Monovinylarene-conjugated diene polymer as well as preparation method and application thereof

Abstract

The invention relates to the field of polymers, and discloses a monovinylarene-conjugated diene polymer as well as a preparation method and application thereof. The polymer contains a structure formed by coupling a monovinylarene-conjugated diene polymer chain R1, a monovinylarene-conjugated diene polymer chain R2 and a polymer chain R1-polymer chain R2, the number-average molecular weight of R1 is 7000-17000 g / mol, the number-average molecular weight of R2 is 4000-12000 g / mol, and by taking the mass of a conjugated diene structural unit in R1 as a reference, the number-average molecular weight of R2 is 1-20 g / mol. The content of a conjugated diene side group structure is 10-30% by taking the mass of the conjugated diene structure unit in R2 as a reference, and the content of the conjugated diene side group is 50-65% by taking the mass of the conjugated diene structure unit in R2 as a reference. The monovinylarene-conjugated diene polymer disclosed by the invention is added into a rubber matrix as rubber operation oil, so that a composite material can be endowed with excellent wear resistance, relatively high wet skid resistance and relatively low rolling resistance.

Description

Technical Field

[0001] The present invention relates to the field of polymers, and in particular, to a mono-vinyl aromatic-conjugated diene polymer, a preparation method thereof, and an application thereof. Background Art

[0002] Solution-polymerized styrene-butadiene rubber (SSBR, also known as solution-polymerized styrene-butadiene rubber) is a copolymer rubber prepared by anionic solution polymerization of butadiene and styrene monomers with an alkyl lithium initiator in a hydrocarbon solvent.

[0003] Since SSBR has excellent abrasion resistance, resistance to groove cracking, good grip on wet roads, heat resistance, and flex resistance after long-term exposure at high temperatures, and also has the characteristics of low heat generation during mixing in a Banbury mixer, small extrusion expansion ratio, and high filling amount, the proportion applied in tire products is increasing.

[0004] Utilizing the abrasion resistance, excellent dynamic performance, and low-temperature characteristics of SSBR, etc., it can also be used to manufacture large tires, snow tires, etc.

[0005] From the perspectives of abrasion resistance, tensile strength, cure flatness, flex resistance, and heat resistance, etc., SSBR is suitable for manufacturing conveyor belts, especially heat-resistant conveyor belts.

[0006] SSBR also has advantages such as good electrical insulation performance, excellent color, low ash content, and low content of non-rubber components.

[0007] From the perspective of the balance between processing performance and physical and mechanical properties, SSBR is a rubber variety with a variety of comprehensive properties.

[0008] In view of the excellent properties of solution-polymerized styrene-butadiene rubber, there are many studies in this field. In CN102344529A, a method of adding an anionic initiator dropwise multiple times and coupling multiple times is used to prepare solution-polymerized styrene-butadiene rubber. This method can improve the distribution coefficient of the polymer, which is beneficial to processing performance, but there is no innovative change in the microstructure, and the process of this method is relatively complex, the operation is inconvenient, and the test repeatability is not good. CN1432586A discloses a solution-polymerized styrene-butadiene rubber containing a high molecular weight, but the content of the high molecular weight part is 10-40% by weight, and the content is too high, which is not conducive to the processing of later products.

[0009] As is known to all, in the process of preparing rubber products, processing oil needs to be added to improve the processing performance of the rubber compound and reduce the cost. In the field of tires, with the introduction of the concept of "green tires", the formula design is varied. Because the filling system of green tires is mainly white carbon black, white carbon black is a strong polar substance and is difficult to disperse in the rubber matrix. Therefore, it is necessary to add dispersants such as polyethylene glycol to solve the dispersion problem of white carbon black. In summary, both processing oil and dispersants need to be introduced into the green tire formula, and there are many types of fillers added. The processing oil currently used is non-polar substances such as aromatic oil and cycloalkane oil, and the molecular weight is low. It is easy to migrate to the surface of the product during the storage of the finished tire, causing the product to change color and produce quality fluctuations. There are also studies on using liquid rubber instead of processing oil. The liquid rubber used is still non-polar and cannot help white carbon black to be evenly dispersed in the rubber. CN101792545B introduces an isoprene liquid rubber for the purpose of reducing the high wet skid resistance of rubber, but this liquid rubber is only suitable for carbon black systems and has no obvious effect in white carbon black systems. In order to solve the above problems and obtain a tire with fuel economy. Summary of the invention

[0010] The object of the present invention is to provide a structurally diversified monovinyl aromatic hydrocarbon-conjugated diene polymer and a preparation method and application thereof.

[0011] The monovinyl aromatic hydrocarbon-conjugated diene polymer of the present invention achieves the coexistence of two structures with different benzene amounts and different side group contents in the polymer through an ingeniously designed structure. When added to a rubber matrix as a rubber processing oil, the composite material is endowed with excellent wear resistance, high anti-wet skid resistance and low rolling resistance. It is a better choice of green tire tread rubber processing operating oil with white carbon black as a main reinforcing agent, so that the tire product has excellent fuel economy, wet grip performance and wear resistance.

[0012] To achieve the above object, on the one hand, the present invention provides a vinylarene-conjugated diene polymer, wherein the polymer contains a vinylarene-conjugated diene polymerization chain R1, a vinylarene-conjugated diene polymerization chain R2, and a structure formed by coupling the vinylarene-conjugated diene polymerization chain R1 and the vinylarene-conjugated diene polymerization chain R2. The number-average molecular weight of the vinylarene-conjugated diene polymerization chain R1 is 7000-17000 g / mol, and the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R2 is 4000-12000 g / mol. Based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R1, the content of the conjugated diene side group structure in the vinylarene-conjugated diene polymerization chain R1 is 10-30%. Based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R2, the content of the conjugated diene side group in the vinylarene-conjugated diene polymerization chain R2 is 50-65%.

[0013] Preferably, based on the mass of the vinylarene-conjugated diene polymerization chain R1, the mass content of the vinylarene structural unit in the vinylarene-conjugated diene polymerization chain R1 is 25-45%, preferably 30-40%.

[0014] Preferably, based on the mass of the vinylarene-conjugated diene polymer, the mass content of the vinylarene-conjugated diene polymerization chain R1 is 10-25%, and the mass content of the vinylarene-conjugated diene polymerization chain R2 is 75-90%.

