Polyarylene sulfide resin and method for producing 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

Method for producing polyarylene sulfide resin and adsorption column

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

[0002] Polyarylene sulfide (hereinafter referred to as PAS) resins, typified by polyphenylene sulfide (hereinafter referred to as PPS) resins, are excellent in heat resistance, chemical resistance, and the like, and are widely used in electrical and electronic components, automobile components, water heater components, fibers, films, and the like.

[0003] Conventional, common, and relatively inexpensive methods for producing PAS resins include, for example, reacting a polyhalogenated aromatic compound with an alkali metal sulfide in an organic polar solvent, and, after polymerization, flushing the crude reaction mixture from a high-temperature, high-pressure state to a normal or reduced-pressure atmosphere to remove the polymerization solvent, followed by 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 operation, the PAS resin has a small particle size, making it difficult to filter. This not only lengthens the washing and purification steps, but also significantly impacts productivity, workability, energy costs, and other factors due to the increased size of the filtration equipment. To solve this problem, simply controlling the particle size of the PAS resin to a large size by removing the polymerization solvent using crystallization or heated distillation, etc., results in poor washability and poor end group substitution. 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, there has been a need for a method for producing PAS resins that allows the filtration and washing steps to be completed in a short time while still quickly removing the polymerization solvent.

[0004] JP 2004-99684 A JP 2012-136629 A

[0005] Therefore, an object of the present invention is to provide a method for producing a PAS resin that can perform the filtration and washing steps in a short time.

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

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

[0008] The present disclosure also relates to a method for producing an adsorption column, comprising the steps of producing a PAS resin by the above-described method and packing the obtained PAS resin into a column.

[0009] According to the present invention, it is possible to provide a method for producing a PAS resin that allows the filtration and washing processes to be performed in a short time, and a method for producing an adsorption column filled with the PAS resin that has excellent liquid permeability and adsorption capacity.

[0010] Hereinafter, one embodiment of the present invention will be described in detail, but 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. Furthermore, when multiple upper and lower limit values ​​are specified for a specific parameter, any upper and lower limit values ​​can be combined to form a suitable numerical range.

[0011] <Method for producing PAS resin> The method for producing a PAS resin according to this embodiment includes: a step (1) of reacting a polyhalo aromatic 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 crude reaction mixture into contact with the solution, and then removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least a PAS resin and an alkali metal halide; and a step (3) of washing the mixture (A) to remove the alkali metal halide, wherein the amount of poor solvent contained in the solution containing the organic polar solvent (b) and a poor solvent for the PAS resin used in the step (2) is 10 to 90 parts by mass; and the average particle diameter (D ５０ ) is 0.5 mm or more.

[0012] Step (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 an aromatic ring, and specific examples thereof include dihaloaromatic compounds such as 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, and dibromobiphenyl, and mixtures thereof, and these compounds may 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 the present embodiment, a hydrous sulfidizing agent can also be used as a raw material, and in this case, it is preferable to subject the hydrous sulfidizing agent to a polymerization reaction of the PAS resin after a step of dehydrating the agent in the presence of at least an aprotic polar solvent. Furthermore, when the amount of the aprotic polar solvent charged is small, for example, when it is 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 polyhalo aromatic 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 in the range of 80 to 220° C., more preferably in the range of 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 in the range of 0.01 to 2.0 moles, per mole of sulfur atoms in the sulfidizing agent.

[0020] Furthermore, 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 in the range of 200 to 330°C, and a pressure in a range that maintains the polymerization solvent and the polyhaloaromatic compound (polymerizable monomer) substantially in a 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 be 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 atoms in the sulfidizing agent. The amount of aprotic polar solvent charged is adjusted to be in the range of 1.0 to 6.0 mol, preferably 2.5 to 4.5 mol, per mol of sulfur atoms in the sulfidizing agent. The polymerization reaction is preferably carried out in the presence of a small amount of water, and the proportion is preferably adjusted appropriately taking into account 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 mol or less, preferably 1.6 mol or less, per mol of sulfur atoms in the sulfidizing agent. Furthermore, when the dehydration operation is carried out in the presence of a polyhaloaromatic compound (for example, the method described in "5)" in the specific embodiment below), the dehydration operation may be carried out so that the amount of water is 0.9 mol or less, preferably 0.05 to 0.3 mol, more preferably 0.01 to 0.02 mol.

