Modified conjugated diene polymers, methods for producing modified conjugated diene polymers, and compositions of modified conjugated diene polymers and rubber compositions.

Abstract

To provide a modified conjugated diene-based polymer that is excellent in form retainability and also excellent in the abrasion resistance, fracture performance and low hysteresis loss of a vulcanizate obtained therefrom, and a method for producing the same, and a modified conjugated diene-based polymer composition and a rubber composition each of which includes the modified conjugated diene-based polymer.SOLUTION: A modified conjugated diene-based polymer comprises a nitrogen atom and a silicon atom, wherein a Mooney viscosity measured at 100°C is 100 or more and 150 or less, a Mooney stress relaxation rate measured at 100°C is 0.40 or more and 0.70 or less, a glass transition temperature Tg is -90°C to -40°C, and a phase difference index measured at 160°C and 0.1 Hz is 0.65 or more and 1.10 or less, and both nitrogen content and silicon content are 50 ppm or more, based on mass, relative to the total amount of the modified conjugated diene-based polymer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a modified conjugated diene polymer, a method for producing a modified conjugated diene polymer, and a modified conjugated diene polymer composition, a rubber composition, and the like. [Background technology]

[0002] In recent years, there has been a growing demand for improved fuel efficiency in automobiles, which has led to a need for improvements in the rubber materials used in automobile tires, particularly in the tire treads that come into contact with the road surface.

[0003] Furthermore, due to increasing fuel efficiency regulations for automobiles, there is a growing demand for the use of resin in automobile components and thinner tires, with the aim of reducing the weight of automobiles.

[0004] When making tires thinner, it is necessary to reduce the thickness of the tread, which accounts for a large proportion of the tire's overall thickness and is in contact with the road surface. This necessitates rubber materials with even greater wear resistance than before.

[0005] Furthermore, in order to reduce energy loss caused by the tires during driving, the rubber material used for the tread is preferably a material with low rolling resistance, i.e., low hysteresis loss.

[0006] Furthermore, tire materials are required to have sufficient fracture strength for practical use from a safety standpoint.

[0007] Examples of rubber materials that meet the above-mentioned requirements include rubber compositions comprising a rubbery polymer and reinforcing fillers such as carbon black and silica.

[0008] In such rubber compositions, attempts have been made to improve the dispersibility of silica in the rubber composition and reduce the mobility of the molecular ends of the rubbery polymer, thereby reducing hysteresis loss and improving abrasion resistance and fracture strength, by introducing functional groups that have affinity or reactivity with silica at the molecular ends of the highly mobile rubbery polymer.

[0009] For example, Patent Documents 1 to 3 disclose compositions of a modified conjugated diene polymer obtained by reacting amino group-containing alkoxysilanes with the active end of a conjugated diene polymer, and silica. Patent Document 4 also discloses a composition of a modified conjugated diene polymer and silica that improves hysteresis loss and wear resistance and has excellent processability. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2005-290355 [Patent Document 2] Japanese Patent Application Publication No. 11-189616 [Patent Document 3] Japanese Patent Publication No. 2003-171418 [Patent Document 4] International Publication No. 2020 / 013638 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, when the present inventors examined conventional rubber compositions, including those described in Patent Documents 1 to 4, in detail, they found that conventional rubber compositions have insufficient physical properties. For example, reducing the molecular weight of a modified conjugated diene polymer increases the number of functional groups that have affinity and reactivity with silica, improving the dispersion of silica. However, when such materials are vulcanized, especially when they are vulcanized products containing inorganic fillers such as silica, their tensile strength and abrasion resistance are insufficient.

[0012] Furthermore, a decrease in the molecular weight of the modified conjugated diene polymer impairs its moldability, making it more susceptible to so-called cold flow. Modified conjugated diene copolymers used in tire materials are generally handled in bale form, but deformation during transportation after production can lead to a decrease in tire productivity.

[0013] Therefore, the present invention has been made in view of the above problems, and aims to provide a modified conjugated diene polymer that has excellent mold retention properties and whose vulcanized product has excellent abrasion resistance, fracture properties and low hysteresis loss properties, a method for producing the same, and a modified conjugated diene polymer composition and rubber composition using the modified conjugated diene polymer. [Means for solving the problem]

[0014] As a result of diligent research and investigation to solve the above problems, the present inventors have found that a modified conjugated diene polymer having nitrogen content, silicon content, Mooney viscosity, Mooney relaxation rate, glass transition temperature, and phase difference index within predetermined ranges exhibits excellent mold retention, and its vulcanized product exhibits excellent wear resistance, fracture properties, and low hysteresis loss, thus completing the present invention. That is, the present invention is as follows.

[0015] [1] It contains nitrogen atoms and silicon atoms, The Mooney viscosity measured at 100°C is between 100 and 150, the Mooney relaxation rate measured at 100°C is between 0.40 and 0.70, the glass transition temperature Tg is between -90°C and -40°C, and the phase difference index measured at 160°C and 0.1 Hz is between 0.65 and 1.10. The nitrogen content and silicon content are 50 ppm or more each, based on mass relative to the total amount of the modified conjugated diene polymer. Modified conjugated diene polymers.

[0016] [2] It has a molecular weight distribution (Mw / Mn) of 1.5 or more and less than 2.5. [1] The modified conjugated diene polymer described above.

[0017] [3] The Mooney viscosity measured at 100°C is between 100 and 130. A modified conjugated diene polymer as described in [1] or [2].

[0018] [4] The Mooney relaxation rate measured at 100°C is 0.50 or more and 0.70 or less. A modified conjugated diene polymer as described in any one of the following items [1] to [3].

[0019] [5] The amount of vinyl bonds in the conjugated diene polymer is 15-43%. A modified conjugated diene polymer as described in any one of the items [1] to [4].

[0020] [6] A method for producing a modified conjugated diene polymer according to any one of items [1] to [5], The process involves using an organolithium compound as a polymerization initiator to polymerize at least a conjugated diene compound and an aromatic vinyl compound while reacting them with a coupling modifier to obtain a modified conjugated diene polymer. A method for producing modified conjugated diene polymers.

[0021] [7] 100 parts by mass of a modified conjugated diene polymer described in any one of items [1] to [5], A rubber softener of 1.0 part by mass or more and 60 parts by mass or less, Contains Modified conjugated diene polymer composition.

