Butadiene rubber alloy, method for producing the same, and use thereof

Abstract

The application relates to a cis-butadiene rubber alloy and a preparation method and application thereof, wherein the preparation method of the cis-butadiene rubber alloy comprises the following steps: coupling rare earth cis-butadiene rubber and nickel-based cis-butadiene rubber to obtain composite cis-butadiene rubber, the mass of the rare earth cis-butadiene rubber is greater than that of the nickel-based cis-butadiene rubber, and the Mooney viscosity of the composite cis-butadiene rubber is 35MU-55MU, and the branching factor is 3.0-7.1; preparing syndiotactic 1,2-polybutadiene in the composite cis-butadiene rubber glue in situ to obtain a polymerization glue; and the polymerization glue is condensed and dried to obtain the cis-butadiene rubber alloy. The cis-butadiene rubber alloy prepared by the preparation method has excellent wet skid resistance, tensile strength and tear strength, and has good processing performance and cold flow resistance, so that the requirements of tires on high strength and high modulus can be better met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of synthetic rubber, in particular to a butadiene rubber alloy and a preparation method and application thereof. BACKGROUND

[0002] At present, rare earth butadiene rubber or nickel butadiene rubber is mostly used in the prior art as a rubber species for preparing tires. However, the existing rare earth butadiene rubber or nickel butadiene rubber needs to be reinforced when applied to the tire side, so as to meet the requirements of high strength and high modulus of the tire side. In the traditional process, the modulus of the tire side is mostly improved by adding inorganic fillers or increasing the crosslinking degree, but such methods will cause high internal friction, high heat generation, poor aging performance and other adverse results.

[0003] Although the rubber alloy prepared by introducing syndiotactic 1,2-polybutadiene into the rare earth butadiene rubber or nickel butadiene rubber in situ in the market can improve the reinforcing effect and reduce the internal friction of the tire, the rubber alloy prepared by this method still has the problems of poor processing performance, poor wet skid resistance, low tensile strength and tear strength, so as to meet the requirements of high strength and high modulus of the tire. SUMMARY

[0004] Therefore, it is necessary to provide a butadiene rubber alloy and a preparation method and application thereof in view of the above problems. The butadiene rubber alloy prepared by the preparation method has excellent wet skid resistance, tensile strength and tear strength, and good processing performance and cold flow resistance, so as to better meet the requirements of high strength and high modulus of the tire.

[0005] A preparation method of a butadiene rubber alloy, comprising the following steps:

[0006] The rare earth butadiene rubber and the nickel butadiene rubber are coupled to obtain a composite butadiene rubber, wherein the mass of the rare earth butadiene rubber is greater than the mass of the nickel butadiene rubber, and the Mooney viscosity of the composite butadiene rubber is 35MU-55MU, and the branching factor is 3.0-7.1;

[0007] Syndiotactic 1,2-polybutadiene is prepared in the composite butadiene rubber glue solution in situ to obtain a polymerization glue solution;

[0008] The polymerization glue solution is coagulated and dried to obtain the butadiene rubber alloy.

[0009] In one of the embodiments, the step of coupling the rare earth butadiene rubber and the nickel butadiene rubber to obtain a composite butadiene rubber also meets at least one of the following conditions:

[0010] (1) the rare earth butadiene rubber has a Mooney viscosity of 30 MU-50 MU, a branching factor of 1.5-2.0, a number average molecular weight of 8.0 kg / mol-10.0 kg / mol, a weight average molecular weight of 16.0 kg / mol-30.0 kg / mol, a molecular weight distribution of 2.0-3.0, and a mass fraction of cis-1,4-structure in the rare earth butadiene rubber greater than or equal to 98 %;

[0011] (2) the nickel butadiene rubber has a Mooney viscosity of 30 MU-50 MU, a branching factor of 15-20, a number average molecular weight of 7.0 kg / mol-9.5 kg / mol, a weight average molecular weight of 21.5 kg / mol-34.2 kg / mol, a molecular weight distribution of 3.2-3.6, and a mass fraction of cis-1,4-structure in the nickel butadiene rubber greater than 96 %;

[0012] (3) the composite butadiene rubber has a number average molecular weight of 7.8 kg / mol-9.6 kg / mol, a weight average molecular weight of 22.0 kg / mol-31.7 kg / mol, a molecular weight distribution of 2.8-3.3, and a mass fraction of cis-1,4-structure in the composite butadiene rubber greater than or equal to 96 %;

[0013] (4) the rare earth butadiene rubber is selected from neodymium butadiene rubber;

[0014] (5) the rare earth butadiene rubber, the nickel butadiene rubber, a coupling agent, and an organic solvent are mixed and coupled to obtain the composite butadiene rubber.

[0015] In one embodiment, the step of mixing and coupling the rare earth butadiene rubber, the nickel butadiene rubber, a coupling agent, and an organic solvent also satisfies at least one of the following conditions:

[0016] (1) the mass ratio of the rare earth butadiene rubber to the nickel butadiene rubber is 4:1-19:1;

[0017] (2) the mass ratio of the rare earth butadiene rubber to the coupling agent is 125:1-1000:1;

[0018] (3) the coupling agent is selected from at least one of divinyl dimethyl silane, triethoxysilane, 3-chloropropyl triethoxysilane, 4-chloropropyl methyl dimethoxysilane, 3-chloropropyl methyl diethoxysilane, bis-[γ-(triethoxysil)propyl]tetrasulfide, n-propyl trichlorosilane, silicon tetrachloride, tin tetrachloride, dichlorodisulfide.

[0019] In one of the embodiments, in the step of preparing syndiotactic 1,2-polybutadiene in-situ in the compounded cis-butadiene rubber solution, the compounded cis-butadiene rubber solution and the butadiene monomer solution are mixed and subjected to in-situ polymerization reaction in the presence of an iron-based catalyst or a cobalt-based catalyst.

[0020] In one of the embodiments, in the step of mixing and subjecting to in-situ polymerization reaction of the compounded cis-butadiene rubber solution and the butadiene monomer solution, at least one of the following conditions is met:

[0021] (1) the molar ratio of the compounded cis-butadiene rubber in the compounded cis-butadiene rubber solution to the butadiene monomer in the butadiene monomer solution is 3:2-19:1;

[0022] (2) the polymerization temperature is 30-50℃, and the polymerization time is 30-60min.

