JP6772747B2 - Polyethylene terephthalate resin composition and a film comprising it - Google Patents

Description

The present invention relates to a polyethylene terephthalate resin composition and a film comprising the same. More specifically, the present invention relates to a polyethylene terephthalate resin composition having a small amount of fine foreign substances and gelled substances at the time of melting and having good electrostatic immobility, and a film made of the same.

Since the polyethylene terephthalate resin composition has excellent mechanical and chemical properties, it has high industrial value and is widely used for fibers, films, sheets, hollow molded products and the like.

In particular, a film using a polyethylene terephthalate resin composition has excellent mechanical properties, thermal properties, chemical resistance, electrical properties, etc., and therefore is used for magnetic recording media, capacitors, optics, etc. It is widely used for industrial purposes such as industrial use.

Generally, a polyester film is obtained by melt-extruding a polyethylene terephthalate resin with an extruder and then biaxially stretching it in the vertical and horizontal directions. However, the polyester film is melted at a temperature of 250 to 300 ° C., which is higher than the melting point of the polyethylene terephthalate resin. Because it is extruded by extrusion, gel-like foreign matter is generated by thermal decomposition of polyethylene terephthalate resin or oxidative decomposition when oxygen is mixed, which causes defects in the molded film.

Further, when forming a polyethylene terephthalate resin into a film, an electrostatic application casting method is often adopted in which a high voltage is applied to the upper surface of an uncured sheet-like material to bring the sheet-like material into close contact with a rotary cooling drum. If the speed of the rotary cooling drum is increased in order to increase the film forming speed in the electrostatic application casting method, the adhesion between the sheet-like material and the rotary cooling drum decreases, and the thickness uniformity and transparency of the film decrease. , Causes defects on the film surface due to uneven application.

In particular, in recent years, films for magnetic recording media and dry film resists are required to have a high degree of surface smoothness and thinning, and it is necessary to extremely reduce defects in the film, and the above-mentioned gel-like foreign matter and static electricity are required. Poor electrical applicability is not preferable because it deteriorates the formation of defects and transparency of the film surface.

For example, Patent Documents 1 and 2 propose a method of adding a large amount of an alkali metal compound, an alkaline earth metal compound, and a phosphorus compound to polyester as a method for improving electrostatic applicability. However, although this method can improve the electrostatic applicability to some extent, since it uses a large amount of magnesium acetate, there is a problem that gel-like foreign matter or foreign matter derived from a metal compound is generated and the transparency is deteriorated.

As a method of suppressing gel-like foreign matter generated during melt extrusion, Patent Document 3 states that the molar ratio (M / P) with alkali metal, alkaline earth metal element, and phosphorus element contained in polyester is adjusted. A method has been proposed. However, since this method uses magnesium acetate, it is insufficient to reduce the gelation rate for a longer period of time.

Japanese Unexamined Patent Publication No. 2006-2492113 Japanese Unexamined Patent Publication No. 2008-201822 Japanese Unexamined Patent Publication No. 2003-96280

An object of the present invention is to solve these conventional problems and to provide a polyethylene terephthalate resin composition having a small amount of fine foreign substances and gelled substances at the time of melting and having good electrostatic applicability, and a polyester film made of the same.

The above-mentioned problems include manganese compounds, potassium compounds and phosphorus compounds, the content (ppm) of each element satisfies the following (1) to (4), and the content of magnesium element in the polyethylene terephthalate resin is 1 ppm. less than, the melting specific resistance is 1.0 × 10 ⁷ Ω · cm or less, a polyethylene terephthalate resin composition 300 ° C. oxygen concentration of 1% in 6 hours molten percent gelation time is characterized in that it is a 5-15% Achieved by.

500 ≤ Mn ≤ 900 ... (1)
20 ≦ K ≦ 80 ・ ・ ・ (2)
6.25 ≤ Mn / K ≤ 45 ... (3)
3 ≦ (Mn + K / 2) / P ≦ 20 ・ ・ ・ (4)

The polyethylene terephthalate resin composition of the present invention provides a polyethylene terephthalate resin composition having a small amount of fine foreign substances and gelled substances at the time of melting and having good electrostatic applicability, and a polyester film made of the same.

Examples of the constituent components of the polyethylene terephthalate resin composition of the present invention include terephthalic acid as a dicarboxylic acid component or an acid component mainly composed thereof, and ethylene glycol as a diol component or a glycol component mainly composed of the same.

