Conjugated diene polymers, conjugated diene polymer compositions, vibration-damping rubber, and molded articles

Abstract

To provide a conjugated diene-based polymer and the like that are excellent in dynamic magnification. 【Solution】 A conjugated diene-based polymer having structural units derived from a conjugated diene-based compound, wherein the content of aromatic vinyl monomer units is 5 mass% or less, the 1,2-vinyl bond content is 10 mol% or more and 22 mol% or less, the modification rate is 50 mass% or more and 99 mass% or less, the silicon content is 50 ppm or less, and the peak area reduction rate R1, calculated from the area value C1 of all peaks in the molecular weight distribution curve D1 obtained by subjecting the conjugated diene-based polymer before performing the following operation (i) to gel permeation chromatography (GPC) measurement, and the area value C2 of all peaks in the molecular weight distribution curve D2 obtained by subjecting the extract obtained after performing the operation (i) on the conjugated diene-based polymer to GPC measurement, is 60% or more and 99% or less, defined as 100×(C1-C2) / C1. (Operation (i)) To 100 parts of the conjugated diene-based polymer, 50 parts of carbon black is added to obtain a compound. The compound is immersed in toluene at 25°C for 1 day. After the immersion, the portion of the conjugated diene-based polymer dissolved in toluene is recovered by vacuum filtration, the toluene is evaporated, and the resulting precipitate is dissolved in tetrahydrofuran to obtain an extract.

Description

[Technical Field]

[0001] The present invention relates to conjugated diene polymers, conjugated diene polymer compositions, vibration-damping rubber, and molded articles. [Background technology]

[0002] Vulcanized crosslinked rubber compositions for vibration damping rubber and industrial material applications generally use rubber materials containing natural rubber, which has excellent vibration damping performance and rubber reinforcement properties, and carbon black as a filler (see, for example, Patent Document 1).

[0003] By introducing functional end groups into the polymer chains of rubber materials, the polymers can interact more effectively with fillers used in the production of rubber compounds. Physical or chemical interaction with the filler surface reduces the mobility of polymer chains in the compound matrix, thereby reducing energy dissipation under dynamic stress. Simultaneously, these functional groups can improve the dispersion of fillers in the rubber composition, leading to weakening of the filler network and improvement of the compound's properties (see, for example, Non-Patent Document 1).

[0004] Studies are underway to improve the dynamic magnification of vibration-damping rubber by dispersing carbon black (see, for example, Non-Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-35253 [Non-patent literature]

[0006] [Non-Patent Document 1] Network Polymers 2017 Vol.38 No.1 "Review Article: Anionic Polymerization and its Industrial Applications" [Non-Patent Document 2] Journal of the Japan Rubber Association, 1991, Vol. 64, No. 12, pp. 52-58, "Modification of Vibration Characteristics by Rubber Modification" [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the polymers disclosed in Patent Document 1 and Non-Patent Documents 1-2 have room for further improvement in terms of the dynamic magnification required for vibration-damping rubber.

[0008] This invention was made based on the above, and aims to provide a conjugated diene polymer with excellent dynamic magnification. [Means for solving the problem]

[0009] The present inventors, after diligently studying to solve the problems of the prior art described above, have found that the above problems can be solved by using a conjugated diene polymer in which the content of aromatic vinyl monomer units, the amount of 1,2-vinyl bonds, the modification rate, the silicon content, and the predetermined GPC area reduction rate are all within a specific range, and have completed the present invention.

[0010] In other words, the present invention encompasses the following embodiments. [1] A conjugated diene polymer having structural units derived from a conjugated diene compound, The aromatic vinyl monomer unit content is 5% by mass or less. The amount of 1,2-vinyl bond is 10 mol% or more and 22 mol% or less. The denaturation rate is between 50% by mass and 99% by mass. The silicon content is 50 ppm or less. A conjugated diene polymer in which the peak area reduction rate R1, calculated from the area value C1 of all peaks in the molecular weight distribution curve D1 obtained by subjecting the conjugated diene polymer to gel permeation chromatography (GPC) measurement before performing the following operation (i), and the area value C2 of all peaks in the molecular weight distribution curve D2 obtained by subjecting the extract obtained after performing the operation (i) on the conjugated diene polymer to GPC measurement, is 60% or more and 99% or less, with R1 being 100 × (C1 - C2) / C1. (Operation (i)) To 100 parts of the conjugated diene polymer, 50 parts of carbon black are added to obtain a compound. The compound is immersed in toluene at 25°C for 1 day. After immersion, the portion of the conjugated diene polymer dissolved in toluene is recovered by vacuum filtration, the toluene is evaporated, and the resulting precipitate is dissolved in tetrahydrofuran to obtain an extract. [2] The conjugated diene polymer according to [1], wherein in the molecular weight distribution curve D1, there are two or more peaks with a peak area of ​​5% or more. [3] The conjugated diene polymer according to [1] or [2], wherein when the peak with the largest peak area among all peaks in the molecular weight distribution curve D1 is defined as peak (A1), and the peak with the largest peak area among all peaks in the molecular weight distribution curve D2 is defined as peak (A2), the peak area reduction rate R2 is 70% or more and 99% or less, calculated as 100 × (A1 - A2) / A1. [4] Of all the peaks in the molecular weight distribution curve D1, peak (A1) is the peak on the lowest molecular weight side. The conjugated diene polymer according to [3], wherein, among all the peaks in the molecular weight distribution curve D2, peak (A2) is the peak on the lowest molecular weight side. [5] Of all the peaks in the molecular weight distribution curve D1, the peak located on the highest molecular weight side excluding the peak (A1) is defined as peak (B1), and of all the peaks in the molecular weight distribution curve D2, the peak located on the highest molecular weight side excluding the peak (A2) is defined as peak (B2), the value of the peak area reduction rate R3 calculated as 100×(B1-B2) / B1 is equal to or less than the value of the peak area reduction rate R2, the conjugated diene-based polymer according to [3] or [4]. [6] The conjugated diene-based polymer according to [5], wherein the peak area reduction rate R3 is 50% or more and 99% or less. [7] The conjugated diene-based polymer according to any one of [1] to [6], wherein the coupling rate is 7% by mass or more and 15% by mass or less. [8] The conjugated diene-based polymer according to any one of [1] to [7], wherein the uncoupled partial modification rate is 50% by mass or more and 99% by mass or less. [9] The conjugated diene-based polymer according to any one of [1] to [8], wherein the tin content is 20 ppm or less.

[10] The conjugated diene-based polymer according to any one of [1] to [9], wherein the Mooney viscosity at 100°C is 35 or more and 130 or less.

[11] a rubber component, a filler, and the conjugated diene-based polymer composition comprising the rubber component includes the conjugated diene-based polymer according to any one of [1] to

[10] , and the filler includes carbon black.

[12] The conjugated diene-based polymer composition according to

[11] , wherein the content of the filler is 10 parts by mass or more and 300 parts by mass or less relative to 100 parts by mass of the rubber component. The conjugated diene-based polymer composition according to

[11] , wherein 10% by mass or more of the rubber component is the conjugated diene-based polymer.

[13] The conjugated diene-based polymer composition according to

[11] or

[12] , wherein 90% by mass or more of the filler is carbon black.

[14] Vibration-damping rubber comprising a conjugated diene polymer composition as described in any of

[11] to

[13] .

[15] A molded article comprising a conjugated diene polymer composition described in any of

[11] to

[14] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide conjugated diene polymers and the like that have excellent dynamic magnification. [Modes for carrying out the invention]

[0012] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). Note that this embodiment is illustrative for explaining the present invention, and the present invention is not limited to the embodiments shown below. The present invention can be implemented in various modifications within the scope of its gist.

[0013] [Conjugated diene polymers] The conjugated diene polymer of this embodiment is a conjugated diene polymer having structural units derived from a conjugated diene compound (hereinafter also referred to as "conjugated diene monomer units"), wherein the content of aromatic vinyl monomer units (structural units derived from aromatic vinyl compounds) is 5% by mass or less, the amount of 1,2-vinyl bonds is 10 mol% or more and 22 mol% or less, the denaturation rate is 50% by mass or more and 99% by mass or less, the silicon content is 50 ppm or less, and the peak area reduction rate R1 calculated from the area value C1 of all peaks in the molecular weight distribution curve D1 obtained by subjecting the conjugated diene polymer to gel permeation chromatography (GPC) measurement before performing the following operation (i), and the area value C2 of all peaks in the molecular weight distribution curve D2 obtained by subjecting the extract obtained after performing the operation (i) on the conjugated diene polymer to GPC measurement, is 60% or more and 99% or less, with R1 being 100 × (C1 - C2) / C1. (Operation (i)) To 100 parts of the conjugated diene polymer, 50 parts of carbon black are added to obtain a compound. The compound is immersed in toluene at 25°C for 1 day. After immersion, the portion of the conjugated diene polymer dissolved in toluene is recovered by vacuum filtration, the toluene is evaporated, and the resulting precipitate is dissolved in tetrahydrofuran to obtain an extract.

[0014] The conjugated diene polymer of this embodiment has the above-described structure and therefore exhibits excellent dynamic magnification.

