JP2009161696A - Method of preparing copolymerized aromatic polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preparing an aromatic polyester by copolymerizing a 6,6'-(alkylenedioxy)-2-naphthoic acid component from which the generation of by-products such as diethylene glycol is suppressed. <P>SOLUTION: The method of preparing the copolymerized aromatic polyester comprises the step of reacting a 6,6'-(alkylenedioxy)di-2-naphthoic acid (ANA) component, another aromatic dicarboxylic acid and ethylene glycol, wherein the 6,6'-(alkylenedioxy)di-2-naphthoic acid or its ester-forming derivative used in the method has a pH of 4.5-7.5 when processed into its 20 wt.% water slurry. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a copolymerized aromatic polyester in which a part of an aromatic dicarboxylic acid component is a 6,6 ′-(alkylenedioxy) di-2-naphthoic acid component and a glycol component is an ethylene glycol component.

  An aromatic polyester composed of an aromatic dicarboxylic acid typified by polyethylene terephthalate or polyethylene-2,6-naphthalate and a glycol component has excellent mechanical properties and chemical properties. Widely deployed in molded products. However, there is a strong demand for higher performance from the market, and improvements are desired.

  Under such circumstances, Patent Documents 1 to 4 are ester compounds of 6,6 ′-(alkylenedioxy) di-2-naphthoic acid as a higher performance polyester than polyethylene-2,6-naphthalate. Polyalkylene-6,6 ′-(alkylenedioxy) di-2-naphthoate obtained from diethyl-6,6 ′-(alkylenedioxy) di-2-naphthoate has been proposed. And according to these patent documents, it is disclosed that such a polymer is very excellent in dimensional stability and can express very high rigidity.

  However, according to the study by the present inventors, the polymers described in these publications have a very high melting point and excessive crystallinity, so when trying to form a film, particularly a film, etc. It has been found that the melt-extrusion process is destabilized and easily broken during stretching. In these patent documents, polyethylene-6,6 '-(ethylenedioxy) di-2-naphthoate having a very high crystallinity and a very high melting point of 294 ° C. is specifically presented.

JP-A-60-135428 JP-A-60-212420 JP 61-145724 A JP-A-6-145323

  The present inventors have studied a new polymer that replaces polyethylene terephthalate, polyethylene-2,6-naphthalate and polyethylene-6,6 ′-(ethylenedioxy) di-2-naphthoate. When-(alkylenedioxy) di-2-naphthoic acid is used as a copolymerization component, the same Young's modulus has a smaller coefficient of humidity expansion than polyethylene terephthalate or polyethylene-2,6-naphthalate, and polyethylene-6,6 '-( It was found that a polymer having excellent dimensional stability against changes in temperature and humidity having a low temperature expansion coefficient compared to (ethylenedioxy) di-2-naphthoate was obtained, and was filed earlier.

As a result of further research, by-products such as diethylene glycol may be produced in large quantities even if the polymerization reaction is carried out under the same catalyst and conditions, and it is difficult to stably produce polyester of uniform quality. Found that there is a potential problem.
Therefore, an object of the present invention is to stably produce a high-quality and stable copolymerized aromatic polyester obtained by copolymerizing 6,6 ′-(alkylenedioxy) di-2-naphthoic acid having excellent dimensional stability. It is to provide a manufacturing method that can be used.

  As a result of diligent research to solve the above problems, when the raw material of the 6,6 ′-(alkylenedioxy) di-2-naphthoic acid component is made into a water slurry and the pH at that time is in a specific range, The present inventors have found that generation of certain diethylene glycol can be suppressed and have reached the present invention.

Thus, according to the present invention, the object of the present invention is to provide 6,6 ′-(alkylenedioxy) di-2-naphthoic acid represented by the following formula (I) as an acid component or an ester-forming derivative thereof 5-80. A method for producing a copolymerized aromatic polyester comprising reacting 20% to 95% by mole of an aromatic dicarboxylic acid represented by the following formula (II) or an ester-forming derivative thereof with ethylene glycol as a glycol component:
6,6 ′-(alkylenedioxy) di-2-naphthoic acid or an ester-forming derivative thereof having a pH in the range of 4.5 to 7.5 when 20% by weight in water slurry is used A method for producing a copolymerized aromatic polyester is provided.

（上記式（Ｉ）中のＲ^１は、炭素数１〜１０のアルキル基であり、上記式（ＩＩ）中のＲ^２は、フェニレン基またはナフタレンジイル基である。）

(R ¹ in the above formula (I) is an alkyl group having 1 to 10 carbon atoms, and R ² in the above formula (II) is a phenylene group or a naphthalenediyl group.)

