JP3490137B2 - Method for producing polyarylene sulfide - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing polyarylene sulfide (PAS). More specifically, it relates to a method for producing a relatively high molecular weight polyarylene sulfide that is particularly useful in the fields of electricity, electronics, and high rigidity materials.

[0002]

2. Description of the Related Art Polyarylene sulfide resin (PAS
Resin), especially polyphenylene sulfide resin (P
PS resin) has excellent mechanical strength, heat resistance, etc.
It is particularly known as an engineering resin having high rigidity and is useful as a material for electronic / electrical device parts and various high-rigidity materials. Conventionally, the production of these resins has been
Reaction of a dihalogenated aromatic compound such as p-dichlorobenzene with a sodium salt such as sodium sulfide in an aprotic organic solvent such as N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP). The method of allowing has been commonly used. In this case, however, sodium chloride, which is a by-product, is insoluble in a solvent such as NMP, so that it is taken into the resin and it is not easy to remove it by washing.

Therefore, when a lithium salt such as lithium hydroxide is used for the polymerization instead of the sodium salt to produce lithium chloride as a by-product, the lithium chloride is converted into many aprotic organic solvents such as NMP (solvent for polymerization). Since it is soluble in water, it eliminates the need for a water washing step and a waste water treatment step, and is effective as a method for producing high-purity PAS. Therefore, a method using a lithium salt has been in the limelight.

Although various improvements have been made so far with respect to the method for producing PAS using such a lithium salt, the applicant of the present invention also proposed that the present applicant can sulphate lithium N-methylaminobutyrate and sulfide in an aprotic organic solvent. The reaction rate of hydrogen and the dihalogenated aromatic compound was adjusted to 80
A method for producing a relatively high-molecular weight PAS, which is characterized in that prepolymerization is carried out until the amount reaches 99 mol% and then main polymerization is carried out, is proposed (Japanese Patent Application No. 5-32939). This method has an advantage that PAS of high purity and high molecular weight can be easily obtained.

[0005]

However, in this method, when a PAS having a relatively high molecular weight (for example, a solution viscosity of 0.2 or more) is produced, the polymer phase may agglomerate on the stirring blade or the like in the polymerization system. Yes, the polymer may adhere to the stirring blades after cooling, or the extraction line may be blocked when the product is withdrawn, and it is difficult to stably withdraw the polymer when the polymerization system is continuous. In some cases, it was not always satisfactory. The present invention has been made in view of the above problems, and it is possible to easily and smoothly produce a relatively high molecular weight PAS without causing adhesion of a polymer to a stirring blade or the like and blocking of a product extraction line. It is an object to provide a method for producing arylene sulfide.

[0006]

To achieve the above object, according to the present invention, hydroxylation is carried out in an aprotic organic solvent.
In the method for producing a polyarylene sulfide by polymerizing lithium , a liquid or gaseous sulfur compound and a polyhalogenated aromatic compound, the lithium concentration at the time of polymerization is 3 per 1 liter of the aprotic organic solvent. Provided is a method for producing a polyarylene sulfide, which is characterized by controlling the amount to be 6 mol or more.

[0007] In a preferred embodiment thereof, the aprotic organic solvent is N-methyl-2-pyrrolidone, and the method for producing polyarylene sulfide is also the liquid or gaseous sulfur compound. But,
A method for producing polyarylene sulfide, which is hydrogen sulfide, and a method for producing polyarylene sulfide, wherein the polyhalogenated aromatic compound contains paradichlorobenzene in an amount of 50 mol% or more, Further, each of the methods for producing a polyarylene sulfide is provided, wherein the polymerization is a continuous polymerization.

The present invention will be specifically described below. 1. Polymerization raw materials In the method for producing a polyarylene sulfide of the present invention, lithium hydroxide and / or lithium N-methylaminobutyrate, a liquid or gaseous sulfur compound, and a dihalogenated aromatic compound are mixed with an aprotic organic solvent. Polymerize inside.

