JP2019085504A - Polyester resin composition and method for producing the same - Google Patents

Abstract

To provide a polyester resin composition that has excellent heat resistance, hydrolysis resistance, and optical properties, and reduces an amount of gel compositions and linear oligomers produced during melting molding and processing steps, and a rise in filtration pressure of a filter, and a method of producing the same.SOLUTION: A polyester resin composition satisfies the following formulae (I)-(IV): an amount of production of linear oligomers≤900 ppm (I); Sb content≤80 ppm (II); 5 ppm≤Mn content≤40 ppm (III); 4 ppm≤Na content≤40 ppm (IV).SELECTED DRAWING: None

Description

  The present invention is excellent in heat resistance, hydrolysis resistance and optical properties, and a gel composition produced in melt molding and processing steps, polyester resin composition with less generation of linear oligomers, and a rise in filtration pressure of a filter, and production thereof It relates to the method.

Polyester resins are excellent in mechanical properties, thermal properties, chemical resistance, electrical properties and moldability, and are used in various applications. Among polyester resins, polyethylene terephthalate (hereinafter referred to as PET) is widely used for applications requiring high definition such as optical films and release films because it is excellent in transparency and processability. . However, linear oligomers such as PET monomer components and low molecular weight oligomers (oligomer components) are generated and increased by the decomposition reaction of polyester resin, which volatilizes and scatters during molding and processing, and surface staining of molded articles may occur. is there. In addition, the scattering of the linear oligomers may cause process fouling, which causes the problem of deterioration of the quality of molded articles due to surface fouling and process fouling. In addition, when the polyester resin is thermally and oxidatively deteriorated during melt molding, a gel composition is generated, and process contamination such as die contamination becomes a problem. Furthermore, in film applications etc., this gel composition becomes a bright spot defect in the film and the quality is reduced. In recent years, optical films and mold release films are increasingly required to have high quality, 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 Document 1 discloses a technique for reducing the content of oligomers in a polyester resin and the amount of regenerated oligomers at melting by performing solid-phase polymerization and deactivation treatment. There is disclosed a technique for suppressing the scattering of linear oligomers by containing a liquid in polyester.

  Further, Patent Document 3 discloses a technique for controlling the gel composition by controlling the molar ratio of the amount of metal and the amount of phosphorus within a high range.

Unexamined-Japanese-Patent No. 2003-176347 International Publication No. 2016/167084 JP 2003-96280 A

As in the prior art described above, in the solid phase polymerization and deactivation treatment, only the cyclic oligomers contained in the polyester resin or generated during molding are reduced, and they are generated by different mechanisms such as thermal decomposition and hydrolysis during melting. Since the increase in linear oligomers was not effective, it was not possible to prevent surface contamination of the product and contamination in the processing process. In addition, when an ionic liquid is added to suppress scattering of linear oligomers, or when the molar ratio of metal to phosphorus is set to a high range for gel suppression, heat resistance and hydrolysis resistance are reduced. There was a problem called.

  The object of the present invention is to provide a polyester resin composition which is excellent in heat resistance, hydrolysis resistance, optical properties, gel composition generated in melt molding and processing steps, linear oligomer generation amount, and filter pressure increase. It is in providing the manufacturing method.

In order to solve the above-mentioned subject, the present invention has the following features.
(1) A polyester resin composition characterized by satisfying the following formulas (I) to (IV).
Linear oligomer generation amount ≦ 900 ppm (I)
Sb content ≦ 80 ppm (II)
5 ppm ≦ Mn content ≦ 40 ppm (III)
4 ppm ≦ Na content ≦ 40 ppm (IV)
(2) When the dicarboxylic acid component or the ester-forming derivative component thereof and the diol component are subjected to an esterification reaction or a transesterification reaction and then a polycondensation reaction to produce a polyester, the IV (inherent viscosity) of the polyester is 0.4 A manganese compound is added in the following stages, and phosphoric acid and an alkali metal phosphate are added in the stages up to the end of the polycondensation reaction, and the contents satisfy the following formulas (V) to (VII) The manufacturing method of the polyester resin composition characterized by the above.

Sb content ≦ 80 ppm (V)
5 ppm ≦ Mn content ≦ 40 ppm (VI)
4 ppm ≦ alkali metal content ≦ 40 ppm (VII)

  According to the present invention, a polyester resin composition which is excellent in heat resistance, hydrolysis resistance, optical properties, gel composition generated in melt molding and processing steps, linear oligomer generation amount, and filter pressure increase little. Can be provided.

