JP2012211290A - Method for producing polysulfone with reduced halogen content - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polysulfone with a reduced halogen content, and hardly increasing melt viscosity during melt processing.SOLUTION: The polysulfone is produced by heating a mixture containing a halogen-terminated polysulfone, a basic compound and a solvent to a predetermined temperature, mixing the heated mixture with a metal compound that generates water at the predetermined temperature, and thereafter mixing the resultant mixture with an alkylating agent and/or aralkylating agent. As the basic compound, an alkali metal salt of carbonic acid is used preferably. As the solvent, an aprotic solvent is used preferably. As the metal compound generating water, a metal hydroxide is used preferably.

Description

  In the present invention, from a polysulfone having a halogen atom at the terminal (hereinafter sometimes referred to as “halogen-terminated polysulfone”) to a polysulfone having a hydroxyl group and / or a salt thereof at the terminal (hereinafter referred to as “hydroxy-terminated polysulfone”). And a process for producing polysulfone having a reduced halogen content.

  Since polysulfone is excellent in heat resistance and chemical resistance, application to various applications including materials for electric and electronic parts is being studied. Polysulfone is usually produced by polycondensation of a dihalogenosulfone compound and a dihydroxy compound using a basic compound in a solvent. At that time, the dihalogenosulfone compound is used in excess of the dihydroxy compound. The halogen-terminated polysulfone can be obtained, and the hydroxy-terminated polysulfone can be obtained by using the dihydroxy compound in excess of the dihalogenosulfone compound.

  Hydroxy-terminated polysulfone has been studied preferably as a paint, epoxy curing agent or alloying agent by taking advantage of its hydroxyl-terminated reactivity, but due to its reactivity, its viscosity tends to increase in the molten state, and it is an injection molding material. And is not suitable as a melt-processed material such as an extrusion molding material. Thus, halogen-terminated sulfones are preferably studied as melt-processed materials, but depending on the production conditions, some hydroxy ends may be included, and the problem of an increase in melt viscosity may still occur. Further, in recent years, social demands for reducing environmental burdens are increasing, and in the field of plastics, halogen reduction is an issue, so that there may be a problem in restricting use of halogen-terminated sulfones. Here, the former problem of increase in melt viscosity can be solved by alkylating the hydroxy terminal with an alkylating agent (see, for example, Patent Documents 1 and 2), but the latter problem of use restriction still remains in such technology. .

JP-A-53-12991 JP-A-53-16098

  Accordingly, an object of the present invention is to provide a method capable of producing a polysulfone having a low halogen content, in which the melt viscosity hardly increases during melt processing.

  In order to achieve the above object, the present invention comprises heating a mixture containing a polysulfone having a halogen atom at a terminal, a basic compound, and a solvent to a predetermined temperature and mixing with a metal compound that generates water at the predetermined temperature. And a method for producing a polysulfone having a reduced halogen content, characterized by mixing with an alkylating agent and / or an aralkylating agent.

  According to the present invention, it is possible to produce a polysulfone having a low halogen content, in which the melt viscosity hardly increases during melt processing.

Polysulfone typically has a divalent aromatic group (residue obtained by removing two hydrogen atoms bonded to the aromatic ring from an aromatic compound), a sulfonyl group (—SO ₂ —), an oxygen atom, Is a resin having a repeating unit containing From the viewpoint of heat resistance and chemical resistance, the polysulfone preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as “repeating unit (1)”). The repeating unit represented by (2) (hereinafter sometimes referred to as “repeating unit (2)”) and the repeating unit represented by the following formula (3) (hereinafter referred to as “repeating unit (3)”) And other repeating units may be included.

(1) -Ph ¹ -SO ₂ -Ph ² -O-

(Ph ¹ and Ph ² each independently represent a phenylene group. The hydrogen atoms in the phenylene group may each independently be substituted with an alkyl group, an aryl group, or a halogen atom.)

(2) -Ph ³ -R-Ph ⁴ -O-

(Ph ³ and Ph ⁴ each independently represent a phenylene group. The hydrogen atoms in the phenylene group may each independently be substituted with an alkyl group, an aryl group or a halogen atom. R represents an alkylidene. Represents a group, oxygen atom or sulfur atom.)

(3)-(Ph ⁵ ) _n -O-

(Ph ⁵ represents a phenylene group. Each hydrogen atom in the phenylene group may be independently substituted with an alkyl group, an aryl group or a halogen atom. N represents an integer of 1 to 3. When n is 2 or more, a plurality of Ph ⁵ may be the same or different from each other.)