(1) Aprotic organic solvent The aprotic organic solvent used in the present invention is generally an aprotic polar organic compound (eg, amide compound, lactam compound, urea compound, organic sulfur compound, ring). Formula organophosphorus compounds, etc.) can be suitably used as a single solvent or as a mixed solvent.

Of these aprotic polar organic compounds, examples of the amide compound include N, N-
Dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dipropylacetamide, N,
Examples thereof include N-dimethylbenzoic acid amide.

Examples of the lactam compound include caprolactam, N-methylcaprolactam, N
-N-alkylcaprolactams such as -ethylcaprolactam, N-isopropylcaprolactam, N-isobutylcaprolactam, N-normalpropylcaprolactam, N-normalbutylcaprolactam, N-cyclohexylcaprolactam, N-methyl-2-pyrrolidone (NMP), N -Ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-normal propyl-2-pyrrolidone, N-normal butyl-2-pyrrolidone, N-cyclohexyl-
2-pyrrolidone, N-methyl-3-methyl-2-pyrrolidone, N-ethyl-3-methyl-2-pyrrolidone, N-
Methyl-3,4,5-trimethyl-2-pyrrolidone, N
-Methyl-2-piperidone, N-ethyl-2-piperidone, N-isopropyl-2-piperidone, N-methyl-
6-methyl-2-piperidone, N-methyl-3-ethyl-2-piperidone and the like can be mentioned.

Examples of the urea compound include tetramethylurea, N, N'-dimethylethyleneurea, N, N'-dimethylpropyleneurea and the like.

Further, as the organic sulfur compound,
For example, dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfone, 1-methyl-1-oxosulfolane, 1-ethyl-1-oxosulfolane, 1-phenyl-1-oxosulfolane, and the like as the cyclic organic phosphorus compound. Examples thereof include 1-methyl-1-oxophosphorane, 1-normalpropyl-1-oxophosphorane, 1-phenyl-1-oxophosphorane and the like.

These various aprotic polar organic compounds may be used alone or in combination of two or more,
Furthermore, it can be used as the aprotic organic solvent by mixing with other solvent components which do not hinder the purpose of the present invention.

Among the above various aprotic polar organic solvents, N-alkylcaprolactam and N are preferable.
-Alkylpyrrolidone, particularly preferred is N-methyl-2-pyrrolidone.

(2) Lithium hydroxide and / or N-
Lithium methylaminobutyrate Lithium hydroxide and / or N- used in the present invention
There is no particular limitation on lithium methylaminobutyrate,
A commercially available product can be used as long as it has high purity.
As the lithium N-methylaminobutyrate, those produced by the production method previously proposed by the applicant in Japanese Patent Application No. 4-183717 are preferable. That is, first, in an aprotic organic solvent, N-methyl-2-pyrrolidone is reacted with an alkali metal hydroxide except lithium to form an alkali metal salt of N-methylaminobutyric acid (that is, N-methyl). Alkali metal salts of aminobutyric acid other than lithium) are synthesized.

Next, other than lithium N-methylaminobutyric acid such as sodium N-methylaminobutyrate obtained by synthesis of an alkali metal salt other than lithium N-methylaminobutyric acid such as sodium N-methylaminobutyrate. Water is removed from the reaction mixture containing the alkali metal salt to reduce the water concentration. This water removal step can be performed according to a conventional method such as distillation. At that time, a part of the organic solvent may be removed. The synthesized alkali metal salt of N-methylaminobutyric acid such as sodium N-methylaminobutyric acid other than lithium can be isolated once and used as a raw material in the next step. From the viewpoint of the process, it is advantageous to subject the reaction mixture of (1) to the next reaction step as it is, or to the extent that the amount of the solvent is appropriately adjusted as necessary.

