JPH0733878A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To easily produce the subject sulfide useful in the electric and electronic fields with a simple apparatus at a low cost by carrying out isothermic flushing of a specific organic solvent solution in a flush drum at a prescribed temperature. CONSTITUTION:This sulfide is produced by polymerizing N-methylaminobutyric acid lithium salt, hydrogen sulfide and a dihalogenated aromatic compound in an aprotic organic polar solvent, separating an organic solvent solution containing molten polyarylene sulfide polymer from the obtained polyarylene sulfide polymerization reaction product and subjecting the solution to isothermic flushing in a flush tank at a temperature above the melting point of the polyarylene sulfide polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyarylene sulfide, and more specifically, to a high-quality polyarylene sulfide suitable for a wide range of fields such as electric / electronic fields and high-rigidity materials fields, such as dryers. The present invention relates to a method for producing polyarylene sulfide that can be produced simply and economically with simple equipment that does not require expensive equipment.

[0002]

2. Description of the Related Art In the conventional method for producing polyarylene sulfide (hereinafter sometimes referred to as PAS), the washing efficiency is improved by directly washing the high temperature PAS polymerization reaction product. Was improved and the process was simplified. However, in this case, since the organic solvent solution containing PAS in a molten state, which is separated after washing the PAS polymerization reaction product, contains a large amount of volatile components, in order to produce a high-quality PAS, the volatile component is The component needs to be removed. In the conventional method,
The removal of this volatile component was carried out by washing the PAS polymer in the form of particles and drying it. However, according to such a method, there is a problem that a large amount of washing water and expensive equipment such as a dryer are required.

By the way, US Pat. No. 3,707,528
The publication discloses that such a volatile component is recovered by flushing a PAS polymerization reaction slurry liquid, and a PAS having a small content of impurities is easily produced.

However, in this case, since the PAS after flashing is recovered in a powder state, it is necessary to carry out a washing step and a drying step after all, which complicates the operation and equipment, so that high quality polyarylene sulfide can be obtained. There is still the problem that it cannot be manufactured simply and economically with simple equipment.

The present invention solves the above problems and provides a polyarylene sulfide suitable for a wide range of fields such as electric / electronic fields and high-rigidity materials fields with simple equipment which does not require expensive equipment such as a dryer. An object of the present invention is to provide a method for producing a polyarylene sulfide that can be produced simply and economically.

[0006]

The invention according to claim 1 is obtained by polymerizing a lithium N-methylaminobutyric acid salt, hydrogen sulfide and a dihalogen aromatic compound in an aprotic organic polar solvent. Separated from the polyarylene sulfide polymerization reaction product, an organic solvent solution containing a polyarylene sulfide polymer in a molten state is isothermally flashed in a flash drum at a temperature equal to or higher than the melting point of the polyarylene sulfide polymer. A method for producing arylene sulfide,
The invention according to claim 2 is a polyarylene sulfide polymer in a molten state, which is separated from a polyarylene sulfide polymerization reaction product obtained by polymerizing an alkali sulfide and a dihalogen aromatic compound in an aprotic organic polar solvent. Is a method for producing a polyarylene sulfide, which comprises isothermally flashing an organic solvent solution containing the above in a flash tank at a temperature equal to or higher than the melting point of the polyarylene sulfide polymer.

The method for producing the polyarylene sulfide according to the present invention will be described in detail below. The method for producing polyarylene sulfide according to the present invention has 1) PAS polymerization step and 2) flash step.

1) PAS Polymerization Step In this PAS polymerization step, a PAS polymerization reaction obtained by polymerizing a lithium salt of N-methylaminobutyric acid, hydrogen sulfide and an aromatic dihalogen compound in an aprotic organic polar solvent. A melted PAS polymer from the product (a) or from the PAS polymerization reaction product (b) obtained by polymerizing an alkali sulfide and the dihalogen aromatic compound in the aprotic organic polar solvent. The organic solvent solution is separated.

