Polypolar symmetric-structure ether regulator, liquid polybutadiene rubber, and preparation method and application of polypolar symmetric-structure ether regulator and liquid polybutadiene rubber

Abstract

The invention provides a multi-polar symmetric-structure ether regulator and liquid polybutadiene rubber as well as a preparation method and application of the multi-polar symmetric-structure ether regulator and the liquid polybutadiene rubber. The polypolar symmetric-structure ether regulator has a structure shown in a formula I. The preparation method of the liquid polybutadiene rubber comprises the following steps: firstly, carrying out anionic polymerization on 1, 3-butadiene and isoprene serving as reaction monomers to obtain a macromolecular branching agent; then, tetrahydro-2-furan alkanol and a diisocyanate compound are used for synthesizing a multi-polarity symmetric structure ether conditioning agent; and finally, carrying out anionic solution polymerization reaction on the macromolecular branching agent, the multi-polar symmetric structure ether regulator and a 1, 3-butadiene monomer, and adding the macromolecular branching agent in the rear stage of the synthesis process to obtain the liquid polybutadiene rubber. The liquid polybutadiene rubber prepared by the preparation method has the characteristics of high vinyl content and high molecular weight.

Description

Technical Field

[0001] This invention belongs to the field of synthetic rubber technology, specifically relating to a multipolar symmetric ether modifier and liquid polybutadiene rubber, as well as their preparation method and application. Background Technology

[0002] With the development of modern communication, liquid polybutadiene rubber has gradually begun to be used as an adhesive for circuit boards. Since modern communication signals are transmitted at high frequency and high speed, circuit boards generate a lot of heat during use. This requires various materials to have both heat aging resistance and excellent adhesion. In the case of liquid polybutadiene rubber, this means that it is required to have a high molecular weight and a high content of vinyl structure (1,2-structure) to facilitate curing reaction with other resins, glass fibers, etc. to form a cross-linked structure, thereby improving the overall strength and adhesion of the circuit board.

[0003] However, liquid polybutadiene rubber is a viscous, flowable polymer formed by the polymerization of 1,3-butadiene monomers, resulting in a number-average molecular weight of 500-10,000. Typically, the polymerization of 1,3-butadiene in anionic polymerization is predominantly trans-1,4-structure polymerization (over 60%), resulting in low molecular weight and a low 1,2-structure content, which cannot meet the requirements of high adhesion and high reactivity in high-end electronic materials. To obtain high molecular weight polybutadiene liquid rubber with a high vinyl structure (1,2-structure) content, it is necessary to achieve controllable polymer chain growth and microstructure. Many factors influence polymer chain growth and microstructure, such as the type, concentration, and amount of initiator, and the effects of solvents and polar additives. Among these factors, the type and amount of initiator and the method of adding polar modifiers are among the most important methods for synthesizing high molecular weight polymers with different microstructures.

[0004] However, high molecular weight also brings a serious drawback to liquid polybutadiene rubber. When the number-average molecular weight of liquid polybutadiene rubber exceeds 10,000, its polymer form changes from a viscous, flowable state to a waxy, non-flowable state, which affects its coating and use on circuit boards. Therefore, the development of high vinyl content, high molecular weight polybutadiene liquid rubber has broad industrial application value and prospects in the field of electronic communications.

[0005] In the prior art, research on high vinyl content and high molecular weight liquid polybutadiene rubber mainly focuses on its preparation by adding small molecule modifiers. CN114106228A discloses a method for preparing liquid butadiene polymer, in which 1,3-butadiene monomer is continuously added to a reactor in the presence of an initiator and a composite structure modifier in a non-polar hydrocarbon solvent at a polymerization temperature below 0°C to carry out anionic solution polymerization reaction, thereby obtaining a liquid butadiene polymer. CN113461837A provides a method for preparing low cis, high vinyl end-hydroxyl polybutadiene rubber, by adding a mixture of tetrahydrofuran and N,N-dimethylformamide, a mixture of tetrahydrofuran and tetramethylethylenediamine, a mixture of tetrahydrofuran and 2,2-di(2-tetrahydrofuranyl)propane, or a mixture of 2,2-di(2-tetrahydrofuranyl)propane and tetrahydrofurfuryl ethyl ether to prepare a high vinyl structure liquid polybutadiene rubber. CN1089272A discloses a method for controlling the vinyl content in butadiene homopolymers and copolymers, which uses a combination of diethylene glycol dimethyl ether and tetrahydrofuran as regulators to control the vinyl content in polybutadiene rubber. CN117327219A provides a method for preparing high-vinyl liquid polybutadiene rubber, which uses the structure regulator 2,2-bis(2-tetrahydrofuranyl) to prepare liquid polybutadiene rubber with a high vinyl structure.

[0006] While the use of small-molecule organic structure modifiers can increase the vinyl content in liquid polybutadiene rubber to some extent, these methods still have limitations. For example, the liquid polybutadiene rubber has a low molecular weight, high modification cost, and insignificant modification effect, failing to meet the requirements of high adhesion and high reactivity for high-end electronic materials. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a multipolar symmetrical ether modifier, a liquid polybutadiene rubber, a preparation method thereof, and its applications. The liquid polybutadiene rubber prepared by this method exhibits high vinyl content and high molecular weight.

[0008] To achieve the above objectives, the present invention provides a multipolar symmetrical ether modifier having the structure shown in Formula I:

[0009]

[0010] In Formula I, R1 is selected from C1-C15 alkylene groups and their derivatives; R2 is selected from C1-C4 straight-chain alkylene groups.

[0011] According to a specific embodiment of the present invention, preferably, in Formula I, R1 is selected from C1-C9 alkylene groups and their derivatives, C6-C15 aryl groups and their derivatives, and C5-C14 alicyclic groups and their derivatives.

[0012] According to a specific embodiment of the present invention, preferably, in Formula I, R1 is selected from C5-C9 alkylene groups and their derivatives, C6-C13 aryl groups and their derivatives, and C10-C13 alicyclic groups and their derivatives.

[0013] The present invention also provides a method for preparing the above-mentioned multipolar symmetric structure ether modifier, which includes the following steps: mixing a third solvent, tetrahydro-2-furanol and a diisocyanate compound, heating to 70-85°C, adding a catalyst to carry out the reaction, and after the reaction is completed, cooling, rotary evaporation and drying to obtain the multipolar symmetric structure ether modifier.

