A sulfone polymer and preparation method thereof

Abstract

The invention discloses a sulfone polymer and a preparation method thereof, and belongs to the technical field of polymer material preparation. In the preparation method of the sulfone polymer provided by the invention, a nucleating agent with a specific particle size range is added at a suitable rate at a specific reaction stage in the reaction process of preparing the sulfone polymer, and the Na salt generated by the reaction adheres to the surface of the nucleating agent, so that the particle size of the byproduct salt generated by the reaction is increased, the proportion of the Na salt dispersed in the polymerization reaction system is reduced, the nucleophilic substitution reaction proceeds in a positive direction, the polymerization reaction is more complete, the thermal stability of the resin is improved, and the color is lighter.

Description

Technical Field

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

[0002] Sulfone polymers are a class of high-performance amorphous thermoplastic engineering plastics containing characteristic diaryl sulfone chain segments. They are widely used due to their excellent properties such as high mechanical strength, heat resistance, oxidation resistance, hydrolysis resistance, and acid and alkali resistance.

[0003] Sulfone polymer is a slightly amber non-crystalline transparent or translucent high molecular polymer, and is an amorphous, thermoplastic resin. Researchers in this field have found that insufficient polymerization reaction will lead to poor thermal stability of the final product, easy decomposition, and dark product color. To prepare light-colored resins, it is necessary to improve the thermal stability of the resin. According to the currently disclosed formula and process for preparing sulfone polymers, the salt particle size generated during the polymerization reaction is relatively fine, usually 0.1-100μm, D90<50μm, and the generated salt is dispersed in the solution system to form a suspension, which affects the reaction and ultimately leads to insufficient polymerization reaction and dark resin color.

[0004] There are many reports on methods for improving the thermal stability of resins. For example, CN109734913A cools the reaction after completion and adds methyl bromide to cap the reaction, so that a specific content of ortho-etheroxy substituent isomers exists on the benzene ring structure, thereby improving the thermal stability of the resin. However, the additive is highly dangerous and harmful to the human body. CN115058008A adds p-hydroxyaniline to the reaction system, introduces a biphenyl structure into the obtained polysulfone polymer, thereby improving the thermal stability. p-hydroxyaniline is a potential carcinogen, and the residual amount of p-hydroxyaniline in the product limits the application of polysulfone products in some specific fields.

[0005] Therefore, it is urgent to develop a new method for synthesizing sulfone polymers, improve the sufficiency of the polymerization reaction, improve the thermal stability of the resin, and prepare a method for light-colored resin. Summary of the invention

[0006] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a method for increasing the particle size of by-product salt from the source, i.e., from the polymerization process, by introducing a nucleating agent at a specific polymerization stage, so that the proportion of Na salt dispersed in the polymerization system is reduced, the nucleophilic substitution reaction proceeds in a positive direction, the reaction is more complete, the thermal stability of the resin is improved, and the color is lighter. Since the particle size of the sodium salt increases during the reaction, the proportion of the sodium salt dispersed in the solution per unit volume is reduced, so that the monomer dichloride and the intermediate phenol sodium salt are more fully contacted during the polymerization process, the nucleophilic substitution reaction is promoted to proceed in a positive direction, and the polymerization reaction is more complete.

[0007] To achieve the above object, in a first aspect of the present invention, the present invention provides a sulfone polymer, wherein the shear viscosity change rate of the sulfone polymer is -0.52% to -0.88%, and the b value is 9.16-11.89.

[0008] In a second aspect of the present invention, the present invention provides a method for preparing a sulfone polymer, the preparation method comprising the following steps:

[0009] Phenol monomer, sulfone monomer, salt-forming agent, solvent and dehydrating agent are mixed and reacted at elevated temperature. When the temperature of the reaction system is 160-220° C., a nucleating agent with an average particle size of 0.05-2.0 mm is added at a rate of 1-10 g / min. After the addition, the viscosity of the reaction system is ≤300 cps.

