Sulfone resin micropowder as well as preparation method and application thereof

Abstract

The invention discloses sulfone resin micro powder as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. According to the preparation method of the sulfone resin micropowder provided by the invention, the good solvent is added into the reaction system after the polymerization reaction is finished, so that the solubility of the sulfone resin obtained by polymerization can be effectively improved; meanwhile, the dispersing agent is added after the good solvent is added, so that the dispersing effect of the sulfone resin obtained through polymerization can be more effectively improved; therefore, when supercritical carbon dioxide in a certain pressure range is subsequently introduced and then added into water at a specific flow rate for precipitation, the sulfone resin obtained by polymerization can be dispersed into finer and more uniform liquid drops, the solidification time of the sulfone resin in water is shortened, the introduction of impurities is reduced, and the purity of the sulfone resin is improved.

Description

Technical Field

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

[0002] The current method for preparing sulfone resin powder coatings is to perform secondary processing on the resin powder obtained in the primary form of synthesis to prepare fine-particle micro-powder slurry. The processing method is to mix the resin powder, solvent and water into a slurry in a certain proportion and then put it into a ball mill for long-term wet grinding. This method has the problems of long grinding time and wide and uneven distribution of the obtained powder particle size. In addition, the molecular structure of the sulfone resin is mechanically destroyed during the ball milling process, and it is easy to yellow when used.

[0003] In view of the above problems, many solutions have been proposed in the prior art. Chinese patents with application numbers CN201410136633.5 and CN200510016654.4 disclose a method for preparing redispersible polyethersulfone micropowders: first, polyethersulfone resin is dissolved in a mixed solution of an organic solvent and a cosolvent to form a solution, and then the solvent is slowly added to a surfactant aqueous solution for high-speed dispersion to obtain an emulsion, and the emulsion is diluted with deionized water and added to an extractant, and then centrifuged or filtered to obtain polyethersulfone micropowders; or the emulsion is evaporated, the organic solvent is removed, and then dried to prepare micropowders. The preparation methods disclosed in the above two patents have the following disadvantages: the surfactant used has residues in the resin, which will decompose when used at high temperatures, resulting in obvious yellowing of the product; at the same time, the surfactant remains in the wastewater during the purification process, which is difficult to recycle and easily causes environmental pollution. The Chinese patent with application number CN201910054395.6 discloses a micro-powder prepared by solidification separation and drying after constructing a slightly turbid dispersion system of polyethersulfone, mixed solvent and water; the main disadvantage of this preparation method is that deionized water is used for washing in the purification process, and the amount of water used is 20-40 times the weight of the resin, that is, the amount of water used is large and the cost of wastewater treatment is high. The Chinese patent with application number CN201711188865.5 discloses an industrial synthesis method of coating-grade ultrafine polyarylethersulfone resin, in which aromatic dihydric phenol is added to the system during the polymerization reaction, and then a certain proportion of a mixture of deionized water and cyclopentane is added to dilute the polymerized mucus, crushed, purified, and dried to obtain pure coating-grade polyarylethersulfone resin ultrafine powder. The disadvantage of this preparation method is that the dihydric phenol added during the polymerization reaction reacts with the raw material dichloride to generate long-chain by-products, which affects the purity of the product. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a sulfone resin micropowder with low oligomer content, small D50 particle size and uniform particle size distribution, as well as a preparation method and application thereof.

[0005] To achieve the above object, in a first aspect of the present invention, the present invention provides a method for preparing sulfone resin micropowder, the preparation method comprising the following steps:

[0006] (1) adding a sulfone resin reaction monomer, an azeotropic agent, and a salt-forming agent to a reaction solvent under an inert gas environment to carry out a salt-forming reaction and a polymerization reaction;

[0007] (2) cooling the reaction system after the polymerization reaction is completed, and sequentially adding a good solvent and a dispersant to the reaction system after the reaction is cooled and stirring to obtain a mixed solution;

[0008] (3) introducing supercritical carbon dioxide at a pressure of ≥8 MPa into the mixed solution and maintaining the pressure, and after the maintenance, adding the mixed solution to water at a flow rate of 10-300 L / min, followed by boiling, solid-liquid separation, collecting the filter residue and drying it to obtain a sulfone resin;

[0009] The good solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide;

[0010] The dispersant includes at least one of chloroform, ethylene dichloride, ethanol, 1,3-propylene glycol, ethyl acetate, and butyl acetate.

