Double-end multifunctional solution polymerized styrene-butadiene rubber, composite material of double-end multifunctional solution polymerized styrene-butadiene rubber and white carbon black, and preparation method of composite material

Abstract

The invention discloses double-end multifunctional solution polymerized styrene-butadiene rubber, a composite material of the double-end multifunctional solution polymerized styrene-butadiene rubber and white carbon black and a preparation method of the double-end multifunctional solution polymerized styrene-butadiene rubber, the structure of the double-end multifunctional solution polymerized styrene-butadiene rubber is shown in the formula (1): # imgabs0 #, and z and m are the same or different and are independently selected from integers between 1 and 10; r6, R7 and R8 are the same or different and are independently selected from straight-chain alkyl with the carbon atom number of 1-10, cyclic alkyl, phenyl, reactive hydrogen or alkoxy; and R9 and R10 are the same or different and are independently selected from phenyl, reactive hydrogen, hydroxyl or alkoxy. Different polar functional groups are introduced to two ends of a main chain of the solution polymerized styrene-butadiene rubber to prepare the double-end multifunctional solution polymerized styrene-butadiene rubber, the interfacial compatibility of the SSBR and the white carbon black is increased due to the introduction of the groups, the dispersity of the solution polymerized styrene-butadiene rubber in filler is effectively improved, and the comprehensive mechanical property of the SSBR vulcanized rubber is improved.

Description

Technical Field

[0001] The invention belongs to the field of synthetic rubber and relates to a multifunctional solution-polymerized styrene-butadiene rubber, in particular to a double-end multifunctional solution-polymerized styrene-butadiene rubber, a composite material formed by the solution-polymerized styrene-butadiene rubber and white carbon black, and a preparation method thereof. Background Art

[0002] Solution-polymerized styrene butadiene rubber is a polymer obtained by anionic living polymerization of butadiene and styrene, which was developed in the 1980s. Compared with emulsion-polymerized styrene butadiene rubber (ESBR) prepared by free radicals, solution-polymerized styrene butadiene rubber (SSBR) has a narrower relative molecular weight distribution, a larger relative molecular weight and excellent molecular chain characteristics, so it has relatively low hysteresis loss, excellent wear resistance and groove crack resistance, wet road grip performance, heat resistance and good flexural resistance after long-term exposure to high temperature, etc., and has become a recognized important raw material for the development of green tires.

[0003] At present, the preparation technology of solution-polymerized styrene-butadiene rubber has developed to the fourth generation, and has gone through stages such as linear SSBR, carbon black system functionalized SSBR, integrated rubber and white carbon black system functionalized SSBR. At the end of the last century, the technology had developed to the fourth generation abroad and was successfully industrialized. At present, China has completed the industrial test of amine-functionalized SSBR, which is mainly aimed at the carbon black filling system. There are no industrial products under the higher performance and greener white carbon black system, and China is still in a blank stage.

[0004] Functionalized solution-polymerized styrene-butadiene rubber refers to the introduction of polar groups such as N, Si, O, Sn, and P on its polymer chain. The introduction of these groups realizes the transformation of molecular polarity from hydrophobic to hydrophilic, thereby increasing the interfacial compatibility between SSBR and polar filler silica, which is beneficial to the interaction with the filler, thereby promoting the dispersion of the filler in the rubber matrix; at the same time, due to the interaction between the end and the filler or the interaction itself, the degree of freedom of the chain link between the final cross-linking point and the chain end in the rubber network is reduced, so that it can effectively participate in the elastic recovery of the entire cross-linking network, thereby reducing the energy loss in periodic deformation, improving heat generation and rolling resistance, and improving the comprehensive performance of SSBR vulcanizate. In recent years, the modification research on SSBR has been relatively active, mainly including three methods or their combination forms of functionalization modification of molecular chain ends, grafting modification technology in molecular chains, and functionalized initiators to modify single-functionalized or multi-functionalized SSBR. Currently, the number of literature and patents reporting on the grafting modification of SSBR chains is far less than that of chain end modification, and the content is not exhaustive. The polar groups are expensive and difficult to prepare, and they are even rarer in China.

[0005] There are two main methods for preparing end-functionalized polymers by living anionic polymerization. One is to use a functionalized initiator that can initiate the polymerization of specific monomers. After the polymerization is completed, the functionalized group can be treated or retained. The advantage is that double-end multifunctionalized SSBR can be further prepared, and the synthesis process is simple and efficient. The disadvantage is that the preparation of functionalized initiators is difficult and has poor solubility in non-polar solvents such as alkanes. The second is to use functionalized electrophilic reagents to cap the active polymers and introduce a series of functionalized groups at the end of the polymer chain. Monofunctionalized or multifunctionalized SSBR can be prepared. The process is simple and easy, and the cost is low. It is the preferred solution for preparing multifunctionalized SSBR. The disadvantage is that the upper limit of the number of functional groups is low, and the functionalized capping reagents need to be screened in the early stage.

