JP2010195934A - Method for producing polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester reducing generation of foreign matter and dirt in a mold during molding due to a polymerization catalyst and a hue regulator, and obtaining a polyester excellent in thermostability and hue of a polymer and greatly improved in hue degradation during high-temperature melting in comparison with a conventional one. <P>SOLUTION: The method for producing a polyester includes esterification or transesterification followed by polycondensation in a polymerization reactor under reduced pressure. In the method, a titanium compound prepared as an alkylene glycol solution satisfying the following formulas (1) and (2), a hue regulator prepared as an alkylene glycol solution satisfying the following formulas (3) and (4) are added until a targeted polymerization degree of the polyester is attained, then a phosphorus compound is added from the initiation of reduction of pressure in a polymerization reactor until a targeted polymerization degree of the polyester is attained. (1) 0.1≤T/W<SB>T</SB>≤1.5; (2) 0.01≤W<SB>T</SB>≤1.0; (3) 0.01≤C/W<SB>C</SB>≤1.0; (4) 0.01≤W<SB>C</SB>≤1.0, wherein T is titanium atom concentration (wt.%) in a solution, W<SB>T</SB>is a water content (wt.%) in the solution, C is a hue regulator concentration (wt.%) in a solution, and W<SB>C</SB>is a water content (wt.%) in the solution. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for producing a polyester excellent in hue and thermal stability. More specifically, it reduces the occurrence of foreign matter due to the catalyst and hue modifier used during polymerization and mold contamination during molding, and has better polymer thermal stability and hue than conventional products, and hue when melted at high temperatures. The present invention relates to a method for producing polyester in which deterioration has been dramatically improved.

Polyester is used for various purposes because of its useful functionality, and is used for clothing, materials, and medical use, for example. Among them, polyethylene terephthalate is excellent in terms of versatility and practicality and is preferably used.
In general, polyethylene terephthalate is produced from terephthalic acid or an ester-forming derivative thereof and ethylene glycol. In a commercial process for producing a high molecular weight polymer, an antimony compound is widely used as a polycondensation catalyst. However, polymers containing antimony compounds have some undesirable properties as described below.
For example, when a polymer obtained using an antimony catalyst is melt-spun into a fiber, it is known that an antimony catalyst residue is deposited around the die hole. As this deposition progresses, it becomes a cause of defects in the filament, so that it needs to be removed in a timely manner. The deposition of the antimony catalyst residue is considered to be due to the antimony compound in the polymer being transformed in the vicinity of the die and partially vaporizing and dissipating, and then a component mainly composed of antimony remains in the die. In addition, the antimony catalyst residue in the polymer tends to be relatively large particles, and it becomes a foreign substance, causing an increase in the filtration pressure of the filter during molding, causing yarn breakage during spinning or film tearing during film formation, etc. It has undesirable characteristics and contributes to a decrease in operability.
In view of the above background, there is a demand for polyesters that do not contain antimony. Therefore, germanium compounds are known when the role of the polycondensation catalyst is required for compounds other than antimony compounds, but germanium compounds are difficult to use for general purposes because they have a small reserve and rare value.
In order to solve this problem, studies using a titanium compound as a polymerization catalyst have been actively conducted. Since the titanium compound has a higher catalytic activity than the antimony compound, the desired catalytic activity can be obtained with a small amount of addition, and generation of foreign particles and contamination of the base can be suppressed. However, when a titanium compound is used as a polycondensation catalyst, side reactions such as a thermal decomposition reaction and an oxidative decomposition reaction are promoted due to its high activity, resulting in a problem that the thermal stability is deteriorated and the polymer is colored yellow. It is not preferable that the polymer is yellowish, for example, when polyester is used as the fiber, since the commercial value of the fiber for clothing is impaired. In order to solve such a problem, studies have been widely made to improve the thermal stability and hue of a polymer by adding a phosphorus compound together with a titanium compound. This method suppresses the activity of titanium that is too high by the phosphorus compound, and improves the thermal stability and hue of the polymer. For example, in a polyester production method using a titanium compound as a catalyst, a method of adding a phosphite compound or a phosphate compound as a phosphorus compound (Patent Document 1), or a method of adding a phosphonite compound or a phosphonate compound as a phosphorus compound (Patent Document 2) ) Is specified. However, when these methods are used, a certain degree of improvement in the thermal stability of the polymer is certainly observed, but when a certain amount or more of a phosphorus compound is added, the polymerization activity of the titanium compound is excessively suppressed, and the target degree of polymerization is reached. The problem of not reaching or the polymerization reaction time being delayed resulted in deterioration of the hue of the polymer. Also, consider using a product obtained by reacting a titanium compound with a specific phosphorus compound, or an unreacted mixture or reaction product of a titanium compound and a specific phosphorus compound, respectively, as a catalyst for polyester production. (Patent Documents 3 to 5). In this study, the hue and thermal stability of the polyester can be improved to some extent, but the catalyst is deactivated when the amount of phosphorus compound added is still large, or the thermal stability when the amount of phosphorus compound is small. Was not enough. As described above, it was necessary to solve the contradictory problem of suppressing side reactions in order to improve thermal stability without impairing the polymerization reaction activity of the titanium compound.
In response to this problem, our research group found that thermal stability and hue can be improved without delay in polymerization time by adding a phosphorus compound in the latter half of the polycondensation reaction (Patent Document 6). According to this method, the general-purpose polyester can almost overcome the shortcomings of the titanium catalyst, but there are cases where it becomes a problem in the use of clothing that is severer in yellowness or the use of industrial materials that require high thermal stability. .
On the other hand, as an attempt to further improve the hue of the polyester, a polyester added with a dye is disclosed (Patent Document 7). However, a hue becomes dull due to a decrease in hue brightness, and foreign matter is generated depending on the addition conditions. Had the problem of.

JP-A-6-100680 (Claims) Japanese Patent Laying-Open No. 2005-15630 (Claims) JP 2005-290290 A (Claims) JP 2006-176625 A (Claims) JP 2008-63486 A (Claims) JP 2008-111088 A (Claims) JP 2007-284556 A (Claims)

The object of the present invention is to eliminate the above-mentioned conventional problems, that is, to reduce the occurrence of foreign matters due to the catalyst and the hue adjusting agent and the mold contamination during molding, and the thermal stability and hue of the polymer are greatly improved compared to the conventional products. It is providing the manufacturing method of polyester which was excellent in particular.

The object of the present invention is to esterify or transesterify a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, and then subject the polyester to a polycondensation reaction by reducing the pressure in the polymerization reactor. In the manufacturing method, the polyester is a target of a titanium compound adjusted as an alkylene glycol solution satisfying the formulas (1) and (2) and a hue adjusting agent adjusted as an alkylene glycol solution satisfying the formulas (3) and (4). A method for producing a polyester comprising adding a phosphorous compound until the degree of polymerization reaches a target degree of polymerization after the start of pressure reduction in the polymerization reactor .
(1) 0.1 ≦ T / W _T ≦ 1.5
(2) 0.01 ≦ W _T ≦ 1.0
(3) 0.01 ≦ C / W _C ≦ 1.0
(4) 0.01 ≦ W _C ≦ 1.0
[T: Titanium atom concentration (wt%) in the alkylene glycol preparation solution of the titanium compound, W _T : Water content (wt%) in the alkylene glycol preparation solution of the titanium compound, C: In the alkylene glycol preparation solution of the hue adjusting agent Hue adjusting agent concentration (wt%), W _C : Water content (wt%) in the alkylene glycol preparation solution of the hue adjusting agent]

According to the present invention, it is possible to obtain a polyester having greatly improved hue and thermal stability compared to conventional products. This polyester can solve problems such as deterioration of hue, dirt on the die, increased filtration pressure, and thread breakage in the production of molded articles for fibers, films and bottles.

The polyester production method of the present invention is a method in which dicarboxylic acid or an ester-forming derivative thereof and diol or an ester-forming derivative thereof are esterified or transesterified and then polycondensed.
Specific examples of the polyester obtained by such a production method include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, polyethylene. -1,2-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate and the like. The present invention is suitable for polyethylene terephthalate or polyester copolymers mainly containing ethylene terephthalate units, which are most commonly used.
In the polyester production method of the present invention, it is essential to use a titanium compound as a polycondensation catalyst. It does not specifically limit as a titanium compound, A titanium compound common as a polyester polycondensation catalyst, for example, titanium acetate, tetra-n-butoxy titanium, etc. are mentioned. More preferable as the titanium compound is a reaction between the compound represented by the general formula (I) or the compound represented by the general formula (I) and the aromatic polyvalent carboxylic acid or anhydride represented by the general formula (II). A product obtained by reacting a compound represented by general formula (I) with at least one phosphorus compound represented by general formula (III), (IV), or (V), general formula (I) A product obtained by reacting a compound represented by general formula (II) with an aromatic polycarboxylic acid or anhydride represented by general formula (II) and a phosphorus compound represented by general formula (III), (IV), or (V) It is to use a titanium complex compound having at least one selected from the group consisting of a product obtained by reacting at least one kind, a polyvalent carboxylic acid, a hydroxycarboxylic acid, and a nitrogen-containing carboxylic acid as a chelating agent.

[In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 10 carbon atoms or a phenyl group, p represents an integer of 1 to 4, and p Is 2, 3 or 4, 2, 3 or 4 R ² and R ³ may be different from each other. ]

[In formula (II), q represents the integer of 2-4. ]

