Conjugated diene polymer and conjugated diene polymer composition

Abstract

Provided is a conjugated diene polymer in which the content of an aromatic vinyl monomer unit is 35-70% by mass (inclusive), the 1, 2-vinyl bond content in the conjugated diene monomer unit is 21-65% by mole (inclusive), and the average molecular weight of the conjugated diene polymer is 100-300 [mu] m. When the total of (A) + (B) + (C) is 100%, (A) is 0.5% to 25% (inclusive), (B) is 2% to 25% (inclusive), and (C) is 60% to 96.5% (inclusive) with respect to (A) the relative intensity of 6.0 ppm to less than 6.7 ppm, (B) is the relative intensity of 6.7 ppm to less than 6.94 ppm, and (C) is the relative intensity of 6.94 ppm to 7.60 pp (inclusive) in 1H-NMR, and in a molecular weight distribution curve in GPC, the peak top molecular weight of the peak with the largest area is 150,000 to 600,000 (inclusive).

Description

Technical Field

[0001] The present invention relates to a conjugated diene polymer and a conjugated diene polymer composition. Background Art

[0002] Styrene-butadiene rubber (SSBR), produced by solution polymerization, is a conjugated diene polymer composed of butadiene and styrene monomers. SSBR is widely used as a material for various industrial products, including the automotive industry and shoe soles.

[0003] In particular, tires in the automotive industry are increasingly demanding improved performance in rubber materials. For example, increasing the styrene content in conjugated diene polymers can be expected to improve tensile strength at high temperatures, thereby enhancing grip and preventing collapse during high-speed driving. To improve these properties, SSBR with a high styrene content and vinyl bond count is preferably used.

[0004] Furthermore, in order to improve the performance of rubber materials, it is also important to adjust the number of styrene chains in the conjugated diene polymer and control the content of styrene blocks.

[0005] However, there are reports that when the content of the styrene block in the conjugated diene polymer increases, the wear resistance of the rubber material using the conjugated diene polymer deteriorates.

[0006] Note that SSBRs having a high styrene content and a high vinyl bond content and having a controlled number of styrene chains are disclosed in Patent Documents 1 and 2. These documents propose techniques for obtaining SSBRs using metal alkoxides or ethers.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2012 / 119918

[0010] Patent Document 2: International Publication No. 2012 / 175680 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, the SSBR disclosed in Patent Documents 1 and 2 has a problem in that there is still room for improvement in terms of the balance between grip performance, wear resistance, and tensile properties at high temperatures of the tire composition.

[0013] Therefore, an object of the present invention is to provide a conjugated diene polymer that can provide a tire composition having an excellent balance among grip performance, wear resistance, and tensile properties at high temperatures, and also having excellent processability during compound preparation.

[0014] Means for solving problems

[0015] The present inventors have conducted intensive research to address the problems of the prior art described above. As a result, they have discovered that a conjugated diene polymer has excellent processability when prepared as a compound and, when used in tire applications, exhibits an excellent balance among grip performance, wear resistance, and tensile properties at high temperatures. This has led to the completion of the present invention. In this conjugated diene polymer, the content of aromatic vinyl monomer units and the amount of 1,2-vinyl bonds are each within a specified numerical range, the content of blocks formed by linking a specified number of aromatic vinyl monomer units is optimized, the relative intensity based on NMR measurement is within a specified numerical range, and the peak top molecular weight in gel permeation chromatography (GPC) is within a specified range.

[0016] That is, the present invention is as follows. [1]

[0018] A conjugated diene polymer, wherein

[0019] The content of the aromatic vinyl monomer unit is 35% by mass or more and 70% by mass or less,

[0020] The 1,2-vinyl bond content in the conjugated diene monomer unit is 21 mol% or more and 65 mol% or less,

[0021] about 1 In H-NMR, (A) has a relative intensity of 6.0 ppm or more and less than 6.7 ppm, (B) has a relative intensity of 6.7 ppm or more and less than 6.94 ppm, and (C) has a relative intensity of 6.94 ppm or more and 7.60 ppm or less. When the sum of (A) + (B) + (C) is set to 100%, (A) is 0.5% or more and 25% or less, (B) is 2% or more and 25% or less, and (C) is 60% or more and 96.5% or less.

[0022] In a molecular weight distribution curve obtained by gel permeation chromatography (GPC), the peak top molecular weight of the peak with the largest area is 150,000 to 600,000. [2]

[0024] The conjugated diene polymer as described in the above [1], wherein the content of the aromatic vinyl monomer unit is 45% by mass or more and 60% by mass or less. [3]

[0026] The conjugated diene polymer as described in [1] or [2] above, wherein the modification rate is 60% or less. [4]

[0028] The conjugated diene polymer according to any one of the above [1] to [3], wherein the total value of the relative strength of (A) + (B) is 17% to 39%. [5]

[0030] The conjugated diene polymer according to any one of [1] to [4], wherein

[0031] The relative intensity of (A) is 5% or more and 15% or less,

[0032] The relative intensity of (C) is 60% or more and 96% or less. [6]

[0034] The conjugated diene polymer according to any one of [1] to [4], wherein

[0035] The relative intensity of (A) is 0.5% or more and 15% or less,

[0036] The relative intensity of (C) is 60% or more and 96% or less. [7]

[0038] The conjugated diene polymer according to any one of the above-mentioned [1] to [6] is a rubber block molded product. [8]

[0040] A conjugated diene polymer composition comprising the conjugated diene polymer described in any one of [1] to [6] above. [9]

[0042] The conjugated diene polymer composition as described in the above-mentioned [8] is a composition for tires.

[10]

[0044] The conjugated diene polymer composition as described in the above-mentioned [8] is a composition for shoe soles.

[11]

[0046] The conjugated diene polymer composition as described in the above-mentioned [8] is a composition for vibration-proof rubber.

[0047] Effects of the Invention

[0048] According to the present invention, a conjugated diene polymer composition can be provided that has an excellent balance among grip performance, wear resistance, and tensile properties at high temperatures and has excellent processability when preparing a compound. DETAILED DESCRIPTION

[0049] A specific embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail below.

[0050] It should be noted that the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be implemented with various modifications within the scope of the gist thereof.

[0051] [Conjugated diene polymer]

[0052] The conjugated diene polymer of the present embodiment includes a structural unit derived from an aromatic vinyl compound (hereinafter also referred to as “aromatic vinyl monomer unit”) and a structural unit derived from a conjugated diene compound (hereinafter also referred to as “conjugated diene monomer unit”).

[0053] In the conjugated diene polymer of this embodiment,

[0054] The content of the aromatic vinyl monomer unit is 35% by mass or more and 70% by mass or less,

[0055] The 1,2-vinyl bond content in the conjugated diene monomer unit is 21 mol% or more and 65 mol% or less,

[0056] about 1 In H-NMR, (A) relative intensity of 6.0 ppm or more and less than 6.7 ppm, (B) relative intensity of 6.7 ppm or more and less than 6.94 ppm, (C) relative intensity of 6.94 ppm or more and 7.60 ppm or less,

[0057] When the total of (A)+(B)+(C) is 100%,

[0058] (A) 0.5% to 25%

[0059] (B) 2% to 25%

[0060] (C) is 60% or more and 96.5% or less,

[0061] In a molecular weight distribution curve obtained by gel permeation chromatography (GPC), the peak top molecular weight of the peak with the largest area is 150,000 to 600,000.

[0062] According to the above configuration, a conjugated diene polymer composition can be provided that is excellent in the balance among grip performance, wear resistance, and tensile properties at high temperatures, and has excellent processability when preparing a compound.

[0063] Examples of the aromatic vinyl compound include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the perspective of industrial availability.

[0064] These may be used alone or in combination of two or more.

[0065] Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred, from the perspective of ease of industrial availability.

[0066] These may be used alone or in combination of two or more.

[0067] The conjugated diene polymer of the present embodiment may further contain monomer units derived from other monomers in addition to the above-mentioned aromatic vinyl compound and conjugated diene compound.

[0068] Examples of the other monomers include, but are not limited to, acrylonitrile, methyl methacrylate, and methyl acrylate.

[0069] The conjugated diene polymer of the present embodiment is characterized in that the so-called microstructure (content of aromatic vinyl monomer units, amount of 1,2-vinyl bonds, etc.) of the copolymer of a conjugated diene compound and an aromatic vinyl compound is controlled.

[0070] (Content of aromatic vinyl monomer units)

[0071] In the conjugated diene polymer of this embodiment, the content of aromatic vinyl monomer units is 35% by mass or greater, preferably 40% by mass or greater, more preferably 45% by mass or greater, even more preferably exceeding 45% by mass, and even more preferably 46% by mass or greater, from the perspective of grip performance and high-temperature tensile properties of the conjugated diene polymer composition described below (which is a composition formed using the conjugated diene polymer of this embodiment). Furthermore, from the perspective of rubber block moldability, crushability, and wear resistance of the conjugated diene polymer composition, the content of aromatic vinyl monomer units is 70% by mass or less, preferably 68% by mass or less, more preferably 65% ​​by mass or less, even more preferably 63% by mass or less, and even more preferably 60% by mass or less.

[0072] The content of aromatic vinyl monomer units can be determined by 1 The measurement was performed by H-NMR.

[0073] The content of the aromatic vinyl monomer unit can be controlled within the above-mentioned numerical range by adjusting the amount of the aromatic vinyl compound added during polymerization.

