JP7067048B2 - Polyester resin composition and its manufacturing method - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a polyester resin composition having excellent heat resistance and hydrolysis resistance, and having a small amount of gel composition, linear oligomer generated, cyclic oligomer content and increase generated in melt molding or processing steps, and a method for producing the same. It is about.

Polyester resin has excellent mechanical properties, thermal properties, chemical resistance, electrical properties, and moldability, and is used for various purposes. Among polyester resins, polyethylene terephthalate (hereinafter referred to as PET) is widely used in applications requiring high quality such as optical films and mold release films because of its excellent transparency and processability. .. However, linear oligomers such as PET monomer components and low molecular weight bodies (oligomer components) are generated and increased by the decomposition reaction of the polyester resin, which volatilizes and scatters during molding and processing, which may cause surface stains on the molded product. be. In addition, the scattering of the linear oligomer may cause process stains, which causes a problem of deterioration of the quality of the molded product due to surface stains and process stains. Further, the polyester resin is thermally deteriorated and oxidatively deteriorated during melt molding to generate a gel composition, which causes a problem of process contamination such as stains on the mouthpiece. Further, in film applications and the like, this gel composition has a defect of bright spots in the film, and the quality is deteriorated. In recent years, the demand for quality of optical films and mold release films has been increasing, and polyester resins that suppress the generation of linear oligomers and gel compositions that cause surface stains and process stains as described above are desired. It is rare. Various studies have been made on these issues.

For example, Patent Documents 1 and 2 disclose techniques for reducing the oligomer content in a polyester resin and the amount of oligomer regeneration during melting by performing solid phase polymerization and deactivation treatment.

Further, Patent Document 3 discloses a technique of suppressing the scattering of linear oligomers by containing an ionic liquid in polyester.

Further, Patent Document 4 discloses a technique of controlling the molar ratio of the amount of metal and the amount of phosphorus in a high range to suppress the gel composition.

Japanese Patent Application Laid-Open No. 2003-176347 Japanese Unexamined Patent Publication No. 2011-32421 WO2016 / 167084 Japanese Patent Application Laid-Open No. 2003-96280

As in the conventional technique described above, solid phase polymerization and deactivation treatment only reduce the amount of linear oligomers and cyclic oligomers contained in the polyester resin before molding, and are different from thermal decomposition and hydrolysis at the time of melting. Since there is no effect on the linear oligomers that are generated and increased by the mechanism, it was not possible to prevent surface stains on the product and stains on the processing process. In addition, when an ionic liquid is added to suppress the scattering of linear oligomers, or when the molar ratio of metal to phosphorus is set to a high range to suppress gel, heat resistance and hydrolysis resistance deteriorate. There was a problem.

An object of the present invention is a polyester resin composition having excellent heat resistance and hydrolysis resistance, and having a small amount of gel composition, linear oligomer generated, cyclic oligomer content and increase generated in a melt molding or processing process, and a polyester resin composition thereof. The purpose is to provide a manufacturing method.

In order to solve the above problems, the present invention has the following features.
(1) It is made of phosphoric acid and sodium phosphate salt, contains an antimony element, satisfies the following formulas (I) to (IV) and (VII), and contains a total amount of elements selected from nitrogen, sulfur and halogen. A polyethylene terephthalate resin composition characterized by an amount of less than 10 ppm .
Amount of linear oligomer generated ≤ 900ppm (I)
Cyclic trimer content ≤ 0.6 wt% (II)
5ppm ≤ Mn content ≤ 40ppm (III)
4ppm ≤ Na content ≤ 60ppm (IV)
17ppm ≤ P content ≤ 50ppm (VII)
The linear oligomer is the total amount of terephthalic acid, monohydroxyethyl terephthalate, and bishydroxyterephthalate, and the linear oligomer generation amount is polyethylene that has been allowed to stand in an environment of a temperature of 23 ° C. and a humidity of 50% for 24 hours or more. It is the amount of increase in linear oligomer when the terephthalate resin is heat-treated at 290 ° C. for 20 minutes under nitrogen.
(2) IV (inherent viscosity) of polyester when the dicarboxylic acid component or its ester-forming derivative component and the diol component are subjected to an esterification reaction or an ester exchange reaction, and then melt polymerization and solid phase polymerization are carried out to produce polyester. A manganese compound and an antimony compound are added at a stage of 0.4 or less, and a phosphoric acid and a sodium phosphate salt are added at a stage until the completion of the polycondensation reaction, and the content thereof is the following formula (V), ( A method for producing a polyethylene terephthalate resin composition, which satisfies VI) and (VIII) and has a total content of an element selected from nitrogen, sulfur and halogen of less than 10 ppm .
5ppm ≤ Mn content ≤ 40ppm (V)
4ppm ≤ Na content ≤ 60ppm (VI)
17ppm ≤ P content ≤ 50ppm (VIII)

According to the present invention, there is provided a polyester resin composition having excellent heat resistance and hydrolysis resistance, and having a gel composition generated in a melt molding or a processing step, a linear oligomer generation amount, a cyclic oligomer content, and a small increase amount. It is possible to provide high-quality films such as optical films and release films.

The present invention will be described in detail below.
The polyester resin used in the present invention refers to a polyester resin obtained by polycondensing a dicarboxylic acid component and a diol component.

As the dicarboxylic acid component in the present invention, various dicarboxylic acid components such as aromatic dicarboxylic acid, chain aliphatic dicarboxylic acid, and alicyclic dicarboxylic acid can be used. Among them, the aromatic dicarboxylic acid and its ester-forming derivative component are preferable from the viewpoint of mechanical properties, heat resistance and hydrolysis resistance of the polyester resin composition. In particular, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and their ester-forming derivative components are preferable from the viewpoint of polymerizable and mechanical properties.

