JP2024021680A - Production method of composition containing polyarylene sulfide oligomer, and production method of crosslinked polyarylene sulfide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a polyarylene sulfide (PAS) oligomer mixture which controls a ring opening rate of a cyclic PAS oligomer included in an organic polar solvent filtered in a production step of a PAS resin, to concentrate the oligomer.

SOLUTION: There is provided a production method of a PAS oligomer mixture which includes the steps of: reacting, in an organic polar solvent, a polyhalo aromatic compound with (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide to obtain a crude reaction mixture containing a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide and an organic polar solvent; removing a solid-phase component from the mixture to obtain a liquid-phase component (A) containing a PAS oligomer; and concentrating the liquid-phase component (A) at 230°C-280°C under a reduced pressure or normal pressure environment to obtain a PAS oligomer mixture (B), wherein a ring opening rate of the cyclic PAS oligomer during concentration is 10% or more. There is also provided a production method of a PAS resin using the mixture.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention provides a method for producing a polyarylene sulfide oligomer mixture, in which the ring-opening rate of a cyclic polyarylene sulfide oligomer contained in a liquid phase component filtered out in a polyarylene sulfide resin production process is controlled and concentrated; The present invention relates to a method for producing a crosslinked polyarylene sulfide resin in which it is added with high efficiency.

Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) resin, represented by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) resin, has excellent heat resistance, chemical resistance, etc., and is used in electrical and electronic parts, automobile parts, It is widely used for water heater parts, textiles, films, etc.

The PPS resin can be obtained by a method of polymerizing a sulfidizing agent and a polyhaloaromatic compound in a polar organic solvent such as N-methyl-2-pyrrolidone (NMP). At this time, by-products such as PPS oligomers, residual sulfidating agents, and sodium chloride are also produced, but these by-products are considered impurities and have not been utilized in the past. In particular, most of the PPS oligomers contained in the liquid phase component obtained by solid-liquid separation of the solvent slurry after polymerization are discarded as industrial waste, resulting in significant production losses in terms of raw material cost loss and disposal cost. I was invited.

Until now, a method for recovering the above-mentioned liquid phase component as a polymerization raw material has been disclosed (see Patent Document 1). However, since impurities (such as phenol) other than the PPS oligomer present in the liquid phase component inhibit the polymerization reaction, the reuse rate as a raw material has been limited.

JP2017-114922A

Therefore, the problem to be solved by the present invention is to create a composition containing a PAS oligomer in which the ring-opening rate of the cyclic oligomer is controlled to 10% or more, which is obtained by solid-liquid separation of the crude reaction mixture after the polymerization reaction of the PAS resin. The goal is to provide a method for manufacturing things. Furthermore, a method for producing a crosslinked PAS resin is provided in which a composition containing a PAS oligomer obtained by the above production method is reused as an additive for PAS resin, thereby improving the reuse rate of the oligomer and reducing loss. The goal is to provide a way to do so.

As a result of various studies, the inventors of the present application have determined that the liquid phase component obtained by solid-liquid separation of the reaction mixture obtained after the polymerization reaction of PAS resin is concentrated at 230°C or lower in a reduced pressure or normal pressure environment. By going through the steps, it is possible to produce a composition containing a PAS oligomer in which the ring opening rate of the cyclic PAS oligomer contained in the liquid phase component is controlled to 10% or more, and the composition containing the PAS oligomer can be used to produce a PAS resin. The present inventors have discovered that the addition of a substance can improve the reuse rate of oligomers, as well as improve the crosslinking rate and thermal stability of the resulting crosslinked PAS resin, and have completed the present invention. Ta.

That is, the present invention [1] reacts 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. step (1) of obtaining a crude reaction mixture containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent; (2) to obtain a liquid phase component (A) containing at least a cyclic PAS oligomer and a chain PAS oligomer, and supplying the liquid phase component (A) into an evaporator and under reduced pressure or normal conditions. comprising a step (3) of concentrating the liquid phase component (A) at 230° C. or lower in a pressure environment to obtain a PAS oligomer mixture (B); The present invention relates to a method for producing a PAS oligomer mixture, characterized in that the ring opening rate is 10% or more.

Furthermore, the present invention provides a method for reacting [2] 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. step (5) of obtaining a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and an organic polar solvent, adding the PAS oligomer mixture obtained by the production method according to claim 1 to the crude reaction mixture; Step (6) of obtaining a mixture (C) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent, solid-liquid separation of the mixture (C) by a flash method, Step (7) of obtaining a mixture (D) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, and an alkali metal halide, washing the mixture (D) to remove the alkali metal halide, and at least the PAS resin , characterized by comprising a step (8) of obtaining a mixture (E) containing a cyclic PAS oligomer and a chain PAS oligomer, and a step (9) of heat-treating the mixture (E) in an oxidizing atmosphere. The present invention relates to a method for producing a crosslinked PAS resin.

Furthermore, the present invention provides a method for reacting [3] 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. step (5) of obtaining a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and an organic polar solvent; solid-liquid separation of the crude reaction mixture by a flash method; Step (10) of obtaining a solid content (F): Adding to the solid content (F) a PAS oligomer mixture that has undergone a step of further contacting the oligomer mixture (B) described in [1] with water to form a slurry. to obtain a mixture (G) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, and an alkali metal halide (11), washing the mixture (G) to remove the alkali metal halide, It is characterized by comprising a step (12) of obtaining a mixture (H) containing at least a PAS resin, a cyclic PAS oligomer, and a chain PAS oligomer, and a step (13) of heat-treating the mixture (H) in an oxidizing atmosphere. The present invention relates to a method for producing a crosslinked PAS resin.

In the present invention, a polymer compound having 2 to 40 repeating units (a mixture of dimers to 40-mers) may be referred to as an "oligomer."

According to the present invention, there is provided a method for concentrating a cyclic PAS oligomer that is filtered out after a polymerization reaction of a PAS resin while controlling the ring opening rate, and a method for producing a crosslinked PAS resin in which the PAS oligomer is recovered with higher efficiency. method can be provided.

<Method for producing PAS oligomer mixture>
The present invention comprises 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, and at least Step (1) of obtaining a crude reaction mixture containing a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent;
Step (2) of removing the solid phase component from the crude reaction mixture by solid-liquid separation to obtain a liquid phase component (A) containing at least a cyclic PAS oligomer and a chain PAS oligomer;
Step (3) of supplying the liquid phase component (A) into an evaporator and concentrating the liquid phase component (A) at 230 ° C. or lower in a reduced pressure or normal pressure environment to obtain a PAS oligomer mixture (B). have, and
Step (3) is characterized in that the ring opening rate of the cyclic PAS oligomer upon concentration is 10% or more. The details will be explained below.

Process (1)
Step (1) involves 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, This is a step of obtaining a crude reaction mixture containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent.

The mixture used in step (1) is not particularly limited as long as it is a mixture containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent, but is preferably used in step (1). It is preferable to use a crude reaction mixture obtained in the method for producing a PAS resin used in the present invention described below in (5).

