A solution polymerized styrene-butadiene ssbr rubber and a method for preparing the same

Abstract

The application relates to a solution polymerization styrene-butadiene SSBR rubber and a preparation method thereof, and belongs to the technical field of solution polymerization styrene-butadiene rubber. The preparation raw materials of the solution polymerization styrene-butadiene SSBR rubber include 25-35 parts of styrene, 30-40 parts of butadiene, 75-85 parts of a cyclohexane solution, 0.5-1.5 parts of a polarity regulator, 2-5 parts of an atomization terminator and 0.5-2.5 parts of n-butyllithium. The preparation raw materials of the atomization terminator include 75-85 parts of isopropyl alcohol, 15-20 parts of an antioxidant 1520, 0.5-1.5 parts of cyclohexane, 0.3-0.6 parts of citric acid, 2-4 parts of a plant polyphenol extract and 0.2-0.5 parts of a crosslinking agent. By compounding the antioxidant 1520 and the multi-source purified plant polyphenol extract in the atomization terminator and matching the tannin acid-boric acid composite crosslinking system, a multiple synergistic heat-resistant protection and structure reinforcing mechanism is formed, and the defects of easy oxidative degradation, easy molecular chain rupture and serious performance attenuation of the traditional solution polymerization styrene-butadiene SSBR rubber under a high-temperature environment are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of solution polymerized styrene-butadiene rubber (SSBR) technology, specifically relating to a solution polymerized SSBR rubber and its preparation method. Background Technology

[0002] Solution-polymerized styrene-butadiene rubber (SSBR) is an elastomer formed by copolymerizing butadiene and styrene through anionic solution polymerization. It is a white, blocky rubber with three core characteristics: high anti-slip properties, low rolling resistance, and wear resistance.

[0003] However, traditional solution-polymerized styrene-butadiene rubber (SBR) has significant structural shortcomings, exhibiting poor temperature and aging resistance. In high-temperature, oxygen-rich service environments, it is highly susceptible to thermo-oxidative aging reactions. The main and side chains of the rubber molecules are easily oxidized and eroded, leading to molecular chain breakage, destruction of entangled structures, and loosening and degradation of the cross-linking network. Under long-term high-temperature conditions, microscopic defects within the material accumulate continuously, resulting in significant fluctuations in hardness, a marked decrease in core mechanical properties such as tensile strength and elongation at break, and a gradual hardening and embrittlement of the material, along with a substantial reduction in toughness and resistance to deformation. Summary of the Invention

[0004] The purpose of this invention is to provide a solution-polymerized styrene-butadiene rubber (SSBR) and its preparation method in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions: This invention provides a solution-polymerized styrene-butadiene rubber (SSBR). The raw materials for preparing the solution-polymerized SSBR include, by weight: 25-35 parts styrene, 30-40 parts butadiene, 75-85 parts cyclohexane solution, 0.5-1.5 parts polarity modifier, 2-5 parts atomization terminator, and 0.5-2.5 parts n-butyllithium. The raw materials for preparing the atomization terminator, by weight, include: 75-85 parts isopropanol, 15-20 parts antioxidant 1520, 0.5-1.5 parts cyclohexane, 0.3-0.6 parts citric acid, 2-4 parts plant polyphenol extract, and 0.2-0.5 parts crosslinking agent.

[0006] As a further optimization of the present invention, the preparation process of the atomization terminator is as follows: (a) Add isopropanol into the mixing tank and stir continuously at 60-120 r / min. While stirring, add antioxidant 1520 and continue stirring for 5-10 min to form a uniform base stop solution. (ii) Add cyclohexane solution dropwise to the base termination solution, continue stirring for 3-5 min, add citric acid, stir for 8-12 min until completely dissolved, and finally add plant polyphenol extract and cross-linking agent, continue stirring for 10-15 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution. (iii) Stir the pre-prepared liquid at 60-120 r / min for 20-30 min, then seal and let it stand for 15-20 min. Filter with a 2μm precision filter to obtain the atomization terminator.

