Purification method of high-molecular polymer and purified high-molecular polymer

Abstract

According to the purification method of the ultra-fine high-molecular polymer and the purified ultra-fine high-molecular polymer, the ultra-fine high-molecular polymer is swelled in the purification process, so that the filtering rate of a mixed solution is effectively increased, and the purification method has the advantage of high efficiency; meanwhile, the steps of multiple times of filtration and centrifugation are matched, different types of impurities in the superfine high-molecular polymer can be effectively removed, the purification degree of the purified superfine high-molecular polymer is effectively improved, compared with a traditional purification method, the yield of waste water and waste liquid can be reduced, and the method has the advantage of being environmentally friendly; the dual requirements of industrial production and environmental protection can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer purification, and in particular relates to a high molecular polymer purification method and a purified high molecular polymer. Background Art

[0002] Due to the particularity of this ultra-fine high-molecular polymer, the front-end involves a large number of chemical raw materials, a complex synthesis process, and many steps, which are often accompanied by the introduction of impurities. These impurities may come from residues of raw materials, catalysts, capping agents, unreacted monomers or side reaction products. The presence of these impurities not only affects the performance of the final product, but may also pose potential risks to the environment and human health; at the same time, the process of such high-molecular polymers in the back-end application often involves precision processing such as photolithography and laser transfer, which places high demands on their purity and cannot be purified through general industrial purification and separation methods such as sedimentation with poor solvents, mechanical crushing, grinding, etc.; although the commonly used methods in the laboratory such as rotary evaporation and crystallization can be used for purification, their efficiency is extremely low and continuous and industrial production cannot be carried out.

[0003] At present, although traditional polymer purification technologies, such as solvent extraction, precipitation, filtration and distillation, can remove impurities to a certain extent, these methods are often time-consuming and energy-consuming, with low purification efficiency, long time, industrial purification technology discharges a lot of wastewater and waste liquid, high ash content after filtration, impurities cannot be removed completely, or cleaning is not thorough; in addition, these methods may require the use of a large amount of organic solvents, which not only increases the processing cost, but also may cause pollution to the environment, low purification efficiency, long time, industrial purification technology discharges a lot of wastewater and waste liquid, high ash content after filtration, impurities cannot be removed completely, or cleaning is not thorough.

[0004] With the rise of sustainable development and green chemistry, the industry has an increasing demand for the development of new purification technologies that can effectively remove impurities without compromising polymer properties while reducing energy consumption and environmental pollution.

[0005] Therefore, developing a purification method for ultrafine high molecular polymers with high purification efficiency and reduced environmental impact is a technical problem that urgently needs to be solved in this field. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for purifying an ultrafine polymer and a purified ultrafine polymer, wherein the purification method can effectively remove impurities in the ultrafine polymer and improve the degree of purity of the ultrafine polymer, and also has the advantages of high purification efficiency and environmental friendliness, and can meet the dual needs of industrial production and environmental protection.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for purifying an ultrafine high molecular weight polymer, the method comprising the following steps:

[0009] (1) mixing an ultrafine polymer, a polar solvent A and water, and filtering to obtain a filter cake A;

[0010] (2) mixing filter cake A and poor solvent A, filtering, and obtaining filter cake B;

[0011] (3) crushing the filter cake B, mixing it with the polar solvent B, and filtering it to obtain the filter cake C;

[0012] (4) Repeat step (3) of mixing with polar solvent B and filtering until the mass percentage of oligomers, monomers and additives in the filtrate is ≤5%, thereby obtaining a target filter cake;

[0013] (5) The target filter cake is centrifuged to complete the purification of the polyolefin polymer.

