Star-shaped styrene-grafted butadiene-isoprene modified rubber, its preparation method and application

Abstract

This invention relates to the field of rubber preparation, and discloses a star-shaped styrene-grafted butadiene-isoprene modified rubber, its preparation method, and its applications. The modified rubber comprises polymeric segments from a coupling agent and multiple styrene homopolymer segments and butadiene-isoprene copolymer segments grafted onto the polymeric segments, wherein the coupling agent is selected from polyvinyl aromatic monomers. Through structural design during polymerization, mixed arms are formed, resulting in a uniform distribution of the polymer structure in the microphase, with mutual synergistic effects. This results in high hardness, good strength, good branching, and physical properties similar to natural rubber, improving the rubber's wet slip resistance and reducing rolling resistance. When used in combination with various synthetic or natural rubbers, it can improve the rigidity, hardness, abrasion resistance, tear resistance, and dielectric properties of rubber products, and is widely used in tires, belts, hoses, rubber shoes, and many other rubber processing fields and industries.

Description

Technical Field

[0001] This invention relates to the field of rubber preparation, specifically to a star-shaped styrene-grafted butadiene-isoprene modified rubber, its preparation method, and its application. Background Technology

[0002] Copolymers composed of isoprene or butadiene and styrene typically contain 23-30% bound styrene. Higher bound styrene content results in copolymers with greater plasticity, while lower bound styrene content leads to greater elasticity. Copolymers with 45-70% bound styrene in their molecular structure are generally called high-styrene rubbers, and those with over 70% bound styrene are called high-styrene resins. Due to the higher bound styrene content, high-styrene rubbers have different physical properties than general-purpose styrene-butadiene rubber (SBR). High-styrene rubber is rarely used alone. When blended with various synthetic or natural rubbers, it can improve the rigidity, hardness, abrasion resistance, tear resistance, and dielectric properties of rubber products. It is widely used in the tire, shoe, printing, and other industries, and is also highly valued for its modification of synthetic plastics.

[0003] Most existing technologies employ latex co-coagulation technology. While this process can yield high-styrene rubber with good performance, its main problems are: First, in terms of process, it requires the separate synthesis of SBR-1500 or SBR-1502 latex and high-styrene resin emulsion. The two qualified emulsions are then mixed in a certain proportion, followed by coagulation and drying to obtain high-styrene rubber. This process is relatively long, requiring two synthesis steps involving the preparation of aqueous and oil phases, initiator, and degassing. Second, in terms of production cost, the monomer conversion rate of synthesized SBR-1500 or SBR-1502 latex is only 70%, with 30% unreacted monomers. These unreacted monomers are difficult to recover in small- to medium-scale production facilities, resulting in high production costs and relatively high equipment, auxiliary materials, personnel, time, and energy requirements for the polymerization reaction. Furthermore, in terms of production cycle, because the synthesis temperature of high-styrene resin emulsion is high-temperature polymerization, there is a large amount of gel in the polymerization reactor. The reactor typically requires cleaning after every 10 batches, resulting in low equipment utilization.

[0004] Although high-styrene rubber can be produced through blending and copolymerization, the polymers used in these processes suffer from drawbacks such as insufficient tensile strength and hardness, poor miscibility with natural rubber and styrene-butadiene rubber, and an inability to achieve both comprehensive rubber performance and improved dynamic mechanical properties. Furthermore, these methods are complex, difficult to implement, have long reaction cycles, high costs, and are prone to gel formation, causing environmental pollution.

[0005] In the existing technology, high-styrene rubber is mainly produced by emulsion polymerization of butadiene and styrene monomers. The high-styrene rubber prepared has poor rolling resistance, wet skid resistance and wear resistance. It is a problem that needs to be solved in this field to balance the comprehensive performance of the rubber and improve its dynamic mechanical properties. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of poor rolling resistance, wet skid resistance and wear resistance of high styrene rubber in the prior art, and to provide a star-shaped styrene-grafted butadiene-isoprene modified rubber, its preparation method and application.

[0007] To achieve the above objectives, a first aspect of the present invention provides a star-shaped styrene-grafted butadiene-isoprene modified rubber, wherein the modified rubber comprises polymeric segments from a coupling agent and a plurality of styrene homopolymer segments and butadiene-isoprene copolymer segments grafted onto the polymeric segments, wherein the coupling agent is selected from polyvinyl aromatic monomers.

[0008] A second aspect of the present invention provides a method for preparing star-shaped styrene-grafted butadiene-isoprene modified rubber, wherein the preparation method includes:

[0009] (1) Styrene undergoes homopolymerization in the presence of an initiator to obtain an active styrene homopolymer segment;

[0010] (2) The active styrene homopolymer segment is coupled with a coupling agent to obtain an active chain;

[0011] (3) In the presence of a polar activator, the active chain, butadiene and isoprene are copolymerized to obtain the star-shaped mixed arm high styrene rubber.

[0012] A third aspect of the present invention provides a star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method described above.

[0013] The fourth aspect of this invention provides the application of the star-shaped styrene-grafted butadiene-isoprene modified rubber and the star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method described above in the field of rubber processing.

