JP2543673B2 - A method for producing poly (arylene sulfide) with excellent handling properties - Google Patents

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 abbreviated as PAS), and more specifically, it has excellent handleability without using a polymerization aid such as an organic acid salt. The present invention relates to a novel production method for inexpensively producing high molecular weight or ultra high molecular weight PAS having a particle property. In the present invention, high molecular weight PAS
And ultra high molecular weight PAS are about 1000 each.
~ 7,000 poise and about 7,000 poise or more (310
The value of PAS at a temperature of ℃ and shear rate of 200 (sec ^-1 ) is shown.

In recent years, a thermoplastic resin having higher heat resistance has been required as a thermoplastic resin used for electronic equipment parts, automobile parts and the like.

PAS also has a property as a resin that can meet the demand, but PAS represented by this polyphenylene sulfide has a particularly high strength because it is difficult to obtain a PAS having a sufficiently high molecular weight. There has been a problem that it is extremely difficult to obtain the required fibers and films and the molded products required to have high impact strength.

The present invention provides a method for inexpensively producing PAS having a remarkably high molecular weight in order to solve these problems.

[0005]

2. Description of the Related Art A typical manufacturing method of PAS is N
A method of reacting a dihaloaromatic compound with sodium sulfide in an organic amide solvent such as -methylpyrrolidone is disclosed in Japanese Patent Publication No. 45-3368. However, the PAS produced by this method has a low molecular weight and a low melt viscosity, so that it has been difficult to process it into a film, sheet, fiber or the like.

From such a point, PAS having a high degree of polymerization is obtained.
In order to obtain the above, various methods improved from the above methods have been proposed. In the most representative Japanese Patent Publication No. 52-12240, an alkali metal organic acid salt is used as a polymerization aid in the reaction of a dihaloaromatic compound with sodium sulfide in an organic amide solvent such as N-methylpyrrolidone. ing. According to this method, the addition amount of the polymerization aid is required to be approximately equimolar to the alkali metal sulfide, and in order to obtain PAS having a higher polymerization degree, it is expensive among various polymerization aids. It is necessary to use large amounts of lithium acetate and sodium benzoate, and as a result PA
It is considered that the manufacturing cost of S will increase and it will be industrially disadvantageous. Further, in this method, a large amount of organic acid or the like may be mixed in the treated wastewater at the time of PAS recovery after the polymerization reaction, which may cause pollution problems.
It seems that there are major problems from an economical point of view, such as requiring a large amount of equipment and running costs for reuse.

As another method for obtaining PAS having a high degree of polymerization, there has been proposed a method using a polyhaloaromatic compound of trihalo or higher as a cross-linking agent or a branching agent during the polymerization or at the final stage of the polymerization (Japanese Patent Laid-Open Publication No. Sho. No. 53-136100, etc.).

A high molecular weight PAS having an apparent melt viscosity of tens of thousands of poise can be easily obtained by the method of increasing the degree of polymerization only with a crosslinking agent. However, since it is a highly cross-linked or branched polymer, it has poor spinnability, making it difficult to process films and fibers, and even if a molded product is obtained, the molecular chain is basically There was a problem that it was only mechanically extremely fragile because it was short. Possible Solution In view of the above points, the present inventors have proposed a method for inexpensively producing a linear PAS having a high melt viscosity and without using a polymerization aid such as an alkali metal organic acid salt. As a result of a detailed study of the polymerization mechanism in a simple polymerization system of an alkali metal sulfide and a dihaloaromatic compound to find out, the amount of coexisting water and the polymerization temperature were particularly remarkable in the pre-polymerization stage and the post-polymerization stage under various polymerization conditions. It was found that high-molecular-weight PAS can be produced without using an auxiliary agent (see JP-A-61-7332).

Next, the inventors of the present invention found a method for producing a high to ultra high molecular weight PAS by once separating the prepolymer, then again dispersing it in a water-containing polar solvent and heating it (special feature: No. 59-188533).

[0010]

The above-mentioned methods developed by the present inventors all use liquid-liquid two-phase separation (dispersed phase: concentrated polymer solution phase,
Continuous phase: high molecular weight PAS caused by dilute polymer solution phase)
It is a method to generate the so-called "phase separation polymerization".

In this phase separation polymerization method, it is possible in the laboratory to prepare an ultra-high molecular weight PAS or a PAS with a high-concentration charged formulation. However, when industrially producing PAS in a commercial plant, the dispersed phase rushes into a so-called “sticky state” during polymerization, and the produced polymers coalesce and coalesce to cause enlargement and coarsening,
Furthermore, there is a risk that it will become difficult to stir and withdraw from the polymerization tank by agglomerating, and in order to industrially produce ultra-high molecular weight PAS or high-molecular weight PAS with a high-concentration charged formulation, it is necessary to use engineering techniques. The above problem remained.

