JPH10195196A - Production of polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a PAS having a high rate of crystallization, a markedly high degree of whiteness and high mechanical strengths. SOLUTION: In a process for producing a polyarylene sulfide by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent, 0.1-1.5mol, per mol of the charged alkali metal sulfide, of a zinc compound is added to the polyarylene sulfide slurry after the reaction to effect its acid treatment, and at least 0.2mol, per mol of the charged alkali sulfide, of an acid or a hydrogen salt is added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polyarylene sulfide.

[0002]

2. Description of the Related Art Polyphenylene sulfide (hereinafter referred to as PP)
Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) typified by S) is excellent in heat resistance, moldability, chemical resistance, flame retardancy, dimensional stability, etc. It has been widely used as a material for electric / electronic equipment parts, automobile equipment parts, chemical equipment parts, and the like. In particular, a PAS, which is called a linear PAS and has a high molecular weight by polymerization, is characterized by having a low impurity content, good hue, and excellent thermal stability. , The utility value is high.

A method for producing the linear PAS includes:
For example, a method in which an alkali metal carboxylate is used as a polymerization aid during the polymerization reaction (Japanese Patent Publication No. 52-12240), the polymerization reaction is performed in two stages, and a large amount of water is positively added in the second stage reaction. Method (JP-A-61-73)
No. 32) or a method in which a gas phase portion of a reaction vessel is cooled during the polymerization reaction to condense a part of the gas phase in the reaction vessel and reflux the liquid phase into a liquid phase (JP-A-5-222).
196 publication).

However, PAs obtained by these methods have
When S is used for injection molding, crystallization may be insufficient depending on molding conditions. Further, in order to shorten the molding cycle, it is necessary that the crystallization speed of PAS is high, that is, the crystallization temperature _Tc is high. But,
PAS obtained by the above method has a low _Tc and cannot shorten the molding cycle.

As a method for increasing the crystallization temperature _Tc , for example, Japanese Patent Application Laid-Open No. Sho 62-48728 discloses a method in which a PAS polymer produced is separated from a polymerization reaction mixture after completion of polymerization, and then the polymer is subjected to a pH 2 reaction. Methods of treating in less than a strong acid solution are disclosed. JP-A-7-118389 discloses that an organic solvent containing an organic acid having a weight ratio of organic solvent: water in a range of 4: 1 to 1:10 and a concentration of 0.1 to 5.0% by weight. A method of acid treating PAS in a mixture of water is disclosed. However, in these methods, the PAS is treated in a low pH acid solution, and there is a disadvantage that the melt viscosity of the PAS becomes extremely low after the acid treatment. Also, the whiteness of PAS was not sufficient.

In Japanese Patent Publication No. 6-68025, an inorganic acid or an organic acid is added to a PAS slurry after polymerization, and
No. 6, a method of stirring and washing, filtering, washing with water, and drying is disclosed. The method relates to a purification method for removing impurities such as alkali metal ions in PAS. However, the PAS obtained by the above method also had a remarkably low melt viscosity of the processed PAS, and the whiteness of the PAS was not sufficient as described above. Further, in any of the above acid treatment methods, the PAS slurry obtained is separated by filtration, and the PAS is separated by repeatedly performing washing and filtration. Therefore, most of the solvents used for the polymerization are PAS
Since it is removed from and contained in the filtrate, it is necessary to recover the solvent. Since the filtrate is composed of water / polymerization solvent / by-product salt, solvent recovery is complicated and costly. On the other hand, if the solvent is not recovered, the cost is inevitably high, which is not economical. Further, when the PAS is in the form of a fine powder, there is a problem in that the filterability at the time of washing and filtering becomes low, the filtration requires a long time, and the productivity is low.

Further, the PAS is usually pale yellow in many cases, and even if a PAS having a high whiteness is obtained, coloring is likely to occur during melt molding. Therefore, special means are required to obtain a PAS molded product having high whiteness, and various means have been employed to reduce discoloration.

