阅读说明：本技术 低门尼粘度、低饱和度丁基橡胶的制备方法 (Preparation method of low-Mooney viscosity and low-saturation butyl rubber ) 是由 翟云芳 于衍东 牛承祥 赵燕 杨珊珊 王在花 徐典宏 于 2020-06-24 设计创作，主要内容包括：本发明涉及一种低门尼粘度、低饱和度丁基橡胶的制备方法。该发明首先对3,9-二氧[5.5]螺环十一烷进行卤化反应,合成出一种新型四卤化物偶联剂,然后与异戊二烯、苯乙烯和丁二烯反应单体偶合制备出三元四臂星型共聚物[-IR-SBR-SB/(S→B)-B-]-(n) Y,以[-IR-SBR-SB/(S→B)-B-]-(n) Y作为接枝剂与异丁烯和异戊二烯进行阳离子接枝聚合制备出一种低门尼粘度、低饱和度丁基橡胶。该方法解决了丁基橡胶在加工过程中易出现的挤出胀大和硫化性能差的问题,实现了丁基橡胶在具有足够的生胶强度和良好的气密性的前提下,具备良好的硫化加工性,赋予了丁基橡胶物理机械性能和加工性能的平衡。(The invention relates to a preparation method of low-Mooney viscosity and low-saturation butyl rubber. The invention firstly treats 3, 9-dioxo [5.5]]Performing halogenation reaction on the spiro undecane to synthesize a novel tetrahalide coupling agent, and then coupling the coupling agent with isoprene, styrene and butadiene reaction monomers to prepare the ternary quadri-armed star copolymer [ -IR-SBR-SB/(S → B) -B-] n Y, in [ -IR-SBR-SB/(S → B) -B-] n And the Y is used as a grafting agent to carry out cationic graft polymerization with isobutene and isoprene to prepare the butyl rubber with low Mooney viscosity and low saturation. The method solves the problems of easy extrusion swelling and poor vulcanization performance of the butyl rubber in the processing process, and realizes the butyl rubberOn the premise of having enough green strength and good air tightness, the butyl rubber has good vulcanization processability, and the physical and mechanical properties and the processability of the butyl rubber are balanced.)

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

first, to 3, 9-dioxo [5.5]]Performing halogenation reaction on the spiro undecane to synthesize a tetrahalide coupling agent, and then coupling the tetrahalide coupling agent with isoprene, styrene and butadiene reaction monomers to prepare the ternary quadri-armed star copolymer [ -IR-SBR-SB/(S → B) -B-]_nY；

Secondly, under the complex catalyst system of Lewis acid and protonic acid, the ternary four-arm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nY as grafting agent and isobutylene and isoprene for cationic polymerizationObtaining the low-Mooney viscosity and low-saturation butyl rubber.

2. The method of claim 1, wherein the ternary quadriarm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nIn Y, Y is 3, 3-diethylpentane; IR is an isoprene homopolymer block; SBR is a styrene and butadiene random block copolymer with wide vinyl distribution; SB in SB/(S → B) is a random section of styrene and butadiene, (S → B) is a tapered section of styrene and butadiene; b is terminated butadiene, and n is 1-4; the general structural formula is as follows:

3. the method of claim 2, wherein the ternary quadriarm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nThe content of isoprene is 30-40%, the content of 1, 3-butadiene is 40-50%, and the content of styrene is 20-40%.

4. The method of claim 2, wherein the ternary quadriarm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nThe number average molecular weight of (A) is 10000-50000, and the ratio of the weight average molecular weight to the number average molecular weight is 9.21-11.14.

5. The method of claim 2, wherein the ternary quadriarm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nThe preparation process comprises the following steps:

a preparation of a coupling agent: according to the total mass percentage of reactants, firstly, 100-200% of deionized water, 3, 9-dioxy [5.5] spiro undecane, a halogenating agent and 1-5% of a catalyst are sequentially added into a polymerization kettle in an inert gas atmosphere, the temperature is raised to 50-80 ℃, after 1-3 hours of reaction, 20-40% of NaOH aqueous solution with the mass concentration of 10-20% is added to stop the reaction, and finally 200-300% of monochloromethane is added to extract, separate, wash and dry to prepare the coupling agent 1, 5-dihalo-3, 3-bis (2-haloethyl) pentane;

b ternary four-arm star copolymer [ -IR-SBR-SB/(S → B) -B-]_nThe preparation of (1): according to the total mass percentage of reaction monomers, firstly, under the atmosphere of inert gas, sequentially adding 200-300% of solvent, 10-20% of styrene, 20-30% of 1, 3-butadiene and 0.05-0.3% of structure regulator into a polymerization kettle, heating to 40 ℃, adding an initiator to start reaction, wherein the reaction is temperature-changing polymerization, the temperature is gradually increased from 40 ℃ to 70 ℃ within 50-80 min, the temperature rise is a continuous gradual change process, and the reaction is carried out for 50-80 min to form an SBR chain segment with wide vinyl distribution; secondly, sequentially adding 100-200% of solvent, 30-40% of isoprene and 0.05-0.2% of structure regulator into a polymerization kettle, heating to 70-80 ℃, and reacting for 40-60 min to form an-IR-SBR-chain segment; then, sequentially adding 100-200% of solvent and 0.1-0.3% of structure regulator into a polymerization kettle, heating to 70-80 ℃, stirring and mixing 10-20% of styrene and 20-30% of 1, 3-butadiene for 10-30 min, wherein the reaction is variable-speed polymerization, adding the mixture into the polymerization kettle in a continuous injection manner, reacting within 50-80 min, and carrying out initial feeding at an initial feeding speed>5.0% blend/min, forming a random, long transition-SB/(S → B) -segment; then adding 2-5% of butadiene into the polymerization kettle for end capping, and reacting until no free monomer exists; finally heating to 80-90 ℃, adding a coupling agent for coupling reaction for 70-90 min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet coagulation and drying on the glue solution to obtain the ternary four-arm star-structured copolymer grafting agent [ -IR-SBR-SB/(S → B) -B-]_nY。

6. The method of claim 5, wherein the halogenating agent is one of liquid chlorine and liquid bromine.

7. The process of claim 5, wherein the catalyst is HCl-CH₃OH, wherein the molar concentration of HCl is 0.1-0.7 mol/L.

8. The method of claim 5, 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.

9. The method of claim 5, wherein the initiator is selected from the group consisting of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, lithium naphthalide, cyclohexyllithium, and dodecyllithium.

