A process for the preparation of an anionic brominated branched butyl rubber

Abstract

The application discloses a preparation method of an anionic brominated branched butyl rubber, and the preparation method comprises the following steps: adding a high-molecular brominated grafting agent into a mixed solvent, fully stirring until the high-molecular brominated grafting agent is completely dissolved to obtain a mixed solution; cooling, adding a diluent, isobutene and isoprene into the mixed solution in sequence, fully stirring and mixing to obtain 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 to obtain the anionic brominated branched butyl rubber; the high-molecular brominated grafting agent is a linear block copolymer which is composed of isoprene, butadiene, styrene, bromoethylene and an allyl halide. 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 anionic brominated branched butyl rubber, specifically to a method for anionic synthesis of secondary and primary brominated butadiene / styrene block copolymer grafted butyl rubber. 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] Chinese patent CN112574333A discloses a bromination process for star-branched butyl rubber. The process includes: a) dissolving the star-branched butyl rubber in an aliphatic hydrocarbon to obtain a rubber solution; b) mixing the rubber solution with a branching agent and a scavenging agent (ethanol) to obtain a mixture; c) adding an oxidant (hydrogen peroxide) and a brominating agent (Br2) to the mixture, with the molar ratio of bromine to the unsaturated double bonds in the star-branched butyl rubber being (0.75–2):1, performing a bromination reaction, and finally neutralizing and recovering the product to obtain brominated star-branched butyl rubber. This process can dissolve residual branching agents in the star-branched butyl rubber before bromination, preventing them from combining with HBr byproducts generated during bromination, thereby improving neutralization efficiency and inhibiting the isomerization transformation from Type II secondary structure to Type III primary structure.

[0005] Chinese patent 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.

[0006] Chinese patent 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. Under temperature conditions of 0 to -100°C, the method directly participates in cationic polymerization in a mixed solvent of chloromethane / cyclohexane with a v:v ratio of 20 to 80 / 80 to 20. The cationic polymerization is initiated by silanol groups, and the star-branched polyisobutylene or butyl rubber product is prepared by the grafting reaction involving unsaturated chains.

[0007] Chinese patent CN 106749816A discloses a method for preparing brominated butyl rubber. This 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.

[0008] 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 of activated carbon.

[0009] Synthetic Rubber Industry (2006, 29(4): 267-270) discloses a method for preparing brominated butyl rubber by dissolving butyl rubber (Polysar-301) in cycloalkanes and then brominating it with liquid bromine. 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 would decrease 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, that is, there was a phenomenon of transfer from the secondary allyl bromide configuration to the more stable primary allyl bromide configuration.

[0010] 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

[0011] The present invention aims to provide a method for preparing anionic brominated branched butyl rubber. This method uses a macromolecular brominator as a raw material, which exhibits anionic reactivity. Secondly, butadiene, styrene, and the macromolecular brominator are synthesized via anionic polymerization to produce a high-molecular-weight brominated grafting agent with secondary and primary bromine structures. Finally, the high-molecular-weight brominated grafting agent, isobutylene, and isoprene are cationicly polymerized in a catalytic system composed of alkyl aluminum halide and a protic acid to prepare brominated branched butyl rubber. This invention prepares brominated branched butyl rubber through addition polymerization, rather than the ionic substitution reaction used in existing technologies. This method avoids the production of hydrogen bromide as a byproduct, prevents bromine structure rearrangement in brominated butyl rubber, solves the problem of bromine structure stability in brominated branched butyl rubber, and significantly improves the vulcanization rate of butyl rubber with the introduction of the primary bromine structure. Meanwhile, by branching butyl rubber, not only is the problem of slow stress relaxation rate of butyl rubber during processing solved, but also sufficient raw rubber strength and good air tightness are maintained, giving butyl rubber a balance between physical and mechanical properties and vulcanization processing performance.

[0012] Unless otherwise specified, "%" in this invention refers to mass percentage.

[0013] To achieve the above objectives, the present invention provides a method for preparing anionic brominated branched butyl rubber, the method comprising the following steps:

[0014] S1: Add the polymer brominated grafting agent to the mixed solvent and stir thoroughly until the polymer brominated grafting agent is completely dissolved to obtain a mixed solution;

[0015] 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;

[0016] 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 anionic brominated branched butyl rubber.

[0017] The feature is that the polymeric brominated grafting agent is a linear block copolymer composed of isoprene, butadiene, styrene, vinyl bromide, and allyl halide, with the general structural formula shown in Formula I:

[0018] Formula I

[0019] Wherein: IR is isoprene homopolymer block; SBR is styrene and butadiene random copolymer block; R is C1 to C4 alkyl; m and n are the number of repeating units, m is an integer ≥1, and n is an integer ≥1; the number average molecular weight (Mn) of the polymer brominated grafting agent is 30,000 to 50,000, and the ratio of weight average molecular weight to number average molecular weight (Mw / Mn) is 2.27 to 3.14.

[0020] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S1, the mass ratio of the mixed solvent and the polymeric brominated grafting agent is 100~200:4~6.

[0021] In the preparation method of anionic 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 70~30 / 30~70.

[0022] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S2, the temperature is cooled to -70℃ to -80℃.

[0023] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S2, the mass ratio of the diluent, isobutylene and isoprene is 100~200:90~94:2~4.

[0024] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S2, the temperature is lowered again to -100~-90℃.

[0025] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S3, the mass ratio of the diluent, co-initiator and terminator is 20~30:0.05~0.5:5~10.

[0026] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S3, the aging temperature is -95℃ to -85℃ and the aging time is 30 to 50 minutes.

