JP7825492B2 - Method for producing polyarylene ether ketone resin - Google Patents

Description

The present invention relates to a method for producing polyarylene ether ketone resin.

Conventionally, methods described in Patent Documents 1 to 4 have been known as methods for producing polyarylene ether ketone resins.

U.S. Pat. No. 4,839,459 Japanese Patent Application Laid-Open No. 2020-530051 Japanese Patent Application Laid-Open No. 2020-502337 Japanese Patent Application Laid-Open No. 2020-143262

Patent Document 1 describes a production method using an oligomer. However, in the method of Patent Document 1, raw materials are mixed simultaneously, and further, when trifluoroacetic anhydride is used, it can be a poor solvent for the monomer. Therefore, when terephthalic acid or the oligomer shown in the following (1-1) is used, the monomer does not dissolve completely, and it has been found that it is difficult to extend the molecular weight.
Patent Document 2 describes a production method using an oligomer. However, because a compound containing aluminum or chlorine is used as a catalyst, elements such as aluminum and chlorine remain in the resulting resin, resulting in poor thermal stability during molding and the generation of outgassing during molding.
Patent Document 3 describes a method for producing polyether ketone ketone. However, the method of Patent Document 3 involves residual fluorine element derived from the monomer and residual high-boiling point solvent, which causes problems with thermal stability and outgassing during molding processing.
Patent Document 4 describes a method for producing polyarylene ether ketone using an aromatic dicarboxylic acid and a compound having an aromatic ether skeleton or an aromatic thioether skeleton. However, the method described in Patent Document 4 has a low rate of arylene groups sandwiched between a ketone and an ether in a repeating unit contained in the main chain, in which the bonding position between the ketone and the ether is para-positioned, resulting in poor thermal stability during molding processing.
As described above, the polyarylene ether ketone resin obtained by the conventional method does not have sufficient thermal stability, and when heated during molding processing, gas is generated due to decomposition of residues and structural defects (e.g., ortho structures) contained in the resin, resulting in a large amount of outgassing during molding processing.

Therefore, an object of the present invention is to provide a method for efficiently producing polyarylene ether ketone resins that have excellent thermal stability and few residues or structural defects that cause outgassing.

That is, the present invention is as follows.
[1]
Step (I) of preparing a mixed solution of a dicarboxylic acid, an acid having a pKa of 0 or less, and an anhydride of the acid having a pKa of 0 or less;
a step (II) of pre-dissolving an oligomer represented by the following formula (1-1) or (1-2) in an acid having a pKa of 0 or less to prepare a pre-dissolved oligomer; and a step (III) of adding the mixed solution prepared in the step (I) to the pre-dissolved oligomer prepared in the step (II) to prepare a polymerization raw material liquid.
A method for producing a polyarylene ether ketone resin, comprising:
[2]
[1] The method for producing a polyarylene ether ketone resin according to [1], wherein in the step (II), the temperature for pre-dissolving the oligomer is 20°C or higher and 150°C or lower.
[3]
The method for producing a polyarylene ether ketone resin according to [1] or [2], wherein in the step (II), the oligomer is pre-dissolved for a time period of 1 minute or more and 6 hours or less.
[4]
The method for producing a polyarylene ether ketone resin according to any one of [1] to [3], wherein the residual mass ratio of chlorine element relative to 100 mass% of the obtained polyarylene ether ketone resin is 500 ppm or less.
[5]
The method for producing a polyarylene ether ketone resin according to any one of [1] to [4], wherein the polymerization raw material liquid obtained in the step (III) is polymerized under conditions of a temperature of 0°C or higher and 162°C or lower.
[6]
The method for producing a polyarylene ether ketone resin according to any one of [1] to [5], wherein the acid having a pKa of 0 or less used in the step (I) and the acid having a pKa of 0 or less used in the step (II) are both fluorine atom-containing sulfonic acids represented by the following general formula (2-1):
(In the formula, R ¹ and R ² may be the same or different and each represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms.)
[7]
The method for producing a polyarylene ether ketone resin according to any one of [1] to [6], wherein the anhydride of an acid having a pKa of 0 or less is a fluorine atom-containing sulfonic acid anhydride represented by the following general formula (3-1) and/or a fluorine atom-containing acetic acid anhydride represented by the following general formula (4-1):
(In the formula, R ¹ and R ² may be the same or different and each represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms.)
[8]
[8] The method for producing a polyarylene ether ketone resin according to any one of [1] to [7], wherein the dicarboxylic acid is terephthalic acid and/or isophthalic acid.

The polyarylene ketone resin manufacturing method of the present invention, having the above-described configuration, can efficiently produce polyarylene ether ketone resin with excellent thermal stability and little residue or structural defects that cause outgassing.

The following provides a detailed description of an embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to the following description and can be modified in various ways within the scope of its gist.

[Method of producing polyarylene ether ketone resin]
The method for producing a polyarylene ether ketone resin of the present embodiment is characterized by including: a step (I) of preparing a mixed solution of a dicarboxylic acid, an acid having a pKa of 0 or less, and an anhydride of the acid having a pKa of 0 or less; a step (II) of pre-dissolving an oligomer represented by the following formula (1-1) or (1-2) in an acid having a pKa of 0 or less to prepare a pre-dissolved oligomer; and a step (III) of adding the mixed solution prepared in the step (I) to the pre-dissolved oligomer prepared in the step (II) to prepare a polymerization raw material liquid.

(Step (I))
The step (I) is a step of mixing the dicarboxylic acid, the acid having a pKa of 0 or less, and the anhydride of the acid having a pKa of 0 or less to prepare a mixed solution.
The order in which the dicarboxylic acid, the acid having a pKa of 0 or less, and the anhydride of the acid having a pKa of 0 or less are added is not particularly limited, and they may be mixed simultaneously or in any order.

