JPS6284116A - Production of polyarylate - Google Patents

Abstract

PURPOSE:To economically produce a polyarylate having improved heat resistance with good operability, by polymerizing an aromatic diol with a dicarboxylic acid and anhydrous aliphatic carboxylic acid under such conditions that melt viscosity and vacuum degree may satisfy a specific formula. CONSTITUTION:(A) An aromatic diol expressed by formula I (R is 1-10C alkylene; n is 0 or 1) or formula II, e.g. 4,4'-(dihydroxyphenyl)sulfone, (B) an aromatic dicarboxylic acid, e.g. terephthalic acid, and (C) a 1-8C anhydrous aliphatic dicarboxylic acid, e.g. acetic anhydride, are charged into, e.g. a vacuum type twin-screw kneader at 1:0.8:1-1:1.2:10 molar ratio of the components (A):(B):(C) and polymerization is started at 100-160 deg.C under ordinary pressure. The polymerization is carried out under such conditions that vacuum degree is <=0.08 Torr in the course thereof and the product of the vacuum degree x melt viscosity (poise) is <=500 to afford the aimed polyarylate.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing polyarylate having excellent heat resistance, and further relates to a method for producing polyarylate which is obtained from an aromatic diol and an aromatic dicarboxylic acid. The present invention relates to a method for producing polyarylate with excellent heat resistance economically and with good operability.

(Prior Art) Fully aromatic polyarylate has been known as a heat-resistant polymer. For example, 4-hydroxybenzoic acid homopolymer or 4-hydroxybenzoic acid copolymer (for example, Sumitomo Chemical's product name Econol), or 2,2-bis(4-hydroxyphenyl)furopane (bisphenol A; hereinafter referred to as BA)
) and terephthalic acid (hereinafter abbreviated as TPA)
A polymer (for example, Unitika's trade name U polymer) consisting of isophthalic acid and isophthalic acid (hereinafter abbreviated as IPA) was once proposed, and is now also used as a top fabric.

In particular, for the latter polyarylate, many manufacturing methods have been described in the literature, and they are essentially divided into three methods. Namely, (1) an acid halide method in which an alkali metal salt of an aromatic diol and an aromatic dicarboxylic acid civalide are brought into liquid-liquid contact as a solution, and react in the solution or at the interface between the two phases; (2) an aromatic halide method; (3) A method in which an aromatic diol is reacted with a diaryl ester of an aromatic dicarboxylic acid.

The present inventors proposed a method in which a polyarylate prepolymer is first molded into an appropriate shape, and then the prepolymer is solid-phase polymerized under reduced pressure and at specific temperature conditions (Japanese patent application No. 5
No. 9-177650, No. 60-51940).

(Problems to be solved by the invention) However, since the method (1) above inevitably uses an expensive solvent, it is not only uneconomical but also requires steps for separating and purifying the product. There are drawbacks such as.

On the other hand, the methods (2) and (3) above (for example, U.S. Patent No. 4,485,230 Saimei 7IB and JP-A-60-5
3527, etc.), the melt viscosity rapidly increases as the degree of polymerization of polyarylate increases, making it difficult to obtain polyarylate with a high degree of polymerization. Therefore,
First, a method was adopted in which a prepolymer was produced, then the prepolymer was pulverized into a fine powder, and then subjected to solid phase polymerization (for example, in contrast to method (2), U.S. Patent No. 3
, 684.766, U.S. Pat. No. 3,780.1
48 specification, etc.).

This method has the disadvantage that it is necessary to bring the prepolymer into contact with a crystallizing agent to crystallize the polymer, making the process complicated.

Furthermore, Japanese Patent Application Laid-Open No. 57-2331 proposes the following proposal in order to omit this crystallization step. That is, a manufacturing method is disclosed in which a solvent such as diphenyl ether is coexisting in the first step of manufacturing a prepolymer.

Although the crystallization step can be omitted in such a method, there is a risk that the good physical properties inherent to the polymer may be impaired.

Furthermore, two methods previously proposed by the present inventors (Japanese Patent Application No. 1983-
177650, 60-51940),
However, in order to produce a polyarylate with a high degree of polymerization, there is a drawback that it is necessary to further polycondense the prepolymer for usually about 10 hours or more.