[0027] In the preparation method of anionic brominated branched butyl rubber of the present invention, in step S3, the drying temperature is 60~70℃ and the time is 25~35hr.

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

[0029] Preparation of macromolecular brominating agent: Taking 100 parts by total mass of reactive brominating agent, firstly, add 100-200 parts of solvent, 80-90 parts of ethylene bromo, 10-20 parts of allyl halide, and 0.4-0.7 parts of molecular weight regulator to the reaction vessel after inert gas replacement. Stir and mix, heat, and when the temperature of the reaction vessel reaches 50-70℃, add 0.05-0.3 parts of the first initiator. React for 3.0-5.0 hours until the ethylene bromo monomer conversion rate reaches 100%. Then, add 2-5 parts of 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] b. Preparation of the high-molecular-weight brominated grafting agent: Based on 100% of the total mass of the reactants, first, add 200 wt%–300 wt% solvent, 10 wt%–20 wt% isoprene, and 0.3 wt%–0.5 wt% structure modifier sequentially to the reactor after inert gas purging. After heating to 50–60°C, add the second initiator and react for 40–60 min. Then, add 20 wt%–30 wt% styrene, 10 wt%–20 wt% butadiene, and 0.05 wt%–0.2 wt% structure modifier to the reactor. The temperature is increased to 60-70℃ and reacted for 50-70 minutes to form -IR-SBR- segments. Finally, 30wt%-60wt% of macromolecular brominating agent is added to the reactor, the temperature is increased to 70-80℃, and the reaction is carried out for 60-90 minutes until no free monomers are present. After the reaction is completed, the polymeric bromination grafting agent is obtained by wet coagulation and drying.

[0031] The method for preparing anionic 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 anionic brominated branched butyl rubber of the present invention, wherein the allyl halide is at least one selected from allyl bromide, 2-methyl-1-allyl bromide, 2-ethyl-1-allyl bromide, 2-propyl-1-allyl bromide, and 2-butyl-1-allyl bromide, preferably allyl bromide.

[0033] The method for preparing anionic brominated branched 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).

[0034] The method for preparing anionic brominated branched butyl rubber of the present invention uses a polar organic compound as a structure modifier. This compound produces a solvation effect in the polymerization system, which can adjust the reactivity ratio of styrene and isoprene, enabling 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).

[0035] In the preparation method of the anionic 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.

[0036] In the preparation method of the anionic brominated branched 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 hydrocarbon solvent described in the present invention includes straight-chain alkanes, aromatics, and cycloalkanes, and is selected from at least one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene, with hexane being preferred.

[0037] The method for preparing anionic brominated branched butyl rubber of the present invention uses a haloalkane as a diluent, 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 method for preparing anionic brominated branched butyl rubber of the present invention comprises a co-initiator composed of 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 0.01:1 to 0.1:1.

[0039] The method for preparing anionic brominated branched butyl rubber of the present invention may use, for example but not limited to, at least one of methanol, ethanol, and butanol as the terminating agent.

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

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

[0042] (1) Preparation of polymeric brominated grafting agent:

[0043] Preparation of macromolecular brominating agent: Taking 100 parts by total mass of reactive brominating agent, firstly, in a 15L stainless steel reactor with a jacket, purge with inert gas 2-4 times. Then, add 100-200 parts of solvent, 80-90 parts of ethylene bromo, 10-20 parts of allyl halide, and 0.4-0.7 parts of molecular weight regulator to the reactor in sequence. Stir and mix, heat, and when the reactor temperature reaches 50-70℃, add 0.05-0.3 parts of the first initiator. React for 3.0-5.0 hours, at which point the ethylene bromo monomer conversion rate reaches 100%. Then, add 2-5 parts of 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.

[0044] b. Preparation of the high-molecular-weight brominated grafting agent: 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 200wt%-300wt% solvent, 10wt%-20wt% isoprene, and 0.3wt%-0.5wt% structure modifier to the reactor. After heating to 50-60℃, add the second initiator and react for 40-60 min. Next, add 20wt%-30wt% styrene, 10wt%-20wt% butadiene, and 0.05wt%-0.2wt% structure modifier to the reactor. Heat to 60-70℃ and react for 50-70 min to form the -IR-SBR- segment. Finally, add 30wt%-60wt% of the solvent, 10wt%-20wt% isoprene, and 0.05wt%-0.2wt% structure modifier to the reactor. Add wt% macromolecular brominating agent, heat to 70~80℃, react for 60~90min until no free monomers are present. After the reaction is completed, wet coagulation and drying are performed to obtain the high molecular weight bromination grafting agent.

[0045] (2) Preparation of anionic 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 100 wt%-200 wt% mixed solvent (diluent / solvent V:V ratio of 70-30 / 30-70), 4 wt%-6 wt% high molecular weight brominated grafting agent, and stir to dissolve for 40-60 minutes until the grafting agent is completely dissolved; then, when the temperature is lowered to -70℃ to -80℃, add 100 wt%-200 wt% diluent, 90 wt%-94 wt% isobutylene, and 2 wt%-4 wt% isoprene in sequence, stirring and mixing until the polymerization system temperature drops to -100℃ to -90℃, then add 20 wt%-30 wt% diluent and 0.05 wt%-0.5 wt%... After mixing and aging the co-initiator at -95 to -85°C for 30 to 50 minutes, it is added to the polymerization system and stirred for 3.0 to 5.0 hours. Finally, 5 to 10 wt% of terminator is added, and the mixture is discharged, coagulated, washed, and dried to obtain anionic brominated branched butyl rubber product.