[0022] [8] A rubber component containing 50 parts by mass or more of a modified conjugated diene polymer described in any one of items [1] to [5], A filler in an amount of 5.0 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the rubber component, Contains Rubber composition. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a modified conjugated diene polymer that exhibits excellent mold retention properties and whose vulcanized product has excellent abrasion resistance, fracture properties, and low hysteresis loss, as well as a method for producing the same, and a modified conjugated diene polymer composition using the modified conjugated diene polymer, and a rubber composition, etc. [Modes for carrying out the invention]

[0024] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below. The following embodiments are illustrative examples for explaining the present invention, and the present invention is not limited thereto. That is, the present invention can be modified and implemented without departing from its essence. In this specification, when "~" is used to enclose numerical values ​​or physical properties, it is used to include the values ​​before and after it.

[0025] [Modified conjugated diene polymers] The modified conjugated diene polymer of this embodiment contains nitrogen atoms and silicon atoms, has a Mooney viscosity of 100 to 150 measured at 100°C, a Mooney relaxation rate of 0.40 to 0.70 measured at 100°C, a glass transition temperature Tg of -90°C to -40°C, and a phase difference index of 0.65 to 1.10 measured at 160°C and 0.1 Hz, with nitrogen content and silicon content of 50 ppm or more each on a mass basis relative to the total amount of the modified conjugated diene polymer.

[0026] (Conjugated diene compounds and aromatic vinyl compounds) The modified conjugated diene polymer of this embodiment is a copolymer of at least one conjugated diene compound and at least one aromatic vinyl compound. Hereafter, units derived from the conjugated diene compound in the copolymer will be referred to as conjugated diene units, and units derived from the aromatic vinyl compound in the copolymer will be referred to as aromatic vinyl units.

[0027] The conjugated diene compound is not particularly limited, but examples 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 effectively and reliably achieving the effects of this embodiment. These conjugated diene compounds may be used individually or in combination of two or more.

[0028] The aromatic vinyl compound is not particularly limited, but examples include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of effectively and reliably achieving the effects of this embodiment. These aromatic vinyl compounds may be used individually or in combination of two or more.

[0029] (Amount of bonded aromatic vinyl and amount of vinyl bonds in bonded conjugated dienes) In the microstructure of the modified conjugated diene polymer, the lower limit of the amount of bonded aromatic vinyl is not particularly limited, but is preferably 1% by mass, more preferably 2% by mass, even more preferably 3% by mass, and especially preferably 5% by mass, relative to the entire modified conjugated diene polymer. The upper limit of the amount of bonded aromatic vinyl is not particularly limited, but is preferably 22% by mass, more preferably 21% by mass, and even more preferably 20% by mass. For example, within the preferred range of vinyl bond amounts described later, when the amount of bonded aromatic vinyl is at the lower limit, a glass transition temperature of approximately -90°C to -67°C can be obtained, and when the amount of bonded aromatic vinyl is at the upper limit, a glass transition temperature of approximately -61°C to -40°C can be obtained. Therefore, when the amount of bonded aromatic vinyl is within the above range, the processability of the vulcanized product of the modified conjugated diene polymer tends to be further improved. The amount of bonded aromatic vinyl may be within a range arbitrarily combined from the above upper and lower limits, for example, it may be 1% by mass or more and 20% by mass or less. In this specification, "amount of bonded aromatic vinyl" means the amount of the portion derived from the aromatic vinyl compound relative to the entire modified conjugated diene polymer (for example, the amount of bonded styrene if the aromatic vinyl compound is styrene).

[0030] In the microstructure of the modified conjugated diene polymer, the amount of bonded conjugated diene is not particularly limited, but is preferably 78% to 99% by mass, more preferably 78% to 98% by mass, and even more preferably 79% to 95% by mass, relative to the entire modified conjugated diene polymer. When the amount of bonded conjugated diene is within the above range, the low-temperature properties of the vulcanized product of the modified conjugated diene polymer tend to be further enhanced. The amount of bonded conjugated diene may be 99% or less by mass, 98% or less by mass, 97% or less by mass, or 95% or less by mass, within the above range. The amount of bonded conjugated diene may also be 78% or more by mass, 79% or more by mass, or 80% or more by mass, within the above range. The amount of bonded conjugated diene may be within a range that is an arbitrary combination of the above upper and lower limits. In this specification, "amount of bonded conjugated diene" means the content of the portion derived from the conjugated diene compound relative to the entire modified conjugated diene polymer.

[0031] In the microstructure of the modified conjugated diene polymer, the amount of vinyl bonds in the bonded conjugated diene (hereinafter also simply referred to as "vinyl bond amount") is not particularly limited, but is preferably 15 mol% to 43 mol%, more preferably 16 mol% to 40 mol%, and even more preferably 17 mol% to 38 mol% relative to the total amount of bonded conjugated diene. For example, within the preferred range of bonded aromatic vinyl, when the bonded vinyl amount is at the lower limit, a glass transition temperature of approximately -90°C to -61°C can be obtained, and when the bonded vinyl amount is at the upper limit, a glass transition temperature of approximately -67°C to -40°C can be obtained. Therefore, when the vinyl bond amount is within the above range, the modified conjugated diene polymer tends to have excellent low-temperature properties because the amount of cis bonds in the bonded conjugated diene decreases and crystallization is inhibited. The vinyl bond amount may be within a range arbitrarily combined from the above upper and lower limits, for example, it may be 15 mol% to 40 mol%. In this specification, "amount of vinyl bonds in a conjugated diene" means the molar ratio of the portion of the conjugated diene compound (hereinafter referred to as "conjugated diene") that has vinyl bonds.

[0032] Here, the amount of bonded aromatic vinyl can be calculated by measuring the ultraviolet absorption of the aromatic group (e.g., phenyl group) of the unit derived from the aromatic vinyl compound of the modified conjugated diene polymer (hereinafter referred to as "bonded aromatic vinyl unit"). Furthermore, if the modified conjugated diene polymer consists of bonded aromatic vinyl units and bonded conjugated diene units, the amount of bonded conjugated diene can also be determined from the amount of bonded aromatic vinyl obtained as described above. Specifically, this can be measured by the method described in the examples below.

