High cis-polybutadiene elastomer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polyolefin elastomers, and discloses a high cis-polybutadiene elastomer as well as a preparation method and application thereof. The molar content of a cis structure of the polybutadiene elastomer is not less than 95%, and the weight-average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol, or the viscosity-average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol; the raw rubber strength of the polybutadiene elastomer is not less than 130 kPa, and after the polybutadiene elastomer is placed at room temperature for 960 hours, the height retention rate of the raw rubber is not less than 75%. According to the invention, butadiene polymerization is carried out under the action of the catalyst and the silicon-containing compound, so that the polybutadiene elastomer with high raw rubber strength and excellent cold flow resistance can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of polyolefin elastomers, and in particular to a high-cis polybutadiene elastomer and a preparation method and application thereof. Background Art

[0002] High cis polybutadiene, whose molecular chain is mainly composed of cis-structured butadiene structural units, has excellent elasticity, wear resistance and flex resistance. For example, cis-butadiene rubber with a cis-structure content of more than 95% is the second largest synthetic rubber variety, used to manufacture tires, modified plastics, conveyor belts, hoses or soles, etc., and is one of the important basic materials indispensable for manufacturing tires. Since the industrialization of nickel-based cis-butadiene rubber in my country in 1971, the current production capacity is about 1.6 million tons / year, but the brand is single (BR9000) and the technical indicators have basically not changed much. However, due to the softness of its macromolecular chain and the weak interaction between the molecular chains, the relative displacement and sliding of the molecular chains cannot be hindered, resulting in the cold flow phenomenon of raw rubber during storage or transportation, causing the shape of the rubber block to change, and also causing the packaging bag to burst or cause the cargo stacking to collapse. It is reported that the height retention rate of commercial nickel-based cis-1,4-butadiene rubber BR9000 after being placed at room temperature for 20 hours is only 72% due to cold flow, which indicates that the cold flow of nickel-based cis-1,4-butadiene rubber BR9000 is extremely serious (see: Elastomer, 2000, (01): 21-23).

[0003] In addition, the raw strength of cis-1,4-butadiene rubber is largely governed by the mobility of molecular segments and has a great correlation with the internal friction between molecular chains. For nickel-based cis-1,4-butadiene rubber, there are many short-chain branched structures on its molecular chain, resulting in small intermolecular forces and low raw strength. It is easy to break when the mixed rubber is pressed out. It is usually used in combination with other types of rubber to increase its strength. It is reported that the raw strength of commercial nickel-based cis-1,4-butadiene rubber BR9000 is only 70-120 kPa (see: Yanshan Petrochemical, 1982, (03): 136-141).

[0004] In the prior art, two methods, in-situ modification and post-modification, are usually used to improve the cold flow resistance of nickel-based butadiene rubber and increase the raw rubber strength.

[0005] The in-situ modification method is a method of introducing a branching agent into a catalyst system to directly prepare modified butadiene rubber by one-step polymerization. US5451646A and US6586542B2 respectively disclose the preparation of branched butadiene rubber by adding a branching agent and a molecular weight regulator such as p,p'-distyrenated diphenylamine or diethyl zinc into a catalyst component, but this results in a reduction in the molecular weight and Mooney viscosity of the polymerized product, thereby adversely affecting the cold flow resistance and mechanical strength of the butadiene rubber. In order to improve the adverse effects of the molecular weight reduction on cold flow and strength caused by the above methods, US20060047033A1 and CN107793534A also disclose the addition of alkylated diphenylamine or liquid polybutadiene as a branching agent into the catalyst component, which can improve the cold flow resistance of nickel-based butadiene rubber to a certain extent without significantly affecting the molecular weight of the polymerized product, but reduces the mechanical strength of the nickel-based butadiene rubber raw rubber.

[0006] The post-modification method is to improve the cold flow resistance and increase the raw rubber strength by constructing cross-linking points between the prepared butadiene rubber macromolecular chains or introducing a rigid molecular structure.

[0007] CN105985457A discloses a method for preventing cold flow of butadiene rubber. The method comprises mixing butadiene rubber with a peroxide anti-cold flow agent (such as tri-pentyl peroxypivalate) solution, and improving the anti-cold flow performance of butadiene rubber by generating a cross-linked structure between molecular chains through peroxide. However, a small amount of residual peroxide anti-cold flow agent in the rubber may also cause degradation and chain breakage of macromolecular chains, thereby affecting the performance stability of the rubber material.

[0008] CN104231119A discloses a method for preparing long-chain branched high-cis polybutadiene, which comprises carrying out a click chemistry reaction between linear polybutadiene and a compound containing a thiol group in the presence of a free radical initiator, erecting a fulcrum between polybutadiene macromolecular chains, and forming high molecular weight high-cis long-chain branched polybutadiene with different degrees of branching. Due to its long-chain branched chain structure, it can effectively coat inorganic fillers, improve the dispersion of fillers, and significantly enhance the mixing effect with fillers such as carbon black. However, the influence on the cold flow performance and strength of raw rubber is not mentioned.