[0046] The polymeric brominated grafting agent of the present invention is a linear block copolymer composed of isoprene, butadiene, styrene, vinyl bromide and allyl halide, and its general structural formula is shown in Formula I:

[0047] Formula I

[0048] Wherein: IR represents isoprene homopolymer block; SBR represents styrene-butadiene random copolymer block; R represents C1-C4 alkyl groups; m and n are the number of repeating units. The number average molecular weight (Mn) of the high molecular weight brominated grafting agent is 30,000-50,000, and the molecular weight distribution (Mw / Mn) is 2.27-3.14.

[0049] The preparation process of the polymeric brominated grafting agent of the present invention involves the free radical polymerization of two reactive brominating agents, vinyl bromide and allyl halide, to generate a macromolecular brominating agent. Subsequently, butadiene is used for end-capping activation to prepare the macromolecular brominating agent. This macromolecular brominating agent can undergo anionic polymerization with the polymer [-IR-SBR-]m to generate a polymeric brominated grafting agent. Firstly, this macromolecular brominating agent avoids the generation of large amounts of corrosive and toxic hydrogen bromide (HBr) gas, which is harmful to human health and the environment, eliminating the need for alkaline washing and recovery of HBr, thus shortening the process and reducing production costs. Secondly, it improves the persistence of the bromination effect and the utilization rate of bromine, giving it anionic reactivity.

[0050] The polymeric brominated grafting agent of this invention mainly plays three roles:

[0051] On the one hand, it plays a role in preventing the rearrangement of bromine structure in brominated branched butyl rubber. This is mainly because the secondary and primary bromine structures in this polymeric brominated grafting agent are generated through addition polymerization, rather than ion substitution as in existing technologies. There is no byproduct HBr, which blocks the conditions for bromine structure isomerization, thereby greatly improving the stability of the bromine structure in brominated branched butyl rubber and ensuring product quality.

[0052] Secondly, the introduction of primary bromine structures into the polymer brominated grafting agent increases the vulcanization speed and shortens the scorch time, solving the problems of long scorch time and slow vulcanization speed of butyl rubber during processing and improving vulcanization efficiency.

[0053] Thirdly, it solves the contradiction between the poor processability and good physical properties of butyl rubber. The -IR- and -SBR- segments contained in the polymer brominated grafting agent have certain vinyl groups, which can improve the flexibility of the segments and obtain a fast stress relaxation rate, enabling the butyl rubber to obtain good viscoelastic properties and excellent processability. At the same time, the -SBR- segments contain benzene ring structures. Benzene rings have the characteristics of high rigidity and large steric hindrance, which can avoid the problem of butyl rubber's strength and air tightness decreasing due to the widening of molecular weight distribution caused by branching.

[0054] Therefore, the polymeric brominated grafting agent designed in this invention organically combines the properties of a macromolecular brominizing agent and two polymeric segments, -IR- and -SBR-, to work synergistically. This effectively solves the problems of slow stress relaxation rate, slow vulcanization rate, and long scorch time in butyl rubber during processing. This results in butyl rubber exhibiting both good processability and ensuring its raw rubber strength and airtightness, thus achieving a balance between its physical and mechanical properties and processing performance. The preparation method of brominated branched butyl rubber provided by this invention features a short process flow, stable bromine structure, energy saving and environmental protection, and suitability for industrial production.

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

[0056] 1. The polymeric 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. It does not produce the byproduct HBr, thus blocking the conditions for bromine structure isomerization, thereby greatly improving the stability of the bromine structure of brominated branched butyl rubber and ensuring product quality.

[0057] 2. The introduction of primary bromine structures into the polymeric brominated grafting agent of the present invention increases the vulcanization speed and shortens the scorch time, solving the problems of long scorch time and slow vulcanization speed of butyl rubber during processing, and improving vulcanization efficiency.

[0058] 3. The macromolecular brominating agent of the present invention is generated by free radical polymerization of two organic brominating agents containing unsaturated double bonds. No HBr is generated during the entire reaction process, and there is no loss of residual bromine, which improves the utilization rate of bromine in brominated branched butyl rubber.

[0059] 4. The polymer brominated grafting agent of the present invention contains -IR- and -SBR- segments with certain vinyl and benzene rings, which can improve the flexibility of the segments, obtain a fast stress relaxation rate, and ensure the strength and airtightness of butyl rubber, thus achieving a balance between the strength and airtightness of butyl rubber and its excellent processing performance.

[0060] 5. The polymeric 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, controllable bromine structure, 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] Ethylene bromide, polymerization grade, Wuhan Fuxinyuan Technology Co., Ltd.

[0066] Allyl bromide, polymer grade, Wuhan Fuxinyuan Technology Co., Ltd.

[0067] Benzoyl peroxide (BPO), Lanzhou Additives Factory;

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

[0069] Sesquiethyl aluminum chloride, 98% purity, Bailingwei Technology Co., Ltd.

[0070] All other reagents are commercially available industrial products.

[0071] (2) Analysis and testing methods:

[0072] 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 thermally degrade 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:

[0073]

[0074] 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.

[0075] Molecular weight and its distribution were determined using a Waters 2414 gel permeation chromatography (GPC) system. 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 .

[0076] 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 (time taken for 80% of the torque to decay (remaining 20%)) and X30 (percentage of torque remaining after 30 seconds of rotor stoppage).

[0077] Vulcanization characteristics: Tested according to GB / T 16584—1996.

[0078] Air tightness determination: An automated air tightness tester was used to determine the air permeability number according to ISO 2782:1995.

[0079] 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.

[0080] Tensile strength: The method specified in standard GB / T528-2009 shall be applied.

