JPH051138A - Production of thermotropic liquid crystalline polyester - Google Patents

Abstract

PURPOSE:To produce a thermotropic liquid crystalline polyester excellent in thermal resistance, fluidity and uniformity by polycondensing a specified ester monomer with an equivalent amount of an aromatic dicarboxylic acid compound. CONSTITUTION:(A) An ester monomer of formula I is polycondensed with (B) an equivalent amount of an aromatic dicarboxylic acid compound [R<1> is 1-15C aliphatic hydrocarbon; Ar<1> and Ar<2> are 6-18C aromatic hydrocarbon; X<1> is H or R<2>-CO (R<2> is 1-6C hydrocarbon); X<2> and X<3> are H or 1-10C hydrocarbon] of formula II to obtain the objective thermotropic liquid crystalline polyester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a thermotropic liquid crystalline polyester (hereinafter referred to as a liquid crystalline polyester). In particular, the present invention relates to a liquid crystalline polyester having excellent heat resistance, fluidity and uniformity.

[0002]

2. Description of the Related Art In recent years, with the development of electric / electronic fields and automobile fields, demands for higher performance of plastics have increased, and many plastics have been developed and provided to the market. Among them, a group of polymer compounds that exhibit optical anisotropy when melted and whose molecular chains are arranged in parallel are called thermotropic liquid crystalline polymers, which are excellent in moldability and improve the mechanical properties of the molded body. It's getting a lot of attention. A typical example of the liquid crystalline polyester is a copolyester composed only of an ester bond of a polyethylene terephthalate unit and a parahydroxybenzoic acid unit [WJ Jackson]
, Journal of Polymer Science, Chemical
Edition (J.Polym.Sci.Polym.Chem.Ed.) Volume 14, 2043
Page (1976), U.S. Pat. No. 3,804,805, Japanese Patent Publication No. 56-18016
No. In the above-mentioned JP-B-56-18016, a polyethylene terephthalate unit and paraacetoxybenzoic acid (hereinafter referred to as p-ABA) are mixed to give a mixture of 240 to 30.
Although a method of producing a liquid crystalline polyester by heating at 0 ° C. is described, in this method,
When the p-ABA component is 75 mol% or more, p-AB
There is a problem that a polymer, which is considered to be generated by the block-wise polymerization of A, is mixed as an insoluble and infusible foreign substance, the liquidity of the obtained liquid crystalline polyester is deteriorated, and the moldability is deteriorated. This foreign substance is generated because a large amount of insoluble substance is present when dissolved in phenol / 1,1,2,2-tetrachloroethane = 1/1 (volume ratio), which is a good solvent for this type of polymer. Come up again.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a uniform liquid crystalline polyester having excellent heat resistance and fluidity.

[0004]

Means for Solving the Problems That is, according to the present invention, an ester monomer represented by the following general formula [I] and an aromatic dicarboxylic acid compound represented by the general formula [II] are polycondensed in substantially equivalent amounts. The present invention provides a method for producing a thermotropic liquid crystalline polyester.

[0005]

[Chemical 2]

[In the formula, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 15 carbon atoms, and X ¹ is A hydrogen atom or a group represented by R ² —CO— (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), X ² and X ³ are each independently a hydrogen atom or 1 to 10 carbon atoms. Is a hydrocarbon group. ]

R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, specifically, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene. Group, decylene group,
It is an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, or a pentadecylene group, and may have a straight chain, a branched chain or a ring. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group having 6 to 15 carbon atoms, and specific examples thereof include a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group and a terphenylene group. Is an alkyl group, an alkoxy group,
It may have a phenyl group, a halogen atom or the like as a substituent.

X ¹ is a hydrogen atom or a group represented by R ² --CO-- (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), specifically, a hydrogen atom or a methylcarbonyl group. , Ethylcarbonyl group, n-propylcarbonyl group,
i-propylcarbonyl group, n-butylcarbonyl group,
i-butylcarbonyl group, t-butylcarbonyl group, 1
Examples thereof include a methylethylcarbonyl group, a pentylcarbonyl group (having a linear or branched chain), a hexylcarbonyl group (having a linear, cyclic or branched chain) and a phenylcarbonyl group. X ² and X ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and specific examples of the hydrocarbon include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. It is a group, a heptyl group, an octyl group, a nonyl group, or a decyl group, and may have a linear, cyclic, or branched chain.

