A sulfone-based polymer and a method for preparing the same

Abstract

The present application relates to a kind of sulfone polymer and its preparation method, which includes the following steps: S1: under the action of reflux, organic bisphenol compound and salt-forming agent are subjected to salt-forming reaction;S2: 4,4'-dichlorodiphenyl sulfone is added to the system after the salt-forming reaction is completed to carry out polymerization reaction;Wherein, the salt-forming reaction system of step S1 includes the organic bisphenol compound, the salt-forming agent, solvent N-methylpyrrolidone and 4,4'-dichlorodiphenyl sulfone.The preparation method of sulfone polymer of an embodiment of the present application can reduce the occurrence of side reactions caused by solvent N-methylpyrrolidone by adding 4,4'-dichlorodiphenyl sulfone into the reaction system in batches, and sulfone polymer with narrow molecular weight distribution and high thermal stability is prepared.

Description

Technical Field

[0001] This invention relates to sulfone polymers, and more particularly to a sulfone polymer with high thermal stability. Background Technology

[0002] Sulfone polymers are important thermoplastic specialty engineering plastics, mainly including polyethersulfone (PES), bisphenol A polysulfone (PSU), and polyphenylene sulfone (PPSU). Sulfone polymer resins possess excellent properties, such as superior mechanical properties, high-temperature resistance, chemical corrosion resistance, and aging resistance. These characteristics make these materials widely used in numerous fields, including electronics, electrical engineering, medical applications, nuclear power, oil wells, shipbuilding, magnetic materials, automotive manufacturing, and food processing.

[0003] Sulfonate polymers are generally prepared by reacting bisphenol compounds, 4,4'-dichlorodiphenyl sulfone, and alkali / alkali metal salts in an aprotic solvent. Commonly used aprotic polar solvents include N-methylpyrrolidone (NMP), N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and sulfolane. Among these, NMP has a high boiling point, strong thermal stability, and is easily removed in post-processing, making it a frequently used polymerization solvent for sulfonate polymers.

[0004] However, in existing methods for preparing the aforementioned sulfone polymers, the solvent NMP participates in the reaction, resulting in polymers containing NMP end groups. This side reaction not only leads to an imbalance in the monomer ratio and a decrease in the polymerization rate, but also results in lower thermal stability of the molecular chains containing NMP end groups. These chains are prone to decomposition during subsequent extrusion granulation and injection molding, leading to a decline in the product's appearance. Furthermore, the generated nitrogen-containing small molecules have a pungent odor, limiting the development of the material in high-end applications. Summary of the Invention

[0005] To overcome at least one of the defects of the prior art, in a first aspect, one embodiment of the present invention provides a method for preparing a sulfone polymer, comprising the following steps:

[0006] S1: Under reflux, the organic bisphenol compounds and the salt-forming agent undergo a salt-forming reaction;

[0007] S2: Add 4,4'-dichlorodiphenyl sulfone to the system after the salt formation reaction is completed to carry out a polymerization reaction;

[0008] The salt-forming reaction system in step S1 includes the organic bisphenol compound, the salt-forming agent, the solvent N-methylpyrrolidone, and 4,4'-dichlorodiphenyl sulfone.

[0009] Secondly, one embodiment of the present invention provides a sulfone polymer, which is prepared by the above-described preparation method.

[0010] The present invention discloses a method for preparing sulfone polymers by adding 4,4'-dichlorodiphenyl sulfone to the reaction system in batches, which can reduce the occurrence of side reactions caused by the solvent N-methylpyrrolidone and obtain sulfone polymers with narrow molecular weight distribution and high thermal stability. Detailed Implementation

[0011] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the description herein is for illustrative purposes only and not intended to limit the present invention.

