JP2015143321A - Method of producing polyarylene sulfide, and polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain a polyarylene sulfide having high melt viscosity and excellent spinnability without increasing its molecular weight.SOLUTION: A polyarylene sulfide with carboxylate content of more than 100 μmol/g and less than 400 μmol/g has an organic acid metal salt or inorganic acid metal salt in a molar ratio 0.1-5 relative to the carboxylate content added thereto for cleaning, so that a polyarylene sulfide having high melt viscosity is obtained.

Description

  The present invention relates to a method for easily preparing a polyarylene sulfide having a high melt viscosity suitable for extrusion molding without increasing the molecular weight, and a polyarylene sulfide excellent in spinnability.

Polyarylene sulfide (hereinafter abbreviated as PAS) typified by polyphenylene sulfide (hereinafter abbreviated as PPS) has properties suitable as engineering plastics such as excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties, and heat and moisture resistance. It is used for various electrical / electronic parts, machine parts, automobile parts, films, fibers, etc. mainly for injection molding and extrusion molding. In particular, when PAS is used for extrusion molding applications such as films and fibers, a highly viscous PAS is required, and various methods as described below have been proposed in order to obtain the PAS. For example, in Patent Document 1, in order to obtain a high melt viscosity PAS that can be applied to a molding process of a film, sheet, fiber, or the like, specifically, a PAS of 1000 poise (310 ° C., shear rate 200 sec ⁻¹ ) or more, Manufacturing methods have been proposed that control the temperature and the amount of water. In this method, PAS is made to have a high molecular weight and a high melt viscosity is expressed, and it takes a long polymerization time to increase the molecular weight, and furthermore, a large amount of water is put into a polymerization system having a boiling point of water or higher. In addition, a high-pressure reaction vessel and a high-pressure pump are required, and the manufacturing process is complicated. Patent Document 2 proposes a thermally oxidized PAS as a PAS having excellent yarn strength and melt spinnability. The PAS before heat treatment is made high in molecular weight by using sodium acetate as a polymerization aid during polymerization, and more appropriately It has undergone a process of heat treatment. When a polymerization aid is used at the time of polymerization, there is a problem that the polymerization aid needs to be post-treated after the polymerization, and the amount of residue (gelled product) when the heat-treated PAS is filtered while hot is kept low. Thus, there is a problem that complicated operations are required, such as the need to precisely control the heat treatment conditions.

JP 61-7332 A (Claims) International Publication No. 2006/059509 (Claims)

  The present invention has been achieved as a result of studying as an object to easily prepare polyarylene sulfide having a high melt viscosity suitable for extrusion molding without increasing the molecular weight.

  In the present invention, as a result of intensive studies to solve such problems, a PAS having a specific carboxylate content and a specific amount of organic acid metal salt or inorganic acid metal salt are added and washed. The present inventors have found that a PAS having a high melt viscosity suitable for extrusion molding can be obtained without using such a high molecular weight PAS.

That is, the present invention is as follows.
1. Washing polyarylene sulfide having a carboxylate content of more than 100 μmol / g and less than 400 μmol / g by adding an organic acid metal salt or an inorganic acid metal salt in a molar ratio to the carboxylate content of 0.1 to 5. A process for producing polyarylene sulfide characterized by the above.
2. Sulfiding agent, alkali metal hydroxide, dihalogenated aromatic compound, and halogenated aromatic carboxylic acid compound or halogenated aromatic carboxylate in an organic polar solvent in a temperature range of 200 ° C. or higher and lower than 280 ° C. 2. The method for producing polyarylene sulfide according to 1, wherein the reaction is carried out using a compound, and the resulting polyarylene sulfide is washed.
3. 3. Production of polyarylene sulfide according to 2, wherein a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound is reacted in an amount of 0.01 mol or more and less than 10 mol with respect to 100 mol of the sulfidizing agent. Method.
4). 3. The method for producing polyarylene sulfide according to 2, wherein a polyarylene sulfide is obtained by reacting a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound with 2 mol or more and less than 8 mol with respect to 100 mol of the sulfidizing agent.
5. The method for producing polyarylene sulfide according to any one of 1 to 4, wherein the organic acid metal salt or inorganic acid metal salt is an alkaline earth metal salt.
6). The ratio (B / A) of the melt viscosity (A) of the polyarylene sulfide before washing and the melt viscosity (B) of the polyarylene sulfide resin after washing is from 2.5 to 10. A method for producing a polyarylene sulfide according to any one of the above.
7). A polyarylene sulfide having a carboxylate content of more than 100 μmol / g and less than 400 μmol / g and a metal content of more than 40 μmol / g and less than 400 μmol / g.
8). 8. The polyarylene sulfide according to 7, wherein the metal content with respect to the carboxylate content is 0.4 or more and less than 4 in molar ratio.

  According to the present invention, a polyarylene sulfide having a high melt viscosity and excellent spinnability can be easily obtained.

  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 (K), among which the formula (A) is particularly preferable.

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, a halogen group, and a carboxy 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 (L) to (N). The amount of copolymerization of these branched units or cross-linked units is preferably in the range of 0 to 1 mol% with respect to 1 mol of-(Ar-S)-units.

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

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

Is a polyphenylene sulfide containing 80 mol% or more. Moreover, the unit of benzoic acid and its salt may be contained in the main chain skeleton of PAS in an amount of 1 to 20 mol% or more, preferably 1 to 10 mol% or more.

  For the PAS of the present invention, a sulfidizing agent, an organic polar solvent, a dihalogenated aromatic compound, a halogenated aromatic carboxylic acid compound, a polymerization aid, a molecular weight modifier, a polymerization stabilizer, a dehydration step, a polymerization step, a polymer used for polymerization Description will be made in the order of recovery, metal salt cleaning, and PAS after metal salt cleaning.

