CN113831476A

CN113831476A - Preparation method of low-saturation butyl rubber

Info

Publication number: CN113831476A
Application number: CN202010591391.4A
Authority: CN
Inventors: 徐典宏; 张华强; 孟令坤; 翟云芳; 朱晶; 冯旭; 肖晔
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2021-12-24
Anticipated expiration: 2040-06-24
Also published as: CN113831476B

Abstract

The invention relates to a preparation method of low-saturation butyl rubber. The method firstly takes styrene, butadiene and isoprene as reaction monomers and takes alkyl lithium as an initiator to synthesize the ternary block copolymer [ -IR-BR-SBR-B- ] n. The ternary block copolymer is used as a grafting agent, and isobutylene and isoprene are subjected to cationic polymerization to prepare the low-saturation butyl rubber in a catalytic system compounded by alkyl aluminum halide and protonic acid. According to the invention, the vulcanization efficiency is improved and the vulcanization degree is increased by improving the unsaturation degree of the butyl rubber, so that the problems of low vulcanization efficiency and extrusion swelling of the butyl rubber in the processing process are effectively solved, the sufficient crude rubber strength and good air tightness of the butyl rubber are maintained, and the balance between the physical and mechanical properties and the processing properties of the butyl rubber is endowed. The method has the characteristics of short process flow, controllable molecular weight, good product processing performance, suitability for industrial production and the like.

Description

Preparation method of low-saturation butyl rubber

Technical Field

The invention relates to a preparation method of low-saturation butyl rubber, in particular to a method for preparing low-saturation butyl rubber by cationic polymerization of isoprene, butadiene and styrene ternary block copolymer, isobutene and isoprene.

Background

It is known that Butyl Rubber (IIR) is produced by the cationic polymerization of isobutylene and a small amount of isoprene. Butyl rubber has been commercialized by Exxon corporation in the 40 th century for over seventy years since now, and has excellent properties such as airtightness, damping properties, thermal aging resistance, ozone resistance, and weather resistance, and thus it is widely used in the fields of manufacturing inner tubes, airtight layers, curing bladders, medical stoppers of tires for vehicles, and the like, and is one of the most important synthetic rubber products.

However, the molecular chain of the butyl rubber is mainly composed of carbon-carbon single bonds, the number of double bonds is small, and the substituent methyl groups are symmetrically arranged, so that the defects of high crystallinity, poor flexibility of the molecular chain, low stress relaxation rate, low vulcanization speed, poor adhesiveness, poor compatibility with other general rubbers and the like exist, and the butyl rubber is easy to excessively flow and deform in the processing process. Therefore, how to balance the physical and mechanical properties and the processability of the butyl rubber becomes a bottleneck for preparing high-performance butyl rubber materials.

In recent years, researchers find that a small amount of double bonds are introduced into a saturated molecular main chain of butyl rubber, so that the vulcanization speed can be increased, the vulcanization degree can be increased, the vulcanization performance of the butyl rubber can be improved, and the swelling phenomenon after an extrusion molding die is reduced; meanwhile, the size stability, the stress at definite elongation and the tensile strength of the rubber compound can be increased, and the compatibility of the butyl rubber and other unsaturated rubbers can be improved. Therefore, the development of the butyl rubber with low saturation can solve the contradiction between the strength of the butyl rubber and the extrusion swelling in the processing process, and realize the balance and unification of the physical and mechanical properties and the processing properties of the butyl rubber.

