Capped, modified solution-styrene butadiene rubber and preparation method therefor

Abstract

The present application relates to a capped, modified solution-styrene butadiene rubber and a preparation method therefor. The method comprises: in a multi-tank continuous reaction process, mixing styrene and butadiene in a solvent, then mixing with a structure modifier and an initiator to copolymerize styrene and butadiene to obtain an intermediate polymer; and performing a capping reaction with a capping monomer to obtain a capped polymer; then reacting with a modifier to obtain a modified polymer; and finally mixing with a terminator to obtain a capped, modified solution-styrene butadiene rubber. Thus, the problem of poor filler dispersibility is improved, which can stabilize the polymer molecular structure and effectively improve the processing performance of a product.

Description

A kind of end-capped modified solution-polymerized styrene-butadiene rubber and preparation method thereof

[0001] Cross-reference information

[0002] This application claims priority to the Chinese patent application filed with the Patent Office of China on December 29, 2023, with application number 202311842363.5 and invention name “A kind of end-capped modified solution-polymerized styrene-butadiene rubber and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of synthetic rubber, and in particular to a capped modified solution-polymerized styrene-butadiene rubber and a preparation method thereof. Background Art

[0004] Solution styrene butadiene rubber (SSBR) exhibits excellent low-temperature flexibility, resilience, and wear resistance. Demand for SSBR continues to grow in tires, retreaded and molded products, injection molded and extruded products, medical devices, footwear, and automotive parts. In recent years, SSBR has become the preferred choice for manufacturing high-performance tires, including green tires, anti-skid tires, ultra-lightweight tires, and energy-saving tires, due to its wear and cold resistance, low heat buildup, good shrinkage, excellent color, low ash content, high purity, and fast vulcanization speed. Furthermore, it offers low rolling resistance, excellent wet skid resistance, and excellent wear resistance.

[0005] SSBR is based on butadiene (CH2=CH-CH=CH2) and styrene (C6H5-CH=CH2) as the main monomers. The polymerization of the monomers is initiated by adding organic lithium to a hydrocarbon solvent. After sufficient reaction, antioxidants and other additives are added. The desired sample is obtained through processes such as coagulation and drying.

[0006] Linear SSBR, primarily used in tire manufacturing, is produced primarily through continuous polymerization. Its advantages include stable, uniform product performance, high purity, and extremely low gel content, resulting in high production efficiency and low costs. This makes it suitable for mass production of general-purpose grades. However, with the upgrading of processing equipment and improvements in processing capabilities, higher requirements are being placed on mechanical properties such as Mooney viscosity of SSBR. SSBR molecular weight, Mooney viscosity, and mechanical properties are positively correlated to a certain extent: increasing polymer molecular weight leads to increasing Mooney viscosity and, consequently, improved mechanical properties. However, this increase in Mooney viscosity is often accompanied by a decrease in processing performance.

[0007] Summary of the Invention

[0008] The present application provides a capped modified solution-polymerized styrene-butadiene rubber and a preparation method thereof, in order to improve the reduction in processing performance caused by the increase in Mooney viscosity.

[0009] In a first aspect, the present application provides a method for preparing a modified solution-polymerized styrene-butadiene rubber, the method comprising:

[0010] In a multi-reactor continuous reaction process, styrene and butadiene are mixed in a solvent, and then mixed with a structure regulator and an initiator to allow the styrene and butadiene to undergo a continuous copolymerization reaction to obtain an intermediate polymer;

[0011] Mixing the intermediate polymer and the end-capping monomer to perform an end-capping reaction to obtain an end-capped polymer;

[0012] mixing the end-capped polymer and a modifier to carry out a modification reaction to obtain a modified polymer;

[0013] Mixing the modified polymer and the terminator to obtain end-capped modified solution-polymerized styrene-butadiene rubber;

[0014] The end-capping monomer has a conjugated double bond; the modifier includes a multi-arm modifier, and the multi-arm modifier has at least two arm structures; the added weight of the end-capping monomer is 0.5% to 5% of the total weight of the styrene and butadiene.

[0015] In the prior art, unlike the batch polymerization process in which the amount of material added each time is fixed and in a relatively static space, the material is in a continuous flow state during the continuous polymerization process. The end-capping reaction is already at the end of the polymerization reaction, generating a high-molecular-weight glue. Due to its viscous properties, the added end-capping material is easily wrapped in it, and the flow process is in a laminar form. The reaction only occurs on a few active chains nearby, and the effect of sufficient reaction on each active chain cannot be achieved in batch polymerization.

[0016] The present invention adopts a continuous polymerization process to produce solution-polymerized styrene-butadiene rubber, combines the addition of multiple injection points and a tubular reactor on the continuous polymerization reaction path, changes the laminar flow state of the end-capping material in the flow process of the viscous rubber liquid to a turbulent flow state, strengthens the mixing effect of the viscous rubber liquid and the end-capping material, and enables the end-capping material to fully react with the active chain.

[0017] As an optional embodiment, the end-capping monomer includes a conjugated olefin compound.

[0018] This application uses conjugated olefins as end-capping monomers. Since the conjugated olefins are added to the ends of the active chains and participate in the reaction by opening a double bond, the active chains of the resulting products are still reactive and can continue subsequent reactions.

[0019] In the present application, the active chain ends of the polymer molecules after end-capping are conjugated olefins. Since conjugated olefins have better flexibility than styrene units, they are easy to participate in the reaction during the processing, making the filler uniformly dispersed.

[0020] As an optional embodiment, the conjugated olefin compound includes at least one of butadiene, pentadiene and isoprene.

