A method for preparing a wide distribution brominated branched butyl rubber

Abstract

The application discloses a preparation method of wide-distribution brominated branched butyl rubber, and the preparation method comprises the following steps: adding a high-molecular three-arm wide-distribution brominated grafting agent into a mixed solvent, fully stirring until the high-molecular three-arm wide-distribution brominated grafting agent is completely dissolved, and obtaining a mixed solution; cooling, adding a diluent, isobutene and isoprene into the mixed solution in sequence, fully stirring and mixing, obtaining a polymerization reaction system, and cooling again; mixing and aging the diluent and a co-initiator, then adding the diluent and the co-initiator into the polymerization reaction system, fully stirring and reacting, adding a terminating agent, and discharging, coagulating, washing and drying, so as to obtain the wide-distribution brominated branched butyl rubber; the high-molecular three-arm wide-distribution brominated grafting agent is a three-arm wide-distribution brominated star block copolymer which is composed of isoprene and a macromolecular complex brominated agent. The preparation method of the 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 a broadly distributed brominated branched butyl rubber, specifically a method for preparing a broadly distributed brominated branched butyl rubber by grafting a primary and secondary brominated isoprene / butadiene / styrene three-arm block copolymer. 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 increased the 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 present invention aims to provide a method for preparing a broadly distributed brominated branched butyl rubber. This method uses a macromolecular composite brominator as a raw material, which exhibits anionic reactivity. Next, a polymeric broadly distributed three-arm brominated grafting agent with a broad distribution, three-arm structure, and primary and secondary bromine structures is prepared from the reactants isoprene, styrene, butadiene, the macromolecular composite brominator, and a coupling agent. Finally, using the polymeric broadly distributed three-arm brominated grafting agent, isobutylene, and isoprene as reactants, a method for preparing the broadly distributed brominated branched butyl rubber via cationic polymerization is used. This method prepares butyl rubber with both primary and secondary bromine structures through addition polymerization, avoiding bromine structure rearrangement in brominated butyl rubber and solving the problem of bromine structure stability in brominated branched butyl rubber. This not only greatly improves the vulcanization speed of butyl rubber but also ensures scorch safety during the vulcanization process. At the same time, a wide molecular weight distribution of butyl rubber was achieved, which not only solved the problem of slow stress relaxation rate of butyl rubber during processing, but also maintained sufficient raw rubber strength and good air tightness of butyl rubber, achieving a balance between the physical and mechanical properties and processing performance of 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 a broadly distributed brominated branched butyl rubber, the method comprising the following steps:

[0015] S1: Add the polymeric three-arm wide-distribution brominated grafting agent to the mixed solvent and stir thoroughly until the polymeric three-arm wide-distribution 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 a broadly distributed brominated branched butyl rubber.

[0018] The feature is that the polymeric three-arm wide-distribution brominated grafting agent is a three-arm wide-distribution brominated star-shaped block copolymer composed of isoprene and a macromolecular composite brominated agent, and its general structural formula is shown in Formula I:

[0019]

[0020] Wherein, IR represents isoprene homopolymer block; the macromolecular composite brominating agent is a random block copolymer of bromovinylbenzene, cis-2-methyl-1,4-dibromo-2-butene, and 1,3-butadiene; m and n are the number of repeating units, where m is an integer ≥1 and n is an integer ≥1; the number average molecular weight (Mn) of the polymeric three-arm wide-distribution brominated grafting agent is 50,000 to 70,000, and the molecular weight distribution (Mw / Mn) is 6.17 to 8.34.

[0021] In the preparation method of the broadly distributed brominated branched butyl rubber of the present invention, in step S1, the mass ratio of the mixed solvent and the polymeric three-arm broadly distributed brominated grafting agent is 100-200:3-6.

[0022] In the preparation method of the broadly distributed brominated branched 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 80-20 / 20-80.

[0023] In the preparation method of the broadly distributed brominated branched 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 broadly distributed brominated branched butyl rubber of the present invention, in step S2, the mass ratio of the diluent, isobutylene and isoprene is 100-200:90-95:2-4.

[0025] In the preparation method of the broadly distributed brominated branched 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 broadly distributed brominated branched butyl rubber of the present invention, in step S3, the mass ratio of the diluent, co-initiator and terminator is 20-30: 0.1-0.5: 5-10.

[0027] In the preparation method of the wide-distribution brominated branched butyl rubber of the present invention, in step S3, the aging temperature is -95℃ to -85℃ and the aging time is 40 to 60 min.

[0028] The preparation method of the broadly distributed brominated branched butyl rubber of the present invention specifically includes the following steps:

[0029] Preparation of a macromolecular composite brominating agent: Taking 100 parts by mass of reactive brominating agent, firstly, add 200-300 parts of solvent, 90-95 parts of bromovinylbenzene, 5-10 parts of cis-2-methyl-1,4-dibromo-2-butene, and 0.2-0.5 parts of molecular weight regulator to a reaction vessel after inert gas replacement. Stir and mix, heat, and when the reaction vessel temperature reaches 60-80℃, add 0.1-0.4 parts of the first initiator. React for 4.0-6.0 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 30-50 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain the macromolecular composite brominating agent.

[0030] b. Preparation of a polymeric three-arm broad-distribution brominated grafting agent: Based on 100% of the total mass of the reactants, first, 100wt%–200wt% solvent, 30wt%–40wt% isoprene, 0.2wt%–0.5wt% structure modifier, and a second initiator are added sequentially to a reactor after inert gas purging. The reaction is a temperature-variable polymerization, with a reaction time of 40–60 min, and the temperature is gradually increased from 50℃ to 70℃ to form broadly distributed IR segments. Next, 100wt%–200wt% solvent and 60wt%–70wt% macromolecular composite brominizing agent are added sequentially to the reactor, and the temperature is raised to 70–80℃, reacting for 80–100 min until no free monomers are present. Finally, the temperature is raised to 80℃–90℃, and a coupling agent is added to carry out a coupling reaction for 60–80 min. After the reaction is completed, the coupled reaction mixture is treated with water, followed by wet coagulation and drying to obtain the polymeric three-arm broad-distribution brominated grafting agent.