The present invention will be described in detail below.
The polyester resin used in the present invention refers to a polyester resin obtained by polycondensation of 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 acids, linear aliphatic dicarboxylic acids and alicyclic dicarboxylic acids can be used. Among them, from the viewpoints of mechanical properties, heat resistance and hydrolysis resistance of the polyester resin composition, aromatic dicarboxylic acids and ester-forming derivatives thereof are preferable. In particular, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and ester forming derivative components thereof are preferable from the viewpoint of polymerizability and mechanical properties.

  Various diols can be used as the diol component in the present invention. For example, as aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol and the like, alicyclic diols Are various alicyclic diols such as cyclohexanedimethanol, cyclohexanediethanol, bisphenol A, bisphenol S, styrene glycol, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9'-bis ( Examples include aromatic cyclic diols such as 4-hydroxyphenyl) fluorene. Besides diols, polyfunctional alcohols such as trimethylolpropane and pentaerythritol can also be used.

Among these, diols having a boiling point of 230 ° C. or less 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 high in reactivity. Furthermore, ethylene glycol is particularly preferred from the viewpoint of mechanical properties.
In addition, another dicarboxylic acid component, a hydroxycarboxylic acid derivative, and a diol component may be copolymerized to such an extent that the range of the effect of the present invention is not impaired.

  The polyester resin composition of the present invention is required to have a linear oligomer generation amount of 900 ppm or less. The amount of generation of linear oligomers is an increase in the amount of linear oligomers when the polyester resin composition left to stand in an environment of temperature 23 ° C. and humidity 50% for 24 hours or more after heat treatment at 290 ° C. under nitrogen for 20 minutes. It is. In general, polyester resins are dried before melt processing to suppress hydrolysis. Since linear oligomers are also generated by hydrolysis of polyester resins, it is preferable to dry them before melt processing, but even if they are undried polyester resins, the drying process can be omitted if the generation of linear oligomers can be suppressed. It will be possible to reduce costs significantly. In the present invention, the heat resistance and hydrolysis resistance of the polyester resin are improved, so that the generation amount of linear oligomers can be dramatically reduced even in the state of high moisture content.

  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, specifically, a dicarboxylic acid component constituting the polyester resin, It refers to a chain reaction product formed by the reaction of the carboxyl group of dicarboxylic acid and the hydroxyl group of diol, and does not include cyclic oligomers such as cyclic trimers. Specifically, they are monoesters and diesters with dicarboxylic acid monomers and glycol components. This linear oligomer is easily sublimated or precipitated, and causes process stains and surface stains of the molded product in processing steps such as melt molding.

  Taking PET, which is a representative polyester resin, as an example, TPA (terephthalic acid), MHET (monohydroxyethyl terephthalate) and BHET (bishydroxyethyl terephthalate), which are the reaction products of terephthalic acid and ethylene glycol, are mentioned. The total amount of these linear oligomers needs to be 900 ppm or less, preferably 800 ppm or less, more preferably 700 ppm or less. By setting the generation amount of linear oligomers within the above range, it is possible to realize the reduction of process stains and surface stains caused by the linear oligomers, which is a problem during molding processing.

The polyester resin composition of the present invention is required to have an antimony content of 80 ppm or less as represented by the following formula (II).
Sb content ≦ 80 ppm (II)
Preferably it is 50 ppm or less, and 30 ppm or less is more preferable. The antimony compound is used as a polymerization catalyst for polyester, and the antimony element contained therein is easily reduced by the phosphorus compound and the like contained in the polyester resin composition to form antimony metal particles. Such antimony metal particles cause the color tone reduction and foreign matter of the polyester resin composition. By setting the antimony element content in the above-mentioned range, it is possible to prevent a decrease in optical characteristics such as a decrease in color tone, and an increase in filter pressure during melt molding caused by foreign matter.

  In the polyester resin composition of the present invention, the value of ΔCOOH / COOH, which is an indicator of hydrolysis resistance, is preferably 2.1 or less. This ΔCOOH is the amount of increase in COOH end groups when subjected to wet heat treatment at 155 ° C. for 4 hours under saturated steam, and as the value of ΔCOOH / COOH divided by the amount of COOH end groups before treatment is smaller, hydrolysis resistance The quality is good. If it is the said range, hydrolysis resistance is favorable and can suppress generation | occurrence | production of the linear oligomer resulting from a hydrolysis.

