JP5422988B2 - Process for producing polyarylene sulfide - Google Patents

Description

  The present invention relates to a method for producing polyarylene sulfide. More particularly, the present invention relates to a method for producing a high-quality polyarylene sulfide having a reduced metal content and oligomer component.

  Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) represented by polyphenylene sulfide (hereinafter also abbreviated as PPS) has excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties, heat and humidity resistance, It is a resin having properties suitable as an engineering plastic such as flame retardancy. Also, it can be molded into various molded parts, films, sheets, fibers, etc. by injection molding and extrusion molding, and widely used in fields requiring heat resistance and chemical resistance such as various electric / electronic parts, mechanical parts, and automotive parts. It has been.

  As a specific method for producing this PAS, a method of reacting an alkali metal sulfide such as sodium sulfide with a polyhaloaromatic compound such as p-dichlorobenzene in an organic amide solvent such as N-methyl-2-pyrrolidone is proposed. This method is widely used as an industrial production method for PAS. Since the polymerization reaction in this production method is a desalting polycondensation mechanism, a large amount of by-product salt such as sodium chloride is generated. Therefore, a by-product salt removal step is required after the polymerization reaction, but it is difficult to completely remove the by-product salt by ordinary treatment, and in general commercial PPS products, the alkali metal content is about several thousand ppm. Contained. Thus, when the alkali metal salt remains in the produced polymer, there arises a problem that physical properties such as electrical characteristics are lowered. Therefore, when an attempt is made to apply a molded article using such polyarylene sulfide as a raw material to the field of electric / electronic parts, the deterioration of the electric characteristics due to the alkali metal in the polyarylene sulfide becomes a major obstacle. Furthermore, in this production method, not a little oligoarylene sulfide, which is a PAS component having a low molecular weight, is produced in the polymerization reaction stage of PAS, but in the usual PAS recovery method, this oligoarylene sulfide is recovered together with PAS, and the physical properties of PAS It also included the problem of adversely affecting the environment.

  The above-mentioned problems in PAS, that is, methods for reducing the amount of metal contained in PAS have been variously studied so far. For example, PPS containing 1000 ppm or more of alkali metal obtained by the above method is heated at 120 ° C. or less for a long time. A method of repeatedly carrying out water washing (see, for example, Patent Document 2), a reaction product containing PPS obtained by reacting sodium hydrosulfide, sodium hydroxide and p-dichlorobenzene in N-methyl-pyrrolidone is mixed with water and A method of repeatedly washing with warm water, followed by washing with an acidic aqueous solution followed by washing with ion-exchanged water (see, for example, Patent Document 3), and a method of repeatedly washing PPS in the presence of a surfactant (see, for example, Patent Document 4). Etc.) are disclosed. Regarding the removal of the metal compound (by-product salt) generated in the reaction generation stage of PAS, in these methods, a mixture containing solid PAS and the metal compound is brought into contact with water, and the metal compound is dissolved in water to dissolve it from the PAS. Since the removal method is adopted, several steps of long-time water washing using a large amount of water are necessary to remove the metal impurities, and thus a very large and complicated process is necessary. Furthermore, it is necessary to treat a large amount of aqueous waste liquid generated in this washing process, which is a process with extremely high process cost and environmental load. In addition, since oligoarylene sulfides generated in the polymerization reaction stage of PAS are hydrophobic compounds, oligoarylene sulfides are separated from polyarylene sulfides by the method of removing metal compounds by washing with water as described above to reduce the metal content. However, the polyarylene sulfide obtained by these methods has a fundamental problem that it contains most of the oligoarylene sulfide produced in the polymerization reaction stage.

  Methods for separating polyarylene sulfide and oligoarylene sulfide to obtain polyarylene sulfide with reduced oligoarylene sulfide include a method of washing PAS with an organic solvent (see, for example, Patent Document 5), a polymerization solvent under reduced pressure, and the like. And methods for removing low molecular weight substances (for example, see Patent Documents 6 and 7). Since these methods employ a method of promoting the removal of low molecular weight substances, it is expected that a PAS having a reduced low molecular weight compound can be obtained compared to the above-described method. However, it is difficult to say that these methods are still at a sufficient level in view of producing a higher quality PAS which has been craved in recent years, and in these methods, solid PAS containing a large amount of metal components Since the metal component is separated from the metal, it is an insufficient method for reducing the amount of metal impurities in PAS, which is another problem.

  Further, as a method for achieving both reduction of metal content and reduction of oligoarylene sulfide which is a low molecular weight component, for example, a method of bringing a PPS resin into contact with a mixed solvent containing a polar aprotic solvent and ethylene glycol (for example, Patent Document 8). ), A method in which polyarylene sulfide particles are washed with an organic solvent having a boiling point lower than that of water and compatible with water (see, for example, Patent Document 9), polyphenylene sulfide with water and a hydrophobic organic solvent. A method for purification using a mixed solvent (see, for example, Patent Document 10) is disclosed. However, since these methods are a method of treating a mixture containing PAS, oligoarylene sulfide and a large amount of metal components with an organic solvent, multistage, long-time treatment is required to sufficiently reduce the metal components. In addition, the obtained PAS has not reached satisfactory characteristics.

On the other hand, as a simple method for separating the metal component from the PAS component, for example, the reaction solution generated after polymerization in the production of polyphenylene sulfide is filtered through a pressure filter at a temperature higher than 180 ° C., and then the filtrate is introduced into water or a water-containing medium. A method of recovering the polyarylene sulfide component by precipitating (see, for example, Patent Document 11), and in the process of producing the polysulfide arylene, the polysulfide arylene and the sub-arylene are adsorbed at a temperature at which the polysulfide arylene is dissolved in the reaction solvent. By separating the resulting metal salt from the solution, a solution containing polysulfide arylene is recovered, and after removing the solvent from the solution and isolating the polysulfide arylene, the polysulfide arylene in the molten state is mixed with water. After contacting multiple times, polysulfide arylene is isolated through vacuum extrusion and other techniques. Method (see, for example, Patent Document 12), sodium chloride monomer and dichlorobenzene monomer are polymerized in N-methyl-2-pyrrolidone, and then sodium chloride formed by polymerization is separated at a temperature higher than 180 ° C., and then 15 MPa or more A method for recovering polyarylene sulfide by adding carbon dioxide until a high pressure state is obtained is disclosed (for example, see Patent Document 13). In these methods, since solid-liquid separation is performed in a state in which most or all of the PAS components are dissolved, sodium chloride, which is a metal component, is separated from the PAS, so that a PAS with a reduced metal content can be obtained. I can expect that. However, in these methods, since the PAS is recovered by bringing the solution containing PAS obtained after separating the metal component into contact with water, which is a poor solvent, the oligoarylene sulfide that is a hydrophobic compound is also recovered together with the PAS. In addition, there are still many problems to be solved, such as the need for a special and expensive process because processing at extremely high pressure is essential.
Japanese Patent Publication No. 45-3368 JP-A-55-156342 JP-A-61-220446 Japanese Patent Laid-Open No. 62-185718 JP 59-6221 A JP 59-89327 A Japanese Patent Laid-Open No. 5-125186 JP-A-57-108135 Japanese Patent Laid-Open No. 4-139215 JP-A-62-220522 JP-A-62-86022 JP-A-4-318027 JP-A-10-265576

  An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing a high-quality polyarylene sulfide having a reduced metal content and oligomer component.

In response to the above problems, the present invention
1. A polyarylene sulfide having a weight average molecular weight of 5,000 to 1,000,000 and a weight average molecular weight of 200 to 200 , which is obtained by bringing a sulfidizing agent and a dihalogenated aromatic compound into contact with each other in an organic polar solvent. 2,500 oligo arylene sulfide to a method of recovering the polyarylene sulfide from the reaction mixture containing the alkali metal halide and an organic polar solvent, at a temperature sufficient to dissolve the polyarylene sulfide (a) in the reaction mixture the polyarylene sulfide by punished the reaction mixture at some 230 ° C. or higher in the first solid-liquid separation to obtain a filtrate component containing the oligo arylene sulfide and organic polar solvent, (b) then, the poly said filtrate component The filtrate is adjusted to a temperature at which the arylene sulfide does not dissolve. The method of manufacturing polyarylene sulfide, wherein the punished minute to second solid-liquid separation,
2. The method for producing polyarylene sulfide according to 1, wherein the temperature at which the first solid-liquid separation is performed is 235 ° C or higher ,
3. The method for producing polyarylene sulfide according to either 1 or 2, wherein the temperature at which the second solid-liquid separation is performed is 200 ° C or lower,
4). The method for producing polyarylene sulfide according to any one of 1 to 3, wherein the temperature at which the second solid-liquid separation is performed is 150 ° C or lower,
5. The method for producing polyarylene sulfide according to any one of 1 to 4, wherein the solid content is precipitated by centrifugation before performing the first solid-liquid separation and / or the second solid-liquid separation,
6). The method for producing polyarylene sulfide according to any one of 1 to 5, wherein 90% or more of the alkali metal halide in the reaction mixture is separated as a solid content by the first solid-liquid separation,
7). The method for producing polyarylene sulfide according to any one of 1 to 6, wherein the pressure during the first and second solid-liquid separation is 1.0 MPa or less,
8). The method for producing polyarylene sulfide according to any one of 1 to 7, wherein the organic polar solvent is an organic amide solvent,
9. The method for producing polyarylene sulfide according to any one of 1 to 8, wherein the dihalogenated aromatic compound is dichlorobenzene.

  The present invention can provide a method for producing a high-quality polyarylene sulfide having a reduced metal content and oligomer component.

  Embodiments of the present invention will be described below.

(1) Sulfiding agent The sulfiding agent used in the present invention may be any sulfidizing agent as long as it can introduce a sulfide bond into a dihalogenated aromatic compound. Examples thereof include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide. It is done.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more thereof, among which lithium sulfide and / or sodium sulfide are preferable. Sodium sulfide is more preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides. The aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Since generally available inexpensive alkali metal sulfides are hydrates or aqueous mixtures, it is preferred to use such forms of alkali metal sulfides.