  As a preferred embodiment of the present invention, 6,6 ′-(alkylenedioxy) di-2-naphthoic acid or an ester-forming derivative thereof is sulfuric acid, chlorine and The total bromine ion is 15 ppm or less based on the weight of the slurry, and the aromatic dicarboxylic acid represented by the formula (II) or its ester-forming derivative is terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic An adjusting means for adjusting the pH of the water slurry to be in the range of 4.5 to 7.5, being at least one selected from the group consisting of acids, 2,7-naphthalenedicarboxylic acids and ester-forming derivatives thereof, The content of sodium and potassium elements based on the weight of the copolymerized aromatic polyester obtained. The method of copolymerizing the aromatic polyester comprising at least one of that from 1 in the range of 200ppm also provided.

  According to the present invention, a copolymerized aromatic polyester modified by copolymerizing a 6,6 ′-(alkylenedioxy) di-2-naphthoic acid component is produced in a monomer synthesis stage or a polycondensation reaction stage. By-products such as diethylene glycol can be suppressed, and as a result, a polymer having a high quality such as a melting point can be stably produced.

The method for producing the copolymerized aromatic polyester of the present invention will be described in detail below.
In the production method of the present invention, 6,6 ′-(alkylenedioxy) di-2-naphthoic acid represented by the above formula (I) or an ester-forming derivative thereof (hereinafter referred to as raw material A) is used as the acid component. And an aromatic dicarboxylic acid represented by the formula (II) or an ester-forming derivative thereof (hereinafter sometimes referred to as a raw material B), and ethylene glycol is reacted as a glycol component. Usually, the first reaction is an esterification reaction or transesterification reaction between an acid component and a glycol component, and the second reaction step is a polycondensation reaction of the obtained precursor.
At this time, what is important is that the ratio of the raw material A in the total acid component is 5 to 80 mol%, the ratio of the raw material B is 20 to 95 mol%, and the raw material A is 20% by weight. It is to use what has pH in the range of 4.5-7.5 when water-slurried.

  In the present invention, the 6,6 ′-(alkylenedioxy) di-2-naphthoic acid represented by the structural formula (I) is one in which the R portion is an alkylene group having 1 to 10 carbon atoms. 6,6 ′-(ethylenedioxy) di-2-naphthoic acid, 6,6 ′-(trimethylenedioxy) di-2-naphthoic acid and 6,6 ′-(butylenedioxy) di- 2-naphthoic acid component and the like are mentioned. Among these, from the viewpoint of the effect of the present invention, those having an even number of carbon atoms of R in the above general formula (I) are preferable, and in particular, 6,6 ′-(ethylenedioxy ) Di-2-naphthoic acid is preferred.

  Examples of the aromatic dicarboxylic acid represented by the structural formula (II) in the present invention include terephthalic acid, phthalic acid, isophthalic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, 4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 2,6 -Naphthalene dicarboxylic acid and 2, 7- naphthalene dicarboxylic acid are mentioned. Among these, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid are preferable, and 2,6-naphthalenedicarboxylic acid is particularly preferable from the viewpoint of easily maintaining mechanical properties and the like. preferable.

  In the present invention, the 6,6 ′-(alkylenedioxy) di-2-naphthoic acid represented by the structural formula (I) and the aromatic dicarboxylic acid represented by the structural formula (II) are as described above. An ester-forming derivative may be used. Specific examples of the ester-forming derivative include, for example, lower alkyl esters having 1 to 3 carbon atoms, and dimethyl ester and diethyl ester are particularly preferable.

  About the ratio of the raw material A and the raw material B in this invention, when the ratio of the raw material A is too small, or the ratio of the raw material B is too large, the effect by having copolymerized the raw material A is not fully expressed, If the proportion of the raw material A is too large or the proportion of the raw material B is too small, the effect of copolymerization of the raw material A becomes saturated, rather the melting point and crystallinity become too high, and molding such as stretching tends to be difficult. . A preferable ratio of the raw material A is 10 to 80 mol%, and further 15 to 75 mol%, and a preferable ratio of the raw material B is 20 to 90 mol%, and further 25 to 85 mol%. The glycol component is ethylene glycol from the viewpoint of the melting point and mechanical properties of the resulting polymer, preferably 90 mol% or more, more preferably 95 mol% or more, particularly 97 mol% or more of the glycol component. Is preferred.

  One of the features of the present invention is that the pH when the raw material A is made into a 20% by weight water slurry is managed as an index. Specifically, the pH of the water slurry is 4 to 7.5, preferably 4.5 to 7, and by adjusting the pH when the raw material A is a water slurry to be in this range, To suppress the rapid increase of diethylene glycol, and the desired melting point of the resulting copolymerized aromatic polyester can be reduced without significant reduction.

