JP2003147060A - Method for producing copolymerized polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a copolymerized polyester resin having excellent color tone and resistant to discoloration in molten state by copolymerizing a phenylenedioxydiacetic acid as a dicarboxylic acid component to impart gas barrierness to the polymer. SOLUTION: The copolymerized polyester resin is produced by carrying out the esterification reaction or thransesterification reaction of a dicarboxylic acid component composed mainly of terephthalic acid and containing a phenylenedioxydiacetic acid as a copolymerizing component and a diol component composed mainly of ethylene glycol and subjecting the product to polycondensation reaction in the presence of a polycondensation catalyst and a phosphorus compound. A 20-120 C organic phosphite compound is used as the phosphorous compound.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a copolyester resin, and more particularly, it is excellent in color tone when copolymerizing phenylenedioxydiacetic acids as a dicarboxylic acid component for imparting gas barrier properties. At the same time, it relates to a method for producing a copolyester resin in which coloring in a molten state is suppressed.

[0002]

2. Description of the Related Art Polyester resins represented by polyethylene terephthalate resins have hitherto been noted for their excellent transparency, gas barrier properties, safety and hygiene properties, in addition to their excellent mechanical and chemical properties. As a bottle that is stretch blow molded from an injection molded preform,
As a tray or cup formed by thermoforming an extruded sheet, or as a film obtained by biaxially stretching the sheet,
In particular, it has shown remarkable growth in the food packaging field.

However, although the gas barrier properties of polyester resins are superior to those of polyolefin resins, polystyrene resins, etc. which are widely used in the food packaging field, the barrier properties against oxygen gas, carbon dioxide gas, etc. are particularly severe. It cannot be said that the bottles of carbonated drinks, alcoholic drinks and the like required are always sufficient, and the tendency is remarkable especially in recent miniaturized bottles.

On the other hand, as a method for improving the gas barrier property of a polyethylene terephthalate resin, for example, in JP-A-60-501060 and JP-A-5-186570, phenylene dioxydiacetic acid containing terephthalic acid as a main component is disclosed. There is disclosed a method of copolymerizing a dicarboxylic acid component containing a group of compounds as a copolymerization component and a diol component containing ethylene glycol as a main component.

On the other hand, the present inventors have found that the copolyester resins obtained by copolymerizing the phenylenedioxydiacetic acids described in these publications generally prevent the deterioration of the color tone of the polyester resin and impart thermal stability. Phosphorus compounds such as orthophosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, ethyl acid phosphate, phosphorous acid, trimethyl phosphate, triethyl phosphite, triphenyl phosphite, etc. Despite the use of, a little yellowish and inferior in color tone, coloring occurs even in a molten state, for example, during melt molding, and is known to be a problem particularly as a material used in the field of food packaging, etc. The examination for the improvement has been repeated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art. Therefore, the present invention is based on the coexistence of phenylenedioxydiacetic acids as a dicarboxylic acid component in order to impart a gas barrier property. An object of the present invention is to provide a method for producing a copolyester resin which is excellent in color tone in polymerization and is suppressed from being colored in a molten state.

[0007]

Means for Solving the Problems The present inventors have completed the present invention by finding that the above object can be achieved by using a specific phosphorus compound, as a result of intensive studies to solve the above-mentioned problems. That is, according to the present invention, a dicarboxylic acid component containing terephthalic acid as a main component and a phenylenedioxydiacetic acid as a copolymerization component and a diol component containing ethylene glycol as a main component are subjected to an esterification reaction or a transesterification reaction to produce a heavy polymer. In producing a copolymerized polyester resin by polycondensing in the presence of a condensation catalyst and a phosphorus compound, a method for producing a copolymerized polyester resin using an organic phosphite compound having 20 to 120 carbon atoms as a phosphorus compound, And

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a copolyester resin of the present invention, the dicarboxylic acid component is terephthalic acid or its terephthalic acid such as an ester-forming derivative such as an alkyl (about 1 to 4 carbon atoms) ester thereof. The main component is ethylene glycol as the main component. Specific examples of the alkyl ester as an ester-forming derivative of terephthalic acid include dimethyl terephthalate and diethyl terephthalate.

