WO2020080899A1 - Method for separating and recovering polyarylene sulfide - Google Patents

Abstract

The present invention provides a method for more efficiently separating and recovering polyarylene sulfide following polymerization, the polyarylene sulfide having excellent strength, heat resistance, flame retardancy, and processability when processed into a molded product.

Description

Method for separation and recovery of polyarylene sulfide

Mutual citations with related applications

This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0125504 filed on October 19, 2018 and Korean Patent Application No. 10-2019-0129386 filed on October 17, 2019. All content disclosed in the literature is incorporated as part of this specification.

The present invention relates to a method for more efficiently separating and recovering polyarylene sulfide having excellent strength, heat resistance, flame retardancy, and processability during processing into a molded article.

Polyarylene sulfide (PAS), typified by polyphenylene sulfide (PPS), is used in metals, especially aluminum or zinc, in automobiles, electrical and electronic products, machinery, etc. due to its excellent strength, heat resistance, flame retardancy, and processability. It is widely used as a material to replace the same die casting metal. Particularly, in the case of PPS resin, since it has good fluidity, it is advantageous to use it as a compound by kneading with a filler or reinforcing agent such as glass fiber.

In general, PAS is widely known as a method for producing a sulfur source and a dihalogenated aromatic compound in a polymerization condition in the presence of an amide compound such as N-methyl pyrrolidone (NMP). Since the polymerization reaction of this production method is a desalting polycondensation mechanism, a large amount of by-products such as sodium chloride are produced. Therefore, after the polymerization reaction, a by-product removal process is required, but by-products are difficult to completely remove by-products, and commercially available PPS products contain thousands of ppm of alkali metal content. In this way, if an alkali metal salt remains in the resulting polymer, problems such as lowering of physical properties such as electrical properties occur. Therefore, if a molded article using such a PAS as a raw material is to be applied to the field of electrical and electronic components, the degradation of electrical properties due to the alkali metal in the PAS becomes a major obstacle.

Accordingly, various methods have been known until now as a method for removing by-products such as sodium chloride from the PAS component. For example, in Japanese Laid-Open Publication No. 1986-220446, reactants containing PPS obtained by reacting sodium sulfide, sodium hydroxide and p-dichlorobenzene in N-methyl-2-pyrrolidone are repeatedly washed with water and hot water. Thereafter, a method of repeating washing in ion-exchanged water after washing with an acidic aqueous solution is also described.

However, in order to remove the metal compound (by-product) generated in the reaction generation step of the PAS, in a method of removing the metal compound from the PAS by contacting the mixture containing the solid PAS and the metal compound with water and dissolving the metal compound in water, There is a disadvantage that a long-time washing of the means layer using a large amount of water to remove impurities is required, and thus a very large-scale and complicated process is required. In addition, treatment of a large amount of aqueous wastewater generated in the washing process is also necessary, and there is a problem in that the process cost and environmental load are large. On the other hand, as a method for removing by-products such as sodium chloride from these PAS components, recently, a method of filtering and separating the pas component using a vibrating mesh and passing sodium chloride together with the waste slurry is known. The sodium chloride fine powder has a disadvantage in that the separation efficiency is reduced after several filtration processes by blocking the mesh holes.

Accordingly, there is a continuing need for a process for more efficiently separating and recovering polyarylene sulfide after polymerization without minimizing separation efficiency while minimizing the scale of the entire process while minimizing energy consumption and washing costs.

The present invention is to provide a method for more efficiently separating and recovering polyarylene sulfide having excellent strength, heat resistance, flame retardancy, and processability during processing as a molded article.

The present invention also intends to provide a method for producing polyarylene sulfide comprising a recovery process as described above.

According to an embodiment of the present invention, from the mixed solution containing polyarylene sulfide particles, alkali metal halide particles, and amide-based compounds, the polyarylene sulfide particles are used by using a decanter centrifuge under 1000 rpm to 2500 rpm conditions. A method of separating and recovering polyarylene sulfide is provided, which comprises first separating and separating and removing the alkali metal halide particles.