[0009] CN104610509A discloses a modified butadiene rubber and a modification method thereof, wherein N-vinyl pyrrolidone and an initiator are added to a polybutadiene solution to graft N-vinyl pyrrolidone onto the butadiene rubber macromolecular chain. This technology does not mention the improvement of the raw rubber strength and cold flow resistance of butadiene rubber.

[0010] In summary, the shortcomings of the prior art are mainly:

[0011] In the polymerization reaction system, liquid polybutadiene or alkylated diphenylamine is used as a branching agent to carry out butadiene polymerization reaction. Under the premise of ensuring the molecular weight of the polymerization product, the cold flow resistance of the raw rubber is improved to a certain extent, but the strength of the raw rubber is not improved. In the post-modification method of butadiene rubber, the residual peroxide anti-cold flow agent will affect the stability of the performance of the butadiene rubber product. Summary of the invention

[0012] The purpose of the present invention is to solve the problem that the polybutadiene elastomer in the prior art cannot take into account both the cold flow property and the strength of the raw rubber.

[0013] In order to achieve the above-mentioned object, the first aspect of the present invention provides a polybutadiene elastomer, wherein the molar content of the cis structure of the polybutadiene elastomer is not less than 95%, the weight average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol, or the viscosity average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol; the raw rubber strength of the polybutadiene elastomer is not less than 130 kPa, and the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960 hours is not less than 75%.

[0014] The second aspect of the present invention provides a method for preparing the polybutadiene elastomer described in the first aspect, the method comprising: polymerizing butadiene monomer in the presence of a catalyst and a silicon-containing compound;

[0015] The silicon-containing compound is a vinyl silane compound and / or nano silicon dioxide, and the molar ratio of the silicon-containing compound to the butadiene monomer is 0.0001-0.05:1.

[0016] The third aspect of the present invention provides the use of the polybutadiene elastomer described in the first aspect in tires, plastic modification, conveyor belts, hoses, soles, seals or golf ball cores.

[0017] Through the above technical scheme, the polybutadiene elastomer and preparation method provided by the present invention have the following beneficial effects:

[0018] (1) The high cis-polybutadiene elastomer (or butadiene rubber) provided by the present invention has excellent raw rubber cold flow resistance and raw rubber strength. In particular, the height retention rate of the raw polybutadiene elastomer after being placed at room temperature for 960 hours is still not less than 75%.

[0019] (2) The present invention obtains a high cis polybutadiene elastomer by a one-step polymerization method under the action of a catalyst and a silicon-containing compound, while improving the cold flow resistance and strength of the raw rubber. The height retention rate of the polybutadiene elastomer raw rubber after being placed at room temperature for 960 hours is still not less than 75%, and the raw rubber strength is not less than 130 kPa.

[0020] (3) The preparation method provided by the present invention does not require the introduction of branching additives or peroxide reagents, thereby avoiding the adverse effects of additives on raw rubber properties or product stability. In addition, the polymerization method provided by the present invention is simple and easy to implement, reduces the steps of the post-modification method, and saves energy and reduces consumption.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0022] 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.

[0023] In the present invention, unless otherwise specified, the room temperature or normal temperature refers to 25±2°C.

[0024] As mentioned above, the first aspect of the present invention provides a polybutadiene elastomer, the molar content of the cis structure of the polybutadiene elastomer is not less than 95%, the weight average molecular weight of the polybutadiene elastomer is not less than 100kg / mol, or the viscosity average molecular weight of the polybutadiene elastomer is not less than 100kg / mol; the raw rubber strength of the polybutadiene elastomer is not less than 130kPa, and the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960h is not less than 75%.

[0025] Preferably, in the polybutadiene elastomer, the molar content of the cis structure is not less than 96%.

[0026] Preferably, the weight average molecular weight of the polybutadiene elastomer is not less than 150 kg / mol, more preferably not less than 200 kg / mol; or

[0027] The viscosity average molecular weight of the polybutadiene elastomer is not less than 150 kg / mol, more preferably not less than 200 kg / mol.

[0028] Preferably, the green strength of the polybutadiene elastomer is not less than 150 kPa, more preferably not less than 170 kPa.

[0029] Preferably, the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960 hours is not less than 80%. More preferably, the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960 hours is not less than 85%.

[0030] As mentioned above, the second aspect of the present invention provides a method for preparing the polybutadiene elastomer described in the first aspect, the method comprising: polymerizing butadiene monomer in the presence of a catalyst and a silicon-containing compound;

[0031] The silicon-containing compound is a vinyl silane compound and / or nano silicon dioxide, and the molar ratio of the silicon-containing compound to the butadiene monomer is 0.0001-0.05:1.

