JPH0269518A - Production of aromatic polyester - Google Patents

Abstract

PURPOSE:To obtain the title polymer having excellent heat resistance and melt moldability by subjecting an oxycarboxylic acid, a bisphenol and an aromatic dicarboxylic acid to polycondensation until the pour temperature of the reaction product reaches a given value, grinding and heating the ground material in a solid phase to a high temperature under reduced pressure. CONSTITUTION:(A) 30-80mol% compound shown by formula I (X is group shown by formula II or formula III and >=50mol% X is group shown by formula II; R1 is H, formyl, acetyl, etc.; R2 is H, 1-6C alkyl or 6-18C aryl) is blended with (B) 10-35mol% compound shown by formula IV (Ar is bifunctional aromatic group; R3 is H, acetyl or benzoyl) and (C) 10-35mol% compound shown by formula V (Ar' is bifunctional aromatic group; R4 is OH, halogen, etc.) in a reactor and subjected to polycondensation at 270-350 deg.C. When the pour temperature of the reaction product reaches a temperature which is >=240 deg.C and >=20 deg.C lower than the polycondensation temperature, contents in the reactor are recovered in a molten state, ground into <=3mm particle diameter and treated in a solid phase as it is, at 250-370 deg.C in an inert gas atmosphere or under pressure for 1-20 hours to give the aimed compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an aromatic polyester having excellent heat resistance and good melt moldability.

[Conventional technology]

Attempts to obtain heat-resistant polyesters have been made for a long time, and there is much knowledge about aromatic polyesters made of aromatic dicarboxylic acids and aromatic diphenols, and aromatic polyesters obtained from aromatic oxycarboxylic acids.

Suspension polymerization, interfacial polymerization, solution polymerization, and bulk polymerization are known methods for producing aromatic polyesters, but the former three require post-processing, such as solvent removal, polymer washing,
There are problems such as drainage load. Although bulk polymerization is economically preferable, the equilibrium constant of the polycondensation reaction of polyester is smaller than that of polyamide, so in order to proceed with the polycondensation reaction, it is necessary to raise the reaction temperature or conduct the reaction under reduced pressure to eliminate by-products. I needed to find a way to quickly remove it. In particular, since heat-resistant polyester requires reaction at high temperatures, it is difficult to obtain the polymer in a stable state. In addition, low-boiling compounds and unreacted raw materials generated during polymerization may remain in the polyester and vaporize during molding, polluting the environment, or may gradually be generated when molded products are made, destroying the product structure.

[Problem to be solved by the invention]

In view of the current situation, an object of the present invention is to provide a method for stably producing an aromatic polyester having excellent heat resistance and good moldability, especially melt moldability, with uniform quality and low boiling point substances. .

[Means to solve the problem]

That is, the present invention provides compounds represented by the following formulas (A), CB) and (G) for producing an aromatic polyester by a solvent-free bulk polycondensation method substantially during polycondensation.
A) 30 to 80 mol%, (B) 10 to 35 mol%, and (C) 10 to 35 mol% in a method for producing an aromatic polyester by mixing the mixture and charging it into a reaction tank and subjecting it to polycondensation, The polycondensation reaction is carried out at 270 to 350°C, and the flow temperature of the aromatic polyester produced is 240°C.
When the temperature reaches 20°C or more lower than the polycondensation temperature, the aromatic polyester contained in the reaction tank is recovered in a molten state, pulverized into particles with a particle size of 3 mm or less, and the surface phase is The present invention relates to a method for producing aromatic polyester, which is characterized in that the aromatic polyester is treated as it is at 250 to 370° C. in an inert gas atmosphere or under reduced pressure for 1 to 20 hours.

(A) R+O-X C0OR* Yes, R1 is selected from hydrogen, formyl group, acetyl group, propionyl group, benzoyl group, R1 is hydrogen, alkyl group having 1 to 6 carbon atoms, oryl group having 6 to 18 carbon atoms selected from. ) (B) RsO-Ar 0Rs (Ar is a divalent aromatic group. R3 is selected from hydrogen, an acetyl group, a propionyl group, and a benzoyl group.) (C) R,C0-Ar'-COR.