[0074] (1,2-vinyl bond amount)

[0075] The 1,2-vinyl bond content in the conjugated diene polymer of this embodiment refers to the molar ratio of the 1,2-vinyl bond content based on the content of the conjugated diene monomer units. From the perspective of grip performance and high-temperature tensile properties in the conjugated diene polymer composition of this embodiment described below, it is 21 mol% or more, preferably 25 mol% or more, more preferably 30 mol% or more, and even more preferably 35 mol% or more. On the other hand, from the perspective of ease of polymerization and resistance to gelation, it is 65 mol% or less, preferably 60 mol% or less, more preferably 58 mol% or less, and even more preferably 55 mol% or less.

[0076] The amount of 1,2-vinyl bonds can be determined by 1 The measurement was performed by H-NMR.

[0077] The amount of 1,2-vinyl bonds can be controlled within the above numerical range by adjusting the reaction starting temperature, reaction ending temperature, and the type and amount of the polar substance added during polymerization.

[0078] When the conjugated diene polymer of the present embodiment is a copolymer composed of butadiene and styrene, the 1,2-vinyl bond amount and the styrene content can be measured by the method described in ISO 21561-2005, specifically, by the method described in the examples below.

[0079] ( 1 Relative intensity in H-NMR measurement)

[0080] In the conjugated diene polymer of this embodiment, 1 When measuring by H-NMR,

[0081] (A) relative intensity of 6.0 ppm or more and less than 6.7 ppm,

[0082] (B) relative intensity of 6.7 ppm or more and less than 6.94 ppm,

[0083] (C) Relative intensity of 6.94 ppm or more and 7.60 ppm or less,

[0084] When the total of (A)+(B)+(C) is 100%, the relative intensities of the respective

[0085] (A) 0.5% to 25%

[0086] (B) 2% to 25%

[0087] (C) is 60% or more and 96.5% or less.

[0088] As a solvent for measurement, for example, a solvent containing 0.05% by mass of TMS (tetramethylsilane) relative to deuterated chloroform can be used.

[0089] The relative intensities reported here refer to the following contents.

[0090] When the conjugated diene polymer of this embodiment is a copolymer composed of butadiene and styrene, the content of block styrene having more than 6 consecutive styrene units can be measured using a relative intensity of 6.0 ppm or more and less than 6.7 ppm according to the method reported by Y. Tanaka et al. in Rubber Chemistry and Technology, 1981, 54, No. 4, 685-691.

[0091] That is, the above (A) is based on 1 The relative intensity of block styrene having more than 6 consecutive styrene units, as determined by H-NMR.

[0092] In addition, the block styrene content having 4 to 6 consecutive styrene units can be measured using a relative intensity of 6.70 ppm or more and less than 6.94 ppm.

[0093] That is, (B) is based on 1 The relative intensity of block styrene having 4 to 6 consecutive styrene units measured by H-NMR.

[0094] In addition, the content of block styrene or random styrene having less than 4 consecutive styrene units can be measured using a relative intensity in the range of 6.94 ppm to 7.60 ppm.

[0095] That is, (C) is based on 1 The relative intensity of block styrene or random styrene having less than 4 consecutive styrene units as determined by H-NMR.

[0096] From the perspective of abrasion resistance of the conjugated diene polymer composition of this embodiment described below, the relative strength of (C) in the conjugated diene polymer of this embodiment is 60% or more, preferably 63% or more, more preferably 65% ​​or more, and even more preferably 70% or more.

[0097] On the other hand, from the perspective of the tensile properties of the conjugated diene polymer composition of this embodiment at high temperatures, it is 96.5% or less, preferably 96% or less, more preferably 95% or less, further preferably 93% or less, further more preferably 90% or less, and further preferably 88% or less.

[0098] In view of the tensile strength of the conjugated diene polymer composition of this embodiment at high temperatures described below, the relative strength of (B) in the conjugated diene polymer of this embodiment is 2% or more, preferably 3% or more, and more preferably 5% or more.

[0099] On the other hand, from the viewpoint of the abrasion resistance of the conjugated diene polymer composition of the present embodiment, it is 25% or less, preferably 23% or less, more preferably 21% or less, and even more preferably 20% or less.

[0100] In addition, from the perspective of the rigidity and handling stability of the conjugated diene polymer composition of this embodiment described later, the relative strength of the above-mentioned (A) in the conjugated diene polymer of this embodiment is 0.5% or more, preferably 1% or more, more preferably 2% or more, further preferably 5% or more, and even more preferably more than 5%.

[0101] On the other hand, from the perspective of the crushability of the rubber block molded body, the wear resistance when the conjugated diene polymer composition described later is prepared, and the fuel consumption performance, it is 25% or less, preferably 20% or less, more preferably 15% or less, further preferably less than 15%, and further more preferably 14% or less.

[0102] From the perspective of the rigidity and tensile properties at high temperatures of the conjugated diene polymer composition according to the present embodiment described below, the total value of the relative strength of (A) and the relative strength of (B) ((A) + (B)) is preferably 17% or more, more preferably 19% or more, and even more preferably 21% or more. Furthermore, from the perspective of the crushability of the gum mass molded article and the abrasion resistance of the conjugated diene polymer composition according to the present embodiment described below, the total value is preferably 39% or less, more preferably 37% or less, and even more preferably 35% or less.

[0103] The relative intensities of (A), (B), and (C) of the conjugated diene polymer of this embodiment can be controlled based on the content of the aromatic vinyl monomer units by adjusting the content of aromatic vinyl monomer units incorporating fewer than four consecutive aromatic vinyl monomer units (the content of aromatic vinyl monomer blocks composed of fewer than four consecutive aromatic vinyl monomer units relative to the total aromatic vinyl monomer used), the content of aromatic vinyl monomer units incorporating four to six consecutive aromatic vinyl monomer units, and the content of aromatic vinyl monomer units incorporating more than six consecutive aromatic vinyl monomer units. Specifically, the relative intensities can be controlled by adjusting the type and amount of the polar substance added during polymerization, the type and amount of the metal alkoxide added, the reaction start temperature, and the reaction end temperature.

[0104] As a polar substance added during polymerization, for example, 2,2-bis(2-tetrahydrofuryl)propane can be used. In this case, the molar ratio relative to the polymerization initiator (polar substance / polymerization initiator) is preferably 0.6 to 1.5, more preferably 0.7 to 1.2, and even more preferably 0.75 to 1.0 mol.

[0105] As the metal alkoxide, for example, sodium amyloxide or potassium tert-amyloxide can be used. In this case, the molar ratio (metal alkoxide / polymerization initiator) relative to the polymerization initiator is preferably 0.01 to 0.60, more preferably 0.02 to 0.40, and even more preferably 0.02 to 0.30.

[0106] Preferably, the more the amount of aromatic vinyl compound added during polymerization, the more the amount of polar substance added is increased, and preferably the polar substance is used in combination with a metal alkoxide. When the above-mentioned polar substance and metal alkoxide are used, by controlling the addition amount within the above-mentioned range, there is a tendency to easily control the relative intensities of the above-mentioned (A), (B), and (C).

[0107] Since the copolymerizability of the conjugated diene compound and the aromatic vinyl compound varies depending on the types of the polar substance and the metal alkoxide, it is preferable to control the amount of these added depending on the types.

[0108] Metal alkoxides tend to have high randomization ability but low vinylization ability. On the other hand, polar substances containing heteroatoms such as nitrogen and oxygen atoms tend to have high vinylization and randomization abilities. The performance differences among polar substances containing nitrogen and oxygen depend on the strength of their interaction with the active ends of the polymer: stronger interactions increase vinylization ability but also increase susceptibility to deactivation. It is preferable to set polymerization conditions based on the preferred addition amounts described above, taking these tendencies into consideration.

[0109] Furthermore, as a polymerization method for the conjugated diene polymer of the present embodiment, an adiabatic polymerization method is preferred but not limited thereto.

[0110] The reaction temperature is preferably a polymerization initiation temperature of 20°C to 45°C, more preferably 22°C to 43°C, and even more preferably 25°C to 42°C. The polymerization termination temperature is preferably 63°C to 63°C, more preferably 65°C to 65°C, even more preferably 68°C to 70°C, and even more preferably 85°C to 85°C, more preferably 83°C to 83°C, and even more preferably 80°C to 80°C.

[0111] By adjusting the polymerization start temperature and polymerization end temperature to the above-mentioned temperature, productivity is practically improved, the random polymerization of the aromatic vinyl monomer unit and the conjugated diene monomer unit can be controlled, and the relative intensities of (A), (B), and (C) can be controlled within an appropriate numerical range.

[0112] In order to improve the relative strength of the above-mentioned (A), it is effective to use a portion of the entire aromatic vinyl compound used in the polymerization to produce the aromatic vinyl monomer block. After the aromatic vinyl monomer block is initially polymerized in the polymerization, the conjugated diene compound and the aromatic vinyl compound may be copolymerized, or the aromatic vinyl monomer block may be polymerized after the conjugated diene compound and the aromatic vinyl compound are copolymerized.

[0113] To improve the relative strength of (B), for example, it is effective to perform polymerization with a high concentration of the aromatic vinyl compound when copolymerizing the aromatic vinyl compound and the conjugated diene compound, use a polar substance with low randomizing ability, and reduce the added amount.

