JP6413581B2 - Polyester resin composition - Google Patents

Description

  The present invention relates to a polyester resin composition comprising polyester and polyetherimide as main components. More specifically, the present invention relates to a polyester resin composition having excellent film-forming properties, in which decomposition of polyester and polyetherimide is suppressed by containing iodine atoms in a specified amount range, heat resistance is improved, and gelation is suppressed. .

  Polyester is excellent in crystallinity, strength, chemical resistance, and transparency, and is used in various applications such as films, fibers, bottles, and extruded products. Among them, the film is used in various fields because of its excellent mechanical properties and economy, and its usefulness in magnetic recording is particularly well known. However, in recent years, magnetic recording media are required to have high density recording. In order to achieve higher density recording, increase the dimensional stability of the tape, use a thin magnetic layer and fine magnetic particles, and disperse the fine magnetic particles highly, thereby increasing the surface of the magnetic layer. It is effective to increase the smoothness of the recording medium, shorten the recording wavelength, and reduce the recording track.

  As a polyester film having high dimensional stability, a biaxially oriented polyester film made of polyethylene terephthalate and polyetherimide is known. However, in the coexistence of polyester and polyetherimide, the decomposition of the polyetherimide is caused by the generation of water and radicals generated by the decomposition of the polyester, and further the decomposition product of the polyetherimide accelerates the decomposition of the polyester, There is a problem that the heat resistance of the polyester is deteriorated, causing the generation of gel-like foreign matters, which causes defects on the film surface.

  As a method for suppressing gelation in a biaxially oriented polyester film made of polyester, for example, Patent Document 1 proposes a method of adding a halide to polyester.

  However, the above-described method is not sufficient for suppressing the degradation of polyetherimide and the gelation of polyester caused in the coexistence of polyester and polyetherimide. Therefore, when the recording track is made small, there is a problem that even a slight defect on the film causes data loss and damage, and further suppression of gelation is required.

JP 2010-265459 A

  The object of the present invention is to solve the above-mentioned conventional problems, to improve the heat resistance of polyester containing polyetherimide, and to provide a polyester resin composition excellent in film forming property, which suppresses the generation of foreign matters due to gelation. There is to do.

The object of the present invention as described above is a polyester resin composition comprising polyester and polyetherimide as main components , and contains 5 to 200 ppm of iodine atoms and 5 to 50 ppm of manganese atoms. This can be achieved by the composition.

  According to the present invention, in a polyester resin composition comprising polyester and polyetherimide as main components, by containing iodine atoms in a specified amount range, the heat resistance of the polyester resin composition is improved and foreign matter caused by gelation. Generation | occurrence | production can be suppressed and the film forming property excellent when it was set as the film can be obtained.

  The polyester in the present invention is not particularly limited, but ethylene terephthalate, ethylene-2,6-naphthalate, propylene terephthalate, butylene terephthalate, hexamethylene terephthalate, cyclohexanedimethylene terephthalate, propylene-2,6-naphthalate, butylene-2,6. -What has as a main component at least 1 type of structural unit chosen from the naphthalate, the hexamethylene-2,6- naphthalate, the cyclohexane dimethylene-2,6- naphthalate unit, etc. is preferable. Among these, polyesters having ethylene terephthalate as a main structural unit are particularly preferable because of excellent molding processability. Two or more kinds of polyesters may be mixed, or copolymerized polyesters may be used.

  When the polyester used in the present invention is polyethylene terephthalate, it is usually produced by one of the following processes. That is, (1) a process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by direct esterification reaction, and a high molecular weight polyester is obtained by subsequent polycondensation reaction, and (2) dimethyl terephthalate and ethylene glycol are used as raw materials. In this process, a low polymer is obtained by a transesterification reaction, and a high molecular weight polyester is obtained by a subsequent polycondensation reaction. Here, in the transesterification reaction, a commonly known transesterification catalyst which is a compound such as manganese, zinc, lithium, or titanium may be added.

