Method for producing polyarylene sulfide resin and adsorption column

Abstract

The present invention provides a method for producing a polyarylene sulfide (PAS) resin, with which it is possible to perform a filtration process and a cleaning process in a short time. More specifically, the method for producing a PAS resin is characterized by including: a step (1) for reacting a polyhaloaromatic compound with an alkali metal sulfide or with an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent (a) so as to obtain a crude reaction mixture that contains at least a PAS resin, an alkali metal halide and the organic polar solvent (a); a step (2) for directly discharging the crude reaction mixture into a solution that contains an organic polar solvent (b) and a poor solvent for the PAS resin so as to bring the crude reaction mixture into contact with the solution, and subsequently removing the liquid phase component by solid-liquid separation so as to obtain a mixture (A) that contains at least the PAS resin and the alkali metal halide; and a step (3) for cleaning the mixture (A). This method for producing a PAS resin is also characterized in that: the poor solvent content in the solution used in the step (2) is 10-90 parts by mass; and the average particle diameter (D50) of the thus-obtained PAS resin is 0.5 mm or more.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polyarylene sulfide resin and an adsorption column. [Background technology]

[0002] Polyarylene sulfide (PAS) resins, typified by polyphenylene sulfide (PPS) resins, have excellent heat resistance and chemical resistance, and are widely used in electrical and electronic components, automotive parts, water heater parts, fibers, films, and other applications.

[0003] Conventional, relatively inexpensive methods for producing PAS resins include reacting a polyhalogenated aromatic compound with an alkali metal sulfide in an organic polar solvent, flushing the crude reaction mixture from a high-temperature, high-pressure state to a normal or reduced-pressure atmosphere after polymerization to remove the polymerization solvent, and then washing with water or an organic solvent to remove impurities such as inorganic salts (see, for example, Patent Documents 1 and 2). However, after the flushing process, the PAS resin becomes smaller in particle size, making it less filterable. This not only lengthens the washing and purification steps, but also increases the size of the filtration equipment, significantly affecting productivity, workability, energy costs, and other factors. To address this issue, simply increasing the particle size of the PAS resin by removing the polymerization solvent using crystallization or heated distillation, etc., results in poorer washability and end-group substitution of the PAS resin. Furthermore, the time required to remove the polymerization solvent from the crude reaction mixture, the washing time, and the amount of solvent used tend to increase, adversely affecting costs and the environmental impact. Therefore, a method for producing PAS resins that allows for rapid removal of the polymerization solvent while shortening the filtration and washing steps has been sought. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-99684 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-136629 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an object of the present invention is to provide a method for producing a PAS resin that allows the filtration and washing steps to be carried out in a short time. [Means for solving the problem]

[0006] As a result of extensive investigations, the inventors discovered that by extracting PAS resin in an aqueous solution of a mixture of an organic solvent and water after polymerization in the PAS resin production process, a PAS resin with relatively large particle size and excellent filterability can be obtained. Furthermore, because the resulting PAS resin has a large specific surface area, it exhibits washability and terminal group substitution properties equivalent to those of PAS resins with small particle size. Furthermore, they discovered that when the PAS resin obtained by this production method is used as an adsorbent, the resulting adsorption column exhibits excellent liquid permeability and, due to its large specific surface area, high adsorption capacity.

[0007] That is, the present disclosure provides a method for producing a polyhaloaromatic compound, comprising the steps of: (1) reacting a polyhaloaromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, in an organic polar solvent (a) to obtain a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and the organic polar solvent (a); a step (2) of directly discharging the crude reaction mixture into a solution containing an organic polar solvent (b) and a poor solvent for the PAS resin to bring the mixture into contact with the organic polar solvent (b) and then removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least the PAS resin and an alkali metal halide; a step (3) of washing the mixture (A) to remove the alkali metal halide; the amount of poor solvent contained in the solution containing the organic polar solvent (b) and the poor solvent for the PAS resin used in the step (2) is 10 to 90 parts by mass; The average particle diameter of the resulting PAS resin (D 50 ) is 0.5 mm or more 、relates to a method for producing a PAS resin characterized by...

[0008] Also, the present disclosure relates to a method for producing an adsorption column, which includes a step of producing a PAS resin by the method described above and a step of packing the obtained PAS resin into a column.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a method for producing a PAS resin capable of performing a filtration step and a washing step in a short time, and a method for producing an adsorption column excellent in liquid permeability and adsorption capacity packed with the PAS resin.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described in detail. However, the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. Also, when a plurality of upper limit values and lower limit values are described for specific parameters, any combination of the upper limit values and lower limit values can be used to form a suitable numerical range.

[0011] <Method for Producing PAS Resin> The method for producing a PAS resin according to this embodiment is to react a polyhaloaromatic compound with (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent (a) to obtain a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and the organic polar solvent (a) in step (1). The crude reaction mixture is directly discharged and brought into contact with a solution containing an organic polar solvent (b) and a poor solvent for the PAS resin, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least a PAS resin and an alkali metal halide in step (2). The method has step (3) of washing the mixture (A) to remove the alkali metal halide. The amount of the poor solvent contained in the solution containing the organic polar solvent (b) and the poor solvent for the PAS resin used in step (2) is 10 to 90 parts by mass. The average particle diameter of the resulting PAS resin (D 50 ) is 0.5 mm or more.

