JPWO2017061415A1 - Polyester composition for masterbatch, polyester composition for film, and polyester film - Google Patents

Abstract

The present invention has a sufficiently low melting specific resistance, each containing a specific amount of a polyester, a magnesium compound, an alkali metal compound, a specific phosphorus compound, and a lubricant each having a dicarboxylic acid component and a glycol component as components, It is a polyester composition for masterbatch excellent in stability. By mixing this polyester composition for masterbatch, it is possible to improve the film-forming property by increasing the electrostatic adhesion to the cooling drum, and to provide the optimum slipperiness, and to produce a polyester film with excellent quality. It becomes possible to provide.

Description

  The present invention relates to a polyester composition for a masterbatch for imparting good electrostatic adhesion to a polyester film to improve film formability and imparting slipperiness and workability.

  Polyesters are excellent in mechanical properties and chemical properties, and are used in a wide range of fields such as films and sheets for packaging, magnetic tape, and optics. The polyester film is obtained by biaxial stretching after melt extrusion of polyester. That is, the sheet-like material melt-extruded by the extruder is brought into close contact with the surface of the rotating cooling drum and cast (casting), and then the sheet-like material is led to a drawing roll arranged at the subsequent stage of the cooling drum. The film is stretched and further stretched in the transverse direction with a tenter, followed by heat setting. Here, in order to increase the uniformity of the thickness of the film and increase the casting speed, when the sheet-like material melt-extruded from the extrusion die is cooled on the surface of the rotary cooling drum, the sheet-like material and the drum surface And must be in close contact with sufficiently high adhesion. For this reason, as a method for increasing the adhesion between the sheet-like material and the surface of the rotating drum, a wire-like electrode is provided between the extrusion die and the cooling rotating drum, and a high voltage is applied to the unsolidified sheet. A so-called electrostatic contact casting method is often used in which static electricity is generated on the surface of the object, and the sheet-like object is electrostatically attached to the surface of the cooling drum and rapidly cooled.

  In the electrostatic contact casting method, in order to improve electrostatic adhesion to the cooling drum of the sheet material, it is effective to increase the amount of charge on the surface of the sheet material, and to increase the amount of charge, It is known that it is effective to modify the polyester as a raw material to lower its melt specific resistance. As a method for lowering the melt specific resistance, an alkali metal or alkaline earth metal compound is added during the esterification or transesterification reaction in the production stage of the raw material polyester (for example, Patent Documents). 1).

  As another method for lowering the melt specific resistance, a large amount of alkali metal or alkaline earth metal compound is added to separately produce a master batch having a very low melt specific resistance and mixed with the polyester used as the raw material of the film. (For example, refer to Patent Document 2). However, in the production of a masterbatch, there are problems that foreign substances are easily generated by adding a large amount of an alkali metal or alkaline earth metal compound, a problem that coloring tends to occur, and a problem that thermal stability is lowered. Further, a sufficiently low melting specific resistance cannot be obtained as a master batch, and it is necessary to mix a large amount of the master batch with the polyester of the film material, which is disadvantageous in terms of cost.

  Polyester for film adheres when the films are overlapped, causing so-called blocking, or when processing a roll-shaped film, defects such as scratches may occur due to poor sliding properties with guide rolls, etc. There is a problem to do. In order to solve such a problem in handling the film, a method in which inert particles such as inorganic particles are contained inside the polyester is effective.

JP 2010-285527 A JP 2008-201822 A

  The object of the present invention is to provide a masterbatch polyester composition having a sufficiently low melt specific resistance and excellent color tone and thermal stability, and mixing the masterbatch polyester composition with a static resistance to a cooling drum. The object is to provide a polyester film that is excellent in quality by improving electro-adhesion to improve film-forming property and imparting optimum slipperiness.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention.

That is, this invention consists of the following structures.
[1] A polyester composition comprising a polyester comprising a dicarboxylic acid component and a glycol component, a magnesium compound, an alkali metal compound, a phosphorus compound, and a lubricant, wherein the phosphorus compound is a trialkyl phosphate, It is at least one selected from the group consisting of a phosphorus compound in which the alkyl group of the alkyl ester is an alkyl group having 2 to 4 carbon atoms, and ethyl diethylphosphonoacetate, and satisfies the following (1) to (4) A polyester composition for a master batch.
(1) The polyester composition contains 400 to 2,700 ppm of magnesium atoms, 40 to 270 ppm of alkali metal atoms, and 200 to 1,700 ppm of phosphorus atoms in terms of mass. (2) The average particle size of the polyester composition is 0. (3) The amount of magnesium atom is m (mol%) and the amount of alkali metal atom is k (mol) with respect to the dicarboxylic acid component constituting the polyester. %), Where the amount of phosphorus atoms is p (mol%), satisfying formula I 2 ≦ (m + k / 2) /p≦3.5 (formula I)
(4) The polyester composition for a masterbatch according to [1], wherein the melt specific resistance ρi satisfies 0.005 × 10 ^{8 to} 0.05 × 10 ⁸ Ω · cm [2] The alkali metal is potassium.
[3] The phosphorous compound according to any one of [1] and [2], wherein the phosphorus compound is a phosphoric acid trialkyl ester, and the alkyl group of the alkyl ester is an alkyl group having 2 to 4 carbon atoms. Polyester composition for masterbatch.
[4] The polyester composition for a masterbatch according to any one of [1] and [2], wherein the phosphorus compound is triethyl phosphate.
[5] A polyester composition for a film containing the masterbatch polyester composition according to any one of [1] to [4].
[6] A polyester film comprising the polyester composition for film according to [5].

