A method for purifying polyphenylene sulfide and a method for producing polyphenylene sulfide

Abstract

The application discloses a kind of polyphenyl sulfide purification method and polyphenyl sulfide preparation method, the purification method includes: (1) using first polar organic solvent to wash the polyphenyl sulfide to be treated, (2) using water to wash the polyphenyl sulfide treated in step (1), (3) using second polar organic solvent to wash the polyphenyl sulfide treated in step (2), (4) using acid aqueous solution to wash the polyphenyl sulfide treated in step (3), (5) using water to wash the polyphenyl sulfide treated in step (4), first polar organic solvent and second polar organic solvent are same or different;The purification method of the application can be with relatively lower energy consumption and safer operation to realize lower sodium content, suitable for industrial scale application, can be applied in the process of preparing low-sodium polyphenyl sulfide.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method for purifying and preparing polyphenylene sulfide. Background Technology

[0002] Polyphenylene sulfide (PPS) is a novel high-performance thermoplastic resin with excellent high-temperature resistance, corrosion resistance, radiation resistance, flame retardancy, balanced physical and mechanical properties, excellent dimensional stability, and good electrical properties. It is widely used as a structural polymer material and, through filling and modification, is widely used as a specialty engineering plastic. Furthermore, it can be formulated into various functional films, coatings, and composite materials, achieving successful applications in electronics, aerospace, and automotive industries.

[0003] Currently, the preparation method of polyphenylene sulfide (PPS) usually involves dehydrating sodium hydroxide, N-methylpyrrolidone, and sodium hydrosulfide to obtain a sodium sulfide-containing mixture. This mixture is then mixed with p-dichlorobenzene and polymerized under high temperature and pressure to obtain PPS. Inevitably, PPS prepared in this way will contain some salt components such as sodium chloride. Therefore, it generally needs to be purified before application. Existing purification methods mainly include: (1) multiple water washes; (2) multiple organic solvent washes; and (3) a combination of water and organic solvent washes. However, in practice, these purification methods are difficult to effectively remove ions from the resin, or require a very large number of washes (i.e., a large amount of water and / or organic solvent) to achieve a certain effect, resulting in high costs and time consumption.

[0004] Based on the above problems, patent CN2004100405199 proposes a purification method for polyphenylene sulfide, and the process steps are as follows: (1) Purification treatment: using polar organic amide solvent and surfactant as purification treatment agents, the measured polyphenylene sulfide is placed in a reaction vessel, and then the measured polar organic amide solvent and surfactant are added and mixed. The mixture is heated to 180℃~250℃ under normal pressure and stirring for purification treatment, and the treatment time is at least 2 hours; (2) Filtration: after the purification treatment is completed, the mixture is cooled to 80~60℃, stirring is stopped, and the mixture is filtered to obtain polyphenylene sulfide filter material; (3) Washing and drying: first, the polyphenylene sulfide filter material is washed with acetone at 50~56℃, and then washed with deionized water at 80~95℃. The polyphenylene sulfide is dried to obtain high-purity polyphenylene sulfide. Although the patent claims that the sodium ion content can be less than 25 ppm after purification, the operation process not only requires ultra-high temperature treatment of 180℃~250℃, which has high requirements for equipment and energy consumption and poses a high temperature safety risk, but also requires the washing acetone to be at a temperature of 50~56℃ and the washing water to be at a temperature of 80~95℃, which further increases energy consumption; in addition, the sodium ion content needs to be further reduced. Summary of the Invention

[0005] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide an improved method for purifying polyphenylene sulfide with lower sodium content with relatively lower energy consumption and safer operation.

[0006] The present invention also provides a method for preparing polyphenylene sulfide including the above-described purification method, which can prepare low-sodium polyphenylene sulfide.

