JP2000256452A - Method for producing polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyester resin which does not contain an antimony compound, is excellent in polymerizability, and is excellent in color tone and heat stability of the obtained resin. SOLUTION: In producing a polyester resin by polycondensing a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid and a diol component mainly composed of ethylene glycol through an esterification reaction, the theory of the polyester resin is considered. Phosphorus atom (P) is 0.1 per ton of yield.
02-4 mol, titanium atom (Ti) 0.02-0.2
Mol, cobalt atom (Co) is 0.05 to 2 mol, and divalent metal atom (M) other than cobalt is 0.04 to 5 mol.
A method for producing a polyester resin which is polycondensed in the presence of a molar amount of a phosphorus compound, a titanium compound, a cobalt compound, and a divalent metal compound other than cobalt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester resin containing no antimony compound, which is commonly used as a polycondensation catalyst. The present invention relates to a method for producing a polyester resin having excellent properties.

[0002]

2. Description of the Related Art Conventionally, polyester resins represented by polyethylene terephthalate resins have attracted attention in terms of excellent transparency, gas barrier properties, safety and health, and the like, in addition to excellent mechanical properties and chemical properties. Injection molded preforms as stretch blow molded bottles, or extruded sheets as thermoformed trays or cups,
Alternatively, as a film or the like obtained by biaxially stretching the sheet, remarkable growth has been exhibited, particularly in the field of food packaging.

[0003] These polyester resins have hitherto been produced mainly using an antimony compound as a polycondensation catalyst. However, when the produced polyester resin is molded and used as a food and drink container, for example, it is contained in the resin. There is a concern that the remaining antimony is eluted from the container at a high temperature and slightly migrates to the content of food and drink, and the replacement thereof is strongly desired.

On the other hand, as a method for producing a polyester resin containing no antimony compound, many methods using a titanium compound as a polycondensation catalyst have been proposed, but the resulting resin has a yellowish color tone, There has been a problem that the color tone after heating is large and the thermal stability is poor.

Further, in order to solve the above problems, for example, Japanese Patent Application Laid-Open No. 8-73581 discloses "esterification of aromatic dicarboxylic acid with aliphatic diol or aliphatic diol of aromatic dicarboxylic acid lower aliphatic ester". For the production of heat-stable, antimony-free, achromatic polyesters by transesterification and subsequent polycondensation, wherein the possible transesterification is based on Catalyst 20-120
ppm, and then, after the esterification or transesterification is completed, phosphoric acid, phosphorous acid and / or phosphonic acid or their derivatives are added to the esterification or transesterification batches as complexing agents, An amount of up to 100% of the equivalent to the transesterification catalyst used and up to 99% of the equivalent to the cobalt used is added, up to 80 ppm of cobalt in the form of a cobalt compound is added to the batch and the polycondensation adds antimony. Titanium 1 added in the form of a titanium compound without any
Performed in the presence of -10 ppm ".

However, according to the study of the present inventors, this production method has an insufficient polymerization rate,
It was found that the color tone of the obtained resin was bluish, and that the change in color tone after heating was little improved and the thermal stability was still insufficient.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and does not contain an antimony compound, is excellent in polymerizability, and has excellent color tone and thermal stability of the obtained resin. An object of the present invention is to provide an excellent method for producing a polyester resin.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. That is, the present invention provides a dicarboxylic acid component containing an aromatic dicarboxylic acid as a main component and ethylene glycol as a main component. In a polyester resin produced by polycondensation with a diol component through an esterification reaction, 0.02 to 4 mol of phosphorus atoms (P) and titanium atoms (Ti ) Is 0.02 to 0.2 mol, cobalt atom (Co) is 0.05 to 2 mol, and 2 other than cobalt
Method for producing a polyester resin which is polycondensed in the presence of a phosphorus compound, a titanium compound, a cobalt compound, and a divalent metal compound other than cobalt in an amount such that the valence metal atom (M) is 0.04 to 5 mol. , And the gist.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the process for producing a polyester resin according to the present invention, a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid and a diol component mainly composed of ethylene glycol are polycondensed through an esterification reaction. This produces a polyester resin.

