JP2002284876A - Manufacturing method of polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently manufacturing in a short time a high-molecular weight PAS reduced in the oligomer content. SOLUTION: In a method for manufacturing a polyarylene sulfide by reacting a polyhalogenated aromatic compound with a sulfidizing agent in an organic polar solvent at a temperature of at least 200 deg.C and lower than 290 deg.C, the reaction above comprises at least the following steps 1 and 2, step 1: a step for forming a prepolymer of a polyarylene sulfide by reacting a polyhalogenated aromatic compound with a sulfidizing agent at a molar ratio of the solvent to the charged sulfidizing agent of at least 3.5 and at most 10.0, and step 2: a step for converting the prepolymer into the high-molecular weight polyarylene sulfide in the presence of a polymerization auxiliary by adjusting the molar ratio of the solvent to the charged sulfidizing agent to at least 1.5 and less than 3.5.

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 (hereinafter sometimes abbreviated as PAS), and more particularly, to a method for efficiently producing a high molecular weight PAS having a reduced oligomer content in a short time. It relates to a manufacturing method.

[0002]

2. Description of the Related Art PAS has heat resistance, chemical resistance, flame retardancy,
It is an engineering plastic with excellent mechanical strength, electrical properties, dimensional stability, etc., and various molded products by various molding methods such as injection molding, extrusion molding and compression molding.
Because it can be formed into films, sheets, fibers, etc.
It is widely used in a wide range of fields such as electric / electronic equipment and automobile equipment.

As a method for producing PAS, Japanese Patent Publication No. 45-3
No. 368 proposes a method in which an alkali metal sulfide such as sodium sulfide and a polyhalo aromatic compound such as p-dichlorobenzene are reacted in an organic amide solvent such as N-methyl-2-pyrrolidone. However, in this method, since the amount of solvent used is constant throughout the polymerization reaction and no polymerization aid is used, only PAS having a high oligomer content and a low molecular weight and a low melt viscosity can be obtained. Such a low molecular weight PAS can be made high molecular weight by heating in the presence of air after polymerization and oxidatively curing (curing), but the cured PAS thus obtained has poor mechanical properties. Since it is sufficient and not linear, it has been difficult to form into a sheet, film, fiber or the like.

[0004] After that, in order to obtain a PAS having a high molecular weight during polymerization, various production methods improved from the above method have been proposed. As means for improving the polymerization method of PAS,
When reacting an alkali metal sulfide with a polyhalo aromatic compound in an organic amide solvent, a typical method is to add various polymerization aids, for example, a method using an alkali metal carboxylate as a polymerization aid (Section 52-1
2240), a method using an alkaline earth metal of an aromatic carboxylic acid (JP-A-59-219332), and a method using an alkali metal halide (US Pat. No. 4,038,263). ), And a method using a sodium salt of an aliphatic carboxylic acid (Japanese Patent Application Laid-Open No. 1-161022).

According to these methods, it is possible to obtain a linear and high molecular weight PAS by polymerization, but since the amount of solvent used is constant throughout the reaction, the oligomer content is reduced as in the present invention. It was not possible to efficiently produce a high-molecular-weight PAS in a short time. further,
In order to obtain a higher molecular weight PAS, it is necessary to carry out polymerization using an expensive polymerization aid such as lithium acetate or sodium benzoate, and if an inexpensive polymerization aid such as sodium acetate is simply applied. However, there is a problem that the polymerization time is long, which is economically disadvantageous, and that the degree of polymerization is limited.

[0006] Further, when PAS is produced by the method exemplified above, low molecular weight PAS is simultaneously produced as a by-product. In general, these low molecular weight components cause a decrease in mechanical performance such as bending strength of a product, an increase in the amount of gas generated when a resin is melted, and an increase in stains on a mold and a die during molding. , Usually through several purification steps, separation,
Although they are removed, these steps require a long time, which lowers productivity and increases costs.

[0007] Regarding the reduction of such low molecular weight components,
Japanese Patent Application Laid-Open No. 5-230214 discloses a method of performing polymerization by removing a part of a solvent during the reaction. There is still a significant amount of low molecular weight components. Further, there has been a problem that a considerably long polymerization time is required to obtain a PAS having a sufficiently high molecular weight, and there is a limit in increasing the degree of polymerization.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to improve the drawbacks of the prior art and to efficiently obtain a high-molecular-weight PAS having a reduced oligomer content in the production of a PAS in a short time. It was achieved as a result of the examination.

[0009]