[0007] To achieve the above objectives, the present invention provides a technical solution: a method for purifying polyphenylene sulfide, the purification method comprising:

[0008] (1) Wash the polyphenylene sulfide to be treated with a first polar organic solvent;

[0009] (2) Wash the polyphenylene sulfide treated in step (1) with water;

[0010] (3) Wash the polyphenylene sulfide treated in step (2) with a second polar organic solvent;

[0011] (4) Wash the polyphenylene sulfide treated in step (3) with an aqueous acid solution;

[0012] (5) Wash the polyphenylene sulfide treated in step (4) with water;

[0013] The first polar organic solvent may be the same as or different from the second polar organic solvent.

[0014] According to some preferred and specific aspects of the present invention, in steps (1)-(5), the washing of each washing liquid with its corresponding polyphenylene sulfide to be treated includes: mixing and dispersing each washing liquid with its corresponding polyphenylene sulfide to be treated, selectively under stirring conditions, and filtering. In the present invention, the washing step does not require complex equipment; for example, a container capable of mixing each washing liquid with its corresponding polyphenylene sulfide to be treated is sufficient. Preferably, it can be equipped with a stirring mechanism to improve the dispersion effect and shorten the dispersion and mixing time.

[0015] In some embodiments of the present invention, the filtration process employs a filter screen with a mesh size of 140-160 μm, preferably 145-155 μm. According to one specific aspect of the present invention, the mesh size of the filter screen is 150 μm.

[0016] According to some preferred aspects of the invention, the number of times the second polar organic solvent is used for washing is less than the number of times the first polar organic solvent is used for washing.

[0017] According to some preferred aspects of the invention, during the purification process, the number of times the water is used for washing, the number of times the first polar organic solvent is used for washing, and the number of times the aqueous solution of the acid is used for washing decreases sequentially.

[0018] According to some preferred aspects of the invention, the number of times the washing is performed with the aqueous solution of the acid is the same as the number of times the washing is performed with the second polar organic solvent.

[0019] In some embodiments of the present invention, step (1) involves washing with the first polar organic solvent approximately 1-3 times, preferably 2 times;

[0020] Step (2) involves washing with the water approximately 2-4 times, preferably 3 times;

[0021] Step (3) involves washing with the second polar organic solvent approximately 1-2 times, preferably once;

[0022] Step (4) involves washing with the aqueous solution of the acid approximately 1-2 times, preferably once;

[0023] Step (5) involves washing with the water approximately 2-4 times, preferably 3 times.

[0024] According to some preferred aspects of the present invention, the first polar organic solvent and the second polar organic solvent are each independently selected from one or more combinations of the following polar solvents:

[0025] Ketone solvents, haloalkanes solvents, haloaromatics solvents, alcohol solvents, pyridine solvents, and pyrrolidone solvents.

[0026] Furthermore, the ketone solvent is one or more combinations selected from acetone, methyl ethyl ketone, butanone, cyclopentanone, cyclohexanone, and methyl isobutyl ketone.

[0027] Furthermore, the haloalkane solvent is a chlorinated C42-hydroxyl group. 1-3 Alkyl and / or brominated C 1-3 alkyl.

[0028] Further, the halogenated aromatic hydrocarbon solvent is one or more of the following compounds: chlorinated and / or brominated: benzene, naphthalene, C 1-3 Alkyl-substituted benzene, C 1-3 Alkyl-substituted naphthalene.

[0029] Furthermore, the alcohol solvent is C 1-3 Alkyl alcohols.

[0030] Furthermore, the pyridine solvent is one or more selected from pyridine, 2-methylpyridine, 3-methylpyridine, and 4-methylpyridine.

[0031] Furthermore, the pyrrolidone solvent is one or more selected from N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, and N-hydroxyethylpyrrolidone.

[0032] According to some preferred and specific aspects of the present invention, the first polar organic solvent is a ketone solvent;

[0033] The second polar organic solvent is one or more of the following: ketone solvents, halogenated aromatic hydrocarbon solvents, pyridine solvents, and pyrrolidone solvents; preferably, the second polar organic solvent is a ketone solvent, or is composed of ketone solvents and halogenated aromatic hydrocarbon solvents, or is composed of ketone solvents and pyrrolidone solvents, or is composed of pyridine solvents and halogenated aromatic hydrocarbon solvents, or is composed of pyridine solvents and pyrrolidone solvents.