(However, Ar' is a divalent aromatic group, and Ar' is a divalent aromatic group. R4
is selected from hydroxyl group, OR, and halogen; R is hydrogen;
It is selected from alkyl groups having 1 to 6 carbon atoms and aryl groups having 6 to 18 carbon atoms. ) The compounds represented by the above formulas (A), (B) and (C) are (A) 30 to 80 mol% and (B) 10 to 35 mol%.
The aromatic polyester obtained by mixing 10 to 35 mol% of , and (C) and polycondensing the mixture is crystalline and has excellent mechanical properties, chemical resistance, and heat resistance. .

A more preferable mixing ratio of each compound is (A) 40 to 70
mol%, (B) 15-30 mol%, and (C) 15-3
It is 0 mol%. Furthermore, some exhibit anisotropy in the molten state and also have good melt formability.

When the proportion of compound (A) exceeds 80 mol%, the aromatic polyester often has a portion that does not melt when heated, resulting in significantly poor melt processability, and when the proportion of compound (A) is less than 30 mol%, the aromatic polyester has low crystallinity, which is not desirable. If it is less than 50 mol%, the crystallinity of the target aromatic polyester decreases, which is not preferable.

°Compound\l/J When the proportion of (B) and (C) is between 10 and 35 mol%, the aromatic polyester exhibits balanced characteristics.

In addition, the molar ratio of compounds (B) and (C) at the time of preparation is 90 to 115:100 from the viewpoint of polymer physical properties, especially thermal stability.
, preferably 100-110:100.

Examples of compounds represented by formula (A) include p-hydroxybenzoic acid, p-formoxybenzoic acid, p-acetoxybenzoic acid, p-probyloxybenzoic acid, methyl p-hydroxybenzoate, propyl p-hydroxybenzoate, and p-hydroxybenzoic acid. −
Phenyl hydroxybenzoate, benzyl p-hydroxybenzoate, methyl p-acetoxybenzoate, 2-hydroxy-6-naphthoic acid, 2-acetoxy-6-naphthoic acid, methyl 2-hydroxy-6-naphthoate, 2-hydroxy -6-naphthoic acid phenyl, 2-acetoxy-6
-Methyl naphthoate and the like. Particularly preferred compounds are p-hydroxybenzoic acid and/or ester-forming derivatives thereof.

Examples of the compound represented by formula (B) include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl,
4.4'-dihydroxybenzophenone, 4,4°-
Dihydroxydiphenylmethane, 4.4°-dihydroxydiphenylethane, 4°4°-dihydroxydiphenyl ether, 2.2-bis(4-hydroxyphenyl)
Propane, 4°4°-dihydroxydiphenylsulfone, 4,4-dihydroxydiphenylsulfide, 2.6
-dihydroxynaphthalene, 1,4-dihydroquinaphthalene, 1,5-dihydroxynaphthalene, 14-diacetoxybenzene, 1,3-diacetoxybenzene, 4
, 4゛-diprobionyloxydiphenyl, 2.6-
Examples include dicarboxynaphthalene and the like, and nuclear substituted products of these alkyl, aryl, alkoxy, and halogen groups.

Particularly preferred compounds are those selected from hydroquinone, 4,4'-dihydroxydiphenyl, and/or ester-forming derivatives thereof.

Examples of compounds represented by formula (C) include terephthalic acid, isophthalic acid, 4,4'-dicarboxydiphenyl,
1.2-bis(4-carboxyphenoxy)ethane, 2
．． 6-dicarboxynaphthalene, l,4-dicarboxynaphthalene, 5-dicarboxynaphthalene, dimethyl terephthalate, dimethyl isophthalate, diphenyl terephthalate, diphenyl isophthalate, terephthalic acid dichloride, isophthalic acid dichloride, 4,4゜dimethoxy Carbonyldiphenyl, 2,6-dimethylcarbonylnaphthalene, 1,4-dichlorocarbonylnaphthalene, 1
, 5-diphenoxycarbonylnaphculene, and nuclear substituted products of these alkyl, aryl, alkoxy, and halogen groups.