[0114] In order to improve the relative strength of (C), for example, it is effective to increase the randomness of the aromatic vinyl monomer unit and the conjugated diene monomer unit, increase the amount of polar substance added, and lower the reaction temperature.

[0115] (weight average molecular weight)

[0116] In the conjugated diene polymer of this embodiment, the weight average molecular weight is preferably 150,000 or more, more preferably 200,000 or more, and even more preferably 230,000 or more, from the perspective of reducing adhesion during production and the tensile properties of the conjugated diene polymer composition of this embodiment described below.

[0117] On the other hand, from the viewpoint of processability, it is preferably 1.2 million or less, more preferably 1 million or less, further preferably 800,000 or less, and even more preferably 600,000 or less.

[0118] In the conjugated diene polymer of this embodiment, the molecular weight distribution is preferably 1.02 or greater, more preferably 1.03 or greater, and even more preferably 1.05 or greater, from the perspective of processability. On the other hand, from the perspective of the balance between fuel efficiency and grip performance of the conjugated diene polymer composition of this embodiment described below, the molecular weight distribution is preferably 2.5 or less, more preferably 2.0 or less, even more preferably 1.8 or less, and even more preferably 1.5 or less.

[0119] From the perspective of handling stability when the conjugated diene polymer of the present embodiment is used as a tire material, when the conjugated diene polymer of the present embodiment is measured by gel permeation chromatography (GPC), the peak top molecular weight of the peak with the largest area is 150,000 or more, preferably 170,000 or more, more preferably 200,000 or more, and even more preferably 220,000 or more. On the other hand, from the perspective of processability, the molecular weight is 600,000 or less, preferably 550,000 or less, more preferably 500,000 or less, even more preferably 450,000 or less, and even more preferably 360,000 or less.

[0120] The weight average molecular weight, molecular weight distribution, and peak top molecular weight of the largest peak of the conjugated diene polymer of the present embodiment can be measured by gel permeation chromatography (GPC), specifically, by the method described in the examples below.

[0121] Regarding the peak with the largest area, when there are two or more peaks, if the areas are the same, the peak top molecular weight of the peak with the smaller molecular weight is selected.

[0122] The peak top molecular weight refers to the molecular weight at a point where the slope is 0 when the molecular weight distribution curve of the peak is differentiated.

[0123] The peak top molecular weight of the peak with the largest area when the conjugated diene polymer of the present embodiment is measured by GPC can be controlled within the above numerical range by adjusting the amount of the polymerization initiator or the coupling agent described below.

[0124] (coupling)

[0125] The conjugated diene polymer of the present embodiment may be obtained by coupling the active ends of the conjugated diene polymer obtained through the polymerization step using a bifunctional or higher-functional reactive compound (hereinafter also referred to as a "coupling agent") .

[0126] In the coupling reaction step, a coupling reaction is performed on one of the active terminals of the conjugated diene polymer using a coupling agent to obtain the conjugated diene polymer.

[0127] Examples of coupling agents include, but are not limited to, coupling agents having one or more functional groups such as epoxy groups, carbonyl groups, carboxylate groups, carboxamide groups, anhydride groups, phosphate groups, phosphite groups, epithio groups, thiocarbonyl groups, thiocarboxylate groups, dithiocarboxylate groups, thiocarboxamide groups, imino groups, ethyleneimine groups, halogen groups, alkoxysilyl groups, isocyanate groups, thioisocyanate groups, conjugated diene groups, and arylvinyl groups. Among coupling agents, coupling agents containing nitrogen atoms can also be used as the modifiers described below.

[0128] The coupling agent may include, but is not limited to, halogenated silane compounds such as silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethylsilicon trichloride, monoethylsilicon trichloride, monobutylsilicon trichloride, monohexylsilicon trichloride, monomethylsilicon tribromide, and bis(trichlorosilyl)ethane; and alkoxyhalogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane.

[0129] Other examples include, but are not limited to, alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and alkyltriphenoxysilane; and compounds having an imino group and an alkoxysilyl group, such as tris(trimethoxysilyl)propylamine, triethoxysilylpropylamine, N-(1,3-dimethylbutylene)-3-(triethoxysilyl)-1-propylamine, N-(1,3-dimethylbutylene)-3-(tributoxysilyl)-1-propylamine, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propylamine, N-ethylene-3-(triethoxysilyl)-1-propylamine, and N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole.

[0130] Further examples include, but are not limited to, 2-[3-(trimethoxysilyl)propyl]-1,3-dimethylimidazoline, 2-[3-(trimethoxysilyl)propyl]-1,3-(bistrimethylsilyl)imidazoline, 2-(diethoxydiethylsilyl)-1,3-diethylimidazoline, 2-(triethoxysilyl)-1,4-diethylpiperazine, 2-(dimethoxymethylsilyl)-1,4-dimethylpiperazine, 5-(triethoxysilyl)-1,3-dipropylhexahydropyrimidine, 5-(diethoxyethylsilyl)-1,3- Diethylhexahydropyrimidine, {2-[3-(2-dimethylaminoethyl)-2-(ethyldimethoxysilyl)-imidazolin-1-yl]-ethyl}-dimethylamine, 5-(trimethoxysilyl)-1,3-bis-(2-methoxyethyl)-hexahydropyrimidine, 5-(ethyldimethoxysilyl)-1,3-bis-(2-trimethylsilylethyl)-hexahydropyrimidinyl-1,3-dimethylimidazoline, 2-(3-diethoxyethylsilyl-propyl)-1,3-diethylimidazoline, 2-(3-triethoxysilyl-propyl)-1,4-diethyl Piperazine, 2-(3-dimethoxymethylsilyl-propyl)-1,4-dimethylpiperazine, 5-(3-triethoxysilyl-propyl)-1,3-dipropylhexahydropyrimidine, 5-(3-diethoxyethylsilyl-propyl)-1,3-diethylhexahydropyrimidine, {2-[3-(2-dimethylaminoethyl)-2-(3-ethyldimethoxysilyl-propyl)-imidazolin-1-yl]-ethyl}-dimethylamine, 5-(3-trimethoxysilyl-propyl)-1,3-bis-(2-methoxyethyl)-hexahydropyrimidine, 5-(3-ethyldimethoxy Silyl-propyl)-1,3-bis-(2-trimethylsilylethyl)-hexahydropyrimidine, 2-[3-(trimethoxysilyl)propyl]-1,3-bis(trimethylsilyl)imidazoline, 2-(diethoxyethylsilyl)-1,3-bis(triethylsilyl)imidazoline, 2-(triethoxysilyl)-1,4-bis(trimethylsilyl)piperazine, 2-(dimethoxymethylsilyl)-1,4-bis(trimethylsilyl)piperazine, 5-(triethoxysilyl)-1,3-bis(tripropylsilyl)hexahydropyrimidine, and the like.

[0131] Further examples include, but are not limited to, [3-(1-hexamethyleneimino)propyl]triethoxysilane, [3-(1-hexamethyleneimino)propyl]trimethoxysilane, [2-(1-hexamethyleneimino)ethyl]triethoxysilane, [2-(1-hexamethyleneimino)ethyl]trimethoxysilane, [3-(1-pyrrolidinyl)propyl]triethoxysilane, [3-(1-pyrrolidinyl)propyl]trimethoxysilane, [3-(1-heptamethyleneimino)propyl]triethoxysilane, [3-(1-dodecano ... [3-(1-hexamethyleneimino)propyl]diethoxymethylsilane, [3-(1-hexamethyleneimino)propyl]diethoxyethylsilane, N-[3-(triethoxysilyl)-propyl]-N,N'-diethyl-N'-trimethylsilyl-ethane-1,2-diamine, N-[2-(trimethoxysilyl)-ethyl]-N,N',N'-trimethylethane-1,2-diamine, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, and the like.

[0132] Other examples include, but are not limited to, tetraglycidyl-m-phenylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane, etc. Further examples include, but are not limited to, isocyanate compounds such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, diphenylethane diisocyanate, and 1,3,5-phenylene triisocyanate.

[0133] Other examples include, but are not limited to, 3-(4-methylpiperazin-1-yl)propyltriethoxysilane, 1-[3-(diethoxyethylsilyl)propyl]-4-methylpiperazine, 1-[3-(trimethoxysilyl)propyl]-3-methylimidazoline, 1-[3-(diethoxysilyl)propyl]-3-ethylimidazoline, 1-[3-(triethoxysilyl)propyl]-3-methylhexahydropyrimidine, 1-[3-(dimethoxysilyl)propyl]-3-ethylimidazoline, 3-[3-(trimethylsilyl)propyl]-1-methyl-1,2,3,4-tetrahydropyrimidine, 3-[3-(dimethoxymethylsilyl)propyl]-1-ethyl-1,2,3,4-tetrahydropyrimidine, 1-(2-ethoxyethyl)-3-[3-(trimethoxysilyl)propyl]imidazoline, (2-{3-[3-(trimethylsilyl)propyl]tetrahydropyrimidine 1-[3-(triethoxysilyl)propyl]-4-(trimethylsilyl)piperazine, 1-[3-(dimethoxymethylsilyl)propyl]-4-(trimethylsilyl)piperazine, 1-[3-(tributoxysilyl)propyl]-4-(trimethylsilyl)piperazine, 1-[3-(diethoxyethylsilyl)propyl]-3-(triethylsilyl)imidazoline, 2-(trimethoxy hexahydropyrimidine, 1-[3-(triethoxysilyl)propyl]-3-(trimethylsilyl)hexahydropyrimidine, 1-[4-(triethoxysilyl)propyl]-4-(trimethylsilyl)piperazine, and the like.