[In the formula (III), r represents 1 or 2, s represents 0 or 1, provided that the sum of r and s is 1 or 2, and R ⁵ Represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms, and when r represents 2, two R ⁵ The groups may be the same or different from each other. In the formula (IV), u and v are integers of 1 to 3, t is an integer of 2 or more, and R ⁶ Represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms. In formula (V), R ⁷ And R ⁸ Represent the same or different alkyl groups having 1 to 4 carbon atoms, and X represents —CH 2 — or —CH (Y) —. ]
Examples of the titanium compound represented by the general formula (I) include tetraalkoxide titanium and / or tetraphenoxide titanium, and R ¹ ~ R ⁴ Is not particularly limited as long as is an alkyl group having 1 to 10 carbon atoms or a phenyl group, but tetraisopropoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetraethoxy titanium, or tetraphenoxy titanium are preferably used. It is done. In addition, the aromatic polyvalent carboxylic acid represented by the general formula (II) to be reacted with the titanium compound or the anhydride thereof includes phthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid, or an anhydride thereof. Preferably used. When the titanium compound represented by the general formula (I) and the aromatic polyvalent carboxylic acid represented by the general formula (II) or an anhydride thereof are reacted, the aromatic polyvalent carboxylic acid or the anhydride thereof is used as a solvent. What is necessary is just to melt | dissolve all or one part of a thing, drop a titanium compound to this, and to make it react for 30 minutes or more at the temperature of 0-200 degreeC. Moreover, what is necessary is just to add the remaining aromatic polyhydric carboxylic acid or its anhydride after dripping a titanium compound as needed. There is no limitation on the reaction molar ratio between the titanium compound (I) and the aromatic polyvalent carboxylic acid represented by the formula (II) or its anhydride. However, if the proportion of the titanium compound (I) is too high, the hue of the resulting polyester may be deteriorated or the softening point may be lowered. Conversely, if the proportion of the titanium compound (I) is too low, polycondensation may occur. The reaction may be difficult to proceed. For this reason, the reaction molar ratio of the titanium compound (I) and the aromatic polyvalent carboxylic acid represented by the formula (II) or its anhydride can be controlled within the range of 2/1 to 2/5. preferable. The reaction product obtained by this reaction may be used as a polycondensation catalyst, or may be further reacted with phosphorus compounds represented by the general formulas (III) to (V). In the case of reacting with a phosphorus compound, the reactive organism may be directly subjected to the reaction with the phosphorus compound, or it may be purified by recrystallization using a solvent comprising acetone, methyl alcohol and / or ethyl acetate. You may make it react with a post phosphorus compound.
The phosphorus compound represented by the general formula (III) is R ⁵ Represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms. Examples of the substituent include a carboxyl group, Including alkyl group, hydroxyl group and amino group. For example, phenylphosphonic acid, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, 2-carboxyl Phenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic acid, 2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxyphenylphosphonic acid, 2, 6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,3,4-tricarboxyphenylphosphonic acid, 2,3,5-tricarboxyphenylphosphonic Acid, 2, , 6-Tricarboxyphenylphosphonic acid, 2,4,5-tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, phenylphosphinic acid, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropyl Phosphinic acid, butylphosphinic acid, tolylphosphinic acid, xylylphosphinic acid, biphenylylphosphinic acid, diphenylphosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, ditolylphosphinic acid , Dixylylphosphinic acid, dibiphenylylphosphinic acid, naphthylphosphinic acid, anthrylphosphinic acid, 2-carboxyphenylphosphinic acid, 3-carboxyphenylphosphinic acid, -Carboxyphenylphosphinic acid, 2,3-dicarboxyphenylphosphinic acid, 2,4-dicarboxyphenylphosphinic acid, 2,5-dicarboxyphenylphosphinic acid, 2,6-dicarboxyphenylphosphinic acid, 3,4- Dicarboxyphenylphosphinic acid, 3,5-dicarboxyphenylphosphinic acid, 2,3,4-tricarboxyphenylphosphinic acid, 2,3,5-tricarboxyphenylphosphinic acid, 2,3,6-tricarboxyphenylphosphine Acid, 2,4,5-tricarboxyphenylphosphinic acid, 2,4,6-tricarboxyphenylphosphinic acid, bis (2-carboxyphenyl) phosphinic acid, bis (3-carboxyphenyl) phosphinic acid, bis (4- Carboxyphenyl) phosphinic acid, bis (2, 3-dicarboxylphenyl) phosphinic acid, bis (2,4-dicarboxyphenyl) phosphinic acid, bis (2,5-dicarboxyphenyl) phosphinic acid, bis (2,6-dicarboxylphenyl) phosphinic acid, bis ( 3,4-dicarboxyphenyl) phosphinic acid, bis (3,5-dicarboxyphenyl) phosphinic acid, bis (2,3,4-tricarboxyphenyl) phosphinic acid, bis (2,3,5-tricarboxyphenyl) ) Phosphinic acid, bis (2,3,6-tricarboxyphenyl) phosphinic acid, bis (2,4,5-tricarboxyphenyl) phosphinic acid, bis (2,4,6-tricarboxyphenyl) phosphinic acid, etc. Chosen from. When the titanium compound (I) and the phosphorus compound (III) are reacted, or when the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) is reacted with the phosphorus compound (III), For example, a phosphorus compound (III) and a solvent are mixed, and part or all of the phosphorus compound is dissolved in the solvent, and the titanium compound (I) is added dropwise to the mixture, and the reaction system is heated to a temperature of 0 ° C. to 200 ° C. For 10 minutes or longer, preferably 15 to 150 ° C. for 30 to 90 minutes. In this reaction, the reaction pressure is not particularly limited, and may be any of under pressure (0.1 to 0.5 MPa), normal pressure, or reduced pressure (0.001 to 0.1 MPa). Under normal pressure. At this time, the solvent used for the preparation of the phosphorus compound is not particularly limited as long as at least a part of the phosphorus compound (III) can be dissolved. For example, ethanol, ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene And a solvent comprising at least one selected from xylene and the like is preferably used. In particular, it is preferable to use, as a solvent, the same compound as the glycol component constituting the polyester to be finally obtained. In this preparation reaction, the mixing ratio of the titanium compound (I) and the phosphorus compound (III) in the reaction system, or the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) and the phosphorus compound ( The compounding ratio with III) is such that the reaction molar ratio mT: mPIII with respect to the molar amount (mPIII) of the titanium compound contained in the obtained reaction product to the molar amount of phosphorus atom (mPIII) of the phosphorus compound is 1: It is preferably set to be in a range of 1 to 1: 4. A more preferred reaction molar ratio is 1: 1 to 1: 3 for mT: mPIII.
The reaction product of titanium compound (I) and phosphorus compound (III), or the reaction product of titanium compound (I) and aromatic polycarboxylic acid compound (II) and the reaction product of phosphorus compound (III), After the reaction product is separated from the reaction system by means such as centrifugal sedimentation or filtration, it may be used as it is, or the separated reaction product may be used as a recrystallization agent, for example, It may be used after recrystallization and purification with acetone, methyl alcohol and / or water.
The phosphorus compound represented by the general formula (IV) is preferably a compound having a larger u. These phosphorus compounds may be used alone or in combination of two or more. In particular, ethylene glycol acid phosphate (corresponding to a compound of t = 2, u = 1, v = 1 or 2 in the formula (IV)) is preferred because it is industrially produced and easily available. When the titanium compound (I) and the phosphorus compound (IV) are reacted, or the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) is reacted with the phosphorus compound (IV), It can be produced by heating using alkylene glycol as a solvent. In this case, when the titanium compound (I) or the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) and the glycol solution of the phosphorus compound (IV) are mixed and heated, the titanium compound and the phosphorus compound are heated. React and the reaction product is obtained as a suspension in glycol. Examples of the glycol used here include ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, and cyclohexanedimethanol. As the alkylene glycol used as the solvent, it is preferable to use the same glycol as the raw material of the polyester produced using the catalyst produced thereafter. The reaction temperature is preferably at a temperature of 50 ° C. to 200 ° C., and the reaction time is usually 1 minute to 4 hours. It is preferable to complete. For example, when ethylene glycol is used as the alkylene glycol, 15 ° C. to 150 ° C. is preferable, and when hexamethylene glycol is used, 100 ° C. to 200 ° C. is a preferable range, and the reaction time is more preferably 30 minutes to 2 hours. If the reaction temperature is too high or the time is too long, the catalyst will deteriorate, which is not preferable. In this preparation reaction, the mixing ratio of the reaction product of titanium compound (I) and phosphorus compound (IV) in the reaction system, or the reaction product of titanium compound (I) and aromatic polycarboxylic acid compound (II) And the phosphorus compound (IV) are mixed in a molar ratio (mT) of titanium compound contained in the resulting reaction product to a molar ratio (mPIV) of phosphorus compound in terms of phosphorus atom (mPIV): It is preferable that mPIV is set to be in the range of 1: 1.5 to 1: 2.5. A more preferred reaction molar ratio is mT: mPIV of 1: 1.7 to 1: 2.3. On the other hand, if it is less than 1.5, many unreacted titanium compounds exist, and conversely, if it is 2.5 or more, many excessive unreacted phosphorus compounds exist.
Examples of the phosphorus compound represented by the general formula (V) include dimethyl-, diethyl-, dipropyl- and dibutyl esters of phosphonic acid. Specifically, carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethane. Examples include phosphonic acid, carboptoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotooxy-phosphono-phenylacetic acid, carbobutoxy-phosphono-phenylacetic acid, and the like. The phosphorus compound (V) is usually used as a stabilizer and the reaction with the titanium compound proceeds relatively slowly as compared with the phosphorus compound, so that the catalytic activity of the titanium compound has a long duration during the polycondensation reaction, As a result, the amount added to the polyester can be reduced, and even when a large amount of stabilizer is added to the catalyst as in this patent, the polymerization activity of the polyester is hardly impaired. When the titanium compound (I) and the phosphorus compound (V), or the reaction product of the titanium compound (I) and the aromatic polyvalent carboxylic acid compound (II) and the phosphorus compound (V) are reacted, for example, a phosphorus compound ( V) and a solvent are mixed and a part or all of the phosphorus compound is dissolved in the solvent, and the titanium compound (I), or the titanium compound (I) and the aromatic polyvalent carboxylic acid compound (II) are dissolved in the mixed solution. The reaction product is added dropwise, and the reaction system is heated to a temperature of 0 ° C. to 200 ° C. for 10 minutes or longer, preferably 15 to 150 ° C. for 30 to 90 minutes. In this reaction, the reaction pressure is not particularly limited, and may be any of under pressure (0.1 to 0.5 MPa), normal pressure, or reduced pressure (0.001 to 0.1 MPa). Under normal pressure. At this time, the solvent used for the preparation of the phosphorus compound is not particularly limited as long as at least a part of the phosphorus compound (V) can be dissolved. For example, ethanol, ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene And a solvent comprising at least one selected from xylene and the like is preferably used. In particular, it is preferable to use, as a solvent, the same compound as the glycol component constituting the polyester to be finally obtained. In this preparation reaction, the mixing ratio of the titanium compound (I) and the phosphorus compound (V) in the reaction system, or the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) and the phosphorus compound The blending ratio with (V) is such that the molar ratio (mT) of the titanium compound contained in the obtained reaction product and the molar ratio (mPV) of the phosphorus compound in terms of the molar amount of phosphorus (mPV) mT: mPV is 1. : It is preferable to set so that it may become the range of 1-1: 1. A more preferable reaction molar ratio is 1: 1 to 1: 3 of mT: mPV. The reaction product of the titanium compound (I) and the phosphorus compound (V), or the reaction product of the titanium compound (I) and the aromatic polycarboxylic acid compound (II) and the phosphorus compound (V), After the reaction product is separated from the reaction system by means such as centrifugal sedimentation or filtration, it may be used as it is, or the separated reaction product may be used as a recrystallization agent, for example, It may be used after recrystallization and purification with acetone, methyl alcohol and / or water.
Examples of chelating agents for titanium compounds include polyvalent carboxylic acids such as phthalic acid, trimellitic acid, trimesic acid, hemititic acid, pyromellitic acid, and hydroxycarboxylic acids such as lactic acid, malic acid, tartaric acid, and citric acid. As the nitrogen-containing carboxylic acid, ethylenediaminetetraacetic acid, nitrilotripropionic acid, carboxyiminodiacetic acid, carboxymethyliminodipropionic acid, diethylenetriaminopentaacetic acid, triethylenetetraminohexaacetic acid, iminodiacetic acid, iminodipropionic acid Hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, methoxyethyliminodiacetic acid and the like. These titanium compounds may be used alone or in combination.