[0011] In the preparation method of sulfone resin micropowder provided by the present invention, the temperature is lowered after the polymerization reaction is completed, and a good solvent is added to the reaction system after the temperature is lowered, so that the solubility of the sulfone resin obtained by polymerization can be effectively improved; at the same time, a dispersant is added after the good solvent is added, so that the dispersion effect of the sulfone resin obtained by polymerization can be more effectively improved; so that when supercritical carbon dioxide within a certain pressure range is subsequently introduced and added to water at a specific flow rate for precipitation, the sulfone resin obtained by polymerization can be dispersed into finer and more uniform droplets, shortening the solidification time of the sulfone resin in water, reducing the introduction of impurities, and reducing the content of oligomers in the resin.

[0012] Exemplarily, the pressure of the supercritical carbon dioxide may be any point value or any two point range values ​​between ≥8 MPa, for example, 10-30 MPa, 15-20 MPa, or 8 MPa, 10 MPa, 12 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa, 22 MPa, 24 MPa, 26 MPa, 28 MPa, 30 MPa, etc.

[0013] Preferably, the pressure of the supercritical carbon dioxide is 10-30 MPa.

[0014] More preferably, the pressure of the supercritical carbon dioxide is 15-20 MPa.

[0015] The present invention has found that effective mutual swelling and diffusion can occur between supercritical carbon dioxide and sulfone resin, so that when flowing into water at a certain rate later, it is more conducive to the dispersion of sulfone resin into a product with a smaller D50 particle size and a more uniform particle size distribution; especially when the pressure of supercritical carbon dioxide is further selected to be 15-20MPa, the comprehensive performance of the obtained sulfone resin is better. If the pressure of supercritical carbon dioxide is too low, the swelling effect is not obvious, which is not conducive to subsequent dispersion; if the pressure of supercritical carbon dioxide is too high, the manufacturing requirements for equipment are increased, and the requirements for the stability of pressure release process control are also increased when it is added to water at a certain flow rate later.

[0016] Exemplarily, the flow rate can be any point value or any two point range value between 10-300 L / min, such as 12-290 L / min, 150-200 L / min, or can be 10 L / min, 10 L / min, 30 L / min, 50 L / min, 70 L / min, 90 L / min, 100 L / min, 120 L / min, 140 L / min, 160 L / min, 180 L / min, 200 L / min, 220 L / min, 240 L / min, 260 L / min, 280 L / min, 300 L / min, etc.

[0017] Preferably, supercritical carbon dioxide at a pressure of 10-30 MPa is introduced into the mixed solution and then added into water at a flow rate of 150-200 L / min.

[0018] The invention finds that after supercritical carbon dioxide of a certain pressure is introduced into a mixed solution, a swelling effect occurs between the supercritical carbon dioxide and the sulfone resin, and then the system is added to water at a flow rate of 10-300 L / min for precipitation, which can avoid the problem of increased oligomer content and increased D50 particle size caused by poor dispersion effect of the sulfone resin due to too low a flow rate, and can also avoid the problem of uneven particle size distribution caused by decreased flow control stability due to too high a flow rate; that is, adding the sulfone resin into water for precipitation within the flow rate range provided by the invention can effectively disperse the sulfone resin, so that the sulfone resin is precipitated in water into a micro powder form with a small D50 particle size and uniform particle size distribution, and the oligomer content is low and the purity is high; especially when the flow rate is further selected to be 150-200 L / min, the comprehensive performance of the obtained product is better.

[0019] As a preferred embodiment of the preparation method of the present invention, the good solvent includes N-methylpyrrolidone and N,N-dimethylformamide, and the mass ratio of N-methylpyrrolidone to N,N-dimethylformamide is 1:(5-15).