Next to the above, N such as sodium N-methylaminobutyrate whose water concentration was reduced in the water removing step is used.
-By contacting a solution of an alkali metal salt of methylaminobutyric acid other than lithium with lithium chloride, the N-
An alkali metal salt of methylaminobutyric acid other than lithium is reacted with lithium chloride to synthesize desired lithium N-methylaminobutyrate. At that time, a chloride of an alkali metal component of the alkali metal salt of N-methylaminobutyric acid such as sodium N-methylaminobutyric acid used other than lithium (that is, an alkali metal component other than lithium) is by-produced. By-product alkali metal chloride is removed to obtain a solution of the desired lithium N-methylaminobutyrate in which alkali metal components other than lithium are completely or sufficiently removed.

In the present invention, both lithium hydroxide and lithium N-methylaminobutyrate may be used,
Also, only one of them may be used.

(3) Liquid or Gaseous Sulfur Compound The liquid or gaseous sulfur compound used in the present invention is not particularly limited, but hydrogen sulfide can be preferably used.

(4) Polyhalogenated Aromatic Compound The polyhalogenated aromatic compound used in the present invention is not particularly limited, and examples thereof include aromatic compounds having two or more halogen atoms in one molecule. A known compound used for the production of polyarylene sulfide can be specifically mentioned as a preferable example.

For example, m-dihalogenbenzene, p-
Dihalogenbenzenes such as dihalogenbenzene; 2,3
-Dihalogentoluene, 2,5-dihalogentoluene,
2,6-dihalogentoluene, 3,4-dihalogentoluene, 2,5-dihalogenxylene, 1-ethyl-2,
Alkyl-substituted dihalogens such as 5-dihalogenbenzene, 1,2,4,5-tetramethyl-3,6-dihalogenbenzene, 1-normalhexyl-2,5-dihalogenbenzene, 1-cyclohexyl-2,5-dihalogenbenzene Benzene or cycloalkyl-substituted dihalogenbenzenes; 1-phenyl-2,5-dihalogenbenzene, 1-benzyl-2,5-dihalogenbenzene, 1-
Aryl-substituted dihalogenbenzenes such as p-toluyl-2,5-dihalogenbenzene; dihalobiphenyls such as 4,4′-dihalobiphenyl: 1,4-dihalonaphthalene, 1,6-dihalonaphthalene, 2 And dihalonaphthalene such as 6-dihalonaphthalene.

The two halogen elements in these dihalogenated aromatic compounds are respectively fluorine, chlorine, bromine or iodine, which may be the same,
They may be different from each other.

Of these, dihalogenbenzenes are preferable, and those containing p-dichlorobenzene in an amount of 50 mol% or more are particularly preferable.

(5) Usage ratio The usage ratio (lithium concentration) of lithium at the time of polymerization is controlled by adjusting the charged amounts of the lithium compound and the solvent so that the amount is 3.6 mol or more per liter of the aprotic organic solvent. Do it. When the amount is 3.6 mol / liter or more, stable dispersion (the polymer phase is dispersed in the form of droplets) can be obtained. If it is less than 3.6 mol / liter, the polymer phase may become lumpy and adhere to the stirring blade and the like. When hydrogen sulfide is used as the sulfur compound,
The usage ratio of lithium hydroxide and / or lithium N-methylaminobutyrate (molar ratio: lithium hydroxide and / or lithium N-methylaminobutyrate / hydrogen sulfide) is usually 1.80 to 3.00, particularly 1.95. ˜3.00. Lithium hydroxide and / or N for hydrogen sulfide
-When the usage ratio of lithium methylaminobutyrate is within the above range, the polymerization reaction proceeds more smoothly.

Similarly, the use ratio of hydrogen sulfide to polyhalogenated aromatic compound (molar ratio: hydrogen sulfide / dihalogenated aromatic compound) is usually 0.90 to 1.30, particularly 0.95 to 1.25. Is. When the ratio of hydrogen sulfide to the polyhalogenated aromatic compound is within the above range, the polymerization reaction will proceed more smoothly.

