JPH07309937A - Production of polyester - Google Patents

Abstract

PURPOSE:To easily obtain lowly colored polyester by adding a specific stabilizer to the reaction system for reacting a dialkyl ester of a dicarboxylic acid with a polycarbonate or an arom. dialkyl dicarbonate in the presence of a catalyst. CONSTITUTION:A polyester is produced by adding a stabilizer to the reaction system for reacting a dialkyl ester (A) of a dicarboxylic acid with a polycarbonate and/or an arom. dialkyl dicarbonate (B) in the presence of an esterification or transesterification catalyst. Dimethyl terephthalate, etc., is esp. pref. as component A terms of cost and dimethyl carbonate of bisphenol A is esp. pref. as component B in terms of the balance between cost and physical properties. A pref. catalyst is a titanium compd. and pref. stabilizer are phosphorus-based, phenol-based, and epoxy-based stabilizer, an esp pref. one being tris(2,4-di-t- butylphenyl) phosphite. Pref. 0.00001-1 pts.wt. stabilizer is used based on 100 pts.wt. polyester produced, and the reaction is conducted pref. in two stage at different temps.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing polyester. More specifically, it relates to a method for producing a low-colored polyester, which comprises adding a specific stabilizer when a polyester is produced by reacting a dialkyl ester of dicarboxylic acid with a polycarbonate and / or an aromatic dialkyl dicarbonate.

[0002]

2. Description of the Related Art Various methods for producing thermoplastic polyesters are known, but the most general method is a melt polycondensation reaction of a dicarboxylic acid and a diol in the presence of a catalyst. However, although the method is effective for producing a polyester using an aliphatic diol represented by ethylene glycol or the like as a diol, 2,2'-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A is described. In the production of polyester using an aromatic diol represented by
Aromatic diols have poor reactivity, and when a polyester having a high degree of polymerization is to be obtained, a reaction under severe conditions is required, resulting in a problem that the resulting polymer is severely colored.

In order to avoid such problems, JP-A-5-262864 discloses a method for producing an aromatic polyester in which a dialkyl ester of an aromatic dicarboxylic acid is reacted with an aromatic polycarbonate and / or an aromatic dialkyl dicarbonate. Is described. However, although the reaction conditions are mild in this method, there is a problem that the polyester after the polycondensation is severely colored when using the exemplified Ti or Zr-based catalyst. Recently, it has been revealed that Sn or Zn-based catalysts have some effect on the reduction of coloration as compared with Ti-based catalysts in the production of the above-mentioned aromatic polyester, but especially in the field where transparency is required. Had a problem that the reduction effect was not yet sufficient.

[0004]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the conventional methods for producing polyesters,
The purpose of the present invention is to provide a new method for producing a low-colored polyester.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, in the polymerization of a dialkyl ester of an aromatic dicarboxylic acid and an aromatic polycarbonate and / or an aromatic dialkyl carbonate, By adding a specific stabilizer at an arbitrary point during polymerization, it is possible to produce a polyester having a greatly reduced coloration, and it has been found that the above object can be achieved, and the present invention has been completed.

That is, in the present invention, a stabilizer is added when a polyester is produced by reacting a dialkyl ester of a dicarboxylic acid with a polycarbonate and / or an aromatic dialkyl dicarbonate in the presence of an esterification or transesterification catalyst. A method for producing a low-colored polyester characterized by the above.

The present invention will be described in detail below. In the present invention, examples of the polycarbonate used as a raw material include compounds represented by the general formula (I).

[0008]

[Chemical 4]

[In the general formula (I), R ¹ is a divalent aromatic hydrocarbon group, R ² —X—R ³ group (provided that R ² and R ³ are 2
It is a valent aromatic hydrocarbon group, and X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And a represents a positive integer. However, R ¹ is not limited to one type and may be a copolymer of two or more types. As the polycarbonate used in the present invention, a polycarbonate based on bisphenol A is particularly preferable from the viewpoint of balance between physical properties and cost.

As the aromatic dialkyl dicarbonate used in the present invention, compounds represented by the general formula (II) can be mentioned.