(1) Sulfiding agent The sulfiding agent used in the production of PAS includes alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfides. Alkali metal sulfides are easy to handle and versatile. , Alkali metal hydrosulfides, and mixtures thereof are preferably used. The sulfiding agent can be used as a hydrate or aqueous mixture or in the form of an anhydride. A sulfidizing agent prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used.

  Preferred sulfiding agents include sodium sulfide and sodium hydrosulfide, and it is preferably used in the form of an aqueous mixture from the viewpoint of handleability.

  The amount of the sulfiding agent used means that the residual amount obtained by subtracting the loss from the actual charge when there is a partial loss of the sulfiding agent before the start of the polymerization reaction due to the dehydration operation described below. To do.

  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 90 mol or more and less than 120 mol with respect to 100 mol of the alkali metal hydrosulfide, The range is preferably 95 mol or more and less than 115 mol, more preferably 95 mol or more and less than 110 mol. 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 When producing PAS, an organic polar solvent is usually 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, From the viewpoint of the stable reactivity and economical efficiency, it is 250 mol or more and less than 550 mol per 100 mol of sulfidizing agents, Preferably it is 250 mol or more and 500 mol. The range of less than, more preferably 250 mol or more and less than 450 mol is selected.

(3) Dihalogenated aromatic compound When producing the PAS of the present invention, a dihalogenated aromatic compound is used. When producing PPS, which is representative of PAS, the benzene ring and sulfur become the main skeleton of the polymer. Therefore, the dihalogenated aromatic compounds used include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, p- And dihalogenated benzenes such as dibromobenzene. In addition, for the purpose of introducing carboxylate, 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 2,6-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, etc. as halogenated aromatic carboxylic acid compounds It is also a preferred embodiment to use a dihalogenated aromatic carboxylic acid compound or a salt thereof as a copolymerization monomer. Furthermore, unless the effects of the present invention are impaired, 2,4-dichloroaniline, 2,5-dichloroaniline, 2,6-dichloroaniline, 3,5-dichloroaniline, 2,4-dichlorophenol, 2,5- Dichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol, 1-methoxy-2,5-dichlorobenzene, 4,4'-dichlorophenyl ether, 4,4'-dichlorodiphenyl sulfoxide, 4,4'- It is also possible to use dihalogenated aromatic compounds such as dichlorophenyl ketone. Of these, p-dihalogenated benzene typified by p-dichlorobenzene is preferred as the main component, and dihalogenated benzoic acid typified by 2,4-dichlorobenzoic acid and 2,5-dichlorobenzoic acid or the like. Part of the use of a salt as a copolymerization component is also a preferred embodiment for increasing the carboxylate content of PAS.

  The amount of the dihalogenated aromatic compound used in the present invention is 80 mol or more and less than 150 mol, preferably 90 mol or more per 100 mol of the sulfidizing agent, from the viewpoint of efficiently suppressing the decomposition and reducing the viscosity of the PAS suitable for processing. The range is less than 110 moles, more preferably 95 moles or more and less than 105 moles. When the amount is less than 80 moles per 100 moles of the sulfidizing agent, decomposition tends to occur. When a dihalogenated aromatic carboxylic acid compound or a salt thereof is used as a copolymerization component, the amount of the dihalogenated aromatic carboxylic acid compound or a salt thereof used in the total amount of the dihalogenated aromatic compound is 100 mol of the sulfidizing agent. A range of 0.1 mol or more and less than 20 mol, preferably 1 mol or more and less than 15 mol, more preferably 2 mol or more and less than 10 mol can be exemplified. When the amount is less than 0.1 mol per 100 mol of the sulfidizing agent, the effect of the present invention cannot be obtained because the carboxylate content of the obtained PAS is small, and when it is 20 mol or more, the molecular weight decreases and the mechanical properties are reduced. There is a tendency not to develop.

  When a dihalogenated aromatic carboxylic acid compound or a salt thereof is used, there is no particular limitation on the addition timing, and it may be added at any time during the dehydration step, the start of polymerization, or during the polymerization described later, or multiple times. It may be added separately.

(4) Halogenated aromatic carboxylic acid compound When the PAS of the present invention is produced, a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound is added for the purpose of obtaining a PAS having a high carboxylate content. Is also one of the preferred embodiments. Specifically, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-chlorobenzoic acid, sodium 4-chlorophthalate, 2-amino-4-chlorobenzoic acid, 4-chloro-3-nitrobenzoic acid, Examples thereof include monohalogenated aromatic carboxylic acids such as 4′-chlorobenzophenone-2-carboxylic acid or salts thereof, and 3-chlorobenzoic acid, 4-chlorobenzoic acid, 4 from the reactivity and versatility during polymerization. -Sodium hydrogen chlorophthalate or salts thereof are preferred. Unless the effects of the present invention are impaired, chlorobenzene, 1-chloronaphthalene, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 4- Chlorobenzamide, 4-chlorobenzeneacetamide, 4-chlorobenzenesulfonamide, 4-chlorobenzenesulfonic acid, 4-chlorobenzenethiol, 2-amino-5-chlorobenzophenone, 2-amino-4-chlorophenol, 2-chloronitrobenzene, 3- Monohalogenated compounds typified by chloronitrobenzene, 4-chloronitrobenzene, 4-chlorophthalic anhydride, and the like, and mixtures thereof can also be used.

  When a halogenated aromatic carboxylic acid compound or a salt thereof is used in the present invention, the amount used is preferably 0.01 mol or more and less than 20 mol, more preferably 0.1 mol or more and 15 mol, per 100 mol of the sulfidizing agent. Less than, More preferably, it is 1.0 mol or more and less than 10 mol, Most preferably, it is the range of 2.0 mol or more and less than 8 mol. When the amount is less than 0.01 mol per 100 mol of the sulfidizing agent, the effect of the present invention cannot be obtained because the carboxylate content of the obtained PAS is small, and when it is 20 mol or more, the molecular weight decreases and the mechanical properties are reduced. There is a tendency not to develop.