  The reason why the pH may be outside the above range when the raw material A is an aqueous slurry is that the raw material A is synthesized from 2-hydroxy-6-naphthoic acid as described in Patent Documents 1 to 3. In this case, chlorine, bromine, or sulfur compounds are used, or the aqueous solution of potassium or sodium salt compound, which is a water-soluble compound as raw material A or its precursor, is acidified by acid such as sulfuric acid. It is thought that this is because the components remain. That is, halogen elements typified by chlorine and bromine, or free anion components such as sulfate radicals promote the generation of by-products such as diethylene glycol, and by adjusting the pH within the above range, such problems can be avoided. It is thought that it was solved. Accordingly, when the pH is less than the lower limit or exceeds the upper limit, washing with water or the like may be repeated until the pH falls within the range. In addition, since such a problem did not appear as a problem in the raw material B represented by the structural formula (II) such as terephthalic acid or naphthalenedicarboxylic acid, the raw material A represented by the formula (I) was used. It can be said that it solved a unique problem. From such a viewpoint, it is preferable that the amount of anions as free acids contained in the raw material A is small, and the total of sulfuric acid, chlorine and bromine ions in the slurry by the measurement method described later is 15 ppm or less, It is preferably 10 ppm or less, particularly 5 ppm or less.

  By the way, in the manufacturing method of this invention, a potassium compound or a sodium compound is contained in 1 ppm or more and 200 ppm or less in the range of 5 ppm or more and 150 ppm or less by the total element amount on the basis of the weight of the copolymerized aromatic polyester obtained. It is preferable that the copolymer aromatic polyester obtained has high heat resistance while suppressing by-products such as diethylene glycol. In particular, in order to further suppress the formation of by-products such as diethylene glycol, a potassium compound or a sodium compound is contained in an amount of 40 ppm or more, preferably 50 ppm or more, based on the weight of the copolymerized aromatic polyester obtained in the amount of those elements. It is preferable. On the other hand, from the viewpoint of increasing the heat resistance of the copolymer aromatic polyester obtained, the copolymer aromatic obtained by using potassium element or sodium compound in the amount of these elements while keeping the pH of the raw material A above 5 or more. Based on the weight of the polyester, it is preferably 30 ppm or less, more preferably 20 ppm or less. That is, only by adjusting the ratio of the potassium compound or sodium compound, even if diethylene glycol can be suppressed, the heat resistance is reduced, or even if the heat resistance is good, there is a large amount of diethylene glycol. Therefore, both characteristics can be provided at a higher level.

  Examples of the potassium compound and sodium compound in the present invention include respective hydroxides, acetates, carbonates and the like, and most preferred is 6,6 ′-(alkylenedioxy) di-2-naphtho. Mention may be made of compounds that are produced during the production of the acid and remain as salts in 6,6 ′-(alkylenedioxy) di-2-naphthoic acid. Usually, potassium salts and sodium salts are removed so as not to remain for purification, but by leaving potassium compounds and sodium compounds within the above ranges, 6,6 ′-(ethylene The production process of (oxy) di-2-naphthoic acid can be simplified, the amount of sodium and potassium compounds newly added in the production process of the copolymerized aromatic polyester can be reduced, and the addition process itself can be omitted. It also leads to doing things.

  By the way, the number of moles of the ethylene glycol component to be present in the first reaction step is 1.5 to 10 times, further 2 to 6 times, particularly 3 to 5 times the number of moles of all acid components. Is preferred. In particular, by increasing the molar ratio of ethylene glycol and acid component in the reaction compared to the synthesis reaction of polyethylene terephthalate or polyethylene naphthalate, 6,6 ′-(alkylenedioxy) di-2-2, which hardly dissolves in the glycol component. The fluidity of the reaction system can be increased by diluting and dispersing naphthoic acid or its ester-forming derivative.

  In addition, it is preferable that the first reaction is gradually heated and finally performed in a range up to 260 ° C. In order to suppress the production of the by-product diethylene glycol component, it is preferable to complete the reaction at a temperature as low as possible. In the present invention, the reaction can be carried out under normal pressure by the presence of the aforementioned potassium compound or sodium compound, but the reaction may be carried out under pressure to further increase the productivity, or the manganese compound. A catalyst known per se such as calcium and calcium compounds may be used, and a method of further increasing the reactivity by adding a polymerization catalyst such as a titanium catalyst typified by tetrabutyl titanate as an esterification or transesterification catalyst is also possible. .

  As a method to further increase the reactivity, a precursor obtained by esterifying or transesterifying raw material A and ethylene glycol in advance is prepared as a seed monomer, and new raw material A is added and esterified based on the monomer. There is also a method of performing a reaction or transesterification reaction. Such a method leaves a part of the reacted copolymer monomer and uses it for the synthesis reaction of the next copolymer monomer, so that a new process is not required, and the reaction time can be further shortened. There is also an advantage that generation and the like can be suppressed.

