Aromatic ether ketone resin compositions, methods for manufacturing the same, molded articles thereof, and methods for improving the retention stability of the melt viscosity of the resin compositions.

Abstract

A fully aromatic ether ketone resin composition comprising: (A) a specific fully aromatic ether ketone resin, and (B) a salt formed by an acid and a base, wherein the pH obtained by pH determination according to the following method is 6-8: [pH determination method] (a) Add 5 mL of acetone to 10 g of the powdered fully aromatic ether ketone resin composition, then add 100 mL of pure water, stir for 10 minutes, and then filter. (b) Add 0.1 mL of pure water dropwise to the residue generated by evaporating the liquid components of the obtained filtrate. (c) Set the temperature to 25°C, bring the added pure water into contact with pH test paper, and measure the pH.

Description

[Technical Field]

[0001] This invention relates to a resin composition comprising polyetherketone, polyetheretherketone, or polyetherketone etherketone ketone, etc., a method for manufacturing the same, a molded article formed from the resin composition, and a method for improving the retention stability of the melt viscosity of the resin composition. [Previous Technology]

[0002] Fully aromatic ether ketone resins, also abbreviated as PAEK (polyaryl ether ketone), PEEK (poly(ether ether ketone), polyether ether ketone), PEK (poly(ether ketone), polyether ketone), PEKK (poly(ether ketone ketone), polyether ketone ketone), PEKEKK (poly(ether ketone ether ketone ketone), polyether ketone ether ketone ketone), etc., are commercially available. Since fully aromatic ether ketone resins generally have high melting points (over 300°C), they must be heated to high temperatures to melt. However, at such high temperatures, there is a lack of stability against thermal degradation. Therefore, various countermeasures have been taken to stabilize the molten state (see Patent Documents 1 and 2). The resin compositions described in Patent Documents 1 and 2 achieve stabilization against thermal oxidation in the molten state by adding phosphates or mixtures of phosphates. [Prior Art Documents] [Patent Documents]

[0003] Patent Document 1: Japanese Patent No. 2018-520257; Patent Document 2: Japanese Patent No. 2018-520258 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] On the other hand, it is known that the viscosity of fully aromatic ether ketone resins increases with residence time in the molten state. This increase in viscosity is presumably caused by cross-linking due to oxidation at very high processing temperatures (over 350°C) of the fully aromatic ether ketone resin. Although the resin compositions described in Patent Documents 1 and 2 are intended to stabilize for thermal oxidation in the molten state, the increase or decrease in viscosity with residence time is due to many factors, including: the reaction of residual reactive ends with each other, oxidative cross-linking, molecular chain elongation caused by side effects caused by residual catalysts, molecular chain breakage caused by heat, oxygen, residual impurities, etc. Stabilizing for thermal oxidation alone cannot improve the residence stability of the molten viscosity.

[0006] This invention was made in view of the aforementioned problems, and its objective is to provide a fully aromatic ether ketone resin composition with good retention stability of melt viscosity, a method for manufacturing the same, a molded article thereof, and a method for improving the retention stability of the melt viscosity of the resin composition. [Means for solving the problem]

[0007] As a result of careful research by the inventors in order to solve the above-mentioned problems, it was discovered that by adjusting the pH of the all-aromatic ether ketone resin composition to a specific range, the retention stability of the melt viscosity can be improved, and thus the present invention was completed.

[0008] An embodiment of the present invention that solves the above-mentioned problems is described below. (1) A fully aromatic ether ketone resin composition comprising: (A) a fully aromatic ether ketone resin, and (B) a salt formed by an acid and a base, wherein the pH obtained by pH determination according to the following pH determination method is 6 to 8, wherein the fully aromatic ether ketone resin (A) is selected from one or more of the group consisting of polyether ketone, polyether ether ketone and polyether ketone ether ketone, [pH determination method] (a) 5 mL of acetone is added to 10 g of the powder of the fully aromatic ether ketone resin composition, followed by 100 mL of pure water, and the mixture is stirred for 10 minutes and then filtered; (b) 0.1 mL of pure water is added dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a); (c) The temperature is set to 25°C, and the pure water added dropwise to the residue in (b) is brought into contact with pH test paper to determine the pH.

[0009] (2) The fully aromatic ether ketone resin composition described in (1) above, wherein the pH of the salt formed by the acid and the base in (B) above is 4 to 9.

[0010] (3) The fully aromatic ether ketone resin composition described in (1) or (2) above, wherein the fully aromatic ether ketone resin in (A) above is polyether ketone.

