Butadiene-isoprene rubber as well as preparation method and application thereof

Abstract

The invention discloses butadiene-isoprene rubber as well as a preparation method and application thereof. The preparation method comprises the following steps: polymerizing a butadiene monomer and an isoprene monomer under a polymerization condition to obtain butadiene-isoprene rubber; wherein in the polymerization process, an initiator and a composite regulator are added, and the composite regulator comprises ethylenediamine tetraacetic acid salt and an asymmetric ether compound. Butadiene and isoprene are used as raw materials to prepare butadiene-isoprene rubber, ethylene diamine tetraacetic acid salt and asymmetric ether compounds are added in the polymerization process to serve as two-component composite regulators to synthesize solution polymerized butadiene-isoprene rubber with high 1, 2-structure content and high 3, 4-structure content, the total content of the 1, 2-structure and the 3, 4-structure in an obtained polymer is stable, and the solution polymerized butadiene-isoprene rubber has the advantages of being low in cost and good in stability. And the regulating capacity of the composite regulator is not easily influenced by the reaction temperature, the reaction is easy to control, various indexes of the product are improved, and the macroscopic comprehensive mechanical property of the polymer is excellent.

Description

Technical Field

[0001] The invention relates to the technical field of solution-polymerized butadiene-isoprene rubber, and in particular to butadiene-isoprene rubber and a preparation method and application thereof. Background Art

[0002] Butadiene-isoprene rubber, referred to as BIR, is obtained by copolymerization of butadiene and isoprene monomers. It not only has excellent low temperature performance, fatigue resistance, and tear resistance, but also has good dynamic mechanical properties, wear resistance, and wet skid resistance. It is an excellent tire tread rubber. Therefore, in recent years, many research and development institutions and rubber companies at home and abroad have increased the research and development of BIR product technology.

[0003] Polarity regulators are often added to anionic polymerization reactions to adjust the polymer microstructure, molecular weight and molecular weight distribution, and the rate of polymerization reaction, especially the adjustment of polymer microstructure (such as the adjustment of the content of polydiene 1,2-structure and 3,4-structure), which makes polarity regulators play a vital role in anionic polymerization.

[0004] CN102558441A discloses a method for copolymerizing butadiene and isoprene in a hydrocarbon solvent at a temperature of 0-130° C. in the presence of organic lithium as an initiator and tetrahydrofurfuryl alcohol ethyl ether as a structure regulator.

[0005] CN1814640A discloses a polymerization method for producing solution polybutadiene-pentadiene rubber, which comprises copolymerizing butadiene and isoprene in a hydrocarbon solvent at a temperature of 0-130°C in the presence of organic lithium as an initiator and ethylene glycol asymmetric ether as a structure regulator.

[0006] CN101007860A discloses a polymerization method for producing solution polybutadiene rubber, comprising the steps of: using organic lithium as an initiator and using 1G / THF, 1G / Et 3 The copolymerization of butadiene and isoprene is carried out in a hydrocarbon solvent in the presence of N or 2G / TMEDA composite structure regulator.

[0007] The regulator disclosed in the prior art is greatly affected by the reaction temperature during the polymerization process, making it difficult to control the content of the 1,2-structure and 3,4-structure of the polydiene as the reaction temperature changes, resulting in a large change in the vinyl content of the polymer, and the problem of premature termination of the polymerization reaction in the later stage of the reaction, thereby affecting the performance of the product. Therefore, it is very important to be able to smoothly control the content of the 1,2-structure and 3,4-structure in the polymer during the polymerization process. Summary of the invention

[0008] The purpose of the present invention is to overcome the problem that the total content of 1,2-structure and 3,4-structure in butadiene-isoprene rubber prepared in the prior art is difficult to control with the change of reaction temperature and the polymerization reaction is easily terminated in advance in the late stage of the reaction, and to provide butadiene-isoprene rubber and its preparation method and application. The present invention adopts a composite regulator to stably regulate and control the 1,2-structure and 3,4-structure, and can initiate and react at a higher reaction temperature. When the reaction is at a high temperature, there is no need to remove the reaction heat, and the rubber obtained thereby has not only good wear resistance, but also high wet skid resistance and low rolling resistance.

[0009] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing butadiene-isoprene rubber, the preparation method comprising: under polymerization conditions, polymerizing butadiene monomer and isoprene monomer to obtain butadiene-isoprene rubber; wherein, during the polymerization process, an initiator and a composite regulator are added, and the composite regulator comprises ethylenediaminetetraacetate and an asymmetric ether compound.

[0010] The second aspect of the present invention provides a butadiene-isoprene rubber prepared by the above-mentioned preparation method, wherein the total content of 1,2-structure and 3,4-structure is 30-80wt%, preferably 50-70wt%, based on the total weight of the butadiene-isoprene rubber.

[0011] The third aspect of the present invention provides use of the aforementioned butadiene-isoprene rubber in a tire.

[0012] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0013] (1) The present invention provides a polymerization method for preparing butadiene-vinyl rubber using butadiene and isoprene as raw materials and adding a composite regulator during the polymerization process. By adding ethylenediaminetetraacetate and an asymmetric ether compound as a two-component composite regulator during the polymerization process, the synthesized solution-polymerized butadiene-vinyl rubber has a medium-high total content of 1,2-structure and 3,4-structure, and the total content of 1,2-structure and 3,4-structure in the polymer is stable, various indicators of the product are improved, and the macroscopic comprehensive mechanical properties of the polymer are excellent.