The polyester resin composition of the present invention is required to contain 5 ppm or more and 40 ppm or less of the manganese element as represented by the following formula (III).
5 ppm ≦ Mn content ≦ 40 ppm (III)
The lower limit is preferably 10 ppm or more. Also, the upper limit is preferably 30 ppm or less. By setting it as the said minimum or more, since the gel composition which generate | occur | produces at the time of melt molding can be suppressed, the fault of a molded object can be suppressed. The manganese element also contributes to the thermal decomposition, oxidative decomposition, and hydrolysis of the polyester because the catalytic activity is high even in heat treatment at a relatively low temperature below the polyester melting point such as a film stretching step. Therefore, it becomes possible to reduce the linear oligomer generation amount in a process process by satisfy | filling the amount of manganese elements below the said upper limit.

Moreover, the polyester resin composition of this invention needs to contain 4 ppm or more and 40 ppm or less of a sodium element, as it represents with following formula (IV).
4 ppm ≦ Na content ≦ 40 ppm (IV)
The lower limit is preferably 10 ppm or more. The upper limit is preferably 30 ppm or less. By setting it as the said range, hydrolysis resistance becomes favorable and it can suppress the linear oligomer generation | occurrence | production resulting from a hydrolysis.

  Moreover, it is preferable that the polyester resin composition of this invention contains 17 ppm or more and 70 ppm or less of phosphorus elements. 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. By setting it as the said range, the linear oligomer generation amount in a process process can be reduced.

  Furthermore, it is preferable that Na / P which is a molar ratio of content of a sodium element and a phosphorus element is 0.3 or more and 1.2 or less of the polyester resin composition of this invention. The lower limit is preferably 0.4 or more, and the upper limit is preferably 1.0 or less. By setting it as the said range, it becomes possible to provide hydrolysis resistance and can reduce the linear oligomer generation amount in a process process.

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

The polyester resin composition of the present invention preferably has a gelation ratio of 7 wt% or less when heat-treated at 300 ° C. for 6 hours in a nitrogen atmosphere with an oxygen concentration of 1%. More preferably, it is 5 wt% or less. By setting it as the said range, since the gel composition which generate | occur | produces at the time of melt molding can be suppressed, the fault of a molded object can be suppressed.
The polyester resin composition of the present invention preferably has a total light transmittance of greater than 80% in order to exhibit excellent optical properties. The total light transmittance is a value obtained by measurement according to the measurement method (10) in the examples described later.

  When the total light transmittance satisfies the above range, a molded article having excellent optical properties can be obtained. Therefore, it is suitable for an optical film etc. Further, more preferably, it is more than 83%, further preferably more than 87%.

  The polyester resin composition of the present invention achieves an optical characteristic in the above range by having 80 ppm or less of an antimony element causing color tone reduction, and is further selected from a titanium compound, an aluminum compound and a germanium compound as a polycondensation catalyst. By using the compound, higher optical properties are achieved.

Next, the method for producing the polyester resin composition of the present invention will be described.
The polyester resin composition of the present invention is an polyester IV (specifically, when the dicarboxylic acid component or its ester-forming derivative component is subjected to esterification reaction or transesterification reaction with a diol component and then polycondensation reaction to produce polyester. A manganese compound is added at a stage where the viscosity) is 0.4 or less, and phosphoric acid and an alkali metal salt of phosphoric acid are added at a stage up to the end of the polycondensation reaction, and the content thereof is the following formula (V) It can be obtained by satisfying VII).

Sb content ≦ 80 ppm (V)
5 ppm ≦ Mn content ≦ 40 ppm (VI)
4 ppm ≦ alkali metal content ≦ 40 ppm (VII)
In the method for producing a polyester resin composition of the present invention, the manganese compound needs to be added at a stage where the IV (inherent viscosity) of the polyester resin is 0.4 or less. By being added in the above range, the polymerization reactivity becomes good, and the dispersibility in the polyester resin also becomes good, so the transparency is enhanced. Among them, in the case of obtaining a polyester oligomer by transesterification, in order to allow the reaction to proceed more efficiently, it is preferable to add a manganese compound at the start of transesterification. When a polyester oligomer is obtained by the esterification reaction, it is preferable to add a manganese compound at a stage where the IV of the polyester resin is 0.4 or less from the end of the esterification reaction, and from the end of the esterification reaction It is more preferable to add it by the start of the condensation reaction. The esterification reaction is an autocatalytic reaction with an acid component such as terephthalic acid, so that the reaction proceeds sufficiently even without a catalyst, and if a catalyst is contained, by-products such as a dimer of a diol component increase. Conducting without using a catalyst and adding it before the viscosity of the polyester is increased, 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 content of the manganese compound in the polyester composition needs to satisfy the following formula (VI) as the amount of the added manganese compound.
5 ppm ≦ Mn content ≦ 40 ppm (VI)
The lower limit is preferably 10 ppm or more. Also, the upper limit is preferably 30 ppm or less. By setting it as the said minimum or more, since the gel composition which generate | occur | produces at the time of melt molding can be suppressed, the fault of a molded object can be suppressed. The manganese element also contributes to thermal decomposition, oxidative decomposition, and hydrolysis of the polyester resin because its catalytic activity is high even in heat treatment at a relatively low temperature below the polyester melting point such as a film stretching step. Therefore, it becomes possible to reduce the linear oligomer generation amount in a process process by satisfy | filling the amount of manganese elements below the said upper limit.

