JP3077856B2 - Aromatic copolyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel thermotropic liquid crystal copolyester which can be melt-processed at a relatively low temperature.

[0002]

2. Description of the Related Art In recent years, various engineering plastics have been developed. In particular, liquid crystal copolymers having optical anisotropy have attracted attention. Adva
nces in Polymer Science 6
0/61 , 61 (1984) describe a homopolymer of P-hydroxybenzoic acid, a copolymer of terephthalic acid and hydroquinone, or a copolymer of naphthalene-2,6-dicarboxylic acid and hydroquinone. Have a melting point of 610 ° C.
Due to the high temperature of 596 ° C. and 577 ° C., it was practically impossible to carry out melt processing without decomposition of the polymer. Also, Japanese Patent Publication No. 47-47870 proposes a copolymer of P-hydroxybenzoic acid, terephthalic acid and hydroquinone, which has a high melting point of 500 ° C. or more and is melt-processed. Is extremely difficult.

As a method for lowering the melting point of the above-mentioned homopolymer of P-hydroxybenzoic acid or a copolymer of terephthalic acid and hydroquinone, there is known a method of copolymerizing with a comonomer having a polymethylene spacer (Pure & Appl. Chem. Vo1.57,
pp. 1537 (1985)). However, in a copolymer using a comonomer having a polymethylene spacer, there is a problem that the moldability and the heat resistance are opposite to each other, so that the melting point is lowered and the heat resistance is also lowered. Also,
As the polymethylene spacer content increases, liquid crystallinity is also lost.

[0004]

An object of the present invention is to provide a novel copolyester having sufficiently practical mechanical properties while having good melt moldability and heat resistance.

[0005]

The present invention comprises a repeating unit A, B, C, D and E of the following formula:

Embedded image (However, n in the formula represents an integer of 1 to 10, and Ar is

Embedded image Wherein the molar ratio of A / [A + B + C + D] is 0 to 85/100;
The present invention relates to an aromatic copolyester in which the molar ratio of [B + C] / [B + C + D] is not less than 5/100 and less than 1, and [B + C + D] and E are substantially equimolar.

The repeating unit A forming the aromatic copolyester of the present invention is derived from p-hydroxybenzoic acid, its acid ester, acid halide, p-acetoxybenzoic acid and the like.

The repeating unit B is derived from 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid, its dicarboxylic acid ester, dicarboxylic acid halide and the like.

The repeating unit C is derived from 3,4'-dimethylbiphenyl-4,3'-dicarboxylic acid, its dicarboxylic acid ester, dicarboxylic acid halide and the like. The above 3,3′-dimethylbiphenyl-4,
4'-dicarboxylic acid and 3,4'-dimethylbiphenyl-4,3'-dicarboxylic acid can be synthesized, for example, by an oxidative coupling reaction of alkyl orthotoluate (Japanese Patent Application No. 63-267202 and Japanese Patent Application No. 63-267202). No. Hei 1-211334).

The repeating unit D is derived from 4,4 '-(alkylenedioxy) -bis-benzoic acid, its dicarboxylic acid ester, dicarboxylic acid halide and the like. Specific examples of 4,4 ′-(alkylenedioxy) -bis-benzoic acid include, for example, 4,4 ′-(ethylenedioxy) -bis-benzoic acid and 4,4 ′-(butylenedioxy) -bis -Benzoic acid and 4,4 '-(hexylenedioxy) -bis-benzoic acid. 4,
As a method for producing 4 ′-(alkylenedioxy) -bis-benzoic acid, for example, 4,4 ′-(hexylenedioxy)
-Bis-benzoic acid can be synthesized by reacting a dipotassium salt of p-hydroxybenzoic acid with 1.6-dichlorohexane (JP-A-2-255639).

The repeating unit E is hydroquinone, 4,4 '
-Dihydroxybiphenyl, 2,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl ether,
And those derived from these diacetyl derivatives. In the present invention, as the repeating unit E, a mixture of a plurality of types described above can be used.