In the method for producing a polyester of the present invention, it is preferable to add a titanium compound used as a polycondensation catalyst so as to be 0.1 to 50 mass ppm in terms of titanium atom with respect to the obtained polymer. When the content is 0.5 to 20 ppm by mass, the hue and thermal stability of the polymer become better, and more preferably 1 to 15 ppm by mass. Titanium oxide particles added for the purpose of a matting agent are excluded because they do not act as a polycondensation catalyst.
The method for producing the polyester of the present invention includes adding a titanium compound adjusted as an alkylene glycol solution satisfying the formulas (1) and (2) and a hue adjusting agent adjusted as an alkylene glycol solution satisfying the formulas (3) and (4). It is essential to do.
(1) 0.1 ≦ T / W _T ≦ 1.5
(2) 0.01 ≦ W _T ≦ 1.0
(3) 0.01 ≦ C / W _C ≦ 1.0
(4) 0.01 ≦ W _C ≦ 1.0
[T: titanium atom concentration (wt%) in the alkylene glycol preparation solution of titanium compound, W _T : Water content (% by weight) of titanium compound in alkylene glycol preparation solution, C: Hue adjusting agent concentration (% by weight) in alkylene glycol preparation solution of hue adjusting agent, W _C : Water content (weight%) in the alkylene glycol preparation solution of the hue adjusting agent]
By adding the titanium compound as an alkylene glycol solution satisfying the formulas (1) and (2), the catalytic activity is stabilized, so that the polymerization reaction is stabilized. Further, by adding a hue adjusting agent as an alkylene glycol solution satisfying the formulas (3) and (4), it is possible to obtain a polyester in which the generation of foreign matters is suppressed and the hue is improved. The “alkylene glycol solution” in the present invention represents a state in which the titanium compound and the color adjusting agent are partly or wholly dissolved in the alkylene glycol, or are dispersed, suspended, or slurried. When outside the range of the formulas (1) and (2), white foreign matters may be generated in the alkylene glycol solution. Problems such as blockage of the preparation line due to the white foreign matters, deterioration of preparation accuracy, and decrease in polymerization reactivity. May cause. Further, if the formulas (3) and (4) fall outside the range, white foreign matter may be generated in the alkylene glycol solution. Problems such as blockage of the preparation line due to the white foreign matter, deterioration of preparation accuracy, generation of foreign matter, etc. Will be caused. It is more preferable to satisfy the expressions (9) to (12).
(9) 0.2 ≦ T / W _T ≦ 1.0
(10) 0.04 ≦ W _T ≦ 0.9
(11) 0.05 ≦ C / W _C ≦ 0.7
(12) 0.04 ≦ W _C ≦ 0.9
The alkylene glycol used at this time is not particularly limited, but is preferably used from at least one selected from, for example, ethylene glycol, trimethylene glycol, tetramethylene glycol and the like. In particular, it is preferable to use, as a solvent, the same compound as the glycol component constituting the polyester to be finally obtained. Further, the titanium compound and the alkylene glycol solution of the hue adjusting agent may be added separately, or may be added all at once after mixing.
The “hue adjuster” in the present invention represents an organic polyaromatic ring dye or pigment. That is, metal compounds such as cobalt, titanium, chromium, iron, and zinc are not included in the “hue adjuster” in the present invention. Specific examples thereof include a blue color adjusting dye, a purple color adjusting dye, a red color adjusting dye, and an orange color adjusting dye as described later. These may be used alone or in combination of two or more. It is preferable to use a plurality of types in combination in terms of easily satisfying the requirements regarding the visible light absorption spectrum as described later.
In the method for producing the polyester of the present invention, the solution preparation concentration (T) of the alkylene glycol of the titanium compound is preferably 0.01 to 10% by mass. When the solution preparation concentration (T) of the alkylene glycol of the titanium compound is less than the above range, the amount of alkylene glycol added to the polyester is excessively increased, resulting in an increase in cost. When the concentration is higher than the above range, the amount of alkylene glycol is decreased. Therefore, it becomes difficult to adjust the addition amount of the titanium compound. The solution preparation concentration (T) of the alkylene glycol of the titanium compound is preferably in the range of 0.03 to 5% by mass, and more preferably in the range of 0.05 to 1% by mass.
It is preferable that the solution preparation density | concentration (C) of the alkylene glycol of a hue regulator is 0.01-1 mass%. If the solution preparation concentration (C) of the alkylene glycol of the hue adjusting agent is less than the above range, the amount of alkylene glycol added to the polyester is excessively increased, leading to an increase in cost. Therefore, it becomes difficult to adjust the addition amount of the hue adjusting agent. The solution preparation concentration (C) of the alkylene glycol as the hue adjusting agent is preferably in the range of 0.03 to 0.5% by mass, and more preferably in the range of 0.05 to 0.3% by mass.
In the method for producing the polyester of the present invention, it is preferable to add 0.1 to 20 ppm by mass of a hue adjusting agent. When the addition amount of the hue adjusting agent is in the range of 0.1 to 20 ppm by mass, it is preferable because a polyester having a high lightness and a yellowish color can be obtained. More preferably, it is the range of 0.3 mass ppm-10 mass ppm, More preferably, it is the range of 0.5 mass ppm-8 mass ppm.
As a method for producing the polyester of the present invention, a conventionally known polyester production method is used. That is, first, terephthalic acid and ethylene glycol are directly esterified, or a lower alkyl ester of a terephthalic acid component such as dimethyl terephthalate is transesterified with ethylene glycol to produce a dicarboxylic acid glycol ester and / or its low weight. A coalescence is produced. Next, the reaction product is heated under reduced pressure in the presence of a polycondensation catalyst, a phosphorus compound is added until a predetermined degree of polymerization is reached, and then the target polyester is subjected to a polycondensation reaction until the predetermined degree of polymerization is reached. Is manufactured. At the time of the polycondensation reaction, it is preferable that the pressure is finally reduced to a high pressure in order to distill off the generated alkylene glycol component out of the system. Since the polycondensation reaction of polyester is an equilibrium reaction, it is important to distill off alkylene glycol out of the system in order to efficiently obtain high molecular weight polyester. The pressure finally reached is preferably 1 to 100 Pa, and more preferably 1 to 50 Pa. However, the hue adjusting agent added in the present invention may be distilled out of the reaction system together with the generated alkylene glycol when the reaction system is highly decompressed. If the hue modifier is distilled out of the reaction system together with the alkylene glycol, the hue modifier will not be contained in the desired amount of polyester, and the resulting hue of the polyester will change. It is not preferable. In addition, the alkylene glycol distilled off from the reaction system may be purified after being concentrated in a condenser and used again in the production of polyester. However, if a large amount of a hue adjusting agent is contained at that time, the hue will be greatly changed. In some cases, the quality of the polyester may be greatly impaired by becoming a foreign material. It is described above that the remaining ratio of the hue adjusting agent (the remaining ratio of the hue adjusting agent = the content of the hue adjusting agent in the polymer / the added amount of the hue adjusting agent × 100 (%)) is in the range of 50% to 100%. This is preferable because the above problem can be avoided. More preferably, it is in the range of 60% to 100%, and particularly preferably in the range of 70% to 100%. By adjusting the alkylene glycol solution of the hue adjusting agent at the above-described adjusting concentration, and maintaining the temperature within the range of 100 ° C. to 180 ° C. before being introduced into the polyester production process, the hue adjusting agent is released to the outside of the system. Distillation can be extremely suppressed. Although this effect is not known in detail, it is presumed that this effect is caused to improve the compatibility of the hue modifier and the alkylene glycol solution by adjusting the hue modifier at the above-mentioned concentration and temperature. . The temperature maintained until it is introduced into the polyester production process of the alkylene glycol solution of the hue adjusting agent is preferably in the range of 110 to 170 ° C, more preferably in the range of 120 to 160 ° C.
In the present invention, “by the time it is added to the polyester production process” means that the hue adjusting agent is adjusted to an alkylene glycol solution, stored in an alkylene glycol solution, and put into the polyester production process. When divided, it indicates that the temperature is maintained at least at the storage stage and at the stage of the polyester production process. The holding time is preferably at least 5 minutes, more preferably 15 minutes or more, and most preferably 20 minutes or more. More preferably, it is maintained at a temperature of 100 to 180 ° C. in all stages of adjusting the hue adjusting agent to the alkylene glycol solution, storing in the alkylene glycol solution, and charging to the polyester production process. . In the stage of storing the hue adjusting agent in an alkylene glycol solution, it is preferable to circulate or stir at a flow rate of 10 m / min or more. When the flow rate is less than 10 m / min, an undissolved hue adjusting agent may be precipitated, which is not preferable. The holding of the hue adjusting agent solution or dispersion is more preferably in the range of a flow rate of 15 to 100 m / min. The flow rate can be calculated and controlled as follows, for example. If the hue modifier solution or dispersion is circulating, install a current meter in the middle of the circulating pipe, and if the hue modifier solution or dispersion is being stirred, When a circular stirring tank is used, it can be appropriately calculated from the rotation speed of the stirring blade, the diameter of the stirring tank, and the like.
It is essential that the titanium compound be added at any stage until the polycondensation reaction step in the polyester production process is completed. A method of adding a catalyst immediately after the addition of a raw material such as a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof as an esterification reaction catalyst or a transesterification reaction catalyst, or a method of adding a catalyst accompanied with the raw material However, when it is added as a polycondensation reaction catalyst, it may be substantially before the start of the polycondensation reaction, and the polycondensation reaction catalyst is started before or after the esterification reaction or transesterification reaction. It may be added before.
It is essential that the hue adjusting agent be added at any stage until the polycondensation reaction step in the polyester production process is completed. A method of adding a color adjusting agent to the polyester by melt kneading after preparing the polyester to a desired degree of polymerization leads to an increase in cost, and is not included in the present application. It is particularly preferable to add the hue adjusting agent after the esterification reaction or transesterification reaction is completed.
Furthermore, the hue adjusting agent has a maximum absorption wavelength in the range of 540 to 650 nm when the visible light absorption spectrum in the wavelength range of 380 to 780 nm is measured for a chloroform solution having a concentration of 20 mg / L at an optical path length of 1 cm, and the maximum absorption is obtained. When the ratio of the absorbance at each wavelength to the absorbance at the wavelength satisfies all of the formulas (5) to (8), the lightness of the hue of the resulting polyester is high and the yellowness is suppressed, which is preferable.
0.00 ≦ A400 / Amax ≦ 0.20 (5)
0.10 ≦ A500 / Amax ≦ 0.70 (6)
0.55 ≦ A600 / Amax ≦ 1.00 (7)
0.00 ≦ A700 / Amax ≦ 0.05 (8)
[In the formulas (5) to (8), A400, A500, A600 and A700 represent the absorbance in the visible light absorption spectrum at wavelengths of 400 nm, 500 nm, 600 nm and 700 nm, respectively, and Amax represents the absorbance in the visible light absorption spectrum at the maximum absorption wavelength. Represents absorbance. ]
Here, the visible light absorption spectrum is a spectrum usually measured by a spectrophotometer, but the maximum absorption wavelength of the visible light absorption spectrum of the hue adjusting agent solution contained in the polyester obtained by the production method of the present invention is 540 nm. If it is less than 650 nm, the redness of the resulting polyester will be strong, and if it exceeds 650 nm, the blueness of the resulting polyester will be strong. The range of the maximum absorption wavelength is preferably 545 to 595 nm, and more preferably 550 to 590 nm.
Preferably, all of the formulas (5) to (8) are satisfied, and any one or more of the formulas (13) to (16) is satisfied. More preferably, the formulas (5) to (8) and the formula (13) are satisfied. (16) It is to satisfy all.
0.00 ≦ A400 / Amax ≦ 0.15 (13)
0.30 ≦ A500 / Amax ≦ 0.60 (14)
0.60 ≦ A600 / Amax ≦ 0.95 (15)
0.00 ≦ A700 / Amax ≦ 0.03 (16)
[In the formulas (13) to (16), A400, A500, A600 and A700 represent the absorbance in the visible light absorption spectrum at wavelengths of 400 nm, 500 nm, 600 nm and 700 nm, respectively, and Amax represents the absorbance in the visible light absorption spectrum at the maximum absorption wavelength. Represents absorbance. ]