[0014] The purification method provided by the present invention comprises the following steps: firstly, mixing an ultrafine high molecular polymer, a polar solvent A and water, wherein water can dissolve the inorganic reactant impurities in excess of the reaction, and the polar solvent A can dissolve some polar organic impurities, thereby obtaining a suspension, and then filtering to remove the inorganic reactant impurities and some polar organic impurities wrapped in the gaps between the ultrafine high molecular polymer particles, thereby obtaining a filter cake A; and then mixing the filter cake A with a poor solvent A. At this time, since the filter cake A still contains some by-products, unreacted monomers, oligomers and other impurities, the added poor solvent A is a good solvent for the above impurities, thereby extracting the above impurities, and at the same time, the above impurities can be gradually removed. The ultrafine high molecular polymer is precipitated from the original good solvent (mixed liquid), and swelling occurs at the same time to form a small particle encapsulation group, so that it undergoes a similar extraction effect and the polymer particles become larger through swelling, which can speed up the subsequent filtration. After filtering, most of the impurities can be removed to obtain a filter cake C; the filter cake C is then broken up and mixed and filtered again with the polar solvent B, and the above steps are repeated until the total mass percentage of oligomers, monomers and additives detected in the filtrate is not higher than 5%, and a relatively pure target filter cake can be obtained; finally, the target filter cake is centrifuged to complete the spring of the ultrafine high molecular polymer and obtain a purified ultrafine high molecular polymer.

[0015] The present invention causes the ultrafine high molecular weight polymer to swell by preferably selecting a solvent that can fully swell the ultrafine high molecular weight polymer, thereby effectively improving the filtration rate of the mixed solution, so that the purification method has the advantage of high efficiency. At the same time, with multiple filtration and centrifugation steps, different types of impurities in the ultrafine high molecular weight polymer can be effectively removed, and the purity of the ultrafine high molecular weight polymer after purification can be improved. Compared with traditional purification methods, the amount of wastewater and waste liquid generated can be reduced, and the method has the advantage of being environmentally friendly, which can meet the dual needs of industrial production and environmental protection.

[0016] It should be noted that, in the purification method provided by the present invention, the "poor solvent" refers to a solvent with a weaker solubility for extremely fine high molecular polymers, and generally the interaction parameter χ with the extremely fine high molecular polymers is close to or greater than 0.5; the "good solvent" refers to a solvent with a stronger solubility for extremely fine high molecular polymers, and the interaction parameter χ with the extremely fine high molecular polymers is less than 0.5; the specific selection of which solvent to be used as a good solvent and which solvent to be selected as a poor solvent needs to be determined according to the type of extremely fine high molecular polymers.

[0017] It should also be noted that the purification method provided by the present invention does not impose any special restrictions on the detection method used in step (4) until the mass percentage of oligomers, monomers and additives in the filtrate is ≤5%, and the UV absorption method is preferred in the present invention.

[0018] Preferably, the ultrafine high molecular polymer in step (1) comprises any one of ultrafine polyamide high molecular polymer, ultrafine polyurethane high molecular polymer, ultrafine styrene-maleimide high molecular polymer, ultrafine acrylate high molecular polymer or ultrafine triazene high molecular polymer, or a combination of at least two thereof.

[0019] Preferably, the D of the ultrafine polymer in step (1) is 50 The particle size is 50 to 250 nm, for example, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, 190 nm, 210 nm, 230 nm or 250 nm.

[0020] Preferably, the ultrafine high molecular polymer in step (1) is obtained by filtering the ultrafine high molecular polymer solution obtained at the synthesis end.

[0021] The present invention does not impose any special restrictions on the method for synthesizing the ultrafine high molecular weight polymer, and the method may be carried out using conventional synthesis methods in the art.

[0022] Preferably, based on the weight of the ultrafine high molecular weight polymer in step (1) being 1 kg, the total amount of the polar solvent A and water in step (1) is 5 to 10 L, for example, 5 L, 6 L, 7 L, 8 L, 9 L or 10 L.

[0023] Preferably, the volume ratio of the polar solvent to water in step (1) is 1:(1-6), for example, 1:1, 1:2, 1:3, 1:4, 1:5 or 1:6.

[0024] Preferably, the polar solvent A in step (1) comprises any one of methanol, ethanol or isopropanol, or a combination of at least two of them.