Both the method described in Japanese Patent Application Laid-Open No. 61-7332 and the method disclosed in Japanese Patent Application No. 59-188533 are highly effective without using a crosslinking agent or a polymerization aid (organic acid salt, etc.). This is a so-called "phase separation polymerization" method for inexpensively producing a linear PAS having a molecular weight or an ultrahigh molecular weight. Both of them have a melt viscosity of 5 to 3000 poise (310 ° C, shear rate = 200 (sec) ^-1 ). (Measurement), and prepare a prepolymer in a strong alkaline water-containing aprotic organic polar medium containing the prepolymer and a sufficient amount of water at about 240 ° C.
The mixture is heated to 290 ° C. and, under the state of liquid-liquid two-phase separation (dispersed phase: concentrated polymer solution phase, continuous phase: diluted polymer solution phase), polymerization is allowed to proceed to obtain a high molecular weight polyarylene sulfide.

At the beginning of the two-phase separation polymerization, the viscosity of the dispersed phase is relatively low. Therefore, even if the produced polymers collide with each other by stirring and coalesce, they are redispersed by stirring to cause enlargement. Not proceed. However, as the polymerization progresses, the viscosity of the dispersed phase becomes high, and the dispersion phase enters a so-called "sticky state" range where redispersion is difficult (this range is particularly wide in a high-concentration charged formulation).

As a result, the produced polymers coalesce and coalesce and enlarge without being redispersed, leading to coarse particles and finally to agglomeration.

[0015]

Means for Solving the Problems] Abstract The present invention, viscous dispersion phase, the "sticky stat
Before entering the range of `` e '', by controlling the temperature to prevent the dispersed phase from bloating, at the same time by continuing the polymerization reaction in that state, the ultra-high molecular weight of the particle properties with excellent handling properties. It is intended to manufacture PAS and high molecular weight PAS (high-concentration prescription).

That is, the method for producing a polyarylene sulfide having excellent handling property according to the present invention is a method for obtaining a polyarylene sulfide by reacting an alkali metal sulfide with a dihaloaromatic compound in an aprotic polar organic solvent. , A pre-polymerization step for producing a pre-polymer having a melt viscosity lower than a desired melt viscosity and a post-polymerization step for further pre-polymerizing the pre-polymer to obtain a pre-polymerization step. By precipitating the resulting prepolymer from the reaction system until it has a melt viscosity of 5 to 300 poise and then adding it to an aprotic polar organic solvent containing 5.5 to 15 mol of water per kg of the organic solvent. , The prepolymer having an arylene group of 0.5 to 3.5 mol / kg of the organic solvent. There redispersed to coexist,
In the strong alkaline state (that is, the pH value of the reaction solution diluted 10 times with water is 9.5 or more), the following post-polymerization step is performed. Second-stage polymerization step: (a) The reaction system is maintained at a temperature (T ₁ ) in the range of 257 to 290 ° C. for at least 10 minutes with stirring. (B) Next, the temperature of the reaction system is lowered to bring the reaction system to a temperature (T ₂ ) in the range of 220 to 250 ° C. at least 2.
Hold for 0 hours with stirring. (C) Then, if necessary, the reaction system is heated to 250 to 29.
Hold at a temperature (T ₃ ) in the range of 0 ° C. with stirring for a time sufficient to produce a polyarylene sulfide of the desired melt viscosity. Effect According to the present invention, an ultra high molecular weight P having excellent handling property
It has become possible to industrially manufacture AS or high molecular weight PAS (high-concentration prescription) in a commercial plant. In the present invention, "PAS having excellent handling property" means that in the slurry state, the slurry taken out from the polymerization tank can be easily transported, solid-liquid separation, and the like, and in the dry state, it has a free-flow property. Means a particulate PAS having excellent characteristics. This good handling property is based on the particle properties of the PAS particles obtained by the present invention. That is, the PAS particles according to the present invention, in its preferred embodiment, have a particle size of about 0.25 to about 0.25.
Sharp particle size distribution of about 5.0 mm and 0.25 to 0.
This is because it has a bulk density of 8 (g / ml), and this good handling property is naturally exhibited from this particle property.

According to the present invention, a high-concentration high-molecular-weight PAS can be prepared, and the productivity can be greatly improved.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Raw material and apparatus for producing PAS In the method for producing granular PAS having excellent handleability according to the present invention, the reaction between an alkali metal sulfide and a dihaloaromatic compound is carried out under specific conditions. It consists of Alkali Metal Sulfides The alkali metal sulfides used in the present invention include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and mixtures thereof.
These alkali metal sulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Of these alkali metal sulfides, sodium sulfide is the cheapest and industrially preferable.