[0014] Through the above technical solution, this invention provides a star-shaped styrene-grafted butadiene-isoprene modified rubber. From the perspective of polymer chain structure, it is a branched polymer with a star-shaped structure, meaning that multiple molecular chains are grafted onto the polymeric chain segments to form different chain segments as branches, similar to connected molecular arms (such as polybutadiene-isoprene arms and styrene arms), referred to as mixed arms. In the modified rubber, the polymeric chain segments formed by the coupling agent of polybutadiene-isoprene rubber and polystyrene rubber are used as the core and chained together, realizing the combination of different polymer molecular chains at the short-range structural level of the polymer chain. It can have good compatibility, stability and adhesion, making the polymer structure uniformly distributed in the microphase and coordinating with each other. It has high hardness, good strength, good branching degree and also has the physical properties of natural rubber, improving the rubber's anti-slip properties and reducing rolling resistance. When used in combination with various synthetic or natural rubbers, it can improve the rigidity, hardness, abrasion resistance, tear resistance, and dielectric properties of rubber products, and is widely used in tires, belts, hoses, rubber shoes, and many other rubber processing fields and industries. The method for preparing this star-shaped styrene-grafted butadiene-isoprene modified rubber provided by this invention has the characteristics of simple process, mild polymerization conditions, stable product performance, and good overall performance. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the molecular chain structure of star-shaped styrene-grafted butadiene-isoprene modified rubber.

[0016] Explanation of reference numerals in the attached figures

[0017] PS represents the homopolymer segment of styrene, and PIB represents the copolymer segment of butadiene-isoprene. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] The first aspect of the present invention provides a star-shaped styrene-grafted butadiene-isoprene modified rubber, wherein the modified rubber comprises polymeric segments from a coupling agent and a plurality of styrene homopolymer segments and butadiene-isoprene copolymer segments grafted onto the polymeric segments, wherein the coupling agent is selected from polyvinyl aromatic monomers.

[0020] In this invention, the star-shaped styrene-grafted butadiene-isoprene modified rubber is a branched polymer with a star-shaped structure from the perspective of polymer chain structure. The polymeric segment formed by the coupling agent serves as the core, and the multiple vinyl functional groups of the coupling agent provide multiple vinyl groups for further grafting of other branches onto the polymeric segment. The butadiene-isoprene copolymer chain and the styrene homopolymer chain can be bonded to the vinyl groups on the polymeric segment through their respective carbon-carbon double bonds to form butadiene-isoprene copolymer segments and styrene homopolymer segments grafted onto the polymeric segment. That is, multiple molecular chains are grafted onto the polymeric segment to form different segments as branches, similar to connected molecular arms (such as polybutadiene-isoprene arms and styrene arms), which are called mixed arms. In the modified rubber, the polymer segments formed by the coupling agent of polybutadiene-isoprene rubber and polystyrene rubber are used as the core to link them together, realizing the combination of different polymer molecular chains at the short-range structural level of the polymer chain. It can have good compatibility, stability and adhesion, so that the polymer structure is evenly distributed in the microphase and works in coordination with each other. It has high hardness, good strength, good branching degree and the physical properties of natural rubber, improves the rubber's anti-slip properties and reduces rolling resistance.

[0021] In this invention, the molecular arms of the polymer are connected by polymeric segments from a coupling agent selected from polyvinyl aromatic monomers. These polyvinyl aromatic monomers form polymeric segments with multi-terminal molecular arms through self-polymerization, such as... Figure 1 As shown, multiple linear branches are chemically bonded to the same central core, achieving molecular blending of the polymer. This results in a more uniform distribution of the polymer structure in the microphase, leading to better physical and mechanical properties of the rubber. PS represents styrene homopolymer segments, and PIB represents butadiene-isoprene copolymer segments.

[0022] In some specific embodiments of the present invention, in the modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 30-70 wt%, and the content of the butadiene-isoprene copolymer segments is 30-70 wt%. By limiting the above-mentioned contents, the modified rubber achieves the bonding of different polymer molecular chains at the short-range structural level of the polymer chain, resulting in good compatibility, stability, and adhesion. This ensures that the polymer structure is uniformly distributed in the microphase, with mutual synergistic effects, and exhibits high hardness and good strength.

[0023] In some specific embodiments of the present invention, in the modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments can be selected as 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, or any value within the range of any two of the above values. The content of the butadiene-isoprene copolymer segments can be selected as 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, or any value within the range of any two of the above values.

[0024] In some specific embodiments of the present invention, in the butadiene-isoprene copolymer segment, based on the total weight of the butadiene-isoprene copolymer segment, the content of isoprene structural units is 50-90 wt%, and the content of butadiene structural units is 10-50 wt%.

[0025] In some specific embodiments of the present invention, the content of isoprene structural units in the butadiene-isoprene copolymer segment can be selected from 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, and any value within the range of any two of the above values. The content of butadiene structural units can be selected from 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, and any value within the range of any two of the above values.

[0026] In some specific embodiments of the present invention, in the butadiene-isoprene copolymer segment, based on the total weight of the butadiene-isoprene copolymer segment, the total content of isoprene 1,4-structural units and butadiene 1,4-structural units is 40-80 wt%, and the total content of isoprene 3,4-structural units and butadiene 1,2-structural units is 20-60 wt%.

[0027] In some specific embodiments of the present invention, the total content of the 1,4-structural units of isoprene and the 1,4-structural units of butadiene in the butadiene-isoprene copolymer segment can be selected as 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, or any value within the range of any two of the above values. The total content of the 3,4-structural units of isoprene and the 1,2-structural units of butadiene can be selected as 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, or any value within the range of any two of the above values.

[0028] In some specific embodiments of the present invention, preferably, the coupling agent is selected from divinylbenzene.

[0029] In some specific embodiments of the present invention, the amount of coupling agent used in the modified liquid styrene-butadiene rubber is relatively small. The polymeric segments formed by the coupling agent are used as the core. The core formed by the coupling agent is a macromolecular active species. The macromolecular active species provides the polymer with multiple reactive sites that can further initiate the polymerization of reactive monomers, thereby initiating the polymerization of monomers to form polymeric segments. The proportion of polymeric segments formed by the coupling agent itself is very small relative to the amount of macromolecular polymer, and its content can be excluded from the polymer proportion. The amount of coupling agent used has been described in the text.