In the prior art, researches on improving the processability of butyl rubber and improving the crude rubber strength are mainly solved by preparing broad molecular weight distribution, bimodal distribution and star-shaped high-branched butyl rubber by a core-arm-first method, an arm-first-core-second method and a core-arm simultaneous method. Such as: US5395885 discloses a star-branched polyisobutylene-polydivinylbenzene polymer, which is synthesized by taking polyisobutylene as an arm, Polydivinylbenzene (PDVB) as a core, a complex of aluminium chloride and water as an initiator, and methyl chloride as a diluent through a first-arm-second-core method at-90 ℃ to-100 ℃. CN 107344982 a discloses a method for producing a wide/bimodal molecular weight distribution butyl rubber, which comprises: mixing isobutene and isoprene at a molar ratio of 97:3 to 99:1, then mixing the mixture with a diluent (methane chloride) to obtain a monomer stream, mixing an initiator (an aluminum chloride system and an HCl/alkylaluminum chloride complex) with the diluent (methane chloride) to obtain an initiator stream, mixing the monomer stream and the initiator stream, conveying the mixture into a first loop reactor zone, and carrying out polymerization reaction for 5-10min at a temperature of-98 ℃ to-96 ℃ and a pressure of 0.3 to 0.4MPa to obtain a first part of butyl rubber slurry; secondly, sending the first part of butyl rubber slurry into a second loop reactor zone, and carrying out polymerization reaction for 5-10min at the temperature of-92 ℃ to-90 ℃ and the pressure of 0.1 to 0.2Mpa to finally obtain the butyl rubber slurry with broad/bimodal molecular weight distribution; and thirdly, contacting the butyl rubber slurry with broad/bimodal molecular weight distribution with water, removing unreacted monomers and a diluent to obtain colloidal particle water, and then dehydrating and drying the colloidal particle water to obtain the butyl rubber with broad/bimodal molecular weight distribution and molecular weight distribution (Mw/Mn) of at least 5.0. CN1427851A discloses a preparation method of butyl rubber with wide molecular weight distribution. The process uses a mixed catalyst system (comprising a large amount ofMixtures of an internalized dialkylaluminum, a minor amount of a monoalkylaluminum dihalide, and a minor amount of an aluminoxane) to obtain a broad distribution butyl rubber having a molecular weight distribution of greater than 3.5, up to 7.6. CN101353403B discloses a preparation method of star-branched polyisobutylene or butyl rubber, which adopts a polystyrene/isoprene block copolymer with a silicon-chlorine group at the terminal or a polystyrene/butadiene block copolymer with a silicon-chlorine group at the terminal as a grafting initiating agent for positive ion polymerization, directly participates in the positive ion polymerization in a positive ion polymerization system of a mixed solvent with a ratio of methane chloride to cyclohexane v: v of 20-80/80-20 at the temperature of 0-100 ℃, and prepares a star-branched polyisobutylene or butyl rubber product by the participation of an unsaturated chain in a grafting reaction through the initiated positive ion polymerization of the silicon-chlorine group. CN01817708.5 provides a method of making star-branched polymers by adding a multiolefin cross-linking agent, such as divinylbenzene, and a chain transfer agent, such as 2,4, 1-trimethyl-1-pentene, to a mixture of isoolefin monomers and diolefin monomers. CN88108392.5 discloses a star-shaped grafted butyl rubber with a comb-shaped structure, which is prepared by using a hydrochloric acid polystyrene-isoprene copolymer as a multifunctional initiator or using polystyrene-butadiene or polystyrene-isoprene as a grafting agent. CN 107793535A provides a butyl rubber having a molecular weight of 90 to 260 ten thousand, Log (MW)>And contains structural units derived from isobutylene, structural units derived from a conjugated diene, and optionally structural units derived from an aryl olefin. US3780002 teaches a composite initiator using a halide of a metal from group II or III of the periodic Table of the elements in combination with a tetrahalide of a metal from group IV of the periodic Table of the elements, e.g. A1Cl₃And TiC1₄Combined use, or A1C1₃And SnC1₄The composite use enables each initiator to independently initiate cationic polymerization, and butyl rubber with molecular weight distribution index Mw/Mn of above 5.0 is synthesized under the conventional butadiene rubber polymerization condition. CN 101353386A discloses an initiation system for cationic polymerization of star-branched polyisobutylene or butyl rubber, which is composed of an initiation-grafting agent, a coinitiator and a nucleophilic reagentThe method is used for initiating vinyl monomers to carry out homopolymerization, block copolymerization, star polymerization and graft copolymerization, and the obtained polymer presents obvious bimodal distribution. Puskas (Catalysts for manufacturing of IIR with biomodal molecular weight distribution: US, 5194538[ P]1993-3-16.) adopting trimesic acid as raw material to synthesize an initiator, namely tricumyl alcohol, with a three-arm structure, and then adopting a tricumyl alcohol/aluminum trichloride initiation system to initiate the copolymerization of isobutene and isoprene in an inert organic solvent at the temperature of-120 to-50 ℃ to synthesize the star-shaped low-saturation butyl rubber with bimodal molecular weight distribution. Wieland et al (Synthesis of new graft copolymerization polymerization by polymerization of the 1,1-diphenylethylene technology and cationic polymerization [ J]Polymer Science: polymer Chemistry, 2002, 40: 3725-3733.) A multi-arm star-shaped butyl rubber is successfully prepared by synthesizing a macroinitiator P (MMA-b-St-co-CMS) containing the ternary 4-chloromethylstyrene, styrene and methyl methacrylate in the presence of 1, 2-Diphenylethylene (DPE) by a free radical polymerization method, and then initiating cationic polymerization of isobutylene and isoprene by using the macroinitiator. Wubo et al (Davang S H, et al. Skid resistant coatings for air carrier decks [ J ]]Coat Technol, 1980, 52 (671): 65-69.) A poly (isoprene-styrene) block copolymer as a grafting agent is prepared by living anionic polymerization, and starlike low-saturation butyl rubber with obvious double peaks is prepared by active carbon cationic polymerization in an initiating system of 2-chloro-2, 4, 4-trimethylpentane/titanium tetrachloride/proton scavenger.

Disclosure of Invention

The invention aims to provide a preparation method of low-saturation butyl rubber. The invention firstly takes styrene, butadiene and isoprene as reaction monomers and takes alkyl lithium as an initiator to synthesize the ternary block copolymer [ -IR-BR-SBR-B- ] n. The ternary block copolymer is used as a grafting agent, and isobutylene and isoprene are subjected to cationic polymerization to prepare the low-saturation butyl rubber in a catalytic system compounded by alkyl aluminum halide and protonic acid. According to the invention, the vulcanization efficiency is improved and the vulcanization degree is increased by improving the unsaturation degree of the butyl rubber, so that the problems of low vulcanization efficiency and extrusion swelling of the butyl rubber in the processing process are effectively solved, the sufficient crude rubber strength and good air tightness of the butyl rubber are maintained, and the balance between the physical and mechanical properties and the processing properties of the butyl rubber is endowed.

All the percentages in the present invention are percentages by mass.