  The polyester composition for a masterbatch of the present invention is manufactured by adding a specific amount of a magnesium compound, an alkali metal compound, a phosphorus compound and a lubricant, and has a low melt specific resistance, so that the film-forming property of the film using this is improved. In addition, since it has few foreign substances and has excellent color tone and thermal stability, and excellent slipperiness during film formation, it can be used in a wide range of applications such as packaging films and industrial films.

FIG. 1 is a graph showing the relationship between the amount of metal and the melt specific resistance in Examples and Comparative Examples.

[Masterbatch polyester composition]
The polyester composition for masterbatch of this invention turns into the polyester composition for films by mixing with the polyester resin for film raw materials.
The melt specific resistance (ρi) of the polyester composition for masterbatch of the present invention needs to be 0.005 × 10 ^{8 to} 0.05 × 10 ⁸ Ω · cm. The melt specific resistance can be measured by the method described in the Examples section described later. In order to improve the film formability of the polyester film, the melt specific resistance as the polyester composition for film is preferably 0.1 × 10 ^{8 to} 0.3 × 10 ⁸ Ω · cm. When the melt specific resistance of the polyester composition is higher than 0.05 × 10 ⁸ Ω · cm, it is necessary to add a large amount of the master batch to improve the film forming property of the polyester for film. As a result, there are problems such as an increase in manufacturing cost. If the melt specific resistance of the masterbatch polyester composition is lower than 0.005 × 10 ⁸ Ω · cm, the added amount of the masterbatch becomes too small and segregation is likely to occur, resulting in unevenness in the melt specific resistance of the film. The film forming stability may decrease. The melt specific resistance of the polyester composition for a masterbatch is more preferably 0.005 × 10 ^{8 to} 0.025 × 10 ⁸ Ω · cm.

  A magnesium compound and an alkali metal compound are added to the polyester composition for a masterbatch of the present invention in order to lower the melt specific resistance. In addition, these metal ion components are presumed to form salts and form foreign substances by reacting with carbonyl end groups of unreacted dicarboxylic acid components and oligomer components. A phosphorus compound is added to disperse the resin and improve thermal stability. When this foreign material aggregates, it may become a coarse defect (coarse particle) in the film obtained using the polyester composition for masterbatches.

  As the magnesium compound used in the present invention, a known magnesium compound can be used. For example, lower fatty acid salts such as magnesium acetate, alkoxides such as magnesium methoxide and the like may be used, and these may be used alone or in combination of two or more. In particular, magnesium acetate is preferable.

  The amount of magnesium atoms is 400-2700 ppm with respect to the masterbatch polyester composition. When the magnesium atomic weight is less than 400 ppm, the melt specific resistance becomes high, and a large amount of masterbatch is required to improve the film-forming property of the polyester composition for film. There are problems such as increased costs. When the amount of magnesium atoms exceeds 2700 ppm, the amount of insoluble foreign matter (magnesium salt) produced is increased, and the heat resistance is lowered, resulting in severe coloration of the film. A preferable amount of magnesium atoms is 450 to 2500 ppm, and a more preferable amount of magnesium atoms is 450 to 2000 ppm.

  Examples of the alkali metal of the alkali metal compound used in the present invention include lithium, sodium and potassium. In addition, examples of the alkali metal compound include lower fatty acid salts such as lithium acetate and potassium acetate, alkoxides such as potassium methoxide, and the like. More than one species may be used in combination. As the alkali metal, potassium is preferable because it has a large effect of lowering the melt specific resistance. As the alkali metal compound, acetate is preferable, and potassium acetate is particularly preferable.

  The amount of alkali metal atoms is 40 to 270 ppm with respect to the masterbatch polyester composition. When the amount of alkali metal atoms is less than 40 ppm, the melt specific resistance becomes high, and a large amount of polyester for masterbatch is required to improve the film forming property of the polyester composition for film. However, there is a problem such as low manufacturing cost. When the amount of the alkali metal atom exceeds 270 ppm, the heat resistance is lowered, and the film is severely colored. A preferable amount of alkali metal atoms is 45 to 250 ppm, and a more preferable amount of alkali metal atoms is 45 to 200 ppm.

  Examples of the phosphorus compound usable in the present invention include phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid, phosphinic acid, and ester compounds thereof. For example, phosphoric acid, trimethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, monobutyl phosphate, dibutyl phosphate, phosphorous acid, trimethyl phosphite, tributyl phosphite, methylphosphonic acid Dimethyl methylphosphonate, dimethyl ethylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, diphenyl phenylphosphonate, ethyl diethylphosphonoacetate, phosphinic acid, methylphosphinic acid, dimethylphosphinic acid, phenylphosphinic acid, diphenylphosphinic acid, Examples include methyl dimethylphosphinate and methyl diphenylphosphinate. Among these, in order to express the effects of the present invention to a high degree, the phosphorus compound is a phosphoric acid trialkyl ester, and the alkyl group of the alkyl ester is a C 2-4 alkyl group, And at least one selected from the group consisting of ethyl diethylphosphonoacetate. Especially, it is preferable to use the phosphoric acid triester which has a C2-C4 alkyl group. Specific examples include triethyl phosphate, tripropyl phosphate, tributyl phosphate and the like, and these may be used alone or in combination of two or more. Triethyl phosphate is particularly preferred because it is considered to form a complex having a moderately strong interaction with magnesium ions, and a polyester composition having a low melting specific resistance, a small amount of foreign matter, and an excellent color tone can be obtained.

