Modified conjugated diene polymer composition, preparation method thereof, and tire

Abstract

The present application discloses a modified conjugated diene polymer composition, a preparation method thereof, and a tire. The modified conjugated diene polymer composition comprises: a modified conjugated diene polymer comprising aromatic vinyl monomer structural units and conjugated diene monomer structural units, wherein the aromatic vinyl monomer structural units having molecular chains of eight or more consecutive aromatic vinyl monomers account for less than 10% by mass of the total amount of the aromatic vinyl monomer structural units; and a silicon-based inorganic filler, wherein the silicon-based inorganic filler is present in an amount of 60 to 200 parts by mass per 100 parts by mass of the modified conjugated diene polymer. The modified conjugated diene polymer composition exhibits an excellent balance between low hysteresis loss and handling stability, a characteristic associated with safety, and possesses sufficient breaking strength for practical applications.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a modified conjugated diene polymer composition, a preparation method thereof, and a tire. Background Art

[0002] The increasing demand for lower fuel consumption in automobiles necessitates improvements in the materials used in automotive tires, particularly the tire treads that come into contact with the road. In recent years, there has been a demand for materials that exhibit low rolling resistance, or hysteresis loss, and, consequently, low fuel consumption. Furthermore, from a safety perspective, tire tread materials must exhibit excellent anti-skid properties and sufficient rigidity to ensure handling stability.

[0003] Materials that meet these requirements include materials containing rubber, carbon black, and reinforcing fillers such as silicon. For example, the use of silicon-containing materials can achieve a better balance between low hysteresis loss and anti-slip properties. Furthermore, attempts to reduce hysteresis loss have been made by introducing functional groups with affinity or reactivity for silicon into the molecular ends of highly active rubber to improve the dispersibility of silicon in the material. Furthermore, bonding with silicon particles reduces the activity of the rubber molecular ends, thereby reducing the activity of the rubber molecular ends.

[0004] Patent Documents 1 to 3 propose modified diene rubbers obtained by reacting amino-containing alkoxysilanes with the active ends of polymers, and compositions thereof with silicon. The modified polymer, in which functional groups highly reactive with silicon are introduced into the rubber molecular ends, reacts with silicon particles during the blending process, resulting in fine dispersion of silicon in the composition, thereby improving low hysteresis loss properties.

[0005] However, the microdispersion of silicon reduces the rigidity (dynamic storage modulus) of the rubber composition after vulcanization, and when used as a tire tread, this tends to deteriorate handling stability. Thus, rubber compositions obtained by mixing modified polymers with silicon-based inorganic fillers in a rubber blender suffer from an inadequate balance between low hysteresis loss and handling stability.

[0006] Therefore, an object of the present invention is to provide a rubber composition for tire treads that suppresses a decrease in dynamic storage modulus in a rubber composition containing a modified conjugated diene polymer and a silicone filler and can improve the balance between low hysteresis loss and steering stability.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-290355

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 11-189616

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2003-171418. Summary of the Invention

[0012] Means used to solve technical problems.

[0013] In order to solve at least one of the technical problems existing in the above-mentioned prior art, the present inventors have conducted in-depth research and found that by controlling the composition and content of the aromatic vinyl monomer structural units in the modified conjugated diene polymer composition used as a raw material for making tire treads, the dynamic storage modulus (E′) and the loss tangent (tanδ) of the composition after vulcanization measured at 50°C can satisfy a specific relationship. This results in a conjugated diene polymer composition having an excellent balance between low hysteresis loss and handling stability, and sufficient destructive properties for practical use, thereby completing the present invention.

[0014] Specifically, the first aspect of the present invention provides a modified conjugated diene polymer composition, characterized in that it includes: a modified conjugated diene polymer, including an aromatic vinyl monomer structural unit and a conjugated diene monomer structural unit, wherein the content of the aromatic vinyl monomer structural unit having a molecular chain of more than 8 consecutive aromatic vinyl monomers accounts for less than 10% by mass of the total amount of the aromatic vinyl monomer structural unit, and a silicon-based inorganic filler, wherein the silicon-based inorganic filler is 60 to 200 parts by mass relative to 100 parts by mass of the modified conjugated diene polymer.

[0015] In the modified conjugated diene polymer composition, the ratio of the molecular chain having 8 or more consecutive structural units derived from the aromatic vinyl monomer is preferably 8% by mass or less, and more preferably 5% by mass or less.

[0016] In the modified conjugated diene polymer composition, the silicon-based inorganic filler is preferably present in an amount of 70 to 150 parts by mass, and more preferably 80 to 120 parts by mass.

[0017] In the modified conjugated diene polymer composition, the aromatic vinyl monomer is at least one selected from styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, and 2,4,6-trimethylstyrene, with styrene being particularly preferred.

[0018] In the modified conjugated diene polymer composition, the conjugated diene monomer is at least one selected from 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene, preferably 1,3-butadiene and isoprene, and more preferably 1,3-butadiene.

[0019] In the modified conjugated diene polymer composition, the total amount of the aromatic vinyl monomer structural units is 35% by mass or more, preferably 40% by mass or more, and preferably 50% by mass or less, relative to 100 parts by mass of the modified conjugated diene polymer.

[0020] In the modified conjugated diene polymer composition, the vinyl bond content (1,2-bond content) in the conjugated diene monomer structural unit is 10 mol% or more, preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more. From the perspective of wear resistance and breaking strength of the vulcanized product, it is preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 60 mol% or less.

[0021] In the modified conjugated diene polymer composition, the modified conjugated diene polymer has a molecular weight distribution (Mw / Mn) of 1.1 or greater, preferably 1.2 or greater, and preferably 1.5 or less, more preferably 1.4 or less.

[0022] In the modified conjugated diene polymer composition, the modified conjugated diene polymer composition further comprises: at least one of carbon black, metal oxide, metal hydroxide, silane coupling agent, vulcanizing agent, vulcanization accelerator, and softener.

[0023] In the modified conjugated diene polymer composition, the weight-average molecular weight of the modified conjugated diene polymer is preferably 200,000 to 2,000,000. The weight-average molecular weight is more preferably 300,000 to 300,000, further preferably 400,000 to 400,000, and even more preferably 500,000 to 500,000; more preferably 1,800,000 to 1,800,000, further preferably 1,500,000 to 1,000,000, and even more preferably 1,000,000 to 1,000,000.

