Method for producing polyarylene ether ketone resin

Abstract

To provide a method for efficiently producing a polyarylene ether ketone resin which is excellent in thermal stability and has less residues causing out gas.SOLUTION: A method for producing a polyarylene ether ketone resin includes: a step (I) of preparing a mixed liquid of a dicarboxylic acid, an acid having a pKa of 0 or less and an anhydride of the acid having the pKa of 0 or less; a step (II) of previously dissolving an oligomer represented by formula (1-1) or (1-2) in the acid having the pKa of 0 or less, and preparing a previously dissolved oligomer; and a step (III) of adding the mixed liquid prepared in the step (I) to the previously dissolved oligomer prepared in the step (II), and preparing a polymerization raw material liquid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polyarylene ether ketone resin. [Background technology]

[0002] Conventionally, the methods described in Patent Documents 1 to 4 have been known as methods for producing polyarylene ether ketone resins. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 4,839,459 [Patent Document 2] Japanese Patent Publication No. 2020-530051 [Patent Document 3] Japanese Patent Publication No. 2020-502337 [Patent Document 4] Japanese Patent Publication No. 2020-143262 Summary of the Invention [Problem to be solved by the invention]

[0004] 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, so that 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 in Patent Document 3 involves residual fluorine elements derived from the monomer and residual high-boiling point solvents, 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. Thus, 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.

[0005] Therefore, an object of the present invention is to provide a method for efficiently producing a polyarylene ether ketone resin that has excellent thermal stability and little residue or structural defects that cause outgassing. [Means for solving the problem]

[0006] 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; 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 solution; A method for producing a polyarylene ether ketone resin, comprising: [ka] [ka] [2] 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 the condition 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): [ka] (R in the formula 1 and R 2 may be the same or different and are 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): [ka] (R in the formula 1 and R 2 may be the same or different and are a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms. [ka] [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. [Effects of the Invention]

[0007] The method for producing a polyarylene ketone resin of the present invention has the above-mentioned configuration, and therefore can efficiently produce a polyarylene ether ketone resin that has excellent thermal stability and little residue or structural defects that cause outgassing. DETAILED DESCRIPTION OF THE INVENTION

[0008] Below, we will explain in detail the form for implementing the present invention (hereinafter referred to as the ``present embodiment''), but the present invention is not limited to the following description and can be implemented in various modifications within the scope of its gist.

[0009] [Method of producing polyarylene ether ketone resin] The method for producing a polyarylene ether ketone resin of the present embodiment is characterized by comprising: 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; 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 step (III) of adding the mixed solution prepared in step (I) to the pre-dissolved oligomer prepared in step (II) to prepare a polymerization raw material liquid. [ka] [ka]

[0010] (Process (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.

[0011] -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 singly or in combination of two or more.

[0012] -Acids with pKa below 0- 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. 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): [ka] (R in the formula 1 and R 2may be the same or different and are 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 singly or in combination of two or more kinds.

[0013] -Anhydrides of acids with pKa less than 0- 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). [ka] (R in the formula 1 and R 2 may be the same or different and are a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms. [ka]

[0014] 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.

[0015] The acid having a pKa of 0 or less in the anhydride of an acid having a pKa of 0 or less is preferably the same as the acid having a pKa of 0 or less used in step (I), and is preferably the same as the acid having a pKa of 0 or less used in steps (I) and (II). Furthermore, if the pKa of the acid having a pKa of 0 or less in the anhydride of an acid having a pKa of 0 or less is too low, water present in the reaction system will react before the nucleophile reacts, so the pKa of the acid is preferably -8 or more and 0 or less, more preferably -7 or more and 0 or less, and even more preferably -6 or more and 0 or less.

[0016] In step (I), the molar ratio of the acid having a pKa of 0 or less 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, since a small amount will not dissolve the dicarboxylic acid and reduce the reactivity, while a large amount will dilute the concentration and reduce 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.

[0017] 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 with 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.

[0018] The mixed solution may be used in step (III) immediately after preparation, or may be stored before use in step (III).

[0019] The mass proportion of the dicarboxylic acid in the above-mentioned mixed liquid (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, since if the amount is small, the dicarboxylic acid does not dissolve and the reactivity decreases, and if the amount is large, the concentration becomes low and the reactivity decreases.

