Method for producing aromatic polyether powder

Abstract

To provide an improved method for producing an aromatic polyether powder.SOLUTION: There is provided a method for producing an aromatic polyether powder, which comprises a granulation step in which an aromatic polyether and a first organic solvent is mixed with a second organic solvent in which the first organic solvent is soluble to obtain a granulated product in which the aromatic polyether is solidified, wherein in the granulation step, the temperature of the second organic solvent is lower than the temperature of the mixed liquid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a novel aromatic polyether powder. Specifically, the present invention relates to an improved method for producing an aromatic polyether powder.

Background Art

[0002] Aromatic polyethers have excellent heat resistance and mechanical strength and are used as metal substitute materials because of these characteristics. In recent years, their applications have been expanded to fields such as automobiles, aircraft, and medicine. Among them, polyetheretherketone (abbreviation "PEEK"), which is a kind of aromatic polyether, is produced under carbonate using hydroquinone and halogenated diphenyl ketone as main components. At that time, since metal halides and the like are by-produced simultaneously with the production of PEEK, the reaction product contains the raw material carbonate and the by-produced metal halide. Usually, as a method for treating these reaction mixtures, a process of cooling and solidifying using a belt cooler or the like, subsequently performing pulverization using a pulverizer, a mill or the like, and then purifying using an organic solvent, water or the like is introduced (Non-Patent Document 1, Patent Document 1). Also, a method of directly injecting a high-temperature reaction solution into water to form particles is known (Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors have found that there is room for improvement in the conventional method for producing PEEK, particularly in the process of treating the reaction mixture.

[0006] In the method of mechanical pulverization after cooling and solidification in Non-Patent Document 1, since the cooled and solidified product comes into direct contact with the rotating part of the equipment during pulverization, contamination with metal elements and the like was a concern. Also, depending on the shape of the solidified product, there was a possibility that it would be necessary to deal with problems in transportation such as clogging, bridging, and scattering of dust.

[0007] In the method of Patent Document 1, a cooling and solidification step and a pulverization step using a mill or the like were required, and the operation was complicated. Also, the methods of Patent Documents 2 and 3 are methods of directly dispersing a high-temperature reaction solution in water. However, when granulating and solidifying in water, lumps are likely to form. Therefore, it was necessary to use special equipment having a high-speed rotating part such as a chopper in addition to a normal agitator. Furthermore, when granulating with water, the granulated particles need to have the solvent washed away with an organic solvent. In addition to the granulation step, a step for removing the solvent by washing with an organic solvent was required, which was complicated.

[0008] Therefore, as a result of intensive studies, the present inventors have found that by mixing a mixed solution containing an aromatic polyether and a first organic solvent with a second organic solvent in which the first organic solvent is soluble, a granulation step of obtaining a granulated product in which the aromatic polyether is solidified is included. In the granulation step, when the temperature of the second organic solvent is lower than the temperature of the mixed solution, a mechanical pulverization step using a mill or the like is not required, the cooling and solidification step and the pulverization step can be simplified, and it is not necessary to use special equipment having a high-speed rotating part, and an aromatic polyether powder can be obtained, thus completing the present invention.

[0009] One object of the present invention is to provide an improved method for producing aromatic polyether powder. Specifically, an object of the present invention is to provide a method for producing aromatic polyether powder that does not require a mechanical pulverization step using a mill or the like, can simplify the cooling and solidification step and the pulverization step, and does not require the use of special equipment having a high-speed rotating part.

Means for Solving the Problems

[0010] According to the present invention, there is provided a method for producing the following aromatic polyether powder. 1. A granulation step of mixing a mixed solution containing an aromatic polyether and a first organic solvent with a second organic solvent in which the first organic solvent is soluble to obtain a granulated product in which the aromatic polyether is solidified, In the granulation step, a method for producing aromatic polyether powder, wherein the temperature of the second organic solvent is lower than the temperature of the mixed solution. 2. The method for producing aromatic polyether powder according to item 1 above, wherein the distance Ra between the Hansen solubility parameter of the first organic solvent at 25°C and the Hansen solubility parameter of the second organic solvent at 25°C is 20 or less. 3. The method for producing aromatic polyether powder according to item 1 or 2 above, wherein the first organic solvent is diphenyl sulfone. 4. The method for producing aromatic polyether powder according to any one of items 1 to 3 above, wherein the second organic solvent is soluble in water. 5. The method for producing the aromatic polyether powder according to any one of 1 to 4 above, wherein the temperature of the second organic solvent is 5°C to 160°C. 6. The method for producing the aromatic polyether powder according to any one of 1 to 5 above, wherein the aromatic polyether contains a structural unit represented by the following formula (1). [Chemical formula] [In formula (1), A includes one or more selected from the group consisting of the following formulas (A1) to (A3). [Chemical formula] (In formula (A1), X A1 represents -C(=O)- or -S(=O)2-. In formula (A2), X A2 and X A3 each independently represent -C(=O)- or -S(=O)2-. In formula (A3), R A represents a cyano group.) B includes one or more selected from the group consisting of the following formulas (B1) to (B3). [Chemical formula] (In formula (B1), R B represents a hydrogen atom or a phenyl group.) n is an integer from 0 to 2. When n is 0, the oxygen atom is directly bonded to the adjacent unit structure. When n is 1, B is directly bonded to the adjacent unit structure. When n is 2, among the two Bs, the B farthest from A is directly bonded to the adjacent unit structure.) [Advantages of the Invention]

[0011] According to the present invention, an improved method for producing an aromatic polyether powder can be provided. [Brief Description of the Drawings]

[0012]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0013] Hereinafter, the method for producing an aromatic polyether powder of the present invention will be described in detail. In this specification, "x to y" represents a numerical range of "x or more and y or less". The upper limit value and the lower limit value described for the numerical range can be arbitrarily combined.

