JPH05140282A - Preparation of thermotropic liquid crystalline polyester - Google Patents

Abstract

PURPOSE:To improve heat resistance, flowability, and homogeneity by polycondensing a specific ester monomer, an arom. dihydroxy compd., an arom. dicarboxylic acid compd., and an arom. hydroxy carboxylic acid compd. CONSTITUTION:An ester monomer (A) of formula I (wherein R<1> is 1-15C aliph. hydrocarbon group; Ar<1> is a 6-18C arom. hydrocarbon group; X<1> is H or R<2>-CO; and R<2> is a 1-6C hydrocarbon group), an arom. dihydroxy compd. (B) of formula II (wherein X<2> is X<1>; and Ar<2> is Ar<1>) in an amt. of 0.05-15 equivalents, an arom. dicarboxylic acid compd. (C) of formula III (wherein Y<1> is H or a 1-10C hydrocarbon group; and Ar<3> is Ar<1>) in a molar ratio of (A+B)/C of 0.9-1.1, and an arom. hydroxy carboxylic acid compd. (D) of formula IV (wherein X<3> is X<1>; Ar<4> is Ar<1>; and Y<2> is Y<1>) in a molar ratio of D/A of 0.1-17 are polycondensed at 200-350 deg.C to give the objective thermotropic liq. crystalline polyester having a logarithmic viscosity (in pentafluorophenol) of 1.0 or higher and a flow- beginning temp. of 180 deg.C or higher.

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). The liquid crystalline polyester produced according to the present invention has excellent heat resistance and excellent 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 consisting of an ester bond of a polyethylene terephthalate unit and a parahydroxybenzoic acid unit (WJ Jackson et al., J. Polym. Sci. Polym. Chem. E.
Volume 14, page 2043 (1976), U.S. Pat. No. 38
04805, JP-A-51-8395, etc.). In the above-mentioned Japanese Patent Laid-Open No. 51-8395, a polyethylene terephthalate unit and paraacetoxybenzoic acid (hereinafter referred to as p
-ABA) is mixed and polymerized by heating at 240 to 300 ° C to produce a liquid crystalline polyester. It is known that when the content of the p-ABA component is increased, the heat resistance of the liquid crystalline polyester is improved, but in this method, the p-ABA component is adjusted to 75 mol% or more of all aromatic groups in the polymer. If p-
There is a problem that a polymer that is considered to have been produced by ABA block-wise polymerizing is mixed as an insoluble and infusible foreign substance (Comparative Example 4), and the liquidity of the obtained liquid crystalline polyester is deteriorated and the moldability is deteriorated. there were. The generation of this foreign substance
This can also be seen from the presence of a large amount of insoluble substances when dissolved in a good solvent for this type of polymer.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is p-
An object of the present invention is to provide a method for producing a uniform liquid crystalline polyester which can contain a large amount of structural units of hydroxyaromatic carboxylic acid represented by ABA, has excellent heat resistance and fluidity.

[0005]

The present invention provides an ester monomer represented by the following general formula [I] and a general formula [I]
I], a dihydroxy aromatic compound, an aromatic dicarboxylic acid compound represented by the following general formula [III], and a hydroxyaromatic carboxylic acid compound represented by the following general formula [IV] are polycondensed. And a method for producing a thermotropic liquid crystalline polyester.

[0006]

[Chemical 2]

(Where R is¹Is an aliphatic charcoal having 1 to 15 carbon atoms
A hydrogenated group, Ar¹, Ar², Ar³And Ar^FourIs that
Each independently an aromatic hydrocarbon group having 6 to 18 carbon atoms, X
¹, X ²And X³ Are each independently a hydrogen atom or R²
-CO- (however, R²Is a hydrocarbon group having 1 to 6 carbon atoms
Is a group represented by¹And Y²Are independent
Is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms) R¹Is an aliphatic hydrocarbon group having 1 to 15 carbon atoms,
Specifically, methylene group, ethylene group, propylene group,
Tylene group, pentylene group, hexylene group, heptylene
Group, octylene group, nonylene group, decylene group, undecyl group
Ren group, dodecylene group, tridecylene group, tetradecyl group
Group and pentadecylene group, which may be linear or cyclic.
In addition, it may have a branched chain.

