JP2009227972A - Method for separating polyarylene sulfide and oligoarylene sulfide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyarylene sulfide with diminished impurity components and an oligoarylene sulfide consisting primarily of a cyclic oligoarylene sulfide. <P>SOLUTION: At least (a) a polyarylene sulfide, (b) a sulfidizing agent and (c) a dihalogenated aromatic compound are brought into a reaction in an organic polar solvent to prepare a reaction mixture comprising at least a polyarylene sulfide, an oligoarylene sulfide, an alkali metal halide and an organic polar solvent, and the reaction mixture is subjected to solid-liquid separation (B) in a temperature region in which the polyarylene sulfide does not dissolve and the oligoarylene sulfide is soluble, or the reaction mixture is subjected to solid-liquid separation (A) at a temperature sufficient to dissolve the polyarylene sulfide to obtain a filtrate component comprising the polyarylene sulfide, oligoarylene sulfide and organic polar solvent and the filtrate component is subjected to the solid-liquid separation (B). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a process for producing polyarylene sulfide and oligoarylene sulfide. More specifically, the present invention relates to a method for separating polyarylene sulfide and oligoarylene sulfide, which produces a polyarylene sulfide with reduced impurity components, and a method for producing an oligoarylene sulfide mainly composed of cyclic oligoarylene sulfide. .

  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.

  As a typical method for reducing the above-mentioned problem in PAS, that is, the amount of metal contained in PAS, for example, a method of repeatedly performing hot water washing for a long time at 120 ° C. or lower with PPS containing 1000 ppm or more of alkali metal obtained by the above method (For example, refer to Patent Document 2), a reaction product containing PPS obtained by reacting sodium hydrosulfide, sodium hydroxide and p-dichlorobenzene in N-methyl-pyrrolidone was repeatedly washed with water and warm water, Further, a method of repeatedly washing with ion-exchanged water after washing with an acidic aqueous solution (see, for example, Patent Document 3), a method of repeatedly washing PPS in the presence of a surfactant (see, for example, Patent Document 4), and the like are disclosed. Yes. 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.

  In addition, as a method for separating polyarylene sulfide and oligoarylene sulfide to obtain polyarylene sulfide having reduced oligoarylene sulfide, a method of washing PAS with an organic solvent (see, for example, Patent Document 5) or under reduced pressure. A method for removing a polymerization solvent or a low molecular weight substance (for example, see Patent Documents 6 and 7) has been proposed. 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.

  In the above method, it is difficult to achieve both reduction of metal content and oligomer component, and nothing is mentioned about using polyarylene sulfide, which is a feature of the present invention, as a raw material.

  As a method for obtaining an arylene sulfide-based polymer using polyarylene sulfide as a raw material, a prepolymer having an alkali thiolate group at at least one terminal obtained by depolymerization by causing an alkali metal sulfide to act on the polyarylene sulfide A method for polymerizing a dihalogenated aromatic compound is disclosed (for example, see Patent Document 8). In this method, first, a polyarylene sulfide and an alkali metal sulfide are allowed to act to obtain a prepolymer having an alkali thiolate group at at least one terminal, and then the prepolymer and a dihalogenated aromatic compound are polymerized. It is essential that the reaction of the polyarylene sulfide, the sulfidizing agent and the dihalogenated aromatic compound are reacted at the same time as in the present invention. There were many problems to be solved such as being complicated. Furthermore, since polyarylene sulfide and oligoarylene sulfide, which are the characteristics of the present invention, were not separated, the resulting polyarylene sulfide contained an oligomer component as an impurity.

  On the other hand, arylene sulfides having a cyclic structure (cyclic oligoarylene sulfides) can be applied to highly functional materials and functional materials based on the properties resulting from their cyclic properties, for example, properties as compounds with inclusion ability In recent years, it has attracted attention for its specificity derived from its structure, such as its use as an effective monomer for the synthesis of high molecular weight linear polymers by ring-opening polymerization.

  A method of reacting an alkali metal sulfide with a polyhaloaromatic compound in an organic amide solvent as described above, or a prepolymer and dihalogenation obtained by depolymerizing an alkali metal sulfide with polyarylene sulfide. In the production of polyarylene sulfide represented by a method of polymerizing aromatic compounds, the oligoarylene sulfide produced as an impurity contains at least this cyclic oligoarylene sulfide.

  As a method for recovering such cyclic oligoarylene sulfide, p-dichlorobenzene as a dihalogenated aromatic compound and sodium sulfide as an alkali metal sulfide are reacted in N-methylpyrrolidone which is an organic polar solvent, and then heated. A method is disclosed in which a mixture of polyphenylene sulfide and oligophenylene sulfide obtained by removing water under reduced pressure and then washing with water is recovered from the saturated solution portion of the extract obtained by extraction with methylene chloride. (For example, refer to Patent Document 9). In this method, after the mixture of polyphenylene sulfide and oligophenylene sulfide is obtained, the separation of polyphenylene sulfide and oligomer components is complicated, and the operation is complicated, and a large amount of halogen solvent is required. It was a poor method and improvement was desired.

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 04-7334 A (Claims) JP 05-163349 A (page 7)

  An object of the present invention is to solve the above-described conventional techniques, to produce a polyarylene sulfide having a reduced impurity component, and to provide a method for producing an oligoarylene sulfide mainly composed of a cyclic oligoarylene sulfide.

In response to the above problems, the present invention
1. At least (a) polyarylene sulfide,
A reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent, obtained by reacting (b) a sulfidizing agent and (c) a dihalogenated aromatic compound in an organic polar solvent, A method for separating polyarylene sulfide and oligoarylene sulfide, wherein the solid-liquid separation (B) is performed in a temperature range in which polyarylene sulfide is not dissolved and oligoarylene sulfide is soluble.
2. At least (a) polyarylene sulfide,
A reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent, obtained by reacting (b) a sulfidizing agent and (c) a dihalogenated aromatic compound in an organic polar solvent, By performing solid-liquid separation (A) at a temperature sufficient to dissolve the polyarylene sulfide, a filtrate component containing polyarylene sulfide, oligoarylene sulfide and an organic polar solvent is obtained, and then the filtrate component is dissolved in the polyarylene sulfide. A method for separating polyarylene sulfides and oligoarylene sulfides, which is subjected to solid-liquid separation (B) after the temperature is not increased.
3. 3. The method for separating polyarylene sulfide and oligoarylene sulfide according to item 2, wherein the temperature at which the solid-liquid separation (A) is performed is a temperature exceeding 200 ° C.
4). The polyarylene sulfide and the oligo according to any one of items 1 to 3, wherein the oligoarylene sulfide is obtained as a solid content from the filtrate component containing the oligoarylene sulfide obtained by the solid-liquid separation (B). Separation method of arylene sulfide.
5. At least (a) polyarylene sulfide, (b) a sulfidizing agent, and (c) an organic polar solvent used in the reaction in an organic polar solvent are used in an amount of 50 with respect to 1 mole of a sulfur component in the reaction mixture. The method for separating polyarylene sulfides and oligoarylene sulfides according to any one of items 1 to 4, wherein the method is performed in a liter or less.
6). At least (a) the polyarylene sulfide, (b) the sulfidizing agent, and (c) the organic polar solvent when the dihalogenated aromatic compound is reacted in the organic polar solvent, 1 is used per 1 mol of the sulfur component in the reaction mixture. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of items 1 to 5, wherein 25 liters or more is used.
7). Item 4 to Item 6, wherein the oligoarylene sulfide obtained as a solid content contains 50% or more of cyclic oligoarylene sulfide having 4 to 50 repeating units represented by the following formula (1): The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of the above.

