Chain-end polyvinylpyridine modified ssbr, preparation method thereof, tread rubber, tire and vehicle

Abstract

Chain end polyvinyl pyridine modified SSBR and preparation method thereof, tread rubber, tire and vehicle belong to the technical field of green rubber tire production and manufacturing. The middle of the molecular chain of the modified SSBR is styrene and butadiene, which is a random copolymer linear structure; the chain end is capped with polyvinyl pyridine. The material is mainly applied in green tires using white carbon black as filler, a plurality of hydrogen bonds are formed between the rubber molecular terminal polyvinyl pyridine and the surface silicon hydroxyl of the white carbon black, and the SSBR molecular terminal is further fixed on the surface of the white carbon black, so as to reduce the rolling resistance of the tire.

Description

Technical Field

[0001] This invention belongs to the field of green rubber tire manufacturing technology, specifically relating to a modified SSBR whose ends can be fixed to the surface of silica via hydrogen bonds and its preparation method, as well as the corresponding tread rubber and tire, which has the beneficial effect of low rolling resistance. Background Technology

[0002] Solution-polymerized styrene-butadiene rubber (SSBR) is a key material for manufacturing high-performance tires, especially green tires. Green tires use silica as the main reinforcing filler because it can significantly reduce tire rolling resistance, reduce vehicle fuel consumption, and provide excellent anti-skid performance, making it an important development direction for the tire industry.

[0003] In green tires, the surface of precipitated silica (SSBR) filler is rich in silanol groups (-SiOH). During tire use, the ends of rubber molecular chains that do not interact with the filler will experience internal friction due to free movement, which is one of the main reasons for increased rolling resistance. Therefore, by chemically modifying the ends of SSBR molecular chains to introduce polar functional groups that can interact with the silanol groups on the precipitated silica surface, the ends of the rubber molecular chains can be anchored to the filler surface, thereby reducing tire rolling resistance.

[0004] Currently, there is some research on the functionalization modification technology of SSBR at the chain ends. For example, patent CN112707994A discloses a method for preparing SSBR with double-terminated epoxy groups using an epoxidation initiator. In this method, the epoxy groups at the ends of the rubber molecules can react with the silanol groups on the surface of silica to form chemical bonds, thereby reducing the internal friction at the molecular ends. However, the epoxidation initiator (RAFT reagent) used in this method is complex to synthesize and difficult to achieve large-scale industrial production, causing this technology to remain in the laboratory research stage.

[0005] Another study by Dr. Liu Xiao (his 2009 doctoral dissertation at Beijing University of Chemical Technology, "Molecular Structure of Energy-Saving SSBR and Design, Preparation, Structure and Performance Study of its Nano-Reinforcing Materials") employed anionic polymerization to prepare SSBRs with dual-terminal silanyl ethoxy groups (-Si(OR)3), allowing the terminal silanyl ethoxy groups to react with the silanyl hydroxyl groups on the surface of silica. However, in the actual synthesis process, this technique used a modifier containing both C-Cl groups and silanyl ethoxy groups to react with the active chain ends of the polymer. Because the carbanions at the active chain ends of the polymer have high reactivity, they not only attack the target C-Cl groups of the modifier but also undergo side reactions attacking the silanyl ethoxy groups themselves. This leads to two problems: first, the modifier also acts as a coupling agent, inducing unnecessary branching or cross-linking; second, the silanyl ethoxy groups are partially consumed during grafting, reducing the number of effective functional groups at the end of the final product, thus weakening its interaction with silica during subsequent preparation of tread rubber and failing to achieve the expected modification effect.

[0006] Therefore, existing SSBR chain-end functionalization technologies either suffer from the difficulty and high cost of industrializing key reagents, or have drawbacks such as numerous side reactions during modification and functionalization efficiency that does not meet design goals. Developing a feasible, highly efficient, and stable SSBR chain-end modification method is of great significance for advancing green tire technology. Summary of the Invention

[0007] This application further improves the configuration and preparation method of the rubber in order to solve the above-mentioned technical problems. One objective of this invention is to provide chain-end polyvinylpyridine modified SSBR and its preparation method; another objective is to provide a corresponding tread rubber; a third objective is to provide a corresponding tire; and a fourth objective is to provide a vehicle using the tire.