Alkali metal disulfides and alkali metal thiosulfates, which may be present in trace amounts in the alkali metal sulfides, are used in combination with a small amount of alkali metal hydroxide to remove these impurities or convert them to sulfides. You can measure the conversion. Dihalo Aromatic Compound The dihalo aromatic compound used in the present invention may be, for example, a dihalo aromatic compound described in JP-A-59-22926. In particular, p-dichlorobenzene, m-dichlorobenzene, 2,5-dichlorotoluene, p-dibromobenzene, 1,4-dichloronaphthalene, 1-methoxy-2,5-dichlorobenzene,
4,4'-dichlorobiphenyl, 3,5-dichlorobenzoic acid, p, p'-dichlorodiphenyl ether, 4,
4'-dichlorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfoxide, 4,4'-dichlorodiphenyl ketone and the like are preferable. Among them, those containing paradihalobenzene represented by p-dichlorobenzene as a main component are preferable.

Copolymers containing two or more different reaction units can be obtained by appropriate selective combination of dihaloaromatic compounds. For example, when p-dichlorobenzene and m-dichlorobenzene or p, p'-dichlorodiphenyl ether are used in combination,

[0022]

Embedded image With repeating units

[0023]

Embedded image Or

[0024]

Embedded image A copolymer containing a repeating unit can be obtained.

Although the PAS according to the present invention is a polymer of the above dihaloaromatic compound, it is a monohalo compound (not necessarily an aromatic compound) for forming a terminal of the produced polymer or controlling the polymerization reaction or the molecular weight. Good)
It is also possible to use together, or to use a polyhalo compound of trihalo or more (not necessarily an aromatic compound) in order to form a branched or crosslinked polymer. Specific examples where these monohalo or polyhalo compounds are aromatic compounds will be apparent to those skilled in the art as the monohalo or polyhalo derivatives of the above specific examples.
Specifically, for example, by using dichlorobenzene in combination with a small amount of trichlorobenzene, a branched phenylene sulfide polymer can be obtained. However, in order to obtain fibers, films and the like, the PAS is preferably substantially linear, and the degree of branching is preferably small. Polymerization solvent As the aprotic organic polar solvent used in the polymerization reaction of the present invention, N-methylpyrrolidone (hereinafter referred to as NMP
, N-ethylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylcaprolactam, tetramethylurea, dimethylimidazolidinone, hexamethylphosphoric triamide, and other organic amides (carbamic acid amide) And organic ureas and mixtures thereof. Of these, N-methylpyrrolidone is particularly preferable.

The amount of the organic polar solvent used in the reaction system is 0.2 to 5 k per 1 mol of the arylene group in the coexisting prepolymer.
g, particularly preferably 0.3 to 2 kg is preferred. Reaction apparatus Among the various steps in the polymerization method of the present invention, in particular, the dehydration step for controlling the water content, which is usually performed before the initiation of the polymerization reaction for producing the prepolymer, has a Ti content of at least a portion in contact with the reaction solution. It is extremely desirable to use a reaction apparatus composed of a material from the viewpoints of preventing the decomposition reaction of the solvent and the polymer, and preventing the contamination of the product with heavy metal salts.

In the present invention, since stirring is indispensable for chemical granulation of granular PAS, it is necessary that the reactor be equipped with a stirring device. Manufacturing of PAS The method of manufacturing PAS is described in JP-A-61-73 as described above.
No. 32, and the phase separation polymerization method described in Japanese Patent Application No. 59-188533. In the former, a prepolymer is first produced, and a large amount of water is added to the reaction solution without separating the prepolymer from the reaction solution.
This is a method of causing phase separation at a high temperature and further continuing the polymerization (hereinafter abbreviated as method A). On the other hand, in the latter, a prepolymer is first produced, and the prepolymer is once separated from the reaction solution, and then redispersed in a fresh water-containing organic polar solvent to cause phase separation at high temperature to form a polymer. This is a method of updating (hereinafter abbreviated as method B).

The production method of the present invention is a method which is carried out at least via a later-described polymerization step, which can be said to belong to the category of Method B in the present invention. First-stage polymerization step In the present invention, the pre-polymer from the first-stage polymerization is once separated from the reaction solution, and then the second-stage polymerization step is carried out.
It can be any purposeful one that is poise. It can be said that the former step in the present invention belongs to the category of Method B in that the prepolymer is separated from the reaction solution and subjected to the next step. However, the polymerization conditions themselves in the former polymerization step are not necessarily those of Japanese Patent Application No. -188533
It is not limited to those described in the specification.

One specific example of the reaction conditions in the first-stage polymerization step in the present invention is the polymerization conditions adopted in the first-step polymerization step of the invention described in the specification of the present application, which is described in Japanese Patent Application Laid-Open No. 61-190224 (specifically, per kg of organic solvent). The amount of the arylene group and water and the conversion rate of the charged dihaloaromatic compound, etc.).

That is, specifically, the amount of the organic solvent used in the reaction system is 0.2 per 1 mol of the charged amount of alkali metal sulfide (approximately the same as 1 mol of charged dihaloaromatic compound).
~ 5 kg and 0.5-5.0 water per kg of the organic solvent
In the presence of mol, preferably at a temperature of 180 to 240 ° C., the conversion of the charged dihaloaromatic compound between the alkali metal sulfide and the dihaloaromatic is 50 to 98 mol%.
Then, the reaction is carried out until the melt viscosity of the produced prepolymer becomes 5 to 300 poise.