The phenylene group represented by any of Ph ^{1 to} Ph ⁵ may be a p-phenylene group, an m-phenylene group, or an o-phenylene group. -A phenylene group is preferred. Examples of the alkyl group which may be substituted for the hydrogen atom in the phenylene group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t- A butyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group, and n-decyl group are mentioned, The carbon number is 1-10 normally. Examples of the aryl group which may substitute a hydrogen atom in the phenylene group include a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 1-naphthyl group and 2-naphthyl group. The carbon number is usually 6-20. When the hydrogen atom in the phenylene group is substituted with these groups, the number is usually 2 or less and preferably 1 or less for each phenylene group.

  As an example of the alkylidene group which is R, a methylene group, an ethylidene group, an isopropylidene group, and 1-butylidene group are mentioned, The carbon number is 1-5 normally.

  The polysulfone preferably has the repeating unit (1) of 50 mol% or more, more preferably 80 mol% or more, based on the total of all repeating units, and substantially only the repeating unit (1) as the repeating unit. It is further preferable to have In addition, polysulfone may have 2 or more types of repeating units (1)-(3) each independently.

  Polysulfone can be produced by polycondensation of a dihalogenosulfone compound and a dihydroxy compound corresponding to the repeating unit constituting the polysulfone. For example, a resin having a repeating unit (1) uses a compound represented by the following formula (4) as a dihalogenosulfone compound (hereinafter sometimes referred to as “compound (4)”), and a dihydroxy compound represented by the following formula: It can be produced by using the compound represented by (5) (hereinafter sometimes referred to as “compound (5)”). The resin having the repeating unit (1) and the repeating unit (2) uses the compound (4) as the dihalogenosulfone compound and the compound represented by the following formula (6) as the dihydroxy compound (hereinafter referred to as “compound ( 6) ”may be used to produce the product. In addition, the resin having the repeating unit (1) and the repeating unit (3) uses the compound (4) as the dihalogenosulfone compound and the compound represented by the following formula (7) as the dihydroxy compound (hereinafter referred to as “compound ( 7) "may be used.

^{(4) X 1 -Ph 1 -SO} 2 -Ph 2 -X 2

(X ¹ and X ² each independently represent a halogen atom. Ph ¹ and Ph ² are as defined above.)

(5) HO—Ph ¹ —SO ₂ —Ph ² —OH

(Ph ¹ and Ph ² are as defined above.)

^{(6) HO-Ph 3 -R} -Ph 4 -OH

(Ph ³ , Ph ⁴ and R are as defined above.)

(7) HO— (Ph ⁵ ) _n —OH

(Ph ⁵ and n are as defined above.)

  The polycondensation is preferably performed in a solvent using a basic compound. As the basic compound, an alkali metal carbonate is preferably used. The alkali metal salt of carbonic acid may be an alkali carbonate that is a normal salt, an alkali bicarbonate (an alkali hydrogen carbonate) that is an acidic salt, or a mixture of both. Are preferably sodium carbonate and potassium carbonate, and sodium bicarbonate and potassium bicarbonate are preferably used as the alkali bicarbonate. As the solvent, an aprotic solvent is preferably used, among which dimethyl sulfoxide, 1-methyl-2-pyrrolidone, sulfolane (1,1-dioxothyrane), 1,3-dimethyl-2-imidazolidinone, , 3-diethyl-2-imidazolidinone, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, diphenyl sulfone, N, N-dimethylacetamide and the like are preferably used.

  In the present invention, halogen-terminated polysulfone is used as a raw material, which is first hydrolyzed to convert the terminal halogen atom into a hydroxyl group and / or a salt thereof (hereinafter sometimes referred to as “hydroxyl group”). By doing so, a hydroxy-terminated polysulfone is obtained. Subsequently, the hydroxy-terminated polysulfone is alkylated and / or aralkylated, and the hydroxyl group at the terminal is converted into an alkoxyl group and / or an aralkyloxyl group, whereby a polysulfone having an alkoxyl group and / or an aralkyloxyl group at the terminal ( Hereinafter, it may be referred to as “alkoxy-terminated polysulfone”).