[0012] One embodiment of the present invention provides a method for preparing a sulfone polymer, comprising the following steps:

[0013] S1: Under reflux, the organic bisphenol compounds and the salt-forming agent undergo a salt-forming reaction;

[0014] S2: Add 4,4'-dichlorodiphenyl sulfone to the system after the salt formation reaction is completed to carry out the polymerization reaction;

[0015] The salt-forming reaction system in step S1 includes an organic bisphenol compound, a salt-forming agent, a solvent N-methylpyrrolidone, and 4,4'-dichlorodiphenyl sulfone.

[0016] In one embodiment, the molar ratio of 4,4'-dichlorodiphenyl sulfone contained in the salt-forming reaction system of step S1 to the 4,4'-dichlorodiphenyl sulfone added in step S2 can be (5-7):(3-5), or more preferably (5-6):(4-5), for example 5:5, 52:48, 55:45, 58:42, 6:4, 62:38, 65:35, 68:32 or 7:3.

[0017] In one embodiment, step S1 includes: subjecting an organic bisphenol compound and a salting agent to a salting reaction for 1 to 3 hours (e.g., 1.5 hours, 2 hours, 2.5 hours), then adding 4,4'-dichlorodiphenyl sulfone to the system, and then reacting for another 1 to 3 hours (e.g., 1.5 hours, 2 hours, 2.5 hours).

[0018] In one embodiment, in step S1, a mixture of organic bisphenol compound, salting agent, and N-methylpyrrolidone is subjected to a salting reaction for 1 to 3 hours, followed by the addition of a solution of 4,4'-dichlorodiphenyl sulfone in N-methylpyrrolidone to the system, and then the reaction is carried out for another 1 to 3 hours; in the mixture, the molar ratio of organic bisphenol compound to N-methylpyrrolidone is 1:20 to 1:50, and more preferably 1:30 to 1:40, for example 1:25, 1:32, 1:35, 1:38, or 1:45.

[0019] In one embodiment, in the N-methylpyrrolidone solution of 4,4'-dichlorodiphenyl sulfone, the molar ratio of 4,4'-dichlorodiphenyl sulfone to N-methylpyrrolidone is 1:5 to 1:10, for example 1:6, 1:7, 1:8, or 1:9.

[0020] In one embodiment, the molar ratio of the organic bisphenol compound to the salt-forming agent is 1:1 to 1:1.5, and more preferably 1:1 to 1:1.3, such as 1:1.1, 1:1.2, or 1:1.4.

[0021] In one embodiment, the molar amount of 4,4'-dichlorodiphenyl sulfone contained in the salt-forming reaction system of step S1 is 50-70% of the molar amount of the organic bisphenol compound, more specifically 50-60%, for example 55%, 58%, 60%, 62%, 65%, or 68%.

[0022] In one embodiment, the molar amount of 4,4'-dichlorodiphenyl sulfone added in step S2 is 30-50% of the molar amount of the organic bisphenol compound, more specifically 40-50%, for example 35%, 38%, 40%, 42%, 45%, or 48%.

[0023] In one embodiment, the number of moles of organic bisphenol compounds used in the preparation method of sulfone polymers (i.e., the number of moles of organic bisphenol compounds added in step S1) is equal to the total number of moles of 4,4'-dichlorodiphenyl sulfones used (i.e., the sum of the number of moles of 4,4'-dichlorodiphenyl sulfones added in steps S1 and S2).

[0024] In one embodiment, the organic bisphenol compound includes one or more of bisphenol A, bisphenol F, dihydroxydiphenyl sulfone, hydroquinone, resorcinol, dihydroxybenzophenone, dihydroxydiphenyl ether, 4,4′-biphenyl, hexafluorobisphenol A, tetrabromobisphenol A, and dihydroxynaphthalene.

[0025] In one embodiment, the salt-forming agent includes one or more of potassium salt, sodium salt, sodium hydroxide, and potassium hydroxide; further, the salt-forming agent includes one or more of potassium carbonate, sodium carbonate, sodium hydroxide, and potassium hydroxide.