10. The method of claim 5, wherein the coupling agent is 1, 5-dihalo-3, 3-bis (2-haloethyl) pentane, and the molar ratio of the amount of coupling agent to the amount of initiator is 3.0 to 5.0.

11. The method of claim 1, wherein the low mooney, low saturation butyl rubber is prepared by a process comprising the steps of:

according to the total mass percentage of reaction monomers, firstly, 100-200% 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 70-30: stirring and dissolving the mixed solvent and the grafting agent which are composed of 30-70% for 20-30 min until the grafting agent is completely dissolved; and then cooling to-75 to-85 ℃, sequentially adding 100 to 200 percent of diluent, 85 to 95 percent of isobutene and 1 to 3 percent of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-100 to-90 ℃, then adding 20 to 40 percent of diluent and 0.05 to 2.0 percent of co-initiator into the polymerization system for stirring and reacting for 2.0 to 5.0 hours after mixing and aging for 20 to 30 minutes at-85 to-95 ℃, discharging and coagulating, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation.

12. The method of claim 11, wherein the diluent is selected from one of methyl chloride, methylene chloride, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, monofluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane.

13. The method of claim 11, wherein the co-initiator is formulated from an alkyl aluminum halide and a protic acid, and the molar ratio of protic acid to alkyl aluminum halide is from 0.01:1 to 0.1: 1.

14. The method of claim 13, 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.

15. The method of claim 13, wherein the protic acid is selected from the group consisting of HCl, HF, HBr, H₂SO₄、H₂CO₃、H₃PO₄And HNO₃One kind of (1).

Technical Field

The invention relates to a preparation method of low-Mooney-viscosity and low-saturation butyl rubber, in particular to a method for preparing low-Mooney-viscosity and low-saturation butyl rubber by cationic polymerization of isoprene, butadiene and styrene ternary four-arm star-shaped 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. In addition, with the addition of the three-dimensional star-shaped structure grafting agent, the disorder of molecular chain segments of the butyl rubber is increased in the graft polymerization process, the regularity of molecular chains is deteriorated, and the molecular weight distribution is obviously widened, so that the butyl rubber can obtain low Mooney viscosity and good viscoelastic property, the energy consumption in the processing and mixing process can be effectively reduced, and the filler is dispersed more uniformly. Therefore, the development of the butyl rubber with the Mooney viscosity and the low saturation can solve the contradiction between the strength of the butyl rubber and the extrusion swelling in the processing process, and realize the key point of the balance between the physical and mechanical properties and the processing performance 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; in the second step, a first portion of the butyl rubber slurry is fedIn the second loop reactor zone, after the polymerization reaction is carried out for 5-10min at the temperature of-92 ℃ to-90 ℃ and the pressure of 0.1 to 0.2Mpa, the butyl rubber slurry with broad/bimodal molecular weight distribution is finally obtained; 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 mixture of a major amount of an internalized dialkylaluminum, a minor amount of a monoalkylaluminum dihalide, and a minor amount of an aluminoxane to provide 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 method of using a metal of group II or group III of the periodic Table of the elementsThe halides being combined with tetrahalides of metals of group IV of the periodic Table of the elements, e.g. by reacting AICl₃And 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 reagent, and is used for initiating vinyl monomers to perform homopolymerization, block copolymerization, star polymerization and graft copolymerization, wherein 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-Mooney viscosity and low-saturation butyl rubber. The invention firstly treats 3, 9-dioxo [5.5]]Performing halogenation reaction on the spiro undecane to synthesize a novel tetrahalide coupling agent, and then coupling the coupling agent with isoprene, styrene and butadiene reaction monomers to prepare the ternary quadri-armed star copolymer [ -IR-SBR-SB/(S → B) -B-]_nAnd Y. Under the complex catalyst system of Lewis acid and protonic acid, the catalyst is prepared by [ -IR-SBR-SB/(S → B) -B-]_nAnd carrying out cationic polymerization on the Y serving as a grafting agent, isobutene and isoprene to prepare the butyl rubber with low Mooney viscosity and low saturation. According to the method, the degree of vulcanization is increased and the processing mixing performance is improved by improving the unsaturation degree and reducing the Mooney viscosity of the butyl rubber, the problems of extrusion swelling and poor vulcanization performance of the butyl rubber during processing are solved, the butyl rubber has good vulcanization processability on the premise of sufficient green rubber strength and good air tightness, and the balance between the physical mechanical property and the processing performance of the butyl rubber is endowed.