[0030] In some specific embodiments of the present invention, the modified rubber has a number-average molecular weight of 100,000-600,000 g / mol and a weight-average molecular weight of 200,000-1,000,000 g / mol; a molecular weight distribution index of 1.2-5, the higher the molecular weight distribution index, the better the processing performance of the rubber, the modified rubber has a molecular weight distribution index of 1.2-5, good processing performance, tanδ(0℃) of 0.22-0.27, tanδ(60℃) of 0.009-0.119, and a coupling efficiency of 60-75%.

[0031] A second aspect of the present invention provides a method for preparing star-shaped styrene-grafted butadiene-isoprene modified rubber, wherein the preparation method includes:

[0032] (1) Styrene undergoes homopolymerization in the presence of an initiator to obtain an active styrene homopolymer segment;

[0033] (2) The active styrene homopolymer segment is coupled with a coupling agent to obtain an active chain;

[0034] (3) In the presence of a polar activator, the active chain, butadiene and isoprene are copolymerized to obtain the star-shaped mixed arm high styrene rubber.

[0035] In some specific embodiments of the present invention, the coupling reaction is that the polymeric segment formed by the coupling agent and the styrene homopolymer segment are bonded to the vinyl group on the polymeric segment through carbon-carbon double bonds, thereby obtaining the active chain.

[0036] In some specific embodiments of the present invention, the initiator is selected from one or more of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium, and dodecyllithium, preferably n-butyllithium and / or sec-butyllithium. The amount of initiator added is determined by the molecular weight of the designed polymer.

[0037] In some specific embodiments of the present invention, the coupling agent is selected from polyvinyl aromatic hydrocarbons, preferably from divinylbenzene. During the coupling reaction, the coupling agent can be added all at once or in multiple additions. Adding the coupling agent multiple times can improve its coupling efficiency.

[0038] In some specific embodiments of the present invention, the polar activator is selected from one or more of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, triethylamine, tetramethylvinyl diamine, and hexamethylphosphonic triamine, preferably selected from one or more of diethylene glycol dimethyl ether, tetrahydrofuran, and tetramethylvinyl diamine. The polymerization system of the present invention requires the addition of a polar organic compound as an activator to induce polarization or solvation of the initiator, reduce its degree of association, and increase the initiation reaction rate of initiators such as n-butyllithium. The activator can also adjust the reactivity ratio between butadiene and isoprene, enabling random copolymerization. Simultaneously, the activator can increase the content of 1,2-structures in the butadiene unit and 3,4-structures in the isoprene unit.

[0039] In some specific embodiments of this invention, the mechanical properties of star-shaped styrene-grafted butadiene-isoprene modified rubber are related to the monomer ratio of styrene, isoprene, and butadiene, as well as the molecular weight of the product. Generally, higher styrene content results in higher hardness and lower elongation at break; higher isoprene and butadiene content results in lower hardness and higher elongation at break. Simultaneously, the molecular weight of the single arm of the high-styrene rubber determines the molecular weight of the product to a certain extent, thus affecting product performance. In this invention, the number-average molecular weight of the single arm of the styrene homopolymer segment is 50,000-150,000 g / mol.

[0040] In some specific embodiments of the present invention, the temperature of the homopolymerization reaction is 50-80°C, the pressure of the homopolymerization reaction is 0.1-0.25 MPa, and the time of the homopolymerization reaction is 20-80 min.

[0041] In some specific embodiments of the present invention, the temperature of the coupling reaction is 50-80°C, the pressure of the coupling reaction is 0.1-0.25 MPa, and the time of the coupling reaction is 60-90 min.

[0042] In some specific embodiments of the present invention, the temperature of the copolymerization reaction is 50-80°C, the pressure of the copolymerization reaction is 0.1-0.25 MPa, and the time of the copolymerization reaction is 60-100 min.

[0043] In some specific embodiments of the present invention, the coupling efficiency of the star-shaped styrene-grafted butadiene-isoprene modified rubber polymer is 61-74%. The coupling efficiency (CE) is determined by GPC analysis of the coupled mixture; the ratio of the peak area of ​​the polymer formed by coupling to the sum of the peak areas of the polymer formed by coupling and the remaining copolymer after coupling is the coupling efficiency. A higher coupling efficiency indicates better coupling performance of divinylbenzene, greater activity of the formed macromolecular active species, and a greater number of linear branches chemically bonded to the central core formed by divinylbenzene.

[0044] In some specific embodiments of the present invention, after the reaction is complete, the obtained polymer solution is treated with water. The amount of water used is generally 100-300 times the amount of initiator, preferably 150-250 times.

[0045] In some specific embodiments of the present invention, 0.5%-1% of an antioxidant by weight of the polymer can be added to the obtained star-shaped styrene-grafted butadiene-isoprene modified rubber, and then the rubber is washed, dehydrated and dried to obtain a high-performance star-shaped styrene-grafted butadiene-isoprene modified rubber.

[0046] In some specific embodiments of the present invention, styrene is 30-70 parts by weight, and the butadiene and isoprene mixed monomer is 30-70 parts by weight, wherein butadiene accounts for 10-50 wt% of the mixed monomer and isoprene accounts for 50-90 wt% of the mixed monomer.

[0047] In some specific embodiments of the present invention, the initiator is 0.0005-0.002 parts by weight.

[0048] In some specific embodiments of the present invention, the molar ratio of the polar activator to the initiator is 0.1-30:1.

