JP2002187949A - Purification method for polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purification method for a polyarylene sulfide(PAS) whereby the corrosion of a production apparatus and the corrosion of a metal mold during molding are inhibited; and to obtain a PAS which has been improved in quality, especially in the reactivity with an epoxysilane coupling agent, and gives a molded item improved in mechanical strengths. SOLUTION: At any one of steps of purification process after solvent removal, a PAS is purified by bringing it into contact with gaseous carbon dioxide or carbonated water under a pressure higher than 0.1 MPa but not higher than 2.0 MPa at 10-100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying polyarylene sulfide (hereinafter abbreviated as PAS). More specifically, as compared with conventional purification methods using various strong acids (hydrochloric acid, sulfuric acid, etc.), it is possible to reduce the corrosiveness to manufacturing equipment and a mold at the time of molding, and to improve the quality of PAS. To a purification method capable of: Another object of the present invention is to provide various molding materials and films,
Another object of the present invention is to provide a PAS suitable as a material for a wide range of uses such as fibers, electric / electronic parts, automobile parts, and paints.

[0002]

2. Description of the Related Art A typical polyphenylene sulfide (hereinafter abbreviated as PPS) among PASs is usually N-methyl-2-pyrrolidone, N-methyl-2-pyrrolidone, as described in JP-B-52-12240. In a relatively polar organic solvent such as N, N-dimethylacetamide, N-methyl-ε-caprolactam or the like, an alkali metal sulfide represented by sodium sulfide or an alkali metal hydrosulfide represented by sodium hydrosulfide is hydroxylated. It can be obtained by, for example, a method of reacting an alkali metal hydroxide represented by sodium with a polyhalo aromatic compound represented by p-dichlorobenzene.

[0003] The polymerization reaction is usually carried out under high-temperature, high-pressure and alkaline conditions. As the polymerization reaction proceeds, salt is produced, and the so-called "crude reaction product" after the polymerization reaction contains unreacted components other than salt. It contains raw materials, by-products, oligomers and the like.

[0004] The crude reaction product after the polymerization reaction is taken out to an appropriate container, and the solvent contained therein is separated and recovered by using an appropriate device such as a vacuum distillation device, a filter, a centrifugal separator or the like (here, a solvent). This operation is referred to as “desolvation”) or, if necessary, is further purified and reused.

On the other hand, the “crude polyarylene sulfide” after the removal of the solvent is generally dried after repeated washing and filtration to remove impurities such as salt and alkaline substances.

PAS is used in fibers, films, paints, compounds for injection molding materials and fiber-reinforced composite materials, etc. due to its excellent chemical resistance, electrical properties and mechanical properties. The impurities produced are PAS due to gas generation during melt processing, corrosion of injection molds and processing equipment, poor adhesion to paint supports, poor adhesion to reinforcing fibers in composite materials, etc. It is desired to reduce the amount of impurities therein.

For this reason, as a method for purifying PAS, washing methods using various organic solvents have been conventionally proposed. However, the use of the organic solvent causes environmental pollution and adverse effects on the human body.
There have been unfavorable problems such as the production cost required for solvent recovery and the adverse effect on quality due to the solvent remaining in the product.

Further, a method has been proposed in which the amount of impurities is reduced by bringing the reaction mixture into contact with an acid (Japanese Patent Application Laid-Open No. HEI 6-192421). In addition to having a serious problem in terms of properties, it has caused deterioration of the color tone of the obtained PAS and deterioration of the characteristics of the product.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to suppress the corrosion of a PAS refining facility and a mold at the time of molding without using a strong acid, and to improve the quality of PAS (particularly, epoxy silane). Improvement of reactivity with silane coupling agent,
To provide a polyarylene sulfide which is excellent in shortening the isothermal crystallization time.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted the following steps to remove the solvent containing a PAS-containing crude reaction product obtained by reacting a polyhaloaromatic compound with a sulfidizing agent in an organic polar solvent. By introducing carbon dioxide gas or carbonated water into the system and bringing the carbon dioxide gas or carbonated water into contact with the PAS in a state of being pressurized under a saturated vapor pressure, corrosiveness to the purification equipment is reduced and PAS (Particularly, improved reactivity with an epoxysilane-based silane coupling agent, shortened isothermal crystallization time, and the like) were remarkably improved, and arrived at the present invention.