[0006] [Kenichi Uesaka, Tetsuya Kunisawa. Rubber composition for tire and pneumatic tire [P]. China: CN102212218, 2011-10-12], Sumitomo Corporation added n-butyl lithium hexane solution dropwise to a hexane solution of 1,3-divinylbenzene to obtain a multifunctional polymerization initiator, used this initiator solution to copolymerize butadiene and styrene, and then added a modifier tetraglycidyl-1,3-diaminomethylcyclohexane for modification. The resulting polymer was combined with white carbon black and had excellent low heat generation performance, wet grip performance and wear resistance.

[0007] [Marechal Jean-Marc. Novel Initiation System for the AnionicPolymerization of Conjugated Dienes and Method for Preparing Diene Elastomers [P]. USA: USP0251354A1, 2011-10-13], Michelin uses organic lithium compounds and tetravalent tin amine compounds as the initiation system to synthesize amine-functionalized SSBR, and then uses a tin halide coupling agent for modification. The synthesized SSBR has low hysteresis loss and good dynamic and physical properties.

[0008] [Yoon Du Weon, Lee Tae Chul. Bifunctional Organic Lithium Initiator and Conjugate Diene System Copolymer Produced Using Same [P]. EP 2336137A2, 2011-06-22.] LG Chemical uses a new bifunctionalized lithium amine initiator and alkoxysilane modifier to synthesize SSBR. The prepared product has high compatibility with inorganic reinforcing materials and has good anti-skid performance, rolling resistance and wear resistance.

[0009] [Hidetoshi Suzuki, Yoichi Ozawa. Modified conjugated diene polymers, polymerization initiators, preparation methods thereof and rubber compositions [P]. China: CN 1961011A, 2007-05-09.] Bridgestone Corporation reacts a diamine compound with a silyl compound to generate a silylated diamine compound, and then adds an organic alkali metal compound or an organic alkaline earth metal compound to the compound to generate an amine initiator. The styrene-butadiene copolymer rubber prepared by initiating the polymerization of styrene and butadiene with the initiator has good interaction with the inorganic filler and low heat generation.

[0010] [Liu Xiao, Zhao Suhe, Zhang Xingying, et al. Preparation, structure and properties of terminal functionalized solution polymerized styrene butadiene rubber and its composites [J]. Rubber Industry, 2009, 56 (6): 325-332] and [Tong Yuanyuan, Xu Limin, Bai Yu, et al. Star-shaped solution polymerized styrene butadiene rubber modified with γ-chloropropyltrimethoxysilane end groups [J]. Synthetic Rubber Industry, 2011, 34 (2): 111-116]. Solution polymerized styrene butadiene rubber with alkoxysilane functionalization at the end with a capping rate of 71%-76% was prepared using dilithium initiator, and the structure and properties of the rubber and silica composites were studied. The results show that under the condition of the same amount of silica, the composite has better filler dispersion, mechanical properties, anti-skid performance and low rolling resistance.

[0011] CN 110387071 A discloses a branched functionalized solution-polymerized styrene-butadiene rubber / white carbon black composite material. The composite material contains 50-83 parts of solution-polymerized styrene-butadiene rubber, 17-50 parts of white carbon black, and 0-5 parts of auxiliary agents based on 100 parts of the composite material. The chain of the solution-polymerized styrene-butadiene rubber contains α-branched modified siloxane, and the auxiliary agent is selected from antioxidants, etc. However, the technology uses the side chain (i.e., 1,2 structure) of butadiene in the styrene-butadiene polymer for functionalization, which belongs to chain functionalization. Moreover, the functionalizing agent is connected to the unsaturated double bond in the chain through a certain reaction, and the functional group is single.

[0012] CN 108997531 A discloses a multifunctional solution-polymerized styrene-butadiene rubber containing siloxy groups / amino groups at the chain end and in the chain. The multifunctional solution-polymerized styrene-butadiene rubber containing siloxy groups / amino groups at the chain end and in the chain is a terpolymer of butadiene, styrene and a 1,1-diphenylethylene derivative monomer containing siloxy groups / amino groups. The copolymer contains no less than two 1,1-diphenylethylene derivative units containing siloxy groups / amino groups, which can be at the chain end or in the chain. The proportion of each component in the multifunctional solution-polymerized styrene-butadiene rubber containing siloxy groups / amino groups at the chain end and in the chain is based on 100% of the total amount of the terpolymer, wherein the mass percentage of the combined 1,1-diphenylethylene derivative monomer containing siloxy groups / amino groups is in the range of 0.5%-10%, the mass percentage of the combined styrene content is in the range of 5%-55%, and the rest is butadiene. The number average molecular weight of the multifunctional solution-polymerized styrene-butadiene rubber containing siloxy groups / amino groups at the chain end and in the chain is in the range of 5×10 4 -80×10 4 g / mol; the multifunctional solution-polymerized styrene-butadiene rubber containing siloxy groups / amino groups in the chain end chain is a random structure, a gradient structure or a block structure, and the 1,1-diphenylethylene derivative containing siloxy groups / amino groups in the chain end chain of the multifunctional solution-polymerized styrene-butadiene rubber is evenly distributed or gradiently distributed. However, this technology mainly relies on the reaction of 1,1-diphenylethylene (DPE) with different functionalizing agents to obtain functionalized monomers containing different functional groups, and then adds them to continue the reaction after the reaction of styrene-butadiene to achieve the preparation of solution-polymerized styrene-butadiene rubber containing two functional groups. The preparation process is relatively complicated. In addition, the functionalizing agents in this technology need to be prepared in advance, the cost is high, and it is impossible to prepare on a large scale. The possibility of application in large-scale industrial devices is low, and it is limited to laboratory research. The preparation efficiency of the functionalizing agents used in this technology is too low and the separation is too difficult.