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

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

(1) preparation of grafting agent:

a preparation of a coupling agent: according to the total mass percentage of reactants, firstly, 100-200% of deionized water, 3, 9-dioxo [5.5] spiro undecane, a halogenating agent and 1-5% of a catalyst are sequentially added into a polymerization kettle in an inert gas atmosphere, the temperature is raised to 50-80 ℃, after 1-3 hours of reaction, 20-40% of NaOH aqueous solution with the mass concentration of 10-20% is added to stop the reaction, and finally, 200-300% of monochloromethane is added to extract, separate, wash and dry the obtained product to obtain the coupling agent 1, 5-dihalo-3, 3-bis (2-haloethyl) pentane (the yield is 85-95%).

b preparation of grafting agent: based on the total mass of the reaction monomers, firstly, under the atmosphere of inert gas, 200 to 300 percent of solvent, 10 to 20 percent of styrene and 1 percent of styrene are sequentially added into a polymerization kettle,20-30% of 3-butadiene and 0.05-0.3% of structure regulator, heating to 40 ℃, adding an initiator to start reaction, wherein the reaction is variable temperature polymerization, the temperature is gradually increased from 40 ℃ to 70 ℃ within 50-80 min, the temperature increase is a continuous gradual change process, and the reaction is carried out for 50-80 min to form an SBR chain segment with wide vinyl distribution; secondly, sequentially adding 100-200% of solvent, 30-40% of isoprene and 0.05-0.2% of structure regulator into a polymerization kettle, heating to 70-80 ℃, and reacting for 40-60 min to form an-IR-SBR-chain segment; then sequentially adding 100-200% of solvent and 0.1-0.3% of structure regulator into a polymerization kettle, heating to 70-80 ℃, stirring and mixing 10-20% of styrene and 20-30% of 1, 3-butadiene for 10-30 min, wherein the reaction is variable-speed polymerization, adding the mixture into the polymerization kettle in a continuous injection manner, reacting within 50-80 min, and carrying out initial feeding at an initial feeding speed>5.0% of mixture/min, the extent of the decrease in the feed rate depending on the reaction time, forming a random, long transition-SB/(S → B) -chain segment; then adding 2-5% of butadiene into the polymerization kettle for end capping, and reacting for 20-40 min until no free monomer exists; finally heating to 80-90 ℃, adding a coupling agent for coupling reaction for 70-90 min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet coagulation and drying on the glue solution to obtain the ternary four-arm star-structured copolymer grafting agent [ -IR-SBR-SB/(S → B) -B-]_nY。

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, adding 100-200% of a diluent and a solvent in the following ratio by weight in an inert gas atmosphere: the V ratio is 70-30: 30-70 percent of mixed solvent and 2-7 percent of grafting agent, stirring and dissolving for 20-30 min until the grafting agent is completely dissolved; and then cooling to-75 to-85 ℃, sequentially adding 100 to 200 percent of diluent, 85 to 95 percent of isobutene and 1 to 3 percent of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-100 to-90 ℃, then adding 20 to 40 percent of diluent and 0.05 to 2.0 percent of co-initiator into the polymerization system for stirring and reacting for 2.0 to 5.0 hours after mixing and aging for 20 to 30 minutes at-85 to-95 ℃, discharging and coagulating, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation.

The grafting agent is a binary four-arm star-shaped copolymer [ -IR-SBR-SB/(S → B) -B-]_nY, the structural general formula is shown as formula I:

wherein Y is 3, 3-diethylpentane; IR is an isoprene homopolymer block; SBR is a styrene and butadiene random block copolymer with wide vinyl distribution; SB in SB/(S → B) is a random section of styrene and butadiene, (S → B) is a tapered section of styrene and butadiene; b is terminated butadiene, and n is 1-4; the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nIn Y, the content of isoprene is 30-40%, the content of 1, 3-butadiene is 40-50%, and the content of styrene is 20-40%; the number average molecular weight (Mn) is 10000-50000, and the molecular weight distribution (Mw/Mn) is 9.21-11.14.

The halogenating agent is one of liquid chlorine and liquid bromine, preferably liquid bromine, the dosage of the halogenating agent is determined according to the dosage of the 3, 9-dioxo [5.5] spiroundecane, and the molar ratio of the dosage of the liquid bromine to the 3, 9-dioxo [5.5] spiroundecane is 4.5-6.5.

The catalyst of the invention is HCl-CH₃A mixed aqueous solution of OH, wherein the molar concentration of HCl is: 0.1 to 0.7 mol/L.

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 coupling agent used in the invention is 1, 5-dihalo-3, 3-di (2-haloethyl) pentane, the dosage of the coupling agent is determined according to the amount of an initiator, a star polymer with a four-arm structure is coupled by an excessive coupling agent, and the molar ratio of the dosage of the coupling agent to the total organic lithium is 3.0-5.0.

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 one of methyl chloride, methylene chloride, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, monofluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride and fluorobutane, preferably methyl chloride.

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 0.1-3.0%, 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 treats 3, 9-dioxo [5.5]]Performing halogenation reaction on spiro undecane to synthesize a novel coupling agent 1, 5-dibromo-3, 3-di (2-bromoethyl) pentane, and then coupling the novel coupling agent with isoprene, styrene and butadiene reaction monomers to obtain a ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (see FIG. 1), and finally [ -IR-SBR-SB/(S → B) -B-]_nAnd preparing the butyl rubber with low Mooney viscosity and low saturation by cationic polymerization of the Y serving as a grafting agent, isobutene and isoprene in a catalyst system compounded by alkyl aluminum halide and protonic acid.