-PAS polymerization reaction product (a) -The lithium salt of N-methylaminobutyric acid is not particularly limited, and known compounds can be used.
The lithium salt of N-methylaminobutyric acid may be used alone or in combination of two or more. In the method of the present invention, the lithium salt of N-methylaminobutyric acid can be used as an anhydride, or as a hydrate or an aqueous solution. When the lithium salt of N-methylaminobutyric acid is used as a raw material, it is possible to prevent conventionally generated by-product of NaCl. As a result, PA
Since the S-polymerization reaction product can be directly subjected to the below-described flushing step on the separated organic solvent solution containing the PAS polymer in a molten state without washing, the efficiency is high.

The hydrogen sulfide is not particularly limited.

The dihalogenated aromatic compound is 2
Any aromatic compound having one halogen atom may be used, and examples thereof include known compounds. Specifically, dihalobenzenes such as m-dihalobenzene and p-dihalobenzene; 2,3-dihalotoluene,
2,5-dihalotoluene, 2,6-dihalotoluene,
3,4-dihalotoluene, 2,5-dihaloxylene, 1
-Ethyl-2,5-dihalobenzene, 1,2,4,5-
Alkyl-substituted dihalobenzenes such as tetramethyl-3,6-dihalobenzene and 1-n-hexyl-2,5-dihalobenzene; cycloalkyl-substituted dihalobenzenes such as 1-cyclohexyl-2,5-dihalobenzene; 1-phenyl-2, 5-dihalobenzene, 1-benzyl-2,5
-Aryl-substituted dihalobenzenes such as dihalobenzene and 1-p-toluyl-2,5-dihalobenzene; 4,4 '
-Dihalobiphenyls such as dihalobiphenyl; 1,4-
Dihalonaphthalene, 1,6-dihalonaphthalene, 2,6
Examples thereof include dihalonaphthalenes such as dihalonaphthalene. The two halogen elements in these dihalogenated aromatic compounds are respectively fluorine, chlorine, bromine or iodine, and they may be the same,
They may be different from each other. Among the dihalogenated aromatic compounds, dihalobenzenes are preferable, and p-dichlorobenzene or a mixture of 80 mol% or more of p-dichlorobenzene and m-dichlorobenzene is particularly preferable.

As the aprotic organic polar solvent,
Examples thereof include aprotic organic solvents such as amide compounds, lactam compounds, urea compounds and cyclic organic phosphorus compounds.

Examples of the amide compound include N, N
Formamides such as dimethylformamide; N, N
-Acetamides such as dimethylacetamide, N, N-diethylacetamide and N, N-dipropylacetamide; aromatic carboxylic acid amides such as N, N-dimethylbenzoic acid amide.

Examples of the lactam compound include caprolactam and N-methylcaprolactam, N-ethylcaprolactam, N-n-propylcaprolactam,
Caprolactams such as N-alkylcaprolactam such as N-isopropylcaprolactam, N-n-butylcaprolactam, N-isobutylcaprolactam and N-cyclohexylcaprolactam; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N- n-propyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-methyl-3-methyl- 2-pyrrolidone, N-ethyl-3-methyl-2-pyrrolidone, N-methyl-3,
Pyrrolidones such as N-alkyl such as 4,5-trimethyl-2-pyrrolidone; N-methyl-2-piperidone, N
-Ethyl-2-piperidone, N-isopropyl-2-piperidone, N-methyl-6-6-methyl-2-piperidone, N-methyl-3-ethyl-2-piperidone and the like can be mentioned.

Other aprotic organic polar solvents other than these include urea compounds such as tetramethylurea, N, N'-dimethylethyleneurea and N, N-dimethylpropyleneurea, 1-methyl-1-oxosulfolane. ,
1-ethyl-1-oxosulfolane, 1-phenyl-1
-Oxosulfolanes such as oxosulfolane, 1-methyl-1-oxophosphorane, 1-n-propyl-1-
Examples thereof include oxophosphorane and oxophosphorane such as 1-phenyl-1-oxophosphorane.