  The polyetherimide in the present invention is a polymer containing an aliphatic, alicyclic or aromatic ether unit and a cyclic imide group as repeating units, and is not particularly limited as long as it is a polymer having melt moldability. Examples thereof include polyetherimides described in U.S. Pat. No. 4,141,927 and Japanese Patent No. 2622678, and polymers described in Japanese Patent No. 2,598,536 and JP-A-9-48852. As long as the effect of the present invention is not impaired, the main chain of polyetherimide contains a structural unit other than cyclic imide and ether units, for example, aromatic, aliphatic, alicyclic ester units, oxycarbonyl units, and the like. May be.

  Among them, 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride and m-phenylenediamine or p-phenylenediamine are preferred from the viewpoint of compatibility with polyester and melt moldability. And a polymer having a repeating unit represented by the following formula is preferred.

Or

  This polyetherimide is available from SABIC Innovative Plastics under the trade name “Ultem” (registered trademark), and is “Ultem 1000”, “Ultem 1010”, “Ultem 1040”, “Ultem 5000”, “Ultem 6000” and “Ultem XH6050”. "Series" and "Extreme XH" and "Extem UH" are well-known trademark names.

  In the present invention, it is preferable from the viewpoint of heat resistance that the weight fraction of polyetherimide in the polyester resin composition is 2 to 60% with respect to the polyester resin composition containing polyester and polyetherimide as main components. The method for producing the polyester composition of the present invention is not particularly limited, and polyetherimide may be added before the esterification or transesterification reaction of the polyester, or after the polymerization, the polyetherimide is added to the polymerization apparatus. However, a method in which polyester and polyetherimide are introduced into an extruder and melt kneaded is preferable in order to make the two types of polymers well compatible.

  The method for producing the polyester composition of the present invention is not particularly limited, and polyetherimide may be added before the esterification or transesterification reaction of the polyester, or after the polymerization, the polyetherimide is added to the polymerization apparatus. However, a method in which polyester and polyetherimide are introduced into an extruder and melt kneaded is preferable in order to make the two types of polymers well compatible.

The measuring method of the ratio of polyester and polyetherimide in the polyester resin composition is as follows.
That is, the polyester resin composition of the present invention is dissolved in hexafluoroisopropanol / chloroform as a solvent, and the NMR spectrum of 1H nucleus is measured. In the obtained spectrum, the peak area intensity of absorption specific to polyester and polyetherimide (for example, absorption of aromatic proton of terephthalic acid in the case of polyethylene terephthalate, absorption of proton of imide aromatic in polyetherimide) is obtained, The molar ratio of the blend is calculated from the ratio and the number of protons. Further, the weight ratio is calculated from the formula amount corresponding to the unit unit of each polymer. The measurement conditions are as follows.
Apparatus: BRUKER DRX-500 (Bruker)
Solvent: HFIP / deuterated chloroform Observation frequency: 499.8 MHz
Standard: TMS (0 ppm)
Measurement temperature: 30 ° C
Observation width: 10 KHz
Data point: 64K
acquisition time: 4.952 seconds pulse delay time: 3.048 seconds Integration count: 256 times.

  The polyester resin composition of the present invention needs to contain 5 to 200 ppm of iodine atoms. The preferred content is 80 to 170 ppm, more preferably 115 to 150 ppm. By containing an iodine atom in a specified amount range, it is possible to suppress the decomposition of the polyetherimide and to suppress the gelation of the polyester. If it is less than 5 ppm, the effect of inhibiting the decomposition of the polyetherimide by iodine becomes insufficient and causes gelation of the polyester. When it exceeds 200 ppm, the decomposition of the polyetherimide by iodine proceeds and causes gelation of the polyester. When a halide other than iodine is used, the gelation is not sufficiently suppressed.

  Although it does not specifically limit as a metal iodide compound added in order to make the polyester composition of this invention contain an iodine atom, From a viewpoint of suppressing decomposition | disassembly of polyetherimide, sodium iodide, potassium iodide, copper iodide Is preferred.