The copolymer [ -IR-SBR-SB/(S → B) -B-]_nY, combining chain segments of three different microstructures on a macromolecular chain, coupling the chain segments by a novel coupling agent 1, 5-dibromo-3, 3-di (2-bromoethyl) pentane to form a four-arm star structure, so that the performances of the different chain segments and the characteristics of the four-arm structure are organically combined together and play a role in a synergistic manner, and the polymerization reaction speed is continuously changed by utilizing temperature-changing polymerization and speed-changing polymerization, so that a-SBR-chain segment with wide vinyl distribution and a-SB/(S → B) -chain segment with random and long gradual change sections are obtained, the regularity of the molecular chain can be obviously damaged in the grafting process of the butyl rubber, the molecular weight distribution of the butyl rubber is obviously widened, and the Mooney viscosity is greatly reduced; the four-arm structure can also obviously widen the molecular weight distribution of the butyl rubber and reduce the Mooney viscosity, so that the Mooney viscosity of the butyl rubber can be obviously reduced under the synergistic action of the three aspects, the processing and mixing performance is improved, the energy consumption in the processing and mixing process is reduced, and the excellent processing performance is obtained; simultaneously, a certain amount of double bonds can be introduced into the saturated molecular main chain of the butyl rubber by vinyl in the-IR-chain segment, -SBR-chain segment and-SB/(S → B) -chain segment, so that the required vulcanization capacity is provided, the vulcanization degree is increased, and the problems of extrusion swelling and product size stability of the butyl rubber in the processing process are solvedPoor in the properties. In addition, the SBR-chain segment and the SB/(S → B) -chain segment contain a certain amount of benzene rings, and the benzene rings have high rigidity and steric hindrance, so that high strength and air tightness can be obtained, and the influence of strength and air tightness reduction caused by broadening of molecular weight distribution of butyl rubber is compensated.

Therefore, the invention solves the problem of contradiction relation between the processability and the physical and mechanical properties of the butyl rubber by the design of the ternary four-arm star structure, and finally realizes the balance between the vulcanization characteristic and the processability of the butyl rubber, and the strength and the air tightness. The preparation method provided by the invention has the characteristics of short process flow, controllable molecular weight of the product, designable molecular structure, suitability for industrial production and the like.

Drawings

FIG. 1 is [ -IR-SBR-SB/(S → B) -B-]_nAnd Y is a synthetic route map.

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

3, 9-dioxo [5.5] spiroundecane of 99% purity from Hubei Ferry 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 Mooney viscosity: the measurement was carried out by using a Mooney viscometer model GT-7080-S2 manufactured by Taiwan high-speed railway.

The Mooney relaxation time, determined with a large rotor at 125 ℃ C (1+8) according to the method of GB/T1232.1-2000, is 120 s.

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:

a preparation of a coupling agent: firstly, in a 4L stainless steel polymerization kettle with a jacket, introducing argon gas for 3 times, and adding 500g of deionized water and 70g of 3, 9-dioxygen [5.5] into the polymerization kettle in sequence]Spiroundecane, 350g of liquid bromine, 19g of HCl-CH₃OH solution (HCl molar concentration: 0.7mol/L), heating to 55 ℃, reacting for 3.0hr, adding 320g of NaOH aqueous solution with mass concentration of 15% to terminate the reaction, and finally adding 900g of monochloromethane to extract, separate, wash and dry to obtain the coupling agent 1, 5-dibromo-3, 3 bis (2-bromoethyl) pentane (yield 94%).

b preparation of grafting agent: firstly, a 15L stainless steel reaction kettle with a jacket is introduced with argon for 3 times of replacement, 3150g of cyclohexane, 160g of styrene, 310g of 1, 3-butadiene and 1.5g of THF are sequentially added into a polymerization kettle, the temperature is raised to 40 ℃, and 20.5mmo1 n-butyllithium is addedStarting the reaction, namely carrying out temperature-changing polymerization for 50min, gradually increasing the temperature from 40 ℃ to 70 ℃ within 50min, and increasing the temperature at the speed of 0.6 ℃/min to form an SBR chain segment with wide vinyl distribution; secondly, sequentially adding 1550g of cyclohexane, 450g of isoprene and 0.9g of THF into the polymerization kettle, heating to 70 ℃, and reacting for 40min to form an-IR-SBR-chain segment; then, 1520g of cyclohexane and 1.3g of THF are sequentially added into the polymerization kettle, the temperature is raised to 70 ℃, then 160g of styrene and 310g of 1, 3-butadiene are stirred and mixed for 10min, within 50min, the initial feeding speed is 45g of mixture/min, the feeding speed is reduced by 3g of mixture per minute, and a random and long gradual change section-SB/(S → B) -chain segment is formed; then adding 30g of butadiene into the polymerization kettle for end-capping reaction for 20min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 80 ℃, adding 65.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane, reacting for 70min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 12500, Mw/Mn 9.26).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 590g of monochloromethane and 280g of cyclohexane are added into the polymerization kettle [ -IR-SBR-SB/(S → B) -B-]_n10.5g of Y grafting agent is stirred and dissolved for 20min until the grafting agent is completely dissolved; and then cooling to-75 ℃, sequentially adding 500g of methane chloride, 420g of isobutene and 5g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, then mixing 80g of methane chloride, 0.85g of aluminum sesquiethylate chloride and 0.015g of HCl at-85 ℃, aging for 20min, then adding the mixture into the polymerization system together, stirring and reacting for 2.0hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 2

(1) Preparation of grafting agent:

a preparation of a coupling agent: the same as in example 1.