  By using the halogenated aromatic carboxylic acid compound or a salt thereof in the above range, the carboxylate content of the obtained PAS can be more than 100 μmol / g and less than 400 μmol / g. The lower limit of the carboxylate content of PAS is preferably 130 μmol / g or more, more preferably 150 μmol / g or more, and particularly preferably 160 μmol / g or more. Further, the upper limit of the carboxylate content of PAS is preferably 350 μmol / g or less, more preferably 300 μmol / g or less, and even more preferably 250 μmol / g or less.

Here, the carboxylate content of PAS was determined by a calibration curve in which the carboxylate content contained in sodium benzoate was quantified at a peak of 1550 cm ⁻¹ using a Fourier transform infrared spectrometer (hereinafter abbreviated as FT-IR). decide. Specifically, it was calculated by the following method. PPS (cake) prepared in Reference Examples described later and 74 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, acetic acid was added and the atmosphere was replaced with nitrogen, and the temperature was raised to 195 ° C. Thereafter, the autoclave was cooled and the contents were taken out. The content was filtered through a filter to obtain a cake, and the pH of the filtrate was 4. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS (0). The obtained PPS was confirmed to contain no metal from the measurement of the metal content described later, that is, it was confirmed that the carboxylate was not contained.

PPS (0) and dry PPS obtained in Reference Examples and Examples to be described later were melted at 300 ° C., and the obtained press film was set in FT-IR and measured to obtain an IR spectrum. The IR spectrum of PPS (0) was subtracted from the IR spectrum of dry PPS obtained in Reference Examples and Examples to obtain a peak intensity of a carboxylate of 1550 cm ⁻¹ . Separately, IR measurement of sodium benzoate was performed, and the carboxylate content of PPS obtained in Reference Examples and Examples was calculated based on the calibration curve of carboxylate prepared from the peak intensity of 1550 cm ⁻¹ .

  The total amount of halogenated compounds such as dihalogenated aromatic compounds and halogenated aromatic carboxylic acid compounds is preferably in a specific range, and the total amount of halogenated compounds is 98 mol with respect to 100 mol of the sulfidizing agent. The amount is preferably less than 110 mol, more preferably from 100 mol to less than 108 mol, and still more preferably from 103 mol to less than 107 mol. When the total amount of the halogenated compound is less than 98 mol with respect to 100 mol of the sulfidizing agent, it tends to decompose, and when it is 110 mol or more, the molecular weight tends to decrease and mechanical properties do not tend to be expressed. The halogenated compounds include not only the above-mentioned dihalogenated aromatic compounds and halogenated aromatic carboxylic acid compounds, but also polyhalogenated compounds of trihalogenated or higher used in branching / crosslinking agents described later.

  There is no particular limitation on the timing of addition of the halogenated aromatic carboxylic acid compound or a salt thereof, and it may be added at any time during the dehydration step, at the start of polymerization, or during polymerization, which will be described later, or in multiple portions. May be. When a monohalogenated aromatic carboxylic acid compound or a salt thereof is used, it contributes not only to an increase in the carboxylate content in PAS but also to a reduction in the chlorine content.

(5) Polymerization aid When producing the PAS of the present invention, it is one of preferred embodiments to use a polymerization aid. The purpose of using the polymerization aid is to adjust the PAS to a desired melt viscosity. Specific examples of the polymerization aid include, for example, organic carboxylic acid metal salts, water, alkali metal chlorides (excluding sodium chloride), organic sulfonic acid metal salts, alkali metal sulfates, alkaline earth metal oxides, and alkalis. Examples thereof include metal phosphates and alkaline earth metal phosphates. These may be used alone or in combination of two or more. Of these, organic carboxylic acid metal salts and / or water are preferably used.

  Specific examples of organic carboxylic acid metal salts include lithium acetate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, and mixtures thereof. Sodium acetate, which is inexpensive and has moderate solubility in the reaction system, is preferably used.

  The amount used in the case of using the above organic carboxylic acid metal salt as a polymerization aid is preferably in the range of 1 mol or more and less than 70 mol, more preferably in the range of 2 mol or more and less than 60 mol, relative to 100 mol of the charged sulfidizing agent. The range of 2 mol or more and less than 55 mol is more preferable.

  When water is used as a polymerization aid, it is possible to use water alone, but it is preferable to use an organic carboxylic acid metal salt at the same time, which can further enhance the effect as a polymerization aid and reduce polymerization. There is a tendency that a PAS having a desired melt viscosity can be obtained in a short time even with the use amount of the auxiliary agent. In this case, the preferable range of the amount of water in the polymerization system is 80 to 300 mol, and more preferably 85 to 180 mol with respect to 100 mol of the sulfidizing agent.

(6) Molecular Weight Modifier When producing the PAS of the present invention, a polyhalogen having a tri- or higher halogenation is used in order to form a branched or cross-linked polymer and adjust to a desired melt viscosity without impairing the effects of the present invention. It is also possible to use a branching / crosslinking agent such as a compound in combination. A polyhalogenated aromatic compound is preferable as the polyhalogen compound, and specific examples include 1,3,5-trichlorobenzene and 1,2,4-trichlorobenzene.

(7) Polymerization stabilizer In producing the PAS of the present invention, a polymerization stabilizer can be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilization of the polymerization reaction system and suppresses undesirable side reactions such as the formation 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. The aforementioned organic carboxylic acid metal salt also acts as a polymerization stabilizer. 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 desirably used in a proportion of usually 1 to 20 mol, preferably 3 to 10 mol, per 100 mol of the sulfidizing agent in the reaction system before the start of the polymerization reaction. If this ratio is too large, it tends to be economically disadvantageous and 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. The polymerization stabilizer may be added at any time during the dehydration step described later, at the start of the polymerization, or during the polymerization, or may be added in a plurality of times.