[0026] In one embodiment, the reaction temperature of step S1 can be 180-200°C, for example 185°C, 190°C, or 195°C; the reaction time of step S1 can be 2-10 hours, and more specifically 3-5 hours, for example 4 hours, 6 hours, or 8 hours.

[0027] In one embodiment, the reaction temperature of step S2 can be 180-200°C, for example 185°C, 190°C, or 195°C; the reaction time of step S2 can be 2-10 hours, for example 4 hours, 6 hours, or 8 hours.

[0028] In one embodiment, a solution of 4,4'-dichlorodiphenyl sulfone in N-methylpyrrolidone (NMP solution) is prepared, and the NMP solution is divided into two parts, the first part of the solution accounting for 50-70% of the total mass of the NMP solution, and the remaining second part of the solution accounting for 30-50% of the total mass of the NMP solution; in step S1, the first part of the solution is added to the salt formation reaction system, and in step S2, the second part of the solution is added.

[0029] One embodiment of the present invention provides a sulfone polymer, which is prepared by the above-described preparation method.

[0030] In one embodiment, the molecular weight distribution of the sulfone polymer is 1.4 to 1.7, for example 1.5 or 1.6.

[0031] In one embodiment, the weight-average molecular weight of the sulfone polymer is 60,000 to 11,000, for example 65,000, 68,000, 69,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, 100,000, and 105,000.

[0032] In one embodiment, the content of the polymer with structure I below in the sulfone polymer is less than 3 mol%.

[0033]

[0034] Where X represents the structure of an organic bisphenol compound; the polymer of structure I is the product of a side reaction involving the solvent N-methylpyrrolidone.

[0035] In one embodiment, the polymer of structure I is present in the sulfone polymer at a concentration of 0.5–1.1 mol%, for example, 0.6 mol%, 0.8 mol%, or 1.0 mol%.

[0036] The sulfone polymer prepared according to one embodiment of the present invention has the characteristics of high thermal stability and low odor.

[0037] The present invention discloses a method for preparing sulfone polymers by adding 4,4'-dichlorodiphenyl sulfone to the reaction system in batches, which can reduce the occurrence of side reactions caused by the solvent N-methylpyrrolidone and obtain sulfone polymers with narrow molecular weight distribution and high thermal stability.

[0038] The method for preparing sulfone polymers according to one embodiment of the present invention controls the addition of 4,4'-dichlorodiphenyl sulfone during the salt formation process, thereby reducing the occurrence of side reactions caused by the solvent N-methylpyrrolidone, increasing the reaction rate of the main reaction, and resulting in sulfone polymers with narrow molecular weight distribution, high thermal stability, excellent optical properties after extrusion processing, and low odor.

[0039] The preparation method of the sulfone polymer according to one embodiment of the present invention will be further described below with reference to the embodiments. The test methods involved in each embodiment and comparative example are as follows.

[0040] 1. Weight-average molecular weight and molecular weight distribution

[0041] Weight-average molecular weight M w The molecular weight distribution was determined by gel permeation chromatography (GPC).

[0042] 2. Content of Structure I

[0043] The content of structure I was determined by 1H NMR spectroscopy (NMR spectroscopy). 1 Measured by H-NMR.

[0044] 3. Thermogravimetric temperature

[0045] The 5% thermogravimetric temperature was measured using a thermogravimetric analyzer (TGA).

[0046] 4. Odor rating

[0047] Odor ratings are tested according to VW50180 standard requirements.

[0048] Example 1

[0049] S1: Place a four-necked flask equipped with a water separator, condenser, and mechanical stirrer in an oil bath reactor. Add 0.25 mol of bisphenol A, 0.375 mol of potassium carbonate, and 12.5 mol of N-methylpyrrolidone to the flask in sequence. Raise the reaction temperature to 200°C and reflux under normal pressure for 1 hour to remove water. Then, add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.175 mol of 4,4'-dichlorodiphenyl sulfone) to the system, maintain the reaction temperature at 200°C, and continue to remove water for 1 hour.

