JP2000026584A - Polyester and film made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polyester having excellent adhesiveness to a rotary chill roll in the production of a film, causing little staining of electrostatic wire, etc., and having high productivity and hygiene by including a specific sulfonic acid salt at a specific ratio based on acid component and specifying the amount of diethylene glycol. SOLUTION: The objective polymer contains 0.1-45 m-mol.% (based on the acid component of the polyester) of a sulfonic acid quaternary phosphonium salt having ester-forming functional group (preferably 3,5- dicarboxybenzenesulfonic acid tetrabutylphosphonium salt, etc.), and the amount of diethylene glycol in the polymer is adjusted to 0.3-5 wt.%. The objective polymer is preferably a polyethylene terephthalate or a polyethylene-2,6- naphthalate. When the objective polymer is immersed in 50% ethanol at 250 deg.F for 2 hr, the amount of detectable sulfonic acid quaternary phosphonium salt is preferably <=1 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester and a film comprising the same, and more particularly, to a sulfonic acid quaternary phosphonium salt having an ester-forming functional group in an amount of 0.1 to 45 mmol% based on the acid component of the polyester. And a film comprising the polyester, wherein the amount of the diethylene glycol component in the polymer is 0.3 to 5.0% by weight.

[0002]

2. Description of the Related Art Polyester films typified by polyethylene terephthalate films have excellent physical and chemical properties and are therefore used in a wide variety of applications such as magnetic tapes, electrical insulation, capacitors, photographs, and packaging.

[0003] A polyester film is usually produced by quenching a film-like polyester melt melt-extruded from an extrusion die on the surface of a rotary cooling drum, and then stretching it vertically and horizontally. In this case, in order to eliminate the surface defects of the film and increase the uniformity of the thickness, it is necessary to uniformly adhere the melt-extruded film-like polyester to the surface of the rotary cooling drum. A method in which a metal electrode in the form of a wire (hereinafter, referred to as an electrostatic wire) is provided in the vicinity of a side surface (a surface not in contact with the drum) to deposit an electrostatic charge on the surface of the film-like melt (hereinafter, referred to as an electrostatic casting method) It has been known.

[0004] It is important to improve productivity and reduce production cost in film production, as well as to improve film quality. For this purpose, the peripheral speed of the rotary cooling drum is increased to increase the film production speed. Is the most effective way. Therefore, when the peripheral speed of the rotating cooling drum is increased in the electrostatic casting method, the amount of electrostatic charge per unit area on the surface of the film-like material is reduced, the adhesion to the rotating cooling drum is reduced, and the film surface has defects. Or cause
Problems such as uneven film thickness occur.

In order to enhance the adhesion, the voltage applied to the electrode can be increased to increase the amount of electrostatic charge deposited on the molten polyester. However, if the applied voltage is too high, the space between the electrode and the rotary cooling drum can be increased. Arcing may occur, destroying the film on the surface of the cooling drum and damaging the surface of the cooling drum. Therefore, it is substantially impossible to increase the voltage applied to the electrodes to a certain degree or more.

As a method of overcoming the limitations of the electrostatic casting method and increasing the film forming speed to produce a polyester film with high efficiency, various methods for lowering the specific resistance of the molten polyester have been proposed.

For example, in Japanese Patent Publication No. 7-5765,
5. A sulfonic acid quaternary phosphonium salt having an ester-forming functional group in an amount of 0.1 to 45 mmol% based on the bifunctional carboxylic acid component is contained in the polymer chain, and the value of the AC volume resistivity of the molten film is 6. It has been proposed to use aromatic polyesters of 5 × 10 ⁸ Ωcm or less.

However, when such a film forming method is carried out, a sublimate, which is considered to have been generated from the film-like molten polyester extruded from the extrusion die, adheres to the electrostatic wire as dirt, resulting in a decrease in current or discharge spark. In addition to the need to replace the electrostatic wire in a short period of time, the sublimate also adheres to the surface of the extrusion die and streak-like unevenness is formed on the film surface. It has been found that there is a problem that productivity is extremely low, such as frequent cleaning of gold. When the polyester is used for a film for packaging or the like, from the viewpoint of hygiene, it is necessary that the quaternary phosphonium salt of sulfonic acid contained in the polyester does not elute from the polyester film in a large amount. No mention is made of this.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present inventors
When producing polyester film, to obtain polyester with excellent adhesiveness on rotating cooling drum, excellent in productivity by suppressing electrostatic wire contamination and sublimate adhesion to extrusion die, and excellent in hygiene As a result of intensive studies, the present invention has been achieved.

