JP2023082298A - Method for producing polyester - Google Patents

Abstract

To provide a new method for producing polyester that can suppress heat generation in a polymerization reaction and, furthermore, can reduce chlorine content in the resultant polyester.SOLUTION: The present invention provides a method for producing polyester by an interfacial polymerization reaction using divalent phenol and carboxylic acid dichloride as raw material. The method includes gradually adding a solution (B) comprising the carboxylic acid dichloride and a terminator to a mixture (A) comprising the divalent phenol and a catalyst.SELECTED DRAWING: None

Description

The present invention relates to a method for producing polyester.

Polyesters are mainly produced by a transesterification method, a solution polymerization method, an interfacial polymerization method, or the like. Among them, the interfacial polymerization method has the advantage of easily obtaining a polyester having a high molecular weight and a high glass transition temperature. In the production of polyester by the interfacial polymerization method, for example, an aqueous phase obtained by dissolving a dihydric phenol in an alkaline aqueous solution and an organic phase obtained by dissolving a dihydric carboxylic acid chloride in a water-insoluble organic solvent are mixed in the presence of a catalyst. (Patent Documents 1 to 3).

However, since the reaction between the water phase and the organic phase described above is accompanied by rapid heat generation, it has sometimes been necessary to introduce cooling equipment. again. When an alkaline aqueous solution containing a dihydric phenol and a solution of a carboxylic acid chloride dissolved in an organic solvent are reacted in the presence of a terminal terminator, a large amount of chlorine derived from the carboxylic acid chloride is contained in the polyester. sometimes occurred.

Japanese Patent Publication No. 48-55284 WO2014/115694 WO2014/115746

There has been a demand for the development of a new polyester production method that can suppress heat generation during the polymerization reaction and, in particular, can reduce the chlorine content in the resulting polyester.

The present inventors have made intensive studies to solve the above problems, and found that the above problems can be solved by reacting a specific component with a specific component by a specific addition method during the interfacial polymerization reaction. I found that I could do it, and completed the present invention. That is, the present invention is as follows.
<1> A method for producing a polyester by an interfacial polymerization reaction using a dihydric phenol and a carboxylic acid dichloride as raw materials,
A method for producing a polyester, wherein the solution (B) containing the carboxylic acid dichloride and the terminal terminator is sequentially added to the mixture (A) containing the dihydric phenol and the catalyst.
<2> The method for producing polyester according to <1> above, wherein the mixture (A) further contains an organic solvent, an alkali metal compound and water.
<3> The method for producing a polyester according to <1> or <2> above, wherein the solution (B) further contains an organic solvent.
<4> The method for producing a polyester according to any one of <1> to <3>, wherein the sequential addition is continuous addition.
<5> The method for producing a polyester according to any one of <1> to <4>, wherein the sequential addition time is 5 minutes or longer.
<6> The method for producing polyester according to any one of <1> to <5> above, wherein the method for producing polyester is a batch system.

A polyester with a reduced chlorine content can be stably produced by the method for producing a polyester of the present invention.

The present invention will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the invention's effects.

The present invention is a method for producing a polyester by an interfacial polymerization reaction using a dihydric phenol and a carboxylic acid dichloride as raw materials, wherein a mixture (A) containing the dihydric phenol and a catalyst is added with the carboxylic acid dichloride and terminal termination. A polyester production method in which a solution (B) containing an agent is sequentially added.
As used herein, the term "sequential addition" means adding the entire amount little by little over a period of 1 minute or longer, rather than adding the entire amount at once or within a short period of time.
A preferred embodiment of the present invention is a mixture (A) further containing an organic solvent, an alkali metal compound and water in addition to the dihydric phenol and the catalyst, and a solution further containing an organic solvent in addition to the carboxylic acid dichloride and the terminal terminator. This is a method for producing a polyester in which (B) is added sequentially.
In general, an interfacial polymerization reaction is carried out by continuously mixing an aqueous phase and an organic phase in a tubular reactor or a multistage tank reactor. Such a method requires a continuous supply of raw materials and is suitable for mass production. Among interfacial polymerization reactions, the present invention is suitable for batch reactions.
The batch-type reaction is a reaction in which the polymerization reaction is completed in a single reactor, and the target polyester is obtained by controlling the molecular weight with a terminal terminator at the interface between the aqueous phase and the organic phase. be.