The hue adjusting agent used in the present invention is selected from color adjusting dyes having a mass decrease starting temperature of 250 ° C. or higher when measured with a thermobalance in a nitrogen atmosphere at a temperature rising rate of 10 ° C./min. It is preferable. Here, the mass decrease start temperature when measured with a thermobalance is the mass decrease start temperature (T1) described in JISK-7120, and is an index of the thermal stability of the hue adjusting agent. . When the mass decrease starting temperature is less than 250 ° C., the thermal stability of the hue adjusting agent is insufficient, which is not preferable because it causes coloring of the finally obtained polyester. The mass decrease starting temperature is more preferably 300 ° C. or higher. More preferably, the polyester does not decompose at a temperature at which it is in a molten state.
In the method for producing the polyester of the present invention, a blue hue adjusting dye and a purple hue adjusting dye are used in combination in a mass ratio of 90:10 to 40:60 as a hue adjusting agent, or for blue hue adjustment. It is preferable to use the dye and the red or orange hue adjusting dye in a mass ratio of 98: 2 to 80:20. Here, the blue-based hue adjusting dye is generally described as “Blue” among commercially available hue adjusting dyes, and specifically, the maximum absorption in a visible light absorption spectrum in a solution. The wavelength is about 580 to 650 nm. Similarly, a purple hue adjusting dye is a "Violet" among commercially available hue adjusting dyes. Specifically, the maximum absorption wavelength in a visible light absorption spectrum in a solution is The thing in about 560-580 nm is shown. The red-based hue adjusting dye is represented by “Red” among commercially available hue adjusting dyes, and specifically has a maximum absorption wavelength of 480 to 480 in a visible light absorption spectrum in a solution. It is about 520 nm. The orange-based hue adjusting dye is the one described as “Orange” among commercially available hue adjusting dyes.
As these hue adjusting dyes, oil-soluble dyes are particularly preferable. As specific examples of blue hue adjusting dyes, C.I. I. SolventBlue 11, C.I. I. SolventBlue 25, C.I. I. SolventBlue 34, C.I. I. SolventBlue 35, C.I. I. SolventBlue 36, C.I. I. Solvent Blue 45 (Telasol Blue RLS), C.I. I. SolventBlue 55, C.I. I. SolventBlue 63, C.I. I. SolventBlue 70, C.I. I. SolventBlue 78, C.I. I. SolventBlue 83, C.I. I. Solvent Blue 87, C.I. I. SolventBlue 94, C.I. I. SolventBlue 104, C.I. I. SolventBlue 117, C.I. I. SolventBlue122 etc. are mentioned. Examples of the purple hue adjusting dye include C.I. I. SolventViolet 8, C.I. I. SolventViolet 13, C.I. I. SolventViolet 14, C.I. I. SolventViolet 21, C.I. I. SolventViolet 27, C.I. I. SolventViolet 28, C.I. I. SolventViolet 36, C.I. I. SolventViolet 37, C.I. I. SolventViolet 49 etc. are mentioned. Examples of red hue adjusting dyes include C.I. I. SolventRed24, C.I. I. SolventRed 25, C.I. I. SolventRed27, C.I. I. SolventRed30, C.I. I. SolventRed49, C.I. I. SolventRed52, C.I. I. SolventRed100, C.I. I. SolventRed109, C.I. I. SolventRed111, C.I. I. SolventRed121, C.I. I. SolventRed135, C.I. I. SolventRed168, C.I. I. SolventRed179, C.I. I. SolventRed195 etc. are illustrated. Examples of the orange hue adjusting dye include C.I. I. Solvent Orange 60 etc. are mentioned.
Here, when a blue hue adjusting dye and a purple hue adjusting dye are used in combination, if the mass ratio of the blue hue adjusting dye is larger than 90:10, the color a value of the obtained polyester becomes small. If the mass ratio of the dye for adjusting the blue hue is smaller than 40:60, the color a value increases and a red color is exhibited, which is not preferable. Similarly, when a blue hue adjusting dye and a red or orange hue adjusting dye are used in combination, if the mass ratio of the blue hue adjusting dye is larger than 98: 2, the color a value of the obtained polyester Is small and exhibits a green color, and when the mass ratio of the blue hue adjusting dye is smaller than 80:20, the color a value increases and a red color is exhibited. The hue adjusting dye is a combination of a blue hue adjusting dye and a purple hue adjusting dye in a mass ratio of 80:20 to 50:50, or a blue hue adjusting dye and a red or orange dye. It is more preferable to use the hue adjusting dye in a mass ratio of 95: 5 to 90:10.
In the method for producing the polyester of the present invention, it is essential to add a phosphorus compound between the time when the pressure reduction in the polymerization reactor is started and the polycondensation reaction is started until the polyester reaches the target degree of polymerization. is there. By adding the phosphorus compound under the above conditions, it is possible to obtain a polyester in which the polymerization reaction is stable, the generation of foreign matters is suppressed, and the hue is improved. Polyester is usually produced by adding a polycondensation catalyst to dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative, and then proceeding the polycondensation reaction by reducing the pressure in the reactor. . Polyesters are required to have various degrees of polymerization depending on the application and purpose. Therefore, when the desired degree of polymerization is reached, the polycondensation reaction is stopped by setting the inside of the reactor to normal pressure or pressure, and the polyester is discharged outside the reactor. In the present invention, the phosphorus compound is added after the inside of the polymerization reactor is decompressed to start the polycondensation reaction until the polyester reaches the target degree of polymerization.
The phosphorus compound of the present invention may be added at any time during the period from the start of the polycondensation reaction by reducing the pressure in the reactor until the polymerization is substantially completed. When the viscosity is added at a time of 40 to 99% of the intended intrinsic viscosity, it is preferable because side reactions can be suppressed with very little deactivation of the polycondensation catalyst. Preferably it is between 50 and 98%, particularly preferably between 75 and 98%. The intrinsic viscosity of the polyester at the time when the phosphorus compound is added may be calculated by directly sampling and measuring the viscosity by the method described later, or may be calculated from the torque load applied to the stirring blade of the reactor.
In the case of adding a phosphorus compound under the above conditions, if a large amount of a diol component such as ethylene glycol is brought in and added, the depolymerization of the polyester (polyester main chain cleavage reaction) proceeds. A method of adding alone or adding a master pellet containing a phosphorus compound at a high concentration, and a method of adding a diol component such as ethylene glycol containing a phosphorus compound at a high concentration as a solvent are preferred. At this time, the phosphorus compound may be added in several portions, or may be continuously added with a feeder or the like. In addition, the above-described method for adding a phosphorus compound is preferably added in a container that can be dissolved or melted in a polymerization system and is made of a polymer having substantially the same component as the polymer obtained in the present invention. . When the phosphorus compound is added to the container as described above and added, the addition of the polymerization reactor under the reduced pressure condition may cause the phosphorus compound to scatter and prevent the phosphorus compound from flowing out to the reduced pressure line. In addition, a desired amount of the phosphorus compound can be stably added to the polymer. The “container” in the present invention is not limited as long as it contains phosphorus compounds, and includes, for example, an injection-molded container having a lid or a stopper, or a sheet or film formed into a bag shape by sealing or sewing. . More preferably, the container described above creates an air vent. When a phosphorus compound is added to a container that has been vented, even if it is added to the polymerization reactor under vacuum conditions, the container bursts due to air expansion and the phosphorus compound flows out to the decompression line, or the upper part of the polymerization reactor. The phosphorus compound can be added to the polymer in a desired amount without adhering to the wall surface. If the container is too thick, it takes longer to dissolve and melt, so it is better to make the container thinner. However, the container should be thick enough not to rupture when the phosphorus compound is sealed or added. For this purpose, a material having a thickness of 10 to 500 μm and uniform thickness is preferable.
The phosphorus compound is not particularly limited between the start of the pressure reduction in the polymerization reactor and the start of the polycondensation reaction until the polyester reaches the target degree of polymerization, but the phosphite compound, phosphate compound, phosphonite compound, It is preferably selected from one or more compounds selected from phosphonate compounds, phosphinite compounds, and phosphinate compounds. Examples of the phosphite compound include phosphorous acid, phosphorous acid monoalkyl ester, phosphorous acid dialkyl ester, phosphorous acid trialkyl ester, and alkali metal salts thereof. Specific examples include phosphorous acid, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, and sodium phosphite. Examples of the phosphate compound include phosphoric acid, phosphoric acid monoalkyl ester, phosphoric acid dialkyl ester, phosphoric acid trialkyl ester, and alkali metal salts thereof. Specific examples include phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, and sodium phosphate. Examples of the phosphonite compound include phosphonous acid, phosphonous acid monoalkyl ester, phosphonous acid dialkyl ester, phosphonous acid trialkyl ester, and alkali metal salts thereof. Specific examples include methylphosphonous acid, ethylphosphonous acid, propylphosphonous acid, isopropylphosphonous acid, butylphosphonous acid, and phenylphosphonous acid. Examples of the phosphonate compound include phosphonic acid, phosphonic acid monoalkyl ester, phosphonic acid dialkyl ester, phosphonic acid trialkyl ester, and alkali metal salts thereof. Specifically, sodium phosphonate, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthyl Phosphonic acid, anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic acid, 2,4-dicarboxyphenylphosphonic acid, 2 , 5-dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,3,4-tricarboxyphenylphosphonic acid , 2, , 5-tricarboxyphenylphosphonic acid, 2,3,6-tricarboxyphenylphosphonic acid, 2,4,5-tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, methylphosphonic acid dimethyl ester, Methylphosphonic acid diethyl ester, ethylphosphonic acid dimethyl ester, ethylphosphonic acid diethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, benzylphosphonic acid dimethyl ester, benzylphosphonic acid diethyl ester, benzylphosphonic acid Diphenyl ester, lithium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), sodium (3,5-di-tert-butyl-4-hydroxy) Loxybenzylphosphonate ethyl), magnesium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate), calcium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate) Diethylphosphonoacetic acid, methyl diethylphosphonoacetate, ethyl diethylphosphonoacetate and the like. Examples of the phosphinite compound include phosphinic acid, phosphinic acid monoalkyl ester, phosphinic acid dialkyl ester, phosphinic acid trialkyl ester, and alkali metal salts thereof. Specifically, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, Examples include diisopropylphosphinic acid, dibutylphosphinic acid, diphenylphosphinic acid, and the like. Examples of the phosphinate compound include hypophosphorous acid, hypophosphorous acid monoalkyl ester, hypophosphorous acid dialkyl ester, hypophosphorous acid trialkyl ester, and alkali metal salts thereof. Specifically, sodium hypophosphite, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, tolylphosphinic acid, xylylphosphinic acid, biphenylylphosphinic acid, diphenyl Phosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, ditolylphosphinic acid, dixylphosphinic acid, dibiphenylylphosphinic acid, naphthylphosphinic acid, anthrylphosphinic acid, 2 -Carboxyphenylphosphinic acid, 3-carboxyphenylphosphinic acid, 4-carboxyphenylphosphinic acid, 2,3-dicarboxyphenylphosphinic acid, 2,4-dicarboxyph Nylphosphinic acid, 2,5-dicarboxyphenylphosphinic acid, 2,6-dicarboxyphenylphosphinic acid, 3,4-dicarboxyphenylphosphinic acid, 3,5-dicarboxyphenylphosphinic acid, 2,3,4- Tricarboxyphenylphosphinic acid, 2,3,5-tricarboxyphenylphosphinic acid, 2,3,6-tricarboxyphenylphosphinic acid, 2,4,5-tricarboxyphenylphosphinic acid, 2,4,6-tricarboxy Phenylphosphinic acid, bis (2-carboxyphenyl) phosphinic acid, bis (3-carboxyphenyl) phosphinic acid, bis (4-carboxyphenyl) phosphinic acid, bis (2,3-dicarboxylphenyl) phosphinic acid, bis ( 2,4-dicarboxyphenyl) phosphinic acid, bis ( , 5-Dicarboxyphenyl) phosphinic acid, bis (2,6-dicarboxyphenyl) phosphinic acid, bis (3,4-dicarboxyphenyl) phosphinic acid, bis (3,5-dicarboxyphenyl) phosphinic acid, bis (2,3,4-tricarboxyphenyl) phosphinic acid, bis (2,3,5-tricarboxyphenyl) phosphinic acid, bis (2,3,6-tricarboxyphenyl) phosphinic acid, bis (2,4,4) 5-tricarboxyphenyl) phosphinic acid and bis (2,4,6-tricarboxyphenyl) phosphinic acid, methylphosphinic acid methyl ester, dimethylphosphinic acid methyl ester, methylphosphinic acid ethyl ester, dimethylphosphinic acid ethyl ester, ethyl Phosphinic acid methyl ester, diethylphosphite Acid methyl ester, ethylphosphinic acid ethyl ester, diethylphosphinic acid ethyl ester, phenylphosphinic acid methyl ester, phenylphosphinic acid ethyl ester, phenylphosphinic acid phenyl ester, diphenylphosphinic acid methyl ester, diphenylphosphinic acid ethyl ester, diphenylphosphinic acid Examples include phenyl ester, benzylphosphinic acid methyl ester, benzylphosphinic acid ethyl ester, benzylphosphinic acid phenyl ester, bisbenzylphosphinic acid methyl ester, bisbenzylphosphinic acid ethyl ester, and bisbenzylphosphinic acid phenyl ester. Among these, phosphorus compounds represented by general formulas (III), (IV), (V), (VI), (VII), (VIII), and (IX) are preferable.