The aromatic polyester of the present invention can be obtained by subjecting a mixture of the compounds represented by (A), (B) and (C) above to a polycondensation reaction in a polymerization tank. Preparation may be done in bulk or in parts. The reaction can be carried out under an inert gas atmosphere, such as nitrogen, at normal pressure, reduced pressure, or a combination thereof, and the process can be carried out batchwise, continuously, or in a combination thereof.

Note that prior to the polycondensation reaction, a reaction (for example, an esterification reaction) that changes the compounds represented by formulas (A), (B), and (C) into a compound that is more susceptible to polycondensation reactions may be carried out. It is also possible to carry out the polycondensation reaction in a different or the same reaction tank and then carry out the polycondensation reaction.

The temperature of the polycondensation reaction in the present invention is 270 to 350°C
is preferable, and more preferably 280 to 330°C.

When the temperature is lower than 270℃, the reaction progresses slowly, and when the temperature is lower than 350℃
If the temperature is exceeded, the resulting polymer is often prone to coloring.
A multi-step reaction temperature may be adopted, and in some cases, the aromatic polyester, which is the reaction product, may be extracted in a molten state during heating or as soon as the maximum temperature is reached.
It can also be collected.

Ge, Sn, and Tt as catalysts for polycondensation reactions.

Compounds such as S b s Co s M n can also be used.

A known shape of the reaction tank can be used. In the case of a vertical stirring tank, multi-stage turbine blades, paddle blades, or double helical blades are preferred; in the case of a horizontal stirring tank, blades of various shapes, such as lenses, are installed perpendicularly to the l-axis or the two-wheeled stirring shaft. It is preferable to have blades, spectacle blades, oblong flat plate blades, etc. It is also good to have twists on the blades to improve the stirring performance and feeding mechanism.

The reaction tank is heated by a heating medium, gas, or electric heater, but it is preferable to also heat the stirring shaft, blades, baffle plates, etc. for the purpose of uniform heating.

When the reaction tank is divided into multiple stages or partitioned, the reaction temperature at the final stage is the polycondensation temperature as defined in the present invention.

The time for the polycondensation reaction should be appropriately determined depending on the reaction conditions, etc., but at the reaction temperature 0. 5 to 5 hours is preferred.

What is important in the present invention is that the flow temperature of the polyester obtained by the polycondensation reaction is at least 240°C and at least 20°C lower than the polycondensation temperature. More preferably, the flow temperature of the obtained polyester is 260°C or higher and 25°C or more lower than the polycondensation temperature. If the flow temperature is not 240°C or higher, the molecular weight of the polyester is insufficient and the molding process is difficult. , there are problems with physical properties. When performing solid phase polymerization, polyesters fuse together and a large amount of by-products are produced, which is economically undesirable.If the flow temperature is close to the polycondensation temperature, the viscosity of the polyester becomes high (and recovery becomes difficult). Otherwise, stirring and mixing properties deteriorate, and the thermal stability of the polymer is adversely affected due to non-uniform heating.

It is preferable to take out the polyester in a molten state in an inert gas atmosphere, but it may also be taken out in air if the moisture content is low.

Mechanisms for extracting polyester in a molten state include an extruder,
A gear pump is considered, but it may also be just pulp. Depending on the purpose, the extracted material can be pulverized using a strand cutter, sheet cutter, pulverizer, etc.

A solvent, a lubricant, a stabilizer, and an additive may be added to the polycondensation system on the premise that the melt viscosity does not change significantly.

Although the aromatic polyester recovered in a molten state can be used as it is, solid phase polymerization based on the present invention is desirable from the standpoint of removing unreacted raw materials and improving physical properties.

The obtained aromatic polyester is mechanically pulverized into particles with a particle size of 3 mm or less, preferably 0.5 m or less, and is crushed in a solid state at 250 to 370°C under an inert gas atmosphere or under reduced pressure. It is preferable to carry out the treatment at the highest temperature for 1 to 20 hours, more preferably at the highest temperature for 2 to 10 hours.

When the particle size of the particles exceeds 3111 m, the polymerization rate and diffusion time of unreacted raw materials and new by-products generated as a result of the reaction differ between the surface layer and the interior, so it is difficult to widen the molecular weight distribution or remove them. Things like not being able to remove enough things that should be done, etc.
This is not preferable because it causes problems in physical properties.