[0023] In one of the embodiments, when the compounded cis-butadiene rubber solution and the butadiene monomer solution are mixed and subjected to in-situ polymerization reaction in the presence of an iron-based catalyst, at least one of the following conditions is met:

[0024] (1) the molar ratio of the butadiene monomer in the butadiene monomer solution to the iron element in the iron-based catalyst is 5000:1-40000:1;

[0025] (2) the iron-based catalyst comprises an iron compound, a phosphine-containing compound and an alkyl aluminum, and the molar ratio of the iron compound, the phosphine-containing compound and the alkyl aluminum is 1:3:10-1:20:50.

[0026] In one of the embodiments, when the compounded cis-butadiene rubber solution and the butadiene monomer solution are mixed and subjected to in-situ polymerization reaction in the presence of a cobalt-based catalyst, at least one of the following conditions is met:

[0027] (1) the molar ratio of the butadiene monomer in the butadiene monomer solution to the cobalt element in the cobalt-based catalyst is 5000:1-40000:1;

[0028] (2) the cobalt-based catalyst comprises a soluble cobalt compound, an alkyl aluminum and carbon disulfide, and the molar ratio of the soluble cobalt compound, the alkyl aluminum and the carbon disulfide is 1:10:2-1:100:20.

[0029] A cis-butadiene rubber alloy prepared by the method described above, the cis-butadiene rubber alloy comprising a compounded cis-butadiene rubber and syndiotactic 1,2-polybutadiene dispersed in the compounded cis-butadiene rubber.

[0030] In one of the embodiments, the butadiene rubber alloy has a Mooney viscosity of 39MU-85MU, a branching factor of 3.5-8.5, a melting point of 196℃-203℃, a mass fraction of 3.5%-30% of the meso 1,2-polybutadiene in the butadiene rubber alloy, and a mass fraction of 69%-95.5% of the cis 1,4-structure in the butadiene rubber alloy.

[0031] Use of the butadiene rubber alloy as described above in a tire.

[0032] In the preparation method of the butadiene rubber alloy, the composite butadiene rubber coupled by the rare earth butadiene rubber and the nickel-based butadiene rubber is used as the base rubber, and the use proportion of the rare earth butadiene rubber and the nickel-based butadiene rubber is limited, so that the composite butadiene rubber can have excellent properties of the rare earth butadiene rubber and the nickel-based butadiene rubber, that is, excellent processing performance and mechanical properties. Meanwhile, by controlling the Mooney viscosity and the branching factor of the composite butadiene rubber, the problem of sudden increase of the Mooney viscosity caused by the introduction of the meso 1,2-polybutadiene can be effectively avoided, so that the prepared rubber alloy has better processing performance, cold flow resistance, better wet skid resistance, tensile strength and tear strength, and the uniform dispersion of the meso 1,2-polybutadiene in the composite butadiene rubber is more favorable, the interaction between the meso 1,2-polybutadiene and the composite butadiene rubber is further enhanced, and the reinforcing effect can be better improved, so that the tensile strength, tear strength and modulus of the butadiene rubber alloy and the resistance to bending crack propagation are further improved.

[0033] Therefore, the butadiene rubber alloy prepared by the preparation method has excellent wet skid resistance, tensile strength and tear strength, and good processing performance and cold flow resistance, so that the requirements of the tire for high strength and high modulus can be better met. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 The infrared spectrum of the butadiene rubber alloy prepared in Example 1 in the present application;

[0036] Figure 2 The differential scanning calorimetry curve of the butadiene rubber alloy prepared in Example 1 in the present application, wherein Tc represents the crystallization temperature and Tm represents the melting point temperature. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present application, the present application will be described in more detail below. However, it should be understood that the present application can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the disclosure of the present application more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the present application. As used herein, the term "and / or", which can optionally be used in various places in this document, includes any suitable combination of one or more of the associated listed items, including combinations that contain only a single one of the associated listed items.

[0039] The present application provides a preparation method of butadiene rubber alloy, comprising the following steps:

[0040] S1, coupling rare earth butadiene rubber and nickel butadiene rubber to obtain composite butadiene rubber, wherein the mass of the rare earth butadiene rubber is greater than the mass of the nickel butadiene rubber, and the Mooney viscosity of the composite butadiene rubber is 35MU-55MU, and the branching factor is 3.0-7.1;

[0041] S2, preparing syndiotactic 1,2-polybutadiene in situ in the composite butadiene rubber glue solution to obtain a polymerization glue solution;

[0042] S3, coagulating and drying the polymerization glue solution to obtain butadiene rubber alloy.

[0043] The rare earth butadiene rubber has excellent wear resistance, wet skid resistance, low heat accumulation, low rolling resistance and high bending fatigue resistance, but the pure rare earth butadiene rubber has poor cold flow resistance and poor processing performance, and the tensile strength, tear strength and modulus of its sulfide and the resistance to bending crack propagation are relatively low. Therefore, in the present application, the rare earth butadiene rubber is used as the main component, and the nickel butadiene rubber is used as the auxiliary component for coupling. The prepared composite butadiene rubber not only has the excellent performance of the rare earth butadiene rubber, but also has the easy processing performance, extrusion performance and good cold flow resistance of the nickel butadiene rubber, that is, it has both mechanical properties and processing performance. The problem of sudden increase in Mooney viscosity caused by the introduction of syndiotactic 1,2-polybutadiene (sPB) can be effectively avoided. The prepared rubber alloy has excellent wet skid resistance, tensile strength and tear strength, and also has good processing performance and cold flow resistance.

[0044] Further, the control of the Mooney viscosity of the composite cis-butadiene rubber to be 35MU-55MU and the branching factor to be 3.0-7.1 can not only further improve the processing performance and mechanical properties of the rubber alloy, but also be more conducive to the uniform dispersion of the syndiotactic 1,2-polybutadiene in the composite cis-butadiene rubber, further enhance the interaction between the syndiotactic 1,2-polybutadiene and the composite cis-butadiene rubber, and better improve the reinforcing effect, thereby further improving the tensile strength, tear strength and modulus of the cis-butadiene rubber alloy and the resistance to bending crack propagation.

