Multi-site synergistically functionalized solution styrene-butadiene rubber, its preparation method and application

Abstract

The application discloses a multi-site synergistically functionalized solution polymerized styrene-butadiene rubber (SSBR) and a preparation method and application thereof, and is a double-end capped and side group grafted multi-functionality SSBR. The molecular chain structure of the SSBR is mainly linear and slightly branched. Through accurate regulation and control of the main chain composition, the microstructure and the functional group distribution, the unification of low dynamic heat generation, high mechanical strength, excellent wear resistance and cutting resistance and wide temperature range stability is realized, and the extreme service requirements of special engineering tires and aerospace tires are met.

Description

Technical Field

[0001] This invention relates to the field of rubber synthesis technology, specifically to multi-site synergistic functionalized solution styrene-butadiene rubber (SSBR) and its preparation methods and applications. It is particularly designed for the extreme working conditions of special engineering tires (heavy-duty mining tires, off-road engineering tires) and aerospace tires (civilian passenger aircraft tires, military aircraft tires), achieving comprehensive performance of high wear resistance, low heat generation, high and low temperature resistance, and cut resistance through precise molecular structure design. Background Technology

[0002] Specialty engineering tires and aircraft tires have much higher performance requirements for the rubber matrix than ordinary passenger tires: Engineering tires: They need to withstand high loads, strong impacts, and wear from rough road surfaces, requiring the rubber to have ultra-high tensile strength, excellent wear resistance, and resistance to cutting and punctures. Aviation tires: During takeoff and landing, the linear speed exceeds 300 km / h, generating extremely high instantaneous heat. They must also withstand high-altitude low temperatures of -55℃ and landing high temperatures of over 120℃, requiring extremely low dynamic heat generation, wide temperature range elastic stability, and fatigue resistance.

[0003] Existing commercial SSBRs are mostly single-end functionalized or random copolymer structures, which have three major drawbacks: The functional groups are only distributed at one end of the molecular chain, resulting in insufficient interfacial bonding with silica / carbon black fillers. The filler network is prone to agglomeration, and the dynamic heat generation is high, which cannot meet the high-speed and low-heat generation requirements of aviation tires. The side chain has no functional groups and the functional group density is low, so the improvement of the wear resistance and cut resistance of the vulcanizate is limited, making it difficult to adapt to the heavy wear conditions of engineering tires. The precision of styrene sequence and butadiene vinyl structure regulation is insufficient, the glass transition temperature (Tg) range is narrow, and it is difficult to balance high and low temperature performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a solution-polymerized styrene-butadiene rubber (SSBR) with multi-site synergistic functionalization at the "initiator-side group-terminator" stage. By precisely controlling the main chain composition, microstructure, and functional group distribution, it achieves a balance of low dynamic heat generation, high mechanical strength, excellent wear and cut resistance, and wide temperature range stability, thus meeting the extreme service requirements of special engineering tires and aerospace tires.

[0005] The technical solution of this invention is as follows: A multi-site synergistic functionalized solution-polymerized styrene-butadiene rubber is a multifunctional SSBR with double-end capping and side-group grafting. The SSBR molecular chain structure is mainly linear with slight branching. Main chain composition: 25%-40% by weight of polystyrene units, 58%-74% by weight of polybutadiene units, and 1%-3% by weight of side-functionalized comonomers; the molar proportion of vinyl structures formed by 1,2 polymerization in polybutadiene units is 35%-55%, and polystyrene units and polybutadiene units are mainly randomly distributed in the molecular chain, with a small amount of block polystyrene at the chain ends to improve the high-temperature modulus; Functional group distribution: Initiation end: amino / hydroxyalkyl polar functional groups, which can form hydrogen bonds with hydroxyl groups on the filler surface; Termination end: Trialkoxysilyl / epoxypropoxy reactive functional group, which can chemically bond with silica; Side groups: siloxane functional groups are grafted onto the side of the main chain, with an average functional group density of 0.5-2.0 groups per molecular chain, which strengthens the interfacial bonding of the filler. Molecular weight and distribution: Number average molecular weight (Mn) is (180,000-320,000), and molecular weight distribution index (PDI) is (1.3-1.8). After multifunctional group coupling, the branched / coupling component accounts for 10%-25% of the weight, balancing mechanical properties and processing flowability.