The heating rate and treatment temperature during solid phase polymerization must be selected so as not to fuse the aromatic polyester particles. When fusion occurs, the surface area decreases and polycondensation reactions and removal of low-boiling substances become slow, which is not preferable.

The treatment temperature for solid phase polymerization is 250~250℃ without fusion.
It is effective to perform the treatment at 370° C. under an inert gas atmosphere or under reduced pressure. At temperatures below this temperature range, the reaction is slow, time-consuming, and uneconomical; at temperatures above 370°C, decomposition reactions occur, which is not desirable.
It is recommended to use an inert gas or reduced pressure (in case of reduced pressure, the gas leaking from the outside should be an inert gas.If air, especially oxygen, is present, the polyester will be oxidized, resulting in a decrease in physical properties and coloring, which is not good.) The gas and trowel are selected from nitrogen, hydrogen, helium, argon, and carbon dioxide. Ammonia, amines, and waterweed are undesirable because they cause decomposition of the polyester.

Known dryers, reactors, mixers, electric furnaces, etc. can be used as equipment for solid phase polymerization.

[Example] Examples of the present invention will be shown below, but the present invention is not limited thereto.

The flow temperature of polyester is an index representing the melt fluidity, and its measurement method is a capillary rheometer.
(■ Shimadzu Flow Tester CFT-51O0 model)
The sample resin was heated and melted at a heating rate of 4°C/min, and the inner diameter
l11, the melt viscosity is 48. ．． It is expressed as the temperature at a point indicating 000 poise.

Furthermore, since the polyester in the present invention is crystalline, it is often difficult to measure the molecular weight because there is no solvent in which it can be uniformly dissolved, so the discussion will be based on the flow temperature as a guideline for molecular weight.

Measurement of optical anisotropy was performed using a particle size of 25 mm placed on a heating stage.
A sample resin powder of 0 μm or less was heated at 25'C/min under polarized light and visually observed.

The weight reduction was performed using a thermobalance TG-DTA standard model manufactured by Rigaku Denki ■, and approximately 20 mg of sample resin with a particle size of 250 μm or less was measured.
was heated in air at a temperature increase rate of 10° C./min, and the change in weight over time was measured.

Further, from this measured value, the temperature at which the weight M decrease rate was 2.5% with respect to the original IT was determined.

Tensile testing of molded products was conducted in accordance with ASTM D-638.
Using a dumbbell-shaped test piece, number of samples: 6, marked line open circuit #40I
III+ at a pulling speed of 5 ma+/min.

Heat distortion temperature is 18.6 according to ASTM D-648.
Measured under a pressure of kg/CTA. The whiteness of the molded product was measured using a plate-shaped molded product with a size of 40 m x 40 mm using a digital color difference meter ND-101-DP manufactured by Nihon Heavy Industries Ltd. The measured value was determined by setting pure black to O1 and pure white to 100, and correcting it with a standard titanium oxide product (whiteness 94.5).

Example 1 1,152 p-acetoxybenzoic acid was placed in a polymerization tank having three-stage paddle blades and a small gap between the tank wall and the stirring blade.
g (6,40 mol), 491 g (1,82 mol) of 4.4 diacetoxydiphenyl, and 436 g (1,80 mol) of 4,4°-dicarboxydiphenyl were charged, and the contents were placed under a nitrogen gas atmosphere. 1 from 200℃ while stirring
The temperature was raised at a rate of °C/min, and polymerization was carried out at 320'C for 2 hours and 20 minutes.

During this time, acetic acid produced as a by-product due to the polycondensation reaction was continued to be distilled off. The polymer was sampled during the polymerization, and its flow temperature was measured. Flow temperature in 1 hour at 320℃ is 260℃
The temperature was 282°C in 2 hours.

A valve at the bottom of the polymerization tank was opened, and the polyester was taken out into a takeout box under a nitrogen atmosphere. The polyester could be easily extracted in a molten state, and when the reaction tank was later disassembled, almost no polyester was found to be attached to the tank walls or valve section. The yield of the obtained polyester was 1,462g.
(99.2% of the theoretical yield).