Here, the aromatic dicarboxylic acid accounts for 50 mol% or more of the total dicarboxylic acid component, and
It preferably accounts for at least mol%, more preferably at least 90%, particularly preferably at least 95%. Ethylene glycol is 50% of all diol components.
It accounts for at least 80 mol%, preferably at least 80 mol%, more preferably at least 90%, particularly preferably at least 95%.

In the present invention, specific examples of the aromatic dicarboxylic acid 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'-diphenyl sulfone dicarboxylic acid, 2,6-naphthalene Examples thereof include dicarboxylic acids, among which terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable, and terephthalic acid is particularly preferable.

The dicarboxylic acid components other than the aromatic dicarboxylic acids include, for example, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and malonic acid, succinic acid, glutaric acid, adipic acid. And aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid and dodecadicarboxylic acid.

The diol components other than ethylene glycol include, for example, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl -2-butyl-1,3-
Aliphatic diols such as propanediol, diethylene glycol, polyethylene glycol, and polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, and 1,4-cyclohexanedimethylol; An alicyclic diol, and xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2-bis (4′-β-hydroxyethoxyphenyl) propane,
Bis (4-hydroxyphenyl) sulfone, bis (4-
Aromatic diols such as β-hydroxyethoxyphenyl) sulfonic acid, and ethylene oxide adducts or propylene oxide adducts of 2,2-bis (4′-hydroxyphenyl) propane are listed. , 4-Cyclohexane dimethylol is preferred. In addition, diethylene glycol is generally produced as a by-product during the production of polyester, but can also be used as a raw material for a copolymer component. In this case, the total amount is preferably 5 mol% or less.

Further, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t- Monofunctional components such as butylbenzoic acid and benzoylbenzoic acid, and trifunctional or higher functionalities such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol and pentaerythritol. One or two or more functional components may be used as the copolymer component.

The method for producing the polyester resin of the present invention comprises the steps of:
A polyester resin is produced by polycondensing a dicarboxylic acid component containing the aromatic dicarboxylic acid as a main component and a diol component containing ethylene glycol as a main component through an esterification reaction. And a conventional method for producing a polyester resin. That is, the dicarboxylic acid component containing the aromatic dicarboxylic acid as a main component and the diol component containing ethylene glycol as a main component are usually mixed in an esterification reaction tank in the presence of an esterification catalyst, if necessary, in the range of 240 to 280. ° C, preferably 250-27
0 ° C., usually 0-3 kg / cm ² G, preferably 0
Under a pressure of ~ ² kg / cm < ² > G, the esterification reaction is carried out for 1 to 10 hours with stirring, and the resulting polyester low molecular weight product as the esterification reaction product is transferred to a polycondensation tank,
In the presence of the polycondensation catalyst, the temperature is usually 260 to 290 ° C., preferably 265 to 285 ° C., and usually 0.1 to 10 mmHg, preferably 0.5 to 0.5 mmHg, gradually reduced from normal pressure to normal pressure.
It is performed by melt polycondensation for 1 to 20 hours under stirring under reduced pressure of ５5 mmHg, and these are performed continuously or batchwise.