In addition, according to another embodiment of the invention, the alkali metal hydroxide and the alkali metal hydroxide are dehydrated in a mixed solvent of water and an amide compound to perform sulfide of the alkali metal, and water and amide Preparing a sulfur source comprising a mixed solvent of the compound; Adding a dihalogenated aromatic compound and an amide compound to the reactor containing the sulfur source, and polymerizing to synthesize polyarylene sulfide particles together with alkali metal halide particles; And from the mixed solution containing the polyarylene sulfide particles, alkali metal halide particles, amide-based compound, using a decanter type centrifuge under 1000 rpm to 2500 rpm conditions, the polyarylene sulfide particles are first precipitated and then Provided is a method for producing a polyarylene sulfide comprising; sedimenting and removing alkali metal halide particles.

As described above, according to the present invention, it is possible to remove the alkali metal halide particles together with the waste liquid after first separating and separating the polyarylene sulfide particles according to the particle size difference, without deteriorating the separation efficiency due to the alkali metal halide particles. , Even if it is separated several times in succession, it has an excellent effect of efficiently separating and recovering polyarylene sulfide particles with high separation efficiency.

1 schematically shows a process diagram of recovering polyarylene sulfide in Example 1 according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a process of sedimenting and separating polyarylene sulfide particles in a decanter centrifuge according to Example 1, followed by sedimentation and removal of alkali metal halide particles.

Figure 3 is a schematic view showing a process for recovering the polyarylene sulfide of Comparative Example 1 according to the prior art.

Figure 4 is a schematic diagram showing a process for removing and recovering the polyarylene sulfide particles by filtering in the vibrating mesh according to Comparative Example 1 from the top, and removing the alkali metal halide particles through the bottom.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only to distinguish one component from another component.

In addition, the terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include", "have" or "have" are intended to indicate the presence of implemented features, numbers, steps, elements or combinations thereof, one or more other features or It should be understood that the existence or addition possibilities of numbers, steps, elements, or combinations thereof are not excluded in advance.

The present invention can be applied to various changes and may have various forms, and specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood that all modifications, equivalents, and substitutes included in the spirit and scope of the present invention are included.

Hereinafter, the present invention will be described in more detail.

The present invention provides a method for efficiently recovering polyarylene sulfide particles from a mixed solution comprising polyarylene sulfide particles and alkali metal halide particles.

In particular, the present invention provides polyarylene sulfide particles from a waste solution comprising polyarylene sulfide particles produced from a polyarylene sulfide (PAS) manufacturing process and by-product alkali metal halide particles together with an amide compound. For efficient separation, the polyarylene sulfide particles are first precipitated according to the difference in particle size using a decanter centrifugal seperator, and then the alkali metal halide particles are precipitated to separate the alkali metal halide particles. It can be removed together with the waste solution, it is characterized in that it is possible to efficiently separate and recover the polyarylene sulfide particles without lowering the separation efficiency even if separated several times in succession.

According to an embodiment of the present invention, the separation and recovery method of the polyarylene sulfide is a decanter-type centrifuge from 1000 rpm to 2500 rpm from a mixture containing polyarylene sulfide particles, alkali metal halide particles, and amide compounds. And using the conditions, separating and separating the polyarylene sulfide particles first, followed by sedimenting and removing the alkali metal halide particles.

The method of separating and recovering the polyarylene sulfide is by using a decanter centrifuge instead of a conventional vibrating mesh, and filtering and recovering the polyarylene sulfide particles by using an alkali metal halide particle. ) After the filtration process is performed several times due to clogged pores, the problem of separation efficiency is solved, and the separation efficiency is not reduced even when separated several times in succession.

Particularly, by using the decanter-type centrifuge under 1000 rpm to 2500 rpm, separating due to sedimentation due to a specific gravity difference of particles is generally not performed, but alkali metal halide particles such as sodium chloride have a high specific gravity. In spite of the difference in sedimentation rate due to the difference in particle size, the polyarylene sulfide particles are first settled and recovered.

