JP3267021B2 - 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. Advances
In Polymer Science 60/61 , 61 (1984), P-hydroxybenzoic acid homopolymer, copolymer of terephthalic acid and hydroquinone, or copolymer of naphthalene-2,6-dicarboxylic acid and hydroquinone are described. However, each of these polymers has a melting point of 610
, 596 ° C, and 577 ° C, it was virtually impossible to melt-process without decomposing the polymer. Also,
Japanese Patent Publication No. 47-47870 discloses a copolymer of P-hydroxybenzoic acid, terephthalic acid and hydroquinone, but this polymer has a high melting point of 500 ° C. or more and is extremely difficult to melt-process. is there.

Hitherto, various proposals have been made for a method of improving the melt processability by lowering the melting point of liquid crystal polyester. (Brit. Polymer Journal 132 (1980)). Polyester containing 2,2'-dimethylbiphenyl-4,4'-dicarboxylic acid as a monomer component (Makromol. Chem., 189, 2029 (198
8), Makromol.Chem.Makromol.Symp., 26 , 47 (1989),
JP-A-64-66231), polyesters containing 2,2'-bis (trifluoromethyl) -biphenyl-4,4'-dicarboxylic acid as a monomer component (Journal of Polymer Sci., Part
C, Polymer Letters, 25 , 11 (1987), Makromolecule
s, 20 , 2374 (1987)). However, 2,2'-substituted-biphenyl-4,4'-dicarboxylic acids are
The coplanarity of the phenyl ring is hindered, thus reducing the crystallinity of the polymer. In general, it has been pointed out that a polymer having low crystallinity does not have a satisfactory mechanical strength.

[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]

Technical Solution to the Problems The present invention substantially comprises repeating units A, B, C, D, E and F of the following formula:

[0006]

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[0007]

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(In the formula, R represents a hydrogen atom, an alkyl group or an aryl group having 1 to 8 carbon atoms, or a halogen atom.) The molar ratio of A / [A + B + C + D + E] is 85/100 or less, and [B + C + D] / [B + C + D + E] molar ratio is 5
Greater than / 100 and less than or equal to 1; [B + C + D + E] and F
Provides an aromatic copolyester which is substantially equimolar and in which the repeating unit D is essential.

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

The repeating unit B forming the aromatic copolyester of the present invention is derived from 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid, its dicarboxylic acid ester or dicarboxylic acid halide. Things.

The repeating unit C forming the aromatic copolyester of the present invention is derived from 3,4'-dimethylbiphenyl-4,3'-dicarboxylic acid, its dicarboxylic acid ester or dicarboxylic acid halide. Things.

The repeating unit D forming the aromatic copolyester of the present invention is derived from 4,4'-dimethylbiphenyl-3,3'-dicarboxylic acid, its dicarboxylic acid ester or dicarboxylic acid halide. Things. The above 3,3′-dimethylbiphenyl-4,4′-dicarboxylic acid,
4'-dimethylbiphenyl-4,3'-dicarboxylic acid and 4,4 '
-Dimethylbiphenyl-3,3'-dicarboxylic acid is, for example, o-
It can be synthesized by an oxidative coupling reaction of an alkyl toluate (see JP-A-2-115143 and JP-A-3-77843).

The repeating unit E forming the aromatic copolyester of the present invention is derived from terephthalic acid, its dicarboxylic acid ester or dicarboxylic acid halide.

The repeating unit F forming the aromatic copolyester of the present invention comprises a hydroquinone derivative, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, 2,6-dihydroxynaphthalene, 2,7 -Dihydroxynaphthalene and derivatives thereof.

Examples of the hydroquinone derivative include hydroquinone, and halogen atoms such as an alkyl group-substituted hydroquinone having 1 to 8 carbon atoms, such as methylhydroquinone, ethylhydroquinone, propylhydroquinone, and butylhydroquinone; Specific examples include substituted hydroquinones and their diacetyl derivatives. In the present invention, the repeating unit F may be derived from a mixture of a plurality of the above-mentioned dihydroxy derivatives.