[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 of carrying out a polymerization reaction in the presence of a small amount of water, followed by adding water to carry out further polymerization; 4) a method of cooling the gas phase in a reaction vessel during the reaction of an alkali metal sulfide and an aromatic dihalogen compound, condensing part of the gas phase in the reaction vessel, and refluxing it into a 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 the mixture 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 water to dehydrate the slurry; 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 the polar organic solvent such as NMP, to polymerize the slurry.

[0023] In this way, by polymerizing 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), a PAS resin is obtained as a product, but cyclic PAS oligomers are also produced 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 thought to contribute to an improvement in the specific surface area of ​​the resulting PAS resin. That is, it is thought that the alkali metal halide is incorporated when the PAS resin aggregates in the poor solvent in step (2), and then the alkali metal halide is released by washing in the subsequent step (3), resulting in porosity.

[0024] Step (2) Step (2) is a step 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.

[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, sometimes simply referred to as a "mixed solution") is not particularly limited as long as it does not impair the effects of the present invention. For example, there is a method in which the crude reaction mixture is 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 such a 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 resins include water, acetone, dimethyl sulfoxide, tetrahydrofuran, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol, alcohols having 3 or less carbon atoms and containing an ether bond, such as 2-methoxyethyl alcohol; alcohols having 3 or less carbon atoms and containing a ketone group; and alcohols having 3 or less carbon atoms and containing an ester group. Of 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, the pressure 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 even 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] Step (3) Step (3) is a step of washing the mixture (A) to remove alkali metal halides.

[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 filtering 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] During the water washing, the amount of water added to the mixture (A) is preferably in the range of 2 to 20 times the theoretical yield of the PAS resin finally obtained, from the viewpoint of washing efficiency, and the above amount of water is preferably divided into 1 to 10 times, preferably 1 to 4 times, for washing. The water washing is preferably carried out in a nitrogen or air atmosphere at a water temperature in the range of 20°C to 300°C. In terms of improving washing efficiency, it is more preferable to carry out the water washing in the range of 50°C to 100°C, and most preferably in the range of 70°C to 90°C. The water washing can be carried out once or repeatedly 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 and sulfidizing agent that have not been washed off completely, and therefore it is preferable to further bring the solid phase component into contact with water at a temperature in the range of 100°C to 280°C, followed by solid-liquid separation (hereinafter sometimes referred to as "hot water washing").

[0034] The temperature for hot water washing is, for example, preferably in the range of 100° C. to 280° C., more preferably in the range of 120° C. to 275° C., from the viewpoint of improving the efficiency of extraction 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 water under 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 operation 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 in the first hot water washing step to, for example, a temperature in the range of 120°C to 250°C, and to first remove the highly alkaline filtrate by filtration, and then to set the temperature in the second hot water washing step to a higher temperature than that in 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 the step can also be carried out in a vessel having a mixing function, which has an agitator inside the vessel and a filtration filter disposed 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 the step can also be carried out in a sealed or sealable vessel having a mixing function, which has an agitator inside the vessel and a filtration filter disposed at the bottom. In this embodiment, water washing or hot water washing may be carried out 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 may be further washed, subjected to solid-liquid separation, and dried to prepare a powdery 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 the present disclosure is measured in accordance with a conventional method using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300EXII), and the average particle size (D) at 50% of the cumulative particle size distribution curve is ５０ ) and the average particle diameter 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 or less, 200 kg / m ３ Preferably, it 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. ３ It is more preferable that the ratio of the compacted bulk density to the difference between the loose bulk density and the compacted 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 has excellent filterability, and also excellent mixability and flowability when used as a raw material for resin compositions and molded products. The loose bulk density, compacted bulk density, and compressibility in this disclosure are values ​​measured using the methods in the examples.

[0040] The PAS resin obtained by the production method according to this embodiment preferably has an alkali metal content of 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 production method according to this embodiment has a BET specific surface area of ​​10 m ２ / g or more, and ２ / g or more is more preferable, and 20m ２ / g or more is even more preferable. In such a range, the cleaning efficiency and the terminal group substitution efficiency are excellent during the purification of the PAS resin. 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 "Tristar II3020" manufactured by Shimadzu Corporation after pretreating the PAS resin particles under vacuum at 60°C for 4 hours.