  The quantity of a phosphorus atom is 200-1700 ppm with respect to the polyester composition for masterbatches. When the amount of phosphorus atoms is less than 200 ppm, the effect of stabilizing magnesium ions and alkali metal ions and dispersing them in the polyester is reduced, and the amount of insoluble foreign matter produced is increased. Furthermore, since magnesium that has become a foreign substance has no effect of lowering the melting specific resistance, the melting specific resistance becomes higher than the amount of magnesium added. In addition, the heat resistance is lowered, and the film is undesirably colored. If the amount of phosphorus atoms exceeds 1700 ppm, the excess phosphorus compound interacts with magnesium ions, so the charge of magnesium ions does not contribute to the effect of lowering the melt resistivity, and the melt resistivity increases with respect to the amount of magnesium added, It is not preferable. A preferable amount of phosphorus atoms is 220 to 1000 ppm.

A lubricant is added to the polyester composition for masterbatch of the present invention for the purpose of improving the handling characteristics of the film. Lubricants are inert particles such as inorganic particles, and when added, they form irregularities on the surface during film formation, and give the film runnability, slipperiness, winding property, workability, etc. .
Examples of the lubricant used in the present invention include titanium, aluminum, silicon, calcium, magnesium, barium and other metal oxides, carbonates, silicates, sulfates and aluminates. For example, particles such as titanium dioxide, alumina, aluminosilicate, silicon dioxide (silica), calcium oxide, calcium carbonate, barium sulfate, and other natural sources such as talc, mica, kaolinite, and zeolite can be raised, but not limited thereto. .

The average particle size of the lubricant is 0.5 to 3.0 μm, more preferably 0.8 to 2.5 μm. If it is less than 0.5 μm, it is not preferable because unevenness is formed on the surface and the effect of imparting handling properties such as slipping property and running property is lowered. On the other hand, if the thickness exceeds 3.0 μm, the quality of the film may be impaired by the formation of coarse protrusions, which is not preferable. The average particle size of the lubricant is measured using a laser light scattering type particle size distribution meter as described in the Examples section.
The amount of the lubricant is 7000 to 20000 ppm based on the mass of the masterbatch polyester composition. When mixing with the polyester resin for film raw material to make a polyester composition for film, the polyester composition for masterbatch is added so that the amount of lubricant becomes a preferable amount. When the lubricant is less than 7000 ppm, a large amount of the masterbatch polyester composition is added, resulting in poor color tone and heat resistance. Moreover, since the effectiveness as a masterbatch is low, it leads to the increase in manufacturing cost. When the lubricant exceeds 20000 ppm, the amount of metal in the polyester composition for film is reduced, the melt specific resistance is increased, and the film forming property is deteriorated, which is not preferable. Further, aggregation of the lubricant occurs during the polymerization, leading to an increase in the number of coarse defects (coarse particles) after dilution of the blend, which is not preferable. The lower limit of the content of the lubricant is preferably 8000 ppm or more, more preferably 10,000 ppm or more, and further preferably 12000 ppm or more. The upper limit of the content is preferably 18000 ppm or less.

The contents of magnesium atom, alkali metal atom, phosphorus atom, and lubricant in the masterbatch polyester composition can be quantified by the method described in the Examples section below. The timing of adding the magnesium compound, alkali metal compound, and phosphorus compound to the polyester is not particularly limited, but the polyester is polymerized, particularly during the esterification (or transesterification) step, or the esterification (or transesterification) step. By adding from the time when the polycondensation process is started until the polycondensation process starts, it is possible to prevent the acid component of the polyester and magnesium ions or alkali metal ions from forming a salt to form a foreign substance, and uniformly in the oligomer. This is preferable because it can be dispersed. The timing of addition of the lubricant to the polyester is not particularly limited, but the polycondensation step may be performed during the polymerization of the polyester, particularly in the middle of the esterification (or transesterification) step, or from the end of the esterification (or transesterification) step. It is preferable to add it before the start because it can be uniformly dispersed in the oligomer.
When these compounds are added during the polymerization of polyester, magnesium atoms and alkali metal atoms remain in the polyester composition almost as they are added, but phosphorus atoms may be distilled out of the polymerization system under reduced pressure. Therefore, it is necessary to determine the addition amount of the phosphorus compound after grasping the relationship between the addition amount and the remaining amount in advance. Almost all of the lubricant remains in the polyester composition as it is.