In the present invention, the ethylene terephthalate unit composed of terephthalic acids as the dicarboxylic acid component and ethylene glycol as the diol component preferably accounts for 80 mol% or more of the constitutional repeating units, and 90 mol% or more. Is more preferable. When the ethylene terephthalate unit is less than the above range, the mechanical properties and heat resistance of the copolyester resin tend to be poor.

In the present invention, phenylenedioxydiacetic acids are essential as a copolymerization component in the dicarboxylic acid component, and the phenylenedioxydiacetic acids account for 0.1 to 0.1% of the total dicarboxylic acid components. It is preferably 20 mol%, more preferably 0.2 to 10 mol%, and particularly preferably 0.5 to 5 mol%. When the ratio of the phenylenedioxydiacetic acids to the total dicarboxylic acid components is less than the above range, it tends to be difficult to impart gas barrier properties to the copolyester resin, while when the above range is exceeded, during esterification or transesterification. The reaction rate of is decreased and the polymerizability tends to be poor.

Specific examples of the phenylenedioxydiacetic acids include 1,2-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, and the like.
1,4-phenylenedioxydiacetic acid, 2-methyl-1,
3-phenylenedioxydiacetic acid, 5-methyl-1,3-
Phenylenedioxydiacetic acid, 6-methyl-1,3-phenylenedioxydiacetic acid, 5-ethyl-1,3-phenylenedioxydiacetic acid, 6-ethyl-1,3-phenylenedioxydiacetic acid, 5- Examples include methoxy-1,3-phenylenedioxydiacetic acid, 6-methoxy-1,3-phenylenedioxydiacetic acid, 4-chloro-1,3-phenylenedioxydiacetic acid, and ester-forming derivatives thereof. Of these, 1,3-phenylenedioxydiacetic acid and its ester-forming derivatives are preferred.

As dicarboxylic acid components other than terephthalic acid and phenylenedioxydiacetic acid, for example,
Phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, 4,4 '
-Aromatic dicarboxylic acids such as diphenyl sulfone dicarboxylic acid and 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacine One or more of an acid, an aliphatic dicarboxylic acid such as diglycolic acid, or an ester-forming derivative thereof, and as a diol component other than ethylene glycol, for example, propylene glycol, trimethylene glycol, tetramethylene glycol, penta Aliphatic diols such as methylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol, 1,2-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,
A cycloaliphatic diol such as 4-cyclohexanedimethylol,
Pyrocatechol, resorcinol, hydroquinone,
4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane,
Bis (4-hydroxyphenyl) sulfone, bis (4-
One or more aromatic diols such as β-hydroxyethoxyphenyl) sulfonic acid, and further hydroxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, and alkoxycarboxylic acids. Acids, monofunctional components such as stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, Glycerol,
One or two or more trifunctional or higher polyfunctional components such as pentaerythritol may be used as the copolymerization component. Among them, the dicarboxylic acid component is isophthalic acid and the diol component is diethylene glycol. ,
1,4-Cyclohexane dimethylol and the like are preferable.
These are used within the range of preferably 10 mol% or less, more preferably 5 mol% or less, based on the total dicarboxylic acid component and the total diol component.

The method for producing a copolyester resin of the present invention comprises the steps of adding the dicarboxylic acid component and the diol component
In the polycondensation in the presence of a polycondensation catalyst and a phosphorus compound through an esterification reaction or a transesterification reaction, it is essential to use an organic phosphite compound having 20 to 120 carbon atoms as the phosphorus compound. If the organic phosphite compound is not used, it will be difficult to achieve the object of the present invention.

In the present invention, the organic phosphite compound having 20 to 120 carbon atoms is not particularly limited as long as the carbon number satisfies this range, but the following general formulas (I) and (II) , And any compound selected from the group consisting of the compounds represented by (III).