[0012] ·Process (1) Step (1) is a step of reacting a polyhaloaromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, in an organic polar solvent (a) to obtain a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and the organic polar solvent (a).

[0013] Here, in this embodiment, the polyhaloaromatic compound is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to the aromatic ring, specifically, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromonaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromodiphenylbenzene, dichlorobenzophenone, dibromobenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlorodiphenyl sulfide, dibromodiphenyl sulfide, dichlorobiphenyl, dibromobiphenyl and other dihaloaromatic compounds and their mixtures can be enumerated, and these compounds can be block copolymerized.Among these, dihalogenated benzenes are preferred, and those containing 80 mol% or more of p-dichlorobenzene are particularly preferred.

[0014] In this embodiment, an alkali metal sulfide or alkali hydrosulfide and an alkali metal hydroxide (hereinafter, sometimes referred to as a sulfidizing agent) are used as raw materials.

[0015] In this embodiment, the alkali metal sulfide includes lithium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. Such alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrides. The alkali metal sulfide can also be derived by reacting an alkali metal hydrosulfide with an alkali metal hydroxide. A small amount of alkali metal hydroxide may be added to react with the alkali metal hydrosulfide and alkali metal thiosulfate, which are usually present in trace amounts in the alkali metal sulfide.

[0016] The alkali metal hydrosulfides include lithium hydrogen sulfide, sodium hydrogen sulfide, rubidium hydrogen sulfide, cesium hydrogen sulfide, and mixtures thereof. These alkali metal hydrosulfides can be used as hydrates, aqueous mixtures, or anhydrous forms.

[0017] The alkali metal hydrosulfide is used together with an alkali metal hydroxide. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide. These may be used alone or in combination of two or more. Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred because of their easy availability, and sodium hydroxide is particularly preferred.

[0018] In the method for producing a PAS resin according to this embodiment, a hydrous sulfidizing agent can be used as a raw material. In this case, it is preferable to dehydrate the hydrous sulfidizing agent in the presence of at least an aprotic polar solvent before subjecting the agent to polymerization. Furthermore, when the amount of aprotic polar solvent charged is small, for example, less than 1 mole per mole of sulfur atoms in the sulfidizing agent, it is preferable to dehydrate the hydrous sulfidizing agent and the aprotic polar solvent in the presence of a polyhaloaromatic compound.

[0019] The dehydration step of the hydrous sulfidizing agent is carried out by charging at least an aprotic polar solvent and a hydrous alkali metal sulfide or a hydrous alkali hydrosulfide and an alkali metal hydroxide as the hydrous sulfidizing agent into a reaction vessel equipped with a distillation apparatus, heating to a temperature at which water is removed azeotropically, specifically, in the range of 300°C or less, preferably 80 to 220°C, more preferably 100 to 200°C, and discharging water by distillation to the outside of the system. In the dehydration step, dehydration is preferably carried out until the amount of water in the polymerization system is 5 moles or less, more preferably 0.01 to 2.0 moles per mole of sulfur atoms in the sulfidizing agent.

[0020] In addition, examples of the organic polar solvent (a) in this embodiment include amides, ureas, and lactams such as formamide, acetamide, N-methylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinoic acid; sulfolanes such as sulfolane and dimethylsulfolane; nitriles such as benzonitrile; ketones such as methyl phenyl ketone, and mixtures thereof. Among these, amides having an aliphatic cyclic structure, such as N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinoic acid, are preferred, and N-methyl-2-pyrrolidone is more preferred.

[0021] In the PAS polymerization step, the PAS resin polymerization reaction is carried out by reacting the alkali metal sulfide as a sulfidizing agent with a polyhaloaromatic compound in the presence of the organic polar solvent (a). Alternatively, the PAS resin polymerization reaction is carried out by reacting the alkali metal hydrosulfide and alkali metal hydroxide as sulfidizing agents with a polyhaloaromatic compound in the presence of the aprotic polar solvent. Polymerization conditions generally involve a temperature range of 200 to 330°C and a pressure range that maintains the polymerization solvent and the polyhaloaromatic compound (polymerizable monomer) substantially in liquid phase, generally selected from the range of 0.1 to 20 MPa, preferably 0.1 to 2 MPa. The amount of polyhaloaromatic compound charged is adjusted to 0.2 to 5.0 moles, preferably 0.8 to 1.3 moles, and more preferably 0.9 to 1.1 moles per mole of sulfur atom in the sulfidizing agent. The amount of aprotic polar solvent used is adjusted to 1.0 to 6.0 moles, preferably 2.5 to 4.5 moles, per mole of sulfur atom in the sulfidizing agent. The polymerization reaction is preferably carried out in the presence of a small amount of water, the proportion of which is preferably adjusted appropriately depending on the polymerization method, the molecular weight of the resulting polymer, and productivity. Specifically, the dehydration operation is carried out so that the amount of water is 2.0 moles or less, preferably 1.6 moles or less, per mole of sulfur atom in the sulfidizing agent. Furthermore, when the dehydration operation is carried out in the presence of a polyhaloaromatic compound (for example, the method "5") in the specific embodiment below), the amount of water is 0.9 moles or less, preferably 0.05 to 0.3 moles, more preferably 0.01 to 0.02 moles.

