JPH01172448A - Polyester composition for film - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in film forming speed without causing the formation of foreign matter, by regulating the volume resistivity of the polymer to be in a specified range by adding a specified amount of a potassium compound in the production of a thermoplastic polyester by transesterification. CONSTITUTION:In the production of a thermoplastic polyester (e.g., polyethylene terephthalate) by transesterification, the volume resistivity of the polymer at 285 deg.C is regulated to 7X10<6>-4X10<7>OMEGA.cm by adding 0.002-0.0072pt.wt. (in terms of potassium element), per 100pts.wt. polyester, potassium compound to the system. Preferable examples of said potassium compounds include potassium hydroxide, potassium acetate and potassium benzoate. In this way, it is possible to produce a polyester film low in surface defects in a high efficiency by improving the adhesion of the sheet produced by melt-extruding the obtained thermoplastic polyester to the surface of a rotary cooling drum.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a polyester composition for films, and more specifically to a polyester composition for films that can produce polyester films with few or no surface defects with high efficiency. Regarding.

<Prior art> Polyesters, represented by polyethylene terephthalate, have excellent physical and chemical properties and are widely used in film fields such as magnetic tape applications, electrical insulation, capacitor applications, photographic applications, and packaging applications. There is.

Polyester films are usually produced by melt-extruding sheet polyester using an extruder, rapidly cooling it on the surface of a cooling body such as a rotating cooling drum, and then biaxially stretching it in the longitudinal and transverse directions. In film production, increasing productivity and reducing manufacturing costs are important issues as well as improving quality, and to achieve this, it is necessary to increase the peripheral speed of the rotating cooling drum and increase the film forming speed. This is an effective method.

However, as the circumferential speed of the rotary cooling drum was increased to improve the film forming speed, the adhesion of the sheet polyester to the surface of the cooling drum decreased, making it impossible to obtain a uniform film. The entrainment of air between the film and the drum causes defects on the film surface.

When rapidly cooling sheet-like polyester, a wire-shaped electrode is installed between the extrusion die and the surface of the rotating cooling drum to deposit an electrostatic charge on the top surface of the unsolidified sheet-like material, and then the sheet-like material is placed on the surface of the cooling body. The electrostatic casting method for obtaining a uniform film by adhesion is well known (Japanese Patent Publication No. 37-6142, etc.)
. However, even in this electrostatic casting method, if the circumferential speed of the rotating cooling drum is increased in order to increase the film forming speed,
The amount of electrostatic charge per unit area on the surface of the sheet-like material closely attached to the cooling drum surface decreases, the adhesion between the sheet-like material and the rotating cooling drum decreases, and defects appear on the film surface. Therefore, in order to increase the adhesion between the sheet material and the rotating cooling drum, the voltage applied to the electrode installed between the extrusion die and the surface of the rotating cooling drum is increased, and the electrostatic charge on the surface of the sheet material is increased. However, if the applied voltage is too high, electric arcs will occur between the electrodes and the surface of the cooling drum, destroying the sheet-like material on the surface of the cooling drum, and causing damage to the surface of the cooling drum. This will cause damage to the top. Therefore, it is virtually impossible to increase the voltage applied to the electrodes above a certain level, and there is a limit to increasing the film forming rate and obtaining a uniform film using the conventional electrostatic casting method.

In order to overcome the limitations of the electrostatic casting method, improve the film forming speed, and produce a highly efficient, uniform polyester film with no surface defects, Japanese Patent Publication No. 10231/1983 discloses the use of alkali metals and alkaline earths. A method has been proposed for controlling the resistivity of a molten polymer by containing similar metals or their compounds to produce polyester films with high efficiency.

The resistivity control agents specifically exemplified in this publication include magnesium oxide, calcium oxide, lithium chloride,
Sodium chloride, calcium chloride.

Strontium chloride, calcium hydride, strontium hydride, sodium sulfate, calcium sulfate, barium sulfate, sodium carbonate, calcium carbonate, calcium phosphate, calcium acetate, lithium acetate, strontium acetate, barium acetate.

These are strontium benzoate, barium benzoate, sodium phthalate, calcium phthalate, calcium terephthalate, and barium prephthalate, and at least one of these is contained in o, oos to 1% by weight to increase the specific resistance of the molten polymer. The resistance is controlled to 2×10 7 to 5×10 8 Ω·C11I to improve the adhesion between the polyester sheet and the rotating cooling drum. However, polymers using the above-mentioned specific compounds also have limitations, and it is not possible to further increase the efficiency of producing polyester films using them.

