A grafting agent for brominated star-branched butyl rubber and a preparation method thereof, and a preparation method of brominated star-branched butyl rubber

Abstract

This invention discloses a grafting agent and preparation method for brominated star-branched butyl rubber, as well as a method for preparing brominated star-branched butyl rubber. The brominated grafting agent is a three-armed star-shaped block copolymer with a highly isotactic molecular chain structure containing polyester groups and bromine atoms. This functional polymeric damping three-armed brominated grafting agent utilizes the superposition of "group effect" and "structural effect" to greatly improve the effective damping temperature range and damping performance of brominated branched butyl rubber. The butyl rubber obtained using this brominated grafting agent has an effective damping temperature range (tanδ≥0.3) that meets the requirements for use in the range of -85 to 96℃, and the maximum damping factor tanδ... max Brominated star-branched butyl rubber with a wide temperature range and high damping of ≥2.7 can well meet the requirements for the use of wide temperature range damping materials.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of rubber, in particular to a grafting agent for brominated star-branched butyl rubber and a preparation method thereof, and a preparation method of the brominated star-branched butyl rubber. BACKGROUND

[0002] With the rapid development of modern science and technology, mechanical equipment tends to be high frequency and high speed in many fields such as high-speed rail, aerospace, naval ships, mechanical engineering, automobiles and electronic appliances, which brings convenience to daily production and life but also causes a series of problems such as high-frequency vibration and noise. These problems not only accelerate the fatigue damage of mechanical structure materials and shorten their service life, but also pose an increasingly serious threat to people's life and property safety. Therefore, developing high-performance damping materials with excellent performance and improving the application of damping and shock absorption is of great importance to improve the operating environment of machinery and the health and safety of human beings.

[0003] Brominated butyl rubber (BIIR) is obtained by introducing bromine atoms into the molecular chain of butyl rubber (IIR) through electrophilic substitution reaction under the action of bromine. Compared with IIR, BIIR has good adhesion, fast curing speed, good thermal stability and corrosion resistance, and can be used in extreme environments such as strong corrosion or high temperature. In addition, due to the introduction of bromine atoms, the polarity of the molecular chain increases, the relaxation resistance of the chain segment increases, and the internal friction is large. BIIR has excellent damping performance, and is one of the most widely used basic damping rubbers.

[0004] At present, in actual application, it is often required to have damping function in the range of-50 DEG C to +50 DEG C. However, the effective damping function zone (damping factor tan delta > 0.3) of the existing brominated butyl rubber is mainly concentrated in the low temperature part, and the damping value is low above 15 DEG C, which cannot meet the use requirements of the wide temperature range damping material. Therefore, how to widen the effective damping function zone of butyl rubber above room temperature is one of the research hotspots of rubber damping materials at present.

[0005] In the prior art, the methods for widening the temperature range of butyl rubber and improving its damping performance mainly include blending, copolymerization, interpenetrating polymer network, and adding small-molecule organic functional damping agents. For example, Chinese Patent Document CN112574333A provides a bromination process for star-branched butyl rubber, which includes: a) dissolving the star-branched butyl rubber in an aliphatic hydrocarbon to obtain a rubber solution; b) mixing the rubber solution with a branched agent capturing agent, ethanol, to obtain a mixed solution; c) adding an oxidizing agent, hydrogen peroxide, and a bromination agent, Br2, to the mixed solution, and the molar ratio of bromine element to unsaturated double bonds in the star-branched butyl rubber is (0.75-2):1, to carry out bromination reaction, and finally neutralization and product recovery to obtain brominated star-branched butyl rubber. This process can dissolve the residual branched agent in the star-branched butyl rubber before bromination, preventing it from combining with the HBr byproduct produced during the bromination process, thereby improving the neutralization efficiency and inhibiting the isomerization transition of Type II secondary structures to Type III primary structures.

[0006] Chinese Patent Document CN102775659A discloses a preparation method for a wide-temperature-range, wide-frequency, high-damping rubber material, which includes the following steps: mixing epoxidized natural rubber, a softening agent, a filler, an acidified multi-walled carbon nanotube damping enhancer, a phenolic resin vulcanizing agent, and a vulcanizing agent at 40-150°C to form a rubber compound, allowing it to stand, and vulcanizing it under certain conditions to obtain a wide-temperature-range, wide-frequency, high-damping rubber material with an effective damping temperature range of up to 150°C and an effective damping frequency range of 10 -5 ~10 8 Hz.

[0007] Chinese Patent Document CN106749816A discloses a preparation method for brominated butyl rubber. First, the butyl rubber is dissolved in a normal alkane, and then a specific organic bromide such as phenyltrimethylammonium tribromide, benzyltrimethylammonium tribromide, or dibromoisocyanuric acid is used as a bromination agent, and Br2 or HBr is used as a bromination promoter to carry out a bromination reaction in a solvent, obtaining brominated butyl rubber. This method inhibits the molecular rearrangement of secondary bromine in brominated butyl rubber to form primary bromine, increasing the content of secondary bromine structures in brominated butyl rubber.

[0008] Chinese Patent Document CN113969031A discloses a high-performance damping rubber and a preparation method thereof. The high-performance damping rubber is obtained by blending and polymerizing a first precursor and a second precursor. The first precursor has a molecular chain with a cationic group, and the second precursor has a molecular chain with an anionic group. The molar ratio of cationic groups to anionic groups in the rubber is 1:1. The prepared high-performance damping rubber has a breaking strength of 5-20 MPa, an elongation at break of 200%-300%, a high repair efficiency of up to 90%, and a wide damping temperature range and high repair efficiency with a repair temperature of 20-100°C.

[0009] Chinese patent document CN103113682A discloses a wide temperature range high damping material for electronic products and a preparation method thereof. A supramolecular network structure is formed through the interaction between non-polar butyl rubber and brominated p-t-octylphenol formaldehyde resin and polar small molecule hindered phenol A060, and the temperature range can reach -60-100°C.

[0010] Chinese patent document CN102229724A discloses a method for widening the damping temperature range by blending rubber with rubber or rubber with plastic to form a micro-phase separation structure.

[0011] Chinese patent document CN113493553A discloses a preparation method of high-branched butyl rubber. First, a jacketed reactor is charged with solvent, isoprene, structure regulator and initiator in sequence, heated to 45-55°C and reacted, then the polymerization reactor is charged with solvent, styrene, butadiene and structure regulator in sequence, heated to 60-70°C and reacted, then the polymerization reactor is charged with styrene and structure regulator, heated to 70-80°C and reacted, then the polymerization reactor is charged with butadiene for end-capping, and the reaction is continued until no free monomer exists. Finally, the temperature is raised to 85-90°C, and a coupling agent is added for coupling reaction. After the reaction is completed, the coupled reaction mixture is treated with water, and the glue solution is subjected to wet coagulation and drying to obtain a grafting agent. The grafting agent is reacted with isobutene and isoprene to obtain high-branched butyl rubber product.

[0012] Chinese patent document CN1266193C discloses a butyl rubber / poly(meth)acrylate interpenetrating polymer network damping material. The poly(meth)acrylate can significantly move the effective damping function zone of butyl rubber to room temperature through the physical interlocking action between the interpenetrating polymer network and butyl rubber. The maximum damping value tanδ max of the butyl rubber / poly(meth)acrylate interpenetrating polymer network damping material can reach 1.43 at a test frequency of 125 Hz in a cantilever mode. The temperature range at which tanδ max occurs is 10-40°C. The forced mutual compatibility effect of the double network widens the damping function zone of butyl rubber, and the temperature range can reach 110°C, and a very wide damping platform zone is formed, which can ensure that the butyl rubber / poly(meth)acrylate interpenetrating polymer network damping material effectively absorbs vibration in a wide temperature range.

