Sulfone polymer capable of improving heat resistance as well as preparation method and application of sulfone polymer

Abstract

The invention provides a sulfone polymer capable of improving heat resistance and a preparation method and application thereof.The sulfone polymer is formed by conducting salifying polymerization on bisphenol monomers and 4, 4 '-dihalogen diphenyl sulfone under the condition that sulfolane serves as a solvent, and the content m of polybutadiene oligomer in the sulfone polymer is 0 lt; mlt; mlt; and 0.03%. The sulfone polymer disclosed by the invention has higher heat resistance, and can meet application requirements in high-temperature fields such as electronic industry and aerospace.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a sulfone polymer containing improved heat resistance, a preparation method thereof, and an application thereof. Background Art

[0002] Sulfone polymer resins refer to thermoplastic engineering plastics containing sulfone groups in their molecular structures. The sulfone polymers currently popular in the market mainly include polysulfone, polyphenylsulfone, and polyethersulfone. These materials all exhibit excellent thermal stability, mechanical properties, chemical corrosion resistance, and flame retardancy. At the same time, they are safe for the human body. For this reason, these sulfone polymers have been widely used in many industries such as aerospace, mechanical electronics, food, and medical treatment.

[0003] Currently, the commonly used sulfone polymer solvent systems in industry include sulfolane and N-methylpyrrolidone (NMP). Among them, sulfolane is the most commonly used reagent because of its higher boiling point and better stability. However, due to the high-temperature polymerization process and alkaline conditions, some by-products will also be generated in the sulfolane system, resulting in a decrease in the heat resistance of the sulfone polymer. For example, the 5% thermal weight loss temperature is on the low side, and the thermal expansion coefficient is on the high side, making it unable to meet the application requirements in some high-temperature fields such as the electronics industry and aerospace. Therefore, further improving the heat resistance of sulfone polymers is of great significance for broadening their application fields.

[0004] To improve the heat resistance of sulfone polymers, some patents introduce heat-resistant groups into sulfone polymers, such as CN117186406B and CN118546369A. However, this method has a complex synthesis process, high cost, and low industrialization value.

[0005] Therefore, there is still a need to develop a more practical method for improving the heat resistance of sulfone polymers in the sulfolane system. Summary of the Invention

[0006] The inventors of the present application unexpectedly found that during the synthesis of sulfone polymers in the sulfolane solvent system, part of the solvent sulfolane decomposes into butadiene, and the polymerization of butadiene generates polybutadiene oligomers. In the sulfone polymer, this polybutadiene oligomer will cause a decrease in the heat resistance of the sulfone polymer product. By controlling the content of polybutadiene oligomers in the sulfone polymer within a certain range, the heat resistance of the sulfone polymer can be significantly improved, thus completing the present invention.

[0007] The object of the present invention is to provide a sulfone polymer with improved heat resistance, and the content of polybutadiene oligomers in the sulfone polymer meets a specific range. Within this range, the sulfone polymer with the content of polybutadiene oligomers has higher heat resistance.

[0008] Another object of the present invention is to provide a preparation method for the above sulfone polymer with improved heat resistance.

[0009] Another object of the present invention is to provide an application of the above-mentioned sulfone polymer with improved heat resistance.

[0010] To achieve the above object of the present invention, the following technical solutions are adopted in the present invention:

[0011] A sulfone polymer with improved heat resistance, wherein the sulfone polymer is formed by salt-forming polymerization of a bisphenol monomer and 4,4'-dihalodiphenyl sulfone under the condition of sulfolane as a solvent, and the sulfone polymer contains a polybutadiene oligomer with a mass percentage of m, where 0 < m < 0.03%, preferably 0.01% ≤ m ≤ 0.02%.

[0012] In some specific embodiments, when the sulfone polymer is polyphenyl sulfone, its 5% thermal weight loss temperature is greater than 540 °C, and its coefficient of thermal expansion is less than 62.4 ppm / °C;

[0013] In some specific embodiments, when the sulfone polymer is polyether sulfone, its 5% thermal weight loss temperature is greater than 525 °C, and its coefficient of thermal expansion is less than 55 ppm / °C;

[0014] In some specific embodiments, when the sulfone polymer is polysulfone, its 5% thermal weight loss temperature is greater than 510 °C, and its coefficient of thermal expansion is less than 55 ppm / °C.