[0015] Preferably, the vinylarene is selected from one or more of styrene, vinyltoluene, α-methylstyrene, 4-tert-butylstyrene, 4-methylstyrene, 3,5-diethylstyrene, 3,5-din-butylstyrene, 4-n-propylstyrene, and 4-dodecylstyrene; more preferably, the vinylarene is styrene.

[0016] Preferably, based on the mass of the vinylarene-conjugated diene polymerization chain R2, the mass content of the vinylarene in the vinylarene-conjugated diene polymerization chain R2 is 5-25%, preferably 10-20%.

[0017] Preferably, the coupling efficiency is 40-80% by weight, preferably 50-65% by weight.

[0018] Preferably, the coupling structural unit is selected from one or more of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane, and dichlorosilane, preferably from silicon tetrachloride.

[0019] Preferably, the conjugated diene is selected from one or more of butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, and 2,3-dimethylbutadiene; more preferably, the conjugated diene is butadiene.

[0020] According to a second aspect of the present invention, there is provided a method for preparing a monovinyl aromatic-conjugated diene polymer, wherein the method comprises the following steps:

[0021] 1) A step of subjecting a material A containing a monovinyl aromatic monomer, a conjugated diene monomer, and a nonpolar solvent to a first polymerization reaction in the presence of an anionic initiator a;

[0022] 2) A step of subjecting the first polymerization reaction product obtained in step 1) to a second polymerization reaction with a material B containing a monovinyl aromatic monomer, a conjugated diene monomer, a polar regulator, and a nonpolar solvent in the presence of an anionic initiator b;

[0023] 3) A step of subjecting the second polymerization product obtained in step 2) to a coupling reaction in the presence of a coupling agent.

[0024] Preferably, the material A further contains a polar regulator, and the amount of the polar regulator in the material A is 0-50 ppm, preferably 10-40 ppm.

[0025] Preferably, the amount of the polar regulator in the material B is 100-600 ppm, preferably 200-400 ppm.

[0026] Preferably, based on the total mass of the polymerization monomers, the mass content of the polymerization monomers in the material A is 10-25%, and the mass content of the polymerization monomers in the material B is 75-90%.

[0027] Preferably, the molar ratio of the anionic initiator a to the anionic initiator b is 1:1.4-26.

[0028] Preferably, the monovinyl aromatic is selected from one or more of styrene, vinyltoluene, α-methylstyrene, 4-tert-butylstyrene, 4-methylstyrene, 3,5-diethylstyrene, 3,5-di-n-butylstyrene, 4-n-propylstyrene, and 4-dodecylstyrene; more preferably, the monovinyl aromatic is styrene.

[0029] Preferably, the mass percentage content of the monovinyl aromatic monomer in the material A is 25-45%, preferably 30-40%;

[0030] Preferably, the mass percentage content of the monovinyl aromatic monomer in the material B is 25-45%, preferably 30-40%.

[0031] Preferably, the conjugated diene is selected from one or more of butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, and 2,3-dimethylbutadiene; more preferably, the conjugated diene is butadiene.

[0032] Preferably, the anionic initiator a and the anionic initiator b are each independently a compound having an RLi structure, where R is a straight-chain or branched-chain alkyl group having 1 to C 10 of.

[0033] Preferably, R is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl.

[0034] Preferably, the coupling agent is one or more of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane, and dichlorosilane, preferably silicon tetrachloride.

[0035] Preferably, the polar regulator is selected from one or more of diethyl ether, dibutyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofurfuryl ether, dioxane, crown ether, triethylamine, tetramethylethylenediamine, hexamethylphosphoramide, potassium tert-butoxide, potassium tert-pentoxide, potassium laurate, potassium alkylbenzenesulfonate, and sodium alkylbenzenesulfonate, preferably tetrahydrofurfuryl ether.

[0036] According to the third aspect of the present invention, there is provided a mono-vinyl aromatic-conjugated diene polymer prepared by the method described in the second aspect of the present invention.

[0037] According to the fourth aspect of the present invention, there is provided the use of the mono-vinyl aromatic-conjugated diene polymer described in the first and third aspects of the present invention as an operating oil in a rubber compound for a tire tread.

[0038] Through the above technical solutions, the present invention can provide a mono-vinyl aromatic-conjugated diene polymer with a diversified structure, and its preparation method and application. The mono-vinyl aromatic-conjugated diene polymer of the present invention, through a clever structural design, realizes the coexistence of two structures with different benzene contents and different side group contents in the polymer. When it is added to a rubber matrix as a rubber processing oil, it endows the composite material with excellent wear resistance, high wet skid resistance, and low rolling resistance. It is a preferred choice for a green tire tread rubber processing oil with silica as the main reinforcing agent, making the tire product have excellent fuel economy, wet grip performance, and wear resistance. Detailed Embodiments

[0039] The endpoints and any values disclosed in this text for a range are not limited to the exact range or value. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the values between the endpoints of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this text.

[0040] In the present invention, the term "monovinylarene" refers to a compound formed by substituting one hydrogen on the aromatic ring with a vinyl group. For example, the monovinylarene can be one or more selected from the compounds shown in Formula II.

[0041]

[0042] In Formula II, R1 is a substituted or unsubstituted aryl group having 6 to C 20 Specific examples of the substituted or unsubstituted aryl group having 6 to C 20 can include, but are not limited to: phenyl, o-tolyl, m-tolyl, p-tolyl, o-ethylphenyl, m-ethylphenyl, p-ethylphenyl, o-tert-butylphenyl, m-tert-butylphenyl, p-tert-butylphenyl, p-dodecylphenyl, 3,5-diethylphenyl, 2,4-di-n-butylphenyl, 3,5-di-n-butylphenyl, p-n-propylphenyl, and 2,4-diethylphenyl.

[0043] Preferably, the monovinylarene is one or more selected from styrene, vinyltoluene, α-methylstyrene, 4-tert-butylstyrene, 4-methylstyrene, 3,5-diethylstyrene, 3,5-di-n-butylstyrene, 4-n-propylstyrene, and 4-dodecylstyrene.

[0044] More preferably, the monovinylarene is one or more selected from styrene, 2-methylstyrene, and 4-methylstyrene.

[0045] Even more preferably, the monovinylarene is styrene.

[0046] In the present invention, the term "conjugated diene" refers to an unsaturated hydrocarbon containing conjugated double bonds (i.e., -C=C-C=C-) in its molecular structure, and can be various conjugated dienes commonly used in the art without particular limitation. For example: the conjugated diene is one or more selected from conjugated dienes having 4 to 8 carbon atoms.