The taken out polyester is milled to an average particle size of 1ffIIn.
After grinding into the following particles, the flow temperature was measured.
The temperature was 290°C, and optical anisotropy was observed in the 78 melting state of 325°C or higher.

Polyester particles with an average particle size of 1 ㎜ or less were placed in a stainless steel rotary kiln with an internal capacity of 122 mm, heated from room temperature to 200°C in 1 hour under a nitrogen atmosphere, and then heated from 200°C to 200°C.
The temperature was raised to 70°C over 4 hours, and the temperature was kept at 270°C for 3 hours, and then taken out. The weight loss during solid phase polymerization was 1.1%.

The polymer powder was insoluble in xylene, tetrachloroethane, chloroform, a 6:4 mixture (by volume) of phenol and tetrachloroethane, and m-cresol. The flow temperature of this polymer was 337°C. As a result of wide-angle X-ray diffraction, it was confirmed that it was crystalline. This polymer shows no weight loss up to 300°C and has a weight loss of 1. The temperature at which weight 1 reduction rate was 0% was 445°C, and even at 500°C, the weight loss was less than 2%.

It was.

600g of this polyester, diameter 13μm, average length 5
A mixture consisting of 400 g of 0 μm glass fiber is 350
It was possible to granulate well at ℃, and pellets were obtained. This pellet could be successfully injection molded using an injection molding machine Neomat N47/28 manufactured by Sumitomo Heavy Industries Ltd. at a cylinder temperature of 355° C., and a test piece was obtained. The obtained test piece had a tensile strength of 1,210 kg/d and an elastic modulus of 7.2X10'
kg/cd, heat distortion temperature of 283° C., and whiteness of 72.

Comparative Example 1 When the polycondensation at 320° C. in Example 1 was continued for an additional 2 hours, the stirring load became abnormally large and the stirring was stopped. The flow temperature of the polyester at this time was 311°C, and it could not be extracted from the reaction tank.

Comparative Example 2 When the polycondensation temperature reached 320"C in Example 1, polyester was extracted in the same manner as in Example 1. The flow temperature of the polyester at this time was 226"C.

This polymer showed a weight loss of 1.7% up to 250°C, and the temperature at which it showed a weight loss rate of 2.5% with respect to the original weight was 277°C.

This polyester was pulverized to less than Is and subjected to solid phase polymerization using the same equipment and under the same conditions as in Example 1, but the entire product had been remelted and the flow temperature had not risen to the required molecular weight of 240'C. In addition, the temperature was increased from 200°C to 270°C over 12 hours by slowing the rate of temperature rise, and after being held at 270°C for 3 hours, it was taken out.

Although the sample remained as a powder and there was no fusion, the loss of heavy N during solid phase polymerization was as high as 6.8%.

The flow temperature of the polyester was 331°C.

After this treatment, a mixture consisting of 600 g of polymer and 400 g of glass fibers with a diameter of 13 μm and an average length of 50 μm was granulated at 350″C, but the discharge of the strands was unstable compared to Example 1, causing problems. Met.

Comparative Example 3 A thermal analysis of the polyester taken out in the molten state in Example 1 showed no weight loss up to 250°C, but a weight loss rate of 1.0% relative to the original weight. The temperature was 395°C, and the temperature showing a weight loss rate of 2.5% was 412°C. From this, it is clear that by performing the treatment of Example 1, low boiling point substances can be removed.

Example 2 720 g of p-acetoxybenzoic acid was prepared in the same manner as in Example 1.
(41O0 mol), 4,4°-diacetoxydiphenyl 546g (21O2 mol), terephthalic acid 332g
(21O0 mol) was charged and subjected to polycondensation reaction, and the flow temperature of the reactant was 320℃, which was 286℃ by sampling.
The contents were extracted after 2 hours. It was possible to recover light yellowish brown polyester in a molten state without any problems.

The yield of polyester was 1.103 g (99.2% of the theoretical yield).

Optical anisotropy in the molten state of this polymer was observed above 325°C, and it did not show any weight loss up to 250°C, and the temperature at which it showed a weight loss rate of 2.5% relative to the original weight was 410°C. Ta.