[0033] Furthermore, if the modified conjugated diene polymer is, for example, a copolymer of butadiene and styrene, the amount of vinyl bonds (1,2-bonds) in the bonded butadiene can be determined by Hampton's method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, this can be measured by the method described in the examples below.

[0034] In this embodiment, it is preferable that the modified conjugated diene polymer has a small number or no blocks in which 30 or more linked aromatic vinyl units are linked together. The content of blocks in which 30 or more linked aromatic vinyl units are linked together can be measured by known methods, such as, in the case of a butadiene-styrene copolymer, by decomposing the copolymer using the method of Kolthoff (as described in IMKOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)) and analyzing the amount of polystyrene insoluble in methanol. The content of blocks in which 30 or more linked aromatic vinyl units are linked together, as measured by such methods, is not particularly limited, but is preferably 5.0% by mass or less, and more preferably 3.0% by mass or less, relative to the total amount of the modified conjugated diene polymer. The lower limit is not particularly limited, but may be 0.0% by mass or more, but more preferably 0.0% by mass, relative to the total amount of the modified conjugated diene polymer.

[0035] In this embodiment, from the viewpoint of further improving fuel efficiency, it is preferable that the modified conjugated diene polymer has a high proportion of individually bonded aromatic vinyl units, that is, a low proportion of adjacent aromatic vinyl units. Specifically, for example, when the copolymer is a butadiene-styrene copolymer, when the copolymer is decomposed by Tanaka et al.'s method using ozonolysis (Polymer, 22, 1721 (1981)) and the bonded aromatic vinyl chain distribution (styrene chain distribution in this example) is analyzed by gel permeation chromatography (hereinafter also referred to as "GPC"), it is preferable that the amount of isolated aromatic vinyl (isolated styrene in this example) is 40% by mass or more of the total amount of bonded aromatic vinyl (bonded styrene in this example), and that the amount of chained aromatic vinyl structures (chained styrene structures in this example) with 8 or more aromatic vinyl (styrene in this example) chains is 5.0% by mass or less. Such modified conjugated diene polymers tend to have vulcanized products that exhibit even greater low hysteresis loss properties.

[0036] Furthermore, the amount of bonded aromatic vinyl, the amount of bonded conjugated diene, and the amount of vinyl bond all affect the glass transition temperature (hereinafter also referred to as "Tg") of the modified conjugated diene polymer. The glass transition temperature can be controlled by setting the amount of bonded aromatic vinyl to the above numerical range of 1% to 22% by mass, the amount of bonded conjugated diene to 78% to 99% by mass, and the amount of vinyl bond to 15 mol% to 43 mol%. Note that Tg tends to increase as the amount of bonded aromatic vinyl increases, and conversely, Tg tends to increase as the amount of bonded vinyl increases. When the amount of bonded aromatic vinyl is 1% or more by mass and the amount of vinyl bond is 15 mol%, Tg tends to be around -90°C. Also, for example, when the amount of bonded aromatic vinyl is 22% or more by mass and the amount of vinyl bond is 43 mol%, Tg tends to be around -40°C.

[0037] (Glass transition temperature) The glass transition temperature (Tg) of the modified conjugated diene polymer in this embodiment is not particularly limited, but is preferably -90°C or higher, and more preferably -80°C or higher. Furthermore, the glass transition temperature is preferably -40°C or lower, and more preferably -43°C or lower. When the glass transition temperature is within the above range, the wear resistance and low hysteresis loss properties of the vulcanized product of the modified conjugated diene polymer tend to be even better. The glass transition temperature may be within a range arbitrarily obtained by combining the above upper and lower limits. The glass transition temperature of the modified conjugated diene polymer and the modified conjugated diene polymer are measured according to ISO 22768:2017. More specifically, differential scanning calorimetry (DSC) measurement is performed while increasing the temperature within a predetermined temperature range, and the DSC curve is recorded. The peak top (inflection point) of the obtained DSC differential curve is defined as the glass transition temperature. Specifically, it can be measured by the method described in the examples below.

[0038] (average molecular weight) The weight-average molecular weight (Mw) of the modified conjugated diene polymer of this embodiment, as measured by GPC, is not particularly limited, but is preferably 30 × 10⁻⁶. 4 That is all, more preferably 40 × 10 4or more, more preferably 45×10 4 or more, particularly preferably 50×10 4 or more. When the weight-average molecular weight measured by the GPC measurement method is within the above range, the fracture properties and abrasion resistance tend to be excellent. Further, the weight-average molecular weight is not particularly limited, but is preferably 150×10 4 or less, more preferably 100×10 4 or less, still more preferably 80×10 4 or less, particularly preferably 70×10 4 or less. When the weight-average molecular weight is within the above range, the dispersibility of the filler in the vulcanizate is further excellent, and practical fracture properties tend to be obtained. The above weight-average molecular weight may be within a range arbitrarily combining the above upper limit value and lower limit value. The weight-average molecular weight measured by the GPC measurement method of the modified conjugated diene polymer and the modified conjugated diene polymer described later is specifically measured by the method described in the examples described later.

[0039] The number-average molecular weight (Mn) measured by the GPC measurement method of the modified conjugated diene polymer of the present embodiment is not particularly limited, but is preferably 15×10 4 or more, more preferably 20×10 4 or more, still more preferably 25×1o 4 r more. When the number-average molecular weight measured by the GPC measurement method is within the above range, the fracture properties and abrasion resistance tend to be excellent. Further, the number-average molecular weight is not particularly limited, but is preferably 75×10 4 or less, more preferably 50×10 4 or less, still more preferably 40×10 4 or less, particularly preferably 35×10 4The following applies: When the above number-average molecular weight is within the above range, the dispersibility of the filler in the vulcanized product tends to be even better, and sufficient fracture properties for practical use are obtained. The above number-average molecular weight may be within a range arbitrarily obtained by combining the above upper and lower limits. The number-average molecular weight measured by the GPC measurement method of the modified conjugated diene polymer and the modified conjugated diene polymer described later is measured in detail by the method described in the examples described later.

[0040] In the modified conjugated diene polymer of this embodiment, the molecular weight distribution (Mw / Mn), which is the ratio of the weight-average molecular weight (Mw) measured by the GPC method to the number-average molecular weight (Mn) measured by the GPC method, is not particularly limited, but from the viewpoint of effectively and reliably achieving the effects of this embodiment, it is preferably 1.5 or more and less than 2.5, more preferably 1.6 or more and 2.1 or less, and even more preferably 1.7 or more and 2.0 or less.

