Polyarylene sulfide and method for producing same

Abstract

The present invention can provide: a polyarylene sulfide having a high molecular weight, a low halogen content, and a high purity; and a method for producing same. The present invention relates to a polyarylene sulfide having a weight average molecular weight of 20,000-90,000, a chloroform extraction amount of 0.50% by weight or less, and a halogen terminal ratio of 20% or less with respect to all terminals. The present invention also relates to a method for producing a polyarylene sulfide, in which a sulfidizing agent and a dihalogenated aromatic compound are subjected to a polymerization reaction in an organic polar solvent in the presence of a polymerization stabilizer, the method involving: a step 1 for carrying out the polymerization reaction at 250°C or higher; a step 2 for deliquoring; a step 3 for rinsing a polymer obtained by the polymerization reaction with water, an acid, or both, and subsequently drying same; and a step 4 for rinsing the polymer after drying with an organic solvent.

Description

Polyphenylene Sulfide and Method for Producing the Same 【0001】 The present invention provides a polyphenylene sulfide having high molecular weight, low halogen content, and high purity, and an efficient method for producing the polyphenylene sulfide. 【0002】 Polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) and other polyphenylene sulfides (hereinafter sometimes abbreviated as PAS) have properties suitable as engineering plastics, such as excellent heat resistance, gas barrier properties, moldability, chemical resistance, electrical insulation properties, and heat and humidity resistance. They are used in various electrical and electronic parts, mechanical parts, automotive parts, films, fibers, etc., mainly for injection molding and extrusion molding applications. PAS used in these applications is required to be a high molecular weight PAS due to its excellent mechanical properties, and at the same time, it should have a low halogen content for low environmental impact and high purity to prevent fouling during molding, and high productivity is required. 【0003】 As a method for preparing PAS with a low halogen content, Patent Documents 1 and 2 disclose a method of reducing the halogen content by reacting a terminal blocking agent having a mercapto group or the like with the terminal halogen during the polymerization of PAS. However, the addition of the terminal blocking agent inhibits the increase in the degree of polymerization, making it difficult to increase the degree of polymerization, and a sufficient reaction time for the terminal blocking agent is required, resulting in a decrease in productivity. Further, Patent Document 3 discloses a method of reducing the halogen amount by reacting a mercapto compound with PAS after purification. However, depolymerization occurs during the reaction, resulting in a decrease in molecular weight, and the generated depolymerized product reduces the purity. Furthermore, it is necessary to carry out a separate reaction from the polymerization step, and the productivity is low. Patent Document 4 discloses a method of increasing the purity and reducing the halogen amount through heat treatment after purification. However, it is difficult to significantly reduce the terminal halogen amount by this method, and the reduction of the halogen amount is insufficient. 【0004】Numerous methods for purifying PAS have also been reported. For example, Patent Document 5 discloses a method in which, after the PAS production reaction is complete, the PAS is slowly cooled and granulated, the polymerization liquid is sieved with a mesh, and the solids are washed with an organic solvent and then water. However, the yield is low due to the use of a mesh for filtration, and the washing effect deteriorates as the particle size increases during slow cooling. Patent Document 6 discloses a method in which PAS is recovered by flushing from a high-temperature, high-pressure state into a container at atmospheric pressure, and then washed and dried with water to obtain PAS. This method allows for the easy recovery of organic polar solvents and is therefore cost-effective, but it lacks washing with an organic solvent, resulting in the problem of many impurities remaining. Patent Document 7 discloses a method in which, after the PAS production reaction is complete, PAS is recovered by flushing from a high-temperature, high-pressure state into a container at atmospheric pressure, and then washed and dried with water to obtain PAS, and then heat-treated at high temperature in the presence of an inert gas. However, high-boiling gas components cannot be removed, and high-boiling impurities remain, in addition to deterioration of the color. Patent Document 8 discloses a method for obtaining high-purity PAS by recovering PAS using a flash method, washing and drying it with water and acid, and then washing it with an organic solvent. However, the specific surface area of ​​the PAS obtained by the flash method is small, and the effect of reducing impurities by solvent washing is insufficient. Patent Document 9 discloses a method for improving the specific surface area of ​​PAS recovered by flash by contacting it with a specific organic solvent and removing specific compounds to achieve high purity. However, this method is complicated, and it is difficult to remove impurities that are poorly soluble in the organic solvent. 【0005】 Japanese Patent Publication No. 2010-126621, Japanese Patent Publication No. 2019-507825, Japanese Patent Publication No. 62-241961, Japanese Patent Publication No. 2014-28917, Japanese Patent Publication No. 62-232437, Japanese Patent Publication No. 61-255933, Japanese Patent Publication No. 2014-28917, Japanese Patent Publication No. 2023-152968, Japanese Patent Publication No. 2021-98815 【0006】 Prior technologies have struggled to address all the issues of high molecular weight, low halogen content, and high purity of PAS, and there has been a need for a PAS that possesses all of these properties, as well as an efficient method for producing PAS. 【0007】The inventors of the present invention have diligently studied to solve the above problems and have found that by performing a polymerization step in which a sulfidating agent and a predetermined amount of a dihalogenated aromatic compound are reacted in a polar solvent at 250°C or higher in the presence of a predetermined amount of polymerization stabilizer, and then removing the water generated by polymerization by venting before performing a precipitation and washing operation, it is possible to produce fine particulate PAS with reduced halogen content, chloroform extractable amount, and melt viscosity while maintaining a high molecular weight, leading to the present invention. That is, the present invention is as follows: 1. A polyarylene sulfide having a weight-average molecular weight of 20,000 or more and 90,000 or less, a chloroform extractable amount of 0.50% by weight or less, and a halogen end ratio of 20% or less to the total end. 2. The polyarylene sulfide according to item 1, having a weight-average molecular weight of 40,000 or more and 90,000 or less. 3. The polyarylene sulfide according to item 1 or 2, having a halogen end ratio of 15% or less to the total end. 4. 1. Polyarylene sulfide according to any one of claims 1 to 3, wherein the amount of cyclic polyarylene sulfide with 4 to 6 repeating units is 0.15% by weight or less. 5. Polyarylene sulfide according to any one of claims 1 to 3, wherein the amount of cyclic polyarylene sulfide with 4 to 6 repeating units is 0.10% by weight or less. 6. Polyarylene sulfide according to any one of claims 1 to 5, which is particulate polyarylene sulfide with a median diameter of 300 μm or less. 7. Polyarylene sulfide according to any one of claims 1 to 6, wherein the ratio of the amount of cyclic polyarylene sulfide with 7 to 8 repeating units to the amount of cyclic polyarylene sulfide with 4 to 14 repeating units is 45% by weight or more. 8. A resin composition to which a filler or additive has been added to the polyarylene sulfide according to any one of claims 1 to 7. 9. A molded article obtained by molding the resin composition according to claim 8. 10. A water-related component molded from the resin composition according to claim 8. 11. Powder coatings using the polyarylene sulfide described in any of items 1 to 7. 12. Fibers spun from the polyarylene sulfide described in any of items 1 to 7. 13. Films formed from the polyarylene sulfide described in any of items 1 to 7.14. A method for producing polyarylene sulfide, comprising a step 1 of polymerizing a sulfidating agent and a dihalogenated aromatic compound in an organic polar solvent in the presence of a polymerization stabilizer, the method comprising: step 1 of polymerizing the product at 250°C or higher; step 2 of dewatering the product after step 1; step 3 of washing the polymer obtained from the polymerization reaction with water or acid or both and then drying it; and step 4 of washing the dried polymer with an organic solvent. 15. The method for producing polyarylene sulfide according to item 14, wherein step 2 is carried out after the conversion rate of the dihalogenated aromatic compound in step 1 reaches 95% or higher. 16. The method for producing polyarylene sulfide according to item 14 or 15, wherein the amount of water in the reaction system in step 2 is 0.80 moles or less per 1.00 mole of sulfidating agent charged in step 1. 17. The method for producing polyarylene sulfide according to any one of items 14 to 16, wherein a step of distilling off the organic polar solvent and recovering solid matter is carried out between step 2 and step 3. 18. A method for producing polyarylene sulfide according to any one of items 14 to 17, wherein the ambient temperature when distilling off the organic polar solvent is 230°C or lower, and the temperature of the recovered solid is 230°C or lower. 19. A method for producing polyarylene sulfide according to any one of items 14 to 18, wherein the temperature of the solid is 230°C or lower from step 3 to step 4. 20. A resin composition obtained by adding a filler or additive to polyarylene sulfide obtained by the production method according to any one of items 14 to 19. 21. A molded article obtained by molding the resin composition according to item 20. 【0008】 The PAS according to the present invention is characterized by its high molecular weight, low chloroform extraction amount, and low halogen content. It exhibits excellent mechanical properties during molding and can suppress mold contamination. Furthermore, it provides a PAS with a low halogen content and low environmental impact. 【0009】 Embodiments of the present invention will be described in detail below. 【0010】 [Characteristics of PAS] The PAS of the present invention is characterized by having a weight-average molecular weight of 20,000 or more and 90,000 or less, a chloroform extract amount of 0.50% by weight or less, and a halogenated end ratio of 20% or less to the total end. 【0011】The lower limit of the weight-average molecular weight of PAS is 20,000, preferably 35,000 or more, more preferably 40,000 or more, and even more preferably 45,000 or more. The upper limit is 90,000, preferably 80,000 or less. A weight-average molecular weight of less than 20,000 is unsuitable because it reduces mechanical properties, and a molecular weight exceeding 90,000 is unsuitable because it greatly reduces melt fluidity and reduces processability. Details on how to adjust the weight-average molecular weight will be described later, but examples include adjustments made through polymerization steps such as polymerization time and amount of polymerization aids, and washing steps such as removal of low molecular weight components by washing with an organic solvent. The weight-average molecular weight refers to the value measured and calculated by dissolving PAS in a high-temperature organic solvent and performing high-temperature size exclusion chromatography (SEC). 【0012】 The upper limit of the chloroform extract is 0.50% by weight, preferably 0.40% by weight or less, and more preferably 0.35% by weight or less. There is no particular lower limit, but a smaller amount is preferable. If the chloroform extract exceeds 0.50% by weight, the melt viscosity during molding decreases, leading to a decrease in mechanical strength. Furthermore, it is unsuitable because it causes gas generation and mold contamination during molding, leading to molding defects. The chloroform extract is a low-molecular-weight impurity containing oligomers, and can be reduced by improving the washing efficiency of PAS and performing washing with an organic solvent. The chloroform extract amount referred to here is the weight percentage of the solid component obtained when chloroform is removed by Soxhlet extraction of PAS using chloroform, relative to the weight of PAS. In general, the chloroform extract component includes cyclic PAS, which will be described later, as well as low-molecular-weight compounds that act as impurities. 