The preparation of the low-saturation butyl rubber is carried out in a reaction kettle, and the specific preparation process comprises the following steps:

(1) preparation of grafting agent: firstly, sequentially adding 200-300% of solvent, 30-50% of isoprene and 0.05-0.2% of structure regulator into a polymerization kettle in an inert gas atmosphere, heating to 50-60 ℃, adding an initiator to start reaction for 50-80 min to form an IR chain segment, wherein the conversion rate of the isoprene monomer reaches 100%; then, sequentially adding 100-200% of solvent, 20-30% of 1, 3-butadiene and 0.01-0.1% of structure regulator into a polymerization kettle, heating to 60-70 ℃, and reacting for 40-70 min to form an-IR-BR-chain segment, wherein the conversion rate of the 1, 3-butadiene monomer reaches 100%; secondly, sequentially adding 200-300% of solvent, 20-30% of styrene, 10-20% of butadiene and 0.05-0.15% of structure regulator into a polymerization kettle, heating to 70-80 ℃, and reacting for 50-70 min to form an-IR-BR-SBR-chain segment; and finally, adding 1-3% of butadiene into a polymerization kettle for end capping, reacting for 10-30 min until no free monomer exists, and performing wet coagulation and drying on the glue solution to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n.

(2) Preparation of low-saturation butyl rubber: according to one hundred percent of the total mass of reaction monomers, firstly, 200 to 300 percent of diluent and solvent are added into a polymerization kettle under the atmosphere of inert gas, wherein the mass ratio of the diluent to the solvent is V: the V ratio is 60-40: 40-60 percent of mixed solvent, 3-7 percent of grafting agent [ -IR-BR-SBR-B- ] n, stirring and dissolving for 30-50 min until the grafting agent is completely dissolved; and then cooling to-65 to-85 ℃, sequentially adding 100 to 200 percent of diluent, 85 to 95 percent of isobutene and 1 to 5 percent of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-100 to-90 ℃, then adding 20 to 30 percent of diluent and 0.05 to 3.0 percent of co-initiator into the polymerization system for stirring and reacting for 1.0 to 3.0 hours after mixing and aging for 20 to 30 minutes at-95 to-85 ℃, discharging and coagulating, washing and drying to obtain the low-saturation butyl rubber product.

The grafting agent is a ternary block copolymer synthesized by isoprene, 1, 3-butadiene and styrene, and the structure of the grafting agent is represented as the following [ -IR-BR-SBR-B- ] n, wherein: IR is an isoprene homopolymer block; BR is a1, 3-butadiene homopolymer block; SBR is a random copolymer block of styrene and butadiene; b is terminated butadiene, and n is 1-3; the content of isoprene in the ternary block copolymer is 30-40%, the content of 1, 3-butadiene is 30-40%, and the content of styrene is 10-20%; the number average molecular weight (Mn) of the [ -IR-BR-SBR-B- ] n ternary block copolymer is 20000-50000, and the molecular weight distribution (Mw/Mn) is 4.12-5.71.

The structure regulator of the invention is a polar organic compound which generates solvation effect in a polymerization system and can regulate the reactivity ratio of styrene and butadiene so as to ensure that the styrene and the butadiene are randomly copolymerized. Such polar organic compound is selected from one of diethylene glycol dimethyl ether (2G), Tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether (DME), triethylamine, preferably Tetrahydrofuran (THF).

The initiator is an alkyl monolithium compound, namely RLi, wherein R is a saturated aliphatic alkyl, alicyclic alkyl, aromatic alkyl containing 1-20 carbon atoms or a composite group of the above groups. The alkyl monolithium compound is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium and dodecyllithium, preferably n-butyllithium. The amount of organolithium added is determined by the molecular weight of the polymer being designed.

The diluent is halogenated alkane, wherein halogen atoms in the halogenated alkane can be chlorine, bromine or fluorine; the number of carbon atoms in the halogenated alkane being C₁-C₄. The alkyl halide is selected from the group consisting of methyl chloride, methylene chloride, carbon tetrachloride, ethylene dichloride,One of tetrachloropropane, heptachloropropane, monofluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride and fluorobutane, preferably monochloromethane.

The co-initiator is prepared by compounding alkyl aluminum halide and protonic acid according to different proportions. The alkyl aluminum halide is at least one selected from the group consisting of diethylaluminum monochloride, diisobutylaluminum monochloride, methylaluminum dichloroide, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, n-propylaluminum dichloride, isopropylaluminum dichloroide, dimethylaluminum chloride and ethylaluminum chloride, preferably ethylaluminum sesquichloride. The protonic acid is selected from HCl, HF, HBr, H₂SO₄、H₂CO₃、H₃PO₄And HNO₃Of (1), preferably HCl. Wherein the total addition amount of the coinitiator is 0.08-2.0%, and the molar ratio of the protonic acid to the alkyl aluminum halide is 0.01: 1-0.1: 1.

The type of the polymerizer of the invention is not limited, and a stainless steel polymerizer with a jacket is preferred.

The polymerization reaction of the present invention is carried out in an oxygen-free, water-free, preferably inert gas atmosphere. The polymerization and dissolution are carried out in a hydrocarbon solvent, which is a hydrocarbon solvent including straight-chain alkanes, aromatic hydrocarbons and cycloalkanes, and is selected from one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene and ethylbenzene, preferably cyclohexane.

The inert gas is nitrogen or one of all element gases in group 0 of the periodic table of elements, which do not contain radon.