In this case, a dehydration operation is usually carried out prior to the polymerization for forming the prepolymer so as to adjust the amount of water in the reaction system. At this time, a part of the alkali metal sulfide is decomposed to form a strongly alkaline substance, so that the reaction system becomes sufficiently strongly alkaline without adjustment (details described later).

When carrying out the polymerization of the present invention, a small amount of alkali such as alkali metal hydroxide or alkaline earth metal hydroxide can be added to the polymerization system. This may increase the stability of the system. In addition, if necessary, various salts, for example, carboxylic acid alkali metal salts, carboxylic acid alkaline earth metal salts, sulfonic acid alkali metal salts, lithium chloride, lithium carbonate, potassium fluoride, etc. of the polymerization method of the present invention. It can be added within a range that does not significantly impair the characteristics.

In the present invention, the conversion rate of the dihaloaromatic compound is calculated by the following formula. (A) When a dihaloaromatic compound (abbreviated as DHA) is added in an excessive molar ratio to the alkali metal sulfide (B) In cases other than (a) The prepolymer obtained by carrying out the first-stage polymerization step is
The post-polymerization step can be carried out in a wet state as it is separated from the reaction solution or in a dry state. Separated from the reaction solution of the second-stage polymerization step stage polymerization step, the prepolymer obtained in the first-stage polymerization step, in the latter stage polymerization step, an organic solvent 1kg of water per 5.5 to 15.0 moles, more preferably 6.0 In an aprotic polar organic solvent containing 0.5 to 12.0 mol of arylene groups per 1 kg of the organic solvent.
Re-disperse so that ~ 3.5 mol coexist, and in a strongly alkaline state (that is, the pH value of the reaction solution diluted 10 times with water is 9.5 or more), while stirring, first, the reaction system is cooled to 25
The temperature (T ₁ ) in the range of 7 to 290 ° C., more preferably 260 to 280 ° C., is 10 minutes or more, more preferably 20.
Hold for not less than 1 minute and not more than 20 hours. T ₁ does not necessarily have to be constant within the above range.

Next, the temperature of the reaction system is rapidly lowered before the reaction reaches the "sticky state" of the dispersed phase, and the reaction is carried out to 2
20 to 250 ° C. range, more preferably 230 to 245
The temperature (T ₂ ) in the range of ° C is maintained for 2.0 hours or more, more preferably 3.0 hours or more and 50 hours or less. T ₂
However, it does not have to be constant within the above range.

In the latter-stage polymerization step of the present invention, it is essential to carry out the temperature conditions of T ₁ and T ₂ . Therefore, after the condition of T ₂ is realized, the reaction may be continued at the temperature of T ₂ until the PAS having the desired melt viscosity is obtained, and the subsequent polymerization time may be shortened. If desired, the reaction system is
Range to 290 ° C., and more preferably may be continued in the range of 260 to 280 ° C., the polymerization was re-increasing the temperature of the temperature (T _3).

The first temperature (T
₁ ) is in the range of 257 to 290 ° C., more preferably 26
It is quite high in the range of 0 to 280 ° C. This is to more reliably dissolve the prepolymer and more reliably achieve the liquid-liquid two-phase separation state. If the temperature is 257 ° C or lower, the dissolution of the prepolymer may be insufficient, while if it is 290 ° C or higher, the solvent or polymer may be decomposed. Further, if the reaction system is kept at the temperature T ₁ for less than 10 minutes, dissolution of the prepolymer will be insufficient and liquid-liquid two-phase separation may be insufficient.

Then, the temperature of the reaction system is suddenly lowered to immediately reach the range of 220 to 250 ° C., more preferably 230 to 24.
The temperature (T ₂ ) in the range of 5 ° C. is maintained by lowering the temperature of the disperse phase and avoiding the “sticky state” of the disperse phase, thereby allowing the disperse phase to coalesce and coalesce when they collide. This is to prevent this. At 250 ° C or higher, coalescence of dispersed phases
The prevention of coalescence is insufficient, while at 220 ° C. or lower, the polymerization reaction rate in the dispersed phase remarkably decreases, which is not preferable.

The temperature of the reaction system drops sharply (T ₁ →
At the time of T ₂ ), the temperature of the reaction system is once lowered to a predetermined temperature T ₂ or lower, particularly 230 ° C. or lower, and then the predetermined T
_{When the} temperature is increased to _2, it is possible to more reliably prevent coalescence / coalescence of the dispersed phases in the subsequent polymerization reaction step. Even if the temperature of the disperse phase becomes T ₂ , it is in a supercooled state for a while, and there is a possibility that coalescence and coalescence will occur.
This is because it is presumed that if the temperature is lowered to T ₂ or lower, it is possible to more reliably escape from the supercooled state.