In general, the resin obtained by melt polycondensation is drawn out in a strand form from a discharge port provided at the bottom of the polycondensation tank, and cut with a cutter with or after cooling with water, and then pelletized into a pellet form. Although it is a granular material such as a chip, the granular material after the melt polycondensation is usually
Under an inert gas atmosphere such as nitrogen, carbon dioxide, and argon,
Or, in a steam atmosphere, or in a steam-containing inert gas atmosphere, usually at 60 to 180 ° C, preferably 150 to 17 ° C.
After being heated at a temperature of 0 ° C. to crystallize the surface of the resin granule, under an inert gas atmosphere, and / or 0.1 to 10 m
Under a reduced pressure of about mHg, usually just below the adhesive temperature of the resin to 8
At a temperature lower than 0 ° C., preferably at a temperature lower by 10 to 60 ° C. than the adhesive temperature, it is preferable to carry out a heat treatment for a period of usually not more than 50 hours to carry out solid-phase polycondensation while allowing the particles to flow so as not to adhere to each other. By this solid-phase polycondensation, the degree of polymerization can be further increased, and acetaldehyde, low molecular oligomer, and the like, which are reaction by-products, can also be reduced.

Further, the resin obtained by the above-mentioned melt polycondensation or solid phase polycondensation is usually immersed in water at 40 ° C. or more for 10 minutes or more in order to deactivate the polycondensation catalyst. A treatment such as a water treatment or a steam treatment in which the substrate is brought into contact with steam or a steam-containing gas at 60 ° C. or higher for 30 minutes or more may be performed.

The method for producing the polyester resin of the present invention comprises:
In the polycondensation, the phosphorus atom (P) is 0.02 to 4 mol, the titanium atom (Ti) is 0.02 to 0.2 mol, and the cobalt atom (C
o) in an amount of 0.05 to 2 mol, and an amount of a divalent metal atom (M) other than cobalt in a content of 0.04 to 5 mol, a phosphorus compound, a titanium compound, a cobalt compound, and a compound other than cobalt. Polycondensation in the presence of a divalent metal compound is essential.

When the amount of the phosphorus compound is less than the above range as the phosphorus atom (P), the resulting polyester resin has poor color tone and thermal stability, while when the amount exceeds the above range, the polymerizability is poor. In addition, the amount of the titanium compound is determined to be titanium atom (Ti).
If it is less than the above range, the polymerizability will be poor, while if it is more than the above range, the resulting polyester resin will have poor color tone and thermal stability. If the amount of the cobalt compound is less than the above range as a cobalt atom (Co), the polymerizability is poor, while if the amount exceeds the above range, the color tone and thermal stability of the obtained polyester resin are poor. Further, by setting the amount of the divalent metal compound other than cobalt as the metal atom (M) within the above range, it is possible to improve the polymerizability while suppressing a decrease in color tone and thermal stability of the obtained polyester resin. is there.

The number of moles of each of these atoms is such that the phosphorus atom (P) is 0.2 per ton of the theoretical yield of the polyester resin.
４4 mol, 0.04 to 0.16 mol of titanium atom (Ti), 0.1 to 1 mol of cobalt atom (Co), and 0.4 to 5 mol of divalent metal atom (M) other than cobalt. It is preferably the amount of each compound that results in a molar content.

The amount of each compound satisfies the above range as phosphorus atom (P), titanium atom (Ti), cobalt atom (Co) and divalent metal atom (M) other than cobalt. Further, the molar ratio (Ti / P) of the titanium atom (Ti) to the phosphorus atom (P) is 0.05-1 and the molar ratio (Co / P) of the cobalt atom (Co) is 0.1-1. , And the molar ratio of divalent metal atoms (M) other than cobalt (M /
P) is preferably 0.1 to 10, Ti / P is 0.1 to 0.4, Co / P is 0.2 to 0.95, and
M / P is more preferably 1 to 8, and the molar ratio of the sum of the cobalt atom (Co) and the divalent metal atom (M) other than cobalt to the titanium atom (Ti) [(Co +
M) / Ti] is preferably from 5 to 50.

Here, as the phosphorus compound, specifically,
For example, orthophosphoric acid, polyphosphoric acid, and their esters, such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, etc., methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, Pentavalent phosphorus compounds such as butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, and other acidic esters thereof, phosphorous acid, hypophosphorous acid, and diethyl phosphite, trisdodecyl phosphite, trisnonyl decyl phosphate Phyto, triphenyl phosphite, etc., their esters or their metal salts such as lithium, sodium, potassium, etc.
Phosphorus compounds and the like, among which orthophosphoric acid and phosphorous acid are preferable.