  In the present invention, as a method for containing iodine atoms in the polyester resin composition, from the viewpoint of uniformly dispersing in the polyester resin composition and the productivity of the polyester, a metal iodide compound is used at the time of kneading the polyester and polyetherimide. A method of kneading is preferred.

  The polyester resin composition of the present invention preferably contains a pentavalent phosphorus atom in an amount of more than 500 ppm and not more than 2000 ppm, more preferably 650 to 1300 ppm. By containing a pentavalent phosphorus atom in a specified amount range, it becomes possible to further suppress the degradation of the polyetherimide and the gelation of the polyester.

  Although it does not specifically limit as a phosphorus compound added in order to make the polyester composition of this invention contain a pentavalent phosphorus atom, From a viewpoint of suppressing decomposition | disassembly of polyetherimide, a triethyl phosphono acetate and a trimethyl phosphate are preferable.

  In the present invention, as a method for incorporating a pentavalent phosphorus atom into the polyester resin composition, from the viewpoint of uniformly dispersing in the polyester resin composition and the productivity of the polyester, pentavalent at the time of kneading the polyester and polyetherimide. A method of kneading these phosphorus compounds is preferred.

  The polyester resin composition of the present invention preferably contains substantially no alkaline earth metal atom. In addition, when it is below the detection limit by a fluorescent X-ray analyzer, it is assumed that it is not substantially contained. When the alkaline earth metal compound is not contained, it is possible to suppress the decomposition of the polyetherimide and the gelation of the polyester. In addition, the alkaline earth metal mentioned here refers to Be, Mg, Ca, Sr, Ba, and Ra belonging to Group IIA of the periodic table.

  The polyester resin composition of the present invention preferably contains 5 to 50 ppm of manganese atoms, more preferably 10 to 40 ppm, and still more preferably 15 to 30 ppm, from the viewpoint of suppressing the gelation of the polyester. By making the amount of manganese atoms within a specified range, it is possible to suppress the degradation of polyetherimide and the gelation of polyester. Although it does not specifically limit as a method to contain a manganese atom, It is preferable to add as a catalyst or an additive at the time of manufacture of polyester.

Next, although the manufacturing method of polyester of this invention is demonstrated in detail, it is not limited to this. Here, polyethylene terephthalate is used as the polyester.
First, bis-β-hydroxyethyl terephthalate (BHT) is obtained by esterifying terephthalic acid and ethylene glycol or by transesterifying dimethyl terephthalate and ethylene glycol. In the case of transesterification, manganese acetate tetrahydrate is added as a transesterification catalyst. Next, this BHT is transferred to a polymerization tank, and a conventionally known polymerization catalyst such as antimony, germanium, or titanium compound is added as a polymerization catalyst, and the temperature in the apparatus is slowly heated to 280 ° C., and the pressure is reduced from normal pressure to 133 Pa or less. . As the polymerization reaction proceeds, the viscosity of the reaction product increases. When the predetermined stirring torque is reached, the reaction is terminated, and the polyester is discharged from the polymerization apparatus into a water tank. The discharged polyester is quenched in a water tank and pelletized with a cutter.

  In order to increase the intrinsic viscosity of the obtained polyester, solid phase polymerization may be further performed. In the case of solid phase polymerization, the pelletized polyester is pre-crystallized at a temperature of 180 ° C. or less, and then solid phase polymerization is performed at 190 to 250 ° C. under reduced pressure of about 1 mmHg for 10 to 50 hours. As long as the effect of the present invention is not hindered, the polyester is known in the art using inert particles and various additives such as end-capping agents such as epoxy compounds, ultraviolet absorbers, antioxidants, antistatic agents, and surface active agents. An agent, a pigment, a fluorescent brightening agent, and the like may be appropriately contained as necessary.

