Butadiene-isoprene rubber, method for producing the same, and use thereof

Abstract

The present invention discloses a butadiene-isoprene rubber, a method for producing the same, and its use. The production method includes a step of polymerizing a butadiene monomer and an isoprene monomer under polymerization conditions to obtain a butadiene-isoprene rubber. During the polymerization process, an initiator and a composite regulator are added. The composite regulator includes an ethylenediaminetetraacetate and an asymmetric ether compound. The present invention produces a butadiene-isoprene rubber using butadiene and isoprene as raw materials. During the polymerization process, an ethylenediaminetetraacetate and an asymmetric ether compound are added as a two-component composite regulator to synthesize a solution-polymerized butadiene-isoprene rubber with a medium to high content of 1,2-structure and 3,4-structure. As a result, the total content of 1,2-structure and 3,4-structure in the obtained polymer is stable, the adjustment ability of the composite regulator is less affected by the reaction temperature, the reaction is easy to control, the various indexes of the product are improved, and the macroscopic and comprehensive mechanical properties of the polymer are excellent.

Description

Cross - reference to related applications

[0001] This application claims the benefit of Chinese Patent Application No. 202310682783.5 filed on June 9, 2023, the content of which is incorporated herein by reference.

Technical Field

[0002] The present invention relates to the technical field of solution - polymerized butadiene - isoprene rubber, and specifically relates to butadiene - isoprene rubber, its manufacturing method and use.

Background Art

[0003] Butadiene - isoprene rubber, simply called BIR, is obtained by copolymerizing butadiene monomer and isoprene monomer. It not only has excellent low - temperature properties, fatigue resistance, and tear resistance, but also has excellent dynamic mechanical properties, abrasion resistance, and wet skid resistance, and is excellent as a rubber for tire treads. Therefore, in recent years, many research and development institutions and rubber companies at home and abroad in China have been engaged in the research and development of the technology and process of butadiene - isoprene rubber products.

[0004] Polarity regulators are often added to anionic polymerization reactions to adjust the microstructure, molecular weight and molecular weight distribution of polymers, and the rate of polymerization reactions, especially the microstructure of polymers (for example, the content of polydiene 1,2 - structure and 3,4 - structure, etc.). Thereby, polarity regulators play a very important role in anionic polymerization.

[0005] CN102558441A discloses copolymerizing butadiene and isoprene in a hydrocarbon solvent at a temperature of 0 - 130°C in the presence of organolithium as an initiator and tetrahydrofurfuryl alcohol ethyl ether as a structure regulator.

[0006] CN1814640A discloses a polymerization method for producing solution-polymerized butadiene-isoprene rubber. This method includes copolymerizing butadiene and isoprene in a hydrocarbon solvent at a temperature of 0 to 130°C in the presence of an organic lithium as an initiator and an ethylene glycol asymmetric ether as a structure regulator.

[0007] CN101007860A discloses a polymerization method for producing solution-polymerized butadiene-isoprene rubber. This method includes copolymerizing butadiene and isoprene in a hydrocarbon solvent solution at a temperature of 0 to 130°C in the presence of an organic lithium as an initiator and a 1G / THF, 1G / Et3N or 2G / TMEDA composite structure regulator.

[0008] The regulators disclosed in the prior art are greatly affected by the reaction temperature during the polymerization process, so it becomes difficult to control the contents of the 1,2-structure and 3,4-structure of the polydiene according to the change of the reaction temperature. As a result, the polymer vinyl content changes greatly, and the polymerization reaction tends to end prematurely in the later stage of the reaction, thus affecting the performance of the product. Therefore, it is very important to be able to stably control the contents of the 1,2-structure and 3,4-structure in the polymer during the polymerization process.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The object of the present invention is to provide a butadiene-isoprene rubber, its production method and use to solve the problems existing in the production of butadiene-isoprene rubber by the prior art, in which it becomes difficult to control the total content of the 1,2-structure and 3,4-structure according to the change of the reaction temperature, and the polymerization reaction ends prematurely in the later stage of the reaction. In the present invention, the 1,2-structure and 3,4-structure can be stably adjusted and controlled by a composite regulator, and the reaction can be started and carried out at a high reaction temperature, and there is no need to dissipate the reaction heat even at a high reaction temperature. Thereby, the obtained rubber has high wet skid resistance and low rolling resistance in addition to good abrasion resistance. [Means for Solving the Problem]

[0010] In order to achieve the above object, a first aspect of the present invention includes a step of polymerizing a butadiene monomer and an isoprene monomer under polymerization conditions to obtain a butadiene-isoprene rubber, wherein an initiator and a composite regulator are added during the polymerization process, and the composite regulator includes an ethylenediaminetetraacetate and an asymmetric ether compound, and provides a method for producing a butadiene-isoprene rubber.

[0011] A second aspect of the present invention provides a butadiene-isoprene rubber produced by the above-described production method, wherein based on the total weight of the butadiene-isoprene rubber, the total content of the 1,2-structure and the 3,4-structure is 30 to 80 wt%, preferably 50 to 70 wt%.