[0011] (4) The fully aromatic ether ketone resin composition described in any one of (1) to (3) above, wherein the salt formed by the acid and the base in (B) above is at least one of the phosphates.

[0012] (5) A molded article formed from the fully aromatic ether ketone resin composition described in any one of (1) to (4) above.

[0013] (6) A method for manufacturing a fully aromatic ether ketone resin composition, comprising adding at least (A) a fully aromatic ether ketone resin, (B) an acid and a base, or at least one of a salt formed by an acid and a base, and adjusting the pH obtained by pH determination according to the following pH determination method to a pH of 6 to 8, [pH determination method] (a) adding 5 mL of acetone to 10 g of the powder of the fully aromatic ether ketone resin composition, then adding 100 mL of pure water, stirring for 10 minutes, and then filtering. (b) adding 0.1 mL of pure water to the residue generated by evaporating the liquid components of the filtrate obtained by (a) above. (c) setting the temperature to 25°C, contacting the pure water added to the residue in (b) above with pH test paper, and measuring the pH.

[0014] (7) A method for improving the retention stability of the melt viscosity of a fully aromatic ether ketone resin composition, wherein the fully aromatic ether ketone resin composition contains one or more (A) fully aromatic ether ketone resins selected from the group consisting of polyether ketone, polyether ether ketone, and polyether ketone ether ketone ketone, and (B) a salt formed by an acid and a base is added to the above fully aromatic ether ketone resin composition so that the pH obtained by pH determination according to the following pH determination method is 6 to 8, [pH determination method] (a) 5 mL of acetone is added to 10 g of the powder of the fully aromatic ether ketone resin composition, followed by 100 mL of pure water, and the mixture is stirred for 10 minutes, and then filtered; (b) 0.1 mL of pure water is added dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a) above; (c) The temperature is set to 25°C, and the pure water added dropwise to the residue in (b) above is brought into contact with pH test paper to determine the pH. [Effects of the Invention]

[0015] According to the present invention, a fully aromatic ether ketone resin composition with good retention stability of melt viscosity and a method for manufacturing the same, a molded article thereof, and a method for improving the retention stability of the melt viscosity of the resin composition are provided.

Implementation Method

[0017] [Form for implementing the invention]

[0018] <Fully Aromatic Ether Ketone Resin Composition> The fully aromatic ether ketone resin composition of this embodiment (hereinafter also simply referred to as the "resin composition") comprises: (A) a fully aromatic ether ketone resin, and (B) a salt formed by an acid and a base. The pH obtained by measuring the pH using the pH measurement method described below is 6 to 8. Furthermore, (A) the fully aromatic ether ketone resin is one or more selected from the group consisting of polyether ketone, polyether ether ketone, and polyether ketone ether ketone ketone. [pH Measurement Method] (a) Add 5 mL of acetone to 10 g of the powder of the fully aromatic ether ketone resin composition, then add 100 mL of pure water, stir for 10 minutes, and then filter. (b) Add 0.1 mL of pure water dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a). (c) Set the temperature to 25°C, and bring the pure water dropwise added to the residue in (b) into contact with pH test paper to measure the pH.

[0019] Because the fully aromatic ether ketone resin composition of this embodiment can improve the retention stability of melt viscosity by adjusting the pH to the range of 6 to 8 using (B) a salt formed by acid and base. The mechanism is speculated as follows. Although two polymerization methods for fully aromatic ether ketone resins can be listed, namely (1) nucleophilic aromatic substitution reaction and (2) Friedel-Crafts Acylation, in this embodiment, the polymerized by (1) nucleophilic aromatic substitution reaction is used. In other words, polyetherketone, polyetheretherketone, and polyetherketone etherketone ketone, which are fully aromatic ether ketone resins (A), are all polymerized by (1) nucleophilic aromatic substitution reaction. The fully aromatic ether ketone resin polymerized by (1) nucleophilic aromatic substitution reaction is polymerized under high temperature (above 300°C) and alkaline conditions with phenolic hydroxyl groups and aromatic halogens as reactive groups. Polymerization is typically halted by disrupting the end-effector equilibrium through a terminal blocking reaction (Japanese Patent Application Publication No. 61-138626). Alkali metal salts, which can be used as alkaline catalysts, can be removed by a post-polymerization water washing step. From the polymerization mechanism, it is understood that if conditions such as a low terminal blocking reaction rate and the presence of residual alkaline catalyst overlap, reactive terminals will polymerize against each other during melt retention, leading to an increase in molecular weight and viscosity. Therefore, in this embodiment, it is intended to suppress the reaction caused by the functional groups at the polymerized ends within a specific pH range of the resin composition, thereby improving the retention stability of the melt viscosity.