[0015] As described above, the conjugated diene polymer of this embodiment has conjugated diene monomer units and may optionally contain aromatic vinyl monomer units. In the conjugated diene polymer of this embodiment, it is preferable that the so-called microstructure of the copolymer of the conjugated diene compound and the aromatic vinyl compound (content of aromatic vinyl monomer units, amount of 1,2-vinyl bonds, etc.) is controlled. In the conjugated diene polymer of this embodiment, from the viewpoint of dynamic magnification, the content of aromatic vinyl monomer units is 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. The content of aromatic vinyl monomer units is, 1 It can be measured by 1H-NMR. Specifically, it can be measured using the method described in the examples. Furthermore, the content of aromatic vinyl monomer units can be controlled within the above numerical range by adjusting the amount of aromatic vinyl compound added during polymerization.

[0016] (Content of aromatic vinyl blocks) In this embodiment, the conjugated diene polymer preferably has an aromatic vinyl block content of 7% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less, from the viewpoint of dynamic regeneration. On the other hand, from the viewpoint of cold flow properties, it is preferably 1% by mass or more, and particularly preferably 1.5% by mass or more.

[0017] The aromatic vinyl block content in this application can be measured by the method described in IMKolthoff, et al. J. Polym. Sci. 1,429 (1946), or more specifically, by the method described in the examples.

[0018] Aromatic vinyl compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of ease of industrial availability. These may be used individually or in combination of two or more types.

[0019] Furthermore, while not limited to the following, examples of conjugated diene compounds include 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 from the viewpoint of ease of industrial availability, and 1,3-butadiene is particularly preferred. These may be used individually or in combination of two or more types.

[0020] (Amount of 1,2-vinyl bond) In this embodiment, the amount of 1,2-vinyl bonds in the conjugated diene polymer is the molar ratio of the amount of 1,2-vinyl bonds based on the content of conjugated diene monomer units. From the viewpoint of productivity of the conjugated diene polymer, it is 10 mol% or more, preferably 13 mol% or more, and more preferably 14 mol% or more. On the other hand, from the viewpoint of improving the dynamic magnification and tensile properties of the conjugated diene polymer in this embodiment, and further from the viewpoint of suppressing gelation of the conjugated diene polymer, it is 22 mol% or less, preferably 21 mol% or less, more preferably 20 mol% or less, and even more preferably less than 20 mol%. The amount of 1,2-vinyl bonds is 1 It can be measured by 1H-NMR. Specifically, it can be measured using the method described in the examples. The amount of 1,2-vinyl bond can be controlled within the above numerical range by adjusting the reaction start temperature, reaction end temperature, and the type and amount of polar substance added during polymerization.

[0021] Furthermore, the polymerization method for the conjugated diene polymer in this embodiment is not limited to the following, but it is preferably carried out by living anionic polymerization, and adiabatic polymerization is preferred.

[0022] (Number of peaks, peak molecular weight, peak area, and molecular weight distribution in the molecular weight distribution curve obtained by GPC measurement) From the viewpoint of cold flow properties and processability, the conjugated diene polymer of this embodiment preferably has two or more peaks with a peak area of ​​5% or more in its molecular weight distribution curve D1, which is obtained by GPC (gel permeation chromatography). It may also have three or more peaks. On the other hand, from the viewpoint of improving the reproducibility of polymerization, the number of peaks with a peak area of ​​5% or more is preferably five or less, more preferably four or less, even more preferably three or less, and particularly preferably two.

[0023] In this embodiment, the peaks originating from the conjugated diene polymer in the molecular weight distribution curves D1 and D2 measured by GPC (gel permeation chromatography) refer to the portion between the baseline and the minimum value. In this embodiment, a peak refers to a peak with a peak area of ​​2% or more.

[0024] Before subjecting the conjugated diene polymer of this embodiment to operation (i), when the molecular weight distribution curve D1 obtained by GPC (gel permeation chromatography) is shown, the peak with the largest peak area is designated as peak (A1). Preferably, peak (A1) is the peak on the low molecular weight side among the peaks with a peak area of ​​5% or more. If there are two or more peaks with the largest area, and multiple peaks have the same area, the peak with the smaller molecular weight is designated as peak (A1).

[0025] Furthermore, the peak molecular weight of peak (A1) is preferably 250,000 or more, more preferably 300,000 or more, even more preferably 350,000 or more, and particularly preferably 380,000 or more, from the viewpoint of reducing adhesion during production and the tensile properties of the conjugated diene polymer crosslinked product. On the other hand, from the viewpoint of processability, it is preferably 1,200,000 or less, more preferably 1,000,000 or less, even more preferably 800,000 or less, and particularly preferably 600,000 or less. The peak molecular weight is the molecular weight at the point where the value becomes 0 when the molecular weight distribution curve of the peak derived from the conjugated diene polymer in the molecular weight distribution curves D1 and D2 is differentiated. The peak top molecular weight can be controlled to the above numerical range by controlling the amount of polymerization initiator and coupling agent added, which will be described later.

[0026] Furthermore, the peak area of ​​peak (A1) is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably exceeding 85% from the viewpoint of tensile properties. On the other hand, from the viewpoint of cold flow properties, it is preferably 95% or less, more preferably 94% or less, even more preferably 93% or less, and particularly preferably 90% or less.

[0027] In the molecular weight distribution curve D1, if there are two or more peaks with a peak area of ​​5% or more relative to the entire polymer, and peak (A1) is located on the lowest molecular weight side among the aforementioned peaks with a peak area of ​​5% or more, and the area of ​​peak (A1) is between 80% and 95%, then the dynamic magnification, tensile properties, and cold flow properties tend to be further improved. The peak area of ​​peak (A1) can be controlled to the above numerical range by controlling the amount of polymerization initiator and coupling agent added, as described later.

[0028] In this embodiment, it is preferable that peak (A1) is located on the lowest molecular weight side among the peaks. Furthermore, it is preferable that the conjugated diene polymer contained in peak (A1) is a highly linear polymer, and a high proportion of modified polymer is also preferable. It is presumed that the steric hindrance around the modified group is small because the ends of the highly linear polymer are modified, making it easier to interact with the functional groups of the filler, thereby improving the dispersibility of the filler and tending to improve the dynamic magnification. The following is a presumption regarding the contribution of the functionally modified conjugated diene polymer to the improvement of dynamic magnification. To improve the dynamic magnification, it is preferable to lower the dynamic modulus in the low-strain region. However, in the low-strain region, the dynamic modulus is high due to the interaction of fillers. Here, it is hypothesized that using a conjugated diene polymer modified with a modifying group will cause the modifying group to interact with the fillers, dispersing them, lowering the dynamic modulus in the low-strain region, and thus improving the dynamic magnification.

[0029] In this embodiment, when the conjugated diene polymer is measured by GPC (gel permeation chromatography), the peak with the highest molecular weight, excluding peak (A1), is designated as peak (B1). From the viewpoint of cold flow properties, the peak molecular weight of peak (B1) is preferably 500,000 or more, more preferably 550,000 or more, and even more preferably 600,000 or more. From the viewpoint of suppressing gelation, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,200,000 or less.

[0030] (molecular weight distribution) In this embodiment, the conjugated diene polymer has a molecular weight distribution of 1.02 or higher, more preferably 1.03 or higher, and even more preferably 1.05 or higher, from the viewpoint of processability. On the other hand, from the viewpoint of dynamic magnification, it is preferably 2.5 or lower, more preferably 2.0 or lower, even more preferably 1.8 or lower, and even more preferably 1.5 or lower.

[0031] The number of peaks, molecular weight distribution, and peak top molecular weight of the conjugated diene polymer in this embodiment can be measured by gel permeation chromatography (GPC), and the detailed conditions are described in the examples below.

[0032] In this embodiment, the conjugated diene polymer exhibits a high overall GPC peak area reduction rate before and after the aforementioned operation (i). Specifically, when C1 is the area value of all peaks in the molecular weight distribution curve D1 obtained by subjecting the conjugated diene polymer before operation (i) to GPC measurement, and C2 is the area value of all peaks in the molecular weight distribution curve D2 obtained by subjecting the extract obtained after operation (i) to GPC measurement, the peak area reduction rate R1 calculated as 100 × (C1 - C2) / C1 is 60% or more, preferably 65% ​​or more, more preferably 70% or more, and even more preferably exceeding 75% from the viewpoint of dynamic magnification. On the other hand, the area reduction rate R1 may be 99% or less from the viewpoint of production stability. The area reduction rate R1 of the conjugated diene polymer in this embodiment can be controlled to the above numerical range by controlling the modification rate and the type of modifying agent.

[0033] In this embodiment, when the peak with the largest peak area among all peaks in the molecular weight distribution curve D1 is defined as peak (A1), and the peak with the largest peak area among all peaks in the molecular weight distribution curve D2 is defined as peak (A2), the peak area reduction rate R2 calculated as 100 × (A1 - A2) / A1 is preferably 70% or more, more preferably 75% or more, and particularly preferably exceeding 80% from the viewpoint of dynamic magnification. On the other hand, from the viewpoint of production stability, it may be 99% or less. Furthermore, it is particularly preferable that peak (A1) is the peak on the lowest molecular weight side, peak (A2) is the peak on the lowest molecular weight side, and that the peak area reduction rate R2 satisfies the above range.

[0034] When, among all the peaks in the molecular weight distribution curve D1, excluding peak (A1), the peak furthest towards the polymer side is defined as peak (B1), and among all the peaks in the molecular weight distribution curve D2, excluding peak (A2), the peak furthest towards the polymer side is defined as peak (B2), it is preferable that the value of the peak area reduction rate R3, calculated as 100 × (B1 - B2) / B1, is less than or equal to the value of the peak area reduction rate R2. Furthermore, from the viewpoint of dynamic magnification, the peak area reduction rate R3 is preferably 50% or more, more preferably 55% or more, and particularly preferably over 60%. On the other hand, from the viewpoint of production stability, it may be 99% or less.