  Moreover, when using a titanium compound as a catalyst for the first reaction, based on the weight of the copolymerized aromatic polyester, it is used in the range of 5 to 150 ppm, further 10 to 100 ppm, and further 15 to 50 ppm in terms of titanium element amount, It is preferable from the viewpoints of reactivity and heat resistance and hue of the resulting polymer. Specific examples of the titanium compound as the polycondensation catalyst include tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-tert-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, and the like. Enyl titanate, tetrabenzyl titanate, lithium oxalate titanate, potassium oxalate titanate, ammonium oxalate titanate, titanium oxide, titanium orthoester or condensed orthoester, titanium orthoester or condensed orthoester and hydroxycarboxylic acid A reaction product comprising an ortho ester or condensed ortho ester of titanium, a hydroxycarboxylic acid and a phosphorus compound, an ortho ester of titanium or a condensed ortho ester and at least Polyhydric alcohols having a number of hydroxyl groups, 2-hydroxycarboxylic acid, or a reaction product comprising a base and the like.

  Further, for the purpose of improving the heat resistance of the copolymerized aromatic polyester finally produced by the polycondensation reaction, a phosphorus compound may be added as a stabilizer when the first reaction step is completed. When a phosphorus compound is used as a stabilizer, it is preferably used in the range of 5 to 150 ppm, further 10 to 100 ppm, and further 15 to 50 ppm based on the weight of the copolymerized aromatic polyester. The amount of the titanium compound and the phosphorus compound is such that the molar ratio (P / Ti) of the respective element amounts (phosphorus: P, titanium: Ti) is 2 or less, and further 1.5 or less. It is preferable from the viewpoint of reactivity.

  The reactive organisms obtained in this way in the first reaction step are further led to a second reaction step in which they are polycondensed to give O-chlorophenol / 1,1,2,2-tetrachloroethane (weight ratio). 40/60) is a copolymerized aromatic polyester having an intrinsic viscosity of 0.4 to 1.0 when measured at 35 ° C. using a mixed solvent. Of course, solid phase polymerization treatment may be further performed as necessary.

  Furthermore, the polycondensation reaction performed in the second reaction step will be described. First, the polycondensation temperature is not less than the melting point of the polymer to be obtained, more preferably from 5 ° C higher than the melting point to 100 ° C higher than the melting point, more preferably from 20 ° C to 50 ° C higher than the melting point. The polycondensation reaction is usually preferably carried out under reduced pressure of 50 Pa or less. If it is higher than 50 Pa, the time required for the polycondensation reaction becomes long and it becomes difficult to obtain a copolymerized aromatic polyester having a high degree of polymerization.

Examples of the polycondensation catalyst include metal compounds containing at least one metal element. Specific examples of the metal element include titanium, germanium, antimony, aluminum, nickel, zinc, tin, cobalt, rhodium, iridium, zirconium, hafnium, lithium, calcium, and magnesium. More preferable metals are titanium, germanium, antimony, aluminum, tin, etc. Among them, a titanium compound is particularly preferable because it exhibits high activity in both the esterification reaction and the polycondensation reaction. In addition, as a specific titanium compound, the thing similar to what was demonstrated by the above-mentioned 1st reaction process can be mentioned.
These catalysts may be used alone or in combination. The amount of the catalyst is preferably 0.001 to 0.5 mol%, more preferably 0.005 to 0.2 mol%, based on the number of moles of the total acid component.

  Thus, the copolymerized aromatic polyester obtained by the production method of the present invention can reduce the proportion of diethylene glycol as a byproduct because the pH of the raw material A is controlled. Preferably, from the viewpoint of the effect of the present invention, the proportion of diethylene glycol produced as a by-product based on the weight of the copolymerized aromatic polyester is preferably 2% by weight or less. The lower limit is not particularly limited, but is usually about 0.4%. By setting the ratio of the diethylene glycol component to the upper limit or less, it is possible to reduce a decrease in mechanical properties due to a melting point drop and a decrease in heat resistance due to the inclusion of diethylene glycol in the polymer skeleton. Such an amount of diethylene glycol does not become excessively strict conditions by controlling the above-mentioned pH, adding potassium compounds and sodium compounds, and further setting the conditions of the first reaction step and the second reaction step in the polymerization step within the aforementioned ranges. It can be adjusted by making it.

