JP2016141791A - Copolymerized polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolymerized polyester resin composition amorphous, satisfactory in transparency, reduced in the content of a cyclic trimer and the regeneration amount of the cyclic trimer upon melting and suitable for film molding.SOLUTION: Provided is a polyester resin composition made of terephthalic acid or dicarboxylic acid components essentially consisting of the same and ethylene glycol or a diol component essentially consisting of the same, in which, as the dicarboxylic acid components, isophthalic acid is included by 20 to 40 mol% and an antimony element is included by 150 to 250 ppm, a haze is 0.5 to 1.0% and a fusion rate is 10% lower. In the copolymerized polyester resin composition, inherent viscosity is 0.50 to 0.70 dl/g, and the content of the cyclic trimer is 0.35 to 0.45 wt.%.SELECTED DRAWING: None

Description

  The present invention relates to a copolymerized polyester resin composition and a method for producing the same. More specifically, a copolymerized polyester resin having a non-crystalline and cyclic trimer content and a small amount of recycled cyclic trimer upon melting, excellent transparency (haze), and an intrinsic viscosity suitable for film molding. The present invention relates to a composition and a method for producing the composition.

Polyester, especially polyethylene terephthalate, is widely used for fibers, films and bottles due to its excellent properties.
The industrial production method of the copolyester resin composition includes direct polymerization of terephthalic acid and ethylene glycol, followed by polycondensation, and transesterification of dimethyl terephthalate and ethylene glycol. Later, a transesterification method in which polycondensation is performed is widely adopted.

  Conventionally, a polarizing plate used in a liquid crystal display is generally composed of a protective film / polarizing film / protective film, or a protective film / polarizing film / retardation film, and has a high transparency as a protective film of a conventional polarizing plate. TAC (triacetyl cellulose) films have been used in many cases due to characteristics such as optical properties, optical isotropy, and a small amount of foreign matter. However, with the expansion of smartphones and tablets, the trend of thinning has been followed year by year. The deterioration of the handling property of the TAC film due to the thinning and the high cost of the TAC film are problems.

Many studies have been conducted to replace the TAC film with a copolyester film for the above problems (Patent Document 1).
Isophthalic acid copolyesters have a lower melting point than homopolyesters, are difficult to crystallize, and have the potential of causing degradation and degradation. In other words, the isophthalic acid copolymer polyester chip obtained by the melt polycondensation reaction is chip-handling, for example, drying, solid-phase polymerization, when the film is fused to the machine wall during film formation, hydrolysis, thermal decomposition, oxidative decomposition, etc. There is a problem that causes degradation and decomposition of the chip, and causes coloration of the chip and a decrease in intrinsic viscosity.

A method for producing a copolyester resin composition (Patent Document 2) has been proposed for the above problems. The copolyester resin composition obtained by this method has an isophthalic acid copolymerization amount of 20 mol%. The copolymer polyester resin composition obtained by this method has a problem that the chip is subsequently fused to the machine wall and the transparency is inferior when the content is below 20 mol%.
Another document proposes a method for producing a copolymerized polyethylene terephthalate (Patent Document 3), but the problem is that the amount of isophthalic acid copolymerization is 10 mol% or less, and the intrinsic viscosity is low, making it unsuitable for film molding. is there.

JP 2013-200355 A JP-A-7-108528 JP 2006-328251 A

  The object of the present invention is to solve the above-mentioned conventional problems, and is excellent in transparency (haze), which has become increasingly demanding properties in recent years with transparent optical films, etc., and the content of cyclic trimer and at the time of melting An object of the present invention is to provide a copolymerized polyester resin composition that has a small amount of regenerated cyclic trimer, has an intrinsic viscosity suitable for film molding, and does not cause fusion during drying, and a method for producing the same.

An object of the present invention described above is a polyester resin composition comprising terephthalic acid or a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of ethylene glycol or a diol component mainly composed of terephthalic acid, wherein 20 to This can be achieved with a copolymerized polyester resin composition characterized by containing 40 mol%, 150 to 250 ppm of antimony element, a haze of 0.5 to 1.0%, and a fusion rate of 10% or less.