As the dicarboxylic acid component in the present invention, various dicarboxylic acid components such as aromatic dicarboxylic acid, chain aliphatic dicarboxylic acid, and alicyclic dicarboxylic acid can be used. Among them, the aromatic dicarboxylic acid and its ester-forming derivative component are preferable from the viewpoint of mechanical properties, heat resistance and hydrolysis resistance of the polyester resin composition. In particular, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and their ester-forming derivative components are preferable from the viewpoint of polymerizable and mechanical properties.

Various diols can be used as the diol component in the present invention. For example, as an aliphatic diol such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, or an alicyclic diol. Are various alicyclic diols such as cyclohexanedimethanol and cyclohexanediethanol, bisphenol A, bisphenol S, styrene glycol, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9'-bis ( An aromatic ring-type diol such as 4-hydroxyphenyl) fluorene can be exemplified. In addition to diols, polyfunctional alcohols such as trimethylolpropane and pentaerythritol can also be used.

Among these, diols having a boiling point of 230 ° C. or lower are preferable because they are easily distilled out of the reaction system, and aliphatic diols are more preferable because they are low in cost and have high reactivity. Further, ethylene glycol is particularly preferable from the viewpoint of mechanical properties.

In addition, other dicarboxylic acid components, hydroxycarboxylic acid derivatives, and diol components may be copolymerized to the extent that the scope of the effect of the present invention is not impaired.

The polyester resin composition of the present invention needs to generate 900 ppm or less of linear oligomers. The amount of linear oligomer generated is the amount of increase in linear oligomer when the polyester resin composition left to stand in an environment of temperature 23 ° C. and humidity 50% for 24 hours or more is heat-treated at 290 ° C. for 20 minutes under nitrogen. Is. Normally, polyester resin is dried before melting to suppress hydrolysis. Since the linear oligomer is also generated by the hydrolysis of the polyester resin, it is preferable to dry it before the melting process. However, even if the polyester resin is in an undried state, the drying step can be omitted if the generation of the linear oligomer can be suppressed. This can result in a significant cost reduction. According to the present invention, by improving the heat resistance and hydrolysis resistance of the polyester resin, the amount of linear oligomers generated can be dramatically reduced even when the water content is high.

In the present invention, the linear oligomer is a monomer component or an oligomer component generated by a decomposition reaction such as thermal decomposition, hydrolysis, or oxidative decomposition of a polyester resin, and specifically, a dicarboxylic acid component constituting the polyester resin or a dicarboxylic acid component. It refers to a chain-like reactant formed by the reaction between the carboxyl group of a dicarboxylic acid and the hydroxyl group of a diol, and does not include a cyclic oligomer such as a cyclic trimer. Specifically, it is a monoester or diester with a dicarboxylic acid monomer and a glycol component. This linear oligomer is prone to sublimation and precipitation, and causes process stains and surface stains on the molded product in processing processes such as melt molding.

Examples of PET, which is a typical polyester resin, are TPA (terephthalic acid), MHET (monohydroxyethyl terephthalate) and BHET (bishydroxyethyl terephthalate), which are reactants of terephthalic acid and ethylene glycol. The total amount of these linear oligomers needs to be 900 ppm or less, preferably 800 ppm or less, and more preferably 700 ppm or less. By setting the amount of the linear oligomer generated within the above range, it is possible to reduce the process stains and surface stains caused by the linear oligomer, which are problems during the molding process.

The polyester resin composition of the present invention needs to have a cyclic oligomer content of 0.6 wt% or less, preferably 0.45 wt% or less. The cyclic oligomer is a cyclic oligomer composed of a dicarboxylic acid component and a diol component constituting the polyester resin, and a cyclic trimer is particularly likely to be formed. When the molded product such as a film or fiber is heated or exposed to a solvent, the cyclic oligomer is deposited on the surface of the molded product, which causes surface defects and stains, which causes a problem. The polyester resin composition of the present invention reduces the content of the cyclic oligomer by carrying out solid phase polymerization.

The content of the cyclic oligomer can be reduced by solid phase polymerization, but it is regenerated and increased at the time of melting such as melt molding of the poly-SL resin composition. Therefore, in the polyester resin composition of the present invention, the amount of increase in the cyclic oligomer is preferably 0.3 wt% or less, more preferably 0.25 wt% or less. The amount of increase in the cyclic oligomer is the amount of increase in the melting treatment at 300 ° C. for 15 minutes under nitrogen. Since the cyclic oligomer is produced by an equilibrium reaction with polyester, there is a saturated amount in its content. Therefore, the amount of increase in the cyclic oligomer when solid phase polymerization is not carried out is substantially 0, but this is only in a saturated state, and the cyclic oligomer in the polyester resin composition is not reduced. In the present invention, solid-phase polymerization is carried out to reduce the content of cyclic oligomers, and then the amount of increase in cyclic oligomers regenerated during remelting in a processing step or the like is suppressed by diligently examining the catalyst composition.

Further, the polyester resin composition of the present invention preferably has a value of ΔCOOH / COOH, which is an index of hydrolysis resistance, of 2.0 or less. This ΔCOOH is the amount of increase in COOH terminal groups when subjected to a wet heat treatment at 155 ° C. for 4 hours under saturated steam, and the smaller the value of ΔCOOH / COOH divided by the amount of COOH terminal groups before treatment, the more hydrolysis resistant. The sex becomes good. The ΔCOOH / COOH is preferably 2.0 or less, more preferably 1.9 or less. Within the above range, the hydrolysis resistance is good, and the generation of linear oligomers due to hydrolysis can be suppressed.

As represented by the following formula (III), the polyester resin composition of the present invention needs to contain a manganese element of 5 ppm or more and 40 ppm or less.