Process (2)
Step (2) is a step of removing a solid phase component from the crude reaction mixture by solid-liquid separation to obtain a liquid phase component (A) containing at least a cyclic PAS oligomer and a chain PAS oligomer.

The solid-liquid separation is roughly divided into two types: a flash method and a quench method, which will be described later. The flash method is a method in which the solvent in the crude reaction mixture is evaporated to recover the solvent and solids are recovered at the same time.Generally, the crude reaction mixture is flashed from a high temperature and high pressure state into an atmosphere at normal pressure or reduced pressure. In this method, the solvent is distilled off and recovered, and at the same time, the solid material containing the PAS resin is turned into powder and recovered. A preferred embodiment of the flash method is a method in which the high temperature and high pressure (usually 250° C. or higher, 0.8 MPa or higher) polymerization reaction product obtained in the polymerization step is ejected from a nozzle into an atmosphere of nitrogen or water vapor at normal pressure. It will be done. In the flash method, the solvent can be efficiently recovered by utilizing the heat of vaporization of the solvent when the polymerization reaction product is flashed from a high temperature and high pressure state to a normal pressure state, but the higher the internal temperature during flashing, the faster the solvent recovery will be. Efficiency is improved and productivity is also improved. Therefore, the temperature and pressure within the polymerization system during flashing are usually set at 250° C. or higher, preferably in the temperature range of 255 to 280° C., and in the pressure range of 0.8 MPa or higher, preferably 1.0 to 5.0 MPa. From this state, when flashing under reduced pressure or normal pressure, the atmospheric temperature is usually in the range of 150 to 250°C, and if the solvent recovery from the crude reaction mixture is insufficient, after flashing, the atmosphere temperature is in the range of 150 to 250°C. You may continue heating.

On the other hand, the quench method is a method of gradually cooling the crude reaction mixture to recover particulate PAS resin. Generally, the crude reaction mixture is gradually cooled from a high temperature and high pressure state to recover the PAS resin in the reaction system. This is a method in which the solid content containing the PAS resin is recovered as granules by crystallizing the PAS resin and then performing solid-liquid separation by filtration or the like. There is no particular restriction on the cooling time, but the preferred range is usually 0.1°C/min to 3°C/min. In addition, there is no need to slow-cool at the same rate throughout the slow-cooling process; the speed should be in the range of 0.1°C/min to 1°C/min until the PAS resin granules crystallize, and then 1°C/min thereafter. A method of cooling at a rate of 1 minute or more is also preferable. It is preferable to finally cool the mixture to 70° C. or higher, preferably 100° C. or higher and 200° C. or lower, and then perform solid-liquid separation to recover the solid content containing the PAS resin. Solid-liquid separation in the quench method is performed by separating using filtration or a centrifugal separator such as a screw decanter, then adding water directly to the resulting filtration residue to form a slurry, and then repeating solid-liquid separation, or by repeatedly performing solid-liquid separation. For example, the remaining solvent may be removed by heating the filtration residue under a non-oxidizing atmosphere. The quench method is more preferable in this step because it makes it difficult for impurities such as the by-products and unreacted raw materials to be incorporated into the polymer particles during crystallization, and more PAS oligomers can be recovered.

Process (3)
Step (3) is to supply the liquid phase component (A) into an evaporator and concentrate the liquid phase component (A) at 230°C to 280°C in a reduced pressure or normal pressure environment to form a PAS oligomer mixture (B). ).

The evaporator used in this step is not particularly limited as long as it is made of a material that is resistant to organic polar solvents and is a container that can be heated and depressurized, and any known evaporator can be used, such as an evaporator, autoclave, thin film evaporator, etc. can be mentioned.

The temperature inside the evaporator when concentrating the liquid phase component (A) is preferably 230°C or higher, and preferably 280°C or lower. Further, the pressure inside the evaporator is preferably below normal pressure, and specifically preferably in the range of 10 to 760 mmHg. By concentrating under such conditions, the ring opening rate of the cyclic PAS oligomer can be controlled to 10% or more. Note that the ring opening rate is expressed by the following formula.
Ring opening rate (%) = {1-(weight fraction of cyclic PAS oligomer to PAS oligomer contained in PAS oligomer mixture (B))/(cyclic PAS oligomer to PAS oligomer contained in liquid phase component (A)) weight fraction)}×100

Further, when concentrating the liquid phase component (A), the proportion of solids (nonvolatile matter) contained in the PAS oligomer mixture (B) is 20 to 100% by mass, preferably 20 to 99.99% by mass, more preferably It is desirable to adjust the amount of solvent removed so that it is in the range of 30 to 90% by mass.

By controlling the ring opening rate of the cyclic PAS oligomer to 10% or more in this step, in the production of PAS resin using the resulting PAS oligomer mixture, the crosslinking rate can be improved, the heat treatment time can be shortened, and the resulting crosslinked type can be improved. The melt stability of PAS resin can be improved.

When a cyclic PAS oligomer is ring-opened by heat or the like, it becomes a chain PAS oligomer having an SH group or the like. When this chain oligomer is further heat-treated in an oxidizing atmosphere, a portion thereof becomes active species such as thiyl radicals (S.). When this chain PAS oligomer is added to the PAS resin in the manufacturing process of crosslinked PAS resin, the chain PAS oligomer becomes an active species in the heat treatment process and promotes coupling between PAS resins, so the crosslinking rate is reduced. can be improved. This effect is small when the cyclic PAS oligomer is added to the PAS resin and heat treated. This is because, in the heat treatment step, radicalization of SH groups and the like by ring opening of the cyclic PAS oligomer takes precedence over conversion into active species. If the crosslinking rate is low and the heat treatment takes a long time, active species such as oxygen radicals generated from sources other than the chain PAS oligomers are generated and accumulated in the PAS resin, which may lead to significant thickening during melting. Therefore, by increasing the crosslinking rate and shortening the heat treatment time, the resulting crosslinked PAS resin is suppressed from increasing in viscosity during melting, and its melt stability is improved.

The PAS oligomer mixture obtained through steps (1) to (3) may be used as it is, or may be used after further extraction and purification of the PAS oligomer. In that case, chain PAS oligomers and/or cyclic PAS oligomers can be obtained by performing known extraction and purification operations on the PAS oligomer mixture.

Process (4)
Step (4) may further include a step of bringing the oligomer mixture (B) into contact with water to form a slurry. By forming it into a slurry, it is possible to improve the accuracy of preparing the mixture (B) and reduce the stirring load when adding it in the PAS resin manufacturing process.

The amount of water brought into contact with the oligomer mixture (B) is preferably in the range of 0.01 to 10 times the mass of the PAS resin. Further, the temperature of the water is preferably room temperature or higher, specifically preferably in the range of 20 to 90°C.

