JP2001089555A - Catalyst for producing polyester and production of polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst which has an excellent polymerization activity and is used for producing a polyester, and to provide a method for producing the polyester using the catalyst. SOLUTION: This catalyst for producing a polyester comprises a slurry obtained by heating a mixture of (A) (A-1) a hydrolysate obtained by hydrolyzing a titanium compound or (A-2) a hydrolysate obtained by hydrolyzing a mixture of a titanium halide with the compound of at least one element selected from other elements except the titanium or with the precursor of the compound, (B) a basic compound, and (C) an aliphatic diol.

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, and more particularly to a catalyst for producing a polyester having excellent polymerization activity and a method for producing a polyester using the catalyst.

[0002]

BACKGROUND OF THE INVENTION Polyester, for example, polyethylene terephthalate, is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and is used in various kinds of materials such as materials for beverage filling containers such as juices, soft drinks and carbonated drinks. It is suitably used for applications.

[0003] Such polyesters are usually produced using dicarboxylic acids such as aromatic dicarboxylic acids and dihydroxy compounds such as aliphatic diols as raw materials.
Specifically, first, a low-order condensate (ester low polymer) is formed by an esterification reaction between an aromatic dicarboxylic acid and an aliphatic diol, and then the low-order condensate is removed in the presence of a polycondensation catalyst. It is produced by subjecting a glycol reaction (liquid-phase polycondensation) to a high molecular weight and then generally further performing a solid-phase polycondensation.

[0004] In the above-mentioned method for producing polyester, an antimony compound, a germanium compound and the like have been conventionally used as a polycondensation catalyst. However, when the antimony compound is used, the obtained polyester has some problems in terms of heat resistance and transparency as compared with the case where a germanium compound is used.

Further, since the germanium compound is considerably expensive, there is a problem in that the production cost of the polyester is high. In order to reduce the production cost, for example, a process such as collecting and reusing the germanium compound scattered at the time of polymerization is used. The above improvements are being considered.

Under such circumstances, the present inventor has proposed a hydrolyzate obtained by hydrolyzing a titanium halide or a compound of a titanium halide and at least one element selected from elements other than titanium or a compound thereof. It has been found that a polycondensation catalyst comprising a hydrolyzate obtained by hydrolyzing a mixture of a compound and a precursor can produce a polyester with high catalytic activity.

[0007] The present inventors have further studied and found that
The slurry obtained by heating a mixture of the above hydrolyzate, basic compound, and aliphatic diol was found to be more excellent in catalytic activity, and completed the present invention.

[0008]

The object of the present invention is to provide a catalyst for polyester polymerization having excellent polymerization activity and a method for producing a polyester using the catalyst. And

[0009]

SUMMARY OF THE INVENTION The polyester production catalyst according to the present invention comprises (A) a hydrolyzate obtained by hydrolyzing a (A-1) titanium compound or (A-2) a titanium halide and another element other than titanium. A mixture of (B) a basic compound, and (C) an aliphatic diol, by heating a mixture of a compound of at least one element selected from or a mixture of the compound with a precursor of the compound; It is characterized by being composed of a slurry obtained by the above method.

Examples of the basic compound include tetraethylammonium hydroxide, tetramethylammonium hydroxide, aqueous ammonia, sodium hydroxide, potassium hydroxide, N-ethylmorpholine and N-methylmorpholine. Examples of the diol include ethylene glycol.

The method for producing a polyester according to the present invention comprises:
A polyester is produced by polycondensing an aromatic dicarboxylic acid or an ester-forming derivative thereof with an aliphatic diol or an ester-forming derivative thereof in the presence of the polyester production catalyst.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The catalyst for producing polyester and the method for producing polyester according to the present invention will be specifically described below.

The catalyst for producing polyester according to the present invention comprises:
(A) (A-1) a hydrolyzate obtained by hydrolyzing a titanium compound or (A-2) a compound of (A-2) a titanium halide and at least one element selected from elements other than titanium, or a precursor of this compound A hydrolyzate obtained by hydrolyzing a mixture with a body (hereinafter, these hydrolysates may be referred to as “titanium-containing hydrolyzate”), (B) a basic compound, and (C) an aliphatic diol. And a slurry obtained by heating the mixture.