[0032] The inventors of the present invention discovered during the research process that by adding a silicon-containing compound in a specific ratio during the synthesis of a polybutadiene elastomer and adopting the method provided by the present invention, a polybutadiene elastomer with excellent raw rubber cold flow resistance can be prepared; at the same time, the polybutadiene elastomer prepared by the method provided by the present invention can also significantly improve the raw rubber strength; in addition, the polybutadiene elastomer prepared by the method provided by the present invention can also improve the mixing effect of raw rubber and filler, increase the combined rubber content of the mixed rubber, and improve the physical and mechanical properties of the vulcanized rubber.

[0033] Preferably, the molar ratio of the silicon-containing compound to the butadiene is 0.0008-0.04:1, more preferably 0.001-0.03:1.

[0034] According to a particularly preferred embodiment of the present invention, the molar ratio of the silicon-containing compound to the butadiene monomer is 0.002-0.0045: 1. The inventors found during the research process that the polybutadiene elastomer prepared by adopting the specific embodiment of this preferred case has better green strength.

[0035] Preferably, the vinyl silane compound is selected from at least one of dimethyl (4-vinylphenyl) silane, trimethyl (4-vinylphenyl) silane, vinyl triphenyl silane, vinyl dimethyl chlorosilane, vinyl methyl dichlorosilane, vinyl dimethyl ethoxy silane, vinyl dimethoxymethyl silane, vinyl trimethoxy silane, trimethoxy (4-vinylphenyl) silane, vinyl methyl diethoxy silane, vinyl triethoxy silane, vinyl triisopropoxy silane, vinyl tri-tert-butoxy silane, vinyl tris (dimethylsiloxy) silane, vinyl tris (trimethylsiloxy) silane, vinyl tris (2-methoxyethoxy) silane, vinyl methyl bis (trimethylsiloxy) silane and vinyl tributanoximo silane.

[0036] According to a particularly preferred embodiment of the present invention, the vinyl silane compound is selected from at least one of dimethyl (4-vinylphenyl) silane, trimethyl (4-vinylphenyl) silane, vinyl trimethoxy silane, trimethoxy (4-vinylphenyl) silane, vinyl methyl diethoxy silane and vinyl triethoxy silane. The inventors found in the research process that by adopting the preferred embodiment, a polybutadiene elastomer with better comprehensive performance can be obtained.

[0037] The present invention has no special requirements on the type and source of the catalyst, and any catalyst known in the art can be used, for example, a nickel-based catalyst, a cobalt-based catalyst, or a rare earth neodymium-based catalyst. For example, the catalyst can be a nickel-based catalyst prepared by the method in CN101580560A and CN108929400A. For example, the nickel-based catalyst contains a nickel carboxylate, an organic aluminum compound, and a boron trifluoride complex; or the catalyst can be prepared by the method in CN1840552A, The rare earth catalyst prepared by the method in CN104231133A and CN108929396A, illustratively, contains an active component, an organoaluminum compound and a halide; alternatively, a cobalt-based catalyst prepared by the method in CN101084265A, US3135725A and CA795860A can also be used, illustratively, the cobalt-based catalyst contains a cobalt carboxylate, an organoaluminum compound and water; the present invention will not be described one by one here, and those skilled in the art should not be construed as limiting the present invention.

[0038] It should be noted that, in the method provided by the present invention, when the polymerization reaction temperature is low, the polymerization reaction time can be prolonged; when the polymerization reaction temperature is high, the polymerization time can be effectively shortened.

[0039] Preferably, the polymerization reaction conditions at least include: a reaction temperature of -20°C to 120°C, and a reaction time of 0.5h to 30h. More preferably, the polymerization reaction conditions at least include: a reaction temperature of 10°C to 110°C, and a reaction time of 1h to 20h. Further preferably, the polymerization reaction conditions at least include: a reaction temperature of 20°C to 100°C, and a reaction time of 1.5h to 15h.

[0040] According to a particularly preferred embodiment of the present invention, the catalyst is a nickel-based catalyst containing nickel carboxylate, an organic aluminum compound and a boron trifluoride complex.

[0041] Preferably, in the nickel-based catalyst, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound calculated as aluminum, the boron trifluoride complex calculated as boron, and the butadiene is 5.0×10-6 -2.0×10 -3 :5.0×10 -6 -6.0×10 -2 :5.0×10 -6 -1.0×10 -1 : 1, more preferably 8.0×10 -6 -1.0×10 -3 :1.6×10 -5 -2.5×10 -2 :2.4×10 -5 -3.0×10 -2 :1.

[0042] The present invention has no special requirements on the order of feeding materials in the polymerization reaction process, and the polymerization reaction can be carried out by methods known in the art.

[0043] Preferably, the specific operation method of the polymerization reaction includes: first mixing the mixed aged liquid of the nickel carboxylate and the organoaluminum compound with the butadiene monomer solution to obtain a mixed solution I, then contacting the mixed solution I with a boron trifluoride complex to carry out a polymerization reaction to obtain a polymer solution, and contacting the polymer solution with a silicon-containing compound for reaction.