In this way, a decanter-type centrifuge can be used under 1000 rpm to 2500 rpm so that the difference in sedimentation speed due to the difference in particle size can appear. When the decanter-type centrifugal separator is used at a rotational speed (rpm) higher than 2500 rpm, sedimentation of the alkali metal halide is accelerated to come out like polyarylene sulfide (PAS) and the separation efficiency is lowered. In addition, when the decanter-type centrifugal separator is used under a condition of less than 1000 rpm, sedimentation takes a long time and there is a problem that the amount of waste liquid in the polyarylene sulfide (PAS) increases.

At this time, the decanter-type centrifuge may be used under a temperature condition of room temperature to 180 degrees Celsius, and may be used under a pressure condition of normal pressure to 5 bar. Here, the normal temperature refers to a temperature (normal pressure, ambient temperature) or room temperature (room temperature) under atmospheric pressure conditions from about 20 ℃ to about 28 ℃, or about 22 ℃ to about 26 It can be about ℃. In addition, the normal pressure refers to a separate pressure or normal pressure without atmospheric pressure (normal pressure, atmospheric pressure) may be about 0.95 atm to about 1.1 atm, or about 0.95 bar to about 1.1 bar.

The specific type of the decanter type centrifuge that can be used in the separation and recovery process of the polyarylene sulfide according to the present invention is not particularly limited. For example, decanter-type centrifuges are generally commercially available, and these commercially available ones can be used in the present invention.

The decanter centrifugal seperator is a device capable of separating a liquid-liquid or liquid-based mixture by sedimentation, dehydration, or concentration using centrifugal force. However, in general, decanter-type centrifuges are known to segregate and separate particles having a large specific gravity according to specific gravity of the particles, that is, density difference. However, in the present invention, the decanter-type centrifugal separator is driven under the optimized conditions, and sedimentation and separation of polyarylene sulfide particles are first performed according to particle size differences, rather than sedimentation separation due to specific gravity differences, and then the alkali metal halide particles are precipitated and removed. It is characterized by.

In particular, the present invention is intended to efficiently separate polyarylene sulfide particles from polyarylene sulfide particles generated from a polyarylene sulfide (PAS) manufacturing process and waste liquids containing various inorganic salts and impurities. . Accordingly, the mixed solution introduced into the decanter-type centrifugal separator may be a waste solution generated from a synthesis process or a washing process of polyarylene sulfide or a mixture thereof, polyarylene sulfide particles, alkali metal halide particles, and amide compounds Along with water or sodium hydroxide (NaOH), sodium acetate (NaOAc), sodium sulfide (Na ₂ S), sodium hydrogen sulfide (sodium hydrosulfide, NaSH), and p-dichlorobenzene It may further include one or more selected from the group.

Here, specific examples of the polyarylene sulfide particles include polyphenylene sulfide (PPS).

The polyarylene sulfide particles may have a particle size of 100 μm to 2000 μm, or 150 μm to 1800 μm.

As an example, the polyarylene sulfide particle size may be measured using a standard mesh seive of a process standard having various sieve pore sizes such as 100 μm, 40 μm, or 10 μm. The specific conditions for measuring the particle size of the polyarylene sulfide are not particularly limited, for example, after the polyarylene sulfide particles are about 3 hours or more at a relative humidity of 60% to 78% at about 22 ° C to 26 ° C, The particle size may be measured after storage for preferably at least about 6 hours, or at least about 9 hours, more preferably at least 15 hours, and more preferably at least 24 hours.

Further, the polyarylene sulfide particles may have a density of 1 g / cm ³ to 1.5 g / cm ³ , or 1.1 g / cm ³ to 1.45 g / cm ³ .

In one example, the density can be measured by the method of the American Society for Testing and Materials ASTM D 1505.

Meanwhile, specific examples of the alkali metal halide particles generated as a by-product together with polyarylene sulfide particles in a polyarylene sulfide (PAS) manufacturing process include sodium chloride (NaCl) and sodium iodide (NaI). And one or more of these.

The alkali metal halide particles may have a particle size of 5 μm to 30 μm, or 6 μm to 28 μm.