Further, the polyethylene terephthalate resin composition in the present invention contains one or more dicarboxylic acids other than terephthalic acid and the acid component mainly composed of the terephthalic acid as a copolymerization component as long as it is 20 mol% or less of the carboxylic acid component. Similarly, if it is 20 mol% or less of the glycol component, one or two or more kinds of glycol components other than ethylene glycol or a glycol component mainly composed of the ethylene glycol can be contained as a copolymerization component. Further, a polyfunctional compound having trifunctionality or higher may be contained as a copolymerization component as long as the thermoplasticity is not impaired.

The polyethylene terephthalate resin composition of the present invention must contain a manganese compound, a potassium compound and a phosphorus compound, and the content of each element must satisfy the following formulas (1) to (4).

500 ≤ Mn ≤ 900 ... (1)
20 ≦ K ≦ 80 ・ ・ ・ (2)
6.25 ≤ Mn / K ≤ 45 ... (3)
3 ≦ (Mn + K / 2) / P ≦ 20 ・ ・ ・ (4)
The polyethylene terephthalate resin composition of the present invention has a manganese element content in the range of 500 to 900 ppm, more preferably in the range of 600 to 800 ppm. When the content of manganese element is 500 ppm or more, the volume resistance of the polyethylene terephthalate resin composition becomes low, the electrostatic applicability during film molding is improved, and when it is 900 ppm or less, the gelation rate and minute foreign substances increase. It is preferable that the transparency of the obtained polymer (solution haze) is also good.

The polyethylene terephthalate resin composition of the present invention has a potassium element content in the range of 20 to 80 ppm, more preferably in the range of 35 to 65 ppm. When the content of the potassium element is 20 ppm or more, the electrostatic applicability during film molding is improved, and when it is 80 ppm or less, the transparency (solution haze) of the polymer is deteriorated due to the formation of internal particles by potassium. Preferred to prevent.

In the polyethylene terephthalate resin composition of the present invention, the ratio of the amounts of each element of the manganese compound and the potassium compound and the value of Mn / K are in the range of 6.25 to 45, and more preferably 13 to 38. When the value of Mn / K is in the range of 6.25 to 45, it is preferable to suppress the increase of minute foreign substances generated by the thermal decomposition of the polymer.

In the polyethylene terephthalate resin composition of the present invention, the ratio of the amounts of each element of the manganese compound, the potassium compound, and the phosphorus compound, and the value of (Mg + K / 2) / P are in the range of 3 to 20, and further in the range of 7 to 15. Is preferable. When the value of (Mg + K / 2) / P is 3 or more, the electrostatic applicability at the time of film forming is improved, and when it is 20 or less, the increase in the gelation rate can be suppressed, which is preferable.

The polyethylene terephthalate resin composition of the present invention has a magnesium element content of less than 1 ppm, more preferably less than 0.5 ppm. When the content of the magnesium element is less than 1 pp, it is preferable to suppress an increase in the gelation rate at the time of remelting, and it is preferable to suppress a gelled product generated during the polymerization reaction.

The polyethylene terephthalate resin composition of the present invention has a melt specific resistance of 1.0 × 10 ⁷ Ω · cm or less, and more preferably 0.8 × 10 ⁷ Ω · cm or less. If the melt specific resistance is not more than 1.0 × 10 ⁷ Ω · cm, the adhesion between the rotating cooled drum is increased in the electrostatic casting method, it can proceed smoothly film molding, the thickness of the resulting film It is preferable because the uniformity and transparency are improved.

The polyethylene terephthalate resin composition of the present invention has a gelation rate in the range of 5 to 15% when melted at 300 ° C. and an oxygen concentration of 1% for 6 hours, and more preferably in the range of 8 to 12%. When it is 5% or more and 15% or less, it is preferable to suppress an increase in defects on the film surface.

The polyethylene terephthalate resin composition of the present invention has a solution haze of 2.5% or less, more preferably 2.0% or less. When it is 2.5% or less, the transparency of the film becomes good, and it becomes possible to obtain a film suitable for magnetic recording medium applications and dry film resist applications.