[0006] The initiation-end functional groups are introduced through functionalized organolithium initiators, all of which are tertiary amino or protected hydroxyalkyl structures that do not interfere with the anionic polymerization activity. They can form hydrogen bonds with the hydroxyl groups on the filler surface. Specific optional systems are as follows: The amino-based polar functional group (corresponding to tertiary amino-functionalized alkyl lithium initiators) can be: Dimethylaminopropyl (corresponding initiator: 3-dimethylaminopropyllithium): CAS No. 56633-21-7, molecular formula C5H12LiN, structural formula (CH3)2NCH2CH2CH2Li; Diethylaminopropyl (corresponding initiator: 3-diethylaminopropyllithium): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C7H16LiN, structural formula (C2H5)2NCH2CH2CH2Li; Pyrrolidinylpropyl (corresponding initiator: 1-(3-lithiumpropyl)pyrrolidinane): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C7H14LiN, structural formula C4H8NCH2CH2CH2Li; Piperidinylpropyl (corresponding initiator: 1-(3-lithiumpropyl)piperidine): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C8H16LiN, structural formula C5H10NCH2CH2CH2Li; Morpholinylpropyl (corresponding initiator: 4-(3-lithiumpropyl)morpholine): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C7H14LiNO, structural formula OC4H8NCH2CH2CH2Li; The preferred amino polar functional group is the hexamethyleneiminopropyl group in lithium hexamethyleneiminopropyl (HMI-Li). Its chemical structure is as follows: the nitrogen atom of the six-membered ring hexamethyleneimine (cyclohexylimine, (CH2)6NH) is attached to one end of the n-propyl group, and the other end of the propyl group is attached to a lithium atom. The structural formula is (CH2)6N-CH2CH2CH2Li, and the molecular formula is C9H18LiN. The propyl group acts as an alkyl bridge connecting the polar functional group to the active lithium initiation site, ensuring both initiation activity and functional group stability.

[0007] Hydroxyl alkyl polar functional groups (corresponding to protected hydroxyalkyl lithium initiators, which release free hydroxyl groups after deprotection following polymerization) can be: Hydroxyethyl (corresponding initiator: tert-butoxyethyl lithium, acid deprotection): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C6H13LiO, structural formula (CH3)3COCH2CH2Li, and the functional group after deprotection is HOCH2CH2-. Hydroxypropyl (corresponding initiator: tert-butoxypropyl lithium, acid deprotection): Custom initiator for anionic polymerization, no general commercial CAS registration number, molecular formula C7H15LiO, structural formula (CH3)3COCH2CH2CH2Li, functional group after deprotection is HOCH2CH2CH2-. Hydroxybutyl (corresponding initiator: isobutoxybutyllithium, hydroprotected): a custom initiator for anionic polymerization, without a general commercial CAS registration number, molecular formula C8H17LiO, structural formula (CH3)2CHOCH2CH2CH2CH2Li, and the functional group after deprotection is HOCH2CH2CH2CH2-.

[0008] The terminal functional group is introduced through the reaction of the active chain end with a functionalized terminator, and can covalently bond with the hydroxyl groups on the surface of silica. Specific optional systems are as follows: Trialkoxysilyl functional groups (corresponding to silane terminators) can be: Trimethoxysilyl (corresponding terminator: tetramethoxysilane): CAS No. 681-84-5, molecular formula C4H12O4Si, structural formula Si(OCH3)4. Trimethoxysilylpropyl (corresponding terminator: γ-chloropropyltrimethoxysilane): CAS No. 2530-87-2, molecular formula C6H15ClO3Si, structural formula ClCH2CH2CH2Si(OCH3)3; Triethoxysilyl (corresponding terminator: tetraethoxysilane): CAS No. 78-10-4, molecular formula C8H20O4Si, structural formula Si(OC2H5)4; Triethoxysilylpropyl (corresponding terminator: γ-chloropropyltriethoxysilane): CAS No. 5089-70-3, molecular formula C9H21ClO3Si, structural formula ClCH2CH2CH2Si(OC2H5)3; Methyldimethoxysilyl (corresponding terminator: methyltrimethoxysilane): CAS No. 1185-55-3, molecular formula C4H12O3Si, structural formula CH3Si(OCH3)3; Epoxypropoxy reactive functional groups (corresponding to epoxy silane terminators, possessing dual reactive activity of epoxy and alkoxy silane groups). Glycidoxypropyltrimethoxysilyl (corresponding terminator: γ-glycidoxypropyltrimethoxysilane, KH-560): CAS No. 2530-83-8, molecular formula C9H20O5Si, structural formula CH2(O)CHCH2OCH2CH2CH2Si(OCH3)3. Glycidoxypropyltriethoxysilyl (corresponding terminator: γ-glycidoxypropyltriethoxysilane, KH-561): CAS No. 2602-34-8, molecular formula C12H26O5Si, structural formula CH2(O)CHCH2OCH2CH2CH2Si(OC2H5)3; Epoxycyclohexylethyltrimethoxysilyl (corresponding terminator: β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, KH-566): CAS No. 3388-04-3, molecular formula C11H22O4Si, structural formula C6H9(O)CH2CH2Si(OCH3)3; The preferred reactive functional group at the termination end is propylene oxide propyltrimethoxysilyl, and the corresponding terminator is γ-glycidoxypropyltrimethoxysilane (KH560).

