JP2000044703A - Aromatic polyester film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface-defect-free film in high productivity by adding a sulfonic acid quaternary phosphonium salt in a specified amount based on the difunctional carboxylic acid component of the aromatic polyester after the polymerization reaction and imparting an electrical charge to the molten film in a non-contact manner just before the film reaches a rotary cooling drum. SOLUTION: An esterifiable-functional-group-containing sulfonic acid quaternary phosphonium salt represented by the formula is added in an amount of 0.1-45 mmol.%, based on the difunctional carboxylic acid component to an aromatic polyester after the polymerization reaction, the resulting mixture is extruded into a molten film having an alternating current volume resistivity of 6.5×108 Ω.cm or below, and this film is fed to a cooling rotary drum having a peripheral revolution speed of 60-150 m/min. Just before the molten film reaches the rotary drum, an electric charge is imparted to its surface in a non-contact manner to effect its close adhesion to the drum to obtain a film having a thickness of 10-1,000 μm. In the formula, A is an (n+2)-valent 2-18C aliphatic group or aromatic group; X1 and X2 are each hydrogen or an esterifiable functional group; (n) is 1 or 2; and R1 to R4 are each a 1-18C alkyl or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aromatic polyester film and a method for producing the same. For more information,
The present invention relates to a method for producing an aromatic polyester film having a uniform thickness with no surface defects under high productivity by bringing a molten film of an aromatic polyester into close contact with a rotary cooling drum and cooling it, and an aromatic polyester film thereby.

[0002]

2. Description of the Related Art Thermoplastic aromatic polyesters represented by polyethylene terephthalate have excellent physical and chemical properties, and are used in films for magnetic tapes, electrical insulation, capacitors, photography, packaging, etc. Widely used in the field.

[0003] A polyester film is usually produced by quenching a film-like melt melt-extruded from an extrusion die on the surface of a rotary cooling drum and then biaxially stretching it in the vertical and horizontal directions. In this case, in order to eliminate the surface defects of the film and increase the uniformity of the thickness, it is necessary to increase the adhesion between the film-like melt and the surface of the rotary cooling drum. As a method of increasing the adhesion, a wire-shaped electrode is provided between the extrusion die and the surface of the rotary cooling drum to precipitate an electrostatic charge on the surface of the film-like melt, and the film-like melt is placed on the surface of the cooling drum. A method of quenching while being in close contact (hereinafter referred to as an electrostatic casting method) is known (see Japanese Patent Publication No. 37-6142).

However, even in this electrostatic casting method, as the peripheral speed of the rotary cooling drum is increased to increase the productivity of the film, the adhesion of the film-like material to the surface of the cooling drum is reduced and the pin-shaped film is formed on the film surface. Induces defects and reduces thickness uniformity.

[0005] In film formation of a film, in particular, in film formation in a uniaxially or biaxially stretched film, it is important to improve the productivity and reduce the production cost, as well as to improve the quality of the film. For that purpose, the most effective method is to increase the peripheral speed of the rotary cooling drum to increase the film forming speed. Therefore, when the peripheral speed of the rotary 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, and the adhesion between the film-like material and the drum surface is reduced, and the film surface is reduced. In addition, a pin-like defect is induced, and the uniformity of the film thickness is reduced. For this reason, a method of increasing the voltage applied to the electrode to increase the amount of electrostatic charge deposited on the film-like material surface in order to increase the adhesion can be taken. An arc discharge occurs between the cooling drum and the surface of the cooling drum, and the film on the surface of the cooling drum is broken, and the surface of the cooling drum may be damaged. Therefore, it is practically impossible to increase the voltage applied to the electrode to a certain level or more, and there is a limit in obtaining a uniform film by improving the film forming speed of the conventional electrostatic casting method.

Japanese Patent Publication No. 53-40231 discloses a method for overcoming the limitations of the electrostatic casting method, improving the film forming speed, and producing a highly efficient polyester film having a uniform thickness and no surface defects. 0.005 to 1% by weight of alkali metal, alkaline earth metal or a compound thereof, preferably
0.07 to 0.3% by weight and the specific resistance of the molten polymer is 2 × 1
It proposes to improve the adhesion in the ^{0 7 ~5 × 10 8 Ω ·} cm. And as a specific example, lithium acetate
Add 0.15% by weight to increase specific resistance to 0.5 × 10 ⁸ Ω · cm, and add 0.09% by weight of strontium acetate to increase specific resistance to 2 ×
It is shown to be 10 ⁸ Ω · cm.

In Japanese Patent Publication No. 56-15730, when an alkali metal compound or an alkaline earth metal compound is added by a direct polymerization method, the by-product amount of diethylene glycol (DEG) increases, and the melting point of the produced polyester decreases. However, since the film tends to stick to the casting drum, the film is more likely to be torn during stretching, and the like, problems occur, such as a method for producing a polyester with a small amount of DEG by-product and improved electrostatic application castability. After the esterification reaction is substantially completed, Zn, Mg, a metal compound selected from the Mn compound and a phosphorus compound are represented by the following formula:

[0008]

20 ≦ M ≦ 1000 0.8 ≦ M / P ≦ 5 (where M represents the total metal atomic weight (ppm) of the metal compound with respect to the polyester, and M / P represents the molar ratio of the total metal compound to phosphorus. It is proposed to add satisfactorily, and then to carry out polycondensation.

In Japanese Patent Application Laid-Open No. 59-62627, as a method for improving the above-mentioned troubles of the direct polymerization method, when a polyester having a main repeating unit of ethylene terephthalate is produced by the direct polymerization method, it is required to prepare the polyester before starting the esterification. Mg
30 to 400 ppm based on polyester with compound as Mg atom
Between the point at which the esterification rate has progressed at least 91% and the end of the initial overall reaction,
a, the alkali metal compound of the K compound is represented by the following formula:

[0010]

1.2 ≦ Mg / P ≦ 2.0 3.0 ≦ M ≦ 50 (wherein Mg / P is the atomic ratio of Mg atoms to P atoms, and M is the amount of the alkali metal compound added to the polyester as a metal atom (ppm) ) Is suggested to be added so as to satisfy).

Further, it is difficult to produce a high-quality film which completely satisfies the requirements of the market at a high casting speed by using a polyester raw material obtained by a conventionally known method. If it is attempted to lower the particle size, coarse particles will inevitably precipitate, making it difficult to completely suppress the decrease in transparency.

Japanese Patent Application Laid-Open No. 59-62626 discloses a method for improving this point, in which a P compound, a Ca compound, and a Na, K compound are used when the esterification rate in a direct polymerization method reaches 91% or more. The selected alkali metal compounds in these order and the following formula

[0013]

## EQU3 ## 50 ≦ Ca ≦ 400 1.2 ≦ Ca / P ≦ 3.0 3.0 ≦ M ≦ 20 (wherein the addition amount (ppm) of a Ca compound as a Ca atom to a polyester, Ca / P is a ratio of a Ca atom and a P atom Atomic ratio of
M indicates the amount (ppm) of the alkali metal compound added as a metal atom to the polyester. ) Is proposed to satisfy the above.

According to Japanese Patent Publication No. Sho 61-40538, it is necessary to add a large amount of an alkali metal compound or an alkaline earth metal compound in order to reduce the specific resistance of a molten polyester. The coarsened particles may cause pinholes in the film, etc., or may cause arc discharge during film formation, and may significantly deteriorate the color tone of the polyester film itself, resulting in a strong yellowish polyester. Since it is not preferable because a film is obtained, 0.01 to 2% by weight of an inorganic fine powder and 0.01% by weight of an ethylene glycol-soluble alkali metal compound
It is proposed that the content be 01 to 0.0025% by weight.