[0007] As a further optimization of the present invention, the preparation process of the plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear pod shells, tea leaves and wisteria pods are dried at 40-50℃ to a moisture content of 5-8%, and then crushed to obtain mixed plant material; (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 50-60℃ for 30-40 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) Pass the crude extract through an HPD-400 macroporous adsorption resin column at a flow rate of 1-2 BV / h. After adsorption saturation, wash with deionized water until colorless, then elute with 50-60% ethanol as the eluent. Collect the eluent and filter it through a 0.45μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 30-40% under vacuum conditions of -0.06-0.08 MPa and water bath temperature of 40-50℃, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract.

[0008] As a further optimization of the present invention, the mass ratio of grape seeds, pomegranate peel, prickly pear pod shells, tea leaves, and wisteria pods is 3:1:6:2.

[0009] As a further optimization of the present invention, the crosslinking agent is obtained by mixing tannic acid and boric acid, wherein the mass ratio of tannic acid to boric acid is 0.6:0.3.

[0010] As a further optimization of the present invention, the concentration of the cyclohexane solution is 0.5-1.0 mol / L.

[0011] As a further optimization of the present invention, the polarity modifier is tetrahydrofuran or tetramethylethylenediamine.

[0012] This invention also provides a method for preparing solution-polymerized styrene-butadiene rubber (SSBR), comprising the following steps: S1, Deep pretreatment before polymerization: Styrene and butadiene are sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, controlling the total impurities to <5ppm, and then dried to a moisture content of <5ppm. S2, Preparation of mixed monomers: Cyclohexane solution was added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 10-15 min. Then, a polarity regulator was added and stirred for 30-45 min to obtain mixed monomers. S3, Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 35-45℃, add n-butyllithium to initiate polymerization, after the isothermal initiation is completed, gradually increase the temperature to 65-75℃ to carry out isothermal chain growth reaction, strictly control the local hot spot temperature <95℃ throughout the process, continuously stir the reaction for 60-120min, and the reaction is completed to obtain the adhesive solution. S4, Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted. The rubber solution after two-stage vacuum flash devolatilization is transported to the coagulation kettle. The internal system temperature of the coagulation kettle is stably controlled at 90±2℃, so that the rubber is uniformly precipitated and granulated to obtain the rubber solution to be terminated. S5, Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray the atomization terminating agent into the adhesive through a high-pressure atomization nozzle. When the terminating agent is sprayed in, the coagulation vessel is continuously stirred at a speed of 80-110 r / min. After stirring, let it stand for 12-18 min and maintain the reaction environment at 60-70℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained.

[0013] As a further optimization of the present invention, the two-stage vacuum flash devolatilization includes a first-stage low-pressure flash evaporation and a second-stage high-vacuum flash evaporation. The absolute pressure of the first-stage flash evaporation is 0.06-0.09 MPa, and the material temperature is 75-85℃. The absolute pressure of the second-stage flash evaporation is 0.02-0.05 MPa, and the material temperature is 80-90℃.

[0014] As a further optimization of the present invention, the radius of the high-pressure atomizing nozzle is 0.8-1.5 mm and the pressure is 0.8-1.2 MPa.

[0015] The beneficial effects of this invention are as follows: This invention combines antioxidant 1520 and multi-source purified plant polyphenol extracts in the atomization terminator, and combines them with a tannic acid-boric acid composite crosslinking system to form a multi-synergistic heat-resistant protection and structural reinforcement mechanism, effectively improving the defects of traditional solution-polymerized styrene-butadiene SSBR rubber, such as easy oxidation and degradation, easy molecular chain breakage, and severe performance degradation under high temperature conditions. Among them, antioxidant 1520 reduces the oxidative damage of the rubber matrix; the plant polyphenol extracts purified from multiple raw materials such as grape seeds, pomegranate peel, and prickly pear pod shells are rich in a large number of active phenolic hydroxyl groups, which have excellent antioxidant activity and interface modification effects. They can form stable hydrogen bonds with rubber molecular chains, helping to resist aging damage caused by high temperature and oxygen, while filling the microstructural defects of the matrix. The resistance to thermo-oxidative aging is significantly improved, avoiding the problems of hardening, brittleness, and significant reduction in toughness of traditional rubber materials after high temperature aging. This greatly improves the heat resistance stability and performance durability of solution-polymerized styrene-butadiene SSBR rubber under high temperature conditions, and broadens the application range of the material in high-temperature and long-term service scenarios. Detailed Implementation

