JP2005097579A - Polyester composition and film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition having less increase of filtering pressure at the time of production of a polyester film, good film formability, less foreign matters than those of conventional polyester compositions, small melt resistivity, and excellent productivity and a film therefrom. <P>SOLUTION: The polyester composition contains a titanium compound having a specific functional group as a substituent between 0.5 and 30 ppm in terms of a titanium atom weight based on the polyester, contains an alkaline earth metal compound between 0 and 80 ppm in terms of an alkaline earth metal atom weight, and contains as phosphorus compounds, phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphine oxide, phosphonous acid, phosphinous acid, phosphine, phosphate, phosphite, phosphonate, and phosphinate, wherein, when Ma (mol/g) represents the content of alkali metal elements, Md (mol/g) represents the content of alkaline earth metal elements, and Mp represents the content of phosphorus elements, Ma, Md, and Mp satisfy the formula: Ma+2×Md+1≥Mp×3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a polyester composition and a film that have a low filtration pressure increase during production of a polyester film, good film-forming properties, less foreign matter than conventional products, low melt specific resistance, and excellent productivity. About.

  Polyester is used for various purposes because of its high functionality, and is used for clothing, materials, and medical use, for example. Among them, polyethylene terephthalate is excellent in terms of versatility and practicality and is preferably used.

  In general, polyethylene terephthalate is produced from terephthalic acid or an ester-forming derivative thereof and ethylene glycol. In a commercial process for producing a high molecular weight polymer, an antimony compound is widely used as a polycondensation catalyst. However, polymers containing antimony compounds have some undesirable properties as described below.

  For example, when a polymer obtained using an antimony catalyst is melt-spun into a fiber, it is known that an antimony catalyst residue is deposited around the die hole. As this deposition progresses, it becomes a cause of defects in the filament, so that it needs to be removed in a timely manner. The deposition of the antimony catalyst residue is considered to be due to the fact that the antimony compound in the polymer is denatured in the vicinity of the die and a part thereof is vaporized and dissipated, and then a component mainly composed of antimony remains in the die. In addition, when an antimony compound is used as a polycondensation catalyst in the production of polyester such as polyethylene terephthalate, if polyester is formed continuously over a long period of time, foreign matter adheres to and deposits around the die, and the May occur or may precipitate on the surface of the film and cause surface defects.

  In addition, the antimony catalyst residue in the polymer tends to become relatively large particles, and it becomes a foreign matter, causing an increase in the filtration pressure of the filter during molding, causing yarn breakage during spinning or film tearing during film formation, etc. It has undesirable characteristics and contributes to a decrease in operability.

  In view of the above background, there is a demand for polyesters that contain little or no antimony. Thus, when the role of the polycondensation catalyst is required for compounds other than antimony compounds, germanium compounds are known as catalysts, but germanium compounds are very expensive and difficult to use for general purposes.

  Furthermore, it has been proposed to use a titanium compound such as titanium tetrabutoxide as a polycondensation catalyst other than the antimony compound. However, when such a titanium compound is used, there are problems such as the above-mentioned base streaks and film surface defects. However, there is a problem that the obtained polyester itself is colored yellow, the heat stability of the melt becomes unstable, the film is torn, and the productivity is deteriorated.

On the other hand, the proposal which uses the titanium complex which consists of a titanium compound and a phosphorus compound as a polymerization catalyst as a catalyst for polyester polymerization is made (refer patent documents 1-3). Although this method can reduce foreign matters caused by the catalyst, it is not sufficient, and the color tone of the resulting polymer is not sufficient, and furthermore, when it is used as a film with a large melting specific resistance, the productivity is low. There was a problem. Therefore, further improvement is also demanded for titanium compounds.
JP 2001-524536 A Japanese translation of PCT publication No. 2002-512267 JP 2002-293909 A

  The object of the present invention is to solve the above-mentioned problems of the prior art, with little increase in filtration pressure during the production of a polyester film, good film-forming properties, less foreign matter than conventional products, and a melt specific resistance. An object of the present invention is to provide a polyester composition and a film which are small and excellent in productivity.

  In order to achieve the above object, the present invention provides a titanium compound having at least one selected from the group consisting of the functional groups represented by formulas (1) to (6) as a substituent in terms of a titanium atomic weight based on polyester. 0.5-30 ppm, alkaline earth metal compound in an alkaline earth metal atomic weight of 0-80 ppm, phosphorous acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphine oxide, phosphonous acid, Contains at least one compound selected from the group consisting of phosphinic acid, phosphine, phosphate, phosphite, phosphonate and phosphinate, and the content of alkali metal element is Ma (mol / g), alkaline earth metal element When the content of Md is Md (mol / g) and the content of phosphorus element is Mp, Ma, Md and M There characterized polyester composition satisfies the following equation.

    Ma + 2 × Md + 1 ≧ Mp × 3

(However, in Formula (1)-Formula (5), R < ¹ > -R < ³ > is each independently any group shown below. Hydrogen C1-C30 organic group)

  As will be described below, the polyester resin composition and film of the present invention have few surface foreign matters, have good color tone and excellent productivity, and can be suitably used as a magnetic recording medium.

  As the polyester used in the present invention, a polymer synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof can be used. Especially, what can be used as molded articles, such as a fiber, a film, a bottle, is preferable.

  Specific examples of such polyester include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polyethylene-1,2- And bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. In the present invention, the most commonly used polyethylene terephthalate or a polyester copolymer mainly containing ethylene terephthalate units is suitable.

  In addition to diethylene glycol, these polyesters include dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, and cyclohexanedicarboxylic acid, and esters thereof. Formable derivatives, dioxy compounds such as polyethylene glycol, hexamethylene glycol, neopentyl glycol, polypropylene glycol and cyclohexanedimethanol, oxycarboxylic acids such as p- (β-oxyethoxy) benzoic acid and ester-forming derivatives thereof It may be polymerized.

