A method for preparing a highly branched tri-hybrid arm bromobutyl rubber

Abstract

A preparation method of a highly branched three-hetero-arm brominated butyl rubber, comprising: adding a five-membered three-hetero-arm brominated grafting agent into a mixed solvent, stirring until completely dissolved to obtain a mixed solution; cooling, sequentially adding a diluent, isobutylene and isoprene into the mixed solution, fully stirring and mixing to obtain a polymerization reaction system, cooling again; mixing and aging the diluent and a co-initiator, then adding into the polymerization reaction system, fully stirring and reacting, adding a terminating agent, discharging, coagulating, washing, drying to obtain the highly branched three-hetero-arm brominated butyl rubber; the five-membered three-hetero-arm brominated grafting agent is a five-membered three-hetero-arm secondary and primary brominated star block copolymer composed of isoprene, 1,3-butadiene, styrene, a macromolecular brominated agent and a reactive brominated agent. The preparation method of the present application enables the butyl rubber to maintain sufficient raw rubber strength and good air tightness, and to give a balance of physical mechanical properties and vulcanization processing properties.

Description

Technical Field

[0001] This invention relates to a method for preparing highly branched tri-heteroarm brominated butyl rubber, specifically to a method for preparing highly branched tri-heteroarm brominated butyl rubber by graft modification of a five-membered tri-heteroarm star-shaped block copolymer of isoprene / butadiene / styrene / reactive brominator with secondary and primary brominated structures. Background Technology

[0002] Butyl rubber (IIR) is a cationic copolymer of isobutylene and a small amount of isoprene. It possesses excellent airtightness, damping properties, heat aging resistance, ozone resistance, and weather resistance, making it widely used in the manufacture of inner tubes, airtight layers, and vulcanizing bladders for automotive tires, thus becoming one of the most important synthetic rubber varieties. However, butyl rubber molecules are mainly composed of carbon-carbon single bonds with low unsaturation. The symmetrical arrangement of substituent methyl groups results in high crystallinity, poor molecular chain flexibility, slow stress release rate, slow vulcanization speed, poor adhesion, and poor compatibility with other general-purpose rubbers. These drawbacks make butyl rubber prone to excessive flow and deformation during processing, thus becoming a bottleneck for expanding the applications of butyl rubber materials.

[0003] Currently, brominated butyl rubber (BIIR) is produced by introducing bromine atoms into the molecular chain of butyl rubber (IIR) through an electrophilic substitution reaction under the influence of molecular bromine. Compared to IIR, BIIR, in addition to possessing the same excellent airtightness, not only increases the polarity of the molecular chain due to the introduction of bromine atoms, improving adhesion to other rubbers and allowing it to be used in any ratio with unsaturated rubbers such as natural rubber and styrene-butadiene rubber, but also generates additional crosslinking sites, enhancing the activity of the original double bonds, improving the vulcanization performance of the rubber compound, resulting in faster vulcanization and more diverse vulcanization methods; heat resistance is also improved. Therefore, BIIR is gradually replacing IIR in industrial products such as radial tires, tubeless tires, medical sealing devices, and chemical equipment linings, demonstrating broad industrial application value and prospects.

[0004] In recent years, researchers have discovered a star-branched butyl rubber composed of a high-molecular-weight branched structure and a low-molecular-weight linear structure. This star-branched butyl rubber can be brominated to obtain brominated star-branched butyl rubber. This brominated star-branched butyl rubber, due to its unique "three-dimensional network" branched structure and bromine atoms, possesses both a wide molecular weight distribution and excellent viscoelastic properties, as well as high raw rubber strength and fast vulcanization speed. In particular, it exhibits low melt viscosity, low processing energy consumption, low discharge temperature, low shrinkage, and long scorch time during processing, achieving a balanced unity of physical and mechanical properties and processing performance. Therefore, brominated star-branched butyl rubber has become one of the hot topics in future butyl rubber research.

[0005] CN112574333A provides a bromination process for star-branched butyl rubber, the process comprising: a) dissolving the star-branched butyl rubber in an aliphatic hydrocarbon to obtain a rubber solution; b) mixing the above rubber solution with a branching agent and a scavenging agent ethanol to obtain a mixed solution; c) adding an oxidizing agent hydrogen peroxide and a brominating agent Br2 to the above mixed solution, wherein the molar ratio of bromine to the unsaturated double bonds in the star-branched butyl rubber is [missing information]. Brominated star-branched butyl rubber is obtained by bromination, final neutralization, and product recovery. This process can dissolve the residual branching agent in the star-branched butyl rubber before bromination, preventing it from combining with the HBr byproducts generated during bromination, thereby improving neutralization efficiency and inhibiting the isomerization transformation from Type II secondary structure to Type III primary structure.

[0006] CN112011019A discloses a method for preparing halogenated bimodal star-branched butyl rubber. This method employs anionic polymerization to synthesize a poly(styrene-conjugated diene) block polymer, which is then coupled with silicon tetrachloride to obtain a four-armed star-shaped block polymer. The copolymer is dissolved and HCl gas is continuously introduced at -20 to 0°C for 3 to 12 hours to obtain a silicon- and chlorine-functionalized four-armed star-shaped branching agent. The silicon- and chlorine-functionalized four-armed star-shaped branching agent is dissolved in a solvent, isobutylene and isoprene are added, and the temperature is lowered to below -60°C. The main initiator and co-initiator are mixed, aged, and then added to the system. Polymerization is carried out under stirring for 3 to 30 minutes. A terminator is added to terminate the reaction, and the mixture is steamed under reduced pressure and vacuum dried. The sample is then halogenated to obtain halogenated bimodal star-shaped branched butyl rubber. The bimodal star-shaped branched butyl rubber prepared by this method exhibits low Mooney stress relaxation and lower intrinsic viscosity, demonstrating good processing performance.

[0007] CN 101353403B discloses a method for preparing star-branched polyisobutylene or butyl rubber. This method uses a polystyrene / isoprene block copolymer with terminal silanol groups or a polystyrene / butadiene block copolymer with terminal silanol groups as an initiator and grafting agent for cationic polymerization. The method involves direct participation in cationic polymerization in a mixed solvent of chloromethane / cyclohexane with a v:v ratio of 20–80 / 80–20 under temperature conditions of 0–100°C. The cationic polymerization is initiated by silanol groups, and the star-branched polyisobutylene or butyl rubber product is prepared through grafting reactions involving unsaturated chains.

[0008] CN 106749816A discloses a method for preparing brominated butyl rubber. The method first dissolves butyl rubber in n-alkane, then uses specific organic bromides such as phenyltrimethyltribromoamine, benzyltrimethyltribromoamine, or dibromoisocyanuric acid as brominating agents, and Br2 or HBr as bromination accelerators to carry out the bromination reaction in the solvent, thereby obtaining brominated butyl rubber. This method inhibits the molecular rearrangement of secondary bromine in brominated butyl rubber to form berberine bromine, thus increasing the content of secondary bromine structures in the brominated butyl rubber.

[0009] Wu Yibo et al. (Davang SH, et al. Skid resistant coatings for aircraft carrier decks[J]. Coat Technol, 1980, 52(671): 65-69.) disclosed a method for preparing a star-shaped branched butyl rubber with obvious bimodal structure by using poly(isoprene-styrene) block copolymer as a grafting agent through living anionic polymerization in an initiation system of 2-chloro-2,4,4-trimethylpentane / titanium tetrachloride / proton scavenger via cationic polymerization with activated carbon.

[0010] Synthetic Rubber Industry (2006, 29(4): A method for preparing brominated butyl rubber by dissolving butyl rubber (Polysar-301) in cycloalkanes and then brominating it with liquid bromine was disclosed. The effects of residence time and reaction temperature on the Mooney viscosity, degree of unsaturation, bromine content, and microstructure of the product were investigated. The results showed that the Mooney viscosity and degree of unsaturation decreased sharply when the residence time was less than 2 min, and the changes were not significant after 2 min. Increasing the reaction temperature decreased the Mooney viscosity, but had little effect on the degree of unsaturation. Increasing the reaction temperature and extending the residence time not only benefited the increase of bromine content in the product, but also facilitated the rearrangement of its molecular structure, i.e., a transfer from the secondary allyl bromide configuration to the more stable primary allyl bromide configuration.