[0022] Specific embodiments of polymerizing a sulfidizing agent and a polyhaloaromatic compound in the presence of the organic polar solvent (a) include, for example, 1) A method using a polymerization aid such as an alkali metal carboxylate or a lithium halide, 2) A method using a branching agent such as an aromatic polyhalogen compound, 3) A method in which the polymerization reaction is carried out in the presence of a small amount of water, and then water is added to carry out further polymerization. 4) A method in which the gas phase portion of the reaction vessel is cooled during the reaction of the alkali metal sulfide with the aromatic dihalogen compound, and a part of the gas phase in the reaction vessel is condensed and refluxed to the liquid phase; 5) A method for producing a PAS resin, the essential steps of which include a step of reacting an alkali metal sulfide, or a hydrous alkali metal hydrosulfide and an alkali metal hydroxide, with an amide, urea, or lactam having an aliphatic cyclic structure in the presence of a polyhalo-aromatic compound while dehydrating to produce a slurry containing a solid alkali metal sulfide; a step of adding a polar organic solvent such as NMP after producing the slurry and distilling off the water to dehydrate it; and a step of reacting the polyhalo-aromatic compound, the alkali metal hydrosulfide, and the alkali metal salt of a hydrolyzate of the amide, urea, or lactam having an aliphatic cyclic structure in the slurry obtained through the dehydration step, at a concentration of 0.02 mol or less of water present in the reaction system per 1 mol of polar organic solvent such as NMP, to polymerize the slurry.

[0023] In this way, the polymerization reaction of a dihaloaromatic compound with (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent (a) produces a PAS resin as a product, but also produces cyclic PAS oligomers as a by-product. Other substances remaining after the reaction may include by-products such as alkali metal-containing inorganic salts, carboxyalkylamino group-containing compounds, and terminal SH group-containing compounds, as well as unreacted raw materials and water. In particular, the inclusion of an alkali metal halide as an essential component in the crude reaction mixture is believed to contribute to an increase in the specific surface area of ​​the resulting PAS resin. Specifically, the alkali metal halide is incorporated into the PAS resin during its aggregation in the poor solvent in step (2), and then released by washing in step (3), resulting in porosity.

[0024] ·Process (2) Step (2) is a step in which the crude reaction mixture is directly discharged into a solution containing an organic polar solvent (b) and a poor solvent for the PAS resin, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least the PAS resin and an alkali metal halide.

[0025] In this step, the method for directly discharging the crude reaction mixture obtained in step (1) into a solution containing an organic polar solvent (b) and a poor solvent for the PAS resin (hereinafter simply referred to as the "mixed solution") is not particularly limited, as long as it does not impair the effects of the present invention. For example, the crude reaction mixture may be transported through a pipe to a vessel containing the mixed solution and then discharged from a pipe installed at a position lower than the liquid level of the mixed solution. By using this method of discharging into the mixed solution, flash cooling of the crude reaction mixture can be prevented, even when the crude reaction mixture is transported at high temperature and pressure, and a PAS resin with a large particle size can be obtained.

[0026] The organic polar solvent (b) used in this step may be the same as the organic polar solvent (a) described above. Examples of poor solvents for PAS resin include water, acetone, dimethyl sulfoxide, tetrahydrofuran, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol, alcohols with 3 or less carbon atoms, such as 2-methoxyethyl alcohol, alcohols with ether bonds and 3 or less carbon atoms, alcohols with ketone groups and 3 or less carbon atoms, and alcohols with ester groups and 3 or less carbon atoms. Among these, water or alcohol is preferred.

[0027] The mixed solution used in this step comprises the organic polar solvent (b) and the poor solvent. The amount of the poor solvent contained in the mixed solution (poor solvent content) is 10 to 90 parts by mass, preferably 20 to 80 parts by mass. By using such a mixed solution, the PAS resin can be efficiently aggregated when it comes into contact with the crude reaction mixture, thereby producing a PAS resin with a large particle size.

[0028] The amount of the mixed solution used in this step is preferably in the range of 100 to 10,000 parts by mass per 100 parts by mass of the PAS resin (theoretical yield) contained in the crude reaction mixture from the viewpoint of particle size control, more preferably 200 to 5,000 parts by mass, and even more preferably 400 to 2,000 parts by mass. The temperature of the mixed solution is not particularly limited as long as the mixed solution is in a liquid state, but is preferably -10 to 220°C, more preferably 10 to 150°C, and even more preferably 30 to 90°C from the viewpoint of utility reduction. The pressure of the mixed solution is not particularly limited and can be set at any pressure as long as the mixed solution is in a liquid state and is equal to or lower than the pressure during the polymerization reaction in step (1). For example, it can be set in the range of 5 kPa to 1.9 MPa (gauge pressure), preferably 50 kPa to 0.9 MPa (gauge pressure), and more preferably 101.3 kPa to 0.4 MPa (gauge pressure).