In order to achieve the above object, the polyarylene sulfide resin of the present invention is obtained by the following method. That is, the present invention provides: In a method for producing a polyarylene sulfide by reacting a sulfidizing agent and a polyhalogenated aromatic compound in an organic polar solvent within a temperature range of 200 ° C. or more and less than 290 ° C., the above reaction is carried out in at least the following steps 1 and 2. A method for producing a polyarylene sulfide, which is carried out according to Step 2, wherein the molar ratio of the solvent to the charged sulfide agent is from 3.5 or more to 10.0 or less, and the polyhalogenated aromatic compound and the sulfide agent are To produce a prepolymer of polyarylene sulfide, and Step 2: in the presence of a polymerization aid, the molar ratio of the solvent to the sulfidizing agent charged is 1.5 or more and less than 3.5, and the prepolymer is 1. Step of converting to high molecular weight polyarylene sulfide 2. The method for producing a polyarylene sulfide according to claim 1, wherein the step 1 is performed in a temperature range from 200 ° C. to less than 245 ° C., and the step 2 is performed in a temperature range from 245 ° C. to less than 290 ° C. 3. , 3. 3. The method for producing a polyarylene sulfide according to the above 1 or 2, wherein the reaction is carried out so that the conversion of the polyhalogenated aromatic compound becomes 85% or more in the step 1, and then the step 2 is carried out. , 4. The polypolymer according to any one of the above items 1 to 3, wherein the total polymerization time in which the system temperature including the constant temperature time, the temperature rising time and the temperature falling time is 200 ° C or more is 3 to 10 hours. 4. A method for producing an arylene sulfide; At least the step 2 is selected from an organic carboxylate, water, an alkali metal chloride, an organic sulfonate, an alkali metal sulfate, an alkaline earth metal oxide, an alkali metal phosphate, and an alkaline earth metal phosphate. 5. The method for producing a polyarylene sulfide resin according to any one of the above items 1 to 4, wherein the method is carried out in the presence of at least one polymerization aid; After the completion of the reaction in Step 1, the obtained reaction mixture is subjected to Step 1
6. The method according to any one of the above items 1 to 5, wherein the reaction vessel is transferred to a reaction vessel different from the reaction vessel in which the
The method for producing a polyarylene sulfide resin described in the above section.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyarylene sulfide in the present invention is a homopolymer or a copolymer having a repeating unit of the formula-(Ar-S)-as a main constituent unit.
Examples of Ar include units represented by the following formulas (A) to (K), and among them, (A) is particularly preferable.

[0011]

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(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.) It may contain a small amount of a branching unit or a crosslinking unit represented by the following formulas (L) to (N). The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0 to 1 mol% based on 1 mol of-(Ar-S) -unit.

[0013]

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Further, the polyarylene sulfide in the present invention may be a random copolymer, a block copolymer or a mixture thereof containing the above repeating unit.

Further, the molecular weight of the various polyarylene sulfides is not particularly limited, but usually has a melt viscosity of 5 to 5.
5,000 Pa · s (310 ° C., shear rate 1,000 /
Seconds) can be exemplified as a preferable range.

As typical examples thereof, polyphenylene sulfide, polyphenylene sulfide sulfone,
Examples include polyphenylene sulfide ketone, random copolymers thereof, block copolymers, and mixtures thereof. Particularly preferred polyarylene sulfides include a p-phenylene unit as a main structural unit of the polymer.

[0017]

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, Polyphenylene sulfide, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone containing 90 mol% or more.

Sulfidizing agent The sulfidizing agent used in the present invention includes alkali metal sulfides and alkali metal hydrosulfides.
Specific examples of the alkali metal sulfide include, for example, lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more of these. Among them, sodium sulfide is preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Specific examples of the alkali metal hydrosulfide include:
For example, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and these two
Mixtures of more than one species can be mentioned as preferable ones, and among them, sodium hydrosulfide is preferably used.
These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Further, an alkali metal sulfide prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Further, an alkali metal sulfide can be prepared from an alkali metal hydrosulfide and an alkali metal hydroxide, and the obtained reaction mixture can be transferred to a reaction vessel in the next step and used.

Alternatively, an alkali metal sulfide prepared in situ from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide in a reaction system can be used. Alternatively, an alkali metal sulfide can be prepared from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide, and the resulting reaction mixture can be transferred to a reaction vessel in the next step and used.

In the present invention, when a part of the sulfidizing agent is lost before the start of the polymerization reaction due to dehydration operation or the like, the amount of the charged sulfidizing agent is determined by subtracting the loss from the actual charged amount. Shall mean.

It is also possible to use an alkali metal hydroxide and / or an alkaline earth metal hydroxide together with the sulfidizing agent. Specific examples of the alkali metal hydroxide, for example, sodium hydroxide, potassium hydroxide,
Lithium hydroxide, rubidium hydroxide, cesium hydroxide and a mixture of two or more thereof can be mentioned as preferable examples. Specific examples of the alkaline earth metal hydroxide include, for example, calcium hydroxide, strontium hydroxide,
Barium hydroxide and the like can be mentioned, and among them, sodium hydroxide is preferably used.

When an alkali metal hydrosulfide is used as the sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide at the same time. .20 mol, preferably 1.00 to 1.15 mol, more preferably 1.
The range of 005 to 1.100 mol can be exemplified.

Polyhalogenated aromatic compound The polyhalogenated aromatic compound used in the present invention is:
A compound having two or more halogen atoms in one molecule. Specific examples include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene,
1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4
-Diiodobenzene, 1,4-dichloronaphthalene,
1,5-dichloronaphthalene, 1-methoxy-2,5-
Dichlorobenzene, 4,4′-dichlorobiphenyl,
Polyhalogenated aromatic compounds such as 3,5-dichlorobenzoic acid, 4,4'-dichlorodiphenylether, 4,4'-dichlorodiphenylsulfone, and 4,4'-dichlorodiphenylketone are exemplified. Chlorobenzene, 4,4'-dichlorodiphenylsulfone and 4,4'-dichlorodiphenylketone are used, more preferably p-dichlorobenzene. It is also possible to combine two or more different polyhalogenated aromatic compounds into a copolymer, but it is preferable to use a p-dihalogenated aromatic compound as a main component.