(8) Dehydration step When the PAS of the present invention is produced, the sulfiding agent is usually used in the form of a hydrate, but before adding the dihalogenated aromatic compound or monohalogenated compound, an organic polar solvent and It is preferable to raise the temperature of the mixture containing the sulfidizing agent and remove excess water out of the system. 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. When a halogenated aromatic carboxylate is used, it is a non-volatile compound, so even if it is added at the stage of the dehydration step, it will not volatilize and can contribute to the reaction well in the subsequent polymerization step.

  The amount of water in the system at the stage when the dehydration step is completed is preferably 90 to 110 mol per 100 mol of the charged sulfidizing agent. 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 dehydration step.

(9) Polymerization Step When the PAS of the present invention is produced, a polymerization step is performed in which the reaction product prepared in the dehydration step is brought into contact with a dihalogenated aromatic compound or monohalogenated compound in an organic polar solvent to cause a polymerization reaction. At the start of the polymerization step, the sulfidizing agent and the polyhalogenated aromatic compound are added to the organic polar solvent desirably in an inert gas atmosphere at a temperature of 100 to 220 ° C., preferably 130 to 200 ° C. A polymerization aid may be added at this stage. The order in which these raw materials are charged may be out of order or may be simultaneous.

The polymerization step is performed in a temperature range of 200 ° C. or higher and lower than 280 ° C., but there is no limitation on the polymerization conditions as long as the effect of the present invention is obtained. For example, after raising the temperature at a constant rate, the reaction is continued for a certain time at 245 ° C. or more and less than 280 ° C., after reacting at a constant temperature at 200 ° C. or more and less than 245 ° C. for a certain time, the temperature rises to 245 ° C. or more and less than 280 ° C. A method in which the reaction is continued for a certain period of time by heating, followed by a reaction at a constant temperature at 200 ° C. or higher and lower than 245 ° C., particularly 230 ° C. or higher and lower than 245 ° C., and then raising the temperature to 245 ° C. or higher and lower than 280 ° C. for a short time. And a method for completing the reaction. Among them, preferable polymerization conditions for obtaining a PAS having a high carboxylate content necessary for obtaining the PAS of the present invention include a sulfidizing agent and a predetermined amount of a dihalogenated aromatic compound or a monovalent compound in an organic polar solvent. When a halogenated compound is reacted in a temperature range of 200 ° C. or higher and lower than 280 ° C. to obtain PAS,
<Step 1> Within a temperature range of 230 ° C. or more and less than 245 ° C., the polymerization time (T1a) including the temperature rising / falling time is 30 minutes or more and less than 3.5 hours, and the dihalogenated aromatic compound at the end of the step A step of producing a prepolymer of PAS by reacting such that the conversion is 70 to 98 mol%, and <Step 2> in a temperature range from 245 ° C. to less than 280 ° C. A step of reacting T2) for 5 minutes to less than 1 hour to obtain PAS;
The polymerization conditions which pass through are mentioned.

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

  <Step 1> In order to obtain a PAS having a high carboxylate content, it is preferable to carry out Step 2 after sufficiently increasing the conversion rate of the dihalogenated aromatic compound or monohalogenated compound at a low temperature. If the reaction is less than the reaction rate, the conversion rate of the dihalogenated aromatic compound or monohalogenated compound is difficult to increase, and the melt viscosity of the PAS obtained through Step 2 is too low, and the melt viscosity suitable for extrusion molding is high. It tends not to be obtained. In addition, a long reaction time is required 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, in a temperature range of 230 ° C. or higher and lower than 245 ° C. where the reaction rate is relatively high, it is 30 minutes or longer and shorter than 3.5 hours, preferably 40 minutes or longer and shorter than 3.5 hours, more preferably 1 hour or longer and shorter than 3 hours. It is preferable to carry out the reaction for 1.5 hours or more and less than 3 hours. In order to increase the conversion rate of the dihalogenated aromatic compound in a temperature range of 230 ° C. or more and less than 245 ° C., which is relatively high in reaction rate, it is preferable in terms of production efficiency to shorten the polymerization time in the temperature range of less than 230 ° C. The polymerization time in the temperature range of 200 ° C. or more and less than 230 ° C. is preferably within 2 hours, and more preferably within 1 hour. Furthermore, the polymerization time (T1) including the temperature increase / decrease time within the temperature range of 200 ° C. or more and less than 245 ° C. including Step 1 is preferably 1.5 hours or more and less than 4 hours, and 1.5 hours or more and 3 Less than 5 hours is more preferable, and 2 hours or more and 3.5 hours or less is 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 sulfiding agent causes decomposition of the prepolymer in Step 2, and the obtained PAS is heated and melted. Volatile components tend to increase. Moreover, when T1 exceeds 4 hours, it will lead to a reduction in production efficiency.

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.

It is preferable to react so that the conversion rate of the dihalogenated aromatic compound at the end of Step 1 is 70 to 98 mol% to form a PAS prepolymer, more preferably 75 mol% or more, and still more preferably 80 mol. %, More preferably 90 mol% or more. When the process proceeds to step 2 with such a low conversion rate, the unreacted sulfidizing agent causes decomposition of the prepolymer, and the amount of volatile components tends to increase when the obtained PAS is heated and melted. Further, if the reaction is carried out until the conversion rate in Step 1 exceeds 98 mol%, a long polymerization time is required, leading to a decrease in production efficiency. 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 dihalogenated aromatic compound is added excessively in a molar ratio with respect to the sulfidizing agent, conversion rate = [[DHA charge (mol) -DHA remaining amount (mol)] / [DHA charge (mol)- DHA excess (mole)]] × 100%
(B) In cases other than (a) above, conversion rate = [[DHA charge (mol) −DHA remaining amount (mol)] / [DHA charge (mol)]] × 100%.