[0012] A third aspect of the present invention provides the use of the above-described butadiene-isoprene rubber in a tire. [Advantages of the Invention]

[0013] According to the above technical solution, the beneficial technical effects of the present invention are as follows. (1) The present invention provides a polymerization method for producing a butadiene-isoprene rubber by using butadiene and isoprene as raw materials and adding a composite regulator during the polymerization process. By adding an ethylenediaminetetraacetate and an asymmetric ether compound as a two-component composite regulator during the polymerization process, the synthesized solution-polymerized butadiene-isoprene rubber has a medium to high total content of the 1,2-structure and the 3,4-structure, and the total content of the 1,2-structure and the 3,4-structure in the polymer is stable, the various indexes of the product are improved, and the macroscopic and comprehensive mechanical properties of the polymer are excellent. (2) By adding a composite regulator during the polymerization process, the present invention can stably control the total content of the 1,2-structure and 3,4-structure of the polymer. The regulation ability of the composite regulator is less affected by the reaction temperature, and the reaction is easy to control. Therefore, the symmetric ether-based regulator in the polymerization process is greatly affected by the polymerization temperature, and the polymerization reaction is likely to end prematurely in the later stage of the polymerization reaction. This solves the problem, and improves the comprehensive performance of the copolymer. (3) The method for producing a high-performance butadiene-isoprene rubber according to the present invention has characteristics such as a simple process, mild polymerization conditions, stable product performance, and good comprehensive performance. (4) The tire using the high-performance butadiene-isoprene rubber according to the present invention has significantly improved rolling resistance and abrasion resistance, with a smaller rolling resistance, which is beneficial for energy conservation of the tire.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying out the Invention

[0015] The endpoints and any values within the ranges disclosed in this specification are not limited to exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. In the case of numerical ranges, by combining between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, one or more new numerical ranges can be obtained, and these numerical ranges should be regarded as specifically disclosed in this specification.

[0016] The first aspect of the present invention provides a method for producing butadiene-isoprene rubber, which includes the step of polymerizing a butadiene monomer and an isoprene monomer under polymerization conditions to obtain butadiene-isoprene rubber. During the polymerization process, an initiator and a composite regulator are added, and the composite regulator includes ethylenediaminetetraacetate and an asymmetric ether compound.

[0017] In the present invention, the role of the polar composite regulator composed of ethylenediaminetetraacetate and an asymmetric ether compound is to adjust the microstructure of butadiene and isoprene, adjust the reactivity ratio of the two, and copolymerize them randomly. When a specific value is reached, the microstructure of the product enters the "steady state stage", which is very advantageous for the control of the microstructure.

[0018] The present invention uses butadiene and isoprene as raw materials to produce butadiene-isoprene rubber, and by adding ethylenediaminetetraacetate and an asymmetric ether compound as a composite regulator during the polymerization process, the object of stably controlling the total content of the 1,2-structure and 3,4-structure of the polymer is achieved. The asymmetric ether-based regulator used in the prior art is greatly affected by the polymerization temperature during the polymerization process, and the polymerization reaction is likely to end prematurely in the later stage of the polymerization reaction. The present invention solves this problem and provides a polymerization method for synthesizing solution-polymerized butadiene-isoprene rubber with a medium to high total content of the 1,2-structure and 3,4-structure, which improves the comprehensive performance of the copolymer.

[0019] The ethylenediaminetetraacetate salt in the present invention includes, but is not limited to, one or more of ammonium ethylenediaminetetraacetate, diammonium ethylenediaminetetraacetate, triammonium ethylenediaminetetraacetate, tetraammonium ethylenediaminetetraacetate, sodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, trisodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, potassium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate, tripotassium ethylenediaminetetraacetate, and tetrapotassium ethylenediaminetetraacetate.

[0020] In some embodiments of the present invention, in order to improve the total content of the 1,2-structure and 3,4-structure of the polymer, the ethylenediaminetetraacetate salt is selected from tetrasodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate, or tripotassium ethylenediaminetetraacetate.

[0021] In some preferred embodiments of the present invention, in order to further improve the total content of the 1,2-structure and 3,4-structure of the polymer, the ethylenediaminetetraacetate salt is tetrasodium ethylenediaminetetraacetate.

[0022] In some embodiments of the present invention, the molar ratio of the ethylenediaminetetraacetate salt to the initiator is 0.1 to 2:1, for example, 0.1:1, 0.2:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, and any value within the range consisting of any two numerical values, preferably 0.5 to 1.5:1.

[0023] In some embodiments of the present invention, the asymmetric ether compound is one or more selected from ethylene glycol methyl t-butyl ether, ethylene glycol ethyl t-butyl ether, ethylene glycol propyl t-butyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl n-propyl ether, ethylene glycol methyl isopropyl ether, ethylene glycol methyl isobutyl ether, ethylene glycol methyl s-butyl ether, ethylene glycol ethyl n-propyl ether, and ethylene glycol ethyl isopropyl ether, preferably ethylene glycol ethyl t-butyl ether.

[0024] In some embodiments of the present invention, the molar ratio of the asymmetric ether compound to the initiator is 0.1 to 3:1, for example, 0.1:1, 0.2:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, and any value within the range consisting of any two numerical values, preferably 0.5 to 2.5:1.

[0025] In some embodiments of the present invention, the initiator is an organolithium initiator.

[0026] In some embodiments of the present invention, the organolithium initiator is a hydrocarbyl monolithium compound RLi (where R is one or more of a saturated aliphatic hydrocarbyl having 1 to 20 carbon atoms, an alicyclic hydrocarbyl having 3 to 20 carbon atoms, and an aromatic hydrocarbyl having 6 to 20 carbon atoms).

[0027] In the present invention, the saturated aliphatic hydrocarbyl is a residue obtained by removing a hydrogen atom from a saturated aliphatic hydrocarbon, and the number of carbon atoms is usually about 1 to 20. Specific examples of the saturated aliphatic hydrocarbyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, and the like.

