In-chain functionalized solution polymerized styrene-butadiene rubber and preparation method thereof

Abstract

The invention provides in-chain functionalized solution polymerized styrene-butadiene rubber and a preparation method thereof. The method comprises the following steps: in a polymerization system, carrying out random polymerization reaction by taking alkanes as a first solvent, ethers as an active agent, butadiene, styrene and a third functional monomer as polymerization monomers and organic lithium as a first initiator to obtain an active styrene-butadiene rubber solution; adding a first terminator into the active styrene-butadiene rubber solution to terminate the random polymerization reaction to obtain a solution polymerized styrene-butadiene rubber solution; and precipitating and drying the solution polymerized styrene-butadiene rubber solution to obtain the chain functionalized solution polymerized styrene-butadiene rubber. Through random copolymerization of a third functional monomer self-made in a laboratory, styrene and butadiene, a chain of solution polymerized styrene-butadiene rubber contains an amino functional group, so that the interface bonding force between white carbon black and styrene-butadiene rubber is enhanced, and the hysteresis loss of a final tire rubber product is reduced; and high wear resistance, fatigue resistance and excellent wet skid-rolling resistance balance are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of solution-polymerized styrene-butadiene rubber, in particular to a chain-functionalized solution-polymerized styrene-butadiene rubber and a preparation method thereof. Background Art

[0002] Solution-polymerized styrene butadiene rubber is widely used in tires, shoes and other vulcanized rubber products because of its adjustable microstructure, narrow molecular weight distribution, and better vulcanization performance, processing performance and product performance than natural rubber. With the increasing prominence of environmental issues such as "carbon emissions" and shortage of oil resources, the automotive industry has higher and higher requirements for energy saving of tires. Relevant research shows that the energy consumption generated by overcoming the rolling resistance of tires during driving accounts for 30% of the total energy consumption.

[0003] At present, the "solution polymerized styrene butadiene rubber + white carbon black" system is the standard for low rolling resistance tread rubber. It has become an industry consensus to prepare tread rubber by reinforcing SSBR with white carbon black to solve the "magic triangle" problem. However, white carbon black with a large amount of silanol on the surface has poor dispersion in styrene butadiene rubber. It is still a key problem to overcome to achieve uniform dispersion of polar white carbon black in the rubber substrate by regulating the interfacial bonding force between white carbon black and styrene butadiene rubber.

[0004] In order to improve the interfacial bonding force between silica and styrene-butadiene rubber and achieve uniform dispersion of polar silica in the rubber matrix, silane coupling agents are added during the rubber mixing process, and branched coupling, end-capping modification and other technologies are used to improve the processing performance and dynamic properties of styrene-butadiene rubber. The above methods can introduce polar functional groups such as amino groups and siloxane groups at the ends of the styrene-butadiene rubber molecules, and the end-capping modification rate reaches more than 80%, realizing the chain end modification of solution-polymerized styrene-butadiene rubber. However, the above methods can only introduce polar functional groups at the ends of the molecular chains. Since the number of macromolecular chain ends of solution-polymerized styrene-butadiene rubber is very limited, the chain end modification technology has a very limited effect on improving the interfacial bonding force between fillers and polymers. Summary of the invention

[0005] The present invention aims to solve the above-mentioned problem by randomly copolymerizing a third functional monomer carrying an amino functional group with styrene and butadiene, thereby introducing an amino functional group into the molecular chain of the solution-polymerized styrene-butadiene rubber to enhance the interfacial bonding force between white carbon black and styrene-butadiene rubber, reduce the hysteresis loss of the final tire rubber product, and impart it with high wear resistance, fatigue resistance and excellent wet skid-rolling resistance balance.

[0006] To achieve the above object, the present invention provides a method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber, the method comprising the following steps: S10, in a polymerization system, using alkanes as the first solvent, ethers as the activator, butadiene, styrene, and the third functional monomer as the polymerization monomers, and organic lithium as the first initiator, to perform a random polymerization reaction to obtain an active butadiene-styrene rubber solution; S20, adding a first terminator to the active styrene-butadiene rubber solution to terminate the random polymerization reaction to obtain a solution-polymerized styrene-butadiene rubber solution; S30, the solution polymerized styrene butadiene rubber solution is precipitated and dried to obtain the in-chain functionalized solution polymerized styrene butadiene rubber; The third functional monomer is a functional monomer containing an amino functional group obtained by polymerizing a secondary amine monomer with an olefin monomer using alkanes as the second solvent and organic lithium as the second initiator; the olefin monomer is a divinyl aromatic monomer and / or a conjugated diene monomer.

[0007] The technical effect of adopting the above technical scheme is: a third functional monomer containing an amino functional group is synthesized by using an amino-containing secondary amine and the alkenyl monomer, and then the third functional monomer containing an amino functional group, butadiene and styrene are randomly polymerized to break through the technical limitations of the chain end modification of styrene-butadiene rubber, and an amino functional group is introduced in the middle of the styrene-butadiene rubber molecular chain, which can significantly enhance the interfacial bonding force between white carbon black and styrene-butadiene rubber, thereby reducing the hysteresis loss of the final tire rubber product and giving it high wear resistance, fatigue resistance and excellent wet skid-rolling resistance balance.

[0008] Further, the secondary amine monomer is selected from one or more of dimethylamine, pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine and dodecamethyleneimine; and / or the divinyl aromatic monomer is selected from one or more of o- / m- / p-divinylbenzene, o- / m- / p-diisopropenylbenzene; and / or the conjugated diene monomer is selected from one or more of butadiene, isoprene, styrene and piperylene.

[0009] The technical effect of adopting the above technical scheme is that the secondary amine monomer is selected from one or more of dimethylamine, pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine and dodecamethyleneimine, so that the third functional monomer can carry different amino functional groups such as dimethylamine, pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine and dodecamethyleneimine; and the secondary amine monomer, divinyl aromatic monomer and conjugated diene monomer are all commonly used industrial chemicals, which have the advantages of being cheap, easily available and non-toxic.

[0010] Furthermore, the alkanes are selected from one or more of cyclopentane, cyclohexane, heptane, and octane; and / or the ethers are selected from one or more of tetrahydrofuran, tetrahydrofurfuryl ether, diethylene glycol dimethyl ether, ethyl ether, ethyl methyl ether, anisole, and diphenyl ether; and / or the organic lithium is selected from one or more of alkyl lithium, aryl lithium, arylalkyl lithium, and cycloalkyl lithium; and / or the terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds.

[0011] In any of the above technical solutions, the preparation method of the third functional monomer comprises the following steps: S11, adding the second initiator and the secondary amine monomer to the second solvent, stirring and mixing, the reaction time is 5 to 60 minutes, to obtain an amide-containing lithium compound solution; S12, adding the olefinic monomer to the second solvent, stirring and mixing at a temperature of 0 to 10° C. to obtain a homogeneous olefinic monomer solution; S13, adding the amide-containing lithium compound solution to the olefinic monomer homogeneous solution, stirring and mixing, to obtain an active third functional monomer solution; S14, adding the second terminator to the active third functional monomer solution to terminate the reaction to obtain a third functional monomer solution; S15, washing and drying the third functional monomer solution to obtain the third functional monomer.