  The copolymerized aromatic polyester obtained by the production method of the present invention is further melt-spun into fibers, melt-formed into films and sheets, and injection-molded into bottles and containers. be able to. In particular, when a film is used, a copolymerized aromatic polyester having a stable polymer melting point can be secured, so that stable film properties can be secured and a uniform film can be produced. Moreover, since the copolymerized aromatic polyester of the present invention is copolymerized with a 6,6 ′-(alkylenedioxy) di-2-naphthoic acid component as described above, it has a low temperature expansion coefficient and humidity expansion coefficient. And has excellent dimensional stability.

  By the way, in the manufacturing method of this invention, in the range which does not impair the effect of this invention, other copolymerization components are added to the obtained copolymer aromatic polyester, for example, 10 mol% or less with respect to the number of moles of a repeating unit, and also 5 The copolymer may further be copolymerized within a range of not more than mol%. Specific examples of further copolymerization components include aliphatic dicarboxylic acid components (hexahydroterephthalic acid component, alicyclic dicarboxylic acid components such as hexahydroisophthalic acid component, succinic acid component, glutaric acid component, adipic acid component, pimelic acid Component, suberic acid component, azelaic acid component, sebacic acid component, undecadicarboxylic acid component, dodecadicarboxylic acid component, etc.) and glycol components other than ethylene glycol (isopropylene glycol component, tetramethylene glycol component, hexamethylene glycol component, octane) Methylene glycol component), hydroxycarboxylic acid component (p-hydroxybenzoic acid component, p-β-hydroxyethoxybenzoic acid component, etc.), monofunctional component (alkoxycarboxylic acid component, stearyl alcohol component, benzyl alcohol component) , Stearic acid component, behenic acid component, benzoic acid component, t-butyl benzoic acid component, benzoylbenzoic acid component, etc.), trifunctional or higher functional components (tricarballylic acid component, trimellitic acid component, trimesic acid component, pyromellitic acid component) Component, naphthalenetetracarboxylic acid component, trimethylolethane component, trimethylolpropane component, glycerol component, pentaerythritol component, etc.). In addition, it will be easily understood that the effects of the present invention can be obtained when diethylene glycol is copolymerized in that a composition close to the designed composition is obtained.

  In addition, the copolymerized aromatic polyester obtained by the production method of the present invention is not limited to the effects of the present invention, other thermoplastic polymers, stabilizers such as ultraviolet absorbers, antioxidants, plasticizers, lubricants, Flame retardants, mold release agents, pigments, nucleating agents, fillers or glass fibers, carbon fibers, layered silicates, etc. may be blended as necessary to make polyester compositions, and such polyester compositions are made. Is preferable because it is easy to impart further characteristics to the obtained molded product. Other thermoplastic polymers include polyamide resins, polycarbonates, ABS resins, polymethyl methacrylate, polyamide elastomers, polyester elastomers, and 6,6 '-(alkylenedioxy) di-2-naphthoic acid. Examples thereof include polyester-based resins whose copolymerization amount is off.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the present invention, the characteristics are measured and evaluated by the following method. Unless otherwise specified, ppm and parts are values based on weight.

(1) Intrinsic viscosity (IV)
The intrinsic viscosity of the obtained polyester was determined by measuring at a temperature of 35 ° C. using a mixed solvent of O-chlorophenol / 1,1,2,2-tetrachloroethane (40/60 weight ratio).

(2) Glass transition point and melting point The glass transition point and melting point of the obtained polyester were measured by DSC (manufactured by TA Instruments, trade name: DSC2020) at a heating rate of 10 ° C / min.

(3) Measurement of pH The pH of the raw material A in the water slurry was obtained by slurrying the raw material A with ultrapure water (ion-exchanged water) at 20% by weight and dispersing for 20 minutes with a mixer used for cooking at home. After cooling, the aqueous solution from which the powder component has been removed with analytical filter paper NO5C (manufactured by ADVANTEC) is measured by a conventional method using a pH meter.

(4) Measurement of amount of sulfuric acid, chlorine and bromine ions in the slurry Measure the amount of sulfuric acid, chlorine and bromine ions in the slurry of the water treated with water slurry of (3) with an ion chromatography analyzer (column: IonPacASII-HC). did.

(5) Amounts of potassium and sodium elements Concerning the amounts of alkali metal elements contained, the obtained polyester sample was incinerated, dissolved in 0.5N hydrochloric acid, and analyzed by an atomic absorption analyzer (HITACHI Z-2300). It was measured.

(6) DEG analysis 1 g of a polymer sample obtained by pulverizing the copolymerized aromatic polyester to 425 μm pass was prepared, added to 10 ml of hydrazine monohydrate (reagent), and hydrolyzed by heating under reflux for 2 hours. Then it was allowed to cool. Thereafter, the supernatant was analyzed by gas chromatography (Hewlett Packard 6990), and the amount of liberated diethylene glycol was measured.

