Method for producing polyphenylene ether particles

Abstract

To provide a production method in which a PPE solution can be directly dried without using a poor solvent and PPE particles having excellent handleability as a powder and a particle shape suitable for post-processing can be obtained.SOLUTION: There is provided a method for producing polyphenylene ether particles of the present invention that includes: supplying a polyphenylene ether solution containing polyphenylene ether and a good solvent for polyphenylene ether to a spray nozzle; forming droplets by discharging the solution from the spray nozzle; and removing the good solvent from the droplets to obtain polyphenylene ether particles, wherein the spray dispersibility index Dsp represented by formula (1) is adjusted to the range of formula (2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing polyphenylene ether particles. [Background technology]

[0002] Polyphenylene ether (hereinafter sometimes referred to as PPE) has excellent high-frequency characteristics, flame retardancy, and heat resistance, and is therefore widely used as a material in the electrical and electronics, automotive, and other industrial fields. While taking advantage of these properties, PPE with a lower molecular weight and increased solubility in general-purpose solvents is being investigated for use in electronic materials, as well as in composite materials and additives that can be combined with other resins to achieve superior properties.

[0003] The polymerization process used in the industrial production of PPE is either precipitation polymerization or solution polymerization. At the end of the polymerization process, precipitation polymerization results in a slurry liquid, while solution polymerization results in a solution. In the case of solution polymerization, the PPE is often mixed with a poor solvent or the like in a subsequent process to form a slurry liquid. Furthermore, PPE may be subjected to terminal modification or terminal blocking (in the present invention, terminal blocking of PPE is also considered to be modified PPE), and in such a process, it is efficient to mix PPE in a solution state, in which PPE is dissolved in a solvent, with a modifying agent, etc., and if necessary, further mix with a modifying catalyst component, and then carry out the reaction. The resulting PPE solution is often mixed with a poor solvent for PPE, etc., to form a slurry, as in solution polymerization.

[0004] The resulting PPE slurry undergoes post-processing such as washing and solid-liquid separation to obtain wet PPE. The wet PPE may then be further washed with a washing solution and the solid-liquid separation process repeated. In this case, the wet PPE contains both a good and a poor solvent for PPE. The resulting wet PPE is then dried to remove the wet components, but if the wet PPE is not washed properly, it will adhere strongly during drying, causing problems such as scaling on the heat transfer surfaces of the dryer. Furthermore, if the drying temperature is increased to improve drying efficiency, adhesion can occur within the dryer, leading to problems such as strong scaling and the detachment of scaling material, which can then be mixed into the product as foreign matter. To avoid this, multiple washing steps are required before drying, which increases the complexity and operating costs of the process. Furthermore, the filtrate separated during solid-liquid separation contains not only the good and poor solvents for PPE, but also low-molecular-weight PPE oligomer components that could not be precipitated in the poor solvent, residual catalyst components from polymerization, and end-treatment agents. Industrial production costs can be reduced by recycling the solvent components, but this requires a complex recovery process. The recovery process involves a combination of processes such as absorption, concentration, distillation, and membrane separation to separate and recover the good and poor solvents. However, because distillation is frequently used for both the good and poor solvents, a significant amount of energy is required. Furthermore, recovery of the low-molecular-weight PPE oligomer components dissolved in the good solvent is difficult, resulting in reduced PPE yield. Thus, there is a strong demand for reducing recovery costs and improving PPE yield in PPE production. Therefore, in the production of PPE, various studies have been conducted on methods for isolating PPE as a solid from a PPE solution without using a poor solvent.

[0005] Patent Document 1 describes a method for end-capping low-molecular-weight PPE, and proposes a method for isolating end-capping PPE by a process other than precipitation. One method described is direct devolatilization of the solvent, chipping, or spray drying, and a method that does not use a poor solvent. Patent Document 2 proposes a method for obtaining a dried product with a narrow particle size distribution and low dust content using a spray dryer, and discloses that a solution containing polymers, plastics, and resins as solid components in the raw material is dried using a spray dryer. Patent Document 3 proposes a micropowders containing polyarylene ether sulfones or ketones, obtained by spray drying. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2002-539278 [Patent Document 2] Japanese Patent Application Publication No. 5-57102 [Patent Document 3] Special Publication No. 8-505180 Summary of the Invention [Problem to be solved by the invention]

[0007] During the PPE manufacturing process, the properties of the PPE solution change sensitively depending on the temperature, PPE concentration, and reduced viscosity of the PPE contained. Various methods for isolating PPE by directly drying the PPE solution have been investigated, but no method has yet been developed for isolating PPE while controlling the desired particle size and shape. In particular, the method described in the above patent document, which uses a spray nozzle to turn the PPE solution into droplets and then dry them, makes it difficult to stably spray droplets of uniform size, and as a result, it is difficult to control the particle size and shape within the desired range.

[0008] The present invention has been made in consideration of the above-mentioned problems, and provides a manufacturing method that can directly dry a PPE solution without using a poor solvent, and that can produce PPE particles that are easy to handle as a powder and have a particle shape that is suitable for post-processing. [Means for solving the problem]

[0009] That is, the present invention is as follows. [1] A method for producing polyphenylene ether particles, comprising: supplying a polyphenylene ether solution containing polyphenylene ether and a good solvent for the polyphenylene ether to a spray nozzle; discharging the solution from the spray nozzle to form droplets; and removing the good solvent from the droplets to obtain polyphenylene ether particles, The spray dispersibility index D is expressed by the following formula (1) sp A method for producing polyphenylene ether particles, characterized by adjusting the content of the polyphenylene ether particles to fall within the range of the following formula (2): D sp =T / (C 2.09 ×η sp / c 1.15 ) Formula (1) (In formula (1), T is the temperature (°C) of the polyphenylene ether solution supplied to the spray nozzle, C is the concentration (mass%) of the PPE in the polyphenylene ether solution, and η sp / c represents the reduced viscosity (dL / g) of the polyphenylene ether. 0.020≦D sp ≦2.75 Formula (2) [2] The method for producing polyphenylene ether particles according to [1], wherein the polyphenylene ether solution contains a polyphenylene ether solution obtained by any one of the following methods 1) to 3): 1) A method of obtaining a polyphenylene ether liquid by bringing an oxygen-containing gas into contact with a solution containing a good solvent for polyphenylene ether, a phenolic compound, and a catalyst component to cause oxidative polymerization. 2) A method of obtaining a polyphenylene ether liquid containing a modified polyphenylene ether by mixing a modifying agent and, if necessary, a modification catalyst with a raw material liquid containing the polyphenylene ether liquid after polymerization obtained in 1) above and / or a polyphenylene ether liquid obtained by dissolving solid polyphenylene ether in a good solvent for polyphenylene ether, and causing a modification reaction. 3) A method of obtaining a polyphenylene ether liquid by dissolving solid polyphenylene ether and / or solid modified polyphenylene ether in a good solvent for polyphenylene ether. [3] The method for producing polyphenylene ether particles according to [2], further comprising a step of adjusting the polyphenylene ether concentration in the polyphenylene ether solution by further diluting the polyphenylene ether solution with a good solvent for polyphenylene ether or by concentrating the polyphenylene ether solution by removing the good solvent for polyphenylene ether from the polyphenylene ether solution. [4] The method for producing polyphenylene ether particles according to any one of [1] to [3], wherein the good solvent is volatilized and removed from the droplets by contacting the droplets with an inert gas. [5] The method for producing polyphenylene ether particles according to [4], further comprising supplying the droplets into a container, and then supplying an inert gas into the container to volatilize and remove the good solvent. [6] The method for producing polyphenylene ether particles according to [5], wherein the container has a drying function. [7] The method for producing polyphenylene ether particles according to [6], wherein the vessel having a drying function is at least one selected from the group consisting of a spray dryer, a hopper dryer, a fluidized bed dryer, a media dryer, and a flash dryer. [8] The method for producing polyphenylene ether particles according to any one of [5] to [7], wherein the pressure inside the container is set to be equal to or higher than the highest vapor pressure of the good solvent calculated by the Antoine equation at the temperature of the polyphenylene ether solution. [9] The method for producing polyphenylene ether particles according to any one of [5] to [8], wherein the container has a jacket containing a heat medium for heating the inside of the container, and the temperature of the heat medium in the jacket is set to (the boiling point of the good solvent −10)°C or higher.

[10] The method for producing polyphenylene ether particles according to any one of [4] to [9], wherein the temperature of the inert gas is set to a boiling point of the good solvent or higher.