  In the polyester used in the present invention, the titanium compound as a polymerization catalyst is a titanium compound whose substituent is at least one selected from the group consisting of functional groups represented by the following formulas (1) to (6): Examples thereof include titanium oxide.

(However, in Formula (1)-Formula (5), R < ¹ > -R < ³ > is each independently any group shown below. Hydrogen C1-C30 organic group)
In addition, as said C1-C30 organic group, at least 1 sort (s) chosen from the group which consists of an alkyl group, an alkoxy group, a hydroxyl group, a carbonyl group, an acetyl group, a carboxyl group, an ester group, and an amino group in the structure It is preferable that the functional group is included.

  As a preferred embodiment, titanium diisopropoxybisacetylacetonate or titanium triethanolaminate isopropoxy containing two or more of the substituents represented by the formulas (1) to (6) as a titanium compound. There are

Incidentally, a functional group which the titanium compound is represented by the formula (1) to (3) as a substituent, is R ¹ to R ³ in Formula (1) to (3) each independently represent a hydrogen or carbon It is preferable that the organic group has a number of 1 to 30 because the substituent becomes steric hindrance, restrains the PET main chain and suppresses thermal decomposition.

In addition, at least one substituent of R ^{1 to} R ³ in Formula (1) to Formula (3) is hydrogen or a hydroxyl group, or an alkyl group, an alkoxy group, a hydroxyl group, a carbonyl group, or an acetyl group. When the organic group has 1 to 30 carbon atoms and contains at least one functional group selected from the group consisting of a carboxyl group, an ester group and an amino group, the substituent becomes a steric hindrance and the PET main chain is However, it is more preferable that the functional group is a polar group such as a hydroxyl group, a carbonyl group, an acetyl group, or a carboxyl group, since it has a good affinity with the carbonyl group of PET and can exhibit a strong steric hindrance effect. Such substituents include functional groups such as lactic acid, citric acid, acetylacetone and salicylic acid.

Further, the titanium compound has a functional group represented by the formula (1) as a substituent, and at least one substituent of R ^{1 to} R ³ in the formula (1) is hydrogen, or an alkyl group, carboxyl When the organic group has 1 to 30 carbon atoms and has at least one functional group selected from the group consisting of a group and an ester group, the bond between titanium and the ligand becomes stronger, and the above effects are enhanced and heat resistance is improved. Becomes better. Such compounds include lactic acid and citric acid.

Also, a functional group which the titanium compound is represented by formula (4) as a substituent, when R ¹ in formula (4) is an organic group having 1 to 30 carbon atoms, preferable in terms of heat resistance. In this case, the organic group having 1 to 30 carbon atoms includes at least one selected from the group consisting of an alkyl group, an alkoxy group, a hydroxyl group, a carbonyl group, an acetyl group, a carboxyl group, an ester group, and an amino group in the structure. It preferably contains a functional group.

  Examples of the above formula (1) include, for example, alkoxy groups such as ethoxide, propoxide, isopropoxide, butoxide, 2-ethylhexoxide, and hydroxy polyvalent carboxylic acid compounds such as lactic acid, malic acid, tartaric acid, and citric acid. The functional group which consists of is mentioned.

  Moreover, as a formula (2), the functional group which consists of ketoester type compounds, such as (beta) -diketone type compounds, such as acetylacetone, methyl acetoacetate, and ethyl acetoacetate, is mentioned.

  Moreover, as a formula (3), the functional group which consists of phenoxy, a cresylate, salicylic acid, etc. is mentioned.

  Formula (4) includes acylate groups such as lactate and stearate, phthalic acid, trimellitic acid, trimesic acid, hemimellitic acid, pyromellitic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid , Polycarboxylic acid compounds such as sebacic acid, maleic acid, fumaric acid, cyclohexanedicarboxylic acid or their anhydrides, ethylenediaminetetraacetic acid, nitrilotripropionic acid, carboxyiminodiacetic acid, carboxymethyliminodipropionic acid, diethylenetriamino Examples include functional groups composed of nitrogen-containing polyvalent carboxylic acids such as pentaacetic acid, triethylenetetraminohexaacetic acid, iminodiacetic acid, iminodipropionic acid, hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, and methoxyethyliminodiacetic acid. It is done.

  Moreover, as a formula (5), the functional group which consists of aniline, a phenylamine, diphenylamine etc. is mentioned.

  Among these, the formula (1) and / or the formula (4) are preferably included from the viewpoint of the thermal stability and color tone of the polymer.

  Examples of the titanium compound include titanium diisopropoxybisacetylacetonate and titanium triethanolamate isopropoxide containing two or more of the substituents of the formulas (1) to (6).

In the present invention, the catalyst means all or part of the following reactions (1) to (3) in a polymer synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof: Refers to a compound that substantially contributes to the promotion of the reaction.
(1) Esterification reaction which is reaction of dicarboxylic acid component and diol component (2) Transesterification reaction which is reaction of ester-forming derivative component of dicarboxylic acid and diol component (3) Substantially ester reaction or transesterification Polycondensation reaction in which the reaction is completed and the resulting polyethylene terephthalate low polymer is increased in degree of polymerization by dediol reaction. Titanium oxide may be used as the titanium compound. Examples of the titanium oxide include composite oxides in which the main metal elements are titanium and silicon, and ultrafine titanium oxide.