[0012] The technical effects of adopting the above technical scheme are: the preparation principle of the third functional monomer is simple, the operation is simple, the reaction conditions are mild, the side reactions are few, and the product conversion rate is high.

[0013] Further, the molar ratio of the secondary amine monomer, the conjugated diene monomer, the divinyl aromatic monomer, the organic lithium, the terminator and the solvent is 1:(0-100):(1-5):(0.1-1):(0.1-2):(5-100); and / or The second terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds.

[0014] Furthermore, in S10, the reaction temperature of the random polymerization reaction is 0-60° C.; and / or the reaction time of the random polymerization reaction is 100-130 min.

[0015] Furthermore, the concentration of the polymerizable monomer is 5-30%; and / or the amount of the first solvent added relative to the total mass of the polymerizable monomer is 50-50000 mg / kg; and / or the amount of the first initiator added relative to the total mass of the polymerizable monomer is 100-750 mg / kg; and / or the molar ratio of the first terminator to the first initiator is 0.9-2.0; and / or the mass fraction of the mass of the styrene and the third functional monomer to the total mass of the polymerizable monomer is 5-95%; wherein the mass ratio of the third functional monomer to the styrene is (1-70):(30-99).

[0016] The technical effect of adopting the above technical solution is: by accurately limiting the addition amount of the third functional monomer, the functionalization degree and functional group site of the amino functional group in the molecular chain of the solution-polymerized styrene-butadiene rubber can be controlled and adjusted.

[0017] Furthermore, the preparation method further comprises: S40, adding an antioxidant to the polystyrene-butadiene rubber solution obtained in S20; Wherein, the antioxidant is selected from one or more of 2,6-di-tert-butyl-p-cresol, antioxidant 1076, antioxidant 1520, antioxidant 168, antioxidant 626, hindered phenol, hindered amine, and phosphate compound; and / or The antioxidant is added in an amount of 0.01-0.3%wt relative to the in-chain functionalized solution-polymerized styrene-butadiene rubber.

[0018] The technical effect of adopting the above technical solution is: by adding an antioxidant, the aging of the solution-polymerized styrene-butadiene rubber is delayed and the service life is extended.

[0019] The present invention also provides a chain-functionalized solution-polymerized styrene-butadiene rubber, which is obtained by using the preparation method of any of the above technical solutions.

[0020] The obtained chain functionalized solution polymerized styrene butadiene rubber has the following characteristics: The vinyl structural unit in the butadiene structural unit of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 6 to 90%; The number average molecular weight of the chain functionalized solution-polymerized styrene-butadiene rubber is 100,000 to 1,000,000 g / mol; The Mooney viscosity of the chain-functionalized solution-polymerized styrene-butadiene rubber is 30 to 80; The molecular weight distribution of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 1.0-2.0; The glass transition temperature of the in-chain functionalized solution-polymerized styrene-butadiene rubber is -50 to 0°C; The modification rate of the functionalized solution-polymerized styrene-butadiene rubber in the chain is greater than 90%; The nitrogen content of the chain-functionalized solution-polymerized styrene-butadiene rubber is 800-1200 mg / kg.

[0021] The technical effects of adopting the above technical scheme are: the molecular weight of the chain-functionalized solution-polymerized styrene-butadiene rubber is large and the Mooney viscosity is higher, which means that the interaction force between the molecular chains of the chain-functionalized solution-polymerized styrene-butadiene rubber is significantly higher than that of the chain end modification technology, and the modification rate is greater than 90%, which means that the reaction activity of the chain-functionalized solution-polymerized styrene-butadiene rubber modification technology is higher; the nitrogen content of the chain-functionalized solution-polymerized styrene-butadiene rubber is higher, which means that the chain-functionalized solution-polymerized styrene-butadiene rubber modification technology can give the solution-polymerized styrene-butadiene rubber a higher degree of functionalization, thereby significantly improving the interfacial bonding force between the solution-polymerized styrene-butadiene rubber and silica. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 The synthetic reaction mechanism of the third functional monomer; Figure 2 is the molecular structure of butadiene; Figure 3 is the H NMR spectrum of butadiene; Figure 4 is the molecular structure formula of p-divinylbenzene; Figure 5 This is the H NMR spectrum of divinylbenzene; Figure 6 It is the molecular structure formula of dimethylamine; Figure 7 This is the H NMR spectrum of dimethylamine; Figure 8 is the molecular structural formula of the third functional monomer obtained in Example 1; Fig. 9 This is the H NMR spectrum of the third functional monomer obtained in Example 1; Fig.10 is the molecular structure formula of pyrrolidine; Fig.11 is the H NMR spectrum of pyrrolidine; Fig.12 is the molecular structural formula of the third functional monomer obtained in Example 2; Fig.13 This is the H NMR spectrum of the third functional monomer obtained in Example 2; Fig.14 is the molecular structure formula of piperidine; Fig.15 is the piperidine H NMR spectrum; Fig.16 is the molecular structural formula of the third functional monomer obtained in Example 3; Fig.17This is the H NMR spectrum of the third functional monomer obtained in Example 3; Fig.18 It is the molecular structure formula of hexamethyleneimine; Fig.19 This is the H NMR spectrum of hexamethyleneimine; Fig. 20 is the molecular structural formula of the third functional monomer obtained in Example 4; Fig.21 This is the H NMR spectrum of the third functional monomer obtained in Example 4; Fig. 22 It is the molecular structure formula of heptamethyleneimine; Fig.23 This is the H NMR spectrum of heptamethyleneimine; Fig.24 is the molecular structural formula of the third functional monomer obtained in Example 5; Fig.25 This is the H NMR spectrum of the third functional monomer obtained in Example 5; Fig.26 It is the molecular structure formula of dodecamethyleneimine; Fig. 27 This is the H NMR spectrum of dodecamethyleneimine; Fig.28 is the molecular structural formula of the third functional monomer obtained in Example 6; Fig.29 This is the H NMR spectrum of the third functional monomer obtained in Example 6; Fig.30 The reaction mechanism of the third functional monomer obtained in Example 7; Fig.31 This is the reaction mechanism of chain functionalized solution polymerized styrene-butadiene rubber. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Solution-polymerized styrene butadiene rubber is widely used in tires, shoes and other vulcanized rubber products because of its adjustable microstructure, narrow molecular weight distribution, and better vulcanization performance, processing performance and product performance than natural rubber. With the increasing prominence of environmental issues such as "carbon emissions" and shortage of oil resources, the automotive industry has higher and higher requirements for energy saving of tires. Relevant research shows that the energy consumption generated by overcoming the rolling resistance of tires during driving accounts for 30% of the total energy consumption.

[0025] At present, the "solution polymerized styrene butadiene rubber + white carbon black" system is the standard for low rolling resistance tread rubber. It has become an industry consensus to prepare tread rubber by reinforcing SSBR with white carbon black to solve the "magic triangle" problem. However, white carbon black with a large amount of silanol on the surface has poor dispersion in styrene butadiene rubber. It is still a key problem to overcome to achieve uniform dispersion of polar white carbon black in the rubber substrate by regulating the interfacial bonding force between white carbon black and styrene butadiene rubber.