<Method for manufacturing PAS resin composition>
The method for producing a PAS resin of the present invention comprises combining a polyhaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent. Step (5) of reacting to obtain a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and an organic polar solvent, adding the PAS oligomer mixture obtained by the production method described in [1] to the crude reaction mixture. (6) to obtain a mixture (C) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent; solid-liquid separation of the mixture (C) by a flash method; step (7) of removing the liquid phase component to obtain a mixture (D) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, and an alkali metal halide; washing the mixture (D); Step (8) of removing the halide to obtain a mixture (E) containing at least a PAS resin, a cyclic PAS oligomer, and a chain PAS oligomer; and a step (9) of heat-treating the mixture (E) in an oxidizing atmosphere. ).

Alternatively, the method for producing a PAS resin of the present invention comprises combining a polyhaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent. step (5) of obtaining a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and an organic polar solvent, and solid-liquid separation of the crude reaction mixture by a flash method to remove liquid phase components. , a step (10) of obtaining a solid content (F) containing at least a PAS resin and an alkali metal halide; the solid content (F) is further brought into contact with the oligomer mixture (B) described in [1] with water to form a slurry; step (11) of adding the PAS oligomer mixture that has undergone the step of converting into a mixture to obtain a mixture (G) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, and an alkali metal halide; washing the mixture (G); and removing the alkali metal halide to obtain a mixture (H) containing at least a PAS resin, a cyclic PAS oligomer, and a chain PAS oligomer (12), and heating the mixture (H) in an oxidizing atmosphere. It has a step (13). The details will be explained below.

Process (5)
Step (5) involves reacting the polyhaloaromatic compound with (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent, This is a step of obtaining a crude reaction mixture containing at least a PAS resin, an alkali metal halide, and an organic polar solvent.

Here, in the present invention, the polyhaloaromatic compound is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring, and specifically, p-dichlorobenzene, o -Dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromnaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromodiphenylbenzene, dichlor Dihaloaromatic compounds such as benzophenone, dibrombenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlordiphenyl sulfide, dibromodiphenylsulfide, dichlorbiphenyl, dibrombiphenyl, and mixtures thereof are mentioned, and these compounds can be blocked. May be copolymerized. Among these, preferred are dihalogenated benzenes, and particularly preferred are those containing 80 mol% or more of p-dichlorobenzene. Further, in order to increase the viscosity of the PAS resin by creating a branched structure, a polyhaloaromatic compound having three or more halogen substituents in one molecule may be used as a branching agent as desired. Examples of such polyhaloaromatic compounds include 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, and 1,4,6-trichloronaphthalene. Furthermore, polyhaloaromatic compounds having functional groups with active hydrogen such as amino groups, thiol groups, and hydroxyl groups can be mentioned, and specifically, 2,6-dichloroaniline, 2,5-dichloroaniline, etc. , 2,4-dichloroaniline, dihaloanilines such as 2,3-dichloroaniline; 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,4,6-trichloroaniline, 3, Trihaloanilines such as 4,5-trichloroaniline; dihaloaminodiphenyl ethers such as 2,2'-diamino-4,4'-dichlorodiphenyl ether and 2,4'-diamino-2',4-dichlorodiphenyl ether Examples include compounds in which the amino group is replaced with a thiol group or a hydroxyl group in a mixture thereof. In addition, active hydrogen-containing polyhaloaromatic compounds in which the hydrogen atom bonded to the carbon atom forming the aromatic ring in these active hydrogen-containing polyhaloaromatic compounds are substituted with other inert groups, for example, hydrocarbon groups such as alkyl groups. Aromatic compounds can also be used.

Among these various active hydrogen-containing polyhaloaromatic compounds, active hydrogen-containing dihaloaromatic compounds are preferred, and dichloroaniline is particularly preferred.

Examples of polyhaloaromatic compounds having a nitro group include mono- or dihalonitrobenzenes such as 2,4-dinitrochlorobenzene and 2,5-dichloronitrobenzene; 2-nitro-4,4'-dichlorodiphenyl ether, etc. dihalonitrodiphenyl ethers; dihalonitrodiphenyl sulfones such as 3,3'-dinitro-4,4'-dichlorodiphenylsulfone; 2,5-dichloro-3-nitropyridine, 2-chloro-3,5 - Mono- or dihalonitropyridines such as dinitropyridine; or various dihalonitronaphthalenes.

Further, in the present invention, an alkali metal sulfide or an alkali hydrosulfide and an alkali metal hydroxide (hereinafter sometimes referred to as a sulfidating agent) are used as raw materials.

In the present invention, 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 or aqueous mixtures or as anhydrides. Moreover, an alkali metal sulfide can also be derived by a reaction between an alkali metal hydrosulfide and an alkali metal hydroxide. Note that a small amount of alkali metal hydroxide may be added in order to react with alkali metal hydrosulfide and alkali metal thiosulfate, which are usually present in a small amount in the alkali metal sulfide.

Further, the alkali metal hydrosulfide includes lithium hydrogen sulfide, sodium hydrogen sulfide, rubidium hydrogen sulfide, cesium hydrogen sulfide, and mixtures thereof. Such alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or as anhydrides.

Further, 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, cesium hydroxide, etc. Each of these may be used alone, or two or more types may be used in combination. It may also be used as Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred because they are easily available, and sodium hydroxide is particularly preferred.

The method for producing PAS resin of the present invention can also use a hydrous sulfidating agent as a raw material. In that case, the PAS resin is It is preferable to subject it to a polymerization reaction. In addition, when the amount of the aprotic polar solvent charged is small, for example, when it is less than 1 mol per 1 mol of sulfur atoms of the sulfidating agent, in the presence of the polyhaloaromatic compound, the water-containing sulfidating agent and the non-protic polar solvent are It is preferable to dehydrate the protic polar solvent.

The dehydration step of the hydrous sulfidating agent is performed by adding 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 sulfidating agent to a reaction vessel equipped with a distillation apparatus. Water is removed by distillation by heating to a temperature at which water is removed azeotropically, specifically in the range of 300°C or lower, preferably in the range of 80 to 220°C, more preferably in the range of 100 to 200°C. This is done by discharging it out of the system. In the dehydration step, dehydration is performed until the amount of water in the system performing the polymerization reaction becomes 5 mol or less, more preferably in the range of 0.01 to 2.0 mol, per 1 mol of sulfur atoms of the sulfidating agent. It is preferable.

In the present invention, examples of organic polar solvents include formamide, acetamide, N-methylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam. , ε-caprolactam, hexamethylphosphoramide, N-dimethylpropylene urea, amides such as 1,3-dimethyl-2-imidazolidinonic acid, urea and lactams; sulfolanes such as sulfolane and dimethylsulfolane; benzonitrile, etc. nitriles; ketones such as methylphenylketone and mixtures thereof; among these, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethyl Amides having an aliphatic cyclic structure such as phosphoramide, N-dimethylpropylene urea, and 1,3-dimethyl-2-imidazolidinonic acid are preferred, and N-methyl-2-pyrrolidone is more preferred.

