Sulfone polymer and preparation method thereof

Abstract

The invention discloses a sulfone polymer and a preparation method thereof.The preparation method of the sulfone polymer comprises the following steps that S1, a diphenol monomer, a disulfone monomer and a salt-forming agent are added into a solvent, then heating reflux is conducted for a salt-forming reaction, and then a polymerization reaction is conducted; s2, adding an end-capping reagent into a system in S2, and carrying out an end-capping reaction to obtain a sulfone polymer; wherein the salt-forming agent in the step S1 is sodium carbonate and / or sodium bicarbonate, and the particle size D50 is less than or equal to 100 microns. The method can effectively improve the rate of polymerization reaction and improve the production efficiency. The content of the impurity 4-chloro-4 '-hydroxydiphenyl sulfone in the prepared sulfone polymer is lower than 30 ppm, and the yellowness of the product can be effectively reduced.

Description

Technical Field

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

[0002] In the field of polymer synthesis, aromatic sulfone polymers are an important class of polymer materials. Due to their excellent high temperature resistance, mechanical strength, chemical corrosion resistance, hydrolysis resistance, radiation resistance, etc., they are widely used in electronics, automobiles, aerospace, medical food and other fields.

[0003] In the preparation process of aromatic sulfone polymers, the selection and use of salt-forming agents have a crucial influence on the rate of polymerization and the quality of products. In the existing technology, sodium carbonate is one of the most commonly used salt-forming agents, and its function is to react with phenol monomers to form phenol salts, and phenol salts react with dichlorodiphenyl sulfone to form polymers by nucleophilic substitution. Although the existing technology can use sodium carbonate or potassium carbonate as salt-forming agents to prepare aromatic sulfone polymers, the technology still has problems or disadvantages such as high by-product content and poor product quality.

[0004] Therefore, in the production of sulfone polymers, how to reduce the content of by-products and improve product quality is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention aims to provide a sulfone polymer and a preparation method thereof. In the preparation process of the sulfone polymer, the method uses sodium carbonate or sodium bicarbonate with a particle size D50 of less than 100 μm as a salt-forming agent, which can effectively increase the rate of the polymerization reaction and improve the production efficiency. The content of the impurity 4-chloro-4'-hydroxydiphenyl sulfone in the sulfone polymer thus prepared is less than 30 ppm, which can effectively reduce the yellowness of the product.

[0006] The inventor of the present application has experimentally found that in the preparation process of sulfone polymer, the particle size of salt-forming agent (such as sodium carbonate) can have an impact on polymerization reaction and side reaction. The larger the particle size of salt-forming agent, the smaller its specific surface area, and the smaller the contact area with the monomer, which can cause the polymerization reaction rate to decrease, and the extension of salt-forming time can cause the increase of side reaction, and by-products can cause biocompatibility to decrease, and optical performance decreases, etc. At the same time, the type selection of salt-forming agent can affect the polysulfone product quality. Therefore, in the process of preparing sulfone polymer, select suitable salt-forming agent category and particle size, can accelerate the salt-forming reaction rate, reduce system side reaction, especially can reduce the impurity 4-chloro-4 '-hydroxy diphenyl sulfone produced by the reaction of salt-forming agent sodium carbonate and monomer dichloro diphenyl sulfone, thereby improve the overall performance of polymer.

[0007] On the one hand, the present invention finds that by reducing the particle size of the salt-forming agent, such as reducing it to less than 100 μm, the synthesis rate of the sulfone polymer can be accelerated. For example, using 45 μm sodium carbonate as the salt-forming agent, the salt-forming time can be shortened to 3 hours, which is 2 hours shorter than using 180 μm sodium carbonate. This shows that by optimizing the particle size of the salt-forming agent, the rate of the polymerization reaction can be effectively increased, thereby improving production efficiency.

[0008] On the other hand, the present invention also found that by reducing the particle size of the salt-forming agent and limiting sodium carbonate and sodium bicarbonate as salt-forming agents, the impurity 4-chloro-4'-hydroxydiphenyl sulfone content of the sulfone polymer can be reduced, thereby reducing the yellowness index of the product. For example, by using sodium carbonate with a D50 of 45 μm as a salt-forming agent, the content of 4-chloro-4'-hydroxydiphenyl sulfone in the product can be reduced to 15ppm. In contrast, by using sodium carbonate with a D50 of 180 μm, the content of 4-chloro-4'-hydroxydiphenyl sulfone in the product is 50ppm. This shows that by using sodium carbonate and sodium bicarbonate as salt-forming agents and optimizing the particle size, the quality of the product can be effectively improved, thereby improving the performance and application value of the product.

