JP3077833B2 - Aromatic copolyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel thermotropic liquid crystal copolyester.

[0002]

2. Description of the Related Art In recent years, various engineering plastics have been developed. Among them, liquid crystal copolymers having optical anisotropy have attracted attention. A
dvances in Polymer Science
60/61, p. 61, 1984 describes homopolymers of P-hydroxybenzoic acid, copolymers of terephthalic acid and hydroquinone, and copolymers of naphthalene-2,6-dicarboxylic acid and hydroquinone. The polymers have a melting point of 61
Since the temperature was as high as 0 ° C., 596 ° C., and 577 ° C., it was practically impossible to perform melt processing without decomposing the polymer.
Japanese Patent Publication No. 47-87070 discloses a copolymer of P-hydroxybenzoic acid, terephthalic acid and hydroquinone.
It has the above high melting point and is extremely difficult to melt process.

As a method for lowering the melting point of the above-mentioned homopolymer of P-hydroxybenzoic acid or a copolymer of P-hydroxybenzoic acid, terephthalic acid and hydroquinone, a method of copolymerizing with polyethylene terephthalate is known (Mol. Cryst). .Liq.Cry
st. 1989, Vol. 169, pp. 23-49). However, in this polyethylene terephthalate copolymer system,
It is said that moldability and heat resistance have a front-to-back relationship, and the heat resistance decreases as the melting point decreases. Also, as the polyethylene terephthalate content increases, the liquid crystallinity is lost.

[0004]

The object of the present invention is to provide 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid and / or 3,4'-
This is a new copolyester containing dimethylbiphenyl-4,3'-dicarboxylic acid and polyethylene terephthalate as essential components, and has a sufficiently practical machine with good melt moldability and heat resistance. Provide a copolyester having physical properties.

[0005]

The present invention comprises a repeating unit 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 E / [A + B + C + D + E] The molar ratio is larger than 0 and 70/100 or less, and [B + C] / [B
+ C + D] is greater than 5/100 and less than or equal to 1, and [B + C + D] and F provide substantially equimolar aromatic copolyesters.

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

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

The repeating unit C forming the aromatic copolyester of the present invention is 3,4'-dimethylbiphenyl-
It is derived from 4,3'-dicarboxylic acid, its dicarboxylic acid ester 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 o-toluate (Japanese Patent Application No. 63-267202). And Japanese Patent Application No. 1-211334).

The repeating unit E forming the aromatic copolyester of the present invention is derived from polyethylene terephthalate synthesized by a known method. The above polyethylene terephthalate has a logarithmic viscosity η _inh at 30 ° C in a mixed solvent of phenol and tetrachloroethane (weight ratio of 1: 1) of 0.05 to 1.0 dl / g, preferably 0.1 to 0 dl / g. .7. When polyethylene terephthalate having η _inh out of this range is used, the mechanical strength of the obtained aromatic copolyester decreases.
Further, acetylated polyethylene terephthalate obtained by heating and drying polyethylene terephthalate together with acetic anhydride may be used.

The repeating unit F forming the aromatic copolyester of the present invention is derived from a hydroquinone derivative. Hydroquinone derivatives include hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, alkyl-substituted hydroquinone having 1 to 8 carbon atoms such as butylhydroquinone, aryl-substituted hydroquinone such as phenylhydroquinone, halogen-substituted hydroquinone such as chlorohydroquinone, and these. The diacetyl derivative of is mentioned as a specific example. In the present invention, the repeating unit F may be derived from a mixture of a plurality of types of hydroquinone derivatives described above.

In the aromatic copolyester of the present invention, the molar ratio of A / [A + B + C + D + E] is 85/10
0 or less, preferably 20/100 to 80/100
It is. If the molar ratio exceeds 85/100, the melting temperature of the aromatic copolyester becomes high, and molding processing is difficult. The molar ratio of E / [A + B + C + D + E] is greater than 0 and not more than 70/100, preferably 5/100.
５０50/100. The molar ratio of [B + C] / [B + C + D] is greater than 5/100, preferably 8/100
It is larger and 1 or less. When the molar ratio is less than 5/100, the melting temperature of the aromatic copolyester becomes high similarly to the above, and molding is difficult. Also, [B + C
+ D] and F are substantially equimolar.