[0013] CN 109880198 A discloses a green tire tread rubber for a passenger car. The rubber material adopts trans-1,4-butadiene-isoprene copolymer rubber TBIR, solution polymerized styrene-butadiene rubber SSBR and cis-butadiene rubber BR as base rubbers. The SSBR / BR / TBIR mixed rubber formula consists of the following components by weight: 40-90 parts of solution polymerized styrene-butadiene rubber SSBR; 5-30 parts of cis-butadiene rubber BR; 5-30 parts of trans-1,4-butadiene-isoprene copolymer rubber TBIR; 0-34 parts of environmentally friendly aromatic oil; 0-105 parts of carbon black; 0-105 parts of white carbon black; 0-5 parts of white carbon black dispersant; 0-15 parts of silane coupling agent; 0.3-5 parts of accelerator; 0.2-3 parts of sulfur; 1-4.5 parts of zinc oxide; 1-9 parts of stearic acid; 0-9 parts of paraffin wax; and 1-3 parts of antioxidant. However, this technology mainly uses homemade trans-butylene rubber and purchased siloxane-functionalized SSBR to mix and vulcanize to prepare vulcanized rubber, and the focus is on the structural regulation and processing technology of homemade trans-butylene rubber. Siloxane-functionalized SSBR is prepared by connecting the end of butadiene to a reagent containing siloxane, and is a monofunctional polymer.

[0014] CN 108084345 A discloses a difunctionalized butadiene styrene polymer, the general formula of which is: (AmPR1) x Si(OR2) y , wherein Am is an aromatic amine group, R1 and R2 are alkyl groups with 1-10 carbon atoms, R3 is an alkyl group or an aryl group with 1-10 carbon atoms, P is a copolymer of butadiene and styrene, x=1-3, y=1-3, z=0-2, and x+y+z=4. However, this technology improves the performance of the vulcanized rubber by the interaction between the introduced functional groups and the fillers (carbon black / white carbon black). The linear structure is the main structure before and after functionalization, and the molecular weight and molecular structure are basically unchanged. Moreover, due to the limitation of the functionalized initiator and the unclear mechanism of the post-processing process, it has only remained in the laboratory stage and has not yet been used in industrial production.

[0015] CN 106008864 A discloses a method for synthesizing end-functionalized rubber with high end-capping efficiency by using negative ion technology. First, in a hydrocarbon solvent, a polar organic compound is used as a regulator and an organic lithium is used as an initiator to initiate a negative ion polymerization reaction of conjugated diene or monovinyl aromatic hydrocarbon to generate an active polymer. Secondly, the active polymer is reacted with a diphenylethylene capping agent to obtain a capped active polymer. Thirdly, the capped active polymer is subjected to an end-capping reaction with a novel siloxane-containing aromatic imine end-capping agent to prepare a functionalized rubber with a silanoxy-amine end group. Finally, the synthesized end-functionalized rubber is mixed with a reinforcing agent, a vulcanizing agent, an accelerator and other compounding agents to prepare a rubber composite material, and the rubber composite material with low rolling resistance, high anti-slip properties and the like is obtained by vulcanization. However, this technology lies in the preparation of advanced butadiene polymer, which is then reacted with a diphenylethylene capping agent to obtain a capping active polymer, and the product is then capped with a functionalizing agent to prepare a functionalized rubber. The linear structure is dominant before and after functionalization, and the molecular weight and molecular structure remain essentially unchanged.

[0016] CN 114867778 A discloses a rubber composition comprising a rubber component, carbon black, and silicon dioxide, wherein the CTAB adsorption specific surface area of ​​the silicon dioxide is 250 m 2 / g or more; the diameter of the aggregate morphology (DCPS) and the primary particle size (DI) of the silica measured by disc centrifugal particle size analysis meet: 700 ≥ D CPS 3 / D I 3 ≥300; the rubber component comprises at least one selected from natural rubber and polyisoprene rubber, and at least one selected from modified butadiene rubber and modified styrene butadiene rubber; the mass content of the carbon black is 70% or more relative to the total mass content of the carbon black and the silica; and the at least one selected from modified butadiene rubber and modified styrene butadiene rubber is modified by at least one selected from the group consisting of the following hydrocarbyl silane compound represented by formula (IV), the hydrocarbyl silane compound represented by formula (V), the hydrocarbyl silane compound represented by formula (III), the coupling agent represented by formula (VI), the coupling agent represented by formula (VII), the amino lithium represented by formula (VIII), and vinyl pyridine. However, the technology relates to the modifying agent of SSBR on the one hand, and the modification and process description of filler silica on the other hand. Among them, the functionalizing agent also involves two functional groups, N and Si-OR.