[0029] The method for removing the liquid phase component by solid-liquid separation in this step is not particularly limited as long as it does not impair the effects of the present invention, and known devices and methods can be used. For example, an appropriate method can be selected from vacuum distillation, centrifugation, screw decanter, vacuum filtration, pressure filtration, etc. These methods can also be combined or repeated.

[0030] ·Process (3) Step (3) is a step of washing the mixture (A) to remove the alkali metal halide.

[0031] In this step, the mixture (A) is washed with water and / or hot water. Examples of methods for solid-liquid separation after water washing include a method of adding water to the slurry, stirring the mixture, and then filtering it using a filtration device, a method of adding water again to the moisture-containing filter residue obtained by the filtration (hereinafter abbreviated as "wet cake") to form a slurry, and then filtering the slurry, and a method of adding water again to the wet cake retained in the filter, and then filtering the slurry.

[0032] In terms of washing efficiency, the amount of water added to the mixture (A) during the water washing is preferably in the range of 2 to 20 times the theoretical yield of the final PAS resin, and the above amount of water is preferably divided into 1 to 10, preferably 1 to 4, washing steps. The water washing is preferably carried out in a nitrogen or air atmosphere at a water temperature in the range of 20 to 300°C. In terms of improving washing efficiency, it is more preferable to carry out the water washing in the range of 50 to 100°C, and most preferably in the range of 70 to 90°C. The water washing can be carried out once or multiple times. When water washing is carried out multiple times, the atmospheric and temperature conditions may be the same or different.

[0033] The filtered solid phase component may contain trace amounts of alkali metal halide or sulfidizing agent that have not been washed off completely, so it is preferable to further contact the solid phase component with water in the range of 100°C to 280°C and then perform solid-liquid separation (hereinafter sometimes referred to as "hot water washing").

[0034] The temperature for hot water washing is preferably, for example, in the range of 100°C to 280°C, and more preferably in the range of 120°C to 275°C, from the viewpoint of improving the extraction efficiency of alkali metal halides and sulfidizing agents remaining in the resin. More specifically, it is preferable to carry out the extraction treatment with hot water at 140°C to 260°C under increased pressure in the gas phase in the reactor, more preferably under conditions of 0.2 to 4.6 MPa (gauge pressure).

[0035] A specific method for performing such hot water washing includes washing the solid phase component filtered out after the water washing with agitation in a pressure vessel under predetermined pressure and temperature conditions. The amount of water used during hot water washing is preferably 1.5 to 10 times the mass of the PAS resin, from the viewpoint of improving the extraction efficiency of the alkali metal halide. This amount of hot water may be divided into two or more separate hot water washes. For example, when hot water washing is repeated twice, it is preferable to perform filtration between the first and second hot water washes to filter out the alkali metal halide extracted in the first hot water wash and the PAS resin. Alternatively, filtration may be performed after one hot water wash, followed by the aforementioned water washing. This procedure can also further promote the separation and removal of the alkali metal halide from the PAS resin. Although the conditions for the first and second hot water washing steps can be selected arbitrarily from the above conditions, it is preferable to set the temperature for the first hot water washing step to, for example, a temperature in the range of 120°C to 250°C, and after first filtering and removing the highly alkaline filtrate, to carry out the second hot water washing step at a temperature higher than that of the first hot water washing step, for example, a temperature in the range of 150°C to 275°C, from the viewpoint of the chemical resistance of the equipment used in the hot water washing. In this step, hot water washing and solid-liquid separation can also be repeated.

[0036] In this step, a water washing tank having an agitator and a centrifuge for solid-liquid separation can be used, but it can also be performed in a vessel with a mixing function that has an internal agitator and a filtration filter at the bottom. Even for hot water washing at temperatures above 100°C, a water washing tank having an agitator for hot water washing and a centrifuge for subsequent filtration at 20 to 100°C can be used, but it can also be performed in a sealed or sealable vessel with a mixing function that has an internal agitator and a filtration filter at the bottom. In this embodiment, water washing or hot water washing may be performed continuously or batchwise.

[0037] The solid phase component containing the PAS resin obtained through the above steps (1) to (3) may then be dried as is and used as a PAS resin powder, or it may be further washed, subjected to solid-liquid separation, and dried to prepare a powdered or granular PAS resin.