Further, as the titanium compound, specifically,
For example, tetrapropyl titanate, tetrabutyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, titanium oxalate, titanium potassium oxalate, titanium sodium oxalate, potassium titanate, sodium titanate, sodium titanate-aluminum titanate Mixture, titanium chloride, titanium chloride-aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, titanium acetyl Acetonate and the like, among which
Tetrapropyl titanate, tetrabutyl titanate,
Titanium oxalate, potassium potassium oxalate, a mixture of titanic acid and aluminum hydroxide, a mixture of titanium chloride and aluminum chloride, and cobalt hexafluorotitanate are preferred.

Specific examples of the cobalt compound include cobalt formate, cobalt acetate, cobalt stearate, cobalt oxalate, cobalt carbonate, cobalt bromide, and cobalt acetylacetonate. Cobalt formate and cobalt acetate are preferred.

Examples of the divalent metal compound other than cobalt include, for example, magnesium, calcium,
Oxides, hydroxides, alkoxides, halides such as zirconium, hafnium, chromium, molybdenum, tungsten, manganese, iron, nickel, gold, silver, copper, zinc, boron, aluminum, silicon, germanium, tin, lanthanum, and cerium , Carbonate, carboxylate, phosphate and the like, and these may be used in combination of two or more kinds thereof. Among them, magnesium oxide, magnesium hydroxide, magnesium alkoxide, magnesium carbonate, magnesium acetate, hydrogen phosphate Magnesium compounds such as magnesium, calcium compounds such as calcium oxide, calcium hydroxide, calcium carbonate and calcium acetate, manganese compounds such as manganese oxide, manganese hydroxide and manganese acetate are preferred, and magnesium compounds and manganese compounds are particularly preferred.

In the method for producing a polyester resin of the present invention, the phosphorus compound, the titanium compound, the cobalt compound, and the divalent metal compound other than cobalt are added to the polymerization system by using the aromatic dicarboxylic acid as a raw material. When preparing a slurry of ethylene glycol, and other dicarboxylic acid components and diol components used as necessary,
Any step of the esterification step or any of the initial stages of the melt polycondensation step may be performed, but the order of addition thereof is as follows: phosphorus compound, divalent metal compound other than cobalt, cobalt compound, titanium compound The order is preferably as follows.

Further, the method for producing a polyester resin of the present invention includes a method of preparing the above-mentioned phosphorus compound, titanium compound, cobalt compound,
And a metal compound other than the above-mentioned divalent metal compound other than cobalt, and specific examples of the metal element in that case include lithium, sodium, potassium, rubidium, and cesium.

The polyester resin obtained by the production method of the present invention has an intrinsic viscosity after melt polycondensation before solid phase polycondensation, which is phenol / tetrachloroethane (weight ratio 1/1).
Is preferably 0.4 to 0.9 dl / g as a value measured at 30 ° C. in a mixed solvent solution, and the intrinsic viscosity after solid-phase polycondensation is preferably 0.5 to 1. 5dl
/ G.

For the color tone, refer to JIS Z8730 Reference 1.
The lightness index L, color coordinate a, and color coordinate b of the color difference formula of the Hunter in the Lab color system described in are in the resin after the melt polycondensation, the lightness index L is preferably 45 to 70, and the color coordinate a is Preferably, -3 to +3, and color coordinates b are preferably -3 to +3. In the resin after solid-phase polycondensation, the lightness index L is preferably 75 to 90, and the color coordinates a
Is preferably −2 to +2, and the color coordinate b is preferably −4 to
+4.