  Next, the polyester pellets and the polyetherimide pellets are mixed at a predetermined ratio, vacuum-dried at 180 ° C. for 3 hours or more, and then supplied to a melt extruder heated to 270 ° C. to 300 ° C. At the same time, a metal iodide compound in an amount of 5 to 200 ppm as iodine element is supplied to the polyester resin composition while being metered with a measuring instrument, and melt-extruded to obtain a polyester resin composition. The residence time at this time is preferably 30 to 600 seconds, more preferably 60 to 300 seconds.

  Specific examples of the method for producing a magnetic recording medium film of the present invention will be described in detail, but the present invention is not limited to the following description.

  The obtained polyester resin composition pellets mainly composed of polyester and polyetherimide are vacuum-dried at 180 ° C. for 3 hours or more, and then in a nitrogen stream or under vacuum so that the intrinsic viscosity does not decrease. It is supplied to an extruder heated at 0 ° C., passed through a fiber sintered stainless metal filter, extruded from a slit-shaped die, and cooled while applying an electrostatic charge to a cast drum to obtain an unstretched film. At this time, the polyester resin composition of the present invention and polyethylene terephthalate may be mixed at a predetermined ratio, dried, and supplied to the extruder.

  The unstretched film can then be biaxially stretched and biaxially oriented. As the stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be adopted.

  In the case of stretching by sequential biaxial stretching, the obtained unstretched film is contacted on a roll group heated to (glass transition temperature Tg-30 ° C.) or more and (glass transition temperature Tg + 50 ° C.) or less of the polyester composition. The film was warmed and stretched 1.1 to 4.0 times in the longitudinal direction, and after cooling this, the end of the film was bitten into a tenter clip and the polyester composition (glass transition temperature Tg + 5 ° C. in the width direction). ) As described above, the polyester composition film is stretched 1.1 to 4.0 times in a temperature atmosphere of (glass transition temperature Tg + 50 ° C.) or less and biaxially oriented. When the biaxially oriented film after stretching is further heat-treated at a temperature in the range of Tg + 50 ° C. to Tg + 150 ° C., the dimensional stability is improved.

  The biaxially oriented film (support for magnetic recording medium) obtained as described above is slit, for example, into a width of 0.1 to 3 m, and conveyed at a speed of 20 to 300 m / min and a tension of 50 to 300 N / m. A magnetic paint and a non-magnetic paint are applied to one surface (A surface) with an extrusion coater. A magnetic paint is applied to the upper layer with a thickness of 0.1 to 0.3 μm, and a nonmagnetic paint is applied to the lower layer with a thickness of 0.5 to 1.5 μm. Thereafter, the support coated with the magnetic coating material and the nonmagnetic coating material is magnetically oriented and dried at a temperature of 80 to 130 ° C.

  Next, a back coat is applied to the opposite surface (B surface) with a thickness of 0.3 to 0.8 μm, and after calendar treatment, it is wound up. The calendering is performed using a small test calender (steel / nylon roll, 5 stages) at a temperature of 70 to 120 ° C. and a linear pressure of 0.5 to 5 kN / cm. Thereafter, the film is aged at 60 to 80 ° C. for 24 to 72 hours, slit to a width of 1/2 inch (1.27 cm), and a pancake is produced. Next, a specific length from this pancake is incorporated into a cassette to obtain a cassette tape type magnetic recording medium.

Examples of the composition of the magnetic paint include the following compositions.
Hereinafter, when “part” is simply described, it means “part by mass”.