【0013】The upper limit for the proportion of halogen ends to the total ends of PAS is 20%, preferably 15% or less, and more preferably 10% or less. There is no particular lower limit, but it is generally 5% or more. The amount of halogen contained in polymers is strictly limited for reasons such as the generation of toxic gases during combustion, and the Japan Electronic Circuit Association (JPCA: PCA-ES01) stipulates that the halogen content in materials used in electrical and electronic components should be less than 900 ppm. If the proportion exceeds 20% to the PAS ends, it may not meet the regulations and is therefore unsuitable. The proportion of halogens at the ends of PAS generally exceeds 30%. In the polymerization of PAS, it is common to add an excess of dihalogenated aromatic compounds of monomers to the sulfur source, and the PAS ends often become halogens. Details of methods for reducing halogen ends will be described later, but it can be reduced by performing deliquidation before precipitation after polymerization of PAS. The proportion of halogens at the ends of PAS referred to here is the percentage of the total end value of PAS calculated from the number-average molecular weight of the halogen ends of PAS measured by combustion ion chromatography. 【0014】 The amount of cyclic PAS with 4 to 6 repeating units in the PAS is preferably 0.15% by weight or less, more preferably 0.10% by weight or less, and even more preferably 0.08% by weight or less. There is no particular lower limit, but a smaller amount is preferable. If the amount of cyclic PAS with 4 to 6 repeating units in the PAS exceeds 0.15% by weight, it may lead to an increase in deposits on the mold, an increase in the frequency of mold cleaning, and ultimately a decrease in productivity. This can be reduced by improving the cleaning efficiency of the PAS and performing cleaning with an organic solvent. The amount of cyclic PAS with 4 to 6 repeating units in the PAS refers to the weight percentage of the amount of cyclic PAS relative to the total PAS, obtained by liquid chromatography after completely dissolving the PAS in an organic solvent at high temperature, removing insoluble matter from the PAS solution, cooling the PAS solution, and then removing the precipitated PAS from the solution. 【0015】It is preferable that the proportion of cyclic PAS with 7 to 8 repeating units within the total amount of cyclic PAS with 4 to 14 repeating units is 45% by weight or more, and more preferably 48% by weight or more. There is no particular upper limit, but it is generally 55% by weight or less. If the proportion of cyclic PAS with 7 to 8 repeating units within the total amount of cyclic PAS with 4 to 14 repeating units is less than 45% by weight, the viscosity may decrease compared to PAS with the same molecular weight and the same amount of impurities (chloroform extract amount). This can be brought into a suitable range by drying the PAS recovered by washing with water and then washing it again with an organic solvent. 【0016】 [Structure of PAS] In the present invention, PAS is a homopolymer or copolymer whose main constituent unit is a repeating unit of formula -(Ar-S)-, preferably containing 80 mol% or more of said repeating unit. Ar can be represented by units shown in formulas (A) to (K) below, but formula (A) is particularly preferred. 【0017】 【0018】 (R1 and R2 are substituents selected from hydrogen, alkyl groups, alkoxy groups, and halogen groups, and R1 and R2 may be the same or different.) Generally, PAS may contain branched or crosslinked units represented by formulas (L) to (N) below, and branched / crosslinked units can be introduced by copolymerization with polyhalogenated aromatic compounds having three or more halogens, or by oxidative crosslinking by heating in the presence of oxygen. The introduction of branched / crosslinked units results in an increase in viscosity and an improvement in tensile strength. 【0019】 【0020】 Furthermore, the PAS in the present invention may be any of the following: a random copolymer containing the above repeating units, a block copolymer, or a mixture thereof. 【0021】Typical examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof, and mixtures thereof. Particularly preferred PAS is a polyphenylene sulfide resin containing 80 mol% or more, and especially 90 mol% or more, of the following p-phenylene sulfide units as the main constituent units of the polymer. 【0022】 【0023】 Furthermore, the cyclic PAS in this invention is a cyclic body whose main constituent unit is a repeating unit of the formula -(Ar-S)-. 【0024】 The method for manufacturing the PAS of the present invention will be described in detail below. 【0025】 First, let me explain the raw materials used in the manufacture of PAS. 【0026】 [Sulfidating Agent] The sulfidating agent used in the present invention can be any agent that can introduce a sulfide bond to a dihalogenated aromatic compound, such as alkali metal sulfides, alkali metal hydroxides, and hydrogen sulfide. 【0027】 Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these. Among these, lithium sulfide and / or sodium sulfide are preferred, and sodium sulfide is more preferred. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in anhydrous form. An 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 inexpensive alkali metal sulfides that are generally available are in the form of hydrates or aqueous mixtures, it is preferable to use alkali metal sulfides in this form. 【0028】Specific examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these. Among these, lithium hydrosulfide and / or sodium hydrosulfide are preferred, and sodium hydrosulfide is more preferred. 【0029】 Furthermore, alkali metal sulfides prepared in the reaction system from alkali metal hydroxides and alkali metal hydroxides can also be used. Alkali metal sulfides prepared in advance by contacting alkali metal hydroxides and alkali metal hydroxides can also be used. These alkali metal sulfides and alkali metal hydroxides can be used as hydrates or aqueous mixtures, or in anhydrous form, with hydrates or aqueous mixtures being preferred from the viewpoint of availability and cost. 【0030】 Furthermore, alkali metal sulfides prepared in the reaction system from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide can also be used. Alternatively, alkali metal sulfides prepared in advance by contacting alkali metal hydroxides such as lithium hydroxide and sodium hydroxide with hydrogen sulfide can be used. Hydrogen sulfide can be used in any form: gaseous, liquid, or aqueous solution. 【0031】[Dihalogenated Aromatic Compounds] Dihalogenated aromatic compounds are used when producing the PAS of the present invention. Examples of dihalogenated aromatic compounds that can be used include dihalogenated benzenes such as p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene, and dihalogenated aromatic compounds containing substituents other than halogens such as 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, 2,5-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2,5-dichloroaniline, and 3,5-dichloroaniline. Among these, dihalogenated aromatic compounds mainly composed of p-dihalogenated benzene, represented by p-dichlorobenzene, are preferred. From the viewpoint of preventing depolymerization of PAS during polymerization, the lower limit of the amount of dihalogenated aromatic compound is preferably 0.99 moles or more, and more preferably 1.00 mole or more, per 1.00 mole of sulfidating agent. From the viewpoint of obtaining high molecular weight PAS, the upper limit of the amount of dihalogenated aromatic compound is preferably 1.03 moles or less, and more preferably 1.02 moles or less, per 1.00 mole of sulfidating agent. The dihalogenated aromatic compound may be used alone or as a mixture of two or more different types. 【0032】[Branching and Crosslinking Agents] Specifically, branching and crosslinking agents for introducing branching and crosslinking units into the PAS include polyhalogenated aromatic compounds having three or more halogens, such as 1,3,5-trichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, and 1,4,6-trichloronaphthalene, and polyhalogenated aromatic compounds containing substituents other than halogens and having three or more halogens, such as 2,3,6-trichlorobenzoic acid, 2,4,5-trichlorobenzoic acid, 2,4,6-trichlorobenzoic acid, 2,3,4-trichloroaniline, and 2,4,6-trichloroaniline. Using these branching and crosslinking agents improves molecular weight, viscosity, and tensile strength, but causes increased molecular weight dispersion, decreased impact strength, extreme thickening, and a decrease in cooling crystallization temperature. There are no particular restrictions on these branching and crosslinking agents; they do not need to be used, and multiple agents can be used in combination. 【0033】 [Organic Polar Solvents] In the present invention, organic polar solvents are used as polymerization solvents. Organic amide solvents are preferred examples of organic polar solvents used. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphate triamide, as well as mixtures thereof, which are preferred due to their high reaction stability. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferred, and N-methyl-2-pyrrolidone is more preferred. 【0034】 The amount of organic polar solvent used is selected to be in the range of 2.00 moles to 10.00 moles, preferably 2.25 moles to 6.00 moles, and more preferably 2.50 moles to 5.50 moles per 1.00 mole of sulfidating agent. 【0035】[Polymerization Stabilizers] To stabilize the polymerization reaction system and prevent side reactions, it is important to allow the polymerization reaction of PAS to proceed in the presence of polymerization stabilizers. Polymerization stabilizers contribute to the stabilization of the polymerization reaction system and suppress undesirable side reactions. One indicator of a side reaction is the formation of thiophenol. The formation of thiophenol can be suppressed by adding polymerization stabilizers. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. Alkali metal carboxylates, which will be discussed later, also act as polymerization stabilizers and are therefore also included as polymerization stabilizers. Furthermore, as mentioned above, when using alkali metal hydroxides as sulfidating agents, it is particularly preferable to use alkali metal hydroxides at the same time, but in this case, alkali metal hydroxides in excess of the sulfidating agent can also act as polymerization stabilizers. 【0036】 These polymerization stabilizers can be used individually or in combination of two or more. The polymerization stabilizers are typically used in a ratio of 0.02 to 0.20 moles, preferably 0.03 to 0.10 moles, and more preferably 0.04 to 0.09 moles, per 1.00 mole of the sulfidizing agent. If the ratio is too low, the stabilization effect is insufficient, while conversely, if it is too high, it is economically disadvantageous and tends to reduce the polymer yield. 【0037】 There is no specific timing for adding the polymerization stabilizer; it can be added at any of the following stages: during the pre-processing stage, at the start of polymerization, or during the polymerization reaction stage. It can also be added in multiple stages. However, it is more preferable to add it simultaneously at the start of the pre-processing stage or at the start of polymerization, as this is easier. 【0038】[Polymerization Aid] To obtain high molecular weight PAS in a shorter time, it is preferable to use a polymerization aid. Here, the polymerization aid means a substance having an effect of increasing the viscosity of the obtained PAS. Specific examples of such a polymerization aid include, for example, organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. These can be used alone or two or more kinds can be used simultaneously. Among them, alkali metal carboxylates are preferable, and sodium acetate, which is inexpensive and has a high effect of increasing molecular weight, is preferable as the alkali metal carboxylate. 