

[0040]

Embedded image (However, R1 in the formula is

Embedded image R1 represents one or more groups selected from

Embedded image And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom. The structural unit (I) is a structural unit generated from p-hydroxybenzoic acid, and the structural unit (II) is 4,4′-dihydroxybiphenyl, 3,3 ′, 5,5′-tetramethyl-4, 4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane and 4,4'-dihydroxydiphenyl ether The structural unit (III) is a structural unit generated from ethylene glycol, and the structural unit (IV) is a terephthalic acid, isophthalic acid, or 4,4'-diphenyldicarboxylic acid. , 2,6-Naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane -4,4'-dicarboxylic acid,
1,2-bis (2-chlorophenoxy) ethane-4,4
The structural units generated from aromatic dicarboxylic acids selected from '-dicarboxylic acid and diphenyl ether dicarboxylic acid are shown below.

Of these, R1 is

Embedded image Is at least 70 mol% of the structural unit (II)
But

Embedded image Is more preferably 70% or more of the structural unit (IV).

The above structural units (I), (II), (III),
The copolymerization amount of (IV) is optional. However, the following copolymerization amount is preferred from the viewpoint of fluidity.

That is, from the viewpoint of heat resistance, flame retardancy and mechanical properties, the sum of the structural units (I) and (II) is 60 to 95 mol% of the total of (I), (II) and (III). Is preferable, and 82 to 93 mol% is more preferable. The structural units (III) are represented by (I), (II) and (III)
Is preferably 40 to 5 mol%, more preferably 18 to 7 mol%. The molar ratio [(I) / (II)] of the structural units (I) and (II) is preferably 75/25 to 95/5, and more preferably 78 from the viewpoint of the balance between heat resistance and fluidity. / 22 to 93/7. The structural unit (I
V) is preferably substantially equimolar to the sum of the structural units (II) and (III).

The preferred liquid crystalline polyester is preferably produced by an acylation reaction and deacetic acid polymerization using a monomer capable of forming the above structural unit as a raw material capable of constituting the liquid crystalline polyester. In this case, using a liquid acylating agent such as acetic anhydride, a monomer capable of forming the structural unit (I) and a monomer capable of forming the structural unit (II) are substantially equimolar in amount. The monomer capable of forming (IV) is used as a powdery raw material, and the structural unit (III) and a polyester comprising the structural unit (IV) in a substantially equimolar amount with the structural unit (III) are used as a non-powder raw material such as a pellet. It is preferable in terms of the dispersibility of the slurry that the raw material in powder form and the acylating agent in liquid form are slurried, and the raw material and the non-powder raw material are fed into the raw material supply port of the polymerization apparatus.

In the polycondensation of the above-mentioned preferred polyester, 3,3'-diphenyldicarboxylic acid and 2,2'-polyester are used in addition to the components constituting the structural units (I) to (IV).
Aromatic dicarboxylic acids such as aromatic dicarboxylic acids such as diphenyldicarboxylic acid, adipic acid, azelaic acid, sebacic acid, dodecandioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone,
Aromatic diols such as methylhydroquinone, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl Aliphatic, alicyclic diols such as glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid; and p-amino Phenol, p
-Aminobenzoic acid and the like can be further copolymerized in such an amount as not to impair the liquid crystallinity.

Some liquid crystal polyesters produced according to the present invention can be measured for logarithmic viscosity in pentafluorophenol, in which case the concentration is 0.1 g / dl.
It is preferably 0.3 dl / g or more as measured at 0 ° C.
Particularly preferred is 0.5 to 3.0 dl / g.

The melt viscosity of the liquid crystal polyester in the present invention is preferably from 10 to 20,000 poise, more preferably from 20 to 10,000 poise.

The melt viscosity is calculated as melting point (Tm) +10
It is a value measured by Shimadzu Corporation flow tester CFT-500 under conditions of a shear rate of 1,000 (1 / second) under the condition of ° C.

Here, the melting point (Tm) is defined as the difference between room temperature and 20 ° C.
After observing the endothermic peak temperature (Tm1) observed when the temperature was measured under the temperature rising condition for 5 minutes, the temperature was maintained at a temperature of Tm1 + 20 ° C. for 5 minutes, and then cooled once to room temperature under the cooling condition of 20 ° C./min. It refers to the endothermic peak temperature (Tm2) observed when the temperature is measured again at a temperature rising condition of 20 ° C./min.

[0050]

The present invention will be described in more detail with reference to the following examples.

Example 1 200 ml of acetic anhydride was placed in a slurry mixing tank having an inner volume of 1.5 m ³ , an inner diameter of the can of 1.2 m, and a distance between the inner wall surface of the can and the stirrer of 2 cm.
After stirring, the inside of the can was stirred at 30 rpm for 5 minutes, then increased to 80 rpm, and 220 kg of p-hydroxybenzoic acid (average particle size of 0.3 mm or less), 4,4′-
Dihydroxybiphenyl (average particle diameter 0.3 mm or less)
27.8 kg and terephthalic acid (average particle diameter 0.3 mm
The following) 24.8 kg was charged. Thereafter, the temperature in the slurry tank was kept at 25 ° C. to 35 ° C., and stirring was continued for 30 minutes. Then, the whole amount was charged into a reaction vessel 1 having the following shape, and 11.8 kg of acetic anhydride was further charged into the slurry mixing tank in a spray form. The inside of the tank was washed, and the washing liquid was charged into the reaction vessel 1. At this time, the shear rate between the slurry tank stirring blade and the can wall was 255.
(1 / sec). Internal volume 1.6 m ³ , inner diameter of can 1.
2 m, a reaction vessel 1 having a distance of 1 cm between the inner wall surface of the can and the stirrer and a reaction vessel 2 having an inner volume of 0.8 m ³ and an inner diameter of 1.1 m of the can having a distance of 2 cm between the inner wall surface of the can and the stirring blade. And polymerized as follows.