[0011]

[Chemical 5]

[R ⁴ in the general formula (II) is a divalent aromatic hydrocarbon group, R ⁶ -X-R ⁷ group (provided that R ⁶ and R ⁷ are 2
It is a valent aromatic hydrocarbon group, and X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And R ⁵ has 1 to 4 carbon atoms.
Is an aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

Specific examples of such compounds include the following aromatic diols dimethyl, diethyl and diphenyl carbonate. That is, as specific examples of the aromatic diol, for example, bisphenol A, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4
-Hydroxy-3,5-dichlorophenyl) methane,
1,1-bis (4-hydroxyphenyl) cyclohexylmethane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-
Phenylethane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 4,
4'-dihydroxydiphenyl ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxy-3,5-dimethylphenyl) sulfone, 4,
4'-dihydroxybenzophenone, 2,2-bis (4
-Hydroxy-3,5-dimethylphenyl) propane,
Tetrabromobisphenol A, tetrachlorobisphenol A, dihydroxydiphenyl, hydroquinone,
Examples thereof include resorcinol, dihydroxynaphthalene, dihydroxyanthracene, phenolphthalein, ferulescein, 2,2′-dihydroxy-1,1-dinaphthylmethane, 4,4′-dihydroxydinaphthyl and the like. Of these, bisphenol A is easily available.
Particularly preferred is dimethyl carbonate. In the present invention, the above-mentioned polycarbonate and aromatic dialkyl dicarbonate may be used alone or in combination of two or more kinds, or may be used in combination of one kind or two or more kinds.

In the present invention, the dialkyl ester of dicarboxylic acid used as another raw material is
The compound represented by general formula (III) can be mentioned.

[0015]

[Chemical 6]

[R ⁸ in the general formula (III) has 6 to 1 carbon atoms.
A divalent aromatic hydrocarbon group of 0 (provided that the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like), and a carbon number of 2 to 2.
0 represents an aliphatic or alicyclic hydrocarbon group, and R ⁹ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. ]

Specific examples of the dialkyl ester of dicarboxylic acid include dimethyl, diethyl and diphenyl esters of dicarboxylic acid shown below. That is, specific examples of the dicarboxylic acid include terephthalic acid, methoxyterephthalic acid, ethoxyterephthalic acid, fluoroterephthalic acid, chloroterephthalic acid, methylterephthalic acid, isophthalic acid, phthalic acid, methoxyisophthalic acid, diphenylmethane-4,4'-. Dicarboxylic acid, diphenylmethane-3,3'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl-4,
4'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-
2,6-dicarboxylic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, dodecanedicarboxylic acid, 3-methylazelaic acid, glutaric acid, succinic acid, cyclohexane-1,4-dicarboxylic acid, cyclohexane-1,3
-Dicarboxylic acid, cyclopentane-1,3-dicarboxylic acid and the like. These may be used alone or in combination of two or more. Among these,
From the viewpoint of physical properties and cost, terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexane-
It is particularly preferable to use dimethyl esters of 1,4-dicarboxylic acid and cyclohexane-1,3-dicarboxylic acid alone or in combination of two or more kinds.

The method for producing a polyester of the present invention is characterized by reacting a polycarbonate and / or an aromatic dialkyl dicarbonate with a dialkyl ester of a dicarboxylic acid in the presence of a catalyst. As the catalyst used in this reaction, generally known esterification and transesterification catalysts can be used. As these catalysts,
Titanium compound, tin compound, antimony compound, cobalt compound, zirconium compound, magnesium compound,
Examples thereof include a manganese compound, a germanium compound, an aluminum compound, a zinc compound, a calcium compound, a lithium compound, a sodium compound and a potassium compound. Among these, titanium compounds, tin compounds, antimony compounds, zirconium compounds, and zinc compounds are preferable from the viewpoint of reaction activity.