On the other hand, the present inventors separately proposed a method of producing polyarylate with a high degree of polymerization by melt polymerizing while kneading using a vacuum twin-screw kneader (Japanese Patent Application No. 59-257195
issue).

However, even when such a method is used.

Most polyarylates have an abnormally high melt viscosity, and in that case, a sufficient overall mass transfer rate may not be obtained, making it extremely difficult to produce polyarylates with a high degree of polymerization. Understood.

Despite the excellent properties of polyarylates obtained from aromatic diols and aromatic dicarboxylic acids, the method for producing polyarylates economically and with good operability has not been fully developed industrially. It could not be said that it had been done.

(Means for Solving the Problems) The main object of the present invention is to provide an economical and easily operable method for producing heat-resistant polyarylates with a high degree of polymerization, which are particularly suitable for plasma spray coatings and molded products used at high temperatures. This is what we provide.

In order to achieve the above object, the present inventors have conducted intensive research on a method for producing heat-resistant polyarylate, and as a result, we have found that aromatic diol, aromatic dicarboxylic acid, and aliphatic carboxylic anhydride (hereinafter abbreviated as AA) are used as raw materials. We have found that melt polymerization under specific reduced pressure conditions is a manufacturing method with extremely excellent operability and economy, and have thus arrived at the present invention.

The present invention has the following configuration. That is, the following structural formula (I
) or (II), at least one aromatic dicarboxylic acid, and an aliphatic carboxylic anhydride having 1 to 8 carbon atoms. ≦0.
The gist of the present invention is a method for molding polyarylate, which is characterized by performing melt polymerization under conditions such that μ×ν≦500 and μ×ν≦500. (Here, μ is the melt viscosity (poise) of polyarylate at the polymerization temperature, and ν is the degree of vacuum (to
rr) are shown respectively. ) (wherein R is an alkylene group having 1 to 10 carbon atoms, an alkylidene group having 1 to 10 carbon atoms, and an arylene group having 1 to 10 carbon atoms.

Cycloalkylene group having 1 to 10 carbon atoms.

a cycloalkylide group having 1 to 10 carbon atoms,
It represents a group selected from O, S, SO, SO2 and CO, and n is 0 or 1. Note that the hydrogen atom of the phenylene group may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an alkoxy group. ) (The hydrogen atom of the phenylene group may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an alkoxy group.) Also, particularly preferably, the hydrogen atom of the phenylene group is represented by the formula (1) The aromatic diol is a compound represented by the following formula (1) or (V).

The aromatic diol represented by the formula (II) is a compound represented by the following formula (V), and the aromatic dicarboxylic acid is TP
The gist of the present invention is a method for producing polyarylate, which is A and/or IPA, and is further kneaded under conditions such that P/V≧0.1 using a vacuum twin-screw kneader as a reaction device.

CH3 CH3 The average degree of polymerization (Pn) of the heat-resistant polyarylate produced by the method of the present invention is generally 40-300°, preferably 50-200°. The optimum range is 65 to 150. When Pn is smaller than this range, there are various physical and mechanical properties including the heat resistance mentioned above.

On the other hand, if Pn is larger than this range, the melt viscosity will be too high, impairing fluidity, or the melting point will be too high, resulting in high molding and temperature, both of which are undesirable. do not have.

In the first step of the method for producing heat-resistant polyarylate, a prepolymer is produced using aromatic diol, aromatic dicarboxylic acid, and AA as raw materials. At this time, the aromatic diol and the acid anhydride may be reacted in advance and then reacted with the aromatic dicarboxylic acid, but it is preferable to allow the diol to coexist and react directly, in order to shorten the process.

Examples of the aromatic dicarboxylic acid referred to in the present invention are:

TPA, IPA, 4,4-dicarboxybiphenyl.

Examples include bis(4-carboxyphenyl)methane, 2,2-bis(2-carboxyphenyl)propane, bis(4-carboxyphenyl)sulfone, bis(2-carboxyphenyl)ether, and 7-talic acid. Note that, if necessary, a mixture of the aromatic dicarboxylic acids may be used, and a mixture of TPA and IPA is particularly preferably used.

