JP2008138221A - Liquid crystalline polyester and method for producing the same - Google Patents

Abstract

(IV)
【選択図】なしDisclosed is a liquid crystalline polyester that does not generate acetic acid gas when formed into a molded product, and a method for producing the same.
When melt polymerizing an aromatic hydroxycarboxylic acid represented by the following formula (I), an aromatic diol represented by the following formula (II), and an aromatic dicarboxylic acid represented by the following formula (III): And a diaryl carbonate represented by the following formula (IV) as an esterification reagent.
HO-R ₁ -COOH (I)
HO-R ₂ -OH (II)
HOOC-R ₃ -COOH (III)

(IV)
[Selection figure] None

Description

  The present invention relates to a liquid crystalline polyester and a method for producing the same.

Liquid crystalline polyesters having an aromatic ring skeleton are widely used in the electrical and electronic fields as materials having excellent heat resistance and moldability.
The liquid crystalline polyester includes, for example, an aromatic hydroxycarboxylic acid such as parahydroxybenzoic acid, an aromatic diol such as 4,4′-hydroxybiphenyl, and an aromatic dicarboxylic acid such as terephthalic acid as an esterification agent. It is manufactured by melt polymerization using a fatty acid anhydride such as acetic anhydride.
However, since acetic anhydride is used as the esterification agent in the above method, acetic anhydride remaining in the molded product obtained by compounding, heating and molding the liquid crystalline polyester is decomposed, and further polymerization proceeds. As a result, acetic acid is produced as a by-product, and acetic acid gas is generated to corrode metal wiring.

  An object of the present invention is to provide a liquid crystalline polyester that does not generate acetic acid gas when it is formed into a molded product, and a method for producing the same.

As a result of intensive studies to find a method for producing a liquid crystalline polyester having no problems as described above, the present inventors have melt polymerized an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid. When diaryl carbonates were used as esterification reagents, it was found that acetic acid gas was not generated when the resulting liquid crystalline polyester was used as a molded product, and the present invention was completed.

(IV)
（式中、Ｒ₁、Ｒ₃は置換されていてもよいアリーレン基を表わし、Ｒ₂は、置換されていてもよいアリーレン基または下記式(V)

(V)
で示される基を表わし、R₄〜R₇は、それぞれ独立に、水素原子またはハロゲン原子を表わすか、炭素数１〜６のアシルオキシ基、または炭素数１〜６のアルキル基を表わし、Xは、−Ｏ−、−Ｓ−、―ＳＯ₂−、−ＣＯ−、−Ｃ₆Ｈ₁₀−またはアルキレン基を表わす。） That is, the present invention, an aromatic hydroxycarboxylic acid represented by the following formula (I), an aromatic diol represented by the following formula (II), an aromatic dicarboxylic acid represented by the following formula (III), below The present invention provides a method for producing a liquid crystalline polyester characterized by using a diaryl carbonate represented by the following formula (IV) as an esterification reagent when melt polymerization is performed in the presence of (a) .

HO-R ₁ -COOH (I)
HO-R ₂ -OH (II)
HOOC-R ₃ -COOH (III)

(IV)
Wherein R ₁ and R ₃ represent an optionally substituted arylene group, and R ₂ represents an optionally substituted arylene group or the following formula (V)

(V)
R _{4 to} R ₇ each independently represents a hydrogen atom or a halogen atom, an acyloxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, and X represents , -O -, - S -, - SO 2 -, - CO -, - represents an or an alkylene group - C ₆ H _10. )

  ADVANTAGE OF THE INVENTION According to this invention, when it is set as a molded article, it becomes possible to provide the liquid crystalline polyester which does not generate | occur | produce acetic acid gas, and its manufacturing method.

  The liquid crystalline polyester of the present invention comprises an aromatic hydroxycarboxylic acid represented by the above formula (I), an aromatic diol represented by the above formula (II), and an aromatic dicarboxylic acid represented by the above formula (III), It can be obtained by melt polymerization using a diaryl carbonate represented by the above formula (IV) as an esterification reagent.

In the formula (I), R ₁ represents an optionally substituted arylene group.
Examples of the arylene group include a phenylene group, a naphthalene group, and a diphenylene group. These groups may be substituted with a halogen atom or an alkyl group having 1 to 6 carbon atoms.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a t-butyl group.