  <Step 2> The final temperature in Step 2 is preferably 275 ° C. or lower, and more preferably 270 ° C. or lower. If the polymerization is terminated only in step 1 without passing through step 2, or the polymerization time in step 2 is extremely short, the PAS has a melt viscosity that is too low, and a PAS having a melt viscosity suitable for extrusion can be obtained. In addition, the carboxylate content of PAS is low due to the low reaction rate of halogenated aromatic carboxylic acids or salts thereof, and the effect of reducing the chlorine content is small when monohalogenated compounds are used. Further, when the flash method is used in the polymer recovery step described later, since the flash energy becomes small when the temperature of the polymer is low, there is a problem that the heat of vaporization of the polymerization solvent is reduced and the flash recovery cannot be efficiently performed. When the final temperature of step 2 reaches 280 ° C. or higher, the increase in the internal pressure of the reactor tends to increase, and a reactor having high pressure resistance may be required. It is not preferable. In addition, as the polymerization temperature increases, the carboxylate introduced into the PAS tends to be thermally decomposed or modified, and the thickening effect when the obtained PAS is washed with an organic acid metal salt or an inorganic acid metal salt decreases. , The spinnability tends to decrease.

  The polymerization time (T2) in step 2 is preferably 5 minutes or more and less than 1 hour, more preferably 10 minutes or more and less than 40 minutes, and even more preferably 10 minutes or more and less than 30 minutes. When the polymerization time (T2) in step 2 is 1 hour or longer, the amount of volatile components tends to increase when the obtained PAS is melted and heated. In addition, a long polymerization time leads to a decrease in production efficiency, and at the same time, the carboxylate introduced into the PAS is thermally decomposed or modified, and the viscosity increased when the obtained PAS is washed with an organic acid metal salt or an inorganic acid metal salt. The effect tends to decrease and the spinnability tends to decrease.

  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.

  The ratio (T1a / T2) of the polymerization time (T1a) in step 1 and the polymerization time (T2) in step 2 is preferably 0.5 or more. The higher the ratio, the more the polymerization time in Step 1 can be secured, and the conversion rate of the dihalogenated aromatic compound or monohalogenated compound can be increased. At the same time, the polymerization time in Step 2 can be suppressed to a short time. . Moreover, since the thermal decomposition and modification | denaturation of the carboxylate introduce | transduced into PAS can also be suppressed by suppressing reaction at high temperature like process 2 for a short time, the obtained PAS is organic acid metal salt or inorganic acid. When washed with a metal salt, a high thickening effect is exhibited and good spinnability is obtained. Therefore, T1a / T2 is more preferably 1 or more, more preferably 2 or more, and even more preferably 5 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 addition, it is preferable that the ratio (T1 / T2) of the polymerization time (T1) in the temperature range including Step 1 to 200 ° C. or more and less than 245 ° C. to the polymerization time (T2) in Step 2 is 1.2 or more. The higher the ratio, the more sufficient the polymerization time at a low temperature and the higher the conversion rate of the dihalogenated aromatic compound or monohalogenated compound, and at the same time the polymerization time in step 2 can be suppressed to a short time. . Therefore, T1 / T2 is more preferably 3 or more, and even more preferably 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.

  Furthermore, the total reaction time (T1 + T2) from the start of step 1 to the end of step 2 is preferably less than 5 hours, more preferably less than 4 hours, and even more preferably less than 3.5 hours. Longer polymerization time leads to lower production efficiency, and the carboxylate is thermally decomposed and denatured, and the thickening effect when the obtained PAS is washed with an organic acid metal salt or an inorganic acid metal salt is reduced. The spinnability tends to decrease.

  The atmosphere during the polymerization is preferably a non-oxidizing atmosphere, and is preferably carried out in an inert gas atmosphere such as nitrogen, helium, or argon. 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.

(10) Polymer recovery When the PAS of the present invention is produced, after the polymerization step is completed, the 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. As long as the effect of the present invention is obtained, the method is not limited to either the quench method or the flash method.

  Since the obtained PAS 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.

  In order to obtain the effect of the present invention, the melt viscosity of PAS before metal cleaning described later is preferably 2 to 100 Pa · s, more preferably 3 to 50 Pa · s, and 5 to 20 Pa · s. It is even more preferable.

Here, for the 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 .

  In the present invention, a PAS having a high melt viscosity suitable for extrusion molding can be easily prepared without using a conventional high molecular weight PAS. However, if the molecular weight of the PAS of the present invention is too low, even if the PAS has a high carboxylate content and a high melt viscosity, mechanical properties tend not to be expressed. The average molecular weight is preferably 10,000 or more and less than 100,000, more preferably 10,000 or more and less than 50,000, still more preferably 10,000 or more and less than 30,000. Here, the weight average molecular weight is a value calculated in terms of polystyrene by gel permeation chromatography.

(11) Metal Salt Cleaning In the present invention, it is necessary to add an organic acid metal salt or an inorganic acid metal salt to a PAS having a specific carboxylate content in a specific range for cleaning. In the case of PAS having a carboxylate content outside the range, sufficient effects of the present invention cannot be obtained. Examples of the organic acid and inorganic acid include acetic acid, propionic acid, hydrochloric acid, sulfuric acid, phosphoric acid, formic acid and the like, and the metal salt includes potassium salt, sodium salt, magnesium salt, calcium salt, barium salt, zinc salt, copper salt, An aluminum salt etc. can be illustrated. The PAS of the present invention is a PAS containing a high carboxylate, and a metal salt having a polyvalent cation is preferred for obtaining a PAS having a high melt viscosity more easily. Organic acid alkaline earth metal salts are preferable from the viewpoints of economy, handleability, and solubility during cleaning, and calcium acetate and magnesium acetate are more preferable cleaning additives.