(Components) Ester Monomer [I] The ester monomer represented by the general formula [I] is a diol compound represented by the following general formula [III] and an aromatic carboxylic acid compound represented by the general formula [IV]. Can be prepared by any method which is purposeful for ester bond formation.

[0010]

[Chemical 3]

[Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and X ⁴ , X ⁵ and X ⁶ are Each independently a hydrogen atom or R ² —CO— (wherein R ² has 1 to 6 carbon atoms;
X ⁷ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. In this case, as the diol of [III], ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, 2-
Butene-1,4-diol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol,
Fatty acid diols such as 1,10-decanediol and 1,
Examples thereof include alicyclic diols such as 4-cyclohexanedimethanol and tricyclodecanedimethanol.

The aromatic carboxylic acid compound represented by the general formula [IV] used in the synthesis of the ester monomer is a hydroxyaromatic carboxylic acid or its ester, or an acyloxy aromatic carboxylic acid or its ester. Examples of the acyloxy aromatic carboxylic acid of [IV] include p-acetoxybenzoic acid, p-propionoxybenzoic acid, p-butyroxybenzoic acid, p-valeroxybenzoic acid, p-caproxybenzoic acid, 2-acetoxy-6-
Naphthoic acid, 4'-acetoxybiphenylcarboxylic acid and the like can be mentioned. The position of the hydroxyl group or the acyloxy group may be ortho, meta or para, but the para position is particularly preferable.

In the synthesis of the ester monomer [I], for example, a method of directly esterifying a diol compound represented by the general formula [III] and an aromatic carboxylic acid compound represented by the general formula [IV], a general formula [ III) and at least one of the aromatic carboxylic acid compounds represented by the general formula [IV] are reacted in the form of their functional derivatives. Examples of the latter method include the case where an aromatic carboxylic acid is converted to an acid halide (for example, an acid chloride) and reacted with a diol, or the hydroxyl group of a diol compound is reacted with an aromatic carboxylic acid in the form of its acyl derivative, and In some cases, an aromatic carboxylic acid is reacted with a hydroxyl group in the form of an ester derivative. For example, when a diol is used as the diol compound represented by the general formula [III] and an acyloxy aromatic carboxylic acid is used as the aromatic carboxylic acid compound represented by the general formula [IV], the acyloxy aromatic carboxylic acid is used as an acid chloride. The ester monomer can be produced by reacting the diol with a molar ratio of about 2 times and dehydrochlorinating. When the ester monomer of [I] is produced from the diol represented by [III] and the aromatic carboxylic acid represented by [IV], X ^{1 of} [I] is the same as X ^{6 of} [IV]. ..

Aromatic Dicarboxylic Acid Compound [II] The aromatic dicarboxylic acid compound represented by the general formula [II] used in the present invention is an aromatic dicarboxylic acid or an aromatic dicarboxylic acid monoester or diester.
Ar ² is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and specific examples thereof include a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group, and a terphenylene group.
These may have an alkyl group, an alkoxy group, a phenyl group, a halogen atom or the like as a substituent. Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid.

(Production of Liquid Crystalline Polyester) In the present invention, an ester monomer represented by the general formula [I],
A liquid crystalline polyester is produced by polycondensation with an aromatic dicarboxylic acid compound represented by the general formula [II]. The amount of the aromatic dicarboxylic acid compound [II] used is substantially equivalent to the ester monomer [I]. That is, the molar ratio is [I] / [II] = 0.9 to 1.1, preferably,
The range is 0.95 to 1.05.

In the polymerization reaction, raw materials (ester monomer [I] and aromatic dicarboxylic acid compound [II]) are charged, and the reaction temperature is 200 to 350 ° C., preferably 250 to 350 ° C.
It is performed at 325 ° C. The reaction may be carried out by charging the whole amount at the same time, but the aromatic dicarboxylic acid may be sequentially added to the ester monomer. The reaction time depends on the reaction temperature, but for example, the reaction temperature is
It takes about 7 hours to gradually raise the temperature from 50 ° C to 325 ° C. The polymerization reaction is preferably carried out under an inert gas stream. Nitrogen, argon, etc. can be used as the inert gas, and it is preferable to continuously introduce them into the system. As the polycondensation reaction proceeds, the compounds represented by the following general formulas [V] and [VI] are eliminated.