In Japanese Patent Laid-Open No. 60-8359, it is proposed to mix a white pigment with a PPS resin to make it white, and to compensate the decrease in mechanical strength due to the addition of the white pigment by adding an epoxy resin. ing. However, this results in high costs. Also, JP-A-3-28267 and 3-2
No. 8268 discloses a composition in which an organic phosphorus compound is added to PAS. However, there are drawbacks that the melt viscosity increases during the melt molding and decomposition gas is generated.

The present applicant has disclosed in Japanese Patent Application Laid-Open No. 7-70320 a method for producing a PAS by reacting an alkali metal sulfide with a dihaloaromatic compound in a polar aprotic solvent. Of 0.001 to 0.1 per mol of alkali metal sulfide at any time from the time of 30% to the post-treatment step of the polymerized slurry.
A method of adding moles of a zinc compound to a polymerization or post-treatment system has been disclosed. This method provides a PAS having high whiteness and high melt viscosity.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a PAS having the properties of high crystallization rate, high melt viscosity, and extremely high whiteness.

[0011]

Conventionally, an acid treatment was carried out in a low pH range as described above to increase the crystallization temperature _Tc of PAS. However, the present inventors add and treat a predetermined amount of a zinc compound as described below, and then add a predetermined amount of an acid or a hydrogen salt to carry out the acid treatment. In addition, they found that not only _Tc was improved irrespective of that, but also a significantly higher whiteness was obtained as compared with the prior art, and the present invention was completed.

That is, the present invention provides (1) a method for producing a polyarylene sulfide by reacting an alkali metal sulfide with a dihalo aromatic compound in an organic amide-based solvent, wherein the polyarylene sulfide slurry after the reaction is: 0.1 to 1.5 mol% of a zinc compound is added to 1 mol of the charged alkali metal sulfide for treatment, and then an acid or a hydrogen salt is added in an amount of 0.1 to 1 mol based on 1 mol of the charged alkali metal sulfide.
This is a method for producing polyarylene sulfide, which comprises adding an amount of 2 mol% or more and performing acid treatment.

In a preferred embodiment, (2) the zinc compound is used in an amount of 0.5 to 0.5 mol per mol of the charged alkali metal sulfide.
The method according to the above (1), which is added in an amount of 1.0 mol%,
(3) The acid or hydrogen salt is added in an amount of 0.2 to 10 mol% based on 1 mol of the charged alkali metal sulfide (1).
Or the method according to (2), wherein (4) the acid or the hydrogen salt is added in an amount of 0.5 to 6.0 mol% based on 1 mol of the charged alkali metal sulfide.
The method according to the above (1) or (2), wherein
(5) The polyarylene sulfide slurry after the treatment with an acid or a hydrogen salt is filtered, and the obtained solvent-containing filter cake is heated in a non-oxidizing atmosphere to remove the solvent. 4) The method according to any one of the above,
(6) The method according to the above (5), wherein the solvent-containing filter cake is heated at 150 to 250 ° C, (7) the method according to the above (5), wherein the solvent-containing filter cake is heated at 180 to 230 ° C.
(8) The method according to any one of the above (1) to (7), wherein after the solvent is removed, the filter cake after heating is washed with water by dispersing it in water.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of the present invention, the amount of the zinc compound added to the PAS slurry after the reaction is 1.5 mol%, preferably 1 mol, based on 1 mol of the charged alkali metal sulfide. 0.0 mol%, the lower limit is 0.1 mol%, preferably 0.5 mol%. If the amount exceeds the upper limit, the crystallization temperature _Tc cannot be increased by the subsequent addition of an acid or a hydrogen salt, and if the amount is less than the lower limit, the whiteness of the PAS cannot be increased. . The zinc compound used here is preferably soluble in the PAS slurry after the reaction, for example, zinc chloride, zinc acetate, zinc sulfate, and zinc sulfide. Of these, zinc chloride is preferably used.

In the method of the present invention, the method of treating the PAS slurry with the zinc compound is preferably as shown below.

