Method for reducing ash content and metal ion content of sulfone polymer, and sulfone polymer prepared thereby

Abstract

The present disclosure relates to a method for reducing the ash content and metal ion content of a sulfone polymer, and a sulfone polymer prepared thereby. The method comprises: adding an aromatic diphenol monomer, a dihalogenated diphenylsulfone monomer, a catalyst and a water-carrying agent to a solvent, and performing a polymerization reaction, wherein the catalyst is one or more selected from hydroxides, carbonates and bicarbonates of sodium, potassium and cesium; stopping the polymerization reaction after the viscosity of the reaction system reaches 800-1200 mPa·s; filtering the resulting polymer solution; and adding an aqueous hydrochloric acid solution to the filtered polymer solution, wherein the mass fraction of the aqueous hydrochloric acid solution is in the range of 36% to 38%, and the addition amount of the aqueous hydrochloric acid solution relative to the addition amount of the catalyst is in the range of 2 wt% to 10 wt%. By means of the method of the present disclosure, the ash content of the sulfone polymer can be substantially reduced to 50 ppm or less, and the metal ion content thereof can be substantially reduced to 4 ppm or less.

Description

Method for reducing ash content and metal ion content of sulfone polymer and sulfone polymer prepared therefrom

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure claims priority to and the benefit of Chinese Patent Application No. 202411105894.0, filed on August 13, 2024, entitled “Method for reducing ash content and metal ion content of sulfone polymer and sulfone polymer prepared therefrom,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a method for reducing ash content and metal ion content of sulfone polymer and sulfone polymer prepared therefrom, belonging to the technical field of improving the purity and quality of sulfone polymer. BACKGROUND

[0004] Sulfone polymer (including polysulfone, i.e., bisphenol A type polysulfone, polyether sulfone, polyphenyl sulfone) is a slightly amber transparent or translucent special engineering plastic, which has a series of excellent properties such as high temperature resistance, hydrolysis resistance, low molding shrinkage, strong impact toughness, non-toxic flame retardant, etc. It is widely used in pipe components, medical devices, water treatment, mechanical and electronic fields.

[0005] The production of sulfone polymer is mainly obtained by polymerization of diphenol monomer and dichlorodiphenyl sulfone under the catalysis of alkali metal salt. After the reaction is completed, a large amount of unreacted alkali metal salt and chlorinated salt byproduct impurities are left. The presence of these impurities will have a great impact on the electrical properties, light transmittance, color of the sulfone polymer. Purifying the sulfone polymer to reduce the content of residual catalyst and byproduct metal ions is beneficial to improve the performance of the sulfone polymer product.

[0006] The main post-treatment method for the industrial production of sulfone polymer at present is water boiling method, specifically: after polymerization is completed, the polymer solution is transferred to a pulverizer to be pulverized into particles. A part of metal ions is precipitated from the polymer into water during the pulverization process, while the metal ions remaining in the sulfone polymer particles need to be treated by high-temperature water boiling for more than 4 times to purify the sulfone polymer. This purification method has the following obvious disadvantages: 1. long purification time, which increases the production cycle; 2. a large amount of wastewater produced by multiple water boiling is difficult to recover, and the treatment cost is high; 3. the process of heating water will produce a large amount of energy consumption, resulting in increased cost.

[0007] Since the metal ion content of sulfone polymer products on the market at present is relatively high, it has affected the application of sulfone polymer in the fields of medical devices, electronics, etc. Therefore, further reducing the metal ion content of sulfone polymer products and obtaining high-purity and high-quality sulfone polymer products has been a problem faced by those skilled in the art. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present disclosure aims to solve the problems existing in the prior art mentioned above, reduce the ash content and metal ion content of the sulfone polymer.

[0010] SOLUTION TO THE PROBLEM

[0011] In order to achieve the above-mentioned purpose, the present inventors have conducted in-depth research and found that: after the polymerization reaction is completed, the polymer solution is first filtered to substantially remove unreacted alkali metal salt, reaction by-products such as chlorinated salt and other solid particulate impurities, and then a specific amount of hydrochloric acid aqueous solution of a specific concentration is added to the filtrate, which can further reduce the metal ion content remaining in the sulfone polymer and further reduce the ash content, thereby improving the quality of the sulfone polymer product.