Of these solvents, amide compounds and lactam compounds can be mentioned as preferred examples. Among these, N-alkyllactams and N-alkylpyrrolidones are preferable, and N-methylpyrrolidone is particularly preferable. The aprotic organic polar solvent may be used alone or in combination of two or more kinds.

In the present invention, the lithium salt of N-methylaminobutyric acid, hydrogen sulfide and a dihalogen aromatic compound may be added or brought into contact with the aprotic organic polar solvent in any order.

The polymerization reaction can be carried out in a polymerization reaction tank under properly selected polymerization conditions. The polymerization reaction tank is not particularly limited, and an apparatus known per se can be used.

The polymerization conditions may include temperature, time, pressure and the like.

The temperature is usually 180 to 330.
C., preferably 210 to 290.degree. The temperature is 1
If it is lower than 80 ° C., the reaction rate becomes slow, so that it is not practical. On the other hand, if the temperature exceeds 330 ° C., side reactions and deterioration and decomposition of the produced polymer may occur, which may cause coloring and gelation.

The above-mentioned time cannot be unconditionally determined because it varies depending on the type and amount ratio of each component used, the type and amount of the acid scavenger, the reaction time, etc., but it is usually within 20 hours, preferably 0. 1 to 8 hours. If the time exceeds 20 hours, the volume of the reaction tank becomes large, which may be impractical.

The above-mentioned pressure is not particularly limited, but is usually the self-pressure of a polymerization reaction system such as a solvent to 50 kg / cm ^2.
(Absolute pressure).

The proportion of the lithium salt of N-methylaminobutyric acid used in the polymerization reaction is usually 0.05 to 3.0 mol, relative to 1 mol of hydrogen sulfide and dichlorobenzene.
It is preferably 1.5 to 2.2 mol. The ratio is 0.
If it is less than 05 mol, the effect of using the lithium salt of N-methylaminobutyric acid may not be sufficiently exhibited. On the other hand, if it exceeds 2.0 mol, the effect obtained by using the lithium salt of N-methylaminobutyric acid may not be changed.

The proportion of the dihalogenated aromatic compound used in the polymerization reaction is usually 0.90 to 1.3 mol, preferably 0.95 to 1.2 mol, relative to 1 mol of hydrogen sulfide. When the ratio is less than 0.90 mol, thiophenols may be by-produced. On the other hand, if it exceeds 1.3 mols, the molecular weight of the polyarylene sulfide obtained may decrease.

The ratio of each of the above components can be selected depending on the physical properties of the desired polyarylene sulfide such as the molecular weight and the amount of the branching agent described later.

The amount of the aprotic organic polar solvent is not particularly limited as long as it is a sufficient amount for the reaction to proceed uniformly, but is usually in the range of 1 to 20 mol per 1 mol of hydrogen sulfide. Is preferred. If the amount is less than 1 mol, the reaction may not proceed sufficiently. On the other hand, if it exceeds 20 mol, the volumetric efficiency may be deteriorated and the productivity may be lowered.

In the method of the present invention, the polymerization reaction can be carried out in an atmosphere of an inert gas such as nitrogen, argon or carbon dioxide. The polymerization reaction may be a one-step reaction carried out at a constant temperature, a multi-step reaction in which the temperature is raised stepwise, or a reaction mode in which the temperature is gradually and continuously raised.

In the method of the present invention, if desired, an active hydrogen-containing halogen aromatic compound, a polyhalogen aromatic compound having 3 or more halogen atoms in one molecule, a halogen aromatic nitro compound, etc. It is also possible to appropriately select and add a branching agent, a molecular weight modifier such as a monohalogenated aromatic compound or an active hydrogen-containing compound, a reducing agent and an inert organic solvent to the polymerization reaction system.