The polymerization reaction of the PAS resin in the PAS polymerization step involves reacting the alkali metal sulfide as a sulfidating agent with a polyhaloaromatic compound in the presence of these organic polar solvents. Alternatively, in the polymerization reaction of the PAS resin, the alkali metal hydrosulfide and alkali metal hydroxide as a sulfidizing agent are reacted with a polyhaloaromatic compound in the presence of these organic polar solvents. Polymerization conditions generally range from 200 to 330° C. and pressure should be such as to maintain the polymerization solvent and monomer polyhaloaromatic substantially in the liquid phase, generally 0. The pressure is selected from the range of 1 to 20 MPa, preferably 0.1 to 2 MPa. The amount of the polyhaloaromatic compound charged is in the range of 0.2 mol to 5.0 mol, preferably in the range of 0.8 to 1.3 mol, more preferably in the range of 0.8 to 1.3 mol, per 1 mol of sulfur atom of the sulfidating agent. The amount is adjusted to be in the range of 0.9 to 1.1 mol. Further, the amount of the aprotic polar solvent to be charged is in the range of 1.0 to 6.0 mol, preferably in the range of 2.5 to 4.5 mol, per 1 mol of sulfur atom of the sulfidating agent. adjust. Note that the polymerization reaction is preferably carried out in the presence of a small amount of water, and the ratio is preferably adjusted as appropriate in consideration of the polymerization method, the molecular weight of the resulting polymer, and productivity. Specifically, dehydration is performed so that the amount is 2.0 mol or less, preferably 1.6 mol or less, per 1 mol of sulfur atoms of the sulfidating agent, and further dehydration is performed in the presence of a polyhaloaromatic compound. When performing the operation (for example, the method "5)" in the following specific embodiment), 0.9 mol or less, preferably 0.05 to 0.3 mol, more preferably 0.01 to 0.02 mol or less The dehydration operation may be performed so that the

Specific embodiments of polymerizing the sulfidating agent and the polyhaloaromatic compound in the presence of the aprotic polar solvent described above include, for example,
1) A method using a polymerization aid such as an alkali metal carboxylate or 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, and then adding water and further polymerizing;
4) A method of cooling the gas phase portion of the reaction vessel during the reaction between the alkali metal sulfide and the aromatic dihalogen compound to condense a portion of the gas phase in the reaction vessel and refluxing it to a liquid phase;
5) In the presence of a polyhaloaromatic compound, an alkali metal sulfide, or a hydrous alkali metal hydrosulfide and an alkali metal hydroxide, and an amide, urea or lactam having an aliphatic cyclic structure are reacted while being dehydrated. After producing the slurry, a polar organic solvent such as NMP is further added and water is distilled off to perform dehydration. In the resulting slurry, a polyhaloaromatic compound, an alkali metal hydrosulfide, and an alkali metal salt of the hydrolyzate of an amide, urea, or lactam having an aliphatic cyclic structure are mixed in 1 mol of a polar organic solvent such as NMP. On the other hand, there is a method for producing a PAS resin which has as an essential production step a step of polymerizing the reaction in a state where the amount of water present in the reaction system is 0.02 mol or less.

In this way, by polymerizing a dihaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent, A PAS resin is obtained as a product, but in addition to that, a cyclic PAS oligomer and a chain PAS oligomer are also produced as by-products. The substances contained after the reaction may also include by-products such as an alkali metal-containing inorganic salt, a carboxyalkylamino group-containing compound, a terminal SH group-containing compound, unreacted raw materials, and water.

Process (6)
Step (6) is to add the PAS oligomer mixture obtained by the production method described in [1] to the crude reaction mixture to prepare a mixture containing at least a PAS resin, a PAS oligomer, an alkali metal halide and an organic polar solvent ( This is the process of obtaining C).

The amount of the PAS oligomer mixture added to the crude reaction mixture is preferably 0.1% by mass or more, more preferably 3% by mass or more of the PAS oligomer based on the PAS resin contained in the crude reaction mixture. Further, it is preferably 40% by mass or less, more preferably 10% by mass or less.

Process (7)
In step (7), the mixture (C) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, an alkali metal halide, and an organic polar solvent is subjected to solid-liquid separation by a flash method to separate at least the PAS resin, the PAS oligomer, and the organic polar solvent. This is a step of obtaining a mixture (D) containing an alkali metal halide.

Solid-liquid separation by the flash method in this step can be performed in the same manner as in step (2). It is preferable to recover the liquid phase component by solid-liquid separation using a flash method because the oligomer can be recovered to the product side with high efficiency.

Process (8)
Step (8) is to wash the mixture (D) containing at least a PAS resin, a cyclic PAS oligomer, a chain PAS oligomer, and an alkali metal halide, and remove the alkali metal halide to remove at least a PAS resin, a cyclic PAS oligomer, and an alkali metal halide. This is a step of obtaining a mixture (E) containing chain PAS oligomers.

In this step, the mixture (D) is washed with water or hot water. After washing with water, the PAS resin is separated by filtration to perform solid-liquid separation, for example, a reaction slurry obtained by solid-liquid separation of the aprotic polar solvent from the crude reaction mixture obtained in the PAS manufacturing process described below A method in which water is added to the mixture, stirred, and then filtered using a filtration device, and water is added again to the filtration residue containing water obtained by the above-mentioned filtration (hereinafter abbreviated as "water-containing cake") to form a slurry. Examples include a method in which the cake is filtered afterwards, or a method in which water is added again to the water-containing cake while it is held in a filter and the cake is filtered.

During the water washing, the amount of water added to the mixture (D) is preferably in the range of 2 to 10 times the theoretical yield of the PAS resin finally obtained, and is preferably in the range of 2 to 10 times the theoretical yield of the PAS resin finally obtained. It is preferable to divide the amount of water into 2 to 10 times, preferably 2 to 4 times, for washing with water. The washing with water is preferably carried out in a nitrogen or air atmosphere at a water temperature in the range of 20°C to 300°C, and more preferably in the range of 50°C to 100°C for better cleaning efficiency. Furthermore, it is most preferable to conduct the reaction at a temperature in the range of 70°C to 90°C. The water washing can be repeated once or multiple times. When water washing is repeated multiple times, the atmosphere and temperature conditions may be the same or different.

Since trace amounts of alkali metal halides and sulfidating agents may remain in the filtered PAS resin without being sufficiently washed, the resin was further contacted with water in the range of 100°C to 280°C. Afterwards, solid-liquid separation (hereinafter sometimes referred to as "hot water washing") can be performed.

The temperature of hot water washing is preferably in the range of 100 to 280°C, and more preferably in the range of 120 to 275°C, since the extraction efficiency of the alkali metal halide and sulfidating agent remaining in the resin is good. preferred. More specifically, the extraction treatment can be carried out with hot water at 140 to 260°C under the condition that the pressure of the gas phase in the reactor is increased, preferably 0.2 to 4.6 MPa (gauge pressure). preferable.

