JP2005344045A - Production method of polyarylene sulfide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a polyarylene sulfide resin, wherein a polymerization step is performed without using any polymerization auxiliary and without controlling water content in a polymerization system, the polyarylene sulfide resin with uniform resin properties can be obtained and post-treatment time can be shortened by improving filterability of the produced polymer at recovery. <P>SOLUTION: When a sulfiding agent is reacted with a dihaloaromatic compound in an organic amide solvent to produce polyarylene sulfide, a halide of an alkali metal other than lithium is added. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing polyarylene sulfide (hereinafter abbreviated as PAS) represented by polyphenylene sulfide (hereinafter abbreviated as PPS). In particular, the present invention relates to a method for producing polyarylene sulfide in which the post-treatment process time is shortened by improving the filtration performance of the reaction slurry.

  As a method for producing PAS, for example, a method in which a sulfidizing agent such as sodium sulfide is reacted with a dihaloaromatic compound such as p-dichlorobenzene in an organic solvent such as N-methyl-2-pyrrolidone is basically used. A method using an alkali metal carboxylate as a polymerization aid during the polymerization reaction, a method in which the polymerization reaction is performed in two stages, and a large amount of water is positively added in the second stage reaction, or a reactor can be used during the polymerization reaction. Generally, a method of condensing a part of the gas phase in the reaction vessel by cooling the gas phase part of the reactor and refluxing it to the liquid phase is generally used.

  In these methods, PAS is produced by reacting a sulfidizing agent with a dihaloaromatic compound in an organic amide solvent within a temperature range of about 180 to 280 ° C. However, this reaction is accompanied by a rapid exothermic reaction, and an undesirable side reaction is likely to occur. In that case, the shape of the obtained PAS particles is not constant, and the obtained PAS slurry is filtered and washed with water. In the process of separating the PAS by repeating the process, it may take too much time to be an economical process.

  In order to solve the above problems, attempts have been made to improve the filtration performance of PAS slurry. For example, a part of the gas phase of the reaction vessel is condensed by cooling the gas phase portion of the reaction vessel, this is refluxed to the liquid phase, and the reaction system is heated to a reaction temperature in the range of 180 to 275 ° C. A method of improving the filtration performance of the reaction slurry by obtaining a PAS polymer with stable particle properties by setting the speed at an average of 0.01 to 1.0 ° C./min is mentioned (for example, see Patent Document 1). . However, this method requires a careful control of the heating rate because it is necessary to reduce the heating rate in order to obtain high filtration performance.

In addition, in the method for producing PAS, a method is mentioned in which the particle size of the precipitated PAS polymer particles is increased by setting the stirring power of the stirring blade in the polymerization step to 0.2 to 1.0 kW / m ³ . (For example, refer to Patent Document 2). However, in this method, the stirring power is reduced in order to increase the particle size, so in the method of cooling and crystallizing the PAS polymer, a large amount of the PAS polymer deposited on the reaction vessel adheres, which adversely affects the next reaction. Is not preferable.

Japanese Patent Laid-Open No. 2002-3603 JP 2003-26803 A

  The object of the present invention is to make the properties of the PAS resin constant in a simple PAS resin production method without the need to control the water content of the polymerization system in the middle of the polymerization process without using a polymerization aid during polymerization. An object of the present invention is to provide a method for producing a PAS resin in which the post-treatment process time is shortened by improving the filtration performance at the time of polymer recovery.

As a result of intensive studies to solve the above problems, the present inventor has obtained the following knowledge.
(1) When an alkali metal halide other than lithium is added when PAS is produced by reacting a sulfidizing agent with a dihaloaromatic compound in an organic amide solvent, an alkali metal halide other than the added lithium is added. However, the alkali metal halide particles that are generated and precipitated with the progress of the polymerization reaction are greatly grown.
(2) In this state, when PAS is crystallized by cooling after the reaction, PAS precipitates and grows using the alkali metal halide particles as seeds, so that the PAS particle diameter increases and the filterability in the post-treatment process Will improve.
(3) As a result, the productivity of the PAS resin can be improved.

  The present invention is based on such knowledge. That is, the present invention provides a PAS characterized by adding an alkali metal halide excluding lithium when a PAS is produced by reacting a sulfidizing agent with a dihaloaromatic compound in an organic amide solvent. Provide a method.