-dicarboxylic acid-
Examples of the dicarboxylic acid include aromatic dicarboxylic acids, and since a resin having even more excellent thermal stability can be obtained, terephthalic acid, isophthalic acid, 4,4'-dicarboxydiphenyl ether, 2,6-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid are preferred, and terephthalic acid and/or isophthalic acid are more preferred.
The dicarboxylic acids may be used alone or in combination of two or more.

- Acid with pKa of 0 or less -
The acid having a pKa of 0 or less used in step (I) and the acid having a pKa of 0 or less used in step (II) are preferably both compounds described below.
The acid having a pKa of 0 or less used in step (I) and the acid having a pKa of 0 or less used in step (II) may be the same or different. In particular, from the viewpoint of reaction efficiency, it is preferable that they are the same.
The acid having a pKa of 0 or less is a fluorine atom-containing sulfonic acid represented by the following formula (2-1):
(wherein R ¹ and R ² may be the same or different and represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms which may be substituted with a fluorine atom), is preferred, and from the viewpoint of obtaining a resin having a high molecular weight and excellent thermal stability, trifluoromethanesulfonic acid and nonafluorobutanesulfonic acid are more preferred, and trifluoromethanesulfonic acid is even more preferred.
The acids having a pKa of 0 or less may be used alone or in combination of two or more.

-Anhydride of an acid with a pKa of 0 or less-
The acid anhydride having a pKa of 0 or less is preferably a fluorine atom-containing sulfonic acid anhydride represented by the following general formula (3-1) and/or a fluorine atom-containing acetic acid anhydride represented by the following general formula (4-1).
(In the formula, R ¹ and R ² may be the same or different and each represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms.)

Examples of the fluorine atom-containing sulfonic acid anhydride include trifluoromethanesulfonic acid anhydride and chlorodifluoromethanesulfonic acid anhydride.
The acid anhydride having a pKa of 0 or less is preferably trifluoroacetic anhydride, from the viewpoint of obtaining a resin having a high molecular weight and excellent thermal stability.
The anhydrides of acids having a pKa of 0 or less may be used singly or in combination of two or more.

The acid with a pKa of 0 or less in the anhydride of the acid with a pKa of 0 or less is preferably the same as the acid with a pKa of 0 or less used in step (I), and preferably the same as the acid with a pKa of 0 or less used in steps (I) and (II). Furthermore, if the pKa of the acid with a pKa of 0 or less in the anhydride of the acid with a pKa of 0 or less is too low, the water present in the reaction system will react before the nucleophile reacts. Therefore, the pKa of the acid is preferably -8 to 0, more preferably -7 to 0, and even more preferably -6 to 0.

In step (I), the molar ratio of the acid having a pKa of 0 or less to be added relative to 1 mole of the dicarboxylic acid is preferably 2 to 8 moles, more preferably 2.5 to 7.5 moles, and even more preferably 3 to 10 moles, because a small amount of the acid prevents the dicarboxylic acid from dissolving and reduces the reactivity, whereas a large amount of the acid reduces the concentration and reduces the reactivity.
In step (I), the molar ratio of the anhydride of the acid having a pKa of 0 or less to be added relative to 1 mole of the dicarboxylic acid is preferably 2 to 5 moles, more preferably 2.1 to 4.5 moles, and even more preferably 2.1 to 4 moles, from the viewpoint of obtaining a resin having better thermal stability and containing less residue.

It is preferable to add the dicarboxylic acid, the acid having a pKa of 0 or less, and the anhydride of the acid having a pKa of 0 or less, and then stir the mixture.
From the viewpoint of obtaining a resin having a high molecular weight and excellent thermal stability, the stirring temperature is preferably (boiling point -40°C) to (boiling point +10°C) of the anhydride of the acid having a pKa of 0 or less under the pressure of the system, more preferably (boiling point -35°C) to (boiling point +5°C). It is preferable that the temperature during stirring is constant.
The pressure range is preferably 0.08 to 1.0 MPa, and more preferably 0.09 to 0.9 MPa.
The stirring is preferably carried out under a nitrogen atmosphere at normal pressure.
The stirring time is preferably 1 minute to 12 hours, more preferably 3 minutes to 8 hours, since sufficient time is required for dissolution.

After preparation, the above mixture may be used immediately in step (III), or may be stored before being used in step (III).

The mass proportion of dicarboxylic acid in the above-mentioned mixed solution (100% by mass) is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass, because if the amount is too small, the dicarboxylic acid will not dissolve and the reactivity will decrease, while if the amount is too large, the concentration will be low and the reactivity will decrease.

The mass proportion of the acid with a pKa of 0 or less in 100% by mass of the mixed solution is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and even more preferably 20 to 60% by mass, because if the amount is too small, the dicarboxylic acid will not dissolve and the reactivity will decrease, while if the amount is too large, the concentration will be low and the reactivity will decrease.

The mass proportion of the anhydride of the acid having a pKa of 0 or less in 100 mass% of the mixed solution is preferably 20 to 70 mass%, more preferably 25 to 65 mass%, and even more preferably 25 to 60 mass%, from the viewpoint that a small amount results in an insufficient reaction, whereas an excessively large amount results in poor solubility of the dicarboxylic acid.
The total mass of the dicarboxylic acid, the acid having a pKa of 0 or less, and the anhydride of the acid having a pKa of 0 or less relative to 100% by mass of the mixed solution may be 80% by mass or more, 90% by mass or more, or 100% by mass, or may be less than 100% by mass.