  The halogen-terminated polysulfone can be obtained by using a dihalogenosulfone compound in excess of the dihydroxy compound in the polycondensation. The halogen content of the halogen-terminated polysulfone is preferably 1500 mass ppm or more, more preferably 2000 mass ppm or more.

  The halogen-terminated polysulfone preferably has a reduced viscosity of 0.2 to 0.9 dl / g, more preferably 0.3 to 0.8 dl / g, still more preferably 0.35 to 0.76 dl / g, and particularly preferably. Is 0.4 to 0.6 dl / g. The reduced viscosity is a measure of the degree of polymerization. The higher the reduced viscosity of the halogen-terminated polysulfone, the higher the reduced viscosity of the resulting hydroxy-terminated polysulfone, and hence the alkoxy-terminated polysulfone, that is, the higher the degree of polymerization, the higher the heat resistance and strength. Although it is excellent in rigidity, if it is too high, the melting temperature and melt viscosity are likely to be high, the temperature required for the molding is likely to be high, and the solubility in a solvent is likely to be low.

  In the polycondensation, if no side reaction occurs, the closer the molar ratio of the dihalogenosulfone compound and the dihydroxy compound is to 1: 1, the greater the amount of alkali metal carbonate used, the higher the polycondensation temperature. In addition, the longer the polycondensation time, the higher the degree of polymerization of the resulting polysulfone and the higher the reduced viscosity. In practice, however, the substitution reaction of a halogeno group to a hydroxyl group or the like by a by-product alkali hydroxide or the like A side reaction such as depolymerization occurs, and this side reaction tends to lower the degree of polymerization of the resulting polysulfone and reduce the reduced viscosity. Therefore, considering the degree of this side reaction, a polysulfone having a desired reduced viscosity can be obtained. The molar ratio of the dihalogenosulfone compound to the dihydroxy compound, the amount of alkali metal carbonate used, the polycondensation temperature and the polycondensation time were adjusted so that It is preferable to.

  In the present invention, the hydrolysis of the halogen-terminated polysulfone is carried out by heating a mixture containing the halogen-terminated polysulfone, the basic compound, and the solvent to a predetermined temperature and mixing with the compound that generates water at the predetermined temperature. As a result, rapid hydrolysis at a high temperature becomes possible, a halogen content is reduced, and a polysulfone having a high hydroxy terminal ratio can be produced in a short time.

  Examples of the basic compound include lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and other alkali metal salts of carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide. Alkali metal hydroxides such as rubidium hydroxide and cesium hydroxide, alkali metal salts of acetic acid such as sodium acetate and potassium acetate, alkaline earths of carbonic acid such as calcium carbonate, magnesium hydrogen carbonate, calcium hydrogen carbonate and barium hydrogen carbonate Metal salt, hydroxide of alkaline earth metal such as magnesium hydroxide, hydroxide of quaternary ammonium such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, tertiary amine such as trimethylamine and triethylamine, dimethylamine, Diethyl Secondary amines, such as Min, methylamine, primary amines ethylamine, and include ammonia, may be used two or more thereof. Among these, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide are preferable from the viewpoint of easy handling, and sodium carbonate and potassium carbonate are more preferable.

  The amount of the basic compound used is usually 0.001 to 1 mol times, preferably 0.005 to 0.5 mol times, more preferably 0.005 to 0.1 mol times, and still more preferably relative to the halogen-terminated polysulfone. Is 0.01 to 0.06 mole times. If the amount of the basic compound used is too large, the basic compound cannot be completely dissolved and the reaction becomes non-uniform, the basic compound remains in the polysulfone, or the polysulfone is easily colored. If the amount of basic compound used is too large, hydrolysis will not proceed easily.

  As the solvent, an aprotic solvent is preferably used, among which dimethyl sulfoxide, 1-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, sulfolane (1,1-dioxothyrane), 1 Polar solvents such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N-methyl-2-piperidone, dimethylsulfone, diethylsulfone, diisopropylsulfone, diphenylsulfone are preferably used. Two or more of them may be used. Of these, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone and diphenylsulfone are preferable.

  The amount of solvent used is based on halogen-terminated polysulfone. Usually, it is 1-20 mass times, Preferably it is 1-10 mass times, More preferably, it is 2-5 mass times. If the amount of the solvent used is too small, all of the polysulfone will not dissolve, or even if it is dissolved, the viscosity will be too high and operations such as stirring will be difficult. If the amount of the solvent used is too large, the reaction rate tends to be slow, and the yield during recovery tends to decrease.