[0025] Preferably, the mixing in step (1) is ultrasonic mixing.

[0026] Preferably, the power of the ultrasonic mixing is 50-70 W, for example, 50 W, 52 W, 54 W, 56 W, 58 W, 60 W, 62 W, ​​64 W, 66 W, 68 W or 70 W.

[0027] Preferably, the ultrasonic mixing time is 2 to 4 min, for example, 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min or 3.8 min.

[0028] Preferably, the filtration in step (1) is pressure filtration.

[0029] Preferably, the pressure of the pressurized filtration is 0.1-0.25 MPa, for example, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa or 0.25 MPa.

[0030] Preferably, based on the mass of the filter cake A in step (2) being 1 kg, the amount of the poor solvent A in step (2) is 1 to 4 L, for example, 1 L, 1.5 L, 2 L, 2.5 L, 3 L, 3.5 L or 4 L.

[0031] Preferably, the poor solvent A in step (2) comprises any one of alkanes, ethers, secondary alcohols or primary alcohols, or a combination of at least two of them.

[0032] Preferably, the mixing in step (2) is ultrasonic mixing.

[0033] Preferably, the power of the ultrasonic mixing is 50-70 W, for example, 50 W, 52 W, 54 W, 56 W, 58 W, 60 W, 62 W, ​​64 W, 66 W, 68 W or 70 W.

[0034] Preferably, the ultrasonic mixing time is 2 to 4 min, for example, 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min or 3.8 min.

[0035] Preferably, the filtration in step (2) is pressure filtration.

[0036] Preferably, the pressure of the pressurized filtration is 0.1-0.25 MPa, for example, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa or 0.25 MPa.

[0037] Preferably, based on the mass of the filter cake B in step (3) being 1 kg, the amount of the good solvent B in step (3) is 5 to 10 L, for example, 5 L, 6 L, 7 L, 8 L, 9 L or 10 L.

[0038] Preferably, the polar solvent in step (3) comprises secondary alcohol and / or primary alcohol.

[0039] Preferably, the mixing in step (3) is ultrasonic mixing.

[0040] Preferably, the power of the ultrasonic mixing is 50-70 W, for example, 50 W, 52 W, 54 W, 56 W, 58 W, 60 W, 62 W, ​​64 W, 66 W, 68 W or 70 W.

[0041] Preferably, the ultrasonic mixing time is 2 to 4 min, for example, 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min or 3.8 min.

[0042] Preferably, the filtration in step (3) is pressure filtration.

[0043] Preferably, the pressure of the pressurized filtration is 0.1-0.25 MPa, for example, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa or 0.25 MPa.

[0044] Preferably, the centrifugal treatment method in step (5) specifically comprises the following steps:

[0045] (5A) dissolving the target filter cake in a good solvent, removing insoluble matter by centrifugation, and obtaining a supernatant;

[0046] (5B) mixing the supernatant and the poor solvent B, filtering, and obtaining a filter cake;

[0047] (5C) adding water to the filter cake for washing, filtering, and completing the centrifugation treatment.

[0048] Preferably, the mixing in step (5B) is carried out under stirring conditions.

[0049] Preferably, the mixing time in step (5B) is 0.5 to 2.5 h, for example, 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h, 1.5 h, 1.7 h, 1.9 h, 2.1 h, 2.3 h or 2.5 h.

[0050] Preferably, the centrifugal treatment in step (5) further includes a drying step.

[0051] Preferably, the drying method specifically comprises: first drying at normal pressure, 50-100°C (for example, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, etc.) for 8-24h (for example, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, etc.), and then continuing drying at 0.1-130Pa (for example, 0.1Pa, 0.5Pa, 1Pa, 5Pa, 10Pa, 20Pa, 40Pa, 60Pa, 80Pa, 100Pa or 120Pa, etc.), 50-100°C (for example, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, etc.) for 12-48h (for example, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, etc.) to constant weight to complete the drying.