[0034] In some preferred embodiments of the present invention, the first polar organic solvent is acetone;

[0035] The second polar organic solvent is one or more combinations selected from acetone, pyridine, N-methylpyrrolidone, and chloronaphthalene; preferably, the second polar organic solvent is acetone, or is composed of pyridine and N-methylpyrrolidone, or is composed of pyridine and chloronaphthalene, or is composed of acetone and N-methylpyrrolidone, or is composed of acetone and chloronaphthalene.

[0036] According to some preferred aspects of the present invention, when the second polar organic solvent is composed of ketone solvent and halogenated aromatic hydrocarbon solvent, or is composed of ketone solvent and pyrrolidone solvent, the ketone solvent accounts for 20%-90% of the second polar organic solvent by mass percentage, preferably 50%-85%, more preferably 75%-85%.

[0037] According to some preferred aspects of the present invention, when the second polar organic solvent is composed of a pyridine solvent and a halogenated aromatic hydrocarbon solvent, or a pyridine solvent and a pyrrolidone solvent, the pyridine solvent accounts for 20%-90% of the second polar organic solvent by mass percentage, preferably 50%-85%, more preferably 75%-85%.

[0038] In some embodiments of the present invention, each washing step in steps (1) to (5) is performed at 20-60°C, preferably at 20-40°C, more preferably at 20-30°C, and even more preferably at 22-28°C. For example, it can be performed at room temperature.

[0039] In some embodiments of the present invention, in steps (1)-(5), the washing time of each washing step is 5-50 min; further, in steps (1)-(3) and (5), the washing time of each washing step is 5-20 min, preferably 8-12 min, and in step (4), the washing time of washing with an acidic aqueous solution is 30-50 min.

[0040] In some embodiments of the present invention, in steps (1) to (5), the mass of the washing liquid added in each washing step is 2-10 times, preferably 3-7 times, and more preferably 4-6 times, of the corresponding polyphenylene sulfide to be treated.

[0041] In some embodiments of the present invention, in step (4), the mass concentration of the aqueous solution of acid is 0.05%-5%, preferably 0.1%-2%.

[0042] In some embodiments of the present invention, in step (4), the acid is selected from organic acids and / or inorganic acids. Preferably, the organic acid is one or more of acetic acid, citric acid, malic acid, tartaric acid, benzoic acid and salicylic acid, and the inorganic acid is one or more of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid.

[0043] In some embodiments of the present invention, the water used for water washing can be pure water or ion-exchanged water.

[0044] In some embodiments of the present invention, after step (5), a drying step is further included, wherein the drying is carried out at 100-130°C, preferably at 115-125°C.

[0045] Another technical solution provided by the present invention: a method for preparing polyphenylene sulfide, the method comprising a step of preparing polyphenylene sulfide and a step of purifying polyphenylene sulfide; wherein the step of purifying polyphenylene sulfide adopts the above-described purification method for polyphenylene sulfide.

[0046] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0047] Based on the problems of high energy consumption and relatively high sodium ion content in the purification of polyphenylene sulfide in the prior art, the inventors of this invention, through extensive experimental research, unexpectedly discovered that the following sequence of washing with a first polar organic solvent, washing with water, washing with a second polar organic solvent, washing with an aqueous acid solution, and washing with water can not only greatly reduce the sodium content in the final polyphenylene sulfide product, but also achieve processing at room temperature without the need for high temperature, greatly reducing energy consumption and improving safety, avoiding the safety risks caused by high temperature.