[0134] (modified)

[0135] The conjugated diene polymer of this embodiment may be a modified polymer.

[0136] In addition, in this specification, modification of a conjugated diene polymer with a nitrogen-containing compound is referred to as modification.

[0137] The modification method is not particularly limited, and examples thereof include a method using a polymerization initiator comprising a nitrogen-containing compound, a method using a nitrogen-containing compound as a polymerization monomer, a method using the above-mentioned coupling agent containing a nitrogen atom, a method of reacting a non-coupling nitrogen-containing compound with a reaction-terminating terminal, and a method of modifying the double bonds of a polymerized conjugated diene polymer by reacting with a nitrogen-containing compound.

[0138] Examples of the polymerization initiator comprising a nitrogen-containing compound include, but are not limited to, reaction products of nitrogen-containing compounds such as dimethylamine, diethylamine, dibutylamine, dipropylamine, diheptylamine, dihexylamine, dioctylamine, di(2-ethylhexyl)amine, didecylamine, ethylpropylamine, ethylbutylamine, ethylbenzylamine, methylphenethylamine, piperidine, hexamethyleneimine, azacyclooctane, 1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, 1,2,3,6-tetrahydropyridine, and 3,5-dimethylpiperidine with organic lithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, n-propyllithium, and isopropyllithium.

[0139] In addition, examples of non-coupling nitrogen-containing compounds include, but are not limited to, 1,3-diethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-propyl-2-imidazolidinone, 1-methyl-3-butyl-2-imidazolidinone, and 1,3-dihydro-1,3-dimethyl-2H-imidazol-2-one.

[0140] (Modification rate)

[0141] In this specification, unless otherwise specified, the “modification ratio” refers to the mass ratio of the polymer having a nitrogen atom-containing functional group relative to the total amount of the conjugated diene polymer of the present embodiment.

[0142] For example, when a nitrogen-containing modifier reacts with the terminal of a polymer before modification, the mass ratio of the polymer having a nitrogen-containing functional group generated by the nitrogen-containing modifier to the total amount of the conjugated diene polymer is expressed as the modification rate.

[0143] As described above, coupling agents containing nitrogen atoms are also included in modifying agents containing nitrogen atoms.

[0144] On the other hand, when a polymer is branched using a branching agent containing nitrogen atoms, the resulting branched polymer also has nitrogen-containing functional groups. Therefore, the branched polymer is also included as a polymer having nitrogen-containing functional groups when calculating the modification rate.

[0145] That is, in this specification, the polymer having a nitrogen atom-containing functional group is a polymer having a nitrogen atom-containing functional group produced using a nitrogen atom-containing modifier and a branched polymer produced using a branching agent having a nitrogen atom-containing functional group, and the total mass ratio of these is the "modification ratio".

[0146] In the conjugated diene polymer of the present embodiment, from the perspective of balancing the processability, abrasion resistance, and tensile properties at high temperatures of the conjugated diene polymer composition of the present embodiment described later, the modification rate measured by the column adsorption GPC method (hereinafter also referred to as "modification rate") is preferably 60% or less relative to the total amount of the conjugated diene polymer.

[0147] From the perspective of improving the wear resistance of the conjugated diene polymer composition of this embodiment, the modification rate is preferably 20% or greater, more preferably 30% or greater. On the other hand, from the perspective of processability and tensile properties at high temperatures, the modification rate is preferably 60% or less, more preferably 30% or less, and even more preferably 20% or less. The polymer may be unmodified.

[0148] The modification rate of the conjugated diene polymer of the present embodiment can be measured by, for example, chromatography that can separate a modified component having a nitrogen-containing functional group from an unmodified component not having the nitrogen-containing functional group.

[0149] Examples of methods using this chromatography include a method using a gel permeation chromatography column filled with a polar material such as silicon oxide that adsorbs nitrogen-containing functional groups and performing quantitative determination by comparison with an internal standard of a non-adsorbed component (column adsorption GPC method).

[0150] More specifically, the modification rate can be determined by measuring the amount of adsorption on the silica column based on the difference between the chromatogram obtained by measuring a sample solution containing the sample and a low molecular weight internal standard polystyrene using a polystyrene gel column and the chromatogram obtained by measuring using a silica column, thereby determining the modification rate.

[0151] More specifically, the modification rate can be measured by the method described in Examples below.

[0152] The modification rate of the conjugated diene polymer of the present embodiment can be controlled within the above numerical range by, for example, adjusting the amount of the modifier added and the reaction method.

[0153] [Method for producing conjugated diene polymer]

[0154] The conjugated diene polymer of this embodiment is obtained by performing a polymerization step, which is a step of polymerizing an aromatic vinyl compound and a conjugated diene compound using a predetermined polymerization initiator. A coupling reaction step and / or a modification reaction step may be further performed using the aforementioned coupling agent and modifier, followed by a hydrogenation step. A branching step may be performed using a branching agent prior to the aforementioned coupling reaction step and modification step.

[0155] (Polymerization process)

[0156] As the polymerization initiator used in the polymerization step, for example, an organic monolithium compound can be used.

[0157] Examples of the organic monolithium compound include, but are not limited to, low-molecular-weight organic monolithium compounds and solubilized oligomeric organic monolithium compounds.

[0158] As the organic monolithium compound, regarding the bonding form of the organic group and lithium, compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond can be used, but are not limited thereto.

[0159] The amount of the organic monolithium compound used as a polymerization initiator is preferably determined according to the structure of the desired conjugated diene polymer and the molecular weight of the conjugated diene polymer.

[0160] The amount of monomers such as conjugated diene compounds used relative to the amount of polymerization initiator used affects the degree of polymerization, that is, tends to affect the number average molecular weight and / or weight average molecular weight, and peak top molecular weight of the conjugated diene polymer.

[0161] Therefore, in order to increase the molecular weight of the conjugated diene polymer of this embodiment, the amount of the polymerization initiator used can be adjusted to be reduced, and in order to decrease the molecular weight, the amount of the polymerization initiator used can be adjusted to be increased.

[0162] As the organic monolithium compound, an alkyllithium compound having a substituted amino group or lithium dialkylamide is preferred because it is used as one of the methods for introducing nitrogen atoms into a conjugated diene polymer.

[0163] In this case, a conjugated diene polymer having a nitrogen atom constituting an amino group at the polymerization initiation terminal can be obtained.

[0164] The substituted amino group is an amino group having no active hydrogen or a structure in which the active hydrogen is protected.

[0165] Examples of the alkyllithium compound having an amino group without active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0166] Examples of the alkyllithium compound having an amino group with protected active hydrogen include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0167] Examples of the lithium dialkylamide include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidine, lithium piperidine, lithium heptamethyleneimide, lithium morpholine, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0168] These organic monolithium compounds having a substituted amino group can also be used as organic monolithium compounds that are soluble oligomers by reacting with a small amount of a polymerizable monomer such as 1,3-butadiene, isoprene, or styrene.

[0169] From the perspective of industrial availability and ease of polymerization reaction control, the organic monolithium compound as the polymerization initiator is preferably an alkyllithium compound. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal can be obtained.

[0170] Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.

[0171] As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferred from the viewpoint of ease of industrial availability and ease of control of the polymerization reaction.

[0172] The above-mentioned organic monolithium compounds may be used alone or in combination of two or more. In addition, the polymerization initiator may be used in combination with other organic metal compounds.

[0173] Examples of the other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0174] Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds, as well as alkoxides, sulfonates, carbonates, and amide compounds of alkaline earth metals.

[0175] Examples of the organomagnesium compound include dibutylmagnesium and ethylbutylmagnesium.

[0176] Examples of other organometallic compounds include organoaluminum compounds.

[0177] Examples of the polymerization reaction mode in the polymerization step include, but are not limited to, batch-wise (also referred to as "batch-wise") and continuous polymerization reaction modes.

[0178] In a continuous process, one or more connected reactors can be used. A continuous reactor, for example, a tank-type or tubular reactor with a stirrer can be used. In a continuous process, preferably, monomers, an inert solvent, and a polymerization initiator are continuously loaded into the reactor, a polymer solution containing the conjugated diene polymer is obtained in the reactor, and the conjugated diene polymer solution is continuously discharged.

[0179] A batch reactor, for example, a tank reactor equipped with a stirrer is used. In the batch reactor, monomers, an inert solvent, and a polymerization initiator are preferably loaded, and monomers are added continuously or intermittently during polymerization as needed to obtain a polymer solution containing the conjugated diene polymer in the reactor. After the polymerization is completed, the conjugated diene polymer solution is discharged.

[0180] In the method for producing the conjugated diene polymer of the present embodiment, a continuous method is preferred in which the conjugated diene polymer can be continuously discharged and supplied to the next reaction in a short time in order to obtain a conjugated diene polymer having an active terminal at a high ratio.

[0181] In the polymerization step of the conjugated diene polymer of this embodiment, the polymerization is preferably carried out in an inert solvent. Examples of the inert solvent include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and mixtures thereof.