[0011] In the aforementioned prior art, star-branched butyl rubber or butyl rubber dissolved and brominated to obtain brominated butyl rubber exhibits a larger molecular weight distribution, increased stress relaxation rate, and faster vulcanization speed, demonstrating good processability. However, these methods still have certain limitations. During the bromination process of butyl rubber, hydrogen bromide, a byproduct, is easily generated, leading to the loss of remaining bromine and reducing the utilization rate of bromine. This results in a significant isomerization of the Type III secondary structure in the brominated butyl rubber towards the Type III primary structure, thus affecting the processing performance of the brominated butyl rubber. Furthermore, hydrogen bromide is highly corrosive, leading to a deterioration in the quality of the brominated butyl rubber and potentially causing environmental pollution and human health and safety issues. Summary of the Invention

[0012] The purpose of this invention is to provide a method for preparing highly branched tri-heteroarm brominated butyl rubber. This method first uses alkyllithium as an initiator and isoprene, styrene, butadiene, a reactive brominating agent, and a macromolecular brominating agent as reacting monomers. A five-membered tri-heteroarm brominated star copolymer is prepared through three-stage polymerization and coupling with a coupling agent. This five-membered tri-heteroarm brominated star copolymer is then used as a grafting agent to undergo cationic polymerization with isobutylene and isoprene to prepare highly branched tri-heteroarm brominated butyl rubber. This method solves the problems of long vulcanization scorch time, low vulcanization rate, and slow stress relaxation rate that easily occur during the processing of butyl rubber. Simultaneously, it ensures that the highly branched tri-heteroarm brominated butyl rubber has sufficient raw rubber strength and good airtightness, achieving a balance between the physical and mechanical properties and processing performance of the highly branched tri-heteroarm brominated butyl rubber.

[0013] Unless otherwise specified, "%" in this invention refers to mass percentage.

[0014] To achieve the above objectives, the present invention provides a method for preparing highly branched tri-heteroarm brominated butyl rubber, the method comprising the following steps:

[0015] S1: Add the pentagonal tri-arm brominated grafting agent to the mixed solvent and stir thoroughly until the pentagonal tri-arm brominated grafting agent is completely dissolved to obtain a mixed solution;

[0016] S2: Cool down, add diluent, isobutylene and isoprene to the mixed solution in step S1 in sequence, stir and mix thoroughly to obtain the polymerization reaction system, and cool down again;

[0017] S3: Mix the diluent and co-initiator and age them. Then add them to the polymerization reaction system of step S2 and stir the reaction thoroughly. Add the terminator, discharge the material, coagulate, wash and dry to obtain highly branched tri-heteroarm brominated butyl rubber.

[0018] The characteristic feature is that the five-membered three-heteroarm brominated grafting agent is a five-membered three-heteroarm secondary and primary brominated star-shaped block copolymer composed of isoprene, 1,3-butadiene, styrene, macromolecular brominated agent and reactive brominated agent, and its general structural formula is shown in Formula I:

[0019]

[0020] Wherein, Bu is tert-butyl; IR is isoprene homopolymer block; BR is 1,3-butadiene homopolymer block; SBR is styrene-butadiene random block copolymer; m is the number of repeating units, m is an integer ≥1; the number average molecular weight (Mn) of the five-membered three-heteroarm brominated grafting agent is 90,000 to 110,000, and the molecular weight distribution (Mw / Mn) is 14.15 to 15.62.

[0021] In the preparation method of the highly branched tri-heteroarm brominated butyl rubber of the present invention, in step S1, the mass ratio of the mixed solvent and the five-membered tri-heteroarm brominated grafting agent is 100-200:4-7.

[0022] In the preparation method of the highly branched tri-heteroarm brominated butyl rubber of the present invention, in step S1, the mixed solvent includes a diluent and a solvent, and the volume ratio of the diluent and the solvent is 70-30 / 30-70.

[0023] In the preparation method of the highly branched tri-arm brominated butyl rubber of the present invention, in step S2, the temperature is cooled to -80 to -90°C.

[0024] In the preparation method of the highly branched triheteroarm brominated butyl rubber of the present invention, in step S2, the mass ratio of the diluent, isobutylene and isoprene is 100-200:85-90:6-8.

[0025] In the preparation method of the highly branched tri-heteroarm brominated butyl rubber of the present invention, in step S2, the temperature is lowered again to -100 to -90°C.

[0026] In the preparation method of the highly branched tri-heteroarm brominated butyl rubber of the present invention, in step S3, the mass ratio of the diluent, co-initiator and terminator is 10-20: 0.1-0.5: 5-10.

[0027] In the preparation method of the highly branched tri-arm brominated butyl rubber of the present invention, in step S3, the aging temperature is -95℃ to -85℃ and the aging time is 20 to 30 minutes.

[0028] The method for preparing highly branched tri-heteroarm brominated butyl rubber of the present invention specifically includes the following steps:

[0029] Preparation of macromolecular brominating agent: Taking 100 parts by mass of reactive brominating agent, firstly, add 200-300 parts of solvent, 100 parts of bromovinylbenzene, and 0.2-0.5 parts of molecular weight regulator sequentially to the reaction vessel after inert gas replacement. Stir and mix, heat, and when the reaction vessel temperature reaches 70-90℃, add 0.05-0.5 parts of the first initiator. React for 3.0-5.0 hours, at which point the conversion rate of bromovinylbenzene reaches 100%. Then, add 1-5 parts of 1,3-butadiene to the reaction vessel for end-capping, and react for 40-60 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain macromolecular brominating agent.

[0030] Preparation of the five-membered three-hetero-arm brominated grafting agent: Based on 100% of the mass of the reactive brominizing agent, first add 100wt%–200wt% solvent, 30wt%–40wt% isoprene, 0.1wt%–0.4wt% structure modifier, and second initiator sequentially to reactor A after inert gas replacement. Heat to 60–70℃ and react for 30–40 min. Then add 30wt%–40wt% reactive brominizing agent to reactor A and react for 70–90 min until no free monomers are present.

[0031] Simultaneously, 100wt%–200wt% solvent, 10wt%–20wt% styrene, 20wt%–30wt% 1,3-butadiene, 0.2wt%–0.5wt% structure modifier, and a second initiator are added sequentially to reactor B after inert gas purging. The temperature is raised to 60–70℃, and the reaction is carried out for 60–80 min. Then, 20wt%–30wt% isoprene is added to reactor B, and the reaction is carried out for 30–40 min to form -IR-SBR- segments. Finally, 60wt%–70wt% reactive brominating agent and 30wt%–50wt% macromolecular brominating agent are added sequentially to reactor B, and the reaction is carried out for 120–140 min until no free monomers are present.

[0032] Simultaneously, 100wt%–200wt% solvent, 30wt%–40wt% 1,3-butadiene, 0.1wt%–0.3wt% structure modifier, and a second initiator are sequentially added to reactor C after inert gas purging. The temperature is raised to 40–50℃, and the reaction is carried out for 50–60 min to form -BR- segments. Then, 50wt%–70wt% macromolecular brominating agent is added to reactor C, and the reaction is carried out for 70–90 min until no free monomers are present.

[0033] Finally, the materials from reactors B and C are added to reactor A, the temperature is raised to 80-90°C, a coupling agent is added to carry out the coupling reaction, and after reacting for 100-130 minutes, the coupled reaction mixture is treated with water, and then wet coagulation and drying are performed to obtain the five-membered three-hetero-arm brominated grafting agent.

[0034] The method for preparing highly branched triheteroarm brominated butyl rubber of the present invention, wherein the molecular weight regulator may be selected from at least one of tert-decanethiol, tert-dodecanethiol, tert-tetradecanethiol, and tert-hexadecanethiol, preferably tert-dodecanethiol.

[0035] The method for preparing highly branched tri-arm brominated butyl rubber of the present invention, wherein the first initiator is an organic peroxide selected from at least one of dicumyl peroxide, cumyl hydroperoxide, benzoyl peroxide (BPO) and di-tert-butyl peroxide, preferably benzoyl peroxide (BPO).

[0036] The method for preparing highly branched triheteroarm brominated butyl rubber of the present invention uses a structure modifier that is a polar organic compound. This compound produces a solvation effect in the polymerization system, enabling the regulation of the reactivity ratio between styrene and isoprene, thus allowing them to copolymerize randomly. This type of polar organic compound is selected from at least one of diethylene glycol dimethyl ether (DGE), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME), and triethylamine, preferably tetrahydrofuran (THF).

