JP2011132518A - Method of producing polyarylene sulfide and extrusion molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of efficiently and easily producing a high-molecular weight polyarylene sulfide with little amount of volatile component. <P>SOLUTION: In the method of producing polyarylene sulfide, a sulfurizing agent and a dihalogenated aromatic compound are allowed to react with each other in the presence of a polymerization additive in the temperature range of 200 to <280°C in an organic polar solvent, wherein in a process 1, a polymerization time (T1) in the temperature range of 200 to <245°C is 1.5 to <4 h, and the polymerization time (T1a) in the temperature range of 230 to <245°C is 30 min to <3.5 h, and the reaction is performed such that the conversion ratio of the dihalogenated aromatic compound at the time of process completion becomes 70 to 99 mol%, and in a process 2, the reaction is performed such that the polymerization time (T2) including temperature rising and falling time is 5 min to <2 h in the temperature range of 245 to <280°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing polyarylene sulfide (hereinafter abbreviated as PAS) and an extrusion-molded product, and more particularly to a method and an extrusion-molded product for efficiently and simply producing PAS with a small amount of volatile components. is there.

  Polyarylene sulfides (hereinafter abbreviated as PAS), represented by polyphenylene sulfide (hereinafter abbreviated as PPS), have heat resistance, chemical resistance, flame resistance, mechanical strength, electrical insulation, moisture and heat resistance, and dimensional stability. It is an excellent engineering plastic and can be molded into various molded products, films, sheets and fibers by various molding methods such as injection molding, extrusion molding and compression molding. Widely used in the field.

  As a method for producing PAS, Patent Document 1 discloses that a sulfidizing agent such as sodium sulfide is reacted with a dihalogenated aromatic compound such as p-dichlorobenzene in an organic amide solvent such as N-methyl-2-pyrrolidone. Although a method has been proposed, only PAS having a low molecular weight and a low melt viscosity can be obtained by this method. Such a low molecular weight PAS can be increased in molecular weight by heating in the presence of air after polymerization and oxidative curing (curing), but the cured PAS thus obtained has poor mechanical properties. Since it is sufficient and not linear, it has been difficult to form a sheet, film, fiber, or the like.

  In recent years, in order to obtain a high molecular weight PAS at the time of polymerization, various production methods improved from the above method have been proposed. As a means for improving the polymerization method of PAS, a method of adding various polymerization assistants when reacting a sulfidizing agent and a dihalogenated aromatic compound in an organic amide solvent is typical. A method using an alkali metal carboxylate as an auxiliary agent (Patent Document 2), a method using an alkaline earth metal salt of an aromatic carboxylic acid (Patent Document 3), and a method using an alkali metal halide (Patent Document 2) 4) and a method using a sodium salt of an aliphatic carboxylic acid (Patent Document 5) and the like have been proposed.

  According to these methods, it is possible to obtain linear and high molecular weight PAS by polymerization. However, in order to obtain a high degree of polymerization PAS in a shorter time, expensive such as lithium acetate and sodium benzoate are used. It is necessary to carry out the polymerization using a polymerization aid, and even if an inexpensive polymerization aid such as sodium acetate is simply applied, there is a problem that the polymerization time is long and it is economically disadvantageous.

  On the other hand, Patent Document 6 proposes to employ a specific two-stage polymerization method in a method of obtaining PAS by reacting a sulfidizing agent and a dihalogenated aromatic compound in an organic amide solvent. That is, this method is a dihalogenated aromatic by reacting at a temperature of 180 to 235 ° C. in the presence of 0.5 to 2.4 mol of water per 1 mol of the charged sulfiding agent in the pre-stage polymerization step. After producing a low-viscosity prepolymer with the conversion rate of the compound being 50 to 98 mol%, in the subsequent polymerization step, 2.5 to 7 mol of water is present per mol of the charged sulfiding agent. This is a two-stage polymerization method in which water is added to the reaction system and the temperature is raised to 245 to 290 ° C. and the reaction is continued. In this method, in order to obtain a sufficiently high molecular weight PAS, There was a problem of requiring a long polymerization time.

  Furthermore, Patent Document 7 discloses that an alkali metal carboxylate is present in a relatively small amount of 0.001 to 0.20 mol in the presence of 0.5 to 2.4 mol of water per mol of the sulfidizing agent. Although a method for carrying out polymerization is disclosed, the main purpose of this method is to increase the yield by precipitating granular PAS. With such a small amount of alkali metal carboxylate used, It was difficult to obtain PAS having a polymerization degree in a short time.

  Further, in Patent Documents 8 to 10, a low-viscosity prepolymer is produced in the former polymerization step, and then an alkali metal hydroxide, a polyhaloaromatic compound, a polyphenol salt, or the like is added in the latter polymerization step. Although a method for increasing the molecular weight is shown, an operation of adding a solid to the reaction solution in a high-pressure state is required, and an industrially complicated operation is required.

  In Patent Document 11 and Patent Document 12, a method of increasing the molecular weight by generating a low-viscosity prepolymer in the former polymerization step and then removing a part of the solvent and lowering the solvent ratio in the latter polymerization step. As shown, a step of solvent removal is necessary, which is industrially disadvantageous.

  Patent Document 13 discloses a method of increasing the molecular weight by generating a low-viscosity prepolymer in the pre-stage polymerization step and then adding oxygen in the post-stage polymerization step, but it is based on oxidative curing (cure). Since it has a high molecular weight, mechanical properties are insufficient, and since it is not linear, it has been difficult to form a sheet, film, fiber, or the like.

  Patent Document 14 discloses a method in which a low-viscosity prepolymer is produced in the pre-stage polymerization step, and then the remaining monomers and oligomers are washed away with an organic solvent to increase the molecular weight in the post-stage polymerization step. A filtration step accompanying solvent washing was necessary, and industrially complicated operations were required.

  In Patent Document 15 and Patent Document 16, a low-viscosity prepolymer is produced in the pre-stage polymerization step, and then a polymerization aid is used in the post-stage polymerization step to adjust the water content and polymerization temperature conditions. A method of molecular weighting is shown.

  However, sufficient melt stability is not obtained for use in extrusion molding and the like, and since there are many volatile components, there has been a problem that mold contamination and mold vent clogging are caused and production efficiency deteriorates.

  In addition, Patent Document 17 discloses a method in which a reaction solution immediately after polymerization is subjected to an acid treatment and then an alkali treatment in order to improve the melt stability of PAS. The operation was complicated.

  On the other hand, PAS with high melt fluidity that can cope with molded products with complex shapes is demanded, but PAS with high melt fluidity generally contains a large amount of low molecular weight components, so the amount of volatile components at the time of melting is high. Many tend to be. Since such a volatile component causes a problem that mold contamination or mold vent clogging is caused and production efficiency is deteriorated, a PAS having a high melt fluidity and a small amount of volatile components at the time of melting has been strongly demanded. As a method for reducing the amount of volatile components generated when PAS is melted, a method of washing the PAS slurry obtained after the reaction with an organic solvent such as acetone or NMP is generally known. Since the low molecular weight substance which is the main component of the sex component is removed by washing and the oligomer is also removed, the fluidity when PAS is melted tends to be lowered. Therefore, studies have been made to reduce the amount of volatile components in a state where a specific amount of oligomer is included and high melt fluidity is ensured. For example, in Patent Document 18, a polyhalogen aromatic compound and a sulfidizing agent are reacted in a polar organic solvent and then recovered by a flash method, and the resulting polymer is acid-treated at pH = 2-8 and 80-200 ° C. In addition, a method is disclosed in which the obtained PPS is heat-treated at 160 to 270 ° C. for 0.2 to 50 hours in an atmosphere having an oxygen concentration of 2% by volume or more. However, this method requires a heat treatment step, and requires an industrially complicated operation.

Japanese Examined Patent Publication No. 45-3368 (Claims, Examples) Japanese Patent Publication No. 52-12240 (Claims, Examples) JP 59-219332 (Claims, Examples) U.S. Pat. No. 4,038,263 (claims, examples) Japanese Patent Laid-Open No. 1-161022 (Claims, Examples) Japanese Patent Publication No. 63-33775 (Claims, Examples) JP-A-6-145355 (Claims, Examples) International Publication No. 2006/46748 (Claims, Examples) JP-A-5-271414 (Claims, Examples) JP-A-5-156014 (Claims, Examples) JP-A-6-49208 (Claims, Examples) JP 2002-284876 A (claims, examples) JP 2001-172387 A (Claims, Examples) JP-A-2-102228 (Claims and Examples) JP 2005-54169 A (claims, examples) JP-A-2002-265604 (Claims, Examples) JP-A-8-198965 (Claims, Examples) JP2009-144141 (Claims, Examples)

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue.

  Accordingly, an object of the present invention is to provide a method for producing a PAS having a small amount of volatile components industrially advantageously without going through a particularly complicated process.

  As a result of intensive studies to solve such problems, the present invention, when reacting a sulfidizing agent and a dihalogenated aromatic compound in the presence of a polymerization aid in an organic polar solvent, under specific temperature conditions. It was found that by reacting for a specific time, a PAS with a small amount of volatile components can be produced efficiently and simply, and the present invention has been achieved.