[0016] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0017] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products. Example 1

[0018] The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.3; The preparation process of plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods were dried at 40℃ to a moisture content of 5%, and then crushed to obtain a mixed plant material (the mass ratio of grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods was 3:1:6:2). (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 50℃ for 30 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) The crude extract was passed through an HPD-400 macroporous adsorption resin column at a flow rate of 1 BV / h. After adsorption saturation, it was first washed with deionized water until colorless, and then eluted with 50% ethanol as the eluent. The eluent was collected and filtered through a 0.45 μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 30% under vacuum conditions of -0.06 MPa and water bath temperature of 40°C, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract; The preparation process of the atomization terminator is as follows: (a) Add 75 parts of isopropanol into the mixing tank and stir continuously at 60 r / min. While stirring, add 15 parts of antioxidant 1520 and stir continuously for 5 min to form a uniform base stop solution. (ii) Add 0.5 parts of cyclohexane solution (concentration of cyclohexane solution is 0.5 mol / L) dropwise to the basic termination solution, continue stirring for 3 min, add 0.3 parts of citric acid, stir for 8 min until completely dissolved, and finally add 2 parts of plant polyphenol extract and 0.2 parts of crosslinking agent, continue stirring for 10 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution; (iii) Stir the pre-prepared liquid at 60 r / min for 20 min, then seal and let it stand for 15 min, and filter it with a 2 μm precision filter to obtain the atomization terminator; Deep pretreatment before polymerization: 25 parts of styrene and 30 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, controlling the total impurities to <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 75 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 10 min. Then, 0.5 parts of tetrahydrofuran were added and stirred for 30 min to obtain mixed monomers.

[0019] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 35°C, add 0.5 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 65°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 85°C throughout the process, and continuously stir the reaction for 60 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.06 MPa and the material temperature is 75℃. The absolute pressure of the second-stage flash is 0.02 MPa and the material temperature is 80℃. The adhesive solution after two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure that the rubber is uniformly precipitated and granulated to obtain the adhesive solution to be terminated.

[0020] Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray 2 parts of atomization terminating agent into the adhesive through a high-pressure atomizing nozzle. The radius of the high-pressure atomizing nozzle is 0.8 mm and the pressure is 0.8 MPa. When the terminating agent is sprayed, the coagulation vessel is continuously stirred at a speed of 80 r / min. After stirring, let it stand for 12 min and maintain a reaction environment of 60℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained. Example 2

[0021] The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.3; The preparation process of plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods were dried at 45℃ to a moisture content of 6%, and then crushed to obtain a mixed plant material (the mass ratio of grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods was 3:1:6:2). (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 55℃ for 35 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) The crude extract was passed through an HPD-400 macroporous adsorption resin column at a flow rate of 2 BV / h. After adsorption saturation, it was first washed with deionized water until colorless, and then eluted with 55% ethanol as the eluent. The eluent was collected and filtered through a 0.45 μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 35% under vacuum conditions of -0.07 MPa and water bath temperature of 45°C, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract; The preparation process of the atomization terminator is as follows: (a) Add 80 parts of isopropanol into the mixing tank and stir continuously at 100 r / min. While stirring, add 18 parts of antioxidant 1520 and stir continuously for 8 min to form a uniform base stop solution. (ii) Add 1 part of cyclohexane solution (concentration of cyclohexane solution is 0.8 mol / L) to the basic termination solution, continue stirring for 4 min, add 0.4 parts of citric acid, stir for 10 min until completely dissolved, and finally add 3 parts of plant polyphenol extract and 0.3 parts of crosslinking agent, continue stirring for 12 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution; (iii) Stir the pre-prepared liquid at 100 r / min for 25 min, then seal and let it stand for 18 min, and filter it with a 2 μm precision filter to obtain the atomization terminator. Deep pretreatment before polymerization: 30 parts of styrene and 35 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, and the total impurities were controlled to be <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 80 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 12 min. Then, 1 part of tetrahydrofuran was added and stirred for 35 min to obtain mixed monomers.

