JP2001206940A - Method for producing wholly aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for economically producing a high-quality amorphous wholly aromatic polyester using a specific aromatic dicarboxylic acid as the acid component and using bisphenols as the aromatic diol component in good productivity. SOLUTION: When producing an amorphous wholly aromatic polyester by carrying out heat melt reaction of an aromatic dicarboxylic acid with bisphenols in the presence of diarylcarbonate, (1) a preliminary polymerization step for obtaining a prepolymer by reacting a mixed dicarboxylic acid containing terephthalic acid and isophthalic acid at a specific molar ratio with bisphenols in the presence of a diarylcarbonate, especially a specific catalyst, (2) a crystallization step for crystallizing the prepolymer and (3) a solid phase polymerization for increasing polymerization degree by heating the crystallized prepolymer under specific conditions are practiced in this order to inexpensively produce the objective amorphous wholly aromatic polyester having high polymerization and >=0.6 dl/g reduced viscosity in good productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing wholly aromatic polyester. More specifically, the present invention relates to a method for producing a wholly aromatic polyester having an excellent color tone and a high degree of polymerization from a specific aromatic dicarboxylic acid, aromatic diol and diaryl carbonate by combining prepolymerization and solid-phase polymerization with high productivity. .

[0002]

2. Description of the Related Art In recent years, performance requirements for engineering plastics having high heat resistance and excellent mechanical strength have been increasing. Amorphous engineering plastics include wholly aromatic polyesters and wholly aromatic polyester carbonates derived from aromatic diols and aromatic dicarboxylic acids. For example, 2,2-bis (4-
Hydroxyphenyl) propane and amorphous wholly aromatic polyesters comprising terephthalic acid and isophthalic acid as aromatic dicarboxylic acids have relatively balanced properties and are used for various applications.

[0003] Various studies have been made on the methods for producing these amorphous wholly aromatic polyesters. Among them, an acid halide of an aromatic dicarboxylic acid (hereinafter abbreviated as dicarboxylic acid) and an aromatic diol (hereinafter referred to as dicarboxylic acid) are disclosed. (Hereinafter, abbreviated as diol) has been industrialized. However, methylene chloride, which is usually used as a reaction solvent in this interfacial polycondensation method, is a chemical substance having environmental and sanitary problems, and its handling requires careful attention. Due to the extremely low temperature of 0 ° C., it is difficult and expensive to obtain a closed system in which the methylene chloride used in the production of the wholly aromatic polyester can be completely recycled.

[0004] Similarly, when a wholly aromatic polyester carbonate is produced from an acid halide of a dicarboxylic acid, a diol, and phosgene by an interfacial polymerization method, the same problem occurs. Therefore, a melt polymerization method of these polymers is being studied.

However, it is not practical to obtain these polymers by direct melt polymerization using dicarboxylic acids and diols as raw materials, because the coloring is severe and the polymerization rate is low. Therefore, in practice, a method (1) in which a diaryl ester of a dicarboxylic acid component is reacted with a diol in advance, a method (2) in which a dicarboxylic acid is reacted with a lower aliphatic carboxylic acid ester of a diol, and other methods of the above method (2) Method of adding lower aliphatic carboxylic acid anhydride when reacting dicarboxylic acid and diol (3)
Is used. However, these methods (1) and (2)
In such a case, the raw material must be esterified in advance, which causes high cost. In addition, these methods (2)
In (3), the lower aliphatic carboxylic acid is generated during the reaction, so that the apparatus is easily corroded, and the obtained polymer has a terminal COO.
There is a problem that the H group concentration is large.

As a method for solving such a problem,
There is a method in which a dicarboxylic acid, a diol, and a diaryl carbonate are heated and melted. But even with this method,
It was difficult to obtain a polymer having an excellent hue.

As a method for improving the hue of a polymer, for example, JP-A-3-128926 discloses a dicarboxylic acid and a diol using a borane-tertiary amine complex compound and / or a quaternary ammonium borohydride compound as a catalyst. A method for producing a wholly aromatic polyester by reacting a diaryl carbonate with a diaryl carbonate has been proposed. Japanese Patent Application Laid-Open No. 4-236224 proposes a method for producing wholly aromatic polyester using a specific tin compound as a catalyst.

However, aromatic dicarboxylic acids generally have low solubility, and dissolution of the dicarboxylic acid component is rate-determining.
Since the reaction must be performed at a high temperature and may require a long time, there is a limit in improving the polymer hue. Further, the conventional melt polymerization method has a problem that sublimates are generated during the polymerization reaction, the production process is complicated to remove them, and the equipment becomes large-scale, resulting in an increase in cost.

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, as previously proposed in Japanese Patent Application Laid-Open No. Hei 7-133345, show that an aromatic dicarboxylic acid and an aromatic dicarboxylic acid are present in the presence of a specific pyridine compound. It has been found that, when a diol is reacted with a diaryl carbonate, the resulting aromatic polyester is excellent in hue and the amount of sublimates during the polymerization reaction is reduced.

However, recently, with the improvement in required characteristics, a wholly aromatic polyester having a higher degree of polymerization has been desired. However, since the wholly aromatic polyester generally has a high melt viscosity, stirring during melt polymerization becomes difficult, and the degree of polymerization of the obtained wholly aromatic polyester is limited.