Examples of the aromatic hydroxycarboxylic acid (I) include parahydroxybenzoic acid, metahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-3-naphthoic acid, 1-hydroxy-4-naphthoic acid, 2,6-dichloro-parahydroxybenzoic acid, 2-chloro-parahydroxybenzoic acid, 2,6-difluoro-parahydroxybenzoic acid, 4-hydroxy-4′-biphenylcarboxylic acid, and the like can be mentioned. Two or more kinds may be used in combination.
Among these, parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid are preferably used because they are easily available.

(V)
で示される基を表わす。
アリーレン基としては、フェニレン基、ナフタレン基、ジフェニレン基などが挙げられ、これらの基は、ハロゲン原子、炭素数１〜６のアルキル基、炭素数１〜６のアシルオキシ基、フェニル基またはニトロ基で置換されていてもよい。
ハロゲン原子、炭素数１〜６のアルキル基としては、前記と同じものが挙げられる。
炭素数１〜６のアシルオキシ基としては、例えば、ホルミルオキシ基、アセチルオキシ基（アセトキシ基）、プロピルオキシ基などが挙げられる。
また、式(V)中、Xは、−Ｏ−、−Ｓ−、―ＳＯ₂−、−ＣＯ−、−Ｃ₆Ｈ₁₀−またはアルキレン基を表わし、R₆、R₇は、それぞれ独立に、水素原子またはハロゲン原子を表わすか、炭素数１〜６のアシルオキシ基、または炭素数１〜６のアルキル基を表わす。
ハロゲン原子、炭素数１〜６のアシルオキシ基、炭素数１〜６のアルキル基としては、前記と同じものが挙げられる。 In the formula (II), R ₂ represents an optionally substituted arylene group or the following formula (V)

(V)
Represents a group represented by
Examples of the arylene group include a phenylene group, a naphthalene group, and a diphenylene group. These groups are a halogen atom, an alkyl group having 1 to 6 carbon atoms, an acyloxy group having 1 to 6 carbon atoms, a phenyl group, or a nitro group. May be substituted.
Examples of the halogen atom and the alkyl group having 1 to 6 carbon atoms are the same as those described above.
Examples of the acyloxy group having 1 to 6 carbon atoms include formyloxy group, acetyloxy group (acetoxy group), propyloxy group and the like.
In the formula (V), X represents —O—, —S—, —SO ₂ —, —CO—, —C ₆ H ₁₀ — or an alkylene group, and R ₆ and R ₇ are each independently Represents a hydrogen atom or a halogen atom, an acyloxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
Examples of the halogen atom, the acyloxy group having 1 to 6 carbon atoms, and the alkyl group having 1 to 6 carbon atoms are the same as described above.

Examples of R ₂ include the following groups.

Examples of the aromatic diol (II) include 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, methylhydroquinone, chlorohydroquinone, acetoxyhydroquinone, nitrohydroquinone, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1 , 6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) Propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) ) Propane, bis- (4-hydro) Shifeniru) methane, bis - (4-hydroxy-3,
5-dimethylphenyl) methane, bis- (4-hydroxy-3,5-dichlorophenyl) methane, bis- (4-hydroxy-3,5-dibromophenyl) methane, bis- (4-hydroxy-3-methylphenyl) Methane, bis- (4-hydroxy-3-chlorophenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis- (4-hydroxyphenyl) ketone, bis- (4-hydroxy-3,5-dimethyl) Phenyl) ketone, bis- (4-hydroxy-3,5-dichlorophenyl) ketone, bis- (4-hydroxyphenyl) sulfide, bis- (4-hydroxyphenyl) sulfone, bis- (4-hydroxyphenyl) ether, etc. These may be used alone or in combination of two or more.
Among these, 4,4′-dihydroxybiphenyl, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, and bis- (4-hydroxyphenyl) sulfone are easily available. Therefore, it is preferably used.

In formula (III), R ₃ represents an optionally substituted arylene group.
Examples of the arylene group include a phenylene group, a naphthalene group, and a diphenylene group. These groups may be substituted with a halogen atom or an alkyl group having 1 to 6 carbon atoms.
Examples of the halogen atom and the alkyl group having 1 to 6 carbon atoms are the same as those described above.

Examples of the aromatic dicarboxylic acid (III) include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, methyl terephthalic acid, and methyl isophthalic acid. These may be used alone or in combination of two or more.
Among these, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferably used because they are easily available.

In formula (IV), R ₄ and R ₅ each independently represents a hydrogen atom or a halogen atom, an acyloxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
Examples of the halogen atom, the alkyl group having 1 to 6 carbon atoms, and the acyloxy group having 1 to 6 carbon atoms are the same as those described above.