  Specific examples of the alkali metal hydrosulfide include, for example, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more thereof. Lithium hydrosulfide and / or sodium hydrosulfide are preferable, and sodium hydrosulfide is more preferably used.

  In addition, an alkali metal sulfide prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alternatively, an alkali metal sulfide prepared by previously contacting an alkali metal hydrosulfide and an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used as hydrates or aqueous mixtures, or in the form of anhydrides. From the viewpoint of availability and cost of hydrates or aqueous mixtures. preferable.

  Furthermore, alkali metal sulfides prepared in situ in the reaction system from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide can also be used. Further, alkali metal sulfides prepared by previously contacting alkali metal hydroxides such as lithium hydroxide and sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide can be used in any form of gas, liquid, and aqueous solution.

  In the present invention, the amount of the sulfidizing agent is the remaining amount obtained by subtracting the amount of loss from the actual charge amount when a partial loss of the sulfidizing agent occurs before the reaction with the dihalogenated aromatic compound due to dehydration operation or the like. It shall mean quantity.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and a mixture of two or more thereof. Specific examples of the metal hydroxide include, for example, calcium hydroxide, strontium hydroxide, barium hydroxide, and sodium hydroxide is preferably used.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time, but the amount used is 0.95 to 1. A range of 50 moles, preferably 1.00 to 1.25 moles, more preferably 1.005 to 1.200 moles can be exemplified. When hydrogen sulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. The amount of the alkali metal hydroxide used in this case is 2.0 to 3.0 with respect to 1 mole of hydrogen sulfide. The range of mol, Preferably it is 2.01-2.50 mol, More preferably, it is 2.04-2.40 mol.

(2) Dihalogenated aromatic compound Examples of the dihalogenated aromatic compound used in the present invention include p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, Dihalogenated benzene such as 1-bromo-4-chlorobenzene, 1-bromo-3-chlorobenzene, and 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl- Examples thereof include dihalogenated aromatic compounds containing substituents other than halogen such as 2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, and 3,5-dichlorobenzoic acid. Especially, the dihalogenated aromatic compound which has p-dihalogenated benzene represented by p-dichlorobenzene as a main component is preferable. Particularly preferably, it contains 80 to 100 mol%, more preferably 90 to 100 mol% of p-dichlorobenzene. It is also possible to use a combination of two or more different dihalogenated aromatic compounds in order to produce a copolymer.

  The amount of the dihalogenated aromatic compound used is preferably in the range of 0.9 to 2.0 mol, more preferably in the range of 0.95 to 1.5 mol, per mol of the sulfur component of the sulfiding agent. The range of .98 to 1.2 mol is more preferable.

(3) Organic polar solvent In the present invention, an organic polar solvent is used as a reaction solvent when the sulfidizing agent and the dihalogenated aromatic compound are brought into contact with each other, and among them, an organic amide solvent is preferably used. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and N-cyclohexyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, An aprotic organic solvent typified by 3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, etc., and a mixture thereof, have a stable reaction. It is preferably used because it is expensive. Among these, N-methyl-2-pyrrolidone and / or 1,3-dimethyl-2-imidazolidinone are preferable, and N-methyl-2-pyrrolidone is particularly preferably used.

  The amount of the organic polar solvent used in the present invention is not particularly limited, and the amount used is changed in order to obtain the desired characteristics of PAS and oligoarylene sulfide produced by the reaction of the sulfidizing agent with the dihalogenated aromatic compound. It can be made. In general, when high molecular weight PAS is desired, it is advantageous to reduce the amount of organic polar solvent used, and the amount of organic polar solvent used should be less than 1.25 L per mole of sulfur component of the sulfiding agent. Can be illustrated. On the other hand, when a low molecular weight PAS is desired or when it is desired to increase the amount of oligoarylene sulfide produced, it is also preferable to use an organic polar solvent in an amount of 1.25 L or more per mole of sulfur component of the sulfiding agent. is there. In addition, although there is no restriction | limiting in particular in the upper limit of the amount of organic polar solvents used, From a viewpoint of making a sulfidizing agent and a dihalo aromatic compound react more efficiently, it is 50 liters or less with respect to 1 mol of sulfur components of a sulfidizing agent. Preferably, it is 20 liters or less, more preferably 15 liters or less. With such a preferable amount of the organic polar solvent used, the reaction between the sulfidizing agent and the dihalogenated aromatic compound can proceed in a short time with good yield. Here, the amount of solvent used is based on the volume of the solvent under normal temperature and pressure. Moreover, the usage-amount of an organic polar solvent is the quantity which deducted the organic polar solvent removed out of the reaction system from the organic polar solvent introduce | transduced in the reaction system.

(4) Polymerization aid In the present invention, it is also possible to use a polymerization aid when a PAS having a particularly high molecular weight is desired, or in order to carry out the reaction in a shorter time. Specific examples of the polymerization aid are not particularly limited as long as they are generally known as polymerization aids for PAS, and examples thereof include alkali metal carboxylates, water, and lithium halides. Particularly preferred are alkali metal carboxylates.

  The alkali metal carboxylate is represented by the general formula R (COOM) n (wherein R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group. , Lithium, sodium, potassium, rubidium and cesium, and n is an integer of 1 to 3). Alkali metal carboxylates can also be used as anhydrous, hydrated or aqueous solutions. Specific examples of the alkali metal carboxylate include, for example, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. Can be mentioned. Alkali metal carboxylate is an organic acid, an organic acid, and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, with approximately equal chemical equivalents. You may form by adding and making it react one by one. Among the alkali metal carboxylates, sodium acetate is particularly preferably used because it is inexpensive and easily available.

  The amount of the polymerization aid used is not particularly limited as long as it does not significantly adversely affect the reaction between the sulfidizing agent and the dihalogenated aromatic compound, but it is 0 per mol of the sulfur component of the sulfidizing agent. A range of 0.01 mole to 5 moles may be employed.

(5) Polymerization stabilizer In the present invention, a polymerization stabilizer can also be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilization of the polymerization reaction system and suppresses undesirable side reactions. One measure of the side reaction is the generation of thiophenol, and the addition of a polymerization stabilizer tends to suppress the generation of thiophenol. Specific examples of the polymerization stabilizer include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferable. Since the alkali metal carboxylate described above also acts as a polymerization stabilizer, it is one of the polymerization stabilizers used in the present invention.

  These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is usually 0.01 to 5.0 mol, preferably 0.02 to 1.0 mol, more preferably 0.03 to 0.5 mol, per 1 mol of the sulfur component of the sulfidizing agent. Use as a percentage. If this ratio is small, the stabilizing effect is insufficient. Conversely, if it is too large, it is economically disadvantageous or the yield of the PAS component tends to decrease. There is no particular limitation on the addition timing of the polymerization stabilizer, and any time before the start of polymerization, at the time from the start of polymerization to the middle of the polymerization, or any combination thereof is adopted.

(6) Molecular weight regulator / branching / crosslinking agent In the present invention, a molecular weight regulator such as a monohalogen compound (not necessarily an aromatic compound) is used to form a terminal of PAS or to regulate a polymerization reaction or a molecular weight. May be used in combination with the dihalogenated aromatic compound. In order to form a branched or cross-linked polymer, branching such as trihalogenated polyhalogen compounds (not necessarily aromatic compounds), active hydrogen-containing halogenated aromatic compounds, and halogenated aromatic nitro compounds. -A cross-linking agent can be used in combination. As the polyhalogen compound, a commonly used compound can be used. Among them, polyhalogenated aromatic compounds are preferable, and specific examples include 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, Examples include 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 1,4,6-trichloronaphthalene, and among them, 1,3,5-trichlorobenzene and 1,2,4-trichlorobenzene are preferable. Examples of the active hydrogen-containing halogenated aromatic compound include halogenated aromatic compounds having functional groups such as amino group, mercapto group, and hydroxyl group. Specific examples include 2,5-dichloroaniline, 2,4-dichloroaniline, 2,3-dichloroaniline, 2,4,6-trichloroaniline, 2,2′-diamino-4,4′-dichlorodiphenyl ether, 2 , 4′-diamino-2 ′, 4-dichlorodiphenyl ether, and the like. Examples of the halogenated aromatic nitro compound include 2,4-dinitrochlorobenzene, 2,5-dichloronitrobenzene, 2-nitro-4,4′-dichlorodiphenyl ether, and 3,3′-dinitro-4,4′-. Examples include dichlorodiphenyl sulfone, 2,5-dichloro-2-nitropyridine, 2-chloro-3,5-dinitropyridine, and the like.

(7) Reaction of sulfidizing agent and dihalogenated aromatic compound In the production of the polyarylene sulfide of the present invention, the sulfidizing agent and the dihalogenated aromatic compound are brought into contact with each other in an organic polar solvent and reacted. The polyarylene sulfide is recovered from the reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent.

  Here, the method of bringing the sulfidizing agent and dihalogenated aromatic compound into contact with each other in an organic polar solvent is a reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent as raw materials. There is no particular limitation as long as it can be obtained, and a known method can be adopted. As this method, for example, a mixture of the above raw materials is usually heated to a temperature of 120 to 300 ° C., preferably 180 to 280 ° C. for 0.1 to 40 hours, preferably 0.5 to 20 hours, more preferably It is preferable that the reaction is carried out by heating for 1 to 10 hours. In such a temperature range, the reaction tends to proceed in a short time, and the reaction tends to proceed uniformly and easily. The reaction may be either a one-step reaction performed at a constant temperature, a multi-step reaction in which the temperature is raised stepwise, or a reaction in which the temperature is continuously changed. In order to suppress it, after carrying out some reaction at 120-240 degreeC, the method of superposing | polymerizing at 240-300 degreeC can also be illustrated as a preferable method. In addition, the reaction time depends on the type and amount of the raw material used or the reaction temperature, and thus cannot be defined unconditionally. However, the amount of unreacted components can be sufficiently reduced within the above time range, so that the polyarylene as the target product can be reduced. The sulfide component tends to be recovered with good yield and efficiency.