[0045] Therefore, the cis-butadiene rubber alloy prepared by the preparation method has excellent wet skid resistance, tensile strength and tear strength, good processing performance and cold flow resistance, thereby improving the bending fatigue resistance, flex resistance, crack resistance and weather resistance of the vulcanizate, and further better meeting the requirements of the tire on high strength and high modulus.

[0046] In addition, the viscosity of the composite cis-butadiene rubber solution in the present application is relatively low, and the in-situ introduction of the syndiotactic 1,2-polybutadiene is more conducive to the dispersion of the syndiotactic 1,2-polybutadiene in the composite cis-butadiene rubber, thereby further improving the reinforcing effect and better avoiding the problems of high internal friction, high heat generation and poor aging performance caused by the traditional process (increasing the modulus of the tire side by adding inorganic fillers or increasing the crosslinking degree).

[0047] It should be noted that the rare earth cis-butadiene rubber in the present application refers to linear rare earth cis-butadiene rubber unless otherwise specified. Meanwhile, in the present application, the coupling of the rare earth cis-butadiene rubber and the nickel-based cis-butadiene rubber to obtain the composite cis-butadiene rubber can improve the compatibility between the rare earth cis-butadiene rubber and the nickel-based cis-butadiene rubber, better control the viscosity of the composite cis-butadiene rubber, thereby endowing the cis-butadiene rubber alloy with easy processing characteristics; meanwhile, the molecular chains of the rare earth cis-butadiene rubber and the nickel-based cis-butadiene rubber are connected in a covalent bond manner, and an integral body with a branched structure is formed between the molecular chains, thereby endowing the composite cis-butadiene rubber with excellent wet skid resistance, and improving the tensile strength, elongation at break and modulus of the rubber compound; in addition, the branched structure is more conducive to the interface contact between the rubber phase and the plastic phase sPB, so that the sPB is more uniformly distributed, thereby improving the processing performance of the rubber compound, the mechanical properties and the heat build-up resistance.

[0048] In step S1, the rare earth cis-butadiene rubber, the nickel-based cis-butadiene rubber, the coupling agent and the organic solvent are mixed and coupled to obtain the composite cis-butadiene rubber.

[0049] Specifically, the rare earth butadiene rubber and the nickel butadiene rubber are dissolved in an organic solvent, then a coupling agent is added, followed by filtration to remove impurities, to obtain the composite butadiene rubber. In this process, the rare earth butadiene rubber and the nickel butadiene rubber are connected together by covalent bonds through the addition of the coupling agent, so that the linear rare earth butadiene rubber has a long-chain branched structure.

[0050] Optionally, the mass ratio of the rare earth butadiene rubber to the nickel butadiene rubber is 4:1-19:1. In this way, the synergistic effect of the excellent properties of the rare earth butadiene rubber and the nickel butadiene rubber can be better exerted, and the relationship between the mechanical properties and the processing properties of the composite butadiene rubber can be better balanced, further improving the mechanical properties and the processing properties of the composite butadiene rubber.

[0051] Optionally, the mass ratio of the rare earth butadiene rubber to the coupling agent is 125:1-1000:1. In this way, the coupling effect of the rare earth butadiene rubber and the nickel butadiene rubber can be better improved, the dispersion effect of the syndiotactic 1,2-polybutadiene in the composite butadiene rubber can be further improved, and the reinforcing effect can be improved, and at the same time, the compatibility between the butadiene rubber alloy and other fillers or rubbers during vulcanization can be improved, and the modulus and the mechanical strength of the butadiene rubber alloy when applied to tires can be better met.

[0052] Optionally, the coupling agent is selected from at least one of divinyl dimethyl silane, triethoxysilane, 3-chloropropyl triethoxysilane, 4-chloropropyl methyl dimethoxysilane, 3-chloropropyl methyl diethoxysilane, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, n-propyltrichlorosilane, silicon tetrachloride, tin tetrachloride, and dichlorodisulfide.

[0053] In an embodiment, the organic solvent is selected from at least one of n-hexane, cyclohexane, cyclopentane, and n-heptane.

[0054] Optionally, the rare earth butadiene rubber has a Mooney viscosity of 30MU-50MU, a branching factor of 1.5-2.0, a number average molecular weight (Mn) of 8.0 kg / mol-10.0 kg / mol, a weight average molecular weight (Mw) of 16.0 kg / mol-30.0 kg / mol, a molecular weight distribution (PDI) of 2.0-3.0, and a mass fraction of cis-1,4-structure in the rare earth butadiene rubber greater than or equal to 98%.

[0055] Optionally, the nickel-based cis-butadiene rubber has a Mooney viscosity of 30 MU-50 MU, a branching factor of 15-20, a number average molecular weight (Mn) of 7.0 kg / mol-9.5 kg / mol, a weight average molecular weight (Mw) of 21.5 kg / mol-34.2 kg / mol, a molecular weight distribution (PDI) of 3.2-3.6, and a mass fraction of cis-1,4-structure in the nickel-based cis-butadiene rubber greater than 96%.

[0056] In the present application, by controlling the performance parameters of the rare earth cis-butadiene rubber and the nickel-based cis-butadiene rubber, the performance of the composite cis-butadiene rubber can be better controlled, and the mechanical properties and processing properties of the composite cis-butadiene rubber are further improved.

[0057] Optionally, the composite cis-butadiene rubber has a number average molecular weight (Mn) of 7.8 kg / mol-9.6 kg / mol, a weight average molecular weight (Mw) of 22.0 kg / mol-31.7 kg / mol, a molecular weight distribution (PDI) of 2.8-3.3, and a mass fraction of cis-1,4-structure in the composite cis-butadiene rubber greater than or equal to 96%, preferably 96%-98%. In this way, the composite cis-butadiene rubber has better processing properties and mechanical properties, and the viscosity of the glue solution is further reduced, the compatibility with syndiotactic 1,2-polybutadiene is further improved, and the reinforcing effect is further improved.

[0058] Optionally, the rare earth cis-butadiene rubber is selected from neodymium-based cis-butadiene rubber, and the neodymium-based cis-butadiene rubber is selected from branched neodymium-based cis-butadiene rubber. In this way, the composite cis-butadiene rubber has excellent mechanical properties, and its processing properties are further improved, so that the prepared cis-butadiene alloy has better mechanical properties and processing properties.