[0021] As an optional embodiment, the added weight of the end-capping monomer is 2% to 3% of the total weight of the styrene and butadiene.

[0022] In the present invention, by controlling the added weight of the end-capping monomer, the structure of the solution-polymerized styrene-butadiene rubber product can be controlled, which is beneficial to the random distribution of the solution-polymerized styrene-butadiene rubber product and avoids the formation of butadiene block structures at the molecular chain ends of the solution-polymerized styrene-butadiene rubber product caused by excessive addition of the end-capping monomer, thereby being detrimental to the random distribution of the solution-polymerized styrene-butadiene rubber product.

[0023] As an optional embodiment, the multi-arm modifier includes a two-arm modifier and a three-arm modifier.

[0024] In the present invention, the styrene-butadiene rubber prepared by modifying the end-capped intermediate polymer has a branched structure. This branched structure primarily refers to the fact that after the addition of the three-arm modifier, due to steric hindrance, not every theoretically reactive arm can be connected to an active chain. The collision probability results in the actual product being a mixture of two- and three-long-chain products.

[0025] As an optional embodiment, the two-arm modifier includes a halide containing a two-arm structure; and / or

[0026] The three-arm modifier includes siloxane containing a three-arm structure.

[0027] As an optional embodiment, the halide containing a double-arm structure includes diphenyldichlorosilane (diphenyldichlorosilane).

[0028] As an optional embodiment, the multi-arm modifier includes siloxane containing a multi-arm structure.

[0029] As an optional embodiment, the siloxane group includes at least one of an amino group, a methoxy group, a carboxyl group, a thiol group and a hydroxyl group; and / or

[0030] The siloxane includes at least one of 3-chloropropyltrimethoxysilane, 3-chloropropyldimethoxymethylsilane and N-[3-(triethoxysilyl)propyl]-4,5-dihydroimidazole.

[0031] As an optional embodiment, the molar ratio of the modifier to the initiator is (1.5-70):100.

[0032] As an optional embodiment, when the number of arm structures of the multi-arm modifier is no more than 3, the molar ratio of the modifier to the initiator is (15-70):100.

[0033] In the continuous production process of anionic polymerization, theoretically, the active chain can continue to grow under the condition of unlimited monomer amount. However, considering the fluid viscosity of the production process, ultra-high molecular weight linear molecules are entangled with each other, which is not conducive to multi-reactor transportation.

[0034] To solve this type of problem, the present invention chooses to add a multi-arm modifier. Among them, the role of the two-arm modifier is: by adding the two-arm modifier at the end of the continuous polymerization reaction, the desired linear macromolecules can be obtained (which can be understood as doubling the basic molecular weight), which is beneficial to production stability and reducing system risks. The role of the three-arm modifier is: by adding the three-arm siloxane modifier at the end of the continuous polymerization reaction, in addition to obtaining the effect of increasing the molecular weight, the siloxane structure will undergo a condensation reaction with water during the wet coagulation process to form a network cross-linked structure, thereby improving the product Mooney viscosity and mechanical properties, and is beneficial to reducing rolling resistance.

[0035] As an optional embodiment, the molar ratio of the butadiene to the styrene is (1.5-4):1; and / or

[0036] The solvent comprises at least one of C5-C8 alkanes and C5-C8 cycloalkanes; and / or

[0037] The molar ratio of the structure regulator to the initiator is (2-8):1; and / or

[0038] The structure modifier comprises a polar Lewis base; and / or

[0039] The initiator comprises an organic lithium compound; and / or

[0040] The temperature of the copolymerization reaction is 70 to 140° C.; and / or the temperature of the modification reaction is 60 to 100° C.; and / or

[0041] The terminator comprises at least one of anhydrous ethanol, trimethylchlorosilane and fatty acid; and / or

[0042] The entire preparation process of the modified solution-polymerized styrene-butadiene rubber is a continuous preparation process.

[0043] The present application uses a capping monomer with a conjugated double bond to cap the intermediate polymer, and then performs modification and preparation. The resulting styrene-butadiene rubber chain end is a flexible structure with an active olefin double bond, which is easy to participate in the reaction during subsequent processing, thereby improving the performance of the product.

[0044] In a second aspect, the present application provides a terminal-modified solution-polymerized styrene-butadiene rubber, which is prepared by the preparation method of the terminal-modified solution-polymerized styrene-butadiene rubber described in the first aspect.

[0045] As an optional embodiment, the end-capped modified solution-polymerized styrene-butadiene rubber is a random high Mooney viscosity solution-polymerized styrene-butadiene rubber, whose base rubber Mooney viscosity (ML(1+4)120°C) is 100-180, the bound benzene content is 20-40%, the vinyl content is 30-70%, and the randomness is 100%.

[0046] As an optional embodiment, the number average molecular weight of the end-capped modified solution-polymerized styrene-butadiene rubber is 300,000 to 1,000,000 g / mol.

[0047] As an optional embodiment, the end-capped modified solution-polymerized styrene-butadiene rubber has terminal double bonds, that is, the end-capped modified solution-polymerized styrene-butadiene rubber has reactive active chains that can continue to participate in reactions in subsequent processing.

