JPH0625249B2 - Aromatic polyester - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to aromatic polyesters. More specifically, it relates to an aromatic polyester having a high degree of heat resistance and moldability as a resin for paints, molded products or fibers.

[0002]

2. Description of the Related Art Dibasic acids such as terephthalic acid, isophthalic acid or carbonic acid, bisphenol A (2,2'-propylidene-4,4'-biphenol), bisphenol S
A polycondensate with an aromatic dihydroxy compound such as (4,4′-dihydroxydiphenyl sulfone) or 4,4′-dihydroxybiphenyl is referred to as polyarylate or wholly aromatic polyester and has already been put into practical use.
On the other hand, although aromatic hydroxycarboxylic acid, especially aromatic polyester, which is a single polycondensation product of parahydroxybenzoic acid, has already been known to have extremely high heat resistance and mechanical strength, practical molding Due to its difficulty, it was never widely used. But recently
When para-hydroxybenzoic acid is copolymerized with a component that lowers the melting point of the polycondensate in an appropriate ratio, it exhibits anisotropy (thermotropic liquid crystallinity) at the time of melting, which not only facilitates molding processing. It was found that an aromatic polyester having a high elastic modulus and mechanical strength can be obtained because the polymer chains are oriented in the flow direction. The practical application of these melt-anisotropic polyesters has only just begun, and future technological development is expected.

[0003]

The temperature range in which a non-crystalline polymer compound has a high elastic modulus is closely related to its glass transition temperature. Similarly, it is conceptually understood that even in a partially crystalline polymer compound, the temperature range of high elastic modulus is closely related to the glass transition temperature of the amorphous region when the crystal region is not extremely large. ing. From this, it can be said that the temperature range of the high elastic modulus of the non-crystalline or partially crystalline polymer compound, that is, the controlling factor of the heat resistance is generally the glass transition temperature of the non-crystalline portion. In addition, the chemical structural element of the component forming the amorphous portion has a great influence on the heat resistance and is important. In particular, in the case of melt-anisotropic polyester, it is often possible to clearly distinguish the crystalline part and the non-crystalline part, and the glass transition temperature of the non-crystalline part is an important factor for determining the temperature range of high elastic modulus. For example, terephthalic acid and ethylene glycol 30-40
A polycondensate composed of mole percent and 70 to 60 mole percent of p-hydroxybenzoic acid has melt anisotropy and the molded product or fiber has a high elastic modulus, but since the amorphous portion has a low glass transition temperature, the temperature is 60 ° C. Shows only moderate heat resistance. For the purpose of remedying this drawback, heat treatment of the molded product or fiber for a long time, or increasing the proportion of parahydroxybenzoic acid to make the crystal region extremely large is performed, but the former has a low production efficiency. Is said to be a drawback, and the latter is said to have a poor moldability. An object of the present invention is to provide a highly heat-resistant aromatic polyester having excellent moldability by introducing an amorphous part having a high glass transition temperature formed by a tetracyclic aromatic dihydroxy compound. .

[0004]

The aromatic polyester of the present invention is a polycondensate containing an aromatic dihydroxy compound, an aromatic dicarboxylic acid, and an aromatic hydroxycarboxylic acid as the main constituents.

[0005]

[Chemical 2] 50 to 100 mol%, the aromatic dicarboxylic acid component is substantially equimolar to the aromatic dihydroxy compound, and the aromatic hydroxycarboxylic acid exceeds 10 mol% with respect to the aromatic dihydroxy compound and 400 Up to mol% and the average molecular weight of the polycondensate is 5,000
It is characterized by being 0 to 100,000.

The (3,3'-diphenyl-4,4'-dihydroxy) biphenyl represented by the formula (1) has an extremely rigid chemical structure and has an effect of giving a high glass transition temperature as a segment of a polymer compound. have. Also, its chemical structure is bulky, lacks linearity, and hardly forms crystalline segments.

The polycondensate of only the aromatic dihydroxy compound of the formula (1) and the aromatic dicarboxylic acid has a high glass transition temperature and is heat resistant, but almost no crystallinity is observed. Mechanical strength (tensile strength, bending strength, impact resistance, etc.)
In order to maintain the above, a polycondensate having a considerably high melt viscosity is required, and a certain degree of decrease in moldability is unavoidable. However, a strong crystalline component as a constituent of the polycondensate,
More preferably, by adding a strongly crystalline and melt-anisotropic component, heat resistance and mechanical strength are maintained, and moldability is remarkably improved.