[0013] Tao Gang et al. (Polymer Materials Science and Engineering, 2013, 29(11): 114-118) disclose that a CIIR / NBR blend with a mass ratio of 80 / 20 can be prepared by adding 30 phr of chloroprene rubber (CR), and the temperature range is from -66°C to 67°C, and the frequency range is from 10 -3 Hz to 10 15CIIR / NBR / CR ternary blended wide temperature range wide frequency range high damping rubber material with tan delta greater than or equal to 0.3 above 1 Hz.

[0014] Liao Mingyi et al. (Journal of Dalian Maritime University, 2008, 34(2): 83-86) discloses a method for improving the damping performance of butyl rubber (IIR) by using a step-by-step method. IIR is used as polymer network I, and poly(styrene-methyl methacrylate) [P(St-MMA)] is used as polymer network II. An interpenetrating polymer network [IIR / P(St-MMA)] of butyl rubber / poly(styrene-methyl methacrylate) is prepared by graft polymerization, and a wide temperature range high damping butyl rubber material is prepared.

[0015] In the above prior art, although the effective damping temperature range of the rubber can be widened to some extent and the damping performance of the rubber can be improved by adding functional damping agents, blending methods, copolymerization methods and interpenetrating network polymers, the actual application requirements of wide temperature range high damping materials cannot be met, and these methods have certain limitations: the mechanical properties of the modified materials are reduced.

[0016] Therefore, how to widen the effective damping temperature range of the rubber, improve the damping performance of the rubber, meet the actual application requirements of butyl rubber, and maintain excellent mechanical properties is a technical problem to be solved in the field of butyl rubber materials. SUMMARY

[0017] The purpose of the present application is to solve the problems of narrow effective damping temperature range, poor damping performance and mechanical properties of the existing modified butyl rubber, and to provide a grafting agent for brominated star-branched butyl rubber. The brominated star-branched butyl rubber prepared by polymerization of the grafting agent with isobutene and isoprene has the advantages of wide temperature range, high damping, excellent mechanical properties, good air tightness and other advantages. The excellent comprehensive performance can meet the actual application requirements of wide temperature range high damping materials in the fields of high-speed rail, ships and various mechanical and electrical devices.

[0018] To achieve the above purpose, the present application provides a grafting agent for brominated star-branched butyl rubber, which has the following formula 1 structure:

[0019]

[0020] wherein I is a small molecule isoprene or 1,3-butadiene segment; BR is a 1,3-butadiene homopolymer block; A is a 4-vinyl-1,2-benzenedicarboxylic acid diester or a homopolymer block of its isomer; D is a trans-2-methyl-1,4-dibromo-2-butene homopolymer block; n is the number of repeating units, n≥1.

[0021] The number average molecular weight (Mn) of the grafting agent of the brominated star branched butyl rubber is 60000-70000, and the bromine content is 4.12wt%-5.26wt%.

[0022] Optionally, in the grafting agent of the brominated star branched butyl rubber provided by the present application, the molecular weight distribution (Mw / Mn) of the grafting agent of the brominated star branched butyl rubber is 4.51-5.12.

[0023] Optionally, in the grafting agent of the brominated star branched butyl rubber provided by the present application, the 4-vinyl-1,2-benzenedicarboxylic acid diester or its isomer is selected from any one of 4-vinyl-1,2-benzenedicarboxylic acid dimethyl ester, 4-vinyl-1,2-benzenedicarboxylic acid diethyl ester, 4-vinyl-1,2-benzenedicarboxylic acid dipropyl ester, 4-vinyl-1,2-benzenedicarboxylic acid dibutyl ester, 4-vinyl-1,2-benzenedicarboxylic acid diisobutyl ester, 4-vinyl-1,2-benzenedicarboxylic acid diisoamyl ester, 4-vinyl-1,2-benzenedicarboxylic acid dihexyl ester, 4-vinyl-1,2-benzenedicarboxylic acid diheptyl ester, 4-vinyl-1,2-benzenedicarboxylic acid dioctyl ester, 4-vinyl-1,3-benzenedicarboxylic acid diethyl ester, etc.; preferably 4-vinyl-1,2-benzenedicarboxylic acid diethyl ester.

[0024] The present application also provides a preparation method of the above-mentioned grafting agent of the brominated star branched butyl rubber, comprising the following steps:

[0025] S1, in anhydrous and anaerobic environment, mixing the structure regulator, 4-vinyl-1,2-benzenedicarboxylic acid diester or its isomer in a hydrocarbon solvent, heating to 60-70℃, and then adding an initiator to perform a first anionic polymerization reaction;

[0026] S2, after the first anionic polymerization reaction is completed, adding trans-2-methyl-1,4-dibromo-2-butene and a structure regulator to perform a second anionic polymerization reaction;

[0027] S3, after the second anionic polymerization reaction is completed, adding 1,3-butadiene and a structure regulator to perform a third anionic polymerization reaction;

[0028] S4, after the third anionic polymerization reaction is completed, heating the system to 80-90℃, adding a coupling agent to perform a coupling reaction, and then adding an end-capping agent to perform end-capping until there is no free monomer, and then the obtained glue solution is subjected to wet coagulation and drying to obtain the grafting agent of the brominated star branched butyl rubber;

[0029] The coupling agent is 1,3,5-trichlorobenzene or 1,3,5-tribromobenzene, preferably 1,3,5-trichlorobenzene;

[0030] The end-capping agent is selected from isoprene or 1,3-butadiene.

[0031] The preparation method of the grafting agent of the brominated star branched butyl rubber is not limited in the amount of each material and the reaction time of each step. The amount of each material and the reaction time are adjusted to ensure that the number average molecular weight (Mn) of the finally prepared grafting agent of the brominated star branched butyl rubber is 60,000-70,000, and the bromine content is 4.12wt%-5.26wt%.

[0032] Optionally, in the preparation method of the grafting agent of the brominated star branched butyl rubber, the amount of each material and the reaction time of each step in the preparation process of the grafting agent recommended by the present application are as follows: taking the amount of the 4-vinyl-1,2-benzenedicarboxylic acid diester or its isomer as 100%, in step S1, the amount of the solvent is 200%-300%, the amount of the structure regulator is 0.3%-0.5%, and the time of the first anionic polymerization is 70-90 min.

[0033] In step S2, the amount of the trans-2-methyl-1,4-dibromo-2-butene is 30%-40%, the amount of the structure regulator is 0.2%-0.4%, and the time of the second anionic polymerization is 60-70 min; in step S3, the amount of the 1,3-butadiene is 15%-25%, the amount of the structure regulator is 0.1%-0.3%, and the time of the third anionic polymerization is 40-50 min.

[0034] In step S4, the amount of the end-capping agent is 1.0%-3.0%.

[0035] Optionally, in the preparation method of the grafting agent of the brominated star branched butyl rubber, the type of the initiator is not limited as long as the type of polymerization is anionic polymerization. The initiator recommended by the present application is RLi, wherein R is selected from C1-C20 linear or branched alkyl, C6-C12 substituted or unsubstituted aryl (substituted means that at least one H on the aryl is replaced by C1-C5 linear or branched alkyl); preferably, the initiator is selected from any one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium and dodecyl lithium, and more preferably n-butyllithium.

[0036] The structure regulator is a polar organic compound which produces a solvating effect in the polymerization system, and is used to regulate the reactivity ratio of 4-vinyl-1,2-benzene dicarboxylic diester, trans-2-methyl-1,4-dibromo-2-butene and 1,3-butadiene in the polymerization system, so that the three form a block copolymer. The structure regulator recommended in the present application is selected from any one of diethylene glycol dimethyl ether (DGE), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME) and triethylamine, and preferably tetrahydrofuran (THF).