[0081] Example 1

[0082] (1) Preparation of polymeric brominated grafting agent:

[0083] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 1000g of hexane, 800g of ethylene bromo, 200g of allyl bromide, 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 50℃, 0.6g of BPO was added, and the reaction was carried out for 3.0 hours. Then, 20g 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 brominating agent.

[0084] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged twice. Then, 2000g of cyclohexane, 100g of isoprene, and 3.0g of THF were added to the polymerization reactor in sequence. The temperature was raised to 50℃, and 14.7 mmol of n-butyllithium was added to start the reaction for 40 min. Then, 300g of styrene and 100g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 60℃. The reaction was carried out for 50 min to form -IR-SBR- segments. Finally, 500g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 70℃. The reaction was carried out for 60 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 30200, Mw / Mn is 2.27).

[0085] (2) Preparation of anionic brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 350g of chloromethane, 150g of cyclohexane, and 20g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 40 minutes until completely dissolved. Then, when the temperature was lowered to -70℃, 500g of chloromethane, 470g of isobutylene, and 10g of isoprene were added sequentially and stirred until the polymerization system temperature dropped to -90℃. Then, 100g of chloromethane, 1.75g ​​of sesquiethylaluminum chloride, and 0.019g of HCl were mixed and aged at -86℃ for 30 minutes, and then added to the polymerization system and stirred for 3.0 hours. Finally, 27g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0086] Example 2

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

[0088] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 1200g of hexane, 810g of ethylene bromine, 190g of allyl bromide, 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 53℃, 0.9g of BPO was added, and the reaction was carried out for 3.4 hours. Then, 24g 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 brominating agent.

[0089] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2100g of cyclohexane, 110g of isoprene, and 3.2g of THF were added to the polymerization reactor in sequence. The temperature was raised to 52℃, and 15.6mmol of n-butyllithium was added to start the reaction for 43min. Then, 280g of styrene and 110g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 62℃. The reaction was carried out for 53min to form -IR-SBR- segments. Finally, 600g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 71℃. The reaction was carried out for 65min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 33200, Mw / Mn is 2.35).

[0090] (2) Preparation of anionic brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 300g of chloromethane, 200g of cyclohexane, and 22g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 43 minutes until completely dissolved. Then, when the temperature was lowered to -72℃, 600g of chloromethane, 467g of isobutylene, and 11g of isoprene were added sequentially and stirred until the polymerization system temperature dropped to -91℃. Then, 110g of chloromethane, 1.83g of sesquiethylaluminum chloride, and 0.021g of HCl were mixed and aged at -87℃ for 34 minutes, and then added to the polymerization system and stirred for 3.3 hours. Finally, 30g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0091] Example 3

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

[0093] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged three times. Then, 1400g of hexane, 830g of ethylene bromine, 170g of allyl bromide, 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 56℃, 1.0g of BPO was added, and the reaction was carried out for 3.8 hours. Then, 30g 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 brominating agent.

[0094] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2300g of cyclohexane, 130g of isoprene, and 3.7g of THF were added to the polymerization reactor in sequence. The temperature was raised to 54℃, and 16.8mmol of n-butyllithium was added to start the reaction for 48min. Next, 260g of styrene and 200g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 63℃. The reaction was carried out for 57min to form -IR-SBR- segments. Finally, 410g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 73℃. The reaction was carried out for 70min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 38100, Mw / Mn is 2.46).

[0095] (2) Preparation of anionic brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. Then, 260g of chloromethane, 240g of cyclohexane, and 24g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 47 minutes until completely dissolved. Then, the temperature was lowered to -74℃, and 700g of chloromethane, 463g of isobutylene, and 13g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -93℃. Then, 120g of chloromethane, 1.92g of sesquiethylaluminum chloride, and 0.025g of HCl were mixed and aged at -89℃ for 39 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.7 hours. Finally, 35g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0096] Example 4

[0097] (1) Preparation of polymeric 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, 1500g of hexane, 850g of ethylene bromine, 150g of allyl bromide, and 5.7g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 60℃, 1.5g of BPO was added, and the reaction was carried out for 4.0 hours. Then, 35g of 1,3-butadiene was added to the polymerization 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.

[0099] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2500g of cyclohexane, 150g of isoprene, and 4.0g of THF were added to the polymerization reactor in sequence. The temperature was raised to 55℃, and 18.3 mmol of n-butyllithium was added to start the reaction for 50 min. Then, 250g of styrene and 180g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 65℃. The reaction was carried out for 60 min to form -IR-SBR- segments. Finally, 420g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 75℃. The reaction was carried out for 75 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 38100, Mw / Mn is 2.57).

[0100] (2) Preparation of anionic brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged three times. 700g of chloromethane, 300g of cyclohexane, and 26g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 50 minutes until completely dissolved. Then, the temperature was lowered to -75℃, and 760g of chloromethane, 459g of isobutylene, and 15g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -95℃. Then, 130g of chloromethane, 2.02g of sesquiethylaluminum chloride, and 0.027g of HCl were mixed and aged at -90℃ for 41 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.0 hours. Finally, 40g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0101] Example 5

[0102] (1) Preparation of polymeric 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, 1600g of hexane, 860g of ethylene bromo, 140g of allyl bromide, and 6.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 62℃, 1.8g of BPO was added, and the reaction was carried out for 4.3 hours. Then, 40g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 52 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] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2600g of cyclohexane, 160g of isoprene, and 4.3g of THF were added to the polymerization reactor in sequence. The temperature was raised to 57℃, and 19.1 mmol of n-butyllithium was added to start the reaction for 54 min. Then, 220g of styrene and 140g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 66℃. The reaction was carried out for 62 min to form -IR-SBR- segments. Finally, 480g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 77℃. The reaction was carried out for 80 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 42200, Mw / Mn is 2.75).