In step (I), compounds other than the dicarboxylic acid, the acid having a pKa of 0 or less, and the anhydride of the acid having a pKa of 0 or less may be added. Examples of the other compounds include dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dichlorobenzene, nitromethane, nitrobenzene, trichloroacetic acid, trichloroacetic anhydride, chlorodifluoroacetic acid, chlorodifluoroacetic anhydride, acetic acid, acetic anhydride, benzoic acid, and benzoic anhydride.
The mass ratio of the other compounds relative to 100% by mass of the mixed liquid is preferably 20% by mass or less, and more preferably 10% by mass or less.

(Step (II))
The step (II) is a step of preparing a pre-dissolved oligomer by pre-dissolving an oligomer represented by the following formula (1-1) or (1-2) in an acid having a pKa of 0 or less.

The acid having a pKa of 0 or less used in step (II) includes the acids described above having a pKa of 0 or less.

In step (II), the molar ratio of the acid having a pKa of 0 or less added per mole of the oligomer is preferably 1 to 30 moles, more preferably 2 to 25 moles, and even more preferably 3 to 20 moles, because if the amount is small, the oligomer will not dissolve and the reactivity will decrease, while if the amount is large, the concentration will be low and the reactivity will decrease.

The above oligomer can be obtained, for example, by copolymerizing diphenyl ether and dicarboxylic acid. Copolymerization conditions include, for example, a temperature of 0 to 70°C and a time of 30 minutes to 10 hours. The ratio of addition during copolymerization is, for example, 0.1 to 0.5 moles of dicarboxylic acid per mole of diphenyl ether.

In the step (II), it is preferable to add the oligomer and the acid having a pKa of 0 or less, and then pre-dissolve them while stirring.
The above-mentioned pre-dissolution is preferably carried out under a nitrogen atmosphere at normal pressure.

In the step (II), the temperature at which the oligomer is pre-dissolved is the minimum temperature necessary for dissolution, and is therefore preferably (boiling point - 160°C) to (boiling point + 20°C) under the pressure of the system, more preferably (boiling point - 150°C) to (boiling point + 10°C).
The pressure range is preferably 0.08 MPa to 1.0 MPa, and more preferably 0.09 MPa to 0.9 MPa.

In step (II) above, the time for pre-dissolving the oligomer is preferably 1 minute to 6 hours, more preferably 10 minutes to 5 hours, and even more preferably 30 minutes to 4 hours, from the viewpoint that the oligomer needs to be sufficiently dissolved.

The above-mentioned pre-dissolved oligomer may be used in step (III) immediately after preparation, or may be stored before use in step (III).

The mass proportion of the oligomer in 100% by mass of the pre-dissolved oligomer is preferably 1 to 51% by mass, more preferably 10 to 51% by mass, and even more preferably 20 to 51% by mass, because if the amount is too large, the oligomer will not dissolve and the reactivity will decrease, and if the amount is too small, the concentration will be low and the reactivity will decrease.

The mass proportion of the acid having a pKa of 0 or less relative to 100 mass% of the pre-dissolved oligomer is preferably 49 to 99 mass%, more preferably 49 to 90 mass%, and even more preferably 49 to 80 mass%, because a large amount results in a low concentration and low reactivity, while a small amount does not sufficiently dissolve the oligomer and results in poor reactivity.
The total mass of the oligomer and the acid having a pKa of 0 or less relative to 100% by mass of the pre-dissolved oligomer may be 80% by mass or more, 90% by mass or more, or 100% by mass, or may be less than 100% by mass.

In step (II), a compound other than the oligomer and the acid having a pKa of not more than 0 may be added. Examples of the other compound include dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dichlorobenzene, nitromethane, nitrobenzene, trichloroacetic acid, trichloroacetic anhydride, chlorodifluoroacetic acid, chlorodifluoroacetic anhydride, acetic acid, acetic anhydride, terephthalic acid, isophthalic acid, benzoic acid, benzoic anhydride, p-toluenesulfonic acid, p-toluenesulfonic anhydride, methanesulfonic acid, and methanesulfonic anhydride.
The mass ratio of the other compounds to 100% by mass of the pre-dissolved oligomer is preferably 20% by mass or less, and more preferably 10% by mass or less.

(Step (III))
The step (III) is a step of preparing a polymerization raw material liquid by adding the mixed solution prepared in the step (I) to the pre-dissolved oligomer prepared in the step (II). Adding the pre-dissolved oligomer prepared in the step (II) to the mixed solution prepared in the step (I) in the step (III) is not preferred because the pre-dissolved oligomer prepared in the step (II) has a very high viscosity, making it difficult to match the monomer ratio.
The present inventors have found that conventional methods of simultaneously mixing raw material monomers result in poor efficiency because some of the raw materials do not dissolve completely, preventing the reaction from proceeding. Therefore, they have discovered that by preparing a reaction intermediate by mixing a dicarboxylic acid, an acid with a pKa of 0 or less, and an anhydride of an acid with a pKa of 0 or less, and then adding this reaction intermediate to a pre-dissolved solution of an oligomer, the reaction can be initiated in a homogeneous system and the reaction proceeds efficiently. Furthermore, they have found that the resin obtained by the method of the present invention has very little residual metal or halogen elements and a high para content, and therefore has excellent thermal stability during molding and can suppress outgassing due to heating during molding. They have also found that resins with excellent thermal stability can be obtained, with little by-products such as diphenyl sulfone and carboxylic acid, and little weight loss upon heating.

In step (III), if the mass ratio of the pre-dissolved oligomer added to 100 parts by mass of the mixed solution is too low, the concentration will be low and reactivity will be poor. If the mass ratio is too high, the oligomer will not completely dissolve and reactivity will be poor. Therefore, the mass ratio is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, and even more preferably 1 to 6 parts by mass.