[0020] The mass proportion of the acid having a pKa of 0 or less in 100 mass% of the mixed solution is preferably 10 to 70 mass%, more preferably 15 to 65 mass%, and even more preferably 20 to 60 mass%, because if the amount is too small, the dicarboxylic acid does not dissolve and the reactivity decreases, and if the amount is too large, the concentration becomes low and the reactivity decreases.

[0021] 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 if the amount is too small, the reaction will not be sufficient, and if the amount is too large, the solubility of the dicarboxylic acid will be poor. 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.

[0022] In the 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 to 100% by mass of the mixed liquid is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0023] (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. [ka] [ka]

[0024] The acid having a pKa of 0 or less used in step (II) includes the above-mentioned acids having a pKa of 0 or less.

[0025] In step (II), the molar ratio of the acid having a pKa of 0 or less to be added relative to 1 mole of the oligomer is preferably 1 to 30 moles, more preferably 2 to 25 moles, and even more preferably 3 to 20 moles, since a small amount will result in the oligomer not dissolving and the reactivity decreasing, while a large amount will result in a low concentration and a decrease in the reactivity.

[0026] The oligomer can be obtained, for example, by copolymerizing diphenyl ether and dicarboxylic acid. The copolymerization conditions include, for example, a temperature of 0 to 70°C and a time of 30 minutes to 10 hours. The ratio of the dicarboxylic acid added during copolymerization is, for example, 0.1 to 0.5 moles per mole of diphenyl ether.

[0027] In the step (II), it is preferable to add the oligomer and the acid having a pKa of 0 or less, and then dissolve them in advance while stirring. The above-mentioned pre-dissolution is preferably carried out under a nitrogen atmosphere at normal pressure.

[0028] 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.

[0029] In the step (II), 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.

[0030] The pre-dissolved oligomer may be used in step (III) immediately after preparation, or may be stored before use in step (III).

[0031] 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.

[0032] 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 will result in a low concentration and low reactivity, while a small amount will not sufficiently dissolve the oligomer and will result 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.

[0033] 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.

[0034] (Process (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 the oligomer, the reaction can be initiated in a homogeneous system and 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, which results in excellent thermal stability during molding and suppresses 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.

[0035] In step (III), the mass ratio of the pre-dissolved oligomer added to 100 parts by mass of the mixed solution 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, since a small amount results in a low concentration and poor reactivity, whereas a large amount results in the oligomer not being completely dissolved and poor reactivity.

[0036] 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.

[0037] 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 the 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 proceed with the polymerization reaction more efficiently, 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.

[0038] The polymerization time is preferably 1 to 24 hours, more preferably 2 to 18 hours, and even more preferably 3 to 12 hours.

[0039] The polymerization is preferably carried out with stirring.

[0040] 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 may be −90° C. to 40° C. under atmospheric pressure, and may be −80° C. to 30° C. or room temperature. Examples of the solvent for precipitating the polyarylene ether ketone resin include water (e.g., distilled water), ethanol, and methanol.

[0041] 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 residual amounts of 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.

[0042] [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.

[0043] The polyarylene ether ketone resin is preferably a polyether ketone ketone resin.

[0044] 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). [ka] [ka]

[0045] The polyarylene ether ketone resin may contain repeating units other than the repeating units (5-1) and (5-2). The proportion of the 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.

[0046] 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 0 to 0.5 mol% of all terminal groups (B) A mass ratio of a high-boiling point solvent to 100 mass% of the polyarylene ether ketone resin is 0.1 mass% or less

[0047] 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%, from the viewpoint of achieving even better thermal stability. The number of moles of the terminal carboxylic acid unit can be measured by the method described in the Examples below.

[0048] The mass ratio of the high-boiling point solvent relative to 100 mass% of the polyarylene ether ketone resin of this embodiment is preferably 1 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.3 mass% or less, even 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.

[0049] 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) A mass ratio of a high-boiling point solvent to 100 mass% of the polyarylene ether ketone resin is 0.1 mass% or less

[0050] 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 also 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.