[0014] [Method for Producing Aromatic Polyether Powder] A method for producing an aromatic polyether powder according to one aspect of the present invention (hereinafter, also referred to as "the production method of the present invention") includes a granulation step of mixing a mixed solution containing an aromatic polyether and a first organic solvent with a second organic solvent in which the first organic solvent is soluble to obtain a granulated product in which the aromatic polyether is solidified. In the granulation step, the temperature of the second organic solvent is lower than the temperature of the mixed solution.

[0015] [Granulation Step] By mixing a mixed solution containing an aromatic polyether and a first organic solvent with a second organic solvent in which the first organic solvent is soluble, the aromatic polyether is granulated, and if necessary, the granulated product is washed and dried to obtain an aromatic polyether powder. In this specification, that the first organic solvent is soluble in the second organic solvent means that the first organic solvent and the second organic solvent are miscible.

[0016] The mode of mixing the mixed solution and the second organic solvent is not particularly limited, and the mixed solution may be added to the second organic solvent, or the second organic solvent may be added to the mixed solution.

[0017] In the granulation process, the temperature of the second organic solvent is lower than the temperature of the mixed solution.

[0018] Thereby, while cooling and solidifying the aromatic polyether solution, it becomes easier to obtain a powder having a desired particle size. Although not limited by theory, since the aromatic polyether is dissolved in the first organic solvent and solid-liquid separation by filtration or the like cannot be performed, the first organic solvent and the second organic solvent are miscible, so that the aromatic polyether and the first organic solvent are separated, and it is considered that the aromatic polyether can be prevented from forming coarse solids together with the first organic solvent. From the viewpoint of making the granulated product finer, it is desirable to quickly mix the first organic solvent and the second organic solvent.

[0019] By using this method, it is considered that a part or almost all of the first organic solvent can be removed from the mixed solution containing the aromatic polyether and the first organic solvent simultaneously with granulation, reducing the two steps of the granulation process and the washing process of the first organic solvent to one step, or reducing the load of the washing process of the first organic solvent.

[0020] Further, according to the method for producing an aromatic polyether powder according to this embodiment, by mixing a mixed solution containing an aromatic polyether and a first organic solvent with a second organic solvent to granulate the aromatic polyether, a mechanical pulverization process using a mill or the like is not required, the cooling and solidification process and the pulverization process can be simplified, and an aromatic polyether powder can be easily obtained without using special equipment having a high-speed rotating part.

[0021] In other words, according to the above granulation process, while simultaneously performing a part of the washing process of the first organic solvent, the cooling and solidification process of the aromatic polyether, and the pulverization process, a granulated product containing the aromatic polyether can be formed, and the post-treatment of granulation of the aromatic polyether can be simplified.

[0022] The manufacturing method of the aromatic polyether powder according to the present aspect does not exclude including further processing steps such as a washing step, a pulverizing step, or a drying step, etc. additionally after the granulation step. Depending on the state of the obtained granulated product and the characteristics of the target aromatic polyether powder, additional treatments such as washing, pulverizing, or drying may be carried out.

[0023] In this specification, "powder" is an aggregate of a plurality of fine solids. The powder preferably has a particle size of 100 nm to 3 mm as a guide. The powder may be the granulated product itself, or it may be the granulated product that has been sieved, crushed, or pulverized and dried as necessary. The shape of the powder can be appropriately selected regardless.

[0024] The particle size of the powder is preferably 1000 μm or less in terms of the median diameter D 50 For example, it is 500 μm or less, 250 μm or less, 100 μm or less, or 50 μm or less.

[0025] The particle size of the powder is preferably 1 to 1000 μm in terms of the median diameter D 50 For example, it is 5 to 250 μm, or 10 to 50 μm. The particle size of the powder can be measured by the method described in the examples using a laser diffraction particle size distribution analyzer.

[0026] When the particle size of the powder is 10 to 50 μm in terms of the median diameter D 50 it is easy to efficiently perform treatments such as washing, pulverizing, or drying.

[0027] The particle size of the powder is preferably 3000 μm or less in terms of the median diameter D 90 For example, it is 2000 μm or less, 1000 μm or less, 500 μm or less, 250 μm or less, or 100 μm or less.

[0028] The particle size of the powder is preferably 10 to 3000 μm in terms of the median diameter D 90 For example, it is 20 to 2000 μm, or 50 to 100 μm.

[0029] [Mixture solution] In a method for producing an aromatic polyether according to one embodiment of the present invention, as long as the mixture solution containing the aromatic polyether contains the aromatic polyether and a first organic solvent, other components, the composition of the solution, physical properties, etc. are not particularly limited. For example, the monomer subjected to the polymerization reaction of the aromatic polyether may remain unreacted, and a reaction terminator or the like may be included.

[0030] Further, the mixture solution may be a liquid containing the aromatic polyether and the first organic solvent. In the present specification, the liquid means an aggregate system having fluidity. For example, the liquid after the polymerization reaction of the aromatic polyether may be directly used for mixing with the second organic solvent, or the solid obtained by cooling and solidifying the liquid after the polymerization reaction of the aromatic polyether may be melted and used as the mixture solution containing the aromatic polyether and the first organic solvent for mixing with the second organic solvent.