[0024] In the modified conjugated diene polymer composition, the modified conjugated diene polymer composition after vulcanization was tested under the conditions of a frequency of 10 Hz, a dynamic strain of 3%, and a temperature of 50° C. The modified conjugated diene polymer composition after vulcanization satisfied the following formula (1):

[0025] T≤0.01×E+0.05…(1)

[0026] In formula (1), E is the dynamic storage modulus E', T is the loss tangent tanδ, and the dynamic storage modulus E is 2 to 10 MPa.

[0027] The second aspect of the present invention provides a method for preparing a modified conjugated diene polymer composition, characterized in that it comprises the following steps: S1: copolymerizing at least one conjugated diene monomer and at least one aromatic vinyl monomer in a solvent in the presence of an initiator to obtain a conjugated diene polymer; S2: modifying the conjugated diene polymer using a modifier to obtain a modified conjugated diene polymer; S3: mixing the modified conjugated diene polymer with a silicon inorganic filler to obtain the modified conjugated diene polymer composition, wherein the modifier is a modifier having at least one silicon atom and at least one nitrogen atom in one molecule and having three or more reactive sites.

[0028] In the preparation method of the above-mentioned modified conjugated diene polymer composition, the initiator is one or more selected from ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, and the reaction product of diisopentenylbenzene and butyllithium.

[0029] In the preparation method of the modified conjugated diene polymer composition, the modifier is selected from [3-(dimethylamino)propyl]triethoxysilane, [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]triethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [2-(dimethylamino)ethyl]triethoxysilane, [2-(dimethylamino)ethyl]trimethoxysilane, [3-(dimethylamino)propyl]diethoxymethylsilane, [3-dibutylaminopropyl]triethoxysilane, 3-hexamethyleneimino One or more selected from the group consisting of propyltriethoxysilane, 3-hexamethyleneiminopropyltrimethoxysilane, hexamethyleneiminomethyltrimethoxysilane, hexamethyleneiminomethyltriethoxysilane, 2-hexamethyleneiminoethyltriethoxysilane, 2-hexamethyleneiminoethyltrimethoxysilane, 3-pyrrolidinyloxypropyltriethoxysilane, 3-pyrrolidinyloxypropyltrimethoxysilane, 3-heptamethyleneiminopropyltriethoxysilane, 3-dodecamethyleneiminopropyltriethoxysilane, and 1-[3-(triethoxysilyl)propyl]-4-methylpiperazine.

[0030] In the method for preparing the modified conjugated diene polymer composition, in step S3 , the modified conjugated diene polymer and the silicon-based inorganic filler are mixed once using a rubber mixer having a dispersive mixing rotor.

[0031] A third aspect of the present invention provides a tire comprising the conjugated diene polymer composition.

[0032] Effects of the Invention

[0033] According to the present invention, a conjugated diene polymer composition and a tire are provided, which, after vulcanization of a rubber composition containing a modified conjugated diene polymer and a silicon-based inorganic filler, exhibit an excellent balance between safety-related properties such as low hysteresis loss and handling stability, and have a breaking strength sufficient for practical use. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 3 is a distribution diagram showing the test results of the dynamic storage modulus and loss function of Examples 1 to 4 and Comparative Examples 1 and 2 according to the embodiment of the present invention. DETAILED DESCRIPTION

[0035] Below, an embodiment for implementing the present invention (hereinafter referred to as "this embodiment") is described in detail. This embodiment below is an example for illustrating the present invention and is not intended to limit the present invention by the following content. The present invention can be appropriately modified and deformed within the scope of its purpose.

[0036] Modified conjugated diene polymers

[0037] In one embodiment, the conjugated diene polymer composition includes a modified conjugated diene polymer. In one embodiment, the "modified conjugated diene polymer" of the present disclosure refers to a modified conjugated diene polymer modified with a modifier containing a functional group reactive with a silicon-based inorganic filler.

[0038] The modified conjugated diene polymer can provide a sulfur-added product in which silicon as a reinforcing filler is finely dispersed and excellent low hysteresis is achieved.

[0039] The modified conjugated diene polymer of this embodiment is a random copolymer comprising structural units based on an aromatic vinyl monomer (sometimes referred to as "aromatic vinyl monomer structural units" in this disclosure) and structural units based on a conjugated diene monomer (sometimes referred to as "conjugated diene monomer structural units" in this disclosure).

[0040] The "random copolymer" of the present embodiment refers to a copolymer having a molecular chain of 8 or more continuous structural units derived from an aromatic vinyl monomer with a ratio of 10% by mass or less relative to the overall structural units derived from an aromatic vinyl monomer. Here, the content of the molecular chain having 8 or more continuous structural units derived from an aromatic vinyl monomer can be obtained by measuring a spectrum obtained by dissolving a conjugated diene polymer in a heavy chloroform solvent using a nuclear magnetic resonance apparatus (1H-NMR) with a proton resonance frequency of 150 MHz or more. Specifically, it is measured by the method described in the examples described later. From the viewpoint of low hysteresis loss when making a sulfur-added product, the ratio of the molecular chain having 8 or more continuous structural units derived from an aromatic vinyl monomer is preferably 8% or less by mass, more preferably 5% or less by mass.

[0041] The aromatic vinyl monomer is not particularly limited, and examples thereof include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, and 2,4,6-trimethylstyrene. These aromatic vinyl monomers may be used alone or in combination of two or more. Among them, styrene is particularly preferred from a practical standpoint such as easy availability of the monomer.

[0042] The conjugated diene monomer is not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene. These conjugated diene monomers may be used alone or in combination of two or more. 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

[0043] The content of aromatic vinyl monomer structural units (ST) in the modified conjugated diene polymer is preferably 35% by mass or greater, and more preferably 40% by mass or greater, from the perspective of improving the dispersibility of the silicon-based inorganic filler in the conjugated diene polymer composition and enhancing the mechanical properties and anti-skid properties of the sulfur-added product. To avoid reducing the wear resistance of the sulfur-added product and adjusting the glass transition temperature of the rubber composition, the content of aromatic vinyl monomer structural units is 50% by mass or less. The content of aromatic vinyl monomer structural units is measured using an ultraviolet spectrophotometer (UV meter), more specifically, by the method described in the Examples below.