First, a zinc compound is added to the PAS slurry generated in the PAS manufacturing process. Preferably, the zinc compound is added in the form of a solution in a small amount of water or a mixture of organic amide solvents (eg N-methylpyrrolidone) used during the water / PAS polymerization.

The treatment temperature with the zinc compound may be any temperature from room temperature to the polymerization reaction temperature of PAS, and is particularly preferably from room temperature to 220 ° C. If the treatment temperature is less than the above lower limit, the effect of the present invention cannot be sufficiently achieved. The treatment time with the zinc compound varies depending on the treatment temperature and the nature of the PAS to be treated, but is preferably 5 minutes to 24 hours, particularly preferably 20 minutes to
3 hours. If the treatment time is less than the above lower limit, the effect of the present invention cannot be sufficiently achieved as described above. The pressure is not particularly limited, and the treatment is preferably carried out by injecting a zinc compound into the reaction vessel after completion of the reaction.

In the method of the present invention, an acid or a hydrogen salt is then further added to the PAS slurry after the addition of the zinc compound.

The upper limit of the amount of the acid or hydrogen salt to be added is preferably 1 to 1 mol of the charged alkali metal sulfide.
0 mol%, more preferably 6.0 mol%, and the lower limit is 0.2 mol%, preferably 0.5 mol%. If the addition amount of the acid or hydrogen salt is less than the above lower limit, the crystallization temperature T _c
And the whiteness is low.

The acid used in the present invention is an organic acid such as a saturated fatty acid such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid or monochloroacetic acid; Saturated fatty acids, benzoic acid, phthalic acid, aromatic carboxylic acids such as salicylic acid,
Dicarboxylic acids such as oxalic acid, maleic acid, and fumaric acid, or sulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid, and the like.Examples of inorganic acids include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, and phosphoric acid. Is mentioned.
Further, as the hydrogen salt, for example, sodium hydrogen sulfate,
Disodium hydrogen phosphate, sodium hydrogen carbonate and the like may be used. For use in an actual machine, an organic acid that causes less corrosion to a metal member is preferable.

In the method of the present invention, the method of treating the PAS slurry with an acid or a hydrogen salt is preferably as described below.

First, an acid or a hydrogen salt is added to the PAS slurry after the addition of the zinc compound. At this time, when the acid or hydrogen salt is a liquid, it is added as it is or after diluting it with another solvent, preferably an organic amide solvent used in PAS polymerization (for example, N-methylpyrrolidone). When the salt is a solid, the acid is dissolved in an appropriate medium such as water or the above organic amide solvent, or a mixed solution of the above organic amide solvent and water, and then added.

The temperature of the acid treatment is preferably from room temperature to PA.
Although any temperature up to the polymerization reaction temperature of S can be adopted, it is particularly preferably room temperature to 220 ° C. When the treatment temperature is lower than the lower limit, the effects of the present invention cannot be sufficiently achieved. The acid treatment time depends on the treatment temperature and the PAS to be treated.
It is preferably 5 minutes to 24 hours, particularly preferably 20 minutes to 3 hours, although it depends on the nature of the above. If the treatment time is less than the above lower limit, the effect of the present invention cannot be sufficiently achieved. The pressure is not particularly limited, and the treatment is preferably carried out by injecting an acid or hydrogen salt into the reaction vessel after completion of the reaction.

In the present invention, PAS is added for the purpose of promoting dissociation of acid before or during addition of acid or hydrogen salt.
Water can also be added to the slurry. The amount of water added is
The upper limit is preferably 200 mol%, particularly preferably 100 mol%, and the lower limit is preferably 1.0 mol%, particularly preferably 1 mol%, per mol of the charged alkali metal sulfide.
0 mol%. Upon the addition of water, water alone may be added as it is, or water may be added to an organic amide solvent (eg, N-methylpyrrolidone) used in the polymerization of PAS.

In the present invention, after the PAS slurry obtained by treating with the above zinc compound and acid or hydrogen salt is filtered, the obtained solvent-containing filter cake is heated in a non-oxidizing gas atmosphere to remove the solvent. Is preferably removed.