[0014] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric ether modifier, the mass ratio of the third solvent, the reactant and the catalyst is (100-200):100:(0.1-0.4); the reactant is tetrahydro-2-furanol and diisocyanate compound, and the mass ratio of tetrahydro-2-furanol and diisocyanate compound is (60-70):(30-40) based on 100 parts of the mass of the reactant.

[0015] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric structure ether modifier, the stirring speed of the reaction is 300-500 rpm; the reaction time is 3.5-5.0 hours.

[0016] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric structure ether modifier, the diisocyanate compound includes one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, 4,4-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and lysine diisocyanate.

[0017] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric structure ether modifier, the diisocyanate compound includes one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, and 4,4-diisocyanate dicyclohexylmethane, more preferably hexamethylene diisocyanate.

[0018] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric structure ether modifier, the tetrahydro-2-furanol includes one or more combinations of tetrahydro-2-furanol, tetrahydro-2-furanethanol, tetrahydro-2-furanpropanol, and tetrahydro-2-furanbutanol, more preferably tetrahydro-2-furanpropanol.

[0019] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric structure ether modifier, the catalyst includes organometallic catalysts, tertiary amine catalysts, organic base catalysts, or organic acid catalysts, etc., for example, selected from one or more combinations of triphenylphosphine, tributylphosphine, triethylphosphine, triphenylbismuth, dibutyltin diacetate, dibutyltin dilaurate, lead naphthenate, zinc naphthenate, cobalt naphthenate, methyldiethanolamine, and dimethylethanolamine, more preferably triphenylphosphine.

[0020] According to a specific embodiment of the present invention, preferably, in the preparation method of the multipolar symmetric ether modifier, the third solvent includes one or a combination of two or more of N,N-dimethylformamide, dimethyl sulfoxide, chlorobenzene, chloromethane, dichloromethane, 1,4-dioxane, and tetrahydrofuran.

[0021] This invention also provides a method for preparing liquid polybutadiene rubber, which includes the following steps:

[0022] Step 1: Preparation of macromolecular branching agent: Mix the first solvent, 1,3-butadiene, and structure regulator, heat the mixture, add an initiator to react, and when the conversion rate of 1,3-butadiene reaches 98%-100%, add isoprene to react. When the conversion rate of isoprene reaches 100%, export the slurry, coagulate, wash, and dry to obtain the macromolecular branching agent.

[0023] Step 2: Preparation of liquid polybutadiene rubber: The second solvent, 1,3-butadiene, and a multipolar symmetric ether regulator are mixed. After cooling, an initiator is added to carry out the reaction. When the conversion rate of 1,3-butadiene reaches 89%-92%, the macromolecular branching agent obtained in Step 1 is added, and the reaction continues until the conversion rate of 1,3-butadiene reaches 95%-97%. Then, a terminator is added to terminate the polymerization. After coagulation, washing, and drying, the liquid polybutadiene rubber is obtained.

[0024] In this invention, the multipolar symmetric ether modifier does not participate in the actual copolymerization reaction during the preparation of liquid polybutadiene rubber. In actual industrial production of liquid polybutadiene rubber, this multipolar symmetric ether modifier is easily separated from the solvent, which can be recycled. The system of initiator (e.g., a hydrocarbon-based monolithium compound) and multipolar symmetric ether modifier in step two initiates the anionic polymerization reaction of 1,3-butadiene. By rationally setting the proportions of each component in this system, especially the ratio of the multipolar symmetric ether modifier to the initiator, the vinyl content in the polybutadiene structure can be precisely controlled.

[0025] According to a specific embodiment of the present invention, preferably, in step one, the mass ratio of 1,3-butadiene to isoprene is (68-83):(17-32) when the sum of the masses of 1,3-butadiene and isoprene is 100 parts.

[0026] According to a specific embodiment of the present invention, preferably, in step one, the mass ratio of 1,3-butadiene to isoprene is (70-80):(20-30) calculated based on the sum of the masses of 1,3-butadiene and isoprene being 100 parts.

[0027] According to a specific embodiment of the present invention, preferably, in step two, the mass ratio of 1,3-butadiene to macromolecular branching agent is 100:(4-8).

[0028] According to a specific embodiment of the present invention, preferably, in step two, the mass ratio of 1,3-butadiene to macromolecular branching agent is 100:(5-7).

[0029] According to a specific embodiment of the present invention, preferably, in step two, the molar ratio of the multipolar symmetric structure ether modifier to the initiator calculated as Li is (1.8-3.7):1.

[0030] According to a specific embodiment of the present invention, preferably, in step two, the molar ratio of the multipolar symmetric structure ether modifier to the initiator calculated as Li is (2.0-3.5):1.

[0031] According to a specific embodiment of the present invention, preferably, the reaction conditions in step one satisfy any one or a combination of two or more of the following (1)-(5):

[0032] (1) The mass ratio of the first solvent to the monomer raw material is (400-500):100, and the monomer raw material is 1,3-butadiene and isoprene;

[0033] (2) The molar ratio of the structure modifier to the initiator is (1.5-3.0):1;

[0034] (3) Add the initiator after heating to 55-60℃; the stirring speed of the reaction is 500-600 rpm;

[0035] (4) The macromolecular branching agent is a block copolymer of 1,3-butadiene and isoprene, with the structure [-BR-IR-]. n Where: BR is a 1,3-butadiene homopolymer; IR is an isoprene homopolymer, n≥2;

[0036] (5) The number average molecular weight of the macromolecular branching agent is 700-900.

[0037] The macromolecular branching agent is added in the later stage of the reaction during the preparation of liquid polybutadiene rubber. By controlling the molecular weight, molecular structure, amount added, and timing of addition of the macromolecular branching agent, the growth of branches and the number of branching points are reduced, thereby achieving the goal of low branching in the final stage of liquid polybutadiene rubber. This increases the intermolecular distance and weakens the intermolecular interaction, thereby reducing the viscosity of the branched polymer. This solves the problem that the increased viscosity of liquid polybutadiene rubber due to the increase in molecular weight affects its coatability.