[0020] On the other hand, regarding the pH measurement method, specific conditions will be further explained. For the stirring in (a) above, a general method that can uniformly stir within the system, such as using a magnetic stirrer or mechanical stirrer, is preferred. Furthermore, for the filtration in (b) above, a general material that does not leach and can separate solids and liquids is preferred as the filter material. Moreover, for the pH test paper used in (c) above, any material capable of measuring at least pH 1 to 11 is acceptable. Hereinafter, the components of the all-aromatic ether ketone resin composition of this embodiment will be described in detail.

[0021] [(A) Fully Aromatic Etherketone Resin] The fully aromatic resin composition of this embodiment, as (A) fully aromatic etherketone resin, contains one or more resins selected from the group consisting of polyetherketone (PEK), polyetheretherketone (PEEK), and polyetherketone etherketone ketone (PEKEKK). Since these fully aromatic etherketone resins are polymerized by (1) nucleophilic aromatic substitution reaction, they are alkaline. From this point of view, the pH of the fully aromatic etherketone resin itself is preferably 9 to 12. Polyetherketone (PEK) is preferred as (A) fully aromatic etherketone resin.

[0022] As described above, two methods for polymerizing fully aromatic ether ketone resins can be listed: (1) nucleophilic aromatic substitution reaction and (2) Friedel-Crafts acetylation reaction. In the specific examples above, usually only polyether ketone ketone (PEKK) is polymerized by (2) Friedel-Crafts acetylation reaction. This type of polyether ketone ketone (PEKK) is neutral.

[0023] [(B) Salt formed from acid and base] In this embodiment, (B) salt formed from acid and base (hereinafter also referred to as "(B) component") is used to adjust the pH of the resin composition to 6-8. When the pH of the resin composition exceeds 8, the melt viscosity increases due to retention; when the pH is below 6, the melt viscosity decreases due to retention, resulting in poor retention stability of the melt viscosity. The pH is preferably 6-7, and more preferably 7. Furthermore, when adjusting the pH of the resin composition to 6-8, two or more (B) components may be used.

[0024] As described above, when adjusting the pH of the resin composition to 6-8, it is preferable to use a component with a pH of 4-9 as component (B). Furthermore, when component (B) is a mixture of two or more components, it is acceptable as long as the pH of the mixture is within the range of 4-9, even if the pH of at least one component is not 4-9.

[0025] The acid and base used as sources of component (B) are not particularly limited as long as the pH of the resin composition can be adjusted to 6-8. Examples of acids used as sources of component (B) include phosphoric acid and sulfuric acid. Examples of bases used as sources of component (B) include alkali metal hydroxides such as sodium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, and magnesium hydroxides; and ammonia. Examples of components (B) include, for example, at least one type of phosphate, ammonium sulfate, etc., with at least one type of phosphate being preferred. Examples of phosphates include, for example, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, calcium dihydrogen phosphate, calcium hydrogen phosphate, magnesium dihydrogen phosphate, magnesium hydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.

[0026] The content of component (B) can be set to make the pH of the resin composition 6 to 8, and can be 200 to 2000 ppm.

[0027] [Other Components] In this embodiment, if necessary, one or more common additives may be added to the thermoplastic resin, such as lubricants, release agents, antistatic agents, surfactants, flame retardants, or organic polymer materials, inorganic or organic powdered or sheet-like fillers, etc. However, even if other components are added, the pH of the resin composition must still be in the range of 6 to 8.

[0028] <Molded Article> The molded article of this embodiment is formed by molding the fully aromatic ether ketone resin composition of this embodiment described above. Because the molded article has good retention stability of melt viscosity, it remains stable and can be used even when exposed to high temperatures for a long time, such as injection molding or solid-phase extrusion with long residence time.

[0029] There are no particular limitations on the method for producing molded articles using the fully aromatic ether ketone resin composition of this embodiment, and known methods can be used. For example, the fully aromatic ether ketone resin composition of this embodiment can be fed into an extruder, melt-mixed and granulated, and the granules can be fed into an injection molding machine equipped with a predetermined mold for injection molding to produce the product.

[0030] As a molded article of this embodiment, it can be used as an automobile, aerospace, heavy industry (steel, power plant), electronic component, etc.