[0041] (Number of branches) The modified conjugated diene polymer in this embodiment has a branched structure, and the number of branches indicates the number of branches in the modified conjugated diene polymer. A higher number of branches tends to improve the moldability of the modified conjugated diene polymer, while a lower number of branches tends to improve fracture characteristics. The number of branches in the modified conjugated diene polymer can be adjusted using branching agents or coupling modifiers described later.

[0042] (Moony viscosity) The Mooney viscosity of the modified conjugated diene polymer of this embodiment, measured at 100°C, is preferably 100 to 150, and more preferably 100 to 130. The Mooney viscosity tends to be higher when the weight-average molecular weight of the modified conjugated diene copolymer is high, and lower when the weight-average molecular weight is low. For example, when the number of branches is 6, the weight-average molecular weight is 57 × 10⁻⁶. 4 This tends to result in a viscosity close to the lower limit of Mooney viscosity, with a weight-average molecular weight of 65 × 10⁻⁶. 4 This tends to result in a viscosity close to the upper limit of the Mooney viscosity. When the number of branches is 4, the weight-average molecular weight is 65 × 10 4This tends to result in a viscosity close to the lower limit of Mooney viscosity, with a weight-average molecular weight of 80 × 10 4 This tends to result in a viscosity close to the upper limit of the Mooney viscosity. When the Mooney viscosity is within the above range, the fluidity of the modified conjugated diene copolymer decreases, resulting in excellent mold retention and further improvements in the fracture characteristics and wear resistance of the vulcanized product. The Mooney viscosity of the modified conjugated diene polymer can be measured by the method described in the examples below.

[0043] (Mooney easing rate) The modified conjugated diene polymer in this embodiment is not particularly limited, but it is preferably 0.40 or more and 0.70 or less, more preferably 0.45 or more and 0.70 or less, and even more preferably 0.50 or more and 0.70 or less, as measured at 100°C. The Mooney relaxation rate serves as an indicator of the molecular weight and branching number of the modified conjugated diene polymer. When the Mooney relaxation rate is within the above range, the moldability of the modified conjugated diene polymer is improved, and the fracture characteristics and wear resistance of the vulcanized product tend to be further improved. The Mooney relaxation rate of the modified conjugated diene polymer can be measured by the method described in the examples below.

[0044] Furthermore, the Mooney relaxation rate is also an indicator of how easily a modified conjugated diene copolymer can become viscous. A high Mooney relaxation rate indicates a higher likelihood of becoming viscous, while a low Mooney relaxation rate indicates a lower likelihood of becoming viscous. Therefore, the Mooney relaxation rate serves as an indicator of mold retention.

[0045] Furthermore, generally speaking, when the Mooney viscosity measured at 100°C is reduced by lowering the molecular weight, reducing the number of branches, or increasing the amount of rubber softener added, the Mooney relaxation rate measured at 100°C tends to increase.

[0046] For example, when comparing modified conjugated diene polymers with the same Mooney viscosity measured at 100°C, the Mooney relaxation rate tends to decrease as the number of branches of the modified conjugated diene polymer increases. Therefore, in this case, the Mooney relaxation rate can be used as an indicator of the number of branches.

[0047] In modified conjugated diene polymers, to achieve a Mooney relaxation rate of 0.40 to 0.70 measured at 100°C, this can be achieved by controlling the number of branches in the polymer, for example, within the range of Mooney viscosity measured at 100°C being 100 to 150. For example, a lower Mooney viscosity tends to result in a higher number of branches; for instance, when the Mooney viscosity is 100, setting the number of branches to 4 tends to bring the Mooney relaxation rate near the upper limit, while setting the number of branches to 5 tends to bring it near the lower limit. Conversely, a higher Mooney viscosity tends to result in a lower number of branches; for example, when the Mooney viscosity is 150, setting the number of branches to 3 tends to bring the Mooney relaxation rate near the upper limit, while setting the number of branches to 4 tends to bring it near the lower limit. The number of branches can be controlled by the number of functional groups in the modifying agent, the amount of modifying agent added, the number of functional groups in the branching agent, the amount of branching agent added, etc.

[0048] (Phase difference index) The modified conjugated diene polymer in this embodiment is not particularly limited, but the tanδ measured at 160°C and a strain of 7% at 0.1 Hz is used as the phase difference index, and the phase difference index is preferably 0.65 to 1.10, and more preferably 0.70 to 1.00. The phase difference index serves as an indicator of the molecular weight, branching number, and glass transition temperature of the modified conjugated diene polymer. When the phase difference index is within the above range, the moldability of the modified conjugated diene polymer is improved, and the fuel efficiency, fracture characteristics, and wear resistance of the vulcanized product tend to be further improved. The phase difference index of the modified conjugated diene polymer can be measured by the method described in the examples below.

[0049] Furthermore, the Mooney relaxation rate measured at 100°C is a function of branching with the Mooney viscosity measured at 100°C, and thus there are similarities between controlling the Mooney relaxation rate and controlling the phase difference index. However, the phase difference index differs from the Mooney relaxation rate in that it depends on the glass transition temperature Tg. The inventors noticed that even polymers designed by controlling the Mooney viscosity and Mooney relaxation rate do not exhibit the expected performance in terms of the balance between fuel efficiency, wear, and tensile strength if the glass transition temperature Tg is shifted. By adding the phase difference index as a control factor, they discovered that the composition after vulcanization exhibits low fuel efficiency even when the glass transition temperature Tg fluctuates within the range of -90°C to -40°C, leading to the present invention.

[0050] Generally, the phase difference index tends to increase when the Mooney viscosity is reduced, the number of branches is reduced, or the glass transition temperature (Tg) is high.