[0031] When the temperature of the mixture solution to be mixed with the second organic solvent is high, the viscosity of the mixture solution becomes low, so the dispersibility when mixed with the second organic solvent is improved, and the granulated product is easily refined. Since the viscosity of the mixture solution also depends on the composition of the mixture solution, those skilled in the art can select the temperature of the mixture solution so as to have an appropriate viscosity according to the composition of the mixture solution.

[0032] The temperature of the mixture solution to be mixed with the second organic solvent is preferably 200 ° C or higher, for example, 225 ° C or higher, 250 ° C or higher, 275 ° C or higher, or 300 ° C or higher. The upper limit of the temperature of the mixture solution to be mixed with the second organic solvent is not particularly limited as long as it is below the boiling points of the respective components contained in the mixture solution, but is, for example, 350 ° C.

[0033] If the temperature of the mixture solution is too high, there is a risk that unintended side reactions may proceed. From the viewpoint of suppressing unintended side reactions, the temperature of the mixture to be mixed with the second organic solvent is preferably a temperature near the temperature during the polymerization reaction of the aromatic polyether. For example, a temperature 20 °C higher than the temperature during the polymerization reaction of the aromatic polyether, a temperature 10 °C higher than the temperature during the polymerization reaction of the aromatic polyether, or the temperature during the polymerization reaction of the aromatic polyether can be selected as the upper limit of the temperature of the mixture.

[0034] (Aromatic polyether) The aromatic polyether contained in the mixture contains a structural unit represented by the following formula (1). [Chemical formula] [In formula (1), A contains one or more selected from the group consisting of structural units represented by the following formulas (A1) to (A3). [Chemical formula] (In formula (A1), X A1 represents -C(=O)- or -S(=O)2-. In formula (A2), X A2 and X A3 each independently represent -C(=O)- or -S(=O)2-. In formula (A3), R A represents a cyano group.) B contains one or more selected from the group consisting of structural units represented by the following formulas (B1) to (B3). [Chemical formula] (In formula (B1), R B represents a hydrogen atom or a phenyl group.) n is an integer from 0 to 2. When n is 0, the oxygen atom is directly bonded to the adjacent unit structure. When n is 1, B is directly bonded to the adjacent unit structure. When n is 2, among the two Bs, the B farthest from A is directly bonded to the adjacent unit structure.)

[0035] When there are two or more structural units represented by formulas (A1) to (A3), each of the two or more structural units represented by formulas (A1) to (A3) may be the same as or different from each other. When there are two or more structural units represented by formulas (B1) to (B3), each of the two or more structural units represented by formulas (B1) to (B3) may be the same as or different from each other.

[0036] In formulas (A1) to (A3) and (B1) to (B2), a bond across the skeleton constituting the benzene ring means a bond at a bondable position among the carbon atoms constituting the benzene ring. In formula (B3), a bond across the skeleton constituting the naphthalene ring means a bond at a bondable position among the carbon atoms constituting the naphthalene ring.

[0037] For example, formula (A1) includes all of the following structures.

Chemical formula

[0038] In one embodiment, A in formula (1) is a structure represented by formula (A1) or formula (A3). In one embodiment, X in formula (A1) A1 is -C(=O)-.

[0039] In one embodiment, A in formula (1) is a structure represented by the following formula (A1-1).

Chemical formula

[0040] In one embodiment, B in formula (1) is a structure represented by formula (B1) or formula (B2). In one embodiment, R in formula (B1) B is a hydrogen atom.

[0041] In one embodiment, the aromatic polyether contained in the mixed solution contains a structural unit represented by the following formula (1-1). [Chemical formula]

[0042] In one embodiment, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, 99.5% by mass or more, or substantially 100% by mass of the aromatic polyether is a structural unit represented by the formula (1).

[0043] In one embodiment, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, 99.5% by mass or more, or substantially 100% by mass of the aromatic polyether is a structural unit represented by the formula (1-1).

[0044] In one embodiment, in the aromatic polyether containing the structural unit represented by the formula (1), the molar ratio of the structural unit represented by A to the structural unit represented by B (structural unit represented by A:structural unit represented by B) is 47.5:52.5 to 52.5:47.5, 48.0:52.0 to 52.0:48.0, 48.5:51.5 to 51.5:48.5, 49.0:51.0 to 51.0:49.0, or 49.5:50.5 to 50.5:49.5. The number of moles of the structural unit represented by A may be larger than, smaller than, or the same as the number of moles of the structural unit represented by B.

[0045] In one embodiment, the aromatic polyether has a Cl (chlorine) atom or an F (fluorine) atom at the end of the main chain. In the aromatic polyether according to one embodiment, the structural unit represented by A is arranged at one or more ends of the main chain. In this case, the terminal structure bonded to the structural unit can be a halogen atom. The halogen atom can be, for example, a chlorine atom (Cl) or a fluorine atom (F).

[0046] In an aromatic polyether according to an embodiment, a terminal structure is bonded to a structural unit represented by B and is disposed at one or more terminals of the main chain. The terminal structure can be, for example, a hydrogen atom (H) or the like (when the terminal structure is a hydrogen atom (H), a hydroxyl group is formed together with an oxygen atom (O) in the structural unit). The terminal structure of the aromatic polyether may be, for example, a structure in which the above-described chlorine atom (Cl) or fluorine atom (F) or a hydroxyl group is replaced with a hydrogen atom (H) or the like. In addition, as the terminal structure, a structure other than those exemplified above may be provided.