Temperature difference between T ₁ and T ₂ ΔT (= T ₁ −
T ₂ ) is preferably 8 ° C. or higher, more preferably 9 to 70.
Since it is possible to more reliably prevent the coalescence / coalescence of the dispersed phases in the subsequent polymerization reaction step, since the temperature is ℃,
preferable. As described above, the polymerization reaction may be continued at this temperature T ₂ until it grows into a polymer having a desired melt viscosity. However, when it is desired to shorten the polymerization time, the reaction or the like is maintained at a temperature (T ₃ ) in the range of 250 to 290 ° C., more preferably 260 to 280 ° C., and PAS having a desired melt viscosity is obtained. The reaction may be continued until is generated. At this time, it is preferable that the temperature is again raised to the temperature T ₃ after the reaction at the temperature T ₂ is continued for at least 2.0 hours or more, more preferably 3.0 hours or more and 50 hours or less. If the reaction at the temperature T ₂ is less than 2.0 hours, the polymerization reaction in the dispersed phase does not proceed until the dispersed phase particles become sufficiently solid, so that when the temperature is reheated, coalescence of the dispersed phase
There is a risk of coalescence. If the temperature T ₃ exceeds 290 ° C., the solvent or polymer may be decomposed, which is not preferable.

The second-stage polymerization step is carried out under strongly alkaline conditions, that is, the pH value of the reaction solution diluted 10 times with water is 9.5 or more.

This alkaline condition is used in the present invention, except when it is realized by carrying out the first-stage polymerization step, and in the present invention, a suitable alkaline agent, particularly one which is soluble in the reaction solution, such as an alkali metal or alkaline earth metal alkoxide is used. It is usually not achieved without the addition of (including phenoxide), oxides, hydroxides, carbonates, borates, etc. Post-treatment The PAS obtained by the method of the present invention has an excellent handling property and therefore has a great feature that the post-treatment can be extremely easily performed.

That is, after the completion of the polymerization reaction, the reaction slurry can be easily unloaded from the reaction vessel, so that there is substantially no trouble that the polymer remains in the reaction vessel. The reaction slurry that is unloaded next can be screened with only the polymer particles by using a normal screen (opening of about 0.1 mm). The screened polymer can be recovered as powder PAS having excellent free-flow properties by washing with water, washing with a solvent (washing with acetone, etc.), and if necessary, pickling and drying. Properties and Uses of Produced PAS PAS produced by the method of the present invention generally has an average particle size in the range of 0.25 to 3 mm and a bulk density of 0.25 (g / m).
It is a polymer having the above-mentioned particle size 1) and excellent in free flow property. However, if the bulk density is too high, the particles are too dense and cleaning is difficult. Therefore, the bulk density is preferably 0.8 (g / ml) or less. Since the PAS produced by the method of the present invention has excellent free-flow properties, it can be easily transported, packed into bags, stored, etc., and when melt-processed, the hopper drops well, and it can be transferred to a melt-processing machine. It has excellent biteability.

Furthermore, since the PAS produced by the method of the present invention is a polymer having a high molecular weight or an ultrahigh molecular weight, a film or fiber having a very high elongation can be obtained from the PAS of the present invention. . Further, a molded product having very high impact strength and bending strength can be obtained at low cost.

The PAS obtained by the method of the present invention is
In addition, polyphenylene sulfide copolymer, poly m-phenylene sulfide, poly p-phenylene sulfide with different degree of polymerization, polyether ether ketone, polyether sulfone, polysulfone, polyimide, polyamide,
Polyphenylene ether, polyarylene, polycarbonate, polyacetal, crystalline or non-crystalline polyester, fluororesin, polystyrene, polyolefin,
It can also be used as a composition mixed with a synthetic resin such as ABS or one or more elastomers such as olefin rubber, fluorine rubber, silicone rubber, hydrogenated SBR, butyl rubber, polyester rubber and polyamide rubber.

Furthermore, the PA obtained by the method of the present invention
Carbon fiber, glass fiber, calcium silicate fiber, potassium titanate fiber, silica fiber, calcium sulfate fiber, fibrous filler such as asbestos or mica, silica powder, alumina powder, titanium oxide powder, calcium carbonate powder, talc It can also be used as a composition in which it is mixed with one or more powdery fillers such as clay, glass powder, calcium silicate powder, and calcium sulfate powder.

[0046]

EXAMPLES Example 1 NMP1 was added to a Ti-lined 20 liter autoclave.
1.0 kg and hydrous sodium sulfide (solid content 45.98%) 2
5.0 mol was charged, and 82.5 mol of water and 2.1 kg of NMP were distilled while heating up to about 203 ° C. and heating. Paradichlorobenzene (hereinafter abbreviated as p-DCB)
24.9 mol and 3.1 kg of NMP were added {(arylene group / NMP) = 2.5 (mol / kg), (total water amount / NMP) = 3.7 (mol / kg)}.