As the titanium compound used for the hydrolysis, titanium alkoxide, titanium halide and the like are used. Use of a titanium halide as a titanium compound is one of preferred embodiments of the present invention. Hereinafter, a method for preparing a titanium-containing hydrolyzate using a titanium halide as a titanium compound will be specifically described, but a hydrolyzate of a titanium alkoxide can be similarly prepared.

The titanium halide used for preparing the titanium-containing hydrolyzate is a compound in which at least one bond between a titanium atom and a halogen atom is present in the molecule, and specifically, titanium tetrachloride, tetraodor Titanium tetrahalides such as titanium iodide and titanium tetraiodide; titanium trihalides such as titanium trichloride; dihalides such as titanium dichloride and titanium monohalide.

The method of hydrolyzing the titanium halide is not particularly limited, and includes, for example, a method of adding a titanium halide to water, a method of adding water to a titanium halide, and a method of adding a titanium halide vapor to water. A gas containing water vapor in a titanium halide, a method of contacting a gas containing titanium halide with a gas containing water vapor, and the like.

As described above, the hydrolysis method is not particularly limited, but in any case, it is necessary to cause a large excess of water to act on the titanium halide to completely advance the hydrolysis. If the hydrolysis does not proceed completely and the resulting hydrolyzate is a partial hydrolyzate as described in JP-B-51-19477, the polycondensation rate may not be sufficient.

The temperature at which the hydrolysis is carried out is usually 100 ° C. or lower, preferably in the range of 0 to 70 ° C. The titanium-containing hydrolyzate used in the present invention is a compound of a titanium halide and at least one element selected from elements other than titanium or a precursor of this compound (hereinafter referred to as a “compound of another element”). ) May be a hydrolyzate obtained by hydrolyzing a mixture of That is, this hydrolyzate is obtained by hydrolyzing a titanium halide in the presence of a compound of another element.

Compounds of other elements which may coexist during the hydrolysis of titanium halide include beryllium, magnesium, calcium, strontium, barium,
Scandium, yttrium, lanthanum, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium,
Copper, zinc, boron, aluminum, gallium, silicon,
Examples include a compound of at least one element selected from the group consisting of germanium, tin, antimony, and phosphorus (hereinafter, these elements are referred to as “other elements”) or a precursor of this compound. As a compound of the above other elements,
For example, hydroxide and the like can be mentioned.

The compounds of these other elements can be used alone or in combination of two or more. The method of hydrolyzing a mixture of a titanium halide and a compound of another element is not particularly limited.For example, a method of adding a titanium halide to water in which a compound of another element is dissolved or suspended, a method of adding titanium in water A method of adding a mixture of a halide and a compound of another element, a method of adding water to a mixture of a titanium halide and a compound of another element, and a method of dissolving or suspending a compound of another element in a titanium halide. A method of adding turbid water, a method of passing a gas containing titanium halide vapor in water in which a compound of another element is dissolved or suspended, and a method of vaporizing titanium halide and a vapor of a compound of another element in water. Gas containing water, gas containing water vapor in a mixture of titanium halide and a compound of another element, water in titanium halide Gas and a gas containing vapor of another element compound, a method of contacting a gas containing titanium halide with a gas containing vapor of a compound of another element and a gas containing water vapor, and the like. .

In the hydrolysis, the molar ratio (E / Ti) of titanium (Ti) in the titanium halide to the other element (E) in the compound of the other element is 1/50 to 50. / 1
Is desirably within the range. The temperature at which the hydrolysis is carried out is usually 100 ° C. or lower, preferably in the range of 0 to 70 ° C.

When a titanium halide or a mixture of a titanium halide and a compound of another element is hydrolyzed, the liquid property becomes acidic due to hydrogen halide generated by hydrolysis of the titanium halide. Since hydrolysis may not be completed due to this acidity, a base may be added for neutralization. As the base used here,
Periodic Table of Elements such as Ammonia Water, Sodium Hydroxide, Potassium Hydroxide, and Magnesium Hydroxide Cycles of Elements 1 and 2 Hydroxides or Elements such as Sodium Carbonate, Sodium Bicarbonate, Potassium Carbonate, and Potassium Bicarbonate Examples include carbonic acid (hydrogen) compounds of Group 1 and 2 elements, urea, and basic organic compounds. The pH of the neutralization end point is preferably 4 or more, and the neutralization is preferably performed at 70 ° C. or less.