[0026] In order to improve the interfacial bonding strength between silica and styrene-butadiene rubber and achieve uniform dispersion of polar silica in the rubber matrix, silane coupling agents such as bis-[3-(triethoxysilyl)propyl]-tetrasulfide and γ-mercaptopropyltrimethoxysilane are added during the rubber mixing process, or the above-mentioned silane coupling agents are used to modify the surface of silica, and the interfacial properties of silica are regulated to achieve good interfacial bonding between silica and styrene-butadiene rubber. However, the addition of silane coupling agents during the mixing process not only requires a large amount of silane coupling agents, but also the final vulcanized product is prone to the problem of silane coupling agent "migration", resulting in poor rubber performance; so this method has no obvious effect on improving the interfacial bonding strength between silica and styrene-butadiene rubber. In addition, the pretreatment process of surface modification of silica using silane coupling agents is relatively complicated, the modification effect is not good, and the effect of improving the interfacial bonding strength between silica and styrene-butadiene rubber is also very limited.

[0027] In addition, branched coupling, end-capping modification and other technologies are used to improve the processing performance and dynamic performance of styrene-butadiene rubber. For example, LG Chemical Co., Ltd. of South Korea uses cyclohexylimide, n-butyl lithium and conjugated dienes (such as butadiene) to react to prepare amino-functionalized initiators in its patent CN107810209B, which are used to initiate random copolymerization of butadiene and styrene to prepare chain-end amino-functionalized solution-polymerized styrene-butadiene rubber; the invention also uses vinyl-N,N-dimethylbenzylamine compounds to react with butyl lithium to prepare amino-functionalized anionic initiators, which can also prepare chain-end amino-functionalized solution-polymerized styrene-butadiene rubber.

[0028] Asahi Kasei of Japan uses alkyl lithium initiator to initiate random copolymerization of butadiene and styrene in its patent CN105175582B, and adds 1-[3-(triethoxysilyl)propyl]-4-methylpiperazine, 1-[3-(triethoxysilyl)propyl]-4-(trimethylsilyl)piperazine, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2-[3-(trimethoxysilyl)propyl]-1,3-dimethylimidazolidine, [3-(dimethylamino)propyl]trimethoxysilane, and 1,3-dimethyl-2-imidazolidinone as end-capping agents, which can introduce amino and / or siloxane groups at the ends of styrene-butadiene rubber, and the end-capping modification rate reaches more than 80%.

[0029] CN102482359A also uses a piperazine compound containing a siloxane substituent as a capping agent for styrene-butadiene rubber; CN107250172B and CN109476778B use silazane compounds as capping agents for styrene-butadiene rubber; CN107835752A uses 3-isocyanate propyltrimethoxysilane to react with terminal hydroxyl polybutadiene to prepare silane-modified polybutadiene rubber for tire components.

[0030] The above methods can introduce polar functional groups such as amino groups and siloxane groups into the molecular chain ends of solution-polymerized styrene-butadiene rubber, and the end-capping modification rate can reach more than 80%, thus realizing the chain-end modification of solution-polymerized styrene-butadiene rubber. However, the above methods only introduce polar functional groups into the molecular chain ends. Since the number of macromolecular chain ends of solution-polymerized styrene-butadiene rubber is very limited, the chain-end modification technology has a very limited effect on improving the interfacial bonding force between fillers and polymers. Moreover, the above-mentioned end-capping agents have complex structures and are difficult to obtain; they are expensive; they have obvious odors and are highly toxic; they are not highly reactive, require large amounts of addition, and have many side reactions; and the range of polar functional groups available is small, generally dominated by tertiary amine groups and siloxane groups.

[0031] Therefore, the present invention develops a chain modification technology for solution-polymerized styrene-butadiene rubber, which utilizes a third functional monomer carrying an amino functional group to randomly copolymerize with styrene and butadiene, thereby introducing an amino functional group into the molecular chain of the solution-polymerized styrene-butadiene rubber to enhance the interfacial bonding force between silica and styrene-butadiene rubber, reduce the hysteresis loss of the final tire rubber product, and impart it with high wear resistance, fatigue resistance and excellent wet skid-rolling resistance balance.

[0032] To achieve the above object, the present invention provides a method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber, the method comprising the following steps: S10, in a polymerization system, using alkanes as a first solvent, ethers as an activator, butadiene, styrene, and a third functional monomer as polymerization monomers, and organic lithium as a first initiator, to perform a random polymerization reaction to obtain an active styrene-butadiene latex; S20, adding a first terminator to the active styrene butadiene rubber latex to terminate the random polymerization reaction to obtain a solution polymerized styrene butadiene rubber solution; S30, the solution polymerized styrene butadiene rubber solution is precipitated and dried to obtain the in-chain functionalized solution polymerized styrene butadiene rubber; The third functional monomer is a functional monomer containing an amino functional group obtained by polymerizing a secondary amine monomer with an olefin monomer using alkanes as the second solvent and organic lithium as the second initiator; the olefin monomer is a divinyl aromatic monomer and / or a conjugated diene monomer.

[0033] Further, the secondary amine monomer is selected from one or more of dimethylamine, pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine and dodecamethyleneimine, wherein hexamethyleneimine can be 3,3,5-trimethylhexamethyleneimine; and / or the divinyl aromatic monomer is selected from one or more of o- / m- / p-divinylbenzene, o- / m- / p-diisopropenylbenzene; and / or the conjugated diene monomer is selected from one or more of butadiene, isoprene, styrene and isoprene.

[0034] Further, the alkanes are selected from one or more of cyclopentane, cyclohexane, heptane, and octane, preferably cyclohexane; and / or the ethers are selected from one or more of tetrahydrofuran, tetrahydrofurfuryl ether, diethylene glycol dimethyl ether, ethyl ether, ethyl methyl ether, anisole, and diphenyl ether, preferably tetrahydrofuran; and / or the organic lithium is selected from one or more of alkyl lithium, aryl lithium, arylalkyl lithium, and cycloalkyl lithium, preferably alkyl lithium, and the alkyl lithium is preferably n-butyl lithium; and / or the first terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds, preferably water.

[0035] In any of the above technical solutions, the preparation method of the third functional monomer comprises the following steps: S11, adding the second initiator and the secondary amine monomer to the second solvent, stirring and mixing, the reaction time is 5 to 60 minutes, to obtain an amide-containing lithium compound solution; S12, adding the olefinic monomer to the second solvent, stirring and mixing at a temperature of 0 to 10° C. to obtain a homogeneous olefinic monomer solution; S13, adding the amide-containing lithium compound solution to the olefinic monomer homogeneous solution, stirring and mixing, to obtain an active third functional monomer solution; S14, adding the second terminator to the active third functional monomer solution to terminate the reaction to obtain a third functional monomer solution; S15, washing and drying the third functional monomer solution to obtain the third functional monomer.

[0036] Furthermore, the molar ratio of the secondary amine monomer, the conjugated diene monomer, the divinyl aromatic monomer, the second initiator, the second terminator and the second solvent is 1:(0-100):(1-5):(0.1-1):(0.1-2):(5-100).