When the polyester is a polyester having a dicarboxylic acid component and a glycol component as constituent components, the amount of magnesium atoms relative to the dicarboxylic acid component is m (mol%), the amount of alkali metal atoms is k (mol%), and the amount of phosphorus atoms When p is mol%, the molar ratio of magnesium atom, alkali metal atom, and phosphorus atom satisfies the following formula I, whereby the effect of the present invention can be obtained.
2 ≦ (m + k / 2) /p≦3.5 (Formula I)
It is considered that the phosphorus atom stabilizes magnesium ions and alkali metal ions without making them foreign. Since the magnesium ion is divalent while the alkali metal ion is monovalent, the sum of the amount of magnesium ion and alkali metal ion is expressed as (m + k / 2), and the ratio “( m + k / 2) / p "is the relative amount of magnesium ion and alkali metal ion with respect to the phosphorus atom.
When the value of “(m + k / 2) / p” exceeds 3.5, the amount of phosphorus atoms is relatively small with respect to magnesium atoms and alkali metal atoms, and magnesium ions and alkali metal ions are stabilized. And the amount of insoluble foreign matter (magnesium salt, alkali metal salt) produced increases. Furthermore, since magnesium that has become a foreign substance has no effect of lowering the melting specific resistance, the melting specific resistance becomes higher with respect to the amount of magnesium added. Further, the heat resistance is lowered, and the film is severely colored. When the value of “(m + k / 2) / p” is less than 2, the amount of phosphorus atoms is excessive relative to magnesium atoms and alkali metal atoms, and excess phosphorus compounds interact with magnesium ions. Therefore, the charge of magnesium ions does not contribute to the effect of lowering the melting specific resistance, and the melting specific resistance becomes higher with respect to the amount of magnesium added. “(M + k / 2) / p” is more preferably 2.3 or more and 3 or less, and further preferably 2.5 or more and 3 or less.
“(M + k / 2) / p” in Formula I can also be calculated from the content of each atom in the masterbatch polyester composition.

Similarly to the above, when the amount of magnesium atoms is m (mol%) and the amount of alkali metal atoms is k (mol%), the relationship between the metal amount (total amount of magnesium atoms and alkali metal atoms) and the melt specific resistance. When the following formula II is satisfied, it is considered that the added metal does not become a foreign substance and contributes to a decrease in the melt specific resistance (ρi), and the polyester composition for a masterbatch of the present invention has the formula II. Fulfill.
R <1.2 × 10 ⁻² / (m + k / 2) (Formula II)
(Where R = ρi × 10 ⁻⁸ )
Magnesium compounds and alkali metal compounds have the effect of lowering the melt resistivity, and since magnesium ions are divalent while alkali metal ions are monovalent, the amount of magnesium ions and alkali metal ions (M + k / 2) is a factor that greatly affects the melt resistivity.
When the added metal is converted into a foreign substance, the metal converted into a foreign substance hardly contributes to the melting specific resistance, so that the melting specific resistance is higher than that of a system in which no foreign substance is formed. Therefore, when it deviates from Formula II, the fusion specific resistance with respect to the amount of added metal is high, and there is a possibility that the metal which has become foreign matters is increased. In general, it can be said that the amount of metal and the value of the melt specific resistance are in an inversely proportional relationship. FIG. 1 is a graph plotting the relationship between the amount of metal (m + k / 2) and the value of melting specific resistance (ρi) in Examples 1 to 9 and Comparative Examples 1 to 5 described later. In the figure, the example is represented by “◇” and the comparative example is represented by “●”. From this figure, it can be seen that the range in which the effect of the present invention is obtained is a range below the curve. Since this curve is a curve of R = 1.2 × 10 ⁻² / (m + k / 2), the above formula II was derived.

  The polyester according to the present invention is a polyester having a dicarboxylic acid component and a glycol component as constituent components. The dicarboxylic acid component and the glycol component can be used singly or in combination. In addition to dicarboxylic acids, polyhydric alcohols may be included in addition to polycarboxylic acids and glycols. Alternatively, a unit comprising a hydroxycarboxylic acid or a cyclic ester may be included.

  The polyester can be produced by a conventionally known method. For example, in the case of polyester comprising terephthalic acid and ethylene glycol, a method of polycondensation after esterification of terephthalic acid and ethylene glycol, or transesterification of an alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol After performing, any method of polycondensation can be performed. The polymerization apparatus may be a batch type or a continuous type.

As the catalyst, metal-containing polyester polycondensation catalysts such as antimony compounds, aluminum compounds, titanium compounds, tin compounds, and germanium compounds known as polyester polymerization catalysts can be used. Among these, it is preferable to use an aluminum compound which is excellent in foreign matter suppression and thermal stability.
The polyester composition for masterbatch of this invention contains the polymerization catalyst component. When using an antimony compound, it is preferable to contain 50-300 ppm as an antimony atom in mass conversion in the polyester composition for masterbatches. When using an aluminum compound, it is preferable to contain 20-100 ppm as an aluminum atom in mass conversion in the polyester composition for masterbatches. When using a titanium compound, it is preferable to contain 5-150 ppm as a titanium atom in mass conversion in the polyester composition for masterbatches. When using a tin compound, it is preferable to contain 50-200 ppm as a tin atom in mass conversion in the polyester composition for masterbatches. When using a germanium compound, it is preferable to contain 50-200 ppm as a germanium atom in mass conversion in the masterbatch polyester composition. Among these metal polymerization catalysts, in the case of antimony compounds, aluminum compounds, titanium compounds, and tin compounds, almost the added amount remains in the polyester composition as it is, but in the case of germanium compounds, the polymerization system is not used under reduced pressure. Therefore, it is desirable to adjust the addition amount so that the residual amount in the polyester composition falls within the above range.

  The polyester polymerization catalyst can be added to the reaction system at any stage of the polymerization reaction. For example, it can be added to the reaction system at any stage before and during the esterification reaction or transesterification reaction, immediately before the start of the polycondensation reaction, or at any stage during the polycondensation reaction.

  Examples of the dicarboxylic acid include succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1, 3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid, etc. Saturated aliphatic dicarboxylic acids exemplified herein, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid, etc., or ester-forming derivatives thereof, orthophthalic acid, isophthalic acid, Terephthalic acid 5- (alkali metal) sulfoisophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalene Dicarboxylic acid, 4,4′-biphenyl dicarboxylic acid, 4,4′-biphenyl sulfone dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, Examples thereof include aromatic dicarboxylic acids exemplified by pamonic acid and anthracene dicarboxylic acid, and ester-forming derivatives thereof.