The hydrolyzate obtained by the above hydrolysis is a hydrous hydroxide gel also called orthotitanic acid or a hydrous composite hydroxide gel containing other elements at this stage. This hydrous hydroxide gel or hydrous composite hydroxide gel can be used as it is as a polycondensation catalyst, but is preferably dehydrated and dried to obtain a solid hydrolyzate (solid titanium-containing compound).

Drying of the hydrolyzate can be carried out under normal pressure or reduced pressure, in a solid state or in a state of being suspended in a liquid phase having a boiling point higher than that of water. The drying temperature is not particularly limited.
The temperature is preferably not less than 350 ° C. The water-soluble hydroxide gel or the water-containing composite hydroxide gel may be washed with water before drying, or the solid titanium-containing compound may be washed with water after drying to remove water-soluble components. It is preferable that drying be performed promptly.

The composition of the solid titanium-containing compound thus obtained depends on the presence or absence and amount of other coexisting elements, the presence or absence of water washing, the drying method, and the degree of drying. (Ti) molar ratio (OH / T
i) is usually more than 0.09 and less than 4, preferably 0.1
To 3, more preferably 0.1 to 2 in terms of polycondensation activity. The molar ratio between the hydroxyl group and titanium can be determined by measuring the attached moisture and the heat desorbed moisture.

The molar ratio between the hydroxyl group and titanium is specifically determined as follows. In order to determine the hydroxyl group content in the solid titanium-containing compound, first, the amount of attached moisture is measured by a Karl Fischer moisture meter. Next, the weight loss due to heating by heating to 600 ° C. is measured by thermogravimetric analysis.
It is considered that the adhered water is desorbed by heating to 600 ° C., and the hydroxyl group is desorbed as water. Therefore, the hydroxyl group content is determined from the value obtained by subtracting the amount of adsorbed water from the loss on heating. The titanium content in the solid titanium-containing compound is determined by a high-frequency plasma emission analyzer. The OH / Ti ratio is determined from the titanium content and the hydroxyl group content.

More specifically, for example, a solid titanium-containing compound using ammonia as a neutralizing agent at the time of preparation, the titanium content in the solid titanium-containing compound is 46% by weight, and the amount of attached moisture is 6.73% by weight, 600
The OH / Ti ratio is calculated as follows when the heat loss to 9.degree. C. is 9.67% by weight, the nitrogen content is 1.3% by weight, and the chlorine content is 14 ppm. The nitrogen content is analyzed by a trace total nitrogen analyzer (chemiluminescence method), and the chlorine content is analyzed by chromatography. Solid titanium-containing compound 1
The molar amount of titanium in 00 g is calculated as follows.

[0028]

(Equation 1)

Since nitrogen and chlorine in the solid titanium-containing compound are desorbed as ammonia and hydrogen chloride, respectively, the amount of desorbed water by heating (% by weight) can be determined as follows.

[0030]

(Equation 2)

From the above calculation results and the measured value of the amount of attached water, the amount of water desorbed by heating (% by weight) derived from the hydroxyl group can be determined as follows. 8.090-6.73 = 1.360 From this, the molar amount of the hydroxyl group contained in 100 g of the solid titanium-containing compound can be determined as follows.

(1.360 / 18) × 2 = 0.511 From the above, the molar ratio (OH / Ti ratio) between the titanium content and the hydroxyl group content in the solid titanium-containing compound is determined. 0.1511 ÷ 0.9607 = 0.157

In this solid titanium-containing compound, a hydroxyl group remains even at a temperature at which a polycondensation reaction is performed, for example, at about 280 ° C. When the solid titanium-containing compound contains another element, the molar ratio (E / Ti) between titanium (Ti) and the other element (E) in the compound is 1/50 to 50 /.
1, preferably 1/40 to 40/1, more preferably 1/30 to 30/1.

The titanium-containing hydrolyzate such as the above-mentioned hydrous hydroxide gel, hydrous composite hydroxide gel, and solid titanium-containing compound has a chlorine content of usually 0 to 10000 ppm, preferably 0 to 100 ppm.