[0009] To achieve the above-mentioned object of the invention, the present invention adopts the following technical solution.

[0010] One of the objects of the present invention is to provide a method for preparing a sulfone polymer, comprising the following steps:

[0011] S1: adding diphenol monomer, disulfone monomer and salt-forming agent into a solvent, then heating under reflux to perform salt-forming reaction, and then performing polymerization reaction;

[0012] S2: adding a capping agent to the S2 system to carry out a capping reaction to obtain a sulfone polymer;

[0013] Wherein, the salt-forming agent in step S1 is sodium carbonate and / or sodium bicarbonate, and the particle size D50 is ≤100 μm.

[0014] In a specific embodiment, the diphenol monomer in step S1 is selected from one or more of bisphenol A, bisphenol S, and 4,4′-biphenol;

[0015] The disulfone monomer is selected from one or more of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0016] In a specific embodiment, the molar ratio of the diphenol monomer to the disulfone monomer in step S1 is 1:1.0-1.03.

[0017] In a specific embodiment, the particle size of the salt-forming agent in step S1 is D50≤100 μm, preferably D50≤80 μm;

[0018] Preferably, the salt-forming agent is selected from one or more of sodium carbonate and sodium bicarbonate, preferably sodium carbonate;

[0019] Preferably, the amount of the salt-forming agent added is 1.05 to 1.3 times the molar amount of the diphenol monomer.

[0020] In a specific embodiment, the solvent in step S1 is selected from one or more of sulfolane, diphenyl sulfone, N,N-dimethylacetamide, and N-methylpyrrolidone, preferably one or more of sulfolane, N-methylpyrrolidone, and N,N-dimethylacetamide;

[0021] Preferably, based on the total mass of the diphenol monomer and the disulfone monomer, the mass proportion of the solvent is 45-80%.

[0022] In a specific embodiment, in the salt-forming reaction in step S1, the reflux reaction temperature is 140 to 220° C., and the reflux reaction time is 2 to 6 hours.

[0023] In a specific embodiment, the polymerization reaction in step S1 is carried out at a temperature of 160 to 230° C. and for a time of 2 to 48 hours.

[0024] In a specific embodiment, in step S1, a water-carrying agent may be added during the salt-forming reaction under heating and reflux. Specifically, the diphenol monomer, the disulfone monomer, and the salt-forming agent are added to the solvent, and then the water-carrying agent is added under stirring, and the salt-forming reaction is carried out under heating and reflux. The temperature is then increased to evaporate the water-carrying agent, and then a polymerization reaction is carried out.

[0025] The water-carrying agent is selected from one or more of toluene, xylene, o-xylene, chlorobenzene, and mesitylene, preferably toluene and xylene; preferably, the amount of the water-carrying agent added is 10-50% of the mass of the solvent.

[0026] In a specific embodiment, the end-capping agent in step S2 is selected from one or more of methyl chloride, chloromethyl methyl ether, 4-fluorobenzophenone, and 3,4-difluorobenzophenone, preferably methyl chloride;

[0027] Preferably, the amount of the end-capping agent added is 2-10% of the molar amount of the diphenol monomer in step S1.

[0028] In a specific embodiment, the end-capping reaction in step S2 is carried out at a temperature of 160 to 180° C. and for a time of 0.5 to 2 h.

[0029] In a specific embodiment, the reactions in step S1 and step S2 are both carried out in a protective gas environment, such as a nitrogen environment.

[0030] In a specific embodiment, after the end-capping reaction in step S2 is completed, conventional operations in the fields of filtration, crushing, water washing, and vacuum drying are also included.

[0031] The second object of the present invention is to provide a sulfone polymer prepared by the method described above.

[0032] The molecular weight distribution of the sulfone polymer is ≤2.0, preferably 1.5 to 1.9.