The invention firstly adopts lithium alkyl as an initiator, hydrocarbons as a solvent, organic matters with certain polarity as a structure regulator, reaction monomers comprise isoprene, 1, 3-butadiene and styrene, and the initiator is added into a polymerization system at one time to synthesize the ternary block copolymer with high unsaturation degree [ -IR-BR-SBR-B- ] n. The ternary block copolymer is used as a grafting agent, and isobutylene and isoprene are subjected to cationic polymerization to prepare the low-saturation butyl rubber under a catalytic system compounded by alkyl aluminum halide and protonic acid. Because the grafting agent [ -IR-BR-SBR-B- ] n contains three-IR-, -BR-and-SBR-chain segments with different microstructures, the-IR-and-BR-chain segments can introduce a proper amount of double bonds into the saturated molecular main chain of the butyl rubber, the required vulcanization capacity is provided, the vulcanization degree is increased, the crosslinking density is improved, the problem of extrusion swelling of the butyl rubber in the processing process is effectively solved, and better processing fluidity and higher product size stability can be obtained; in addition, the SBR-chain segment contains a certain amount of benzene rings, and the benzene rings have high rigidity and large steric hindrance, so that high strength and air tightness can be obtained, and the influence of the reduction of the green strength and the air tightness caused by the-IR-and-BR-chain segments is reduced.

Therefore, the ternary block copolymer [ -IR-BR-SBR-B- ] n designed by the invention organically combines and synergistically exerts the performances of the three chain segments, solves the problems of poor sulfuration and extrusion swelling of the butyl rubber in the processing process, maintains sufficient green strength and airtightness of the butyl rubber, and realizes the balance of processability and physical and mechanical properties of the butyl rubber. The preparation method of the low-saturation butyl rubber provided by the invention has the characteristics of short process flow, controllable molecular weight, good product processability, suitability for industrial production and the like.

Detailed Description

The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.

All the raw materials used in the examples are of industrial polymerization grade, and are used after purification without other special requirements.

(1) The raw material sources are as follows:

styrene, butadiene, Polymer grade, Petroleum Lanzhou petrochemical Co Ltd

Isobutene, isoprene, Polymer grade Zhejiang Credit New materials Co Ltd

N-butyl lithium, 98% purity Nanjing Tongtiang chemical Co., Ltd

Aluminum sesquiethylate chloride, 98% pure Profenor technologies Ltd

Other reagents are all commercial products

(2) The analysis and test method comprises the following steps:

determination of the degree of unsaturation: the magnetic field strength was measured at room temperature (25 ℃ C.) using an AVANCE300 nuclear magnetic resonance apparatus from Bruker, a CDC13 solvent and TMS as an internal standard, at a magnetic field strength of 9.20 Tesla.

Determination of vulcanization characteristics: the measurement was carried out by using a rotor-less vulcanizer model GT-M2000A manufactured by Taiwan high-speed railway company according to the method specified in GB/T16584-1996.

Measurement of the extrusion swell ratio: adopting RH2000 type capillary rheometer manufactured by British Marvin company at 100 deg.C, length-diameter ratio of 16:1 and shear rate of 10-1000S^-1Is measured within the interval of (1).

Measurement of airtightness: the permeability was determined using an automated air tightness tester according to ISO 2782:1995 with a test gas of N₂The test temperature is 23 ℃, and the test sample is a circular sea piece with the diameter of 8cm and the thickness of 1 mm.

300% stress at definite elongation: the method in standard GB/T528-2009 is executed.

Example 1

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3050g of cyclohexane, 460g of isoprene and 0.9g of THF into the polymerization kettle, heating to 50 ℃, adding 18.6mmo1 n-butyllithium to start reaction, and reacting for 50min to form an IR chain segment; then adding 1500g of cyclohexane, 310g of 1, 3-butadiene and 0.8g of THF into the polymerization kettle in sequence, heating to 60 ℃, and reacting for 40min to form an-IR-BR-chain segment; secondly, 3200g of cyclohexane, 320g of styrene, 160g of 1, 3-butadiene and 1.3g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, and the reaction is carried out for 50min to form an-IR-BR-SBR-chain segment; and finally, adding 20g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 10min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 21750 and Mw/Mn of 4.23).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 670g of methane chloride, 460g of cyclohexane and 10.2g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 30min until the grafting agent is completely dissolved; and then cooling to-65 ℃, sequentially adding 400g of methane chloride, 255g of isobutene and 8.0g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, then mixing and aging 75g of methane chloride, 1.26g of sesquiethylaluminum chloride and 0.032g of HCl for 20min at-85 ℃, adding the mixture into the polymerization system together, stirring and reacting for 1.0hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 2

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3210g of cyclohexane, 510g of isoprene and 1.2g of THF into the polymerization kettle, heating to 50 ℃, adding 20.5mmo1 n-butyllithium to start reaction, and reacting for 55min to form an IR chain segment; then 1600g of cyclohexane, 330g of 1, 3-butadiene and 1.0g of THF are sequentially added into a polymerization kettle, the temperature is raised to 60 ℃, and the reaction is carried out for 45min to form an-IR-BR-chain segment; secondly, 3300g of cyclohexane, 350g of styrene, 180g of 1, 3-butadiene and 1.4g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, and the reaction is carried out for 55min to form an-IR-BR-SBR-chain segment; and finally, adding 23g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 15min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn 31230, Mw/Mn 4.51).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 650g of methane chloride, 480g of cyclohexane and 13.8g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 35min until the grafting agent is completely dissolved; and then cooling to-70 ℃, sequentially adding 420g of methyl chloride, 260g of isobutene and 10.2g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-92 ℃, then mixing and aging 80g of methyl chloride, 1.38g of sesquiethyl aluminum chloride and 0.031g of HCl for 22min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 1.5hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 3

