JP2015108038A - Polyester resin and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin capable of forming a film with good productivity and having less yellow coloring.SOLUTION: There is provided a polyester resin containing (1) a compound of at least one element selected from titanium group elements of the Group 4A on the periodic table, (2) at least one kind of bivalent metallic compound and (3) a phosphorus compound with amounts of the compound (1) of 2 mass.ppm to 10 mass.ppm in terms of titanium group elements of the Group 4A in the periodic table, the metallic compound (2) of 7 mass.ppm to 11 mass.ppm in terms of the metallic atom and the phosphorus compound (3) of the amount satisfying the formula 1 and each of the compound (1), the metallic compound (2) and the phosphorus compound (3) of the amount satisfying the formula 2 and having intrinsic viscosity ([η]) of 0.60 to 0.80 dl/g, where the intrinsic viscosity is a value measured at 30°C in a solution of a mixed solvent of phenol/tetrachloroethane (mass ratio 1/1), volume resistivity value at 285°C of 20×10Ω cm or less and color coordinate b value of 3.7 or less.

Description

  The present invention relates to a polyester resin, particularly a polyester resin suitable for film molding and a method for producing the same.

Conventionally, polyester resins such as polyethylene terephthalate resins are excellent in mechanical strength, chemical stability, gas barrier properties, fragrance retention, hygiene, etc., are relatively inexpensive, and are light in weight. Etc. have been widely used. Particularly in film applications, with recent high-speed molding, for example, deterioration of flatness at the time of film melt extrusion and reduction in productivity due to film breakage have become problems. In order to solve such problems, a polyester resin having a low volume specific resistance value and good adhesion is required for films.
Furthermore, recently, polyester films have been used for optical applications such as displays, and polyester films are required to be colorless and transparent and have little foreign matter.

As such a polyester resin having a small amount of foreign matter and a low volume resistivity, a resin produced by adding a predetermined amount of a titanium compound, a magnesium compound and a phosphorus compound is known. However (for example, patent document 1) However, it was a difficult point that yellow coloring of the obtained resin was remarkable.
On the other hand, Patent Document 2 discloses a resin produced by adding a predetermined amount of a titanium compound, a magnesium compound, and a phosphorus compound as a polyester resin having few foreign matters and excellent transparency. However, it was difficult that the obtained resin was markedly yellowed or had a high volume resistivity and poor film productivity.

JP 2005-89516 A Japanese Patent Laid-Open No. 2004-124067

  An object of the present invention is to provide a polyester resin capable of forming a film with high productivity and less yellowing.

And the gist of the present invention is as follows:
A polyester resin comprising a compound (1) of at least one element selected from titanium group elements of Group 4A of the periodic table, at least one divalent metal compound (2) and a phosphorus compound (3), The compound (1) is 2 mass ppm or more and 10 mass ppm or less in terms of titanium group metal atom of Group 4A of the periodic table, the metal compound (2) is 7 mass ppm or more and 11 mass ppm or less in terms of metal atom, phosphorus compound (3) Is contained in an amount satisfying the formula 1, and the compound (1), the metal compound (2) and the phosphorus compound (3) are each included in an amount satisfying the formula 2, and the intrinsic viscosity ([η]) is 0.60 to 0.80 dl. / G (where the intrinsic viscosity is a value measured at 30 ° C. in a mixed solvent solution of phenol / tetrachloroethane (mass ratio 1/1)), and the volume resistivity at 285 ° C. is 20 × 10 ⁷ Ω ・It is a polyester resin having a color coordinate b value of 3.7 or less.

Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
Formula 2: 0.7 ≦ M (1-P / M) / A <2
P: Amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
A: Amount of titanium group metal atom of Group 4A of the periodic table (mol / ton)
(However, mol / ton represents the number of moles of atoms per ton of polyester resin.) Another gist is a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of ethylene glycol. This is a method for producing the above-mentioned polyester resin, in which after the esterification reaction, melt polycondensation is subsequently carried out.

  The polyester resin of the present invention is capable of high speed molding of a film with little yellow coloring and less foreign matter. The method for producing a polyester resin of the present invention can be produced economically and stably, and is extremely useful industrially.

Next, the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiment of the present invention, and is not limited to these contents.
The polyester resin of the present invention is obtained by esterification or transesterification and polycondensation of a dicarboxylic acid component or a dicarboxylic acid ester derivative containing an aromatic dicarboxylic acid as a main component and a diol component.