Examples of metal compounds that generate water include hydroxides (M ^I OH, M ^II (OH) ₂ , M ^III (OH) _3, etc.), and oxide hydrates (M ^I ₂ O · H ₂ O). , M ^II O.H ₂ O, M ^III ₂ O ₃ .3H ₂ O, etc.), hydroxide hydrates, oxyhydroxide hydrates, and various metal salts including crystal water, Two or more of these may be used. Among them, aluminum hydroxide (crystalline alumina hydrate) is preferable, and examples thereof include gibbsite (Al ₂ O ₃ .H ₂ O (shown by Al (OH) ₃ ), bayerite (a), bayerite. (B), norstrandite, diaspore (Al ₂ O ₃ .H ₂ O (indicative formula AlO (OH))), boehmite, todite (5Al ₂ O ₃ .H ₂ O (indicative formula Al ₅ O ₇ ( OH))), pseudoboehmite (Al ₂ O ₃ .nH ₂ O (shown by the formula AlO (OH) .nH ₂ O)), and aluminogel (Al ₂ O _3. (H ₂ O) n).

  The metal compound that generates water is preferably one that generates water at a temperature of 350 ° C. or lower. If the temperature at which water is generated is too high, the solvent that can raise the temperature to that temperature is limited, and at such a high temperature, polysulfone tends to decompose and color easily.

  The amount of the metal compound used to generate water is preferably 0.01 to 10 mol times, more preferably 0.1 to 10 mol times, and more preferably 0.1 to 10 mol times with respect to the halogen-terminated polysulfone. Preferably it is 0.1-6 mol times. If the amount of the metal compound that generates water is too large, the molecular weight of the resulting hydroxy-terminated polysulfone will decrease, or the amount of hydroxide residue will increase, making it difficult to recover and wash the polysulfone. When the amount of the metal compound that generates water is too small, the reaction does not proceed easily and the hydroxy terminal is difficult to be introduced.

  The reaction temperature, that is, the heating temperature of the mixture, needs to be higher than the temperature at which the metal compound that generates water to be used generates water. Conversely, the metal compound that generates water has a temperature lower than the heating temperature of the mixture. It is necessary to use one that generates water. The heating temperature of the mixture is preferably 100 to 350 ° C, more preferably 150 to 300 ° C, and further preferably 200 to 300 ° C. When the heating temperature of the mixture is too high, the solvent that can be used is limited, and polysulfone is easily decomposed and colored. When the heating temperature of the mixture is too low, the reaction does not proceed easily and the hydroxy terminal is difficult to be introduced.

  The reaction time is preferably 1 minute to 1 hour, more preferably 5 minutes to 1 hour, even more preferably 5 to 30 minutes, and particularly preferably 5 to 10 minutes. However, it is possible to obtain a polysulfone having a reduced halogen content and a high hydroxy terminal ratio, and suppressing the decomposition reaction and coloring of the polysulfone.

  Since the reaction system contains a basic compound and is at a high temperature, the hydroxy-terminated polysulfone is easily oxidized. Therefore, the reaction atmosphere preferably does not contain oxygen, and the reaction is performed in an inert gas atmosphere such as nitrogen. Is preferred.

  The resulting reaction mixture is then mixed with an alkylating agent and / or aralkylating agent to alkylate and / or aralkylate the hydroxy-terminated polysulfone in the reaction mixture to obtain an alkoxy-terminated polysulfone.

  As the alkylating agent, alkyl halides such as alkyl chloride and alkyl chloride such as t-butyl chloride are preferably used, and two or more of them may be used. As the aralkylating agent, aralkyl halides such as aralkyl chloride such as benzyl chloride are preferably used, and two or more of them may be used.

  The alkylation and / or aralkylation is preferably carried out by blowing a gaseous alkylating agent and / or aralkylating agent into the reaction mixture containing the hydroxy-terminated polysulfone.

  The alkoxy-terminated polysulfone is recovered from the reaction mixture by separating the basic compound and its residue and the residue of the metal compound that generates water from the reaction mixture by filtration and centrifugation, and the resulting alkoxy-terminated polysulfone solution is obtained. Mixing with an alkoxy-terminated polysulfone poor solvent to precipitate the alkoxy-terminated polysulfone, or mixing the reaction mixture with an alkoxy-terminated polysulfone poor solvent to precipitate the alkoxy-terminated polysulfone. Also good. Examples of the poor solvent for the alkoxy-terminated polysulfone include alcohols such as methanol, ethanol, isopropanol and butanol, nitriles such as acetonitrile, and water, and two or more of them may be used. The poor solvent may contain a good solvent for the alkoxy-terminated polysulfone such as a reaction solvent as long as the alkoxy-terminated polysulfone can be precipitated. An additive such as an agent may be added.