[0011] In the aromatic copolyester of the present invention,
The molar ratio of A / [A + B + C + D] is from 0 to 85/10
0 or less. When this ratio exceeds 85/100, the melting temperature of the aromatic copolyester becomes high, and molding processing is difficult. The molar ratio of [B + C] / [B + C + D] is 5 /
100 or more and less than 1, preferably 8/100 or more
It is less than 1. If this molar ratio is less than 5/100,
Heat resistance tends to decrease. [B + C + D] and E are substantially equimolar.

In addition to the recurring units A, B, C, D and E described above, A, B, C, D and E are recurring by recurring units derived from small amounts of monomers capable of forming other ester bonds.
May be replaced. Specific examples of the repeating unit capable of forming another ester bond include terephthalic acid, isophthalic acid, naphthalene-1.5-dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, and diphenyl ketone.
Dicarboxy units such as those derived from 4,4′-dicarboxylic acid, 2,2′-diphenylpropane-4,4′-dicarboxylic acid, resorcinol, methylhydroquinone, ethylhydroquinone, propylhydroquinone,
Butylhydroquinone, phenylhydroquinone, halogen-substituted hydroquinone, 2,5-di-t-butylhydroquinone, 2,3,5-trimethylhydroquinone, 1.5-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane Dioxy units derived from bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) sulfone, and m-
Oxycarboxy units derived from hydroxybenzoic acid, 4-hydroxy-4'-carboxydiphenyl ether, 1-hydroxy-4-naphthoic acid, 4'-hydroxybiphenyl-4-carboxylic acid and the like can be mentioned.

The substitution ratio of these substituted repeating units is determined so that the melting point of the aromatic copolyester is relatively low.
It is preferably at most 10 mol% with respect to the repeating unit [A + B + C + D + E]. When the substitution ratio exceeds 10 mol%, although the melting temperature of the aromatic copolyester generally increases, depending on the type of the substituted repeating unit, the molding process becomes difficult or the melting temperature is kept relatively low. There are disadvantages such as a decrease in liquid crystallinity and an increase in melt viscosity.

The method for producing the aromatic copolyester of the present invention is not particularly limited, and the aromatic copolyester can be produced by a known ester polycondensation reaction. As a specific example of the manufacturing method,
(1) a method of polycondensing dicarboxylic acid dichloride and diol in the presence of a tertiary amine; (2) a method of polycondensing diphenyl ester of dicarboxylic acid and diol by a phenol removal method; and (3) a method of polycondensing diol with diol. A polycondensation from a diacetyl derivative of the above by a deacetic acid method. A particularly preferred method is a deacetic acid polymerization method.

In the case of the deacetic acid polymerization method, the reaction may be started after all the comonomer components have been added to the reaction vessel, or the comonomer may be added stepwise. In this polycondensation reaction, a method of acetylating and / or pre-condensing the monomer of the component A and the monomer of the component E and then adding the dicarboxylic acid component to perform polycondensation can produce a homogeneous polymer. it can. In this method, the polycondensation is carried out at 230 to 350 ° C., the temperature is raised stepwise to remove acetic acid, and then the reaction is completed under reduced pressure (about 0.1 Torr). The reaction time is preferably 1 to 10 hours.

The polycondensation reaction can be carried out in the presence or absence of a catalyst. Specific examples of the catalyst include metals such as stannous acetate, ferrous acetate, sodium acetate, antimony trioxide, magnesium, iron (III) acetylacetone, titanium tetrabutoxide, sodium hypophosphite, and potassium phosphate. Compounds can be mentioned, but are not limited thereto. The amount of addition is 0.001 to 0.5% based on the weight of the produced polymer. The timing of addition may be at the start of the precondensation or at the start of the polycondensation reaction.