[0052] As a preferred technical solution of the present invention, the purification method comprises the following steps:

[0053] (1) first filtering the ultrafine polymer solution obtained from the synthesis end, then ultrasonically mixing the ultrafine polymer obtained from the filtration, polar solvent A and water at 50-70W for 2-4 minutes, and finally filtering under pressure at 0.1-0.25MPa to obtain filter cake A;

[0054] (2) mixing filter cake A and poor solvent A by ultrasonic mixing at 50 to 70 W for 2 to 4 minutes, and filtering under pressure at 0.1 to 0.25 MPa to obtain filter cake B;

[0055] (3) crushing the filter cake B, mixing it with the polar solvent B under ultrasonic conditions at 50 to 70 W for 2 to 4 minutes, and filtering it under pressure at 0.1 to 0.25 MPa to obtain a filter cake C;

[0056] (4) repeating step (3) of ultrasonically mixing with polar solvent B at 50 to 70 W for 2 to 4 min, and filtering under pressure at 0.1 to 0.25 MPa, until the total mass percentage of oligomers, monomers and additives in the filtrate is ≤5%, thereby obtaining a target filter cake;

[0057] (5) First, the target filter cake is dissolved in a good solvent, and the insoluble matter is removed by centrifugation. The supernatant obtained is mixed with a poor solvent B for 0.5 to 2.5 hours, and filtered. Finally, water is added to the obtained filter cake for washing, and filtered again to obtain a wet ultrafine high molecular polymer;

[0058] (6) drying the wet ultrafine polymer at normal pressure and 50-100° C. for 8-24 h, and then drying at 0.1-130 Pa and 50-100° C. for 12-48 h until constant weight is achieved, thereby completing the purification of the ultrafine polymer.

[0059] In a second aspect, the present invention provides a purified ultrafine high molecular polymer, wherein the purified ultrafine high molecular polymer is obtained by treatment using the purification method described in the first aspect.

[0060] Preferably, the D of the purified ultrafine polymer 50 The particle size is 50 to 250 nm, for example, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, 190 nm, 210 nm, 230 nm or 250 nm.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The purification method of the ultrafine high molecular polymer provided by the present invention causes the ultrafine high molecular polymer to swell during the purification process, thereby effectively improving the filtration rate of the mixed solution, so that the purification method has the advantage of high efficiency. At the same time, with multiple filtration and centrifugation steps, different types of impurities in the ultrafine high molecular polymer can be effectively removed, and the purity of the ultrafine high molecular polymer after purification can be improved. Compared with traditional purification methods, the amount of wastewater and waste liquid generated can be reduced, and it has the advantage of being environmentally friendly and can meet the dual needs of industrial production and environmental protection. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0064] Synthesis example 1

[0065] A triazene polymer solution, wherein the D 50 The particle size is 150nm, and the preparation method comprises the following steps:

[0066] (1) 1 L of 37% concentrated hydrochloric acid and 0.5 mol of 4,4'-diaminodiphenyl sulfone were added to 0.5 L of water, and the mixture was stirred and dispersed at 0°C until uniform. Then, 2 L of 0.5 M sodium nitrite aqueous solution was added dropwise, and the mixture was stirred for 120 min to obtain a diazonium salt aqueous solution.

[0067] 0.5 mol of N,N'-dibenzylethylenediamine, 2 L of 10% hydrochloric acid aqueous solution, 100 g of crushed ice and 0.3 L of a mixed solvent of pentane and hexane were stirred magnetically for 30 min to obtain a secondary diamine aqueous solution;

[0068] (2) The diazonium salt aqueous solution and the secondary diamine aqueous solution described in step (1) are sequentially added into a reaction container and mechanically stirred, and then 0.8 L of phosphate buffer solution (pH 9) and 1.5 L of 35% by weight sodium hydroxide solution are gradually added at 0° C., and the temperature is gradually raised to room temperature for reaction for 90 minutes. After the reaction is completed, the mixture is allowed to stand at room temperature overnight to obtain the triazene polymer solution.