The basic compound used in the present invention is a compound that shows basicity in an aqueous solution.
Examples include tetraethylammonium hydroxide, tetramethylammonium hydroxide, aqueous ammonia, sodium hydroxide, calcium hydroxide, N-ethylmorpholine, N-methylmorpholine and the like, with tetraethylammonium hydroxide being preferred.

Specific examples of the aliphatic diol used in the present invention include ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol and the like. Preferably, it is used.

The polyester production catalyst according to the present invention comprises:
It is obtained as a slurry by heating a mixture of the titanium-containing hydrolyzate, the basic compound, and the aliphatic diol.

In the above mixture, the titanium-containing hydrolyzate is contained in a ratio of 0.05 to 30% by weight, preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight. 0.5 to 50% by weight, preferably 1%, of the basic compound
-40% by weight, more preferably 2-30% by weight. The rest is an aliphatic diol.

When the content ratio of the titanium-containing hydrolyzate is 0.05
When the content is not less than% by weight, the amount of the aliphatic diol to be added can be reduced, and the polymerization rate is increased. Further, when the content of the titanium-containing hydrolyzate is 50% by weight or less, coloring during heating is small, and the hue of the polyester polymerized by using this becomes good.

When the content of the basic compound is 0.5% by weight or more, the catalytic activity is improved. When the content of the basic compound is 30% by weight or less, coloring during heating is small. The heating temperature of the above mixture is usually 100 to 300 ° C,
Preferably 120-250 ° C, more preferably 140-
200 ° C., heating time is 5 minutes to 10 hours, preferably 30 minutes
Desirably, it is between minutes and 8 hours.

The proportion of the catalyst used for the production of polyester is usually 0.1% by weight of the metal in the catalyst with respect to the weight of the mixture of terephthalic acid and ethylene glycol.
0005-0.2% by weight, preferably 0.001-0.
It is in the range of 05% by weight.

The polyester production catalyst can be added to the polymerization reactor in the esterification reaction step,
It can also be added to the first stage reactor of the polycondensation reaction step.

In the present invention, the following co-catalyst components can be used in addition to the above-mentioned catalyst for producing polyester. This co-catalyst component includes beryllium, magnesium, calcium, strontium, barium, boron,
Aluminum, gallium, manganese, cobalt, zinc,
Examples include compounds of at least one element selected from the group consisting of germanium, antimony, and phosphorus. Specifically, fatty acid salts such as acetates of these elements, carbonates of these elements, and sulfuric acids of these elements Salts, halides such as nitrates and chlorides of these elements, acetylacetonate salts of these elements, oxides of these elements, and the like can be given. Of these, acetate or carbonate is preferred.

Examples of the phosphorus compound include phosphates of at least one metal selected from transition metals of the first and second groups of the periodic table, fourth period of the periodic table, zirconium, hafnium and aluminum. Phosphites.

More specifically, examples of the cocatalyst component include aluminum compounds such as aluminum salts of fatty acids such as aluminum acetate, aluminum carbonate, aluminum chloride, and acetylacetonate salt of aluminum. preferable.

As the barium compound, barium salts of fatty acids such as barium acetate, barium carbonate, barium chloride,
Examples include barium acetylacetonate, and barium acetate or barium carbonate is particularly preferable.

Examples of the cobalt compound include fatty acid cobalt salts such as cobalt acetate, cobalt carbonate, cobalt chloride,
Acetyl acetonate salt of cobalt and the like are mentioned, and particularly, cobalt acetate or cobalt carbonate is preferable.

Examples of the magnesium compound include fatty acid magnesium salts such as magnesium acetate, magnesium carbonate, magnesium chloride, and acetylacetonate salt of magnesium. Particularly preferred is magnesium acetate or magnesium carbonate.

The manganese compounds include manganese salts of fatty acids such as manganese acetate, manganese carbonate, manganese chloride,
Manganese acetylacetonate salt and the like can be mentioned, and manganese acetate or manganese carbonate is particularly preferable.

Examples of the strontium compound include strontium salts of fatty acids such as strontium acetate, strontium carbonate, strontium chloride, and acetylacetonate salt of strontium. Strontium acetate and strontium carbonate are particularly preferable.

Examples of the zinc compound include zinc salts of fatty acids such as zinc acetate, zinc carbonate, zinc chloride, and acetylacetonate salt of zinc. Zinc acetate and zinc carbonate are particularly preferred.