b preparation of grafting agent: firstly, the sleeve is provided with a jacketIntroducing argon into a 15L stainless steel reaction kettle, replacing for 3 times, sequentially adding 3250g of cyclohexane, 180g of styrene, 330g of 1, 3-butadiene and 1.6g of THF into the polymerization kettle, heating to 40 ℃, adding 23.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 50min, the temperature gradually rises from 40 ℃ to 70 ℃ within 50min, and the heating speed is 0.6 ℃/min, so as to form an SBR chain segment with wide vinyl distribution; secondly, 1600g of cyclohexane, 480g of isoprene and 1.0g of THF are sequentially added into a polymerization kettle, the temperature is raised to 72 ℃, and the reaction is carried out for 45min to form an-IR-SBR-chain segment; secondly, adding 1620g of cyclohexane and 1.5g of THF into the polymerization kettle in sequence, heating to 70 ℃, then stirring and mixing 180g of styrene and 340g of 1, 3-butadiene for 15min, and within 50min, reducing the initial feeding speed by 45g of mixture/min to 3g of mixture per minute to form a random and long gradual change section-SB/(S → B) -chain segment; then 35g of butadiene is added into the polymerization kettle for end-capping reaction for 23min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 82 ℃, adding 80.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane, reacting for 75min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 23800, Mw/Mn 9.62).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, nitrogen is introduced into a 4L stainless steel reaction kettle with a jacket for 3 times of replacement, 570g of monochloromethane and 300g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n14.5g of Y grafting agent is stirred and dissolved for 22min until the grafting agent is completely dissolved; then cooling to-78 ℃, sequentially adding 510g of methane chloride, 425g of isobutene and 8g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, then mixing 85g of methane chloride, 1.05g of aluminum sesquiethylate chloride and 0.029g of HCl at-85 ℃, aging for 23min, then adding the mixture into the polymerization system together, stirring and reacting for 3.0hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 3

(1) Preparation of grafting agent:

a preparation of a coupling agent: the same as in example 1.

b preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3350g of cyclohexane, 200g of styrene, 350g of 1, 3-butadiene and 1.7g of THF into the polymerization kettle, heating to 40 ℃, adding 26.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 60min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 60min, and the heating speed is 0.5 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; then, 1700g of cyclohexane, 500g of isoprene and 1.1g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 50min to form a-IR-SBR-chain segment; then adding 1700g of cyclohexane and 1.6g of THF into the polymerization kettle in sequence, heating to 75 ℃, then stirring and mixing 200g of styrene and 370g of 1, 3-butadiene for 20min, and within 70min, reducing the initial feeding speed by 50g of mixture/min and the feeding speed by 4g of mixture per minute to form a random and long gradual change section-SB/(S → B) -chain segment; then 39g of butadiene was added to the polymerization vessel to carry out an end-capping reaction for 30min, thereby forming [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 85 ℃, adding 90.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane, reacting for 80min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 33100, Mw/Mn 9.86).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 550g of monochloromethane and 320g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n18.6g of Y grafting agent is stirred and dissolved for 25min until the grafting agent is completely dissolved; cooling to-80 deg.C, sequentially adding 520g of methyl chloride, 430g of isobutylene and 10g of isoprene, stirring and mixing until the temperature of the polymerization system is reduced to-93 deg.C, mixing 85g of methyl chloride, 1.59g of sesquiethylaluminum chloride and 0.042g of HCl at-87 deg.C, aging for 25min, adding into the polymerization system, stirring and reacting for 3.5hr, discharging, coagulating, washingAnd drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 4

(1) Preparation of grafting agent:

a preparation of a coupling agent: the same as in example 1.

b preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3550g of cyclohexane, 230g of styrene, 370g of 1, 3-butadiene and 1.8g of THF into the polymerization kettle, heating to 40 ℃, adding 28.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 60min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 60min, and the heating speed is 0.5 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; then, 1800g of cyclohexane, 520g of isoprene and 1.2g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 53min to form a-IR-SBR-chain segment; secondly, adding 1800g of cyclohexane and 1.7g of THF into a polymerization kettle in sequence, heating to 75 ℃, then stirring and mixing 230g of styrene and 390g of 1, 3-butadiene for 25min, and within 70min, reducing the mixture by 4g per minute at an initial feeding speed of 50 g/min to form a random and long gradual change section-SB/(S → B) -chain segment; then 43g of butadiene is added into the polymerization kettle for an end-capping reaction for 33min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 87 ℃, adding 100.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane, reacting for 82min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 40600, Mw/Mn 10.36).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 520g of monochloromethane and 350g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n20.5g of Y grafting agent is stirred and dissolved for 27min until the grafting agent is completely dissolved; then cooling to-83 ℃, adding 530g of methane chloride, 440g of isobutene and 12g of isoprene in sequence, stirring and mixing until the temperature of a polymerization system is reduced to-93 DEG CThen 90g of methane chloride, 2.05g of aluminum sesquiethylate chloride and 0.058g of HCl are mixed and aged for 26min at the temperature of minus 87 ℃, then the mixture is added into a polymerization system together to be stirred and reacted for 4.3hr, and then the discharged material is coagulated, washed and dried to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 5

(1) Preparation of grafting agent:

a preparation of a coupling agent: the same as in example 1.

b preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3750g of cyclohexane, 260g of styrene, 390g of 1, 3-butadiene and 2.0g of THF into the polymerization kettle, heating to 40 ℃, adding 30.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 80min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 80min, and the heating speed is 0.4 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; then 1900g of cyclohexane, 550g of isoprene and 1.4g of THF are sequentially added into the polymerization kettle, the temperature is raised to 77 ℃, and the reaction is carried out for 55min to form a-IR-SBR-chain segment; then adding 1900g of cyclohexane and 1.9g of THF into the polymerization kettle in sequence, heating to 78 ℃, then stirring and mixing 260g of styrene and 410g of 1, 3-butadiene for 28min, and within 80min, reducing the initial feeding speed by 40g of mixture/min and the feeding speed by 2g of mixture per minute to form a random and long gradual change section-SB/(S → B) -chain segment; then 47g of butadiene is added into the polymerization kettle for end-capping reaction for 36min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 87 ℃, adding 120.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane, reacting for 85min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 43600, Mw/Mn 10.62).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 480g of methane chloride, 400g of cyclohexane, [ -IR-SBR-SB/(S → B) -B-]_n22.5g of a Y grafting agent,stirring to dissolve for 28min until the grafting agent is completely dissolved; and then cooling to-85 ℃, sequentially adding 550g of methane chloride, 445g of isobutene and 15g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then mixing 90g of methane chloride, 2.25g of aluminum sesquiethylate chloride and 0.073g of HCl at-87 ℃, aging for 25min, then adding the mixture into the polymerization system together, stirring and reacting for 4.7hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