5ppm ≤ Mn content ≤ 40ppm (III)
The lower limit is preferably 10 ppm or more. The upper limit is preferably 30 ppm or less. By setting it to the above lower limit or more, the gel composition generated during melt molding can be suppressed, so that the defects of the molded product can be suppressed. In addition, the manganese element contributes to thermal decomposition, oxidative decomposition, and hydrolysis of polyester because it has high catalytic activity even in a heat treatment at a relatively low temperature below the melting point of polyester such as a film stretching step. Therefore, by satisfying the amount of manganese element below the above upper limit, it is possible to reduce the amount of linear oligomer generated and the amount of increase in cyclic oligomer in the processing step.

Further, the polyester resin composition of the present invention needs to contain 4 ppm or more and 60 ppm or less of the sodium element as represented by the following formula (IV).

4ppm ≤ Na content ≤ 60ppm (IV)
The lower limit is preferably 10 ppm or more. The upper limit is preferably 40 ppm or less. Within the above range, the hydrolysis resistance is improved, and the generation of linear oligomers due to hydrolysis can be suppressed.

Further, the polyester resin composition of the present invention preferably contains a phosphorus element of 17 ppm or more and 70 ppm or less. The lower limit is preferably 20 ppm or more, more preferably 25 ppm or more. The upper limit is preferably 60 ppm or less, more preferably 50 ppm or less. Within the above range, the amount of linear oligomers generated and the amount of cyclic oligomers increased in the processing process can be reduced.

Further, in the polyester resin composition of the present invention, it is preferable that Na / P, which is the molar ratio of the contents of the sodium element and the phosphorus element, is 0.3 or more and 1.2 or less. The lower limit is preferably 0.4 or more, and the upper limit is preferably 1.0 or less. Within the above range, hydrolysis resistance can be imparted, and the amount of linear oligomer generated in the processing step can be reduced.

The polyester resin composition of the present invention preferably has an antimony element content of 50 ppm or more and 150 ppm or less. The lower limit is preferably 80 ppm or more, and the upper limit is preferably 120 ppm or less. Within the above range, it is possible to reduce the increase in the amount of cyclic oligomers regenerated during melt molding of the polyester resin composition without impairing the polymerization reactivity.

The polyester resin composition of the present invention preferably has a total content of elements selected from nitrogen, sulfur and halogen of less than 10 ppm. It is more preferably less than 5 ppm, still more preferably less than 3 ppm. Compounds containing elements such as nitrogen, sulfur and halogen promote thermal decomposition and hydrolysis when present in polyester. Therefore, it is most preferable not to include it. By satisfying the above range, the amount of linear oligomer generated in the processing process can be reduced.

Further, the polyester resin composition of the present invention preferably has a gelation rate of 7 wt% or less when heat-treated at 300 ° C. for 6 hours in a nitrogen atmosphere having an oxygen concentration of 1%. More preferably, it is 5 wt% or less. Within the above range, the gel composition generated during melt molding can be suppressed, so that the defects of the molded product can be suppressed.

Next, a method for producing the polyester resin composition of the present invention will be described.

In the polyester resin composition of the present invention, a dicarboxylic acid component or an ester-forming derivative component thereof is subjected to an esterification reaction or an ester exchange reaction with a diol component, and then a polycondensation reaction and a solid phase polymerization are carried out to produce a polyester. A manganese compound is added at the stage where the IV (inherent viscosity) of the polyester is 0.4 or less, and phosphoric acid and an alkali metal phosphate are added at the stage until the completion of the polycondensation reaction, and the content thereof is as follows. It can be obtained by satisfying (V) and (VI).

5ppm ≤ Mn content ≤ 40ppm (V)
4ppm ≤ Alkali metal element content ≤ 60ppm (VI)
In the method for producing a polyester resin composition of the present invention, it is necessary to add the manganese compound at a stage where the IV (intrinsic viscosity) of the polyester resin is 0.4 or less. By adding it in the above range, the polymerization reactivity becomes good and the dispersibility in the polyester resin becomes good, so that the transparency is enhanced. Among them, when the polyester oligomer is obtained by the transesterification reaction, it is preferable to add a manganese compound at the start of the transesterification reaction in order to proceed the reaction more efficiently. When the polyester oligomer is obtained by the esterification reaction, it is preferable to add the manganese compound at the stage where the IV of the polyester resin is 0.4 or less from the end of the esterification reaction, and the weight is increased from the end of the esterification reaction. It is more preferable to add it before the start of the condensation reaction. The esterification reaction is a self-catalyzed reaction with an acid component such as terephthalic acid, and the reaction proceeds sufficiently even without a catalyst. If a catalyst is contained, by-products such as dimer of the diol component increase. By carrying out without a catalyst and adding the ester before the viscosity of the polyester increases, the dispersibility of the manganese compound can be improved and high transparency can be exhibited without impairing the heat resistance.

In the method for producing a polyester resin composition of the present invention, the amount of the manganese compound added needs to satisfy the following formula (V) as the content of the manganese element in the polyester composition.

5ppm ≤ Mn content ≤ 40ppm (VII)
The lower limit is preferably 10 ppm or more. The upper limit is preferably 30 ppm or less. By setting it to the above lower limit or more, the gel composition generated during melt molding can be suppressed, so that the defects of the molded product can be suppressed. In addition, the manganese element contributes to thermal decomposition, oxidative decomposition, and hydrolysis of the polyester resin because it has high catalytic activity even in a heat treatment at a relatively low temperature below the melting point of the polyester such as a film stretching step. Therefore, by satisfying the amount of manganese element below the above upper limit, it is possible to reduce the amount of linear oligomer generated and the amount of increase in cyclic oligomer in the processing step.

The manganese compound is not particularly limited, and examples thereof include manganese acetate, manganese nitrate, manganese sulfate, and manganese chloride, and manganese acetate is preferable from the viewpoint of solubility and catalytic activity.