[0047] Preferably, the conjugated diene is one or more selected from butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, and 2,3-dimethylbutadiene.

[0048] More preferably, the conjugated diene is butadiene and / or isoprene.

[0049] More preferably, the conjugated diene is butadiene.

[0050] In the present invention, the "coupling efficiency" refers to the weight percentage of the number of molecular chains to be coupled in the total number of molecular chains, that is, the coupling efficiency refers to the content of the polymer formed by coupling (i.e., the coupling component) based on the total amount of the monovinyl aromatic-conjugated diene polymer, and the balance is the content of the uncoupled monovinyl aromatic-conjugated diene polymer (i.e., the uncoupled component).

[0051] In the present invention, the monovinyl aromatic-conjugated diene polymer chain R1 includes the "monovinyl aromatic-conjugated diene polymer chain R1" and the "monovinyl aromatic-conjugated diene polymer chain R1" in the "monovinyl aromatic-conjugated diene polymer chain R1 - monovinyl aromatic-conjugated diene polymer chain R2".

[0052] In the present invention, the monovinyl aromatic-conjugated diene polymer chain R2 includes the "monovinyl aromatic-conjugated diene polymer chain R2" and the "monovinyl aromatic-conjugated diene polymer chain R2" in the "monovinyl aromatic-conjugated diene polymer chain R1 - monovinyl aromatic-conjugated diene polymer chain R2".

[0053] According to the first aspect of the present invention, there is provided a monovinyl aromatic-conjugated diene polymer, wherein the polymer contains a structure formed by coupling the monovinyl aromatic-conjugated diene polymer chain R1, the monovinyl aromatic-conjugated diene polymer chain R2, and the monovinyl aromatic-conjugated diene polymer chain R1 - monovinyl aromatic-conjugated diene polymer chain R2. Among them, the number-average molecular weight of the monovinyl aromatic-conjugated diene polymer chain R1 is 7000 - 17000 g / mol, the number-average molecular weight of the monovinyl aromatic-conjugated diene polymer chain R2 is 4000 - 12000 g / mol. Based on the mass of the conjugated diene structural unit in the monovinyl aromatic-conjugated diene polymer chain R1, the content of the conjugated diene side group structure in the monovinyl aromatic-conjugated diene polymer chain R1 is 10 - 30%, and based on the mass of the conjugated diene structural unit in the monovinyl aromatic-conjugated diene polymer chain R2, the content of the conjugated diene side group in the monovinyl aromatic-conjugated diene polymer chain R2 is 50 - 65%.

[0054] According to the present invention, the vinylarene-conjugated diene polymer contains a vinylarene-conjugated diene polymerization chain R1, a vinylarene-conjugated diene polymerization chain R2, and a structure formed by coupling the vinylarene-conjugated diene polymerization chain R1 and the vinylarene-conjugated diene polymerization chain R2; preferably, the vinylarene-conjugated diene polymer is a structure formed by coupling the vinylarene-conjugated diene polymerization chain R1, the vinylarene-conjugated diene polymerization chain R2, and the vinylarene-conjugated diene polymerization chain R1-vinylarene-conjugated diene polymerization chain R2.

[0055] According to the present invention, the vinylarene-conjugated diene polymerization chain R1 is a polymer chain formed by copolymerizing a vinylarene and a conjugated diene in the presence of the following anionic initiator a.

[0056] In the present invention, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R1 is 7000-17000 g / mol; preferably, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R1 is 8000-15500 g / mol; more preferably, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R1 is 8000-15000 g / mol.

[0057] In the present invention, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R2 is 4000-12000 g / mol; preferably, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R2 is 4500-11000 g / mol; more preferably, the number-average molecular weight of the vinylarene-conjugated diene polymerization chain R2 is 5000-10000 g / mol.

[0058] In the present invention, based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R1, the content of the conjugated diene side group structure in the vinylarene-conjugated diene polymerization chain R1 is 10-30%; preferably, based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R1, the content of the conjugated diene side group structure in the vinylarene-conjugated diene polymerization chain R1 is 15-30%.

[0059] In the present invention, based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R2, the content of the conjugated diene side group in the vinylarene-conjugated diene polymerization chain R2 is 50-65%; preferably, based on the mass of the conjugated diene structural unit in the vinylarene-conjugated diene polymerization chain R2, the content of the conjugated diene side group in the vinylarene-conjugated diene polymerization chain R2 is 50-60%.

[0060] According to the present invention, preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer, the mass content of the mono-vinyl aromatic-conjugated diene polymer chain R1 is 10-25%, and the mass content of the mono-vinyl aromatic-conjugated diene polymer chain R2 is 75-90%.

[0061] Specific examples of the mass content of the mono-vinyl aromatic-conjugated diene polymer chain R1 based on the mass of the mono-vinyl aromatic-conjugated diene polymer, for example, can include: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc., and the ranges formed by any two of the above.

[0062] Specific examples of the mass content of the mono-vinyl aromatic-conjugated diene polymer chain R2 based on the mass of the mono-vinyl aromatic-conjugated diene polymer, for example, can include: 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, etc., and the ranges formed by any two of the above.

[0063] According to the present invention, preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R1, the mass content of the mono-vinyl aromatic structural unit in the mono-vinyl aromatic-conjugated diene polymer chain R1 is 25-45%; more preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R1, the mass content of the mono-vinyl aromatic structural unit in the mono-vinyl aromatic-conjugated diene polymer chain R1 is 30-40%.

[0064] According to the present invention, preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R1, the mass content of the conjugated diene structural unit in the mono-vinyl aromatic-conjugated diene polymer chain R1 is 55-75%; more preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R1, the mass content of the conjugated diene structural unit in the mono-vinyl aromatic-conjugated diene polymer chain R1 is 60-70%.

[0065] According to the present invention, preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R2, the mass content of the mono-vinyl aromatic in the mono-vinyl aromatic-conjugated diene polymer chain R2 is 5-25%; more preferably, based on the mass of the mono-vinyl aromatic-conjugated diene polymer chain R2, the mass content of the mono-vinyl aromatic in the mono-vinyl aromatic-conjugated diene polymer chain R2 is 10-20%.

[0066] In the present invention, the coupling is carried out by means of a coupling agent, and the coupling unit derived from the coupling agent is selected from silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane or dichlorosilane, preferably silicon tetrachloride.

[0067] Preferably, the efficiency of the coupling is 40 - 80% by weight; more preferably, the efficiency of the coupling is 50 - 65% by weight.

