Sulfone polymer as well as preparation method and application thereof

Abstract

The invention discloses a sulfone polymer as well as a preparation method and application thereof, and belongs to the technical field of polymers. The preparation method of the sulfone polymer provided by the invention comprises the following steps: mixing raw materials for synthesizing the sulfone polymer, then carrying out polymerization reaction, adding supercritical carbon dioxide into a reaction solution until the reaction solution reaches target viscosity, carrying out first heat preservation and pressure preservation, and then adding water, and carrying out second heat preservation and pressure preservation; and after the second heat and pressure preservation is finished, reducing pressure and temperature, washing and drying to obtain the sulfone polymer. The sulfone polymer obtained by adopting the technical scheme has the advantages of excellent purity, low yellowness index and larger specific surface area. Meanwhile, the preparation method of the sulfone polymer provided by the invention is simple to operate and beneficial to actual production.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis, and in particular relates to a sulfone polymer and a preparation method and application thereof. Background Art

[0002] Sulfone polymers are synthesized by solution polymerization and then undergo precipitation, crushing, purification, drying, and extrusion to produce pure sulfone polymer resin particles. The polymer solution is precipitated in a precipitation bath containing water or a mixture of water and a solvent, then crushed into a powder. In the next purification step, the reaction solvent and by-product salts, among other impurities, are extracted from the resin using water or another solvent. The impurity-free resin powder is then vacuum-dried to obtain sulfone polymer resin powder, which is then extruded to produce resin particles. During the precipitation process, the polymer solution contacts the precipitation bath, forming a dense film on the surface of the precipitated resin. The resin also has a dense structure with few pores and small pores. In the next purification step, when sulfolane and by-product salts are extracted from the resin using water or another solvent, the slow diffusion rate of these impurities within the resin results in high residual levels of the reaction solvent, oligomers, and by-product salts, resulting in a dark resin color. Furthermore, the resulting sulfone polymer has a small specific surface area, limiting its application range.

[0003] Prior art methods for preparing low-color resins include, for example, patent CN 118221939A. After the reaction is complete, a capping agent is added, the capped polyphenylsulfone resin polymer solution is cooled, citric acid is added, and then a metal ion catalyst and an oxidant are added to react to obtain a low-color polyphenylsulfone resin polymer solution. The low-color polyphenylsulfone resin polymer solution is then post-treated to obtain a polyphenylsulfone resin. This method, however, involves numerous additives, a complex post-processing process, and difficulty controlling residual impurities. For example, patent CN 112552528B introduces a cracking product of the solvent sorbitol and utilizes a supercritical fluid to remove the aprotic polar solvent from the polymerization reaction, thereby reducing the number of resin washes. However, after extraction and separation, this method releases CO2, leaving a mixture of the introduced solvent and the aprotic polar solvent. To recover the aprotic polar solvent, the two components must be distilled and separated, and the sorbitol cracking product cannot be reused. In addition, the prior art also uses supercritical carbon dioxide to prepare microporous sulfone polymers. However, in the prior art, the resin is solidified and then a series of treatments are performed before supercritical carbon dioxide is introduced for preparation. This method is not only cumbersome to operate, but also the resulting sulfone polymer has low purity, dark color, and a small specific surface area.

[0004] Therefore, how to provide a sulfone polymer that can prepare low-color resin while ensuring purity and specific surface area has become a research hotspot. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a sulfone polymer having low reaction solvent residue, low yellowness index and high specific surface area, as well as a preparation method and application thereof.

[0006] To achieve the above object, in a first aspect of the present invention, the present invention provides a method for preparing a sulfone polymer, the preparation method comprising the following steps:

[0007] The raw materials for synthesizing a sulfone polymer are mixed and subjected to polymerization reaction. After the reaction liquid reaches a target viscosity, supercritical carbon dioxide is added to the reaction liquid for a first heat preservation and pressure maintenance, and then water is added for a second heat preservation and pressure maintenance. After the second heat preservation and pressure maintenance, the pressure and temperature are reduced, the reaction liquid is washed, and the reaction liquid is dried to obtain a sulfone polymer.