  Examples of the diaryl carbonates (IV) include diphenyl carbonate, di-p-tolyl carbonate, di-p-chlorophenyl carbonate, and phenyl-p-tolyl carbonate. Among these, diphenyl carbonate is preferably used. The These diallyl carbonate compounds may be used alone or in combination of two or more.

The usage-amount of aromatic hydroxycarboxylic acid (I) is 30-80 mol% with respect to the total amount of aromatic hydroxycarboxylic acid (I), aromatic diol (II), and aromatic dicarboxylic acid (III). It is preferably 40 to 70 mol%, more preferably 50 to 65 mol%.
The amount of aromatic diol (II) used is 35 to 10 mol% with respect to the total amount of aromatic hydroxycarboxylic acid (I), aromatic diol (II) and aromatic dicarboxylic acid (III). Preferably, it is 30 to 15 mol%, more preferably 25 to 17.5 mol%.
The amount of aromatic dicarboxylic acid (III) used is 35 to 10 mol% with respect to the total amount of aromatic hydroxycarboxylic acid (I), aromatic diol (II) and aromatic dicarboxylic acid (III). Is preferable, it is more preferable that it is 30-15 mol%, and it is further more preferable that it is 25-17.5 mol%.
The molar ratio ((II) / (III)) between the aromatic diol (II) and the aromatic dicarboxylic acid (III) is 90/100 to 100/90 . If it is less than 90/100 or greater than 100/90, the heat resistance and fluidity tend to be poor.

  The amount of diaryl carbonates (IV) used is 0.9 to 1.1 times equivalent to the total amount of aromatic hydroxycarboxylic acid (I), aromatic diol (II) and aromatic dicarboxylic acid (III). It is preferable that If it is less than 0.9 times equivalent, unreacted aromatic diol or aromatic dicarboxylic acid tends to sublimate at the time of polymerization, and the reaction system tends to block, and if it exceeds 1.1 times equivalent, There is a tendency for coloring to become remarkable.

  The above (I) to (IV) are preferably charged into the reaction vessel at the same time from the beginning of the reaction, but the diaryl carbonates (IV) may be added to the reaction vessel in several times from the start of the reaction.

When adding diaryl carbonates (IV) to aromatic hydroxycarboxylic acid (I), aromatic diol (II), aromatic dicarboxylic acid (III) and performing melt polymerization,
(A) Imidazole compound represented by the following formula (VI)
In the presence of
The imidazole compound represented by the following formula (VI) is preferably charged into the reaction vessel simultaneously with the above (I) to (IV) from the beginning of the reaction, but the diaryl carbonates (IV) are divided into several times from the start of the reaction. It may be added to the reaction vessel.

(VI)
で示されるイミダゾール化合物において、R₈〜R₁₁は、それぞれ独立に、水素原子を表わすか、炭素数１〜４のアルキル基、ヒドロキシメチル基、シアノ基、炭素数２〜５のシアノアルキル基、炭素数２〜５のシアノアルコキシ基、カルボキシル基、アミノ基、炭素数１〜４のアミノアルキル基、炭素数１〜４のアミノアルコキシ基、フェニル基、ベンジル基、フェニルプロピル基またはフォルミル基を表わす。
炭素数１〜４のアルキル基としては、例えば、メチル基、エチル基、プロピル基などが挙げられる。
炭素数２〜５のシアノアルキル基としては、例えば、シアノメチル基、シアノエチル基、シアノプロピル基などが挙げられる。
炭素数２〜５のシアノアルコキシ基としては、例えば、シアノメトキシ基、シアノエトキシ基、シアノブトキシ基などが挙げられる。
炭素数１〜４のアミノアルキル基としては、例えば、アミノメチル基、アミノエチル基、アミノプロピル基などが挙げられる。
炭素数１〜４のアミノアルコキシ基としては、例えば、アミノメトキシ基、アミノエトキシ基、アミノブトキシ基などが挙げられる。

(VI)
In in imidazole compound represented, R ₈ to R ₁₁ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a cyano group, a cyanoalkyl group having 2 to 5 carbon atoms, C2-C5 cyanoalkoxy group, carboxyl group, amino group, C1-C4 aminoalkyl group, C1-C4 aminoalkoxy group, phenyl group, benzyl group, phenylpropyl group or formyl group .
Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, and a propyl group.
Examples of the cyanoalkyl group having 2 to 5 carbon atoms include a cyanomethyl group, a cyanoethyl group, a cyanopropyl group, and the like.
Examples of the cyanoalkoxy group having 2 to 5 carbon atoms include a cyanomethoxy group, a cyanoethoxy group, a cyanobutoxy group, and the like.
Examples of the aminoalkyl group having 1 to 4 carbon atoms include an aminomethyl group, an aminoethyl group, and an aminopropyl group.
Examples of the aminoalkoxy group having 1 to 4 carbon atoms include an aminomethoxy group, an aminoethoxy group, and an aminobutoxy group.