Further, in Japanese Patent Publication No. 61-40538M, per 100 fifi parts of the polynisdel in thermoplastic polyester,
The inorganic fine powder is 0.01 to 2 parts by weight, and the alkali metal compound soluble in ethylene glycol is 0.01 to 2 parts by weight in terms of metal.
A method for producing a polyester film characterized by containing 0001 to 0.0025 parts by weight has been proposed. In this method, it is essential to add inorganic fine particles, and even if an attempt is made to increase the efficiency of polyester film production without adding these inorganic fine particles, satisfactory results will not be obtained. Furthermore, this method also has its limitations, and it is not possible to obtain satisfactory results when attempting to further increase the efficiency of polyester film production.

In addition, JP-A-59-62626 discloses that when producing polyester by direct polymerization, after the esterification rate reaches a predetermined value, 50 to 400 ppm of a phosphorus compound is added to the produced polyester as calcium atoms. The ratio of phosphorus atoms to calcium atoms is 1.2≦Ca
/P≦3.0. A method for producing polyester has been proposed, which is characterized in that 3.0 to 20 ppm of at least one alkali metal compound selected from sodium and potassium compounds is added as alkali metal atoms.

Similarly, JP-A-59-62627 discloses that when producing polyester by a direct polymerization method, after the esterification rate reaches a predetermined value, a magnesium compound is added as a magnesium atom to the produced polyester, at a concentration of 30 to 400 ppm.
Phosphorus compounds have a ratio of phosphorus atoms to magnesium atoms of 1.2
≦Ha/P≦20. A method for producing polyester has been proposed, which is characterized in that 3.0 to 50 ppm of at least one alkali metal compound selected from sodium and potassium compounds is added as alkali metal atoms.

However, according to the research results of the present inventors, when polyester is produced by the transesterification method, when such large amounts of calcium or magnesium compounds, phosphorus compounds, and alkali metal compounds are added to the polyester produced, by-products are produced. It became clear that the amount of foreign matter increased and the quality of the product film deteriorated.

By the way, as described in JP-A No. 60-34826, the upper limit of the conventional electrostatic (I) strike method was said to be 40 to 50 m/min at the peripheral speed of the cooling drum. In order to reduce the circumferential speed by 1q, please refer to JP-A-62-1527.
As described in Publication No. 15, (1) A method in which the electrode for applying an electrostatic charge is made into a pin-shaped electrode, a cap, a cooling body such as a kit' stain drum, or a double electrode.

■ A method in which an electrostatic charge is applied under a specific gas flow or under pressure.

■ A combination of electrostatic casting and air knife methods, a combination of small-diameter extrusion rolls, or a combination of air suction methods.

■ A method in which the surface of the cooling body to which electrostatic charge is applied is made into a roll with a rough surface similar to sandblasting.

Other methods have been proposed.

Specifically, as described in JP-A No. 61-255, H (It is 1
50ppm, 2n 15ppm, K 15ppm
In some cases, the maximum casting speed can be increased to 72 m/min by including as much as 151 ppm of p, but as mentioned above, when such a large amount of metal is present in polyester by the transesterification method, by-products Foreign matter occurs,
Moreover, the thermal stability of the produced polyester is also reduced.

<Purpose of the Invention> As a result of intensive study on a method for obtaining a polyester film with higher efficiency, the present inventor found that when polyester is formed into a polyester film using the electrostatic cooling method, if the polyester used is modified with a specific compound, melt extrusion becomes possible. The inventors have discovered that it is possible to further improve the adhesion between the sheet material and the surface of the rotating cooling drum, and have arrived at the present invention.

An object of the present invention is to provide a polyester composition that improves the adhesion between a sheet-like material and the surface of a rotating cooling drum, and allows for highly efficient production of a polyester film with few or no surface defects.

<Configuration/Effects of the Invention> According to the present invention, an object of the present invention is to contain polyester 10 in thermoplastic polyester produced by a transesterification method.
Potassium element per 0 weight 4 parts is 0.0020-0.00
Contains a potassium compound in a proportion of 72 parts by weight, and has a polymer volume resistivity of 7X106 to 4 at 285°C.
This is achieved by a polyester composition for film that has a small amount of foreign matter and has high-speed film forming properties, which is characterized by a resistance of X107 Ω·cm.