  There are no particular limitations on the method for producing the composite oxide comprising the main metal element titanium and silicon and the ultrafine particle titanium oxide. For example, in the method for producing the product by hydrolysis reaction using an alkoxide compound of titanium as a raw material, Obtained by controlling the speed. Specifically, for example, a titanium alkoxide compound as a main raw material is allowed to coexist with a small amount of another metal alkoxide compound such as silicon or zirconium or a polyhydric alcohol compound, and both coprecipitation method, partial hydrolysis method, distribution It can be synthesized by a coordinate chemical sol-gel method or the like. Here, the coprecipitation method is a method in which a solution having a predetermined composition containing two or more components is prepared, and the hydrolysis reaction proceeds with the composition. The partial hydrolysis method is a method in which one component is preliminarily hydrolyzed, and the other component is added thereto to further proceed hydrolysis. The coordination chemical sol-gel method is a method in which a polyhydric alcohol compound having a plurality of functional groups in the molecule is coexisted together with a titanium alkoxide raw material, and a reaction product is formed between the two in advance, thereby allowing subsequent hydrolysis. It is intended to control the rate of reaction. For example, Ueno et al., “Catalyst Preparation Using Metal Alkoxide”, page 321 line 1 to page 353 line 16 (IPC, issued on August 10, 1993). Etc. are described. The ultrafine titanium oxide used as the catalyst has a molecular weight of less than 100,000 (g / mol), which is preferable in terms of catalyst activity and foreign matter suppression. The molecular weight of the ultrafine titanium oxide is more preferably 500 to 100,000 (g / mol), still more preferably 1,000 to 50,000 (g / mol), and particularly preferably 1,500 to 20,000 (g / mol). mol).

  When the titanium compound as a polycondensation catalyst in the present invention is contained in an amount of 0.5 to 30 ppm as a titanium atom weight with respect to the obtained polymer weight (polyester composition), the polymerization activity is high. Heat resistance is also good, which is preferable. If the amount exceeds 30 ppm, the heat resistance is deteriorated, and further causes a foreign matter due to the catalyst. As content, More preferably, it is 1-25 ppm, More preferably, it is 1-20 ppm. In order to contain a predetermined amount of these titanium compounds in the polymer, a predetermined amount may be added when the compounds are added (the added amount is maintained in the polymer as it is).

  The polyester composition of the present invention contains 0 to 80 ppm of the alkaline earth metal compound as the total amount of the alkaline earth metal atomic weight relative to the polyester. This can be achieved, for example, by adding an alkaline earth metal compound at 0 to 80 ppm in terms of the total weight of the alkaline earth metal compound atom to the polyester at any time during the production of the polyester, thereby reducing the melt specific resistance and producing Can be improved. This content is preferably 1 to 60 ppm because productivity is particularly good and heat resistance can be maintained.

  Although it does not specifically limit as an alkaline-earth metal compound, Specifically, a magnesium acetate, a calcium acetate, magnesium hydroxide, calcium hydroxide etc. can be used, for example. A magnesium compound is particularly preferable. The magnesium compound used in this case is not particularly limited, but specifically, magnesium chloride, magnesium bromide, magnesium nitrate, magnesium carbonate, magnesium acetylacetonate, magnesium acetate, magnesium acetate tetrahydrate, magnesium acetate dihydrate Examples include salts.

  In addition, it is good to add the phosphorus contained in the polyester of this invention as a phosphorus compound in the manufacturing process of polyester. As such a phosphorus compound, at least one selected from the group consisting of phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphine oxide, phosphonous acid, phosphinic acid, phosphine, phosphate, phosphite, phosphonate and phosphinate It is preferable that it is a compound of these. Specifically, for example, phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate and the like phosphoric acid series, phosphorous acid, trimethyl phosphite, triethyl phosphite, triphenyl phosphite and the like. Phosphate, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthryl Phosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic acid, 2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxy Phenylphosphonic acid, 2,6-dicarboxyl Nylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,3,4-tricarboxyphenylphosphonic acid, 2,3,5-tricarboxyphenylphosphonic acid, 2,3 , 6-tricarboxyphenylphosphonic acid, 2,4,5-tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, methylphosphonic acid dimethyl ester, methylphosphonic acid diethyl ester, ethylphosphonic acid dimethyl ester, ethyl Phosphonic acid diethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, benzylphosphonic acid dimethyl ester, benzylphosphonic acid diethyl ester, benzylphosphonic acid diester Phenyl ester, lithium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), sodium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), magnesium bis (3 Ethyl 5-di-tert-butyl-4-hydroxybenzylphosphonate), calcium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate), diethylphosphonoacetic acid, methyl diethylphosphonoacetate, Phosphonic acid compounds such as ethyl diethylphosphonoacetate, hypophosphorous acid, sodium hypophosphite, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, tolylphosphinic acid Xylylphosphinic acid, Biphenylylphosphinic acid, diphenylphosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, ditolylphosphinic acid, dixylphosphinic acid, dibiphenylylphosphinic acid, naphthylphosphinic acid, Anthrylphosphinic acid, 2-carboxyphenylphosphinic acid, 3-carboxyphenylphosphinic acid, 4-carboxyphenylphosphinic acid, 2,3-dicarboxyphenylphosphinic acid, 2,4-dicarboxyphenylphosphinic acid, 2,5- Dicarboxyphenylphosphinic acid, 2,6-dicarboxyphenylphosphinic acid, 3,4-dicarboxyphenylphosphinic acid, 3,5-dicarboxyphenylphosphinic acid, 2,3,4-trica Boxyphenylphosphinic acid, 2,3,5-tricarboxyphenylphosphinic acid, 2,3,6-tricarboxyphenylphosphinic acid, 2,4,5-tricarboxyphenylphosphinic acid, 2,4,6-tricarboxy Phenylphosphinic acid, bis (2-carboxyphenyl) phosphinic acid, bis (3-carboxyphenyl) phosphinic acid, bis (4-carboxyphenyl) phosphinic acid, bis (2,3-dicarboxylphenyl) phosphinic acid, bis ( 2,4-dicarboxyphenyl) phosphinic acid, bis (2,5-dicarboxyphenyl) phosphinic acid, bis (2,6-dicarboxyphenyl) phosphinic acid, bis (3,4-dicarboxyphenyl) phosphinic acid, Bis (3,5-dicarboxyphenyl) phosphinic acid, bis (2,3 4-tricarboxyphenyl) phosphinic acid, bis (2,3,5-tricarboxyphenyl) phosphinic acid, bis (2,3,6-tricarboxyphenyl) phosphinic acid, bis (2,4,5-tricarboxyphenyl) ) Phosphinic acid and bis (2,4,6-tricarboxyphenyl) phosphinic acid, methylphosphinic acid methyl ester, dimethylphosphinic acid methyl ester, methylphosphinic acid ethyl ester, dimethylphosphinic acid ethyl ester, ethylphosphinic acid methyl ester, Diethylphosphinic acid methyl ester, ethylphosphinic acid ethyl ester, diethylphosphinic acid ethyl ester, phenylphosphinic acid methyl ester, phenylphosphinic acid ethyl ester, phenylphosphinic acid phenyl ester, diphenyl Nylphosphinic acid methyl ester, diphenylphosphinic acid ethyl ester, diphenylphosphinic acid phenyl ester, benzylphosphinic acid methyl ester, benzylphosphinic acid ethyl ester, benzylphosphinic acid phenyl ester, bisbenzylphosphinic acid methyl ester, bisbenzylphosphinic acid ethyl ester, Phosphinic acids such as bisbenzylphosphinic acid phenyl ester, trimethylphosphine oxide, triethylphosphine oxide, tripropylphosphine oxide, triisopropylphosphine oxide, tributylphosphine oxide, phosphine oxides such as triphenylphosphine oxide, methylphosphonous acid, ethyl Phosphonous acid, propylphosphonous acid, isopropyl phosphite Phosphonic acid series such as phonic acid, butylphosphonous acid, phenylphosphonous acid, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, dimethyl Phosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, diphenylphosphinic acid and other phosphinic acid systems, methylphosphine, dimethylphosphine, trimethylphosphine, ethylphosphine, diethylphosphine, Examples include phosphines such as triethylphosphine, phenylphosphine, diphenylphosphine, and triphenylphosphine, and any one or two of these are preferable. In particular, from the viewpoints of thermal stability and color tone improvement, phosphoric acid and / or phosphonic acid are preferable.