[0048] The above technical solution provided by this application has the following advantages compared with the existing technology:

[0049] (1) According to the preparation method of the present application, the polymer is end-capped by using an end-capping monomer with a conjugated double bond, thereby improving the problem that the molecular entanglement phenomenon of the high styrene structure and high Mooney viscosity continuous line product is more obvious due to the large molecular weight, and due to the difference in monomer reactivity ratio, the active chain ends of the molecules are mostly styrene units with large steric hindrance, which are not easy to participate in the reaction during the processing, resulting in poor filler dispersion;

[0050] (2) According to the preparation method of the present application, by using a capping monomer having a conjugated double bond to cap the polymer, the obtained solution-polymerized styrene-butadiene rubber has an active chain with a terminal double bond, thereby achieving the purpose of stabilizing the polymer molecular structure, meeting the applicability of the production equipment, and effectively improving the processing performance of the high-quality product;

[0051] (3) According to the preparation method of the present application, by performing end-capping treatment on the polymer, the solution-polymerized styrene-butadiene rubber product prepared has smooth edges compared to the unend-capped product, and will not crack at the edges to form "burrs";

[0052] (4) The present application adopts a continuous polymerization process to prepare solution-polymerized styrene-butadiene rubber, and the prepared product has stable, uniform, high-purity and extremely low gel content. In addition, the continuous polymerization production process has high production efficiency and low cost, and is suitable for the mass production of solution-polymerized styrene-butadiene rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0054] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0055] FIG1 is a flow chart of a method provided in an embodiment of the present application;

[0056] FIG2 is a nuclear magnetic resonance spectrum of the modified solution-polymerized styrene-butadiene rubber provided in Example 3 of the present application. DETAILED DESCRIPTION

[0057] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0058] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods. In addition, unless otherwise specified, the butadiene used in the present invention is 1,3-butadiene.

[0059] SSBR molecular weight is directly proportional to its Mooney viscosity and mechanical properties. This means that as the polymer molecular weight increases, the Mooney viscosity increases, and mechanical properties improve. However, this increase in Mooney viscosity is often accompanied by a decrease in processing performance. Therefore, the inventors aimed to improve the processing difficulties of linear, high-Mooney-viscosity products by adding end-capping monomers. The method adopts an organic lithium initiator and a Lewis base as a structure regulator in an inert gas protection environment, and uses C5-C8 alkanes or C5-C8 cycloalkanes, or a mixture of C5-C8 alkanes and C5-C8 cycloalkanes as a solvent. After completing the above polymerization steps, a small amount of end-capping monomers with conjugated double bonds are added again to end-cap the polymerization product, and then a modification reaction is carried out. A multi-arm modifier such as silicon halide, tin halide, siloxane, etc. is used as a modifier to synthesize a random high-styrene high-Mooney viscosity solution-polymerized styrene-butadiene rubber under specific process conditions. After the reaction is completed, the random high-Mooney viscosity solution-polymerized styrene-butadiene rubber is obtained through coagulation and drying. The base rubber has a Mooney viscosity (ML(1+4)120°C) of 100-180, a bound benzene content of 20-40%, a vinyl content of 30-70%, and a randomness of 100%. The raw materials of this modifier are easily available, cheap, easily soluble in solvents, and easy to remove; it can improve the disadvantages of linear products that are difficult to transport and process, forming a new process for the synthesis of solution-polymerized styrene-butadiene rubber, and relying on this process to form a technical platform that is widely used in the modification of various products to improve product performance.

[0060] As shown in FIG1 , the present application provides a method for preparing end-capped modified solution-polymerized styrene-butadiene rubber, the method comprising:

[0061] S1. In a multi-reactor continuous reaction process, styrene and butadiene are mixed in a solvent, and then mixed with a structure modifier and an initiator to allow the styrene and butadiene to undergo continuous copolymerization to obtain an intermediate polymer;

[0062] In some embodiments, the molar ratio of the butadiene to the styrene is (1.5-4):1 (eg, 2:1, 2.5:1, 3:1, or 3.5:1).

[0063] In some embodiments, the solvent includes at least one of C5-C8 alkanes and C5-C8 cycloalkanes. Specifically, the solvent can be selected from cyclohexane, hexane, cyclopentane, pentane, heptane, raffinate oil and benzene, and one or more of them can be selected and used as needed.

[0064] In some embodiments, the initiator comprises an organolithium compound; specifically, the initiator can be selected from organolithium compounds such as n-butyllithium, sec-butyllithium, amyllithium, ethyllithium, propyllithium, and isopropyllithium, with n-butyllithium or sec-butyllithium being preferred. The addition amount can be appropriately determined based on the existing solution butadiene styrene polymerization process conditions and the microstructural requirements of the synthesized product.

[0065] In some embodiments, the structure modifier includes a polar Lewis base. Specifically, the polar Lewis base can be a strong polar Lewis base or a weak polar Lewis base. The strong polar Lewis base can be selected from hexamethylphosphoramide (HMPA), diethylene glycol dimethyl ether (2G), triethylene glycol dimethyl ether (1G), dimethoxyethane (DME), 2,2-bis(2-tetrahydrofuryl)propane (DTHFP), ethyl tetrahydrofurfuryl ether (ETE), etc.; the weak polar Lewis base can be selected from tetrahydrofuran (THF), p-dioxane (DOX), diethyl ether, triethylamine (Et3N), sodium dodecylbenzenesulfonate, etc., and one, two, or more thereof can be selected and used in combination according to the requirements of polymer synthesis. The molar ratio of the structure modifier to the initiator is (2-8):1 (e.g., 3:1, 4:1, 5:1, 6:1, or 7:1).

[0066] In some embodiments, the temperature of the copolymerization reaction is 70-140°C; since the copolymerization of butadiene and styrene to prepare solution butadiene styrene rubber is an exothermic reaction, the temperature of the reaction system increases as the copolymerization reaction continues. About half an hour after the start of the copolymerization reaction, depending on the reaction conditions, the temperature of the reaction system can reach 70-140°C (for example, 75°C, 80°C, 90°C, 100°C, 110°C, 120°C or 130°C), preferably 80-100°C (for example, 85°C, 90°C or 95°C).