8). Any one of Items 1 to 7, wherein a polyarylene sulfide obtained by contacting a sulfidizing agent and a dihalogenated aromatic compound in an organic polar solvent is used as the polyarylene sulfide (a). A method for separating polyarylene sulfide and oligoarylene sulfide according to claim 1.
9. Polyarylene sulfide and oligoarylene obtained by heating and reacting a sulfidizing agent and a dihalogenated aromatic compound with an organic polar solvent of 1.25 liters or more per mole of the sulfur component of the sulfidizing agent 8. The polyarylene sulfide according to any one of items 1 to 7, wherein polyarylene sulfide obtained by separating oligoarylene sulfide from a mixture containing sulfide is used as polyarylene sulfide (a). And oligoarylene sulfide separation method.
10. At least a reaction mixture composed of polyarylene sulfide, a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent is heated using 1.25 liters or more of an organic polar solvent with respect to 1 mol of a sulfur component in the reaction mixture. From the first item, wherein the polyarylene sulfide obtained by separating the oligoarylene sulfide from the mixture containing the polyarylene sulfide and the oligoarylene sulfide obtained by the reaction is used as the polyarylene sulfide (a). The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of items 7 to 9.
11. Item 11. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of Items 1 to 10, wherein the organic polar solvent is an organic amide solvent.
12 Item 12. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of Items 1 to 11, wherein the dihalogenated aromatic compound (c) is dichlorobenzene.

  INDUSTRIAL APPLICABILITY According to the present invention, a method for separating polyarylene sulfide and oligoarylene sulfide can be provided. More specifically, a method for producing polyarylene sulfide with reduced impurity components by an economical and simple method, and cyclic oligoarylene sulfide It is possible to provide a method for producing an oligoarylene sulfide mainly composed of

It is a block diagram which shows an example of the separation method of polyarylene sulfide and oligoarylene sulfide in the preferable condition of this invention.

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 production of the polyarylene sulfide and oligoarylene sulfide of the present invention, an organic polar solvent is used as a reaction solvent, 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, caprolactam such as N-methyl-ε-caprolactam and ε-caprolactam. Aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, and mixtures thereof. Is preferably used because of its high stability. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferably used.

  In the present invention, the amount of the organic polar solvent used as the reaction solvent is not particularly limited, and the PAS and oligoarylene sulfide produced by the reaction of the sulfidizing agent with the dihalogenated aromatic compound have the desired characteristics. The amount used can be varied. In general, when a high molecular weight PAS is desired, it is advantageous to reduce the amount of organic polar solvent used. When a low molecular weight PAS is desired, or when an increased amount of oligoarylene sulfide is desired, the organic polar solvent is used. It is preferable to increase the amount of use. The upper limit of the amount of organic polar solvent used is not particularly limited, but from the viewpoint of more efficiently producing polyarylene sulfide and oligoarylene sulfide, the amount of organic polar solvent used is 50 per mol of sulfur component contained in the reaction mixture. It is preferably less than or equal to liters, more preferably less than or equal to 20 liters, and even more preferably less than or equal to 15 liters. The lower limit of the amount of the organic polar solvent used is not particularly limited. However, when it is desired to increase the amount of oligoarylene sulfide produced, the amount of the organic polar solvent used is 1.25 liters or more relative to 1 mol of the sulfur component contained in the reaction mixture. Preferably, it is 1.5 liters or more, more preferably 2 liters or more. Although the yield of oligoarylene sulfide increases when the amount of organic polar solvent used is increased, the production amount of polyarylene sulfide and oligoarylene sulfide per unit volume of the reaction vessel decreases, and the time required for the reaction increases. Since the yield of oligoarylene sulfide decreases and the yield of polyarylene sulfide tends to improve when the amount of organic polar solvent used is reduced, each of polyarylene sulfide and oligoarylene sulfide is produced. It is preferable to set it as the usage-amount range of an organic polar solvent mentioned above from a viewpoint of making a yield and productivity compatible.

(4) Polyarylene sulfide PAS in the present invention is a linear homopolymer or a line containing a repeating unit of the formula:-(Ar-S)-as a main constituent unit, preferably containing 80 mol% or more of the repeating unit. Copolymer. Ar includes units represented by the following formula (A) to formula (B), 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.)

  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 (s) to (ta). 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 A range of ˜500 Pa · s is a preferable range from the viewpoint of easy availability. Further, the molecular weight of PAS is not particularly limited, and general PAS can be used. The weight average molecular weight of such PAS can be exemplified as 2,000 to 1,000,000, 500,000 is preferable, and 5,000 to 100,000 is more preferable. 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.

  The production method of the polyarylene sulfide (a) used in the present invention is not particularly limited, and any production method can be used. For example, an alkali metal sulfide represented by Patent Document 1 described above can be used. It can be obtained by a method of reacting a polyhaloaromatic compound in an organic amide solvent. In addition, it is possible to use a wide range of molded products, molded scraps, waste plastics, off-spec products, etc. using the manufactured PAS.

  In general, the production of polyarylene sulfide and oligoarylene sulfide proceeds simultaneously in the reaction system. In the present invention, such PAS can also be used as a raw material without any problem. For example, an organic polarity of not less than 1.25 liters of a sulfidizing agent and a dihalogenated aromatic compound per 1 mol of the sulfur component of the sulfidizing agent. A method using polyarylene sulfide obtained by separating oligoarylene sulfide from a reaction mixture containing polyarylene sulfide and oligoarylene sulfide obtained by heating and reacting with a solvent is a particularly preferable method. I can say that. Furthermore, polyarylene sulfide produced by the practice of the present invention, that is, at least polyarylene sulfide obtained by contacting at least a polyarylene sulfide, a sulfidizing agent, and a dihalogenated aromatic compound in an organic polar solvent, The use of polyarylene sulfide obtained by separating oligoarylene sulfide from the reaction mixture containing oligoarylene sulfide and alkali metal halide is a particularly preferable method.

  The amount of PAS used is the main structural unit of PAS as long as PAS is contained in the reaction mixture at the start of the reaction, that is, when the conversion rate of the dihalogenated aromatic compound charged in the reaction system is 0. Based on the repeating unit of formula-(Ar-S)-, it is preferably in the range of 0.1-20 repeating unit moles per mole of sulfur component of the sulfiding agent, and in the range of 0.25-15 repeating unit moles. Is more preferable, and the range of 1 to 10 repeating unit moles is still more preferable. When the amount of PAS used is in a preferred range, the reaction tends to proceed in a short time.

  The form of PAS is not particularly limited, and may be a dry powder, powder, granule, or pellet, and may be used in a state containing an organic polar solvent as a reaction solvent. It is also possible to use in a state containing a third component that does not inhibit the reaction. Examples of such a third component include inorganic fillers, and PAS in the form of a resin composition containing inorganic fillers can also be used.