Example 6

(1) Preparation of grafting agent:

a preparation of a coupling agent: firstly, in a 4L stainless steel polymerization kettle with a jacket, introducing argon for 4 times of replacement, and then adding 600g of deionized water and 65g of 3, 9-dioxygen [5.5] into the polymerization kettle in sequence]Spiroundecane, 300g of liquid chlorine, 30g of HCl-CH₃OH solution (HCl molar concentration: 0.7mol/L), heating to 80 deg.C, reacting for 3.0hr, adding 300g NaOH aqueous solution with mass concentration of 20% to terminate the reaction, and finally adding 900g methane chloride to extract, separate, wash and dry to obtain the coupling agent 1, 5-dichloro-3, 3 bis (2-chloroethyl) pentane (yield 95%).

b preparation of grafting agent: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 4 times, sequentially adding 3850g of cyclohexane, 290g of styrene, 420g of 1, 3-butadiene and 2.2g of THF into the polymerization kettle, heating to 40 ℃, adding 33.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 80min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 80min, and the heating speed is 0.4 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; then adding 1900g of cyclohexane, 550g of isoprene and 1.5g of THF into the polymerization kettle in sequence, heating to 80 ℃, and reacting for 60min to form an-IR-SBR-chain segment; secondly, sequentially adding 2000g of cyclohexane and 2.2g of THF into the polymerization kettle, heating to 80 ℃, then stirring and mixing 280g of styrene and 430g of 1, 3-butadiene for 30min, and within 80min, reducing the mixture by 2g per minute at an initial feeding speed of 40 g/min to form a random and long gradual change section-SB/(S → B) -chain segment; then 52g of butadiene was further charged into the polymerization vesselAfter 40min of end-capping reaction, [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 90 ℃, adding 150.5mmo11, 5-dichloro-3, 3-di (2-chloroethyl) pentane, reacting for 90min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -IR-SBR-SB/(S → B) -B-]_nY (Mn 49200, Mw/Mn 11.02).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 400g of monochloromethane and 460g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n27.5g of Y grafting agent is stirred and dissolved for 30min until the grafting agent is completely dissolved; and then cooling to-85 ℃, sequentially adding 580g of methane chloride, 460g of isobutene and 20g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then mixing 95g of methane chloride, 2.85g of aluminum sesquiethylate chloride and 0.095g of HCl at-95 ℃, aging for 30min, then adding the mixture into the polymerization system together, stirring and reacting for 5.0hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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:

a preparation of a coupling agent: the same as in example 1.

b preparation of grafting agent: the same as in example 1.

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 1 except that [ -IR-SBR-SB/(S → B) -B-]_nThe amount of Y grafting agent added was 4.0g, i.e.: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 590g of monochloromethane and 280g of cyclohexane are added into the polymerization kettle [ -IR-SBR-SB/(S → B) -B-]_n4.0g of Y grafting agent is stirred and dissolved for 20min until the grafting agent is completely dissolved; then cooling to-75 ℃, adding 500g of methane chloride, 420g of isobutene and 5g of isoprene in sequence, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, and then chlorinating 80g of methane chloride and sesquiethyl0.85g of aluminum and 0.015g of HCl0.015g are mixed and aged for 20min at the temperature of-85 ℃, then are added into a polymerization system together, stirred and reacted for 2.0hr, and then the materials are discharged for coagulation, washed and dried to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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: in the synthesis process, a coupling agent 1, 5-dibromo-3, 3 di (2-bromoethyl) pentane is not added, namely: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3250g of cyclohexane, 180g of styrene, 330g of 1, 3-butadiene and 1.6g of THF into the polymerization kettle, heating to 40 ℃, adding 23.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 50min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 50min, and the heating speed is 0.6 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; secondly, 1600g of cyclohexane, 480g of isoprene and 1.0g of THF are sequentially added into a polymerization kettle, the temperature is raised to 72 ℃, and the reaction is carried out for 45min to form an-IR-SBR-chain segment; secondly, 1620g of cyclohexane and 1.5g of THF are sequentially added into a polymerization kettle, the temperature is raised to 70 ℃, then 180g of styrene and 340g of 1, 3-butadiene are stirred and mixed for 15min, within 50min, the initial feeding speed is 45g of mixture/min, the feeding speed is reduced by 3g of mixture per minute, and a random and long gradual change section-SB/(S → B) -chain segment is formed; then 35g of butadiene is added into the polymerization kettle for end-capping reaction for 23min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 82 ℃, reacting for 75min, and obtaining the ternary single-arm polymer [ -IR-SBR-SB/(S → B) -B-]_n(Mn 14800, Mw/Mn 3.25).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 2 except that: no [ -IR-SBR-SB/(S → B) -B-]_nY grafting agent, but adding [ -IR-SBR-SB/(S → B) -B-]_nGrafting agents, namely: firstly, nitrogen is introduced into a 4L stainless steel reaction kettle with a jacket for 3 times of replacement, 570g of monochloromethane and 300g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n14.5g of grafting agent is stirred and dissolved for 22min until the grafting agent is completely dissolved; then cooling to-78 ℃, sequentially adding 510g of methane chloride, 425g of isobutene and 8g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-90 ℃, then mixing 85g of methane chloride, 1.05g of aluminum sesquiethylate chloride and 0.029g of HCl at-85 ℃, aging for 23min, then adding the mixture into the polymerization system together, stirring and reacting for 3.0hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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: in the synthesis process, a coupling agent 1, 5-dibromo-3, 3 bis (2-bromoethyl) pentane is not added, but a conventional coupling agent tin tetrachloride is added, namely: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 3 times, sequentially adding 3350g of cyclohexane, 200g of styrene, 350g of 1, 3-butadiene and 1.7g of THF into the polymerization kettle, heating to 40 ℃, adding 26.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 60min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 60min, and the heating speed is 0.5 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; then, 1700g of cyclohexane, 500g of isoprene and 1.1g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 50min to form a-IR-SBR-chain segment; then adding 1700g of cyclohexane and 1.6g of THF into the polymerization kettle in sequence, heating to 75 ℃, then stirring and mixing 200g of styrene and 370g of 1, 3-butadiene for 20min, and within 70min, reducing the initial feeding speed by 50g of mixture/min and the feeding speed by 4g of mixture per minute to form a random and long gradual change section-SB/(S → B) -chain segment; then 39g of butadiene was added to the polymerization vessel to carry out an end-capping reaction for 30min, thereby forming [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 85 ℃, adding 90.5mmo1 stannic chloride, reacting for 80min, treating the coupled reaction mixture with water after the reaction is finished, and carrying out wet coagulation and drying on the glue solution to obtain the ternary quadriarmed star polymer [ -IR-SBR-SB/(S → B) -B-]_n Y₁(Mn 29100, Mw/Mn 6.02).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 3 except that: no [ -IR-SBR-SB/(S → B) -B-]_nY grafting agent, but adding [ -IR-SBR-SB/(S → B) -B-]_n Y₁Grafting agents, namely: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 550g of monochloromethane and 320g of cyclohexane are added into the polymerization kettle, [ -IR-SBR-SB/(S → B) -B-]_n Y₁Stirring and dissolving 18.6g of grafting agent for 25min until the grafting agent is completely dissolved; and then cooling to-80 ℃, sequentially adding 520g of methane chloride, 430g of isobutene and 10g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing 85g of methane chloride, 1.59g of aluminum sesquiethylate chloride and 0.042g of HCl at-87 ℃, aging for 25min, then adding the mixture into the polymerization system together, stirring and reacting for 3.5hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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:

a preparation of a coupling agent: the same as in example 4.

b preparation of grafting agent: the other conditions were the same as in example 4 except that: the SBR chain segment synthesis does not adopt temperature-variable polymerization, but reacts under the constant temperature condition of 40 ℃ to form SBR₁A segment, namely: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for 3 times of replacement, sequentially adding 3550g of cyclohexane, 230g of styrene, 370g of 1, 3-butadiene and 1.8g of THF into the polymerization kettle, heating to 40 ℃, adding 28.5mmo1 n-butyllithium to start reaction, and reacting for 60min to form SBR₁A chain segment; then, 1800g of cyclohexane, 520g of isoprene and 1.2g of THF are sequentially added into a polymerization kettle, the temperature is raised to 75 ℃, and the reaction is carried out for 53min to form a-IR-SBR-chain segment; then 1800g of cyclohexane and 1.7g of THF are added into the polymerization kettle in sequence, the temperature is raised to 75 ℃, then 230g of styrene and 390g of 1, 3-butadiene are stirred and mixed for 25min, within 70min, the initial feeding speed is 50g of mixture/min, the feeding speed is reduced by 4g of mixture per minute, and random mixture is formedLong transition-SB/(S → B) -segment; then 43g of butadiene is added into the polymerization kettle again, and after the end capping reaction is carried out for 33min, the [ -IR-SBR is formed₁-SB/(S→B)-B-]_nA chain segment; finally, the temperature is raised to 87 ℃, 100.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane is added for reaction for 82min, the reaction mixture after the coupling is treated by water after the reaction is finished, and the glue solution is coagulated and dried by a wet method to prepare the ternary four-arm star polymer [ -IR-SBR₁-SB/(S→B)-B-]_nY (Mn 38600, Mw/Mn 5.32).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 4 except that: no [ -IR-SBR-SB/(S → B) -B-]_nY grafting agent, but adding [ -IR-SBR₁-SB/(S→B)-B-]_nY grafting agent, namely: firstly, nitrogen gas is introduced into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, and 520g of methane chloride and 350g of cyclohexane are added into a polymerization kettle [ -IR-SBR ]₁-SB/(S→B)-B-]_n20.5g of Y grafting agent is stirred and dissolved for 27min until the grafting agent is completely dissolved; and then cooling to-83 ℃, sequentially adding 530g of methane chloride, 440g of isobutene and 12g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-93 ℃, then mixing 90g of methane chloride, 2.05g of aluminum sesquiethylate chloride and 0.058g of HCl at-87 ℃, aging for 26min, then adding the mixture into the polymerization system together, stirring and reacting for 4.3hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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:

a preparation of a coupling agent: the same as in example 5.