[0069] Synthesis example 2

[0070] A polyurethane polymer solution, wherein the D 50 The particle size is 200nm, and the preparation method comprises the following steps:

[0071] (1) Dissolve 650 g of highly hydrophilic polycaprolactone monomer in 20,000 g of toluene, control the temperature at 25° C., and fill with nitrogen to protect against oxidation;

[0072] (2) 2000 g HDI was added in batches, and polycondensation reaction was carried out at 25° C. for 24 hours to obtain the polyurethane polymer solution.

[0073] Synthesis example 3

[0074] A styrene-maleimide polymer solution, comprising a very fine styrene-maleimide polymer having a D 50 The particle size is 100 nm, and the preparation method comprises the following steps:

[0075] (1) Dissolve 700 g of styrene and 850 g of highly photosensitive maleimide in 2000 mL of cyclohexanone, control the temperature at 70° C. to allow the mixture to fully dissolve, and fill with nitrogen to protect against oxidation;

[0076] (2) adding 10 g of AIBN and conducting a polycondensation reaction at 70° C. for 12 h to obtain the styrene-maleimide polymer solution.

[0077] Example 1

[0078] A method for purifying an extremely fine triazene high molecular polymer comprises the following steps:

[0079] (1) 10 kg of the triazene polymer solution obtained in Synthesis Example 1 was ultrasonically stirred at 60 W for 3 min to fully disperse it, and then pressure filtered at 0.1 MPa. Then 0.9 kg of the filtered triazene polymer (D 50 The particle size is 150 nm), 2 L of isopropanol and 3 L of water are ultrasonically mixed at 60 W for 3 min, and then pressure filtered at 0.15 MPa to obtain filter cake A;

[0080] (2) 0.89 kg of filter cake A and 2 L of methyl tert-butyl ether were ultrasonically mixed at 60 W for 3 min, and then pressure filtered at 0.15 MPa to obtain filter cake B;

[0081] (3) 0.88 kg of filter cake B was placed in a large-scale wall-breaking machine, the agglomerated polymer was completely broken up, and then ultrasonically mixed with 5 L of isopropanol at 60 W for 3 min, and then pressure filtered at 0.15 MPa to obtain filter cake C;

[0082] (4) repeating step (3) of ultrasonically mixing with isopropanol at 60 W for 3 min and filtering under pressure at 0.15 MPa for 3 times until the mass percentage of oligomers, monomers and additives in the filtrate is 4%, thereby obtaining a target filter cake;

[0083] (5) 0.86 kg of the target filter cake was dissolved in 1 L of acetone, and the insoluble matter was removed by centrifugation. 1.5 L of the obtained supernatant was mixed with 5 L of methyl tert-butyl ether for 1 h, and filtered. 5 L of water was added to 0.85 kg of the obtained filter cake for washing, and filtered to obtain a wet ultrafine high molecular polymer;

[0084] (6) drying the wet ultrafine polymer at normal pressure and 80° C. for 20 h, and then drying it at 10 Pa and 80° C. for 20 h until constant weight is reached, thereby completing the purification of the ultrafine triazene polymer to obtain a purified ultrafine triazene polymer.

[0085] Example 2

[0086] A method for purifying an ultrafine polyurethane polymer, which differs from Example 1 in that the polyurethane polymer solution provided in Synthesis Example 2 is used to replace the triazene polymer solution provided in Synthesis Example 1, and other substances, amounts and steps are the same as those in Example 1.

[0087] Example 3

[0088] A method for purifying an extremely fine styrene-maleimide polymer, which differs from Example 1 in that the styrene-maleimide polymer solution provided in Synthesis Example 3 is used to replace the triazene polymer solution provided in Synthesis Example 1, and other substances, amounts and steps are the same as those in Example 1.

[0089] Example 4

[0090] A method for purifying an ultrafine high molecular weight polymer, which differs from Example 1 in that the amount of methyl tert-butyl ether used in step (2) is 1.5 L, and the other substances, amounts and steps are the same as those in Example 1.