Similarly, the use ratio of hydrogen sulfide to the aprotic organic solvent (molar ratio: hydrogen sulfide / aprotic organic solvent) is usually 0.05 to 0.30, particularly 0.05 to.
It is 0.25. In addition, when the lithium N-methylaminobutyrate is used, the amount of this aprotic organic solvent is the amount of the aprotic organic solvent charged and the amount of non-protonic organic solvent produced by the reaction of this lithium N-methylaminobutyrate and hydrogen sulfide. It is the total amount with the amount of the protic organic solvent. When the use ratio of hydrogen sulfide to the aprotic organic solvent is within the above range, the polymerization reaction proceeds smoothly, and it becomes suitable for continuous polymerization.

In the present invention, if necessary, active hydrogen-containing halogenated aromatic compounds, polyhalogenated aromatic compounds having 3 or more halogen atoms in one molecule, halogenated aromatic nitro compounds, etc. A branching agent can be used by appropriately selecting it and adding it to the reaction system.

The proportion of the branching agent used, if necessary, is usually 0.000 with respect to 1 mol of the hydrogen sulfide.
It is 5 to 0.05 mol, preferably 0.001 to 0.02 mol.

2. Polymerization operation In the present invention, in the aprotic organic solvent,
Lithium hydroxide and / or lithium N-methylaminobutyrate, a liquid or gaseous sulfur compound, and a polyhalogenated aromatic compound are polycondensed while controlling the use ratio of lithium to the aprotic organic solvent. Produces polyarylene sulfide. Hereinafter, the present invention will be described in the order of each step.

(1) Charge step In this step, hydrogen sulfide, lithium hydroxide and / or lithium N-methylaminobutyrate, polyhalogenated aromatic compound and aprotic organic solvent are charged into, for example, a polymerization reactor. The amount of each component charged is within the range of the above-mentioned usage ratio.

Although there is no particular limitation on the order of addition of the components when the components are charged, the following three methods can be mentioned as suitable examples of the charge formulation.

First, lithium hydroxide and / or N
An aprotic organic solvent solution of lithium methylaminobutyrate and a dihalogenated aromatic compound is prepared, and hydrogen sulfide is blown into the aprotic organic solvent solution to dissolve it.

An aprotic solvent solution in which hydrogen sulfide has been previously blown and dissolved therein is mixed with lithium hydroxide and / or lithium N-methylaminobutyrate and the polyhalogenated aromatic compound.

Hydrogen sulfide is blown into and dissolved in a solution of lithium hydroxide and / or lithium N-methylaminobutyrate in an aprotic organic solvent, and then a polyhalogenated aromatic compound is added.

The temperature of the system at the time of introducing (blowing) the liquid or gaseous sulfur compound is usually room temperature, but preferably less than 170 ° C. More preferably, it is less than 150 ° C, and most preferably less than 130 ° C. 1
When the temperature is 50 ° C. or higher, solid sulfide may be precipitated.

When hydrogen sulfide is used, the pressure at which it is blown may be atmospheric pressure or increased pressure. The blowing time is not particularly limited and is usually preferably about 10 to 180 minutes. The blowing speed is also not particularly limited, and normally it is preferably about 10 to 1000 cc / min.

(2) Complex Synthesis Step In this step, a complex is synthesized from lithium hydroxide and / or lithium N-methylaminobutyrate and hydrogen sulfide.

As synthesis conditions, the temperature is 100 to 200 ° C.
And is preferably 130 to 150 ° C. In this temperature range, the reaction system is left standing or stirred for 10 minutes to 5 hours, preferably 1 hour to 2 hours. Under such synthetic conditions, the above complex is particularly preferably formed.

(3) Prepolymerization Step In the present invention, lithium hydroxide and / or lithium N-methylaminobutyrate, hydrogen sulfide, and a polyhalogenated aromatic compound are optionally used in an aprotic organic solvent. The prepolymerization is preferably carried out so that the reaction rate of the polyhalogenated aromatic compound becomes 80 to 99%, preferably 80 to 95%.

Efficiently producing a polyarylene sulfide having a solution viscosity of 0.20 or more by carrying out prepolymerization so that the reaction rate of the polyhalogenated aromatic compound becomes the above ratio and then carrying out the polymerization described later. You can If the reaction rate of the polyhalogenated aromatic compound is less than 80%, it may not be possible to produce a high molecular weight polyarylene sulfide.