[0038] According to a specific embodiment of the present invention, preferably, the reaction conditions in step two satisfy any one or a combination of two or more of the following (1)-(3):

[0039] (1) The mass ratio of the second solvent, 1,3-butadiene, macromolecular branching agent and terminating agent is (800-1000):100:(5-7):(2.0-7.0), more preferably (800-1000):100:(5-7):(3.0-5.0);

[0040] (2) After cooling to -10 to -1℃, add the initiator; the stirring speed of the reaction is 600-700 rpm;

[0041] (3) The coagulation operation is as follows: add water and acid to the reaction solution, stir and let stand to separate the water phase and oil phase, and perform vacuum distillation on the oil phase to obtain the liquid polybutadiene rubber.

[0042] In step two of this invention, the types of water and acid used in the coagulation process are well known to those skilled in the art, and their addition amounts are within the conventional addition range in the prior art. This invention does not impose any particular limitations on them. Washing and drying (e.g., vacuum drying) can be reasonably set according to the conditions in the conventional liquid polybutadiene rubber preparation process. This invention does not impose any particular limitations on them.

[0043] According to a specific embodiment of the present invention, preferably, the reaction conditions of the method for preparing the liquid polybutadiene rubber satisfy any one or a combination of two or more of the following (1)-(6):

[0044] (1) In step one, the structure modifier is a polar organic compound, including one or more of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, and triethylamine, more preferably tetrahydrofuran;

[0045] (2) In step one, the first solvent includes one or more of pentane, hexane, octane and heptane, more preferably hexane;

[0046] (3) In step two, the second solvent is a hydrocarbon solvent, including cycloalkanes and aromatic solvents, such as one or more combinations of cyclopentane, cyclohexane, benzene, toluene, xylene and ethylbenzene, more preferably cyclohexane;

[0047] (4) In steps one and two, the initiator is a hydrocarbon monolithium compound RLi, wherein R is selected from C1-C20 saturated aliphatic hydrocarbon groups, C3-C20 alicyclic hydrocarbon groups, and C6-C20 aromatic hydrocarbon groups.

[0048] (5) In step two, the terminating agent includes one or more of methanol, ethanol, propanol, butanol, isobutanol, and pentanol;

[0049] (6) Both steps one and two are carried out in an oxygen-free, water-free and inert gas environment. The inert gas is nitrogen or a gas of a group 0 element in the periodic table other than radon, and more preferably argon. The number of inert gas replacements is 3-5 times.

[0050] According to a specific embodiment of the present invention, preferably, the 1,3-butadiene is of polymerization grade purity (purity ≥ 97%), and the isoprene is of polymerization grade purity (purity ≥ 98%).

[0051] According to a specific embodiment of the present invention, preferably, the initiator is selected from one or more combinations of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium, more preferably n-butyllithium.

[0052] According to a specific embodiment of the present invention, preferably, the amount of initiator added is determined by the molecular weight of the target liquid polybutadiene, for example, by calculating the amount of the initiator n-butyllithium using the following formula:

[0053] Molar amount of n-butyllithium (mol) = Total mass of gel m (g) / Molecular weight M (g / mol);

[0054] The total mass of the adhesive refers to the expected prepared mass of the target liquid polybutadiene, and the molecular weight refers to the molecular weight of the target liquid polybutadiene.

[0055] According to a specific embodiment of the present invention, the preparation method of the above-mentioned liquid polybutadiene rubber includes the following specific steps:

[0056] (I) Preparation of macromolecular branching agent: Based on a total mass of 100 parts of 1,3-butadiene and isoprene monomers, first, in a jacketed 4L stainless steel reactor, argon gas is purged 3-5 times. Then, 400-500 parts of hexane, 70-80 parts of 1,3-butadiene, and a structure modifier are added sequentially to the reactor. The mixture is stirred and heated to 55-60℃, followed by the addition of n-butyllithium. When the conversion rate of 1,3-butadiene monomer reaches 100%, 20-30 parts of isoprene are added to the reactor. When the isoprene conversion rate reaches 100%, the slurry is discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymers;

[0057] (II) Preparation of multipolar symmetric structure ether regulator: Taking 100 parts of total mass of tetrahydro-2-furan alcohol and diisocyanate, firstly, in a 4L stainless steel reactor with a jacket, argon gas is introduced to purge 3-5 times. Then, tetrahydrofuran, 60-70 parts of tetrahydro-2-furan alcohol and 30-40 parts of diisocyanate are added to the reactor in sequence. The mixture is stirred and heated to 70-85℃. Then, a catalyst is added to react. After the reaction is completed, the reaction solution is cooled to room temperature. The reaction solution is then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric structure ether regulator.

[0058] (III) Preparation of liquid polybutadiene rubber: In a 10L stainless steel reactor with a jacket, an inert gas is introduced for purging. 800-1000 parts of cyclohexane, 100 parts of 1,3-butadiene, and 5-7 parts of a multipolar symmetric ether regulator are added sequentially to the reactor. The mixture is stirred and cooled to -10 to -1℃. Then, n-butyllithium is added to react. When the conversion rate reaches 89%-92%, a macromolecular branching agent is added to continue the reaction until the conversion rate reaches 95%-97%. 3.0-5.0 parts of ethanol are added to terminate the polymerization. The mixture is then coagulated, washed, and vacuum dried to obtain liquid polybutadiene rubber.

[0059] According to a specific embodiment of the present invention, preferably, the reaction vessel can be a loop reactor or a batch reactor, more preferably a batch reactor.

[0060] The present invention also provides a liquid polybutadiene rubber, which is prepared by the above-described preparation method.

[0061] According to a specific embodiment of the present invention, preferably, the liquid polybutadiene rubber has a 1,2-vinyl structure content of 72%-75%; a number-average molecular weight ≥12000; and a dynamic viscosity at 45°C ≤2700 poise.

[0062] According to a specific embodiment of the present invention, preferably, the number-average molecular weight of the liquid polybutadiene rubber is 12,000-14,000; and the dynamic viscosity at 45°C is 2,500-2,700 poise.

[0063] This invention also provides the application of the above-mentioned liquid polybutadiene rubber in the preparation of circuit boards. The steps are as follows: under the action of a crosslinking agent or curing agent, the liquid polybutadiene rubber is cured and crosslinked with resin or glass fiber, which can effectively improve the overall strength and toughness of the circuit board, greatly improve the quality of the circuit board product, and can be widely used in the electronics industry.