[0015] On the other hand, the preparation method of the aforementioned sulfone polymer with improved heat resistance includes the following steps:

[0016] 1) Add the bisphenol monomer, 4,4'-dihalodiphenyl sulfone, and salt-forming agent in proportion to the sulfolane solvent and water-carrying agent, and mix evenly;

[0017] 2) Heat to 160 - 200 °C to separate water under nitrogen protection, and then polymerize at 210 - 230 °C;

[0018] 3) After the polymerization reaches the end point, mix the cold solvent with the high-temperature reaction solution. Wait for the reaction solution to drop to 130 - 150 °C, and add a capping agent for capping. The capping time is 0.5 - 1 h;

[0019] 4) Precipitate and pulverize the capped reaction solution in water, then wash the obtained powder with a compound solvent and pure water, and dry and granulate to obtain sulfone polymer particles.

[0020] In some specific embodiments, the 4,4'-dihalodiphenyl sulfone in step 1) is selected from one or more of 4,4'-dichlorodiphenyl sulfone, 4,4'-dibromodiphenyl sulfone, and 4,4'-difluorodiphenyl sulfone, and preferably 4,4'-dichlorodiphenyl sulfone;

[0021] In some specific embodiments, the bisphenol monomer is selected from one or more of bisphenol A, bisphenol S, and biphenol;

[0022] In some specific embodiments, the salt-forming agent is selected from one or several of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, and potassium carbonate or sodium carbonate is preferred.

[0023] In some preferred embodiments, the molar ratio of the bisphenol monomer, 4,4'-dihalodiphenyl sulfone, and the salt-forming agent in step 1) is 1:0.97 - 1.03:1.05 - 2.6.

[0024] In some specific embodiments, the water-carrying agent in step 1) is selected from at least one of benzene, xylene, chlorobenzene, and mesitylene, and xylene is preferred;

[0025] In some preferred embodiments, the amount of the water-carrying agent used is 10 wt% to 40 wt% of the mass of the sulfolane solvent, and 20 wt% to 30 wt% is preferred.

[0026] In some specific embodiments, the capping agent in step 3) is a haloalkane, preferably selected from one or several of chloromethane, chloroethane, bromomethane, and bromoethane, and chloromethane is preferred;

[0027] In some preferred embodiments, the amount of the capping agent used is 0.02 - 0.08 moles of the capping agent per mole of the monomer.

[0028] In some specific embodiments, the compound solvent in step 4) is sulfolane and one or more of benzene, xylene, toluene, cyclohexane, and n-hexane, and sulfolane and toluene, n-hexane are preferred;

[0029] In some preferred embodiments, based on the mass of the compound solvent being 100%, the mass fraction of sulfolane is 10 - 40%, preferably 20% - 30%, and the mass fraction of one or more of benzene, toluene, xylene, cyclohexane, and n-hexane is 60 - 90%, preferably 70% - 80%.

[0030] In some preferred embodiments, the number of times the obtained powder is washed in the compound solvent in step 4) is 1 - 5 times, preferably 4 times, and the number of times it is washed with pure water is 1 - 2 times, preferably 2 times.

[0031] On the other hand, the application of the heat-resistant sulfone polymer described above or the heat-resistant sulfone polymer prepared by the preparation method described above in the production of molded articles, fibers, films, membranes, or foams.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1) The sulfone polymer prepared in the sulfolane system of the present invention contains polybutadiene oligomers less than 0.03 wt%, making the polymer have better heat resistance. The 5% thermal weight loss temperature can be increased by more than 15 °C, and the coefficient of thermal expansion can be reduced by about 3 ppm / °C or more.

[0034] 2) The present invention can significantly improve the heat resistance of the product only by controlling the content of polybutadiene oligomers in the sulfone polymer within a specified range. The control methods include but are not limited to washing with a compound solvent. The method is simple and easy to implement, and has good reproducibility. Detailed implementation manners

[0035] To better understand the present invention further, the following embodiments are provided by the present invention. The embodiments do not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention.

[0036] A sulfone polymer with improved heat resistance, wherein the sulfone polymer is formed by salt-forming polymerization of a bisphenol monomer and 4,4'-dihalodiphenyl sulfone under the condition of using sulfolane as a solvent. The sulfone polymer contains polybutadiene oligomers with a mass percentage of m, where 0 < m < 0.03%, such as 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, 0.016%, 0.017%, 0.018%, 0.019%, 0.02%, 0.021%, 0.022%, 0.023%, 0.024%, 0.025%, 0.026%, 0.027%, 0.028%, 0.029%, etc., and preferably 0.01% ≤ m ≤ 0.02%.