Further, the form of addition may be any of powder, slurry and solution, and it is preferable to add as a solution from the viewpoint of dispersibility. The solvent at this time is preferably the same as the diol component of the polyester resin composition, and in the case of polyethylene terephthalate, it is particularly preferable to use ethylene glycol.

In the method for producing a polyester resin composition of the present invention, it is necessary to add phosphoric acid and an alkali metal phosphate at a stage until the polycondensation reaction is completed. The timing for adding the phosphoric acid and the alkali metal phosphate is more preferably between the end of the transesterification reaction and the esterification reaction and the start of the polycondensation reaction. By adding it to the above range, it is possible to effectively impart thermal stability and hydrolysis resistance to the polyester resin without delaying the polycondensation reaction.

The amount of phosphoric acid added is not particularly limited, but the lower limit of the amount of phosphoric acid added is preferably 25 ppm or more, more preferably 45 ppm or more as the phosphorus element. The upper limit of the addition amount is preferably 200 ppm or less, more preferably 150 ppm or less. Within the above range, the thermal stability of the polyester resin composition can be improved without causing a delay in polymerization, and as a result, the amount of linear oligomers generated and the amount of cyclic oligomers increased in the processing step are reduced. be able to. Since phosphoric acid is usually available as an aqueous solution, the addition amount is the net addition amount of the phosphoric acid component converted from the concentration of the aqueous solution.

The amount of the alkali metal phosphate added needs to be 4 ppm or more and 60 ppm or less as the content of the alkali metal element in the polyester composition. The lower limit is more preferably 10 ppm or more. The upper limit is preferably 40 ppm or less. Within the above range, the hydrolysis resistance is improved, and the generation of linear oligomers due to hydrolysis can be suppressed.

Examples of the alkali metal phosphate include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, lithium dihydrogen phosphate, and phosphoric acid. Examples thereof include dilithium hydrogen and trilithium phosphate. From the viewpoint of hydrolysis resistance, sodium salts are preferable, and sodium dihydrogen phosphate is particularly preferable. Further, a plurality of phosphoric acid alkali metal salts may be used in combination.

Further, the form of addition may be any of powder, slurry and solution, and it is preferable to add as a solution from the viewpoint of dispersibility. The solvent at this time is preferably the same as the diol component of the polyester resin composition, and in the case of polyethylene terephthalate, it is particularly preferable to use ethylene glycol.

Further, it is preferable to mix and add a solution of phosphoric acid and an alkali metal phosphate. By mixing phosphoric acid and an alkali metal phosphate and adding it as a buffer solution, better hydrolysis resistance can be exhibited and the amount of linear oligomer generated in the processing step can be reduced.

Further, an alkali metal compound other than the alkali metal phosphate may be used in combination as long as the amount of the alkali metal element added is satisfied. Specific examples thereof include hydroxides of lithium, sodium and potassium, acetates, carbonates, nitrates and chlorides. Among these, by using potassium hydroxide in combination, the melt resistivity of the polyester resin required for the electrostatically applied film formation can be reduced without increasing the amount of linear oligomers generated, and the moldability is improved.

In the method for producing a polyester resin composition of the present invention, when the polyester resin composition is carried out through an esterification reaction, an additional glycol component such as ethylene glycol is added after the esterification reaction until the addition of the alkali metal phosphate. It is preferable to do so. More preferably, it is between the addition of the manganese compound and the addition of the alkali metal phosphate. Since the low molecular weight substance of the polyester resin composition obtained by the esterification reaction has a higher degree of polymerization than the low molecular weight substance obtained by the transesterification reaction, the alkali metal phosphate is difficult to disperse and foreign matter is likely to occur. Therefore, by additionally adding a glycol component such as ethylene glycol and lowering the degree of polymerization by depolymerization, it is possible to suppress foreign matter formation. At this time, if the manganese compound is present, depolymerization can be performed more efficiently.

The glycol component such as ethylene glycol to be additionally added is preferably 0.05 times mol or more and 0.5 times mol or less with respect to the total acid component. More preferably, it is 0.1 times mol or more and 0.3 times mol or less. Within the above range, it is possible to suppress the conversion of the alkali metal phosphate into a foreign substance without causing a delay in the polymerization time due to a temperature drop in the polymerization system.

As other catalysts used in the production of the polyester resin composition of the present invention, known transesterification catalysts, polycondensation catalysts, and co-catalysts can be used. For example, examples of the polymerization catalyst include, but are not limited to, antimony compounds, germanium compounds, titanium compounds, and aluminum compounds. Further, examples of the ester exchange catalyst and co-catalyst include, but are not limited to, manganese compounds, magnesium compounds, calcium compounds, cobalt compounds, zinc compounds, lithium compounds, sodium compounds, potassium compounds and the like.

Further, in the method for producing a polyester resin composition of the present invention, it is necessary to carry out solid phase polymerization. By carrying out solid phase polymerization, it is possible to reduce the number of cyclic oligomers and linear oligomers in the polyester resin composition. The conditions for solid phase polymerization are not particularly limited, but the polyester resin composition is preferably carried out at a melting point of −30 ° C. or lower, a melting point of −60 ° C. or higher, and a vacuum degree of 40 Pa or lower. The solid phase polymerization time is appropriately set depending on the content of the cyclic oligomer of the target polyester resin composition, IV, and the like, but is preferably 3 hours or more and 20 hours or less, as compared with the production time cycle.