[0051] 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) A resin containing a repeating unit containing a structure derived from a dicarboxylic acid and a structure derived from a diphenyl ether, wherein the para ratio, which is the ratio of the total number of phenylenes bonded to carbonyl groups in the structure derived from the dicarboxylic acid and ethers in the structure derived from the diphenyl ether, to the total number of phenylenes having the carbonyl groups bonded to the para positions of the phenylenes relative to the oxygen atom derived from the ether, is 99% or more. (D) GPC-equivalent number average molecular weight Mn is 8,000 or more and less than 30,000 (E) Residual amount of Al element is 500 ppm or less (F) Residual amount of F element is 500 ppm or less (G) Residual amount of Cl element is 500 ppm or less

[0052] 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 reducing the likelihood of side reactions occurring 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. [ka]

[0053] 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 reduces the rate of thermal weight loss. Furthermore, the molecular weight distribution Mw / Mn of the PAEK resin of this 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.

[0054] 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.

[0055] The residual mass ratio of elemental fluorine relative to 100% by 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, in consideration of 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.

[0056] 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.

[0057] 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. The Td1 thermal weight loss rate can be measured by the method described in the Examples below. [Example]

[0058] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0059] (evaluation) The resins obtained in the examples and comparative examples described below were evaluated by the following methods.

[0060] [Measurement of number average molecular weight Mn and molecular weight distribution Mw / Mn] The number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the PAEK resins obtained in the examples and comparative examples were measured using a Tosoh Corporation GPC system (HPLC8320) with the instrument control software HLC-83220GPC EcoSEC System Control Version 1.14 and the instrument's standard RI detector. The eluent was hexafluoroisopropanol containing 0.4% by weight of sodium trifluoroacetate. A Shodex KF-606M column was used. Polymethyl methacrylate (PMMA) was used as the standard material. Analysis of the measurement results was performed using HLC-83220GPC EcoSEC Data Analysis Version 1.15. A baseline was drawn from the rise to fall of the chromatographic peak. The number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) were calculated from the peaks obtained by conversion using the PMMA calibration curve (Agilent, EasiVial) of the standard material.

[0061] [Elemental analysis] Approximately 0.1 g of the PAEK resin samples obtained in the examples and comparative examples were weighed into a tetrafluoromethane (TFM) decomposition vessel, and sulfuric acid and nitric acid were added. The resulting decomposition solution was then subjected to pressure acid decomposition in a microwave decomposition apparatus. The resulting solution was adjusted to a volume of 50 mL and subjected to ICP-MS analysis. Quantitative analysis was performed using an Agilent Technologies (Agilent 7900) instrument.

[0062] [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 using a TGA (TGA apparatus (TG-DTA2500 Regulus) manufactured by NETZSCH) in a nitrogen gas flow of 20 mL / min, 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 lower the amount of outgassing.

[0063] [Quantitative determination of para content in PAEK resin by NMR] The PAEK resins obtained in the examples and comparative examples described below were dissolved in HFIP-d2 / CDCl3 (9:1) and analyzed using a JEOL NMR apparatus (ECZ-500). 1 Measurements were performed under the following conditions: H as the observation nucleus, a waiting time of 5 seconds, a measurement temperature of 25°C, and 256 accumulations. The molar ratio of the para-isomer and the ortho-isomer was calculated from the integrals of the characteristic signals of these units, and the para ratio was calculated. The chemical shifts were measured using the chemical shift of HFIP-d2 (4.4 ppm) as the standard, and the signals derived from the para-isomer and the ortho-isomer were confirmed by two-dimensional NMR. The quantification of each was calculated based on the signals observed at 7.2-7.3 ppm and 8.5-8.6 ppm.

[0064] [Quantitative Analysis 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-d2 / CDCl3 (9:1) and analyzed using a JEOL NMR apparatus (ECZ-500). 1Measurements were performed under the following conditions: H as the observation nucleus, a waiting time of 5 seconds, a measurement temperature of 25°C, and 256 accumulations. The molar ratio of terminal carboxylic acid units and terminal ether units was calculated from the integrals of their respective characteristic signals, and the terminal carboxylic acid ratio was calculated. The chemical shifts were measured using the chemical shift of HFIP-d2 (4.4 ppm) as the standard. The signals derived from terminal carboxylic acids and terminal ethers 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.