[0105] (2) Preparation of anionic brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged three times. 600g of chloromethane, 400g of cyclohexane, and 28g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 55 minutes until completely dissolved. Then, the temperature was lowered to -77℃, and 800g of chloromethane, 456g of isobutylene, and 16g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -97℃. Then, 140g of chloromethane, 2.21g of sesquiethylaluminum chloride, and 0.0317g of HCl were mixed and aged at -92℃ for 44 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.3 hours. Finally, 42g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0106] Example 6

[0107] (1) Preparation of polymeric 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, 1800g of hexane, 880g of ethylene bromo, 120g of allyl bromide, and 6.5g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 66℃, 2.2g of BPO was added, and the reaction was carried out for 4.5 hours. Then, 45g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 55 minutes until no free monomers were present. After the reaction was completed, the mixture was washed and dried to obtain the macromolecular brominating agent.

[0109] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged four times. Then, 2800g of cyclohexane, 120g of isoprene, and 4.6g of THF were added to the polymerization reactor in sequence. The temperature was raised to 59℃, and 21.3 mmol of n-butyllithium was added to start the reaction for 57 min. Then, 210g of styrene and 120g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 67℃. The reaction was carried out for 65 min to form -IR-SBR- segments. Finally, 550g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 79℃. The reaction was carried out for 85 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 45600, Mw / Mn is 2.96).

[0110] (2) Preparation of anionic brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged four times. Then, 500g of chloromethane, 500g of cyclohexane, and 29g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 58 minutes until completely dissolved. Then, the temperature was lowered to -79℃, and 900g of chloromethane, 453g of isobutylene, and 18g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -98℃. Then, 145g of chloromethane, 2.45g of sesquiethylaluminum chloride, and 0.0426g of HCl were mixed and aged at -94℃ for 47 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 4.7 hours. Finally, 46g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0111] Example 7

[0112] (1) Preparation of polymeric 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, 2000g of hexane, 900g of ethylene bromine, 100g of allyl bromide, and 7.0g of tert-dodecyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 70℃, 3.0g of BPO was added, and the reaction was carried out for 5.0hr. Then, 50g of 1,3-butadiene was added to the polymerization 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] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged four times. Then, 3000g of cyclohexane, 100g of isoprene, and 5.0g of THF were added to the polymerization reactor in sequence. The temperature was raised to 60℃, and 23.5 mmol of n-butyllithium was added to start the reaction for 60 min. Next, 200g of styrene and 100g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 70℃. The reaction was carried out for 70 min to form -IR-SBR- segments. Finally, 600g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 80℃. The reaction was carried out for 90 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 49600, Mw / Mn is 3.14).

[0115] (2) Preparation of anionic brominated branched butyl rubber: First, in a jacketed 4L stainless steel reactor, nitrogen was purged five times. Then, 300g of chloromethane, 700g of cyclohexane, and 30g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 60 minutes until completely dissolved. Then, the temperature was lowered to -80℃, and 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, 2.68g of sesquiethylaluminum chloride, and 0.0517g of HCl were mixed and aged at -95℃ for 50 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 5.0 hours. Finally, 50g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0116] Example 8

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

[0118] Preparation of macromolecular brominating agent: First, in a 15L stainless steel reactor with a jacket, nitrogen gas was purged twice. Then, 1000g of octane, 805g of ethylene bromine, 195g of allyl bromide, and 4.3g of tert-decyl mercaptan were added to the reactor in sequence. The mixture was stirred and heated. When the reactor temperature reached 50℃, 0.8g of dicumyl peroxide was added, and the reaction was carried out for 3.0 hours. Then, 22g 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 brominating agent.

[0119] b. Preparation of the high molecular weight brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged twice. Then, 2000g of octane, 105g of isoprene, and 3.2g of diethyl ether were added to the polymerization reactor in sequence. The temperature was raised to 50℃, and 15.1 mmol of methyl butyllithium was added to start the reaction for 40 min. Then, 290g of styrene and 110g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 60℃. The reaction was carried out for 50 min to form -IR-SBR- segments. Finally, 500g of macromolecular brominated agent was added to the polymerization reactor, and the temperature was raised to 70℃. The reaction was carried out for 60 min until no free monomers were present. The solution was wet coagulated and dried to obtain the high molecular weight brominated grafting agent (Mn is 32100, Mw / Mn is 2.31).

[0120] (2) Preparation of anionic brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen was purged three times. Then, 360g of tetrachloropropane, 140g of hexane, and 21g of high-molecular-weight brominated grafting agent were added to the polymerization reactor and stirred for 40 minutes until completely dissolved. Then, the temperature was lowered to -70℃, and 500g of tetrachloropropane, 470g of isobutylene, and 10g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -90℃. Then, 100g of dichloromethane, 1.75g ​​of dimethylaluminum chloride, and 0.019g of HCl were mixed and aged at -86℃ for 30 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.2 hours. Finally, 27g of ethanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0121] Comparative Example 1

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

[0123] Preparation of macromolecular brominating agent: Other conditions are the same as in Example 1, except that allyl bromide is not added during the preparation of macromolecular brominating agent. Specifically: First, in a 15L stainless steel reactor with a jacket, nitrogen gas is purged twice. Then, 1000g of hexane, 800g of ethylene bromo, and 4.0g of tert-dodecyl mercaptan are added to the reactor in sequence. The mixture is stirred and heated. When the reactor temperature reaches 50°C, 0.6g of BPO is added and the reaction is carried out for 3.0 hours. Then, 20g of 1,3-butadiene is added to the polymerization reactor for end-capping. The reaction is carried out for 40 minutes until no free monomers are present. After the reaction is completed, the mixture is washed and dried to obtain macromolecular brominating agent-1.