[0010] After the reaction is continued until the target viscosity is reached, the solvent is added, mixed with water and precipitated, and then the precipitate is collected, crushed, washed and dried to obtain a sulfone polymer;

[0011] The nucleating agent is a chloride salt soluble in water.

[0012] In the preparation method of the sulfone polymer provided by the present invention, a nucleating agent with a specific particle size range is added at a suitable rate at a specific reaction stage in the reaction process of preparing the sulfone polymer, so that the particle size of the byproduct salt generated by the reaction can be increased, and the proportion of the Na salt dispersed in the polymerization reaction system can be reduced, so that the monomer dichloride and the intermediate phenol sodium salt can be more fully contacted during the polymerization reaction, the nucleophilic substitution reaction is promoted to proceed in the forward direction, the polymerization reaction is more complete, the thermal stability of the resin is improved, and the color is lighter.

[0013] The test method for the viscosity of the reaction system is based on ISO 1628-3-2010.

[0014] The shear viscosity test method is tested according to ASTM D3835-2016.

[0015] The test method for the average particle size of the nucleating agent is to refer to GB / T 13025.1-2012 for testing.

[0016] The reaction is continued until the target viscosity is set according to the target sulfone polymer, and the target viscosity is between 100-3000 cps, for example, for polysulfone, the target viscosity is 150-700 cps, for polyphenylsulfone, the target viscosity is 300-1200 cps, and for polyethersulfone, the target viscosity is 200-900 cps.

[0017] As a preferred embodiment of the preparation method of the present invention, the nucleating agent is added when the reaction temperature is 165-180° C., and after the addition, the viscosity of the reaction system is 100-260 cps.

[0018] The inventors have found that the timing of adding the nucleating agent significantly affects the particle size of the by-product salt formed. By limiting the addition within a specific reaction temperature range and controlling the viscosity after the addition within a certain range, it can be ensured that the added nucleating agent can attract the aggregation of the by-product salt, thereby increasing the particle size of the by-product salt; if the addition time is too early or too late, there is no way to increase the particle size of the by-product salt. When the nucleating agent is further added at a reaction temperature of 165-180°C, when the viscosity of the reaction system is 150-260cps after the addition, the particle size of the by-product salt is larger, and the comprehensive performance of the sulfone polymer is more excellent.

[0019] As a preferred embodiment of the preparation method of the present invention, the addition rate of the nucleating agent is 3-8 g / min.

[0020] The addition rate of the nucleating agent will not only affect the dispersion state of the nucleating agent in the reaction system, but also because the salt-forming reaction is ongoing during the addition of the nucleating agent, that is, the sodium phenolate is being generated, the addition rate will also affect the adhesion state and adhesion rate of the sodium phenolate on the surface of the nucleating agent; the inventors have found that when the addition rate is controlled to be 1-10g / min, especially 3-8g / min, the salt particle size generated during the reaction is larger and the shear viscosity change rate of the resin is lower.

[0021] As a preferred embodiment of the preparation method of the present invention, the average particle size of the nucleating agent is 0.03-2.2 mm.

[0022] Preferably, the average particle size of the nucleating agent is 0.05-2.0 mm; more preferably, the average particle size of the nucleating agent is 1-1.5 mm. Exemplarily, the average particle size of the nucleating agent can be any point value in 1-1.5 mm or a range value consisting of any two points, such as 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc. Within the range of 1-1.5 mm given in the present invention, more excellent technical effects can be achieved.

[0023] The average particle size of the nucleating agent will significantly affect the comprehensive properties of the prepared sulfone polymer. When the average particle size of the nucleating agent is selected to be 0.03-2.2 mm, especially 1-1.5 mm, the by-product salts generated during the reaction can be better enriched, thereby increasing the particle size of the by-product salts, reducing the proportion of sodium salts in the solution system, promoting the nucleophilic substitution reaction to proceed in the forward direction, and making the polymerization reaction more complete, thereby obtaining a sulfone polymer with excellent comprehensive properties.