  The production method of the PAS resin of the present invention does not use a polymerization aid, does not add water to the reaction system during the reaction, and greatly improves the filterability of the reaction slurry by a simple method. Since the post-processing time can be carried out in a short time, productivity is improved and this is an economically advantageous method.

  In the method for producing a PAS resin of the present invention, an alkali metal halide is usually produced together with the production of PAS in the polymerization method of PAS in which a sulfidizing agent and a dihaloaromatic compound are reacted. By adding the alkali metal halide at the time of the production of the alkali metal halide, the added alkali metal halide becomes a seed crystal, and the particles of the alkali metal halide that are produced and precipitate as the polymerization reaction proceeds are greatly grown. When PAS is crystallized by cooling after the reaction, PAS precipitates and grows using the alkali metal halide as a seed, so the PAS particle size is increased and the filterability in the post-treatment process is considered to be improved.

  The PAS polymerization method of the present invention is a method for producing a PAS by reacting a sulfidizing agent with a dihaloaromatic compound in an organic amide solvent, and adding the alkali metal halide excluding lithium to the resulting PAS. This increases the particle size of the PAS slurry and improves the filtration performance of the PAS slurry. Each requirement will be described below.

1. Alkali metal halides excluding lithium The alkali metal halides excluding lithium used in the present invention are not particularly limited. For example, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide, etc., rubidium fluoride, rubidium chloride, rubidium bromide, rubidium iodide, fluoride Examples include cesium, cesium chloride, cesium bromide, and cesium iodide, preferably an alkali metal halide having the same halogen as the dihaloaromatic compound used, or an alkali metal halogen having the same alkali metal as the sulfidizing agent used. A compound. More preferably, an alkali metal halide having the same halogen as the dihaloaromatic compound to be used and having the same alkali metal as the sulfidizing agent to be used can be mentioned. In particular, in the production method of PAS, it is most preferable to use alkali metal halide when p-dichlorobenzene is used as the dihaloaromatic compound and sodium sulfide and / or sodium hydrosulfide / sodium hydroxide is used as the sulfidizing agent. Sodium chloride is preferred as the chemical.

  In this case, alkali metal halides excluding lithium halide are insoluble in organic amide solvents and can be used without any particular limitation. Moreover, the said alkali metal halide may be used independently, and may use 2 or more types together.

  Since lithium halide dissolves in an organic amide solvent and acts as a phase separation agent, PAS fine particles and coarse particles are generated, which is not preferable because the filterability is lowered.

  The addition amount of the alkali metal halide excluding lithium is preferably 0.01 mol% or more because the effect of increasing the PAS particle size is remarkable and the filterability is improved, and the PAS particle size is sufficiently increased. Since it is achieved, it is preferably 20 mol% or less, and more preferably in the range of 0.5 to 5 mol%.

  When using a lithium salt as a sulfidizing agent, it is necessary to select an alkali metal halide excluding lithium. In this case, the amount of alkali metal halide excluding lithium is larger than the above range. It may be.

  The alkali metal halide other than lithium is added at the start of dehydration of the sulfiding agent, during the dehydration or after the dehydration, before adding the dihaloaromatic compound to start the reaction, during the reaction, or at the end of the reaction. . Or it can carry out at the arbitrary time before PAS crystallization after completion | finish of reaction.

  In order to obtain larger PAS particles, even during the addition period, salt particles such as sodium chloride that are by-produced as the reaction proceeds are grown using the alkali metal halide excluding the added lithium halide as a seed crystal. It is preferable to add an alkali metal halide before the start of the reaction. Moreover, the addition of alkali metal halides excluding lithium halide may be added all at once, or may be divided into arbitrary numbers and added at different addition times.

2. Organic Amide Solvent The organic amide solvent used in the present invention is known for PAS polymerization. For example, N-methyl-2-pyrrolidone (hereinafter referred to as NMP), N-ethylpyrrolidone, N, N-dimethylformamide, N, N-dimethyl (or diethyl) acetamide, N-methyl (or ethyl) caprolactam, 1,3-dimethyl-2-imidazolidinone, formamide, acetamide, hexamethylphosphoramide, tetramethylurea N, N′-ethylene-2-pyrrolidone, 2-pyrrolidone, ε-caprolactam, diphenylsulfone, and the like, and mixtures thereof, among which NMP is preferable.