Specific examples of the method for producing the polyethylene terephthalate resin composition of the present invention will be described below.
For example, the polyethylene terephthalate resin composition can be produced by a process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by a direct esterification reaction, and then a high molecular weight polymer is obtained by a polycondensation reaction. Alternatively, it can be produced by a process using dimethyl terephthalate and ethylene glycol as raw materials, obtaining a low polymer by a transesterification reaction, and further obtaining a high molecular weight polymer by a subsequent polymerization reaction. In the present invention, any method can be adopted. Further, if necessary, a heat-resistant stabilizer, an electrostatic agent, an antifoaming agent, an antioxidant and the like can be added before and during the reaction.

Examples of the manganese compound include acetate, propionic acid salt, chloride, bromide, iodide, hydroxide and the like. Among these, manganese acetate is preferably used from the viewpoint of gelation rate and solution haze.

Examples of the method for adding the manganese compound include powder or ethylene glycol slurry, ethylene glycol solution, and aqueous solution, but from the viewpoint of solution haze, addition in a mixed solution of water and ethylene glycol is preferable.

Examples of the potassium compound include acetate, propionic acid salt, chloride, bromide, iodide, hydroxide and the like, and among these, potassium hydroxide is preferably used from the viewpoint of minute foreign substances.

Examples of the phosphorus compound include phosphoric acid, phosphorous acid, phosphonic acid and ester compounds thereof, and a phosphoric acid ester is particularly preferably used. Examples of the phosphoric acid ester include trimethylphosphonoacetate, triethylphosphonoacetate, methyldiethylphosphonoacetate, ethyldiethylphosphonoacetate and the like, but triethylphosphonoacetate is preferably used from the viewpoint of gelation rate and fine foreign matter. ..

Examples of the elemental magnesium compound include acetate, propionic acid salt, chloride, bromide, iodide, and hydroxide.

The method for adding a manganese element, a potassium element, a phosphorus element, and a magnesium element to the polyethylene terephthalate resin composition of the present invention is not particularly limited, but it is preferably added at the time of producing polyethylene terephthalate.

The intrinsic viscosity of the polyethylene terephthalate resin composition can be determined by the stirring torque of the polymer at the end point of the melt polymerization, and the end point determination torque of the melt polymerization apparatus may be set so as to obtain the desired intrinsic viscosity.
After that, the obtained molten polyethylene terephthalate can be produced in a polyethylene terephthalate resin composition by a method of discharging the molten polyethylene terephthalate from a mouthpiece into a strand shape, cooling the mixture, and pelletizing the molten polyethylene terephthalate with a cutter.

The obtained polyethylene terephthalate resin composition is preferably pre-crystallized before solid-phase polymerization. For pre-crystallization, a method of applying a mechanical impact to the polyethylene terephthalate resin composition to perform a shearing treatment, a method of performing a heat treatment under hot air flow, or the like can be adopted.

The polyethylene terephthalate resin composition of the present invention can be blended with a polyethylene terephthalate resin composition having insufficient electrostatic application castability. As the polyethylene terephthalate resin composition having insufficient electrostatically applied castability, the content of alkali metal element and alkaline earth metal element is low or not contained, and the polyethylene terephthalate resin composition containing phosphorus element, alkali metal element and alkali. Examples thereof include a polyethylene terephthalate resin composition containing precipitated particles composed of at least one earth metal element and phosphorus element, and the composition includes a manganese element content of 25 to 220 ppm with respect to the weight in the entire layer of the polyester film. The mixture is blended so that the molar ratio (M / P) of the metal element and the phosphorus element is 1.5 to 4.0.

The content of the manganese element in the entire layer of the polyester film is further preferably 45 to 200 ppm. When the content of the manganese element is 25 to 220 ppm, the generation of gel at the time of melting can be suppressed, which is preferable.

The M / P is further preferably in the range of 2.0 to 3.5. When the M / P is 1.5 or more, the electrostatic application castability at the time of film molding is improved, and when it is 4.0 or less, the generation of gel at the time of melting can be suppressed, which is preferable.

Among the above metal compounds, for example, the alkali metal compound has a monovalent valence, and the alkaline earth metal compound is a divalent metal compound. Since M in the present invention defines the molar ratio represented by M / P with reference to a divalent metal compound, when metal compounds having different valences are used, the valence is taken into consideration in the calculation. To. For example, when an alkali metal compound is used, M / P is calculated with the value obtained by multiplying the number of moles of the alkali metal compound by 0.5 as M.