Aromatic dihydroxy compounds other than formula (1) that can be used in the present invention include resorcin, hydroquinone, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone (2,5).
-Dihydroxybiphenyl), methoxyhydroquinone, phenoxyhydroquinone, 4,4'-dihydroxybiphenyl, (3,3'-diphenyl-4,4'-dihydroxy) diphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4'- Dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone,
4,4'-dihydroxydiphenylmethane, bisphenol A, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy)
Ethane, 1,4-dihydroxynaphthalene, or 2,6
-Dihydroxynaphthalene and the like. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 5-
Metal salts of sulfoisophthalic acid, 4,4′-dicarboxybiphenyl, 4,4′-dicarboxydiphenyl ether, 4,4′-dicarboxydiphenyl sulfide,
4,4'-dicarboxydiphenyl sulfone, 4,4 '
-Dicarboxybenzophenone, 1,2-bis (4-carboxyphenoxy) ethane, 1,4-dicarboxynaphthalene, 2,6-dicarboxynaphthalene and the like can be mentioned. And as the aromatic hydroxycarboxylic acid, meta-hydroxybenzoic acid, para-hydroxybenzoic acid, 3
-Chloro-4-hydroxybenzoic acid, 3-bromo-4-
Hydroxybenzoic acid, 3-methyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 4-hydroxy-
4'-Carboxybiphenyl or 2-hydroxy-6-
Carboxynaphthalene etc. are mentioned. Among these constituents, the one with particularly strong crystallinity is hydroquinone,
4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, terephthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, 4,4 ' -Dicarboxydiphenyl sulfide, 4,4'-dicarboxybenzophenone, 1,
2-bis (4-carboxyphenoxy) ethane, 2,6
-Dicarboxynaphthalene, para-hydroxybenzoic acid, 4-hydroxy-4'-carboxybiphenyl, etc. are mentioned.

Among the constituents of the polycondensate, the aromatic dihydroxy compound and the aromatic dicarboxylic acid have almost equal molar ratios,
Aromatic hydroxycarboxylic acids form high molecular weight polycondensates in any molar ratio. It is difficult to heat each constituent as it is to cause polycondensation, and it is usually preferable to acetylate the hydroxy group of the constituent before the polycondensation reaction. The polycondensation reaction can be carried out at a temperature of 200 ° C to 350 ° C. The acetic acid produced by the polycondensation reaction is preferably first removed from the reaction system under normal pressure and finally under reduced pressure. When the reaction system is particularly crystalline and heterogeneous, acetic acid is taken out under pressure and finally depressurized to obtain a more uniform system and good results are obtained. The molecular weight of the polycondensate can be adjusted by adjusting the molar ratio of the aromatic dihydroxy compound and the aromatic dicarboxylic acid as constituent components, but this gives good results when the molecular weight is relatively low. . In the range where the molecular weight is high, a method of controlling the size of the molecular weight by carrying out the reaction while taking the melt viscosity of the polycondensate as a guide is adopted. The method for measuring the molecular weight of the polycondensate is gel permeation chromatography for a solvent-soluble polycondensate,
A solution viscosity method, a boiling point raising method or a melting point lowering method is preferable, and a solvent insoluble polycondensate method is preferably a terminal group quantitative method.

As described above, according to the present invention, the aromatic polyester has a molecular weight of 5,000 to 10 depending on the purpose.
10,000 can be manufactured.

[0011]

EXAMPLES Next, specific examples of the present invention will be described.

Example 1 (Synthesis of Monomer) Internal Volume with Stirrer, Thermometer and Reflux Cooler 2,
In a 3,000 ml hard glass three-necked flask, (3,3'-diphenyl-4,4'-dihydroxy) biphenyl (melting point; 139 ° C) 507 g (1.5 mol), acetic anhydride 460 g (4.5 mol). And 800 grams of toluene. Heat the flask while stirring to allow the contents to boil gently. The contents are occasionally sampled to follow the progress of the reaction by high performance liquid chromatography. In about 8 hours (3,3 '
Since -diphenyl-4,4'-dihydroxy) biphenyl and its monoacetate are completely lost, this is the end point of the acetylation reaction. The reaction mixture is filtered while hot to remove impurities and then slowly cooled to 10 ° C. to precipitate crystals. The crystals are filtered and dried to give white crystals 578 having a melting point of 206 ° C. and a saponification value of 264 (theoretical value: 265.6).
Grams are obtained. This is (3,3'-diphenyl-
It is confirmed to be 4,4'-diacetoxy) biphenyl.

Example 1-1 Internal volume 10 equipped with a thermometer, gas blowing port and distillation port
25.4 g (0.06 mol) of (3,3′-diphenyl-4,4′-diacetoxy) biphenyl obtained in Example 1 was placed in a 0 ml hard glass three-necked flask and 10.0 terephthalic acid. Grams (0.06 mol) and paraacetoxybenzoic acid 10.8 g (0.06 mol) are charged. Put the flask in a bath of silicone oil and raise the temperature of the bath while blowing nitrogen gas through the gas inlet. Bath temperature is 250 ℃ to 260 ℃
When the temperature reaches ℃, the polycondensation reaction starts and the acetic acid produced distills out from the distillation port. The temperature of the bath was raised to 310 ° C., and after 30 minutes, the distillation port was connected to a vacuum vessel, the gas blowing port was replaced with a capillary tube, and the pressure was gradually reduced to 1 Torr. After 30 minutes of heating at 1 torr, the inside of the flask becomes a very viscous liquid, so the flask is pulled out of the bath and cooled. The product solidified by cooling is taken out by breaking the flask. It is confirmed that the product is amorphous having a softening point of 173 ° C., is dissolved in tetrahydrofuran, and has an average molecular weight of 5,200 by gel permeation chromatography. In addition, the aromatic polyester as a product was decomposed into its constituents with alcoholic potassium hydroxide and quantified by liquid chromatography. As a result, (3,3'-diphenyl-4,4'-dihydroxy) biphenyl The molar ratio of acid, para-hydroxybenzoic acid and phenol is 1.00, 1.00, 1.01 and 0.004, confirming the desired production of aromatic polyester.
It is considered that the formation of some phenol is due to decarboxylation of parahydroxybenzoic acid during the reaction or during alkali decomposition.