[0014] (2) The present invention achieves the goal of stably controlling the total content of 1,2-structure and 3,4-structure of the polymer by adding a composite regulator during the polymerization process, and the regulating ability of the composite regulator is not easily affected by the reaction temperature, and the reaction is easy to control. This solves the problem that a symmetrical ether regulator is greatly affected by the polymerization temperature during the polymerization process and is prone to premature termination of the polymerization reaction in the later stage of the polymerization reaction, thereby improving the comprehensive performance of the copolymer.

[0015] (3) The method for preparing high-performance butadiene-vinyl rubber provided by the present invention has the characteristics of simple process, mild polymerization conditions, stable product performance, and good comprehensive performance.

[0016] (4) The high-performance N-butyl rubber obtained by the present invention can be used to make tires, which significantly improves the rolling resistance and wear resistance of the tires, has a smaller rolling resistance, and is beneficial to energy saving of the tires. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The graph is a relationship between the conversion rate of the reaction monomer and the reaction time when the polymerization temperature is 50°C, 60°C and 80°C respectively;

[0018] Figure 2 This is a curve diagram showing the relationship between the total content of 1,2-structure and 3,4-structure in the butadiene-isoprene rubber and the polymerization temperature when EDTANa / BEE is used as a composite regulator;

[0019] Figure 3 It is a curve diagram showing the relationship between the amount of ethylene glycol ethyl tert-butyl ether (BEE) added and the total content of 1,2-structure and 3,4-structure of polydiene when the polymerization temperature is 60°C and the amount of ethylenediaminetetraacetic acid tetrasodium (EDTANa) is fixed;

[0020] Figure 4 This is a curve showing the relationship between the amount of tetrasodium ethylenediaminetetraacetate (EDTANa) added and the total content of 1,2-structure and 3,4-structure of polydiene when the polymerization temperature is 60°C and the amount of ethylene glycol ethyl tert-butyl ether (BEE) is fixed. DETAILED DESCRIPTION

[0021] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0022] The first aspect of the present invention provides a method for preparing butadiene-isoprene rubber, the preparation method comprising: under polymerization conditions, polymerizing butadiene monomer and isoprene monomer to obtain butadiene-isoprene rubber; wherein, during the polymerization process, an initiator and a composite regulator are added, and the composite regulator comprises ethylenediaminetetraacetate and an asymmetric ether compound.

[0023] In the present invention, the polar composite regulator composed of ethylenediaminetetraacetate and asymmetric ether compounds is used to adjust the microstructure of butadiene and isoprene, and to adjust the reactivity ratio of the two so that the two can be randomly copolymerized. After reaching a certain value, the microstructure of the product will enter a "steady state stage", which is very beneficial to the control of the microstructure.

[0024] The invention provides a polymerization method for synthesizing a solution-polymerized butadiene-vinyl rubber with a total content of high 1,2-structure and 3,4-structure. The butadiene-vinyl rubber is prepared by using butadiene and isoprene as raw materials, and ethylenediaminetetraacetate and an asymmetric ether compound are added as a composite regulator during the polymerization process to achieve the purpose of stably controlling the total content of 1,2-structure and 3,4-structure of the polymer, thereby solving the problems in the prior art that a symmetric ether regulator is greatly affected by the polymerization temperature during the polymerization process and is easy to terminate the polymerization reaction in advance in the later stage of the polymerization reaction, thereby improving the comprehensive performance of the copolymer.

[0025] The ethylenediaminetetraacetic acid salts in the present invention include, but are 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.

[0026] In order to increase the total content of 1,2-structure and 3,4-structure of the polymer, in some embodiments of the present invention, the ethylenediaminetetraacetate salt is selected from tetrasodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate or tripotassium ethylenediaminetetraacetate.

[0027] In order to further increase the total content of 1,2-structure and 3,4-structure of the polymer, in some preferred embodiments of the present invention, the ethylenediaminetetraacetate is tetrasodium ethylenediaminetetraacetate.

[0028] In some embodiments of the present invention, the molar ratio of the ethylenediaminetetraacetate to the initiator is 0.1-2:1, 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 in the range consisting of any two values, preferably 0.5-1.5:1.

[0029] In some embodiments of the present invention, the asymmetric ether compound is selected from one or more of ethylene glycol methyl tert-butyl ether, ethylene glycol ethyl tert-butyl ether, ethylene glycol propyl tert-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 sec-butyl ether, ethylene glycol ethyl n-propyl ether and ethylene glycol ethyl isopropyl ether; preferably ethylene glycol ethyl tert-butyl ether.

[0030] In some embodiments of the present invention, the molar ratio of the asymmetric ether compound to the initiator is 0.1-3:1, 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 in the range consisting of any two values, preferably 0.5-2.5:1.

[0031] In some embodiments of the present invention, the initiator is an organic lithium initiator.

[0032] In some embodiments of the present invention, the organic lithium initiator is a hydrocarbon monolithium compound RLi, wherein R is one or more of a saturated aliphatic hydrocarbon group containing 1 to 20 carbon atoms, an alicyclic hydrocarbon group containing 3 to 20 carbon atoms, and an aromatic hydrocarbon group containing 6 to 20 carbon atoms.

[0033] In the present invention, the saturated aliphatic hydrocarbon group is a residue of a saturated aliphatic hydrocarbon from which its hydrogen atoms are removed, and generally has about 1 to 20 carbon atoms. Specific examples of the saturated aliphatic hydrocarbon group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and the like.