[0037] The second terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds, preferably water.

[0038] Furthermore, in S10, the reaction temperature of the random polymerization reaction is 0-60° C.; and / or the reaction time of the random polymerization reaction is 100-130 min, preferably 120 min.

[0039] Furthermore, the concentration of the polymerizable monomer is 5-30%, preferably 20%; and / or the amount of the first solvent added relative to the total mass of the polymerizable monomer is 50-50000 mg / kg, preferably 10000 mg / kg; and / or the amount of the first initiator added relative to the total mass of the polymerizable monomer is 100-750 mg / kg, preferably 240 mg / kg; and / or the molar ratio of the first terminator to the first initiator is 0.9-2.0, preferably 2.0; and / or the mass fraction of the mass of the styrene and the third functional monomer to the total mass of the monomers is 5-95%, preferably 30%; wherein the mass ratio of the third functional monomer to the styrene is (1-70):(30-99), preferably (4-7):(93-96).

[0040] Furthermore, the preparation method further comprises: S40, adding an antioxidant to the solution polymerized styrene-butadiene rubber solution obtained in S20; The antioxidant is selected from one or more of 2,6-di-tert-butyl-p-cresol, antioxidant 1076, antioxidant 1520, antioxidant 168, antioxidant 626, hindered phenol, hindered amine, and phosphate compounds, preferably a ternary compound antioxidant system of 1076 / 168 / 626; and / or The antioxidant is added in an amount of 0.01-0.3%wt, preferably 0.6%wt, relative to the in-chain functionalized solution-polymerized styrene-butadiene rubber.

[0041] The present invention also provides a chain-functionalized solution-polymerized styrene-butadiene rubber, which is obtained by the preparation method of any of the above technical solutions. The obtained chain-functionalized solution-polymerized styrene-butadiene rubber has the following characteristics: The vinyl structural unit in the butadiene structural unit of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 6 to 90%, preferably 13 to 60%, and most preferably 40%; The number average molecular weight of the chain functionalized solution-polymerized styrene-butadiene rubber is 100,000 to 1,000,000 g / mol, preferably 400,000 to 500,000 g / mol, and most preferably 470,000 g / mol; The Mooney viscosity of the in-chain functionalized solution-polymerized styrene-butadiene rubber is 30 to 80, preferably 55 to 65, and most preferably 65; The molecular weight distribution of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 1.0 to 2.0, preferably 1.3 to 1.5, and most preferably 1.3; The glass transition temperature of the in-chain functionalized solution-polymerized styrene-butadiene rubber is -50 to 0°C, preferably -20 to -15°C, and most preferably -17°C; The modification rate of the chain-functionalized solution-polymerized styrene-butadiene rubber is greater than 90%, preferably greater than 97%; The nitrogen content of the chain-functionalized solution-polymerized styrene-butadiene rubber is 800-1200 mg / kg, preferably 1100 mg / kg solution-polymerized styrene-butadiene rubber.

[0042] In the following examples, the third monomer and the chain functionalized solution-polymerized styrene-butadiene rubber were characterized, tested and analyzed using the following methods: Molecular structure analysis method: The sample was analyzed using a 600 MHz superconducting Fourier transform nuclear magnetic resonance spectrometer from Brucker, where the 1H spectrum observation frequency was 600 MHz and the 13C spectrum observation frequency was 150.9 MHz. The solvent was CDCl3, TMS was the internal standard, and the test temperature was 20°C.

[0043] Mooney viscosity test: A sample having a weight of 15 g or more was preheated for 1 minute and then measured at 100° C. for 4 minutes using MV-2000 manufactured by ALPHA Technologies.

[0044] Molecular weight (number average molecular weight, weight average molecular weight, polydispersity index): measured by gel permeation chromatography (GPC) at 40°C. Polystyrene monodisperse standard was used as the standard sample for calculating the molecular weight; THF was used as the mobile phase with a flow rate of 1 ml / min.

[0045] Modification rate analysis method: Using the modified styrene butadiene rubber in the chain as a sample, the content of the modified styrene butadiene rubber component in the chain is determined by utilizing the property that the modified styrene butadiene rubber component in the chain will be adsorbed on the GPC column with silica gel as a filler. The amount of adsorption of the modified styrene butadiene rubber component in the chain on the silica column is determined by the difference in the chromatogram (the difference in the chromatogram is the difference between the chromatogram obtained by measuring the sample solution containing the sample and the low molecular weight internal standard polystyrene using a polystyrene gel column and the chromatogram obtained by measuring the sample solution using a silica column). GPC analysis sample preparation method: 10 mg of the sample and 5 mg of the standard low molecular weight polystyrene internal standard are dissolved in 20 ml of tetrahydrofuran. Polystyrene column GPC measurement conditions: THF is used as the eluent, and 200 μL of the sample is injected into the device for measurement. The guard column: the trade name "TSK guard column HHR-H" manufactured by Tosoh Corporation and the three columns: the trade name "TSKgelSuper Multipore HZ-H" manufactured by Tosoh Corporation are connected and used. The chromatogram was obtained by measuring with an RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) at a column box temperature of 40°C and a THF solution flow rate of 1.0 mL / min. Silica column GPC measurement conditions: THF was used as an eluent, and 200 μL of the sample was injected into the device for measurement. Three silica columns with the trade names "Zorbax PSM-1000S", "PSM-300S" and "PSM-60S" were connected and used, and a trade name "DIOL 4.6×12.5mm 5micron" was connected to the front section as a guard column. The chromatogram was obtained by measuring with an RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) at a column box temperature of 40°C and a THF flow rate of 0.5 mL / min. Calculation method of modification rate (content of modified styrene-butadiene rubber in the chain): set the peak area of ​​the chromatogram using a polystyrene column as 100, set the peak area of ​​the sample as P1, and the peak area of ​​the standard polystyrene as P2; set the peak area of ​​the chromatogram using a silica column as 100, set the area of ​​the sample as P3, and the peak area of ​​the standard polystyrene as P4, and calculate the modification rate (%) by the following formula: Modification rate (%) = [1-(P2×P3) / (P1×P4)]×100 (where P1+P2=P3+P4=100) Nuclear magnetic resonance analysis: The microstructure of the sample was analyzed using a 600 MHz superconducting Fourier transform nuclear magnetic resonance spectrometer from Brucker. The 1H spectrum observation frequency was 600 MHz, and the 13C spectrum observation frequency was 150.9 MHz. The solvent was CDCl3, TMS was the internal standard, and the test temperature was 20°C. This method can be used to analyze the styrene content, vinyl content, and grafting rate of thiol compounds in styrene-butadiene rubber.

[0046] DSC thermal performance analysis: 15-20 mg of sample is taken, the temperature test range is -120℃ to 120℃, the thermal history is eliminated before the formal test, the heating and cooling rate is 10℃ / min, and the dwell time of the highest and lowest temperatures is 5min. This method can be used to analyze the glass transition temperature of styrene-butadiene rubber.