All of the above-mentioned proposals increase the amount of charge on the surface of the film by reducing the specific resistance of the molten polyester. However, there is a limit in improving the electrostatic adhesion by lowering the specific resistance.

JP-A-62-187724 and JP-A-62-18
No. 9133 discloses that the maximum casting speed greatly increases as the specific resistance decreases to about 0.2 × 10 ⁸ Ωcm in the specific resistance, but the specific resistance is 0.2 × 10 ^{8 in} the region where the maximum casting speed is 50 m / min or more. In the region of Ωcm or less, the maximum casting speed changes greatly with a slight decrease in the specific resistance, so that the difference in specific resistance between 70 m / min and 80 m / min is only 0.01 m / min.
It is described as × 10 ⁸ Ω · cm, and the correlation between the maximum casting speed and the specific resistance becomes extremely poor. JP-A-62-187724 and JP-A-62-189133 use a polymer in which the initial accumulated charge amount of the molten polyester is 2.9 μc / mm ² or more, and use Mg as a means for increasing the initial accumulated charge.
The compound and the P compound are represented by the following formula

[0017]

## EQU4 ## 30 ≦ Mg ≦ 400 0.8 ≦ Mg ≦ P ≦ 3 (wherein the content (ppm) of Mg compound as Mg atom with respect to polyester, Mg / P indicates the atomic ratio of Mg atom to P atom. ), And further, these compounds and C
It is proposed to combine at least one of o, Na, K, and Zr compounds in a specific ratio.

However, also in this case, as described above, in order to increase the initial accumulated charge amount, Mg, P compounds, Na, K,
Since Co and Zr compounds are used, it is difficult to avoid an increase in coarse particles and a deterioration in polymer color tone due to an increase in the amount of these compounds.

On the other hand, Japanese Patent Publication No. 47-22334 discloses the following formula:

[0020]

Embedded image Wherein A is an aliphatic group or an aromatic group, Y ¹ is a carboxylate ester-forming group, Y ² is the same group as Y ¹ , hydrogen or a halogen atom, and R ¹ , R ² , R ³ and R ⁴ are groups selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and a hydroxyalkyl group, and l is a natural number.) There has been proposed a method of producing a polyester having improved dyeability with respect to a basic dye by adding it at 10% by weight or less.

US Pat. No. 3,732,183 describes the following formula:

[0022]

Embedded image

Wherein R is an alkyl group such as CH ₃ , C
_{2 H 5, n-C 3} H 7, n-C 4 H 9, 3-sodium (sulfopropyl) group and 4-sodium (sulfobutyl) group. A filament-forming aromatic polyester dyeable with a cationic dye, which contains the sulfonate group represented by the formula (1) in an amount of 0.5 to 5 mol% based on the constitutional unit of the polyester.

In Japanese Patent Publication No. 1-25005, the following formula

[0025]

Embedded image

Wherein A is an alkyl or alkenyl group having 4 to 18 carbon atoms, a phenyl group, a phenyl group substituted with alkyl having 1 to 18 carbon atoms, a naphthyl group or
A naphthyl group substituted with an alkyl of 18; and
R ¹ , R ² , R ³ and R ⁴ are the same or different and have 1 to 18 carbon atoms
Or a hydrocarbon group having 1 to 18 carbon atoms having a substituent. Are proposed as antistatic agents for polymer materials. The publication discloses polyethylene terephthalate as a polymer material,
It is recommended that the antistatic agent be added in an amount of 0.1 to 10% by weight.

Further, the following publication also discloses the above-mentioned JP-B-47-223.
No. 34, U.S. Pat.No. 3,732,183 and Japanese Patent Publication No.
-29500 discloses a cationic dye dyeable polyester fiber using the same compound as the phosphonium phosphonium salt disclosed in JP-A-29500.

EP-A-0280026 discloses that
The following formula

[0029]

Embedded image

Wherein A is an aromatic or aliphatic group;
X ¹ is a hydrogen atom or an ester-forming group, X ² is the same or different ester-forming group as the ester-forming group of X ¹ , and R ¹ , R ² , R ³ and R ⁴ are independently of each other An alkyl group or an aryl group, and n is an integer of 1 or more. ) Is added to the phosphonium sulfonate represented by 0.1).
Aromatic polyester fibers containing at 〜10 mole% are disclosed.

JP-A-1-103650 discloses that a polyester modified with the same phosphonium sulfonate salt of 0.05 to 20 mol% as described in the above-mentioned European Patent Application Publication No. A method is disclosed in which 0.002 to 2 mol% of an alkali metal salt or alkaline earth metal salt of an acid is blended to produce a cationic dye dyeable polyester composition having excellent heat resistance during melt spinning.

JP-A-1-103623 discloses the above-mentioned JP-A-1-103623.
In the 103650 publication, in place of the metal salt of the organic carboxylic acid, the following formula

[0033]

HOOC-B-CCOH (where B is

[0034]

Embedded image

Is as follows. A) discloses a method of blending 0.1 to 50 mol% of the aromatic dicarboxylic acid represented by the formula (1) to produce a cationic dye dyeable polyester which is also excellent in heat resistance during melt spinning.

JP-A-1-192823 discloses the above-mentioned JP-A-1-192823.
The same sulfonate phosphonium salt as in the above general formula disclosed in JP 103650, 0.01 to 20 mol%, the following general formula

[0037]

(RSO ₃ ) nM (wherein, R is an alkyl group, aryl group or aralkyl group having 6 or more carbon atoms, M is an alkali metal or alkaline earth metal, and n is 1 or 2) 0.05 to 10% by weight of a sulfonic acid metal salt represented by the following formula) and 0.05 to 10% by weight of a polyoxyalkylene glycol and / or a derivative thereof.
A polyester composition containing is disclosed. According to the description of the publication, the polyester composition prevents generation of static electricity during melt molding and gives excellent moldability.

Japanese Patent Application Laid-Open No. 1-197523 discloses the above-mentioned Japanese Patent Application Laid-Open No.
The same sulfonate phosphonium salt as in the above general formula disclosed in JP 103650, 0.005 to 0.495 mol%, and the following formula

[0039]

Embedded image (Wherein, Z ₁ is an aromatic group or an aliphatic group, A ₁ is an ester-forming functional group, A ₂ is the same or different ester-forming functional group as A ₁ or a hydrogen atom , M is a metal atom and m is a positive integer.) 0.005 to 0.495 mol% of a sulfonic acid metal salt represented by the following formula: A method for producing a modified polyester having excellent moldability and color tone has been proposed.

Now, in the magnetic recording medium which is a main use of the biaxially stretched polyester film, the film has a high smoothness due to a recent increase in recording density or a rise in video quality. For example, the presence of the above-mentioned coarse particles that cause dropout significantly reduces the film quality. Further, according to the research results of the present inventor, in a polymer containing a large amount of an alkali metal compound, an alkaline earth metal compound or a phosphonium sulfonate, a large number of foreign substances are present in the film. Among them, the black foreign matter is mainly an antimony compound, and appears to be a substance obtained by reducing and depositing antimony oxide used as a polymerization catalyst for polyester. The foreign matter will significantly reduce the product quality of the film.