The copolymerized polyester resin composition of the present invention has a low content of the cyclic trimer and a regenerated amount of the cyclic trimer at the time of melting, is excellent in amorphousness and transparency (low haze), and is suitable for film molding. A copolyester resin composition having a high intrinsic viscosity and no occurrence of fusion between chips during heat treatment is provided.

In the polyester of the present invention, the main dicarboxylic acid component is a terephthalic acid unit, the main glycol component is an ethylene glycol unit, and isophthalic acid is used as a constituent component of 20 to 40 mol% as the dicarboxylic acid component. Preferably, the isophthalic acid component is 22 to 38 mol%, more preferably 25 to 35 mol% from the viewpoint of film forming property, amorphous property, and transparency. Moreover, if it is 20 mol% or less, dicarboxylic acid components other than the said dicarboxylic acid can be included.

Examples of glycols other than ethylene glycol include propylene glycol, butanediol, diethylene glycol, hexamethylene glycol, p-xylene glycol, 1,4-cyclohexadimethanol, and bisphenol. A diol component other than ethylene glycol can be included as a diol unit if it is 20 mol% or less.
Furthermore, a polyester obtained by copolymerizing a trifunctional or higher polyfunctional compound may be used as long as the thermoplasticity is not impaired.

  In the polyester resin composition of the present invention, the content of antimony element is 150 to 250 ppm, preferably 180 to 230 ppm. When the content is 150 ppm or more, the heat resistance during melting of the polyester resin composition can be improved. In addition, the color tone does not turn yellow during melt film formation. If it is 250 ppm or less, the antimony element in the polyester resin composition is not insolubilized at the time of film formation, so that transparency can be maintained well.

  Here, as for the polyester resin composition of this invention, the haze measured with the haze computer is 0.5 to 1.0%, Preferably it is 0.6 to 0.9%. The smaller the haze, the better. If the haze is 0.5% or more, it can be said that the transparency is sufficient. Moreover, if the haze is 1.0% or less, it can be said that the transparency during film formation is good.

  The polyester resin composition in the present invention is required to have a fusion rate of 10% or less, and more preferably 5% or less. When the fusion rate is 10% or less, the chip is not fused to the apparatus wall when drying, solid phase polymerization, or film formation, and the regeneration of the cyclic trimer at the time of melting is suppressed. The transparency is also good, which is preferable.

  The polyester resin composition in the present invention preferably has an intrinsic viscosity in the range of 0.50 to 0.70, and more preferably in the range of 0.55 to 0.65. When it is 0.50 or more, there is no process trouble at the time of film forming, and the mechanical properties of the obtained film are further improved. Moreover, if it is 0.70 or less, the temperature rise due to shear heat generation during melt extrusion can be reduced, and the cyclic trimer regeneration during melting is suppressed, and the thermal deterioration of the polymer is suppressed, and the mechanical properties during film forming are suppressed. There is also an effect of improving the.

  In the polyester resin composition of the present invention, the cyclic trimer content is preferably 0.35 to 0.45 wt%, and more preferably 0.40 wt% or less. When the content of the cyclic trimer is 0.45 wt% or less, the cyclic trimer is hardly deposited on the surface of the film at the time of film forming or in the film processing step. The lower limit of the content of the cyclic trimer is not particularly limited, but in the present invention, when it is 0.10 wt% or more, the time required for solid phase polymerization to reduce the cyclic trimer is efficient. And the load at the time of melt extrusion is reduced in terms of intrinsic viscosity.

  The polyester resin composition according to the present invention preferably has a cyclic trimer regeneration rate of 0.010 wt% / min or less when melted at 300 ° C. When it is 0.010 wt% or less, precipitation of the cyclic trimer during film forming or in the film processing step can be suppressed, which is preferable. The lower limit of the cyclic trimer regeneration speed is not particularly limited, but is 0.002 wt% or more in the present invention. When the content is 0.002 wt% or more, it is not necessary to extremely reduce the content of the antimony element. For this reason, the melt polymerization or solid phase polymerization of the polyester resin composition can be smoothly advanced, and the productivity is improved.