<Dihydric phenol>
In the present invention, the dihydric phenol includes, for example, 1,1'-biphenyl-4,4'-diol, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl ) sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A; BPA), 2,2- Bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z; BPZ), 1,1-bis (4-hydroxyphenyl) cyclododecane, 2,2-bis ( 4-hydroxyphenyl)hexafluoropropane, 4,4′-[1,3-phenylenebis(1-methylethylidene)]bisphenol, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2 , 2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl ) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane (bisphenol C; BPC), 2,2-bis ( 4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 9,9-bis(4-hydroxyphenyl) Fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 2,2-bis(4-hydroxy-3-polydimethylpropylphenyl)propane, bis(4-hydroxyphenyl)ether, bis(4 -hydroxy-3-methylphenyl) ether, bis(4-hydroxy-3-ethylphenyl) ether, bis(4-hydroxy-3-t-butylphenyl) ether, bis(4-hydroxy-3-allylphenyl) ether , bis(2-hydroxyphenyl) ether, bis(4-hydroxy-3,5-dimethylphenyl) ether, bis(4-hydroxy-3-fluorophenyl) ether, bis(4-hydroxy-3-phenylphenyl) ether , α,ω-bis[2-(p-hydroxyphenyl)ethyl]polydimethylsiloxane, α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane, α,ω-bis[3-( 4-hydroxy-3-methoxyphenyl)propyl]polydimethylsiloxane, α,ω-bis[3-(p-hydroxyphenyl)propyl]polydimethylsiloxane, α,ω-bis[2-methyl-2-(p- Hydroxyphenyl)ethyl]polydimethylsiloxane and the like can be used. Among these, preferably 2,2-bis(4-hydroxyphenyl)propane (bisphenol A; BPA), 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z; BPZ), 2 , 2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C; BPC). These may be used alone or in combination of two or more.

一般式（１）中、Ｒ_３及びＲ_４は、各々独立に、水素、フッ素、塩素、臭素、ヨウ素、それぞれ置換基を有してもよい、炭素数１～２０のアルキル基、炭素数６～１２のアリール基、炭素数２～１２のアルケニル基、炭素数１～５のアルコキシ基、又は炭素数７～１７のアラルキル基である。ｐ及びｑは、各々独立に、０～２の整数を表す。ｐ及びｑは、好ましくは、各々独立に０または１である。Ｘは、 In the present invention, an aromatic dihydroxy compound represented by the following general formula (1) may be used as the dihydric phenol.

In general formula (1), R ₃ and R ₄ each independently represent hydrogen, fluorine, chlorine, bromine, iodine, an optionally substituted alkyl group having 1 to 20 carbon atoms, and 6 carbon atoms. 1 to 12 aryl groups, alkenyl groups having 2 to 12 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, or aralkyl groups having 7 to 17 carbon atoms. p and q each independently represents an integer of 0 to 2; p and q are preferably each independently 0 or 1; X is

のいずれかを表し、ここで、Ｒ_５及びＲ_６は、各々独立に、水素、フッ素、塩素、臭素、ヨウ素、各々置換基を有してもよい、炭素数１～２０のアルキル基、炭素数１～５のアルコキシ基、又は炭素数６～１２アリール基を表すか、Ｒ_５とＲ_６が結合して、炭素数５～２０の炭素環または元素数５～１２の複素環を形成する基を表す。Ｒ_７及びＲ_８は、各々独立に、水素、フッ素、塩素、臭素、ヨウ素、各々置換基を有してもよい、炭素数１～９のアルキル基、炭素数１～５のアルコキシ基、炭素数２～１２のアルケニル基、又は炭素数６～１２アリール基を表す。Ｒ_９は、置換基を有してもよい炭素数１～９のアルキレン基である。ｂは０～２０の整数を表し、ｃは１～５００の整数を表す。

wherein R ₅ and R ₆ are each independently hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 20 carbon atoms each optionally having a substituent, carbon represents an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, or R ₅ and R ₆ combine to form a carbocyclic ring having 5 to 20 carbon atoms or a heterocyclic ring having 5 to 12 elements; represents a group. R ₇ and R ₈ are each independently hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, each optionally having a substituent, carbon It represents an alkenyl group having 2 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ₉ is an optionally substituted alkylene group having 1 to 9 carbon atoms. b represents an integer of 0-20 and c represents an integer of 1-500.