[0068] The mono-vinyl aromatic-conjugated diene polymer of the present invention, through a clever structural design, realizes the coexistence of two structures with different benzene contents and different side group contents in the polymer. When it is added to a rubber matrix as a rubber processing oil, it endows the composite material with excellent wear resistance, relatively high wet skid resistance and low rolling resistance. It is a preferred choice for the processing operation oil of green tire tread rubber with silica as the main reinforcing agent, enabling tire products to have excellent fuel economy, wet grip performance and wear resistance.

[0069] According to the second aspect of the present invention, there is provided a method for preparing a mono-vinyl aromatic-conjugated diene polymer, which method comprises the following steps:

[0070] 1) A step of carrying out a first polymerization reaction on a material A containing a mono-vinyl aromatic monomer, a conjugated diene monomer and a non-polar solvent in the presence of an anionic initiator a;

[0071] 2) A step of carrying out a second polymerization reaction on the first polymerization product obtained in step 1) with a material B containing a mono-vinyl aromatic monomer, a conjugated diene monomer, a polar regulator and a non-polar solvent in the presence of an anionic initiator b;

[0072] 3) A step of carrying out a coupling reaction on the second polymerization product obtained in step 2) in the presence of a coupling agent.

[0073] According to the present invention, preferably, based on the total mass of the polymerization monomers, the mass content of the polymerization monomers in the material A is 10 - 25%, and the mass content of the polymerization monomers in the material B is 75 - 90%.

[0074] Specific examples of the mass content of the polymerization monomers in the material A, based on the total mass of the polymerization monomers, can be, for example: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc., and ranges formed by any two of the above.

[0075] Specific examples of the mass content of the polymerizable monomer in the material B based on the total mass of all polymerizable monomers include, for example: 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, etc., and ranges formed by any two of the above.

[0076] According to the present invention, preferably, the material A further contains a polarity regulator, and the amount of the polarity regulator in the material A is 50 ppm or less; more preferably, the amount of the polarity regulator in the material A is 10 - 40 ppm.

[0077] According to the present invention, preferably, the amount of the polarity regulator in the material B is 100 - 600 ppm; more preferably, the amount of the polarity regulator in the material B is 200 - 400 ppm.

[0078] The polarity regulator can be a substance that can regulate the microstructure of the molecular chain and is commonly used in anionic polymerization systems. Specifically, examples of the polarity regulator include, but are not limited to: one or more of diethyl ether, dibutyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofurfuryl ethyl ether, dioxane, crown ether, triethylamine, tetramethylethylenediamine, hexamethylphosphoric triamide, potassium tert-butoxide, potassium tert-amylate, potassium laurate, potassium alkylbenzenesulfonate, and sodium alkylbenzenesulfonate, and preferably tetrahydrofurfuryl ethyl ether.

[0079] According to the present invention, the material A is formed by dissolving a monovinyl aromatic monomer, a conjugated diene monomer, and optionally a polarity regulator in a nonpolar solvent. In addition, the material B is also formed by dissolving a monovinyl aromatic monomer, a conjugated diene monomer, and a polarity regulator in a nonpolar solvent.

[0080] Preferably, the mass percentage of the monovinyl aromatic monomer in the material A is 25 - 45%; more preferably, the mass percentage of the monovinyl aromatic monomer in the material A is 30 - 40%.

[0081] Preferably, the mass percentage of the conjugated diene monomer in the material A is 55 - 75%; more preferably, the mass percentage of the conjugated diene monomer in the material A is 60 - 70%.

[0082] Preferably, the mass percentage of the monovinyl aromatic monomer in the material B is 5 - 25%; more preferably, the mass percentage of the monovinyl aromatic monomer in the material B is 10 - 20%.

[0083] Preferably, the mass percentage content of the conjugated diene monomer in the material B is 75-95%; more preferably, the mass percentage content of the conjugated diene monomer in the material B is 80-90%.

[0084] According to the present invention, the non-polar solvent is a hydrocarbon solvent and / or an ether solvent. The hydrocarbon solvent can be one or more of C3-C10 cycloalkanes, aromatic hydrocarbons and straight-chain alkanes. Specific examples of the hydrocarbon solvent can include, but are not limited to: one or more of benzene, toluene, xylene, ethylbenzene, propane, butane, n-pentane, cyclopentane, methylcyclopentane, n-heptane, cycloheptane, n-hexane, cyclohexane, n-octane, decane and cyclooctane, preferably cyclohexane and n-hexane. The ether solvent can be a C4-C15 monoether and / or polyether. Specific examples of the ether solvent can include, but are not limited to: tert-butoxyethoxyethane and / or tetrahydrofuran. Among them, these solvents can be used alone or in combination.

[0085] According to the present invention, the anionic polymerization initiators a and b can be initiators commonly used in the field of anionic polymerization. In a preferred embodiment of the present invention, the anionic initiators a and b are each independently a compound having an RLi structure, where R is a straight-chain or branched-chain alkyl group with C1-C 10 of the straight-chain or branched-chain alkyl group.

[0086] Preferably, the R is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl and n-decyl.

[0087] Specific examples of the anionic initiator can include, but are not limited to: ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium and n-hexyllithium. Among them, n-butyllithium and / or sec-butyllithium are preferred, and n-butyllithium is more preferred.

[0088] In a preferred embodiment of the present invention, the anionic polymerization initiators a and b are the same.

[0089] The dosage of the anionic polymerization initiator can be selected according to the expected molecular weight of the mono-vinyl aromatic-conjugated diene polymer. The method of determining the dosage of the initiator according to the expected polymer molecular weight is well known to those skilled in the art and will not be elaborated herein.

[0090] In the present invention, the number-average molecular weight and the molecular weight distribution index (Mw / Mn) are determined by gel permeation chromatography using narrow-distribution polystyrene as the standard substance. It should also be noted that in the present invention, the amount of the anionic polymerization initiator refers to the amount of the anionic polymerization initiator added for initiating the polymerization reaction, and does not include the anionic polymerization initiator added before the polymerization reaction for removing impurities in the polymerization system.

[0091] According to the present invention, preferably, the molar ratio of the anionic initiator a to the anionic initiator b is 1:1.4 - 26, for example, it can be: 1:1.5, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, 1:22, 1:24, 1:26, etc., and the ranges formed by any two of the above.