[0038] The PAS resin obtained by the production method according to this embodiment has an average particle diameter (D 50 ) is preferably 0.5 mm or more, more preferably 0.6 mm or more, and even more preferably 0.7 mm or more. 10 ) is preferably 0.10 mm or more, more preferably 0.15 mm or more, and even more preferably 0.20 mm or more. Within this range, the PAS resin has excellent filterability, and the filtration step after solid-liquid separation from the polymerization solvent and the washing step can be carried out in a short time. The particle size distribution in this disclosure is measured in accordance with a conventional method using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300EXII), and is the average particle size (D) at 50% of the cumulative particle size distribution curve. 50 ) and the average particle size at 10% of the cumulative particle size distribution curve (D 10 )

[0039] The PAS resin obtained by the manufacturing method according to this embodiment has a loose bulk density of 250 kg / m 3 less than 200 kg / m 3 It is preferable that the saturation is 150 kg / m or less. 3 It is more preferable that the compacted bulk density is 350 kg / m or less. 3 It is preferable that the saturation is 300 kg / m or less. 3 More preferably, it is 250 kg / m or less. 3It is more preferable that the ratio of the packed bulk density to the difference between the loose bulk density and the packed bulk density (compressibility) is 1 to 35%, more preferably 5 to 30%, and even more preferably 15 to 25%. Within this range, the PAS resin exhibits excellent filterability, and also excellent mixability and flowability when used as a raw material for resin compositions and molded articles. The loose bulk density, packed bulk density, and compressibility in this disclosure are values ​​measured using the methods in the Examples.

[0040] The alkali metal content of the PAS resin obtained by the production method according to this embodiment is preferably 500 ppm or less, more preferably 450 ppm or less, and even more preferably 400 ppm or less. By keeping the alkali metal content within this range, the crystallization rate of the resulting PAS resin increases, resulting in excellent processability. The alkali metal content of the PAS resin in this disclosure is a value measured by the method in the Examples.

[0041] The PAS resin obtained by the manufacturing method according to this embodiment has a BET specific surface area of ​​10 m 2 / g or more, and 15m 2 / g or more is more preferable, and 20m 2 / g or more is even more preferable. In this range, the cleaning efficiency and the terminal group substitution efficiency during the purification of PAS resin are excellent. Furthermore, when the PAS resin is used as an adsorbent, the adsorption performance is excellent. The BET specific surface area in this disclosure is the BET specific surface area measured using a Shimadzu Tristar II3020 after pretreating the PAS resin particles under vacuum at 60°C for 4 hours.

[0042] <Method of manufacturing an adsorption column> The method for producing an adsorption column according to this embodiment includes the steps of producing a PAS resin by the above-described method and packing the resulting PAS resin into a column. The PAS resin obtained by this method has excellent filterability, and therefore excellent liquid permeability when packed into a column or the like as an adsorbent. This allows for a high solution processing rate. Furthermore, the PAS resin obtained by this method has a large specific surface area, resulting in a large contact area with the solution and excellent adsorption capacity.

[0043] The shape and material of the column are not limited, and known and commonly used materials can be used. Furthermore, in this embodiment, the method for packing the PAS resin into the column is not particularly limited, and known methods can be used. For example, the PAS resin is dispersed in an appropriate liquid medium, such as water, to form a slurry, and then the slurry is packed into a column of a certain volume. A solvent is then introduced by gas pressure or pump pressure to compact the PAS resin. When the PAS resin obtained by the above-described manufacturing method is packed into a column, the loose bulk density may vary depending on the packing conditions, but it is believed that the surfaces (interfaces) of the resin particles will not fuse together. Therefore, the contact area with the solution is large, resulting in excellent adsorption capacity. When the PAS resin is packed into the column, a known and commonly used filter aid may also be packed.

[0044] When the PAS resin obtained by the manufacturing method according to this embodiment is used as an adsorbent, it is preferable that the PAS resin does not contain any external additives (components present outside the PAS resin, mainly components present at the interface between the PAS resin and a liquid) or internal additives (components present inside the PAS resin as a result of melt-kneading or the like) other than the PAS porous body (excluding unavoidable components derived from the PAS polymerization reaction and water), such as known and commonly used additives such as surfactants (dispersants), colorants, antistatic agents, antioxidants, heat stabilizers, UV stabilizers, UV absorbers, foaming agents, flame retardants, flame retardant assistants, rust inhibitors, release agents, and coupling agents.

[0045] The PAS resin obtained by the production method of this embodiment can be used for purposes other than adsorbents. For example, like conventional PAS resins, it can be blended with fillers and other resins and melt-kneaded, then molded directly or after first being pelletized, into molded articles with excellent heat resistance, moldability, dimensional stability, and other properties by various melt processing methods such as injection molding, extrusion molding, compression molding, and blow molding. However, to further improve performance such as mechanical strength and dimensional stability, it can also be used in combination with various fillers within the scope of the present invention. Examples of fillers include fibrous fillers and inorganic fillers. Furthermore, during molding, small amounts of mold release agents, colorants, heat stabilizers, UV stabilizers, foaming agents, rust inhibitors, flame retardants, lubricants, and coupling agents can be added as additives within the scope of the present invention. Furthermore, the following synthetic resins and elastomers can also be mixed and used. Examples of these synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylate, polyethylene, polypropylene, polytetrafluoroethylene, polydifluoroethylene, polystyrene, ABS resin, epoxy resin, silicone resin, phenolic resin, urethane resin, and liquid crystal polymer. Examples of the elastomer include polyolefin rubber, fluorine rubber, and silicone rubber.