[0033] The weight average molecular weight of the sulfone polymer is between 50,000 and 150,000 g / mol, preferably between 60,000 and 100,000 g / mol. The content of 4-chloro-4'-hydroxydiphenyl sulfone as an impurity in the sulfone polymer is less than 30 ppm, and the yellowness index of the product is ≤8.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention discovers for the first time the influence of the particle size of the salt-forming agent on the polymerization rate and product quality of the sulfone polymer, and based on this, proposes a solution for optimizing the particle size of the salt-forming agent. By selecting sodium carbonate and sodium bicarbonate with D50 < 100 μm as the salt-forming agent, the content of 4-chloro-4'-hydroxydiphenyl sulfone in the prepared sulfone polymer is less than 30 ppm, which can significantly improve product performance and has a low yellowness index, making it more suitable for applications in high-end fields, such as optical materials, medical devices and other fields. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described in more detail below. The following examples will further illustrate the method provided by the present invention. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention is not limited to the listed embodiments, and also should be included in any other known changes within the scope of the rights claimed by the present invention.

[0037] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0038] The sulfone polymer provided by the present invention has a weight average molecular weight between 50,000 and 150,000 g / mol, for example, the weight average molecular weight is 50,000 g / mol, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 110,000 g / mol, 120,000 g / mol, 130,000 g / mol, 140,000 g / mol, 150,000 g / mol, etc., preferably between 60,000 and 100,000 g / mol.

[0039] Furthermore, the sulfone polymer has a product yellowness index of ≤8, for example, 8.0, 7.8, 7.5, 7.3, 7.0, 6.5, 6.0, 5.5, 5.0, 4.0 or less.

[0040] Meanwhile, the molecular weight distribution of the sulfone polymer provided by the present invention is less than 2.0, for example, 1.9, 1.8, 1.7, 1.6, 1.5, etc., preferably 1.5 to 1.9.

[0041] An exemplary preparation method is provided below, but does not constitute any limitation.

[0042] Specifically, a method for preparing a sulfone polymer comprises the following steps:

[0043] Dispersing diphenol monomer, disulfone monomer, and sodium carbonate and / or sodium bicarbonate with a particle size D50≤100 μm as a salt-forming agent in a solvent, then adding a water-carrying agent to a reaction kettle under stirring, heating and reflux to perform a salt-forming reaction, then raising the temperature to completely evaporate the water-carrying agent in the reaction kettle, and starting a polymerization reaction; after the polymerization reaction, reducing the stirring speed, then adding a capping agent to perform a capping reaction, and then filtering the reaction liquid, crushing, washing with water, and vacuum drying to obtain a sulfone polymer.

[0044] Wherein, the particle size D50 of the salt-forming agent is ≤100 μm, such as 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 5 μm, 1 μm, etc., preferably D50 ≤ 80 μm Wherein, the disulfone monomer is selected from one or more of bisphenol A, bisphenol S, and 4,4′-biphenyl diphenol;

[0045] The monomer is selected from one or more of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone, preferably 4,4'-dichlorodiphenyl sulfone;

[0046] The salt-forming agent is selected from one or more of sodium carbonate and sodium bicarbonate, preferably sodium carbonate;

[0047] The solvent is selected from one or more of sulfolane, diphenyl sulfone, N,N-dimethylacetamide, and N-methylpyrrolidone, preferably one or more of sulfolane, N-methylpyrrolidone, and N,N-dimethylacetamide;

[0048] The water-carrying agent is selected from one or more of toluene, xylene, o-xylene, chlorobenzene, and mesitylene, preferably toluene, xylene, or no water-carrying agent is used;

[0049] The end-capping agent is selected from one or more of methyl chloride, chloromethyl methyl ether, 4-fluorobenzophenone, and 3,4-difluorobenzophenone, preferably methyl chloride.

[0050] In the salt-forming reaction stage, the reaction is heated to 140-220°C for reflux reaction for 2-6 hours. The reflux temperature is, for example, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, etc., and can be set according to the boiling point of the reaction solvent, for example, lower than the boiling point of the reaction solvent; the reflux time is, for example, 2h, 3h, 4h, 5h, 6h, etc., and can be based on the fact that no water is produced.

[0051] In the salt-forming reaction process, a water-carrying agent may or may not be added. Some solvents such as N,N-dimethylacetamide and N-methylpyrrolidone have a water-carrying effect by themselves, and no additional water-carrying agent is needed. For the reaction in which a water-carrying agent is added, the operating temperature for distilling the water-carrying agent can be determined according to the boiling point, which is a conventional operation in the field and is not specifically required by the present invention.