[0012] The present disclosure provides a method for reducing the ash content and metal ion content of a sulfone polymer, comprising: adding an aromatic dihydric phenol monomer, a dihalogenated diphenyl sulfone monomer, a catalyst, and a water-carrying agent to a solvent to perform a polymerization reaction, wherein the catalyst is one or more of sodium, potassium, cesium hydroxide, carbonate, bicarbonate;

[0013] After the viscosity of the reaction system reaches 800-1200 mPa·s, the polymerization reaction is stopped;

[0014] The obtained polymer solution is filtered;

[0015] A hydrochloric acid aqueous solution is added to the filtered polymer solution, the mass fraction of the hydrochloric acid aqueous solution is in the range of 36%-38%, and the addition amount of the hydrochloric acid aqueous solution is in the range of 2%-10% by weight relative to the addition amount of the catalyst;

[0016] The polymer solution treated with the hydrochloric acid aqueous solution is post-treated.

[0017] The method of the present disclosure, wherein the aromatic dihydric phenol monomer is one or more of bisphenol A, bisphenol S, 4,4'-dihydroxydiphenyl, hydroquinone, resorcinol, catechol, 4,4'-dihydroxydiphenyl ether.

[0018] The method of the present disclosure, wherein the dihalogenated diphenyl sulfone monomer is at least one of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone.

[0019] The method of the present disclosure, wherein the sulfone polymer is at least one of bisphenol A type polysulfone, polyether sulfone, and polyphenyl sulfone.

[0020] The method of the present disclosure, wherein the molar ratio of the aromatic dihydric phenolic monomer to the dihalo diphenyl sulfone monomer is 1:1; preferably, the molar ratio of the catalyst to the aromatic dihydric phenolic monomer is 1.3:1.

[0021] The method of the present disclosure, wherein the solvent is at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-vinylpyrrolidone (NVP), 1,3-dimethyl-2-imidazolidinone (DMI), sulfolane.

[0022] The method of the present disclosure, wherein the water-carrying agent is one or more of toluene, o-xylene, m-xylene, p-xylene, chlorobenzene.

[0023] The method of the present disclosure, wherein the post-treatment comprises precipitating the polymer solution in water.

[0024] The present disclosure also provides a sulfone polymer obtained by the method of the present disclosure.

[0025] Effects of the invention

[0026] Compared with the traditional high-temperature boiling method, by the method of the present disclosure, the ash content in the sulfone polymer can be greatly reduced from about 350 ppm to below 50 ppm, and the metal ion content can be greatly reduced from about 70 ppm to below 4 ppm, and can be as low as only 0.6 ppm. Since the sulfone polymer obtained by the method of the present disclosure has high purity and extremely low metal ion content, the sulfone polymer can be applied in high-end fields such as medical hemodialysis, electronics and electrical appliances, and food.

[0027] Compared with the traditional high-temperature boiling method, the method of the present disclosure can reduce the traditional purification process of 5-6 times of high-temperature and high-pressure boiling to 2-3 times of normal-temperature washing, greatly shortening the production cycle, greatly improving the production efficiency, significantly reducing the energy consumption, and greatly reducing the amount of washing water. The method of the present disclosure is simpler in process, significantly reduces the cost, and is suitable for industrial production and is environmentally friendly. DETAILED DESCRIPTION

[0028] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0029] In addition, for a better understanding of the present disclosure, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present disclosure can be practiced without certain specific details. In other instances, well-known methods, apparatuses, devices, and steps have not been described in detail since they can hinder a comprehension of the present disclosure.

[0030] Unless otherwise specified, the units used in the present specification are international standard units, and the numerical values and numerical ranges appearing in the present disclosure should be understood to include systematic errors that are inevitable in industrial production.

[0031] In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0032] In the present specification, the terms "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", and the like, refer to the specific elements (e.g., features, structures, properties, and / or characteristics) described in relation to the embodiments, which are included in at least one of the embodiments described herein, and can or can not be present in other embodiments. In addition, it should be understood that the elements can be combined in various embodiments in any suitable manner.

[0033] In the present specification, the numerical range expressed using "numerical value A ~ numerical value B" means a range including the end point numerical values A and B.