Specific examples of the aromatic dihydroxy compound represented by the general formula (1) may overlap with those already mentioned above as specific examples of the dihydric phenol, but 4,4′-biphenyldiol, bis( 4-hydroxyphenyl)methane, bis(2-hydroxyphenyl)methane, 2,4'-dihydroxydiphenylmethane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(2-hydroxyphenyl)sulfone , bis(4-hydroxy-3-methylphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxy phenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4 -hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)ethane, bis(4-hydroxy-3-methylphenyl)methane, 2,2-bis(4-hydroxy- 3-t-butylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxy-3-methylphenyl) Cyclohexane, 1,1-bis(4-hydroxyphenyl)cycloundecane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 2,2-bis(4-hydroxy-3-allylphenyl)propane, 3,3 ,5-trimethyl-1,1-bis(4-hydroxyphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl) Fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethyldiphenyl random copolymerized siloxane, α,ω-bis[3-(o- Hydroxyphenyl)propyl]polydimethylsiloxane, 4,4′-[1,4-phenylenebis(1-methylethylidene)]bisphenol, 4,4′-[1,3-phenylenebis(1-methylethylidene)]bisphenol , adamantane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexane, 1,1-bis(4-hydroxyphenyl)-2-methylpropane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)decane, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 2 , 2-bis(4-hydroxyphenyl)hexafluoropropane and the like. Two or more of these can be used in combination. Also among these, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, and 2,2-bis(4-hydroxy-3- Methylphenyl)propane is preferred.

<Carboxylic acid dichloride>
Examples of the carboxylic acid dichloride in the present invention include dichlorides of dicarboxylic acids listed below. Dicarboxylic acids include adipic acid, suberic acid, sebacic acid, diphenic acid, phthalic acid, isophthalic acid, terephthalic acid, 4,4′-dicarboxylic acid, 3-tert-butylisophthalic acid, and toluene-2,5-dicarboxylic acid. , p-xylene-2,5-dicarboxylic acid, pyridine-2,3-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine- 3,4-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, biphenyl-2,2'- dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, diphenyl ether-2,2'-dicarboxylic acid, diphenyl ether-2,3'-dicarboxylic acid, diphenyl ether-2,4'-dicarboxylic acid, diphenyl ether-3,3'- dicarboxylic acid, diphenyl ether-3,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, bis(4-carboxy-3-methylphenyl) ether, bis(4-carboxy-2-methylphenyl) ether, bis (4-carboxy-3-ethylphenyl) ether, bis(4-carboxy-2-ethylphenyl) ether, bis(2-carboxy-3-methylphenyl) ether, bis(2-carboxy-4-methylphenyl) ether , bis(2-carboxy-5-methylphenyl) ether, bis(2-carboxy-6-methylphenyl) ether, bis(2-carboxy-3-ethylphenyl) ether, bis(2-carboxy-4-ethylphenyl) ) ether, bis(2-carboxy-5-ethylphenyl) ether, bis(2-carboxy-6-ethylphenyl) ether, bis(3-carboxy-2-methylphenyl) ether, bis(3-carboxy-4- methylphenyl) ether, bis(3-carboxy-5-methylphenyl) ether, bis(3-carboxy-6-methylphenyl) ether, bis(3-carboxy-2-ethylphenyl) ether, bis(3-carboxy- 4-ethylphenyl)ether, bis(3-carboxy-5-ethylphenyl)ether, bis(3-carboxy-6-ethylphenyl)ether and the like. Among these, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, biphenyl-2,2′-dicarboxylic acid, Biphenyl-4,4'-dicarboxylic acid, diphenyl ether-2,2'-dicarboxylic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, bis(4-carboxy-3-methylphenyl ) ether, bis(4-carboxy-2-methylphenyl) ether, bis(2-carboxy-3-methylphenyl) ether, bis(2-carboxy-4-methylphenyl) ether, bis(2-carboxy-5- methylphenyl) ether, bis(2-carboxy-6-methylphenyl) ether, bis(3-carboxy-2-methylphenyl) ether, bis(3-carboxy-4-methylphenyl) ether, bis(3-carboxy- 5-methylphenyl) ether, bis(3-carboxy-6-methylphenyl) ether, and a dicarboxylic acid that can be particularly preferably used is a mixture of equal amounts of terephthalic acid and isophthalic acid. These may be used alone or in combination of two or more.