The method for producing a polyester resin of the present invention is basically carried out by a conventionally known production method, that is, preparation of a raw material slurry, esterification and melt polycondensation.
Specific examples of the dicarboxylic acid component or dicarboxylic acid ester derivative used as a raw material include terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, and 4,4′-diphenyl. Dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid Aromatic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and the like, and succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid Fats such as acid and dodecadicarboxylic acid Like family dicarboxylic acid, the ester derivatives include alkyl esters having 1 to 6 carbon atoms.

  As the diol component used as the other raw material, specifically, ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, Aliphatic diols such as 2-ethyl-2-butyl-1,3-propanediol, polyethylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedi Alicyclic diols such as methylol, 1,4-cyclohexanedimethylol, 2,5-norbornane dimethylol, and xylylene glycol, 4,4′-dihydroxybiphenyl, 2, -Bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, etc. And 2,2-bis (4′-hydroxyphenyl) propane ethylene oxide adduct or propylene oxide adduct, and the like.

  Furthermore, as a copolymer component other than the diol component and the dicarboxylic acid component, for example, glycolic acid, p-hydroxybenzoic acid, hydroxycarboxylic acid such as p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acid, and stearyl alcohol, Monofunctional components such as heneicosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid , Gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, trifunctional or higher polyfunctional components such as sugar ester, etc., may be used alone or in combination.

Among them, in the present invention, a dicarboxylic acid component containing terephthalic acid and / or 2,6-naphthalenedicarboxylic acid as a main component, and ethylene glycol and / or diethylene glycol and / or cyclohexanediol and / or tetramethylene glycol as a main component. The polyester resin produced from a diol component is preferred, and more preferably the polyester resin produced from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component, and the effects of the present invention are most suitably exhibited. Is done.

  In the polyester resin of the present invention, terephthalic acid preferably accounts for 85 mol% or more of the dicarboxylic acid component, more preferably 90 mol% or more, and particularly preferably 95 mol% or more. Further, ethylene glycol preferably accounts for 85 mol% or more of the diol component, more preferably 90 mol% or more, and particularly preferably 95 mol% or more. When the proportion of terephthalic acid and ethylene glycol is less than the above range, the mechanical strength, heat resistance, etc. of the polyester resin tend to be inferior.

When the polyester resin of the present invention is produced, the ratio (molar ratio) of diol to dicarboxylic acid is usually in the range of 1.02 to 2.0, preferably 1.03 to 1.7.
In the polyester resin of the present invention, the compound (1) of at least one element composed of a Group 4A titanium group element in the periodic table is 2 mass ppm or more and 10 mass ppm or less in terms of a Group 4A titanium group metal atom, At least one divalent metal compound (2) in an amount of 7 mass ppm to 11 mass ppm in terms of metal atom and phosphorus compound (3) in an amount satisfying formula 1, as well as compound (1) and metal compound (2) And a phosphorus compound (3) in an amount satisfying the formula 2.

Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: amount of divalent metal atom (mol / ton)
Formula 2: 0.7 ≦ M (1-P / M) / A <2
P: Amount of phosphorus atom (mol / ton)
M: amount of divalent metal atom (mol / ton)
A: Amount of titanium group metal atom of Group 4A of the periodic table (mol / ton)
(However, mol / ton represents the number of moles of atoms per ton of polyester resin.)
Here, as a compound (1) selected from titanium group elements of Group 4A of the periodic table, that is, compounds of elements such as titanium, zirconium, hafnium, etc., oxides, hydroxides, alkoxides, acetates, carbonates, Examples include oxalates and halides.

Of these elemental compounds, titanium compounds are preferable, and specific examples of the titanium compounds include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, and tetra-n. -Titanium alkoxides such as butyl titanate tetramer, tetra-t-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, titanium oxide obtained by hydrolysis of titanium alkoxide, titanium alkoxide and silicon alkoxide or zirconium alkoxide Titanium-silicon or zirconium composite oxide obtained by hydrolysis of the mixture, titanium acetate, titanium oxalate, potassium titanium oxalate, sodium titanium oxalate, potassium titanate, sodium titanate, titanium Acid-aluminum hydroxide mixture, titanium chloride, titanium chloride-aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, hexafluoride Examples thereof include ammonium titanate and titanium acetylacetonate. Among these, titanium alkoxides such as tetra-n-propyl titanate, tetra-i-propyl titanate, and tetra-n-butyl titanate, titanium oxalate, and potassium potassium oxalate are preferable. -N-Butyl titanate is particularly preferred.