  In the reaction of the sulfidizing agent of the present invention with a dihalogenated aromatic compound, an organic polar solvent, a dihalogenated aromatic compound, and a sulfidizing agent are charged into the reactor, and sufficiently stirred and mixed in the reactor. A method of polymerizing at a polymerization temperature; an organic polar solvent and a sulfidizing agent are charged into the reactor, and the reactor is sufficiently stirred and mixed; then, the temperature is raised to the polymerization temperature and then dihalogenated aromatic A method in which a compound is added and reacted; an organic polar solvent and a dihalogenated aromatic compound are charged in a reactor, sufficiently stirred in the reactor, heated to a polymerization temperature, and then a sulfidizing agent solid or slurry (water or (Depending on the solvent) and polymerizing by adding an organic polar solvent, a sulfidizing agent, and a dihalogenated aromatic compound to a reactor preliminarily adjusted to the reaction temperature. Etc. can be exemplified method of.

The amount of water in the reaction system is the amount of sulfur present in the reaction system at the start of the reaction, that is, when the conversion rate of the dihalogenated aromatic compound (hereinafter sometimes abbreviated as DHA) charged to the reaction system is zero. The amount is preferably 0.1 mol or more and 10 mol or less per mol of the component, and with such a water content, the reaction proceeds in a shorter time, and the progress of an undesirable side reaction tends to be reduced. Therefore, when the raw materials and other components used in the reaction contain water, each component is dehydrated before the reaction, or the reaction system is dehydrated after mixing the water-containing components. It is preferable to adjust the water content. In addition, when the amount of water in the reaction system is small, water can be added. It is also possible to add water to the reaction system during the reaction, but until the DHA conversion is 30% or more, preferably 50% or more, more preferably 70% or more, and even more preferably 80% or more. The water content in the reaction system is preferably from 0.1 to 10 mol per mol of sulfur component present in the reaction system. The DHA conversion rate is a value calculated by the following equation. The remaining amount of DHA can be usually determined by gas chromatography.
(A) When the dihalogenated aromatic compound is added in excess in a molar ratio with respect to the sulfidizing agent: Conversion = [[DHA charge (mol) -DHA remaining amount (mol)] / [DHA charge (mol)- DHA excess (mole)]] × 100%
(B) In cases other than the above (a) Conversion rate = [[DHA charge (mol) −DHA remaining amount (mol)] / [DHA charge (mol)]] × 100%

  Further, in the reaction of the sulfidizing agent of the present invention with a dihalogenated aromatic compound, the entire reaction step is carried out for the purpose of allowing the reaction to proceed in a shorter time and improving the molecular weight of the polyarylene sulfide produced by the reaction. It is also possible to carry out at least a part of them in the presence of the aforementioned polymerization aid, preferably in the presence of an alkali metal carboxylate. There are no particular restrictions on the timing of addition of the polymerization aid, and it may be added before the start of the reaction, at the start of the reaction, or at any point during the reaction, or may be added in multiple portions. The alkali metal carboxylate may be added in any form such as an anhydride, a hydrate, an aqueous solution or a mixture with an organic polar solvent, and the alkali metal carboxylate to be added contains water, and When the DHA conversion is not more than 80%, preferably not more than 70%, more preferably not more than 50%, still more preferably not more than 30%, the addition of the alkali metal carboxylate in the reaction system It is preferable that the water content be 0.1 to 10 moles per mole of sulfur component present in the reaction system.

  For this reaction, usual polymerization methods such as a batch method and a continuous method can be employed. The atmosphere in which the reaction is performed is preferably a non-oxidizing atmosphere, and is preferably performed in an inert gas atmosphere such as nitrogen, helium, or argon. Nitrogen is particularly preferable from the viewpoint of economy and ease of handling.

  The reaction pressure is not particularly limited because it cannot be defined unconditionally depending on the type and amount of the raw material and solvent used, or the reaction temperature.

(8) Polyarylene sulfide The polyarylene sulfide in the present invention is a homopolymer or copolymer having a repeating unit of the formula: — (Ar—S) — as the main constituent unit, preferably containing 80 mol% or more of the repeating unit. Thus, the structure is preferably linear. Ar includes units represented by the following formulas (A) to (L), among which the formula (A) is particularly preferable.

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same or different. May be good.)

  As long as this repeating unit is a main structural unit, it can contain a small amount of branching units or crosslinking units represented by the following formulas (M) to (P). The amount of copolymerization of these branched units or cross-linked units is preferably in the range of 0 to 1 mol% with respect to 1 mol of-(Ar-S)-units.

  The PAS in the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the above repeating unit. Typical examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers, and mixtures thereof. Particularly preferred PASs include p-phenylene sulfide units as the main structural unit of the polymer.

In addition to polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) containing 80 mol% or more, particularly 90 mol% or more, polyphenylene sulfide sulfone and polyphenylene sulfide ketone.

  Although there is no restriction | limiting in particular in the melt viscosity of various PAS in this invention, As a melt viscosity of general PAS, the range of 0.1-1000 Pa.s (300 degreeC, shear rate 1000 / sec) can be illustrated, 0.1 It can be said that the range of ˜500 Pa · s is a preferable range from the viewpoint of excellent workability during molding. The molecular weight of PAS is not particularly limited, but examples of the weight average molecular weight of general PAS include 2,000 to 1,000,000, preferably 2,500 to 500,000, and preferably 5,000 to 100,000 is more preferred. In general, a PAS having a weight average molecular weight in the above range is particularly excellent in properties such as mechanical strength and chemical resistance. Also, under the conditions for performing the separation operation of PAS and oligoarylene sulfide, which will be described later, such a PAS tends to exist as a solid in an organic polar solvent, so that the separation property from oligoarylene sulfide tends to be remarkably improved. Therefore, it can be said to be particularly suitable in the present invention.

(9) Oligoarylene sulfide The oligoarylene sulfide in the present invention is a homopolymer or copolymer having a repeating unit of the formula:-(Ar-S)-as the main constituent unit, preferably containing 80 mol% or more of the repeating unit. . Ar includes units represented by the above formulas (A) to (L), among which the formula (A) is particularly preferable.

  In addition, the oligoarylene sulfide in the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the repeating unit. Typical examples of these include oligophenylene sulfide, oligophenylene sulfide sulfone, oligophenylene sulfide ketone, random copolymers thereof, block copolymers, and mixtures thereof. Particularly preferred oligoarylene sulfides include oligopolyphenylene sulfide sulfones and oligophenylene sulfide ketones in addition to oligophenylene sulfides containing 80 mol% or more, particularly 90 mol% or more of p-phenylene sulfide units as main structural units.

  The average molecular weight of various oligoarylene sulfides in the present invention can be defined as lower than the above-mentioned PAS, and the weight average molecular weight of a general oligoarylene sulfide can be exemplified by 200 to 5,000, preferably 200 to 2,500. 300 to 2,000 is more preferable. As a result of detailed examination of the difference in properties between PAS and oligoarylene sulfide, the inventors of the present invention have a tendency for oligoarylene sulfide having a weight average molecular weight in the above-mentioned range to be more soluble in various solvents than the aforementioned PAS. I found out. In particular, it has been found that oligoarylene sulfide has high solubility in an organic polar solvent, and in this respect, the characteristics are greatly different from those of the aforementioned PAS. That is, PAS is likely to be present as a solid in an organic polar solvent under the conditions for separating PAS and oligoarylene sulfide, which will be described later. On the other hand, oligoarylene sulfide is easily dissolved in an organic polar solvent. The present inventors have found that PAS and oligoarylene sulfide can be separated with good separability by liquid separation operation, and the present invention has been completed. From this viewpoint, in the present invention, it can be said that the above range is particularly suitable for the weight molecular weight of the oligoarylene sulfide.

  Moreover, there is no restriction | limiting in particular in the structure of the oligoarylene sulfide of this invention, Various structures, such as a linear structure, a branched structure, a graft structure, and a cyclic structure, and mixtures thereof are accept | permitted. Among these, linear and / or cyclic oligoarylene sulfides are preferable, and there is an advantage that a strict reaction control and a third component for introducing a branched structure are not required to obtain these structures.

  Herein, the oligoarylene sulfide cyclic body in the present invention (hereinafter sometimes referred to as a cyclic oligoarylene sulfide) is a cyclic compound having a repeating unit of formula, — (Ar—S) — as a main structural unit. Preferably, it is a compound such as the following general formula (Q) containing 80 mol% or more of the repeating unit.

  Here, examples of Ar can include units represented by the formulas (A) to (L), among which the formulas (A) to (C) are preferable, and the formulas (A) and (B) are more preferable. Formula (A) is particularly preferable.

  In addition, in cyclic oligoarylene sulfide, repeating units, such as said Formula (A)-Formula (L), may be included at random, may be included in a block, and any of those mixtures may be sufficient. Typical examples of these include cyclic oligophenylene sulfide, cyclic oligophenylene sulfide sulfone, cyclic oligophenylene sulfide ketone, cyclic random copolymers containing these, cyclic block copolymers, and mixtures thereof. Is mentioned. Particularly preferred cyclic oligoarylene sulfides include cyclic oligophenylene sulfides (hereinafter sometimes abbreviated as cyclic PPS) containing 80 mol% or more, particularly 90 mol% or more of p-phenylene sulfide units as main structural units. Can be mentioned.

  Although there is no restriction | limiting in particular in the repeating number m in the said (Q) formula of cyclic oligoarylene sulfide, 2-50 are preferable, 2-25 are more preferable, and 3-20 can be illustrated as a still more preferable range. The use of cyclic oligoarylene sulfide can be exemplified by the use of a mixture containing cyclic oligoarylene sulfide that is converted to a high degree of polymerization by heating, and when used in such applications, cyclic oligoarylene sulfide is used. It is preferable to carry out the heating at a temperature higher than the temperature at which the sulfide melts, but when m increases, the melting temperature of the cyclic oligoarylene sulfide tends to increase. Therefore, when cyclic oligoarylene sulfide is used for such applications, it is advantageous to set m in the above range from the viewpoint that the melt solution of cyclic oligoarylene sulfide is possible at a lower temperature.

