JP4650001B2 - Polyester polycondensation catalyst, production method thereof, and production method of polyester resin using the polycondensation catalyst - Google Patents

Description

  The present invention relates to a polyester polycondensation catalyst, in particular, a polyester polycondensation catalyst containing titanium element, magnesium element and phosphorus element having good storage stability, a method for producing the same, and a polyester resin using the polycondensation catalyst. It relates to a manufacturing method.

  Conventionally, polyester is widely used in various uses such as containers such as bottles, films, sheets, and fibers because of its excellent chemical and physical properties. The polyester is generally produced through an esterification reaction or a transesterification reaction and a melt polycondensation reaction, and if necessary, in particular for containers, by a solid phase polycondensation reaction. Compounds such as antimony, germanium, and titanium are used as polycondensation catalysts.

  However, polyesters using antimony compounds as polycondensation catalysts reduce the amount of antimony compounds used due to their unique dullness, safety and hygiene concerns, and environmental concerns. There has been a strong demand for the production of a polycondensation catalyst instead of these methods. In addition, in the polyester having a germanium compound as a polycondensation catalyst, although it is suitable in terms of transparency and safety and hygiene, the germanium compound itself is extremely expensive and economical disadvantages cannot be avoided. As for germanium compounds, there has been a strong demand for the appearance of a method for reducing the amount used or a polycondensation catalyst instead. On the other hand, titanium compounds are attracting attention because they are inexpensive and have no concerns about safety and hygiene, and have been used instead of antimony compounds and germanium compounds.

  For example, by adding a specific titanium compound and an ethylene glycol solution having a water concentration and an ethylene glycol solution having a specific phosphorus concentration to the reaction system, a polyester resin having excellent dimensional accuracy of the stopper when used as a bottle is produced. A method is known (Patent Document 1). Specifically, in the production method described in the document, each of titanium, magnesium and phosphorus compounds is divided into ethylene glycol solutions and added to the reaction system.

In addition, as a liquid catalyst capable of producing a polyester excellent in color tone and transparency at a high reaction rate, a metal element of Group 4A of the periodic table such as titanium element and a metal element of Group 4A of the periodic table such as magnesium element A liquid catalyst containing a specific amount of alkenyl and having a specific turbidity is known (Patent Document 2). Specifically, in the method for producing a polyester described in this document, a liquid catalyst containing a titanium element and a magnesium element is added to the reaction system, and then a phosphorus compound solution is added to the reaction system.
In the methods of Patent Documents 1 and 2, a solution containing titanium element, magnesium element, and phosphorus element is dividedly added in two or three stages. However, when adopting divided addition in industrial production, productivity or gain is obtained. From the viewpoint of the performance of the polyester to be obtained and the stability of product quality, it is necessary to strictly control the addition method and the like in order to bring the polycondensation catalyst component to a predetermined concentration in the reaction system.

On the other hand, as a catalyst for polycondensation capable of producing an excellent quality polyester with high catalytic activity, a reaction product of a specific titanium compound component, a specific phosphorus compound component and a specific alkaline earth metal compound component A polyester production catalyst has been proposed. Specifically, an ethylene glycol solution of trimethyl phosphate is added to a mixed solution obtained by adding an ethylene glycol solution of a titanium compound to an ethylene glycol solution of magnesium acetate. An example of preparing a catalyst solution is described (Patent Document 3). Since the catalyst solution is a catalyst solution containing a titanium element, a phosphorus element, and a magnesium element, it is not necessary to separately add catalyst components to the reaction system, and is considered an industrially advantageous method. However, according to the study by the present inventor, the catalyst solution lacks long-term stability, becomes cloudy after being stored for several days, and deposits of metal components are seen to form a slurry. As a result, it becomes difficult to accurately add the catalyst solution to the polycondensation reaction of polyester, and the slurry-like catalyst settles and scales in the catalyst storage tank or the catalyst addition line, resulting in poor handling. It turned out that there was a problem.

JP 2004-124068 A JP 2004-292803 A JP 2004-224858 A

  The present invention has no problem of divided addition during production of a polyester using a titanium compound, an alkaline earth metal compound, and a phosphorus compound, is excellent in long-term storage stability and reactivity, and the resulting polyester has a good color tone. A liquid polyester polycondensation catalyst and a method for producing the same are provided. Furthermore, it is providing the manufacturing method of the polyester resin using this catalyst for polycondensation.

（上記式中、Ｒ、Ｒ'は炭素数１以上６以下のアルキル基、シクロヘキシル基、または
アリール基を示す）
他の要旨は、上記のポリエステル重縮合用触媒の製造方法により得られた触媒を用いる、ポリエステル樹脂の製造方法、に存する。
As a result of intensive studies, the present inventor has found that a liquid mixture obtained by mixing an alcohol, an alkaline earth metal compound, an acidic phosphate ester compound and a titanium compound in a specific order solves the above problems.
That is, the gist of the present invention, (i) an alcohol, an alkaline earth metal compound, and mixing in advance the acidic phosphoric acid ester compound, and, (ii) step (i) further titanium mixed solvent solution obtained in mixing the compound, it has a, acidic phosphoric acid ester compound is characterized Rukoto represented by the following general formula (1), titanium, a liquid polyester polycondensation containing an alkaline earth metal, and phosphorus A method for producing a catalyst.

(In the above formula, R and R ′ are alkyl groups having 1 to 6 carbon atoms, cyclohexyl groups, or
Represents an aryl group)
Another gist lies in a method for producing a polyester resin using the catalyst obtained by the method for producing a polyester polycondensation catalyst.