3. Sulfiding agent Examples of the sulfiding agent include alkali metal sulfides, alkali metal hydrosulfides, and mixtures thereof.

  Examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, and cesium sulfide. These may be used alone or in combination of two or more. Also good. The alkali metal sulfide may be any of anhydride, hydrate, and aqueous solution. Among the alkali metal sulfides, sodium sulfide and potassium sulfide are preferable, and sodium sulfide is particularly preferable. These alkali metal sulfides can be obtained, for example, by reacting an alkali metal hydrosulfide with an alkali metal base, or hydrogen sulfide with an alkali metal base, but those prepared outside the reaction system may also be used.

  Examples of the alkali metal hydrosulfide include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and the like. These may be used alone or in combination of two or more. May be used. The alkali metal hydrosulfide may be any of anhydride, hydrate, and aqueous solution. Among the alkali metal hydrosulfides, sodium hydrosulfide and potassium hydrosulfide are preferable, and sodium hydrosulfide is particularly preferable. These alkali metal hydrosulfides can be obtained by reacting hydrogen sulfide with an alkali metal base, but those prepared outside the reaction system may also be used.

  Examples of the alkali metal base include alkali metal hydroxide. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and the like. These may be used alone or in combination of two or more. May be used. Among the alkali metal hydroxide compounds, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable, and sodium hydroxide is particularly preferable.

  In any of the above cases, an alkali metal base may be added in a small excess to remove impurities present in a small amount in the alkali metal sulfide or alkali metal hydrosulfide.

The sulfiding agent may be an anhydride, but a water-containing material is preferable from the standpoint of availability and controllability of the reaction. When an anhydride is used, water is added and used. Examples of the sulfidizing agent include lithium sulfide, sodium sulfide (Na ₂ S), potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. These alkali metal sulfides may be hydrates and aqueous solutions. In addition, hydrosulfides and hydrates corresponding to these can be used after neutralizing with the corresponding hydroxides. Among these alkali metal sulfides, sodium sulfide is inexpensive and industrially preferable.

4). Dihaloaromatic compounds Dihaloaromatic compounds include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 2,5-dichlorotoluene, p-dibromobenzene, 1,4-dichloronaphthalene, 1-methoxy-2 , 5-dichlorobenzene, 4,4'-dichlorobiphenyl, 4,4'-dibromobiphenyl, 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2,4- Dichloroaniline, 2,5-dichloroaniline, 3,5-dichloroaniline, 4,4'-dichlorophenyl ether, 4,4'-dichlorodiphenyl sulfoxide, 4,4'-dichlorophenyl ketone, and the like and their A mixture is included. Of these, those containing p-dihalobenzene represented by p-dichlorobenzene as the main component are preferred.

  In the method for producing polyarylene sulfide of the present invention, if necessary, in order to increase the molecular weight of PAS, it has 3 or more halogen substituents per molecule, for example, 1,3,5-trichlorobenzene. Polyhaloaromatic compounds such as 1,2,4-trichlorobenzene can be used. The polyhaloaromatic compound is preferably used in an amount of 0.005 to 1.5 mol%, particularly preferably 0.02 to 0.75 mol%, based on 1 mol of the alkali metal sulfide.

5). Polymerization Reaction The method for producing PAS by reacting an alkali metal sulfide and a dihaloaromatic compound in an organic amide solvent is not particularly limited. For example, a method described in Japanese Patent Publication No. 45-3368, a method using an alkali metal carboxylate described in Japanese Patent Publication No. 52-12240, and a polymerization aid such as lithium halide described in US Pat. No. 4,038,263. A method using a crosslinking agent, a method using a cross-linking agent such as a polyhaloaromatic compound described in JP-B-54-8719, and a multi-stage reaction under different amounts of water described in JP-B-63-33775. It can be produced by the method used.

  Among the above methods, a preferable method is a method described in JP-A-5-222196, in which a PAS is produced by reacting an alkali metal sulfide and a dihaloaromatic compound in an organic amide solvent. A method of condensing a part of the gas phase in the reaction vessel by cooling the gas phase portion of the reaction vessel and refluxing it to the liquid phase can be used. By using this method, a PAS having a relatively high melt viscosity can be produced, and therefore a PAS having a high mechanical strength such as tensile strength and impact strength can be obtained.