[0048] Furthermore, in-depth mechanistic analysis suggests that the first polar organic solvent treatment removes most of the oligomers and other impurities, while the first water wash further removes some water-soluble impurities. Following the first water wash, washing with a second polar organic solvent stimulates the opening of the polyphenylene sulfide channels and / or promotes chain flexibility, reducing chain entanglement and enhancing end-group replacement. This significantly improves the ability to displace sodium ions during the acid washing step. Finally, combined with water washing, a low sodium content is achieved without the need for high-temperature treatment. Therefore, compared to existing technologies, this invention is more suitable for industrial-scale application. Detailed Implementation

[0049] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0050] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0051] In the following examples and comparative examples, the wet cake (polyphenylene sulfide to be treated) in step (1) was prepared by the following method: sodium hydroxide and sodium hydrosulfide were dehydrated to obtain a mixture containing sodium sulfide, and then the mixture containing sodium sulfide was mixed with p-dichlorobenzene and polymerized to obtain the polyphenylene sulfide to be treated.

[0052] Specifically, its implementation process includes:

[0053] (1) Polymerization process

[0054] 9.822 kg of N-methylpyrrolidone (hereinafter referred to as "NMP") was added to a 30 L reactor and heated to 150 °C. Then, 4.394 kg of a 42 wt% sodium hydrosulfide aqueous solution (equivalent to 33 mol using NaSH) and 2.864 kg of a 47 wt% sodium hydroxide aqueous solution (33.66 kmol) were added. The temperature inside the reactor was heated to 210 °C to carry out a dehydration reaction. The amount of hydrogen sulfide volatilized during this dehydration process was 0.01326 kg (0.3... 9 mol); using this value, the amount of sulfur source in the reactor was calculated, and the result was 32.61 mol; 4.95 kg (33.67 mol) of p-dichlorobenzene (hereinafter referred to as "pDCB") was added to the reactor (pDCB / sulfur source (molar ratio) = 1.0325), and the temperature was raised to 220°C, allowing it to react for 2 hours; then, 0.7 kg of water was added to the reactor, and the temperature was raised to 260°C, allowing it to react for 3 hours; the temperature was lowered to 120°C at 1°C / min to obtain the reaction product containing a slurry.

[0055] (2) Polymer separation process:

[0056] The reaction liquid was sieved using a 150μm (100 mesh) filter to separate it into a wet cake containing granular polymer on the filter and the components that passed through the filter.

[0057] Example 1

[0058] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0059] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0060] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0061] (3) Contact the polymer components on the residual filter screen obtained after step (2) with pyridine at room temperature, mix and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0062] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0063] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0064] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0065] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 11 ppm.

[0066] Sodium content was tested using ICP (Inductively Coupled Plasma Atomic Emission Spectrometry) (the same method was used in other examples and comparative examples below). The specific testing method included the following steps:

[0067] I. Platinum Crucible Pretreatment: For PPS samples tested for non-volatile metal elements, a platinum crucible pretreatment method was used, and a blank control was also pretreated using the same method. The procedure is as follows: a) Weigh 0.1 g of sample into a platinum crucible; b) Add 8 drops of analytical grade concentrated sulfuric acid to the platinum crucible using a dropper; c) Place the acid-treated platinum crucible on an electric furnace for carbonization for 40 min; d) After carbonization, transfer the crucible to a muffle furnace at 700℃ and calcine for 45 min; e) Remove the crucible, cool it to room temperature, add 10 mL of 1.2 mol / L hydrochloric acid, and dilute to volume with ultrapure water before proceeding with subsequent analysis.

[0068] II. Detection conditions: Plasma power 1300W, pump speed: 30rpm; cooling gas flow rate: 12L / min.

[0069] Example 2

[0070] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0071] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0072] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0073] (3) Contact the polymer components on the residual filter screen obtained after step (2) with acetone at room temperature, which is 5 times the weight of the polymer. Mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0074] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0075] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0076] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0077] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 9 ppm.

[0078] Example 3

[0079] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0080] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0081] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0082] (3) Contact the polymer components on the residual filter screen obtained after step (2) with N-methylpyrrolidone (NMP) at room temperature, mix and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0083] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0084] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0085] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0086] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 19 ppm.

[0087] Example 4

[0088] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0089] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0090] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0091] (3) Contact the polymer component on the residual filter screen obtained after step (2) with 1-chloronaphthalene at room temperature, which is 5 times the weight of the polymer. Mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer component on the residual filter screen.