[0037] In the method for preparing highly branched triheteroarm brominated butyl rubber of the present invention, the second initiator is a hydrocarbon monolithium compound, namely RLi, wherein R is a saturated aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic group, or a complex group of the above groups containing 1 to 20 carbon atoms. This hydrocarbon monolithium compound is selected from at least one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthenelithium, cyclohexyllithium, and dodecyllithium, preferably n-butyllithium. The amount of the second initiator added is determined by the molecular weight of the designed polymer.

[0038] The method for preparing highly branched tri-hetero-arm brominated butyl rubber of the present invention includes a coupling agent that is a halosilane selected from at least one of tert-butyltrichlorosilane and tert-butyltribromosilane, preferably tert-butyltrichlorosilane. The amount of coupling agent used depends on the amount of the second initiator, and the molar ratio of the coupling agent to the second initiator is 1:1 to 5:1.

[0039] The method for preparing highly branched tri-arm brominated butyl rubber of the present invention, wherein the reactive brominating agent is selected from at least one of p-bromomethylstyrene and p-chloromethylstyrene, preferably p-bromomethylstyrene.

[0040] In the preparation method of the highly branched tri-heteroarm brominated butyl rubber of the present invention, the polymerization reaction is carried out in an oxygen-free and anhydrous environment, preferably in an inert gas environment. Both the polymerization reaction and the dissolution process are completed in a hydrocarbon solvent. The solvent described in the present invention is a hydrocarbon solvent, which includes straight-chain alkanes, aromatics, and cycloalkanes. This hydrocarbon solvent is selected from one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene, with cyclohexane being preferred.

[0041] The method for preparing highly branched tri-arm brominated butyl rubber of the present invention includes a diluent that is a haloalkane, wherein the halogen atom in the haloalkane can be chlorine, bromine, or fluorine; and the number of carbon atoms in the haloalkane is C1-C4. This haloalkane is selected from at least one of chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane, preferably dichloromethane.

[0042] The method for preparing highly branched triheteroarm brominated butyl rubber of the present invention comprises a co-initiator composed of alkyl aluminum halides and protic acids in different proportions. The alkyl aluminum halide is selected from at least one of diethylaluminum chloride, diisobutylaluminum chloride, dichloromethylaluminum, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, dichloro-n-propylaluminum, dichloroisopropylaluminum, dimethylaluminum chloride, and ethylaluminum chloride, preferably sesquiethylaluminum chloride. The protic acid is selected from one of HCl, HF, HBr, H2SO4, H2CO3, H3PO4, and HNO3, preferably HCl. The molar ratio of the protic acid to the alkyl aluminum halide is 0.05:1 to 0.2:1.

[0043] The method for preparing highly branched triheteroarm brominated butyl rubber of the present invention may, for example, but not limited to, at least one of methanol, ethanol, and butanol.

[0044] The present invention can also be described in detail below:

[0045] In detail, the specific preparation process of the highly branched tri-heteroarm brominated butyl rubber of the present invention includes the following steps:

[0046] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0047] Preparation of macromolecular brominating agent: Taking 100 parts by mass of reactive brominating agent, firstly, in a 15L stainless steel reactor with a jacket, purge with inert gas 2-4 times. Then, add 200-300 parts of solvent, 100 parts of bromovinylbenzene, and 0.2-0.5 parts of molecular weight regulator to the reactor in sequence. Stir and mix, heat, and when the reactor temperature reaches 70-90℃, add 0.05-0.5 parts of the first initiator. React for 3.0-5.0 hours, at which point the conversion rate of bromovinyl monomer reaches 100%. Then, add 1-5 parts of 1,3-butadiene to the reactor for end-capping, and react for 40-60 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain macromolecular brominating agent.

[0048] Preparation of the pentagonal tri-arm brominated grafting agent: Using 100% of the reactive brominating agent by mass, first, in a jacketed 15L stainless steel reactor A, purge with argon gas 2-4 times. Then, sequentially add 100wt%-200wt% solvent, 30wt%-40wt% isoprene, 0.1wt%-0.4wt% structure modifier, and a second initiator to the reactor. Heat to 60-70℃ and react for 30-40 min. Subsequently, add 30wt%-40wt% of the reactive brominating agent to reactor A and react for 7 minutes. React for 0–90 minutes until no free monomers remain. Simultaneously, in a 15L stainless steel reactor B, purge the system with argon gas 2–4 times, then add 100 wt%–200 wt% solvent, 10 wt%–20 wt% styrene, 20 wt%–30 wt% 1,3-butadiene, 0.2 wt%–0.5 wt% structure modifier, and a second initiator. Heat to 60–70°C and react for 60–80 minutes. Then add 20 wt%–30% isoprene to reactor B and react for 30–40 minutes. n, forming -IR-SBR- segments, and finally adding 60wt%~70wt% reactive brominating agent and 30wt%~50wt% macromolecular brominating agent sequentially to reactor B, reacting for 120~140min until no free monomers are present; simultaneously, in a 15L stainless steel reactor C, purging the system with argon gas 2~4 times, and sequentially adding 100wt%~200wt% solvent, 30wt%~40wt% 1,3-butadiene, 0.1wt%~0.3wt% structure modifier, and the second initiator. The agent is heated to 40-50℃ and reacted for 50-60 minutes to form -BR- segments; then 50wt%-70wt% of macromolecular brominating agent is added to reactor C and reacted for 70-90 minutes until no free monomers are present; finally, the materials from reactors B and C are added to reactor A, heated to 80-90℃, and a coupling agent is added to carry out a coupling reaction. After reacting for 100-130 minutes, the coupled reaction mixture is treated with water, and the gel is wet-coagulated and dried to obtain the five-membered three-hetero-arm bromination grafting agent.

[0049] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Based on 100% of the total mass of the reactants, first, in a jacketed 4L stainless steel reactor, purge with nitrogen 3-5 times, then add 100wt%-200wt% mixed solvent (diluent / solvent V:V ratio of 70-30 / 30-70), 4wt%-7wt% pentagonal tri-heteroarm brominated grafting agent, and stir to dissolve for 60-80 minutes until the grafting agent is completely dissolved; then, when the temperature is lowered to -80 to -90℃, add 100wt%-200wt% diluent, 200wt% of nitrogen, 4wt%-7wt% of pentagonal tri-heteroarm brominated grafting agent, and stir to dissolve for 60-80 minutes until the grafting agent is completely dissolved; then, when the temperature is lowered to -80 to -90℃, add 100wt%-200wt% diluent, 200wt% of nitrogen, 4wt%-7wt% of diluent ... The polymer system is mixed with 85wt%–90wt% isobutylene and 6wt%–8wt% isoprene. The mixture is stirred until the polymerization temperature drops to -100 to -90℃. Then, 10wt%–20wt% diluent and 0.1wt%–0.5wt% co-initiator are mixed and aged at -95 to -85℃ for 20–30 minutes. The mixture is then added to the polymerization system and stirred for 5.0–7.0 hours. Finally, 5wt%–10wt% terminator is added. The mixture is then discharged, coagulated, washed, and dried to obtain a highly branched tri-heteroarm brominated butyl rubber product.

[0050] The pentagonal triheteroarm brominated grafting agent of the present invention is a pentagonal triheteroarm secondary and primary brominated star-shaped block copolymer composed of isoprene, 1,3-butadiene, styrene, macromolecular brominated agent and reactive brominated agent, and its general structural formula is shown in Formula I:

[0051]

[0052] Wherein: Bu is tert-butyl; IR is isoprene homopolymer block; BR is 1,3-butadiene homopolymer block; SBR is styrene-butadiene random block copolymer; m is the number of repeating units. The number-average molecular weight (Mn) of the five-membered triheteroarm brominated grafting agent is 90,000–110,000, and the molecular weight distribution (Mw / Mn) is 14.15–15.62.

[0053] This invention first involves the free radical polymerization of bromovinylbenzene to generate a macromolecular brominator with anionic reactivity. Secondly, using anionic polymerization with isoprene, styrene, 1,3-butadiene, the macromolecular brominator, and the reactive brominator as monomers, a three-stage polymerization process is employed. Subsequently, a five-membered tri-hetero-arm brominated grafting agent is prepared by coupling with a trihalosilane coupling agent. Finally, this five-membered tri-hetero-arm brominated grafting agent is combined with isobutylene and isoprene in a cationic polymerization system catalyzed by alkyl aluminum halide and a protic acid to prepare a highly branched tri-hetero-arm brominated butyl rubber with a highly branched structure, a tri-hetero-arm structure, and secondary and primary bromine structures.