[0037] Optionally, in the preparation method of the grafting agent of the brominated star branched butyl rubber provided by the present application, the amount of the initiator RLi is not specifically limited, and can be determined according to the molecular weight of the designed grafting agent, and then determined according to the conventional relationship between the addition amount of RLi and the target preparation weight of the polymer. For example, the addition amount of RLi can be determined by the following formula:

[0038]

[0039] wherein the total mass of the glue is the target preparation weight of the designed grafting agent, and the molecular weight refers to the molecular weight of the grafting agent.

[0040] Optionally, in the preparation method of the grafting agent of the brominated star branched butyl rubber provided by the present application, the amount of the coupling agent is determined according to the amount of the initiator, and the molar ratio of the coupling agent to RLi recommended in the present application is 1:1 to 10:1.

[0041] The present application also provides a preparation method of a brominated star branched butyl rubber, comprising the following steps:

[0042] A1, mixing and aging the diluent and the co-initiator at -100 to -90℃ for 40 to 50 min to obtain the co-initiator solution;

[0043] A2, dissolving the grafting agent in the mixed solvent in anhydrous and anaerobic environment, and then cooling to -85 to -75℃, then adding the diluent, isobutene and isoprene in sequence, stirring and mixing until the temperature of the polymerization system is reduced to -90 to -80℃, then adding the co-initiator solution to carry out cationic polymerization, after the cationic polymerization is completed, adding a termination agent, discharging and coagulating, washing, drying to obtain the brominated star branched butyl rubber;

[0044] wherein the grafting agent is the grafting agent of the brominated star branched butyl rubber described above or the grafting agent of the brominated star branched butyl rubber prepared by the preparation method of the grafting agent of the brominated star branched butyl rubber described above;

[0045] The amount of the grafting agent is 5% to 7% based on 100% of the amount of the isobutene.

[0046] The ratio of the use amount of each material in the preparation method of the above brominated star branched butyl rubber is not specifically limited, and can be adjusted according to the molecular weight of the brominated star branched butyl rubber designed in practice. The recommended ratio of the use amount of each material is as follows: taking the use amount of the isobutylene as 100%, in step A1, the use amount of the diluent is 10% to 20%, and the use amount of the co-initiator is 0.2% to 0.6%;

[0047] In step A2, the use amount of the mixed solvent is 100% to 200%, the use amount of the diluent is 100% to 200%, the use amount of the isoprene is 3% to 5%, and the use amount of the terminator is 3% to 5%.

[0048] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the time of the cationic polymerization reaction is not limited, and can be adjusted according to the use amount of the material and the polymerization rate, for example, the time of the cationic polymerization reaction can be limited to 5 to 7 hours.

[0049] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the diluent is a C1-C4 halogenated alkane, and the halogen atom in the halogenated alkane is selected from chlorine, bromine or fluorine; preferably, the diluent is any one of methyl chloride, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride and fluorobutane, and more preferably, the diluent is methyl chloride.

[0050] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the co-initiator is a mixture of an alkyl aluminum halide and a protonic acid; preferably, the molar ratio of the protonic acid to the alkyl aluminum halide is 0.01:1 to 0.1:1.

[0051] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the alkyl aluminum halide is selected from at least one of monochlorodiethylaluminum, monochlorodiisobutylaluminum, dichloromethylaluminum, hemiethylaluminum chloride, hemiisobutylaluminum chloride, dichloro-n-propylaluminum, dichloro-isopropylaluminum, dimethylaluminum chloride and ethylaluminum chloride, and preferably, the alkyl aluminum halide is hemiethylaluminum chloride.

[0052] The protonic acid is selected from any one of HCl, HF, HBr, H2SO4, H2CO3, H3PO4 and HNO3, and preferably, the protonic acid is HCl.

[0053] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the mixed solvent is a mixture of a diluent and a hydrocarbon solvent, and preferably, the volume ratio of the diluent to the hydrocarbon solvent is (7 to 3):(3 to 7).

[0054] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the terminating agent is selected from at least one of methanol, ethanol and butanol.

[0055] Optionally, in the preparation method of the brominated star branched butyl rubber provided by the present application, the effective damping temperature range of the brominated star branched butyl rubber is -85℃ to 96℃, and the maximum damping factor tanδmax is greater than or equal to 2.7. max

[0056] In the present application, the preparation processes of the brominated star branched butyl rubber and the grafting agent of the brominated star branched butyl rubber are both carried out in a hydrocarbon solvent, and the polymerization reactions involved are all carried out in an oxygen-free and water-free environment, preferably in an inert gas environment. The hydrocarbon solvent can be selected from linear alkanes, aromatic hydrocarbons, cycloalkanes and the like, preferably one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene and ethylbenzene, and more preferably cyclohexane.

[0057] Compared with the prior art, the present application has the following advantages:

[0058] 1. The brominated star branched butyl rubber grafting agent prepared by the present application combines phenyl groups, bromine atoms and polybasic ester groups on a macromolecular chain through anionic polymerization, and then grafts onto the main chain of butyl rubber through cationic polymerization to form an interpenetrating polymer network structure (IPN). The phenyl groups, bromine atoms and polybasic ester groups have the characteristics of large rigidity, large steric hindrance and strong polarity, which can produce a significant "synergistic effect" in widening the effective damping temperature range and damping property of the brominated branched butyl rubber, greatly widening the effective damping temperature range and damping property of the brominated branched butyl rubber. The wide temperature range, high damping brominated star branched butyl rubber with an effective damping temperature range (tanδ≥0.3) of -85℃ to 96℃ and a maximum damping factor tanδmax≥2.7 can well meet the use requirements of high-speed rails and large engineering machinery for wide temperature range, high damping rubber materials.

[0059] 2. The anionic polymerization of the brominated star branched butyl rubber grafting agent prepared by the present application makes the phenyl groups, bromine atoms and polybasic ester groups arranged regularly on the molecular chain with high isotacticity, thereby producing the superposition of "group effect" and "structure effect", and avoiding the problem of the decrease of the air tightness and mechanical properties of butyl rubber caused by the broadening of molecular weight distribution due to branching.

[0060] 3. The wide temperature range, high damping brominated branched butyl rubber prepared by the present application is generated by addition polymerization of the grafting agent, not ion substitution, which blocks the conditions for bromine structural isomerization and improves the stability of the effective damping temperature range and damping property of the brominated branched butyl rubber.

[0061] ​4. The preparation method of the wide-temperature-range high-damping brominated star-branched butyl rubber has the characteristics of green environmental protection, stable product quality, easy-to-obtain raw materials and convenient industrial production. DETAILED DESCRIPTION

[0062] The application will be described in detail below by examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the protection scope of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above content of the application.

[0063] The specific experimental steps or conditions are not specified in the examples, and can be performed according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments used are not specified by the manufacturer, and are all conventional reagent products that can be obtained by purchase.

[0064] I. Raw material sources:

[0065] Isobutene, isoprene, polymer grade Zhejiang Xinhui New Material Co., Ltd.

[0066] 1,3-Butadiene, polymer grade PetroChina Lanzhou Petrochemical Company

[0067] Trans-2-methyl-1,4-dibromo-2-butene, polymer grade, Wuhan Prolif Bio-technology Co., Ltd.

[0068] 4-Vinyl-1,2-benzenedicarboxylic acid diethyl ester, purity 98%, Xi'an Qi Yue Bio-technology Co., Ltd.

[0069] 4-Vinyl-1,3-benzenedicarboxylic acid diethyl ester, purity 98%, Xi'an Qi Yue Bio-technology Co., Ltd. n-Butyllithium, purity 98%, Nanjing Tonglian Chemical Co., Ltd.