[0015]

[Chemical 2]

[R in Formula (I)¹And R²R in formula (II)³
And R^Four, And R in formula (III)^FiveAnd R ⁶Are each independent
An aliphatic group, an alicyclic group, or an aromatic group is represented by the formula (II)
X in the formula is a divalent or trivalent aliphatic group, an alicyclic group, or an aromatic group.
It represents an aromatic group, and n is 1 or 2. ]

Where R in formulas (I), (II) and (III)
The aliphatic groups represented by ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ may have a substituent, for example, have 1 carbon atoms.
The linear or branched alkyl group having about 20 to 20 may have a substituent as the alicyclic group. For example, a cycloalkyl group having about 5 to 10 carbon atoms is an aromatic group. May have a substituent, for example, a phenyl group, a naphthyl group, and the like. Examples of the substituent include a linear or branched alkyl group having about 1 to 20 carbon atoms. Group, phenyl group and the like.

The aliphatic group represented by X in the formula (II) may have a substituent, for example, an alkylene group having about 1 to 10 carbon atoms, an alkanthryl group and the like are alicyclic groups. The formula group may have a substituent, for example, a cycloalkylene group having about 5 to 10 carbon atoms, a cycloalkanthryl group, or the like, and the aromatic group may have a substituent. Good examples include, for example, a phenylene group, a naphthylene group, a benzenetolyl group and the like.

The above general formulas (I), (II), and (III)
Specific examples of the organic phosphite compound represented by
Is, for example, represented by the general formula (I):
(Diphenyl) octyl phosphite (C₂₀H₂₇O
₃P), (diphenyl) decyl phosphite (C_{twenty two}H₃₁
O₃P), tridecyl phosphite (C₃₀H₆₃O
₃P), bis [2,4-bis (1,1-dimethylethyl)
) -6-Methylphenyl] ethyl phosphite (C₃₂
H₅₁O₃P), tris (2,4-di-t-butylphenyl)
Le) Phosphite (C₄₂H_{twenty one}O₃P), Tris (nonyl)
Phenyl) phosphite (C ₄₂H_{twenty one}O₃P), bis (di)
Nonylphenyl) nonylphenyl phosphite (C₅₄H
₈₇O₃P) and the like are also represented by the general formula (II).
Then, tetraalkyl (C₉~₁₂) [2,2-bis
(Diphenyl) propane] diphosphite (C₆₃~₇₅H
₁₁₄~₁₃₈O₆P₂), Tetratridecyl [1,1-bi
Sus (2-methyl-5-t-butylphenyl) -n-butane
Diphosphite (C₇₈H₁₄₄O₆P₂), Etc.
Examples of the compound represented by the general formula (III) include bis (2,2
4-di-t-butylphenyl) pentaerythritol di
Phosphite (C₃₃H₅₀O₆P₂), Bis (2,6-di)
-T-butyl-3-methylphenyl) pentaerythritol
Ludiphosphite (C₃₅H₅₄O₆P₂), Bis (noni
Ruphenyl) pentaerythritol diphosphite (C
₃₅H₅₄O₆P₂), Dioctadecyl pentaerythritol
Ludiphosphite (C₄₁H₈₂O₆P₂) Etc.
It

In the method for producing the copolyester resin of the present invention, the amount of the organic phosphite compound used is
100 to the theoretical yield of the copolyester resin
The amount is preferably 5,000 ppm, and is preferably 200
More preferably, the amount is about 4,000 ppm,
It is particularly preferable that the amount is 300 to 3,000 ppm. In the present invention, as long as the organic phosphite compound is used as the phosphorus compound, for example, orthophosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, ethyl acid phosphate,
Conventionally used phosphorus compounds such as phosphorous acid, trimethylphosphite, triethylphosphite and triphenylphosphite may be used in combination.

As the polycondensation catalyst in the present invention,
A conventionally used catalyst is used as a polycondensation catalyst for polyester resins, for example, diantimony trioxide,
Metal oxides such as germanium dioxide and germanium tetroxide, or organic acid salts such as antimony, germanium and titanium are used alone or in combination, or further, organic acid salts such as magnesium and cobalt are used together. To be The amount used is preferably 10 to 400 ppm, and more preferably 30 to 300 ppm, based on the theoretical yield of the copolyester resin.