  As polyvalent carboxylic acids other than these dicarboxylic acids, ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, And ester-forming derivatives thereof.

  Examples of the glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1 , 4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexane Alkylene glycols such as dimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, Aliphatic glycols exemplified by reethylene glycol, polytrimethylene glycol, polytetramethylene glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis ( β-hydroxyethoxyphenyl) sulfone, bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A , Bisphenol C, 2,5-naphthalenediol, and glycols obtained by adding ethylene oxide to these glycols, and the like.

  Examples of polyhydric alcohols other than these glycols include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol and the like.

  Examples of the hydroxycarboxylic acid include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 4-hydroxycyclohexanecarboxylic acid, or These ester-forming derivatives are exemplified.

  Examples of the cyclic ester include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

  Examples of ester-forming derivatives of polyvalent carboxylic acids or hydroxycarboxylic acids include these alkyl esters, acid chlorides, acid anhydrides, and the like.

  As the polyester used in the present invention, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, poly (1,4-cyclohexanedimethylene terephthalate), polyethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate and copolymers thereof are preferable. Particularly preferred are polyethylene terephthalate and copolymers thereof.

In the polyester composition for masterbatch of the present invention, depending on the purpose of use, diethylene glycol inhibitor, fluorescent brightener, color tone adjusting agent such as dye or pigment, ultraviolet ray inhibitor, infrared absorbing dye, heat stabilizer, One or more kinds of various additives such as a surfactant and an antioxidant can be contained. Basic compounds such as alkylamine compounds and ammonium salt compounds can be used as diethylene glycol inhibitors, and antioxidants such as aromatic amines and phenols can be used as antioxidants. A stabilizer such as sulfur or amine can be used.
These additives can be added to the polyester composition for a master batch in a ratio of preferably 10% by mass or less, more preferably 5% by mass or less.

In the masterbatch polyester composition of the present invention, the color tone (Co-b) in the pellet is preferably 0 to 40, and more preferably 0 to 30. The polyester composition for a master batch is mixed with the polyester resin for a film raw material to form a polyester composition for a film and is formed into a film. Even if the color tone (Co-b) in the pellets of the masterbatch polyester composition is a relatively high value, there is no problem as long as it is diluted with the polyester resin for film raw material and the color tone as a film is in a preferable range.
The intrinsic viscosity (IV) of the masterbatch polyester composition of the present invention is preferably 0.3 to 0.7 dl / g. The polyester composition for a master batch is mixed with the polyester resin for a film raw material to form a polyester composition for a film and is formed into a film. Even if the intrinsic viscosity (IV) in the pellet of the polyester composition for the masterbatch is a relatively high value or a low value, the intrinsic viscosity (IV) as a film is preferably diluted with the polyester resin for the film raw material. If so, no problem.

[Polyester composition for film, polyester film]
The polyester composition for a film of the present invention is a mixture of the above-mentioned polyester composition for a master batch and a polyester resin for film raw material (composition) in an arbitrary ratio. A polyester film can be obtained from the polyester composition for a film of the present invention using a known film forming method.
The polyester resin for film raw material (composition) may or may not contain an alkali metal compound or an alkaline earth metal compound for lowering the melt specific resistance. When the polyester composition for a masterbatch of the present invention is mixed with a polyester resin for a film material that does not contain an alkali metal compound or an alkaline earth metal compound and has a high melting specific resistance, a general polyester composition for a film and Equivalent film forming properties can be achieved. When the polyester composition for a master batch of the present invention is mixed with a polyester composition for a film raw material that already contains an alkali metal compound or an alkaline earth metal compound, the film forming property can be further improved.
The polyester that can be used for the polyester resin for film raw material (composition) is the same as the polyester that can be used for the polyester composition for masterbatch. It is a preferable aspect that the polyester used for the polyester resin for film raw material (composition) and the polyester used for the polyester composition for masterbatch are polyesters composed of the same components.
It is desirable that the magnesium atomic weight in the polyester composition for film is 15 to 150 ppm, the alkali metal amount is 1.5 to 15 ppm, and the phosphorus atomic weight is 7 to 80 ppm. Specifically, it is preferable to use a polyester composition for a film containing 1 to 20% by mass of the polyester composition for masterbatch of the present invention, and for a film containing 2 to 10% by mass of the polyester composition for masterbatch. A polyester composition is more preferable. When the masterbatch polyester composition is mixed in such a range, a film having an excellent balance of melt specific resistance, color tone, and heat resistance can be obtained. The color tone (Co-b) in the film is preferably 0 to 6, more preferably 0 to 5.2, and more preferably 0 to 5 when measured by the method described in the Examples section. More preferably.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The main characteristic value measurement methods will be described below.

(1) Intrinsic viscosity of polyester resin / composition (IV)
The polyester composition (polyester resin) was dissolved using a 6/4 (weight ratio) mixed solvent of phenol / 1,1,2,2-tetrachloroethane and measured at a temperature of 30 ° C.