In step (III), other compounds may be added to the mixed solution and the pre-dissolved oligomer, such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dichlorobenzene, nitromethane, nitrobenzene, trichloroacetic acid, trichloroacetic anhydride, chlorodifluoroacetic acid, chlorodifluoroacetic anhydride, acetic acid, acetic anhydride, terephthalic acid, isophthalic acid, benzoic acid, benzoic anhydride, p-toluenesulfonic acid, p-toluenesulfonic anhydride, methanesulfonic acid, and methanesulfonic anhydride.
The mass ratio of the other compounds relative to 100% by mass of the polymerization raw material liquid is preferably 20% by mass or less, and more preferably 10% by mass or less.

The polymerization raw material liquid is preferably subjected to a polymerization reaction continuously after preparation.
The polymerization temperature is preferably from (boiling point -160°C) to (boiling point +20°C) of an acid having a pKa of 0 or less under the pressure of the system, more preferably from (boiling point -155°C) to (boiling point +10°C), and even more preferably from (boiling point -150°C) to (boiling point +5°C).
The pressure range is preferably 0.08 MPa to 1.0 MPa, and more preferably 0.09 MPa to 0.9 MPa.
In order to more efficiently proceed with the polymerization reaction, the temperature of the polymerization is preferably higher than the temperature at which the polymerization raw material liquid was prepared, more preferably 10°C or more higher than the temperature at which the polymerization raw material liquid was prepared, and even more preferably 20°C or more higher than the temperature at which the polymerization raw material liquid was prepared.
The temperature during preparation of the polymerization raw material liquid may be, for example, 0°C or higher and lower than 50°C, and may be 10°C or higher and lower than 40°C.

The polymerization time is preferably 1 to 24 hours, more preferably 2 to 18 hours, and even more preferably 3 to 12 hours.

The above polymerization is preferably carried out with stirring.

After the polymerization, the mixture may be cooled and then poured into a solvent that will precipitate the polyarylene ether ketone resin.
The temperature after cooling under atmospheric pressure may be −90° C. to 40° C., and may be −80° C. to 30° C., or may be room temperature. Examples of the solvent for precipitating the polyarylene ether ketone resin include water (e.g., distilled water), ethanol, and methanol.

The precipitated polyarylene ether ketone resin may be subjected to filtration, washing, purification, and the like.
The washing is preferably carried out after filtration. Examples of the washing include washing with an alkaline solution (preferably an aqueous sodium hydroxide solution, more preferably a 0.5 to 2N aqueous sodium hydroxide solution), ethanol, distilled water, an organic solvent (preferably orthodichlorobenzene), etc. Among these, from the viewpoint of efficiently reducing the amounts of remaining Al, fluorine, and chlorine, washing at least multiple times (for example, twice) with the alkaline aqueous solution is preferred, and washing with the alkaline aqueous solution multiple times and at least one time with distilled water is more preferred.

[Polyarylene ether ketone resin]
Examples of the polyarylene ether ketone resin of this embodiment include resins produced by the above-described method for producing a polyarylene ether ketone resin of this embodiment.

The above polyarylene ether ketone resin is preferably a polyether ketone ketone resin.

The polyarylene ether ketone resin may be a resin containing a repeating unit (5-1) represented by the following formula (5-1) and/or a repeating unit (5-2) represented by the following formula (5-2), or may be a resin consisting only of the repeating unit (5-1) and/or the repeating unit (5-2).

The polyarylene ether ketone resin may contain repeating units other than the repeating units (5-1) and (5-2).
The proportion by total mass of the repeating unit (5-1) and the repeating unit (5-2) relative to 100% by mass of the polyarylene ether ketone resin is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

From the viewpoint of achieving even better thermal stability, the polyarylene ether ketone resin preferably satisfies the following (A) and (B):
(A) Terminal carboxylic acid units are present in an amount of 0 to 0.5 mol% relative to all terminal groups
(B) The mass ratio of the high-boiling point solvent to 100 mass% of the polyarylene ether ketone resin is 0.1 mass% or less

From the viewpoint of achieving even better thermal stability, the number of moles of terminal carboxylic acid units relative to 100 mol % of all terminal groups of the polyarylene ether ketone resin is preferably 0 to 0.5 mol %, more preferably 0 to 0.3 mol %, and even more preferably 0 to 0.1 mol %.
The number of moles of the terminal carboxylic acid unit can be measured by the method described in the Examples below.

The mass ratio of the high-boiling point solvent relative to 100 mass% of the polyarylene ether ketone resin of the present embodiment is preferably 1 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.3 mass% or less, still more preferably 0.1 mass% or less, still more preferably 0.05 mass% or less, and particularly preferably 0.03 mass% or less.
The high boiling point solvent may be a solvent having a boiling point of 170° C. or higher (preferably 170 to 380° C.) at normal pressure.
The mass proportion of the high-boiling point solvent can be measured by the method described in the examples below.

From the viewpoint of achieving even better thermal stability, the polyarylene ether ketone resin is preferably a resin that satisfies the following (A') and (B):
(A') The mass ratio of the low molecular weight carboxylic acid to 100 mass% of the polyarylene ether ketone resin is 0 to 0.5 mass%
(B) The mass ratio of the high-boiling point solvent to 100 mass% of the polyarylene ether ketone resin is 0.1 mass% or less

The mass proportion of the low molecular weight carboxylic acid relative to 100 mass% of the polyarylene ether ketone resin is preferably 0 to 2 mass%, more preferably 0.5 mass% or less, and even more preferably 0.3 mass% or less.
The low-molecular-weight carboxylic acid may be a carboxylic acid having a weight-average molecular weight of not more than 400 as measured by GPC. The low-molecular-weight carboxylic acid may be a monocarboxylic acid.
The mass proportion of the low-molecular-weight carboxylic acid can be measured by the method described in the Examples below.