Examples of the germanium compound include germanium dioxide, germanium acetate and the like. Examples of the antimony compound include antimony dioxide and antimony acetate.

Among the phosphorus compounds, phosphates include lithium phosphate, lithium dihydrogen phosphate, dilithium hydrogen phosphate, sodium phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium phosphate, Examples include potassium dihydrogen acid, dipotassium hydrogen phosphate, strontium phosphate, strontium dihydrogen phosphate, distrontium hydrogen phosphate, zirconium phosphate, barium phosphate, aluminum phosphate, and zinc phosphate. Of these, sodium phosphate, sodium dihydrogen phosphate,
Disodium hydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate are preferably used.

Among the phosphorus compounds, the phosphite includes at least one metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals of the fourth period of the periodic table, zirconium, hafnium and aluminum. An acid salt is used, specifically, lithium phosphite, sodium phosphite, potassium phosphite, strontium phosphite, zirconium phosphite, barium phosphite, aluminum phosphite, zinc phosphite And the like. Of these, sodium phosphite and potassium phosphite are particularly
It is preferably used.

Among these, magnesium compounds such as magnesium carbonate and magnesium acetate; calcium compounds such as calcium carbonate and calcium acetate; and zinc compounds such as zinc chloride and zinc acetate are preferred.

These cocatalyst components can be used alone or in combination of two or more. Such a co-catalyst component includes titanium (titanium and other elements when other elements are contained) (T
In a molar ratio [(M) / (Ti)] between i) and the metal atom (M) in the promoter component, 1/50 to 50/1, preferably 1/40 to 40/1, more preferably 1 / 30-3
Preferably, it is used in an amount in the range of 0/1. In addition,
When a phosphorus compound such as a phosphate or a phosphite is used, it is calculated in terms of metal atoms contained in the phosphorus compound.

The cocatalyst component can be added to the polymerization reactor in the esterification reaction step, or can be added to the first-stage reactor in the liquid-phase polycondensation reaction step. When the co-catalyst component is added in the esterification reaction step,
It may be added at the same time as the polyester production catalyst,
It may be added separately.

In the method for producing a polyester according to the present invention, the polyester is produced using the above-mentioned catalyst for producing a polyester. In the present invention, the polyester is produced using an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol or an ester-forming derivative thereof as raw materials.

Specific examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid and the like.

Specific examples of the aliphatic diol include ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol and the like.

In the present invention, an aliphatic dicarboxylic acid such as adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, or an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid may be used as a raw material together with an aromatic dicarboxylic acid. Alicyclic glycols such as cyclohexanedimethanol, bisphenol, hydroquinone, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, 1,3-bis (2-hydroxyethoxy) benzene And aromatic diols such as 1,4-bis (2-hydroxyethoxy) benzene and the like can be used as raw materials.

In the present invention, polyfunctional compounds such as trimesic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol can be used as raw materials.

The raw material containing the above-described aromatic dicarboxylic acid or its ester-forming derivative and the aliphatic diol or its ester-forming derivative is esterified. Specifically, first, a slurry containing an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol or an ester-forming derivative thereof is prepared.

The slurry contains 1.02 parts per mole of aromatic dicarboxylic acid or its ester-forming derivative.
〜1.4 mol, preferably 1.03-1.3 mol of aliphatic diol or its ester-forming derivative. This slurry is continuously supplied to the esterification reaction step.

The esterification reaction is preferably carried out using an apparatus in which two or more esterification reactors are connected in series, under conditions where the aliphatic diol is refluxed, and water produced by the reaction is removed from the system by a rectification column. It is performed while removing. The reaction conditions for performing the esterification reaction are such that the temperature of the first-stage esterification reaction is usually 240 to 270 ° C., preferably 245 to 270 ° C.
265 ° C. and the pressure is usually 0.2-3 kg / cm ²
G, preferably 0.5-2 kg / cm ² G, and the temperature of the final esterification reaction is usually 250-280.
° C, preferably 255-275 ° C, and the pressure is usually 0
~ 1.5 kg / cm ² G, preferably 0-1.3 kg / cm
cm ² G.