[0044] In the modified conjugated diene polymer of the present embodiment, from the perspective of controlling the glass transition temperature of the rubber composition, for example, the balance between low hysteresis loss and anti-skid properties when making a vulcanized product for tire treads and the wear resistance of the vulcanized product, the vinyl bond content (1,2-bond content) in the conjugated diene monomer structural unit is 10 mol% or more, preferably 20 mol% or more, more preferably 25 mol% or more, and further preferably 30 mol% or more. From the perspective of the wear resistance and breaking strength of the vulcanized product, it is preferably 70 mol% or less, more preferably 65 mol% or less, and further preferably 60 mol% or less. Here, when the conjugated diene polymer is a copolymer of butadiene and styrene, the vinyl bond content in the butadiene monomer structural unit can be obtained by the Hampton method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, it is measured by the method described in the Examples described later.

[0045] The molecular weight distribution (Mw / Mn) of the modified conjugated diene polymer of this embodiment is preferably 1.1 or more, more preferably 1.2 or more, from the viewpoint of processability and tensile strength and wear resistance of the sulfurized product. From the viewpoint of dispersibility of the silicon-based inorganic filler and low hysteresis loss when the sulfurized product is prepared, it is preferably 1.5 or less, more preferably 1.4 or less.

[0046] The weight-average molecular weight of the modified conjugated diene polymer is preferably 200,000 to 2,000,000 from the viewpoint of the shape stability (particularly cold flow resistance) of the rubber component containing the conjugated diene polymer and the tensile strength and wear resistance of the vulcanized rubber composition. The weight-average molecular weight is more preferably 300,000 or more, further preferably 400,000 or more, and even more preferably 500,000 or more; and more preferably 1,800,000 or less, further preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0047] The weight average molecular weight of the modified conjugated diene polymer is a value measured by GPC (Gel permeation chromatography), and more specifically, can be measured by the method described in Examples below.

[0048] <Manufacturing of modified conjugated diene polymers>

[0049] The polymerization method for the modified conjugated diene polymer is not particularly limited as long as the above-mentioned specific physical properties can be obtained. Any of solution polymerization, gas phase polymerization, and bulk polymerization can be used. From the perspective of commercial production, solution polymerization is particularly preferred. Furthermore, the polymerization method may be batch or continuous, with batch polymerization being particularly preferred.

[0050] When using a solution polymerization method, the monomer concentration in the solution is 5% by mass or greater, preferably 10% by mass or greater. A monomer concentration of 5% by mass or greater yields a sufficient amount of conjugated diene polymer, which tends to reduce costs. Alternatively, the monomer concentration in the solution is 50% by mass or less, preferably 30% by mass or less. A monomer concentration of 50% by mass or less results in a low solution viscosity, ease of stirring, and facilitates polymerization.

[0051] Polymerization initiator

[0052] The modified conjugated diene polymer is obtained by anionic polymerization in one embodiment. As the polymerization initiator for anionic polymerization, there is no particular limitation, but an organic lithium compound is preferably used. As the organic lithium compound, an organic lithium compound having an alkyl group with a carbon number of 2 to 20 is preferably used, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclopentyl lithium, the reaction product of diisopentenylbenzene and butyl lithium, etc. Among them, from the viewpoints of ease of use and safety, n-butyl lithium or sec-butyl lithium is preferred.

[0053] Aggregation method

[0054] The method for producing a modified conjugated diene copolymer by anionic polymerization using a polymerization initiator is not particularly limited, and conventionally known methods can be used. Specifically, the target conjugated diene copolymer can be obtained by polymerizing styrene, 1,3-butadiene, etc. in a hydrocarbon solvent such as a linear aliphatic, alicyclic, or aromatic hydrocarbon compound, for example, using butyl lithium as a polymerization initiator, in the presence of a polar compound as needed.

[0055] The hydrocarbon solvent is preferably a hydrocarbon solvent having 3 to 8 carbon atoms, and examples thereof include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propylene, 1-butene, isobutylene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, etc. These may be used alone or in combination of two or more.

[0056] Polar compounds

[0057] When producing conjugated diene polymers, the following polar compounds are added in small amounts for the purpose of random copolymerization of aromatic vinyl monomers and conjugated diene monomers, as vinylating agents for further controlling the microstructure of the conjugated diene portion, and further for the purpose of improving the polymerization rate.

[0058] Examples of polar compounds include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxetanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipyridinyldione, trimethylamine, triethylamine, pyridine, and quinacridone; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butoxide, sodium tert-butoxide, and sodium carbamate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

[0059] The amount of the polar compound used can be selected according to the purpose and the degree of effect. Generally, the amount of the polar compound used is 0.01 to 100 mol per 1 mol of lithium in the anionic polymerization initiator.

[0060] Such a polar compound (vinylating agent) can be used in an appropriate amount as a microstructure modifier of the olefin portion of the polymer, depending on the desired vinyl bond amount.

[0061] Most polar compounds also have an effective randomizing effect in the copolymerization of conjugated diene monomers and aromatic vinyl monomers, and can adjust the distribution of aromatic vinyl monomers and the amount of styrene blocks.

[0062] The randomization method is described in Japanese Patent Application Laid-Open No. 59-140211, and a method of intermittently adding a portion of 1,3-butadiene during the copolymerization process can be used.

[0063] Polymerization conditions

[0064] The polymerization temperature of the conjugated diene polymer is not particularly limited as long as it is a temperature at which living anionic polymerization can proceed. However, from the perspective of productivity, it is preferably 0°C or higher. From the perspective of ensuring a sufficient amount of modification reaction at the active terminals after completion of the polymerization, it is preferably 120°C or lower. The range of 20 to 100°C is more preferred, and the range of 30 to 85°C is even more preferred.

[0065] Regarding the polymerization temperature, considering that polymerization is an exothermic reaction, it can be controlled by adjusting the feed temperature of the monomer and solvent, controlling the monomer concentration, and performing cooling or heating from outside the reactor.

[0066] The conjugated diene monomer, aromatic vinyl monomer, and polymerization solvent may be treated with an organometallic compound to remove impurities such as dienes and alkynes, either individually or in a mixed solution, before subjecting them to the prepolymerization reaction. This can result in a high concentration of active terminals in the polymer before the modification reaction, leading to a higher modification rate.