[0031] The method for preparing the broadly distributed brominated branched 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.

[0032] The method for preparing the broadly distributed brominated branched butyl rubber of the present invention, wherein the first initiator is an organic peroxide selected from at least one of 1,1-dimethylethyl hydroperoxide (TB), tert-butyl hydroperoxide (TBHP), di-tert-butyl hydroperoxide and tert-pentyl hydroperoxide (TAHP), preferably tert-butyl hydroperoxide (TBHP).

[0033] The present invention discloses a method for preparing a broadly distributed brominated branched butyl rubber, wherein the structure regulator is a polar organic compound that produces a solvation effect in the polymerization system, thereby adjusting the reactivity ratio between styrene and isoprene and enabling random copolymerization of the two. 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).

[0034] In the preparation method of the broadly distributed brominated branched 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.

[0035] The method for preparing the broadly distributed brominated branched butyl rubber of the present invention includes a coupling agent that is at least one selected from 1,3,5-trichlorobenzene and 1,3,5-tribromobenzene, preferably 1,3,5-trichlorobenzene. 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.

[0036] In the preparation method of the broadly distributed brominated branched butyl rubber of the present invention, the polymerization reactions are 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 at least one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene, with hexane being preferred.

[0037] The present invention discloses a method for preparing a broadly distributed brominated branched butyl rubber, wherein the diluent 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. The haloalkane is selected from at least one of chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane, preferably chloromethane.

[0038] The present invention discloses a method for preparing a broadly distributed brominated branched butyl rubber, wherein the co-initiator is composed of an alkyl aluminum halide and a protic acid 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 at least 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 0.5:1.

[0039] The method for preparing the broadly distributed brominated branched butyl rubber of the present invention includes a terminating agent, for example but not limited to, at least one of methanol, ethanol, and butanol.

[0040] The present invention can also be described in detail below:

[0041] In detail, the specific preparation process of the broadly distributed brominated branched butyl rubber of the present invention includes the following steps:

[0042] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0043] Preparation of a macromolecular composite 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, 90-95 parts of bromovinylbenzene, 5-10 parts of cis-2-methyl-1,4-dibromo-2-butene, 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 60-80℃, add 0.1-0.4 parts of the first initiator. React for 4.0-6.0 hours, at which point the conversion rate of bromovinylbenzene reaches 100%. Then, add 1-5 parts of 1,3-butadiene to the reactor for end-capping, and react for 30-50 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain the macromolecular composite brominating agent.

[0044] Preparation of a broad-distribution brominated grafting agent with three arms: Based on 100% of the total mass of the reactants, first, in a jacketed 15L stainless steel reactor, purge with argon gas 2-4 times. Then, sequentially add 100wt%-200wt% solvent, 30wt%-40wt% isoprene, 0.2wt%-0.5wt% structure modifier, and a second initiator. The reaction is a temperature-variable polymerization, with a reaction time of 40-60 min and the temperature gradually increased from 50℃ to 70℃, forming a broad-distribution I... R-segment; then, 100wt%–200wt% solvent and 60wt%–70wt% macromolecular composite brominating agent are added sequentially to the reactor, the temperature is raised to 70–80℃, and the reaction is carried out for 80–100 min until no free monomers are present; finally, the temperature is raised to 80℃–90℃, and a coupling agent is added to carry out a coupling reaction for 60–80 min. After the reaction is completed, the coupled reaction mixture is treated with water, and the gel is wet coagulated and dried to obtain a high molecular weight three-arm broad-distribution brominated grafting agent.

[0045] (2) Preparation of broadly distributed brominated branched 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 80-20 / 20-80), 3wt%-6wt% of a three-arm broadly distributed brominated grafting agent, and stir to dissolve for 80-90 minutes until the grafting agent is completely dissolved; then, when the temperature is lowered to -80 to -90℃, add 100wt%-200wt% diluent, 90wt%-95wt% isobutylene, and 2wt%-4wt% isoprene in sequence, stirring and mixing until the polymerization system temperature drops to -100 to -90℃, then add 20wt%-6wt% of the diluent. 30% diluent and 0.1wt% to 0.5wt% co-initiator are mixed and aged at -95 to -85°C for 40 to 60 minutes, then added together to the polymerization system and stirred for 4.0 to 6.0 hours. Finally, 5wt% to 10wt% terminator is added, the mixture is discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product.

[0046] The polymeric three-arm wide-distribution brominated grafting agent of the present invention is a three-arm wide-distribution brominated star-shaped block copolymer composed of isoprene and a macromolecular composite brominated agent, and its general structural formula is shown in Formula I:

[0047]

[0048] Wherein, IR represents isoprene homopolymer block; the macromolecular composite brominating agent is a random block copolymer of bromovinylbenzene, cis-2-methyl-1,4-dibromo-2-butene, and 1,3-butadiene; m and n are the number of repeating units. The number-average molecular weight (Mn) of the high-molecular-weight three-arm wide-distribution brominated grafting agent is 50,000–70,000, and the molecular weight distribution (Mw / Mn) is 6.17–8.34.

[0049] The preparation process of the polymeric three-arm broad-distribution brominated grafting agent of the present invention involves free radical polymerization of cis-2-methyl-1,4-dibromo-2-butene and bromovinylbenzene to generate a macromolecular composite brominated agent, followed by end-capping activation with 1,3-butadiene to prepare a macromolecular composite brominated agent with anionic reactivity, and then preparing a polymeric three-arm broad-distribution brominated grafting agent with a three-arm structure, broad distribution, and primary and secondary bromine structures by reacting monomer isoprene, macromolecular composite brominated agent and coupling agent.