[0034] The present disclosure provides a method of reducing the ash content and metal ion content of a sulfone polymer, comprising:

[0035] adding an aromatic dihydric phenol-based monomer, a dihalogenated diphenyl sulfone-based monomer, a catalyst, and a water-carrying agent to a solvent to perform a polymerization reaction, wherein the catalyst is one or more of a hydroxide, a carbonate, and a bicarbonate of sodium, potassium, and cesium;

[0036] stopping the polymerization reaction after the viscosity of the reaction system reaches 800 ~ 1200 mPa·s;

[0037] filtering the obtained polymer solution;

[0038] adding an aqueous hydrochloric acid solution to the filtered polymer solution, the mass fraction of the aqueous hydrochloric acid solution being in the range of 36 ~ 38%, and the addition amount of the aqueous hydrochloric acid solution being in the range of 2% by weight ~ 10% by weight relative to the addition amount of the catalyst;

[0039] post-treating the polymer solution treated with the aqueous hydrochloric acid solution.

[0040] Preferably, the filtration is performed under a negative pressure, more preferably under a negative pressure in the range of -0.05 MPa to -0.02 MPa.

[0041] When the amount of the aqueous hydrochloric acid added is in the range of 2% to 10% by weight with respect to the amount of the catalyst added, the residual catalyst alkali metal salt and the phenoxide at the end of the polymer molecule chain in the polymer solution after filtration can be sufficiently reacted without causing precipitation of the sulfone polymer, and if it is lower than the lower limit, the residual catalyst alkali metal salt and the phenoxide at the end of the polymer molecule chain cannot be sufficiently reacted, and if it is higher than the upper limit, excessive water easily causes precipitation of the sulfone polymer, clogging the pipe. Preferably, the amount is in the range of 5% to 10% by weight.

[0042] Preferably, the aromatic dihydric phenol-based monomer is one or more of bisphenol A, bisphenol S, 4,4'-dihydroxydiphenyl, hydroquinone, resorcinol, catechol, 4,4'-dihydroxydiphenyl ether.

[0043] Preferably, the dihalogenated diphenyl sulfone-based monomer is at least one of 4,4'-dichlorodiphenyl sulfone, 4,4'-difluorodiphenyl sulfone.

[0044] Preferably, the molar ratio of the aromatic dihydric phenol-based monomer to the dihalogenated diphenyl sulfone-based monomer is 1:1; and preferably, the molar ratio of the catalyst to the aromatic dihydric phenol-based monomer is 1.3:1.

[0045] Preferably, the catalyst is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate.

[0046] Preferably, the solvent is at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-vinylpyrrolidone (NVP), 1,3-dimethyl-2-imidazolidinone (DMI), sulfolane.

[0047] Preferably, the water-carrying agent is one or more of toluene, o-xylene, m-xylene, p-xylene, chlorobenzene.

[0048] Preferably, the post-treatment includes precipitating the polymer solution in water.

[0049] More preferably, the polysulfone precipitated in water is pulverized, washed with water, dried, and granulated.

[0050] Preferably, the polymerization reaction is performed in the range of 160 to 230°C.

[0051] Preferably, the polymerization reaction is performed for 5 to 10 hours.

[0052] Preferably, the air in the reaction kettle is replaced by vacuumizing / nitrogen charging immediately after the aromatic dihydric phenol monomer, the dihalogenated diphenyl sulfone monomer, the catalyst, the water-carrying agent, and the solvent are added, and more preferably, the replacement is performed 3 to 5 times.

[0053] Example

[0054] The embodiments of the present disclosure will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the present disclosure and should not be regarded as limiting the scope of the present disclosure. If no specific conditions are indicated in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the reagent or instrument is indicated, it is a conventional product that can be obtained on the market.

[0055] Example 1

[0056] In a 10 L polymerization kettle, 4,4'-dichlorodiphenyl sulfone 0.6 kg, bisphenol A 0.477 kg, sodium carbonate 0.288 kg, and solvent N-methyl pyrrolidone 5 kg, and water-carrying agent m-xylene 1 kg were added. After all the raw materials were added into the reaction kettle, the reaction kettle was vacuumized to a negative pressure of -0.05 MPa, and then nitrogen was immediately introduced to make the pressure in the kettle positive. After the nitrogen replacement was repeated three times, the reaction kettle was heated to 150°C for dehydration, and then the temperature was increased to 180°C for polymerization. The polymerization time was 8 hours.