[In the formula (VI), R ⁹ , R ¹⁰ and R ¹¹ each independently represent hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxy group containing 1 to 50 carbon atoms, The hydrogen group may contain an alicyclic structure such as cyclohexyl, an aliphatic branched structure, and an aromatic ring structure such as phenyl or naphthyl. a, b, c and a + b + c are integers of 0 to 5, and d is 0 or 1. ]

[In Formula (VII), R ^{12 to} R ¹⁴ each independently represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxy group, and a hydrocarbon group having 1 to 50 carbon atoms. May contain an alicyclic structure such as cyclohexyl, an aliphatic branched structure, and an aromatic ring structure such as phenyl or naphthyl. e represents an integer of 0 to 5, and f represents 0 or 1. ]

[In the formula (VIII), R ^{15 to} R ¹⁷ each represent an independent hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms including a hydroxyl group or an alkoxy group, It may contain an alicyclic structure such as cyclohexyl, an aliphatic branched structure, or an aromatic ring structure such as phenyl or naphthyl. g represents an integer of 0 to 5, and h represents 0 or 1. ]

[In the formula (IX), R ^{18 to} R ¹⁹ each independently represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxy group, and a hydrocarbon group having 1 to 50 carbon atoms. May contain an alicyclic structure such as cyclohexyl, an aliphatic branched structure, and an aromatic ring structure such as phenyl or naphthyl. i represents 0 or 1; ]
As the phosphorus compound represented by (VI), bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-tert-butylphenyl) Pentaerythritol di-phosphite. Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite is available from Asahi Denka Co., Ltd. as ADK STAB PEP-36. Bis (2,4-di-tert-butylphenyl) pentaerythritol di-phosphite is available from Asahi Denka Co., Ltd. as ADK STAB PEP-24G, or from Ciba Specialty Chemicals Co., Ltd. as IRGAFOS126. Examples of the phosphorus compound represented by (VII) include phenylphosphonite, 2-carboxyphenylphosphonite, 3-carboxyphenylphosphonite, 4-carboxyphenylphosphonite, 2,3-dicarboxyphenylphosphonite, 2,4 -Dicarboxyphenylphosphonite, 2,5-dicarboxyphenylphosphonite, 2,6-dicarboxyphenylphosphonite, 3,4-dicarboxyphenylphosphonite, 3,5-dicarboxyphenylphosphonite, 2,3 , 4-Tricarboxyphenylphosphonite, 2,3,5-tricarboxyphenylphosphonite, 2,3,6-tricarboxyphenylphosphonite, 2,4,5-tricarboxyphenylphosphonite, 2,4,6 -Tricarboxyphenylphosphonite, Fe Ruphosphonite dimethyl, phenylphosphonite diethyl, phenylphosphonite diphenyl, phenylphosphonite dibenzyl, 2,4-di-t-butylphenylphosphonite diethyl, 2,4-di-t-butyl-5-methylphenylphospho F = 0 phosphonous acid compounds such as nitrite diethyl, phenylphosphonate, 2-carboxyphenylphosphonate, 3-carboxyphenylphosphonate, 4-carboxyphenylphosphonate, 2,3-dicarboxyphenylphosphonate, 2,4-dicarboxy Phenylphosphonate, 2,5-dicarboxyphenylphosphonate, 2,6-dicarboxyphenylphosphonate, 3,4-dicarboxyphenylphosphonate, 3,5-dicarboxyphenylphosphonate, 2,3,4-tri Ruboxyphenyl phosphonate, 2,3,5-tricarboxyphenyl phosphonate, 2,3,6-tricarboxyphenyl phosphonate, 2,4,5-tricarboxyphenyl phosphonate, 2,4,6-tricarboxyphenyl phosphonate, phenyl F = 1 such as phosphonate dimethyl, phenylphosphonate diethyl, phenylphosphonate diphenyl, phenylphosphonate dibenzyl, 2,4-di-t-butylphenylphosphonate diethyl, 2,4-di-t-butyl-5-methylphenylphosphonate diethyl And phosphonic acid compounds. Examples of the phosphorus compound represented by (VIII) include dimethyl [1,1-biphenyl] -4-ylphosphonite, diethyl [1,1-biphenyl] -4-ylphosphonite, dibutyl [1,1-biphenyl]. -4-ylphosphonite, dihexyl [1,1-biphenyl] -4-ylphosphonite, dioctyl [1,1-biphenyl] -4-ylphosphonite, dibenzyl [1,1-biphenyl] -4-ylphospho Knight, di-t-butyl [1,1-biphenyl] -4-ylphosphonite, diphenyl [1,1-biphenyl] -4-ylphosphonite, bis (2,4-di-t-butylphenyl) [ 1, 0-substituent such as 1,1-biphenyl] -4-ylphosphonite, bis (2,4-di-t-butyl-5-methylphenyl) [1,1-biphenyl] -4-ylphosphonite Phosphonic acid Compounds, dimethyl [1,1-biphenyl] -4-ylphosphonate, diethyl [1,1-biphenyl] -4-ylphosphonate, dibutyl [1,1-biphenyl] -4-ylphosphonate, dihexyl [1,1- Biphenyl] -4-ylphosphonate, dioctyl [1,1-biphenyl] -4-ylphosphonate, dibenzyl [1,1-biphenyl] -4-ylphosphonate, di-t-butyl [1,1-biphenyl] -4 -Ylphosphonate, diphenyl [1,1-biphenyl] -4-ylphosphonate, bis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4-ylphosphonate, bis (2,4- And h = 1 phosphonic acid compounds such as di-t-butyl-5-methylphenyl) [1,1-biphenyl] -4-ylphosphonate. Examples of the phosphorus compound represented by (IX) include tetramethyl [1,1-biphenyl] -4,4′-diylbisphosphonite, tetraethyl [1,1-biphenyl] -4,4′-diylbisphosphonite. , Tetrabutyl [1,1-biphenyl] -4,4′-diylbisphosphonite, tetrahexyl [1,1-biphenyl] -4,4′-diylbisphosphonite, tetraoctyl [1,1-biphenyl] − 4,4'-diylbisphosphonite, tetrabenzyl [1,1-biphenyl] -4,4'-diylbisphosphonite, tetra-t-butyl [1,1-biphenyl] -4,4'-diylbisphosphonite Phosphonites of i = 0 such as knight, tetraphenyl [1,1-biphenyl] -4,4′-diylbisphosphonite, tetramethyl [1,1-biphenyl] -4,4′-diylbis Sulfonate, tetraethyl [1,1-biphenyl] -4,4′-diylbisphosphonate, tetrabutyl [1,1-biphenyl] -4,4′-diylbisphosphonate, tetrahexyl [1,1-biphenyl] -4,4 ′ -Diylbisphosphonate, tetraoctyl [1,1-biphenyl] -4,4'-diylbisphosphonate, tetradodecyl [1,1-biphenyl] -4,4'-diylbisphosphonate, tetrabenzyl [1,1-biphenyl]- I = 1 such as 4,4′-diylbisphosphonate, tetra-t-butyl [1,1-biphenyl] -4,4′-diylbisphosphonate, tetraphenyl [1,1-biphenyl] -4,4′-diylbisphosphonate And phosphonic acid compounds. Among them, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, tetrakis (2,4-di-t-butyl-5-methylphenyl) [ 1,1-biphenyl] -4,4′-diylbisphosphonite, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonate, tetrakis (2, 4-di-t-butylphenyl-5-methyl) [1,1-biphenyl] -4,4′-diylbisphosphonate is preferably used. Tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite is available from Ciba Specialty Chemicals as IRGAFOSP-EPQ or Clariant as SandostabP-EPQ.・ Available from Japan. Tetrakis (2,4-di-t-butyl-5-methylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite is available from Osaki Kogyo as GSY-P101. Tetraethyl [1,1-biphenyl] -4,4′-diylbisphosphonate, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonate It is available from the corporation. These phosphorus compounds may be used alone or in combination of two or more.
The amount of phosphorus compound added between the start of the pressure reduction in the polymerization reactor and the start of the polycondensation reaction until the polyester reaches the target degree of polymerization is not particularly limited. The total amount is preferably in the range of 1 to 10,000 ppm by mass in terms of phosphorus atoms. When the addition amount is within the above range, a polyester having a good hue and excellent thermal stability can be obtained. More preferably, it is the range of 1-1000 mass ppm, Most preferably, it is the range of 10-500 mass ppm.
In the method for producing the polyester of the present invention, it is of course possible to add a phosphorus compound before starting the pressure reduction in the polymerization reactor. However, if the phosphorus compound is added before the pressure reduction in the polymerization reactor is started, depending on the amount of the phosphorus compound added, the activity of the titanium compound that is a polycondensation catalyst is suppressed by the phosphorus compound in the polymerization reaction system. When the amount of the phosphorus compound added is large, the polymerization reaction time may be delayed. Therefore, it is preferable that the addition amount of the phosphorus compound added before starting the pressure reduction in the polymerization reactor is 1000 mass ppm or less in total in terms of phosphorus atoms with respect to the obtained polyester. Although it does not specifically limit as a phosphorus compound used at this time, The phosphorus compound represented by general formula (III), (IV), (V), (VI), (VII), (VIII), (IX) is preferable.
The polyester obtained by the present invention preferably has a content of a metal element having a true specific gravity of 5.0 or more of 0 to 10 ppm by mass. In the present invention, “true specific gravity” refers to specific gravity that does not include voids, and “specific gravity” refers to the ratio of the mass of a substance in the same volume to a standard substance (water at 4 ° C.). The “metal element having a true specific gravity of 5.0 or more” is derived from a metal compound usually contained in a catalyst, a metal-based hue adjusting agent, a matting agent, or the like contained in a polyester. Specific examples of the metal having a true specific gravity of 5.0 or more include antimony, germanium, manganese, cobalt, tin, zinc, lead, cadmium, and the like. It is contained in polyester as an agent. Other examples include iron, nickel, niobium, molybdenum, tantalum, and tungsten. On the other hand, titanium, calcium, potassium, aluminum, magnesium, sodium, lithium, and the like do not correspond to metals having a true specific gravity of 5.0 or more. The characteristics and properties vary depending on the type of metal contained. For example, when the content of antimony metal is more than 10 ppm by mass, it becomes a foreign substance during melt spinning or film formation and adheres to the periphery of the die or die. This will adversely affect the continuous formability of the period. In the case of germanium metal, since it is expensive per se, the price of the resulting polyester is undesirably increased as the content increases. In addition, in the case of metals such as lead and cadmium, since the metal element itself is toxic, it is not preferable to contain a large amount in the polyester. The content of the metal element having a true specific gravity of 5.0 or more is preferably 0 to 7 mass ppm or less, and particularly preferably 0 to 5 mass ppm or less.
In the method for producing the polyester of the present invention, a phenolic antioxidant may be added. The phenolic antioxidant is a radical chain reaction inhibitor having a phenol structure, specifically 2,6-t-butyl-p-cresol, butylhydroxyanisole, 2,6-t-butyl- 4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis {1,1-dimethyl-2- {β- (3- t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,8,10-tetraoxaspiro {5,5} undecane, 1,1,3-tris 2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, Tetrakis- {methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate} methane, bis {3,3'-bis- (4'-hydroxy-3'-t- Butylphenyl) butyric acid} glycol ester, tocopherol, pentaerythritol-tetrakis [3,5-di-t-butyl-4-hydroxyphenyl) propionate. These phenolic antioxidants may be used alone or in combination. The addition amount is not particularly limited, but is usually in the range of 1 to 10% by weight, preferably 100 to 1% by weight, based on the polymer obtained as the weight of the compound to be added.
In the method for producing the polyester of the present invention, a sulfur-based antioxidant may be added. A sulfur-based antioxidant is a sulfur-based antioxidant that reduces peroxides in a form that does not generate radicals, and is oxidized by itself, specifically, dilauryl 3,3′-thiodipropionate. , Dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate and the like, and these sulfur-based antioxidants may be used alone or in combination. The addition amount is not particularly limited, but is usually in the range of 1 to 10% by weight, preferably 100 to 1% by weight, based on the polymer obtained as the weight of the compound to be added.
The polyester obtained by the production method of the present invention preferably has an intrinsic viscosity of 0.3 to 1.0 dlg ⁻¹ when measured by a measurement method described later. More preferably from 0.4~0.8dlg ^-1, particularly preferably from 0.5~0.75dlg ^-1.
In the polyester obtained by the production method of the present invention, the hue in the chip shape is a hunter value, the L value is 60 to 95, the a value is -6 to 2, and the b value is in the range of -3 to 7, It is preferable from the viewpoint of the hue of a molded product such as a fiber or a film. More preferably, the L value ranges from 70 to 90, the a value ranges from -5 to 1, and the b value ranges from -2 to 5.
The polyester obtained by the production method of the present invention was dried under reduced pressure at 150 ° C. for 12 hours and then changed in hue b value after being melted at 290 ° C. for 60 minutes in a nitrogen atmosphere, and the Δb value 290 was −5 to 5 A range is preferable. The smaller this value, the less the decomposition and coloring due to thermal deterioration, and the better the thermal stability. If this value exceeds 5, the polymer will be discolored during spinning or molding, which will have a significant effect on quality. Preferably it is 4 or less, particularly preferably 3 or less.
The polyester obtained by the production method of the present invention is useful as a fiber by forming into a filament shape by, for example, melt extrusion molding or the like and then stretching or spinning. The production method for producing this polyester fiber is not particularly limited, and a conventionally known melt spinning method is used. For example, it is preferable to produce the dried polyester by melt spinning at a temperature in the range of 270 ° C. to 300 ° C., and the spinning speed of the melt spinning is preferably 400 to 5000 m / min. When the spinning speed is in this range, the strength of the obtained fiber is sufficient, and the winding can be stably performed. Further, the shape of the die used at the time of spinning is not particularly limited, and any of circular, irregular, solid and hollow can be adopted. Further, the drawn yarn can be obtained by drawing the undrawn polyester fiber once or by continuously drawing it without winding. As a form of the fiber, it can be used as a core-sheath type composite fiber, a core-sheath type composite hollow fiber, a sea-island type composite fiber, etc., and can be used as a constituent component at an arbitrary ratio.