[0051] In modified conjugated diene polymers, to set the phase difference index between 0.65 and 1.10, for example, the weight-average molecular weight Mw and the number of branching molecules of the polymer are controlled within the range of the glass transition temperature Tg being -90°C to -40°C. When the glass transition temperature Tg is low, the Mooney viscosity or the number of branching molecules can be reduced to control it. For example, when the glass transition temperature Tg is -75°C and the Mooney viscosity is 100, setting the number of branching molecules to 3 tends to bring the phase difference index near the upper limit, while setting the number of branching molecules to 4 tends to bring the phase difference index near the lower limit. When the glass transition temperature Tg is -75°C and the Mooney viscosity is 130, setting the number of branching molecules to 2 tends to bring the phase difference index near the upper limit, while setting the number of branching molecules to 3 tends to bring the phase difference index near the lower limit. When the glass transition temperature Tg is high, the Mooney viscosity or the number of branching molecules can be increased to control it. For example, when the glass transition temperature Tg is -60°C and the Mooney viscosity is 100, setting the number of branches to 4 tends to bring the phase difference index near the upper limit, while setting the number of branches to 6 tends to bring the phase difference index near the lower limit. When the glass transition temperature Tg is -60°C and the Mooney viscosity is 130, setting the number of branches to 3 tends to bring the phase difference index near the upper limit, while setting the number of branches to 5 tends to bring the phase difference index near the lower limit. The glass transition temperature Tg can be controlled by the ratio of the amount of bonded aromatic vinyl to the amount of bonded vinyl in the modified conjugated diene polymer, and the number of branches can be controlled by the number of functional groups of the modifier, the amount of modifier added, the number of functional groups of the branching agent, the amount of branching agent added, etc.

[0052] (Manufacturing method) In the method for producing the modified conjugated diene polymer of this embodiment, it is necessary to polymerize the modified conjugated diene polymer while controlling various parameters to satisfy them. As mentioned above, the ratio of aromatic vinyl and the ratio of vinyl bonds in the conjugated diene affect the glass transition temperature Tg and the phase difference index, so conditions are set to satisfy these and polymer chains are formed. Also, the molecular weight and the number of branches affect the Mooney viscosity and Mooney relaxation rate measured at 100°C, so the length of the polymer chain is set to satisfy these and designed to have an appropriate number of branches. The number of branches depends on the introduction of main chain branching and the number of functional groups of the coupling agent, so it is preferable to combine these appropriately. Furthermore, by using branching agents and coupling agents that contain nitrogen and / or silicon, the nitrogen content and / or silicon content of the modified conjugated diene polymer can be increased, so it is necessary to adjust the nitrogen and silicon content to appropriate values ​​along with the number of branches.

[0053] The polymerization process, the process of forming the main chain branch, and the coupling process will be described below. By designing these processes to satisfy various parameters, the modified conjugated diene polymer of this embodiment can be produced.

[0054] (Polymerization initiator) While not particularly limited, organolithium compounds such as organomonolithium compounds can be used as polymerization initiators.

[0055] 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.

[0056] Among these, the organic monolithium compounds are preferably organic lithium compounds having at least one nitrogen atom in the molecule, and more preferably alkyl lithium compounds or dialkylaminolithium compounds having a substituted amino group, from the viewpoint of being able to introduce a nitrogen atom into a conjugated diene polymer.

[0057] A substituted amino group is an amino group that does not have active hydrogen or in which the active hydrogen is protected.

[0058] Examples of alkyllithium compounds having an amino group that does not possess active hydrogen include, but are not limited to, piperidinolithium, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0059] Alkyllithium compounds having an amino group with protected active hydrogen are not particularly limited, but examples include 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0060] Examples of dialkylaminolithium include 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.

[0061] These organomonolithium compounds having substituted amino groups can also be used as solubilized oligomeric organomonolithium compounds by reacting them in small amounts with polymerizable monomers, such as 1,3-butadiene, isoprene, or styrene.

[0062] On the other hand, the polymerization initiator in this embodiment may be produced by reacting a compound represented by chemical formulas (E) and (F) with an organometallic compound, and may be capable of introducing a functional group to one end of the polymer chain formed by polymerization while simultaneously initiating polymerization.

[0063] [ka]

[0064] [ka]

[0065] When a polymerization initiator contains nitrogen atoms that make up an amino group, chain transfer reactions are more likely to occur during anionic polymerization, and the amount of coupling or modifying agent reacting with the active end after polymerization is reduced. As a result, using a polymerization initiator that contains nitrogen atoms that make up an amino group tends to result in a smaller weight-average molecular weight (Mw). Therefore, the weight-average molecular weight (Mw) is 30 × 10 4 The above 40 x 10 4 Above, or 45 x 10 4 In the above-mentioned relatively high molecular weight polymers, when it is desired to set a high nitrogen content, it is preferable to react the nitrogen atoms at the weight-terminating end rather than at the polymerization initiation end. In other words, polymers that are relatively high molecular weight and contain nitrogen atoms at both ends tend to be difficult to produce. Depending on the weight-average molecular weight (Mw) and the structure of the coupling agent and modifier, when nitrogen atoms are present only at the termination end, the nitrogen content of the polymer is generally between 0.1 ppm and 1000 ppm by mass.

[0066] From the viewpoint of ease of industrial availability and ease of control of polymerization reactions, alkyllithium compounds may be used as organic monolithium compounds. When such organic monolithium compounds are used, conjugated diene polymers having an alkyl group at the polymerization initiation end can be obtained.

[0067] The alkyllithium compounds are not particularly limited, but examples include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenithium.

[0068] As alkyllithium compounds, n-butyllithium and sec-butyllithium are preferred from the viewpoint of ease of industrial availability and ease of control of polymerization reactions.

[0069] 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.

[0070] Other organometallic compounds include, but are not limited to, alkaline earth metal compounds, alkali metal compounds other than lithium, and other organometallic compounds.

[0071] Alkaline earth metal compounds are not particularly limited, but examples include organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Compounds of alkaline earth metals as alkoxides, sulfonates, carbonates, and amides are also examples.

[0072] Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium.

[0073] Other organometallic compounds include, for example, organoaluminum compounds.

[0074] (polar compound) The polar compounds are not particularly limited, but examples include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-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 compounds may be used individually or in combination of two or more.