A conventionally well-known manufacturing method can be employ | adopted for the copolyester resin composition which is a precursor of this invention.
For example, bis-β-hydroxyethyl terephthalate (hereinafter referred to as BHT), which is a reaction product of 75 mol% terephthalic acid, 25 mol% isophthalic acid and ethylene glycol, is stored in a molten state at 255 ° C. in advance, and terephthalic acid and ethylene glycol are further stored. A slurry consisting of the above and a slurry consisting of isophthalic acid and ethylene glycol are prepared in separate tanks, and water is distilled off and esterified while maintaining the temperature of the reaction tank and supplying a constant amount. After 4 to 5 hours from the start of the reaction, the esterification is completed, the reaction product BHT is transferred to a polycondensation reaction tank, and potassium hydroxide, antimony trioxide and other additives are added. Thereafter, the pressure is reduced until a high vacuum is achieved, and the polycondensation reaction is performed by heating and raising the temperature to about 290 ° C. until the target intrinsic viscosity is reached.

  When the potassium hydroxide and the antimony compound are added before the polycondensation reaction, the decomposition reaction of the resulting polyester resin composition can be suppressed, and the polycondensation reaction can proceed efficiently. Further, it is preferable because the aggregation (antimony metal) and the like are less and the transparency (haze) is improved.

The alkali metal compound is preferably added as an ethylene glycol solution from the viewpoint of improving the heat resistance of the resulting polyester resin composition.
Further, it is preferable to add the antimony compound as an ethylene glycol solution from the viewpoint of preventing the formation of a coarse product due to aggregation of the antimony compound in the polycondensation reaction system and, as a result, improving the transparency (haze).

  After completion of the reaction, the polymer is discharged and cooled in cold water from a polymer discharge nozzle provided at the bottom of the polycondensation reaction tank, and pelletized by a cutter.

(Contact process)
In the present invention, the copolyester resin composition obtained by the melt polycondensation and pelletized is brought into contact with a thermal diol component to extract the antimony element in the copolyester pellet. The contact is performed until the intrinsic viscosity of the copolyester resin composition becomes 0.50 to 0.70 dl / g.

  The diol component is a diol component having a boiling point of 190 ° C. or higher, preferably ethylene glycol, diethylene glycol, or triethylene glycol. More preferred is ethylene glycol.

  The contact temperature between the copolymerized polyester resin composition and the diol component is 100 to 200 ° C, and preferably 140 to 190 ° C in the crystallization region of the polyester. The contact time is 30 to 200 minutes, preferably 45 to 120 minutes, and more preferably 60 to 90 minutes. By contacting with a thermal diol component in these ranges, the antimony element in the polyester is extracted, and the fusion rate at which fusion does not occur during drying is 10% or less.

(Separation process)
It is preferable to provide the separation process which isolate | separates the obtained copolyester resin composition and the liquid phase which consists of a diol component after a contact process. Separation may be performed by any method as long as the solid copolymer polyester resin composition can be separated, and examples thereof include filtration, centrifugation, and decantation. For example, the dispersion of the copolyester resin composition obtained by the contacting step can be carried out by passing it through a 5 to 100 mesh filter. Here, the separated diol component is preferably recycled by distillation or the like.

(Washing / dehydration process)
After the separation step, it is preferable to wash the obtained copolymer polyester resin composition and perform a dehydration step.

  In this step, it is preferable to wash the copolymer polyester resin composition to which the diol component is adhered with water. The washing water is preferably washed with water at room temperature (preferably 10 to 40 ° C.), and the obtained copolymer polyester resin composition is preferably brought to room temperature.

The polyethylene terephthalate resin composition of the present invention can be formed into a polyester film by the following method.
For example, after the polyethylene terephthalate resin composition is vacuum dried, it is supplied to an extruder, melted at 260 to 300 ° C., extruded into a sheet form from a T-shaped die, and a surface temperature of 10 to 60 using an electrostatic application casting method. It is wound around a mirror surface casting drum at 0 ° C. and cooled and solidified to produce an unstretched polyester film.

  The unstretched film is stretched 2.5 to 5 times in the machine direction between rolls heated to 70 to 120 ° C. At least one surface of the film may be subjected to a corona discharge treatment to apply a coating liquid or the like. Subsequently, the film was stretched 2.5 to 5 times in the width direction in a hot air zone continuously heated to 70 to 150 ° C., then led to a heat treatment zone of 200 to 240 ° C., and subjected to a heat treatment of 5 to 40 seconds, 100 Crystal orientation is completed through a cooling zone of ~ 200 ° C. Moreover, you may perform a 3-12% relaxation process in the width direction or a longitudinal direction as needed during the said heat processing.