In general, solid-state polymerization is known as a method for solving this problem and obtaining a polymer having a high degree of polymerization. The solid phase polymerization method is a method in which a prepolymer having a certain degree of polymerization is synthesized by melt polymerization, crystallized by a heat treatment, a solvent treatment, or the like, and then the polymerization is continued in a solid phase. The solid state polymerization of wholly aromatic polyesters is described, for example, in US Pat. Nos. 3,684,766 and 3,728,416;
-35796, 53-43797, 53-54
No. 295, No. 59-21888, JP-A-5-3312
Nos. 70, 5-331271 and 8-319346.

However, US Pat. No. 3,684,766.
The method described in JP-A-5-331271 is a method in which a dicarboxylic acid is reacted with a lower aliphatic carboxylic acid ester of a diol. As described above, a method in which the raw material monomer is esterified in advance is used. The problem of high cost and the problem that the apparatus is liable to corrode and the obtained polymer has a high terminal COOH group concentration have not been solved.

Japanese Patent Application Laid-Open Nos. 53-35796 and 53-53
-43797, 53-54295, 59-21
888 or JP-A-5-331270, 8-
No. 319,346 describes a method of substantially reacting a diaryl ester of a dicarboxylic acid component with a diol, but these methods still have a problem of high cost due to esterification of a raw material. Further, U.S. Pat. No. 3,728,416 is a method for blending a prepolymer prepared in advance with a composition that is easy to crystallize, and has a problem that the production process is complicated and the cost is increased as a result.

As described above, it has been substantially difficult to obtain a high-molecular-weight polymer at low cost by the conventionally known method for producing a wholly aromatic polyester.

[0015]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method for preparing a high molecular weight amorphous wholly aromatic polyester having excellent heat resistance and mechanical properties without directly esterifying a dicarboxylic acid or a diol. It is an object of the present invention to provide a method for industrially and inexpensively producing a high molecular weight amorphous wholly aromatic polyester which can be produced from a diol and has excellent hue and good physical properties. .

[0016]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and has the following formula (I):

[0017]

Embedded image HO—Ar ¹ —X—Ar ² —OH ‥‥‥ (I) [In the above formula (I), Ar ¹ and Ar ² each represent a phenylene group which may be substituted. X is

[0018]

Embedded image

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, The divalent organic group is selected from an aryl group having 6 to 12 carbon atoms and an aralkyl group having 6 to 12 carbon atoms, and q represents an integer of 4 to 10. When the diol component (a) and the dicarboxylic acid component (b) are reacted in the presence of a diaryl carbonate (c) to produce a wholly aromatic polyester, the diol component (a) and the diol component 0.55 to 0.95 mol of terephthalic acid and 0.05 to
0.45 mole of isophthalic acid mixed dicarboxylic acid component (b ') and diaryl carbonate (c)
Preliminary polymerization was performed under heating at 0 ° C. or higher, and the reduced viscosity [in phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40), concentration: 1.2 g / 100 ml,
Measured at a temperature of 35 ° C., the same applies hereinafter) 0.1 to 0.4 dl /
g in a pre-polymerization step of preparing a prepolymer in the range of g, and a crystal melting point of 180 ° C. when the prepolymer is crystallized and heated at a rate of 10 ° C./min using a DSC (differential scanning calorimeter). And the heat of crystal fusion is 0.5 to 60 J / g
A crystallization step of preparing a crystallized prepolymer, and the crystallized prepolymer is at or above the glass transition temperature of the wholly aromatic polyester to be produced, and the crystallized prepolymer can maintain a solid state. This method is characterized in that a polymer having a reduced viscosity of 0.6 dl / g or more is obtained by sequentially performing a solid-phase polymerization step of further increasing the degree of polymerization by heating to a temperature in the range.

In the prepolymerization step, the following formula (II)

[0021]

Embedded image

[R ⁵ and R ^{6 in} the above formula (II) are each independently
Hydrogen atom, alkyl group having 1 to 6 carbon atoms, 5 to 10 carbon atoms
Selected from a cycloalkyl group, an aryl group having 6 to 12 carbon atoms and an aralkyl group having 6 to 12 carbon atoms;
There may be a bond between ⁵ and R ⁶ . R ⁷ is a hydrogen atom,
An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and 6 carbon atoms
~ 12 aralkyl groups. n shows the integer of 1-4. A reaction in the presence of a carbonate or bicarbonate of an alkali metal with a pyridine compound represented by the formula:
And in the prepolymerization step, the following formula (III)

[0023]

Embedded image Ti (OR ⁸ ) _n (OR ⁹ ) _m (III) [In the above formula (III), R ⁸ is an alkyl group having 1 to 6 carbon atoms and a cycloalkyl having 5 to 10 carbon atoms. Group or carbon number 6
And R ⁹ is a C 6-12 aralkyl group.
Is an aryl group. n and m are 0 or 1, respectively.
Is an integer of ４4, where n + m = 4. The present invention also encompasses a method for performing the reaction in the presence of the compound represented by the formula:

Further, the diol component (a), the dicarboxylic acid component (b) and the diaryl carbonate (c) are combined with the following formulas (1) and (2)

[0025]

0.95 ≦ B / A ≦ 1.05 ‥‥‥ (1) 1.8 ≦ C / B ≦ 2.2 ‥‥‥ (2) [A in the above formulas (1) and (2) Is the diol component (a), B
Represents the number of moles of the dicarboxylic acid component (b), and C represents the number of moles of the diaryl carbonate (c). ] At the same time is also included in the present invention.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method of the present invention will be described in detail in the order of a raw material monomer, a prepolymerization step, a crystallization step, and a solid phase polymerization step.