[0008] The specific technical solution is explained below:

[0009] The chain-terminated polyvinylpyridine-modified SSBR has the molecular structure shown in formula (I):

[0010] (I);

[0011] In formula (Ⅰ):

[0012] The value of 'a' makes the molecular mass of styrene structural units account for 12-30% of the total molecular mass;

[0013] The value of (b+c) results in the molecular mass of butadiene structural units accounting for 70-85% of the total molecular mass;

[0014] The value of d makes the molecular mass of the vinylpyridine structural unit account for 0.2~3% of the total molecular mass.

[0015] In a preferred embodiment, b / (b+c) is between 0.35 and 0.7.

[0016] In the above technical solution, 'a' represents the number of styrene structural units in the molecule; 'b' and 'c' represent the number of 1,2- and 1,4- structural units of butadiene in the molecule, respectively. Butadiene structural units can provide rubber elasticity, so their content is relatively high; 'd' represents the number of vinylpyridine structural units formed by the end-capping modifier in the molecule. Generally, the content of the modifier should not be too high, as too much will lead to a decrease in material performance.

[0017] This invention adjusts the content of various monomers by adding them to the reactor; controls the 1,2-structure of butadiene by using a regulator; and the reaction temperature can also affect the formation of the 1,2-structure of butadiene to a certain extent.

[0018] In a preferred embodiment, the molecular weight is 270,000 to 400,000, and the molecular weight distribution is between 1.10 and 1.90.

[0019] The preparation method of chain-terminated polyvinylpyridine modified SSBR includes the following steps:

[0020] S1: Add the solvent to the reactor, then add a regulator and an activator, such that the regulator content is 50~500 ppm and the activator content is 20~600 ppm; then add butadiene monomer and styrene monomer, and the mixed monomer concentration in the reactor is 20~200 kg / m³. 3 The mass fraction of styrene monomer accounts for 12-30% of the mixed monomer content; the temperature inside the polymerization reactor is raised to 40-50℃, and an initiator is added to copolymerize butadiene monomer and styrene monomer;

[0021] S2: After the copolymerization reaction is completed, vinylpyridine is added to the reactor for end-capping reaction, and the reaction temperature is controlled at -70~30℃;

[0022] S3: After the end-capping reaction is complete, a terminator is added to terminate the reaction with the active center at the end of the rubber molecular chain. The active center is composed of carbanion and lithium ion. The molar amount of the terminator is 1 to 2 times the molar amount of the active center.

[0023] S4: The solvent is removed from the adhesive solution after the termination reaction is completed to form adhesive water, and the adhesive water is dehydrated to obtain dry rubber.

[0024] In a preferred embodiment, the regulator is selected from tetrahydrofurfuryl ethyl ether, furfuryl propane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, and triethylamine;

[0025] The activator is tetrahydrofuran;

[0026] The initiator is an alkyl lithium, wherein the alkyl group in the alkyl lithium comprises a C2-C10 straight-chain or branched saturated alkane;

[0027] The solvent is selected from one or two of cyclohexane, n-hexane, cyclopentane, n-heptane, benzene, toluene, and ethylbenzene;

[0028] The terminating agent is an alcoholic organic compound or a phenolic organic compound.

[0029] In a further embodiment, the material passes through the first reactor, the middle reactor, and the final reactor in sequence;

[0030] The solvent, butadiene monomer, styrene monomer, regulator, activator and initiator are all added from the bottom of the first batch.

[0031] During the reaction, the material moves upward from the bottom of the reactor and flows out from the top to the bottom of the next reactor;

[0032] The butadiene monomer and styrene monomer undergo complete copolymerization in the first or second reactor.

[0033] Vinylpyridine is added from the top of the first vessel, the bottom of the middle vessel, the top of the middle vessel, and the bottom of the last vessel;

[0034] The terminator is added from the bottom or top of the final vessel;

[0035] Terminator should not be added simultaneously with vinylpyridine.

[0036] The tread rubber comprises modified SSBR as described in any of the above technical solutions, or modified SSBR prepared by the preparation method described in any of the above technical solutions.

[0037] In a further embodiment, precipitated silica is included, and the modified SSBR is connected to the precipitated silica by at least hydrogen bonds.

[0038] The tires used the aforementioned tread rubber.

[0039] The vehicle used the aforementioned tires.