[0017]

[Chemical 4]

These compounds are distilled out of the stoichiometric system. In this case, it is preferable to finally carry out the reaction under reduced pressure from the viewpoint of reaction time and the like. Specifically, 1 mm at the end of the reaction
The reaction is performed at a vacuum degree of Hg or less for about 1 hour, and more preferably, subsequently, for about 0.5 hour at a vacuum degree of 0.1 mmHg or less. The liquid crystalline polymer produced according to the present invention should have a sufficiently large molecular weight. This liquid crystalline polymer has an intrinsic viscosity of 0.1 measured with a solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (or pentafluorophenol or parachlorophenol).
It is 2 or more, preferably 0.4 or more. The liquid crystal starting temperature is preferably 160 ° C. or higher.

The liquid crystalline polymer produced according to the present invention has a molar ratio of p-hydroxybenzoic acid structural units (corresponding to Ar ¹ ) to the total number of moles of aromatic groups (corresponding to Ar ¹ + Ar ² ) of about 67 mol. Account for%. The liquid crystalline polyester of the present invention can be subjected to usual melt molding such as injection molding, extrusion molding, compression molding and blow molding, and can be processed into three-dimensional molded products, films, fibers, containers and the like. .. Further, a polymer alloy can also be obtained by mixing with another thermoplastic resin. At the time of molding, the liquid crystalline polyester of the present invention is added with additives such as a reinforcing agent such as glass fiber and carbon fiber, a filler, an antioxidant, a stabilizer, a plasticizer and a release agent to obtain a molded product. Can be provided with desired characteristics.

[0020]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The intrinsic viscosity, the thermal weight loss onset temperature (TGA), the flow onset temperature and the liquid crystallinity of the copolyester were determined as follows. (1) Intrinsic viscosity: phenol / 1,1,2,2-tetrachloroethane = 1/1 (weight ratio) in a mixed solvent at 30 ° C
It was measured at. For those that do not dissolve under the above conditions,
Pentafluorophenol (referred to as PFP in the table below) or parachlorophenol (p in the table below)
-ChP) at 50 ° C. (2) Thermogravimetric reduction start temperature (TGA): SEIKO I
Using TG / DTA20 manufactured by & E, measurement was performed in nitrogen at a heating rate of 10 ° C./min. (3) Flow starting temperature and liquid crystallinity: Confirmed with a polarizing microscope equipped with a hot stage.

Reference Example 1 Synthesis of p-acetoxybenzoic acid chloride To 500 ml of thionyl chloride, 180.16 g (1.0 mol) of p-acetoxybenzoic acid was added, and 1 ml of dimethylformamide (DMF) was added dropwise as a catalyst and stirred. When the generation of hydrogen chloride and sulfur dioxide stopped and the reaction solution became transparent, p-acetoxybenzoic acid was added to 180.
16 g (1.0 mol) each over 5 times in total (6.0 mol
l) added. After the addition of all 6.0 mol, the generation of hydrogen chloride and sulfur dioxide stopped, and when the reaction solution became transparent, reflux was carried out for 3 hours. Then, the product was purified by distillation (173 ° C, 10 mmHg).

Reference Example 2 Cyclohexanedimethanol ester monomer [I]
Synthesis of cyclohexanedimethanol 194.684 g (1.35)
mol), pyridine (242.64 ml, 3.0 mol) and acetone (1000 ml) were cooled to 20 ° C. or lower under an argon stream. Into this, p-acetoxybenzoic acid chloride 595.8
21 g (3.0 mol) was added dropwise, taking care not to let the reaction temperature exceed 20 ° C. 2 hours at room temperature after dropping, 60
After stirring for 2 hours at ℃, the mixture was allowed to stand, poured into distilled water and filtered. The crystals on the filter paper were washed twice with water and twice with methanol and then dried, recrystallized from dioxane, filtered and dried, and 545.21 g (1.164 g) of cyclohexane ester monomer was obtained.
mol, 86.2%) was obtained.

(Reference Example 3) Synthesis of ester monomer [I] of ethylene glycol 27.932 g (0.45 mol) of ethylene glycol, 80.88 ml of pyridine and 500 ml of acetone were cooled to 20 ° C or lower under an argon stream. To this, 198.607 g (1.0 mol) of p-acetoxybenzoic acid chloride was added dropwise while being careful not to let the temperature of the reaction solution exceed 20 ° C.
After the dropping, the mixture was stirred at room temperature for 2 hours and at 60 ° C. for 2 hours, and allowed to stand,
It was poured into distilled water and separated. The solvent was distilled off from the upper organic layer, and the obtained crystals were recrystallized from methanol, filtered and dried, and ethylene glycol ester monomer 140.
Obtained 06 g (0.36 mol, 80.56%).