That is, according to the present invention, a crude reaction product containing a polyarylene sulfide obtained by reacting a polyhaloaromatic compound with a sulfidizing agent in an organic polar solvent is desolvated and then subjected to carbon dioxide gas or carbon dioxide. A method for purifying polyarylene sulfide, comprising introducing water into a system and bringing carbon dioxide gas or carbonated water into contact with the polyarylene sulfide.

[0012]

DETAILED DESCRIPTION OF THE INVENTION PAS is usually N-methyl-2.
-Synthesized by reacting at least one polyhaloaromatic compound and at least one sulfidizing agent in an organic polar solvent such as pyrrolidone under suitable polymerization conditions. After the polymerization reaction, a method is generally employed in which a crude reaction product is taken out, and the solvent is removed by a suitable method such as solvent distillation or filtration under reduced pressure.

In the present invention, after performing an operation of desolvating a crude reaction product containing PAS or an organic polar solvent, etc., carbon dioxide gas or carbonated water is introduced into the system in a purification step by washing and filtration to obtain a saturated solution. By contacting carbon dioxide gas or carbonated water with the PAS in the system under the vapor pressure, the quality of the PAS is improved, and it is possible to cope with equipment of relatively inexpensive materials such as SUS316, which is less corrosive to manufacturing equipment. Yes, and mold corrosion during molding can be reduced.

The polyhalo aromatic compound used in the present invention is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring, and specifically, p-dichlorobenzene , O-dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromonaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromodiphenylbenzene, Examples include dichloroaromatic compounds such as dichlorobenzophenone, dibromobenzophenone, dichlorodiphenylether, dibromodiphenylether, dichlorodiphenylsulfide, dibromodiphenylsulfide, dichlorbiphenyl, and dibromobiphenyl, and mixtures thereof. Is, these compounds may be block copolymerized. Of these, preferred are dihalogenated benzenes, and particularly preferred are those containing 80 mol% or more of p-dichlorobenzene.

Further, by forming a branched structure,
For the purpose of increasing the viscosity of the AS, a polyhalo aromatic compound having three or more halogen substituents in one molecule may be used as a branching agent, if desired. Such polyhalo aromatic compounds include, for example, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,4,4
6-trichloronaphthalene and the like.

Further, there may be mentioned polyhaloaromatic compounds having a functional group having an active hydrogen such as an amino group, a thiol group or a hydroxyl group, and specific examples thereof include 2,6-dichloroaniline and 2,5-dichloroaniline. Dihaloanilines such as dichloroaniline, 2,4-dichloroaniline and 2,3-dichloroaniline; 2,3,4-trichloroaniline;
Trihaloanilines such as 3,5-trichloroaniline, 2,4,6-trichloroaniline and 3,4,5-trichloroaniline; 2,2′-diamino-4,4′-dichlorodiphenyl ether, 2,4 ′ -Diamino-2 ', 4
And dihaloaminodiphenyl ethers such as dichlorodiphenyl ether, and compounds in which an amino group in a mixture thereof is replaced with a thiol group or a hydroxyl group.

Further, in these active hydrogen-containing polyhaloaromatic compounds, a hydrogen atom bonded to a carbon atom forming an aromatic ring is substituted with another inert group, for example, a hydrocarbon group such as an alkyl group. Hydrogen containing polyhalo aromatic compounds can also be used.

Among these various active hydrogen-containing polyhaloaromatic compounds, preferred are active hydrogen-containing dihaloaromatic compounds, and particularly preferred is dichloroaniline.

Examples of the polyhalo aromatic compound having a nitro group include 2,4-dinitrochlorobenzene,
Mono- or dihalonitrobenzenes such as 2,5-dichloronitrobenzene; dihalonitrodiphenylethers such as 2-nitro-4,4'-dichlorodiphenylether;3,3'-dinitro-4,4'-dichloro Dihalonitrodiphenylsulfones such as diphenylsulfone;
2,5-dichloro-3-nitropyridine, 2-chloro-
Mono- or dihalonitropyridines such as 3,5-dinitropyridine; and various dihalonitronaphthalenes.

The alkali metal sulfide used in the present invention includes lithium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide and a mixture thereof. Such an alkali metal sulfide can be used as a hydrate, an aqueous mixture or an anhydride. Further, the alkali metal sulfide can also be derived by a reaction between the alkali metal hydrosulfide and the alkali metal hydroxide.