[Raw material monomers and the like] The diol component (a) used in the present invention is an aromatic dihydroxy compound represented by the following formula (I).

[0028]

HO-Ar ¹ -X-Ar ² -OH ‥‥‥ (I) [In the above formula (I), Ar ¹ and Ar ² each independently represent a hydrogen atom of a benzene nucleus as a halogen atom or a lower alkyl. A phenylene group which may be substituted with a group or the like. X is

[0029]

Embedded image

An alkylene group or a cycloalkylene group represented by (Where R ¹ , R ² , R ³ and R ⁴
Is independently a hydrogen atom, a halogen atom such as chlorine or bromine, or a carbon atom having 1 to 6 carbon atoms such as a methyl group, an ethyl group, or a propyl group.
And a cycloalkyl group having 5 or 6 carbon atoms such as an alkyl group, a cyclopentyl group and a cyclohexyl group, or an aryl group or an aralkyl group having 6 to 12 carbon atoms such as a phenyl group. q shows the integer of 4-10. ) As such a diol component (a), 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-
Bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2- (4-hydroxyphenyl)
-2- (3,5-dichloro-4-hydroxyphenyl)
Propane and the like are exemplified, and among these, 2,2-bis (4
-Hydroxyphenyl) propane, 1,1-bis (4-
(Hydroxyphenyl) cyclohexane and 2,2-bis (3-methyl-4-hydroxyphenyl) propane are preferred. These diol components may be used in combination of two or more.

As the dicarboxylic acid component (b), a mixed dicarboxylic acid (b) of 0.55 to 0.95 mol of terephthalic acid and 0.05 to 0.45 mol of isophthalic acid per 1 mol of the diol component (a) is used. ') Is used. If the amount of terephthalic acid is less than 0.55 mol, the crystal acceleration becomes extremely slow, which is not preferable. On the other hand, if it is larger than 0.95 mol, the reduced viscosity of the prepolymer obtained in the prepolymerization step is 0.1 d.
Crystallization is not more than 1 / g, which is not preferable. Preferably 60 to 0.90 per mole of the diol component (a).
It is preferred to use moles, more preferably 0.65 to 0.85 moles of terephthalic acid.

The diaryl carbonate (c) includes
For example, diphenyl carbonate, di-p-tolyl carbonate, dinaphthyl carbonate, di-p-chlorophenyl carbonate, phenyl-p-tolyl carbonate and the like can be mentioned, among which diphenyl carbonate is particularly preferred. The diaryl carbonate may be substituted, and may be used alone or in combination of two or more.

[Preliminary Polymerization Step] In the method of the present invention, first, the above-mentioned diol component (a), the above-mentioned mixed dicarboxylic acid component (b '), and diaryl carbonate (c)
Is prepolymerized under heating at 180 ° C. or higher. The temperature of this pre-polymerization needs to be 180 ° C. or higher. That is, if the temperature is lower than 180 ° C., the polymerization rate of the prepolymerization becomes slow, which is not preferable. The polymerization temperature of the prepolymerization is preferably 200 to 350 ° C, more preferably 220 ° C to
320 ° C.

In the prepolymerization step of the present invention, the following formula (I)
I)

[0035]

Embedded image

[In the formula (II), R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
A cycloalkyl group having 10 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms and an aralkyl group having 6 to 12 carbon atoms, and a bond may be present between R ⁵ and R ⁶ . R ⁷ is selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 6 to 12 carbon atoms. n is 1 to 4
Indicates an integer. Or a specific pyridine compound represented by the following formula (III):

[0037]

During embedded image _{^{Ti (OR 8) n (OR}} 9) m ......... (III) [ the formula (III), R ⁸ represents an alkyl group having 1 to 6 carbon atoms, cycloalkyl of 5 to 10 carbon atoms Group or carbon number 6
And R ⁹ is a C 6-12 aralkyl group.
Is an aryl group. n and m are 0 or 1, respectively.
Is an integer of ４4, where n + m = 4. The reaction is preferably performed in the presence of a specific titanium compound represented by the formula:

Examples of the pyridine compound represented by the above formula (II) include 4-aminopyridine, 4-dimethylaminopyridine, 4-diethylaminopyridine, 4-pyrrolidinopyridine, 4-piperidinopyridine, Examples include pyrrolinopyridine and 2-methyl-4-dimethylaminopyridine. Of these, 4-dimethylaminopyridine and 4-pyrrolidinopyridine are particularly preferred.

When the pyridine compound (II) is used as a catalyst in the prepolymerization step, the degree of polymerization may not be easily increased by using the pyridine compound alone. Therefore, the pyridine compound (II) may be used in combination with an alkali metal carbonate or bicarbonate. Is preferred.