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3300g of cyclohexane, 550g of isoprene and 1.4g of THF into the polymerization kettle, heating to 55 ℃, adding 23.5mmo1 n-butyllithium to start reaction for 60min, and forming an IR chain segment; then 1650g of cyclohexane, 350g of 1, 3-butadiene and 1.2g of THF are sequentially added into the polymerization kettle, the temperature is raised to 65 ℃, and the reaction is carried out for 50min to form an-IR-BR-chain segment; then, 3400g of cyclohexane, 370g of styrene, 200g of 1, 3-butadiene and 1.5g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 60min to form an-IR-BR-SBR-chain segment; and finally, adding 25g of 1, 3-butadiene into the polymerization kettle, carrying out end-capping reaction for 17min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 36330, Mw/Mn of 4.75).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 630g of methane chloride, 500g of cyclohexane and 15.8g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 40min until the grafting agent is completely dissolved; then cooling to-75 ℃, sequentially adding 445g of methane chloride, 266g of isobutene and 12.1g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-92 ℃, then adding 85g of methane chloride, 1.48g of sesquiethylaluminum chloride and 0.042g of HCl into the polymerization system for stirring and reacting for 2.0 hours after mixing and aging for 25 minutes under the condition of-87 ℃, discharging and condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 4

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3500g of cyclohexane, 580g of isoprene and 1.5g of THF into the polymerization kettle, heating to 55 ℃, adding 25.2mmo1 n-butyllithium to start reaction for 65min, and forming an IR chain segment; then, 1720g of cyclohexane, 370g of 1, 3-butadiene and 1.3g of THF are sequentially added into the polymerization kettle, the temperature is increased to 65 ℃, and the reaction is carried out for 55min to form an-IR-BR-chain segment; then, 3500g of cyclohexane, 390g of styrene, 220g of 1, 3-butadiene and 1.6g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 60min, so as to form an-IR-BR-SBR-chain segment; and finally, adding 28g of 1, 3-butadiene into the polymerization kettle, carrying out end-capping reaction for 20min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 38630, Mw/Mn of 4.92).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 610g of methane chloride, 550g of cyclohexane and 17.5g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 42min until the grafting agent is completely dissolved; and then cooling to-75 ℃, sequentially adding 500g of methane chloride, 275g of isobutene and 9.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing and aging 85g of methane chloride, 1.63g of sesquiethylaluminum chloride and 0.051g of HCl for 25min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 2.2hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 5

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3500g of cyclohexane, 610g of isoprene and 1.7g of THF into the polymerization kettle, heating to 55 ℃, adding 28.5mmo1 n-butyllithium to start reaction, and reacting for 70min to form an IR chain segment; then, 1750g of cyclohexane, 390g of 1, 3-butadiene and 1.5g of THF are sequentially added into the polymerization kettle, the temperature is raised to 65 ℃, and the reaction is carried out for 60min to form an-IR-BR-chain segment; then, 3500g of cyclohexane, 410g of styrene, 250g of 1, 3-butadiene and 1.8g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 65min, so as to form an-IR-BR-SBR-chain segment; and finally, adding 31g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 23min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 42130, Mw/Mn of 5.13).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 570g of methane chloride, 580g of cyclohexane and 19.5g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 45min until the grafting agent is completely dissolved; then cooling to-77 ℃, sequentially adding 505g of methane chloride, 279g of isobutene and 11.6g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing and aging 90g of methane chloride, 1.79g of sesquiethylaluminum chloride and 0.058g of HCl for 25min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 2.5h, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 6

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3600g of cyclohexane, 630g of isoprene and 1.8g of THF into the polymerization kettle, heating to 60 ℃, adding 31.6mmo1 n-butyllithium to start reaction, and reacting for 75min to form an IR chain segment; then, 1800g of cyclohexane, 410g of 1, 3-butadiene and 1.7g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, and the reaction is carried out for 65min to form an-IR-BR-chain segment; then sequentially adding 3600g of cyclohexane, 420g of styrene, 270g of 1, 3-butadiene and 1.9g of THF into the polymerization kettle, heating to 80 ℃, and reacting for 67min to form an-IR-BR-SBR-chain segment; and finally, adding 35g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 26min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 45600 and Mw/Mn of 5.43).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 520g of methane chloride and 610g of cyclohexane and 22.5g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 48min until the grafting agent is completely dissolved; and then cooling to-80 ℃, sequentially adding 500g of methane chloride, 279g of isobutene and 12.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then adding 95g of methane chloride, 1.87g of sesquiethylaluminum chloride and 0.072g of HCl into the polymerization system for stirring and aging for 27min under the condition of-90 ℃, stirring and reacting for 2.8hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 7

(1) Preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3700g of cyclohexane, 680g of isoprene and 1.9g of THF into the polymerization kettle, heating to 60 ℃, adding 35.5mmo1 n-butyllithium for starting reaction, and reacting for 80min to form an IR chain segment; then adding 2000g of cyclohexane, 430g of 1, 3-butadiene and 1.9g of THF into the polymerization kettle in sequence, heating to 70 ℃, and reacting for 70min to form an-IR-BR-chain segment; then, 3700g of cyclohexane, 440g of styrene, 290g of 1, 3-butadiene and 2.0g of THF are sequentially added into the polymerization kettle, the temperature is raised to 80 ℃, and the reaction is carried out for 70min to form an-IR-BR-SBR-chain segment; and finally, adding 40g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 30min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n. (Mn of 49100, Mw/Mn of 5.69).