[0047] The method for producing the aromatic polyether is not particularly limited. For example, it can be produced by subjecting a monomer containing a structural unit represented by A and a monomer containing a structural unit represented by B to a polymerization reaction.

[0048] Examples of the monomer containing the structural unit represented by A include halogenated diphenyl ketone, halogenated benzonitrile, halogenated diphenyl sulfone, and the like. Examples of the halogenated diphenyl ketone include 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, and the like. Examples of the halogenated benzonitrile include 2,6-difluorobenzonitrile, 2,6-dichlorobenzonitrile, and the like. Examples of the halogenated diphenyl sulfone include 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, and the like. 4,4'-Difluorobenzophenone and 4,4'-dichlorobenzophenone can be easily synthesized and are also available as commercial products.

[0049] Examples of the monomer containing the structural unit represented by B include hydroquinone, biphenol, and the like. Hydroquinone can be easily synthesized and is also available as a commercial product.

[0050] (First organic solvent) The mixture contains a first organic solvent. Examples of the first organic solvent include diphenyl sulfone, NMP, sulfolane, and the like. Since diphenyl sulfone has excellent thermal stability, it is suitably used as a solvent in the polymerization reaction of aromatic polyethers, can be easily synthesized, and is also available as a commercial product.

[0051] (Alkali metal salt) In one embodiment, the mixture contains an alkali metal salt. The alkali metal salt contained in the mixture is, for example, but not limited to, derived from the alkali metal salt remaining without being used in the de-salting polymerization reaction of aromatic polyethers.

[0052] Examples of the alkali metal salt include alkali metal carbonates, alkali metal hydrogen carbonates, and the like.

[0053] Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, and the like. Examples of the alkali metal hydrogen carbonate include lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, rubidium hydrogen carbonate, cesium hydrogen carbonate, and the like. These alkali metal salts may be used alone or in combination of two or more.

[0054] The content of the alkali metal salt in the mixture is not particularly limited.

[0055] In one embodiment, the alkali metal salt may be blended in an amount of 100 mol parts or more, or may be blended in an amount of 180 mol parts or less, 160 mol parts or less, 140 mol parts or less, or 120 mol parts or less, based on 100 mol parts of hydroquinone before the start of the polymerization reaction. If the blending amount of the alkali metal salt is 100 mol parts or more, the reaction time can be easily shortened. If the blending amount of the alkali metal salt is 180 mol parts or less, the formation of the gel component can be easily suppressed.

[0056] (Other components) The mixture may contain other components used in the polymerization reaction of the aromatic polyether. For example, solvents other than the first organic solvent, catalysts, reaction terminators, etc. may be mentioned.

[0057] (Preparation of the mixture) The mixture can be prepared, for example, by reacting a reaction mixture containing a monomer containing a structural unit represented by A, a monomer containing a structural unit represented by B, the first organic solvent, and, if necessary, an alkali metal salt and other components under predetermined conditions. In addition, if the mixture contains an aromatic polyether and the first organic solvent, the aromatic polyether is not limited to that obtained by carrying out the polymerization reaction in the mixture, and may be obtained by carrying out the polymerization reaction in another system.

[0058] The monomer containing the structural unit represented by A, the monomer containing the structural unit represented by B, the first organic solvent, the alkali metal salt, and other components are as described above.

[0059] [Second organic solvent] In the method for producing an aromatic polyether according to one aspect of the present invention, the second organic solvent is not particularly limited as long as it is a liquid in the granulation step and is a soluble organic compound for the first organic solvent. The first organic solvent and the second organic solvent may be the same or different.

[0060] By mixing the mixture containing the aromatic polyether and the first organic solvent with the second organic solvent, while simultaneously performing a part of the first organic solvent washing step and the cooling and solidifying step and the pulverizing step of the aromatic polyether, a granulated product containing the aromatic polyether can be formed. Hereinafter, the second organic solvent used in the granulation step may sometimes be referred to as the "granulation solvent".

[0061] As the second organic solvent, it is preferable to use a solvent compatible with the first organic solvent.

[0062] In this specification, the Hansen solubility parameter (HSP) is used as an index for a solvent compatible with a first organic solvent. The HSP is based on the concept that substances with similar intermolecular interactions are likely to dissolve in each other, and is composed of the following three parameters. δ d : Energy due to the dispersion force between molecules (unit: MPa 0.5 ) δ p : Energy due to the dipole-dipole interaction between molecules (unit: MPa 0.5 ) δ h : Energy due to the hydrogen bond between molecules (unit: MPa 0.5 )

[0063] In one embodiment, for the second organic solvent, at 25°C, the distance Ra of the Hansen solubility parameter defined by the following formula is 20 or less. (Ra) 2 =4(δ d2 -δ d1 ) 2 +(δ p2 -δ p1 ) 2 +(δ h2 -δ h1 ) 2 (In the formula, δ d1 , δ p1 , and δ h1 represent the HSP of the first organic solvent, and δ d2 , δ p2 , and δ h2 mean the HSP of the second organic solvent.)

[0064] For two solvents, when the distance Ra of the Hansen solubility parameter is small, it is considered that the intermolecular interactions of the respective solvents are similar, and such solvents are likely to be compatible with each other. Incidentally, although it is self-evident from the definition, in this specification, the distance Ra of the Hansen solubility parameter is in the Hansen space (δ d axis, δ p axis, and δ hIt means the distance from the first organic solvent in the three-dimensional coordinate system defined by the axis.