[0020] Exemplarily, the mass ratio of N-methylpyrrolidone and N,N-dimethylformamide can be any point value or any two point range values ​​between 1:(5-15), such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc.

[0021] Preferably, the good solvent comprises N-methylpyrrolidone and N,N-dimethylformamide, and the mass ratio of N-methylpyrrolidone to N,N-dimethylformamide is 1:(8-10).

[0022] The present invention has found that the addition of a specific type of good solvent can effectively improve the solubility of the sulfone resin, thereby facilitating the subsequent swelling reaction with supercritical carbon dioxide and facilitating the subsequent dispersion in precipitant water, thereby helping to reduce the D50 particle size of the generated sulfone resin, improving the uniformity of particle size distribution, reducing the oligomer content, and improving the purity of the product; in particular, when the good solvent is further selected as a mixture of N-methylpyrrolidone and N,N-dimethylformamide in a mass ratio of 1:(8-10), the comprehensive effect of the obtained sulfone resin is better.

[0023] As a preferred embodiment of the preparation method of the present invention, the dispersant includes ethylene dichloride and butyl acetate, and the mass ratio of the ethylene dichloride to butyl acetate is 1:(1-8).

[0024] Exemplarily, the mass ratio of ethylene dichloride to butyl acetate can be any point value or any range value between 1:(1-8), such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, etc.

[0025] Preferably, the dispersant comprises ethylene dichloride and butyl acetate, and the mass ratio of the ethylene dichloride to butyl acetate is 1:(3-5).

[0026] The present invention has found that the type of dispersant affects the dispersion effect of the sulfone resin generated after the polymerization reaction in the solvent. After adding a suitable type of good solvent, the dispersant selected by the present invention can effectively disperse the sulfone resin, thereby helping to improve the micronization and purity of the sulfone resin. In particular, when the dispersant is further selected as dichloroethane and butyl acetate in a mass ratio of 1: (3-5), the comprehensive effect of the obtained product is better.

[0027] As a preferred embodiment of the preparation method of the present invention, the mass percentage of the good solvent is 5-60% based on the mass of the reaction solvent.

[0028] Exemplarily, based on the mass of the reaction solvent, the mass percentage of the good solvent can be any point value or any two point range value between 5-60%, such as 6-58%, or can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc.

[0029] Preferably, based on the mass of the reaction solvent, the mass percentage of the good solvent is 30-40%, for example, 30%, 32%, 34%, 36%, 38%, 40%, etc.

[0030] The present invention has found that when the mass percentage of the good solvent is 5-60%, especially 30-40%, it can have good interaction with the dispersant on the basis of better dissolution of the sulfone resin, and can also avoid the influence of excessive addition of the good solvent on the purity, that is, the comprehensive performance of the obtained product is better.

[0031] As a preferred embodiment of the preparation method of the present invention, the mass percentage of the dispersant is 0.1-30% based on the mass of the reaction solvent.

[0032] Illustratively, based on the mass of the reaction solvent, the mass percentage of the dispersant can be any point value or any two point range values ​​between 0.1-30%, such as 0.5-28%, or 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, etc.

[0033] Preferably, based on the mass of the reaction solvent, the mass percentage of the dispersant is 10-15%.

[0034] The present invention has found that when the mass percentage of the dispersant is selected to be 0.1-30%, especially 10-15%, it can not only improve the dispersion effect of the sulfone resin after dissolution in a good solvent, but also effectively control the oligomer content in the subsequently obtained sulfone resin micropowder, thereby improving the comprehensive performance of the product.

[0035] As a preferred embodiment of the preparation method of the present invention, in the step (2), the temperature of the reaction system after cooling is 40-80°C.

[0036] The present invention has found that further cooling the reaction system to 40-80°C and then adding a good solvent and a dispersant can help the good solvent and the dispersant to play their respective roles more effectively, thereby improving the overall performance of the product.