Specific examples of such compounds include tetra-
n-butoxy titanium, tetraethoxy titanium, tetra-
n-butoxyzirconium, tin dichloride, tin acetate, tin tetrachloride, tin tetrabromide, trichlorobutyltin, dichlorodibutyltin, dibutyltin oxide, diphenyltin oxide, dioctyltin oxide, butylhydroxytin oxide,
Dibutyltin diacetate, triethoxyantimony, tributoxyantimony, antimony trioxide, zinc chloride, zinc bromide, zinc iodide, zinc acetate, zinc carbonate and the like are preferable.
Further, from the viewpoint of low coloration, alkali metal compounds, particularly lithium compounds are preferable. Specific examples of such a lithium-based catalyst include lithium, lithium hydroxide, lithium hydride, lithium aluminum hydride, lithium acetate, and lithium salts such as phenol, bisphenol A, benzoic acid, terephthalic acid, and isophthalic acid. The amount of these catalysts used is not particularly limited,
Polyester 100 produced from the balance of reactivity and physical properties
0.0001 to 1 part by weight, preferably 0.
0005-0.1 parts by weight are used.

As the stabilizer used in the present invention, a specific one of the generally known stabilizers for producing polyesters is used. Specific examples of these stabilizers include phosphorus-based compounds, phenol-based compounds, thioether-based compounds, amine-based compounds, benzotriazole-based compounds and epoxy-based compounds, which may be used alone or in combination of two or more. Used. Examples of the phosphorus-based compound include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid, phosphoric acid ester and phosphorous acid ester, which may be used alone or in combination of two or more kinds.

Examples of the phosphoric acid ester include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tridodecyl phosphate, trioctadecyl phosphate, dioctadecyl pentaerythrityl diphosphate, tris (2-chloroethyl) phosphate, tris ( A few
-Trichlorophosphate such as dichloropropyl) phosphate, tricycloalkylphosphate such as tricyclohexylphosphate, triphenylphosphate, tricresylphosphate, triarylphosphate such as tris (nonylphenyl) phosphate, 2-ethylphenyldiphenylphosphate, etc. Named
These are used alone or in combination of two or more.

Examples of the phosphite include trimethylphosphite, triethylphosphite, tributylphosphite, trioctylphosphite, tris (2-ethylhexyl) phosphite, trinonylphosphite, tridodecylphosphite, trioctadecyl. Phosphite, didodecyl pentaerythrityl diphosphite, tris (2-chloroethyl) phosphite,
Trialkylphosphites such as tris (2,3-dichloropropyl) phosphite, tricycloalkylphosphites such as tricyclohexylphosphite, triphenylphosphite, tricresylphosphite, tris (ethylphenyl) phosphite, tris Triaryl phosphites such as (nonylphenyl) phosphite, tris (hydroxyphenyl) phosphite, tris (4-t-butylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, phenyl Didecyl phosphite, diphenyl decyl phosphite,
Arylalkyl phosphites such as diphenylisooctylphosphite, phenyldiisooctylphosphite, 2-ethylhexyldiphenylphosphite, diphenylnonylphenylphosphite, dioctadecylpentaerythrityldiphosphite, bis (2,4-di-
t-butylphenyl) pentaerythrityl diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythrityl diphosphite and the like,
These are used alone or in combination of two or more. Among the phosphorus compounds, phosphite ester is preferable,
Among them, aromatic phosphite is preferable, and tris (2,4-di-t-butylphenyl) phosphite is particularly preferable.

Examples of the phenol compound include pentaerythrityl-tetrakis [3- (3,5-di-t-].
Butyl-4-hydroxyphenyl) propionate],
1,1,3-tris (2-methyl-4-hydroxy-5)
-T-butylphenyl) butane, 1,1-bis (2-methyl-4-hydroxy-5-t-butylphenyl) butane, tris- (3,5-di-t-butyl-4-hydroxybenzyl)- Isocyanurate, distearyl (4-
Hydroxy-3-methyl-5-t-butyl) benzyl malonate, 1,6-hexanediol-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], 2,2-thio-diethylenebis [3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,3 5-di-t-butyl-4-hydroxybenzyl) benzene, 4-hydroxymethyl-2,6-di-t-butylphenol and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Of these, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is particularly preferable.