  The polyester used in the present invention preferably contains no antimony compound or 30 ppm or less in terms of antimony atoms relative to the polyester. By setting it within this range, it is possible to obtain a polymer that is less likely to cause contamination of the die during molding and is relatively inexpensive. More preferably, it is preferably 10 ppm or less, and particularly not substantially contained.

  In the polyester composition of the present invention, when the content of alkali metal element is Ma (mol / g), the content of alkaline earth metal element is Md (mol / g), and the content of phosphorus element is Mp, Ma , Md and Mp satisfy the following formula.

Ma + 2 × Md + 1 ≧ Mp × 3
In the polyester composition of the present invention, the detailed reason for the polyester composition satisfying this formula is unknown, but the heat resistance is particularly good, there are few foreign matters containing titanium element, the color tone is good, and the Good film properties.

  More preferably, the following expression is satisfied.

Ma + 2 × Md ≧ Mp × 3
A polyester composition satisfying this formula is particularly excellent in terms of foreign matter, color tone, and heat resistance, and has good film forming properties.

  Further, when the molar ratio of Ti / P is 0.1 to 20 as phosphorus atoms with respect to the titanium atoms of the titanium compound, the thermal stability and color tone of the polyester are favorable, which is preferable. More preferably, it is Ti / P = 0.2-10, More preferably, Ti / P = 0.3-5.

  The titanium compound and phosphorus compound used in the present invention may be added to the polyester reaction system as they are, but are mixed in advance with a solvent containing a diol component that forms a polyester such as ethylene glycol or propylene glycol to form a solution or slurry. If necessary, it is preferable to remove low-boiling components such as alcohol used in the synthesis of the titanium compound or phosphorus compound and then add to the reaction system, since foreign matter formation in the polymer is further suppressed. The addition time includes an esterification reaction catalyst and a transesterification reaction catalyst, a method of adding the catalyst immediately after the addition of the raw material, and a method of adding it together with the raw material. Further, when added as a polycondensation reaction catalyst, it may be substantially before the start of the polycondensation reaction, before the esterification reaction or transesterification reaction, or after completion of the reaction, before the polycondensation reaction catalyst is started. It may be added. In this case, in order to suppress the deactivation of the catalyst due to the contact between the titanium compound and the phosphorus compound, a method of adding to a different reaction tank, or the addition interval of the titanium compound and the phosphorus compound in the same reaction tank is 1 to 15 minutes. And a method of separating the addition position.

  In the present invention, a titanium compound previously reacted with a phosphorus compound can also be used as a catalyst. In this case, (1) a titanium compound is mixed with a solvent, a part or all of the titanium compound is dissolved in the solvent, and the phosphorus compound is dissolved and diluted in the stock solution or the solvent and added dropwise to the mixed solution. (2) In the case of using a ligand of a titanium compound such as a hydroxycarboxylic acid compound or a polyvalent carboxylic acid compound, the titanium compound or the ligand compound is mixed in a solvent, and a part or all thereof is mixed in the solvent. Dissolve, and dissolve and dilute the ligand compound or titanium compound in the stock solution or solvent in this mixed solution. Moreover, it is preferable from the viewpoint of thermal stability and color tone improvement that a phosphorus compound is further dissolved and diluted in a stock solution or a solvent and added dropwise to the mixed solution. Said reaction conditions are performed by heating at the temperature of 0-200 degreeC for 1 minute or more, Preferably it is 2-100 minutes at the temperature of 20-100 degreeC. The reaction pressure at this time is not particularly limited, and may be normal pressure. The solvent used here can be selected from those capable of dissolving a part or all of the titanium compound, phosphorus compound and carbonyl group-containing compound, preferably water, methanol, ethanol, ethylene glycol, propane. It is selected from diol, butanediol, benzene and xylene.