[0040] In summary, the technical solution described in this invention has the following main beneficial effects:

[0041] Compared with existing technologies, the technical solution of this invention uses vinylpyridine as the end-capping agent of SSBR. Vinylpyridine has the ability of negative ion polymerization. After the styrene and butadiene monomers have reacted completely, vinylpyridine is added to carry out the SSBR end-capping reaction. When vinylpyridine reacts with the negative ion active center, only vinyl groups can react and no other groups participate in the reaction, which can effectively avoid the generation of side reactions and ensure more stable rubber product quality.

[0042] Furthermore, existing technologies typically use SSBR chain end grafting to react with the silanol groups on the surface of silica to form chemical bonding points. However, this embodiment uses multiple pyridine groups and nitrogen elements to form multiple hydrogen bonds with the silanol groups on the surface of silica, causing the ends of rubber molecules to adhere to the silica surface. In rubber preparation, hydrogen bonding is easier to achieve than chemical bonding, reducing the difficulty of rubber preparation and also significantly reducing the rolling resistance of tread rubber materials.

[0043] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Detailed Implementation

[0044] The present invention will be further explained in conjunction with the embodiments:

[0045] The core technical problem faced by the technical solution of this application embodiment stems from the inventor's accurate understanding of the prior art. Therefore, how to provide a modified SSBR that can be industrially applied and has a relatively ideal number of effective functional groups is a technical problem that the inventor urgently needs to solve.

[0046] It should be noted that the embodiments do not constitute a limitation on the scope of protection of the claims of this invention. All technical solutions that can be reasonably expected by those skilled in the art based on the technical concepts provided / proved by the embodiments should be covered within the scope of protection of the claims of this invention.

[0047] Details are as follows:

[0048] The preparation method of the modified SSBR in the implementation embodiment is as follows:

[0049] Step 1: Butyllithium-initiated copolymerization of butadiene and styrene: The polymerization can be carried out in a small-scale stainless steel reactor (0.1~50 L) or a reactor (0.5~10 m³). 3 Pilot-scale stainless steel reactor, or 20~80 m 3 The industrial equipment uses a stainless steel reactor. First, the solvent is added to the reactor; next, a regulator and an activator are added, with the regulator at a concentration of 50-500 ppm and the activator at a concentration of 20-600 ppm; then, a mixed monomer of butadiene and styrene is added, with a mixed monomer concentration of 20-200 kg / m³ in the reactor. 3 The mass fraction of styrene monomer accounts for 12-30% of the mixed monomer content; the temperature inside the polymerization reactor is raised to 40-50℃, 50-500ppm of initiator is added and reacted for 30-120 minutes to copolymerize butadiene and styrene, and the reactor temperature is maintained at 40-50℃ through the jacket and internal cooling pipe.

[0050] The polymerization reaction of styrene and butadiene monomers initiated by lithium is as follows:

[0051] .

[0052] Step 2: After the butadiene and styrene monomers have completely reacted, vinylpyridine is diluted to 5-30% with cyclohexane, and then vinylpyridine is added to the reactor for end-capping reaction. The reaction takes about 60 minutes, and the reaction temperature is controlled at -70 to 30°C using a jacket and internal cooling pipe. The mass of vinylpyridine added accounts for 0.1-10% of the total mass of the final rubber molecules.

[0053] The vinylpyridine-terminated SSBR reaction is as follows:

[0054] .

[0055] Step 3: After the vinylpyridine reaction is complete, add acidic organic compounds such as alcohols or phenols to react with the anionic active centers at the ends of the rubber molecular chains—carbanions (C). - ) and lithium cations (Li + The reaction is terminated by ion pairs formed by the ions. The molar amount of the terminator is 1 to 2 times the molar amount of the active center.

[0056] The termination reaction of polyvinylpyridine functionalization of SSBR is as follows:

[0057] .

[0058] Step 4: The polymerized rubber solution is piped into a coagulation reactor to remove cyclohexane solvent by washing. The water temperature in the coagulation reactor is 80-100℃, and the cyclohexane solvent removal rate is required to be above 98%. The solvent-removed rubber particles are then piped to an extruder for initial dehydration through physical extrusion. The next step involves further dehydration through an expander, followed by final dehydration in a long-net drying oven to obtain a dried rubber product with a volatile matter content of less than 0.6%.