[0017] The prior art basically uses functionalized initiators or end-capping agents to prepare single-end functionalized SSBR, and its performance varies. In addition, its effect on pure white carbon black system is not obvious. Therefore, it is necessary to provide a dual-end multifunctionalized solution-polymerized styrene-butadiene rubber. Summary of the invention

[0018] In order to solve the above technical problems, the present invention introduces different polar functional groups at both ends of the main chain of solution-polymerized styrene-butadiene rubber through a functionalized initiator and a terminal grafting method to prepare a double-ended multifunctional solution-polymerized styrene-butadiene rubber. The introduction of these groups realizes the transformation of the molecular polarity from hydrophobic to hydrophilic, thereby increasing the interfacial compatibility of SSBR and white carbon black, which can effectively improve the dispersibility of solution-polymerized styrene-butadiene rubber in fillers, improve the comprehensive mechanical properties of SSBR vulcanizates, and be applied to the fields of high-performance green tires and new energy vehicle tires.

[0019] To achieve the above object, the present invention provides a double-terminal multifunctional solution-polymerized styrene-butadiene rubber.

[0020] The structure of the double-ended multifunctional solution-polymerized styrene-butadiene rubber is shown in the following formula (1):

[0021]

[0022] wherein z and m are the same or different and are independently selected from integers between 1 and 10; R6, R7, and R8 are the same or different and are independently selected from linear alkyl, cyclic alkyl, phenyl, active hydrogen, hydroxyl, or alkoxy with 1 to 10 carbon atoms; R9, R 10 The same or different, each independently selected from phenyl, active hydrogen, hydroxyl or alkoxy.

[0023] In the dual-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention, preferably, z and m are the same or different and are independently selected from integers between 1-5.

[0024] In the double-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention, preferably, R6, R7, and R8 are the same or different, and are independently selected from CH3, OCH3, CH2CH3, OCH2CH3 or CH2CH2CH3.

[0025] In the double-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention, preferably, R7 and R8 are the same.

[0026] The double-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention preferably has R9, R 10 The same or different, each independently selected from active hydrogen, hydroxyl, phenyl, OCH3 or OCH2CH3.

[0027] The double-ended multifunctional solution-polymerized styrene-butadiene rubber of the present invention is preferably a solution-polymerized styrene-butadiene random copolymer, wherein the styrene and butadiene monomer units are randomly distributed on the polymer main chain; the molecular weight of the copolymer is 5000-500000, the styrene content is 10-40wt%, the vinyl content of the butadiene unit is 20-70wt%, and the content of functional groups in the polymer is 0.1-5wt% of the weight of the solution-polymerized styrene-butadiene rubber.

[0028] The double-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention preferably has a molecular weight of the copolymer of 100,000-200,000.

[0029] The invention also provides a composite material formed by double-end multifunctional solution-polymerized styrene-butadiene rubber and white carbon black.

[0030] The present invention further provides a method for preparing a double-ended multifunctional solution-polymerized styrene-butadiene rubber, the preparation method comprising the following steps:

[0031] (1) adding a functionalized initiating reagent to react with the initiator under an inert gas atmosphere to obtain a functionalized initiator;

[0032] (2) adding a solvent, styrene, butadiene, and an activator to a reactor in sequence, raising the temperature, and adding the functionalized initiator obtained in step (1) to carry out a polymerization reaction to obtain a random SSBR segment;

[0033] (3) adding a functionalized end-capping agent to the random chain segments of SSBR obtained in step (2) and reacting the mixture to obtain a double-terminal multifunctionalized solution-polymerized styrene-butadiene rubber;

[0034] Wherein, the structure of the functionalized initiator is shown in the following formula (2):

[0035]

[0036] The structure of the functionalized end-capping agent is shown in the following formula (3):

[0037]

[0038] wherein z and m are the same or different and are independently selected from integers between 1 and 10; R6, R7, and R8 are the same or different and are independently selected from linear alkyl, cyclic alkyl, phenyl, active hydrogen or alkoxy with 1 to 10 carbon atoms; R9, R 10 The same or different, each independently selected from phenyl, active hydrogen, hydroxyl or alkoxy.

[0039] In the method for preparing the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, in step (1), the molar ratio of the functionalized initiating agent to the initiator is 0.05-5.0, preferably 0.1-2.

[0040] In the preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, in step (2), the polymerization reaction is carried out in an oxygen-free, water-free, inert gas environment, which belongs to solution polymerization.

[0041] The method for preparing the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention comprises the solvent comprising at least one of aromatic hydrocarbons, aliphatic alkanes and cycloalkanes.

[0042] Preferably, the aromatic hydrocarbon includes at least one of benzene, toluene and ethylbenzene.