When the esterification reaction is carried out in two stages, the conditions of the first and second stages of esterification are respectively within the above ranges. The reaction conditions of the esterification reaction from the first stage to the stage immediately before the last stage are those between the above-mentioned first-stage reaction conditions and the last-stage reaction conditions.

For example, when the esterification reaction is carried out in three stages, the reaction temperature of the second stage esterification reaction is usually 245-275 ° C., preferably 250-270 ° C.
° C, and the pressure is usually 0 to ² kg / cm ² G, preferably 0.2 to 1.5 kg / cm ² G. The conversion of these esterification reactions, at each stage,
Although there is no particular limitation, it is preferable that the degree of the increase in the esterification reaction rate in each stage is smoothly distributed, and that the final stage of the esterification reaction product is usually 9%.
It is desirable to reach 0% or more, preferably 93% or more.

An esterified product (low-order condensate) is obtained by these esterification steps, and the number-average molecular weight of the esterified product is usually from 500 to 5,000. Such an esterification reaction can be carried out without adding an additive other than the aromatic dicarboxylic acid and the aliphatic diol, and can be carried out in the presence of the above-mentioned catalyst for producing polyester. . Triethylamine, tri-n-
Tertiary amines such as butylamine and benzyldimethylamine; tetraethylammonium hydroxide,
A quaternary ammonium hydroxide such as n-butylammonium and trimethylbenzylammonium hydroxide; when a small amount of a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate, and sodium acetate is added, the quaternary ammonium hydroxide in the main chain of polyethylene terephthalate can be obtained. It is preferable because the ratio of the dioxyethylene terephthalate component unit can be maintained at a relatively low level.

Next, the obtained esterified product is supplied to a liquid phase polycondensation step. In this liquid-phase polycondensation step, the polyester is heated to a temperature not lower than the melting point of the obtained polyester under reduced pressure in the presence of the above-mentioned polyester-producing catalyst. Condenses.

The polycondensation reaction in such a liquid phase may be performed in one stage or may be performed in a plurality of stages. When the polycondensation reaction is performed in a plurality of stages, the reaction temperature of the first stage polycondensation is usually from 250 to 290C, preferably from 26 to 290C.
0 to 280 ° C., and the pressure is usually 500 to 20 Torr.
r, preferably 200 to 30 Torr, the temperature of the final polycondensation reaction is usually 265 to 300 ° C, preferably 270 to 295 ° C, and the pressure is usually 10 to 0.1 Torr.
rr, preferably 5 to 0.5 Torr.

When the polycondensation reaction is carried out in two stages,
The conditions of the polycondensation reaction of the first and second stages are respectively in the above ranges.
The reaction conditions for the polycondensation reaction from the first stage to the last stage before the last stage are those between the above-mentioned first stage reaction conditions and the last stage reaction conditions.

For example, when the polycondensation reaction is carried out in three stages, the reaction temperature of the second stage polycondensation reaction is usually 26.
0-295 ° C., preferably 270-285 ° C., and the pressure is usually in the range of 50-2 Torr, preferably 40-5 Torr. The intrinsic viscosity (IV) reached in each of these polycondensation reaction steps is not particularly limited, but it is preferable that the degree of increase in the intrinsic viscosity in each stage be distributed smoothly. The intrinsic viscosity (IV) of the polyester obtained from the final stage polycondensation reactor is usually 0.35 to
0.80 dl / g, preferably 0.45 to 0.75 dl
/ G, more preferably in the range of 0.55 to 0.75 dl / g.

In the present specification, the intrinsic viscosity is calculated from the solution viscosity measured at 25 ° C. after heating and dissolving 1.2 g of polyester in 15 cc of o-chlorophenol.

The density of the polyester is usually 1.
It is desirably 33 to 1.35 g / cm ³ . In the present specification, the density of the polyester is determined by a density gradient tube using a mixed solvent of carbon tetrachloride and heptane by 23%.
It is measured at a temperature of ° C.

The polycondensation reaction as described above is preferably carried out in the presence of a stabilizer. Examples of the stabilizer used as needed in the polycondensation reaction include phosphate esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, and tricresyl phosphate; triphenyl phosphite Phosphites such as tris-dodecyl phosphite and tris nonyl phenyl phosphite; acid phosphates such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate and dioctyl phosphate; Phosphorus compounds such as phosphoric acid and polyphosphoric acid are used.