[0022] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 40°C, add 2 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 70°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 85°C throughout the process, and continuously stir the reaction for 95 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.08 MPa and the material temperature is 80℃. The absolute pressure of the second-stage flash is 0.04 MPa and the material temperature is 85℃. The adhesive solution after two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure that the rubber is uniformly precipitated and granulated to obtain the adhesive solution to be terminated.

[0023] Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray 3 parts of atomization terminating agent into the adhesive through a high-pressure atomizing nozzle. The radius of the high-pressure atomizing nozzle is 1.2 mm and the pressure is 1 MPa. When the terminating agent is sprayed, the coagulation vessel is continuously stirred at a speed of 95 r / min. After stirring, let it stand for 16 min and maintain the reaction environment at 65℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained. Example 3

[0024] The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.3; The preparation process of plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods were dried at 50°C to a moisture content of 8%, and then crushed to obtain a mixed plant material (the mass ratio of grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods was 3:1:6:2). (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 60℃ for 40 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) The crude extract was passed through an HPD-400 macroporous adsorption resin column at a flow rate of 2 BV / h. After adsorption saturation, it was first washed with deionized water until colorless, and then eluted with 60% ethanol as the eluent. The eluent was collected and filtered through a 0.45 μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 40% under vacuum conditions of -0.08 MPa and water bath temperature of 50°C, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract; The preparation process of the atomization terminator is as follows: (a) Add 85 parts of isopropanol into the mixing tank and stir continuously at 120 r / min. While stirring, add 20 parts of antioxidant 1520 and stir continuously for 10 min to form a uniform base stop solution. (ii) Add 1.5 parts of cyclohexane solution (1.0 mol / L concentration) to the base termination solution, continue stirring for 5 min, add 0.6 parts of citric acid, stir for 12 min until completely dissolved, and finally add 4 parts of plant polyphenol extract and 0.5 parts of crosslinking agent, continue stirring for 15 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution; (iii) Stir the pre-prepared liquid at 120 r / min for 30 min, then seal and let it stand for 20 min, and filter it with a 2 μm precision filter to obtain the atomization terminator; Deep pretreatment before polymerization: 35 parts of styrene and 40 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, and the total impurities were controlled to be <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 85 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 15 min. Then 1.5 parts of tetrahydrofuran were added and stirred for 45 min to obtain mixed monomers.

[0025] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 45°C, add 2.5 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 75°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 90°C throughout the process, and continuously stir the reaction for 120 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.09 MPa and the material temperature is 85℃. The absolute pressure of the second-stage flash is 0.05 MPa and the material temperature is 90℃. The adhesive solution after two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure uniform precipitation and granulation of the rubber, thus obtaining the adhesive solution to be terminated.

[0026] Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray 5 parts of atomization terminating agent into the adhesive through a high-pressure atomizing nozzle. The radius of the high-pressure atomizing nozzle is 1.5 mm and the pressure is 1.2 MPa. When the terminating agent is sprayed, the coagulation vessel is continuously stirred at a speed of 110 r / min. After stirring, let it stand for 18 min and maintain the reaction environment at 70℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained. Example 4

[0027] The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.3; The preparation process of plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods were dried at 45℃ to a moisture content of 6%, and then crushed to obtain a mixed plant material (the mass ratio of grape seeds, pomegranate peel, prickly pear bean pod shells, tea leaves, and wisteria pods was 3:1:6:2). (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 55℃ for 35 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) The crude extract was passed through an HPD-400 macroporous adsorption resin column at a flow rate of 2 BV / h. After adsorption saturation, it was first washed with deionized water until colorless, and then eluted with 55% ethanol as the eluent. The eluent was collected and filtered through a 0.45 μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 35% under vacuum conditions of -0.07 MPa and water bath temperature of 45°C, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract; The preparation process of the atomization terminator is as follows: (a) Add 80 parts of isopropanol into the mixing tank and stir continuously at 100 r / min. While stirring, add 18 parts of antioxidant 1520 and stir continuously for 8 min to form a uniform base stop solution. (ii) Add 1 part of cyclohexane solution (concentration of cyclohexane solution is 0.8 mol / L) to the basic termination solution, continue stirring for 4 min, add 0.4 parts of citric acid, stir for 10 min until completely dissolved, and finally add 3 parts of plant polyphenol extract and 0.3 parts of crosslinking agent, continue stirring for 12 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution; (iii) Stir the pre-prepared liquid at 100 r / min for 25 min, then seal and let it stand for 18 min, and filter it with a 2 μm precision filter to obtain the atomization terminator. Deep pretreatment before polymerization: 30 parts of styrene and 35 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, and the total impurities were controlled to be <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 80 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 12 min. Then, 1 part of tetramethylethylenediamine was added and stirred for 35 min to obtain mixed monomers.