On the other hand, the aromatic diol referred to in the present invention is a compound having the general formula shown in (1) or (II) above. Specifically, BA represented by the above formulas (1), (IV), and (V), 4゜4'-(dihydroxyphenyl)sulfone (
Bisphenol S (hereinafter referred to as BS), 9. ], ]
O-dihydro-9-oxer-10(2', dihydroxyphenyl)-phosphaphenanthrene-10-oxide (hereinafter abbreviated as PHQ) is particularly preferably used; -tpn, bis-(4-hydroxyphenyl)-methane, bis-
(4-Hydroxy-2,6-dimethyl-3-methoxyphenyl)-methane, 1°1-bis-(4-hydroxyphenyl)-methane.

1.1-bis-(4-hydroxy-2-chlorophenyl)-ethane, 1.3-bis-(3-methyl-4-hydroxy7enyl)-furopane, 2.2'-bis-(3- 1
nprovir-4-hydroxyphenyl)-furopane, 4
．． 4'-(dihydroxyphenyl)-ether, 2.2
'-bis-(4-hydroxyphenyl)-pentane, 3
．． 3'-bis-(4-hydroxyphenyl)-pentane, 2.2'-bis-(4-hydroxyphenyl)-hebutane, 4.4'-(dihydroxyphenyl)-sulfide, 4.4'-(dihydro coconut phenyl)-sulfoxide, 4,4'-(dihydroxyphenyl)-sulfone,
4.4'-(dihydroxybenzophenone) etc. can also be used.

In addition, in the present invention, resorcinol, hydroquinone, etc. can also be used, and furthermore, 4-hydroxybenzoic acid,
Aromatic oxycarboxylic acids such as 2-hydroxy-6-naphthoic acid may be copolymerized in an amount not exceeding 30 mol.

PHQ used in the present invention is expressed by the following formula (9 represented by VD,
It can be produced by reacting 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and benzoquinone in a suitable solvent such as ethyl cellosolve (see JP-A-60-126293).

The aliphatic carboxylic anhydride (AA) referred to in the present invention is.

Acid anhydrides of lower fatty acids having 1 to 8 carbon atoms, such as acetic anhydride, chloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, bromoacetic anhydride, glutaric anhydride, maleic anhydride, conolilic anhydride, β anhydride - Bromopropionic acid, propionic anhydride.

Examples include butyric anhydride, isobutyric anhydride, propyl acetic anhydride, and acetic anhydride is particularly preferred. When the number of carbon atoms exceeds 8, the boiling point of the acid anhydride becomes too high.

O is unfavorable because the reaction rate in the polycondensation step decreases.In the first step of producing polyarylate mentioned above, when producing a polyarylate prepolymer, an aromatic diol, an aromatic dicarboxylic acid, and an acid anhydride are used. The molar ratio at the time of preparation is usually 1: 0.8: 1 to 1: 1.2.
:10. Preferably 1:0.9:2-1:
1.1:4. The optimum ratio is 1:1:2.

Further, in the present invention, an esterification reaction, a transesterification reaction, and a type 1 condensation reaction are involved. A catalyst is usually used to promote each of these reactions, and it is preferable to use, for example, one or more compounds selected from various metal compounds or organic sulfonic acid compounds. Such metal compounds include antimony, titanium, germanium,
Tin.

Zinc, aluminum, magnesium, calcium.

Compounds such as manganese and cobalt are used.

On the other hand, as the organic sulfonic acid compound, compounds such as sulfosalicyl Mt and o-sulfobenzoic anhydride (hereinafter abbreviated as O8B) are used, but dimethyl tin maleate (hereinafter abbreviated as C8) is particularly preferably used. It will be done. The amount of the catalyst added is as follows.

Usually 0.0% per mole of polyarylate structural unit. lXl
0 to Zoo X 10 mol, preferably 0.5 X
10-' to 50 x 10 moles, optimally 1 x 10
~10 x 10 moles are used.

In the second step of producing heat-resistant polyarylate, the prepolymer obtained in the first step is melt-polymerized under the conditions specified in the present invention. ≦O, OS, and μ×ν≦500
If the reaction is not carried out, polyarylate with a high degree of polymerization cannot be produced economically and with good operability.