[0008] The first heat preservation and pressure holding time is 0.2-2h;

[0009] The second heat preservation and pressure holding time is 0.2-4h;

[0010] During the temperature reduction and pressure reduction, the pressure change rate is ≥1.5MPa / min, and the temperature change rate is ≥45°C / min; the pressure of the system is reduced to ≤-0.098MPa, and the temperature is reduced to <100°C.

[0011] The present invention adds supercritical carbon dioxide to a reaction liquid that has reacted to a target viscosity, performs a first heat preservation and pressure preservation, and the added supercritical carbon dioxide can fully permeate with the reaction liquid and swell to a molecular diffusion equilibrium during the first heat preservation and pressure preservation time; then adds water to perform a second heat preservation and pressure preservation, and hydrogen bonds and hydroxyl radicals contained in the water can further promote the combination of the supercritical carbon dioxide and the reaction solvent remaining in the reaction liquid, thereby improving the swelling effect of the supercritical carbon dioxide and dissolving part of the by-product salt; then reduces the pressure and temperature to a specific pressure and temperature range at a specific temperature and pressure reduction rate, and effectively removes the reaction solvent and part of the by-product salt substances in the reaction liquid under the dual effects of gasification of the supercritical carbon dioxide and gasification of the solvent. The surface of the prepared resin powder presents a porous structure, and impurities such as oligomers and by-product salt substances can be further removed in conjunction with a subsequent washing process, thereby reducing the residual reaction solvent and by-product substances in the sulfone polymer, reducing the resin chromaticity, and increasing the specific surface area.

[0012] Illustratively, the first heat preservation and pressure holding time may be any point value or any two point range values ​​between 0.2-2h, for example, 0.2h, 0.4h, 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc. The second heat preservation and pressure holding time may be any point value or any two point range values ​​between 0.2-4h, for example, 0.2h, 0.4h, 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, etc.

[0013] For example, after the pressure reduction and temperature reduction, the pressure of the system can be any point value or any two point range value ≤-0.098MPa, such as (-0.1)-(-0.0995)MPa, (-0.0995)-(-0.0990)MPa, (-0.0990)-(-0.0985)MPa, (-0.0985)-(-0.0980)MPa, etc., or can be -0.1MPa, -0.0995MPa, -0.0990MPa, -0.0985MPa, -0.0980MPa, etc.; the temperature can be any point value or any two-point range value <100℃, for example, it can be 20-90℃, 20-80℃, 30-50℃, 40-70℃, 20-40℃, etc., or it can be 99℃, 90℃, 80℃, 70℃, 60℃, 50℃, 40℃, 30℃, 20℃, etc.

[0014] Exemplarily, during the cooling and pressure reduction, the rate of change of pressure may be any point value or any two-point range value between ≥1.5 MPa / min, for example, 1.5-25 MPa / min, or 1.5 MPa / min, 3 MPa / min, 5 MPa / min, 7 MPa / min, 9 MPa / min, 11 MPa / min, 13 MPa / min, 15 MPa / min, 17 MPa / min, 19 MPa / min, 21 MPa / min, 23 MPa / min, 25 MPa / min, etc.; the rate of change of temperature may be any point value or any two-point range value between ≥45°C / min, for example, 45-95°C / min, or 45°C / min, 50°C / min, 55°C / min, 60°C / min, 65°C / min, 70°C / min, 75°C / min, 80°C / min, 85°C / min, 90°C / min, 95°C / min, etc.

[0015] As a preferred embodiment of the preparation method of the present invention, the first heat preservation and pressure preservation time is 0.5-1h.

[0016] As a preferred embodiment of the preparation method of the present invention, the second heat preservation and pressure preservation time is 0.5-2h.

[0017] The present invention has found that the time for the first heat preservation and pressure holding and the second heat preservation and pressure holding has a significant effect on the color, purity, etc. of the sulfone polymer. When the time for the first heat preservation and pressure holding and the second heat preservation and pressure holding is further selected to be within the above range, while ensuring that the residual reaction solvent is fully swollen and part of the by-product salt is dissolved, other impurities will not be introduced, thereby effectively reducing the reaction solvent, oligomer residues and by-product salt residues in the prepared sulfone polymer, and ensuring the color of the prepared sulfone polymer.