[0065] By using a second organic solvent with Ra of 20 or less at 25°C, a granulated product containing an aromatic polyether can be formed, and at the same time, part or almost all of the first organic solvent can be removed from the granulated product. Thereby, the aromatic polyether and the first organic solvent are separated, and it becomes easier to prevent the aromatic polyether from forming coarse solids together with the first organic solvent. Also, when mixed with a mixed solution containing an aromatic polyether and a first organic solvent, it is less likely to cause poor dispersion. When stirring is performed using rotary stirring means during mixing, it is less likely to form agglomerated lumps of the aromatic polyether on the stirring blades or the like.

[0066] The second organic solvent preferably has Ra of 15 or less at 25°C. For example, Ra is 10 or less, Ra is 7 or less, Ra is 4 or less, or Ra is 1 or less.

[0067] The lower limit value of Ra at 25°C is not particularly limited, but for example, it is 0, 0.1, 0.2, 0.3, or 0.4.

[0068] Examples of the second organic solvent with Ra of 20 or less include methanol, ethanol, 2-propanol, triethylene glycol, benzyl alcohol, methyl ethyl ketone, acetone, sulfolane (tetramethylene sulfone), cyclohexanone, 1,3-dimethylimidazolidin-2-one, cyclopentanone, N-methyl-2-pyrrolidone, thioprole (1-ethyl-1H-pyrrole-2-carbaldehyde), ethylsulfonylbenzene, 5-methylfurfural, cimetidine, N,N-dimethylbenzenesulfonamide, 5-methyltetrahydrofuran-3-one, etc., but are not limited thereto. These organic solvents may be used alone, or two or more of them may be used in combination as long as the Ra of the mixed solvent is 20 or less.

[0069] The second organic solvent is preferably soluble in water. In this specification, that the second organic solvent is soluble in water means that the second organic solvent and water are miscible. When the second organic solvent is soluble in water, when the granulated product is further washed with an acid or water for removing inorganic components, it becomes easier to remove the second organic solvent that has penetrated into the granulated product. The washing step will be described later.

[0070] Examples of the second organic solvent having Ra of 20 or less and being soluble in water include, but are not limited to, acetone, ethanol, methanol, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidin-2-one, sulfolane, etc. Among them, acetone, N-methyl-2-pyrrolidone, or 1,3-dimethylimidazolidin-2-one is preferable.

[0071] Even when a second organic solvent that is not soluble in water is used, after drying the granulated product or washing it with acetone, methanol, etc. to remove the second organic solvent that is not soluble in water, it can be subjected to the washing step described later.

[0072] When the second organic solvent is used for mixing with the mixed solution, preferably at the temperature during mixing, Ra is 10 or less, more preferably Ra is 5 or less, and still more preferably Ra is 1 or less. By reducing Ra at the mixing temperature, the dispersibility when mixing the mixed solution containing the aromatic polyether and the first organic solvent with the second organic solvent improves, and the granulated product is likely to be refined.

[0073] The temperature of the second organic solvent depends on the solvent type and the composition of the mixed solution, but those skilled in the art can select an appropriate temperature range within a range lower than the temperature of the mixed solution. If the temperature of the second organic solvent is too low, the solubility of the first organic solvent may decrease and the mixed solution may solidify quickly, and there is a risk that lumps are likely to be formed. Also, if the temperature of the second organic solvent is equal to or higher than the solidification temperature of the polymerization reactant, there is a risk that the product does not become solid and granulation cannot be performed.

[0074] The temperature of the second organic solvent is preferably 5°C or higher, for example, 10°C or higher, 15°C or higher, 20°C or higher, 25°C or higher, 30°C or higher, 35°C or higher, 40°C or higher, 45°C or higher, 50°C or higher, or 55°C or higher. When the temperature of the second organic solvent is room temperature or higher, the mixed solution does not solidify rapidly, and it becomes difficult to form lumps. As a result, it is possible to obtain granulated products without using special equipment having a high-speed rotating part such as a chopper.

[0075] Also, the temperature of the second organic solvent is preferably equal to or lower than the melting point of the aromatic polyether contained in the mixed solution, and more preferably equal to or lower than the glass transition temperature of the aromatic polyether, for example, 140°C or lower, 130°C or lower, 120°C or lower, 110°C or lower, 100°C or lower, 90°C or lower, or 80°C or lower. When the temperature of the second organic solvent is 140°C or lower, the mixed solution is less likely to swell, and granulated products are easily obtained.

[0076] The amount of the second organic solvent in the granulation step is preferably 50 parts by mass or more with respect to 100 parts by mass of the mixed solution, for example, 100 parts by mass or more, 200 parts by mass or more, or 500 parts by mass or more. The upper limit of the amount of the second organic solvent is not particularly limited, but for example, it is 5000 parts by mass or less, 2000 parts by mass or less, 1000 parts by mass or less, or 200 parts by mass or less with respect to 100 parts by mass of the mixed solution.

[0077] In the granulation step of mixing the mixed solution and the second organic solvent to obtain a granulated product in which the aromatic polyether is solidified, when adding the mixed solution to the second organic solvent, it is preferable to add the mixed solution while stirring the second organic solvent, and when adding the second organic solvent to the mixed solution, it is preferable to add the second organic solvent while stirring the mixed solution.

[0078] As the stirring conditions, stirring within an appropriate range using a general stirrer is preferable. For example, when the stirring speed is extremely slow, there is a possibility of forming lumps. A person skilled in the art can select appropriate stirring conditions.