一般式（２）中のｎは２、３、４のいずれかを示し、Ｙはエチル基、プロピル基、ブチル基又はベンジル基を示し、ＸはＣｌ、Ｂｒ、ＯＨ、又はＨＳＯ_４を表す。

一般式（２）’中のＹはブチル基又はベンジル基を示し、ＸはＣｌ、Ｂｒ、ＯＨ、又はＨＳＯ_４を表す。
具体的には、トリエチルベンジルアンモニウムクロライド、トリエチルベンジルアンモニウムブロマイド、トリエチルベンジルアンモニウムヒドロキサイド、トリエチルベンジルアンモニウムハイドロジェンサルフェート、テトラエチルアンモニウムクロライド、テトラエチルアンモニウムブロマイド、テトラエチルアンモニウムヒドロキサイド、テトラエチルアンモニウムハイドロジェンサルフェート、トリプロピルベンジルアンモニウムクロライド、トリプロピルベンジルアンモニウムブロマイド、トリプロピルベンジルアンモニウムヒドロキサイド、トリプロピルベンジルアンモニウムハイドロジェンサルフェート、テトラプロピルアンモニウムクロライド、テトラプロピルアンモニウムブロマイド、テトラプロピルアンモニウムヒドロキサイド、テトラプロピルアンモニウムハイドロジェンサルフェート、トリｎ－ブチルベンジルアンモニウムクロライド、トリｎ－ブチルベンジルアンモニウムブロマイド、トリｎ－ブチルベンジルアンモニウムヒドロキサイド、トリｎ－ブチルベンジルアンモニウムハイドロジェンサルフェート、テトラｎ－ブチルアンモニウムクロライド、テトラｎ－ブチルアンモニウムブロマイド、テトラｎ－ブチルアンモニウムヒドロキサイド、テトラｎ－ブチルアンモニウムハイドロジェンサルフェートが挙げられる。
これらは、単独で用いても複数併用することも可能である。また、トリエチルアミンやピリジンのような３級アミンと併用することも可能である。 <Catalyst>
Preferred catalysts used in the present invention include quaternary ammonium salts having a chemical structure represented by the following general formula (2). Further, quaternary ammonium salts having a chemical structure represented by the following general formula (2)' are also preferred.

n in the general formula (2) represents 2, 3 or 4, Y represents an ethyl group, propyl group, butyl group or benzyl group, and X represents Cl, Br, OH or _HSO4 .

Y in general formula (2)' represents a butyl group or a benzyl group, and X represents Cl, Br, OH, or _HSO4 .
Specifically, triethylbenzylammonium chloride, triethylbenzylammonium bromide, triethylbenzylammonium hydroxide, triethylbenzylammonium hydrogen sulfate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium hydrogen sulfate, tripropylbenzyl ammonium chloride, tripropylbenzylammonium bromide, tripropylbenzylammonium hydroxide, tripropylbenzylammonium hydrogen sulfate, tetrapropylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrapropylammonium hydrogen sulfate, tri-n- Butylbenzylammonium chloride, tri-n-butylbenzylammonium bromide, tri-n-butylbenzylammonium hydroxide, tri-n-butylbenzylammonium hydrogen sulfate, tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butyl ammonium hydroxide, tetra-n-butylammonium hydrogensulfate;
These can be used singly or in combination. It can also be used in combination with a tertiary amine such as triethylamine or pyridine.