The method for producing the copolyester resin of the present invention is basically a conventional method for producing a polyester resin using a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component. . That is, a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component are esterified in an esterification reaction tank, and the obtained esterification reaction product is transferred to a polycondensation tank and melt-polycondensed. Direct polymerization method, a dicarboxylic acid component containing an ester-forming derivative of terephthalic acid as a main component and a diol component containing ethylene glycol as a main component are transesterified in an esterification reaction tank to obtain an ester exchange reaction product. Transesterification method in which the compound is transferred to a polycondensation tank and melt-polycondensed, or
The esterification reaction product obtained in the above in the esterification reaction tank is a slurry prepared by dispersing a dicarboxylic acid component containing terephthalic acid as a main component in a diol component containing ethylene glycol as a main component in a slurry preparation tank. Alternatively, it is continuously added to the transesterification reaction product and esterified under normal pressure, and the obtained reaction product is continuously or / or
Alternatively, a continuous direct polymerization method or the like, in which the polycondensation is carried out stepwise and melt polycondensation is carried out, can be adopted.

Further, usually, the resin obtained by melt polycondensation is drawn out in a strand form from an outlet provided at the bottom of the polycondensation tank, and is cut with a cutter while cooling with water or after water cooling into pellets. Further, by subjecting the pellets after the polycondensation to heat treatment for solid-phase polymerization, it is possible to further increase the degree of polymerization and also to reduce acetaldehyde, low-molecular-weight oligomers and the like which are reaction by-products. .

In the above-mentioned production method, the esterification reaction or transesterification reaction is carried out at a temperature of about 200 to 270 ° C. and a pressure of about 1 × 10 ⁵ to 4 × 10 ⁵ Pa, and the esterification reaction rate is Usually 90% or more, preferably 93% or more, and then transferred to melt polycondensation, the melt polycondensation, in the presence of the polycondensation catalyst and the organic phosphite compound, a temperature of about 240 ~ 290 ℃, 13.3
It is performed under reduced pressure of about 1333 Pa.

In the solid phase polymerization, after pre-crystallization by heating at a temperature of about 120 to 200 ° C. for 1 minute or more, a temperature of about 180 to 240 ° C. and an inert gas such as nitrogen gas are used. Under atmosphere or / and 13.3 to 1333 Pa
It is done under reduced pressure.

In the present invention, the introduction of the organic phosphite compound into the polymerization system is preferably carried out at the same time as or before the introduction of the phenylenedioxydiacetic acid compounds into the polymerization system. Diacetic acid can be introduced into the polymerization system by esterification reaction between the dicarboxylic acid component excluding phenylenedioxydiacetic acid component and the diol component or esterification at any time from the start of transesterification reaction to the start of polycondensation. The reaction or transesterification reaction product is preferably present.

Here, the phenylenedioxydiacetic acids are added in the presence of the product of the esterification reaction or transesterification reaction at any time from the start of the esterification reaction or transesterification reaction to the start of the polycondensation reaction. Specifically, for example, any ester immediately after the start of the esterification reaction or transesterification reaction, during the esterification reaction or transesterification reaction, or after the end of the esterification reaction or transesterification reaction The product of the esterification reaction or transesterification reaction is added to the esterification reaction tank, to the transfer pipe during the transfer from the esterification reaction tank to the polycondensation tank, or to the polycondensation tank after the transfer. The method of is mentioned. Among them, it is preferable to add the product of the esterification reaction or the transesterification reaction after the completion of the esterification reaction or the transesterification reaction to the polycondensation tank after the transfer.

When the phenylenedioxydiacetic acid is introduced into the reaction system in the esterification reaction tank before and at the start of the esterification reaction or transesterification reaction, and the esterification reaction or transesterification reaction When the polycondensation tank before transfer to the polycondensation tank of the reaction product after the end is used, thermal deterioration of the phenylenedioxydiacetic acids is likely to occur, and the color tone of the obtained copolyester resin is poor. It becomes a tendency.

The organic phosphite compound and the phenylenedioxydiacetic acid are introduced into the reaction system at that time as the organic phosphite compound, the phenylenedioxydiacetic acid powder, and the organic phosphite. Any form such as a slurry form in which a phyto compound or phenylenedioxydiacetic acid is dispersed in the diol component, or a solution form in which an organic phosphite compound or phenylenedioxydiacetic acid is dissolved in the diol component is used. Although it is obtained, it is preferably in the form of a slurry in which it is dispersed in a diol component or a solution in which it is dissolved.