[0028] In the present invention, an alicyclic hydrocarbyl is a residue obtained by removing a hydrogen atom from an alicyclic hydrocarbon, and the number of carbon atoms is usually about 3 to 20. The alicyclic hydrocarbyl may be a residue obtained by removing a hydrogen atom on an aliphatic ring from an alicyclic hydrocarbon, or may be a residue having an aliphatic chain obtained by removing a hydrogen atom on an aliphatic chain from an alicyclic hydrocarbon. Specific examples of the alicyclic hydrocarbyl include, for example, cycloalkyls such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, and cycloalkylalkyls such as cyclopentylmethyl and cyclohexylmethyl.

[0029] In the present invention, an aromatic hydrocarbyl is a residue obtained by removing a hydrogen atom from an aromatic hydrocarbon, and the number of carbon atoms is usually about 6 to 20. The aromatic hydrocarbyl may be a residue obtained by removing a hydrogen atom on an aromatic ring from an aromatic hydrocarbon, may be a residue having an aliphatic chain obtained by removing a hydrogen atom on an aliphatic chain from an aromatic hydrocarbon, or may be a residue having an aliphatic ring obtained by removing a hydrogen atom on an aliphatic ring from an aromatic hydrocarbon. Specific examples of the aromatic hydrocarbyl include aryls such as phenyl, tolyl, and naphthyl, and arylalkyls (aralkyls) such as benzyl and phenethyl.

[0030] In some embodiments of the present invention, the hydrocarbyl monolithium compound is one or more selected from n-butyllithium, s-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium, and dodecyllithium, and more preferably, n-butyllithium or s-butyllithium.

[0031] In some embodiments of the present invention, taking the total weight of the monomers as 100%, the content of the butadiene monomer is 50-90 wt%, for example, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, and any value within the range composed of any two numerical values, preferably 60-80 wt%, and the content of the isoprene monomer is 10-50 wt%, for example, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, and any value within the range composed of any two numerical values, preferably 20-40 wt%.

[0032] In some embodiments of the present invention, the polymerization is carried out in a hydrocarbon solvent, and the hydrocarbon solvent is one or more selected from linear alkanes, aromatic hydrocarbons, and cycloalkanes.

[0033] In some embodiments of the present invention, the hydrocarbon solvent is one or more selected from pentane, hexane, octane, heptane, cyclohexane, cyclopentane, benzene, toluene, and ethylbenzene, and preferably cyclohexane.

[0034] In the present invention, the addition amount of the solvent is not particularly limited, and an amount required for a normal polymerization reaction may be used.

[0035] In some embodiments of the present invention, the polymerization conditions include a polymerization temperature of 20-130°C, preferably 40-100°C, and a polymerization pressure of 0.05-1 MPa, preferably 0.1-0.3 MPa.

[0036] The polymerization reaction of the present invention is carried out without oxygen and water, preferably in an inert gas environment. The polymerization reaction pressure in the present invention needs to keep the polymerization system in a liquid state, and usually 0.05-1 MPa, usually 0.1-0.3 MPa is selected.

[0037] Figure 1 is a graph showing the relationship between the conversion rate of the reaction monomers and the reaction time when the polymerization temperature is 50 °C, 60 °C, and 80 °C. As can be seen from Figure 1, when the reaction time reaches 90 minutes, the conversion rate of the reaction monomers reaches 95% or more, indicating that in the present invention, problems such as inactivation of the polymer active chain and premature termination of the polymerization reaction do not occur during the polymerization process.

[0038] Figure 2 is a graph showing the relationship between the total content of 1,2-structure and 3,4-structure in butadiene-isoprene rubber obtained when sodium ethylenediaminetetraacetate / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) is used as a composite regulator and the polymerization temperature. As can be seen from Figure 2, as the temperature rises, the total content of 1,2-structure and 3,4-structure is less affected by the polymerization temperature, and the greater the content of the composite regulator, the less the total content of 1,2-structure and 3,4-structure is affected by the polymerization temperature.

[0039] Figure 3 is a graph showing the relationship between the addition amount of ethylene glycol ethyl t-butyl ether (BEE) and the total content of 1,2-structure and 3,4-structure of polydiene under the condition that the amount of sodium ethylenediaminetetraacetate (EDTANa) is constant and the polymerization temperature is 60 °C. As can be seen from Figure 3, when the amount of sodium ethylenediaminetetraacetate (EDTANa) used is constant, as the addition amount of ethylene glycol ethyl t-butyl ether (BEE) increases, the total content of 1,2-structure and 3,4-structure gradually increases.

[0040] Figure 4 is a graph showing the relationship between the addition amount of sodium ethylenediaminetetraacetate (EDTANa) and the combined content of 1,2-structure and 3,4-structure of polydiene under the condition that the amount of ethylene glycol ethyl t-butyl ether (BEE) used is constant and the polymerization temperature is 60 °C. As can be seen from Figure 4, when the amount of ethylene glycol ethyl t-butyl ether (BEE) used is constant, as the addition amount of sodium ethylenediaminetetraacetate (EDTANa) increases, the total content of 1,2-structure and 3,4-structure gradually increases.

[0041] In some embodiments of the present invention, after the polymerization is completed, the manufacturing method further includes a step of adding a coupling agent to perform a coupling reaction.

[0042] The coupling agent of the present invention may be added all at once or added in batches.

[0043] In some embodiments of the present invention, the coupling agent is divinylbenzene.

[0044] The coupling agent used in the present invention is divinylbenzene, and the use of a multi-active center coupling agent is an effective means for producing high-performance butadiene-isoprene rubber. The amount of the coupling agent used depends on the amount of the initiator.