[0050] The polymeric three-arm broad-distribution brominated grafting agent of the present invention mainly plays three roles:

[0051] On the one hand, this polymeric three-arm wide-distribution brominated grafting agent uses free radical polymerization and anionic polymerization, rather than the ionic substitution reaction in existing technologies, thus avoiding the generation of the byproduct HBr and blocking the isomerization conditions of the bromine structure. This inhibits the molecular rearrangement of secondary bromine in brominated branched butyl rubber to form berberine bromine, improves the stability of the secondary bromine structure in brominated branched butyl rubber, greatly increases the vulcanization speed of butyl rubber, and ensures that the scorch time is within a reasonable range, thus ensuring vulcanization efficiency and the quality of the vulcanized rubber.

[0052] Secondly, this polymeric three-arm wide-distribution brominated grafting agent improves the utilization rate of bromine. The polymeric brominated grafting agent uses an organic brominated agent containing unsaturated double bonds to first undergo free radical polymerization to generate a macromolecular brominated agent, which then participates in the anionic reaction. No HBr is generated during the entire reaction process, avoiding the loss of other bromine, increasing the degree of reaction of the organic brominated agent, improving the utilization rate of bromine in brominated branched butyl rubber, and at the same time eliminating the need for alkaline washing and recovery of the by-product HBr, thereby shortening the process and reducing production costs.

[0053] In three aspects, this polymeric three-arm wide-distribution brominated grafting agent is produced by temperature-variable polymerization, where the polymerization temperature is continuously changed. This results in a wide-distribution IR segment that improves the flexibility of butyl rubber segments, significantly broadens its molecular weight distribution, and achieves a fast stress relaxation rate, thus enabling it to obtain good viscoelastic properties. Simultaneously, its three-arm star-shaped branched structure disrupts the regularity of butyl rubber segments, further broadening the molecular weight distribution and resulting in excellent processing performance. Furthermore, the macromolecular composite brominated agent segments contain a large number of benzene rings, preventing a decrease in strength and airtightness due to the broadened molecular weight distribution of butyl rubber, ensuring that butyl rubber possesses high strength and good airtightness.

[0054] Therefore, the polymeric three-arm wide-distribution brominated grafting agent of the present invention organically combines the primary bromine structure, secondary bromine structure, three-arm star structure and wide-distribution IR segments and works synergistically to solve the contradiction between the poor processability and good physical properties of butyl rubber, and achieves a balance between the vulcanization characteristics, processability, strength and air tightness of butyl rubber, so that the performance of butyl rubber is more comprehensively improved.

[0055] In summary, the present invention has the following beneficial effects:

[0056] 1. The polymeric three-arm wide-distribution brominated grafting agent of the present invention contains secondary and primary bromine structures generated by addition polymerization, rather than by ionic substitution as in the prior art. This avoids the generation of the byproduct hydrogen bromide (HBr), blocks the conditions for isomerization of the secondary bromine structure to the primary structure, thereby greatly inhibiting the rearrangement of the bromine structure, improving the stability of the secondary bromine structure in brominated branched butyl rubber, greatly increasing the vulcanization speed of butyl rubber, and ensuring that the scorch time is within a reasonable range, thus ensuring vulcanization efficiency and the quality of the vulcanized rubber.

[0057] 2. The polymeric three-arm wide-distribution brominated grafting agent of the present invention first undergoes free radical polymerization of an organic brominated agent containing unsaturated double bonds to generate a macromolecular brominated agent, which then participates in anionic reactions. During the entire reaction process, HBr is not generated, thus avoiding the loss of other bromine, increasing the degree of reaction of the organic brominated agent, and improving the utilization rate of bromine in brominated branched butyl rubber.

[0058] 3. The polymeric three-arm wide-distribution brominated grafting agent of the present invention does not generate the byproduct HBr during the entire reaction process, reducing the harm to humans and the environment, eliminating the need for alkaline washing and recovery of the byproduct HBr, thereby shortening the process flow and reducing production costs.

[0059] 4. The polymeric three-arm wide-distribution brominated grafting agent of the present invention contains widely distributed vinyl segments, a three-arm star-shaped branched structure, and a benzene ring structure. This chain structure can increase the disorder of butyl rubber molecular chain segments, broaden the molecular weight distribution of butyl rubber, obtain excellent processing performance, and ensure that butyl rubber has high strength and good air tightness, thus achieving a balance between the vulcanization characteristics, processability, strength, and air tightness of butyl rubber.

[0060] 5. The polymeric three-arm wide-distribution brominated grafting agent of the present invention is a novel safe and environmentally friendly compound with no emissions of air pollutants (VOCs) and byproduct HBr. Its preparation method is green and environmentally friendly, with a short process flow, stable bromine structure, excellent processing performance, and is suitable for industrial production. Detailed Implementation

[0061] 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.

[0062] (1) Source of raw materials:

[0063] Styrene, 1,3-butadiene, polymer grade, China National Petroleum Corporation Lanzhou Petrochemical Company;

[0064] Isobutylene and isoprene, polymer grade, Zhejiang Xinhui New Materials Co., Ltd.

[0065] cis-2-methyl-1,4-dibromo-2-butene, polymer grade, Shanghai Yishi Chemical Co., Ltd.

[0066] Bromovinylbenzene, Polymerization Grade, Shanghai Yishi Chemical Co., Ltd.

[0067] tert-butyl hydroperoxide (TBHP), Lanzhou Additives Factory;

[0068] n-Butyllithium, 98% purity, Nanjing Tonglian Chemical Co., Ltd.

[0069] 1,3,5-Trichlorobenzene, purity 99%, Yangzhou Haichen Chemical Co., Ltd.;

[0070] Sesquiethylaluminum chloride, 98% purity, Bailingwei Technology Co., Ltd.

[0071] All other reagents are commercially available industrial products.

[0072] (2) Analysis and testing methods:

[0073] 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:

[0074]

[0075] 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.