  According to the present invention, there is no problem of divided addition during production of polyester using a titanium compound, an alkaline earth metal compound, and a phosphorus compound, and the liquid polyester polycondensation catalyst of the present invention is a catalyst component deposited by long-term storage, etc. Thus, it is possible to provide a polyester resin which is excellent in long-term storage stability, excellent in reactivity and excellent in quality such as color tone.

  The description of the constituent requirements described below is a representative example of the embodiment of the present invention, and is not limited to these contents.

<Liquid polyester polycondensation catalyst and production thereof>
The liquid polyester polycondensation catalyst of the present invention is obtained by further mixing a titanium compound with a mixed liquid obtained by previously mixing an alcohol, an alkaline earth metal compound, and an acidic phosphate compound. .

(alcohol)
The alcohol used in the present invention is not particularly limited as long as it becomes uniform and transparent by mixing an alkaline earth metal compound, an acidic phosphate compound and a titanium compound at room temperature, and among them, a monovalent alcohol and / or diol. Is preferably used. As the monovalent alcohol, for example, an alcohol having 1 to 5 carbon atoms is preferable, an alcohol having 1 to 3 carbon atoms is more preferable, and ethanol is particularly preferable. Since polyester is produced from dicarboxylic acid and diol as raw materials, diol, particularly alkylene glycol is preferred. Examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propane. Examples include diol, polyethylene glycol, polytetramethylene ether glycol and the like. The alkylene glycol is preferably an alkylene glycol that is a raw material for polyester, and an alkylene glycol having 2 to 4 carbon atoms is particularly preferable because it is often used as a raw material for polyester.

In the production of the polyester described later, it is preferable to use alkylene glycol as a raw material for the polyester to be produced in the production of the polycondensation catalyst of the present invention. Specifically, for example, when the polyester to be produced is polyethylene terephthalate, ethylene glycol is preferably used.
(Alkaline earth metal compounds)
Examples of the alkaline earth metal compound include oxides such as magnesium and calcium, inorganic compounds such as hydroxides and carbonates, and organic acid salts. Magnesium compounds are preferred from the viewpoint of catalytic activity.

  Examples of the magnesium compound include inorganic compounds such as magnesium oxide, magnesium hydroxide, and magnesium carbonate, magnesium salts of organic acids such as magnesium acetate, magnesium lactate, and magnesium stearate, and magnesium alkoxide. Of these, magnesium acetate or a hydrate thereof is preferable because of its high solubility and easy preparation of a liquid catalyst.

(Acid phosphate compound)
As the acidic phosphate compound, those having the following structural formula are preferable.

（上記式中、Ｒ、Ｒ'、Ｒ"は炭素数１以上６以下のアルキル基、シクロヘキシル基、またはアリール基を示す）

(In the above formula, R, R ′, and R ″ represent an alkyl group, a cyclohexyl group, or an aryl group having 1 to 6 carbon atoms)

  Specific examples thereof include methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, etc. Among them, ethyl acid phosphate and / or butyl acid phosphate are preferable. The acidic phosphate compound includes a monoester form and a diester form, and a mixture thereof is particularly preferable. The R, R ′ and R ″ of the monoester and diester are preferably the same. The mixing weight ratio of the monoester and diester is preferably in the range of 80:20 to 20:80, more preferably. Is in the range of 30:70 to 70:30, particularly preferably 40:60 to 60:40.

(Titanium compound)
As titanium compounds, tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, acetyl-tri-i-propyl titanate, etc. And tetraalkyl titanates such as tetra-i-propyl titanate and tetra-n-butyl titanate, and titanium oxalate are particularly preferred from the viewpoint of catalytic activity. Tetraalkyl titanates are preferred. Of the tetraalkyl titanates, tetra-n-butyl titanate is particularly preferred.

(Mixing ratio)
The liquid polyester polycondensation catalyst of the present invention contains titanium, alkaline earth metal, and phosphorus, but the content of titanium in the liquid catalyst is usually 0.01% by weight as the titanium atom, preferably 0.02% by weight. The upper limit is usually 2.0% by weight, preferably 1.5% by weight. If it is less than the lower limit, the active component in the catalyst solution is small and a large amount of catalyst solution is required. On the other hand, when the upper limit concentration is exceeded, it tends to be difficult to obtain a uniform solution.
The molar ratio of titanium, alkaline earth metal (M) and phosphorus in the liquid polyester polycondensation catalyst of the present invention is preferably in the range of the following formulas ( 2 ) and ( 3 ).

0.1 ≦ M / P ≦ 3 ( 2 )
0.1 ≦ Ti / P ≦ 5 ( 3 )
The preferable lower limit of Mg / P (molar ratio) is 0.2, particularly preferably 0.5, and the preferable upper limit is 2, particularly preferably 1.5. Further, the preferable lower limit of Ti / P (molar ratio) is 0.2, particularly preferably 0.3, and the preferable upper limit is 3, particularly preferably 1.5.
When M / P (molar ratio) exceeds 3, the titanium compound and the alkaline earth metal compound mixed in step (ii) described later tend to react with each other to easily generate an insoluble compound. Moreover, when M / P is less than 0.1, the polycondensation activity tends to decrease.
When Ti / P (molar ratio) exceeds 5, an insoluble gel composition composed of titanium and phosphorus is easily generated in the liquid catalyst. When Ti / P is less than 0.1, the catalyst activity tends to decrease.
When M / P (molar ratio) and Ti / P (molar ratio) satisfy the above ranges, a liquid polyester catalyst excellent in long-term storage stability and reactivity can be obtained more reliably.

(Manufacturing)
The liquid polyester polycondensation catalyst of the present invention comprises (i) a step of previously mixing an alcohol, an alkaline earth metal compound, and an acidic phosphate ester compound, and (ii) a mixture obtained in step (i). Furthermore, it can manufacture by the process of mixing a titanium compound.