[0045] In some embodiments of the present invention, the molar ratio of the coupling agent to the initiator is 0.1 to 3:1, for example, 0.1:1, 0.3:1, 0.6:1, 0.9:1, 1.2:1, 1.5:1, 1.8:1, 2.1:1, 2.4:1, 2.7, 3, and any value within the range consisting of any two numerical values, preferably 0.5 to 1.5:1.

[0046] The manufacturing method of the high-performance butadiene-isoprene rubber according to the present invention is characterized in that the process is simple, the polymerization conditions are mild, the product characteristics are stable, and the comprehensive performance is good.

[0047] The second aspect of the present invention provides a butadiene-isoprene rubber produced by the aforementioned manufacturing method, wherein the total content of the 1,2-structure and the 3,4-structure is 30 to 80 wt%, for example, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, and any value within the range consisting of any two numerical values, preferably 50 to 70 wt%, based on the total weight of the butadiene-isoprene rubber.

[0048] In the present invention, the butadiene-isoprene rubber is a solution-polymerized butadiene-isoprene rubber. Due to the steric hindrance effect, the 1,2-structure formed by isoprene is extremely small and negligible. Therefore, the total content of the 1,2-structure and the 3,4-structure described in the present invention means the sum of the content of the butadiene 1,2-structure and the content of the isoprene 3,4-structure in the solution-polymerized butadiene-isoprene rubber.

[0049] In the present invention, a INOVA 400 nuclear magnetic resonance spectrometer (1H-NMR) manufactured by Varian, USA is used to analyze the microstructure of the sample and measure the content of the butadiene 1,2-structure and the content of the isoprene 3,4-structure in the solution-polymerized butadiene-isoprene rubber.

[0050] In some embodiments of the present invention, the butadiene-isoprene rubber has a number average molecular weight of 30,000 to 300,000 g / mol, such as 30,000, 50,000, 100,000, 120,000, 150,000, 200,000, 220,000, 250,000, 280,000, 300,000, and any value within the range consisting of any two numerical values, preferably 200,000 to 300,000 g / mol, and a molecular weight distribution index of 1.2 to 5, such as 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, and any value within the range consisting of any two numerical values, preferably 1.8 to 3.

[0051] In some embodiments of the present invention, the butadiene-isoprene rubber is a random polymer.

[0052] The butadiene-isoprene rubber produced by the production method of the present invention is a butadiene-isoprene rubber with a medium to high content of 1,2-structure and 3,4-structure and is randomly distributed.

[0053] In the butadiene-isoprene rubber, the mass ratio of the butadiene structural unit to the isoprene structural unit is 5 to 9:1 to 5.

[0054] In some embodiments of the present invention, the glass transition temperature of the butadiene-isoprene rubber is -91°C to -80°C.

[0055] The random polymer obtained by the present invention is a star-branched butadiene-isoprene rubber, which has advantages such as a high degree of branching, high coupling efficiency, and good randomness. This star-shaped random butadiene-isoprene rubber has a stable structure, excellent tensile strength, abrasion resistance, and high hardness. In the synthesis process of this star-shaped random butadiene-isoprene rubber, due to the adjustment effect of the polarity regulator, the butadiene monomer and the isoprene monomer are copolymerized randomly, and the structural units in the polymer are uniformly distributed. As a result, the polymer has a low glass transition temperature and can maintain high rubber elasticity even at low temperatures. Therefore, this star-shaped random butadiene-isoprene rubber has excellent low-temperature resistance. This star-shaped random butadiene-isoprene has a high coupling efficiency and a wide molecular weight distribution, so it has excellent processability and comprehensive performance, and is thus used in many application fields. The tire manufactured from the star-shaped butadiene-isoprene rubber obtained by the present invention can significantly improve the rolling resistance and abrasion resistance of the tire, reduce the rolling resistance, and is beneficial for the energy saving of the tire.

[0056] The copolymer of the present invention is obtained by adding an initiator, a monomer, and a composite regulator to the polymerization system all at once in this order, and after the monomer polymerization is completed, adding a coupling agent to carry out a coupling reaction to obtain the copolymer.

[0057] According to a specific embodiment of the present invention, the method for manufacturing butadiene-isoprene rubber specifically includes the following steps.

[0058] Step I: After preparing a monomer mixture of butadiene and isoprene in an organic solvent, a complex regulator of tetrasodium ethylenediaminetetraacetate and ethylene glycol ethyl t-butyl ether (EDTANa / BEE) is added to the monomer mixture, and then an organolithium initiator is added. Here, the molar ratio of tetrasodium ethylenediaminetetraacetate (EDTANa) to the initiator is 0.1 - 2:1, and the molar ratio of ethylene glycol ethyl t-butyl ether (BEE) to the initiator is 0.1 - 3:1. A polymerization reaction is carried out under the action of the organolithium initiator, controlling the temperature of the polymerization reaction at 50°C - 90°C, the pressure of the polymerization reaction at 0.1 MPa - 0.25 MPa, and the polymerization reaction time at 20 min - 80 min until there is no free monomer left during the polymerization reaction to obtain a polymer represented as PIB-Me (where Me is the metal ion of the initiator).

[0059] Step II: After the conversion of the monomer is completed, the measured divinylbenzene is added to the kettle, and the temperature of the coupling reaction is controlled at 50°C - 90°C, the pressure of the coupling reaction at 0.1 MPa - 0.25 MPa, and the time of the coupling reaction at 60 - 90 min to carry out the coupling reaction to form an active chain: S-(PIB)n-Me.