The amount of the stabilizer used is usually 0.001 to 0.1% by weight, preferably 0.002% by weight, as the weight of phosphorus atoms in the stabilizer, based on the weight of the mixture of terephthalic acid and ethylene glycol. ０．０0.02% by weight. The stabilizer can be supplied at the stage of the esterification reaction step or can be supplied to the first stage reactor of the polycondensation reaction step.

The polyester obtained from the final polycondensation reactor in this way is usually formed into particles (chips) by a melt extrusion molding method. Such a granular polyester is usually 2.0 to 5.0 mm, preferably 2.2.
It is desirable to have an average particle size of ~ 4.0 mm. The granular polyester that has undergone the liquid phase polycondensation step in this way is
Usually fed to a solid phase polycondensation step.

The granular polyester may be heated to a temperature lower than the temperature at which the solid-phase polycondensation is carried out to carry out preliminary crystallization, and then supplied to the solid-phase polycondensation step. Such a pre-crystallization step may be performed by heating the granular polyester in a dry state, for example, at a temperature of 120 to 200 ° C, preferably 130 to 180 ° C for 1 minute to 4 hours,
Alternatively, it may be carried out by heating the granular polyester in a steam atmosphere, a steam-containing inert gas atmosphere or a steam-containing air atmosphere, for example, at a temperature of 120 to 200 ° C. for 1 minute or more.

The solid phase polycondensation step in which such a granular polyester is supplied comprises at least one stage, and the polycondensation temperature is usually 190 to 230 ° C., preferably 195 to 225.
° C and the pressure is usually 1 kg / cm ² G to 10 Torr,
The solid-phase polycondensation reaction is preferably carried out under an atmosphere of an inert gas such as a nitrogen gas, an argon gas, or a carbon dioxide gas under the conditions of normal pressure to 100 Torr. Among these inert gases, nitrogen gas is preferred.

The intrinsic viscosity of the polyester thus obtained is usually at least 0.50 dl / g, preferably at least 0.70 dl / g.
It is desirably 2 dl / g or more. The density of this polyester is usually at least 1.37 g / cm ³ , preferably at least 1.38 g / cm ³ , more preferably at least 1.39 g / cm ^3.
/ Cm ³ or more.

[0081]

According to the present invention, a polyester having a desired intrinsic viscosity can be obtained in a short time.

[0082]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0083]

Example 1 Preparation of titanium-containing hydrolyzate 500 m of deionized water was placed in a 1000 ml glass beaker.
After weighing 1 and cooling in an ice bath, 5 g of titanium tetrachloride was added dropwise with stirring. When the generation of hydrogen chloride stopped, the solution was taken out of the ice bath, and 25% aqueous ammonia was added dropwise with stirring to adjust the pH of the solution to 8. The generated precipitate of titanium hydroxide was filtered with a pressure filter at a pressure of 3 kg / cm ² ,
Sorted out. Thereafter, the obtained precipitate of titanium hydroxide was washed five times with deionized water. The solid-liquid separation after the washing was performed by pressure filtration at a pressure of 3 kg / cm ^{2 in} the same manner as described above.
The washed titanium hydroxide was dried under reduced pressure at 70 ° C. and 10 Torr for 18 hours to remove water, thereby obtaining a solid titanium-containing compound.

The obtained solid titanium-containing compound was pulverized into particles of about 10 μm before use as a polycondensation catalyst. Preparation of Catalyst for Polyester Production 10 g of the above-mentioned hydrolyzate containing titanium, 65 g of ethylene glycol and 25 g of tetraethylammonium hydroxide
g) was heated at 190 ° C. for 3 hours to obtain a catalyst for polyester production.

Production of Polyester A slurry prepared by mixing high-purity terephthalic acid and ethylene glycol is continuously supplied to a reactor in which 33500 parts by weight of a reaction solution stays during a steady operation, and the mixture is stirred.
The esterification reaction was performed in a nitrogen atmosphere at 260 ° C. and 0.9 kg / cm ² -G. The slurry of high-purity terephthalic acid and ethylene glycol contains 6458 parts by weight of high-purity terephthalic acid and ethylene glycol, respectively.
Hour, by mixing at a rate of 2615 parts by weight / hour.