In step (i), specifically, for example, in a preparation tank equipped with a raw material inlet, a stirrer, etc.
Examples include a method in which an alcohol such as an alkylene glycol, an alkaline earth metal compound, and an acidic phosphate compound are added in a proportion such that the molar ratio of the alkaline earth metal and phosphorus is in the range of the above formula ( 2 ), and the mixture is stirred. . In addition, as described above, the proportion of alcohol used is usually such that the molar ratio of titanium to phosphorus in the liquid polyester polycondensation catalyst of the present invention falls within the range of the above formula ( 3 ), and the titanium content is titanium. The ratio of the concentration of 0.01% to 2% by weight as atoms is selected. However, the component concentration may be controlled by using a predetermined amount or more of alcohol and distilling it after preparing the liquid catalyst as described later.
The above raw materials are mixed under mild conditions. For example, mixing at 5 to 60 minutes under normal pressure at 10 to 80 ° C., preferably 20 to 50 ° C., usually results in a uniform transparent mixed solution. Step (ii)
Usually, after visually confirming that the mixed liquid in step (i) has become transparent, a titanium compound is added and stirred. In the step (ii), the same conditions (temperature, pressure, time) as in the step (i) can be adopted, whereby a uniform and transparent liquid polyester polycondensation catalyst can be obtained.
Also, for example, after preparing a polycondensation catalyst using a monohydric alcohol in steps (i) and (ii), the monohydric alcohol is once distilled off, and alkylene glycol is added again to form a liquid polyester polycondensation catalyst. You can also get

Production of the catalyst of the present invention and storage of the polycondensation catalyst can be carried out in an air atmosphere or an inert gas atmosphere such as nitrogen gas. In the case of long-term storage for a few months or more, an inert gas atmosphere is preferable.
Further, as will be described later, the liquid polyester polycondensation catalyst of the present invention preferably contains the amount of water described below, but in addition to the case where water is inevitably mixed from the raw material used, Even if it mixes water, you may mix water with the liquid mixture of each process.

According to the above method, a liquid polyester polycondensation catalyst containing titanium, alkaline earth metal, and phosphorus can be produced in a short time without heating to a high temperature. Unnecessary components may be removed by distillation under reduced pressure. For example, removal of excess water, adjustment of the concentration of each metal element in the liquid catalyst, acetic acid produced as a by-product when magnesium acetate is used, removal of n-butanol when tetra-n-butyl titanate is used, etc. it can.

(Liquid polyester polycondensation catalyst)
The pH of the liquid polyester polycondensation catalyst of the present invention thus obtained is usually 3 or more and 7 or less, preferably 4 or more and 6.5 or less, and more preferably 5.5 or more and 6 or less. If the pH exceeds 7, the metal tends to precipitate. If the pH is less than 3, the polycondensation catalyst may change into a gel state over time, and the apparatus may be corroded.
The liquid polyester polycondensation catalyst of the invention is preferably a homogeneous transparent solution at room temperature. In the present invention, the term “transparent” means having transparency to the extent that it can be visually recognized, and preferably has a turbidity of 5% or less at an optical path length of 10 mm.

The liquid polyester polycondensation catalyst of the present invention preferably contains a small amount of water. The water content (weight concentration) with respect to the entire liquid polyester polycondensation catalyst is preferably 10% or less, more preferably 5% or less, and particularly preferably 1.5% or less. Moreover, 0.01% or more is preferable, More preferably, it is 0.1% or more, Especially 0.5% or more is preferable. If the water content exceeds the above upper limit, the titanium compound reacts with water and gels, and it tends to be difficult to obtain a uniform solution. On the other hand, if it is less than 0.01%, the resulting liquid polyester polycondensation catalyst will tend to be clouded when precipitated for a long period of time.
Water may be derived from the catalyst raw material (for example, a hydrate is used as the alkaline earth metal compound), and an appropriate amount may be added to the alkylene glycol used in the production of the catalyst. Medium may be added after preparation. Therefore, in the case where a hydrate of magnesium compound is used or the like and water is contained in the liquid catalyst derived from the catalyst raw material, the water concentration is within the above range in consideration of moisture from the hydrate. Is preferably adjusted.

  Although it is not clear why the liquid polyester polycondensation catalyst of the present invention becomes a homogeneous catalyst solution that is stable for a long time, both compounds react by mixing an acidic phosphate compound and an alkaline earth metal compound in advance, By forming a relatively stable salt and then mixing the titanium compound, the titanium / magnesium does not react directly, and the titanium compound and the phosphorus compound maintain an appropriate interaction. It is presumed that a ternary complex complex of a similar metal / phosphorus is formed and is stabilized in an alcohol solvent.

<Method for producing polyester resin>
As a method for producing the polyester resin of the present invention, a conventional method for producing a polyester resin can be basically used except that the liquid polyester polycondensation catalyst of the present invention is used. As an example of a conventional method for producing a polyester resin, a case where the polyester resin is polyethylene terephthalate will be described as an example.

  A dicarboxylic acid component containing terephthalic acid or its ester-forming derivative as a main component and a diol component containing ethylene glycol as a main component are esterified in an esterification reaction tank, or esterified in the presence of a transesterification catalyst. After the exchange reaction, the obtained esterification reaction product or the polyester low molecular weight product, which is the ester exchange reaction product, is transferred to a polycondensation tank and subjected to melt polycondensation in the presence of a polycondensation catalyst. And solid phase polycondensation. Moreover, this manufacturing method may be a continuous type or a batch type, and is not particularly limited.