[0046] Furthermore, the PAS resin obtained by the production method according to this embodiment is similar to conventional PAS resins in terms of excellent chemical resistance, heat resistance, moldability, dimensional stability, etc. Therefore, it can be widely used, for example, in electrical and electronic components such as connectors, printed circuit boards, and encapsulated molded products, automotive components such as lamp reflectors and various electrical components, interior materials for various buildings, aircraft, and automobiles, injection-molded and compression-molded products such as precision parts for office equipment, camera parts, and watch parts, and extrusion-molded and pultrusion-molded products such as fibers, films, sheets, and pipes. [Example]

[0047] The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting. Unless otherwise specified, "%" and "parts" are based on mass.

[0048] <Evaluation>

[0049] (1) Evaluation of loose bulk density, compacted bulk density, and compressibility The bulk density and compressibility of each PPS resin obtained in each example and comparative example were measured using a Powder Tester (registered trademark) PT-X manufactured by Hosokawa Micron Corp. in the following manner. The results are shown in Tables 1 and 2.

[0050] (Loose bulk density) PPS resin was poured into a 100 mL stainless steel cylindrical container (inner diameter 50.46 mm x depth 50 mm) with a bottom using a medicine spoon until it overflowed, and after the PPS resin was leveled off, the weight was measured to the nearest 0.01 g. The number average of three measurements of the weight was divided by the internal volume of the cylindrical container with a bottom to obtain the loose bulk density (kg / m 3 ) was calculated as

[0051] (hard bulk density) A resin adapter (internal diameter 50.46 mm x length 40 mm) of sufficient capacity was tightly attached to the top of a bottomed cylindrical container similar to that used for measuring the loose bulk density, and PPS resin was poured into it until it overflowed using the same procedure as for measuring the loose bulk density. After that, with the adapter still attached, the bottomed cylindrical container was subjected to vibrations of 1.5 mm amplitude and 50 Hz for 30 seconds using a motor with an eccentric weight attached to the rotating shaft. Next, the adapter was removed, and the PPS resin was drained to the level, after which the weight was measured to the nearest 0.01 g. The number average of three measurements of this weight was divided by the internal volume of the bottomed cylindrical container to determine the packed bulk density (kg / m 3 ) was calculated as

[0052] (Compression degree) The degree of compressibility (%) was calculated from the above values ​​of the firm bulk density and the loose bulk density according to the following formula. Compressibility (%) = {Bulk density (kg / m 3 ) - Loose bulk density (kg / m 3)} / solid bulk density (kg / m 3 )

[0053] (2) Measurement of alkali metal content The PPS resin obtained in each example and comparative example was weighed into a platinum crucible, and concentrated sulfuric acid (atomic absorption grade) was added to cover the resin. The resin was then completely ashed using a microwave ashing device manufactured by Milestone General Co., Ltd. 1% hydrochloric acid and pure water were added to dissolve the ash, and the resulting solution was analyzed for sodium content using an atomic absorption spectrophotometer. The sodium content in the PPS was quantified from the value obtained. The pure water used had a conductivity of 18.2 MΩ·cm. The results are shown in Tables 1 and 2.

[0054] (3) Measurement of specific surface area The specific surface area was measured using a Shimadzu Tristar II3020. The PPS resin obtained in each example and comparative example was pretreated by standing at 60°C under vacuum for 4 hours, then placed in a measurement cell, degassed, and purged with helium. The resin was then cooled to -196°C and purged with nitrogen to measure the specific surface area. The results are shown in Tables 1 and 2.

[0055] (4) Evaluation of filterability 600 g of 70°C ion-exchanged water was added to 100 g of the crude PPS mixture obtained through steps (1) and (2), and the mixture was stirred for 30 minutes. The mixture was then fed into a Buchner funnel equipped with filter paper (Qualitative Filter Paper No. 1, 125 mmφ, manufactured by ADVANTEC) and subjected to suction filtration (vacuum pressure 40.0 kPa). The time required for filtration was recorded as the filtration time. The results are shown in Table 1. 1 L of 70°C ion-exchanged water was then added to the filtered cake, and the mixture was subjected to suction filtration (vacuum pressure 40.0 kPa). The times required for filtration are shown in Tables 1 and 2. Resins that require a shorter filtration time have better filterability.

[0056] (5) Evaluation of particle size distribution (D 50 , D 10 ) The particle size distribution of the PPS resin obtained in each example and comparative example was measured using a laser diffraction scattering particle size distribution analyzer (Microtrac MT3300EXII) in accordance with the laser diffraction and scattering method (JIS Z8825). 50 and D 10 The results are shown in Tables 1 and 2.

[0057] (6) Evaluation of liquid permeability 8.0 g of the undried PPS resin obtained in each Example and Comparative Example was packed into a glass cylindrical column with an inner diameter of 9 mm and a height of 100 mm, and water was passed through the column at a flow rate adjusted to SV = 100. The pump discharge pressure (pressure in the liquid passage line) was measured six times every 5 minutes using a pressure gauge installed in front of the column, and the average value was calculated. The pump discharge pressure (Pa) is represented as "○" if less than 1, "△" if 1 to 10, and "×" if 10 or more.