[0010]

That is, the present invention provides a method for producing a polyester, comprising:
A polyester comprising a sulfonic acid quaternary phosphonium salt having an ester-forming functional group, and having a diethylene glycol component content of 0.3 to 5.0 wt% in the polymer.

The polyester of the present invention has an acid component (bifunctional carboxylic acid component) of from 0.1 to 45%.
It is necessary for mmol% to be occupied by the quaternary phosphonium sulphonic acid salt having an ester-forming functional group. When the amount of the quaternary phosphonium sulfonic acid salt is less than 0.1 mmol%, the film formation rate cannot be improved, and
If the amount exceeds mmol%, the number of surface defects of the film increases, which is not preferable.

Preferred examples of the quaternary phosphonium salt having an ester-forming functional group include compounds represented by the following formula.

[0013]

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Here, A is a group containing an aromatic ring having 6 to 18 carbon atoms, and Y ¹ and Y ² are the same or different and are a hydrogen atom or an ester-forming functional group (provided that Y ¹ and Y ² Are not hydrogen atoms at the same time), and n is 1 or 2, R ¹ , R ² , R ³ and R ⁴ are the same or different and have an alkyl group having 1 to 18 carbon atoms, a benzyl group or a carbon atom having 1 to 18 carbon atoms. 6 to 12 aryl groups.

In the above formula, A is a group containing an aromatic ring having 6 to 18 carbon atoms, and a preferable example is a group containing a benzene skeleton, a naphthalene skeleton or a biphenyl skeleton. Such an aromatic ring may be substituted with, for example, an alkyl group having 1 to 12 carbon atoms in addition to Y ¹ , Y ² and a quaternary phosphonium sulfonic acid base. Y
¹ and Y ² represent a hydrogen atom or an ester-forming functional group, for example, -COOH, -COOR ', -OCO
_{R ', - (CH 2)} n OH, - (OCH 2) n OH , and the like. In these groups, R 'is a lower alkyl group having 1 to 4 carbon atoms or a phenyl group, and n is an integer of 1 to 10. Preferred examples of R ′ include methyl, ethyl, n-propyl, iso-propyl, n-butyl and the like. Further, groups R ¹ , R ² , R ³ and R ³ constituting a part of the quaternary phosphonium base of sulfonic acid
⁴ is the same or different, and examples of the alkyl group having 1 to 18 carbon atoms include methyl, ethyl, propyl, butyl, dodecyl, stearyl and the like. Carbon number 6-1
Examples of the aryl group 2 include phenyl, naphthyl,
Biphenyl and the like can be mentioned.

Preferred specific examples of the quaternary phosphonium salt of sulfonic acid include tetrabutylphosphonium salt of 3,5-dicarboxybenzenesulfonic acid, ethyltributylphosphonium salt of 3,5-dicarboxybenzenesulfonic acid,
5-dicarboxybenzenesulfonic acid benzyltributylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid phenyltributylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid tetraphenylphosphonium salt, 3,
Butyltriphenylphosphonium 5-dicarboxybenzenesulfonate, tetrabutylphosphonium 3,5-dicarbomethoxybenzenesulfonate, ethyltributylphosphonium 3,5-dicarbomethoxybenzenesulfonate, 3,5-dicarbomethoxy Benzyl sulfonic acid benzyl tributyl phosphonium salt, 3,5-dicarbomethoxy benzene sulfonic acid phenyl tributyl phosphonium salt, 3,
Tetrabutylphosphonium 5-di (β-hydroxyethoxycarbonyl) benzenesulfonate, tetraphenylphosphonium 3,5-di (β-hydroxyethoxycarbonyl) benzenesulfonate, tetrabutylphosphonium 3-carboxybenzenesulfonate, 3 -Carboxybenzenesulfonic acid tetraphenylphosphonium salt, 3-di (β-hydroxyethoxycarbonyl) benzenesulfonic acid tetrabutylphosphonium salt, 3- (β-hydroxyethoxycarbonyl) benzenesulfonic acid tetraphenylphosphonium salt, 4- (β- (Hydroxyethoxycarbonyl) benzenesulfonic acid tetrabutylphosphonium salt, bisphenol A-3,3-di (sulfonic acid tetrabutylphosphonium salt), 2,6-dicarboxynaphthalene-4-
Tetrabutyl phosphonium sulfonate and the like can be mentioned. The above quaternary phosphonium sulfonic acid salts may be used alone or in combination of two or more.