[0059] In step S2, the composite cis-butadiene rubber glue solution can be obtained in the following two ways:

[0060] The first way is to directly use the glue solution obtained in the preparation of the composite cis-butadiene rubber in step S1 as the composite cis-butadiene glue solution.

[0061] The second way is to dissolve the composite cis-butadiene rubber obtained in step S1 in an organic solvent to obtain a composite cis-butadiene rubber glue solution, wherein the organic solvent is selected from at least one of n-hexane, cyclohexane, cyclopentane, and n-heptane.

[0062] Considering that the impurity components in the glue solution obtained in the preparation of the composite cis-butadiene rubber in step S1 may affect the subsequent in-situ polymerization reaction, the second way is preferred in the present application.

[0063] In step S2, the composite cis-butadiene rubber glue solution and the butadiene monomer solution are mixed and subjected to in-situ polymerization in the presence of an iron-based catalyst or a cobalt-based catalyst.

[0064] Specifically, the complex butadiene rubber glue solution and the butadiene monomer solution are mixed uniformly, and then the iron-based catalyst or the cobalt-based catalyst is added to mix and initiate the polymerization reaction in situ to obtain a polymerized glue solution.

[0065] Optionally, the molar ratio of the complex butadiene rubber in the complex butadiene rubber glue solution to the butadiene monomer in the butadiene monomer solution is 3:2-19:1. In this way, the performance parameters such as the Mooney viscosity, the branching degree, and the molecular weight distribution of the butadiene rubber alloy can be better controlled, and the mechanical properties and the processing properties of the butadiene rubber alloy can be better improved.

[0066] Optionally, the polymerization temperature is 30-50℃, and the polymerization time is 30-60min. In this way, the polymerization reaction between the components can be fully carried out.

[0067] It can be understood that the catalyst system for the polymerization reaction of the complex butadiene rubber and the butadiene monomer in the present application can be an iron-based catalyst or a cobalt-based catalyst. The present application preferably uses a cobalt-based catalyst, which can effectively reduce the polymerization time and requires a low polymerization temperature, thereby being beneficial to energy saving and consumption reduction in production.

[0068] Specifically, when the iron-based catalyst is used, the molar ratio of the butadiene monomer in the butadiene monomer solution to the iron element in the iron-based catalyst is 5000:1-40000:1. In this way, the in-situ polymerization reaction efficiency can be better promoted.

[0069] The iron-based catalyst includes an iron compound, a phosphine-containing compound, and an alkyl aluminum, wherein the molar ratio of the iron compound, the phosphine-containing compound, and the alkyl aluminum is 1:3:10-1:20:50. In this way, the catalytic efficiency can be improved.

[0070] Further, the iron compound is selected from an organic iron compound, and the organic iron compound is selected from at least one of iron organic acids containing 1-20 carbon atoms, preferably iron benzoate, iron acetate, iron naphthenate, iron octanoate, iron neodecanoate, iron palmitate, iron stearate, iron acetylacetone, and iron salicylate.

[0071] The phosphine-containing compound is selected from at least one of phosphite compounds or phosphate compounds, preferably dimethyl phosphite, diethyl phosphite, dibutyl phosphite, diisooctyl phosphite, diphenyl phosphite, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, and triphenyl phosphine, more preferably at least one of diethyl phosphite, diisooctyl phosphite, and triphenyl phosphate.

[0072] The alkyl aluminum is selected from any one of trialkyl aluminum or methyl aluminum alkoxide, preferably at least one of trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trioctyl aluminum, more preferably triethyl aluminum, triisobutyl aluminum.

[0073] When the cobalt-based catalyst is used, the molar ratio of the butadiene monomer in the butadiene monomer solution to the cobalt element in the cobalt-based catalyst is 5000:1-40000:1. In this way, the polymerization rate is improved, the polymerization time is reduced, and the polymerization temperature is lower, which is beneficial to reduce energy consumption.

[0074] The cobalt-based catalyst comprises a soluble cobalt compound, alkyl aluminum and carbon disulfide, wherein the molar ratio of the soluble cobalt compound, the alkyl aluminum and the carbon disulfide is 1:10:2-1:100:20. In this way, the catalytic activity can be improved, and the catalytic efficiency can be better improved.

[0075] Further, the soluble cobalt compound is selected from organic acid cobalt, and the organic acid cobalt is selected from at least one of isooctanoic acid cobalt, naphthenic acid cobalt, neodecanoic acid cobalt, stearic acid cobalt, preferably isooctanoic acid cobalt.

[0076] The alkyl aluminum is selected from at least one of triethyl aluminum, trimethyl aluminum, triisobutyl aluminum, diethyl aluminum chloride, diisobutyl aluminum chloride, preferably triethyl aluminum.

[0077] In the present application, before the polymerization glue solution is coagulated, that is, after the in-situ polymerization reaction is completed, a terminating agent is added to the polymerization glue solution to terminate the reaction, wherein the terminating agent is an antioxidant / ethanol solution, and the antioxidant is selected from at least one of antioxidant 1076, antioxidant 1520, antioxidant B7802 and antioxidant 264.

[0078] Specifically, in step S3, the antioxidant solution is added to the polymerization glue solution to terminate the reaction, and then ethanol or water is added for coagulation, and then the mixture is placed in a vacuum drying box for drying to obtain the butadiene rubber alloy.

[0079] Meanwhile, the present application also provides a butadiene rubber alloy prepared by the above-mentioned preparation method of butadiene rubber alloy, which comprises a composite butadiene rubber and a syndiotactic 1,2-polybutadiene dispersed in the composite butadiene rubber.

[0080] The Mooney viscosity of the butadiene rubber alloy is 39MU-85MU, the branching factor is 3.5-8.5, the melting point is 196℃-203℃, the mass fraction of the syndiotactic 1,2-polybutadiene in the butadiene rubber alloy is 3.5%-30%, and the mass fraction of the cis-1,4-structure in the butadiene rubber alloy is 69%-95.5%.

[0081] Therefore, the butadiene rubber alloy has excellent wet skid resistance, tensile strength and tear strength, good processing performance and cold flow resistance, and can better meet the requirements of high strength and high modulus of the tire.

[0082] In addition, the application further provides a use of the butadiene rubber alloy in a tire.