  It is preferable that the alkoxy-terminated polysulfone after precipitation recovery is dried after washing with the poor solvent.

  The alkoxy-terminated polysulfone thus obtained has a halogen content of preferably 900 mass ppm or less, more preferably 500 mass ppm or less. Moreover, the reduced viscosity becomes like this. Preferably it is 0.2-0.7 dl / g, More preferably, it is 0.4-0.7 dl / g.

  According to the present invention, it is possible to obtain a polysulfone having a halogen content of 900 ppm by mass or less, a reduced viscosity of 0.4 to 0.7 dl / g, a low halogen content, and a high degree of polymerization.

(Measurement of reduced viscosity of polysulfone)
About 1 g of polysulfone was dissolved in N, N-dimethylformamide to make its volume 1 dl, and the viscosity (η) of this solution was measured at 25 ° C. using an Ostwald type viscosity tube. Further, the viscosity (η ₀ ) of N, N-dimethylformamide as a solvent was measured at 25 ° C. using an Ostwald type viscosity tube. From the viscosity (η) of the solution and the viscosity (η ₀ ) of the solvent, the specific viscosity ((η−η ₀ ) / η ₀ ) is obtained, and this specific viscosity is calculated as the concentration of the solution (about 1 g / dl). ) To determine the reduced viscosity (dl / g) of polysulfone.

[Measurement of chlorine content in polysulfone]
Polysulfone was weighed into a quartz boat, burned with oxygen, and the generated gas was absorbed in alkaline water and quantified by ion chromatography.

[Measurement of melt viscosity of polysulfone]
Using a flow tester (“CFT-500D type” manufactured by Shimadzu Corporation), about 2 g of polysulfone was filled in a cylinder equipped with a die having a nozzle having an inner diameter of 1 mm and a length of 10 mm, and heated to 400 ° C. After 5 minutes, the melt viscosity of polysulfone after 30 minutes was measured.

Reference Example 1 (Preparation of chloro-terminated polysulfone (1))
In a polymerization tank having a capacity of 2000 ml equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a condenser with a receiver at the tip, 614.2 g (2.14 mol) of 4,4′-dichlorodiphenylsulfone, 4,4 After putting 525.0 g (2.10 mol) of '-dihydroxydiphenylsulfone and 784.0 g of diphenylsulfone as a polymerization solvent and raising the temperature to 180 ° C. while circulating nitrogen gas in the system, 300.8 g of anhydrous potassium carbonate The mixture was gradually heated to 290 ° C. and reacted at 290 ° C. for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the solidified reaction mass was finely pulverized and then washed with warm water to remove potassium chloride. Further, washing with a mixed solvent of acetone and methanol was performed several times to remove diphenylsulfone as a polymerization solvent, and then washing with water, followed by drying at 150 ° C. by heating. The average particle diameter of the obtained powdery polysulfone was 500 μm. Table 1 shows the reduced viscosity, chlorine content and melt viscosity of this polysulfone.

Reference Example 1 (Preparation of chloro-terminated polysulfone (2))
In a polymerization tank having a capacity of 2000 ml equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a condenser with a receiver at the tip, 4,9.3 ′ (2.12 mol) of 4,4′-dichlorodiphenylsulfone, 4,4 After putting 525.0 g (2.10 mol) of '-dihydroxydiphenylsulfone and 784.0 g of diphenylsulfone as a polymerization solvent and raising the temperature to 180 ° C. while circulating nitrogen gas in the system, 300.8 g of anhydrous potassium carbonate Add. The temperature was gradually raised to 290 ° C., and the reaction was carried out at 290 ° C. for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the solidified reaction mass was finely pulverized and then washed with warm water to remove potassium chloride. Further, washing with a mixed solvent of acetone and methanol was performed several times to remove diphenylsulfone as a polymerization solvent, and then washing with water, followed by drying at 150 ° C. by heating. The average particle diameter of the obtained powdery polysulfone was 500 μm. Table 1 shows the reduced viscosity, chlorine content and melt viscosity of this polysulfone.