Further, in the method for producing the polyester resin composition of the present invention, deactivation treatment may be carried out. The deactivation treatment is a step of inactivating the polycondensation catalyst remaining in the polyester resin composition, and by carrying out the deactivation treatment, the amount of increase in the cyclic oligomer when the polyester resin composition is remelted can be reduced. The deactivation treatment can be carried out by contacting the polyester resin composition with various solutions such as water, a phosphorus compound and an ammonia compound at room temperature or under heating. Phosphoric compounds include phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, dimethyl phosphate, diphenyl phosphate, methyl phosphate, and ethyl phosphate, as well as phosphoric acid and polyphosphoric acid. Examples thereof include, and are not limited to, an aqueous solution or a solution of a phosphorus compound such as. Examples of the ammonia compound include triethylamine, tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and the like. The treatment temperature is preferably 20 ° C. or higher and 120 ° C. or lower, more preferably 40 ° C. or higher and 100 ° C. or lower, and further preferably 50 ° C. or higher and 100 ° C. or lower. The treatment time is preferably 30 minutes or more and 24 hours or less, more preferably 1 hour or more and 12 hours or less.

The polyester resin composition of the present invention may be a terminal sealant, an antioxidant, an ultraviolet absorber, a flame retardant, a fluorescent whitening agent, a matting agent, a plasticizer or an antifoaming agent, as long as the effects of the present invention are not impaired. Other additives and the like may be blended as needed.

Hereinafter, specific examples of the method for producing a polyester resin composition in the present invention will be given, but the present invention is not limited thereto.

A slurry of terephthalic acid and ethylene glycol (1.15 times mol with respect to terephthalic acid) is gradually added to an esterification reactor charged with bishydroxyethyl terephthalate dissolved at 255 ° C. using a snake pump for esterification. Proceed with the reaction. The temperature in the reaction system is controlled to be 245 to 255 ° C., and the esterification reaction is terminated when the reaction rate reaches 95%.

The esterification reaction product at 255 ° C. thus obtained is transferred to a polymerization apparatus, and a manganese compound and a polycondensation catalyst are added. Then, ethylene glycol is additionally added, and phosphoric acid and an alkali metal phosphate are added. During these operations, it is preferable to keep the temperature in the reaction system at 240 to 255 ° C. so that the esterified product does not solidify.

Then, while gradually raising the temperature in the polymerization apparatus to 290 ° C., the pressure in the polymerization apparatus is gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the predetermined stirring torque is reached, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and the molten polymer is discharged into cold water in a strand shape and cut to obtain a pellet-shaped polymer.

The obtained pelletized polymer was dried at 160 ° C. for 6 hours, crystallized, and subjected to solid phase polymerization at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition.

The polyester resin composition of the present invention is excellent in heat resistance and hydrolysis resistance, and the amount of gel composition, linear oligomer generated, and cyclic oligomer generated in the melt molding and processing steps is small. Therefore, it can be suitably used for various applications such as films, fibers, and molded bodies, and in particular, the polyester film of the present invention can be used for high-quality films such as optical films and release films that require high transparency. ..

The film may be a single film film composed of the polyester resin composition of the present invention or a laminated film having at least one layer of the polyester resin composition of the present invention. In particular, in the case of a laminated film, a laminated film having a layer made of the polyester resin composition of the present invention on at least one surface is preferable. When the layer made of the polyester resin composition of the present invention is present on the film surface, volatilization of the linear oligomer from the film surface is suppressed, so that the occurrence of linear oligomer defects can be effectively suppressed.

Hereinafter, the present invention will be described in more detail with reference to examples. The physical property values in the examples were measured by the following methods. The method described below describes a measurement method in the case of a single component of the polyester resin composition of the present invention, but in the case of a molded body composed of a plurality of resins such as a laminated film, the resin of each layer is scraped off. Isolate and analyze.

(1) Intrinsic viscosity of polyester resin composition (IV)
It was measured at 25 ° C. using an o-chlorophenol solvent.

(2) The COOH terminal group amount of the polyester resin composition was measured by the method of Maurice. (References M.J. Maurice, F. Huizinga, Anal. Chem. Acta, 22, 363 (1960)).

(3) Manganese and phosphorus in the polyester resin composition, alkali metal element content Atomic absorption method (manufactured by Hitachi, Ltd .: polarized Zeeman atomic absorption spectrophotometric type 180-80, frame: acetylene air) was used for quantification.

(4) Nitrogen Element Content of Polyester Resin Composition The polyester resin composition was freeze-crushed and dried under reduced pressure at room temperature for 3 hours. Then, quantification was performed by ICP emission spectroscopic analysis method (ND-100 type manufactured by Mitsubishi Chemical Corporation).

(5) Sulfur and halogen element content of the polyester resin composition The polyester resin composition was freeze-crushed and dried under reduced pressure at room temperature for 3 hours. Then, the quantification was performed by a combustion ion chromatograph (ICA2000 manufactured by Toa DKK Corporation). At this time, less than 5 ppm was set to be below the lower limit of detection (ND).

(6) Gelation rate of polyester resin composition The polyester resin composition was pulverized by a freeze pulverizer (manufactured by Splex CertiPerp), and 0.5 g was weighed in a stainless beaker having a capacity of 50 ml. After vacuum drying at 50 ° C. for 2 hours using a vacuum dryer, heat treatment was performed at 300 ° C. for 6 hours under a gas flow with an oxygen / nitrogen concentration of 1% (flow rate 0.5 L / min). This was dissolved in 20 ml of o-chlorophenol at 160 ° C. for 1 hour and allowed to cool. This solution was filtered using a glass filter (3GP40 manufactured by Shibata Scientific Technology Co., Ltd.), and the glass filter was washed with dichloromethane. The glass filter was dried at 130 ° C. for 2 hours, and the weight fraction with respect to the polyester weight (0.5 g) was obtained from the increase in the weight of the filter before and after filtration, and the gelation ratio (%) was obtained.