【0039】 The above alkali metal carboxylate is represented by the general formula R(COOM) ｎ (wherein, R is an alkyl group, cycloalkyl group, aryl group, alkylaryl group or arylalkyl group having 1 to 20 carbon atoms. M is an alkali metal selected from lithium, sodium, potassium, rubidium and cesium. n is an integer of 1 to 3). The alkali metal carboxylate can also be used as a hydrate, anhydride or aqueous solution. Specific examples of the alkali metal carboxylate include, for example, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluylate, and mixtures thereof. 【0040】 The alkali metal carboxylate may be synthesized by adding and reacting substantially equimolar amounts of an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates. Among the above alkali metal carboxylates, lithium salts have high solubility in the reaction system and a large auxiliary effect but are expensive. On the other hand, potassium, rubidium and cesium salts have insufficient solubility in the reaction system, so sodium acetate, which is inexpensive and has appropriate solubility in the polymerization system, is most preferably used. 【0041】The water used as the polymerization aid is preferably distilled water or ion-exchanged water in order not to impair the effect of the preferable chemical modification of PAS. 【0042】 In the present invention, it is preferable to use an alkali metal carboxylate as the polymerization aid, and more preferably to use sodium acetate. The alkali metal carboxylate is preferably present in an amount of 0.25 mol or more based on 1.00 mol of the sulfidizing agent. From the viewpoint of achieving a higher molecular weight, 0.30 mol or more is more preferable, 0.40 mol or more is further preferable, and 0.55 mol or more is still more preferable. Also, from the viewpoint of production, 0.50 mol or less is preferable, and 0.40 mol or less is more preferable. 【0043】 Also, when water is used as the polymerization aid, it is preferable that water is present in an amount of 0.50 mol or more based on 1.00 mol of the sulfidizing agent in the reaction vessel. In terms of obtaining a higher molecular weight, 0.60 mol or more is more preferable, and 0.70 mol or more is further preferable. As the upper limit when water is used as the polymerization aid, from the viewpoint of safety regarding the pressure in the reaction vessel, it is preferable that water is present in an amount of 1.50 mol or less based on 1.00 mol of the sulfidizing agent, more preferably 1.25 mol or less, and still more preferably 1.00 mol or less. Although the present invention is characterized by liquid separation in Step 2, even when water is added as the polymerization aid, it is preferable that the amount of water in the reaction system after liquid separation is 0.80 mol or less based on 1.00 mol of the charged sulfidizing agent amount in Step 1. 【0044】 These polymerization aids can also be used in combination of two or more. For example, when an alkali metal carboxylate and water are used in combination, even with a smaller amount of the alkali metal carboxylate, it is possible to achieve a higher molecular weight. 【0045】There are no specific timing requirements for adding these polymerization aids; they may be added during the pre-processing stage, at the start of polymerization, or during the polymerization reaction stage, as described later. They may also be added in multiple stages. However, it is preferable to add them simultaneously with other additives at the start of the pre-processing stage or at the start of polymerization, as this makes the addition process easier. When using water as a polymerization aid, it is effective to add it after adding the dihalogenated aromatic compound, and then add it during the polymerization reaction stage. 【0046】 Next, I will explain each step in order. 【0047】 [Pre-process to Polymerization Process] (Process 1) First, the pre-process will be explained. When producing the PAS of the present invention, the sulfidating agent is used in hydrate form, but it is preferable to heat the mixture containing the organic polar solvent and the sulfidating agent before adding the dihalogenated aromatic compound to remove excess water from the system. 【0048】 Furthermore, as mentioned above, sulfidating agents prepared from alkali metal hydroxides and alkali metal hydroxides in situ within the reaction system or in a separate tank from the polymerization tank can also be used as sulfidating agents. There are no particular limitations to this method, but preferably, under an inert gas atmosphere, alkali metal hydroxides and alkali metal hydroxides are added to an organic polar solvent at a temperature range of room temperature to 150°C, preferably room temperature to 100°C, and the temperature is raised to at least 150°C, preferably 180°C to 260°C, under atmospheric pressure or reduced pressure, to remove water by distillation. Polymerization aids may be added at this stage. The order in which these raw materials are charged does not matter, and they can be added simultaneously. In addition, toluene or the like may be added to accelerate the removal of water. Polymerization stabilizers are preferably added in this step or in the polymerization step. The polymerization stabilizer is preferably 0.02 to 0.20 moles per 1.00 mole of sulfidating agent charged. When alkali metal hydroxides and alkali metal hydroxides are used as sulfidating agents, it is preferable that the amount of alkali metal hydroxide is 1.02 to 1.20 moles per 1.00 mole of alkali metal hydroxide. 【0049】The amount of water in the system at the end of the preceding step, i.e., before the polymerization reaction step, is preferably 0.01 moles to 1.00 moles per 1.00 mole of sulfidizing agent added. Here, the amount of water in the system is the amount of water added to the polymerization system minus the amount of water removed from the polymerization system. The water added may be in any form, such as water, aqueous solution, or crystal water. 【0050】 Furthermore, when water is removed in the preceding step, hydrogen sulfide derived from the sulfidating agent may be generated and distilled off along with the water. In this invention, the amount of sulfidating agent used in the preparation refers to the amount obtained by subtracting the amount of hydrogen sulfide distilled off as a result of water removal. 【0051】 Next, the polymerization process will be described. When producing the PAS of the present invention, it is preferable to carry out a polymerization process in which the reactant prepared in the previous step and the dihalogenated aromatic compound are brought into contact in an organic polar solvent to carry out a polymerization reaction. 【0052】 In the polymerization process, it is preferable to have at least 0.20 moles of polymerization aid per 1.00 mole of sulfidating agent, and at least 0.99 moles to 1.03 moles of dihalogenated aromatic compound per 1.00 mole of sulfidating agent. 【0053】 Here, it is preferable to include a polymerization aid in an amount of 0.20 moles or more, as this increases the molecular weight of the resulting PAS. More preferably, it is 0.30 moles or more. There is no upper limit, but it is generally preferable to include it in an amount of 1.00 mole or less. By using it within the above preferred range, the molecular weight of PAS is efficiently increased. Also, as mentioned above, the polymerization aid may be added in a previous step. 【0054】 To initiate the polymerization process, the organic polar solvent, sulfidating agent, and dihalogenated aromatic compound are mixed, preferably under an inert gas atmosphere, at a temperature range of 25°C to 260°C, more preferably 100°C to 250°C. A polymerization aid may be added at this stage. The order in which these raw materials are added does not matter, and they can be added simultaneously. 【0055】This mixture is typically heated to a temperature of 200°C to 280°C. There are no particular restrictions on the heating rate, but a rate of 0.01°C / min to 5°C / min is usually selected, with a range of 0.1°C / min to 3°C / min being more preferable. Within the aforementioned range of heating rates, the rate does not necessarily have to be constant; there may be constant temperature intervals, and heating can be performed in multiple stages without issue. There may also be intervals where the heating rate is temporarily negative, as long as the essence of the present invention is not impaired. 【0056】 Ultimately, the reaction needs to be carried out at a temperature of 250°C or higher, and generally the upper limit of the reaction temperature is 280°C or lower. The reaction is carried out at that temperature for typically 0.25 hours to 50 hours, preferably 0.50 hours to 20 hours. 【0057】 A method in which the reaction is carried out at a certain temperature, for example, 200°C to 250°C for a certain period of time before reaching the final temperature, and then the temperature is raised to 250°C to 280°C or below, is effective in obtaining a higher molecular weight. In this case, the reaction time at 200°C to 250°C is usually selected to be in the range of 0.25 hours to 20 hours, preferably in the range of 0.25 hours to 10 hours. Furthermore, it is desirable that the conversion rate of the dihalogenated aromatic compound in the system at the point when the temperature is raised to 250°C to 280°C or below after the reaction at 200°C to 250°C for a certain period of time is 60% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The conversion rate of the dihalogenated aromatic compound (abbreviated as HA here) is the value calculated by the following formula. The amount of remaining HA can usually be determined by gas chromatography. (A) When a dihalogenated aromatic compound is added in excess in molar ratio relative to an alkali metal sulfide, the conversion rate = [Amount of HA added (moles) - Amount of HA remaining (moles)] / [Amount of HA added (moles) - Excess HA (moles)] (B) In cases other than (A) above, the conversion rate = [Amount of HA added (moles) - Amount of HA remaining (moles)] / [Amount of HA added (moles)]. 【0058】In the present invention, the polymerization time in the polymerization step is preferably 60 minutes or more, and more preferably 120 minutes or more, from the viewpoint of increasing the molecular weight of PAS. On the other hand, the upper limit of the polymerization time is preferably 360 minutes or less, more preferably 240 minutes or less, and even more preferably 190 minutes or less, from the viewpoint of productivity. The polymerization time referred to here includes the heating and cooling time within a temperature range of 200°C to 280°C from the time the sulfidating agent and the dihalogenated aromatic compound are charged until the start of the deliquidation step from the reaction vessel. 【0059】 In the polymerization process, it is preferable that there be 0.50 moles or more of water per 1.00 mole of sulfidating agent added. To obtain a higher molecular weight, 0.60 moles or more is more preferable, and 0.70 moles or more is even more preferable. As an upper limit when water is used as a polymerization aid, from the viewpoint of safety regarding the pressure in the reaction vessel and the handling of the resulting polymer particle size, it is preferable that there be 1.50 moles or less of water per 1.00 mole of sulfidating agent added, and more preferably 1.25 moles or less. Note that the water content in the polymerization process represents the amount of water within the temperature range of 250°C to 280°C during the polymerization process, and is the amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water added to the polymerization system and the amount of water generated by the polymerization reaction. 【0060】[Deliquidation Process] (Step 2) In order to produce the PAS of the present invention, it is important to remove water by deliquidation after polymerization. By removing water while the PAS has not precipitated during deliquidation, the particle size and specific surface area of ​​the PAS can be kept within a preferred range. Generally, polymerized PAS begins to precipitate at 210 to 230°C, so when performing deliquidation, a temperature of 240°C or higher is preferable, 250°C or higher is more preferable, and 270°C or higher is even more preferable. The specific surface area referred to here refers to the surface area per unit weight, and is measured using nitrogen gas by gas adsorption and the value of the specific surface area calculated by the BET multipoint method. In the polymerization reaction of PAS, theoretically, 1.00 mole of water is produced for every 1.00 mole of sulfidizing agent added, but it is preferable to reduce the amount of water in the reaction vessel by the deliquidation operation to 0.80 moles or less, and more preferably 0.70 moles or less, relative to the 1.00 mole of sulfidizing agent added in Step 1. There is no particular lower limit on the amount of water. By reducing the amount of water in the reaction vessel to 0.80 moles or less relative to the amount of sulfidating agent used (1.00 mole), phase separation within the system is eliminated, reducing the particle size to 200 μm or less and increasing the surface area per unit weight. This significantly reduces the amount of halogen, chloroform extracted, and cyclic compounds when washing with the organic solvent described later. The surface area referred to here is the area of ​​the part that does not include the area inside the pores calculated from the particle size. Deliquorization is preferably carried out when the conversion rate of the dihalogenated aromatic compound is 95% or higher, more preferably 98% or higher, and even more preferably 99% or higher, from the viewpoint of suppressing the high degree of polymerization and decomposition reaction of PAS. Deliquorization is undesirable when the conversion rate is low, as the monomer dihalogenated aromatic compound may be removed from the system, causing decomposition of PAS. 