Further, the alkali metal halide particles may have a density of 1.9 g / cm ³ to 3 g / cm ³ , or 2 g / cm ³ to 2.8 g / cm ³ .

Here, the size and density of the alkali metal halide particles can be measured in the same way as the polyarylene sulfide particles.

In addition, the polyarylene sulfide (polyarylene sulfide, PAS) the amide-based compound included with the polyarylene sulfide particles and by-product alkali metal halide particles generated from the manufacturing process by centrifuging the slurry coming out after polymerization, polymerization Solvents usable in the process may be included. Specific examples of such amide compounds include amide compounds such as N, N-dimethylformamide or N, N-dimethylacetamide; Pyrrolidone compounds such as N-methyl-2-pyrrolidone (NMP) or N-cyclohexyl-2-pyrrolidone; Caprolactam compounds such as N-methyl-ε-caprolactam; Imidazolidinone compounds such as 1,3-dialkyl-2-imidazolidinone; Urea compounds such as tetramethyl urea; Or phosphate amide compounds such as hexamethylphosphate triamide, and any one or a mixture of two or more of them can be used. Among these, the amide-based compound may be N-methyl-2-pyrrolidone (NMP), which is frequently used in a polymerization process.

Through the separation and recovery method of polyarylene sulfide as described above, the polyarylene sulfide particles are first sedimented according to the difference in particle size using a decanter-type centrifuge, and the alkali metal halide particles are precipitated to be removed together with the waste solution. It is possible to separate and collect polyarylene sulfide particles efficiently without deteriorating the separation efficiency even if separated several times in succession.

In particular, the water content of the wet cake of the polyarylene sulfide that has been separated and recovered without a separate drying process after the filtration process according to the present invention is about 45% by weight or less, about 40% by weight or less, or about 35% by weight or less The content of the alkali metal halide relative to the weight of the polyarylene sulfide in the 웻 cake of the polyarylene sulfide may be about 50% by weight or less, about 40% by weight or less, or about 30% by weight or less.

On the other hand, according to another embodiment of the invention, there is provided a method for producing polyarylene sulfide comprising a recovery process as described above.

In the method for preparing the polyarylene sulfide, dehydration of an alkali metal hydrosulfide and an alkali metal hydroxide in a mixed solvent of water and an amide compound is performed, followed by sulfide of the alkali metal, and water and amides. Preparing a sulfur source comprising a mixed solvent of the compound (step 1); Adding a dihalogenated aromatic compound and an amide compound to the reactor containing the sulfur source, and polymerizing to synthesize polyarylene sulfide particles together with alkali metal halide particles (step 2); And from the mixed solution containing the polyarylene sulfide particles, alkali metal halide particles, amide-based compound, using a decanter-type centrifugal separator under the conditions of 1000 rpm to 2500 rpm, the polyarylene sulfide particles are first sedimented and then alkali metal Characterized in that it comprises a; step of removing the precipitated halide particles (step 3).

In the method for preparing the polyarylene sulfide according to another embodiment of the present invention, each step will be described.

The first step described above is a step of preparing a sulfur source.

The sulfur source is prepared by performing dehydration of an alkali metal hydroxide, an alkali metal hydroxide in a mixed solvent of water and an amide compound. Accordingly, the sulfur source may include a mixed solvent of water and an amide compound remaining after the dehydration reaction, together with the sulfide of the alkali metal produced by the reaction of the alkali metal hydroxide and the hydroxide of the alkali metal.

The sulfide of the alkali metal may be determined according to the type of the alkali metal hydrosulfide used in the reaction, and specific examples thereof include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide or cesium sulfide, and any one of them or Mixtures of two or more can be included.

When preparing a sulfur source by reaction of the alkali metal hydroxide and the hydroxide of the alkali metal, specific examples of the alkali metal hydrosulfide include sodium hydrogen sulfide, sodium hydrogen sulfide, potassium hydrogen sulfide, rubidium hydrogen sulfide, or cesium hydrogen sulfide. have. Any one or a mixture of two or more of these may be used, and anhydrides or hydrates of these may also be used.