[0075] The amount of polar compound added is not particularly limited, but can be adjusted according to the amount of polymerization active ends, i.e., the amount of polymerization initiator added. Preferably, the amount of polar compound added is 0.010 moles to 1.000 moles per mole of polymerization initiator, and more preferably 0.100 moles to 0.700 moles. Within the above range, the amount of polar compound added may be 0.600 moles or less or 0.500 moles or less per mole of polymerization initiator. Alternatively, it may be 0.150 moles or more or 0.200 moles or more per mole of polymerization initiator. When the amount of polar compound added is below the above upper limit, a conjugated diene compound with a low Tg tends to be obtained. Furthermore, when the amount of polar compound added is above the above lower limit, deactivation of polymerization active ends is suppressed, and the coupling rate in the coupling step described later tends to improve. The amount of polar compound added may be within a range that is an arbitrary combination of the above upper and lower limits.

[0076] (Main chain branching structure) The modified conjugated diene polymer of this embodiment may contain a main chain branched structure. The main chain branched structure has two or more branching points at the branching point in the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group, preferably three or more branching points, and more preferably four or more branching points.

[0077] Furthermore, it is preferable that the branching points that form the main chain branching structure have at least two polymer chains, more preferably three or more polymer chains that are not part of the main chain, and even more preferably four or more polymer chains that are not part of the main chain.

[0078] In particular, in main-chain branched structures consisting of vinyl monomers containing alkoxysilyl or halosilyl groups, 29 When the signal is detected by Si-NMR, peaks originating from the main chain branching structure are detected in the range of -45 ppm to -65 ppm, and more specifically in the range of -50 ppm to -60 ppm.

[0079] (Branching agent) In the modified conjugated diene polymer of this embodiment, it is preferable to use a branching agent represented by the following formula (1) or formula (2) as the branching agent when constructing the main chain branched structure.

[0080] [ka] (In formula (1), R 1 This represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. R 2 ~R 3 Each of these independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. When multiple Rs exist 1 ~R 3 These are independent of each other and may be the same or different. X 1 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m+n+l) represents 3.

[0081] [ka] (In formula (2), R 2 ~R 5 Each of these independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. When multiple Rs exist 2 ~R 5 These are independent of each other and may be the same or different. X 2 ~X 3 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m+n+l) represents 3. a represents an integer between 0 and 2, b represents an integer between 0 and 3, and c represents an integer between 0 and 3. (a + b + c) equals 3.

[0082] In this embodiment, the branching agent used to construct the main chain branched structure of the modified conjugated diene polymer is a compound represented by formula (1), from the viewpoint of polymerization continuity and improvement of the number of branches, and R 1 A compound in which the atom is a hydrogen atom and m=0 is preferred.

[0083] Furthermore, in this embodiment, the branching agent used to construct the main chain branched structure of the modified conjugated diene polymer is preferably a compound represented by formula (2) where m=0 and b=0, from the viewpoint of improving the number of branches.

[0084] Furthermore, in this embodiment, the branching agent used when constructing the main chain branched structure of the modified conjugated diene polymer is a compound represented by formula (1), from the viewpoint of polymerization continuity and improvement of the number of branches, and R 1A compound in which the atom is a hydrogen atom, m=0, l=0, and n=3 is more preferred.

[0085] Furthermore, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is preferably a compound represented by formula (2) above, where m=0, l=0, n=3, and a=0, b=0, c=3, from the viewpoint of improving the number of branches.

[0086] The branching agent represented by formula (1) is not limited to the following, but for example, Trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, Tripropoxy(4-vinylphenyl)silane, Tributoxy(4-vinylphenyl)silane, Triisopropoxy(4-vinylphenyl)silane, Trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, Tripropoxy(3-vinylphenyl)silane, Tributoxy(3-vinylphenyl)silane, Triisopropoxy(3-vinylphenyl)silane, Trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, Tripropoxy(2-vinylphenyl)silane, Tributoxy(2-vinylphenyl)silane, Triisopropoxy(2-vinylphenyl)silane,

[0087] Dimethoxymethyl(4-vinylphenyl)silane, diethoxymethyl(4-vinylphenyl)silane, dipropoxymethyl(4-vinylphenyl)silane, dibutoxymethyl(4-vinylphenyl)silane, diisopropoxymethyl(4-vinylphenyl)silane, Dimethoxymethyl(3-vinylphenyl)silane, diethoxymethyl(3-vinylphenyl)silane, dipropoxymethyl(3-vinylphenyl)silane, dibutoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, Dimethoxymethyl(2-vinylphenyl)silane, diethoxymethyl(2-vinylphenyl)silane, dipropoxymethyl(2-vinylphenyl)silane, dibutoxymethyl(2-vinylphenyl)silane, diisopropoxymethyl(2-vinylphenyl)silane, Dimethylmethoxy(4-vinylphenyl)silane, dimethylethoxy(4-vinylphenyl)silane, dimethylpropoxy(4-vinylphenyl)silane, dimethylbutoxy(4-vinylphenyl)silane, dimethylisopropoxy(4-vinylphenyl)silane, Dimethylmethoxy(3-vinylphenyl)silane, dimethylethoxy(3-vinylphenyl)silane, dimethylpropoxy(3-vinylphenyl)silane, dimethylbutoxy(3-vinylphenyl)silane, dimethylisopropoxy(3-vinylphenyl)silane, Dimethylmethoxy(2-vinylphenyl)silane, dimethylethoxy(2-vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, dimethylisopropoxy(2-vinylphenyl)silane, Trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, tripropoxy(4-isopropenylphenyl)silane, tributoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl)silane, triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tributoxy(3-isopropenyl(3-isopropenyl Phenyl)silane, trimethoxy(2-isopropenylphenyl)silane, triethoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tripbutoxy(2-isopropenylphenyl)silane, triisopropoxy(2-isopropenylphenyl)silane, dimethoxymethyl(4-isopropenylphenyl)silane, diethoxymethyl(4-isopropenylphenyl)silane, dipropoxymethyl(4-isopropenylphenyl)silane, dibutoxymethyl(4-isopropenylphenyl)silane, di Sopropoxymethyl(4-isopropenylphenyl)silane, dimethoxymethyl(3-isopropenylphenyl)silane, diethoxymethyl(3-isopropenylphenyl)silane, dipropoxymethyl(3-isopropenylphenyl)silane, dibutoxymethyl(3-isopropenylphenyl)silane, diisopropoxymethyl(3-isopropenylphenyl)silane, dimethoxymethyl(2-isopropenylphenyl)silane, diethoxymethyl(2-isopropenylphenyl)silane, dipropoxymethyl(2-isopropenylphenyl)silane, Dibutoxymethyl(2-isopropenylphenyl)silane, diisopropoxymethyl(2-isopropenylphenyl)silane, dimethylmethoxy(4-isopropenylphenyl)silane, dimethylethoxy(4-isopropenylphenyl)silane, dimethylpropoxy(4-isopropenylphenyl)silane, dimethylbutoxy(4-isopropenylphenyl)silane, dimethylisopropoxy(4-isopropenylphenyl)silane, dimethylmethoxy(3-isopropenylphenyl)silane, dimethylethoxy(3-isopropenylphenyl)silane,Dimethylpropoxy(3-isopropenylphenyl)silane, dimethylbutoxy(3-isopropenylphenyl)silane, dimethylisopropoxy(3-isopropenylphenyl)silane, dimethylmethoxy(2-isopropenylphenyl)silane, dimethylethoxy(2-isopropenylphenyl)silane, dimethylpropoxy(2-isopropenylphenyl)silane, dimethylbutoxy(2-isopropenylphenyl)silane, dimethylisopropoxy(2-isopropenylphenyl)silane,