[0124] b. Preparation of the high molecular weight brominated grafting agent: Other conditions are the same as in Example 1, except that no macromolecular brominizing agent is added during the synthesis process. Instead, macromolecular brominizing agent-1 is added in an amount of 500g. That is, first, in a 15L stainless steel reactor with a jacket, argon gas is purged twice, and then 2000g of cyclohexane, 100g of isoprene, and 3.0g of... are added sequentially to the polymerization reactor. THF was heated to 50°C, and 14.7 mmol of n-butyllithium was added to initiate a reaction for 40 min. Then, 300 g of styrene and 100 g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 60°C, and the reaction was carried out for 50 min to form -IR-SBR- segments. Finally, 500 g of macromolecular brominating agent-1 was added to the polymerization reactor, and the temperature was raised to 70°C, and the reaction was carried out for 60 min until no free monomers were present. The gel solution was wet-coagulated and dried to obtain macromolecular bromination grafting agent-1 (Mn is 29000, Mw / Mn is 2.18).

[0125] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 1, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-1 is added, with an addition amount of 20g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 350g of chloromethane, 150g of cyclohexane, and 20g of polymeric brominated grafting agent-1 are added to the polymerization reactor. The mixture is stirred and dissolved for 40min until it is completely dissolved. Then, when the temperature is lowered to -70℃, 500g of chloromethane, 470g 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, 1.75g ​​of sesquiethylaluminum chloride, and HCl are added. 0.019g of the mixture was aged at -86℃ for 30 minutes, then added to the polymerization system and stirred for 3.0 hours. Finally, 27g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0126] Comparative Example 2

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

[0128] Preparation of macromolecular brominating agent: Other conditions are the same as in Example 2, except that the amount of ethylene bromide added in the preparation of macromolecular brominating agent is 500 g. That is: First, in a 15L stainless steel reactor with a jacket, nitrogen gas is purged three times. Then, 1200 g of hexane, 500 g of ethylene bromide, 190 g of allyl bromide, and 4.5 g of tert-dodecyl mercaptan are added to the reactor in sequence. The mixture is stirred and heated. When the reactor temperature reaches 53°C, 0.9 g of BPO is added and the reaction is carried out for 3.4 hours. Then, 24 g of 1,3-butadiene is added to the polymerization reactor for end-capping. The reaction is carried out for 43 minutes until no free monomers are present. After the reaction is completed, the mixture is washed and dried to obtain macromolecular brominating agent-2.

[0129] b. Preparation of the high molecular weight brominated grafting agent: Other conditions are the same as in Example 2, except that no macromolecular brominizing agent is added during the synthesis process. Instead, macromolecular brominizing agent-2 is added in an amount of 600g. That is, first, in a 15L stainless steel reactor with a jacket, argon gas is purged three times, and then 2100g of cyclohexane, 110g of isoprene, and 3.2g of... are added sequentially to the polymerization reactor. THF was heated to 52°C, and 15.6 mmol of n-butyllithium was added to initiate a reaction for 43 min. Then, 280 g of styrene and 110 g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 62°C, and the reaction was carried out for 53 min to form -IR-SBR- segments. Finally, 600 g of macromolecular brominated agent-2 was added to the polymerization reactor, and the temperature was raised to 71°C, and the reaction was carried out for 65 min until no free monomers were present. The gel solution was wet-coagulated and dried to obtain high molecular weight brominated grafting agent-2 (Mn is 31200, Mw / Mn is 2.23).

[0130] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 2, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-2 is added, with an addition amount of 22g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 300g of chloromethane, 200g of cyclohexane, and 22g of polymeric brominated grafting agent-2 are added to the polymerization reactor. The mixture is stirred and dissolved for 43min until it is completely dissolved. Then, when the temperature is lowered to -72℃, 600g of chloromethane, 467g of isobutylene, and 11g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -91℃. Then, 110g of chloromethane, 1.83g of sesquiethylaluminum chloride, and HCl are added. 0.021g of the mixture was aged at -87℃ for 34 minutes, then added to the polymerization system and stirred for 3.3 hours. Finally, 30g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0131] Comparative Example 3

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

[0133] Preparation of macromolecular brominating agent: Other conditions are the same as in Example 3, except that 1,3-butadiene is not added during the preparation of macromolecular brominating agent. Specifically: First, nitrogen gas is purged three times in a 15L stainless steel reactor with a jacket. Then, 1400g of hexane, 830g of ethylene bromine, 170g of allyl bromide, 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 56°C, 1.0g of BPO is added, and the reaction is carried out for 3.8 hours. After the reaction is completed, the mixture is washed and dried to obtain macromolecular brominating agent-3.

[0134] b. Preparation of the high molecular weight brominated grafting agent: Other conditions are the same as in Example 3, except that: no macromolecular brominizing agent is added during the synthesis process, but macromolecular brominizing agent-3 is added, with an amount of 410g, that is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged three times, and then 2300g of cyclohexane, 130g of isoprene, and 3.7g of... are added sequentially to the polymerization reactor. THF was heated to 54°C, and 16.8 mmol of n-butyllithium was added to initiate a reaction for 48 min. Then, 260 g of styrene and 200 g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 63°C, and the reaction was carried out for 57 min to form -IR-SBR-- segments. Finally, 410 g of macromolecular brominated grafting agent-3 was added to the polymerization reactor, and the temperature was raised to 73°C, and the reaction was carried out for 70 min until no free monomers were present. The gel solution was wet coagulated and dried to obtain high molecular weight brominated grafting agent-3 (Mn is 35200, Mw / Mn is 2.35).