【0061】There are no particular restrictions on the method of deliquidation, but one example is to open the top of the reaction vessel at a high temperature and cool and recover the vapor. At this time, since the amount of water in the reaction vessel affects the shape of the PAS, it is necessary to remove water by deliquidation while the PAS is molten, and the temperature of the reaction solution is preferably 230°C or higher, preferably 240°C or higher, and more preferably 250°C or higher. If the temperature is below 230°C, the PAS may start to precipitate, which is undesirable. The upper limit temperature for deliquidation is 300°C, and preferably 280°C or lower. If it exceeds 300°C, it may promote the decomposition reaction and is therefore unsuitable. It is possible to perform deliquidation while maintaining the temperature after polymerization, or the temperature may be changed during deliquidation. From the viewpoint of thermal efficiency, it is preferable to perform deliquidation while maintaining the temperature after polymerization. The time spent on deliquidation is usually selected from 0.10 hours to 10 hours, preferably from 0.10 hours to 2.0 hours, and more preferably from 0.10 hours to 1.0 hour. If the deliquidation time is too long, it may cause decomposition and is also undesirable from the viewpoint of productivity. Furthermore, during the dewatering process, organic solvents other than water used in polymerization, as well as the monomers, which are dihalogenated aromatic compounds, may distill off together. By removing unreacted dihalogenated aromatic compounds before precipitation, it is possible to reduce the proportion of chlorine-terminated PAS in the subsequent organic solvent washing step. 【0062】 [Recovery Process] In the method for producing polyarylene sulfide of the present invention, after polymerization is complete, solid material is recovered from the polymerization reaction product containing the polymer and solvent. Typical recovery methods include a method of cooling and filtering the precipitated PAS, and a method of distilling off the organic polar solvent, with the method of distilling off the organic polar solvent being preferred. 【0063】 There are no particular restrictions on the method for recovering the solid by distilling off the organic polar solvent from the reaction mixture. Examples include heating the resulting reaction mixture above the boiling point of the organic polar solvent to remove the solvent by distillation, or the flash method. The flash method involves heating the polymerization reaction mixture to high temperature and pressure (usually 250°C or higher, 8 kg / cm³). ２This method involves flashing the mixture from the above state into an atmosphere of normal or reduced pressure to recover the solvent and the polymer in powder form simultaneously. Flashing here means ejecting the polymerization reaction product from a nozzle. The atmosphere used for flashing can be, for example, nitrogen or water vapor at normal pressure, and its temperature is usually selected in the range of 150°C to 250°C. From the viewpoint of increasing purity, the atmosphere temperature is preferably 230°C or lower, and more preferably 220°C or lower. By keeping the atmosphere temperature below 230°C, pore blockage of the PAS surface can be prevented, resulting in a PAS with a high specific surface area, improving washing efficiency, and making it easier to remove chloroform extract and cyclic material in subsequent processes. For the same reason, it is also preferable to keep the temperature of the solid recovered by the flashing method below 230°C, as exceeding 230°C tends to reduce the specific surface area. The flashing method is an economically efficient recovery method because it allows for simultaneous recovery of the solvent and solid, and the recovery time is relatively short. In this invention, deliquidation must be performed before the start of flashing to reduce the moisture content to a specified value or lower. Furthermore, the method of rapidly cooling and filtration-recovering the precipitated PAS is preferable to the flash method, as it can obtain fine powdered PAS, and its high surface area and specific surface area allow for the acquisition of high-purity PAS. Another method for recovering polyarylene sulfide is the quench method, in which the polymerization reaction product is gradually cooled while crystallizing, and then the solid is recovered by filtration. However, this method takes longer to recover than the flash method because of the gradual cooling, and due to the nature of filtration, fine polymer components cannot be recovered, which tends to worsen yield and productivity. In addition, a separate step is required to separate the sieved material from an organic polar solvent such as NMP. In the quench method, unreacted dihalogenated aromatic compounds react with the PAS ends during slow cooling, increasing the amount of chlorine ends, and the particle size grows larger, leading to a decrease in surface area and making it easier for low-molecular-weight impurities to be trapped. 【0064】 [Water or acid washing] (Step 3) In the present invention, it is preferable to wash the PAS with water and then with acid after the recovery step. 【0065】Since the solid material obtained in the recovery process contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidating agents, it is preferable to wash it with water. When washing the PAS, it is preferable to set the water temperature to 40°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher. Washing at 70°C or higher is particularly preferable because it provides a desirable chemical modification effect on the PAS. In order to exhibit the desirable chemical modification effect on the PAS by water washing, it is preferable to use distilled water or ion-exchanged water. There are no particular restrictions on the water washing operation. Examples include adding a predetermined amount of PAS to a predetermined amount of water and heating and stirring in a pressure vessel, or continuously washing with water. It is preferable that there is more water than PAS in the ratio of PAS to water, and usually a bath ratio (weight of washing solution to weight of dry PAS) of 200 g or less of PAS per 1 kg of water is selected. 【0066】 Next, it is preferable to wash the PAS with an acid. Examples of acid washing are as follows. The acid used to wash the PAS is not particularly limited as long as it does not have the effect of decomposing the PAS, and examples include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonate, and propyl acid. Among these, acetic acid and hydrochloric acid are more preferably used. On the other hand, substances that decompose or degrade the PAS, such as nitric acid, are undesirable. 【0067】 Furthermore, to avoid undesirable decomposition of reactive functional groups, it is desirable to perform the washing under an inert atmosphere. In addition, to remove any remaining components, it is preferable to wash the PAS with water several times after the acid washing operation. 【0068】One method of cleaning with acid is to immerse the PAS in acid or an aqueous solution of acid, and heating is preferable. Stirring is also possible if necessary. The amount of acid is preferably 5.0 mol% or more, more preferably 7.0 mol% or more, with a preference of 20.0 mol% or less, more preferably 15.0 mol% or less, and even more preferably 10.0 mol% or less, relative to the amount of PAS when dry. In this case, the amount of acid is the value obtained by multiplying the amount of acid used by the valence of the acid, and the amount of PAS is the value obtained by dividing the dry weight of PAS by the unit molecular weight of PAS. If the acid concentration is too low, the cleaning effect will decrease, the ash content will increase and the crystallinity will decrease, which is undesirable, while if it is too high, it is undesirable from the standpoint of corrosion to equipment and economic considerations. The temperature for acid cleaning is preferably 150°C or higher, more preferably 170°C or higher, and even more preferably 190°C or higher. The maximum temperature is preferably 220°C or lower, more preferably 210°C or lower, and even more preferably 200°C or lower. Low temperatures are undesirable because they reduce the cleaning effect, increase the ash content, and decrease crystallinity, while excessively high temperatures are undesirable because they increase the risk from a safety standpoint regarding the pressure in the reaction vessel. There are no particular restrictions on the bath ratio during acid washing, and it can generally be arbitrarily selected between 1 and 50. In this case, the bath ratio refers to the total amount (g) of washing solution relative to the weight (g) of dry PAS. There are no particular limitations on the method of acid washing at high temperatures, but generally, washing is performed at high temperature and high pressure using a pressure vessel or the like. For example, when using acetic acid, sufficient effect can be obtained by immersing the PAS powder in an aqueous solution of 5.0 mol% acetic acid added to PAS heated to 170°C to 200°C in a pressure reaction vessel and stirring for 30 minutes. To remove residual acid or salts from the PAS that has been washed with acid, it is preferable to wash it several times with water. The water used for washing is preferably distilled water or deionized water so as not to impair the desirable chemical modification effect of PAS by acid washing, and higher temperatures are preferable as they increase the washing efficiency. 【0069】Furthermore, drying is necessary in the subsequent step 4 to improve the efficiency of removing halogen and chloroform extracts. There are no restrictions on the drying method, but drying under an inert atmosphere or vacuum is preferable to suppress undesirable crosslinking reactions of PAS. Also, the maximum temperature during drying is preferably 230°C or lower, and more preferably 200°C or lower, from the viewpoint of maintaining a high specific surface area. If drying is performed above 230°C, the surface pores tend to become blocked, reducing the specific surface area, which tends to worsen the washing efficiency in the subsequent step 4 and result in insufficient removal of chloroform extracts, etc. From the viewpoint of maintaining the acid value of PAS, 170°C or lower is preferable, and more preferably 150°C or lower. 【0070】[Washing with organic solvent] (Step 4) In the present invention, it is important to wash the PAS with an organic solvent in order to keep the amount of chloroform extract components and halogens contained in the obtained PAS within a desirable range. Acid washing is more preferable because it increases the efficiency of removing halogen and oligomer components. When washing with an organic solvent, the procedure is as follows. The organic solvent used to wash the PAS is not particularly limited as long as it does not have the effect of decomposing the PAS. For example, examples of organic solvents used for cleaning PAS include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphorusamide, and piperadinons; sulfoxide and sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; ether solvents such as dimethyl ether, dipropyl ether, dioxane, and tetrahydrofuran; halogen solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene; alcohol and phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol; and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, the use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform is particularly preferred. Furthermore, these organic solvents may be used individually or in combination of two or more. 