[0076] 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 .

[0077] 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 after the rotor stops was set as 100%, and the stress relaxation behavior of the rubber was expressed using t80 (the time it takes for 80% of the torque to decay (remaining 20%)) and X30 (the percentage of torque remaining 30 seconds after the rotor stops).

[0078] Vulcanization characteristics: tested according to GB / T 16584—1996.

[0079] Air tightness determination: An automated air tightness tester was used to determine the air permeability number according to ISO 2782:1995.

[0080] 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.

[0081] Tensile strength: The method specified in standard GB / T528-2009 shall be applied.

[0082] Example 1

[0083] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0084] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 2000g of pentane, 900g of bromovinylbenzene, 100g of cis-2-methyl-1,4-dibromo-2-butene, 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 60℃, 1.0g of TBHP was added, and the reaction was carried out for 4.0hr. Then, 10g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 30min until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular composite brominating agent.

[0085] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged twice. Then, 1000g of pentane, 400g of isoprene, and 2.0g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 22.3 mmol of n-butyllithium was added to initiate the reaction. The reaction temperature was gradually increased from 50°C to 70°C over a 40-minute reaction period at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1000 g of pentane and 600 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 70°C. The reaction was continued for 80 minutes until no free monomers were present. Finally, the temperature was raised to 80°C, and 30.7 mmol of 1,3,5-trichlorobenzene was added. The reaction was continued for 60 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 51000, Mw / Mn = 6.17).

[0086] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged three times. Then, 400g of chloromethane, 100g of cyclohexane, and 15.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 80 minutes until completely dissolved. Next, the temperature was lowered to -80℃, and then 500g of chloromethane, 475g of isobutylene, and 10g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -90℃. Then, 100g of chloromethane, 0.7g of sesquiethylaluminum chloride, and 0.012g of HCl were mixed and aged at -85℃ for 40 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.0 hours. Finally, 25g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0087] Example 2

[0088] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0089] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 2100g of pentane, 910g of bromovinylbenzene, 90g of cis-2-methyl-1,4-dibromo-2-butene, 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 63℃, 1.5g of TBHP was added, and the reaction was carried out for 4.3 hours. Then, 15g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 32 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular composite brominating agent.

[0090] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged twice. Then, 1100g of pentane, 390g of isoprene, and 2.5g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 24.9 mmol of n-butyllithium was added to initiate the reaction. During the 40-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1200 g of pentane and 610 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 72°C. The reaction was carried out for 83 minutes until no free monomers were present. Finally, the temperature was raised to 81°C, and 40.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 63 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 55000, Mw / Mn = 6.56).

[0091] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. Then, 300g of chloromethane, 200g of cyclohexane, and 17.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 82 minutes until completely dissolved. Then, the temperature was lowered to -81℃, and 600g of chloromethane, 471g of isobutylene, and 12g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -91℃. Then, 110g of chloromethane, 1.3g of sesquiethylaluminum chloride, and 0.032g of HCl were mixed and aged at -87℃ for 42 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.3 hours. Finally, 28g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0092] Example 3

[0093] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0094] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 2300g of pentane, 920g of bromovinylbenzene, 80g of cis-2-methyl-1,4-dibromo-2-butene, 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 66℃, 2.0g of TBHP was added, and the reaction was carried out for 4.8 hours. Then, 20g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 36 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular composite brominating agent.

[0095] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 1300g of pentane, 370g of isoprene, and 3.0g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 26.9 mmol of n-butyllithium was added to initiate the reaction. During the 40-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1400 g of pentane and 630 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 74°C. The reaction was carried out for 86 minutes until no free monomers were present. Finally, the temperature was raised to 83°C, and 50.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 66 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 59000, Mw / Mn = 6.96).

[0096] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged four times. Then, 200g of chloromethane, 300g of cyclohexane, and 20.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 84 minutes until completely dissolved. Next, the temperature was lowered to -82℃, and then 650g of chloromethane, 466g of isobutylene, and 14g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -93℃. Then, 115g of chloromethane, 1.5g of sesquiethylaluminum chloride, and 0.047g of HCl were mixed and aged at -88℃ for 45 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.7 hours. Finally, 30g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0097] Example 4

[0098] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0099] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 2500g of pentane, 930g of bromovinylbenzene, 70g of cis-2-methyl-1,4-dibromo-2-butene, 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 69℃, 2.5g of TBHP was added, and the reaction was carried out for 5.0 hours. Then, 25g of 1,3-butadiene was added to the polymerization 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 composite brominating agent.

[0100] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 1500g of pentane, 360g of isoprene, and 3.5g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 29.1 mmol of n-butyllithium was added to initiate the reaction. During the 50-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 1°C / min, forming a broadly distributed IR segment. Next, 1500 g of pentane and 640 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 75°C. The reaction was carried out for 90 minutes until no free monomers were present. Finally, the temperature was raised to 85°C, and 70.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 70 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 61000, Mw / Mn = 6.96).

[0101] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged four times. Then, 200g of chloromethane, 800g of cyclohexane, and 22.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 86 minutes until completely dissolved. Next, the temperature was lowered to -84℃, and then 700g of chloromethane, 463g of isobutylene, and 15g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -95℃. Then, 120g of chloromethane, 1.8g of sesquiethylaluminum chloride, and 0.052g of HCl were mixed and aged at -90℃ for 50 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.0 hours. Finally, 35g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0102] Example 5

[0103] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0104] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 2700g of pentane, 935g of bromovinylbenzene, 65g of cis-2-methyl-1,4-dibromo-2-butene, 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 72℃, 3.0g of TBHP was added, and the reaction was carried out for 5.4 hours. Then, 30g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 43 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular composite brominating agent.