  The cyclic oligoarylene sulfide may be either a single compound having a single repeating number or a mixture of cyclic oligoarylene sulfides having different repeating numbers, but it may be a mixture of cyclic oligoarylene sulfides having different repeating numbers. The melt solution temperature tends to be lower than that of a single compound having a single number of repetitions, and the use of a mixture of cyclic oligoarylene sulfides having different numbers of repetitions is used in the conversion to the above-mentioned high degree of polymerization. This is preferable because the temperature can be lowered.

(10) Alkali metal halide The alkali metal halide in the present invention is produced by the reaction of a sulfidizing agent and a dihalogenated aromatic compound, produced by reaction of other components in the reaction system, sulfide It includes all alkali metal halides present in the reaction mixture, such as alkali metal halides introduced into the reaction system at an optional stage such as before the start of the reaction between the agent and the dihalogenated aromatic compound, during the reaction, and after the reaction. Alkali metal halides include any combination of alkali metals, i.e. lithium, sodium, potassium, rubidium and cesium, and halogens, i.e. fluorine, chlorine, bromine, iodine and astatine. Examples include lithium, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide, lithium iodide, sodium iodide, potassium iodide, cesium fluoride, and the like. The alkali metal halide produced by the reaction of the sulfidizing agent and the dihalogenated aromatic compound is composed of the alkali metal contained in the sulfidizing agent and the halogen contained in the dihalide. Examples of alkali metal halides resulting from a combination of an agent and a dihalogenated aromatic compound include lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide and sodium iodide. Sodium chloride, potassium chloride Sodium bromide and potassium bromide can be exemplified as preferable examples, and sodium chloride is more preferable. As a result of detailed examination of the characteristics of these preferred alkali metal halides, the present inventors have found that the solubility in the aforementioned organic polar solvent is low and the temperature dependence of the solubility is small. Therefore, it tends to be easily separated from the reaction mixture by the first solid-liquid separation described later, and it can be said that it is particularly preferable from this viewpoint.

(11) Recovery of polyarylene sulfide and oligoarylene sulfide from reaction mixture In the present invention, a reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent is used. (A) Polyarylene in the reaction mixture A filtrate component containing polyarylene sulfide, oligoarylene sulfide and an organic polar solvent is obtained by subjecting the reaction mixture to a first solid-liquid separation at a temperature sufficient to dissolve sulfide, and (b) The filtrate component is subjected to a second solid-liquid separation after the temperature at which the arylene sulfide does not dissolve is set. Hereinafter, the first solid-liquid separation and the second solid-liquid separation will be described in detail.

(A) First solid-liquid separation In the first solid-liquid separation, a solid component and a soluble component existing in the reaction mixture, that is, polyarylene sulfide, oligoarylene sulfide, at a temperature sufficient to dissolve PAS in the reaction mixture described above. And the solution component containing an organic polar solvent is isolate | separated by solid-liquid separation, and solution components are collect | recovered as a filtrate.

  Here, the temperature at which the first solid-liquid separation is performed is not particularly limited as long as the polyarylene sulfide is melt-dissolved. However, in the case of the polyarylene sulfide having the above preferred weight average molecular weight, the temperature exceeds 200 ° C. The temperature is preferably 220 ° C. or higher, more preferably 230 ° C. or higher. Further, when polyarylene sulfide having a particularly high weight average molecular weight, high crystallinity, or high crystallinity is used, a temperature of 250 ° C. or higher can be employed. In such a preferable temperature range, the solubility of polyarylene sulfide in an organic polar solvent is improved, so that it becomes easy to form a uniform solution component, and the viscosity of the solution component tends to decrease as the temperature increases. The separability in the solid-liquid separation operation tends to be improved. On the other hand, the upper limit of the temperature at which solid-liquid separation is performed is preferably 350 ° C. or lower, more preferably 300 ° C. or lower, and further preferably 280 ° C. or lower. Below such upper limit temperature, the polyarylene sulfide or oligoarylene sulfide, which is the target component, does not easily decompose or change, and the organic polar solvent does not easily decompose or change.

  Although there is no restriction | limiting in the pressure at the time of performing 1st solid-liquid separation, 2.0 MPa or less is preferable at a gauge pressure, 1.0 MPa or less is more preferable, and 0.8 MPa or less can be illustrated as a still more preferable range. In general, as the pressure increases, it is necessary to increase the pressure resistance of the device that performs solid-liquid separation, and such a device is required to have a high degree of sealing performance at each part constituting it. Expenses will increase. In the preferred pressure range, generally available solid-liquid separation equipment can be used.

  Here, a method of performing the first solid-liquid separation after removing the low-boiling components contained in the reaction mixture in advance before performing the first solid-liquid separation can also be adopted as a preferable method. Here, the low-boiling components contained in the reaction mixture include, for example, the dihalogenated aromatic compound used in the reaction, water contained in the sulfidizing agent, water generated by the reaction of the sulfidizing agent and the dihalogenated aromatic compound, and the like. These often have higher vapor pressures than products such as organic polar solvents, polyarylene sulfides, oligoarylene sulfides, alkali metal halides, etc. contained in the reaction mixture. Therefore, before performing the first solid-liquid separation, at least a part of these low-boiling components is removed from the reaction mixture, so that the pressure during the first solid-liquid separation is further lower than the preferable pressure range. It is possible to adjust the pressure range so that the pressure during the first solid-liquid separation can be adjusted to 0.5 MPa or less, preferably 0.4 MPa or less, more preferably 0.3 MPa or less. It is.

  As a method for removing the low-boiling components, any method can be used as long as the amount of the low-boiling components contained in the reaction mixture can be reduced. For example, the method can be removed by distillation through a valve connected to the upper part of the reactor. A method of removing by flash transfer can be exemplified, and an inert gas such as nitrogen, helium or argon may be used as the carrier gas. Further, when removing this low boiling point component, only the low boiling point component may be selectively removed using a technique such as rectification, but it is removed as a mixture containing an organic polar solvent together with the low boiling point component. It is also possible.

  The temperature at which the low boiling point component is removed is not particularly limited, but the specific temperature range may be 180 ° C or higher, preferably 200 ° C or higher, while the upper limit is 280 ° C or lower, preferably 260 ° C or lower. Preferably it is 240 degrees C or less, More preferably, 230 degrees C or less can be illustrated. In such a temperature range, not only can low-boiling components be removed in a short time, but also side reactions such as decomposition of arylene sulfide components and organic polar solvents can be favorably suppressed by performing the treatment particularly at the upper limit temperature or lower. As a result, effects such as suppression of coloring of the arylene sulfide component and improvement of separability in the second solid-liquid separation described later (shortening of the solid-liquid separation time and improvement of the purity of the obtained polyarylene sulfide) are obtained. It tends to be. Further, this operation may be performed at a constant temperature or may be performed by changing the temperature stepwise or continuously.

  There is no particular limitation on the amount of low-boiling components removed from the reaction mixture, but when water as a low-boiling component is used as a reference, until the water content is 1% by weight or less based on the organic polar solvent in the reaction mixture. It is preferably removed, more preferably 0.8% by weight or less, and more preferably 0.5% by weight or less. By setting the amount of water contained in the reaction mixture within this preferred range, the pressure during the first solid-liquid separation can be easily adjusted within the preferred range. In addition, by setting the water present in the reaction mixture within the above range, the solubility of inorganic salts such as alkali metal halides present in the reaction mixture is further reduced, so that the alkali metal halogen in the first solid-liquid separation is reduced. As a result, it is possible to further reduce the amount of metal remaining in the polyarylene sulfide and oligoarylene sulfide finally obtained by the present invention.

  If polyarylene sulfide is precipitated in the reaction mixture by removing the low-boiling components, it is heated to a temperature sufficient to dissolve the polyarylene sulfide and then subjected to the first solid-liquid separation. Is also possible.

  The method for performing solid-liquid separation is not particularly limited, and a known method can be employed. Pressure filtration or vacuum filtration that is filtration using a filter, centrifugation or sedimentation that is separation due to a difference in specific gravity between a solid content and a solution. Separation and a combination of these methods can be employed. A decanter separation method in which sedimentation separation is performed before the filtration operation is also a preferable method. The filter used for filtration operation should just be stable on the conditions which perform solid-liquid separation, for example, a wire sieve and a sintered board can be used conveniently. Moreover, the mesh diameter or pore diameter of this filter varies widely depending on the viscosity, pressure, temperature, particle size of the solid component in the slurry, purity of the resulting filtrate (solid content), etc. Can be adjusted. In particular, it is effective to select the mesh diameter or the pore diameter according to the particle diameter in the reaction mixture of the alkali metal halide recovered as a solid content by this filtration operation. The average particle diameter (median diameter) of the alkali metal halide in the reaction mixture can vary widely depending on the composition, temperature, concentration, etc. of the reaction mixture, but as far as the present inventors know, the average particle diameter is 1 There is a tendency to be 100 μm. Accordingly, the preferable average pore diameter of the filter for separating such alkali metal halides by filtration can be exemplified by 0.1 to 80 μm, preferably 0.1 to 50 μm, more preferably 0.25 to 20 μm. 0.5 to 15 μm can be exemplified as a more preferable range. In order to perform solid-liquid separation more efficiently, it is also preferable to perform solid-liquid separation using a filter in which various components insoluble in organic polar solvents, for example, ceramic powder and alkali metal halide powder are previously laminated. It can be illustrated.