[0135] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 3, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-3 is added, with an addition amount of 24g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 260g of chloromethane, 240g of cyclohexane, and 24g of polymeric brominated grafting agent-3 are added to the polymerization reactor. The mixture is stirred and dissolved for 47min until it is completely dissolved. Then, when the temperature is lowered to -74℃, 700g of chloromethane, 463g of isobutylene, and 13g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -93℃. Then, 120g of chloromethane, 1.92g of sesquiethylaluminum chloride, and HCl are added. 0.025g of the mixture was aged at -89℃ for 39 minutes, then added to the polymerization system and stirred for 3.7 hours. Finally, 35g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0136] Comparative Example 4

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

[0138] Preparation of macromolecular brominating agents: Same as in Example 4.

[0139] b. Preparation of the high molecular weight brominated grafting agent: Other conditions are the same as in Example 4, except that no macromolecular brominating agent is added during the preparation of the high molecular weight brominated grafting agent. Instead, ethylene bromide is added directly in an amount of 420g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 2500g of cyclohexane, 150g of isoprene, and 4.0g of THF are added sequentially to the polymerization reactor. The temperature is raised to 55°C, and 18.3 mmol of n-butyllithium is added to initiate a reaction for 50 min. Next, 250g of styrene and 180g of 1,3-butadiene are added to the polymerization reactor, and the temperature is raised to 65°C. The reaction is continued for 60 min to form -IR-SBR- segments. Finally, 420g of ethylene bromide is added to the polymerization reactor, and the temperature is raised to 75°C. The reaction continues for 75 min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the high molecular weight brominated grafting agent-4 (Mn is 28300, Mw / Mn). (It is 1.57).

[0140] (2) Preparation of brominated branched butyl rubber: Other conditions are the same as in Example 4, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-4 is added, with an addition amount of 26g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 700g of chloromethane, 300g of cyclohexane, and 26g of polymeric brominated grafting agent-4 are added to the polymerization reactor. The mixture is stirred and dissolved for 50min until it is completely dissolved. Then, when the temperature is lowered to -75℃, 760g of chloromethane, 459g of isobutylene, and 15g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -95℃. Then, 130g of chloromethane, 2.02g of sesquiethylaluminum chloride, and HCl are added. 0.027g of the mixture was aged at -90℃ for 41 min, then added to the polymerization system and stirred for 4.0 hr. Finally, 40g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0141] Comparative Example 5

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

[0143] Other conditions were the same as in Example 5, except that instead of a macromolecular brominating agent, a small molecule brominating agent, allyl bromide, was added during the preparation of the polymeric brominated grafting agent. The amount added was 480g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2600g of cyclohexane, 160g of isoprene, and 4.3g of THF were added sequentially to the polymerization reactor. The temperature was raised to 57°C, and 19.1 mmol of n-butyllithium was added to initiate a reaction for 54 min. Next, 220g of styrene and 140g of 1,3-butadiene were added to the polymerization reactor, and the temperature was raised to 66°C. The reaction was carried out for 62 min to form IR-SBR-segments. Finally, 480g of allyl bromide was added to the polymerization reactor, and the temperature was raised to 77°C. The reaction was carried out for 80 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain polymeric brominated grafting agent-5 (Mn is 32000, Mw / Mn). (It is 1.95).

[0144] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 5, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-5 is added, with an addition amount of 28g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 600g of chloromethane, 400g of cyclohexane, and 28g of polymeric brominated grafting agent-5 are added to the polymerization reactor. The mixture is stirred and dissolved for 55min until it is completely dissolved. Then, when the temperature is lowered to -77℃, 800g of chloromethane, 456g of isobutylene, and 16g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -97℃. Then, 140g of chloromethane, 2.21g of sesquiethylaluminum chloride, and HCl are added. 0.0317g of the mixture was aged at -92℃ for 44 min, then added to the polymerization system and stirred for 4.3 hr. Finally, 42g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0145] Comparative Example 6

[0146] (1) Preparation of polymeric brominated grafting agent:

[0147] Preparation of macromolecular brominating agents: Same as in Example 6.

[0148] b. Preparation of the high molecular weight brominated grafting agent: Same as in Example 6.

[0149] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 6, except that the amount of polymer brominated grafting agent added during the preparation of brominated branched butyl rubber is 10 g, that is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 4 times, and 500 g of chloromethane, 500 g of cyclohexane, and 10 g of polymer brominated grafting agent are added to the polymerization reactor and stirred to dissolve for 58 min until completely dissolved; then, when the temperature is lowered to -79℃, 900 g of chloromethane, 453 g of isobutylene, and 18 g of isoprene are added in sequence and stirred until the temperature of the polymerization system drops to -98℃, and then 145 g of chloromethane, 2.45 g of sesquiethylaluminum chloride, and HCl are added. 0.0426g of the mixture was aged at -94℃ for 47 min, then added to the polymerization system and stirred for 4.7 hr. Finally, 46g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0150] Comparative Example 7

[0151] (1) Preparation of polymeric brominated grafting agent:

[0152] Preparation of macromolecular brominating agents: Same as in Example 7.