[0070] 1,3,5-Trichlorobenzene, purity 99%, Yangzhou Haichen Chemical Co., Ltd.

[0071] Hemisemic ethyl aluminum chloride, purity 98%, Bailingwei Technology Co., Ltd.

[0072] Other reagents are all commercially available industrial products

[0073] II. Analysis and test method:

[0074] Determination of molecular weight and distribution: determined by 2414 gel permeation chromatograph (GPC) produced by Waters Company of the United States. Polystyrene standard sample is used as a correction curve, the mobile phase is tetrahydrofuran, the column temperature is 40℃, the sample concentration is 1mg / ml, the injection amount is 50μL, the elution time is 40min, and the flow rate is 1ml·min -1 .

[0075] Bromine content determination: 10 mg sample was weighed and thermally degraded in a Q600 TG / DTG thermal gravimetric analyzer with a heating rate of 10 °C / min in a nitrogen atmosphere with a flow rate of 50 mL / min. The first stage of thermal degradation was the debromination of the bromine-containing units in the sample to form HBr, and the bromine content (X) in the sample was then calculated from the percentage content of the removed HBr. The calculation formula is as follows:

[0076]

[0077] In the formula, Y is the percentage content of the sample at 220 °C; 79.904 is the relative atomic mass of bromine; and 1.008 is the relative atomic mass of hydrogen.

[0078] Determination of Mooney stress relaxation: A high-iron GT-7080S2 Mooney viscometer was used to determine the Mooney viscosity at 125 °C (1+8) according to the method of GB / T1232.1-2000. The determination of stress relaxation was carried out after the Mooney viscosity test, and the torque was stopped quickly (within 0.1 s) and the decay of the Mooney viscosity value with time was recorded. The torque at the time when the rotor was stopped (within 0.1 s) was set as 100%, and the stress relaxation behavior of the rubber was expressed by t80 [the time used for the torque to decay by 80% (remaining 20%)] and X30 [the percentage of torque remaining after the rotor was stopped for 30 s].

[0079] Dynamic mechanical analysis (DMA): The determination was carried out on a dynamic mechanical analyzer (DMA) 242C of Netzsch, Germany, in a tensile mode. The sample size was 10 mm in length, 6 mm in width, and 2 mm in thickness. The temperature range was -90 °C to 100 °C, the heating rate was 3 °C / min, and the data at a frequency of 10 Hz were selected for analysis.

[0080] Determination of air tightness: The air permeation number was determined according to ISO 2782:1995 using an automatic air tightness tester. The test gas was N2, the test temperature was 23 °C, and the test sample was a 8 cm diameter circular sheet with a thickness of 1 mm.

[0081] Tensile strength: The method was in accordance with the execution standard GB / T528-2009.

[0082] Example 1

[0083] The present embodiment provides a brominated star-branched butyl rubber, and the preparation method is as follows:

[0084] (1) Preparation of the grafting agent of the brominated star-branched butyl rubber:

[0085] Firstly, in a 15L jacketed stainless steel reactor, the reactor was purged with argon for 3 times, then 2000g cyclohexane, 1000g 4-vinyl-1,2-phthalic acid diethyl ester, 3.0g THF were added into the reactor, then the temperature was raised to 60℃, and then 30.9mmol n-butyllithium was added to start the reaction for 70min; secondly, 300g trans-2-methyl-1,4-dibromo-2-butene, 2.0g THF were added into the reactor, and the reaction was carried out for 60min; then 150g 1,3-butadiene, 1.0g THF were added into the reactor, and the reaction was carried out for 40min; the temperature was raised to 80℃, and then 30.9mmol coupling agent 1,3,5-trichlorobenzene was added to carry out the coupling reaction for 80min; then 10g isoprene was added into the reactor to carry out the end-capping reaction for 20min until no free monomer existed, and then the glue solution was condensed by wet method, dried, and the grafting agent of brominated star-branched butyl rubber was prepared.

[0086] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: Firstly, in a 4L jacketed stainless steel reactor, the reactor was purged with nitrogen for 3 times, then 350g methyl chloride, 150g cyclohexane, and 25g grafting agent of brominated star-branched butyl rubber were added into the reactor, and the stirring and dissolution were carried out for 80min until complete dissolution; then the temperature was lowered to -75℃, and then 500g isobutene, 500g methyl chloride, and 15g isoprene were added into the reactor in sequence, and then the temperature of the polymerization system was lowered to -80℃, and then the co-initiator solution (50g methyl chloride, 0.49g diethylaluminum chloride, and 0.01g HCl(gas) were mixed and aged for 40min at -90℃ to obtain the co-initiator solution) was added into the polymerization system, and the stirring and reaction were carried out for 5.0hr, and finally 15g ethanol was added, and then the product was discharged, condensed, washed, and dried to obtain the brominated star-branched butyl rubber with wide temperature range and high damping.

[0087] Example 2

[0088] The present embodiment provides a brominated star-branched butyl rubber, and the preparation method thereof is as follows:

[0089] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace 3 times with argon, add 2300g cyclohexane, 1000g 4-vinyl-1,2-phenyldicarboxylic acid diethyl ester, 3.5g THF into the polymerization reactor, after heating to 62℃, add 33.5mmol n-butyllithium to start the reaction for 75min; second, add 320g trans-2-methyl-1,4-dibromo-2-butene, 2.3g THF into the polymerization reactor, react for 62min; then add 170g 1,3-butadiene, 1.5g THF into the polymerization reactor, react for 42min; finally, heat to 82℃, add 80.2mmol coupling agent 1,3,5-trichlorobenzene for coupling reaction, react for 82min; then add 15g isoprene into the polymerization reactor for end-capping, react for 22min until no free monomer exists, the glue solution is condensed by wet method, dried to obtain the grafting agent of brominated star-branched butyl rubber.

[0090] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace 3 times with nitrogen, add methyl chloride 300g, cyclohexane 200g, grafting agent of brominated star-branched butyl rubber 27g into the polymerization reactor, stir and dissolve for 82min until completely dissolved; then cool to -77℃, then add methyl chloride 600g, isobutene 500g, isoprene 17g in sequence, stir and mix until the temperature of the polymerization system drops to -82℃, then add the co-initiator solution (methyl chloride 60g, hemi-ethylaluminum chloride 0.65g and HCl(gas) 0.03g) into the polymerization system, stir and react for 5.5hr after mixing and aging for 42min at -91℃, finally add 17g ethanol, discharge, condense, wash and dry to obtain the product of brominated star-branched butyl rubber with wide temperature range and high damping.

[0091] Example 3

[0092] This example provides a brominated star-branched butyl rubber, and the preparation method is as follows:

[0093] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace the reactor with argon for 4 times, then add 2500g cyclohexane, 1000g 4-vinyl-1,2-benzene dicarboxylic acid dimethyl ester, 4.0g THF into the reactor, heat to 64℃, then add 37.1mmol n-butyllithium to start the reaction for 80min; second, add 330g trans-2-methyl-1,4-dibromo-2-butene, 2.8g THF into the reactor, react for 64min; then add 200g 1,3-butadiene, 2.0g THF into the reactor, react for 44min; finally, heat to 84℃, add 160.5mmol coupling agent 1,3,5-trichlorobenzene to couple, react for 85min; then add 20g isoprene into the reactor to end-capping, react for 24min until no free monomer exists, the glue solution is condensed by wet method, dried to obtain the grafting agent of brominated star-branched butyl rubber.