The bifunctional carboxylic acid component constituting the polyester in the present invention includes, for example, terephthalic acid,
Preferred are naphthalenedicarboxylic acid, isophthalic acid, diphenyldicarboxylic acid and the like. Such carboxylic acids may be used alone or in combination of two or more. On the other hand, as the glycol component, ethylene glycol, tetramethylene glycol and the like can be preferably mentioned, and ethylene glycol is particularly preferable.

The polyester in the present invention needs to contain 0.3 to 5% by weight of a diethylene glycol component in the polymer. When the content of the diethylene glycol component is less than 0.3% by weight, the contamination of the electrostatic wire and the adhesion of the sublimate to the extrusion die are not sufficiently suppressed. When the content of diethylene glycol exceeds 5% by weight, the heat resistance of the produced film becomes insufficient. The amount of diethylene glycol contained in the polymer may be adjusted by adjusting the synthesis conditions of the polyester, or by adding additives, or by adding diethylene glycol as a part of the raw material during the synthesis of the polymer. Alternatively, these may be adjusted in combination. For example, it is known that the addition of a hindered phenolic antioxidant or a phosphate ester is effective for reducing the amount of diethylene glycol.

Such polyesters are substantially linear and have film-forming properties, especially film-forming properties in the molten state. Among these polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalate are particularly preferred. The amount of the polyester is in the range of a substantially linear range and, for example, in an amount of 2 mol% or less based on the total acid components, as long as the effects of the present invention are not impaired.
It is possible to copolymerize a polycarboxylic acid or polyhydroxy compound having a functionality higher than or equal to the functional group, such as trimellitic acid and pentaerythritol.

Further, additives such as pigments, dyes, antioxidants, light stabilizers and light-shielding agents may be added to the polyester of the present invention, if necessary, as long as the surface flatness and dry heat deterioration are not impaired. Can be contained.

In the present invention, the quaternary phosphonium salt of sulfonic acid is 0.1 to 45 mm of the total bifunctional carboxylic acid component.
ol%, and the AC volume resistivity at the time of melting of the polyester resin composition is 2.0 × 10 ⁸ Ωcm or less, and a sufficient amount of electric charge can be imparted to the cooling drum rotating relatively fast, An object of the present invention is to achieve an improvement in film forming speed.

The polyester in the present invention can be produced according to a known method. For example, if polyethylene terephthalate is described as an example for convenience,
Usually, a direct esterification reaction of terephthalic acid and ethylene glycol, a transesterification reaction of a lower alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol, or an addition reaction of terephthalic acid and ethylene oxide is performed. A first step of forming a glycol ester of terephthalic acid and / or a low polymer thereof, and a second step of subjecting the reaction product of the first step to polycondensation by heating under reduced pressure to a desired degree of polymerization. Produced by reaction. At that time, additives such as a catalyst can be optionally used. In order to include the sulfonic acid quaternary phosphonium salt in the polyester, it may be added to the reaction system at any stage until the synthesis of the polyester is completed, or the synthesis of the polyester is completed. This and the quaternary phosphonium salt of sulfonic acid may be fed and contained in, for example, a vented twin-screw kneading extruder.

The polyester of the present invention preferably has a quaternary phosphonium sulfonic acid salt of 1 ppm or less, which is detected after immersion in a 50% ethanol solution at 250 ° F. for 2 hours. When the quaternary phosphonium salt of sulfonic acid detected exceeds 1 ppm, it is not preferable when the film is used for food packaging. In order to make the detection amount of the quaternary phosphonium sulfonic acid salt 1 ppm or less, in the production of the polyester, the sulfonic acid quaternary phosphonium salt is added in the polyester synthesis stage or after the addition to the polyester, and the system is kept at least 3 minutes or more. The quaternary phosphonium sulfonic acid salt may be added at a time when the temperature is 240 ° C. or higher.