[0037] The key of the present invention lies in the discovery that polybutadiene oligomers inevitably exist in the sulfone polymer prepared in the sulfolane system, and the existence of such oligomers will affect the heat resistance of the sulfone polymer; and it is further discovered that by controlling the mass percentage content of polybutadiene oligomers in the sulfone polymer to be less than 0.03%, the heat resistance of the sulfone polymer can be significantly improved. For example, the 5% thermal weight loss temperature of polyphenylsulfone can be increased from 530 °C to 545 °C, and this improvement in heat resistance can greatly broaden its heat-resistant application scenarios.

[0038] Those skilled in the art can understand that as long as the polybutadiene oligomer in the sulfone polymer prepared by the sulfolane system is within a specific range, it can have high heat resistance, which has nothing to do with its regulation means. The control means can be, for example, the precise adjustment of the preparation process, or the use of a composite solvent for washing in post-treatment. As long as any technical means can achieve the polybutadiene oligomer within the aforementioned specific range, it should be within the scope of the present invention.

[0039] The following provides an exemplary implementation method, but does not constitute any limitation:

[0040] A method for preparing a sulfone polymer with improved heat resistance, the steps are as follows:

[0041] (1) Add bisphenol monomers, 4,4'-dihalodiphenyl sulfone, and a salifying agent in a certain proportion to a sulfolane solvent and a water-carrying agent, and mix evenly;

[0042] (2) Under nitrogen protection, heat up to an internal temperature of 160 - 200 °C in the system, such as 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, etc., for water separation, and then polymerize at a temperature of 210 - 230 °C, such as 210 °C, 220 °C, 230 °C;

[0043] (3) After the polymerization reaches the end point, mix the cold solvent (such as the sulfolane solvent in step (1) at room temperature) with the high-temperature reaction solution. Wait until the internal temperature of the system drops to 130 - 150 °C, such as 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, etc., add a certain amount of capping agent for capping, and the capping time is 0.5 - 1 h, such as 0.6 h, 0.7 h, 0.8 h, 0.9 h, etc., and the polymerization process ends;

[0044] (4) Precipitate and crush the capped reaction solution in water, then wash the obtained powder 1 - 5 times in a compound solvent, such as 1, 2, 3, 4, 5 times, preferably 4 times, and then wash it with pure water 1 - 2 times, preferably 2 times. Dry the powder in an atmospheric oven, and granulate the dried powder to obtain sulfone polymer particles.

[0045] After testing, the mass percentage content m of polybutadiene oligomer impurities in the sulfone polymer particles is 0 < m < 0.03%, such as 0.029%, 0.027%, 0.025%, 0.024%, 0.018%, 0.015%, 0.03%, 0.02%, 0.01%, 0.005%, 0.001%, 0.0001%, etc. Preferably, 0.01% ≤ m ≤ 0.02%. The 5% thermal weight loss temperature t, for polysulfone: t > 510 °C, polyphenylsulfone > 540 °C, polyethersulfone > 525 °C. In the present invention, the 5% thermal weight loss temperature refers to the temperature at which the sample mass decreases by 5%, and is often used to evaluate the thermal stability of the material. For example, using TGA testing, the specific testing method is described in detail below.

[0046] Furthermore, when controlling the mass percentage content m of polybutadiene oligomer impurities in the sulfone polymer particles to be 0 < m < 0.03%, the coefficient of thermal expansion of polyphenylsulfone is less than 62.4 ppm / °C; the coefficient of thermal expansion of polyethersulfone is less than 55 ppm / °C; the coefficient of thermal expansion of polysulfone is less than 55 ppm / °C.

[0047] A sulfone polymer described in the present invention, by controlling the mass percentage content 0 < m < 0.03% of polybutadiene oligomer impurities m in the polymer, the sulfone polymer with impurity content in this range has far higher heat resistance than products with other impurity contents.

[0048] Those skilled in the art can understand that the above preparation method does not impose any limitation on the poly polymer products of the present invention. It is only an exemplary implementation form and does not depend on this specific implementation manner. The key of the present invention lies in discovering that in the solvent condition of sulfolane, in the sulfone polymer formed by the salt-forming polymerization of bisphenol monomers and 4,4'-dihalodiphenyl sulfone, the solvent is easily hydrolyzed at high temperature, and after hydrolysis, butadiene is polymerized into polybutadiene oligomer impurities, resulting in a decrease in the heat resistance of the product. By means such as washing, controlling the mass percentage content 0 < m < 0.03% of polybutadiene oligomer impurities m in the polymer, the sulfone polymer with impurity content in this range has far higher heat resistance than products with other impurity contents.