[0035] To achieve the above range, it is preferable to use a compound containing an amine as the coupling agent.

[0036] (Moony viscosity) In this embodiment, the conjugated diene polymer preferably has a Mooney viscosity of 25 or higher at 100°C, more preferably 30 or higher, even more preferably 35 or higher, and even more preferably 40 or higher, from the viewpoint of the tensile properties of the crosslinked conjugated diene polymer. On the other hand, from the viewpoint of suppressing cold flow of the bale and suppressing gelation in the production process, it is preferably 130 or lower, more preferably 110 or lower, even more preferably 100 or lower, and particularly preferably 90 or lower. The above Mooney viscosity can be measured by the method described in the examples below. The Mooney viscosity described above can be controlled by the microstructure of the conjugated diene polymer, its molecular weight and molecular weight distribution, and the ratio of branched components resulting from the coupling reaction described later.

[0037] (Coupling) The conjugated diene polymer of this embodiment may also be a conjugated diene polymer obtained by performing a coupling reaction using a bifunctional or more reactive compound (hereinafter also referred to as a "coupling agent") on the active end of a conjugated diene polymer obtained through a polymerization step. In the coupling reaction step, a coupling agent is used on one end of the active end of the conjugated diene polymer to perform a coupling reaction and obtain a conjugated diene polymer.

[0038] The coupling agent is not particularly limited, but examples include coupling agents having one or more functional groups such as epoxy groups, carbonyl groups, carboxylic acid ester groups, carboxylic acid amide groups, acid anhydride groups, phosphate ester groups, phosphite ester groups, epithio groups, thiocarbonyl groups, thiocarboxylic acid ester groups, dithiocarboxylic acid ester groups, thiocarboxylic acid amide groups, imino groups, ethyleneimino groups, halogen groups, alkoxysilyl groups, isocyanate groups, thioisocyanate groups, conjugated diene groups, and aryl vinyl groups. Among the coupling agents, nitrogen atom-containing coupling agents can also be used as modifying agents as described later. Furthermore, from the viewpoint of suppressing pipe corrosion, it is preferable to use a coupling agent that does not contain chlorine.

[0039] The coupling agents are not limited to the following, but include, for example, halogenated silane compounds such as silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethyltrichlorosilicon, monoethyltrichlorosilicon, monobutyltrichlorosilicon, monohexyltrichlorosilicon, monomethyltribromosilicon, and bistrichlorosilylethane, and alkoxyhalogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane.

[0040] Furthermore, coupling agents are not limited to the following, but examples include alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and alkyltriphenoxysilane; and compounds having an imino group and an alkoxysilyl group such as tristrimethoxysilylpropylamine, triethoxysilylpropylamine, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propaneamine, N-(1,3-dimethylbutylidene)-3-(tributoxysilyl)-1-propaneamine, N-methylpropyridene)-3-(triethoxysilyl)-1-propaneamine, N-ethylidene-3-(triethoxysilyl)-1-propaneamine, and N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole.

[0041] Furthermore, the coupling agents are not limited to, but include, for example, 2-[3-(trimethoxysilyl)propyl]-1,3-dimethylimidazolidinone, 2-[3-(trimethoxysilyl)propyl]-1,3-(bistrimethylsilyl)imidazolidinone, 2-(diethoxydiethylsilyl)-1,3-diethylimidazolidinone, 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)-imidazolidinone 1-yl]-ethyl}dimethylamine, 5-(trimethoxysilyl)-1,3-bis-(2-methoxyethyl)-hexahydropyrimidine, 5-(ethyldimethoxysilyl)-1,3-bis-(2-trimethylsilylethyl)-hexahydropyrimidine-1,3-dimethylimidazolidinone, 2-(3-diethoxyethylsilyl-propyl)-1,3-diethylim Dazolidinone, 2-(3-triethoxysilyl-propyl)-1,4-diethylpiperazine, 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)-imidazolidinone-1-yl]-ethyl}dimethylamine, 5-(3-trimethyl Toxysilyl-propyl)-1,3-bis-(2-methoxyethyl)-hexahydropyrimidine, 5-(3-ethyldimethoxysilyl-propyl)-1,3-bis-(2-trimethylsilylethyl)-hexahydropyrimidine, 2-[3-(trimethoxysilyl)propyl]-1,3-bis(trimethylsilyl)imidazolidinone, 2-(diethoxyethylsilyl)-1,3-bis(triethylsilyl)imidazolidinone, 2-(triethoxysilyl)-1,4-bis(trimethylsilyl)piperazine, 2-(dimethoxymethylsilyl)-1,Examples include 4-bis(trimethylsilyl)piperazine and 5-(triethoxysilyl)-1,3-bis(tripropylsilyl)hexahydropyrimidine.

[0042] Furthermore, the coupling agent is not limited to the following, but for example, [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- Examples include (1-dodecamethyleneimino)propyl]triethoxysilane, [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-(trimethoxysilanyl)-ethyl]-N,N',N'-trimethylethane-1,2-diamine, and N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane.

[0043] Furthermore, the coupling agent is not limited to the following but includes epoxy compounds such as tetraglycidylmetoxylendiamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane, and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane. Furthermore, isocyanate compounds such as 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, diphenylmethanediisocyanate, diphenylethanediisocyanate, and 1,3,5-benzenetriisocyanate, not limited to the following.

[0044] Furthermore, the coupling agents are not limited to the following, but include, for example, 3-(4-methylpiperazine-1-yl)propyltriethoxysilane, 1-[3-(diethoxyethylsilyl)propyl]-4-methylpiperazine, 1-[3-(trimethoxysilyl)propyl]-3-methylimidazolidinone, 1-[3-(diethoxysilyl)propyl]-3-ethylimidazolidinone, 1-[3-(triethoxysilyl)propyl]-3-methylhexahydropyrimidine, 1-[3-(dimethoxymethylsilyl)propyl]-3-methylhexahydropyrimidine, 3-[3-(tributoxysilyl)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]imidazolidinone, (2-{3-[3-(trimethylsilyl)propyl ]tetrahydropyrimidine-yl(ethyl)dimethylamine, 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)imidazolidinone, 2-(trimethoxysilyl) Examples include lanyl)-1,3-dimethylimidazolidinone, 1-[3-(triethoxysilyl)propyl]-3-(trimethylsilyl)imidazolidinone, 1-[3-(dimethoxymethylsilyl)propyl]-3-(trimethylsilyl)hexahydropyrimidine, 1-[3-(triethoxysilyl)propyl]-3-(trimethylsilyl)hexahydropyrimidine, and 1-[4-(triethoxysilyl)propyl]-4-(trimethylsilyl)piperazine.

[0045] (Coupling rate) From the viewpoint of cold flow properties, the coupling rate of the conjugated diene polymer in this embodiment is preferably 5% or more, more preferably 7% or more, and even more preferably 10% or more. On the other hand, from the viewpoint of dynamic magnification, the coupling rate is preferably 30% or less, preferably 25% or less, more preferably 20% or less, and particularly preferably 15% or less.

[0046] (degeneration) The conjugated diene polymer of this embodiment may be modified. Modification refers to modifying a conjugated diene polymer with a nitrogen-containing compound. Modification methods are not particularly limited, but include using a polymerization initiator containing a nitrogen-containing compound, using a nitrogen-containing compound as a polymerization monomer, using the aforementioned nitrogen atom-containing coupling agent, reacting a non-coupling nitrogen-containing compound at the reaction termination end, and modifying the conjugated diene polymer after polymerization by reacting the double bond with a nitrogen-containing compound.

[0047] Polymerization initiators containing nitrogen-containing compounds include, but are not limited to, the following, examples: 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 organolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, n-propyllithium, and i-propyllithium.

[0048] Furthermore, examples of non-coupling nitrogen-containing compounds include, but are not limited to, 1,3-diethyl-2-imidazolinone, 1,3-dimethyl-2-imidazolinone, 1,3-dipropyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 1-methyl-3-propyl-2-imidazolinone, 1-methyl-3-butyl-2-imidazolinone, 1,3-dihydro-1,3-dimethyl-2H-imidazole-2-one, N-methyl-2-pyrrolidone, 1-phenyl-2-pyrrolidone, and N-methyl-ε-caprolactam.

[0049] (Degeneration rate) In this specification, unless otherwise specified, "modification rate" represents the mass ratio of the polymer having nitrogen atom-containing functional groups to the total amount of the conjugated diene polymer. For example, when a nitrogen atom-containing modifying agent is reacted with the terminal end of a polymer, the mass ratio of the polymer having nitrogen atom-containing functional groups due to the nitrogen atom-containing modifying agent to the total amount of the polymer is expressed as the modification rate. As mentioned above, nitrogen atom-containing coupling agents are also included in nitrogen atom-containing modifying agents. On the other hand, when a polymer is branched with a branching agent containing nitrogen atoms, the resulting copolymer will also have nitrogen atom-containing functional groups, and this branched polymer will also be counted as a polymer having nitrogen atom-containing functional groups when calculating the modification rate. In other words, in this specification, a polymer having nitrogen atom-containing functional groups refers to a polymer having nitrogen atom-containing functional groups due to a nitrogen atom-containing modifying agent and a branched polymer due to a branching agent containing nitrogen atom-containing functional groups, and the mass ratio of the sum of these is the "modification rate."