[0079] The rate of adding the mixed solution is preferably set within an appropriate range according to the amount of the second organic solvent to be mixed and the stirring rate. For example, the mixed solution can be added at a rate of 10 g / s or less, 5 g / s or less, or 3 g / s or less per 100 mL of the second organic solvent. If the addition rate is extremely high, there is a risk of forming lumps. The lower limit of the addition rate is not particularly limited, but for example, it is 0.001 g / s. A person skilled in the art can select an appropriate addition rate.

[0080] The power required for stirring depends on the solvent type, the composition of the mixed solution and the second organic solvent. For example, it is preferably 0.01 kw / m 3 or more, for example, 0.02 kw / m 3 or more, 0.03 kw / m 3 or more, or 0.04 kw / m 3 or more.

[0081] The upper limit of the power required for stirring is not particularly limited, but for example, it is 1.0 kw / m 3 When the viscosity of the liquid obtained by mixing the mixed solution and the second organic solvent is high, or when stirring is carried out in the presence of a baffle plate, the upper limit of the power required for stirring may be 5.0 kw / m 3 as the power required for stirring.

[0082] [Grinding process] The granulated product containing the aromatic polyether obtained in the granulation process may be subjected to a grinding treatment as necessary. By performing the grinding treatment of the granulated product, the first organic solvent, inorganic components, etc. can be removed from the granulated product more efficiently in the subsequent washing process.

[0083] The method of the grinding treatment is not particularly limited, and mechanical grinding using a mill or the like may or may not be used. The granulated product containing the aromatic polyether obtained in the granulation process is easy to grind even without using mechanical grinding using a mill or the like. When mechanical grinding using a mill or the like is not used, contamination by metal elements or the like derived from the grinding equipment can be easily avoided.

[0084] The particle size after grinding is preferably 1000 μm or less, for example, 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, or 100 μm or less.

[0085] The particle size after grinding can be measured, for example, under the following measurement conditions, using a laser diffraction particle size distribution analyzer (for example, LMS-3000 manufactured by Seishin Enterprise Co., Ltd.). <Measurement conditions> Particle refractive index: 1.6 Particle absorption rate: 0.1 Wet method: ·Dispersion medium: Water ·Dispersant: Neutral detergent Dry method: ·Dispersion medium: Nitrogen ·Pressure: 0.2 MPa

[0086] As the dispersion unit, either a wet dispersion unit (for example, Hydro MV) or a dry dispersion unit (for example, Aero S) can be used. When a large amount of inorganic substances remain, it is preferable to use a dry dispersion unit. The values of the particle refractive index and the particle absorption rate under the above-described measurement conditions are common regardless of the dispersion unit.

[0087] After the granulation step, if necessary, the first organic solvent can be further removed by the washing step described below. If the first organic solvent has been sufficiently removed at the end of the granulation step, the washing step for removing the first organic solvent may not be performed. Examples of the criterion for sufficient removal of the first organic solvent include cases where the content of the first organic solvent is 300 ppm or less, 200 ppm or less, or 100 ppm or less.

[0088] The content of the first organic solvent can be measured by the method described in the examples.

[0089] [Washing process] The granulated product containing the aromatic polyether obtained in the granulation process or the pulverization process may be further washed.

[0090] When the first organic solvent derived from the mixed solution remains in the obtained granulated product, it can be washed with a solvent compatible with the first organic solvent to remove the first organic solvent. Examples of the solvent compatible with the first organic solvent include the second organic solvent (granulation solvent) described in the granulation process mentioned above.

[0091] After washing, the content of the first organic solvent in the granulated product is preferably 300 ppm or less, for example, 200 ppm or less, or 100 ppm or less.

[0092] The granulated product from which the first organic solvent has been removed can be neutralized with an acid and then washed with water to remove the remaining inorganic substances.

[0093] Examples of the inorganic substances remaining in the granulated product include alkali metal atoms contained as free components in the aromatic polyether. These inorganic substances usually originate from alkali metal salts used in the polymerization reaction and metal halides by-produced in the polymerization reaction, but are not limited thereto.

[0094] The alkali metal atoms are preferably removed so as to be 200 ppm or less, for example, 100 ppm or less, or 50 ppm or less. The content of the alkali metal atoms can be measured by the method described in the examples.

[0095] [Drying process] The granulated product containing the aromatic polyether obtained in the granulation process, the pulverization process, or the washing process can be further dried to produce an aromatic polyether powder.

[0096] As the drying means, for example, a known dryer, a thermostatic and humidistatic chamber, etc. can be used. The drying method is not particularly limited, but a vibration dryer, a hot air dryer, a vacuum dryer, a pneumatic dryer, etc. can be used.

[0097] Drying can be performed at a temperature corresponding to the type of solvent etc. remaining in the granulated product, for example, at a temperature equal to or higher than the boiling point of the remaining solvent. The drying temperature can be selected, for example, from 50 to 250 °C, 80 to 200 °C, or 100 to 180 °C etc. Also, drying can be performed under reduced pressure (vacuum drying) using a vacuum pump etc. The drying time is not particularly limited, but can be selected, for example, to be 1 minute or more, 10 minutes or more, 30 minutes or more, or 1 hour or more etc. Also, the upper limit of the drying time is not particularly limited, but can be selected, for example, to be 24 hours or less, 12 hours or less, 6 hours or less, or 3 hours or less etc.

Examples

[0098] Hereinafter, the present invention will be described more specifically with reference to examples, but the scope of the present invention is not limited to the descriptions of these examples in any way.

[0099] The Hansen solubility parameters at 25 °C of the granulation solvents used in the examples and comparative examples are shown in Table 1.