[0092] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0093] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0094] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0095] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 14 ppm.

[0096] Example 5

[0097] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0098] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0099] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0100] (3) The polymer components on the residual filter obtained after step (2) are brought into contact at room temperature with a pyridine N-methylpyrrolidone solution with a mass concentration of 20% relative to the polymer (i.e., pyridine is dispersed in N-methylpyrrolidone, and pyridine accounts for 20% of the total weight of the two), mixed, stirred and washed for 10 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0101] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0102] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0103] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0104] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 8 ppm.

[0105] Example 6

[0106] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0107] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0108] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0109] (3) The polymer components on the residual filter obtained after step (2) are brought into contact at room temperature with a pyridine N-methylpyrrolidone solution with a mass concentration of 50% relative to the polymer (i.e., pyridine is dispersed in N-methylpyrrolidone, and pyridine accounts for 50% of the total weight of the two), mixed, stirred and washed for 10 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0110] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0111] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0112] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0113] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 5 ppm.

[0114] Example 7

[0115] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0116] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0117] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0118] (3) The polymer components on the residual filter obtained after step (2) are brought into contact at room temperature with an N-methylpyrrolidone solution of pyridine with a mass concentration of 80% relative to the polymer (i.e., pyridine is dispersed in N-methylpyrrolidone, and pyridine accounts for 80% of the total weight of the two), mixed, stirred and washed for 10 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0119] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0120] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0121] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0122] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0123] Example 8

[0124] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0125] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0126] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0127] (3) Contact the polymer component on the residual filter obtained after step (2) with a 1-chloronaphthalene solution of pyridine with a mass concentration of 80% relative to the polymer at room temperature (i.e., pyridine is dispersed in 1-chloronaphthalene, and pyridine accounts for 80% of the total weight of the two), mix, stir and wash for 10 minutes, and then sieve with a filter with a mesh size of 150 μm to recover the polymer component on the residual filter.

[0128] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0129] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0130] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0131] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0132] Example 9

[0133] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0134] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0135] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0136] (3) The polymer components on the residual filter obtained after step (2) are brought into contact at room temperature with an N-methylpyrrolidone solution of acetone with a mass concentration of 80% (5 times the weight of the polymer) (i.e., acetone is dispersed in N-methylpyrrolidone, and acetone accounts for 80% of the total weight of the two), mixed, stirred and washed for 10 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0137] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0138] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0139] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0140] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0141] Example 10

[0142] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0143] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0144] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0145] (3) Contact the polymer component on the residual filter screen obtained after step (2) at room temperature with a 1-chloronaphthalene solution of acetone with a mass concentration of 80% (5 times the weight of the polymer) (i.e., acetone is dispersed in 1-chloronaphthalene, and acetone accounts for 80% of the total weight of the two), mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer component on the residual filter screen.

[0146] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0147] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0148] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0149] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0150] Example 11

[0151] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0152] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0153] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0154] (3) Contact the polymer components on the residual filter screen obtained after step (2) with acetone at room temperature, which is 5 times the weight of the polymer. Mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0155] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with a hydrochloric acid aqueous solution with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0156] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0157] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0158] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 10 ppm.

[0159] Example 12

[0160] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0161] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0162] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0163] (3) Contact the polymer components on the residual filter screen obtained after step (2) with N-methylpyrrolidone at room temperature, which is 5 times the weight of the polymer. Mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0164] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with an oxalic acid aqueous solution of 0.6 wt% at a concentration of 5 times the relative weight of the polymer, mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0165] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0166] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0167] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 12 ppm.

[0168] Example 13

[0169] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0170] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0171] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0172] (3) Contact the polymer component on the residual filter screen obtained after step (2) at room temperature with a 1-chloronaphthalene solution of acetone with a mass concentration of 80% (5 times the weight of the polymer) (i.e., acetone is dispersed in 1-chloronaphthalene, and acetone accounts for 80% of the total weight of the two), mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer component on the residual filter screen.