[0059] The polymerization method described in this embodiment is a continuous polymerization. The reaction apparatus consists of three polymerization reactors connected in series: a first reactor, a middle reactor, and a final reactor. Reactants are added from the bottom of the reactor and flow out from the top to the bottom of the next reactor. During the polymerization of styrene and butadiene, solvents, mixed monomers, regulators, activators, and initiators are added from the bottom of the first reactor. During the reaction, the materials move in a laminar flow manner within the reactor as much as possible; that is, the materials in the vertical direction of the reactor are kept as unmixed as possible, while the materials in the horizontal direction are mixed uniformly. Materials are continuously injected from the bottom of the reactor, causing the materials inside to move upwards, and the materials flow out from the top of the reactor to the bottom of the next reactor. During the reaction, the styrene and butadiene monomers should react completely in the first or middle reactor; vinylpyridine can be added from the top of the first reactor, the bottom of the middle reactor, or the top and bottom of the final reactor; the terminator can be added from the bottom or top of the final reactor, but the terminator should not be added simultaneously with vinylpyridine.

[0060] In the above preparation method, the initiator is alkyl lithium, wherein the alkyl group includes C2-C10 straight-chain or branched saturated alkanes; the solvent used includes one or two of various aliphatic hydrocarbons and aromatic hydrocarbons such as cyclohexane, n-hexane, cyclopentane, n-heptane, benzene, toluene, and ethylbenzene; the regulator is an ether or amine regulator, including tetrahydrofurfuryl ethyl ether, furfuryl propane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, and triethylamine; the activator is tetrahydrofuran; the structure of the end-capping agent is shown below:

[0061] or ;

[0062] Wherein R1 is a straight-chain or branched saturated alkane of C1-C20, and R2, R3, and R4 are straight-chain or branched saturated alkane of C0-C20; preferably, R1 is a straight-chain or branched saturated alkane of C1-C5, and R2, R3, and R4 are straight-chain or branched saturated alkane of C1-C6.

[0063] Example 1:

[0064] Cyclohexane solvent, furfuryl propane as a modifier, tetrahydrofuran as an activator, a mixture of styrene and butadiene monomers, and butyllithium were simultaneously drawn from 80 m 3 The mixture is added to the bottom of the first reactor, where the concentration of the regulator in the solvent is 50 ppm and the concentration of the mixed monomers in the solvent oil is 20 kg / m³. 3 The activator was 600 ppm and the initiator was 130 ppm. The styrene content in the mixed monomers was 12% by mass. The reaction temperature was 40℃, and the overall flow rate of the material added to the reactor was 120 m / s. 3 The continuous polymerization was carried out using a three-reactor series method, with a residence time of 40 min in each reactor. Vinylpyridine (618 ppm) was added from the bottom of the middle reactor at a reaction temperature of 30°C. After the reaction was completed, methanol was added as a terminator to the bottom of the final reactor. The resulting rubber solution was then added to a coagulation reactor, where the solvent was removed by washing with water and the solution was dried to obtain a rubber sample.

[0065] Example 2:

[0066] A mixed solvent of n-hexane and cyclohexane, a modifier of tetrahydrofurfuryl ethyl ether, an activator of tetrahydrofuran, a styrene-butadiene mixture monomer, and ethyl lithium were simultaneously drawn from 20 m 3 The mixture is added to the bottom of the first reactor, wherein the concentration of the regulator in the solvent is 500 ppm, and the concentration of the mixed monomers in the solvent oil is 200 kg / m³. 3 The activator was 20 ppm and the initiator was 500 ppm. The styrene content in the mixed monomers was 30% by mass. The reaction temperature was 50°C, and the overall flow rate of the materials added to the reactor was 40 m / s.3 The continuous polymerization was carried out using a three-reactor series method, with a residence time of 30 min in each reactor. Vinylpyridine (400 ppm) was added from the top of the middle reactor, and the reaction temperature was -70°C. After the reaction was completed, methanol was added as a terminator to the bottom of the final reactor. The rubber solution was then added to a coagulation reactor, where the solvent was removed by washing with water, and the sample was dried to obtain a rubber sample.

[0067] Example 3:

[0068] Cyclopentane solvent, ethylene glycol dimethyl ether as a modifier, tetrahydrofuran as an activator, a mixture of styrene and butadiene monomers, and butyllithium were simultaneously drawn from 50 m 3 The mixture is added to the bottom of the first reactor, where the concentration of the regulator in the solvent is 270 ppm and the concentration of the mixed monomers in the solvent oil is 100 kg / m³. 3 The activator was 400 ppm and the initiator was 280 ppm. The styrene content in the mixed monomers was 20% by mass. The reaction temperature was 50°C, and the overall flow rate of the materials added to the reactor was 25 m / s. 3 The continuous polymerization was carried out using a three-reactor series method, with a residence time of 120 min in each reactor. Vinylpyridine (1500 ppm) was added from the bottom of the middle reactor at a reaction temperature of -20°C. After the reaction was completed, methanol was added as a terminator to the bottom of the final reactor. The resulting rubber solution was then added to a coagulation reactor, where the solvent was removed by washing with water and the solution was dried to obtain a rubber sample.