As a method of producing a high-quality film at a high speed while suppressing the generation of foreign substances, Japanese Patent Publication No. 7-5765 discloses that a bifunctional carboxylic acid component has 0.1 to 45 mmol% of an ester-forming functional group. The quaternary phosphonium salt of sulfonic acid is contained in the polymer chain or the quaternary phosphonium salt of sulfonic acid having no ester-forming functional group is dispersed and contained in the polymer, and the value of the AC volume resistivity of the molten film Is 6.5
A method using an aromatic polyester film having a density of × 10 ⁸ Ω · cm or less has been proposed, and the quaternary phosphonium salt of sulfonic acid having an ester-forming functional group is represented by the following formula.

[0042]

Embedded image

Wherein A is an n + divalent aliphatic group or aromatic group having 2 to 18 carbon atoms, X ₁ and X ₂ are the same or different and are a hydrogen atom or an ester-forming functional group, Is 1 or 2, and R ₁ , R ₂ , R ₃ and R ₄ are the same or different and are an alkyl group having 1 to 18 carbon atoms, a benzyl group or an aryl group having 6 to 12 carbon atoms. X ₁ and X ₂ are not simultaneously hydrogen.)

The sulfonic acid quaternary phosphonium salt having no ester-forming functional group is represented by the following formula.

[0045]

Embedded image

Wherein A ′ is an m-valent aliphatic group or aromatic group having 4 to 18 carbon atoms, and R ₅ , R ₆ , R ₇ and R ₈ are each independently 1818 monovalent hydrocarbon groups, and m is 1 or 2.)

According to the method described in Japanese Patent Publication No. 7-5765, an aromatic polyester film having high productivity and uniform thickness without surface defects can be obtained by adding a small amount of phosphonium sulfonate. Describes a method of adding a phosphonium salt in a polymer polymerization step in order to contain a phosphonium sulfonate salt in a polymer chain of an aromatic polyester, which will increase the production brand of the polymer. . An increase in the number of polymer species causes an increase in capital investment due to complicated production processes and an increase in related equipment such as storage tanks. In addition, as the coexistence time of the quaternary phosphonium salt of sulfonic acid and the molten polyester increases, the generation of foreign substances increases. When a film is molded from a molten polyester, the sublimable pyrolyzate of the polymer increases, and the sublimate adheres to a discharge electrode that imparts a charge to the film, and the discharge function of the discharge electrode is increased. And the like.

The present inventors have solved these problems by shortening the coexistence time of the quaternary phosphonium salt of sulfonic acid and the molten polyester, and without increasing the capital investment and complicating the production process. Furthermore, they have found that a higher quality film with less foreign matter can be produced with high productivity, and have reached the present invention.

[0049]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aromatic polyester film and a method for producing the same. Another object of the present invention is to provide a method for producing an aromatic polyester film having no surface defects and having a uniform thickness while achieving high productivity by closely contacting a molten film of an aromatic polyester on a rotary cooling drum and cooling it, and An object of the present invention is to provide the film. Still other objects and advantages of the present invention will be apparent from the following description.

[0050]

According to the present invention, the above objects and advantages of the present invention include: first, extruding a molten film of a thermoplastic aromatic polyester onto a rotating cooling drum;
Then, the film is brought into close contact with the rotating drum and cooled to produce a film of an aromatic polyester, wherein the aromatic polyester has an ester-forming functionality of 0.1 to 45 mmol% based on a difunctional carboxylic acid component. A quaternary phosphonium salt of a sulfonic acid having a group is added to the aromatic polyester after the polymerization reaction, and the value of the AC volume resistivity (F / D value) of the molten film is 6.5 × 10 ⁸ Ω · cm or less. Using a polyester and non-contactly charging the molten surface of the aromatic polyester in the vicinity (immediately before) the molten film of the aromatic polyester reaches the rotating cooling drum. Is done.

The quaternary phosphonium salts of sulfonic acid having an ester-forming functional group include, for example,

[0052]

Embedded image

Wherein A is an n + divalent aliphatic or aromatic group having 2 to 18 carbon atoms, X ¹ and X ² are the same or different and are a hydrogen atom or an ester-forming functional group,
And n is 1 or 2, and R ¹ , R ² , R ³ and R ⁴ are the same or different and are an alkyl group having 1 to 18 carbon atoms, a benzyl group or an aryl group having 6 to 12 carbon atoms. ,
However, a compound represented by the formula wherein X ₁ and X ₂ are not simultaneously hydrogen is preferably used.

In the above formula, A is an aliphatic group or aromatic group having 2 to 18 carbon atoms such as n + 2, for example, trivalent (when n = 1), tetravalent or (when n = 2). is there.

Examples of the aliphatic group include those having 2 to 10 carbon atoms.
Of these, a linear or branched, saturated or unsaturated hydrocarbon group is preferred.

As the aromatic group, an aromatic group having 6 to 18 carbon atoms is preferable, and for example, a trivalent or tetravalent benzene skeleton, a naphthalene skeleton or a biphenyl skeleton is more preferable. Such aromatic groups are X ₁ ,
In addition to X ₂ and sulfonic acid quaternary phosphonium salt, for example it may be substituted by an alkyl group having 1 to 12 carbon atoms.

X ₁ and X ₂ can be the same or different and are hydrogen or an ester-forming functional group. X ₁ and
If X ₂ is simultaneously hydrogen, it will lack a group to be copolymerized in the polyester chain. X ₁ and X ₂ cannot both be hydrogen atoms at the same time, and at least one must be an ester-forming functional group.

Examples of the ester-forming functional group include, for example,

[0059]

Embedded image

And the like. Of these groups,
R ′ is a lower alkyl group having 1 to 4 carbon atoms or a phenyl group, 1 is an integer of 2 to 10, p is an integer of 2, 3 or 4, and q is an integer of 1 or more, for example, 1 to It is an integer of 100.

The lower alkyl group for R 'may be linear or branched, and may be, for example, methyl, ethyl,
Preferred examples include n-propyl, iso-propyl, n-butyl, sec-butyl and the like. n is 1
Or an integer of 2.

The groups R ₁ , R ₂ , R ₃ and R ₄ constituting the portion of the phosphonium sulfonate base are the same or different from each other and are an alkyl group having 1 to 18 carbon atoms, a benzyl group or a group having 6 to 6 carbon atoms. 12 aryl groups.

The alkyl group having 1 to 18 carbon atoms may be linear or branched. For example, methyl,
Ethyl, propyl, butyl, dodecyl, stearyl and the like can be mentioned. Preferred examples of the aryl group having 6 to 12 carbon atoms include phenyl, naphthyl, biphenyl and the like. The phenyl moiety of these aryl or benzyl groups is, for example, a halogen atom,
It may be substituted with a nitro group or a lower alkyl group having 1 to 4 carbon atoms.

Preferred specific examples of the quaternary phosphonium sulfonic acid salt include tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate, ethyltributylphosphonium 3,5-dicarboxybenzenesulfonate, and 3,5-dicarboxybenzenesulfonate. Carboxybenzenesulfonic acid benzyltributylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid phenyltributylphosphonium salt, 3,5-
Tetraphenylphosphonium dicarboxybenzenesulfonate, ethyltriphenylphosphonium 3,5-dicarboxybenzenesulfonate, butyltriphenylphosphonium 3,5-dicarboxybenzenesulfonate,
3,5-dicarboxybenzenesulfonic acid benzyltriphenylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid tetrabutylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid ethyltributylphosphonium salt, 3,5-di Carbomethoxybenzenesulfonic acid benzyltributylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid phenyltributylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid tetraphenylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid Ethyl triphenyl phosphonium salt, 3,5-dicarbomethoxybenzene sulfonic acid butyl triphenyl phosphonium salt, 3,5-dicarbomethoxy benzene sulfonic acid benzyl triphenyl phosphonium salt, 3-carboxy benzene sulfone Tetrabutylphosphonium salt, 3-carboxybenzenesulfonic acid tetraphenylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetrabutylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetraphenylphosphonium salt, 3,5-di (β-hydroxyethoxy Carbonyl)
Tetrabutylphosphonium benzenesulfonate, 3,5
Tetraphenylphosphonium salt of di (β-hydroxyethoxycarbonyl) benzenesulfonic acid, tetrabutylphosphonium salt of 3- (β-hydroxyethoxycarbonyl) benzenesulfonic acid, tetraphenylphosphonium salt of 3- (β-hydroxyethoxycarbonyl) benzenesulfonic acid Tetrabutylphosphonium salt of 4-hydroxyethoxybenzenesulfonic acid, bisphenol A-3,
3'-di (tetrabutyl phosphonium sulfonate),
2,6-dicarboxynaphthalene-4-sulfonic acid tetrabutylphosphonium salt, α-tetrabutylphosphonium sulfosuccinic acid and the like can be mentioned. The above quaternary phosphonium salts of sulfonic acid may be used alone or in combination of two or more.