[0049] In some specific embodiments of the present invention, the molar ratio of the coupling agent to the initiator is 0.1-1.5:1.

[0050] In some specific embodiments of the present invention, preferably, the styrene monomer is 30-70 parts by weight, and the mixed monomer of butadiene and isoprene is 30-70 parts by weight, wherein butadiene accounts for 10-50 wt% of the mixed monomer and isoprene accounts for 50-90 wt% of the mixed monomer.

[0051] In some specific embodiments of the present invention, preferably, the initiator is 0.0007-0.002 parts by weight.

[0052] In some specific embodiments of the present invention, preferably, the molar ratio of the polar activator to the initiator is 0.2-20:1.

[0053] In some specific embodiments of the present invention, preferably, the molar ratio of the coupling agent to the initiator is 0.15-1:1.

[0054] In this invention, the composition and structure of the modified rubber can be determined by nuclear magnetic resonance, infrared spectroscopy, GPC, elemental analysis, etc., or by preparation and feeding. The total content of 1,4-structural units of isoprene and 1,4-structural units of butadiene, as well as the total content of 3,4-structural units of isoprene and 1,2-structural units of butadiene, are determined by infrared spectroscopy.

[0055] A third aspect of this invention provides a star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method described above. It may have the aforementioned compositional and structural characteristics, which will not be repeated here.

[0056] The fourth aspect of this invention provides the application of the star-shaped styrene-grafted butadiene-isoprene modified rubber and the star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method described above in the field of rubber processing.

[0057] The present invention will be described in detail below through embodiments.

[0058] 1,3-Butadiene (polymer grade) produced by Lanzhou Petrochemical Company of PetroChina; isoprene (polymer grade) produced by Shanghai Petrochemical Company of PetroChina; cyclohexane (polymer grade) produced by Lanzhou Petrochemical Company of PetroChina; n-Butyllithium (98% purity) provided by Fushun Petrochemical Company of PetroChina; tetrahydrofuran (THF) (analytical grade) provided by Nanjing Tonglian Chemical Co., Ltd.

[0059] Diethylene glycol dimethyl ether (2G) analytical grade, produced by Sinopharm Chemical Reagent Co., Ltd.; Tetramethylvinyldiamine (TMEDA) analytical grade, produced by Beijing Daxing Xingfu Chemical Research Institute; Divinylbenzene (DVB) analytical grade, produced by Shanghai Oule Chemical Co., Ltd.

[0060] Antioxidant 1010 (pentaerythritol tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) ester) is manufactured by BASF Chemicals.

[0061] Antioxidant 1076 (3,5-diter-butyl-4-hydroxyphenylpropionate octadecyl ester), manufactured by BASF Chemical Company.

[0062] Determination of molecular weight and coupling efficiency: The molecular weight and distribution of the sample were analyzed using a Viscoteck TDA302 gel permeation chromatography (GPC) instrument manufactured by Agilent Technologies, USA, with THF as the mobile phase and a test temperature of 30℃.

[0063] Fourier transform infrared spectroscopy (FTIR) analysis: Analysis was performed using a Nicolet 560 FTIR instrument (USA). No purification was required; potassium bromide pellets were used for coating. This method was used to determine the styrene, butadiene, and isoprene content in modified rubber.

[0064] Dynamic mechanical analysis (DMA): The dynamic mechanical properties of the specimens were tested using a Va3000 dynamic thermomechanical analyzer manufactured by 01db-Metravib, France, under shear-type conditions and a deformation amplitude of 5%.

[0065] Mechanical property analysis: The mechanical properties of the specimens were tested using a 5567 universal testing machine manufactured by Instron Corporation, USA.

[0066] Mooney viscosity determination: The Mooney viscosity was measured using an MV2000 Mooney viscometer from Alpha Corporation, USA, in accordance with GB / T 1232.1-2000.

[0067] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products. The composition and structure of the modified rubbers described in the following examples and comparative examples can be determined by NMR, IR, GPC, elemental analysis, or by the preparation and feeding process.

[0068] Example 1

[0069] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added to continue coupling. After reacting for 60 min, a mixture of 2.11g of tetrahydrofuran, 4212g of cyclohexane, 234g of butadiene, and 234g of isoprene was injected into the polymerization reactor, and the reaction was continued for another 60 min. After the reaction was completed, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The adhesive solution is wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 50 wt%, and the content of the butadiene-isoprene copolymer segments is 50 wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units is 50 wt%, and the content of the butadiene structural units is 50 wt%).

[0070] Example 2

[0071] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene (50wt% of the total monomers), and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added to continue coupling. After reacting for 60 min, a mixture of 0.339g of tetramethylvinyldiamine, 4212g of cyclohexane, 234g of butadiene (50wt% of the mixed monomers), and 234g of isoprene (50wt% of the mixed monomers) was added to the polymerization reactor, and the reaction was continued for another 60 min. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The adhesive solution is wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 50 wt%, and the content of the butadiene-isoprene copolymer segments is 50 wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units is 50 wt%, and the content of the butadiene structural units is 50 wt%).

[0072] Example 3

[0073] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added to continue coupling. After reacting for 60 min, a mixture of 0.392g of diethylene glycol dimethyl ether (2g), 4212g of cyclohexane, and 234g of butadiene and 234g of isoprene was added to the polymerization reactor, and the reaction was continued for another 60 min. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g of water was added. Add 10g of antioxidant 1076 and 5g of antioxidant 1010, stir evenly, and the adhesive solution is wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and butadiene-isoprene copolymer segments, the content of styrene homopolymer segments is 50wt%, and the content of butadiene-isoprene copolymer segments is 50wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of isoprene structural units is 50wt%, and the content of butadiene structural units is 50wt%).