[0069] Example 4:

[0070] A mixed solvent of benzene and toluene, a modifier of diethylene glycol dimethyl ether, an activator of tetrahydrofuran, a styrene-butadiene mixed monomer, and butyllithium were simultaneously added from the bottom of a 30L reactor. The concentration of the modifier in the solvent was 260 ppm, and the concentration of the mixed monomer in the solvent oil was 50 kg / m³. 3 The activator was 180 ppm and the initiator was 160 ppm. The styrene content in the monomer mixture was 25% by mass. The reaction temperature was 45℃, the overall material flow rate into the reactor was 30 L / h, and a three-reactor series polymerization method was used for continuous polymerization, with a residence time of 60 min in each reactor. Vinylpyridine (500 ppm) was added from the bottom of the final reactor at a reaction temperature of 0℃. After the reaction was completed, ethanol was added as a terminator at the top of the final reactor. The rubber solution was then added to a coagulation reactor, the solvent was removed by washing with water, and the sample was dried to obtain a rubber sample.

[0071] Example 5:

[0072] A mixed solvent of n-heptane and ethylbenzene, N,N,N',N'-tetramethylethylenediamine as a modifier, tetrahydrofuran as an activator, a mixture of styrene and butadiene monomers, and butyllithium were simultaneously extracted from 2 m3 The mixture is added to the bottom of the first reactor, where the concentration of the regulator in the solvent is 80 ppm, and the concentration of the mixed monomers in the solvent oil is 120 kg / m³. 3 The activator was 290 ppm and the initiator was 320 ppm. The styrene content in the mixed monomers was 17% by mass. The reaction temperature was 43℃, and the overall flow rate of the materials added to the reactor was 4 m / s. 3 The continuous polymerization was carried out using a three-reactor series process, with a residence time of 30 min in each reactor. Vinylpyridine was added from the bottom of the intermediate reactor at a concentration of 2.4 kg / m³. 3 The reaction temperature was -20℃. After the reaction was complete, methanol, the terminator, was added to the bottom of the final reactor. The rubber solution was then added to a coagulation reactor, where the solvent was removed by washing with water, and the sample was dried to obtain a rubber sample.

[0073] Comparative Example 1:

[0074] The difference between this comparative example and Example 1 is as follows:

[0075] The end-capping reaction was cancelled.

[0076] Comparative Example 2:

[0077] Commercially available Dushanzi Petrochemical SSBR 2564T grade rubber.

[0078] Comparative Example 3:

[0079] Commercially available SSBR 2550 grade rubber from LG Corporation of South Korea.

[0080] The molecular weight (gel permeation chromatography), structural analysis (NMR, IR), Mooney viscosity, and glass transition temperature (DSC) data of the rubber products corresponding to Examples 1-5 and Comparative Examples 1-3 are shown in Table 1 below:

[0081] Table 1 Performance parameters of rubber products corresponding to Examples 1-5 and Comparative Examples 1-3

[0082] serial number Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Number average molecular weight × 10 4 > 26.8 39.7 33.6 30.6 48.0 27.1 33.4 34.3 Molecular weight distribution 1.12 1.88 1.48 1.37 1.76 1.14 1.71 1.76 Vinylpyridine content (%) 2.9 0.2 1.5 1.1 2.0 0 0 0 Styrene content (%) 12.4 29.8 20.4 24.8 17.3 12.2 24.7 25.6 Mooney (ML 1+4 100℃) 48.0 71.3 53.6 39.5 74.3 54.9 52.7 54.8 Vinyl content (%) 36.1 69.3 53.1 39.8 67.4 36.6 63.8 62.7 Glass transition temperature (°C) -49.0 -46.2 -47.6 -54.8 -41.3 -48.2 -45.9 -47.3

[0083] As can be seen from Table 1 above:

[0084] Examples 1-5 prepared chain-terminated polyvinylpyridine-modified SSBR, and the molecular structure parameters of the products are as follows:

[0085] The content of styrene structural units corresponds to the value a, which ranges from 12.4% to 29.8%; the total content of butadiene structural units corresponds to the value (b+c), which ranges from 68.7% to 87.4%; the content of vinylpyridine structural units corresponds to the value d, which ranges from 0.2% to 2.9%; the b / (b+c) value ranges from 0.361 to 0.693; the number-average molecular weight ranges from 268,000 to 480,000, and the molecular weight distribution ranges from 1.12 to 1.88.