The thermal stability was measured at 280 ° C. under nitrogen gas flow.
The amount of change Δb (= b′−b) of the color coordinate b ′ after heating and melting for 1 hour from the color coordinate b before heating and melting is, as an absolute value, preferably in the resin after melt polycondensation. 13
Hereinafter, it is more preferably 10 or less, and in the resin after solid-phase polycondensation, it is preferably 3 or less.

The polyester resin obtained by the production method of the present invention is, for example, formed into a preform by injection molding and then stretch blow-molded, or by blow molding a parison formed by extrusion molding. , Formed into a bottle, etc., or formed into a sheet by extrusion, then formed into a tray or container by thermoforming, or biaxially stretched into a film, etc., especially for food packaging It will be useful in the field.

Among them, the preform obtained by injection molding is suitable for forming a bottle by a blow molding method such as a cold parison method in which the preform is biaxially stretched after reheating. For example, carbonated drinks, fruit drinks, It is suitably used as a container for alcoholic beverages, beverages such as tea and mineral water, and liquid seasonings such as soy sauce, sauces, mirin, and dressings.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A slurry of 264 kg (1591 mol) of terephthalic acid and 125 kg (2013 mol) of ethylene glycol was sequentially supplied to an esterification reaction tank maintained at 260 ° C. over 4 hours. The esterification reaction is further performed for 1 hour, and the esterification reaction product (acid value: 45
0 eq / t) was transferred to the polycondensation tank.

Subsequently, 3.6 g of orthophosphoric acid was supplied from the piping to the polycondensation tank into which the esterification reaction product was transferred.
After 5 minutes, 6.5% by weight of magnesium acetate tetrahydrate was added to a weight% ethylene glycol solution so as to have an amount of 0.74 mol as a phosphorus atom (P) per ton of the theoretical yield of the polyester resin. Ethylene glycol solution,
After a further 5 minutes, a 0.48% by weight solution of cobalt acetate tetrahydrate in ethylene glycol was added to the theoretical amount of the polyester resin so that the theoretical yield of the polyester resin was 1.23 moles per tonne of magnesium atom (Mg). After a further 5 minutes, a 1% by weight solution of tetra-n-butyl titanate in ethylene glycol was added to a titanium atom per ton of theoretical polyester resin yield so that the yield was 0.34 moles of cobalt atoms per ton (Co). (T
i) was added sequentially so as to be 0.10 mol, stirred for 5 minutes, and then heated at 260 ° C. for 100 minutes.
While raising the temperature to 280 ° C. and reducing the pressure from normal pressure to 1 mmHg, the intrinsic viscosity of the obtained resin is 0.60 d
1 / g for melt polycondensation, withdrawing it into a strand form from a withdrawal port provided at the bottom of the polycondensation tank, cooling with water, and cutting into a chip shape with a cutter to obtain about 300
kg of polyethylene terephthalate resin (copolymerization amount of diethylene glycol unit: 2.8 mol%) was produced.

With respect to the obtained polyester resin, phosphorus atoms (P), titanium atoms (Ti), cobalt atoms (Co), and divalent metal atoms (M) other than cobalt per ton of the resin are as described below. Was measured for each mole number, intrinsic viscosity, melt polycondensation rate, color tone, and thermal stability, and the results are shown in Table 1.
It was shown to.

Phosphorus atom (P), titanium atom (Ti), edge
Divalent metal atom other than cobalt atom (Co) and cobalt
(M) Quantification 2.0 g of a resin sample was ashed by a conventional method in the presence of sulfuric acid, completely decomposed, and then quantified to 100 ml with distilled water, and quantified by IPC emission spectroscopy.

[0038]Intrinsic viscosity 0.25 g of the freeze-ground resin sample was phenol / tetra
In a mixed solvent of lachloroethane (weight ratio 1/1), the concentration
(C) was changed to 1.0 g / dl at 110 ° C. for 30 minutes.
After dissolving, 30
° C, relative viscosity with the stock solution (η_rel) Measure this relative
Viscosity (η_rel) -1 specific viscosity (η _sp) And concentration
(C) ratio (η_sp/ C), and the density (c)
0.5g / dl, 0.2g / dl, 0.1g / dl
The ratio (η_sp/ C)
From these values, the ratio (η) when the concentration (c) is extrapolated to 0
_sp/ C) was determined as the intrinsic viscosity [η] (dl / g).