[11] The method for producing polyphenylene ether particles according to any one of [4] to

[10] , wherein the inert gas is at least one selected from the group consisting of argon, helium, nitrogen, and carbon dioxide.

[12] The method for producing polyphenylene ether particles according to any one of [1] to

[11] , wherein the spray nozzle is at least one selected from the group consisting of a one-fluid nozzle, a two-fluid nozzle, a multi-fluid nozzle, and a disk nozzle.

[13] The method for producing polyphenylene ether particles according to any one of [1] to

[12] , wherein the good solvent is at least one selected from the group consisting of benzene, toluene, xylene, and ethylbenzene. [Effects of the Invention]

[0010] According to the present invention, it is possible to isolate PPE by directly drying a PPE solution without using a poor solvent, and to produce PPE particles that are easy to handle and have a particle shape suitable for post-processing. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0012] The method for producing polyphenylene ether particles according to the present embodiment is a method for producing polyphenylene ether particles by supplying a polyphenylene ether solution containing polyphenylene ether and a good solvent for the polyphenylene ether to a spray nozzle, discharging the solution through the spray nozzle to form droplets, and removing the good solvent from the droplets to obtain polyphenylene ether particles. sp is within the range of the following formula (2). D sp =T / (C 2.09 ×η sp / c 1.15) Equation (1) (In formula (1), T is the temperature (°C) of the polyphenylene ether solution supplied to the spray nozzle, C is the concentration (% by mass) of the polyphenylene ether solution, and η sp / c represents the reduced viscosity (dL / g) of the polyphenylene ether. 0.020≦D sp ≦2.75 Formula (2)

[0013] [PPE] The above PPE will be explained below. An example of the structure of the PPE is a homopolymer and / or copolymer having a structure represented by the following chemical formula (1), or a modified product thereof. [ka]

[0014] In the above chemical formula (1), a is an integer of 1 to 6, and n is an integer of 1 or more.

[0015] In the above chemical formula (1), R 11 , R 12 , R 13 , R 14 are each independently a hydrogen atom, a halogen atom, a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Here, the saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms and the aryl group having 6 to 12 carbon atoms may each have a substituent. R 11 , R 12 is preferably a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R 13 , R 14 is preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, a t-butyl group, a vinyl group, an aryl group, an ethynyl group, a propargyl group, or a partial structure represented by the following chemical formula (2), more preferably a hydrogen atom, a methyl group, an ethyl group, or a t-butyl group, and even more preferably a hydrogen atom, a methyl group, or a t-butyl group. 13 and R 14are not both hydrogen atoms or partial structures represented by the following chemical formula (2). [ka] (In chemical formula (2), R 21 are each independently an optionally substituted linear alkyl group having 1 to 8 carbon atoms, or two R 21 is a cyclic alkyl structure having 1 to 8 carbon atoms to which R 22 are each independently an optionally substituted alkylene group having 1 to 8 carbon atoms, each b is independently an integer of 0 or 1, and R 23 is either a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, or an optionally substituted phenyl group. The PPE represented by the above chemical formula (1) may be a homopolymer in which the n repeating units have the same structure, or a heteropolymer in which the n repeating units have a combination of different structures.

[0016] In the above chemical formula (1), A is a hydrogen atom or any substituent. Preferably, each of the substituents independently contains a carbon-carbon double bond and / or an epoxy bond. More preferably, the substituent containing a carbon-carbon double bond is a methacryl group or a vinylbenzyl group.

[0017] In the above chemical formula (1), Z is a hydrogen atom or any hydrocarbon group when a is 1. When a is 2 to 6, Z is any a-valent linking group, and preferred examples of the divalent or higher linking group include a phenol-derived structure represented by the following chemical formula (3). A single-chain homopolymer in which A and Z are hydrogen atoms is a typical PPE. [ka] In the above chemical formula (3), a can be an integer similar to that in chemical formula (1), and is preferably the same integer as that in chemical formula (1). k is an integer of 1 to 4. X is any a-valent linking group, and is not particularly limited, and examples thereof include hydrocarbon groups such as chain hydrocarbon groups and cyclic hydrocarbon groups; hydrocarbon groups containing one or more atoms selected from nitrogen, phosphorus, silicon, and oxygen; atoms such as nitrogen, phosphorus, silicon, and oxygen; or groups combining these. Preferred examples of X include hydrocarbon groups, oxygen atoms, alkylamino groups, carbonyl groups, thiocarbonyl groups, sulfinyl groups, sulfonyl groups, and groups combining these. R 31 are each independently any substituent, such as a hydrogen atom, a halogen, or a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms. Here, the saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms may have a substituent. Preferred hydrocarbon groups are one or a combination of two or more selected from alkyl groups, alkylthio groups, and alkyloxy groups. More preferred hydrocarbon groups are alkyl groups having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or an n-propyl group.

[0018] From the viewpoints of high-frequency characteristics, flame retardancy, heat resistance, and solubility in solvents, the weight-average molecular weight Mw of the PPE is preferably 500 to 200,000, more preferably 1,000 to 150,000, and even more preferably 1,500 to 100,000. When the weight-average molecular weight Mw of the PPE is 500 or more, the inherent properties of PPE, such as high-frequency characteristics, flame retardancy, and heat resistance, can be sufficiently ensured. Furthermore, when the weight-average molecular weight Mw is 200,000 or less, it can be prepared into a solution that is easy to use in the production method of this embodiment. The number-average molecular weight Mn of the PPE is not particularly limited, but is preferably in a range that allows it to be dissolved in a general-purpose solvent (e.g., toluene, dichloromethane, methyl ethyl ketone, etc.) and does not inhibit its mixability with other resins, since it is used in electronic materials, etc. Therefore, the number-average molecular weight Mn of the PPE is preferably 200 to 300,000, more preferably 500 to 250,000, and even more preferably 700 to 200,000. The molecular weight distribution Mw / Mn is preferably 1.1-5, more preferably 1.3-4, and even more preferably 1.5-3.

[0019] The weight average molecular weight Mw, number average molecular weight Mn, and molecular weight distribution Mw / Mn of the PPE can be measured using gel permeation chromatography (GPC). The weight average molecular weight (Mw) and number average molecular weight (Mn) are measured by the following methods. A gel permeation chromatography system, System 21, manufactured by Showa Denko K.K., was used as the measuring device. A calibration curve was prepared using standard polystyrene and ethylbenzene, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of the obtained PPE were measured using this calibration curve. The standard polystyrenes used had molecular weights of 3,650,000, 2,170,000, 1,090,000, 681,000, 204,000, 52,000, 30,200, 13,800, 3,360, 1,300, and 550. Two Showa Denko K-805L columns connected in series were used. Chloroform was used as the solvent, with a solvent flow rate of 1.0 mL / min and a column temperature of 40°C. A 1 g / L chloroform solution of PPE was prepared and used as the measurement sample. The UV wavelength of the detector was 254 nm for standard polystyrene and 283 nm for PPE.

[0020] The glass transition temperature (Tg) of the PPE is preferably 80°C to 300°C, and more preferably 90°C to 250°C. The glass transition temperature of the PPE can be measured using a differential scanning calorimeter, and specifically, the value is measured by the measurement method in the examples described below.

[0021] [PPE manufacturing method] Methods for producing the PPE include precipitation polymerization and solution polymerization. In both methods, phenols are oxidatively polymerized in a good solvent for PPE or in a mixed solvent of a good solvent and a poor solvent for PPE in the presence of a copper compound and amines. The phenols are not particularly limited as long as they form the repeating unit in chemical formula (1) after polymerization, and may include phenols that form the structure of chemical formula (3) after polymerization. In the precipitation polymerization method, PPE precipitates during oxidative polymerization and becomes a slurry. On the other hand, in solution polymerization, PPE does not precipitate during oxidative polymerization. Even in general solution polymerization of PPE, the PPE solution after polymerization is subjected to post-processing such as concentration if necessary, and then mixed with a poor solvent for PPE to precipitate the PPE and create a slurry. In both the precipitation polymerization method and the solution polymerization method, the resulting slurry is washed with a poor solvent or the like, subjected to solid-liquid separation, and if necessary, further washing and solid-liquid separation are repeated with a poor solvent or the like for the PPE to obtain wet PPE (washing and solid-liquid separation step).The resulting wet PPE is dried (drying step) to produce a PPE product powder.