After pulverizing this polyester into particles having an average particle size of 1 mm or less using a pulverizer, solid phase polymerization treatment was performed using the same equipment and under the same conditions as in Example [1]. The weight loss during solid state polymerization was 0.9%, and the flow temperature was 336°C.

This polymer was insoluble in each of the same solvents as in Example 1. This polymer was found to be crystalline by wide-angle X-ray diffraction.

This polymer shows no weight loss up to 300°C, and the temperature at which it shows a weight loss rate of 1.0% relative to the original weight is 455°C.
Even at 500°C, the weight loss was less than 2%.

This polymer and glass fibers were mixed and granulated in the same manner as in Example 1 except that this polymer was used.
Injection molded with 'C. The granulation and moldability are good, the tensile strength of the test piece is 1.180 kg/cm, and the elastic modulus is 6.
9.times.10'kg/cd, heat distortion temperature: 285.degree. C., whiteness: 72.

Example 3 In the same reaction tank as in Example 1, p-hydroxybenzoic acid 607
g (4.40 mol), 406 g of terephthalic acid dichloride
(2100 mol), xylene 1.8 as reaction medium
1 and stir vigorously under a nitrogen atmosphere.
The reaction was carried out for 1 hour at 130°C, 1 hour at 130°C, and 4 hours at 140°C. Hydrogen chloride produced as a by-product in the reaction was neutralized with an aqueous solution of caustic soda. The reaction rate was 92%. After this, 323g of 2,6 dihydroxynaphthalene (21O2
mol) and 224 g (2.20 mol) of acetic anhydride were charged, and an acetylation reaction was carried out at 140'C for 4 hours.

The temperature was raised to 320°C at a heating rate of 2°C/min, xylene, acetic anhydride, and acetic acid were removed, and polycondensation was performed substantially without solvent. 2i of contents by sampling on the way! L dynamic temperature is 2
When the valve at the bottom of the reaction tank was opened 20 minutes after the temperature reached 75°C, the polyester could be extracted without any problem. The flow temperature of the polyester taken out was 282°C.

The yield of polyester is lLOOg (9% compared to the theoretical yield).
Yuko's polymer, which was 9.3%), exhibited optical anisotropy in the molten state at temperatures above 330°C, and showed no weight loss up to 250°C, resulting in a weight loss of 2.5% relative to the original weight. The temperature indicating the rate is 425'
It was C.

After pulverizing this polyester into particles with an average particle size of 1 dish or less using a pulverizer, the polyester was placed in a stainless steel container with a thickness of approximately 10+ nm, placed in an electric furnace, and heated from room temperature to 200 nm under a nitrogen atmosphere.
'C in 1 hour, 200℃ to 270℃
The temperature was raised from 270°C to 360°C over 3 hours, and the temperature was maintained at 360°C for 3 hours before being taken out. The weight loss during solid phase polymerization was 3.6%, and the flow temperature of the resulting polyester was 395°C.

This polymer, as in Example 1, was insoluble in each solvent. This polymer was found to be crystalline from wide angle X&i+ diffraction.

This polymer does not show a decrease in fK up to 300°C, and the temperature at which it shows a weight loss rate of 1.0% relative to the original weight is 485°C.
Met.

This polymer and glass fiber were mixed in the same manner as in Example 1 except that this polymer was used, granulated at 360"C, and injection molded at 370"C. Pelletability and moldability were good, and the test Tensile strength of piece 1 050 kg/cJ, modulus of elasticity 5, 4 x 10' kg/ci, heat distortion temperature 3
21'C1 whiteness was 71.

Example 4 P-acetoxybenzoic acid 576 was added to the same reaction tank as Example 1.
g (3,20 mol), 2-acetoxy-6-naphthoic acid 644 g (2,80 mol), 14-diacetoxy-2
426 g of methylbenzene (5 g mol of 21O) and 332 g of terephthalic acid (0 mol of 21O) were charged, and the contents were heated at a rate of 167 minutes from 200°C while stirring under a nitrogen gas cloud, and polymerized at 310°C for 2 hours and 50 minutes. I let it happen.