Specific examples of the imidazole compound (VI) include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1,2-dimethylimidazole, 1,4-dimethylimidazole, 2,4-dimethylimidazole, 1-methyl-2-ethylimidazole, 1-methyl-4ethylimidazole, 1-ethyl-2-methylimidazole, 1-ethyl-2-ethylimidazole, 1 -Ethyl-2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1 -Cyanoethyl-2 Phenylimidazole, 4-cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole, 2-alkyl-4-formylimidazole, 2,4-dialkyl-5-formylimidazole, 1- Benzyl-2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1-aminoethyl-2-ethylimidazole, 4-formylimidazole, 2-methyl-4-formylimidazole, 4-methyl-5- Examples include formylimidazole, 2-ethyl-4-methyl-5-formylimidazole, 2-phenyl-4-methyl-4-formylimidazole, and the like. Methylimidazole and 2-methylimidazole are preferred.

The imidazole compound represented by the formula (VI) exhibits excellent catalytic activity even when used alone in melt polymerization, but may be used in combination of two or more as required. The amount of the imidazole compound (VI) used (when two or more are used in combination) is the total weight of the aromatic hydroxycarboxylic acid (I), aromatic diol (II), and aromatic dicarboxylic acid (III). In contrast, it is preferably 10 to 5000 ppm.

The temperature of the melt polymerization is 180 to 320 ° C. at the initial stage of polymerization, and this is 0.3 to 5.0 ° C./min. It is preferable to raise the temperature at a rate of 280 to 400 ° C. finally. Phenol is produced as a by-product of the polymerization, and it is preferable to perform polymerization while removing phenol out of the system.
The atmosphere for melt polymerization is preferably an atmosphere of an inert gas such as nitrogen or argon under normal pressure. The melt polymerization can also be carried out under reduced pressure.
The reaction time for melt polymerization is not particularly limited, but is usually about 0.3 to 10 hours.

The liquid crystalline polyester produced by melt polymerization is solidified and then pulverized to obtain the obtained liquid crystalline polyester powder , and then the liquid crystalline polyester powder is subjected to solid phase polymerization . Solid phase polymerization can be carried out in any atmosphere under normal pressure or reduced pressure. Moreover, as an apparatus used for solid layer polymerization, a batch apparatus, a continuous apparatus, etc. are mentioned, for example.
As a method of solid layer polymerization, for example, the liquid crystalline polyester powder is stirred under heating in a high boiling point solvent such as a mixture of diphenyl and diphenyl ether or diphenyl sulfone, and then the high boiling point solvent is removed, or the liquid crystal Examples thereof include a method in which the shape is changed, such as by pelletizing the conductive polyester powder with a granulator, and then heat-treated in an inert gas atmosphere or under reduced pressure.
The heating temperature and the heat treatment temperature are usually about 200 to 350 ° C., and the treatment time is usually about 1 to 20 hours. Examples of the heat treatment apparatus include known dryers, reactors, inert ovens, mixers, and electric furnaces.

The weight average molecular weight of the liquid crystalline polyester thus obtained is not particularly limited, but is preferably 10,000 to 50,000.
It can be confirmed by observation with a deflection microscope that the obtained polyester is liquid crystalline.
The liquid crystalline polyester of the present invention can be formed into a molded product by, for example, a melt molding method such as injection molding.

  The liquid crystalline polyester of the present invention contains a structural unit derived from aromatic hydroxycarboxylic acid (I), a structural unit derived from aromatic diol (II), and a structural unit derived from aromatic dicarboxylic acid (III), It is characterized by being substantially free of fatty acids or fatty acid anhydrides.

Examples of the fatty acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, pivalic acid, 2-ethylhexanoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, dibromoacetic acid, tribromoacetic acid, mono Examples include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, glutaric acid, maleic acid, succinic acid, and β-bromopropionic acid.
Examples of fatty acid anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, anhydrous Examples thereof include monobromoacetic acid, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, and β-bromopropionic anhydride.