[0043] Preferably, the aliphatic alkane includes at least one of pentane, hexane, heptane and octane.

[0044] Preferably, the cycloalkane includes at least one of cyclopentane and cyclohexane.

[0045] In the preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, the added amount of the solvent is 300-1000wt% of the total weight of styrene and butadiene monomers.

[0046] The method for preparing the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention comprises the following steps: the initiator is at least one of n-butyl lithium, sec-butyl lithium, tert-butyl lithium and hexyl lithium.

[0047] In the preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, the amount of the initiator used is 0.2-3 mmol per 100 grams of total monomers, and n-butyl lithium is preferred.

[0048] The preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, wherein the activator is a nitrogen-, oxygen- and other heterocyclic organic compound with a certain polarity, and is selected from at least one of tetrahydrofuran, ethyl tetrahydrofurfuryl ether, tetramethyl divinyl diamine, tetrahydrofuran methanol and diethylene glycol dimethyl ether (2G).

[0049] The dosage of initiator is determined by the monomer content and the molecular weight of the random chain segment of SSBR, and the dosage of activator is determined by the type of activator (polarity) and the content of side groups. It mainly adjusts the reactivity ratio of the two monomers in the polymerization reaction and the microstructure of butadiene to ensure that butadiene and styrene are random copolymers.

[0050] In the preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, the added amount of the activator is 20-2000wt% of the initiator.

[0051] The preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention comprises the following steps: in step (1), the reaction temperature is 0-40° C., preferably 20-30° C., and the reaction time is 0-60 min., preferably 5-30 min.

[0052] The preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, in step (2), the polymerization reaction temperature is 40-100°C, preferably 40-60°C, the pressure is 0.1-0.60MPa, preferably 0.2-0.4MPa, and the time is 30-90min, preferably 30-60min. At this time, the monomer conversion rate reaches 100%.

[0053] In the preparation method of the double-end multifunctional solution-polymerized styrene-butadiene rubber of the present invention, in step (3), the reaction temperature is 40-100° C. and the reaction time is 10-30 minutes.

[0054] The activator can adjust the vinyl content of butadiene, adjust the reactivity ratio of styrene and butadiene, and make the two copolymerize randomly, and at the same time can make the alkyl lithium initiator produce polarization or solvation effect, reduce its association degree, and increase the initiation reaction speed of the initiator such as n-butyl lithium. The present invention does not particularly limit the source of the activator, which can be commercially available or prepared by conventional methods in the art.

[0055] In one embodiment, after the preparation of the double-end multifunctional solution-polymerized styrene-butadiene rubber, an antioxidant may be added to improve its aging resistance. Specifically, the following method may be used: the polymer solution obtained after the preparation of the double-end multifunctional solution-polymerized styrene-butadiene rubber is transferred to a chemical treatment kettle after the polymerization is completed, an antioxidant is added, and then the polymer is separated from the solution to obtain the modified double-end multifunctional solution-polymerized styrene-butadiene rubber. The antioxidant is, for example but not limited to, one or more of 1520L, 1076, 1010, 264, TNPP, and triisopropanolamine, and the amount of the antioxidant added is 0.5-5wt%, preferably 0.5-2wt%. The separation of the polymer from the solution may be carried out by a conventional steam stripping condensation method, or by a devolatilization screw extruder.

[0056] The preparation method of the double-terminal multifunctional solution-polymerized styrene-butadiene rubber of the present invention can also be described in detail as follows:

[0057] (1) The preparation method of the functionalized initiator is as follows: under argon protection, a calculated amount of a functionalized initiating agent and an initiator are added to a 100 mL two-necked bottle, and the functionalized initiator is prepared by stirring the reaction at a certain temperature. The generated functionalized initiator has good solubility in cyclopentane and no particles are generated. The reaction temperature is 0-40° C., preferably 20-30° C., the functionalized agent / initiator = 0.05-5.0, preferably 0.1-2, and the reaction time is 0-60 min, preferably 5-30 min.

[0058] (2) Preparation method of double-end multifunctional SSBR: In a polymerization kettle that is evacuated and replaced with argon, add solvent, styrene, butadiene, and activator in sequence, start hot water circulation, and when the polymerization system reaches a predetermined temperature, stop hot water circulation, add functionalized initiator, initiate polymerization reaction for a certain period of time, and form SSBR random segments. The reaction temperature is 40-100°C, preferably 40-60°C, the reaction pressure is 0.1-0.60MPa, preferably 0.2-0.4MPa, and the reaction time is 30-90min, preferably 30-60min. At this time, the monomer conversion rate reaches 100%. The amount of initiator is determined by the monomer content and the molecular weight of the SSBR segment, and the amount of activator is determined by the type of activator (polarity) and the side group content, which mainly adjusts the reactivity ratio of the two monomers in the polymerization reaction and the microstructure of butadiene to ensure that butadiene and styrene are random copolymers. The combined styrene content in the SSBR chain segment is 10-40wt%, and the vinyl content of the butadiene unit is 20-70wt%. Then, a functionalized end-capping agent is added, and the reaction temperature is maintained at 40-100° C. for 10-30 minutes to form a multifunctional SSBR with amino-siloxane groups at both ends.