[0034] In the present invention, the alicyclic hydrocarbon group is a residue of an alicyclic hydrocarbon from which its hydrogen atoms are removed, and it generally has about 3 to 20 carbon atoms. The alicyclic hydrocarbon group may be a residue of an alicyclic hydrocarbon from which its hydrogen atoms on the aliphatic ring are removed, or may be a residue of an alicyclic hydrocarbon having an aliphatic chain from which its hydrogen atoms on the aliphatic chain are removed. Specific examples of the alicyclic hydrocarbon group include, but are not limited to: cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl; cycloalkylalkyl, such as cyclopentylmethyl, cyclohexylmethyl; and the like.

[0035] In the present invention, the aromatic hydrocarbon group is a residue of an aromatic hydrocarbon from which its hydrogen atoms are removed, and it generally has about 6 to 20 carbon atoms. The aromatic hydrocarbon group may be a residue of an aromatic hydrocarbon from which its hydrogen atoms on the aromatic ring are removed, or may be a residue of an aromatic hydrocarbon with an aliphatic chain from which its hydrogen atoms on the aliphatic chain are removed, or may be a residue of an aromatic hydrocarbon with an aliphatic ring from which its hydrogen atoms on the aliphatic ring are removed. Specific examples of the aromatic hydrocarbon group include, but are not limited to: aryl groups, such as phenyl, tolyl, naphthyl; arylalkyl groups (aralkyl groups), such as benzyl, phenethyl; and the like.

[0036] In some embodiments of the present invention, the hydrocarbon monolithium compound is selected from one or more of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium and dodecyllithium, and is more preferably n-butyllithium or sec-butyllithium.

[0037] In some embodiments of the present invention, based on the total weight of the monomers as 100%, the content of butadiene monomer is 50-90wt%, for example, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, and any value in the range consisting of any two numerical values, preferably 60-80wt%; the content of isoprene monomer is 10-50wt%, for example, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, and any value in the range consisting of any two numerical values, preferably 20-40wt%.

[0038] In some embodiments of the present invention, the polymerization is carried out in a hydrocarbon solvent, wherein the hydrocarbon solvent is selected from one or more of linear alkanes, aromatic hydrocarbons and cycloalkanes.

[0039] In some embodiments of the present invention, the hydrocarbon solvent is selected from one or more of pentane, hexane, octane, heptane, cyclohexane, cyclopentane, benzene, toluene and ethylbenzene, more preferably cyclohexane.

[0040] The present invention does not particularly limit the amount of solvent added, and the amount required for a general polymerization reaction may be used.

[0041] 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.

[0042] The polymerization reaction of the present invention is carried out in an oxygen-free, water-free, preferably in an inert gas environment. The polymerization reaction pressure of the present invention should keep the polymerization system liquid, generally in the range of 0.05-1MPa, usually 0.1-0.3MPa.

[0043] Figure 1The graph is a graph showing the relationship between the monomer conversion rate and the reaction time when the polymerization temperature is 50°C, 60°C and 80°C respectively. Figure 1 It can be seen that when the reaction time reaches 90 minutes, the conversion rate of the reaction monomers reaches more than 95%, indicating that the active chains of the polymers in the polymerization process of the present invention do not suffer from deactivation and premature termination of the polymerization reaction.

[0044] Figure 2 The graph is a relationship between the total content of 1,2-structure and 3,4-structure in butadiene-isoprene rubber and the polymerization temperature when EDTANa / BEE is used as a composite regulator. Figure 2 It can be seen that with the increase of temperature, the total content of 1,2-structure and 3,4-structure is less affected by the polymerization temperature, and the higher 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.

[0045] Figure 3 The graph is a relationship between the amount of ethylene glycol ethyl tert-butyl ether (BEE) added and the total content of 1,2-structure and 3,4-structure of polydiene when the polymerization temperature is 60°C and the amount of ethylenediaminetetraacetic acid tetrasodium (EDTANa) is fixed. Figure 3 It can be seen that under the premise of fixed dosage of tetrasodium ethylenediaminetetraacetate (EDTANa), with the increase of added amount of ethylene glycol ethyl tert-butyl ether (BEE), the total content of 1,2-structure and 3,4-structure gradually increased.

[0046] Figure 4 The graph is a relationship between the amount of ethylenediaminetetraacetic acid tetrasodium (EDTANa) added and the total content of 1,2-structure and 3,4-structure of polydiene when the polymerization temperature is 60°C and the amount of ethylene glycol ethyl tert-butyl ether (BEE) is fixed. Figure 4 It can be seen that under the premise of a fixed amount of ethylene glycol ethyl tert-butyl ether (BEE), with the increase of the amount of ethylenediaminetetraacetic acid tetrasodium (EDTANa) added, the total content of 1,2-structure and 3,4-structure gradually increased.

[0047] In some embodiments of the present invention, the preparation method further comprises: after the polymerization is completed, adding a coupling agent to carry out a coupling reaction.

[0048] The coupling agent of the present invention can be added all at once or in batches.

[0049] In some embodiments of the present invention, the coupling agent is divinylbenzene.

[0050] The coupling agent used in the present invention is divinylbenzene. The use of a multi-active center coupling agent is an effective measure for preparing high-performance butadiene-vinyl rubber. The amount of the coupling agent used depends on the amount of the initiator.