[0044] Preferably, the specific operation method of the polymerization reaction includes: first mixing the first part of the silicon-containing compound with butadiene monomer to obtain a mixed solution I, then polymerizing the mixed aged solution of the nickel carboxylate and the organic aluminum compound with the mixed solution I to obtain a polymer solution, and contacting the polymer solution, the boron trifluoride complex and the second part of the silicon-containing compound for reaction; wherein the molar ratio of the first part of the silicon-containing compound to the second part of the silicon-containing compound is 0.03-1.5:1.

[0045] Preferably, the specific operation method of the polymerization reaction includes: firstly mixing the first part of the organic aluminum compound with the first part of the silicon-containing compound to obtain a mixed solution I, mixing the mixed solution I with a butadiene monomer solution to obtain a mixed solution II, and then sequentially contacting the nickel carboxylate with the mixed aging solution of the second part of the organic aluminum compound and the boron trifluoride complex with the mixed solution II to carry out the polymerization reaction to obtain a polymer solution, and contacting the polymer solution with the second part of the silicon-containing compound for reaction; wherein the molar ratio of the first part of the silicon-containing compound to the second part of the silicon-containing compound is 0.03-1.5:1, and the molar ratio of the first part of the organic aluminum compound to the second part of the organic aluminum compound is 0.1-293.3:1.

[0046] Preferably, the specific operation method of the polymerization reaction includes: first mixing the organic aluminum compound in the catalyst with the silicon-containing compound to obtain a mixed solution I, then mixing the nickel carboxylate in the catalyst with the mixed solution I to obtain a mixed solution II, and finally contacting the mixed solution II with the boron trifluoride complex and butadiene monomer in the catalyst to carry out the polymerization reaction.

[0047] Preferably, the specific operation method of the polymerization reaction includes: first mixing the nickel carboxylate in the catalyst with the organic aluminum compound to obtain a mixed solution I, and mixing the mixed solution I with butadiene to obtain a mixed solution II; and mixing the boron trifluoride complex in the catalyst with a silicon-containing compound to obtain a mixed solution III, and finally contacting the mixed solution II with the mixed solution III to carry out the polymerization reaction.

[0048] Preferably, the specific operation method of the polymerization reaction includes: mixing the boron trifluoride complex, the silicon-containing compound, and butadiene in the catalyst to obtain a mixed solution I; mixing the nickel carboxylate and the organic aluminum compound in the catalyst to obtain a mixed solution II; and finally contacting the mixed solution I with the mixed solution II to carry out the polymerization reaction.

[0049] Preferably, the specific operation method of the polymerization reaction includes: mixing the boron trifluoride complex in the catalyst with the silicon-containing compound to obtain a mixed solution I, and mixing the mixed solution I with butadiene to obtain a mixed solution II; and mixing the nickel carboxylate in the catalyst with an organic aluminum compound to obtain a mixed solution III; finally, contacting the mixed solution II with the mixed solution III to carry out the polymerization reaction.

[0050] In a preferred embodiment, the specific operation method of the polymerization reaction includes: mixing the boron trifluoride complex in the catalyst with the silicon-containing compound to obtain a mixed solution I, and mixing the mixed solution I with butadiene to obtain a mixed solution II; and mixing the nickel carboxylate in the catalyst with an organic aluminum compound to obtain a mixed solution III; contacting the mixed solution II with the mixed solution III to carry out the polymerization reaction to obtain a mixed solution IV, and finally adding nano silicon dioxide to the mixed solution IV. The inventors have found that in the specific implementation of this preferred embodiment, while ensuring mechanical strength, the polybutadiene elastomer is given excellent anti-cold flow performance and green strength.

[0051] According to another particularly preferred embodiment of the present invention, the catalyst is a rare earth catalyst, and the specific operation method of the polymerization reaction includes: mixing a silicon-containing compound with butadiene to obtain a mixed solution I, and contacting a rare earth catalyst with the mixed solution I to carry out the polymerization reaction.

[0052] According to another particularly preferred embodiment of the present invention, the catalyst is a cobalt-based catalyst, and the specific operation method of the polymerization reaction includes: mixing a silicon-containing compound with butadiene to obtain a mixed solution I, and contacting the cobalt-based catalyst with the mixed solution I to carry out the polymerization reaction.

[0053] It should be noted that, at the end of the polymerization reaction, water, alcohols or phenolic compounds can be used as terminators to terminate the reaction, and the present invention has no special requirements on the amount of the terminator, as long as it can achieve the purpose of terminating the reaction. Preferably, the terminator is an ethanol solution containing 1-3wt% antioxidant 1076.

[0054] The present invention has no special requirements on the reaction equipment and operation mode of the polymerization reaction, and the polymerization reaction can be carried out using equipment and operation modes known in the art. For example, the polymerization reaction can be carried out in a single polymerization reactor device, or in a multi-polymerization reactor device in series. For the operation mode of the polymerization reaction, a continuous polymerization or intermittent polymerization operation mode can be adopted, and a bulk polymerization or solution polymerization operation mode can also be adopted. When a solution polymerization method is adopted, a hydrocarbon compound is used as a polymerization solvent. For example, the polymerization solvent is selected from at least one of n-hexane, cyclohexane, heptane, and methylcyclohexane.