[0067] It should be noted that the present application does not impose any particular restrictions on the order in which the components are added prior to the copolymerization reaction; the order can be reasonably determined based on the order of addition in conventional solution-polymerized styrene-butadiene rubber preparation processes. Typically, the hydrocarbon solvent, butadiene, styrene, and structure modifier (i.e., the raw materials other than the organolithium initiator) are first uniformly mixed. The system is then heated to the initiation temperature of the organolithium initiator, and finally, the organolithium initiator is added to initiate the copolymerization reaction of styrene and butadiene. The continuous addition of the various materials is then maintained to achieve continuous production.

[0068] S2. The intermediate polymer and the end-capping monomer are mixed to perform an end-capping reaction to obtain an end-capped polymer; the end-capping monomer having a conjugated double bond;

[0069] In some embodiments, the end-capping monomer includes, but is not limited to, a conjugated olefin compound. Furthermore, the conjugated olefin compound may be butadiene, pentadiene, or isoprene, one or two of which may be selected and used as needed. Furthermore, the end-capping monomer is added in an amount of 0.5% to 5% (e.g., 1%, 2%, 3%, 4%, or 4.5%) based on the total weight of the styrene and butadiene.

[0070] S3. Mixing the end-capped polymer and a modifier to perform a modification reaction to obtain a modified polymer; wherein the modifier includes a multi-arm modifier having at least two arm structures.

[0071] In some embodiments, the multi-arm modifier includes a two-arm modifier and a three-arm modifier. Furthermore, the two-arm modifier includes a halide containing a two-arm structure; the three-arm modifier includes a siloxane containing a three-arm structure, wherein the siloxane group includes at least one of an amino group, a methoxy group, a carboxyl group, a thiol group, and a hydroxyl group. Furthermore, the halide containing a two-arm structure includes diphenyldichlorosilane.

[0072] In some embodiments, the multi-arm modifier includes a siloxane having a multi-arm structure. The siloxane group includes at least one of an amino group, a methoxy group, a carboxyl group, a sulfhydryl group, and a hydroxyl group. Further, the siloxane includes at least one of 3-chloropropyltrimethoxysilane, 3-chloropropyldimethoxymethylsilane, and N-[3-(triethoxysilyl)propyl]-4,5-dihydroimidazole.

[0073] In some embodiments, the molar ratio of the modifier to the initiator is (1.5-70):100 (e.g., 2:100, 5:100, 10:100, 20:100, 30:100, 40:100, 50:100, or 60:100). Furthermore, when a three-arm or less structure modifier is used, the molar ratio of the modifier to the total amount of the initiator is approximately (15-70):100 (e.g., 20:100, 30:100, 40:100, 50:100, or 60:100). One of these modifiers can be used alone or in combination, depending on the needs.

[0074] In some embodiments, the temperature of the modification reaction is 60-100°C (for example, 65°C, 70°C, 75°C, 80°C, 90°C or 95°C). As the polymerization reaction continues during the transportation process, the amount of monomer in the system gradually decreases, the heat released by the system decreases, and the temperature of the polymerization kettle gradually decreases. When the modification step is carried out, the temperature of the reactor is generally 60-100°C, preferably 70-90°C (for example, 72°C, 75°C, 80°C, 85°C or 88°C).

[0075] S4. The modified polymer and the terminator are mixed to obtain a capped modified solution styrene-butadiene rubber;

[0076] In some embodiments, the terminator can be selected from a group consisting of fatty acids, anhydrous ethanol, trimethylsilyl chloride, and other terminating agents, with one selected as needed. The terminator is added after the total reaction time of the copolymerization and modification reaction reaches 2 to 6 hours (e.g., 3 hours, 4 hours, 5 hours, or 5.5 hours).

[0077] In some embodiments, the terminator is selected from fatty acids.

[0078] In the present invention, fatty acid is used as a terminator. Since fatty acid contains carboxyl group, it reacts with active chain to generate aliphatic hydrocarbon (i.e. saturated hydrocarbon with 20 to 50 carbon atoms), which can be mixed in the glue to act as a small molecule to lubricate and will not affect product quality and subsequent production.

[0079] In some embodiments, the entire preparation process of the modified solution-polymerized styrene-butadiene rubber is a continuous preparation process. Specifically, in the present invention, the reaction vessel of the continuous process includes a first polymerization kettle, a second polymerization kettle, a third polymerization kettle, a fourth polymerization kettle, and a fifth polymerization kettle. The step of adding the hydrocarbon solvent, styrene, and butadiene into the reaction vessel and stirring and mixing them specifically includes: adding the hydrocarbon solvent, the styrene, and the butadiene into the first polymerization kettle and stirring and mixing them; the step of adding the structure regulator and the organic lithium into the reaction vessel and making the styrene and the butadiene copolymerize in the hydrocarbon solvent specifically includes: adding the structure regulator and the organic lithium into the first polymerization kettle and making the styrene and the butadiene copolymerize in the hydrocarbon solvent for a first time; The first product is transported to the second polymerization vessel, and the first product is subjected to a second-stage copolymerization reaction in the second polymerization vessel to obtain a second product; the second product is transported to the third polymerization vessel, and the second product is subjected to a third-stage copolymerization reaction in the third polymerization vessel to obtain a third product; the third product is transported to the fourth polymerization vessel, and the third product is subjected to a fourth-stage copolymerization reaction in the fourth polymerization vessel to obtain a fourth product; the fourth product is transported to the fifth polymerization vessel, and the modifier is added thereto, and the fourth product is subjected to a fifth-stage copolymerization reaction in the fifth polymerization vessel. Prior to the step of adding the hydrocarbon solvent, styrene, and butadiene into the reaction vessel and stirring and mixing, the preparation method further comprises: introducing an inert gas into the reaction vessel. The first reaction kettle temperature is 70-140°C (for example, 75°C, 80°C, 90°C, 100°C, 110°C, 120°C or 130°C), and the modification process reactor temperature range is: 60-100°C (for example, 65°C, 70°C, 75°C, 80°C, 90°C or 95°C), preferably 70-90°C (for example, 72°C, 75°C, 80°C, 85°C or 88°C).