<End terminator>
In the present invention, examples of terminal terminating agents include phenol, p-cresol, o-cresol, 2,4-xylenol, p-t-butylphenol, o-allylphenol, p-allylphenol, p-hydroxystyrene, p- Hydroxy-α-methylstyrene, p-propylphenol, p-cumylphenol, p-phenylphenol, o-phenylphenol, p-trifluoromethylphenol, p-nonylphenol, p-dodecylphenol, eugenol and other monovalent Phenols, benzoic acid chloride, methanesulfonyl chloride, monovalent acid chlorides such as phenylchloroformate, and the like. These may be used alone or in combination of two or more.

<Alkali metal compound>
Lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred as the alkali metal compound used in preferred embodiments of the present invention. These may be used alone or in combination of two or more.

<Organic solvent>
Specific examples of organic solvents used in preferred embodiments of the present invention include dichloromethane (methylene chloride), 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1,2,2-tetrachloroethane, 1 , 1,1-trichloroethane, o-dichlorobenzene, m-dichlorobenzene and p-dichlorobenzene; aromatic hydrocarbons such as toluene, benzene and xylene; and tetrahydrofuran. These may be used alone or in combination of two or more.

In a preferred embodiment of the present invention, the mixture (A) is obtained, for example, by mixing an organic solvent, a dihydric phenol, a catalyst, and an alkaline aqueous solution prepared separately.
An alkaline aqueous solution is obtained by mixing an alkali metal compound such as lithium hydroxide, sodium hydroxide, potassium hydroxide, etc. with water. The concentration of the alkaline aqueous solution is preferably 0.1-10 w/w%, more preferably 1.0-5.0 w/w%.

In a preferred embodiment of the present invention, solution (B) is obtained, for example, by mixing a carboxylic acid dichloride and a terminal terminator with an organic solvent.
In another preferred embodiment of the present invention, as the solution (B), a solution (B-1) in which a carboxylic acid dichloride and an organic solvent are mixed and a solution (B-2) in which a terminal terminator and an organic solvent are mixed are separated. It may be adjusted.

In a preferred embodiment of the invention, both mixture (A) and solution (B) contain an organic solvent. A certain amount of organic solvent (dichloromethane, etc.) is required to turn the polymer produced by polymerization into a polymer solution with an appropriate viscosity. It will drip and it will take time. On the other hand, if there is no organic solvent on the side to be dropped, that is, on the side of the mixture (A) at the beginning of the dropwise addition, the carboxylic acid dichloride will be dispersed in a large amount of the alkaline aqueous solution, resulting in an increase in deactivation. Carboxylic acid dichloride more than the considered necessity is required. From the above, it is preferable that both the mixture (A) and the solution (B) contain an organic solvent.

In the present invention, interfacial polymerization is carried out by successively adding solution (B) into mixture (A) in a reactor to produce polyester. Alternatively, the solution (B-1) and the solution (B-2) are successively added simultaneously to the mixture (A) in the reactor to carry out interfacial polymerization to produce the polyester.
When the solution (B) is added sequentially, it is possible to complete the addition of the carboxylic acid dichloride and the terminal terminator at the same time without requiring a high degree of control. On the other hand, the method of sequentially adding the solution (B-1) and the solution (B-2) at the same time requires a high degree of control because the addition of both ends almost simultaneously. Therefore, the former method of sequentially adding the solution (B) is preferred.

In order to sequentially add the solution (B) into the mixture (A) in the reactor, there are a method of continuous addition and a method of intermittent addition. Continuous addition is preferred because the concentration can be kept more constant. For example, a liquid delivery device such as a gear pump that can quantitatively deliver the solution (B) may be used.
The amount of solution (B) fed varies depending on the scale of the production apparatus, but is preferably 10 g/min to 4000 kg/min, more preferably 20 g/min to 2000 kg/min, and particularly preferably 20 g/min to 200 kg/min. is.
The feeding rate of the solution (B) is preferably 1 to 30% by mass/minute, more preferably 5 to 20% by mass/minute of the total amount of the solution (B).
The time for feeding the solution (B), that is, the time for sequential addition, is preferably 5 minutes or more, more preferably 5 minutes or more and 60 minutes or less, and particularly preferably 5 minutes or more and 20 minutes or less.