In this method, the liquid to be refluxed has a high water content compared to the liquid phase bulk due to the difference in vapor pressure between water and the amide solvent. This reflux solution with a high water content forms a layer with a high water content at the top of the reaction solution. As a result, the remaining alkali metal sulfide (for example, Na ₂ S), halogenated alkali metal (for example, NaCl), oligomer, and the like are contained in a large amount in the layer. In the conventional method, in a state where the produced PAS and the raw materials and by-products such as Na ₂ S are uniformly mixed at a high temperature of 230 ° C. or higher, not only a high molecular weight PAS can be obtained but also it is generated with great effort. The depolymerization of the PAS also occurs, and a by-product of thiophenol is observed. However, in the present invention, the above-mentioned disadvantageous phenomenon can be avoided by actively cooling the gas phase portion of the reaction vessel and returning a large amount of moisture-rich reflux liquid to the upper part of the liquid phase, thereby inhibiting the reaction. It is considered that such a factor can be removed truly efficiently and a high molecular weight PAS can be obtained. However, the present invention is not limited only by the effect of the above phenomenon, and a high molecular weight PAS can be obtained by various influences caused by cooling the gas phase portion.

  In this method, it is not necessary to add water during the reaction unlike the conventional method. However, adding water is not completely excluded. However, if the operation of adding water is performed, some of the advantages of the present invention are lost. Therefore, preferably the total water content in the polymerization reaction system is constant throughout the reaction.

  Cooling of the gas phase portion of the reactor can be performed by external cooling or internal cooling, and can be performed by a cooling means known per se. For example, a method of flowing a refrigerant through an internal coil installed at the top of a reaction can, a method of flowing a coolant through an external coil or jacket wound around the top of the reaction can, and a reflux condenser installed at the top of the reaction can A method such as spraying water on the upper part outside the reaction can or blowing a gas (air, nitrogen, etc.) is conceivable. Any method can be used as long as it has an effect of increasing the reflux amount in the can as a result. May be used. If the outside air temperature is relatively low (for example, normal temperature), it is possible to perform appropriate cooling by removing the heat insulating material conventionally provided at the top of the reaction can. In the case of external cooling, the water / amide solvent mixture condensed on the wall of the reaction vessel passes through the wall of the reaction vessel and enters the upper layer of the liquid phase. Accordingly, the water-rich mixture accumulates at the top of the liquid phase and keeps the water content relatively high. In the case of internal cooling, the mixture condensed on the cooling surface likewise travels through the cooling device surface or the reaction vessel wall and enters the liquid phase.

  On the other hand, the temperature of the liquid phase bulk is kept at a predetermined constant temperature or controlled according to a predetermined temperature profile. When making it constant temperature, it is preferable to perform reaction for 0.1 to 20 hours at the temperature of 230-275 degreeC. More preferably, it is 1 to 6 hours at a temperature of 240 to 265 ° C. In order to obtain higher molecular weight PAS, it is preferred to use a reaction temperature profile of two or more stages. When performing this two-stage operation, it is preferable that the first stage is carried out at 195 ° C. or higher, because the reaction rate is not too low, which is preferable from a practical point of view, sufficiently high molecular weight PAS is obtained, and side reaction rate does not increase To 240 ° C. or less. Furthermore, 210-240 degreeC is especially preferable. At the end of the first stage, the residual ratio of the dihaloaromatic compound in the polymerization reaction system is preferably 1 mol% or more because it is easy to finally obtain a high molecular weight PAS, and side reactions such as depolymerization occur in the second stage reaction. Since it is difficult, 40 mol% or less is preferable. In addition, it is preferable to carry out at a time when the molecular weight is within the range of 3,000 to 20,000. Among these, more preferably, the residual ratio of the dihaloaromatic compound in the polymerization reaction system is in the range of 2 to 15 mol% and the molecular weight is in the range of 5,000 to 15,000. Thereafter, the temperature is raised, and the final reaction is preferably carried out at 240 to 270 ° C. for 1 to 10 hours. The temperature range is preferably a reaction temperature of 240 ° C. or higher because it is easy to obtain a sufficiently high molecular weight PAS, and side reactions such as depolymerization are unlikely to occur, and a high molecular weight product can be obtained stably. It is preferable to react at 270 ° C. or lower.