When the polyester composition of the present invention is used as a film, the volume specific resistance value of the polyester composition is preferably 1 × 10 ⁶ Ω · cm to 1 × 10 ⁹ Ω · cm, particularly preferably 1 × 10 ^7. Ω · cm to 5 × 10 ⁸ Ω · cm. By satisfying this range, the antistatic application castability is improved, the adhesion between the film and the casting drum is good at the time of melt extrusion casting, and it is difficult for air to enter, and the film forming speed can be increased.

  Regarding the foreign matter, the polyester composition of the present invention has a number density of particles containing titanium element and having a maximum diameter of 1 μm or more (hereinafter referred to as titanium element-containing particles) that is less than 5,000 per 1 mg of the polyester composition. preferable. When the number density is 5,000 or more, when the polyester film is used, the surface roughness may become rough or the transparency of the film may be impaired.

  The polyester film of the present invention may have a single layer structure, but is preferably a laminated polyester film including at least one layer containing the polyester composition of the present invention. In this case, a laminated polyester film in which a layer containing the polyester composition of the present invention is laminated on one surface is preferable. More preferably, both surfaces are composed of the above polyester composition. Moreover, since the polyester film of the present invention contains almost no foreign matter, it has excellent surface flatness. The film surface average roughness Ra is preferably 0.5 to 30 nm, more preferably 1 to 20 nm, and particularly preferably 1 to 10 nm.

  Moreover, an iron compound, an aluminum compound, a zinc compound, a tin compound, or the like may be added for the purpose of improving the color tone of the resulting polymer or the heat resistance of the polymer.

  In addition to pigments such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin and carbon black, additives such as anti-coloring agents, stabilizers and antioxidants may be included. .

  The polyester compositions of the present invention are also listed in optical brighteners such as “Plastics Additives Handbook”, Ed. R. Gacher and H. Muller, Hanser verlag, 3rd Ed., 1990 P775-789 ”. It is also possible to improve the color tone by adding such a fluorescent brightening agent.

  Furthermore, organic and inorganic blue pigments such as azo, triphenylmethane, quinoline, methine, dioxazine, quinacridone, anthraquinone and phthalocyanine, organic and inorganic blue dyes, and organic and inorganic red pigments Further, a color adjusting agent composed of one or more organic or inorganic red dyes can be added.

  Next, the manufacturing method of the polyester composition of this invention is demonstrated. Although the example of a polyethylene terephthalate is described as a specific example, it is not limited to this.

  Polyethylene terephthalate is usually produced by one of the following processes. (1) A process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by direct esterification reaction, and a high molecular weight polymer is obtained by subsequent polycondensation reaction, and (2) dimethyl terephthalate and ethylene glycol are used as raw materials. In this process, a low polymer is obtained by a transesterification reaction, and a high molecular weight polymer is obtained by a subsequent polycondensation reaction. Here, the esterification reaction proceeds even without a catalyst, but the aforementioned titanium compound may be added as a catalyst. In the transesterification reaction, a catalyst such as manganese, calcium, magnesium, zinc, lithium or the above titanium compound is used as a catalyst, and the catalyst used in the reaction after the transesterification reaction is substantially completed. In order to inactivate, a phosphorus compound is added.

  The production method of the present invention comprises various additions to the low polymer obtained in any stage of the series of reactions (1) or (2), preferably in the first half of the series of reactions (1) or (2). After the product is added, the above-described titanium compound is added as a polycondensation catalyst and a polycondensation reaction is performed to obtain a high molecular weight polyethylene terephthalate.

  Further, the above reaction can be applied to a batch, semi-batch, or continuous system.

  The above-described polyester composition can be suitably used as a film.

  Especially, it is preferable to set it as the laminated film which has a main layer and a sublayer. The laminated film can be produced by, for example, melting polyesters (A) and (B), respectively. In this case, the melting temperature is not particularly limited and may be any temperature that does not hinder the extrusion of the polyesters (A) and (B) from the die. Next, both the melted polyesters (A) and (B) are laminated to form a laminated sheet. The lamination method is a method in which polyesters (A) and (B) are joined and laminated from the extruder to the die or in the die, and are discharged from the die as a laminated sheet, so-called co-extrusion method, or different slit shapes The polyester (A) and (B) may each be discharged from the die of the sheet in the form of a sheet, and both may be laminated, but the coextrusion method is preferred. In addition, although the polyester (A) and (B) should just be laminated | stacked at least as for the layer structure of a lamination sheet, (A) / (B) two-layer structure or (A) / (B) / (A) , (B) / (A) / (B). In particular, a three-layer structure is preferable. At this time, the polyester of the present invention may be formed alone, or the polyester composition of the present invention may be mixed with 1% by weight or more of the other polyester composition to obtain a film having a changed metal concentration. From the viewpoint of improving the productivity and heat resistance of other varieties.

  As the coextrusion lamination method, a field block, a static mixer, a multi-manifold die, or the like can be used. Examples of the static mixer include a pipe mixer and a square mixer. In the present invention, it is preferable to use a square mixer. Moreover, it is preferable from a foreign material viewpoint that the layer which consists of a polyester resin composition of this invention comprises at least one surface.

  The laminated sheet thus obtained is taken up by various moving cooling bodies, preferably a rotating drum, and an electrostatic charge is deposited on the sheet and cooled and solidified by the moving cooling body. Any method may be used for depositing an electrostatic charge on the sheet. For example, a method of applying a voltage between the wire electrode and the moving cooling body by providing a wire electrode in the vicinity between the base and the moving cooling body and on the sheet surface on the side where the sheet does not contact the moving cooling body Can be used. The cooled and solidified laminated sheet, that is, the unstretched sheet is then stretched uniaxially or biaxially by various stretching methods such as a roll stretching method or a tenter stretching method and wound up. The order of stretching may be either sequential or simultaneous.

  Here, stretching in the longitudinal direction refers to stretching for imparting a molecular orientation in the longitudinal direction to the film. For example, this stretching performed by the difference in the peripheral speed of the roll may be performed in one step, or a plurality of You may carry out in multiple steps using a roll pair. The stretching ratio is preferably 2 to 15 times, more preferably 2.5 to 7 times.