The specific titanium compound represented by the above formula (III) includes tetraphenoxy titanium, butoxytriphenoxy titanium, dibutoxy diphenoxy titanium, tetrabutoxy titanium, tetracrezoxy titanium,
Examples thereof include ethoxytricresoxytitanium and diethoxydicrezoxytitanium. Of these, tetraphenoxytitanium and tetrabutoxytitanium are particularly preferred.
This titanium-based compound can be used by itself, and it is not always necessary to coexist another catalyst compound.

In this prepolymerization reaction, first, the diaryl carbonate mainly reacts with the dicarboxylic acid component and the diol component to generate phenols and carbon dioxide gas. Generally, aromatic dicarboxylic acids have a low solubility and a high melting point, so that a high temperature is required to initiate the initial reaction and a long time is required to complete the initial reaction.
For this reason, in the conventional method, the color tone of the obtained polymer deteriorated, and the amount of sublimate generated during the reaction was large.

However, when the compounds represented by the formulas (II) and (III) are used as a catalyst, the initial reaction is started at a very low temperature and in a short time. Therefore, it is presumed that the time required for the reaction is shortened, and the hue of the obtained polymer is significantly improved.

The amount of the pyridine compound (II) and the titanium compound (III) to be used is not particularly limited. In the case of the pyridine compound (II), the amount of the pyridine compound (II) is based on the amount of the mixed dicarboxylic acid component (b ′). Therefore, the amount is preferably 0.01 mol% to 10 mol%. If the amount is less than 0.01 mol%, the effect of the compound as a catalyst becomes insufficient. On the other hand, if it is more than 10 mol%, the physical properties of the obtained polymer may be undesirably reduced. More preferably, 0.
It is from 0.05 mol% to 1 mol%. In addition, such a compound (I
I) may be used in the form of organic or inorganic acid salts. In the present invention, in addition to the pyridine-based compound (II), it is preferable to use an alkali metal carbonate or bicarbonate, specifically, potassium carbonate or potassium bicarbonate, as a transesterification catalyst. By using the alkali metal compound in combination, in the solid phase polymerization step described below, the degree of polymerization can be increased at a higher reaction rate than conventionally known transesterification catalysts, and since the polymerization time is short, a polymer having an extremely excellent hue. Can be obtained.

On the other hand, in the case of the titanium compound (III), 0.0001 with respect to the mixed dicarboxylic acid component (b ′).
~ 2 mol%, preferably 0.0005-0.05 mol%
Is more preferred. Since the titanium compound (III) has excellent catalytic activity, it can be used not only in a small amount compared with a pyridine compound catalyst but also as a transesterification catalyst in the latter stage of the reaction, and a conventionally known transesterification catalyst is used. This has the advantage that the desired wholly aromatic polyester can be produced without the need.

In the method of the present invention, the compound (a)
(B) and (c) are expressed by the following two relational expressions.

[0046]

0.95 ≦ B / A ≦ 1.05 ‥‥‥ (1) 1.8 ≦ C / B ≦ 2.2 ‥‥‥ (2) [In the above formulas, A represents a diol component (a) ), B is a dicarboxylic acid component (b), C is a diaryl carbonate (c)
Is the number of moles. ] Are preferably used in a molar ratio that simultaneously holds.

The above formula (1) is necessary for the ratio of the diol component (a) to the mixed dicarboxylic acid component (b ') in the finally obtained polymer to be substantially 1. When the molar ratio (C / B) of the mixed dicarboxylic acid component (b ′) and the diaryl carbonate (c) in the formula (2) is smaller than 1.8, polymerization is slowed down, and when the molar ratio is larger than 2.2, the obtained polymer Any of these is not preferable since coloring becomes intense. A more preferable range of the molar ratio is 1.85 ≦ C / B ≦
2.15.

The prepolymerization step in the present invention is carried out under normal pressure or reduced pressure. In addition, at normal pressure, it is preferable to use an atmosphere of an inert gas such as nitrogen, argon, or carbon dioxide.

In the present invention, the reduced viscosity of the prepolymer obtained in this prepolymerization step is 0.1 to 0.4 dl / g.
Must be within the range. That is, if the reduced viscosity is lower than 0.1 dl / g, the polymerization time is prolonged when performing solid phase polymerization, which is not preferable. On the other hand, if it exceeds 0.4 dl / g, the prepolymer is difficult to crystallize, which is not preferable.

The reduced viscosity of the prepolymer used in the present invention varies depending on the composition of the polymer and the finally required degree of polymerization, but the preferred reduced viscosity is 0.15 to 0.3 d.
1 / g. In addition, the reduced viscosity referred to in the present invention is a concentration of 1.2 g / 100 ml in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40).
Refers to a value measured at a temperature of 35 ° C.

[Crystallization Step] In the present invention,
The prepolymer of the wholly aromatic polyester obtained in the above-mentioned prepolymerization step is crystallized and has a crystal melting point of 18 when heated at a rate of 10 ° C./min using a DSC (differential scanning calorimeter).
Prepare a crystallized prepolymer that is between 0 ° C and 350 ° C.

As a method of crystallizing the prepolymer, for example, (A) a method of taking out the prepolymer in a molten state and gradually cooling it, (B) a method of taking out the prepolymer in a molten state,
A method in which the quenched prepolymer is heat-treated at 150 to 350 ° C., a method in which the (C) prepolymer is treated with a crystallization solvent and crystallized, and the like are employed. It is also possible to use these crystallization methods in combination.