[0022] [Denaturation of PPE] The PPE product powder is dissolved in a good solvent for PPE, and mixed with a modifier containing the A unit structure of chemical formula (1) and, if necessary, a modifying catalyst component to synthesize the modified PPE. When synthesizing PPE by solution polymerization, the modified PPE can also be synthesized by mixing a modifier containing the A unit structure of chemical formula (1) and, if necessary, a modifying catalyst component to the PPE solution after solution polymerization.

[0023] [PPE solution supplied to spray nozzle] The PPE solution supplied to the spray nozzle is a liquid containing the PPE and a good solvent for the polyphenylene ether, and preferably contains a polyphenylene ether liquid obtained by any of the following methods 1) to 3). 1) A method of obtaining a polyphenylene ether liquid by bringing an oxygen-containing gas into contact with a solution containing a good solvent for polyphenylene ether, a phenolic compound, and a catalyst component to cause oxidative polymerization. 2) A method of obtaining a polyphenylene ether liquid containing a modified polyphenylene ether by mixing a modifying agent and, if necessary, a modification catalyst with a raw material liquid containing the polyphenylene ether liquid after polymerization obtained in 1) above and / or a polyphenylene ether liquid obtained by dissolving solid polyphenylene ether in a good solvent for polyphenylene ether, and causing a modification reaction. 3) A method of obtaining a polyphenylene ether liquid by dissolving solid polyphenylene ether and / or solid modified polyphenylene ether in a good solvent for polyphenylene ether.

[0024] From the viewpoint that the PPE solution forms suitable droplets after being discharged from the spray nozzle, and particles that are easier to handle and more suitable for post-processing are obtained, it is preferable to adjust the PPE concentration in the PPE solution by adding a good solvent for the PPE to dilute it or by removing a good solvent for the PPE to concentrate it before supplying it to the spray nozzle. The PPE concentration in the PPE solution after adjusting the PPE concentration is not particularly limited as long as it is within a range in which the spray dispersibility index can be suitably adjusted, but it is preferably 5.0 to 95.0 mass% relative to 100 mass% of the PPE solution, more preferably 7.5 to 92.5 mass%, and even more preferably 10.0 to 90.0 mass%.

[0025] From the viewpoint of solubility in PPE, the good solvent for the polyphenylene ether is preferably at least one selected from the group consisting of aromatic organic solvents, ketone compounds, alcohols having 3 or more carbon atoms, chloromethane, dichloromethane, chloroform, and carbon tetrachloride, more preferably at least one selected from the group consisting of benzene, toluene, xylene, and ethylbenzene, and even more preferably toluene and / or xylene. In this specification, a "good solvent" refers to a solvent that has a solubility of 1 g or more of PPE, as measured by a method for measuring the amount of PPE dissolved in 100 g of the solvent or solvent mixture. Specifically, 100 g of the solvent or solvent mixture and 1 g of PPE were placed in a sealed container, and the liquid temperature in the sealed container was adjusted to 20±0.5°C. After leaving the container to stand for 24 hours, the presence or absence of undissolved PPE solids was visually confirmed while shaking the sealed container. If no undissolved PPE remained, the solvent was determined to be a good solvent. The mass ratio of the good solvent for polyphenylene ether relative to 100 mass% of the PPE solution is not particularly limited as long as it is within a range in which the spray dispersibility index can be suitably adjusted, but is preferably 5.0 to 99.0 mass%, more preferably 7.5 to 97.5 mass%, and even more preferably 10.0 to 90.0 mass%.

[0026] The PPE solution may consist solely of the PPE and a good solvent for the PPE, or may further contain other components, such as polymerization raw materials such as metals, metal compounds, amines, amine compounds, halogens, halogen compounds, alcohols, and ketones, and polymerization by-products such as water and quinones. The mass ratio of the other components relative to 100% by mass of the PPE solution is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0027] [Spray nozzle] In the method for producing PPE particles of this embodiment, a PPE solution is supplied to a spray nozzle, and the PPE solution is discharged to form droplets. The spray nozzle is preferably at least one selected from the group consisting of a one-fluid nozzle, a two-fluid nozzle, a multi-fluid nozzle and a disk nozzle, and more preferably a one-fluid nozzle or a two-fluid nozzle.

[0028] [Spray Dispersibility Index] In the method for producing PPE particles of this embodiment, it is important that the material discharged from the spray nozzle becomes droplets with an appropriate diameter. In order to control the droplet diameter to an appropriate value, the reduced viscosity η of the PPE contained in the PPE solution is sp / c It was found that it is important that the spray dispersibility index D (dL / g), the PPE concentration in the PPE solution: C (mass%), and the temperature of the PPE solution supplied to the spray nozzle: T (°C) have a specific relationship. sp It was found that it is important that is within a specific range. D sp =T / (C 2.09 ×η sp / c 1.15 ) Formula (1) Spray Dispersibility Index: D sp depends on the viscosity of the PPE solution. Reduced viscosity of PPE in PPE solution: η sp / c The liquid viscosity was measured when various values ​​for C (the PPE concentration in the PPE solution) and T (the temperature of the PPE solution supplied to the spray nozzle) were changed, and a relationship equation was derived by multiple regression analysis. Furthermore, based on this relationship equation, the range of the spray dispersibility index was investigated, which allows the PPE solution to be dried directly without using a poor solvent, and which provides PPE particles that are easy to handle as a powder and have a particle shape suitable for post-processing. The inventors have found that by adjusting the spray dispersibility index within the range of the following equation (2), the PPE solution can be discharged from the spray nozzle with an appropriate droplet size, the PPE solution can be dried directly without using a poor solvent, and PPE particles that are easy to handle as a powder and have a particle shape suitable for post-processing can be obtained. 0.020≦D sp ≦2.75 Formula (2) If the spray dispersibility index is less than 0.020, it becomes difficult to supply the PPE solution to the spray nozzle. Even if it is possible to supply the solution, the PPE solution discharged from the spray nozzle does not disperse into droplets but rather discharges in threads, or the PPE solution becomes tangled around the spray nozzle, making operation difficult. The dried product discharged in threads from the spray nozzle does not easily fall to the bottom of the container, but instead adheres to the inner wall or remains inside the container. Even if it does fall to the container discharge section, it can cause clogging at the discharge section. As such, a spray dispersibility index of less than 0.020 significantly reduces productivity. If the spray dispersibility index exceeds 2.75, the droplets will be dispersed too finely when sprayed out of the spray nozzle, and will not easily aggregate, so they will solidify as fine particles. If the spray dispersibility index exceeds 2.75, the dried particles will be pulverized, the dust will become explosive, and the powder will be extremely difficult to handle. The above spray dispersibility index D sp From the viewpoint of obtaining PPE particles that are easier to handle as a powder and have a particle shape that is more suitable for post-processing, the molecular weight is preferably 0.021 to 2.70, more preferably 0.022 to 2.60, and even more preferably 0.025 to 2.50. The above spray dispersibility index D sp can be adjusted, for example, by the composition of the PPE solution, the temperature of the PPE solution supplied to the spray nozzle, etc.

[0029] [Reduced viscosity of PPE] In the method for producing PPE particles of this embodiment, the reduced viscosity of the PPE contained in the PPE solution can be controlled by adjusting the molecular weight of the PPE to the above weight average molecular weight, number average molecular weight, and molecular weight distribution. The reduced viscosity of the PPE is preferably 0.025 to 0.70 dL / g, more preferably 0.050 to 0.65 dL / g, and even more preferably 0.075 to 0.60 dL / g. If the reduced viscosity is less than 0.025 dL / g, the spray dispersibility index D spThe spray dispersion index D tends to exceed 2.75, and when the droplets are ejected from the spray nozzle, they are dispersed too finely and solidify in a state where they are difficult to aggregate, which significantly deteriorates dust explosibility and powder handling. When the reduced viscosity of PPE exceeds 0.70 dL / g, the spray dispersion index D sp The dry weight tends to be less than 0.020, making it difficult to supply the dry weight to the spray nozzle, and even if it can be supplied, the dry weight is discharged in the form of threads rather than dispersed into droplets. The dried dry weight tends to adhere to the inner wall of the container and does not fall to the bottom of the container, and even if it does fall to the bottom of the container, it can cause clogging at the discharge part of the container, significantly reducing productivity. The reduced viscosity of the PPE can be adjusted to fall within the above range by appropriately setting the polymerization conditions for solution polymerization or precipitation polymerization. The reduced viscosity of the PPE can be measured by the method described in the Examples below.

