JP2001098063A - Catalyst for polyester preparation and method for preparation of polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst having a high polymerization activity for polyester preparation which catalyst gives a polyester containing only a small amount of acetaldehyde and provide a polyester preparation process using this catalyst. SOLUTION: This catalyst for polyester preparation comprises (A) a hydrolyzed titanium halide, (B) a phosphoric acid metal salt containing at least one element selected from beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese, cobalt and zinc or a slurry obtained by heating a mixture of (A) a hydrolyzed titanium halide, (B) a metal compound containing at least one element selected from beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese, cobalt and zinc, (C) phosphoric acid or a phosphoric acid ester and (D) an aliphatic diol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyester, and more particularly to a catalyst for producing a polyester capable of obtaining a polyester having a low content of acetaldehyde with high polymerization activity, and a method for producing a polyester using the catalyst.

[0002]

BACKGROUND OF THE INVENTION Polyesters, especially polyethylene terephthalate, are excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and are used in various materials including 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.

In view of such prior art, the present inventor has studied and found that a hydrolyzate obtained by hydrolyzing a titanium halide or at least one element selected from titanium halide and another element other than titanium. It has been found that a polycondensation catalyst comprising a hydrolyzate obtained by hydrolyzing a compound or a mixture thereof with a precursor of this compound can produce a polyester with high catalytic activity. However, this polycondensation catalyst may have a high acetaldehyde content in the resulting polyester depending on the preparation conditions, polymerization conditions and the like.

Under such circumstances, the present inventor has further studied and found that a catalyst comprising the above-mentioned hydrolyzate and a specific metal phosphate or a mixture of the above-mentioned hydrolyzate and a specific metal compound with a specific metal compound A catalyst comprising a slurry obtained by heating a mixture of a phosphorus compound and an aliphatic diol has excellent polymerization activity, and has found that the obtained polyester has a low acetaldehyde content, and has completed the present invention. .

[0008]

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned circumstances, and provides a catalyst for producing a polyester capable of obtaining a polyester having a low acetaldehyde content with high polymerization activity, and a method for producing a polyester using the catalyst. It is intended to provide a manufacturing method.

[0009]

SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided a polyester production catalyst comprising a hydrolyzate obtained by hydrolyzing (A) (A-1) a titanium halide or (A-2) a titanium halide and a titanium halide. At least one selected from elements other than
A hydrolyzate obtained by hydrolyzing a mixture of a compound of a certain element or a precursor of the compound, and (B) beryllium,
Magnesium, calcium, strontium, boron,
It is characterized by comprising a metal phosphate containing at least one element selected from aluminum, gallium, manganese, cobalt and zinc.

The metal phosphate is preferably magnesium hydrogen phosphate or trimagnesium diphosphate.
Further, the catalyst for producing a polyester according to another embodiment of the present invention includes a hydrolyzate obtained by hydrolyzing (A) (A-1) a titanium halide or (A-2) a titanium halide and a material other than titanium. (C) beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese A metal compound containing at least one element selected from cobalt and zinc;
It is characterized by comprising a slurry obtained by heating a mixture of (D) at least one phosphorus compound selected from phosphoric acid and a phosphoric ester and (E) an aliphatic diol.

In the present invention, the metal compound (C) is a magnesium compound, the phosphorus compound (D) is phosphoric acid or trimethylphosphoric acid, and the aliphatic diol (E) is ethylene glycol. Is preferred.

The heating temperature of the mixture is 100 to 100.
Preferably, the temperature is 200 ° C. and the heating time is 3 minutes to 5 hours. The method for producing a polyester according to the present invention is a method for producing a polyester 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. It is characterized by:

[0013]

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 halide, or (A-2) a compound of at least one element selected from titanium halide and another element other than titanium, or a compound of this compound. A hydrolyzate obtained by hydrolyzing a mixture with the precursor (hereinafter, these hydrolysates may be referred to as “titanium-containing hydrolysates”) and (B) beryllium, magnesium, calcium, strontium, boron, And a metal phosphate containing at least one element selected from aluminum, gallium, manganese, cobalt and zinc.

The titanium halide used for the preparation of 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, specifically, titanium tetrachloride, tetrabromide Titanium tetrahalides such as titanium 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.

The molar amount of titanium in 100 g of the solid titanium-containing compound is calculated as follows.