(2) Melt specific resistance Two electrodes (stainless steel wire with a diameter of 0.6 mm) are placed on both ends of the polyester composition melted at 275 ° C., and sandwiched between two quartz plates with a width of 2 cm. A layer of a uniform molten polyester composition having a thickness of 2 cm and a thickness of 0.6 mm was formed, and a current (io) when a DC voltage of 120 V was applied was measured at a temperature of 280 ° C., and this was applied to the following equation: The melting specific resistance value ρi (Ω · cm) was determined.
ρi (Ω · cm) = (A / L) × (V / io)
[A: electrode area (cm ² ), L: distance between electrodes (cm), V: voltage (V)]
A (cm ² ) = [width of molten polyester composition layer] × [thickness] = 2 (cm) × 0.06 (cm), and V = 120 (V). L is a value measured without including the diameter of the electrode and is 1.3 cm.

(3) Quantitative determination method of aluminum, magnesium, potassium, lithium and phosphorus The sample composition was prepared by heating and melting the polyester composition to [melting point + 20 ° C.] in a stainless steel circular ring having a thickness of 5 mm and an inner diameter of 50 mm. The amount of elements was determined by line analysis and displayed in ppm (mass basis). In quantification, a calibration curve obtained in advance from a sample with a known amount of each element was used.

(4) Color tone (Co-b)
Using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., ZE-2000), the color difference (L, a, b) of the pellets or film of the polyester composition was measured. The pellet was placed in a measurement cell and measured by a reflection method. Ten films were stacked and measured by the reflection method.

(5) Heat resistance The polyester film formed by mixing the polyester composition for masterbatch was put into a glass ampule, and after replacing with nitrogen, the glass ampule was sealed under reduced pressure (nitrogen atmosphere) of 13.3 kPa, Intrinsic viscosities before and after heat treatment were measured at 300 ° C. for 2 hours. The heat resistance is indicated by a decrease in intrinsic viscosity due to heat treatment (ΔIV = [IV after heat treatment] − [IV before heat treatment]). Usually, the intrinsic viscosity is lowered by heat treatment, so the smaller the absolute value of ΔIV, the better the heat resistance.

(6) Number of coarse defects The number of coarse defects was determined by measuring particles in a cast film observed using a phase-contrast optical microscope (Nikon) and an objective lens (manufactured by the company, magnification 10 times, aperture 0.5). The size and the number of particles are measured by image analysis from the above images. These particles are mainly those in which a lubricant is aggregated, and those in which foreign matters derived from magnesium ions and alkali metal ions are aggregated are also included. In the image analysis, the number of aggregated particles of 10 μm or more is measured, 20 times are measured while changing the field of view, the total number of aggregated particles is obtained, and the number of aggregated particles of 10 μm or more per 1 square mm of visual field area The number of coarse defects was calculated. When the number of coarse defects was less than 300, it was judged as ○, and when 300 or more, it was judged as ×.

(7) Average Particle Size of Lubricant Using a laser light scattering particle size distribution meter (Leeds & Northrup, Microtrac HRA model 9320-X100), the ethylene glycol slurry of the lubricant was diluted with water and measured substantially in an aqueous system. The 50% cumulative volume diameter of the measurement results was taken as the average particle diameter.

Reference Example 1 Production of Polyester Resin (X) for Film Raw Material 0.54 parts by weight of terephthalic acid, ethylene glycol, and antimony trioxide were charged into a stainless steel autoclave equipped with a stirrer, a distillation tower, and a pressure regulator. Furthermore, 0.3 mol% of triethylamine was added to the terephthalic acid as a diethylene glycol inhibitor, and the esterification reaction was carried out for 2 hours while sequentially removing water produced during esterification at 240 ° C. and a gauge pressure of 0.35 MPa.
Subsequently, the temperature of the system is raised to 280 ° C. over 1 hour, and during this time, the pressure of the system is gradually reduced to 150 Pa. Under these conditions, a polycondensation reaction is performed for 1 hour, and the polyester resin (X ) The obtained polyester resin had an intrinsic viscosity of 0.62 dl / g and a melt specific resistance of 3.2 × 10 ⁸ Ω · cm.

Example 1
(1) Preparation of silica slurry 5 liters of ethylene glycol and 750 g of silica particles having an average particle size of 2.4 μm (Silicia 310, manufactured by Fuji Silysia Chemical Co., Ltd.) are placed in a homogenizer-equipped dispersion tank, and stirred and dispersed at 8000 rpm for 2 hours. l slurry.
(2) Production of polyester composition for masterbatch Terephthalic acid and ethylene glycol were charged into a stainless steel autoclave equipped with a stirrer, a distillation tower, and a pressure regulator. Charge the silica slurry to 16,000 ppm with respect to the theoretical amount of polyester, add triethylamine to 0.3 mol% with respect to terephthalic acid, and perform an esterification reaction according to a conventional method to obtain an oligomer. It was.
Subsequently, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, 100 ppm as potassium atoms, and 660 ppm as phosphorus atoms with respect to the theoretical amount of polyester. The temperature of the system is raised to 280 ° C. in 1 hour, and the pressure of the system is gradually reduced to 150 Pa during this time, and a polycondensation reaction is carried out for 80 minutes under these conditions. A pellet of the composition was obtained. Table 1 shows the physical properties of the obtained polyester composition. Aluminum atoms, magnesium atoms, and potassium atoms were added as they were, but the phosphorus atoms were partially distilled out of the polymerization system in the polycondensation reaction step. The remaining amount (content) decreased (the same applies to the following examples).
(3) Film formation of polyester film The pellets of the polyester composition for masterbatch produced above and the pellets of the polyester resin for film raw material (X) are mixed at a mass ratio of 5:95, and at 135 ° C. for 10 hours. Vacuum dried. Next, a fixed amount was supplied to a twin-screw extruder, melted and extruded into a sheet at 280 ° C., and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 20 ° C. to obtain a cast film having a thickness of 1400 μm.
Next, this cast film was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a peripheral speed difference to obtain a uniaxially oriented film. Subsequently, the film was stretched 4.0 times in the width direction at 120 ° C. with a tenter and heated with an infrared heater at 260 ° C. for 0.5 seconds, and further 3% at 200 ° C. for 23 seconds. The biaxially oriented polyester film having a thickness of 100 μm was obtained. The properties of the obtained film are shown in Table 1. The number of coarse defects was measured with a cast film.