Examples of thioether compounds include:
Didodecyl-thiodipropionate, ditridecyl-thiodipropionate, dimyristyl-thiodipropionate, dioctadecyl-thiodipropionate, pentaerythrityl-tetrakis [3- (n-dodecylthio)
Propionate] and the like, which are used alone or in combination of two or more kinds. Of these, pentaerythrityl-tetrakis [3- (n-dodecylthio) propionate] and the like are particularly preferable. Examples of amine compounds include bis (2,2,6,6-tetramethyl-4
-Piperidyl) sebacate, bis (1,2,2,6,6)
-Pentamethyl-4-piperidyl) sebacate, 1-
[2- {3- (3,5-di-t-butyl-4-hydroxyphenyl) pyropionyloxy} ethyl] -4- {3
-(3,5-Di-t-butyl-4-hydroxyphenyl) pyropionyloxy} -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl- 3-octyl-1,2,3-triazaspiro-4,5-undecane-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine,
2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6)
6-pentamethyl-4-piperidyl), tetrakis (1,2,3,4-tetramethyl-4-piperidyl)-
1,2,3,4-butanetetracarboxylate and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Of these, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate is particularly preferable.

The benzotriazole-based compound is 2
-(5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α,
α-Dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxy) Phenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxy Examples thereof include phenyl) benzotriazole and 2- (2′hydroxy-5′-t-octylphenyl) benzotriazole. These may be used alone or in combination of two or more. Of these, 2- [2-hydroxy-
3,5-bis (α, α-dimethylbenzyl) phenyl]
-2H-benzotriazole is particularly preferred.

The epoxy compounds include epoxidized soybean oil, epoxidized linseed oil, phenylglycidyl ether, allylglycidyl ether, t-butylphenylglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-cyclohexanecarbochelate, 3,4
-Epoxy-6-methylcyclohexylmethyl-3,4
-Epoxy-6-methylcyclohexanecarboxylate, 2,3-epoxycyclohexylmethyl-3,4-
Epoxycyclohexanecarboxylate, 4- (3,
4-epoxy-5-methylcyclohexyl) -butyl-
3,4-epoxycyclohexanecarboxylate, 3,
4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, bisphenol A-diglycidyl ether, tetrabromobisphenol A-di Glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis (epoxyclopentadiphenyl) ether, bisepoxyethylene glycol, bis (epoxycyclohexyl) adipate, butadiene diepoxide, tetraphenylethyleneepoxide, octyl Epoxytalate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dime Le-1,2-epoxycyclohexane, 3-methyl -5-t-butyl - epoxycyclohexane, octadecyl-2,2-dimethyl-3,4-epoxycyclohexane carboxylate, n- butyl -
2,2-dimethyl-3,4-epoxycyclohexanecarboxylate, cyclohexyl-2-methyl-3,4
-Epoxycyclohexanecarboxylate, n-butyl-2-isopropyl-3,4-epoxy-5-methylhexanecarboxylate, octadecyl-3,4-epoxycyclohexanecarboxylate, 2-ethylhexyl-3 ', 4'-epoxycyclohexane Carboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3 ', 4'-epoxycyclohexanecarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3-t-butyl-4,5-epoxyanhydrotetrahydro Phthalic acid, diethyl-4,5-epoxy-cis-1,
2-cyclohexanedicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2
-Cyclohexanedicarboxylate and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Of these, bisphenol A-diglycidyl ether is particularly preferably used.

The amount of the stabilizer added depends on the amount of polyester 10 produced.
It is 0.00001 to 1 part by weight, more preferably 0.0005 to 0.05 part by weight, relative to 0 part by weight. 0.0
If the amount is less than 0001 parts by weight, the effect is not sufficient, and there is a high possibility that the formed polyester or coloring occurs during molding. on the other hand,
If the amount exceeds 1 part by weight, the effect will be saturated, the surface of the molded product will be defective, and the heat distortion resistance, rigidity, surface hardness, etc. will decrease. The stabilizer can be added at any time during the polymerization, but is preferably added at the start of the reaction. By adding it at the start of the reaction, it is possible to suppress deterioration of the produced polyester due to heat, and the addition method becomes simpler.