[0058] (7) Evaluation of adsorption The undried PPS resin obtained in each Example and Comparative Example was placed in a test tube so that the PPS resin was 0.005 g, and 5.0 mL of palladium solution was added. This was shaken horizontally at 200 rpm for 3 hours using a shaker (Yamato Scientific Co., Ltd., "SA300") at 30°C. The liquid phase component and PPS resin were then recovered by filtration. The palladium concentration in the liquid phase component was quantified using an atomic absorption spectrophotometer, and the adsorption rate (%) was calculated using the solution concentration before adsorption (C0) and the solution concentration after adsorption (C). A value of 60% or more was indicated by "◎", a value of less than 60% but 30% or more was indicated by "◯", a value of less than 30% but 10% or more was indicated by "△", and a value of less than 10% was indicated by "×". Adsorption rate (%)=(C0-C) / C0×100

[0059] Example 1 ·Process (1) A 1-L autoclave equipped with a stirring blade and connected to a pressure gauge, thermometer, condenser, decanter, and rectification column was charged with 244.02 g (1.66 mol) of DCB, 26.96 g (0.16 mol) of NMP, 201.78 g of 47.23 wt% NaSH aqueous solution (1.70 mol as NaSH), and 135.74 g of 49.21 wt% NaOH aqueous solution (1.67 mol as NaOH). The mixture was heated to 173 °C over 5 hours under a nitrogen atmosphere with stirring, distilling off 200.59 g of water, and then the kettle was sealed. The DCB distilled azeotropically during dehydration was separated in the decanter and returned to the kettle as needed. After dehydration, the anhydrous sodium sulfide composition was dispersed in the DCB. After the dehydration step was completed, the internal temperature was cooled to 160°C, and 340.92 g (3.40 mol) of NMP was charged and heated to 185°C. When the pressure reached 0.00 MPa, the valve connected to the distillation column was opened, and the internal temperature was raised to 200°C over 1 hour. During this time, the cooling and valve opening were controlled so that the temperature at the outlet of the distillation column remained below 110°C. The distilled mixed vapor of DCB and water was condensed in a condenser and separated in a decanter, and the DCB was returned to the kettle. The amount of distilled water was 1.32 g. The internal temperature was raised from 200°C to 230°C over 3 hours, stirred for 3 hours, and then raised to 250°C and stirred for 1 hour.

[0060] ·Process (2) The crude reaction mixture obtained in step (1) was poured into 1 L of a mixed solution (10 wt% water, 90 wt% NMP) kept at 40°C under atmospheric pressure over 85 seconds to obtain a mixture. The entire mixture obtained was filtered, and the NMP was removed under vacuum in a 2 L vacuum agitator dryer equipped with an agitator blade at 150°C for 4 hours, after which the mixture was cooled to room temperature. A crude PPS mixture with a solids concentration of 99.5% was obtained.

[0061] ·Process (3) 100 g of the resulting crude PPS mixture was mixed with 600 g of 70°C ion-exchanged water, stirred for 30 minutes, and then filtered. 1 L of 70°C ion-exchanged water was added to the filtered cake for cake washing. The resulting wet cake and 600 g of ion-exchanged water were then placed in a 1-L autoclave equipped with a stirring blade, heated to 230°C over 2 hours with stirring, stirred for 30 minutes for extraction, and cooled to room temperature. The entire mixture was filtered, and 1 L of 70°C ion-exchanged water was added to the filtered cake for cake washing. The cake was then dried at 120°C for 4 hours to obtain a PAS resin. The properties of the resulting PPS resin are shown in Table 1.

[0062] <Example 2> ·Process (1) The same procedure as in Example 1 was carried out.

[0063] ·Process (2) The composition obtained in step (1) was poured into 1 L of a mixed solution (10 wt % water, 90 wt % NMP) kept at 40°C under atmospheric pressure over 85 seconds to obtain a crude PPS mixture. The entire crude PPS mixture obtained was filtered to obtain a crude PPS mixture with a solids concentration of 25%.

[0064] ·Process (3) To 100 g of the resulting crude PPS mixture, 600 g of 70°C ion-exchanged water was added, stirred for 30 minutes, and then filtered. 1 L of 70°C ion-exchanged water was added to the filtered cake for cake washing. This procedure was repeated three times. 600 g of 25°C ion-exchanged water was then added, and acetic acid was added until the pH reached 4. After stirring for 30 minutes, the mixture was filtered. 1 L of 25°C ion-exchanged water was added to the filtered cake for cake washing. Another 600 g of 25°C ion-exchanged water was added, stirred for 30 minutes, and then filtered. 1 L of 25°C ion-exchanged water was added to the filtered cake for cake washing. The mixture was then dried at 120°C for 4 hours. The properties of the resulting PPS resin are shown in Table 1.

[0065] Example 3 The procedure of Example 1 was repeated except that the resin was removed in step (2) as follows. The properties of the resulting PPS resin are shown in Table 1. The composition obtained in step (1) was poured into 1 L of a mixed solution (90 wt % water, 10 wt % NMP) kept at 40°C under atmospheric pressure over 85 seconds to obtain a crude PPS mixture. The entire crude PPS mixture obtained was filtered to obtain a crude PPS mixture with a solids concentration of 25%.