[0059] After the double-end multifunctionalized solution-polymerized styrene-butadiene rubber of the present invention introduces functionalized groups at both ends, the types and quantities of functional groups are qualitatively improved, which can truly enhance the polarity of the solution-polymerized styrene-butadiene rubber, thereby enhancing the interaction between the solution-polymerized styrene-butadiene rubber and the filler, and further effectively promote the dispersion of the filler in the solution-polymerized styrene-butadiene rubber. The special tire for new energy vehicles developed using the composite material formed by the solution-polymerized styrene-butadiene rubber and the filler of the present invention has excellent performances such as longer cruising range, excellent high-speed control, and durability. Compared with traditional fuel passenger car tires, it has low rolling resistance, low fuel consumption, excellent handling stability, shorter braking distance, better wear resistance, and can be refurbished multiple times. Compared with traditional tires, it highlights the advantages of environmental protection, energy saving, safety, new processes, and new materials. Compared with single-end functionalized SSBR, the double-end multifunctionalized solution-polymerized styrene-butadiene rubber of the present invention can further reduce the number of active ends, thereby reducing internal friction, to improve the wear resistance and anti-slip performance of the solution-polymerized styrene-butadiene rubber, and reduce rolling resistance.

[0060] The functionalized initiator and the functionalized end-capping agent used in the double-end multifunctionalized solution-polymerized styrene butadiene rubber of the present invention have low cost and are easy to prepare. Not only can a larger number and types of functional groups be grafted into the double-end multifunctionalized solution-polymerized styrene butadiene rubber, but the process is simple and the product is suitable for large-scale industrial production and can be used for preparing high-performance green tires and electric vehicle tire treads.

[0061] The preparation method of the present invention adopts an anionic solution polymerization method to synthesize a double-terminal multifunctional solution-polymerized styrene-butadiene rubber, and has the advantages of low cost, simplicity, high activity, high stability, etc. The process flow is simple and easy, saving cost and time, and is conducive to intermittent or continuous production of industrial devices. The preparation method of the present invention is simple and easy, with mild conditions, and can be adapted to existing anionic solution polymerization devices, and can also be satisfied with newly built anionic solution polymerization devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 The double-terminal multifunctional SSBR of Example 1 1 H-NMR spectrum. DETAILED DESCRIPTION

[0063] The following examples are selected to further illustrate the method of the present invention, but should not be limited thereto in practical applications. This example is used to illustrate the double-terminal multifunctionalized solution-polymerized styrene-butadiene rubber and its preparation method and vulcanized rubber provided by the present invention.

[0064] The polymer characterization and rubber performance evaluation in the examples were performed using the following instruments: US Varian INOVA 400 NMR nuclear magnetic resonance 1 H-NMR was used to qualitatively and quantitatively analyze the composition sequence distribution and microstructure of the copolymers. TDA302 gel permeation chromatography (GPC) produced by Viscotek, USA, was used to analyze the molecular weight and molecular weight distribution of the copolymers. The mechanical properties were tested using a 4465 universal material testing machine produced by NSTRON, USA. The dynamic mechanical properties were tested using a DMAQ800 / RSA3 dynamic thermomechanical analyzer from USA.

[0065] (1) Mechanical properties test: tensile strength and elongation at break were tested in accordance with GB / T528-2009, and tear strength test was tested in accordance with GB / T529-2008.

[0066] (2) Shore A hardness test: The test shall be conducted in accordance with the method specified in GB / T23651-2009.

[0067] (3) Dynamic mechanical properties test: The dynamic mechanical properties test was carried out using the American DMA Q800 / RSA3 dynamic thermomechanical analyzer.

[0068] Example 1

[0069] Under argon protection, 5.3mmol n-butyl lithium and 2.6mmol hexamethyleneimine were added to a 100mL two-necked bottle, and the reaction was stirred at 30℃ for 10min to obtain a functionalized initiator. In a 10L polymerization kettle with a jacket, argon was passed through the system to replace it three times. 5109g hexane, 200g styrene, 600g butadiene, and 0.62g ethyl tetrahydrofurfuryl ether were added to the polymerization kettle, the temperature was raised to 50℃, and the functionalized initiator was added. The polymerization system was naturally heated to 50℃. After 1 hour of polymerization, the conversion rate reached 100%, and an α-amino functionalized butadiene polymer with a number average molecular weight of 150,000 and a molecular weight distribution of 1.1 was obtained; then the temperature was raised to 60℃, and 5.3mmol functionalized end-capping reagent (in formula (1), m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl) into the polymerization kettle, and continue to react for 0.5 hours to obtain double-terminal multifunctional SSBR. Then, antioxidant is added, the material is discharged, and the rubber solution is coagulated by wet method, dried and used for standby.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that hexamethyleneimine is not added, but butyl lithium is directly used to synthesize styrene-butadiene random polymer, and finally an unfunctionalized styrene-butadiene glue solution is obtained. The glue solution is wet coagulated and dried.