[0057] When the polymer solution reached the target viscosity of 1200 mPa·s, the heating of the polymerization kettle was stopped and the condensation system was opened to start cooling. When the temperature of the polymerization kettle decreased to 140°C, the polymer solution was transferred into a continuous vacuum filter through the kettle bottom pipeline, and the negative pressure (-0.05 MPa) generated by vacuumization was used to filter and separate most of the by-products sodium chloride, unreacted salting agent sodium carbonate, and other insoluble solid particle impurities generated during the polymerization reaction.

[0058] Then, the filtered polymer solution was transferred into a refining kettle, 0.0144 kg (5% of the mass of sodium carbonate) of 36% hydrochloric acid aqueous solution was added, and the mixture was stirred uniformly to react the hydrochloric acid with the sodium phenolate at the end of the polymer chain and sodium carbonate. The reaction time was 60 minutes.

[0059] The filtered solution treated with hydrochloric acid was injected into water to precipitate, and the polymer was pulverized using a high-speed pulverizer, and the solvent and water were removed by centrifugation. The polymer was washed with water at room temperature and centrifuged twice, and then dried to obtain a polysulfone resin product.

[0060] The ash content and metal ion impurity content of the polymer product were tested, the ash content test was performed according to GB T 9345.1-2008 Determination of ash in plastics, and the metal ion content was tested according to HG T 3944-2007 Test for metal ion content in poly (vinyl chloride) resin by ICP method.

[0061] It was detected that the polysulfone obtained in Example 1 had an ash content of 71 ppm and a sodium ion concentration of 2.4 ppm.

[0062] Example 2

[0063] In a 10 L polymerization reactor, 0.6 kg of 4,4'-dichlorodiphenyl sulfone, 0.477 kg of bisphenol A, 0.288 kg of sodium carbonate, 5 kg of solvent N-methyl pyrrolidone, and 1 kg of water-carrying agent m-xylene were added. After all the raw materials were added to the reactor, the reactor was vacuumed to a negative pressure of -0.05 MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After repeating the nitrogen replacement three times, the reactor was heated to 150°C for dehydration. After the water in the polymerization system was completely removed, the temperature was raised to 180°C for polymerization. The polymerization time was 8 h.

[0064] When the polymer solution reached the target viscosity of 1200 mPa·s, the heating of the polymerization reactor was stopped and the condensation system was opened to start cooling. When the temperature of the polymerization reactor decreased to 140°C, the polymer solution was transported into a continuous vacuum filter through the bottom pipeline. The negative pressure (-0.05 MPa) generated by vacuum pumping was used to filter and separate most of the by-products sodium chloride, the salting agent sodium carbonate, and other insoluble solid particle impurities generated during the polymerization reaction.

[0065] Then, the filtered polymer solution was transferred into a refining kettle, 0.0288 kg (10% of the mass of sodium carbonate) of 36% hydrochloric acid aqueous solution was added, and the mixture was stirred uniformly. The reaction between hydrochloric acid and the sodium phenolate at the end of the polymer molecular chain and sodium carbonate was carried out for 60 min.

[0066] The filtered solution treated with hydrochloric acid was injected into water to precipitate. The polymer was then pulverized using a high-speed pulverizer, and the solvent and water were removed by centrifugation. The polymer was washed with cold water twice and dried by centrifugation to obtain a polysulfone resin product.

[0067] The ash content and metal ion impurity content of the polymer product were tested in the same way as in Example 1.

[0068] It was detected that the polysulfone obtained in Example 2 had an ash content of 50 ppm and a sodium ion concentration of 0.9 ppm.

[0069] Example 3

[0070] In a 10L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6kg, bisphenol S 0.523kg, sodium carbonate 0.288kg, solvent sulfolane 5kg, and water-carrying agent m-xylene 1kg were added. After all the raw materials were added into the polymerization reactor, the polymerization reactor was vacuumed to a negative pressure of -0.05MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced for three times, the reactor was heated to 150℃ for dehydration. After the water in the polymerization system was completely removed, the temperature was increased to 220℃ for polymerization, and the polymerization time was 6h.