[0029]

(Equation 1)

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

[0031]

(Equation 2)

From the above calculation results and the measured value of the amount of adhering water, the amount of water desorbed by heating (% by weight) derived from the hydroxyl group can be obtained 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 metal phosphate (B) used in the present invention
Is beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese,
It is a compound containing at least one element selected from cobalt and zinc.

Specific examples of the metal phosphate (B) include magnesium phosphates such as magnesium hydrogen phosphate, trimagnesium diphosphate and magnesium phosphite; calcium hydrogen phosphate, calcium dihydrogen phosphate;
Calcium phosphate salts such as tricalcium phosphate; strontium phosphate salts such as strontium hydrogen phosphate; aluminum phosphate salts such as aluminum phosphate; manganese phosphate salts such as manganese dihydrogen phosphate and manganese phosphate; And zinc phosphate such as zinc phosphate. Of these, magnesium phosphate is preferable, and magnesium hydrogen phosphate and trimagnesium diphosphate are particularly preferable.

The amount of the above-mentioned titanium-containing hydrolyzate (A) is based on the molar amount of aromatic dicarboxylic acid (in terms of aromatic dicarboxylic acid) in the lower condensate. It is usually in the range of 0.0005 to 0.2 mol%, preferably 0.001 to 0.05 mol%, in terms of metal atom, and the usage ratio of the metal phosphate (B) is in terms of phosphorus atom. Usually, it is in the range of 0.001 to 0.200 mol%, preferably 0.002 to 0.050 mol%. When the amounts of the polycondensation catalyst and the phosphoric acid ester are within the above range, the polymerization activity is excellent, and the obtained polyester has a low acetaldehyde content.

The acetaldehyde content was 2 g for the sample.
After cooling and pulverizing to room temperature, 1 g was collected and charged in a container, 2 cc of an internal standard solution was added to the container, the container was sealed, and then extracted in an oven at 120 ° C. for 1 hour, and then cooled with ice. 5 μl of the supernatant was used as a GC-
Determined by measuring at 6A.

The titanium-containing hydrolyzate (A) can be added to the reactor in the esterification reaction step, or can be added to the first-stage reactor in the polycondensation reaction step. The metal phosphate (B) can be added to the reactor in the esterification reaction step, or can be added to the first-stage reactor in the polycondensation reaction step.
The metal phosphate (B) may be added simultaneously with the titanium-containing hydrolyzate (A), or may be added separately.

The polyester production catalyst according to another embodiment of the present invention comprises the above-mentioned (A) titanium-containing hydrolyzate and (C)
A metal compound containing at least one element selected from beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese, cobalt and zinc; and (D) at least one phosphorus selected from phosphoric acid and phosphate esters It consists of a slurry obtained by heating a mixture of a compound and (E) an aliphatic diol.

The metal compound (C) used in the present invention is
It is a compound containing at least one element selected from beryllium, magnesium, calcium, strontium, boron, aluminum, gallium, manganese, cobalt and zinc.

Specific examples of the metal compound (C) include magnesium compounds such as magnesium acetate, magnesium carbonate and magnesium hydroxide; calcium hydroxide,
Calcium compounds such as calcium acetate and calcium carbonate; strontium compounds such as strontium acetate and strontium carbonate; aluminum compounds such as aluminum acetate, aluminum hydroxide and aluminum carbonate;
Manganese compounds such as manganese acetate; cobalt compounds such as cobalt acetate; zinc compounds such as zinc acetate; and the like, of which magnesium compounds are preferable, and magnesium acetate and magnesium carbonate are particularly preferable.

Specific examples of the phosphorus compound (D) used in the present invention include phosphoric acid and trimethyl phosphate,
Triethyl phosphate, tri-n-butyl phosphate,
Phosphoric acid esters such as trioctyl phosphate, triphenyl phosphate, tricresyl phosphate and the like can be mentioned, and among these, phosphoric acid and trimethyl phosphate are preferable.

The aliphatic diol (E) used in the present invention
Specifically, ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol and the like,
Of these, ethylene glycol is preferred.

The polyester production catalyst according to the present invention comprises:
The titanium-containing hydrolyzate (A) and the metallized compound (C)
And a mixture of the phosphorus compound (D) and the aliphatic diol (E) are heated to obtain a slurry.