[0094] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace the reactor with nitrogen for 4 times, then add methyl chloride 200g, cyclohexane 300g, the above-mentioned grafting agent of brominated star-branched butyl rubber 30g into the reactor, stir and dissolve for 84min until completely dissolved; then cool to -80℃, then add methyl chloride 700g, isobutene 500g, isoprene 20g into the reactor, stir and mix until the temperature of the polymerization system drops to -84℃, then add the co-initiator solution (methyl chloride 70g, diethylaluminum chloride 0.92g and HCl(gas) 0.05g at -95℃, mix and age for 44min to obtain the co-initiator solution) into the polymerization system, stir and react for 6.0hr, finally add 20g ethanol, then discharge, condense, wash and dry to obtain the product of brominated star-branched butyl rubber with wide temperature range and high damping.

[0095] Example 4

[0096] This example provides a kind of brominated star-branched butyl rubber, and its preparation method is as follows:

[0097] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace the reactor with argon for 4 times, then add 2600g pentane, 1000g 4-vinyl-1,2-phenyldicarboxylic acid diethyl ester, 4.3g DGE into the reactor, after heating to 66℃, add 39.5mmol n-butyllithium to start the reaction for 83min; second, add 350g trans-2-methyl-1,4-dibromo-2-butene, 3.3g THF into the reactor, react for 66min; then add 210g 1,3-butadiene, 2.4g THF into the reactor, react for 46min; finally, heat to 86℃, add 240.5mmol coupling agent 1,3,5-trichlorobenzene to couple, react for 87min; then add 23g isoprene into the reactor to cap, react for 26min until no free monomer exists, the glue solution is coagulated by wet method, dried to obtain the grafting agent of brominated star-branched butyl rubber.

[0098] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace the reactor with nitrogen for 4 times, then add dichloromethane 600g, pentane 1400g, the above-mentioned grafting agent of brominated star-branched butyl rubber 32g into the reactor, stir and dissolve for 86min until completely dissolved; then cool to -81℃, then add dichloromethane 800g, isobutene 500g, isoprene 21g into the reactor, stir and mix until the temperature of the polymerization system drops to -86℃, then add the co-initiator solution (dichloromethane 80g, 1-chlorodiisobutylaluminum 1.15g and HCl(gas) 0.07g, mixed and aged for 46min at -97℃ to obtain the co-initiator solution) into the polymerization system, stir and react for 6.3hr, finally add 22g ethanol, then discharge, coagulate, wash and dry to obtain the product of brominated star-branched butyl rubber with wide temperature range and high damping.

[0099] Example 5

[0100] This example provides a brominated star-branched butyl rubber, and the preparation method is as follows:

[0101] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace 5 times with argon, then add 2800g cyclohexane, 1000g 4-vinyl-1,2-phenyldicarboxylic acid diethyl ester, 4.6g THF into the polymerization reactor, after heating to 68℃, add 42.3mmol n-butyllithium to start the reaction for 87min; then add 370g trans-2-methyl-1,4-dibromo-2-butene, 3.7g THF into the polymerization reactor, react for 68min; then add 230g 1,3-butadiene, 2.8g THF into the polymerization reactor, react for 48min; finally, heat to 88℃, add 330.6mmol coupling agent 1,3,5-trichlorobenzene for coupling reaction, react for 88min; then add 26g isoprene into the polymerization reactor for end-capping, react for 28min until no free monomer exists, the glue solution is condensed by wet method, dried to obtain the grafting agent of brominated star-branched butyl rubber.

[0102] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace 5 times with nitrogen, then add methyl chloride 1000g, cyclohexane 1000g, the above-mentioned grafting agent of brominated star-branched butyl rubber 33g into the polymerization reactor, stir and dissolve for 88min until completely dissolved; then cool to -83℃, then add methyl chloride 900g, isobutene 500g, isoprene 23g in sequence, stir and mix until the temperature of the polymerization system drops to -88℃, then add the co-initiator solution (methyl chloride 90g, 1.31g of hemi-ethyl aluminum chloride and 0.09g of HCl(gas) at -98℃, mix and age for 48min to obtain the co-initiator solution) into the polymerization system, stir and react for 6.7hr, finally add 23g ethanol, discharge, condense, wash, and dry to obtain the product of brominated star-branched butyl rubber with wide temperature range and high damping.

[0103] Example 6

[0104] This example provides a kind of brominated star-branched butyl rubber, and its preparation method is as follows:

[0105] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace 5 times with argon, add 3000g cyclohexane, 1000g 4-vinyl-1,2-phthalic acid dioctyl ester, 5.0g THF into the polymerization reactor, after heating to 70℃, add 44.1mmol n-butyllithium to start the reaction for 90min; second, add 400g trans-2-methyl-1,4-dibromo-2-butene, 4.0g THF into the polymerization reactor, react for 70min; then add 250g 1,3-butadiene, 3.0g THF into the polymerization reactor, react for 50min; finally, heat to 90℃, add 441mmol coupling agent 1,3,5-trichlorobenzene for coupling reaction, react for 90min; then add 30g isoprene into the polymerization reactor for end-capping, react for 30min until no free monomer exists, the glue solution is coagulated by wet method, dried to obtain the grafting agent of brominated star-branched butyl rubber.

[0106] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace 5 times with nitrogen, add methyl chloride 1400g, cyclohexane 600g, the above-mentioned grafting agent of brominated star-branched butyl rubber 35g into the polymerization reactor, stir and dissolve for 90min until completely dissolved; then cool to -85℃, then add methyl chloride 1000g, isobutene 500g, isoprene 25g in sequence, stir and mix until the temperature of the polymerization system drops to -90℃, then add the co-initiator solution (methyl chloride 100g, 1.50g of diethylaluminum chloride and 0.15g of HCl(gas) at -100℃, mix and age for 50min to obtain the co-initiator solution) into the polymerization system, stir and react for 7.0hr, finally add 25g ethanol, discharge, coagulate, wash and dry to obtain the product of brominated star-branched butyl rubber with wide temperature range and high damping.

[0107] Example 7

[0108] This example provides a brominated star-branched butyl rubber, and the preparation method is as follows:

[0109] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, the 15L jacketed stainless steel reactor was replaced with argon for 5 times, 3000g hexane, 1000g 4-vinyl-1,3-benzenedicarboxylic acid diethyl ester, 5.0g DME were added into the polymerization kettle, after heating to 70℃, 44.1mmol n-butyllithium was added to start the reaction for 90min; secondly, 400g trans-2-methyl-1,4-dibromo-2-butene, 4.0g THF were added into the polymerization kettle, and the reaction was carried out for 70min; then, 250g 1,3-butadiene, 3.0g THF were added into the polymerization kettle, and the reaction was carried out for 50min; finally, the temperature was raised to 90℃, and 441mmol 1,3,5-trichlorobenzene was added for coupling reaction, and the reaction was carried out for 90min; subsequently, 30g capping agent 1,3-butadiene was added into the polymerization kettle for capping, and the reaction was carried out for 30min until no free monomer existed; the glue liquid was condensed by wet method, dried, and the grafting agent of brominated star-branched butyl rubber was prepared.

[0110] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: first, the 4L jacketed stainless steel reactor was replaced with nitrogen for 5 times, 1400g dichloroethane, 600g hexane, and 35g of the above-mentioned grafting agent of brominated star-branched butyl rubber were added into the polymerization kettle, and the stirring and dissolution were carried out for 90min until complete dissolution; then, the temperature was lowered to-85℃, and 1000g dichloroethane, 500g isobutene, and 25g isoprene were sequentially added, and the stirring and mixing were carried out until the temperature of the polymerization system was lowered to-90℃; then, the co-initiator solution (100g dichloroethane, 1.50g of hemi-isobutyl aluminum chloride, and 0.15g of HBr (gas) were mixed and aged for 50min at-100℃ to obtain the co-initiator solution) was added into the polymerization system, and the stirring and reaction were carried out for 7.0hr; finally, 25g ethanol was added, and the product was discharged, condensed, washed, and dried to obtain the brominated star-branched butyl rubber with wide temperature range and high damping.