(7) Evaluation of hydrolysis resistance of polyester resin composition (ΔCOOH / COOH)
The polyester resin composition was wet-heated at 155 ° C. for 4 hours under saturated steam, and the amount of COOH terminal groups before and after the treatment was measured to calculate the amount of COOH terminal group increase (ΔCOOH = COOH after treatment-COOH before treatment). .. Hydrolysis resistance was evaluated by dividing this ΔCOOH value by the amount of COOH terminal groups before treatment.
The following heat treatment equipment was used as the treatment equipment.
PRESSER COOKER 306SIII (manufactured by HIRAYAMA Mfg. Co., Ltd.).

(8) Amount of linear oligomer generated in the polyester resin composition 0.1 g of the polyester resin composition (moisture content 2500 ppm) left to stand in an environment of temperature 23 ° C. and humidity 50% for 24 hours or more is weighed, and the inside of the sealed tube is nitrogen. Under the atmosphere, the melting treatment was performed at 290 ° C. for 20 minutes. After dissolving the sample in the melt-treated sealed tube with 2 mL of HFIP (hexafluoro-2-propanol) / chloroform = 1/1 (volume) mixed solution, transfer to a beaker, add 3 mL of chloroform, and add 40 mL of methanol. Added gradually. Then, 0.5 mL of DMF (N, N-dimethylformamide) was added to the residue obtained by concentrating and drying the solution obtained by filtering with a paper filter (No. 2 manufactured by ADVANTEC) to dissolve and disperse the solution. Ethanol was added and the volume was adjusted to 5 mL. A solution filtered through a PTFE membrane filter having a pore size of 0.45 μm was used as a sample solution. The obtained sample solution was analyzed by LC / UV to measure the content of linear oligomers (TPA, MHET, BHET) in the polyester resin composition after the melting treatment. At this time, the amount of linear oligomer generated was determined by calculating the difference in the content of linear oligomers before and after the melting treatment (content after melting treatment-content before melting treatment).

(9) Cyclic oligomer content Orthochlorophenol was used as a solvent, and the measurement was performed by a liquid chromatograph.

Equipment: Shimadzu LC-10ADvp
Column: YMC-Pack ODS-A 150 x 4.6 mm S-5 μm
Column temperature: 40 ° C
Flow rate: 1.3 ml / min
Detector: 240nm
Eluent: Liquid A, pure water 35%, liquid B, methanol 75%.

(10) Increased amount of cyclic oligomers 8 g of the polyester resin composition was vacuum dried at 150 ° C. for 8 hours. The dried polyester resin composition was melted at 300 ° C. for 15 minutes in a nitrogen atmosphere. The content of the cyclic oligomer of the polymer after the melting treatment was measured in the same manner as in (9) above, and the amount of increase in the cyclic oligomer was calculated by comparing before and after the melting treatment.

(Example 1)
In an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C., a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times mol with respect to terephthalic acid) was gradually added. Was added to promote the esterification reaction. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was terminated when the reaction rate reached 95%.

105 parts by weight (equivalent to 100 parts by weight of PET) of the esterification reaction product at 255 ° C. thus obtained was transferred to a polymerization apparatus, and 0.01 part by weight of manganese acetate tetrahydrate was transferred to an ethylene glycol solution (23 ppm as a manganese element). 0.012 parts by weight of diantimonate oxide was added to the ethylene glycol slurry. Then, 5 parts by weight of ethylene glycol (0.15 times by weight of the terephthal component) was additionally added to proceed with depolymerization, and then 0.006 parts by weight of phosphoric acid and 0.0095 parts by weight of sodium dihydrogen phosphate dihydrate were added. A mixed ethylene glycol solution (14 ppm as sodium element) was added.

Then, while gradually raising the temperature inside the polymerization apparatus to 290 ° C., the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the melt viscosity equivalent to the intrinsic viscosity of 0.55 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 1.

The polyester resin composition obtained in Example 1 has good gelation rate and hydrolysis resistance, and has a small amount of linear oligomers generated, a cyclic oligomer content, and an increase, so that it is an optical film or a release film. It had suitable physical properties.

(Examples 2 to 5, Comparative Examples 1 to 3)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amounts of the manganese compound and phosphoric acid were changed as shown in Table 1. The characteristics of the obtained polyester resin composition are shown in Table 1.

The polyester resin compositions obtained in Examples 2 to 5 have good gelation rate and hydrolysis resistance, and have a small amount of linear oligomer generation, cyclic oligomer content, and increase, so that they can be used as an optical film or an optical film. It had suitable physical properties for a release film.

Since the polyester resin composition obtained in Comparative Example 1 did not contain a manganese compound, the gelation rate and ΔCOOH / COOH increased.

In the polyester resin compositions obtained in Comparative Examples 2 and 3, since the amount of the manganese compound added was large, the amount of ΔCOOH / COOH generated and the amount of linear oligomer increased and the amount of cyclic oligomer increased increased.

(Comparative Example 4)
A polyester resin composition was obtained in the same manner as in Example 1 except that solid phase polymerization was not carried out. The characteristics of the obtained polyester resin composition are shown in Table 1.

Since the polyester resin composition obtained in Comparative Example 4 was not subjected to solid phase polymerization, the content of the cyclic oligomer was increased.

（実施例６～９、比較例５，６）
リン酸アルカリ金属塩の添加量を表２の通りに変更した以外は、実施例１と同様の方法でポリエステル樹脂組成物を得た。得られたポリエステル樹脂組成物の特性を表２に示す。
実施例６～９で得られたポリエステル樹脂組成物は、ゲル化率および耐加水分解性が良好であり、線状オリゴマー発生量、環状オリゴマー含有量及び増加量も少ないことから、光学フィルムや離型フィルムに好適な物性を有していた。

(Examples 6 to 9, Comparative Examples 5 and 6)
A polyester resin composition was obtained in the same manner as in Example 1 except that the amount of the alkali metal phosphate added was changed as shown in Table 2. The characteristics of the obtained polyester resin composition are shown in Table 2.
The polyester resin compositions obtained in Examples 6 to 9 have good gelation rate and hydrolysis resistance, and the amount of linear oligomer generated, the content of cyclic oligomer, and the amount of increase are small, so that they can be used as an optical film or released. It had suitable physical properties for a mold film.