The polyethylene terephthalate resin composition obtained by the present invention has a low content of cyclic trimer and a small amount of cyclic trimer when melted, good color tone, excellent transparency (haze), and film molding. Since it has a suitable intrinsic viscosity, it can be suitably used for films for IT-related applications such as display devices for liquid crystal displays and magnetic recording materials.
Moreover, the polarizer protective film using the copolyester resin composition in the present invention has good retardation from the point of amorphousness.

The present invention will be described more specifically with reference to the following examples.
In addition, the measuring method of a physical property and the evaluation method of an effect were performed in accordance with the following method.

(1) Haze (transparency) of copolymerized polyester resin composition
0.5 g of the copolyester resin composition was dissolved in 20 ml of a mixed solvent of phenol / ethane tetrachloride (6/4 weight ratio) by stirring at 100 ° C. for 60 minutes, and cooled to room temperature. It put into the cell and measured with the HEZ computer (HGM-2DP) made from Suga Test Instruments.

(2) Fusing rate and fusing property of copolymerized polyester resin composition Chip-metal fusing test The smooth surface of SUS is 1 to 1.5 mm thick and the surface smoothness (JISP 8119) is 100 seconds or more. Use a metal version of 50 copolyester resin compositions pelletized into a cylindrical shape having a diameter of 2.55 mm and a height of 3.83 mm are aligned on a metal plate with the side of the pellet facing down and the pellets separated by 1 mm or more. Each metal plate is placed in a heating oven at a constant temperature of 150 ° C. and heated for 30 minutes. After heating, the metal plate is taken out and the metal plate is slowly tilted to 90 °. Count the number of pellets that fused to the metal plate and did not fall. The fusion rate (%) is calculated by the following formula.
Fusing rate (%) = number of fusion pellets not falling ÷ total number of pellets × 100
<Fusion criteria>
○: Fusion rate of 10% or less ×: Fusion rate of over 10%

(3) An antimony element amount fluorescent X-ray elemental analyzer (manufactured by Horiba, Ltd., MESA-500W type) of a copolyester resin composition was used to determine the fluorescent X-ray intensity for each element and prepared in advance. It was determined from a calibration curve.

(4) Intrinsic viscosity of copolymerized polyester resin composition The sample pellet of the copolymerized polyester resin composition was heated and dissolved in o-chlorophenol, and then measured at 25 ° C using an Ubbelohde viscometer.

(5) The sample pellet of the cyclic trimer copolymer polyester resin composition of the copolymer polyester resin composition is dissolved in o-chlorophenol, and an internal standard is added. Further, methanol was added to precipitate the polymer, and the supernatant was collected by centrifugation and quantified using a liquid chromatograph.

(6) Regeneration rate of cyclic trimer of copolymerized polyester resin composition Sample pellets of polyethylene terephthalate resin composition were vacuum-dried at 175 ° C for 7.5 hours, and then heated and dissolved at 300 ° C for 30 minutes in a nitrogen atmosphere. Next, the sample is collected by returning to normal temperature and solidifying. The cyclic trimer content (A) of the sample before heat dissolution treatment and the cyclic trimer content (B) of the sample after heat dissolution treatment are quantified, and the regeneration rate of the cyclic trimer (C) from the following equation: Was calculated.

  C (wt% / min) = (BA) / 30.

(7) Precipitation of cyclic trimer The film was cut into a size of 5 cm × 5 cm, heated in a hot air dryer at 150 ° C. for 60 minutes, and then observed on the surface of the film at 1,000 times with a scanning electron microscope. The number of precipitates of the cyclic trimer on the film surface that was arbitrarily selected and photographed was counted. As for the precipitation property of the cyclic trimer, less than 5 precipitates were good (◯), 5 to less than 10 passed (△), and 10 or more rejected (x).