[0039]Melt polycondensation rate Intrinsic viscosity of molten polycondensation resin measured by the above method
([Η]_p1) And the esterification reaction products also measured
(Polyester low molecular weight) intrinsic viscosity ([η]_m)
And the polycondensation time (T_m) And the following equation
The melt polycondensation rate V _m(Dl / g / day)
Was. V_m= ｛([Η]_p1− [Η]_m) / T_m｝ × 24

The color resin sample was filled into a column-shaped powder colorimetric cell having an inner diameter of 36 mm and a depth of 15 mm, and was subjected to JIS using a colorimeter ("ND-300A" manufactured by Nippon Denshoku Industries Co., Ltd.). A value obtained by measuring the lightness index L, color coordinates a, and color coordinates b of the color difference formula of the Hunter in the Lab color system described in Reference 1 of Z8730, and the color coordinates a and b at four points by rotating the cell by 90 degrees by the reflection method. Was calculated as a simple average.

Thermal Stability The color coordinate b of the resin measured above was measured under nitrogen gas flow.
From the color coordinates b ′ of the resin after being heated and melted at 0 ° C. for 1 hour, the variation Δb was calculated by the following formula, and the thermal stability was evaluated. Δb = b′−b

Further, the polyester resin chip obtained above was transferred to a stirring crystallization machine (Bepex), and the chip surface was crystallized at 160 ° C.
After drying at 40 ° C. for 3 hours, the mixture is transferred to a stationary solid-phase polycondensation tower, and subjected to solid-phase polycondensation at 210 ° C. under a nitrogen gas flow for a time period at which the intrinsic viscosity of the obtained resin becomes 0.75 dl / g. With respect to the obtained polyester resin, the intrinsic viscosity, the solid-state polycondensation rate, and the thermal stability were measured by the methods described below, and the color tone was measured by the same method as described above. The results are shown in Table 1. .

The procedure was the same as that described above, except that the temperature at which the intrinsic viscosity resin sample was dissolved in the mixed solvent was 120 ° C.

Solid-state polycondensation rate The number-average molecular weight (M _n1 ) obtained from the intrinsic viscosity ([η] _p1 ) of the molten polycondensation resin by the following formula, and the intrinsic viscosity ([η ] the number-average molecular weight determined from the following equation from the _p2) and (M _n2), since the solid phase polycondensation time (T _s), were calculated based on the following equation solid phase polycondensation velocity V _s (/ hr) . M _n1 or M _n2 = ([η] _p1 or [η] _p2 /0.0007
36) ^{1 / 0.685} V _s = ^{_{[(M n2 2 -M n1 2)}} / T s ] × 10 ^-8

Heat Stability After heating and melting at 280 ° C. for 1 hour under flowing nitrogen gas, crystallization treatment at 120 ° C. under vacuum for 12 hours was performed in order to adjust the crystallization level at the time of color tone measurement before heating and melting. Was the same as the method described above.

Examples 2 to 7, Comparative Examples 1 to 4 At the time of melt polycondensation, the compounds shown in Table 1 were used as phosphorus compounds, titanium compounds, cobalt compounds, and divalent metal compounds other than cobalt. Was subjected to melt polycondensation in the same manner as in Example 1 except that the number of moles of each atom shown in Table 1 was used to produce a polyethylene terephthalate resin.
Similarly, the number of moles of each atom, intrinsic viscosity, melt polycondensation rate, color tone, and thermal stability were measured, and the results are shown in Table 1. Furthermore, solid-phase polycondensation was carried out in the same manner as in Example 1, and intrinsic viscosity, solid-state polycondensation rate, color tone, and thermal stability were measured in the same manner. The results are shown in Table 1.