[0049] Among them, the capping agent used in the synthesis process is a haloalkane, including one or several of methyl chloride, ethyl chloride, methyl bromide, and ethyl bromide, preferably methyl chloride. The capping agent is generally continuously added in excess. For example, it is continuously added according to the theoretical dosage of 0.02 - 0.08 moles of capping agent per mole of monomer, and the continuous time is 0.5 - 1 h.

[0050] In the present invention, the sulfone polymer includes an aromatic polysulfone obtained by polymerizing 4,4'-dihalodiphenyl sulfone and bisphenol monomers.

[0051] Among them, the 4,4'-dihalodiphenyl sulfone used in the synthesis process includes one or more of 4,4'-dichlorodiphenyl sulfone, 4,4'-dibromodiphenyl sulfone, and 4,4'-difluorodiphenyl sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0052] Among them, the salt-forming agent used in the synthesis process includes one or several of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, preferably potassium carbonate and sodium carbonate;

[0053] Among them, the molar ratio of the bisphenol monomer, 4,4'-dihalodiphenyl sulfone, and the salt-forming agent is 1:0.97 - 1.03:1.05 - 2.6, such as 1:0.97:1.05, 1:0.98:1.5, 1:1:2, 1:1.01:2.5, etc.

[0054] In step (1) of the present invention, the amount of the solvent is not particularly limited, and the amount of the added solvent is mainly adjusted according to the reaction solid content. For example, the solvent is added to make the solid content reach 20% - 50%. Among them, the solid content can be calculated by those skilled in the art based on the sulfone polymer formed by the polycondensation of the added reaction monomers (bisphenol monomer and 4,4'-dihalodiphenyl sulfone) as the solid substance.

[0055] In the present invention, operations such as salt-forming polymerization and capping are not particularly limited. Those not specifically described in the present invention can refer to the prior art. For example, the judgment of the polymerization end point and water-carrying, etc., can all be achieved by those skilled in the art using conventional technical means in the art, and will not be elaborated here.

[0056] Among them, the compound solvent is a mixed solvent of sulfolane and one or more of benzene, toluene, xylene, cyclohexane, and n-hexane. Among them, the mass ratio of sulfolane is preferably 20% - 30%, such as 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc.; the preferred mass ratio of one or more solvents of benzene, toluene, xylene, cyclohexane, and n-hexane is 70% - 80%, such as 70%, 72%, 74%, 76%, 78%, 80%,

[0057] In addition, the application of the high heat-resistant sulfone polymer described in the present invention or the high heat-resistant sulfone polymer prepared by the preparation method described in the present invention in the production of molded articles, fibers, films, membranes, or foams. In addition, sulfone polymer modified materials generated based on the products of the present invention all fall within the protection scope of the present invention.

[0058] The present invention will be further explained and illustrated below through more specific examples, but it does not constitute any limitation.

[0059] The main raw materials and test methods used in the examples of the present invention are as follows:

[0060]

[0061]

[0062] Heat resistance (5% thermal weight loss temperature) test: Analyzed by TGA according to ASTM E2550-21.

[0063] Coefficient of thermal expansion test; Analyzed by TMA according to ISO 11359 (0 - 120 °C, TD / MD).

[0064] The content of polybutadiene oligomer in the sulfone polymer was tested using the following method:

[0065] Testing instrument: Shimadzu LC-20A gel permeation chromatograph, with three chromatographic columns KD802, KD803, and KD804 connected in series, equipped with an SPD-20A ultraviolet detector (254 nm);

[0066] Conditions: Mobile phase THF, flow rate 1 mL / min, column temperature 40 °C, polystyrene standard;

[0067] Sample preparation: Dissolve the sample to be tested in THF to prepare a 1% solution, and filter it through a PTFE filter with a pore size of 0.22 μm;

[0068] Integration method: Using the area normalization method, the proportion of the area in the integration interval of 25 min - 27.5 min is the content of polybutadiene oligomer.