As the active hydrogen-containing halogen aromatic compound which is one of the branching agents, there can be mentioned, for example, a halogen aromatic compound having a functional group having active hydrogen such as an amino group, a thiol group and a hydroxyl group. , Dihaloanilines such as 2,6-dichloroaniline, 2,5-dichloroaniline, 2,4-dichloroaniline, 2,3-dichloroaniline; 2,3,4-trichloroaniline, 2,3,5-trichloro Aniline, 2, 4, 6
-Trihaloanilines such as trichloroaniline and 3,4,5-trichloroaniline; 2,2'-diamino-4,
In dihaloaminodiphenyl ethers such as 4'-dichlorodiphenyl ether, 2,4'-diamino-2 ', 4-dichlorodiphenyl ether, and mixtures thereof, one or more of the halogen atoms may be, in addition to the chlorine atom, It may be substituted with fluorine, bromine, etc.,
Further, a compound in which an amino group is replaced with a thiol group or a hydroxyl group can be exemplified. Further, an active hydrogen-containing halogen in which a hydrogen atom bonded to a carbon atom forming an aromatic ring in these active hydrogen-containing halogen aromatic compounds is substituted with another inert group, for example, a hydrocarbon group such as an alkyl group. Aromatic compounds can also be used. Of these various active hydrogen-containing halogen aromatic compounds, active hydrogen-containing dihalogen aromatic compounds are preferable, and dichloroaniline is particularly preferable.

Examples of the polyhalogenated aromatic compound that can be used as the branching agent include 1,2,4
-Trichlorobenzene, 1,3,5-trichlorobenzene, 1,4,6-trichloronaphthalene and the like can be mentioned.

Further, the halogen aromatic nitro compound which can be used as a branching agent is, for example, 2,4
-Mono- or dihalonitrobenzenes such as dinitrochlorobenzene and 2,5-dichloronitrobenzene; dihalonitrodiphenyl ethers such as 2-nitro-4,4'-dichlorodiphenyl ether; 3,3'-dinitro-
Dihalonitrodiphenylsulfones such as 4,4′-dichlorodiphenylsulfone; Mono- or dihalonitropyridines such as 2,5-dichloro-3-nitropyridine and 2-chloro-3,5-dinitropyridine, or various types Examples thereof include dihalonitronaphthalene. These halogen-aromatic nitro compounds are reduced in the reaction system and act as a branching agent, and are superior in branching efficiency to other branching agents. In the polyhalogenated aromatic compound and the halogenated aromatic nitro compound, the halogen atoms may be the same or different, and may be a chlorine atom, fluorine, bromine or the like.

By using these active hydrogen-containing halogen aromatic compounds, polyhalogen aromatic compounds, halogen aromatic nitro compounds, etc., the degree of branching of the resulting polymerization reaction product can be increased or the molecular weight can be further increased. Then, various properties of the polyarylene sulfide polymerization reaction product produced by the method of the present invention can be further improved.

The proportion of the branching agent used is usually 0.0005 to 0.05 mol, and 0.001 to 0.02 mol, per 1 mol of the dihalogenated aromatic compound used in the method of the present invention. preferable.

Examples of the monohalogenated aromatic compound which is one of the molecular weight regulators include chlorobenzene, bromobenzene, α-bromobenzene, α-chlorotoluene,
o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, α-bromotoluene, o-bromotoluene,
Examples thereof include m-bromotoluene and p-bromotoluene.

Examples of the active hydrogen-containing compound include thiophenol, phenol and aniline.

As the branching agent or the molecular weight adjusting agent, in addition to the above compounds, for example, a compound having three or more reactive halogen atoms such as cyanuric chloride can be used. In the method of the present invention, these branching agents or molecular weight modifiers may be used alone or in combination of two or more.

Examples of the reducing agent include hydrazine,
Examples thereof include metal hydride, alkali formate, sulfur and the like. Among these, metal hydrides are preferable, and sodium borohydride and calcium hydride are particularly preferable.

Examples of the inert solvent include benzene, toluene, xylene, biphenyl, terphenyl,
Examples thereof include hydrocarbons such as naphthalene and anthracene, ethers such as diphenyl ether, p-diphenoxybenzene, polyethylene glycol and dioxane, and among them, high boiling point inert organic solvents are preferable.