As the thermoplastic polyester in the present invention, polyethylene terephthalate, polyethylene-2°6-naphthalate, copolyesters having ethylene terephthalate as the main repeating unit, and copolyesters having ethylene-2,6-naphthalate as the main repeating unit are particularly preferred. Copolymerization components of the copolyester include aromatic dicarboxylic acids such as isophthalic acid and adipic acid, aliphatic dicarboxylic acids, and oxycarboxylic acids such as oxybenzoic acid.

trimethylene glycol, tetramethylene glycol,
Examples include aliphatic dihydroxy compounds such as 1,4-cyclohekyrin dimetatool, and polyoxyalkylene glycols such as polyethylene glycol and polybutylene glycol. The thermoplastic polyester may be blended with additives such as a stabilizer 9 and a colorant, and may also be blended with or contain inorganic fine particles to improve slipperiness.

Such thermoplastic polyesters are produced by transesterification. For example, a lower alkyl ester of terephthalic acid and ethylene glycol are transesterified to form a monomer or initial polymer, which is then stirred at a temperature above its melting point under vacuum or under an inert gas flow. While adding, the intrinsic viscosity is 0.45-0.75
The polycondensation reaction is carried out until a certain degree is reached. At that time, additives such as catalysts can be optionally used as necessary.

Examples of potassium compounds in the present invention include potassium hydroxide, potassium acetate, potassium propionate, potassium acetate, potassium benzoate, potassium carbonate, potassium sulfate, and potassium nitrate. One or more of these potassium compounds can be used.

It is desirable that these potassium compounds maintain a good dispersion state during the production of polyester and do not generate coarse particles or generate only a small amount of coarse particles. From this point of view, potassium hydroxide, potassium acetate, and potassium benzoate are particularly preferred.

In the present invention, methods for incorporating potassium compounds such as potassium acetate and potassium hydroxide into polyester include adding the potassium compound as a solid during polyester production, and adding the potassium compound to glycol, especially ethylene glycol. A method of adding in a dispersed state can be used. Alternatively, the potassium compound may be added in a state dissolved in water. The potassium compound may be added at any time during the production of polyester, but it is preferably added when the transesterification reaction is substantially completed and when the polycondensation reaction has progressed and the intrinsic viscosity does not exceed 0.2. It is better to do so. The potassium compound may be added once or in two or more parts.

In addition, a polyester containing a high concentration of a potassium compound is separately manufactured, and this is melt-mixed with a polyester that does not contain a potassium compound or contains a potassium compound at a low concentration during the melt extrusion stage when manufacturing a polyester film.
The potassium content can also be adjusted at predetermined times. This master polymer approach is the preferred method.

The amount of the potassium compound added is such that the potassium element is 0.0020 to 0.0072 parts by weight per 100,000 parts of polyester, and the volume resistivity of the polymer at 285°C is 7 x 10 to 4 x 10 Ω cm. , preferably potassium element is 0.0031 to 0.006
The proportion is 8 parts by weight, and the amount is such that the polymer volume resistivity at 285°C is 8 x 106 to 1.8 x 107 Ω-cm, and particularly preferably the potassium element is 0.00
The ratio is 36 to 0.0062 parts by weight at 285°C
The polymer volume resistivity in is 1×107~1.7×1
070 cm. Unlike the above alkali metal compounds, the potassium compound has excellent dispersibility in the polymer even when added in such an amount, and does not generate coarse particles or generates only a small amount of coarse particles. Furthermore, when a film is produced from a polyester composition containing a potassium compound by an electrostatic adhesion method, there is no arc discharge, and the film can be produced with high efficiency.

In the present invention, the potassium compound-containing thermoplastic polyester composition thus heated is melt-extruded into a sheet, electrostatic charges are deposited on the sheet, the sheet is brought into close contact with the surface of a rotating cooling drum, and the composition is rapidly cooled to form an unstretched sheet. Use polyester film. As the melt extrusion conditions, electrostatic charge deposition means, cooling means, etc., two conventionally accumulated conditions can be employed. For example, as a means for electrostatic charge deposition,
The method described in Publication No. 2, etc. can be adopted.

The thermoplastic polyester used in the present invention is extremely easy to deposit electrostatic charges, and according to the present invention, electrostatic charges can be deposited on a sheet-like material under conditions that are more relaxed than those of conventional conditions. Even if the film speed is increased, electrostatic charges can be sufficiently deposited.