[0037] As a preferred embodiment of the preparation method of the present invention, the temperature of the supercritical carbon dioxide is 40-80°C.

[0038] Exemplarily, the temperature of the supercritical carbon dioxide may be any point value or any two point range value between 40-80°C, such as 40°C, 50°C, 60°C, 70°C, 80°C, etc.

[0039] As a preferred embodiment of the preparation method of the present invention, in the step (3), the holding time is 0.5-6h.

[0040] Exemplarily, the holding time may be any point value or any two point range values ​​between 0.5-6 hours, such as 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, etc.

[0041] Preferably, the holding time is 2-3 hours.

[0042] The present invention has found that maintaining a suitable time after the introduction of carbon dioxide can reduce the introduction of impurities on the basis of fully swelling the sulfone resin, thereby improving the comprehensive performance of the product.

[0043] As a preferred embodiment of the preparation method of the present invention, in the step (2), the stirring time after adding the good solvent and the dispersant in sequence is 0.5-2h, the stirring speed is 200-400r / min, and the temperature of the material during stirring is 180-200°C.

[0044] As a preferred embodiment of the preparation method of the present invention, in the step (3), the mass percentage of water is 400-600% based on the mass of the reaction solvent.

[0045] The present invention has found that water with a suitable mass percentage can effectively precipitate sulfone resins, helping to achieve the excellent comprehensive effects of sulfone resins.

[0046] As a preferred embodiment of the preparation method of the present invention, in the step (3), the boiling time is 0.5-2h.

[0047] As a preferred embodiment of the preparation method of the present invention, in the step (3), the solid-liquid separation also includes a washing process of the filter residue, the washing number of times is 8-10 times, and the washing is washed until the washing liquid does not become turbid when detected by silver nitrate.

[0048] The preparation method of sulfone resin micropowder provided by the present invention is suitable for the preparation of all sulfone resins, for example, the sulfone resin can be bisphenol A type polysulfone, polyether sulfone, polyphenyl sulfone, etc. In the salt-forming reaction and polymerization reaction stages in the preparation process, the sulfone resin reaction monomer, azeotropy agent, salt-forming agent and reaction solvent used in the present invention are all substances conventionally used in the art.

[0049] Exemplarily, when the sulfone resin is bisphenol A type polysulfone, the reaction monomers are 4,4'-dichlorodiphenyl sulfone and 2,2-bis(4-hydroxyphenyl)propane, the entrainer is xylene, the salt-forming agent is potassium hydroxide, and the reaction solvent is cyclopentane sulfone, N,N-dimethylacetamide and / or dimethyl sulfoxide; when the sulfone resin is polyethersulfone, the reaction monomers are 4,4'-dichlorodiphenyl sulfone and 4,4'-dihydroxydiphenyl sulfone, the entrainer is xylene, the salt-forming agent is sodium carbonate, and the reaction solvent is cyclopentane sulfone, N,N-dimethylformamide and / or diphenyl sulfone; when the sulfone resin is polyphenylsulfone, the reaction monomers are 4,4'-dichlorodiphenyl sulfone and 4,4'-biphenol, the entrainer is xylene, the salt-forming agent is sodium carbonate, and the reaction solvent is cyclopentane sulfone and / or N,N-dimethylformamide.

[0050] Preferably, in the salt-forming reaction stage, the temperature of the salt-forming reaction is 180-220° C., and the time of the salt-forming reaction is 4-6 h.

[0051] Preferably, in the polymerization reaction stage, the polymerization reaction temperature is 230-240° C., and the polymerization reaction time is 2-3 h.

[0052] Preferably, the inert gas environment includes a nitrogen environment or a rare gas environment.

[0053] In a second aspect of the present invention, the present invention provides a sulfone resin micropowder, wherein the sulfone resin micropowder is prepared by the preparation method of the present invention.

[0054] As a preferred embodiment of the sulfone resin micropowder of the present invention, the sulfone resin micropowder has a D50 particle size of ≤15 μm, a particle size distribution uniformity P of 1.03-1.54, and an oligomer content of ≤1.47 wt%.