(Reference Example 4) Synthesis of ester monomer [I] of butanediol 40.554 g (0.45 mol) of butanediol, 80.88 ml of pyridine and 500 ml of acetone were added under an argon stream to 2
It was cooled to below 0 ° C. 198.607 g (1.0 mol) of p-acetoxybenzoic acid chloride was added dropwise thereto while being careful not to let the temperature of the reaction solution exceed 20 ° C. After the dropping, the mixture was stirred at room temperature for 2 hours and at 60 ° C. for 2 hours and then allowed to stand, and distilled water was poured thereinto and filtered. The crystals on the filter paper were washed twice with water and twice with methanol and then dried, recrystallized from methanol, filtered and dried, and the butanediol ester monomer was added to 15 times.
8.51 g (0.38 mol, 85.00%) was obtained.

Example 1 93.70 g (0.2 mol) of the ester monomer of cyclohexanedimethanol prepared in Reference Example 2 and 33.228 g (0.20 mol) of terephthalic acid were mixed with a stirrer, a thermometer, a distilling pipe, and argon was introduced. A 300 ml separable flask equipped with a tube was charged. After purging with argon three times, the metal bath was heated to 200 ° C. and heated for 30 minutes to melt the contents. Stirring is started, and the metal bath is heated to 250 ° C for 2 hours, then 275 ° C for 2 hours, and 300 ° C for 2 hours, 32
After reacting at 5 ° C for 1 hour, the theoretical amount of acetic acid (22.9 ml)
About 90% (20.0 ml) was distilled. Furthermore, 325 ° C
The pressure was reduced to 1 mmHg or less and the pressure was reduced for 30 minutes to distill the theoretical amount of acetic acid. After the polymerization was completed, the contents were taken out from the separable flask while it was hot. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.377, a flow starting temperature of 270 ° C., and TGA.
Was 391.3 ° C. The infrared spectroscopic spectrum of the obtained liquid crystal polymer is shown in FIG.

Example 2 A liquid crystalline polymer was prepared in the same manner as in Example 1 except that the ester monomer of cyclohexanedimethanol was changed to 77.272 g (0.2 mol) of the ester monomer of ethylene glycol produced in Reference Example 3. Obtained. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.363, a flow starting temperature of 170 ° C., and a TG
A was 413.4 ° C.

Example 3 Example 1 was repeated except that the ester monomer of cyclohexanedimethanol was changed to 82.883 g (0.2 mol) of the ester monomer of butanediol prepared in Reference Example 4.
A liquid crystal polymer was obtained in the same manner as in. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.225 (p-ChP) and a flow starting temperature of 2
At 60 ° C the TGA was 378.0 ° C.

Comparative Example To prepare a liquid crystalline polyester having the same composition as in Example 3, 73.41 g (0.33 g) of polybutylene terephthalate was prepared.
3 mol) and 120.11 g (0.667 mol) of p-ABA were equipped with a stirrer, thermometer, distilling tube, and argon introducing tube.
A 00 ml separable flask was charged. 3 with Argon
After substituting twice, the metal bath was heated to 200 ° C. and heated for 30 minutes to melt the contents. Then, stirring was started, the metal bath was set to 250 ° C. for 2 hours, and then at 275 ° C. for about 1 hour, a white solid began to precipitate. I tried to measure the intrinsic viscosity of this white solid.
It was insoluble in a mixed solvent of 2-tetrachloroethane = 1/1 (weight ratio), p-chlorophenol and pentafluorophenol, and the intrinsic viscosity could not be measured.

[0029]

According to the production method of the present invention, it is possible to provide a liquid crystalline polyester having high uniformity, excellent fluidity, and excellent heat resistance.

[Brief description of drawings]

1 of the liquid crystal polymer obtained in Example 1 of the present invention,
It is a figure which shows an infrared spectroscopy spectrum.

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[Procedure amendment]

[Submission date] February 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for producing thermotropic liquid crystalline polyester

[Claims]

[Chemical 1] [In the formula, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 18 carbon atoms, and X ¹ is a hydrogen atom or R ² −
CO- (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), X ² and X ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. is there〕.

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a thermotropic liquid crystalline polyester (hereinafter referred to as a liquid crystalline polyester). In particular, the present invention relates to a liquid crystalline polyester having excellent heat resistance, fluidity and uniformity.