[0173] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with a hydrochloric acid aqueous solution with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0174] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0175] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0176] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0177] Example 14

[0178] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0179] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0180] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0181] (3) Contact the polymer component on the residual filter screen obtained after step (2) at room temperature with a 1-chloronaphthalene solution of acetone with a mass concentration of 80% (5 times the weight of the polymer) (i.e., acetone is dispersed in 1-chloronaphthalene, and acetone accounts for 80% of the total weight of the two), mix, stir and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer component on the residual filter screen.

[0182] (4) The polymer components on the residual filter obtained after step (3) are contacted at room temperature with a sulfuric acid aqueous solution of 0.6 wt% with a relative weight of 5 times the polymer, mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0183] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0184] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0185] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 0 ppm.

[0186] Comparative Example 1

[0187] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0188] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0189] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0190] (3) The polymer components on the residual filter obtained after step (2) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0191] (4) The polymer components on the residual filter obtained after step (3) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0192] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0193] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 107 ppm.

[0194] Comparative Example 2

[0195] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0196] (1) The wet cake is mixed with acetone at room temperature and stirred and washed for 10 minutes. Then, it is sieved through a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is then washed with acetone a second time.

[0197] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0198] (3) The polymer components on the residual filter obtained after step (2) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0199] (4) The polymer components on the residual filter obtained after step (3) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0200] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0201] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 100 ppm.

[0202] Comparative Example 3

[0203] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0204] (1) After mixing and washing the wet cake with acetone at room temperature for 10 minutes, use a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen; repeat the above acetone washing operation on the polymer component remaining on the filter screen.

[0205] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0206] (3) The polymer components on the residual filter obtained after step (2) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0207] (4) Contact the polymer components on the residual filter screen obtained after step (3) at room temperature with acetone at 5 times the weight of the polymer, mix and wash for 10 minutes, and then sieve with a filter screen with a mesh size of 150 μm to recover the polymer components on the residual filter screen.

[0208] (5) The polymer components on the residual filter obtained after step (4) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0209] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0210] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 55 ppm.

[0211] Comparative Example 4

[0212] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0213] (1) The wet cake was mixed and stirred with N-methylpyrrolidone at room temperature and stirred for 10 minutes. Then, it was sieved through a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen. The polymer component remaining on the filter screen was washed twice more with N-methylpyrrolidone.

[0214] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0215] (3) The polymer components on the residual filter obtained after step (2) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0216] (4) The polymer components on the residual filter obtained after step (3) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0217] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0218] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 46 ppm.

[0219] Comparative Example 5

[0220] This example provides a method for purifying polyphenylene sulfide, the purification method comprising:

[0221] (1) The wet cake was mixed with pyridine at room temperature and stirred and washed for 10 minutes. Then, it was sieved through a 150μm mesh filter to separate the polymer component remaining on the filter screen and the component that passed through the filter screen. The polymer component remaining on the filter screen was subjected to the above pyridine washing operation twice more.

[0222] (2) The polymer component obtained after the above treatment is mixed and washed with pure water at room temperature with 5 times the weight of the polymer for 10 minutes. Then, it is sieved with a filter screen with a mesh size of 150μm to separate the polymer component remaining on the filter screen and the component that passes through the filter screen. The polymer component remaining on the filter screen is washed with pure water twice more.

[0223] (3) The polymer components on the residual filter obtained after step (2) are contacted at room temperature with an aqueous solution of acetic acid with a concentration of 0.6 wt% (5 times the weight of the polymer), mixed and stirred for 40 minutes, and then screened with a filter with a mesh size of 150 μm to recover the polymer components on the residual filter.

[0224] (4) The polymer components on the residual filter obtained after step (3) are brought into contact with pure water at room temperature with 5 times the weight of the polymer. After mixing, stirring and washing for 10 minutes, the polymer components on the residual filter are screened with a 150μm mesh and then recovered. This operation is repeated twice.

[0225] The polymer components remaining on the filter screen are recovered and dried at 120°C.