[0182] Treatment of allenes and acetylenes as impurities with an organometallic compound before the polymerization reaction tends to yield a conjugated diene polymer having a high concentration of active terminals and a high modification rate, which is preferred.

[0183] During the polymerization step, a polar substance may be added. This allows for random copolymerization of the aromatic vinyl compound and the conjugated diene compound. Polar substances can also serve as vinylating agents to control the microstructure of the conjugated diene moiety. They also tend to be effective in promoting the polymerization reaction.

[0184] Polar substances include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis(2-tetrahydrofuryl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidylethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alcoholate compounds such as potassium tert-amylate, potassium tert-butoxide, sodium tert-butoxide, and sodium amylate; and phosphine compounds such as triphenylphosphine.

[0185] These polar substances may be used alone or in combination of two or more.

[0186] The amount of the polar substance used is not particularly limited and may be selected depending on the intended purpose, but is preferably from 0.01 mol to 10 mol per 1 mol of the polymerization initiator.

[0187] When such polar substances are used as vinylating agents, they can be used in appropriate amounts depending on the desired 1,2-vinyl bond content, acting as modifiers for the microstructure of the conjugated diene portion of the conjugated diene polymer. Many polar substances also exhibit an effective randomizing effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and can be used as modifiers for the distribution of aromatic vinyl compounds or for adjusting the amount of aromatic vinyl monomer blocks.

[0188] As a method for randomizing a conjugated diene compound and an aromatic vinyl compound, for example, as described in JP-A-59-140211, a copolymerization reaction is initiated with the total amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene is intermittently added during the copolymerization reaction.

[0189] The polymerization temperature in the polymerization step is preferably a temperature at which living anionic polymerization is carried out. From the perspective of productivity, the polymerization temperature is more preferably 0°C or higher, further preferably 120°C or lower, and even more preferably 30°C or higher and 100°C or lower. By keeping the polymerization temperature within this range, a sufficient amount of the modifier reacting with the active terminals after completion of polymerization tends to be ensured.

[0190] (Coupling process, modification process, hydrogenation process)

[0191] The active ends of the conjugated diene polymer obtained by the above-mentioned polymerization step and, if necessary, the branching step using a specified branching agent can be subjected to the above-mentioned coupling reaction based on the coupling agent and the modification reaction based on the modifier containing a nitrogen atom. When a coupling agent containing a nitrogen atom is used, the coupling reaction and the modification reaction are carried out simultaneously. In addition, a hydrogenation step can be appropriately carried out to carry out the hydrogenation reaction.

[0192] (Deactivator Addition Step, Neutralizer Addition Step)

[0193] In the method for producing the conjugated diene polymer of the present embodiment, a deactivating agent, a neutralizing agent, and the like may be added to the polymer solution as needed.

[0194] Examples of the deactivating agent include, but are not limited to, water; alcohols such as methanol, ethanol, and isopropanol; and the like.

[0195] Examples of the neutralizing agent include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and neodecanoic acid (a mixture of multibranched carboxylic acids having 9 to 11 carbon atoms, with 10 being the core); aqueous solutions of inorganic acids; and carbon dioxide.

[0196] (Rubber stabilizer)

[0197] In the method for producing the conjugated diene polymer of the present embodiment, it is preferred to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing.

[0198] As the rubber stabilizer, known rubber stabilizers may be used, but are not limited thereto. Examples include antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl 3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0199] (Desolventization process)

[0200] In the method for producing the conjugated diene polymer of the present embodiment, a known method can be used to obtain the obtained conjugated diene polymer from the polymer solution. Examples of such methods include, but are not limited to, methods in which the solvent is separated by steam stripping, the polymer is filtered out, and the polymer is further dehydrated and dried to obtain the polymer; methods in which the polymer is concentrated using a flash tank and then devolatilized using a degassing extruder; and methods in which the polymer is directly devolatilized using a rotary drum dryer.

[0201] [Conjugated diene polymer composition]

[0202] The conjugated diene polymer composition of the present embodiment contains the conjugated diene polymer of the present embodiment described above.

[0203] The conjugated diene polymer composition of the present embodiment preferably contains 10 parts by mass or more, and more preferably 15 parts by mass or more, of filler per 100 parts by mass of the conjugated diene polymer of the present embodiment. On the other hand, from the perspective of fully dispersing the filler and ensuring that the processability and mechanical strength of the conjugated diene polymer composition of the present embodiment are practically sufficient, the filler content is preferably 250 parts by mass or less, more preferably 200 parts by mass or less, and even more preferably 150 parts by mass or less, per 100 parts by mass of the conjugated diene polymer of the present embodiment.

[0204] (filler)

[0205] Examples of fillers include, but are not limited to, silicon oxide-based inorganic fillers, carbon black, calcium carbonate, titanium oxide, aluminum hydroxide, clay, etc. These fillers may be used alone or in combination of two or more.

[0206] In addition, other fillers may be further contained.

[0207] As the silica-based inorganic filler, known silica-based inorganic fillers can be used, but are not limited thereto. For example, solid particles containing SiO2 or Si3Al as a structural unit are preferred, and solid particles containing SiO2 or Si3Al as a main component of the structural unit are more preferred. Here, the main component refers to a component comprising 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more of the silica-based inorganic filler.

[0208] Specific examples of the silica-based inorganic filler include, but are not limited to, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber.

[0209] Furthermore, as the silica-based inorganic filler, a silica-based inorganic filler whose surface has been hydrophobized, or a mixture of a silica-based inorganic filler and an inorganic filler other than silica-based fillers can be used.

[0210] Among these, from the perspective of the strength and wear resistance of the conjugated diene polymer composition of this embodiment, silica and glass fiber are preferred as silica-based inorganic fillers, and silica is more preferred. Examples of silica include dry silica, wet silica, and synthetic silicate silica.

[0211] Examples of carbon black include, but are not limited to, various grades of carbon black such as SRF, FEF, HAF, ISAF, and SAF. Among these, a carbon black having a nitrogen adsorption specific surface area of ​​50 m 2 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less.

[0212] In the conjugated diene polymer composition of the present embodiment, the carbon black content is preferably from 5 parts by mass to 150 parts by mass, more preferably from 10 parts by mass to 120 parts by mass, and even more preferably from 15 parts by mass to 100 parts by mass, relative to 100 parts by mass of the conjugated diene polymer of the present embodiment. By being within the above ranges, the conjugated diene polymer composition of the present embodiment tends to have excellent breaking strength, compression set, and hardness.

[0213] Preferred examples of calcium carbonate include, but are not limited to, calcium carbonate having an average particle size of 0.04 μm to 8.0 μm and an oil absorption of 10 to 35 g per 100 g of calcium carbonate.

[0214] The conjugated diene polymer composition of the present embodiment may contain fillers other than the various fillers described above. Examples of the other fillers include metal oxides and metal hydroxides.

[0215] Metal oxides are those with the chemical formula: M x O y (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) solid particles as a main component of the structural unit.

[0216] Examples of the metal oxide include, but are not limited to, aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide.

[0217] Examples of the metal hydroxide include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0218] (Silane coupling agent)

[0219] The conjugated diene polymer composition of this embodiment may contain a silane coupling agent.

[0220] The silane coupling agent has a function of strengthening the interaction between the conjugated diene polymer and the filler.

[0221] The silane coupling agent is preferably a compound having groups having affinity or bonding properties for the conjugated diene polymer and the silica inorganic filler, respectively, and having a sulfur bonding portion and an alkoxysilyl group or silanol group portion in one molecule.

[0222] Examples of such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0223] In the conjugated diene polymer composition of this embodiment, the content of the silane coupling agent is preferably from 0.1 to 30 parts by mass, more preferably from 0.5 to 20 parts by mass, and even more preferably from 1.0 to 15 parts by mass, relative to 100 parts by mass of the filler. When the content of the silane coupling agent is within the above range, the above-mentioned effect of the addition of the silane coupling agent tends to be more pronounced.

[0224] (Rubber softener)

[0225] The conjugated diene polymer composition of the present embodiment may contain a rubber softener as needed.

[0226] The rubber softener may be pre-incorporated into the conjugated diene polymer or added to the conjugated diene polymer composition. Addition of the rubber softener is preferred from the perspectives of improving the aggregation of the conjugated diene polymer, suppressing the generation of powder, thereby increasing the productivity of the conjugated diene polymer, and further improving the processability of the conjugated diene polymer composition after compounding with a filler.

[0227] Examples of the rubber softener include, but are not limited to, extender oil, liquid rubber, and resin.

[0228] As a method for adding a rubber softener to the conjugated diene polymer constituting the conjugated diene polymer composition, the following method can be cited as a preferred method but is not limited thereto: adding the rubber softener to a conjugated diene polymer solution, mixing to prepare a polymer solution containing the rubber softener, and desolvating the resulting solution.

[0229] Examples of the extender oil include, but are not limited to, aromatic oils, cycloparaffin oils, and paraffin oils. Among these, preferred are alternative aromatic oils having a polycyclic aromatic (PCA) content of 3% by mass or less based on the IP346 method, from the perspectives of environmental safety, oil bleed prevention, and wet grip properties. Examples of alternative aromatic oils include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as described in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999).

[0230] Examples of the liquid rubber include, but are not limited to, liquid polybutadiene and liquid styrene-butadiene rubber.