[0060] Step III: After the reaction is completed, the polymer solution is generally treated with water that is 100 - 300 times the weight of the initiator, preferably 150 - 250 times. Next, an antioxidant is added in an amount of 0.5% - 1% of the weight of the polymer, and then washing, dehydration, and drying are carried out to obtain a high-performance butadiene-isoprene rubber represented by the structural formula: S-(PIB)n. The characteristics of the copolymer molecular chain structure are as follows.

[0061] Before evaporating the solvent, one or more antioxidants such as 1076, 1010, 264, TNP, and triisopropanolamine may be added to the polymer solution in an amount of 0.5 - 5 wt%, preferably 0.5 - 2 wt%.

[0062] The polymer can be separated from the solution by a conventional stripping coagulation method or a devolatilization screw extruder.

[0063] The polymerization monomers used in the present invention are a mixture of butadiene and isoprene. In this mixture of butadiene and isoprene, taking the total weight of the monomers as 100%, the content of butadiene monomer is 50 - 90 wt%, and the content of isoprene is 10 - 50 wt%.

[0064] In the solution-polymerized butadiene-isoprene rubber obtained by the polymerization method of the present invention, the total content of 1,2-structure and 3,4-structure is 30 - 70%, and the total content of 1,2-structure and 3,4-structure is stable during the polymerization process. In this solution-polymerized butadiene-isoprene rubber polymer chain, the units of butadiene and isoprene monomers are randomly distributed.

[0065] The solution-polymerized butadiene-isoprene rubber synthesized by the method of the present invention has a number-average molecular weight of 30,000 - 300,000 g / mol and a molecular weight distribution index of 1.2 - 5.

[0066] The third aspect of the present invention provides the use of the aforementioned butadiene-isoprene rubber in tires.

[0067] The tires manufactured using the butadiene-isoprene rubber of the present invention have high wet skid resistance and low rolling resistance in addition to good abrasion resistance.

[0068] In some specific embodiments of the present invention, the coupling efficiency is determined by GPC analysis of the mixture obtained by coupling, and the ratio of the peak area of the polymer formed by coupling to the sum of the peak areas of the polymer formed by coupling and the remaining copolymer after coupling is the coupling efficiency (CE). The higher the coupling efficiency, the better the coupling property of divinylbenzene, the greater the activity of the formed polymer active species, and the larger the number of linear branches connected to the central core formed by divinylbenzene by chemical bonds.

[0069] Hereinafter, the present invention will be described in more detail by way of examples, but the protection scope of the present invention is not limited to the following description. In addition, in the following examples and comparative examples, conditions not specifically described shall follow conventional conditions or conditions recommended by the manufacturer. When the manufacturer of the reagents and equipment used is not described, commercially available conventional products are used in all cases.

[0070] The composition and structure of the modified rubber described in the following examples and comparative examples can be determined by measurements such as nuclear magnetic resonance, infrared, GPC, elemental analysis, etc., and can also be determined by the preparation input.

[0071] Gas chromatography analysis: Using a GC 14A hydrogen flame gas chromatograph manufactured by Shimadzu Corporation, Japan, the conversion rate of monomers during the polymerization process is measured. Measurement of molecular weight: Using a Viscoteck TDA 302 gel permeation chromatography (GPC) manufactured by Agilent Technologies, USA, the molecular weight and distribution of the sample are analyzed. Nuclear magnetic resonance analysis: Using an INOVA 400 nuclear magnetic resonance spectrometer (1H-NMR) manufactured by Varian, USA, the fine structure of the sample is analyzed. It is used to measure the content of 1,2-structure of butadiene and the content of 3,4-structure of isoprene in solution-polymerized butadiene-isoprene rubber. Measurement of coupling efficiency: Using a Viscoteck TDA 302 gel permeation chromatography (GPC) manufactured by Agilent Technologies, USA, the sample is analyzed and measured. Analysis of mechanical and mechanical properties: Using a 5567 universal material testing machine manufactured by Instron, USA, the mechanical properties of the sample are tested. Analysis of glass transition temperature: Using a synchronous thermal analyzer (TG / DSC, STA449C) of NETZSCH, Germany, the glass transition temperature is measured. Measurement of Mooney viscosity: Using an MV2000 Mooney viscometer of Alpha, USA, the Mooney viscosity is tested in accordance with GB / T 1232.1-2000. Example 1

[0072] The system was replaced three times with argon gas in a 15 L stainless steel reactor with a jacket. 7371 g of cyclohexane, 573 g of butadiene (accounting for 70% of the total amount of monomers), and 246 g of isoprene (accounting for 30% of the total amount of monomers) were added to the polymerization kettle. Next, tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) (where EDTANa / Li = 0.2, BEE / Li = 0.2) were added as a composite regulator. Then, 8.19 mmol of n-butyllithium was added, and the polymerization reaction was carried out for 60 minutes under the conditions of a polymerization temperature of 60 °C and a polymerization pressure of 0.2 MPa. After the monomers were completely converted, the temperature was raised to 80 °C, 4.09 mmol of divinylbenzene was added to carry out a coupling reaction, and the reaction was further carried out for 60 min. After the reaction was completed, the reaction mixture was treated with water, 100 g of water and 12 g of antioxidant 1010 pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added, and it was stirred. The obtained paste was coagulated by the wet method and baked to obtain a solution-polymerized butadiene-isoprene rubber product. The measured structural and characteristic data of the copolymer product are shown in Table 1. Example 2