[0051] In some embodiments of the present invention, the molar ratio of the coupling agent to the initiator is 0.1-3:1, 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 in the range consisting of any two values, preferably 0.5-1.5:1.

[0052] The method for preparing high-performance butadiene-pentadiene rubber provided by the present invention has the characteristics of simple process, mild polymerization conditions, stable product performance, good comprehensive performance, etc.

[0053] A second aspect of the present invention provides a butadiene-isoprene rubber obtained by the aforementioned preparation method, wherein, based on the total weight of the butadiene-isoprene rubber, the total content of 1,2-structure and 3,4-structure is 30-80wt%, for example, 30wt%, 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, and any value in the range consisting of any two values, preferably 50-70wt%.

[0054] In the present invention, the butadiene-isoprene rubber is a solution-polymerized butadiene-pentadiene rubber. Due to the steric hindrance effect, the 1,2-structure generated by isoprene is very small and can be ignored. Therefore, the total content of 1,2-structure and 3,4-structure mentioned in the present invention refers to the sum of the content of butadiene 1,2-structure and isoprene 3,4-structure in the solution-polymerized butadiene-pentadiene rubber.

[0055] In the present invention, an INOVA 400 nuclear magnetic resonance spectrometer (1H-NMR) produced by Varian Company of the United States is used to analyze the microstructure of the sample and to determine the butadiene 1,2-structure content and isoprene 3,4-structure content in the solution-polymerized butadiene-pentadiene rubber.

[0056] In some embodiments of the present invention, the number average molecular weight of the butadiene-isoprene rubber is 30,000-300,000 g / mol, for example, 30,000 g / mol, 50,000 g / mol, 100,000 g / mol, 120,000 g / mol, 150,000 g / mol, 200,000 g / mol, 220,000 g / mol, 250,000 g / mol, 280,000 g / mol, 300,000 g / mol, and any value in the range consisting of any two values, preferably 200,000-300,000 g / mol, and the molecular weight distribution index is 1.2-5, for example, 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, and any value in the range consisting of any two values, preferably 1.8-3.

[0057] In some embodiments of the present invention, the butadiene-isoprene rubber is a random polymer.

[0058] The butadiene-isoprene rubber prepared by the preparation method of the invention is a butadiene-isoprene rubber with medium-high 1,2-structure and 3,4-structure contents and is randomly distributed.

[0059] In the butadiene-isoprene rubber, the mass ratio of butadiene structural units to isoprene structural units is 5-9:1-5.

[0060] In some embodiments of the present invention, the glass transition temperature of the butadiene-isoprene rubber is from -91°C to -80°C.

[0061] The random polymer obtained by the present invention is a star-shaped branched butadiene-isoprene rubber, which has the advantages of high branching degree, high coupling efficiency, good randomness, etc., and the star-shaped random butadiene-isoprene rubber has a stable structure, excellent tensile strength, wear resistance and high hardness. In the synthesis process, due to the regulating effect of the polarity regulator, the star-shaped random butadiene-isoprene rubber makes butadiene and isoprene monomers copolymerize randomly, and the structural units in the polymer are evenly distributed, so that the polymer has a relatively low glass transition temperature, and the polymer can still maintain high rubber elasticity at a relatively low temperature, so the star-shaped random butadiene-isoprene rubber has good low temperature resistance. The star-shaped random butadiene-isoprene rubber has high coupling efficiency, a wide molecular weight distribution, and good processability of the butadiene-isoprene rubber, and excellent comprehensive performance makes it widely used in multiple application fields. The tire made of the star-shaped butadiene-isoprene rubber obtained by the present invention significantly improves the rolling resistance and wear resistance of the tire, and the rolling resistance is small, which is conducive to energy saving of the tire.

[0062] The copolymer of the present invention can be obtained in the following manner: an initiator, a monomer, and a composite regulator are added into a polymerization system in a certain order at one time, and after the polymerization of the monomer is completed, a coupling agent is added to carry out a coupling reaction to obtain the copolymer.

[0063] According to a specific embodiment of the present invention, the preparation method of butadiene-isoprene rubber specifically comprises the following steps:

[0064] Step I: preparing a monomer mixture of butadiene-isoprene in an organic solvent, then adding tetrasodium ethylenediaminetetraacetate and ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) composite regulator to the monomer mixture, and then adding an organic lithium initiator, wherein the molar ratio of tetrasodium ethylenediaminetetraacetate (EDTANa) to the initiator is 0.1-2:1, and the molar ratio of ethylene glycol ethyl tert-butyl ether (BEE) to the initiator is 0.1-3:1; carrying out a polymerization reaction under the action of the organic lithium initiator, controlling the polymerization reaction temperature to 50° C.-90° C., the polymerization reaction pressure to 0.1 MPa-0.25 MPa, and the polymerization reaction time to 20 min-80 min, until no free monomer exists in the polymerization reaction, to obtain a polymer, which can be expressed as: PIB-Me, wherein Me is the metal ion of the initiator;

[0065] Step II: After the monomer conversion is complete, add a measured amount of divinylbenzene into the kettle for coupling reaction, control the coupling reaction temperature to 50°C-90°C, the coupling reaction pressure to 0.1MPa-0.25MPa, and the coupling reaction time to 60min-90min to form an active chain: S-(PIB)n-Me;

[0066] Step III: After the reaction is complete, the polymer solution is treated with water, the amount of water used is generally 100-300 times the weight of the initiator, preferably 150-250 times; then an antioxidant is added, the amount of the antioxidant is 0.5%-1% of the weight of the polymer, and then washed, dehydrated and dried to obtain high-performance butadiene-vinyl rubber, the structural formula of which is as follows: S-(PIB)n, the copolymer molecular chain structure characteristics are as follows:

[0067] Before the solvent is evaporated, an antioxidant may be added to the polymer solution, such as one or more of 1076, 1010, 264, TNP, and triisopropanolamine, with the added amount being 0.5-5wt%, preferably 0.5-2wt%.