In the present invention, it is preferable to carry out the reaction in two steps at different temperatures. In the first step, 2
The heating is performed at 00 to 300 ° C, more preferably 250 to 300 ° C. In this step, the polycarbonate is depolymerized by a transesterification reaction to produce a dialkyl carbonate. In the second step, heating is performed at 280 to 350 ° C., more preferably 300 to 350 ° C. under reduced pressure (0.05 to 1.0 Torr). In this step, a high molecular weight polyester is obtained by removing the remaining portion of the produced dialkyl carbonate. However, the present invention is not limited to the reaction in the above two-step process, and the reaction may be carried out at multi-step temperature and reduced pressure, or may be carried out under the same temperature condition throughout the reaction. .

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto and can be appropriately modified within the scope of the invention. The properties of the polymer were measured according to the methods described below. (1) Weight-average molecular weight of polymer [Mw] Using a 510-type GPC system manufactured by Waters, chloroform was used as a mobile phase, and the concentration was measured at a column temperature of 35 ° C. and a polymer concentration of 2 mg / ml. The weight average molecular weight was calculated using polystyrene as a standard sample. (2) Glass transition temperature [Tg] of polymer It was measured using a DSC-7 differential scanning calorimeter manufactured by Perkin-Elmer under a nitrogen stream at a temperature rising rate of 20 ° C / min. (3) Yellowness Index [YI] of Polymer Using a sample obtained by pressing the obtained polymer to a thickness of 1/8 inch, using a Z-Σ80 color difference meter manufactured by Nippon Denshoku Industries,
It was measured by a transmission method based on JIS K 7013.

Example 1 Polycarbonate (manufactured by Teijin Limited, Panlite L-1
250 W, Mv = 25000) 254 g, dimethyl terephthalate 107 g (0.55 mol), dimethyl isophthalate 107 g (0.55 mol), titanium tetra-n-butyl 1.1 g (3.3 mmol), tris (2,4) -Di-t-butylphenyl) phosphite.
18 g (0.28 mmol) was charged into a 200 ml four-neck round bottom flask equipped with a stirring blade, a nitrogen inlet, a pressure reducing port, and a distillation port, and after nitrogen substitution, 280 in a nitrogen flow state.
Heated to ° C. The temperature was maintained as it was for 1 hour, and then the temperature was raised to 300 ° C. over 20 minutes. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. The distillate amount was 49.6 g (55% of theory). The pressure of the reaction system was slowly reduced (1 Torr in 30 minutes), the temperature was raised to 320 ° C., and the temperature was maintained for 1 hour. After the stirring was stopped, the reaction mixture was poured out to obtain 38.8 g of polymer. The measurement results of the polymer properties are shown in Table 1.

Example 2 Example 3 was repeated except that the catalyst was changed to 0.34 g (3.3 mmol) of lithium acetate. The measurement results of the polymer properties are shown in Table 1.

Example 3 1.2 g (3.3 mmol) of dibutyltin diacetate as a catalyst
The same procedure as in Example 1 was performed except that The measurement results of the polymer properties are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 1.

Comparative Example 2 The procedure of Example 2 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 1.

Comparative Example 3 The procedure of Example 3 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 1.

[0036]

[Table 1]

Example 4 Polycarbonate (Panlite L-1 manufactured by Teijin Limited)
250 W, Mv = 25000) 254 g, dimethyl terephthalate 64 g (0.33 mol), dimethyl isophthalate 64 g (0.33 mol), naphthalene-2,6-
Dicarboxylic acid dimethyl ester 95 g (0.44 mol), titanium tetra-n-butyl 1.1 g (3.3
And 0.18 g (0.28 mmol) of tris (2,4-di-t-butylphenyl) phosphite 200 equipped with a stirring blade, a nitrogen inlet, a pressure reducing port, and a distillation port.
The mixture was placed in a ml four-necked round bottom flask and, after purging with nitrogen, heated to 280 ° C. in a nitrogen flow state. The temperature was maintained as it was for 1 hour, and then the temperature was raised to 300 ° C. over 20 minutes. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. The distillate amount was 46.9 g (theoretical amount of 52
%)Met. Depressurize the reaction system (1 Torr in 30 minutes),
The temperature was raised to 320 ° C. and kept for 1 hour. After the stirring was stopped, the reaction mixture was poured out to obtain 35.6 g of polymer. The measurement results of the polymer properties are shown in Table 2.