In the above mixture, the titanium-containing hydrolyzate (A) is 0.1 to 30% by weight, preferably 0.2 to 20% by weight, more preferably 0.3 to 10% by weight, in terms of titanium atom.
% By weight, and the metal compound (C) is 0.1 to 30% by weight, preferably 0.2 to 20% by weight in terms of metal,
More preferably, the content is 0.3 to 10% by weight, and the phosphorus compound (D) is 0.1 to 30% by weight in terms of phosphorus atom;
Preferably 0.2 to 20% by weight, more preferably 0.3
-10% by weight. The rest is an aliphatic diol (E). The titanium-containing hydrolyzate (A)
And the metal compound (C) are preferably used in the same weight in terms of polymerization activity.

The heating of the mixture is intended to react at least a part of the metal compound (C) dissolved in the aliphatic diol with at least a part of the phosphorus compound (D) dissolved in the aliphatic diol. , Metal compound (C)
When the content ratio of the phosphorus compound (D) is 30% by weight or less, it is preferable in terms of solubility in an aliphatic diol.

The heating temperature of the above mixture depends on the boiling point of the aliphatic diol used, but is usually 50 to 200 ° C., preferably 80 to 190 ° C., more preferably 100 to 190 ° C.
The heating time is 3 minutes to 5 hours, preferably 30 minutes to 4 hours, and more preferably 1 to 4 hours.

When the heating temperature is 50 ° C. or higher, the metal compound (C) dissolved in the aliphatic diol easily reacts with the phosphorus compound (D) dissolved in the aliphatic diol, and the heating temperature is 200 or less. , The aliphatic diol hardly causes a side reaction such as a dehydration reaction.

The ratio of the slurry-like polyester production catalyst to the weight of the mixture of terephthalic acid and ethylene glycol is based on the weight of the metal (derived from the titanium-containing hydrolyzate (A)) in the catalyst. Is usually 0.0
005 to 0.2% by weight, preferably 0.001 to 0.0
It is in the range of 5% by weight.

The above-mentioned slurry-like catalyst for polyester production can be added to the polymerization reactor in the esterification reaction step, or can be added to the first-stage reactor in the polycondensation reaction step.

In the present invention, in addition to the above-mentioned catalyst for producing polyester comprising the hydrolyzate containing titanium (A) and metal phosphate (B) or the above-mentioned catalyst for producing polyester in slurry, the following co-catalyst components Can be used. Examples of the co-catalyst component include compounds of at least one element selected from the group consisting of beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, manganese, cobalt, zinc, germanium, antimony, and phosphorus. ,
Specifically, fatty acid salts such as acetates of these elements, carbonates of these elements, sulfates of these elements, nitrates of these elements, halides such as chlorides, acetylacetonates of these elements Salts and oxides of these elements. Of these, acetate or carbonate is preferred.

More specifically, examples of the co-catalyst 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.

As the cobalt compound, a fatty acid cobalt salt 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 magnesium salts of fatty acids such as magnesium acetate and the like, magnesium carbonate, magnesium chloride, and acetylacetonate salt of magnesium. Particularly, magnesium acetate or magnesium carbonate is preferable.

As the manganese compound, 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, and strontium acetate or strontium carbonate is 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 and germanium acetate. Examples of the antimony compound include antimony dioxide and antimony acetate.

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 co-catalyst 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.

The co-catalyst component can be added to the 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, the co-catalyst component may be added at the same time as the polyester production catalyst or may be added separately.

In the method for producing a polyester according to the present invention, the polyester is produced using the catalyst for producing a polyester as described above. 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, a polyfunctional compound such as trimesic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol can be used as a raw material.

A raw material containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as described above and an aliphatic diol or an ester-forming derivative thereof 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 was added with 1.02 mol per mol 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 by using a device in which two or more esterification reactors are connected in series, under conditions in which 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 first and second stage esterification reaction conditions are respectively in the above ranges, and when the esterification reaction is carried out in three or more stages, the second stage 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. Tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine; tetraethylammonium hydroxide, tetra-n-hydroxide;
Quaternary ammonium hydroxides such as 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, dioxygen in the main chain of polyethylene terephthalate is reduced. This is preferable because the ratio of the ethylene 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 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 0.55 to 0.75 dl / g. In this 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 above-mentioned polycondensation reaction is carried out in the presence of the above-mentioned catalyst for producing polyester. The polycondensation reaction is preferably performed in the presence of a stabilizer.

The stabilizers used as necessary in the polycondensation reaction include phosphates such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate; Phosphites such as phenyl phosphite, trisdodecyl phosphite and trisnonyl phenyl phosphite; acidic phosphorus such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate and the like Acid esters and phosphorus compounds such as phosphoric acid and polyphosphoric acid are used.