[Magnetic layer forming coating solution]
Barium ferrite magnetic powder 100 parts [plate diameter: 20.5 nm, plate thickness: 7.6 nm, plate ratio: 2.7, Hc: 191 kA / m (≈2400 Oe) saturation magnetization: 44 Am2 / kg, BET specific surface area: 60 m2 / G]
12 parts polyurethane resin Mass average molecular weight 10,000
Sulfonic acid functional group 0.5 meq / g
α-Alumina HIT60 (Sumitomo Chemical Co., Ltd.) 8 parts Carbon black # 55 (Asahi Carbon Co., Ltd.) Particle size 0.015 μm 0.5 parts Stearic acid 0.5 parts Butyl stearate 2 parts Methyl ethyl ketone 180 parts Cyclohexanone 100 parts Magnetic layer forming coating solution]
Nonmagnetic powder α iron oxide 100 parts Average major axis length 0.09μm, specific surface area by BET method 50m2 / g
pH 7
DBP oil absorption 27-38ml / 100g
Surface treatment layer Al2O3 8% by mass
Carbon black 25 parts CONDUCTEX SC-U (manufactured by Colombian Carbon)
Vinyl chloride copolymer MR104 (manufactured by ZEON Corporation) 13 parts Polyurethane resin UR8200 (manufactured by Toyobo Co., Ltd.) 5 parts Phenylphosphonic acid 3.5 parts Butyl stearate

  Magnetic recording media include, for example, data recording applications, specifically computer data backup applications (for example, linear recording type recording media (linear magnetic recording media such as LTO4 and LTO5)) and digital image recording applications such as video. Can be suitably used.

The present invention will be described more specifically with reference to the following examples.
In addition, the measuring method of a physical property and the evaluation method of an effect were performed in accordance with the following method.

(1) Content of iodine atom in polyester resin composition A sample is weighed according to JISZ7302 and burned in a combustion tube, the generated gas is absorbed in the solution, and a part of the absorption liquid is ion using an ultraviolet absorption detector. Analysis was performed by chromatography ICA2000 (manufactured by Toa DDK Co., Ltd.).

(2) Content of metal atom of polyester resin composition Using a fluorescent X-ray elemental analyzer (manufactured by Horiba, Ltd., MESA-500W type), the fluorescent X-ray intensity for magnesium, calcium, phosphorus, and manganese is determined. It was determined from a calibration curve prepared in advance.

(3) Content of pentavalent phosphorus atom in polyester resin composition Using CMX-300 manufactured by Chemicals, solid ³¹ P-NMR measurement was performed at room temperature. As chemical shift standards, 85 wt% phosphoric acid aqueous solution (external standard 0.0 ppm) and (NH ₄ ) ₂ HPO ₄ (external standard 1.33 ppm) were used. About the obtained spectral peak, the total I ₃ of the peak value attributed to trivalent phosphorus (corresponding to the position of about 1100 to 160 ppm) and the peak value attributed to pentavalent phosphorus (about 50 ppm or less, from trivalent value) be used total I calculated ₅ as a ratio, the content P of the phosphorus atom as determined by the (2) in equivalent) to the low ppm, calculated content P ₅ of pentavalent phosphorus atom, by the following formula did. The spinning sideband was added to the integrated value of the main peak of each peak.

P ₅ = P × I ₅ / (I ₃ + I ₅ ).

(4) Gelation rate of polyester resin composition 1 g of the polyester resin composition was freeze-pulverized to form a powder having a diameter of 300 μm or less and vacuum-dried. The sample is heat treated in an oven at 300 ° C. for 2.5 hours in the atmosphere. This is dissolved in 50 ml of orthochlorophenol (OCP) by heating at a temperature of 80 to 150 ° C. for 0.5 hour. Subsequently, it is filtered through a Buchner type glass filter (maximum pore size 20-30 μm), washed and vacuum dried. The weight of the OCP insoluble matter remaining on the filter is calculated from the increase in the weight of the filter before and after filtration, and the weight fraction with respect to the weight of the OCP insoluble polyester resin composition (1 g) is obtained. did.