[0009] The side-chain siloxane functional groups are incorporated into the main chain via copolymerization with silane monomers containing polymerizable double bonds. This does not terminate the anionic active chain and can increase the overall functional group density of the molecular chain. Specific comonomers that can be selected are as follows: Vinyltriethoxysilane (VTES): CAS No. 78-08-0, molecular formula C8H18O3Si, structural formula CH2=CHSi(OC2H5)3; Vinyltrimethoxysilane (VTMS): CAS No. 2768-02-7, molecular formula C5H12O3Si, structural formula CH2=CHSi(OCH3)3; Vinyltriisopropoxysilane: CAS No. 18023-33-1, molecular formula C11H24O3Si, structural formula CH2=CHSi(OCH(CH3)2)3; Allyltrimethoxysilane: CAS No. 2551-83-9, molecular formula C6H14O3Si, structural formula CH2=CHCH2Si(OCH3)3; Styrenetrimethoxysilane: CAS No. 18001-13-3, molecular formula C11H16O3Si, structural formula CH2=CHC6H4Si(OCH3)3; γ-Methacryloxypropyltrimethoxysilane (KH-570): CAS No. 2530-85-0, molecular formula C10H20O5Si, structural formula CH2=C(CH3)COOCH2CH2CH2Si(OCH3)3; The preferred method is to graft siloxane functional groups onto the main chain side, specifically vinyltriethoxysilane (VTES) onto the main chain side. Multifunctional coupling involves adding tin tetrachloride as a coupling agent and reacting for 20-30 minutes, with the degree of coupling controlled at 10-25%. The presence of a small amount of block polystyrene at the chain ends refers to the presence of a small amount of block polystyrene at the initiation or termination ends, with a number average molecular weight of 2000-10000.

[0010] Thermal properties: Glass transition temperature (Tg) -58℃ to -42℃, maintains high elasticity at -40℃, and retains ≥80% of the constant elongation stress at 100℃.

[0011] A method for preparing multi-site synergistic functionalized solution polymerized styrene-butadiene rubber. An anionic solution polymerization method was employed, using a cyclohexane-n-hexane mixed solvent as the reaction medium. Precise structural control was achieved through five steps: functionalization initiation, stepwise copolymerization, side-group grafting, functionalization termination, and coupling. The specific process is as follows: Raw material refining: Styrene, butadiene monomers and mixed solvents are refined by molecular sieve and activated alumina in series, with water content controlled to ≤5ppm and polymerization inhibitor content to ≤1ppm; Initiation system: An amino-functionalized organolithium initiator (preferably hexamethyleneimine propyllithium, HMI-Li) or a hydroxyalkyl polar functionalized organolithium initiator is used at a concentration of 0.5-1.5 mol / L, with an initiation efficiency ≥95%; Copolymerization reaction: Solvent, mixed monomers, and polarity modifier (diethylene glycol dimethyl ether) are added to a high-pressure reactor. The temperature is raised to 50-65℃, and then the initiator is added. The reaction is carried out for 30-60 minutes. When the monomer conversion rate reaches 85% or more, vinyltriethoxysilane (VTES) is added as a side-group functionalized monomer, and the reaction is continued for 20-40 minutes until the total conversion rate is ≥99%. Functionalization termination and coupling: First, add epoxypropoxypropyltrimethoxysilane (KH560) for end-group capping reaction for 15-30 min, then add tin tetrachloride (SnCl4) as coupling agent for reaction for 20-30 min, with the coupling degree controlled at 10-25%; Post-processing: High-temperature resistant antioxidant is added, and the product is dehydrated by steam condensation, twin-screw extrusion, and vacuum drying to obtain the finished adhesive.