[0069] Example 1

[0070] (1) While stirring in a 30 L reactor, sequentially add 12000 g of sulfolane, 1862 g of 4,4-biphenol, 2929 g of 4,4'-dichlorodiphenyl sulfone, and 1272 g of sodium carbonate. After stirring evenly, conduct three nitrogen replacements; the amount of the water-carrying agent xylene is 2400 g;

[0071] (2) Then, under nitrogen protection, the reaction system is dehydrated at 180 °C for 3 h until no water is produced, and polymerized at 220 °C for 3.5 h;

[0072] (3) After the polymerization reaches the end point, add 7000 g of sulfolane for cooling and dilution. After stirring evenly, introduce 35 g of chloromethane for end-capping, and the end-capping time is 1 h;

[0073] (4) Slowly add the salt-containing reaction solution into water for precipitation, crushing, and filtration. Wash the obtained powder 4 times in a mixed solution of sulfolane and n-hexane (mass ratio 1:4) at 95 °C, then transfer it to pure water for washing 2 times, centrifuge and dehydrate to obtain the powder, and dry it at 150 °C for 12 h to obtain the powder.

[0074] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer powder is 0.028%, the 5% thermal weight loss temperature is 545 °C (polyphenyl sulfone), and the coefficient of thermal expansion is 59.5 ppm / °C.

[0075] Example 2

[0076] (1) While stirring in a 30 L reaction kettle, 12000 g of sulfolane, 2502.5 g of bisphenol S, 4136.7 g of 4,4'-dibromodiphenyl sulfone, and 1658.5 g of potassium carbonate were added in sequence. After stirring evenly, nitrogen replacement was carried out three times; the amount of water-carrying agent xylene was 4800 g;

[0077] (2) Then, under nitrogen protection, the reaction system was dehydrated at 160 °C for 5 h until no water was produced, and polymerized at 230 °C for 2.5 h;

[0078] (3) After the polymerization reached the end point, 7000 g of sulfolane was added for cooling and dilution. After stirring evenly, 35 g of chloromethane was introduced for end-capping, and the end-capping time was 1 h;

[0079] (4) The salt-containing reaction solution was slowly added to water for precipitation, pulverization, and filtration. The obtained powder was washed 4 times in a mixed solution of sulfolane and cyclohexane (mass ratio 5:14) at 95 °C, and then transferred to pure water for washing 2 times. After centrifugal dehydration, the powder was dried at 150 °C for 12 h to obtain the dried powder.

[0080] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer particles is 0.021%, the 5% thermal weight loss temperature is 535 °C (polyethersulfone), and the coefficient of thermal expansion is 53.7 ppm / °C.

[0081] Example 3

[0082] (1) While stirring in a 30 L reaction kettle, 12000 g of sulfolane, 2283 g of bisphenol A, 2871.5 g of 4,4'-dichlorodiphenyl sulfone, and 1658.5 g of potassium carbonate were added in sequence. After stirring evenly, nitrogen replacement was carried out three times. After stirring evenly, nitrogen replacement was carried out three times; the amount of water-carrying agent xylene was 2400 g;

[0083] (2) Then, under nitrogen protection, the reaction system was dehydrated at 200 °C for 2.5 h until no water was produced, and polymerized at 210 °C for 5 h;

[0084] (3) After the polymerization reached the end point, sulfolane was added for cooling and dilution. After stirring evenly, 35 g of chloromethane was introduced for end-capping, and the end-capping time was 1 h;

[0085] (4) Slowly add the salt-containing reaction solution into water for precipitation, pulverize it, and filter. Wash the obtained powder 4 times in sulfolane and xylene (mass ratio 2:5) at 95 °C, then transfer it to pure water for washing 2 more times, centrifuge to dehydrate to obtain the powder, and dry it at 150 °C for 12 h to obtain the dried powder.

[0086] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer powder is 0.019%, the 5% thermal weight loss temperature is 5257 °C (polysulfone), and the thermal expansion coefficient is 49.3 ppm / °C.