[0091] Example 5

[0092] A method for purifying an ultrafine high molecular weight polymer, which differs from Example 1 in that the amount of methyl tert-butyl ether used in step (2) is 3 L, and the other substances, amounts and steps are the same as those in Example 1.

[0093] Comparative Example 1

[0094] A method for purifying an ultrafine high molecular weight polymer, which differs from Example 1 in that step (2) is not performed, and step (3) is performed directly after step (1), and other substances, amounts and steps are the same as those in Example 1.

[0095] Performance Test:

[0096] (1) Purity: The purity of a sample is analyzed by heating the sample and measuring the change in sample mass with temperature.

[0097] (2) Molecular weight distribution: PDI value was measured by GPC.

[0098] (3) Filtration efficiency: refers to the filtration in step (3), and is defined as fast when the filtration time for 1000 g of filter cake is ≤ 0.5 h, otherwise it is slow.

[0099] The purified ultrafine polymers provided in Examples 1 to 5 and Comparative Example 1 were tested according to the above test method. The test results are shown in Table 1:

[0100] Table 1

[0101] Purification degree / % Molecular weight distribution Filtration efficiency Example 1 97 1.38 quick Example 2 97 1.45 quick Example 3 98 1.68 quick Example 4 95 1.66 quick Example 5 98 1.28 quick Comparative Example 1 92 1.31 slow

[0102] From the data in Table 1, we can see that:

[0103] The products obtained by the purification methods provided in Examples 1 to 5 have a higher degree of purification, a molecular weight distribution of 1.28 to 1.68, and a higher filtration efficiency; while the product obtained by the purification method provided in Comparative Example 1 has a lower degree of purification, and a lower filtration efficiency.

[0104] The applicant declares that the present invention illustrates a method for purifying ultrafine polymers and purifying ultrafine polymers through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for purifying ultrafine high molecular polymers, characterized in that: The purification method comprises the following steps: (1) mixing an ultrafine polymer, a polar solvent A and water, and filtering to obtain a filter cake A; (2) mixing filter cake A and poor solvent A, filtering, and obtaining filter cake B; (3) crushing the filter cake B, mixing it with the polar solvent B, and filtering it to obtain the filter cake C; (4) Repeat step (3) of mixing with polar solvent B and filtering until the total mass percentage of oligomers, monomers and additives in the filtrate is ≤5%, thereby obtaining a target filter cake; (5) The target filter cake is centrifuged to complete the purification of the ultrafine high molecular polymer.

2. The purification method according to claim 1, characterized in that The ultrafine high molecular polymer in step (1) includes any one of ultrafine polyamide high molecular polymer, ultrafine polyurethane high molecular polymer, ultrafine styrene-maleimide high molecular polymer, ultrafine acrylate high molecular polymer or ultrafine triazene high molecular polymer, or a combination of at least two thereof; Preferably, the D of the ultrafine polymer in step (1) is 50 Particle size is 50~250nm; Preferably, the ultrafine high molecular polymer in step (1) is obtained by filtering the ultrafine high molecular polymer solution obtained at the synthesis end.

3. The purification method according to claim 1 or 2, characterized in that Based on the weight of the ultrafine high molecular weight polymer in step (1) being 1 kg, the total amount of the polar solvent A and water in step (1) is 5 to 10 L; Preferably, the volume ratio of the polar solvent A to water in step (1) is 1:(1-6); Preferably, the polar solvent A in step (1) comprises any one of methanol, ethanol or isopropanol, or a combination of at least two thereof; Preferably, the mixing in step (1) is ultrasonic mixing; Preferably, the power of the ultrasonic mixing is 50-70W, and the time is 2-4min; Preferably, the filtration in step (1) is pressure filtration; Preferably, the pressure of the pressure filtration is 0.1-0.25 MPa.