[0012] Application of the prepared multi-site functionalized solution-polymerized styrene-butadiene rubber in special engineering tires, aerospace tire tread and sidewall rubber.

[0013] Beneficial technical effects Significantly low heat generation performance: Multi-site functional groups form a dual interface bond of "hydrogen bond + covalent bond" with the filler, reducing the Payne effect of the filler network by 40% and the tanδ of the vulcanized rubber at 60℃ by 20-30%, resulting in a significant reduction in dynamic heat generation, which meets the low heat generation requirements for high-speed landing of aircraft tires and heavy-load continuous operation of engineering tires.

[0014] Excellent wear resistance and mechanical properties: Precise control of vinyl and styrene structure combined with uniform dispersion of fillers results in a vulcanizate tensile strength ≥25MPa, Akron abrasion loss reduced by more than 25%, and improved cut and puncture resistance by 30%, making it suitable for complex and harsh road conditions in mining engineering.

[0015] Stable performance over a wide temperature range: wide Tg range, elongation retention rate ≥70% at -40℃ low temperature, and 300% constant elongation stress retention rate ≥80% at 100℃ high temperature, adapting to the extreme temperature environment of high altitude low temperature and high temperature at landing moment for aircraft tires.

[0016] Strong processing adaptability: Narrow molecular weight distribution combined with a slightly branched structure, Mooney viscosity (ML1+4, 100℃) is controlled at 45-65, and the filler dispersion speed is fast during mixing, making it suitable for the molding and vulcanization process of thick products such as large engineering tires and aviation tires. Detailed Implementation To facilitate understanding of the present invention, a more comprehensive description is provided below, outlining preferred embodiments. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the invention more thorough and complete.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for descriptive purposes only and is not intended to limit the invention.

[0018] In the embodiments of the present invention, multi-site synergistic functionalized SSBR is prepared according to the steps in the method for preparing multi-site synergistic functionalized solution polymerized styrene-butadiene rubber.

[0019] An anionic solution polymerization method was employed, using a cyclohexane-n-hexane mixed solvent as the reaction medium. Precise structural control was achieved through five steps: functionalization initiation, stepwise copolymerization, side-group grafting, functionalization termination, and coupling. The specific process is as follows: Raw material refining: Styrene, butadiene monomers and mixed solvents are refined by molecular sieve and activated alumina in series, with water content controlled to ≤5ppm and polymerization inhibitor content to ≤1ppm; Initiation system: An amino-functionalized organolithium initiator (preferably hexamethyleneimine propyllithium, HMI-Li) is used at a concentration of 0.5-1.5 mol / L, with an initiation efficiency ≥95%; Copolymerization reaction: Solvent, mixed monomers, and polarity modifier (diethylene glycol dimethyl ether) are added to a high-pressure reactor. The temperature is raised to 50-65℃, and then the initiator is added. The reaction is carried out for 30-60 minutes. When the monomer conversion rate reaches 85% or more, vinyltriethoxysilane (VTES) is added as a side-group functionalized monomer, and the reaction is continued for 20-40 minutes until the total conversion rate is ≥99%. Functionalization termination and coupling: First, add epoxypropoxypropyltrimethoxysilane (KH560) for end-group capping reaction for 15-30 min, then add tin tetrachloride (SnCl4) as coupling agent for reaction for 20-30 min, with the coupling degree controlled at 10-25%; Post-processing: High-temperature resistant antioxidant is added, and the product is dehydrated by steam condensation, twin-screw extrusion, and vacuum drying to obtain the finished adhesive.

[0020] Example 1 Formula: Styrene 30wt%, Butadiene 68.5wt%, VTES 1.5wt%; Vinyl content 45mol% Process: Anionic polymerization at 60℃, initiated by HMI-Li, terminated by KH560, and coupled with SnCl4; Product parameters: Mn=250,000, PDI=1.5, coupling degree 20%, Tg=-50℃. Example 1

[0021] Formula: Styrene 35wt%, Butadiene 63wt%, VTES 2wt%; Vinyl content 50mol% Process: Anionic polymerization at 65℃, initiated by HMI-Li, terminated by KH560, and coupled with SnCl4; Product parameters: Mn=220,000, PDI=1.6, coupling degree 22%, Tg=-45℃. Example 2

[0022] Formula: Styrene 28 wt%, Butadiene 71 wt%, VTES 1 wt%; Vinyl content 40 mol% Process: Anionic polymerization at 55℃, initiated by hydroxyethylpropyllithium, terminated by tetramethoxysilane, and coupled with a silane coupling agent; Product parameters: Mn=280,000, PDI=1.4, coupling degree 18%, Tg=-55℃.