The manganese compound is not particularly limited, and manganese acetate, manganese nitrate, manganese sulfate, manganese chloride and the like can be mentioned, and manganese acetate is preferable in terms of solubility and catalytic activity.
The form of addition may be any of powder, slurry, and solution, and from the viewpoint of dispersibility, it is preferable to add as a solution. It is preferable to make the solvent at this time 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 in the stage until the polycondensation reaction is completed. More preferably, it is from the end of the ester exchange reaction and the esterification reaction to the start of the polycondensation reaction as the addition time of the phosphoric acid and the phosphoric acid alkali metal salt. By adding 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 addition amount of phosphoric acid is not particularly limited, but the lower limit of the addition amount is preferably 25 ppm or more as phosphorus element, more preferably 45 ppm or more. The upper limit of the addition amount is preferably 200 ppm or less, more preferably 150 ppm or less. By setting it as the said range, the thermal stability of a polyester resin composition can be made favorable, without causing a delay of superposition | polymerization. Since phosphoric acid is usually obtained 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 addition amount of the alkali metal phosphate is required to be 4 ppm or more and 40 ppm or less as the alkali metal element in the polyester composition. More preferably, the lower limit is 10 ppm or more. The upper limit is preferably 30 ppm or less. By setting it as the said range, hydrolysis resistance becomes favorable and it can suppress the linear oligomer generation | occurrence | production resulting from a hydrolysis.

  As an alkali metal phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium triphosphate, lithium dihydrogen phosphate, phosphoric acid Dilithium hydrogen and trilithium phosphate are mentioned. From the viewpoint of hydrolysis resistance, sodium salts are preferred, and sodium dihydrogen phosphate is particularly preferred. Further, a plurality of alkali metal phosphates may be used in combination.

  The form of addition may be any of powder, slurry, and solution, and from the viewpoint of dispersibility, it is preferable to add as a solution. It is preferable to make the solvent at this time 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.

  Furthermore, it is preferable to mix and add a solution of phosphoric acid and a phosphoric acid alkali metal salt. By mixing phosphoric acid and a phosphoric acid alkali metal salt and adding them as a buffer solution, better hydrolysis resistance is expressed, and it becomes possible to reduce the amount of linear oligomers generated in the processing step.

  Moreover, you may use together alkali metal compounds other than phosphoric acid alkali metal salt in the range with which the addition amount of the said alkali metal element is satisfy | filled. Specifically, lithium, sodium, potassium hydroxide, acetate, carbonate, nitrate, chloride and the like can be mentioned. Among these, by using potassium hydroxide in combination, the melting specific resistance of the polyester resin necessary for electrostatic application film forming can be reduced without increasing the linear oligomer generation amount, and the formability is improved.

  In the method for producing a polyester resin composition of the present invention, when carrying out via an esterification reaction, additional addition of a glycol component such as ethylene glycol is carried out after the esterification reaction until the addition of an alkali metal salt of phosphoric acid. It is preferable to do. More preferably, it is from the addition of the manganese compound to the addition of the alkali metal phosphate. The low molecular weight polymer of the polyester resin composition obtained by the esterification reaction has a higher degree of polymerization than the low molecular weight polymer obtained by the transesterification reaction, so that the alkali metal phosphate is difficult to disperse and foreign matter is likely to occur. Therefore, foreign matter formation can be suppressed by additionally adding a glycol component such as ethylene glycol and reducing the degree of polymerization by depolymerization. At this time, when a manganese compound is present, depolymerization can be performed more efficiently.

  It is preferable that the glycol component such as ethylene glycol to be additionally added is 0.05 times mol or more and 0.5 times mol or less with respect to the total acid components. More preferably, it is 0.1 times mole or more and 0.3 times mole or less. By setting it as the said range, foreign material formation of the alkali metal phosphate can be suppressed, without causing the delay of the superposition | polymerization time by the temperature fall in a superposition | polymerization system.