[0065] [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 um) Carrier Helium Detector MSD Ionization method EI Oven temperature: 40℃ (5min hold) → 20℃ / min → 320℃ (10min hold) Inlet temperature 250℃ Transfer temperature: 320℃ Mass range m / z 10-800 Injection mode Splitless Injection volume 1ul Measurement mode SIM

[0066] [Quantitative analysis 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, I.D 0.250 mm, Film 0.25 um) Carrier Helium Detector MSD Ionization method EI Oven temperature: 40℃ (5min hold) → 20℃ / min → 320℃ (10min hold) Inlet temperature 250℃ Transfer temperature: 320℃ Mass range m / z 10-800 Injection mode Splitless Injection volume 1ul Measurement mode SIM Pretreatment Esterification

[0067] 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 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 to precipitate a polymer, which was then filtered. The filtered polymer was then washed twice with 1N aqueous sodium hydroxide, 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. Patent 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.

[0068] 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)) and stirred at room temperature (25°C) for 2 hours under a nitrogen atmosphere at atmospheric 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 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 8200, 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.

[0069] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 38 g of terephthalic acid, 9.6 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 confirmed that Mn was 8500, and 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.

[0070] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 26 g of terephthalic acid, 19 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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, Mn was found to be 9300, 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.

[0071] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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, Mn was found to be 8700, 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.

[0072] 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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate 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 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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, and it was confirmed that the molecular weight was Mn of 9100, and 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.

[0073] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 confirmed that Mn was 15,000, and 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.

[0074] 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 atmospheric pressure for 2 hours (first reaction). Separately, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged to a separate separable flask, and the mixture was stirred at 40°C under a nitrogen atmosphere at atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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.

[0075] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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, Mn was found to be 29,500, 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.

[0076] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 48 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 atmospheric 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 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 confirmed that Mn was 8800, and 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.

[0077] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 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, and the mixture was stirred at 40°C under a nitrogen atmosphere at atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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.

[0078] 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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 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, and the mixture was 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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.

[0079] 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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was 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 washed once with aqueous HCl, then twice each with 1N aqueous sodium hydroxide, 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 8300, 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.

[0080] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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, then twice each with 1N aqueous sodium hydroxide, 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 8200, 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.

[0081] 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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was 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 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.

[0082] 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 aluminum residual oligomer) and stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). Separately, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged to a separate separable flask 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 to precipitate a polymer, which was then 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 8300, 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 1.

[0083] 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). Separately, 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride were charged to a separate separable flask 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 to precipitate a polymer, which was then filtered. The filtered polymer was washed twice each with 1N aqueous sodium hydroxide solution, distilled water, and ethanol. The polymer was then dried for 8 hours under vacuum at 150° C. When the molecular weight was measured using GPC, it was found that Mn was 8000, 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 2.

[0084] 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 (aluminum residual oligomer) and stirred at 25°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 8200, 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.

[0085] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 1N aqueous sodium hydroxide solution, then twice each 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 confirmed that Mn was 8500, and 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.

[0086] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was washed twice with distilled water and twice 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 confirmed that Mn was 8400, and 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.

[0087] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 confirmed that Mn was 8800, and 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.

[0088] 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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was 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 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.

[0089] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 8200, 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.

[0090] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 8300, 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.

[0091] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 8200, 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.

[0092] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 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 8300, 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.

[0093] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 confirmed that Mn was 8400, and 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.

[0094] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 1N aqueous sodium hydroxide, 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 8300, 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.

[0095] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 1N aqueous sodium hydroxide solution, then once each 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 8300, 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.

[0096] 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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 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 atmospheric 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 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 confirmed that Mn was 8000, and 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.

[0097] (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. 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 to precipitate the polymer, which was then filtered. The filtered polymer was washed twice with 1N aqueous sodium hydroxide, 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 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.

[0098] 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. Under atmospheric pressure and a nitrogen atmosphere, 102 g of anhydrous aluminum trichloride was added and the mixture was stirred at 0°C for 30 minutes. 1,000 g of o-dichlorobenzene was then 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 the 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, revealing that the Mn was 8,000, confirming the formation of a PAEK resin (PEKK polymer). The resulting PEKK polymer was analyzed as described above, and the results are shown in Table 3.