[0111] Comparative Example 1

[0112] The preparation method of the brominated star-branched butyl rubber provided in the present comparative example was similar to that of Example 1, and the only difference was that: 1) methyl methacrylate was used to replace 4-vinyl-1,2-benzenedicarboxylic acid diethyl ester in the preparation process of the grafting agent of brominated star-branched butyl rubber, and 2) the grafting agent used in the preparation of brominated star-branched butyl rubber was different; the specific preparation method of the brominated star-branched butyl rubber provided in the present comparative example was as follows:

[0113] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: First, the 15L jacketed stainless steel reactor was replaced with argon for 3 times, and then 2000g of cyclohexane, 1000g of ethyl methacrylate, and 3.0g of THF were sequentially added into the polymerization kettle. After being heated to 60℃, 30.9mmol of n-butyllithium was added to start the reaction for 70min. Then, 300g of trans-2-methyl-1,4-dibromo-2-butene and 2.0g of THF were added into the polymerization kettle, and the reaction was carried out for 60min. Then, 150g of 1,3-butadiene and 1.0g of THF were added into the polymerization kettle, and the reaction was carried out for 40min. Finally, the temperature was increased to 80℃, and 30.9mmol of 1,3,5-trichlorobenzene was added for coupling reaction, and the reaction was carried out for 80min. Subsequently, 10g of isoprene was added into the polymerization kettle for end-capping, and the reaction was carried out for 20min until no free monomer was present. The glue liquid was then coagulated by wet method, dried, and the grafting agent-1 of brominated star-branched butyl rubber was prepared.

[0114] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: First, the 4L jacketed stainless steel reactor was replaced with nitrogen for 3 times, and then 350g of methyl chloride, 150g of cyclohexane, and 25g of the grafting agent-1 of brominated star-branched butyl rubber were added into the polymerization kettle. The mixture was stirred and dissolved for 80min until complete dissolution. Then, the temperature was decreased to -75℃, and then 500g of isobutene, 500g of methyl chloride, and 15g of isoprene were sequentially added into the polymerization kettle. The mixture was stirred and mixed until the temperature of the polymerization system decreased to -80℃. Then, the co-initiator solution (50g of methyl chloride, 0.49g of hemi-ethyl aluminum chloride, and 0.01g of HCl(gas) at -90℃) was added into the polymerization system and stirred for 5.0hr. Finally, 15g of ethanol was added, and the product was obtained by discharging, washing, and drying.

[0115] Comparative Example 2

[0116] The preparation method of the brominated star-branched butyl rubber provided in the present comparative example is similar to that of Example 2, with the only difference being that: 1) 1,2-dibromoethylene is used instead of trans-2-methyl-1,4-dibromo-2-butene in the preparation process of the grafting agent of brominated star-branched butyl rubber; and 2) the grafting agent used in the preparation of brominated star-branched butyl rubber is different. The specific preparation method of the brominated star-branched butyl rubber provided in the present comparative example is as follows:

[0117] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, the 15L jacketed stainless steel reactor was purged with argon for 3 times, and then 2300g of cyclohexane, 1000g of 4-vinyl-1,2-benzenedicarboxylic acid diethyl ester, and 3.5g of THF were sequentially added into the polymerization kettle. After being heated to 62℃, 33.5mmol of n-butyllithium was added to start the reaction for 75min. Then, 320g of 1,2-dibromoethylene and 2.3g of THF were added into the polymerization kettle, and the reaction was carried out for 62min. Subsequently, 170g of 1,3-butadiene and 1.5g of THF were added into the polymerization kettle, and the reaction was carried out for 42min. Finally, the temperature was increased to 82℃, and 80.2mmol of the coupling agent 1,3,5-trichlorobenzene was added for coupling reaction, and the reaction was carried out for 82min. Subsequently, 15g of isoprene was added into the polymerization kettle for end-capping, and the reaction was carried out for 22min until no free monomer existed. The glue solution was condensed by wet method, dried, and the grafting agent-2 of brominated star-branched butyl rubber was prepared.

[0118] (2) Preparation of the brominated star-branched butyl rubber with wide temperature range and high damping: first, the 4L jacketed stainless steel reactor was purged with nitrogen for 3 times, and then 300g of methyl chloride, 200g of cyclohexane, and 227g of the grafting agent of brominated star-branched butyl rubber were added into the polymerization kettle. After being stirred and dissolved for 82min, the temperature was decreased to -77℃. Then, 600g of methyl chloride, 500g of isobutene, and 17g of isoprene were sequentially added into the polymerization kettle. After the temperature of the polymerization system was decreased to -82℃, the co-initiator solution (60g of methyl chloride, 0.65g of diethylaluminum chloride, and 0.03g of HCl(gas) at -91℃) was added into the polymerization system, and the reaction was carried out for 5.5hr. Finally, 17g of ethanol was added, and the product was obtained by discharging, washing, and drying.

[0119] Comparative Example 3

[0120] The preparation method of the brominated star-branched butyl rubber provided in the present comparative example was similar to that of Example 3, and the only difference was that: 1) the addition order of 4-vinyl-1,2-benzenedicarboxylic acid dimethyl ester and trans-2-methyl-1,4-dibromo-2-butene was different in the preparation process of the grafting agent of brominated star-branched butyl rubber; 2) different grafting agents were used in the preparation of the brominated star-branched butyl rubber. The specific preparation method of the brominated star-branched butyl rubber provided in the present comparative example was as follows:

[0121] (1) Preparation of the grafting agent of brominated star branched butyl rubber: first, in a 15L jacketed stainless steel reactor, replace 4 times with argon, add 2500g cyclohexane, 330g trans-2-methyl-1,4-dibromo-2-butene, 2.8g THF into the polymerization reactor, after heating to 64℃, add 37.1mmol n-butyllithium to start the reaction for 80min; second, add 1000g 4-vinyl-1,2-benzenedicarboxylic acid dimethyl ester, 4.0g THF into the polymerization reactor, react for 64min; then add 200g 1,3-butadiene, 2.0g THF into the polymerization reactor, react for 44min; subsequently, add 20g isoprene into the polymerization reactor for end-capping, react for 24min until no free monomer exists, the glue liquid is condensed by wet method, dried to obtain the grafting agent-3 of brominated star branched butyl rubber.

[0122] (2) Preparation of brominated star branched butyl rubber with wide temperature range and high damping: first, in a 4L jacketed stainless steel reactor, replace 4 times with nitrogen, add methyl chloride 200g, cyclohexane 300g, functional polymer damping three-arm brominated grafting agent-3 330g into the polymerization reactor, stir and dissolve for 84min until completely dissolved; then cool to -80℃, then add methyl chloride 700g, isobutene 500g, isoprene 20g in sequence, stir and mix until the temperature of the polymerization system drops to -84℃, then add methyl chloride 70g, hemiethyl aluminum chloride 0.92g and HCl(gas) 0.05g at -95℃, mix and age for 44min, then add them into the polymerization system, stir and react for 6.0hr, finally add 20g ethanol, discharge, condense, wash, dry to obtain the brominated star branched butyl rubber product with wide temperature range and high damping.