【0071】The smaller the particle size and the larger the specific surface area of ​​the dried PAS subjected to washing with an organic solvent, the more efficiently impurities can be removed. Preferably, the particle size is 300 μm or less, and more preferably 200 μm or less, after the completion of the preceding step 3. The particle size can be kept within a preferred range by performing step 2, which is characteristic of the present invention. In particular, PAS with a large weight-average molecular weight tends to have a larger particle size, and step 2 makes it possible to keep the particle size within a preferred range. If step 2 is not performed, both the median diameter and the polydispersity index (PDI) will be large. Step 4 does not affect the particle size. The particle size referred to here is the median diameter, which is the value of the particle size at which the cumulative frequency is 50% from the particle size distribution measured wet by laser diffraction and scattering. 【0072】 Furthermore, the specific surface area is 8 m². ２ It is preferable that it exceeds / g, and 10m ２ It is more preferable that the amount is 1 / g or more. The specific surface area is affected by heating after precipitation, and when heated above 230°C, it becomes 8m ２ The washing efficiency deteriorates when the amount falls below / g. Since the specific surface area is greatly affected by the temperature history after precipitation, it is preferable to keep the maximum temperature of the solids below 230°C throughout steps 3 and 4. In the flash method, the specific surface area can be kept within a desirable range by keeping the ambient temperature and the solid temperature below 230°C. 【0073】One method of cleaning with an organic solvent is to immerse the PAS in the organic solvent, and heating is preferable. Stirring can also be performed as needed. There are no particular restrictions on the cleaning temperature when cleaning the PAS with an organic solvent, but cleaning at a temperature of 70°C or higher is preferable, 80°C or higher is more preferable, and 90°C or higher is even preferable. There are no particular upper limits, and cleaning efficiency tends to increase with higher cleaning temperatures, but the maximum is 300°C, and sufficient effect can be obtained at around 150°C. It is also possible to clean under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There are also no particular restrictions on the cleaning time. Depending on the cleaning conditions, in the case of batch cleaning, sufficient effect can usually be obtained by cleaning for 15 minutes or more. Furthermore, it is preferable that the cleaning time be no longer than 24 hours, more preferably within 12 hours, and even more preferably within 7 hours. If the temperature is too low or the time is too short, sufficient cleaning effect cannot be obtained. Even if cleaning is done for a long time, the cleaning effect does not change, and the longer the time, the less economically viable it becomes. Continuous cleaning is also possible. In the post-treatment process, it is preferable to use a combination of water washing, acid washing, drying, and washing with an organic solvent, from the viewpoint of the amount of chloroform extracted and the amount of halogen. 【0074】 When washing with an organic solvent, it is preferable that the concentration of the washing organic solvent after washing for a predetermined time be 80% or higher. In washing with an organic solvent, mainly soluble components such as low molecular weight substances and impurities in the PAS are eluted. However, if a large amount of soluble components or water from the previous process remains, the concentration of the washing organic solvent decreases and a sufficient cleaning effect cannot be obtained. The washing organic solvent referred to here refers to the liquid component when it coexists with the PAS in the washing tank, and basically includes the organic solvent added as the washing solution, as well as low molecular weight components, impurities, and water remaining in the PAS. The concentration of the washing organic solvent referred to here can be expressed as [(amount of organic solvent added) + (amount of organic solvent contained in the PAS)] / [(amount of organic solvent added) + (amount of organic solvent remaining in the PAS) + (low molecular weight components, impurities, water, and other soluble components in the washing solution in the PAS)] × 100 (%). 【0075】When using a mixed organic solvent as a cleaning solution, the entire mixed organic solvent is considered as (amount of organic solvent added) in the above formula. When using a water-soluble organic solvent as a cleaning solution, if a large amount of water remains in the PAS, the concentration of the cleaning organic solvent will be greatly reduced during cleaning. Therefore, it is preferable to reduce the amount of water before cleaning with the organic solvent. Methods for reducing the amount of water include substitution with a water-soluble organic solvent or including a drying step. When cleaning with a non-water-soluble organic solvent, the organic solvent and water do not mix, and the concentration of the cleaning organic solvent does not substantially decrease in the concentration measurement using a gas chromatograph described later. Therefore, a step to reduce the amount of water is not necessarily required. Also, from the viewpoint of maintaining the concentration of the cleaning organic solvent, the bath ratio of the organic solvent added to the weight of the dry PAS is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. There is no limit to the preferred range for the upper limit, but due to economic considerations and constraints due to the size of the equipment, it is generally carried out with a bath ratio of 10 or less. The concentration of the organic solvent used for washing can be measured using a calibration curve with a gas chromatograph in accordance with JIS K 0114 (2012). For the analysis method, the washing solution may be sampled and analyzed after washing for a predetermined time, or the filtrate after washing may be analyzed. 【0076】 In this invention, it is preferable that the post-treatment steps be carried out in the following order: washing the solid containing polyarylene sulfide with water, acid, or both; reducing the moisture content by drying or the like; and washing with an organic solvent. In particular, washing with acid can protonate impurities, thereby improving the washing efficiency in step 4. This allows for the efficient removal of chloroform extract components and halogens. 【0077】 The yield of PAS obtained after the completion of all processes can be considered based on the amount of sulfur in the system. A higher yield is preferable, but from a productivity standpoint, it is preferable to have a yield of 90% or more. 【0078】[Applications of PAS] The high molecular weight, high purity, and low halogen content PAS of the present invention has excellent heat resistance, chemical resistance, flame retardancy, electrical properties, and mechanical properties, and can be used not only for injection molding, injection compression molding, and blow molding, but also for extrusion molding to form extruded products such as sheets, films, fibers, and pipes. 【0079】 Generally, PAS is sometimes subjected to heat treatment for the purpose of improving its strength or removing volatile components, and heat treatment may be performed to the extent that it does not impair the effects of the present invention. 【0080】 Because the PAS of the present invention has excellent fluidity and moldability, its applications include electrical and electronic components, precision machinery components, plumbing components, office equipment, automobile and vehicle components, building materials, packaging materials, furniture, daily necessities, and coatings and linings, and it is particularly useful for electrical and electronic components, plumbing components, automobile and vehicle components, and coatings and linings. 【0081】 The PAS of this invention is particularly useful as a component for water-related applications due to its excellent chemical resistance, heat and humidity resistance, and water resistance. For example, it exhibits high durability and corrosion resistance over the long term in components that come into direct contact with water, such as water supply pipes, drainage pipes, valves, pump parts, faucet parts, piping and fittings around bathrooms and kitchens, and water purifier parts. Furthermore, its low halogen content results in a low environmental impact, minimal mold contamination during molding, and excellent appearance quality, making it highly reliable from a hygienic standpoint. 【0082】The PAS obtained by the present invention can also be used with fillers or additives, provided that the effects of the present invention are not impaired. Specific examples of such fillers include organic fillers and inorganic fillers, and fibrous fillers and non-fibrous fillers may be used. The shape of the fibrous filler is not particularly limited, and can be appropriately selected as needed from among fiber bundles such as chopped strands and rovings, woven fabrics such as plain weave and twill weave, knitted fabrics, nonwoven fabrics, fiber paper, and UD materials (unidirectional materials). The type of fibrous filler is not particularly limited, and examples include carbon fibers, metal fibers, organic fibers, and inorganic fibers. Two or more of these may be used. Specific examples of such additives can be appropriately selected as needed from among coupling agents, release agents, antioxidants, and elastomers. One or more of these may be used. It is also possible to contain both fillers and additives. 【0083】 The PAS of the present invention has a small particle size in the resulting raw powder, and its dispersion diameter and polydispersity index (PDI) can be reduced by classification or simple grinding. The particulate PAS obtained in this way has excellent mechanical properties, chemical resistance, and heat resistance, and can be suitably used as a powder coating for coating metal parts and home appliance parts. It is also suitable as a raw material for powder bed fusion 3D printers, exhibiting high dimensional stability and durability even in the manufacture of precision molded products. Due to its low halogen content, the generation of harmful gases during firing is suppressed, making it superior in terms of the working environment and product safety. 【0084】 As a method for manufacturing a PAS film using the PAS of the present invention, known melt-forming methods can be employed. For example, a method in which PAS is melted in a single-screw or twin-screw extruder, then extruded from a film die and cooled on a cooling drum to produce a film, or a biaxial stretching method in which the film thus produced is stretched longitudinally and transversely using a roller-type longitudinal stretching device and a transverse stretching device called a tenter, but the invention is not limited to these methods. 【0085】The PAS film obtained in this way possesses excellent mechanical, electrical, and heat-resistant properties, making it suitable for various applications such as dielectric films for film capacitors and chip capacitors, release films, insulating films for electronic components, packaging materials, and industrial barrier films. In particular, its low chlorine content results in a low environmental impact, and its high purity leads to less gas generation and contamination during molding, resulting in high appearance quality and reliability. 【0086】 As a method for producing PAS fibers using the PAS of the present invention, known melt spinning methods can be applied. For example, a method can be employed in which PAS chips, which are the raw material, are kneaded while being supplied to a single-screw or twin-screw extruder, and then extruded from a spinneret through a polymer streamline changer, a filtration layer, etc., installed at the tip of the extruder, followed by cooling, stretching, and heat setting. However, the invention is not limited to this method. 【0087】 The PAS monofilaments, multifilaments, and short fibers obtained in this way are suitable for various applications such as paper dryer canvas, net conveyors, bag filters, industrial filters, heat-resistant fibers, chemical-resistant fibers, and reinforcing materials. Due to their low chlorine content, they are environmentally friendly and suppress the generation of harmful gases during incineration. Furthermore, their excellent heat resistance, chemical resistance, and mechanical strength ensure stable performance over long periods even in harsh environments. 