[0226] The polymer recovered using the above operation was in granular form, and the sodium content was measured to be 76 ppm.

[0227] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0228] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A method for purifying polyphenylene sulfide, characterized in that, The purification method includes: (1) Wash the polyphenylene sulfide to be treated with a first polar organic solvent; (2) Wash the polyphenylene sulfide treated in step (1) with water; (3) Wash the polyphenylene sulfide treated in step (2) with a second polar organic solvent; (4) Wash the polyphenylene sulfide treated in step (3) with an aqueous acid solution; (5) Wash the polyphenylene sulfide treated in step (4) with water; Wherein, the first polar organic solvent may be the same as or different from the second polar organic solvent; The first polar organic solvent and the second polar organic solvent are each independently selected from one or more combinations of the following polar solvents: ketone solvents, haloalkanes solvents, haloaromatics solvents, alcohol solvents, pyridine solvents, and pyrrolidone solvents; In steps (1) to (5), each washing step is carried out at 20-30℃, and the mass of the washing liquid added in each washing step is 2-10 times the mass of the corresponding polyphenylene sulfide to be treated.

2. The purification method for polyphenylene sulfide according to claim 1, characterized in that, In steps (1) to (5), the washing methods for each washing liquid to wash the corresponding polyphenylene sulfide to be treated include: mixing and dispersing each washing liquid with the corresponding polyphenylene sulfide to be treated, selectively carrying out the process under stirring conditions, and filtering.

3. The purification method for polyphenylene sulfide according to claim 1, characterized in that, The number of times the second polar organic solvent is used for washing is less than the number of times the first polar organic solvent is used for washing.

4. The purification method for polyphenylene sulfide according to claim 1 or 3, characterized in that, During the purification process, the number of times the water is used for washing, the number of times the first polar organic solvent is used for washing, and the number of times the aqueous solution of the acid is used for washing decreases sequentially; and / or, the number of times the aqueous solution of the acid is used for washing is the same as the number of times the second polar organic solvent is used for washing.

5. The purification method for polyphenylene sulfide according to claim 1, characterized in that, The ketone solvent is one or a combination selected from acetone, methyl ethyl ketone, butanone, cyclopentanone, cyclohexanone, and methyl isobutyl ketone; and / or, the haloalkane solvent is a chlorinated C42-hydroxyl group. 1-3 Alkyl and / or brominated C 1-3 Alkyl; and / or, the halogenated aromatic hydrocarbon solvent is one or more of the following compounds: benzene, naphthalene, C 1-3 Alkyl-substituted benzene, C 1-3 Alkyl-substituted naphthalene; and / or, the alcohol solvent is C 1-3 Alkyl alcohols; and / or, the pyridine solvent is a combination of one or more selected from pyridine, 2-methylpyridine, 3-methylpyridine, and 4-methylpyridine; and / or, the pyrrolidone solvent is a combination of one or more selected from N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, and N-hydroxyethylpyrrolidone.

6. The purification method for polyphenylene sulfide according to claim 1 or 5, characterized in that, The first polar organic solvent is a ketone solvent; The second polar organic solvent is one or a combination of ketone solvents, halogenated aromatic hydrocarbon solvents, pyridine solvents, and pyrrolidone solvents.

7. The purification method for polyphenylene sulfide according to claim 6, characterized in that, The second polar organic solvent is a ketone solvent, or is composed of a ketone solvent and a halogenated aromatic hydrocarbon solvent, or is composed of a ketone solvent and a pyrrolidone solvent, or is composed of a pyridine solvent and a halogenated aromatic hydrocarbon solvent, or is composed of a pyridine solvent and a pyrrolidone solvent.

8. The purification method for polyphenylene sulfide according to claim 6, characterized in that, When the second polar organic solvent is composed of ketone solvents and halogenated aromatic hydrocarbon solvents, or ketone solvents and pyrrolidone solvents, the ketone solvents account for 20%-90% of the second polar organic solvent by mass percentage.