[0083] Specifically, the butadiene rubber alloy of the application is mixed with polyisoprene rubber to be used as the sidewall rubber of the tire, and is used in the preparation of the sidewall of the tire. In the preparation process, the compatibility of the components in the rubber compound is improved, the dispersion of the carbon black is improved, and the dynamic fatigue performance, crack propagation resistance and weather resistance of the sidewall of the tire are improved, and the internal friction and heat generation of the sidewall of the tire are reduced, and the service life of the sidewall of the tire is improved.

[0084] In an embodiment, the butadiene rubber alloy is used in the preparation of the tread of the tire.

[0085] Hereinafter, the butadiene rubber alloy, the preparation method and the use thereof will be further described through the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the application, and should not be regarded as limiting the scope of the application. If the specific conditions are not indicated in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the manufacturer of the reagent or instrument is not indicated, it is a conventional product that can be obtained by purchase.

[0086] It should be pointed out that the number average molecular weight (Mn), the weight average molecular weight (Mw) and the molecular weight distribution (PDI) of the neodymium-based butadiene rubber, the nickel-based butadiene rubber, the composite butadiene rubber and the butadiene rubber alloy in the examples and comparative examples of the application are determined by gel permeation chromatography (GPC); the Mooney viscosity of the neodymium-based butadiene rubber, the nickel-based butadiene rubber, the composite butadiene rubber and the butadiene rubber alloy is determined by using the American ALPHA MV 2000 Mooney viscometer; and the branching factor of the neodymium-based butadiene rubber, the nickel-based butadiene rubber, the composite butadiene rubber and the butadiene rubber alloy is determined by using the RPA rubber processing analyzer, in addition, the melting point of the butadiene rubber alloy is determined by TA-Q200.

[0087] Example 1

[0088] The neodymium-based cis-butadiene rubber (40 MU in Mooney viscosity, 1.8 in branching factor, 8.9 kg / mol in Mn, 23.1 kg / mol in Mw, 2.6 in PDI, and 98% in mass fraction of cis-1,4-structure) and the nickel-based cis-butadiene rubber (30 in Mooney viscosity, 16 in branching factor, 7.0 kg / mol in Mn, 23.1 kg / mol in Mw, 3.3 in PDI, and 96% in mass fraction of cis-1,4-structure) are dissolved in n-hexane solution, then dichlorodisulfide coupling agent is added, and after mixing uniformly, the composite cis-butadiene rubber is separated, wherein the mass ratio of the neodymium-based cis-butadiene rubber and the nickel-based cis-butadiene rubber is 9:1, the mass ratio of the neodymium-based cis-butadiene rubber and the dichlorodisulfide coupling agent is 200:1, the Mooney viscosity of the composite cis-butadiene rubber is 38 MU, the branching factor is 5.5, the Mn is 8.6 kg / mol, the Mw is 24.1 kg / mol, the PDI is 2.8, and the mass fraction of cis-1,4-structure is 97.8%.

[0089] The composite cis-butadiene rubber obtained above is dissolved in n-hexane solution to obtain a composite cis-butadiene rubber glue solution; then butadiene hexane solution, cobalt isooctanoate, triethyl aluminum, and carbon disulfide are added to the composite cis-butadiene rubber glue solution and stirred uniformly, and polymerization reaction is carried out at 40°C for 30 min to obtain a polymerization glue solution, wherein the molar ratio of the composite cis-butadiene rubber in the composite cis-butadiene rubber glue solution and butadiene in the butadiene hexane solution is 100:22, the molar ratio of butadiene in the butadiene hexane solution and cobalt element in the cobalt isooctanoate is 15000:1, and the molar ratio of the cobalt isooctanoate, the triethyl aluminum, and the carbon disulfide is 1:70:10; then antioxidant B7802 / ethanol solution is added to the polymerization glue solution for termination, and ethanol solution is used for coagulation, and finally drying is carried out in a vacuum drying box to obtain a cis-butadiene rubber alloy. The Mooney viscosity of the cis-butadiene rubber alloy is 48 MU, the branching factor is 5.8, the melting point is 202°C, the mass fraction of intermediate 1,2-polybutadiene in the cis-butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the cis-butadiene rubber alloy is 87%.

[0090] The structure of the cis-butadiene rubber alloy of this embodiment is detected by using a Fourier infrared spectrometer, and the detection result is shown in Figure 1 From Figure 1 it can be seen that the structure of the cis-butadiene rubber alloy in this embodiment has polybutadiene chain segment characteristic peaks, wherein 738 cm -1 corresponds to the characteristic peak of cis-1,4-structure, 911 cm -1 corresponds to the characteristic peak of -1,2 structure, and 967 cm -1 corresponds to the characteristic peak of trans-1,4-structure.

[0091] At the same time, from Figure 2As can be seen, the butadiene rubber alloy in this embodiment has a melting point of 197℃.

[0092] Example 2

[0093] The neodymium butadiene rubber (Mooney viscosity of 35MU, branching factor of 1.8, Mn of 8.5kg / mol, Mw of 21.25kg / mol, PDI of 2.5, mass fraction of cis-1,4-structure of 98%) and nickel butadiene rubber (Mooney viscosity of 30MU, branching factor of 16, Mn of 7.0kg / mol, Mw of 22.54kg / mol, PDI of 3.22, mass fraction of cis-1,4-structure of 96%) were dissolved in n-hexane solution under nitrogen atmosphere, then dichlorodisulfide coupling agent was added, and after mixing, the composite butadiene rubber was separated, wherein the mass ratio of the neodymium butadiene rubber and the nickel butadiene rubber was 19:1, the mass ratio of the neodymium butadiene rubber and the dichlorodisulfide coupling agent was 1000:1, the Mooney viscosity of the composite butadiene rubber was 34.2MU, the branching factor was 3.0, the Mn was 8.3kg / mol, the Mw was 23.8kg / mol, the PDI was 2.87, and the mass fraction of cis-1,4-structure was 97.9%.