[0086] Compared with Comparative Example 1 (without end-capping modification) and Comparative Examples 2 and 3 (common SSBR products), the significant improvement in the molecular structure of the products in this invention is the successful introduction of 0.2% to 2.9% polyvinylpyridine segments at the molecular chain ends. The impact of this structural modification on the basic properties of the products is as follows: under similar structural parameters such as styrene content and vinyl content (e.g., Example 1 and Comparative Example 1), the Mooney viscosity (48.0) of Example 1 with polyvinylpyridine end-capping is significantly lower than that of Comparative Example 1 (54.9), indicating improved processing fluidity of the modified SSBR; simultaneously, the glass transition temperature (-49.0℃) of Example 1 is slightly lower than that of Comparative Example 1 (-48.2℃), indicating that the end-capping modification does not negatively affect the low-temperature performance of the rubber. This confirms that the end-capping polyvinylpyridine modification described in this invention is technically feasible and effective, providing a structural basis for achieving hydrogen bonding between the rubber molecule ends and the silica filler.

[0087] In this embodiment, the mixing process for preparing tread rubber using modified SSBR is as follows:

[0088] Set the temperature of the Hack mixer to 55°C and the speed to 50 rpm. Then, put the styrene-butadiene rubber, butadiene rubber, and environmentally friendly aromatic oil into the mold cavity and mix for 2 minutes. Next, add silica to the internal mixer mold cavity in four batches. At the same time as adding silica, add stearic acid, zinc oxide, antioxidant, and coupling agent and mix for 5 minutes to ensure thorough mixing. Heat the Hack mixer to 150°C and adjust the speed to 25 rpm to heat-treat the compound for 5 minutes. Discharge the compound and cool it to room temperature.

[0089] Then, sulfur and accelerators (accelerator D + accelerator NS, where accelerator D is diphenylguanidine and accelerator NS is N-tert-butyl-2-benzothiazole sulfenamide) were added to the rubber compound on a two-roll mill, and the compound was sheeted nine times to ensure thorough mixing of the components. The rubber compound samples were tested using a rotorless vulcanizer to obtain vulcanization curves. The optimal vulcanization time for each sample was determined from the vulcanization curves. Finally, tread rubber samples were prepared using different molds. The determined vulcanization process parameters were: vulcanization temperature 150℃, pressure 15MPa, and vulcanization time 27 minutes.

[0090] The tread rubber compound formulations prepared in Examples 1-5 and Comparative Examples 1-3 are shown in Table 2 below:

[0091] Table 2. Tread compound formulations corresponding to Examples 1-5 and Comparative Examples 1-3

[0092] Components Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Modified SSBR 70 70 70 70 70 70 96 96 BR 9000 30 30 30 30 30 30 30 30 Silica VN3 70 70 70 70 70 70 70 70 Zinc oxide 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 stearic acid 2 2 2 2 2 2 2 2 Silane coupling agent Si69 7 7 7 7 7 7 7 7 Anti-aging agent 4020 1 1 1 1 1 1 1 1 Accelerator D 2 2 2 2 2 2 2 2 Aromatic oils 26 26 26 26 26 26 - - sulfur 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Accelerator NS 2 2 2 2 2 2 2 2

[0093] As can be seen from Table 2:

[0094] The tread rubbers corresponding to Examples 1-5 and Comparative Examples 1-3 of this invention adopted a basically uniform compounding formula: the formula skeleton of all samples was exactly the same, all containing SSBR (modified or commercially available), BR9000 (butadiene rubber), silica (VN3), zinc oxide, stearic acid, silane coupling agent (Si69), antioxidant (4020), accelerator (D and NS), and sulfur. Except for SSBR and aromatic oil, the proportions of the other components added were exactly the same.