[0080] It should be noted that under multi-reactor continuous polymerization conditions, the conversion rate and microstructure of the solution-polymerized styrene-butadiene rubber product can be controlled by controlling the temperature of the first reactor and the ratio of the structure regulator. The polymerization reaction is considered complete after adding the end-capping monomer after 2 to 4 hours of reaction, followed by an additional hour of reaction, followed by the addition of the modifier and an additional hour of reaction. The amount of modified segments in the product can be adjusted by adjusting the amount of modifier added to obtain products with different mechanical properties, and the processing properties of the product can be improved by adding additional end-capping monomer.

[0081] In some embodiments, the method further comprises: drying the modified solution-polymerized styrene-butadiene rubber, specifically comprising: transferring the modified solution-polymerized styrene-butadiene rubber into a vacuum drying oven and drying it at a temperature of 60° C. to 70° C. for 12 to 13 hours.

[0082] The method is simple, has a fast polymerization rate, can realize industrial continuous and stable production, and the product has excellent mechanical properties and balanced wear resistance, rolling resistance and anti-skid performance.

[0083] Based on a general inventive concept, the present application also provides an end-capped modified solution-polymerized styrene-butadiene rubber, which is prepared by the preparation method of the end-capped modified solution-polymerized styrene-butadiene rubber provided above.

[0084] The modified solution-polymerized styrene-butadiene rubber has excellent processing performance, and the sample is smooth and has no burrs.

[0085] The end-capped modified solution-polymerized styrene-butadiene rubber is prepared based on the above method. The specific steps of the method can be referred to the above embodiment. Since the modified solution-polymerized styrene-butadiene rubber adopts part or all of the technical solutions of the above embodiment, it at least has all the beneficial effects brought about by the technical solutions of the above embodiment, which will not be repeated here.

[0086] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or according to the conditions recommended by the manufacturer.

[0087] Example 1

[0088] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 4 kg / h of styrene, 6 kg / h of butadiene, and 66 kg / h of cyclopentane into a first reactor under continuous polymerization system conditions; using ETE as a structural regulator; the molar ratio of the ETE feed amount to the initiator n-butyl lithium being 3.5:1; the polymerization time of the first reactor being 60 minutes, the reaction temperature being 75°C; the reaction mixture entering a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 80%; the reaction mixture entering a third reactor for reaction for 1 hour when the conversion rate reaches 90%; the reaction mixture entering a fourth reactor after the addition of an end-capping monomer, the end-capping monomer being butadiene, the feed amount being 0.3 kg; the reaction mixture reaching 100% after the reaction for 1 hour; the addition of a modifier, 3-chloropropyldimethoxymethylsilane, into a fifth reactor; the molar ratio of the 3-chloropropyldimethoxymethylsilane to the total amount of the initiator n-butyl lithium being 2.5:100; the reaction temperature of the fifth reactor being 68°C; and finally, terminating the reaction with fatty acid at the outlet of the fifth reactor. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 316,000 g / mol.

[0089] Example 2

[0090] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 3 kg / h of styrene, 7 kg / h of butadiene, and 66 kg / h of cyclopentane into a first reactor under continuous polymerization system conditions; using ETE as a structural regulator; the molar ratio of the ETE feed amount to the initiator n-butyl lithium being 5:1; polymerizing for 60 minutes at a reaction temperature of 84°C; entering a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 83%; entering a third reactor for reaction for 1 hour when the conversion rate reaches 97%; adding an end-capping monomer into a fourth reactor; the end-capping monomer being butadiene in an amount of 0.5 kg; and the conversion rate reaching 100% after reaction for 1 hour; adding a modifier 3-chloropropyltrimethoxysilane into a fifth reactor; the reaction temperature of the fifth reactor being 77°C; and the molar ratio of the total amount of 3-chloropropyltrimethoxysilane to the initiator n-butyl lithium being 3.5:100; and finally terminating with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 489,000 g / mol.

[0091] Example 3

[0092] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 3 kg / h of styrene, 7 kg / h of butadiene, and 66 kg / h of cyclopentane into a first reactor under continuous polymerization system conditions; using 2G as a structural regulator; the molar ratio of the 2G feed amount to the initiator n-butyl lithium being 6:1; polymerizing for 60 minutes at a reaction temperature of 90°C; entering a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 85%; entering a third reactor for reaction for 1 hour when the conversion rate reaches 94%; adding an end-capping monomer into a fourth reactor; the end-capping monomer being butadiene in an amount of 0.4 kg; and the conversion rate reaching 100% after reaction for 1 hour; adding a modifier 3-chloropropyltrimethoxysilane into a fifth reactor; the reaction temperature of the fifth reactor being 83°C; and the molar ratio of the total amount of 3-chloropropyltrimethoxysilane to the initiator n-butyl lithium being 15:100; and finally terminating with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 770,000 g / mol.