Normally, a small amount of alkali metal hydroxide may be added in order to react with a small amount of alkali metal sulfide or alkali metal thiosulfate in the alkali metal sulfide.

The organic polar solvent used in the present invention includes N-methyl-2-pyrrolidone, formamide, acetamide, N-methylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, tetramethylurea, N-dimethylpropyleneurea, amide urea of 1,3-dimethyl-2-imidazolidinonic acid, and lactams; sulfolane such as sulfolane, dimethylsulfolane; Examples thereof include nitriles such as nitriles; ketones such as methylphenyl ketone and mixtures thereof.

In the presence of these organic polar solvents, the conditions for the polymerization of the above sulfidizing agent and the polyhaloaromatic compound are generally at a temperature of 200 to 330 ° C., and the pressure is set at the polymerization solvent and the polyhaloaromatic compound as the polymerization monomer. Should be substantially maintained in the liquid phase, and is generally selected from the range of 0.1 to 20 MPa, preferably 0.1 to 2 MPa. The reaction time varies depending on the temperature and pressure, but generally ranges from 10 minutes to 72 hours, preferably from 1 hour to 48 hours.

In the present invention, the crude reaction product may be reacted in the presence of a sulfidizing agent and an organic polar solvent while continuously or intermittently adding a polyhaloaromatic compound and an organic polar solvent. .

In the present invention, the crude reaction product containing PAS obtained by the polymerization reaction is subjected to suitable means (e.g., vacuum distillation, centrifugation, screw decanter, vacuum filtration, pressure filtration, etc.). An appropriate method can be selected) by performing "desolvation" and separating and recovering the organic polar solvent.
After performing an operation of removing by-products, unreacted substances, and the like by repeating washing with water, purification with carbon dioxide or carbonated water is performed, and if necessary, further washing with water is performed, followed by drying to obtain a product. In the present invention, an appropriate amount of water may be added to the crude reaction product to remove the solvent when the crude reaction product is desolvated. Further, at any stage of the purification process, washing with a solvent (for example, N-methyl-2-pyrrolidone) instead of water may yield a dimer, 3
Oligomer components such as oligomers are also removed.
It is preferable to use AS from the viewpoints of suppressing generated gas during molding and improving the physical properties of molded articles.

The purification conditions using carbon dioxide or carbonated water in the present invention are as follows:
It is desirable that the pressure be higher than 0.1 MPa and not higher than 2.0 MPa. If the temperature and pressure purification conditions are within these ranges, PAS of excellent quality (especially, improved mechanical properties due to improved reactivity with the epoxysilane-based silane coupling agent, shortened isothermal crystallization time, etc.) Is obtained.

One of the advantages of the present invention is that when the method for purifying with carbon dioxide or carbonated water of the present invention is used, there is almost no corrosion to metals under normal refining temperature conditions (100 ° C. or less), and the current apparatus In addition to being compatible with
Since a relatively inexpensive material having a corrosion resistance of about 316 can withstand corrosion, there is an advantage in terms of equipment cost in terms of the material of the apparatus as compared with other acids.

One of the advantages of the present invention is that when other acids remain in the PAS (especially chloride ions and sulfate ions are likely to remain in the polymer), mold corrosion during molding and molded products may occur. However, in the case of the purification method using carbon dioxide gas or carbonated water according to the present invention, it is easy to remove even in the subsequent washing step, and PA is also used in the drying step.
Since it is decomposed and scattered from S, it is hard to cause corrosion of a mold such as other acids and deterioration of physical properties of a molded product.

Further, one of the advantages of the present invention is that when a strong acid other than carbon dioxide or carbonated water is used, a large amount of water is removed after cleaning with the strong acid in order to remove the acid remaining in the PAS. In contrast, in the case of the purification method using carbon dioxide or carbonated water according to the present invention, it is necessary to remove the remaining acid by requiring the number of times of washing, and to use after the cleaning with carbon dioxide or carbonated water. Since the amount of water is small and the number of times of washing can be reduced, this method is very advantageous in terms of process capability, and can be said to be a method suitable for environmental measures.