[0071] When the polymer solution reached the target viscosity of 1000mPa·s, the heating of the polymerization reactor was stopped, and the condensation system was opened to start cooling. When the temperature of the polymerization reactor decreased to 140℃, the polymer solution was transported into a continuous vacuum filter through the bottom pipeline of the reactor, and the negative pressure (-0.05MPa) generated by vacuum pumping was used to filter and separate most of the by-products sodium chloride, salting agent sodium carbonate and other insoluble solid particle impurities generated during the polymerization.

[0072] Then, the filtered polymer solution was transferred into a refining kettle, 0.0144kg (5% of the mass of sodium carbonate) of 36% hydrochloric acid aqueous solution was added, and the mixture was stirred uniformly to react the hydrochloric acid with the sodium phenolate at the end of the polymer molecular chain and sodium carbonate. The reaction time was 60min.

[0073] The filtered solution treated with hydrochloric acid was injected into water for precipitation, and the polymer was crushed by a high-speed crusher, centrifuged to remove the solvent and water, washed with normal temperature water twice, and dried by centrifugation to obtain a polymer product. The ash content and metal ion impurity content of the polymer product were tested in the same way as in Example 1.

[0074] The ash content of the polymer product obtained in Example 3 was 65ppm, and the sodium ion concentration was 2ppm.

[0075] Example 4

[0076] In a 10L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6kg, bisphenol S 0.523kg, sodium carbonate 0.288kg, solvent sulfolane 5kg, and water-carrying agent m-xylene 1kg were added. After all the raw materials were added into the polymerization reactor, the polymerization reactor was vacuumed to a negative pressure of -0.05MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced for three times, the reactor was heated to 150℃ for dehydration. After the water in the polymerization system was completely removed, the temperature was increased to 220℃ for polymerization, and the polymerization time was 6h.

[0077] When the polymer solution reaches the target viscosity of 1000 mPa-s, stop heating the polymerization reactor and open the condensing system to start cooling. When the temperature of the polymerization reactor drops to 140°C, the polymer solution is transported into the continuous vacuum filter through the bottom pipeline of the reactor. The negative pressure of -0.05 MPa generated by vacuum pumping is used to filter and separate most of the by-product salts, sodium chloride, salt-forming agent sodium carbonate, and other insoluble solid particle impurities generated during the polymerization reaction.

[0078] The filtered polymer solution is then transferred into a refining kettle, and 0.0288 kg (10% of the mass of the sodium carbonate) of 36% hydrochloric acid aqueous solution is added and stirred uniformly. The reaction between the hydrochloric acid and the sodium phenolate at the end of the polymer molecule chain and the sodium carbonate is carried out for 60 minutes.

[0079] The hydrochloric acid-treated filtrate obtained above is precipitated in water, and the polymer is pulverized using a high-speed pulverizer. After centrifugation to remove the solvent and water, the polymer is washed with normal temperature water and centrifuged twice, and then dried to obtain a polymer product. The ash content and the content of metal ion impurities of the polymer product are tested in the same manner as in Example 1.

[0080] It is detected that the ash content of the polymer of Example 4 is 42 ppm, and the sodium ion concentration is 0.6 ppm.

[0081] Example 5

[0082] In a 10 L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6 kg, 4,4'-dihydroxydiphenyl 0.389 kg, sodium carbonate 0.288 kg, solvent sulfolane 5 kg, and water removal agent m-xylene 1 kg are added. After all the raw materials are added to the reactor, the reactor is vacuumed to a negative pressure of -0.05 MPa, and then nitrogen is immediately introduced to make the pressure in the reactor positive. After repeating the nitrogen replacement three times, the reactor is heated to 150°C for dehydration. After the water in the polymerization system is completely removed, the temperature is raised to 220°C for polymerization. The polymerization time is 5 hours.