[0030] [Temperature of PPE solution] In the method for producing PPE particles of this embodiment, the temperature of the PPE solution supplied to the spray nozzle is preferably 10 to 200°C, more preferably 20 to 170°C, and even more preferably 30 to 150°C. If the temperature is lower than 10°C, the spray dispersion index tends to be less than 0.020, making it difficult to supply the PPE solution to the spray nozzle. Even if the solution can be supplied, it is discharged from the spray nozzle in the form of threads rather than dispersed droplets. The dried threads tend to adhere to the inner wall of the container and are less likely to fall to the bottom of the container. Even if they do fall to the bottom of the container, they can cause clogging at the discharge section of the container, significantly reducing productivity. If the temperature exceeds 200°C, the spray dispersion index tends to exceed 2.75, causing the droplets to be excessively finely dispersed when discharged from the spray nozzle and solidifying in a state where they are difficult to aggregate, significantly worsening dust explosibility and powder handleability. The following methods can be exemplified as methods for adjusting the temperature of the PPE solution. 1) The PPE solution to be supplied to the spray nozzle is adjusted using a jacket, a heat exchanger in the circulation line, an internal temperature regulator, etc. in the tank that stores the solution. 2) Install and adjust temperature control equipment such as a heat exchanger in the piping that supplies the PPE solution to the spray nozzle. 3) Adjust by combining 1) and 2) above.

[0031] [Concentration of PPE in PPE solution] In the method for producing PPE particles according to this embodiment, the PPE concentration of the PPE solution supplied to the spray nozzle is preferably 2.0 to 90.0% by mass, more preferably 3.5 to 80% by mass, and even more preferably 5.0 to 75% by mass, relative to 100% by mass of the PPE solution. If the PPE concentration is less than 2.0% by mass, the spray dispersibility index tends to exceed 2.75, resulting in excessively finely dispersed droplets upon ejection from the spray nozzle and solidifying in a state that is difficult to aggregate, significantly deteriorating dust explosibility and powder handling. If the PPE concentration exceeds 90.0% by mass, the spray dispersibility index tends to be less than 0.020, making it difficult to supply the PPE to the spray nozzle. Even if it is possible to supply the PPE, the PPE discharged from the spray nozzle is discharged in the form of threads rather than dispersed droplets. The dried threads tend to adhere to the inner walls of the container, causing clogging at the container discharge section and significantly reducing productivity. The concentration of the PPE solution can be adjusted to the above range by using the PPE polymerization solution, a solution containing a good solvent for solid PPE, or a modified PPE solution after the PPE modification reaction as raw materials and diluting or concentrating it with a good solvent for PPE. Furthermore, when PPE is produced by solution polymerization, the concentration of the PPE solution can also be adjusted by the compounding ratio of monomers, solvents, etc.

[0032] [Liquid viscosity of PPE solution] In the method for producing PPE particles of this embodiment, the liquid viscosity of the PPE solution supplied to the spray nozzle is preferably 0.30 to 3000 cp, more preferably 0.50 to 2000 cp, and even more preferably 0.75 to 1000 cp. If the liquid viscosity is lower than 0.30 cp, the spray dispersion index tends to exceed 2.75, and the droplets are excessively finely dispersed when ejected from the spray nozzle, solidifying in a state where they are difficult to aggregate, significantly deteriorating dust explosibility and powder handleability. If the liquid viscosity exceeds 3000 cp, the spray dispersion index tends to fall below 0.020, making it difficult to supply the solution to the spray nozzle. Even if the solution can be supplied, it is discharged from the spray nozzle in the form of threads rather than dispersed droplets. The dried threads tend to adhere to the inner wall of the container and are difficult to fall to the bottom of the container. Even if they do fall to the bottom of the container, they can cause clogging at the container discharge section, significantly reducing productivity. The liquid viscosity of the PPE solution can also be adjusted to fall within the above range by appropriately setting the concentration and temperature of the PPE solution according to the reduced viscosity of the PPE.

[0033] 〔container〕 In the method for producing PPE particles of this embodiment, droplets discharged from the spray nozzle can also be supplied into a container. Examples of the container include a sealed tank, an open tank, a pipe, a container with a drying function, etc. The container may be equipped with a spray nozzle, a heating jacket, a gas supply port, a dried product discharge port, etc. Furthermore, a stirrer, a baffle, etc. may be installed inside the container.

[0034] [Container with drying function] In the method for producing PPE particles of this embodiment, it is preferable to use a container with a drying function as the container to which the PPE solution of the dried raw material is supplied from the spray nozzle. The container with a drying function is not particularly limited as long as it is an apparatus that can dry the droplets after spraying, but preferred are spray dryers, hopper dryers, fluidized bed dryers, flash dryers, media dryers, steam tube dryers, solid air dryers, inclined disk dryers, Ribocones, Nauta mixers, Henschel mixers, and high-speed mixers, and at least one selected from the group consisting of spray dryers, hopper dryers, fluidized bed dryers, media dryers, and flash dryers is more preferred, and spray dryers, hopper dryers, flash dryers, and media dryers are even more preferred. These dryers can be used in either a batch or continuous system. A jacket may be provided on the vessel (for example, a vessel having a drying function) and a heat transfer medium heated to (the boiling point of the solvent contained in the PPE solution -10)°C or higher may be supplied to the jacket. If the drying is insufficient or the particle strength is insufficient after the drying treatment in the container having a drying function, it is possible to improve the dryness and particle strength by further drying in a container having a drying function placed downstream.

[0035] [Inert gas] In the method for producing PPE particles of this embodiment, it is preferable to volatilize and remove the good solvent for the PPE from the droplets by bringing the droplets into contact with an inert gas. Alternatively, the droplets may be supplied into the container and then dried by supplying an inert gas into the container, which is preferably at least one gas selected from the group consisting of argon, helium, nitrogen, and carbon dioxide, and most preferably nitrogen, which is a commonly used gas.

[0036] In the method for producing PPE particles of this embodiment, the inert gas can be heated before supply. When the boiling point of the good solvent for PPE contained in the PPE solution is Bp and the glass transition temperature of PPE is Tg, the temperature of the inert gas after heating during supply is preferably Bp or higher, more preferably Bp to Tg°C, even more preferably (Bp + 10) to (Tg - 10)°C, even more preferably (Bp + 15) to (Tg - 20)°C, and particularly preferably (Bp + 20) to (Tg - 30)°C. If the inert gas supply temperature is lower than Bp, the drying rate is slow, requiring a long time and a large-capacity container to achieve the desired dryness. If the inert gas supply temperature exceeds Tg, the PPE may melt, causing scale formation or a change in the structure of the PPE. The above Bp may be the boiling point at the pressure inside the container.

[0037] [Container jacket temperature] When droplets are supplied to a container from a spray nozzle, a jacket can be installed inside the container and a heat transfer medium for heating the inside of the container can be supplied into the jacket. The temperature of the heat transfer medium in the jacket is preferably (Bp-10)°C or higher, more preferably (Bp-10) to (Tg-5)°C, even more preferably Bp to (Tg-15)°C, and particularly preferably (Bp+10) to (Tg-30)°C. If the temperature of the heat medium supplied to the vessel jacket is below (Bp - 10)°C, the solvent gas entrained in the inert gas condenses on the heat transfer surface, and when the condensate comes into contact with the PPE particles being dried, the PPE adheres to the heat transfer surface, slowing the drying rate. If the temperature of the heat medium supplied to the vessel jacket exceeds (Tg - 5)°C, the PPE particles containing a good solvent for PPE fuse to the heat transfer surface, slowing the drying rate. In either case, scale derived from the PPE adheres to the vessel heat transfer surface, not only reducing drying efficiency but also causing foreign matter to become mixed into the product due to scale shedding.

[0038] [Pressure inside the container] Spray dispersibility index D of PPE solution supplied to a container from a spray nozzle spIf the temperature of the PPE solution exceeds the boiling point of the good solvent in the PPE solution at normal pressure as a result of adjusting the temperature so that equation (2) is satisfied, the boiling point can be raised by pressurizing the container. This prevents the good solvent contained in the droplets discharged from the spray nozzle from bumping, which would otherwise cause the PPE to become finely divided. The pressure set in the container can be set to a value equal to or higher than the solvent vapor pressure at the set temperature calculated using a vapor pressure estimation formula such as the Antoine formula, thereby preventing pulverization due to bumping. The pressure in the container is preferably equal to or higher than the highest vapor pressure of a good solvent for the PPE calculated using the Antoine formula at the temperature of the PPE solution.