For example, the PA processed as described above
The S slurry is filtered to obtain a PAS cake containing the solvent.
Next, the PAS cake is placed in a non-oxidizing atmosphere, for example, in a stream of a non-oxidizing gas such as helium, argon, hydrogen, or nitrogen, preferably in a stream of nitrogen gas, and preferably in a stream of nitrogen gas.
50 ° C., particularly preferably at a temperature of 180 to 230 ° C., preferably for 10 minutes to 24 hours, particularly preferably 1 to 10
Heated for hours. The heating is preferably performed at normal pressure to 3 atm.
It is particularly preferably carried out under normal pressure. By performing the above-described solvent removal by heating, compared to a conventional method of removing the solvent by water washing, steps such as water washing can be simplified, and the recovery rate of the solvent can be significantly improved. High cost and advantageous in cost.

The PAS from which the solvent has been removed in this way is preferably subjected to a water wash. Washing with water is preferably performed by dispersing the filter cake after the heating in water. For example, the heated PAS cake obtained as described above is preferably poured into water having a weight of 1 to 5 times, preferably at room temperature to 90 ° C., and preferably stirred and mixed for 5 minutes to 10 hours. Then, it is filtered. By repeating the stirring, mixing and filtration operations preferably 2 to 10 times,
The solvent and by-product salts attached to the PAS are removed, and the water washing is completed. By performing water washing as described above, efficient washing can be performed with a smaller amount of water than in a washing method in which water is poured into a filter cake. Further, in order to facilitate the removal of by-product salts, pressurized water washing in which the water is washed by heating to a temperature equal to or higher than the boiling point of water in a closed system can be carried out.

In the present invention, a method for producing PAS by reacting an alkali metal sulfide with a dihalo aromatic compound in an organic amide solvent is not particularly limited. For example, a method for producing a PAS by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent described in JP-B No. 45-3368, and an alkali metal carboxylic acid described in JP-B No. 52-12240. How to use acid salts,
U.S. Pat. No. 4,038,263, which uses a polymerization aid such as lithium halide described in JP-B-54-8263.
No. 719, a method using a cross-linking agent such as a polyhalo aromatic compound, and a method described in JP-B-63-33775, which uses a multi-step reaction in the presence of different amounts of water.

Preferably, in the method described in JP-A-5-222196 for producing a PAS by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent, a reaction vessel is preferably added during the reaction. By cooling the gaseous phase part of the reaction vessel, a part of the gaseous phase in the reaction vessel can be condensed, and this can be refluxed to a liquid phase. By using this method, P having a relatively high melt viscosity V ₆ can be obtained.
AS can be manufactured, and therefore, PAS having high mechanical strength such as tensile strength and impact strength can be obtained, which is preferable.

In the method, the refluxed liquid has a higher water content than the liquid bulk due to the vapor pressure difference between water and the amide solvent. The reflux liquid having a high water content forms a layer having a high water content at the upper portion of the reaction solution. As a result, a large amount of residual alkali metal sulfide (eg, Na ₂ S), alkali metal halide (eg, NaCl), oligomers, and the like are contained in the layer. In the conventional method, 2
At a high temperature of 30 ° C. or more, when the produced PAS is uniformly mixed with raw materials such as Na ₂ S and by-products, not only can a high molecular weight PAS not be obtained, but also a solution of the produced PAS can be obtained. Polymerization also occurs, and by-products of thiophenol are observed. However, in the present invention, the above disadvantageous phenomenon can be avoided by actively cooling the gas phase portion of the reaction vessel and returning a large amount of the water-rich reflux liquid to the upper part of the liquid phase so as to inhibit the reaction. It can be considered that such factors can be effectively eliminated and a high molecular weight PAS can be obtained. However, the present invention is not limited only by the effect of the above phenomenon, and a high molecular weight PAS can be obtained by various effects caused by cooling the gas phase portion.

In this method, it is not necessary to add water during the reaction as in the conventional method. However, this does not preclude the addition of water at all. However, if the operation of adding water is performed, some of the advantages of the present invention are lost. Therefore, preferably, the total water content in the polymerization reaction system is constant throughout the reaction.