  The raw material used is preferably such that the proportion of terephthalic acid or its ester-forming derivative in the dicarboxylic acid component is 90 mol% or more, more preferably 95 mol% or more, particularly 99 mol% or more, and the diol component It is preferable that the proportion of ethylene glycol in the total be 90 mol% or more, further 95 mol% or more, and particularly 97 mol% or more. If the proportion of terephthalic acid or its ester-forming derivative in the dicarboxylic acid component and the proportion of ethylene glycol in the diol component are less than the above ranges, the mechanical strength, gas barrier property, and heat resistance of the resulting polyester molded article are There is a tendency to decrease.

  Examples of ester-forming derivatives of terephthalic acid include esters having an alkyl group having about 1 to 4 carbon atoms, halides, and the like. Examples of dicarboxylic acid components other than terephthalic acid or ester-forming derivatives thereof include, for example, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalic acid, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4 , 4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and other aromatics Alicyclic dicarboxylic acids such as dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid Aliphatic diacids such as acids Carboxylic acid, and esters having an alkyl group having about 1 to 4 of carbon, and halide, one or two or more may be used as a copolymerization component and the like.

  Examples of the diol component other than ethylene glycol include diethylene glycol, and the proportion of the diethylene glycol in the diol component is preferably 3 mol% or less including the amount of by-product generated in the reaction system. More preferably, it is at least mol% and at most 2.5 mol%. Examples of other diol components include 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, polyethylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2,5 -Alicyclic diols such as norbornane dimethylol, and xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4 ' aromatic diols such as β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and 2,2-bis (4′-hydroxyphenyl) propane One or two or more of ethylene oxide adduct or propylene oxide adduct may be used as a copolymerization component.

  Furthermore, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, heneicosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, benzoic acid Monofunctional components such as acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, One or two or more multifunctional components such as pentaerythritol and the like may be used as the copolymerization component.

  In the present invention, the dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component, the diol component containing ethylene glycol as a main component, and the copolymerization component used as necessary are esterified. Alternatively, in the transesterification reaction, the molar ratio of the diol component to the dicarboxylic acid component is mixed and prepared in the range of usually lower limit of 1.02, preferably 1.03 and upper limit of usually 2.0, preferably 1.7. It is common.

  In the case of a transesterification reaction, it is generally necessary to use a transesterification catalyst, and since it is necessary to use a large amount of the catalyst, the production method of polyester in the present invention uses dicarboxylic acid as a raw material. A method of producing via an esterification reaction is preferred.

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

As reaction conditions in the esterification reaction, when a single esterification reaction tank is used, the temperature is usually about 200 to 280 ° C., and the relative pressure to atmospheric pressure is usually about 0 to 400 kPa (0 to 4 kg / cm ² G). In general, the reaction time is about 1 to 10 hours under stirring. When a plurality of esterification reactors are used, the lower limit of the reaction temperature in the first stage esterification reactor is usually 240 ° C., preferably 245 ° C., and the upper limit is usually 270 ° C., preferably 265 ° C., reaction pressure. Is a relative pressure with respect to atmospheric pressure, the lower limit is usually 5 kPa (0.05 kg / cm ² G), preferably 10 kPa (0.1 kg / cm ² G), and the upper limit is usually 300 kPa (3 kg / cm ² G), preferably 200 kPa ( 2 kg / cm ² G), the reaction temperature in the final stage is usually 250 ° C., preferably 255 ° C., the upper limit is usually 280 ° C., preferably 275 ° C., and the reaction pressure is usually 0 to 150 kPa relative to atmospheric pressure. (0 to 1.5 kg / cm ² G), preferably 0 to 130 kPa (0 to 1.3 kg / cm ² G) is usually used.

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

  Examples of melt polycondensation include a single melt polycondensation tank or a plurality of melt polycondensation tanks connected in series, for example, a fully-mixed reactor in which the first stage is equipped with a stirring blade, Examples include a method in which the ethylene glycol produced is distilled out of the system under reduced pressure using a multistage reaction apparatus comprising a horizontal plug flow reactor in which the second and third stages are equipped with stirring blades. .

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

  In general, the phosphorus compound is often added before the start of the polycondensation reaction. However, when using the catalyst of the present invention containing the phosphorus compound in advance, it is not particularly necessary to add the phosphorus compound.

  The addition of the liquid polyester polycondensation catalyst of the present invention to the reaction system may be any of the mixing / preparation stage of the dicarboxylic acid component and the diol component, any stage of the esterification reaction, or the initial stage of melt polycondensation. It may be. However, in order to effectively develop the effect of the present invention of producing a polyester excellent in color tone and transparency at a high reaction rate, addition of the liquid polyester polycondensation catalyst of the present invention to the reaction system is carried out by esterification. It is preferable to carry out after the stage where the rate becomes 90% or more, and examples of specific processes include the final stage esterification reaction tank in the multistage reaction apparatus, or the transfer stage from the esterification tank to the melt polycondensation process. It is preferable to add to the esterification reaction product, and it is more preferable to add to the esterification reaction product in the transfer stage from the esterification tank to the melt polycondensation process.

  The intrinsic viscosity ([η1]) of the polyester obtained by the melt polycondensation is a value measured at 30 ° C. using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent, and the lower limit is usually 0.35 dL / g, preferably 0.50 dL / g, and the upper limit is usually 0.75 dL / g, preferably 0.65 dL / g. If the intrinsic viscosity ([η1]) is less than the above range, the operability may be deteriorated when it is extracted from the polycondensation tank described later. On the other hand, if it exceeds the above range, the acetaldehyde content in the resulting polyester may be reduced. It can be difficult.