  As an actual operation, first, dehydration or water addition is performed as necessary so that the water content of the polymerization system becomes a predetermined amount in an inert gas atmosphere. The amount of water is preferably 0.5 to 1.7 mol, particularly 0.8 to 1.2 mol, per mol of alkali metal sulfide. When the amount exceeds 1.7 mol, side reactions are remarkably generated, and by-products such as phenol in the reactive organisms increase with an increase in the amount of water in the system. If it is less than 0.5 mol, the reaction rate is too high, and a sufficiently high molecular weight product cannot be obtained, and undesirable reactions such as side reactions occur.

  In the case of a one-stage reaction at a constant temperature, the cooling of the gas phase portion during the reaction is desirably performed from the start of the reaction, but must be performed at least during the temperature increase of 250 ° C. or less. In the multistage reaction, it is desirable to cool from the first stage reaction, but it is preferable to carry out from the middle of the temperature increase after the completion of the first stage reaction at the latest. The degree of cooling effect is usually the most suitable index for the pressure in the reaction vessel. The absolute value of the pressure varies depending on the characteristics of the reaction vessel, the stirring state, the amount of water in the system, the molar ratio of the dihaloaromatic compound and the sulfidizing agent, and the like. However, compared with the case where the reactor is not cooled under the same reaction conditions, if the reaction vessel pressure decreases, the amount of the reflux liquid increases, which means that the temperature at the reaction solution gas-liquid interface decreases. It is considered that the degree of relative decrease indicates the degree of separation between the layer having a high water content and the layer not having the moisture content. Therefore, the cooling is preferably performed to such an extent that the internal pressure of the reaction can becomes lower than that in the case where cooling is not performed. The degree of cooling can be appropriately set by those skilled in the art according to the equipment to be used and the operating conditions.

  The obtained PAS may be heat-treated at a temperature lower than the melting point of PAS in a gas phase oxidizing atmosphere. The heat treatment temperature is preferably 180 to 270 ° C, particularly preferably 200 to 270 ° C. If the temperature is less than the above lower limit, the curing speed is insufficient and the time required for the heat treatment increases. If the temperature exceeds the upper limit, the curing speed becomes too high to control the melt viscosity, and the PAS gel cannot be controlled. Arise. Moreover, although the time which heat processing requires changes with said heat processing temperature etc., Preferably it is 0.5 to 300 hours, Most preferably, it is 1 to 96 hours. If the time is less than the above lower limit, the effect of heat treatment cannot be sufficiently obtained, and if the upper limit is exceeded, the PAS particles are easily fused with each other, and the secondary particles are remarkably enlarged or adhered to the container can wall. This is undesirable.

  The heat treatment is preferably carried out in a gas phase oxidizing atmosphere of an oxygen-containing gas such as air, pure oxygen or the like or a mixture of these and any suitable inert gas. Examples of the inert gas include water vapor, nitrogen, carbon dioxide and the like or a mixture thereof. The concentration of oxygen in the oxygen-containing gas is preferably 0.5 to 50% by volume, particularly preferably 10 to 25% by volume. If the oxygen concentration exceeds the above upper limit, the amount of radical generation increases, the thickening at the time of melting becomes remarkable, and the hue becomes dark, which is not preferable. If the oxygen concentration is less than the lower limit, the thermal oxidation rate becomes slow, which is not preferable.

6). Recovery of polyarylene sulfide (post treatment)
In the method of the present invention, the polyarylene sulfide can be recovered from the PAS slurry obtained as described above according to a conventional method. For example, the PAS slurry was filtered to obtain a PAS cake containing a solvent, and the PAS cake was obtained by heating in a nitrogen gas stream, preferably at a temperature of 150 to 250 ° C., preferably for 10 minutes to 24 hours. PAS powder can be obtained by a solvent drying treatment method in which PAS powder is repeatedly washed with water / filtered several times and then dried to obtain PAS. Alternatively, after the PAS slurry is filtered and the solvent is removed, water washing and / or filtration is repeated several times, and then dried to obtain PAS by a direct water washing treatment method in which PAS is obtained.