[0024] As a preferred embodiment of the preparation method of the present invention, the nucleating agent is at least one of sodium chloride, potassium chloride, calcium chloride and zinc chloride.

[0025] Preferably, the nucleating agent is sodium chloride or potassium chloride.

[0026] On the one hand, sodium carbonate or potassium carbonate is conventionally used as the salt-forming agent in the sulfone polymer reaction, and the corresponding by-product salt is sodium chloride or potassium chloride; on the other hand, it is verified by experiments that the introduced chlorine atoms will not damage the performance of the product; therefore, the auxiliary agent is preferably sodium chloride or potassium chloride, which can better make the by-product salt form large particles, and the comprehensive performance of the obtained sulfone polymer is excellent.

[0027] As a preferred embodiment of the preparation method of the present invention, the amount of the nucleating agent added is 0.01-0.1% based on the total moles of the phenolic monomer and the sulfone monomer.

[0028] The inventors have found that when the amount of the nucleating agent added is selected within the above range, a more excellent effect can be achieved. If the nucleating agent is further increased or decreased, the performance of the product will be damaged to a certain extent.

[0029] As a preferred embodiment of the preparation method of the present invention, stirring is maintained when the nucleating agent is added, and the stirring speed is 200-700 r / min.

[0030] As a preferred embodiment of the preparation method of the present invention, the sulfone polymer is polysulfone, polyphenylsulfone or polyethersulfone.

[0031] Depending on the target sulfone polymer, the phenol monomers and sulfone monomers used are also different; however, the present invention uses conventional phenol monomers and sulfone monomers; the solvent, dehydrating agent, and salt-forming agent used are also substances conventionally used in the art; for example, the solvent may be dimethyl sulfoxide, cyclopentane, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; for example, the dehydrating agent may be xylene; the salt-forming agent may be sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium bicarbonate or potassium bicarbonate; for example, the phenol monomer used may be at least one of 4,4'-dihydroxydiphenyl sulfone, biphenyl diphenol, and 2,2'-bis(4-hydroxyphenyl)propane, and the sulfone monomer may be at least one of 4,4'-dichlorodiphenyl sulfone, 4,4'-difluorodiphenyl sulfone, and bis-(4-chlorophenylsulfone)biphenyl.

[0032] When a phenol monomer, a sulfone monomer, a salt-forming agent, a solvent and a dehydrating agent are mixed for a temperature reaction, the temperature rising process is controlled according to a program. For different target sulfone polymers, the temperature rising rate is also different. For example, for polysulfone, the temperature rising program is room temperature - 195°C, and the temperature rising rate is 0.3-6°C / min. For polyphenylsulfone, the temperature rising program is room temperature - 240°C, and the temperature rising rate is 0.3-6°C / min. For polyethersulfone, the temperature rising program is room temperature - 240°C, and the temperature rising rate is 0.3-6°C / min.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the preparation method of the sulfone polymer provided by the present invention, a nucleating agent with a specific particle size range is added at a suitable rate at a specific reaction stage in the reaction process of preparing the sulfone polymer, so that the particle size of the byproduct salt generated by the reaction can be increased, and the proportion of the Na salt dispersed in the polymerization reaction system can be reduced, so that the monomer dichloride and the intermediate phenol sodium salt can be more fully contacted during the polymerization reaction, the nucleophilic substitution reaction is promoted to proceed in the forward direction, the polymerization reaction is more complete, the thermal stability of the resin is improved, and the color is lighter. Specifically, the shear viscosity change rate of the obtained sulfone polymer is -0.52% to -0.88%, and the b value is 9.16-11.89. DETAILED DESCRIPTION

[0035] 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.

[0036] Unless otherwise specified, the reagents, methods and equipment used in the present invention are all conventional reagents, methods and equipment in the art; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch of raw materials.