[0123] Comparative Example 4

[0124] The preparation method of the brominated star branched butyl rubber provided in this comparative example is similar to that of Example 4, the difference is only that: 1) free radical polymerization is used instead of anionic polymerization in the preparation process of the grafting agent of brominated star branched butyl rubber; 2) the grafting agent used in the preparation of brominated star branched butyl rubber is different; the specific preparation method of the brominated star branched butyl rubber provided in this comparative example is as follows:

[0125] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: First, the 15L jacketed stainless steel reactor was replaced with argon for 4 times, and then 2600g of pentane, 1000g of 4-vinyl-1,2-benzene dicarboxylate diethyl ester, and 4.3g of DGE were sequentially added into the polymerization kettle. After being heated to 66℃, 39.5mmol of BPO (benzoyl peroxide) was added to start the reaction for 83min. Then, 350g of trans-2-methyl-1,4-dibromo-2-butene and 3.3g of THF were added into the polymerization kettle, and the reaction was carried out for 66min. Then, 210g of 1,3-butadiene and 2.4g of THF were added into the polymerization kettle, and the reaction was carried out for 46min. Finally, the temperature was increased to 86℃, 240.5mmol of 1,3,5-trichlorobenzene was added for coupling reaction, and the reaction was carried out for 87min. Then, 23g of isoprene was added into the polymerization kettle for end-capping, and the reaction was carried out for 26min until no free monomer was present. The glue liquid was condensed by wet method, dried, and the grafting agent-4 of brominated star-branched butyl rubber was prepared.

[0126] (2) Preparation of brominated star-branched butyl rubber with wide temperature range and high damping: First, the 4L jacketed stainless steel reactor was replaced with nitrogen for 4 times, and then 600g of dichloromethane, 1400g of pentane, and 432g of the grafting agent of brominated star-branched butyl rubber were added into the polymerization kettle. The stirring and dissolution were carried out for 86min until complete dissolution. Then, the temperature was decreased to -81℃, and then 800g of dichloromethane, 500g of isobutene, and 21g of isoprene were sequentially added into the polymerization kettle. After the temperature of the polymerization system was decreased to -86℃, the co-initiator solution (80g of dichloromethane, 1.15g of dichloro-diisobutylaluminum, and 0.07g of HCl (gas) were mixed and aged for 46min at -97℃ to obtain the co-initiator solution) was added into the polymerization system. After stirring for 6.3hr, 22g of ethanol was added, and then the product was discharged, washed, and dried to obtain the brominated star-branched butyl rubber with wide temperature range and high damping.

[0127] Comparative Example 5

[0128] The preparation method of the brominated star-branched butyl rubber provided in the present comparative example is similar to that of Example 5, and the only difference is that: 1) no isoprene is added for end-capping in the preparation process of the grafting agent of brominated star-branched butyl rubber; and 2) the grafting agent used in the preparation of brominated star-branched butyl rubber is different. The specific preparation method of the brominated star-branched butyl rubber provided in the present comparative example is as follows:

[0129] (1) Preparation of the grafting agent of brominated star-branched butyl rubber: first, the 15L jacketed stainless steel reactor was replaced with argon for 5 times, 2800g cyclohexane, 1000g 4-vinyl-1,2-benzene dicarboxylic acid diethyl ester, 4.6g THF were added into the polymerization reactor, after heating to 68℃, 42.3mmol n-butyllithium was added to start the reaction for 87min; secondly, 370g trans-2-methyl-1,4-dibromo-2-butene, 3.7g THF were added into the polymerization reactor, the reaction was carried out for 68min; then, 230g 1,3-butadiene, 2.8g THF were added into the polymerization reactor, the reaction was carried out for 48min; finally, the temperature was raised to 88℃, 330.6mmol coupling agent 1,3,5-trichlorobenzene was added for coupling reaction, the reaction was carried out for 88min; finally, the glue solution was condensed by wet method, dried, and the grafting agent-5 of brominated star-branched butyl rubber was prepared.

[0130] (2) Preparation of the brominated star-branched butyl rubber with wide temperature range and high damping: first, the 4L jacketed stainless steel reactor was replaced with nitrogen for 5 times, 1000g methyl chloride, 1000g cyclohexane, 533g grafting agent-5 of brominated star-branched butyl rubber were added into the polymerization reactor, and stirred and dissolved for 88min until completely dissolved; then, the temperature was lowered to -83℃, and then 900g methyl chloride, 500g isobutene, 23g isoprene were added in sequence, and stirred and mixed until the temperature of the polymerization system was lowered to -88℃, then the co-initiator solution (90g methyl chloride, 1.31g diethylaluminum chloride and 0.09g HCl(gas) were mixed and aged at -98℃ for 48min to obtain the co-initiator solution) was added into the polymerization system, and stirred and reacted for 6.7hr, finally 23g ethanol was added, and then the product was discharged, condensed, washed and dried to obtain the brominated star-branched butyl rubber with wide temperature range and high damping.

[0131] Comparative Example 6

[0132] The preparation method of the brominated star-branched butyl rubber provided in the present comparative example is similar to that of Example 6, and the only difference is that the addition amount of the grafting agent is different when preparing the brominated star-branched butyl rubber with wide temperature range and high damping; the specific preparation method of the brominated star-branched butyl rubber provided in the present comparative example is as follows:

[0133] (1) Preparation of the grafting agent-6 of brominated star-branched butyl rubber: same as Example 6.

[0134] (2) Preparation of brominated star branched butyl rubber with wide temperature range and high damping: first, nitrogen was introduced into a 4L jacketed stainless steel reactor for 5 times, and then 1400g of methyl chloride, 600g of cyclohexane and 15g of the grafting agent of the brominated star branched butyl rubber-6 were added into the polymerization reactor, and stirred and dissolved for 90min until complete dissolution; then the temperature was lowered to-85℃, and then 1000g of methyl chloride, 500g of isobutene and 25g of isoprene were sequentially added, and the polymerization system was stirred until the temperature dropped to-90℃, and then a co-initiator solution (100g of methyl chloride, 1.50g of diethylaluminum chloride and 0.15g of HCl (gas) were mixed at-100℃ for 50min to obtain the co-initiator solution) was added into the polymerization system, and stirred for 7.0hr, and finally 25g of ethanol was added, and then the product was discharged, washed and dried to obtain the brominated star branched butyl rubber with wide temperature range and high damping.

[0135] Experimental Example

[0136] The grafting agent of the brominated star branched butyl rubber prepared in each example and comparative example was subjected to determination of molecular weight and distribution and bromine content, and the specific results are shown in the following table.

[0137] Table 1

[0138] Number average molecular weight Mn Molecular weight distribution Mw / Mn Bromine content % n I Example 1 60100 4.51 4.12 n≥1 isoprene Example 2 62000 4.73 4.35 n≥1 isoprene Example 3 64200 4.85 4.61 n≥1 isoprene Example 4 66500 4.96 4.87 n≥1 isoprene Example 5 68100 5.03 5.06 n≥1 isoprene Example 6 70000 5.12 5.26 n≥1 isoprene Example 7 68000 5.06 5.13 n≥1 1,3-butadiene Comparative Example 1 56000 4.06 4.32 n≥1 isoprene Comparative Example 2 59000 4.18 4.42 n≥1 isoprene Comparative Example 3 63900 2.65 4.59 n≥1 isoprene Comparative Example 4 56000 5.38 4.51 n≥1 isoprene Comparative Example 5 67900 5.01 5.07 n≥1 isoprene Comparative Example 6 70000 5.12 5.26 n≥1 isoprene

[0139] As shown in Table 1, the preparation method provided by the present application can prepare the grafting agent of Formula 1 with a number average molecular weight (Mn) of 60100-70000 and a bromine content of 4.12wt%-5.26wt%.

[0140] The brominated star branched butyl rubber product prepared in each example and comparative example was subjected to determination of molecular weight and distribution and bromine content, and the specific results are shown in the following table.