The amount of the polyhalogenated aromatic compound used is
From the viewpoint of obtaining a polyarylene sulfide having a viscosity suitable for processing, 0.9 to 2.0 mol, preferably 0.95 to 1.5 mol, more preferably 1.005 to 1.2 mol per mol of the sulfidizing agent. The range of moles can be exemplified.

Molecular weight regulator, branching / crosslinking agent In the present invention, the terminal of the formed PAS is
Alternatively, a monohalogen compound (not necessarily an aromatic compound) can be used in combination with the polyhalogenated aromatic compound for the purpose of controlling the polymerization reaction or the molecular weight. Further, in order to form a branched or crosslinked polymer, a polyhalogenated compound (not necessarily an aromatic compound), an active hydrogen-containing halogenated aromatic compound, a halogenated aromatic nitro compound, etc. are used in combination. It is also possible.

Polymerization Solvent In the present invention, an organic polar solvent is used as a polymerization solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone;
-Caprolactams such as -methyl-ε-caprolactam, 1,3-dimethyl-2-imidazolidinone, N, N
-Aprotic organic solvents represented by -dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, dimethylsulfone, tetramethylenesulfoxide and the like, and mixtures thereof are preferably used because of high reaction stability. You. Among them, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) is preferably used.

The amount of the organic polar solvent used is such that the amount of the organic polar solvent in the reaction system is from 3.5 mol to 10 mol per mol of the sulfidizing agent at the start of the polymerization reaction in the step 1 for producing the prepolymer. Moles, preferably 3.8 to 8.0 moles, more preferably 4.0 to 6.5 moles. If the amount is too small, an undesirable reaction tends to occur. If the amount is too large, the degree of polymerization tends to hardly increase. If the amount is too large or too small, the time required for the reaction becomes long, which is economically disadvantageous. Here, the amount of the organic polar solvent in the reaction system is an amount obtained by subtracting the amount of the organic polar solvent removed outside the reaction system from the amount of the organic polar solvent introduced into the reaction system.

In order to efficiently produce a high-molecular-weight PAS having a reduced oligomer content in a short time by the method of the present invention, the above-mentioned sulfidizing agent and polyhalogenated aromatic compound are combined with an organic polar solvent. In the process of reacting inside, it is necessary to exclude such a solvent out of the reaction system and reduce the amount of the solvent.

In the present invention, specific methods for reducing the amount of solvent include a method of removing the solvent by distillation, a method of removing the solvent by filtration, a method of removing the solvent by flash transfer, and an affinity with the solvent. Examples of the method include adding a substance having a strong characteristic to cause phase separation and substantially removing the solvent outside the reaction system. However, distillation is preferred from the viewpoint of simplicity of operation. Further, after the solvent is removed, by continuing the reaction at the same temperature or higher, low molecular weight components are reduced, and a high molecular weight PAS is easily obtained. Therefore, it is preferable to use such means.

The removal of the solvent is performed before moving to the following step 2. As a specific method, a method of removing stepwise during the reaction of step 1, a method of removing after step 1 and immediately before shifting to step 2, or a combination thereof can be exemplified. Also, in step 2, the solvent can be removed as long as the essence of the present invention is not impaired.
Further, it does not matter if a solvent is added during the reaction, but the amount of the organic polar solvent used in Step 2 is such that the amount of the organic polar solvent in the reaction system is 1.5 mol or more and 3.5 mol per 1 mol of the sulfidizing agent. The amount of solvent removed is adjusted so as to be less than 2.0 moles and less than 3.2 moles, and more preferably 2.2 moles and less than 3.0 moles. The removal of the solvent can be performed under any of reduced pressure, normal pressure and increased pressure.

When the solvent is distilled off, water coexisting in the reaction system or unreacted polyhalogenated aromatic compound may be distilled off. Either part or all of this is separated from the distillate and returned to the reaction system, or the distillate is quantitatively added and newly added to the reaction system to return the reaction system to a state substantially before the solvent was extracted. Is possible. In particular, PA with a very high degree of polymerization
This method is suitable for obtaining S.

Polymerization Aid In the present invention, a polymerization aid is used to obtain a PAS having a high degree of polymerization in a shorter time. Here, the polymerization aid refers to a substance having an action of increasing the viscosity of the obtained PAS.
Specific examples of such a polymerization aid include, for example, organic carboxylate, water, alkali metal chloride, organic sulfonate, alkali metal sulfate, alkaline earth metal oxide, alkali metal phosphate, alkaline earth metal And the like metal phosphates. These may be used alone or in combination of two or more. Among them, organic carboxylate and / or water are preferably used.

The alkali metal carboxylate has the general formula R
(COOM) n (wherein, R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkylaryl group or an arylalkyl group. M is lithium, sodium, potassium, rubidium and cesium. And n is an integer of 1 to 3). The alkali metal carboxylate can also be used as a hydrate or an aqueous solution. Specific examples of the alkali metal carboxylate include
Examples thereof include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. Alkali metal carboxylate, in an organic polar solvent, an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates, in approximately equal chemical equivalents It may be formed by adding and reacting. Among the above alkali metal carboxylate salts, lithium salts are highly soluble in the reaction system and have a large auxiliary effect, but are expensive, and potassium, rubidium and cesium salts are presumed to have poor solubility in the reaction system. Sodium acetate, which is inexpensive and has appropriate solubility in a polymerization system, is preferably used.