The blending amount of the polyethylene terephthalate resin composition of the present invention is not particularly limited, but is in the range of 0.1 to 30% with respect to the weight of the entire layer of the polyester film after blending, and further 1 to 20%. Is preferable. When it is 0.1% or more, the electrostatic castability is improved, and when it is 30% or less, the slipperiness of the obtained polyester film is not impaired when blended in the polyethylene terephthalate resin composition containing particles. Can be used for.

The polyethylene terephthalate resin composition of the present invention can be molded into a polyester film by the following method.

For example, after vacuum-drying the polyethylene terephthalate resin composition, it is supplied to an extruder, melted at 260 to 300 ° C., extruded into a sheet from a T-shaped mouthpiece, and has a surface temperature of 10 to 60 using an electrostatic application casting method. It is wound around a mirror casting drum at ° C. and cooled and solidified to prepare an unstretched polyester film.

The unstretched film is stretched 2.5 to 5 times in the longitudinal direction between rolls heated to 70 to 130 ° C. At least one side of this film may be subjected to a corona discharge treatment to apply a coating liquid or the like. Subsequently, it was continuously stretched 2.5 to 5 times in the width direction in a heated hot air zone of 70 to 150 ° C., then led to a heat treatment zone of 190 to 240 ° C., heat-treated for 5 to 40 seconds, and 100. Crystal orientation is completed through a cooling zone of ~ 200 ° C. Further, during the heat treatment, a relaxation treatment of 0.1 to 12% may be performed in the width direction or the longitudinal direction, if necessary.

The polyethylene terephthalate resin composition obtained in the present invention contains few fine foreign substances and gelled substances when melted, and has good electrostatic immobility. Therefore, it can be used as a film for IT-related applications such as magnetic recording media and dry film resists. Can be suitably used.

The present invention will be specifically described below with reference to examples. The method for measuring physical properties and the method for evaluating the effect were as follows.

(1) Content of metal element Quantification was performed by atomic absorption spectrometry.

(2) Melt resistivity An electrode is prepared by sandwiching a Teflon (registered trademark) spacer between two copper plates as electrodes, and this electrode is submerged in a polyethylene terephthalate resin composition melted at 290 ° C. between the electrodes. The voltage (V') when a voltage of 500 V (V) was applied was measured, and the melt resistivity (ρ) was calculated from the following equation.

ρ (Ω ・ cm) = V ・ S ・ R / (I ・ V')
(However, in the formula, V: applied voltage (V), S: electrode area (cm ² ), R: resistor resistance (Ω), I: distance between electrodes (cm), V': measured voltage (V) Shows.).

(3) Gelation rate The polyethylene terephthalate resin composition was pulverized with a freeze pulverizer, and 0.5 g was weighed in a stainless beaker. After vacuum drying at 50 ° C. for 2 hours using a vacuum dryer, the oxygen concentration is adjusted to 1% with a mixed gas of air and nitrogen, and the mixed gas having an oxygen concentration of 1% is passed through a stainless steel beaker containing a sample through a pipe. The stainless beaker was immersed in an oil bath at 300 ° C., and a mixed gas of air and nitrogen having an oxygen concentration of 1% was circulated at a flow rate of 0.5 L / min and heat-treated for 6 hours. This was dissolved in 20 ml of orthochlorophenol (hereinafter OCP) at 160 ° C. for 1 hour and allowed to cool. This solution was filtered using a glass filter (3GP40 manufactured by Shibata Scientific Technology Co., Ltd.), and the glass filter was washed with dichloromethane. The glass filter was dried at 130 ° C. for 2 hours, the weight of the OCP insoluble matter (gel) remaining in the filter was calculated from the increment of the weight of the filter before and after the filtration, and the weight of the polyethylene terephthalate resin composition of the OCP insoluble matter (0). The weight fraction with respect to 5.5 g) was determined and used as the gelation rate.

(4) Solution haze The sample pellet of the polyethylene terephthalate resin composition was dissolved in 20 ml of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (60: 40 wt%) at 100 ° C. for 60 minutes by stirring to room temperature. After cooling, the mixture was transferred to a glass cell and measured using a haze meter.