After charging the slurry, the reactor 1 was stirred for 3 minutes.
47.8 kg of pelleted polyethylene terephthalate was charged while performing the rotation at 0 rpm, and the temperature was raised. At the same time, the temperature was increased to 60 rpm, and the temperature in the can was reduced to 1 in 0.75 hours.
After the temperature reached 40 ° C., the temperature of the reaction vessel 1 was raised from 140 ° C. to 250 ° C. over 3.5 hours after the reaction at 140 ° C. for 1 hour to bring the temperature in the vessel to 250 ° C. After that, move to reactor 2
The stirring rate is 25 rpm over 3 hours while stirring at 30 rpm.
The temperature was reduced from 0 ° C. to 320 ° C., the pressure in the polymerization vessel was reduced to 1 Torr, and stirring was continued at 320 ° C. for 0.5 hour to complete the polycondensation reaction. Then, after pressurizing the inside of the reaction can 2 to 1 kg / cm ² , the polymer was discharged in the form of a strand via a die and formed into pellets. The theoretical structural formula of this polymer is shown below.

[0053]

Embedded image k / l / m / n = 80 / 7.5 / 12.5 / 20 When the polymer of the above composition is repeatedly batch-polymerized by the above-mentioned method, it is mixed with the discharged polymer after the polymerization and becomes a foreign substance. Did not occur until the 40th batch, and repeated polymerization was possible for a long period of time.

Comparative Example 1 The same raw material and the same amount as in Example 1 were directly charged into the reaction vessel 1 without using the slurry mixing tank, and the batch polymerization was repeated under the same conditions. As a result, a phenomenon of becoming a foreign substance by mixing into the discharged polymer after the completion of the polymerization appeared, so that the polymerization was repeatedly interrupted and the inside of the can was washed.

Comparative Example 2 In the same manner as in Comparative Example 1, the raw materials were directly charged into the reactor 1 without using a slurry tank, and the same conditions as in Example 1 were repeated except that the stirring speed of the reactor 1 was changed to 20 revolutions / minute. The batch polymerization resulted in a composition which did not melt even at 350 ° C. at the 10th batch, and a phenomenon in which it was mixed in the discharged polymer after polymerization and became a foreign substance appeared. Therefore, the polymerization was repeatedly interrupted and the inside of the can was washed.

The shear rate at the stirring blade and the wall surface of the reactor by stirring the reactor 1 at 20 revolutions / minute was 127 (1 / sec).

As described above, it can be seen that the examples of the present invention have higher continuous batch properties than the comparative examples.

[0058]

According to the present invention, the productivity of liquid crystal polyester is improved, and a high quality polymer having excellent heat resistance can be obtained.

Claims (8)

[Claims] 1. A liquid crystalline polyester raw material containing a powdery liquid crystalline polyester raw material and a liquid are charged from a raw material inlet of a polymerization apparatus and heated and polycondensed to produce a liquid crystalline polyester. Is prepared in a slurry state and then charged into a raw material charging port. 2. The method for producing a liquid crystal polyester according to claim 1, wherein the polymerization of the liquid crystal polyester includes an acylation reaction using an acylating agent and a deacetic acid reaction. 3. The method for producing a liquid crystal polyester according to claim 1, wherein the liquid is acetic anhydride used as an acylating agent. 4. The process for producing a liquid crystal polyester according to claim 1, wherein the powdery liquid crystal polyester raw material is at least one selected from aromatic oxycarboxylic acids, aromatic diols and aromatic dicarboxylic acids. 5. The method for producing a liquid crystal polyester according to claim 1, wherein the liquid crystal polyester raw material contains a polyester obtained by polycondensing an ethylenedioxy unit and an aromatic dicarbonyl unit. . 6. A powdery liquid crystalline polyester raw material and a liquid
The method for producing a liquid crystal polyester according to any one of claims 1 to 5, wherein the slurry is adjusted to a slurry state by stirring in a range of 0 ° C to 120 ° C. 7. A slurry is formed by using a slurry adjusting tank so that a stirring condition in the slurry adjusting tank is such that a shear rate between a stirring blade and a wall surface of the tank is 150 to 1000 (1 / second). The method for producing a liquid crystal polyester according to any one of claims 1 to 6, wherein the method is performed. 8. The liquid crystal polyester according to the following (I), (II),
The method for producing a liquid crystal polyester according to any one of claims 1 to 7, wherein the method is a liquid crystal polyester comprising the structural units (III) and (IV). Embedded image (However, R1 in the formula is Wherein R2 represents one or more groups selected from And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom. )