[0054] The five-membered tri-heteroarm brominated grafting agent prepared by this invention combines the microstructures of the tri-heteroarm star structure, secondary and primary bromine structures, BR segments, IR segments and SBR segments on a single macromolecular chain and works synergistically.

[0055] First, this fully primary bromine structure is introduced into the butyl rubber backbone through a grafting process, which solves the problem of difficult vulcanization caused by the lack of unsaturated double bonds in butyl rubber, shortens the scorch time and ensures the safety of scorch, accelerates the vulcanization speed and increases the degree of vulcanization.

[0056] Secondly, by utilizing the fact that BR, IR, and SBR segments contain a large number of unsaturated double bonds, the butyl rubber main chain can be connected at multiple points during the grafting process, forming a highly branched butyl rubber. Furthermore, the different molecular chain structures of each arm in the three heterogeneous arms significantly disrupt the regularity of the butyl rubber molecular chain during grafting, greatly increasing the disorder of the molecular chain segments. This allows the butyl rubber to obtain good viscoelastic properties, possess a fast stress relaxation rate, and improve its processing performance.

[0057] Finally, the -SBR- segment macromolecular brominator and reactive brominator in the five-membered tri-heteroarm brominated grafting agent contain a certain amount of benzene rings. Benzene rings have high rigidity and steric hindrance, which can prevent the decrease in strength and airtightness caused by increased branching of butyl rubber, ensuring sufficient strength and good airtightness of the butyl rubber, thus achieving a balance between the vulcanization characteristics, processability, strength, and airtightness of butyl rubber. This invention provides a method for preparing highly branched tri-heteroarm brominated butyl rubber, which features a short process flow, stable vulcanization process, safety and environmental friendliness, and suitability for industrial production.

[0058] In summary, the present invention has the following beneficial effects:

[0059] 1. The five-membered three-arm brominated grafting agent of the present invention adopts anionic polymerization instead of the ionic substitution reaction in the prior art, thereby avoiding bromine structure rearrangement, improving the stability of the secondary and primary bromine structures of highly branched three-hetero-arm brominated butyl rubber, solving the problem of difficult vulcanization of butyl rubber due to the lack of unsaturated double bonds, shortening the scorch time and ensuring the safety of scorch, accelerating the vulcanization speed, increasing the degree of vulcanization, and improving the vulcanization efficiency.

[0060] 2. The five-element three-arm brominated grafting agent of the present invention uses a reactive brominated agent with anionic reaction characteristics for anionic polymerization. No byproduct HBr is generated during the entire reaction process, which improves the utilization rate of bromine in brominated highly branched butyl rubber.

[0061] 3. The five-membered three-arm bromide grafting agent of the present invention does not generate the byproduct HBr during the entire reaction process, which reduces the harm to humans and the environment, eliminates the need for alkaline washing and recovery of the byproduct HBr, thereby shortening the process flow and reducing production costs.

[0062] 4. The five-membered three-arm brominated grafting agent of the present invention utilizes the characteristics of the three-heterogeneous-arm star structure, secondary and primary bromine structures, BR segments, IR segments and SBR segments to form multi-point connections and obtain highly branched butyl rubber during the grafting process of butyl rubber. This structural feature enables butyl rubber to obtain good viscoelastic properties, has a fast stress relaxation rate, and improves the processing performance of butyl rubber. Furthermore, because the SBR segments and reactive brominizing agents contain benzene ring structures, they can avoid the decrease in strength and air tightness caused by the increased branching degree of butyl rubber, ensuring that butyl rubber has sufficient strength and good air tightness, and achieving a balance between the vulcanization characteristics, processability, strength and air tightness of butyl rubber.

[0063] 5. The five-membered three-arm brominated grafting agent of the present invention is a new type of safe and environmentally friendly compound with no emissions of air pollutants (VOCs) and byproduct HBr. Its preparation method has the characteristics of short process flow, stable bromine structure, safety and environmental protection, and suitability for industrial production. Detailed Implementation

[0064] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0065] (1) Source of raw materials:

[0066] Styrene, 1,3-butadiene, polymer grade, China National Petroleum Corporation Lanzhou Petrochemical Company;

[0067] Isobutylene and isoprene, polymer grade, Zhejiang Xinhui New Materials Co., Ltd.

[0068] p-Bromomethylstyrene, polymer grade, Shanghai Yi'en Chemical Technology Co., Ltd.;

[0069] Bromovinylbenzene, Polymerization Grade, Shanghai Yishi Chemical Co., Ltd.

[0070] Benzoyl peroxide (BPO), Lanzhou Additives Factory;

[0071] n-Butyllithium, 98% purity, Nanjing Tonglian Chemical Co., Ltd.

[0072] tert-Butyltrichlorosilane, 98% purity, Nanjing Tonglian Chemical Co., Ltd.

[0073] Sesquiethyl aluminum chloride, 98% purity, Bailingwei Technology Co., Ltd.

[0074] All other reagents are commercially available industrial products.

[0075] (2) Analysis and testing methods:

[0076] Bromine content determination: Weigh 10 mg of sample and use a Q600 TG / DTG thermogravimetric analyzer at a heating rate of 10℃ / min in a nitrogen atmosphere with a flow rate of 50 mL / min to perform thermal degradation of the sample. The first stage of thermal degradation involves the debromination of bromine-containing units in the sample to form HBr. The bromine content (X) in the sample is then inferred from the percentage of HBr removed, using the following formula:

[0077]

[0078] In the formula: Y is the percentage content of the sample at 220℃; 79.904 is the relative atomic mass of bromine; 1.008 is the relative atomic mass of hydrogen.

[0079] Molecular weight and its distribution were determined using a Waters 2414 gel permeation chromatography (GPC) system (USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 μL, the elution time was 40 min, and the flow rate was 1 mL / min. -1 .

[0080] Mooney stress relaxation determination: A GT-7080S2 Mooney viscometer was used, and the measurement was performed at 125℃ (1+8) using a large rotor, following the method in GB / T1232.1-2000. After the Mooney viscosity test, the rotor was stopped quickly (within 0.1 seconds), and the decrease in Mooney viscosity value over time was recorded. The torque within 0.1 seconds of rotor stop was set as 100%, and the stress relaxation behavior of the rubber was expressed using t80 (the time taken for 80% of the torque to decay (remaining 20%)) and X30 (the percentage of torque remaining 30 seconds after the rotor stops rotating).

[0081] Characterization of branching degree: Branching degree = molecular weight of polymer after branching / molecular weight of polymer before branching.

[0082] Vulcanization characteristics: tested according to GB / T 16584—1996.

[0083] Air tightness determination: An automated air tightness tester was used to determine the air permeability number according to ISO 2782:1995.

[0084] The test gas was N2, the test temperature was 23℃, and the test sample was a circular sea sheet with a diameter of 8cm and a thickness of 1mm.

[0085] Tensile strength: The method specified in standard GB / T528-2009 shall be applied.

[0086] Example 1

[0087] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0088] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 2000g of cyclohexane, 1000g of bromovinylbenzene, and 2.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 70℃, 0.5g of BPO was added, and the reaction was carried out for 3.0 hours. Then, 10g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 40 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0089] Preparation of the pentagonal trihexylidene brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged twice. Then, 1000g of cyclohexane, 300g of isoprene, and 1.0g of THF were added sequentially. The temperature was raised to 60℃, and 14.5mmol of n-butyllithium was added to initiate the reaction for 30 minutes. Subsequently, 400g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 90 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, the system was purged twice with argon gas. Then, 1000g of cyclohexane, 100g of styrene, 200g of 1,3-butadiene, and 2.0g of... THF was heated to 60°C, and 30.5 mmol of n-butyllithium was added to initiate a reaction for 60 min. Then, 200 g of isoprene was added to reactor B, and the reaction was continued for 30 min to form the -IR-SBR- segment. Finally, 600 g of p-bromomethylstyrene and 300 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction was continued for 120 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged twice with argon gas, and 1000 g of cyclohexane, 300 g of 1,3-butadiene, and 1.0 g of... THF was heated to 40°C, and 16.5 mmol of n-butyllithium was added to initiate a reaction for 50 min, forming -BR- segments. Then, 500 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 70 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, heated to 80°C, and 65.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 100 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm bromination grafting agent (Mn = 92000, Mw / Mn = 14.15).