[0052] In the polymerization reaction stage, the reaction is carried out at 160-230°C for 2-48h. For example, the polymerization reaction temperature is 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, etc., and the polymerization reaction time is 2h, 3h, 4h, 5h, 6h, 10h, 16h, 20h, 25h, 30h, 35h, 40h, 45h, 48h, etc. In the actual preparation process, the degree of polymerization reaction can also be judged by monitoring indicators such as the viscosity of the reaction system or the current value.

[0053] In the end-capping reaction stage, the reaction is carried out at 160-180°C for 0.5-2h. For example, the end-capping reaction temperature is 160°C, 165°C, 170°C, 175°C, 180°C, etc., and the end-capping reaction time is 0.5h, 0.7h, 1.0h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc.

[0054] There are no particularly strict restrictions on the temperature, time, etc. of the reaction involved in the present invention. However, since the sodium phenol salt formed by sodium carbonate / sodium bicarbonate and bisphenol has low reaction activity with the blocking agent methyl chloride, the product performance can be further improved by optimizing the reaction conditions, such as adopting the salt formation temperature and blocking time of the present invention.

[0055] In the present invention, there is no particular restriction on the amount of each reaction raw material. For example, taking bisphenol S and dichlorodiphenyl sulfone as reaction raw materials, the following raw material ratio is specifically adopted:

[0056] The molar ratio of bisphenol S to dichlorodiphenyl sulfone is 1:1.0 to 1:1.03;

[0057] The amount of the salt-forming agent added is 1.05 to 1.3 times the amount of the bisphenol S substance;

[0058] The amount of solvent added is such that the solid content of the reaction system reaches 20 to 55%, where the reaction system refers to a system consisting of bisphenol S and dichlorodiphenyl sulfone;

[0059] The amount of water-carrying agent added is 10-50% of the mass of the solvent or no water-carrying agent is added;

[0060] The amount of the end-capping agent added is 2-10% of the molar amount of bisphenol S.

[0061] The reaction conditions of the present invention are all carried out under a protective gas atmosphere such as nitrogen. The reaction container is baked, dried, dehydrated, and vacuumed and filled with nitrogen for multiple times.

[0062] Any steps not specifically described in the present invention may refer to the prior art, such as reactive liquid filtration, crushing, water washing, vacuum drying and the like, which may be implemented by conventional technical means in the art.

[0063] The present invention is further explained below by more specific examples, but does not constitute any limitation.

[0064] In the embodiments and comparative examples of the present invention, the sources of the main raw materials used are as follows. Unless otherwise specified, other raw materials and reagents were purchased from commercial sources:

[0065] Sodium carbonate: D50 is 180 μm, purchased from Shandong Haihua Group Co., Ltd., and ground to reduce the particle size D50 to 35 μm, 45 μm, 60 μm, 90 μm, 120 μm, etc., with a purity of 99%.

[0066] Potassium carbonate: purchased from Uni-President, purity 99%.

[0067] Bisphenol S: purchased from Nantong Botao Chemical Co., Ltd., purity 99.9%.

[0068] Bisphenol A: Produced by Wanhua Chemical, purity 99.9%.

[0069] 4,4′-Biphenyldiphenol: purchased from Honshu Chemical Industry Co., Ltd., purity 99.9%.

[0070] 4,4'-Dichlorodiphenyl sulfone: purchased from Jiangxi Jinhai New Energy Technology Co., Ltd., with a purity of 99.9%.

[0071] Sulfolane: purchased from Liaoning Guanghua Chemical Co., Ltd., purity 99.5%.

[0072] N-Methyl-2-pyrrolidone: produced by Wanhua Chemical, purity 99.9%.

[0073] The main test methods and test conditions used in the embodiments and comparative examples of the present invention are:

[0074] The molecular weight of the sulfone polymer was determined by gel permeation chromatography (GPC), with DMF containing 20 mmol lithium bromide as the mobile phase, PMMA as the standard sample, and Agilent MIXD C, MIXD D, and MIXD E columns connected in series at a flow rate of 1.0 mL / min.