[0055] In a third aspect of the present invention, the present invention provides a coating, wherein the coating comprises the sulfone resin powder of the present invention.

[0056] Illustratively, the coating may be a powder coating.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] In the preparation method of a sulfone resin micropowder provided by the present invention, the temperature is lowered after the polymerization reaction is completed, and a good solvent is added to the reaction system after the temperature is lowered, which can effectively improve the solubility of the sulfone resin obtained by polymerization; at the same time, adding a dispersant after adding the good solvent can more effectively improve the dispersion effect of the sulfone resin obtained by polymerization; so that when supercritical carbon dioxide within a certain pressure range is subsequently introduced and added to water at a specific flow rate for precipitation, the sulfone resin obtained by polymerization can be dispersed into smaller and more uniform droplets, shortening the coagulation time of the sulfone resin in water, reducing the introduction of impurities, and improving the purity of the sulfone resin. In addition, the preparation method of the sulfone resin micropowder provided by the present invention is simple to operate, does not generate other by-products, and uses less water for washing, which is conducive to actual production applications. DETAILED DESCRIPTION

[0059] 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.

[0060] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0061] Example 1

[0062] The embodiment of the present invention provides a sulfone resin powder (polyethersulfone PES), and the preparation method of the sulfone resin powder comprises the following steps:

[0063] (1) 1285g of reaction solvent (cyclopentane sulfone), sulfone resin reaction monomer (293g of 4,4'-dichlorodiphenyl sulfone and 257g of 4,4'-dihydroxydiphenyl sulfone), 111g of salt-forming agent (sodium carbonate), and 105g of entrainer (xylene) were quantitatively added to a 5L reactor, the reactor was evacuated, nitrogen was introduced for replacement three times, and the temperature was raised to 205°C under nitrogen protection for salt-forming reaction for 5h. In the salt-forming reaction, the entrainer continuously discharges the water produced by the reaction through azeotropy until no water is discharged, and the salt-forming reaction is completed; then the system was heated to 235°C for polymerization reaction for 3h;

[0064] (2) After the polymerization reaction is completed, the temperature is lowered to 60° C., and then a good solvent (based on the reaction solvent, the mass percentage of the good solvent is 30%, and the good solvent is N-methylpyrrolidone) is added to the reaction system after the temperature is lowered and stirred at a speed of 300 r / min for 1 hour, and the material temperature is maintained at 60° C.; then a dispersant (based on the reaction solvent, the mass percentage of the dispersant is 10%, and the dispersant is a mixture of 1,3-propylene glycol and ethyl acetate in a mass ratio of 1:4) is added and stirred at a speed of 300 r / min for 1 hour, and the material temperature is maintained at 60° C. to obtain a mixed solution;

[0065] (3) Supercritical carbon dioxide (pressure of 18 MPa, temperature of 60° C.) is introduced into the mixed solution and maintained for 1 hour. After maintaining for 1 hour, the mixed solution is added to a dispersion kettle containing water (the mass percentage of water is 400% based on the mass of the reaction solvent) at a flow rate of 200 L / min for precipitation, and then boiled for 1 hour, followed by solid-liquid separation, and the filter residue is collected and washed 9 times until the washing liquid is no longer turbid when detected by silver nitrate, and then the filter residue is vacuum dried to obtain sulfone resin (polyether sulfone PES) powder.

[0066] Examples 2-23 and Comparative Examples 1-5

[0067] The examples and comparative examples of the present invention explore the effects of the type and amount of good solvent, the type and amount of dispersant, the parameters of supercritical carbon dioxide, the mass percentage of precipitant water, and the flow rate. Except for the parameters in Table 1, the rest are consistent with those in Example 1; wherein the mass percentages of good solvent, dispersant, and precipitant water are all based on the mass of the reaction solvent; at the same time, the parameters of Example 1 are listed in Table 1;

[0068] Wherein, " / " in Comparative Example 1 and Comparative Example 2 respectively indicates that a certain substance is not added, that is, the difference between Comparative Example 1 and Example 1 is that a good solvent is not added, and the difference between Comparative Example 2 and Example 1 is that a dispersant is not added;