[0094] The composite butadiene rubber obtained above was dissolved in n-hexane solution to obtain a composite butadiene rubber solution; then butadiene hexane solution, cobalt isooctoate, triethylaluminum and carbon disulfide were added to the composite butadiene rubber solution and stirred uniformly, and polymerization reaction was carried out at 40℃ for 30min to obtain a polymerization solution, wherein the molar ratio of the composite butadiene rubber in the composite butadiene rubber solution and butadiene in the butadiene hexane solution was 100:7, the molar ratio of butadiene in the butadiene hexane solution and cobalt element in the cobalt isooctoate was 20000:1, and the molar ratio of the cobalt isooctoate, triethylaluminum and carbon disulfide was 1:30:20; then the polymerization solution was terminated by adding antioxidant B7802 / ethanol solution, and coagulation was carried out using ethanol solution, and finally drying was carried out in a vacuum drying box to obtain a butadiene rubber alloy. The Mooney viscosity of the butadiene rubber alloy was 39MU, the branching factor was 3.1, the melting point was 197℃, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy was 3.5%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy was 95.5%.

[0095] Example 3

[0096] The neodymium-based cis-butadiene rubber (the Mooney viscosity is 50MU, the branching factor is 1.7, Mn is 9.6kg / mol, Mw is 24kg / mol, PDI is 2.5, and the mass fraction of cis-1,4-structure is 98%) and the nickel-based cis-butadiene rubber (the Mooney viscosity is 45MU, the branching factor is 16, Mn is 9.0kg / mol, Mw is 30.6kg / mol, PDI is 3.4, and the mass fraction of cis-1,4-structure is 96%) are dissolved in the n-hexane solution under the nitrogen atmosphere, then the dichlorodisulfide coupling agent is added, and after being mixed uniformly, the composite cis-butadiene rubber is separated, wherein the mass ratio of the neodymium-based cis-butadiene rubber and the nickel-based cis-butadiene rubber is 4:1, the mass ratio of the neodymium-based cis-butadiene rubber and the dichlorodisulfide coupling agent is 125:1, the Mooney viscosity of the composite cis-butadiene rubber is 48MU, the branching factor is 7.1, Mn is 9.4kg / mol, Mw is 28.2kg / mol, PDI is 3.0, and the mass fraction of cis-1,4-structure is 97.6%.

[0097] The composite cis-butadiene rubber obtained above is dissolved in the n-hexane solution to obtain a composite cis-butadiene rubber glue solution; then the butadiene hexane solution, the cobalt isooctoate, the triethyl aluminum and the carbon disulfide are added into the composite cis-butadiene rubber glue solution and stirred uniformly, and the polymerization reaction is carried out at 50℃ for 30min to obtain a polymerization glue solution, wherein the molar ratio of the composite cis-butadiene rubber in the composite cis-butadiene rubber glue solution and the butadiene in the butadiene hexane solution is 100:39, the molar ratio of the butadiene in the butadiene hexane solution and the cobalt element in the cobalt isooctoate is 10000:1, and the molar ratio of the cobalt isooctoate, the triethyl aluminum and the carbon disulfide is 1:70:10; then the antioxidant B7802 / ethanol solution is added into the polymerization glue solution to terminate, and the ethanol solution is used for coagulation, and finally the vacuum drying box is used for drying to obtain the cis-butadiene rubber alloy. The Mooney viscosity of the cis-butadiene rubber alloy is 63MU, the branching factor is 7.5, the melting point is 202℃, the mass fraction of the intermediate cis-1,2-polybutadiene in the cis-butadiene rubber alloy is 20%, and the mass fraction of the cis-1,4-structure in the cis-butadiene rubber alloy is 79%.

[0098] Example 4

[0099] Example 4 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the mass ratio of the neodymium-based butadiene rubber and the nickel-based butadiene rubber is 3:2, the Mooney viscosity of the composite butadiene rubber is 36 MU, the branching factor is 20.8, Mn is 7.6 kg / mol, Mw is 23.7 kg / mol, PDI is 3.1, and the mass fraction of cis-1,4-structure is 97.2%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 47 MU, the branching factor is 12.5, the melting point is 197°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 87%.

[0100] Example 5

[0101] Example 5 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the branched neodymium-based butadiene rubber (Mooney viscosity is 40 MU, branching factor is 5.0, Mn is 9.1 kg / mol, Mw is 23.66 kg / mol, PDI is 2.6, and the mass fraction of cis-1,4-structure is 98%) is used instead of the neodymium-based butadiene rubber, the tin tetrachloride coupling agent is used instead of the dichlorodisulfide coupling agent, the mass ratio of the branched neodymium-based butadiene rubber and the nickel-based butadiene rubber is 9:1, the mass ratio of the branched neodymium-based butadiene rubber and the tin tetrachloride coupling agent is 500:1, the Mooney viscosity of the composite butadiene rubber is 36 MU, the branching factor is 7.1, Mn is 8.2 kg / mol, Mw is 23.3 kg / mol, PDI is 2.85, and the mass fraction of cis-1,4-structure is 97.8%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 44 MU, the branching factor is 8.5, the melting point is 198°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 87%.

[0102] Example 6

[0103] Example 6 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the molar ratio of the composite butadiene rubber and butadiene in the butadiene hexane solution is 1:1, the Mooney viscosity of the composite butadiene rubber is 38 MU, the branching factor is 5.5, Mn is 8.6 kg / mol, Mw is 24.1 kg / mol, PDI is 2.8, and the mass fraction of cis-1,4-structure is 97.8%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 85 MU, the branching factor is 8.5, the melting point is 197°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 30%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 70.3%.

[0104] Example 7

[0105] Example 7 is compared with Example 1, the only difference is that butadiene hexane solution, iron isooctoate, diethyl phosphite and triethyl aluminum are added into the compounded butadiene rubber solution and stirred uniformly, the molar ratio of butadiene in the butadiene hexane solution and iron in the iron isooctoate is 10000:1, the molar ratio of the iron isooctoate, diethyl phosphite and triethyl aluminum is 1:6:30, the rest conditions are the same, a butadiene rubber alloy is obtained, the Mooney viscosity of the butadiene rubber alloy is 45MU, the branching factor is 5.3, the melting point is 163℃, the mass fraction of the intermediate 1,2-polybutadiene in the butadiene rubber alloy is 10%, the mass fraction of the cis 1,4-structure in the butadiene rubber alloy is 87%.