Since the polyester resin composition obtained in Comparative Example 5 did not contain the alkali metal phosphate, the amount of ΔCOOH / COOH and linear oligomer generated increased.

In the polyester resin composition obtained in Comparative Example 6, the amount of ΔCOOH / COOH and the amount of linear oligomer generated increased because the amount of the alkali metal phosphate added was large.

（実施例１０～１２、比較例７）
リン酸の添加量を表３の通りに変更した以外は、実施例１と同様の方法でポリエステル樹脂組成物を得た。得られたポリエステル樹脂組成物の特性を表３に示す。
実施例１０～１２で得られたポリエステル樹脂組成物は、ゲル化率および耐加水分解性が良好であり、線状オリゴマー発生量、環状オリゴマー含有量及び増加量も少ないことから、光学フィルムや離型フィルムに好適な物性を有していた。

(Examples 10 to 12, Comparative Example 7)
A polyester resin composition was obtained in the same manner as in Example 1 except that the amount of phosphoric acid added was changed as shown in Table 3. The characteristics of the obtained polyester resin composition are shown in Table 3.
The polyester resin compositions obtained in Examples 10 to 12 have good gelation rate and hydrolysis resistance, and the amount of linear oligomer generated, the content of cyclic oligomer, and the amount of increase are small, so that they can be used as an optical film or released. It had suitable physical properties for a mold film.

Since the polyester resin composition obtained in Comparative Example 7 did not contain phosphoric acid, the amount of ΔCOOH / COOH generated and the amount of linear oligomer increased and the amount of cyclic oligomer increased increased.

（実施例１３）
２５５℃にて溶解したビスヒドロキシエチルテレフタレート１０５重量部が仕込まれたエステル化反応器に、テレフタル酸８６重量部とエチレングリコール３７重量部（テレフタル酸に対し１．１５倍モル）からなるスラリーを徐々に添加し、エステル化反応を進行させた。反応系内の温度は２４５～２５５℃になるようにコントロールし、反応率が９５％に到達した段階でエステル化反応を終了とした。

(Example 13)
In an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C., a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times mol with respect to terephthalic acid) was gradually added. Was added to promote the esterification reaction. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was terminated when the reaction rate reached 95%.

105 parts by weight (equivalent to 100 parts by weight of PET) of the esterification reaction product at 255 ° C. thus obtained was transferred to a polymerization apparatus, and 0.01 part by weight of manganese acetate tetrahydrate was transferred to an ethylene glycol solution (23 ppm as a manganese element). 0.012 parts by weight of ethylene glycol slurry and 0.0008 parts by weight of potassium hydroxide solution were added. Then, 5 parts by weight of ethylene glycol (0.15 times by weight of the terephthal component) was additionally added to proceed with depolymerization, and then 0.006 parts by weight of phosphoric acid and 0.0095 parts by weight of sodium dihydrogen phosphate dihydrate were added. A mixed ethylene glycol solution (14 ppm as sodium element) was added.

Then, while gradually raising the temperature inside the polymerization apparatus to 290 ° C., the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the melt viscosity equivalent to the intrinsic viscosity of 0.62 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 4.

The polyester resin composition obtained in Example 13 has good gelation rate and hydrolysis resistance, and has a small amount of linear oligomers generated, a cyclic oligomer content, and an increase, and thus is an optical film or a release film. It had suitable physical properties.

(Example 14)
Weighed 101.0 parts by weight of dimethyl terephthalate and 64.6 parts by weight of ethylene glycol (twice the molar amount of the dicarboxylic acid component), and charged them into a transesterification reaction apparatus. After dissolving the contents at 150 ° C., 0.018 parts by weight of manganese acetate tetrahydrate in ethylene glycol solution (40 ppm as manganese element) and 0.012 parts by weight of diantimone trioxide were added and stirred. .. Methanol was distilled off while raising the temperature to 240 ° C., and after a predetermined amount of methanol was distilled off, 0.006 parts by weight of phosphoric acid and 0.0095 parts by weight of sodium dihydrogen dihydrogen dihydrate (14 ppm as sodium element). ) Was added, and the transesterification reaction was completed.

Then, the reaction product was transferred to the polymerization apparatus, and then the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less while gradually raising the temperature inside the polymerization apparatus to 290 ° C. to distill out ethylene glycol. .. When the melt viscosity equivalent to the intrinsic viscosity of 0.62 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 4.

The polyester resin composition obtained in Example 14 has good gelation rate and hydrolysis resistance, and has a small amount of linear oligomers generated, a cyclic oligomer content, and an increase, and thus an optical film or a release film. It had suitable physical properties.

(Comparative Example 8)
In an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C., a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times mol with respect to terephthalic acid) was gradually added. Was added to promote the esterification reaction. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was terminated when the reaction rate reached 95%.

105 parts by weight (equivalent to 100 parts by weight of PET) of the esterification reaction product at 255 ° C. thus obtained was transferred to a polymerization apparatus, and 0.02 parts by weight of manganese acetate tetrahydrate was transferred to an ethylene glycol solution (45 ppm as a manganese element). 0.012 parts by weight of diantimonate oxide was added to the ethylene glycol slurry. Then, 5 parts by weight of ethylene glycol (0.15 times by weight of the terephthal component) was additionally added to proceed with depolymerization, and then 0.006 parts by weight of phosphoric acid and 0.011 parts by weight of sodium dihydrogen phosphate dihydrate were added. A mixed ethylene glycol solution (16 ppm as sodium element) was added. Then, 0.1 part by weight of tetrabutylammonium bromide was added.