(5) 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 formula (A) to formula (B), 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 (h) containing 80 mol% or more of the repeating unit.

Here, examples of Ar can include units represented by the formulas (a) to (b). Among them, the formulas (a) to (c) are preferable, and the formulas (a) and (b) are more preferable. Of these, formula (a) is particularly preferred.

  In the cyclic oligoarylene sulfide, the repeating units such as the above formulas (a) to (si) may be included randomly, in blocks, or any mixture thereof. 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 (h) 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.

(6) Alkali metal halides The alkali metal halides in the present invention are those produced by the reaction of a sulfiding agent and a dihalogenated aromatic compound, those produced by the reaction of other components in the reaction system, sulfides 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.

(7) Production method of polyarylene sulfide and oligoarylene sulfide In the present invention, at least (a) polyarylene sulfide, (b) sulfidizing agent, and (c) dihalogenated aromatic compound are contacted in an organic polar solvent. Reaction is performed to produce a reaction mixture comprising polyarylene sulfide and oligoarylene sulfide.

  In the production of the PAS and oligoarylene sulfide of the present invention, it is preferable to heat the reaction mixture composed of the above components beyond the reflux temperature under normal pressure of the reaction mixture. Here, the normal pressure is a pressure in the vicinity of the standard state of the atmosphere, and is an atmospheric pressure condition in which the temperature is approximately 25 ° C. and the absolute pressure is approximately 101 kPa. The reflux temperature is a temperature at which the liquid component of the reaction mixture repeats boiling and condensation. Examples of the method for bringing the reaction mixture into a heated state exceeding the reflux temperature under normal pressure include a method of reacting the reaction mixture under a pressure exceeding normal pressure and a method of heating the reaction mixture in a sealed container.

  A more preferable reaction temperature in the production of the PAS and oligoarylene sulfide of the present invention is a temperature at which the polyarylene sulfide (a) used as a raw material melts in the reaction mixture. The polyarylene sulfide (a) as a raw material is generally in a solid state near room temperature, and the reaction system is homogenized by performing the reaction at a temperature at which PAS dissolves. Tend to reduce the time required for This temperature cannot be uniquely determined because it varies depending on the type and amount of components in the reaction mixture, the structure of the polyarylene sulfide (a) used as a raw material, the molecular weight, etc., but usually 120 to 350 ° C., preferably The range of 200-320 degreeC, More preferably, 230-300 degreeC, More preferably, 240-280 degreeC can be illustrated. In this preferred temperature range, a higher reaction rate can be obtained, and the reaction tends to be uniform and easy to proceed, and the generated PAS component tends not to be decomposed, so that the PAS component can be efficiently obtained. It is in. The reaction may be 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.

  The reaction time depends on the structure and molecular weight of the polyarylene sulfide (a) used as a raw material, the sulfidizing agent, the dihalogenated aromatic compound, the organic polar solvent, the amount of these raw materials, and the reaction temperature. Although it cannot be generally defined, since the method of the present invention has a characteristic that an extremely high reaction rate is easily obtained, the reaction proceeds sufficiently even within 10 hours, preferably within 6 hours, more preferably within 3 hours. . The lower limit of the reaction time is not particularly limited, but is preferably 0.1 hour or longer, more preferably 0.5 hour or longer, and by setting this preferred time or longer, unreacted raw material components tend to be sufficiently reduced. .

  In the production of the PAS and oligoarylene sulfide of the present invention, the pressure at which the reaction mixture is heated is not particularly limited, but is preferably a pressure that can exceed the reflux temperature of the reaction mixture under normal pressure. Although the pressure when heating the reaction mixture varies depending on the raw materials constituting the reaction mixture and its composition, reaction temperature, etc., it cannot be uniquely defined, but the upper limit of the preferred pressure is 10 MPa or less, more preferably 5 MPa or less Can be illustrated. Moreover, as a minimum of a preferable pressure, 0.05 MPa or more, More preferably, 0.3 MPa or more, More preferably, 0.4 MPa or more can be illustrated by a gauge pressure. In such a preferable pressure range, the time required for producing PAS and oligoarylene sulfide tends to be shortened. When the amount of the organic polar solvent used in the production of PAS and oligoarylene sulfide is increased, that is, the polyarylene sulfide (a), the sulfidizing agent (b) and the dihalogenated aromatic compound (c) which are raw materials in the reaction mixture The effect of carrying out the reaction in the preferred pressure range tends to be particularly large under the condition where the concentration of is low, and the raw material consumption rate tends to be further improved. The reason for this is not clear at the present time, but in the production of PAS and oligoarylene sulfide, raw materials such as dihalogenated aromatic compounds that are volatile under the heating conditions in the reaction are partly present in the gas phase in the reaction system, The reaction with the reaction substrate in the liquid phase portion may not easily proceed, and volatilization in the reaction system of such raw materials can be suppressed by setting the above-mentioned preferable pressure range, so the reaction proceeds more efficiently. I guess it will be. Further, in order to set the pressure at the time of heating the reaction mixture to the above preferable pressure range, the reaction mixture is reacted with an inert gas described later at an optional stage such as before starting the reaction or during the reaction, preferably before starting the reaction. It is also a preferable method to pressurize the system. Here, the gauge pressure is a relative pressure based on the atmospheric pressure, and is equivalent to a pressure value obtained by subtracting the atmospheric pressure from the absolute pressure.

  In the method for producing PAS and oligoarylene sulfide of the present invention, (a) polyarylene sulfide, (b) a sulfidizing agent, (c) a dihalogenated aromatic compound, and an organic polar solvent are charged in a reactor, and these are essential. Reaction is performed as a component. The order in which these essential components are charged into the reactor is not particularly limited, but a method of first charging all or a part of the organic polar solvent to be used and then charging the other components is preferable for homogenizing the reaction mixture. In addition to the essential components, a third component that does not significantly inhibit the reaction and a third component that has an effect of accelerating the reaction can be added to the reaction mixture. Although there is no restriction | limiting in particular in the method of performing reaction, Performing on stirring conditions is preferable for homogenization of a reaction system. In addition, there is no restriction | limiting in particular in the temperature at the time of charging the said raw material here, For example, you may react after charging a raw material near room temperature, or you may supply a raw material to the reactor temperature-controlled beforehand to the temperature preferable for reaction mentioned above. It is also possible to carry out the reaction by charging. It is also possible to continuously carry out the reaction by sequentially charging the raw material into the reaction system in which the reaction is performed.