[0072] Example 2

[0073] The method of Example 1 was followed, except that "5.3 mmol hexamethyleneimine" was used to replace "2.6 mmol hexamethyleneimine" to obtain a double-terminal multifunctional SSBR.

[0074] Example 3

[0075] The method of Example 1 was followed, except that "7.9 mmol hexamethyleneimine" was used to replace "2.6 mmol hexamethyleneimine" to obtain a double-terminal multifunctional SSBR.

[0076] Example 4

[0077] The method of Example 2 was followed, except that "stirring and reacting at 30° C. for 5 min" was used instead of "stirring and reacting at 30° C. for 10 min", to obtain a double-end multifunctional SSBR.

[0078] Example 5

[0079] The method of Example 2 was followed, except that “stirring and reacting at 30° C. for 2 min” was used instead of “stirring and reacting at 30° C. for 10 min” to obtain a double-end multifunctional SSBR.

[0080] Example 6

[0081] The method of Example 1 was followed, except that "10.6 mmol hexamethyleneimine" was used to replace "2.6 mmol hexamethyleneimine" to obtain a double-terminal multifunctional SSBR.

[0082] Example 7

[0083] The method of Example 6 was followed, except that "m = 3, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 = phenyl" replaces "m = 2, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0084] Example 8

[0085] The method of Example 6 was followed, except that "m = 2, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 =OCH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0086] Example 9

[0087] The method of Example 6 was followed, except that "m = 2, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 =OCH2CH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0088] Example 10

[0089] The method of Example 6 was followed, except that "m = 1, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 =OCH2CH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0090] Embodiment 11

[0091] The method of Example 6 was followed, except that "m = 3, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10=OCH2CH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0092] Example 12

[0093] The method of Example 6 was followed, except that "m = 2, z = 2, R6 = CH3, R7 = R8 = OCH3, R9 = R 10 =OCH2CH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0094] Example 13

[0095] The method of Example 6 was followed, except that "m = 3, z = 2, R6 = H, R7 = R8 = OH, R9 = OH, R 10 =OCH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0096] Embodiment 14

[0097] The method of Example 6 was followed, except that "m = 2, z = 2, R6 = H, R7 = R8 = OH, R9 = R 10 =OH" replaces "m = 2, z = 2, R6 = CH2CH3, R7 = R8 = OCH2CH3, R9 = R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0098] Embodiment 15

[0099] The method of Example 6 was followed, except that "m = 2, z = 2, R6 = CH2CH3, R7 = H, R8 = OCH2CH3, R9 = R 10 =OCH3" replaces "m=2, z=2, R6=CH2CH3, R7=R8=OCH2CH3, R9=R 10 = phenyl", to obtain a double-terminal multifunctional SSBR.

[0100] Preparation Example 1

[0101] The double-end multifunctional SSBR obtained in Examples 1-15 and the styrene-butadiene rubber solution obtained in Comparative Example 1 were mixed and vulcanized to obtain a vulcanized rubber, and the preparation process thereof is as follows:

[0102] 100 parts by weight of double-ended multifunctional SSBR or styrene-butadiene rubber solution, 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 2 parts by weight of vulcanization accelerator DM, 2 parts by weight of vulcanization accelerator D0.6, 1.5 parts by weight of antioxidant RD, 6 parts by weight of Si-69, 70 parts by weight of white carbon black SiO2, 5 parts of carbon black N330 and 2 parts by weight of sulfur were added into an open mill, and then mixed in an internal mixer for 15 minutes according to a certain sequence and process, and then the obtained mixed rubber was vulcanized at a certain temperature, pressure and time using a flat vulcanizer to obtain vulcanized rubbers J1-J15 and C1.

[0103] Table 1 Vulcanized rubber performance test results

[0104]

[0105]

[0106] The data of all test cases are shown in Table 1. From the test results of C1 and J1, it can be seen that the vulcanized rubber obtained by the double-end functionalized styrene-butadiene copolymer prepared by the method provided by the present invention as a rubber-based rubber has a significant improvement in performance compared to unfunctionalized SSBR, and has very excellent mechanical properties, high wet-slip resistance and low rolling resistance and low wear. From the test results of J2-J5, it can be seen that with the increase in the amount of functionalized initiator added, the dynamic mechanical properties of the vulcanized rubber are significantly improved, but when it is further increased, the performance does not change greatly. From the test results of J1, J7, J8, J9, J10, J11, and J12, it can be seen that when the number of alkyl groups spaced between the amine group and the siloxane group is more, the degree of hydrolysis of siloxane is more difficult, which means that more siloxanes will be involved in the interaction with the filler during processing, which mainly brings about a reduction in rolling resistance, and inevitably leads to fluctuations in other properties, which conforms to the law of change of the magic triangle. Similarly, although the increase in the number of alkyl groups in the alkoxy group will theoretically reduce the degree of siloxane hydrolysis, in reality the change in performance is not significant and is basically at the same level. The test results of J13, J14, and J15 show that the direct introduction of hydroxyl groups will reduce the steps of siloxane hydrolysis, hydrogen bond with fillers, and improve wear resistance, but the reduction of siloxane will inevitably increase the rolling resistance slightly.