[0064] The preparation method of this invention utilizes macromolecular branching agents and multipolar symmetrical ether modifiers to control the dynamic viscosity and vinyl content of liquid polybutadiene rubber, resulting in high-vinyl, high-molecular-weight liquid polybutadiene rubber with a number-average molecular weight (Mn) ≥ 12000, a dynamic viscosity at 45°C ≤ 2700 poise, and a 1,2-structure content of 72%-75%. This solves the problems of the polymer morphology of liquid polybutadiene rubber changing from a viscous, flowable state to a waxy, non-flowable state due to excessively high molecular weight, as well as the low 1,2-structure content. This is beneficial for the coating and use of circuit boards, effectively improving the strength and toughness of the subsequently prepared circuit boards. It can meet the requirements of the high-end electronics industry for high reactivity, adhesion, and coatability of liquid polybutadiene rubber, greatly improving the quality of circuit board products. This invention has the following beneficial effects:

[0065] (1) This invention synthesizes a macromolecular branching agent, [-BR-IR-]n block copolymer, using anionic polymerization with 1,3-butadiene and isoprene. The -IR- segments in this branching agent contain a certain amount of side methyl groups, which further helps to increase the intermolecular distance and weaken the intermolecular interactions. Simultaneously, the macromolecular branching agent is added later in the synthesis of liquid polybutadiene rubber to achieve low branching of the final chain segments, reducing the number of branching points and lowering the probability of entanglement of the branches themselves. Under the synergistic effect of these two aspects, the viscosity of liquid polybutadiene rubber can be significantly reduced, thus avoiding the problem of increased viscosity due to increased molecular weight. This solves the contradiction between high molecular weight and low viscosity in liquid polybutadiene rubber, achieving a balance between the two. This balance allows high molecular weight liquid polybutadiene rubber to achieve high adhesion while maintaining good flowability, which is beneficial for coating and use on circuit boards and can meet the coating requirements of high-end electronic circuit boards.

[0066] (2) This invention utilizes tetrahydro-2-furanol and diisocyanate to synthesize a multipolar symmetrical ether regulator. This regulator fully exerts the multipolar "group effect" in the anionic polymerization of conjugated diene (1,3-butadiene), thereby improving the ability of the Lewis base of the multipolar group to regulate the 1,2-structure content of the conjugated diene and promoting the reaction to move towards the π-allyl lithium structure. In other words, the 1,2-addition product will increase accordingly. It can prepare a high vinyl, high molecular weight liquid polybutadiene rubber liquid with a vinyl (1,2-structure) content of 72%-75%, which can meet the requirements of high reactivity for high-end electronic circuit boards.

[0067] (3) The preparation method of the macromolecular branching agent provided by the present invention has the characteristics of short process flow, controllable molecular weight, and good product performance stability;

[0068] (4) The preparation method of the high vinyl and high molecular weight liquid polybutadiene rubber of the present invention has the characteristics of being green and environmentally friendly, having a low amount of macromolecular branching agent added, having a significant modification effect, having a low modification cost, and being suitable for industrial production. Attached Figure Description

[0069] Figure 1 The infrared spectrum of the multipolar symmetric ether modifier obtained in Example 1. Detailed Implementation

[0070] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0071] Unless otherwise specified, the term "parts" in this invention refers to parts by mass, and the term "ratio" refers to a mass ratio.

[0072] 1. Source of raw materials:

[0073]

[0074]

[0075] All other reagents are commercially available industrial products.

[0076] 2. Analysis and testing methods:

[0077] (1) Determination of molecular weight: Molecular weight was determined using a Waters 2414 gel permeation chromatography (GPC) system (USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / ml, the injection volume was 50 μL, the elution time was 40 min, and the flow rate was 1 ml·min⁻¹. 1 .

[0078] (2) 1 Determination of vinyl groups by 1H NMR: using proton nuclear magnetic resonance spectroscopy (NMR) 1 The vinyl content of high-vinyl, high-molecular-weight liquid polybutadiene rubber was analyzed and characterized by 1H NMR. The main methods are as follows: 1. The product was completely dissolved in deuterated chloroform to prepare a 1H NMR sample; 2. The 1H NMR spectrum was measured and analyzed.

[0079] (3) Dynamic viscosity test at 45℃: determined according to standard GB / T 10247-2008.

[0080] Example 1

[0081] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0082] (I) Preparation of macromolecular branching agents:

[0083] First, in a jacketed 4L stainless steel reactor, argon gas was purged three times. Then, 2000g of hexane, 400g of 1,3-butadiene, and 1080mmol of THF were added sequentially to the polymerization reactor. The mixture was stirred at 500rpm and heated to 55℃. Then, 720mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 100g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the conversion rate of isoprene reached 100%, the slurry was exported, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]n block copolymer (Mn is 700, n≥2).

[0084] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0085] First, argon gas was purged three times in a jacketed 4L stainless steel polymerization reactor. Then, 500g of tetrahydrofuran, 300g of tetrahydro-2-furanpropanol, and 200g of hexamethylene diisocyanate were added sequentially to the reactor. The mixture was stirred at 300 rpm and heated to 70°C. Then, 0.5g of triphenylphosphine was added and the reaction proceeded for 3.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature (25°C). The multipolar symmetric ether modifier was obtained by rotary evaporation and vacuum drying. Its infrared spectrum is shown below. Figure 1 At wavenumbers of 860-850 cm⁻¹ 1 Characteristic peaks of epoxy groups appear at 1750-1730 cm⁻¹; at wavenumbers of 1750-1730 cm⁻¹ 1 A sharp absorption peak appeared at the ester group; at wavenumbers of 3400-3300 cm⁻¹. 1 A sharp absorption peak appeared at the amine group;

[0086] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0087] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged three times. Then, 4000g of cyclohexane, 500g of 1,3-butadiene, and 84mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 600rpm and cooled to -1℃. Then, 42mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 89%, 25g of the [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the 1,3-butadiene conversion reached 95%. Then, 15g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 2L of demineralized water and 5mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 30 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and then the oil phase was washed three times with 5L of demineralized water. The resulting oil phase was subjected to vacuum distillation and then vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0088] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0089] Example 2

[0090] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0091] (I) Preparation of macromolecular branching agents:

[0092] First, in a jacketed 4L stainless steel reactor, argon gas was purged three times. Then, 2100g of hexane, 390g of 1,3-butadiene, and 1310mmol of THF were added sequentially to the polymerization reactor. The mixture was stirred at 520rpm and heated to 56℃. Then, 690mmol of n-butyllithium was added to react and form BR segments. When the 1,3-butadiene monomer conversion reached 100%, 110g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer (Mn is 740, n≥2);