Further, when PAS and oligoarylene sulfide are produced, it is possible to use one containing water as an organic polar solvent. In general, in the reaction using a sulfidizing agent and a dihalogenated aromatic compound, the reaction rate tends to decrease as the amount of water in the reaction mixture increases. Since the reaction proceeds very quickly, it is possible to perform a sufficient reaction without strictly controlling the amount of water in the reaction mixture. Therefore, the amount of water in the reaction mixture of the present invention is not particularly limited, but at the time when the reaction starts, that is, when the conversion rate of the dihalogenated aromatic compound (hereinafter sometimes abbreviated as DHA) charged to the reaction system is zero. The water content can be exemplified as a preferable range of 0.2 mol or more and 20 mol or less per mol of sulfur component in the reaction mixture, preferably 0.5 mol or more and 10 mol or less, 0.6 mol or more and 8 mol or less. Is more preferable. If the sulfidizing agent, organic polar solvent, dihalogenated aromatic compound, PAS and other components that form the reaction mixture contain water and the amount of water in the reaction mixture exceeds the above range, before starting the reaction In the middle of the reaction, it is possible to reduce the amount of water in the reaction system so that the amount of water is within the above range, and this tends to yield PAS and oligoarylene sulfide efficiently in a short time. . In addition, when the water content of the reaction mixture is less than the above preferable range, it is also a preferable method to add water so that the above water content is obtained. The conversion rate of DHA is a value calculated by the following formula. The remaining amount of DHA can be usually determined by gas chromatography.
(A) When dihalogenated aromatic compound is added excessively 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 (%) = [[DHA charge (mol) -DHA remaining amount (mol)] / [DHA charge (mol)]] × 100%

  Furthermore, in the production of PAS and oligoarylene sulfide, at any stage where the raw materials charged by continuing the reaction for a desired time are reduced, one or more of PAS, sulfidizing agent, dihalogenated aromatic compound and organic polar solvent are used. It is also possible to continue the reaction by adding.

  As described above, the additional addition of PAS, sulfidizing agent and dihalogenated aromatic compound allows an optional stage in which the charged raw materials are reduced, but the DHA conversion rate is 50% or more. 70% or more is more preferable, and the PAS component can be obtained more efficiently by adding at such a stage.

  In addition, when the amount of water in the reaction mixture changes due to the addition of the raw material, it is also possible to perform an additional operation so as to achieve the above-described preferable amount of water. It is also desirable to later remove any amount of water from the reaction mixture. In the removal of water, when components other than water are removed from the reaction mixture, a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent can be further added as necessary. The operation of returning the components to the reaction mixture may be performed again.

  In the production of the PAS and oligoarylene sulfide of the present invention, various known polymerization methods and reaction methods such as a batch method and a continuous method can be employed. Further, the atmosphere in the production is preferably a non-oxidizing atmosphere, and it is preferably carried out in an inert gas atmosphere such as nitrogen, helium, and argon. In particular, from the viewpoint of economy and ease of handling, the nitrogen atmosphere is preferable. preferable. 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) Separation method of polyarylene sulfide and oligoarylene sulfide In the present invention, polyarylene sulfide and oligoarylene sulfide are separated from a reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent. Solid-liquid separation (B) in a temperature range where polyarylene sulfide is not dissolved and oligoarylene sulfide is soluble, or solid-liquid separation (A) at a temperature sufficient to dissolve polyarylene sulfide. To obtain a filtrate component containing polyarylene sulfide, oligoarylene sulfide and an organic polar solvent, and then subjecting the filtrate component to a temperature at which polyarylene sulfide does not dissolve, and further subjecting the filtrate component to solid-liquid separation (B) It is characterized by that. Hereinafter, solid-liquid separation (A) and solid-liquid separation (B) will be described in detail.

<Solid-liquid separation (A)>
In solid-liquid separation (A), PAS dissolves in a reaction mixture obtained by reacting at least (a) polyarylene sulfide, (b) sulfidizing agent, and (c) dihalogenated aromatic compound in an organic polar solvent. The solid component is separated at a temperature sufficient to recover a soluble component, that is, a solution component containing polyarylene sulfide, oligoarylene sulfide and an organic polar solvent, as a filtrate.

  Here, the temperature at which the solid-liquid separation is performed is not particularly limited as long as the polyarylene sulfide is dissolved, but the upper limit 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. Further, in the case of the polyarylene sulfide having the above preferred weight average molecular weight, the temperature is preferably higher than 200 ° C., more preferably 220 ° C. or higher, and further 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.

  Although there is no restriction | limiting in the pressure at the time of performing solid-liquid separation (A), 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.

  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 performed according to the preferred conditions employed for the solid-liquid separation (A) described above.

<Solid-liquid separation (B)>
In the present invention, the filtrate component obtained by solid-liquid separation (A) or at least (a) polyarylene sulfide, (b) sulfidizing agent, and (c) dihalogenated aromatic compound are reacted in an organic polar solvent. The resulting reaction mixture is subjected to the following solid-liquid separation (B).

  In the solid-liquid separation (B), the polyarylene sulfide is not dissolved and the solid-liquid separation is performed in a temperature range in which the oligoarylene sulfide is soluble. The preferable upper limit temperature is 200 ° C. or less, more preferably 150 ° C. Hereinafter, more preferably, 120 degrees C or less can be illustrated. 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, the oligoarylene sulfide component contained in the reaction mixture or the filtrate obtained by solid-liquid separation (A) in this preferred temperature range has a strong tendency to be soluble in an organic polar solvent. Oligoarylene sulfide has a strong tendency to dissolve in organic polar solvents under these conditions. Therefore, under the conditions for performing solid-liquid separation (B), the filtrate obtained by the reaction mixture or solid-liquid separation (A) becomes a slurry containing solid PAS. As solids, on the other hand, the oligoarylene sulfide is separated as a solution-like filtrate. In addition, as a minimum temperature in the case of solid-liquid separation (B), 10 degreeC or more can be illustrated, 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 when performing solid-liquid separation (B), and for example, the pressure range in solid-liquid separation (A) can be exemplified, but solid-liquid separation (B) is lower than solid-liquid separation (A). Since the solid-liquid separation operation is performed at the temperature, the operation can be performed under a pressure lower than that of the solid-liquid separation (A). 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 solid-liquid separation (A) can be employed. Pressure filtration or vacuum filtration, which 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 this solid-liquid separation (B) operation, that is, the mesh diameter or the pore diameter depending on the solid content present in the slurry subjected to the solid-liquid separation (B) It is effective to select the filter pore size. The average particle diameter (median diameter) of PAS in the slurry subjected to solid-liquid separation (B) 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 reaction mixture or the filtrate obtained by solid-liquid separation (A) can be separated as a solid content, preferably 80% or more, more preferably 90% or more, more preferably 95% or more 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. Although it can illustrate, it is preferable to perform the conditions which perform these operation according to the preferable conditions employ | adopted for above-mentioned solid-liquid separation (B). In addition, the solvent used here should just be what can melt | dissolve an oligoarylene sulfide, Preferably an organic polar solvent can be illustrated.

(9) Other post-processing 1
In the present invention, at least (a) polyarylene sulfide, (b) a sulfidizing agent, and (c) a reaction mixture obtained by reacting a dihalogenated aromatic compound in an organic polar solvent is subjected to solid-liquid separation (B). Thus, PAS can be obtained as a solid component. The solid component thus obtained has a significantly reduced oligomer content. In this case, since the solid component contains an alkali metal halide, the alkali metal halide can be removed by a known method. Examples of the removal method include a method of contacting with a second solvent in which the alkali metal halide is soluble.

  As the second solvent used when removing the alkali metal halide from the solid component, a solvent in which the alkali metal halide is soluble is preferable. For example, alcohol solvents such as methanol and ethanol, and water can be exemplified. Particularly preferred.

  The temperature is not particularly limited, but the upper limit is preferably set to the reflux condition temperature or lower under normal pressure of the second solvent to be used. When using the above-described solvent, for example, 20 to 100 ° C. can be exemplified as a preferable temperature range, More preferably, 25-80 degreeC can be illustrated.