[0073] The system was purged three times with argon gas in a 15 L stainless steel reactor with a jacket. 7371 g of cyclohexane, 573 g of butadiene (accounting for 70% of the total amount of monomers), and 246 g of isoprene (accounting for 30% of the total amount of monomers) were added to the polymerization kettle. Next, sodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) (where EDTANa / Li = 0.3, BEE / Li = 0.3) were added as a composite regulator. Then, 8.19 mmol of n-butyllithium was added, and the polymerization reaction was carried out for 60 minutes under the conditions of a polymerization temperature of 60 °C and a polymerization pressure of 0.2 MPa. After the monomers were completely converted, the temperature was raised to 80 °C, and 4.09 mmol of divinylbenzene was added to carry out a coupling reaction, and the reaction was further carried out for 60 min. After the reaction was completed, the reaction mixture was treated with water, 100 g of water and 12 g of antioxidant 1010 pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added, and the mixture was stirred. The obtained paste solution was aggregated by the wet method and baked to obtain a solution-polymerized butadiene-isoprene rubber product. The measured structural and characteristic data of the copolymer product are shown in Table 1. Example 3

[0074] In a 15 L stainless steel reactor with a jacket, the system was purged with argon gas three times. 7371 g of cyclohexane, 573 g of butadiene (accounting for 70% of the total amount of monomers), and 246 g of isoprene (accounting for 30% of the total amount of monomers) were added to the polymerization kettle. Next, sodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) (where EDTANa / Li = 0.4, BEE / Li = 0.4) were added as a composite regulator. Then, 8.19 mmol of n-butyllithium was added, and the polymerization reaction was carried out for 60 minutes under the conditions of a polymerization temperature of 60 °C and a polymerization pressure of 0.2 MPa. After the monomers were completely converted, the temperature was raised to 80 °C, and 4.09 mmol of divinylbenzene was added to carry out a coupling reaction, and the reaction was continued for another 60 minutes. After the reaction was completed, the reaction mixture was treated with water, and 100 g of water and 12 g of antioxidant 1010 pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added and stirred. The obtained paste was coagulated by the wet method and baked to obtain a solution-polymerized butadiene-isoprene rubber product. The measured structural and property data of the copolymer product are shown in Table 1. Example 4

[0075] In a 15 L stainless steel reactor with a jacket, the system was purged three times with argon gas. 7371 g of cyclohexane, 573 g of butadiene (accounting for 70% of the total amount of monomers), and 246 g of isoprene (accounting for 30% of the total amount of monomers) were added to the polymerization kettle. Next, sodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) (where EDTANa / Li = 0.5, BEE / Li = 0.5) were added as a composite regulator. Then, 8.19 mmol of n-butyllithium was added, and the polymerization reaction was carried out for 60 minutes under the conditions of a polymerization temperature of 60 °C and a polymerization pressure of 0.2 MPa. After the monomers were completely converted, the temperature was raised to 80 °C, and 4.09 mmol of divinylbenzene was added to carry out a coupling reaction, and the reaction was further carried out for 60 min. After the reaction was completed, the reaction mixture was treated with water, and 100 g of water and 12 g of antioxidant 1010 pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added and stirred. The obtained paste was coagulated by the wet method and baked to obtain a solution-polymerized butadiene-isoprene rubber product. The measured structural and property data of the copolymer product are shown in Table 1. Example 5

[0076] The system was purged three times with argon gas in a 15 L stainless steel reactor with a jacket. 7371 g of cyclohexane, 573 g of butadiene (accounting for 70% of the total amount of monomers), and 246 g of isoprene (accounting for 30% of the total amount of monomers) were added to the polymerization kettle. Next, tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) (where EDTANa / Li = 0.7, BEE / Li = 0.6) were added as a composite regulator. Then, 8.19 mmol of n-butyllithium was added, and the polymerization reaction was carried out for 60 minutes under the conditions of a polymerization temperature of 60 °C and a polymerization pressure of 0.2 MPa. After the monomers were completely converted, the temperature was raised to 80 °C, 4.09 mmol of divinylbenzene was added to carry out a coupling reaction, and the reaction was further carried out for 60 min. After the reaction was completed, the reaction mixture was treated with water, 100 g of water and 12 g of antioxidant 1010 pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added, and the mixture was stirred. The obtained paste was aggregated by the wet method and baked to obtain a solution-polymerized butadiene-isoprene rubber product. The measured structural and characteristic data of the copolymer product are shown in Table 1.

[0077]

Table 1

[0078] As can be seen from Table 1, when using the complex regulator of tetrasodium ethylenediaminetetraacetate / ethyl t-butyl ether of ethylene glycol (EDTANa / BEE), butadiene-isoprene rubber with a medium to high total content of 1,2-structure and 3,4-structure can be synthesized. As the usage amount of the complex regulator increases, the total content of 1,2-structure and 3,4-structure in the generated polymer also gradually increases. When the ratios of the usage amounts of tetrasodium ethylenediaminetetraacetate (EDTANa) and ethyl t-butyl ether of ethylene glycol (BEE) as the complex regulator to the usage amount of the initiator are 0.2 and 0.2 respectively, the total content of 1,2-structure and 3,4-structure in the generated polymer chain is 30.12%. When the ratios of the usage amounts of tetrasodium ethylenediaminetetraacetate (EDTANa) and ethyl t-butyl ether of ethylene glycol (BEE) to the usage amount of the initiator are 0.7 and 0.6 respectively, the total content of 1,2-structure and 3,4-structure in the generated polymer reaches 67.39%, and the total content of 1,2-structure and 3,4-structure in the polymer chain has more than doubled, indicating that the complex regulator has high adjustment ability, fast reaction rate, high monomer conversion rate, and significantly shortened reaction time. Judging from the physical and mechanical properties of the polymer, the various indicators of the synthesized polymer are stable and qualified, and the comprehensive mechanical properties are excellent. Examples 6 to 10

[0079] Except for the different usage amounts of the complex regulator, the remaining conditions were the same as those in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 2.