[0093] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0094] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged three times. Then, 600g of tetrahydrofuran, 310g of tetrahydro-2-furanpropanol and 190g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 310 rpm and heated to 72°C. Then, 0.7g of triphenylphosphine was added and reacted for 3.7 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0095] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0096] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged three times. Then, 4200g of cyclohexane, 500g of 1,3-butadiene, and 94mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 630rpm and cooled to -2℃. Then, 41mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 89.7%, 27g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the 1,3-butadiene conversion reached 95.4%. Then, 17g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 2.2L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 33 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 5.5L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0097] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0098] Example 3

[0099] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0100] (I) Preparation of macromolecular branching agents:

[0101] First, in a jacketed 4L stainless steel reactor, argon gas was purged four times. Then, 2200g hexane, 380g 1,3-butadiene, and 1440mmol THF were added sequentially to the polymerization reactor, and the mixture was stirred at 550rpm. When the temperature reached 57℃, 660mmol n-butyllithium was added to react and form BR segments. When the 1,3-butadiene monomer conversion reached 100%, 120g isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer (Mn is 790, n≥2);

[0102] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0103] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged four times. Then, 700g of tetrahydrofuran, 320g of tetrahydro-2-furanpropanol and 180g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 320 rpm and heated to 73°C. Then, 1.0g of triphenylphosphine was added and reacted for 4.0 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0104] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0105] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged four times. Then, 4500g of cyclohexane, 500g of 1,3-butadiene, and 106mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 650rpm and cooled to -5℃. Then, 40mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 91.1%, 29g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the 1,3-butadiene conversion reached 96.1%. Then, 19g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 2.5L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0106] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0107] Example 4

[0108] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0109] (I) Preparation of macromolecular branching agents:

[0110] First, in a jacketed 4L stainless steel reactor, argon gas was purged four times. Then, 2300g of hexane, 370g of 1,3-butadiene, and 1560mmol of THF were added sequentially to the polymerization reactor, followed by stirring at 570rpm. When the temperature reached 58℃, 630mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 130g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion rate reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer (Mn is 820, n≥2);

[0111] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0112] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged four times. Then, 800g of tetrahydrofuran, 330g of tetrahydro-2-furanpropanol and 170g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 325 rpm and heated to 76°C. Then, 1.2g of triphenylphosphine was added and reacted for 4.1 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0113] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0114] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged four times. Then, 4800g of cyclohexane, 500g of 1,3-butadiene, and 116mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 670rpm and cooled to -7℃. Then, 39mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 91.5%, 31g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. nThe block copolymer was reacted until the 1,3-butadiene conversion reached 96.6%. Then, 21g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0115] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0116] Example 5

[0117] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0118] (I) Preparation of macromolecular branching agents:

[0119] First, in a jacketed 4L stainless steel reactor, argon gas was purged five times. Then, 2400g of hexane, 360g of 1,3-butadiene, and 1680mmol of THF were added sequentially to the polymerization reactor, and the mixture was stirred at 580rpm. When the temperature reached 59℃, 600mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 140g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion rate reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer (Mn is 860, n≥2);

[0120] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0121] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged four times. Then, 850g of tetrahydrofuran, 335g of tetrahydro-2-furanpropanol and 165g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 330 rpm and heated to 79°C. Then, 1.5g of triphenylphosphine was added and reacted for 4.3 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0122] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0123] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged five times. Then, 4900g of cyclohexane, 500g of 1,3-butadiene, and 123mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 680rpm and cooled to -8℃. Then, 38mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 91.8%, 33g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the 1,3-butadiene conversion reached 96.7%. Then, 24g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0124] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0125] Example 6

[0126] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0127] (I) Preparation of macromolecular branching agents:

[0128] First, in a jacketed 4L stainless steel reactor, argon gas was purged five times. Then, 2500g of hexane, 350g of 1,3-butadiene, and 1710mmol of THF were added sequentially to the polymerization reactor, and the mixture was stirred at 600rpm. When the temperature reached 60℃, 570mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 150g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion rate reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymers (Mn is 900, n≥2);

[0129] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0130] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged five times. Then, 950g of tetrahydrofuran, 345g of tetrahydro-2-furanpropanol and 155g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 340 rpm and heated to 82°C. Then, 1.8g of triphenylphosphine was added and reacted for 4.6 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0131] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0132] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged five times. Then, 5000g of cyclohexane, 500g of 1,3-butadiene, and 130mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 700rpm and cooled to -10℃. Then, 37mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 92.0%, 35g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the conversion of 1,3-butadiene reached 97.0%. Then, 25g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0133] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0134] Example 7

[0135] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0136] (a) Preparation of macromolecular branching agents: Same as in Example 6;

[0137] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0138] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged five times. Then, 950g of tetrahydrofuran, 345g of tetrahydro-2-furan ethanol and 155g of diphenylmethane diisocyanate (MDI) were added to the polymerization reactor in sequence. The mixture was stirred at 340 rpm and heated to 82°C. Then, 1.8g of triphenylphosphine was added and reacted for 4.6 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0139] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0140] In a jacketed 10L stainless steel polymerization reactor, argon gas was purged five times. Then, 5000g of cyclohexane, 500g of 1,3-butadiene, and 130mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 700rpm and cooled to -10℃. Then, 37mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 92.0%, 35g of the macromolecular branching agent [-BR-IR-] obtained in step (I) was added. n The block copolymer was reacted until the conversion of 1,3-butadiene reached 97.0%. Then, 25g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0141] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0142] Example 8

[0143] This embodiment provides a high-vinyl, high-molecular-weight liquid polybutadiene rubber, which is prepared by the following steps:

[0144] (a) Preparation of macromolecular branching agents: Same as in Example 5;

[0145] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0146] First, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket and purged four times. Then, 850g of tetrahydrofuran, 340g of tetrahydro-2-furanbutanol and 160g of 4,4-diisocyanate dicyclohexylmethane were added to the polymerization reactor in sequence. The mixture was stirred at 335 rpm and heated to 80°C. Then, 1.7g of triphenylphosphine was added and reacted for 4.5 hours. After the reaction was completed, the reaction solution was cooled to room temperature and then dried by rotary evaporation and vacuum drying to obtain a multipolar symmetric ether modifier.