  The liquid crystalline polyester of the present invention is excellent in heat resistance, moldability, mechanical strength (tensile strength, impact strength, etc.), and does not generate acetic acid gas when molded, so it has high heat resistance for electronic and electrical parts. It can be suitably used for material applications.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, it cannot be overemphasized that this invention is not what is limited by an Example.

The deflection temperature under load (heat resistance index), the thin wall flow length (moldability index), and the amount of gas generated were measured by the following methods.
(1) Deflection temperature under load A test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 6.4 mm was used.
Based on D648, measurement was performed with a load of 18.6 kg / cm ² .
The heat resistance was evaluated by measuring the temperature at a constant strain under a constant load.
(2) Thin wall flow length Using a PS40E5ASE type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., a thin wall flow length measuring mold shown in FIG. 1 was used as a mold. The cylinder temperature of the molding machine was set to 350 ° C. and the mold temperature was set to 130 ° C.
Pellets produced by a twin screw extruder (Ikegai Iron Works Co., Ltd. PCM-30) were supplied to the molding machine to obtain a molten resin. The molten resin injected from the nozzle at the tip of the cylinder of the molding machine passes through the sprue (1) of the mold, passes through the runner (2) and the gate (3), and fills the inside of the four cavities (4) in FIG. Is done. Thereafter, the molten resin is cooled and solidified to obtain a molded product. The molded product was taken out, and the lengths (in the flow direction) of the resin filled in the four cavities were measured. The average value was calculated and used as the thin-wall flow length (mm). The larger the thin wall flow length, the better the thin formability.
The resin moldability was evaluated by comparing the flow length when the resin was molded under the same conditions.
(3) Amount of generated acetic acid gas
JIS K71131 (1/2) dumbbell x 0.8mmt is weighed in a glass bottle, 5g, sealed, heat-treated at 120 ° C for 20 hours, and the total amount of acetic acid gas generated is headspace gas chromatograph (GC15A / HSS3A manufactured by Shimadzu Corporation) Measured with

Example 1
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, p-hydroxybenzoic acid 663 g (4.8 mol), 4,4′-dihydroxybiphenyl 298 g (1.6 mol) ), 199 g (1.2 mol) of terephthalic acid, 67 g (0.4 mol) of isophthalic acid, and 1714 g (8.0 mol) of diphenyl carbonate. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 200 ° C. over 15 minutes under a nitrogen gas stream, further raised to 220 ° C. over 30 minutes, and maintained at 220 ° C. for 3 minutes. Reflux for hours.
Thereafter, 1.3 g of 1-methylimidazole was added, and the temperature was raised to 340 ° C. over 100 minutes while distilling off the by-product phenol to be distilled and unreacted diphenyl carbonate, and 2 hours passed at 340 ° C. The reaction was considered to be complete and the contents were taken out. The obtained solid was cooled to room temperature, pulverized with a coarse pulverizer, heated from room temperature to 250 ° C. over 1 hour in a nitrogen atmosphere, heated from 250 ° C. to 261 ° C. over 5 hours, 261 The polymerization reaction was performed in a solid layer by maintaining at 3 ° C. for 3 hours. When the liquid crystallinity of the obtained resin was measured with a polarizing microscope, it was a liquid crystalline polyester that forms a melt phase having optical anisotropy.
The obtained resin was mixed with 40% by weight of Asahi Glass milled glass (REV-8) and mixed, and then granulated at 340 ° C. using a twin screw extruder (Ikegai Iron Works Co., Ltd. PCM-30). The obtained pellets are injection molded at a cylinder temperature of 350 ° C. and a mold temperature of 130 ° C. using a PS40E5ASE injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., and the characteristics of the resin (deflection temperature under load, amount of generated gas) are obtained. evaluated. The results are shown in Table 1.

Reference example 1
A resin was obtained in the same manner as in Example 1 except that N, N-dimethylaminopyridine was used instead of 1-methylimidazole and the conditions for solid-phase polymerization were changed to those shown in Table 1, and each measurement was performed. The results are shown in Table 1.
Moreover, when liquid crystallinity was measured about the obtained resin with the polarization microscope, it was liquid crystalline polyester which forms the melt phase which has optical anisotropy similarly to Example 1. FIG.

Reference example 2
Resin was obtained in the same manner as in Example 1 except that tetrabutoxytitanium was used in place of 1-methylimidazole and the solid-phase polymerization conditions were changed to those described in Table 1, and each measurement was performed. The results are shown in Table 1.
Moreover, when liquid crystallinity was measured about the obtained resin with the polarization microscope, it was liquid crystalline polyester which forms the melt phase which has optical anisotropy similarly to Example 1. FIG.