[0039] [Average particle size of PPE particles] The average particle size of the PPE particles obtained by the production method of this embodiment is preferably 5 to 3000 μm, more preferably 15 to 2000 μm, and even more preferably 20 to 1000 μm. If the average particle size is less than 5 μm, the powder becomes bulky, making it difficult to handle, and it also scatters as dust, increasing the risk of a poor working environment and dust explosions. If the average particle size exceeds 3000 μm, a long dissolution time and strong stirring are required when dissolving in a solvent and processing. The average particle size can be measured by the method described in the Examples below.

[0040] [Average sphericity of PPE particles] The average sphericity of the PPE particles obtained by the production method of this embodiment is preferably 1.0 to 3.0, more preferably 1 to 2.25, and even more preferably 1.0 to 1.75. When the sphericity is 1, the particles are completely spherical, and have excellent flowability in hoppers, feeders, etc. When the sphericity is more than 3.0, bridging may occur in the hopper, making stable discharge impossible. The average pearliness can be measured by the method described in the Examples below.

[0041] [Uniformity of particle size of PPE particles] The particle size uniformity of the PPE particles obtained by the production method of this embodiment is preferably 1.0 to 10.0, more preferably 1.0 to 7.5, even more preferably 1.0 to 5.0, and particularly preferably 1.0 to 2.5. When the particle size uniformity is 1.0, almost all of the particles have the same particle size and are not closely packed, resulting in excellent powder fluidity. When the particle size uniformity exceeds 10.0, small particles fill the voids between large particles, resulting in closely packed particles and deteriorating powder fluidity. The particle size uniformity can be measured by the method described in the Examples below.

[0042] The inventors have investigated a method for using a spray nozzle to directly dry a PPE solution after polymerization (including PPE after end-modification / end-capping) without precipitating it in a poor solvent. As a result, they have found that the desired PPE particles can be obtained stably by adjusting the reduced viscosity of the PPE in the PPE solution, the PPE concentration, and the temperature of the PPE solution supplied to the spray nozzle. This method does not require a complex process for recovering the poor solvent, and therefore eliminates the cost of recovering the poor solvent. [Example]

[0043] Hereinafter, the present embodiment will be specifically described with reference to examples and comparative examples, but the present embodiment is not limited to the following examples.

[0044] First, the methods for measuring physical properties and characteristics applied to the examples and comparative examples are shown below.

[0045] (1) Reduced viscosity (η sp / c ) measurement PPE was dissolved in chloroform to prepare a 0.5 g / dL chloroform solution. Using this chloroform solution as a sample, the reduced viscosity ηsp / c (dL / g) at 30°C was determined using an Ubbelohde viscometer.

[0046] (2) Measurement of glass transition temperature (Tg) The glass transition temperature of the PPE was measured using a differential scanning calorimeter (DSC Pyris-1, manufactured by Perkin-Elmer). In a nitrogen atmosphere, the sample was heated from room temperature to 280°C at a rate of 40°C per minute, then cooled to 50°C at a rate of 40°C per minute, and the glass transition temperature (°C) was then measured at a rate of 40°C per minute.

[0047] (3) Measurement of PPE concentration in PPE solution A W1 [g] aliquot of PPE solution was taken, the solvent components were air-dried, and the air-dried PPE mixture was placed in a vacuum dryer at a drying temperature set to between the boiling point of the contained solvent at the vacuum dryer's set pressure and (PPE glass transition temperature -5). After vacuum drying, the mixture was dried for 2 hours and the mass of the dried product was measured. If the weight of the dried product was W0 [g], the PPE concentration in the PPE solution was calculated as C = W0 / W1 × 100 [mass%]. If PPE is obtained by solution polymerization, the concentration of PPE in the PPE solution after polymerization can be calculated from the polymerization charge. Also, if solid PPE is dissolved in a good PPE solvent, the concentration of PPE in the PPE solution can be calculated from the charge at the time of dissolution. Furthermore, when the concentration of a PPE solution obtained by solution polymerization or solid PPE dissolution is adjusted by dilution or concentration, the concentration of PPE in the PPE solution can also be calculated from the mass balance during dilution or concentration. The concentration (mass %) of PPE in the resulting PPE solution can be used to calculate the spray dispersibility index.

[0048] (4) Measuring the temperature of the PPE solution supplied to the spray nozzle The temperature was measured by installing a thermometer upstream of the spray nozzle. The temperature measured below can also be used as a substitute. 1) Measure the internal temperature of the tank that stores the PPE solution to be supplied to the spray nozzle. In this case, it is preferable to keep the piping connecting the tank and the spray nozzle as short as possible, and it is desirable to use insulated piping. 2) If a heat exchanger or other device is installed in the piping that supplies the PPE solution to the spray nozzle, a thermometer should be installed near the outlet of the heat exchanger to measure the temperature. In this case, it is preferable to keep the piping connecting the heat exchanger or other device to the spray nozzle as short as possible, and it is desirable to use insulated piping. 3) A surface thermometer is installed on the pipe containing the spray nozzle to measure the surface temperature of the pipe. In this case, it is preferable to insulate the entire surface thermometer detection part with heat insulating material.

[0049] (5) Measurement of particle size and particle size uniformity The mass-average particle size of particles with a maximum particle size of 3000 μm or less was measured using a laser particle size meter (Shimadzu Corporation: SALD3100). The particle size (median diameter) at the central cumulative value of the cumulative curve of particle size distribution was taken as the average particle size. Furthermore, the particle size at 10% undersieve (D10) and the particle size at 60% undersieve (D60) were determined from the cumulative curve of particle size distribution based on the same mass, and the particle size uniformity was calculated as D60 / D10.

[0050] (6) Measurement of average sphericity The images of the PPE particles were captured using an Olympus optical microscope and then imported into a Nireco image analyzer to measure the particle's long diameter (DL) and short diameter (DS). Sphericity was calculated as DL / DS. Twenty particles having a particle size of more than 50 μm were randomly selected, and the sphericity was measured, and the arithmetic mean value of these values ​​was taken as the average sphericity.

[0051] (6) Evaluation of spray discharge stability The dispersion state of the droplets discharged from the spray nozzle and the inside of the container after operation were visually inspected and judged as follows: ◎: The PPE solution is dispersed as a mist of droplets, or there is no adhesion in the container after operation, and the product is obtained as a powder, and there is almost no adhesion of powder to the bag filter. ○1: When discharging PPE solution, most of the solution is in the form of droplets but some are in the form of threads, or dried threads adhere to the container wall, but operation can be continued. ○2: The amount of powder adhering to the bag filter is small, so there is no problem with continued operation. △1: When discharging the PPE solution, there are a lot of strings and some droplets mixed in, or the strings of dried material adhere to the container wall, making it difficult to continue operation. △2: Fine powder adheres to the bag filter, making it difficult to continue operation. ×1: Almost the entire amount of PPE solution is discharged in the form of threads, and the thread-like dried material adheres to the container wall and does not fall to the bottom of the container. ×2: Fine powder adheres to the bag filter, causing it to become clogged. XX: The PPE solution cannot be supplied to the spray nozzle, or the PPE solution gets tangled around the spray nozzle, resulting in poor supply. [Experimental equipment] A glass tube with an inner diameter of 120 mm and a length of 1000 mm was machined, and a container was created at the top end so that a separable cover could be attached, and at the bottom end so that it had a conical, sealed structure. In addition, a 30 mm diameter glass nozzle was attached to the bottom side of the glass tube so that the supplied gas could be discharged. The glass tube was fixed vertically, and the separable cover described below was attached to the top. The gas discharge nozzle was connected to the side of a glass hopper, which was cylindrical at the top and conical at the bottom, and a 2 L capacity glass tank for receiving the dried material was attached below the conical bottom of the glass hopper. The gas that flowed into the glass hopper from the gas discharge nozzle was connected to a bag filter from the top of the glass hopper, where fine powder was removed and the gas was discharged outside the system. Upper separable cover: Nozzles installed in the center and on the sides. A two-fluid spray nozzle was attached to the central nozzle. Spray nozzle: SU1A manufactured by Spraying Systems Japan Co., Ltd. Connect the PPE solution and nitrogen gas pipes to the two-fluid nozzle A gas distributor was attached to the side nozzle. Connect the heated nitrogen pipe