[0147] (III) Preparation of high-vinyl, high-molecular-weight liquid polybutadiene rubber:

[0148] In a 10L stainless steel polymerization reactor with a jacket, argon gas was purged five times. Then, 4900g of cyclohexane and 500g of [unspecified substance] were added sequentially to the polymerization reactor. 1,3-Butadiene and 128 mmol of a multipolar symmetric ether modifier were stirred at 690 rpm and cooled to -9°C. Then, 38 mmol of n-butyllithium was added. When the conversion of 1,3-butadiene reached 91.9%, 33 g of the macromolecular branching agent [-BR-IR-]n block copolymer obtained in step (I) was added. The reaction continued until the conversion of 1,3-butadiene reached 96.8%. Then, 24 g of ethanol was added to terminate the polymerization reaction, and a polymerization reaction mixture was obtained. Subsequently, coagulation was carried out. 3.0 L of demineralized water and 6 mL of sulfuric acid (molar concentration of 0.5 mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0 L of demineralized water. The obtained oil phase was subjected to vacuum distillation and then vacuum dried at 70°C to obtain high vinyl, high molecular weight liquid polybutadiene rubber.

[0149] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0150] Comparative Example 1

[0151] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0152] (I) Preparation of macromolecular branching agents:

[0153] Other conditions were the same as in Example 1, except that the amount of n-butyllithium added in the preparation of the macromolecular branching agent was 460 mmol. Specifically: First, in a 4L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2000g of hexane, 400g of 1,3-butadiene, and 1080 mmol of THF were added sequentially to the polymerization reactor. The mixture was stirred at 500 rpm and heated to 55°C. Then, 460 mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 100g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion rate reached 100%, the slurry was exported, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer a (Mn is 1120, n≥2);

[0154] (II) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 1;

[0155] (III) Preparation of liquid polybutadiene rubber:

[0156] Other conditions were the same as in Example 1, except that a macromolecular branching agent [-BR-IR-] was added during the preparation of the liquid polybutadiene rubber. n Block copolymer a, with an addition amount of 25g, is prepared as follows: In a jacketed 10L stainless steel polymerization reactor, argon gas is purged three times. Then, 4000g of cyclohexane, 500g of 1,3-butadiene, and 84mmol of a multipolar symmetric ether modifier are added sequentially. The mixture is stirred at 600rpm and cooled to -1℃. Then, 42mmol of n-butyllithium is added. When the conversion rate of 1,3-butadiene reaches 89%, 25g of the macromolecular branching agent [-BR-IR-] is added. n Block copolymer a was reacted until the conversion of 1,3-butadiene reached 95%. Then, 15g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out. 2L of demineralized water and 5mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 30 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and then the oil phase was washed three times with 5L of demineralized water. The resulting oil phase was subjected to vacuum distillation and then vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0157] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0158] Comparative Example 2

[0159] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0160] (I) Preparation of macromolecular branching agents:

[0161] Other conditions were the same as in Example 2, except that the amount of n-butyllithium added in the preparation of the macromolecular branching agent was 830 mmol. Specifically: First, in a 4L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2100g of hexane, 390g of 1,3-butadiene, and 1310 mmol of THF were added sequentially to the polymerization reactor. The mixture was stirred at 520 rpm and heated to 56°C. Then, 830 mmol of n-butyllithium was added to react and form BR segments. When the conversion rate of 1,3-butadiene monomer reached 100%, 110g of isoprene was added to the polymerization reactor to react and form -IR-BR- segments. When the isoprene conversion rate reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-IR-]. n Block copolymer b (Mn is 620, n≥2);

[0162] (II) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 2;

[0163] (III) Preparation of liquid polybutadiene rubber:

[0164] Other conditions were the same as in Example 2, except that a macromolecular branching agent [-BR-IR-] was added during the preparation of the liquid polybutadiene rubber. n Block copolymer b, with an addition amount of 27g, is prepared as follows: In a jacketed 10L stainless steel polymerization reactor, argon gas is purged three times. Then, 4200g of cyclohexane, 500g of 1,3-butadiene, and 94mmol of a multipolar symmetric ether modifier are added sequentially. The mixture is stirred at 630rpm and cooled to -2℃. Then, 41mmol of n-butyllithium is added. When the conversion rate of 1,3-butadiene reaches 89.7%, 27g of the macromolecular branching agent [-BR-IR-] is added. n Block copolymer b was reacted until the conversion of 1,3-butadiene reached 95.4%. Then, 17g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 2.2L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 33 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 5.5L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0165] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0166] Comparative Example 3

[0167] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0168] (I) Preparation of macromolecular branching agents:

[0169] Other conditions were the same as in Example 3, except that isoprene was not added during the preparation of the macromolecular branching agent. Specifically: First, argon gas was purged four times in a jacketed 4L stainless steel reactor. Then, 2200g of hexane, 380g of 1,3-butadiene, and 1440mmol of THF were added sequentially to the polymerization reactor, and the mixture was stirred at 550rpm. When the temperature reached 57°C, 660mmol of n-butyllithium was added to initiate the reaction. When the conversion rate of 1,3-butadiene monomer reached 100%, the slurry was discharged, wet-coagulated, washed, and dried to obtain the macromolecular branching agent [-BR-]. n Homopolymer (Mn is 560, n≥2).

[0170] (II) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 3;

[0171] (III) Preparation of liquid polybutadiene rubber:

[0172] Other conditions were the same as in Example 3, except that no macromolecular branching agent [-BR-IR-] was added during the preparation of the liquid polybutadiene rubber. n Instead of block copolymers, macromolecular branching agents [-BR-] are added. n The homopolymer, with an addition amount of 29g, was prepared by: purging the 10L stainless steel polymerization reactor with a jacket four times with argon gas; then sequentially adding 4500g of cyclohexane, 500g of 1,3-butadiene, and 106mmol of a multipolar symmetric ether modifier; stirring at 650rpm; cooling to -5℃; then adding 40mmol of n-butyllithium; and finally, when the 1,3-butadiene conversion reached 91.1%, adding 29g of a macromolecular branching agent [-BR-]. n The homopolymer was reacted until the conversion of 1,3-butadiene reached 96.1%. Then, 19g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out. 2.5L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0173] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0174] Comparative Example 4

[0175] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0176] (a) Preparation of macromolecular branching agent: Same as in Example 4.