In the aromatic copolyester of the present invention, the molar ratio of A / [A + B + C + D + E] is not more than 85/100, preferably 0/100 to 75/100. When the molar ratio exceeds 85/100, the melting temperature of the aromatic copolyester becomes high, and molding processing becomes difficult.

The molar ratio of [B + C + D] / [B + C + D + E] is more than 5/100 and 1 or less, preferably 8/1.
Greater than 00 and less than or equal to 1. When the molar ratio is less than 5/100, the melting temperature of the aromatic copolyester becomes high similarly to the above, and molding processing becomes difficult.

The molar ratio of [D] / [B + C + D] is not particularly limited, but is preferably 1 / 1000-1 and particularly preferably 1 / 100-1. Also, [B + C + D + E]
And F are substantially equimolar.

In addition to the above-mentioned repeating units A, B, C, D, E and F, even if the repeating units A, B, C, D, E and F are substituted by a small amount capable of forming another ester bond, Good.

Specific examples of other repeating units capable of forming an ester bond include isophthalic acid, naphthalene-1,5-dicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenylketone-4,4'-dicarboxylic acid , Dicarboxy units such as those derived from diphenylpropane-4,4'-dicarboxylic acid, resorcinol, 2,5-di-t-butylhydroquinone, 2,3,5-trimethylhydroquinone, 1,5-dihydroxynaphthalene , 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) ketone, bis (4
-Hydroxyphenyl) dihydroxy units derived from sulfone, etc., m-hydroxybenzoic acid, 4-hydroxy
-4'-carboxydiphenyl ether, 1-hydroxy-4-
Oxycarboxy units derived from naphthoic acid, 4'-hydroxybiphenyl-4-carboxylic acid and the like can be mentioned. The substitution ratio of these substituted repeating units is to lower the melting temperature of the aromatic copolyester,
It is preferably 20 mol% or less based on [A + B + C + D + E + F].

The method for producing the aromatic copolyester of the present invention is not particularly limited, and it 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 dephenolation method; (3) a method of dicarboxylic acid and diol And polycondensation from a diacetyl derivative of the above by a deacetic acid method. In particular, a method of deacetic acid polymerization from an acetyl derivative of a carboxylic acid component and a hydroxy component is generally used.

In this polycondensation, a homopolymer is produced by using a method of acetylating and / or precondensing the monomer of the component A and the monomer of the component F, and then adding the dicarboxylic acid component to perform the polycondensation. be able to. The polycondensation reaction can be performed in the presence or absence of a catalyst. Specific examples of the catalyst include metals and 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 polycondensation reaction is carried out 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. be able to. As specific examples of the stabilizer,
Phosphorus compounds such as phosphoric acid, phosphorous acid, sodium hypophosphite, triphenyl phosphate, triphenyl phosphite,
Alternatively, hindered phenol can be mentioned. In the case of the deacetic acid polymerization method, the reaction is carried out at a temperature of 230 to 350 ° C., and the temperature is raised stepwise to distill off acetic acid.
1 mmHg) to complete the reaction. The reaction time is preferably 1 to 10 hours.

[0024]

The copolyester of the present invention forms a molten state at a relatively low temperature, for example, at a temperature of 400 ° C. or lower, and is formed into a bulk molded product by various commonly known molding methods.
It can be a film, fiber or the like. 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 molded products are electric, electronic,
Can be widely used for automotive materials. As a remarkable property, since it has liquid crystallinity in a molten state, a molded article having a high degree of molecular orientation can be obtained, and thus a polymer material having excellent mechanical strength can be produced.