The film of the present invention comprises the above-mentioned polyester, but has a thickness of 1 to 300 μm,
It is preferably 200 μm.

The method for producing the polyester film is not particularly limited, but is preferably produced by an electrostatic casting method. For example, melting point (Tm) ° C. to (Tm +
70) Extruded on a rotating cooling drum at a temperature of ° C., rapidly cooled by electrostatic adhesion to form an unstretched film of, for example, 20 to 500 μm, and then unstretched film in a uniaxial direction (longitudinal or transverse direction) (Tg− 10) 2.5 ° C at a temperature of (° C) to (Tg + 70) ° C (Tg; glass transition temperature of polyester).
Stretched at a magnification of up to 6.0 times, and subsequently at a temperature of (Tg) ° C. to (Tg + 70) ° C. in a direction perpendicular to the stretching direction at a temperature of 2.5 to
It is preferable to obtain a biaxially stretched film by stretching at a magnification of 6.0 times. The stretching method may be either sequential biaxial stretching or simultaneous biaxial stretching. Further, the obtained film is (Tg
(+70) ° C to (Tm) ° C. The heat fixing time is, for example, 1 to 30 seconds.

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. The measurement of each characteristic value in the embodiment is performed by the following method.

(1) Determination of diethylene glycol The polyester was dissolved in a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 1/1, and 1H-N
Measured by MR.

(2) AC Volume Resistivity of Molten Polymer A container having a pair of electrodes inserted in a polymer to be measured was immersed in a heating medium, and the polymer was heated and melted at a temperature of 285 ° C. and kept at this temperature. A voltage of 100 V-50 Hz is applied from an AC power supply externally connected to the electrode inserted into the polymer. At this time, the AC volume resistivity is obtained by calculation from the indicated values of the ammeter and voltmeter, the electrode area, and the distance between the electrodes.

(3) Electrostatic castability In the vicinity of a die for melt-extruding a polymer into a film,
Also, when casting by applying a voltage of 6 kV between the cooling drum and the electrode provided on the top of the extruded film, no surface defects occur and the film can be formed stably without lowering the uniformity of the thickness. Obtain the cooling drum speed. The cooling drum is rated and rated according to the maximum speed as follows. Rank A: A film can be stably formed at a cooling drum speed of 70 m / min or more. Rank B: Cooling drum speed is 60 m / min or more, 70 m
/ Minute can be formed stably. Rank C: Cooling drum speed is 55 m / min or more, 60 m
/ Minute can be formed stably. Rank D: A film can be stably formed only when the speed of the cooling drum is less than 55 m / min.

(4) Dirtiness of Electrostatic Wire In the electrostatic castability test described in (3) above, the test time is extended, and the rate of decrease in the current value of the electrostatic wire due to dirt on the electrostatic wire is examined. The current value at the start of the test and the current value at the end of the test are read, and the difference is divided by the test time to determine the current decrease rate per unit time. The values are ranked and evaluated according to the values as follows. Rank A: Current drop rate of less than 1% / hr Rank B: Current drop rate of 1% / hr to less than 5% / hr Rank C: Current drop rate of 5% / hr to less than 10% / hr Rank D: Current drop rate of 10 % / Hr or more If rank A, there is no practical problem. In ranks B and C, the frequency of replacement of the electrostatic wires increases, which is slightly disadvantageous in terms of production efficiency. At rank D, it cannot be put to practical use.

(5) Sublimate adhesion to the extrusion die When the sublimate adheres to the extrusion die, the molten polymer extruded from the die comes into contact with the adhered substance, causing streaks on the film surface. In this method, the presence or absence of the streaks is determined by visual observation. The molten polymer is extruded from an extrusion die at 285 ° C., and after 8 hours, the molten polymer is brought into close contact with a rotary cooling drum and cooled to form a substantially amorphous state. And the film is visually observed. If streaks are observed after the elapse of 8 hours, it is necessary to remove the sublimate attached to the extrusion die, resulting in poor productivity.