According to the present invention, carbon dioxide gas is blown into a closed container or apparatus, and the system is brought into contact with an aqueous solution in which the solubility of carbonic acid is controlled by controlling the pressure and temperature in the system for an appropriate time or more (for example, 5 minutes or more). To change the molecular end of PAS from the basic end (SNa type end) to the acidic end (S
This is a purification method characterized in that the SNa group present at the molecular chain end of the PAS is converted into an SH group, and the affinity with other resins increases.

The solubility of carbon dioxide in water is expressed by the following equation according to Henry's law.

[Calculation formula based on Henry's law] m ₂ = p ₂ / H _{(m) In} (H / H ₀ ) = A (1-T ₀ / T) + Bln (T / T ₀ ) +
C (T / T ₀ -1) m ₂ : mass molar concentration of carbon dioxide gas p ₂ : partial pressure of carbon dioxide gas H _(m) : Henry's constant H ₀ : Henry's constant at 25 ° C. T ₀ : temperature of 25 ° C.

From the above-mentioned calculation formula based on Henry's law, it can be seen that the solubility of carbon dioxide in water increases in proportion to the pressure of carbon dioxide, and conversely decreases as the temperature rises. That is, the solubility of carbon dioxide gas in water is higher at high pressure and low temperature.

However, in consideration of the purification efficiency of PAS, the cost of the apparatus, and the economics of the amount of carbon dioxide used, there are appropriate purification conditions depending on the combination of temperature and pressure. Considering the “paintability” of water and PAS, the higher the temperature at the time of purification, the more preferable. However, if the temperature is increased, the solubility of carbon dioxide gas decreases, which is not preferable.

In the purification conditions of the PAS of the present invention, the preferable range of the pressure condition of the carbon dioxide gas is as high as possible in the range of more than 0.1 MPa and less than 2.0 MPa, more preferably 0.1 MPa. Largely 1.
The pressure is as high as possible in the range of 0 MPa or less.

The preferred range of the temperature condition is 10 to 1
00 ° C, more preferably in the range of 10 to 80 ° C, particularly preferably in the range of 10 to 50 ° C.

When the carbon dioxide or carbonated water of the present invention is contacted with PAS for purification, the solid concentration in the system is 1 to 5
The proportion is preferably 0% by weight. When the solid content is within this range, the contact between the PAS particles and the carbonated water is performed well, and the purification efficiency is suitable and more preferable.

According to the present invention, the contact between carbon dioxide gas or carbonated water and polyarylene sulfide is performed by a closed type or a sealable mixing function having a stirring blade inside the vessel and a filter disposed at the bottom. It can be performed in a container that has.

FIGS. 1, 2 and 3 are schematic diagrams illustrating the introduction of carbon dioxide gas for carrying out the purification method of the present invention, but the present invention is not limited thereto. It is a device having a closed type capable of dissolving carbon dioxide gas in a liquid layer or a device having a mixing function capable of sealing, and may be any device as long as the object of the present invention can be achieved. The devices, lines and substance names shown in FIGS. 1, 2 and 3 are numbered from 1 to 14 and are circled for the sake of explanation.

As described above, the embodiment of the present invention is to remove the crude reaction product containing a polyarylene sulfide obtained by reacting a polyhalo aromatic compound with a sulfidizing agent in an organic polar solvent to remove the solvent. Then, carbon dioxide gas or carbonated water is introduced into the system, and the carbon dioxide gas or carbonated water is brought into contact with the polyarylene sulfide.

In another embodiment of the present invention, crude polyarylene sulfide is obtained after desolvation of a crude reaction product, washed with water, and then carbon dioxide or carbonated water is introduced into the system to obtain a saturated polyarylene sulfide. The present invention relates to the above-mentioned method for purifying polyarylene sulfide, which comprises contacting carbon dioxide or carbonated water with polyarylene sulfide in a state of being pressurized under a vapor pressure.

In another embodiment of the present invention, carbon dioxide or carbonated water is mixed with polyarylene sulfide at 0.1%.
The present invention relates to the above-mentioned method for purifying polyarylene sulfide, wherein the contacting is carried out under a pressure condition of not less than 2.0 MPa and not more than MPa and at a temperature of 10 to 100 ° C.

Another embodiment of the present invention is characterized in that carbon dioxide or carbonated water is brought into contact with polyarylene sulfide in such a manner that the solid concentration in the system becomes 1 to 50% by weight. Of the method for purifying each of the polyarylene sulfides.