[0028] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 40°C, add 2 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 70°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 85°C throughout the process, and continuously stir the reaction for 95 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.08 MPa and the material temperature is 80℃. The absolute pressure of the second-stage flash is 0.04 MPa and the material temperature is 85℃. The adhesive solution after two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure that the rubber is uniformly precipitated and granulated to obtain the adhesive solution to be terminated.

[0029] Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray 3 parts of atomization terminating agent into the adhesive through a high-pressure atomizing nozzle. The radius of the high-pressure atomizing nozzle is 1.2 mm and the pressure is 1 MPa. When the terminating agent is sprayed, the coagulation vessel is continuously stirred at a speed of 95 r / min. After stirring, let it stand for 16 min and maintain the reaction environment at 65℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained.

[0030] Comparative Example 1 The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.3; The preparation process of the atomization terminator is as follows: (a) Add 80 parts of isopropanol into the mixing tank and stir continuously at 100 r / min. While stirring, add 18 parts of antioxidant 1520 and stir continuously for 8 min to form a uniform base stop solution. (ii) Add 1 part of cyclohexane solution (concentration of cyclohexane solution is 0.8 mol / L) to the basic termination solution, continue stirring for 4 min, add 0.4 parts of citric acid, stir for 10 min until completely dissolved, and finally add 3 parts of plant polyphenol extract and 0.3 parts of crosslinking agent, continue stirring for 12 min to make tea polyphenols uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution. (iii) Stir the pre-prepared liquid at 100 r / min for 25 min, then seal and let it stand for 18 min, and filter it with a 2 μm precision filter to obtain the atomization terminator. Deep pretreatment before polymerization: 30 parts of styrene and 35 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, and the total impurities were controlled to be <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 80 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 12 min. Then, 1 part of tetrahydrofuran was added and stirred for 35 min to obtain mixed monomers.

[0031] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 40°C, add 2 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 70°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 85°C throughout the process, and continuously stir the reaction for 95 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.08 MPa and the material temperature is 80℃. The absolute pressure of the second-stage flash is 0.04 MPa and the material temperature is 85℃. The adhesive solution after two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure that the rubber is uniformly precipitated and granulated to obtain the adhesive solution to be terminated.

[0032] Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray 3 parts of atomization terminating agent into the adhesive through a high-pressure atomizing nozzle. The radius of the high-pressure atomizing nozzle is 1.2 mm and the pressure is 1 MPa. When the terminating agent is sprayed, the coagulation vessel is continuously stirred at a speed of 95 r / min. After stirring, let it stand for 16 min and maintain the reaction environment at 65℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained.

[0033] Comparative Example 2 Deep pretreatment before polymerization: 30 parts of styrene and 35 parts of butadiene were sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, and the total impurities were controlled to be <5ppm. After impurity removal, they were dried to a moisture content of <5ppm. Preparation of mixed monomers: 80 parts of cyclohexane solution were added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 12 min. Then, 1 part of tetrahydrofuran was added and stirred for 35 min to obtain mixed monomers.

[0034] Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 40°C, add 2 parts of n-butyllithium to initiate polymerization, and after the isothermal initiation is completed, gradually increase the temperature to 70°C to carry out the isothermal chain growth reaction. Strictly control the local hot spot temperature to 85°C throughout the process, and continuously stir the reaction for 95 minutes. After the reaction is completed, the adhesive solution is obtained. Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted, which includes a first-stage low-pressure flash and a second-stage high-vacuum flash. The absolute pressure of the first-stage flash is 0.08 MPa and the material temperature is 80℃. The absolute pressure of the second-stage flash is 0.04 MPa and the material temperature is 85℃. The rubber solution after the two-stage vacuum flash devolatilization is transported to a coagulation reactor. The internal system temperature of the coagulation reactor is stably controlled at 90℃ to ensure uniform precipitation and granulation of the rubber, thus obtaining solution-polymerized styrene-butadiene rubber (SSBR).