[0093] Example 4

[0094] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 2.5 kg / h of styrene, 7.5 kg / h of butadiene, and 66 kg / h of cyclopentane into a first reactor under continuous polymerization system conditions; using 2G as a structural regulator; the molar ratio of the 2G feed amount to the initiator n-butyl lithium being 7:1; polymerizing for 60 minutes at a reaction temperature of 70°C; entering a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 90%; entering a third reactor for reaction for 1 hour when the conversion rate reaches 95%; adding an end-capping monomer into a fourth reactor; the end-capping monomer being butadiene in an amount of 0.2 kg; and reacting for 1 hour to achieve a conversion rate of 100%; adding a modifier 3-chloropropyldimethoxymethylsilane into a fifth reactor; the reaction temperature of the fifth reactor being 74°C; and the molar ratio of the total amount of 3-chloropropyldimethoxymethylsilane to the initiator n-butyl lithium being 30:100; and finally terminating with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 930,000 g / mol.

[0095] Example 5

[0096] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises the following steps: under continuous polymerization system conditions, continuously feeding a first reactor with 2.5 kg / h of styrene, 7.5 kg / h of butadiene, and 66 kg / h of cyclopentane; using DTHFP as a structural regulator; the molar ratio of the DTHFP feed amount to the initiator n-butyl lithium being 3:1; the polymerization time of the first reactor being 60 minutes, the reaction temperature being 88°C, and the conversion rate reaching 85%; then feeding the first reactor to a second reactor for reaction for 1 hour; and then feeding the first reactor to a third reactor for reaction for 1 hour when the conversion rate reaches 89%; then feeding the first reactor to a fourth reactor for reaction; the end-capping monomer being 0.1 kg of butadiene; and the conversion rate reaching 100% after reaction for 1 hour; then feeding the first reactor to a fifth reactor; the reaction temperature of the fifth reactor being 80°C, and the molar ratio of the total amount of 3-chloropropyltrimethoxysilane to the initiator n-butyl lithium being 12:100; and finally terminating the reaction with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 443,000 g / mol.

[0097] Example 6

[0098] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 4 kg / h of styrene, 6 kg / h of butadiene, and 66 kg / h of cyclopentane to a first reactor under continuous polymerization system conditions; using DTHFP as a structure regulator; the molar ratio of DTHFP feed to initiator n-butyl lithium is 3:1; the first reactor polymerization time is 60 minutes, the reaction temperature is 85°C, the conversion rate reaches 84%, the reactor is fed into a second reactor for reaction for 1 hour, and the conversion rate reaches 87%, the reactor is fed into a third reactor for reaction. After 1 hour, the conversion rate reached 94%. The end-capping monomer, 0.1 kg of butadiene, was added to the fourth reactor. After 1 hour of reaction, the conversion rate reached 100%. The modifier, N-[3-(triethoxysilyl)propyl]-4,5-dihydroimidazole, was added and the reaction was continued to the fifth reactor. The reaction temperature in the fifth reactor was 76°C, and the molar ratio of N-[3-(triethoxysilyl)propyl]-4,5-dihydroimidazole to the initiator, n-butyl lithium, was 20:100. The reaction was terminated with a fatty acid. The resulting product was dried in a vacuum oven at 60°C for 12 hours to obtain an end-capped, modified solution-polymerized styrene-butadiene rubber with a number-average molecular weight of 650,000 g / mol.

[0099] Example 7

[0100] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises the following steps: under continuous polymerization system conditions, continuously feeding a first reactor with 4 kg / h of styrene, 6 kg / h of butadiene, and 66 kg / h of cyclopentane; using 1G as a structural regulator; the molar ratio of the 1G feed to the initiator n-butyl lithium being 3.5:1; the polymerization time of the first reactor being 60 minutes, the reaction temperature being 85°C, the reaction mixture being fed into a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 87%, the reaction mixture being fed into a third reactor for reaction for 1 hour when the conversion rate reaches 90%, the reaction mixture being fed into a fourth reactor for reaction when the conversion rate reaches 97%, the end-capping monomer being butadiene in an amount of 0.2 kg, and the reaction mixture being fed into a fifth reactor when the reaction temperature is 72°C, and the total molar ratio of diphenyldichlorosilane to the initiator n-butyl lithium being 18:100; and finally, the rubber is terminated with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 420,000 g / mol.

[0101] Example 8

[0102] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: continuously feeding 2.5 kg / h of styrene, 7.5 kg / h of butadiene, and 66 kg / h of cyclopentane into a first reactor under continuous polymerization system conditions; using ETE as a structural regulator; the molar ratio of the ETE feed amount to the initiator n-butyl lithium being 6:1; polymerizing for 60 minutes at a reaction temperature of 90°C; entering a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 88%; entering a third reactor for reaction for 1 hour when the conversion rate reaches 98%; adding an end-capping monomer, which is 0.3 kg of butadiene, into a fourth reactor; and reacting for 1 hour to achieve a conversion rate of 100%; adding a modifier, diphenyldichlorosilane, into a fifth reactor; the reaction temperature of the fifth reactor being 81°C; and the total molar ratio of diphenyldichlorosilane to the initiator n-butyl lithium being 45:100; and finally terminating with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber with a number average molecular weight of 810,000 g / mol.