Hereinafter, the present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples. In addition, the physical-property value in an Example was measured by the method described below.
(1) Intrinsic viscosity of polymer IV
A diluted solution in which orthochlorophenol was dissolved as a solvent at 100 ° C. for 60 minutes was measured at 25 ° C. using an Ubbelohde viscometer.
(2) Polymer Diethylene Glycol (DEG) Content Using monoethanolamine as a solvent, a 1,6-hexanediol / methanol mixed solution was added, cooled, neutralized, centrifuged, and the supernatant was subjected to gas chromatography (Shimadzu). It was measured by Seisakusho Co., Ltd., GC-14A).
(3) Using a polymer hue color difference meter (SM color computer model SM-T45, manufactured by Suga Test Instruments Co., Ltd.), it was measured as a Hunter value (L, a, b value).
(4) Δb value 290
After the polyester was dried under reduced pressure at 150 ° C. for 12 hours and then heated and melted at 290 ° C. for 60 minutes in a nitrogen atmosphere, the hue was measured by the method of (3). It was measured.
(5) In the measurement of titanium in the polycondensation catalyst, titanium of the phosphorus atom concentration prepared catalyst, phosphorus atom concentration, the dried catalyst sample was set in a scanning electron microscope (S570 model manufactured by Hitachi Instrument Service Co., Ltd.) Using an energy dispersive X-ray microanalyzer (XMA, EMAX-7000 manufactured by Horiba, Ltd.) connected thereto, the titanium and phosphorus atom concentrations in the polycondensation catalyst were determined.
(6) Titanium, phosphorus, antimony, and cobalt element content in polymer After a chip-like sample is heated and melted on an aluminum plate, a compact having a flat surface is produced by a compression press machine, and an X-ray fluorescence elemental analyzer ( Rigaku Denki Kogyo Co., Ltd., System 3270). That is, polyester is dissolved in orthochlorophenol, the viscosity of the polymer solution is adjusted with chloroform as necessary, and then the particles are precipitated with a centrifuge. Thereafter, only the supernatant liquid is collected by a gradient method, and the polymer is reprecipitated by adding acetone, filtered and washed to obtain a polymer from which particles are removed.
(7) Metal component qualitative analysis polyester having a true specific gravity of 5.0 or more is mixed with ammonium sulfate, sulfuric acid, nitric acid and perchloric acid, wet-decomposed at about 300 ° C. for 9 hours, diluted with distilled water, and Rigaku Denki Kogyo Co., Ltd. Qualitative analysis was performed using an ICP emission analyzer (JY170ULTRACE) manufactured, and the presence or absence of a metal element having a true specific gravity of 5.0 or more was confirmed. About the metal element by which presence of 1 mass ppm or more was confirmed, the element content was shown.
(8) Residual rate of hue adjusting agent in polymer Except for the presence or absence of the addition of a hue adjusting agent, a polycondensation reaction was carried out under the same conditions to prepare two types of polymers, one with and without adding a hue adjusting agent. The two types of polymers were dissolved in orthochlorophenol at 150 ° C., and the absorbance difference was measured using a spectrophotometer (U-3000, manufactured by HITACHI). The content of the hue adjusting agent was calculated from the difference in absorbance, and the residual ratio of the hue adjusting agent was calculated as the content of the hue adjusting agent in the polymer / the added amount of the hue adjusting agent × 100 (%).
(9) Mass reduction start temperature of hue adjusting agent The temperature was measured in a nitrogen atmosphere at a heating rate of 10 ° C./min according to JISK7120 using a TAS-200 thermobalance manufactured by Rigaku Denki Kogyo Co., Ltd.
(10) Water content in alkylene glycol KF moisture content meter (manufactured by Kyoto Denshi Kogyo Co., Ltd., MKC-210) was used to measure the amount of water, which was calculated as mass% based on alkylene glycol.
(11) Observation of the deposit in the die After the polyester was chipped, it was vacuum dried at 150 ° C. for 15 hours to bring the moisture content into the range of 10 to 50 mass ppm, and then the spinning temperature was 285 ° C., the pore diameter was 0.18 mmφ, and the number of holes was 16. The amount of deposits around the nozzle hole after discharging from each spinneret and spinning at 1000 m / min for 72 hours was observed using a long focus microscope. The state in which deposits were hardly recognized was judged as ◯, the state in which deposits were recognized but operable was judged as Δ, and the state in which deposits were found and yarn breakage frequently occurred was judged as ×.
Reference Example 1 (Synthesis of polycondensation catalyst A)
Titanium tetrabutoxide was added to an ethylene glycol solution (0.2% by mass) of trimellitic anhydride with respect to trimellitic anhydride in an amount of 1/2 mol, and the reaction was carried out for 60 minutes while maintaining at 80 ° C. under atmospheric pressure. Thereafter, it was cooled to room temperature, and the produced catalyst was recrystallized with 10 times the amount of acetone. The precipitate was filtered through filter paper and dried at 100 ° C. for 2 hours to obtain the target compound. Polycondensation catalyst A was prepared by adding ethylene glycol and water to this compound and adjusting the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1.
Reference Example 2 (Synthesis of polycondensation catalyst B)
While stirring a mixture of 99 parts by weight of ethylene glycol and 1 part by weight of acetic acid, 6 parts by weight of titanium tetrabutoxide was slowly added to prepare a transparent ethylene glycol solution of the titanium compound. The ethylene glycol solution of this titanium compound was added to an ethylene glycol solution of phenylphosphonic acid (2% by mass) stirred at a temperature of 100 ° C., and the molar ratio of titanium atoms in titanium tetrabutoxide to phosphorus atoms in phenylphosphonic acid was After slowly adding 1: 2, the mixture was stirred for 1 hour while maintaining the temperature at 100 ° C. to obtain a white slurry. Polycondensation catalyst B was prepared by adding ethylene glycol and water to this compound and adjusting the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1.
Reference Example 3 (Synthesis of polycondensation catalysts C to D)
Adjustment was performed in the same manner as in Reference Example 2 except that the phosphorus compound was changed as shown in Table 1.
Reference Example 4 (Synthesis of polycondensation catalyst E)
Titanium tetrabutoxide was added to an ethylene glycol solution (0.2% by mass) of trimellitic anhydride with respect to trimellitic anhydride in an amount of 1/2 mol, and the reaction was carried out for 60 minutes while maintaining at 80 ° C. under atmospheric pressure. Thereafter, it was cooled to room temperature, and the produced catalyst was recrystallized with 10 times the amount of acetone. The precipitate was filtered through filter paper and dried at 100 ° C. for 2 hours. The obtained compound was added to an ethylene glycol solution (2 mass%) of triethylphosphonoacetate and stirred at 120 ° C. for 60 minutes to obtain a white slurry. A polycondensation catalyst G was prepared by adding ethylene glycol and water to this compound and adjusting the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1.
Reference Example 5 (Synthesis of polycondensation catalysts F to G)
Adjustment was made in the same manner as in Reference Example 4 except that the phosphorus compound was changed as shown in Table 1.
Reference Example 6 (Synthesis of polycondensation catalysts H to I)
Adjustment was performed in the same manner as in Reference Example 1 except that the titanium compound and polyvalent carboxylic acid compound were changed as shown in Table 1.
Reference Example 7 (Synthesis of polycondensation catalyst J)
Titanium tetrabutoxide was added to an ethylene glycol solution (0.1% by mass) of citric acid with respect to citric acid, and the mixture was allowed to react for 60 minutes while maintaining at 50 ° C. under atmospheric pressure. After cooling to room temperature, ethylene glycol and water were further added to adjust the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1 and designated polycondensation catalyst J.
Reference Example 8 (Synthesis of polycondensation catalyst K)
Titanium tetrabutoxide was added to an ethylene glycol solution (0.1% by mass) of lactic acid in an amount of ½ mol with respect to lactic acid, and the reaction was carried out for 60 minutes while maintaining at 50 ° C. under atmospheric pressure. After cooling to room temperature, ethylene glycol and water were further added to adjust the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1 and designated polycondensation catalyst K.
Reference Example 9 (Synthesis of polycondensation catalyst L)
Adjustment was performed in the same manner as in Reference Example 1 except that the water content was changed as shown in Table 1.
Reference Example 10 (Synthesis of polycondensation catalyst M)
Polycondensation catalyst M was prepared by adding ethylene glycol and water to titanium tetrabutoxide and adjusting the titanium concentration and water concentration in the polycondensation catalyst solution as shown in Table 1.