  As a method of bringing the solid component into contact with the second solvent, a method in which the second solvent is added to the solid component-laminated filter and solid-liquid separation is performed, or the second solvent is added to the solid component and stirred. For example, a method of solid-liquid separation after slurrying with a slurry can be exemplified. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. It is also possible to reduce the alkali metal halide content by bringing the polyarylene sulfide thus obtained into contact with the second solvent again.

  Since the polyarylene sulfide thus obtained contains the second solvent, it can be dried at normal pressure and / or under 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.

(10) Other post-processing 2
In the present invention, PAS can be obtained as a solid component by subjecting the filtrate component obtained by solid-liquid separation (A) to solid-liquid separation (B).

  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 in which the solid component is heated and filtered preferably at 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.

(11) Other post-processing 3
By the solid-liquid separation (B), an oligoarylene sulfide can be obtained as a filtrate component (which may contain a solid component depending on the temperature).

  It is also possible to recover the oligoarylene sulfide as a solid content by removing the organic polar solvent from the filtrate component as desired. Examples of the method for removing the organic polar solvent include a method of removing by distillation, a method of contacting with a third solvent miscible with the organic polar solvent, and the like.

  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 manner, using a third solvent described later, whereby the ionic compound or organic polar solvent remaining in the oligoarylene sulfide is removed. It tends to be further reduced.

  As a specific method for obtaining oligoarylene sulfide by solvent replacement of the filtrate component with a third solvent, the oligoarylene sulfide is not dissolved, or it is contacted with a third solvent in which 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 third 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 for contacting the filtrate component and the third solvent is a pressure condition that requires an expensive pressure vessel. Should be avoided. As the preferred solvent as the third solvent, those which do not substantially cause undesirable side reactions such as decomposition and crosslinking of oligoarylene sulfide are preferable. 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 third solvent, but the upper limit temperature is preferably set to the reflux condition temperature under the normal pressure of the third 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 during which the filtrate component is brought into contact with the third solvent cannot be uniquely limited because it varies depending on the type of solvent used, the temperature, and the like, but can be exemplified by, for example, 1 minute to 50 hours.

  As a method of bringing the filtrate component into contact with the third solvent, a method of adding the third solvent to the filtrate component and stirring and mixing as necessary, while stirring the filtrate component in the third 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 third 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. When the organic polar solvent, alkali metal halide, sulfiding agent, dihaloaromatic compound remains in the oligoarylene sulfide obtained after the solid-liquid separation, the obtained oligoarylene sulfide and the third solvent are added again. These can be further reduced by contact.

  Since the oligoarylene sulfide thus obtained contains the third solvent used for contact with the filtrate components, 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.

(12) Produced polyarylene sulfide PAS obtained by the present invention is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and not only for injection molding, injection compression molding and blow molding, By extrusion molding, it can be formed into extruded products such as sheets, films, 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, various valves such as IC regulator, 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.

(13) Generated oligoarylene sulfide The oligoarylene sulfide obtained by the method of the present invention usually has a purity containing 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more of cyclic oligoarylene sulfide. It is expensive and has high utility value even industrially having characteristics different from the generally obtained linear PAS. In addition, the cyclic oligoarylene sulfide obtained by the production method of the present invention is characterized in that m in the formula (h) is not single and the formula (h) having m of 4 to 50 is easily obtained. Have Here, a preferable range of m is 4 to 25, and more preferably 4 to 20. When m is in this range, as will be described later, when cyclic PAS is used for ring-opening polymerization, the polymerization reaction tends to proceed, and a high molecular weight product tends to be easily obtained. The reason for this is not clear at this time, but it is assumed that cyclic PAS in this range has a large bond distortion due to the fact that the molecule is cyclic, and that a ring-opening reaction easily occurs during polymerization.

  In addition, since cyclic PAS having a single m is obtained as a single crystal, it has a very high melting temperature. However, in the present invention, cyclic PAS is easy to obtain a mixture having different m, and thus melting of cyclic PAS There is a feature that the temperature is low, which expresses an excellent feature that, for example, the heating temperature when the cyclic PAS is melted and used can be lowered.

  The present invention will be specifically described below with reference to 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>
The alkali metal content contained in PAS and oligoarylene sulfide sulfide was determined 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 adjusted to a constant volume 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]
Here, an example is shown in which PAS is produced according to the prior art, that is, PAS is produced by bringing a sulfidizing agent and a dihalogenated aromatic compound into contact with each other in an organic polar solvent.

  In a stainless steel autoclave equipped with a stirrer, 116.9 g (1.00 mol) of a 48 wt% aqueous solution of sodium hydrosulfide, 43.8 g (1.05 mol) of 96% sodium hydroxide, N-methyl-2-pyrrolidone (NMP) 198.3 g (2.00 mol), 8.2 g (0.10 mol) of sodium acetate, and 150 g of ion-exchanged water were charged. After attaching the rectifying column to the autoclave, stirring was started at 240 rpm, and the mixture was gradually heated to an internal temperature of 235 ° C. over about 3 hours while passing nitrogen at normal pressure. During this time, 212 g was distilled out of the rectification column. The amount of hydrogen sulfide scattered was 0.012 mol. In addition, as a result of analyzing the distillate by gas chromatography, it was found to be a mixed solution of 209 g of water and 3.5 g of NMP, and the amounts of water and NMP in the reaction system were 2.3 g and 194.8 g, respectively. .

  After completion of the distillation, the reaction vessel was cooled to about 160 ° C., and 148.5 g (1.01 mol) of p-dichlorobenzene (p-DCB) and 99.1 g (1.00 mol) of NMP were further added. Was sealed under nitrogen gas. While stirring at 400 rpm, the temperature was raised to 200 ° C. over about 30 minutes, and then the temperature was raised from 200 ° C. to 270 ° C. at a rate of 0.6 ° C./minute, and the reaction was continued at 270 ° C. for 140 minutes. Thereafter, 36 g (2.00 mol) of water was poured into the system while cooling to 250 ° C. over 15 minutes, and then cooled from 250 ° C. to 220 ° C. at a rate of 0.4 ° C./min. Thereafter, it was rapidly cooled to near room temperature.

  The contents were taken out, diluted with 500 g of NMP to form a slurry, and stirred at 85 ° C. for about 30 minutes, and then the slurry was filtered through a stainless 80 mesh sieve to recover the solid content. 400 g of NMP was added to the obtained solid content, and the mixture was stirred at 85 ° C. for about 30 minutes, followed by filtration in the same manner to recover the solid content. Thereafter, the operations of stirring, washing and filtering with 800 g of warm water were repeated 5 times to obtain a granular solid. This was dried with hot air at 60 ° C. and then dried under reduced pressure at 120 ° C. to obtain about 90 g of a dry solid.

  As a result of analyzing the solid thus obtained, it was found from the absorption spectrum in infrared spectroscopic analysis (apparatus; FTIR-8100A manufactured by Shimadzu Corp.) that it was a linear polyphenylene sulfide. The weight average molecular weight was 38,600. The polyphenylene sulfide obtained here is hereinafter referred to as PPS-1.