[0018] As a preferred embodiment of the preparation method of the present invention, during the cooling and pressure reduction, the pressure change rate is 16-20 MPa / min, and the temperature change rate is 70-80°C / min.

[0019] The present invention has found that when the rate of change of pressure and temperature during the temperature reduction and pressure reduction is further selected to be within the above range, the comprehensive effect of the obtained sulfone polymer is more excellent.

[0020] As a preferred embodiment of the preparation method of the present invention, the temperature of the first heat preservation and pressure preservation is 160-240° C., and the pressure is 10-25 MPa.

[0021] As a preferred embodiment of the preparation method of the present invention, the temperature of the second heat preservation and pressure preservation is 160-240° C., and the pressure is 10-25 MPa.

[0022] Exemplarily, the temperatures of the first thermal insulation and pressure holding and the second thermal insulation and pressure holding can each independently be any point value or any two point range values ​​between 160-240°C, for example, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, etc.; the pressures can each independently be any point value or any two point range values ​​between 10-25MPa, for example, 10MPa, 12MPa, 14MPa, 16MPa, 18MPa, 20MPa, 22MPa, 24MPa, 25MPa, etc.

[0023] Preferably, the temperature of the first heat preservation and pressure preservation is 180-205° C., and the pressure is 16-20 MPa.

[0024] Preferably, the temperature of the second heat preservation and pressure preservation is 180-205° C., and the pressure is 16-20 MPa.

[0025] The present invention has found that when the temperature and pressure of the first heat preservation and pressure maintenance and the second heat preservation and pressure maintenance are further selected to be within the above ranges, the comprehensive performance of the obtained sulfone polymer is better.

[0026] As a preferred embodiment of the preparation method of the present invention, the temperature of the supercritical carbon dioxide is 40-80° C. and the pressure is 10-30 MPa.

[0027] Exemplarily, the temperature of the supercritical carbon dioxide can be any point value or any two point range values ​​between 40-80°C, such as 40°C, 50°C, 60°C, 70°C, 80°C, etc.; the pressure can be any point value or any two point range values ​​between 10-30MPa, such as 10MPa, 12MPa, 14MPa, 16MPa, 18MPa, 20MPa, 22MPa, 24MPa, 26MPa, 28MPa, 30MPa, etc.

[0028] Preferably, the temperature of the supercritical carbon dioxide is 50-60° C. and the pressure is 16-20 MPa.

[0029] As a preferred embodiment of the preparation method of the present invention, the mass percentage of water added during the second heat and pressure maintenance step is 0.001-0.03% based on the reaction liquid.

[0030] Exemplarily, based on the reaction liquid, the mass percentage of water added during the second heat and pressure maintenance process can be any point value between 0.001-0.03% or any two point range values, such as 0.001%, 0.005%, 0.01%, 0.012%, 0.014%, 0.016%, 0.018%, 0.020%, 0.022%, 0.024%, 0.026%, 0.028%, 0.030%, etc.

[0031] Preferably, based on the reaction liquid, the mass percentage of water added during the second heat and pressure maintenance step is 0.016-0.022%.

[0032] The present invention has found that the amount of water added during the second heat preservation and pressure holding not only affects the residual reaction solvent, oligomers and by-product salt substances in the sulfone polymer, thereby affecting the colorimetry of the prepared sulfone polymer, but also has a certain influence on the specific surface area of ​​the sulfone polymer. When the mass percentage of water added during the second heat preservation and pressure holding, calculated on the reaction liquid, is further selected to be within the above range, the comprehensive performance of the obtained sulfone polymer is better.

[0033] The preparation method provided herein is suitable for the preparation of all sulfone polymers, such as bisphenol A polysulfone, polyethersulfone, and polyphenylsulfone. The viscosity of the polymerization reaction is measured based on the properties of the target sulfone polymer. When the viscosity reaches the target sulfone polymer viscosity of 100-3000 cps, the subsequent steps of the present invention are performed.