From the viewpoint of achieving even better thermal stability, the polyarylene ether ketone resin is preferably a resin that satisfies the following (C) to (G).
(C) The resin contains a repeating unit containing a structure derived from a dicarboxylic acid and a structure derived from a diphenyl ether, and the para ratio, which is the ratio of the total number of phenylenes in which the carbonyl group is bonded to the para position of the phenylene, as viewed from the oxygen atom derived from the ether, to the total number of phenylenes bonded to the carbonyl group in the structure derived from the dicarboxylic acid and the ether in the structure derived from the diphenyl ether contained in the resin, is 99% or more. (D) The number average molecular weight Mn calculated by GPC is 8,000 or more and less than 30,000. (E) The residual amount of Al element is 500 ppm or less. (F) The residual amount of F element is 500 ppm or less. (G) The residual amount of Cl element is 500 ppm or less.

The para ratio of the polyarylene ether ketone resin is preferably 99% or more, more preferably 99.1% or more, and even more preferably 99.2% or more, from the viewpoints of achieving better thermal stability during molding and making it less likely that side reactions will occur during molding.
The para ratio can be measured by the method described in the Examples below.
The para ratio refers to the ratio of the number of phenylenes in a resin having repeating units containing a structure derived from a dicarboxylic acid and a structure derived from diphenyl ether, in which the carbonyl group is bonded to the para position of the phenylene relative to the oxygen atom derived from the ether, relative to the total number of phenylenes bonded to the carbonyl group in the structure derived from the dicarboxylic acid and the ether in the structure derived from the diphenyl ether. For example, the following formula is a para isomer because the carbonyl group in the structure derived from the dicarboxylic acid is bonded to the para position of the phenylene carbon atom to which the oxygen atom of the ether in the structure derived from the diphenyl ether is bonded. A high para ratio means that the proportion of phenylenes bonded to the ortho and meta positions is low. A high para ratio reduces the number of bent structures in the resin, further improving thermal stability.

The polyarylene ether ketone resin preferably has a number-average molecular weight (Mn) calculated by GPC of 8,000 to 30,000, more preferably 8,000 or more but less than 30,000, even more preferably 8,000 to 28,000, and particularly preferably 8,000 to 25,000. If the number-average molecular weight exceeds the upper limit, the cleaning efficiency deteriorates and fluorine elements tend to remain in the resin. Furthermore, the small amount of residual fluorine elements results in a low rate of thermal weight loss.
The molecular weight distribution Mw/Mn of the PAEK resin of the present embodiment, which is expressed as the ratio of the weight average molecular weight Mw to the number average molecular weight Mn, is 4.2 or less, preferably 1.5 to 4.1, more preferably 1.6 to 4.0, even more preferably 1.7 to 3.9, and particularly preferably 1.8 to 3.8.
When the molecular weight distribution is within the above range, a resin having excellent thermal stability can be obtained.
The number average molecular weight and molecular weight distribution can be measured by the method described in the Examples below.

The residual mass ratio of aluminum element relative to 100 mass% of the polyarylene ether ketone resin is preferably 500 ppm or less, more preferably 100 ppm or less, even more preferably 80 ppm or less, still more preferably 60 ppm or less, and most preferably 20 ppm or less, from the viewpoint of further suppressing side reactions during molding and further improving thermal stability during molding. Furthermore, in consideration of the possibility of impurities being mixed in due to contamination, etc., it may be 1 ppm or more.
The remaining mass ratio of aluminum element can be measured by the method described in the examples below.

The residual mass ratio of elemental fluorine relative to 100 mass% of the polyarylene ether ketone resin is preferably 1000 ppm or less, more preferably 500 ppm or less, and even more preferably 200 ppm or less, from the viewpoint of further suppressing outgassing during molding. In addition, taking into consideration the possibility of impurities being mixed in due to contamination, it may be 1 ppm or more.
The remaining mass proportion of elemental fluorine can be measured by the method described in the Examples below.

The residual mass ratio of chlorine element relative to 100 mass% of the polyarylene ether ketone resin is preferably 500 ppm or less, more preferably 350 ppm or less, even more preferably 200 ppm or less, even more preferably 100 ppm or less, even more preferably 75 ppm or less, even more preferably 50 ppm or less, even more preferably 20 ppm or less, and particularly preferably 10 ppm or less, from the viewpoint of further suppressing outgassing during molding. Furthermore, in consideration of the possibility of impurities being mixed in due to contamination, etc., it may be 1 ppm or more.
The remaining mass proportion of chlorine element can be measured by the method described in the Examples below.

The Td1 thermal weight loss rate of the polyarylene ether ketone resin as measured by TGA is preferably 490°C or higher, more preferably 495°C or higher, and even more preferably 500°C or higher, from the viewpoint of suppressing outgassing during molding processing.
The Td1 thermal weight loss rate can be measured by the method described in the Examples below.

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

(evaluation)
The resins obtained in the examples and comparative examples described below were evaluated by the following methods.

[Measurement of number average molecular weight Mn and molecular weight distribution Mw/Mn]
The PAEK resins obtained in the examples and comparative examples were measured for number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw/Mn) using a Tosoh Corporation GPC apparatus (HPLC8320) with HLC-83220GPC EcoSEC System Control Version 1.14 as the apparatus control software and the RI detector included as standard equipment. The eluent was hexafluoroisopropanol in which 0.4% by mass of sodium trifluoroacetate was dissolved. A Shodex KF-606M column was used. Polymethyl methacrylate (PMMA) was used as the standard substance. The measurement results were analyzed using HLC-83220GPC EcoSEC Data Analysis Version 1.15. A baseline was drawn from the rise to fall of the chromatographic peak, and the number average molecular weight Mn, weight average molecular weight Mw, and molecular weight distribution Mw/Mn were calculated from the obtained peaks by conversion using a PMMA calibration curve (Agilent, EasiVial) of the standard substance.