[0050] In this embodiment, the conjugated diene polymer has a modification rate of 50% or more, preferably 60% or more, more preferably 65% ​​or more, and particularly preferably 70% or more, as described above. On the other hand, from the viewpoint of improving productivity due to the difficulty of removing impurities during polymerization, the modification rate is 99% or less, preferably 97% or less, more preferably 95% or less, and even more preferably 93% or less.

[0051] The denaturation rate of the conjugated diene polymer in this embodiment can be measured, for example, by chromatography that can separate the functional group-containing denatured component from the undenatured component. One such chromatography method is to use a gel permeation chromatography column packed with a polar substance such as silica that adsorbs specific functional groups, and quantify the unadsorbed component using an internal standard for comparison (column adsorption GPC method). More specifically, the denaturation rate can be determined by measuring the amount adsorbed onto the silica column from the difference between the chromatogram measured on a polystyrene gel column and the chromatogram measured on a silica column for a sample solution containing the sample and a low molecular weight internal standard polystyrene. Even more specifically, the denaturation rate can be measured by the method described in the examples.

[0052] The modification rate of the conjugated diene polymer in this embodiment can be controlled to the above numerical range by, for example, controlling the amount of modification agent added and the polymerization reaction temperature to a low level, thereby suppressing the deactivation of the active ends.

[0053] In the conjugated diene polymer of this embodiment, it is preferable that the uncoupled partial modification rate is 50% by mass or more and 99% by mass or less. The uncoupled partial modification rate can be determined based on the method described in the examples below, and can be controlled to the above range by the method described above.

[0054] (Silicon content) The conjugated diene polymer of this embodiment has a total silicon content of 50 ppm or less from the viewpoint of improving dynamic magnification and production stability. Preferably, it is 40 ppm or less, more preferably 30 ppm or less, even more preferably 20 ppm or less, and particularly preferably 15 ppm or less.

[0055] (Tin content) The conjugated diene polymer of this embodiment has a total tin content of 20 ppm or less from the viewpoint of improving dynamic magnification and reducing corrosiveness to production equipment and environmental pollution. Preferably, it is 15 ppm or less, more preferably 10 ppm or less, and even more preferably 10 ppm or less.

[0056] In this embodiment, the silicon and tin content in the conjugated diene polymer refers to the content of silicon and tin bonded to the conjugated diene polymer. It does not include the content of silicon-containing compounds or tin-containing compounds added to the polymer as additives. The silicon and tin content of the conjugated diene polymer in this embodiment can be controlled by the type of monomer used in polymerization, the type of coupling agent, the modifier, and the amount of these added.

[0057] [Method for producing conjugated diene polymers] The conjugated diene polymer of this embodiment is obtained by carrying out a polymerization step in which an aromatic vinyl compound and a conjugated diene compound are polymerized using a predetermined polymerization initiator. Preferably, a coupling reaction step and / or a modification reaction step may be carried out using the coupling agent and modification agent described above, and a hydrogenation step may be carried out thereafter. A branching step may be carried out using a branching agent before the coupling reaction step and modification step.

[0058] (Polymerization process) At least an organic monolithium compound can be used as the polymerization initiator in the polymerization process.

[0059] Examples of organic monolithium compounds include, but are not limited to, low-molecular-weight compounds and solubilized oligomeric organic monolithium compounds.

[0060] Furthermore, examples of organic monolithium compounds include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond, depending on the bonding mode between the organic group and its lithium.

[0061] The amount of organic monolithium compound used as a polymerization initiator is preferably determined by the structure of the target conjugated diene polymer and the molecular weight of the conjugated diene polymer.

[0062] The amount of monomers used, such as conjugated diene compounds, relative to the amount of polymerization initiator used, is related to the degree of polymerization. Specifically, it tends to be related to the number-average molecular weight and / or weight-average molecular weight and peak-top molecular weight.

[0063] Therefore, to increase the molecular weight, it is best to adjust the amount of polymerization initiator used to decrease it, and to decrease the molecular weight, it is best to adjust the amount of polymerization initiator used to increase it.

[0064] From the viewpoint of using an organic monolithium compound as a method for introducing a nitrogen atom into a conjugated diene polymer, alkyllithium compounds having a substituted amino group or dialkylaminolithium compounds are preferred. In this case, a conjugated diene polymer having a nitrogen atom consisting of an amino group at the polymerization initiation end can be obtained. A substituted amino group is an amino group that does not have an active hydrogen or has a structure in which the active hydrogen is protected.

[0065] Alkyl lithium compounds having an amino group that does not possess active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0066] Alkyllithium compounds having an amino group with a structure that protects active hydrogen include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0067] Examples of dialkylaminolithium 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 pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithiazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0068] These organomonolithium compounds having substituted amino groups can also be used as solubilized oligomeric organomonolithium compounds by reacting small amounts of polymerizable monomers, such as 1,3-butadiene, isoprene, and styrene.

[0069] From the viewpoint of ease of industrial availability and ease of control of polymerization reactions, alkyllithium compounds are preferred as organic monolithium compounds. In this case, copolymers having an alkyl group at the polymerization initiation end can be obtained.

[0070] The alkyllithium compound is not limited to the following, but examples include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenilithium.

[0071] As the alkyllithium compounds, n-butyllithium and sec-butyllithium are preferred from the viewpoint of ease of industrial availability and ease of control of the polymerization reaction.

[0072] These organic monolithium compounds may be used individually or in combination of two or more. They may also be used in combination with other organometallic compounds.

[0073] Examples of the aforementioned other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0074] Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Compounds of alkaline earth metal alkoxides, sulfonates, carbonates, and amides are also included.

[0075] Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0076] In the polymerization process, the polymerization reaction mode is not limited to the following, but examples include batch mode (also called "batch reaction") and continuous polymerization reaction mode.

[0077] In a continuous reactor, one or more connected reactors can be used. Continuous reactors include, for example, tank-type or tubular-type reactors equipped with stirrers. Preferably, monomers, inert solvents, and polymerization initiators are continuously fed into the reactor, a polymer solution containing the polymer is obtained within the reactor, and the polymer solution is continuously discharged.

[0078] Batch reactors, for example, are tank-type reactors equipped with stirrers. In a batch reactor, monomers, an inert solvent, and a polymerization initiator are preferably fed into the reactor, and monomers are added continuously or intermittently during polymerization as needed, to obtain a polymer solution containing the polymer in the reactor, and the polymer solution is discharged after polymerization is complete.

[0079] In the method for producing conjugated diene polymers of this embodiment, a continuous process is preferred in order to obtain conjugated diene polymers having a high proportion of active ends, which allows for the continuous discharge of the polymer and its subsequent reaction in a short time.

[0080] In this embodiment, the polymerization step of the conjugated diene polymer is preferably carried out in an inert solvent. The inert solvent is not limited to the following, but examples include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not limited to the following, but examples include aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; and hydrocarbons consisting of aromatic hydrocarbons such as benzene, toluene, and xylene, and mixtures thereof.

[0081] Treating the impurities, such as allenes and acetylenes, with organometallic compounds before the polymerization reaction tends to yield conjugated diene polymers with a high concentration of active ends, and is therefore preferable because it tends to yield modified conjugated diene polymers with a high degree of modification.

[0082] In the polymerization process, polar substances (polar compounds) may be added. This allows for random copolymerization of aromatic vinyl compounds with conjugated diene compounds, and polar substances tend to be used as vinylizing agents to control the microstructure of the conjugated diene portion. They also tend to be effective in accelerating the polymerization reaction.

[0083] Examples of 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, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, and sodium amylate; and phosphine compounds such as triphenylphosphine. These polar substances may be used individually or in combination of two or more.

[0084] The amount of polar substance used is not particularly limited and can be selected according to the purpose, but it is preferable to use 0.01 moles or more and 30 moles or less per mole of polymerization initiator.

[0085] Such polar substances (vinylating agents) can be used in appropriate amounts depending on the desired amount of 1,2-vinyl bonds as modifiers of the microstructure of the conjugated diene moiety in conjugated diene polymers. Many polar substances also have an effective randomization effect in copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to be used as modifiers for adjusting the distribution of aromatic vinyl compounds and the amount of styrene block.

[0086] As a method for randomizing the conjugated diene compound and aromatic vinyl compound, for example, as described in Japanese Patent Publication No. 59-140211, a copolymerization reaction may be initiated with the entire amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene may be added intermittently during the copolymerization reaction.

[0087] Furthermore, from the viewpoint of increasing the reaction rate and improving productivity, the polymerization start temperature is preferably 25°C to 60°C, more preferably 25°C to 55°C, and even more preferably 25°C to 50°C. Also, from the viewpoint of increasing the polymerization addition rate of monomers, the polymerization end temperature is preferably 65°C or higher, more preferably 68°C or higher, and even more preferably 70°C or higher. On the other hand, from the viewpoint of increasing the denaturation rate, it is preferably 95°C or lower, more preferably 85°C or lower, even more preferably 82°C or lower, and particularly preferably 80°C or lower.

[0088] (Coupling process, modification process, hydrogenation process) The active ends of the conjugated diene polymer obtained through the polymerization process described above, and optionally a branching process using a predetermined branching agent, may be subjected to a coupling reaction using the aforementioned coupling agent or a modification reaction using a modification agent containing a nitrogen atom group. When a nitrogen atom-containing coupling agent is used, the coupling reaction and modification reaction proceed simultaneously. Furthermore, a hydrogenation step may be performed as appropriate.