The at least one divalent metal compound (2) is preferably a compound of manganese, magnesium and calcium, and oxides, hydroxides, alkoxides, acetates, carbonates, oxalates and halides of these metals. Specific examples include magnesium oxide, magnesium hydroxide, magnesium alkoxide, magnesium acetate, magnesium carbonate, calcium oxide, calcium hydroxide, calcium acetate, calcium carbonate, manganese oxide, manganese hydroxide, manganese acetate, and the like. . Among these, a magnesium compound and a manganese compound are preferable, and a magnesium compound is particularly preferable. Therefore, it is preferable that the divalent metal compound is substantially composed only of the magnesium compound. Of the magnesium compounds, magnesium acetate is preferred.

  Specific examples of the phosphorus compound (3) include orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, Trivalent (triethylene glycol) phosphate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, pentavalent phosphorus such as phosphate ester such as triethylene glycol acid phosphate Compounds and phosphorous acid, hypophosphorous acid, and trimethyl phosphite, diethyl phosphite, triethyl phosphite, trisdodecyl Examples include phosphites such as sphite, trisnonyl decyl phosphite, ethyl diethyl phosphonoacetate, triphenyl phosphite, and trivalent phosphorus compounds such as metal salts such as lithium, sodium, and potassium. Phosphoric acid esters of these phosphorus compounds are preferred, and trimethyl phosphate and ethyl acid phosphate are particularly preferred.

  In the present invention, the compound (1) of at least one element selected from the Group 4A titanium group elements of the periodic table is present in the polyester resin in an amount of 2 to 10 ppm by mass in terms of their atoms. Is essential, and is preferably present at 3 mass ppm or more, more preferably at least 5 mass ppm. The upper limit is preferably 8 ppm by mass, particularly preferably 7 ppm by mass. If this amount is less than the above range, the polymerizability is remarkably deteriorated so that the desired polyester resin cannot be produced with good productivity, and if it exceeds the above range, the color tone of the polyester resin is extremely deteriorated and suitable for film production. It will not be.

Further, it is essential that at least one divalent metal compound (2) is present in the polyester resin in an amount of 7 mass ppm or more and 11 mass ppm or less in terms of metal atom, and preferably 8 mass ppm or more is present, and the upper limit is Preferably it is 11 mass ppm, Most preferably, it is 10 mass ppm.
If this amount is less than the above range, the volume resistivity value becomes high, resulting in deterioration of film productivity. If the amount exceeds the above range, the color tone of the polyester resin obtained is extremely yellow, and the color after melting is maintained. Gets worse.

Furthermore, it is essential to contain the phosphorus compound (3) in an amount that satisfies the following formula 1.
Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: amount of divalent metal atom (mol / ton)
The lower limit of P / M is preferably 0.48 or more, and the upper limit is preferably 0.63 or less, more preferably 0.60 or less.

If it is less than the said range, the thermal stability of the obtained polyester resin will worsen, and as a result, a color tone will deteriorate.
On the other hand, if the above range is exceeded, the polymerizability becomes poor and the volume resistivity of the obtained polyester resin becomes high, which makes it unsuitable for film production.
Further, it is essential that the compound (1), the metal compound (2), and the phosphorus compound (3) are contained in amounts that satisfy the formula 2.

Formula 2: 0.7 ≦ M (1-P / M) / A <2
P: Amount of phosphorus atom (mol / ton)
M: amount of divalent metal atom (mol / ton)
A: Amount of titanium group metal atom of Group 4A of the periodic table (mol / ton)
The lower limit of M (1-P / M) / A is preferably 1.0 or more, more preferably 1.1 or more. The upper limit is preferably 1.3 or less.

When the above range is exceeded, the polymerizability deteriorates. Moreover, if it is less than the range of the previous period, the malfunction that the color tone of a film deteriorates will arise.
The polyester resin of the present invention may contain components other than the above compounds (1), (2) and (3), and is particularly obtained by allowing a titanium group element compound to be present during the polycondensation reaction. There is no need to contain an antimony compound or a germanium compound.

  The antimony compound is reduced after the addition and precipitated in the polyester resin obtained as the antimony metal, and as a result, causes defects as foreign matters in the film obtained using the polyester resin. On the other hand, the use of a germanium compound is disadvantageous in terms of cost because the compound is expensive. Therefore, it is preferable that the polyester resin of the present invention does not substantially contain an antimony compound or a germanium compound.

  Examples of the method for producing a polyester resin according to the present invention include the case where a dicarboxylic acid component having terephthalic acid as a main component or an ester-forming derivative thereof and a diol component having ethylene glycol as a main component are used.