[Elemental analysis]
Approximately 0.1 g of the PAEK resin sample obtained in the examples and comparative examples was precisely weighed into a tetrafluorometaxil (TFM) decomposition vessel, and sulfuric acid and nitric acid were added. The decomposition solution was then subjected to pressure acid decomposition using a microwave decomposition device. The resulting decomposition solution was adjusted to a constant volume of 50 mL and subjected to ICP-MS measurement. Quantitative analysis was performed using an Agilent Technologies (Agilent 7900) instrument.

[Thermogravimetric reduction rate]
The PAEK resins obtained in the examples and comparative examples were heated from room temperature to 560°C at a rate of 20°C/min in a nitrogen stream of 20 mL/min using TGA (TGA apparatus (TG-DTA2500 Regulus) manufactured by NETZSCH), and the temperature at which the thermal weight loss rate (%) reached 1% was determined (hereinafter referred to as Td1) and used as an index of the amount of outgassing. It is determined that the higher the Td1, the smaller the amount of outgassing.

[Quantitative Determination of Para Ratio in PAEK Resin by NMR]
The PAEK resins obtained in the Examples and Comparative Examples described below were dissolved in HFIP-d ₂ /CDCl 3 (9:1) and measured using a JEOL NMR apparatus (ECZ-500) under the conditions of ¹ H observation nucleus, a waiting time of 5 seconds, a measurement temperature of 25°C, and 256 accumulations. The molar ratio of the para-isomer derived units and the ortho-isomer derived units was calculated from the integral values of the characteristic signals of these units, thereby calculating the para ratio. The chemical shifts were measured using the chemical shift of HFIP-d ₂ (4.4 ppm) as the standard, and the signals derived from the para-isomer and ortho-isomer were confirmed by two-dimensional NMR, and the respective quantifications were calculated based on the signals observed at 7.2-7.3 ppm and 8.5-8.6 ppm.

[Quantitative Determination of Terminal Carboxylic Acid Units in PAEK Resins by NMR]
The PAEK resins obtained in the examples and comparative examples described below were dissolved in HFIP-d ₂ /CDCl 3 (9:1) and measured using a JEOL NMR apparatus (ECZ-500) under the conditions of ¹ H observation nucleus, a waiting time of 5 seconds, a measurement temperature of 25°C, and 256 accumulations. The molar ratio of terminal carboxylic acid-derived units and terminal ether-derived units was calculated from the integral values of their respective characteristic signals, thereby calculating the terminal carboxylic acid ratio. The chemical shifts were measured using the chemical shift of HFIP-d ₂ (4.4 ppm) as the standard, and the signals derived from terminal carboxylic acid and terminal ether were confirmed by two-dimensional NMR, and their quantification was calculated based on the signals observed at 8.20-8.29 ppm and 8.47-8.49 ppm, respectively.

[Quantitative determination of diphenyl sulfone by GC]
All analyses were performed using GC/MS Agilent 7890 and Agilent 5975.
Column: HP-5MS (L 30 m, I.D 0.250 mm, Film 0.25 μm)
Carrier Helium Detector MSD
Ionization method EI
Oven temperature: 40°C (5 min hold) → 20°C/min → 320°C (10 min hold)
Inlet temperature 250℃
Transfer temperature: 320°C
Mass range m/z 10-800
Injection mode: Splitless Injection volume: 1 ul
Measurement mode SIM

[Quantitative determination of low molecular weight carboxylic acids by GC]
All analyses were performed using GC/MS Agilent 7890 and Agilent 5975.
Column: HP-5MS (L 30 m, ID 0.250 mm, Film 0.25 μm)
Carrier Helium Detector MSD
Ionization method EI
Oven temperature: 40°C (5 min hold) → 20°C/min → 320°C (10 min hold)
Inlet temperature 250℃
Transfer temperature: 320°C
Mass range m/z 10-800
Injection mode: Splitless Injection volume: 1 ul
Measurement mode SIM
Pretreatment Esterification

The oligomer shown in (1-1) above was synthesized as follows: Unless otherwise specified in the examples, polymerization will be carried out using the oligomer synthesized by this method.
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 350 g of trifluoromethanesulfonic acid, 125 g of terephthalic acid, 350 g of trifluoroacetic anhydride, and 375 g of diphenyl ether, and the mixture was stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure. After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and a polymer was precipitated and filtered. The filtered polymer was then washed twice each with a 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The product was then dried under vacuum at 150°C for 8 hours.
Similarly, an oligomer represented by the formula (1-1) was synthesized by the method described in U.S. Pat. No. 4,816,556. Elemental analysis using the method described above confirmed that 1,000 ppm of aluminum remained. Hereinafter, the oligomer synthesized by this method will be referred to as an aluminum-residual oligomer.

Example 1
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE (an oligomer represented by formula (1-1)). The mixture was stirred at room temperature (25°C) for 2 hours under a nitrogen atmosphere at normal pressure (first reaction). A separate separable flask was charged with 48 g of terephthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride. The mixture was stirred at 40°C for 2 hours under a nitrogen atmosphere at normal pressure (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,200, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 2
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 38 g of terephthalic acid, 9.6 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,500, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 3
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 26 g of terephthalic acid, 19 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 9,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 4
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8700, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 5
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). Another separable flask was charged with 9.6 g of terephthalic acid, 38 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. The molecular weight and molecular weight distribution were measured using GPC. The molecular weight was measured and found to be Mn 9100, confirming that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 6
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 3 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 15,000, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 7
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 6 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 23,000, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

(Example 8)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 12 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 29,500, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 9
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 48 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,800, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 10
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 2 g of benzoic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8100, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 11
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 2 g of benzoic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed three times each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8100, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 12
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed once with aqueous HCl solution, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 13
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed twice with aqueous HCl solution, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,200, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 14
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed three times with aqueous HCl solution, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8100, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 15
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE (35 g of the 140 g was used as aluminum residual oligomer) and stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. Thereafter, the polymer was dried under vacuum at 150° C. for 8 hours. When the molecular weight was measured using GPC, Mn was found to be 8,300, confirming that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 1.