The amount of the polymerization aid used is in the range of 0.25 mol to 0.7 mol, preferably in the range of 0.3 mol to 0.6 mol, per 1 mol of the charged alkali metal sulfide.
The range of 0.35 to 0.55 mol is more preferable. If the amount is less than the above range, the effect of increasing the degree of polymerization is insufficient. If the amount exceeds the range, not only the effect of increasing the degree of polymerization is not obtained any more, but also the opposite effect is obtained depending on the polymerization time.

These polymerization aids may be contained at least in the reaction system in the subsequent polymerization step (Step 2 described later). Therefore, the timing of the addition is before the dehydration step before the start of the first-stage polymerization or during the middle of the second-stage polymerization from the start of the first-stage polymerization.
Alternatively, the timing may be any combination of these.

Polymerization Stabilizer In the present invention, a polymerization stabilizer may be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilization of the polymerization reaction system and suppresses undesirable side reactions. One measure of the side reaction is the formation of thiophenol, and the addition of a polymerization stabilizer can suppress the formation of thiophenol. Specific examples of the polymerization stabilizer include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among them, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide are preferred. Since the above-mentioned alkali metal carboxylate also acts as a polymerization stabilizer, it is included in one of the polymerization stabilizers used in the present invention. In the case where an alkali metal hydroxide is used as the sulfidizing agent, it is particularly preferable to use the alkali metal hydroxide at the same time. Can also be a polymerization stabilizer.

These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is used in an amount of usually from 0.02 to 0.2 mol, preferably from 0.04 to 0.2 mol, per mol of the charged alkali metal sulfide.
It is used in a proportion of 0.1 mol, more preferably 0.05 to 0.09 mol. If this ratio is low, the stabilizing effect is insufficient, and if it is too high, it is economically disadvantageous,
The polymer yield tends to decrease.

The timing of adding the polymerization stabilizer may be before the pretreatment step (dehydration step) before the start of the following step 1, during the start of the step 1 and in the middle of the following step 2, or at an arbitrary combination thereof. Should be fine. It is preferably before the pretreatment step or at the start of step 1. In the case where a part of the alkali metal sulfide is decomposed during the pretreatment step to generate hydrogen sulfide, the resulting alkali metal hydroxide can also be a polymerization stabilizer.

Water is present in the reaction system as an organic metal carboxylate hydrate or aqueous solution, an alkali metal sulfide hydrate or aqueous solution, or an alkali metal hydrosulfide aqueous solution, or added directly to the reaction system. Either one or both may be used.

Polymerization Reaction In the present invention, a sulfidizing agent and a polyhalogenated aromatic compound are reacted in an organic polar solvent at 200 ° C. or more and 290 ° C.
A method for producing a polyarylene sulfide by reacting within a temperature range of less than, characterized in that the above reaction is carried out by at least the following steps 1 and 2, but additional processes such as a pre-treatment step and a post-treatment step There may be a step.

Step 1: A polyhalogenated aromatic compound and a sulfidizing agent are reacted with a molar ratio of the solvent to the charged sulfidizing agent of 3.5 to 10.0 to form a polyarylene sulfide prepolymer. And a step of converting the prepolymer into a high-molecular-weight polyarylene sulfide in the presence of a polymerization aid by setting the molar ratio of the solvent to the sulphidating agent in the charge to 1.5 to less than 3.5.

Here, "converting the prepolymer to a high molecular weight polyarylene sulfide" by the step 2 means that the prepolymer is made higher in molecular weight to obtain a polyarylene sulfide having a desired degree of polymerization.

When starting the above reaction step, the reaction is preferably carried out under an inert gas atmosphere at room temperature to 220 ° C., preferably 1 ° C.
A sulfidizing agent and a dihalogenated aromatic compound are added to an organic polar solvent in a temperature range of 00 to 220 ° C. At this stage, a polymerization aid may be added. The order of charging these raw materials may be random or may be simultaneous.

The amount of water in the polymerization system in the above reaction step 1 is 0.5 to 2.0 per mole of the charged sulfidizing agent.
Preferably it is molar. Here, the amount of water in the polymerization system is an amount obtained by subtracting the amount of water removed outside the polymerization system from the amount of water charged in the polymerization system. The water to be charged may be in any form such as water, an aqueous solution, and water of crystallization. A more preferred range of the water content is 0.75 to 1.5 mol per mol of the sulfidizing agent, and 1.0 to 1.2 mol.
A range of 5 moles is more preferred. If the water content is less than the above range, it is difficult to obtain a sufficient oligomer reduction effect, while if it exceeds the above range, not only the polymerization time becomes longer,
Since the internal pressure of the polymerization vessel is greatly increased and a polymerization vessel having a higher pressure resistance is required in the polymerization vessel, it is disadvantageous in terms of economy and safety.

The sulfidizing agent is usually used in the form of a hydrate, but when the water content is less than the above range, it is preferable to add a necessary amount to supplement it. On the other hand, when the water content of the sulfidizing agent exceeds the above range, before adding the dihalogenated aromatic compound, the temperature of the mixture containing the organic polar solvent and the sulfidizing agent is raised, and excess water is removed from the system. It is preferable to remove it. When water is excessively removed by this operation, it is preferable to add and replenish the insufficient water.