[0031] <Method for Manufacturing a Fully Aromatic Ether-Ketone Resin Composition> The method for manufacturing a fully aromatic ether-ketone resin composition according to this embodiment includes adding at least (A) a fully aromatic ether-ketone resin, and (B) an acid and a base, or at least one of a salt formed from an acid and a base, and adjusting the pH obtained by measuring according to the pH measurement method below to 6-8. [pH Measurement Method] (a) Add 5 mL of acetone to 10 g of the powder of the fully aromatic ether-ketone resin composition, then add 100 mL of pure water, stir for 10 minutes, and then filter. (b) Add 0.1 mL of pure water dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a). (c) Set the temperature to 25°C, and bring the pure water dropwise added to the residue in (b) into contact with pH test paper to measure the pH.

[0032] In the manufacturing method of this embodiment, similarly to the resin composition of this embodiment described above, the pH of the resin composition is adjusted to 6-8 by adding at least (A) a fully aromatic ether ketone resin and (B) an acid and a base, or at least one of a salt formed from an acid and a base. By adjusting the pH of the resin composition to 6-8, as described above, the retention stability of the melt viscosity is good.

[0033] In the manufacturing method of this embodiment, when adjusting the pH of the resin composition, at least one of (B) acid and base, or salt formed by acid and base, is used. Among these, the salt formed by acid and base (hereinafter, "salt A") is the same as the salt formed by acid and base contained in the resin composition of this embodiment, so it is omitted here. Only the acid and base will be described below.

[0034] The combination of acid and base added in the manufacturing method of this embodiment is selected such that, after neutralization, they become the aforementioned salt A. For example, when salt A is sodium dihydrogen phosphate, the acid and base are a combination of phosphoric acid and sodium hydroxide; when salt A is sodium acetate, the acid and base are a combination of acetic acid and sodium hydroxide. In other words, when an acid and base are added to a fully aromatic ether ketone resin, the acid and base generate salt A through a neutralization reaction during blending. When salt A is generated, it exhibits the effect of good retention stability of so-called melt viscosity.

[0035] The amount of acid and base added is set such that the pH of the salt formed after the neutralization of the acid and base is in the same range as that of salt A mentioned above.

[0036] <Method for improving the retention stability of melt viscosity of a fully aromatic ether ketone resin composition> The method for improving the retention stability of melt viscosity of a fully aromatic ether ketone resin composition of this embodiment (hereinafter, abbreviated as "method for improving retention stability") is a method for improving the retention stability of melt viscosity of a fully aromatic ether ketone resin composition containing one or more fully aromatic ether ketone resins selected from the group consisting of (A) polyether ketone resins, polyether ether ketone, and polyether ketone ether ketone ketone. Then, a salt formed by an acid and a base (B) is added to the all-aromatic ether ketone resin composition to make the pH obtained by pH determination according to the following method 6 to 8. [pH determination method] (a) Add 5 mL of acetone to 10 g of the powder of the all-aromatic ether ketone resin composition, then add 100 mL of pure water, stir for 10 minutes, and then filter; (b) Add 0.1 mL of pure water to the residue generated by evaporating the liquid components of the filtrate obtained by (a) above; (c) Set the temperature to 25°C, and bring the pure water added to the residue in (b) above into contact with pH test paper to measure the pH.

[0037] In the fully aromatic ether ketone resin composition of this embodiment described above, by keeping the pH within a specific range, the reaction caused by the terminal functional groups after polymerization is suppressed, thereby improving the retention stability of the melt viscosity. In other words, by keeping the pH of the resin composition within a specific range, the retention stability of the melt viscosity can be improved. Therefore, in the method for improving the retention stability of this embodiment, by adding (B) a salt formed from an acid and a base, and by keeping the pH obtained by measuring according to the above pH measurement method at 6 to 8, the retention stability of the melt viscosity can be improved.

[0038] In the method for improving retention stability in this embodiment, (A) the all-aromatic ether ketone resin is one or more selected from the group consisting of polyether ketone, polyether ether ketone, and polyether ketone ether ketone ketone. Since its detailed description is as described above, it is omitted here. Furthermore, (B) the salt formed from the acid and base is also as described in the all-aromatic ether ketone resin composition of this embodiment, and is therefore omitted here. Other preferred examples and content ranges of each component also directly apply to the descriptions in the all-aromatic ether ketone resin composition of this embodiment described above. [Example]

[0039] Hereinafter, although the present embodiment is further described in detail by way of examples, the present embodiment is not limited to the following examples.