[Aluminum hydroxide]
As aluminum hydroxide, “CW-375HT” manufactured by Sumitomo Chemical Co., Ltd. was used. This aluminum hydroxide has an endothermic onset of 200 ° C. and an endothermic peak of 300 ° C. by DSC measurement at a temperature rising rate of 10 ° C./min, and the theoretically released water content is 34.6% by mass.

  In a 500 ml SUS separable flask equipped with a stirring blade, a cooling tube (Dimroth (water cooling)), a nitrogen introduction tube, and a thermometer, 166.6 g of chloro-terminated polysulfone (1) and 230.0 g of diphenylsulfone as a solvent were added. Then, the mixture was heated to 285 ° C. using an oil bath with stirring under a nitrogen gas flow, and melted and dissolved. The polysulfone concentration is 42% by mass. After dissolution and the internal temperature were stabilized, 1.98 g of finely powdered anhydrous potassium carbonate was added and dispersed, and then 5.0 g of aluminum hydroxide was added and stirred for 15 minutes.

  After completion of the stirring, methyl chloride gas was blown for 30 minutes, and the reaction solution was immediately filtered at 150 ° C. while hot to separate the aluminum hydroxide residue and potassium carbonate residue. Was added dropwise to precipitate polysulfone. The filter paper was washed with 100 ml of N-methylpyrrolidone three times, and the washing was dropped into the hydrochloric acid methanol as it was. The precipitated polysulfone was washed twice with 1000 ml of water and once with 1000 ml of methanol, and then recovered and vacuum dried at 150 ° C. The resulting polysulfone was in the form of a white powder. Table 1 shows the yield (recovered polysulfone mass / raw material polysulfone mass), reduced viscosity, halogen content, and melt viscosity of this polysulfone.

Example 2
The same procedure as in Example 1 was carried out except that chloro-terminated polysulfone (2) was used as the raw material polysulfone and the amount of diphenylsulfone used as the solvent was 330.0 g. The results are shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was performed except that methyl chloride gas was not blown. The results are shown in Table 1.

Comparative Example 2
The same procedure as in Example 2 was performed except that methyl chloride gas was not blown. The results are shown in Table 1.

Claims (13)

  A mixture containing a polysulfone having a halogen atom at the end, a basic compound, and a solvent is heated to a predetermined temperature and mixed with a metal compound that generates water at the predetermined temperature, and then an alkylating agent and / or an aralkylating agent, A method for producing a polysulfone having a reduced halogen content, characterized by mixing.   The manufacturing method according to claim 1, wherein the predetermined temperature is 100 to 350 ° C. The production method according to claim 1 or 2, wherein the polysulfone having a halogen atom at a terminal is a polysulfone having a repeating unit represented by the following formula (1).
Equation ^{(1): - Ph 1 -SO} 2 -Ph 2 -O-
(Ph ¹ and Ph ² each independently represent a phenylene group. The hydrogen atoms in the phenylene group may each independently be substituted with an alkyl group, an aryl group, or a halogen atom.)   The manufacturing method according to claim 1, wherein the basic compound is an alkali metal salt of carbonic acid.   The said solvent is an aprotic solvent, The manufacturing method in any one of Claims 1-4.   The manufacturing method according to claim 1, wherein the metal compound is a metal hydroxide.   The amount of the metal compound used is represented by the amount of water generated by the metal compound, and is 0.01 to 10 moles times the polysulfone having a halogen atom at the terminal. The manufacturing method as described.   The method according to claim 1, wherein the alkylating agent and / or aralkylating agent is an alkyl halide and / or a halogenated aralkyl.   The production method according to any one of claims 1 to 7, wherein a halogen content in the polysulfone having a halogen atom at a terminal is 1500 mass ppm or more.   The production method according to claim 1, wherein the halogen content in the polysulfone having a reduced halogen content is 900 mass ppm or less.   The production method according to any one of claims 1 to 9, wherein the reduced viscosity of the polysulfone having a halogen atom at a terminal is 0.2 to 0.9 dl / g.   The manufacturing method according to any one of claims 1 to 10, wherein the reduced viscosity of the polysulfone having a reduced halogen content is 0.2 to 0.7 dl / g.   Polysulfone having a halogen content of 900 mass ppm or less and a reduced viscosity of 0.4 to 0.7 dl / g.