[Reference Example 2]
Here, PAS and oligoarylene sulfide obtained by heating and reacting a sulfiding agent and a dihalogenated aromatic compound with an organic polar solvent of 1.25 liters or more per mole of the sulfur component of the sulfiding agent. An example in which a PAS having a molecular weight lower than that of Reference Example 1 was produced by a method of separating oligoarylene sulfide from a PAS mixture containing benzene was shown.

  A stainless steel autoclave equipped with a stirrer was charged with 14.03 g (0.120 mol) of a 48 wt% aqueous solution of sodium hydrosulfide and 12.50 g (0.144 mol) of a 48 wt% aqueous solution prepared using 96% sodium hydroxide. ), 615.0 g (6.20 mol) of NMP, and 17.99 g (0.122 mol) of p-DCB. After sufficiently substituting the inside of the reaction vessel with nitrogen, the inside of the reaction system was pressurized to 0.3 MPa (gauge pressure) with nitrogen.

  While stirring at 400 rpm, the temperature was raised from room temperature to 200 ° C. over about 25 minutes. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 35 minutes. The pressure in the reaction system at this stage was 1.3 MPa as a gauge pressure. After maintaining at 250 ° C. for 2 hours, the contents were recovered after quenching to near room temperature.

  500 g of the obtained content was diluted with about 1500 g of ion-exchanged water, and then filtered through a glass filter having an average opening of 10 to 16 micrometers. The filter-on component was dispersed in about 300 g of ion-exchanged water, stirred at 70 ° C. for 30 minutes, and filtered again in the same manner three times to obtain a white solid. This was vacuum dried at 80 ° C. overnight to obtain a dry solid.

The obtained solid matter was charged into a cylindrical filter paper, and Soxhlet extraction was performed for about 5 hours using chloroform as a solvent to remove low molecular weight components contained in the solid content.
The solid component remaining in the cylindrical filter paper after the extraction operation was dried under reduced pressure at 70 ° C. overnight to obtain about 6.98 g of an off-white solid. As a result of the analysis, it was a linear polyphenylene sulfide and the weight average molecular weight was 6,300 from the absorption spectrum in the infrared spectroscopic analysis. The polyphenylene sulfide obtained here is hereinafter referred to as PPS-2.

[Reference Example 3]
Here, polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent obtained by heating polyarylene sulfide (PPS-1), a sulfidizing agent and a dihalogenated aromatic compound in an organic polar solvent are used. The preparation of the reaction mixture containing is described.

  In a stainless steel autoclave equipped with a stirrer, 10.37 g (0.0960 mol of sulfur component amount) of PPS-1 obtained in Reference Example 1 and 2.817 g of a 48 wt% aqueous solution of sodium hydrosulfide (1. 345 g (0.0240 mol), 1.472 g (0.0818 mol) of water), 2.500 g of a 48 wt% aqueous solution prepared with sodium hydroxide having a purity of 96% (1.200 g of sodium hydroxide (0.0300 mol)), 1.300 g (0.0722 mol) of water), 615.0 g (6.20 mol) of N-methyl-2-pyrrolidone (NMP), and 3.528 g (0.0240 mol) of p-dichlorobenzene (p-DCB) were charged. . The total amount of sulfur components derived from PPS-1 and sodium hydrosulfide was 0.120 mol, and the amount of solvent per mol of sulfur component in the reaction mixture was about 5.0 L.

  After sufficiently substituting the inside of the reaction vessel with nitrogen, the inside of the reaction system was pressurized to 0.3 MPa (gauge pressure) with nitrogen. While stirring at 400 rpm, the temperature was raised from room temperature to 200 ° C. over about 25 minutes. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 35 minutes. The pressure in the reaction system at this stage was 1.0 MPa as a gauge pressure. After holding at 250 ° C. for 1 hour, the contents were recovered after quenching to near room temperature.

[Reference Example 4]
Here, polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent obtained by heating polyarylene sulfide (PPS-2), a sulfidizing agent and a dihalogenated aromatic compound in an organic polar solvent are used. The preparation of the reaction mixture containing is described.

  In a stainless steel autoclave equipped with a stirrer, 10.37 g (0.0960 mol of sulfur component amount) of PPS-2 obtained in Reference Example 2 and 2.817 g of a 48 wt% aqueous solution of sodium hydrosulfide (1. 345 g (0.0240 mol), 1.472 g (0.0818 mol) of water), 2.500 g of a 48 wt% aqueous solution prepared with sodium hydroxide having a purity of 96% (1.200 g of sodium hydroxide (0.0300 mol)), 1.300 g (0.0722 mol) of water, 615.0 g (6.20 mol) of N-methyl-2-pyrrolidone (NMP), and 4.410 g (0.0300 mol) of p-dichlorobenzene (p-DCB) were charged. . The total amount of sulfur components derived from PPS-2 and sodium hydrosulfide was 0.120 mol, and the amount of solvent per mol of sulfur component in the reaction mixture was about 5.0 L.

  After sufficiently substituting the inside of the reaction vessel with nitrogen, the inside of the reaction system was pressurized to 0.3 MPa (gauge pressure) with nitrogen. While stirring at 400 rpm, the temperature was raised from room temperature to 200 ° C. over about 25 minutes. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 35 minutes. The pressure in the reaction system at this stage was 1.0 MPa as a gauge pressure. After maintaining at 250 ° C. for 1 hour, the contents were recovered after quenching to near room temperature.

[Example 1]
Here, a method for separating polyphenylene sulfide and oligophenylene sulfide by subjecting the reaction mixture obtained in Reference Example 3 to solid-liquid separation (A) and solid-liquid separation (B) will be exemplified.

<Solid-liquid separation (A)>
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, 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 recovered while pressurizing the inside of the container with nitrogen at the stage when the filtration rate was lowered. By this operation, about 99 g of filtrate and about 0.55 g of solid content were recovered.

<Solid-liquid separation (B)>
The filtrate obtained by solid-liquid separation (A) was heated to 100 ° C. At this stage, the filtrate obtained by solid-liquid separation (A) 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 2.1 g of solid content and about 97 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 vacuum dried at 70 ° C. overnight, and about 1.4 g of dry solid (68% yield on the assumption that all sulfur components present in the reaction system during the reaction were converted to PPS components) Got.
As a result of analyzing the solid thus obtained, it was determined that the polymer was a polymer (PPS) composed of phenylene sulfide units from the absorption spectrum in infrared spectroscopic analysis, and was a polymer having a weight average molecular weight of 6,400 based on GPC measurement. all right. The low molecular compound content was 0.25% by weight, the alkali metal content was 140 ppm, and it was found that the PPS was extremely high in purity.

<Recovery of oligoarylene sulfide>
The filtrate component obtained by solid-liquid separation (B) was dropped into about 8 times the amount of deionized water and the deionized water insoluble component deposited was filtered using a filter paper having an average pore size 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, and about 0.61 g of dry solid (30% when assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) Got.

  As a result of analyzing the solid thus obtained, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and is an oligomer having a weight average molecular weight of 1,000 based on GPC measurement. I understood. In addition, this white powder is a cyclic oligo having 4 to 12 repeating units based on mass spectral analysis of the components separated by high performance liquid chromatography (apparatus; Hitachi M-1200H) and molecular weight information by MALDI-TOF-MS. It was a mixture containing phenylene sulfide as a main component, and the weight fraction of cyclic oligophenylene sulfide was found to be about 80% and high purity cyclic oligoarylene sulfide.