  In the method for producing a polyester resin composition of the present invention, the antimony content is required to be 80 ppm or less. It is preferably 50 ppm or less, more preferably 30 ppm or less. Antimony element is easily reduced by a phosphorus compound or the like contained in the polyester resin composition to form antimony metal particles. Such antimony metal particles cause a decrease in color tone of the polyester resin composition and foreign substances. By setting it as the said range, the fall of optical characteristics, such as a color tone fall, and the filter filtration pressure rise at the time of the melt molding caused by a foreign material can be prevented.

  Since the antimony compound is used as a polymerization catalyst for polyester, reducing the antimony element lowers the reactivity at the time of polyester polymerization. Therefore, it is preferable to use a polymerization catalyst other than the antimony compound. For example, a titanium compound, a germanium compound, and an aluminum compound are mentioned, By using these compounds, the optical characteristic of resin becomes favorable and the polyester resin composition suitable for an optical film use etc. is obtained. Examples of the titanium compound include, but are not limited to, alkoxytitanium compounds such as tetra-n-butoxytitanium, tetra-i-propoxytitanium, tetrakis (2-ethylhexyloxy) titanium and tetrastealenyloxytitanium. Examples of aluminum compounds include aluminum formate, aluminum acetate, aluminum propionate, aluminum oxalate, aluminum benzoate, and aluminum carboxylate compounds such as aluminum terephthalate, and aluminum chloride, aluminum hydroxide, aluminum nitrate, aluminum nitrate, aluminum carbonate, aluminum phosphate And inorganic aluminum compounds such as aluminum methoxides, aluminum methoxides, aluminum ethoxides, aluminum propoxides, and organoaluminum compounds such as aluminum butoxides, but not limited thereto. Germanium compounds include, but are not limited to, germanium dioxide and the like.

  The polycondensation catalysts such as the above-mentioned antimony compounds, titanium compounds, germanium compounds and aluminum compounds are preferably added at a stage where the IV (inherent viscosity) of the polyester resin is 0.4 or less. By being added in the above range, the polymerization reactivity becomes good, and the dispersibility in the polyester resin also becomes good, so the transparency is enhanced.

  In addition to the polycondensation catalyst, known transesterification catalysts and cocatalysts can be used. For example, as the transesterification catalyst and the co-catalyst, organic manganese compounds, organic magnesium compounds, organic calcium compounds, organic cobalt compounds, organic lithium compounds, organic potassium compounds and the like can be mentioned, but it is not limited thereto.

  The polyester resin composition of the present invention is an end blocking agent, an antioxidant, an ultraviolet light absorber, a flame retardant, a brightening 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 necessary.

Hereinafter, although the specific example of the manufacturing method of the polyester resin composition in this invention is given, it is not restrict | limited to this.
A slurry of terephthalic acid and ethylene glycol (1.15 moles per 1 mole of terephthalic acid) was gradually added to the esterification reactor charged with bishydroxyethyl terephthalate dissolved at 255 ° C using a snake pump to effect esterification. Let the reaction proceed. 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 thus obtained esterification reaction product at 255 ° C. is transferred to a polymerization apparatus, and a manganese compound and a polycondensation catalyst are added. Thereafter, ethylene glycol is additionally added, and phosphoric acid and phosphoric acid alkali metal salts are added. During these operations, it is preferable to maintain the temperature in the reaction system at 240 to 255 ° C. so that the esterified product does not solidify.

  Thereafter, while the temperature in the polymerization apparatus is gradually raised to 290 ° C., the pressure in the polymerization apparatus is gradually reduced from normal pressure to 133 Pa or less to distill ethylene glycol off. The reaction is terminated when a predetermined stirring torque is reached, the pressure in the reaction system is brought to normal pressure with nitrogen gas, and the molten polymer is discharged in cold water into strands and cut to obtain a polyester resin composition.

  The polyester resin composition of the present invention is excellent in heat resistance, hydrolysis resistance and optical properties, and the amount of gel composition and linear oligomers generated in melt molding and processing steps and the increase in filter pressure of the filter are small. Therefore, it can be used suitably for various uses, such as a film, a fiber, and a molded object, and it is possible to use especially the polyester film of this invention for high quality films, such as an optical film and release film for which high transparency is required. .

  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 of the polyester resin composition of the present invention on at least one surface is preferred. When the layer consisting of the polyester resin composition of the present invention is present on the film surface, the linear oligomer volatilization from the film surface is suppressed, so that the generation of the linear oligomer defect can be effectively suppressed.

  The present invention will be described in more detail with reference to the following examples. In addition, the physical-property value in an Example was measured by the following method. The method described below describes the measurement method in the case of the polyester resin composition single component of the present invention, but in the case of a molded product composed of a plurality of resins such as a laminated film, the resin of each layer is scraped etc. Isolate and analyze.