[0067] Modification reaction

[0068] The modified conjugated diene polymer of this embodiment is modified at the polymerization active terminal by a modifying agent.

[0069] In detail, the above-mentioned anionic initiator is used to copolymerize the above-mentioned conjugated diene monomer and aromatic vinyl monomer to prepare a conjugated diene polymer, and the polymerization active end of the conjugated diene polymer is reacted with a modifier having one tertiary amino group and one trialkoxysilyl group in the molecule to obtain the modified conjugated diene copolymer of this embodiment.

[0070] When a modifier having two or more tertiary amino groups or two or more trialkoxysilyl groups is used, the silicon in the rubber composition is excessively finely dispersed, resulting in a significant decrease in the storage modulus. This deteriorates the handling stability of the tire when used in a tire tread, which is not preferred.

[0071] The amount of the modifier added is preferably such that the number of moles of the functional group of the modifier is 0.1 mol or more and 0.8 mol or less per mol of the polymerization catalyst (eg, organic monolithium compound) used in the polymerization process.

[0072] Examples of the modifier include, but are not limited to, alkoxysilane compounds having a non-cyclic amino group and alkoxysilane compounds having a cyclic amino group.

[0073] Specific examples of the alkoxysilane compound having a non-cyclic amino group are shown below.

[0074] For example, [3-(dimethylamino)propyl]triethoxysilane, [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]triethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [2-(dimethylamino)ethyl]triethoxysilane, [2-(dimethylamino)ethyl]trimethoxysilane, [3-(dimethylamino)propyl]diethoxymethylsilane, [3-dibutylaminopropyl]triethoxysilane, and the like can be cited.

[0075] Specific examples of the alkoxysilane compound having a cyclic amino group are shown below.

[0076] For example, 3-hexamethyleneiminopropyltriethoxysilane, 3-hexamethyleneiminopropyltrimethoxysilane, hexamethyleneiminomethyltrimethoxysilane, hexamethyleneiminomethyltriethoxysilane, 2-hexamethyleneiminoethyltriethoxysilane, 2-hexamethyleneiminoethyltrimethoxysilane, 3-pyrrolidinyloxypropyltriethoxysilane, 3-pyrrolidinyloxypropyltrimethoxysilane, 3-heptamethyleneiminopropyltriethoxysilane, 3-dodecamethyleneiminopropyltriethoxysilane, 1-[3-(triethoxysilyl)propyl]-4-methylpiperazine, etc. can be mentioned.

[0077] The reaction temperature in the reaction process is preferably the same as the polymerization temperature of the conjugated diene polymer, more preferably 0°C to 120°C, and even more preferably 50°C to 100°C.

[0078] The reaction time in the reaction process is preferably 10 seconds or longer, more preferably 30 seconds or longer. In one embodiment, the reaction time may be 15 minutes or shorter, or 10 minutes or shorter.

[0079] The modifier can be diluted with an inert solvent and then continuously supplied to the reactor. When the polymerization process is a batch process, the modifier can be added to the polymerization reactor or the polymerization product can be transferred to another reactor for the reaction process.

[0080] The time from the polymerization process to the reaction process is preferably short from the viewpoint of achieving a high modification rate, preferably within 10 minutes, and more preferably within 5 minutes. It should be noted that the time from the polymerization process to the reaction process, when the polymerization process is a batch process, refers to the time from reaching the peak polymerization temperature to the addition of the modifier; when the polymerization process is a continuous process, it refers to the time from the discharge of the reaction solution containing the conjugated diene polymer from the polymerization reactor to the addition of the modifier.

[0081] Reaction stopped

[0082] Anionic polymerization can be stopped by adding a reaction terminator commonly used in this area. As such a reaction terminator, it is not particularly limited, and polar solvents (for example, alcohols such as methanol, ethanol, isobutanol or acetic acid, etc.) with active protons and their mixed solutions or mixed solutions of the above-mentioned polar solvents or more and non-polar solvents such as hexane and cyclohexane can be enumerated. The addition amount of the reaction terminator is usually sufficient relative to the anionic polymerization initiator at equal molar amount or about 2 times the molar amount.

[0083] At the end of the polymerization process of the conjugated diene polymer, a deactivator, neutralizer, etc. may be added as needed. Examples of deactivators include, but are not limited to, water, methanol, ethanol, isobutanol, and other alcohols. The end of the polymerization process here refers to a state where more than 95 mol% of the added monomers have been consumed in the polymerization. Examples of neutralizers include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and basatik acid (a mixture of carboxylic acids with multiple branches and a carbon number of 9 to 11, centered around 10), aqueous solutions of inorganic acids, and carbonic acid gas.

[0084] Use of rubber stabilizers

[0085] From the perspective of preventing gel formation and improving processing stability, it is preferable to add a rubber stabilizer at the end of the polymerization process of the conjugated diene polymer. Existing stabilizers can be used as rubber stabilizers, and antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol are preferred, but are not limited to these.

[0086] Use of rubber softener

[0087] At the end of the polymerization process of the conjugated diene polymer, a rubber softener may be added as needed to improve the productivity of the polymer and the processability after adding inorganic fillers when manufacturing the conjugated diene polymer composition. The rubber softener is not particularly limited, and examples thereof include stretching oil, liquid rubber, resin, etc. The liquid rubber can be selected from the examples described above. From the perspectives of processability, productivity, and economy, stretching oil is preferred.

[0088] As a method for adding the rubber softener to the conjugated diene polymer, a method of adding the rubber softener to the polymer solution, mixing, and then removing the solvent from the obtained polymer solution containing the rubber softener is preferred, but the method is not limited thereto.

[0089] Preferred extending oils include, for example, aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils having a polycyclic aromatic (PCA) content of 3% by mass or less based on the IP346 method are preferred from the perspectives of environmental safety, oil leakage prevention, and wetland adhesion properties. Examples of aromatic substitute oils include TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) as described in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), as well as RAE (Residual Aromatic Extracts).

[0090] From the perspective of suppressing the aging of the cured product, the content of the stretching oil is preferably 37.5 parts by mass or less, more preferably 30 parts by mass or less, further preferably 25 parts by mass or less, and most preferably 20 parts by mass or less, relative to 100 parts by mass of the conjugated diene polymer. In one embodiment, the above content is 5 parts by mass or more, 10 parts by mass or more, or 15 parts by mass or more.