The sequential addition is usually carried out with stirring at a temperature of 40° C. or lower, preferably 25° C. or lower.

As the reactor used in the present invention, for example, a tank reactor equipped with a stirrer can be used. Examples of the stirrer include a one-way stirrer and a reciprocating rotary stirrer, and it is preferable to use a reciprocating rotary stirrer.

The polystyrene equivalent weight average molecular weight (Mw) of the polyester obtained by the production method of the present invention is preferably 20,000 or more and less than 150,000, more preferably 50,000 or more and 150,000 or less, and particularly preferably 100,000 or more and 150,000 or more. less than 10,000. Further, the polystyrene equivalent number average molecular weight (Mn) is preferably 40,000 or more and less than 80,000, more preferably 10,000 or more and 30,000 or less.
The molecular weight distribution (Mw/Mn) of the polyester obtained by the production method of the present invention is preferably 1.5-15, more preferably 2-10.
When the polystyrene equivalent weight average molecular weight (Mw) is 20,000 or more and less than 150,000, for example, the mechanical strength as a coating material can be kept high, and the processability when processing as a coating material is excellent.
The above Mw and Mn are measured, for example, by gel permeation chromatography (hereinafter abbreviated as GPC).

The amount of terminal chlorine (terminal CL) in the polyester obtained by the production method of the present invention is preferably 5 ppm or less, more preferably 2 ppm or less, and particularly preferably 1 ppm or less. Metal corrosion can be prevented when the amount of terminal chlorine (terminal CL), that is, the amount of chlorine remaining as acid chloride at the polymer terminal is 5 ppm or less. In the present invention, the amount of terminal chlorine (terminal CL) can be measured by the method described in Examples below.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples.

1) polystyrene equivalent weight average molecular weight (Mw) and number average molecular weight (Mn)
Measured using GPC.
Apparatus: Alliance HPLC system manufactured by Waters Inc. Column: Two Shodex805L columns manufactured by Showa Denko K.K. Sample solution: 0.25 w/v% chloroform solution sample Eluent: 1 ml/min chloroform eluent Detection: UV detector at 254 nm Amount of chlorine (terminal CL) The obtained polyester was dissolved in a dichloromethane solvent at a concentration of 0.05 to 5 g/L, 4-(nitrobenzyl)pyridine was added to a concentration of 0.8 g/L, colored. The absorbance of the resulting colored solution was measured at 440 nm, converted to acid chloride concentration using the factor obtained from the absorbance of 0.2 to 20 mol/L phenyl chloroformate standard solution, and further converted to chlorine concentration. bottom.

<Example 1>
In a tank-type reaction vessel equipped with a reciprocating rotary agitator Agitator (registered trademark of Shimazaki Seisakusho Co., Ltd.) as an agitator and a triangular blade, 150 ml of dichloromethane was added as an organic solvent, and 2,2-bis(4- Hydroxy-3-methylphenyl)propane (hereinafter abbreviated as "BPC") 60 g (0.234 mol), a polymerization catalyst, tri-n-butylbenzylammonium chloride (hereinafter abbreviated as "TBBAC"), and all dihydric phenols 0.9 mol % (0.64 g) and 860 ml of a 3 w/w % sodium hydroxide aqueous solution were added and dissolved (preparation of mixture (A)).
Separately from this, 0.7 g (0.0047 mol) of p-tert-butylphenol (hereinafter abbreviated as "PTBP") as a terminal terminator and a mixture of terephthalic acid dichloride/isophthalic acid dichloride=1/1 as a carboxylic acid dichloride were added. 48.5 g (0.239 mol) of (hereinafter abbreviated as "MPC") was dissolved in 350 ml of organic solvent dichloromethane (preparation of solution (B)), and a reaction vessel was stirred. The total amount was added sequentially by continuous addition over 5 minutes. Stirring was then continued for 55 minutes, and the polymerization was completed in 60 minutes total.
After stopping the polymerization, the polymerization solution is separated into an aqueous phase and an organic phase, the organic phase is neutralized with phosphoric acid, the pH of the washing solution becomes neutral, and the conductivity of the aqueous phase becomes 10 μS/cm or less. After repeated washing with water until the polymer solution was washed with water, the resulting polymer solution was dropped into hot water maintained at 60°C, and after dropping, the temperature was raised to 100°C, and the solvent was removed by evaporation to obtain a white granular solid. The obtained solid was filtered and dried at 120° C. for 24 hours to obtain a dried polymer solid. Table 1 shows the results.