[0105] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 1700g of pentane, 340g of isoprene, and 4.0g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 31.5 mmol of n-butyllithium was added to initiate the reaction. During the 50-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 1°C / min, forming a broadly distributed IR segment. Next, 1700 g of pentane and 660 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 77°C. The reaction was carried out for 92 minutes until no free monomers were present. Finally, the temperature was raised to 86°C, and 80.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 72 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 64000, Mw / Mn = 7.56).

[0106] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged four times. Then, 400g of chloromethane, 600g of cyclohexane, and 24.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 87 minutes until completely dissolved. Then, the temperature was lowered to -86℃, and 800g of chloromethane, 459g of isobutylene, and 17g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -96℃. Then, 130g of chloromethane, 2.1g of sesquiethylaluminum chloride, and 0.072g of HCl were mixed and aged at -91℃ for 53 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.4 hours. Finally, 40g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0107] Example 6

[0108] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0109] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged four times. Then, 2900g of pentane, 940g of bromovinylbenzene, 60g of cis-2-methyl-1,4-dibromo-2-butene, and 4.5g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 75℃, 3.5g of TBHP was added, and the reaction was carried out for 5.7 hours. Then, 40g of 1,3-butadiene was added to the polymerization 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 composite brominating agent.

[0110] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged four times. Then, 1800g of pentane, 320g of isoprene, and 4.5g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 33.4 mmol of n-butyllithium was added to initiate the reaction. During the 60-minute reaction, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 0.5°C / min, forming a broadly distributed IR segment. Next, 1800 g of pentane and 680 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 79°C. The reaction was carried out for 95 minutes until no free monomers were present. Finally, the temperature was raised to 88°C, and 90.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 75 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a high-molecular-weight three-arm broadly distributed brominated grafting agent (Mn = 67000, Mw / Mn = 7.86).

[0111] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged five times. Then, 500g of chloromethane, 500g of cyclohexane, and 28.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 88 minutes until completely dissolved. Next, the temperature was lowered to -88℃, and then 900g of chloromethane, 453g of isobutylene, and 19g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -98℃. Then, 140g of chloromethane, 2.3g of sesquiethylaluminum chloride, and 0.085g of HCl were mixed and aged at -93℃ for 56 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.7 hours. Finally, 45g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0112] Example 7

[0113] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0114] Preparation of a macromolecular composite brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged four times. Then, 3000g of pentane, 950g of bromovinylbenzene, 50g of cis-2-methyl-1,4-dibromo-2-butene, 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 80℃, 4.0g of TBHP was added, and the reaction was carried out for 6.0hr. Then, 50g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 50min until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular composite brominating agent.

[0115] Preparation of b. High-molecular-weight three-arm broad-distribution brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged four times. Then, 2000g of pentane, 300g of isoprene, and 5.0g of [unspecified ingredient] were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 35.5 mmol of n-butyllithium was added to initiate the reaction. During the 60-minute reaction, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 0.5°C / min, forming a broadly distributed IR segment. Next, 2000 g of pentane and 700 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 80°C. The reaction was carried out for 100 minutes until no free monomers were present. Finally, the temperature was raised to 90°C, and 100.1 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 80 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a polymeric three-arm broadly distributed brominated grafting agent (Mn = 69000, Mw / Mn = 8.34).

[0116] (2) Preparation of broadly distributed brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged five times. Then, 800g of chloromethane, 200g of cyclohexane, and 30.0g of a three-arm broadly distributed brominated grafting agent were added to the polymerization reactor and stirred for 90 minutes until completely dissolved. Next, the temperature was lowered to -90℃, and then 1000g of chloromethane, 450g of isobutylene, and 20g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -100℃. Then, 150g of chloromethane, 2.5g of sesquiethylaluminum chloride, and 0.093g of HCl were mixed and aged at -95℃ for 60 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 6.0 hours. Finally, 50g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0117] Comparative Example 1

[0118] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0119] Preparation of macromolecular composite brominator: Other conditions are the same as in Example 1, except that cis-2-methyl-1,4-dibromo-2-butene is not added during the preparation of the macromolecular composite brominator. Specifically: First, in a 15L stainless steel reactor with a jacket, nitrogen is purged twice. Then, 2000g of pentane, 900g of bromovinylbenzene, and 2.0g of tert-dodecyl mercaptan are added to the reactor in sequence. The mixture is stirred and heated. When the reactor temperature reaches 60°C, 1.0g of TBHP is added and the reaction is carried out for 4.0 hours. Then, 10g of 1,3-butadiene is added to the polymerization reactor for end-capping. The reaction is carried out for 30 minutes until no free monomers are present. After the reaction is completed, the mixture is washed and dried to obtain macromolecular composite brominator-1.

[0120] b. Preparation of the polymeric three-arm broad-distribution brominated grafting agent: Other conditions are the same as in Example 1, except that: no macromolecular composite brominating agent is added during the preparation of the polymeric three-arm broad-distribution brominated grafting agent; instead, macromolecular composite brominating agent-1 is added in an amount of 600g. That is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged twice, and then 1000g of pentane, 400g of isoprene, and 2.0g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and then 22.3 mmol of n-butyllithium was added to initiate the reaction. During the 40-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1000 g of pentane and 600 g of macromolecular composite brominating agent-1 were added to the polymerization reactor, and the temperature was raised to 70°C. The reaction was carried out for 80 minutes until no free monomers were present. Finally, the temperature was raised to 80°C, and 30.7 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 60 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was then wet-coagulated and dried to obtain a polymeric three-arm broadly distributed brominated grafting agent-1 (Mn is 47000, Mw / Mn is 5.23).