That is, the present invention relates to a method for producing polyarylene sulfide, in which a sulfidizing agent and a dihalogenated aromatic compound are reacted in a temperature range of 200 ° C. or higher and lower than 280 ° C. in the presence of a polymerization aid in an organic polar solvent. The present invention provides a method for producing a polyarylene sulfide, characterized by performing at least the following steps 1 and 2.
Step 1: When reacting a sulfidizing agent and a dihalogenated aromatic compound in the presence of a polymerization aid in an organic polar solvent, a polymerization time including a temperature increase / decrease time within a temperature range of 200 ° C. or higher and lower than 245 ° C. (T1) is 1.5 hours or more and less than 4 hours, and in the temperature range of 230 ° C. or more and less than 245 ° C., the polymerization time (T1a) including the temperature rise / fall time is 30 minutes or more and less than 3.5 hours, A step of reacting the dihalogenated aromatic compound at the end of the step so as to have a conversion rate of 70 to 99 mol% to form a polyarylene sulfide prepolymer, and step 2: a temperature range of 245 ° C. or higher and lower than 280 ° C. In the process, the prepolymer is converted to high molecular weight polyarylene sulfide by reacting in a polymerization time (T2) including a temperature increase / decrease time of 5 minutes or more and less than 2 hours.

  In the method for producing polyarylene sulfide of the present invention, a sulfidizing agent and a dihalogenated aromatic compound are reacted in an organic polar solvent within a temperature range of 200 ° C. or higher and lower than 280 ° C. in the presence of a polymerization aid. In the method for producing polyarylene sulfide, water is added to the reaction system so that the amount of water in the system in Step 2 is in a state where 0.8 mol or more and less than 3 mol of water is present per mol of the charged sulfidizing agent. And the molar ratio of water to polymerization aid [polymerization aid amount (mole) / water content (mole)] is 0.05 to 0.5 to convert the prepolymer to high molecular weight polyarylene sulfide. It is preferable.

  Furthermore, in the method for producing polyarylene sulfide of the present invention, it is preferable that the ratio (T1 / T2) of the polymerization time (T1) in step 1 to the polymerization time (T2) in step 2 is 1.2 or more. It is.

  In addition, the polyarylene sulfide is recovered by a quench method, and the dihalogenated aromatic compound present in the reaction system at the start of Step 1 is 0.9 mol or more and less than 1.5 mol with respect to 1 mol of the sulfidizing agent. The amount of water in the organic amide solvent in Step 1 is 0.5 or more and less than 1.5 moles per mole of the sulfidizing agent charged; polymerization present in the reaction system at the start of Step 1 The auxiliary agent is 0.1 mole or more and less than 0.7 mole relative to 1 mole of the sulfidizing agent, and the alkali metal hydroxide present in the reaction system at the start of the step 1 is based on 1 mole of the sulfidizing agent. Preferred conditions are 0.9 mol or more and less than 1.2 mol, and the organic polar solvent used in the reaction is 2.5 mol or more and less than 5.5 mol with respect to 1 mol of the sulfidizing agent. .

  According to the present invention, a polyarylene sulfide having a small amount of volatile components can be efficiently produced in a short time.

  The PAS in the present invention is a homopolymer or copolymer having a repeating unit of the formula, — (Ar—S) —, as a main constituent unit, and preferably containing 80 mol% or more of the repeating unit. Ar includes units represented by the following formulas (A) to (J), among which the formula (A) is particularly preferable.

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.)

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

  The PAS in the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the above repeating unit.

  Typical examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ether, random copolymers thereof, block copolymers, and mixtures thereof. Particularly preferred PASs include p-phenylene sulfide units as the main structural unit of the polymer.

Of polyphenylene sulfide, polyphenylene sulfide sulfone, and polyphenylene sulfide ether containing 80 mol% or more, particularly 90 mol% or more. Polyphenylene sulfide is particularly preferable.

  Regarding the PAS production method of the present invention, the sulfidizing agent, organic polar solvent, dihalogenated aromatic compound, polymerization aid, branching / crosslinking agent, molecular weight regulator, polymerization stabilizer, pre-process, polymerization process, polymer Details will be given in the order of recovery, production PAS, other post-treatment, and application.

(1) Sulfiding agent Examples of the sulfiding agent used in the present invention include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more of these, and sodium sulfide is preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  Specific examples of the alkali metal hydrosulfide include, for example, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and a mixture of two or more of these. Preferably used. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  A sulfidizing agent prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Further, a sulfidizing agent can be prepared from alkali metal hydrosulfide and alkali metal hydroxide, and transferred to a polymerization tank for use.

  Alternatively, a sulfidizing agent prepared in situ in a reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used. Further, a sulfidizing agent can be prepared from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide, and transferred to a polymerization tank for use.

  In the present invention, the amount of the sulfidizing agent means the remaining amount obtained by subtracting the loss from the actual charge when there is a partial loss of the sulfidizing agent before the start of the polymerization reaction due to dehydration operation or the like. And

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

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time, and the amount used is 0.9 mol or more per mol of the alkali metal hydrosulfide. A range of less than 2 mol, preferably 0.95 mol or more and less than 1.15 mol, more preferably 1.0 mol or more and less than 1.1 mol can be exemplified. By setting it within this range, PAS having a small amount of polymerization by-products can be obtained without causing decomposition.

(2) Organic polar solvent In this invention, an organic polar solvent is used as a polymerization solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, and 1,3-dimethyl-2-imidazolide. Non-, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, dimethyl sulfone, tetramethylene sulfoxide, and other aprotic organic solvents, and mixtures thereof have high reaction stability. Are preferably used. Of these, N-methyl-2-pyrrolidone (NMP) is particularly preferably used.

  Although there is no restriction | limiting in particular in the usage-amount of the organic polar solvent used as a polymerization solvent of PAS in this invention, From a stable reactive and economical viewpoint, 2.5 mol or more and less than 5.5 mol per mol of sulfidizing agents, The range is preferably 2.5 mol or more and less than 5 mol, more preferably 2.5 mol or more and less than 4.5 mol.

(3) Dihalogenated aromatic compound Examples of the dihalogenated aromatic compound used in the present invention include dihalogenated benzenes such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, and p-dibromobenzene, and 1-methoxy- Examples thereof include dihalogenated aromatic compounds containing a substituent other than halogen such as 2,5-dichlorobenzene and 3,5-dichlorobenzoic acid. Especially, the dihalogenated aromatic compound which has p-dihalogenated benzene represented by p-dichlorobenzene as a main component is preferable. It is also possible to use a combination of two or more different dihalogenated aromatic compounds in order to produce a PAS copolymer.

  The amount of the dihalogenated aromatic compound used in the present invention is 0.9 mol or more and less than 1.5 mol per mol of the sulfidizing agent, from the viewpoint of effectively suppressing the decomposition and efficiently obtaining a PAS having a viscosity suitable for processing. Can be exemplified by a range of 0.95 mol or more and less than 1.1 mol, more preferably 1.002 mol or more and less than 1.05 mol.

(4) Polymerization aid In the present invention, a polymerization aid is used in order to obtain a high degree of polymerization PAS in a shorter time. Specific examples of polymerization aids include alkali metal carboxylates and lithium halides, organic sulfonate metal salts, alkali metal sulfates, alkaline earth metal oxides, and alkali metals that are generally known as polymerization aids for PAS. Examples thereof include phosphates and alkaline earth metal phosphates. These may be used alone or in combination of two or more. Particularly preferred are alkali metal carboxylates.

  The alkali metal carboxylate has a general formula R (COOM) n (wherein R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkylaryl group or an arylalkyl group. , Lithium, sodium, potassium, rubidium and cesium, and n is an integer of 1 to 3). Alkali metal carboxylates can also be used as anhydrous, hydrated or aqueous solutions. Specific examples of the alkali metal carboxylate include, for example, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. Can be mentioned. Alkali metal carboxylate is an organic acid, an organic acid, and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, with approximately equal chemical equivalents. You may form by adding and making it react one by one. Among the alkali metal carboxylates, lithium salts are highly soluble in the reaction system and have a large auxiliary effect, but are expensive, and potassium, rubidium, and cesium salts are estimated to be insufficiently soluble in the reaction system. Sodium acetate which is inexpensive and has an appropriate solubility in the reaction system is preferably used.

  The amount of these polymerization aids used is in the range of 0.10 mol to 0.7 mol, more preferably in the range of 0.15 to 0.60 mol, with respect to 1 mol of the charged sulfidizing agent. The range of 0.55 mol is more preferable, and the range of 0.25 to 0.50 mol is particularly preferable. If it is less than the above range, the effect of increasing the degree of polymerization is insufficient, and if it exceeds the above range, not only the effect of increasing the degree of polymerization can be obtained, but also the polymerization required to obtain a polymer of the same degree of polymerization. Conversely, the time becomes longer. A longer polymerization time leads to an increase in the amount of volatile components in the resulting PAS.

  These polymerization assistants are not particularly limited in their addition timing, and may be added at any time during the previous step, at the start of polymerization, or during polymerization, which will be described later, or may be added in a plurality of times. However, from the viewpoint of ease of addition, it is preferable to add it at the start of the previous step or at the start of polymerization.

  In order to enhance the effect of these polymerization aids, it is also one of preferred modes to add water at the stage of step 2 in the polymerization step described later. As a result, the effect as a polymerization aid can be further increased, and a high degree of polymerization PAS tends to be obtained in a short time even with a smaller amount of polymerization aid. In this case, the preferable range of water content in the polymerization system is 0.8 mol or more and less than 3 mol, and more preferably 1.0 mol or more and 2.5 mol or less with respect to 1 mol of the sulfidizing agent. If the amount of water is too large, the internal pressure of the reactor is greatly increased, and a reactor having high pressure resistance is required, which tends to be unfavorable in terms of economy and safety. The conversion rate of the dihalogenated aromatic compound in the stage of setting the water content in the polymerization system to the above range is 70 mol% or more, preferably 80% or more, more preferably 90% or more, and still more preferably 95%, as described later. The above is preferable.