[0092] According to the present invention, preferably, the conditions of the first polymerization reaction include: the temperature is 50 - 100 °C, and the time is 0.2 - 1.5 h; preferably, the conditions of the first polymerization reaction include: the temperature is 60 - 80 °C, and the time is 0.5 - 0.8 h.

[0093] According to the present invention, preferably, the conditions of the second polymerization reaction include: the temperature is 50 - 100 °C, and the time is 0.3 - 1.5 h; preferably, the conditions of the second polymerization reaction include: the temperature is 60 - 80 °C, and the time is 0.6 - 1 h.

[0094] In the present invention, the coupling agent is one or more of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane, and dichlorosilane. Preferably, the coupling agent is one or more of divinylbenzene, silicon tetrachloride, and tin tetrachloride. More preferably, the coupling agent is silicon tetrachloride and / or tin tetrachloride. Further preferably, the coupling agent is tin tetrachloride.

[0095] The amount of the coupling agent can be selected according to the expected coupling efficiency. Generally, the amount of the coupling agent is such that in the coupled monovinyl aromatic-conjugated diene polymer, the content of the coupled polymer is 40 - 80% by weight, preferably 50 - 65% by weight; the content of the uncoupled polymer is 20 - 60% by weight, more preferably 35 - 50% by weight (i.e., the coupling efficiency is 40 - 80% by weight, more preferably 50 - 65% by weight). The polymers before and after coupling can be analyzed by gel permeation chromatography to determine the contents of the coupled polymer and the uncoupled polymer.

[0096] According to the present invention, preferably, the conditions for the coupling reaction include: a temperature of 50 - 100 °C and a time of 0.3 - 1 h; more preferably, the conditions for the coupling reaction include: a temperature of 60 - 80 °C and a time of 0.4 - 0.8 h.

[0097] According to the present invention, preferably, the method further includes a step of contacting the second polymerization product obtained in step 3) with a terminator.

[0098] The terminator can be various substances commonly used in the field of anionic polymerization that can terminate the active chain. For example, it can be water and / or alcohol. When the finally prepared monovinyl aromatic-conjugated diene copolymer is used as a rubber, a tin-containing compound can also be used as the terminator. The tin-containing compound can be trialkyltin chloride, and the alkyl group can be an alkyl group having 1 - 8 carbon atoms. Specific examples of the tin-containing compound can include, but are not limited to: trimethyltin chloride, triethyltin chloride, and tributyltin chloride. The present invention does not particularly limit the amount of the polymerization terminator used, as long as the amount of the terminator is sufficient to deactivate the active centers. In the actual operation process, the amount of the terminator can be determined according to the amount of the anionic polymerization initiator used. Generally, the molar ratio of the terminator to the anionic polymerization initiator can be 0.1 - 1:1.

[0099] According to the present invention, after terminating the polymerization reaction by adding a polymerization terminator, one or more additives can also be added to the obtained mixture according to specific needs to endow the finally prepared monovinyl aromatic-conjugated diene copolymer with new properties and / or improve the properties of the finally prepared monovinyl aromatic-conjugated diene copolymer.

[0100] Specifically, the additive can include an antioxidant. The present invention does not particularly limit the type of the antioxidant, and it can be various conventional antioxidants in the art. For example, the antioxidant can be a phenolic and / or amine antioxidant. Specifically, the antioxidant can be one or more of 4,6-dioctylthiomethyl o-cresol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-p-cresol, tert-butylcatechol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). When pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite are used in combination, the content of tris(2,4-di-tert-butylphenyl) phosphite is preferably not higher than 50% by weight; when octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and tris(2,4-di-tert-butylphenyl) phosphite are used in combination, the content of tris(2,4-di-tert-butylphenyl) phosphite is preferably not higher than 50% by weight.

[0101] According to the present invention, the dosage of the anti-aging agent can be a conventional dosage in the art. For example, based on 100 parts by weight of the polymer, the dosage of the anti-aging agent can be 0.005 - 2 parts by weight, preferably 0.1 - 1 part by weight.

[0102] According to the present invention, the obtained mixture can be purified and separated by conventional methods to obtain the mono-vinyl aromatic hydrocarbon-conjugated diene polymer. Specifically, the obtained mixture can be centrifuged, filtered, decanted or coagulated with hot water to obtain the mono-vinyl aromatic hydrocarbon-conjugated diene copolymer; alternatively, the obtained mixture can be stripped to remove the solvent therein to obtain the mono-vinyl aromatic hydrocarbon-conjugated diene polymer.

[0103] In the third aspect of the present invention, there is provided the mono-vinyl aromatic hydrocarbon-conjugated diene polymer prepared in the second aspect of the present invention.

[0104] According to the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the first aspect of the present invention and the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the third aspect of the present invention, through a clever structural design, two structures with different benzene contents and different side group contents coexist in the polymer. When used as a rubber processing oil and added to a rubber matrix, it endows the composite material with excellent wear resistance, high wet skid resistance and low rolling resistance, and is a preferred choice for the processing operation oil of the green tire tread rubber with silica as the main reinforcing agent, making the tire product have excellent fuel economy, wet grip performance and wear resistance.

[0105] Therefore, in the fourth aspect of the present invention, there is provided the application of the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the first aspect of the present invention and the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the third aspect of the present invention as an operation oil in the rubber for tire treads.

[0106] In the present invention, by using the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the first aspect of the present invention and the mono-vinyl aromatic hydrocarbon-conjugated diene polymer of the third aspect of the present invention as a rubber processing oil and adding it to a rubber matrix, it endows the composite material with excellent wear resistance, high wet skid resistance and low rolling resistance, and is a preferred choice for the processing operation oil of the green tire tread rubber with silica as the main reinforcing agent, making the tire product have excellent fuel economy, wet grip performance and wear resistance.

[0107] The present invention will be described in detail below through examples, but the present invention is not limited to the following examples.

[0108] In the following examples, the microstructure of the polymer was determined by an AVANCE DRX 400MHz nuclear magnetic resonance spectrometer of Bruker Corporation, Switzerland, and the solvent was deuterated chloroform.

[0109] Test conditions for the 1,2-PB content: Bruker AVANCE400 superconducting nuclear magnetic resonance spectrometer (1H-NMR): The resonance frequency of the 1H nucleus is 300.13 MHz, the spectral width is 2747.253 Hz, the pulse width is 5.0 μs, the number of data points is 16K, the sample tube diameter is 5 mm, the solvent is deuterated chloroform CDCl3, the sample concentration is 15% (W / V), the test temperature is room temperature, the number of scans is 16 times, and the chemical shift of tetramethylsilane is calibrated at 0 ppm.