(5) Microforeign matter Dissolve 1 g of sample pellets of polyethylene terephthalate resin composition in a mixed solvent of phenol / 1,2,2,2-tetrachloroethane (60: 40 wt%), filter with filter paper, and use a filter paper (60 times). ) Counted the number of black foreign substances (17 μm) on the filter paper surface. As for the fine foreign matter, those with less than 5 pieces were good, those with 5 or more and less than 10 pieces were accepted, and those with 10 or more pieces were rejected, and judged according to the above criteria.

(6) Electrostatically applied castability When an unstretched film was formed, the electrostatically applied castability was judged based on the following criteria, and the film that could be produced without problems was good (○) and adhered to the cast drum. Those with reduced properties but no problem in producing the film were evaluated as acceptable (Δ), and those having poor adhesion to the cast drum and having difficulty in producing the film were evaluated as rejected (×).

(7) Film defects (defects) during long-term extrusion
The polyethylene terephthalate resin composition is dried at 160 ° C. for 5 hours, then supplied to an extruder equipped with a T-die type base, and the extruded unstretched film is continuously extruded into a casting drum shape while rotating the casting drum from the base at 300 ° C. obtain. Observe the film surface for 1 hour after 10 hours and 11 hours, and if no streak-like defects were observed on the surface until 10 hours had passed, it was good (○), almost defective. Those who did not understand were accepted (Δ), and those with conspicuous defects were rejected (×).

(8) Total light transmittance (transparency) of the film
Based on JIS-K7361-1 (1997), the film after stretching was measured using a turbidity system NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The total light transmittance was judged according to the above criteria, with 89% or more being good, 85-89% or less being acceptable, and 85% or less being rejected.

(9) Coarse protrusions Two 10 cm square film measuring surfaces are overlapped with each other, and an applied voltage is applied to bring them into close contact with each other by electrostatic force, and the height is estimated from the interference fringes generated by the coarse protrusions on the film surface. To do. The interference fringes were 0.27 μm for the single ring and 0.54 μm for the double ring, and the number of coarse protrusions of 0.27 μm or more and less than 0.54 μm was measured. As for the coarse protrusions, those with less than 10 pieces were regarded as good (◯), those with less than 20 pieces were regarded as acceptable (Δ), and those with 20 or more pieces were regarded as rejected (x), and were judged according to the above criteria.

The polyethylene terephthalate resin compositions A, B, C and D were produced by the following methods.

(1) Production of Polyethylene terephthalate Resin Composition A An esterification reaction product, which is a reaction product of terephthalic acid and ethylene glycol, is stored in advance in a molten state at 255 ° C., and terephthalic acid and ethylene glycol are further stored in a molten state at 255 ° C. The esterification reaction product was obtained by making a slurry so that the molar ratio was 1.15, supplying a fixed amount while maintaining the temperature of the esterification reaction tank, and carrying out the esterification reaction while distilling water. The obtained esterification reaction product was transferred to a polymerization reaction tank.

An ethylene glycol solution containing triethylphosphonoacetate, an ethylene glycol solution containing potassium hydroxide, an ethylene glycol solution containing manganese acetate tetrahydrate, and an ethylene glycol solution containing antimony trioxide were added to the obtained polyethylene terephthalate resin composition. Then, 700 ppm as a manganese element, 45 ppm as a potassium element, and (Mn + K / 2) / P of manganese element, potassium element, and phosphorus element contents were added so as to be 9.0 and 220 ppm as an antimony element, and subsequently. The pressure inside the polymerization reaction tank was gradually reduced to 0.13 kPa or less in 35 minutes, and at the same time, the temperature was gradually raised to 278 ° C., and the polymerization reaction was carried out to the target intrinsic viscosity. After that, the polycondensation reaction tank is returned to normal pressure with nitrogen gas, discharged into cold water from the mouthpiece in a strand shape, pelletized into a columnar shape with an extrusion cutter, and pre-crystallized by a surface crystallization device to obtain a polyethylene terephthalate resin composition. Obtained. The resulting polyethylene terephthalate melt specific resistance of the resin composition is 0.65 × 10 ⁷ Ω · cm, gelation rate 10.0%, the solution haze was 2.2%.