[0088] Trichloro(4-vinylphenyl)silane, Trichloro(3-vinylphenyl)silane, Trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane, Examples include dichloromethyl(4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl(2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo(3-vinylphenyl)silane, and dimethylbromo(2-vinylphenyl)silane.

[0089] Among these, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, and trichloro(4-vinylphenyl)silane are preferred, with trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, and tributoxy(4-vinylphenyl)silane and triisopropoxy(4-vinylphenyl)silane being more preferred.

[0090] The branching agent represented by formula (2) above is not limited to the following, but for example, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-trippropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-triethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(3-triisopropoxysilylphenyl)ethylene, 1,1-bis(2-trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(2-tripentoxysilylphenyl)ethylene, 1,1-bis(2-triisopropoxysilylphenyl)ethylene, Examples include 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dimethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylethoxysilyl)phenyl)ethylene, and 1,1-bis(4-(dipropylethoxysilyl)phenyl)ethylene.

[0091] Among these, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-trippropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene are preferred, and 1,1-bis(4-trimethoxysilylphenyl)ethylene is more preferred.

[0092] (Modified group containing nitrogen and silicon atoms) The modified conjugated diene polymer of this embodiment has a modifying group. A "modifying group" refers to a functional group that has affinity or bonding reactivity with the filler and contains a nitrogen atom. By having such a modifying group, the modified conjugated diene polymer's interaction with the filler is further improved, and when a modified conjugated diene polymer composition containing the modified conjugated diene polymer and the filler is formed, the mechanical strength of the composition is further improved. From a similar viewpoint, the modified conjugated diene polymer of this embodiment has silicon atoms and nitrogen atoms. It is not necessary for a single modifying group or modifying agent to contain both nitrogen atoms and silicon atoms; a modifying group containing only one of them or a modifying agent having a modifying group may be combined so that the polymer contains both nitrogen atoms and silicon atoms in predetermined amounts.

[0093] The modified conjugated diene polymer of this embodiment can be modified by reacting a copolymer of a conjugated diene compound and an aromatic vinyl compound with a modifying agent. It is preferable that the modified conjugated diene polymer is modified with a coupling modifying agent described later.

[0094] (Nitrogen content and silicon content) In this embodiment, the modified conjugated diene polymer preferably contains 50 ppm or more of nitrogen atoms and silicon atoms, each on a mass basis relative to the total amount of the modified conjugated diene polymer. More preferably, the nitrogen and silicon atom content is 60 ppm or more, and even more preferably 70 ppm or more. The silicon atom content is particularly preferably 100 ppm or more. There is no particular upper limit, but approximately 1000 ppm is preferred. When within this range, the rubber composition containing the modified conjugated diene polymer exhibits excellent abrasion resistance, fracture characteristics, and low hysteresis loss. The nitrogen atom content may originate from the modifying group, and the silicon atom content may originate from the modifying group and the branching agent described later. The nitrogen and silicon content in the modified conjugated diene polymer can be measured by the method described in the examples below.

[0095] (Degeneration rate) In this specification, "modification rate" refers to the percentage by mass of a modified conjugated diene polymer component having a specific functional group in its polymer molecule that has affinity or binding reactivity to a filler, relative to the total amount of the conjugated diene polymer mixture, when a mixture of a modified conjugated diene polymer and an unmodified conjugated diene polymer is obtained by modifying a conjugated diene polymer with a modifying agent. Therefore, if the specific functional group contains a nitrogen atom, it refers to the mass ratio of the modified conjugated diene polymer containing the nitrogen atom to the total amount of the conjugated diene polymer mixture.

[0096] In this specification, "modified conjugated diene polymer" means a modified conjugated diene copolymer, and a mixture of a modified conjugated diene copolymer and an unmodified conjugated diene copolymer. Furthermore, "conjugated diene polymer" means an unmodified conjugated diene polymer.

[0097] For example, in a conjugated diene polymer that includes a modified conjugated diene polymer that has been modified by reacting a nitrogen atom-containing modifying agent with the terminal end of the conjugated diene polymer, the modification rate is the mass ratio of the modified conjugated diene polymer having nitrogen atom-containing functional groups due to the nitrogen atom-containing modifying agent to the total amount of the modified conjugated diene polymer.

[0098] The modified conjugated diene polymer of this embodiment contains at least a portion of nitrogen atoms and silicon atoms. Such a modified conjugated diene polymer exhibits even greater abrasion resistance, fracture strength, and low hysteresis loss when used as a vulcanized product.

[0099] From the viewpoint of improving processability during vulcanization, the modification rate of the modified conjugated diene polymer in this embodiment is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, particularly preferably 75% by mass or more, and most preferably 80% by mass or more, based on the total amount of the modified conjugated diene polymer. The upper limit of the above modification rate is not particularly limited, but may be, for example, 100% by mass, 98% by mass, 95% by mass, or 90% by mass. When comparing modified conjugated diene polymers with the same glass transition temperature, a higher modification rate tends to result in better low hysteresis loss.

[0100] In this embodiment, the denaturation rate can be measured 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).