[0040] [Examples 1-6, Comparative Examples 1-5] In each example and comparative example, the raw material components shown in Table 1 were blended in the proportions shown in Table 1 to obtain a powder of a fully aromatic ether ketone resin composition. Furthermore, (B) a salt formed from an acid and a base was added in the form of an aqueous solution (solvent: distilled water, concentration: 2000 ppm / mL). Details of each raw material component used are shown below.

[0041] (A) Aromatic ether ketone resin. Polyether ketone (PEK) was polymerized according to the manufacturing method described in Japanese Patent Application Publication No. 2009-227961 to obtain polyether ketone powder. The pH of the obtained polyether ketone powder was 10. Furthermore, the pH of the aromatic ether ketone resin was measured in the same manner as the pH determination method for the following aromatic ether ketone resin composition.

[0042] (B) Salts formed by acids and bases. Sodium dihydrogen phosphate (dual hydrate); pH: 4. Disodium hydrogen phosphate (anhydrous); pH: 9. Trisodium phosphate (dihydrate); pH: 12. Potassium dihydrogen phosphate; pH: 4. Dipotassium hydrogen phosphate; pH: 9. Ammonium dihydrogen phosphate; pH: 4. Ammonium sulfate; pH: 4.

[0043] [Evaluation] (1) pH In 10g of the powder of the all-aromatic ether ketone resin composition obtained in each example and comparative example, 5mL of acetone was added, followed by 100mL of pure water. The mixture was stirred for 10 minutes and then filtered. 0.1mL of pure water was added dropwise to the residue generated by evaporating the liquid components of the obtained filtrate. The temperature was set to 25°C, and the pure water added to the residue was brought into contact with pH test paper to measure the pH. The measured pH values ​​are shown in Tables 1 and 2.

[0044] (2) The melt viscosity retention rate will be determined by weighing 0.8 g of the powder of the all-aromatic ether ketone resin composition obtained in each example and comparative example at 140°C for 9 hours in the center of a circular mold made of SUS304 (outer diameter: 50 mm, inner diameter: 21 mm, thickness: 2 mm), and then pressing it under the following molding conditions using a vacuum hot pressurization device (made by Imoto Manufacturing Co., Ltd.) to obtain a test piece for testing. [Molding conditions] Heating plate temperature: 400°C Preheating time: 3 minutes Pressurization pressure: 10 tons Pressurization time: 30 seconds.

[0045] For the obtained test piece, the complex viscosity in the molten state was measured using a rheometer (TA Instruments, Discovery HR-3) under the following measurement conditions, and the retention rate of the molten viscosity was calculated according to the following formula (I). The calculated retention rate of the molten viscosity is expressed in Tables 1 and 2. Retention rate of molten viscosity (%) = [(complex viscosity at 30 minutes) / (complex viscosity at 5 minutes)] × 100... (I) [Measurement conditions] Plate diameter: 25 mm Gap spacing: 1000 μm Measurement temperature: 400 °C Measurement mode: Vibration Measurement Ambient gas: Nitrogen Measurement time: 5 to 30 minutes Measurement range: 100 rad / s.

[0046] (3) The retention stability of melt viscosity was evaluated based on the retention rate of melt viscosity calculated in each embodiment and comparative example. In other words, a melt viscosity retention rate of 95% to 105% was rated as "good", and a retention rate of less than 95% or more than 105% was rated as "poor". A "good" evaluation result indicates good retention stability of melt viscosity. The evaluation results are shown in Table 1 and Table 2.

[0047] [Table 1] Example Example Example Example Example Example 1 2 3 4 5 6 (A) Fully aromatic ether-ketone resin Polyetherketone g 5.0 5.0 5.0 5.0 5.0 5.0 pH - 10 10 10 10 10 10 (B) Salts formed by acids and bases Sodium dihydrogen phosphate ppm 500 250 1000 - - - disodium hydrogen phosphate ppm - 250 1000 - - - Trisodium phosphate ppm - - - - - - Potassium dihydrogen phosphate ppm - - - 250 - - dipotassium hydrogen phosphate ppm - - - 250 - - Ammonium dihydrogen phosphate ppm - - - - 200 - ammonium sulfate ppm - - - - - 400 pH - 4 7 7 7 4 4 All-aromatic ether ketone resin composition pH - 6 7 7 7 7 6 Melt viscosity retention rate % 96 101 98 102 103 98 Retention stability of melt viscosity - good good good good good good