[0089] (Inactivator addition process, neutralizing agent addition process) In the method for producing the conjugated diene polymer of this embodiment, a deactivator, neutralizing agent, etc., may be added to the polymer solution as needed.

[0090] Examples of inactivators include, but are not limited to, water; and alcohols such as methanol, ethanol, and isopropanol.

[0091] Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched mixture of carboxylic acids with 9 to 11 carbon atoms, mainly around 10); aqueous solutions of inorganic acids; and carbon dioxide.

[0092] (Desolvation process) In the method for producing the conjugated diene polymer of this embodiment, known methods can be used to obtain the conjugated diene polymer from the polymer solution. These methods are not limited to the following, but include, for example, a method in which the solvent is separated by steam stripping or the like, the polymer is filtered off, and then dehydrated and dried to obtain the polymer; a method in which the solution is concentrated in a flushing tank and then defolalated using a vent extruder or the like; and a method in which the solution is directly defolalated using a drum dryer or the like.

[0093] [Conjugated diene polymer composition] The conjugated diene polymer composition of this embodiment comprises a rubber component and a filler, wherein the rubber component comprises the conjugated diene polymer of this embodiment and the filler comprises carbon black. The conjugated diene polymer composition of this embodiment may contain other additives and rubber components described later.

[0094] The conjugated diene polymer composition of this embodiment preferably contains 10% by mass or more of the conjugated diene polymer of this embodiment described above, relative to the total amount of rubber components contained in the conjugated diene polymer composition (including the conjugated diene polymer of this embodiment described above).

[0095] The rubber component is not particularly limited, but may be natural rubber or synthetic rubber. If it is synthetic rubber, it may include, for example, isoprene rubber, butadiene rubber or its hydride, styrene-butadiene rubber or its hydride, nitrile rubber or its hydride, urethane rubber, butyl rubber or its halogenated compounds, ethylene-propylene-diene rubber (EPDM), chloroprene rubber, acrylic rubber, silicone rubber, and fluororubber.

[0096] The conjugated diene polymer composition of this embodiment preferably contains 10 parts by mass or more, and more preferably 15 parts by mass or more, of the filler per 100 parts by mass of the rubber component of this embodiment, from the viewpoint of rigidity and compression set. On the other hand, from the viewpoint of sufficiently dispersing the filler and making the processability and mechanical strength of the conjugated diene polymer composition of this embodiment practically sufficient, the filler content is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 200 parts by mass or less, and particularly preferably 100 parts by mass or less, per 100 parts by mass of the rubber component of this embodiment.

[0097] Examples of fillers include, but are not limited to, silica-based inorganic fillers, carbon black, calcium carbonate, titanium dioxide, aluminum hydroxide, and clay. These may be used individually or in combination of two or more. Furthermore, it may contain fillers other than those mentioned above. In this embodiment, using carbon black as the filler tends to exhibit more pronounced effects related to dynamic magnification and other aspects of this embodiment compared to using silica-based inorganic fillers. From the viewpoint of dynamic magnification and cost, the filler may consist solely of carbon black.

[0098] The filler used in the conjugated diene polymer composition of this embodiment preferably contains 40% by mass or more of carbon black, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, from the viewpoint of dynamic ratio.

[0099] The conjugated diene polymer composition of this embodiment, as an example, comprises 100 parts by mass of a rubber component and 10 to 300 parts by mass of a filler, wherein the rubber component may contain 10% by mass or more of the conjugated diene polymer of this embodiment described above, and the filler may contain 40% by mass or more of carbon black. Having such a composition is preferable because it can further improve rigidity, vibration damping properties, and thermal stability.

[0100] The silica-based inorganic filler is not limited to the following and any known fillers can be used, but for example, solid particles containing SiO2 or Si3Al as constituent units are preferred, and solid particles containing SiO2 or Si3Al as the main component of the constituent units are more preferred. Here, the main component refers to a component that is contained in the silica-based inorganic filler at a concentration of 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0101] Specific examples of silica-based inorganic fillers include, but are not limited to, silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fibers, and other inorganic fibrous materials.

[0102] Other examples include silica-based inorganic fillers with hydrophobic surfaces, and mixtures of silica-based inorganic fillers and non-silica-based inorganic fillers.

[0103] Among these, silica and glass fibers are preferred from the viewpoint of strength and abrasion resistance, with silica being more preferred. Examples of silica include dry silica, wet silica, and synthetic silicate silica.

[0104] Carbon black is not limited to the following, but examples include carbon blacks of various classes such as SRF, FEF, HAF, ISAF, and SAF. Among these, those with a nitrogen adsorption specific surface area of ​​50 m² are particularly noteworthy. 2 Carbon black with a concentration of 1 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0105] While not particularly limited, examples of calcium carbonate include calcium carbonate with an average particle size of 0.04 μm to 8.0 μm and an oil absorption capacity of 10 to 35 g per 100 g of calcium carbonate.

[0106] Furthermore, the filler may include other fillers besides those mentioned above. Examples of these other fillers include metal oxides and metal hydroxides. Metal oxides are those with the chemical formula M xO y This refers to solid particles whose main constituent unit is (where M represents a metal atom, and x and y each independently represent integers from 1 to 6).

[0107] Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0108] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0109] The conjugated diene polymer composition of this embodiment may contain a silane coupling agent.

[0110] Silane coupling agents have the function of strengthening the interaction between the rubber component and the inorganic filler, and possess groups that have affinity or binding properties to both the rubber component and the silica-based inorganic filler, respectively. Compounds having a sulfur bond portion and an alkoxysilyl group or silanol group portion in a single molecule are preferred.

[0111] Examples of such compounds, but not limited to the following, include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0112] In the conjugated diene polymer composition of this embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass to 30 parts by mass, more preferably 0.5 parts by mass to 20 parts by mass, and even more preferably 1.0 part by mass to 15 parts by mass, based on 100 parts by mass of the inorganic filler described above. When the content of the silane coupling agent is within the above range, the above-mentioned additive effect of the silane coupling agent tends to be made even more pronounced.

[0113] (Rubber softener) The conjugated diene polymer composition of this embodiment may optionally contain a rubber softener.

[0114] Rubber softeners are preferably added from the viewpoint of further improving the productivity of conjugated diene polymers and the processability of conjugated diene polymer compositions containing fillers, etc.

[0115] Examples of rubber softeners include, but are not limited to, stretching oils, liquid rubber, and resins.

[0116] While not limited to the following, a preferred method for adding a rubber softener to a conjugated diene polymer or conjugated diene polymer composition is to add the rubber softener to a conjugated diene polymer solution, mix it, obtain a polymer solution containing the rubber softener, and then desolvate the resulting solution.

[0117] Examples of the aforementioned spreading oils include aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils with a polycyclic aromatic (PCA) component content of 3% by mass or less according to the IP346 method are preferred from the viewpoint of environmental safety, as well as from the viewpoint of preventing oil bleeding and wet grip characteristics. Examples of aromatic substitute oils include TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999), as well as RAE (Residual Aromatic Extracts).

[0118] The liquid rubber mentioned above is not limited to the following, but examples include liquid polybutadiene and liquid styrene-butazine rubber.

[0119] The effects of adding liquid rubber include improving the processability of a conjugated diene polymer composition when it is compounded with a filler, and also shifting the glass transition temperature of the conjugated diene polymer composition (rubber composition) to a lower temperature, thereby improving the wear resistance and low-temperature properties of the vulcanized product.

[0120] The aforementioned resins are not limited to the following, but include, for example, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), 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, monoolefin oligomers, diolefin oligomers, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols.

[0121] These resins may be used individually or in combination of two or more. When hydrogenating, all unsaturated groups may be hydrogenated, or some may be left intact.

[0122] The effects of adding resin include improving the processability of the conjugated diene polymer composition (rubber composition) obtained by blending the conjugated diene polymer of this embodiment with fillers, improving the fracture strength when it becomes a vulcanized product, and shifting the glass transition temperature of the conjugated diene polymer composition of this embodiment to the higher temperature side, thereby improving the tensile properties at high temperatures.

[0123] The amount of rubber softener added, such as a stretching oil, liquid rubber, or resin, is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the conjugated diene polymer of this embodiment.

[0124] When a rubber softener is added within the aforementioned range, the processability of the conjugated diene polymer composition, which is a compound of the conjugated diene polymer in this actual form and fillers, etc., tends to improve, and the fracture strength and abrasion resistance of the vulcanized product tend to improve.

[0125] (Rubber stabilizer) In the method for producing the conjugated diene polymer composition of this embodiment, it is preferable to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing.

[0126] In the method for producing the conjugated diene polymer crosslinked product of this embodiment, it is preferable to use a hindered phenol antioxidant as a rubber stabilizer.

[0127] In the conjugated diene polymer composition of this embodiment, from the viewpoint of preventing gelation due to heat generation during kneading, it is preferable to contain 0.55 parts by mass or more of a hindered phenol antioxidant per 100 parts by mass of the conjugated diene polymer, more preferably 0.60 parts by mass or more, and even more preferably 0.65 parts by mass or more. On the other hand, from the viewpoint of cost, it is preferable to contain 1.8 parts by mass or less, more preferably 1.5 parts by mass or less, and even more preferably 1.4 parts by mass or less.

[0128] Furthermore, hindered phenol antioxidants can be further classified into sulfur-containing hindered phenol antioxidants and sulfur-free hindered phenol antioxidants.