Ar¹, Ar², Ar³And Ar^FourAre each German
Is an aromatic hydrocarbon group having 6 to 18 carbon atoms,
Include phenylene group, naphthylene group, biphenylene group,
Examples thereof include anthrylene group and terphenylene group.
Alkyl group, alkoxyl group, phenyl group, halogen
It may have a hydrogen atom or the like as a substituent. X¹, X²
And X³ Are each independently a hydrogen atom or R²-CO-
(However, R ²Is a hydrocarbon group having 1 to 6 carbon atoms)
And specifically, a hydrogen atom, methylcarbo
Nyl group, ethylcarbonyl group, n-propylcarbonyl group
Group, i-propylcarbonyl group, n-butylcarbonyl
Group, i-butylcarbonyl group, t-butylcarbonyl
Group, 1-methylpropylcarbonyl group, pentylcarbo
Nyl group (having straight or branched chain), hexylca
Rubonyl group (having linear, cyclic or branched chain
), A phenylcarbonyl group and the like.

Y ¹ and Y ² are each independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 10 carbon atoms. Specific examples of the aliphatic hydrocarbon include a methyl group, an ethyl group,
A propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group, which may be linear or cyclic, or may have a branched chain.

Starting Material Ester Monomer The ester monomer represented by the general formula [I] is an ester monomer formed from a diol compound represented by the following general formula [V] and a hydroxyaromatic carboxylic acid compound represented by the general formula [IV]. Can be manufactured by any method that is purposeful. X ⁴ —O—R ¹ —O—X ⁵ [V] (In the formula, R ¹ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, and X ⁴ and X ⁵ are each independently a hydrogen atom or R ²
—CO— (wherein R ² is a group represented by a hydrocarbon group having 1 to 6 carbon atoms) X ⁴ and X ⁵ are each independently a hydrogen atom or R ² —C.
O- (provided that R ² is a hydrocarbon group having 1 to 6 carbon atoms)
And is specifically the same as the above X ¹ , X ² and X ³ .

Specific examples of the diol compound represented by the general formula [V] include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1 Chain diols such as 10-decanediol and alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol.

The hydroxyaromatic carboxylic acid compound represented by the general formula [IV] used for the synthesis of the ester monomer is a hydroxyaromatic carboxylic acid or its ester, or an acyloxyaromatic carboxylic acid or its ester. Specific examples thereof include p-hydroxybenzoic acid, p-acetoxybenzoic acid, p-propoxybenzoic acid, p-butyroxybenzoic acid, p-valeroxybenzoic acid, p-caproxybenzoic acid, 2-hydroxy-6.
-Naphthoic acid, 2-acetoxy-6-naphthoic acid, 4-
Examples thereof include hydroxy-4′-biphenylcarboxylic acid, 4-acetoxy-4′-biphenylcarboxylic acid and esters thereof. The position of the hydroxy group or the acyloxy group may be ortho, meta, or para,
Particularly preferred is the para position.

Specific examples of the method for producing the ester monomer include a method of directly esterifying a diol compound represented by the general formula [V] and a hydroxyaromatic carboxylic acid compound represented by the general formula [IV], and a general formula [ IV] and a method of reacting at least one of the hydroxyaromatic carboxylic acid compound represented by the general formula [IV] in the form of a functional derivative thereof, and the like. As a specific example of the latter method, a diol is used as the diol compound represented by the general formula [V] and an acyloxy aromatic carboxylic acid is used as the hydroxyaromatic carboxylic acid compound represented by the general formula [IV]. Aromatic carboxylic acid is used as acid chloride and diol and about 1: 2
The ester monomer can be produced by reacting at a molar ratio of and dehydrochlorinating.

Dihydroxy aromatic compound Specific examples of the dihydroxy aromatic compound represented by the general formula [II] include phenylhydroquinone, methylhydroquinone, ethylhydroquinone, n-propylhydroquinone, i-propylhydroquinone, n-butylhydroquinone, i. -Butyl hydroquinone, t-butyl hydroquinone, chlorohydroquinone, iodohydroquinone, 4,4'-biphenol, diesters thereof, and the like.

Aromatic Dicarboxylic Acid Compound The aromatic dicarboxylic acid compound represented by the general formula [III] is an aromatic dicarboxylic acid or an aromatic dicarboxylic acid diester. Specific examples of the aromatic dicarboxylic acid include:
Terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,8-
Naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4 "-terphenylenedicarboxylic acid, 2,
Examples thereof include 6-anthracene dicarboxylic acid, 1,5-anthracene dicarboxylic acid, and 9,10-anthracene dicarboxylic acid.

Hydroxyaromatic Carboxylic Acid Compound The hydroxyaromatic carboxylic acid compound represented by the general formula [IV] is the same as the hydroxyaromatic carboxylic acid as the raw material of the ester monomer represented by the general formula [I]. Group carboxylic acids or esters thereof, or acyloxy aromatic carboxylic acids or esters thereof.