The polyester obtained by the melt polycondensation is usually extracted in a strand form from an outlet provided at the bottom of the polycondensation tank, and is cooled with water or after water cooling, and then cut with a cutter to form pellets, chips, etc. Although it is set as a granular body, the granular body after this melt polycondensation can further be solid-phase polycondensed as needed. The solid phase polycondensation method can be performed by a conventionally known method, for example, the method described in paragraphs [0057] to [0065] of JP-A No. 2004-292803.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
In the following examples, the pH and water content of the liquid polyester polycondensation catalyst were measured as follows.
Further, the intrinsic viscosity [η], color tone, terminal carboxyl group content, diethylene glycol unit content, cyclic trimer (CT) content, and polycondensation reaction rate of the obtained polyester were measured as follows.
<PH measurement>
Using an automatic titrator (AUT-501 type) manufactured by Toa DKK, the pH electrode was immersed in a liquid catalyst and measured in the atmosphere.
<Moisture measurement>
Measurement was performed based on the principle of Karl Fischer reaction using a moisture measuring device CV-06 manufactured by Mitsubishi Chemical Corporation.

<Intrinsic viscosity [η]>
In the case of a pellet-shaped resin, 0.25 g of a resin sample obtained by freeze-pulverizing a pellet, and in the case of a molded product, 0.25 g of a resin sample obtained by cutting into a size similar to that of a pellet and then freeze-ground. / Tetrachloroethane (weight ratio 1/1) as a solvent, concentration (c) is 1.0 g / dL, and in the case of molten polycondensation resin and molded body, 110 ° C. for 30 minutes, solid phase polycondensation In the case of resin, after dissolving by holding at 120 ° C. for 30 minutes, the relative viscosity (η rel) with the stock solution is measured at 30 ° C. using an Ubbelohde capillary viscosity tube, and this relative viscosity (η rel) − The ratio (ηsp / c) between the specific viscosity (ηsp) and the concentration (c) obtained from 1 was obtained, and the concentration (c) was also set to 0.5 g / dL, 0.2 g / dL, and 0.1 g / dL. Also find the ratio (ηsp / c) From al value was determined as the ratio of time extrapolated concentration (c) to 0 (ηsp / c) an intrinsic viscosity [η] (dL / g).

<Color tone>
The polyester chip obtained by the polycondensation reaction is filled in a cylindrical powder measurement cell having an inner diameter of 30 mm and a depth of 12 mm, and a colorimetric color difference meter ZE-2000 (Nippon Denshoku Industries Co., Ltd.) is used. A simple average of values obtained by measuring the color b value by the color coordinate of the color difference formula of Hunter in the Lab display system described in Reference Example 1 of JIS Z8730 by rotating the measurement cell by 90 degrees by the reflection method. Obtained as a value.

<Amount of terminal carboxyl group>
After pulverizing the polyester chip, the sample was dried at 140 ° C. for 15 minutes in a hot air dryer, cooled to room temperature in a desiccator, 0.1 g was accurately weighed and collected in a test tube, and 3 mL of benzyl alcohol was added. The solution was dissolved at 195 ° C. for 3 minutes while blowing dry nitrogen gas, and then 5 mL of chloroform was gradually added and cooled to room temperature. One to two drops of phenol red indicator were added to this solution, and titrated with a 0.1N sodium hydroxide benzyl alcohol solution while stirring while blowing dry nitrogen gas, and the procedure was terminated when the color changed from yellow to red. Further, as a blank, the same operation was carried out without a polyester resin sample, and the acid value was calculated by the following formula ( 4 ).

Acid value = (mol / ton) = (A−B) × 0.1 × f / W ( 4 )
[Where A is the amount of 0.1N sodium hydroxide in benzyl alcohol solution required for titration (μL), and B is 0.1N sodium hydroxide in benzyl alcohol solution required for titration with a blank. The amount (μL), W is the amount (g) of the polyester resin sample, and f is the titer of 0.1N sodium hydroxide in benzyl alcohol. ]
The titer (f) of 0.1N sodium hydroxide in benzyl alcohol solution was obtained by taking 5 mL of methanol in a test tube and adding 1 to 2 drops of phenol red ethanol solution as an indicator. Titrate with 0.4 mL of 1N sodium hydroxide in benzyl alcohol to the color change point, then add 0.2 mL of 0.1 N hydrochloric acid solution of known titer as a standard solution and add it again. Titrate to discoloration with sodium benzyl alcohol solution. (The above operation was performed while blowing dry nitrogen gas.) The titer (f) was calculated by the following equation ( 5 ).

Titer (f) = 0.1N hydrochloric acid aqueous solution titer x 0.1N hydrochloric acid aqueous solution collection amount (μL)
/ ΜL of 0.1N sodium hydroxide in benzyl alcohol solution
( 5 )
<Content of diethylene glycol unit>
A polyester chip was dissolved in deuterated trifluoroacetic acid at room temperature to obtain a 3 wt% solution. Using a JNM-EX270 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd., ¹ H-NMR was measured using trimethylsilyl chloride (TMS) as a standard substance, and each peak was assigned. The peak derived from the diol component was extracted from the assigned peak, and the diethylene glycol amount (mol%) in the diol component was calculated from the integration ratio.

<Cyclic trimer (CT) content>
After freeze-grinding the polyester chips after solid-phase polycondensation, weigh precisely 200 mg of the resin sample,
It was dissolved in 2 mL of a mixed solution of chloroform / hexafluoroisopropanol (volume ratio 3/2), and further diluted by adding 20 mL of chloroform. 10 mL of methanol was added thereto to precipitate a sample, and then filtered to obtain a filtrate. After the filtrate was evaporated to dryness, the residue was dissolved in 25 mL of dimethylformamide. The amount of cyclic trimer (cyclotriene terephthalate) in this solution was quantified by LC-10A type liquid chromatography manufactured by Shimadzu Corporation and expressed in ppm by weight per resin.