(2) Preparation of low-saturation butyl rubber: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 490g of methane chloride, 650g of cyclohexane and 24.5g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 50min until the grafting agent is completely dissolved; and then cooling to-85 ℃, sequentially adding 560g of methane chloride, 284g of isobutene and 14.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then adding 100g of methane chloride, 2.45g of sesquiethylaluminum chloride and 0.113g of HCl into the polymerization system for stirring and reacting for 3.0 hours after mixing and aging for 30min, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 1

(1) Preparation of grafting agent: the same as in example 1.

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 1, except that the amount of the grafting agent [ -IR-BR-SBR-B- ] n added during the synthesis was 3.7g, namely: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 670g of methane chloride, 460g of cyclohexane and 3.7g of [ -IR-BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 30min until the grafting agent is completely dissolved; and then cooling to-65 ℃, sequentially adding 400g of methane chloride, 255g of isobutene and 8.0g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, then mixing and aging 75g of methane chloride, 1.26g of sesquiethylaluminum chloride and 0.032g of HCl for 20min at-85 ℃, adding the mixture into the polymerization system together, stirring and reacting for 1.0hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 2

(1) Preparation of grafting agent: the other conditions were the same as in example 2 except that: no monomeric isoprene was added, i.e.: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3210g of cyclohexane and 1.2g of THF into the polymerization kettle, heating to 50 ℃, and adding 20.5mmo1 n-butyllithium; then 1600g of cyclohexane, 330g of 1, 3-butadiene and 1.0g of THF are sequentially added into a polymerization kettle, the temperature is raised to 60 ℃, and the reaction is carried out for 45min to form a-BR-chain segment; secondly, 3300g of cyclohexane, 350g of styrene, 180g of 1, 3-butadiene and 1.4g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, and the reaction is carried out for 55min to form a-BR-SBR-chain segment; and finally, adding 23g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 15min, then leading out glue solution, and carrying out wet condensation and drying to obtain the binary block copolymer grafting agent [ -BR-SBR-B- ] n. (Mn of 18230 and Mw/Mn of 3.12).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 2 except that: in the synthesis process, a grafting agent [ -IR-BR-SBR-B- ] n is not added, but the grafting agent [ -BR-SBR-B- ] n is added, namely: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 650g of methane chloride, 480g of cyclohexane and 13.8g of [ -BR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 35min until the grafting agent is completely dissolved; and then cooling to-70 ℃, sequentially adding 420g of methyl chloride, 260g of isobutene and 10.2g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-92 ℃, then mixing and aging 80g of methyl chloride, 1.38g of sesquiethyl aluminum chloride and 0.031g of HCl for 22min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 1.5hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 3

(1) Preparation of grafting agent: the other conditions were the same as in example 3 except that: without addition of monomeric 1, 3-butadiene, no-BR segment is formed, i.e.: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3300g of cyclohexane, 550g of isoprene and 1.4g of THF into the polymerization kettle, heating to 55 ℃, adding 23.5mmo1 n-butyllithium to start reaction for 60min, and forming an IR chain segment; then 1650g of cyclohexane and 1.2g of THF are sequentially added into the polymerization kettle, and the temperature is raised to 65 ℃; then, 3400g of cyclohexane, 370g of styrene, 200g of 1, 3-butadiene and 1.5g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 60min to form an-IR-SBR-chain segment; and finally, adding 25g of 1, 3-butadiene into the polymerization kettle, carrying out end-capping reaction for 17min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-SBR-B- ] n. (Mn 23100 and Mw/Mn 3.42).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 3 except that: in the synthesis process, a grafting agent [ -IR-BR-SBR-B- ] n is not added, but the grafting agent [ -IR-SBR-B- ] n is added, namely: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 630g of methane chloride, 500g of cyclohexane and 15.8g of [ -IR-SBR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 40min until the grafting agent is completely dissolved; then cooling to-75 ℃, sequentially adding 445g of methane chloride, 266g of isobutene and 12.1g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-92 ℃, then adding 85g of methane chloride, 1.48g of sesquiethylaluminum chloride and 0.042g of HCl into the polymerization system for stirring and reacting for 2.0 hours after mixing and aging for 25 minutes under the condition of-87 ℃, discharging and condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 4

(1) Preparation of grafting agent: the other conditions were the same as in example 4 except that: without the addition of the reaction monomers 1, 3-butadiene and styrene, no-SBR-segment is formed, i.e.: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3500g of cyclohexane, 580g of isoprene and 1.5g of THF into the polymerization kettle, heating to 55 ℃, adding 25.2mmo1 n-butyllithium to start reaction for 65min, and forming an IR chain segment; then, 1720g of cyclohexane, 370g of 1, 3-butadiene and 1.3g of THF are sequentially added into the polymerization kettle, the temperature is increased to 65 ℃, and the reaction is carried out for 55min to form an-IR-BR-chain segment; and finally, adding 28g of 1, 3-butadiene into the polymerization kettle, carrying out end-capping reaction for 20min, then leading out glue solution, and carrying out wet condensation and drying to obtain the binary block copolymer grafting agent [ -IR-BR-B- ] n. (Mn 18630, Mw/Mn 2.93).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 4 except that: in the synthesis process, a grafting agent [ -IR-BR-SBR-B- ] n is not added, but the grafting agent [ -IR-BR-B- ] n is added, namely: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 610g of methane chloride, 550g of cyclohexane and 17.5g of [ -IR-BR-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 42min until the grafting agent is completely dissolved; and then cooling to-75 ℃, sequentially adding 500g of methane chloride, 275g of isobutene and 9.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing and aging 85g of methane chloride, 1.63g of sesquiethylaluminum chloride and 0.051g of HCl for 25min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 2.2hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 5