[0066] Example 4 Step (1) was carried out in the same manner as in Example 1, step (2) was carried out in the same manner as in Example 3, and step (3) was carried out in the same manner as in Example 2. The properties of the obtained PPS resin are shown in Table 1.

[0067] <Example 5> The procedure was carried out in the same manner as in Example 1, except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 2.

[0068] Example 6 The procedure was carried out in the same manner as in Example 2, except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 2.

[0069] Example 7 The same procedure as in Example 3 was carried out except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 2.

[0070] Example 8 The same procedure as in Example 4 was carried out except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 2.

[0071] <Comparative Example 1> The procedure of Example 1 was repeated except that the resin was removed in step (2) as follows. The properties of the resulting PPS resin are shown in Table 3. After the reaction was complete, the bottom valve of the autoclave was opened and the autoclave was flushed under vacuum into a 2L vacuum agitator with an agitator blade to remove the NMP. The NMP was then removed under vacuum at 150°C for 4 hours, after which the autoclave was cooled to room temperature. A crude PPS mixture with a solids concentration of 99.5% was obtained. The properties of the resulting PPS resin are shown in Table 3.

[0072] <Comparative Example 2> The procedure of Example 2 was repeated except that the resin was removed in step (2) as follows. The properties of the resulting PPS resin are shown in Table 3. After the reaction was complete, the bottom valve of the autoclave was opened, and the autoclave was placed in a 2-liter vacuum agitator dryer equipped with an agitator blade, where it was flashed under vacuum and cooled to room temperature. A crude PPS mixture with a solids concentration of 55% was obtained. The properties of the resulting PPS resin are shown in Table 3.

[0073] <Comparative Example 3> The same procedure as in Example 1 was carried out, except that the mixed solution (10 wt % water, 90 wt % NMP) used in step (2) was changed to 100 wt % water. The properties of the obtained PPS resin are shown in Table 3.

[0074] <Comparative Example 4> Step (1) was carried out in the same manner as in Example 1, step (2) was carried out in the same manner as in Comparative Example 3, and step (3) was carried out in the same manner as in Example 2. The properties of the obtained PPS resin are shown in Table 3.

[0075] <Comparative Example 5> The same procedure as in Comparative Example 3 was carried out except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 4.

[0076] <Comparative Example 6> The same procedure as in Comparative Example 4 was carried out except that the water in the mixed solution in step (2) was changed to methanol. The properties of the obtained PPS resin are shown in Table 4.

[0077] [Table 1]

[0078] [Table 2]

[0079] [Table 3]

[0080] [Table 4]

[0081] Comparing the Examples with Comparative Examples 1 and 2 from Tables 1 to 4, the resins of the Comparative Examples, which do not satisfy the method for extracting the PAS resin in step (2) of the present invention, have an average particle diameter (D 50 ) and poor filterability. Furthermore, when packed in a column, poor liquid permeability and metal adsorption were demonstrated. Comparing the Examples with Comparative Examples 3 to 6, the Comparative Examples that did not satisfy the composition of the mixed solvent in step (2) of the present invention were poor in cleanability, and therefore had a high alkali metal content, and showed poor adsorption when used as a column.

Claims

1. a step (1) of reacting a polyhaloaromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, in an organic polar solvent (a) to obtain a crude reaction mixture containing at least a polyarylene sulfide resin, an alkali metal halide, and the organic polar solvent (a); a step (2) of directly discharging the crude reaction mixture into a solution containing an organic polar solvent (b) and a poor solvent for the polyarylene sulfide resin to bring the mixture into contact with the organic polar solvent (b) and a poor solvent for the polyarylene sulfide resin, and then removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least the polyarylene sulfide resin and the alkali metal halide; a step (3) of washing the mixture (A) to remove alkali metal halides, the amount of poor solvent contained in the solution containing the organic polar solvent (b) and the poor solvent for the polyarylene sulfide resin used in the step (2) is 10 to 90 mass %; The average particle diameter (D ５０ ) is 0.5 mm or more.

2. The loose bulk density of the obtained polyarylene sulfide resin is 250 kg / m ３ 2. The method for producing the polyarylene sulfide resin according to claim 1, wherein the polyarylene sulfide resin is:

3. 2. The method for producing a polyarylene sulfide resin according to claim 1, wherein the alkali metal content of the resulting polyarylene sulfide resin is 500 ppm or less.

4. The specific surface area of ​​the resulting polyarylene sulfide resin is 10 m ２ 2. The method for producing a polyarylene sulfide resin according to claim 1, wherein the polyarylene sulfide resin has a molecular weight of 1 / g or more.

5. A method for producing an adsorption column, comprising the steps of producing a polyarylene sulfide resin by the method according to claim 1 or 2, and packing the polyarylene sulfide resin thus obtained into a column.

6. An adsorbent comprising a polyarylene sulfide resin produced by the method of claim 1 or 2.

7. 3. A method for using the polyarylene sulfide resin produced by the method according to claim 1 or 2 as an adsorbent.

Images