As described above, as the sulfidizing agent, an alkali metal sulfide prepared in situ from an alkali metal hydrosulfide and an alkali metal hydroxide in a reaction system can also be used. Although there is no particular limitation on this method, it is desirably under an inert gas atmosphere at room temperature to 150 ° C.
° C., preferably in the temperature range from room temperature to 100 ° C., add alkali metal hydrosulfide and alkali metal hydroxide to the organic polar solvent, and at normal pressure or reduced pressure, at least 150 ° C. or more,
Preferably, a method in which the temperature is raised to 180 to 240 ° C. to distill off water is used. At this stage, a polymerization aid may be added. Further, in order to promote the removal of water, the reaction may be carried out by adding toluene or the like.

In the present invention, a polyarylene sulfide is produced by reacting a sulfidizing agent with a polyhaloaromatic compound in an organic polar solvent in the presence of a polymerization aid within a temperature range of 200 ° C. or more and less than 290 ° C. In the above method, the above-mentioned reaction is carried out by at least the following steps 1 and 2, wherein the high-molecular-weight PAS having a reduced oligomer content is used.
From the viewpoint of efficiently obtaining in a short time.

Step 1: In a temperature range of 200 ° C. or more and less than 245 ° C., the molar ratio of the solvent to the sulfided agent used is 3.5 to 10.0 or less, preferably 4.0 or more to 1
0.0 or less, a step of reacting a polyhalogenated aromatic compound with a sulfide agent to form a polyarylene sulfide prepolymer; and Step 2: the presence of a polymerization aid in a temperature range of 245 ° C or more and less than 290 ° C. A step of converting the prepolymer to a high molecular weight polyarylene sulfide by setting the molar ratio of the solvent to the sulfidizing agent to 1.5 or more and less than 3.5.

Here, additional steps such as a pre-treatment step and a post-treatment step may be provided in addition to the above two steps.

If the molar ratio of the solvent to the sulfidizing agent charged in step 1 is too small, undesirable side reactions tend to occur, and if it is too large, the time required for the reaction becomes longer. When the temperature at which Step 1 is performed is 200 ° C. or higher, a sufficiently high reaction rate is obtained, and when the temperature is lower than 245 ° C., the effect of suppressing undesired side reactions is large, and a high molecular weight PAS is easily obtained, which is preferable.

If the molar ratio of the solvent to the sulfidizing agent charged in the step 2 is less than 1.5, the formed prepolymer is deposited and rejected out of the reaction system, so that the reaction rate is extremely reduced. Any of these is not preferred because it makes it difficult to obtain a molecular weight PAS. When the temperature at which Step 2 is performed is 245 ° C. or higher, a sufficiently high reaction rate can be obtained,
If the temperature is lower than 290 ° C., decomposition of the polymer and deterioration of the solvent are difficult to occur, so that it is preferable.

Further, it is essential that the step 2 is carried out in the presence of a polymerization aid. If no polymerization aid is present, the time required for converting the prepolymer into a high-molecular-weight polyarylene sulfide becomes longer, and the process is difficult to achieve. It is not preferable because the degree of polymerization that can be performed is limited. Further, when Step 1 and Step 2 are performed outside the range of the amount of the solvent used, a sufficient auxiliary effect cannot be obtained even if Step 2 is performed in the presence of a polymerization auxiliary. In the method of the present invention in which the amount of the solvent used in step 1 and step 2 is changed and the polymerization aid is present in step 2, the amount of oligomer produced can be reduced. Instead, a PAS having a higher polymerization degree than that obtained by a method in which a polymerization aid is present in step 2 can be easily obtained.

The time point at which the step 1 is switched to the step 2 is preferably the time point at which the conversion of the polyhalogenated aromatic compound in the system reaches 85 mol% or more. If the conversion is less than 70 mol%, undesirable reactions such as decomposition are likely to occur during the subsequent polymerization in the step 2.

The conversion of the polyhalogenated aromatic compound (abbreviated herein as PHA) is a value calculated by the following equation. The residual amount of PHA can usually be determined by gas chromatography.

(A) When the polyhalogenated aromatic compound is excessively added to the alkali metal sulfide at a molar ratio Conversion: [PHA charge (mol) -PHA residue (mol)] / [PHA charge] (Mol)-PHA excess (mol)] (b) In cases other than the above (a) Conversion = [PHA charge (mol)-PHA residue (mol)] / [PHA charge (mol)] In the above, step 1 and step 2 can be performed in the same reaction vessel, but after the reaction in step 1 is completed, the obtained reaction mixture is placed in a reaction vessel different from the reaction vessel in which step 1 was performed. A reaction may be performed. That is, the reaction vessel A
In step (1), the obtained reaction mixture may be transferred to reaction vessel B, and step (2) may be continued. In this case, step 1
Since the amounts of the solvents used are different between and, the capacity of the reaction vessel in step 2 can be made smaller than that in step 1 in accordance with this. A pressure vessel such as an autoclave is usually used as the reaction vessel used in Steps 1 and 2. However, since the reaction in Step 1 is usually performed in a lower temperature range than in Step 2, the pressure vessel of the reaction vessel in Step 1 is usually used. The performance can be designed to be lower than the pressure resistance of the reactor in step 2. In view of these points, it is economically and energetically advantageous to perform Step 1 and Step 2 in separate reaction vessels.

In the present invention, the polymerization time in the above step 1 is preferably in the range of 60 to 300 minutes, and is preferably in the range of 80 to 2 minutes.
A range of 50 minutes is more preferred. If the reaction time is less than the above range, it is often difficult to sufficiently increase the degree of polymerization, and even if the time exceeds the above range, the resulting effect of increasing the degree of polymerization is reduced, which is economically disadvantageous. It becomes.