Production of Liquid Crystalline Polyester The present invention relates to an ester monomer represented by the general formula [I], a dihydroxy aromatic compound represented by the general formula [II], and an aromatic dicarboxylic acid represented by the general formula [III]. A method for producing a thermotropic liquid crystalline polyester, which comprises subjecting a compound and a hydroxyaromatic carboxylic acid compound represented by the general formula [IV] to polycondensation.

The amount of the dihydroxy aromatic compound represented by the general formula [II] used is 0.05 to 15 equivalents, preferably 0.1 to 9 equivalents, relative to the ester monomer represented by the general formula [I]. is there. The amount of the aromatic dicarboxylic acid compound represented by the general formula [III] used is substantially equivalent to the total amount of the ester monomer [I] and the dihydroxy aromatic compound [II]. That is, the molar ratio is ([I] + [II]) / [III] = 0.9 to 1.1,
The range is preferably 0.95 to 1.05. The amount of the hydroxyaromatic carboxylic acid compound represented by the general formula [IV] is 0.1 to the ester monomer [I].
It is in the range of -17 mol times.

The polymerization reaction is carried out by charging the above-mentioned raw materials (ester monomer [I], dihydroxy aromatic compound [II], aromatic dicarboxylic acid compound [III] and hydroxyaromatic carboxylic acid compound [IV]) at the reaction temperature. To 200
-350 degreeC, Preferably it carries out by making it 250-325 degreeC. The reaction may be carried out by charging all the raw materials at the same time, or the raw material mixture may be sequentially added to the reaction system. The reaction time varies depending on the reaction temperature, but when the reaction temperature is gradually raised from 250 to 325 ° C., it takes about 7 hours. 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 polymerization reaction progresses, the following general formula [V
I], [VII], [VIII], [IX], [X],
The compound represented by [XI] is by-produced. X ¹ -O-Y ¹ (VI) X ¹ -O-Y ² (VII) X ² -O-Y ¹ (VIII) X ² -O-Y ² (IX) X ³ -O-Y ¹ [X] X ³ —O—Y ² [XI] The polycondensation reaction is terminated by distilling these compounds out of the stoichiometric system, but also in terms of reaction time and the like, the reaction is finally performed under reduced pressure. Is preferred. In particular,
At the end of the reaction, the reaction is performed at a vacuum degree of 1 mmHg or less for about 1 hour, and more preferably, the reaction is performed at a vacuum degree of 0.1 mmHg or less for about 0.5 hour.

The liquid crystalline polymer produced according to the present invention contains p-hydroxybenzoic acid units (Ar ¹ + A) based on the total number of moles of aromatic groups (corresponding to Ar ¹ + Ar ² + Ar ³ + Ar ⁴ ).
(corresponding to r ⁴ ) has a molar ratio of 2 to 94%, preferably 60 to 8
It accounts for 5%. The liquid crystalline polymer produced according to the present invention should have a sufficiently large molecular weight. This liquid crystalline polymer has a logarithmic viscosity of 0.6 or more, preferably 1.0 or more, measured using pentafluorophenol as a solvent. The flow starting temperature is 180 ° C or higher.

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. It is possible. Further, a polymer alloy can also be obtained by mixing with another thermoplastic resin. Incidentally, at the time of molding, the liquid crystalline polyester of the present invention, a glass fiber, a reinforcing agent such as carbon fiber,
Additives such as fillers, antioxidants, stabilizers, plasticizers and mold release agents can be added to impart desired properties to the molded article.

[0023]

According to the manufacturing method of the present invention, p-ABA
It is possible to provide a liquid crystalline polyester which can contain a large amount of the structural unit described above, has high uniformity, is excellent in fluidity, and is excellent in heat resistance.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The logarithmic viscosity, the thermogravimetric reduction start temperature (TGA), the flow start temperature and the liquid crystallinity of the liquid crystalline polyester were determined as follows. (1) Logarithmic viscosity It was measured in a pentafluorophenol solvent at 50 ° C. using an Ubbelohde viscometer. However, those that did not dissolve under these conditions are shown by horizontal lines in the table.

(2) Thermogravimetric reduction start temperature (TGA) Using a TG / DTA20 manufactured by SEIDO I & E, measurement was performed in nitrogen at a heating rate of 10 ° C./min. (3) Melting temperature (Tm) and liquid crystallinity Polarizing microscope with hot stage (MP-500D, YA
Using NAKO), it was visually confirmed at 20 to 430 ° C.