[0100]

Table 1

[0101] (Example 1) 1. Preparation of the mixture Into a 2000 mL four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a water recovery container connected to a cooling tube, 285.63 g (1.138 mol) of 4,4'-dichlorobenzophenone (manufactured by Sino-high), 123.40 g (1.121 mol) of hydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd.), 159.53 g (1.154 mol) of potassium carbonate ("FG-F20", manufactured by AGC Inc.), and 970.30 g of diphenyl sulfone (manufactured by Sino-high) were placed, and nitrogen gas was circulated.

[0102] After raising the temperature inside the reactor to 150 °C, the raw materials were dissolved at 150 °C with a stirring speed of 110 rpm. Subsequently, the stirring speed was set to 250 rpm, and the temperature was raised to 200 °C over 30 minutes, held at 200 °C for 1 hour, and then raised from 200 °C to 250 °C over 70 minutes. It was held at 250 °C for 1 hour, then the temperature was raised from 250 °C to 300 °C over 110 minutes, and further, a reaction was carried out at 300 °C for 90 minutes. Thereafter, 22.51 g (0.090 mol) of 4,4'-dichlorobenzophenone was added as a reaction terminator, held at a stirring speed of 250 rpm for 60 minutes, and the contents were taken out into a stainless steel vat and cooled and solidified at room temperature.

[0103] After completion of the reaction, the reaction product was pulverized with a blender (7010HS manufactured by Waring) to obtain a powdery reaction product. A 500 mL melting tank was filled with 200 g of the powdery reaction product and heated and melted to 300 °C or higher to prepare a mixed solution.

[0104] 2. Production of Aromatic Polyether Powder As a granulation solvent, 250 mL of cyclohexanone, which is an organic solvent, was filled into a 0.5 L separable flask, and the stirring power required was 0.03 - 0.05 kW / m with a paddle blade. 3It was heated to 70 °C while being stirred. Subsequently, about 90 g of the mixed solution was injected by nitrogen pressurization through a heating pipe from the melting tank. The time required for the injection was about 20 seconds. The granulated product was separated by filtration. The separated granulated product is shown in Fig. 1. The granulated product was weakly aggregated in the unwashed state, and when the particle size was visually confirmed using a ruler, the major axis was about 0.5 cm or less. No lumps were observed around the stirring blade.

[0105] The obtained granulated product was subjected to acetone washing, acid washing, and water washing. The washed granulated product was vacuum dried at 120 °C for 2 hours to produce an aromatic polyether powder.

[0106] 3. Washing evaluation For the produced aromatic polyether powder, the remaining diphenyl sulfone, the amount of potassium atoms, and the particle size were measured respectively.

[0107] (Measurement of the amount of residual diphenyl sulfone) Diphenyl sulfone was extracted from the granulated product into a solvent by the following pretreatment, and the diphenyl sulfone content was measured by performing GC analysis of the solvent after filtering and separating the solid matter. The results are shown in Table 2. The quantitative value was obtained based on a calibration curve prepared from a reference with a known concentration, and the calibration curve solution was made equivalent to the concentration of the sample solution. <Pretreatment conditions> About 1 g of the granulated product was collected in a 200 mL round-bottom flask with a ground stopper, 100 mL of cyclohexanone and boiling stones were added thereto, and it was heated under reflux for 1 hour with a mantle heater to extract diphenyl sulfone into cyclohexanone. Then, after allowing it to cool to room temperature, it was filtered using a polypropylene syringe filter (manufactured by GL Sciences Inc., non-aqueous system) with a pore size of 0.45 μm to remove the solid content. The obtained cyclohexanone solution was subjected to the following GC analysis. <Measurement conditions> Gas chromatograph: 8890 Gas Chromatograph (manufactured by Agilent Technologies, Inc.) Column: DB-HeavyWAX (length 30 m × film thickness 0.25 μm × inner diameter 0.25 mm) Inlet temperature: 250 °C Oven temperature: 250 °C (20 min) Flow rate: 1.0 mL / min Split ratio: 40:1 Sample injection volume: 1.0 μl Detector: FID Detector temperature: 250 °C

[0108] (Measurement of residual potassium content) The washed granulated product was dissolved under the following pretreatment conditions, and the potassium atom content was measured by ICP emission spectrometry. The quantitative value was determined based on a calibration curve prepared from a reference with a known concentration. The calibration curve solution had the same hydrochloric acid concentration as the sample solution. The results are shown in Table 2.

[0109] <Pretreatment conditions> 0.1 - 1 g of the sample was collected in a platinum dish, concentrated sulfuric acid was added thereto, and the mixture was heated for carbonization treatment. Next, it was placed in an electric furnace and subjected to ashing treatment at 550 °C for 12 hours. Hydrochloric acid was added to the sample and heated. After cooling, the volume was made constant with ultrapure water.

[0110] <Measurement conditions> · ICP emission spectrometer: 5100 manufactured by Agilent Technologies, Inc. · Measurement wavelength: 766.491 nm

[0111] (Particle size measurement) For the aromatic polyether powder, the median diameter D at which the relative particle frequency is 50% and the median diameter D at which the relative particle frequency is 90% were measured using a laser diffraction particle size distribution analyzer (LMS - 3000 manufactured by Seishin Enterprise Co., Ltd.). 50 and the median diameter D at which the relative particle frequency is 90% 90 were evaluated. For the measurement of the particle size distribution for evaluating the relative particle frequency, a wet dispersion unit (Hydro MV) was used as the dispersion unit, and the measurement was carried out under the following conditions. <Measurement conditions> · Particle refractive index: 1.6 · Particle absorption rate: 0.1 ·Dispersion medium: water ·Dispersant: neutral detergent The results are shown in Table 2.