【0088】 The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. 【0089】 [Weight-average molecular weight] The weight-average molecular weight Mw was calculated in polystyrene equivalent using gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). The GPC measurement conditions are as follows: Apparatus: Senshu Scientific SSC-7110 Column name: Agilent PLgel MIXED-B x 2, PLgel 10 μm Guard Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C Pre-temperature bath temperature: 250°C Pump temperature bath temperature: 50°C Detector temperature: 210°C Flow rate: 1.0 mL / min Sample injection volume: 300 μL. 【0090】 [Number of end molecules per gram] Similar to the weight-average molecular weight described above, the number-average molecular weight Mn was calculated, and using this value, the number of end molecules per gram was calculated as follows: 1g / (number-average molecular weight Mn) × 2 = (number of end molecules per gram). 【0091】 [Halogen End Ratio to Total Ends] The amount of chlorine in PAS was measured by combustion ion chromatography. Using a Dia Instruments AQF-100 automated sample combustion system, 10 mg of polymer was combusted at a final temperature of 1000°C. The generated gas components were absorbed into 10 mL of water containing a dilute oxidizing agent, and the absorption solution was subjected to an ion chromatography system with a sodium carbonate / sodium bicarbonate mixed aqueous solution as the mobile phase to measure the amount of halogen in the polymer. The halogen atoms detected and quantified in this polymer refer to fluorine, chlorine, bromine, and iodine. The sum of the weights of each halogen contained in 1 g divided by their atomic weights was defined as (total amount of halogens contained in 1 g), and the halogen end ratio to total ends was calculated using the following formula: (Total amount of halogens contained in 1 g) / (Number of ends per 1 g) × 100 = (Halogen end ratio to total ends). 【0092】 [Chloroform Extraction Amount] The amount of chloroform extractable components in PAS was determined by weighing out 10 g of polymer and performing Soxhlet extraction with 150 g of chloroform for 3 hours. After removing the chloroform from the extract, the weight of the obtained components was measured, and the weight percentage relative to the weight of the charged polymer was calculated. 【0093】 [Amount of cyclic PAS in PAS] The amount of cyclic compounds in PAS was calculated using high-performance liquid chromatography (HPLC) as follows. 【0094】Approximately 10 mg of PAS was dissolved in approximately 5 g of 1-chloronaphthalene at 250°C. A precipitate formed upon cooling to room temperature. The 1-chloronaphthalene-insoluble components were filtered using a 0.45 μm pore size membrane filter to obtain the 1-chloronaphthalene-soluble components. The amount of cyclic compounds with 4 to 14 repeating units was quantified by HPLC measurement of the obtained soluble components, and the amount of cyclic PAS with 4 to 6 repeating units, the amount of cyclic PAS with 7 to 8 repeating units, and the ratio of the amount of cyclic PAS with 7 to 8 repeating units to the amount of cyclic PAS with 4 to 14 repeating units were calculated. The HPLC measurement conditions are as follows: Apparatus: Shimadzu Corporation LC-10Avp series Column: Mightysil RP-18 GP150-4.6 (5 μm) Detector: Photodiode array detector (UV = 270 nm). 【0095】 [Weight loss upon heating] 5g of PAS was placed in an aluminum cup, heated at 150°C for 1 hour, dried, and its weight was recorded. The amount of weight loss after heating at 327°C for 1 hour was measured, and the percentage of weight loss relative to the dried PAS was calculated. 【0096】 [Specific Surface Area] The amount of nitrogen adsorbed at liquid nitrogen temperature at each relative pressure was measured. The specific surface area was determined by the BET multipoint method (relative pressure 0.1 to 0.3). The measurements were performed after degassing the sample under reduced pressure at room temperature for at least 5 hours. 【0097】 Equipment: Autosorb-iQ manufactured by Anton Paar; Adsorbate: Nitrogen; Measurement temperature: 77K (liquid nitrogen temperature); Analysis method: BET multipoint method. 【0098】 [Particle Size (Median Diameter)] A dispersion was prepared by adding approximately 100 mg of polyarylene sulfide particles to approximately 5 mL of deionized water, and then adding Triton X-100 dropwise until dispersion was possible. The dispersion was added to a Nikkiso Co., Ltd. laser diffraction particle size distribution analyzer (Microtrac MT3300EX II) until it reached a measurable concentration. Ultrasonic dispersion was performed in the analyzer at 30 W for 60 seconds, and then the particle size distribution was measured for 10 seconds. The particle size at which the cumulative frequency reached 50% was calculated as the median diameter from the particle size distribution. 【0099】[Melting Viscosity (MFR)] In this invention, melting viscosity was evaluated using MFR. A higher MFR indicates lower melting viscosity, and a lower MFR indicates higher melting viscosity. The measurement method was as follows: Measurement was performed according to ASTM D 1238-70 at a temperature of 315.5°C and a load of 5,000 g. A melt indexer manufactured by Toyo Seiki Co., Ltd. (orifice with length 8.00 mm and hole diameter 2.095 mm) was used, with a sample amount of 7 g and a preheating time of 5 minutes from sample preparation to the start of measurement. 【0100】 [Example 1] In an autoclave equipped with a stirrer and a bottom valve, 118.03 g (1.00 mol) of 47.5% sodium hydroxide, 41.04 g (1.00 mol) of 96% sodium hydroxide, 208.17 g (2.10 mol) of N-methyl-2-pyrrolidone (NMP), 27.07 g (0.33 mol) of sodium acetate, and 78.57 g of deionized water were charged. The mixture was gradually heated to 225°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling was started when 140.57 g of water and 4.00 g of NMP were distilled off. At this point, the amount of hydrogen sulfide distilled off was 0.02 mol, so the amount of sulfidating agent in the system after this process was 0.98 mol. 【0101】 Step 1: The mixture was then cooled to 160°C, and 147.24 g (1.00 mol) of p-dichlorobenzene (p-DCB) and 79.30 g (0.80 mol) of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised from 200°C to 240°C at a rate of 0.6°C / min while stirring. After that, the temperature was raised from 240°C to 276°C at a rate of 0.8°C / min and the reaction was carried out for 130 minutes. 【0102】 Step 2 Next, the autoclave temperature was lowered at a rate of 0.5°C / min. When it reached 250°C, the valve connected to the top lid was opened, and the steam was cooled and collected in a separate tank. The composition of the collected liquid was 12.0 g of water, 0.6 g of NMP, and 1.4 g of p-DCB. The amount of water in the system was 0.32 moles per 1.00 mole of sulfidizing agent used in Step 1. 【0103】After dewatering, the bottom valve was opened, and the contents were flushed into a container with a stirrer over 15 minutes while pressurizing with nitrogen. The container with the stirrer was heated in a 280°C steam atmosphere with the heater temperature set to 250°C, and stirred until the internal temperature reached 230°C to remove most of the NMP. 【0104】 Step 3 The recovered material and ion-exchanged water with a bath ratio of 10 were placed in an autoclave with a stirrer, washed at 70°C for 30 minutes, and then filtered by suction using a glass filter. Next, ion-exchanged water with a bath ratio of 10 heated to 70°C was poured into the glass filter and filtered by suction to obtain the cake. 【0105】 The obtained cake and deionized water at a bath ratio of 10 were placed in an autoclave equipped with a stirrer, and acetic acid was added at a concentration of 11% by weight relative to PPS (19.8 mol% relative to PAS). After purging the inside of the autoclave with nitrogen, the temperature was raised to 195°C and held for 30 minutes. The autoclave was then cooled and the contents were removed. The contents were filtered by suction using a glass filter, and then deionized water at a bath ratio of 10 heated to 70°C was poured in and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PAS. 【0106】 Step 4 The obtained dried PAS was placed in an autoclave with a stirrer, NMP was added to a bath ratio of 5, and stirred at 95°C for 30 minutes. Then, the cake was obtained by suction filtration through a glass filter. The cake was washed with NMP at a bath ratio of 2, replaced with deionized water, and the resulting wet cake was vacuum dried at 130°C for 4 hours to obtain dried PAS. The properties of the obtained PPS are shown in Table 1. 【0107】 [Example 2] Following step 2 of Example 1, dried PPS was obtained in the same manner except that the water vapor atmosphere temperature during flashing was 220°C. The properties of the obtained PPS are shown in Table 1. 【0108】[Example 3] In an autoclave equipped with a stirrer and a bottom valve, 118.03 g (1.00 mol) of 47.5% sodium hydroxide, 41.04 g (1.00 mol) of 96% sodium hydroxide, 208.17 g (2.10 mol) of N-methyl-2-pyrrolidone (NMP), 27.07 g (0.33 mol) of sodium acetate, and 78.57 g of deionized water were charged. The mixture was gradually heated to 225°C over approximately 3 hours at atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling was started when 140.57 g of water and 4.00 g of NMP were distilled off. At this point, the amount of hydrogen sulfide distilled off was 0.02 mol, so the amount of sulfidating agent in the system after this process was 0.98 mol. 【0109】 Step 1: The mixture was then cooled to 160°C, and 147.24 g (1.00 mol) of p-dichlorobenzene (p-DCB) and 79.30 g (0.80 mol) of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised from 200°C to 240°C at a rate of 0.6°C / min while stirring. After that, the temperature was raised from 240°C to 276°C at a rate of 0.8°C / min and the reaction was carried out for 130 minutes. 【0110】 Step 2 Next, the autoclave temperature was lowered at a rate of 0.5°C / min. When it reached 250°C, the valve connected to the top lid was opened, and the steam was cooled and collected in a separate tank. The composition of the collected liquid was 5.4 g of water, 0.3 g of NMP, and 0.7 g of p-DCB. The amount of water in the system was 0.70 moles per 1.00 mole of sulfidizing agent added in Step 1. 【0111】 After deliquidation, the mixture was cooled to below 100°C to obtain a polymerization mixture. The obtained polymerization mixture was dried in an oven at 230°C under nitrogen to remove most of the NMP. 【0112】 Step 3 The recovered material and ion-exchanged water with a bath ratio of 10 were placed in an autoclave with a stirrer, washed at 70°C for 30 minutes, and then filtered by suction using a glass filter. Next, ion-exchanged water with a bath ratio of 10 heated to 70°C was poured into the glass filter and filtered by suction to obtain the cake. 【0113】The obtained cake and deionized water at a bath ratio of 10 were placed in an autoclave equipped with a stirrer, and acetic acid was added at a concentration of 11% by weight relative to PPS (19.8 mol% relative to PAS). After purging the inside of the autoclave with nitrogen, the temperature was raised to 195°C and held for 30 minutes. The autoclave was then cooled and the contents were removed. The contents were filtered by suction using a glass filter, and then deionized water at a bath ratio of 10 heated to 70°C was poured in and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PAS. 【0114】 Step 4 The obtained dried PAS was placed in an autoclave with a stirrer, NMP was added to a bath ratio of 5, and stirred at 95°C for 30 minutes. Then, the cake was obtained by suction filtration through a glass filter. The cake was washed with NMP at a bath ratio of 2, replaced with deionized water, and the resulting wet cake was vacuum dried at 130°C for 4 hours to obtain dried PAS. The properties of the obtained PPS are shown in Table 1. 【0115】 [Example 4] The liquid recovered in step 2 of Example 3 consisted of 15.7 g of water, 0.8 g of NMP, and 1.8 g of p-DCB. The amount of water in the system was 0.13 moles per 1.00 mole of sulfidizing agent added in step 1. Dry PPS was obtained in the same manner as in Example 3, except that drying in an oven was not performed. The properties of the obtained PPS are shown in Table 1. 