[Reference Example 1]
A 10 liter autoclave with stirring was charged with 1000 parts by weight of 2-hydroxy-6-naphthoic acid, 597 parts by weight of potassium hydroxide, 263 parts by weight of dichloroethane, and 5000 parts by weight of water. The reaction was performed at 120 ° C to 130 ° C. After the reaction, the mixture was cooled and filtered to obtain a solid mainly composed of 6,6 ′-(ethylenedioxy) di-2-naphthoic acid monopotassium salt. The dry weight of this product was 380 parts by weight. This product was placed in a 5 L separable flask, and then 100 parts by weight of potassium hydroxide and 5400 parts by weight of water were added and heated at 100 ° C. When the salt was completely dissolved, it was filtered hot, 5400 parts by weight of ethanol was added, sulfuric acid was added, and acid precipitation was carried out at a temperature of 75 ° C. After acid precipitation, the precipitated solid was filtered, washed with water and dried under reduced pressure to produce 6,6- (ethylenedioxy) -di-2-naphthoic acid powder 1. The pH when the obtained powder 1 was 20 wt% water slurry was 5.0.

[Reference Example 2]
A 10 liter autoclave with stirring was charged with 1000 parts by weight of 2-hydroxy-6-naphthoic acid, 597 parts by weight of potassium hydroxide, 263 parts by weight of dichloroethane, and 5000 parts by weight of water. The reaction was carried out at a temperature between 130C. After the reaction, the mixture was cooled and filtered to obtain a solid mainly composed of 6,6 ′-(ethylenedioxy) di-2-naphthoic acid monopotassium salt. The dry weight of this product was 380 parts by weight. This product was put into a 5 L separable flask, and then 50 parts by weight of potassium hydroxide and 5400 parts by weight of water were added and heated at 100 ° C. When the salt was completely dissolved, it was filtered hot and 5400 parts by weight of ethanol was added. Then, sulfuric acid was added and acid precipitation was carried out at a temperature of 75 ° C. After acid precipitation, the precipitated solid was filtered, washed with water, and dried under reduced pressure to produce 6,6- (ethylenedioxy) -di-2-naphthoic acid powder 2. The pH when the obtained powder 2 was made into a 20 wt% water slurry was 4.1. Further, filtration and washing with water were repeated and dried under reduced pressure to produce 6,6- (ethylenedioxy) -di-2-naphthoic acid powder 3. The pH when the obtained powder 3 was made into a 20 wt% water slurry was 4.9.

[Reference Example 3]
A 10 liter autoclave with stirring was charged with 1000 parts by weight of 2-hydroxy-6-naphthoic acid, 597 parts by weight of potassium hydroxide, 280 parts by weight of dichloroethane, and 5000 parts by weight of water. The reaction was carried out at a temperature between 130C. After the reaction, the mixture was cooled and filtered to obtain a solid mainly composed of 6,6 ′-(ethylenedioxy) di-2-naphthoic acid monopotassium salt. The dry weight of this product was 380 parts by weight. This product was put into a 5 L separable flask, and then 50 parts by weight of potassium hydroxide and 5400 parts by weight of water were added and heated at 100 ° C. When the salt was completely dissolved, it was filtered hot and 5400 parts by weight of ethanol was added. Then, sulfuric acid was added and acid precipitation was carried out at a temperature of 75 ° C. After acid precipitation, the precipitated solid was filtered, washed with water, and dried under reduced pressure to produce 6,6- (ethylenedioxy) -di-2-naphthoic acid powder 4. The pH when the obtained powder 4 was 20 wt% water slurry was 3.8. Further, filtration and washing with water were repeated and dried under reduced pressure to produce 6,6- (ethylenedioxy) -di-2-naphthoic acid powder 5. The pH when the obtained powder 5 was made into a 20 wt% water slurry was 5.1.

[Reference Example 4]
6,6 ′-(alkylenedioxy) di-2-naphthoic acid synthesized by the method of Reference Example 2 2200 parts by weight, methanol 14000 parts by weight, tetra-n-butyl titanate 0.14 parts by weight as titanium element was added. And 6 hours of reaction at 220 ° C. and 5.5 MPa in an autoclave to synthesize 6,6 ′-(alkylenedioxy) di-2-naphthoic acid dimethyl ester and recrystallize it to obtain powder 6 Manufactured. The pH when the obtained powder 6 was made into a 20 wt% water slurry was 6.9.