To carry out a polycondensation reaction in the presence of a stabilizer within a range that does not significantly affect the physical properties of the obtained polymer, for the purpose of preventing coloration due to thermal deterioration during polymerization and improving the thermal stability of the resulting polymer. Can be. Specific examples of the stabilizer include phosphorus compounds such as phosphoric acid, phosphorous acid, sodium hypophosphite, triphenyl phosphate, and triphenyl phosphite, and hindered phenols. It is not limited. The amount of addition is 0.001 to 0.5% based on the weight of the produced polymer. The timing of addition may be at the start of the precondensation or at the start of the polycondensation reaction.

The aromatic copolyester of the present invention has a temperature of 60 ° C.
In pentafluorophenol, 0,. It has a logarithmic viscosity (η _inh ) of 1.0 or more at a concentration of 2 g / dl, and exhibits optical anisotropy (liquid crystallinity) in a molten state by observation with a polarizing microscope.

[0019]

The aromatic copolyester of the present invention forms a molten state at a relatively low temperature, for example, at a temperature of 400 ° C. or less, and can be formed into bulk molded articles, films, and fibers by various commonly known molding methods. And so on. Further, since it is dissolved in an organic polar solvent such as pentafluorophenol and p-chlorophenol, it is possible to obtain a molded article by a solution processing method. These moldings are
It can be widely used for electric, electronic and automotive materials. As a remarkable characteristic, because it has liquid crystal properties in the molten state
A highly molecularly oriented molded article can be obtained. Therefore, a polymer material having excellent mechanical strength can be manufactured.

[0020]

Embodiments of the present invention will be described below. (Measurement method) Each physical property value shown in the examples of the present invention was measured by the following method. (1) Optical anisotropy: The sample was placed on a polarizing microscope, and the temperature was raised at a rate of 10 ° C./min under a nitrogen stream using a TH600 RMS type heating device manufactured by Linkham Inc., and visually observed (liquid crystal onset temperature). (2) Thermal decomposition onset temperature; SSC / Seiko Denshi Kogyo
Using a 5200 TGA device, the sample was heated in nitrogen at a rate of 10 ° C./min, and the time-dependent change in weight was observed. (3) Melting point: SSC / 5200D manufactured by Seiko Instruments Inc.
Using an SC device, the sample was heated at 20 ° C./min in nitrogen,
An endothermic peak was observed. (4) Logarithmic viscosity: A sample was dissolved in pentafluorophenol at a concentration of 0.2 g / dl at 60 ° C. and measured using an Ubbelohde viscometer. η _inh was calculated according to the following equation. η _inh = ln (t / t ₀ ) / c where t ₀ is the falling time of pentafluorophenol, t is the falling time of the sample solution, and c is the concentration of the sample.

Example 1 A stirrer, a nitrogen inlet tube and Claisen were attached to a stainless steel container (100 ml) using the upper part of a glass separable three-necked flask. In this container, 4,4'-
7.44 g of diacetoxybiphenyl (BP-Ac) (2
7.54 mmol), p-acetoxybenzoic acid (PHB
(A-Ac) 17.30 g (96.0 mmol) and 30 mg of triphenyl phosphate were charged. After degassing in vacuum and repeating nitrogen replacement three times, the solution was placed in a metal bath in which tin was melted.
After heating at 10 ° C. for 10 minutes, the mixture was allowed to cool, reduced in pressure, and then returned to normal pressure with nitrogen.

To this precondensed mixture was added 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid (PA) 3.0.
4 g (11.25 mmol), 2.43 g of 3,4'-dimethylbiphenyl-4,3'-dicarboxylic acid (QA)
(9.00 mmol), 2.04 g of 4,4 '-(ethylenedioxy) -bis-benzoic acid (PEDA) (6.7 g).
5 mmol) was added. After degassing under vacuum and repeating nitrogen replacement three times, the resultant was heated in a tin bath at 240 ° C. for 1 hour. 1
The temperature was raised to 300 ° C. over a period of time and maintained at 300 ° C. for 1 hour, and the generated acetic acid was distilled off together with flowing nitrogen. 30
While maintaining the temperature at 0 ° C., the degree of vacuum was gradually increased. The reaction was continued for another hour after the degree of reduced pressure reached 0.3 Torr or less.