(5) Film forming property of polyester resin composition 99 parts by weight of a polyester resin composition and 1 part by weight of silica having an average particle size of 0.06 μm are mixed, and the mixture is melt-kneaded to prepare a silica-containing polyester resin composition. did. Next, 80 parts by weight of the polyester resin composition and 20 parts by weight of the silica-containing polyester resin composition are mixed, these mixtures are dried under reduced pressure at 180 ° C. for 3 hours, and supplied to an extruder heated to 300 ° C. Introduced into the base. Next, a melt of the polyester resin composition and the silica-containing polyester resin composition is extruded into a sheet from the inside of the T die die to form a molten single layer sheet, and the molten single layer sheet is charged into a cast drum having a surface temperature of 25 ° C. While being applied, the film was closely cooled and solidified to prepare an unstretched film, and the film forming property was judged according to the following criteria.
○: A film was successfully created.
(Triangle | delta): Although the adhesiveness fall to a cast drum was seen, there was no problem in preparation of a film.
X: Adhesion to the cast drum was poor, making it difficult to produce a film.

Example 1
An esterification reaction product (low polymer) of 86 parts by weight of terephthalic acid and 39 parts by weight of ethylene glycol was melted at 240 ° C. in an ester exchange reaction tank, and 86 parts by weight of terephthalic acid and 39 parts by weight of ethylene glycol were added thereto. The esterification reaction is continued while stirring at 250 ° C., and a reaction product corresponding to 86 parts by weight of terephthalic acid is converted from the esterification reaction product in which the water distillation amount reaches 97% or more of the theoretical distillation amount. It moved to. Subsequently, 0.03 parts by weight of antimony trioxide, 30 ppm of triethylphosphonoacetate as a phosphorus atomic weight with respect to polyester, 6 ppm of lithium acetate dihydrate as a lithium atomic weight with respect to polyester, and manganese acetate tetrahydrate as polyester Was added to the polycondensation reaction tank to which the esterification reaction product was transferred. Thereafter, while stirring the esterification reaction product, the reaction system was gradually heated from 250 ° C. to 280 ° C., and the pressure was reduced to 0.1 kPa. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen to return to normal pressure, the polycondensation reaction was stopped, discharged into cold water in the form of a strand, and immediately cut to obtain a polyester.

Next, 50 parts by weight of polyester pellets obtained by the above method, 50 parts by weight of polyetherimide (“ULTEM 1010-1000” (registered trademark) manufactured by SABIC Innovative Plastics), and the atomic weight of iodine with respect to the polyester resin composition As an example, potassium iodide in an amount of 140 ppm and triethylphosphonoacetate in an amount of 750 ppm as the amount of phosphorus atoms with respect to the polyester resin composition were rotated in the same direction. And kneaded and discharged under conditions of an extrusion temperature of 300 ° C., a shear rate of 150 seconds-1 and a residence time of 3.5 minutes, cooled with water, pelletized, and molded into pellets.
Table 1 shows the composition, production conditions and evaluation results of the obtained polyester resin composition. The polyester resin composition of the present invention had a gelation rate as low as 0.1% and was good.

Examples 2 and 3
A polyester resin composition was obtained in the same manner as in Example 1 except that the ratio of polyester and polyetherimide was changed. The results are shown in Table 1. In Example 2, the gelation rate of the polyester resin composition was good. In Example 3, since the ratio of polyester in the polyester resin composition was reduced, the contents of alkali metal and manganese metal were reduced. For this reason, the adhesion to the cast drum at the time of film formation was slightly reduced, but at a level with no problem, and the gelation rate and film forming property of the polyester resin composition were good.

Examples 4 and 5
A polyester resin composition was obtained in the same manner as in Example 1 except that the content of iodine atoms was changed. The results are shown in Table 1. In Example 4, an increase in gelation rate was observed due to the decrease in the amount of iodine atoms, but the level was satisfactory. Moreover, in Example 5, although the gelation rate increased by increasing the amount of iodine atoms, it was at a level with no problem.