[0091] Solvent removal

[0092] As a method for removing the solvent from a polymer solution containing a branched conjugated diene polymer to obtain a branched conjugated diene polymer, existing methods can be used. Examples of such methods include: a method in which the solvent is separated by distillation, the polymer is filtered out, and then the polymer is dehydrated and dried to obtain the polymer; a method in which the polymer solution is concentrated in a rinse tank and then devolatilized using a head extruder; and a method in which direct devolatilization is performed using a blower or the like.

[0093] Modified conjugated diene polymer composition

[0094] Regarding the conjugated diene polymer composition of this embodiment, relative to 100 parts by mass of the rubber component containing the modified conjugated diene polymer described above, it contains 60 to 200 parts by mass of a silicone inorganic filler, and the dynamic storage modulus E′(E) of the rubber composition after vulcanization measured under the conditions of a frequency of 10 Hz, a dynamic distortion of 3%, and a temperature of 50°C is in the range of 2 MPa to 10 MPa, and the dynamic storage modulus and the loss tangent tanδ(T) satisfy the following formula (1).

[0095] T≤0.0125xE+0.035(1)

[0096] The dynamic storage modulus is preferably in the range of 4 MPa to 9 MPa. A dynamic storage modulus less than 2 MPa is not preferred for use in tire treads because it deteriorates handling stability. Furthermore, a dynamic storage modulus exceeding 10 MPa deteriorates the dispersibility of the silicone inorganic filler, making it impossible to obtain a rubber composition with excellent low hysteresis loss properties.

[0097] Furthermore, the loss positive tan δ satisfies the formula (1), thereby obtaining a conjugated diene polymer composition having an excellent balance between steering stability and low hysteresis loss.

[0098] Rubber ingredients

[0099] The rubber component herein may include rubbers other than modified conjugated diene polymers, but is typically composed of a diene polymer. Examples of such rubbers include, but are not limited to, conjugated diene polymers or hydrogenates thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenates thereof, block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenates thereof, diene copolymers such as natural rubber, and non-diene copolymers.

[0100] Specifically, styrene-based elastomers such as butadiene rubber or its hydrogenate, isoprene rubber or its hydrogenate, styrene-butadiene rubber or its hydrogenate, styrene-butadiene block copolymer or its hydrogenate, styrene-isoprene block copolymer or its hydrogenate, and acrylonitrile-butadiene rubber or its hydrogenate are included, but are not limited thereto.

[0101] Silicone inorganic fillers

[0102] As the silicon-based inorganic filler contained in the conjugated diene-based polymer composition of the present embodiment, solid particles having SiO 2 or Si 3 Al as a main component of the structural unit can be used.

[0103] For example, inorganic fibrous substances such as silicon, clay, talc, mica, diatomaceous earth, stebanite, montmorillonite, zeolite, and glass fiber can be mentioned.

[0104] Furthermore, a silicon-based inorganic filler whose surface has been hydrophobized or a mixture of a silicon-based inorganic filler and an inorganic filler other than silicon-based fillers may also be used.

[0105] Among them, silicone and glass fiber are preferred, and silicone is more preferred.

[0106] As the silicon, dry silicon, wet silicon, synthetic silicate silicon, etc. can be used. Among them, wet silicon is preferred because it has the most significant effect of improving the breakage characteristics and the anti-slip property.

[0107] In the conjugated diene polymer composition of the present embodiment, from the viewpoint of obtaining practically good wear resistance and breakage characteristics, the nitrogen adsorption specific surface area of the silicon-based inorganic filler determined by the BET adsorption method is preferably 170 to 300 m 2 / g, more preferably 200 to 300 m 2 / g.

[0108] As described above, the amount of the silicone inorganic filler in the conjugated diene polymer composition is 60 to 200 parts by mass, preferably 70 to 150 parts by mass, and more preferably 80 to 120 parts by mass per 100 parts by mass of the rubber component containing the modified conjugated diene polymer.

[0109] If the amount of the silicone inorganic filler is less than 60 parts by mass, the tire tread cannot exhibit good wear resistance and damage characteristics for practical use. On the other hand, if it exceeds 200 parts by mass, the dispersibility of the silicone inorganic filler deteriorates, the processability of the composition deteriorates, and the mechanical strength decreases, which is not preferred.

[0110] Carbon black

[0111] In the conjugated diene polymer composition of the present embodiment, carbon black may be added as a reinforcing filler other than the silicon-based inorganic filler.

[0112] Carbon black can be SRF, FEF, HAF, ISAF, SAF and other types of carbon black, preferably with a nitrogen adsorption specific surface area of 50m 2 / g or more and carbon black with a DBP oil absorption of 80ml / 100g.

[0113] The amount of carbon black blended is preferably 0.5 to 100 parts by mass, more preferably 3 to 100 parts by mass, and even more preferably 5 to 50 parts by mass per 100 parts by mass of the rubber component containing 20 parts by mass or more of the modified conjugated diene polymer.

[0114] In order to achieve the performance required for applications such as tires, such as dry grip performance and conductivity, it is preferably added in an amount of 0.5 parts by mass or more, and preferably 100 parts by mass or less from the viewpoint of dispersibility.

[0115] Metal oxides, metal hydroxides

[0116] In addition, in addition to the silicon-based inorganic filler and carbon black, a metal oxide or a metal hydroxide may be added to the conjugated diene polymer composition of the present embodiment.

[0117] Metal oxides refer to solid particles whose main component is a structural unit of the chemical formula MxOy (M is a metal atom, and x and y are integers of 1 to 6). Examples of these particles include aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide. Furthermore, mixtures of metal oxides and inorganic fillers other than metal oxides may also be used.

[0118] Metal hydroxides include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, and the like.

[0119] (Silane coupling agent)

[0120] Furthermore, the conjugated diene polymer composition of the present embodiment may further contain a silane coupling agent.

[0121] The silane coupling agent has the function of strengthening the interaction between the rubber component and the silicone inorganic filler, and has groups having affinity or bonding properties corresponding to the rubber component and the silicone inorganic filler, respectively.

[0122] Examples of the silane coupling agent include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0123] The amount of the silane coupling agent added is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 15 parts by mass, relative to 100 parts by mass of the silicon-based inorganic filler.