[0074] Example 4

[0075] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added in two portions (70wt% of the total divinylbenzene was added in the first portion, and the remaining 30wt% was added after 30 min of reaction) for coupling reaction. After 80 min of reaction, a mixture of 2.11g of tetrahydrofuran, 4212g of cyclohexane, 234g of butadiene, and 234g of isoprene was injected into the polymerization reactor, and the reaction was continued for 60 min. After the reaction was completed, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The adhesive solution is wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 50 wt%, and the content of the butadiene-isoprene copolymer segments is 50 wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units is 50 wt%, and the content of the butadiene structural units is 50 wt%).

[0076] Example 5

[0077] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 4.68mmol of divinylbenzene was added in two portions (70wt% of the total divinylbenzene was added in the first portion, and the remaining 30wt% was added after 30 min of reaction) for coupling reaction. After 80 min of reaction, a mixture of 2.11g of tetrahydrofuran, 4212g of cyclohexane, 234g of butadiene, and 234g of isoprene was injected into the polymerization reactor, and the reaction was continued for 60 min. After the reaction was completed, the coupling was treated with water. The reaction mixture was then mixed with 100g of water, 10g of antioxidant 1076, and 5g of antioxidant 1010. The mixture was stirred until homogeneous, and the solution was then wet-coagulated and dried to obtain modified rubber. (In the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments was 50wt%, and the content of the butadiene-isoprene copolymer segments was 50wt%. In the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units was 50wt%, and the content of the butadiene structural units was 50wt%.)

[0078] Example 6

[0079] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 11.70mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added in two portions (70wt% of the total divinylbenzene was added in the first portion, and the remaining 30wt% was added after 30min of reaction) for coupling reaction. After 80min of reaction, a mixture of 4.22g of tetrahydrofuran, 4212g of cyclohexane, 234g of butadiene, and 234g of isoprene was forced into the polymerization reactor, and the reaction was continued for 60min. After the reaction was completed, the coupling was treated with water. After mixing, add 100g of water, 10g of antioxidant 1076, and 5g of antioxidant 1010 to the reaction mixture, stir until homogeneous, and then wet-coagulate and dry to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 50wt%, and the content of the butadiene-isoprene copolymer segments is 50wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units is 50wt%, and the content of the butadiene structural units is 50wt%).

[0080] Example 7

[0081] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 5054g of cyclohexane, 562g of styrene, and 7.03mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.81mmol of divinylbenzene was added in two portions (70wt% of the total divinylbenzene was added in the first portion, and the remaining 30wt% was added after 30 min of reaction) for coupling reaction. After 80 min of reaction, a mixture of 2.54g of tetrahydrofuran, 3370g of cyclohexane, and 187g of butadiene and 187g of isoprene was injected into the polymerization reactor, and the reaction was continued for 60 min. After the reaction was completed, the coupling was treated with water. The reaction mixture was then mixed with 100g of water, 10g of antioxidant 1076, and 5g of antioxidant 1010. The mixture was stirred until homogeneous, and the solution was then wet-coagulated and dried to obtain modified rubber. (In the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments was 60wt%, and the content of the butadiene-isoprene copolymer segments was 40wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units was 50wt%, and the content of the butadiene structural units was 50wt%.)

[0082] Example 8

[0083] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 5475g of cyclohexane, 608g of styrene, and 7.60mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80min. After complete monomer conversion, the temperature was raised to 80℃, and 3.04mmol of divinylbenzene was added in two portions (70wt% of the total divinylbenzene was added in the first portion, and the remaining 30wt% was added after 30min of reaction) for coupling reaction. After 80min of reaction, a mixture of 2.74g of tetrahydrofuran, 2949g of cyclohexane, 131g of butadiene, and 196g of isoprene was injected into the polymerization reactor, and the reaction was continued for 60min. After the reaction was completed, the coupling was treated with water. The reaction mixture was then mixed with 100g of water, 10g of antioxidant 1076, and 5g of antioxidant 1010. The mixture was stirred until homogeneous, and the solution was then wet-coagulated and dried to obtain modified rubber. (In the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments was 65wt%, and the content of the butadiene-isoprene copolymer segments was 35wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units was 40wt%, and the content of the butadiene structural units was 60wt%).

[0084] Example 9

[0085] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 468g of styrene, and 5.85mmol of n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80 min. After complete monomer conversion, the temperature was raised to 80℃, and 2.34mmol of divinylbenzene was added in three portions (50wt% of the total divinylbenzene was added first, 30wt% was added after 15 min, and the remaining 20wt% was added after 30 min) for coupling reaction. After reacting for 80 min, a mixture of 0.39g of diethylene glycol dimethyl ether (2G), 4212g of cyclohexane, 234g of butadiene, and 234g of isoprene was forced into the polymerization reactor, and the reaction was continued for 60 min. After completion, the coupled reaction mixture was treated with water, 100g of water, 10g of antioxidant 1076, and 5g of antioxidant 1010 were added and stirred evenly. The solution was then wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments was 50wt%, and the content of the butadiene-isoprene copolymer segments was 50wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units was 50wt%, and the content of the butadiene structural units was 50wt%).