[0099] (Comparative Example 3) Monomer simultaneous mixing method A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 11 g of terephthalic acid, 17 g of isophthalic acid, 71 g of diphenyl ether, trifluoroacetic anhydride, and trifluoromethanesulfonic acid. The mixture was stirred at 70 °C for 1 hour under atmospheric pressure and nitrogen atmosphere, maintaining the temperature below 5 °C. 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 the polymer, which was then filtered. The filtered polymer was washed twice with distilled water and twice with ethanol. The polymer was then dried under vacuum at 150 °C for 8 hours. The molecular weight was measured using GPC, revealing 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.

[0100] (Comparative Example 4) Monomer Preactivation Method A four-neck separable flask equipped with a nitrogen inlet tube, thermometer, reflux condenser, and stirrer was charged with 35 g of terephthalic acid, 15 g of isophthalic acid, 170 g of trifluoromethanesulfonic acid, and 158 g of trifluoroacetic anhydride. The mixture was stirred at 25°C for 2 hours under atmospheric pressure and nitrogen atmosphere (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 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 Mn was 8300, 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.

[0101] (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 atmospheric pressure for 2 hours (first reaction). A separate separable flask was charged with 48 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was stirred at 25°C under a nitrogen atmosphere at atmospheric 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 to precipitate a polymer, which was then filtered. The filtered polymer was 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.

[0102] (Comparative Example 6) 102 g of diphenyl sulfone, 18.5 g of 1,3-bis(4'-hydroxybenzoyl)benzene, 6.36 g of Na2CO3, and 0.040 g of K2CO3 were added to a four-neck reaction flask. The flask was equipped with a stirrer, a N2 inlet tube, a Claisen adapter with a thermocouple in 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 O2). 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 Na2CO3, and 0.029 g of K2CO3 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, 1.29g of 1,4-bis(4'-fluorobenzoyl)benzene was added to the reaction mixture while maintaining a nitrogen purge in the flask. After 5 minutes, 0.427g of lithium chloride was added to the reaction mixture. After 10 minutes, another 0.323g 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 tray 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) had been obtained. The resulting PEKK polymer was analyzed as described above. The synthesis parameters and analytical results are shown in Table 3.

[0103] (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.

[0104] (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.

[0105] (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. Under atmospheric pressure and a nitrogen atmosphere, 102 g of anhydrous aluminum trichloride was added and the mixture was stirred at 0°C for 30 minutes. 1,000 g of o-dichlorobenzene was then 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 the 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, revealing that the Mn was 8,000, confirming the formation of a PAEK resin (PEKK polymer). The resulting PEKK polymer was analyzed as described above, and the results are shown in Table 3.

[0106] (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 for 2 hours under a nitrogen atmosphere at atmospheric pressure (first reaction). A separate separable flask was charged with 19 g of terephthalic acid, 29 g of isophthalic acid, 135 g of trifluoromethanesulfonic acid, and 151 g of trifluoroacetic anhydride, and the mixture was stirred at 40°C for 2 hours under a nitrogen atmosphere at atmospheric pressure (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 to precipitate a polymer, which was then filtered. The filtered polymer was 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 confirmed that Mn was 4500, and 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.

[0107] [Table 1]

[0108] [Table 2]

[0109] [Table 3]

[0110] In Table 1, repeating unit 5-1 and repeating unit 5-2 have the following structures. [ka]

change

Claims

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; 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 solution; A method for producing a polyarylene ether ketone resin, comprising: 【Chemistry 1】 【Chemistry 2】

2. The method for producing a polyarylene ether ketone resin according to claim 1, wherein in the step (II), the temperature at which the oligomer is pre-dissolved is 20°C or higher and 150°C or lower.

3. The method for producing a polyarylene ether ketone resin according to claim 1 or 2, wherein in the step (II), the time for pre-dissolving the oligomer is from 1 minute to 6 hours.

4. The method for producing a polyarylene ether ketone resin according to any one of claims 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 claims 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 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): 【Transformation 3】 (R in the formula １ and R ２ may be the same or different and are 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 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): 【Chemistry 4】 (R in the formula １ and R ２ may be the same or different and are a hydrogen atom, a fluorine atom, a trifluoromethyl group, a pentafluoroethyl group, or an alkyl group having 1 to 8 carbon atoms. 【Transformation 5】

8. 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.

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