Such a quaternary phosphonium sulfonic acid salt is generally prepared by a reaction known per se between a corresponding sulfonic acid and a phosphine or a reaction known per se between a corresponding metal salt of a sulfonic acid and a quaternary phosphonium halide. Can be easily manufactured.

As described above, the aromatic polyester targeted in the present invention can be obtained by converting the quaternary phosphonium salt of sulfonic acid added after the polymerization reaction of the aromatic polyester into a bifunctional carboxylic acid constituting the polymerization of the aromatic polyester. It is present in as little as 0.1 to 45 mmol%, preferably in an even smaller amount of 0.2 to 20 mmol%, based on the acid component. This is because the aromatic polyesters targeted in the present invention are different from, for example, modified polyesters containing a quaternary phosphonium sulfonic acid salt in an amount sufficient to be a dyeing seat for a cationic dye, and the like. The decrease in the physical properties of the aromatic polyester due to the inclusion of the salt, such as a decrease in the softening point, is substantially negligible, and is substantially comparable to the physical properties of the aromatic polyester not containing the quaternary phosphonium salt of sulfonic acid. It shows that it shows physical properties.

The aromatic polyester to be used in the present invention is an aromatic polyester having an aromatic dicarboxylic acid component as a main dicarboxylic acid component and an alkylene glycol having 2 to 10 carbon atoms as a main diol component, for example, polyethylene terephthalate, Copolyesters containing polyethylene-2,6-naphthalate or ethylene terephthalate as a main repeating unit and copolyesters containing ethylene-2,6-naphthalate as a main repeating unit are particularly preferred.
Examples of the copolymerization component of the copolyester include aromatic dicarboxylic acids such as isophthalic acid and aliphatic dicarboxylic acids such as adipic acid; oxycarboxylic acids such as oxybenzoic acid; trimethylene glycol, tetramethylene glycol, and 1,4- Examples thereof include aliphatic dihydroxy compounds such as cyclohexanedimethanol; and polyoxyalkylene glycols such as polyethylene glycol and polybutylene glycol. Further, as long as the aromatic polyester is substantially linear, a polycarboxylic acid such as trimellitic acid and pyromellitic acid, and a polyol such as glycerin, trimethylolpropane and pentaerythritol can be used. The thermoplastic aromatic polyester may contain additives such as a stabilizer and a colorant, and may contain or contain a lubricant such as inorganic fine particles and organic fine particles for improving the slipperiness.

[0068] Such a thermoplastic aromatic polyester can be produced by a known method. For example, if polyethylene terephthalate is taken as an example for convenience, terephthalic acid and ethylene glycol are usually directly esterified, or a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol. A first-stage reaction for producing a glycol ester of terephthalic acid and / or a low-polymer thereof by reacting or adding terephthalic acid to ethylene oxide, and heating the reaction product of the first stage under reduced pressure To a polycondensation to a desired degree of polymerization. At this time, additives such as a catalyst can be optionally used as needed.

In order to add the quaternary phosphonium salt of sulfonic acid to the aromatic polyester after the polymerization reaction, the quaternary phosphonium salt of sulfonic acid can be added to the aromatic polyester in any step until the aromatic polyester is melt-extruded from a die, for example, the polymerization of polyester It can be added in a step after the reaction, a drying step, a pre-extrusion treatment step and the like.

As another method, for example, an aromatic polyester to which a quaternary phosphonium salt of sulfonic acid is added in a relatively large amount after a polymerization reaction is separately prepared in an optional step until melt extrusion from the die. An aromatic polyester not containing or containing a relatively small amount of a quaternary phosphonium salt of sulfonic acid was used in such a manner that the proportion of the quaternary phosphonium salt of sulfonic acid in the resulting mixture would be the predetermined ratio specified in the present invention. And a method of mixing.

The aromatic polyester to be used in the present invention has a composition containing a quaternary phosphonium salt of a sulfonic acid dispersed in a proportion of 0.1 to 45 mmol% as described above, and the alternating current of the molten film is also included. Volume resistivity value (F /
D value) is 6.5 × 10 ⁸ Ω · cm or less.

According to the study of the present inventors, the AC volume resistivity of the molten film is more closely related to the amount of charge that can be applied to the surface of the aromatic polyester molten film than to the DC volume resistivity of the molten film. Aromatic polyester with an AC volume resistivity value (F / D value) of 6.5 × 10 ⁸ Ωcm or less of the molten film has a sufficient charge amount to adhere to the cooling drum that rotates relatively quickly. It was revealed that it can be provided.

The aromatic polyester to be used in the present invention preferably has a value of the AC volume resistivity (F / D value) of the molten film in the range of 3.2 × 10 ^{8 to} 5.6 × 10 ⁶ Ω · cm. Moreover, the aromatic polyester targeted in the present invention preferably has an intrinsic viscosity of 0.45 to 0.75.

The ratio of the copolymerization bond between the quaternary phosphonium sulfonic acid salt and the aromatic polyester is affected by the melting temperature and the time of melt kneading after the quaternary phosphonium sulfonic acid salt is added to the aromatic polyester. The higher the temperature and the longer the time, the higher the proportion of copolymerized bonds. The proportion of its copolymerized bonds is in the range of 10-99.9%,
Preferably it is in the range of 50 to 99.9%, more preferably 70 to 99.9%.

The amount of the quaternary phosphonium sulfonic acid salt is 45.
At a high concentration of more than mmol%, in addition to increasing the generation of foreign matter in the film, the compound adheres to the rotating cooling drum during film formation and accelerates the contamination rate of the drum,
Drum cleaning tends to cause problems such as a decrease in production efficiency, which is not preferable.

In the method of the present invention, a melt of the aromatic polyester as described above is extruded through a slit onto a rotary cooling drum to a thickness of, for example, 10 to 1,000 μm, and then the film is uniformly brought into close contact with the cooling drum. This is performed by cooling the film on a cooling drum. The molten film extruded onto the rotary cooling drum forcibly applies electric charges from an electrode provided in a space 3 to 10 mm away from the film surface in a non-contact manner in the vicinity (immediately before) reaching the drum. Is done.

As described above, the aromatic polyester targeted by the present invention is prepared by adding a quaternary phosphonium sulfonic acid salt in an amount of 0.1 to 45 mmol% after completion of the polymerization reaction and 6.5 × 10 ⁸ Ω.
-Shows the AC volume resistivity of the melted film of less than cm, and evenly adheres to the cooling drum that rotates relatively fast due to the application of such charge. A device for applying electric charge from the electrode and a device for a cooling drum combined therewith are disclosed in, for example, Japanese Patent Publication No. 37-6142.