[0068] The polymer can be separated from the solution by conventional steam stripping and coagulation methods or by a devolatilizing screw extruder.

[0069] The polymerization monomer used in the present invention is a mixture of butadiene and isoprene. In the mixture of butadiene and isoprene, based on the total weight of the monomers being 100%, the butadiene monomer content is 50-90wt%, and the isoprene content is 10-50wt%.

[0070] The solution-polymerized butadiene-pentadiene rubber obtained by the polymerization method of the present invention has a total content of 1,2-structure and 3,4-structure of 30-70%, and the total content of 1,2-structure and 3,4-structure is stable during the polymerization process. The butadiene and isoprene monomer units in the polymer chain of the solution-polymerized butadiene-pentadiene rubber are randomly distributed.

[0071] The number average molecular weight of the solution-polymerized butadiene-pentadiene rubber synthesized by the method of the invention is 30000-300000 g / mol, and the molecular weight distribution index is 1.2-5.

[0072] The third aspect of the present invention provides use of the aforementioned butadiene-isoprene rubber in a tire.

[0073] The tire prepared by using the butadiene-isoprene rubber of the present invention not only has good wear resistance, but also has high wet skid resistance and low rolling resistance.

[0074] In some specific embodiments of the present invention, the coupling efficiency is obtained by subjecting the mixture obtained by coupling to GPC analysis, and the ratio of the peak area of ​​the polymer formed by coupling to the sum of the peak area of ​​the polymer formed by coupling and the peak area of ​​the copolymer remaining after coupling is the coupling efficiency (CE). The higher the coupling efficiency, the better the coupling performance of divinylbenzene, the greater the activity of the macromolecular active species formed, and the more linear branches connected to the central core formed by divinylbenzene through chemical bonds.

[0075] The present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the following description.

[0076] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are conventional products that can be obtained through commercial channels.

[0077] The composition and structure of the modified rubber described in the following examples and comparative examples can be determined by NMR, IR, GPC, elemental analysis, etc., or by preparing and feeding.

[0078] Gas chromatography analysis: The monomer conversion rate during the polymerization process was determined using a GC 14A hydrogen flame gas chromatograph produced by Shimadzu Corporation of Japan.

[0079] Determination of molecular weight: The molecular weight and distribution of the sample were analyzed using a Viscoteck TDA 302 gel permeation chromatograph (GPC) produced by Agilent Technologies, Inc., USA.

[0080] Nuclear magnetic resonance analysis: The microstructure of the sample was analyzed using an INOVA 400 nuclear magnetic resonance spectrometer (1H-NMR) produced by Varian, USA. It is used to determine the butadiene 1,2-structure content and isoprene 3,4-structure content in solution-polymerized butadiene-pentadiene rubber.

[0081] Coupling efficiency determination: The sample was analyzed using a Viscoteck TDA 302 gel permeation chromatography (GPC) produced by Agilent Technologies, Inc., USA.

[0082] Mechanical properties analysis: The mechanical properties of the samples were tested using a 5567 universal material testing machine produced by Instron, USA.

[0083] Glass transition temperature analysis: The glass transition temperature was determined using a synchronous thermal analyzer (TG / DSC, STA449C) from NETZSCH, Germany.

[0084] Mooney viscosity determination: Mooney viscosity was tested using an MV2000 Mooney viscometer from Alpha Corporation of the United States in accordance with GB / T1232.1-2000.

[0085] Example 1

[0086] In a 15 L stainless steel reactor with a jacket, the system was replaced three times by passing argon. 7371g of cyclohexane, 573g of butadiene (accounting for 70% of the total monomer amount) and 246g of isoprene (accounting for 30% of the total monomer amount) were added to the polymerization kettle, and then the composite regulators tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) were added, wherein EDTANa / Li=0.2, BEE / Li=0.2, and then 8.19mmol of n-butyl lithium was added, and the polymerization reaction was carried out under the conditions of a polymerization temperature of 60°C and a polymerization pressure of 0.2MPa. After the polymerization reaction lasted for 60 minutes, the temperature was raised to 80°C after the monomers were completely converted, and 4.09mmol of divinylbenzene was added for coupling reaction, and the reaction was continued for 60min. After the reaction was completed, the reaction mixture was treated with water, 100g of water and 12g of antioxidant 1010 [tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) pentaerythritol ester] were added, and stirred; the obtained rubber solution was subjected to wet coagulation and drying to obtain a solution-polymerized butadiene-pentadiene rubber product. The structure and performance data of the copolymer product are shown in Table 1.