[0055] Preferably, the polymerization reaction is carried out under the protection of an inert atmosphere.

[0056] Preferably, the method further comprises: eluting the polymer solution obtained by the polymerization reaction in an aqueous medium with a pH value of 5.0-10.0, and washing the eluted product with water and then drying it.

[0057] Preferably, the volume ratio of the polymer solution to the aqueous medium is 1-100:100, preferably 2-80:100, and more preferably 5-60:100.

[0058] Preferably, the conditions of the elution treatment include at least: a temperature of 20°C to 100°C, and a time of 1 min to 600 min. More preferably, the conditions of the elution treatment include at least: a temperature of 30°C to 100°C, and a time of 5 min to 600 min.

[0059] Preferably, the pH value of the aqueous medium is 6.5-9.0.

[0060] Preferably, the drying treatment conditions include at least: a temperature of 20° C. to 100° C. and a time of at least 5 minutes.

[0061] As mentioned above, the third aspect of the present invention provides the use of the polybutadiene elastomer described in the first aspect in tires, plastic modification, conveyor belts, hoses, soles, seals or golf ball cores.

[0062] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0063] Silicon-containing compound 1: vinyltrimethoxysilane;

[0064] Silicon-containing compound 2: vinyltriethoxysilane;

[0065] Silicon-containing compound 3: fumed silica;

[0066] In the following examples, unless otherwise stated, the nickel-based catalyst adopts the catalyst system in CN101580560A, and the specific preparation process refers to the preparation method in CN101580560A.

[0067] Nickel Catalysts

[0068] Organoaluminum compound I: triisobutylaluminum;

[0069] Organoaluminum compound II: diisobutylaluminum hydride;

[0070] Nickel carboxylate: nickel naphthenate;

[0071] Boron trifluoride complex I: a complex of boron trifluoride with 3-decanol and 2,4-pentanedione, wherein the ratio of 3-decanol to 2,4-pentanedione is 1:1;

[0072] Boron trifluoride complex II: a complex of boron trifluoride with 2-dodecanol, 2-tridecanone and dibutyl oxalate, wherein the ratio of 2-dodecanol: 2-tridecanone: dibutyl oxalate is 1: 0.8: 0.2;

[0073] Boron trifluoride complex III: complex of boron trifluoride and diethyl ether.

[0074] In the following examples, the microstructure content of the polymer was determined using an American Nicolet 6700 infrared spectrometer (FTIR), and the cis structure content was obtained by referring to the standard SHT 1727-2017 (Infrared spectroscopic method for determination of microstructure of butadiene rubber);

[0075] The Wyatt LabAlliance series 1500 gel permeation chromatograph was used, equipped with a multi-angle laser light scattering detector (MALS, DAWN HELEOS-Ⅱ), a viscosity detector (VIS, ViscoStar-Ⅱ), a differential refractive index detector (RI, Optilab T-rEX), and four Mz-Gel Four chromatographic columns were used to obtain the polymer weight-average molecular weight and distribution index.

[0076] Calculation of polymerization yield: The polymer solution is condensed in hot water, and the unreacted monomers and solvent are removed to obtain a polymerization product. After separation, the polymerization product is dried in a vacuum oven at 40°C to a constant weight to obtain a polybutadiene product. The polymerization yield is the ratio of the mass of the polybutadiene product to the mass of the butadiene monomer.

[0077] Example 1

[0078] This embodiment provides a method for preparing a polybutadiene elastomer, the method comprising:

[0079] Prepare a butadiene-n-hexane solution with a butadiene concentration of 3.26 mol / L for later use;

[0080] Under nitrogen protection, 2.45 mmol of organoaluminum compound I (the molar ratio of organoaluminum compound I to butadiene is 0.00075:1) and 14.67 mmol of silicon-containing compound 1 (the molar ratio of silicon-containing compound 1 to butadiene is 0.0045:1) are first mixed to obtain a mixed solution I;

[0081] The mixed solution I is mixed with 1000 mL of the aforementioned butadiene-n-hexane solution (butadiene concentration is 3.26 mol / L) to obtain a mixed solution II;

[0082] 0.39 mmol of nickel carboxylate and 1.96 mmol of organoaluminum compound I were mixed at 30°C and reacted for 0.5 h to obtain a mixed solution III of the two;

[0083] The boron trifluoride complex I is contacted with the mixed solution II and the mixed solution III, and the polymerization reaction is carried out at 50°C for 5 hours. After that, the reaction is terminated with an ethanol solution containing 1wt% of antioxidant 1076 to obtain a terminated polymer solution. The polymer solution is eluted in an aqueous medium with a pH value of 7.5 (the volume ratio of the polymer solution to the aqueous medium is 50:100), and then the eluted product is washed with water and dried. The polybutadiene product S1 is obtained with a yield of 87.6%.