[Example 1]
30 kg (74.6 mol) of the powder 1 (6,6 ′-(ethylenedioxy) di-2-naphthoic acid) obtained in Reference Example 1 and 7.8 kg of 2,6-naphthalenedicarboxylic acid dimethyl ester ( 32.0 mol) and 25 kg of ethylene glycol were charged into a pressure vessel equipped with a stirrer, a rectifying column and a cooling tube, and the temperature was raised to 150 ° C. At that time, 2.3 g equivalent of titanium trimellitic acid as titanium element was added, the whole reactor was pressurized to 0.25 MPa with nitrogen, and the pressure vessel internal temperature was raised to 240 ° C. The pressure was always controlled to 0.25 MPa, and the total reflux was reached when the top temperature of the rectifying column reached 200 ° C., and the reaction was continued at a reflux ratio of 1 below 200 ° C. As the reaction progressed, the inside of the container gradually became transparent, and finally the internal temperature was raised to 250 ° C. After confirming that the liquid was transparent, the reaction was completed.

Subsequently, the pressure was returned to normal pressure, 9.0 g of trimethyl phosphate was added, the internal temperature was raised again to 250 ° C., and excess ethylene glycol was distilled off. Then, the reaction solution was passed through a 30 μm wire mesh filter and the reaction solution was Transferred to a condensation vessel.
Thereafter, while gradually raising the temperature inside the reaction vessel, the inside of the vessel was slowly depressurized and the polycondensation reaction was continued until a predetermined stirring power was reached at 290 ° C. and 50 Pa to produce a copolymerized aromatic polyester.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Comparative Example 1]
Instead of the powder 1 obtained in Reference Example 1, 30 kg (74.6 mol) of the powder 2 (6,6 ′-(ethylenedioxy) di-2-naphthoic acid) obtained in Reference Example 2 was used. The same operation as in Example 1 was repeated except that it was used.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Example 2]
Instead of the powder 1 obtained in Reference Example 1, 30 kg (74.6 mol) of the powder 3 (6,6 ′-(ethylenedioxy) di-2-naphthoic acid) obtained in Reference Example 2 was used. The same operation as in Example 1 was repeated except that it was used.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Example 3]
Powder 5 (6,6 ′-(ethylenedioxy) di-2-naphthoic acid) obtained in Reference Example 3 22.91 kg (57.0 mol), dimethyl terephthalate 8.35 kg (43.0 mol), 19.5 Kg of ethylene glycol was charged into a pressure vessel equipped with a stirrer, a rectifying column, and a cooling tube, and the temperature was raised to 150 ° C. At that time, 1.44 g equivalent amount of titanium trimellitic acid as titanium element was added, the whole reactor was pressurized to 0.25 MPa with nitrogen, and the pressure vessel internal temperature was raised to 240 ° C. The pressure was always controlled to 0.25 MPa, and the total reflux was reached when the top temperature of the rectifying column reached 200 ° C., and the reaction was continued at a reflux ratio of 1 below 200 ° C. As the reaction progressed, the inside of the container gradually became transparent, and finally the internal temperature was raised to 250 ° C. After confirming that the liquid was transparent, the reaction was completed.

Subsequently, the pressure was returned to normal pressure, 5.6 g of trimethyl phosphate was added, the internal temperature was raised again to 250 ° C., and excess ethylene glycol was distilled off. Then, the reaction solution was passed through a 30 μm wire mesh filter and the reaction solution was Transferred to a condensation vessel.
Thereafter, while gradually raising the temperature inside the reaction vessel, the inside of the vessel was slowly depressurized and the polycondensation reaction was continued until a predetermined stirring power was reached at 290 ° C. and 50 Pa to produce a copolymerized aromatic polyester.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Comparative Example 2]
The same operation as in Example 3 was repeated except that the powder 4 obtained in Reference Example 3 was used instead of the powder 5 obtained in Reference Example 3.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Example 4]
Powder 1 (6,6 '-(ethylenedioxy) di-2-naphthoic acid) 15.0 kg (37.3 mol) obtained in Reference Example 1, 2,6-naphthalenedicarboxylic acid dimethyl ester 15.6 kg (64.0 mol) and 17.2 kg of ethylene glycol were charged into a pressure vessel equipped with a stirrer, a rectifying column and a cooling tube, and the temperature was raised to 150 ° C. At that time, an amount equivalent to 1.5 g of titanium trimellitic acid as a titanium element was added, the whole reactor was pressurized to 0.25 MPa with nitrogen, and the pressure vessel internal temperature was raised to 240 ° C. The pressure was always controlled to 0.25 MPa, and the total reflux was reached when the top temperature of the rectifying column reached 200 ° C., and the reaction was continued at a reflux ratio of 1 below 200 ° C. As the reaction progressed, the inside of the container gradually became transparent, and finally the internal temperature was raised to 250 ° C. After confirming that the liquid was transparent, the reaction was completed.