[0002]

2. Description of the Related Art In recent years, with the development of electric / electronic fields and automobile fields, demands for higher performance of plastics have increased, and many plastics have been developed and provided to the market. Among them, a group of polymer compounds that exhibit optical anisotropy when melted and whose molecular chains are arranged in parallel are called thermotropic liquid crystalline polymers, which are excellent in moldability and improve the mechanical properties of the molded body. It's getting a lot of attention. A typical example of the liquid crystalline polyester is a copolyester composed only of an ester bond of a polyethylene terephthalate unit and a parahydroxybenzoic acid unit [WJ Jackson]
, Journal of Polymer Science, Chemical
Edition (J.Polym.Sci.Polym.Chem.Ed.) Volume 14, 2043
Page (1976), U.S. Pat. No. 3,804,805, Japanese Patent Publication No. 56-18016
No. In the above-mentioned JP-B-56-18016, a polyethylene terephthalate unit and paraacetoxybenzoic acid (hereinafter referred to as p-ABA) are mixed to give a mixture of 240 to 30.
Although a method of producing a liquid crystalline polyester by heating at 0 ° C. is described, in this method,
When the p-ABA component is 75 mol% or more, p-AB
There is a problem that a polymer that is considered to be generated by block-wise polymerization of A is mixed as an insoluble and infusible foreign matter, the liquidity of the obtained liquid crystalline polyester is deteriorated, and the moldability is deteriorated (Comparative Example). 2) . The generation of this foreign substance is caused by good solvent of this type of polymer: phenol / 1,1,2,2-tetrachloroethane = 1/1
It can also be seen from the fact that a large amount of insoluble substance exists when dissolved in (volume ratio).

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a uniform liquid crystalline polyester having excellent heat resistance and fluidity.

[0004]

Means for Solving the Problems That is, according to the present invention, an ester monomer represented by the following general formula [I] and an aromatic dicarboxylic acid compound represented by the general formula [II] are polycondensed in substantially equivalent amounts. The present invention provides a method for producing a thermotropic liquid crystalline polyester.

[0005]

[Chemical 2]

[Wherein R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 18 carbon atoms, and X ¹ is A hydrogen atom or a group represented by R ² —CO— (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), X ² and X ³ are each independently a hydrogen atom or 1 to 10 carbon atoms. Is a hydrocarbon group. ]

R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, specifically, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene. Group, decylene group,
It is an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, or a pentadecylene group, and may have a straight chain, a branched chain or a ring. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group having 6 to 15 carbon atoms, and specific examples thereof include a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group and a terphenylene group. Is an alkyl group, an alkoxy group,
It may have a phenyl group, a halogen atom or the like as a substituent.

X ¹ is a hydrogen atom or a group represented by R ² --CO-- (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), specifically, a hydrogen atom or a methylcarbonyl group. , Ethylcarbonyl group, n-propylcarbonyl group,
i-propylcarbonyl group, n-butylcarbonyl group,
i-butylcarbonyl group, t-butylcarbonyl group, 1
Examples thereof include a methylethylcarbonyl group, a pentylcarbonyl group (having a linear or branched chain), a hexylcarbonyl group (having a linear, cyclic or branched chain) and a phenylcarbonyl group. X ² and X ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and specific examples of the hydrocarbon include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. It is a group, a heptyl group, an octyl group, a nonyl group, or a decyl group, and may have a linear, cyclic, or branched chain.

(Components) Ester Monomer [I] The ester monomer represented by the general formula [I] is a diol compound represented by the following general formula [III] and an aromatic carboxylic acid compound represented by the general formula [IV]. Can be prepared by any method which is purposeful for ester bond formation.

[0010]

[Chemical 3]

[Wherein, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and X ⁴ , X ⁵ and X ⁶ are Each independently a hydrogen atom or R ² —CO— (wherein R ² has 1 to 6 carbon atoms;
X ⁷ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. In this case, as the diol of [III], ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, 2-
Butene-1,4-diol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol,
Fatty acid diols such as 1,10-decanediol and 1,
Examples thereof include alicyclic diols such as 4-cyclohexanedimethanol and tricyclodecanedimethanol.

The aromatic carboxylic acid compound represented by the general formula [IV] used in the synthesis of the ester monomer is a hydroxyaromatic carboxylic acid or its ester, or an acyloxy aromatic carboxylic acid or its ester. Examples of the acyloxy aromatic carboxylic acid of [IV] include p-acetoxybenzoic acid, p-propionoxybenzoic acid, p-butyroxybenzoic acid, p-valeroxybenzoic acid, p-caproxybenzoic acid, 2-acetoxy-6-
Naphthoic acid, 4'-acetoxybiphenylcarboxylic acid and the like can be mentioned. The position of the hydroxyl group or the acyloxy group may be ortho, meta or para, but the para position is particularly preferable.