[0090] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. Then, 150g of dichloromethane, 350g of cyclohexane, and 25.0g of pentagonal tri-heteroarm brominated grafting agent were added to the reactor and stirred for 60 minutes until completely dissolved. The temperature was then lowered to -80℃, followed by the sequential addition of 500g of dichloromethane, 450g of isobutylene, and 30.0g of isoprene. The mixture was stirred until the polymerization system temperature dropped to -90℃. Then, 50g of dichloromethane, 1.23g of sesquiethylaluminum chloride, and 0.015g of HCl were mixed and aged at -85℃ for 20 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.0 hours. Finally, 25g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0091] Example 2

[0092] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0093] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 2200g of cyclohexane, 1000g of bromovinylbenzene, and 2.5g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 74℃, 1.0g of BPO was added, and the reaction was carried out for 3.3 hours. Then, 20g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 44 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0094] Preparation of the pentagonal trihexy-arm brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged twice. Then, 1200g of cyclohexane, 310g of isoprene, and 1.5g of THF were added sequentially. The temperature was raised to 62℃, and 18.3mmol of n-butyllithium was added to initiate the reaction for 32 minutes. Subsequently, 380g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 85 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, the system was purged twice with argon gas. Then, 1200g of cyclohexane, 120g of styrene, 220g of 1,3-butadiene, and 3.0g of... THF was heated to 62°C, and 35.6 mmol of n-butyllithium was added to initiate a reaction for 64 min. Then, 220 g of isoprene was added to reactor B, and the reaction continued for 32 min to form the -IR-SBR- segment. Finally, 620 g of p-bromomethylstyrene and 330 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction continued for 126 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged twice with argon gas, and 1200 g of cyclohexane, 310 g of 1,3-butadiene, and 1.5 g of... THF was heated to 42°C, and 19.5 mmol of n-butyllithium was added to initiate a reaction for 52 min, forming -BR- segments. Then, 550 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 73 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, and the temperature was raised to 82°C. 100.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 105 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm bromination grafting agent (Mn = 96000, Mw / Mn = 14.52).

[0095] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged three times. Then, 200g of dichloromethane, 300g of cyclohexane, and 22.0g of a five-membered tri-heteroarm brominated grafting agent were added to the reactor and stirred for 63 minutes until completely dissolved. The temperature was then lowered to -82℃, and 600g of dichloromethane, 445g of isobutylene, and 33.0g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -92℃. Then, 60g of dichloromethane, 1.41g of sesquiethylaluminum chloride, and 0.032g of HCl were mixed and aged at -87℃ for 23 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.5 hours. Finally, 30g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0096] Example 3

[0097] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0098] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 2400g of cyclohexane, 1000g of bromovinylbenzene, and 3.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 78℃, 2.0g of BPO was added, and the reaction was carried out for 3.6 hours. Then, 30g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 47 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0099] Preparation of the pentagonal trihexylidene brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged three times. Then, 1400g of cyclohexane, 330g of isoprene, and 2.0g of THF were added sequentially. The temperature was raised to 64℃, and 20.6mmol of n-butyllithium was added to initiate the reaction for 34 min. Subsequently, 360g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 80 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged three times. Then, 1400g of cyclohexane, 140g of styrene, 240g of 1,3-butadiene, and 3.5g of... THF was heated to 64°C, and 40.6 mmol of n-butyllithium was added to initiate a reaction for 68 min. Then, 240 g of isoprene was added to reactor B, and the reaction proceeded for 34 min to form the -IR-SBR- segment. Finally, 640 g of p-bromomethylstyrene and 380 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction proceeded for 130 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged three times with argon gas, and 1400 g of cyclohexane, 330 g of 1,3-butadiene, and 2.0 g of... THF was heated to 44°C, and 26.5 mmol of n-butyllithium was added to initiate a reaction for 54 min, forming -BR- segments. Then, 600 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 78 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, and the temperature was raised to 84°C. 170.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 110 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm brominated grafting agent (Mn = 99000, Mw / Mn = 14.93).

[0100] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. Then, 300g of dichloromethane, 200g of cyclohexane, and 26.0g of pentagonal tri-heteroarm brominated grafting agent were added to the reactor and stirred for 66 minutes until completely dissolved. The temperature was then lowered to -85℃, followed by the sequential addition of 700g of dichloromethane, 440g of isobutylene, and 34.0g of isoprene. The mixture was stirred until the polymerization system temperature dropped to -95℃. Then, 70g of dichloromethane, 1.65g of sesquiethylaluminum chloride, and 0.047g of HCl were mixed and aged at -90℃ for 26 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 6.0 hours. Finally, 35g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0101] Example 4

[0102] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0103] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 2600g of cyclohexane, 1000g of bromovinylbenzene, and 3.5g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 80℃, 3.0g of BPO was added, and the reaction was carried out for 4.0 hours. Then, 35g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 50 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0104] Preparation of the pentagonal trihexylidene brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged three times. Then, 1600g of cyclohexane, 350g of isoprene, and 3.0g of THF were added sequentially. The temperature was raised to 66℃, and 26.6mmol of n-butyllithium was added to initiate the reaction for 36 minutes. Subsequently, 340g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 77 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, the system was purged three times with argon gas. Then, 1600g of cyclohexane, 160g of styrene, 270g of 1,3-butadiene, and 4.0g of... THF was heated to 66°C, and 45.6 mmol of n-butyllithium was added to initiate a reaction for 70 min. Then, 260 g of isoprene was added to reactor B, and the reaction continued for 36 min to form the -IR-SBR- segment. Finally, 660 g of p-bromomethylstyrene and 400 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction continued for 134 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged three times with argon gas, and 1600 g of cyclohexane, 350 g of 1,3-butadiene, and 2.4 g of... THF was heated to 46°C, and 30.5 mmol of n-butyllithium was added to initiate a reaction for 56 min, forming -BR- segments. Then, 630 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 80 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, heated to 85°C, and 220.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 115 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm brominated grafting agent (Mn = 103000, Mw / Mn = 15.14).

[0105] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. Then, 700g of dichloromethane, 300g of cyclohexane, and 28.0g of pentagonal tri-heteroarm brominated grafting agent were added to the reactor and stirred for 70 minutes until completely dissolved. The temperature was then lowered to -87℃, followed by the addition of 800g of dichloromethane, 435g of isobutylene, and 37.0g of isoprene. The mixture was stirred until the polymerization system temperature dropped to -96℃. Then, 80g of dichloromethane, 1.82g of sesquiethylaluminum chloride, and 0.058g of HCl were mixed and aged at -92℃ for 28 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 6.3 hours. Finally, 40g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0106] Example 5

[0107] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0108] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged four times. Then, 2800g of cyclohexane, 1000g of bromovinylbenzene, and 4.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 85℃, 3.5g of BPO was added, and the reaction was carried out for 4.0hr. Then, 40g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 58min until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0109] Preparation of the pentagonal trihexylidene brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged four times. Then, 1800g of cyclohexane, 370g of isoprene, and 3.5g of THF were added sequentially. The temperature was raised to 68℃, and 30.6mmol of n-butyllithium was added to initiate the reaction for 38 minutes. Subsequently, 320g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 74 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, the system was purged with argon gas four times. Then, 1800g of cyclohexane, 180g of styrene, 290g of 1,3-butadiene, and 4.5g of... THF was heated to 68°C, and 50.6 mmol of n-butyllithium was added to initiate a reaction for 75 min. Then, 280 g of isoprene was added to reactor B, and the reaction continued for 38 min to form the -IR-SBR- segment. Finally, 680 g of p-bromomethylstyrene and 460 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction continued for 137 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged four times with argon gas, and 1800 g of cyclohexane, 370 g of 1,3-butadiene, and 2.7 g of... THF was heated to 48°C, and 35.5 mmol of n-butyllithium was added to initiate a reaction for 58 min, forming -BR- segments. Then, 660 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 85 min until no free monomers remained. Finally, the materials from reactors B and C were added to reactor A, heated to 88°C, and 300.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 120 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm brominated grafting agent (Mn = 106000, Mw / Mn = 15.35).