[0110] Since there will be two polymer chains, R1 and R2, in the polymerization kettle simultaneously after the complete reaction of material B, and it is impossible to separately take out R2 for testing, the average mass content of the 1,2-PB structural unit of R1 and R2 is tested, and the 1,2-PB content in R2 is calculated based on the 1,2-PB content in R1 and the average mass content of the 1,2-PB structural unit of R1 and R2.

[0111] The molecular weight and coupling efficiency are determined using an ALLIANCE2690 gel permeation chromatograph (GPC) from Waters Corporation, USA. THF is used as the mobile phase, and narrow distribution polystyrene is used as the standard sample, and the temperature is 25 °C.

[0112] The tensile properties are tested according to the method in the national standard "GB / T 1040-92 Test Method for Tensile Properties of Plastics". The tensile testing machine model is AG-20KNG produced by Shimadzu Corporation; the tensile rate is 500 mm / min, and the test temperature is 23 °C. The effective part length of the specimen is 25 mm, and the width is 6 mm. For each group of specimens, 10 parallel experiments are carried out, and the results are averaged.

[0113] The dynamic mechanical properties are tested on a GABO EPLEXOR-500N dynamic thermomechanical analyzer from Germany to test the viscoelastic behavior of the sample. The sample length is 35 mm, the width is 8 mm, and the thickness is 1.0 mm. The test is carried out in the tensile mode, the test frequency is 11 Hz, the temperature range is -100 to 100 °C, the heating rate is 3 °C / min, the static strain is 1%, and the dynamic strain is 0.25%.

[0114] The DIN abrasion is tested according to the regulations of the national standard "GB / T 9867-2008 Determination of Abrasion Resistance of Vulcanized Rubber (Rotating Drum Type Abrasion Machine Method)". The DIN abrasion machine model is GT-7012-D, a product of Taiwan High Speed Rail Corporation, China.

[0115] Preparation of polymer materials A and B

[0116] Material A1: 10.8 g of styrene, 25.2 g of butadiene, and 0.014 g of tetrahydrofurfuryl ethyl ether are added to 1320 g of a cyclohexane / n-hexane (volume ratio of 15:85) solvent and mixed evenly for standby.

[0117] Material B1: Add 64.8 g of styrene, 259.2 g of butadiene, and 0.6 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0118] Material A2: Add 14.4 g of styrene, 21.6 g of butadiene, and 0.027 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0119] Material B2: Add 32.4 g of styrene, 291.6 g of butadiene, and 0.75 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0120] Material A3: Add 31.6 g of styrene, 58.5 g of butadiene, and 0.035 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0121] Material B3: Add 40.5 g of styrene, 229.5 g of butadiene, and 0.9 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0122] Material A4: Add 27 g of styrene, 63 g of butadiene, and 0.035 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0123] Material B4: Add 54 g of styrene, 216 g of butadiene, and 0.9 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0124] Material A5: Add 25.92 g of styrene, 38.88 g of butadiene, and 0.042 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0125] Material B5: Add 44.28 g of styrene, 250.92 g of butadiene, and 1.05 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0126] Material A6: Add 10.8 g of styrene, 25.2 g of butadiene, and 0.055 g of tetrahydrofurfuryl ethyl ether to 1320 g of cyclohexane / n - hexane (volume ratio 15:85) solvent, mix evenly, and set aside.

[0127] Material B6: 64.8 g of styrene, 259.2 g of butadiene, and 1.2 g of tetrahydrofurfuryl ethyl ether were added to 1320 g of a cyclohexane / n-hexane (volume ratio 15:85) solvent and mixed evenly for standby.

[0128] Example 1

[0129] In a 5 L stainless steel polymerization kettle, Material A1 was added, and stirring was started. When the temperature in the polymerization kettle reached 60 °C, 2.4 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.5 h (the first polymerization reaction generates polymerization chain R1, the same below), a sample was taken to test the molecular weight and microstructure. Then 62.4 mmol of n-butyllithium was added to the polymerization kettle, and then Material B1 was added, and the polymerization reaction was continued for 0.8 h (the second polymerization reaction generates polymerization chain R2 and polymerization chain R1-R2, the same below). After the monomers reacted completely, 0.318 g of silicon tetrachloride was added for coupling reaction for 0.4 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0130] It was measured that the number-average molecular weight of R1 in the polymer obtained in this example was 14560 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 15.0%; the number-average molecular weight of R2 was 5032 g / mol. Based on the mass of the butadiene structural unit in R2, the content of the 1,2-PB structural unit was 51.5%; the coupling efficiency was 60.0%.

[0131] Example 2

[0132] In a 5 L stainless steel polymerization kettle, Material A2 was added, and stirring was started. When the temperature in the polymerization kettle reached 65 °C, 3 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.6 h, a sample was taken to test the molecular weight and microstructure. Then 37.5 mmol of n-butyllithium was added to the polymerization kettle, and then Material B2 was added, and the polymerization reaction was continued for 0.9 h. After the monomers reacted completely, 1.91 g of silicon tetrachloride was added for coupling reaction for 0.5 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0133] The number-average molecular weight of R1 in the polymer obtained in this example was measured to be 11,895 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 18.4%; the number-average molecular weight of R2 was 7,817 g / mol. Based on the mass of the butadiene structural unit in R2, the content of the 1,2-PB structural unit was 55.3%; the coupling efficiency was 62.6%.

[0134] Example 3

[0135] In a 5 L stainless steel polymerization kettle, material A3 was added, and stirring was started. When the temperature in the polymerization kettle reached 70 °C, 11.25 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.7 h, samples were taken to test the molecular weight and microstructure. Then 15.75 mmol of n-butyllithium was added to the polymerization kettle, and then material B3 was added. The polymerization reaction was continued for 1 h. After the monomers reacted completely, 0.8 g of silicon tetrachloride was added for coupling reaction for 0.8 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0136] The number-average molecular weight of R1 in the polymer obtained in this example was measured to be 7,979 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 20.5%; the number-average molecular weight of R2 was 9,835 g / mol. Based on the mass of the butadiene structural unit in R2, the content of the 1,2-PB structural unit was 50.9%; the coupling efficiency was 57.3%.