[0047] Conversion rate test method: Use a special cylindrical container to take out a small amount of glue from the reactor, then measure the total weight of the cylindrical container containing the polymer solution (A), then transfer the polymer solution in the cylindrical container to an aluminum pan, measure the weight of the cylindrical container after removing the polymer solution (B), dry the aluminum pan containing the polymer solution in a vacuum oven at 100°C for more than 180 minutes until the polymer is completely dry and transparent, finally measure the weight of the dry polymer (C), and calculate the polymer conversion rate according to the following mathematical formula.

[0048] Nitrogen content analysis method: N content is measured by NSX analysis method using a trace nitrogen quantitative analyzer (NSX-2100H). Specifically, the trace nitrogen quantitative analyzer (autosampler, horizontal furnace, PMT & Nitrogen detector) is turned on, the carrier gas flow rate is set to 250ml / min for Ar, 350ml / min for oxygen, 300ml / min for the ozone generator, the heater is set to 800°C, and the analyzer is placed for about 3 hours to stabilize. After stabilizing the analyzer, a calibration curve with a calibration curve range of 5ppm, 10ppm, 50ppm, 100ppm and 500ppm is made using a nitrogen standard (AccuStandard S-22750-01 to 5ml), and the area corresponding to each concentration is obtained. Afterwards, a ceramic boat containing 20mg of sample is placed in the autosampler of the analyzer and measured to obtain the area. The N content is calculated by using the sample area and calibration curve thus obtained.

[0049] Example 1 An embodiment of the present invention provides a method for preparing a third functional monomer. The preparation process of the third functional monomer is carried out under a nitrogen atmosphere with a purity level of 99.99% or higher, and the specific steps are as follows: S11, add 0.5 mol of dimethylamine and 25 ml of 2.0 mol / L n-butyl lithium solution to 25 ml of cyclohexane, and stir the mixture to react for 5 to 60 min at room temperature; S12, add 50 ml of cyclohexane, 0.5 mol of p-divinylbenzene and 0.5 mol of butadiene, and stir and mix them evenly at 0-10°C; S13. Transfer the reaction solution obtained in S11 to a titration funnel and slowly add it dropwise to the solution prepared in S12 within 10 minutes while stirring.

[0050] S14, after the dropwise addition reaction is completed, the reaction solution is gradually heated to room temperature, and after the reaction solution is carefully observed to gradually change from light yellow to golden yellow, 9 ml of deionized water is immediately added and vigorously stirred for 2 min to terminate the activity of the third functional monomer, and the color fades to colorless and transparent to obtain a third functional monomer solution with a concentration of 0.5 mol / L, which can be directly used to prepare in-chain functionalized solution-polymerized styrene-butadiene rubber; S15. Add 50 ml of deionized water to the third functional monomer solution obtained in S14, shake vigorously, and then let it stand in a separatory funnel to separate the layers, remove the lower aqueous phase, and retain the upper oil phase; then add 50 ml of deionized water, and repeat the above operation for more than 3 times until the pH value of the aqueous phase is 6-7 as measured by pH test paper, and the lithium hydroxide in the third monomer solution is completely eluted and removed, and then concentrated by a rotary evaporator to remove 80% of the solvent, and then the concentrated solution is placed in a glass culture dish, and placed in a vacuum oven at 70°C for vacuum drying for 24 hours to obtain a completely dry white or light gray solid powder. The specific reaction mechanism is as follows: Figure 1 shown.

[0051] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 , two Methylamine molecular structure Figure 6 , two Methylamine H NMR spectrum Figure 7 The molecular structure of the third functional monomer (p-(N,N-dimethylaminohexyl)styrene) obtained in Example 1 is shown in Figure 8 , the third functional monomer (p-(N,N-dimethylaminohexyl)styrene) H NMR spectrum is shown in Fig. 9In comparison, the chemical shift of amino hydrogen atoms (i.e., NH) at around 3.3 ppm disappears, and a characteristic peak of o-nitromethyl hydrogen appears at around 2.1-2.5 ppm, proving that the method of Example 1 synthesized a functional monomer modified with p-dimethylamino. The sum of the mass of p-divinylbenzene, butadiene, and dimethylamine is W1, and the mass of the product is W2. The conversion rate is calculated to be 96% according to the following formula.

[0052] The calculation formula is as follows: Example 2 The embodiment of the present invention provides a method for preparing a third functional monomer. The relevant process conditions in Example 1 remain unchanged, and only the dimethylamine in step S11 is replaced by pyrrolidine. The specific reaction mechanism is as follows: Figure 1 shown.

[0053] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 、The molecular structure of pyrrolidine is shown in Fig.10 , pyrrolidine H NMR spectrum see Fig.11 The molecular structure of the third functional monomer obtained in Example 2 is shown in Fig.12 , the third functional monomer H NMR spectrum is shown in Fig.13 In comparison, the chemical shift of the amino hydrogen atom (i.e., NH) disappeared at 2.0 ppm, and the characteristic peak of the o-nitromethylene hydrogen appeared at 3.0 ppm, proving that the method can synthesize the functional monomer modified with para-pyrrolidine with a conversion rate of 97%.

[0054] Example 3 The embodiment of the present invention provides a method for preparing a third functional monomer. The relevant process conditions in Example 1 remain unchanged, and only the dimethylamine in step S11 is replaced by piperidine. The specific reaction mechanism is as follows: Figure 1 shown.

[0055] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 、Piperidine molecular structure Fig.14 , piperidine H NMR spectrum see Fig.15 The molecular structure of the third functional monomer obtained in Example 3 is shown in Fig.16 , the third functional monomer H NMR spectrum is shown in Fig.17In comparison, the chemical shift of the amino hydrogen atom (i.e., NH) disappeared at 2.0 ppm, and the characteristic peak of the o-nitromethylene hydrogen appeared at 3.0 ppm, proving that the method can synthesize a functional monomer modified with a p-piperidinyl group with a conversion rate of 97%.

[0056] Example 4 The embodiment of the present invention provides a method for preparing a third functional monomer. The relevant process conditions in Example 1 remain unchanged, and only the dimethylamine in step S11 is replaced by hexamethyleneimine. The specific reaction mechanism is as follows: Figure 1 shown.

[0057] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 , six The molecular structure of methyleneimine is shown in Fig.18 , six The H NMR spectrum of methyleneimine is shown in Fig.19 The molecular structure of the third functional monomer obtained in Example 4 is shown in Fig. 20 , the third functional monomer H NMR spectrum is shown in Fig.21 In comparison, the chemical shift of the amino hydrogen atom (i.e., NH) at 1.5 ppm disappeared, and the characteristic peak of o-nitrogen methylene hydrogen appeared between 3.0 and 3.1 ppm, proving that this method can synthesize a functional monomer modified with para-hexamethyleneimine with a conversion rate of 98%.

[0058] Example 5 The embodiment of the present invention provides a method for preparing a third functional monomer, wherein the relevant process conditions in Example 1 remain unchanged, and only the dimethylamine in step S11 is replaced by heptamethyleneimine. The specific reaction mechanism is as follows: Figure 1 shown.