—PAS Polymerization Reaction Product (b) — Examples of the alkali sulfide include alkali metal sulfides and alkaline earth metal sulfides.

Examples of the alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide and cesium sulfide. Among these, lithium sulfide and sodium sulfide are preferable,
Sodium sulfide is particularly preferable. These may be used alone or in combination of two or more.

Examples of the alkaline earth metal sulfides include calcium sulfide, strontium sulfide, barium sulfide and magnesium sulfide. Among these, calcium sulfide and barium sulfide are preferable, and calcium sulfide is particularly preferable. These may be used alone or in combination of two or more.

The alkali metal sulfide or alkaline earth metal sulfide may be obtained by reacting each of the alkali metal hydrosulfide or alkaline earth metal hydrosulfide with a base.

Examples of the alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, and cesium hydrosulfide. Examples of the alkaline earth metal hydrosulfides include calcium hydrosulfide, strontium hydrosulfide, barium hydrosulfide, and barium hydrosulfide.

Examples of the base include various compounds such as inorganic bases and organic bases.

As the inorganic base, alkali metal hydroxide and the like can be preferably used, and examples thereof include lithium hydroxide, sodium hydroxide, potassium hydroxide and rubidium hydroxide.

Examples of the organic base include metal salts of ω-hydroxycarboxylic acid and alkali metal salts of aminocarboxylic acid.

In the present invention, the alkali sulfide and the dihalogenated aromatic compound may be added or brought into contact with the aprotic organic polar solvent in any order.

The above-mentioned polymerization reaction can be carried out by a method known per se under polymerization conditions appropriately selected using a polymerization reaction tank. The polymerization reaction tank is not particularly limited, and an apparatus known per se can be used.

Unlike the PAS polymerization reaction product (a), the PAS polymerization reaction product (b) obtained as described above contains an alkali halide as a by-product. Therefore,
The alkali halide is used as the PAS polymerization reaction product (b).
It is necessary to remove it from the inside. The method of performing such removal is not particularly limited, and examples thereof include a method using a solid-liquid separation device known per se, a method of performing hot filtration or heat extraction, and the like.

The method for separating the organic solvent solution containing the PAS polymer in a molten state from the polyarylene sulfide polymerization reaction product obtained as described above is not particularly limited, and an appropriate method can be selected. For example,
It can be carried out by allowing the PAS polymerization reaction product to stand still, or by adding a phase separation agent such as water to the high temperature PAS polymerization reaction product in a polymerization reaction tank and mixing them to remove the aqueous phase. .

2) Flush Step In this flush step, an organic solvent solution containing a PAS polymer in a molten state is isothermally flashed in a flash tank under appropriately selected flash conditions so as to be contained in the organic solvent solution. Volatile components are removed and PAS granules are precipitated.

As the above-mentioned flash tank, if a flash distillation can be carried out, a flash device known per se having a properly selected capacity, a polymer heater heat transfer area and the like can be mentioned. For example, a flash drum or the like that can automatically control various conditions such as temperature and pressure can be preferably mentioned.

Examples of the flush conditions include pressure, temperature, time, concentration of the organic solvent solution, and processing speed of the organic solvent solution.

The pressure is usually lower than the polymerization reaction pressure in the PAS polymerization step, and
0 × 10 ⁻³ Torr to atmospheric pressure is preferable, and particularly 1 to 10
0 Torr is preferred. If the pressure is higher than the polymerization reaction pressure in the PAS polymerization step, flushing may be incomplete and the volatile component may not be sufficiently removed from the organic solvent solution.

The above-mentioned temperature is usually a temperature above the melting point of PAS, preferably 285 to 370 ° C., particularly 29
0-350 degreeC is preferable. The temperature can be adjusted by appropriately setting the polymer heater temperature. If the temperature is lower than the melting point of PAS, PAS may be precipitated while containing volatile components, and in this case, it is not possible to produce high-quality PAS containing no impurities.