[Example 1]
46.4 parts by weight of bis-β-hydroxyethyl terephthalate (hereinafter referred to as BHT), which is a reaction product of terephthalic acid and ethylene glycol consisting of 30.8 parts by weight of terephthalic acid and 10.8 parts by weight of isophthalic acid, was previously added at 255 ° C. Store in a molten state, and prepare a separate slurry containing 35.1 parts by weight of terephthalic acid, 11.3 parts by weight of isophthalic acid, and 19.5 parts by weight of ethylene glycol. While feeding, water was distilled to cause esterification. After 4 hours and 40 minutes from the start of the reaction, the esterification was completed, and BHT as this reaction product was transferred to a polycondensation reaction tank, and 0.0211 parts by weight of triethylphosphonoacetate was added. Next, 0.06 parts by weight of magnesium acetate, 0.0004 parts by weight of potassium hydroxide, and 0.04 parts by weight of antimony trioxide are added, and the pressure is reduced to a high vacuum in 40 minutes. Then, a polycondensation reaction was carried out until the target intrinsic viscosity was reached. After completion of the reaction, strands were discharged into cold water from a base at the bottom of the polycondensation reaction tank, and cylindrical pellets having a diameter of 2.55 mm and a height of 3.83 mm were formed by an extrusion cutter.

  The quality of the obtained copolymerized polyester resin composition is as follows: intrinsic viscosity is 0.75 dl / g, color tone b value is 5.5, haze is 2.4%, carboxyl end group is 27.6 eq / ton, antimony content Was 305 ppm, the cyclic trimer content was 0.47 wt%, and the fusion rate was 50%.

100 g of the copolymerized polyester resin composition pellets were placed in 300 g of ethylene glycol heated to 150 ° C., stirred at normal pressure for 60 minutes, and brought into contact with ethylene glycol.
After the contact treatment, the liquid phase mainly composed of the copolymerized polyester resin composition and ethylene glycol was filtered off using a 10-mesh filter.
The copolymerized polyester resin composition separated by filtration was washed with water and then blown and dried at room temperature under pressure.
The quality of the obtained copolyester resin composition was as follows: intrinsic viscosity 0.57 dl / g, haze 0.7%, antimony content 190 ppm, cyclic trimer content 0.39 wt% The rate was 5%, which was good. The results are shown in Table 2.

(Film forming)
The copolyester resin composition after the contact treatment is dried at 150 ° C. for 3 hours, supplied to an extruder, melt-extruded at 285 ° C., cast on a 20 ° C. cast drum applied electrostatically, and unstretched sheet Got. This unstretched sheet was stretched 3.1 times in the longitudinal direction by a stretching roll heated to 90 ° C, then stretched 3.7 times in the width direction at 120 ° C by a tenter type stretching machine, and then heat-set at 230 ° C. And wound up on a roll. The moldability of the film was good, and the precipitation property of the cyclic trimer of the obtained film was good.