[0042] <Method for manufacturing an adsorption column> The method for manufacturing an adsorption column according to this embodiment includes the steps of manufacturing a PAS resin by the manufacturing method described above and packing the obtained PAS resin into a column. The PAS resin obtained by the manufacturing method according to this embodiment has excellent filterability, and therefore has 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 the manufacturing method according to this embodiment has a large specific surface area, resulting in a large contact area with the solution and excellent adsorption ability.

[0043] The shape and material of the column are not limited, and known and publicly used materials can be used. In this embodiment, the method for packing the PAS resin into a column is not particularly limited, and known methods can be used. For example, the PAS resin is dispersed in a suitable liquid medium, such as water, to form a slurry, and then the slurry is packed into a column having a certain capacity. A solvent is then introduced by gas pressure or pump pressure to consolidate the PAS resin. When the PAS resin obtained by the above-described manufacturing method is packed into a column, the loose bulk density may change 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, and the adsorption capacity is excellent. When the PAS resin is packed into a column, a known and publicly used filter aid may also be packed in.

[0044] When the PAS resin obtained by the production 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 due to 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, ultraviolet stabilizers, ultraviolet absorbers, foaming agents, flame retardants, flame retardant assistants, rust inhibitors, release agents, and coupling agents.

[0045] The PAS resin obtained by the production method according to 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, melt-kneaded, and then molded directly or after first being pelletized, using various melt processing methods such as injection molding, extrusion molding, compression molding, and blow molding to produce molded articles with excellent heat resistance, moldability, dimensional stability, and the like. 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 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 be mixed and used in the same manner. 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 excellent in chemical resistance, heat resistance, moldability, dimensional stability, etc., similar to conventional PAS resins. Therefore, the PAS resin can be widely used, for example, in electric and electronic components such as connectors, printed circuit boards, and sealed molded products, automobile components such as lamp reflectors and various electrical components, interior materials for various buildings, aircraft, automobiles, etc., injection-molded and compression-molded products such as precision parts for office equipment parts, camera parts, and watch parts, and extrusion-molded and pultrusion-molded products such as fibers, films, sheets, and pipes.

[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 the PPS resins obtained in each of the examples and comparative examples were measured using a Powder Tester (registered trademark) PT-X manufactured by Hosokawa Micron Corporation 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 with a bottom (inner diameter 50.46 mm × depth 50 mm) 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 value of the weight measured three times 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 follows.

[0051] (Packed Bulk Density) A resin adapter (inner 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 the weight was divided by the internal volume of the bottomed cylindrical container to determine the packed bulk density (kg / m ３ ) was calculated as follows.

[0052] (Compressibility) The compressibility (%) was calculated from the values ​​of the compacted bulk density and the loose bulk density according to the following formula: Compressibility (%) = {compacted bulk density (kg / m ３ ) - loose bulk density (kg / m ３ )) / Toughened 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 the crucible to cover the resin. The resin was then completely incinerated using a microwave ashing device manufactured by Milestone General Co., Ltd. 1% hydrochloric acid and pure water were added to dissolve the ash. The resulting solution was analyzed for sodium content using an atomic absorption spectrophotometer, and the amount of sodium in the PPS was quantified from the obtained value. 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 "Tristar II 3020" manufactured by Shimadzu Corporation. The PPS resin obtained in each example and comparative example was pretreated by standing under vacuum at 60°C for 4 hours, then placed in a measurement cell, the inside of the cell was degassed, and then 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 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 Corporation) and subjected to suction filtration (vacuum pressure: 40.0 kPa). The time required for filtration was taken as the filtration time. The results are shown in Table 1. Thereafter, 1 L of 70°C ion-exchanged water was added to the filtered cake and subjected to suction filtration (vacuum pressure: 40.0 kPa). The times required for filtration are shown in Tables 1 and 2. Resins requiring shorter filtration times 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 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) was represented as "○" if less than 1, "△" if 1 to 10, and "×" if 10 or more.