[0048] [Table 2] Comparative example Comparative example Comparative example Comparative example Comparative example 1 2 3 4 5 (A) Fully aromatic ether-ketone resin Polyetherketone g 5.0 5.0 5.0 5.0 5.0 pH - 10 10 10 10 10 (B) Salts formed by acids and bases Sodium dihydrogen phosphate ppm - 3000 - - - disodium hydrogen phosphate ppm - - 500 - - Trisodium phosphate ppm - - - 500 - Potassium dihydrogen phosphate ppm - - - - - dipotassium hydrogen phosphate ppm - - - - - Ammonium dihydrogen phosphate ppm - - - - 600 ammonium sulfate ppm - - - - - pH - - 4 9 12 4 All-aromatic ether ketone resin composition pH - 10 4 10 12 5 Melt viscosity retention rate % 115 88 110 115 83 Retention stability of melt viscosity - bad bad bad bad bad

[0049] As can be seen from Tables 1-2, Examples 1-6, in which the pH range of the all-aromatic ether ketone resin compositions is 6-8, all exhibit excellent retention stability of melt viscosity. In contrast, Comparative Examples 1-5, in which the pH range of the all-aromatic ether ketone resin compositions is outside the range of 6-8, exhibit poor retention stability of melt viscosity. [Simplified Explanation of the Diagram]

[0016] None.

Claims

1. A fully aromatic ether ketone resin composition comprising: (A) a fully aromatic ether ketone resin, and (B) a salt formed by an acid and a base, wherein the pH obtained by pH determination according to the following pH determination method is 6-8, wherein the (A) fully aromatic ether ketone resin is polymerized by a nucleophilic aromatic substitution reaction, and is selected from one or more of the group consisting of polyether ketone, polyether ether ketone, and polyether ketone ether ketone ketone, [pH determination method] (a) 5 mL of acetone is added to 10 g of the powder of the fully aromatic ether ketone resin composition, followed by 100 mL of pure water, and the mixture is stirred for 10 minutes, and then filtered; (b) 0.1 mL of pure water is added dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a); (c) The temperature is set to 25°C, and the pure water added to the residue in (b) is brought into contact with pH test paper to determine the pH.

2. The all-aromatic ether ketone resin composition as described in claim 1, wherein, The pH of the salt formed by the acid and the base in (B) above is 4 to 9.

3. The all-aromatic ether ketone resin composition as described in claim 1 or 2, wherein, The above-mentioned (A) all-aromatic ether ketone resin is polyether ketone.

4. The all-aromatic ether ketone resin composition as described in claim 1 or 2, wherein, The salt formed by the acid and the base in (B) above is at least one of the phosphates.

5. A molded article formed from the fully aromatic ether ketone resin composition described in any one of claims 1 to 4.

6. A method for manufacturing a fully aromatic ether ketone resin composition, comprising adding at least one of an acid and a base, or a salt formed from an acid and a base, to a (A) fully aromatic ether ketone resin polymerized by a nucleophilic aromatic substitution reaction, and adjusting the pH obtained by pH determination according to the following pH determination method to a pH of 6 to 8: [pH determination method] (a) Adding 5 mL of acetone to 10 g of the powder of the fully aromatic ether ketone resin composition, then adding 100 mL of pure water, stirring for 10 minutes, and then filtering; (b) Adding 0.1 mL of pure water dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a) above; (c) Setting the temperature to 25°C, contacting the pure water dropwise added to the residue in (b) above with pH test paper, and measuring the pH.

7. A method for improving the retention stability of the melt viscosity of a fully aromatic ether ketone resin composition, the fully aromatic ether ketone resin composition containing one or more (A) fully aromatic ether ketone resins polymerized by nucleophilic aromatic substitution reaction and selected from the group consisting of polyether ketone, polyether ether ketone, and polyether ketone ether ketone ketone; adding (B) a salt formed by an acid and a base to the above fully aromatic ether ketone resin composition, so that the pH obtained by pH determination according to the following pH determination method is 6 to 8, [pH determination method] (a) adding 5 mL of acetone to 10 g of the powder of the fully aromatic ether ketone resin composition, then adding 100 mL of pure water, stirring for 10 minutes, and then filtering; (b) adding 0.1 mL of pure water dropwise to the residue generated by evaporating the liquid components of the filtrate obtained by (a) above; (c) setting the temperature to 25°C, contacting the pure water dropwise added to the residue in (b) above with pH test paper, and measuring the pH.