[0050] S2: Add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.075 mol of 4,4'-dichlorodiphenyl sulfone) to the system of step S1, maintain the reaction temperature at 200℃, and react at atmospheric pressure for 2 hours to obtain a viscous polymer solution.

[0051] Example 2

[0052] S1: Place a four-necked flask equipped with a water separator, condenser, and mechanical stirrer in an oil bath reactor. Add 0.1 mol of bisphenol A, 0.1 mol of sodium carbonate, and 2 mol of N-methylpyrrolidone to the flask in sequence. Raise the reaction temperature to 180°C and reflux under normal pressure for 3 hours to remove water. Then, add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.05 mol of 4,4'-dichlorodiphenyl sulfone) to the system, maintain the reaction temperature at 180°C, and continue to remove water for 3 hours.

[0053] S2: Add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.05 mol of 4,4'-dichlorodiphenyl sulfone) to the system of step S1. The reaction temperature is 180℃ and the reaction is carried out at atmospheric pressure for 10 h to obtain a viscous polymer solution.

[0054] Example 3

[0055] S1: Add 1 mol of bisphenol A, 1.2 mol of potassium carbonate, and 35 mol of N-methylpyrrolidone to a reactor equipped with a temperature control, stirring, and reflux water separation device at once. Raise the reaction temperature to 190°C and reflux under normal pressure for 2 hours to remove water. Then, add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.6 mol of 4,4'-dichlorodiphenyl sulfone) to the system, maintain the reaction temperature at 190°C, and continue to remove water for 2 hours.

[0056] S2: Add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 0.4 mol of 4,4'-dichlorodiphenyl sulfone) to the system of step S1, maintain the reaction temperature at 190℃, and react at atmospheric pressure for 6 h to obtain a viscous polymer solution.

[0057] Example 4

[0058] S1: Add 4 mol of 4,4'-biphenylhydroquinone, 4 mol of sodium carbonate, and 80 mol of N-methylpyrrolidone to a reactor equipped with a temperature control, stirring, and reflux water separation device at once. Raise the reaction temperature to 180°C and reflux under normal pressure for 3 hours to remove water. Then, add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 2 mol of 4,4'-dichlorodiphenyl sulfone) to the system, maintain the reaction temperature at 180°C, and continue to remove water for 3 hours.

[0059] S2: Add a 4,4'-dichlorodiphenyl sulfone / NMP solution (containing 2 mol of 4,4'-dichlorodiphenyl sulfone) to the system of step S1, maintain the reaction temperature at 200℃, and react at atmospheric pressure for 2 hours to obtain a viscous polymer solution.

[0060] Comparative Example 1

[0061] A four-necked flask equipped with a water separator, condenser, and mechanical stirrer was placed in an oil bath reactor. 0.25 mol of bisphenol A, 0.375 mol of potassium carbonate, 0.25 mol of 4,4'-dichlorodiphenyl sulfone, and 12.5 mol of N-methylpyrrolidone were added to the flask in sequence. The reaction temperature was directly raised to 200 °C, and the mixture was refluxed to remove water for 2 hours. The reaction was continued for another 2 hours to obtain a viscous polymer solution.

[0062] Comparative Example 2

[0063] A four-necked flask equipped with a water separator, condenser, and mechanical stirrer was placed in an oil bath reactor. 0.25 mol of bisphenol A, 0.25 mol of sodium carbonate, 0.25 mol of 4,4'-dichlorodiphenyl sulfone, and 5 mol of N-methylpyrrolidone were added to the flask in sequence. The reaction temperature was raised to 180 °C, and the mixture was refluxed to remove water for 6 hours. The reaction was continued for 10 hours to obtain a viscous polymer solution.

[0064] The sulfone polymers prepared in each embodiment and comparative example were tested according to the aforementioned method, and the results are shown in Table 1.