  The method for producing a polyester resin of the present invention comprises at least one compound (1) of at least one element selected from the group consisting of titanium group elements of Group 4A of the periodic table through an esterification reaction or a transesterification reaction. The divalent metal compound (2) and the phosphorus compound (3) are polycondensed in the presence of the polyester resin, but basically according to a conventional method for producing a polyester resin. That is, a dicarboxylic acid component mainly composed of the terephthalic acid or its ester-forming derivative and a diol component mainly composed of ethylene glycol are charged into a slurry preparation tank and mixed under stirring to form a raw slurry. The esterification reaction product or transesterification reaction product obtained after the esterification reaction in the esterification reaction tank under normal pressure to under pressure, under heating, or the ester exchange reaction in the presence of a transesterification catalyst The polyester low molecular weight product is transferred to a polycondensation tank, and in the presence of the compound, melt polycondensation is carried out under heating from normal pressure to gradually reduced pressure.

In the case of performing an ester exchange reaction using an ester-forming derivative of terephthalic acid as a dicarboxylic acid component, it is usually necessary to use an ester exchange catalyst such as a titanium compound, a magnesium compound, a calcium compound, a manganese compound, or a zinc compound. Also, it is necessary to use a relatively large amount of the transesterification catalyst. When these transesterification reaction catalysts are used in a large amount, the color tone of the polyester resin is deteriorated. Therefore, in the present invention, a method of producing the ester resin using terephthalic acid as a dicarboxylic acid component is preferable.

  The esterification reaction is carried out by using a multistage reaction apparatus in which a single esterification reaction tank or a plurality of esterification reaction tanks are connected in series, under reflux of ethylene glycol, and water generated in the reaction and excess ethylene. While the glycol is removed from the system, the esterification rate (the ratio of the esterified by reacting with the diol component out of all the carboxyl groups of the raw dicarboxylic acid component) is usually 90% or more, preferably 93% or more Done. Moreover, it is preferable that the number average molecular weight of the polyester low molecular weight body as an esterification reaction product obtained is 500-5,000.

As reaction conditions in the esterification reaction, in the case of a single esterification reaction tank, the temperature is usually about 240 to 280 ° C., and the relative pressure to atmospheric pressure is usually about 0 to 400 kPa (0 to 4 kg / cm ² G). The reaction time is about 1 to 10 hours under stirring. In the case of a plurality of esterification reaction tanks, the reaction temperature in the first stage esterification reaction tank is usually 240 to 270 ° C., preferably 245 to 265 ° C., and the relative pressure to atmospheric pressure is usually 5 to 300 kPa. (0.05 to 3 kg / cm ² G), preferably 10 to 200 kPa (0.1 to ² kg / cm ² G), and the reaction temperature in the final stage is usually 250 to 280 ° C., preferably 255 to 275 ° C. The relative pressure to atmospheric pressure is usually 0 to 150 kPa (0 to 1.5 kg / cm ² G), preferably 0 to 130 kPa (0 to 1.3 kg / cm ² G). In addition, it is preferable to make the increase amount equal in the esterification rate in each stage.

  In the esterification reaction, for example, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, quaternary hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and trimethylbenzylammonium hydroxide are used. By adding a small amount of a basic compound such as quaternary ammonium, lithium carbonate, sodium carbonate, potassium carbonate, sodium acetate, or the like, by-production of diethylene glycol from ethylene glycol can be suppressed.

  In the melt polycondensation, a single melt polycondensation tank or a plurality of melt polycondensation tanks connected in series, for example, a fully mixed reactor in which the first stage is equipped with a stirring blade, the second stage, and The third stage is carried out by distilling the produced ethylene glycol out of the system under reduced pressure using a multistage reactor comprising a horizontal plug flow reactor equipped with a stirring blade.

  As reaction conditions in the melt polycondensation, in the case of a single polycondensation tank, the temperature is usually about 250 to 290 ° C. The pressure is gradually reduced from normal pressure, and finally the absolute pressure is usually 1.3 to 0.013 kPa. (10 to 0.1 Torr) and a reaction time of about 1 to 20 hours with stirring. In the case of a plurality of polycondensation tanks, the reaction temperature in the first stage polycondensation tank is usually 250 to 290 ° C., preferably 260 to 280 ° C., and the absolute pressure is usually 65 to 1.3 kPa (500 to 10 Torr), preferably 26 to 2 kPa (200 to 15 Torr), the reaction temperature in the final stage is usually 265 to 300 ° C., preferably 270 to 295 ° C., and the absolute pressure is usually 1.3 to 0.013 kPa (10 to 10 Torr). 0.1 Torr), preferably 0.65 to 0.065 kPa (5 to 0.5 Torr). As reaction conditions in the intermediate stage, those intermediate conditions are selected. For example, in a three-stage reactor, the reaction temperature in the second stage is usually 265 to 295 ° C., preferably 270 to 285 ° C., and the absolute pressure is Usually, it is 6.5 to 0.13 kPa (50 to 1 Torr), preferably 4 to 0.26 kPa (30 to 2 Torr).