  The addition amount of the organic acid metal salt or inorganic acid metal salt needs to be 0.1 to 5 in terms of molar ratio with respect to the carboxylate content contained in the polyarylene sulfide, preferably 0.2 to 3, more preferably 0.3-2. When it is less than 0.1, the thickening effect of PAS tends to decrease and the spinnability tends to decrease. Moreover, adding exceeding 5 means adding in large excess with respect to the carboxylate content of PAS, and is economically unpreferable.

  The washing temperature when washing PAS is preferably 80 ° C. or higher and 220 ° C. or lower, more preferably 150 ° C. or higher and 200 ° C. or lower, and even more preferably 180 ° C. or higher and 200 ° C. or lower in terms of obtaining PAS with less ionic impurities.

  When water is used for washing, it is preferably distilled water or deionized water, and the ratio of PAS to liquid is usually preferably selected as a bath ratio of 10 to 500 g of PAS to 1 liter of liquid.

  The organic acid metal salt or inorganic acid metal salt that is a cleaning additive may be used in any stage of the cleaning process. However, in order to efficiently perform the cleaning with a small amount of additive, the solid material is 80 ° C. or higher and 220 ° C. or higher. A method of immersing and treating PAS in an aqueous solution containing a metal salt at 150 ° C. or higher after performing a treatment of immersing and filtering several times in hot water of ≦ ° C. is preferred.

  The PAS subjected to the metal salt washing is dried under normal pressure and / or reduced pressure. The drying temperature is preferably in the range of 120 to 280 ° 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.

  In order to remove the volatile component or to adjust to a preferable melt viscosity by removing the volatile component, the obtained PAS is within a range of 130 to 260 ° C. in an oxygen-containing atmosphere as long as the effects of the present invention are not impaired. It is also possible to process at temperature for 0.1 to 20 hours.

(12) PAS after metal salt washing
The PAS subjected to metal salt washing has a carboxylate content of more than 100 μmol / g and less than 400 μmol / g, and the lower limit of the carboxylate content is preferably 130 μmol / g or more, more preferably 150 μmol / g or more. 160 μmol / g or more is particularly preferable. Further, the upper limit of the carboxylate content of PAS is preferably 350 μmol / g or less, more preferably 300 μmol / g or less, and even more preferably 250 μmol / g or less. In the present invention, the PAS having a specific carboxylate content range is washed by adding an organic acid metal salt or an inorganic acid metal salt without changing the weight average molecular weight of PAS or the degree of crosslinking. The melt viscosity can be remarkably increased, and a PAS excellent in spinnability can be obtained. When the carboxylate content of PAS is 100 μmol / g or less, the thickening effect of PAS when washing is performed by adding an organic acid metal salt or an inorganic acid metal salt is small, and improvement in spinnability cannot be expected. On the other hand, if the carboxylate content of PAS is 400 μmol / g or more, the amount of volatile components tends to increase, and the molecular weight of PAS decreases, so the fibers tend to cut during spinning.

  Washing PAS by adding an organic acid metal salt or an inorganic acid metal salt causes the metal to be incorporated into the PAS, leading to a significant improvement in melt viscosity. However, the amount of incorporated metal exceeds 40 μmol / g and 400 μmol / g. Is preferably less than 350 μmol / g, more preferably more than 60 μmol / g and less than 300 μmol / g. When the metal content of PAS is 40 μmol / g or less, the effect of thickening is not sufficient, and improvement in spinnability cannot be expected. On the other hand, if the metal content is 400 μmol / g or more, the electrical insulation properties are lowered, and it may be difficult to use for electrical and electronic applications.

  The metal content shown here was a value measured by atomic absorption by ashing the PAS after washing with the metal salt. Specifically, the metal content was measured by the following method. PAS (5 g) was precisely weighed in a platinum dish preheated to 550 ° C., and placed in an electric furnace at 550 ° C. for 24 hours for ashing. The ashed product was thermally decomposed with hydrofluoric acid, dissolved with dilute hydrochloric acid, and various metal contents were measured with an atomic absorption spectrometer Z2300 manufactured by Hitachi High-Technologies Corporation.

  The melt viscosity of PAS after metal washing is preferably 5 to 1000 Pa · s, more preferably 20 to 500 Pa · s, and still more preferably 40 to 200 Pa · s.

  In the present invention, a PAS having a specific carboxylate content is washed by adding an organic acid metal salt or an inorganic acid metal salt, and the melt viscosity is greatly increased. B / A which is the ratio of the melt viscosity (B) of the polyarylene sulfide resin after washing to the melt viscosity (A) of the arylene sulfide can be 2.5 to 10. The higher this ratio, the greater the increase in melt viscosity due to metal salt washing, but in order to exceed this ratio, a PAS containing a high carboxylate is required and a large amount of organic acid metal salt or inorganic acid metal salt is required. Must be added at the time of washing, which is economically undesirable.

  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 a physical property is as follows.

[Carboxylate content]
The carboxylate content was calculated by the following method using a Fourier transform infrared spectrometer (hereinafter abbreviated as FT-IR).

  PPS (cake) prepared in Reference Examples described later and 74 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, acetic acid was added and the atmosphere was replaced with nitrogen, and the temperature was raised to 195 ° C. Thereafter, the autoclave was cooled and the contents were taken out. The content was filtered through a filter to obtain a cake, and the pH of the filtrate was 4. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS (0). The obtained PPS was confirmed to contain no metal from the measurement of the metal content described later, that is, it was confirmed that the carboxylate was not contained.

PPS (0) and dry PPS obtained in Reference Examples and Examples to be described later were melted at 300 ° C., and the obtained press film was set in FT-IR and measured to obtain an IR spectrum. The IR spectrum of PPS (0) was subtracted from the IR spectrum of dry PPS obtained in Reference Examples and Examples to obtain a peak intensity of a carboxylate of 1550 cm ⁻¹ .