  Further, an acid treatment may be performed by adding an acid and / or a salt showing acidity in an aqueous solution to the post-reaction PAS slurry described in JP-A-10-130388. The amount of the acid or hydrogen salt added to the PAS slurry after the reaction is such that the pH of the PAS slurry after addition of the acid or hydrogen salt is 7.0 to 11.0. Preferably, the slurry is added so that the pH of the slurry is 7.5 to 10.0. If the pH of the slurry is less than 7.0, it is not preferable because the molecular weight of the obtained PAS is lowered, and the whiteness of the PAS cannot be improved. If the pH exceeds 11.0, the crystallization temperature Tc cannot be increased, and the whiteness of PAS is also low. The addition amount of the acid or hydrogen salt may be such an amount that the pH of the PAS slurry becomes 7.0 to 11.0 as described above, and the type of acid or hydrogen salt used or the PAS after the reaction. Depending on the pH of the slurry, etc., the upper limit is preferably 10 mol%, particularly preferably 6.0 mol%, and the lower limit is preferably 0.2 mol%, especially with respect to 1 mol of the charged alkali metal sulfide. Preferably it is 0.5 mol%.

  There is no restriction | limiting in particular as an acid to be used. For example, acetic acid, formic acid, oxalic acid, phthalic acid, hydrochloric acid, phosphoric acid, sulfuric acid, sulfurous acid, nitric acid, boric acid, carbonic acid and the like are used. In addition, a salt that shows acidity in an aqueous solution can be used, and preferred examples include zinc chloride, calcium chloride, magnesium chloride, barium chloride, and sodium hydrogen sulfate. For use in an actual machine, an organic acid that causes little corrosion to the metal member is preferable.

  As a method of adding an acid and / or a salt showing acidity in an aqueous solution to the PAS slurry after the reaction, a known method can be used. For example, a method of adding a predetermined amount of acid and / or the above salt to the cooled slurry after completion of the reaction and stirring it can be mentioned. Here, the temperature of the PAS slurry when the acid and / or salt is added is preferably room temperature to 200 ° C, particularly preferably 50 to 180 ° C. Addition above 200 ° C tends to cause side reactions with solvents and the like, and if it is less than room temperature, the fluidity of the PAS slurry is extremely poor and cannot be sufficiently mixed. After the addition, in order to uniformly mix the PAS slurry and the acid and / or salt, stirring is preferably continued for 10 minutes to 48 hours, particularly preferably for 30 minutes to 36 hours. The PAS produced by the method of the present invention has an increased particle size and excellent filtration performance.

7). Generated PAS
The PAS obtained by the method of the present invention has excellent particle properties, and when molding, conventional additives such as powdered fillers such as carbon black, calcium carbonate, silica, titanium oxide, or carbon fibers, glass Fibrous fillers such as fibers, asbestos fibers, and polyaramid fibers can be mixed. Furthermore, additives such as antioxidants, heat stabilizers, lubricants, mold release agents, colorants and the like can be blended as necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples. In addition, the test method in an Example is as follows.

(A) Filterability: 100 g of the reaction slurry obtained after polymerization was heated to 50 ° C., and then filtered under reduced pressure using a filter paper having a diameter of 60 mm and a holding size of 1 μm using an electric pump under conditions of 3.3 × 10 ⁴ Pa. Went. The filtration time and the amount of the filtrate until the filtration at this time was measured, and the filterability was determined by the following formula. Filterability (g / sec) = filtrate amount (g) / filtration time (sec)

(B) Melt viscosity: Viscosity (poise) measured after holding for 6 minutes at 300 ° C., load = 1.96 × 10 ⁶ Pa, L / D = 10/1, using a flow tester manufactured by Shimadzu Corporation, CFT-500C It is.

  (C) Particle size distribution: Using a wet particle size distribution measuring device (Microtrac SRA manufactured by Nikkiso Co., Ltd.), the particle size distribution of the obtained reaction slurry was measured to determine the average particle size.