(2) Production of Polyethylene terephthalate Resin Composition B In producing the polyethylene terephthalate resin composition in the same manner as described above, an ethylene glycol solution containing phosphoric acid and an ethylene glycol solution containing antimony trioxide can be obtained after the esterification reaction. To the polyethylene terephthalate resin composition, add 15 ppm as a phosphorus element and 110 ppm as an antimony element, gradually reduce the pressure to 0.13 kPa or less in 40 minutes, and carry out a polymerization reaction at 282 ° C. to carry out a polymerization reaction to the polyethylene terephthalate resin. Composition B was obtained. The resulting polyethylene terephthalate melt specific resistance of the resin composition B 260 × 10 ⁷ Ω · cm, gelation rate 2.6% solution haze was 0.5%.

(3) Production of Polyethylene terephthalate Resin Composition C In producing polyethylene terephthalate resin composition B in the same manner as described above, after the esterification reaction, an ethylene glycol solution containing phosphoric acid, an ethylene glycol solution containing potassium hydroxide, and manganese acetate An ethylene glycol solution containing tetrahydrate and an ethylene glycol solution containing antimony trioxide were added to the obtained polyethylene terephthalate resin composition at 30 ppm as a phosphorus element, 5 ppm as a potassium element, 45 ppm as a manganese element, and 110 ppm as an antimony element. The same method as in Example 1 was carried out except that the mixture was added so as to obtain polyethylene terephthalate resin composition C. The resulting polyethylene terephthalate melt specific resistance of the resin composition C is 25 × 10 ⁷ Ω · cm, gelation rate 0.9% solution haze was 0.6%.

(4) Production of Polyethylene terephthalate Resin Composition D In producing polyethylene terephthalate resin composition B in the same manner as described above, after the esterification reaction, an ethylene glycol solution containing phosphoric acid and an ethylene glycol solution containing magnesium acetate tetrahydrate The same as in Example 1 except that an ethylene glycol solution containing antimony trioxide was added to the obtained polyethylene terephthalate resin composition so as to have 30 ppm as a phosphorus element, 50 ppm as a magnesium element, and 110 ppm as an antimony element. This was carried out by the method to obtain a polyethylene terephthalate resin composition D. The resulting melt specific resistance of the polyethylene terephthalate resin composition D is 42 × 10 ⁷ Ω · cm, gelation rate 20.9% solution haze was 0.5%.

[Example 1]
The polyethylene terephthalate resin composition A and the polyethylene terephthalate resin composition B are blended in a film composition of 15 wt% of the polyethylene terephthalate resin composition A and 85 wt% of the polyethylene terephthalate resin assembly composition B with respect to the weight of the entire layer of the polyester film. Then, it was dried at 150 ° C. for 3 hours, supplied to an extruder, melt-extruded at 285 ° C., and cast on a cast drum at 20 ° C. to which electrostatically applied was applied to obtain an unstretched sheet. This unstretched sheet is stretched 3.1 times in the longitudinal direction by a stretching roll heated to 90 ° C., then stretched 3.7 times in the width direction at 120 ° C. by a tenter type stretching machine, and then heat-fixed at 200 ° C. And rolled it up on a roll. The electrostatic castability at the time of producing the film was good, and the defects, transparency and coarse protrusions of the obtained film were good.

[Examples 2 to 12]
The same method as in Example 1 was carried out except that the addition amounts of manganese acetate tetrahydrate, potassium hydroxide and triethylphosphonoacetate of the polyethylene terephthalate resin composition A were changed. The results are shown in Tables 1 and 2.

In Example 2, the amount of manganese acetate tetrahydrate added was changed so as to be 600 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element was obtained, and the defects, transparency and coarse protrusions of the obtained film were good. Met.

In Example 3, the amount of manganese acetate tetrahydrate added was changed so as to be 800 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element was obtained, and the defects, transparency and coarse protrusions of the obtained film were good. Met.

In Example 4, the melt resistivity increased by changing the addition amount of manganese acetate tetrahydrate so as to be 500 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element was obtained, and the static electricity during film molding was increased. Although the electrical applicability was reduced, it was within the usable range.

In Example 5, the gelation rate and the solution haze were increased by changing the addition amount of manganese acetate tetrahydrate so as to be 900 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element was obtained. Although the defects, transparency, and coarse protrusions of the film deteriorated, it was within the usable range.

In Example 6, the amount of potassium hydroxide added was changed so as to be 35 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element was obtained, and the defects, transparency and coarse protrusions of the obtained film were good. ..