In the synthesis of the ester monomer [I], for example, a method of directly esterifying a diol compound represented by the general formula [III] and an aromatic carboxylic acid compound represented by the general formula [IV], a general formula [ III) and at least one of the aromatic carboxylic acid compounds represented by the general formula [IV] are reacted in the form of their functional derivatives. Examples of the latter method include the case where an aromatic carboxylic acid is converted to an acid halide (for example, an acid chloride) and reacted with a diol, or the hydroxyl group of a diol compound is reacted with an aromatic carboxylic acid in the form of its acyl derivative, and In some cases, an aromatic carboxylic acid is reacted with a hydroxyl group in the form of an ester derivative. For example, when a diol is used as the diol compound represented by the general formula [III] and an acyloxy aromatic carboxylic acid is used as the aromatic carboxylic acid compound represented by the general formula [IV], the acyloxy aromatic carboxylic acid is used as an acid chloride. The ester monomer can be produced by reacting the diol with a molar ratio of about 2 times and dehydrochlorinating. When the ester monomer of [I] is produced from the diol represented by [III] and the aromatic carboxylic acid represented by [IV], X ^{1 of} [I] is the same as X ^{6 of} [IV]. ..

Aromatic Dicarboxylic Acid Compound [II] The aromatic dicarboxylic acid compound represented by the general formula [II] used in the present invention is an aromatic dicarboxylic acid or an aromatic dicarboxylic acid monoester or diester.
Ar ² is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and specific examples thereof include a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group, and a terphenylene group.
These may have an alkyl group, an alkoxy group, a phenyl group, a halogen atom or the like as a substituent. Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid.

(Production of Liquid Crystalline Polyester) In the present invention, an ester monomer represented by the general formula [I],
A liquid crystalline polyester is produced by polycondensation with an aromatic dicarboxylic acid compound represented by the general formula [II]. The amount of the aromatic dicarboxylic acid compound [II] used is substantially equivalent to the ester monomer [I]. That is, the molar ratio is [I] / [II] = 0.9 to 1.1, preferably,
The range is 0.95 to 1.05.

In the polymerization reaction, raw materials (ester monomer [I] and aromatic dicarboxylic acid compound [II]) are charged, and the reaction temperature is 200 to 350 ° C., preferably 250 to 350 ° C.
It is performed at 325 ° C. In the reaction, the whole amount may be charged at the same time for the reaction, and the aromatic dicarboxylic acid may be sequentially added to the ester monomer. Although the reaction time varies depending on the reaction temperature, for example, the reaction temperature is set to 2
It takes about 7 hours to gradually raise the temperature from 50 ° C to 325 ° C. The polymerization reaction is preferably carried out under an inert gas stream. Nitrogen, argon, etc. can be used as the inert gas, and it is preferable to continuously introduce them into the system. As the polycondensation reaction proceeds, the compounds represented by the following general formulas [V] and [VI] are eliminated.

[0017]

[Chemical 4]

These compounds are distilled out of the stoichiometric system. In this case, it is preferable to finally carry out the reaction under reduced pressure from the viewpoint of reaction time and the like. Specifically, 1 mm at the end of the reaction
The reaction is performed at a vacuum degree of Hg or less for about 1 hour, and more preferably, subsequently, for about 0.5 hour at a vacuum degree of 0.1 mmHg or less. The liquid crystalline polymer produced according to the present invention should have a sufficiently large molecular weight. This liquid crystalline polymer has an intrinsic viscosity of 0.1 measured with a solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (or pentafluorophenol or parachlorophenol).
It is 2 or more, preferably 0.4 or more. The flow starting temperature is preferably 160 ° C or higher.

The liquid crystalline polymer produced according to the present invention has a molar ratio of p-hydroxybenzoic acid structural units (corresponding to Ar ¹ ) to the total number of moles of aromatic groups (corresponding to Ar ¹ + Ar ² ) of about 67 mol. Account for%. The liquid crystalline polyester of the present invention can be subjected to usual melt molding such as injection molding, extrusion molding, compression molding and blow molding, and can be processed into three-dimensional molded products, films, fibers, containers and the like. .. Further, a polymer alloy can also be obtained by mixing with another thermoplastic resin. At the time of molding, the liquid crystalline polyester of the present invention is added with additives such as a reinforcing agent such as glass fiber and carbon fiber, a filler, an antioxidant, a stabilizer, a plasticizer and a release agent to obtain a molded product. Can be provided with desired characteristics.