[0052] [Manufacturing example] A 40-liter jacketed reactor equipped with a sparger at the bottom for introducing oxygen-containing gas, stirring turbine blades and baffles, and a reflux condenser on the vent gas line at the top of the reactor was charged with 6.7 g of cupric chloride dihydrate, 24.5 g of 35% hydrochloric acid, 255.83 g of N,N,N',N'-tetramethylpropanediamine, 1.89 kg of n-butanol, 17.01 kg of methanol, and 4.8 kg of 2,6-dimethylphenol. The solvent composition (weight ratio) used was n-butanol:methanol = 10:90. Next, oxygen was introduced into the reactor via the sparger at a rate of 4.8 L / min with vigorous stirring. At the same time, a heat transfer medium was passed through the jacket to maintain the polymerization temperature at 45°C. The polymerization solution gradually took on the appearance of a slurry. 120 minutes after the start of oxygen introduction, the oxygen-containing gas aeration was stopped, and a 50% aqueous solution of 34.7 g of ethylenediaminetetraacetic acid tripotassium salt (reagent, Dojindo Laboratories) was added to the polymerization mixture. Then, 43.2 g of hydroquinone (reagent, Wako Pure Chemical Industries, Ltd.) was added in small portions. The reaction was continued at 45°C for 1 hour until the slurry PPE turned white. After the reaction was completed, the mixture was filtered and washed three times with methanol washing solution (b) in an amount such that the mass ratio (b) / (a) of the washed PPE (a) was 4. The solid-liquid mixture was centrifuged in a basket centrifuge (Tanabe Willtech Co., Ltd.) to obtain wet PPE. Centrifugation was continued until the filtrate no longer came out. The resulting wet PPE was vacuum-dried to obtain dried PPE (referred to as PPE1). The reduced viscosity η of PPE1 was 0. sp / c The molecular weight was 0.080, Mw was 2897, Mw / Mn was 1.9, and the glass transition temperature Tg was 149°C.

[0053] [Raw material PPE] The raw material PPE used was PPE1 obtained in the above production example, as well as S201A, S202A, and S203A manufactured by Asahi Kasei Plastics Singapore. The reduced viscosity and glass transition temperature of each are as follows: ·S201A η sp / c : 0.515, Tg: 211℃ ·S202A η sp / c : 0.412, Tg: 211℃ ·S203A ηsp / c : 0.321, Tg: 211℃ PPE1 η sp / c : 0.080, Tg: 149℃

[0054] [Example 1] 300 g of S203A was gradually added to 2700 g of toluene while stirring to prepare PPE Solution Example 1 with a PPE concentration of 10 mass %. Next, nitrogen heated to 140°C was supplied at 500 L / min through the gas nozzle on the upper separable cover of the experimental apparatus. Nitrogen was then supplied at 11.5 L / min through the spray nozzle, followed by PPE solution 1 at 8.0 g / min. The temperatures of the nitrogen and PPE solution 1 supplied to the spray nozzle were not specifically adjusted, and both were 30°C. The spray dispersibility index of PPE solution 1 calculated under these conditions was 0.901. After 6 hours of continuous operation, 280 g (approximately 800 mL) of PPE particles 1 were obtained. The average particle diameter was 25 μm. Droplets were discharged from the spray nozzle, with no filamentous scale or foreign matter present, and the spray discharge stability was rated as excellent. Other evaluation results are shown in Table 1.

[0055] [Comparative Example 1] A PPE solution ratio 1 was prepared in the same manner as in Example 1 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 1. The spray dispersibility index was calculated to be 4.452. After 6 hours of continuous operation, 172 g (approximately 822 mL) of PPE was obtained with a particle ratio of 1. The average particle size was 1.5 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 1.

[0056] [Example 2] The same procedure as in Example 1 was carried out, except that PPE Solution Example 2 with a PPE concentration of 60 mass % was prepared by gradually adding 1800 g of S203A to 1200 g of toluene while stirring. The spray dispersibility index was calculated to be 0.021. After 6 hours of continuous operation, 1703 g (approximately 4809 mL) of PPE particle example 2 was obtained. The average particle diameter was 102 μm. Droplets were discharged from the spray nozzle, and no thread-like scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 1.

[0057] Comparative Example 2 The same procedure as in Example 2 was carried out, except that 2100 g of S203A was gradually added to 900 g of toluene while stirring to prepare a PPE solution ratio 2 with a PPE concentration of 70 mass %. The spray dispersibility index was calculated to be 0.015. When the feed of PPE solution ratio 2 began, it was not discharged in droplets from the spray nozzle, and the PPE solution ratio 2 became entangled around the spray nozzle and solidified, making it impossible to operate. The spray discharge stability was rated XX. Other evaluation results are shown in Table 1.

[0058] [Example 3] The same procedure as in Example 1 was carried out, except that PPE Solution Example 3 with a PPE concentration of 40 mass % was prepared by gradually adding 1200 g of S201A to 1800 g of toluene while stirring. The spray dispersibility index was calculated to be 0.029. After 6 hours of continuous operation, 1104 g (approximately 3209 mL) of PPE particle sample 3 was obtained. The average particle diameter was 98 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 1.

[0059] Comparative Example 3 The same procedure as in Example 3 was carried out, except that 1500 g of S201A was gradually added to 1500 g of toluene while stirring to prepare a PPE solution ratio 3 with a PPE concentration of 50 mass %. The spray dispersibility index was calculated to be 0.018. After two hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 297 g (approximately 1288 mL), giving a PPE particle ratio of 3. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as x1. Other evaluation results are shown in Table 1.

[0060] [Example 4] PPE Solution Example 4 with a PPE concentration of 10% by mass was prepared by gradually adding 300 g of S203A to 2700 g of toluene while stirring, and the same procedure as in Example 1 was carried out except that PPE Solution 4 was heated to 50°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 1.501. After 6 hours of continuous operation, 272 g (approximately 823 mL) of PPE particle sample 4 was obtained. The average particle diameter was 32 μm. Droplets were discharged from the spray nozzle, and no thread-like scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 1.

[0061] Comparative Example 4 A PPE solution ratio 4 was prepared in the same manner as in Example 4 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 4. The spray dispersibility index was calculated to be 7.420. After 6 hours of continuous use, 156 g (approximately 818 mL) of PPE was obtained with a particle ratio of 4. The average particle size was 1.3 μm. Fine droplets were discharged from the spray nozzle, and although there was no thread-like scale or foreign matter, there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 1.

[0062] [Example 5] 2100 g of S203A was gradually added to 900 g of toluene while stirring to prepare PPE Solution Example 5 with a PPE concentration of 70 mass %. The subsequent operations were carried out in the same manner as in Example 4. The spray dispersibility index was calculated to be 0.026. After 6 hours of continuous operation, 1999 g (approximately 5760 mL) of PPE particle sample 5 was obtained. The average particle diameter was 122 μm. Droplets were discharged from the spray nozzle, and no thread-like scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 1.

[0063] Comparative Example 5 The same procedure as in Example 5 was carried out, except that 2400 g of S203A was gradually added to 600 g of toluene while stirring to prepare a PPE solution ratio 5 with a PPE concentration of 80 mass %. The spray dispersibility index was calculated to be 0.019. After 2.5 hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 897 g (approximately 4175 mL), giving a PPE particle ratio of 5. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as x1. Other evaluation results are shown in Table 1.

[0064] [Example 6] 1800 g of S201A was gradually added to 1200 g of toluene while stirring to prepare PPE Solution Example 6 with a PPE concentration of 60 mass %. The subsequent operations were carried out in the same manner as in Example 4. The spray dispersibility index was calculated to be 0.021. After 6 hours of continuous operation, 1685 g (approximately 5752 mL) of PPE particle No. 6 was obtained. The average particle diameter was 132 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was evaluated as excellent. Other evaluation results are shown in Table 1.

[0065] Comparative Example 6 The same procedure as in Example 6 was carried out, except that 2100 g of S201A was gradually added to 900 g of toluene while stirring to prepare a PPE solution ratio 6 with a PPE concentration of 70 mass %. The spray dispersibility index was calculated to be 0.015. When the feed of the PPE solution ratio 6 started, it was not discharged from the spray nozzle, and the PPE solution ratio 6 solidified inside the spray nozzle, making it impossible to operate. The spray discharge stability was evaluated as ××. Other evaluation results are shown in Table 1.

[0066] [Example 7] PPE Solution Sample 7 with a PPE concentration of 10% by mass was prepared by gradually adding 300 g of S203A to 2700 g of toluene while stirring, and the same procedure as in Example 1 was carried out except that PPE Solution Sample 7 was heated to 60°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 1.802. After 6 hours of continuous operation, 267 g (approximately 812 mL) of PPE particle No. 7 was obtained. The average particle diameter was 30 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was evaluated as excellent. Other evaluation results are shown in Table 2.