<Example 2>
A polymer was obtained in the same manner as in Example 1, except that sequential addition by continuous addition was carried out over 10 minutes, and then stirring was continued for 50 minutes. Table 1 shows the results.

<Example 3>
A polymer was obtained in the same manner as in Example 1, except that sequential addition by continuous addition was carried out over 20 minutes, and then stirring was continued for 40 minutes. Table 1 shows the results.

<Comparative Example 1>
In Example 1, the same operation as in Example 1 was performed except that PTBP, which is a terminal terminator, was not mixed with MPC, which is a carboxylic acid dichloride, and PTBP was initially added to the reaction vessel at the same time as 150 ml of dichloromethane. A polymer was obtained. The polymer had a considerably higher viscosity than the examples. In addition, the terminal of the molecule had a large amount of chlorine content as compared with the examples. Table 1 shows the results.

<Comparative Example 2>
In Example 2, the same operation as in Example 2 was performed except that PTBP, which is a terminal terminator, was not mixed with MPC, which is a carboxylic acid dichloride, and PTBP was initially added to the reaction vessel at the same time as 150 ml of dichloromethane. A polymer was obtained. The polymer had extremely high viscosity compared to the examples. In addition, the terminal of the molecule had a large amount of terminal chlorine (terminal CL) compared to the examples. Table 1 shows the results.

<Comparative Example 3>
In Example 1, instead of adding the entire amount of the solution dissolved in dichloromethane to the reaction vessel sequentially over 5 minutes, the entire amount of the solution was added to the reaction vessel at once in a short period of time (30 seconds) (not sequential addition). Except for this, the same operation as in Example 1 was performed to obtain a polymer. Table 1 shows the results.

Comparative Example 3 corresponds to the invention described in Patent Document 2 in the above [Background Art], but the polyester obtained in Examples 1 to 3 has more terminal chlorine (terminal CL) even lower amounts. Moreover, in Examples 1 to 3, unlike in Comparative Example 3, since the entire amount is not reacted in a short period of time, there is no need to introduce cooling equipment, etc., without accompanying rapid heat generation.
According to the present invention, it is possible to stably control the molecular weight without causing a runaway reaction in the interfacial polyester polymerization by a simpler method than the conventional production method, and to obtain a high-quality polyester with a low chlorine content. can. Especially in a batch type reaction, it is suitable for production of a wide variety of products in small quantities, and its industrial utility value is extremely high.

Claims (6)

A method for producing a polyester by an interfacial polymerization reaction using a dihydric phenol and a carboxylic acid dichloride as raw materials,
A method for producing a polyester, wherein the solution (B) containing the carboxylic acid dichloride and the terminal terminator is sequentially added to the mixture (A) containing the dihydric phenol and the catalyst. The method for producing polyester according to claim 1, wherein the mixture (A) further contains an organic solvent, an alkali metal compound and water. The method for producing a polyester according to claim 1 or 2, wherein the solution (B) further contains an organic solvent. The method for producing a polyester according to any one of claims 1 to 3, wherein the sequential addition is continuous addition. The method for producing a polyester according to any one of claims 1 to 4, wherein the sequential addition time is 5 minutes or longer. The method for producing a polyester according to any one of claims 1 to 5, wherein the method for producing the polyester is a batch type.