[0020]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The intrinsic viscosity, the thermal weight loss onset temperature (TGA), the flow onset temperature and the liquid crystallinity of the copolyester were determined as follows. (1) Intrinsic viscosity: phenol / 1,1,2,2-tetrachloroethane = 1/1 (weight ratio) in a mixed solvent at 30 ° C
It was measured at. For those that do not dissolve under the above conditions,
Pentafluorophenol (referred to as PFP in the table below) or parachlorophenol (p in the table below)
-ChP) and the logarithmic viscosity measured at 50 ° C in
It was However, the horizontal line in the table is soluble in any of the above solvents
Indicates that you did not . (2) Thermogravimetric reduction start temperature (TGA): SEIKO I
Using TG / DTA20 manufactured by & E, measurement was performed in nitrogen at a heating rate of 10 ° C./min. (3) Flow starting temperature and liquid crystallinity: Confirmed with a polarizing microscope equipped with a hot stage.

Reference Example 1 p-acetoxybenzoic acid
Synthesis of Loride To 500 ml of thionyl chloride, 180.16 g (1.0 mol) of p-acetoxybenzoic acid was added, and 1 ml of dimethylformamide (DMF) was added dropwise as a catalyst and stirred, and the generation of hydrogen chloride and sulfur dioxide stopped and the reaction solution became When it became transparent, 180 more p-acetoxybenzoic acid was added.
16 g (1.0 mol) each over 5 times in total (6.0 mol
l) added. After the addition of all 6.0 mol, the generation of hydrogen chloride and sulfur dioxide stopped, and when the reaction solution became transparent, reflux was carried out for 3 hours. Then, the product was purified by distillation (173 ° C, 10 mmHg).

Reference Example 2 Cyclohexanedimethanoe
Synthesis of ester monomer [I] of cyclohexanedimethanol 194.684 g (1.35)
mol), pyridine (242.64 ml, 3.0 mol) and acetone (1000 ml) were cooled to 20 ° C. or lower under an argon stream. Into this, p-acetoxybenzoic acid chloride 595.8
21 g (3.0 mol) was added dropwise, taking care not to let the reaction temperature exceed 20 ° C. 2 hours at room temperature after dropping, 60
After stirring for 2 hours at ℃, the mixture was allowed to stand, poured into distilled water and filtered. The crystals on the filter paper were washed twice with water and twice with methanol and then dried, recrystallized from dioxane, filtered and dried, and 545.21 g (1.164 g) of cyclohexane ester monomer was obtained.
mol, 86.2%) was obtained.

(Reference Example 3) Ethylene glycol s
Synthesis of Termonomer [I] 27.932 g (0.45 mol) of ethylene glycol, 80.88 ml of pyridine and 500 ml of acetone were cooled to 20 ° C. or lower under an argon stream. To this, 198.607 g (1.0 mol) of p-acetoxybenzoic acid chloride was added dropwise while being careful not to let the temperature of the reaction solution exceed 20 ° C.
After the dropping, the mixture was stirred at room temperature for 2 hours and at 60 ° C. for 2 hours, and allowed to stand,
It was poured into distilled water and separated. The solvent was distilled off from the upper organic layer, and the obtained crystals were recrystallized from methanol, filtered and dried, and ethylene glycol ester monomer 140.
Obtained 06 g (0.36 mol, 80.56%).

Reference Example 4 Butanediol Ester
Synthesis of Monomer [I] Butanediol 40.554g (0.45mol), pyridine 80.88ml, acetone 500ml under argon flow
It was cooled to below 0 ° C. 198.607 g (1.0 mol) of p-acetoxybenzoic acid chloride was added dropwise thereto while being careful not to let the temperature of the reaction solution exceed 20 ° C. After the dropping, the mixture was stirred at room temperature for 2 hours and at 60 ° C. for 2 hours and then allowed to stand, and distilled water was poured thereinto and filtered. The crystals on the filter paper were washed twice with water and twice with methanol and then dried, recrystallized from methanol, filtered and dried, and the butanediol ester monomer was added to 15 times.
8.51 g (0.38 mol, 85.00%) was obtained.