[0087] Example 2

[0088] In a 15 L stainless steel reactor with a jacket, the system was replaced three times by passing argon. 7371g of cyclohexane, 573g of butadiene (accounting for 70% of the total monomer amount) and 246g of isoprene (accounting for 30% of the total monomer amount) were added to the polymerization kettle, and then the composite regulators tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) were added, wherein EDTANa / Li=0.3 and BEE / Li=0.3, and then 8.19mmol of n-butyl lithium was added, and the polymerization reaction was carried out under the conditions of a polymerization temperature of 60°C and a polymerization pressure of 0.2MPa. After the polymerization reaction lasted for 60 minutes, the temperature was raised to 80°C after the monomers were completely converted, and 4.09mmol of divinylbenzene was added for coupling reaction, and the reaction was continued for 60min. After the reaction was completed, the reaction mixture was treated with water, 100g of water and 12g of antioxidant 1010 [tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) pentaerythritol ester] were added, and stirred; the obtained rubber solution was subjected to wet coagulation and drying to obtain a solution-polymerized butadiene-pentadiene rubber product. The structure and performance data of the copolymer product are shown in Table 1.

[0089] Example 3

[0090] In a 15 L stainless steel reactor with a jacket, the system was replaced three times by passing argon. 7371g of cyclohexane, 573g of butadiene (accounting for 70% of the total monomer amount) and 246g of isoprene (accounting for 30% of the total monomer amount) were added to the polymerization kettle, and then the composite regulators tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) were added, wherein EDTANa / Li=0.4 and BEE / Li=0.4, and then 8.19mmol of n-butyl lithium was added, and the polymerization reaction was carried out under the conditions of a polymerization temperature of 60°C and a polymerization pressure of 0.2MPa. After the polymerization reaction lasted for 60 minutes, the temperature was raised to 80°C after the monomers were completely converted, and 4.09mmol of divinylbenzene was added for coupling reaction, and the reaction was continued for 60min. After the reaction was completed, the reaction mixture was treated with water, 100g of water and 12g of antioxidant 1010 [tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) pentaerythritol ester] were added, and stirred; the obtained rubber solution was subjected to wet coagulation and drying to obtain a solution-polymerized butadiene-pentadiene rubber product. The structure and performance data of the copolymer product are shown in Table 1.

[0091] Example 4

[0092] In a 15 L stainless steel reactor with a jacket, the system was replaced three times by passing argon. 7371g of cyclohexane, 573g of butadiene (accounting for 70% of the total monomer amount) and 246g of isoprene (accounting for 30% of the total monomer amount) were added to the polymerization kettle, and then the composite regulators tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) were added, wherein EDTANa / Li=0.5 and BEE / Li=0.5, and then 8.19mmol of n-butyl lithium was added, and the polymerization reaction was carried out under the conditions of a polymerization temperature of 60°C and a polymerization pressure of 0.2MPa. After the polymerization reaction lasted for 60 minutes, the temperature was raised to 80°C after the monomers were completely converted, and 4.09mmol of divinylbenzene was added for coupling reaction, and the reaction was continued for 60min. After the reaction was completed, the reaction mixture was treated with water, 100g of water and 12g of antioxidant 1010 [tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) pentaerythritol ester] were added, and stirred; the obtained rubber solution was subjected to wet coagulation and drying to obtain a solution-polymerized butadiene-pentadiene rubber product. The structure and performance data of the copolymer product are shown in Table 1.

[0093] Example 5

[0094] In a 15 L stainless steel reactor with a jacket, the system was replaced three times by passing argon. 7371g of cyclohexane, 573g of butadiene (accounting for 70% of the total monomer amount) and 246g of isoprene (accounting for 30% of the total monomer amount) were added to the polymerization kettle, and then the composite regulators tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) were added, wherein EDTANa / Li=0.7 and BEE / Li=0.6, and then 8.19mmol of n-butyl lithium was added, and the polymerization reaction was carried out under the conditions of a polymerization temperature of 60°C and a polymerization pressure of 0.2MPa. After the polymerization reaction lasted for 60 minutes, the temperature was raised to 80°C after the monomers were completely converted, and 4.09mmol of divinylbenzene was added for coupling reaction, and the reaction was continued for 60min. After the reaction was completed, the reaction mixture was treated with water, 100g of water and 12g of antioxidant 1010 [tetrakis-(4-hydroxy-3,5-tert-butylphenylpropionic acid) pentaerythritol ester] were added, and stirred; the obtained rubber solution was subjected to wet coagulation and drying to obtain a solution-polymerized butadiene-pentadiene rubber product. The structure and performance data of the copolymer product are shown in Table 1.

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, the use of tetrasodium ethylenediaminetetraacetic acid / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) composite regulator can synthesize high-total content of 1,2-structure and 3,4-structure of butyl rubber. With the increase of the amount of the composite regulator, the total content of 1,2-structure and 3,4-structure of the generated polymer also gradually increases. When the ratio of the amount of the composite regulator tetrasodium ethylenediaminetetraacetic acid (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) to the amount of the initiator is 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 ratio of the amount of tetrasodium ethylenediaminetetraacetic acid (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) to the amount of the initiator is 0.7 and 0.6 respectively, the total content of 1,2-structure and 3,4-structure in the generated polymer reaches 67.39%. The total content of 1,2-structure and 3,4-structure in the polymer chain has more than doubled, indicating that the composite regulator has strong regulating ability, fast reaction speed, high monomer conversion rate, and greatly shortened reaction time. From the test of polymer physical and mechanical properties, the synthesized polymer has stable and qualified indicators and excellent comprehensive mechanical properties.

[0098] Embodiment 6-10

[0099] A solution polybutylene-pentadiene rubber product was prepared according to the method of Example 4, except that the amount of the composite regulator was different, and the other conditions were the same as those of Example 4, as shown in Table 2.