【0116】 [Example 5] In an autoclave equipped with a stirrer and a bottom valve, 118.03 g (1.00 mol) of 47.5% sodium hydroxide, 41.04 g (1.00 mol) of 96% sodium hydroxide, 208.17 g (2.10 mol) of N-methyl-2-pyrrolidone (NMP), 27.07 g (0.33 mol) of sodium acetate, and 78.57 g of deionized water were charged. The mixture was gradually heated to 225°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling was started when 140.57 g of water and 4.00 g of NMP were distilled off. At this point, the amount of hydrogen sulfide distilled off was 0.02 mol, so the amount of sulfidating agent in the system after this process was 0.98 mol. 【0117】Step 1: The mixture was then cooled to 160°C, and 147.24 g (1.00 mol) of p-dichlorobenzene (p-DCB) and 79.30 g (0.80 mol) of NMP were added. The reaction vessel was then sealed under nitrogen gas and heated to 200°C while stirring. When 200°C was reached, 3.6 g (0.20 mol) of deionized water was injected under pressure. The temperature was raised from 200°C to 240°C at a rate of 0.6°C / min, and then from 240°C to 276°C at a rate of 0.8°C / min, and the reaction was allowed to proceed for 130 minutes. 【0118】 Step 2 Next, the autoclave temperature was lowered at a rate of 0.5°C / min. When it reached 250°C, the valve connected to the top lid was opened, and the steam was cooled and collected in a separate tank. The composition of the collected liquid was 9.2 g of water, 1.0 g of NMP, and 0.5 g of p-DCB. The amount of water in the system was 0.69 moles per 1.00 mole of sulfidizing agent used in Step 1. 【0119】 After deliquidation, the mixture was cooled to below 100°C to obtain the polymerization mixture. 【0120】 Step 3 The recovered material and ion-exchanged water with a bath ratio of 10 were placed in an autoclave with a stirrer, washed at 70°C for 30 minutes, and then filtered by suction using a glass filter. Next, ion-exchanged water with a bath ratio of 10 heated to 70°C was poured into the glass filter and filtered by suction to obtain the cake. 【0121】 The obtained cake and deionized water at a bath ratio of 10 were placed in an autoclave equipped with a stirrer, and acetic acid was added at a concentration of 11% by weight relative to PPS (19.8 mol% relative to PAS). After purging the inside of the autoclave with nitrogen, the temperature was raised to 195°C and held for 30 minutes. The autoclave was then cooled and the contents were removed. The contents were filtered by suction using a glass filter, and then deionized water at a bath ratio of 10 heated to 70°C was poured in and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PAS. 【0122】Step 4 The obtained dried PAS was placed in an autoclave with a stirrer, NMP was added to a bath ratio of 5, and stirred at 95°C for 30 minutes. Then, the cake was obtained by suction filtration through a glass filter. The cake was washed with NMP at a bath ratio of 2, replaced with deionized water, and the resulting wet cake was vacuum dried at 130°C for 4 hours to obtain dried PAS. The properties of the obtained PPS are shown in Table 1. 【0123】 [Comparative Example 1] Dried PPS was obtained in the same manner as in Example 1, except that step 4 was omitted. The properties of the obtained PPS are shown in Table 2. 【0124】 [Comparative Example 2] Dried PPS was obtained in the same manner as in Example 1, except that deliquidation was not performed in step 2. The properties of the obtained PPS are shown in Table 2. 【0125】 [Comparative Example 3] Dried PPS was obtained in the same manner as in Example 1, except that deliquidation was not performed in step 2 and step 4 was not carried out. The properties of the obtained PPS are shown in Table 2. 【0126】 [Comparative Example 4] Dry PPS was obtained in the same manner as in Example 3, except that the polymerization mixture was dried in an oven at 240°C under nitrogen in step 2. The properties of the obtained PPS are shown in Table 2. 【0127】 [Comparative Example 5] In an autoclave, 9.44 kg (80 mol) of 47.0% sodium hydroxide, 3.43 kg (82.4 mol) of 96% sodium hydroxide, 13.0 kg (131 mol) of N-methyl-2-pyrrolidone (NMP), 1.86 kg (22.6 mol) of sodium acetate, and 12 kg of deionized water were charged. The mixture was gradually heated to 235°C over approximately 3 hours at atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling began when 17.0 kg of water and 0.3 kg (3.23 mol) of NMP had been distilled out. At this point, the amount of hydrogen sulfide released was 2 mol. 【0128】Next, 11.9 kg (80.7 mol) of p-dichlorobenzene (p-DCB) and 10.5 kg (106 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring, the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min, and the reaction was continued at 270°C for 140 minutes. Then, while cooling to 240°C over 20 minutes, 2.67 kg (148 mol) of water was added to the system, and then the system was cooled from 240°C to 210°C at a rate of 0.4°C / min. After that, it was rapidly cooled to near room temperature. 【0129】 The contents were removed, diluted with NMP at a bath ratio of 4, and then the solvent and solids were filtered off using a sieve (80 mesh). The resulting particles were again diluted with NMP at a bath ratio of 4 and filtered. After that, the mixture was washed and filtered with water heated to 70°C at a bath ratio of 8. 【0130】 The obtained cake and deionized water with a bath ratio of 8 were placed in an autoclave equipped with a stirrer, and acetic acid was added to 0.5% by weight relative to PPS (0.9 mol% relative to PAS). After purging the inside of the autoclave with nitrogen, the temperature was raised to 75°C and held for 30 minutes. The autoclave was then cooled and the contents were removed. The contents were filtered by suction using a glass filter, and then deionized water with a bath ratio of 8 at 70°C was poured in and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PAS. The properties of the obtained PPS are shown in Table 2. 【0131】 [Comparative Example 6] 118.03 g (1.00 mol) of 47.5% sodium hydroxide, 41.04 g (1.00 mol) of 96% sodium hydroxide, 208.17 g (2.10 mol) of N-methyl-2-pyrrolidone (NMP), 24.62 g (0.33 mol) of sodium acetate, and 78.57 g of deionized water were charged into an autoclave. The mixture was gradually heated to 225°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling began when 140.57 g of water and 4.00 g of NMP were distilled off. At this point, the amount of hydrogen sulfide released was 0.02 mol, so the amount of sulfidating agent in the system after this process was 0.98 mol. 【0132】The mixture was then cooled to 160°C, and 147.24 g (1.00 mol) of p-dichlorobenzene (p-DCB) and 79.30 g (0.80 mol) of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised from 200°C to 221°C at a rate of 1.0°C / min while stirring, then raised to 238°C at a rate of 0.6°C / min, and then heated at a constant temperature of 238°C for 35 minutes, before being raised from 238°C to 250°C at a rate of 0.8°C / min. Next, the temperature was raised to 270°C at a rate of 0.8°C / min, and the reaction was continued at 270°C for 120 minutes. After heating for 120 minutes, 0.80 mol of deionized water was injected under pressure. The temperature was then lowered to 250°C at a rate of 1.2°C / min, then lowered to 215°C at a rate of 0.4°C / min, and finally lowered to 200°C at a rate of 1.0°C / min for granulation. It was then rapidly cooled to near room temperature. 【0133】 The contents were removed, diluted with NMP at a bath ratio of 4, and then the solvent and solids were filtered off using a sieve (80 mesh). The resulting particles were again diluted with NMP at a bath ratio of 4 and filtered. After that, the mixture was washed and filtered with water heated to 70°C at a bath ratio of 8. 【0134】 The obtained cake and deionized water with a bath ratio of 8 were placed in an autoclave equipped with a stirrer, and acetic acid was added to 0.5% by weight relative to PPS (0.9 mol% relative to PAS). After purging the inside of the autoclave with nitrogen, the temperature was raised to 75°C and held for 30 minutes. The autoclave was then cooled and the contents were removed. The contents were filtered by suction using a glass filter, and then deionized water with a bath ratio of 8 at 70°C was poured in and filtered by suction to obtain the cake. The obtained cake was dried at 120°C under a nitrogen stream to obtain dried PAS. The properties of the obtained PPS are shown in Table 2. 【0135】 【0136】 【0137】 The results of the above-mentioned examples and comparative examples will be explained in comparison. 【0138】In Example 1, step 2 was performed, and after recovery by the flash method, steps 3 and 4 were carried out. As a result, PAS with high molecular weight, low halogen end ratio, and high purity (low cyclic content) was obtained. Therefore, it exhibits excellent mechanical strength and low mold fouling when molded. 【0139】 In Example 2, the ambient temperature during flashing was increased to 220°C compared to Example 1. As a result, the specific surface area at the end of step 3 was greatly improved, and impurities were efficiently removed in the subsequent cleaning step. Compared to Example 1, the proportion of halogen ends, chloroform extraction amount, and cyclic PAS amount were further reduced, resulting in superior low mold fouling performance. 【0140】 In Example 3, after carrying out step 2, the solid was recovered by rapid cooling, the solvent was removed by distillation at 230°C, and then steps 3 and 4 were carried out. A PAS was obtained that possessed high molecular weight, a low proportion of halogen ends, and high purity (low amount of cyclic material), and exhibited excellent mechanical strength and low mold fouling when molded. 【0141】 In Example 4, more dewatering was performed than in Example 3, resulting in the acquisition of a PAS with an even lower halogen end ratio. 【0142】 In Example 5, water was added during polymerization in step 1 to promote a higher degree of polymerization, and then the water content was reduced by dewatering. The subsequent steps were carried out in the same manner as in Example 3. As a result, a PAS was obtained with a large proportion of high molecular weight halogen ends, a low amount of chloroform extract, and a low amount of cyclic PAS. 【0143】 In Comparative Example 1, because step 4 was not performed compared to Example 1, the halogen content was high and the purity was low (high cyclic content). As a result, there were problems such as excessive mold contamination during molding and a large amount of halogen remaining in the molded product. 【0144】 In Comparative Example 2, since step 2 was not performed, the particle size increased, reducing the cleaning effect, and resulting in an increase in the amount of cyclic material and chloroform extracted, which led to worsening mold contamination and an increase in gas volume. In addition, the halogen end reduction effect of step 2 was absent, and the proportion of halogen ends increased. 【0145】In Comparative Example 3, steps 2 and 4 were not performed, resulting in high halogen end-capacity, cyclic amount, and chloroform extraction amount. This leads to problems such as excessive mold contamination during molding and a large amount of halogen remaining in the molded product. 【0146】 Comparative Example 4 was carried out in the same manner as in Example 3, except that the solvent was removed by distillation at 240°C. Because the solid temperature exceeded 230°C, the specific surface area decreased, and the amount of chloroform extracted and the amount of cyclic material increased significantly. This PAS resulted in mold contamination problems. 【0147】 In Comparative Example 5, PAS was obtained by the quench method. The quench method is a slow-cooling recovery method, which makes it easier to achieve high purity, and the amount of chloroform extracted and the amount of cyclic PAS are small. However, because it is recovered by slow cooling, the dihalogenated aromatic compound and the active end react last, and the terminal chlorine level increases significantly. Also, compared to Example 1, the proportion of cyclic PAS with repeating units 7-8 was lower, resulting in poorer fluidity. 【0148】 In Comparative Example 6, PAS was obtained by the quench method. The quench method is a slow-cooling recovery method, which makes it easier to achieve high purity, and the amount of chloroform extracted and the amount of cyclic PAS are small. However, because it is recovered by slow cooling, the dihalogenated aromatic compound and the active end react last, resulting in a large increase in terminal chlorine. Also, compared to Example 5, the proportion of cyclic PAS with repeating units 7-8 was smaller, resulting in poorer fluidity. 【0149】 As described above, by carrying out steps 2 and 4, PAS with a low halogen end ratio and high purity can be obtained in a relatively simple manner, and due to its low gas and high purity characteristics, it can reduce contamination and surface defects remaining in molds when used for molding, etc.