A specific method for carrying out such hot water washing includes a method of washing the PAS resin filtered off after the water washing with water in a pressure vessel under stirring under predetermined pressure and temperature conditions. It is preferable that the amount of water during washing with hot water is 1.5 to 10 times the mass of the PAS resin in order to improve the extraction efficiency of the alkali metal halide and sulfidating agent. The hot water washing may be carried out in two or more times. For example, when hot water washing is repeated twice, filtration is performed between the first hot water washing and the second hot water washing, and the alkali metal halide and sulfidating agent extracted in the first hot water washing are combined with the PAS resin. It is preferable to separate by filtration. Alternatively, filtration may be performed after washing with hot water once, and the above-described washing with water may be performed. This operation can also facilitate the separation and removal of the alkali metal halide and sulfidating agent from the PAS resin. Furthermore, the conditions for the first hot water washing step and the second hot water washing step can be arbitrarily selected from the above conditions, but the temperature for the first hot water washing step is, for example, within the range of 120°C to 200°C. After setting and first filtering and removing the highly alkaline filtrate, the temperature of the second hot water washing step is set to a temperature higher than the temperature of the first hot water washing step, for example, a temperature in the range of 150 ° C. to 275 ° C. It is preferable to carry out the hot water washing from the viewpoint of chemical resistance of the equipment used in the hot water washing.

In addition, in this step, the pH can be adjusted by adding an acid or a base during washing, and in particular, the pH after washing with hot water is 9.5 or more and less than 13.5, preferably 11.0 or more and less than 13.0. It is preferable to control it so that it is less than 12.0, more preferably in the range of 12.0 or more and less than 13.0. Examples of acids used in this case include hydrochloric acid, sulfuric acid, carbonic acid, acetic acid, and oxalic acid. Among these, carbonic acid, acetic acid, and oxalic acid are preferred. Alternatively, carbon dioxide gas may be introduced and brought into contact under normal pressure or increased pressure. On the other hand, examples of the base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, or sodium carbonate, ammonium carbonate, and sodium phosphate, and among these, sodium hydroxide is preferred.

Moreover, in the step of performing main hot water washing, a PAS oligomer mixture obtained by the production method described in [1] or [2] may be further added. The amount of the PAS oligomer mixture to be added is preferably 0.1% by mass or more, more preferably 3% by mass or more, based on the PAS resin contained in the mixture (D). Further, it is preferably 40% by mass or less, more preferably 10% by mass or less.

Further, in this step, hot water washing and solid-liquid separation can be repeated. In that case, the pH after each hot water wash can be individually adjusted to different values.

In this process, it is possible to use a washing tank with an agitator and a centrifugal separator for solid-liquid separation; It can also be carried out in a container with a mixing function. In addition, even for hot water washing exceeding 100°C, it is possible to use a washing tank with an agitator to carry out the hot water washing, and a centrifuge for subsequent filtration at 20 to 100°C. It is also possible to conduct the mixing in a closed type container having wings and a filtration filter disposed at the bottom or a container having a mixing function that can be closed. In the present invention, water washing or hot water washing may be carried out continuously or batchwise.

The filtered PAS resin is collected, and then it can be dried as it is and used as a PAS resin powder, or it can be further washed, separated into solid and liquid, and dried to be used as a powder or granular PAS resin. It can also be prepared.

Process (9)
Step (9) is a step of heat-treating the mixture (E) containing at least the PAS resin, cyclic PAS oligomer, and chain PAS oligomer obtained in step (8) in an oxidizing atmosphere.

This heat treatment in an oxidizing atmosphere (hereinafter sometimes referred to as "thermal oxidative crosslinking treatment") involves heat treating the mixture (E) in an oxidizing atmosphere such as air or oxygen-enriched air. There are several ways to do this. The heat treatment may be performed using an extruder or the like at a temperature above the melting point of the PAS resin in a molten state, but since the possibility of thermal deterioration of the PAS resin increases, it should be performed at a temperature below the melting point plus 100°C. is preferred. In addition, when heat-treating in a solid state below the melting point, from the viewpoint of the time required for heat treatment and the thermal stability of the PAS resin when melting after heat treatment, it is necessary to heat the PAS resin at 180 ° C. The temperature range is preferably 20° C. lower than the melting point. However, the melting point here refers to the value measured in accordance with JIS K 7121 using a differential scanning calorimeter (DSC device Pyris Diamond manufactured by PerkinElmer).

The oxygen concentration of the oxidizing atmosphere is preferably in the range from 5 to 30% by volume, particularly preferably from 10 to 25% by volume. If it exceeds the above range, the amount of radicals generated increases, the viscosity increases significantly during heat treatment, and the hue becomes dark, which is not preferable. If it is less than the above range, the oxidation rate becomes slow and the treatment takes a long time, which is not preferable.

The crosslinked PAS resin obtained by the production method of the present invention has a non-Newtonian index of 1.26 to 2.00, preferably 1.30 to 1.95, more preferably 1. It ranges from .35 to 1.90. Furthermore, the crosslinked PAS resin of the present invention has a melt viscosity (V6) measured at 300°C in the range of 20 to 5,000 [Pa·s], more preferably 50 to 2,000 [Pa·s]. The range is more preferably 100 to 1,000 [Pa·s].

Process (10)
In step (10), the crude reaction mixture containing at least the PAS resin, the alkali metal halide, and the organic polar solvent is subjected to solid-liquid separation by a flash method to remove liquid phase components, and at least the PAS resin and the alkali metal halide are removed. This is a step of obtaining a solid content (F) containing. Solid-liquid separation by the flash method in this step can be performed in the same manner as in step (2). It is preferable to recover the liquid phase component by solid-liquid separation using a flash method because the oligomer can be recovered to the product side with high efficiency.

Process (11)
In step (11), the PAS oligomer mixture obtained by the production method described in [2] above is added to the solid content (F) containing at least a PAS resin and an alkali metal halide to form at least a PAS resin and a PAS oligomer. and a mixture (G) containing an alkali metal halide.

The amount of the PAS oligomer mixture added to the solid material (F) is preferably 0.1% by mass or more, more preferably 3% by mass or more, based on the PAS resin contained in the solid material (F). Further, it is preferably 40% by mass or less, more preferably 10% by mass or less.

Process (12)
Step (12) is to wash the mixture (G) containing at least a PAS resin, a PAS oligomer, and an alkali metal halide to remove the alkali metal halide, and to remove the alkali metal halide and containing at least a PAS resin, a cyclic PAS oligomer, and a linear PAS oligomer. This is the process of obtaining mixture (H). Cleaning in this step can be performed in the same manner as in step (8). The filtered PAS resin is collected, and then it can be dried as it is and used as a PAS resin powder, or it can be further washed, separated into solid and liquid, and dried to be used as a powder or granular PAS resin. It can also be prepared.