The rotational speed of the cooling drum can be so high that the peripheral speed is, for example, at least 50 m / min. A preferred rotational peripheral speed can be in the range of 60 to 200 m / min.

The cooling surface of the cooling drum that receives the molten film of aromatic polyester can be, for example, a mirror surface and can have a large number of channel-like microcracks as in the cooling drum disclosed in US Pat. No. 4,478,772. It can be the face you have.

When a cooling drum having a mirror-finished cooling surface is used, it is advantageous to set the rotation peripheral speed of the cooling drum in the range of 60 to 150 m / min. When using a cooling drum whose cooling surface is a surface having a large number of channel-like microcracks, the rotation peripheral speed of the cooling drum is 80 to 20.
Advantageously, it is in the range of 0 m / min.

Further, on the cooling surface of the rotating cooling drum, a liquid film containing water as a main component may be provided between the cooling surface and the surface of the aromatic polyester melt film. Such methods for providing a liquid coating are known per se, for example, from French Patent 2,049,046 and
It is disclosed in, for example, JP-A-9-99160.

As described above, the present invention can be applied to other improved methods based on the electrostatic adhesion method, and has the effect of further improving the rotational peripheral speed of the rotating drum.

According to the method of the present invention, the cooled and solidified film obtained by leaving the rotary cooling drum can be subjected to a method known per se, for example, then to uniaxial stretching or biaxial stretching.
It is axially stretched or wound once and then subjected to biaxial stretching, and is used in various fields.

According to the study of the present inventor, instead of the aromatic polyester, 0.1 to the bifunctional carboxylic acid component was used.
In addition to adding a quaternary phosphonium salt of a sulfonic acid having an ester-forming functional group of ~ 45 mmol% to the aromatic polyester after the completion of the polymerization reaction, 0.1-20 mmol% of an alkali metal or alkaline earth based on the bifunctional carboxylic acid component is further added. The object of the present invention is similarly achieved by using an aromatic polyester containing a compound of a class of metals and having a value of AC volume resistivity (F / D value) of 6.4 × 10 ⁸ Ω · cm or less in the molten film. It was revealed to be.

Therefore, according to the present invention, second, a molten film of a thermoplastic aromatic polyester is extruded onto a rotating cooling drum, and then the film is brought into close contact with the rotating drum and cooled to form a film of the aromatic polyester. A method for producing a film, wherein the quaternary phosphonium sulfonic acid salt is added to the polyester as the aromatic polyester after the completion of the polymerization reaction to contain a compound of an alkali metal or an alkaline earth metal, and the AC volume of the molten film is changed. An aromatic polyester having a resistivity value of 6.4 × 10 ⁸ Ωcm or less is used, and in the vicinity of the molten film of the aromatic polyester reaching the rotating cooling drum, the non-contact with the molten surface of the film is performed. Provided is a method for producing an aromatic polyester film, which imparts a charge.

Examples of the alkali metal or alkaline earth metal include, for example, lithium, sodium, potassium, magnesium, calcium, cesium, strontium, barium, rubidium, beryllium and the like. Examples of these compounds include oxides, chlorides, hydrides, hydroxides, sulfides, sulfates, carbonates, acid salts, and carboxylate salts of such elements. More specifically, for example, magnesium oxide, calcium oxide, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, calcium chloride, strontium chloride, magnesium chloride, calcium hydride,
Strontium hydride, magnesium hydride, lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium sulfate , Potassium sulfate,
Magnesium sulfate, calcium sulfate, barium sulfate, sodium carbonate, potassium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, lithium acetate, sodium acetate, Potassium acetate, rubidium acetate, cesium acetate, beryllium acetate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, sodium benzoate, potassium benzoate, rubidium benzoate,
Examples include cesium benzoate, magnesium benzoate, calcium benzoate, strontium benzoate, barium benzoate, sodium phthalate, potassium phthalate, calcium phthalate, magnesium phthalate, barium phthalate, calcium terephthalate, and barium terephthalate. it can. One or more of these can be used.

These compounds can be added, for example, by dissolving or dispersing them in ethylene glycol, or as they are, all at once or in several portions into a reaction system for producing an aromatic polyester.

When these compounds are used by dispersing them in glycol, the particles preferably have a particle size of 5 μm or less, more preferably 3 μm or less. The timing of addition may be at any stage during the production of the polyester as long as a good dispersion state can be obtained in the aromatic polyester.

These compounds are added to an aromatic polyester not containing a quaternary phosphonium salt of sulfonic acid, and then a quaternary phosphonium salt of sulfonic acid is added before film formation to form an aromatic polyester used for film formation. It is preferable to use a method in which a quaternary phosphonium salt of a sulfonic acid and a compound of an alkali metal or an alkaline earth metal are set to predetermined values.

The compound of the alkali metal or alkaline earth metal is preferably 0.1 to 20 mmol%, more preferably 0.1 to 20 mmol%, based on the bifunctional carboxylic acid component (excluding the sulfonic acid salt) constituting the aromatic polyester. 0.2 to 18 mmol%.

When the alkali metal or alkaline earth metal compound is used together with the quaternary phosphonium sulfonic acid salt, the thermal stability of the polyester is further improved, and the film can be produced with higher efficiency, although the reason is not clear. be able to. When the amount of these compounds added is less than 0.1 mmol%, the benefit of adding these compounds is not clear, while in the region where the amounts of these compounds added exceeds 20 mmol%, the heat stability of the polyester obtained is no longer obtained. The improvement effect is saturated, and it is difficult to exhibit the effect more than when 20 mmol% is added. There seems to be no specific ratio between the addition ratio of the quaternary phosphonium sulfonic acid salt and the addition amount of the alkali metal or alkaline earth metal compound, which is particularly effective. However, the addition amount of the quaternary phosphonium salt of sulfonic acid is 0.1 to 45 mmol%.
When the addition amount of the alkali metal or alkaline earth metal compound exceeds 20 mmol%, the surface defects of the produced film and the amount of black foreign matter containing antimony as a main component increase.

In the present invention, the aromatic polyester preferably has a DC volume resistivity value (P / D value) of 1.5 × 10 ^{8 to} 4.0 × 10 ⁹ Ω · cm at 285 ° C. .

In the method of the present invention using the aromatic polyester containing a compound of an alkali metal or an alkaline earth metal, the cooling drum is preferably rotated at a peripheral speed of at least 60 m / min, more preferably 60 to 200 m / min. It is advantageous to rotate it.

It is to be understood that the description of the portions not described in the second method of the present invention is the same as that of the first method of the present invention.

According to the first and second methods of the present invention described above, the molten film of the aromatic polyester can be brought into close contact with the cooling drum even when the cooling drum rotates relatively quickly. It is possible to produce a film with excellent quality while achieving high productivity.

Thus, according to the present invention, an aromatic polyester of excellent quality, produced by the first and second methods, free of surface defects and black matter containing antimony as a main component and having a uniform thickness. A film is provided.

The film which can be produced by these methods has a higher electrical performance with respect to alternating current than a film obtained from an aromatic polyester containing a sulfonate sodium salt having an ester-forming functional group in a polymer chain. Are distinctive in that they differ significantly.