[0095] Specifically:

[0096] Examples 1-5 and Comparative Example 1 (uncapped modification) all used 70 parts of SSBR prepared by the method described in this invention. Comparative Examples 2 and 3, used as controls of commercially available products, used 96 parts of the corresponding commercially available SSBR grades. 26 parts of aromatic oil were added to the formulations of Examples 1 and Comparative Example 1, while the amount of aromatic oil in Comparative Examples 2 and 3 was marked as "-" (i.e., not added).

[0097] In summary, Table 2 shows that, under the premise of keeping the reinforcing system (silica + coupling agent), vulcanization system, and anti-aging system completely consistent, the corresponding tread rubber products can be obtained by simply changing the type of SSBR and adjusting its dosage with the processing oil accordingly.

[0098] Specific embodiments also include tread rubber made from the rubber prepared in Examples 1 to 5 above, as well as tires using the tread rubber and vehicles using the tires.

[0099] In the description of this specification, the references to terms such as "embodiment," "basic embodiment," "preferred embodiment," "other embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0101] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A chain-terminated polyvinylpyridine-modified SSBR, characterized in that: It has the molecular structural formula shown in Formula I: Ⅰ； In Formula I: The value of 'a' makes the molecular mass of styrene structural units account for 12-30% of the total molecular mass; The values ​​of b+c result in butadiene structural units accounting for 70-85% of the total molecular mass; The value of d makes the molecular mass of the vinylpyridine structural unit account for 0.2~3% of the total molecular mass.

2. The modified SSBR according to claim 1, characterized in that: b / (b+c) is between 0.35 and 0.

7.

3. The modified SSBR according to claim 1 or 2, characterized in that: The molecular weight ranges from 270,000 to 400,000, with a molecular weight distribution between 1.10 and 1.

90.

4. A method for preparing chain-terminated polyvinylpyridine-modified SSBR, characterized in that: The steps include the following: S1: Add the solvent to the reactor, then add a regulator and an activator, such that the regulator content is 50~500 ppm and the activator content is 20~600 ppm; then add butadiene monomer and styrene monomer, and the mixed monomer concentration in the reactor is 20~200 kg / m³. 3 The mass fraction of styrene monomer accounts for 12-30% of the mixed monomer content; the temperature inside the polymerization reactor is raised to 40-50℃, and an initiator is added to copolymerize butadiene monomer and styrene monomer; S2: After the copolymerization reaction is completed, vinylpyridine is added to the reactor for end-capping reaction, and the reaction temperature is controlled at -70~30℃; S3: After the end-capping reaction is complete, a terminator is added to terminate the reaction with the active center at the end of the rubber molecular chain. The active center is composed of carbanion and lithium ion. The molar amount of the terminator is 1 to 2 times the molar amount of the active center. S4: The solvent is removed from the adhesive solution after the termination reaction is completed to form adhesive water, and the adhesive water is dehydrated to obtain dry rubber.

5. The preparation method according to claim 4, characterized in that: The regulator is selected from tetrahydrofurfuryl ethyl ether, furfuryl propane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, and triethylamine; The activator is tetrahydrofuran; The initiator is an alkyl lithium, wherein the alkyl group in the alkyl lithium comprises a C2-C10 straight-chain or branched saturated alkane; The solvent is selected from one or two of cyclohexane, n-hexane, cyclopentane, n-heptane, benzene, toluene, and ethylbenzene; The terminating agent is an alcoholic organic compound or a phenolic organic compound.

6. The preparation method according to claim 4 or 5, characterized in that: The materials pass through the first, middle, and final kettles in sequence; The solvent, butadiene monomer, styrene monomer, regulator, activator and initiator are all added from the bottom of the first batch. During the reaction, the material moves upward from the bottom of the reactor and flows out from the top to the bottom of the next reactor; The butadiene monomer and styrene monomer undergo complete copolymerization in the first or second reactor. Vinylpyridine is added from the top of the first vessel, the bottom of the middle vessel, the top of the middle vessel, and the bottom of the last vessel; The terminator is added from the bottom or top of the final vessel; Terminator should not be added simultaneously with vinylpyridine.

7. Tread rubber, characterized in that: The raw materials include the modified SSBR according to any one of claims 1 to 3, or the raw materials include the modified SSBR prepared by the preparation method according to any one of claims 4 to 6.

8. The tread rubber according to claim 7, characterized in that: It includes silica, and the modified SSBR is connected to the silica at least by hydrogen bonds.

9. A tire, characterized in that: The tread rubber described in claim 7 or 8 was used.

10. A vehicle, characterized in that: Use the tire as described in claim 9.

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