  According to the solid-liquid separation operation here, most of the alkali metal halide in the reaction mixture can be separated from the organic polar solvent solution containing polyarylene sulfide and oligoarylene sulfide as a solid content, preferably in the reaction mixture. 90% or more, more preferably 95% or more, and still more preferably 98% or more of the alkali metal halide can be recovered as a solid content. When the solid content separated by solid-liquid separation contains an organic polar solvent solution containing polyarylene sulfide and oligoarylene sulfide, the solid content is washed with a fresh organic polar solvent to obtain polyarylene. It is also possible to reduce the residual amount of sulfide and oligoarylene sulfide in the solid content. This method includes adding a fresh organic polar solvent to the filter on which the solid cake is laminated to separate the solid and liquid, and adding the fresh organic polar solvent to the solid cake and stirring to form a slurry, followed by solid-liquid separation. The conditions for performing these operations are preferably carried out according to the preferred conditions employed for the first solid-liquid separation described above.

(B) Second Solid-Liquid Separation In the present invention, the filtrate component containing polyarylene sulfide, oligoarylene sulfide and organic polar solvent obtained in the first solid-liquid separation is subjected to the following second solid-liquid separation.

  The second solid-liquid separation is characterized in that the filtrate component is subjected to solid-liquid separation after the temperature at which the polyarylene sulfide is not dissolved, and the preferable upper limit temperature is 200 ° C. or lower, more preferably 150 ° C. or lower, more preferably An example is 120 ° C. or lower. In this preferred temperature range, the PAS contained in the filtrate has a strong tendency to exist as a solid content, and in particular, the above-mentioned preferred weight average molecular weight PAS tends to be a solid content. On the other hand, in this preferred temperature range, the oligoarylene sulfide component contained in the filtrate has a strong tendency to be soluble in an organic polar solvent, and the oligoarylene sulfide having the preferred weight average molecular weight described above is particularly soluble in an organic polar solvent under these conditions. The tendency to do is strong. Therefore, under the conditions for performing the second solid-liquid separation, the filtrate obtained by the first solid-liquid separation becomes a slurry containing solid PAS. On the other hand, oligoarylene sulfide is separated as a solution-like filtrate. In addition, 10 degreeC or more can be illustrated as a minimum temperature in the case of 2nd solid-liquid separation, 20 degreeC or more is preferable, 50 degreeC or more is more preferable, and 80 degreeC or more is still more preferable. Above this minimum temperature, the viscosity of the filtrate tends to be low, the solid-liquid separation operation is easy, and the separability between the solid component and the solution component tends to be excellent.

  There is no limitation on the pressure at the time of performing the second solid-liquid separation. For example, the pressure range in the first solid-liquid separation can be exemplified, but the second solid-liquid separation is lower than the first solid-liquid separation. Since the solid-liquid separation operation is performed at the temperature, the operation can be performed under a pressure lower than that of the first solid-liquid separation. Specifically, the pressure range is preferably 2.0 MPa or less as a gauge pressure, more preferably 1.0 MPa or less, still more preferably 0.8 MPa or less, and even more preferably 0.5 MPa or less. In general, as the pressure increases, it is necessary to increase the pressure resistance of the device that performs solid-liquid separation, and such a device is required to have a high degree of sealing performance at each part constituting it. Expenses will increase. In the preferred pressure range, generally available solid-liquid separation equipment can be used.

  The method for performing solid-liquid separation is not particularly limited, and the method exemplified in the first solid-liquid separation can be employed. Pressure filtration or vacuum filtration that is filtration using a filter, difference in specific gravity between solid content and solution Centrifugation, sedimentation separation, and a combination of these methods can be employed. A decanter separation method in which sedimentation separation is performed before the filtration operation is also a preferable method. The filter used for the filtration operation is not particularly limited as long as it is stable under the conditions for solid-liquid separation. For example, commonly used filter media such as a wire mesh filter, a sintered plate, a filter cloth, and filter paper can be suitably used. In addition, the pore size of this filter can be adjusted over a wide range depending on the viscosity, pressure, temperature of the slurry used for the solid-liquid separation operation, the particle size of the solid component in the slurry, and the purity of the resulting filtrate (solid content). Yes. In particular, the particle diameter of PAS recovered as a solid content from the slurry in the second solid-liquid separation operation, that is, the mesh diameter or the pore diameter according to the particle diameter of the solid content present in the slurry subjected to the second solid-liquid separation It is effective to select the filter pore size. Note that the average particle diameter (median diameter) of PAS in the slurry subjected to the second solid-liquid separation can vary widely depending on the composition, temperature, concentration, etc. of the slurry, but as long as the present inventors know, the average The particle size tends to be 1 to 200 μm. Therefore, 0.1-100 micrometers can be illustrated as a preferable average hole diameter of the hole diameter of a filter, 0.25-20 micrometers is preferable, and 0.5-15 micrometers can be illustrated as a more preferable range.

  According to the solid-liquid separation operation here, most of the PAS contained in the filtrate obtained by the first solid-liquid separation can be separated as a solid content, and preferably obtained by the first solid-liquid separation. 80% or more, more preferably 90% or more, and still more preferably 95% or more of the PAS in the filtrate can be recovered as a solid content. In addition, when the solid PAS separated by solid-liquid separation contains an organic polar solvent solution (mother liquor) containing oligoarylene sulfide, the solid content is washed with a fresh solvent to obtain oligoarylene sulfide. It is also possible to reduce the residual amount in the solid content. As this method, there are a method of adding a fresh solvent on a filter in which a solid cake is laminated and solid-liquid separation, a method of adding a fresh solvent to a solid cake and stirring to make a slurry, and then a solid-liquid separation. As examples, the conditions for performing these operations are preferably performed in accordance with the preferable conditions employed for the second solid-liquid separation described above. In addition, the solvent used here should just be what can melt | dissolve an oligoarylene sulfide, Preferably an organic polar solvent can be illustrated.

(12) Other post-processing 1
In the present invention, PAS can be obtained as a solid content by the second solid-liquid separation.

  The solid component thus obtained is a highly pure PAS, which is excellent in that the contents of alkali metal and oligoarylene sulfide are significantly reduced as compared with PAS obtained by a known method. Here, when the solid component contains an organic polar solvent, it is possible to remove the organic polar solvent by adopting a known method as desired. Examples of the method for removing the organic polar solvent include a method of removing by distillation and a method of solvent substitution with various solvents miscible with the organic polar solvent.

  As a specific method of removing by distillation, a method of heating the solid component to preferably 100 to 250 ° C, more preferably 120 to 200 ° C can be exemplified. The organic polar solvent can be efficiently removed by performing this heating under reduced pressure or under an air stream. In addition, the atmosphere at the time of heating can also be performed in a non-oxidizing atmosphere, and this tends to suppress the decomposition, coloring, crosslinking, etc. of PAS. On the other hand, if it is desired to introduce a crosslinked structure into PAS, increase the melt viscosity, and further reduce volatile components, it is possible to select an oxidizing atmosphere. Here, the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere, that is, an inert gas such as nitrogen, helium or argon. It indicates a gas atmosphere, and among these, a nitrogen atmosphere is particularly preferred from the viewpoint of economy and ease of handling. On the other hand, the oxidizing atmosphere refers to an atmosphere having a gas phase oxygen concentration of 5% by volume or more, preferably 10% by volume or more, and air can also be used.

  It is also possible to further wash the PAS from which the organic polar solvent has been removed in this manner using various solvents described later, thereby further reducing the ionic compound, oligoarylene sulfide, and organic polar solvent remaining in the PAS. It tends to be possible.

  Specific examples of the solvent replacement with various solvents include a method of solid-liquid separation after mixing the solid component with various solvents miscible with the organic polar solvent. It is also possible to repeat this operation as desired. It is important that the various solvents used here are miscible with the organic polar solvent, and are selected according to the characteristics of the organic polar solvent, but those that do not substantially cause undesirable side reactions such as decomposition and crosslinking of PAS are preferable. Alcohol, phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1, Halogen solvents such as 1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, cyclopentane, benzene, toluene, xylene, acetone, methyl Ketone solvents such as ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl butyl ketone, acetophenone, etc., carboxyl such as methyl acetate, ethyl acetate, pentyl acetate, octyl acetate, methyl butyrate, ethyl butyrate, pentyl butyrate, methyl salicylate, ethyl formate Examples of the acid ester solvent and water include methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, chloroform, methylene chloride, 1,2-dichloroethane, pentane, hexane, heptane, octane, cyclohexane, Cyclopentane, acetone, methyl acetate, ethyl acetate, water are preferred, methanol, ethanol, propanol, ethylene glycol, chloroform, methylene chloride, 1,2-dichloroether. Emissions, acetone, ethyl acetate, particularly preferably water, methanol, acetone, water is more preferable. These solvents can be used as one kind or a mixture of two or more kinds.

  There are no particular restrictions on the atmosphere in which the solid component and various solvents are brought into contact, but if the PAS component or solvent is subject to oxidative degradation due to conditions such as temperature or time in contact, it is performed in a non-oxidizing atmosphere. It is desirable. There is no particular limitation on the temperature at which the solid component is brought into contact with the solvent, but since it is preferable to carry out under atmospheric pressure, it is desirable that the upper limit temperature be lower than the reflux temperature under atmospheric pressure of the solvent used. In the case of using a preferred solvent, for example, 20 to 150 ° C., preferably 30 to 100 ° C. can be exemplified as a specific temperature range. The time for which the solid component is brought into contact with the solvent varies depending on the type of solvent used, the temperature, and the like, and thus cannot be uniquely limited, but examples include 1 minute to 50 hours.

  The method of bringing the solid component into contact with the solvent is not particularly limited as long as a known general method may be used. For example, the solid component and the solvent are mixed and stirred as necessary, and then the above-described solid-liquid separation operation is performed. Thus, any method such as a method for recovering the solid component, a method for showering the solvent on the solid component on various filters, or a method based on the principle of the Soxhlet extraction method can be used. Although there is no restriction | limiting in particular in the usage-amount of the solvent at the time of making a solid component and a solvent contact, For example, the range of 0.5-100 can be illustrated by the bath ratio with respect to a solid component weight. When the bath ratio is within such a range, it is easy to uniformly mix the solid component and the solvent, and the organic polar solvent can be efficiently separated from the solid component. When the contact between the solid component and the solvent is repeated, a sufficient effect can often be obtained even with a small bath ratio.