[0106] Comparative Example 1

[0107] Comparative Example 1 is compared with Example 1, the only difference is that no dichlorodisulfide coupling agent is added in the step of preparing the compounded butadiene rubber, the Mooney viscosity of the compounded butadiene rubber is 39.6MU, the branching factor is 4, Mn is 8.8kg / mol, Mw is 25.6kg / mol, PDI is 2.91, the mass fraction of the cis 1,4-structure is 97.8%, the rest conditions are the same, a butadiene rubber alloy is obtained, the Mooney viscosity of the butadiene rubber alloy is 52MU, the branching factor is 4.7, the melting point is 197℃, the mass fraction of the intermediate 1,2-polybutadiene in the butadiene rubber alloy is 12%, the mass fraction of the cis 1,4-structure in the butadiene rubber alloy is 87%.

[0108] Comparative Example 2

[0109] Comparative Example 2 is compared with Example 1, the only difference is that the mass ratio of the neodymium-based butadiene rubber and the nickel-based butadiene rubber is 1:1 in the step of preparing the compounded butadiene rubber, the Mooney viscosity of the compounded butadiene rubber is 36MU, the branching factor is 11, Mn is 7.5kg / mol, Mw is 23.7kg / mol, PDI is 3.16, the mass fraction of the cis 1,4-structure is 97%, the rest conditions are the same, a butadiene rubber alloy is obtained, the Mooney viscosity of the butadiene rubber alloy is 45MU, the branching factor is 12, the melting point is 197℃, the mass fraction of the intermediate 1,2-polybutadiene in the butadiene rubber alloy is 12%, the mass fraction of the cis 1,4-structure in the butadiene rubber alloy is 87%.

[0110] Comparative Example 3

[0111] Comparative Example 3 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the mass ratio of the neodymium-based butadiene rubber and the nickel-based butadiene rubber is 2:3, the Mooney viscosity of the composite butadiene rubber is 34 MU, the branching factor is 15, Mn is 7.5 kg / mol, Mw is 24.2 kg / mol, PDI is 3.22, and the mass fraction of cis-1,4-structure is 96.8%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 44 MU, the branching factor is 16, the melting point is 200°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 87%.

[0112] Comparative Example 4

[0113] Comparative Example 4 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the neodymium-based butadiene rubber is replaced by the nickel-based butadiene rubber of the same mass as in Example 1, i.e., only containing nickel-based butadiene rubber, the Mooney viscosity of the composite butadiene rubber is 42 MU, the branching factor is 20, Mn is 8.9 kg / mol, Mw is 31.15 kg / mol, PDI is 3.5, and the mass fraction of cis-1,4-structure is 96.8%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 52 MU, the branching factor is 21.2, the melting point is 196°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 87%.

[0114] Comparative Example 5

[0115] Comparative Example 5 is the same as Example 1 except that in the step of preparing the composite butadiene rubber, the nickel-based butadiene rubber is replaced by the neodymium-based butadiene rubber of the same mass as in Example 1, i.e., only containing neodymium-based butadiene rubber, the Mooney viscosity of the composite butadiene rubber is 58 MU, the branching factor is 6.2, Mn is 9.9 kg / mol, Mw is 31.18 kg / mol, PDI is 3.15, and the mass fraction of cis-1,4-structure is 98%, and the rest of the conditions are the same, to obtain a butadiene rubber alloy, wherein the Mooney viscosity of the butadiene rubber alloy is 69 MU, the branching factor is 9.6, the melting point is 197°C, the mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy is 12%, and the mass fraction of cis-1,4-structure in the butadiene rubber alloy is 87%.

[0116] Comparative Example 6

[0117] Comparative Example 6 is the same as Example 1 except that in the step of preparing the compounded butadiene rubber, the same mass of natural rubber is used instead of neodymium-based butadiene rubber, the compounded butadiene rubber has a Mooney viscosity of 65 MU, a branching factor of 6.5, Mn of 20.7 kg / mol, Mw of 57.7 kg / mol, PDI of 2.78, and a mass fraction of cis-1,4-structure of 97%, and the remaining conditions are the same, to obtain a butadiene rubber alloy, wherein the butadiene rubber alloy has a Mooney viscosity of 70 MU, a branching factor of 7.9, a melting point of 197°C, a mass fraction of meso-1,2-polybutadiene in the butadiene rubber alloy of 12%, and a mass fraction of cis-1,4-structure in the butadiene rubber alloy of 87%.

[0118] The butadiene rubber alloys prepared in Examples 1-7 and Comparative Examples 1-6, respectively, are made into a mixed rubber, and the specific preparation method is as follows:

[0119] 100 parts by weight of the butadiene rubber alloy is added to a mixed rubber device, and is opened for 2 min, then 2 parts by weight of stearic acid and 3 parts by weight of zinc oxide are added, and is opened for 2 min, then 30 parts by weight of carbon black and parts by weight of are added, and is opened for 16 min, then 30 parts by weight of carbon black is continuously added, and is opened for 11 min, and finally 0.9 parts by weight of a vulcanization accelerator TBBS and 1.5 parts by weight of sulfur are added, and is opened for 5 min to obtain a mixed rubber, then the mixed rubber is pressed into a rubber sheet, then the rubber sheet is cut to obtain a rubber sheet with a size of 12 mm x 12 mm, then the obtained rubber sheet is vulcanized to obtain a vulcanized sheet with a size of 12 mm x 12 mm, and finally the vulcanized sheet is made into a dumbbell-shaped sample, i.e., a mixed rubber, wherein the width of the dumbbell-shaped sample is 6 mm, and the thickness is 2 mm.

[0120] At the same time, the Mooney viscosity of the mixed rubber obtained above is determined by using a dynamic mechanical analyzer (DMA) of Q800 of TA Instruments, wherein the processing performance of the mixed rubber is characterized by the size of the Mooney change value, the larger the Mooney change value, the worse the processing performance of the mixed rubber, and the Mooney change value is the difference between the Mooney viscosity of the mixed rubber and the Mooney viscosity of the butadiene rubber alloy, and the determination results are shown in Table 1.