[0153] b. Preparation of the polymeric brominated grafting agent: Other conditions are the same as in Example 7, except that styrene is not added during the preparation of the polymeric brominated grafting agent. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged four times. Then, 3000g of cyclohexane, 100g of isoprene, and 5.0g of THF are added to the polymerization reactor in sequence. The temperature is raised to 60°C, and 23.5 mmol of n-butyllithium is added to start the reaction for 60 min. Then, 100g of 1,3-butadiene is added to the polymerization reactor, the temperature is raised to 70°C, and the reaction is carried out for 70 min to form -IR-BR- segments. Finally, 600g of macromolecular brominated agent is added to the polymerization reactor, the temperature is raised to 80°C, and the reaction is carried out for 90 min until no free monomers are present. The solution is wet-coagulated and dried to obtain polymeric brominated grafting agent-6 (Mn is 43200, Mw / Mn is 2.68).

[0154] (2) Preparation of anionic brominated branched butyl rubber: Other conditions are the same as in Example 7, except that: no polymeric brominated grafting agent is added during the preparation of brominated branched butyl rubber, but polymeric brominated grafting agent-6 is added, with an addition amount of 30g, that is: firstly, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 300g of chloromethane, 700g of cyclohexane, and 30g of polymeric brominated grafting agent-6 are added to the polymerization reactor, and stirred and dissolved for 60min until completely dissolved; then, when the temperature is lowered to -80℃, 1000g of chloromethane, 450g of isobutylene, and 20g of isoprene are added in sequence, and stirred and mixed until the temperature of the polymerization system drops to -100℃, and then 150g of chloromethane and 2.68g of sesquiethylaluminum chloride are added. 0.0517 g of HCl and 0.0517 g of HCl were mixed and aged at -95℃ for 50 min, then added to the polymerization system and stirred for 5.0 hr. Finally, 50 g of methanol was added, the mixture was discharged, coagulated, washed, and dried to obtain the brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test properties are shown in Table 1.

[0155] Table 1 Properties of anionic brominated branched butyl rubber

[0156]

[0157] 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.

[0158] As shown in Table 1, the 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.

[0159] 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 anionic brominated branched butyl rubber, characterized in that, The preparation method includes the following steps: S1: Add the polymeric brominated grafting agent to the mixed solvent and stir thoroughly until the polymeric brominated grafting agent is completely dissolved to obtain a mixed solution; the mass ratio of the mixed solvent to the polymeric brominated grafting agent is 100~200:4~6; 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 anionic brominated branched butyl rubber. The preparation method of the polymer brominated grafting agent specifically includes the following steps: Preparation of macromolecular brominating agent: Taking 100 parts by total mass of ethylene bromide and allyl halide as the base, firstly, add 100-200 parts of solvent, 80-90 parts of ethylene bromide, 10-20 parts of allyl halide, and 0.4-0.7 parts of molecular weight regulator sequentially to the reaction vessel after inert gas purging. Stir and mix, heat, and when the reaction vessel temperature reaches 50-70℃, add 0.05-0.3 parts of the first initiator. React for 3.0-5.0 h until the ethylene bromide monomer conversion rate reaches 100%. Then, add 2-5 parts of butadiene to the reaction vessel for end-capping and react for 40-60 min until no free monomers are present. After the reaction is completed, wash and dry to obtain the macromolecular brominating agent. b. Preparation of the high-molecular-weight brominated grafting agent: Based on 100% of the total mass of the reacting monomers, first, add 200 wt%–300 wt% solvent, 10 wt%–20 wt% isoprene, and 0.3 wt%–0.5 wt% structure modifier sequentially to the reactor after inert gas purging. After heating to 50–60 °C, add the second initiator and react for 40–60 min. Then, add 20 wt%–30 wt% styrene, 10 wt%–20 wt% butadiene, and 0.05 wt%–0.2 wt% structure modifier to the reactor. The temperature is increased to 60-70℃ and reacted for 50-70 minutes to form -IR-SBR- segments, where IR is the isoprene homopolymer block and SBR is the styrene-butadiene random copolymer block. Finally, 30wt%-60wt% of macromolecular brominating agent is added to the reactor, the temperature is increased to 70-80℃, and the reaction is carried out for 60-90 minutes until no free monomers are present. After the reaction is completed, the polymeric bromination grafting agent is obtained by wet coagulation and drying. The number-average molecular weight (Mn) of the brominated grafting agent is 30,000 to 50,000, and the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) is 2.27 to 3.

14.

2. The method for preparing anionic brominated branched butyl rubber according to claim 1, characterized in that, In step S1, 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 anionic brominated branched butyl rubber according to claim 1, characterized in that, In step S2, the temperature is cooled to -70℃ to -80℃; the temperature is then cooled again to -100℃ to -90℃.

4. The method for preparing anionic brominated branched butyl rubber according to claim 1, characterized in that, In step S2, the mass ratio of the diluent, isobutylene, and isoprene is 100~200:90~94:2~4.

5. The method for preparing anionic 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 20~30:0.05~0.5:5~10.

6. The method for preparing anionic brominated branched butyl rubber according to claim 1, characterized in that, The molecular weight regulator is at least one of tert-decanethiol, tert-dodecanethiol, tert-tetradecanethiol, and tert-hexadecanethiol; The allyl halide is at least one selected from allyl bromide, 2-methyl-1-allyl bromide, 2-ethyl-1-allyl bromide, 2-propyl-1-allyl bromide, and 2-butyl-1-allyl bromide; 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, 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 anionic brominated branched butyl rubber according to claim 1 or 2, characterized in that, The solvent is selected from at least one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene.

8. The method for preparing anionic 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, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane.

9. The method for preparing anionic 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, H2CO3, H3PO4, and HNO3; the molar ratio of the protic acid to the alkyl aluminum halide is 0.01:1 to 0.1:

1.

10. The method for preparing anionic 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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