[0141] Table 2 Properties of brominated star branched butyl rubber with wide temperature range and high damping

[0142]

[0143] As shown in Table 2, the effective damping temperature range, the maximum damping factor and the tensile strength of the butyl rubber prepared by the present application are widened and increased with the increase of the number average molecular weight Mn and the bromine content of the grafting agent; the Mooney relaxation of the butyl rubber is reduced with the widening of the molecular weight distribution Mw / Mn of the grafting agent, which indicates that the grafting agent prepared by the present application is helpful to realize the high-efficiency modification of the butyl rubber, and the modified butyl rubber exhibits wide effective damping temperature range, high damping, excellent processing characteristics, mechanical properties and air tightness.

[0144] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, and these corresponding changes and modifications shall all belong to the protection scope of the claims of the present application.

Claims

1. A method for preparing a grafting agent for brominated star-branched butyl rubber, characterized in that, Includes the following steps: S1, in an anhydrous and oxygen-free environment, the structure modifier, 4-vinyl-1,2-phthalic acid diester or its isomer are mixed in a solvent and heated to 60~70℃, and then an initiator is added to carry out the first anionic polymerization reaction. S2, after the first anionic polymerization reaction is completed, trans-2-methyl-1,4-dibromo-2-butene and a structure modifier are added to carry out the second anionic polymerization reaction; S3, after the second anionic polymerization reaction is completed, 1,3-butadiene and a structure modifier are added to carry out the third anionic polymerization reaction; S4. After the third anionic polymerization reaction is completed, the system is heated to 80~90℃, a coupling agent is added to carry out a coupling reaction, and then a sealing agent is added to seal the end until there are no free monomers. The resulting adhesive is wet coagulated and dried to obtain the grafting agent of the brominated star-branched butyl rubber. The coupling agent is 1,3,5-trichlorobenzene, 1,3,5-tribromobenzene or tert-butylsilicon trichloride; The capping agent is selected from 1,3-butadiene or isoprene; The grafting agent for the brominated star-branched butyl rubber has a number average molecular weight of 60,000 to 70,000 and a bromine content of 4.12 wt% to 5.26 wt%. The 4-vinyl-1,2-phthalate diester or its isomers are selected from any one of 4-vinyl-1,2-phthalate dimethyl ester, 4-vinyl-1,2-phthalate diethyl ester, 4-vinyl-1,2-phthalate dipropyl ester, 4-vinyl-1,2-phthalate dibutyl ester, 4-vinyl-1,2-phthalate diisobutyl ester, 4-vinyl-1,2-phthalate diisopentyl ester, 4-vinyl-1,2-phthalate dihexyl ester, 4-vinyl-1,2-phthalate diheptyl ester, 4-vinyl-1,2-phthalate dioctyl ester, and 4-vinyl-1,3-phthalate diethyl ester.

2. The preparation method according to claim 1, characterized in that, The grafting agent for the brominated star-branched butyl rubber has a molecular weight distribution of 4.51~5.

12.

3. The preparation method according to claim 1, characterized in that, The 4-vinyl-1,2-phthalic acid diester or its isomer is 4-vinyl-1,2-phthalic acid diethyl ester.

4. The preparation method according to claim 1, characterized in that, The coupling agent is 1,3,5-trichlorobenzene.

5. The preparation method according to claim 1, characterized in that, Based on the amount of the 4-vinyl-1,2-phthalic acid diester or its isomer as 100%, in step S1, the amount of the solvent is 200%~300%, the amount of the structure modifier is 0.3%~0.5%, and the time of the first anionic polymerization reaction is 70~90 min; and / or Based on the amount of the 4-vinyl-1,2-phthalic acid diester or its isomer as 100%, in step S2, the amount of trans-2-methyl-1,4-dibromo-2-butene is 30%~40%, the amount of the structure modifier is 0.2%~0.4%, and the time of the second anionic polymerization reaction is 60~70 min; and / or Based on the amount of the 4-vinyl-1,2-phthalic acid diester or its isomer as 100%, in step S3, the amount of the 1,3-butadiene is 15% to 25%, the amount of the structure modifier is 0.1% to 0.3%, and the time of the third anionic polymerization reaction is 40 to 50 minutes; in step S4, the amount of the end-capping agent is 1.0% to 3.0%.

6. The preparation method according to claim 4, characterized in that, The initiator is RLi, wherein R is selected from C1~C20 straight-chain or branched alkyl groups, and C6~C12 substituted or unsubstituted aryl groups; The structure modifier is selected from any one of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, and triethylamine.

7. The preparation method according to claim 6, characterized in that, The molar ratio of the coupling agent to RLi is 1:1 to 10:

1.

8. The preparation method according to claim 6, characterized in that, The initiator is selected from any one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium.

9. The preparation method according to claim 8, characterized in that, The initiator is n-butyllithium.

10. The preparation method according to claim 6, characterized in that, The structure modifier is tetrahydrofuran.

11. A method for preparing brominated star-branched butyl rubber, characterized in that, Includes the following steps: A1. The diluent and co-initiator are mixed and aged at -100~-90℃ to obtain the co-initiator solution; In an anhydrous and oxygen-free environment, the grafting agent is dissolved in a mixed solvent, then cooled to -85~-75℃, and then the diluent, isobutylene and isoprene are added in sequence. The mixture is stirred until the temperature of the polymerization system drops to -90~-80℃, and then the co-initiator solution is added to carry out the cationic polymerization reaction. After the cationic polymerization reaction is completed, the terminator is added, the material is discharged and coagulated, washed and dried to obtain the brominated star-branched butyl rubber. Wherein, the grafting agent is the grafting agent for brominated star-branched butyl rubber prepared by the method for preparing the grafting agent for brominated star-branched butyl rubber according to any one of claims 1-10. With the amount of isobutylene being 100%, the amount of grafting agent is 5% to 7%. The co-initiator is a mixture of alkyl aluminum halide and protic acid.

12. The preparation method according to claim 11, characterized in that, With the isobutylene used in a 100% concentration, the diluent used in a 10% to 20% concentration and the co-initiator used in a 0.2% to 0.6% concentration; and / or With the amount of isobutylene as 100%, in step A2, the amount of the mixed solvent is 100% to 400%, the amount of the diluent is 100% to 200%, the amount of isoprene is 3% to 5%, and the amount of the terminator is 3% to 5%.

13. The preparation method according to claim 11, characterized in that, The cationic polymerization reaction takes 5-7 hours.

14. The preparation method according to claim 11, characterized in that, The diluent is a C1-C4 haloalkane, wherein the halogen atom in the haloalkane is selected from chlorine, bromine or fluorine.

15. The preparation method according to claim 11, characterized in that, The mass ratio of the protic acid to the alkyl aluminum halide is 0.01:1 to 0.1:

1.

16. The preparation method according to claim 15, characterized in that, 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 any one of HCl, HF, HBr, H2SO4, H2CO3, H3PO4, and HNO3.

17. The preparation method according to claim 11, characterized in that, The mixed solvent is a mixture of diluent and hydrocarbon solvent.

18. The preparation method according to claim 11, characterized in that, The terminating agent is selected from at least one of methanol, ethanol, and butanol.

19. The preparation method according to claim 14, characterized in that, The diluent is any one of chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane.

20. The preparation method according to claim 19, characterized in that, The diluent is chloromethane.

21. The preparation method according to claim 16, characterized in that, The alkyl aluminum halide is sesquiethyl aluminum chloride.

22. The preparation method according to claim 16, characterized in that, The protic acid is HCl.

23. The preparation method according to claim 17, characterized in that, The volume ratio of the diluent to the hydrocarbon solvent is (7~3):(3~7).

24. The preparation method according to any one of claims 11-23, characterized in that, The effective damping temperature range of the brominated star-branched butyl rubber is -85℃ to 96℃, and the maximum damping factor is tanδ. max ≥2.7.

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