According to the common knowledge of the prior art, even though it is called "full depressurization", the depressurization conditions actually applied to polyarylate polymerization due to equipment restrictions are about 0.1 torr at most,
The melt viscosity of the obtained polyarylate with a high degree of polymerization is usually tens of thousands of poise or more, so μ×ν is usually 5,000.
If the melt polymerization is carried out by heating under such conditions, the overall mass transfer rate will drop significantly as the degree of polymerization increases, and the reaction will essentially stop at a certain degree of polymerization. As a result, polyarylate with a high degree of polymerization cannot be produced at a practical rate.

As described above, in the melt polymerization according to the present invention, it is not only necessary to simply perform polycondensation under high vacuum, but also to specify the reduced pressure conditions depending on the melt viscosity. That is, in the method of the present invention, it is necessary to create a vacuum as high as would be unimaginable based on conventional technical common sense.

In addition, it is particularly preferable to use a vacuum type twin-screw kneader with a large kneading capacity as one reaction device.If a vacuum-type twin-screw kneader is not used, the diffusion rate of one reactive species or volatile product will be reduced. This may result in a decrease in the so-called overall mass transfer rate, which may be undesirable.

In addition, in the present invention, a suitable reactor to be used is, for example, a high-torque, reduced-pressure, two-shaft cross-wire type device with a devised leakage mechanism at the shaft seal, as in Utility Application No. 60-56218. It is.

Next, the method for producing polyarylate will be explained in detail in the order of steps.

In the first stage of polyarylate production, 1 usually under normal pressure and at a temperature below the boiling point of the above-mentioned AA 1 usually 300 to 16
1-8 hours at 0°C, preferably 2-8 hours at 20-160°C
6 hours, optimally at 140-160°C for 2-5 hours, then usually under reduced pressure (10-500 torr), and finally at 150-300°C for 1-8 hours, preferably 2 hours.
00-280℃ for 2-6 hours, optimally 260-280℃
React for 2-5 hours at <0>C. Like this K1. When the reaction is carried out, a polyarylate prepolymer having an average degree of polymerization of about 20 is obtained in the first step of polyarylate production.

Next, in the second stage of polyarylate production, the obtained polyarylate prepolymer is kept in a molten state and further subjected to one specific reduced pressure condition referred to in the present invention.

That is, finally ν≦008. The prepolymer is heated at 280 to 400°C, preferably 280°C or 350°C, and optimally 300 to 340°C under the conditions that μ×ν≦500.

A polyarylate having a high degree of polymerization can be produced by performing melt polymerization for usually 0.1 to 10 hours, preferably 1 to 5 hours, and optimally 2 to 4 hours.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, the average degree of polymerization of the polymer in one example was determined by gel permeation chromatography (Toyo'[iHJ[I(LC8
The molecular weight was determined by dividing the number average molecular weight measured at a temperature of 39°C using chloroform containing 2.5 mo of 1% hexafluoroisopropanol as a solvent by the molecular weight of the repeating unit. In addition, the glass transition temperature and melting point were measured using a differential calorimeter (PerkinElmer D
SC-2 type) was used to measure the temperature at a temperature increase rate of 20°C/min.

On the other hand, the melt viscosity of the polyarylate according to the present invention is KOK
A type A flow tester (CFT-500 model manufactured by Shimadzu Corporation) was used.

It was determined by separately measuring sampled polyarylate.

Example 1 A reaction device (vacuum type twin-screw kneader) was charged with BA and acetic anhydride in a molar ratio of 1:2 and IPA in an equimolar amount with BA, and C8 was added as a catalyst at a ratio of 4 to 1 mole of polyarylate structural unit.
X10 moles were added, and the mixture was reacted under nitrogen atmosphere at normal pressure at 150°C for 2 hours with mixing.

This reaction product was further heated at 250°C under normal pressure for 2 hours, and further heated for 5 hours.
The reaction was carried out at 260° C. for 4 hours at 0 tOrr.

The reactants sampled had an average type-height of 17.

The temperature of the reaction mixture was gradually raised over 1 hour.

The reaction was carried out under reduced pressure, and the temperature was finally raised to 325° C., and the degree of vacuum was adjusted to 0.02 torr.

Melt polymerization was carried out at P/V = 0.7 (kw/Kq) for a total of 3 hours.