Reference Example 11 (Measurement of visible light absorption spectrum of hue adjusting agent, preparation of hue adjusting agents A to H)
The hue adjusting dye is made into a chloroform solution having a concentration of 20 mg / L at room temperature, filled in a quartz cell having an optical path length of 1 cm, the control cell is filled with only chloroform, and 380 using a Hitachi spectrophotometer U-3010 type. A visible light absorption spectrum in a visible light region of ˜780 nm was measured. When two kinds of hue adjusting dyes were mixed, the total concentration was 20 mg / L. The ratio of the absorbance at each wavelength of 400, 500, 600, and 700 nm to the maximum absorption wavelength and the absorbance at that wavelength was measured. Furthermore, the thermal mass decrease start temperature of the dye for adjusting the hue of the powder was measured. In addition, when adding these hue regulators in the polyester production process in Examples and Comparative Examples, after adjusting ethylene glycol and water as described in Table 2, hue having a stirrer and a circulation line pipe It was dispersed in the container of the adjusting agent dissolution tank. Next, the internal temperature was heated to 140 ° C. and dissolved in about 1 hour, and then circulated at a flow rate of 20 m / min for 30 minutes. The moisture content of this hue adjusting agent preparation solution was measured by the above-described measuring method. The results are shown in Table 2.

Reference Example 12 (Creation of container)
<Container 1>
A polyethylene terephthalate sheet was formed by injection molding into a container having a thickness of 0.2 mm and an internal volume of 500 cm 3 and its lid, and an air vent was provided. The combined weight of the container and the lid was 10 g.
<Container 2>
A biaxially stretched polyethylene terephthalate film having a thickness of 0.07 mm was sewn using a polyethylene terephthalate fiber as a sewing thread, and a bag having an air volume of 500 cm3 was created. The weight of the container containing the film and thread was 3 g.
Example 1
In a reactor where 225 parts of bis (hydroxyethyl) terephthalate stays in advance, 179 parts of high-purity terephthalic acid (manufactured by Mitsui Chemicals, Inc.) was maintained under stirring and under a nitrogen atmosphere at 255 ° C. and normal pressure. And a slurry prepared by mixing 95 parts of ethylene glycol were supplied at a constant rate, and the esterification reaction was completed for 4 hours while water and ethylene glycol generated by the reaction were distilled out of the system to complete the reaction. . The esterification rate at this time was 98% or more, and the polymerization degree of the produced polyester oligomer was about 5 to 7.
225 parts of the oligomer obtained by this esterification reaction is transferred to a polycondensation reaction tank, and 10 mass ppm in terms of titanium atom with respect to the polymer from which polycondensation catalyst A is obtained, and 2 with respect to the polymer from which hue adjusting agent A is obtained. It poured so that it might become mass ppm. After 5 minutes, an ethylene glycol slurry of titanium oxide particles was added to the polymer in an amount of 0.15% by weight in terms of titanium oxide particles. After another 5 minutes, the reaction system was decompressed to initiate the reaction. The reaction temperature in the system is raised from 250 to 285 ° C, and the reaction pressure is raised and reduced in steps from normal pressure to 30 Pa, and the polycondensation reaction is carried out while removing water and ethylene glycol generated in the reaction from the outside of the system. It was. The time to reach the final temperature and final pressure was both 60 minutes. The progress of the polycondensation reaction is confirmed without monitoring the load on the stirring blades in the system, and when it reaches 92% of the predetermined stirring torque (2 hours and 20 minutes from the start of decompression) From the top of the reaction can, tetrakis (2,4-di-t-butyl-5-methylphenyl) [1,1-biphenyl] -4, equivalent to 1760 mass ppm (100 mass ppm in terms of phosphorus atom) with respect to the polymer 4′-Diylbisphosphonite (Osaki Kogyo Co., Ltd.) was added after filling the container 1. Thereafter, the reaction is continued, and when the predetermined stirring torque is reached, the reaction system is purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged in the form of a strand, cooled, and immediately cut, and about 3 mm About granular pellets were obtained. The time from the start of decompression to the arrival of the predetermined stirring torque was 159 minutes. Table 3 shows the measurement results of the physical properties of the obtained polymer. The obtained polymer was excellent in hue and also had a small Δb value 290 and excellent thermal stability.
Further, this polyester was vacuum-dried at 150 ° C. for 12 hours to make the moisture content in the range of 10 to 50 ppm by mass and then supplied to an extruder type spinning machine. The spinning temperature was 285 ° C., the pore diameter was 0.18 mmφ, and the number of holes was 16 The material was discharged from the spinneret and taken up at a spinning speed of 1000 m / min to prepare a 300 dtex / 36 filament. In the melt spinning process, almost no deposits around the nozzle holes and no increase in filtration pressure were observed during spinning.
Examples 2-13
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the polycondensation catalyst was changed as shown in Table 3. In Examples 12 and 13, the hue b value was slightly poor, and the thermal stability was slightly inferior. Almost no deposits and no increase in filtration pressure were observed around the nozzle holes during spinning.
Examples 14-15
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the addition amount of the polycondensation catalyst was changed as shown in Table 3. In Example 14, the polymerization time was long, and the obtained polymer had a slightly poor hue. In Example 15, a polymer having slightly inferior thermal stability was obtained. Further, the deposit around the base hole during spinning and the increase in the filtration pressure were slightly contaminated and broken in Example 15, but at a level that would not interfere with the operation.

Examples 16-22
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the hue adjusting agent was changed as shown in Table 4. In Example 19, although the hue was slightly bad, it was at a level with no problem on the product. In Examples 20 to 22, a slight amount of deposit was observed around the die hole during spinning, but this was at a level that would not interfere with operation. In other examples, the hue and thermal stability were both good, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.
Examples 23-24
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the addition amount of the hue adjusting agent was changed as shown in Table 4. In Examples 23 and 24, although the obtained polymers had a slightly poor hue, the thermal stability was good, and deposits around the die holes during spinning and an increase in filtration pressure were hardly observed.
Examples 25-31
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the phosphorus compounds were changed as shown in Table 4. The obtained polymer was good in hue and thermal stability, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.
Examples 32-33
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the addition amount of the phosphorus compound was changed as shown in Table 4. In Example 32, a polymer having slightly inferior thermal stability was obtained. In Example 33, a slight amount of deposit was observed around the die hole during spinning, but this was at a level that would not interfere with operation.

Examples 34-36
In Example 34, the addition of the phosphorus compound was added to the container 2, and in Example 35, the phosphorus compound was added after adjusting to an ethylene glycol (10% by mass) solution having a water content of 0.15% by mass. In 36, polyester was polymerized and melt-spun in the same manner as in Example 1 except that the phosphorus compound alone was added to the polymerization reactor. In Examples 35 and 36, polymers having slightly inferior thermal stability were obtained, but in other examples, both hue and thermal stability were good, and deposits and filtration pressure around the mouthpiece hole at the time of spinning Little increase was observed.
Examples 37-38
Polyester was polymerized and melt-spun in the same manner as in Example 1 except that the timing of adding the phosphorus compound was changed as shown in Table 5. In Example 37, the polymerization time was long, and the resulting polymer had a slightly poor hue. In Example 38, deposits around the die holes during spinning were observed, but this was at a level that would not interfere with operation.
Examples 39-42
The phosphorus compound shown in Table 5 is adjusted to an ethylene glycol (2% by mass) solution having a water content of 0.15% by mass with respect to the polymer obtained by converting 50 mass ppm in terms of phosphorus atom, and the oligomer after the esterification reaction is used. After adding to the polycondensation reaction tank and before adding the polycondensation catalyst, except that 50 mass ppm in terms of phosphorus atom was added to the obtained polymer at 92% of the predetermined stirring torque, Polyester was polymerized and melt-spun as in Example 1. In Examples 39 to 42, the polymerization time was long, and the obtained polymer had a slightly poor hue. In addition, almost no deposits and increase in filtration pressure around the nozzle holes during spinning were observed.
Examples 43-45
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the antioxidants listed in Table 5 were added. The obtained polymer was good in hue and thermal stability, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.
Examples 46-47
Except for changing the setting of the predetermined agitation torque (in Example 46, the intrinsic viscosity of the resulting polyester is lowered, in Example 47, the intrinsic viscosity of the obtained polyester is increased), the same as in Example 1. Polyester was polymerized and melt spun. In Examples 46 and 47, although the obtained polymer had a slightly poor hue, the thermal stability was good, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.

Example 48
To a mixture of 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol, 10 mass ppm in terms of titanium atom was added to the polymer from which the polycondensation catalyst A was obtained, and charged into a SUS container capable of pressure reaction. The ester exchange reaction was carried out while increasing the pressure from 140 ° C. to 240 ° C. under a pressure of 0.07 MPa, and then triethylphosphonoacetate was added to complete the ester exchange reaction.
The oligomer obtained by the transesterification reaction was transferred to a polycondensation reaction tank, and charged to 2 mass ppm with respect to the polymer from which the hue adjusting agent A was obtained. After 5 minutes, an ethylene glycol slurry of titanium oxide particles was added to the polymer in an amount of 0.15% by weight in terms of titanium oxide particles. After another 5 minutes, the reaction system was decompressed to initiate the reaction. The reaction temperature in the system is raised from 250 to 285 ° C, and the reaction pressure is gradually increased and reduced from normal pressure to 40 Pa, respectively, and the polycondensation reaction is performed while removing water and ethylene glycol generated in the reaction out of the system. It was. The time to reach the final temperature and final pressure was both 60 minutes. The progress of the polycondensation reaction is confirmed without monitoring the load on the stirring blades in the system, and when it reaches 90% of the predetermined stirring torque (2 hours and 30 minutes after starting decompression) Then, triethylphosphonoacetate equivalent to 880 mass ppm (50 mass ppm in terms of phosphorus atom) with respect to the polymer obtained from the upper part of the reaction can was packed into the container 1 and added. Thereafter, the reaction is continued, and when the predetermined stirring torque is reached, the reaction system is purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged in the form of a strand, cooled, and immediately cut, and about 3 mm About granular pellets were obtained. The time from the start of decompression to the arrival of the predetermined stirring torque was 166 minutes. Table 6 shows the measurement results of the physical properties of the obtained polymer. The obtained polymer was excellent in hue and also had a small Δb value 290 and excellent thermal stability.
Further, this polyester was vacuum-dried at 150 ° C. for 12 hours to make the moisture content in the range of 10 to 50 ppm by mass and then supplied to an extruder type spinning machine. The spinning temperature was 285 ° C., the pore diameter was 0.18 mmφ, and the number of holes was 16 The material was discharged from the spinneret and taken up at a spinning speed of 1000 m / min to prepare a 300 dtex / 36 filament. In the melt spinning process, almost no deposits around the nozzle holes and no increase in filtration pressure were observed during spinning.
Examples 49-57
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the polycondensation catalyst was changed as shown in Table 6. In Examples 56 and 57, the hue b value was slightly poor, and the thermal stability was slightly inferior. Almost no deposits and no increase in filtration pressure were observed around the nozzle holes during spinning.

Examples 58-64
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the hue adjusting agent was changed as shown in Table 7. In Example 61, although the hue was slightly bad, it was at a level with no problem on the product. In Examples 62 to 64, a slight amount of deposit was observed around the mouthpiece hole during spinning, but this was at a level that would not interfere with operation. In other examples, the hue and thermal stability were both good, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.
Examples 65-70
Polyester was polymerized and melt-spun in the same manner as in Example 48 except that the phosphorus compounds were changed as shown in Table 7. The obtained polymer was good in hue and thermal stability, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.