After completion of the reaction, the pressure was returned to normal temperature and normal pressure while introducing nitrogen. The obtained polymer was pulverized and taken out of the container. Table 1 shows the yield of the obtained polymer, the temperature at which the polymer exhibits optical anisotropy (liquid crystal onset temperature), the melting point, the thermal decomposition onset temperature, the logarithmic viscosity, and the results of elemental analysis.

Example 2 5.75 diacetoxyhydroquinone (HQu-Ac)
g (29.65 mmol), PHBA-Ac 18.6
5 g (103.5 mmol), PA 3.18 g (11.
The same operation as in Example 1 was performed except that 77 mmol), 2.54 g (9.41 mmol) of QA, 2.13 g (7.06 mmol) of PEDA, and 30 mg of triphenyl phosphate were used. Table 1 shows the yield of the obtained polymer, the temperature at which the polymer exhibits optical anisotropy (liquid crystal onset temperature), the melting point, the thermal decomposition onset temperature, the logarithmic viscosity, and the results of elemental analysis.

Example 3 6.12 g (31.5 mmol) of HQu-Ac, PH
18.02 g (100.0 mmol) of BA-Ac, P
A4.05 g (15.0 mmol), QA3.24 g
(12.0 mmol), 0.91 g (3.0 mmol) of PEDA, 30 mg of triphenyl phosphate and 5 mg of potassium phosphate were used in the same manner as in Example 1. The yield of the obtained polymer, the temperature showing the optical anisotropy (liquid crystal onset temperature), melting point, thermal decomposition onset temperature, logarithmic viscosity,
And the results of elemental analysis are shown in Table 1.

Example 4 2,6-diacetoxynaphthalene (NP-Ac) 7.4
7 g (30.6 mmol), PHBA-Ac 18.3
8 g (102.0 mmol), PA 3.38 g (12.
5 mmol), 2.70 g (10.0 mmol) of QA,
The same operation as in Example 1 was performed except that 2.27 g (7.5 mmol) of PEDA and 50 mg of triphenyl phosphate were used. Table 1 shows the yield of the obtained polymer, the temperature at which the polymer exhibits optical anisotropy (liquid crystal onset temperature), the melting point, the thermal decomposition onset temperature, the logarithmic viscosity, and the results of elemental analysis.

Example 5 7.94 g (29.38 mmol) of BP-Ac, PHB
18.45 g (102.4 mmol) of A-Ac, PA
3.24 g (12.0 mmol), QA2.59 g
(9.6 mmol), 4,4 '-(butylenedioxy)
The same operation as in Example 1 was performed except that 2.38 g (7.20 mmol) of -bis-benzoic acid (PBDA) and 30 mg of triphenyl phosphate were used. The yield of the obtained polymer, the temperature showing the optical anisotropy (liquid crystal onset temperature), the melting point,
Table 1 shows the thermal decomposition onset temperature, logarithmic viscosity, and the results of elemental analysis.
It was shown to.

Example 6 7.94 g (29.38 mmol) of BP-Ac, PHB
18.45 g (102.4 mmol) of A-Ac, PA
3.24 g (12.0 mmol), QA2.59 g
(9.6 mmol), 2.58 g of 4,4 '-(hexylenedioxy) -bis-benzoic acid (PHDA) (7.2
0 mmol) and 30 mg of triphenyl phosphate were performed in the same manner as in Example 1. Table 1 shows the yield of the obtained polymer, the temperature at which optical anisotropy is exhibited (liquid crystal onset temperature), the melting point, the thermal decomposition onset temperature, the logarithmic viscosity, and the results of elemental analysis.

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/60 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. The repeating units A, B, C, D and E of the following formula
Consisting of: (Where n represents an integer of 1 to 10, and Ar represents Wherein the molar ratio of A / [A + B + C + D] is 0 to 85/100;
An aromatic copolyester wherein the molar ratio of [B + C] / [B + C + D] is 5/100 or more and less than 1, and [B + C + D] and E are substantially equimolar.