In Example 7, the amount of potassium hydroxide added was changed so as to be 65 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element was obtained, and the defects, transparency and coarse protrusions of the obtained film were good. ..

In Example 8, the melt resistivity was increased by changing the amount of potassium hydroxide added so as to be 25 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element was obtained, and the electrostatic applicability during film molding was increased. Was observed, but it was within the usable range.

In Example 9, the solution haze was increased by changing the amount of potassium hydroxide added so as to be 80 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element was obtained, and the transparency and coarseness of the obtained film were increased. The protrusions deteriorated, but they were within the usable range.

In Example 10, by changing the addition amounts of manganese acetate tetrahydrate and potassium hydroxide so that the Mn / K of the obtained polyethylene terephthalate resin composition was 40.0, minute foreign substances increased, and the result was obtained. The coarse protrusions on the film were increased, but were within the usable range.

In Example 11, the melt resistivity was increased by changing the addition amount of triethylphosphonoacetate so that the obtained polyethylene terephthalate resin composition (Mn + K / 2) / P was 5.0, and film molding was performed. Although a decrease in electrostatic applicability was observed, it was within the usable range.

In Example 12, the gelation rate was increased by changing the addition amount of triethylphosphonoacetate so that the obtained polyethylene terephthalate resin composition (Mn + K / 2) / P was 18.0. Although the drawbacks of the film were increased, it was within the usable range.

[Examples 13 to 14]
The procedure was the same as in Example 1 except that magnesium acetate tetrahydrate was added to the polyethylene terephthalate resin composition A. The results are shown in Tables 1 and 2.

By adding magnesium acetate tetrahydrate to the polyethylene terephthalate resin composition from which the magnesium element can be obtained so as to be 0.3 ppm in Example 13 and 0.9 ppm in Example 14, the gelation rate is increased. The number of defects in the obtained film increased, but it was within the usable range.

[Examples 15 to 18]
The same method as in Example 1 was carried out except that the blending amounts of the polyethylene terephthalate resin composition A and the polyethylene terephthalate resin composition B were changed. The results are shown in Tables 1 and 2.

In Example 15, the blending amount was changed so that the manganese element was 210 ppm with respect to the weight in the entire film layer, and the defects, transparency, and coarse protrusions of the obtained film were good.

In Example 16, by changing the blending amount so that the manganese element was 230 ppm with respect to the weight in the entire film layer, gel generation during melting increased and the defects of the obtained film increased. It was within the usable range.

In Example 17, by changing the blending amount so that the M / P was 0.7, the electrostatic applicability at the time of film molding was lowered, but the obtained film was within the usable range. ..

In Example 18, by changing the blending amount so that the M / P was 4.0, the gel generation at the time of melting increased, but the obtained film was within the usable range.

[Example 19]
The same method as in Example 1 was carried out except that the phosphorus compound added to the polyethylene terephthalate resin composition A was changed from triethylphosphonoacetate to phosphoric acid. The results are shown in Tables 1 and 2. Due to the increase in minute foreign substances, the transparency and coarse protrusions of the obtained film deteriorated, but they were within the usable range.

[Examples 20 to 21]
Film molding was carried out in the same manner as in Example 1 except that the polyethylene terephthalate resin composition B was changed. The results are shown in Tables 1 and 2.

In Example 20, the polyethylene terephthalate resin composition B was changed to the polyethylene terephthalate resin composition C, and the defects, transparency, and coarse protrusions of the obtained film were good.

In Example 21, the polyethylene terephthalate resin composition B was changed to the polyethylene terephthalate resin composition D, and the defects, transparency, and coarse protrusions of the obtained film were good.

[Comparative Examples 1 to 8]
The same method as in Example 1 was carried out except that the addition amounts of manganese acetate tetrahydrate, potassium hydroxide and triethylphosphonoacetate of the polyethylene terephthalate resin composition A were changed. The results are shown in Tables 3 and 4.

In Comparative Example 1, by changing the addition amount of manganese acetate tetrahydrate so as to be 460 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element can be obtained, the melt resistivity is increased and the electrostatic application castability is increased. The product film could not be obtained due to poor application unevenness.

In Comparative Example 2, by changing the amount of manganese acetate tetrahydrate added so as to be 940 ppm with respect to the polyethylene terephthalate resin composition from which the manganese element can be obtained, minute foreign substances increased and the resulting film became coarse. The protrusion was defective.