(Example 2)
In the polymerization method of Example 1, silica slurry, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate are respectively 8000 ppm as silica, 30 ppm as aluminum atoms, and magnesium atoms with respect to the theoretical amount of polyester. As in Example 1, pellets of a polyester composition for a masterbatch were obtained in the same manner as in Example 1 except for adding 500 ppm as a potassium atom, 50 ppm as a potassium atom, and 330 ppm as a phosphorus atom. Table 1 shows the physical properties of the obtained polyester composition.
The obtained polyester composition for master batch and the pellet of polyester resin (X) for film raw material were mixed at a mass ratio of 10:90, and a polyester film was formed in the same manner as in Example 1. The properties of the obtained film are shown in Table 1.

(Example 3)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 80 ppm as aluminum atoms, 2500 ppm as magnesium atoms, 250 ppm as potassium atoms, based on the theoretical amount of polyester, A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added to 1650 ppm. Table 1 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

Example 4
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and 250 ppm as potassium atoms with respect to the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 530 ppm. Table 1 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Example 5)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and tripropyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and 100 ppm as potassium atoms with respect to the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 660 ppm. Table 1 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Example 6)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, lithium acetate dihydrate, and triethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, lithium, based on the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 90 ppm as an atom and 660 ppm as a phosphorus atom were added. Table 1 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Example 7)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and ethyldiethylphosphonoacetate were 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and potassium atoms as the theoretical amount of polyester, respectively. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 100 ppm and 660 ppm as a phosphorus atom were added. Table 1 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Example 8)
In the polymerization method of Example 1, silica slurry, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 12,000 ppm as silica, 60 ppm as aluminum atom, and magnesium atom as the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 1000 ppm, 100 ppm as a potassium atom, and 660 ppm as a phosphorus atom were added. Table 1 shows the physical properties of the obtained polyester composition.
The obtained polyester composition for masterbatch and the pellet of the polyester resin for film raw material (X) were mixed at a mass ratio of 6.7: 93.3, and a polyester film was formed in the same manner as in Example 1. Went. The properties of the obtained film are shown in Table 1.

Example 9
In the polymerization method of Example 1, silica slurry, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate are respectively 18000 ppm as silica, 60 ppm as aluminum atom, and magnesium atom as the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 1000 ppm, 100 ppm as a potassium atom, and 660 ppm as a phosphorus atom were added. Table 1 shows the physical properties of the obtained polyester composition.
The obtained polyester composition for masterbatch and the pellet of polyester resin (X) for film material were mixed at a mass ratio of 4.4: 95.6, and a polyester film was formed in the same manner as in Example 1. Went. The properties of the obtained film are shown in Table 1.

(Comparative Example 1)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and 100 ppm as potassium atoms relative to the theoretical amount of polyester, A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added to 400 ppm. Table 2 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 2.

(Comparative Example 2)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 30 ppm as aluminum atoms, 500 ppm as magnesium atoms, and 50 ppm as potassium atoms with respect to the theoretical amount of polyester, A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 660 ppm. Table 2 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 2.

(Comparative Example 3)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 60 ppm as aluminum atoms, 2000 ppm as magnesium atoms, and 50 ppm as potassium atoms with respect to the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 660 ppm. Table 2 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 2.

(Comparative Example 4)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and triethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and 1000 ppm as potassium atoms relative to the theoretical amount of polyester, A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 660 ppm. Table 2 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Comparative Example 5)
In the polymerization method of Example 1, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and trimethyl phosphate were each 60 ppm as aluminum atoms, 1000 ppm as magnesium atoms, and 100 ppm as potassium atoms relative to the theoretical amount of polyester, A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that the phosphorus atom was added so as to be 660 ppm. Table 2 shows the physical properties of the obtained polyester composition.
The film was obtained by the same method as in Example 1. The properties of the obtained film are shown in Table 1.

(Comparative Example 6)
In the polymerization method of Example 1, silica slurry, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and trimethyl phosphate are respectively 5000 ppm as silica, 60 ppm as aluminum atom, and magnesium atom as the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 1000 ppm, 100 ppm as a potassium atom, and 660 ppm as a phosphorus atom were added. Table 2 shows the physical properties of the obtained polyester composition.
The obtained polyester composition for master batch and the pellet of the polyester resin for film raw material (X) were mixed at a mass ratio of 16:84, and a polyester film was formed in the same manner as in Example 1. The properties of the obtained film are shown in Table 2.