The unstretched film thus obtained can be stretched in at least one direction, and this stretching can be carried out under two conventional conditions and methods. For example, the unstretched film is heated to a temperature (T1) of 1 g to (Tg+70)'C [where DQ is the glass transition temperature of polyester].
Stretched in the - axial direction, then ■1~(T++40)'C
A biaxially oriented polyester can be obtained by stretching the polyester in a direction perpendicular to the stretching direction at a temperature of .

Although the stretching ratio depends on the desired film properties, the area ratio is preferably 4 times or more, more preferably 6 times or more, particularly 8 times or more.

It is preferable that heat fixation is carried out at 170 to 230°C for 1 to 120 seconds.

By using the polynisder composition of the present invention, a film with improved surface defects can be produced stably at a higher speed.

<Example> The present invention will be further explained below with reference to Examples.

In addition, "parts" in the examples mean parts by weight, and measurements and evaluations of polynisdel's intrinsic viscosity, electrostatic castability, polymer volume resistivity, film surface defects, etc. were performed by the following methods.

1. Intrinsic viscosity Measured at 35°C using 0-chlorophenol as a solvent.

2. When casting by applying a voltage of 7,000 V between the casting drum and the electrode installed on the top of the extruded sheet in the nozzle that melts and extrudes the electrostatically castable polymer into a sheet, the maximum value that can be stably formed into a film is The casting drum speed was ranked and evaluated as follows.

Rank-A: A film can be stably formed at a casting drum speed of 60 m for 7 minutes or more.

Rank-B: Casting drum speed 55-60m
Films can be stably formed in minutes.

Rank-C: Film cannot be stably formed at a casting drum speed of 55 m for 7 minutes or more.

3. Polymer volume resistivity Using the apparatus shown in Figure 1, measure the polymer (
1) A container (3) into which a pair of electrodes (2) were inserted was immersed in a heating element (4), and the polymer was melted by heating to a temperature of 285°C and maintained at this temperature. Electrode inserted into the polymer (2
) was applied a predetermined voltage from a DC power supply (5) connected externally. At this time, the volume resistivity was calculated from the indicated values of the ammeter (6) and voltmeter (7), the electrode area, and the distance between the electrodes.

4. Film surface defects After extruding the thermoplastic polyester at 290℃ and cooling it on the surface of a cooling drum using the electrostatic casting method,
．． Stretched 6 times and 3.9 times in the lateral direction, heat 15
A film of μ was produced.

This film was observed using a phase microscope, and the number of particles with a maximum length of 10 μI11 or more in the microscope image was counted using an image analyzer Luzex 500 (manufactured by Nippon Regulator).

Example 1 100 parts of dimethyl terephthalate and 7 parts of ethylene glycol
0.038 part of manganese acetate tetrahydrate was added to 0 part of the mixture, and the transesterification reaction was carried out while gradually raising the temperature from 150°C to 240°C. ) Add 0.025 parts of trimethyl phosphate to the resulting reaction mixture, react for 15 minutes, add 20.045 parts of andemo trioxide, react for an additional 5 minutes, and then add 0.138 parts of potassium acetate to ethylene. It was added in a state dissolved in 1.5 parts of glycol. Subsequently, the temperature was raised to 290° C., and a polycondensation reaction was performed under a high vacuum of 0.2 mmHg or less to obtain polyethylene terephthalate (^) having an intrinsic viscosity of 0.60.

On the other hand, in a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol, 0.038 parts of manganese acetate tetrahydrate was added.
The transesterification reaction was carried out while gradually increasing the temperature from 150'C to 240°C. 01025 parts of trimethyl phosphate was added to the obtained reaction product, reacted for 15 minutes, added 0.045 parts of antimony trioxide, reacted for another 10 minutes, and then added 1.0 part of calcium carbonate with an average particle size of 160 μm. was added mixed with 5 parts of ethylene glycol. Subsequently, the temperature was raised to 290'C, and the thickness of 0.2 mm
A polycondensation reaction was carried out under a high vacuum of 1 liter (1 liter or less) to obtain polyethylene terephthalate (8) with an intrinsic viscosity of 0.60.