  In addition, it is one of preferable modes to add water after polymerization. The preferable range of the water content in the polymerization system after adding water after the polymerization is 1 to 15 mol, and more preferably 1.5 to 10 mol, relative to 1 mol of the sulfidizing agent.

(5) Branching / crosslinking agent, molecular weight modifier In the present invention, in order to form a branched or crosslinked polymer, a polyhalogen compound (not necessarily an aromatic compound) that is trihalogenated or higher, an active hydrogen-containing halogenated compound. Branching / crosslinking agents such as aromatic compounds and halogenated aromatic nitro compounds can also be used in combination. As the polyhalogen compound, a commonly used compound can be used. Among them, polyhalogenated aromatic compounds are preferable, and specific examples include 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, Examples include 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 1,4,6-trichloronaphthalene, and among them, 1,3,5-trichlorobenzene and 1,2,4-trichlorobenzene are preferable. Examples of the active hydrogen-containing halogenated aromatic compound include halogenated aromatic compounds having functional groups such as amino group, mercapto group, and hydroxyl group. Specific examples include 2,5-dichloroaniline, 2,4-dichloroaniline, 2,3-dichloroaniline, 2,4,6-trichloroaniline, 2,2′-diamino-4,4′-dichlorodiphenyl ether, 2 , 4′-diamino-2 ′, 4-dichlorodiphenyl ether, and the like. Examples of the halogenated aromatic nitro compound include 2,4-dinitrochlorobenzene, 2,5-dichloronitrobenzene, 2-nitro-4,4′-dichlorodiphenyl ether, and 3,3′-dinitro-4,4′-. Examples include dichlorodiphenyl sulfone, 2,5-dichloro-2-nitropyridine, 2-chloro-3,5-dinitropyridine, and the like.

  In addition, a monohalogenated compound (not necessarily an aromatic compound) can be used in combination for the purpose of adjusting the molecular weight of PAS. Examples of the monohalogenated compound include monohalogenated benzene, monohalogenated naphthalene, monohalogenated anthracene, monohalogenated compounds containing two or more benzene rings, and monohalogenated heterocyclic compounds. Of these, monohalogenated benzene is preferable from the viewpoint of economy. It is also possible to use a combination of two or more different monohalogenated compounds.

(6) Polymerization stabilizer In the production of the PAS of the present invention, a polymerization stabilizer can be used in order to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilization of the polymerization reaction system and suppresses undesirable side reactions. One measure of the side reaction is the generation of thiophenol, and the addition of a polymerization stabilizer can suppress the generation of thiophenol. Specific examples of the polymerization stabilizer include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferable. Since the alkali metal carboxylate described above also acts as a polymerization stabilizer, it is one of the polymerization stabilizers used in the present invention. In addition, when an alkali metal hydrosulfide is used as a sulfidizing agent, it has been described above that it is particularly preferable to use an alkali metal hydroxide at the same time. Oxides can also be polymerization stabilizers.

  These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is usually used in a proportion of 0.001 to 0.2 mol, preferably 0.005 to 0.1 mol, relative to 1 mol of the sulfidizing agent in the reaction system before the start of the polymerization reaction. desirable. If this ratio is small, the stabilizing effect is insufficient. Conversely, if it is too large, it tends to be economically disadvantageous or the polymer yield tends to decrease. In addition, when a part of alkali metal sulfide decomposes | disassembles at the time of reaction and hydrogen sulfide generate | occur | produces, the alkali metal hydroxide produced | generated as a result can also become a polymerization stabilizer.

  The addition timing of the polymerization stabilizer is not particularly specified, and may be added at any time during the preceding step, at the start of the polymerization, or during the polymerization described later, and added in several times at any time. However, from the viewpoint of ease of addition, it is preferable to add at the start of the previous step or at the start of polymerization.

(7) Pre-process In the manufacturing method of PAS of this invention, although a sulfidizing agent is normally used in the form of a hydrate, before adding a dihalogenated aromatic compound, an organic polar solvent and a sulfidizing agent are included. It is preferable to raise the temperature of the mixture and remove excess water out of the system. In addition, when water is removed excessively by this operation, it is preferable to add and replenish the deficient water.

  Further, as described above, an alkali metal sulfide prepared from an alkali metal hydrosulfide and an alkali metal hydroxide in situ in the reaction system or in a tank different from the polymerization tank is also used as the sulfidizing agent. be able to. Although there is no particular limitation on this method, desirably, an alkali metal hydrosulfide and an alkali metal hydroxide are added to the organic polar solvent in an inert gas atmosphere at a temperature ranging from room temperature to 150 ° C., preferably from room temperature to 100 ° C. In addition, a method of raising the temperature to at least 150 ° C. or more, preferably 180 ° C. to 260 ° C. under normal pressure or reduced pressure, and distilling off the water can be mentioned. A polymerization aid may be added at this stage. Moreover, in order to accelerate | stimulate distillation of a water | moisture content, you may react by adding toluene etc.

  The amount of water in the system at the stage where the pre-process is completed is preferably 0.5 to 1.5 mol, more preferably 0.9 to 1.1 mol, per mol of the sulfidizing agent charged. preferable. Here, the amount of water in the system is an amount obtained by subtracting the amount of water removed from the system from the amount of water charged in the previous step. In addition, the water to be charged may be in any form such as water, an aqueous solution, and crystal water.

By defining the amount of coexisting water in such a relatively small range, a PAS having a high degree of polymerization can be obtained in a shorter time.

  After completion of the previous step, the reaction product prepared in the previous step and the dihalogenated aromatic compound are brought into contact with each other in an organic polar solvent, and the polymerization reaction step described below is performed in the same reactor as the previous step. Alternatively, the polymerization reaction step may be performed after the reactant prepared in the previous step is transferred to a reaction vessel different from the previous step.

(8) Polymerization step In the present invention, PAS is produced by reacting a sulfidizing agent and a dihalogenated aromatic compound in the presence of a polymerization aid in a temperature range of 200 ° C or higher and lower than 280 ° C in an organic polar solvent. In this case, the above reaction is performed by at least the following steps 1 and 2, but there may be additional steps such as dehydration and other pretreatment steps and posttreatment steps.

<Step 1> In the organic polar solvent, when the sulfidizing agent and the dihalogenated aromatic compound are reacted in the presence of the polymerization aid, the temperature increasing / decreasing time is included in the temperature range of 200 ° C. or higher and lower than 245 ° C. When the polymerization time (T1) is 1.5 hours or more and less than 4 hours and the temperature range is 230 ° C. or more and less than 245 ° C., the polymerization time (T1a) including the temperature rise / fall time is 30 minutes or more and less than 3.5 hours. A step of reacting the dihalogenated aromatic compound at the end of the step so that the conversion rate is 70 to 99 mol% to form a prepolymer of PAS, and <Step 2> a temperature of 245 ° C. or higher and lower than 280 ° C. Within the range, the polymerization time (T2) including the temperature rise / fall time is reacted for 5 minutes or more and less than 2 hours to convert the prepolymer to high molecular weight PAS,
By passing through this step, it is possible to efficiently obtain a high molecular weight PAS having a low amount of volatile components and excellent melt stability in a short time.

  Hereinafter, Step 1 and Step 2 will be described in detail.

  <Step 1> In the present invention, when the sulfidizing agent and the dihalogenated aromatic compound are polymerized in an organic polar solvent in the presence of an alkali metal hydroxide at a temperature range of 200 ° C. or higher and lower than 280 ° C., 200 ° C. It is necessary to perform step 1 in which the polymerization time (T1) including the temperature rise / fall time is 1.5 hours or more and less than 4 hours within the temperature range of 245 ° C. or less, preferably 2 hours or more and less than 4 hours, 2 hours or more and 3.5 hours or less are more preferable. When T1 is less than 1.5 hours, the conversion rate of the dihalogenated aromatic compound described later is too low, so that the unreacted sulfidizing agent causes decomposition of the prepolymer in Step 2 and sufficiently increases the degree of polymerization. Tend to be difficult. Moreover, when T1 exceeds 4 hours, it will lead to a reduction in production efficiency. The implementation of Step 1 is to polymerize a certain amount of dihalogenated aromatic compound to PAS before Step 2, and in the state where a large amount of unreacted dihalogenated aromatic compound in Step 1 is present. When shifted to 2, the unreacted sulfiding agent in Step 2 tends to cause degradation of the prepolymer.

  Further, in the polymerization in the range of 200 ° C. or more and less than 245 ° C., the polymerization time (T1a) including the temperature increase / decrease time must be 30 minutes or more and less than 3.5 hours in the temperature range of 230 ° C. or more and less than 245 ° C. It is. In order to obtain a PAS having a high melt stability which is the object of the present invention, it is preferable to carry out Step 2 after sufficiently increasing the conversion rate of the dihalogenated aromatic compound at a low temperature as in Step 1, but the polymerization temperature is 230. If the reaction is less than 0 ° C., the reaction rate is slow and the conversion rate of the dihalogenated aromatic compound is difficult to increase, and the melt viscosity of the PAS obtained by the recovery tends to be too low. Further, it takes a long time to increase the conversion rate of the dihalogenated aromatic compound by a reaction of less than 230 ° C., which is not preferable in terms of production efficiency. Therefore, it is preferable in terms of production efficiency to shorten the polymerization time in the temperature range of 200 ° C. or higher and lower than 230 ° C. and to promote the polymerization in the temperature range of 230 ° C. or higher and lower than 245 ° C. where the reaction rate is relatively high. More preferable polymerization time in the temperature range of 230 ° C. or more and less than 245 ° C. is 40 minutes or more and less than 3.5 hours, more preferably 1 hour or more and less than 3 hours, still more preferably 90 minutes or more and less than 3 hours, more preferably 100 minutes. For example, less than 3 hours can be exemplified. A preferable polymerization time in a temperature range of 200 ° C. or higher and lower than 230 ° C. is within 2 hours, and more preferably within 1 hour can be exemplified as a preferable time.