[0137] Example 4

[0138] In a 5 L stainless steel polymerization kettle, material A4 was added, and stirring was started. When the temperature in the polymerization kettle reached 60 °C, 6 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.8 h, samples were taken to test the molecular weight and microstructure. Then 21 mmol of n-butyllithium was added to the polymerization kettle, and then material B4 was added. The polymerization reaction was continued for 0.8 h. After the monomers reacted completely, 1.07 g of silicon tetrachloride was added for coupling reaction for 0.6 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0139] The number-average molecular weight of R1 in the polymer obtained in this example was measured to be 14,896 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 20.0%; the number-average molecular weight of R2 was 9,808 / mol. Based on the mass of the butadiene structural unit in R2, the content of the 1,2-PB structural unit was 50.1%; the coupling efficiency was 51.4%.

[0140] Example 5

[0141] In a 5L stainless steel polymerization kettle, material A5 was added, and stirring was started. When the temperature in the polymerization kettle reached 70 °C, 6.48 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.7 h, a sample was taken to test the molecular weight and microstructure. Then 23.04 mmol of n-butyllithium was added to the polymerization kettle, and then material B5 was added. The polymerization reaction was continued for 1 h. After the monomers reacted completely, 1.17 g of silicon tetrachloride was added for a coupling reaction for 0.8 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0142] The number-average molecular weight of R1 in the polymer obtained in this example was measured to be 9,888 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 25.0%; the number-average molecular weight of R2 was 9,865 g / mol. The average content of the 1,2-PB structure in the polymer was 55.0%; the coupling efficiency was 59.6%.

[0143] Example 6

[0144] In a 5L stainless steel polymerization kettle, material A6 was added, and stirring was started. When the temperature in the polymerization kettle reached 75 °C, 8.1 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.6 h, a sample was taken to test the molecular weight and microstructure. Then 50.94 mmol of n-butyllithium was added to the polymerization kettle, and then material B6 was added. The polymerization reaction was continued for 0.9 h. After the monomers reacted completely, 2.6 g of silicon tetrachloride was added for a coupling reaction for 0.8 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80 °C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0145] The number-average molecular weight of R1 in the polymer obtained in this example was measured to be 7,909 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 28.1%; the number-average molecular weight of R2 was 4,956 g / mol. The average content of the 1,2-PB structure in the polymer was 57.8%; the coupling efficiency was 60.9%.

[0146] Comparative Example 1

[0147] In a 5L stainless steel polymerization kettle, material A2 was added, and stirring was started. When the temperature in the polymerization kettle reached 65°C, 3 mmol of n-butyllithium was added to the polymerization kettle. After reacting for 0.6 h, a sample was taken to test the molecular weight and microstructure. Then 37.5 mmol of n-butyllithium was added to the polymerization kettle, and then material B2 (tetrahydrofurfuryl ethyl ether was not added to B2) was added, and the polymerization reaction was continued for 0.9 h. After the monomers reacted completely, 1.91 g of silicon tetrachloride was added for coupling reaction for 0.5 h. Finally, isopropanol was added to terminate the reaction, and antioxidant 1076 was added. The rubber solution was treated by vacuum drying. The temperature of the vacuum oven was set at 80°C, the vacuum degree was -0.1 MPa, and vacuum drying was carried out for 60 minutes. The sample was reserved for use.

[0148] It was measured that the number-average molecular weight of R1 in the polymer obtained in this example was 11998 g / mol. Based on the mass of the butadiene structural unit in R1, the content of the 1,2-PB structural unit was 18.3%; the number-average molecular weight of R2 was 7898 g / mol. Based on the mass of the butadiene structural unit in R2, the content of the 1,2-PB structural unit was 18.4%; the coupling efficiency was 62.8%.

[0149] Application Examples and Comparative Examples

[0150] The low-molecular-weight polymer prepared in the above example was used as a rubber processing operation oil and compared with the traditional aromatic operation oil TDAE. Using the solution-polymerized styrene-butadiene rubber of Asahi Kasei Y031 brand in Japan as the base rubber, reinforcement was carried out using a silica system. 100 parts by weight of rubber, 60 parts by weight of silica selected from Rhodia's 165GR, 10 parts by weight of 8# reference carbon black, 15 parts by weight of operation oil, 3.0 parts by weight of zinc oxide, 2.0 parts by weight of stearic acid, 1.5 parts by weight of sulfur, 2.0 parts by weight of antioxidant 4020, 1.5 parts by weight of accelerator D, and 1.5 parts by weight of accelerator TBBS. The internal mixer was the American Farrell BR1600 type, and the cavity volume was 1.5 L; the flat vulcanizer was produced by Pan Shi Petrochemical Industry (Anhui) Co., Ltd., and the model was P-50-PCD-3L (vulcanization temperature was 150°C, vulcanization pressure was 20 MPa, and vulcanization time was 50 min). Vulcanized rubber was obtained.

[0151] Here, only the low-molecular-weight polymers obtained in Example 1, Example 2, and Example 3 were used as operation oils for application examples for illustration. The operation oil for Application Comparative Example 1 was the TDAE oil of the German Hanse Chemie V500 brand, and the operation oil for Application Comparative Example 2 was the polymer obtained in Comparative Example 1.

[0152] The properties of the obtained vulcanized rubber are shown in Table 1.

[0153] Table 1

[0154] Application Example 1 Application Example 2 Application Example 3 Application Comparative Example 1 Application Comparative Example 2 Tensile Strength / MPa 17.3 16.8 17.9 15.3 15.8 100% Modulus / MPa 3.4 3.3 3.2 3.1 3.2 300% Modulus / MPa 15.6 15.1 15.7 --- 14.8 Elongation at Break / % 422 403 399 288 413 Tear Strength / KN / m 22.5 23.3 22.9 20.5 22.1 <![CDATA[DIN wear / mm 3 > 105 102 109 136 104 Tanδ (0℃) 1.025 0.985 1.073 0.843 0.862 Tanδ (60℃) 0.089 0.091 0.088 0.112 0.108

[0155] As can be seen from the above results, the low-molecular-weight multi-structured monovinyl aromatic-conjugated diene polymer provided by the present invention realizes the coexistence of two structures with different benzene contents and different side-group contents in the polymer through a clever structural design. Therefore, the low-molecular-weight polymer provided by the present invention, when added to a rubber matrix as a rubber processing oil, endows the composite material with excellent wear resistance, relatively high wet skid resistance, and low rolling resistance. It is a preferable choice for the processing oil of a green tire tread compound with silica as the main reinforcing agent, making the tire product have excellent fuel economy, wet grip performance, and wear resistance at the same time.