The time is usually 0.01 to 120.
Minutes, preferably 0.01 to 30 minutes, particularly 0.05
~ 20 minutes is preferred. If the time is less than 0.01 minutes, the flushing may be incomplete and the volatile components may not be sufficiently removed from the organic solvent solution. On the other hand, even if it exceeds 120 minutes, the effect corresponding to it may not be obtained.

Regarding the concentration of the organic solvent solution, the weight ratio of aprotic organic polar solvent / (PAS + aprotic organic polar solvent) is usually 100 wtppm to 70 wt%, preferably 1000 wtppm to 50 wt%, Particularly, 2000 wtppm to 50 wt% is preferable.
If the concentration is less than 70 wt%, the amount of volatile components that must be removed is too large, and the flash tank, heating heat exchanger, etc. become too large, which may not be economical.

The volatile component can be removed by the above flash process. The volatile component is usually
It is a solution component containing the aprotic organic polar solvent in a high proportion of 95% by weight or more and a small amount of a dihalogenated aromatic compound as an impurity. Specifically, the aprotic organic polar solvent is N-methyl-2-pyrrolidone (hereinafter,
Sometimes referred to as NMP. ), The dihalogenated aromatic compound is p-dichlorobenzene (hereinafter sometimes referred to as PDCB), which is a solution component containing 95% by weight or more of NMP and 5% by weight or less of PDCB.

Among the volatile components removed here, the aprotic organic polar solvent can be reused by performing distillation or the like after removal, and in this case, cost reduction can be achieved.

In the present invention, the removal of the volatile components may be carried out by a one-step flash process or by two or more flash processes. In order to sufficiently remove the volatile components, a flash step of two or more steps is preferable.

This flush process may be carried out batchwise or continuously. In the case of the continuous type, the organic solvent solution is continuously supplied to the flash tank set to a predetermined condition, the extraction pump such as a gear pump is started to extract the PAS polymer, and the vaporization is performed using a vacuum pump or the like. Extract the sex component. In this case, the supply amount of the organic solvent solution and the extraction amount of the PAS polymer can be appropriately selected.

The method for obtaining PAS particles from the PAS polymer melt from which the volatile components have been removed, which is obtained in this flash step, is not particularly limited, but examples thereof include strand cutting and underwater cutting. be able to. In the present invention, since the PAS granules from which the volatile components have been removed can be obtained, it is not necessary to carry out complicated steps such as washing and drying the slurry liquid after this flushing step. As a result, an expensive device such as a dryer is not required, and the cost can be reduced and the operation can be simplified. In the present invention, PA
A PAS washing step may be provided between the S-polymerization step and the flush step, in which case the resulting PAS granules will be of a higher quality free of further impurities.

As described above, in the present invention, 1)
By performing only the PAS polymerization step and the 2) flash step, a high-quality PAS polymer can be simply and economically produced with simple equipment that does not require expensive equipment such as a dryer. When the PAS polymer produced by the method of the present invention is used in various products,
For example, other polymers, pigments, graphite, metal powders, glass powders, quartz powders, fillers such as glass fibers, stabilizers, mold release agents, etc. can be blended and molded. The PAS polymer obtained by the method of the present invention can be used as a matrix resin for various molded products and composite materials, and can be used as films, sheets, fibers, various molded products, and the like. -It can be suitably used in a wide range of fields including the electronic field and the field of highly rigid materials.

[0064]

EXAMPLES Examples and comparative examples of the present invention will be described below. The invention is in no way limited to these examples.

(Examples 1 to 7) 1) PPS polymerization step A 10 L autoclave was used as a polymerization reaction tank, in which p-dichlorobenzene (hereinafter sometimes referred to as PDCB) 860.13 g (5. 86 mol),
Lithium N-methylaminobutyric acid salt (hereinafter sometimes referred to as LMAB) 1380.5 g (11.952 mo)
l) and N-methyl-2-pyrrolidone (hereinafter, NMP
Sometimes called. ) Dissolved in 3000 ml, and further contained 199.7 g (5.86 mol) of hydrogen sulfide. Next, this solution is sealed in a closed system at 140-1.
After stirring at 50 ° C for 1 hour, prepolymerization was performed at 200 ° C for 5 hours. Then, a PPS polymerization reaction product was obtained by further performing a polymerization reaction at 260 ° C. for 3 hours.