The average rate of temperature increase within the polymerization temperature range is preferably 0.1 ° C./min or more. The average rate of temperature increase is the time m required to raise the temperature section (provided that t2 <t1) from a certain temperature t2 (° C.) to a certain temperature t1 (° C.). From (minutes), the following average heating rate (° C./minute)=[t1 (° C.) − T2 (° C.)] / M (minutes)
Is the average speed calculated by Therefore, if it is within the range of the above average heating rate, it is not always necessary to have a constant rate, there may be a constant temperature section, and there is no problem even if the temperature is raised in multiple stages, and the essence of the present invention is impaired. As long as there is not, there may be a section which becomes a negative temperature rising rate temporarily.

  The average temperature rising rate is preferably 2.0 ° C./min or less, and more preferably 1.5 ° C./min or less. If the average heating rate is too high, it may be difficult to control the reaction, and more energy tends to be required to raise the temperature. When a vigorous reaction occurs at the initial stage of the reaction, it is preferable to carry out the reaction by a method in which the reaction is carried out to some extent at 240 ° C. or lower and then heated to a temperature exceeding 240 ° C.

In the present invention, it is necessary to react so that the conversion rate of the dihalogenated aromatic compound at the end of Step 1 is 70 to 99 mol% to form a PAS prepolymer, preferably 90 mol% or more, More preferably, the reaction is carried out so as to be 95 mol% or more. When the process shifts to step 2 with such a low conversion rate, the unreacted sulfiding agent tends to cause decomposition of the prepolymer and it is difficult to sufficiently increase the degree of polymerization. In addition, if the reaction is carried out until the pass-through rate in step 1 exceeds 99 mol%, a long polymerization time is required, leading to a decrease in production efficiency, and at the same time, a PAS having a high melt fluidity according to the present invention is obtained. Absent. The conversion rate of the dihalogenated aromatic compound (hereinafter abbreviated as DHA) is a value calculated by the following formula. The remaining amount of DHA can be usually determined by gas chromatography.
(A) When the dihalogenated aromatic compound is added in excess in a molar ratio with respect to the sulfidizing agent: Conversion = [[DHA charge (mol) -DHA remaining amount (mol)] / [DHA charge (mol)- DHA excess (mole)]] × 100%
(B) In cases other than the above (a) Conversion rate = [[DHA charge (mol) −DHA remaining amount (mol)] / [DHA charge (mol)]] × 100%.

  <Step 2> In the present invention, when the sulfidizing agent and the dihalogenated aromatic compound are polymerized in an organic polar solvent in the temperature range of 200 ° C. or higher and lower than 280 ° C. in the presence of an alkali metal hydroxide, Step 1 Subsequently, in the temperature range of 245 ° C. or more and less than 280 ° C., it is necessary to carry out a step of obtaining PAS by reacting in a polymerization time (T2) including a temperature increase / decrease time of 5 minutes or more and less than 2 hours. The final temperature in step 2 is preferably less than 275 ° C, more preferably 270 ° C or less. If the polymerization is terminated only in Step 1 without going through Step 2, the melt viscosity of PAS is too low, and it is often difficult to mold the resin. The effect of increasing the degree of polymerization is reduced, which is economically disadvantageous. Further, when the final temperature of step 2 reaches 280 ° C. or higher, the melt viscosity of PAS tends to be too high and the increase in the internal pressure of the reactor tends to increase, and a reactor having higher pressure resistance performance is required. Therefore, it is not preferable in terms of economy and safety.

  The polymerization time (T2) of step 2 in the present invention needs to be 5 minutes or more and less than 2 hours, preferably 10 minutes or more and less than 2 hours, more preferably 30 minutes or more and less than 2 hours, and more preferably 50 minutes or more. More preferably, it is less than 2 hours, and more preferable range is 50 minutes or more and less than 90 minutes. Alkali metal alkylamino produced by reacting an organic polar solvent such as NMP with an alkali metal hydroxide when a sulfidizing agent and a dihalogenated aromatic compound are reacted in the presence of an alkali metal hydroxide in an organic polar solvent. The alkyl carboxylate contributes as a side reaction during the polymerization reaction, but if the polymerization time (T2) in Step 2 is 2 hours or more, the side reaction proceeds remarkably and the obtained PAS is melted and heated. The amount of volatile components derived from the reaction product increases and tends to be inferior in melt stability. In addition, there is a problem that a long polymerization time causes a decrease in production efficiency.

  The reaction in step 2 may be a one-step reaction performed at a constant temperature, a multi-step reaction in which the temperature is raised stepwise, or a reaction in which the temperature is continuously changed.

  In particular, when the polymerization time (T2) in step 2 is 40 minutes or longer, a high molecular weight polyarylene sulfide having a low amount of volatile components excellent in melt stability can be efficiently produced in a short time. The arylene sulfide resin has a sufficiently high melt viscosity and excellent toughness, so that it is particularly useful as an extrusion-molded product and has an excellent surface appearance.

  In order to obtain a PAS having a high melt fluidity and a small amount of volatile components, the polymerization time (T1a) including the temperature rise / fall time in the temperature range of 230 ° C. or higher and lower than 245 ° C. The ratio (T1a / T2) is preferably 0.5 or more. The higher the ratio, the higher the conversion rate of the dihalogenated aromatic compound in the temperature range of 230 ° C. or higher and lower than 245 ° C., and at the same time, the polymerization time in Step 2 is reduced to a short time, and the high melt fluidity and low The amount of volatile components can be combined. Therefore, T1a / T2 is more preferably 0.7 or more, more preferably 1 or more, and even more preferably 2 or more. The upper limit of T1a / T2 is not particularly limited, but is preferably 25 or less, more preferably 20 or less, in order to obtain a PAS having preferable melt fluidity.

  In order to obtain a high molecular weight PAS having a low volatile component amount and excellent melt stability in the present invention, the ratio (T1 / T2) of the polymerization time (T1) in step 1 and the polymerization time (T2) in step 2 is set. It is preferable to be 1.2 or more.

  The higher the ratio, the more sufficient the polymerization time in Step 1 can be increased, and the conversion rate of the dihalogenated aromatic compound can be increased, and at the same time, the polymerization time in Step 2 can be suppressed to a short time and favorable melt fluidity can be secured. . Therefore, T1 / T2 is more preferably 1.2 or more, and even more preferably 1.5 or more. The upper limit of T1 / T2 is not particularly limited, but is preferably 30 or less, more preferably 25 or less, in order to obtain a PAS having preferable melt fluidity. Moreover, in order to obtain PAS excellent in melt stability, 6 or less is preferable and 5 or less is more preferable.

  Furthermore, in order to obtain the PAS of the present invention, the total reaction time (T1 + T2) from the start of step 1 to the end of step 2 is preferably less than 7 hours, more preferably less than 6 hours, and more preferably 5.5 hours It is more preferable to make it less than. Prolonging the polymerization time leads to a decrease in production efficiency and tends to cause a deterioration in melt stability.

  The amount of the polymerization aid in the above step 2 is preferably 0.10 to 0.70 mol per 1 mol of the charged sulfidizing agent. A more preferable range of the polymerization assistant amount is 0.15 to 0.60 mol, more preferably 0.20 to 0.55 mol, and particularly preferably 0.25 to 0.50 mol. If it is less than the above range, the effect of increasing the degree of polymerization is insufficient, and if it exceeds the above range, not only the effect of increasing the degree of polymerization beyond that can be obtained, but also an adverse effect on the polymerization time.

  These polymerization auxiliaries should just be contained in the reaction system in a back | latter stage polymerization process (the said process 2) at least. Therefore, the addition time may be added in several times before the dehydration step before the start of the pre-stage polymerization, during the start of the pre-stage polymerization or in the middle of the post-stage polymerization, or any combination thereof, From the viewpoint of ease of addition, it is preferable to add at the same time as the start of the previous step or the start of polymerization.

  In the above step 2, it is desirable to add water so that the amount of water in the polymerization system is 1.0 mol or more and 2.5 mol or less per mol of the charged sulfidizing agent. The addition timing of water may be any of the start time, the intermediate time, and the end time of the above process, but it is preferable to start the addition before half of the time required for the above process 2. If the amount of water is less than the above range, the effect of increasing the degree of polymerization decreases.On the other hand, if the amount exceeds the above range, not only the polymerization time becomes longer, but also the pressure in the polymerization vessel increases, Since a polymerization kettle having high pressure resistance is required, it is not preferable in terms of economy and safety.

In the step 2, it is preferable that the molar ratio of the water present in the reaction system and the polymerization assistant [polymerization assistant amount (mol) / water content (mol)] is 0.05 to 0.5. Even if this molar ratio is less than the above range or exceeds the above range, it is difficult to obtain a sufficiently high degree of polymerization PAS in a short time. A more preferable range of the molar ratio is 0.10 to 0.30.
Among them, water is added to the reaction system so that the amount of water in the above step 2 is 1.0 mol or more and 2.5 mol or less per mol of the charged sulfidizing agent, and the molar ratio of the water and the polymerization aid is set. Converting the prepolymer to a high molecular weight polyarylene sulfide with [polymerization aid amount (mole) / water content (mole)] of 0.05 to 0.5 provides a high degree of polymerization PAS in a short time. Preferred above.