[0023] Comparative Example 1 Commercial SSBR (unfunctionalized, hydrogen-terminated), styrene 30wt%, vinyl groups 45mol%, Mn=250,000, PDI=1.5.

[0024] Comparative Example 2 Single-terminal siloxane-functionalized SSBR, without side-chain functional groups, styrene 30wt%, vinyl 45mol%, Mn=250,000, PDI=1.5.

[0025] The SSBRs prepared in the examples and comparative examples were subjected to performance tests under the test conditions, and the test results are shown in Table 1.

[0026] Table 1. Performance comparison of multi-site synergistic functionalized SSBR in the examples and comparative examples Example 4 Application formulations and performance of thick-walled products for large engineering tires and aircraft tires Based on the multi-site functionalized SSBR of this invention, three typical thick product formulations were designed to adapt to the compression molding and vulcanization process of thick products, with the following corresponding properties: Formula 1: Heavy-duty mining tire tread compound (curing thickness 15mm) Components Dosage (parts by weight) Example 1: Multi-site functionalized SSBR 70 Natural rubber (NR) 30 precipitate 65 Carbon black N220 15 Silane coupling agent Si69 5.2 Zinc oxide 5 stearic acid 2 Anti-aging agent 4020 2 Anti-aging agent RD 1.5 Microcrystalline wax 1.5 Aromatic oils 8 Accelerator CZ 1.5 Sulfur 2.2

[0027] Tensile strength at 23℃: 28.2 MPa Elongation at break: 510% 300% constant tensile stress: 16.8 MPa Akron wear (1.6km / 27N): 0.078 cm³ 60℃ tanδ: 0.089 Heat generated by compression (100℃ / 25min): 27℃ Relative value of cut resistance: 135% (based on 100% of a standard SSBR formulation). Tensile strength retention rate after 100℃×24h heat aging: 92%

[0028] Components Dosage (parts by weight) Example 3 Multisite functionalized SSBR 60 Butadiene rubber (BR9000) 40 precipitate 55 Carbon Black N115 10 Silane coupling agent Si75 4.4 Zinc oxide 4 stearic acid 1.5 Anti-aging agent 4010NA 2 Anti-aging agent AW 1 Paraffinic oil 5 Accelerator NS 1.2 Sulfur 1.8

[0029] Tensile strength at 23℃: 26.5 MPa Elongation at break: 560% 0℃ tanδ: 0.29 60℃ tanδ: 0.085 Heat generated by compression (100℃ / 25min): 25℃ Low-temperature brittleness temperature: -66 ℃ Elongation retention at -40℃: 75% Stress retention rate at constant elongation at 100℃: 83% Flexural fatigue life (level 4 crack): ≥1.2 million cycles

[0030] Components Dosage (parts by weight) Example 2: Multi-site functionalized SSBR 50 Natural rubber (NR) 50 Carbon Black N330 50 precipitate 10 Silane coupling agent Si69 0.8 Zinc oxide 5 stearic acid 2.5 Anti-aging agent 4020 2.5 Anti-aging agent BLE 1.5 Aromatic oils 10 Accelerator DM 1.2 Sulfur 2.5 Properties of vulcanizate (molding at 150℃ for 45 minutes): Tensile strength at 23℃: 27.1 MPa Elongation at break: 530% Tear strength: 58 kN / m 60℃ tanδ: 0.095 Ozone aging resistance (50pphm, 20% elongation, 48h): No cracks. Elongation retention rate after 100℃×72h heat aging: 88%