[0107] In general, the double-terminal multifunctionalized solution-polymerized styrene-butadiene rubber prepared by the functionalized initiator and the functionalized end-capping reagent provided by the present invention is a new type of green tread rubber with excellent performance and great industrial application prospects.

[0108] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A double-terminal multifunctional solution-polymerized styrene-butadiene rubber, characterized in that: The structure of the double-ended multifunctional solution-polymerized styrene-butadiene rubber is shown in the following formula (1): wherein z and m are the same or different and are independently selected from integers between 1 and 10; R6, R7, and R8 are the same or different and are independently selected from linear alkyl, cyclic alkyl, phenyl, active hydrogen, hydroxyl, or alkoxy with 1 to 10 carbon atoms; R9, R 10 The same or different, each independently selected from phenyl, active hydrogen, hydroxyl or alkoxy.

2. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that: z and m are the same or different, and are each independently selected from an integer between 1 and 5.

3. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that: R6, R7, R8 are the same or different, and are each independently selected from CH3, OCH3, CH2CH3, OCH2CH3 or CH2CH2CH3.

4. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that: R7 and R8 are the same.

5. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that: R9, R 10 The same or different, each independently selected from active hydrogen, hydroxyl, phenyl, OCH3 or OCH2CH3.

6. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that: The solution polymerized styrene butadiene rubber is a solution polymerized styrene and butadiene random copolymer, wherein the styrene and butadiene monomer units are randomly distributed on the polymer main chain; the molecular weight of the copolymer is 5000-500000, the styrene content is 10-40wt%, the vinyl content of the butadiene unit is 20-70wt%, and the content of functional groups in the polymer is 0.1-5wt% of the weight of the solution polymerized styrene butadiene rubber.

7. The double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to claim 6, characterized in that: The molecular weight of the copolymer is 100,000-200,000.

8. A composite material formed by the double-terminal multifunctional solution-polymerized styrene-butadiene rubber according to any one of claims 1 to 7 and white carbon black.

9. A method for preparing a double-ended multifunctional solution-polymerized styrene-butadiene rubber, characterized in that: The following steps are involved: (1) adding a functionalized initiating reagent to react with the initiator under an inert gas atmosphere to obtain a functionalized initiator; (2) adding a solvent, styrene, butadiene, and an activator to a reactor in sequence, raising the temperature, and adding the functionalized initiator obtained in step (1) to carry out a polymerization reaction to obtain a random SSBR segment; (3) adding a functionalized end-capping agent to the random chain segments of SSBR obtained in step (2) and reacting the mixture to obtain a double-terminal multifunctionalized solution-polymerized styrene-butadiene rubber; Wherein, the structure of the functionalized initiator is shown in the following formula (2): The structure of the functionalized end-capping agent is shown in the following formula (3): wherein z and m are the same or different and are independently selected from integers between 1 and 10; R6, R7, and R8 are the same or different and are independently selected from linear alkyl, cyclic alkyl, phenyl, active hydrogen or alkoxy with 1 to 10 carbon atoms; R9, R 10 The same or different, each independently selected from phenyl, active hydrogen, hydroxyl or alkoxy.

10. The preparation method according to claim 9, characterized in that: In step (1), the molar ratio of the functionalized initiating agent to the initiator is 0.05-5.

0.

11. The preparation method according to claim 9, characterized in that: In step (2), the polymerization reaction is carried out in an oxygen-free, water-free, inert gas environment.

12. The preparation method according to claim 9, characterized in that: The solvent includes at least one of aromatic hydrocarbons, aliphatic alkanes, and cycloalkanes; The aromatic hydrocarbons include at least one of benzene, toluene and ethylbenzene; The aliphatic alkane includes at least one of pentane, hexane, heptane and octane; The cycloalkane includes at least one of cyclopentane and cyclohexane; The amount of the solvent added is 300-1000wt% of the total weight of styrene and butadiene monomers.

13. The preparation method according to claim 9, characterized in that: The initiator is at least one of n-butyl lithium, sec-butyl lithium, tert-butyl lithium and hexyl lithium; The initiator is used in an amount of 0.2-3 mmol per 100 g of total monomers.

14. The preparation method according to claim 9, characterized in that: The activator is selected from at least one of tetrahydrofuran, ethyl tetrahydrofurfuryl ether, tetramethyl divinyl diamine, tetrahydrofuran methanol, and diethylene glycol dimethyl ether; The added amount of the activator is 20-2000wt% of the initiator.

15. The preparation method according to claim 9, characterized in that: In step (1), the reaction temperature is 0-40°C, and the reaction time is 0-60min; In step (2), the polymerization reaction is carried out at a temperature of 40-100° C., a pressure of 0.1-0.60 MPa, and a time of 30-90 min; In step (3), the reaction temperature is 40-100°C and the reaction time is 10-30 minutes.

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