[0067] Comparative Example 7 A PPE solution ratio 7 was prepared in the same manner as in Example 7 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 7. The spray dispersibility index was calculated to be 8.904. After 6 consecutive hours, 162 g (approximately 820 mL) of PPE was obtained with a particle ratio of 7. The average particle size was 1.2 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 2.

[0068] [Example 8] 2400 g of S203A was gradually added to 600 g of toluene while stirring to prepare PPE Solution Example 8 with a PPE concentration of 80 mass %. The subsequent operations were carried out in the same manner as in Example 7. The spray dispersibility index was calculated to be 0.023. After 6 hours of continuous operation, 2224 g (approximately 7160 mL) of PPE particles 8 was obtained. The average particle diameter was 144 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 2.

[0069] [Comparative Example 8] The same procedure as in Example 8 was carried out, except that 2700 g of S203A was gradually added to 300 g of toluene while stirring to prepare a PPE solution ratio 8 with a PPE concentration of 90 mass %. The spray dispersibility index was calculated to be 0.018. After 2.1 hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 777 g (approximately 4075 mL), giving a PPE particle ratio of 8. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as x1. Other evaluation results are shown in Table 2.

[0070] [Example 9] 1800 g of S201A was gradually added to 1200 g of toluene while stirring to prepare PPE Solution Example 9 with a PPE concentration of 60 mass %. The subsequent operations were carried out in the same manner as in Example 8. The spray dispersibility index was calculated to be 0.025. After 6 hours of continuous operation, 1691 g (approximately 5779 mL) of PPE particle 9 was obtained. The average particle diameter was 138 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was evaluated as excellent. Other evaluation results are shown in Table 2.

[0071] Comparative Example 9 The same procedure as in Example 8 was carried out, except that 2100 g of S201A was gradually added to 900 g of toluene while stirring to prepare a PPE solution ratio 9 with a PPE concentration of 70 mass %. The spray dispersibility index was calculated to be 0.018. After 2.2 hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 652 g (approximately 3172 mL), giving a PPE particle ratio of 9. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as x1. Other evaluation results are shown in Table 2.

[0072] [Example 10] The same procedure as in Example 1 was carried out, except that 300 g of S203A was gradually added to 2700 g of toluene while stirring to prepare PPE Solution Sample 10 with a PPE concentration of 10 mass %, and PPE Solution Sample 10 was heated to 70°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 2.102. After 6 hours of continuous operation, 264 g (approximately 809 mL) of PPE particles 10 was obtained. The average particle diameter was 39 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 2.

[0073] [Comparative Example 10] A PPE solution ratio of 10 was prepared in the same manner as in Example 10 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 10. The spray dispersibility index was calculated to be 10.388. After 6 consecutive hours of use, 151 g (approximately 832 mL) of PPE with a particle ratio of 10 was obtained. The average particle size was 0.8 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 2.

[0074] [Example 11] 2100 g of S201A was gradually added to 900 g of toluene while stirring to prepare PPE Solution Example 11 with a PPE concentration of 70 mass %. The subsequent operations were carried out in the same manner as in Example 10. The spray dispersibility index was calculated to be 0.021. After 6 hours of continuous operation, 1996 g (approximately 6650 mL) of PPE particles 11 was obtained. The average particle diameter was 139 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 2.

[0075] [Comparative Example 11] The same procedure as in Example 11 was carried out, except that 2400 g of S201A was gradually added to 600 g of toluene while stirring to prepare a PPE solution ratio 11 having a PPE concentration of 80 mass %. The spray dispersibility index was calculated to be 0.016. When the feed of the PPE solution ratio 11 started, it was not discharged from the spray nozzle, and the PPE solution ratio 11 solidified inside the spray nozzle, making it impossible to operate. The spray discharge stability was evaluated as ××. Other evaluation results are shown in Table 2.

[0076] [Example 12] The same procedure as in Example 1 was carried out, except that 300 g of S203A was gradually added to 2700 g of toluene while stirring to prepare PPE solution sample 12 with a PPE concentration of 10 mass %, and PPE solution sample 12 was heated to 80°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 2.402. After 6 hours of continuous operation, 260 g (approximately 810 mL) of PPE particle 12 was obtained. The average particle diameter was 42 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 2.

[0077] [Comparative Example 12] A PPE solution ratio 12 was prepared in the same manner as in Example 12 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 12. The spray dispersibility index was calculated to be 11.872. After 6 consecutive hours of use, 161 g (approximately 842 mL) of PPE with a particle ratio of 12 was obtained. The average particle size was 0.9 μm. Fine droplets were discharged from the spray nozzle, and although there was no thread-like scale or foreign matter, there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 2.

[0078] [Example 13] 900 g of PPE1 was gradually added to 2100 g of toluene while stirring to prepare PPE Solution Example 13 with a PPE concentration of 30% by mass. The subsequent operations were carried out in the same manner as in Example 12. The spray dispersibility index was calculated to be 1.195. After 6 hours of continuous operation, 841 g (approximately 2550 mL) of PPE particle 13 was obtained. The average particle diameter was 87 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0079] [Comparative Example 13] The same procedure as in Example 13 was carried out, except that 600 g of PPE1 was gradually added to 2400 g of toluene while stirring to prepare a PPE solution ratio 13 with a PPE concentration of 20 mass %. The spray dispersibility index was calculated to be 2.789. After 6 consecutive hours of spraying, 376 g (approximately 1669 mL) of PPE with a particle ratio of 13 was obtained. The average particle size was 0.9 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as 02. Other evaluation results are shown in Table 3.

[0080] [Example 14] 2100 g of S201A was gradually added to 900 g of toluene while stirring to prepare PPE Solution Example 14 with a PPE concentration of 70 mass %. The subsequent operations were carried out in the same manner as in Example 12. The spray dispersibility index was calculated to be 0.024. After 6 hours of continuous operation, 1987 g (approximately 6609 mL) of PPE particles 14 was obtained. The average particle diameter was 149 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0081] [Comparative Example 14] The same procedure as in Example 14 was carried out, except that 2400 g of S201A was gradually added to 600 g of toluene while stirring to prepare a PPE solution ratio 14 with a PPE concentration of 80 mass %. The spray dispersibility index was calculated to be 0.018. After 1.8 hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 453 g (approximately 2402 mL), giving a PPE particle ratio of 14. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as x1. Other evaluation results are shown in Table 3.

[0082] [Example 15] The same procedure as in Example 1 was carried out, except that 300 g of S203A was gradually added to 2700 g of toluene while stirring to prepare PPE Solution Sample 15 with a PPE concentration of 10 mass %, and PPE Solution Sample 15 was heated to 90°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 2.702. After 6 hours of continuous operation, 257 g (approximately 808 mL) of PPE particle 15 was obtained. The average particle diameter was 37 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0083] [Comparative Example 15] A PPE solution ratio of 15 was prepared in the same manner as in Example 15 except that the PPE was changed to PPE1, and the subsequent operations were carried out in the same manner as in Example 15. The spray dispersibility index was calculated to be 13.356. After 6 consecutive hours, 149 g (approximately 802 mL) of PPE with a particle ratio of 15 was obtained. The average particle size was 0.7 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 3.

[0084] [Example 16] 900 g of PPE1 was gradually added to 2100 g of toluene while stirring to prepare PPE Solution Example 16 with a PPE concentration of 30% by mass. The subsequent operations were carried out in the same manner as in Example 15. The spray dispersibility index was calculated to be 1.344. After 6 hours of continuous operation, 846 g (approximately 2650 mL) of PPE particle 16 was obtained. The average particle diameter was 82 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0085] [Comparative Example 16] The same procedure as in Example 16 was carried out, except that 600 g of PPE1 was gradually added to 2400 g of toluene while stirring to prepare a PPE solution ratio 16 with a PPE concentration of 20% by mass. The spray dispersibility index was calculated to be 3.137. After 6 consecutive hours, 367 g (approximately 1659 mL) of PPE with a particle ratio of 16 was obtained. The average particle size was 0.8 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 3.

[0086] [Example 17] 2400 g of S201A was gradually added to 600 g of toluene while stirring to prepare PPE Solution Example 17 with a PPE concentration of 80 mass %. The subsequent operations were carried out in the same manner as in Example 15. The spray dispersibility index was calculated to be 0.0203. After 6 hours of continuous operation, 2729 g (approximately 9000 mL) of PPE particles 17 was obtained. The average particle diameter was 229 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0087] [Comparative Example 17] The same procedure as in Example 17 was carried out, except that 2700 g of S201A was gradually added to 300 g of toluene while stirring to prepare a PPE solution ratio 17 with a PPE concentration of 90% by mass. The spray dispersibility index was calculated to be 0.016. When the feed of the PPE solution ratio 17 was started, it was not discharged from the spray nozzle, and the PPE solution ratio 17 solidified inside the spray nozzle, making it impossible to operate. The spray discharge stability was evaluated as ××. Other evaluation results are shown in Table 3.