In addition, specific examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, or cesium hydroxide, and any one or a mixture of two or more thereof may be used. The hydroxide of the alkali metal may be used in an equivalent ratio of 0.90 to 2.0, more specifically in an equivalent ratio of 1.0 to 1.5, and more specifically in an equivalent ratio of 1.0 to 1.2, per 1 equivalent of the sulfide of the alkali metal.

On the other hand, in the present invention, equivalent weight means molar equivalent weight (eq / mol).

In addition, in the production of a sulfur source by the reaction of the alkali metal hydroxide and the hydroxide of the alkali metal, an organic acid salt of an alkali metal capable of increasing the polymerization degree of polyarylene sulfide in a short time by promoting a polymerization reaction as a polymerization aid is added. Can be. Specifically, the organic acid salt of the alkali metal may be lithium acetate or sodium acetate, and any one or a mixture of two or more of them may be used. The organic acid salt of the alkali metal may be used in an equivalent ratio of 0.01 to 1.0, more specifically 0.01 to 0.8, and even more specifically 0.05 to 0.5 based on 1 equivalent of the hydrosulfide of the alkali metal.

The reaction of the alkali metal hydroxide with the alkali metal hydroxide may be performed in a mixed solvent of water and an amide compound, wherein specific examples of the amide compound are N, N-dimethylformamide or N, N -Amide compounds such as dimethylacetamide; Pyrrolidone compounds such as N-methyl-2-pyrrolidone (NMP) or N-cyclohexyl-2-pyrrolidone; Caprolactam compounds such as N-methyl-ε-caprolactam; Imidazolidinone compounds such as 1,3-dialkyl-2-imidazolidinone; Urea compounds such as tetramethyl urea; Or phosphate amide compounds such as hexamethylphosphate triamide, and any one or a mixture of two or more of them can be used. Among these, the amide-based compound may be more specifically N-methyl-2-pyrrolidone (NMP) when considering reaction efficiency and cosolvent effect as a polymerization solvent during polymerization for polyarylene sulfide production.

In addition, the water may be used in an equivalent ratio of about 1 to 8 with respect to 1 equivalent of the amide compound, more specifically about 1.5 to 5, and even more specifically about 2.5 to 5.

On the other hand, in the first step, a reactant containing an alkali metal hydrosulfide and an alkali metal hydroxide may generate sulfide of an alkali metal through dehydration. At this time, the dehydration reaction may be performed by stirring at a rate of about 100 rpm to about 500 rpm in a temperature range of about 130 ° C to 205 ° C. More specifically, it may be performed by stirring at a rate of about 100 rpm to about 300 rpm in a temperature range of about 175 ° C to 200 ° C. At this time, the time of the dehydration reaction may be performed within about 30 minutes to about 6 hours, or from about 1 hour to about 3 hours.

During the dehydration process, a solvent such as water may be removed through distillation, etc., and a part of the amide compound is discharged together with water, and some sulfur contained in the sulfur source reacts with water by heat during the dehydration process. It can be volatilized as a hydrogen sulfide gas.

On the other hand, as a result of the reaction of the alkali metal hydroxide, alkali metal hydroxide and alkali metal salt, the alkali metal sulfide is precipitated as a solid in a mixed solvent of water and an amide compound. Accordingly, when a polyarylene sulfide according to the present invention is used as a sulfur source, when a sulfur source prepared by reacting the above-mentioned alkali metal hydrosulfide with an alkali metal hydroxide is used, the molar ratio of the sulfur source is the alkali metal injected during the reaction. Let the molar ratio of the sulfides of

Subsequently, a dehydration process is performed to remove a solvent such as water in the reaction product containing the sulfide of the alkali metal produced as a result of the above-described reaction. The dehydration process can be performed according to a method well known in the art, the conditions are not greatly limited, and specific process conditions are as described above.