[Example 2]
Here, the reaction mixture obtained in Reference Example 4 was reacted using PPS having a molecular weight of 6,300 and a lower molecular weight than that of Reference Example 3 as a raw material. An example of a method for separating polyphenylene sulfide and oligophenylene sulfide by the above method is described.

<Solid-liquid separation (A)>
100 g of the reaction solution obtained in Reference Example 4 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 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 recovered while pressurizing the inside of the container with nitrogen at the stage when the filtration rate was lowered. By this operation, about 99 g of filtrate and about 0.54 g of solid content were recovered.

<Solid-liquid separation (B)>
The filtrate obtained by solid-liquid separation (A) was heated to 100 ° C. The filtrate obtained by solid-liquid separation (A) at this stage was 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 2.0 g of solid content and about 97 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, and about 1.4 g of dry solid (yield on the assumption that all sulfur components present in the reaction system during the reaction were converted to PPS components was 67%) Got.

  As a result of analyzing the solid obtained in this manner, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and a polymer having a weight average molecular weight of 6,300 based on GPC measurement. all right. The low molecular compound content was 0.25% by weight, the alkali metal content was 140 ppm, and it was found that the PPS was extremely high in purity.

<Recovery of oligoarylene sulfide>
The filtrate component obtained by solid-liquid separation (B) was dropped into about 8 times the amount of deionized water and the deionized water insoluble component deposited was filtered using a filter paper having an average pore size of 1 μm to obtain a solid content. . The work of obtaining the solid content by dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to repeat was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight, and about 0.62 g of dried solid (30% yield assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) )

  As a result of analyzing the solid thus obtained, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and is an oligomer having a weight average molecular weight of 1,000 based on GPC measurement. I understood. Moreover, this white powder is a cyclic oligo having 4 to 12 repeating units based on mass spectral analysis of the components divided by high performance liquid chromatography (apparatus; Hitachi M-1200H) and molecular weight information by MALDI-TOF-MS. It was a mixture containing phenylene sulfide as a main component, and the weight fraction of cyclic oligophenylene sulfide was found to be about 78%, which is a highly pure cyclic oligoarylene sulfide.

[Example 3]
Here, regarding the method of subjecting the reaction mixture obtained in Reference Example 4 to solid-liquid separation (A) and solid-liquid separation (B) to separate polyphenylene sulfide and oligophenylene sulfide, the temperature of solid-liquid separation temperature (B) Was performed at a higher temperature than in Example 2.

<Solid-liquid separation (A)>
100 g of the reaction solution obtained in Reference Example 4 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 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 recovered while pressurizing the inside of the container with nitrogen at the stage when the filtration rate was lowered. By this operation, about 99 g of filtrate and about 0.55 g of solid content were recovered.

<Solid-liquid separation (B)>
The filtrate obtained by solid-liquid separation (A) was heated to 150 ° C. The filtrate obtained by solid-liquid separation (A) at this stage was 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 1.6 g of solid content and about 98 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, and about 1.2 g of dried solid (57% assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) Got.

  As a result of analyzing the solid thus obtained, it was determined that the polymer was a polymer (PPS) composed of phenylene sulfide units from the absorption spectrum in infrared spectroscopic analysis, and was a polymer having a weight average molecular weight of 6,400 based on GPC measurement. all right. The low molecular compound content was 0.21% by weight, the alkali metal content was 130 ppm, and it was found that the PPS was extremely high in purity.

  It was found that by increasing the temperature of the solid-liquid separation (B), a high-purity PPS with a lower content of low-molecular compounds was obtained, although the yield decreased.

<Recovery of oligoarylene sulfide>
The filtrate component obtained by solid-liquid separation (B) was dropped into about 8 times the amount of deionized water and the deionized water insoluble component deposited was filtered using a filter paper having an average pore size of 1 μm to obtain a solid content. . The work of obtaining the solid content by dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to repeat was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight, and about 0.82 g of dry solid (40% yield assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) )

  As a result of analyzing the solid thus obtained, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and is an oligomer having a weight average molecular weight of 1,000 based on GPC measurement. I understood. In addition, this white powder is a cyclic oligo having 4 to 12 repeating units based on mass spectral analysis of the components separated by high performance liquid chromatography (apparatus; Hitachi M-1200H) and molecular weight information by MALDI-TOF-MS. It was a mixture containing phenylene sulfide as a main component, and was found to be a cyclic oligoarylene sulfide having a weight fraction of cyclic oligophenylene sulfide of about 64%.

[Example 4]
Here, regarding the method of subjecting the reaction mixture obtained in Reference Example 4 to solid-liquid separation (A) and solid-liquid separation (B) to separate polyphenylene sulfide and oligophenylene sulfide, the temperature of solid-liquid separation temperature (B) Was carried out at a temperature lower than that in Example 2.

<Solid-liquid separation (A)>
100 g of the reaction solution obtained in Reference Example 4 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 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 recovered while pressurizing the inside of the container with nitrogen at the stage when the filtration rate was lowered. By this operation, about 99 g of filtrate and about 0.55 g of solid content were recovered.

<Solid-liquid separation (B)>
The filtrate obtained by solid-liquid separation (A) was heated to 50 ° C. The filtrate obtained by solid-liquid separation (A) at this stage was 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 2.2 g of solid content and about 97 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, and about 1.4 g of dry solid (69% yield assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) Got.

  As a result of analyzing the solid obtained in this manner, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and a polymer having a weight average molecular weight of 6,300 based on GPC measurement. all right. The low molecular compound content was 0.33% by weight, and the alkali metal content was 170 ppm, indicating that the PPS was extremely high in purity.

<Recovery of oligoarylene sulfide>
The filtrate component obtained by solid-liquid separation (B) was dropped into about 8 times the amount of deionized water and the deionized water insoluble component deposited was filtered using a filter paper having an average pore size of 1 μm to obtain a solid content. . The process of dispersing the obtained solid content in 100 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain a solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight and about 0.58 g of dry solid (29% yield assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) )

  As a result of analyzing the solid thus obtained, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and is an oligomer having a weight average molecular weight of 1,000 based on GPC measurement. I understood. In addition, this white powder is a cyclic oligo having 4 to 12 repeating units based on mass spectral analysis of the components separated by high performance liquid chromatography (apparatus; Hitachi M-1200H) and molecular weight information by MALDI-TOF-MS. It was a mixture containing phenylene sulfide as a main component, and was found to be a cyclic oligoarylene sulfide having a weight fraction of cyclic oligophenylene sulfide of about 90%.

  It was found that by reducing the temperature of the solid-liquid separation (B), the cyclic oligophenylene sulfide having higher purity can be obtained although the yield is lowered.

[Example 5]
Here, the case where solid-liquid separation (A) is not performed in the recovery of the reaction mixture obtained in Reference Example 4 is illustrated.

<Solid-liquid separation (B)>
100 g of the reaction mixture obtained in Reference Example 4 was heated to 100 ° C. and stirred. The reaction mixture was subjected to suction filtration with heat through a PTFE filter (average pore size 1 μm). By this operation, about 2.6 g of solid content and about 97 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, and about 1.4 g of dry solid (yield on the assumption that all sulfur components present in the reaction system during the reaction were converted to PPS components was 67%) Got.