[0034] The present invention uses conventional phenolic monomers and sulfone monomers; at the same time, the polymerization reaction solvent used is also a conventional solvent. For example, depending on the target sulfone polymer, the polymerization reaction solvent can be at least one of dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and diphenyl sulfone.

[0035] Preferably, when the sulfone polymer is bisphenol A type polysulfone, the polymerization reaction solvent is sulfolane, N,N-dimethylacetamide or dimethyl sulfoxide; when the sulfone polymer is polyethersulfone, the polymerization reaction solvent is sulfolane, N,N-dimethylformamide or diphenyl sulfone; when the sulfone polymer is polyphenylsulfone, the polymerization reaction solvent is sulfolane or N,N-dimethylformamide.

[0036] As a preferred embodiment of the preparation method of the present invention, the washing is performed with water.

[0037] The drying is carried out under vacuum conditions at a temperature of 55-65° C. for 4-6 hours.

[0038] In a second aspect of the present invention, the present invention provides a sulfone polymer, which is prepared by the preparation method of the present invention.

[0039] As a preferred embodiment of the sulfone polymer of the present invention, the specific surface area of ​​the sulfone polymer is ≥151m 2 / g, YI value ≤11.27, reaction solvent residue ≤363ppm.

[0040] In a third aspect of the present invention, the present invention provides use of the sulfone polymer in preparing food containers.

[0041] As a preferred embodiment of the application of the present invention, the food container includes at least one of a water cup and a lunch box.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The invention adds supercritical carbon dioxide to a reaction liquid that has reacted to a target viscosity, performs a first heat preservation and pressure preservation, and the added supercritical carbon dioxide can fully permeate with the reaction liquid and swell to a molecular diffusion equilibrium during the first heat preservation and pressure preservation time; then adds water to perform a second heat preservation and pressure preservation, and hydrogen bonds and hydroxyl radicals contained in the water can further promote the combination of the supercritical carbon dioxide and the reaction solvent remaining in the reaction liquid, thereby improving the swelling effect of the supercritical carbon dioxide and dissolving part of the by-product salt; then reduces the pressure and temperature to a specific pressure and temperature range at a specific pressure reduction and temperature reduction rate, and then washes; under the dual effects of supercritical carbon dioxide gasification and solvent gasification, combined with subsequent washing, the reaction solvent, oligomers and by-product salt substances remaining in the reaction liquid can be effectively removed, thereby reducing the yellowness index of the sulfone polymer and increasing the specific surface area. DETAILED DESCRIPTION

[0044] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0045] Unless otherwise specified, the reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in the art; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch of raw materials.

[0046] Example 1

[0047] An embodiment of the present invention provides a sulfone polymer, specifically polyphenylene sulfone, and a method for preparing the sulfone polymer comprises the following steps:

[0048] In a nitrogen-protected 100-L reactor, 36 kg of sulfolane, 8.79 kg of 4,4'-dichlorodiphenyl sulfone, and 5.59 kg of 4,4'-biphenyldiphenol were quantitatively added. After stirring and heating to 60°C, 3.3 kg of sodium carbonate and 3 kg of xylene were added. The temperature was stirred and raised to 200°C and maintained for 5 hours. The reaction system was then heated to 235°C and maintained for 3 hours until the reaction solution reached the target viscosity of 680 cps.

[0049] Supercritical CO2 at a pressure of 16 MPa and a temperature of 60°C was introduced into the reactor for the first insulation and pressure maintenance (temperature 205°C, pressure 16 MPa, time 0.5 h), 125 g of water (the mass percentage of water based on the reaction liquid was 0.016%) was added to the reactor for the second insulation and pressure maintenance (temperature 205°C, pressure 16 MPa, time 0.5 h), and then the solution after the second insulation and pressure maintenance was cooled and reduced in pressure (pressure drop rate of 16 MPa / min, temperature drop rate of 80°C / min) to a pressure of -0.1 MPa, and then cooled to a temperature of 95°C; then water was added for washing, and the washed solution was placed in a vacuum dryer and dried at 60°C for 5 h to obtain a sulfone polymer.