Separately, IR measurement of sodium benzoate was performed, and the carboxylate content of PPS obtained in Reference Examples and Examples was calculated based on the calibration curve of carboxylate prepared from the peak intensity of 1550 cm ⁻¹ .

[Metal content]
5 g of PPS was precisely weighed in a platinum dish preheated to 550 ° C. and placed in an electric furnace at 550 ° C. for 24 hours for ashing. The ashed product was thermally decomposed with hydrofluoric acid, dissolved with dilute hydrochloric acid, and various metal contents were measured with an atomic absorption spectrometer Z2300 manufactured by Hitachi High-Technologies Corporation.

[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 .

[Weight average molecular weight]
The weight average molecular weight (Mw) was calculated in terms of polystyrene by gel permeation chromatography (GPC). The measurement conditions for GPC are shown below.
Apparatus: SSC-7100 (Senshu Science)
Column name: shodex UT-806M
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature: 250 ° C
Pump bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection amount: 300 μL (slurry: about 0.2% by weight).

[Evaluation of spinnability]
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., held for 5 minutes, and then rolled up at a take-up speed of 100 m / min with a roll installed under the die while being extruded at a discharge rate of 0.5 g / min. At this time, the spinnability was evaluated by ◯ when it was wound without being cut, and x when it was cut immediately after the start of winding.

[Reference Example 1 (Synthesis of PPS-1)]
In a 70 liter autoclave equipped with a stirrer and bottom plug valve, 8.26 kg (70.00 mol) of 47.5% sodium hydrosulfide, 3.03 kg (72.69 mol) of 96% sodium hydroxide, N-methyl-2 -Charge 11.45 kg (115.50 mol) of pyrrolidone (NMP) and 5.50 kg of ion-exchanged water, gradually heat to 225 ° C. over about 3 hours while passing nitrogen at normal pressure, 9.82 kg of water and NMP0 When the 28 kg was distilled, the heating was finished and the 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., p-dichlorobenzene (p-DCB) 10.08 kg (68.60 mol), p-chlorobenzoic acid 0.32 kg (2.06 mol), NMP 9.37 kg (94.50 mol). The reaction vessel was sealed under nitrogen gas, the temperature was raised from 200 ° C. to 270 ° C. at 0.6 ° C./min with stirring at 240 rpm, and the reaction was carried out at 270 ° C. for 1.5 hours. The reaction product was sampled when the temperature rose to 245 ° C., and the amount of p-DCB remaining in the sample was quantified with a gas chromatograph, and the consumption rate of p-DCB, that is, the conversion rate was calculated. The conversion was 64%. After completion of the reaction, the contents were cooled to room temperature, and the recovered material 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 75 ° C. ion-exchanged water for 15 minutes and filtered three times to obtain PPS-1 (cake).

  The polymer obtained by drying the PPS-1 cake at 120 ° C. had a carboxylate content of 170 μmol / g and a melt viscosity of 10 Pa · s.

[Reference Example 2 (Synthesis of PPS-2)]
In a 70 liter autoclave with a stirrer and bottom plug valve, 8.26 kg (70.00 mol) of 47.5% sodium hydrosulfide, 3.09 kg (74.06 mol) of 96% sodium hydroxide, N-methyl-2 -Charge 11.45 kg (115.50 mol) of pyrrolidone (NMP) and 5.50 kg of ion-exchanged water, gradually heat to 225 ° C. over about 3 hours while passing nitrogen at normal pressure, 9.82 kg of water and NMP0 When the 28 kg was distilled, the heating was finished and the 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., 9.98 kg (67.91 mol) of p-dichlorobenzene (p-DCB), 0.66 kg (3.43 mol) of 2,5-dichlorobenzoic acid, and 9.37 kg of NMP (94.94 mol). 50 mol), the reaction vessel was sealed under nitrogen gas, the temperature was raised from 200 ° C. to 235 ° C. at 0.6 ° C./min with stirring at 240 rpm, and the reaction was conducted at a constant temperature of 235 ° C. for 2 hours. Then, the temperature was raised from 235 ° C. to 255 ° C. at 0.8 ° C./min. As in Reference Example 1, when the temperature was raised to 245 ° C., the conversion of p-DCB was 94.5%. After completion of the temperature elevation, the contents were cooled to room temperature, and the same washing operation as in Reference Example 1 was performed to obtain PPS-2 (cake). The carboxylate content was 210 μmol / g, and the melt viscosity was 10 Pa · s.

[Reference Example 3 (synthesis of PPS-3)]
96% sodium hydroxide 2.94 kg (70.63 mol) was added to perform the dehydration step, p-DCB was added 10.39 kg (70.66 mol), and p-chlorobenzoic acid was not added. The same operation as in Reference Example 1 was performed to obtain PPS-3 (cake). As in Reference Example 1, when the temperature was raised at 245 ° C., the conversion of p-DCB was 64%. The carboxylate content of PPS-3 was 65 μmol / g, and the melt viscosity was 9 Pa · s.