[0037] Example 1

[0038] An embodiment of the present invention provides a sulfone polymer, and a method for preparing the sulfone polymer comprises the following steps:

[0039] 43 kg of sulfolane, 8.76 kg of 4,4'-dichlorodiphenyl sulfone and 5.63 kg of 4,4'-biphenyl diphenol, 3.8 kg of sodium carbonate and 3.5 kg of xylene were quantitatively added to a 100 L reactor, the reactor was evacuated, nitrogen was introduced for replacement three times, and the temperature was increased under nitrogen protection. The temperature increase process was carried out according to the set program. The specific heating rate was room temperature -240°C and the heating rate was 2°C / min. When the temperature of the material in the reactor reached 165°C, the stirring speed was increased to 300 r / min. Under nitrogen protection, sodium chloride with an average particle size of 1 mm was added to the reactor at a rate of 3 g / min. The molar number of sodium chloride was 0.05% of the total molar number of phenolic monomers and sulfone monomers. After the addition, the viscosity of the material in the reactor was 260 cps. The reaction continued until the target viscosity of 785 cps was reached;

[0040] Then, a solvent accounting for 40% of the volume of the reaction solution is added to the reaction system and stirred evenly. The solution is solidified and precipitated in a precipitation bath. After washing with water and drying, a polyphenylsulfone resin is obtained.

[0041] Embodiment 2-10

[0042] Examples 2-10 of the present invention explore the effects of the type, average particle size, addition amount and addition speed of the nucleating agent. Except for the different parameters listed in Table 1, the other parameters of Examples 2-10 of the present invention are consistent with Example 1; wherein the addition amount refers to the mass percentage of the mole number of sodium chloride to the total mole number of phenolic monomers and sulfone monomers;

[0043] Table 1

[0044]

[0045] Embodiment 11

[0046] An embodiment of the present invention provides a sulfone polymer, and a method for preparing the sulfone polymer comprises the following steps:

[0047] In a 100L reactor, 45kg of dimethyl sulfoxide and 9.1kg of 4,4'-dichlorodiphenyl sulfone and 6.55kg bisphenol A, 3.6kg sodium carbonate and 3.5kg xylene, vacuum the kettle, introduce nitrogen for replacement three times, heat up under nitrogen protection, and the heating process is carried out according to the set program. The specific heating program is room temperature -195℃, and the heating rate is 2℃ / min. When the temperature of the material in the reactor reaches 165℃, the stirring speed is increased to 300r / min. Under nitrogen protection, sodium chloride with an average particle size of 1mm is added to the reactor at a speed of 3g / min. The mole number of sodium chloride is 0.05% of the total mole of phenol monomers and sulfone monomers. After the addition, the viscosity of the material in the kettle is 163cps. The reaction continues until the target viscosity of 368cps is reached; then, a solvent of 40% of the volume of the reaction solution is added to the reaction system and stirred evenly. The solution is solidified and precipitated in a precipitation bath. After washing and drying, a polysulfone resin is obtained.

[0048] Example 12

[0049] An embodiment of the present invention provides a sulfone polymer, and a method for preparing the sulfone polymer comprises the following steps:

[0050] 45 kg of sulfolane, 9.8 kg of 4,4'-dichlorodiphenyl sulfone and 7.3 kg of 4,4'-dihydroxydiphenyl sulfone, 2.45kg sodium carbonate and 3.5kg xylene, vacuum the kettle, introduce nitrogen for replacement three times, heat up under nitrogen protection, and the heating process is carried out according to the set program. The specific heating program is room temperature -240℃, and the heating rate is 2℃ / min. When the material temperature in the reactor reaches 165℃, the stirring speed is increased to 300r / min. Under nitrogen protection, sodium chloride with an average particle size of 1mm is added to the reactor at a rate of 3g / min. The mole number of sodium chloride is 0.05% of the total mole of phenolic monomers and sulfone monomers. After the addition, the viscosity of the material in the kettle is 181cps. The reaction continues until the target viscosity of 412cps is reached; then 40% of the volume of the reaction solution solvent is added to the reaction system and stirred evenly. The solution is solidified and precipitated in a precipitation bath. After washing and drying, polyethersulfone resin is obtained.