[0069] Table 1

[0070]

[0071]

[0072]

[0073] Embodiment 24

[0074] The embodiment of the present invention provides a sulfone resin powder (polyphenylsulfone PPSU), and the preparation method of the sulfone resin powder comprises the following steps:

[0075] (1) 1285g of reaction solvent (cyclopentane sulfone), 316g of 4,4'-dichlorodiphenyl sulfone and 197g of 4,4'-biphenyl diphenol, 111g of salt-forming agent (sodium carbonate), and 124g of azeotroping agent (toluene) were quantitatively added to a 5L reactor, the reactor was evacuated, nitrogen was introduced for replacement three times, and the temperature was raised to 200°C under nitrogen protection to carry out salt-forming reaction for 5h. In the salt-forming reaction, the azeotroping agent continuously discharges the water produced by the reaction through azeotropy until no water is discharged, and the salt-forming reaction is completed; then the system was heated to 235°C for polymerization reaction for 3h;

[0076] (2) After the polymerization reaction is completed, the temperature is lowered to 50° C., and then a good solvent (based on the reaction solvent, the mass percentage of the good solvent is 30%, and the good solvent is N-methylpyrrolidone) is added to the reaction system after the temperature is lowered and stirred at a speed of 300 r / min for 1 hour, and the material temperature is maintained at 50° C.; then a dispersant (based on the reaction solvent, the mass percentage of the dispersant is 10%, and the dispersant is a mixture of 1,3-propylene glycol and ethyl acetate in a mass ratio of 1:4) is added and stirred at a speed of 300 r / min for 1 hour, and the material temperature is maintained at 50° C. to obtain a mixed solution;

[0077] (3) Supercritical carbon dioxide (pressure of 18 MPa, temperature of 60° C.) is passed through the mixed solution and maintained for 1 hour, and then added to a dispersion kettle containing water (the mass percentage of water is 510% based on the mass of the reaction solvent) at a flow rate of 200 L / min for precipitation, followed by boiling for 1 hour, followed by solid-liquid separation, and the filter residue is collected and washed 9 times until the washing liquid does not become turbid when detected by silver nitrate, and then the filter residue is vacuum dried to obtain sulfone resin (polyphenylsulfone PPSU) powder.

[0078] Effect example

[0079] Effect Example of the Invention The D50 particle size, particle size distribution uniformity and purity of the sulfone resin micropowders prepared in Examples 1-24 and Comparative Examples 1-5 were investigated;

[0080] 1. The test method for D50 particle size and particle size distribution uniformity is as follows: place the sample in a dispersion medium (ethanol) and disperse the particles in ultrasound to form a uniform suspension, which is then placed in the sample cell of the Mastersizer 3000 + Lab laser particle size analyzer for testing; record the D50 particle size and calculate the particle size distribution uniformity, where the particle size distribution uniformity P = (D90-D10) / D50; the closer the P value is to 1, the better the particle size distribution uniformity, that is, the more uniform the distribution;

[0081] 2. The test method for oligomer content is: test the oligomer content (S) in the resin by gel permeation chromatography (GPC), using polystyrene or polymethyl methacrylate as the standard and THF or DMF as the mobile phase;

[0082] The results obtained are shown in Table 2;

[0083] Table 2

[0084]

[0085]

[0086] It can be seen from Table 2 that when the preparation method provided by the present invention is adopted, the obtained sulfone resin micropowder has a smaller D50 particle size and a more uniform particle size distribution, and the obtained sulfone resin micropowder has a lower oligomer content; specifically, the obtained sulfone resin micropowder has a D50 particle size between 4.43-14.77 μm, a particle size distribution uniformity between 1.03-1.54, and an oligomer content below 1.47 wt%;