[0110] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged four times. Then, 600g of dichloromethane, 400g of cyclohexane, and 31.0g of pentagonal tri-heteroarm brominated grafting agent were added to the reactor and stirred for 76 minutes until completely dissolved. The temperature was then lowered to -88℃, followed by the addition of 900g of dichloromethane, 430g of isobutylene, and 39.0g of isoprene. The mixture was stirred until the polymerization system temperature dropped to -98℃. Then, 90g of dichloromethane, 1.95g of sesquiethylaluminum chloride, and 0.067g of HCl were mixed and aged at -93℃ for 29 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 6.6 hours. Finally, 45g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0111] Example 6

[0112] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0113] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged four times. Then, 3000g of cyclohexane, 1000g of bromovinylbenzene, and 5.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 90℃, 4.0g of BPO was added, and the reaction was carried out for 5.0hr. Then, 50g of 1,3-butadiene was added to the reactor for end-capping, and the reaction was carried out for 60min until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0114] Preparation of the pentagonal trihexylidene brominated grafting agent: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged four times. Then, 2000g of cyclohexane, 400g of isoprene, and 4.0g of THF were added sequentially. The temperature was raised to 70℃, and 40.6mmol of n-butyllithium was added to initiate the reaction for 40min. Subsequently, 300g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 70min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged four times. Then, 2000g of cyclohexane, 200g of styrene, 300g of 1,3-butadiene, and 5.0g of... THF was heated to 70°C, and 60.6 mmol of n-butyllithium was added to initiate a reaction for 80 min. Then, 300 g of isoprene was added to reactor B, and the reaction was continued for 40 min to form the -IR-SBR- segment. Finally, 700 g of p-bromomethylstyrene and 500 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction was continued for 140 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged four times with argon gas, and 2000 g of cyclohexane, 400 g of 1,3-butadiene, and 3.0 g of... THF was heated to 50°C, and 40.5 mmol of n-butyllithium was added to initiate a reaction for 60 min, forming -BR- segments. Then, 700 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 90 min until no free monomers remained. Finally, the materials from reactors B and C were added to reactor A, heated to 90°C, and 400.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 130 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain a five-membered three-hetero-arm brominated grafting agent (Mn = 109000, Mw / Mn = 15.62).

[0115] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged four times. Then, 300g of dichloromethane, 700g of cyclohexane, and 35.0g of pentagonal tri-heteroarm brominated grafting agent were added to the reactor and stirred for 80 minutes until completely dissolved. The temperature was then lowered to -90℃, and 1000g of dichloromethane, 425g of isobutylene, and 40.0g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -100℃. Then, 100g of dichloromethane, 2.05g of sesquiethylaluminum chloride, and 0.085g of HCl were mixed and aged at -95℃ for 30 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 7.0 hours. Finally, 50g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0116] Comparative Example 1

[0117] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0118] Preparation of macromolecular brominating agents: Same as in Example 1.

[0119] Preparation of the five-membered three-heteroarm brominated grafting agent: Other conditions are the same as in Example 1, except that no macromolecular brominating agent is added during the preparation of the five-membered three-heteroarm brominated grafting agent. Instead, bromovinylbenzene is added. Specifically: First, in a 15L stainless steel reactor A with a jacket, argon gas is purged twice. Then, 1000g of cyclohexane, 300g of isoprene, and 1.0g of THF are added sequentially to the reactor. The temperature is raised to 60°C, and 14.5 mmol of n-butyllithium is added to initiate the reaction for 30 minutes. Subsequently, 400g of p-bromomethylstyrene is added to reactor A, and the reaction is continued for 90 minutes until no free monomers are present. Simultaneously, in a 15L stainless steel reactor B, argon gas is purged twice to purge the system. Then, 1000g of cyclohexane, 100g of styrene, and 200g of... 1,3-Butadiene, 2.0 g THF, heated to 60 °C, 30.5 mmol n-butyllithium was added to initiate the reaction for 60 min. Then, 200 g isoprene was added to reactor B, and the reaction was continued for 30 min to form the -IR-SBR- segment. Finally, 600 g p-bromomethylstyrene and 300 g bromovinylbenzene were added sequentially to reactor B, and the reaction was continued for 120 min until no free monomer remained. Simultaneously, in a 15 L stainless steel reactor C, the system was purged twice with argon gas, and 1000 g cyclohexane, 300 g 1,3-butadiene, and 1.0 g... THF was heated to 40°C, and 16.5 mmol of n-butyllithium was added to initiate a reaction for 50 min, forming -BR- segments. Then, 500 g of bromovinylbenzene was added to reactor C, and the reaction was continued for 70 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, and the temperature was raised to 80°C. 65.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 100 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain the five-membered three-hetero-arm brominated grafting agent-1 (Mn = 72000, Mw / Mn = 10.23).

[0120] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 1, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-1 is added, with an addition amount of 25.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 150g of dichloromethane, 350g of cyclohexane, and 25.0g of pentagonal tri-heteroarm brominated grafting agent-1 are added to the reactor. The mixture is stirred and dissolved for 60min until it is completely dissolved. Then, when the temperature is lowered to -80℃, 500g of dichloromethane, 450g of isobutylene, and 30.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -90℃. Then, 50g of dichloromethane, 1.23g of sesquiethylaluminum chloride, and HCl are added. 0.015g of the mixture was aged at -85℃ for 20 minutes, then added to the polymerization system and stirred for 5.0 hours. Finally, 25g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0121] Comparative Example 2

[0122] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0123] Preparation of macromolecular brominating agents: Same as in Example 2.

[0124] Preparation of the pentagonal tri-arm brominated grafting agent: Other conditions were the same as in Example 2, except that p-bromomethylstyrene was not added during the polymerization process in reactor A. Specifically, in a 15L stainless steel reactor A with a jacket, argon gas was purged twice, and 1200g cyclohexane, 310g isoprene, and 1.5g THF were added sequentially. The temperature was raised to 62°C, and 18.3 mmol of n-butyllithium was added to initiate the reaction for 32 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged twice, and 1200g cyclohexane, 120g styrene, and 220g... 1,3-Butadiene, 3.0 g THF, heated to 62 °C, 35.6 mmol n-butyllithium was added to initiate a reaction for 64 min. Then, 220 g isoprene was added to reactor B, and the reaction proceeded for 32 min to form the -IR-SBR- segment. Finally, 620 g p-bromomethylstyrene and 330 g macromolecular brominating agent were added sequentially to reactor B, and the reaction proceeded for 126 min until no free monomer remained. Simultaneously, in a 15 L stainless steel reactor C, the system was purged twice with argon gas, and 1200 g cyclohexane, 310 g 1,3-butadiene, and 1.5 g... THF was heated to 42°C, and 19.5 mmol of n-butyllithium was added to initiate a reaction for 52 min, forming -BR- segments. Then, 550 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 73 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, and the temperature was raised to 82°C. 100.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 105 min, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain the five-membered three-hetero-arm brominated grafting agent-2 (Mn = 82000, Mw / Mn = 11.35).

[0125] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 2, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-2 is added, with an addition amount of 22.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 200g of dichloromethane, 300g of cyclohexane, and 22.0g of pentagonal tri-heteroarm brominated grafting agent-2 are added to the reactor. The mixture is stirred and dissolved for 63min until completely dissolved. Then, when the temperature is lowered to -82℃, 600g of dichloromethane, 445g of isobutylene, and 33.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -92℃. Then, 60g of dichloromethane, 1.41g of sesquiethylaluminum chloride, and HCl are added. 0.032g of the mixture was aged at -87℃ for 23 minutes, then added to the polymerization system and stirred for 5.5 hours. Finally, 30g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0126] Comparative Example 3

[0127] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0128] Preparation of macromolecular brominating agents: Same as in Example 3.

[0129] Preparation of the pentagonal tri-arm brominated grafting agent: Other conditions were the same as in Example 3, except that the amount of macromolecular brominated agent added during the polymerization process in reactor C was 100g. Specifically: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged three times, and 1400g of cyclohexane, 330g of isoprene, and 2.0g of THF were added sequentially. The temperature was raised to 64°C, and 20.6 mmol of n-butyllithium was added to start the reaction for 34 min. Then, 360g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 80 min until no free monomers were present. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged three times, and 1400g of cyclohexane, 140g of styrene, 240g of 1,3-butadiene, and 3.5g of... THF was heated to 64°C, and 40.6 mmol of n-butyllithium was added to initiate a reaction for 68 min. Then, 240 g of isoprene was added to reactor B, and the reaction proceeded for 34 min to form the -IR-SBR- segment. Finally, 640 g of p-bromomethylstyrene and 380 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction proceeded for 130 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged three times with argon gas, and 1400 g of cyclohexane, 330 g of 1,3-butadiene, and 2.0 g of... THF was heated to 44°C, and 26.5 mmol of n-butyllithium was added to initiate a reaction for 54 min, forming -BR- segments. Then, 100 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 78 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, and the temperature was raised to 84°C. 170.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 110 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain the five-membered three-hetero-arm brominated grafting agent-3 (Mn is 87000, Mw / Mn is 11.87).