Therefore, according to the present invention, the aromatic polyester is (1) a sulfonic acid having an ester-forming functional group in a proportion of 0.1 to 45 mmol% based on the bifunctional carboxylic acid component constituting the aromatic polyester. A quaternary phosphonium salt is added after the completion of the polymerization reaction, or (1) ′ is added to the difunctional carboxylic acid component constituting the aromatic polyester in an amount of 0.1%.
A quaternary phosphonium sulfonic acid salt having an ester-forming functional group in a proportion of 1 to 45 mmol% is added after the polymerization reaction, and 0.1 to 20 mmol% based on a difunctional carboxylic acid component constituting the aromatic polyester. And (2) the ester forming property in the relationship between the film AC volume resistivity and the film DC volume resistivity in the molten state. An aromatic polyester characterized by exhibiting a smaller value of AC volume resistivity at the same value of DC volume resistivity than an aromatic polyester containing a sulfonic acid sodium salt having a functional group in a polymer chain, A film is provided.

Among the above films, those in which the aromatic polyester is mainly composed of ethylene terephthalate or ethylene-2,6-naphthalate are preferred. Further, as described above, the quaternary phosphonium salt of sulfonic acid is, for example, of the following formula:

[0100]

Embedded image

(Wherein X ₁ , X ₂ , A, R ₁ , R ₂ , R ₃ , R ₄ and n have the same definitions as above).

Regarding the requirement (2) of the film of the present invention, at the same value of the DC volume resistivity, the film of the present invention has an AC volume resistivity of about 1/2 to less than that of the comparative film. Advantageously, it is reduced to a value of 1/10.

The aromatic polyester film of the present invention and the aromatic polyester film produced by the method of the present invention are suitably used in the field of films such as magnetic tape applications, electrical insulation applications, capacitor applications, photographic applications, packaging applications, and the like. You.

[0104]

The present invention will be further described below with reference to examples. In the examples, `` parts '' means parts by weight, and the intrinsic viscosity and melting point of polyester, electrostatic castability, volume resistivity of polymer and film, surface defects of film and the like are measured and evaluated by the following methods. Got it.

1. Intrinsic Viscosity The viscosity was measured at 35 ° C. using o-chlorophenol as a solvent.

2. Melting point of polymer Measured at a heating rate of 10 ° C./min by a differential calorimeter (DSC).

3. Electrostatic Casting When applying a voltage of 7000V between the cooling drum and the electrode near the base for melt-extruding the polymer into a film and at the top of the extruded film, casting is performed. The maximum speed of the cooling drum capable of stably forming a film without causing pin-shaped defects (pinner bubbles) and reducing the uniformity of the thickness was determined.

4. Defects on Film Surface This is an evaluation of particulate foreign matter produced as a by-product during the extrusion process from the polymerization of thermoplastic polyester. The molten polymer is extruded at a temperature of melting point + 35 ° C., closely adhered to a rotary cooling drum, and cooled. To obtain an amorphous film, and then vertically
The film was stretched 3.6 times and 3.9 times in the transverse direction to produce a film having a thickness of 15 μm.

The film was observed using a phase-contrast microscope, and the number of particles having a maximum length of 5 μm or more in the microscope image was counted using an image analyzer Luzex 500 (manufactured by Nippon Regulator). Particles having a particle diameter of 5 μm or more and a particle number of 10 / cm ² or less can be practically used.

5. Thermal Stability of Polymer In the measurement of film surface defects described in item 4, evaluation was made based on the difference between the intrinsic viscosity of the thermoplastic polyester chip and the intrinsic viscosity of the film after melt extrusion cooling.

When the value was 0.052 or less, the thermal stability was evaluated as good, and when the value was greater than 0.052, the thermal stability was evaluated as poor.

6. Measurement of Film Volume Resistivity Measurement was performed using the apparatus shown in FIG. As the measurement sample 1, a film having a thickness of about 150 μm is used. An upper electrode 3 with a diameter of 5.6 cm and a thickness of 0.2 cm that can hold a parallel gap of 150 μm is placed on the upper surface of a cylindrical lower electrode 2 with a diameter of 20 cm, and the measurement sample 1 is inserted so as to be in close contact with the electrode. I do.

The lower electrode 2 has a built-in heating device 4 and a temperature detecting end 5. The variation of the surface temperature of the lower electrode 2 on the measurement surface is within 1 ° C., and the temperature difference between the lower end 2 and the detecting end is 8 ° C./min. At 2 ° C. or less. The detected temperature is measured by the reading thermometer 7. The entirety of the electrode is placed in the heat insulation box 11. Adjust the voltage regulator 6 to adjust the heating rate.

The power supply 8 applies the generated voltage between the two electrodes via the standard resistor 9. The power supply is a power supply for generating 100 V DC when measuring the DC volume resistivity of the film. 100V to measure the AC volume resistivity of
This is a power supply that generates 50Hz. As for the current flowing through this circuit, the voltage generated across the standard resistor 9 is read by an electron meter 10 having an internal impedance of 100 MΩ or more.

In the present invention, the measurement of the AC volume resistivity of the film at the time of melting was carried out by measuring the temperature of the lower electrode at a rate of 8 ° C./min.
The measurement is performed at a temperature of 0 ° C., and the AC volume resistivity Z is obtained from the following equation from the applied voltage E, the current I, the electrode area S, and the electrode interval d.

[0116]

(Equation 5)

Example 1 To a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol was added 0.038 part of manganese acetate tetrahydrate, and the ester exchange reaction was carried out while gradually raising the temperature from 150 ° C. to 240 ° C. Natsuta Intermediate reaction temperature 170
At the time of temperature reached 0.040 parts of antimony trioxide,
Further, 0.2 part of spherical silica having an average particle diameter of 0.6 μm was added.
Subsequently, a transesterification reaction is performed. After the transesterification reaction, trimethyl phosphate is added to ethylene glycol in 13 g.
A solution (0.049 part in terms of trimethyl phosphate) that had been heat-treated at 5 ° C for 5 hours under a pressure of 1.1 to 1.6 kg / cm ² was added.
Thereafter, the reaction product was transferred to a polymerization reactor, heated to 290 ° C., and subjected to a polycondensation reaction under a high vacuum of 0.2 mmHg or less to obtain a polyester chip having an intrinsic viscosity of 0.60.

100 parts by weight of this polyester chip and 3,5-
0.047 parts by weight of tetrabutylphosphonium dicarboxybenzenesulfonate are mixed before being fed to a single screw extruder, and this mixture is fed to a single screw extruder to have a thickness of 210 ° C at 210 ° C.
It was melt-extruded into a film having a thickness of μm, and was tightly adhered to the mirror-surfaced cooling drum surface by an electrostatic casting method using a linear electrode. At this time, the speed of the cooling drum was gradually increased, and the maximum casting speed at which the cooling film could be manufactured stably without causing a pin-like defect of the film due to the cause of poor adhesion was 97 m / min. Of this polyester film
Value of AC volume resistivity at 285 ° C (melting point + 30 ° C) (F / D
Value) is 6.4 × 10 ⁶ Ω · cm, and the value of DC volume resistivity (F /
A value) was 4.1 × 10 ⁸ Ω · cm.

Subsequently, a cooling film (unstretched film)
Biaxially stretched 3.6 times in the vertical direction and 3.9 times in the horizontal direction.
The film was heat-set at 230 ° C to produce a biaxially stretched film.
The film was examined for foreign matter and found to have an area of 1 cm ²
Among them, 7 pieces with a size of 5 to 10 μm and one piece with a size of 10 to 20 μm showed no foreign substances of 20 μm or more. These results are shown in Tables 1 and 2.

Examples 2 to 5 In Example 1, calcium carbonate having an average particle size of 0.6 μm was used in place of the spherical silica, and the amount of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate added was as shown in Table 1. The casting was carried out in the same manner as in Example 1 except that the amount was changed to the amount shown in Table 1 and the film thickness at the time of casting was changed to 150 μm. The results are shown in Tables 1 and 2.