  In this invention, the usage-amount (preparation amount) of a dihalogenated aromatic compound is 0.9-1.5 mol normally with respect to 1 mol of preparation sulfidizing agents, More preferably, it is 0.95-1.1 mol, More preferably Is preferably in the range of 1.002 to 1.05 mol in order to obtain a high molecular weight PAS. When this use ratio is less than 0.9 mol or more than 1.5 mol, it is difficult to obtain a PAS having a high viscosity (high polymerization degree) suitable for processing.

  By applying the method of the present invention, it is possible to obtain a PAS excellent in melt stability, excellent in polymerization degree and economical efficiency in a total polymerization reaction time range of 1 to 10 hours, particularly in a range of 4 to 8 hours. it can. Here, the total polymerization reaction time indicates the total time in which the polymerization system is in the range of 200 ° C. to 290 ° C. including the temperature raising, constant temperature, and temperature lowering processes after the monomer raw material is charged.

  For the polymerization of the present invention, known polymerization methods such as a batch method and a continuous method can be employed. Further, the atmosphere during polymerization is preferably a non-oxidizing atmosphere, preferably carried out in an inert gas atmosphere such as nitrogen, helium, and argon, and nitrogen is particularly preferred from the viewpoint of economy and ease of handling. . The reaction pressure is not particularly limited because it cannot be defined unconditionally depending on the type and amount of the raw material and solvent used, or the reaction temperature.

(9) Polymer recovery In the present invention, the post-treatment after completion of the polymerization reaction can be carried out by a conventional method. For example, after completion of the polymerization reaction, the polymerization solvent is volatilized and removed by flash method, followed by repeated washing with water and drying, and the filtered product slurry is filtered as it is or diluted with water. Then, PAS can be obtained by repeatedly washing with water and drying. The product slurry may be sieved through the polymer while still in the high temperature state. Further, after the filtration and sieving, the PAS may be washed with the same organic polar solvent as the polymerization solvent, an organic solvent such as ketones and alcohols, and high-temperature water. PAS can be treated with an acid such as acetic acid or hydrochloric acid or a salt such as ammonium chloride.

  In the production of the PAS of the present invention, after the completion of the polymerization step, PAS is recovered from the polymerization reaction product containing the PAS component and the solvent obtained in the polymerization step. As a recovery method, for example, a flash method, that is, a polymerization reaction product is flashed from a high-temperature and high-pressure (normally 250 ° C. or higher, 0.8 MPa or higher) state to an atmosphere of normal pressure or reduced pressure, and the polymer is powdered simultaneously with solvent recovery. Or the quenching method, that is, the polymerization reaction product is gradually cooled from a high temperature and high pressure state to precipitate the PAS component in the reaction system, and is filtered off at a temperature of 70 ° C. or higher, preferably 100 ° C. or higher. Thus, a method of recovering a solid containing a PAS component can be used.

  In the production of the PAS of the present invention, it is not limited to either the quench method or the flash method. However, since the PAS obtained by the flash method contains an oligomer component typified by a chloroform extract component, It is preferable to recover by the quench method for the purpose of particularly reducing the sex component or for the purpose of obtaining an extruded product. Further, for the purpose of obtaining PAS excellent in melt fluidity, it is preferable to recover by a flash method.

  The present invention may include a step of washing the obtained PAS with an organic solvent, and the method is as follows. The organic solvent used for washing the PPS resin in the present invention is not particularly limited as long as it does not have an action of decomposing the PPS resin. For example, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1, 3 -Nitrogen-containing polar solvents such as dimethylimidazolidinone, hexamethylphosphoramide, piperazinones, sulfoxide-sulfon solvents such as dimethyl sulfoxide, dimethyl sulfone, sulfolane, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, Ether solvents such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane, dichloroethane, teto Halogen solvents such as chloroethane, perchlorethane, chlorobenzene, alcohol / phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol, and benzene, Examples thereof include aromatic hydrocarbon solvents such as toluene and xylene. Among these organic solvents, use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform and the like is particularly preferable. These organic solvents are used alone or in combination of two or more.

  As a method of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent, and if necessary, stirring or heating can be appropriately performed. There is no restriction | limiting in particular about the washing | cleaning temperature at the time of wash | cleaning PPS resin with an organic solvent, Arbitrary temperature of about normal temperature-about 300 degreeC can be selected. Although the cleaning efficiency tends to increase as the cleaning temperature increases, a sufficient effect is usually obtained at a cleaning temperature of room temperature to 150 ° C. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. In particular, when a treatment involving heating is performed, it is preferably performed in an inert gas atmosphere such as nitrogen. There is no particular limitation on the cleaning time. Depending on the cleaning conditions, in the case of batch-type cleaning, a sufficient effect can be obtained usually by cleaning for 5 minutes or more. It is also possible to wash in a continuous manner.

  As a preferred embodiment of the flash method, a method in which the high-temperature and high-pressure polymerization reaction product obtained in the polymerization step is ejected from a nozzle into an atmosphere such as nitrogen or water vapor at normal pressure. In the flash method, the solvent can be efficiently recovered by utilizing the heat of vaporization of the solvent when the polymerization reaction product is flushed from the high temperature and high pressure state to the normal pressure state. Efficiency decreases and productivity deteriorates. Therefore, the temperature in the polymerization system when flushing, that is, the temperature of the polymerization reaction product is preferably 250 ° C. or higher, and more preferably 255 ° C. or higher. The temperature of the atmosphere such as nitrogen or water vapor when flushing under normal pressure is usually selected from 150 to 250 ° C. If the solvent recovery from the polymerization reaction product is insufficient, nitrogen or water vapor at 150 to 250 ° C. after flushing, etc. Heating may be continued under the atmosphere of

  Since the PAS obtained by such a flash method contains ionic impurities such as alkali metal halides and alkali metal organic substances, which are polymerization by-products, washing is usually performed. The cleaning conditions are not particularly limited as long as the conditions are sufficient to remove such ionic impurities. Examples of the cleaning liquid include a method of cleaning with water or an organic solvent, and cleaning with water can be exemplified as a preferable method in terms of obtaining PAS easily and inexpensively. As the kind of water to be used, ion exchange water and distilled water are preferably used.

  The washing temperature for washing the PAS is preferably 50 ° C. or more and 200 ° C. or less, more preferably 150 ° C. or more and 200 ° C. or less, and further preferably 180 ° C. or more and 200 ° C. or less. The treatment operation with a liquid of 100 ° C. or higher is usually performed by charging a predetermined amount of PAS with a predetermined amount of liquid, and heating and stirring at normal pressure or in a pressure vessel. The cleaning may be performed a plurality of times, and the cleaning temperature may be different for each cleaning. However, in order to obtain a PAS with a small amount of ionic impurities, the cleaning is performed at least once at a temperature of 150 ° C. or more, preferably twice or more. More preferably, a filtration step for separating the polymer and the washing liquid is performed between each washing.

  In the present invention, a cleaning additive may be used at the time of cleaning, and examples of the cleaning additive include acids, alkali metal salts, and alkaline earth metal salts. When using an acid, it is preferable that PAS is immersed in the aqueous solution which was made acidic by adding an organic acid or an inorganic acid to the water, and the pH of the aqueous solution after heating and washing is 2 to 8. Examples of the organic acid and the inorganic acid include acetic acid, propionic acid, hydrochloric acid, sulfuric acid, phosphoric acid, formic acid and the like, but are not limited thereto, but acetic acid and hydrochloric acid are preferable. When an alkali metal salt or an alkaline earth metal salt is used as a cleaning additive, a method of immersing PAS in an aqueous solution in which an alkali metal salt or an alkaline earth metal salt is added to the water can be exemplified. The amount of the metal salt is preferably 0.01 to 5% by weight, more preferably 0.1 to 0.7% by weight, based on PAS. Examples of the alkali metal salt and alkaline earth metal salt include, but are not limited to, the calcium salts, potassium salts, sodium salts, magnesium salts and the like of the above organic acids or inorganic acids.

  Any cleaning additive can be used as long as a PAS having excellent melt fluidity can be obtained, but when treated with an acid, higher melt fluidity is obtained, and at the same time, the obtained PAS is ashed at 550 ° C. The ash content is low and the characteristics of exhibiting excellent performance for applications requiring electrical insulation are manifested. From the viewpoint of electrical insulation, the ash content is preferably 0.5% by weight or less, and more preferably 0.3% by weight or less.

The washing additive may be used at any stage of the washing process, but in order to wash efficiently with a small amount of additive, the solid collected by the flash method is washed several times with water, Thereafter, a method of impregnating PAS in an aqueous solution to which a cleaning additive is added and treating at 150 ° C. or higher is preferable.
The ratio of the PAS and the cleaning liquid in the cleaning is preferably larger in the cleaning liquid, but usually a bath ratio of 10 to 500 g of PAS is preferably selected with respect to 1 liter of the cleaning liquid, and more preferably 50 to 200 g.

  The PAS thus obtained is dried under normal pressure and / or under reduced pressure. The drying temperature is preferably in the range of 120 to 280 ° C, more preferably in the range of 140 to 250 ° C. The drying atmosphere may be an inert atmosphere such as nitrogen, helium or reduced pressure, an oxidizing atmosphere such as oxygen or air, or a mixed atmosphere of air and nitrogen, but an inert atmosphere is preferred from the viewpoint of melt viscosity. The drying time is preferably 0.5 to 50 hours, preferably 1 to 30 hours, and more preferably 1 to 20 hours.

(10) Generated PAS
According to the method of the present invention, PAS having a small amount of volatile components can be obtained in a short time and with a high yield.