[0087] It can be seen from Examples 1-8 and Comparative Example 1 that the type of good solvent and the amount of good solvent added relative to the reaction solvent will affect the comprehensive performance of the sulfone resin powder to a certain extent. When no good solvent is added after the polymerization reaction in Comparative Example 1, the D50 particle size of the obtained sulfone resin increases significantly, the uniformity of the particle size distribution deteriorates significantly, and the oligomer content also shows a certain upward trend;

[0088] It can be seen from Example 1, Examples 9-15 and Comparative Example 2 that the type of dispersant and the amount added relative to the reaction solvent will affect the comprehensive performance of the sulfone resin micropowder to a certain extent. When no dispersant is added in Comparative Example 2, the D50 particle size of the obtained sulfone resin increases significantly and the uniformity of the particle size distribution also deteriorates significantly, and the oligomer content also shows a certain upward trend;

[0089] It can be seen from Example 1, Examples 16-17 and Comparative Example 3 that the pressure of supercritical carbon dioxide affects the comprehensive properties of sulfone resins. When the pressure of supercritical carbon dioxide in Comparative Example 3 is too low, the D50 particle size of the obtained sulfone resin increases significantly, the uniformity of the particle size distribution deteriorates significantly, and the oligomer content also shows a certain upward trend;

[0090] It can be seen from Example 1, Examples 21-23 and Comparative Examples 4-5 that the flow rate at which the mixed solution flows into the precipitant water will also affect the performance of the sulfone resin. When the flow rate in Comparative Example 4 is too low or the flow rate in Comparative Example 5 is too high, the D50 particle size of the obtained sulfone resin increases sharply and the uniformity of the particle size distribution decreases significantly. At the same time, the oligomer content also shows a significant upward trend.

[0091] Finally, it should be noted that the above embodiments are intended to illustrate the technical solution 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 the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing sulfone resin micropowder, characterized in that: The preparation method comprises the following steps: (1) adding a sulfone resin reaction monomer, an azeotropic agent, and a salt-forming agent to a reaction solvent under an inert gas environment to carry out a salt-forming reaction and a polymerization reaction; (2) cooling the reaction system after the polymerization reaction is completed, and sequentially adding a good solvent and a dispersant to the reaction system after the reaction is cooled and stirring to obtain a mixed solution; (3) introducing supercritical carbon dioxide at a pressure of ≥8 MPa into the mixed solution and maintaining the pressure, and after the maintenance, adding the mixed solution to water at a flow rate of 10-300 L / min, followed by boiling, solid-liquid separation, collecting the filter residue and drying it to obtain a sulfone resin; The good solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide; The dispersant includes at least one of chloroform, ethylene dichloride, ethanol, 1,3-propylene glycol, ethyl acetate, and butyl acetate.

2. The preparation method according to claim 1, characterized in that: The good solvent comprises N-methylpyrrolidone and N,N-dimethylformamide, and the mass ratio of N-methylpyrrolidone to N,N-dimethylformamide is 1:(5-15); And / or, the dispersant comprises ethylene dichloride and butyl acetate, and the mass ratio of the ethylene dichloride to butyl acetate is 1:(1-8).

3. The preparation method according to claim 1, characterized in that: The mass percentage of the good solvent is 5-60% based on the mass of the reaction solvent; And / or, based on the mass of the reaction solvent, the mass percentage of the dispersant is 0.1-30%.

4. The preparation method according to claim 1, characterized in that: In the step (2), the temperature of the reaction system after cooling is 40-80°C.

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

6. The preparation method according to claim 1, characterized in that: In the step (3), the holding time is 0.5-6h.

7. The preparation method according to claim 1, characterized in that: In the step (3), the mass percentage of water is 400-600% based on the mass of the reaction solvent.

8. A sulfone resin powder, characterized in that: The sulfone resin powder is prepared by the preparation method according to any one of claims 1 to 7.

9. The sulfone resin fine powder according to claim 8, characterized in that: The D50 particle size of the sulfone resin micropowder is ≤15 μm, the particle size distribution uniformity P is 1.03-1.54, and the oligomer content is ≤1.47 wt%.

10. A coating, characterized in that: The invention comprises the sulfone resin powder according to any one of claims 8 to 9.

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