Example 6
In the polycondensation reaction of polyester, when the predetermined stirring torque is reached, potassium iodide is added to the polycondensation reaction tank, and after stirring for 5 minutes, the reaction system is purged with nitrogen to return to normal pressure and the polycondensation reaction is stopped. Then, a polyester resin composition was obtained in the same manner as in Example 1 except that the polyester was obtained by discharging into cold water in a strand and immediately cutting. The results are shown in Table 1. In Example 6, since the time when potassium iodide was added was changed, the dispersion became insufficient and a slight increase in the gelation rate was observed.

Example 7
A polyester resin composition was obtained in the same manner as in Example 1 except that the pentavalent phosphorus compound kneaded during kneading was changed to trimethyl phosphate. The results are shown in Table 1. In Example 7, the gelation rate of the polyester resin composition was good.

Examples 8-10
A polyester resin composition was obtained in the same manner as in Example 1 except that the content of the pentavalent phosphorus atom was changed. The results are shown in Table 1. In Examples 8 and 9, the gelation rate of the polyester resin composition was good. In Example 10, the decrease in adhesion to the cast drum at the time of film formation was slightly caused by increasing the amount of phosphorus atoms, but there was no problem. The gelation rate and film forming property of the polyester resin composition Was good.

Example 11
A polyester resin composition was obtained in the same manner as in Example 1 except that the pentavalent phosphorus compound kneaded during kneading was not added. The results are shown in Table 1. In Example 11, since no phosphorus atom was added during kneading, an increase in the gelation rate was slightly observed, but it was at a level with no problem.

Example 12
In the polycondensation reaction of polyester, after the transition to the polycondensation reaction tank, magnesium acetate tetrahydrate was weighed so as to be 60 ppm as the magnesium atomic weight with respect to the polyester, and the polycondensation reaction tank in which the esterification reaction product was transferred A polyester was obtained in the same manner as in Example 1 except that the polyester was added. Next, 50 parts by weight of the polyester pellets and 50 parts by weight of the polyetherimide were added to the polyester resin composition in the same manner as in Example 1 using the same-direction rotating twin-screw kneading extruder (Toshiba Machine Co., Ltd. TEM-35B). Thus, a polyester resin composition containing 30 ppm as a magnesium atomic weight was obtained. The results are shown in Table 1. In Example 12, the addition of magnesium acetate resulted in an increase in the gelation rate, but it was at a satisfactory level.

Examples 13-16
A polyester resin composition was obtained in the same manner as in Example 1 except that the manganese atom content was changed. The results are shown in Table 1. In Examples 13 and 15, the gelation rate of the polyester resin composition was good. In Example 14, although the gelation rate increased slightly by increasing the manganese atom content, it was at a satisfactory level. In Example 16, an increase in gelation rate was observed by not adding manganese atoms, but this was a satisfactory level.

Comparative Example 1
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition of the metal iodide compound was not performed. The results are shown in Table 1. In Comparative Example 1, since there was no iodine content, the gelation rate increased and was poor.

Comparative Example 2
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition of the metal iodide compound was changed to the addition of potassium bromide as the metal bromide compound. The results are shown in Table 1. In Comparative Example 2, the effect of suppressing gelation by bromine atoms was not obtained, and an increase in the gelation rate was observed, which was poor.

Comparative Examples 3 and 4
A polyester resin composition was obtained in the same manner as in Example 1 except that the content of iodine atoms was changed. The results are shown in Table 1. Since the comparative example 3 was less than 5 ppm of iodine atom content, the gelation rate increased and was poor. Since the content of iodine atoms exceeded 200 ppm in Comparative Example 4, the gelation rate increased and was poor.

Claims (4)

A polyester resin composition comprising polyester and polyetherimide as main components, containing 5 to 200 ppm of iodine atoms and 5 to 50 ppm of manganese atoms .   The polyester resin composition according to claim 1, wherein the polyester resin composition contains an amount of more than 500 ppm and not more than 2000 ppm as pentavalent phosphorus atoms. The polyester resin composition according to claim 1 or 2, wherein the polyester resin composition contains substantially no alkaline earth metal atom. The film for magnetic recording media using the polyester resin composition of any one of Claims 1-3 .