(1) Intrinsic viscosity of polyester resin composition (IV)
It measured at 25 degreeC using the o-chlorophenol solvent.

(2) Measured by the method of COOH end group amount Maurice of polyester resin composition. (Reference M. J. Maurice, F. Huizinga, Anal. Chem. Acta, 22, 363 (1960)).

(3) Antimony and manganese of the polyester resin composition, phosphorus, alkali metal element content Determination by atomic absorption method (manufactured by Hitachi, Ltd .: polarized Zeeman atomic absorption type 180-80, frame: acetylene air) The

(4) Elemental nitrogen content of polyester resin composition The polyester resin composition was freeze-ground and dried under reduced pressure at room temperature for 3 hours. Then, it quantified by ICP emission spectrometry (ND-100 type | mold by Mitsubishi Chemical Co., Ltd. product).

(5) Sulfur and Halogen Element Content of Polyester Resin Composition The polyester resin composition was freeze-ground and dried under reduced pressure for 3 hours at room temperature. Thereafter, quantification was carried out using a combustion ion chromatograph (ICA2000 manufactured by Toa DKK Co., Ltd.). At this time, less than 5 ppm was 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 Sprex CertiPerp), and weighed 0.5 g into a stainless beaker having a volume 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 oxygen / nitrogen concentration 1% gas flow (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 (3 GP 40, manufactured by Shibata Scientific 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 relative to the polyester weight (0.5 g) was determined from the increase in the weight of the filter before and after filtration to obtain the gelation ratio (%).

(7) Evaluation of hydrolysis resistance of polyester resin composition (ΔCOOH / COOH)
The polyester resin composition was subjected to wet heat treatment under saturated steam at 155 ° C. for 4 hours, and the amount of COOH end group increase (ΔCOOH = post-treatment COOH-pre-treatment COOH) was calculated by measuring the COOH end group weight before and after treatment. . The hydrolysis resistance was evaluated by dividing the value of ΔCOOH by the amount of COOH end group before treatment.
The following heat treatment apparatus was used as the treatment apparatus.
PRESSER COOKER 306 SIII (manufactured by HIRAYAMA Manufacturing Co., Ltd.).

(8) Linear Oligomer Generation Amount of Polyester Resin Composition Measure 0.1 g of the polyester resin composition (water content 2500 ppm) which was allowed to stand for 24 hours or more under the environment of temperature 23 ° C. and humidity 50%. Under the atmosphere, melting 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 further add 40 mL of methanol I added it gradually. Then, 0.5 mL of DMF (N, N-dimethylformamide) is added to the residue obtained by concentrating and drying the solution obtained by filtering through a paper filter (No. 2 made by ADVANTEC), and then dissolved and dispersed, Ethanol was added to make up to 5 mL. The solution filtered through a PTFE membrane filter with a pore size of 0.45 μm was used as a sample solution. The content of linear oligomers (TPA, MHET, BHET) in the polyester resin composition after melt processing was measured by analyzing the obtained sample solution by LC / UV. At this time, the amount of generation of linear oligomers was determined by calculating the difference between the content of linear oligomers before and after melt processing (content after melt processing-content before melt processing).

(9) Preparation of Press Sheet The polyester resin composition was vacuum dried at 150 ° C. for 8 hours, and a press sheet heated to 290 ° C. was used to form a press sheet having a thickness of 100 μm.

(10) Total Light Transmittance Based on JIS-K-7361-1, the total light transmittance of the press sheet prepared in the above (9) was measured using a single beam type haze meter.

(11) Filterability Test The polyester resin composition was vacuum dried at 145 ° C. for 7.5 hours, and then the polyester resin composition was extruded by an extruder equipped with a single screw (temperature 300 ° C., discharge amount 10 g / min). The filtration pressure applied to the filter (φ 24.5 mm, opening 5 μm) was measured. The filtration pressure at the start of discharge was P ₀ (MPa), the filtration pressure 6 hours after discharge was P ₁ (MPa), and the increase in filtration pressure was judged at P ₁ -P ₀ .

◎: P ₁ −P ₀ ≦ 0.2
○: 0.2 <P ₁ −P ₀ ≦ 0.3
_{×: 0.3 <P 1 -P 0} .