The crystallization by the heat treatment (B) is performed under normal pressure or reduced pressure. At normal pressure,
It is preferable to use an atmosphere of an inert gas such as nitrogen, argon, or carbon dioxide. On the other hand, examples of the crystallization solvent used in the above (C) include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate, ethers such as tetrahydrofuran and dioxane, benzene, toluene, xylene and the like. Aromatic hydrocarbons, phenols, alcohols such as ethanol,
Amides such as dimethylformamide are exemplified. As the crystallization solvent, acetone, methyl ethyl ketone and phenol are particularly preferable.

In the present invention, the crystallization conditions in this crystallization step are adjusted so that the melting point of the crystallized prepolymer by DSC is 180 ° C. or more and the heat of crystal fusion is 0.5-6.
It is necessary to prepare a crystallized prepolymer that is 0 J / g. The melting point and heat of crystal fusion of the crystallized prepolymer can be controlled by the composition ratio, the degree of polymerization, and the crystallization method.
When the temperature is lower than 0 ° C., the polymerization temperature of solid-state polymerization cannot be increased, resulting in a longer polymerization time. When the heat of crystal fusion is 0.5 J / g or less, fusion of the prepolymer occurs. Both are not preferred. On the other hand, when the heat of crystal fusion is 60 J / g or more, the polymerization rate of solid-state polymerization becomes slow, and as a result, the polymerization time becomes long, which is not preferable. Preferably, the melting point of the crystallized prepolymer is 200 ° C.
The heat of crystal fusion is 1 to 50 J / g, more preferably the melting point of the crystallized prepolymer is 220 ° C. or more, and the heat of crystal fusion is 5 to 30 J / g.

In the present invention, the crystallized prepolymer obtained here is preferably formed into particles having a size suitable for solid-phase polymerization described later, for example, particles having a particle size of 2 mm or less. Therefore, in the present invention, when the particle size of the crystallized prepolymer is larger than this, it is preferable to carry out a pulverization treatment before supplying to the next solid phase polymerization step.

[Solid State Polymerization Step] Next, in the present invention, the above-mentioned crystallized prepolymer is kept at a temperature equal to or higher than the glass transition temperature of the wholly aromatic polyester to be produced, and the crystallized prepolymer is kept in a solid state. The solid phase polymerization is carried out by heating to the temperature range obtained.

The temperature employed in this solid-state polymerization step, which is equal to or higher than the glass transition temperature of the wholly aromatic polyester to be produced and in a range where the crystallized prepolymer can maintain the solid state, depends on the polymer composition and the degree of polymerization. Different, but preferably 180 ° C to 350 ° C, more preferably 200 ° C to 29 ° C.
0 ° C. Since the glass transition temperature and the upper limit temperature at which the solid state can be maintained increase with the progress of polymerization, the heating temperature may be increased stepwise or gradually.

The solid-state polymerization step of the present invention is also carried out under normal pressure or reduced pressure. At normal pressure, it is preferable to be in an atmosphere of an inert gas such as nitrogen, argon, or carbon dioxide.

This solid-phase polymerization must be carried out until the wholly aromatic polyester has a reduced viscosity of 0.6 dl / g or more. If the reduced viscosity is lower than 0.6 dl / g, the heat resistance and toughness of the obtained polymer are insufficient, which is not preferable. In practice, the upper limit of the reduced viscosity is preferably about 2.0.

In the present invention, various additives such as a stabilizer, a colorant, a pigment and a lubricant may be added to the wholly aromatic polyester during or after its production, if necessary.

[0061]

According to the production method of the present invention, a wholly aromatic polyester having a good color tone and a high degree of polymerization is preliminarily esterified with a dicarboxylic acid component or a diol component while maintaining good heat resistance and mechanical properties. Without the need, it can be obtained immediately from a dicarboxylic acid and a diol by an inexpensive process. The wholly aromatic polyester according to the method of the present invention has heat resistance, transparency and the like, and can be suitably used for molded articles such as light covers for automobiles and electronic members.

[0062]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight” unless otherwise specified.

The reduced viscosity was measured in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40) at a temperature of 35 ° C., as described above.
The thermal properties of the polymer are measured by DSC (DSC2920: TA Ins
truments) at a heating rate of 10 ° C./min.

Example 1 46.5 parts of terephthalic acid, 19.9 parts of isophthalic acid, 91.2 parts of 2,2-bis (4-hydroxyphenyl) propane, 171.2 parts of diphenyl carbonate, 4-dimethylamino Pyridine 0.04
9 parts and 0.016 part of potassium carbonate were placed in a reaction vessel having a vacuum distillation system equipped with a stirrer and a nitrogen inlet.
The reaction was started at 00 ° C. After 30 minutes, the temperature was raised to 220 ° C., and after confirming the distillation of phenol at the same temperature, the pressure in the system was gradually reduced. Four hours after the start of the reaction, it was confirmed that the raw materials were uniformly dissolved. After that, the temperature was further increased and the pressure was reduced.
mmHg (133.4 Pa). 20 under the same conditions
The polymerization was carried out for a few minutes to give a transparent prepolymer which was only slightly yellow. The reduced viscosity of this prepolymer is 0.1.
It was 24 dl / g.