[0025]

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 start temperature: Place the sample on a polarizing microscope, and use a TH600RMS type heating device manufactured by Linkham Inc. under a nitrogen stream.
The temperature was raised at a rate of 10 ° C./min and observed visually. (2) Thermal decomposition onset temperature; SSC / 5200 T manufactured by Seiko Denshi Kogyo
Using a GA 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: Using an SSC / 5200 DSC apparatus manufactured by Seiko Instruments Inc., the sample was heated in nitrogen at 20 ° C./min, and an endothermic peak was observed. (4) Logarithmic viscosity; in pentafluorophenol at 60 ° C,
The sample was dissolved at a concentration of 0.2 g / dl 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 stainless steel container (100 mL) was equipped with a stirrer, a nitrogen inlet tube, and Claisen using the upper part of a glass separable three-necked flask. In this container, 6.918 g (38.4 mM) of p-acetoxybenzoic acid (PHBA-Ac), 11.409 g (57.6 mM) of diacetoxyhydroquinone (HQu-Ac), and 32 mg of triphenyl phosphate were charged, degassed under vacuum, and nitrogen degassed. After the substitution was repeated three times, the mixture was heated at 250 ° C. and normal pressure for 20 minutes under a nitrogen flow. Once cooled to 100 ° C., 5.189 g (19.2 mM) of 3,3′-dimethylbiphenyl-4,4′-dicarboxylic acid (PA), 3,4′-dimethylbiphenyl-4,3′-dicarboxylic acid (QA ) 2.076g (7.68
mM), 4,4'-dimethylbiphenyl-3,3'-dicarboxylic acid (R
A) 2.076 g (7.68 mM), terephthalic acid (TPA) 3.828 g (23.04
mM). After degassing in vacuum and repeating nitrogen replacement three times, under nitrogen flow 250 ° C, 1 hour, 260 ° C 30 minutes, 270 ° C
Acetic acid was distilled off by heating for 30 minutes, 280 ° C. for 30 minutes, 300 ° C. for 1 hour, and then reducing the pressure and heating at 0.1 torr at 300 ° C. for 25 minutes. Atmospheric pressure was introduced by introducing nitrogen, and the temperature was returned to room temperature. The yield of the polymer was 21.12 g (96%), and the elemental analysis was as follows: C 73.67, H 4.15 (calculated values C 73.64, H 4.07). η _inh is 1.58dl /
g, the temperature showing optical anisotropy was 274 ° C, the melting point was 261 ° C, the crystallization temperature was 212 ° C, and the thermal decomposition temperature was 442 ° C.

Example 2 17.295 g (96 mM) of PHBA-Ac, 8.822 g (32.6 mM) of 4,4'-diacetoxybiphenyl (BP-Ac), triphenyl phosphate
Using 9.6 mg, the mixture was heated at 250 ° C. for 20 minutes in the same manner as in Example 1. After that, PA 1.297g (4.8mM), QA 0.865g (3.2mM), RA
0.865 g (3.2 mM) and 3.456 g (20.8 mM) of TPA were added. After degassing in vacuum and repeating nitrogen replacement three times, under nitrogen flow at 250 ° C,
The temperature was raised to 310 ° C. over 1 hour and 0.5 hours, and the pressure was reduced at 310 ° C. for 1 hour, and the reaction was performed at 310 ° C. for 1 hour at 0.05 torr. Polymer yield was 22.17 g (97%), elemental analysis was C 73.82,
H 3.79 (calculated C 73.78, H 3.79). η
_inh is 3.68dl / g, temperature showing optical anisotropy is 320 ℃, melting point is 305 ℃, crystallization temperature is 260 ℃, pyrolysis temperature is 450 ℃
Met.

Claims (1)

(57) [Claims] 1. It consists essentially of the repeating units A, B, C, D, E and F of the following formula: Embedded image (In the formula, R represents a hydrogen atom, an alkyl group or an aryl group having 1 to 8 carbon atoms, or a halogen atom.) The molar ratio of A / [A + B + C + D + E] is 85/100 or less, and [B + C + D] / [B + C + D + E Is 5
Greater than / 100 and less than or equal to 1; [B + C + D + E] and F
Is an aromatic copolyester which is substantially equimolar and in which the repeating unit D is essential.