In addition to the above formulas A, B, C, D, E and F, formulas A, B, C, D, E and F are substituted by small amounts of other monomers capable of forming ester bonds. Is also good. Specific examples of other monomers capable of forming an ester bond include isophthalic acid, naphthalene-1,5-dicarboxylic acid, diphenylether-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid,
Diphenyl ketone-4,4'-dicarboxylic acid, 2,2 '
Dicarboxylic acid compounds such as -diphenylpropane-4,4'-dicarboxylic acid, resorcinol, 2,5-di-t-butylhydroquinone, 2,3,5-trimethylhydroquinone, 1,5-dihydroxynaphthalene, 2,2- Dihydroxy compounds such as bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ether, m-hydroxybenzoic acid, 4-hydroxy- 4'-carboxydiphenyl, 1
Oxycarboxy compounds such as -hydroxy-4-naphthoic acid can be mentioned. Of these monomers,
The substitution ratio with respect to (A + B + C + D + E + F) is preferably 10 mol% or less in order to relatively lower the melting temperature of the aromatic copolyester.

The aromatic copolyester of the present invention is synthesized by a polycondensation reaction. In particular, a method of deacetic acid polymerization from an acetyl derivative of a carboxylic acid component and a hydroxy component is generally used. The polycondensation reaction can be performed in the presence or absence of a catalyst. Specific examples of the catalyst include metals and metal compounds such as stannous acetate, ferrous acetate, sodium acetate, antimony trioxide, magnesium, iron (III) acetylacetone or titanium tetrabutoxide, but are not limited thereto. It is not something to be done.

For the purpose of preventing coloring due to thermal deterioration during polymerization and improving the thermal stability of the produced polymer, a polycondensation reaction is carried out in the presence of a stabilizer within a range that does not greatly affect the physical properties of the obtained polymer. It can be carried out. As specific examples of the stabilizer,
Phosphorus compounds such as phosphoric acid, phosphorous acid, sodium hypophosphite, triphenyl phosphate, triphenyl phosphite,
Alternatively, hindered phenols can be mentioned, but not limited thereto. In the case of the deacetic acid polymerization method, the reaction temperature is 230 to 350 ° C., and the temperature is raised stepwise to distill off acetic acid, and then reduced pressure (、 0.1 mmHg).
To complete the reaction. The reaction time is preferably 1 to 10 hours.

[0016]

The copolyester of the present invention forms a molten state at a relatively low temperature, for example, at a temperature of 400 ° C. or less,
Bulk molded articles, films, fibers and the like can be formed by various commonly known molding methods. 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,
Can be widely used for electronic and 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.

[0017]

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 onset temperature: Place the sample on a polarizing microscope,
Using a TH600RMS type heating apparatus manufactured by Linkham Inc., the temperature was raised at a rate of 10 ° C./min under a nitrogen stream and observed visually. (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 / 5200 manufactured by Seiko Denshi Kogyo KK
The sample was heated in nitrogen at a rate of 20 ° C./min using a DSC apparatus, and 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 = 1n (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.

Reference Example 1 A 100 mL glass separable three-necked flask was equipped with a stirrer, a nitrogen inlet tube, and a condenser tube. In this container, 29.13 g of dimethyl terephthalate (150 m
M), ethylene glycol 20 mL (360 mM), calcium acetate dihydrate 0.027 g (0.15 mM),
0.009 g (0.03 mM) of antimony oxide was charged, and the temperature was raised from 180 ° C. to 200 ° C. for 3 hours under a nitrogen stream. During this time, almost the theoretical amount of methanol was distilled off.
Thereafter, a vacuum pump was connected to the reaction system, and 1 m
The pressure was reduced to mHg. Further, the temperature was raised to 220 ° C.
When the reaction was continued for a minute, a part of the reaction solution began to solidify. Nitrogen was introduced to normal pressure, and the mixture was allowed to cool. The crude reaction product was dissolved in a mixture of phenol and tetrachloroethane (weight ratio 1: 1), and precipitated by pouring into 1 L of methanol.
The precipitate was collected by filtration, washed well with methanol, and dried. The yield was 25.68 g, 89%. The logarithmic viscosity of this polyethylene terephthalate is 30 in a mixed solvent of phenol and tetrachloroethane (weight ratio 1: 1).
0.1 ° C. at a concentration of 1.0 dl / g. Acetic anhydride 4 was added to 16.05 g of the above polyethylene terephthalate.
0 mL was added and heated at 140 ° C. for 2 hours. After distilling off excess acetic anhydride, it was dried at 60 ° C. overnight to obtain acetylated polyethylene terephthalate (hereinafter referred to as PETAc). The weight gain was 5.4%.