  As a result of analyzing the PPS thus obtained, it was found to be a polymer having a weight average molecular weight of 6,300. The low molecular content was 0.32% by weight, the alkali metal content was 2,800 ppm, and it was found that the PPS was a high purity PPS with a reduced low molecular content. In order to obtain a PPS having a higher purity and a reduced alkali metal content, it was found that the solid-liquid separation of (A) is a more preferable condition.

<Recovery of oligoarylene sulfide>
The filtrate component obtained by solid-liquid separation (B) was dropped into about 8 times the amount of deionized water and the deionized water insoluble component deposited was filtered using a filter paper having an average pore size 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, and about 0.62 g of dry solid (30% when assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components) Got.

  As a result of analyzing the solid thus obtained, it is a polymer (PPS) composed of phenylene sulfide units based on an absorption spectrum in infrared spectroscopic analysis, and is an oligomer having a weight average molecular weight of 1,000 based on GPC measurement. I understood. In addition, this white powder is a cyclic oligo having 4 to 12 repeating units based on mass spectral analysis of the components separated by high performance liquid chromatography (apparatus; Hitachi M-1200H) and molecular weight information by MALDI-TOF-MS. It was a mixture containing phenylene sulfide as a main component, and the weight fraction of cyclic oligophenylene sulfide was about 78%, and it was found that highly pure cyclic oligophenylene sulfide was obtained.

[Comparative Example 1]
Here, the case where solid-liquid separation (B) is not performed in the recovery of the reaction mixture obtained in Reference Example 4 is illustrated.

  Using 100 g of the reaction solution obtained in Reference Example 4, the same procedure as in Example 2 was carried out until solid-liquid separation (A), and the filtrate component obtained in solid-liquid separation (A) was added about 3 times as much deionized water. The deionized water-insoluble component deposited by dripping onto the filter was filtered using 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 300 g of ion-exchanged water, stirring at 70 ° C. for 30 minutes and filtering to obtain a solid content was repeated three times. The obtained solid was subjected to vacuum drying at 70 ° C. overnight, and about 2.0 g of dried solid (yield assuming that all sulfur components present in the reaction system during the reaction were converted to PPS components was 97%) Got. As a result of analyzing the PPS thus obtained, it was found to be a polymer having a weight average molecular weight of 4,800. The low molecular content was 25% by weight and the alkali metal content was 190 ppm. It was found that solid-liquid separation (B) is essential in order to obtain high-purity PPS with a low molecular content.

[Comparative Example 2]
Here, an example is shown in which a reaction mixture containing polyphenylene sulfide, oligophenylene sulfide, and alkali metal halide is prepared by a general technique, and a PPS component (a mixture of PPS and oligophenylene sulfide) is recovered from this reaction mixture.

  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 (1.00 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.

  100 g of the reaction product thus obtained 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 from an absorption spectrum in infrared spectroscopic analysis (apparatus; FTIR-8100A manufactured by Shimadzu Corporation), and a weight average molecular weight of 16, It was found to be 500 polymers. The low molecular compound content was 4.8% by weight, and the alkali metal content was 8,000 ppm. PPS obtained by a general synthesis and recovery method that does not perform the reaction using polyphenylene sulfide as a raw material, solid-liquid separation (A), and solid-liquid separation (B), which is a feature of the present invention, is an extremely large number of low molecular weight compounds. And a metal component.

Claims (12)

At least (a) polyarylene sulfide,
A reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent, obtained by reacting (b) a sulfidizing agent and (c) a dihalogenated aromatic compound in an organic polar solvent, A method for separating polyarylene sulfide and oligoarylene sulfide, wherein the solid-liquid separation (B) is performed in a temperature range in which polyarylene sulfide is not dissolved and oligoarylene sulfide is soluble. At least (a) polyarylene sulfide,
A reaction mixture containing at least polyarylene sulfide, oligoarylene sulfide, alkali metal halide and organic polar solvent, obtained by reacting (b) a sulfidizing agent and (c) a dihalogenated aromatic compound in an organic polar solvent, By performing solid-liquid separation (A) at a temperature sufficient to dissolve the polyarylene sulfide, a filtrate component containing polyarylene sulfide, oligoarylene sulfide and an organic polar solvent is obtained, and then the filtrate component is dissolved in the polyarylene sulfide. A method for separating polyarylene sulfides and oligoarylene sulfides, which is subjected to solid-liquid separation (B) after the temperature is not increased. The method for separating polyarylene sulfide and oligoarylene sulfide according to claim 2, wherein the temperature at which the solid-liquid separation (A) is carried out exceeds 200 ° C. The polyarylene sulfide and the oligoarylene sulfide according to any one of claims 1 to 3, wherein the oligoarylene sulfide is obtained as a solid content from the filtrate component containing the oligoarylene sulfide obtained by the solid-liquid separation (B). Separation method. At least (a) the polyarylene sulfide, (b) the sulfidizing agent, and (c) the organic polar solvent when the dihalogenated aromatic compound is reacted in the organic polar solvent is used in an amount of 50 with respect to 1 mole of the sulfur component in the reaction mixture. The method for separating polyarylene sulfides and oligoarylene sulfides according to any one of claims 1 to 4, wherein the separation is performed in a liter or less. At least (a) the polyarylene sulfide, (b) the sulfidizing agent, and (c) the organic polar solvent when the dihalogenated aromatic compound is reacted in the organic polar solvent, 1 is used per 1 mol of the sulfur component in the reaction mixture. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of claims 1 to 5, wherein 25 liters or more is used. The oligoarylene sulfide obtained as a solid content contains 50 wt% or more of cyclic oligoarylene sulfide having 4 to 50 repeating units represented by the following formula (1). The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of the above.

The polyarylene sulfide obtained by bringing the sulfidizing agent and the dihalogenated aromatic compound into contact with each other in an organic polar solvent is used as the polyarylene sulfide (a). A method for separating the polyarylene sulfide and the oligoarylene sulfide as described. Polyarylene sulfide and oligoarylene obtained by heating and reacting a sulfidizing agent and a dihalogenated aromatic compound with an organic polar solvent of 1.25 liters or more per mole of the sulfur component of the sulfidizing agent The polyarylene sulfide and the oligo according to any one of claims 1 to 7, wherein the polyarylene sulfide obtained by separating the oligoarylene sulfide from the mixture containing sulfide is used as the polyarylene sulfide (a). Separation method of arylene sulfide. At least a reaction mixture composed of polyarylene sulfide, a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent is heated using 1.25 liters or more of an organic polar solvent with respect to 1 mol of a sulfur component in the reaction mixture. The polyarylene sulfide obtained by separating the oligoarylene sulfide from the mixture containing the polyarylene sulfide and the oligoarylene sulfide obtained by the reaction is used as the polyarylene sulfide (a). 8. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of 7 above. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of claims 1 to 10, wherein the organic polar solvent is an organic amide solvent. The method for separating polyarylene sulfide and oligoarylene sulfide according to any one of claims 1 to 11, wherein the dihalogenated aromatic compound (c) is dichlorobenzene.

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