In addition, during the dehydration process, sulfur contained in the sulfur source reacts with water to generate hydrogen sulfide and alkali metal hydroxide, and the hydrogen sulfide produced is volatilized, so that it remains in the system after the dehydration process by hydrogen sulfide volatilized out of the system during the dehydration process. The amount of sulfur in the sulfur source can be reduced. For example, when using a sulfur source containing alkali metal hydrosulfide as a main component, the amount of sulfur remaining in the system after the dehydration process is equal to a value obtained by subtracting the molar amount of hydrogen sulfide volatilized out of the system from the molar amount of sulfur in the input sulfur source. . Accordingly, it is necessary to quantify the amount of effective sulfur contained in the sulfur source remaining in the system after the dehydration process from the amount of hydrogen sulfide volatilized out of the system. Specifically, the dehydration process may be performed until water becomes a molar ratio of 1 to 5, more specifically 1.5 to 4, and more specifically 1.75 to 3.5 with respect to 1 mole of effective sulfur. When the amount of moisture in the sulfur source is excessively reduced by the dehydration process, water can be adjusted by adding water prior to the polymerization process.

Accordingly, the sulfur source prepared by the reaction and dehydration of the alkali metal hydroxide and the alkali metal hydroxide may include a mixed solvent of water and an amide compound, together with the alkali metal sulfide, The water may be specifically included in a molar ratio of 1.75 to 3.5 with respect to 1 mole of sulfur contained in the sulfur source. Further, the sulfur source may further include an alkali metal hydroxide produced by the reaction of sulfur and water.

Meanwhile, according to an embodiment of the present invention, the second step is a step of preparing a polyarylene sulfide by polymerizing the sulfur source with a dihalogenated aromatic compound.

The dihalogenated aromatic compound usable for the production of the polyarylene sulfide is a compound in which two hydrogens in the aromatic ring are substituted with halogen atoms, and specific examples include o-dihalobenzene, m-dihalobenzene, and p-dihal Robenzene, dihalotoluene, dihalonaphthalene, dihalobiphenyl, dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenylsulfone, dihalodiphenylsulfoxide or dihalodiphenyl ketone, etc. Mixtures of two or more can be used. In the dihalogenated aromatic compound, the halogen atom may be fluorine, chlorine, bromine or iodine. Among these, p-dichlorobenzene (p-DCB) may be used when considering the effect of reducing reactivity and formation of side reactions when preparing polyarylene sulfide.

The dihalogenated aromatic compound may be added in an amount of about 0.8 to 1.2 based on 1 equivalent of the sulfur source. When it is added within the above-mentioned content range, polyarylene sulfide having excellent physical properties can be prepared without fear of a decrease in the melt viscosity of the polyarylene sulfide produced and an increase in the chlorine content present in the polyarylene sulfide. have. Considering the superiority of the improvement effect according to the sulfur source and the control amount of the dihalogenated aromatic compound, more specifically, the dihalogenated aromatic compound may be added in an equivalent weight of about 0.9 to 1.1.

In addition, before proceeding to the second step, the step of lowering the temperature of the reactor containing the sulfur source to a temperature of about 150 ℃ to about 200 ℃ to prevent the vaporization of the dihalogenated aromatic compound may be further included.

In addition, the polymerization reaction of the above-mentioned sulfur source with a dihalogenated aromatic compound is an aprotic polar organic solvent, and can be carried out in a solvent of an amide-based compound that is stable to alkali at high temperatures.

Specific examples of the amide-based compound are as described above, and when considering reaction efficiency among the exemplified compounds, more specifically, the amide-based compound is N-methyl-2-pyrrolidone (NMP) or N-cyclo It may be a pyrrolidone compound such as hexyl-2-pyrrolidone.

Since the amide compound contained in the sulfur source in the first step may act as a cosolvent, the amide compound added in the second step is a molar ratio of water (H ₂ O) to the amide compound present in the polymerization reaction system. It may be added in an amount such that the (molar ratio of water / amide compound) is about 0.85 or more.

In addition, other additives for controlling the polymerization reaction or molecular weight, such as a molecular weight modifier and a crosslinking agent, may be further added in a content within a range that does not degrade the physical properties and production yield of the final polyarylene sulfide.