[0129] In the conjugated diene polymer composition of this embodiment, it is preferable to include 0.10 parts by mass or more, more preferably 0.15 parts by mass or more, more preferably 0.20 parts by mass or more, and even more preferably 0.25 parts by mass or more, of a sulfur-containing hindered phenol antioxidant per 100 parts by mass of the conjugated diene polymer, from the viewpoint of suppressing gelation during kneading and suppressing oxidative degradation. On the other hand, from the viewpoint of odor, it is preferable to include 1.0 part by mass or less, more preferably 0.9 parts by mass or less, and even more preferably 0.8 parts by mass or less. Furthermore, per 100 parts by mass of the conjugated diene polymer, the sulfur-free hindered phenol antioxidant is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, more preferably 0.35 parts by mass or more, more preferably 0.4 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 0.6 parts by mass or more. On the other hand, from the viewpoint of coloration such as yellowing of the molded article, it is preferably 1.0 part by mass or less, more preferably 0.95 parts by mass or less, and even more preferably 0.9 parts by mass or less.

[0130] In the conjugated diene polymer composition of this embodiment, gelation due to heat generation during kneading can be verified by the method described in the examples.

[0131] To obtain a conjugated diene polymer composition that sufficiently reduces the risk of gelation and has excellent productivity, it is preferable to include 0.55 parts by mass to 1.8 parts by mass of a hindered phenol antioxidant per 100 parts by mass of the conjugated diene polymer, and it is even more preferable to include 0.1 parts by mass to 1.0 part by mass of a sulfur-containing hindered phenol antioxidant and 0.35 parts by mass to 1.0 part by mass of a sulfur-free hindered phenol antioxidant per 100 parts by mass of the conjugated diene polymer.

[0132] The aforementioned hindered phenol antioxidants may be used individually or in combination of two or more. Similarly, it is preferable to use one or more sulfur-containing hindered phenol antioxidants and one or more sulfur-free hindered phenol antioxidants in combination, and two or more of each may be used in combination.

[0133] The hindered phenol compound is not limited to the following, but examples include N-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, tetrakis{methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate}methane, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, distearyl(4-hydroxy-3-methyl-5-t-butylbenzyl)malonate, trie Tylene glycol-bis{3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate}, 1,6-hexanediol-bis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}, 2,4-bis-(N-octylthio)-6-(4-hydroxyphenyl)"3,5-di-t-butyl-anilino-1,3,5-triazine, 2,2-thiodiethylenebis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}, 2 ,2-thiobis(4-methyl-6-t-butylphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide], 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, bis(3,5-di- Examples include t-butyl-4-hydroxybenzyl) sulfide, tris(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 2,4-bis{(octylthio)methyl}-O-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-bis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionylhydrazine, and (meth)acrylate compounds having a hindered phenol structure.

[0134] (Molded body) The molded article of this embodiment contains the conjugated diene polymer composition of this embodiment. The molded article of this embodiment can be used in various applications, such as articles requiring dynamic magnification, but is particularly preferred for use in vibration-damping rubber. That is, the vibration-damping rubber of this embodiment contains the conjugated diene polymer composition of this embodiment. Specific examples of the molded article will be described below.

[0135] (Rubber bale molded body) The conjugated diene polymer of this embodiment can be formed into a rubber bale molded body.

[0136] A rubber bale molded body is a mass of a conjugated diene polymer or conjugated diene polymer composition obtained by compression molding. For example, it can be obtained by extruding a conjugated diene polymer composition with an extruder, cutting it to obtain crumbs, and then compression molding the crumbs.

[0137] (Conjugated diene polymer crosslinked product) The conjugated diene polymer composition of this embodiment may be a crosslinked composition obtained by crosslinking with a crosslinking agent.

[0138] Examples of crosslinking agents include, but are not limited to, organic peroxides and radical generators such as azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds.

[0139] Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high molecular weight polysulfur compounds.

[0140] In the conjugated diene polymer composition of this embodiment, the crosslinking agent content is preferably 0.01 parts by mass to 20 parts by mass, and more preferably 0.1 parts by mass to 15 parts by mass, per 100 parts by mass of the rubber component containing the conjugated diene polymer of this embodiment. Conventional known methods can be applied as the vulcanization method, and the vulcanization temperature is preferably 120°C to 200°C, and more preferably 140°C to 180°C.

[0141] During crosslinking, a vulcanization accelerator may be used as needed.

[0142] Conventional known materials can be used as vulcanization accelerators, and are not limited to the following, but include, for example, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, vulcanization aids are not limited to the following, but include, for example, zinc oxide, stearic acid, and triallyl isocyanurate.

[0143] The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component containing the conjugated diene polymer of this embodiment.

[0144] Organic peroxides include, but are not limited to, the following, examples: 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexine-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-butyl peroxide, tert-butyl peroxide Examples include p-menthane peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butyl peroxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy)perbenzoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, and tert-butylperoxyisopropyl carbonate.

[0145] The conjugated diene polymer crosslinked product of this embodiment can be used, for example, in tires, shoe soles, vibration-damping rubber and vibration-reducing materials, rubber belts, power transmission belts, conveyor belts, automobile interiors, hoses, industrial materials, and the like.

[0146] (Method for producing crosslinked conjugated diene polymers (rubber crosslinked products)) As a pretreatment for obtaining the conjugated diene polymer crosslinked product of this embodiment, the method for mixing various additives with the conjugated diene polymer is not limited to the following, but examples include a melt-kneading method using a general mixer such as an open roll, Banbury mixer, kneader, single-screw extruder, twin-screw extruder, or multi-screw extruder, and a method in which the solvent is removed by heating after dissolving and mixing each component.

[0147] Of these methods, melt-kneading methods using rolls, Banbury mixers, kneaders, and extruders are preferred from the viewpoint of productivity and good kneading performance. Furthermore, both methods of kneading the rubber components with other fillers, silane coupling agents, and additives in a single step, or methods of mixing in multiple steps, are applicable.

[0148] It is preferable to obtain a conjugated diene polymer crosslinked product by carrying out the aforementioned crosslinking reaction after the above mixing step.

[0149] (Other additives) The conjugated diene polymer composition (rubber composition) of this embodiment may contain various additives other than those mentioned above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, lubricants, and tackifiers, to the extent that the objective of this embodiment is not impaired.

[0150] Other known softening agents can be used.

[0151] For the heat-resistant stabilizer, antistatic agent, weather-resistant stabilizer, anti-aging agent, colorant, and lubricant mentioned above, known materials can be used. [Examples]

[0152] The embodiment will be described in more detail below with reference to specific examples and comparative examples, application examples and application comparative examples. However, this embodiment is not limited in any way to the following examples and comparative examples, application examples and application comparative examples.

[0153] Here, specific examples of conjugated diene polymers are referred to as "Examples" and "Comparative Examples," and specific examples of conjugated diene polymer compositions are referred to as "Application Examples" and "Application Comparative Examples." The various physical properties of the Examples and Comparative Examples, and the Application Examples and Application Comparative Examples were measured by the methods described below.

[0154] [Physical property measurement method] [Styrene content and vinyl bond content of conjugated diene polymers] As samples, we used conjugated diene polymers (polymers 1-7 described later), 1 The styrene content and vinyl bond amount (1,2-vinyl bond amount) were measured by 1H-NMR.

[0155] 1 The conditions for H-NMR measurement are described below. <Measurement conditions> Measuring instrument: JNM-LA400 (manufactured by JEOL) Solvent: Deuterated chloroform Measurement sample: Conjugated diene polymer Sample concentration: 50 mg / mL Observation frequency: 400MHz Chemical shift standard: Contains 0.05% by mass of TMS (tetramethylsilane) relative to deuterated chloroform. Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0156] [Styrene block content] The aromatic vinyl monomer block (styrene block) content was measured according to the osmium tetroxide decomposition method described in IMKolthoff, et al., J. Polym. Sci. 1, 429 (1946). More specifically, 0.050 g of a conjugated diene polymer was dissolved in 10 mL of chloroform, and 16 mL of a 69% by mass aqueous solution of tert-butyl hydroperoxide and 4.0 mL of a 0.050% by mass chloroform solution of osmium tetroxide were added. The reaction was carried out under reflux in a 90°C bath for 12 minutes to oxidative decomposition. After the reaction was complete, the reaction solution was cooled, and 200 mL of methanol was added to the reaction solution while stirring to precipitate the styrene block component, which was then filtered off through a 5 μm glass filter. The styrene block content was determined by dividing the mass of the obtained material by the total mass of the conjugated diene polymer.

[0157] [Weight-average molecular weight and coupling rate] A GPC analyzer consisting of three columns packed with polystyrene gel was used to measure chromatograms, and the peak-top molecular weight of each peak was determined based on a calibration curve using standard polystyrene. In the resulting molecular weight distribution curve, the peak with the largest peak area was designated as peak (a), and the peak with the highest molecular weight excluding peak (a) was designated as peak (b). The area ratio of peak (b) to the total peaks was defined as the coupling rate.

[0158] The specific measurement conditions are shown below. The following 20 μL of measurement solution was injected into the GPC measuring device and measurements were performed. (Measurement conditions) Device: Tosoh Corporation product name "HLC-8320GPC" Eluent: 5 mmol / L tetrahydrofuran (THF) containing triethylamine Guard column: Product name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation. Separation column: A combination of TSKgel SuperH5000, TSKgel SuperH6000, and TSKgel SuperH7000, manufactured by Tosoh Corporation, linked together in that order. Oven temperature: 40℃ Flow rate: 0.6mL / min Detector: RI detector (product name "HLC8020" manufactured by Tosoh Corporation) Measurement solution: A measurement solution prepared by dissolving 10 mg of the sample in 20 mL of THF.