[0059] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 , seven The molecular structure of methyleneimine is shown in Fig. 22 , seven The H NMR spectrum of methyleneimine is shown in Fig.23 The molecular structure of the third functional monomer obtained in Example 5 is shown in Fig.24 , the third functional monomer H NMR spectrum is shown in Fig.25In comparison, the chemical shift of the amino hydrogen atom (i.e., NH) at 1.5 ppm disappeared, and the characteristic peak of ortho-nitrogen methylene hydrogen appeared at 3.0 ppm, proving that this method can synthesize a functional monomer modified with a para-heptamethyleneimine group with a conversion rate of 96%.

[0060] Example 6 The embodiment of the present invention provides a method for preparing a third functional monomer. The relevant process conditions in Example 1 remain unchanged, and only the dimethylamine in step S11 is replaced by dodecamethyleneimine. The specific reaction mechanism is as follows: Figure 1 shown.

[0061] According to the molecular structure of butadiene Figure 2 , butadiene NMR hydrogen spectrum see 3, p-divinylbenzene molecular structure see Figure 4 , p-divinylbenzene H NMR spectrum see Figure 5 , twelve The molecular structure of methyleneimine is shown in Fig.26 , twelve The H NMR spectrum of methyleneimine is shown in Fig. 27 The molecular structure of the third functional monomer obtained in Example 6 is shown in Fig.28 , the third functional monomer H NMR spectrum is shown in Fig.29 In comparison, the chemical shift of the amino hydrogen atom (i.e., NH) at 1.5 ppm disappeared, and the characteristic peak of ortho-nitrogen methylene hydrogen appeared at 3.0 ppm, proving that the method can synthesize a functional monomer modified with para-dodecanedimino group with a conversion rate of 96%.

[0062] Example 7 The embodiment of the present invention provides a method for preparing a third functional monomer, wherein the relevant process conditions in Example 4 remain unchanged, and only step S12 is replaced by adding 50 ml of cyclohexane and 0.5 mol of p-divinylbenzene or 0.5 mol of p-diisopropenylbenzene, and stirring and mixing at 0-10° C. The specific reaction mechanism is as follows Fig.30 shown.

[0063] Example 8 The embodiment of the present invention provides a method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber. The anionic polymerization process of the chain-functionalized solution-polymerized styrene-butadiene rubber is carried out under a nitrogen atmosphere with a purity level of 99.99% or more, and the specific steps are as follows: S10. Using cyclohexane as solvent, tetrahydrofuran as activator and n-butyl lithium as initiator, random copolymerization of butadiene, styrene and the third functional monomer was initiated at 0-60°C for 120 min to obtain an active molecular chain of chain-functionalized solution-polymerized styrene-butadiene rubber. The maximum temperature during the reaction reached 90-100°C.

[0064] S20, adding terminator water to the active molecular chain of the chain-functionalized solution-polymerized styrene-butadiene rubber, rapidly stirring for 5 to 15 minutes to terminate the polymerization reaction, and obtaining a chain-functionalized solution-polymerized styrene-butadiene rubber solution.

[0065] S30, add alcohol to the chain functionalized solution polymerized styrene butadiene rubber solution to precipitate the styrene butadiene rubber, pour off the upper solvent, put the milky white chain functionalized solution polymerized styrene butadiene rubber wet block into a stainless steel tray, and then put it into a 70°C vacuum oven for vacuum drying for 24 hours, and finally obtain colorless and transparent chain functionalized solution polymerized styrene butadiene rubber. The specific reaction mechanism is as follows Fig.31 shown.

[0066] In the preparation process, the added amount of 2 mol / L n-butyl lithium initiator is 2.1 mL; the added amount of tetrahydrofuran is 10000 mg / kg styrene-butadiene rubber; the mass ratio of styrene monomer to butadiene monomer is 30 / 70; the total weight of monomers is 1000 g; the added amount of solvent is 4000 g; the concentration of polymerized monomers is 20%; the added amount of the third functional monomer accounts for 6% of the mass fraction of the vinyl aromatic monomer; and the molar ratio of the terminator water to n-butyl lithium is 2:1.

[0067] Example 9 The embodiment of the present invention provides a method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 8 remain unchanged, and only S40 is included after S20 and before S30, wherein S40, a ternary compounded antioxidant system of 1076 / 168 / 626 is added to the chain-functionalized solution-polymerized styrene-butadiene rubber solution obtained in S20. In S40, the amount of the antioxidant added relative to the chain-functionalized solution-polymerized styrene-butadiene rubber is 0.05%wt.

[0068] Example 10 The embodiment of the present invention provides a method for preparing in-chain functionalized solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 9 remain unchanged, except that the third functional monomer in step S10 is the third functional monomer obtained in Example 2 (p-(6-pyrrolidinylhexyl)styrene).

[0069] Embodiment 11 The embodiment of the present invention provides a method for preparing in-chain functionalized solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 9 remain unchanged, except that the third functional monomer in step S10 is the third functional monomer obtained in Example 4 (p-(6-hexamethyleneiminohexyl)styrene).

[0070] Example 12 An embodiment of the present invention provides a method for preparing in-chain functionalized solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 9 remain unchanged, except that the third functional monomer in step S10 is the third functional monomer obtained in Example 1 (p-(N,N-dimethylaminohexyl)styrene).

[0071] Embodiment 13 The embodiment of the present invention provides a method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 9 remain unchanged, except that the third functional monomer in step S10 is the third functional monomer obtained in Example 7 (p-(6-hexamethyleneiminoethyl)styrene).

[0072] Comparative Example 1 The comparative example of the present invention provides a method for preparing solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in Example 9 remain unchanged, except that the third functional monomer is not added in step S10.

[0073] Comparative Example 2 The comparative example of the present invention provides a method for preparing a solution-polymerized styrene-butadiene rubber. The preparation steps of comparative example 2 are as follows: In the first step, cyclohexane is used as solvent, tetrahydrofuran is used as active agent, and n-butyl lithium is used as initiator to initiate random copolymerization of butadiene and styrene at 0-60°C for 120 minutes to obtain active molecular chains of styrene-butadiene rubber. The maximum temperature during the reaction reaches 90-100°C.

[0074] In the second step, a modifier 3-chloropropyltrimethoxysilane is added to the active molecular chain of styrene-butadiene rubber, and the polymerization reaction is carried out by rapid stirring for 5 to 15 minutes to obtain a modified active molecular chain of styrene-butadiene rubber.

[0075] The third step is to add terminator water to the active molecular chain of the modified styrene butadiene rubber to terminate the polymerization, and then add the antioxidant 1076 / 168 / 626 ternary compound antioxidant system to obtain a modified functionalized solution-polymerized styrene butadiene rubber solution.

[0076] The fourth step is to add alcohol to the modified functionalized solution polymerized styrene butadiene rubber solution to precipitate the modified functionalized solution polymerized styrene butadiene rubber, pour out the upper solvent, put the wet rubber block of the milky white chain functionalized solution polymerized styrene butadiene rubber into a stainless steel tray, and then put it into a vacuum oven at 70°C for vacuum drying for 24 hours, and finally obtain colorless and transparent modified functionalized solution polymerized styrene butadiene rubber.