Example 1
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate A solution of 0.007 parts by weight of n-butoxytitanium in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin composition obtained in Example 1 is excellent in the gelation rate, hydrolysis resistance, optical properties, and the amount of linear oligomers generated and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Example 2)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate, water A solution of 0.015 parts by weight of aluminum oxide in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin composition obtained in Example 2 is excellent in the gelation rate, hydrolysis resistance, optical properties, and the amount of linear oligomers generated, and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Example 3)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate A solution of 0.02 parts by weight of germanium in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin composition obtained in Example 3 is excellent in the gelation rate, hydrolysis resistance, optical properties, and the generation amount of linear oligomers, and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Example 4)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate An ethylene glycol slurry of 0.0096 parts by weight diantimony oxide was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin composition obtained in Example 4 is excellent in the gelation rate, hydrolysis resistance, optical properties, and the generation amount of linear oligomers, and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Examples 5, 6 and Comparative Example 1)
A polyester resin composition was obtained in the same manner as in Example 4 except that the amount of diantimony trioxide added was changed as shown in Table 1. The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin compositions obtained in Examples 5 and 6 are excellent in the gelation ratio, hydrolysis resistance, optical properties, and the amount of linear oligomers generated and the increase in filtration pressure are also small. It had physical properties suitable for the mold film.

  Since the polyester resin composition obtained in Comparative Example 1 had a high antimony content, a decrease in optical properties and a rise in filtration pressure were observed.

(Examples 7 to 10, Comparative Examples 2 and 3)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amount of the manganese compound was changed as shown in Table 2. The properties of the obtained polyester resin composition are shown in Table 2.

  The polyester resin compositions obtained in Examples 7 to 10 have good gelation rate, hydrolysis resistance and optical properties, and have little generation of linear oligomers and a small increase in filtration pressure. It had physical properties suitable for the mold film.

  Since the polyester resin composition obtained in Comparative Example 2 had a high content of manganese element, ΔCOOH / COOH and the amount of linear oligomers generated increased.

  Since the polyester resin composition obtained in Comparative Example 3 did not contain a manganese element, the gelation ratio, ΔCOOH / COOH, and the amount of linear oligomers generated increased.

(Examples 11 to 14, Comparative Examples 4 and 5)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amount of the alkali metal phosphate was changed as shown in Table 3. The properties of the obtained polyester resin composition are shown in Table 3.

The polyester resin compositions obtained in Examples 11 to 14 have good gelation rate, hydrolysis resistance, and optical properties, and the amount of linear oligomers generated and the increase in filtration pressure are also small. It had physical properties suitable for the mold film.
In the polyester resin composition obtained in Comparative Example 4, since the alkali metal phosphate was not added, ΔCOOH / COOH and the amount of linear oligomers generated increased.
Since the polyester resin composition obtained in Comparative Example 5 had a large amount of addition of the alkali metal phosphate, ΔCOOH / COOH and the amount of linear oligomers generated increased.

(Examples 15 to 17 and Comparative Example 6)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amount of phosphoric acid was changed as shown in Table 4. The properties of the obtained polyester resin composition are shown in Table 4.

The polyester resin compositions obtained in Examples 15 to 17 have good gelation rate, hydrolysis resistance, optical properties, and a small amount of linear oligomer generation and a small increase in filtration pressure. It had physical properties suitable for the mold film.
In the polyester resin composition obtained in Comparative Example 6, since no phosphoric acid was added, ΔCOOH / COOH and the amount of linear oligomers generated increased.

(Example 18)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate A solution of 0.007 parts by weight of n-butoxy titanium in ethylene glycol and a solution of 0.0008 parts by weight of potassium hydroxide in ethylene glycol were added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 5.

  The polyester resin composition obtained in Example 18 is excellent in the gelation ratio, hydrolysis resistance, optical properties, and the amount of linear oligomers generated, and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Example 19)
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) were respectively weighed and charged in a transesterification reactor. After the contents were dissolved at 150 ° C., an ethylene glycol solution (40 ppm as manganese element) of 0.018 parts by weight of manganese acetate tetrahydrate was added and stirred. Methanol is distilled while raising the temperature to 240 ° C., and a predetermined amount of methanol is distilled, and then 0.006 parts by weight of phosphoric acid and 0.0095 parts by weight of sodium dihydrogen phosphate dihydrate (14 ppm as a sodium element) The mixed ethylene glycol solution of) was added to complete the transesterification reaction.
Thereafter, the reaction product is transferred to the polymerization apparatus, and then an ethylene glycol solution of 0.007 parts by weight of tetra-n-butoxytitanium is added, and the pressure in the polymerization apparatus is gradually raised while raising the temperature in the polymerization apparatus to 290 ° C. The ethylene glycol was distilled off by gradually reducing the pressure from normal pressure to 133 Pa or less. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 5.
The polyester resin composition obtained in Example 19 is excellent in the gelation rate, hydrolysis resistance, optical properties, and the amount of linear oligomers generated, and the increase in filtration pressure is also small, so it can be used as an optical film or a release film. It had suitable physical properties.