In addition, 0.038 parts of manganese acetate tetrahydrate was added to a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol.
The transesterification reaction was carried out while gradually raising the temperature from 150°C to 250″C. 0.025 parts of trimethyl phosphate was added to the obtained reaction product, and the reaction was continued for 15 minutes. 0.045 part of antimony oxide was added.Then, the temperature was raised to 290°C, and 0.2 mmf1gmmHg
The following polycondensation reaction was performed to obtain 1q of polyethylene terephthalate (C) having an intrinsic viscosity of 0.60.

The thus obtained polyethylene terephthalate (A),
(B) and (C) are mixed so that the potassium element content in polyethylene terephthalate (D) after mixing is polymer ioo
The content of calcium carbonate having an average particle size of 1.0 μm was 0.0037 parts by weight per ω part of the polymer and 0.1 parts by weight per 100 i parts of the polymer. This polymer (D
) volume resistivity at 285℃ is 2.0×107 Ω
・It was cm.

When a polyester film was T4a-treated using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below.

Comparative Example 1 Polyethylene terephthalate (A) was produced in the same manner as in Example 1, except that 0.138 parts of potassium acetate was changed to 0.191 parts of sodium acetate trihydrate, and the intrinsic viscosity was 0. .60 polyethylene terephthalate (E) was obtained.

The content of sodium element in the polyethylene terephthalate (F) after mixing the polyethylene terephthalate (8) and polyethylene terephthalate (c) obtained in Example 1 with the above polyethylene terephthalate (E) is 0.0030 per 100 parts by weight of the polymer. Part by weight, average particle size 1.0
The mixture was mixed so that the content of μm calcium carbonate was 0.1 parts by weight per 100 parts by weight of the polymer. The volume resistivity of this polymer ([) at 285°C is 9.0X107
It was Ω-cm.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

Comparative Example 2 When producing polyethylene terephthalate (A) in Example 1, 0.138 parts of potassium acetate was changed to 0.248 parts of calcium acetate monohydrate.
Polyethylene terephthalate (G) having an intrinsic viscosity of 190.60 was obtained in exactly the same manner as in Example 1 except that monohydrate was added in the form of an ethylene glycol slurry.

In Example 1, polyethylene terephthalate (B), polyethylene terephthalate (C), and the above polyethylene terephthalate (G) were mixed into polyethylene terephthalate (with a calcium element content of 0.0% per 100 parts of polymer). 0038 parts by weight, average particle size 1.
The mixture was mixed so that the calcium carbonate content of 0 μm was 0.1 part by weight per 100 parts by weight of the polymer. This polymer (old volume resistivity at 285°C is 3.5X107
It was Ωcm.

When a poly-1 stellate film was produced using this polymer, the electrostatic charge resistance and surface defects of the film are as shown in Table 1 below.

Example 2 100 parts of dimethyl terephthalate and nibrene gelicol 7
0.038 parts of manganese acetate tetrahydrate and 0.018 parts of potassium acetate were added to 0 parts of the mixture, and the mixture was heated from 150°C to 240°C.
The transesterification reaction was carried out while gradually raising the temperature to °C.

Add 0.025 part of trimethyl phosphate to the obtained reaction product, react for 15 minutes, and then add 0.0 part of andepine trioxide.
After adding 45 parts and reacting for an additional 5 minutes, the average particle size was 0.
．． 0.08 part of 8 μm Kaoriite was added. Then up to 290℃! Polycondensation reaction was carried out under high vacuum to obtain polyethylene terephthalate having an intrinsic viscosity of 0.60. 285 of this polymer
The volume resistivity at ℃ was 8.0×10 6 Ω·cm.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

Comparative Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in exactly the same manner as in Example 2, except that 0.018 part of potassium acetate was changed to 0.0213 part of sodium acetate trihydrate. The volume resistivity of this polymer at 285° C. was 8.0×10 7 Ω·cm.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

Example 3 100 parts of dimethyl terephthalate and 7 parts of ethylene glycol
0.038 part of manganese acetate tetrahydrate was added to 0 part of the mixture, and the transesterification reaction was carried out while gradually raising the temperature from 150°C to 240°C. 0.025 part of trimedel phosphate was added to the reactant, and after reacting for 15 minutes, 0.045 part of antimony trioxide was added, and after further reacting for 5 minutes, 0.008 part by weight of potassium hydroxide was added. It was added in a state dissolved in 1.0 part of ethylene glycol.