[0080]

Table 2

[0081] As can be seen from Table 2, as the usage amount of the composite regulator increases, the total content of the 1,2-structure and 3,4-structure of the produced polymer also gradually increases. When the ratios of the usage amounts of tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) as the composite regulator to the usage amount of the initiator are 2 and 3 respectively, the total content of the 1,2-structure and 3,4-structure in the produced polymer chain is 85.26%. Using the upper limit of the usage amount range of the composite regulator described in the present invention indicates that a solution-polymerized butadiene-isoprene rubber with a high total content of 1,2-structure and 3,4-structure can be synthesized. Examples 11 to 18

[0082] Except for the different polymerization temperatures, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 3.

[0083]

Table 3-1

[0084]

Table 3-2

[0085] As can be seen from Table 3, when the ratios of the usage amounts of tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl t-butyl ether (BEE) as the composite regulator to the usage amount of the initiator are 0.5 and 0.5 respectively, during the polymerization process, the total content of the 1,2-structure and 3,4-structure of the produced solution-polymerized butadiene-isoprene rubber is stable, and the total content of the 1,2-structure and 3,4-structure reaches 50% or more. In the reaction process, the influence of the polymerization temperature is small. Even when the polymerization temperature changes from 50°C to 90°C, the total content of the 1,2-structure and 3,4-structure in the finally obtained butadiene-isoprene rubber basically does not change. Examples 19 to 21

[0086] A solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4, with the exception that the mass percentages of butadiene monomer and isoprene monomer in the total amount of monomers were different, and the remaining conditions were the same as those in Example 4. Specifically, it is shown in Table 4.

[0087]

Table 4

[0088] As can be seen from Table 4, although the ethylene diamine tetraacetic acid tetrasodium / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) as the composite regulator was constant, when the butadiene monomer and isoprene monomer changed, as the amount of isoprene monomer increased, the glass transition temperature of the solution-polymerized butadiene-isoprene rubber decreased. This is because the glass transition temperature of isoprene rubber is lower than that of butadiene rubber. Since the total content of 1,2-structure and 3,4-structure in the produced solution-polymerized butadiene-isoprene rubber did not change much, changing the ratio of the reaction monomers had little effect on the adjustment effect of the reaction regulator. Example 22

[0089] A solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4, with the exception that the ethylene diamine tetraacetic acid tetrasodium in the composite regulator was changed to ethylene diamine tetraacetic acid disodium, and the remaining conditions were the same as those in Example 4. Specifically, it is shown in Table 5. Example 23

[0090] A solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4, with the exception that the ethylene glycol ethyl t-butyl ether in the composite regulator was changed to ethylene glycol methyl isopropyl ether, and the remaining conditions were the same as those in Example 4. Specifically, it is shown in Table 5. Example 24

[0091] Except for changing the composite regulator to dipotassium ethylenediaminetetraacetate and ethylene glycol methyl t-butyl ether, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 5. Example 25

[0092] Except for changing the composite regulator to tripotassium ethylenediaminetetraacetate and ethylene glycol methyl ethyl ether, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 5.

[0093] [Table 5] Comparative Example 1

[0094] Except for adding only tetrasodium ethylenediaminetetraacetate (EDTANa) (EDTANa / Li = 1) as a regulator, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 6. Comparative Example 2

[0095] Except for using ethylene glycol ethyl t-butyl ether (BEE) (BEE / Li = 1) as a regulator, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 6. Comparative Example 3

[0096] Except for using tetrasodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) (EDTANa / Li = 0.5, THF / Li = 30) as a composite regulator, the remaining conditions were the same as in Example 4, and a solution-polymerized butadiene-isoprene rubber product was produced according to the method of Example 4. Specifically, it is shown in Table 6. Comparative Example 4

[0097] A solution polymerization butadiene-isoprene rubber product was produced according to the method of Example 4, with the remaining conditions being the same as those in Example 4, except that tetrasodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol dimethyl ether (1G) (EDTANa / Li = 0.5, 1G / Li = 2) was used as a composite regulator. Specifically, it is shown in Table 6. Comparative Examples 5 to 8 Except for changing the polymerization temperature of each of Comparative Examples 1 to 4 from 60 °C to 80 °C, the remaining conditions were kept constant. Specifically, it is shown in Table 6.

[0098]

Table 6-1

[0099]

Table 6-2

[0100] As can be seen from Table 6, when comparing Example 4 with Comparative Example 1 and Comparative Example 2, the present invention has a stronger adjustment ability by using tetrasodium ethylenediaminetetraacetate (EDTANa) alone or ethylene glycol ethyl t-butyl ether (BEE) alone as an adjusting agent, compared with the case of using the combination of tetrasodium ethylenediaminetetraacetate / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) as a composite adjusting agent. From the comparison between Example 4 and Comparative Example 3 and Comparative Example 4, the present invention has a stronger adjustment ability by using tetrasodium ethylenediaminetetraacetate / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) as a composite adjusting agent, compared with the case of using tetrasodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) or tetrasodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol dimethyl ether (1G) as a composite adjusting agent. From the above Examples and Comparative Examples, due to the synergistic effect of tetrasodium ethylenediaminetetraacetate and ethylene glycol ethyl t-butyl ether, the polymer obtained in the Examples of the present invention has a molecular weight exceeding 200,000 g / mol, a glass transition temperature of less than -80 °C, a total content of 1,2-structure and 3,4-structure exceeding 50 wt%, and a coupling efficiency exceeding 60%.