[0084] The conditions for elution treatment are: temperature 70°C, time 120 min;

[0085] The drying conditions are as follows: temperature 40°C, time 4h.

[0086] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 1 calculated as silicon, and the butadiene monomer is 1.20×10 -4 :1.35×10 -3 :1.20×10 -3 :4.50×10 -3 :1.

[0087] In the prepared polybutadiene product S1, the weight average molecular weight (M w ) is 201kg / mol, and the molecular weight distribution index (M w / M n ) is 1.6, and the molar content of the cis structure is 97.3%.

[0088] Example 2

[0089] This embodiment provides a method for preparing a polybutadiene elastomer, the method comprising:

[0090] Prepare a butadiene-n-hexane solution with a butadiene concentration of 3.26 mol / L for later use;

[0091] Under nitrogen protection, firstly, the nickel carboxylate and the organoaluminum compound I are mixed to obtain a mixed solution I;

[0092] The mixed solution I was mixed with 1000 mL of the aforementioned butadiene-n-hexane solution (butadiene concentration was 3.26 mol / L) to obtain a mixed solution II;

[0093] The boron trifluoride complex II was mixed with 6.25 mmol of the silicon-containing compound 1 (the molar ratio of the silicon-containing compound 1 to butadiene was 0.002:1) to obtain a mixed solution III;

[0094] The mixed solution II was contacted with the mixed solution III to carry out polymerization reaction at 50° C. for 5 hours. The post-treatment method, elution treatment and drying treatment conditions were the same as those in Example 1, except that the pH value of the aqueous medium was 9.0. The polybutadiene product S2 was obtained with a yield of 74.0%.

[0095] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex II calculated as boron, the silicon-containing compound 1 calculated as silicon, and the butadiene monomer is 1.00×10 -4:5.00×10 -4 :8.00×10 -4 :2.00×10 -3 :1.

[0096] In the prepared polybutadiene product S2, the weight average molecular weight of the polybutadiene was 314 kg / mol, the molecular weight distribution index was 2.1, and the molar content of the cis structure was 97.9%.

[0097] Example 3

[0098] The polybutadiene elastomer was prepared according to the method of Example 1, except that the amount of the silicon-containing compound 1 used was 9.78 mmol, that is, the molar ratio of the silicon-containing compound 1 to butadiene was 3.00×10 -3 :1.

[0099] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 1 calculated as silicon, and the butadiene monomer is 1.00×10 -4 :1.13×10 -3 :1.00×10 -3 :3.00×10 -3 :1.

[0100] The other steps were the same as those in Example 1, and polybutadiene product S3 was obtained with a yield of 79.4%.

[0101] In the polybutadiene product S3, the weight average molecular weight of polybutadiene is 318 kg / mol, the molecular weight distribution index is 2.0, and the molar content of the cis structure is 97.8%.

[0102] Example 4

[0103] The polybutadiene elastomer was prepared according to the method of Example 1, except that the molar ratio of the nickel carboxylate I to the butadiene monomer was 1.5×10 -4 : 1, the amount of silicon-containing compound 1 used is 4.89 mmol, that is, the molar ratio of the silicon-containing compound 1 to the butadiene monomer is 1.5×10 -3 :1.

[0104] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 1 calculated as silicon, and the butadiene monomer is 1.50×10 -4 :1.69×10 -3 :1.50×10 -3 :1.50×10-3 :1.

[0105] The other steps were the same as those in Example 1, and polybutadiene S4 was obtained with a yield of 81.6%.

[0106] In the polybutadiene product S4, the weight average molecular weight of polybutadiene is 255 kg / mol, the molecular weight distribution index is 2.1, and the molar content of the cis structure is 96.9%.

[0107] Example 5

[0108] The polybutadiene elastomer was prepared according to the method of Example 1, except that the amount of the silicon-containing compound 1 used was 19.56 mmol, that is, the molar ratio of the silicon-containing compound 1 to butadiene was 6.0×10 -3 :1.

[0109] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 1 calculated as silicon, and the butadiene monomer is 1.00×10 -4 :1.13×10 -3 :1.00×10 -3 :6.00×10 -3 :1.

[0110] The other steps were the same as those in Example 1, and polybutadiene product S5 was obtained with a yield of 82.7%.

[0111] In the polybutadiene product S5, the weight average molecular weight of polybutadiene is 317 kg / mol, the molecular weight distribution index is 2.4, and the molar content of the cis structure is 98.1%.

[0112] Example 6

[0113] The polybutadiene elastomer was prepared according to the method of Example 1, except that the molar ratio of the nickel carboxylate to the butadiene monomer was 2.0×10 -4 , 14.67 mmol of silicon-containing compound 1 was replaced by 22.8 mmol of silicon-containing compound 2, that is, the molar ratio of silicon-containing compound 2 to butadiene monomer was 7.0×10 -3 :1.

[0114] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 2 calculated as silicon, and the butadiene monomer is 2.00×10 -4 :2.25×10 -3 :2.00×10-3 :7.00×10 -3 :1.