[0035] Performance testing (i) The solution-polymerized styrene-butadiene rubbers prepared in Examples 1-4 and Comparative Examples 1-2 were tested for Shore hardness according to GB / T531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore hardness)". (ii) The tensile strength and elongation at break of the solution-polymerized styrene-butadiene rubbers prepared in Examples 1-4 and Comparative Examples 1-2 were tested in accordance with GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The test results are shown in Table 1.

[0036] Table 1

[0037] As can be seen from Table 1, the Shore A hardness of Examples 1-4 is 65-68, which is much higher than that of Comparative Examples 1 and 2 (55 and 59 respectively). The overall hardness of the modified rubber is significantly improved, and the structural density is better. The strength of Examples 1-4 is 22-25 MPa, while that of Comparative Examples 1-2 is only 14-16 MPa, indicating a significant enhancement in mechanical load-bearing capacity. Among them, Example 2 shows the best strength performance. The elongation of Examples 1-4 is 303%-346%, which is significantly better than that of Comparative Examples 1-2 (256% and 273% respectively), indicating better material toughness and resistance to deformation.

[0038] (III) The solution-polymerized styrene-butadiene rubbers prepared in Examples 1-4 and Comparative Examples 1-2 were tested in accordance with GB / T1634.2-2019 "Determination of the load deformation temperature of plastics - Part 2: Plastics and hard rubber". The test conditions were: 70℃ and 72 hours of high-temperature aging. The test results are shown in Table 2.

[0039] Table 2

[0040] As can be seen from Table 2, the hardness of the samples all increased after aging, but the examples were more stable than the comparative examples; the tensile strength retention rate of the examples was 90%-92%, while that of the comparative examples was only 71%-75%, and the modified system had outstanding resistance to high temperature aging damage; the elongation at break retention rate of the examples was 80%-86%, which was far better than that of the comparative examples, and it still maintained good flexibility at high temperature.

[0041] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A solution-polymerized styrene-butadiene rubber (SSBR), characterized in that, The raw materials for preparing the solution-polymerized styrene-butadiene SSBR rubber, by weight, include: 25-35 parts styrene, 30-40 parts butadiene, 75-85 parts cyclohexane solution, 0.5-1.5 parts polarity modifier, 2-5 parts atomization terminator, and 0.5-2.5 parts n-butyllithium; The raw materials for preparing the atomization terminator, by weight, include: 75-85 parts isopropanol, 15-20 parts antioxidant 1520, 0.5-1.5 parts cyclohexane, 0.3-0.6 parts citric acid, 2-4 parts plant polyphenol extract, and 0.2-0.5 parts crosslinking agent.

2. The solution-polymerized styrene-butadiene SSBR rubber according to claim 1, characterized in that, The preparation process of the atomization terminator is as follows: (a) Add isopropanol into the mixing tank and stir continuously at 60-120 r / min. While stirring, add antioxidant 1520 and continue stirring for 5-10 min to form a uniform base stop solution. (ii) Add cyclohexane solution dropwise to the base termination solution, continue stirring for 3-5 min, add citric acid, stir for 8-12 min until completely dissolved, and finally add plant polyphenol extract and cross-linking agent, continue stirring for 10-15 min to make the plant polyphenol extract uniformly dispersed and dissolved in the composite system to obtain the pre-prepared solution. (iii) Stir the pre-prepared liquid at 60-120 r / min for 20-30 min, then seal and let it stand for 15-20 min. Filter with a 2μm precision filter to obtain the atomization terminator.