[Comparative Examples 1 to 4] In Example 1, after adding 0.2 parts of spherical silica, sodium acetate trihydrate or potassium acetate trihydrate was added in the amounts shown in Table 1 and the uniaxial extrusion was performed. Before feeding to the machine, polyester chips and 3,
Casting was carried out in the same manner as in Example 1, except that tetrabutylphosphonium 5-dicarboxybenzenesulfonate was not mixed. The results are shown in Tables 1 and 2.

Comparative Example 5 The procedure of Example 1 was repeated, except that tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate was added in an amount of 0.52 parts by weight. Was produced.

As a result of evaluating the foreign matter in the film, the area 1c
one more than the size 40μm in m ^2, 3 or those 20Myuemu～40myuemu, admitted 23 black foreign matter that of 10 m to 20 m. As a result of analyzing the composition of the black foreign matter, antimony or antimony and phosphorus were detected as main components.

The film was of no commercial value as a base film for optical applications and high density magnetic recording materials.

Example 6 The average particle size in Example 1
A 15-μm thick biaxially stretched film was produced in the same manner as in Example 1 except that 0.2 parts of 0.6 μm spherical silica was not added.

As a result of evaluating the foreign matter in the film, the area 1c
foreign matter sizes 5μm~10μm average in m ² at 6, 10 [mu]
m or more, and a high-quality film with very few foreign matters was obtained. The results are shown in Tables 1 and 2.

[Comparative Example 6] In Example 1, the average particle size was
Not adding 0.2 parts of 0.6 μm spherical silica, and when the reaction temperature reached 220 ° C. during the transesterification reaction, 0.031 parts by weight of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate and 0.124 parts by weight of ethylene glycol A biaxially stretched film having a thickness of 15 μm was produced in the same manner as in Example 1, except that the mixture of (1) and (2) was added as a solution heated to 40 ° C.

As a result of evaluating the foreign matter in the film, the area 1c
foreign matter sizes 5μm~10μm average in m ² at 50, 10 [mu]
The average number of foreign substances of m or more was 2 and the number of foreign substances was larger than that of Example-6, and the application was limited to a film that was not suitable for a base film of a high-density magnetic recording material. The results are shown in Tables 1 and 2.

Example 7 0.018 parts of manganese acetate tetrahydrate was added to a mixture of 100 parts of dimethyl 2,6-naphthalenedicarboxylate and 50 parts of ethyne glycol, and the mixture was gradually heated from 150 ° C. to 240 ° C. A transesterification reaction was performed. After the transesterification reaction, 0.013 parts of trimethyl phosphate and 0.2 parts of true spherical silica having an average particle diameter of 0.6 μm were added.After 5 minutes, 0.008 parts by weight of titanium acetate was added, and the reaction product was heated to 290 ° C. A polycondensation reaction was performed under a high vacuum of 0.2 mmHg or less to produce a polyester having an intrinsic viscosity of 0.58.

The polyester chip was mixed with tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate.
039 parts by weight are mixed before being supplied to the single-screw extruder, and this mixture is supplied to the single-screw extruder to produce a biaxially stretched film in the same manner as in Example 1 except that the melt extrusion temperature is set to 305 ° C. did. The results are shown in Tables 1 and 2.

[Example 8] In Example 1, 100 parts of dimethyl terephthalate was changed to 88 parts of dimethyl terephthalate and 12 parts of dimethyl isophthalate, and tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate was added. The procedure was as in Example 1, except that the amount was changed from 0.047 parts by weight to 0.026 parts by weight. The results are shown in Tables 1 and 2.

Example 9 The procedure of Example 4 was repeated, except that 0.0015 part of potassium acetate trihydrate was additionally added after the addition of antimony trioxide. The results are shown in Tables 1 and 2.

Example 10 Tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate of Example 1 0.04
Using a polyester chip mixed with 7 parts by weight, it was melt-extruded into a 210 μm thick film and adhered to the surface of a cooling drum having a large number of channel bar cracks having a groove width of 3 μm by an electrostatic adhesion method.

Example 11 Tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate of Example 1 0.00
Using a polyester chip mixed with 13 parts by weight, it was melt-extruded into a 55 μm-thick film and adhered to the surface of a cooling drum having an approximately 2 μm-thick water coating film together with an electrostatic adhesion method.

Example 12 A mixture of 50% by weight of polyethylene terephthalate (lubricant content) in a chip shape having a particle size of 4 mm and 50% by weight of flaked polyethylene terephthalate (lubricant content) having an average particle size of about 3 mm was added to 3,8%. 5-Dicarboxybenzenesulfonic acid tetrabutylphosphonium salt 0.05
2 wt% were mixed and melt-mixed while being vacuum-vented with a twin-screw extruder, extruded into a film having a thickness of 150 μm, and solidified on a cooling drum by an electrostatic adhesion method. The results are shown in Tables 1 and 2.

Comparative Examples 7 and 8 In Example 2, 3,5-
Example 2 except that sodium 3,5-dicarboxybenzenesulfonate was added in the amount shown in Table 1 in place of tetrabutylphosphonium dicarboxybenzenesulfonate.
Casting in the same way as The results are shown in Tables 1 and 2.

Example 13 Manganese acetate · 4 was added to a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol.
0.038 parts of water salt was added, and transesterification was carried out while gradually raising the temperature from 150 ° C to 240 ° C. After the transesterification was completed, 0.025 part of trimethyl phosphate was added, and the mixture was reacted for 15 minutes. Then, 0.045 part of antimony trioxide was added, and the mixture was further reacted for 5 minutes. Thereafter, the reaction product was transferred to a polymerization reactor, heated to 290 ° C., and subjected to a polycondensation reaction under a high vacuum of 0.2 mmHg or less to obtain a polyester (A) having an intrinsic viscosity of 0.60.

After completion of the transesterification reaction, after adding predetermined amounts of trimethyl phosphate and antimony trioxide, 10
Minutes after the addition of 0.030 parts of sodium acetate trihydrate, the same procedure as for polyester (A) was repeated except that the intrinsic viscosity was 0.3.
A polyester (B) of 60 was obtained.

Further, after the transesterification reaction was completed, predetermined amounts of trimethyl phosphate and antimony trioxide were added, and then 10
After reacting for 1 minute, calcium carbonate with an average particle size of 1.0 μm
A polyester (C) having an intrinsic viscosity of 0.60 was obtained in exactly the same manner as the polyester (A) except that 1.0 part was mixed with 5 parts of ethylene glycol and added.

The polyester (A) thus obtained,
(B), (C) and 0.031 part of 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt are mixed before feeding to a single screw extruder, and the mixed polyester (D)
The amounts of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate and sodium acetate trihydrate are shown in Table 1, and the content of calcium carbonate having an average particle size of 1.0 μm is 0.10 parts by weight per 100 parts by weight of the polymer. It was adjusted to be.

The polyester (D) was heated at 290 ° C. to a thickness of 210
After being melt-extruded into a film having a thickness of μm and cooled on a cooling drum surface by an electrostatic casting method, the film was stretched 3.6 times in a longitudinal direction and 3.9 times in a transverse direction to obtain a biaxially stretched film having a thickness of 15 μm. The results are shown in Tables 1 and 2.

[0142]

[Table 1]

[0143]

[Table 2]

[0144]

According to the present invention, by producing an aromatic polyester film by the method shown in the present invention, a molten film of an aromatic polyester can be cooled by bringing it into close contact with a rotary cooling drum. A film having a uniform thickness without surface defects under productivity can be obtained.