The above prepolymer was melted at 230 ° C.
The mixture was gradually cooled to that temperature and maintained at the same temperature for 2 hours to obtain a white and opaque crystallized prepolymer. The reduced viscosity of the obtained crystallized prepolymer is 0.27 dl / g, and the heat of crystal fusion is 1
The crystal melting point was 2.5 J / g and the crystal melting point was 295 ° C. After pulverizing the crystallized prepolymer to a particle size of 0.5 to 1.2 mm,
0.5 mmHg in a reaction vessel having a vacuum distillation system
(66.7 Pa) under 220 ° C. for 3 hours and 230 ° C. for 3 hours.
Heat at 240 ° C. for 3 hours and 250 ° C. for 3 hours.
The reduced viscosity of the obtained amorphous wholly aromatic polyester (hereinafter, referred to as polyarylate) was 0.81 dl / g, and the glass transition temperature was 190 ° C.

Example 2 Instead of 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid, 39.8 terephthalic acid was used.
Example 1 except that 26.6 parts of isophthalic acid were used.
The reaction was carried out under the same conditions as described above. The resulting prepolymer is
Transparent, slightly yellow colored, reduced viscosity 0.2
It was 7 dl / g.

By immersing the above prepolymer in acetone for 8 hours, a white and opaque crystallized prepolymer was obtained. The reduced viscosity of the obtained crystallized prepolymer is 0.27 dl /
g, heat of crystal fusion: 5.1 J / g, crystal melting point: 205 ° C
Met. 0.5 to 1.2 mm of the crystallized prepolymer
After pulverizing to a particle size of 5 μm, the mixture was placed in a reaction vessel having a vacuum distillation system, and heated at 190 ° C. under 0.5 mmHg (66.7 Pa).
Time, 5 hours at 200 ° C, 3 hours at 220 ° C, 230 ° C
For 3 hours, 240 ° C. for 3 hours, and 250 ° C. for 3 hours. The reduced viscosity of the obtained polyarylate is 0.68 dl.
/ G, glass transition temperature was 188 ° C.

Example 3 Instead of 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid, 53.1 parts of terephthalic acid were used.
The reaction was carried out under the same conditions as in Example 1, except that 13.3 parts of isophthalic acid and 13.3 parts of isophthalic acid were used. The resulting prepolymer is
Transparent, slightly yellow colored, reduced viscosity 0.2
It was 7 dl / g.

The temperature of the above prepolymer was increased from room temperature to 230 ° C., and maintained at the same temperature for 2 hours to obtain a white and opaque crystallized prepolymer. The reduced viscosity of the obtained crystallized prepolymer is 0.29 dl / g, and the heat of crystal fusion is 7.8.
J / g, crystal melting point: 339 ° C. After pulverizing the crystallized prepolymer to a particle size of 0.5 to 1.2 mm, the prepolymer is charged into a reaction vessel having a vacuum distillation system, and the prepolymer having a diameter of 0.5 mmHg (66.
7 Pa) at 220 ° C. for 3 hours, 230 ° C. for 3 hours, 2
Heat at 40 ° C. for 3 hours and 250 ° C. for 3 hours. The reduced viscosity of the obtained polyarylate was 0.80 dl / g, and the glass transition temperature was 198 ° C.

Example 4 46.5 parts of terephthalic acid, 19.9 parts of isophthalic acid, 91.2 parts of 2,2-bis (4-hydroxyphenyl) propane, 171.2 parts of diphenyl carbonate, 4dimethylaminopyridine 0.049
And 0.052 parts of di-n-butyltin diacetate were placed in a reaction vessel having a vacuum distillation system equipped with a stirrer and a nitrogen inlet, and the reaction was started at 200 ° C. 30 minutes later, 2
The temperature was raised to 20 ° C., and after confirming the distillation of phenol at the same temperature, the pressure in the system was gradually reduced. 4 hours after the start of the reaction,
It was confirmed that the raw materials were uniformly dissolved. Thereafter, the temperature was further increased and the pressure was reduced.
0 ° C. and about 10 mmHg (133.4 Pa). Polymerization was carried out under the same conditions for 40 minutes to obtain a transparent prepolymer that was slightly yellow colored. The reduced viscosity of this prepolymer was 0.22 dl / g.

The above prepolymer was melted at 230 ° C.
After cooling to room temperature and maintaining the same temperature for 4 hours, a white and opaque crystallized prepolymer was obtained. The reduced viscosity of the obtained crystallized prepolymer was 0.24 dl / g, the heat of crystal fusion was 9.5 J / g, and the crystal melting point was 288 ° C. After pulverizing the crystallized prepolymer to a particle size of 0.5 to 1.2 mm,
0.5 mmHg in a reaction vessel having a vacuum distillation system
(66.7 Pa) under 220 ° C for 6 hours and 230 ° C for 6 hours.
Heat at 240 ° C. for 6 hours and 250 ° C. for 10 hours. The reduced viscosity of the obtained polyarylate is 0.69 dl.
/ G, glass transition temperature was 189 ° C.

Example 5 Instead of 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid, 53.1 parts of terephthalic acid were used.
And the reaction was carried out under the same conditions as in Example 4 except that 13.3 parts of isophthalic acid was used. The resulting prepolymer is
Transparent, slightly yellow colored, reduced viscosity 0.2
It was 5 dl / g.