  Stretching in the transverse direction refers to stretching for giving the film an orientation in the width direction. For example, the film is stretched in the width direction by using a tenter while gripping both ends of the film with clips. The stretching ratio is preferably 2 to 10 times.

  In the case of simultaneous biaxial stretching, the film is stretched simultaneously in the longitudinal direction and the lateral direction while being conveyed while being gripped by clips in the tenter, and this method may be used.

  The biaxially stretched film is preferably subjected to a heat treatment at a temperature not lower than the stretching temperature and not higher than the melting point in the tenter in order to impart flatness and dimensional stability. After uniform cooling, the film is cooled to room temperature and wound. In the film of the present invention, the heat treatment temperature is preferably 120 to 240 ° C. from the viewpoints of flatness and dimensional stability.

  Although the thickness of the laminated polyester film of this invention is not specifically limited, Preferably it is 0.5-100 micrometers, Especially 1-80 micrometers is preferable.

  In addition, when forming an easy-adhesion layer, particle layer, etc., the coating components may be applied in-line before stretching or between longitudinal stretching and lateral stretching using a coating technique such as gravure coating or metering bar. It is also possible to perform off-line coating after stretching.

  The polyester composition and the polyester film of the present invention are particularly suitable as a base film for capacitors and a base film for electrical insulation. In addition, a base film for photography, a base film for vapor deposition, a base film for packaging, and a base film for adhesive tape. Also, it can be suitably used for a magnetic tape base film and an optical base film.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the physical-property value in an Example was measured by the method described below.

(1) Content of titanium element, phosphorus element, antimony element and manganese element in polyester Using a fluorescent X-ray element analyzer (manufactured by Horiba, Ltd., MESA-500W type), 8 g of polymer is melted and formed into a plate shape. Then, the intensity of the fluorescent X-ray was measured. This value was converted into metal content using a calibration curve prepared in advance with a sample with known content.

(2) Intrinsic viscosity of polymer IV
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.

(3) Melting point 10 mg of the polyester composition was precisely weighed, sealed using an aluminum open pan and pan cover, and from 20 ° C. under a nitrogen stream using a differential scanning calorimeter (Perkin Elmer, DSC7 type). The temperature was raised to 285 ° C. at a rate of 16 ° C./min, and the melting point peak temperature observed along the way was taken as the melting point.

(4) Number of coarse foreign matters in the polyester composition (number density of titanium element-containing particles)
In a Class 100 clean room, the chip was ultrasonically cleaned with (concentrated hydrochloric acid: pure water = 1: 1) for 1 minute, then ultrasonically cleaned with pure water for 1 minute, and then melted on the cover glass on the hot plate. Then, a sample was prepared by placing a cover glass so that air bubbles would not enter, and 4 fields of view were measured by a dark field method (450 times) using a Keyence digital microscope (VHZ-450), and the average was observed. The polymer thin film on the slide was cut with 10 rows × 10 columns with a sharp razor to make a total of 100 squares. A defect having a maximum diameter of 1 μm or more was judged as a foreign substance. Foreign matter in a 0.02 mg chip with a visual field area of 0.0034 cm ² and a thickness of 40 μm is measured. Further, after the preparation was subjected to plasma ashing treatment of the polymer thin film portion, carbon deposition was performed, and the cells containing particles counted as 1 μm or more were observed with an optical microscope with SEM-XMA, and titanium contained in the particles. The presence or absence of elements was confirmed. Thus, the numerical value which converted the number of the particle | grains 1 micrometer or more containing a titanium element per mg of polymer was made into the particle number density.

(5) Solution haze About 2 g of the sample to be measured is dissolved in 20 mL of orthochlorophenol, and analysis is performed by an integrating sphere photoelectric photometry method using a haze meter (HGM-2DP type, manufactured by Suga Test Instruments Co., Ltd.). It was. In addition, in order to remove the influence of inorganic particles such as titanium oxide particles in the target polyethylene terephthalate, the same pretreatment as described in the above (1) was performed to obtain a polymer.

  If the solution haze is less than 1%, the content of foreign matter is small, and it can be said that the polymer has excellent film forming properties.

(6) Color tone of polymer Using a color difference meter (SM color computer format SM-3) manufactured by Suga Test Instruments Co., Ltd., it was measured as a Hunter value (L, a, b value).

(7) Polymer gelation rate (%)
About 2 g of polymer chips were frozen and ground with a freezer mill, sieved with # 42 (350 μm or less), dried under reduced pressure (100 ° C., 40 minutes, pressure 133 Pa), weighed (1.0 ± 0.01 g), and then heat treated (2 5 hours, 300 ° C., in air) at a flow rate of 100 ml / min).

  After heat treatment, dissolve at 80 ° C x 0.5 hr (orthochlorophenol), filter through glass filter (3G3), wash with about 50-100 ml of dichloromethane, and dry under reduced pressure (110 ° C x 2.0 hr, pressure 133 Pa) Then, the filtered material on the filter was weighed, and the gelation rate (%) with respect to the weight of the treated polymer was calculated.

(8) Number of coarse projections H1 and H2 of the film
After ^two measurement surfaces (50 cm ² ) are stacked and brought into close contact with each other by electrostatic force (applied voltage 5.4 kV), the height of the coarse protrusion from the Newton ring caused by the interference of the coarse protrusion light between the two films. The number of coarse protrusions of a single ring or more was H1, and the number of coarse protrusions of a double ring or more was H2. The light source used was a halogen lamp with a 564 nm bandpass filter.