According to another aspect of the present invention, a contact between carbon dioxide or carbonated water and polyarylene sulfide is provided by providing a stirring blade inside the vessel and a filter for filtration at the bottom. The present invention relates to a method for purifying each of the above-mentioned polyarylene sulfides, which is carried out in a closed type or a container having a mixing function capable of being closed.

According to another embodiment of the present invention, the crude reaction product is prepared in the presence of a sulfidizing agent and an organic polar solvent.
The present invention relates to the above-mentioned method for purifying each of the polyarylene sulfides, wherein the reaction is performed while continuously or intermittently adding the polyhalo aromatic compound and the organic polar solvent.

Another embodiment of the present invention relates to the above-mentioned method for purifying each polyarylene sulfide wherein the polyhaloaromatic compound is a dihalogenated benzene.

Another embodiment of the present invention relates to the above-mentioned method for purifying each of the polyarylene sulfides, wherein the solvent is removed from the crude reaction product by a distillation apparatus or a solid-liquid separation apparatus. Things.

[0048]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the following, all parts and percentages are by weight unless otherwise specified. The outline of the evaluation method performed in the present invention is as follows.

[Method for Quantifying Terminal Group] PAS10 after drying
g is moistened with a small amount of acetone and dispersed by adding distilled water. Next, an aqueous solution of hydrochloric acid having a concentration of 1 mol / L 10
Add ml and stir. After stirring, the mixture is filtered, and washing with distilled water is repeated until hydrochloric acid is no longer detected (until the aqueous solution of silver nitrate is added and no more cloudy). The obtained polymer is dispersed again in distilled water, and 10 ml of a 1 mol / L aqueous sodium hydroxide solution is added thereto and stirred. After stirring, filtration was carried out, and washing with distilled water was repeated until sodium hydroxide was no longer detected (until the red color disappeared by adding the phenolphthalein solution), and all the filtrate used in the water washing was collected. The sodium is titrated with hydrochloric acid, and the amount of sodium hydroxide consumed is calculated.

[Method for Measuring Isothermal Crystallization Time] Using a differential calorimeter (manufactured by PerkinElmer, model: DSC7),
After holding at 330 ° C. for 3 minutes in a nitrogen atmosphere, the temperature is lowered to 260 ° C. at a rate of 210 ° C./min, and the temperature is held at 260 ° C. It is determined from the time required from the start of holding at 260 ° C. to the peak of the exothermic peak during crystallization.

[Method for Evaluating Reactivity with Epoxysilane-Based Coupling Agent] A PAS containing 0.5% by weight of 3-glycidoxypropyltrimethoxysilane (hereinafter abbreviated as “epoxysilane”) was prepared. A test piece was prepared by injection molding, and the bending elongation at break was measured by a bending tester.

Example 1 A predetermined amount of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), sodium hydrosulfide (concentration analysis value in terms of NaSH = 7) was placed in a pressure-resistant reactor equipped with a stirrer.
2.8% by weight) and a 47.9% by weight aqueous sodium hydroxide solution were charged, and the temperature was raised to 205 ° C. in a nitrogen atmosphere with stirring to obtain a distillate containing water. Next, after closing the nitrogen introduction line and the outflow line and sealing the pressure-resistant reactor, the temperature was raised to 220 ° C., and after reaching 220 ° C., a predetermined amount of NMP solution of p-dichlorobenzene was controlled while generating heat. After completion of the dropping and reaction at 220 ° C. for 3 hours,
The temperature was raised to 255 ° C. over 30 minutes,
After reacting for an hour, the mixture was cooled.

To the crude reaction product of PPS obtained as described above, water of 5 times the weight of PPS contained in the crude reaction product was added and reslurried, and the cake was washed with water of 5 times the weight of PPS. (Filtered substance) The cake (A) was obtained by washing. To the cake (A) was added 5 times the weight of NMP, heated to 120 ° C. and mixed well. The slurry was introduced at this temperature into a centrifugal filter as shown in FIG. Further PP
The cake is washed with NMP 5 times the weight of S. Then, FIG.
As shown in (2), carbon dioxide gas was blown into the pipe, mixed and dissolved well with a static mixer, and PPS was further washed with 7 times the weight of carbonic acid water of PPS to obtain a cake (B).
The pipe pressure at the time of blowing carbon dioxide gas was 0.3 MPa, and the temperature of water was 25 ° C.