[0051] Comparative Example 1

[0052] The comparative example of the present invention provides a sulfone polymer, and the only difference between the preparation method of the sulfone polymer and that of Example 1 is that no nucleating agent is added.

[0053] Comparative Examples 2-9

[0054] The comparative example of the present invention is consistent with Example 1 except for the parameters listed in Table 2; wherein the addition amount refers to the mass percentage of the mole number of sodium chloride to the total mole number of phenolic monomers and sulfone monomers;

[0055] Table 2

[0056]

[0057]

[0058] Effect example

[0059] The effect examples of the present invention verify the performance of the sulfone polymers prepared in Examples 1-12 and Comparative Examples 1-9, and the particle size range of the by-product salt; wherein the performance test includes the following contents:

[0060] 1) Shear viscosity test: obtained by capillary rheometer test, the test temperature is 380℃, the shear rate is 1000S-1, and the die with an inner diameter of 1mm and a length of 40mm is used to measure the shear viscosity and shear viscosity change rate at different times. The shear viscosity change rate is the ratio of the difference between the shear viscosity at the two time points of 1h and 10min to the shear viscosity at the time point of 10min. The smaller the absolute value of the shear viscosity change rate, the better the thermal stability of the resin. In the present invention, the absolute value of the shear viscosity change rate is required to be less than 3.0%.

[0061] 2) Color plate injection molding test: The powdered resin obtained by polymerization was extruded through a twin-screw extruder to obtain resin pellets, and injection molded at 360°C to obtain a standard color plate with a thickness of 2 mm. The b value of the color plate was measured using a colorimeter according to ASTM D1925-1988;

[0062] 3) Particle size range of by-product salt: The sample was dispersed in ethanol, tested using a laser particle size analyzer, and the D50 value of the by-product salt was recorded;

[0063] The test results are shown in Table 3;

[0064] Table 3

[0065]

[0066]

[0067] It can be seen from Table 3 that when the technical solution of the present invention is adopted, the particle size of the by-product salt obtained is relatively large, at the millimeter level; the comprehensive performance of the obtained sulfone polymer is excellent, with a shear viscosity change rate of -0.52% to -0.88% and a b value of 9.16-11.89;

[0068] It can be seen from Example 1, Examples 2-5 and Comparative Examples 2-3 that the average particle size of the nucleating agent will have a significant impact on the particle size range of the by-product salt, and thus will also significantly affect the comprehensive performance of the sulfone polymer. When the average particle size of the nucleating agent is further selected to be 0.05-2.0 mm, the comprehensive performance of the obtained sulfone polymer is excellent, the shear viscosity change rate is -0.52% to -0.74%, and the b value is 9.16 to 10.95. When the particle size of the nucleating agent in Comparative Examples 2-3 is not within the range, the comprehensive performance of the obtained sulfone polymer is significantly reduced, which is reflected in the increase in the shear viscosity change rate, the deepening of the color, and the D50 particle size of the by-product salt is also significantly reduced;

[0069] It can be seen from Example 1, Examples 6-7 and Comparative Examples 4-5 that the addition speed of the nucleating agent will also have a significant impact on the product performance. When the addition speed in Comparative Example 4 is too fast, the nucleating agent entering the reaction system cannot be quickly and effectively dispersed, resulting in the nucleating agent in the reaction system agglomerating, which in turn leads to the failure of the overall reaction; when the addition speed in Comparative Example 5 is too slow, the viscosity of the reaction system exceeds 300 cps at the end of the addition, resulting in the inability to effectively increase the particle size of the by-product salt, and the comprehensive performance of the sulfone polymer is far inferior to that of Example 1, which is reflected in the increase in the shear viscosity change rate and the increase in the b value;