Reference Example 1 In the melt polycondensation, antimony trioxide was used in place of the titanium compound, and the amount of each compound was changed to the number of moles of each atom shown in Table 1, in the same manner as in Example 1. , Melt polycondensation, further solid phase polycondensation to produce polyethylene terephthalate resin, in the same manner, the number of moles of each atom, intrinsic viscosity, melt polycondensation rate, solid phase polycondensation rate, color tone, and thermal stability Was measured, and the results are shown in Table 1.

[0048]

[Table 1]

[0049]

[Table 2]

In Table 1, "O" as a phosphorus compound
“PA” is orthophosphoric acid, “PA” is phosphorous acid, “EAP” is ethyl acid phosphate, and “T” is a titanium compound.
"BT" is tetra-n-butyl titanate, "PTO" is potassium titanium oxalate dihydrate, "AO" in the titanium compound column is antimony trioxide, and "CA" as a cobalt compound is cobalt acetate tetrahydrate. As a divalent metal compound other than cobalt, “MGA” represents magnesium acetate tetrahydrate, and “MNA” represents manganese acetate tetrahydrate.

[0051]

According to the present invention, the composition does not contain an antimony compound, is excellent in polymerizability, and has a color tone of a resin obtained.
In addition, a method for producing a polyester resin having excellent heat stability can be provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C08K 5/56 C08K 5/56 C08L 67/02 C08L 67/02 (72) Inventor Tokio Shinkoku Mie 1 Toho-cho, Yokkaichi-shi F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 4J002 CF051 CF081 DE066 DE076 DE096 DH046 EG046 EW046 EW066 EZ006 4J029 AA03 AB01 AB04 AC01 AE01 BA03 CB06A CC06A HA01 HB01 J571 JC481JB581

Claims (6)

[Claims] 1. A method for producing a polyester resin by polycondensing a dicarboxylic acid component containing an aromatic dicarboxylic acid as a main component and a diol component containing ethylene glycol as a main component through an esterification reaction. Phosphorus atom (P) is 0.1 per ton of theoretical yield.
02-4 mol, titanium atom (Ti) 0.02-0.2
Mol, cobalt atom (Co) is 0.05 to 2 mol, and divalent metal atom (M) other than cobalt is 0.04 to 5 mol.
A method for producing a polyester resin, comprising conducting polycondensation in the presence of a molar amount of a phosphorus compound, a titanium compound, a cobalt compound, and a divalent metal compound other than cobalt. 2. Titanium atom (T) relative to phosphorus atom (P)
i) a molar ratio (Ti / P) of 0.05 to 1, a cobalt atom (Co) molar ratio (Co / P) of 0.1 to 1, and
Molar ratio of divalent metal atoms (M) other than cobalt (M / P)
Is from 0.1 to 10. The method for producing a polyester resin according to claim 1, wherein 3. Titanium atom (T) relative to phosphorus atom (P)
i) a molar ratio (Ti / P) of 0.1 to 0.4, and a cobalt atom (Co) molar ratio (Co / P) of 0.2 to 0.9.
5. The method for producing a polyester resin according to claim 1, wherein the molar ratio (M / P) of divalent metal atoms (M) other than cobalt is 1 to 8. 4. The molar ratio [(Co + M) / Ti] of the sum of a cobalt atom (Co) and a divalent metal atom (M) other than cobalt to a titanium atom (Ti) is 5 to 50. 3. The method for producing a polyester resin according to any one of 3. 5. The method for producing a polyester resin according to claim 1, wherein the divalent metal other than cobalt is magnesium or manganese. 6. The method according to claim 1, wherein the aromatic dicarboxylic acid is terephthalic acid or 2,6-naphthalenedicarboxylic acid.
The method for producing a polyester resin according to any one of the above.