  When the cyclic trimer content is large, the mold becomes dirty due to adhesion of the cyclic trimer to the molding die when this resin is molded, and it becomes difficult to obtain a good molded product.

<Polycondensation reaction rate>
The melt polycondensation rate Km is determined by the following formula ( 6 ).

Km = ln (Mn ′ / Mn) / hour (minute) × 10 ² ... ( 6 )
In the formula ( 6 ), Mn ′ is the number average molecular weight of the polyester calculated from the intrinsic viscosity [η] (dL / g) of the polyester after the melt polycondensation reaction, and Mn is the intrinsic viscosity of the oligomer before the polycondensation reaction. It is the number average molecular weight of the oligomer calculated from the above. Time (minutes) is the polycondensation reaction time after the start of decompression.

Similarly, the solid phase polycondensation rate Ks is obtained by the following formula ( 7 ).

Ks = ln (Mn ″ / Mn ′) / hour (minutes) × 10 ⁴ ( 7 )
In the formula ( 7 ), Mn ″ is the number average molecular weight of the polyester calculated from the intrinsic viscosity [η] (dL / g) of the polyester after the solid phase polycondensation reaction.

In addition, molecular weight Mn and Mn 'are calculated | required by following formula ( 8 ).

Molecular weight (Mn or Mn ′) = (Intrinsic viscosity [η] /0.00021) ^{(1 / 0.82)} ( 8 )

Example 1 Production of Liquid Polyester Polycondensation Catalyst
Ethylene glycol 500 g, magnesium acetate tetrahydrate 23.3 g, ethyl acid phosphate 11.9 g (trade name: JP-502, manufactured by Johoku Chemical Co., Ltd., monoester and diester (M / P (molar ratio) = 1.3) was mixed and stirred at normal pressure and room temperature (23 ° C.) to obtain a homogeneous transparent solution after 10 minutes. . Next, 12.5 g of tetra-n-butyl titanate was added over 2 minutes (Ti / P (molar ratio) = 0.43, titanium content 0.3% by weight), and stirring was further performed. Immediately after the addition of tetra-n-butyl titanate, the solution once became cloudy, but after 5 minutes, a uniform transparent polyester polycondensation catalyst solution was obtained. The obtained catalyst solution was transferred to a sample bottle and stored in a refrigerator (5 ° C.), room temperature (23 to 25 ° C.), and a heat storage box (50 to 60 ° C.) in a sealed state, and the state was observed. Uniform transparency was maintained under any condition for 3 months.
The liquid polyester polycondensation catalyst obtained above had a pH of 5.5 and a water content of 1.4% by weight.

(Example 2 / Production of liquid polyester polycondensation catalyst)
A catalyst solution was obtained in the same manner as in Example 1 except that 17.9 g of dibutyl acid phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of ethyl acid phosphate (M / P (molar ratio) = 1). .3, Ti / P (molar ratio) = 0.43, titanium content 0.3 wt%).

The obtained catalyst solution was transferred to a sample bottle and stored in a refrigerator (5 ° C.), room temperature (23 to 25 ° C.), and a heat storage box (50 to 60 ° C.), and the state was observed. Uniform transparency was maintained under any condition for 3 months.
The liquid polyester polycondensation catalyst obtained above had a pH of 5.5 and a water content of 1.4% by weight.

(Example 3 / Production of liquid polyester polycondensation catalyst)
A catalyst solution was obtained in the same manner as in Example 1 except that the amount of ethyl acid phosphate used was 4.8 g (Mg / P (molar ratio) = 3.2) (Ti / P (molar ratio)) = 1.1, titanium content 0.3 wt%). When the obtained catalyst solution was transferred to a sample bottle and allowed to stand at room temperature (23 to 25 ° C.) for one month, some precipitates were formed.
The liquid polyester polycondensation catalyst obtained above had a pH of 5.9 and a water content of 1.4% by weight.

(Comparative Example 1 / Production of catalyst)
A catalyst was produced by mixing the titanium compound, the magnesium compound, and the acidic phosphate compound in the same order as described in Patent Document 3.
That is, 500 g of ethylene glycol was charged into a 1 L glass eggplant type flask equipped with a stirrer, in which 23.3 g of magnesium acetate tetrahydrate was suspended, and then 12.5 g of tetra-n-butyl titanate was added. Then, mixing and stirring were performed at room temperature (23 ° C.). After 60 minutes, a situation where a large amount of white slurry was suspended was observed. Subsequently, 11.9 g of ethyl acid phosphate was added (M / P (molar ratio) = 1.3, Ti / P (molar ratio) = 0.43, titanium content 0.3% by weight), and stirring was continued all day and night. Although continued, the slurry did not dissolve. After a few days, the slurry was completely separated into a white precipitate and a clear solvent. The precipitate was separated by filtration, dried under reduced pressure, subjected to wet decomposition with sulfuric acid and hydrogen peroxide, and then subjected to ICP metal analysis with an ICP-AES apparatus (JY-138U type manufactured by JOBIN YVON), mainly titanium and magnesium. Was included.

(Comparative Example 2 / Manufacture of catalyst)
Into a 1 L glass eggplant-shaped flask with a stirrer was charged 500 g of ethylene glycol,
Among them, 23.3 g of magnesium acetate tetrahydrate, 11.9 g of ethyl acid phosphate and 12.5 g of tetra-n-butyl titanate were added almost simultaneously (M / P (molar ratio) = 1.3, Mixing and stirring were performed at Ti / P (molar ratio) = 0.43, titanium content 0.3% by weight) and room temperature (23 ° C.). After 60 minutes, it became cloudy, and a few precipitates were observed after several days. As in Comparative Example 1, as a result of ICP metal analysis of the precipitate, it contained mainly titanium and magnesium.