The gas phase portion of the reaction vessel can be cooled either externally or internally, and can be cooled by a cooling means known per se. For example, a method of flowing a cooling medium through an internal coil installed at an upper portion in a reaction vessel, a method of flowing a cooling medium through an external coil or a jacket wrapped around an upper portion of the outside of the reaction vessel, and using a reflux condenser installed at an upper portion of the reaction vessel Methods, such as spraying water or blowing gas (air, nitrogen, etc.) on the upper part of the outside of the reaction vessel, can be considered. May be used. If the outside air temperature is relatively low (for example, normal temperature), appropriate cooling can be performed by removing a heat insulating material conventionally provided on the upper part of the reaction vessel. In the case of external cooling, water condensed on the reactor wall
The amide-based solvent mixture enters the upper layer of the liquid phase along the reaction vessel wall. Thus, the water-rich mixture accumulates at the top of the liquid phase, keeping the water content relatively high. In the case of internal cooling, the mixture condensed on the cooling surface likewise travels along the cooling device surface or the reactor wall and into the liquid phase.

On the other hand, the temperature of the liquid phase bulk is maintained at a predetermined constant temperature or controlled according to a predetermined temperature profile. 230-275 for constant temperature
It is preferred to carry out the reaction at a temperature of ° C for 0.1 to 20 hours. More preferably, the temperature is 240 to 265 ° C for 1 to 6 hours. In order to obtain a higher molecular weight PAS, it is preferable to use two or more reaction temperature profiles. This 2
When performing a step operation, the first step is preferably performed at a temperature of 195 to 240 ° C. If the temperature is low, the reaction rate is too low, which is not practical. If the temperature is higher than 240 ° C., the reaction rate is too high, so that not only a sufficiently high molecular weight PAS cannot be obtained, but also the side reaction rate is significantly increased. The end of the first phase,
The residual ratio of the dihalo aromatic compound in the polymerization reaction system is 1 mol% to 40 mol%.
It is preferable to carry out the reaction at a time point when the molar% is within the range of 3,000 to 20,000. More preferably, the residual ratio of the dihalo aromatic compound in the polymerization reaction system is in the range of 2 mol% to 15 mol%, and the molecular weight is in the range of 5,000 to 15,000. Residual rate is 40 mol%
If it exceeds 200, side reactions such as depolymerization are likely to occur in the second stage reaction, while if it is less than 1 mol%, high molecular weight P
It is hard to get AS. Thereafter, the temperature is raised, and the reaction in the final stage is preferably carried out at a reaction temperature of 240 to 270 ° C. for 1 to 10 hours. PAS with sufficiently high molecular weight at low temperature
When the temperature is higher than 270 ° C., side reactions such as depolymerization are liable to occur, making it difficult to stably obtain a high molecular weight product.

As an actual operation, first, under an inert gas atmosphere, dehydration or water addition is performed as necessary so that the water content of the polymerization system becomes a predetermined amount. The water content is preferably
0.5 to 1.39 mol per mol of alkali metal sulfide,
Particularly, it is 0.8 to 1.2 mol. If it exceeds 1.39 mol, the total amount of water added at the time of pH adjustment exceeds 1.4 mol per mol of alkali metal sulfide.
When the zinc compound is added, an operation such as flushing and adjusting the water in the system in advance occurs, which complicates the operation. 0.5
If the amount is less than the mole, the reaction rate is too high to obtain a product having a sufficient high molecular weight, and undesirable reactions such as side reactions occur.