[0086] Example 10

[0087] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g pentane, 468g styrene, and 5.85mmol n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 60min. After complete monomer conversion, 2.34mmol divinylbenzene was added in two portions (50wt% of the total divinylbenzene was added in the first portion, and the remaining 50wt% was added after 30min of reaction) for coupling reaction. After 80min of reaction, a mixture of 2.11g tetrahydrofuran, 4212g pentane, 234g butadiene, and 234g isoprene was injected into the polymerization reactor, and the reaction was continued for another 60min. After the reaction was completed, the coupling was treated with water. After mixing, 100g of water and 15g of antioxidant 1010 were added to the reaction mixture, and the mixture was stirred evenly. The adhesive solution was then wet-coagulated and dried to obtain modified rubber (in the obtained modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments was 50wt%, and the content of the butadiene-isoprene copolymer segments was 50wt%; in the butadiene-isoprene copolymer segments, based on the total weight of the butadiene-isoprene copolymer segments, the content of the isoprene structural units was 50wt%, and the content of the butadiene structural units was 50wt%).

[0088] Comparative Example 1

[0089] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 8424g cyclohexane, 468g styrene (50wt% of total monomers), 234g butadiene (25wt% of total monomers), 234g isoprene (25wt% of total monomers), and 4.21g tetrahydrofuran were added to the polymerization reactor. 11.70mmol of n-butyllithium was added, and the temperature was raised to 50℃. Polymerization was carried out for 80min. After complete monomer conversion, the temperature was raised to 80℃, and the reaction continued until no free monomers remained. 2.93mmol of SnCl4 coupling agent was added for coupling. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g water and 12g antioxidant 1010 were added, followed by stirring. The resulting solution was then wet-coagulated and dried.

[0090] Comparative Example 2

[0091] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 234g of styrene (25wt% of total monomers), and 234g of butadiene (25wt% of total monomers) were added to the polymerization reactor, along with 11.70mmol of n-butyllithium. Polymerization was carried out for 80 minutes. Then, a mixture of 0.679g of tetramethylvinyldiamine, 4212g of cyclohexane, 234g of styrene (25wt% of total monomers), and 234g of butadiene (25wt% of total monomers) was injected into the polymerization reactor and the reaction continued for another 60 minutes. After complete monomer conversion, 2.93mmol of SnCl4 coupling agent was added for coupling. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The resulting gel was then wet-coagulated and dried.

[0092] Comparative Example 3

[0093] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g of cyclohexane, 234g of styrene (25wt% of total monomers), and 234g of isoprene (25wt% of total monomers) were added to the polymerization reactor, along with 11.70mmol of n-butyllithium. Polymerization was carried out for 80 minutes. Then, a mixture of 0.784g of diethylene glycol dimethyl ether, 4212g of cyclohexane, 234g of styrene (25wt% of total monomers), and 234g of isoprene (25wt% of total monomers) was forced into the polymerization reactor and the reaction continued for another 60 minutes. After complete monomer conversion, 2.93mmol of SnCl4 coupling agent was added for coupling. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The gel was then wet-coagulated and dried.

[0094] Comparative Example 4

[0095] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 8424g cyclohexane, 468g styrene (50wt% of total monomers), 234g butadiene (25wt% of total monomers), 234g isoprene (25wt% of total monomers), 4.21g tetrahydrofuran, and 11.70mmol n-butyllithium were added to the polymerization reactor. The temperature was raised to 50℃, and polymerization was carried out for 80min. After complete monomer conversion, the temperature was raised to 80℃, and the reaction continued until no free monomers remained in the polymerization reaction. Then, 2.93mmol SnCl4 was added in two batches (80wt% of total SnCl4 added initially, and the remaining 20wt% added after 30min of reaction) for coupling reaction. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g water and 12g antioxidant 1010 were added, followed by stirring. The gel was then wet-coagulated and dried.

[0096] Comparative Example 5

[0097] The commercially available high-styrene rubber HS860 uses styrene and butadiene as raw materials for polymerization. The difference lies in the polymerization method. First, high-styrene resin (styrene / butadiene = 80 / 20) is prepared by emulsion polymerization, and then it is blended with emulsion-polymerized styrene-butadiene rubber (styrene / butadiene = 23 / 77) to finally obtain high-styrene rubber.

[0098] Comparative Example 6

[0099] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 5054g of cyclohexane and 562g of styrene (60wt% of the total monomers) were added to the polymerization reactor, along with 11.70mmol of n-butyllithium. The temperature was raised to 50°C, and polymerization was carried out for 80 minutes. After complete monomer conversion, the temperature was raised to 80°C, and a mixture of 4.21g of tetrahydrofuran, 1685g of cyclohexane, and 187g of isoprene (20wt% of the total monomers) was added to the polymerization reactor. The reaction was continued for another 60 minutes. After complete monomer conversion, 1685g of cyclohexane and 187g of butadiene (20wt% of the total monomers) were added to the polymerization reactor. After complete reaction, 2.93mmol of SnCl4 coupling agent was added for coupling. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g of water and 12g of antioxidant 1010 were added, followed by stirring. The gel was then wet-coagulated and dried.

[0100] Comparative Example 7

[0101] In a jacketed 15L stainless steel reactor, the system was purged three times with argon gas. 4212g cyclohexane, 468g styrene (50wt% of total monomers), 234g butadiene (25wt% of total monomers), 234g isoprene (25wt% of total monomers), and 4.21g tetrahydrofuran were added to the polymerization reactor. 11.70mmol of n-butyllithium was added, and the temperature was raised to 50℃. Polymerization was carried out for 80min. After complete monomer conversion, the temperature was raised to 80℃, and the reaction continued until no free monomers remained in the polymerization reaction. 2.93mmol of divinylbenzene was added for coupling. After the reaction was complete, the coupled reaction mixture was treated with water, and 100g water and 12g antioxidant 1010 were added, followed by stirring. The resulting gel was then wet-coagulated and dried.