Further, the polymerization time in the above step 2 is 6
The range is preferably from 0 to 300 minutes, more preferably from 100 to 200 minutes. If the reaction time is less than the above range,
In many cases, it is difficult to sufficiently increase the degree of polymerization, and even if the time exceeds the above range, the resulting effect of increasing the degree of polymerization is reduced, which is economically disadvantageous.

By applying the method of the present invention, the polymerization degree and the economical efficiency can be maximized when the total polymerization time in which the temperature in the system including the constant temperature time, the heating time and the cooling time is 200 ° C. or more is 3 to 10 hours. PPS having excellent properties can be obtained.

Post-treatment The PAS thus obtained is usually treated with an organic solvent and / or
Or washed with water and dried.

The organic solvent used for washing is not particularly limited as long as it does not have a function of decomposing polyarylene sulfide. For example, nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone, dimethylformamide and dimethylacetamide can be used. Polar solvents, dimethyl sulfoxide, sulfoxidesulfone solvents such as dimethyl sulfone, acetone, methyl ethyl ketone, diethyl ketone, ketone solvents such as acetophenone, dimethyl ether, dipropyl ether, ether solvents such as tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, Halogen solvents such as ethylene dichloride, dichloroethane, tetrachloroethane, chlorobenzene, methanol, ethanol, propanol, butanol, pentanol, ethylene glycol Lumpur, propylene glycol, phenol, cresol, alcohol phenol based solvents such as polyethylene glycol, benzene, toluene,
Examples include aromatic hydrocarbon solvents such as xylene. Among these organic solvents, use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform or the like is preferred. In addition, these organic solvents include 1
It is used in a kind or a mixture of two or more kinds.

As a method for washing with an organic solvent, there is a method such as immersing polyarylene sulfide in an organic solvent, and it is also possible to appropriately stir or heat as necessary.

The washing temperature for washing the polyarylene sulfide with an organic solvent is not particularly limited, and is from room temperature to
Any temperature of about 300 ° C. can be selected. Although the cleaning efficiency tends to increase as the cleaning temperature increases, a sufficient effect is usually obtained at a cleaning temperature of room temperature to 150 ° C.

The ratio of the polyarylene sulfide to the organic solvent is preferably higher in the amount of the organic solvent.
A bath ratio of less than or equal to g is selected.

The PPS resin that has been washed with an organic solvent is preferably washed several times with water or warm water in order to remove the remaining organic solvent.

As a method for washing the polyarylene sulfide with water or hot water, there is a method of immersing the polyarylene sulfide in water or hot water.
If necessary, stirring or heating can be appropriately performed.

The washing temperature for washing the polyarylene sulfide with water or warm water is preferably from 20 ° C. to 220 ° C., more preferably from 50 ° C. to 200 ° C. If the temperature is lower than 20 ° C., it is difficult to remove by-products.

The water used for washing with water or hot water is preferably distilled water or deionized water. If necessary, formic acid, acetic acid, propionic acid, butyric acid, chloroacetic acid,
Dichloroacetic acid, acrylic acid, crotonic acid, benzoic acid, salicylic acid, oxalic acid, malonic acid, succinic acid, phthalic acid,
An aqueous solution containing an organic acidic compound such as fumaric acid, an alkali metal salt thereof, an alkaline earth metal salt thereof, an inorganic acidic compound such as sulfuric acid, phosphoric acid, hydrochloric acid, carbonic acid, and silicic acid, and an ammonium ion may be used.

The operation of the hot water treatment is usually carried out by adding a predetermined amount of polyarylene sulfide to a predetermined amount of water, and heating and stirring at normal pressure or in a pressure vessel.
The proportion of polyarylene sulfide to water is preferably as high as possible, but a bath ratio of 200 g or less of polyarylene sulfide to 1 liter of water is usually selected.

Produced PPS The polyarylene sulfide resin thus obtained has a high degree of polymerization in a linear form, and is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and especially oligomer content. It has excellent characteristics of reduced gel content and low content of impurities, so it has less gel and gas and excellent moldability. Not only injection molding, but also extrusion, sheet, film, fiber and pipe etc. Extruded product.

The polyarylene sulfide obtained in the present invention may be used alone or, if desired, may be used by blending the following compounding agents. Specific examples thereof include glass fiber, carbon fiber, potassium whisker, titanate whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber,
Fibrous fillers such as asbestos fibers, masonry fibers, metal fibers, silicates such as walasteinite, zeolite, sericite, mica, talc, kaolin, clay, pyrophyllite, bentonite, asbestos, alumina silicate, silicon oxide, Metal compounds such as magnesium oxide, alumina, zirconium oxide, titanium oxide and iron oxide; carbonates such as calcium carbonate, magnesium carbonate and dolomite; sulfates such as calcium sulfate and barium sulfate; calcium hydroxide; magnesium hydroxide; Non-fibrous fillers such as hydroxides such as aluminum, glass beads, ceramic beads, boron nitride, silicon carbide, graphite, carbon black and silica;
These may be hollow, and it is also possible to use two or more of these fillers in combination. In addition, these fillers are isocyanate compounds, organic silane compounds,
Pretreatment with a coupling agent such as an organic titanate-based compound, an organic borane-based compound, or an epoxy compound before use is preferable from the viewpoint of obtaining more excellent mechanical strength.