[0075] The particle size analysis of sodium carbonate was carried out according to the particle size distribution laser diffraction method of GB / T 19077-2016, and anhydrous ethanol was used as the dispersant.

[0076] Yellowness: The yellowness index test standard is carried out in accordance with ASTM E313.

[0077] Example 1

[0078] To prepare sulfone polymer, sodium carbonate with a particle size D50 of 45 μm was selected as the salt-forming agent:

[0079] 1) Polymerization reaction: In a 150L reactor, 20022g (80mol) of bisphenol S, 22973g (80mol) of 4,4'-dichlorodiphenyl sulfone, and 9327g (88mol) of sodium carbonate were added to 19989g of cyclopentane sulfone in sequence, and then 3998g of xylene was added to the reactor. After heating to 180°C and reflux with water to form salt for 3h, the temperature was increased to completely evaporate the xylene in the reactor, followed by polymerization at 220°C for 3h.

[0080] 2) End-capping reaction: When the polymerization reaction reached the end point, the temperature was lowered to 180°C, and 202 g (4 mol) of methyl chloride was introduced for end-capping reaction for 1 hour.

[0081] 3) Post-treatment: After the end-capping reaction is completed, the product is washed, dried, and crushed to obtain a sulfone polymer product.

[0082] Performance test: The results show that the weight average molecular weight of the prepared sulfone polymer is 94285 g / mol, the molecular weight distribution is 1.69, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 15 ppm, and the yellowness index is 7.25.

[0083] Example 2

[0084] The difference from Example 1 is that sodium carbonate with a particle size D50 of 35 μm is selected as the salt-forming agent, 23662 g (82.4 mol) of 4,4'-dichlorodiphenyl sulfone, N-methylpyrrolidone is used as the solvent, the polymerization temperature is 200°C, the polymerization time is 6 h, the end-capping temperature is 160°C, the amount of the end-capping agent is 81 g (1.6 mol), the end-capping time is 2 h, and the other conditions remain unchanged.

[0085] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 94576 g / mol, the molecular weight distribution is 1.66, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 7 ppm, and the yellowness index is 6.57.

[0086] Example 3

[0087] The difference from Example 1 is that sodium carbonate with a particle size D50 of 90 μm is selected as the salt-forming agent, 23432 g (81.6 mol) of 4,4'-dichlorodiphenyl sulfone, N,N-dimethylacetamide is used as the solvent, the polymerization temperature is 160°C, the polymerization time is 48 h, the end-capping temperature is 160°C, the end-capping time is 0.5 h, and other conditions remain unchanged.

[0088] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 95083 g / mol, the molecular weight distribution is 1.68, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 24 ppm, and the yellowness index is 7.82.

[0089] Example 4

[0090] The difference from Example 1 is that: sodium carbonate with a particle size D50 of 60 μm is selected as the salt-forming agent, the amount of sodium carbonate is 10175 g (96 mol), the diphenol monomer is bisphenol A, the solvent is diphenyl sulfone, the polymerization temperature is 230°C, the polymerization time is 2h, the end-capping temperature is 170°C, the end-capping agent amount is 404 g (8 mol), the end-capping time is 1h, and other conditions remain unchanged.

[0091] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 86750 g / mol, the molecular weight distribution is 1.68, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 11 ppm, and the yellowness index is 6.74.

[0092] Example 5

[0093] The difference from Example 1 is that the diphenol monomer uses 4,4′-biphenyldiphenol, N-methylpyrrolidone is used as the solvent, the polymerization temperature is 190° C., the polymerization time is 4 h, the end-capping temperature is 165° C., the end-capping time is 1 h, and other conditions remain unchanged.

[0094] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 78545 g / mol, the molecular weight distribution is 1.61, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 8 ppm, and the yellowness index is 6.61.

[0095] Example 6

[0096] The difference from Example 1 is that sodium bicarbonate with a particle size D50 of 90 μm is selected as the salt-forming agent, the amount of sodium bicarbonate used is 7729 g (92 mol), and other conditions remain unchanged.

[0097] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 93540 g / mol, the molecular weight distribution is 1.69, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 10 ppm, and the yellowness index is 6.71.

[0098] Comparative Example 1

[0099] The difference from Example 1 is that sodium carbonate with a particle size D50 of 120 μm is selected as the salt-forming agent, and other conditions remain unchanged.