However, when measurement is difficult with the measurement area, the measurement area may be changed as appropriate and converted to 100 cm ² . (For example, a measurement area of 1 cm ² is measured for 50 visual fields and converted to 100 cm ^2. )
In addition, when measurement by the above method is difficult, a three-dimensional roughness meter (SE-3AK manufactured by Kosaka Laboratory: scans in the film width direction under the following conditions and performs measurement 50 times. Radius of tip of stylus is 2 μm. Using a stylus load of 0.07 g, a measurement area width of 0.5 mm × length of 15 mm (pitch of 0.1 mm), and a cutoff value of 0.08 mm), the number of protrusions having a height of 0.28 μm or more and a height of 0. H1 and H2 may be obtained by measuring the number of protrusions of 56 μm or more and converting it to 100 cm ² . Furthermore, if necessary, various methods for measuring the number of protrusions on the surface of the film such as an atomic force microscope (AFM) and a 4-detection SEM may be used in combination.

(9) Volume Specific Resistance Using two copper plates as electrodes, an electrode with a copper plate of 22 cm ² and a copper plate interval of 9 mm is prepared with a Teflon (registered trademark) spacer in between. This electrode was immersed in a polymer melted at 290 ° C., and the resistance value was calculated from the amount of current when a voltage of 5,000 V was applied between the electrodes.

(10) Casting property by applying electrostatic force A 6 kv DC voltage is applied between the electrode placed on the melt-extruded film and the rotating cooling body, the casting speed is gradually increased, and the casting speed when application unevenness occurs ( m / min) and was determined according to the following criteria. B or higher was accepted.

60 m / min or more S
50 to less than 60 m / min A
40 to less than 50 m / min B
30 to less than 40 m / min C
Less than 30 m / min D
(11) Surface roughness Ra
Measurement was performed according to JIS-B0601. Specifically, it measured using the high precision thin film level | step difference meter ET-10 made from Kosaka Laboratory. The stylus tip radius was 0.5 μm, the needle pressure was 5 mg, the measurement length was 1 mm, and the cutoff was 0.08 mm.

Catalyst A. Citric acid chelate titanium compound synthesis method Citric acid monohydrate (532 g, 2.52 mol) was dissolved in warm water (371 g) in a 3 L flask equipped with a stirrer, a condenser and a thermometer. To this stirred solution was slowly added titanium tetraisopropoxide (285 g, 1.00 mol) from the addition funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution from which the isopropanol / water mixture was distilled under reduced pressure. The product was cooled to a temperature below 70 ° C., and a 32 wt / wt% aqueous solution of NaOH (380 g, 3.04 mol) was slowly added via a dropping funnel to the stirred solution. The resulting product was filtered and then mixed with ethylene glycol (504 g, 80 mol) and heated under reduced pressure to remove isopropanol / water and a slightly cloudy light yellow product (Ti content 3 .85% by weight). This was designated Catalyst A. Catalyst A contains 3.04 moles of sodium elemental titanium.

Catalyst B. Method for synthesizing a lactate chelate titanium compound Titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 2 L flask equipped with a stirrer, a condenser and a thermometer was added from an addition funnel to ethylene glycol (218 g, 3 .51 mol) was added. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. The reaction mixture was stirred for 15 minutes and an 85 wt / wt% aqueous solution of ammonium lactate (252 g, 2.00 mol) was added to the reaction flask to give a clear pale yellow product (Ti content 6.54 wt. %). This was designated Catalyst B.

Catalyst C. Method for Synthesizing Titanium Alkoxide Compound Titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer was added from a dropping funnel to ethylene glycol (496 g, 8. 00 mol) was added. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. To the reaction flask, a 32 wt / wt% aqueous solution of NaOH (125 g, 1.00 mol) was slowly added via a dropping funnel to give a clear yellow liquid (Ti content 4.44 wt%). This was designated Catalyst C. Catalyst C contains the same amount of sodium element as titanium.

Catalyst D. Method for synthesizing titanium alkoxide compound (mixed mono, di, and tributyl phosphate) To titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer Ethylene glycol (496 g, 8.00 mol) was added from the dropping funnel. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. To the reaction flask, a 32 wt / wt% aqueous solution of NaOH (125 g, 1.00 mol) was slowly added via a dropping funnel to give a clear yellow liquid (Ti content 4.44 wt%). Mono, di, and tributyl phosphoric acid (210 g, 1.00 mol) was added to the mixed solution to obtain a titanium compound containing a phosphorus compound (P content: 2.49% by weight). This was designated Catalyst D. Catalyst D contains the same mole of sodium element as titanium.

Reference Example 1 (Production of colloidal silica particles)
4 parts by weight of saturated aqueous ammonia was mixed with 40 parts by weight of ethyl alcohol, and 4 parts by weight of 4 pentyl silicon was added while stirring this to obtain colloidal silica having an average particle size of 0.1 μm. Next, 100 parts by weight of ethylene glycol was added and heated to distill off ethyl alcohol and water to obtain an ethylene glycol slurry of colloidal silica.

Example 1
Production of polyethylene terephthalate A slurry of 100 parts by weight of high-purity terephthalic acid (manufactured by Mitsui Chemicals) and 43 parts by weight of ethylene glycol (manufactured by Nippon Shokubai Co., Ltd.) was previously charged with about 120 parts by weight of bis (hydroxyethyl) terephthalate, and the temperature was 250 ° C. The esterification reaction tank maintained at a pressure of 1.2 × 10 ⁵ Pa was sequentially supplied over 4 hours, and after the completion of the supply, the esterification reaction was further performed over 1 hour. The part was transferred to a polycondensation tank.

  Subsequently, 0.01 parts by weight of ethyl diethylphosphonoacetate is added to the polycondensation reaction tank to which the esterification reaction product has been transferred, 0.03 part by weight of magnesium acetate tetrahydrate, and further catalyst A is added. It added so that it might become 8 ppm as a titanium element. Next, the colloidal silica ethylene glycol slurry prepared in Reference Example 1 was added so that the particle concentration in the polymer would be 0.1%.

  Thereafter, while stirring the low polymer, the reaction system was gradually heated from 250 ° C. to 285 ° C. and the pressure was reduced to 100 Pa. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain polymer pellets. The time from the start of decompression to the arrival of the predetermined stirring torque was 3 hours.