The copolyester resin obtained by the production method of the present invention has, as a color tone, a color coordinate b in the Hunter color difference formula defined in Reference 1 of JIS Z8730.
The value (a guideline for yellow / blue) is preferably -3 to +
6, more preferably -2 to +5.

The copolyester resin obtained by the production method of the present invention is molded into a preform by injection molding and then stretch blow molding, or a parison molded by extrusion molding is blow molded. As a result, it is molded into a bottle, etc.
After being formed into a sheet by extrusion molding, it is formed into a tray, a container, or the like by thermoforming, or the sheet is biaxially stretched to form a film, which is particularly useful in the field of food packaging.

Among them, the preform obtained by injection molding is suitable for molding a bottle by a stretch blow molding method such as a cold parison method in which it is biaxially stretched after being reheated. Alcoholic beverages, beverages such as tea and mineral water, soy sauce, sauces,
It is preferably used as a container for liquid seasonings such as mirin and dressing.

[0033]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A batch type polymerization apparatus equipped with a slurry preparation tank, a dissolution tank, an esterification reaction tank, a polycondensation tank, and a pelletizing apparatus was used, and an esterification reaction tank containing 50 kg of an esterification reaction product was used. Slurry of 15.8 kg / hr, which was prepared by slurrying terephthalic acid (43.6 kg) and ethylene glycol (19.6 kg) in a slurry preparation tank, was transferred under normal pressure to 250
The esterification reaction is carried out while continuously distilling the produced water at ℃, and when the esterification reaction rate reaches 95%, 50 kg of the reaction solution is left in the esterification reaction tank and transferred to the polycondensation tank. did.

On the other hand, 1,3-phenylenedioxydiacetic acid
Dissolve 4.52 kg and 4.97 kg of ethylene glycol
Dissolve while stirring at about 110 ℃ in the bath to make a solution
In addition, the solution was treated with an organic phosphite compound.
And bis (2,6-di-t-butyl-3-methylphenyl)
Le) pentaerythritol diphosphite (C₃₅H₅₄O
₆P₂) 0.025 kg was added and uniformly dispersed.

Subsequently, the phosphoric acid ethyl ester dissolved in ethylene glycol was added to the polycondensation tank to which the esterification reaction product was transferred so that the amount was 128 ppm with respect to the theoretical yield of the polyester resin. After the lapse of minutes, the above-mentioned organic phosphite compound was dispersed in 1,
An ethylene glycol solution of 3-phenylenedioxydiacetic acid was added at 3.82 kg (including 1,
The amount of 3-phenylenedioxydiacetic acid is 1.82 kg, which corresponds to 3 mol% based on all dicarboxylic acid components,
Further, the organic phosphite compound corresponds to 500 ppm with respect to the theoretical yield of the copolyester resin. ) Was transferred from the dissolution tank, and after 10 minutes had passed, cobalt acetate dissolved in ethylene glycol as a polycondensation catalyst was 90 ppm with respect to the theoretical yield of the polyester resin, and diantimony trioxide dissolved in ethylene glycol was used as the polyester. After adding each so as to be the amount of 150 ppm with respect to the theoretical yield of resin, about 25 minutes over about 100 minutes
The temperature rises from 0 ° C to about 270 ° C and the atmospheric pressure changes to 133
While reducing the pressure to Pa and distilling ethylene glycol, a polycondensation reaction was carried out for 3 hours after the start of the pressure reduction, and was extracted in a strand form from an extraction port provided at the bottom of the polycondensation tank, cooled with water, and then pelletized with a cutter. To produce copolyester resin pellets.

With respect to the obtained copolyester resin pellets, changes in intrinsic viscosity, color tone and color tone at the time of melting were measured by the following methods, and the results are shown in Table 1.

<Intrinsic Viscosity> About 0.25 g of a resin sample was dissolved in about 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1) at 1.0 ° C. at 110 ° C. It cooled to 30 degreeC, and measured at 30 degreeC with the fully automatic solution viscometer ("2CH type DJ504" by a central Rika company).

<Color tone> The resin sample has a bottom surface diameter of about 30.
A color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.) filled in a cylindrical powder color measuring cell having a size of 12 mm and a height of about 12 mm.
The color coordinate b value in the Hunter color difference formula defined in Reference 1 of JIS Z8730 was calculated as a simple average value of the values measured at four points by rotating the cell by about 90 degrees by the reflection method.