[0050] Examples 2-14 and Comparative Examples 1-8

[0051] Examples 2-14 of the present invention and comparative examples 1-8 explored the effects of the first and second heat preservation and pressure maintenance parameters, the cooling and pressure reduction parameters, the supercritical carbon dioxide parameters, and the amount of water added. Except for the parameters in Table 1, the rest were consistent with those in Example 1; wherein the amount of water added was based on the mass of the reaction liquid; at the same time, the parameters of Example 1 are listed in Table 1;

[0052] Table 1

[0053]

[0054] Example 15

[0055] An embodiment of the present invention provides a sulfone polymer, specifically polyethersulfone, and a method for preparing the sulfone polymer comprises the following steps:

[0056] In a nitrogen-protected 100-L reactor, 37 kg of sulfolane, 8.79 kg of 4,4'-dichlorodiphenyl sulfone, and 7.56 kg of 4,4'-dihydroxydiphenyl sulfone were quantitatively added. After stirring and heating to 60°C, 3.3 kg of sodium carbonate and 3 kg of xylene were added. The temperature was then maintained at 200°C for 5 hours. The reaction system was then heated to 235°C and maintained for 3 hours until the reaction solution reached the target viscosity of 572 cps.

[0057] Supercritical CO2 at a pressure of 16 MPa and a temperature of 60°C is introduced into a reactor containing the reaction liquid, and a first heat and pressure maintenance period is carried out (temperature 205°C, pressure 16 MPa, time 0.5 h). 125 g of water (the mass percentage of water based on the reaction liquid is 0.016%) is added to the reactor and a second heat and pressure maintenance period is carried out (temperature 205°C, pressure 16 MPa, time 0.5 h). Subsequently, the solution after the second heat and pressure maintenance period is cooled and reduced in temperature (pressure drop rate of 16 MPa / min, temperature drop rate of 80°C / min) to a pressure of -0.1 MPa and a temperature of 95°C; then, water is added for washing, and the washed solution is placed in a vacuum dryer and dried at 60°C for 5 h to obtain a sulfone polymer.

[0058] Example 16

[0059] An embodiment of the present invention provides a sulfone polymer, specifically polysulfone, and a method for preparing the sulfone polymer comprises the following steps:

[0060] In a nitrogen-protected 100-L reactor, 37 kg of sulfolane, 9.87 kg of 4,4'-dichlorodiphenyl sulfone, and 7.42 kg of 2,2-bis(4-hydroxyphenyl)propane were quantitatively added. The mixture was stirred and heated to 60°C. 4.61 kg of potassium carbonate and 3 kg of xylene were then added. The temperature was then maintained at 200°C for 5 hours. The reaction system was then heated to 235°C and maintained for 3 hours until the reaction solution reached the target viscosity of 724 cps.

[0061] Supercritical CO2 at a pressure of 16 MPa and a temperature of 60°C is introduced into the reactor, and the first heat and pressure maintenance is carried out (temperature 205°C, pressure 16 MPa, time 0.5 h), 125 g of water (the mass percentage of water based on the reaction liquid is 0.016%) is added to the reactor, and the second heat and pressure maintenance is carried out (temperature 205°C, pressure 16 MPa, time 0.5 h), and then the solution after the second heat and pressure maintenance is cooled and reduced in temperature (pressure drop rate of 16 MPa / min, temperature drop rate of 80°C / min) to a pressure of -0.1 MPa and a temperature of 95°C; then water is added for washing, and the washed solution is placed in a vacuum dryer and dried at 60°C for 5 h to obtain a sulfone polymer.

[0062] Comparative Example 9

[0063] The comparative example of the present invention provides a sulfone polymer, specifically polyphenylene sulfone, and the preparation method of the sulfone polymer comprises the following steps:

[0064] In a nitrogen-protected 100-L reactor, 36 kg of sulfolane, 8.79 kg of 4,4'-dichlorodiphenyl sulfone, and 5.59 kg of 4,4'-biphenyldiphenol were quantitatively added. After stirring and heating to 60°C, 3.3 kg of sodium carbonate and 3 kg of xylene were added. The temperature was then maintained at 200°C for 5 hours. The reaction system was then heated to 235°C and maintained for 3 hours until the reaction solution reached the target viscosity of 680 cps.