The temperature of the above prepolymer was raised from room temperature to 230 ° C. and maintained at the same temperature for 4 hours to obtain a white and opaque crystallized prepolymer. The reduced viscosity of the obtained crystallized prepolymer is 0.27 dl / g, and the heat of crystal fusion is 10.
The crystal melting point was 325 ° C., 8 J / g. After pulverizing the crystallized prepolymer to a particle size of 0.5 to 1.2 mm, the prepolymer is placed in a reaction vessel having a vacuum distillation system, and the prepolymer having a diameter of 0.5 mmHg (6
Under 6.7 Pa), heating was performed at 220 ° C. for 6 hours, 230 ° C. for 6 hours, 240 ° C. for 6 hours, and 250 ° C. for 10 hours.
The reduced viscosity of the obtained polyarylate is 0.71 dl /
g, glass transition temperature was 190 ° C.

Example 6 46.5 parts of terephthalic acid, 19.9 parts of isophthalic acid, 91.2 parts of 2,2-bis (4-hydroxyphenyl) propane, 171.2 parts of diphenyl carbonate and 0 parts of tetraphenoxytitanium .01
7 parts were placed in a reaction vessel having a vacuum distillation system equipped with a stirrer and a nitrogen inlet, and the reaction was started at 200 ° C.
After 30 minutes, the temperature was raised to 220 ° C., and after confirming the distillation of phenol at the same temperature, the pressure in the system was gradually reduced. Two hours after the start of the reaction, it was confirmed that the raw materials were uniformly dissolved. Thereafter, the temperature was further increased and the pressure was reduced. After 3 hours from the start of the reaction, the inside of the system was heated at 300 ° C. and about 10 mmHg (133.4 P
a). Polymerization was conducted for 5 minutes under the same conditions to obtain a pale red transparent prepolymer. The reduced viscosity of this prepolymer was 0.24 dl / g.

The above prepolymer was melted at 230 ° C.
The mixture was gradually cooled to that temperature and maintained at the same temperature for 2 hours to obtain a white and opaque crystallized prepolymer. The reduced viscosity of the obtained crystallized prepolymer is 0.27 dl / g, and the heat of crystal fusion is 1
The crystal melting point was 1.5 J / g and the crystal melting point was 285 ° C. After pulverizing the crystallized prepolymer to a particle size of 0.5 to 1.2 mm,
0.5 mmHg in a reaction vessel having a vacuum distillation system
(66.7 Pa) under 220 ° C. for 3 hours and 230 ° C. for 3 hours.
Heat at 240 ° C. for 2 hours and 250 ° C. for 2 hours.
The reduced viscosity of the obtained polyarylate is 0.79 dl /
g, glass transition temperature was 190 ° C.

Comparative Example 1 Instead of 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid, 33.2 parts of terephthalic acid and 33.2 parts of isophthalic acid were used as dicarboxylic acid components.
The reaction was carried out under the same conditions as in Example 1 except for using parts.
The obtained prepolymer was transparent with a slight yellow coloring, and had a reduced viscosity of 0.24 dl / g.

The above prepolymer was melted at 230 ° C.
The resultant prepolymer was pale yellow and transparent, had a reduced viscosity of 0.26 dl / g, and the crystalline melting point could not be observed by DSC. After pulverizing the prepolymer to a particle diameter of 0.5 to 1.2 mm, the prepolymer is put into a reaction vessel having a vacuum distillation system,
Solid-state polymerization was started at 220 ° C. under mHg (66.7 Pa), but was fused in several minutes, and no improvement in reduced viscosity was observed.

Comparative Example 2 Terephthalic acid was replaced with 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid.
The reaction was carried out under the same conditions as in Example 1 except that 2 parts and 33.2 parts of isophthalic acid were used. The obtained prepolymer was transparent with a slight yellow coloring, and had a reduced viscosity of 0.24 dl / g.

By immersing the above prepolymer in acetone for 12 hours, a white and opaque crystallized prepolymer was obtained.
The reduced viscosity of the obtained crystallized prepolymer is 0.22 dl.
/ G, crystal heat of fusion 0.3 J / g, crystal melting point 205
° C. 0.5 to 1.2 m of the crystallized prepolymer
After being pulverized to a particle diameter of 5 m, the mixture was placed in a reaction vessel having a vacuum distillation system, and heated at 190 ° C under 0.5 mmHg (66.7 Pa).
Heating was performed at 200 ° C. for 5 hours, but fusion occurred during the temperature increase at 210 ° C., and the reduced viscosity increased only to 0.29 dl / g.

Comparative Example 3 Terephthalic acid was replaced with 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid.
The reaction was carried out under the same conditions as in Example 4 except that 2 parts and 33.2 parts of isophthalic acid were used. The obtained prepolymer was transparent, slightly yellow colored, and had a reduced viscosity of 0.29 dl / g.

The above prepolymer was melted at 230 ° C.
The resulting prepolymer was pale yellow and transparent, had a reduced viscosity of 0.30 dl / g, and the crystal melting point could not be observed by DSC. After pulverizing the prepolymer to a particle diameter of 0.5 to 1.2 mm, the prepolymer is put into a reaction vessel having a vacuum distillation system,
Solid-state polymerization was started at 220 ° C. under mHg (66.7 Pa), but was fused in several minutes, and no improvement in reduced viscosity was observed.