[0100] Table 2

[0101]

[0102]

[0103] It can be seen from Table 2 that with the increase in the amount of the composite regulator, the total content of 1,2-structure and 3,4-structure of the generated polymer gradually increases. When the ratio of the amount of the composite regulator tetrasodium ethylenediaminetetraacetic acid (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) to the amount of the initiator is 2 and 3 respectively, the total content of 1,2-structure and 3,4-structure in the generated polymer chain reaches 85.26%, indicating that when the upper limit of the amount range of the composite regulator described in the present invention is used, a solution-polymerized butadiene-vinyl rubber with a high total content of 1,2-structure and 3,4-structure can be synthesized.

[0104] Examples 11-18

[0105] A solution polymerized butadiene-pentadiene rubber product was prepared according to the method of Example 4, except that the polymerization temperature was different. The other conditions were the same as those of Example 4, as shown in Table 3.

[0106] Table 3

[0107]

[0108] Table 3 (continued)

[0109]

[0110] It can be seen from Table 3 that when the ratio of the amount of the composite regulator tetrasodium ethylenediaminetetraacetate (EDTANa) and ethylene glycol ethyl tert-butyl ether (BEE) to the amount of the initiator is 0.5 and 0.5 respectively, during the polymerization process, the total content of 1,2-structure and 3,4-structure of the generated solution-polymerized butadiene-pentadiene rubber is stable, and the total content of 1,2-structure and 3,4-structure can reach more than 50%. During the reaction process, it is less affected by the polymerization temperature. When the polymerization temperature changes from 50°C to 90°C, the total content of 1,2-structure and 3,4-structure in the final butadiene-pentadiene rubber remains basically unchanged.

[0111] Examples 19-21

[0112] A solution polybutylene-pentadiene rubber product was prepared according to the method of Example 4, except that the butadiene monomer and the pentadiene monomer accounted for the mass percentage of the total monomers respectively, and the other conditions were the same as those of Example 4, as shown in Table 4.

[0113] Table 4

[0114]

[0115]

[0116] It can be seen from Table 4 that under the premise of a certain composite regulator of ethylenediaminetetraacetic acid tetrasodium / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE), the changes in butadiene monomer and isoprene monomer, with the increase of the amount of isoprene monomer, the glass transition temperature of the solution-polymerized butadiene-pentadiene rubber decreases, which is because the glass transition temperature of isoprene rubber is lower than that of butadiene rubber. The total content of 1,2-structure and 3,4-structure in the generated solution-polymerized butadiene-pentadiene rubber does not change much, so changing the ratio of the reaction monomers has little effect on the regulating effect of the reaction regulator.

[0117] Embodiment 22

[0118] A solution polybutylene rubber product was prepared according to the method of Example 4, except that tetrasodium ethylenediaminetetraacetate in the composite regulator was replaced with disodium ethylenediaminetetraacetate, and the other conditions were the same as those of Example 4, as shown in Table 5.

[0119] Embodiment 23

[0120] A solution polybutylene rubber product was prepared according to the method of Example 4, except that ethylene glycol ethyl tert-butyl ether in the composite regulator was replaced with ethylene glycol methyl isopropyl ether, and the other conditions were the same as those of Example 4, as shown in Table 5.

[0121] Embodiment 24

[0122] A solution polybutylene rubber product was prepared according to the method of Example 4, except that the composite regulator was replaced by dipotassium ethylenediaminetetraacetate and ethylene glycol methyl tert-butyl ether, and the other conditions were the same as those of Example 4, as shown in Table 5.

[0123] Embodiment 25

[0124] A solution polybutylene rubber product was prepared according to the method of Example 4, except that the composite regulator was replaced by tripotassium ethylenediaminetetraacetate and ethylene glycol methyl ethyl ether, and the other conditions were the same as those of Example 4, as shown in Table 5.

[0125] Table 5

[0126]

[0127] Comparative Example 1

[0128] A solution polybutylene rubber product was prepared according to the method of Example 4, except that only tetrasodium ethylenediaminetetraacetate (EDTANa) was added as a regulator, wherein EDTANa / Li=1, and the other conditions were the same as those of Example 4, as shown in Table 6.

[0129] Comparative Example 2

[0130] A solution polybutylene rubber product was prepared according to the method of Example 4, except that ethylene glycol ethyl tert-butyl ether (BEE) was used as a regulator, wherein BEE / Li=1, and the other conditions were the same as those of Example 4, as shown in Table 6.

[0131] Comparative Example 3

[0132] A solution polybutadiene rubber product was prepared according to the method of Example 4, except that tetrasodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) was used as a composite regulator, wherein EDTANa / Li=0.5, THF / Li=30, and the remaining conditions were the same as those of Example 4, as shown in Table 6.

[0133] Comparative Example 4

[0134] A solution polybutadiene rubber product was prepared according to the method of Example 4, except that tetrasodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol dimethyl ether (1G) was used as a composite regulator, wherein EDTANa / Li=0.5, 1G / Li=2, and the other conditions were the same as those in Example 4, as shown in Table 6.

[0135] Comparative Examples 5-8

[0136] The polymerization temperature in Comparative Examples 1-4 was respectively replaced from 60° C. to 80° C., and the other conditions remained unchanged, as shown in Table 6.