[0124] If the amount of the silane coupling agent blended is less than 0.1 parts by mass relative to 100 parts by mass of the silicon-based inorganic filler, no effective blending effect can be obtained, and an amount exceeding 30 parts by mass is not necessary.

[0125] Vulcanizing agent

[0126] The modified conjugated diene copolymer composition of the present embodiment may be a vulcanized composition subjected to a vulcanization treatment using a vulcanizing agent.

[0127] As the vulcanizing agent, for example, free radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds can be used.

[0128] Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfide compounds, etc.

[0129] The amount of the vulcanizing agent used is usually 0.01 to 20 parts by mass, preferably 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component containing the modified conjugated diene polymer.

[0130] As the vulcanization method, a conventional method can be used, and the vulcanization temperature can be set to, for example, 120 to 200°C, preferably 140 to 180°C.

[0131] Vulcanization accelerators and vulcanization aids

[0132] Furthermore, during vulcanization, a vulcanization accelerator may be used as needed.

[0133] As the vulcanization accelerator, existing materials can be used, for example, sulfonamide-based, guanidine-based, dithiamide-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, dithiocarbamate-based vulcanization accelerators, etc. In addition, zinc oxide, stearic acid, etc. can be used as the vulcanization auxiliary agent.

[0134] The amount of the vulcanization accelerator used is generally 0.01 to 20 parts by mass, preferably 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component containing the modified conjugated diene polymer.

[0135] Rubber softener

[0136] The conjugated diene polymer composition of the present embodiment may contain a rubber softener in order to improve processability.

[0137] As the rubber softener, mineral oil or a liquid or low-molecular-weight synthetic softener is suitable.

[0138] Mineral oil-based rubber softeners, known as process oils or extender oils, used to soften rubber, increase volume, and improve processability, are mixtures of aromatic, cycloalkane, and paraffin chains. Paraffin chains with carbon atoms accounting for 50% or more of the total carbon atoms are considered paraffinic, naphthenic with 30-45% of the total carbon atoms are considered cycloalkane, and aromatic with aromatic carbon atoms exceeding 30% are considered aromatic. The rubber softeners used in this embodiment are preferably cycloalkane and / or paraffinic.

[0139] The amount of the rubber softener blended per 100 parts by mass of the rubber component containing the modified conjugated diene polymer is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and even more preferably 30 to 90 parts by mass. If the amount of the rubber softener blended per 100 parts by mass of the rubber component exceeds 100 parts by mass, air leakage is likely to occur and ridges may form on the surface of the composition, which is not preferred.

[0140] [Manufacturing of Modified Conjugated Diene Polymer Composition]

[0141] The dynamic storage modulus E′(E) of the rubber composition after vulcanization of the conjugated diene polymer composition of this embodiment, measured under the conditions of a frequency of 10 Hz, a dynamic twist of 3%, and a temperature of 50°C, is in the range of 2 MPa to 10 MPa, and the dynamic storage modulus and the loss tangent tanδ(T) satisfy the following formula (1).

[0142] T≤0.01xE+0.05(1)

[0143] The conjugated diene polymer composition of the present embodiment can be obtained by mixing a rubber component containing a modified conjugated diene polymer and a silicon-based inorganic filler, and optionally, carbon black, other fillers, a silane coupling agent, a rubber softener, and the like.

[0144] The method for mixing the constituent materials of the conjugated diene polymer composition is not particularly limited as long as the above formula (1) is satisfied.

[0145] For example, there can be mentioned a melt kneading method using a general kneading machine such as an open roll, a roll mixer, a Banbury mixer, a toothed mixer, a single-screw extruder, a double-screw extruder, or a multi-screw extruder; a method of dissolving and mixing the components and then heating to remove the solvent; and the like.

[0146] Among them, a dispersive mixing method using a roll mixer or a toothed mixer is preferred. In particular, from the viewpoint of satisfying formula (1), a method in which the constituent materials of the conjugated diene polymer composition of the present embodiment are mixed only once using a roll mixer is preferred. If mixing is performed two or more times, the silicon-based inorganic filler is uniformly dispersed, and although the low hysteresis loss is improved, the dynamic storage modulus (E') is reduced, so it is not preferred.

[0147] [tire]

[0148] The conjugated diene polymer composition of this embodiment can be formed into a tire by vulcanization molding according to conventional techniques. The composition can be used as various tire components, but is preferably used as a tire tread material.

[0149] [Example]

[0150] Hereinafter, the present embodiment will be described in detail with reference to specific examples and comparative examples. However, the present embodiment is not limited to the following examples.

[0151] In addition, the analysis of the polymers of Examples and Comparative Examples was performed by the method described below.

[0152] Molecular weight

[0153] The chromatogram was measured using a GPC (gel permeation chromatography) apparatus connected to three chromatographic columns filled with polystyrene gel, and the molecular weight distribution of the weight average molecular weight (Mw) and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was determined based on a quantitative curve using standard polystyrene.

[0154] The specific measurement conditions are as follows: 20 μL of the following measurement solution was injected into the GPC measurement apparatus for measurement.

[0155] Measurement conditions

[0156] Device: Tosoh Corporation's trade name "HLC-8420GPC"

[0157] Eluent: Tetrahydrofuran (THF)

[0158] Guard column: TSKguardcolumn Super MP, manufactured by Tosoh Corporation

[0159] Separation columns: three connected columns, trade name “TSKgel Super Multipore HZ-M” manufactured by Tosoh Corporation.

[0160] Oven temperature: 40℃

[0161] Flow rate: 0.6mL / min

[0162] Detector: RI detector (trade name "HLC-8420" manufactured by Tosoh Corporation)

[0163] Measurement solution: 20 μL of a measurement solution prepared by dissolving 10 mg of a measurement sample in 20 mL of THF was injected into the GPC measurement apparatus.

[0164] Bonded styrene content

[0165] A conjugated diene polymer was used as a sample, and 100 mg of the sample was mixed with 100 mL of chloroform and dissolved to prepare a measurement sample.

[0166] The amount of bonded styrene (mass %) relative to 100 mass % of the modified conjugated diene polymer sample was measured from the absorbance of styrene at an ultraviolet absorption wavelength (around 254 nm) by the phenyl group (UV spectrophotometer "Agilent Cary 60" manufactured by Agilent Technologies).

[0167] Microstructure of the butadiene portion: 1,2-vinyl bond content

[0168] A modified conjugated diene polymer was used as a sample, and 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare a measurement sample.