In the case of a one-stage reaction at a constant temperature, the cooling of the gas phase during the reaction is preferably carried out from the start of the reaction, but it must be carried out at least in the course of raising the temperature to 250 ° C. or lower. In the multi-stage reaction, it is preferable to perform cooling from the first-stage reaction, but it is preferable to perform cooling at the latest after the completion of the first-stage reaction. The degree of the cooling effect is usually the most suitable index of the pressure in the reactor. The absolute value of the pressure varies depending on the characteristics of the reaction vessel, the stirring state, the amount of water in the system, the molar ratio of the dihalo aromatic compound to the alkali metal sulfide, and the like. However, when the pressure in the reaction vessel is reduced as compared with the case where the reaction vessel is not cooled under the same reaction conditions, the amount of the reflux liquid increases, which means that the temperature at the gas-liquid interface of the reaction solution decreases. It is considered that the relative degree of decrease indicates the degree of separation between a layer having a high water content and a layer having no water content. Therefore, it is preferable to perform cooling to such an extent that the internal pressure of the reaction vessel is lower than that in the case where no cooling is performed. The degree of cooling can be appropriately set by those skilled in the art according to the equipment used, operating conditions, and the like.

The organic amide solvents used in the process are known for PAS polymerization, for example N-methylpyrrolidone (NMP), N, N-dimethylformamide, N, N-dimethyl (or diethyl) acetamide , N-methyl (or ethyl) caprolactam, 1,3
-Dimethyl-2-imidazolidinone, formamide, acetamide, hexamethylphosphoramide, tetramethylurea, N, N'-ethylene-2-pyrrolidone, 2-
Pyrrolidone, ε-caprolactam, diphenylsulfone, and the like, and mixtures thereof can be used, with NMP being preferred. They all have a lower vapor pressure than water.

Alkali metal sulfides are also known, for example, lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and mixtures thereof. These hydrates and aqueous solutions may be used. Further, hydrosulfides and hydrates corresponding to these can be used after being neutralized with the corresponding hydroxides.
Inexpensive sodium sulfide is preferred.

Dihaloaromatic compounds are described in, for example,
It can be selected from those described in JP-A-5-3368, but is preferably p-dichlorobenzene. Further, a copolymer can be obtained by using one or more kinds of para-, meta- or ortho-dihalides of diphenyl ether, diphenyl sulfone or biphenyl in a small amount (20 mol% or less). For example, o-dichlorobenzene, p, p'-dichlorodiphenyl ether, m, p'-dichlorodiphenyl ether, m, m'-dichlorodiphenyl ether, p, p '
-Dichlorodiphenylsulfone, m, p'-dichlorodiphenylsulfone, m, m'-dichlorodiphenylsulfone, p, p'-dichlorobiphenyl, m, p'-dichlorobiphenyl, m, m'-dichlorobiphenyl.

In order to further increase the molecular weight of PAS,
For example, 1,3,5-trichlorobenzene, 1,2,4-
The polyhalo compound such as trichlorobenzene can be used in an amount of preferably 0.005 to 1.5 mol%, particularly preferably 0.02 to 0.75 mol%, based on 1 mol of the alkali metal sulfide.

The PAS produced by the method of the present invention is
Not only the crystallization speed is fast and the whiteness is high,
Furthermore, it has high mechanical strength. Therefore, it is suitable for injection molding.

When the PAS of the present invention is processed, conventional additives such as powdered fillers such as carbon black, calcium carbonate, silica, and titanium oxide, or carbon fibers, glass fibers, asbestos fibers, and polyaramid fibers Fibrous fillers such as can be mixed.

Further, if necessary, additives such as an antioxidant, a heat stabilizer, a lubricant, a releasing agent, and a coloring agent can be added.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0044]

EXAMPLES In the examples, the properties of PPS were measured as follows. It was measured crystallization temperature T _C by <crystallization temperature T _C> DSC. As a device, Seiko Electronics' differential scanning calorimeter S
It was measured as follows using SC / 5200. 10 mg of the sample was heated from room temperature to 320 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen stream, and then held at 320 ° C. for 5 minutes to melt. Then, the exothermic peak temperature upon cooling at a 10 ° C. / min speed to a crystallization temperature T _C. <Melt viscosity V _6> Shimadzu flow tester CFT-
Using 500C, 300 ° C, load 20kgf / cm ² ,
It is a viscosity (poise) measured after holding for 6 minutes at L / D = 10. <Hue> The whiteness (hot press L value) of the obtained polymer is
The measurement was performed as follows. Polymer at 320 ° C. for 1.5
After preheating for 1 minute at 320 ° C. for 1.5 minutes,
A disc-shaped plate was formed by pressing at 30 ° C. for 1.5 minutes at 30 kg / cm ² . The L value of this plate was measured with a colorimeter (Color Ace, manufactured by Tokyo Denshoku Co., Ltd.). <Sodium content> After the PPS powder was burned in a muffle furnace at 700 ° C, the residue was dissolved in hydrochloric acid and measured using AA-670 manufactured by Shimadzu Corporation as an atomic absorption spectrometer.