  At the time of polycondensation, the addition timing of the compound (1) and phosphorus compound (3) of at least one element selected from the group 4A titanium group elements of the periodic table to the reaction system is the slurry preparation step, esterification reaction Alternatively, any stage of the transesterification reaction process or an initial stage of the melt polycondensation process may be used, but the compound (1) is an esterification reaction or transesterification process, or a melt polycondensation process. The compound (1) is preferably added to the esterification reaction tank in the final stage in the multistage reaction apparatus or the ester in the transfer stage to the melt polycondensation process. It is preferably added to the esterification reaction or transesterification reaction product, and particularly preferably added to the esterification reaction or transesterification reaction product in the transfer stage to the melt polycondensation process. Arbitrariness. Moreover, it is preferable to add a phosphorus compound (3) to a slurry preparation process or esterification reaction or transesterification process, and it is especially preferable to add it to a slurry preparation process.

The metal compound (2) exhibits the effects of the present invention by being added to the transfer stage to the melt polycondensation step after the esterification rate of the esterification reaction or transesterification reaction product is 90% or more. I can do it. The metal compound (2) is preferably added before the compound (1).
The addition of compound (1), metal compound (2), and phosphorus compound (3) to the reaction system during polycondensation is preferably performed as a solution of alcohol such as ethylene glycol or water, and compound (1) As the ethylene glycol solution in the case of using a titanium compound as a titanium compound, the titanium atom concentration in the reaction system is 0.01 to 0.3 mass% and the water concentration is 0.1 to 1 mass%. From the viewpoint of improving the dispersibility of the compound and thereby the melt polycondensation property.

The polyester resin thus obtained by melt polymerization is usually melt-extruded into a strand shape, extracted from the reactor, and then cut and formed into chips.
In the production method of the present invention, inactive particles having an average particle diameter of 0.05 to 5.0 μm can be added at any time in order to obtain a resin suitable as a polyester resin for a film.

In the polyester resin of the present invention, the color coordinate b value of Hunter's color difference formula in the Lab color system described in Reference 1 of JIS Z8730 is preferably 3.7 or less as a color tone, and is 2.7 or less. Is more preferable, and 2.3 or less is particularly preferable. If the b value exceeds the above range, the color tone as a film molded product tends to turn yellow.
The color coordinate b value can be adjusted to 3.7 or less by adding the addition amounts of the compound (1), the metal compound (2), and the phosphorus compound (3) so as to satisfy the expressions 1 and 2. .

Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
Formula 2: 0.7 ≦ M (1-P / M) / A <2
P: Amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
A: Amount of titanium group metal atom of Group 4A of the periodic table (mol / ton)
(However, mol / ton represents the number of moles of atoms per ton of polyester resin.)
It is also possible to add a colorant to further improve the color tone.

As another adjustment method, the color coordinate b value can be adjusted by shortening the residence time of the polymerization tank or by lowering the temperature of the polymerization tank. However, in this case, in order to prevent a decrease in intrinsic viscosity, it is also necessary to consider lowering the pressure in the polycondensation tank or lowering the production rate.
The intrinsic viscosity ([η]) of the polyester resin of the present invention is 0.60 to 0.80 dl / g as a value measured at 30 ° C. with a mixed solvent solution of phenol / tetrachloroethane (mass ratio 1/1). It is preferable that it is 0.60 to 0.74 dl / g. If the intrinsic viscosity ([η]) is less than the above range, mechanical strength and transparency as a molded article such as a film or fiber tend to be insufficient, while if it exceeds the above range, film formability tends to be inferior. .

The polyester resin of the present invention has a volume resistivity value at 285 ° C. of preferably 20 × 10 ⁷ Ω · cm or less, more preferably 1 × 10 ^{6 to} 19 × 10 ⁷ Ω · cm, and more preferably 1 × It is particularly preferably 10 ⁷ to 18 × 10 ⁷ Ω · cm. When the volume resistivity value is out of the above range, the high-speed moldability of a film or the like tends to decrease. The volume resistivity value increases as the molar ratio of the phosphorus compound (3) to the metal compound (2) increases. The volume resistivity value increases as the binding reaction between the metal compound (2) and the phosphorus compound (3) proceeds. Therefore, as a method of adjusting the volume specific resistance value to 20 × 10 ⁷ Ω · cm or less, a method in which the addition amount of the metal compound (2) and the phosphorus compound (3) is within the range of the formula 1, or a metal compound Method of adding (2) and phosphorus compound (3) to separate reaction tanks, or adding metal compound (2) in the middle of transferring a polyester low molecular weight substance containing phosphorus compound (3) to a polycondensation tank Method, or method for shortening reaction time after adding metal compound (2) and phosphorus compound (3) when adding metal compound (2) and phosphorus compound (3) to a single reaction vessel Alternatively, a method such as a method of lowering the temperature at the time of adding the metal compound (2) and the phosphorus compound (3) can be mentioned.