[0130] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 3, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-3 is added, with an addition amount of 26.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 300g of dichloromethane, 200g of cyclohexane, and 26.0g of pentagonal tri-heteroarm brominated grafting agent-3 are added to the reactor. The mixture is stirred and dissolved for 66min until it is completely dissolved. Then, when the temperature is lowered to -85℃, 700g of dichloromethane, 440g of isobutylene, and 34.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -95℃. Then, 70g of dichloromethane, 1.65g of sesquiethylaluminum chloride, and HCl are added. 0.047g of the mixture was aged at -90℃ for 26 minutes and then added to the polymerization system. After stirring for 6.0 hours, 35g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0131] Comparative Example 4

[0132] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0133] Preparation of macromolecular brominating agents: Same as in Example 4.

[0134] Preparation of the pentagonal trihexy-arm brominated grafting agent: Other conditions were the same as in Example 4, except that a two-reactor polymerization was used, without the reaction in reactor B. Specifically: First, in a 15L stainless steel reactor A with a jacket, argon gas was purged three times, and 1600g of cyclohexane, 350g of isoprene, and 3.0g of THF were added sequentially. The temperature was raised to 66°C, and 26.6 mmol of n-butyllithium was added to initiate the reaction for 36 min. Then, 340g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 77 min until no free monomers were present. Simultaneously, in a 15L stainless steel reactor C, argon gas was purged three times, and 1600g of cyclohexane, 350g of 1,3-butadiene, and 2.4g of... THF was heated to 46°C, and 30.5 mmol of n-butyllithium was added to initiate a reaction for 56 min, forming the -BR- segment. Then, 630 g of macromolecular brominating agent was added to reactor C, and the reaction was continued for 80 min until no free monomers were present. Finally, the material from reactor C was added to reactor A, heated to 85°C, and 220.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 115 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain the five-membered three-hetero-arm brominated grafting agent-4 (Mn is 62000, Mw / Mn is 6.25).

[0135] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 4, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-4 is added, with an addition amount of 28.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 700g of dichloromethane, 300g of cyclohexane, and 28.0g of pentagonal tri-heteroarm brominated grafting agent-4 are added to the reactor. The mixture is stirred and dissolved for 70min until it is completely dissolved. Then, when the temperature is lowered to -87℃, 800g of dichloromethane, 435g of isobutylene, and 37.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -96℃. Then, 80g of dichloromethane, 1.82g of sesquiethylaluminum chloride, and HCl are added. 0.058g of the mixture was aged at -92℃ for 28 minutes, then added to the polymerization system and stirred for 6.3 hours. Finally, 40g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0136] Comparative Example 5

[0137] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0138] Preparation of macromolecular brominating agents: Same as in Example 5.

[0139] Preparation of the pentagonal tri-hetero-arm brominated grafting agent: Other conditions were the same as in Example 5, except that tert-butyltrichlorosilane was not added for coupling during the preparation of the pentagonal tri-hetero-arm brominated grafting agent. Specifically: First, in a jacketed 15L stainless steel reactor A, argon gas was purged four times. Then, 1800g of cyclohexane, 370g of isoprene, and 3.5g of THF were added sequentially. The temperature was raised to 68°C, and 30.6 mmol of n-butyllithium was added to initiate the reaction for 38 minutes. Subsequently, 320g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 74 minutes until no free monomer remained. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged four times. Then, 1800g of cyclohexane, 180g of styrene, 290g of 1,3-butadiene, and 4.5g of... THF was heated to 68°C, and 50.6 mmol of n-butyllithium was added to initiate a reaction for 75 min. Then, 280 g of isoprene was added to reactor B, and the reaction continued for 38 min to form the -IR-SBR- segment. Finally, 680 g of p-bromomethylstyrene and 460 g of macromolecular brominating agent were added sequentially to reactor B, and the reaction continued for 137 min until no free monomers remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged four times with argon gas, and 1800 g of cyclohexane, 370 g of 1,3-butadiene, and 2.7 g of THF were added sequentially. The temperature was raised to 48°C, and 35.5 mmol of n-butyllithium was added to initiate a reaction for 58 min to form the -BR- segment. Then, 660 g of macromolecular brominating agent was added to reactor C, and the reaction continued for 85 min until no free monomers remained. Finally, the gel was wet-coagulated and dried to obtain the five-membered three-hetero-arm brominated grafting agent-5. (Mn is 86000, Mw / Mn is 4.29).

[0140] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 5, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-5 is added, with an addition amount of 31.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 600g of dichloromethane, 400g of cyclohexane, and 31.0g of pentagonal tri-heteroarm brominated grafting agent-5 are added to the reactor. The mixture is stirred and dissolved for 76 minutes until it is completely dissolved. Then, when the temperature is lowered to -88℃, 900g of dichloromethane, 430g of isobutylene, and 39.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -98℃. Then, 90g of dichloromethane, 1.95g of sesquiethylaluminum chloride, and HCl are added. 0.067g of the mixture was aged at -93℃ for 29 min, then added to the polymerization system and stirred for 6.6 hr. Finally, 45g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0141] Comparative Example 6

[0142] (1) Preparation of pentagonal trihexyarm brominated grafting agent:

[0143] Preparation of macromolecular brominating agent: Other conditions are the same as in Example 6, except that 1,3-butadiene is not added for end-capping reaction during the preparation of macromolecular brominating agent. That is: first, nitrogen gas is purged into a 15L stainless steel reactor with a jacket four times, and 3000g of cyclohexane, 1000g of bromovinylbenzene, and 5.0g of tert-dodecyl mercaptan are added to the reactor in sequence. The mixture is stirred and heated. When the reactor temperature reaches 90°C, 4.0g of BPO is added and the reaction is carried out for 5.0 hours until no free monomers are present. After the reaction is completed, the mixture is washed and dried to obtain macromolecular brominating agent-1.

[0144] Preparation of the pentagonal tri-heteroarm brominated grafting agent: Other conditions were the same as in Example 6, except that no macromolecular brominizing agent was added during the preparation of the pentagonal tri-heteroarm brominated grafting agent. Instead, macromolecular brominizing agent-1 was added. Specifically, in a 15L stainless steel reactor A with a jacket, argon gas was purged four times. Then, 2000g of cyclohexane, 400g of isoprene, and 4.0g of THF were added sequentially to the reactor. The temperature was raised to 70°C, and 40.6 mmol of n-butyllithium was added to initiate the reaction for 40 minutes. Subsequently, 300g of p-bromomethylstyrene was added to reactor A, and the reaction was continued for 70 minutes until no free monomers were present. Simultaneously, in a 15L stainless steel reactor B, argon gas was purged four times. Then, 2000g of cyclohexane, 200g of styrene, 300g of 1,3-butadiene, and 5.0g of... THF was heated to 70°C, and 60.6 mmol of n-butyllithium was added to initiate a reaction for 80 min. Then, 300 g of isoprene was added to reactor B, and the reaction proceeded for 40 min to form the -IR-SBR- segment. Finally, 700 g of p-bromomethylstyrene and 500 g of macromolecular brominating agent-1 were added sequentially to reactor B, and the reaction proceeded for 140 min until no free monomer remained. Simultaneously, in a 15L stainless steel reactor C, the system was purged four times with argon gas, and 2000 g of cyclohexane, 400 g of 1,3-butadiene, and 3.0 g of... THF was heated to 50°C, and 40.5 mmol of n-butyllithium was added to initiate a reaction for 60 min, forming the -BR- segment. Then, 700 g of macromolecular brominating agent-1 was added to reactor C, and the reaction was continued for 90 min until no free monomers were present. Finally, the materials from reactors B and C were added to reactor A, heated to 90°C, and 400.5 mmol of tert-butyltrichlorosilane was added to initiate a coupling reaction. After reacting for 130 min, the coupled reaction mixture was treated with water, and the gel was wet-coagulated and dried to obtain the five-membered three-hetero-arm bromination grafting agent-6 (Mn is 81000, Mw / Mn is 10.57).