[0159] [Degradation rate of conjugated diene polymers] The denaturation rate was measured using the column adsorption GPC method, taking advantage of the property that denatured polymers adsorb to a column, as follows: The amount adsorbed onto the silica column was determined by the difference between the chromatogram measured on a column packed with polystyrene gel and the chromatogram measured on a column packed with silica gel, and the amount adsorbed onto the silica column was determined by the difference between these two chromatograms, and the denaturation rate was determined by the difference between these two chromatograms.

[0160] (GPC measurement using polystyrene columns) The GPC measurement conditions using a polystyrene column are shown below. 20 μL of the measurement solution listed below was injected into the GPC measuring device and the measurement was performed. Device: Tosoh Corporation product name "HLC-8320GPC" Eluent: THF containing 5 mmol / L triethylamine Guard column: Product name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation. Column: A combination of the product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" manufactured by Tosoh Corporation, in that order. Oven temperature: 40℃ Flow rate: 0.6mL / min Detector: RI detector (Tosoh Corporation HLC8020) Measurement solution: 10 mg of the sample and 10 mg of standard polystyrene were dissolved in 20 mL of THF to prepare the sample solution.

[0161] (GPC measurement using silica-based columns) The GPC measurement conditions using a silica-based column are shown below. 50 μL of the measurement solution listed below was injected into the GPC measuring device and the measurement was performed. Device: Tosoh Corporation product name "HLC-8320GPC" Eluent:THF Guard column: DIOL 4.6×12.5mm 5micron, manufactured by GL Sciences Co., Ltd. Separation column: Agilent Technologies' Zorbax PSM-1000S, PSM-300S, and PSM-60S columns linked together in that order. Oven temperature: 40℃ Flow rate: 0.5mL / min Detector: RI detector (Tosoh Corporation HLC8020) Measurement solution: 10 mg of the sample and 10 mg of standard polystyrene were dissolved in 20 mL of THF to prepare the sample solution.

[0162] [Total Degeneration Rate] The denaturation rate (%) was calculated using the following formula, with the total peak area of ​​the chromatogram using a polystyrene column set to 100, the peak area of ​​the sample being P1, and the peak area of ​​standard polystyrene being P2. The total peak area of ​​the chromatogram using a silica column was also set to 100, with the peak area of ​​the sample being P3 and the peak area of ​​standard polystyrene being P4. The denaturation rate calculated in this way was defined as the total denaturation rate. Degeneration rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100 (However, P1+P2=P3+P4=100)

[0163] [Degeneration rate of uncoupled portion] Using the total degeneration rate and coupling rate obtained above, the degeneration rate (%) of the uncoupled portion was calculated using the following formula. Uncoupled portion degeneration rate (%) = (Total degeneration rate) - (Coupling rate)

[0164] [R1 - Area reduction rate for the entire GPC peak] The area reduction rate R1 was measured for polymers 1 to 7, described below. First, polymers 1 to 7 were subjected to GPC measurement before performing the following operation (i). The area value of all peaks in the obtained molecular weight distribution curve D1 was defined as C1. Next, the extracts obtained after performing operation (i) on polymers 1 to 7 were subjected to GPC measurement. The area value of all peaks in the obtained molecular weight distribution curve D2 was defined as C2. Based on the area values ​​C1 and C2, the peak area reduction rate R1 was calculated from 100 × (C1 - C2) / C1. The GPC measurement of the extracts was performed using GPC with the polystyrene column described above. (Operation (i)) 1. A compound was obtained by adding 50 parts of carbon black to 100 parts of polymer. 2. The obtained compound was finely chopped into cubes with sides of 1.5-2.0 mm, and 0.25 g was added to a sample tube. Then, 50 mL of toluene was added to the sample tube, and it was immersed at 25°C for 1 day. After immersion for 1 day, it was confirmed that the compound had separated into a toluene-insoluble portion and a toluene-soluble portion. The portion dissolved in toluene was used as the filtrate. 3. The filtrate portion was recovered by vacuum filtration using filter paper (circular glass fiber filter paper "GF / B" (manufactured by Cytiva)), toluene was evaporated, and the resulting precipitate was dissolved with tetrahydrofuran (THF) to obtain an extract.

[0165] [Area reduction rate R2 for GPC peak (A), area reduction rate R3 for GPC peak (B)] Of all the peaks in the molecular weight distribution curve D1 obtained above, the peak with the largest peak area was designated as peak (A1). Similarly, of all the peaks in the molecular weight distribution curve D2 obtained above, the peak with the largest peak area was designated as peak (A2). The peak area reduction rate R2 was calculated as 100 × (A1 - A2) / A1. Of all peaks in the molecular weight distribution curve D1 obtained above, the peak located on the highest molecular weight side excluding peak (A1) was designated as peak (B1). Of all peaks in the molecular weight distribution curve D2 obtained above, the peak located on the highest molecular weight side excluding peak (A2) was designated as peak (B2). The peak area reduction rate R3 was calculated as 100×(B1-B2) / B1. In the table, for polymers in which peak (B1) does not exist, the area reduction rate R3 is indicated as "-".

[0166] 〔Mooney Viscosity〕 Using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.), the Mooney viscosity and Mooney stress relaxation of each polymer were measured in accordance with JIS K6300 (ISO289-1) and ISO289-4. The measurement temperature was set to 100°C. Here, after preheating the sample for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured and defined as the Mooney viscosity (ML).

[0167] 〔Silicon Content, Tin Content〕 The conjugated diene-based polymer obtained in the polymerization examples described later was subjected to elemental analysis using an inductively coupled plasma (ICP, Inductively Coupled Plasma, manufactured by Shimadzu Corporation, apparatus name: ICPS-8100) to measure the silicon content (unit: ppm) and tin content (unit: ppm) in the polymer, and the total content was calculated.

[0168] 〔Evaluation of Cold Flow Property〕 A measurement sample cut out to dimensions of 40 mm × 40 mm × thickness (H0) 50 mm from Polymers 1 to 7 (polymers obtained as bales) described later was subjected to a load of 1 kg at 25°C, and the thickness (H 60 ) after being left for 120 minutes was used to calculate the thickness change rate (%) by the following formula. Thickness change rate (%) = (H0-H 60 ) × 100 / H0 When the thickness change rate is 60% or less, it was rated as ○ since there is no practical problem, and when it exceeds 60%, it was rated as × because the cold flow during storage is severe and the handleability is poor.

[0169] [Production of conjugated diene polymers] (Example 1; Polymer 1) As shown in Table 1, a temperature-controlled autoclave with an internal volume of 40 L, equipped with a stirrer and jacket, was used as the reactor. 120 g of styrene, 21,000 g of cyclohexane, and 0.19 mol of THF as a polar substance were added to the reactor, and the reactor temperature was maintained at 50°C. As a polymerization initiator, 19.20 mmol of n-butyllithium was supplied to the reactor. After the polymerization reaction began, the temperature inside the reactor rose due to the heat generated by polymerization. Five minutes after the reactor temperature reached 52°C, 2,880 g of 1,3-butadiene, from which impurities had been removed beforehand, was supplied. The final temperature inside the reactor was 81°C. To this polymer solution, 14.05 mmol of 1,3-dimethyl-2-imidazolidinone (compound 1) was added as a denaturing agent, and the mixture was reacted for 10 minutes. Then, 15 moles of water were added as a reaction stopper. To the obtained polymer solution, 24.0 g of stabilizer 1 (n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate) and 12.0 g of stabilizer 2 (4,6-bis(octylthiomethyl)-o-cresol) were added as antioxidants. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain polymer 2. Table 2 shows the analysis results obtained by analyzing the obtained polymer 1 using the method described above.

[0170] (Comparative Example 1; Polymer 4) As shown in Table 1, a conjugated diene polymer (polymer 4) was obtained in the same manner as in Example 1, except that the amount of styrene added was changed. After adding the stabilizers listed in Tables 1 and 2 to the respective solutions of the obtained conjugated diene polymers, the solvent was removed by dropping the respective conjugated diene polymer solutions into warm water, and the solutions were dried in a drying oven to obtain the conjugated diene polymer (polymer 4) compositions. Table 2 shows the analysis results obtained by analyzing the obtained polymer 4 using the method described above.

[0171] [Production of conjugated diene polymers] (Example 2; Polymer 2) As shown in Table 1, a temperature-controlled autoclave with an internal volume of 40 L, equipped with a stirrer and jacket, was used as the reactor. 3,000 g of 1,3-butadiene, 21,000 g of cyclohexane, and 0.14 mol of THF as a polar substance were added to the reactor, and the reactor temperature was maintained at 50°C. As a polymerization initiator, 14.05 mmol of n-butyllithium was supplied to the reactor. The polymerization reaction was carried out in the same manner as in Example 1 until the peak temperature was reached after the start of the polymerization reaction. Once the peak temperature was reached, 0.42 mmol of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (hereinafter also referred to as "compound 2") was added to the polymer solution as a denaturing agent, and the reaction was allowed to proceed for 5 minutes. Then, 14.05 mmol of compound 1 was added, and the reaction was allowed to proceed for 10 minutes. After that, 15 moles of water was added as a reaction stopper. To the obtained polymer solution, 24.0 g of stabilizer 1 and 12.0 g of stabilizer 2 were added as antioxidants. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain polymer 2. Table 2 shows the analysis results obtained by analyzing the obtained polymer 2 using the method described above.