In Comparative Example 3, by changing the addition amount of potassium hydroxide so as to be 17 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element can be obtained, the melt resistivity increases and the electrostatic application castability is poor. A lot of unevenness occurred and the product film could not be obtained.

In Comparative Example 4, by changing the amount of potassium hydroxide added so as to be 83 ppm with respect to the polyethylene terephthalate resin composition from which the potassium element can be obtained, minute foreign substances increased and the coarse protrusions of the obtained film were defective. Met.

In Comparative Example 5, the melt resistivity was increased by changing the addition amounts of manganese acetate tetrahydrate and potassium hydroxide so that the obtained polyethylene terephthalate resin composition had Mn / K of 5.0. The castability of electrostatic application was poor, and many uneven applications occurred, making it impossible to obtain a product film.

In Comparative Example 6, by changing the addition amounts of manganese acetate tetrahydrate and potassium hydroxide so that the Mn / K of the obtained polyethylene terephthalate resin composition was 46.5, minute foreign substances increased and coarseness was observed. An increase in protrusions was observed, which was defective.

In Comparative Example 7, the melt resistivity increased and the electrostatic charge was increased by changing the addition amount of triethylphosphonoacetate so that the obtained polyethylene terephthalate resin composition (Mn + K / 2) / P was 2.0. The applied castability was poor and many application irregularities occurred, making it impossible to obtain a product film.

In Comparative Example 8, the gelation rate was increased by changing the addition amount of triethylphosphonoacetate so that the obtained polyethylene terephthalate resin composition (Mn + K / 2) / P was 22.0, which was a drawback. There was an increase and it was poor.

[Comparative Example 9]
The procedure was the same as in Example 1 except that magnesium acetate tetrahydrate was added to the polyethylene terephthalate resin composition A. The results are shown in Tables 3 and 4. By adding magnesium acetate tetrahydrate so as to be 2 ppm with respect to the polyethylene terephthalate resin composition from which the magnesium element can be obtained, the gelation rate was increased and the defects were increased, which was a defect.

[Comparative Example 10]
In producing the polyethylene terephthalate resin composition A, after the esterification reaction, an ethylene glycol solution containing triethylphosphonoacetate, an ethylene glycol solution containing potassium hydroxide, an ethylene glycol solution containing magnesium acetate tetrahydrate, and antimony trioxide Except that the ethylene glycol solution containing the above is added to the obtained polyethylene terephthalate resin composition so as to be 320 ppm as the magnesium element, 50 ppm as the potassium element, 90 ppm as the phosphorus element, and 220 ppm as the antimony element. It was carried out in the same way. Since the gelation rate was as high as 30.0%, an increase in film defects was observed and the film was defective.

[Comparative Example 11]
In producing the polyethylene terephthalate resin composition A, it is produced in the same manner as in the polyethylene terephthalate resin composition C, and in film molding, it is produced in the same manner as in Example 1 except that only the polyethylene terephthalate resin composition A is blended. Carried out. The melt resistivity increased, the electrostatic application castability was poor, and many application irregularities occurred, so that a product film could not be obtained.

Claims (3)

It contains a manganese compound, a potassium compound and a phosphorus compound, the content (ppm) of each element satisfies the following (1) to (4), the content of the magnesium element in the polyethylene terephthalate resin is less than 1 ppm, and the melt ratio. polyethylene resistance 1.0 × 10 ⁷ Ω · cm or less, 300 ° C. oxygen concentration of 1 percent gelling rate when melted for 6 hours in a mixture of air and nitrogen is characterized in that 5% to 15% Telephthalate resin composition.
500 ≤ Mn ≤ 900 ... (1)
20 ≦ K ≦ 80 ・ ・ ・ (2)
6.25 ≤ Mn / K ≤ 45 ... (3)
3 ≦ (Mn + K / 2) / P ≦ 20 ・ ・ ・ (4)
The polyethylene terephthalate resin composition according to claim 1, wherein the solution haze is 2.5% or less. The polyester film comprising the polyethylene terephthalate resin composition according to claim 1 or 2, wherein the content of the manganese element contained in all the layers of the polyester film is 25 to 220 ppm, and the molar ratio of the metal element and the phosphorus element ( A polyester film having an M / P) of 1.5 to 4.0.