<Change in color tone during melting> 30 g of a resin sample was filled in a glass test tube and dried at 160 ° C. for 2.5 hours under a vacuum of 0.5 mmHg or less, and then at 290 ° C. in a nitrogen gas atmosphere. The melted state was maintained for 1 hour, then the bottom of the test tube was cracked, the resin was extracted in the form of strands, cooled with water, and then cut into pellets. The color coordinate b ′ value of the pellet was measured by the above method, and the color coordinate b
The difference from the value Δb (b′−b) was calculated.

Comparative Example 1 A copolyester resin was produced in the same manner as in Example 1 except that triphenylphosphite (C ₁₈ H ₂₁ O ₃ P) was used instead of the organic phosphite compound in Example 1. Then, with respect to the obtained copolyester resin, changes in intrinsic viscosity, color tone, and color tone during melting were measured, and the results are shown in Table 1.

Comparative Example 2 A copolymerized polyester resin was produced in the same manner as in Example 1 except that orthophosphoric acid (H ₃ PO ₄ ) was used instead of the organic phosphite compound in Example 1. With respect to the copolyester resin, changes in intrinsic viscosity, color tone, and color tone during melting were measured, and the results are shown in Table 1.

Example 2 Tris (2,4-di-t) as an organic phosphite compound
-Butylphenyl) phosphite (C ₄₂ H ₂₁ O ₃ P) was used in the same manner as in Example 1 except that the amount used was 1,000 ppm with respect to the theoretical yield of the copolyester resin. A copolyester resin was produced in the following manner, and the resulting copolyester resin was measured for the intrinsic viscosity, the color tone, and the change in the color tone during melting, and the results are shown in Table 1.

[0044]

[Table 1]

[0045]

According to the present invention, in copolymerizing phenylenedioxydiacetic acids as a dicarboxylic acid component for imparting gas barrier properties, the color tone is excellent and
It is possible to provide a method for producing a copolyester resin in which coloring in a molten state is suppressed.

Claims (7)

[Claims] 1. A polycondensation of a dicarboxylic acid component containing terephthalic acid as a main component and a phenylenedioxydiacetic acid as a copolymerization component and a diol component containing ethylene glycol as a main component through an esterification reaction or an ester exchange reaction. In producing a copolymerized polyester resin by polycondensing in the presence of a catalyst and a phosphorus compound, an organic phosphite compound having 20 to 120 carbon atoms is used as the phosphorus compound. Method. 2. The organic phosphite compound has the following general formula:
A group consisting of compounds represented by (I), (II), and (III)
The compound according to claim 1, which is any compound selected from
Process for producing copolyester resin. [Chemical 1] [R in formula (I)¹And R²R in formula (II)³And R^Four,as well as
R in formula (III)^FiveAnd R ⁶Are each independently an aliphatic group,
Represents an alicyclic group or an aromatic group, and X in the formula (II) is divalent
Or a trivalent aliphatic group, an alicyclic group, or an aromatic group,
n is 1 or 2. ] 3. The amount of the organic phosphite compound used is 100 to 5, relative to the theoretical yield of the copolyester resin.
The method for producing the copolyester resin according to claim 1 or 2, wherein the amount is 000 ppm. 4. The copolymerization according to claim 1, wherein the introduction of the organic phosphite compound into the polymerization system is carried out simultaneously with or before the introduction of the phenylenedioxydiacetic acid compounds into the polymerization system. Method for producing polyester resin. 5. Introduction of phenylenedioxydiacetic acids into a polymerization system from after initiation of esterification reaction or transesterification reaction of dicarboxylic acid component excluding phenylenedioxydiacetic acids and diol component to initiation of polycondensation. The method for producing a copolyester resin according to claim 4, wherein the esterification reaction or the transesterification reaction product is present in any one of the steps. 6. The method for producing a copolyester resin according to claim 1, wherein the ratio of the phenylenedioxydiacetic acids to the total dicarboxylic acid component is 0.1 to 20 mol%. 7. A phenylenedioxydiacetic acid is 1,3
-Phenylenedioxydiacetic acid, The manufacturing method of the copolyester resin in any one of Claim 1 thru | or 6.