(6) Defects on Film Surface This is an evaluation of particulate foreign matter by-produced in the extrusion step from the polymerization of the thermoplastic polyester. The molten polymer is extruded at 285 ° C., closely adhered to a rotary cooling drum, and cooled. A film in an amorphous state was obtained, and then stretched 3.6 times in the machine direction and 3.9 times in the transverse direction to obtain a film having a thickness of 15 mm.
Produce a μm film. This film was observed using a phase-contrast microscope, and the image analyzer Luzex 500 was used.
The maximum length in a microscopic image is 10
Count the number of particles of μm or more. Those having a particle number of 10 / cm ² or less can be put to practical use.

(7) Heat Stability of Film A biaxially stretched film having a longitudinal stretching ratio of 3.5 times, a transverse stretching ratio of 3.5 times and a film thickness of 25 μm is heat-treated at 160 ° C.
Film rupture strength is 50
% Is determined by the heat treatment time required to reduce the temperature to%.
Film rupture strength is 50
%, The heat treatment time required to decrease to less than 700 hours is not suitable for applications where the film usage environment becomes high, such as capacitor applications.

(8) Eluted amount of quaternary phosphonium salt of sulfonic acid by treatment with ethanol solution A film was sampled such that the surface area of one side of the film was 25 inch ² , immersed in a 50% ethanol solution, and placed in an autoclave at 250 ° C. The extract was evaporated to dryness on a hot plate, methanol was added to the residue, and the mixture was subjected to high-performance liquid chromatography (Shimadzu LC-
10AD) to determine the amount of quaternary phosphonium sulfonic acid salt eluted.

Example 1 Dimethyl terephthalate 100
Manganese acetate tetrahydrate (0.038 parts by weight) was added to a mixture of 70 parts by weight of ethylene glycol and 70 parts by weight of ethylene glycol.
The transesterification reaction was carried out while gradually raising the temperature from 240 ° C to 240 ° C. On the way, when the reaction temperature reached 170 ° C., 0.04 part by weight of antimony trioxide was added, and 0.2 part by weight of spherical silica having an average particle diameter of 0.6 μm was further added. A mixture of 0.017 parts by weight of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate and 0.124 parts by weight of ethylene glycol was added as a solution heated to 40 ° C. Subsequently, a transesterification reaction was performed, and after the transesterification reaction was completed, trimethyl phosphate was added to ethylene glycol at 135 ° C. for 5 hours.
A solution (0.049 parts by weight in terms of trimethyl phosphate) that had been heat-treated under a pressure of 1.1 to 1.6 kg / cm2 was added. Thereafter, the reaction product was transferred to a polymerization vessel,
And a polycondensation reaction was carried out under a high vacuum of 0.2 mmHg or less to obtain a polyester having an intrinsic viscosity of 0.60 and a diethylene glycol component amount of 1.5%. The value of the AC volume resistivity at 285 ° C. of this polyester is 5.
It was 5 × 10 ⁷ Ω · cm.

After drying the polyester pellets at 170 ° C. for 3 hours, the polyester pellets were supplied to an extruder hopper and melted at a melting temperature of 2 ° C.
It was melt-extruded to 200 μm through a 1 mm slit die at 90 ° C., and was tightly solidified on a rotary cooling drum having a surface temperature of 20 ° C. using a linear electrode. At this time, the maximum casting speed at which the cooling film could be stably produced without gradually increasing the speed of the cooling drum and causing surface defects due to poor adhesion was 105 m / min. Next, this unstretched film is preheated at 75 ° C., heated by a single IR heater having a surface temperature of 900 ° C. from 15 mm above between low-speed and high-speed rolls and stretched 3.6 times in the machine direction. This uniaxially stretched film was supplied to a stenter and stretched 3.9 times in the transverse direction at 105 ° C.
After heat-setting for 2 seconds, a biaxially stretched film having a thickness of 14 μm was obtained. Table 1 shows the properties of this film.

Comparative Example 1 The procedure of Example 1 was repeated except that tetrabutylphosphonium 3,5 dicarboxybenzenesulfonate was not added. Table 1 shows the results.

Examples 2 and 3 and Comparative Example 2 The procedure of Example 1 was repeated except that the amount of 3,5 dicarboxybenzenesulfonic acid tetrabutylphosphonium salt was changed as shown in Table 1. Table 1 shows the results.

Example 4 and Comparative Example 3 After transesterification, tetrakis [methylene-3 (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate methane] was 0.08 parts by weight, The procedure was performed in the same manner as in Example 1 except that 0.12 part by weight of the reaction product was added and the reaction product was transferred to a polymerization vessel. Table 1 shows the results.