Further, the polyarylene sulfide obtained in the present invention may be used by blending with another resin as required. Although there is no particular limitation on the resin that can be blended, specific examples thereof include polyamides such as nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, and aromatic nylon, polyethylene terephthalate, polybutylene terephthalate, and polycyclohexyldiyl. Polyester resins such as methylene terephthalate and polynaphthalene terephthalate, polysulfone, polyphenylene oxide, polycarbonate, polyethersulfone, polyetherimide, cyclic olefin copolymer, polyethylene, polypropylene, polytetrafluoroethylene, carboxyl group, carboxylic ester group and acid anhydride Olefin copolymers, polyolefin elastomers, polyether ester elastomers having functional groups such as anhydride groups and epoxy groups Mer, polyetheramide elastomers, polyamide-imide, polyacetal, and a resin such as polyimide.

The polyarylene sulfide obtained in the present invention may be, if desired, a plasticizer such as a polyalkylene oxide oligomer compound, thioether compound, ester compound, or organic phosphorus compound, talc, kaolin, or organic phosphorus compound. Nucleating agents, release agents such as polyolefin compounds, silicone compounds, long-chain aliphatic ester compounds and long-chain aliphatic amide compounds, antioxidants such as hindered phenol compounds and hindered amine compounds, heat Stabilizer, calcium stearate,
Conventional additives such as lubricants such as aluminum stearate and lithium stearate, ultraviolet absorbers, ultraviolet inhibitors, coloring agents, flame retardants, and foaming agents can be added.

Addition of an alkoxysilane having at least one functional group selected from an epoxy group, an amino group, an isocyanate group, a hydroxyl group, a mercapto group and a ureide group to the polyarylene sulfide obtained in the present invention. Doing so is effective in improving mechanical strength, toughness, and the like. Specific examples of such compounds include epoxy-group-containing alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Compounds, γ-mercaptopropyltrimethoxysilane, mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-
Ureido group-containing alkoxysilane compounds such as (2-ureidoethyl) aminopropyltrimethoxysilane;
-Isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropyl Isocyanato group-containing alkoxysilane compounds such as ethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ Amino-containing alkoxysilane compounds such as -aminopropyltrimethoxysilane, and hydroxyl-containing alcohols such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane Xysilane compounds and the like can be mentioned.

The preferable addition amount of the silane compound is 0.1 to 100 parts by weight of the polyphenylene sulfide resin.
A range of from 0.5 to 5 parts by weight is selected.

[0078] Further, as the application, for example, a sensor,
LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable condenser cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors , Magnetic head base, power module, semiconductor, liquid crystal, F
Electric and electronic parts such as DD carriage, FDD chassis, motor brush holder, parabolic antenna, computer related parts; VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio parts Audio equipment parts such as laser disk (registered trademark) and compact disk,
Lighting parts, refrigerator parts, air-conditioner parts, typewriter parts, word processor parts, etc., household and office electrical product parts; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs , Motor parts, mechanical parts such as lighters and typewriters: microscopes, binoculars,
Optical equipment such as cameras and clocks, and precision machinery-related parts; water faucet tops, mixing faucets, pump parts, pipe joints, water flow control valves, relief valves, hot water temperature sensors, water flow sensors, water meter housings, etc. Surrounding parts: valve alternator terminal, alternator connector, IC regulator, potentiometer base for light deer, various valves such as exhaust gas valve, various pipes related to fuel, exhaust system, intake system, air intake nozzle snorkel, intake manifold, fuel pump , Engine cooling water joint, carburetor main body, carburetor spacer, exhaust gas sensor,
Cooling water sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane , Wiper motor related parts, Distributor, Starter switch, Starter relay, Transmission wire harness, Window washer nozzle,
Air conditioner panel switch board, fuel related electromagnetic valve coil, fuse connector, horn terminal, electrical component insulation board, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition device case , Vehicle speed sensor, cable liner, and other automobile and vehicle related parts, and other various applications.

[0079]

EXAMPLES Hereinafter, the method of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, the measuring method of physical properties is as follows.

(1) Polymer yield The yield of polyarylene sulfide is calculated by the weight (theoretical amount) assuming that all the sulfidizing agent containing 1 equivalent of sulfur in the reactor after the dehydration step was converted to polyarylene sulfide.
And the ratio of the yield of polyarylene sulfide to the total. If the sulfidizing agent is charged in excess of the polyhalogenated aromatic compound, it may not be possible to convert all to PAS, but even in such a case, consider the amount of the sulfidizing agent as a reference. And

(2) Melt viscosity of polymer Capillograph C1 manufactured by Toyo Seiki Co., Ltd. (die length 10 mm,
Using a die hole diameter of 1 mm), the measurement was performed at 300 ° C., and the melt viscosities at a shear rate of 200 / s were compared.

(3) Impurity content of polyarylene sulfide The impurity content of polyarylene sulfide was determined by soxhlet extraction of 10 g of polymer with 100 g of chloroform for 3 hours, and the weight of the component obtained when chloroform was distilled off from this extract. Of the polymer weight.

Example 1 Pre-step Into a 1 liter autoclave equipped with a stirrer, 118 g (1.00 mol) of 47% sodium hydrosulfide, 42.9 g (1.03 mol) of 96% sodium hydroxide, N-methyl −
163 g (1.65 mol) of 2-pyrrolidone (NMP),
36.8 g (0.45 mol) of sodium acetate and 150 g of ion-exchanged water are charged, and 2
After gradually heating to 25 ° C. over about 3 hours to distill 210 g of water and 2 g of NMP, the reaction vessel was cooled to 160 ° C. The amount of residual water in the system per mole of the charged alkali metal sulfide was 1.15 mole. The amount of hydrogen sulfide scattered was 0.02 mol.