Comparative Example 1
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, p-hydroxybenzoic acid 911 g (6.6 mol), 4,4′-dihydroxybiphenyl 409 g (2.2 mol) ), 274 g (1.65 mol) of terephthalic acid, 91 g (0.55 mol) of isophthalic acid and 1235 g (12.1 mol) of acetic anhydride. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream, and the temperature was maintained and refluxed for 3 hours.
Thereafter, the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off distilling by-product acetic acid and unreacted acetic anhydride, and the time when an increase in torque was observed was regarded as completion of the reaction, and the contents were taken out. . The obtained solid content was cooled to room temperature, pulverized with a coarse pulverizer, heated from room temperature to 250 ° C. over 1 hour in a nitrogen atmosphere, heated from 250 ° C. to 280 ° C. over 5 hours, and 280 The polymerization reaction was performed in a solid layer by maintaining at 3 ° C. for 3 hours.
The obtained resin was mixed and mixed with 40% by weight of central glass milled glass (EFH-7501), and granulated at 340 ° C. using a twin screw extruder (Ikegai Iron Works Co., Ltd. PCM-30). The obtained pellets were injection molded at a cylinder temperature of 350 ° C. and a mold temperature of 130 ° C. using a PS40E5ASE type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., and resin properties (tensile strength, impact strength, deflection temperature under load) ) Was evaluated. The results are shown in Table 1.

ＰＨＢＡ：ｐ―ヒドロキシ安息香酸
ＤＨＢ：４，４’−ジヒドロキシビフェニル
ＴＰ：テレフタル酸
ＩＰ：イソフタル酸
１MI：１−メチルイミダゾール
DMAP：N,N-ジメチルアミノピリジン
Ti(OBu)4：テトラブトキシチタン

PHBA: p-hydroxybenzoic acid
DHB: 4,4′-dihydroxybiphenyl TP: terephthalic acid IP: isophthalic acid 1MI: 1-methylimidazole
DMAP: N, N-dimethylaminopyridine
Ti (OBu) 4: Tetrabutoxy titanium

It is sectional drawing of a thin wall flow length measurement metal mold | die. The thickness of the molded product obtained by this mold is 0.3 mm.

Explanation of symbols

1 sprue 2 runner (Φ4.0mm)
3 Gate (0.3t x 1.5w x 2.0l)
4 cavities

Claims (3)

An aromatic hydroxycarboxylic acid represented by the following formula (I), an aromatic diol represented by the following formula (II), an aromatic dicarboxylic acid represented by the following formula (III), an aromatic diol (II) and Diaryl carbonates represented by the following formula (IV) are used as esterification reagents in the presence of the following (a) so that the molar ratio with the aromatic dicarboxylic acid (III) is 90/100 to 100/90. A method for producing a liquid crystalline polyester comprising: performing melt polymerization, solidifying and pulverizing the liquid crystalline polyester produced by the melt polymerization to obtain a liquid crystalline polyester powder, and solid-phase polymerizing the liquid crystalline polyester powder .
HO-R ₁ -COOH (I)
HO-R ₂ -OH (II)
HOOC-R ₃ -COOH (III)

(IV)
Wherein R ₁ and R ₃ represent an optionally substituted arylene group, and R ₂ represents an optionally substituted arylene group or the following formula (V)

(V)
R _{4 to} R ₇ each independently represents a hydrogen atom or a halogen atom, an acyloxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, and X represents , -O -, - S -, - SO 2 -, - CO -, - represents an or an alkylene group - C ₆ H _10. )
(A) Imidazole compound represented by the following formula (VI)

(VI)
(Wherein R _{8 to} R ₁₁ each independently represent a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a cyano group, a cyanoalkyl group having 2 to 5 carbon atoms, or 2 carbon atoms) -5 represents a cyanoalkoxy group, a carboxyl group, an amino group, an aminoalkyl group having 1 to 4 carbon atoms, an aminoalkoxy group having 1 to 4 carbon atoms, a phenyl group, a benzyl group, a phenylpropyl group, or a formyl group. The aromatic hydroxycarboxylic acid (I) is 30 to 80 mol% based on the total of the aromatic hydroxycarboxylic acid (I), the aromatic diol (II) and the aromatic dicarboxylic acid (III). Manufacturing method. A liquid crystalline polyester obtained by the production method according to claim 1.

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