Example 16
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE (70 g of the 140 g was aluminum residual oligomer) and stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. Thereafter, the polymer was dried under vacuum at 150° C. for 8 hours. When the molecular weight was measured using GPC, Mn was found to be 8000, confirming that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 17)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE (using aluminum residual oligomer) and stirred at 25°C for 2 hours under a nitrogen atmosphere at normal pressure (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C for 2 hours under a nitrogen atmosphere at normal pressure (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,200, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 18)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed once with a 1N aqueous sodium hydroxide solution, then twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,500, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

Example 19
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,400, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 20)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed once with distilled water and once with ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,800, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 21)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 138 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8100, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

Example 22
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 137 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,200, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 23)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 136 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 24)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed once with orthodichlorobenzene, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,200, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

Example 25
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice with orthodichlorobenzene, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 26)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was washed three times with orthodichlorobenzene, then twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,400, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 27)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice with 1N aqueous sodium hydroxide solution, twice with distilled water, and once with ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 28)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice with 1N aqueous sodium hydroxide solution, followed by washing once with distilled water and once with ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8,300, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Example 29)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice with 1N aqueous sodium hydroxide solution and once with distilled water. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 8000, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 2.

(Comparative Example 1)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 404 g of trifluoromethanesulfonic acid, 140 g of EKKE, 19 g of terephthalic acid, 29 g of isophthalic acid, and 151 g of trifluoroacetic anhydride, and the mixture was stirred at 40 ° C. for 12 hours under a nitrogen atmosphere at atmospheric pressure. After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was further washed twice with a 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150 ° C. for 8 hours. The molecular weight was measured using GPC, and it was confirmed that Mn was 2000, confirming that a PAEK resin (PEKK polymer) had been obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

Comparative Example 2: Example Using Aluminum Chloride A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 11 g of terephthalic acid dichloride, 17 g of isophthalic acid chloride, 71 g of EKKE, and 163 g of o-dichlorobenzene. 102 g of anhydrous aluminum trichloride was added while maintaining the temperature at 5°C or below under a nitrogen atmosphere at atmospheric pressure, and the mixture was stirred at 0°C for 30 minutes. Subsequently, 1,000 g of o-dichlorobenzene was added, and the mixture was stirred at 130°C for 1 hour. After cooling to room temperature, the supernatant was removed by decantation, and the remaining reaction suspension was poured into a vigorously stirred 1N aqueous sodium hydroxide solution to precipitate a polymer, which was then filtered. The filtered polymer was then washed twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, the Mn was found to be 8,000, confirming that a PAEK resin (PEKK polymer) had been obtained.
The resulting PEKK polymer was analyzed as described above, and the results are shown in Table 3.

Comparative Example 3: Simultaneous Monomer Mixing Method: 11 g of terephthalic acid, 17 g of isophthalic acid, 71 g of diphenyl ether, trifluoroacetic anhydride, and trifluoromethanesulfonic acid were charged into a four-neck separable flask equipped with a nitrogen inlet tube, a thermometer, a reflux condenser, and a stirrer. The mixture was stirred at 70°C for 1 hour while maintaining the temperature at 5°C or below under a nitrogen atmosphere at normal pressure. After cooling to room temperature, the supernatant was removed by decantation, and the remaining reaction suspension was poured into a vigorously stirred 1N aqueous sodium hydroxide solution to precipitate a polymer, which was then filtered. The filtered polymer was then washed twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. The molecular weight was measured using GPC, and it was confirmed that Mn was 5100, confirming that a PAEK resin (PEKK polymer) had been obtained.
The resulting PEKK polymer was analyzed as described above, and the results are shown in Table 3.

Comparative Example 4 Monomer Preactivation Method 35 g of terephthalic acid, 15 g of isophthalic acid, 170 g of trifluoromethanesulfonic acid, and 158 g of trifluoroacetic anhydride were charged into a four-neck separable flask equipped with a nitrogen inlet tube, a thermometer, a reflux condenser, and a stirrer, and the mixture was stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). The mixture was cooled to -5°C, and then 51 g of diphenyl ether was added while maintaining the temperature below 5°C. The mixture was then heated to 70°C and stirred for 6 hours (second reaction). After cooling to room temperature, the reaction solution was poured into a vigorously stirred 1N aqueous sodium hydroxide solution, and a polymer was precipitated and filtered. The filtered polymer was further washed twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. The molecular weight was measured using GPC, revealing that the Mn was 8,300, confirming that a PAEK resin (PEKK polymer) had been obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

(Comparative Example 5)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 48 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). A second reaction compound was added to the first reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 15 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 31,000, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