[0045]

EXAMPLE 1 15.4 Flaky sodium sulfide (60.81% by weight Na ₂ S) 15.4 was placed in a 150-liter autoclave.
00 kg and N-methyl-2-pyrrolidone (hereinafter referred to as NM
38.0 kg was charged. While stirring under a nitrogen stream, the temperature was raised to 216 ° C., and water was increased to 3.843.
kg was distilled. Then, the autoclave was closed and cooled to 180 ° C., and paradichlorobenzene (hereinafter, p
-Sometimes abbreviated as DCB) 17.640 kg and NM
P16.0 kg was charged. At a liquid temperature of 150 ° C., the pressure was increased to 1 kg / cm ² G using nitrogen gas, and the temperature was raised. The liquid temperature was raised to 260 ° C. over 4 hours, and when the liquid temperature reached 260 ° C., water sprinkling on the upper part of the autoclave was started.
The temperature was maintained for 2 hours to carry out the reaction. After the completion of the reaction, the mixture was cooled, and when the liquid temperature reached 170 ° C., zinc chloride 0.16
A solution in which 3 kg (1.0 mol% based on 1 mol of sodium sulfide) was dissolved in 0.163 kg of water was injected into an autoclave with a pressure injection pump, and stirred at 170 ° C. for 30 minutes. Then at the same temperature, 0.151 kg of oxalic acid dihydrate
NMP (1.0 mol% to 1 mol of sodium sulfide)
The solution dissolved in 0.856 kg was pressed into an autoclave by a pressure injection pump, stirred at 170 ° C. for 30 minutes, treated with an acid, and then cooled.

The obtained slurry was filtered to remove the solvent, and then the solvent-containing filter cake was heated at 220 ° C. for about 6 hours in a nitrogen stream to remove the solvent. Next, water washing and filtration were repeated 7 times on the obtained PPS powder by a conventional method.
The polymer was dried in a hot air circulation dryer at 0 ° C. for about 8 hours to obtain a white powdery polymer (P-1).

[0047]

Example 2 0.091 kg of oxalic acid dihydrate (0.6 mol% per mol of sodium sulfide) was added to 0.516 kg of NMP
Was carried out in the same manner as in Example 1 except that a solution dissolved in was added to obtain a white powdery polymer (P-2).

[0048]

EXAMPLE 3 0.227 kg of oxalic acid dihydrate (1.5 mol% based on 1 mol of sodium sulfide) was added to 1.236 kg of NMP.
The same procedure as in Example 1 was carried out except that the solution dissolved in was added, to obtain a white powdery polymer (P-3).

[0049]

Example 4 The same procedure as in Example 1 was carried out except that a solution of 0.082 kg of zinc chloride (0.5 mol% based on 1 mol of sodium sulfide) in 0.082 kg of water was added.
A white powdery polymer (P-4) was obtained.

[0050]

Example 5 0.454 kg of oxalic acid dihydrate (3.0 mol% with respect to 1 mol of sodium sulfide) was added to 6.667 kg of NMP.
The same procedure as in Example 5 was carried out except that a solution of the polymer (P-5) was added to obtain a white powdery polymer (P-5).

[0051]

Example 6 Instead of oxalic acid dihydrate, acetic acid 0.432 k
g (6.0 mol% based on 1 mol of sodium sulfide),
And the solvent-containing filter cake was dried under a pressure of 50 torr for 190 minutes.
The same operation as in Example 1 was carried out except that the solvent was removed by heating at 7 ° C. for about 7 hours to obtain a white powdery polymer (P-6).