Process (13)
Step (13) is a step of heat-treating the mixture (H) containing at least the PAS resin, cyclic PAS oligomer, and chain PAS oligomer obtained in step (12) in an oxidizing atmosphere. The heat treatment in this step can be performed in the same manner as in step (9).

<Composition/Applications, etc.>
The PAS resin obtained by the above manufacturing method may contain a mold release agent, a coloring agent, a heat stabilizer, an ultraviolet stabilizer, a foaming agent, a rust preventive, a flame retardant, a lubricant, a cup, etc., within a range that does not impair the effects of the present invention. Additives such as ring agents and fillers can be contained. As the filler, known and commonly used materials can be used as long as they do not impair the effects of the present invention. Examples include inorganic fillers. Specifically, fibrous fillers such as glass fiber, carbon fiber, silane glass fiber, ceramic fiber, aramid fiber, metal fiber, potassium titanate, silicon carbide, calcium silicate, wollastonite, natural fiber, etc. It can also be used for glass beads, glass flakes, barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, attapulgite, ferrite, calcium silicate, calcium carbonate, glass beads, zeolite, milled fiber, calcium sulfate, etc. Non-fibrous fillers can also be used.

The PAS resin obtained by the above manufacturing method may be used in combination with the following synthetic resins and elastomers, as long as the effects of the present invention are not impaired. These synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylene, polyethylene, polypropylene, polytetrafluoroethylene, Examples of the elastomer include polydifluoroethylene, polystyrene, ABS resin, epoxy resin, silicone resin, phenol resin, urethane resin, and liquid crystal polymer, and examples of the elastomer include polyolefin rubber, fluororubber, and silicone rubber.

Furthermore, the PAS resin of the present invention has excellent heat resistance, molding processability, dimensional stability, etc. by various melt processing methods such as injection molding, extrusion molding, compression molding, and blow molding. For this reason, for example, electrical and electronic parts such as connectors, printed circuit boards a, and molded seals, automotive parts such as lamp reflectors and various electrical components, interior materials for various buildings, aircraft, and automobiles, and OA equipment parts.・It can be widely used as injection molded and compression molded products such as precision parts such as camera parts and watch parts, as well as extrusion molded and pultruded molded products such as fibers, films, sheets, and pipes.

The present invention will be specifically described below with reference to Examples. These examples are illustrative and not limiting. In addition, hereinafter, unless otherwise specified, "%" and "part" are based on mass.

<Evaluation>

(1) Evaluation of the ring-opening rate of PPS oligomer The liquid phase component containing the PPS oligomer (hereinafter referred to as NMP filtrate) and the concentrate of the filtrate (hereinafter referred to as "NMP filtrate concentrate") are each added with water. was added to form a water slurry. Each water slurry was separated into solid and liquid, washed, and dried to obtain powder. 5.0000 g of the obtained powder was collected, 75 mL of chloroform was added, and the mixture was refluxed for 1 hour while heating at 65°C. The residue after extraction was treated as a chain PPS oligomer, and the solid matter contained when the obtained chloroform extract was slowly cooled to room temperature was treated as a cyclic PPS oligomer.The weight of each was measured, and NMP filtrate and NMP filtrate concentrate were determined. The PPS oligomer content in each was calculated. From the obtained value, the ring opening rate of the cyclic PPS oligomer in the NMP filtrate concentration step was calculated using the following formula. The results are shown in Tables 1 and 2.
W ₁ = Amount of cyclic PPS oligomer in 5 g of PPS oligomer contained in NMP filtrate W ₂ = Amount of cyclic PPS oligomer in 5 g of PPS oligomer contained in NMP filtrate concentrate Ring opening rate (%) = (1- W ₂ /W ₁ )×100

(2) Evaluation of melt viscosity and melt stability Using Shimadzu's flow tester "CFT-500D", 300°C, load: 20 kgf/cm ² , L/D = 10 (mm) / 1 (mm) for 6 minutes Alternatively, the melt viscosity was measured after holding for 30 minutes. The melt stability was compared based on the viscosity change rate α. The viscosity change rate α was defined as follows. When α is a smaller value, the viscosity change rate of the resin is small, indicating excellent melt stability. Further, V6 viscosity means the melt viscosity when held for 6 minutes, and V30 viscosity means the melt viscosity when held for 30 minutes. The measured values are shown in Tables 1 and 2.
α=|{(V30-V6)/V6}|×100

<Example 1>
Process (1)
19.413 kg (150 mol) of flaky sodium sulfide (60.3% by weight Na ₂ S) and N-methyl-2- 45.0 kg (454 mol) of pyrrolidone (NMP) was charged. The temperature was raised to 209° C. with stirring under a nitrogen stream, and 4.644 kg of water was distilled out (the amount of remaining water was 1.13 mol per 1 mol of sodium sulfide). Thereafter, the autoclave was sealed and cooled to 180° C., and 21.631 kg (147 mol) of p-dichlorobenzene (hereinafter abbreviated as p-DCB) and 18.0 kg (182 mol) of NMP were charged. At a liquid temperature of 150° C., the temperature was increased by increasing the pressure to 0.1 MPa using nitrogen gas. The liquid temperature was raised to 240°C over 135 minutes and held for 30 minutes. Thereafter, the liquid temperature was raised to 250° C. over 40 minutes and maintained for 73 minutes to complete the reaction. Thereafter, the autoclave was cooled.

Process (2)
The bottom valve of the autoclave was opened at 100° C., and the reaction slurry was transferred to a 150 L plate filter and filtered under pressure at 120° C., 48.0 kg of NMP was added, and the cake was washed and filtered under pressure again. The weight of the collected NMP filtrate (1) was 80.0 kg, and contained 1.09 kg of PPS oligomer (0.763 kg of cyclic oligomer, 0.328 kg of chain oligomer).

Process (3)
The NMP filtrate was charged into an evaporator with a can wall temperature of 250° C., and NMP was removed by distillation under reduced pressure of 150 mmHg to obtain 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass. The amount of cyclic oligomer in the residue was 0.534 kg, the amount of chain oligomer was 0.556 kg, and the ring opening rate of the cyclic PPS oligomer was 30.0%.

Process (5)
33.222 kg (226 mol) of p-DCB, 2.280 kg (23 mol) of NMP, and 47.23% by mass NaSH aqueous solution 27 were placed in a 150 L autoclave with stirring blades connected to a pressure gauge, thermometer, condenser, decanter, and rectification column. .300 kg (230 mol) and 18.533 kg (228 mol) of a 49.21% by mass NaOH aqueous solution were charged, and the temperature was raised to 173°C over 5 hours under a nitrogen atmosphere with stirring to distill 27.300 kg of water. After draining, the pot was sealed. p-DCB distilled azeotropically during dehydration was separated in a decanter and returned to the pot as needed. After the dehydration was completed, the anhydrous sodium sulfide composition in the form of fine particles was dispersed in the p-DCB inside the pot. After the above dehydration step was completed, the internal temperature was cooled to 160°C, 47.492 kg (479 mol) of NMP was charged, and the temperature was raised to 185°C. When the pressure reached 0.00 MPa, the valve connected to the rectification column was opened, and the internal temperature was raised to 200° C. over 1 hour. At this time, cooling and valve opening were controlled so that the temperature at the outlet of the rectifying 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 pot. The amount of distilled water was 179 g. The internal temperature was raised from 200°C to 230°C over 3 hours, stirred for 1 hour, then raised to 250°C, and stirred for 1 hour. The final pressure was 0.48 MPa.