Polymerization was carried out at 220 ° C. for 5 hours to obtain a polymerized slurry. Melt viscosity η of polymer in this slurry
^* Was 125 poise. Water was added to this polymerization slurry (total water content / NMP) = 10.0 (mol / kg) to carry out polymerization at 260 ° C. for 1 hour to obtain a reaction slurry (S-1). The melt viscosity η ^* of the polymer in (S-1) was 220 poise.

About half of the slurry (S-1) was filtered,
The liquid phase is separated, the solid content is recovered and the pH is 13.1 NaO.
It was washed with an H 2 aqueous solution to obtain a coarse granular prepolymer. Grind this with a mixer to make fine particles of about 2 mm or less, wash again with NaOH aqueous solution of pH 13.1, then NMP
The wet cake of the cleaned prepolymer having reduced harmful substances was obtained by removing the adhering water by washing twice with.

108 g of prepolymer (1.0 basic mole)
The solvent-containing wet cake containing the above was transferred to a 1 liter Ti-lined autoclave, NMP and NaOH 2 g were added, and water was further added (total water amount / NMP) = 10.0.
(Mol / kg), (total arylene group / NMP) = 2.0
(Mol / kg). Then heat with stirring, T ₁ = 260 ° C. for 1.0 hour, and T ₂ = 248 ° C.
The reaction was carried out at (ΔT = 12 ° C.) for 5 hours. After cooling, the autoclave was opened and the slurry was taken out (10-fold diluted aqueous solution pH = 11.3), the polymer was sieved using a screen with a 0.1 mm opening, and washing with acetone / washing with water was repeated 3 times and drying. , A polymer was obtained. The polymer obtained is
It was an ultra high molecular weight PAS having an average particle diameter of 1.2 mm, a bulk density of 0.34 (g / ml), and a melt viscosity of 16400 poise (η _inh = 0.66), and the handling property was generally good.

The melt viscosity η ^{* of the} examples of the present invention is
The sampled reaction solution slurry is suction filtered, solids are washed with water / acetone, filtered and dried under reduced pressure at 100 ° C to obtain a powdery sample at 320 ° C using a hot press.
For 30 seconds, press the sheet for 30 seconds to form a sheet of about 0.2 mm, and use a Koka flow tester to measure the temperature at 310 ° C and obtain the value at a shear rate of 200 (sec) ^-1. It is a thing. The solution viscosity η _inh was determined by dissolving the powdery sample obtained in the same manner in 1-chlornaphthalene at a concentration of 0.4 g / dl, and measuring 206 ° C.
It was obtained by measuring at the temperature of. Example 2 A Ti-lined 200 liter autoclave equipped with a stirrer with paddle type stirring blades (bottom part: equipped with a push-up valve for clearance (clearance 10 mm)), NMP 119 kg, and water-containing Na ₂ S (solid content 45.98%) 250 In a N ₂ stream, the temperature was raised to about 203 ° C. with stirring at 140 RPM and 880 mol of water and NMP 1 were added.
9.5 kg was distilled.

Then, 247 mol of p-DCB and 3 mol of metadichlorobenzene were added to {(arylene group / NM
P) = 2.5 (mol / kg), (total water amount / NMP) =
4.0 (mol / kg)}, polymerization was carried out at 220 ° C. for 5 hours to produce a prepolymer (solution viscosity = 50 poise, DCB conversion 93 mol%).

Water 606 was added to the reaction solution containing the prepolymer.
Additional moles were added {(total water amount / NMP) = 10.0 (mol / kg), (total arylene group / NMP) = 2.5 (mol / kg). Then, while stirring at a rotation speed of 140 RPM, the temperature was once raised to 265 ° C., held for 30 minutes, and immediately cooled.

Next, the bottom push-up valve was opened, and the whole reaction slurry was unloaded into the unloading tank. Virtually no polymer remained in the autoclave. Withdraw the reaction slurry from the unloading tank and use a screen with an opening of 0.1 mm.
It separated into a prepolymer (granular) and another part (salt-containing solvent).

After washing the prepolymer with an aqueous NaOH solution having a pH of 13.1, the prepolymer was washed twice with NMP to remove the attached water and obtain a wet cake of the washed prepolymer in which harmful substances were reduced. When a part of the wet cake was sampled and the dry weight thereof was calculated to calculate the prepolymer yield, it was about 78% with respect to the charged para and metadichlorobenzene. This prepolymer has an average particle size of 0.4
mm, the bulk density was 0.31 (g / ml), and the handleability was not very good. The melt viscosity η ^* was 190 poise.