  In particular, an esterification reaction product obtained by esterifying a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component in the presence of a phosphorus compound (3) The method of adding the metal compound (2) to the transfer pipe in the middle of transferring the polyester low molecular weight product to the polycondensation tank does not require operations to deteriorate the productivity of the resin, such as shortening the reaction time or lowering the temperature. In this respect, it is preferable.

Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
In addition, when P / M is less than the lower limit of the range of Formula 1, the color coordinate b value may be deteriorated, which is not preferable.

The polyester resin of this invention obtained by this has a volume specific resistance value, melt viscosity, and color tone preferable as a polyethylene terephthalate resin for films.
For the purpose of further increasing the degree of polymerization, the polyester resin is obtained by subjecting the granules after the melt polycondensation to a relative pressure with respect to atmospheric pressure in an inert gas atmosphere such as nitrogen, carbon dioxide, or argon. as usually 100kPa (1kg / ^cm 2 G) or less, preferably 20kPa0.2kg / ^cm 2 G) generally about 5-30 hours following pressure, or, as an absolute pressure usually 6.5～0.013KPa ( 50 to 0.1 Torr), preferably 1.3 to 0.065 kPa (10 to 0.5 Torr) under reduced pressure, usually about 1 to 20 hours, usually 190 to 230 ° C., preferably 195 to 225 ° C. Thus, solid phase polycondensation may be performed.

At that time, prior to solid-phase polycondensation, it is usually 120 to 200 ° C., preferably 130 to 190 ° C. for 1 minute to 4 in an inert gas atmosphere, or in a steam atmosphere or an inert gas atmosphere containing steam. It is preferable to crystallize the resin granule surface by heating for about an hour.
The polyester resin obtained by the production method of the present invention is, for example, formed into a sheet by extrusion molding, then formed into a tray or a container by thermoforming, or biaxially stretching the sheet to form a film, It is useful as a packaging material.

Molding of the polyester resin of the present invention into the molded body may be carried out as necessary by using an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, an antiblocking agent, an antifogging agent, a nucleating agent, and a plasticizer. Additives usually used for polyester resins, such as colorants, are added in accordance with conventional methods.
In particular, the polyester resin of the present invention is suitable as a film, in particular, a biaxially stretched film. As a molding method thereof, the polyester resin is melt-extruded into a film or a sheet, rapidly cooled by a cooling drum, or unstretched film or Sequential biaxial stretching method that stretches in the machine direction and then stretches in the transverse direction after preheating the unstretched film or sheet, or simultaneous biaxial stretching method that simultaneously biaxially stretches in the machine and transverse directions A conventionally well-known method is taken. The stretching ratio at that time is usually in the range of 2 to 6 times in both the longitudinal direction and the transverse direction, and after the biaxial stretching, if necessary, heat setting and / or heat relaxation. In addition, the thickness as a biaxially stretched film shall be about 1-300 micrometers normally.

In addition, in films, such as the said biaxially stretched film, it is preferable to add the lubricant which consists of an inorganic or organic particle | grain in order to prevent surface blocking. Examples of the inorganic particles include calcium carbonate, barium sulfate, alumina, silica, talc, titania, kaolin, mica, zeolite, etc., and surface-treated products thereof with silane coupling agents or titanate coupling agents. . Examples of the organic particles include acrylic resins, styrene resins, and crosslinked resins. The particle diameter of these lubricants is preferably in the range of 0.05 to 5.0 μm in average particle diameter. Moreover, the addition amount of these lubricants is 0.001-2.0 mass% normally, Preferably it is 0.05-1.0 mass%, More preferably, it is about 0.05-0.5 mass%.
The analysis method of the Example of this invention and a comparative example is demonstrated below.

<Metal atom content>
A resin sample of 2.5 g was ashed with hydrogen peroxide in the presence of sulfuric acid in a conventional manner, completely decomposed, and then made up to a constant volume of 50 ml with distilled water. A plasma emission spectrometer (ICP-AES manufactured by JOBIN YVON) "JY46P type") was quantified and converted to mass ppm in the polyester resin. When the resin contained a lubricant, the resin was dissolved in a solvent in advance, the undissolved lubricant was centrifuged, and then the supernatant was evaporated and dried.