[0115] The other steps were the same as those in Example 1, and polybutadiene product S6 was obtained with a yield of 52.2%.

[0116] In the polybutadiene product S6, the weight average molecular weight of polybutadiene is 254 kg / mol, the molecular weight distribution index is 1.8, and the molar content of the cis structure is 96.7 mol%.

[0117] Example 7

[0118] A polybutadiene elastomer was prepared according to the method of Example 1, except that the silicon-containing compound 1 was directly mixed with the butadiene-n-hexane solution;

[0119] The amount of silicon-containing compound 1 is 9.78 mmol, that is, the molar ratio of silicon-containing compound 1 to butadiene is 3.0×10 -3 :1.

[0120] The boron trifluoride complex used is boron trifluoride complex III.

[0121] In the polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex III calculated as boron, the silicon-containing compound 1 calculated as silicon to the butadiene monomer is 1.00×10 -4 :1.25×10 -3 :1.00×10 -3 :3.00×10 -3 :1.

[0122] The other steps were the same as those in Example 1, and polybutadiene product S7 was obtained with a yield of 33.1%.

[0123] In the polybutadiene product S7, the weight average molecular weight of the polybutadiene product is 342 kg / mol, the molecular weight distribution index is 1.6, and the molar content of the cis structure is 97.1%.

[0124] Example 8

[0125] The polybutadiene elastomer was prepared according to the method of Example 4, except that after the polymerization reaction was completed and before the elution treatment, the silicon-containing compound 3 was added to the polymer solution so that the molar ratio of the silicon-containing compound 3 to the butadiene in terms of silicon element was 9.0×10 -3 :1.

[0126] In the above polymerization system, the molar ratio of the nickel carboxylate calculated as nickel, the organoaluminum compound I calculated as aluminum, the boron trifluoride complex I calculated as boron, the silicon-containing compound 3 calculated as silicon, and the butadiene monomer is 2.00×10 -4 :2.25×10 -3 :2.00×10 -3 :9.00×10 -3 :1.

[0127] The other steps were the same as those in Example 1, and polybutadiene product S8 was obtained with a yield of 84.0%.

[0128] In the polybutadiene product S8, the viscosity-average molecular weight of polybutadiene is 208 kg / mol, and the molar content of the cis structure is 96.5%.

[0129] Comparative Example 1

[0130] A polybutadiene elastomer was prepared according to the method of Example 1, except that the silicon-containing compound 1 was not added;

[0131] The other steps are the same as those in Example 1 to obtain polybutadiene DS1 with a yield of 85.3%;

[0132] The usage ratio of each component in the catalyst is the same as that in Example 1.

[0133] In the polybutadiene product DS1, the weight average molecular weight of polybutadiene is 285 kg / mol, the molecular weight distribution index is 2.6, and the molar content of the cis structure is 96.2%.

[0134] Comparative Example 2

[0135] A polybutadiene elastomer was prepared according to the method of Example 7, except that the silicon-containing compound 1 was not added.

[0136] The other steps were the same as those in Example 7 to obtain a polybutadiene product DS2 with a yield of 85.4%.

[0137] In the polybutadiene product DS2, the weight average molecular weight of polybutadiene is 336 kg / mol, the molecular weight distribution index is 1.6, and the molar content of the cis structure is 95.8%.

[0138] Test Example 1

[0139] The raw rubber of the polybutadiene elastomer of the embodiment and the comparative example was tested for performance, and the specific test results are shown in Table 1.

[0140] Among them, the electronic universal material testing machine of Shimadzu AG-ZS model produced by Japan's Shimadzu Corporation was used to test the tensile strength, Young's modulus and 300% elongation stress of the raw rubber.

[0141] The test method for the cold flow of raw rubber is as follows: cut the raw rubber into cubes of 1cm×1cm×1cm, place them upright on a glass plate in a light-proof condition, leave them at room temperature for 960 hours, record the changes in the height dimensions of the samples, and calculate the height retention rate of the raw rubber.

[0142] The calculation formula of the height retention rate at room temperature is: (sample height after 960 hours of placement / sample height before placement)×100%.

[0143] Table 1

[0144]

[0145] It can be seen from the results in the above table that the polybutadiene elastomer obtained by the one-step polymerization of butadiene and a silicon-containing compound in a specific ratio under the action of a catalyst in the present invention can have excellent raw rubber cold flow performance and raw rubber strength while ensuring mechanical properties.

[0146] By comparing Example 1 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 3.2 times, the Young's modulus is increased by 17.9 times, the 300% elongation stress is increased by 1.4 times, and the height retention rate at room temperature is increased by 73%.

[0147] By comparing Example 2 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 3.1 times, the Young's modulus is increased by 6.8 times, the 300% elongation stress is increased by 1.2 times, and the height retention rate at room temperature is increased by 71%.

[0148] By comparing Example 3 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 4.9 times, the Young's modulus is increased by 6.4 times, the 300% elongation stress is increased by 1.8 times, and the height retention rate at room temperature is increased by 73%.