[0177] (II) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 4.

[0178] (III) Preparation of liquid polybutadiene rubber:

[0179] Other conditions were the same as in Example 4, except that the macromolecular branching agent [-BR-IR-]n block copolymer was added at 50.0% of the conversion rate, not when the conversion rate reached 91.5%. The addition amount was 31g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, argon gas was purged four times. Then, 4800g of cyclohexane, 500g of 1,3-butadiene, and 116mmol of a multipolar symmetric ether regulator were added sequentially. The mixture was stirred at 670rpm and cooled to -7°C. Then, 39mmol of n-butyllithium was added. When the 1,3-butadiene conversion rate reached 50.0%, 31g of the macromolecular branching agent [-BR-IR-] was added. n The reaction continued until the conversion rate reached 96.6%. Then, 21g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out. 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0180] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0181] Comparative Example 5

[0182] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0183] (a) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 5.

[0184] (II) Preparation of liquid polybutadiene rubber:

[0185] Other conditions were the same as in Example 5, except that no macromolecular branching agent [-BR-IR-] was added during the preparation of the liquid polybutadiene rubber. nInstead of a block copolymer, isoprene was added in a quantity of 33g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, argon gas was purged five times, followed by the sequential addition of 4900g cyclohexane and 500g... 1,3-Butadiene and 123 mmol of a multipolar symmetric ether modifier were stirred at 680 rpm and cooled to -8°C. Then, 38 mmol of n-butyllithium was added. When the conversion of 1,3-butadiene reached 91.8%, 33 g of isoprene was added, and the reaction continued until the conversion reached 96.7%. Finally, 24 g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. The mixture was then coagulated, and 3.0 L of demineralized water and 6 mL of sulfuric acid (0.5 mol / L) were added. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0 L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70°C to obtain liquid polybutadiene rubber.

[0186] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0187] Comparative Example 6

[0188] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0189] (a) Preparation of macromolecular branching agents: Same as in Example 6;

[0190] (II) Preparation of ether modifiers with multipolar symmetric structure: Same as in Example 6;

[0191] (III) Preparation of liquid polybutadiene rubber:

[0192] Other conditions were the same as in Example 6, except for the macromolecular branching agent [-BR-IR-] in the preparation of the liquid polybutadiene rubber. n The block copolymer was added at a rate of 42g, specifically: In a jacketed 10L stainless steel polymerization reactor, argon gas was purged five times. Then, 5000g of cyclohexane, 500g of 1,3-butadiene, and 130mmol of a multipolar symmetric ether modifier were added sequentially. The mixture was stirred at 700rpm and cooled to -10℃. Then, 37mmol of n-butyllithium was added. When the conversion reached 92.0%, 42g of the macromolecular branching agent [-BR-IR-] was added. nThe block copolymer was reacted until the conversion rate reached 97.0%. Then, 25g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out. 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was then separated. The oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0193] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0194] Comparative Example 7

[0195] This comparative example provides a liquid polybutadiene rubber, which is prepared by the following steps:

[0196] (a) Preparation of macromolecular branching agents: Same as in Example 6;

[0197] (II) Preparation of ether modifiers with multipolar symmetric structures:

[0198] Other conditions were the same as in Example 6, except that tetrahydro-2-furan propanol was not added during the preparation of the multipolar symmetric structure ether regulator, but propanol was added instead, with an addition amount of 345g. Specifically: first, argon gas was introduced into a 4L stainless steel polymerization reactor with a jacket for purging five times, and then 950g of tetrahydrofuran, 345g of propanol and 155g of hexamethylene diisocyanate were added to the polymerization reactor in sequence. The mixture was stirred at 340rpm and heated to 82°C. Then, 1.8g of triphenylphosphine was added and reacted for 4.6hr. After the reaction was completed, the reaction solution was cooled to room temperature and obtained by rotary evaporation and vacuum drying to prepare the multipolar symmetric structure ether regulator a.

[0199] (III) Preparation of liquid polybutadiene rubber:

[0200] Other conditions were the same as in Example 6, except that a multipolar symmetric structure ether modifier was not added during the preparation of the liquid polybutadiene rubber. Instead, a multipolar symmetric structure ether modifier a was added at a rate of 130 mmol. Specifically, in a 10L stainless steel polymerization reactor with a jacket, argon gas was purged five times. Then, 5000g of cyclohexane, 500g of 1,3-butadiene, and 130mmol of multipolar symmetric structure ether modifier a were added sequentially to the polymerization reactor. The mixture was stirred at 700 rpm and cooled to -10°C. Then, 37mmol of n-butyllithium was added. When the conversion rate of 1,3-butadiene reached 92.0%, 35g of macromolecular branching agent [-BR-IR-] was added. nThe block copolymer was reacted until the conversion of 1,3-butadiene reached 97.0%. Then, 25g of ethanol was added to terminate the polymerization reaction, resulting in a polymerization mixture. Subsequently, coagulation was carried out, and 3.0L of demineralized water and 6mL of sulfuric acid (molar concentration of 0.5mol / L) were added to the mixture. After stirring for 35 minutes, the mixture was allowed to stand and separate into layers. The aqueous phase was separated, and the oil phase was washed three times with 6.0L of demineralized water. The resulting oil phase was then subjected to vacuum distillation and vacuum drying at 70℃ to obtain liquid polybutadiene rubber.

[0201] Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0202] Table 1 Properties of liquid polybutadiene rubber

[0203]

[0204]

[0205] Table 1 shows that, compared with Examples 1-6 and Comparative Examples 1-6, the branching agent prepared in this invention has a significant effect on reducing the dynamic viscosity of high molecular weight liquid polybutadiene rubber. Furthermore, the molecular weight, dosage, and timing of addition of the branching agent affect the dynamic viscosity of high vinyl and high molecular weight liquid polybutadiene rubber. Additionally, Examples 6 and Comparative Example 7 show that multipolar symmetric ether modifiers are significantly superior to low-polarity asymmetric modifiers in increasing the vinyl (1,2-structure) content.

[0206] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A multipolar symmetrical ether modifier having the structure shown in Formula I: In Formula I, R1 is selected from C1-C15 alkylene groups and their derivatives; R2 is selected from C1-C4 straight-chain alkylene groups.