Comparative Example 4 Terephthalic acid was replaced with 46.5 parts of terephthalic acid and 19.9 parts of isophthalic acid.
The reaction was carried out under the same conditions as in Example 4 except that 2 parts and 33.2 parts of isophthalic acid were used. The obtained prepolymer was transparent, slightly yellow colored, and had a reduced viscosity of 0.29 dl / g.

The above prepolymer was immersed in acetone for 12 hours. The obtained prepolymer was pale yellow and transparent, had a reduced viscosity of 0.29 dl / g, and the melting point of the crystal could not be observed by DSC. 0.5% of the prepolymer
After pulverizing to a particle diameter of ~ 1.2 mm, the mixture was placed in a reaction vessel having a vacuum distillation system, and was subjected to 2 mm under 0.5 mmHg (66.7 Pa).
Solid-state polymerization was started at 20 ° C., but fusion occurred within a few minutes, and no improvement in reduced viscosity was observed.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuaki Kido 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Pref. Teijin Co., Ltd. (72) Inventor Shunichi Matsumura 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Pref. F-term in Iwakuni Research Center (reference) 4J029 AA04 AB04 AC01 AD01 AD07 AD08 AE01 BB08A CB05A CB06A HC05B JC233 JF011 JF041 JF321 KD02 KD09 KE02 KE12

Claims (6)

[Claims] 1. A compound represented by the following formula (I): HO-Ar ¹ -X-Ar ² -OH 上 記 (I) wherein Ar ¹ and Ar ² in the above formula (I) are each substituted Is a good phenylene group. X is (Where R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, Selected from 12 aryl groups and aralkyl groups having 6 to 12 carbon atoms, and q represents an integer of 4 to 10.)
Is a valence organic group. When the aromatic diol component (a) and the aromatic dicarboxylic acid component (b) are reacted in the presence of a diaryl carbonate (c) to produce a wholly aromatic polyester, the diol component (a) And 0.55 to 0.95 mol of terephthalic acid and 0.05 mol per mol of the diol component.
A mixed dicarboxylic acid component (b ′) with .about.0.45 mol of isophthalic acid and a diaryl carbonate (c)
Preliminary polymerization under heating at 80 ° C. or higher, reduced viscosity (in phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40), concentration 1.2 g / 100 ml,
A prepolymerization step of preparing a prepolymer having a temperature (measured at 35 ° C.) in the range of 0.1 to 0.4 dl / g; crystallizing the prepolymer and using a DSC (differential scanning calorimeter) The crystal melting point when the temperature is raised at 10 ° C./min is 180 ° C. or more and the heat of crystal fusion is 0.5 to 60 J / g.
A crystallization step of preparing a crystallized prepolymer, and the crystallized prepolymer is at or above the glass transition temperature of the wholly aromatic polyester to be produced, and the crystallized prepolymer can maintain a solid state. A polymer having a reduced viscosity of 0.6 dl / g or more (measured under the same conditions as above) is obtained by sequentially performing a solid-state polymerization step of further increasing the degree of polymerization by heating to a temperature in the range. A method for producing a wholly aromatic polyester. 2. In the pre-polymerization step, the following formula (II): [R ⁵ and R ^{6 in} the above formula (II) each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, Number 6 ~
It is selected from 12 aralkyl groups, and there may be a bond between R ⁵ and R ⁶ . R ⁷ is a hydrogen atom, having 1 to 6 carbon atoms
, An alkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 6 to 12 carbon atoms. n shows the integer of 1-4. The method for producing a wholly aromatic polyester according to claim 1, wherein the reaction is carried out in the presence of a pyridine compound represented by the following formula: 3. In the prepolymerization step, the compound of the formula (II)
3. The method for producing a wholly aromatic polyester according to claim 2, wherein the reaction is carried out in the coexistence of a pyridine compound of formula (1) with an alkali metal carbonate or bicarbonate. 4. The method according to claim 3, wherein the alkali metal is potassium.
A method for producing the wholly aromatic polyester described in the above. 5. In the prepolymerization step, the following formula (II)
I) embedded image Ti (OR ⁸ ) _n (OR ⁹ ) _m (III) [In the above formula (III), R ⁸ is an alkyl group having 1 to 6 carbon atoms, Cycloalkyl group or carbon number 6
And R ⁹ is a C 6-12 aralkyl group.
Is an aryl group. n and m are 0 or 1, respectively.
Is an integer of ４4, where n + m = 4. The method for producing a wholly aromatic polyester according to claim 1, wherein the reaction is carried out in the presence of a titanium compound represented by the following formula: 6. An aromatic diol component (a), an aromatic dicarboxylic acid component (b) and a diaryl carbonate (c) are represented by the following formulas (1) and (2): 0.95 ≦ B / A ≦ 1.05 ‥‥‥ (1) 1.8 ≦ C / B ≦ 2.2 ‥‥‥ (2) [In the above formulas (1) and (2), A is an aromatic diol component (a), and B is The aromatic dicarboxylic acid component (b) and C are the number of moles of the diaryl carbonate (c). The method for producing a wholly aromatic polyester according to any one of claims 1 to 5, wherein the molar ratio satisfies the above conditions.