The stabilizer is used in an amount of usually 0.001 to 0.1% by weight, preferably 0.002% by weight, based on the weight of the mixture of terephthalic acid and ethylene glycol, as the weight of phosphorus atoms in the stabilizer. 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.

[0086] The polyester obtained from the final polycondensation reactor in this manner 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 performed to perform pre-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.

[0090]

The catalyst for producing polyester according to the present invention can produce a polyester having a high polymerization activity and a low acetaldehyde content.

[0091]

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

[0092]

Example 1 Preparation of Solid Titanium-Containing Compound 500 ml of deionized water 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. Water was removed from the washed titanium hydroxide by vacuum drying at 70 ° C., 10 Torr and 18 hours to obtain a solid titanium-containing compound.

The obtained solid titanium-containing compound was pulverized into particles of about 10 μm before use. A slurry prepared by mixing high-purity terephthalic acid and ethylene glycol is continuously supplied to a reactor in which 33,500 parts by weight of a reaction solution stays during a steady production operation of polyester, and under stirring,
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). The low-order condensate thus obtained was mixed with the solid titanium-containing compound in an amount of 0.021 in terms of titanium atom with respect to the terephthalic acid unit in the low-order condensate.
The amount of magnesium hydrogen phosphate is 0.021 mol% in terms of magnesium atom based on the terephthalic acid unit in the lower condensate, and the amount of phosphoric acid is 0.1 mol in terms of phosphorus atom.
The mixture was added in an amount of 0105 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, and the acetaldehyde content in the obtained polyethylene terephthalate was 60 ppm.

[0096]

Example 2 A polycondensation reaction was carried out in the same manner as in Example 1 except that magnesium triphosphate was used instead of magnesium hydrogen phosphate. The time required for the intrinsic viscosity of polyethylene terephthalate to reach 0.65 dl / g was 67 minutes, and the acetaldehyde content in the obtained polyethylene terephthalate was 57 ppm.

[0097]

Comparative Example 1 A polycondensation reaction was carried out in the same manner as in Example 1 except that magnesium acetate was used instead of magnesium hydrogen phosphate. The time required for the intrinsic viscosity of polyethylene terephthalate to reach 0.65 dl / g is 1
00 minutes, and the acetaldehyde content in the obtained polyethylene terephthalate was 70 ppm.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kensaburo Fukutani 6-1-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture F-term in Mitsui Chemicals, Inc. (reference) 4J029 AA03 AB04 AB07 AC01 AC02 AE01 BA01 BA02 BA03 BA05 BA08 BA10 BB05A BB13A CA06 CB04A CB05A CB06A CB10A CC05A CD03 FC04 FC05 FC08 JB121 JC411 JC421 JC581 JF121 JF131 JF141 JF151 JF181 JF321 JF571 KD01

Claims (6)

[Claims] (A) a hydrolyzate obtained by hydrolyzing (A-1) titanium halide or (A-2) at least one selected from titanium halide and another element other than titanium.
A hydrolyzate obtained by hydrolyzing a mixture of a compound of a certain element or a precursor of the compound, and (B) beryllium,
Magnesium, calcium, strontium, boron,
A catalyst for producing a polyester, comprising: a metal phosphate containing at least one element selected from aluminum, gallium, manganese, cobalt and zinc. 2. The catalyst for producing polyester according to claim 1, wherein the metal phosphate is magnesium hydrogen phosphate or trimagnesium diphosphate. (A) a hydrolyzate obtained by hydrolyzing (A-1) a titanium halide or (A-2) at least one selected from a titanium halide and an element other than titanium.
A hydrolyzate obtained by hydrolyzing a compound of a species element or a mixture thereof with a precursor of the compound, and (C) beryllium,
Magnesium, calcium, strontium, boron,
A metal compound containing at least one element selected from aluminum, gallium, manganese, cobalt and zinc; and (D) at least one phosphorus compound selected from phosphoric acid and a phosphoric ester and (E) an aliphatic diol. A polyester production catalyst comprising a slurry obtained by heating a mixture. 4. The metal compound (C) is a magnesium compound, the phosphorus compound (D) is phosphoric acid or trimethyl phosphate, and the aliphatic diol (E)
Is a catalyst for producing a polyester according to claim 3. 5. The heating temperature of the mixture is 100 to 200 ° C.
The catalyst according to claim 3 or 4, wherein the heating time is 3 minutes to 5 hours. 6. 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 catalyst for producing a polyester according to any one of claims 1 to 5. A method for producing a polyester, comprising: producing a polyester.