  When recovered by the quench method in the method of the present invention, the melt flow rate (measured at a temperature of 315.5 ° C. and a load of 5000 g according to ASTM D-1238-70) is 1000 g / 10 min or less, more preferably 800 g / 10 min. The following PAS with a small amount of volatile components can be obtained in good yield in a short time. Furthermore, the melt flow rate obtained by the method of the present invention (measured at a temperature of 315.5 ° C. and a load of 5000 g according to ASTM D-1238-70) is 200 g / 10 min or less, more preferably 150 g / 10 min or less. PAS with excellent melt stability and a small amount of volatile components has a high molecular weight in a linear form. Therefore, not only injection molded products but also extruded products such as sheets, films, fibers and pipes by extrusion. Can be molded.

  Moreover, the nitrogen content of the PAS obtained in the present invention tends to decrease. In general, PAS obtained by reacting a sulfidizing agent and a dihalogenated aromatic compound in the presence of an alkali metal hydroxide in an organic polar solvent contains nitrogen. This is because an alkali metal alkylaminoalkylcarboxylate produced by the reaction of an organic polar solvent such as NMP and an alkali metal hydroxide reacts with the PAS end as a side reaction during polymerization to form an end having a nitrogen atom. However, in the present invention, since the side reaction can be suppressed by performing polymerization under specific polymerization conditions, the nitrogen content tends to decrease naturally. However, if the nitrogen content is extremely low, there arises a problem that the reactivity with various coupling agents often used during melt extrusion is reduced in order to increase the toughness and strength of PAS. Therefore, the nitrogen content of PAS is preferably from 300 ppm to 1200 ppm, more preferably from 400 ppm to 1100 ppm.

  In addition, the amount of volatile components of the PAS obtained in the present invention tends to decrease. Since such volatile components cause mold contamination and mold vent clogging, which causes a problem that production efficiency deteriorates, it is preferable that the volatile component is small. In the present invention, the side reaction can be suppressed by carrying out the polymerization under specific polymerization conditions, so that the amount of volatile components also tends to decrease.

  The amount of the volatile component means the amount of the adhesive component that has been cooled and liquefied or solidified when the PAS is heated and melted under vacuum, and is a glass ampule in which PAS is sealed in a vacuum. Is measured by heating in a tubular furnace. As the shape of the glass ampule, the abdomen is 100 mm × 25 mm, the neck is 255 mm × 12 mm, and the wall thickness is 1 mm. As a specific measurement method, only the barrel of a glass ampoule in which PAS is vacuum-sealed is inserted into a 320 ° C. tubular furnace and heated for 2 hours, so that the volatile gas is generated at the neck of the ampoule not heated by the tubular furnace. Is cooled and adheres. After the neck is cut out and weighed, the attached volatile components are dissolved in chloroform and removed. The neck is then dried and weighed again. The amount of volatile components is determined from the weight difference between the ampoule necks before and after removing the volatile components.

  The PAS obtained by the method of the present invention can be used alone, but various inorganic fillers, fibrous fillers, various synthetic resins, and the like may be blended and used as desired.

(11) Other post-treatments The PAS obtained in the present invention may be treated at a temperature of 130 to 260 ° C. in an oxygen-containing atmosphere in order to remove volatile components or to increase the cross-linking molecular weight. Is possible.

  When carrying out dry heat treatment for the purpose of suppressing cross-linking high molecular weight and removing volatile matter, the temperature is preferably from 130 to 250 ° C, more preferably from 160 to 250 ° C. Further, it is desirable that the oxygen concentration is less than 2% by volume, more preferably less than 1% by volume. Drying under reduced pressure is also a preferred method. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and still more preferably 1 to 10 hours.

  When the dry heat treatment is performed for the purpose of increasing the cross-linking molecular weight, the temperature is preferably 160 to 260 ° C, more preferably 170 to 250 ° C. Further, it is desirable that the oxygen concentration is 2% by volume or more, more preferably 8% by volume or more. The treatment time is preferably 1 to 100 hours, more preferably 2 to 50 hours, and even more preferably 3 to 25 hours.

  The heat treatment apparatus may be a normal hot air dryer or a heating apparatus with a rotary blade or a stirring blade. However, for efficient and more uniform treatment, a heating device with a rotary blade or a stirring blade is used. Is more preferable.

  In developing the PAS obtained by the present invention into various uses described later, the design is an important factor. In order to provide high designability, the PAS should have a high whiteness, and the L value indicating the high whiteness is preferably 80 or more, more preferably 83 or more. Usually, when heat treatment is performed in the post-treatment of PAS, there is a tendency to color due to heat history or oxidative crosslinking. Therefore, when post-treatment is performed, it is preferably performed within a range in which such whiteness can be maintained.

(12) Applications The PAS obtained by the present invention is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is used not only for injection molding, injection compression molding and blow molding, but also for extrusion molding. Can be formed into extruded products such as sheets, films, fibers and pipes, but the PAS with a small amount of volatile components obtained in the present invention is particularly suitably applied to injection molding applications. As its injection molding applications, for example, sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed boards, Electrical and electronic parts such as tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts; VTR parts , TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts Home, office electrical product parts represented by word processor parts, etc .; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, motor parts, lighters, typewriters, etc. Machine-related parts: Optical instruments such as microscopes, binoculars, cameras, watches, precision machine-related parts; water taps, mixing faucets, pump parts, pipe joints, water flow control valves, relief valves, hot water temperature sensors, water flow Water-related parts such as sensors and water meter housings; valve alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, various valves such as exhaust gas valves, fuel-related / exhaust / intake system pipes, air intake nozzles snorkel For intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, for air conditioner Thermostat base, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, distributor, starter switch, starter relay, transmission wire harness, window washer nozzle, air conditioner panel switch Board, fuel-related electromagnetic valve coil, fuse connector, horn -Insulator, electrical component insulation plate, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition device case, vehicle speed sensor, cable liner, engine control unit case, engine driver unit case, Examples include condenser cases, motor insulating materials, automobile / vehicle-related parts such as hybrid car control system parts cases, and other various uses.

  Among the PASs obtained by the present invention, a volatile component excellent in melt stability having a melt flow rate (measured at a temperature of 315.5 ° C. and a load of 5000 g according to ASTM D-1238-70) of 200 g / 10 min or less. A small amount of PAS is particularly suitable for extrusion applications. As a method for producing a PAS film using the PAS obtained according to the present invention, a known melt film-forming method can be employed. For example, after melting PAS in a single or twin screw extruder, More by a method of making a film by cooling on an extrusion cooling drum, or by a biaxial stretching method in which the film thus produced is stretched longitudinally and laterally by a roller-type longitudinal stretching apparatus and a transverse stretching apparatus called a tenter. Although it can manufacture, it is not specifically limited to this.

  The PAS film obtained in this way has excellent mechanical properties, electrical properties, and heat resistance, and is suitably used for various applications such as dielectric films for film capacitors and chip capacitors, and films for mold release. can do.

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

  The PAS monofilament or short fiber thus obtained can be suitably used for various applications such as a papermaking dryer campus, a net conveyor, and a bag filter.

  The PAS obtained by the method of the present invention can be used alone, but various inorganic fillers, fibrous fillers, various synthetic resins, and the like may be blended and used as desired.

  Hereinafter, the method of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, the measuring method of various physical properties is as follows.

[Polymer yield]
Based on the weight (theoretical amount) assumed that all sodium sulfide in the autoclave before the polymerization step 1 was converted to PAS. When sodium sulfide is charged in excess of the dihalogenated aromatic compound, it may not be possible to convert all of it into PAS, but even in that case, the amount of sodium sulfide should be considered as a standard.

[Melt flow rate (MFR)]
According to ASTM D-1238-70, the temperature was 315.5 ° C. and the load was 5000 g. Using a Toyo Seiki melt indexer (length 8.00 mm, hole diameter 2.095 mm orifice, sample amount 7 g, preheating time 5 minutes from sample preparation to measurement start, load 5000 g) under the condition of 315.5 ° C. Measurements were made and the polymer melt flow rates were compared.

[Melt viscosity]
A capilograph 1C manufactured by Toyo Seiki Co., Ltd. was used, and a die having a hole length of 10.00 mm and a hole diameter of 0.50 mm was used. About 20 g of the sample was put into a cylinder set at 300 ° C. and held for 5 minutes, and then the melt viscosity was measured at a shear rate of 1216 sec ⁻¹ .

[Volatile component ratio]
A sample 3 g was weighed into a glass ampoule having an abdomen of 100 mm × 25 mm, a neck of 255 mm × 12 mm, and a wall thickness of 1 mm, and then vacuum-sealed. Only the barrel of this glass ampoule was inserted into a ceramic electric tubular furnace ARF-30K manufactured by Asahi Rika Seisakusho and heated at 320 ° C. for 2 hours. After the ampoule was taken out, the ampoule neck which was not heated by the tubular furnace and was attached with volatile gas was cut out with a file and weighed. Next, the adhering gas was dissolved and removed with 5 g of chloroform, dried for 1 hour in a glass dryer at 60 ° C., and then weighed again. The difference in weight of the ampoule neck before and after removing the gas was calculated, and the ratio with the amount of sample charged was defined as the volatile component ratio (% by weight).

[Melting stability]
Using a Toyo Seiki melt indexer (length 8.00 mm, hole diameter 2.095 mm orifice, sample amount 7 g, preheating time 30 minutes from sample preparation to measurement start, load 5000 g) at 315.5 ° C. Measurements were made and the retention rates (MFR 5 minutes / MFR 30 minutes) relative to the melt flow rate at a preheat time of 5 minutes were compared.