[0102] The high-styrene rubbers obtained according to the methods of Examples 1-10 and Comparative Examples 1-7, and the molecular weight and microstructure content of the rubbers are shown in Table 1. (Ip-1,4 and Ip-3,4 represent the 1,4- and 3,4-structures of isoprene, respectively; Bd-1,4 and Bd-1,2 represent the 1,4- and 1,2-structures of butadiene, respectively.) Table 1 Table 1 (continued)

[0103]

[0104]

[0105] Table 1 (continued)

[0106]

[0107] Table 1 shows that the polar activators tetrahydrofuran, diethylene glycol dimethyl ether, and tetramethylvinyldiamine can increase the content of the 1,2-structure in butadiene units and the 3,4-structure in isoprene units. The examples demonstrate that the ability of the polar activators to regulate the 1,2-structure in butadiene units and the 3,4-structure in isoprene units is greater with tetramethylvinyldiamine than with diethylene glycol dimethyl ether, which in turn is greater with tetrahydrofuran.

[0108] The liquid rubbers obtained according to the methods of Examples 1-10 and Comparative Examples 1-7 were tested, and the results are shown in Table 2.

[0109] Table 2

[0110] Styrene content / % 50 50 50 50 Tensile strength / MPa 21.54 20.73 20.92 23.27 Elongation at break / % 345 368 379 371 Hardness (Shore A) 91 93 91 92 Mooney viscosity 84 82 81 86 Permanent deformation / % 11 10 11 10 tanδ(0℃) 0.251 0.234 0.261 0.248 tanδ(60℃) 0.009 0.101 0.102 0.111 Coupling efficiency CE (%) 63 63 64 72

[0111] Table 2 (continued)

[0112]

[0113]

[0114] Table 2 (continued)

[0115] Styrene content / % 50 50 50 50 Tensile strength / MPa 20.91 19.92 18.3 21.1 Elongation at break / % 361 354 335 313 Hardness (Shore A) 84 79 75 78 Mooney viscosity 79 77 63 70 Permanent deformation / % 10 13 13 14 tanδ(0℃) 0.241 0.227 0.181 0.192 tanδ(60℃) 0.108 0.119 0.121 0.124 Coupling efficiency CE (%) 66 64 52 53

[0116] Table 2 (continued)

[0117] Styrene content / % 25 50 60 60 50 Tensile strength / MPa 20.5 17.2 20.5 19.3 18.9 Elongation at break / % 292 367 190 192 336 Hardness (Shore A) 81 76 81 73 76 Mooney viscosity 78 67 68 70 64 Permanent deformation / % 12 13 — — 13 tanδ(0℃) 0.201 0.193 — — 0.186 tanδ(60℃) 0.129 0.125 — — 0.123 Coupling efficiency CE (%) 53 54 — 48 55

[0118] As shown in Table 2, in the synthesis of star-shaped styrene-grafted butadiene-isoprene modified rubber, the method of secondary feeding (addition of styrene homopolymer monomer segments and addition of butadiene-isoprene copolymer monomer segments) synthesizes star-shaped styrene-grafted butadiene-isoprene modified rubber with mixed arms (such as polystyrene arms and butadiene-isoprene copolymer arms) and different contents of 1,2-structure in butadiene units and 3,4-structure in isoprene units. Due to the presence of mixed arms, it is equivalent to chaining styrene homopolymer segments and butadiene-isoprene copolymer segments with different microstructures onto the same molecular chain, realizing the blending of polymers at the molecular structure level, improving the rubber and its vulcanization performance, promoting the synergistic optimization of various product properties, and improving the product's hardness and dynamic mechanical properties. The isoprene structural units in the polymer are very similar to those in natural rubber, giving the product properties and applications closer to those of natural rubber. In applications, it can be better mixed with natural rubber and styrene-butadiene rubber, significantly improving compatibility and reducing phase separation in the blend. Furthermore, through structural design during polymerization, mixing arms are formed, linking styrene homopolymer segments and butadiene-isoprene copolymer segments with different microstructures onto the same molecular chain. This achieves molecular-level blending of the polymer, resulting in a uniform distribution of the polymer structure in the microphase and synergistic effects. This avoids the disadvantages of uneven distribution, poor product quality and performance, and high energy consumption that occur when star-shaped styrene-grafted butadiene-isoprene modified rubber is mechanically mixed with natural rubber. The star-shaped high-styrene rubber of this invention has high hardness and good strength. The polymer formed has a high degree of branching and also has the physical properties of natural rubber. It realizes the blending of polymers at the molecular structure level. When used in combination with various synthetic rubbers or natural rubbers, it can improve the rigidity, hardness, wear resistance, tear resistance, dielectric properties and other properties of rubber products. It is widely used in many rubber processing fields such as tires, belts, hoses, and rubber shoes, as well as other industries.

[0119] The method for preparing the star-shaped styrene-grafted butadiene-isoprene modified rubber provided by this invention has the advantages of simple process, mild polymerization conditions, high coupling efficiency, stable product performance, and good comprehensive performance. Furthermore, a larger tanδ / 0℃ value indicates better wet skid resistance of the rubber, while a smaller tanδ / 60℃ value indicates lower rolling resistance. As shown in Table 2, the tanδ / 0℃ values ​​of the rubbers in the embodiments of this application are all better than those in the comparative examples, indicating better wet skid resistance. The tanδ / 60℃ values ​​of the rubbers in the embodiments are all smaller than those in the comparative examples, indicating lower rolling resistance. Among them, Examples 1, 3, and 5 show better wet skid resistance and rolling resistance.