[Example 2]
The same procedure as in Example 1 was performed except that the content of isophthalic acid was changed to Table 1. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.55 dl / g, haze is 0.6%, antimony content is 185 ppm, cyclic trimer content is 0.37 wt%, fusion rate Was 7% and was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 3]
The same procedure as in Example 1 was performed except that the content of isophthalic acid was changed to Table 1. The quality of the obtained copolyester resin composition is intrinsic viscosity 0.60 dl / g, haze 1.0%, antimony content 230 ppm, cyclic trimer content 0.45 wt%, fusion rate Was 4%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 4]
The same procedure as in Example 1 was performed except that the content of isophthalic acid was changed to Table 1. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.51 dl / g, haze is 0.6%, antimony content is 180 ppm, cyclic trimer content is 0.35 wt%, fusion rate Was 8%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 5]
A diol component to be contacted was triethylene glycol, and the same procedure as in Example 1 was performed except that the contact temperature was 200 ° C. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.51 dl / g, haze is 0.5%, antimony content is 180 ppm, cyclic trimer content is 0.35 wt%, fusion rate Was 3%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 6]
The same procedure as in Example 1 was performed except that the contact temperature was changed to Table 1. The quality of the obtained copolyester resin composition is intrinsic viscosity 0.60 dl / g, haze 1.0%, antimony content 230 ppm, cyclic trimer content 0.45 wt%, fusion rate Was 8%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 7]
The same method as in Example 1 was performed except that the contact time was changed to Table 1. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.51 dl / g, haze is 0.5%, antimony content is 180 ppm, cyclic trimer content is 0.35 wt%, fusion rate Was 2%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 8]
The same method as in Example 1 was performed except that the contact time was changed to Table 1. The quality of the obtained copolyester resin composition is intrinsic viscosity 0.60 dl / g, haze 1.0%, antimony content 230 ppm, cyclic trimer content 0.45 wt%, fusion rate Was 8%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Example 9]
The diol component to be contacted was diethylene glycol, and the same procedure as in Example 1 was performed except that the contact temperature was 200 ° C. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity 0.51 dl / g, haze 0.6%, antimony content 185 ppm, cyclic trimer content 0.36 wt%, fusion rate Was 2%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.
[Example 10]
It was carried out in the same manner as in Example 1 except that the contact time and temperature were changed to Table 1. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.50 dl / g, haze is 0.5%, antimony content is 150 ppm, cyclic trimer content is 0.30 wt%, fusion rate Was 2%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.
[Example 11]
It was carried out in the same manner as in Example 1 except that the contact time and temperature were changed to Table 1. The quality of the obtained copolyester resin composition is as follows: intrinsic viscosity is 0.70 dl / g, haze is 1.0%, antimony content is 250 ppm, cyclic trimer content is 0.45 wt%, fusion rate Was 10%, which was good. Moreover, the moldability with a film was favorable and the precipitation property of the cyclic trimer of the obtained film was favorable. The results are shown in Table 2.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that the mixing ratio of isophthalic acid contained was changed to Table 1. The quality of the obtained copolyester resin composition was high, with a haze of 1.1% and a cyclic trimer content of 0.48 wt%. The results are shown in Table 1. Moreover, although the moldability with a film was favorable, the precipitation property of the cyclic trimer of the obtained film was unsatisfactory.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the mixing ratio of isophthalic acid contained was changed to Table 1. The results are shown in Table 2. Fusion occurred in the drying process, and a product film could not be obtained.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the diol component to be contacted was triethylene glycol and the contact temperature was 210 ° C. The results are shown in Table 1. Molding with a film has a low intrinsic viscosity and tears, and a product film cannot be obtained.

[Comparative Example 4]
It implemented by the method similar to Example 1 except having made temperature and time to contact into Table 1. The results are shown in Table 2. Fusion occurred in the drying process, and a product film could not be obtained.

[Comparative Example 5]
It implemented by the method similar to Example 1 except having made temperature and time to contact into Table 1. The results are shown in Table 2. Molding with a film has a low intrinsic viscosity and tears, and a product film cannot be obtained.

[Comparative Example 6]
It implemented by the method similar to Example 1 except having made temperature and time to contact into Table 1. The results are shown in Table 2. Fusion occurred in the drying process, and a product film could not be obtained.

[Comparative Example 7]
The same procedure as in Example 1 was performed except that the solution to be contacted was other than the diol component and the contact temperature and time were set as in Table 1. The results are shown in Table 2. Fusion occurred in the drying process, and a product film could not be obtained.

[Comparative Example 8]
The same procedure as in Example 1 was performed except that the solution to be contacted was other than the diol component and the contact temperature and time were set as in Table 1. The results are shown in Table 2. Fusion occurred in the drying process, and a product film could not be obtained.

Claims (6)

  A polyester resin composition comprising terephthalic acid or a dicarboxylic acid component mainly composed of terephthalic acid and ethylene glycol or a diol component mainly composed of this, wherein the dicarboxylic acid component is 20 to 40 mol% isophthalic acid and 150 to 150% antimony element. A copolymerized polyester resin composition containing 250 ppm, having a haze of 0.5 to 1.0% and a fusion rate of 10% or less.   The copolyester resin composition according to claim 1, wherein the intrinsic viscosity is 0.50 to 0.70 dl / g.   The copolymerized polyester resin composition according to claim 1 or 2, wherein the content of the cyclic trimer is 0.35 to 0.45 wt%.   The copolyester according to any one of claims 1 to 3, wherein a polyester resin composition obtained by copolymerizing 20 to 40 mol% of isophthalic acid is brought into contact with a diol component at a temperature of 100 ° C to 200 ° C for 30 minutes to 200 minutes. A method for producing a polymerized polyester resin composition.   The method for producing a copolyester resin composition according to claim 4, wherein the diol component is at least one of ethylene glycol, triethylene glycol, and diethylene glycol.   The copolyester film for optics obtained from any one of Claims 1-5.