[0121] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 1, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric three-arm broadly distributed brominated grafting agent-1 is added, with an addition amount of 15g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 400g of chloromethane, 100g of cyclohexane, and 15.0g of polymeric three-arm broadly distributed brominated grafting agent-1 are added to the polymerization reactor. The mixture is stirred and dissolved for 80min until it is completely dissolved. Then, when the temperature is lowered to -80℃, 500g of chloromethane, 475g of isobutylene, and 10g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -90℃. Then, 100g of chloromethane, 0.7g of sesquiethylaluminum chloride, and HCl are added. 0.012g of the mixture was aged at -85℃ for 40 min, then added to the polymerization system and stirred for 4.0 hr. Finally, 25g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0122] Comparative Example 2

[0123] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0124] Preparation of macromolecular composite brominator: Other conditions are the same as in Example 2, except that 1,3-butadiene is not added for end-capping in the preparation of macromolecular composite brominator. That is: First, nitrogen gas is purged twice in a 15L stainless steel reactor with a jacket. Then, 2100g of pentane, 910g of bromovinylbenzene, 90g of cis-2-methyl-1,4-dibromo-2-butene, and 2.5g of tert-dodecyl mercaptan are added to the reactor in sequence. The mixture is stirred and heated. When the reactor temperature reaches 63°C, 1.5g of TBHP is added and the reaction is carried out for 4.3 hours. After the reaction is completed, the mixture is washed and dried to obtain macromolecular composite brominator-2.

[0125] b. Preparation of the polymeric three-arm broad-distribution brominated grafting agent: Other conditions are the same as in Example 2, except that: instead of adding a macromolecular composite brominizing agent, a macromolecular composite brominizing agent-2 is added, with an addition amount of 610g. That is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged twice, and then 1100g of pentane, 390g of isoprene, and 2.5g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and then 24.9 mmol of n-butyllithium was added to initiate the reaction. During the 40-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1200 g of pentane and 610 g of macromolecular composite brominizing agent-2 were added to the polymerization reactor, and the temperature was raised to 72°C. The reaction was carried out for 83 minutes until no free monomers were present. Finally, the temperature was raised to 81°C, and 40.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 63 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was wet-coagulated and dried to obtain a polymeric three-arm broadly distributed brominated grafting agent-2 (Mn is 4100, Mw / Mn is 4.76).

[0126] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 2, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric three-arm broadly distributed brominated grafting agent-2 is added, with an addition amount of 17.0 g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 300 g of chloromethane, 200 g of cyclohexane, and 17.0 g of polymeric three-arm broadly distributed brominated grafting agent-2 are added to the polymerization reactor. The mixture is stirred and dissolved for 82 min until completely dissolved. Then, when the temperature is lowered to -81°C, 600 g of chloromethane, 471 g of isobutylene, and 12 g of isoprene are added sequentially. The mixture is stirred and mixed until the temperature of the polymerization system drops to -91°C. Then, 110 g of chloromethane, 1.3 g of sesquiethylaluminum chloride, and HCl are added. 0.032g of the mixture was aged at -87℃ for 42 min, then added to the polymerization system and stirred for 4.3 hr. Finally, 28g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0127] Comparative Example 3

[0128] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0129] Preparation of macromolecular complex brominating agent: Same as in Example 3.

[0130] b. Preparation of the polymeric three-arm wide-distribution brominated grafting agent: Other conditions are the same as in Example 3, except that the amount of macromolecular composite brominated agent added during the preparation of the polymeric three-arm wide-distribution grafting agent is 200g, that is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged three times, and then 1300g of pentane, 370g of isoprene, and 3.0g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and then 26.9 mmol of n-butyllithium was added to initiate the reaction. During the 40-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 2°C / min, forming a broadly distributed IR segment. Next, 1400 g of pentane and 200 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 74°C. The reaction was carried out for 86 minutes until no free monomers were present. Finally, the temperature was raised to 83°C, and 50.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 66 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was wet-coagulated and dried to obtain a polymeric three-arm broadly distributed brominated grafting agent-3 (Mn is 51000, Mw / Mn is 6.16).

[0131] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 3, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric three-arm broadly distributed brominated grafting agent-3 is added, with an addition amount of 20.0 g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 200 g of chloromethane, 300 g of cyclohexane, and 20.0 g of polymeric three-arm broadly distributed brominated grafting agent-3 are added to the polymerization reactor. The mixture is stirred and dissolved for 84 min until completely dissolved. Then, when the temperature is lowered to -82°C, 650 g of chloromethane, 466 g of isobutylene, and 14 g of isoprene are added sequentially. The mixture is stirred and mixed until the temperature of the polymerization system drops to -93°C. Then, 115 g of chloromethane, 1.5 g of sesquiethylaluminum chloride, and HCl are added. 0.047g of the mixture was aged at -88℃ for 45 minutes, then added to the polymerization system and stirred for 4.7 hours. Finally, 30g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0132] Comparative Example 4

[0133] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0134] Preparation of macromolecular complex brominating agent: Same as in Example 4.

[0135] b. Preparation of the polymeric three-arm broad-distribution brominated grafting agent: Other conditions are the same as in Example 4, except that: instead of adding a macromolecular composite brominating agent, bromovinylbenzene is added in the preparation of the polymeric three-arm broad-distribution brominated grafting agent, 640.0 g of bromovinylbenzene is added. That is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged three times, and then 1500 g of pentane, 360 g of isoprene, and 3.5 g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and then 29.1 mmol of n-butyllithium was added to initiate the reaction. During the 50-minute reaction, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 1°C / min, forming a broadly distributed IR segment. Next, 1500 g of pentane and 640 g of bromovinylbenzene were added to the polymerization reactor, and the temperature was raised to 75°C. The reaction was carried out for 90 minutes until no free monomers were present. Finally, the temperature was raised to 85°C, and 70.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 70 minutes. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was wet-coagulated and dried to obtain a polymeric three-arm broadly distributed brominated grafting agent-4 (Mn is 49000, Mw / Mn is 5.97).