[0077] In the preparation process, the addition amount of 2 mol / L n-butyl lithium initiator is 2.1 mL; the addition amount of tetrahydrofuran is 10000 mg / kg styrene-butadiene rubber; the mass ratio of styrene monomer to butadiene monomer is 30 / 70; the total weight of monomers is 1000 g; the addition amount of solvent is 4000 g; the monomer concentration is 20%; the molar ratio of terminator water to n-butyl lithium is 2:1; the addition amount of antioxidant to chain functionalized solution-polymerized styrene-butadiene rubber is 0.05% wt; and the molar ratio of modifier to n-butyl lithium is 1.2:1.

[0078] Comparative Example 3 The comparative example of the present invention provides a method for preparing a solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in comparative example 2 remain unchanged, and only the modifier (3-chloropropyltrimethoxysilane) in the second step is replaced by a modifier (N,N-dimethylaminopropyltrimethoxysilane).

[0079] Comparative Example 4 The comparative example of the present invention provides a method for preparing a solution-polymerized styrene-butadiene rubber, wherein the relevant process conditions in comparative example 2 remain unchanged, and only the modifier (3-chloropropyltrimethoxysilane) in the second step is replaced by a modifier (4-vinyl-N,N-dimethylbenzylamine).

[0080] Through the data analysis and comparison in Table 1, the differences between the mid-chain modification technology and the chain-end modification technology of SSBR (solution styrene butadiene rubber) are as follows: (1) The modification rate of the mid-chain modified SSBR is higher, which shows that the mid-chain modification technology of the present invention has higher reaction activity.

[0081] (2) The nitrogen content of the mid-chain modified SSBR is higher. It can be seen that the mid-chain modification technology can give SSBR a higher degree of functionalization, thereby significantly improving the interfacial bonding strength between SSBR and silica.

[0082] (3) The molecular weight and Mooney viscosity of the mid-chain modified SSBR are higher. It can be seen that the interaction force between the molecular chains of the mid-chain modified SSBR is significantly higher than that of the chain end modification technology.

[0083] Table 1 shows the characterization analysis results of the embodiments and comparative examples. In order to evaluate the application performance of the chain-functionalized solution-polymerized styrene-butadiene rubber after being made into vulcanized rubber, the present invention also prepares vulcanized rubber by using the chain-functionalized solution-polymerized styrene-butadiene rubber obtained in Examples 10 to 13 and the chain-end functionalized solution-polymerized styrene-butadiene rubber modified with primary amino groups obtained in Comparative Examples 1 to 4.

[0084] The vulcanized rubber was prepared by first-stage mixing and second-stage mixing. In the first-stage mixing, rubber, silica, organic silane coupling agent (X50S, Evonik), process oil (TDAE), zinc oxide (zinc white), stearic acid, antioxidant (TMQ(RD)) (2,2,4-trimethyl-1,2-dihydroquinoline polymer), anti-aging agent (6PPD (dimethylbutyl-N-phenyl-phenylenediamine) and microcrystalline wax) were mixed using a Banbury mixer equipped with a temperature control device. In this case, the initial temperature of the mixing device was controlled at 70°C, and after the mixing was completed, the first mixed rubber was obtained at a discharge temperature of 145°C. In the second stage of mixing, the first rubber mix was cooled to room temperature, and the first rubber mix, sulfur, rubber accelerator (DPD (diphenylguanidine)) and vulcanization accelerator (CZ (N-cyclohexyl-2-benzothiazolylsulfenamide)) were added to the mixer and mixed at a temperature below 100°C to obtain the second rubber mix. Finally, the vulcanized rubber sample was prepared by vulcanization crosslinking in a flat vulcanizer at 160°C for 20 minutes.

[0085] Table 2 is the mixing formula of vulcanized rubber Note: The raw material amounts in Table 2 are expressed in parts by weight based on 100 parts by weight of styrene-butadiene rubber.

[0086] The test methods for the physical properties of vulcanized rubber are as follows: Vulcanized rubber tensile test: The tensile strength when the test sample is cut and the tensile stress at 300% elongation (300% tensile strength) are measured according to the tensile test method of ASTM 412. For this purpose, a Universal Test Machine 4204 manufactured by Instron is used, and the tensile strength, modulus and elongation are measured at room temperature at a tensile rate of 50 cm / min.

[0087] Vulcanized rubber dynamic mechanical properties test: A dynamic mechanical analyzer manufactured by TA was used. The loss factor Tanδ of each sample was measured when deformed under the conditions of a 10Hz frequency of the deformation mode and a measurement temperature ranging from -60°C to 80°C. The Payne effect is represented by the difference between the minimum and maximum values ​​in the deformation range of 0.28% to 40%. The lower the Payne effect, the higher the filler dispersion. When the loss factor at 0°C increases, the anti-skid property is better, and when the loss factor at 60°C decreases, the hysteresis loss decreases and the rolling resistance decreases, that is, the fuel economy is increased. When the loss modulus at 60°C decreases, the internal heat generation of the rubber decreases, the hysteresis loss decreases, and the dynamic performance improves.

[0088] DIN abrasion resistance test of vulcanized rubber: For each vulcanized rubber sample, a DIN abrasion test was performed based on ASTM D5963 and displayed by the DIN loss index (volume index: ARIA (Abrasion Resistance Index, Method A)).

[0089] Table 3 shows the physical properties of the vulcanized rubber samples prepared from the SSBR in Examples 10 to 13 and Comparative Examples 1 to 4. From the comparison of the Mooney viscosity of the mixed rubber, the Mooney viscosity of all the mixed rubbers has increased compared with the raw rubber, but the Mooney viscosity of the mixed rubbers of Examples 10 to 13 has not increased significantly compared with the raw rubber, and is much lower than that of Comparative Examples 1 to 4. It can be seen that compared with the chain end modification technology, the SSBR modified in the chain has the best mixing and dispersion performance with the rubber filler, is easy to eat, and the heat generated during the mixing process is not high, so the pre-vulcanization degree of its mixed rubber is the lowest. The data characteristics reflected are: the Mooney viscosity of the mixed rubber is not significantly increased compared with the Mooney of the raw rubber. Compared with Comparative Example 1, the Mooney of the mixed rubber of Comparative Examples 2 to 4 is lower, but significantly higher than that of Examples 10 to 13.

[0090] The 300% tensile strength and elongation at break of the embodiments and comparative examples are not much different, but the tensile strength of embodiments 10 to 13 is significantly higher than that of comparative examples 1 to 4. Among them, although the tensile strength of comparative examples 2 to 4 is slightly higher than that of comparative example 1, it is significantly lower than that of embodiments 10 to 13. It shows that compared with the chain end modification technology, the mixing and dispersion performance of the mid-chain modified SSBR and the rubber filler is the best, the filler-polymer network of the prepared vulcanized rubber is the most complete, the mechanical properties are the best, and the mid-chain modification technology is more advantageous.

[0091] The higher the wear resistance index, the better the wear resistance of the vulcanized rubber. The wear resistance index of Examples 10 to 13 is significantly higher than that of Comparative Examples 1 to 4, indicating that the chain modification technology improves the wear resistance of SSBR. Moreover, the excellent wear resistance of Examples 10 to 13 can also be reflected from their high molecular weight.