[0103] Example 9

[0104] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises the following steps: under continuous polymerization system conditions, continuously feeding a first reactor with 3 kg / h of styrene, 7 kg / h of butadiene, and 66 kg / h of cyclopentane; using 2G as a structural regulator; the molar ratio of the 2G feed to the initiator n-butyl lithium being 6.5:1; the polymerization time of the first reactor being 60 minutes, the reaction temperature being 100°C, the reaction mixture being fed into a second polymerization reactor for reaction for 1 hour when the conversion rate reaches 87%, the reaction mixture being fed into a third reactor for reaction for 1 hour when the conversion rate reaches 90%, the reaction mixture being fed into a fourth reactor for reaction when the conversion rate reaches 97%, the end-capping monomer being butadiene in an amount of 0.4 kg, the reaction mixture being fed into a fifth reactor when the reaction temperature is 91°C, the reaction mixture being fed into a fifth reactor when the reaction temperature is 91°C, the molar ratio of the total amount of diphenyldichlorosilane to the initiator n-butyl lithium being 70:100, and finally being terminated with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 710,000 g / mol.

[0105] Example 10

[0106] A method for preparing end-capped modified solution-polymerized styrene-butadiene rubber comprises: under continuous polymerization system conditions, continuously feeding a first reactor with 4 kg / h of styrene, 6 kg / h of butadiene, and 66 kg / h of cyclopentane; using ETE as a structural regulator; the molar ratio of the ETE feed amount to the initiator n-butyl lithium being 4:1; the polymerization time of the first reactor being 60 minutes, the reaction temperature being 80°C, and the conversion rate reaching 85%; then entering a second polymerization reactor for reaction for 1 hour; and when the conversion rate reaches 90%, entering a third reactor for reaction for 1 hour; and when the conversion rate reaches 95%, adding an end-capping monomer; and then entering a fourth reactor; the end-capping monomer being butadiene, the feeding amount being 0.5 kg; and the conversion rate reaching 100% after reaction for 1 hour; and adding a modifier 3-chloropropyltrimethoxysilane; and then entering a fifth reactor; the reaction temperature of the fifth reactor being 74°C, and the molar ratio of the total amount of 3-chloropropyltrimethoxysilane to the initiator n-butyl lithium being 70:100; and finally terminating with fatty acid. The obtained product was dried in a vacuum drying oven at 60° C. for 12 h to obtain an end-capped modified solution-polymerized styrene-butadiene rubber having a number average molecular weight of 380,000 g / mol.

[0107] Comparative Example 1

[0108] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 1. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 303,000 g / mol.

[0109] Comparative Example 2

[0110] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 2. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 476,000 g / mol.

[0111] Comparative Example 3

[0112] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 3. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 624,000 g / mol.

[0113] Comparative Example 4

[0114] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 4. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 726,000 g / mol.

[0115] Comparative Example 5

[0116] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 5. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 428,000 g / mol.

[0117] Comparative Example 6

[0118] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 6. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 414,000 g / mol.

[0119] Comparative Example 7

[0120] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 7. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 348,000 g / mol.

[0121] Comparative Example 8

[0122] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 8. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 564,000 g / mol.

[0123] Comparative Example 9

[0124] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 9. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 586,000 g / mol.

[0125] Comparative Example 10

[0126] Except that no modifier was added, the rest of the contents of this comparative example were the same as those of Example 10. The number average molecular weight of the obtained end-capped modified solution-polymerized styrene-butadiene rubber was 316,000 g / mol.

[0127] Comparative Example 11

[0128] This comparative example is the same as Example 1 except that no end-capping monomer is added and the reaction temperature of the first polymerization kettle is 70° C. and the reaction temperature of the fifth polymerization kettle is 65° C. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 313,000 g / mol.

[0129] Comparative Example 12

[0130] This comparative example is the same as Example 2 except that no end-capping monomer is added and the reaction temperature of the first polymerization kettle is 80° C. and the reaction temperature of the fifth polymerization kettle is 72° C. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 484,000 g / mol.

[0131] Comparative Example 13

[0132] Except that no end-capping monomer was added, the rest of the contents of this comparative example were the same as those of Example 3. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber was 761,000 g / mol.

[0133] Comparative Example 14

[0134] Except for not adding the end-capping monomer, the other contents of this comparative example are the same as those of Example 4. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 918,000 g / mol.

[0135] Comparative Example 15

[0136] This comparative example is the same as Example 5 except that no end-capping monomer is added and the reaction temperature of the first polymerization kettle is 90° C. and the reaction temperature of the fifth polymerization kettle is 85° C. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 439,000 g / mol.

[0137] Comparative Example 16

[0138] Except for not adding the end-capping monomer, the rest of the contents of this comparative example are the same as those of Example 6. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 637,000 g / mol.

[0139] Comparative Example 17

[0140] Except that no end-capping monomer was added, the rest of the contents of this comparative example were the same as those of Example 7. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber was 412,000 g / mol.

[0141] Comparative Example 18

[0142] Except for not adding the end-capping monomer, the rest of the contents of this comparative example are the same as those of Example 8. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 797,000 g / mol.

[0143] Comparative Example 19

[0144] Except for not adding the end-capping monomer, the rest of the contents of this comparative example are the same as those of Example 9. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber is 697,000 g / mol.

[0145] Comparative Example 20

[0146] Except that no end-capping monomer was added, the rest of the contents of this comparative example were the same as those of Example 10. The number average molecular weight of the obtained solution-polymerized styrene-butadiene rubber was 373,000 g / mol.