[0070] It can be seen from Example 1 and Comparative Example 1 that when no nucleating agent is added in Comparative Example 1, the obtained product has a darker color and a b value of 15.36; it can be seen from Example 1 and Examples 8-9 that the amount of nucleating agent added will also affect the performance of the product to a certain extent. When the amount of nucleating agent added is further preferably 0.01-0.1%, the comprehensive performance of the obtained product is more excellent;

[0071] It can be seen from Example 1, Example 10 and Comparative Example 9 that the type of nucleating agent affects the product performance, and when the water-soluble chloride is not selected, the comprehensive performance of the sulfone polymer is far inferior to that of Example 1. The shear viscosity change rate of the obtained sulfone polymer is -3.55%, and the b value is 18.71. Compared with Example 1, the shear viscosity change rate of the sulfone polymer obtained in Comparative Example 9 increases by 5.8 times, and the b value increases by 104.3%;

[0072] It can be seen from Example 1 and Comparative Examples 6-7 that when the timing of adding the nucleating agent is changed, whether the nucleating agent is added too early or too late, the particle size of the by-product salt cannot be effectively increased, and the comprehensive performance of the sulfone polymer is far inferior to that of Example 1; it can be seen from Example 1 and Comparative Example 8 that when the temperature when the nucleating agent is added is within a specific range, but the viscosity of the reaction system is not too large at the end of the addition, the comprehensive performance of the obtained sulfone polymer also shows a significant downward trend.

[0073] 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 sulfone polymer, characterized in that The shear viscosity change rate of the sulfone polymer is -0.52% to -0.88%, and the b value is 9.16-11.89; the shear viscosity change rate is tested with reference to ASTM D3835-2016, and the b value is tested by: extruding the powdered resin obtained by polymerization through a twin-screw extruder to obtain resin pellets, injection molding at 360° C. to obtain a standard color plate with a thickness of 2 mm, and using a colorimeter to measure the b value of the color plate according to ASTM D1925-1988; The preparation method of the sulfone polymer comprises the following steps: Phenol monomer, sulfone monomer, salt-forming agent, solvent and dehydrating agent are mixed and reacted at elevated temperature. When the temperature of the reaction system is 160-210° C., a nucleating agent with an average particle size of 0.05-2.0 mm is added at a rate of 1-10 g / min. After the addition, the viscosity of the reaction system is ≤300 cps. Continue the reaction until the target viscosity reaches 100-3000 cps, then add the solvent, mix with water and precipitate, then collect, crush, wash and dry the precipitate to obtain a sulfone polymer; The nucleating agent is at least one of sodium chloride and potassium chloride; The salt-forming agent is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium bicarbonate or potassium bicarbonate; The viscosity of the reaction system is tested according to ISO 1628-3-2010; The average particle size of the nucleating agent is tested with reference to GB / T 13025.1-2012.

2. The sulfone polymer according to claim 1, characterized in that When the reaction temperature is 165-180°C, the nucleating agent is added. After the addition, the viscosity of the reaction system is 100-260cps.

3. The sulfone polymer according to claim 1, characterized in that The addition rate of the nucleating agent is 3-8 g / min.

4. The sulfone polymer according to claim 1, characterized in that The average particle size of the nucleating agent is 1-1.5 mm.

5. The sulfone polymer according to claim 1, characterized in that The amount of the nucleating agent added is 0.01-0.1% based on the total mole of the phenol monomer and the sulfone monomer.

6. The sulfone polymer according to claim 1, characterized in that When adding the nucleating agent, stirring is maintained, and the stirring speed is 200-700 r / min.

7. The sulfone polymer according to claim 1, characterized in that The sulfone polymer is polysulfone, polyphenylsulfone or polyethersulfone.

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