Example 1-2 Spiral type stirrer, thermometer, gas inlet,
(3,3′-diphenyl-4,4′-diacetoxy) biphenyl 105.6 obtained in Example 1 was placed in a stainless steel autoclave with a pressure of 10 atm and a volume of 600 ml, which was equipped with a distillation port and a discharge port at the bottom. Gram (0.25 mole), terephthalic acid 41.5 grams (0.25 mole) and paraacetoxybenzoic acid 135.
Charge 1 gram (0.75 mol). Carbon dioxide gas was blown from the gas blowing port to adjust the valve connected to the end of the distillation port to keep the inside of the autoclave at a gauge pressure of 6 kg / cm ² . In this state, the temperature of the autoclave is raised, and when it reaches 150 ° C, stirring is started and the temperature is raised to 310 ° C. During this period, the reaction starts and acetic acid is produced, so that the distillate is distilled out. After reaching 310 ° C, open the valve little by little so that the pressure in the autoclave gradually drops to atmospheric pressure. Subsequently, the end of the distillation port is connected to a vacuum device and the pressure is gradually reduced to 1 Torr. After 50 minutes after setting to 1 Torr, the valve of the vacuum device was closed, nitrogen gas was blown into the autoclave from the gas injection port, and the gauge pressure was set to 6k again.
g / cm ² . Next, the outlet at the bottom of the autoclave is opened to press out the product. The product has melt anisotropy and is difficult to dissolve in an organic solvent. It is confirmed that the number average molecular weight is 10,200 by the quantitative method of the terminal groups (hydroxy group, carboxy group, acetyl group and phenoxy group). Further, the components were redissolved in the same manner as in Example 1-1, and the molar ratio of (3,3′-diphenyl-4,4′-dihydroxy) biphenyl, terephthalic acid, parahydroxybenzoic acid and phenol was 1. 00, 1.02, 3.
02 and 0.005, confirming the formation of the desired aromatic polyester. The product is melted to about 310 ° C. and a thread 0.1 to 0.15 mm in diameter and 100 mm long is drawn. Hang a 50-gram weight on the tip of the thread and put it in the air bath. Airbus 3 per minute
The temperature is raised at a rate of ° C to measure the temperature at which the yarn abruptly extends or the temperature at which the yarn breaks. This temperature can be used as a measure of heat resistance. 178 ° C for this product.

Example 1-3 In the same autoclave as in Example 1-2, (3,3'-diphenyl-4,4'-diacetoxy) biphenyl 105.
6 g (0.25 mol), isophthalic acid 41.5 g (0.25 mol) and paraacetoxybenzoic acid 13
Charge 5.1 grams (0.75 mole). The product is obtained in the same manner as in Example 1-2 while blowing nitrogen gas from the gas blowing port. The product has a number average molecular weight of 11,
500, and the heat resistant temperature is 179 ° C.

Example 2 In the same apparatus as in Example 1-2, (3,3'-diphenyl-
5,4'-diacetoxy) biphenyl 52.8 g (0.125 mol), 1,4-diacetoxy-2-phenylbenzene 33.8 g (0.125 mol), terephthalic acid 41.5 g (0.25) Mol) and 135.1 g (0.75 mol) of paraacetoxybenzoic acid. In the same manner as in Example 1-2, a melt anisotropic aromatic polyester having a number average molecular weight of 11,300 by the end group determination method can be obtained. The standard of heat resistance is 161 ° C, and the constituents are confirmed by the alkali decomposition method.

[0017]

According to the present invention, an aromatic polyester having excellent moldability and heat resistance can be provided.

Claims (1)

[Claims] 1. A polycondensate containing an aromatic dihydroxy compound (A), an aromatic dicarboxylic acid (B) and an aromatic hydroxycarboxylic acid (C) as main constituents, wherein (i) the aromatic dihydroxy compound (A) 50-100
The mol% is represented by the formula (1) Is (3,3′-diphenyl-4,4′-dihydroxy) biphenyl, and (ii) the aromatic dicarboxylic acid (B) is substantially equimolar to the aromatic dihydroxy compound (A), (iii) the aromatic hydroxycarboxylic acid (C) is more than 10 mol% and up to 400 mol% with respect to the aromatic dihydroxy compound (A), (iv) the average molecular weight of the polycondensate is 5,000 to 100,
An aromatic polyester characterized in that it is 000.