Furthermore, a slurry of 0.05 part of titanium oxide with an average particle size of 0.3 μm in 0.5 part of ethylene glycol was added, followed by heating to 290°C and under high vacuum at a pressure of 0.2 mmt1g or less. By performing polycondensation reaction, the intrinsic viscosity is 0.60.
Polyni[ethylene terephthalate] was obtained. The volume resistivity of this polymer at 285°C is 1. IX107Ω・
It was cm.

When a polyethylene terephthalate film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below.

Comparative Example 4 Polyethylene terephthalate with an intrinsic viscosity of 0.60 was obtained in the same manner as in Example 3 except that the parts by weight of potassium hydroxide o and ooa in Example 3 were changed to 0.055 parts by weight of sodium acetate trihydrate. Ta. 285℃ of this polymer
The volume resistivity was 7.0×10 7 ΩΦcm.

When a polyethylene terephthalate film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below. This film was colored yellow and had insufficient thermal stability.

Comparative Example 5 In Example 3, 0.008 parts by weight of potassium hydroxide was added to 0.
．． Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in exactly the same manner as in Example 3 except that the amount was changed to 0.029 parts by weight. The volume resistivity of this polymer at 285°C is 7
．． It was 0×106 Ω·cm.

When a polyethylene terephthalate film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below. This film was colored yellow and had insufficient thermal stability.

Comparative Example 6 Except that 0.008 parts by weight of potassium hydroxide in Example 3 was changed to 0.028 parts by weight of magnesium acetate/tetrahydrate, and 0.05 parts of titanium oxide with an average particle size of 0.3 μm was not added. was made exactly the same as in Example 3, and the intrinsic viscosity was 0.62.
of polyethylene terephthalate was obtained.

The volume resistivity of this polymer at 285°C is 2.5×
It was 107 Ω·cm.

When a polyethylene terephthalate film was produced using this polymer, the electrostatic crest properties and surface defects of the film are as shown in Table 1 below.

Comparative Example 7 Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in exactly the same manner as in Example 3, except that potassium hydroxide was changed to 0.008 parts by weight and barium acetate was changed to 0.0056 parts by weight. The volume resistivity of this polymer at 285° C. was 3.0×10 8 Ω·cm.

When producing a polyester film using this polymer, the electrostatic crystal properties and surface defects of the film will be determined in the following section 1.
As shown in the table.

Comparative Example 8 In Example 3, 0.008 parts by weight of potassium hydroxide was changed to 0.020 parts by weight of barium acetate, and the average particle size was 0.3.
Polyethylene terephthalate having an intrinsic viscosity of 0.61 was obtained in exactly the same manner as in Example 3, except that 0.05 part of titanium oxide of μm was not added. The volume resistivity of this polymer at 285° C. was 7.0×10 7 Ω·cm.

When a polyester film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below.

Comparative Example 9 Polyethylene terephthalate having an intrinsic viscosity of 0.61 was obtained in the same manner as in Example 3, except that the lithium oxide containing potassium hydroxide o, ooa was changed to 0.033 parts by weight. The volume resistivity of this polymer at 285° C. was 1.2×10 8 Ω·cm.

When producing a polyester film using this polymer, the electrostatic crystal properties and surface defects of the film will be determined in the following section 1.
As shown in the table.

Example 4 100 parts of dimethyl 2.6-naphthalene dicarboxylate and ■
0.018 part of manganese acetate tetrahydrate was added to a mixture of 50 parts of dylene glycol, and transesterification reaction was carried out while gradually raising the temperature from 150°C to 240°C. After completion of the transesterification reaction, 0.013 part of trimethyl phosphate was added, and 5 minutes later, 0.0097 part of potassium acetate was added. After another 5 minutes, o, ooa parts by weight of titanium acetate were added, and the reaction product was heated to 290'C, and 0.2111 m
The polycondensation reaction is carried out under high vacuum below HO and the intrinsic viscosity is 0.
50 polyethylene-2,6-naphthalate was obtained. The volume resistivity of this polymer at 285°C is 1.3X1
It was 07Ω·cm.

When a polyester film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below.

Comparative Example 10 Polyethylene with an intrinsic viscosity of 0.50 was prepared in the same manner as in Example 4 except that 0.0097 part of potassium acetate was changed to 0.018 part of sodium acetate trihydrate.
2,6-naphthalate was obtained. 285℃ of this polymer
The volume resistivity was 1.0×10 8 Ω·cm.

When a polyester film was produced using this polymer, the electrostatic castability and surface defects of the film are as shown in Table 1 below.