During this period, acetic acid produced as a by-product of the polycondensation reaction was continued to be distilled off. During the polymerization, a sample of the polymer was taken, and its flow temperature was measured. Flow temperature in 1 hour at 310℃ is 242
°C, 261'C in 2 hours, 272'C in 2 hours 30 minutes
Therefore, the valve at the bottom of the polymerization tank was opened and the polyester was extracted into a removal box under a nitrogen atmosphere.The polyester was easily extracted in a molten state.

The yield of polyester was 1,357 g (99.2% of the theoretical yield) and the flow temperature was 279°C.

This polymer exhibits optical anisotropy in the molten state at temperatures above 320°C, shows no weight loss up to 250"C, and the temperature at which it shows a weight loss rate of 2.5% relative to the original weight is 435°C.
Met.

This polyester was pulverized into particles having an average particle size of 1M or less using a pulverizer, and then subjected to solid phase polymerization using the same apparatus and under the same conditions as in Example 1. The weight loss during solid-state polymerization was 1.5%, and the flow temperature was 337°C. The polymer was insoluble in the same solvents as in Example 1, and wide-angle X-ray diffraction showed that it was crystalline. It was confirmed.

This polymer shows no weight loss up to 300°C, and the temperature at which it shows a weight loss rate of 1.0% relative to the original weight is 480°C.
Even at 500°C, the weight loss was less than 2%.

This polymer and glass fibers were mixed and granulated in the same manner as in Example 1 except that this polymer was used.
Injection molded at ℃. The granulation and moldability are good, and the tensile strength of the test piece is 1,400 kg/cj11 and the modulus of elasticity is 8.3
10'kg/cd, heat distortion temperature 280℃, whiteness 73
Met.

〔Effect of the invention〕

According to the present invention, it is possible to stably produce a uniform, high-quality aromatic polyester containing few low-boiling substances.

The aromatic polyester obtained by the present invention can be used not only by forming it into fibers, films, and various shapes, but also polyester and glass fiber, mica, talc, silica, potassium titanate, wollastonite, The composition consisting of calcium carbonate, quartz, iron oxide, graphite, carbon fiber, etc. has mechanical properties, electrical properties,
It has excellent chemical and oil resistance, so it can be used for mechanical parts, electrical,
It can be used for electronic parts and automobile parts.

Claims (1)

[Scope of Claims] Compounds represented by the following formulas (A), (B) and (C) are
A) 30 to 80 mol%, (B) 10 to 35 mol%, and (C) 10 to 35 mol% in a method for producing an aromatic polyester by mixing the mixture and charging it into a reaction tank and subjecting it to polycondensation, The polycondensation reaction is carried out at 270 to 350°C, and the flow temperature of the aromatic polyester produced is 240°C.
When the temperature reaches the temperature above and 20°C or more lower than the polycondensation temperature, the aromatic polyester contained in the reaction tank is recovered in a molten state and pulverized into particles with a particle size of 3 mm or less,
A method for producing an aromatic polyester, which comprises treating the aromatic polyester in a solid state at 250 to 370°C under an inert gas atmosphere or under reduced pressure for 1 to 20 hours. (A) R_1O-X-COOR_2 (However, X includes ▲mathematical formula, chemical formula, table, etc.▼ and ▲
There are mathematical formulas, chemical formulas, tables, etc.▼, and more than 50 mol% of them are ▲There are mathematical formulas, chemical formulas, tables, etc.▼. R_1 is selected from hydrogen, a formyl group, an acetyl group, a propionyl group, and a benzoyl group, and R_2 is selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 18 carbon atoms. ) (B) R_3O-Ar-OR_3 (However, Ar is a divalent aromatic group. R_3 is hydrogen,
Selected from acetyl group, propionyl group, and benzoyl group. ) (C)R_4CO-Ar'-COR_4 (However, Ar' is a divalent aromatic group, and more than 50 mol% of Ar' is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas, There are tables, etc.▼, and/or ▲There are mathematical formulas, chemical formulas, tables, etc.▼.R_4 is a hydroxyl group,
OR_5 is selected from halogen, and R_5 is selected from hydrogen, alkyl having 1 to 6 carbon atoms, and aryl group having 6 to 18 carbon atoms. )