[0087] Example 4

[0088] (1) While stirring in a 30 L reaction kettle, sequentially add 12000 g of sulfolane, 1862 g of 4,4-biphenol, 2929 g of 4,4'-dichlorodiphenyl sulfone, and 1272 g of sodium carbonate. After stirring evenly, conduct nitrogen replacement three times; the amount of the water-carrying agent xylene is 3600 g;

[0089] (2) Then, under nitrogen protection, the reaction system is dehydrated at 170 °C for 3 h until no water is produced, and polymerized at 220 °C for 3.5 h;

[0090] (3) After the polymerization reaches the end point, add 7000 g of sulfolane for cooling and dilution. After stirring evenly, introduce 35 g of chloromethane for end-capping, and the end-capping time is 1 h;

[0091] (4) Slowly add the salt-containing reaction solution into water for precipitation, pulverize it, and filter. Wash the obtained powder 4 times in a mixed solution of sulfolane and toluene (mass ratio 7:14) at 95 °C, then transfer it to pure water for washing 2 more times, centrifuge to dehydrate to obtain the powder, and dry it at 150 °C for 12 h to obtain the dried powder.

[0092] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer powder is 0.023%, the 5% thermal weight loss temperature is 546 °C (polyphenylsulfone), and the thermal expansion coefficient is 57 ppm / °C.

[0093] Comparative Example 1

[0094] (1) While stirring in a 30 L reaction kettle, sequentially add 12000 g of sulfolane, 1862 g of 4,4-biphenol, 2929 g of 4,4'-dichlorodiphenyl sulfone, and 1272 g of sodium carbonate. After stirring evenly, conduct nitrogen replacement three times; the amount of the water-carrying agent xylene is 2400 g;

[0095] (2) Then, under nitrogen protection, the reaction system is dehydrated at 180 °C for 3 h until no water is produced, and polymerized at 220 °C for 3.5 h;

[0096] (3) After the polymerization reaches the end point, 7000 g of sulfolane is added for cooling and dilution. After stirring evenly, 35 g of chloromethane is introduced for end-capping, and the end-capping time is 1 h;

[0097] (4) The salt-containing reaction solution is slowly added to water for precipitation, pulverization, and filtration. The obtained powder is washed 4 times in pure water at 95 °C, centrifuged and dehydrated, and then the powder is dried at 150 °C for 12 h to obtain the dried powder.

[0098] After testing, the content of polybutadiene oligomer impurities in the sulphone polymer powder is 0.091%, the 5% thermal weight loss temperature is 530 °C (polyphenyl sulphone), and the thermal expansion coefficient is 62.3 ppm / °C.

[0099] Comparative Example 2

[0100] (1) In a 30 L reaction kettle under stirring, 12000 g of sulfolane, 2502.5 g of bisphenol S, 4136.7 g of 4,4'-dibromodiphenyl sulfone, and 1658.5 g of potassium carbonate are added in sequence. After stirring evenly, nitrogen replacement is carried out three times. After stirring evenly, nitrogen replacement is carried out three times; the amount of the water-carrying agent xylene is 4800 g;

[0101] (2) Then, under nitrogen protection, the reaction system is dehydrated with water at 160 °C for 5 h until no water is produced, and polymerized at 230 °C for 2.5 h;

[0102] (3) After the polymerization reaches the end point, 7000 g of sulfolane is added for cooling and dilution. After stirring evenly, 35 g of chloromethane is introduced for end-capping, and the end-capping time is 1 h;

[0103] (4) The salt-containing reaction solution is slowly added to water for precipitation, pulverization, and filtration. The obtained powder is washed 4 times in pure water at 95 °C, centrifuged and dehydrated to obtain the powder, and dried at 150 °C for 12 h. The dried powder is extruded and granulated to obtain sulphone polymer particles.

[0104] After testing, the content of polybutadiene oligomer impurities in the sulphone polymer particles is 0.11%, the 5% thermal weight loss temperature is 519 °C (polyethersulfone), and the thermal expansion coefficient is 57.2 ppm / °C.

[0105] Comparative Example 3

[0106] (1) In a 30 L reaction kettle under stirring, 12000 g of sulfolane, 2283 g of bisphenol A, 2871.5 g of 4,4'-dichlorodiphenyl sulfone, and 1658.5 g of potassium carbonate are added in sequence. After stirring evenly, nitrogen replacement is carried out three times. After stirring evenly, nitrogen replacement is carried out three times; the amount of the water-carrying agent xylene is 1200 g;

[0107] (2) Then, under nitrogen protection, the reaction system was dehydrated at 200 °C for 2.5 h until no water was produced, and then polymerized at 210 °C for 5 h;

[0108] (3) After the polymerization reached the end point, 7000 g of sulfolane was added for cooling and dilution. After stirring evenly, 35 g of chloromethane was introduced for end-capping, and the end-capping time was 1 h;

[0109] (4) The salt-containing reaction solution was slowly added to water for precipitation, crushing, and filtration. The obtained powder was washed 4 times in pure water at 95 °C, centrifuged to dehydrate to obtain the powder, and dried at 150 °C for 12 h to obtain the dried powder.