[0112] (Example 2) A granulated product was obtained in the same manner as in Example 1, except that N-methyl-2-pyrrolidone (NMP), an organic solvent, was used as the granulation solvent. The obtained granulated product is shown in Fig. 2. The obtained granulated product was weakly aggregated in the unwashed state, and when the particle size was visually confirmed using a ruler, the major axis was about 0.5 cm or less. No lumps were observed around the stirring blade.

[0113] The obtained granulated product was subjected to acetone washing, acid washing, and water washing. The washed granulated product was vacuum dried at 120 °C for 2 hours to produce an aromatic polyether powder, and the amount of potassium atoms and the particle size were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0114] (Comparative Example 1) As the granulation solvent, 250 mL of water was filled into a 0.5 L separable flask, and granulated products were attempted in the same manner as in Example 1, except that the mixture was heated to 90 °C while stirring with a paddle blade at a required stirring power of 0.03 to 0.05 kW / m 3 2. The result was that lumps were generated around the stirring blade. The generated lumps are shown in Fig. 3. As a result, lumps were formed around the stirring blade. The formed lumps are shown in Fig. 3.

[0115] (Example 3) 1. Preparation of the mixture Into a 200 L stainless steel reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a water recovery container connected to a cooling tube, 39.00 kg (155.3 mol) of 4,4'-dichlorobenzophenone (manufactured by Sino-high), 16.85 kg (153.0 mol) of hydroquinone (manufactured by UBE Corporation), 22.20 kg (160.6 mol) of potassium carbonate (「FG-F20」, manufactured by AGC Inc.), and 132.47 kg of diphenyl sulfone (manufactured by Sino-high) were charged, and nitrogen gas was circulated.

[0116] After raising the temperature inside the reactor to 150 °C, the raw materials were dissolved at 150 °C with a stirring speed of 150 rpm. Subsequently, the temperature was raised to 200 °C over 30 minutes, held at 200 °C for 1 hour, and then raised from 200 °C to 250 °C over 70 minutes. It was held at 250 °C for 1 hour, then the temperature was raised from 250 °C to 300 °C over 150 minutes, and further, a reaction was carried out at 300 °C for 90 minutes. Thereafter, 6.15 kg (2.45 mol) of 4,4'-dichlorobenzophenone was added as a reaction terminator and held for 60 minutes to prepare a mixed solution.

[0117] 2. Production of Aromatic Polyether Powder A multifunctional filtration device (WD-50 manufactured by Nippon Steel Stainless Steel Processing Co., Ltd.) was filled with 2.7 tons of acetone, heated by a jacket to a total reflux state at a boiling point of 56 °C, and stirred at 22.5 rpm (stirring required power 0.04 kW / m 3 ) and the mixed solution was injected in a molten state through a heating pipe. After cooling, it was filtered and dried to obtain granulated powder. As a result, granulated products of 2000 μm or less were obtained. In addition, no lumps were seen in the WD filter of the filtration device.

[0118] The obtained granulated products were subjected to acetone washing, acid washing, and water washing. The washed granulated products were vacuum dried at 90 °C for 2 hours to produce aromatic polyether powder, and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0119]

Table 2

[0120] In Table 2, the granulation property was evaluated based on the following criteria for the state when the mixed solution was injected into the granulation solvent. “+”: No lumps were seen around the stirring blade. Or, no lumps were seen in the WD filter of the filtration device. “-”: Lumps were generated around the stirring blade. Or, lumps were generated in the WD filter of the filtration device.

Claims

1. A granulation step of mixing a mixed liquid containing an aromatic polyether and a first organic solvent with a second organic solvent in which the first organic solvent is soluble to obtain a granulated product in which the aromatic polyether is solidified, In the granulation step, a method for producing an aromatic polyether powder, wherein the temperature of the second organic solvent is lower than the temperature of the mixed liquid.

2. The method for producing an aromatic polyether powder according to Claim 1, wherein the distance Ra between the Hansen solubility parameter of the first organic solvent at 25°C and the Hansen solubility parameter of the second organic solvent at 25°C is 20 or less.

3. The method for producing an aromatic polyether powder according to Claim 1 or 2, wherein the first organic solvent is diphenyl sulfone.

4. The method for producing an aromatic polyether powder according to any one of Claims 1 to 3, wherein the second organic solvent is soluble in water.

5. The method for producing an aromatic polyether powder according to any one of Claims 1 to 4, wherein the temperature of the second organic solvent is 5°C to 160°C.

6. The method for producing an aromatic polyether powder according to any one of Claims 1 to 5, wherein the aromatic polyether contains a structural unit represented by the following formula (1). 【Chemical Formula 10】 [In formula (1), A includes one or more selected from the group consisting of the following formulas (A1) to (A3). 【Chemical Formula 11】 (In formula (A1), X Ａ１ represents -C(=O)- or -S(=O) ２ -. In formula (A2), X Ａ２ and X Ａ３ each independently represents -C(=O)- or -S(=O) ２ -. In formula (A3), R Ａ represents a cyano group.) B includes one or more selected from the group consisting of the following formulas (B1) to (B3). 【Chemical 12】 (In formula (B1), R Ｂ represents a hydrogen atom or a phenyl group.) n is an integer of 0 to 2. When n is 0, the oxygen atom is directly bonded to an adjacent unit structure. When n is 1, B is directly bonded to an adjacent unit structure. When n is 2, among the two Bs, the B farthest from A is directly bonded to an adjacent unit structure. ]

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