Example 1
In a 150 liter autoclave, 15.415 kg of flaky sodium sulfide (60.75 wt% Na ₂ S), 7 g of sodium chloride (0.1 mol% relative to 1 mol of sodium sulfide) and N-methyl-2-pyrrolidone (hereinafter referred to as “sodium sulfide”) 38.0 kg), which may be abbreviated as NMP). While stirring under a nitrogen stream, the temperature was raised to 215 ° C. to distill 3.529 kg of water (1.17 mol of water per 1 mol of sodium sulfide). Thereafter, the autoclave was sealed and cooled to 180 ° C., and 17.913 kg of paradichlorobenzene (hereinafter sometimes abbreviated as p-DCB) and 16.0 kg of NMP were charged. Nitrogen gas was used at a liquid temperature of 150 ° C. to start pressurization to 9.8 × 10 ⁴ Pa, and when the liquid temperature reached 250 ° C., watering to the top of the autoclave was started. The reaction was carried out at this temperature for 2 hours. After completion of the reaction, watering was stopped and the mixture was cooled to room temperature. A part of the obtained reaction slurry was sampled to measure filterability and particle size distribution. The remaining reaction slurry is filtered to remove the solvent, and then washed with water and filtered seven times in a conventional manner, and then dried in a hot air circulating dryer at 120 ° C. for about 8 hours. Got. Table 1 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 2
The same operation as in Example 1 was performed except that 70 g of sodium chloride (1.0 mol% with respect to 1 mol of sodium sulfide) was used. Table 1 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 3
The same operation as in Example 1 was conducted except that 1.192 kg of sodium chloride (17.0 mol% with respect to 1 mol of sodium sulfide) was used. Table 1 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 4
Instead of sodium chloride, 1.753 kg of a 20% by weight aqueous sodium chloride solution (5 mol% with respect to 5.0 mol of sodium sulfide) was used to distill 4.866 kg of water (1 mol of water per mol of sodium sulfide). The reaction was conducted in the same manner as in Example 1 except for 2 mol). Table 1 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 5
A 150-liter autoclave was charged with 15.415 kg of flaky sodium sulfide (60.75 wt% Na ₂ S) and 38.0 kg of N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP). While stirring under a nitrogen stream, the temperature was raised to 216 ° C. to distill 3.680 kg of water (1.1 mol of water per 1 mol of sodium sulfide). Thereafter, the autoclave is sealed and cooled to 180 ° C., and 175 g of a 20% aqueous sodium chloride solution (0.5 mol% with respect to 1 mol of sodium sulfide) and paradichlorobenzene (hereinafter sometimes abbreviated as p-DCB). 913 kg and NMP 16.0 kg were charged (the water in the system was 1.16 mol per mol of sodium sulfide). The following operations were performed in the same manner as in Example 1. Table 2 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 6
The temperature was raised to 217 ° C. to distill 3.766 kg of water (1.06 mol of water per mol of sodium sulfide), and 351 g of a 20% sodium chloride aqueous solution (1.0 mol% with respect to 1 mol of sodium sulfide). The procedure was the same as in Example 5 except that it was used (the water in the system was 1.19 mol per mol of sodium sulfide). Table 2 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Example 7
The same procedure as in Example 1 was conducted except that 0.42 g of sodium chloride (0.006 mol% relative to 1 mol of sodium sulfide) was added. Table 2 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

Comparative Example 1
A polymer was obtained in the same manner as in Example 1 except that no alkali metal halide except lithium was added. Table 2 shows the melt viscosity of the polymer, the filtration rate, and the average particle size of the polymer.

  The present invention relates to a method for producing a polyarylene sulfide resin, and more particularly to a method for producing a polyarylene sulfide resin in which the post-treatment process time due to excellent filterability of a reaction slurry is shortened.

Claims (4)

A method for producing a polyarylene sulfide, comprising adding an alkali metal halide other than lithium when a polyarylene sulfide is produced by reacting a sulfidizing agent with a dihaloaromatic compound in an organic amide solvent. The method for producing a polyarylene sulfide according to claim 1, wherein the addition amount of the alkali metal halide excluding lithium is 0.01 to 20 mol% with respect to 1 mol of the sulfidizing agent. The method for producing a polyarylene sulfide according to claim 1 or 2, wherein the alkali metal halide other than lithium is added before the sulfidizing agent and the dihaloaromatic compound start the reaction. The method for producing a polyarylene sulfide according to claim 1, wherein the alkali metal in the alkali metal halide excluding lithium is at least one alkali metal selected from the group consisting of sodium, potassium, rubidium and cesium.