[0083] When the polymer solution reaches the target viscosity of 850 mPa-s, stop heating the polymerization reactor and open the condensing system to start cooling. When the temperature of the polymerization reactor drops to 140°C, the polymer solution is transported into the continuous vacuum filter through the bottom pipeline of the reactor. The negative pressure of -0.05 MPa generated by vacuum pumping is used to filter and separate most of the by-product salts, sodium chloride, salt-forming agent sodium carbonate, and other insoluble solid particle impurities generated during the polymerization reaction.

[0084] The filtered polymer solution was then transferred into a refining kettle, 0.0144 kg of 36% hydrochloric acid aqueous solution (5% of the mass of the sodium carbonate) was added, and stirred uniformly to react the hydrochloric acid with the sodium phenoxide at the end of the polymer chain and the sodium carbonate, and the reaction time was 60 min.

[0085] The hydrochloric acid treated filtrate obtained above was injected into water for precipitation, and the polymer was pulverized by using a high-speed pulverizer, and the solvent and water were removed by centrifugation, and then washed with normal temperature water and centrifuged twice, and dried to obtain a polymer product.

[0086] The ash content and the content of metal ion impurities of the polymer product were tested in the same manner as in Example 1.

[0087] It was detected that the ash content of the polymer of Example 5 was 70 ppm, and the sodium ion concentration was 2.6 ppm.

[0088] Example 6

[0089] In a 10 L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6 kg, 4,4'-dihydroxydiphenyl 0.389 kg, sodium carbonate 0.288 kg, solvent sulfolane 5 kg, and water removal agent m-xylene 1 kg were added. After all the raw materials were added into the reactor, the reactor was vacuumed to a negative pressure of -0.05 MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced for three times, the reactor was heated to 150°C for dehydration, and then heated to 220°C for polymerization. The polymerization time was 5 h.

[0090] When the polymer solution reached the target viscosity of 850 mPa·s, the heating of the polymerization reactor was stopped and the condensation system was opened to start cooling. When the temperature of the polymerization reactor decreased to 140°C, the polymer solution was transferred into a continuous vacuum filter through the kettle bottom pipeline, and the negative pressure of -0.05 MPa generated by vacuum pumping was used to filter and separate most of the by-products sodium chloride, the salting agent sodium carbonate and other insoluble solid particle impurities generated in the polymerization reaction.

[0091] The filtered polymer solution was then transferred into a refining kettle, 0.0288 kg of 36% hydrochloric acid aqueous solution (10% of the mass of the sodium carbonate) was added, and stirred uniformly to react the hydrochloric acid with the sodium phenoxide at the end of the polymer chain and the sodium carbonate, and the reaction time was 60 min.

[0092] The hydrochloric acid treated filtrate obtained above was injected into water for precipitation, and the polymer was pulverized by using a high-speed pulverizer, and the solvent and water were removed by centrifugation, and then washed with normal temperature water and centrifuged twice, and dried to obtain a polymer product.

[0093] The ash content and metal ion impurity content of the polymer product were tested in the same manner as in Example 1.

[0094] The polymer obtained in Example 6 was detected to have an ash content of 39 ppm and a sodium ion concentration of 0.8 ppm.

[0095] Comparative Example 1

[0096] In a 10 L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6 kg, bisphenol A 0.477 kg, sodium carbonate 0.288 kg, solvent N-methyl pyrrolidone 5 kg, and water-carrying agent m-xylene 1 kg were added. After all the raw materials were put into the reactor, the reactor was vacuumed to a negative pressure of -0.05 MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced three times, the reactor was heated to 150°C for dehydration. After the water in the polymerization system was completely removed, the temperature was raised to 180°C for polymerization, and the polymerization lasted for 8 h.

[0097] When the polymer solution reached the target viscosity of 1200 mPa·s, the bottom pipe was opened, and the polymer solution was transferred into deionized water for polymer precipitation. At the same time, the polymer was pulverized by a high-speed pulverizer and then centrifuged to remove the solvent and water. Subsequently, the polymer was transferred into a washing kettle, about 20 kg of deionized water was added, and the kettle was sealed and heated to 120°C for soaking and washing, which lasted for 3 hours. The polymer after soaking and washing was centrifuged to remove water and then transferred into the washing kettle again for soaking and washing. This process was repeated 5 times, the total water consumption for each batch of product was about 100 kg, and the total time was 15 hours. The polymer resin particles were centrifuged and dried to obtain the polymer product.