[0058] (7) Evaluation of Adsorption Ability The undried PPS resin obtained in each Example and Comparative Example was placed in a test tube so that the PPS resin amounted to 0.005 g, and 5.0 mL of palladium solution was added thereto. This was shaken and stirred horizontally at 200 rpm at a liquid temperature of 30°C using a shaker ("SA300" manufactured by Yamato Scientific Co., Ltd.) for 3 hours. Thereafter, the liquid phase component and the PPS resin were recovered by filtration. The concentration of palladium in the liquid phase component was quantified using an atomic absorption spectrophotometer, and the solution concentration before adsorption (C ０ The adsorption rate (%) is calculated using the concentration of the solution after adsorption (C), and is represented as "◎" for 60% or more, "◯" for less than 60% and 30% or more, "△" for less than 30% and 10% or more, and "×" for less than 10%. Adsorption rate (%) = (C ０ -C) / C ０ ×100

[0059] Example 1 Step (1) 244.02 g (1.66 mol) of DCB, 26.96 g (0.16 mol) of NMP, 201.78 g of a 47.23 wt% aqueous NaSH solution (1.70 mol as NaSH), and 135.74 g of a 49.21 wt% aqueous NaOH solution (1.67 mol as NaOH) were charged into a 1 L autoclave equipped with a stirring blade and connected to a pressure gauge, thermometer, condenser, decanter, and rectification column. 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. DCB distilled azeotropically during dehydration was separated using a decanter and returned to the kettle as needed. After completion of dehydration, the anhydrous sodium sulfide composition was dispersed in the DCB in the kettle. 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 connecting 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 was 110°C or less. 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] Step (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] Step (3): 600 g of 70°C ion-exchanged water was added to 100 g of the obtained crude PPS mixture, 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 obtained 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 obtained PPS resin are shown in Table 1.

[0062] Example 2 Step (1) was carried out in the same manner as in Example 1.

[0063] Step (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 amount of the obtained crude PPS mixture was filtered to obtain a crude PPS mixture with a solids concentration of 25%.

[0064] Step (3): 600 g of 70°C ion-exchanged water was added to 100 g of the obtained crude PPS mixture, 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 then added to the filtered cake for cake washing. Another 600 g of 25°C ion-exchanged water was then added, stirred for 30 minutes, and filtered. 1 L of 25°C ion-exchanged water was then added to the filtered cake for cake washing. The mixture was then dried at 120°C for 4 hours. The properties of the obtained PPS resin are shown in Table 1.

[0065] Example 3 The same procedure as in Example 1 was carried out, except that the resin removal operation in step (2) was performed as follows. The properties of the obtained PPS resin are shown in Table 1. The composition obtained in step (1) was removed over 85 seconds into 1 L of a mixed solution (90 wt % water, 10 wt % NMP) kept at 40°C under atmospheric pressure, to obtain a crude PPS mixture. The entire amount of the obtained crude PPS mixture 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 same procedure as in Example 1 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.

[0068] Example 6 The same procedure as in Example 2 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.

[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 same procedure as in Example 1 was carried out, except that the resin removal operation in step (2) was performed as follows. The properties of the resulting PPS resin are shown in Table 3. After completion of the reaction, the bottom valve of the autoclave was opened, and the autoclave was flushed under vacuum in a 2-L vacuum agitator dryer equipped with an agitator blade to remove NMP, and the NMP was 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 same procedure as in Example 2 was carried out, except that the resin removal operation in step (2) was performed as follows. The properties of the resulting PPS resin are shown in Table 3. After completion of the reaction, the bottom valve of the autoclave was opened, and the autoclave was flashed under vacuum in a 2-L vacuum agitator dryer equipped with an agitator blade, 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 procedure was the same as in Example 1, 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]

[0078]

[0079]

[0080]

[0081] Comparing the Examples with Comparative Examples 1 and 2 from Tables 1 to 4, the resins of the Comparative Examples that 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 mixed solvent composition 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. The method comprises the steps of: (1) reacting a polyhalo aromatic 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 an organic polar solvent (a); (2) directly discharging the crude reaction mixture into a solution containing an organic polar solvent (b) and a poor solvent for the polyarylene sulfide resin, contacting the crude reaction mixture with the solution, and then removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least a polyarylene sulfide resin and an alkali metal halide; and (3) washing the mixture (A) to remove the alkali metal halide, wherein the amount of poor solvent contained in the solution containing the organic polar solvent (b) and a poor solvent for the polyarylene sulfide resin used in the step (2) is 10 to 90 parts by mass; and 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 The method for producing the polyarylene sulfide resin according to claim 1, wherein the polyarylene sulfide resin is:

3. 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 The method for producing the polyarylene sulfide resin according to claim 1, wherein the molecular weight of the polyarylene sulfide resin is 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 the polyarylene sulfide resin produced by the method according to claim 1 or 2.

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

8. Average particle diameter (D ５０ ) is 0.5 mm or more, and the loose bulk density is 250 kg / m ３ A polyarylene sulfide resin, which is:

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