Process (6)
After cooling to room temperature, 10.49 g of the brown residue obtained in step (3) was added to 260 g of the obtained slurry.

Process (7)
NMP contained in the slurry was distilled off under reduced pressure at 150° C. for 2 hours using a vacuum dryer.

Process (8)
After NMP distillation, 360 g of ion-exchanged water at 70°C was added to the mixture, stirred for 10 minutes, and filtered. 480 g of ion-exchanged water at 70°C was added to the cake after filtration, and the cake was washed for solid-liquid separation. (water-containing cake) was obtained. The obtained water-containing cake and 180 g of ion-exchanged water were placed in a 0.5 L autoclave and stirred at 150° C. for 30 minutes. After cooling to room temperature, it was filtered, and the filtered cake was washed with 480 g of ion-exchanged water at 70° C. to separate solid and liquid to obtain a solid component (water-containing cake). The obtained water-containing cake and 180 g of ion-exchanged water were placed in a 0.5 L autoclave, the pH was adjusted to 11.9 by adding a 48% NaOH aqueous solution, and the mixture was stirred at 200° C. for 30 minutes. After cooling to room temperature, it was filtered. The pH of the filtrate was 12.2. After filtration, 480 g of 70° C. ion-exchanged water was added to the filtered cake to wash the cake and separate the solid and liquid to obtain a solid component (water-containing cake). The obtained water-containing cake was dried at 120° C. for 4 hours to obtain 63.57 g of powder (1a). The added oligomer was 5.0% by mass based on the PPS resin.

Process (9)
Powder (1a) was heat-treated in a hot air dryer set at 250°C for 90 minutes to obtain powder (1b).

<Example 2>
Steps (1) to (3) and step (5) were performed in the same manner as in Example 1.

Process (4)
3.97 kg of ion-exchanged water at 70°C was added to the brown residue obtained in step (3) to obtain 7.75 kg of a water slurry of the residue.

Process (10)
After cooling to room temperature, NMP contained in 260 g of the obtained slurry was distilled off under reduced pressure at 150° C. for 2 hours using a vacuum dryer.

Process (11)
360 g of ion-exchanged water at 70° C. and 21.50 g of the water slurry of the residue obtained in step (4) were added to the mixture after NMP was distilled off.

Process (12)
The obtained water slurry was stirred for 10 minutes and then filtered, and the cake after filtration was washed with 480 g of ion-exchanged water at 70°C to perform solid-liquid separation to obtain a solid component (water-containing cake). The obtained water-containing cake and 180 g of ion-exchanged water were placed in a 0.5 L autoclave, and stirred at 150° C. for 30 minutes. After cooling to room temperature, it was filtered, and the filtered cake was washed with 480 g of ion-exchanged water at 70° C. to separate solid and liquid to obtain a solid component (water-containing cake). The obtained water-containing cake and 180 g of ion-exchanged water were placed in a 0.5 L autoclave, the pH was adjusted to 11.9 by adding a 48% NaOH aqueous solution, and the mixture was stirred at 200° C. for 30 minutes. After cooling to room temperature, it was filtered. The pH of the filtrate was 12.2. After filtration, 480 g of 70° C. ion-exchanged water was added to the filtered cake to wash the cake and separate the solid and liquid to obtain a solid component (water-containing cake). The obtained water-containing cake was dried at 120° C. for 4 hours to obtain 63.57 g of powder (2a). The added oligomer was 5.0% by mass based on the PPS resin.

Process (13)
Powder (2a) was heat-treated for 90 minutes in a hot air dryer set at 250°C to obtain powder (2b).

<Example 3>
Except that in step (6), the amount of brown residue added was 20.97 g, and in step (9), the powder (3a) was heat-treated for 70 minutes in a hot air dryer set at 250 ° C. The same procedure as in Example 1 was carried out to obtain 66.59 g of powder (3b). The amount of oligomer added was 10.0% by mass based on the PPS resin.

<Example 4>
Except that in step (11), the amount of residual water slurry added was 43.00 g, and in step (13) the powder (3a) was heat treated for 70 minutes in a hot air dryer set at 250 ° C. The same procedure as in Example 2 was carried out to obtain 66.59 g of powder (4b). The amount of oligomer added was 10.0% by mass based on the PPS resin.

<Example 5>
Except that in step (6), the amount of brown residue added was 41.95 g, and in step (9), the powder (5a) was heat-treated for 55 minutes in a hot air dryer set at 250 ° C. The same procedure as in Example 1 was carried out to obtain 72.65 g of powder (5b). The amount of oligomer added was 20.0% by mass based on the PPS resin.

<Example 6>
In step (11), the amount of the residual water slurry added was 85.99 g, and in step (13), the powder (6a) was heat-treated for 55 minutes in a hot air dryer set at 250 ° C. Except for the above, the same procedure as in Example 2 was carried out to obtain 72.65 g of powder (6b). The amount of oligomer added was 20.0% by mass based on the PPS resin.

<Example 7>
Steps (1), (2), (5) to (8) were carried out in the same manner as in Example 1 to obtain 63.57 g of powder (7b). In step (3), the can wall temperature was set at 270° C., and 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass was obtained. The amount of cyclic oligomer in the residue was 0.311 kg, the amount of chain oligomer was 0.780 kg, and the ring opening rate of the cyclic PPS oligomer was 59.3%. In step (9), the powder (7a) was heat-treated for 65 minutes in a hot air dryer set at 250°C. The amount of oligomer added was 5.0% by mass based on the PPS resin.

<Example 8>
Steps (1), (2), (5), (10) to (12) were carried out in the same manner as in Example 2 to obtain 63.57 g of powder (8b). In step (3), the can wall temperature was set to 270°C, and 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass was obtained. The amount of cyclic oligomer in the residue was 0.311 kg, the amount of chain oligomer was 0.780 kg, and the ring opening rate of the cyclic PPS oligomer was 59.3%. In step (13), the powder (8a) was heat-treated for 65 minutes in a hot air dryer set at 250°C. The amount of oligomer added was 5.0% by mass based on the PPS resin.

<Example 9>
Except that in step (6) the amount of brown residue added was 20.97 g, and in step (9) the powder (9a) was heat treated for 50 minutes in a hot air dryer set at 250 ° C. The same procedure as in Example 7 was carried out to obtain 66.59 g of powder (9b). The amount of oligomer added was 10.0% by mass based on the PPS resin.