[Surface appearance]
The polymer was supplied to a 40 mmφ single screw extruder equipped with a T die, and the cylinder temperature and the die temperature were set to 310 ° C., and the take-up roll temperature was set to 150 ° C. to be extruded into a sheet shape. The sheet thickness was adjusted by the discharge amount of the extruder and the rotation speed of the take-up roll. The surface state of the obtained thermoplastic resin extruded product was visually observed and evaluated by touch. The state was evaluated in four stages as follows.
4: The surface is smooth and glossy.
3: Although there is a part where the surface is not smooth in the touch feeling, it is not visually recognized.
2: There is a portion where the surface is not smooth in the touch feeling, and a slight roughness of the surface state is confirmed visually.
1: Irregularities on the surface are confirmed both by touch and by visual observation.

[Example 1]
<Pre-process> In a 70 liter autoclave equipped with a stirrer, 4.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, N-methyl-2 -Pyrrolidone (NMP) 11.45 kg (115.50 mol), sodium acetate 2.58 kg (31.50 mol) and ion-exchanged water 5.5 kg were charged over about 3 hours to 240 ° C. while passing nitrogen at normal pressure. The mixture was gradually heated, and at the point when 9.84 kg of water and 0.28 kg of NMP were distilled out, the heating was finished and cooling was started. The residual water content in the system per mole of the alkali metal hydrosulfide charged at this time was 1.01 moles including the water consumed for the hydrolysis of NMP. Moreover, since the amount of hydrogen sulfide scattered was 1.4 mol, the sulfiding agent in the system after this dehydration step was 68.6 mol. As the hydrogen sulfide is scattered, 1.4 mol of sodium hydroxide is newly generated in the system.

  Thereafter, the mixture was cooled to 200 ° C., 10.19 kg (69.29 mol) of p-dichlorobenzene (p-DCB) and 9.37 kg (94.50 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. Step 1 and Step 2 were carried out under the following reaction conditions with stirring.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After 154 minutes of reaction at a constant temperature of 238 ° C., the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min over 9 minutes. The polymerization time in Step 1 was 214 minutes for (T1) and 176 minutes for (T1a). The reaction product was sampled at the end of Step 1, and the amount of p-DCB remaining in the sample was quantified with a gas chromatograph. The consumption rate of p-DCB, that is, the conversion rate, was calculated to be 96%.

  <Step 2> Continuing from Step 1, the temperature was raised from 245 ° C. to 270 ° C. at 0.8 ° C./min over 31 minutes, and at the same time as 270 ° C. was reached, 2.59 kg of water (144.0 mol) was added over 15 minutes. Was injected into the system. As a result, the system temperature decreased to 250 ° C. The water content in the system was 3.1 moles per mole of alkali metal hydrosulfide charged, including the water by-produced in the polymerization step. The solution was cooled to 200 ° C. at a rate of 1.0 ° C./min, and then rapidly cooled to near room temperature. The polymerization time (T2) in Step 2 was 51 minutes.

  <Polymer recovery> The content was diluted with about 35 liters of NMP, stirred as a slurry at 85 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh (aperture 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The obtained solid was diluted with 70 liters of ion-exchanged water, stirred at 70 ° C. for 30 minutes, and then filtered through an 80 mesh wire net to collect the solid several times. The solid material thus obtained was dried at 120 ° C. under a nitrogen stream to obtain dry PPS.

  The resulting PPS had a melt flow rate of 97 g / 10 min and a yield of 92.3%. The melt stability (MFR 5 minutes / MFR 30 minutes) was 0.79, and the volatile component ratio was 0.25%. The surface appearance of the 0.5 mm thick extruded sheet was level 4 (the surface was smooth and glossy).

[Example 2]
In Step 2, the temperature was raised from 245 ° C. to 255 ° C. over 12 minutes at 0.8 ° C./min. Upon reaching 255 ° C., 2.59 kg (144.0 mol) of water was injected into the system over 15 minutes. Otherwise, the polymerization and recovery steps were performed in the same manner as in Example 1. In addition, the system temperature after the water addition in the step 2 decreased to 250 ° C., and the polymerization time (T2) in the step 2 was 32 minutes.

  The obtained PPS had a melt flow rate of 140 g / 10 min and a yield of 90.5%. The melt stability (MFR 5 minutes / MFR 30 minutes) was 0.68, and the volatile component ratio was 0.25%. The surface appearance of the 0.5 mm thick extruded sheet was level 1 (surface irregularities were confirmed both by touch and by visual observation).

[Example 3]
The pre-process was performed in the same manner as in Example 1.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After 171 minutes of reaction at a constant temperature of 238 ° C., the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min over 9 minutes. The polymerization time in step 1 was 231 minutes for (T1) and 193 minutes for (T1a).

  <Step 2> Subsequent to Step 1, the temperature is raised from 245 ° C. to 255 ° C. at 0.8 ° C./min over 13 minutes, and 1.85 kg (102.9 mol) of water while maintaining the system temperature at 255 ° C. Was injected into the system over 15 minutes. The water content in the system was 2.5 moles per mole of alkali metal hydrosulfide charged, including the water by-produced in the polymerization step. After maintaining at 255 ° C. for 54 minutes, it was cooled to 200 ° C. at a rate of 1.0 ° C./minute, and then rapidly cooled to near room temperature. The polymerization time (T2) in Step 2 was 77 minutes. The polymer recovery step was performed in the same manner as in Example 1.

  The melt flow rate of the obtained PPS was 91 g / 10 min, and the yield was 91.2%. The melt stability (MFR 5 minutes / MFR 30 minutes) was 0.77, and the volatile component ratio was 0.24%. The surface appearance of the 0.5 mm thick extruded sheet was level 4 (the surface was smooth and glossy).

[Example 4]
The polymerization and recovery steps were performed in the same manner as in Example 3 except that the constant temperature state at 238 ° C. in Step 1 was 130 minutes. The polymerization time in Step 1 was 190 minutes for (T1) and 152 minutes for (T1a).

  The resulting PPS had a melt flow rate of 124 g / 10 min and a yield of 88.8%. The melt stability (MFR 5 minutes / MFR 30 minutes) was 0.79, and the volatile component ratio was 0.22%.

[Comparative Example 1]
In Step 2, the polymerization and recovery steps were performed in the same manner as in Example 1 except that water was not added when 270 ° C. was reached and water was added after holding at 270 ° C. for 100 minutes. The polymerization time (T2) in Step 2 was 151 minutes.

  The obtained PPS had a melt flow rate of 48 g / 10 min and a yield of 88.1%. The volatile component ratio was 0.30%. The surface appearance of the 0.5 mm thick extruded sheet was Level 2 (the surface was not smooth when touched, and the surface condition was slightly observed visually). These results are summarized in the table.

  From these results, it is understood that the volatile components can be reduced by setting the polymerization times T1, T1a, and T2 in step 1 and step 2 within a predetermined range. Moreover, it turns out that it is excellent in melt stability and the surface external appearance of an extrusion molded article can be improved by making superposition | polymerization time in the process 2 into 40 minutes-2 hours.

[Example 5]
<Pre-process> In a 70 liter autoclave equipped with a stirrer, 4.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.94 mol) of 96% sodium hydroxide, N-methyl-2 -Pyrrolidone (NMP) 11.45 kg (115.50 mol), sodium acetate 0.98 kg (11.90 mol) and ion-exchanged water 5.5 kg were charged, and nitrogen was passed at normal pressure to 240 ° C. over about 3 hours. The mixture was gradually heated, and at the point when 9.84 kg of water and 0.28 kg of NMP were distilled out, the heating was finished and cooling was started. The residual water content in the system per mole of the alkali metal hydrosulfide charged at this time was 1.01 moles including the water consumed for the hydrolysis of NMP. Moreover, since the amount of hydrogen sulfide scattered was 1.4 mol, the sulfiding agent in the system after this dehydration step was 68.6 mol. As the hydrogen sulfide is scattered, 1.4 mol of sodium hydroxide is newly generated in the system.

  Thereafter, the mixture was cooled to 200 ° C., 10.29 kg (69.97 mol) of p-dichlorobenzene (p-DCB) and 9.37 kg (94.50 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. Step 1 and Step 2 were carried out under the following reaction conditions with stirring.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After performing the reaction for 130 minutes at a constant temperature of 238 ° C., the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min for 9 minutes. The polymerization time in Step 1 was 190 minutes for (T1) and 152 minutes for (T1a). The reaction product was sampled at the end of Step 1, and the amount of p-DCB remaining in the sample was quantified with a gas chromatograph. The consumption rate of p-DCB, that is, the conversion rate, was calculated to be 96%.

  <Step 2> Continuing from Step 1, the temperature was raised from 245 ° C. to 255 ° C. at 0.8 ° C./min over 13 minutes, and at the same time as reaching 255 ° C., 2.59 kg (144.0 mol) of water was taken over 15 minutes. Was injected into the system. As a result, the system temperature decreased to 250 ° C. The water content in the system was 3.1 moles per mole of alkali metal hydrosulfide charged, including the water by-produced in the polymerization step. Subsequently, the temperature was lowered from 250 ° C. to 220 ° C. over 75 minutes at a temperature drop rate of 0.4 ° C./minute, and then rapidly cooled to near room temperature. The polymerization time (T2) in Step 2 was 40 minutes.

  <Polymer recovery> The content was diluted with about 35 liters of NMP, stirred as a slurry at 85 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh (aperture 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The obtained solid was diluted with 70 liters of ion-exchanged water, stirred at 70 ° C. for 30 minutes, and then filtered through an 80 mesh wire net to collect the solids three times. The obtained solid and 32 g of acetic acid were diluted with 70 liters of ion exchange water, stirred at 70 ° C. for 30 minutes, filtered through an 80 mesh wire mesh, and further obtained solids were diluted with 70 liters of ion exchange water. The mixture was stirred at 70 ° C. for 30 minutes and then filtered through an 80 mesh wire net to collect a solid. The solid material thus obtained was dried at 120 ° C. under a nitrogen stream to obtain dry PPS.