[0110] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer powder was 0.095%, the 5% thermal weight loss temperature was 509 °C (polysulfone), and the thermal expansion coefficient was 57 ppm / °C.

[0111] Comparative Example 4

[0112] (1) Under stirring in a 30 L reaction kettle, 12000 g of sulfolane, 1862 g of 4,4'-biphenol, 2929 g of 4,4'-dichlorodiphenyl sulfone, and 1272 g of sodium carbonate were added in sequence. After stirring evenly, nitrogen replacement was carried out three times; the amount of the water-carrying agent xylene was 3600 g;

[0113] (2) Then, under nitrogen protection, the oil temperature was set at 230 °C for water-carrying and polymerization;

[0114] (3) Then, under nitrogen protection, the reaction system was dehydrated at 170 °C for 3 h until no water was produced, and then polymerized at 220 °C for 3.5 h;

[0115] (4) After the polymerization reached the end point, 7000 g of sulfolane was added for cooling and dilution. After stirring evenly, 35 g of chloromethane was introduced for end-capping, and the end-capping time was 1 h;

[0116] (5) The salt-containing reaction solution was slowly added to water for precipitation, crushing, and filtration. The obtained powder was washed 4 times in pure water at 95 °C, centrifuged to dehydrate to obtain the powder, and dried at 150 °C for 12 h to obtain the dried powder.

[0117] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer particles was 0.12%, the 5% thermal weight loss temperature was 530 °C (polyphenyl sulfone), and the thermal expansion coefficient was 63.4 / °C.

[0118] Comparative Example 5

[0119] 1) Add 12,000 g of N-methylpyrrolidone, 1,862 g of 4,4-biphenol, 2,929 g of 4,4'-dichlorodiphenyl sulfone, and 1,272 g of sodium carbonate into a 30 L reactor in sequence under stirring. After stirring evenly, conduct nitrogen replacement three times;

[0120] (2) Then, under nitrogen protection, set the oil temperature to 200 °C for water removal and polymerization;

[0121] (3) After the polymerization reaches the end point, add 7,000 g of N-methylpyrrolidone for cooling and dilution. After stirring evenly, introduce 35 g of chloromethane for end-capping, and the end-capping time is 1 h;

[0122] (5) Slowly add the salt-containing reaction liquid into water for precipitation, crushing, and filtration. Wash the obtained powder 4 times in pure water at 95 °C, dehydrate by centrifugation to obtain the powder, and dry it at 150 °C for 12 h to obtain the dried powder.

[0123] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer particles is 0, its 5% thermal weight loss temperature is 533 °C (polyphenyl sulfone), and the thermal expansion coefficient is 63.6 ppm / °C.

[0124] Comparative Example 6

[0125] Take 970 g of the salt-containing reaction liquid of Comparative Example 5, add 30 g of polybutadiene oligomer (Qingdao EKS New Materials) to the reaction liquid, stir and mix evenly. Slowly add the reaction liquid mixed with polybutadiene oligomer into water for precipitation, crushing, and filtration. Wash the obtained powder 4 times in pure water at 95 °C, dehydrate by centrifugation to obtain the powder, and dry it at 150 °C for 12 h to obtain the dried powder.

[0126] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer particles is 0.020%, its 5% thermal weight loss temperature is 547 °C (polyphenyl sulfone), and the thermal expansion coefficient is 58 ppm / °C.

[0127] Comparative Example 7

[0128] Take 970 g of the salt-containing reaction liquid of Comparative Example 5, add 120 g of methyl acetate to the reaction liquid, stir evenly. Slowly add the reaction liquid mixed with methyl acetate into water for precipitation, crushing, and filtration. Wash the obtained powder 4 times in pure water at 95 °C, dehydrate by centrifugation to obtain the powder, and dry it at 150 °C for 12 h to obtain the dried powder.

[0129] After testing, the content of polybutadiene oligomer impurities in the sulfone polymer particles is 0%, its 5% thermal weight loss temperature is 532 °C (polyphenyl sulfone), and the thermal expansion coefficient is 63.1 ppm / °C.