The reaction rate of the polyhalogenated aromatic compound in this prepolymerization is the same as that of the polyhalogenated aromatic compound charged with the amount of the polyhalogenated aromatic compound distilled during the dehydration step after the prepolymerization step. It can be calculated from the value subtracted from the amount, and if dehydration is not performed,
It can be determined from the value obtained by subtracting the amount of the polyhalogenated aromatic compound in the reaction solution after the prepolymerization from the amount of the charged polyhalogenated aromatic compound. The quantitative analysis of the polyhalogenated aromatic compound can be carried out by gas chromatography analysis of the polyhalogenated aromatic compound in the distillate when dehydration is carried out and in the reaction liquid when dehydration is not carried out.

(4) Dehydration Step In the present invention, when a higher molecular weight polyarylene sulfide is to be produced, it is preferable to employ a dehydration step if necessary. The dehydration step may be performed between the complex synthesis step and the preliminary polymerization step, may be performed between the preliminary polymerization step and the polymerization step, and may be performed between the complex synthesis step and the preliminary polymerization step and between the preliminary polymerization step and the polymerization step. It may be both during the process.

As the dehydration condition, the temperature is usually 50 to 50.
180 ° C., preferably 130 to 160 ° C. The pressure may be reduced pressure or increased pressure, usually 1 mmHg
It is appropriately selected from the range of 10 kg / cm ² .
As the dehydrating atmosphere, an inert gas atmosphere such as a nitrogen gas atmosphere is usually adopted.

The degree of dehydration is 70% or more, preferably 80% or more of the water content relative to the water content produced when the reaction proceeds 100%, preferably over 1 to 2 hours. Is good. By dehydrating until 70% or more of water is distilled off, a high molecular weight polyarylene sulfide can be produced more reliably.

The amount of dehydration can be confirmed by quantifying the water content in the distillate by gas chromatography analysis.

(5) Polymerization Step In this step, first, if necessary, it is preferable to adjust the sulfur content from the reaction solution obtained in the dehydration step by a desulfurization operation, for example, a desulfurization operation. That is, in order to carry out the reaction of the polyhalogenated aromatic compound described later, the ratio of sulfur / lithium present in the system is 1 /
It is preferably 2 (S atom / Li atom molar ratio) or less, and more preferably controlled to 1/2.
If it is larger than 1/2, the reaction is difficult to proceed, so PAS
It becomes difficult to produce resin. The control method is not particularly limited, but, for example, a sulfur compound blown to separate an alkali metal chloride or an alkaline earth metal chloride, for example, hydrogen sulfide, is used as an alkali metal chloride or an alkaline earth metal chloride. After separation of the above, the total amount of sulfur present in the system can be adjusted by subjecting the liquid portion in the system to nitrogen bubbling or the like to remove. In this case, you may heat. In addition, lithium hydroxide and N-
It may be controlled by adding a lithium salt such as lithium methylaminobutyrate (LMAB) into the system.

The polymerization step is carried out after the preliminary polymerization step, or after the dehydration step, which is carried out as necessary after the completion of the preliminary polymerization step or the like.

As the reaction vessel, for example, a 1-liter stainless steel autoclave (a paddle blade is provided as a stirring blade and the rotation speed is 300 to 700 rpm) can be mentioned. The polymerization temperature is preferably 230 to 280 ° C., and the polymerization time is preferably 0.1 to 10 hours.
The amount of the polyhalogenated aromatic compound added is preferably selected from the range of polyhalogenated aromatic compound / sulfur existing in the system = 0.9 to 1.3 (molar ratio), as described above, 0.95-1.25 is more preferable.

(6) Post-Treatment Step The polyarylene sulfide synthesized by the above-mentioned polymerization reaction is directly separated from the reaction vessel by a standard method such as filtration or centrifugation, or
For example, it can be isolated by adding a coagulating liquid such as water and / or a diluted acid and then separating from the reaction solution.