[0231] Effects of adding liquid rubber include, in addition to improving the processability of a conjugated diene polymer composition containing a conjugated diene polymer and a filler, improving the wear resistance and low-temperature properties of the vulcanizate by shifting the glass transition temperature of the conjugated diene polymer composition toward lower temperatures.

[0232] Examples of the resin include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resin), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, oligomers of monoolefins, oligomers of diolefins, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated aliphatic hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oleoresins, and esters of hydrogenated oleoresins with monofunctional or polyfunctional alcohols.

[0233] These resins may be used alone or in combination of two or more. When hydrogenation is performed, all the unsaturated groups may be hydrogen or some may remain.

[0234] Examples of the effects of adding the resin include an effect of improving the processability of a conjugated diene polymer composition obtained by mixing the conjugated diene polymer of this embodiment with a filler, and an effect of improving the breaking strength of a sulfide. Furthermore, an effect of improving the tensile properties at high temperatures by shifting the glass transition temperature of the conjugated diene polymer composition of this embodiment toward the high temperature side can be cited.

[0235] The amount of the rubber softener, extender oil, liquid rubber, or resin added is preferably from 1 part by mass to 60 parts by mass, more preferably from 5 parts by mass to 50 parts by mass, and even more preferably from 10 parts by mass to 37.5 parts by mass, relative to 100 parts by mass of the conjugated diene polymer of this embodiment.

[0236] When the rubber softener is added within the above range, the conjugated diene polymer composition obtained by mixing the conjugated diene polymer of this embodiment with a filler and the like tends to have good processability and good breaking strength and wear resistance after being converted into a vulcanizate.

[0237] (Other additives)

[0238] The conjugated diene polymer composition of this embodiment may contain various additives such as other softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, lubricants, and tackifiers in addition to the above-mentioned additives within a range that does not impair the purpose of this embodiment.

[0239] As other softeners, known softeners can be used.

[0240] The other fillers are not particularly limited, and examples thereof include magnesium carbonate, aluminum sulfate, and barium sulfate. As the heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant, known materials can be used.

[0241] (Method for producing conjugated diene polymer composition)

[0242] The conjugated diene polymer composition of the present embodiment can be produced by mixing the above-mentioned filler, silane coupling agent, rubber softener, other additives, and the like with the conjugated diene polymer of the present embodiment as needed.

[0243] Examples of the mixing method include, but are not limited to, a melt kneading method using a conventional mixer such as an open roll mill, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder; a method in which the components are dissolved and mixed and then heated to remove the solvent; and the like.

[0244] Among these, the melt kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferred from the perspective of productivity and good kneading properties. In addition, a method of kneading the conjugated diene polymer of the present embodiment with a filler, a silane coupling agent, and additives all at once or a method of mixing them in multiple batches can be applied.

[0245] [Rubber block molding]

[0246] The conjugated diene polymer of this embodiment can be made into a rubber block molded product.

[0247] The rubber block molded body refers to a block of a conjugated diene polymer obtained by compression molding, and can be obtained, for example, by extruding the conjugated diene polymer using an extruder, cutting the pellets, and compression molding the pellets to obtain the molded body.

[0248] [Vulcanized composition]

[0249] The conjugated diene polymer composition of the present embodiment can be made into a vulcanized composition by vulcanization treatment with a vulcanizing agent.

[0250] Examples of the vulcanizing agent include, but are not limited to, free radical initiators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur-containing compounds.

[0251] Sulfur-containing compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfide compounds, etc.

[0252] The content of the vulcanizing agent in the vulcanized composition of the present embodiment is preferably from 0.01 to 20 parts by mass, more preferably from 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component comprising the conjugated diene polymer of the present embodiment. Conventionally known methods can be used as the vulcanization method, and the vulcanization temperature is preferably from 120°C to 200°C, more preferably from 140°C to 180°C.

[0253] During vulcanization, a vulcanization accelerator may be used as needed.

[0254] As the vulcanization accelerator, conventionally known materials can be used, and examples thereof include, but are not limited to, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, examples of vulcanization aids include, but are not limited to, zinc white, stearic acid, and triallyl isocyanurate.

[0255] The content of the vulcanization accelerator is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component containing the conjugated diene polymer of this embodiment.

[0256] Examples of organic peroxides include, but are not limited to, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexene-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,2'-bis(tert-butylperoxy)-p-isopropylbenzene, dicumyl peroxide, di-tert-butylperoxy Oxide, tert-butyl peroxide, peroxy terpene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butyl perbenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy)perbenzoate, 4,4-bis(tert-butylperoxy)valerate, tert-butyl peroxyisopropyl carbonate, etc.

[0257] Examples of the conjugated diene polymer composition of the present embodiment include compositions for tires, compositions for shoe soles, compositions for vibration-proof rubbers, rubber compositions for vibration damping materials, rubber compositions for rubber belts, and compositions for automobile interiors.

[0258] Example

[0259] The present embodiment will be described in further detail below with reference to specific examples, comparative examples, application examples, and application comparative examples. However, the present embodiment is not limited to the following examples, comparative examples, application examples, and application comparative examples.

[0260] Here, specific examples of the conjugated diene polymer are referred to as “Examples” and “Comparative Examples”, and specific examples of the conjugated diene polymer composition are referred to as “Application Examples” and “Comparative Application Examples”.

[0261] In addition, various physical properties in Examples and Comparative Examples, Application Examples, and Application Comparative Examples were measured by the methods shown below.

[0262] [Physical property measurement method]

[0263] [Top molecular weight of the peak with the largest area in the molecular weight distribution curve of GPC]

[0264] The chromatogram was measured using a GPC measuring apparatus connected to three columns using polystyrene-based gel as a filler, and the peak top molecular weight of the peak with the largest area was determined based on a calibration curve obtained using standard polystyrene.

[0265] Specific measurement conditions are as follows.

[0266] 20 μL of the following measurement solution was injected into the GPC measurement apparatus for measurement.

[0267] (Measurement conditions)

[0268] Device: HLC-8320GPC, manufactured by Tosoh Corporation

[0269] Eluent: Tetrahydrofuran (THF) with 5 mmol / L triethylamine added

[0270] Guard column: TSKguardcolumn SuperH-H manufactured by Tosoh Corporation

[0271] Separation column: A column obtained by sequentially connecting "TSKgel SuperH5000," "TSKgel SuperH6000," and "TSKgel SuperH7000," all manufactured by Tosoh Corporation.

[0272] Oven temperature: 40°C

[0273] Flow rate: 0.6mL / min

[0274] Detector: RI detector (trade name "HLC8020" manufactured by Tosoh Corporation)

[0275] Measurement solution: 10 mg of the measurement sample dissolved in 20 mL of THF

[0276] [Modification rate]

[0277] The modification rate was measured as follows by a column adsorption GPC method utilizing the property that the modified conjugated diene polymer is adsorbed on a column.

[0278] Using a sample solution containing the sample and low molecular weight internal standard polystyrene, the amount of adsorption on the silica column was measured from the difference between the chromatograms measured using a column filled with polystyrene gel and the chromatograms measured using a column filled with silica gel, and the modification rate was determined.

[0279] (GPC measurement conditions using a polystyrene column)

[0280] The GPC measurement conditions using a polystyrene column are as follows: 20 μL of the following measurement solution was injected into the GPC measurement apparatus and measurement was performed.

[0281] Device: HLC-8320GPC, manufactured by Tosoh Corporation

[0282] Eluent: THF with 5 mmol / L triethylamine added

[0283] Guard column: TSKguardcolumn SuperH-H, manufactured by Tosoh Corporation

[0284] Column: A column obtained by sequentially connecting "TSKgel SuperH5000," "TSKgel SuperH6000," and "TSKgel SuperH7000," all manufactured by Tosoh Corporation.

[0285] Oven temperature: 40°C

[0286] Flow rate: 0.6mL / min

[0287] Detector: RI detector (HLC8020 manufactured by Tosoh Corporation)

[0288] Measurement solution: 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution.

[0289] (GPC measurement conditions using a silica column)

[0290] The GPC measurement conditions using a silica column are as follows: 50 μL of the following measurement solution was injected into the GPC measurement apparatus and measurement was performed.

[0291] Device: HLC-8320GPC, manufactured by Tosoh Corporation

[0292] Eluent: THF

[0293] Guard column: DIOL 4.6×12.5 mm 5 micron, manufactured by GL Sciences

[0294] Separation column: A column obtained by connecting trade names "Zorbax PSM-1000S", "PSM-300S" and "PSM-60S" manufactured by Agilent Technologies in this order.

[0295] Oven temperature: 40°C

[0296] Flow rate: 0.5mL / min

[0297] Detector: RI detector (HLC8020 manufactured by Tosoh Corporation)

[0298] (Calculation method of modification rate):

[0299] The overall peak area of ​​the chromatogram using a polystyrene column is set to 100, the peak area of ​​the sample is set to P1, and the peak area of ​​the standard polystyrene is set to P2. The overall peak area of ​​the chromatogram using a silica column is set to 100, the peak area of ​​the sample is set to P3, and the peak area of ​​the standard polystyrene is set to P4. The modification rate (%) is calculated by the following formula.

[0300] Modification rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100

[0301] (where P1+P2=P3+P4=100)

[0302] [Coupling rate]

[0303] The chromatogram is measured in the same manner as the method for measuring the peak top molecular weight of the peak with the largest area in the molecular weight distribution curve of GPC described above. When there are two or more peaks, the coupling rate is calculated from the ratio of the uncoupled peak area (low molecular weight side peak) to the coupled peak area (high molecular weight side peak).