[0120] As shown in Table 2, the coupling efficiency of the examples is higher than that of the comparative example, indicating that the better the coupling performance of divinylbenzene, the greater the activity of the formed macromolecular active species, the more linear branches are chemically bonded to the central core formed by divinylbenzene, and the higher the branching degree of the star polymer formed. Table 2 also shows that the performance of the examples is superior to that of the comparative example in several aspects. The tensile strength and elongation at break of the examples are higher than those of the comparative example, the hardness of the examples is relatively higher, the Mooney viscosity of the examples is slightly better, and the permanent deformation of the examples is slightly lower than that of the comparative example. Therefore, it can be seen that the synthesized star-shaped styrene-grafted butadiene-isoprene modified rubber has excellent dynamic mechanical properties.

[0121] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A star-shaped styrene-grafted butadiene-isoprene modified rubber, characterized in that, The modified rubber comprises polymeric segments from a coupling agent and a plurality of styrene homopolymer segments and butadiene-isoprene copolymer segments grafted onto the polymeric segments, wherein the coupling agent is selected from polyvinyl aromatic monomers; In the modified rubber, based on the sum of the weights of the styrene homopolymer segments and the butadiene-isoprene copolymer segments, the content of the styrene homopolymer segments is 40-70 wt%, and the content of the butadiene-isoprene copolymer segments is 30-60 wt%. In the butadiene-isoprene copolymer segment, based on the total weight of the butadiene-isoprene copolymer segment, the content of isoprene structural units is 50-90 wt%, and the content of butadiene structural units is 10-50 wt%. In the butadiene-isoprene copolymer segment, based on the total weight of the butadiene-isoprene copolymer segment, the total content of isoprene 1,4-structural units and butadiene 1,4-structural units is 40-80 wt%, and the total content of isoprene 3,4-structural units and butadiene 1,2-structural units is 20-60 wt%. The modified rubber has a number-average molecular weight of 100,000-600,000 g / mol, a weight-average molecular weight of 200,000-1,000,000 g / mol, and a molecular weight distribution index of 1.2-5.

2. The modified rubber according to claim 1, wherein, The coupling agent is selected from divinylbenzene.

3. The modified rubber according to claim 1, wherein, The modified rubber has a tanδ of 0.22-0.27 at 0℃ and a tanδ of 0.009-0.119 at 60℃, with a coupling efficiency of 60-75%.

4. A method for preparing the star-shaped styrene-grafted butadiene-isoprene modified rubber according to any one of claims 1-3, characterized in that, The preparation method includes: (1) In the presence of an initiator, styrene undergoes a homopolymerization reaction to obtain an active styrene homopolymer segment; (2) The active styrene homopolymer segment is coupled with a coupling agent to obtain an active chain; (3) In the presence of a polar activator, the active chain, butadiene and isoprene are copolymerized to obtain the star-shaped styrene-grafted butadiene-isoprene modified rubber. Wherein, the styrene is 40-70 parts by weight, and the butadiene and isoprene mixed monomers are 30-60 parts by weight; The polar activator is selected from one or more of diethylene glycol dimethyl ether, tetrahydrofuran, and tetramethylvinyldiamine; Wherein, butadiene accounts for 10-50 wt% of the mixed monomers of butadiene and isoprene, and isoprene accounts for 50-90 wt% of the mixed monomers of butadiene and isoprene. The coupling agent is selected from polyvinyl aromatic hydrocarbon monomers.

5. The preparation method according to claim 4, wherein, The initiator is selected from one or more of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium.

6. The preparation method according to claim 5, wherein, The initiator is selected from n-butyllithium and / or sec-butyllithium.

7. The preparation method according to claim 5, wherein, The coupling agent is selected from divinylbenzene.

8. The preparation method according to claim 5, wherein, During the coupling reaction, the coupling agent may be added once or multiple times.

9. The preparation method according to claim 4, wherein, The homopolymerization reaction is carried out at a temperature of 50-80℃, a pressure of 0.1-0.25MPa, and a time of 20-80min.

10. The preparation method according to claim 9, wherein, The coupling reaction is carried out at a temperature of 50-80℃, a pressure of 0.1-0.25MPa, and a time of 60-90min.

11. The preparation method according to claim 9, wherein, The copolymerization reaction is carried out at a temperature of 50-80℃, a pressure of 0.1-0.25MPa, and a time of 60-100min.

12. The preparation method according to claim 9, wherein, The coupling efficiency of the star-shaped styrene-grafted butadiene-isoprene modified rubber is 61-74%.

13. The preparation method according to claim 4, wherein, The initiator is 0.0005-0.002 parts by weight.

14. The preparation method according to claim 4, wherein, The molar ratio of the polar activator to the initiator is 0.1-30:

1.

15. The preparation method according to claim 4, wherein, The molar ratio of the coupling agent to the initiator is 0.1-1.5:

1.

16. The preparation method according to claim 4, wherein, The styrene monomer is 50-70 parts by weight, and the mixed monomers of butadiene and isoprene are 30-50 parts by weight, wherein butadiene accounts for 30-50 wt% of the mixed monomers and isoprene accounts for 50-70 wt% of the mixed monomers.

17. The preparation method according to claim 16, wherein, The initiator is 0.0007-0.002 parts by weight.

18. The preparation method according to claim 16, wherein, The molar ratio of the polar activator to the initiator is 0.2-20:

1.

19. The preparation method according to claim 16, wherein, The molar ratio of the coupling agent to the initiator is 0.15-1:

1.

20. A star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method according to any one of claims 4-19.

21. The application of the star-shaped styrene-grafted butadiene-isoprene modified rubber according to any one of claims 1-3 or the star-shaped styrene-grafted butadiene-isoprene modified rubber obtained by the preparation method according to any one of claims 4-19 in the field of rubber processing.

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