[0052]

Example 7 A white powdery polymer (P-7) was obtained in the same manner as in Example 1 except that the stirring treatment with zinc chloride and oxalic acid dihydrate was carried out at 30 ° C.

[0053]

Comparative Example 1 A white powdery polymer (PC-1) was obtained in the same manner as in Example 1 except that zinc chloride and oxalic acid dihydrate were not added.

[0054]

Comparative Example 2 The procedure of Example 1 was repeated except that oxalic acid dihydrate was not added, and a white powdery polymer (PC-
2) was obtained.

[0055]

Comparative Example 3 A white powdery polymer (PC-3) was prepared in the same manner as in Example 1 except that zinc chloride was not added.
I got

Next, the above properties of the PPS obtained in each of the examples and comparative examples were measured.

[0057]

Comparative Example 4 The same procedure as in Example 1 was carried out except that a solution of 0.327 kg of zinc chloride (2.0 mol% based on 1 mol of sodium sulfide) dissolved in 0.327 kg of water was added.
A white powdery polymer (PC-4) was obtained.

Table 1 shows the above results.

[0059]

[Table 1] In Examples 1 to 3, the amount of acid added was changed within the scope of the present invention under the same conditions. As the amount of acid added increased, the crystallization temperature T _C increased. In addition, the whiteness tended to be slightly reduced, but did not impair the effects of the present invention. In Example 4, the amount of zinc chloride added in Example 1 was reduced within the scope of the present invention. Although the whiteness slightly decreased,
The effect of the present invention has been sufficiently achieved. The fifth embodiment is similar to the fourth embodiment.
Under the same conditions as above, the amount of acid added was increased within the scope of the present invention. T _C increased significantly. Example 6 uses acetic acid. The properties of the PPS were all good. In Example 7, a treatment with zinc chloride and oxalic acid was performed at 30 ° C. under the same conditions as in Example 1. The properties of PPS were almost the same as in Example 1.

On the other hand, in Comparative Example 1, neither treatment with zinc chloride nor oxalic acid was performed. Example 1
Compared to, T _C and whiteness was achieved remarkably bad.
Comparative Example 2 is one in which the treatment with oxalic acid was not carried out under the same conditions as in Example 1. Whiteness was good, but T
_C was extremely bad. Comparative Example 3 is one in which the treatment with zinc chloride was not performed under the same conditions as in Example 1.
Both T _C and whiteness were inferior to Example 1. In Comparative Example 4, zinc chloride was added in an amount exceeding the range of the present invention under the same conditions as in Example 1. T _C became significantly worse.

[0061]

According to the present invention, a P having a high crystallization rate, a remarkably high whiteness, and a high mechanical strength is provided.
A method for manufacturing an AS is provided.

Claims (5)

[Claims] 1. A method for producing a polyarylene sulfide by reacting an alkali metal sulfide with a dihalo aromatic compound in an organic amide solvent, wherein 1 mol of the charged alkali metal sulfide is added to the reacted polyarylene sulfide slurry. 0.1 to 1.5 mol% of a zinc compound is added to the mixture, and then an acid or a hydrogen salt is further added in an amount of 0.2 mol% or more based on 1 mol of the charged alkali metal sulfide. A method for producing polyarylene sulfide, comprising: 2. The method according to claim 1, wherein the zinc compound is added in an amount of 0.5 to 1.0 mol% based on 1 mol of the charged alkali metal sulfide. 3. The process according to claim 1, wherein the acid or hydrogen salt is added in an amount of 0.2 to 10 mol% based on 1 mol of the charged alkali metal sulfide. 4. The process according to claim 1, wherein the acid or hydrogen salt is added in an amount of 0.5 to 6.0 mol% based on 1 mol of the charged alkali metal sulfide. 5. The polyarylene sulfide slurry after the treatment with an acid or a hydrogen salt is filtered, and the obtained solvent-containing filter cake is heated under a non-oxidizing atmosphere to remove the solvent. 5. The method according to any one of 4.