(Comparative Example 6)
102 g of diphenyl sulfone, 18.5 g of 1,3-bis(4'-hydroxybenzoyl)benzene, 6.36 g of Na ₂ CO ₃ , and 0.040 g of K ₂ CO ₃ were added to a four-neck reaction flask. The flask was equipped with a stirrer, a N ₂ inlet tube, a Claisen adapter with a thermocouple into the reaction medium, and a Dean-Stark trap with a reflux condenser and a dry ice trap. The flask contents were evacuated under vacuum and then filled with high-purity nitrogen (<10 ppm O 2 ). The reaction mixture was then placed under a constant nitrogen purge (60 mL/min).
The reaction mixture was slowly heated from room temperature to 180° C. At 180° C., 18.9 g of 1,4-bis(4′-fluorobenzoyl)benzene was added to the reaction mixture via a powder dispenser over 30 minutes. At the end of the addition, the reaction mixture was heated to 220° C. at 1° C./min.
At 220° C., a mixture of 13.7 g of 1,4-bis(4′-fluorobenzoyl)benzene, 13.4 g of 1,4-bis(4′-hydroxybenzoyl)benzene, 4.61 g of NaCO and 0.029 g of KCO was slowly added to the reaction mixture over 30 minutes.
At the end of the addition, the reaction mixture was heated to 320°C at 1°C/min. After a 5 minute hold at 320°C, 1.29 g of 1,4-bis(4'-fluorobenzoyl)benzene was added to the reaction mixture while maintaining a nitrogen purge in the flask. After 5 minutes, 0.427 g of lithium chloride was added to the reaction mixture. After 10 minutes, another 0.323 g of 1,4-bis(4'-fluorobenzoyl)benzene was added to the reaction flask and the reaction mixture was held constant temperature for 15 minutes.
The contents of the reactor were then poured into a stainless steel pan and allowed to cool. The solids were crushed and passed through a 2 mm screen in an attrition mill. The diphenyl sulfone and salts were extracted from the mixture with acetone and water. The powder was then removed from the reactor and dried at 160°C under vacuum for 12 hours. The molecular weight was measured using GPC to find that the Mn was 8800, confirming that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

(Comparative Example 7)
The polymer purified in Comparative Example 2 was further washed twice with distilled water and twice with ethanol, and then dried under vacuum at 150° C. for 8 hours before each analysis.

(Comparative Example 8)
The polymer purified in Comparative Example 2 was washed four times with distilled water and four times with ethanol, and then dried under vacuum at 150° C. for eight hours before each analysis.

Comparative Example 9: Example using aluminum chloride (end-capping)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 11 g of terephthalic acid dichloride, 17 g of isophthalic acid chloride, 71 g of EKKE, and 163 g of o-dichlorobenzene. While maintaining the temperature at 5°C or below under a nitrogen atmosphere at atmospheric pressure, 102 g of anhydrous aluminum trichloride was added and the mixture was stirred at 0°C for 30 minutes. Subsequently, 1,000 g of o-dichlorobenzene was added, and the mixture was stirred at 130°C for 1 hour. After cooling to room temperature, the supernatant was removed by decantation, and the remaining reaction suspension was poured into a vigorously stirred 1N aqueous sodium hydroxide solution to precipitate a polymer, which was then filtered. The filtered polymer was further washed twice with distilled water and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. The molecular weight was measured using GPC, revealing that the Mn was 8,000, confirming that a PAEK resin (PEKK polymer) had been obtained.
The resulting PEKK polymer was analyzed as described above, and the results are shown in Table 3.

(Comparative Example 10)
A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 269 g of trifluoromethanesulfonic acid and 140 g of EKKE, and the mixture was stirred at 25°C under a nitrogen atmosphere at normal pressure for 2 hours (first reaction). In a separate separable flask, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged and stirred at 40°C under a nitrogen atmosphere at normal pressure for 2 hours (second reaction). The first reaction compound was added to the second reaction mixture at room temperature. The mixture was then heated to 70°C and stirred for 2 hours (third reaction). After cooling to room temperature, the reaction solution was poured into vigorously stirred distilled water, and the polymer was precipitated and filtered. The filtered polymer was then washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried under vacuum at 150°C for 8 hours. When the molecular weight was measured using GPC, it was found that Mn was 4500, and it was confirmed that a PAEK resin (PEKK polymer) was obtained.
The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

In Table 1, repeating units 5-1 and 5-2 have the following structures.

Claims (8)

Step (I) of preparing a mixed solution of a dicarboxylic acid, an acid having a pKa of 0 or less, and an anhydride of the acid having a pKa of 0 or less;
a step (II) of pre-dissolving an oligomer represented by the following formula (1-1) or (1-2) in an acid having a pKa of 0 or less to prepare a pre-dissolved oligomer; and a step (III) of adding the mixed solution prepared in the step (I) to the pre-dissolved oligomer prepared in the step (II) to prepare a polymerization raw material liquid.
A method for producing a polyarylene ether ketone resin, comprising:
The method for producing a polyarylene ether ketone resin according to claim 1, wherein in step (II), the temperature at which the oligomer is pre-dissolved is 20°C or higher and 150°C or lower. The method for producing a polyarylene ether ketone resin according to claim 1 or 2, wherein in step (II), the oligomer is pre-dissolved for a period of 1 minute or more and 6 hours or less. The method for producing a polyarylene ether ketone resin according to any one of claims 1 to 3, wherein the residual mass ratio of elemental chlorine per 100 mass% of the obtained polyarylene ether ketone resin is 500 ppm or less. The method for producing a polyarylene ether ketone resin according to any one of claims 1 to 4, wherein the polymerization raw material liquid obtained in step (III) is polymerized at a temperature of 0°C or higher and 162°C or lower. The method for producing a polyarylene ether ketone resin according to any one of claims 1 to 5, wherein the acid having a pKa of 0 or less used in the step (I) and the acid having a pKa of 0 or less used in the step (II) are both fluorine atom-containing sulfonic acids represented by the following general formula (2-1):
(In the formula, R ¹ and R ² may be the same or different and each represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms.) The method for producing a polyarylene ether ketone resin according to any one of claims 1 to 6, wherein the anhydride of an acid having a pKa of 0 or less is a fluorine atom-containing sulfonic acid anhydride represented by the following general formula (3-1) and/or a fluorine atom-containing acetic acid anhydride represented by the following general formula (4-1):
(In the formula, R ¹ and R ² may be the same or different and each represent a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms.)
The method for producing a polyarylene ether ketone resin according to any one of claims 1 to 7, wherein the dicarboxylic acid is terephthalic acid and/or isophthalic acid.