[0088] [Example 18] The same procedure as in Example 1 was carried out, except that 300 g of S202A was gradually added to 2700 g of toluene while stirring to prepare PPE solution 18 with a PPE concentration of 10 mass %, and PPE solution 18 was heated to 110°C and supplied to the spray nozzle. The spray dispersibility index was calculated to be 2.479. After 6 hours of continuous operation, 267 g (approximately 838 mL) of PPE particles 18 was obtained. The average particle size was 31 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 3.

[0089] [Comparative Example 18] A PPE solution ratio 18 was prepared in the same manner as in Example 18 except that S203A was used as the PPE, and the subsequent operations were carried out in the same manner as in Example 18. The spray dispersibility index was calculated to be 3.303. After 6 consecutive hours, 141 g (approximately 810 mL) of PPE with a particle ratio of 18 was obtained. The average particle size was 0.8 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 3.

[0090] [Example 19] 900 g of PPE1 was gradually added to 2100 g of toluene while stirring to prepare PPE Solution Example 19 with a PPE concentration of 30% by mass. The subsequent operations were carried out in the same manner as in Example 18. The spray dispersibility index was calculated to be 1.643. After 6 hours of continuous operation, 839 g (approximately 2590 mL) of PPE particles 19 was obtained. The average particle diameter was 72 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 4.

[0091] [Comparative Example 19] The same procedure as in Example 19 was carried out, except that 600 g of PPE1 was gradually added to 2400 g of toluene while stirring to prepare a PPE solution ratio 19 with a PPE concentration of 20% by mass. The spray dispersibility index was calculated to be 3.834. After 6 consecutive hours of spraying, 363 g (approximately 1759 mL) of PPE with a particle ratio of 19 was obtained. The average particle size was 0.9 μm. Fine droplets were discharged from the spray nozzle, and there was no thread-like scale or foreign matter, but there was a lot of fine powder, and the spray discharge stability was rated as △2. Other evaluation results are shown in Table 4.

[0092] [Example 20] 2400 g of S201A was gradually added to 600 g of toluene while stirring to prepare PPE Solution Example 20 with a PPE concentration of 80 mass %. The subsequent operations were carried out in the same manner as in Example 18. The spray dispersibility index was calculated to be 0.025. After 6 hours of continuous operation, 2718 g (approximately 8893 mL) of PPE particles 20 was obtained. The average particle size was 238 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was rated as Excellent. Other evaluation results are shown in Table 4.

[0093] [Comparative Example 20] The same procedure as in Example 20 was carried out, except that 2700 g of S201A was gradually added to 300 g of toluene while stirring to prepare a PPE solution ratio 20 with a PPE concentration of 90% by mass. The spray dispersibility index was calculated to be 0.019. After 2.2 hours of continuous operation, filamentous scale adhered to the wall, making it difficult to continue operation, so operation was stopped. The amount of PPE particles obtained was 553 g (approximately 3102 mL), giving a PPE particle ratio of 20. The dried product was filamentous rather than particulate, and the average particle size could not be measured. Furthermore, the product was discharged from the spray nozzle in the form of filaments, and the spray discharge stability was evaluated as ×1. Other evaluation results are shown in Table 4.

[0094] [Example 21] A PPE solution sample 21 with a PPE concentration of 90% by mass was prepared by gradually adding 2700 g of S201A to 300 g of toluene while stirring, and the PPE solution sample 21 was heated to 145°C and supplied to a spray nozzle. The same procedure as in Example 20 was carried out except that the pressure inside the experimental apparatus was increased to 0.144 MPa. The spray dispersibility index was calculated to be 0.026. After 6 hours of continuous operation, 2448 g (approximately 7406 mL) of PPE particles 21 was obtained. The average particle diameter was 298 μm. Droplets were discharged from the spray nozzle, and no filamentous scale or foreign matter was found, so the spray discharge stability was evaluated as excellent. Other evaluation results are shown in Table 4.

[0095] [Table 1]

[0096] Table 2

[0097] Table 3

[0098] Table 4

Claims

1. A method for producing polyphenylene ether particles, comprising: supplying a polyphenylene ether solution containing polyphenylene ether and a good solvent for the polyphenylene ether to a spray nozzle; discharging the solution from the spray nozzle to form droplets; and removing the good solvent from the droplets to obtain polyphenylene ether particles, The spray dispersibility index D is expressed by the following formula (1): ｓｐ A method for producing polyphenylene ether particles, characterized by adjusting the amount of the phenylene ether to fall within the range of the following formula (2): D ｓｐ =T / (C) ２．０９ ×η ｓｐ／ｃ １．１５ Equation (1) (In formula (1), T is the temperature (°C) of the polyphenylene ether solution supplied to the spray nozzle, C is the concentration (mass%) of the polyphenylene ether in the polyphenylene ether solution, and η ｓｐ／ｃ represents the reduced viscosity (dL / g) of the polyphenylene ether. 0.020≦D ｓｐ ≦2.75 Equation (2)

2. 2. The method for producing polyphenylene ether particles according to claim 1, wherein the polyphenylene ether solution contains a polyphenylene ether liquid obtained by any one of the following methods 1) to 3): 1) A method of obtaining a polyphenylene ether liquid by bringing an oxygen-containing gas into contact with a solution containing a good solvent for polyphenylene ether, a phenolic compound, and a catalyst component to cause oxidative polymerization. 2) A method of obtaining a polyphenylene ether liquid containing a modified polyphenylene ether by mixing a modifying agent and, if necessary, a modification catalyst with a raw material liquid containing the polyphenylene ether liquid after polymerization obtained in 1) above and / or a polyphenylene ether liquid obtained by dissolving solid polyphenylene ether in a good solvent for polyphenylene ether, and causing a modification reaction. 3) A method of obtaining a polyphenylene ether liquid by dissolving a solid polyphenylene ether and / or a solid modified polyphenylene ether in a good solvent for polyphenylene ether.

3. 3. The method for producing polyphenylene ether particles according to claim 2, further comprising a step of adjusting the polyphenylene ether concentration in the polyphenylene ether solution by further diluting the polyphenylene ether solution with a good solvent for polyphenylene ether or by concentrating the polyphenylene ether solution by removing the good solvent for polyphenylene ether from the polyphenylene ether solution.

4. 4. The method for producing polyphenylene ether particles according to claim 1, wherein the good solvent is volatilized and removed from the droplets by contacting the droplets with an inert gas.

5. The method for producing polyphenylene ether particles according to claim 4 , further comprising supplying the droplets into a container, and then supplying an inert gas into the container to volatilize and remove the good solvent.

6. The method for producing polyphenylene ether particles according to claim 5 , wherein the container has a drying function.

7. 7. The method for producing polyphenylene ether particles according to claim 6, wherein the vessel having a drying function is at least one selected from the group consisting of a spray dryer, a hopper dryer, a fluidized bed dryer, a media dryer, and a flash dryer.

8. The method for producing polyphenylene ether particles according to any one of claims 5 to 7, wherein the internal pressure of the container is set to be equal to or higher than the highest vapor pressure of the good solvent calculated by the Antoine equation for the temperature of the polyphenylene ether solution.

9. The method for producing polyphenylene ether particles according to any one of claims 5 to 8, wherein the container has a jacket containing a heat medium for heating the inside of the container, and the temperature of the heat medium in the jacket is set to (the boiling point of the good solvent - 10) °C or higher.

10. The method for producing polyphenylene ether particles according to any one of claims 4 to 9, wherein the temperature of the inert gas is set to a boiling point of the good solvent or higher.

11. The method for producing polyphenylene ether particles according to any one of claims 4 to 10, wherein the inert gas is at least one selected from the group consisting of argon, helium, nitrogen, and carbon dioxide.

12. The method for producing polyphenylene ether particles according to any one of claims 1 to 11, wherein the spray nozzle is at least one selected from the group consisting of a one-fluid nozzle, a two-fluid nozzle, a multi-fluid nozzle, and a disk nozzle.

13. The method for producing polyphenylene ether particles according to any one of claims 1 to 12, wherein the good solvent is at least one selected from the group consisting of benzene, toluene, xylene, and ethylbenzene.

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