Example 1 A 300 ml separable flask equipped with a stirring blade, a thermometer, a distilling tube, and a nitrogen introducing tube was charged with ethylene glycol: hydroxybenzoic acid = 1: 2.
(Molar ratio) 19.32 g (0.05
mol), diacetyl form of phenylhydroquinone 1
3.51 g (0.05 mol), terephthalic acid 16.6
g (0.1 mol) and p-acetoxybenzoic acid 72.
06 g (0.4 mol) was charged. After purging the system with nitrogen three times, the mantle heater was heated to 250 ° C. and heated for 30 minutes to melt the contents. Start stirring, 250
The temperature of the mantle heater was raised stepwise at 2 ° C., 275 ° C. and 300 ° C. for 2 hours each, and the reaction was further carried out at 325 ° C. for 1 hour. At this time, the theoretical amount of acetic acid (34.35 ml)
About 80% (27.5 ml) was distilled. Furthermore, 325
The pressure was reduced to 1 mmHg or less at 0 ° C. and the pressure was reduced for 30 minutes to distill the theoretical amount of acetic acid. After completion of the polycondensation, the contents were taken out from the separable flask while it was hot. Melting anisotropy of this polymer was confirmed by a polarization microscope with a hot stage. Table 1 shows the physical properties of this liquid crystalline polyester.

<Examples 2 and 3 and Comparative Examples 1 and 2> In Example 1, the amounts of the ester monomer and phenylhydroquinone were changed as shown in Table 1 without changing the total mole number. Polycondensation was performed in the same manner as in Example 1 except for the above. The results are shown in Table 1.

[0028]

[Table 1]

<Examples 4 to 7 and Comparative Example 3> Polycondensation was performed in the same manner as in Example 1 except that the amount of p-acetoxybenzoic acid was changed as shown in Table 2. The results are shown in Table 2.

[0030]

[Table 2]

<Examples 8 to 11> Polycondensation was performed in the same manner as in Example 1 except that the dihydroxy aromatic compound shown in Table 3 was used instead of phenylhydroquinone. The results are shown in Table 3.

[0032]

[Table 3]

<Examples 13 and 14> In Example 1,
Polycondensation was performed in the same manner as in Example 1 except that the diol shown in Table 4 was used instead of ethylene glycol as the raw material of the ester monomer. The results are shown in Table 4.

[0034]

[Table 4]

<Examples 15 and 16> In Example 1,
Polycondensation was performed in the same manner as in Example 1 except that the aromatic dicarboxylic acid compounds shown in Table 5 were used instead of terephthalic acid. The results are shown in Table 5.

[0036]

[Table 5]

Comparative Example 4 A reactor similar to that of Example 1 was charged with 63.99 g (0.3%) of polyethylene terephthalate.
33 mol) and p-acetoxybenzoic acid 120.11 g
(0.667 mol) 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. Then, stirring was started, and when a metal bath was heated at 250 ° C. for 2 hours and then at 275 ° C. for about 1 hour, a white solid was precipitated. I tried to measure the intrinsic viscosity of this white solid, but it did not dissolve in a mixed solvent of phenol / 1,1,2,2-terolachloroethane = 1/1 (weight ratio), p-chlorophenol, and pentafluorophenol. The intrinsic viscosity could not be measured. Further, at the flow starting temperature, an insoluble substance was observed and a uniform liquid crystal phase could not be obtained.

<Comparative Example 5> 73.41 g (0.3%) of polybutylene terephthalate was placed in the same reactor as in Example 1.
33 mol) and p-acetoxybenzoic acid 120.11 g
(0.667 mol) 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. Then, stirring was started, and when a metal bath was heated at 250 ° C. for 2 hours and then at 275 ° C. for about 1 hour, a white solid was precipitated. I tried to measure the intrinsic viscosity of this white solid, but it did not dissolve in a mixed solvent of phenol / 1,1,2,2-terolachloroethane = 1/1 (weight ratio), p-chlorophenol, and pentafluorophenol. The intrinsic viscosity could not be measured. Further, at the flow starting temperature, an insoluble substance was observed and a uniform liquid crystal phase could not be obtained.

Claims (1)

[Claims] 1. An ester monoamine represented by the following general formula [I]:
And a dihydroxy aromatic compound represented by the following general formula [II]
Aromatic compounds and aromatic compounds represented by the following general formula [III]
A dicarboxylic acid compound and a compound represented by the following general formula [IV]
Polycondensation with hydroxy aromatic carboxylic acid compounds
Of thermotropic liquid crystalline polyester characterized by
Production method. [Chemical 1](In the formula, R¹Is an aliphatic hydrocarbon group having 1 to 15 carbon atoms
R, Ar¹, Ar², Ar³And Ar^FourAre each independently carbon
An aromatic hydrocarbon group of the number 6-18, X¹, X ²as well as
X³ Are each independently a hydrogen atom or R²-CO- (However
And R²Is a hydrocarbon group having 1 to 6 carbon atoms)
Is a group, Y¹And Y²Are each independently a hydrogen atom.
Or a hydrocarbon group having 1 to 10 carbon atoms)