[0098] The ash content and metal ion impurity content of the polymer product were tested in the same manner as in Example 1.

[0099] The polymer obtained in Comparative Example 1 was detected to have an ash content of 350 ppm and a sodium ion concentration of 68 ppm.

[0100] Comparative Example 2

[0101] In a 10 L polymerization reactor, 4,4'-dichlorodiphenyl sulfone 0.6 kg, bisphenol A 0.477 kg, sodium carbonate 0.288 kg, solvent N-methyl pyrrolidone 5 kg, and water-carrying agent m-xylene 1 kg were added. After all the raw materials were put into the reactor, the reactor was vacuumed to a negative pressure of -0.05 MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced three times, the reactor was heated to 150°C for dehydration. After the water in the polymerization system was completely removed, the temperature was raised to 180°C for polymerization, and the polymerization lasted for 8 h.

[0102] When the polymer solution reaches the target viscosity of 1200 mPa-s, stop heating the polymerization reactor and open the condensation system to start cooling. When the temperature of the polymerization reactor drops to 140°C, transfer the polymer solution through the bottom line of the reactor into a continuous vacuum filter. Use the negative pressure of -0.05 MPa generated by vacuum pumping to filter and separate most of the by-products, such as sodium chloride, sodium carbonate, and other insoluble solid particle impurities, generated during the polymerization reaction.

[0103] Subsequently, the filtered polymer solution is injected into water for precipitation. The polymer is then pulverized, washed, centrifuged, and dried using a high-speed pulverizer to obtain the polymer product.

[0104] The ash content and metal ion impurity content of the polymer product are tested in the same manner as in Example 1.

[0105] After testing, the polymer obtained in Comparative Example 2 has an ash content of 95 ppm and a sodium ion concentration of 6.4 ppm.

[0106] Comparative Example 3

[0107] In a 10 L polymerization reactor, add 4,4'-dichlorodiphenyl sulfone 0.6 kg, bisphenol S 0.523 kg, sodium carbonate 0.288 kg, solvent sulfolane 5 kg, and water removal agent m-xylene 1 kg. After all the raw materials are added to the reactor, vacuum pump the reactor to a negative pressure of -0.05 MPa, then immediately introduce nitrogen to make the pressure in the reactor positive. Repeat the nitrogen replacement three times, then heat the reactor to 150°C for dehydration. After the water in the polymerization system is completely removed, heat the reactor to 190°C for polymerization. The polymerization time is 6 hours.

[0108] When the polymer solution reaches the target viscosity of 1000 mPa-s, open the bottom line of the reactor to transfer the polymer solution into deionized water for resin precipitation. Use a high-speed pulverizer to pulverize the polymer, then transfer it into a washing kettle. Add about 20 kg of deionized water, seal the washing kettle, heat it to 120°C, and soak for 3 hours for washing. After centrifuging the polymer to remove water, transfer it into the washing kettle again for soaking and washing. Repeat this process 5 times. The total water consumption for each batch of product is about 100 kg, and the total time is 15 hours. After centrifuging and drying the polymer particles, the polymer product is obtained.

[0109] The ash content and metal ion impurity content of the polymer product are tested in the same manner as in Example 1.

[0110] After testing, the polymer obtained in Comparative Example 3 has an ash content of 330 ppm and a sodium ion concentration of 75 ppm.

[0111] Comparative Example 4

[0112] In a 10L polymerization reactor, 0.6kg of 4,4'-dichlorodiphenyl sulfone, 0.389kg of 4,4'-dihydroxydiphenyl, 0.288kg of sodium carbonate, 5kg of solvent sulfolane, and 1kg of water-carrying agent m-xylene were added. After all the raw materials were added into the reactor, the reactor was vacuumed to a negative pressure of -0.05MPa, and then nitrogen was immediately introduced to make the pressure in the reactor positive. After the nitrogen was replaced for three times, the reactor was heated to 150°C for dehydration, and then the temperature was increased to 220°C for polymerization. The polymerization time was 5h.