<Intrinsic viscosity>
After 0.25 g of the pulverized resin sample was dissolved in a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1) at a concentration (c) of 1.0 g / dl at 110 ° C. for 30 minutes, an Ubbelohde type Using a capillary viscosity tube, the relative viscosity (η _rel ) with the stock solution was measured at 30 ° C., and the ratio between the specific viscosity (η _sp ) and the concentration (c) obtained from this relative viscosity (η _rel ) -1 (Η
_sp / c) was determined. Similarly, when the concentration (c) is 0.5 g / dl, 0.2 g / dl, and 0.1 g / dl, the respective ratios (η _sp / c) are obtained, and the concentration (c) is determined from these values. The ratio (η _sp / c) when extrapolated to 0 was determined as intrinsic viscosity [η] (dl / g).

<Volume specific resistance value>
15 g of resin sample is put into a test tube with a branch having an inner diameter of 20 mm and a length of 180 mm, and the inside of the tube is sufficiently purged with nitrogen. Then, the tube is immersed in an oil bath at 160 ° C. Then, the temperature of the oil bath was raised to 285 ° C. to melt the resin sample, and then the mixed air bubbles were removed by repeating nitrogen re-pressure and pressure reduction. Two stainless steel electrodes with an area of 1 cm 2 were inserted into the melt in parallel at an interval of 5 mm (non-opposite back surface covered with an insulator), and after the temperature was stabilized, an ohmmeter (manufactured by Hewlett-Packard Company “ MODEL HP4329A ") was applied with a DC voltage of 100 V, and the resistance value at that time was defined as a volume specific resistance value (Ω · cm).

<Color tone>
The resin sample is filled in a cylindrical powder colorimetric cell having an inner diameter of 36 mm and a depth of 15 mm, and described in Reference 1 of JIS Z8730 using a colorimetric color difference meter (“ZE2000” manufactured by Nippon Denshoku Industries Co., Ltd.). The color coordinate b value of Hunter's color difference formula in the Lab color system to be obtained was determined as a simple average value of values measured at four locations by rotating the measurement cell by 90 degrees by the reflection method.

<Electrostatic adhesion>
The resin sample was dried at 180 ° C., melt extruded at 290 ° C., and rapidly cooled and solidified on a rotary cooling drum maintained at a surface temperature of 40 ° C. to prepare an unstretched film. When winding this unstretched film, the film thickness unevenness was small by the electrostatic pinning method, and electrostatic adhesion was evaluated as follows from the speed at which the film could be stably wound.

○: Winding speed 35 m / min or more Δ: Winding speed 30 m / min or more and less than 35 m / min ×: Winding speed less than 30 m / min

<Film color tone>
An unstretched film is stretched 3.7 times in the longitudinal direction at 83 ° C., then stretched 3.9 times in the transverse direction at 110 ° C., and further heat-treated at 220 ° C. to give a biaxially stretched polyester film having a thickness of 38 μm. The color tone of the film was evaluated by visual observation as follows.

○: Yellow is inconspicuous and good △: Yellow is conspicuous ×: Very yellow Below, the present invention will be described in more detail with reference to examples. However, the present invention is limited to the following examples as long as the gist thereof is not exceeded. It is not a thing.

Example 1
A continuous polymerization apparatus comprising a slurry preparation tank, a two-stage esterification reaction tank connected in series to the slurry preparation tank, and a three-stage melt polycondensation tank connected in series to the second-stage esterification reaction tank was used. . While continuously supplying terephthalic acid and ethylene glycol at a mass ratio of 865: 485 to the slurry preparation tank, an ethylene glycol solution of ethyl acid phosphate has a phosphorus atom content of 6 with respect to the produced polyester resin. A slurry was prepared by continuously adding, stirring and mixing in an amount of 0.5 ppm by mass. The first stage esterification reaction tank in which the slurry is set at 260 ° C., a relative pressure of 50 kPa (0.5 kg / cm ² G), an average residence time of 4.5 hours under a nitrogen atmosphere, and a reaction product is present. The esterification reaction product in the first stage was then fed into a first stage set at 260 ° C., a relative pressure of 5 kPa (0.05 kg / cm ² G), and an average residence time of 1.2 hours under a nitrogen atmosphere. The mixture was continuously transferred to the second-stage esterification reaction tank and further esterified. Subsequently, when the esterification reaction product obtained above is transferred to a melt polycondensation tank, an ethylene glycol solution of magnesium acetate tetrahydrate is added to the esterification reaction product in the transfer pipe to produce polyester resin. In contrast, the magnesium atom was continuously added in an amount of 10.5 ppm by mass. Subsequently, when the esterification reaction product obtained above is transferred to the melt polycondensation tank, an ethylene glycol solution of tetra-n-butyl titanate is added to the esterification reaction product in the transfer pipe, and the generated polyester resin. The first stage melt polycondensation was set at 270 ° C. and an absolute pressure of 2.6 kPa (20 Torr) while continuously adding in an amount of 7.6 ppm by mass as titanium atoms. Tank, then second stage melt polycondensation tank set at 278 ° C., absolute pressure 0.5 kPa (4 Torr), then third stage set at 280 ° C., absolute pressure 0.3 kPa (2 Torr) Are continuously transferred to the melt polycondensation tank, and the residence time in each polycondensation tank is as follows. First stage 70 minutes, second stage 70 minutes, third stage 80 minutes, residence time 220 minutes in total Becomes way the melt polycondensation. A polyester resin was produced in the form of a strand from the outlet provided at the bottom of the third stage polycondensation tank, cooled with water, and then cut with a cutter to form chip-like granules. The evaluation results of the obtained polyester resin are shown in Table 1.