The polymerization reaction of the sulfur source and the dihalogenated aromatic compound may be performed at about 200 ° C to about 300 ° C. Alternatively, it may be performed in multiple steps while changing the temperature within the above-described temperature range. Specifically, after the primary polymerization reaction at about 200 ° C or higher to less than about 250 ° C, the secondary polymerization reaction is continuously performed at a temperature higher than the temperature at the time of the primary polymerization reaction, specifically at about 250 ° C to about 300 ° C. Can be performed.

The polyarylene sulfide produced as a result of the polymerization reaction is generated in a particle form, and alkali metal halide particles are generated as a by-product together with the polyarylene sulfide particles.

The characteristics related to the polyarylene sulfide particles and alkali metal halide particles thus produced are as described above, and detailed description is omitted.

On the other hand, according to an embodiment of the present invention, the third step is a step of separating and recovering polyarylene sulfide particles from a reaction product produced as a result of the polymerization reaction.

In order to separate and recover the polyarylene sulfide particles, a mixed solution containing the polyarylene sulfide particles, alkali metal halide particles and amide compounds is introduced into a decanter type centrifuge, and the decanter type centrifuge is 1000 rpm to By operating under 2500 rpm conditions, the polyarylene sulfide particles are first sedimented and then removed by sedimentation of alkali metal halide particles.

In another embodiment of the present invention, features related to the process of separating and recovering the polyarylene sulfide particles are as described above, and detailed description is omitted.

After the separation and recovery of the polyarylene sulfide particles, washing, filtration, and drying processes may be selectively performed according to a conventional method.

The specific method for manufacturing the polyarylene sulfide may refer to Examples described later. However, the manufacturing method of polyarylene sulfide is not limited to the contents described in the present specification, and the manufacturing method may further employ the steps conventionally employed in the technical field to which the present invention pertains, and The step (s) can be changed by conventionally changeable step (s).

Hereinafter, preferred embodiments are provided to help understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the contents of the present invention are not limited thereby.

Example 1

1-1. Preparation of polyphenylene sulfide

Sodium sulfide is prepared by mixing 70% sodium hydrogen sulfide (NaSH) and sodium hydroxide (NaOH) in an equivalent ratio of 1: 1.05 to make a PPS polymer. At this time, 0.4 equivalents of sodium acetate (CH ₃ COONa) powder, 1.65 equivalents of N-methyl-2-pyrrolidone (NMP), and 4.72 equivalents of deionized water (DI water) were added to the reactor. Here, equivalent weight means molar equivalent weight (eq / mol). At this time, the solid reagent was first added and then added in the order of NMP and DI water. Then, the reactor was stirred at about 150 rpm, and dehydrated by heating to about 195 ° C for 1 hour and 40 minutes. Thereafter, the temperature of the reactor was lowered to about 175 ° C, and 1.02 times equivalent of para-dichlorobenzene (p-DCB) and 1.35 equivalents of N-methyl-2-pyrrolidone (NMP) of sodium hydrogen sulfide were added to the reactor. Was added. Thereafter, the reaction mixture is heated to about 230 ° C. for a shear reaction, reacted for about 2 hours, and then heated to about 255 ° C. for a subsequent reaction, reacted for about 2 hours, and then about 3 equivalents of distilled water is added and about 5 minutes Stir for a while. Then, 500 g of a slurry containing the resulting PPS polymer particles was obtained. The slurry contains polyarylene sulfide particles, alkali metal halide particles, and amide compounds.

1-2. Separation and recovery of polyphenylene sulfide

100 g of the slurry produced in step 1-1 was collected and filtered using a decanter type centrifuge as shown in FIG. 1 to collect and recover polyarylene sulfide by PPS wet cake. . At this time, the decanter-type centrifuge was used at room temperature and atmospheric pressure at 1000 rpm.

The time required to filter 100 g of the generated PPS slurry by repeating the above process was 0.3 hours in total, including additional time such as input, and the total amount of PPS wet cake separated and recovered was 24.5 g (water content 31). %). The NaCl content compared to PPS was about 20%.