4. The purification method according to any one of claims 1 to 3, characterized in that Based on the weight of the filter cake A in step (2) being 1 kg, the amount of the poor solvent A in step (2) is 1 to 4 L; Preferably, the poor solvent A in step (2) comprises any one or a combination of at least two of alkanes, ethers, secondary alcohols or primary alcohols; Preferably, the mixing in step (2) is ultrasonic mixing; Preferably, the power of the ultrasonic mixing is 50-70W, and the time is 2-4min; Preferably, the filtration in step (2) is pressure filtration; Preferably, the pressure of the pressure filtration is 0.1-0.25 MPa.

5. The purification method according to any one of claims 1 to 4, characterized in that: Based on the weight of the filter cake B in step (3) being 1 kg, the amount of the polar solvent B in step (3) is 5 to 10 L; Preferably, the polar solvent B in step (3) comprises secondary alcohol and / or primary alcohol; Preferably, the mixing in step (3) is ultrasonic mixing; Preferably, the power of the ultrasonic mixing is 50-70W, and the time is 2-4min; Preferably, the filtration in step (3) is pressure filtration; Preferably, the pressure of the pressure filtration is 0.1-0.25 MPa.

6. The purification method according to any one of claims 1 to 5, characterized in that: The centrifugal treatment method in step (5) specifically comprises the following steps: (5A) dissolving the target filter cake in a good solvent, removing insoluble matter by centrifugation, and obtaining a supernatant; (5B) mixing the supernatant and the poor solvent B, filtering, and obtaining a filter cake; (5C) adding water to the filter cake for washing, filtering, and completing the centrifugation treatment.

7. The purification method according to any one of claims 1 to 6, characterized in that: Step (5) further comprises a drying step after the centrifugal treatment; Preferably, the drying method specifically includes: first drying at normal pressure and 50-100° C. for 8-24 hours, and then continuing drying at 0.1-130 Pa and 50-100° C. for 12-48 hours until constant weight is reached to complete the drying.

8. The purification method according to any one of claims 1 to 7, characterized in that The purification method comprises the following steps: (1) First, the D obtained at the synthesis end 50 The ultrafine polymer solution with a particle size of 50 to 250 nm is filtered, and then the ultrafine polymer obtained by filtration, polar solvent A and water are ultrasonically mixed at 50 to 70W for 2 to 4 minutes, and finally filtered under pressure at 0.1 to 0.25MPa to obtain filter cake A; (2) mixing filter cake A and poor solvent A by ultrasonic mixing at 50 to 70 W for 2 to 4 minutes, and filtering under pressure at 0.1 to 0.25 MPa to obtain filter cake B; (3) crushing the filter cake B, mixing it with the polar solvent B under ultrasonic conditions at 50 to 70 W for 2 to 4 minutes, and filtering it under pressure at 0.1 to 0.25 MPa to obtain a filter cake C; (4) repeating step (3) of ultrasonically mixing with polar solvent B at 50-70W for 2-4 minutes and filtering under pressure at 0.1-25MPa until the total mass percentage of oligomers, monomers and additives in the filtrate is ≤5%, thereby obtaining a target filter cake; (5) First, the target filter cake is dissolved in a good solvent, and the insoluble matter is removed by centrifugation. The supernatant obtained is mixed with a poor solvent B for 0.5 to 2.5 hours, and filtered. Finally, water is added to the obtained filter cake for washing, and filtered again to obtain a wet ultrafine high molecular polymer; (6) drying the wet ultrafine polymer at normal pressure and 50-100° C. for 8-24 h, and then drying at 0.1-130 Pa and 50-100° C. for 12-48 h until constant weight is achieved, thereby completing the purification of the ultrafine polymer.

9. A method for purifying ultrafine high molecular polymers, characterized in that: The purified ultrafine high molecular weight polymer is obtained by treatment with the purification method according to any one of claims 1 to 8.

10. The purified ultrafine high molecular polymer according to claim 9, characterized in that: The purified ultrafine polymer D 50 The particle size is 50~250nm.