Then, while gradually raising the temperature inside the polymerization apparatus to 290 ° C., the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the melt viscosity equivalent to the intrinsic viscosity of 0.62 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 4.

Since the polyester resin composition obtained in Comparative Example 8 contained a large amount of manganese element, nitrogen element, and halogen element, the amount of ΔCOOH / COOH and linear oligomer generated increased.

(Comparative Example 9)
In an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C., a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times mol with respect to terephthalic acid) was gradually added. Was added to promote the esterification reaction. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was terminated when the reaction rate reached 95%.

105 parts by weight (equivalent to 100 parts by weight of PET) of the esterification reaction product at 255 ° C. thus obtained was transferred to a polymerization apparatus, and 0.02 parts by weight of manganese acetate tetrahydrate was transferred to an ethylene glycol solution (45 ppm as a manganese element). 0.012 parts by weight of diantimonate oxide was added to the ethylene glycol slurry. Then, 5 parts by weight of ethylene glycol (0.15 times by weight of the terephthal component) was additionally added to proceed with depolymerization, and then 0.006 parts by weight of phosphoric acid and 0.011 parts by weight of sodium dihydrogen phosphate dihydrate were added. A mixed ethylene glycol solution (16 ppm as sodium element) was added. Then, 0.1 part by weight of tetrabutylammonium methanesulfonate was added.

Then, while gradually raising the temperature inside the polymerization apparatus to 290 ° C., the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the melt viscosity equivalent to the intrinsic viscosity of 0.62 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 4.

Since the polyester resin composition obtained in Comparative Example 9 contained a large amount of manganese element, nitrogen element, and sulfur element, the amount of ΔCOOH / COOH and linear oligomer generated increased.

(Comparative Example 10)
In an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C., a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times mol with respect to terephthalic acid) was gradually added. Was added to promote the esterification reaction. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was terminated when the reaction rate reached 95%.

105 parts by weight (equivalent to 100 parts by weight of PET) of the esterification reaction product at 255 ° C. thus obtained was transferred to a polymerization apparatus, and 0.01 part by weight of manganese acetate tetrahydrate was transferred to an ethylene glycol solution (23 ppm as a manganese element). 0.012 parts by weight of diantimonate oxide was added to the ethylene glycol slurry. Then, 5 parts by weight of ethylene glycol (0.15 times by weight of the terephthal component) was additionally added to proceed with depolymerization, and then 0.006 parts by weight of phosphoric acid and 0.0095 parts by weight of sodium dihydrogen phosphate dihydrate were added. A mixed ethylene glycol solution (14 ppm as sodium element) was added. Then, 0.1 part by weight of tetrabutylammonium methanesulfonate was added.

Then, while gradually raising the temperature inside the polymerization apparatus to 290 ° C., the pressure inside the polymerization apparatus was gradually reduced from normal pressure to 133 Pa or less to distill out ethylene glycol. When the melt viscosity equivalent to the intrinsic viscosity of 0.62 is reached, the reaction is terminated, the inside of the reaction system is made normal pressure with nitrogen gas, and the pellet-like polymer is discharged and cut into cold water from the lower part of the polymerization apparatus in a strand shape. Got The obtained pellet-like polymer was dried at 160 ° C. for 6 hours and crystallized, and solid-phase polymerization was carried out at a vacuum degree of 40 Pa and 220 ° C. for 8 hours to obtain a polyester resin composition. The characteristics of the obtained polyester resin composition are shown in Table 4.
Since the polyester resin composition obtained in Comparative Example 10 contained a large amount of nitrogen element and sulfur element, the amount of ΔCOOH / COOH and linear oligomer generated increased.

Claims (6)

It is made of phosphoric acid and sodium phosphate salt, contains antimony element, satisfies the following formulas (I) to (IV) and (VII), and has a total content of 10 ppm of the element selected from nitrogen, sulfur and halogen. A polyethylene terephthalate resin composition, characterized in that it is less than .
Amount of linear oligomer generated ≤ 900ppm (I)
Cyclic trimer content ≤ 0.6 wt% (II)
5ppm ≤ Mn content ≤ 40ppm (III)
4ppm ≤ Na content ≤ 60ppm (IV)
17ppm ≤ P content ≤ 50ppm (VII)
The linear oligomer is the total amount of terephthalic acid, monohydroxyethyl terephthalate, and bishydroxyterephthalate, and the linear oligomer generation amount is polyethylene that has been allowed to stand in an environment of a temperature of 23 ° C. and a humidity of 50% for 24 hours or more. It is the amount of increase in linear oligomer when the terephthalate resin is heat-treated at 290 ° C. for 20 minutes under nitrogen. A polyester film comprising the polyethylene terephthalate resin composition of claim 1. A laminated polyester film having at least one layer made of the polyethylene terephthalate resin composition of claim 1. A laminated polyester film having a layer made of the polyethylene terephthalate resin composition of claim 1 on at least one surface. A polyester film for mold release, which comprises the polyethylene terephthalate resin composition of claim 1. When a dicarboxylic acid component or an ester-forming derivative component thereof and a diol component are subjected to an esterification reaction or an ester exchange reaction, and then melt polymerization and solid phase polymerization are carried out to produce a polyester, the IV (inherent viscosity) of the polyester is 0. Manganese compounds and antimony compounds were added at the stage of 4 or less, and phosphoric acid and sodium phosphate were added at the stage until the completion of the polycondensation reaction, and the contents thereof were the following formulas (V), (VI), and. A method for producing a polyethylene terephthalate resin composition, which satisfies (VIII) and has a total content of an element selected from nitrogen, sulfur and halogen of less than 10 ppm .
5ppm ≤ Mn content ≤ 40ppm (V)
4ppm ≤ Na content ≤ 60ppm (VI)
17ppm ≤ P content ≤ 50ppm (VIII)