[0092] The higher the 0℃ loss factor, the higher the anti-slip and grip of the vulcanized rubber. The 0℃ loss factors of Examples 10 to 13 are all greater than 0.3, which are higher than Comparative Examples 10 to 13, so the mid-chain modification technology gives SSBR excellent grip and anti-slip properties on ice. Comparative Examples 2 to 4 are not much different from the examples, and are all higher than Comparative Example 1, indicating that the chain end modification technology can also improve the grip performance of SSBR, but it is much worse than the mid-chain modification technology.

[0093] The lower the 60°C loss factor, the lower the rolling resistance of the vulcanized rubber, and the use of tires can improve the fuel economy of automobiles. The 60°C loss factors of Examples 10 to 13 are all lower than 0.1000, slightly lower than Comparative Example 1, and not much different from Comparative Examples 2 to 4. This shows that the chain modification technology mainly improves the 0°C loss factor, but has little effect on the 60°C loss factor, indicating that the chain modification technology significantly reduces the hysteresis loss of SSBR and has excellent dynamic performance.

[0094] The lower the 60°C loss modulus, the lower the endogenous heat of the vulcanized rubber, the better the dynamic performance, and the better the fatigue resistance when used as a tire. The 60°C loss modulus of Examples 10 to 13 is lower than that of Comparative Examples 1 to 4, indicating that the endogenous heat of the chain-modified SSBR is lower and the fatigue resistance is better. Similarly, the 60°C loss modulus of Comparative Examples 2 to 4 is lower than that of Comparative Example 1, indicating that the chain end modification technology of tertiary amine groups and siloxane groups can also improve the dynamic performance and fatigue resistance of SSBR, but the improvement effect is slightly lower than that of the chain modification technology.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a chain-functionalized solution-polymerized styrene-butadiene rubber, characterized in that: The preparation method comprises the following steps: S10, in a polymerization system, using alkanes as the first solvent, ethers as the activator, butadiene, styrene, and the third functional monomer as the polymerization monomers, and organic lithium as the first initiator, to perform a random polymerization reaction to obtain an active butadiene-styrene rubber solution; S20, adding a first terminator to the active styrene-butadiene rubber solution to terminate the random polymerization reaction to obtain a solution-polymerized styrene-butadiene rubber solution; S30, the solution polymerized styrene butadiene rubber solution is precipitated and dried to obtain the in-chain functionalized solution polymerized styrene butadiene rubber; The third functional monomer is a functional monomer containing an amino functional group obtained by polymerizing a secondary amine monomer with an olefin monomer using alkanes as the second solvent and organic lithium as the second initiator; the olefin monomer is a divinyl aromatic monomer and / or a conjugated diene monomer.

2. The preparation method according to claim 1, characterized in that: The secondary amine monomer is selected from one or more of dimethylamine, pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine and dodecamethyleneimine; and / or The divinyl aromatic monomer is selected from one or more of o- / m- / p-divinylbenzene and o- / m- / p-diisopropenylbenzene; and / or The conjugated diene monomer is selected from one or more of butadiene, isoprene, styrene and piperylene.

3. The preparation method according to claim 1, characterized in that: The alkanes are selected from one or more of cyclopentane, cyclohexane, heptane and octane; and / or The ethers are selected from one or more of tetrahydrofuran, tetrahydrofurfuryl ether, diethylene glycol dimethyl ether, ethyl ether, ethyl methyl ether, anisole, and diphenyl ether; and / or The organic lithium is selected from one or more of alkyl lithium, aryl lithium, arylalkyl lithium and cycloalkyl lithium; and / or The first terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds.

4. The preparation method according to claim 1, characterized in that: The preparation method of the third functional monomer comprises the following steps: S11, adding the second initiator and the secondary amine monomer to the second solvent, stirring and mixing, the reaction time is 5 to 60 minutes, to obtain an amide-containing lithium compound solution; S12, adding the olefinic monomer to the second solvent, stirring and mixing at a temperature of 0 to 10° C. to obtain a homogeneous olefinic monomer solution; S13, adding the amide-containing lithium compound solution to the olefinic monomer homogeneous solution, stirring and mixing, to obtain an active third functional monomer solution; S14, adding the second terminator to the active third functional monomer solution to terminate the reaction and obtain a third functional monomer solution. S15, washing and drying the third functional monomer solution to obtain the third functional monomer.

5. The preparation method according to claim 4, characterized in that: The molar ratio of the secondary amine monomer, the conjugated diene monomer, the divinyl aromatic monomer, the second initiator, the second terminator and the second solvent is 1:(0-100):(1-5):(0.1-1):(0.1-2):(5-100); and / or The second terminator is selected from one or more of water, alcohols, acids, phenols, and halogenated hydrocarbon compounds.

6. The preparation method according to claim 1, characterized in that: In said S10, The reaction temperature of the random polymerization reaction is 0-60° C.; and / or The reaction time of the random polymerization reaction is 100-130 min.

7. The preparation method according to claim 1, characterized in that: The concentration of the polymerizable monomer is 5-30%; and / or The amount of the first solvent added relative to the total mass of the polymerizable monomers is 50-50000 mg / kg; and / or The amount of the first initiator added relative to the total mass of the polymerization monomer is 100-750 mg / kg; and / or The molar ratio of the first terminator to the first initiator is 0.9 to 2.0; and / or The mass fraction of the styrene and the third functional monomer to the total mass fraction of the polymerized monomers is 5-95%; wherein the mass ratio of the third functional monomer to the styrene is (1-70): (30-99).

8. The preparation method according to claim 1, characterized in that: The preparation method further comprises: S40, adding an antioxidant to the solution polymerized styrene-butadiene rubber solution obtained in S20; Wherein, the antioxidant is selected from one or more of 2,6-di-tert-butyl-p-cresol, antioxidant 1076, antioxidant 1520, antioxidant 168, antioxidant 626, hindered phenol, hindered amine, and phosphate compound; and / or The antioxidant is added in an amount of 0.01-0.3%wt relative to the solution-polymerized styrene-butadiene rubber.

9. A chain-functionalized solution-polymerized styrene-butadiene rubber, characterized in that: The in-chain functionalized solution-polymerized styrene-butadiene rubber is prepared by the preparation method described in any one of claims 1-8.

10. The in-chain functionalized solution-polymerized styrene-butadiene rubber according to claim 9, characterized in that: The vinyl structural unit in the butadiene structural unit of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 6 to 90%; The number average molecular weight of the chain functionalized solution-polymerized styrene-butadiene rubber is 100,000 to 1,000,000 g / mol; The Mooney viscosity of the chain-functionalized solution-polymerized styrene-butadiene rubber is 30 to 80; The molecular weight distribution of the functionalized solution-polymerized styrene-butadiene rubber in the chain is 1.0-2.0; The glass transition temperature of the in-chain functionalized solution-polymerized styrene-butadiene rubber is -50 to 0°C; The modification rate of the functionalized solution-polymerized styrene-butadiene rubber in the chain is greater than 90%; The nitrogen content of the chain-functionalized solution-polymerized styrene-butadiene rubber is 800-1200 mg / kg.

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