In the esterification reaction, a mixed solution of water and ethylene glycol was distilled off. The esterification reaction product (lower condensate) was continuously extracted out of the system while controlling the average residence time to be 3.5 hours.

The low-order polycondensate of ethylene glycol and terephthalic acid obtained above has a number average molecular weight of 600 to 1
300 (trimer to pentamer). To the low-order condensate thus obtained, a catalyst for polyester production was added in an amount of 0.00 in terms of titanium atom with respect to 1 mol of terephthalic acid units in the low-order condensate.
The solution was added in an amount of 21 mol%, and a liquid phase polycondensation reaction was performed at 285 ° C. and 1 Torr. The time required for the intrinsic viscosity of polyethylene terephthalate to reach 0.65 dl / g was 57 minutes.

[0088]

Comparative Example 1 Except that the titanium-containing hydrolyzate was used in an amount of 0.021 mol% in terms of titanium atom per mol of terephthalic acid unit in the lower condensate, instead of the catalyst for producing polyester. A polycondensation reaction was carried out in the same manner as in Example 1. The intrinsic viscosity of polyethylene terephthalate is 0.65
The time required to reach dl / g was 3 hours and 55 minutes. The acetaldehyde content in the polyethylene terephthalate was 52 ppm.

[0089]

Comparative Example 2 Preparation of Polycondensation Catalyst (1) A mixture of 10 g of the above-mentioned hydrolyzate containing titanium, 65 g of ethylene glycol and 25 g of acetic acid was heated at 190 ° C. for 3 hours to obtain polycondensation catalyst (1). Was.

[0090] Instead of producing catalyst for polyester production of polyester, use in an amount of 0.021 mol% in terms of titanium atom the polycondensation catalyst (1) with respect to the terephthalic acid unit mole of the low condensate A polycondensation reaction was carried out in the same manner as in Example 1 except for this. The intrinsic viscosity of polyethylene terephthalate is 0.65 dl /
The time required to reach g was 46 minutes. The acetaldehyde content in the polyethylene terephthalate was 58 ppm.

[0091]

Comparative Example 3 Preparation of Polycondensation Catalyst (2) A mixture of 10 g of the above titanium-containing hydrolyzate and 90 g of ethylene glycol was heated at 190 ° C. for 3 hours to obtain a polycondensation catalyst (2).

[0092] Instead of producing catalyst for polyester production of polyester, use in an amount of 0.021 mol% in terms of titanium atom the polycondensation catalyst (2) relative to the terephthalic acid unit mole of the low condensate A polycondensation reaction was carried out in the same manner as in Example 1 except that the reaction was carried out.
The intrinsic viscosity of polyethylene terephthalate is 0.65 dl
/ G was 1 hour and 50 minutes.

Continued on the front page (72) Inventor Hidefumi Hori 1-2-1, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Chemicals, Inc. (72) Inventor Katsuyuki Sakai 6-chome, Waki-cho, Kuga-gun, Yamaguchi Prefecture 1-2 No.2 in Mitsui Chemicals, Inc. (72) Inventor Shoji Hiraoka 1-2-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture F-term in Mitsui Chemicals, Inc. 4J029 AA03 AB04 BA03 JA091 JA171 JC091 JC291 JF031 JF041 JF321

Claims (4)

[Claims] 1. A compound of (A) a hydrolyzate obtained by hydrolyzing (A-1) a titanium compound or a compound of (A-2) a titanium halide and at least one element selected from elements other than titanium. Or a hydrolyzate obtained by hydrolyzing a mixture of the compound and a precursor thereof, (B) a basic compound,
(C) A polyester production catalyst comprising a slurry obtained by heating a mixture with an aliphatic diol. 2. The base compound is at least one compound selected from tetraethylammonium hydroxide, tetramethylammonium hydroxide, aqueous ammonia, sodium hydroxide, potassium hydroxide, N-ethylmorpholine, and N-methylmorpholine. The catalyst for producing a polyester according to claim 1. 3. The catalyst according to claim 1, wherein the aliphatic diol is ethylene glycol. 4. Polycondensation of an aromatic dicarboxylic acid or an ester-forming derivative thereof with an aliphatic diol or an ester-forming derivative thereof in the presence of the polyester production catalyst according to any one of claims 1 to 3. A method for producing a polyester, comprising: producing a polyester.