<Example 10>
In step (11), the amount of the residual water slurry added was 43.00 g, and in step (13), the powder (10a) was heat-treated for 50 minutes in a hot air dryer set at 250 ° C. Except for this, the same procedure as in Example 8 was carried out to obtain 66.59 g of powder (10b). The amount of oligomer added was 10.0% by mass based on the PPS resin.

<Comparative example 1>
Steps (1), (2), (5) to (8) were carried out in the same manner as in Example 1 to obtain 63.57 g of powder (C1b). In step (3), the NMP filtrate was concentrated at a can wall temperature of 150° C. to obtain 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass. The amount of cyclic oligomer in the residue was 0.763 kg, the amount of chain oligomer was 0.328 kg, and the ring opening rate of the cyclic PPS oligomer was 0.00%. In step (9), the powder (C1a) was heat-treated for 150 minutes in a hot air dryer set at 250°C. The amount of oligomer added was 5.0% by mass based on the PPS resin.

<Comparative example 2>
In step (3), the NMP filtrate was concentrated at a can wall temperature of 150° C. to obtain 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass. The amount of cyclic oligomer in the residue was 0.763 kg, the amount of chain oligomer was 0.328 kg, and the ring opening rate of the cyclic PPS oligomer was 0.00%. Other than that, the same procedure as in Example 2 was carried out to obtain 63.57 g of powder (C2a), and the amount of oligomer added was 5.0% by mass based on the PPS resin. The melt viscosity (V6) of the obtained powder (C2a) was 39 Pa·s. In step (13), the powder (C2a) was heat-treated for 150 minutes in a hot air dryer set at 250°C. The k of the powder (C2a) was 1.9. The powder (C2b) obtained after the heat treatment had a melt viscosity of 181 Pa·s and a viscosity change rate of 15.5%.

<Comparative example 3>
Comparison except that in step (6), the amount of brown residue added was 20.97 g, and in step (9), the powder (C3a) was heat-treated for 170 minutes in a hot air dryer set at 250 ° C. The same procedure as in Example 1 was carried out to obtain 66.59 g of powder (C3b). The amount of oligomer added was 10.0% by mass based on the PPS resin.

<Comparative example 4>
Except that in step (6), the amount of brown residue added was 41.95 g, and in step (9), the powder (C4a) was heat-treated for 170 minutes in a hot air dryer set at 250 ° C. The same procedure as in Comparative Example 1 was carried out to obtain 72.65 g of powder (C4a). The amount of oligomer added was 20.0% by mass based on the PPS resin.

<Comparative example 5>
In step (3), the NMP filtrate was concentrated at a can wall temperature of 210° C. and under normal pressure. 3.78 kg of a brown solid residue with a nonvolatile content of 45% by mass was obtained, the amount of cyclic oligomer in the residue was 0.760 kg, the amount of chain oligomer was 0.331 kg, and the ring opening rate of the cyclic PPS oligomer was 0.39%. Met. In step (9), the powder (C5a) was heat-treated for 150 minutes in a hot air dryer set at 250°C. Other than that, the same procedure as in Example 1 was carried out to obtain 63.57 g of powder (C5b). The amount of oligomer added was 5.0% by mass based on the PPS resin.

<Reference example 1>
Steps (1) to (4) were not performed, and only steps (5) to (9) were performed in the same manner as in Example 1. In step (9), the powder (R1a) was dried in a hot air dryer set at 250°C. Heat treatment was performed for 180 minutes. 60.54 g of powder (R1b) with an oligomer addition rate of 0.00% was obtained.

From the results in Tables 1 and 2, it was shown that the crosslinking rate of the examples was increased due to the short heat treatment time, and the viscosity change rate of the obtained resin was small, compared to the comparative examples. Therefore, it was confirmed that PAS oligomers can be recovered with high efficiency and a crosslinked PPS resin having excellent thermal stability can be obtained.

Claims (4)

At least a polyarylene sulfide resin is produced by 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 step (1) of obtaining a crude reaction mixture containing a cyclic polyarylene sulfide oligomer, a linear polyarylene sulfide oligomer, an alkali metal halide, and an organic polar solvent;
Step (2) of removing the solid phase component from the crude reaction mixture by solid-liquid separation to obtain a liquid phase component (A) containing at least a cyclic polyarylene sulfide oligomer and a chain polyarylene sulfide oligomer;
A step of supplying the liquid phase component (A) into an evaporator and concentrating the liquid phase component (A) at 230° C. to 280° C. in a reduced pressure or normal pressure environment to obtain a polyarylene sulfide oligomer mixture (B). (3), and
A method for producing a polyarylene sulfide oligomer mixture, characterized in that in step (3), the ring opening rate of the cyclic polyarylene sulfide oligomer upon concentration is 10% or more. The method for producing a polyarylene sulfide oligomer mixture according to claim 1, further comprising a step (4) of bringing the oligomer mixture (B) into contact with water to form a slurry. At least a polyarylene sulfide resin is produced by 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 step (5) of obtaining a crude reaction mixture containing an alkali metal halide and an organic polar solvent;
The polyarylene sulfide oligomer mixture obtained by the production method according to claim 1 is added to the crude reaction mixture to prepare at least a polyarylene sulfide resin, a cyclic polyarylene sulfide oligomer, a chain polyarylene sulfide oligomer, and an alkali metal halide. and a step (6) of obtaining a mixture (C) containing an organic polar solvent;
A step (7) of solid-liquid separation of the mixture (C) by a flash method to obtain a mixture (D) containing at least a polyarylene sulfide resin, a cyclic polyarylene sulfide oligomer, a chain polyarylene sulfide oligomer, and an alkali metal halide;
A step (8) of washing the mixture (D) to remove the alkali metal halide to obtain a mixture (E) containing at least a polyarylene sulfide resin, a cyclic polyarylene sulfide oligomer, and a chain polyarylene sulfide oligomer, and A method for producing a crosslinked polyarylene sulfide resin, comprising a step (9) of heat-treating the mixture (E) in an oxidizing atmosphere. At least a polyarylene sulfide resin is produced by 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 step (5) of obtaining a crude reaction mixture containing an alkali metal halide and an organic polar solvent;
solid-liquid separation of the crude reaction mixture by a flash method to obtain a solid content (F) containing at least a polyarylene sulfide resin and an alkali metal halide (10);
The polyarylene sulfide oligomer mixture obtained by the production method according to claim 2 is added to the solid content (F) to produce at least a polyarylene sulfide resin, a cyclic polyarylene sulfide oligomer, a chain polyarylene sulfide oligomer, and Step (11) of obtaining a mixture (G) containing an alkali metal halide;
a step (12) of washing the mixture (G) to remove the alkali metal halide to obtain a mixture (H) containing at least a polyarylene sulfide resin, a cyclic polyarylene sulfide oligomer, and a chain polyarylene sulfide oligomer; A method for producing a crosslinked polyarylene sulfide resin, comprising a step (13) of heat-treating the mixture (H) in an oxidizing atmosphere.