Example 1 93.70 g (0.2 mol) of the ester monomer of cyclohexanedimethanol prepared in Reference Example 2 and 33.228 g (0.20 mol) of terephthalic acid were mixed with a stirrer, a thermometer, a distilling pipe, and argon was introduced. A 300 ml separable flask equipped with a tube was charged. After purging with argon three times, the metal bath was heated to 200 ° C. and heated for 30 minutes to melt the contents. Stirring is started, and the temperature of the metal bath is 250 ° C. for 2 hours, then 275 ° C. for 2 hours and 300 ° C. for 2 hours, 32 hours.
After reacting at 5 ° C for 1 hour, the theoretical amount of acetic acid (22.9 ml)
About 90% (20.0 ml) was distilled. Furthermore, 325 ° C
The pressure was reduced to 1 mmHg or less and the pressure was reduced for 30 minutes to distill the theoretical amount of acetic acid. After the polymerization was completed, the contents were taken out from the separable flask while it was hot. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.377, a flow starting temperature of 270 ° C., and TGA.
Was 391.3 ° C. The infrared spectroscopic spectrum of the obtained liquid crystal polymer is shown in FIG.

Example 2 A liquid crystalline polymer was prepared in the same manner as in Example 1 except that the ester monomer of cyclohexanedimethanol was changed to 77.272 g (0.2 mol) of the ester monomer of ethylene glycol produced in Reference Example 3. Obtained. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.363, a flow starting temperature of 170 ° C., and a TG
A was 413.4 ° C.

Example 3 Example 1 was repeated except that the ester monomer of cyclohexanedimethanol was changed to 82.883 g (0.2 mol) of the ester monomer of butanediol prepared in Reference Example 4.
A liquid crystal polymer was obtained in the same manner as in. Melting anisotropy of this polymer was confirmed by a polarizing microscope with a hot stage. This liquid crystalline polyester has an intrinsic viscosity [η] of 0.225 (p-ChP) and a flow starting temperature of 2
At 60 ° C the TGA was 378.0 ° C.

Comparative Example 1 In order to produce a liquid crystalline polyester having the same composition as in Example 3, 73.41 g (0.33 g) of polybutylene terephthalate was prepared.
3 mol) and 120.11 g (0.667 mol) of p-ABA were equipped with a stirrer, thermometer, distilling tube, and argon introducing tube.
A 00 ml separable flask was charged. 3 with Argon
After substituting twice, the metal bath was heated to 200 ° C. and heated for 30 minutes to melt the contents. Then, stirring was started, the metal bath was set to 250 ° C. for 2 hours, and then at 275 ° C. for about 1 hour, a white solid began to precipitate. I tried to measure the intrinsic viscosity of this white solid.
It was insoluble in a mixed solvent of 2-tetrachloroethane = 1/1 (weight ratio), p-chlorophenol and pentafluorophenol, and the intrinsic viscosity could not be measured.

COMPARATIVE EXAMPLE 2 Polyethylene terephthalate was placed in the same reactor as in Example 1.
63.99 g (0.333 mol) of p-acetoxy ammonium salt
Benzoic acid 120.11 g (0.667 mol) was charged.
After purging with argon three times, bring the metal bath to 200 ° C. and
The contents were melted by heating for 0 minutes. Then start stirring
The metal bath at 250 ° C for 2 hours and then at 275 ° C.
About 1 hour later, a white solid began to precipitate. This white
I tried to measure the intrinsic viscosity of a colored solid,
Mixing of 1,1,2,2-tetrachloroethane = 1/1 (weight ratio)
Solvent, p-chlorophenol, pentafluoropheno
It did not dissolve in the solvent and the intrinsic viscosity could not be measured. Well
In addition, at the flow starting temperature, insoluble substances were seen and
No liquid crystal phase was obtained.

[0030]

According to the production method of the present invention, it is possible to provide a liquid crystalline polyester having high uniformity, excellent fluidity, and excellent heat resistance.

[Brief description of drawings]

1 of the liquid crystal polymer obtained in Example 1 of the present invention,
It is a figure which shows an infrared spectroscopy spectrum.

Claims (1)

Claim: What is claimed is: 1. An ester monomer represented by the following general formula [I] and an aromatic dicarboxylic acid compound represented by the general formula [II] are polycondensed in substantially equivalent amounts. And a method for producing the thermotropic liquid crystalline polyester: [In the formula, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 15 carbon atoms, and X ¹ is a hydrogen atom or R ² −
CO- (wherein R ² is a hydrocarbon group having 1 to 6 carbon atoms), X ² and X ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. is there〕.