The obtained polyarylate had a melt viscosity of 11,000 poise at 325°C and a final μ×ν of 220. Moreover, this polyarylate has an average degree of polymerization of 87. It was an amorphous polymer with a glass transition point of 185°C and excellent color tone and transparency.

Example 2 Into the reaction apparatus used in Example 1, BS and acetic anhydride were charged in a molar ratio of 1=2 and IPA in the same mole as BS, and 1 mole of dimethyl tin maleate (C8) polyallylate structural unit was added as a catalyst. 3 x 10-' mol was added to the mixture, and the mixture was reacted under a nitrogen atmosphere at normal pressure of 150°C with stirring for 2 hours. This reaction product was further heated at 250 °C under normal pressure for 2 hours, and then heated at 250 °C for 50
The reaction was carried out at 260° C. for 4 hours at tOrr. The sampled reaction product had an average degree of polymerization of 18.

The temperature of the reaction mixture was gradually raised over 1 hour.

The reaction was carried out under reduced pressure, and the temperature was finally raised to 330°C, and the degree of vacuum was adjusted to 0.03 torr.

Melt polymerization was carried out for a total of 5 hours at P/V = 0.6 (kW Otsu 7).

The obtained polyarylate has a melt viscosity of 9,900 poise at 330°C, and the final μ×ν is 29
It was 7. Moreover, this polyarylate has an average degree of polymerization of 71. It was an amorphous polymer with a glass transition point of 191° C. and excellent color tone and surface transparency.

Example 3 PHQ shown by the above formula (II) was produced by reacting the phosphinic acid shown by the above formula (to) with p-benzoquinone at a temperature of 90° C. in an ethylseronup solvent. The obtained PHQ and acetic anhydride were charged into the reaction apparatus used in Example 1 at a molar ratio of 1:4.

Add 3X10 moles of O3B as a catalyst to 1 mole of the structural unit of polyarylate at 150°C under nitrogen atmosphere at normal pressure.
The mixture was reacted with stirring for 2 hours to synthesize diacetate of PHQ.

Equimolar TPA/IPA (1
/1 molar ratio) was further reacted at 270C under normal pressure for 2 hours, and further reacted at 100 torr and 270C for 2.5 hours. This reaction product had an average degree of polymerization of 19.

The temperature of the reaction mixture was gradually raised over 1 hour.

The reaction was carried out under reduced pressure, and the temperature was finally raised to 340°C, and the degree of vacuum was adjusted to 0.01 torr.

Melt polymerization was carried out at P/V = 1.1 (kw/Kg) for a total of 6 hours.

The obtained polyarylate has a melt viscosity of 38,000 poise at 340°C and a final μx v
It was tp380. Moreover, this polyarylate has an average degree of polymerization of 69. It was an amorphous polymer with a glass transition point of 222°C and excellent color tone and transparency.

Example 4 PHQ obtained in Example 3 was added to the reactor used in Example 1.
and BA (3/1 molar ratio) and acetic anhydride in a 1:3 molar ratio, and 3×10-' mol of O8B was added as a catalyst per 1 mol of the structural unit of polyarylate, and the mixture was heated at 150°C under nitrogen atmosphere at normal pressure for 2 hours. React with mixing, PHQ and B
Diacetate of A was synthesized.

Equivalent moles of TPA/IPA (3/1 molar ratio) to the total number of moles of this reactant, PHQ, and BA were further added at 270 °C under normal pressure.
React at ℃ for 2 hours and further at 100 torr.

The reaction was carried out at 270°C for 2.5 hours. This reaction product had an average degree of polymerization of 14.

The temperature of the reaction mixture was gradually raised over 1 hour.

The reaction was carried out under reduced pressure, and the temperature was finally raised to 340°C, and the degree of vacuum was adjusted to 0.02 torr.

Melt polymerization was performed for a total of 5 hours at P/V = 1.0 (kw/Kq).

The obtained polyarylate has a melt viscosity of 18.0OOpoise at 340°C, and the final μ×ν is 3
It was 60. Moreover, this polyarylate has a 1,000' homogeneous polymerization degree of 69. It was an amorphous polymer with a glass transition point of 215°C and excellent color tone and transparency.