(1) Preparation of grafting agent: the other conditions were the same as in example 5 except that: the reaction monomers 1, 3-butadiene are not added for the second time, and do not form an-SBR-segment but a-PS-segment, i.e.: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3500g of cyclohexane, 610g of isoprene and 1.7g of THF into the polymerization kettle, heating to 55 ℃, adding 28.5mmo1 n-butyllithium to start reaction, and reacting for 70min to form an IR chain segment; then, 1750g of cyclohexane, 390g of 1, 3-butadiene and 1.5g of THF are sequentially added into the polymerization kettle, the temperature is raised to 65 ℃, and the reaction is carried out for 60min to form an-IR-BR-chain segment; then, 3500g of cyclohexane, 410g of styrene and 1.8g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 65min, so as to form an-IR-BR-PS-chain segment; and finally, adding 31g of 1, 3-butadiene into a polymerization kettle, carrying out end-capping reaction for 23min, then leading out glue solution, and carrying out wet condensation and drying to obtain the ternary block copolymer grafting agent [ -IR-BR-PS-B- ] n. (Mn 32100 and Mw/Mn 4.05).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 5 except that: in the synthesis process, a grafting agent [ -IR-BR-SBR-B- ] n is not added, but the grafting agent [ -IR-BR-PS-B- ] n is added, namely: firstly, introducing nitrogen into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, adding 570g of methane chloride, 580g of cyclohexane and 19.5g of [ -IR-BR-PS-B- ] n grafting agent into the polymerization kettle, and stirring and dissolving for 45min until the grafting agent is completely dissolved; then cooling to-77 ℃, sequentially adding 505g of methane chloride, 279g of isobutene and 11.6g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing and aging 90g of methane chloride, 1.79g of sesquiethylaluminum chloride and 0.058g of HCl for 25min at-87 ℃, adding the mixture into the polymerization system together, stirring and reacting for 2.5h, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 6

(1) Preparation of grafting agent: the other conditions were the same as in example 6 except that: the amount of monomeric isoprene added was 50g, i.e.: firstly, a 15L stainless steel reaction kettle with a jacket is introduced with argon for 3 times of replacement, 3600g of cyclohexane, 50g of isoprene and 1.8g of THF are sequentially added into a polymerization kettle, the temperature is raised to 60 ℃, 31.6mmo1 n-butyllithium is added to startReacting for 75min to form IR₁A chain segment; then, 1800g of cyclohexane, 410g of 1, 3-butadiene and 1.7g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, and the reaction is carried out for 65min to form an-IR-BR-chain segment; then sequentially adding 3600g of cyclohexane, 420g of styrene, 270g of 1, 3-butadiene and 1.9g of THF into the polymerization kettle, heating to 80 ℃, and reacting for 67min to form an-IR-BR-SBR-chain segment; finally, 35g of 1, 3-butadiene is added into a polymerization kettle for end capping reaction for 26min, then glue solution is led out, and the ternary block copolymer grafting agent [ -IR ] is prepared by wet condensation and drying₁-BR-SBR-B-]n is the same as the formula (I). (Mn 38600 and Mw/Mn 4.26).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 6 except that: no grafting agent [ -IR-BR-SBR-B-]n, but the grafting agent [ -IR ] is added₁-BR-SBR-B-]n, namely: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 520g of methane chloride, 610g of cyclohexane and [ -IR ] are added into a polymerization kettle₁-BR-SBR-B-]n grafting agent 22.5g, stirring and dissolving for 48min until the grafting agent is completely dissolved; and then cooling to-80 ℃, sequentially adding 500g of methane chloride, 279g of isobutene and 12.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then adding 95g of methane chloride, 1.87g of sesquiethylaluminum chloride and 0.072g of HCl into the polymerization system for stirring and aging for 27min under the condition of-90 ℃, stirring and reacting for 2.8hr, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Comparative example 7

(1) Preparation of grafting agent: the other conditions were the same as in example 7 except that: the first addition of monomer 1, 3-butadiene was 30g greater than the addition of monomer isoprene, i.e.: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3700g of cyclohexane, 680g of isoprene and 1.9g of THF into the polymerization kettle, heating to 60 ℃, adding 35.5mmo1 n-butyllithium for starting reaction, and reacting for 80min to form an IR chain segment; then 2000g of cyclohexane, 30g of 1, 3-butadiene and 1.9g of THF were sequentially added to the polymerization vessel, and the temperature was raisedReacting at 70 ℃ for 70min to form-IR-BR₁-a segment; then, 3700g of cyclohexane, 440g of styrene, 290g of 1, 3-butadiene and 2.0g of THF are sequentially added into the polymerization kettle, the temperature is raised to 80 ℃, and the reaction is carried out for 70min to form an-IR-BR-SBR-chain segment; finally, 40g of 1, 3-butadiene is added into a polymerization kettle for end capping reaction for 30min, the glue solution is led out, and the ternary block copolymer grafting agent [ -IR-BR ] is prepared by wet condensation and drying₁-SBR-B-]n is the same as the formula (I). (Mn 32400 and Mw/Mn 4.09).