[0304] When there is one peak, the coupling rate is 0%. When there are three or more peaks, the peak with the lowest molecular weight is regarded as the peak of the uncoupled component, and the peak of the component present on the higher molecular weight side than this peak is regarded as the coupled peak.

[0305] The peak in this example refers to a portion having a maximum value and sandwiched between a baseline or a minimum value during GPC measurement, and refers to a portion having a peak molecular weight of 10,000 or more and a peak area of ​​5% or more in the maximum value.

[0306] [Mooney viscosity]

[0307] The Mooney viscosity of each polymer was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with JIS K6300 (ISO 289-1) and ISO 289-4. The measurement temperature was set to 100°C.

[0308] Here, after preheating the sample for 5 minutes, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured as the Mooney viscosity (ML (5+4) ).

[0309] [Content of aromatic vinyl monomer units (bonded styrene content) of conjugated diene polymer, 1,2-vinyl bond content, relative intensity of 6.0 ppm or more and less than 6.7 ppm, relative intensity of 6.7 ppm or more and less than 6.94 ppm, relative intensity of 6.94 ppm or more and 7.60 ppm or less]

[0310] Using conjugated diene polymer as a sample, 1 H-NMR measurement measured the amount of bonded styrene, the amount of 1,2-vinyl bonds, (A) relative intensity of 6.0 ppm or more and less than 6.7 ppm, (B) relative intensity of 6.7 ppm or more and less than 6.94 ppm, and (C) relative intensity of 6.94 ppm or more and less than 7.60 ppm.

[0311] 1 The conditions for H-NMR measurement are as follows.

[0312] <Measurement Conditions>

[0313] Measuring equipment: JNM-LA400 (manufactured by JEOL)

[0314] Solvent: deuterated chloroform

[0315] Measurement sample: Conjugated diene polymer

[0316] Sample concentration: 50 mg / mL

[0317] Observation frequency: 400MHz

[0318] Chemical shift standard: 0.05 mass% TMS (tetramethylsilane) relative to deuterated chloroform

[0319] Pulse delay: 2.904 seconds

[0320] Scan times: 64 times

[0321] Pulse width: 45°

[0322] Measurement temperature: 26°C

[0323] [Production of Conjugated Diene Polymer]

[0324] (Example 1) Conjugated diene polymer 1

[0325] As shown in Table 1, a temperature-controllable autoclave with an internal volume of 40 L, equipped with a stirrer and a jacket was used as a reactor. 1,470 g of 1,3-butadiene from which impurities had been removed in advance, 1,330 g of styrene (initial styrene in the table), 21,000 g of cyclohexane, 0.5 mol of tetrahydrofuran (THF) as a polar substance, and 14.1 mmol of 2,2-bis(2-tetrahydrofuryl)propane were added to the reactor, and the internal temperature of the reactor was maintained at 33°C.

[0326] 16.5 mmol of n-butyllithium (represented as nBL in the table) as a polymerization initiator was supplied to the reactor.

[0327] After the polymerization reaction began, the temperature in the reactor rose due to the exotherm of polymerization. Once the temperature rise was confirmed to be below 0.3°C / minute, 200 g of styrene (referred to as "additional styrene added" in the table) was added to further allow the reaction to proceed. The final temperature in the reactor was 81°C. 14.9 mmol of methanol was added to the polymer solution as a reaction terminator.

[0328] To the resulting polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants. The conjugated diene polymer solution was then added dropwise to warm water. The solvent was removed, and the mixture was dried in a dryer to obtain a conjugated diene polymer 1 (referred to as polymer 1 in Table 1 below).

[0329] The obtained conjugated diene polymer 1 was analyzed by the above-mentioned method. The obtained analysis results are shown in Table 4.

[0330] (Examples 2 to 15, Comparative Examples 1 to 12) Conjugated Diene Polymers 2 to 15, 19 to 30

[0331] Except for changing the polymerization formula as shown in Tables 1 to 3, the same method as in Example 1 was used to obtain respective conjugated diene polymers (conjugated diene polymers 2 to 15, 19 to 30).

[0332] To the resulting solutions of the conjugated diene polymers, 12.6 g of n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then the conjugated diene polymer solutions were added dropwise to warm water. The solvent was removed and the polymers were dried using a dryer to obtain conjugated diene polymers (recorded as polymers 2 to 15 and 19 to 30 in the following table).

[0333] The obtained conjugated diene polymers 2 to 15 and 19 to 30 were analyzed by the above-mentioned method. The obtained analysis results are shown in Tables 4 to 6.

[0334] (Example 16) Conjugated diene polymer 16

[0335] As shown in Table 2, a temperature-controllable autoclave with an internal volume of 40 L, equipped with a stirrer and a jacket was used as a reactor. 1,560 g of 1,3-butadiene from which impurities had been removed in advance, 1260 g of styrene (initial styrene in the table), 21,000 g of cyclohexane, 0.73 mol of tetrahydrofuran (THF) and 18.2 mmol of 2,2-bis(2-tetrahydrofuryl)propane as polar substances, and 1.2 mol of potassium tert-amyloxide were added to the reactor, and the internal temperature of the reactor was maintained at 33°C.

[0336] 24.3 mmol of n-butyllithium as a polymerization initiator was supplied to the reactor.

[0337] After the polymerization reaction started, the temperature in the reactor rose due to the exotherm caused by polymerization. Once the temperature rise was confirmed to be below 0.3°C / minute, 180g of styrene (additional styrene added in the table) was added to further allow the reaction to proceed. The final temperature in the reactor was 80°C. 2.4mmol of 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (Compound 1) was added as a coupling agent to the polymer solution and the reaction was allowed to proceed for 15 minutes. 19.0mmol of methanol was then added as a reaction terminator.

[0338] To the resulting polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants. The conjugated diene polymer solution was then added dropwise to warm water, the solvent was removed, and the polymer was dried using a dryer to obtain a conjugated diene polymer 16 (recorded as polymer 16 in Table 2 below).

[0339] The obtained conjugated diene polymer 16 was analyzed by the above-mentioned method. The obtained analysis results are shown in Table 5.

[0340] (Examples 17 and 18) Conjugated diene polymers 17 and 18

[0341] Except for changing the polymerization formula as shown in Table 2, the same method as in Example 16 was used to obtain respective conjugated diene polymers (conjugated diene polymers 17 and 18).

[0342] To the obtained solutions of conjugated diene polymers 17 and 18, 12.6 g of n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, respectively. Then, each conjugated diene polymer solution was added dropwise to warm water, the solvent was removed, and the mixture was dried using a dryer to obtain conjugated diene polymers (recorded as polymers 17 and 18 in Table 2 below).

[0343] The obtained conjugated diene polymers 17 and 18 were analyzed by the above-mentioned method. The obtained analysis results are shown in Table 5.

[0344] The symbols in Tables 1 to 3 below are as follows.

[0345] THF: Tetrahydrofuran

[0346] BOP: 2,2-bis(2-tetrahydrofuryl)propane

[0347] KTA: Potassium tert-amyl alcohol

[0348] KDO: Potassium 3,7-dimethyl-3-octanoate (50% in hexane)

[0349] EMP: 2-(2-ethoxyethoxy)-2-methylpropane

[0350] EGDE: Ethylene glycol diethyl ether

[0351] NaTA: sodium tert-amyl alkoxide

[0352] Compound 1: 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane

[0353] Compound 2: Tetramethoxysilane

[0354]

[0355]

[0356]

[0357]

[0358] [Application Examples 1 to 18, Application Comparative Examples 1 to 12]

[0359] Using the conjugated diene polymers 1 to 30 shown in Tables 4 to 6 as raw material rubbers, conjugated diene polymer compositions containing the respective raw material rubbers were obtained according to the following blending ratios.

[0360] It should be noted that the case of using the conjugated diene polymer of Example 1 is referred to as Application Example 1, and the case of using the conjugated diene polymer of Comparative Example 1 is referred to as Application Comparative Example 1. Similarly, the Example number and Comparative Example number correspond to the Application Example number and Application Comparative Example number, respectively.

[0361] (Conjugated diene polymer composition)

[0362] Raw rubber (conjugated diene polymers 1 to 30): 100.0 parts by mass

[0363] Carbon black (Seast KH (N339) manufactured by Tokai Tanso Co., Ltd.): 80.0 parts by mass

[0364] S-RAE oil (manufactured by Japan Energy Co., Ltd., JOMO Process NC140): 20.0 parts by mass

[0365] Resin (KRISTALEX F85, manufactured by Eastman Co., Ltd.): 20.0 parts by mass

[0366] Wax (Sunnoc N, manufactured by Ouchi Shinko Chemical Co., Ltd.): 1.5 parts by mass

[0367] Zinc white: 2.0 parts by mass

[0368] Stearic acid: 2.0 parts by mass

[0369] Anti-aging agent (N-isopropyl-N'-phenyl-p-phenylenediamine): 1.0 parts by mass

[0370] Sulfur: 1.0 parts by mass

[0371] Vulcanization accelerator (N-cyclohexyl-2-benzothiazolylsulfenamide): 2.5 parts by mass

[0372] Vulcanization accelerator (tetrabenzylthiuram disulfide): 1.0 part by mass

[0373] Total: 231.0 parts by mass

[0374] The above materials were kneaded by the following method to obtain a conjugated diene polymer composition.