After completion of the polymerization reaction, the PPS polymerization reaction product was allowed to stand to separate it into a reaction solvent containing no PPS polymer and an organic solvent solution containing the PPS polymer in a molten state. A part of the organic solvent solution was extracted from the extraction line provided at the bottom of the polymerization reaction tank, cooled, washed with water and acetone, dried, and its molecular weight was measured to be η _inh = 0.25. It was

2) Flushing process The separated organic solvent solution was removed from a 10 L autoclave through a heat-insulated stainless steel tube having an inner diameter of 8 mm.
L-scale flash drum (Mitsui Shipbuilding Co., Ltd .; S
US316L). At this time, the moving amount of the organic solvent solution was controlled to be constant by a needle valve installed in the middle of the stainless pipe.

Then, a flash process was carried out in the flash drum under the conditions shown in Table 1. Then, the PAS melt from which the volatile components were removed was strand-cut to obtain PPS granules. Regarding the amount of volatile components remaining in the obtained PPS granules,
Analysis was carried out by purge trap gas chromatography. The results are shown in Table 1.

Thousands of ppm by the first flash process
It was confirmed that the amount of volatile components remaining to some extent could be reduced. Further, when the second flash process was performed, the amount of the residual volatile component was 60 pp.
It was confirmed that it could be reduced to about m.

[0070]

[Table 1]

(Comparative Example 1) P obtained in the same manner as in Example 1
The PPS obtained by cooling the PS polymerization reaction product with stirring
The granulate was washed with water and dried in a vacuum dryer.
The amount of volatile components remaining in the dried PPS granules was analyzed by purge trap gas chromatography in the same manner as in Example 1. The results are shown in Table 2.

[0072]

[Table 2]

Example 8 1) PPS Polymerization Step Using the amounts and types of alkali sulfide, dihalogenated aromatic compound and aprotic organic polar solvent shown in Table 3,
Mixing operation, distillation operation and polymerization reaction operation were performed according to the conditions shown in Table 3. A 2 L autoclave made of SUS316L was used as the polymerization reaction tank.

The obtained PPS polymerization reaction product was transferred to a pressure filter equipped with a 10 μm-oriented filter while keeping it at a high temperature (260 ° C.) to remove by-produced NaCl.

[0075]

[Table 3]

2) Flushing step The organic solvent solution containing PAS after removal was used in Example 1.
Led to a flash drum as well. And Example 1
A flash process was performed in the same manner as in 1. to obtain PPS granules. The amount of volatile components remaining in the obtained PPS granules was analyzed by purge trap gas chromatography. The results are shown in Table 1.

[0077]

According to the present invention, polyarylene sulfide suitable for a wide range of fields such as electric / electronic fields and high-rigidity materials fields can be simply and economically provided with simple equipment which does not require expensive equipment such as a dryer. It is possible to provide a method for producing a polyarylene sulfide that can be produced by

Claims (2)

[Claims] 1. A molten poly-separated from a polyarylene sulfide polymerization reaction product obtained by polymerizing a lithium N-methylaminobutyric acid salt, hydrogen sulfide and a dihalogen aromatic compound in an aprotic organic polar solvent. A method for producing a polyarylene sulfide, which comprises isothermally flashing an organic solvent solution containing an arylene sulfide polymer in a flash tank at a temperature equal to or higher than the melting point of the polyarylene sulfide polymer. 2. A polyarylene sulfide polymerization reaction product obtained by polymerizing an alkali sulfide and a dihalogen aromatic compound in an aprotic organic polar solvent,
A method for producing polyarylene sulfide, which comprises isothermally flashing an organic solvent solution containing a molten polyarylene sulfide polymer in a flash tank at a temperature equal to or higher than the melting point of the polyarylene sulfide polymer.