Comparative Example 1

In performing the separation and recovery process for 100 g of the slurry produced in step 1-1 of Example 1, a vibrating mesh (see FIG. 4) is used instead of a decanter centrifuge as shown in FIG. By performing a filtration process (filtration) under normal temperature and normal pressure conditions, a polyarylene sulfide was separated and recovered in the same manner as in Example 1, except that a pps wet cake was obtained.

The time required to filter 100 g of the generated PPS slurry by repeating the above process was 0.3 hours, and the total amount of PPS wet cakes separated and recovered was 41.4 g (water content 104%). It can be seen that the NaCl content compared to PPS was about 80%, which significantly reduced the separation efficiency.

Comparative Example 2

In performing the separation and recovery process for 100 g of the slurry produced in step 1-1 of Example 1, a polyarylene was similar to Example 1, except that a decanter-type centrifuge was performed at 4000 rpm. The sulfide was collected separately.

The time required to filter 100 g of the generated PPS slurry by repeating the above process was 0.3 hours, including additional time such as input, and the total amount of PPS wet cakes separated and recovered was 40.5 g (moisture content 33 %). It can be seen that the NaCl content compared to PPS was about 52%, resulting in a reduction in separation efficiency.

Claims (10)

1. From the mixed solution containing polyarylene sulfide particles, alkali metal halide particles, and amide-based compounds, the polyarylene sulfide particles are first sedimented and separated by using a decanter-type centrifuge under 1000 rpm to 2500 rpm. A method of separating and recovering polyarylene sulfide, comprising sedimenting and removing the halide particles.
2. According to claim 1,

   The mixed solution is a waste solution produced in the process of synthesizing or washing the polyarylene sulfide,

   Method for separation and recovery of polyarylene sulfide.
3. According to claim 1,

   The polyarylene sulfide particles, the particle size is 100 ㎛ to 2000 ㎛,

   Method for separation and recovery of polyarylene sulfide.
4. According to claim 1,

   The polyarylene sulfide particles have a density of 1 g / cm ³ to 1.5 g / cm ³ ,

   Method for separation and recovery of polyarylene sulfide.
5. According to claim 1,

   The alkali metal halide particles, at least one selected from the group consisting of sodium chloride and sodium iodide,

   Method for separation and recovery of polyarylene sulfide.
6. According to claim 1,

   The alkali metal halide particles, the particle size is 5 ㎛ to 30 ㎛,

   Method for separation and recovery of polyarylene sulfide.
7. According to claim 1,

   The alkali metal halide particles, the density is 1.9 g / cm ³ to 3 g / cm ³ ,

   Method for separation and recovery of polyarylene sulfide.
8. According to claim 1,

   The amide compound is N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone, N-methyl- comprising at least one member selected from the group consisting of ε-caprolactam, 1,3-dialkyl-2-imidazolidinone, tetramethyl urea, and hexamethylphosphate triamide,

   Method for separation and recovery of polyarylene sulfide.
9. According to claim 1,

   The mixed solution further comprises at least one selected from the group consisting of sodium hydroxide, sodium acetate, sodium sulfide, sodium hydrogen sulfide, and p-dichlorobenzene,

   Method for separation and recovery of polyarylene sulfide.
10. A dehydration reaction of the alkali metal hydroxide and the alkali metal hydroxide in a mixed solvent of water and an amide compound to produce a sulfur source comprising an alkali metal sulfide and a mixed solvent of water and an amide compound ;

    Adding a dihalogenated aromatic compound and an amide compound to the reactor containing the sulfur source, and polymerizing to synthesize polyarylene sulfide particles together with alkali metal halide particles; And

    From the mixed solution containing the polyarylene sulfide particles, alkali metal halide particles, and amide-based compound, the polyarylene sulfide particles are first precipitated and separated by using a decanter-type centrifugal separator under conditions of 1000 rpm to 2500 rpm. Sedimentation and removal of the halide particles;

    The method of manufacturing a polyarylene sulfide containing.

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