The isolated polymer is usually treated with water or NM in order to remove adhering impurities or by-products.
It is desirable to wash with a washing solvent such as P, methanol, acetone, benzene, or toluene.

Even without isolation, the polymer can be obtained by distilling the solvent from the reaction solution to recover it, and washing the residue as described above. The recovered solvent can be reused.

In the method of the present invention, as described above, the solution viscosity (η _inh ) is 0.20 or more and the melt index (MI) is 0 to 1,000 g / 10 minutes. Granulated polyarylene sulfides of high molecular weight, in some cases gel-forming and having a particle size of 0.5 to 5 mm, with controlled particle size, are subjected to a simplified process. It can be easily and stably obtained. It should be noted that the term "granular" according to the present invention usually means a granular shape, but may be a bead shape. Further, the solution viscosity is obtained by dissolving granular polyarylene sulfide in α-chlornaphthalene to a concentration of 0.4 g / dl,
It is a value measured using an Ubbelohde viscometer at a temperature of 06 ° C.

Further, in order to recover Li ions existing as LiCl in the reaction solution, alkali metal hydroxides and alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide and water are used in the system. Magnesium oxide or the like may be added. Of these, sodium hydroxide is preferred.
The amount of the hydroxyl group added is 0.90 to 1.1 mol, preferably 0.95 to 1.05, relative to 1 mol of lithium ion.
Try to be mol. If the amount exceeds 1.1 mol, it does not hinder the production of lithium hydroxide, but the purity of the produced PAS is decreased due to the increase of the basic unit of alkali metal (earth metal) hydroxide and the subsequent operation. It is not preferable because it may lead to. On the other hand, when it is less than 0.90, lithium remains dissolved as chloride, resulting in loss of lithium. The reaction temperature in this case is not particularly limited, but when the alkali metal hydroxide or the alkaline earth metal hydroxide is charged in the form of an aqueous solution, it is usually room temperature to 230 ° C, preferably 65 to 150 ° C.
When the solid state is charged, it is usually 60 to 230.
C., preferably 90 to 150.degree. When the reaction temperature is low, the solubility is low and the reaction rate is remarkably slow. When the reaction temperature is high, it becomes higher than the boiling point of NMP, and it has to be carried out under pressure, which is a process disadvantage. The reaction time is not particularly limited.

The polyarylene sulfide thus obtained may be subjected to various desalting treatments, if necessary, to further reduce the salt content such as lithium chloride in the polymer.

When various products are molded from the polyarylene sulfide obtained by the present invention, other polymers, pigments, graphite, metal powder, glass powder, quartz powder, talc may be added to the polyarylene sulfide as required. , Calcium carbonate, glass fiber, carbon fiber, various whiskers and other fillers, stabilizers, release agents and the like can be appropriately mixed.

The polyarylene sulfide obtained according to the present invention can be suitably used as a material for various molded products such as films, fibers, mechanical parts, electric parts and electronic parts.

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

EXAMPLES The present invention will be described in more detail below with reference to Examples.
Explained. (1) When using lithium hydroxide (LiOH) (i) Lithium hydroxide manufactured by Kanto Chemical Co., Inc. having a purity of 98% was used. ( Ii ) Synthesis of hydrogen sulfide-Li complex In a 500 ml glass separable flask equipped with a stirring blade, 41.94 g (4.2 mol) of N-methyl-2-pyrrolidone and the above-mentioned (i) anhydrous lithium hydroxide 36. 79 g
(1.5 mol) and 27.0 g (1.5 mol) of deionized water were added and the temperature was raised to 130 ° C. After heating, add 7
00 ml / min. It was blown into the liquid for 35 minutes at a feeding rate of. The liquid temperature during the blowing of hydrogen sulfide was controlled so as to always maintain 130 ° C. The supply of hydrogen sulfide was stopped, and S in the liquid
As a result of quantifying the amount of (sulfur), 1.182 mol was absorbed, and thus the S / Li ratio (molar ratio) = 0.79.
In addition, some outflow of NMP was observed during the synthesis of the complex. As a result of analyzing the obtained complex, S and L per 1 g of the complex were analyzed.
The amounts of i and NMP were S: 2.938 × 10 ⁻³ (mol / gram), Li: 3.730 × 10 ⁻³ (mol / gram), and NMP: 0.8771 (gram / gram), respectively.
Met.