The cake (B) is once taken out, reslurried with 5 times the weight of PPS, reslurried, filtered with a centrifugal filter, and further washed with 5 times the weight of PPS to perform solid-liquid separation. After drying the separated PPS, the amount of terminal groups (S
The Na type end group and the SH type end group), the isothermal crystallization time, and the flexural elongation at break with the epoxysilane-based coupling agent were evaluated. The results are shown in Table 1.

Example 2 The cake (A) obtained in Example 1 is subjected to NMP washing in the same manner as in Example 1. Then P
The cake is washed with water 7 times the weight of PS to obtain a cake (C). However, in Example 2, carbon dioxide gas is not dissolved in water used for cake washing. The cake (C) is once taken out, reslurried with 5 times the weight of water, and supplied to the flat plate filter shown in FIG. After the solution was supplied to the flat plate filter, it was treated with carbon dioxide gas.
After pressurizing to 3 MPa and stirring for 30 minutes, the mixture is once filtered. At this time, the temperature of the slurry in the flat plate filter was 25 ° C. The solid-liquid separated cake (D) was treated with P as in Example 1.
After reslurrying with 5 times the weight of PS water and filtering,
The cake was washed with twice the weight of water and dried. Table 1 shows the evaluation results of the obtained PPS.

<< Examples 3 to 5 >> The cake (C) obtained in Example 2 was reslurried with water 5 times the weight of PPS to obtain a slurry (FIG. 3).
Is supplied to the pressure-resistant stirring tank shown in (1). Thereafter, carbon dioxide gas is blown into the pressure-resistant stirring tank, and the pressure in the tank after blowing the carbon dioxide gas is set to 0.11 MPa, followed by stirring for 30 minutes. The slurry temperature in the tank at this time was 25 ° C. Thereafter, the mixture was filtered by a centrifugal separator, washed with 5 times the weight of PPS water to perform solid-liquid separation, and then dried. Table 1 shows the evaluation results of the obtained PPS.

The pressure in the tank after blowing carbon dioxide gas was 0.3 MPa in Example 4 and 1.0 MPa in Example 5.
The operation was performed in the same manner as in Example 3 except that the operation was performed as follows.
Table 1 shows the evaluation results of the obtained PPS.

[0058]

[Table 1]

Comparative Example 1 PPS-containing cake (A) obtained by the same operation as in Example 1 was added to a 5-fold weight of NM.
After adding P and heating to 120 ° C., the mixture was mixed well, and the slurry was introduced into a centrifugal filter at that temperature to perform solid-liquid separation.
Further, the cake is washed with NMP five times the weight of PPS. Thereafter, the PPS is cake-washed with 7 times the weight of PPS water.
The temperature of the water used at this time was 25 ° C. which was the same as that in Example 1 when carbon dioxide was dissolved. Here, the cake (C) was once taken out, reslurried with water 5 times the weight of PPS, filtered with a centrifugal filter, washed with water 5 times the weight of PPS, solid-liquid separated, and dried. P obtained
Table 2 shows the evaluation results of PS.

Comparative Example 2 The cake (C) obtained in Example 2 was once taken out, reslurried with 5 times the weight of water, and fed to a flat plate filter shown in FIG. After supplying the liquid to the flat plate filter, the mixture is pressurized to 0.3 MPa with nitrogen gas, stirred for 30 minutes, and then filtered once. At this time, the temperature of the slurry in the flat plate filter was 25 ° C. The cake (E) subjected to solid-liquid separation was reslurried with 5 times the weight of PPS, filtered, washed with 5 times the weight of PPS, solid-liquid separated and dried in the same manner as in Example 2. Table 2 shows the evaluation results of the obtained PPS.
Shown in

<< Comparative Example 3 >> The cake (C) obtained in Example 2 was once taken out, reslurried with 5 times the weight of water, and then supplied to the flat plate filter shown in FIG. Hydrochloric acid is added to the flat plate filter to adjust the pH of the slurry in the system to 3.0, stirred for 30 minutes, and then filtered once. Then P
The PPS cake is washed with water five times the weight of PS under nitrogen gas pressure to perform solid-liquid separation. At this time, the temperature of the slurry in the flat plate filter was 25 ° C. Solid-liquid separated cake (F)
Is reslurried with 10 times the weight of PPS water and filtered.
The cake was washed with 10 times the weight of S and dried. Table 2 shows the obtained PPS evaluation results.