(Comparative Example 3 / Production of catalyst)
Into a 1 L glass eggplant-shaped flask equipped with a stirrer was charged 500 g of ethylene glycol, 11.9 g of the above ethyl acid phosphate was added, and 12.5 g of tetra-n-butyl titanate was added to the homogeneous solution. C.) and mixing and stirring were performed. After 60 minutes, a large amount of white precipitate was observed. Next, even when 23.3 g of magnesium acetate tetrahydrate was added, a homogeneous solution was not obtained (M / P (molar ratio) = 1.3, Ti / P (molar ratio) = 0.43, titanium). Content 0.3 wt%). As in Comparative Example 1, as a result of ICP metal analysis of the precipitate, it contained mainly titanium and phosphorus. Further, the produced precipitate was yellowed after 30 days.

(Comparative Example 4 / Production of catalyst)
In a 1 L glass eggplant-shaped flask equipped with a stirrer, 500 g of ethylene glycol and 23.3 g of magnesium acetate tetrahydrate were charged, mixed and stirred, and after 30 minutes, a homogeneous transparent liquid was obtained. Next, 11.9 g of the above ethyl acid phosphate and 12.5 g of tetra-n-butyl titanate were simultaneously added thereto (M / P (molar ratio) = 1.3, Ti / P (molar ratio) = 0). .43, titanium content 0.3 wt%). Furthermore, mixing and stirring were performed at room temperature (23 ° C.). After 60 minutes, cloudiness was observed. Next, this catalyst solution was heated and refluxed at an oil bath temperature of 100 ° C. for 5 hours, but no appearance of white turbidity was observed. After standing for 1 day, white precipitate was confirmed, and as a result of ICP metal analysis in the same manner as in Comparative Example 1, this precipitate contained titanium, magnesium and phosphorus.

(Comparative Example 5 / Production of catalyst)
Into a 2-L three-necked flask with a stirrer, 919 g of ethylene glycol and 80 g of trimellitic anhydride were mixed and stirred, and 71 g of tetra-n-butyl titanate was added over 5 minutes to contain a transparent titanium compound. An ethylene glycol solution was obtained (this is referred to as solution A).

  To another 2 L three-necked flask equipped with a stirrer, 400 g of ethylene glycol and 28.3 g of magnesium acetate tetrahydrate were added and heated to 100 ° C. in an oil bath with stirring to obtain a homogeneous solution (this (Solution B).

  Further, 272 g of ethylene glycol was placed in a 2 L three-necked flask equipped with a stirrer and heated to 160 ° C. while stirring. When the temperature reached 160 ° C., 18.2 g of trimethyl phosphate was added and dissolved by heating, mixing and stirring to obtain a transparent solution (this is referred to as Solution C).

  310 g of the previously prepared solution A was added over 5 minutes to the above-mentioned solution B controlled to 100 ° C. under stirring, and the mixture was held at 100 ° C. for 1 hour with stirring. A mixed solution was prepared. Further, the whole amount of the above solution C was added thereto, and then stirred and held at a temperature of 100 ° C. for 1 hour.

The catalyst solution thus prepared (M / P (molar ratio) = 1.0, Ti / P (molar ratio) = 0.5, titanium content 0.3% by weight) was cooled to room temperature and stored. As a result of evaluation, although it was transparent for several hours after cooling, white turbidity was clearly observed after one day, and a large amount of precipitate was observed after one week.
Table 1 summarizes the outlines of the catalyst production methods of Examples 1 to 3 and Comparative Examples 1 to 5 and the results of the obtained catalysts.

Example 4 Production of Polyester
The polycondensation reaction was carried out using the uniform liquid polyester polycondensation catalyst containing titanium, magnesium and phosphorus obtained in Example 1.

(Manufacture of raw material oligomers)
2012 kg (10.4 × 10 ³ mol) of dimethyl terephthalate and ethylene glycol 1
286 kg (20.7 × 10 ³ ) was supplied to the esterification reaction tank and dissolved, and then calcium acetate dissolved in ethylene glycol was 0.20 kg as calcium atoms (based on the product obtained by the transesterification reaction). 100 ppm), and the transesterification reaction was carried out while distilling off the produced methanol while maintaining the temperature at 220 ° C. After completion of the transesterification reaction, 1721 kg (10.4 × 10 ³ ) of terephthalic acid and 772 kg (12.4 × 10 ³ mol) of ethylene glycol were stirred and mixed in this esterification reaction tank. The obtained slurry was continuously supplied over 3 hours, an esterification reaction was performed at about 250 ° C. under normal pressure, and about 4% after the start of transfer, about 50% of the reaction solution was withdrawn into the polycondensation reaction tank. .

  The esterification reaction tank was supplied with a slurry of terephthalic acid and ethylene glycol obtained in the same manner as described above to conduct an esterification reaction, and a step of extracting about 50% of the reaction liquid into the polycondensation reaction tank was measured. The concentration of calcium acetate in the esterification reaction solution was adjusted to 0.5 ppm or less by repeating 10 times.

  In this way, an esterification product (oligomer) of terephthalic acid and ethylene glycol substantially containing no transesterification catalyst component was produced. The esterification product was extracted during transfer from the esterification reaction tank to the polycondensation reaction tank, and cooled and solidified in the air to obtain a raw material oligomer used in the following examples. The esterification reaction rate of this raw material oligomer was 96%.