b preparation of grafting agent: the other conditions were the same as in example 5 except that: the synthesis of the-SB/(S → B) -segment does not employ a variable-speed polymerization, but is added at one time to form a random-segment SBR₂Namely: firstly, a 15L stainless steel reaction kettle with a jacket is introduced with argon for 3 times, 3750g of cyclohexane, 260g of styrene, 390g of 1, 3-butadiene and 2.0g of THF are sequentially added into a polymerization kettle, and the temperature is raised to 40 DEG CAdding 30.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization and is carried out for 80min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 80min, and the temperature-increasing speed is 0.4 ℃/min, so as to form an SBR chain segment with wide vinyl distribution; then 1900g of cyclohexane, 550g of isoprene and 1.4g of THF are sequentially added into the polymerization kettle, the temperature is raised to 77 ℃, and the reaction is carried out for 55min to form a-IR-SBR-chain segment; then 1900g of cyclohexane, 1.9g of THF, 260g of styrene and 410g of 1, 3-butadiene are sequentially added into the polymerization kettle, the temperature is raised to 78 ℃, and the reaction is carried out for 80min to form the random SBR₂A chain segment; then 47g of butadiene is added into the polymerization kettle for end-capping reaction for 36min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally, the temperature is raised to 87 ℃, 120.5mmo 11, 5-dibromo-3, 3-di (2-bromoethyl) pentane is added for reaction for 85min, the reaction mixture after the coupling is treated by water after the reaction is finished, and the glue solution is coagulated and dried by a wet method to prepare the ternary four-arm star polymer [ -IR-SBR₂-B-]_nY (Mn of 39600, Mw/Mn of 4.54).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 5 except that: no [ -IR-SBR-SB/(S → B) -B-]_nY grafting agent, but adding [ -IR-SBR₂-B-]_nY grafting agent, namely: firstly, nitrogen is introduced into a 4L stainless steel reaction kettle with a jacket for replacement for 3 times, 480g of methane chloride, 400g of cyclohexane and [ -IR-SBR ] are added into a polymerization kettle₂-B-]_n22.5g of Y grafting agent is stirred and dissolved for 28min until the grafting agent is completely dissolved; and then cooling to-85 ℃, sequentially adding 550g of methane chloride, 445g of isobutene and 15g of isoprene, stirring and mixing until the temperature of a polymerization system is reduced to-95 ℃, then mixing 90g of methane chloride, 2.25g of aluminum sesquiethylate chloride and 0.073g of HCl at-87 ℃, aging for 25min, then adding the mixture into the polymerization system together, stirring and reacting for 4.7hr, discharging, condensing, washing and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. 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:

a preparation of a coupling agent: the same as in example 6.

b preparation of grafting agent: the other conditions were the same as in example 6 except that: during the synthesis of the grafting agent, no isoprene monomer is added, and no-IR-segment is formed, namely: firstly, introducing argon into a 15L stainless steel reaction kettle with a jacket for replacement for 4 times, sequentially adding 3850g of cyclohexane, 290g of styrene, 420g of 1, 3-butadiene and 2.2g of THF into the polymerization kettle, heating to 40 ℃, adding 33.5mmo1 n-butyllithium to start reaction, wherein the reaction is temperature-changing polymerization, the reaction lasts for 80min, the temperature is gradually increased from 40 ℃ to 70 ℃ within 80min, and the heating speed is 0.4 ℃/min, so that an SBR chain segment with wide vinyl distribution is formed; secondly, sequentially adding 2000g of cyclohexane and 2.2g of THF into the polymerization kettle, heating to 80 ℃, then stirring and mixing 280g of styrene and 430g of 1, 3-butadiene for 30min, and within 80min, reducing the mixture by 2g per minute at an initial feeding speed of 40 g/min to form a random and long gradual change section-SB/(S → B) -chain segment; then 52g of butadiene is added into the polymerization kettle for end capping reaction for 40min to form [ -IR-SBR-SB/(S → B) -B-]_nA chain segment; finally heating to 90 ℃, adding 150.5mmo11, 5-dichloro-3, 3-di (2-chloroethyl) pentane, reacting for 90min, treating the coupled reaction mixture with water after the reaction is finished, and performing wet condensation and drying on the glue solution to obtain the ternary four-arm star polymer [ -SBR-SB/(S → B) -B-]_nY (Mn 31200, Mw/Mn 8.05).

(2) Preparation of low Mooney viscosity, low saturation butyl rubber: the other conditions were the same as in example 6 except that: no [ -IR-SBR-SB/(S → B) -B-]_nY grafting agent, but adding [ -SBR-SB/(S → B) -B-]_nY grafting agent, namely: firstly, in a 4L stainless steel reaction kettle with a jacket, nitrogen is introduced for 3 times for replacement, 400g of methane chloride and 460g of cyclohexane are added into the polymerization kettle, [ -SBR-SB/(S → B) -B-]_n27.5g of Y grafting agent is stirred and dissolved for 30min until the grafting agent is completely dissolved; then cooling to-85 deg.C, adding 580g of methane chloride, 460g of isobutene and 20g of isoprene in turn, stirring and mixing until the temperature of the polymerization system is reduced to-95 deg.C, then mixing 95g of methane chloride, 2.85g of sesquiethylaluminum chloride and 0.095g of HCl at-95 deg.CAging for 30min, adding into the polymerization system, stirring, reacting for 5.0hr, discharging, coagulating, washing, and drying to obtain the butyl rubber product with low Mooney viscosity and low saturation. Sampling and analyzing: standard test specimens were prepared and the test properties are shown in Table 1.

TABLE 1 Properties of Low Mooney, Low saturation butyl rubber

As can be seen from Table 1: the low Mooney, low saturation butyl rubber of the present invention has a Mooney viscosity of less than 39 and an unsaturation of greater than 2.6 mol%, a scorch time (T₁₀) Long, positive cure time (T)₉₀) Short, and shows good vulcanization characteristic and mixing processability; meanwhile, the low-Mooney-viscosity low-saturation butyl rubber has good air tightness, low extrusion expansion ratio and high 300% stress at definite elongation, which shows that the low-Mooney-viscosity low-saturation butyl rubber has good vulcanization characteristic and mixing processability while 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.