[0136] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 4, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric three-arm broadly distributed brominated grafting agent-4 is added, with an addition amount of 22.0 g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 200 g of chloromethane, 800 g of cyclohexane, and 22.0 g of polymeric three-arm broadly distributed brominated grafting agent-4 are added to the polymerization reactor. The mixture is stirred and dissolved for 86 min until completely dissolved. Then, when the temperature is lowered to -84°C, 700 g of chloromethane, 463 g of isobutylene, and 15 g of isoprene are added sequentially. The mixture is stirred and mixed until the temperature of the polymerization system drops to -95°C. Then, 120 g of chloromethane, 1.8 g of sesquiethylaluminum chloride, and HCl are added. 0.052g of the mixture was aged at -90℃ for 50 min, then added to the polymerization system and stirred for 5.0 hr. Finally, 35g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0137] Comparative Example 5

[0138] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0139] Preparation of macromolecular complex brominating agent: Same as in Example 5.

[0140] b. Preparation of a polymeric three-arm wide-distribution brominated grafting agent: Same as in Example 5.

[0141] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 5, except that the amount of polymer three-arm broadly distributed brominated grafting agent added during the preparation of broadly distributed brominated branched butyl rubber is 5g, that is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 400g of chloromethane, 600g of cyclohexane, and 5.0g of polymer three-arm broadly distributed brominated grafting agent are added to the polymerization reactor and stirred and dissolved for 87min until completely dissolved; then, when the temperature is lowered to -86℃, 800g of chloromethane, 459g of isobutylene, and 17g of isoprene are added in sequence and stirred until the temperature of the polymerization system drops to -96℃, and then 130g of chloromethane, 2.1g of sesquiethylaluminum chloride, and HCl are added. 0.072g of the mixture was aged at -91℃ for 53 min, then added to the polymerization system and stirred for 5.4 hr. Finally, 40g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0142] Comparative Example 6

[0143] (1) Preparation of a polymeric three-arm broad-distribution brominated grafting agent:

[0144] Preparation of macromolecular complex brominating agent: Same as in Example 6.

[0145] b. Preparation of the polymeric three-arm broad-distribution brominated grafting agent: Other conditions are the same as in Example 6, except that temperature-switching polymerization is not used in the preparation of the polymeric three-arm broad-distribution brominated grafting agent. Isoprene is reacted at 50°C for 60 min, that is: first, argon gas is purged four times in a jacketed 15L stainless steel reactor, and then 1800g of pentane, 320g of isoprene, and 4.5g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and then 33.4 mmol of n-butyllithium was added to initiate the reaction. The reaction was carried out for 60 min to form IR segments. Next, 1800 g of pentane and 680 g of macromolecular composite brominating agent were added to the polymerization reactor and the temperature was raised to 79°C. The reaction was carried out for 95 min until no free monomers were present. Finally, the temperature was raised to 88°C, and 90.5 mmol of 1,3,5-trichlorobenzene was added. The reaction was carried out for 75 min. After the reaction was completed, the coupled reaction mixture was treated with water. The gel was wet coagulated and dried to obtain a high molecular weight three-arm wide-distribution brominated grafting agent-5 (Mn is 65000, Mw / Mn is 5.86).

[0146] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 6, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric three-arm broadly distributed brominated grafting agent-5 is added, with an addition amount of 28.0 g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 500 g of chloromethane, 500 g of cyclohexane, and 28.0 g of polymeric three-arm broadly distributed brominated grafting agent-5 are added to the polymerization reactor. The mixture is stirred and dissolved for 88 min until it is completely dissolved. Then, when the temperature is lowered to -88°C, 900 g of chloromethane, 453 g of isobutylene, and 19 g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -98°C. Then, 140 g of chloromethane, 2.3 g of sesquiethylaluminum chloride, and HCl are added. 0.085g of the mixture was aged at -93℃ for 56 min, then added to the polymerization system and stirred for 5.7 h. Finally, 45g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0147] Comparative Example 7

[0148] (1) Preparation of high molecular weight, wide-distribution brominated grafting agent:

[0149] Preparation of macromolecular complex brominating agent: Same as in Example 7.

[0150] b. Preparation of the broadly distributed brominated grafting agent: Other conditions were the same as in Example 7, except that 1,3,5-trichlorobenzene was not added for coupling during the preparation of the broadly distributed brominated grafting agent. That is, firstly, argon gas was purged four times in a 15L stainless steel reactor with a jacket, and then 2000g of pentane, 300g of isoprene, and 5.0g of... were added sequentially to the polymerization reactor. THF was heated to 50°C, and then 35.5 mmol of n-butyllithium was added to initiate the reaction. During the 60-minute reaction time, the reaction temperature was gradually increased from 50°C to 70°C at a rate of 0.5°C / min, forming a broadly distributed IR segment. Next, 2000 g of pentane and 700 g of macromolecular composite brominating agent were added to the polymerization reactor, and the temperature was raised to 80°C. The reaction was carried out for 100 minutes until no free monomers were present. The gel was then wet-coagulated and dried to obtain a high molecular weight broadly distributed brominated grafting agent-6 (Mn = 67000, Mw / Mn = 4.46). This high molecular weight broadly distributed brominated grafting agent-6 does not have a three-arm star-shaped branched structure.

[0151] (2) Preparation of broadly distributed brominated branched butyl rubber: Other conditions are the same as in Example 7, except that: no polymeric three-arm broadly distributed brominated grafting agent is added during the preparation of the broadly distributed brominated branched butyl rubber. Instead, polymeric broadly distributed brominated grafting agent-6 is added, with an addition amount of 30.0 g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 800 g of chloromethane, 200 g of cyclohexane, and 30.0 g of polymeric broadly distributed brominated grafting agent-6 are added to the polymerization reactor. The mixture is stirred and dissolved for 90 min until completely dissolved. Then, when the temperature is lowered to -90°C, 1000 g of chloromethane, 450 g of isobutylene, and 20 g of isoprene are added sequentially. The mixture is stirred and mixed until the temperature of the polymerization system drops to -100°C. Then, 150 g of chloromethane, 2.5 g of sesquiethylaluminum chloride, and HCl are added. 0.093g of the mixture was aged at -95℃ for 60 min, then added to the polymerization system and stirred for 6.0 hr. Finally, 50g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a broadly distributed brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0152] Table 1 Properties of Widely Distributed Brominated Branched Butyl Rubber

[0153]

[0154]

[0155] 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.