Claims

1. A polyarylene sulfide having a weight-average molecular weight of 20,000 or more and 90,000 or less, a chloroform extract amount of 0.50% by weight or less, and a halogenated end ratio of 20% or less to the total end.

2. The polyarylene sulfide according to claim 1, wherein the weight-average molecular weight is 40,000 or more and 90,000 or less.

3. The polyarylene sulfide according to claim 1, wherein the proportion of halogen ends to the total ends is 15% or less.

4. The polyarylene sulfide according to any one of claims 1 to 3, wherein the amount of cyclic polyarylene sulfide having 4 to 6 repeating units is 0.15% by weight or less.

5. The polyarylene sulfide according to any one of claims 1 to 3, wherein the amount of cyclic polyarylene sulfide having 4 to 6 repeating units is 0.10% by weight or less.

6. A particulate polyarylene sulfide, the polyarylene sulfide according to any one of claims 1 to 3, wherein the median diameter is 300 μm or less.

7. The polyarylene sulfide according to any one of claims 1 to 3, wherein the proportion of cyclic polyarylene sulfide with 7 to 8 repeating units relative to the amount of cyclic polyarylene sulfide with 4 to 14 repeating units is 45% by weight or more.

8. A resin composition comprising a polyarylene sulfide according to any one of claims 1 to 3, with a filler or additive added.

9. A molded article obtained by molding the resin composition described in claim 8.

10. A water-related component molded from the resin composition described in claim 8.

11. A powder coating using the polyarylene sulfide described in any one of claims 1 to 3.

12. A fiber spun from polyarylene sulfide according to any one of claims 1 to 3.

13. A film obtained by molding a polyarylene sulfide according to any one of claims 1 to 3.

14. A method for producing polyarylene sulfide, comprising: step 1 of polymerizing a sulfidating agent and a dihalogenated aromatic compound in an organic polar solvent in the presence of a polymerization stabilizer, the method comprising: step 1 of polymerizing at 250°C or higher; step 2 of deliquidating after step 1; step 3 of washing the polymer obtained from the polymerization reaction with water or acid or both and then drying it; and step 4 of washing the dried polymer with an organic solvent.

15. The method for producing polyarylene sulfide according to claim 14, wherein step 2 is carried out after the conversion rate of the dihalogenated aromatic compound in step 1 reaches 95% or more.

16. The method for producing polyarylene sulfide according to claim 14, wherein the amount of water in the reaction system in step 2 is 0.80 moles or less per 1.00 mole of sulfidizing agent added in step 1.

17. The method for producing polyarylene sulfide according to claim 14, wherein a step of distilling off the organic polar solvent and recovering the solid is performed between step 2 and step 3.

18. A method for producing polyarylene sulfide according to claim 17, wherein the ambient temperature when distilling off the organic polar solvent is 230°C or lower, and the temperature of the recovered solid is 230°C or lower.

19. A method for producing polyarylene sulfide according to any one of claims 14 to 18, wherein the temperature of the solid material is kept below 230°C from step 3 to step 4.

20. A resin composition obtained by a manufacturing method according to any one of claims 14 to 18, to which a filler or additive has been added.

21. A molded article obtained by molding the resin composition described in claim 20.

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