[0113] When the polymer solution reached the target viscosity of 850mPa·s, the bottom pipe of the reactor was opened, and the polymer solution was transferred into deionized water for polymer precipitation. At the same time, the polymer was pulverized by a high-speed pulverizer and then centrifuged to remove the solvent and water. Subsequently, the polymer was transferred into a washing reactor, about 20kg of deionized water was added, and then the washing reactor was sealed and heated to 120°C for soaking and washing. The soaking and washing time was 3h. The polymer after soaking and washing was centrifuged to remove water and then transferred into the washing reactor for soaking and washing again. This process was repeated for 5 times. The total water consumption for each batch of product was about 100kg, and the total time was 15h. After the polymer particles were centrifuged and dried, the polymer product was obtained.

[0114] The ash content and metal ion impurity content of the polymer product were tested in the same way as in Example 1.

[0115] It was detected that the ash content of the polymer obtained in Comparative Example 4 was 310ppm, and the sodium ion concentration was 75ppm.

[0116] It can be seen from the results of Comparative Examples 1-4 and Examples 1-6 that by using the method provided by the present disclosure, i.e., filtering the polymer solution and treating the filtered polymer solution with a specific amount of a specific concentration of hydrochloric acid solution, the ash content and metal ion content of the polymer are significantly reduced.

[0117] In addition, the method of the present disclosure only needs to be washed with water twice at room temperature without multiple high-temperature water washing, which not only shortens the production cycle and improves the production efficiency, but also reduces the energy consumption and the amount of washing water.

[0118] It should be noted that although the technical solutions of the present disclosure are introduced by specific examples, those skilled in the art can understand that the present disclosure should not be limited thereto.

[0119] Having described above several embodiments of the disclosure, any modifications and variations that fall within the scope of the described embodiments are also intended to be within the scope of the disclosure. As will be apparent to those skilled in the art, some modifications and variations to the embodiments described above can be practiced while staying within the scope and spirit of the described embodiments. The foregoing description of the described embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the described embodiments to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the disclosed embodiments be limited only by the claims.

Claims

1. A method for reducing ash content and metal ion content of a sulfone polymer, comprising: adding an aromatic dihydric phenol monomer, a dihalogenated diphenyl sulfone monomer, a catalyst, and a water-carrying agent into a solvent to perform a polymerization reaction, wherein the catalyst is one or more of hydroxides, carbonates, and bicarbonates of sodium, potassium, and cesium; stopping the polymerization reaction after the viscosity of the reaction system reaches 800-1200 mPa·s; filtering the obtained polymer solution; adding an aqueous hydrochloric acid solution to the filtered polymer solution, the mass fraction of the aqueous hydrochloric acid solution being in the range of 36%-38%, and the addition amount of the aqueous hydrochloric acid solution being in the range of 2%-10% by weight relative to the addition amount of the catalyst; post-treating the polymer solution treated with the aqueous hydrochloric acid solution. 2.The method according to claim 1, wherein the aromatic dihydric phenol monomer is one or more of bisphenol A, bisphenol S, 4, 4’-dihydroxydiphenyl, hydroquinone, resorcinol, catechol, and 4, 4’-dihydroxydiphenyl ether. 3.The method according to claim 1 or 2, wherein the dihalogenated diphenyl sulfone monomer is at least one of 4, 4’-dichlorodiphenyl sulfone and 4, 4’-difluorodiphenyl sulfone. 4.The method according to claim 1 or 2, wherein the sulfone polymer is at least one of bisphenol A type polysulfone, polyether sulfone, and polyphenyl sulfone. 5.The method according to claim 1 or 2, wherein the molar ratio of the aromatic dihydric phenol monomer to the dihalogenated diphenyl sulfone monomer is 1:1; and preferably, the molar ratio of the catalyst to the aromatic dihydric phenol monomer is 1.3:

1. 6.The method according to claim 1 or 2, wherein the solvent is at least one of dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-vinylpyrrolidone (NVP), 1, 3-dimethyl-2-imidazolidinone (DMI), and sulfolane. 7.The method according to claim 1 or 2, wherein the water-carrying agent is one or more of toluene, o-xylene, m-xylene, p-xylene, and chlorobenzene. 8.The method according to claim 1 or 2, wherein the post-treatment comprises precipitating the polymer solution in water. 9.A sulfone polymer obtained by the method according to any one of claims 1-8.