[0149] By comparing Example 4 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 1.7 times, the Young's modulus is increased by 5.2 times, the 300% elongation stress is increased by 1.9 times, and the height retention rate at room temperature is increased by 60%.

[0150] By comparing Example 5 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 2.1 times, the Young's modulus is increased by 6.0 times, the 300% elongation stress is increased by 0.8 times, and the height retention rate at room temperature is increased by 72%.

[0151] By comparing Example 6 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 1.9 times, the Young's modulus is increased by 5.9 times, the 300% elongation stress is increased by 1.9 times, and the height retention rate at room temperature is increased by 69%.

[0152] By comparing Example 7 with Comparative Example 2, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 0.6 times, the Young's modulus is increased by 5.0 times, the 300% elongation stress is increased by 30%, and the height retention rate at room temperature is increased by 61%.

[0153] By comparing Example 8 with Comparative Example 1, the raw rubber strength of the polybutadiene elastomer prepared by the method of the present invention is increased by 4.3 times, the Young's modulus is increased by 8.4 times, the 300% elongation stress is increased by 1.5 times, and the height retention rate at room temperature is increased by 72%.

[0154] 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 polybutadiene elastomer, characterized in that: The molar content of the cis structure of the polybutadiene elastomer is not less than 95%, the weight average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol, or the viscosity average molecular weight of the polybutadiene elastomer is not less than 100 kg / mol; the raw rubber strength of the polybutadiene elastomer is not less than 130 kPa, and the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960 hours is not less than 75%.

2. The polybutadiene elastomer according to claim 1, wherein In the polybutadiene elastomer, the molar content of the cis structure is not less than 96%.

3. The polybutadiene elastomer according to claim 1 or 2, wherein The weight average molecular weight of the polybutadiene elastomer is not less than 150 kg / mol, preferably not less than 200 kg / mol; or The viscosity average molecular weight of the polybutadiene elastomer is not less than 150 kg / mol, preferably not less than 200 kg / mol.

4. The polybutadiene elastomer according to any one of claims 1 to 3, wherein The green strength of the polybutadiene elastomer is not less than 150 kPa, preferably not less than 170 kPa; Preferably, the height retention rate of the raw rubber of the polybutadiene elastomer after being placed at room temperature for 960 hours is not less than 80%.

5. A method for preparing the polybutadiene elastomer according to any one of claims 1 to 4, characterized in that: The method comprises: subjecting butadiene monomer to polymerization reaction in the presence of a catalyst and a silicon-containing compound; The silicon-containing compound is a vinyl silane compound and / or nano silicon dioxide, and the molar ratio of the silicon-containing compound to the butadiene monomer is 0.0001-0.05:

1.

6. The method according to claim 5, wherein: The molar ratio of the silicon-containing compound to the butadiene monomer is 0.0008-0.04:1, preferably 0.001-0.03:

1.

7. The method according to claim 5 or 6, wherein: The vinyl silane-containing compound is selected from at least one of dimethyl (4-vinylphenyl) silane, trimethyl (4-vinylphenyl) silane, vinyl triphenyl silane, vinyl dimethyl chlorosilane, vinyl methyl dichlorosilane, vinyl dimethyl ethoxy silane, vinyl dimethoxymethyl silane, vinyl trimethoxy silane, trimethoxy (4-vinylphenyl) silane, vinyl methyl diethoxy silane, vinyl triethoxy silane, vinyl triisopropoxy silane, vinyl tri-tert-butoxy silane, vinyl tris (dimethylsiloxy) silane, vinyl tris (trimethylsiloxy) silane, vinyl tris (2-methoxyethoxy) silane, vinyl methyl bis (trimethylsiloxy) silane and vinyl tributanoximo silane.

8. The method according to any one of claims 5 to 7, wherein: The polymerization reaction conditions at least include: a reaction temperature of -20°C to 120°C, and a reaction time of 0.5h to 30h; Preferably, the polymerization reaction conditions at least include: a reaction temperature of 10°C to 110°C, a reaction time of 1h to 20h; Preferably, the polymerization reaction conditions at least include: a reaction temperature of 20° C. to 100° C., and a reaction time of 1.5 h to 15 h.

9. The method according to any one of claims 5 to 8, wherein: The method further comprises: eluting the polymer solution obtained by the polymerization reaction in an aqueous medium with a pH value of 5.5-10.0, and drying the eluted product after washing with water; Preferably, the ratio of the polymer solution to the aqueous medium is 1-100:100, preferably 2-80:100, more preferably 5-60:100; Preferably, the conditions of the elution treatment at least include: a temperature of 20°C to 100°C, preferably 30°C to 100°C; and a time of 1 min to 600 min, preferably 5 min to 600 min.

10. Use of the polybutadiene elastomer according to any one of claims 1 to 4 in tires, plastic modification, conveyor belts, hoses, shoe soles, seals or golf ball cores.

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