[0172] (Examples 3 and Comparative Examples 2-4; Polymers 3, 5, 6, 7) As shown in Tables 1 and 2, each conjugated diene polymer (polymers 3, 5, 6, and 7) was obtained in the same manner as in Example 1, except that the type and / or amount of the modifying agent was changed. After adding the stabilizers listed in Tables 1 and 2 to the solutions of each obtained conjugated diene polymer, the solvent was removed by dropping the respective conjugated diene polymer solutions into warm water, and the solutions were dried in a drying oven to obtain the conjugated diene polymer (polymers 3, 5, 6, and 7) compositions.

[0173] [Table 1]

[0174] The symbols in Table 1 are explained below. Compound 3: Tin tetrachloride Compound 4: Tetramethoxysilane

[0175] [Table 2]

[0176] [Application Examples 1-4, Comparative Examples 1-6] The raw rubber components used were natural rubber and butadiene rubber. RSS#3 was used as the natural rubber, and conjugated diene polymers 1 to 8 shown in Table 3 or high-cis butadiene rubber (UBE Corporation, UBEPOL BR150; a polymer in which the peak area reduction rate R1 does not satisfy 60% or more) were used as the butadiene rubber. Conjugated diene polymer compositions containing each raw rubber were obtained according to the formulations shown below.

[0177] (Conjugated diene polymer composition) The following materials were prepared. Natural rubber (RSS#3): 60.0 parts by mass Butadiene rubber (conjugated diene polymers 1-8 or high-cis butadiene rubber): 40.0 parts by mass Filler (carbon black, or silica and silane coupling agent): 50 parts • Carbon black (manufactured by Tokai Carbon Co., Ltd., C-ST SO (N550)) • Silica (manufactured by Evonik and Degussa, product name "Ultrasil 7000GR") • Silane coupling agent (Evonik brand name "Si75", bis(triethoxysilylpropyl) disulfide) Naphthenic oil (manufactured by Idemitsu Kosan Co., Ltd., Diana Process NM-280): 10.0 parts by mass Zinc white: 5.0 parts by mass Stearic acid: 1.0 part by mass Anti-aging agent (Nocrac 6C): 2.0 parts by mass Anti-aging agent (Nocrac MB): 1.0 parts by mass Wax (manufactured by Ouchi Shinko Chemical Co., Ltd., Sunnock N): 2.0 parts by mass Sulfur: 2.5 parts by mass Vulcanization accelerator (N-(tert-butyl)-2-benzothiazole sulfenamide): 1.5 parts by mass (For Application Example 1, the total is 175.0 parts by mass. The formulation amounts for other examples are shown in Table 3.)

[0178] The above materials were kneaded by the following method to obtain a conjugated diene polymer composition. Using a sealed kneader (capacity 0.3L) equipped with a temperature control device, the first stage of kneading involved mixing raw rubber, filler, oil (naphthenic oil), wax (Sunnock N), zinc oxide, stearic acid, and antioxidants (Nocrack 6C, Nocrack MB) under conditions of a filling rate of 65% and a rotor rotation speed of 50 / 57 rpm. During this process, the temperature of the sealed mixer was controlled, and a conjugated diene polymer composition was obtained at a discharge temperature (compound) of 150°C. After cooling, the mixture was kneaded in the second stage using an open roll oven set to 70°C, with sulfur and a vulcanization accelerator added. Subsequently, 2mm thick and 3mm thick sheets were molded and vulcanized in a vulcanizing press at 160°C for 20 minutes. For this purpose, test samples for evaluating tensile properties were prepared by punching out test pieces from a 2mm thick vulcanized sheet using a die-cutting machine. For evaluation of compression set and dynamic magnification, test samples were vulcanized using a mold so that each sample had a diameter of 29 mm and a thickness of 12.6 mm.

[0179] ((1) Tensile properties) The tensile strength and elongation of the aforementioned test samples at 23°C were measured according to the tensile test method of JIS K6251. The product of the tensile strength and elongation at 23°C was defined as the tensile property. Higher tensile properties are preferable. Table 3 shows the relative values ​​when the measured value of Application Comparative Example 6 is set to 100. A higher relative value is considered better.

[0180] ((2) Dynamic magnification) In accordance with JIS K6385, the static spring constant and dynamic spring constant of the test samples described above were measured, and the dynamic ratio (dynamic spring constant / static spring constant) was calculated. The measuring instrument used was the ACUMEN3 manufactured by MTS. A lower dynamic magnification value indicates better performance. Table 3 shows the relative values ​​when the measured value of Application Comparison Example 6 is set to 100. A higher relative value is considered better.

[0181] ((3) Compression set) In accordance with JIS K6262, the compression set of the above-mentioned test samples was measured after heating them at 100°C for 24 hours. A smaller compression set value indicates better performance. Table 3 shows the relative values ​​when the measured value for Application Comparison Example 6 is set to 100. A higher relative value is considered better.

[0182] [Table 3] [Industrial applicability]

[0183] The conjugated diene polymers and conjugated diene polymer compositions of this embodiment have industrial applicability as vibration-damping rubber, vibration-reducing rubber materials, vibration-isolated rubber, tires, packings and gaskets, sealing materials, conveyor belts, transmission belts, shoe outsoles and shoe midsoles, automobile weatherstrips, glass runs, trunk lids, railway vehicle components, aircraft components, waterproof sheets, engine mounts, motor mounts, industrial hoses, air springs, rubber gloves, medical and hygiene products, industrial and various application hoses, battery cases, adhesives, wire insulation, window frame rubber, rubber rolls, rubber rollers for office automation equipment and textiles, keypads, keyboard covers, swimming goggles, swimming caps, container bags, marine-related parts, interior flooring materials, artificial muscle materials, other vibration-reducing materials, and materials for various industrial products.

Claims

1. A conjugated diene polymer having structural units derived from a conjugated diene compound, The aromatic vinyl monomer unit content is 5% by mass or less. The amount of 1,2-vinyl bonding is 10 mol% or more and 22 mol% or less. The denaturation rate is 50% by mass or more and 99% by mass or less. The silicon content is 50 ppm or less. A conjugated diene polymer in which the peak area reduction rate R1, calculated from the area value C1 of all peaks in the molecular weight distribution curve D1 obtained by subjecting the conjugated diene polymer to gel permeation chromatography (GPC) measurement before performing the following operation (i), and the area value C2 of all peaks in the molecular weight distribution curve D2 obtained by subjecting the extract obtained after performing the operation (i) on the conjugated diene polymer to GPC measurement, is 60% or more and 99% or less, with R1 being 100 × (C1 - C2) / C1. (Operation (i)) To 100 parts of the conjugated diene polymer, 50 parts of carbon black are added to obtain a compound. The compound is immersed in toluene at 25°C for one day. After the immersion, the portion of the conjugated diene polymer dissolved in toluene is recovered by vacuum filtration, the toluene is evaporated, and the resulting precipitate is dissolved in tetrahydrofuran to obtain an extract.

2. The conjugated diene polymer according to claim 1, wherein in the molecular weight distribution curve D1, there are two or more peaks with a peak area of ​​5% or more.

3. The conjugated diene polymer according to claim 2, wherein when the peak with the largest peak area among all peaks in the molecular weight distribution curve D1 is defined as peak (A1), and the peak with the largest peak area among all peaks in the molecular weight distribution curve D2 is defined as peak (A2), the peak area reduction rate R2 is 70% or more and 99% or less, calculated as 100 × (A1 - A2) / A1.

4. Of all the peaks in the molecular weight distribution curve D1, peak (A1) is the peak on the lowest molecular weight side. The conjugated diene polymer according to claim 3, wherein, among all the peaks in the molecular weight distribution curve D2, peak (A2) is the peak on the lowest molecular weight side.

5. The conjugated diene polymer according to claim 3, wherein, among all the peaks in the molecular weight distribution curve D1, the peak furthest toward the polymer excluding peak (A1) is defined as peak (B1), and among all the peaks in the molecular weight distribution curve D2, the peak furthest toward the polymer excluding peak (A2) is defined as peak (B2), and the value of the peak area reduction rate R3 calculated as 100 × (B1 - B2) / B1 is less than or equal to the value of the peak area reduction rate R2.

6. The conjugated diene polymer according to claim 5, wherein the peak area reduction rate R3 is 50% or more and 99% or less.

7. The conjugated diene polymer according to claim 1, wherein the coupling rate is 7% by mass or more and 15% by mass or less.

8. The conjugated diene polymer according to claim 1, wherein the uncoupled partial modification rate is 50% by mass or more and 99% by mass or less.

9. The conjugated diene polymer according to claim 1, wherein the tin content is 20 ppm or less.

10. The conjugated diene polymer according to claim 1, wherein the Mooney viscosity at 100°C is 35 or more and 130 or less.

11. Rubber components, Filler and, Includes, The rubber component comprises a conjugated diene polymer according to any one of claims 1 to 10. The filler is a conjugated diene polymer composition containing carbon black.

12. The amount of filler per 100 parts by mass of the rubber component is 10 parts by mass or more and 300 parts by mass or less. The conjugated diene polymer composition according to claim 11, wherein 10% by mass or more of the rubber component is the conjugated diene polymer.

13. The conjugated diene polymer composition according to claim 11, wherein 90% by mass or more of the filler is carbon black.

14. Vibration-damping rubber comprising the conjugated diene polymer composition described in claim 11.

15. A molded article comprising the conjugated diene polymer composition described in claim 11.

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