[0156] As shown in Table 1, the wide-distribution brominated branched butyl rubber of the present invention has a wide molecular weight distribution, a high vulcanization rate and a low Mooney stress relaxation time, exhibiting good processing and vulcanization characteristics, while maintaining high tensile strength and good air tightness.

[0157] 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 a broadly distributed brominated branched butyl rubber, the method comprising the following steps: S1: Add the polymeric three-arm wide-distribution brominated grafting agent to the mixed solvent and stir thoroughly until the polymeric three-arm wide-distribution 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 a broadly distributed brominated branched butyl rubber. The feature is that the polymeric three-arm wide-distribution brominated grafting agent is a three-arm wide-distribution brominated star-shaped block copolymer composed of isoprene and a macromolecular composite brominated agent, and its general structural formula is shown in Formula I: Equation I Wherein, IR represents isoprene homopolymer block; the macromolecular composite brominating agent is a random block copolymer of bromovinylbenzene, cis-2-methyl-1,4-dibromo-2-butene, and 1,3-butadiene; m and n are the number of repeating units, where m is an integer ≥1 and n is an integer ≥1; the number average molecular weight (Mn) of the polymeric three-arm wide-distribution bromination grafting agent is 50,000~70,000, and the molecular weight distribution (Mw / Mn) is 6.17~8.

34.

2. The method for preparing broadly distributed brominated branched 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℃.

3. The method for preparing broadly distributed brominated branched butyl rubber according to claim 1, characterized in that, In step S2, the mass ratio of the diluent, isobutylene, and isoprene is 100~200:90~95:2~4.

4. The method for preparing broadly distributed brominated branched butyl rubber according to claim 1, characterized in that, In step S3, the mass ratio of the diluent, co-initiator, and terminator is 20~30:0.1~0.5:5~10.

5. The method for preparing broadly distributed brominated branched butyl rubber according to claim 1, characterized in that, The preparation method of the polymeric three-arm broad-distribution brominated grafting agent specifically includes the following steps: Preparation of a macromolecular composite brominating agent: Taking 100 parts by mass of reactive brominating agent, firstly, add 200-300 parts of solvent, 90-95 parts of bromovinylbenzene, 5-10 parts of cis-2-methyl-1,4-dibromo-2-butene, and 0.2-0.5 parts of molecular weight regulator to a reaction vessel after inert gas replacement. Stir and mix, heat, and when the reaction vessel temperature reaches 60-80℃, add 0.1-0.4 parts of the first initiator. React for 4.0-6.0 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 30-50 minutes until no free monomers are present. After the reaction is completed, wash and dry to obtain the macromolecular composite brominating agent. Preparation of a broadly distributed IR-linked polymeric three-arm grafting agent: Based on 100% of the total mass of the reactants, first, 100 wt%–200 wt% solvent, 30 wt%–40 wt% isoprene, 0.2 wt%–0.5 wt% structure modifier, and a second initiator are added sequentially to a reactor purged with an inert gas. The reaction is a temperature-variable polymerization, with a reaction time of 40–60 min, and the temperature gradually increased from 50 °C to 70 °C, forming broadly distributed IR segments. Next, 100 wt%–200 wt% solvent, 60 wt%–70 wt% isoprene, and 60 wt%–70 wt% structure modifier are added sequentially to the reactor. A macromolecular composite brominating agent (wt%) is heated to 70-80℃ and reacted for 80-100 minutes until no free monomers are present. Finally, the temperature is raised to 80-90℃, and a coupling agent is added to carry out a coupling reaction for 60-80 minutes. After the reaction is completed, the coupled reaction mixture is treated with water, followed by wet coagulation and drying to obtain a high-molecular-weight three-arm broad-distribution bromination grafting agent. The coupling agent is at least one of 1,3,5-trichlorobenzene and 1,3,5-tribromobenzene.

6. The method for preparing broadly distributed brominated branched butyl rubber according to claim 5, 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 tert-butyl hydroperoxide, di-tert-butyl hydroperoxide, and tert-pentyl hydroperoxide; The structure modifier is a polar organic compound selected from at least one of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, 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 broadly distributed brominated branched butyl rubber according to claim 6, characterized in that, The molecular weight regulator is tert-dodecyl mercaptan.

8. The method for preparing broadly distributed brominated branched butyl rubber according to claim 6, characterized in that, The first initiator is tert-butyl hydroperoxide.

9. The method for preparing broadly distributed brominated branched butyl rubber according to claim 6, characterized in that, The structure modifier is tetrahydrofuran.

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

11. The method for preparing broadly distributed brominated branched butyl rubber according to claim 5, characterized in that, The coupling agent is 1,3,5-trichlorobenzene.

12. The method for preparing broadly distributed brominated branched butyl rubber according to claim 5, characterized in that, The molar ratio of the coupling agent to the second initiator is 1:1 to 5:

1.

13. The method for preparing broadly distributed brominated branched butyl rubber according to claim 5, characterized in that, The solvent is selected from at least one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene.

14. The method for preparing broadly distributed brominated branched butyl rubber according to claim 13, characterized in that, The solvent is hexane.

15. The method for preparing broadly distributed brominated branched 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, difluoromethane, tetrafluoroethane, and fluorobutane.

16. The method for preparing broadly distributed brominated branched butyl rubber according to claim 15, characterized in that, The diluent is chloromethane.

17. The method for preparing broadly distributed brominated branched 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 at least 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 0.5:

1.

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

19. The method for preparing broadly distributed brominated branched butyl rubber according to claim 17, characterized in that, The protic acid is HCl.

20. The method for preparing broadly distributed brominated branched 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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