  The solid component from which the organic polar solvent thus obtained has been removed contains the solvent used for solvent substitution, and can be dried under normal pressure and / or reduced pressure as desired. The drying temperature is preferably in the range of 50 to 280 ° C, and more preferably in the range of 70 to 250 ° C. The drying atmosphere may be any of an inert atmosphere such as nitrogen, helium and reduced pressure, an oxidizing atmosphere such as oxygen and air, and a mixed atmosphere of air and nitrogen, preferably under reduced pressure, particularly under normal pressure. It is preferable to dry again under reduced pressure after drying to remove most of the solvent. The drying time is preferably 0.5 to 50 hours, preferably 1 to 30 hours, and more preferably 1 to 20 hours.

  The PAS obtained in the present invention is of a sufficiently high quality, but it can also be treated at a temperature of 130 to 260 ° C. in order to remove volatile components or to increase the cross-linking molecular weight. is there. When carrying out dry heat treatment for the purpose of suppressing cross-linking high molecular weight and removing volatile matter, the temperature is preferably from 130 to 250 ° C, more preferably from 160 to 250 ° C. Further, it is desirable that the oxygen concentration is less than 2% by volume, more preferably less than 1% by volume. Drying under reduced pressure is also a preferred method. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and still more preferably 1 to 10 hours. When the dry heat treatment is performed for the purpose of increasing the cross-linking molecular weight, the temperature is preferably 160 to 260 ° C, more preferably 170 to 250 ° C. Further, it is desirable that the oxygen concentration is 2% by volume or more, more preferably 8% by volume or more. The treatment time is preferably 1 to 100 hours, more preferably 2 to 50 hours, and even more preferably 3 to 25 hours. The heat treatment apparatus may be a normal hot air dryer or a heating apparatus with a rotary blade or a stirring blade. However, for efficient and more uniform treatment, a heating device with a rotary blade or a stirring blade is used. Is more preferable.

(13) Other post-processing 2
By the second solid-liquid separation, an oligoarylene sulfide can be obtained as a filtrate component (which may contain a solid component depending on the temperature).

  If desired, the oligoarylene sulfide can be recovered as a solid by removing the organic polar solvent from the filtrate components. Examples of the method for removing the organic polar solvent include a method of removing by distillation and a method of contacting with a second solvent miscible with the organic polar solvent.

  As a specific method of removing by distillation, a method of heating the filtrate component to preferably 20 to 250 ° C, more preferably 40 to 200 ° C, still more preferably 100 to 200 ° C, and still more preferably 120 to 200 ° C. It can be illustrated. It is possible to efficiently remove the organic polar solvent by performing this heating under reduced pressure or under an air stream, and further under stirring. In addition, it is preferable to perform the atmosphere at the time of heating in non-oxidizing atmosphere, and it exists in the tendency which can suppress decomposition | disassembly, coloring, bridge | crosslinking, etc. of oligoarylene sulfide by this. Here, the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere, that is, an inert gas such as nitrogen, helium or argon. It indicates a gas atmosphere, and among these, a nitrogen atmosphere is particularly preferred from the viewpoint of economy and ease of handling.

  It is also possible to further wash the oligoarylene sulfide from which the organic polar solvent has been removed in this way, using a second solvent described later, whereby the ionic compound or organic polar solvent remaining in the oligoarylene sulfide can be removed. It tends to be further reduced.

  As a specific method for obtaining oligoarylene sulfide by solvent replacement of the filtrate component with a second solvent, contact with a second solvent in which oligoarylene sulfide does not dissolve or oligoarylene sulfide is difficult to dissolve, A method for recovering oligoarylene sulfide as a solid component can be exemplified.

  The reaction system pressure when the filtrate component is brought into contact with the second solvent is preferably normal pressure or slight pressure, and particularly preferably normal pressure. Such a pressure system has the advantage that the members for constructing it are inexpensive, and from this point of view, the pressure of the system in which the filtrate component and the second solvent are brought into contact is a pressure condition that requires an expensive pressure vessel. Should be avoided. A preferable solvent as the second solvent is preferably one that does not substantially cause an undesirable side reaction such as decomposition or crosslinking of oligoarylene sulfide. For example, methanol, ethanol, propanol, isopropanol, butanol, pentanol, ethylene glycol, propylene Alcohol / phenol solvents such as glycol, phenol, cresol, polyethylene glycol, hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, cyclopentane, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl butyl ketone, Ketone solvents such as acetophenone, methyl acetate, ethyl acetate, pentyl acetate, octyl acetate, methyl butyrate, ethyl butyrate, pentyl butyrate, methyl salicylate Carboxylic acid ester solvents such as ethyl formate and water, and methanol, ethanol, propanol, isopropanol, butanol, pentanol, ethylene glycol, propylene glycol, pentane, hexane, heptane, octane, cyclohexane, cyclopentane , Acetone, methyl acetate, and ethyl acetate are preferred, and methanol, ethanol, isopropanol, ethylene glycol, pentane, hexane, heptane, octane, cyclohexane, acetone, ethyl acetate, and water are particularly preferred. These solvents can be used as one kind or a mixture of two or more kinds.

  There is no particular limitation on the temperature at which the filtrate component is brought into contact with the second solvent, but the upper limit temperature is desirably set to the reflux condition temperature under normal pressure of the second solvent to be used. When using, 20-100 degreeC can be illustrated as a preferable temperature range, for example, More preferably, 25-80 degreeC can be illustrated. The time for which the filtrate component is brought into contact with the second solvent varies depending on the type of solvent used, the temperature, and the like, and thus cannot be uniquely limited.

  As a method of bringing the filtrate component into contact with the second solvent, a method of adding the second solvent to the filtrate component and stirring and mixing as necessary, while stirring the filtrate component in the second solvent as necessary In addition, the method of mixing can be illustrated. According to this method, since the oligoarylene sulfide is precipitated as a solid content with the contact between the filtrate component and the second solvent, it is possible to recover the solid oligoarylene sulfide using a known solid-liquid separation method. It is. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. If the organic polar solvent, alkali metal halide, sulfiding agent, and dihaloaromatic compound remain in the oligoarylene sulfide obtained after the solid-liquid separation, the obtained oligoarylene sulfide and the second solvent are used again. These can be further reduced by contact.

  Since the oligoarylene sulfide thus obtained contains the second solvent used for contact with the filtrate component, it can be dried under normal pressure and / or reduced pressure as desired. The drying temperature is preferably in the range of 50 to 200 ° C, more preferably in the range of 70 to 150 ° C. The drying atmosphere may be an inert atmosphere such as nitrogen, helium or reduced pressure, an oxidizing atmosphere such as oxygen or air, or a mixed atmosphere of air and nitrogen, but it is preferably performed under reduced pressure, and is dried under normal pressure. It is also a preferable method to remove most of the solvent and then dry again under reduced pressure. The drying time is preferably 0.5 to 50 hours, preferably 1 to 30 hours, and more preferably 1 to 20 hours.

(14) Generated PAS
The PAS obtained by the present invention is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is used not only for injection molding, injection compression molding and blow molding, but also by extrusion molding to form sheets and films. , And can be formed into extruded products such as fibers and pipes. Further, as a remarkable effect manifested by the present invention, the metal content contained in PAS is remarkably reduced as compared with PAS obtained by a known method. Therefore, it is particularly preferable for applications in which electrical characteristics, particularly insulation characteristics, are important. It is possible to use. At the same time, the oligomer component content is remarkably small as compared with PAS obtained by a known method, so that it can be preferably used for applications in which chemical resistance, oligomer elution amount and gas generation amount are regarded as important.

  In addition, the PAS obtained in the present invention may be used alone, or, as desired, inorganic fillers such as glass fiber, carbon fiber, titanium oxide, calcium carbonate, antioxidant, heat stabilizer, ultraviolet absorption. Agents, coloring agents, etc. can also be added. Polyamide, polysulfone, polyphenylene ether, polycarbonate, polyethersulfone, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, epoxy group, carboxyl group, carboxylic acid ester Contains resins such as olefin copolymers, polyolefin elastomers, polyether ester elastomers, polyether amide elastomers, polyamide imides, polyacetals, and polyimides having functional groups such as groups and acid anhydride groups. Rukoto can also.

  Applications include sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners. , Speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts, etc .; VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser discs (registered trademark) / compact discs, lighting parts, refrigerator parts, air conditioner parts , Homes such as typewriter parts, word processor parts, office electrical product parts; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, motor parts, lighters, typewriters Machine-related parts such as: Optical instruments such as microscopes, binoculars, cameras, watches, etc., precision machine-related parts; water faucet tops, mixing faucets, pump parts, pipe joints, water volume control valves, relief valves, Water temperature sensor, water volume sensor, water meter housing and other water-related parts; valve alternator terminal, alternator connector, IC regulator, various valves such as exhaust gas valve, fuel-related / exhaust / intake system pipes, air intake nozzle snorkel, intake Manifold, Pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, Heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, distributor, starter switch, starter relay, transmission wire harness, window washer nozzle, air conditioner panel switch board, fuel Related coils for electromagnetic valves, connectors for fuses, horn terminals, electrical component insulation plates, Examples include step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, fuel tanks, ignition device cases, vehicle speed sensors, cable liners, and other automobile / vehicle related parts.

  As a method for producing a PAS film using the PAS obtained according to the present invention, a known melt film-forming method can be employed. For example, after melting PAS in a single or twin screw extruder, More by a method of making a film by cooling on an extrusion cooling drum, or by a biaxial stretching method in which the film thus produced is stretched longitudinally and laterally by a roller-type longitudinal stretching apparatus and a transverse stretching apparatus called a tenter. Although it can manufacture, it is not specifically limited to this.

  The PAS film thus obtained has excellent mechanical properties, electrical properties, heat resistance, dielectric film applications for film capacitors and chip capacitors, circuit boards, insulation substrate applications, motor insulation film applications, It can be suitably used for various applications such as transformer insulating film applications and release film applications.