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,
-Dimethylbiphenyl-4,4'-dicarboxylic acid 5.4
1 g (20.0 mM), terephthalic acid 3.32 g (2
0.0 mM), 7.87 g of hydroquinone diacetate
(40.5 mM), 4.05 g (20.0
mM), 10.81 g of p-acetoxybenzoic acid (60.
0 mM) and 0.031 g of triphenyl phosphate (0.
1 mM), vacuum degassing and nitrogen replacement were repeated three times, and the temperature was raised stepwise from 240 ° C. to 310 ° C. over 3 hours and 50 minutes in a tin-dissolved metal bath. Distilled. The pressure inside the system was gradually reduced to 0.1 mmHg at 310 ° C. for 30 minutes, followed by stirring for 1 hour. Nitrogen was introduced to normal pressure, the solution was allowed to cool and returned to room temperature. The polymer is crushed and removed from the container, washed with acetone, dried,
22.03 g of copolyester was obtained (96% yield). Table 1 shows the measurement results of the optical anisotropy onset temperature, melting point, thermal decomposition onset temperature, and logarithmic viscosity of the obtained copolyester.

Example 2 In Example 1, 3,3'-dimethylbiphenyl-
2.97 g (11.0 mM) of 4,4′-dicarboxylic acid,
2.43 g (9.0 mM) of 3,4′-dimethylbiphenyl-4,3′-dicarboxylic acid, 3.32 g of terephthalic acid
(20.0 mM), hydroquinone diacetate 7.8
7 g (40.5 mM), 4.05 g PETAc (2
0.0 mM), 10.81 g of p-acetoxybenzoic acid
(60.0 mM) and triphenyl phosphate 0.031
In the same manner as in Example 1 except that polycondensation was performed using g (0.1 mM), 22.10 g of a copolyester was obtained (96% yield). Table 1 shows the measurement results of the optical anisotropy onset temperature, melting point, thermal decomposition onset temperature, and logarithmic viscosity of the obtained copolyester.

Example 3 A reaction vessel similar to that of Example 1 was charged with 9.19 g (34 m) of 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid.
M), 5.65 g (34 mM) of terephthalic acid, 13.40 g (69 mM) of hydroquinone diacetate, PET
Ac 3.44 g (20.0 mM) and 0.003 g of iron acetylacetone were charged, and vacuum degassing and nitrogen purging were performed for 3 hours.
After repetition, the temperature was raised stepwise from 240 ° C. to 310 ° C. in a metal bath in which tin was dissolved over 5 hours. 310 ° C
After stirring for 1 hour, the pressure was gradually reduced to 0.1 mmHg, and the mixture was further stirred for 1 hour. The same treatment as in Example 1 was performed to obtain 21.70 g of a copolyester (yield: 94).
%). Optical anisotropy onset temperature of the obtained copolyester,
Table 1 shows the measurement results of the melting point, the thermal decomposition onset temperature, and the logarithmic viscosity.

[Table 1]

Claims (1)

(57) [Claims] 1. It is composed of repeating units A, B, C, D, E and F of the following formula: (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 E / [A + B + C + D + E] The molar ratio is larger than 0 and 70/100 or less, and [B + C] / [B
+ C + D] is an aromatic copolyester having a molar ratio of more than 5/100 and not more than 1 and wherein [B + C + D] and F are substantially equimolar.