Example 5 and Comparative Example 4 The procedure of Example 1 was repeated except that 6.6 parts by weight and 8 parts by weight of diethylene glycol were added to a mixture of 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol. went. Table 1 shows the results.

Example 6 The procedure of Example 6 was repeated except that tetraphenylphosphonium 3,5-dicarboxybenzenesulfonate was used in the amount shown in Table 1 in place of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate. Performed similarly to 1. Table 1 shows the results.

Example 7 The synthesis reaction of a polyester resin was completed without adding 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt, and the resulting mixture was formed into chips. The extruder is fed at a rate of 20 kg / hr, and 3,5-dicarboxybenzenesulfonate tetrabutylphosphonium salt is fed thereto at a rate of 10 mmol% (in this case, the degree of vacuum of the vent hole is reduced). The procedure was the same as in Example 1 except that the temperature was set to 1 mmHg and the cylinder temperature was set to 285 ° C. to perform melt kneading. Table 1 shows the results.

Example 8 100 parts by weight of bis-β-hydroxyethyl ester of terephthalic acid and terephthalic acid 6
A mixture of 29 parts by weight of ethylene glycol and 0.031 part by weight of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate in 5 parts by weight was subjected to an esterification reaction at a temperature of 210 to 230 ° C. The reaction was terminated when the amount of distilled water generated by the reaction reached 13 parts by weight, and 0.027 parts by weight of antimony trioxide and trimethyl phosphate were heated at 135 ° C. for 5 hours per 100 parts by weight of the reaction product. A treated solution (0.002 parts by weight in terms of trimethyl phosphate) was added. Thereafter, the reaction product was transferred to a polymerization vessel, heated to 290 ° C., and subjected to a polycondensation reaction under a high vacuum of 0.2 mmHg or less to obtain a polyester. The characteristics were evaluated in the same manner as in Example 1 using this polyester.
Table 1 shows the results.

Example 9 Dimethyl terephthalate (DM
T) 100 parts by weight / hr and ethylene glycol 70
Parts by weight / hr: manganese acetate 0.05 mol% / DM
T and a catalyst of 0.01 mol% of zinc acetate / DMT were continuously supplied to a continuous transesterification reaction tank, and heated to 150 to 250 ° C. while distilling off methanol to carry out a transesterification reaction. Next, the transesterification reaction product obtained was added with 0.1 mol% of phosphorous acid / DMT, 0.01 mol% of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate / DMT, and 0.1 mol% of antimony trioxide as a polymerization catalyst. After adding 03 mol% / DMT,
Continuously fed to the initial polymerization tank,
The reaction was carried out at a temperature of 1 hour. Further, it was reacted in a molten state at 5 mmHg in an intermediate polymerization tank at 280 ° C. for 2 hours, and then continuously fed into the final polymerization tank in a molten state at 1 mmHg and reacted at 290 ° C. for 10 minutes to obtain a polyester resin. A composition was obtained. The properties were evaluated in the same manner as in Example 1 using this polyester resin composition. Table 1 shows the results.

[0045]

[Table 1]

[0046]

According to the present invention, when producing a polyester film, the adhesiveness on a rotary cooling drum is excellent, the contamination of an electrostatic wire and the adhesion of a sublimate to an extrusion die are suppressed, and the productivity is excellent. In addition, it is possible to provide a polyester resin composition and a polyester film excellent in hygiene.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4F071 AA43 AC05A AC14 AE19A AF05Y AF55 AH04 AH12 AH14 BA01 BB06 BB08 BC01 4J029 AA03 AB04 AC02 AE03 BA03 BA05 BF09 CB05A CB06A CB10A CC05A CH02 CH03 FC02 DB02 KE05

Claims (3)

[Claims] 1. An acid component of the polyester of 0.1 to 0.1.
A polyester comprising 45 mmol% of a sulfonic acid quaternary phosphonium salt having an ester-forming functional group, and wherein the amount of a diethylene glycol component in the polymer is 0.3 to 5.0 wt%. 2. 250 ° F. in a 50% ethanol solution;
2. The quaternary phosphonium sulfonic acid salt detected after immersion for 2 hours is 1 ppm or less.
Polyester as described. 3. A film produced from the polyester according to claim 1 or 2.