[Reference Example 4 (Synthesis of PPS-4)]
In a 70 liter autoclave equipped with a stirrer and a bottom plug valve, 8.26 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 0.513 kg (6.25 mol), and ion-exchanged water 5.50 kg were charged to 245 ° C over about 3 hours while passing nitrogen at normal pressure. The mixture was gradually heated, and when 9.82 kg of water and 0.28 kg of NMP were distilled off, the heating was finished and cooling was started. At this time, the amount of water remaining in the system per mole of the alkali metal sulfide charged was 1.01 mol including the water consumed for 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., 10.49 kg (71.34 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the mixture was stirred at 240 rpm. The temperature was raised from 200 ° C. to 270 ° C. at a rate of 6 ° C./min, and reacted at 270 ° C. for 140 minutes. As in Reference Example 1, when the temperature was raised at 245 ° C., the conversion of p-DCB was 64%. Thereafter, 2.67 kg (148.4 mol) of water was injected while cooling from 270 ° C. to 250 ° C. over 15 minutes. Then, after gradually cooling from 250 ° C. to 220 ° C. over 75 minutes, the mixture was cooled to near room temperature, and the obtained contents were diluted with about 35 liters of NMP, stirred as a slurry at 85 ° C. for 30 minutes, and then 80 mesh wire mesh. The solid was obtained by filtration with an aperture of 0.175 mm. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The operation of diluting the obtained solid with 70 liters of ion-exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh wire net to collect the solid is repeated 3 times in total to obtain PPS-4 (cake). Obtained.

  The carboxylate content of the polymer obtained by drying the PPS-4 cake at 120 ° C. was 42 μmol / g, and the melt viscosity was 28 Pa · s.

[Reference Example 5 (Synthesis of PPS-5)]
The dehydration step was performed by adding 3.23 kg (77.49 mol) of 96% sodium hydroxide, 9.68 kg (65.86 mol) of p-DCB was added, and p-chloro was replaced with 2,5-dichlorobenzoic acid. PPS-5 (cake) was obtained in the same manner as in Reference Example 2, except that 1.07 kg (6.86 mol) of benzoic acid was added. As in Reference Example 2, when the temperature was raised to 245 ° C., the conversion of p-DCB was 94.5%. The carboxylate content of PPS-5 was 420 μmol / g, and the melt viscosity was 5 Pa · s.

[Example 1]
PPS-1 (cake) and 74 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, 85 μmol / g of calcium acetate monohydrate was added to 1 g of PPS, and the mixture was replaced with nitrogen. 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.

[Example 2]
The same operation as in Example 1 was conducted except that 85 μmol / g of magnesium acetate tetrahydrate was added to 1 g of PPS for washing.

[Example 3]
The same procedure as in Example 1 was performed except that 85 μmol / g of barium acetate was added to 1 g of PPS for washing.

[Example 4]
The same procedure as in Example 1 was performed except that 170 μmol / g of calcium acetate was added to 1 g of PPS for washing.

[Example 5]
The same procedure as in Example 1 was performed except that PPS-2 (cake) was used and washed with 105 μmol / g of calcium acetate monohydrate added to 1 g of PPS.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that PPS-3 cake was used and washed with 33 μmol / g of calcium acetate monohydrate added to 1 g of PPS.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that 170 μmol / g of acetic acid was added to 1 g of PPS for washing.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that 10 μmol / g of calcium acetate monohydrate was added to 1 g of PPS and washing was performed.

[Comparative Example 4]
PPS-4 (cake), 70 liters of ion-exchanged water was put in an autoclave equipped with a stirrer, 85 μmol / g of calcium acetate monohydrate was added to 1 g of PPS, and the mixture was stirred at 70 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh. Further, the obtained cake was diluted with 70 liters of ion-exchanged water, stirred at 70 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS.

[Comparative Example 5]
The same procedure as in Example 1 was performed except that PPS-5 (cake) was used and washed by adding 210 μmol / g of calcium acetate monohydrate to 1 g of PPS.
The results are shown in Table 1.

  A polymerization aid is added during polymerization by adding 0.1 to 5 moles of metal salt in a molar ratio with respect to the carboxylate content to PAS having a carboxylate content of more than 100 μmol / g and less than 400 μmol / g. It can be seen that a high melt viscosity PAS having excellent spinnability can be obtained without increasing the molecular weight by using. On the other hand, in PAS having a low carboxylate content, spinnability cannot be obtained unless the molecular weight is increased using a polymerization aid as in Comparative Example 4, and in PAS having too much carboxylate content as in Comparative Example 5. It can also be seen that since the molecular weight of the main chain is low, the spinnability is not exhibited even if the melt viscosity is sufficient.

Claims (8)

Washing polyarylene sulfide having a carboxylate content of more than 100 μmol / g and less than 400 μmol / g by adding an organic acid metal salt or an inorganic acid metal salt in a molar ratio to the carboxylate content of 0.1 to 5. A process for producing polyarylene sulfide characterized by the above. In a temperature range of 200 ° C. or higher and lower than 280 ° C., a sulfidizing agent, an alkali metal hydroxide, a dihalogenated aromatic compound, and a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound in an organic polar solvent. The method for producing polyarylene sulfide according to claim 1, wherein the resulting polyarylene sulfide is washed and the resulting polyarylene sulfide is washed. The polyarylene sulfide according to claim 2, wherein a polyarylene sulfide is obtained by reacting a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound with 0.01 mol or more and less than 10 mol with respect to 100 mol of the sulfidizing agent. Manufacturing method. The production of polyarylene sulfide according to claim 2, wherein a polyarylene sulfide is obtained by reacting a halogenated aromatic carboxylic acid compound or a halogenated aromatic carboxylate compound with 2 mol or more and less than 8 mol with respect to 100 mol of the sulfidizing agent. Method. 5. The method for producing polyarylene sulfide according to claim 1, wherein the organic acid metal salt or the inorganic acid metal salt is an alkaline earth metal salt. The ratio (B / A) of the melt viscosity (A) of the polyarylene sulfide before washing and the melt viscosity (B) of the polyarylene sulfide resin after washing is from 2.5 to 10. The manufacturing method of polyarylene sulfide in any one of -5. A polyarylene sulfide having a carboxylate content of more than 100 μmol / g and less than 400 μmol / g and a metal content of more than 40 μmol / g and less than 400 μmol / g. The polyarylene sulfide according to claim 7, wherein the metal content relative to the carboxylate content is 0.4 or more and less than 4 in terms of molar ratio.