Example 5 Example 4 was repeated except that the catalyst was changed to 0.34 g (3.3 mmol) of lithium acetate. The measurement results of the polymer properties are shown in Table 2.

Example 6 1.2 g (3.3 mmol) of dibutyltin diacetate as a catalyst
The same procedure as in Example 4 was performed except that The measurement results of the polymer properties are shown in Table 2.

Comparative Example 4 The procedure of Example 4 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 2.

Comparative Example 5 The procedure of Example 5 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 2.

Comparative Example 6 The procedure of Example 6 was repeated except that tris (2,4-di-t-butylphenyl) phosphite was not used. The measurement results of the polymer properties are shown in Table 2.

[0043]

[Table 2]

Example 7 Polycarbonate (manufactured by Teijin Limited, Panlite L-1
250 W, Mv = 25000) 254 g, dimethyl terephthalate 107 g (0.55 mol), dimethyl isophthalate 107 g (0.55 mol), dibutyltin diacetate 1.2 g (3.3 mmol), pentaerythrityl-
0.38 g of tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (1)
(0.28 mmol), a stirring blade, a nitrogen inlet, a pressure reducing port,
A 200 ml four-necked round bottom flask equipped with a distillation port was charged, the atmosphere was replaced with nitrogen, and the mixture was heated to 280 ° C. in a nitrogen flow state. The temperature was maintained as it was for 1 hour, and then the temperature was raised to 300 ° C. over 20 minutes. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. The amount of distillate is 4
It was 6.9 g (52% of theory). The pressure of the reaction system was reduced (1 Torr in 30 minutes), the temperature was raised to 320 ° C., and the temperature was maintained for 1 hour. After the stirring was stopped, the reaction mixture was poured out to obtain 42.6 g of polymer. The measurement results of the polymer properties are shown in Table 2.

Example 8 A stabilizer was pentaerythrityl-tetrakis [3- (n-
Dodecylthio) propionate] (2) 0.32 g
The same procedure as in Example 7 was performed except that the amount was changed to (0.28 mmol). Table 3 shows the measurement results of the polymer characteristics.

Example 9 The same as Example 7 except that the stabilizer was changed to 0.13 g (0.28 mmol) of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (3). went. Table 3 shows the measurement results of the polymer characteristics.

Example 10 As a stabilizer, 2- [2-hydroxy-3,5-bis (α, α) was used.
-Dimethylbenzyl) phenyl] -2H-benzotriazole (4) The procedure of Example 7 was repeated except that the amount was changed to 0.13 g (0.28 mmol). Table 3 shows the measurement results of the polymer characteristics.

Example 11 Example 11 was repeated except that the stabilizer was changed to 0.10 g (0.28 mmol) of bisphenol A-diglycidyl ether (5). Table 3 shows the measurement results of the polymer characteristics.

[0049]

[Table 3]

Example 12 Polycarbonate (manufactured by Teijin Ltd., Panlite L-1)
250 W, Mv = 25000) 254 g, dimethyl terephthalate 107 g (0.55 mol), dimethyl isophthalate 107 g (0.55 mol), titanium tetra-n-butyl 1.1 g (3.3 mmol), tris (2,4) -Di-t-butylphenyl) phosphite.
18 g (0.28 mmol) was charged into a 200 ml four-neck round bottom flask equipped with a stirring blade, a nitrogen inlet, a pressure reducing port, and a distillation port, and after nitrogen substitution, 320 in a nitrogen flow state.
Heated to ° C. The temperature was maintained for 1 hour. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. The amount of distillate was 52.3 g (58% of theory). The reaction system was slowly depressurized (1 Torr in 30 minutes) while maintaining the temperature at 320 ° C., and kept for 3 hours. After stopping the stirring, the reaction mixture was discharged to obtain 42.4 g of polymer. The molecular weight (weight average molecular weight) of the obtained polymer is G
The glass transition temperature (Tg) was 49000 (converted to polystyrene) by PC measurement and 191 ° C. by DSC measurement.
The yellowness index (Y.I.) of the 1/8 inch molded product of the obtained polyester was 74.