[0156] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A mono-vinyl aromatic-conjugated diene polymer, characterized in that, The polymer contains a structure formed by coupling a monovinylarene-conjugated diene polymer chain R1, a monovinylarene-conjugated diene polymer chain R2, and a monovinylarene-conjugated diene polymer chain R1-monovinylarene-conjugated diene polymer chain R2. Among them, the number-average molecular weight of the monovinylarene-conjugated diene polymer chain R1 is 7,000-17,000 g / mol, the number-average molecular weight of the monovinylarene-conjugated diene polymer chain R2 is 4,000-12,000 g / mol. Based on the mass of the conjugated diene structural unit in the monovinylarene-conjugated diene polymer chain R1, the content of the conjugated diene side group structure in the monovinylarene-conjugated diene polymer chain R1 is 10-30%. Based on the mass of the conjugated diene structural unit in the monovinylarene-conjugated diene polymer chain R2, the content of the conjugated diene side group in the monovinylarene-conjugated diene polymer chain R2 is 50-65%.

2. The vinyl aromatic-conjugated diene polymer according to the claim, wherein The conjugated diene is selected from one or more of butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, and 2,3-dimethylbutadiene; Preferably, the conjugated diene is butadiene.

3. The vinyl aromatic-conjugated diene polymer according to claim 1, wherein, The coupling efficiency is 40-80% by weight, preferably 50-65% by weight; Preferably, the coupling structural unit is from one or more of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane, and dichlorosilane, preferably from silicon tetrachloride.

4. The vinyl aromatic-conjugated diene polymer according to any one of claims 1-3, wherein Based on the mass of the monovinylarene-conjugated diene polymer, the mass content of the monovinylarene-conjugated diene polymer chain R1 is 10-25%, and the mass content of the monovinylarene-conjugated diene polymer chain R2 is 75-90%; Preferably, based on the mass of the monovinylarene-conjugated diene polymer chain R1, the mass content of the monovinylarene structural unit in the monovinylarene-conjugated diene polymer chain R1 is 25-45%, preferably 30-40%; Preferably, based on the mass of the monovinylarene-conjugated diene polymer chain R2, the mass content of the monovinylarene in the monovinylarene-conjugated diene polymer chain R2 is 5-25%, preferably 10-20%.

5. The vinyl aromatic-conjugated diene polymer according to any one of claims 1-3, wherein, The monovinylarene is selected from one or more of styrene, vinyltoluene, α-methylstyrene, 4-tert-butylstyrene, 4-methylstyrene, 3,5-diethylstyrene, 3,5-di-n-butylstyrene, 4-n-propylstyrene, and 4-dodecylstyrene; Preferably, the monovinylarene is styrene.

6. A method for preparing a mono vinyl aromatic-conjugated diene polymer, characterized in that, The method comprises the following steps: 1) A step of carrying out a first polymerization reaction on a material A containing a monovinylarene monomer, a conjugated diene monomer, and a nonpolar solvent in the presence of an anionic initiator a; 2) A step of carrying out a second polymerization reaction on the first polymerization reaction product obtained in step 1) with a material B containing a monovinylarene monomer, a conjugated diene monomer, a polar regulator, and a nonpolar solvent in the presence of an anionic initiator b; 3) A step of subjecting the second polymerization product obtained in step 2) to a coupling reaction in the presence of a coupling agent.

7. The method according to claim 6, wherein, The material A further contains a polarity regulator, and the dosage of the polarity regulator in the material A is 50 ppm or less, preferably 10 - 40 ppm; Preferably, the dosage of the polarity regulator in the material B is 100 - 600 ppm, preferably 200 - 400 ppm.

8. The method according to claim 6, wherein Based on the total mass of all polymerization monomers, the mass content of the polymerization monomers in the material A is 10 - 25%, and the mass content of the polymerization monomers in the material B is 75 - 90%.

9. The method according to any one of claims 6-8, wherein, The mass percentage content of the monovinyl aromatic hydrocarbon monomer in the material A is 25 - 45%, preferably 30 - 40%; Preferably, the mass percentage content of the monovinyl aromatic hydrocarbon monomer in the material B is 25 - 45%, preferably 30 - 40%.

10. The method according to any one of claims 6 - 8, wherein, The molar ratio of the anionic initiator a to the anionic initiator b is 1:1.4 - 26.

11. The method according to any one of claims 6-8, wherein, The conjugated diene is selected from one or more of butadiene, isoprene, 1,3 - pentadiene, 1,3 - hexadiene, and 2,3 - dimethylbutadiene; Preferably, the conjugated diene is butadiene.

12. The method according to any one of claims 6-8, wherein The monovinyl aromatic hydrocarbon is selected from one or more of styrene, vinyltoluene, α - methylstyrene, 4 - tert - butylstyrene, 4 - methylstyrene, 3,5 - diethylstyrene, 3,5 - di - n - butylstyrene, 4 - n - propylstyrene, and 4 - dodecylstyrene; Preferably, the monovinyl aromatic hydrocarbon is styrene.

13. The method according to any one of claims 6 - 8, wherein, The anionic initiator a and the anionic initiator b are each independently a compound having an RLi structure, where R is a linear or branched alkyl group having 1 to C 10 carbon atoms; Preferably, the R is selected from methyl, ethyl, n - propyl, isopropyl, n - butyl, sec - butyl, isobutyl, tert - butyl, n - pentyl, isopentyl, tert - pentyl, neopentyl, n - hexyl, n - heptyl, n - octyl, and n - decyl.

14. The method according to any one of claims 6 - 8, wherein The polarity regulator is selected from one or more of diethyl ether, dibutyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofurfuryl ether, dioxane, crown ether, triethylamine, tetramethylethylenediamine, hexamethylphosphoric triamide, potassium tert - butoxide, potassium tert - pentoxide, potassium laurate, potassium alkylbenzenesulfonate, and sodium alkylbenzenesulfonate, preferably tetrahydrofurfuryl ether.

15. The method according to any one of claims 6-8, wherein, The coupling agent is selected from one or more of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, epoxidized castor oil, divinylbenzene, methoxysilane, dibromosilane, and dichlorosilane, preferably silicon tetrachloride.

16. A monovinyl aromatic hydrocarbon - conjugated diene polymer prepared by the method according to any one of claims 6 - 15.

17. Use of the monovinyl aromatic hydrocarbon - conjugated diene polymer according to any one of claims 1 - 5 and 16 as an operating oil in a tire tread rubber.

Images