Step 1 Next, 147 g of p-dichlorobenzene (p-DCB)
(1.00 mol) and 421 g (4.25 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. At this stage, the molar ratio of the solvent to 1 mol of the sulfidizing agent was 6.0. Then, while stirring at 400 rpm, 200 ° C.
To 235 ° C. at a rate of 0.6 ° C./min.
C. for 50 minutes. Next, the extraction valve at the top of the autoclave was gradually opened, and 310 g of the solvent was distilled off over 40 minutes while maintaining the internal temperature at 235 ° C. At this time, N
23 g water, p-
A solution of 5.9 g of DCB dissolved in 20 g of NMP was added.

Step 2 At this stage, the molar ratio of the solvent to 1 mol of the sulfidizing agent was 3.0.

Thereafter, the temperature was raised to 270 ° C. at a rate of 0.8 ° C./min and held for 85 minutes. After that, 1.
It was cooled at a rate of 0 ° C./min and then rapidly cooled to around room temperature.

After treatment The contents were taken out, 1.0 liter of warm water and 5 g of acetic acid were added, and the mixture was stirred. The solid matter was filtered off through a sieve (200 mesh), and the obtained particles were washed several times with 1 liter of warm water. ,
After filtration, PPS polymer particles were obtained. This was dried with hot air at 80 ° C. for 3 hours.

The melt viscosity of the obtained PAS was 400 Pa ·
s, the yield was 93%, and the impurity content was 0.8 wt%.

The same operation as described above was performed halfway, and the polymerization system was quenched immediately before the solvent removal operation. When p-DCB in the polymerization content was quantified by gas chromatography, the conversion was 97%.

[Comparative example 1]
In the entire polymerization process, polymerization and recovery operations were performed in the same manner as in Example 1, except that the molar ratio of the solvent to 1 mol of the sulfidizing agent was changed to 6.0. The melt viscosity of the obtained PAS was 270 Pa · s, the yield was 91%, and the impurity content was 1.1 wt%.

When the solvent was not removed on the way, a sufficiently high degree of polymerization PAS was not obtained.

Comparative Example 2 A polymerization and recovery operation was carried out in the same manner as in Example 1 except that sodium acetate was not added.
The melt viscosity of the obtained PAS is 20 Pa · s, and the yield is 74.
% And the impurity content were 1.0 wt%.

It can be seen that when no polymerization aid is used, only a very low viscosity PAS can be obtained.

[Comparative Example 3] In step 1, 147 g of p-DCB
(1.00 mol) and 130 g of NMP (1.
Polymerization and recovery were carried out in the same manner as in Example 1 except that the molar ratio of the solvent to 1 mol of the sulfidizing agent was 1.31. The melt viscosity of the obtained PAS is 330P.
a.s, the yield was 93%, and the impurity content was 6.4 wt%.

If the amount of the solvent used in step 1 is not appropriate,
It can be seen that only PAS having a high impurity content can be obtained.

[0096]

As described above, according to the present invention,
A high molecular weight PAS having a reduced oligomer content can be efficiently obtained in a short time.

Claims (6)

[Claims] 1. A method for producing a polyarylene sulfide by reacting a sulfidizing agent with a polyhalogenated aromatic compound in an organic polar solvent within a temperature range of 200 ° C. or more and less than 290 ° C. A method for producing polyarylene sulfide, which is performed at least in steps 1 and 2. Step 1: a step of reacting the polyhalogenated aromatic compound with the sulfidizing agent to form a polyarylene sulfide prepolymer by setting the molar ratio of the solvent to the charged sulfidizing agent to 3.5 or more and 10.0 or less, And Step 2: a step of converting the prepolymer into a high-molecular-weight polyarylene sulfide in the presence of a polymerization aid by setting the molar ratio of the solvent to the charged sulfidizing agent to 1.5 or more and less than 3.5. 2. The method according to claim 1, wherein the step (1) is performed within a temperature range of 200 to 245 ° C., and the step (2) is performed at a temperature of 245 to 290 ° C.
The method for producing a polyarylene sulfide according to claim 1, wherein the method is performed in a temperature range of less than. 3. After reacting the polyhalogenated aromatic compound in step 1 so that the conversion is 85% or more,
The method for producing polyarylene sulfide according to claim 1, wherein the process proceeds to step 2. 4. The method according to claim 1, wherein the total polymerization time in which the temperature in the system including the constant temperature time, the temperature raising time and the temperature lowering time is 200 ° C. or more is 3 to 10 hours.
The method for producing a polyarylene sulfide according to the above item. 5. The method according to claim 1, wherein at least the step 2 comprises an organic carboxylate, water, an alkali metal chloride, an organic sulfonate, an alkali metal sulfate, an alkaline earth metal oxide, an alkali metal phosphate, an alkaline earth metal phosphorus. The method for producing a polyarylene sulfide resin according to any one of claims 1 to 4, wherein the method is carried out in the presence of at least one polymerization aid selected from acid salts. 6. The reaction of step 1 wherein the reaction mixture obtained after the reaction in step 1 is transferred to a reaction vessel different from the reaction vessel in which step 1 was carried out, and the reaction in step 2 is carried out. The method for producing a polyarylene sulfide resin according to any one of the above.