[0051]

As described above, according to the present invention,
A polyester having a low degree of coloring can be produced by a simple and inexpensive method.

Claims (18)

[Claims] 1. A stabilizer is added when a polyester is produced by reacting a dialkyl ester of a dicarboxylic acid with a polycarbonate and / or an aromatic dialkyl dicarbonate in the presence of an esterification or transesterification catalyst. The method for producing polyester. 2. The method according to claim 1, wherein the stabilizer is at least one compound selected from phosphorus compounds, phenol compounds, thioether compounds, amine compounds, benzotriazole compounds, and epoxy compounds. . 3. The phosphorus compound is tris (2,4-di-t).
The method according to claim 2, which is -butylphenyl) phosphite. 4. The phenolic compound is pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-).
Hydroxyphenyl) propionate].
The manufacturing method described. 5. The method according to claim 2, wherein the thioether compound is pentaerythrityl-tetrakis [3- (n-dodecylthio) propionate]. 6. The amine compound is bis (2,2,6,6).
-Tetramethyl-4-piperidyl) sebacate. 7. The benzotriazole compound is 2- [2
The method according to claim 2, which is -hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole. 8. The epoxy compound is bisphenol A-
The production method according to claim 2, which is diglycidyl ether. 9. The stabilizer is added in an amount of 0.00001 to 1 part by weight based on 100 parts by weight of the produced polyester.
~ 8. 10. The production method according to claim 1, wherein in the latter half of the reaction, the degree of reduced pressure is increased to carry out the reaction. 11. A polycarbonate is represented by the following general formula (I):
The manufacturing method of Claims 1-10 shown by. [Chemical 1] [R ¹ in the general formula (I) is a divalent aromatic hydrocarbon group, R 1
² -X-R ³ group (wherein, R ² and R ³ is a divalent aromatic hydrocarbon group, X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And a represents a positive integer. However, R
¹ is not limited to ^one type, and may be a copolymer of two or more types. ] 12. The method according to claim 1, wherein the aromatic dialkyl dicarbonate is represented by the following general formula (II). [Chemical 2] [R ⁴ in the general formula (II) is a divalent aromatic hydrocarbon group, R 4
⁶ -X-R ⁷ group (wherein, R ⁶ and R ⁷ is a divalent aromatic hydrocarbon group, X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And R ⁵ is an aliphatic hydrocarbon group having 1 to 4 carbon atoms. Alternatively, it represents an aromatic hydrocarbon group having 6 to 10 carbon atoms. ] 13. The production method according to claim 1, wherein the dialkyl ester of dicarboxylic acid is represented by the following general formula (III). [Chemical 3] [R ⁸ in the general formula (III) is a divalent aromatic hydrocarbon group having 6 to 10 carbon atoms (provided that the hydrogen atom of the aromatic ring is substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like). Or an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms, and R ⁹ is an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an aromatic group having 6 to 10 carbon atoms. Indicates a hydrocarbon group. ] 14. The polycarbonate has an aromatic hydrocarbon group of 2,2′-bis (4-hydroxyphenylpropane).
(Bisphenol A) residue, The manufacturing method of Claims 1-13. 15. The method according to claim 1, wherein the aromatic hydrocarbon group of the aromatic dialkyl dicarbonate is a 2,2′-bis (4-hydroxyphenylpropane) (bisphenol A) residue. 16. The method according to claim 1, wherein the dialkyl ester of dicarboxylic acid is at least one selected from dimethyl terephthalate, dimethyl isophthalate and naphthalene-2,6-dicarboxylic acid dimethyl ester. 17. An esterification or transesterification catalyst,
At least one selected from titanium-based catalysts, tin-based catalysts, antimony-based catalysts, zirconium-based catalysts and zinc-based catalysts
The method according to claim 1, which is a seed. 18. An esterification or transesterification catalyst of 0.0001 to 1 per 100 parts by weight of the produced polyester.
The manufacturing method according to claim 1, which is used in parts by weight.