[0130] The heat resistance of the sulfone polymers in the above examples and comparative examples is as follows:

[0131]

[0132]

[0133] As can be seen from the above table, the sulfone polymer prepared by the present invention in the sulfolane system contains less than 0.03 wt% of polybutadiene oligomers, making the polymer have better heat resistance, much higher than that of commercially available sulfone polymers.

[0134] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. A sulfone polymer with improved heat resistance, characterized in that, The sulfone polymer is formed by salt-forming polymerization of a bisphenol monomer and 4,4'-dihalodiphenyl sulfone under the condition that sulfolane is used as a solvent. The sulfone polymer contains a polybutadiene oligomer with a mass percentage of m, where 0 < m < 0.03%, preferably 0.01% ≤ m ≤ 0.02%.

2. The sulfone polymer according to claim 1, wherein When the sulfone polymer is polyphenyl sulfone, its 5% thermal weight loss temperature is greater than 540 °C, and its coefficient of thermal expansion is less than 62.4 ppm / °C; and / or When the sulfone polymer is polyethersulfone, its 5% thermal weight loss temperature is greater than 525 °C, and its coefficient of thermal expansion is less than 55 ppm / °C; and / or When the sulfone polymer is polysulfone, its 5% thermal weight loss temperature is greater than 510 °C, and its coefficient of thermal expansion is less than 55 ppm / °C.

3. The method for preparing a sulfone polymer with improved heat resistance according to claim 1 or 2, characterized in that, It includes the following steps: 1) Add the bisphenol monomer, 4,4'-dihalodiphenyl sulfone, and salt-forming agent in proportion to the sulfolane solvent and water-carrying agent, and mix evenly; 2) Raise the temperature to 160 - 200 °C under nitrogen protection to separate water, and then polymerize at 210 - 230 °C; 3) After the polymerization reaches the end point, mix the cold solvent with the high-temperature reaction solution. When the reaction solution cools to 130 - 150 °C, add a capping agent for capping, and the capping time is 0.5 - 1 h; 4) Precipitate and crush the capped reaction solution in water, then wash the obtained powder with a compound solvent and pure water, and dry and granulate to obtain sulfone polymer particles.

4. The preparation method according to claim 3, wherein In step 1), the 4,4'-dihalodiphenyl sulfone is selected from one or more of 4,4'-dichlorodiphenyl sulfone, 4,4'-dibromodiphenyl sulfone, and 4,4'-difluorodiphenyl sulfone, preferably 4,4'-dichlorodiphenyl sulfone; and / or The bisphenol monomer is selected from one or more of bisphenol A, bisphenol S, and biphenol; and / or The salt-forming agent is selected from one or several of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, preferably potassium carbonate or sodium carbonate.

5. The preparation method according to claim 3 or 4, characterized in that, In step 1), the molar ratio of the bisphenol monomer, 4,4'-dihalodiphenyl sulfone, and salt-forming agent is 1:0.97 - 1.03:1.05 - 2.

6.

6. The preparation method according to claim 3 or 4, characterized in that, In step 1), the water-carrying agent is selected from at least one of benzene, xylene, chlorobenzene, and mesitylene, preferably xylene; Preferably, the dosage of the water-carrying agent is 10 wt% - 40 wt% of the mass of the sulfolane solvent, preferably 20 wt% - 30 wt%.

7. The preparation method according to claim 3, wherein In step 3), the capping agent is a haloalkane, preferably selected from one or several of chloromethane, chloroethane, bromomethane, and bromoethane, more preferably chloromethane; Preferably, the dosage of the capping agent is 0.02 - 0.08 moles of the capping agent per mole of monomer.

8. The preparation method according to claim 3, wherein, In step 4), the compound solvent is sulfolane and one or more of benzene, xylene, toluene, cyclohexane, and n-hexane, preferably sulfolane and toluene, n-hexane; Preferably, based on the mass of the compound solvent being 100%, the mass proportion of sulfolane is 10 - 40%, preferably 20% - 30%; the mass proportion of one or more of benzene, toluene, xylene, cyclohexane, and n-hexane is 60 - 90%, preferably 70% - 80%.

9. The preparation method according to claim 3 or 8, characterized in that, In step 4), the obtained powder is washed 1 to 5 times, preferably 4 times, in the compound solvent, and washed 1 to 2 times, preferably 2 times, with pure water.

10. Use of the heat-resistant sulfone polymer according to any one of claims 1 to 2 or the heat-resistant sulfone polymer prepared by the preparation method according to any one of claims 3 to 9 in the production of molded articles, fibers, films, membranes.

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