[0065] Supercritical CO2 at a pressure of 16 MPa and a temperature of 60°C was introduced into the reactor, and the first heat and pressure maintenance was carried out (temperature 205°C, pressure 16 MPa, time 1h). Subsequently, the solution after the first heat and pressure maintenance was cooled and reduced in temperature and pressure (pressure drop rate of 16 MPa / min, temperature drop rate of 80°C / min) to a pressure of -0.1 MPa and a temperature of 95°C; then water was added for washing, and after washing, the solution was placed in a vacuum dryer and dried at 60°C for 5h to obtain a sulfone polymer.

[0066] Comparative Example 10

[0067] The comparative example of the present invention provides a sulfone polymer, specifically polyphenylene sulfone, and the preparation method of the sulfone polymer comprises the following steps:

[0068] In a nitrogen-protected 100-L reactor, 36 kg of sulfolane, 8.79 kg of 4,4'-dichlorodiphenyl sulfone, and 5.59 kg of 4,4'-biphenyldiphenol were quantitatively added. After stirring and heating to 60°C, 3.3 kg of sodium carbonate and 3 kg of xylene were added. The temperature was then maintained at 200°C for 5 hours. The reaction system was then heated to 235°C and maintained for 3 hours until the reaction solution reached the target viscosity of 680 cps.

[0069] 125 g of water (the mass percentage of water based on the reaction liquid is 0.016%) was added to the reactor for a second heat and pressure maintenance period (temperature 205°C, pressure 16 MPa, time 1 h). After the second heat and pressure maintenance period, the solution was cooled and pressure-reduced (pressure drop rate of 16 MPa / min, temperature drop rate of 80°C / min) to a pressure of -0.1 MPa and a temperature of 95°C; then, water was added for washing, and after washing, the solution was placed in a vacuum dryer and dried at 60°C for 5 h to obtain a sulfone polymer.

[0070] Effect Examples

[0071] The effects of the present invention are investigated in detail by investigating the properties of the sulfone polymers prepared in Examples 1-16 and Comparative Examples 1-10, including the following:

[0072] 1. Reaction solvent residue: Use deuterated chloroform to prepare a solution, and test it by nuclear magnetic resonance spectroscopy (1HNMR). The sulfolane content in the resin is calculated based on the peak area ratio at δ = 7.58 and δ = 3.05 in the spectrum;

[0073] 2. Specific surface area: tested with a specific surface and pore size analyzer. The test method refers to GB / T 19587-2017 "Determination of the specific surface area of ​​solid substances by gas adsorption BET method";

[0074] 3. Yellowness Index Test: Sulfone polymer was extruded through a twin-screw extruder to obtain resin pellets, which were injection molded at 360°C to obtain a standard color plate with a thickness of 2 mm. The YI value was determined using a colorimeter according to ASTM D1925.

[0075] The results are shown in Table 2;

[0076] Table 2

[0077]

[0078] As can be seen from Table 2, the sulfone polymer prepared by the technical solution provided by the present invention has a low yellowness index, low reaction solvent residue, and a high specific surface area; specifically, the reaction solvent residue of the obtained sulfone polymer is below 363 ppm, and the specific surface area is 151 m 2 / g or above, and the YI value is below 11.27;

[0079] It can be seen from Examples 1-8 that the parameters of the first heat-insulating and pressure-holding treatment and the second heat-insulating and pressure-holding treatment will affect the properties of the obtained sulfone polymer. When the parameters of the first heat-insulating and pressure-holding treatment and the second heat-insulating and pressure-holding treatment are selected within the preferred range of the present invention, the overall effect of the obtained sulfone polymer is better. It can be seen from Example 1 and Comparative Examples 1-4 that when the parameters of the first heat-insulating and pressure-holding treatment and the second heat-insulating and pressure-holding treatment are not within the range given by the present invention, the residual reaction solvent of the obtained sulfone polymer increases significantly and the YI value is significantly improved.