[0100] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 90280 g / mol, the molecular weight distribution is 1.83, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 40 ppm, and the yellowness index is 10.20.

[0101] Comparative Example 2

[0102] The difference from Example 2 is that sodium carbonate with a particle size D50 of 180 μm is selected as the salt-forming agent, and other conditions remain unchanged.

[0103] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 87650 g / mol, the molecular weight distribution is 1.87, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 50 ppm, and the yellowness index is 11.82.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that the salt-forming agent is replaced by an equal amount of potassium carbonate with a particle size D50 of 45 μm, and other conditions remain unchanged.

[0106] Performance evaluation: The results show that the weight average molecular weight of the prepared sulfone polymer is 95208 g / mol, the molecular weight distribution is 1.79, the content of 4-chloro-4'-hydroxydiphenyl sulfone is 68 ppm, and the yellowness index is 13.56.

Claims

1. A method for preparing a sulfone polymer, characterized in that: The following steps are involved: S1: adding diphenol monomer, disulfone monomer and salt-forming agent into a solvent, then heating under reflux to perform salt-forming reaction, and then performing polymerization reaction; S2: adding a capping agent to the S2 system to carry out a capping reaction to obtain a sulfone polymer; Wherein, the salt-forming agent in step S1 is sodium carbonate and / or sodium bicarbonate, and the particle size D50 is ≤100 μm.

2. The preparation method according to claim 1, characterized in that: The diphenol monomer in step S1 is selected from one or more of bisphenol A, bisphenol S, and 4,4′-biphenol; and / or The disulfone monomer in step S1 is selected from one or more of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone, preferably 4,4'-dichlorodiphenyl sulfone; and / or The molar ratio of the diphenol monomer to the disulfone monomer in step S1 is 1:1.0-1.

03.

3. The preparation method according to claim 1 or 2, characterized in that: The particle size D50 of the salt-forming agent in step S1 is ≤ 80 μm; and / or The salt-forming agent in step S1 is sodium carbonate; and / or The amount of the salt-forming agent added in step S1 is 1.05 to 1.3 times the molar amount of the diphenol monomer.

4. The preparation method according to any one of claims 1 to 3, characterized in that The solvent in step S1 is selected from one or more of sulfolane, diphenyl sulfone, N,N-dimethylacetamide, and N-methylpyrrolidone, preferably one or more of sulfolane, N-methylpyrrolidone, and N,N-dimethylacetamide; and / or In step S1, based on the total mass of the diphenol monomer and the disulfone monomer, the mass proportion of the solvent is 45-80%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In the salt-forming reaction of step S1, the reflux reaction temperature is 140-220° C. and the reflux reaction time is 2-6 h; and / or The polymerization reaction in step S1 is carried out at a temperature of 160 to 230° C. and for a time of 2 to 48 hours.

6. The preparation method according to any one of claims 1 to 5, characterized in that: Step S1: adding a water-carrying agent during the salt-forming reaction by heating under reflux; Preferably, the water-carrying agent is selected from one or more of toluene, xylene, o-xylene, chlorobenzene, and mesitylene, more preferably toluene and xylene; Preferably, the amount of the water-carrying agent added is 10-50% of the mass of the solvent.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The end-capping agent in step S2 is selected from one or more of methyl chloride, chloromethyl methyl ether, 4-fluorobenzophenone, and 3,4-difluorobenzophenone, preferably methyl chloride; and / or The amount of the end-capping agent added in step S2 is 2-10% of the molar amount of the diphenol monomer in step S1.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The end-capping reaction in step S2 is carried out at a temperature of 160 to 180° C. for 0.5 to 2 h; and / or The reactions in step S1 and step S2 are both carried out in a protective gas environment, preferably a nitrogen environment.

9. A sulfone polymer prepared by the preparation method according to any one of claims 1 to 8.

10. The sulfone polymer according to claim 9, characterized in that The molecular weight distribution of the sulfone polymer is ≤2.0, preferably 1.5 to 1.9; and / or The sulfone polymer has a weight average molecular weight of 50,000 to 150,000 g / mol, preferably 60,000 to 100,000 g / mol; and / or The content of 4-chloro-4'-hydroxydiphenyl sulfone impurity in the sulfone polymer is less than 30 ppm, and the yellowness index of the product is ≤8.