(Comparative example 7)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (45 ppm as manganese element) of 0.02 parts by weight of manganese acetate tetrahydrate A solution of 0.007 parts by weight of n-butoxytitanium in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (16 ppm as sodium element) was added. Thereafter, 0.1 parts by weight of tetrabutylammonium bromide was added.

  Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 5.

  Since the polyester resin composition obtained in Comparative Example 7 contained a large amount of manganese element, nitrogen element and halogen element, the gelation ratio and ΔCOOH / COOH increased, and the linear oligomer generation amount increased. .

(Comparative example 8)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (45 ppm as manganese element) of 0.02 parts by weight of manganese acetate tetrahydrate A solution of 0.007 parts by weight of n-butoxytitanium in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (16 ppm as sodium element) was added. Thereafter, 0.1 parts by weight of tetrabutylammonium methanesulfonate was added.

Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 5.
Since the polyester resin composition obtained in Comparative Example 8 contained a large amount of manganese element, nitrogen element and sulfur element, the gelation ratio and ΔCOOH / COOH increased, and the linear oligomer generation amount increased. .

(Comparative example 9)
A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount of terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate dissolved at 255 ° C. The esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 255 ° C., and the esterification reaction was ended 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 is transferred to a polymerization apparatus, and an ethylene glycol solution (23 ppm as manganese element) of 0.01 parts by weight of manganese acetate tetrahydrate A solution of 0.007 parts by weight of n-butoxytitanium in ethylene glycol was added. Thereafter, 5 parts by weight of ethylene glycol (0.15 times the molar amount of the terephthal component) is further 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 A mixed ethylene glycol solution (14 ppm as sodium element) was added. Thereafter, 0.1 parts by weight of tetrabutylammonium methanesulfonate was added.

Thereafter, while the temperature in the polymerization apparatus was gradually raised to 290 ° C., the pressure in the polymerization apparatus was gradually reduced from atmospheric pressure to 133 Pa or less to distill ethylene glycol. When reaching a melt viscosity equivalent to an intrinsic viscosity of 0.62, the reaction is terminated, the inside of the reaction system is brought to normal pressure with nitrogen gas, and it is discharged in cold water from the lower part of the polymerization apparatus into strands and cut. I got a thing. The properties of the obtained polyester resin composition are shown in Table 5.
Since the polyester resin composition obtained in Comparative Example 9 contained a large amount of nitrogen and sulfur elements, the gelation ratio and ΔCOOH / COOH increased, and the linear oligomer generation amount increased.

Claims (12)

The polyester resin composition characterized by satisfy | filling following formula (I)-(IV).
Linear oligomer generation amount ≦ 900 ppm (I)
Sb content ≦ 80 ppm (II)
5 ppm ≦ Mn content ≦ 40 ppm (III)
4 ppm ≦ Na content ≦ 40 ppm (IV) The polyester resin composition according to claim 1, wherein the total content of elements selected from nitrogen, sulfur and halogen is less than 10 ppm. The polyester resin composition according to claim 1 or 2, wherein the gelation rate is 7 wt% or less. The polyester resin composition according to any one of claims 1 to 3, wherein the total light transmittance is 80% or more. The polyester resin composition according to any one of claims 1 to 4, wherein the polyester is polyethylene terephthalate. A polyester film comprising the polyester resin composition of claim 1. A laminated polyester film comprising at least one layer comprising the polyester resin composition of claim 1. A laminated polyester film having a layer comprising the polyester resin composition of claim 1 on at least one surface. A polyester film for mold release comprising the polyester resin composition of claim 1. When the dicarboxylic acid component or its ester-forming derivative component is subjected to an esterification reaction or transesterification reaction with a diol component and then a polycondensation reaction to produce a polyester, the stage of IV (intrinsic viscosity) of the polyester is 0.4 or less And a manganese compound is added, and phosphoric acid and an alkali metal salt of phosphoric acid are added at the stage until the end of the polycondensation reaction, and the content thereof satisfies the following formulas (V) to (VII). Method for producing a polyester resin composition
Sb content ≦ 80 ppm (V)
5 ppm ≦ Mn content ≦ 40 ppm (VI)
4 ppm ≦ alkali metal content ≦ 40 ppm (VII) The method for producing a polyester resin composition according to claim 10, wherein the alkali metal phosphate is a phosphate sodium salt. The method for producing a polyester resin composition according to claim 10 or 11, wherein the polyester is polyethylene terephthalate.