(Comparative Example 7)
In the polymerization method of Example 1, silica slurry, basic aluminum acetate, magnesium acetate dihydrate, potassium acetate, and trimethyl phosphate are respectively 30000 ppm as silica, 60 ppm as aluminum atom, and magnesium atom as the theoretical amount of polyester. A pellet of a polyester composition for a masterbatch was obtained in the same manner as in Example 1 except that 1000 ppm, 100 ppm as a potassium atom, and 660 ppm as a phosphorus atom were added. Table 2 shows the physical properties of the obtained polyester composition.
The obtained polyester composition for masterbatch and the pellet of the polyester resin for film raw material (X) were mixed at a mass ratio of 2.7: 97.3, and a polyester film was formed in the same manner as in Example 1. Went. The properties of the obtained film are shown in Table 2.

The polyester compositions for master batches of Examples 1 to 9 have a low melting specific resistance and a small amount of foreign matters, and the color tone and thermal stability of films obtained using the polyester compositions are excellent. Further, by satisfying the above formula II, it is considered that the added metal does not become a foreign substance and contributes to a decrease in melting specific resistance (ρi). Compared to Example 6 using lithium as the alkali metal, Example 1 using potassium has a lower melting specific resistance and an excellent color tone. Compared to Example 7 using ethyldiethylphosphonoacetate as the phosphorus compound, Examples 1 and 5 using phosphoric acid trialkyl ester (alkyl group having 2 to 4 carbon atoms) have excellent color tone. Yes. Compared to Example 5 using tripropyl phosphate, Example 1 using triethyl phosphate has a lower melting specific resistance.
The polyester composition for masterbatch of Comparative Example 1 has a relatively low phosphorous compound content (the ratio of (m + k / 2) / p is large), so the color tone is poor compared to Example 1 where the amount of magnesium is the same. The heat resistance of the obtained film is poor. In Comparative Example 2, it can be said that since the content of the phosphorus compound is relatively large (the ratio of (m + k / 2) / p is small), the melt specific resistance is high and the film forming property is poor. In Comparative Example 3, since the total amount of magnesium and alkali metal is relatively large (the ratio of (m + k / 2) / p is large), the color tone is poor. In Comparative Example 4, since the content of the potassium compound is large, the color tone is worse than in Example 1, and the heat resistance of the obtained film is poor. In Comparative Example 5, trimethyl phosphate is used as the phosphorus compound, but it can be said that the melt specific resistance is high and the film forming property is poor. In Comparative Example 6, since the amount of lubricant as a master batch is small, a large amount of master batch is added to the film, so the color tone as a film is poor. In Comparative Example 7, it can be said that since the amount of lubricant as a master batch is large, the addition amount of the master batch is small, the melt specific resistance as a film is low, and the film forming property is poor. In addition, since a large amount of lubricant is added during the polymerization of the masterbatch, the number of coarse defects is large.

  The polyester composition for masterbatch of the present invention has a sufficiently low melt specific resistance, few foreign matters, and excellent color tone and thermal stability. There is an effect that it is possible to produce a polyester film which is improved and imparts optimum slipperiness and is excellent in quality. Therefore, the film using the polyester composition for masterbatch of the present invention is, for example, an antistatic film, an easily adhesive film, a card, a dummy can, an agricultural, a building material, a cosmetic material, a wallpaper, an OHP Near infrared absorption for film, printing, inkjet recording, sublimation transfer recording, laser beam printer recording, electrophotographic recording, thermal transfer recording, thermal transfer recording, printed circuit board wiring, membrane switch, plasma display Transparent conductive film for film, touch panel and electroluminescence, masking film, photoengraving, X-ray film, photographic negative film, retardation film, polarizing film, polarizing film protection (TAC), polarizing plate, Protection film and / or separator film for retardation plate inspection It can be used for the photosensitive resin film, for field expansion film, diffusion sheets, reflection films, antireflection films, ultraviolet ray prevention, for example, for back grinding tape, a wide range of applications.

Claims (6)

A polyester composition comprising a polyester comprising a dicarboxylic acid component and a glycol component, a magnesium compound, an alkali metal compound, a phosphorus compound, and a lubricant, wherein the phosphorus compound is a trialkyl phosphate, and the alkyl ester Wherein at least one selected from the group consisting of a phosphorus compound in which the alkyl group is an alkyl group having 2 to 4 carbon atoms and ethyl diethylphosphonoacetate, the following (1) to (4) are satisfied: A polyester composition for a masterbatch.
(1) The polyester composition contains 400 to 2,700 ppm of magnesium atoms, 40 to 270 ppm of alkali metal atoms, and 200 to 1,700 ppm of phosphorus atoms in terms of mass. (2) The average particle size of the polyester composition is 0. (3) The amount of magnesium atom is m (mol%) and the amount of alkali metal atom is k (mol) with respect to the dicarboxylic acid component constituting the polyester. %), Where the amount of phosphorus atoms is p (mol%), satisfying formula I 2 ≦ (m + k / 2) /p≦3.5 (formula I)
(4) The melt specific resistance ρi satisfies 0.005 × 10 ^{8 to} 0.05 × 10 ⁸ Ω · cm.   The polyester composition for a masterbatch according to claim 1, wherein the alkali metal is potassium.   The masterbatch polyester according to any one of claims 1 and 2, wherein the phosphorus compound is a phosphoric acid trialkyl ester, and the alkyl group of the alkyl ester is an alkyl group having 2 to 4 carbon atoms. Composition.   The polyester composition for a masterbatch according to claim 1, wherein the phosphorus compound is triethyl phosphate.   The polyester composition for films containing the polyester composition for masterbatches in any one of Claims 1-4. A polyester film comprising the polyester composition for a film according to claim 5.