2. The multipolar symmetric ether modifier according to claim 1, wherein, In Formula I, R1 is selected from C1-C9 alkylene groups and their derivatives, C6-C15 aryl groups and their derivatives, and C5-C14 alicyclic groups and their derivatives.

3. A method for preparing the multipolar symmetric ether modifier according to claim 1 or 2, comprising the following steps: The third solvent, tetrahydro-2-furanol, and diisocyanate compounds are mixed, heated to 70-85°C, and a catalyst is added to carry out the reaction. After the reaction is completed, the mixture is cooled, rotary evaporated, and dried to obtain the multipolar symmetric ether modifier.

4. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The mass ratio of the third solvent, reactants, and catalyst is (100-200):100:(0.1-0.4); the reactants are tetrahydro-2-furanol and diisocyanate compounds, and the mass ratio of tetrahydro-2-furanol and diisocyanate compounds is (60-70):(30-40) based on 100 parts of the mass of the reactants.

5. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The stirring speed for the reaction is 300-500 rpm; the reaction time is 3.5-5.0 hours.

6. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The diisocyanate compounds include one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, 4,4-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and lysine diisocyanate.

7. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The tetrahydro-2-furanol includes one or more of tetrahydro-2-furanol, tetrahydro-2-furanethanol, tetrahydro-2-furanpropanol, and tetrahydro-2-furanbutanol.

8. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The catalyst comprises one or more of the following: triphenylphosphine, tributylphosphine, triethylphosphine, triphenylbismuth, dibutyltin diacetate, dibutyltin dilaurate, lead naphthenate, zinc naphthenate, cobalt naphthenate, methyldiethanolamine, and dimethylethanolamine.

9. The method for preparing the multipolar symmetric ether modifier according to claim 3, wherein, The third solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, chlorobenzene, chloromethane, dichloromethane, 1,4-dioxane, and tetrahydrofuran.

10. A method for preparing liquid polybutadiene rubber, comprising the following steps: Step 1: Preparation of macromolecular branching agent: Mix the first solvent, 1,3-butadiene, and structure regulator, heat the mixture, add an initiator to react, and when the conversion rate of 1,3-butadiene reaches 98%-100%, add isoprene to react. When the conversion rate of isoprene reaches 100%, export the slurry, coagulate, wash, and dry to obtain the macromolecular branching agent. Step 2: Preparation of liquid polybutadiene rubber: The second solvent, 1,3-butadiene, and the multipolar symmetric structure ether regulator described in claim 1 or 2 are mixed. After cooling, an initiator is added to carry out the reaction. When the conversion rate of 1,3-butadiene reaches 89%-92%, the macromolecular branching agent obtained in Step 1 is added, and the reaction continues until the conversion rate of 1,3-butadiene reaches 95%-97%. Then, a terminator is added to terminate the polymerization. After coagulation, washing, and drying, the liquid polybutadiene rubber is obtained.

11. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, In step one, based on the sum of the masses of 1,3-butadiene and isoprene being 100 parts, the mass ratio of 1,3-butadiene to isoprene is (68-83):(17-32).

12. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, In step two, the mass ratio of 1,3-butadiene to the macromolecular branching agent is 100:(4-8).

13. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, In step two, the molar ratio of the multipolar symmetric structure ether modifier to the initiator based on Li element is (1.8-3.7):

1.

14. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, The reaction conditions in step one satisfy any one or a combination of two or more of the following (1)-(5): (1) The mass ratio of the first solvent to the monomer raw material is (400-500):100, and the monomer raw material is 1,3-butadiene and isoprene; (2) The molar ratio of the structure modifier to the initiator is (1.5-3.0):1; (3) Add the initiator after heating to 55-60℃; the stirring speed of the reaction is 500-600 rpm; (4) The macromolecular branching agent is a block copolymer of 1,3-butadiene and isoprene, with the structure [-BR-IR-]. n Where: BR is a 1,3-butadiene homopolymer; IR is an isoprene homopolymer, n≥2; (5) The number average molecular weight of the macromolecular branching agent is 700-900.

15. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, The reaction conditions in step two satisfy any one or a combination of two or more of the following (1)-(3): (1) The mass ratio of the second solvent, 1,3-butadiene, macromolecular branching agent and terminating agent is (800-1000):100:(5-7):(2.0-7.0); (2) After cooling to -10 to -1℃, add the initiator; the stirring speed of the reaction is 600-700 rpm; (3) The coagulation operation is as follows: add water and acid to the reaction solution, stir and let stand to separate the water phase and oil phase, and perform vacuum distillation on the oil phase to obtain the liquid polybutadiene rubber.

16. The method for preparing liquid polybutadiene rubber according to claim 10, wherein, The reaction conditions of the preparation method satisfy any one or a combination of two or more of the following (1)-(6): (1) In step one, the structure modifier includes one or more of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, and triethylamine; (2) In step one, the first solvent includes one or more of pentane, hexane, octane and heptane; (3) In step two, the second solvent includes one or more of cyclopentane, cyclohexane, benzene, toluene, xylene, and ethylbenzene; (4) In steps one and two, the initiator is a hydrocarbon monolithium compound RLi, wherein R is selected from C1-C20 saturated aliphatic hydrocarbon groups, C3-C20 alicyclic hydrocarbon groups, and C6-C20 aromatic hydrocarbon groups. (5) In step two, the terminating agent includes one or more of methanol, ethanol, propanol, butanol, isobutanol, and pentanol; (6) Both steps one and two are carried out in an oxygen-free, anhydrous, and inert gas environment.

17. A liquid polybutadiene rubber, which is prepared by the preparation method according to any one of claims 10-16.

18. The liquid polybutadiene rubber according to claim 17, wherein, The liquid polybutadiene rubber has a 1,2-vinyl structure content of 72%-75%; a number average molecular weight ≥12000; and a dynamic viscosity at 45°C ≤2700 poise.

19. The liquid polybutadiene rubber according to claim 18, wherein, The liquid polybutadiene rubber has a number-average molecular weight of 12,000-14,000 and a dynamic viscosity of 2,500-2,700 poise at 45°C.

20. The application of the liquid polybutadiene rubber according to any one of claims 17-19 in the preparation of circuit boards, wherein the steps are as follows: under the action of a crosslinking agent or a curing agent, the liquid polybutadiene rubber is subjected to a curing and crosslinking reaction with resin or glass fiber.

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