[0147] Comparative Example 21

[0148] This comparative example provides a method for preparing solution-polymerized styrene-butadiene rubber, which differs from Example 1 in that the amount of end-capping agent used is different. Specifically, the method comprises the following steps:

[0149] Under the conditions of a continuous polymerization system, the first reactor is continuously fed with 4 kg / h of styrene, 6 kg / h of butadiene, and 66 kg / h of cyclopentane. ETE is used as a structure regulator, and the molar ratio of ETE feed to initiator n-butyl lithium is 3.5:1. The polymerization time of the first reactor is 60 minutes, the reaction temperature is 70°C, and the conversion rate reaches 80%. The reactor enters the second polymerization reactor for reaction for 1 hour. The conversion rate reaches 90%, and the reactor enters the third reactor for reaction for 1 hour. The conversion rate reaches 95%. After the end-capping monomer is added, the reactor enters the fourth reactor. The end-capping monomer is butadiene, and the feed amount is 0.7 kg. After the reaction for 1 hour, the conversion rate reaches 100%. The modifier 3-chloropropyldimethoxymethylsilane is added to the fifth reactor. The molar ratio of 3-chloropropyldimethoxymethylsilane to the total amount of initiator n-butyl lithium is 2.5:100. The reaction temperature of the fifth reactor is 65°C, and the reactor is terminated with fatty acid at the outlet of the fifth reactor. The resulting product was dried in a vacuum drying oven at 60°C for 12 hours to obtain an end-capped modified solution-polymerized styrene-butadiene rubber. The end-capped modified solution-polymerized styrene-butadiene rubber contained a small amount of block polybutadiene, reducing randomness. The number average molecular weight of the resulting end-capped modified solution-polymerized styrene-butadiene rubber was 318,000 g / mol.

[0150] The solution-polymerized styrene-butadiene rubbers provided in Examples 1-10 and Comparative Examples 1-21 were characterized, and the results are shown in Table 1 below.

[0151] Table 1

[0152] * 1 :The values ​​in brackets in the microstructure are rounded to two decimal places;* 2 : 1,2-,% represents the content of 1,2-olefin in solution polystyrene butadiene rubber, that is, the vinyl content.

[0153] As can be seen from the table above, the solution-polymerized styrene-butadiene rubber produced using the methods provided in the examples of the present application has a higher Mooney viscosity. Comparison of the various examples shows that the present invention, depending on the type of modifier, can alter the polymer molecular structure, thereby affecting the product's Mooney viscosity and mechanical properties. After polymerization, high-Mooney viscosity solution-polymerized styrene-butadiene rubber is obtained through coagulation and drying, with the sample exhibiting a random distribution. This demonstrates that the present invention can produce random high-Mooney viscosity solution-polymerized styrene-butadiene rubber.

[0154] As can be seen from the above table, the solution-polymerized styrene-butadiene rubber prepared by the method provided in the examples of the present application has better physical and mechanical properties.

[0155] Detailed description of Figure 2:

[0156] FIG2 is a nuclear magnetic spectrum of the modified solution-polymerized styrene-butadiene rubber provided in Example 3. It can be seen from the figure that the polymerization product has a chromatographic distribution of 6 to 6.5 cm -1 There is no obvious chemical shift between the two groups, so there is no blocked styrene chain segment and the randomness is 100%. According to the peak area calculation, the styrene content of the polymerization product is 28.5% and the vinyl content is 53.2%.

[0157] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0158] In this application, unless otherwise specified, the directional words used, such as "upper" and "lower", refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0159] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A preparation method of a capped and modified solution polymerized styrene-butadiene rubber, characterized in that, The method includes: In a multi-kettle continuous reaction process, styrene and butadiene are mixed in a solvent, and then mixed with a structure regulator and an initiator to cause the styrene and butadiene to carry out a continuous copolymerization reaction to obtain an intermediate polymer; Multiple injection points and a tubular reactor are added to the continuous polymerization reaction path, and the intermediate polymer and a capping monomer are mixed to carry out a capping reaction to obtain a capped polymer; The capped polymer is mixed with a modifier to carry out a modification reaction to obtain a modified polymer; The modified polymer is mixed with a terminator to obtain a capped modified solution-polymerized styrene-butadiene rubber; Wherein, the structure regulator includes a polar Lewis base; the initiator includes an organolithium compound; the capping monomer is at least one of butadiene, pentadiene and isoprene; the modifier is at least one of a halide containing a two-arm structure and a siloxane containing a multi-arm structure; the halide containing a two-arm structure is diphenyldichlorosilane, and the siloxane containing a multi-arm structure is at least one of 3-chloropropyltrimethoxysilane, 3-chloropropyldimethoxymethylsilane and N-[3-(triethoxysilyl)propyl]-4,5-dihydroimidazole; The added weight of the capping monomer is 0.5% to 5% of the total weight of the styrene and butadiene; the molar ratio of the dosage of the modifier to the initiator is (1.5 to 70):100; the temperature of the copolymerization reaction is 70 to 140 °C; the temperature of the modification reaction is 60 to 100 °C; When the number of arm structures of the multi-arm modifier does not exceed 3, the molar ratio of the dosage of the modifier to the initiator is (15 to 70):

100.

2. The preparation method of the capped modified solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that, The added weight of the capping monomer is 2% to 3% of the total weight of the styrene and butadiene.

3. The preparation method of the capped modified solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that, The solvent includes at least one of C5-C8 alkanes and C5-C8 cycloalkanes; and / or The molar ratio of the structure regulator to the initiator is (2 to 8):1; and / or The terminator includes at least one of absolute ethanol, trimethylchlorosilane and fatty acid; and / or The entire preparation process of the capped modified solution-polymerized styrene-butadiene rubber is a continuous preparation method.

4. A capped and modified solution-polymerized styrene-butadiene rubber, characterized in that, The capped modified solution-polymerized styrene-butadiene rubber is prepared by the preparation method of the capped modified solution-polymerized styrene-butadiene rubber according to any one of claims 1 to 3.

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