  As a method for producing a PAS fiber using the PAS obtained by the present invention, a known melt spinning method can be applied. For example, kneading while supplying a raw material PAS chip to a single-screw or twin-screw extruder Then, a method of extruding from a spinneret through a polymer stream line changer installed at the tip of the extruder, a filtration layer, etc., cooling, stretching, heat setting, etc. can be adopted, but it is particularly limited to this. It is not something.

  The monofilaments or short fibers of PAS thus obtained can be suitably used for various applications such as paper-making dryer canvas, net conveyors, bag filters, and insulating paper.

  The present invention will be described more specifically with reference to the following examples. These examples are illustrative and not limiting.

<Molecular weight measurement>
The molecular weight of polyarylene sulfide was calculated in terms of polystyrene by gel permeation chromatography (GPC), which is a type of size exclusion chromatography (SEC). The measurement conditions for GPC are shown below.
Equipment: Senshu Science SSC-7100
Column name: Senshu Science GPC3506
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature: 250 ° C
Pump bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection amount: 300 μL (slurry: about 0.2% by weight).

<Quantification of alkali metal content>
Quantification of the alkali metal content contained in PAS and oligoarylene sulfide was carried out as follows.
(A) The sample was weighed in a quartz crucible and incinerated using an electric furnace.
(B) After the ashed product was dissolved with concentrated nitric acid, the volume was made constant with diluted nitric acid.
(C) The obtained constant volume solution was subjected to ICP gravimetric analysis (apparatus; 4500 manufactured by Agilent) and ICP emission spectroscopic analysis (apparatus; Optima 4300DV manufactured by PerkinElmer).

<Low molecular compound content of polyarylene sulfide>
The content of the low molecular weight compound of polyarylene sulfide was estimated as the weight fraction of the soluble portion of hot chloroform by extracting PAS with hot chloroform. Extraction operation was performed by the following method.
(A) Soxhlet extraction was performed on 5 g of PAS using 100 g of chloroform at a bath temperature of 85 ° C. for 5 hours.
(B) Chloroform was distilled off from the extract obtained using a rotary evaporator.
(C) Next, vacuum drying was performed at 70 ° C. for 3 hours, the weight of the obtained solid content was determined, and the weight fraction with respect to the weight of PAS was calculated.

[Reference Example 1]
<Reaction 1 between sulfidizing agent and dihalogenated aromatic compound>
In a stainless steel autoclave equipped with a stirrer, 58.4 g (0.50 mol) of a 48 wt% aqueous solution of sodium hydrosulfide and 23.0 g (0.53 mol) of 96% sodium hydroxide were dissolved in 50 g of ion-exchanged water. An aqueous solution, 198 g (2.00 mol) of N-methyl-2-pyrrolidone (NMP) was charged. After the rectification tower was attached to the autoclave, it was gradually heated to an internal temperature of 210 ° C. over about 3 hours while stirring through nitrogen at normal pressure. During this period, 80 g was distilled out of the system from the rectification column. The amount of hydrogen sulfide scattered was 0.012 mol. As a result of analyzing the distillate by gas chromatography, it was found that the distillate was a mixture of 76.5 g of water and 3.5 g of NMP, and the amounts of water and NMP in the reaction system were 3.8 g and 195 g, respectively. .

  After completion of the distillation, the reaction vessel was cooled to about 160 ° C., 73.1 g (0.50 mol) of p-dichlorobenzene (p-DCB) and 300 g (3.0 mol) of NMP were added, and the reaction vessel was charged with nitrogen. Sealed under gas. While stirring, the mixture was heated and heated from 200 ° C. to 250 ° C. over about 50 minutes, held at 250 ° C. for 2 hours, and then rapidly cooled to near room temperature.

[Reference Example 2]
Here, an example is shown in which the PPS component (mixture of PPS and oligophenylene sulfide) is recovered from the reaction mixture obtained in Reference Example 1 by a general technique.

  100 g of the reaction product obtained in Reference Example 1 was collected, and 300 g of a 1% aqueous acetic acid solution was added. After stirring to form a slurry, the mixture was heated to 70 ° C. and stirring was continued for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid content was subjected to vacuum drying at 70 ° C. overnight to obtain about 8.2 g of a dry solid (yield 97% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was a polymer composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis (apparatus; FTIR-8100A manufactured by Shimadzu Corporation), and has a weight average molecular weight of 16500 from GPC measurement. It was found to be a polymer. The low molecular compound content was 4.8%, and the alkali metal content was 8000 ppm. The PPS obtained by a general recovery method that does not perform the first solid-liquid separation and the second solid-liquid separation, which is a feature of the present invention, contains an extremely large number of low-molecular compounds and metal components.

[Reference Example 3]
<Reaction 2 between sulfidizing agent and dihalogenated aromatic compound>
Here, in the reaction of the reaction between the sulfidizing agent and the dihalogenated aromatic compound, a reaction example in which more organic polar solvent for the sulfur component of the sulfidizing agent is used than in Reference Example 1 is shown.

  In a stainless steel autoclave equipped with a stirrer, 11.7 g (0.100 mol) of a 48 wt% aqueous solution of sodium hydrosulfide and 4.60 g (0.105 mol) of 96% sodium hydroxide were added to 4.98 g of ion-exchanged water. Dissolved aqueous solution, 15.0 g (0.102 mol) of p-DCB and 500 g (5.04 mol) of NMP were charged. After sufficiently replacing the reaction vessel with nitrogen, the inside of the reaction system was pressurized to 0.3 MPa (gauge pressure) with nitrogen. While stirring, the temperature was raised from room temperature to 200 ° C. over about 1.5 hours. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 30 minutes, held at 250 ° C. for 2 hours, and then rapidly cooled to near room temperature.

[Reference Example 4]
Here, an example in which the PPS component (a mixture of PPS and oligophenylene sulfide) is recovered from the reaction mixture obtained in Reference Example 3 is shown.

  100 g of the reaction product obtained in Reference Example 3 was collected, and 300 g of a 3% aqueous acetic acid solution was added. After stirring to form a slurry, the mixture was heated to 70 ° C. and stirring was continued for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid content was subjected to vacuum drying at 70 ° C. overnight to obtain about 1.8 g of dry solid (yield 89% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis that the polymer was composed of phenylene sulfide units.

[Reference Example 5]
Here, it describes about the result of having confirmed the melt | dissolution behavior with respect to NMP of the PPS component and sodium chloride obtained in Reference Examples 2 and 4.

  0.25 g of the PPS component obtained in Reference Example 2 and 25 g of NMP were charged into a pressure vessel made of glass. When the container was sealed and heated to 200 ° C. with stirring, most of the PPS component remained undissolved. When the temperature was raised to 250 ° C. and stirring, a uniform solution was obtained, and it was confirmed that the PPS component was completely dissolved.

  The dissolution behavior of the PPS component obtained in Reference Example 4 was also confirmed in the same manner. As a result, a part of the PPS component remained undissolved at 200 ° C., but it was confirmed that it completely dissolved at 235 ° C.

  Furthermore, when the dissolution behavior of sodium chloride was also confirmed, it was confirmed that it hardly dissolved even at 250 ° C. and remained in a solid form.

[Example 1]
Here, a method for recovering the PPS component by subjecting the reaction mixture obtained in Reference Example 1 to first solid-liquid separation and second solid-liquid separation will be exemplified.

<First solid-liquid separation>
100 g of the reaction solution obtained in Reference Example 1 was charged into a stainless steel pressure vessel having a bottom plug valve and a glass filter (average opening 10 μm) at the bottom. After heating to 180 ° C. with stirring under normal pressure, the vessel was sealed under nitrogen. Subsequently, it heated to 250 degreeC and hold | maintained for 1 hour.

  A cooling pipe was attached to the bottom plug valve outlet of the container, and the bottom plug valve was opened for filtration. The filtrate was collected while introducing nitrogen at 0.3 MPa into the container at the stage when the filtration rate was lowered. By this operation, about 84 g of filtrate and 14 g of solid content were recovered.

<Second solid-liquid separation>
The filtrate obtained by the first solid-liquid separation was heated to 100 ° C. At this stage, the filtrate obtained by the first solid-liquid separation was in the form of a slurry containing an insoluble part. The slurry was suction filtered with a PTEF filter (average opening 10 μm). By this operation, about 11 g of solid content and about 71 g of filtrate were recovered.

The obtained solid content was dispersed in 300 g of a 1% aqueous acetic acid solution, then heated to 70 ° C. and stirred for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid content was subjected to vacuum drying at 70 ° C. overnight to obtain about 7.1 g of a dry solid (yield 84% based on the charged sulfidizing agent).
As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis that it was a polymer (PPS) composed of phenylene sulfide units, and was a polymer having a weight average molecular weight of 18000 from GPC measurement. . Further, the low molecular compound content was 0.3%, the alkali metal content was 550 ppm, and it was found that the PPS was extremely high in purity.

[Example 2]
Here, a method for recovering the PPS component by subjecting the reaction mixture obtained in Reference Example 3 to the first solid-liquid separation and the second solid-liquid separation will be exemplified.

<First solid-liquid separation>
100 g of the reaction solution obtained in Reference Example 2 was charged into a stainless steel pressure-resistant container equipped with a bottom plug valve and a glass filter (average opening 10 μm) at the bottom. After heating to 180 ° C. with stirring under normal pressure, the vessel was sealed under nitrogen. Subsequently, it heated to 235 degreeC and hold | maintained for 1 hour.

  A cooling pipe was attached to the bottom plug valve outlet of the container, and the bottom plug valve was opened for filtration. The filtrate was collected while introducing nitrogen at 0.3 MPa into the container at the stage when the filtration rate was lowered. By this operation, about 94 g of filtrate and about 3 g of solid content were recovered.