[0137] Table 6

[0138]

[0139] Table 6 (continued)

[0140]

[0141]

[0142] As can be seen from Table 6, compared with Example 4 and Comparative Example 1 and Comparative Example 2, relative to using tetrasodium ethylenediaminetetraacetate (EDTANa) alone or using ethylene glycol ethyl tert-butyl ether (BEE) alone as a regulator, the present invention uses tetrasodium ethylenediaminetetraacetate / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) as a composite regulator. The regulation ability is stronger. Compared with using tetrasodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) as a composite regulator or using tetrasodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol dimethyl ether (1G) as a composite regulator, the present invention uses tetrasodium ethylenediaminetetraacetate / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) as a composite regulator. The regulation ability is stronger. It can be seen from the above examples and comparative examples that, through the synergistic effect of tetrasodium ethylenediaminetetraacetate and ethylene glycol ethyl tert-butyl ether, the molecular weight of the polymer obtained in the example of the present invention is greater than 200,000 g / mol, the glass transition temperature is lower than -80°C, the total content of 1,2-structure and 3,4-structure is greater than 50wt%, and the coupling efficiency is greater than 60%.

[0143] From the comparison of Examples 4 and 15 and Comparative Examples 1-8, it can be seen that when tetrasodium ethylenediaminetetraacetate / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) is used as a composite regulator, the reaction temperature has little effect on the polymerization reaction, and the total content of polymer 1,2-structure and 3,4-structure is stable and high, while when tetrasodium ethylenediaminetetraacetate (EDTANa) / tetrahydrofuran (THF) and (EDTANa) / ethylene glycol dimethyl ether (1G) are used as composite regulators, as the reaction temperature increases, the regulator is more affected by the reaction temperature, and the total content of 1,2-structure and 3,4-structure is low. This shows that the regulating ability of the regulator used in the comparative example is reduced, and in the later stage of the polymerization reaction, there is a phenomenon of low reaction chain activity and low polymer molecular weight, and the performance of the polymer product is unstable.

[0144] In summary, in the butadiene-vinyl rubber polymer synthesized by using tetrasodium ethylenediaminetetraacetate (EDTANa) / ethylene glycol ethyl tert-butyl ether (EDTANa / BEE) composite regulator, the microstructure on the polymer chain segment is evenly distributed, with a medium-high total content of 1,2-structure and 3,4-structure, and the total content of 1,2-structure and 3,4-structure is stable, the reaction is easy to control, various indicators of the product are improved, and the macroscopic comprehensive mechanical properties of the polymer are excellent; and the regulating ability of the composite regulator of the present invention is not easily affected by the reaction temperature, and the regulating ability is better than the regulator of the comparative example.

[0145] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing butadiene-isoprene rubber, characterized in that: The preparation method comprises: polymerizing butadiene monomer and isoprene monomer under polymerization conditions to obtain butadiene-isoprene rubber; wherein, initiator and composite regulator are added during the polymerization process, and the composite regulator comprises ethylenediaminetetraacetate and asymmetric ether compounds.

2. The preparation method according to claim 1, wherein The EDTA salt is selected from one or more of tetrasodium EDTA, disodium EDTA, dipotassium EDTA and tripotassium EDTA; preferably tetrasodium EDTA.

3. The preparation method according to claim 1 or 2, wherein The molar ratio of the ethylenediaminetetraacetate to the initiator is 0.1-2:

1.

4. The preparation method according to any one of claims 1 to 3, wherein The asymmetric ether compound is selected from one or more of ethylene glycol methyl tert-butyl ether, ethylene glycol ethyl tert-butyl ether, ethylene glycol propyl tert-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 sec-butyl ether, ethylene glycol ethyl n-propyl ether and ethylene glycol ethyl isopropyl ether; preferably ethylene glycol ethyl tert-butyl ether.

5. The preparation method according to any one of claims 1 to 4, wherein: The molar ratio of the asymmetric ether compound to the initiator is 0.1-3:

1.

6. The preparation method according to any one of claims 1 to 5, wherein: The initiator is an organic lithium initiator; Preferably, the organic lithium initiator is a hydrocarbon monolithium compound RLi, wherein R is one or more of a saturated aliphatic hydrocarbon group containing 1 to 20 carbon atoms, an alicyclic hydrocarbon group containing 3 to 20 carbon atoms, and an aromatic hydrocarbon group containing 6 to 20 carbon atoms; More preferably, the hydrocarbon monolithium compound is selected from one or more of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium and dodecyllithium, and further preferably n-butyllithium or sec-butyllithium.

7. The preparation method according to any one of claims 1 to 6, wherein: Based on 100% of the total weight of the monomers, the content of the butadiene monomer is 50-90% by weight, and the content of the isoprene monomer is 10-50% by weight.

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

9. The preparation method according to any one of claims 1 to 8, wherein: 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.

10. The preparation method according to any one of claims 1 to 9, wherein: The preparation method further comprises: after the polymerization is completed, adding a coupling agent to carry out a coupling reaction; Preferably, the coupling agent is divinylbenzene; Preferably, the molar ratio of the coupling agent to the initiator is 0.1-3:

1.

11. Butadiene-isoprene rubber obtained by the preparation method according to any one of claims 1 to 10, 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 30-80 wt %, preferably 50-70 wt %.

12. The butadiene-isoprene rubber according to claim 11, wherein The number average molecular weight of the butadiene-isoprene rubber is 30000-300000 g / mol, and the molecular weight distribution index is 1.2-5; and / or, the butadiene-isoprene rubber is a random polymer; And / or, the butadiene-isoprene rubber has a glass transition temperature of -91°C to -80°C.

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

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