Example 5 The reaction apparatus used in Example 1 was charged with resorcinol (R8) and acetic anhydride in a molar ratio of 1:2 and TPA in an equimolar amount with R8, and dimethyltin maleate (C8) was used as a catalyst to form a polyarylate. 2×10 3 moles were added per 1 mole of units, and the mixture was reacted with stirring at 150° C. under a nitrogen atmosphere for 2 hours at normal pressure. This reaction product was further reacted at 250° C. for 2 hours under normal pressure, and then at 260° C. for 4 hours at 50 torr. This sampled reactant has an average degree of polymerization of 2
It was 1.

The temperature of the reaction mixture was gradually raised over 1 hour.

The reaction was carried out under reduced pressure, and the temperature was finally raised to 320°C, and the degree of vacuum was adjusted to 0.05 torr.

Melt polymerization was carried out for a total of 5 hours at P'/V = 0.5 (kW Otsu 7).

The obtained polyarylate has a melt viscosity of 8900 poise at 320°C, and the final μ×ν is 49
It was 5. Moreover, this polyarylate has an average degree of polymerization of 5
4. It was an amorphous polymer with a glass transition point of 156°C and excellent color tone and transparency.

Comparative Example 1 A polyarylate prepolymer having an average degree of polymerization of 17 was obtained in the same manner as in Example 1.

The reactant was left in the dark for 1 hour, and the reaction was carried out by successively increasing the temperature and reducing the pressure, and the temperature was finally raised to 325°C.

Adjust the degree of vacuum to 0.10 torr, and
/V=o, o 5 (kwAg) and melt polymerization was carried out for a total of 10 hours. The obtained polyarylate had a melt viscosity of 5,500 poise at 325°C, and a final μ×ν of 550. Further, this polyarylate was an amorphous polymer with an average degree of polymerization of 37, a glass transition point of 183° C., 9 color tones, and excellent transparency.

(Effects of the Invention) According to the present invention, (1) Since no solvent is used, there is no need to separate or generate prepolymers or polymers.

(2) Since no expensive solvent is used, polyarylate can be produced economically; (3) Since the polyarylate prepolymer is discharged in a molten state, processing is simple.

A polyarylate having excellent physical properties as a heat-resistant polymer, such as extremely good operability, can be obtained economically and with good operability. In addition, the polyarylate obtained by the present invention is extremely useful as a material for films, textiles, and molded products used in applications requiring particularly heat resistance.

Claims (6)

[Claims] (1) When producing a polyarylate from at least one aromatic diol represented by the following structural formula (I) or (II), at least one aromatic dicarboxylic acid, and an aliphatic carboxylic anhydride having 1 to 8 carbon atoms, A method for producing polyarylate, characterized in that in at least a part of the polymerization step, melt polymerization is carried out under conditions such that ν≦0.08 and μ×ν≦500. (Here, μ indicates the melt viscosity (poise) at the polymerization temperature of polyarylate, and ν indicates the degree of vacuum (torr).) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R is Alkylene group having 1 to 10 carbon atoms, alkylidene group having 1 to 10 carbon atoms, arylene group having 1 to 10 carbon atoms, 1 to 10 carbon atoms
Cycloalkylene group having 1 to 10 carbon atoms, cycloalkylidene group having 1 to 10 carbon atoms, O, S, SO, SO_2
and CO, and n is 0 or 1. Note that the hydrogen atom of the phenylene group may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an alkoxy group. ) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (II) (The hydrogen atom of the phenylene group may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an alkoxy group. ) (2) The aromatic diol represented by formula (I) is expressed by the following formula (
The method for producing a polyarylate according to claim 1, which is a compound represented by II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (3) The aromatic diol represented by formula (I) is expressed by the following formula (
A method for producing a polyarylate according to claim 1, which is a compound represented by IV). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(IV) (4) The aromatic diol represented by formula (II) is the following formula (V
) The method for producing polyarylate according to claim 1, which is a compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(V) (5) The method for producing a polyarylate according to any one of claims 1 to 4, wherein the aromatic dicarboxylic acid is isophthalic acid and/or terephthalic acid. (6) In the step of producing polyarylate, a vacuum twin-screw kneader is used as a reaction device, and kneading is carried out under conditions such that P/V≧0.1. Method for producing polyarylate. (Here, P
represents the net stirring power (kw), and V represents the weight (kg) of the polyarylate. )