  The obtained polymer had an IV of 0.63, a melting point of 259 ° C., and a solution haze of 0.4%. The content of titanium atoms derived from the titanium catalyst measured from the polymer is 8 ppm, the content of phosphorus atoms is 10 ppm, the content of magnesium element is 30 ppm, Ti / P = 0.52, and the content of antimony atoms The amount was confirmed to be 0 ppm.

The volume specific resistance when the pellets were melted was 80 MΩ · cm.
The polyethylene terephthalate resin was dried with a vacuum dryer and supplied to an extruder. The polyethylene terephthalate resin is melted at 280 ° C. with an extruder, passed through a gear pump and a filter, supplied to a T-die and formed into a sheet, and then electrostatically applied with a wire-like electrode, with a surface temperature of 20 ° C. It was rapidly cooled and solidified on a casting drum kept at a low temperature.

  The obtained cast film was heated in a roll group set at 90 ° C., stretched 3.0 times in the longitudinal direction, led to a tenter, preheated with hot air at 100 ° C., and stretched 3.3 times in the lateral direction. The stretched film was heat-treated with hot air at 200 ° C. in a tenter as it was, and after gradually cooling to room temperature, it was wound up. The thickness of the obtained film was 10 μm.

  The results of evaluating the properties of the obtained film are shown in Table 1.

Examples 2-6
A polyester resin and a film were obtained in the same manner as in Example 1 except that the amount and type of titanium catalyst to be added, the amount of alkaline earth metal compound, and the amount of phosphorus element added were changed. The results are shown in Table 1.

Comparative Example 1
A polyester resin and a film were obtained in the same manner as in Example 1 except that the titanium catalyst to be added was changed to the catalyst A, and the alkaline earth metal compound amount and the phosphorus element addition amount were changed. The results are shown in Table 1.

Comparative Example 2
A polyester resin was obtained in the same manner as in Example 1 except that the amount of titanium element contained in the polyethylene terephthalate resin was 50 ppm. The solution haze of the polymer was as high as 3.1%, and the base stain was generated during spinning, the base stain was generated during film formation, the base streaks were generated, and tearing occurred frequently, resulting in poor operability.

Comparative Example 3
A polyester resin was obtained by polymerization in the same manner as in Example 1 except that antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was added to the catalyst in an amount of 100 ppm in terms of antimony atoms with respect to the resulting polymer. Even if the catalyst is changed, the polymerization reactivity remains good, but the solution haze of the polymer obtained is as high as 3.1%, the base stains occur during film formation, the base streaks occur, and tears occur frequently. It was inferior in operability.

Example 7
Except for the addition of colloidal silica using two extruders, the polyester resin polymerized in the same manner as in Example 1 and the polyester resin used in Comparative Example 3 were respectively extruded and laminated in two layers with a feed block. Then, the sheet was formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 20 ° C. while electrostatically applying a wire electrode. The obtained cast film was heated with a roll group set at 90 ° C., stretched 3.0 times in the longitudinal direction, led to a tenter, preheated with hot air at 100 ° C., and stretched 3.3 times in the lateral direction. The stretched film was heat-treated with hot air at 200 ° C. in a tenter as it was, gradually cooled to room temperature and wound up. The lamination ratio of the obtained film was 90% (weight ratio) for the polyester resin of Example 1 and 10% for the polyester resin of Comparative Example 3. The results are shown in Table 1.

Claims (10)

A titanium compound having 0.5 to 30 ppm in terms of titanium atomic weight based on the polyester composition containing at least one selected from the group consisting of the functional groups represented by formulas (1) to (6) as a substituent, The alkali metal compound contains 0 to 80 ppm as an alkaline earth metal atomic weight, and phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphine oxide, phosphonous acid, phosphinic acid, phosphine, phosphate, phosphate Containing at least one compound selected from the group consisting of phyto, phosphonate and phosphinate, the content of alkali metal element being Ma (mol / g), and the content of alkaline earth metal element being Md (mol / g) ), When the content of phosphorus element is Mp, Ma, Md and Mp satisfy the following formula: Ether composition.
Ma + 2 × Md + 1 ≧ Mp × 3

(However, in Formula (1)-Formula (5), R < ¹ > -R < ³ > is each independently any group shown below. Hydrogen C1-C30 organic group) The titanium compound has a functional group represented by formula (1) to formula (3) as a substituent, and R ^{1 to} R ³ in formula (1) to formula (3) are each independently hydrogen or carbon number 1 The polyester composition according to claim 1, which is ˜30 organic groups. In formula (1) to formula (3), at least one substituent of R ^{1 to} R ³ is hydrogen or a hydroxyl group, or an alkyl group, alkoxy group, hydroxyl group, carbonyl group, acetyl group, carboxyl group The polyester composition according to claim 2, which is an organic group having 1 to 30 carbon atoms and having at least one functional group selected from the group consisting of a group, an ester group and an amino group. The titanium compound has a functional group represented by the formula (1) as a substituent, and at least one substituent of R ^{1 to} R ³ in the formula (1) is hydrogen, or an alkyl group, a carboxyl group, and The polyester composition according to claim 1, which is an organic group having 1 to 30 carbon atoms and having at least one functional group selected from the group consisting of ester groups. The polyester composition according to claim 1, wherein the titanium compound has a functional group represented by the formula (4) as a substituent, and R ¹ in the formula (4) is an organic group having 1 to 30 carbon atoms. The polyester composition according to any one of claims 1 to 5, wherein a volume resistivity value at the time of melting is 1 x 10 ⁶ Ω · cm to 1 x 10 ⁹ Ω · cm. The polyester composition according to claim 1, wherein the number density of particles containing titanium element having a maximum diameter of 1 μm or more is less than 5,000 / mg. The polyester film containing the polyester composition in any one of Claims 1-7. A laminated polyester film comprising at least one layer of the polyester film according to claim 8. A magnetic recording medium comprising the laminated polyester film according to claim 9.