  The molar ratio of ethylene glycol used for the production of this raw material oligomer to terephthalic acid was finally 1.2, and the number average molecular weight (Mn) of the obtained raw material oligomer was 2280.

(Polycondensation reaction)
104 g of the raw material oligomer was transferred to a polycondensation reactor equipped with a stirrer with a torque meter and the system was replaced with nitrogen, and then the oligomer was dissolved in an oil bath (constant at 260 ° C.). Hereinafter, the time is expressed by setting the oligomer dissolution start time as 0 hours.

After confirming that the oligomer was completely dissolved after 60 minutes, stirring was started at 50 rpm, and the liquid polyester polycondensation reaction catalyst prepared in Example 1 was diluted 26 times with ethylene glycol. After 70 minutes, 3 mL was added. The contents of titanium, magnesium and phosphorus in the resulting polyester resin are 4, 6, and 6 ppm by weight, respectively. Depressurization was started after 80 minutes, and after 140 minutes, the pressure was reduced to 2.7 × 10 ⁻⁴ MPa. The depressurization operation was performed so that the logarithmic value of the pressure was inversely proportional to the time. The polycondensation temperature is increased from 260 ° C. to 280 ° C. at a constant rate during 80 to 160 minutes, and the melt weight is adjusted so that the intrinsic viscosity falls within the range of 0.50 to 0.60 (dL / g). A condensation reaction was performed. The polycondensation start time was set as the pressure reduction start time.

After completion of the melt polycondensation (melt polycondensation time 163 minutes), stirring was stopped, the pressure was returned to normal pressure with nitrogen, and the polycondensation reactor was taken out of the oil bath. After removing the polycondensation reactor from the oil bath, quickly evacuate the outlet of the reactor, extract the polyester by slightly pressurizing the system with nitrogen, and cool and solidify the polyester to obtain a strand-like polyester. It was. The obtained polyester was cut into chips of about 0.02 (g / grain). The obtained polyester resin had an intrinsic viscosity of 0.520 dL / g and a color b value of 7.0.

  2 g of the obtained chip-like polyester resin was arranged in an aluminum foil cup (bottom diameter 4.5 cm, top diameter: 7.0 cm, depth: 5.0 cm) so that the chips do not overlap each other, and the internal temperature was set to 60 ° C. Installed in the center of the inert oven (I / O DN4101, manufactured by Yamato Scientific Co., Ltd.). Under a nitrogen flow of 30 L / h, the temperature was raised from 60 ° C. to 160 ° C. in 30 minutes, and drying and crystallization were performed at 160 ° C. for 2 hours. Then, it heated up to 210 degreeC over 30 minutes, and solid-phase polycondensation was performed at 210 degreeC for 10 hours. After the solid phase polycondensation was completed, the temperature was lowered to 60 ° C. over 30 minutes, and then the chip was recovered.

(Comparative Example 6 / Production of polyester)
In Example 4, instead of the liquid polycondensation catalyst, the same procedure as in Example 4 was used except that the white precipitate mainly containing titanium and magnesium obtained in Comparative Example 1 and the ethylene glycol slurry containing ethyl acid phosphate were used. A polycondensation reaction was performed. A polyester resin having an intrinsic viscosity of 0.558 dL / g and a color b value of 8.6 was obtained at a melt polycondensation time of 340 minutes.

Solid phase polycondensation was carried out for 10 hours in the same manner as in Example 4.
Table 2 summarizes the polymerization results of Example 4 and Comparative Example 6.

  As is apparent from the results in Table 2, the uniform liquid polyester polycondensation catalyst containing titanium, magnesium and phosphorus obtained by the method of the present invention has excellent polycondensation activity, and is used for melt polycondensation. It can be seen that the polyester obtained by the above has particularly good color tone, and that the polyester obtained by solid phase polycondensation is excellent in quality such as a small proportion of cyclic trimer.

Claims (8)

(I) a step of previously mixing an alcohol, an alkaline earth metal compound, and an acidic phosphate compound, and
  (ii) a step of further mixing a titanium compound with the mixed solution obtained in step (i),
  A method for producing a liquid polyester polycondensation catalyst containing titanium, an alkaline earth metal, and phosphorus, wherein the acidic phosphate compound is represented by the following general formula (1):

(In the above formula, R and R ′ are alkyl groups having 1 to 6 carbon atoms, cyclohexyl groups, or
Reel group is shown) The method for producing a polyester polycondensation catalyst according to claim 1, wherein the alcohol is alkylene glycol. The titanium content is in the range of 0.01 to 2% by weight as titanium atoms, and the molar ratio of alkaline earth metal (M) to phosphorus and the molar ratio of titanium to phosphorus are the following formulas (2) and (3 The method for producing a polyester polycondensation catalyst according to claim 1 or 2, wherein
0.1 ≦ M / P ≦ 3 (2)
0.1 ≦ Ti / P ≦ 5 (3)
(However, Ti, Mg, and P show the content (molar basis) in the catalyst for polyester polycondensation of titanium, alkaline earth metal, and phosphorus, respectively) The method for producing a polyester polycondensation catalyst according to any one of claims 1 to 3, comprising 0.01 to 10% by weight of water. The method for producing a polyester polycondensation catalyst according to any one of claims 1 to 4, wherein the alkaline earth metal compound is a magnesium compound . 6. The method for producing a polyester polycondensation catalyst according to claim 5, wherein the magnesium compound is a magnesium salt of an organic acid or a hydrate thereof . The method for producing a polyester polycondensation catalyst according to any one of claims 1 to 6, wherein the titanium compound is a tetraalkyl titanate . The manufacturing method of a polyester resin using the catalyst obtained by the manufacturing method of the catalyst for polyester polycondensation of any one of Claims 1-7.