Example 1 In a 0.3 liter glass autoclave equipped with a stirring blade, 22.06 g of N-methyl-2-pyrrolidone (0.
222 mol), p-dichlorobenzene 22.05 g
(0.150 mol), the complex 51. synthesized in ( ii ) above.
05 g (0.15 mol), 2.87 g (0.117 mol ) of anhydrous lithium hydroxide of the above (i ), and 0.408 g (0.0022 mol) of trichlorobenzene were added, and the mixture was heated to 240 ° C. in a closed system. While stirring for 30 minutes, prepolymerization was performed. Then, the temperature was raised to 260 ° C., and polymerization was carried out for 3 hours while maintaining 260 ° C. In this case, the lithium concentration (Li / NMP) was 4.74 mol / liter. Observation of the dispersed state during the polymerization revealed that the polymer phase was uniformly dispersed in the form of droplets. After the completion of the polymerization reaction, the reaction system was cooled, the obtained solid content was washed successively with water and acetone, and dried to obtain 15.32 g of polyarylene sulfide (yield 93.5%). The obtained polyarylene sulfide was added to α-chlornaphthalene in an amount of 0.
It melt | dissolved so that it might become a density | concentration of 4 g / dl, and the viscosity was measured using the Ubbelohde viscometer at the temperature of 206 degreeC. As a result, the solution viscosity of this polyarylene sulfide η _inh
Was infinite.

[ Comparative Example 1 ] N-methyl-2-pyrrolidone as a raw material for polymerization: 39.9
2 g (0.403 mol), p-dichlorobenzene: 1
7.28 g (0.118 mol), the complex synthesized in ( ii ) above: 40 g (0.118 mol), and anhydrous lithium hydroxide in (i) above: 2.20 g ( 0.090 mol) were prepared. . The same operation as in Example 1 was performed using the above raw materials. In this case, the lithium concentration (Li / NMP) is 3.
It was 28 mol / liter. As a result, 13.71 g (yield 89.3%) of polyarylene sulfide was obtained.
In this case, in the dispersed state during the polymerization, the polymer phase was lumpy. When the solution viscosity η _inh of the obtained polyarylene sulfide was measured by the same operation as in Example 1, it was 0.
It was 345.

[0068]

[Table 1]

[0070]

[0071]

[0072]

[0073]

As described above, according to the method for producing a polyarylene sulfide of the present invention, it is possible to stabilize the dispersion of the polymer phase by controlling the lithium concentration (Li / NMP) in the polymerization system, and to produce PAS. Preventing polymer from adhering to blades, baffles, etc. in the process It became possible to prevent clogging during withdrawal of the reaction liquid.

[Brief description of drawings]

FIG. 1 is a flow chart schematically showing a production process of a polyarylene sulfide of the present invention and a dispersed state during polymerization.

Claims (5)

(57) [Claims] 1. A lithium hydroxide in an aprotic organic solvent.
In the method for producing polyarylene sulfide by polymerizing thium , a liquid or gaseous sulfur compound and a polyhalogenated aromatic compound, the lithium concentration at the time of polymerization is set to 3 per 1 liter of the aprotic organic solvent.
A method for producing a polyarylene sulfide, which is controlled to 6 mol or more. 2. The method for producing a polyarylene sulfide according to claim 1, wherein the aprotic organic solvent is N-methyl-2-pyrrolidone. 3. The liquid or gaseous sulfur compound is hydrogen sulfide.
A method for producing the described polyarylene sulfide. 4. The method for producing a polyarylene sulfide according to claim 1, wherein the polyhalogenated aromatic compound contains 50 mol% or more of paradichlorobenzene. 5. The method for producing polyarylene sulfide according to claim 1, wherein the polymerization is continuous polymerization.