[0169] Use solution tube, at 600~1000cm -1 The infrared spectrum was measured over a range of 100 nm and the microstructure of the butadiene portion, i.e., the amount of 1,2-vinyl bonds (mol %), was determined based on the absorbance at a specific frequency using the calculation formula of Hampton's method (described in R.R. Hampton, Analytical Chemistry 21, 923 (1949)) (FTIR spectrophotometer "Agilent Cary 630" manufactured by Agilent Technologies).

[0170] ·Proportion of styrene molecular chains

[0171] The spectrum of a sample obtained by dissolving a conjugated diene polymer in deuterated chloroform was measured using a nuclear magnetic resonance apparatus (1H-NMR) having a proton resonance frequency of 500 MHz. The total integrated values of the chemical shift ranges (A) to (C) described below were calculated, and the ratio of the integrated values in the range (A) was taken as the ratio of molecular chains having eight or more consecutive structural units derived from an aromatic vinyl monomer.

[0172] (A) Aromatic vinyl monomer molecular chain 8 or more: 6.00≤S<6.68

[0173] (B) Aromatic vinyl monomer molecular chain 2 to 7: 6.68 ≤ S < 6.89

[0174] (C) Aromatic vinyl monomer short molecular chain: 6.89≤S≤8.00

[0175] Production Example 1: Conjugated diene polymer (SBR-1)

[0176] An autoclave having an internal volume of 1.5 L and a ratio (L / D) of internal height (L) to diameter (D) of 2.6 and a stirrer and a hood heater was used as a reactor. 800 g of cyclohexane and n-butyl lithium were added to the reactor to neutralize impurities that may interfere with the polymerization reaction in the reactor. After stirring at 70° C. for 5 minutes, the mixture was cooled to room temperature, the solution was removed, and the reactor was emptied.

[0177] Next, after removing impurities in advance, 785 g of cyclohexane, 41 g of styrene, 69 g of 1,3-butadiene, and 0.055 mmol of 2,2-bis(2-oxetanyl)propane as a polar substance were added to the reactor. When the temperature in the reactor reached 60° C., 0.44 mmol of n-butyllithium as a polymerization initiator was added to initiate polymerization.

[0178] Immediately after the polymerization was initiated, the temperature in the reactor rose and reached a peak temperature of 79° C. Immediately thereafter, 0.22 mmol of [3-(dimethylamino)propyl]trimethoxysilane was added as a modifier, and the mixture was stirred for another 3 minutes.

[0179] 1.0 mmol of ethanol was added as a polymerization terminator to terminate the reaction, yielding a polymer solution containing a modified conjugated diene polymer. 0.3 g of 2,6-di-tert-butyl-4-hydroxytoluene was added to the resulting polymer solution as an antioxidant. The solvent was removed by distillation, and the mixture was vacuum-dried to yield a modified conjugated diene polymer (SBR-1). The analytical results of SBR-1 are shown in Table 1.

[0180] Production Example 2: Conjugated diene polymer (SBR-2)

[0181] A modified conjugated diene polymer (SBR-2) was obtained under the same conditions as in Production Example 1 except that 676 g of cyclohexane, 50 g of styrene, and 61 g of 1,3-butadiene were used. The analysis results of SBR-2 are shown in Table 1.

[0182] Production Example 3: Conjugated Diene Polymer (SBR-3)

[0183] A modified conjugated diene polymer (SBR-3) was obtained under the same conditions as in Production Example 1 except that 0.049 mmol of 2,2-bis(2-oxetanyl)propane was used. The analysis results of SBR-3 are shown in Table 1.

[0184] Production Example 4: Conjugated diene polymer (SBR-4)

[0185] A modified conjugated diene polymer (SBR-4) was obtained under the same conditions as in Production Example 1, except that the modifier was changed to bis(trimethoxysilylpropyl)methylamine. The analysis results of SBR-4 are shown in Table 1.

[0186] Production Example 5: Conjugated Diene Polymer (SBR-5)

[0187] A modified conjugated diene polymer (SBR-5) was obtained under the same conditions as in Production Example 1, except that the modifier was changed to 1-methyl-4-[3-(triethoxysilyl)propyl]piperazine. The analysis results of SBR-5 are shown in Table 1.

[0188] Production Example 6: Conjugated Diene Polymer (SBR-6)

[0189] Polymerization was initiated under the same conditions as in Production Example 1. Immediately after polymerization initiation, the temperature within the reactor rose, reaching a peak temperature of 80°C. Immediately thereafter, 1.0 mmol of ethanol was added as a polymerization terminator to terminate the reaction, yielding a polymer solution containing a conjugated diene polymer. A conjugated diene polymer (SBR-6) was obtained under the same conditions as in Production Example 1. The analytical results of SBR-6 are shown in Table 1.

[0190] [Table 1]

[0191]

[0192] Examples 1 to 5 and Comparative Examples 1 to 4

[0193] The raw rubbers (SBR-1 to SBR-6), silicone, a silane coupling agent, process oil, zinc oxide, and stearic acid were kneaded using a Toyo Seiki Seisaku-sho Co., Ltd. internal mixer equipped with a temperature control device as shown in Table 2 under the conditions shown in Table 3. The temperature of the internal mixer was controlled so that the discharge temperature was 155 to 160°C to obtain each rubber composition (compound).

[0194] The obtained rubber composition was put into an internal mixer set at 55° C., sulfur and vulcanization accelerators 1 and 2 were added, and kneading was carried out at a rotor speed of 50 rpm for 10 minutes.

[0195] Thereafter, the sheet was formed into a sheet by an open roll set at 70° C., and the obtained sheet was vulcanized by passing through a vulcanizing press at 160° C. for 20 minutes.

[0196] [Table 2]

[0197] serial number Machine model Inner cavity capacity Rotor shape R60 Labo Plastomill R60 60cc Rotor type (dispersed mixing type) B75 Labo Plastomill B75 75cc Banbury type (distributive mixed type)

[0198] The vulcanized rubber composition was evaluated by the following method. The evaluation results are shown in Table 3.

[0199] Evaluation 1: Viscoelastic parameters

[0200] Viscoelastic parameters were measured in a tensile mode using a dynamic viscoelasticity measuring apparatus "Rheogel-E4000" manufactured by UBM.