<Second solid-liquid separation>
The filtrate obtained by the first solid-liquid separation was heated to 100 ° C. At this stage, the filtrate obtained by the first solid-liquid separation was in the form of a slurry containing an insoluble part. This slurry was subjected to suction filtration with a PTFE filter (average opening 10 μm). By this operation, about 2 g of solid content and about 90 g of filtrate were recovered.

  The obtained solid content was dispersed in 300 g of a 3% aqueous acetic acid solution, then heated to 70 ° C. and stirred for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight to obtain about 1.1 g of dried solid (yield 55% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis that it was a polymer (PPS) composed of phenylene sulfide units, and was a polymer having a weight average molecular weight of 7000 from GPC measurement. . Further, the low molecular compound content was 0.3%, the alkali metal content was 350 ppm, and it was found that the PPS was extremely high in purity.

[Comparative Example 1]
Here, the case where the first solid-liquid separation was not performed in the recovery of the reaction mixture obtained in Reference Example 1 is illustrated.

  100 g of the reaction solution obtained in Reference Example 1 was heated to 100 ° C. and stirred. This reaction solution was subjected to suction filtration while hot through a PTFE filter (average opening 10 μm). By this operation, about 29 g of solid content and about 69 g of filtrate were recovered.

  The obtained solid was treated with an acetic acid aqueous solution and then ion-exchanged water in the same manner as in Example 1 and dried to obtain about 7.8 g of a dry solid (yield 92% based on the charged sulfidizing agent).

  As a result of analyzing the PPS thus obtained, it was found to be a polymer having a weight average molecular weight of 17,500. The low molecular compound content was 1.4%, and the alkali metal content was 7700 ppm.

  As is clear from the comparison between Comparative Example 1 and Example 1, it can be seen that the first solid-liquid separation is indispensable in order to obtain high-purity PPS.

[Comparative Example 2]
Here, the case where the second solid-liquid separation was not performed in the recovery of the reaction mixture obtained in Reference Example 1 is illustrated.

  Using the reaction solution obtained in Reference Example 1 in the same manner up to the first solid-liquid separation, the filtrate components obtained in the first solid-liquid separation were treated with acetic acid aqueous solution and then ion exchange in the same manner as in Example 1. By treating with water and drying, about 7.8 g of a dry solid (yield 92% with respect to the charged sulfidizing agent) was obtained.

  As a result of analyzing the PPS thus obtained, it was found to be a polymer having a weight average molecular weight of 16,500. The low molecular compound content was 4.7%, and the alkali metal content was 700 ppm.

  From Comparative Example 2 and Example 1, it can be seen that the second solid-liquid separation is indispensable in order to obtain high-purity PPS.

[Example 3]
Here, a method for recovering oligophenylene sulfide from the filtrate components obtained by the second solid-liquid separation is illustrated.

  The second solid-liquid separation was carried out in the same manner as in Example 2, and the obtained filtrate components were dispersed in 300 g of 5% aqueous acetic acid, and then heated to 70 ° C. and stirred for 30 minutes. The slurry was filtered using a filter paper having an average pore diameter of 1 μm to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight to obtain about 0.56 g of dried solid (yield 28% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was a polymer (PPS) composed of phenylene sulfide units from an absorption spectrum in infrared spectroscopic analysis, an oligomer having a weight average molecular weight of 1000 from GPC measurement, and containing an alkali metal. The amount was 40 ppm, which proved to be a highly pure oligomer with a very low metal content. Further, from the molecular weight information by MALDI-TOF-MS, it was found that this oligomer is mainly composed of cyclic polyphenylene sulfide.

[Example 4]
Here, a method of recovering the PPS component by removing the low boiling point component from the reaction mixture obtained in Reference Example 1 and then subjecting it to the first solid-liquid separation and the second solid-liquid separation will be exemplified.

<First solid-liquid separation>
100 g of the reaction solution obtained in Reference Example 1 was charged into a stainless steel pressure vessel having a bottom plug valve and a glass filter (average opening 10 μm) at the bottom. After heating to 180 ° C. with stirring under normal pressure, the vessel was sealed under nitrogen. Subsequently, after heating up to 230 degreeC, the valve | bulb of the upper part of a reactor was open | released and the low boiling point component was removed. The component distilled off at this time was collected by a receiver through a cooling pipe. The total amount of components distilled out by this operation was about 2.5 g. As a result of analysis, it was found that water contained about 1.8 g, p-DCB 0.3 g and NMP 0.4 g.

  Next, after heating to 250 ° C., a cooling pipe was attached to the outlet of the bottom plug valve of the container, and the bottom plug valve was opened to perform filtration. The filtrate was collected while introducing nitrogen at 0.3 MPa into the container at the stage when the filtration rate was lowered. By this operation, about 82 g of filtrate and 14 g of solid content were recovered.

<Second solid-liquid separation>
The filtrate obtained by the first solid-liquid separation was heated to 100 ° C. At this stage, the filtrate obtained by the first solid-liquid separation was in the form of a slurry containing an insoluble part. The slurry was suction filtered with a PTEF filter (average opening 10 μm). By this operation, about 11 g of solid content and about 70 g of filtrate were recovered.

  The obtained solid content was dispersed in 300 g of a 1% aqueous acetic acid solution, then heated to 70 ° C. and stirred for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight to obtain about 7.2 g of a dry solid (yield of 85% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis that it was a polymer (PPS) composed of phenylene sulfide units, and was a polymer having a weight average molecular weight of 18000 from GPC measurement. . The low molecular compound content is 0.3% and the alkali metal content is 370 ppm. After removing the low-boiling components from the reaction mixture, the PPS is subjected to the first solid-liquid separation and the second solid-liquid separation. It was found that PPS with higher purity can be obtained by recovering the components.

[Example 5]
Here, a method of recovering the PPS component by removing the low boiling point component from the reaction mixture obtained in Reference Example 3 and then subjecting it to the first solid-liquid separation and the second solid-liquid separation will be exemplified.

<First solid-liquid separation>
100 g of the reaction solution obtained in Reference Example 3 was charged in a stainless steel pressure vessel equipped with a bottom plug valve and a glass filter (average opening 10 μm) at the bottom. After heating to 180 ° C. with stirring under normal pressure, the vessel was sealed under nitrogen. Subsequently, after heating to 210 ° C., the valve at the top of the reactor was opened to remove low boiling point components. The component distilled off at this time was collected by a receiver through a cooling pipe. The total amount of components distilled by this operation was about 2.5 g. As a result of analysis, it was found that water contained about 2.2 g, p-DCB about 0.05 g and NMP about 0.25 g. .

  Next, after heating to 235 ° C., a cooling pipe was attached to the outlet of the bottom plug valve of the container, and the bottom plug valve was opened to perform filtration. The filtrate was collected while introducing nitrogen at 0.3 MPa into the container at the stage when the filtration rate was lowered. By this operation, about 92 g of filtrate and about 3 g of solid content were recovered.

<Second solid-liquid separation>
The filtrate obtained by the first solid-liquid separation was heated to 100 ° C. At this stage, the filtrate obtained by the first solid-liquid separation was in the form of a slurry containing an insoluble part. This slurry was subjected to suction filtration with a PTFE filter (average opening 10 μm). By this operation, about 2 g of solid content and about 89 g of filtrate were recovered.

  The obtained solid content was dispersed in 300 g of a 3% aqueous acetic acid solution, then heated to 70 ° C. and stirred for 30 minutes. The slurry was filtered through a glass filter (average pore diameter of 10 to 16 μm) to obtain a solid content. The operation of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain the solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight to obtain about 1.2 g of dry solid (yield 59% based on the charged sulfidizing agent).

  As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis that it was a polymer (PPS) composed of phenylene sulfide units, and was a polymer having a weight average molecular weight of 7000 from GPC measurement. . The low molecular compound content is 0.3% and the alkali metal content is 260 ppm. After removing the low-boiling components from the reaction mixture, the PPS is subjected to the first solid-liquid separation and the second solid-liquid separation. It was found that PPS with higher purity can be obtained by recovering the components.

Claims (9)

A polyarylene sulfide having a weight average molecular weight of 5,000 to 1,000,000 and a weight average molecular weight of 200 to 200 , which is obtained by bringing a sulfidizing agent and a dihalogenated aromatic compound into contact with each other in an organic polar solvent. 2,500 oligo arylene sulfide to a method of recovering the polyarylene sulfide from the reaction mixture containing the alkali metal halide and an organic polar solvent, at a temperature sufficient to dissolve the polyarylene sulfide (a) in the reaction mixture the polyarylene sulfide by punished the reaction mixture at some 230 ° C. or higher in the first solid-liquid separation to obtain a filtrate component containing the oligo arylene sulfide and organic polar solvent, (b) then, the poly said filtrate component The filtrate is adjusted to a temperature at which the arylene sulfide does not dissolve. Method for producing a polyarylene sulfide, wherein the punished minute to second solid-liquid separation. The method for producing polyarylene sulfide according to claim 1, wherein the temperature at which the first solid-liquid separation is performed is 235 ° C or higher . 3. The method for producing polyarylene sulfide according to claim 1, wherein the temperature at which the second solid-liquid separation is performed is 200 ° C. or less. The method for producing polyarylene sulfide according to any one of claims 1 to 3, wherein the temperature at which the second solid-liquid separation is performed is 150 ° C or lower. The method for producing polyarylene sulfide according to any one of claims 1 to 4, wherein the solid content is precipitated by centrifugation before the first solid-liquid separation and / or the second solid-liquid separation. 6. The method for producing polyarylene sulfide according to claim 1, wherein 90% or more of the alkali metal halide in the reaction mixture is separated as a solid content by the first solid-liquid separation. The method for producing polyarylene sulfide according to any one of claims 1 to 6, wherein the pressure during the first and second solid-liquid separation is 1.0 MPa or less. The method for producing a polyarylene sulfide according to any one of claims 1 to 7, wherein the organic polar solvent is an organic amide solvent. The method for producing a polyarylene sulfide according to any one of claims 1 to 8, wherein the dihalogenated aromatic compound is dichlorobenzene.