[0121] Table 1

[0122]

[0123]

[0124] In addition, the above obtained rubber compound is tested for performance, wherein the tensile strength, elongation at break and 300% modulus are used to characterize the mechanical properties of the rubber compound, the 60℃ tan delta is used to characterize the rolling resistance of the rubber compound, the smaller the 60℃ tan delta value, the smaller the rolling resistance of the rubber compound, the 0℃ tan delta is used to characterize the wet skid resistance of the rubber compound, the larger the 0℃ tan delta value, the better the wet skid resistance of the rubber compound, the 60℃ loss modulus is used to characterize the heat resistance of the rubber compound, the smaller the 60℃ loss modulus, the better the heat resistance of the rubber compound, and the test results are shown in Tables 2-3, wherein the specific test methods are as follows:

[0125] Tensile strength: according to GBT528-2009 standard;

[0126] Elongation at break: according to GBT528-2009 standard;

[0127] 300% modulus: according to GBT528-2009 standard.

[0128] Table 2

[0129]

[0130] Table 3

[0131]

[0132] The technical features of the above embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0133] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent protection of the present application should be subject to the appended claims.

Claims

1. A process for the preparation of a butadiene rubber alloy, characterized in that, The method comprises the following steps: The rare earth butadiene rubber, nickel butadiene rubber, coupling agent and organic solvent are mixed and coupled to obtain a composite butadiene rubber, wherein the mass of the rare earth butadiene rubber is greater than that of the nickel butadiene rubber, the Mooney viscosity of the composite butadiene rubber is 35MU-55MU, the branching factor is 3.0-7.1, the mass ratio of the rare earth butadiene rubber to the nickel butadiene rubber is 4:1-19:1, the mass ratio of the rare earth butadiene rubber to the coupling agent is 125:1-1000:1, and the coupling agent is at least one of divinyl dimethyl silane, triethoxysilane, 3-chloropropyl triethoxysilane, 4-chloropropyl methyl dimethoxysilane, 3-chloropropyl methyl diethoxysilane, bis-[gamma-(triethoxysil) propyl] tetrasulfide, n-propyl trichlorosilane, silicon tetrachloride, tin tetrachloride and dichlorodisulfide; The composite butadiene rubber solution and a butadiene monomer solution are mixed and subjected to in-situ polymerization in the presence of an iron catalyst or a cobalt catalyst to prepare syndiotactic 1,2-polybutadiene, thereby obtaining a polymerization solution, wherein the molar ratio of the composite butadiene rubber in the composite butadiene rubber solution to the butadiene monomer in the butadiene monomer solution is 3:2 to 19:1; The polymerization solution is subjected to coagulation and drying to obtain a butadiene rubber alloy.

2. The process for preparing a butadiene rubber alloy according to claim 1, characterized in that, In the step of coupling the rare earth butadiene rubber and the nickel butadiene rubber to obtain a composite butadiene rubber, at least one of the following conditions is satisfied: (1) the Mooney viscosity of the rare earth butadiene rubber is 30MU-50MU, the branching factor is 1.5-2.0, the number average molecular weight is 8.0kg / mol-10.0kg / mol, the weight average molecular weight is 16.0kg / mol-30.0kg / mol, the molecular weight distribution is 2.0-3.0, and the mass fraction of cis-1,4-structure in the rare earth butadiene rubber is greater than or equal to 98%; (2) the Mooney viscosity of the nickel butadiene rubber is 30MU-50MU, the branching factor is 15-20, the number average molecular weight is 7.0kg / mol-9.5kg / mol, the weight average molecular weight is 21.5kg / mol-34.2kg / mol, the molecular weight distribution is 3.2-3.6, and the mass fraction of cis-1,4-structure in the nickel butadiene rubber is greater than 96%; (3) the number average molecular weight of the composite butadiene rubber is 7.8kg / mol-9.6kg / mol, the weight average molecular weight is 22.0kg / mol-31.7kg / mol, the molecular weight distribution is 2.8-3.3, and the mass fraction of cis-1,4-structure in the composite butadiene rubber is greater than or equal to 96%; (4) the rare earth butadiene rubber is selected from neodymium butadiene rubber.

3. The process for preparing a butadiene rubber alloy according to claim 1, characterized in that, In the step of mixing the composite butadiene rubber solution and the butadiene monomer solution and subjecting to in-situ polymerization, the polymerization temperature is 30℃-50℃, and the polymerization time is 30min-60min.

4. The process for preparing a butadiene rubber alloy according to claim 1, characterized in that, When the composite cis-butadiene rubber glue solution and the butadiene monomer solution are mixed and in-situ polymerization is carried out in the presence of the iron-based catalyst, at least one of the following conditions is also met: (1) the molar ratio of butadiene monomer in the butadiene monomer solution to iron in the iron-based catalyst is 5000:1 to 40000:1; (2) the iron-based catalyst comprises an iron compound, a phosphine-containing compound and an alkyl aluminum, wherein the molar ratio of the iron compound, the phosphine-containing compound and the alkyl aluminum is 1:3:10 to 1:20:

50.

5. The process for preparing a butadiene rubber alloy according to claim 4, characterized in that, When the composite cis-butadiene rubber glue solution and the butadiene monomer solution are mixed and in-situ polymerization is carried out in the presence of the cobalt-based catalyst, at least one of the following conditions is also met: (1) the molar ratio of butadiene monomer in the butadiene monomer solution to cobalt in the cobalt-based catalyst is 5000:1 to 40000:1; (2) the cobalt-based catalyst comprises a soluble cobalt compound, an alkyl aluminum and carbon disulfide, wherein the molar ratio of the soluble cobalt compound, the alkyl aluminum and the carbon disulfide is 1:10:2 to 1:100:

20.

6. A cis-butadiene rubber alloy obtainable by the process according to any one of claims 1 to 5, characterized in that The cis-butadiene rubber alloy comprises a composite cis-butadiene rubber and syndiotactic 1,2-polybutadiene dispersed in the composite cis-butadiene rubber.

7. The butadiene rubber alloy according to claim 6, characterized in that The cis-butadiene rubber alloy has a Mooney viscosity of 39MU-85MU, a branching factor of 3.5-8.5, a melting point of 196℃-203℃, a mass fraction of syndiotactic 1,2-polybutadiene in the cis-butadiene rubber alloy of 3.5%-30%, and a mass fraction of cis-1,4-structure in the cis-butadiene rubber alloy of 69%-95.5%.

8. Use of the cis-butadiene rubber alloy according to claim 6 or claim 7 in a tire.

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