[Brief description of the drawings]

FIG. 1 shows an apparatus for measuring the volume resistivity of a film.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme Court II (Reference) B29K 67:00 B29L 7:00 (72) Inventor Noriyuki Baba 13-1 Kiyohara Industrial Park Utsunomiya City, Tochigi Prefecture Teijin Limited F-term in Utsunomiya office (reference) 4F071 AA44X AA45 AA46 AA47 AA47X AB14 AB18 AB21 AB23 AB24 AB25 AC09 AC14 AC15 AE15 AF37Y AF58 AG13 AH04 AH12 AH14 AH19 BB06 BB08 BC01 4F207 AA24 AA27 63 DD057 DD067 DE057 DE067 DE077 DE087 DE227 DE237 DG047 DG057 DH047 EG027 EG037 EG077 EG107 EW176 GG00 GP00 GQ01 GS01 4J029 AA03 AB05 AC02 AE03 BA03 BH02 BH03 BH07 B03H03 CH03 HA03 CH03 HA03 JA123 JA183 JA203 JA263 JB173 JC372 JC373 JC632 JC633 JF023 JF033 JF043 JF053 JF123 JF133 JF143 JF153 JF163 KH01

Claims (19)

[Claims] 1. A method for producing an aromatic polyester film by extruding a molten film of a thermoplastic aromatic polyester onto a rotary cooling drum, and then closely contacting the film on the rotary cooling drum and cooling the film. 0.1 to 45 m for the bifunctional carboxylic acid component as an aromatic polyester
A sulfonic acid quaternary phosphonium salt having a mol% ester-forming functional group is added to the aromatic polyester after the polymerization reaction, and the value of the AC volume resistivity of the molten film is 6.5.
Using an aromatic polyester of × 10 ⁸ Ωcm or less, and applying a charge to the molten surface of the aromatic polyester in a non-contact manner in the vicinity of the location where the molten film reaches the rotating cooling drum. A method for producing an aromatic polyester film, comprising: 2. The method for producing an aromatic polyester film according to claim 1, wherein the rotational peripheral speed of the rotary cooling drum is at least 50 m / min. 3. The rotating peripheral speed of the rotating cooling drum is 60 to 200 m.
The method for producing an aromatic polyester film according to claim 2, wherein the ratio is / min. 4. The method for producing an aromatic polyester film according to claim 1, wherein the rotary cooling drum has a large number of channel-like microcracks on the surface. 5. The rotating peripheral speed of the rotary cooling drum is 80 to 200 m.
The method for producing an aromatic polyester film according to claim 4, wherein the ratio is / min. 6. The method for producing an aromatic polyester film according to claim 1, wherein the rotary cooling drum has a mirror surface. 7. The rotating peripheral speed of the rotary cooling drum is 60 to 150 m.
The method for producing an aromatic polyester film according to claim 6, wherein the ratio is / min. 8. The method for producing an aromatic polyester film according to claim 1, wherein a liquid coating containing water as a main component is provided on the rotating surface of the rotary cooling drum. 9. A quaternary phosphonium salt of sulfonic acid having an ester-forming functional group is represented by the following formula: (Where A is an n + 2 valent aliphatic group or aromatic group having 2 to 18 carbon atoms, X ₁ and X ₂ are the same or different and are a hydrogen atom or an ester-forming functional group, and n is 1 or R ₁ , R ₂ , R ₃ and R ₄ are the same or different and are an alkyl group having 1 to 18 carbon atoms, a benzyl group or an aryl group having 6 to 12 carbon atoms.
X ₁ and X ₂ are not simultaneously hydrogen. The method for producing an aromatic polyester film according to claim 1, wherein 10. A method for producing an aromatic polyester film by extruding a molten film of a thermoplastic aromatic polyester onto a rotary cooling drum, and then bringing the film into close contact with the rotary cooling drum and cooling the film. As the aromatic polyester, 0.1 to 4 based on the difunctional carboxylic acid component
A sulfonic acid quaternary phosphonium salt having an ester-forming functional group of 5 mmol% is added to the aromatic polyester after the polymerization reaction, and 0.1 to 20 mmol% based on the bifunctional carboxylic acid component.
Contains an alkali metal or alkaline earth metal compound, and the value of the AC volume resistivity of the molten film is 6.4 × 1
Using the 0 ⁸ Ω · cm or less of the aromatic polyester, and in the vicinity of the melt film of the aromatic polyester reaches onto a rotating cooling drum, characterized in applying a non-contact electric charge to the molten surface of the film A method for producing an aromatic polyester film. 11. The method for producing an aromatic polyester film according to claim 10, wherein the rotational peripheral speed of the rotary cooling drum is at least 60 m / min. 12. The rotating peripheral speed of the rotating cooling drum is 60 to 20.
The method for producing an aromatic polyester film according to claim 11, wherein the flow rate is 0 m / min. 13. An aromatic polyester comprising 0.5 × 10 ^{6 to} 2.0
The method for producing an aromatic polyester film according to claim 10, which shows a value of an AC volume resistivity of the molten film of × 10 ⁷ Ω · cm. 14. The method for producing an aromatic polyester film according to claim 1, wherein the proportion of the quaternary phosphonium salt of a sulfonic acid having an ester-forming functional group and the polyester is 10 to 99.9%. 15. A film of a thermoplastic aromatic polyester, wherein the aromatic polyester is (1) a difunctional carboxylic acid component constituting the aromatic polyester.
A sulfonic acid quaternary phosphonium salt having an ester-forming functional group in a proportion of 0.1 to 45 mmol% is added to and contained in the aromatic polyester after the polymerization reaction, and (2)
In the relationship between the AC volume resistivity and the DC volume resistivity of the film in the molten state, the same DC volume resistivity is higher than that of the aromatic polyester containing a sodium sulfonate having an ester-forming functional group in a polymer chain. , An aromatic polyester film having a smaller value of AC volume resistivity. 16. The aromatic polyester film according to claim 14, wherein the aromatic polyester is a polyester containing ethylene terephthalate as a main component. 17. The aromatic polyester is ethylene 2,6.
The aromatic polyester film according to claim 14, which is a polyester containing naphthalate as a main component. 18. A quaternary phosphonium sulfonic acid salt having an ester-forming functional group is represented by the following formula: (Where A is an n + 2 valent aliphatic group or aromatic group having 2 to 18 carbon atoms, X ₁ and X ₂ are the same or different and are a hydrogen atom or an ester-forming functional group, and n is 1 or R ₁ , R ₂ , R ₃ and R ₄ are the same or different and are an alkyl group having 1 to 18 carbon atoms, a benzyl group or an aryl group having 6 to 12 carbon atoms.
X ₁ and X ₂ are not simultaneously hydrogen. The aromatic polyester film according to claim 14, which is represented by the formula: 19. A film of a thermoplastic aromatic polyester, wherein said aromatic polyester has an ester formation ratio of 0.1 to 45 mmol% based on (1) a bifunctional carboxylic acid component constituting the aromatic polyester. A sulfonic acid quaternary phosphonium salt having a functional group is added to and contained in the aromatic polyester after the completion of the polymerization reaction, and (2) 0.1 to 20 mmol% based on the bifunctional carboxylic acid component constituting the aromatic polyester. And (3) a sulfonic acid having an ester-forming functional group in the relationship between the AC volume resistivity and the DC volume resistivity of the film in a molten state. At the same value of DC volume resistivity than the aromatic polyester containing a sodium salt in the polymer chain,
An aromatic polyester film exhibiting a smaller value of AC volume resistivity.