[0080] As can be seen from Example 1 and Examples 9-12, the parameters of supercritical carbon dioxide and the amount of water added will also affect the properties of the sulfone polymer; as can be seen from Example 1 and Comparative Example 9, when only supercritical carbon dioxide is used without adding water, the residual reaction solvent of the obtained sulfone polymer increases significantly, and the color of the obtained sulfone polymer is also darker; as can be seen from Example 1 and Comparative Example 10, when only water is added without introducing supercritical carbon dioxide, the residual reaction solvent of the obtained sulfone polymer increases sharply, the specific surface area decreases sharply, and the color of the obtained sulfone polymer is also significantly darker.

[0081] It can be seen from Example 1, Examples 13-14 and Comparative Examples 5-8 that the cooling rate, the pressure reduction rate, and the temperature and pressure after cooling and pressure reduction in the cooling and pressure reduction treatment all affect the properties of the sulfone polymer. When the pressure reduction rate in Comparative Example 5 is too low, the specific surface area of ​​the obtained sulfone polymer decreases significantly, and the residual reaction solvent shows an increasing trend; when the cooling rate in Comparative Example 6 is too slow, the color of the obtained sulfone polymer tends to deepen, and the specific surface area of ​​the obtained sulfone polymer also shows a certain downward trend; when the temperature or pressure after cooling and pressure reduction in Comparative Examples 7-8 is too high, the specific surface area of ​​the obtained sulfone polymer decreases significantly, the residual reaction solvent shows a significant increasing trend, and the color of the obtained sulfone polymer deepens.

[0082] Finally, it should be noted that the above embodiments are intended to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a sulfone polymer, characterized in that: The preparation method comprises the following steps: The raw materials for synthesizing sulfone polymer are mixed and subjected to polymerization reaction, and after reaching the target viscosity, supercritical carbon dioxide is added to the reaction solution for the first heat preservation and pressure maintenance, and then water is added for the second heat preservation and pressure maintenance; after the second heat preservation and pressure maintenance is completed, the pressure and temperature are reduced, the solution is washed, and the solution is dried to obtain the sulfone polymer; The first heat preservation and pressure holding time is 0.2-2h; The second heat preservation and pressure holding time is 0.2-4h; During the temperature reduction and pressure reduction, the pressure change rate is ≥1.5MPa / min, and the temperature change rate is ≥45°C / min; the pressure of the system is reduced to ≤-0.098MPa, and the temperature is reduced to <100°C.

2. The preparation method according to claim 1, characterized in that: The first heat preservation and pressure holding time is 0.5-1h; And / or, the second heat preservation and pressure preservation time is 0.5-2h.

3. The preparation method according to claim 1, characterized in that: During the temperature and pressure reduction, the pressure change rate is 16-20 MPa / min, and the temperature change rate is 70-80°C / min.

4. The preparation method according to claim 1, characterized in that: The temperature of the first heat preservation and pressure preservation is 160-240° C. and the pressure is 10-25 MPa; And / or, the temperature of the second heat-insulating and pressure-insulating process is 160-240° C., and the pressure is 10-25 MPa.

5. The preparation method according to claim 1, characterized in that: The temperature of the supercritical carbon dioxide is 40-80° C., and the pressure is 10-30 MPa.

6. The preparation method according to claim 1, characterized in that: Calculated on the reaction liquid, the mass percentage of water added in the second heat preservation and pressure maintenance is 0.001-0.03%.

7. A sulfone polymer, characterized in that The sulfone polymer is prepared by the preparation method according to any one of claims 1 to 6.

8. The sulfone polymer according to claim 7, characterized in that The specific surface area of ​​the sulfone polymer is ≥151m 2 / g, YI value ≤11.27, reaction solvent residue ≤363ppm.

9. Use of the sulfone polymer according to claim 7 or 8 in the preparation of food containers.

10. The use according to claim 9, characterized in that The food container includes at least one of a water cup and a lunch box.

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