[0375] In the first stage of kneading, the raw rubbers (conjugated diene polymers 1 to 27), fillers (carbon black), process oils (S-RAE oil, wax), zinc white, and stearic acid were kneaded using a closed-loop mixer (0.3 L internal volume) equipped with a temperature control device at a filling rate of 65% and a rotor speed of 50 / 57 rpm. The temperature of the closed-loop mixer was controlled to achieve a discharge temperature (mixture) of 155 to 160°C to obtain a modified conjugated diene polymer composition.

[0376] Next, as the second stage of kneading, the mixture obtained above is cooled to room temperature, and then an antioxidant is added and kneaded again. In this case, the discharge temperature (of the mixture) is also adjusted to 155-160°C by temperature control of the mixer.

[0377] After cooling, as the third stage of kneading, sulfur and a vulcanization accelerator were added and kneaded using an open mill set at 70°C.

[0378] Thereafter, the sheets were molded into sheets having a thickness of 2 mm and a thickness of 3 mm, respectively, and vulcanized at 160° C. for 20 minutes using a vulcanizing press.

[0379] In the high-temperature tensile test, a test piece was produced from a vulcanized sheet having a thickness of 2 mm using a punching machine, and in the viscoelasticity test, a test piece was produced from a vulcanized sheet having a thickness of 3 mm using a punching machine.

[0380] In the DIN abrasion test, vulcanization was performed using a mold so that one sample had a diameter of 16 mm and a thickness of 8 mm.

[0381] After vulcanization, the physical properties of the conjugated diene polymer composition were measured.

[0382] The results of physical property measurements are shown in Tables 7 to 9.

[0383] The physical properties of the conjugated diene polymer composition as a sulfide after vulcanization as described above were measured by the following methods.

[0384] ((1) Processability: Mooney viscosity of the composition)

[0385] A portion of the kneaded conjugated diene polymer composition was taken out before molding, and the Mooney viscosity was measured.

[0386] Using a Mooney viscometer, the viscosity was measured after preheating at 100° C. for 1 minute in accordance with JIS K 6300-1 and then rotating the rotor at 2 rpm for 4 minutes.

[0387] When the Mooney viscosity of the composition is 40 or more and 100 or less, the processability is very good; when it is more than 100 and 120 or less, the processability is good; and when it is more than 120 and 150 or less, there is no practical problem.

[0388] On the other hand, when the kneading ratio is less than 40, the composition is likely to adhere to the equipment, resulting in poor processability. When the kneading ratio is 150 or more, the composition has poor cohesiveness during kneading and is likely to break when formed into a sheet, resulting in poor processability.

[0389] The Mooney viscosity of the composition was expressed as ⊚ if it was 30 or more and 100 or less, ⊚ if it was more than 100 and 120 or less, Δ if it was more than 120 and 150 or less, × if it was more than 150, and ×× if it was more than 165.

[0390] ((2) High temperature tensile properties)

[0391] The tensile strength and elongation at 100° C. were measured according to the tensile test method of JIS K 6251.

[0392] The product of the tensile strength and the elongation at 100° C. was defined as the high-temperature tensile property. Tables 7 to 9 show the absolute values ​​of the products and the following evaluations.

[0393] The higher the high-temperature tensile properties at 100°C, the more preferable it is. Using the high-temperature tensile properties of Application Example 13 as a benchmark, an improvement of 0% to 10% was marked as △, an improvement of more than 10% to 30% was marked as ◯, and an improvement of more than 30% was marked as ◎. On the other hand, a deterioration of more than 0% to 10% was marked as ×, and a deterioration of more than 10% was marked as ××.

[0394] ((3) Wet grip and handling stability)

[0395] As indicators of wet grip and steering stability, viscoelastic parameters were measured in a torsional vibration mode using a viscoelasticity tester (ARES) manufactured by Rheometric Scientific.

[0396] Tan δ measured under the conditions of 0° C., a frequency of 10 Hz, and a strain of 1% was used as an indicator of wet grip performance. A larger value indicated better wet grip performance.

[0397] With the measured values ​​of Application Example 13 as a reference and 100 as a value, improvements of 0% to 15% were scored as △, improvements exceeding 15% and 30% or less were scored as ∘, and improvements exceeding 30% were scored as ◎. On the other hand, deterioration exceeding 0% to 30% was scored as ×, and deterioration exceeding 30% was scored as ××.

[0398] Furthermore, the storage modulus measured under the conditions of 50° C., a frequency of 10 Hz, and a strain of 3% was used as an index of steering stability performance, and a larger value was evaluated as indicating better steering stability.

[0399] With the measured values ​​of Application Example 13 as a reference and 100 as a value, an improvement of 0% to 15% was marked as △, an improvement of more than 15% to 30% was marked as 0, and an improvement of more than 30% was marked as ◎. On the other hand, a deterioration of more than 0% to 30% was marked as ×, and a deterioration of more than 30% was marked as ××.

[0400] ((4) Wear resistance)

[0401] Wear was measured using an Akron abrasion tester (manufactured by Yasuda Seiki Co., Ltd.) in accordance with JIS K 6264-2 at a load of 44.1 N and 1000 revolutions. The lower the wear, the better. Based on the measured value of Application Example 13, with this value set as 100, an improvement of 0% to 5% was scored as △, an improvement of more than 5% to within 15% was scored as ∘, and an improvement of more than 15% was scored as ◎. On the other hand, a deterioration of more than 0% to within 20% was scored as ×, and a deterioration of more than 20% was scored as ××.

[0402] Tables 7 to 9 show relative values ​​when the measured value of Example 13 is set to 100, and show the above evaluation.

[0403]

[0404] This specification evaluates five physical properties: processability, high-temperature tensile properties, wet grip, abrasion resistance, and handling stability. In the Examples, "×" indicates one or fewer. In the Comparative Examples, "×" indicates two or more. Note that "×" in the table means "×" is counted as two.

[0405] It can be seen that compared with the conjugated diene polymers obtained in Comparative Examples 1 to 12, the conjugated diene polymer compositions using Comparative Examples 1 to 12, and the conjugated diene polymer crosslinked products, the conjugated diene polymers obtained in Examples 1 to 18 and the conjugated diene polymer compositions using Examples 1 to 18 have practically sufficient high-temperature tensile strength, wet grip performance, handling stability, and wear resistance while maintaining processability.

[0406] This application is based on Japanese patent application No. 2023-044151 filed with the Japan Patent Office on March 20, 2023, the contents of which are incorporated herein by reference.

[0407] Industrial Applicability

[0408] The conjugated diene polymer and the conjugated diene polymer composition of the present embodiment have industrial applicability as tires, gaskets or spacers, sealing materials, vibration-isolating rubber, vibration-damping rubber, vibration-isolating rubber, conveyor belts, power transmission belts, shoe outsoles or shoe midsoles, automobile weather stripping, glass run channels, trunk lids, railway vehicle parts, aircraft parts, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary products, hoses for industrial and various uses, battery cases, adhesives, wire coatings, window frame rubber, rubber rollers, rubber rollers for OA equipment or textiles, numeric keypads, keyboard covers, underwater goggles, swimming caps, container bags, marine-related parts, interior flooring materials, artificial muscle materials, and materials for various industrial products.

Claims

1. A conjugated diene polymer, wherein The content of the aromatic vinyl monomer unit is 35% by mass or more and 70% by mass or less, The 1,2-vinyl bond content in the conjugated diene monomer unit is 21 mol% or more and 65 mol% or less, about 1 In H-NMR, (A) has a relative intensity of 6.0 ppm or more and less than 6.7 ppm, (B) has a relative intensity of 6.7 ppm or more and less than 6.94 ppm, and (C) has a relative intensity of 6.94 ppm or more and 7.60 ppm or less. When the sum of (A) + (B) + (C) is set to 100%, (A) is 0.5% or more and 25% or less, (B) is 2% or more and 25% or less, and (C) is 60% or more and 96.5% or less. In a molecular weight distribution curve obtained by gel permeation chromatography (GPC), the peak top molecular weight of the peak with the largest area is 150,000 to 600,000.

2. The conjugated diene polymer according to claim 1, wherein The content of the aromatic vinyl monomer unit is 45% by mass or more and 60% by mass or less.

3. The conjugated diene polymer according to claim 1, wherein The modification rate is less than 60%.

4. The conjugated diene polymer according to claim 1, wherein The total value of the relative intensities of (A) + (B) is 17% or more and 39% or less.

5. The conjugated diene polymer according to claim 1, wherein The relative intensity of (A) is 5% or more and 15% or less, The relative intensity of (C) is 60% or more and 96% or less.

6. The conjugated diene polymer according to claim 1, wherein The relative intensity of (A) is 0.5% or more and 15% or less, The relative intensity of (C) is 60% or more and 96% or less.

7. The conjugated diene polymer according to claim 1, which is a rubber block molded product. 8 . A conjugated diene polymer composition comprising the conjugated diene polymer according to claim 1 . 9 . The conjugated diene polymer composition according to claim 8 , which is a composition for tires. 10 . The conjugated diene polymer composition according to claim 8 , which is a composition for shoe soles. 11 . The conjugated diene polymer composition according to claim 8 , which is a composition for vibration-proof rubber.

Images