[0101] From the comparison between Example 4 and 15 and Comparative Examples 1 to 8, when sodium ethylenediaminetetraacetate / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) is used as the composite regulator, the reaction temperature has little effect on the polymerization reaction, and the total content of the 1,2-structure and 3,4-structure of the polymer is stable and shows a high value. On the other hand, when sodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) or (EDTANa) / ethylene glycol dimethyl ether (1G) is used as the composite regulator, the higher the reaction temperature, the greater the influence of the reaction temperature, and the total content of the 1,2-structure and 3,4-structure decreases. This indicates that the regulation ability of the regulator used in the comparative example decreases, the activity of the reaction chain is low in the later stage of the polymerization reaction, the molecular weight of the polymer is low, and the performance of the polymer product is unstable.

[0102] As described above, in the butadiene-isoprene rubber polymer synthesized using the sodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol ethyl t-butyl ether (EDTANa / BEE) composite regulator, the fine structure of the polymer chain segments is uniformly distributed, and the total content of the 1,2-structure and 3,4-structure is medium to high and stable. The reaction is easy to control, the various indexes of the product are improved, and the macroscopic and comprehensive mechanical properties of the polymer are excellent. In addition, the composite regulator of the present invention is less affected by the reaction temperature in terms of regulation ability and has better regulation ability than the regulator of the comparative example.

[0103] As mentioned above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a plurality of simple modifications can be made to the technical solution of the present invention, including combining each technical feature in any other appropriate way. These simple modifications and combinations should also be regarded as the disclosure content of the present invention and all belong to the protection scope of the present invention.

Claims

1. A method for producing butadiene-isoprene rubber, comprising the step of polymerizing a butadiene monomer and an isoprene monomer under polymerization conditions to obtain a butadiene-isoprene rubber, wherein an initiator and a composite regulator are added during the polymerization process, and the composite regulator comprises an ethylenediaminetetraacetate and an asymmetric ether compound.

2. The ethylenediaminetetraacetate is one or more selected from sodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate, and tripotassium ethylenediaminetetraacetate, preferably sodium ethylenediaminetetraacetate. The production method according to claim 1.

3. The molar ratio of the ethylenediaminetetraacetate to the initiator is 0.1 to 2:

1. The production method according to claim 1 or 2.

4. The asymmetric ether compound is one or more selected from ethylene glycol methyl t-butyl ether, ethylene glycol ethyl t-butyl ether, ethylene glycol propyl t-butyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl n-propyl ether, ethylene glycol methyl isopropyl ether, ethylene glycol methyl isobutyl ether, ethylene glycol methyl s-butyl ether, ethylene glycol ethyl n-propyl ether, and ethylene glycol ethyl isopropyl ether, preferably ethylene glycol ethyl t-butyl ether. The production method according to any one of claims 1 to 3.

5. The molar ratio of the asymmetric ether compound to the initiator is 0.1 to 3:

1. The production method according to any one of claims 1 to 4.

6. The initiator is an organolithium initiator. Preferably, the organolithium initiator is a hydrocarbyl monolithium compound RLi (wherein R is one or more of a saturated aliphatic hydrocarbyl having 1 to 20 carbon atoms, an alicyclic hydrocarbyl having 3 to 20 carbon atoms, and an aromatic hydrocarbyl having 6 to 20 carbon atoms). More preferably, the hydrocarbyl monolithium compound is one or more selected from n-butyllithium, s-butyllithium, methylbutyllithium, phenylbutyllithium, naphthyllithium, cyclohexyllithium, and dodecyllithium, and even more preferably, n-butyllithium or s-butyllithium. The production method according to any one of claims 1 to 5.

7. Based on the total weight of the monomers being 100%, the content of the butadiene monomer is 50 to 90 wt%, and the content of the isoprene monomer is 10 to 50 wt%. The production method according to any one of claims 1 to 6.

8. The polymerization is carried out in a hydrocarbon solvent, and the hydrocarbon solvent is one or more selected from linear alkanes, aromatic hydrocarbons, and cycloalkanes. Preferably, the hydrocarbon solvent is one or more selected from pentane, hexane, octane, heptane, cyclohexane, cyclopentane, benzene, toluene, and ethylbenzene, and more preferably cyclohexane. The production method according to any one of claims 1 to 7.

9. The polymerization conditions include a polymerization temperature of 20 to 130°C, preferably 40 to 100°C, and a polymerization pressure of 0.05 to 1 MPa, preferably 0.1 to 0.3 MPa. The production method according to any one of claims 1 to 8.

10. The production method further includes a step of adding a coupling agent to perform a coupling reaction after the polymerization is completed. Preferably, the coupling agent is divinylbenzene. Preferably, the molar ratio of the coupling agent to the initiator is 0.1 to 3:

1. The production method according to any one of claims 1 to 9.

11. Based on the total weight of the butadiene-isoprene rubber, the total content of the 1,2-structure and the 3,4-structure is 30 to 80 wt%, preferably 50 to 70 wt%. The butadiene-isoprene rubber produced by the production method according to any one of claims 1 to 10.

12. The butadiene-isoprene rubber has a number average molecular weight of 30,000 to 300,000 g / mol and a molecular weight distribution index of 1.2 to 5. And / or, the butadiene-isoprene rubber is a random polymer. And / or, the glass transition temperature of the butadiene-isoprene rubber is -91°C to -80°C, the butadiene-isoprene rubber according to claim 11.

13. Use of the butadiene-isoprene rubber according to claim 11 or 12 in a tire.

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