[0062]

[Table 2]

[0063]

According to the present invention, in a method for purifying polyarylene sulfide (hereinafter abbreviated as PAS),
By bringing carbon dioxide gas into contact with an aqueous solution or carbon dioxide gas that is dissolved under pressure, the reactivity with the epoxysilane-based coupling agent as a compatibilizer is improved, and as a result, the mechanical strength of the molded article is improved. In addition, the crystallization time is shortened, which is effective in improving the productivity at the time of forming. Further, as compared with the conventional refining method using a strong acid, it is possible to reduce the corrosiveness to the production equipment and the mold at the time of molding, and to reduce impurities in the PAS to improve the quality of the PAS. is there. Further, according to the present invention, it is possible to provide a PAS suitable as a material for various molding materials, films, fibers, electric / electronic parts, automobile parts, coatings and the like.

[Brief description of the drawings]

FIG. 1 is an example of a schematic configuration diagram of carbon dioxide gas introduction when the present invention is performed using a centrifugal filter.

FIG. 2 is an example of a schematic configuration diagram of carbon dioxide gas introduction when the present invention is performed using a flat plate filter.

FIG. 3 is an example of a schematic configuration diagram of carbon dioxide gas introduction when the present invention is performed using a pressure-resistant stirring tank. In the drawings, the devices, lines and substance names shown in FIG. 1, FIG. 2 and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Carbon dioxide gas cylinder 2 ... Regulator 3 ... Stirring motor 4 ... Stirring tank 5 ... Stirring blade 6 ... Carbon dioxide dispersion plate 7 ... Pump 8 ... Pressure gauge 9 ... Flow meter 10 ... Statek Mixer 11: Centrifuge 12: Reacted cake (PAS cake) 13: Flat plate filter 14: PAS / water slurry introduction line

Claims (8)

[Claims] 1. A method for removing a crude reaction product containing a polyarylene sulfide obtained by reacting a polyhalo aromatic compound with a sulfidizing agent in an organic polar solvent,
A method for purifying polyarylene sulfide, which comprises introducing carbon dioxide or carbonated water into a system and bringing carbon dioxide or carbonated water into contact with the polyarylene sulfide. 2. After removing the crude reaction product from the solvent, crude polyarylene sulfide is obtained. After washing with water, carbon dioxide or carbonated water is introduced into the system, and carbon dioxide is added under a saturated vapor pressure. The method for purifying polyarylene sulfide according to claim 1, wherein the gas or carbonated water is brought into contact with polyarylene sulfide. 3. The method according to claim 1, wherein carbon dioxide or carbonated water and polyarylene sulfide are brought into contact with each other under a pressure of not less than 0.1 MPa and not more than 2.0 MPa and at a temperature of 10 to 100 ° C. Item 3. The method for purifying polyarylene sulfide according to Item 1 or 2. 4. The method according to claim 1, wherein carbon dioxide or carbonated water and polyarylene sulfide are brought into contact with each other in such a manner that the solid concentration in the system becomes 1 to 50% by weight. A method for purifying polyarylene sulfide. 5. A contact between carbon dioxide gas or carbonated water and polyarylene sulfide, which has a stirring function inside the container and a closed type in which a filter for filtration is provided at the bottom, or a mixing function capable of sealing. The method for purifying polyarylene sulfide according to any one of claims 1 to 4, wherein the method is performed in a vessel. 6. The crude reaction product is reacted while continuously or intermittently adding a polyhalo aromatic compound and an organic polar solvent in the presence of a sulfidizing agent and an organic polar solvent. A method for purifying a polyarylene sulfide according to any one of claims 1 to 5. 7. The method for purifying polyarylene sulfide according to claim 1, wherein the polyhalo aromatic compound is a dihalogenated benzene. 8. The method according to claim 1, wherein the solvent is removed from the crude reaction product by a distillation apparatus or a solid-liquid separation apparatus.
8. The method for purifying polyarylene sulfide according to any one of items 1 to 7, above.