3. The solution-polymerized styrene-butadiene rubber (SSBR) according to claim 2, characterized in that, The preparation process of the plant polyphenol extract is as follows: (a) Grape seeds, pomegranate peel, prickly pear pod shells, tea leaves and wisteria pods are dried at 40-50℃ to a moisture content of 5-8%, and then crushed to obtain mixed plant material; (ii) Using 50% ethanol as solvent, with a material-to-liquid ratio of 1:15, ultrasonically extract at 50-60℃ for 30-40 min, extract twice in total, combine the extracts, and coarsely filter through a 200-mesh filter to obtain crude extract; (iii) Pass the crude extract through an HPD-400 macroporous adsorption resin column at a flow rate of 1-2 BV / h. After adsorption saturation, wash with deionized water until colorless, then elute with 50-60% ethanol as the eluent. Collect the eluent and filter it through a 0.45μm microporous membrane to obtain the purified extract. (iv) The purified extract was concentrated under reduced pressure to a solid content of 30-40% under vacuum conditions of -0.06-0.08 MPa and water bath temperature of 40-50℃, and then freeze-dried to obtain a powder to obtain a plant polyphenol extract.

4. The solution-polymerized styrene-butadiene SSBR rubber according to claim 3, characterized in that, The mass ratio of grape seeds, pomegranate peel, prickly pear pod shells, tea leaves, and wisteria pods is 3:1:6:

2.

5. The solution-polymerized styrene-butadiene rubber (SSBR) according to claim 1, characterized in that, The crosslinking agent is obtained by mixing tannic acid and boric acid, with a mass ratio of tannic acid to boric acid of 0.6:0.

3.

6. The solution-polymerized styrene-butadiene SSBR rubber according to claim 1, characterized in that, The concentration of the cyclohexane solution is 0.5-1.0 mol / L.

7. The solution-polymerized styrene-butadiene rubber (SSBR) according to claim 1, characterized in that, The polarity modifier is tetrahydrofuran or tetramethylethylenediamine.

8. A method for preparing solution-polymerized styrene-butadiene rubber (SSBR) according to any one of claims 1-7, characterized in that, Includes the following steps: S1, Deep pretreatment before polymerization: Styrene and butadiene are sequentially passed through ZSM-5 modified molecular sieve and supported copper-based catalyst to remove impurities, controlling the total impurities to <5ppm, and then dried to a moisture content of <5ppm. S2, Preparation of mixed monomers: Cyclohexane solution was added to the polymerization reactor and stirred continuously at a speed of 20 r / min. Styrene and butadiene were added and stirred for 10-15 min. Then, a polarity regulator was added and stirred for 30-45 min to obtain mixed monomers. S3, Polymerization: Add the mixed monomers to the polymerization reactor, keep the reactor sealed and purged with nitrogen for protection, control the temperature to 35-45℃, add n-butyllithium to initiate polymerization, after the isothermal initiation is completed, gradually increase the temperature to 65-75℃ to carry out isothermal chain growth reaction, strictly control the local hot spot temperature <95℃ throughout the process, continuously stir the reaction for 60-120min, and the reaction is completed to obtain the adhesive solution. S4, Two-stage vacuum flash devolatilization: Two-stage vacuum flash devolatilization is adopted. The rubber solution after two-stage vacuum flash devolatilization is transported to the coagulation kettle. The internal system temperature of the coagulation kettle is stably controlled at 90±2℃, so that the rubber is uniformly precipitated and granulated to obtain the rubber solution to be terminated. S5, Mild atomization termination treatment: Add the adhesive to be terminated to the coagulation vessel, and spray the atomization terminating agent into the adhesive through a high-pressure atomization nozzle. When the terminating agent is sprayed in, the coagulation vessel is continuously stirred at a speed of 80-110 r / min. After stirring, let it stand for 12-18 min and maintain the reaction environment at 60-70℃. After the reaction is completed, solution-polymerized styrene-butadiene rubber (SSBR) is obtained.

9. The method for preparing solution-polymerized styrene-butadiene rubber (SSBR) according to claim 8, characterized in that, The two-stage vacuum flash devolatilization includes a first-stage low-pressure flash evaporation and a second-stage high-vacuum flash evaporation. The absolute pressure of the first-stage flash evaporation is 0.06-0.09 MPa, and the material temperature is 75-85℃. The absolute pressure of the second-stage flash evaporation is 0.02-0.05 MPa, and the material temperature is 80-90℃.

10. The method for preparing solution-polymerized styrene-butadiene rubber (SSBR) according to claim 8, characterized in that, The high-pressure atomizing nozzle has a radius of 0.8-1.5 mm and a pressure of 0.8-1.2 MPa.

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