The prepolymer was charged into the above 200 liter autoclave together with 390 g of NaOH, and N was added.
MP and water added, (total water / NMP) = 10.
0 (mol / kg), (total arylene group / NMP) = 2.
It was readjusted to 5 (mol / kg). A small amount of the adjusted slurry was sampled and the pH when diluted 10 times with water was 1
It was 1.7. Then, the latter-stage polymerization step was started while stirring at a rotation speed of 140 RPM. That is, the temperature T ₁ = 26
Hold at 5 ° C. for 30 minutes, then quench (temperature drop to about 240 ° C.) and immediately set temperature T ₂ = 245 ° C. (ΔT = T ₁
The temperature was adjusted to −T ₂ = 20 ° C.) and kept for 4.0 hours.

Immediately after the completion of the reaction, the bottom push-up valve was opened, and all the reaction slurries were unloaded into the unloading tank. Almost no polymer remained in the autoclave. The reaction slurry was extracted from the unloading tank, and the polymer (granular) was recovered using a screen having an opening of 0.1 mm. The polymer was washed with acetone / washed with water three times, dried, and collected. The obtained polymer is a granular material having an average particle diameter of 0.8 mm and a bulk density of 0.40 (g / ml) and having good handleability, and has a melt viscosity η ^* = 4100 poise (solution viscosity η
It was a high molecular weight PAS of _inh = 0.37). Comparative Example 1 Temperature T ₁ = 26 in the second-stage polymerization step in Example 2
2. Polymerization is performed at 5 ° C., and the temperature is not lowered during the polymerization.
The reaction was continued for 0 hours. After the completion of the polymerization reaction, the push-up valve of the autoclave was opened to unload the reaction slurry, but the coarse particle polymer clogged the valve clearance, and about 25% of the polymer could not be unloaded. The unloaded slurry was post-treated in the same manner as in Example 2 to recover the polymer. The obtained polymer was coarse particles having irregular particle sizes and poor handleability. The melt viscosity η ^{* of the} polymer is 3900 poise (solution viscosity η _inh = 0.
36). Comparative Example 2 In the second-stage polymerization step in Example 2, the temperature T ₁ = 24.
Polymerization is carried out at 5 ° C, without changing the temperature during the process.
The reaction was continued for 6.0 hours. After the completion of the polymerization reaction, the push-up valve at the bottom of the autoclave was opened to unload the reaction slurry. The slurry remaining in the autoclave is
There was virtually no. The reaction slurry was extracted from the unloading tank, and the polymer (granular) was recovered using a screen having an opening of 0.1 mm. Polymer wash with acetone / water 3
Repeated times, dried and collected. However, the appearance of the obtained polymer was almost the same as that of the cleaned prepolymer before the second-stage polymerization. At the second-stage polymerization temperature T ₁ = 245 ° C., it is considered that the temperature was too low and the prepolymer did not dissolve. Example 3 A Ti-lined 200 liter autoclave equipped with a stirrer with paddle type stirring blades (bottom part: equipped with a push-up valve for clearance (clearance 10 mm)), NMP 119 kg, and water-containing Na ₂ S (solid content 45.98%) 250 In a N ₂ stream, the temperature was raised to about 203 ° C. with stirring at 140 RPM and 880 mol of water and NMP 1 were added.
9.5 kg was distilled.

Then, 247 moles of p-DCB and 3 moles of metadichlorobenzene were added to {(arylene group / NM
P) = 2.5 (mol / kg), (total water amount / NMP) =
Polymerization was carried out at 220 ° C. for 5 hours to produce a prepolymer (DCB conversion rate: 93 mol%). Immediately after cooling, the lift valve with a lower portion was opened, and all the reaction slurries were unloaded into the unloading tank.

Then, in order to remove water-soluble components such as by-produced NaCl, the reaction slurry is diluted with sufficient water,
Using a centrifugal dehydrator, the prepolymer was recovered over a long period of time. Then the prepolymer was added with Na at pH 13.1
After washing with an OH aqueous solution, washing with NMP was carried out twice to remove the attached water, and a wet cake of a cleaned prepolymer in which harmful substances were reduced was obtained. When a part of the wet cake was sampled and the dry weight thereof was calculated to calculate the recovery rate of the cleaned prepolymer, it was about 89% with respect to the charged para and metadichlorobenzene.

This cleaning prepolymer is in the form of fine powder and has a low bulk density. The solution viscosity was 50 poise.

450 g of NaOH was added to the cleaning prepolymer.
Along with the above, it was charged into the 200 liter autoclave, NMP and water were added, and (total water amount / NMP) =
10.0 (mol / kg), (total arylene group / NMP)
= 2.5 (mol / kg). PH when a small amount of the adjusted slurry is sampled and diluted 10 times with water
Was 11.7. Then, the latter-stage polymerization step was started while stirring at a rotation speed of 140 RPM. That is, the temperature T ₁ =
Hold at 265 ° C for 1.0 hour, then quench (about 24
Temperature drop to 0 ° C), immediately temperature T ₂ = 245 ° C (ΔT
= T ₁ −T ₂ = 20 ° C.) and held for 4.0 hours.