[0201] Figure 1 The test results of the dynamic storage modulus and loss function of Examples 1 to 4 and Comparative Examples 1 and 2 in the embodiments of the present invention are shown.

[0202] The dynamic storage modulus (E') measured at 50°C, a frequency of 10 Hz, and a strain of 3% is used as an indicator of steering stability. A larger value indicates better steering stability.

[0203] Tan δ, measured at 50°C, 10 Hz frequency, and 3% strain, is used as an indicator of low hysteresis loss. The smaller the value, the better the low hysteresis loss.

[0204] Tan δ measured at 0°C, 10 Hz frequency, and 1% distortion was used as an index of anti-slip properties. A larger value indicates better anti-slip properties.

[0205] Evaluation 2: Tensile strength and tensile length

[0206] The tensile strength and tensile length were measured in accordance with the tensile test method of JIS K6251, and the result of Comparative Example 5 was set as 100 and indexed.

[0207] The larger the index, the better the tensile strength and tensile length.

[0208] The following materials were used as raw materials.

[0209] Conjugated diene polymers (from SBR-1 to SBR-6)

[0210] Silicon (trade name "Ultrasil 7000GR" manufactured by Ebonic dex) has a nitrogen adsorption specific surface area of 170 m 2 / g)

[0211] Silane coupling agent (trade name "Si75" manufactured by Ebonic dex, bis(triethoxysilylpropyl) disulfide)

[0212] TDAE oil (trade name "VIVATEC 500" manufactured by H&R)

[0213] Zinc oxide (trade name "Zinc Oxide" manufactured by Sakai Chemical Industry Co., Ltd.)

[0214] Stearic acid (trade name "Lunac S-90V" manufactured by Kao Corporation)

[0215] Anti-aging agent (trade name "NOCRAC 6C" produced by Ouchi Shinko Chemical Co., Ltd.)

[0216] Sulfur ("SULFAX 200S" manufactured by Tsurumi Chemical Industries, Ltd.)

[0217] Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazolylsulfonamide, trade name "NOCCELER CZ" manufactured by Ouchi Shinko Chemical Co., Ltd.)

[0218] Vulcanization accelerator 2 (1,3-diphenylguanidine, trade name "NOCCELER D" manufactured by Ouchi Shinko Chemical Co., Ltd.)

[0219] [Table 3]

[0220]

[0221] As shown in the table above, the modified conjugated diene polymer compositions obtained in Examples 1 to 5 have higher storage modulus and lower hysteresis loss (lower loss normal tan δ) than the conjugated diene polymer compositions obtained in Comparative Examples 1 to 5.

[0222] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A modified conjugated diene polymer composition, characterized in that: include: A modified conjugated diene polymer comprising an aromatic vinyl monomer structural unit and a conjugated diene monomer structural unit, wherein the content of the aromatic vinyl monomer structural unit having a molecular chain of 8 or more consecutive aromatic vinyl monomers is less than 10% by mass of the total amount of the aromatic vinyl monomer structural unit; The silicon-based inorganic filler is present in an amount of 60 to 200 parts by mass based on 100 parts by mass of the modified conjugated diene-based polymer.

2. The modified conjugated diene polymer composition according to claim 1, wherein The total amount of the aromatic vinyl monomer structural units is 30% by mass or more relative to the total amount of the modified conjugated diene polymer.

3. The modified conjugated diene polymer composition according to claim 1, wherein The vinyl bond content in the conjugated diene monomer structural unit is 10 mol% or more.

4. The modified conjugated diene polymer composition according to claim 1, wherein The modified conjugated diene polymer has a molecular weight distribution of 1.1 or more.

5. The modified conjugated diene polymer composition according to claim 1, wherein The modified conjugated diene polymer composition further comprises: at least one of carbon black, metal oxide, metal hydroxide, silane coupling agent, vulcanizing agent, vulcanization accelerator and softener.

6. The modified conjugated diene polymer composition according to claim 1, wherein The modified conjugated diene polymer composition after vulcanization was tested under the conditions of a frequency of 10 Hz, a dynamic strain of 3%, and a temperature of 50° C. The modified conjugated diene polymer composition after vulcanization satisfies the following formula (1): T ≤ 0.01×E+0.05…(1) In formula (1), E is the dynamic storage modulus E´, T is the loss tangent tanδ, and E is 2~10 MPa.

7. A method for preparing a modified conjugated diene polymer composition, characterized in that: The following steps are involved: S1: copolymerizing at least one conjugated diene monomer and at least one aromatic vinyl monomer in the presence of alkyl lithium and 2,2-bis(2-oxetanyl)propane to obtain a conjugated diene polymer; S2: modifying the conjugated diene polymer using a modifier to obtain a modified conjugated diene polymer; S3: mixing the modified conjugated diene polymer with the silicon-based inorganic filler to obtain the modified conjugated diene polymer composition, Wherein, the amount of the 2,2-bis(2-oxetanyl)propane used is 0.125 mol relative to 1 mol of lithium in the alkyl lithium; the modifier is selected from [3-(dimethylamino)propyl]triethoxysilane, [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]triethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [2-(dimethylamino)ethyl]triethoxysilane, [2-(dimethylamino)ethyl]trimethoxysilane, and [3-(dimethylamino)propyl]diethoxymethylsilane. One or more selected from the group consisting of [3-dibutylaminopropyl]triethoxysilane, 3-hexamethyleneiminopropyltriethoxysilane, 3-hexamethyleneiminopropyltrimethoxysilane, hexamethyleneiminomethyltrimethoxysilane, hexamethyleneiminomethyltriethoxysilane, 2-hexamethyleneiminoethyltriethoxysilane, 2-hexamethyleneiminoethyltrimethoxysilane, 3-pyrrolidinyloxypropyltriethoxysilane, 3-pyrrolidinyloxypropyltrimethoxysilane, 3-heptamethyleneiminopropyltriethoxysilane, and 3-dodecamethyleneiminopropyltriethoxysilane.

8. The method for preparing the modified conjugated diene polymer composition according to claim 7, wherein: The following steps are involved: In step S3 , the modified conjugated diene polymer and the silicon-based inorganic filler are primarily kneaded using a rubber mixer having a dispersive mixing rotor.

9. A tire, characterized in that: The invention comprises the conjugated diene polymer composition according to any one of claims 1 to 6.

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