Claims

1. A multi-site synergistic functionalized solution-polymerized styrene-butadiene rubber, which is a multifunctional SSBR with double-end capping and side-group grafting, wherein the SSBR molecular chain structure is mainly linear and slightly branched; Main chain components: 25%-40% by weight of polystyrene units, 58%-74% by weight of polybutadiene units, and 1%-3% by weight of side-functionalized comonomers; the molar proportion of vinyl structures formed by 1,2 polymerization in polybutadiene units is 35%-55%, and the polystyrene units and polybutadiene units are mainly randomly distributed in the molecular chain, with a small amount of block polystyrene at the chain ends. Functional group distribution: Initiator: amino / hydroxyalkyl polar functional group; Termination end: Trialkoxysilyl / epoxypropoxy reactive functional groups; Side groups: siloxane functional groups are grafted onto the side of the main chain, with an average functional group density of 0.5-2.0 groups per molecular chain; Molecular weight and distribution: Number average molecular weight is 180,000-320,000, and molecular weight distribution index is 1.3-1.8; After multifunctional group coupling, the branched / coupled component accounts for 10%-25% by weight.

2. The multi-site synergistic functionalized solution polymerized styrene-butadiene rubber according to claim 1, characterized in that... The amino polar functional group refers to dimethylaminopropyl, diethylaminopropyl, pyrrolylpropyl, piperidinylpropyl, morpholinopropyl, hexamethyleneiminopropyl, preferably hexamethyleneiminopropyl.

3. The multi-site synergistic functionalized solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that... The hydroxyalkyl polar functional group refers to hydroxyethyl, hydroxypropyl, and hydroxybutyl.

4. The multi-site synergistic functionalized solution polymerized styrene-butadiene rubber according to claim 1, characterized in that... The aforementioned trialkoxysilyl reactive functional group refers to trimethoxysilyl, trimethoxysilylpropyl, triethoxysilyl, triethoxysilylpropyl, and methyldimethoxysilyl; the aforementioned epoxypropoxy reactive functional group refers to epoxypropoxypropyltrimethoxysilyl, epoxypropoxypropyltriethoxysilyl, and epoxycyclohexylethyltrimethoxysilyl; preferably epoxypropoxypropyltrimethoxysilyl.

5. The multi-site synergistic functionalized solution polymerized styrene-butadiene rubber according to claim 1, characterized in that... The main chain side-grafted siloxane functional group refers to the monomers vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, styryltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane grafted onto the main chain side position, preferably vinyltriethoxysilane.

6. The multi-site synergistic functionalized solution-polymerized styrene-butadiene rubber according to claim 1, characterized in that... The multifunctional coupling is achieved by adding tin tetrachloride as a coupling agent and reacting for 20-30 minutes, with the degree of coupling controlled at 10%-25%.

7. A method for preparing multi-site synergistic functionalized solution polymerized styrene-butadiene rubber. An anionic solution polymerization method was employed, using a cyclohexane-n-hexane mixed solvent as the reaction medium. Precise structural control was achieved through five steps: functionalization initiation, stepwise copolymerization, side-group grafting, functionalization termination, and coupling. The specific process is as follows: Raw material refining: Styrene, butadiene monomers, and mixed solvents are refined through molecular sieves and activated alumina in series, controlling the water content to ≤5ppm and the polymerization inhibitor content to ≤1ppm; Initiation system: Use amino-functionalized organolithium initiators or hydroxyalkyl-functionalized organolithium initiators at a concentration of 0.5-1.5 mol / L, with an initiation efficiency ≥95%; Copolymerization reaction: Solvent, mixed monomers and polarity modifier are added to a high-pressure reactor. After heating to 50-65℃, initiator is added, and the reaction is carried out for 30-60 min. When the monomer conversion rate reaches 85% or more, vinyltriethoxysilane is added as a side-group functionalized monomer, and the reaction is continued for 20-40 min until the total conversion rate is ≥99%. Functionalization termination and coupling: First, add epoxypropoxypropyltrimethoxysilane for end-group capping reaction for 15-30 min, then add tin tetrachloride and react for 20-30 min, with the coupling degree controlled at 10-25%; Post-processing: High-temperature resistant antioxidant is added, followed by steam condensation, twin-screw extrusion dehydration, and vacuum drying to obtain the finished adhesive.

8. The method for preparing multi-site synergistic functionalized solution polymerized styrene-butadiene rubber according to claim 7, characterized in that... The amino-functionalized organolithium initiator is hexamethyleneiminepropyllithium.

9. The method for preparing multi-site synergistic functionalized solution polymerized styrene-butadiene rubber according to claim 7, characterized in that... The polarity modifier mentioned is diethylene glycol dimethyl ether.

10. The application of the functionalized SSBR of claim 1 in the tread and sidewall compounds of special engineering tires and aerospace tires.