Immediately after the completion of the reaction, the bottom push-up valve was opened, and the whole reaction slurry was unloaded into the unloading tank. Almost no polymer remained in the autoclave. The reaction slurry was extracted from the unloading tank, and the polymer (granular) was recovered using a screen having an opening of 0.1 mm. The polymer was washed with acetone / washed with water three times, dried, and collected. The obtained polymer is a granular material having an average particle diameter of 0.8 mm and a bulk density of 0.41 (g / ml) and having good handleability, and has a melt viscosity η ^* = 4000 poise (solution viscosity η
It was a high molecular weight polyarylene sulfide of _inh = 0.36). Comparative Example 3 In the second-stage polymerization step in Example 3, the temperature T ₁ = 26.
2. Polymerization is performed at 5 ° C., and the temperature is not lowered during the polymerization.
The reaction was continued for 0 hours. After the completion of the polymerization reaction, the push-up valve of the autoclave was opened to unload the reaction slurry, but the coarse particle polymer blocked the valve clearance, and about 15% of the polymer could not be unloaded. The unloaded slurry was post-treated in the same manner as in Example 3 to recover the polymer. The obtained polymer was coarse particles having irregular particle sizes and poor handleability. The melt viscosity η ^{* of the} polymer is 3700 poise (solution viscosity η _inh = 0.
35). Comparative Example 4 In the second-stage polymerization step in Example 3, the temperature T ₁ = 24.
Polymerization is carried out at 5 ° C, without changing the temperature during the process.
The reaction was continued for 6.0 hours. After the completion of the polymerization reaction, the push-up valve at the bottom of the autoclave was opened to unload the reaction slurry. The slurry remaining in the autoclave is
There was virtually no. However, the polymer was in the form of fine powder and could not be separated / collected with a screen having an opening of 0.1 mm. At the second-stage polymerization temperature T ₁ = 245 ° C., it is considered that the temperature was too low and the prepolymer did not dissolve.

Therefore, the slurry was diluted with a large amount of water, the polymer was separated using a centrifugal dehydrator, and the washing with acetone / washing with water was repeated 3 times and drying to obtain a polymer. The obtained polymer has an average particle size of 0.1 or less and a bulk specific gravity of 0.2.
It is a fine powder of 2 (g / ml) with very poor handling property, and has a melt viscosity η ^* = 540 poise (solution viscosity η _inh =
It was 0.24).

[0063]

According to the present invention, an ultra-high molecular weight PAS or a high molecular weight PAS having excellent handling property (that is, in the slurry state, for example, transportation of the slurry taken out from the polymerization tank, solid-liquid separation, etc. are easy. In addition, in the dry state, it becomes possible to industrially manufacture particulate PAS having excellent free-flow characteristics in a commercial plant, and it becomes possible to prepare a high-concentration high-molecular-weight PAS prescription. As described above in the section "Means for Solving Problems", the productivity can be greatly improved.

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Claims (4)

(57) [Claims] 1. A method for obtaining a polyarylene sulfide by reacting an alkali metal sulfide with a dihaloaromatic compound in an aprotic polar organic solvent, wherein the reaction produces a prepolymer having a melt viscosity lower than a desired melt viscosity. The pre-polymerization step comprises a pre-polymerization step and a post-polymerization step of further increasing the molecular weight of the pre-polymer.
The prepolymer is separated from the reaction system by allowing the reaction to proceed until it becomes a poise, and then the prepolymer is added to the organic solvent in an aprotic polar organic solvent containing 5.5 to 15 mol of water per kg of the organic solvent. Solvent 1k
Redispersion is performed so that 0.5 to 3.5 mol of the arylene group per g coexist, and a strong alkaline state (that is, 1 with water) is used.
A method for producing a high molecular weight or ultra high molecular weight polyarylene sulfide having excellent handling properties, which comprises performing the following post-polymerization step at a pH value of a 0-fold diluted reaction solution of 9.5 or more). Second-stage polymerization step: (a) The reaction system is maintained at a temperature (T ₁ ) in the range of 257 to 290 ° C. for at least 10 minutes with stirring. (B) Next, the temperature of the reaction system is lowered to bring the reaction system to a temperature (T ₂ ) in the range of 220 to 250 ° C. at least 2.
Hold for 0 hours with stirring. (C) Then, if necessary, the reaction system is heated to 250 to 29.
Hold at a temperature (T ₃ ) in the range of 0 ° C. with stirring for a time sufficient to produce a polyarylene sulfide of the desired melt viscosity. 2. The amount of the organic solvent used in the reaction system in the second-stage polymerization step is 0.3 to 1 mol per 1 mol of the alkali metal sulfide charged.
The manufacturing method according to claim 1, which is 2 kg. 3. The polyarylene sulfide produced is a repeating unit: A polymer having as a main component, claims 1 to 3.
The production method according to any one of item 2. 4. A process according to any one of claims 1 to 3, wherein the polyarylene sulfide produced is a substantially linear polymer.