(Examples 2 and 3)
A polyester resin chip was produced in the same manner as in Example 1 except that the addition amounts of ethyl acid phosphate, magnesium acetate tetrahydrate and tetra-n-butyl titanate were changed as shown in Table 1, and evaluated in the same manner. The results are shown in Table 1.

(Comparative Examples 1, 3, 4, 5 and 6)
The addition amounts of ethyl acid phosphate, magnesium acetate tetrahydrate and tetra-n-butyl titanate were changed as shown in Table 1, and magnesium acetate tetrahydrate was provided in the second stage esterification reactor. A polyester resin chip was produced in the same manner as in Example 1 except that it was continuously added through the upper pipe and evaluated in the same manner. The results are shown in Table 1.

(Comparative Example 2)
A polyester resin chip was produced in the same manner as in Example 1 except that the addition amounts of ethyl acid phosphate, magnesium acetate tetrahydrate and tetra-n-butyl titanate were changed as shown in Table 1, and evaluated in the same manner. The results are shown in Table 1.

Claims (9)

A polyester resin comprising a compound (1) of at least one element selected from titanium group elements of Group 4A of the periodic table, at least one divalent metal compound (2) and a phosphorus compound (3), The compound (1) is 2 mass ppm or more and 10 mass ppm or less in terms of titanium group metal atom of Group 4A of the periodic table, the metal compound (2) is 7 mass ppm or more and 11 mass ppm or less in terms of metal atom, phosphorus compound (3) Is contained in an amount satisfying the formula 1, and the compound (1), the metal compound (2) and the phosphorus compound (3) are each included in an amount satisfying the formula 2, and the intrinsic viscosity ([η]) is 0.60 to 0.80 dl. / G (where the intrinsic viscosity is a value measured at 30 ° C. in a mixed solvent solution of phenol / tetrachloroethane (mass ratio 1/1)), and the volume resistivity at 285 ° C. is 20 × 10 ⁷ Ω ・A polyester resin having a color coordinate b value of 3.7 or less and not more than cm.
Formula 1: 0.47 ≦ P / M <0.7
P: amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
Formula 2: 0.7 ≦ M (1-P / M) / A <2
P: Amount of phosphorus atom (mol / ton)
M: Amount of divalent metal atom (mol / ton)
A: Amount of titanium group metal atom of Group 4A of the periodic table (mol / ton)
(However, mol / ton represents the number of moles of atoms per ton of polyester resin.)   The polyester resin according to claim 1, wherein the compound (1) is a titanium compound.   The polyester resin according to claim 1 or 2, wherein the metal compound (2) is a magnesium compound.   The polyester resin according to any one of claims 1 to 3, wherein the polyester resin comprises a dicarboxylic acid component and a diol component, wherein 95 mol% or more of the dicarboxylic acid component is terephthalic acid and 95 mol% or more of the diol component is ethylene glycol.   The polyester resin according to claim 1, which does not contain antimony and germanium.   The method for producing a polyester resin according to any one of claims 1 to 5, wherein a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component are subjected to an esterification reaction, followed by melt polycondensation.   After esterifying the dicarboxylic acid component containing terephthalic acid as the main component and the diol component containing ethylene glycol as the main component, the resulting polyester low molecular weight product as the esterification reaction product is transferred to the polycondensation tank. The method for producing a polyester resin according to claim 6, wherein a magnesium compound is added during the process, and then melt polycondensation is performed.   The polyester resin according to claim 1, which is for a film.   A polyester film obtained using the polyester resin according to claim 1.