Examples 71-74
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the addition of the phosphorus compound was changed as shown in Table 8. In Example 71, the obtained polymer was slightly poor in hue and slightly inferior in thermal stability. In Examples 72 and 74, deposits around the die holes during spinning were observed, but at a level that would not interfere with operation.
Examples 75-76
In Example 75, the addition of the phosphorus compound to be added after starting the pressure reduction was added after adjusting to an ethylene glycol (10% by mass) solution having a water content of 0.15% by mass. In Example 76, the phosphorus compound was used alone. A polyester was polymerized and melt-spun in the same manner as in Example 48 except that it was added to the polymerization reactor. In Examples 75 and 76, polymers having slightly inferior thermal stability were obtained. In the other examples, both hue and thermal stability were good. Little increase was observed.
Example 77
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the antioxidants listed in Table 8 were added. The obtained polymer was good in hue and thermal stability, and deposits around the mouthpiece hole during spinning and almost no increase in filtration pressure were observed.

Reference Example 12 (Synthesis of polycondensation catalyst N, O, P, Q, R)
Adjustments were made in the same manner as in Reference Examples 1, 4, and 5 except that the moisture content and the titanium concentration in the polycondensation catalyst solvent were changed as shown in Table 9.

Reference Example 13 (Preparation of hue adjusting agents I, J, K)
Adjustments were made in the same manner as in Reference Example 11 except that the moisture content and hue adjusting agent preparation concentration were changed as shown in Table 10.

Comparative Example 1
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that no phosphorus compound was added. The hue was a polymer having a strong yellowish color and poor thermal stability.
Comparative Examples 2-6
A polyester was polymerized and melt-spun in the same manner as in Example 1 except that the polycondensation catalyst was changed as shown in Table 11. In Comparative Examples 2 to 5, the obtained polymer had a strong yellowish hue and was inferior in thermal stability. Further, the polymer obtained in Comparative Example 6 was a polymer having good hue and thermal stability, but deposits were observed around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage.
Comparative Examples 7-10
In Comparative Examples 7 to 9, polyester was polymerized and melt-spun in the same manner as in Example 1 except that the hue adjusting agent was changed as shown in Table 11. In Comparative Examples 7 to 9, the obtained polymers had good hue and thermal stability, but deposits were observed around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage. In Comparative Example 10, a polyester was polymerized and melt-spun in the same manner as in Example 1 except that no hue adjusting agent was added. It was a strong yellowish polymer inferior in hue.
Comparative Examples 11-12
Comparative Example 11 was prepared by adding 300 mass ppm in terms of antimony atoms to a polymer capable of obtaining antimony trioxide as a polycondensation catalyst in an ethylene glycol (2 mass%) solution having a water content of 0.15 mass%. In the same manner as in Example 1, the polyester was polymerized and melt-spun. The obtained polymer had good hue and thermal stability, but deposits were observed around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage. Moreover, in Comparative Example 12, 50 mass ppm in terms of cobalt atom is added to an ethylene glycol (2 mass%) solution having a water content of 0.15 mass% for the polymer from which cobalt acetate can be obtained instead of the hue modifier. A polyester was polymerized and melt-spun in the same manner as in Example 1 except that. The obtained polymer was a polymer having low hue brightness and poor thermal stability.

Comparative Example 13
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the phosphorus compound added after the start of the polycondensation reaction was not added. The hue was a polymer having a strong yellowish color and poor thermal stability.
Comparative Examples 14-18
A polyester was polymerized and melt-spun in the same manner as in Example 48 except that the polycondensation catalyst was changed as shown in Table 12. In Comparative Examples 14 to 17, the hues of the obtained polymers were strongly yellowish and poor in heat stability. Further, the polymer obtained in Comparative Example 18 was a polymer having good hue and thermal stability, but deposits were observed around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage.
Comparative Examples 19-22
In Comparative Examples 19 to 21, polyester was polymerized and melt-spun in the same manner as in Example 48 except that the hue adjusting agent was changed as shown in Table 12. In Comparative Examples 19 to 21, the obtained polymers had good hue and thermal stability, but deposits were seen around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage. In Comparative Example 22, polyester was polymerized and melt-spun in the same manner as in Example 48 except that no hue adjusting agent was added. It was a strong yellowish polymer inferior in hue.
Comparative Examples 23-24
In Comparative Example 23, 40 mass ppm in terms of cobalt atom was added to a polymer capable of obtaining cobalt acetate instead of the polycondensation catalyst A as a transesterification reaction catalyst, and antimony trioxide was obtained as a polycondensation catalyst. Except that 300 mass ppm in terms of antimony atom was adjusted to an ethylene glycol (2 mass%) solution with a water content of 0.15 mass% and added after transferring the oligomer to the polycondensation reaction tank after completion of the transesterification reaction. In the same manner as in Example 48, the polyester was polymerized and melt-spun. The obtained polymer was a polymer having low hue brightness and inferior thermal stability, and deposits were observed around the mouthpiece holes during melt spinning, resulting in increased filtration pressure and breakage. In Comparative Example 24, 40 mass ppm in terms of cobalt atom is added to a polymer that can obtain cobalt acetate instead of the polycondensation catalyst A as a transesterification reaction catalyst, and a polymer that can obtain the polycondensation catalyst A as a polycondensation catalyst. Polyester was polymerized and melt-spun in the same manner as in Example 48 except that 10 mass ppm in terms of titanium atom was added after the transesterification reaction and the oligomer was transferred to the polycondensation reaction tank. The obtained polymer was a polymer having low hue brightness and poor thermal stability.

Claims (13)

In a method for producing a polyester by subjecting a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative to an esterification or transesterification reaction and then performing a polycondensation reaction under reduced pressure in the polymerization reactor, the formula ( Titanium compound prepared as an alkylene glycol solution satisfying 1) and (2) and a hue adjusting agent prepared as an alkylene glycol solution satisfying formulas (3) and (4) until the polyester reaches a target degree of polymerization. A method for producing a polyester, characterized in that a phosphorus compound is added between the start of pressure reduction in the polymerization reactor and the time when the polyester reaches a target degree of polymerization.
(1) 0.1 ≦ T / W _T ≦ 1.5
(2) 0.01 ≦ W _T ≦ 1.0
(3) 0.01 ≦ C / W _C ≦ 1.0
(4) 0.01 ≦ W _C ≦ 1.0
[T: Titanium atom concentration (wt%) in the alkylene glycol preparation solution of the titanium compound, W _T : Water content (wt%) in the alkylene glycol preparation solution of the titanium compound, C: In the alkylene glycol preparation solution of the hue adjusting agent Hue adjusting agent concentration (wt%), W _C : Water content (wt%) in the alkylene glycol preparation solution of the hue adjusting agent] The titanium compound is a compound represented by the general formula (I) or a product obtained by reacting the compound represented by the general formula (I) with the aromatic polyvalent carboxylic acid or anhydride represented by the general formula (II). The method for producing a polyester according to claim 1, wherein:

[In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 10 carbon atoms or a phenyl group, p represents an integer of 1 to 4, and p Is 2, 3 or 4, 2, 3 or 4 R ² and R ³ may be different from each other. ]

[In formula (II), q represents the integer of 2-4. ] The titanium compound is a product obtained by reacting a compound represented by the general formula (I) with at least one phosphorus compound represented by the general formula (III), (IV), or (V). The method for producing a polyester according to claim 1.

[In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 10 carbon atoms or a phenyl group, p represents an integer of 1 to 4, and p Is 2, 3 or 4, 2, 3 or 4 R ² and R ³ may be different from each other. ]

[In the formula (III), r represents 1 or 2, s represents 0 or 1, provided that the sum of r and s is 1 or 2, and R ⁵ represents an unsubstituted or substituted 6 Represents an aryl group having -20 carbon atoms, or an alkyl group having 1-20 carbon atoms, and when r represents 2, the two R ⁵ groups may be identical to each other, or May be different. In the formula (IV), u and v are integers of 1 to 3, t is an integer of 2 or more, and R ⁶ is an unsubstituted or substituted aryl group having 6 to 20 carbon atoms, or Represents an alkyl group having 1 to 20 carbon atoms. In formula (V), R ⁷ and R ⁸ represent the same or different alkyl groups having 1 to 4 carbon atoms, and X represents —CH 2 — or —CH (Y) —. ] A product obtained by reacting a compound represented by general formula (I) with an aromatic polyvalent carboxylic acid or anhydride represented by general formula (II), a general formula (III), (IV), The method for producing a polyester according to claim 1, wherein the product is a product obtained by reacting at least one of the phosphorus compounds represented by (V).

[In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 10 carbon atoms or a phenyl group, p represents an integer of 1 to 4, and p Is 2, 3 or 4, 2, 3 or 4 R ² and R ³ may be different from each other. ]

[In formula (II), q represents the integer of 2-4. ]

[In the formula (III), r represents 1 or 2, s represents 0 or 1, provided that the sum of r and s is 1 or 2, and R ⁵ represents an unsubstituted or substituted 6 Represents an aryl group having -20 carbon atoms, or an alkyl group having 1-20 carbon atoms, and when r represents 2, the two R ⁵ groups may be identical to each other, or May be different. In the formula (IV), u and v are integers of 1 to 3, t is an integer of 2 or more, and R ⁶ is an unsubstituted or substituted aryl group having 6 to 20 carbon atoms, or Represents an alkyl group having 1 to 20 carbon atoms. In formula (V), R ⁷ and R ⁸ represent the same or different alkyl groups having 1 to 4 carbon atoms, and X represents —CH 2 — or —CH (Y) —. ] 2. The method for producing a polyester according to claim 1, wherein the titanium compound is a titanium complex compound having at least one selected from the group consisting of polyvalent carboxylic acid, hydroxycarboxylic acid, and nitrogen-containing carboxylic acid as a chelating agent. . The hue adjusting agent is a hue adjusting agent having a mass decrease starting temperature of 250 ° C. or higher when measured with a thermobalance in a nitrogen atmosphere under a temperature rising rate of 10 ° C./min, and having a concentration of 20 mg / L chloroform. When a visible light absorption spectrum in a wavelength range of 380 to 780 nm was measured for a solution at an optical path length of 1 cm, the maximum absorption wavelength was in the range of 540 to 650 nm, and the ratio of the absorbance at each wavelength to the absorbance at the maximum absorption wavelength was expressed by a mathematical formula. The method for producing a polyester according to any one of claims 1 to 5, wherein all of (5) to (8) are satisfied.
(5) 0.00 ≦ A400 / Amax ≦ 0.20
(6) 0.10 ≦ A500 / Amax ≦ 0.70
(7) 0.55 ≦ A600 / Amax ≦ 1.00
(8) 0.00 ≦ A500 / Amax ≦ 0.05
[In the formulas (5) to (8), A400, A500, A600 and A700 represent the absorbance in the visible light absorption spectrum at wavelengths of 400 nm, 500 nm, 600 nm and 700 nm, respectively, and Amax represents the absorbance in the visible light absorption spectrum at the maximum absorption wavelength. Represents absorbance. ] The hue adjusting agent uses a blue color adjusting dye and a purple color adjusting dye in a mass ratio of 90:10 to 40:60 in combination. A method for producing polyester. The hue adjusting agent uses a blue color adjusting dye and a red or orange color adjusting dye in a mass ratio of 98: 2 to 80:20 in combination. The manufacturing method of polyester as described in claim | item. One or more selected from a phosphite compound, a phosphate compound, a phosphonite compound, a phosphonate compound, a phosphinate compound, and a phosphinate compound during the period from the start of the pressure reduction in the polymerization reactor until the polyester reaches the target degree of polymerization. The method for producing a polyester according to claim 1, wherein 1 to 10000 mass ppm is added in total to the obtained polyester in terms of phosphorus atoms. A method for producing a polyester according to any one of claims 1 to 9, wherein a phenolic antioxidant is added. The polyester produced by the method according to any one of claims 1 to 10, wherein the content of the metal element having a true specific gravity of 5.0 or more is 0 to 10 ppm by mass. The polyester produced by the method according to any one of claims 1 to 10, wherein the residual ratio of the hue adjusting agent in the polymer is 50 to 100%. The fiber which uses the polyester manufactured by the method of any one of Claims 1-10.