[0145] (2) Preparation of highly branched tri-heteroarm brominated butyl rubber: Other conditions are the same as in Example 6, except that: no pentagonal tri-heteroarm brominated grafting agent is added during the preparation of highly branched tri-heteroarm brominated butyl rubber, but pentagonal tri-heteroarm brominated grafting agent-6 is added, with an addition amount of 35.0g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 300g of dichloromethane, 700g of cyclohexane, and 35.0g of pentagonal tri-heteroarm brominated grafting agent-6 are added to the reactor. The mixture is stirred and dissolved for 80min until it is completely dissolved. Then, when the temperature is lowered to -90℃, 1000g of dichloromethane, 425g of isobutylene, and 40.0g of isoprene are added in sequence. The mixture is stirred and mixed until the polymerization system temperature drops to -100℃. Then, 100g of dichloromethane, 2.05g of sesquiethylaluminum chloride, and HCl are added. 0.085g of the mixture was aged at -95℃ for 30 minutes, then added to the polymerization system and stirred for 7.0 hours. Finally, 50g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated highly branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0146] Table 1 Properties of Highly Branched Tri-Hybrid Brominated Butyl Rubber

[0147]

[0148]

[0149] Note: t 10 The scorching time reflects the size of the scorching safety window; t 90 The positive vulcanization time reflects the speed of vulcanization.

[0150] As shown in Table 1, the highly branched tri-arm brominated butyl rubber of the present invention has a high degree of branching, a high vulcanization rate and a short Mooney stress relaxation time, exhibiting good processing and vulcanization characteristics, while maintaining high tensile strength and good air tightness.

[0151] The above embodiments are typical examples listed to illustrate the technical solution of the present invention in detail. The present invention shall be subject to the protection scope of the claims and the invention content, and shall not be limited by the described embodiments. Simple substitutions or modifications to the present invention shall still be within the protection scope of the present invention.

Claims

1. A method for preparing highly branched tri-heteroarm brominated butyl rubber, the method comprising the following steps: S1: Add the pentagonal tri-arm brominated grafting agent to the mixed solvent and stir thoroughly until the pentagonal tri-arm brominated grafting agent is completely dissolved to obtain a mixed solution; S2: Cool down, add diluent, isobutylene and isoprene to the mixed solution in step S1 in sequence, stir and mix thoroughly to obtain the polymerization reaction system, and cool down again; S3: Mix the diluent and co-initiator and age them. Then add them to the polymerization reaction system of step S2 and stir the reaction thoroughly. Add the terminator, discharge the material, coagulate, wash and dry to obtain highly branched tri-heteroarm brominated butyl rubber. The method for preparing the five-membered three-heterotrophic arm brominated grafting agent is characterized by the following steps: Preparation of macromolecular brominating agent: Taking 100 parts by mass of reactive brominating agent, firstly, add 200-300 parts of solvent, 100 parts of bromovinylbenzene, and 0.2-0.5 parts of molecular weight regulator sequentially to the reaction vessel after inert gas replacement. Stir and mix, heat, and when the reaction vessel temperature reaches 70-90℃, add 0.05-0.5 parts of the first initiator. React for 3.0-5.0 hours, at which point the conversion rate of bromovinylbenzene reaches 100%. Then, add 1-5 parts of 1,3-butadiene to the reaction vessel for end-capping, and react for 40-60 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain macromolecular brominating agent. Preparation of the five-membered three-hetero-arm brominated grafting agent: Based on 100% of the mass of the reactive brominating agent, first add 100wt%~200wt% solvent, 30wt%~40wt% isoprene, 0.1wt%~0.4wt% structure modifier, and second initiator sequentially to reactor A after inert gas replacement. Heat to 60~70℃ and react for 30~40min. Then add 30wt%~40wt% reactive brominating agent to reactor A and react for 70~90min until no free monomers are present. Simultaneously, 100 wt%~200 wt% solvent, 10 wt%~20 wt% styrene, 20 wt%~30 wt% 1,3-butadiene, 0.2 wt%~0.5 wt% structure modifier, and a second initiator are added sequentially to reactor B after inert gas purging. The temperature is raised to 60~70℃, and the reaction is carried out for 60~80 min. Then, 20 wt%~30 wt% isoprene is added to reactor B, and the reaction is carried out for 30~40 min to form -IR-SBR- segments. Finally, 60 wt%~70 wt% reactive brominating agent and 30 wt%~50 wt% macromolecular brominating agent are added sequentially to reactor B, and the reaction is carried out for 120~140 min until no free monomers are present. Simultaneously, 100 wt%~200 wt% solvent, 30 wt%~40 wt% 1,3-butadiene, 0.1 wt%~0.3 wt% structure modifier, and a second initiator are added sequentially to reactor C after inert gas purging. The temperature is raised to 40~50℃, and the reaction is carried out for 50~60 min to form -BR- segments. Then, 50 wt%~70 wt% macromolecular brominating agent is added to reactor C, and the reaction is carried out for 70~90 min until no free monomers are present. Finally, the materials in reactors B and C are added to reactor A, the temperature is raised to 80-90℃, a coupling agent is added to carry out the coupling reaction, and after reacting for 100-130 minutes, the coupled reaction mixture is treated with water, and then wet coagulation and drying are performed to obtain the five-membered three-hetero-arm brominated grafting agent. The reactive brominating agent is p-bromomethylstyrene; The number-average molecular weight (Mn) of the pentagonal trihexyarm brominated grafting agent is 90,000 to 110,000, and the molecular weight distribution (Mw / Mn) is 14.15 to 15.

62.

2. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, In step S1, the mass ratio of the mixed solvent to the pentagonal trihexyarm brominated grafting agent is 100~200:4~7; the mixed solvent includes a diluent and a solvent, and the volume ratio of the diluent to the solvent is 70~30 / 30~70.

3. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, In step S2, the temperature is cooled to -80~-90℃, and the temperature is cooled again to -100~-90℃.

4. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, In step S2, the mass ratio of the diluent, isobutylene, and isoprene is 100~200:85~90:6~8.

5. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, In step S3, the mass ratio of the diluent, co-initiator, and terminator is 10~20:0.1~0.5:5~10.

6. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, The molecular weight regulator is selected from at least one of tert-decanethiol, tert-dodecanethiol, tert-tetradecanethiol, and tert-hexadecanethiol; The first initiator is an organic peroxide, selected from at least one of dicumyl peroxide, cumyl hydroperoxide, benzoyl peroxide (BPO), and di-tert-butyl peroxide. The structure modifier is a polar organic compound selected from at least one of diethylene glycol dimethyl ether 2G, tetrahydrofuran THF, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether DME, and triethylamine. The second initiator is a hydrocarbon-based monolithium compound RLi, selected from at least one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium.

7. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 6, characterized in that, The molecular weight regulator is tert-dodecyl mercaptan.

8. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 6, characterized in that, The first initiator is benzoyl peroxide (BPO).

9. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 6, characterized in that, The structure modifier is tetrahydrofuran (THF).

10. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 6, characterized in that, The second initiator is n-butyllithium.

11. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, The coupling agent is a halosilane selected from at least one of tert-butyltrichlorosilane and tert-butyltribromosilane; the molar ratio of the coupling agent to the second initiator is 1:1 to 5:

1.

12. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 11, characterized in that, The coupling agent is tert-butyltrichlorosilane.

13. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1 or 2, characterized in that, The solvent is selected from one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene.

14. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 13, characterized in that, The solvent is cyclohexane.

15. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, The diluent is a haloalkane, selected from at least one of chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, and fluorobutane.

16. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 15, characterized in that, The diluent is dichloromethane.

17. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, The co-initiator is composed of an alkyl aluminum halide and a protic acid in a specific ratio; the alkyl aluminum halide is selected from at least one of diethylaluminum chloride, diisobutylaluminum chloride, dichloromethylaluminum, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, dichloro-n-propylaluminum, dichloroisopropylaluminum, dimethylaluminum chloride, and ethylaluminum chloride; the protic acid is selected from one of HCl, HF, HBr, H2SO4, H3PO4, and HNO3; the molar ratio of the protic acid to the alkyl aluminum halide is 0.05:1 to 0.2:

1.

18. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 17, characterized in that, The alkyl aluminum halide is sesquiethyl aluminum chloride.

19. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 17, characterized in that, The protic acid is HCl.

20. The method for preparing highly branched tri-heteroarm brominated butyl rubber according to claim 1, characterized in that, The terminating agent is at least one of methanol, ethanol, and butanol.

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