Subsequently, the pressure was returned to normal pressure, 5.7 g of trimethyl phosphate was added, the internal temperature was raised again to 250 ° C., and excess ethylene glycol was distilled off, and then the reaction solution was passed through a 30 μm wire mesh filter. Transferred to a condensation vessel.
Thereafter, while gradually raising the temperature inside the reaction vessel, the inside of the vessel was slowly depressurized and the polycondensation reaction was continued until a predetermined stirring power was reached at 290 ° C. and 50 Pa to produce a copolymerized aromatic polyester.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Comparative Example 3]
The same operation as in Example 4 was repeated except that the powder 2 obtained in Reference Example 2 was used instead of the powder 1 obtained in Reference Example 1.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

[Example 5]
Powder 6 (6,6 ′-(ethylenedioxy) di-2-naphthoic acid dimethyl ester) 32.1 kg (74.6 mol) obtained in Reference Example 4, 2,6-naphthalenedicarboxylic acid dimethyl ester 7 .8 kg (32.0 mol), ethylene glycol 25 kg, and trimellitic acid titanium equivalent to 1.5 g as titanium element, charged in a pressure vessel equipped with a stirrer, rectifying tower, and cooling tube The reaction was continued at a reflux ratio of 1 at a tower top temperature of 80 ° C. and a total reflux. As the reaction progresses, the inside of the vessel gradually becomes transparent. After confirming that the distillation of methanol has ended and the tower top temperature has dropped below the boiling point of methanol, the temperature is raised to 240 ° C., and the liquid in the vessel is clear. It was finally confirmed that there was.

Subsequently, 4.5 g of trimethyl phosphate was added, the internal temperature was raised again to 250 ° C., and after excess ethylene glycol was distilled off, the reaction solution was transferred to a polycondensation vessel through a 30 μm wire mesh filter. .
Thereafter, while gradually raising the temperature inside the reaction vessel, the inside of the vessel was slowly depressurized and the polycondensation reaction was continued until a predetermined stirring power was reached at 290 ° C. and 50 Pa to produce a copolymerized aromatic polyester.
The properties of the obtained copolymer aromatic polyester are shown in Table 1.

In Table 1, ENA is 6,6 ′-(ethylenedioxy) -2-naphthoic acid component, NDA is 2,6-naphthalenedicarboxylic acid component, TA is terephthalic acid component, and ENA powder characteristics are 6,6 ′. Characteristics when-(ethylenedioxy) -2-naphthoic acid component powder is made into a 20 wt% water slurry, IV means intrinsic viscosity, and DEG means diethylene glycol component amount. Further, the total anion represents the total of sulfate ions (SO4 ²⁻ ), chlorine ions, and bromine ions, and K + Na represents the total amount of potassium and sodium elements in the resin.

  The copolymerized aromatic polyester of the present invention can be subjected to ordinary melt molding such as extrusion molding, injection molding, compression molding and blow molding, and processed into fibers, films, three-dimensional molded articles, containers, hoses, etc. Can do.

Claims (5)

As an acid component, 6,6 ′-(alkylenedioxy) di-2-naphthoic acid represented by the following formula (I) or an ester-forming derivative thereof, 5 to 80 mol%, and an aromatic represented by the following formula (II) A process for producing a copolymerized aromatic polyester comprising reacting 20 to 95 mol% of a dicarboxylic acid or an ester-forming derivative thereof with ethylene glycol as a glycol component,
6,6 ′-(alkylenedioxy) di-2-naphthoic acid or an ester-forming derivative thereof having a pH in the range of 4.5 to 7.5 when 20% by weight in water slurry is used A process for producing a copolymerized aromatic polyester.

(R ¹ in the above formula (I) is an alkyl group having 1 to 10 carbon atoms, and R ² in the above formula (II) is a phenylene group or a naphthalenediyl group.)   When 6,6 ′-(alkylenedioxy) di-2-naphthoic acid or its ester-forming derivative was slurried in water of 20% by weight, the sum of sulfuric acid, chlorine and bromine ions in the slurry was the weight of the slurry. The method for producing a copolymerized aromatic polyester according to claim 1, wherein the content is 15 ppm or less based on the above.   The aromatic dicarboxylic acid represented by the formula (II) or an ester-forming derivative thereof comprises terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and ester-forming derivatives thereof. The method for producing a copolymerized aromatic polyester according to claim 1, wherein the method is at least one selected from the group.   The method for producing a copolymerized aromatic polyester according to claim 1, wherein the adjusting means for adjusting the pH of the water slurry to 4.5 to 7.5 is washing with water.   The method for producing a copolymerized aromatic polyester according to claim 1, wherein the content of the sodium and potassium elements is in the range of 1 to 200 ppm based on the weight of the copolymerized aromatic polyester obtained.