[0065] Table 1

[0066]

[0067] As can be seen from the data in Table 1, in Examples 1 to 4 of this invention, 4,4'-dichlorodiphenyl sulfone was added to the reaction system in two separate steps. The resulting sulfone polymers had high molecular weight, narrow molecular weight distribution, and high thermal stability. Due to the occurrence of side reactions, fewer structures were introduced, and the product performance was greatly improved.

[0068] In Comparative Examples 1 and 2, 4,4'-dichlorodiphenyl sulfone was directly added to the reaction system in a single step. The molecular weight and molecular weight distribution of the resulting sulfone polymers were lower than those of the polymers in Examples 1 to 4. Furthermore, the content of byproduct structure I in the sulfone polymers of Comparative Examples 1 and 2 was significantly higher than that in Examples 1 to 4, and their thermal decomposition temperatures were also lower. Additionally, their odor levels were also higher. Therefore, the quality of the sulfone polymers obtained in Comparative Examples 1 and 2 was significantly lower than that of the polymers in Examples 1 to 4.

[0069] Unless otherwise specified, the terms used in this invention have the meanings commonly understood by those skilled in the art.

[0070] The embodiments described in this invention are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. A method for preparing a sulfone polymer, comprising the following steps: S1: Under reflux, a mixture of organic bisphenol compounds, salting agent and N-methylpyrrolidone is subjected to a salting reaction for 1 to 3 hours. Then, a solution of N-methylpyrrolidone in 4,4'-dichlorodiphenyl sulfone is added to the system, and the reaction is carried out for another 1 to 3 hours. S2: Add 4,4'-dichlorodiphenyl sulfone to the system after the salt formation reaction is completed to carry out a polymerization reaction; in, The molar ratio of 4,4'-dichlorodiphenyl sulfone contained in the salt-forming reaction system of step S1 to that added in step S2 is (5-7):(3-5); the reaction temperature of step S1 is 180-200℃, and the reaction temperature of step S2 is 180-200℃.

2. The preparation method according to claim 1, wherein, In the mixture, the molar ratio of the organic bisphenol compound to the N-methylpyrrolidone is 1:20 to 1:50; in the N-methylpyrrolidone solution of 4,4'-dichlorodiphenyl sulfone, the molar ratio of the 4,4'-dichlorodiphenyl sulfone to the N-methylpyrrolidone is 1:5 to 1:

10.

3. The preparation method according to claim 1, wherein, The reaction time for step S2 is 2 to 10 hours.

4. The preparation method according to claim 1, wherein, The organic bisphenol compounds include one or more of bisphenol A, bisphenol F, dihydroxydiphenyl sulfone, hydroquinone, resorcinol, dihydroxybenzophenone, dihydroxydiphenyl ether, 4,4′-biphenyl, hexafluorobisphenol A, tetrabromobisphenol A, and dihydroxynaphthalene; and / or, The salt-forming agent includes one or more of potassium salts, sodium salts, sodium hydroxide, and potassium hydroxide.

5. The preparation method according to claim 4, wherein, The salt-forming agent includes one or more of potassium carbonate, sodium carbonate, sodium hydroxide, and potassium hydroxide.

6. The preparation method according to claim 1, wherein, The molar ratio of the organic bisphenol compound to the salt-forming agent is 1:1 to 1:1.5; and / or, The molar number of 4,4'-dichlorodiphenyl sulfone contained in the salt-forming reaction system of step S1 is 50 to 70% of the molar number of the organic bisphenol compound.

7. The preparation method according to claim 1, wherein, The molar ratio of the organic bisphenol compound to the salt-forming agent is 1:1 to 1:1.3; and / or, The molar amount of 4,4'-dichlorodiphenyl sulfone added in step S2 is 30-50% of the molar amount of the organic bisphenol compound; and / or, In the mixture of step S1, the molar ratio of the organic bisphenol compound to the N-methylpyrrolidone is 1:30 to 1:

40.

8. A sulfone polymer, prepared by any one of claims 1 to 7.

9. The sulfone polymer according to claim 8, wherein the molecular weight distribution is 1.4 to 1.7.

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