  The melt flow rate of the obtained PPS was 526 g / 10 min. The melt stability (MFR 5 minutes / MFR 30 minutes) was 0.78, and the volatile component ratio was 0.24%.

[Comparative Example 2]
The pre-process was performed in the same manner as in Example 5.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After performing the reaction at a constant temperature of 238 ° C. for 34 minutes, the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min for 9 minutes. The polymerization time in Step 1 was 94 minutes for (T1) and 56 minutes for (T1a).

  <Step 2> Subsequent to Step 1, the temperature was raised from 245 ° C. to 270 ° C. at 0.8 ° C./min for 31 minutes, and kept at a constant temperature of 270 ° C. for 70 minutes. After holding for 70 minutes, 2.59 kg (144.0 mol) of water was injected into the system over 15 minutes. As a result, the system temperature decreased to 250 ° C. The water content in the system was 3.1 moles per mole of alkali metal hydrosulfide charged, including the water by-produced in the polymerization step. Subsequently, the temperature was lowered from 250 ° C. to 220 ° C. over 75 minutes at a temperature drop rate of 0.4 ° C./minute, and then rapidly cooled to near room temperature. The polymerization time (T2) in Step 2 was 129 minutes. The polymer recovery step was performed in the same manner as in Example 5.

  The melt flow rate of the obtained PPS was 580 g / 10 min. The melt stability (MFR5 minutes / MFR30 minutes) was 0.78, and the volatile component ratio was 0.29%.

[Example 6]
<Pre-treatment> In a 70 liter autoclave equipped with a stirrer and a bottom plug valve, 8.75 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, N -Methyl-2-pyrrolidone (NMP) 11.45 kg (115.50 mol), sodium acetate 1.89 kg (23.10 mol) and ion-exchanged water 5.50 kg were charged up to 225 ° C. while passing nitrogen at normal pressure. The mixture was gradually heated over about 3 hours. When 9.84 kg of water and 0.30 kg of NMP were distilled off, the heating was finished and cooling was started. Moreover, since the amount of hydrogen sulfide scattered was 1.4 mol, the sulfiding agent in the system after this dehydration step was 68.6 mol. As the hydrogen sulfide is scattered, 1.4 mol of sodium hydroxide is newly generated in the system.

  Thereafter, the mixture was cooled to 200 ° C., 10.39 kg (70.66 mol) of p-dichlorobenzene (p-DCB) and 9.37 kg (94.50 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. Step 1 and Step 2 were carried out under the following reaction conditions with stirring.

<Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After 81 minutes of reaction at a constant temperature of 238 ° C., the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min for 9 minutes. The polymerization time in step 1 was 141 minutes for (T1) and 103 minutes for (T1a).
<Step 2> Subsequent to Step 1, the temperature was raised from 245 ° C. to 255 ° C. at 0.8 ° C./min over 13 minutes, and then reacted at a constant temperature of 255 ° C. for 30 minutes. T2 was 43 minutes.

  Immediately after step 2, the bottom valve of the autoclave is opened and the contents are flushed to the apparatus with a stirrer. The mixture was dried for 1.5 hours to recover a solid containing PPS and salts.

  The obtained recovered product and 74 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 75 ° C. for 15 minutes, and then filtered through a filter to obtain a cake. The obtained cake was washed with ion exchanged water at 75 ° C. for 15 minutes and filtered three times, and then 74 liters of cake and ion exchanged water and 0.4 kg of acetic acid were placed in an autoclave equipped with a stirrer, and the inside of the autoclave was filled with nitrogen. After the replacement, the temperature was raised to 195 ° C. Thereafter, the autoclave was cooled and the contents were taken out. The contents were filtered through a filter to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS.

The melt viscosity (measured at a temperature of 300 ° C. and a shear rate of 1216 sec ⁻¹ ) of the obtained PPS was 10 Pa · s. The volatile component ratio was 0.51%.

[Comparative Example 3]
The pre-process was performed in the same manner as in Example 6.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 245 ° C. was raised at 0.6 ° C./min over 25 minutes. The polymerization time in step 1 was 63 minutes for (T1) and 25 minutes for (T1a).

  <Step 2> Subsequent to Step 1, the temperature was raised from 245 ° C. to 270 ° C. at 0.6 ° C./min over 42 minutes, and kept at a constant temperature of 270 ° C. for 80 minutes. The polymerization time (T2) in Step 2 was 122 minutes. The polymer recovery step was performed in the same manner as in Example 6.

The melt viscosity (measured at a temperature of 300 ° C. and a shear rate of 1216 sec ⁻¹ ) of the obtained PPS was 50 Pa · s. The volatile component ratio was 0.63%.

  From these results, it can be seen that by setting the polymerization times T1, T1a, and T2 in step 1 and step 2 within a predetermined range, the volatile components can be reduced also in the PPS that has been flash-recovered.

[Comparative Example 4]
The pre-process was performed in the same manner as in Example 6 except that sodium acetate was not used.

  <Step 1> The temperature was raised from 200 ° C. to 230 ° C. at 0.8 ° C./min over 38 minutes, and subsequently from 230 ° C. to 238 ° C. was raised at 0.6 ° C./min over 13 minutes. After performing the reaction for 108 minutes at a constant temperature of 238 ° C., the temperature was raised from 238 ° C. to 245 ° C. at 0.8 ° C./min for 9 minutes. The polymerization time in Step 1 was 168 minutes for (T1) and 130 minutes for (T1a).

  <Step 2> Subsequent to Step 1, the temperature was raised from 245 ° C. to 255 ° C. over 12 minutes at 0.8 ° C./min, and then reacted at a constant temperature of 255 ° C. for 60 minutes. T2 was 72 minutes. The polymer recovery step was performed in the same manner as in Example 6.

The melt viscosity (measured at a temperature of 300 ° C. and a shear rate of 1216 sec ⁻¹ ) of the obtained PPS was 10 Pa · s. The volatile component ratio was 1.05%.

  From these results, it can be seen that even if the polymerization times T1, T1a, and T2 in step 1 and step 2 are set within a predetermined range, the volatile components cannot be reduced unless a polymerization aid is used.

Claims (11)

In a method for producing polyarylene sulfide in which an sulfidizing agent and a dihalogenated aromatic compound are reacted in an organic polar solvent in a temperature range of 200 ° C. or higher and lower than 280 ° C. in the presence of a polymerization aid, at least the following Step 1 and 2. A process for producing polyarylene sulfide, which comprises performing step 2.
Step 1: When reacting a sulfidizing agent and a dihalogenated aromatic compound in the presence of a polymerization aid in an organic polar solvent, a polymerization time including a temperature increase / decrease time within a temperature range of 200 ° C. or higher and lower than 245 ° C. (T1) is 1.5 hours or more and less than 4 hours, and in the temperature range of 230 ° C. or more and less than 245 ° C., the polymerization time (T1a) including the temperature rise / fall time is 30 minutes or more and less than 3.5 hours, A step of reacting the dihalogenated aromatic compound at the end of the step so as to have a conversion rate of 70 to 99 mol% to form a polyarylene sulfide prepolymer, and step 2: a temperature range of 245 ° C. or higher and lower than 280 ° C. In the process, the prepolymer is converted to high molecular weight polyarylene sulfide by reacting in a polymerization time (T2) including a temperature increase / decrease time of 5 minutes or more and less than 2 hours. The polymerization assistant present in the reaction system at the start of Step 1 is an organic carboxylic acid metal salt, an alkali metal chloride (excluding sodium chloride), an organic sulfonic acid metal salt, an alkali metal sulfate, an alkaline earth 2. The method for producing polyarylene sulfide according to claim 1, wherein the method is at least one compound selected from metal oxides, alkali metal phosphates and alkaline earth metal phosphates. The ratio (T1 / T2) of the polymerization time (T1) in the step 1 and the polymerization time (T2) in the step 2 is 1.2 or more, wherein the polyarylene sulfide according to claim 1 or 2 is characterized. Production method. The method for producing polyarylene sulfide according to any one of claims 1 to 3, wherein the polyarylene sulfide is recovered by a quench method. In step 2, water is added to the reaction system so that 0.8 mol or more and less than 4 mol of water is present per 1 mol of the charged sulfidizing agent, and the molar ratio of water to the polymerization aid [polymerization The amount of auxiliary agent (mol) / water content (mol)] is set to 0.05 to 0.5, and the prepolymer is converted to high molecular weight polyarylene sulfide. A process for producing arylene sulfide. 6. The dihalogenated aromatic compound present in the reaction system at the start of Step 1 is 0.9 mol or more and less than 1.5 mol with respect to 1 mol of the sulfidizing agent. A process for producing the polyarylene sulfide as described. 7. The polyarylene sulfide according to claim 1, wherein the water content in the organic polar solvent in the step 1 is 0.5 or more and less than 1.5 mol per mol of the sulfidizing agent charged. Production method. The polymerization assistant present in the reaction system at the start of the step 1 is 0.1 mol or more and less than 0.7 mol with respect to 1 mol of the sulfidizing agent. A method for producing polyarylene sulfide. 9. The alkali metal hydroxide present in the reaction system at the start of the step 1 is 0.9 mol or more and less than 1.2 mol with respect to 1 mol of the sulfidizing agent. A process for producing polyarylene sulfide. The method for producing polyarylene sulfide according to any one of claims 1 to 9, wherein the organic polar solvent used in the reaction is 2.5 mol or more and less than 5.5 mol with respect to 1 mol of the sulfidizing agent. An extruded product obtained by extruding the polyarylene sulfide obtained by the production method according to claim 1.