Comparative Example 11 In Example 4, 0.0097 part of potassium acetate was added to 0.0
Polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.50 was obtained in exactly the same manner as in Example 4 except that the amount was changed to 0.008 parts. The volume resistivity of this polymer at 285°C is 1. The resistance was 109Ω・cm.

The electrostatic properties and surface defects of the film when producing a polyester film using this polymer will be discussed in Section 1 below.
Comparative Example 12 As shown in the table, 0.0097 part of 1M potassium was added to 0,1
Polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.45 was obtained in exactly the same manner as in Example 4 except that the amount was changed to 22 parts. The volume resistivity of this polymer at 285°C is 1. It was OX107Ω·cm.

The electrostatic castability and surface defects of the film produced using this polymer are as shown in Table 1 below.

Example 5 Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in the same manner as in Example 3, except that 0.008 parts by weight of potassium hydroxide in Example 3 was changed to 0.025 parts by weight of potassium benzoate. This polymer was heated to 285°C.
The volume resistivity was 1.0×10 7 Ω·cm.

When producing a polyester film using this polymer, the electrostatic properties and surface defects of the film will be determined in the following section 1.
As shown in the table.

Example 6 Polyethylene with an intrinsic viscosity of 0.61 was prepared in the same manner as in Example 2, except that 0.018 parts of potassium acetate was changed to 0.002 parts by weight of potassium carbonate and 0.0043 parts by weight of potassium acetate. Obtained terephthalate. The volume resistivity of this polymer at 285°C is 2.0X1
07 Ω-cm.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

Comparative Example 13 Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in exactly the same manner as in Example 5, except that 0.025 parts by weight of potassium benzoate A in Example 5 was changed to 0.0042 parts by weight. The volume resistivity of this polymer at 285°C was 3.0×10 8 Ω·cm.

The electrostatic castability and surface defects of the film when a polyester film is mounted using this polymer are as described in 1 below.
As shown in the table.

Comparative Example 14 Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained in the same manner as in Example 5 except that 0.025 parts by weight of potassium benzoate was changed to 0.225 parts by weight. The volume resistivity of this polymer at 285°C was e,oxio[iΩ·cm.

The electrostatic castability and surface defects of the film when poly-1 stellate film was produced using this polymer are as described in 1 below.
As shown in the table.

Comparative Example 15 100 parts of dimethyl terephthalate and 7 parts of ethylene glycol
0.038 part of manganese acetate tetrahydrate was added to 0 part of the mixture, and transesterification reaction was carried out while gradually heating the mixture from 150°C to 240°C. 0.025 part of trimethyl phosphate was added to the obtained reaction product, and the reaction was allowed to proceed for 15 minutes. Then, 0.045 part of antimony trioxide was added, and after the reaction was allowed to continue for another 5 minutes, 0.025 part of trimethyl phosphate was added. 165 parts of the solution were added, and further 0.027 parts of 5-intermediate trimedel phosphate were added, and after 10 minutes, 0.001 parts of potassium nosate was added. Subsequently, the temperature was raised to 290°C, and a polycondensation reaction was carried out under a high vacuum of 0.2 mmt1g or less, resulting in an intrinsic viscosity of 0.60.
of polyethylene terephthalate was obtained. The volume resistivity of this polymer at 285°C is 8.0×106 Ω・
It was cm.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

Comparative Example 16 Calcium acetate monohydrate 0, 165 in Comparative Example 15
part was changed to 0.335 part of magnesium acetate tetrahydrate,
Polyethylene terephthalate having an intrinsic viscosity of 0.60 was prepared in the same manner as in Comparative Example 15 except that 0.027 part of trimethyl phosphate was not added. 285° of this polymer
The volume resistivity in C was 7.0×10 6 Ω·c+n.

When producing a polyester film using this polymer, the electrostatic castability and surface defects of the film will be discussed in 1 below.
As shown in the table.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for measuring polymer volume resistivity.

Claims (1)

[Claims] In the thermoplastic polyester produced by the transesterification method, there is no potassium element per 100 parts by weight of the polyester.
．． The amount of foreign matter is characterized by containing a potassium compound in a proportion of 0020 to 0.0072 parts by weight, and having a polymer volume resistivity of 7 x 10^6 to 4 x 10^7 Ωcm at 285°C. A polyester composition for film that has low and high-speed film forming properties.