9. The purification method for polyphenylene sulfide according to claim 8, characterized in that, When the second polar organic solvent is composed of ketone solvents and halogenated aromatic hydrocarbon solvents, or ketone solvents and pyrrolidone solvents, the ketone solvents account for 50%-85% of the second polar organic solvent by mass percentage.

10. The purification method for polyphenylene sulfide according to claim 9, characterized in that, When the second polar organic solvent is composed of ketone solvents and halogenated aromatic hydrocarbon solvents, or ketone solvents and pyrrolidone solvents, the ketone solvents account for 75%-85% of the second polar organic solvent by mass percentage.

11. The purification method for polyphenylene sulfide according to claim 6, characterized in that, When the second polar organic solvent is composed of pyridine solvents and halogenated aromatic hydrocarbon solvents, or pyridine solvents and pyrrolidone solvents, the pyridine solvents account for 20%-90% of the second polar organic solvent by mass percentage.

12. The purification method for polyphenylene sulfide according to claim 11, characterized in that, When the second polar organic solvent is composed of pyridine solvents and halogenated aromatic hydrocarbon solvents, or pyridine solvents and pyrrolidone solvents, the pyridine solvents account for 50%-85% of the second polar organic solvent by mass percentage.

13. The purification method for polyphenylene sulfide according to claim 12, characterized in that, When the second polar organic solvent is composed of pyridine solvents and halogenated aromatic hydrocarbon solvents, or pyridine solvents and pyrrolidone solvents, the pyridine solvents account for 75%-85% of the second polar organic solvent by mass percentage.

14. The purification method for polyphenylene sulfide according to claim 6, characterized in that, The first polar organic solvent is acetone; The second polar organic solvent is one or more of acetone, pyridine, N-methylpyrrolidone, and chloronaphthalene.

15. The purification method for polyphenylene sulfide according to claim 14, characterized in that, The second polar organic solvent is acetone, or is composed of pyridine and N-methylpyrrolidone, or pyridine and chloronaphthalene, or acetone and N-methylpyrrolidone, or acetone and chloronaphthalene.

16. The purification method for polyphenylene sulfide according to claim 1, characterized in that, In steps (1) to (5), the washing time for each washing step is 5-50 minutes.

17. The purification method for polyphenylene sulfide according to claim 16, characterized in that, In steps (1)-(3) and (5), the washing time for each washing step is 5-20 min. In step (4), the washing time for washing with an acidic aqueous solution is 30-50 min.

18. The purification method for polyphenylene sulfide according to claim 17, characterized in that, In steps (1)-(3) and (5), the washing time for each washing step is 8-12 minutes.

19. The purification method for polyphenylene sulfide according to claim 1, characterized in that, In steps (1) to (5), the mass of the washing liquid added in each washing step is 3 to 7 times the mass of the corresponding polyphenylene sulfide to be treated.

20. The purification method for polyphenylene sulfide according to claim 19, characterized in that, In steps (1) to (5), the mass of the washing liquid added in each washing step is 4-6 times the mass of the corresponding polyphenylene sulfide to be treated.

21. The purification method for polyphenylene sulfide according to claim 1, characterized in that, In step (4), the mass concentration of the aqueous solution of acid is 0.05%-5%.

22. The purification method for polyphenylene sulfide according to claim 21, characterized in that, In step (4), the mass concentration of the aqueous solution of acid is 0.1%-2%.

23. The purification method for polyphenylene sulfide according to claim 1, characterized in that, In step (4), the acid is an organic acid and / or an inorganic acid.

24. The purification method for polyphenylene sulfide according to claim 23, characterized in that, The organic acid is selected from one or more of acetic acid, citric acid, malic acid, tartaric acid, benzoic acid and salicylic acid, and the inorganic acid is selected from one or more of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid.

25. A method for preparing polyphenylene sulfide, the method comprising a step of preparing polyphenylene sulfide and a step of purifying polyphenylene sulfide, characterized in that, The purification process for polyphenylene sulfide is performed using the purification method for polyphenylene sulfide as described in any one of claims 1-24.