(2) Preparation of low-saturation butyl rubber: the other conditions were the same as in example 7 except that: no grafting agent [ -IR-BR-SBR-B-]n, but the grafting agent [ -IR-BR ] is added₁-SBR-B-]n, namely: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 490g of methane chloride, 650g of cyclohexane, [ -IR-BR ] are added into a polymerization kettle₁-SBR-B-]n grafting agent 24.5g, stirring and dissolving for 50min until the grafting agent is completely dissolved; and then cooling to-85 ℃, sequentially adding 560g of methane chloride, 284g of isobutene and 14.5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then adding 100g of methane chloride, 2.45g of sesquiethylaluminum chloride and 0.113g of HCl into the polymerization system for stirring and reacting for 3.0 hours after mixing and aging for 30min, discharging, condensing, washing and drying to obtain the low-saturation butyl rubber product. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

TABLE 1 Properties of Low-saturation butyl rubber

As can be seen from Table 1: the low-saturation butyl rubber of the invention has longer scorch time (T)₁₀) Ensures the safety of product processing and has shorter positive vulcanization time (T)₉₀) The production efficiency can be improved, and good vulcanization characteristics are reflected; meanwhile, the low-saturation butyl rubber has good air tightness, low extrusion swell ratio and high 300 percent stress at definite elongation, which shows that the low-saturation butyl rubber has the same property of good vulcanization processabilityWhile maintaining excellent physical and mechanical properties.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims

1. A preparation method of low-saturation butyl rubber is characterized by comprising the following steps:

firstly, taking styrene, butadiene and isoprene as reaction monomers, and taking alkyl lithium as an initiator to synthesize a ternary block copolymer [ -IR-BR-SBR-B- ] n;

secondly, preparing the low-saturation butyl rubber by cationic polymerization by taking the ternary block copolymer as a grafting agent and isobutene and isoprene in a catalyst system compounded by alkyl aluminum halide and protonic acid;

in the ternary block copolymer [ -IR-BR-SBR-B- ] n, IR is an isoprene homopolymer block, BR is a1, 3-butadiene homopolymer block, SBR is a styrene and butadiene random copolymer block, B is terminated butadiene, and n is 1-3.

2. The method of claim 1, wherein the preparation of the triblock copolymer [ -IR-BR-SBR-B- ] n comprises the steps of:

according to the total mass percentage of reaction monomers, firstly, under the atmosphere of inert gas, sequentially adding 200-300% of solvent, 30-50% of isoprene and 0.05-0.2% of structure regulator into a polymerization kettle, heating to 50-60 ℃, adding an initiator to start reaction, and reacting for 50-80 min to form an IR chain segment; then, sequentially adding 100-200% of solvent, 20-30% of 1, 3-butadiene and 0.01-0.1% of structure regulator into a polymerization kettle, heating to 60-70 ℃, and reacting for 40-70 min to form an-IR-BR-chain segment; secondly, sequentially adding 200-300% of solvent, 20-30% of styrene, 10-20% of butadiene and 0.05-0.15% of structure regulator into a polymerization kettle, heating to 70-80 ℃, and reacting for 50-70 min to form an-IR-BR-SBR-chain segment; finally, adding 1-3% of butadiene into a polymerization kettle for end capping, reacting until no free monomer exists, and performing wet coagulation and drying on the glue solution to obtain the ternary block copolymer grafting agent [ -IR-BR-SBR-B- ] n.

3. The process according to claim 1, wherein the process for the preparation of the low-saturation butyl rubber comprises in particular the following steps:

according to the total mass percentage of reaction monomers, firstly, 200-300 percent of diluent and solvent are added into a polymerization kettle in an inert gas atmosphere, and the volume ratio of the diluent to the solvent is 60-40: 40-60 percent of mixed solvent, 3-7 percent of grafting agent [ -IR-BR-SBR-B- ] n, and stirring and dissolving until the grafting agent is completely dissolved; and then cooling to-65 to-85 ℃, sequentially adding 100 to 200 percent of diluent, 85 to 95 percent of isobutene and 1 to 5 percent of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-100 to-90 ℃, then adding 20 to 30 percent of diluent and 0.05 to 3.0 percent of co-initiator into the polymerization system for stirring and reacting for 1.0 to 3.0 hours after mixing and aging for 20 to 30 minutes at-95 to-85 ℃, discharging and coagulating, washing and drying to obtain the low-saturation butyl rubber product.

4. The method according to claim 2, wherein the triblock copolymer [ -IR-BR-SBR-B- ] n has an isoprene content of 30% to 40%, a1, 3-butadiene content of 30% to 40%, and a styrene content of 10% to 20%.

5. The method of claim 4, wherein the triblock copolymer [ -IR-BR-SBR-B- ] n has a number average molecular weight of 20000 to 50000 and a ratio of weight average molecular weight to number average molecular weight of 4.12 to 5.71.

6. The method of claim 2, wherein the structure modifier is selected from the group consisting of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, and triethylamine.

7. The method of claim 2, wherein the initiator is selected from the group consisting of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, lithium naphthalide, cyclohexyllithium, and dodecyllithium.

8. The method of claim 3, wherein the diluent is selected from one of methyl chloride, methylene chloride, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, monofluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane.

9. The method of claim 3, wherein the co-initiator is prepared by compounding an alkyl aluminum halide and a protonic acid, and the molar ratio of the protonic acid to the alkyl aluminum halide is 0.01:1 to 0.1: 1.

10. The method of claim 9, wherein the alkyl aluminum halide is selected from at least one of diethylaluminum monochloride, diisobutylaluminum monochloride, methylaluminum dichloroide, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, n-propylaluminum dichloride, diisopropylaluminum dichloride, dimethylaluminum chloride and ethylaluminum chloride.

11. The method of claim 9, wherein the protic acid is selected from the group consisting of HCl, HF, HBr, H₂SO₄、H₂CO₃、H₃PO₄And HNO₃One kind of (1).