[0101] More specifically, the denaturation rate can be obtained by calculating the amount adsorbed onto the silica column from the difference between the chromatogram obtained by measuring the sample solution containing the sample and low molecular weight internal standard polystyrene on a polystyrene gel column and the chromatogram obtained by measuring the same sample solution on a silica column. More specifically, the denaturation rate can be measured by the method described in the examples.

[0102] In the modified conjugated diene polymer of this embodiment, the nitrogen content and / or silicon content can be controlled by adjusting the amount of modifying agent added and the reaction method between the conjugated diene compound and the modifying agent.

[0103] For example, one can combine a polymerization method using an organolithium compound having at least one nitrogen atom in the molecule as a polymerization initiator, a copolymerization method using a monomer having at least one nitrogen atom in the molecule, and a structural formula modifier as described later.

[0104] (Coupling) In this embodiment, the modified conjugated diene polymer is preferably obtained by performing a coupling reaction on the active end of the conjugated diene polymer using a trifunctional or more reactive compound (hereinafter also referred to as a "coupling modifier"), and the modified conjugated diene polymer is preferably obtained by this reaction.

[0105] In the coupling step, a coupling reaction is carried out with one end of the active end of the conjugated diene polymer using a coupling modifier having a nitrogen atom and / or a silicon atom, thereby obtaining a modified conjugated diene polymer. More specifically, this is described in the method for producing the modified conjugated diene polymer described below.

[0106] (Coupling denaturant) From the viewpoint of effectively and reliably achieving the effects of this embodiment, the modified conjugated diene polymer of this embodiment preferably has nitrogen atoms and silicon atoms. Among these, it is more preferable that it includes a structure derived from a compound represented by any of the following formulas (A) to (D). The modified conjugated diene polymer is even more preferably modified using a compound represented by any of the following formulas (A) to (D) as a coupling modifier. Examples of compounds represented by any of the following formulas (A) to (D) will be described later. These coupling modifiers may be used individually or in combination of two or more.

[0107] [ka] (In formula (A), R 9 , R 10 R is a hydrocarbon group having 1 to 12 carbon atoms, which may have unsaturated bonds and may be the same or different. 11 R is a hydrocarbon group having 1 to 20 carbon atoms. 7 , R 8 R is an aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may have unsaturated bonds and may be the same or different. 6 (where is a hydrocarbon group having 1 to 20 carbon atoms, containing Si, O, or N, and may be substituted with an organic group that does not have active hydrogen, and may contain unsaturated bonds. d is an integer from 1 to 3.)

[0108] [ka] (In formula (B), A represents a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and not having active hydrogen, R 12 , R 13 , and R 14 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R 15 , R 16 , R 17 , R 18 , and R 20Each independently represents an alkyl group having 1 to 20 carbon atoms, and R 19 , and R 21 Each independently represents an alkylene group having 1 to 20 carbon atoms, R 22 Each of the following independently represents an alkyl group having 1 to 20 carbon atoms, or a trialkylsilyl group; each of the following independently represents an integer from 1 to 3; each of the following independently represents 1 or 2; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; and the sum of i, j, and k is an integer from 4 to 10.

[0109] [ka] (In formula (C), R 23 , R 24 , R 25 , R 26 , R 27 , and R 28 Each independently represents an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R 29 , R 30 , and R 31 Each of the following independently represents an alkylene group having 1 to 20 carbon atoms, and each of s, t, and u independently represents an integer from 1 to 3, with the sum of s, t, and u being an integer of 4 or greater.

[0110] [ka] (In formula (D), B 1 and B 2 Each of these is independently a divalent hydrocarbon group having 1 to 20 carbon atoms, either containing or not containing an oxygen atom, and R 32 ~R 35 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L 1 ~L 4 Each of these is independently a divalent, trivalent, or tetravalent alkylsilyl group substituted with an alkyl group having 1 to 10 carbon atoms, or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or L 1 and L 2 And, L 3 and L 4may be connected to each other to form a ring having 1 to 5 carbon atoms, and L 1 and L 2 and L 3 and L 4 When they are connected to each other to form a ring, the formed ring may contain 1 to 3 heteroatoms selected from the group consisting of N, O, and S.)

[0111] As a specific example, in formula (D), B 1 and B<所 2 are each independently an alkylene group having 1 to 10 carbon atoms, and R 32 ~R 35 are each independently an alkyl group having 1 to 10 carbon atoms, and L 1 ~L 4 are each independently a tetravalent alkylsilyl group substituted with an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or L 1 and L 2 and L 3 and L 4 may be connected to each other to form a ring having 1 to 3 carbon atoms, and L 1 and L 2 and L 3 and L 4 When they are connected to each other to form a ring, the formed ring may contain 1 to 3 heteroatoms selected from the group consisting of N, O and S.)

[0112] (Method for producing modified conjugated diene polymer) The above-mentioned modified conjugated diene polymer can be produced by any method as long as it is a method for obtaining a polymer having the above-mentioned configuration. Preferred examples will be detailed below. By using the method for producing a modified conjugated diene polymer of the present embodiment, the above-mentioned modified conjugated diene polymer can be obtained reliably and simply.)

[0113] It should be noted that there seems to be a misspelling in "<所 2 ", which should probably be corrected to the correct tag before accurate translation.In the method for producing a modified conjugated diene polymer of this embodiment, a coupling step is performed in which an organolithium compound is used as a polymerization initiator to polymerize at least a conjugated diene compound and an aromatic vinyl compound while reacting with a coupling modifier, thereby obtaining a modified conjugated diene polymer.

[0114] At least the polymerization reaction of the conjugated diene compound and the aromatic vinyl compound is preferably carried out by a growth reaction via living anionic polymerization. This allows for the production of a conjugated diene polymer having active ends. As a result, when a branching agent is added, the conjugated diene polymer and the branching agent react efficiently. Furthermore, even when the production method of this embodiment includes a coupling step described later, a highly efficient reaction tends to occur.

[0115] Polymerization reaction modes are not limited to the following, but examples include batch (hereinafter also referred to as "batch") and continuous polymerization reaction modes.

[0116] In a continuous reactor, one or more connected reactors can be used. Examples of continuous reactors include tank-type and tubular-type reactors equipped with stirrers. Preferably, monomers, an inert solvent (described later), and a polymerization initiator (described later) are continuously fed into the reactor, a polymer solution containing the polymer is obtained within the reactor, and the polymer solution is continuously discharged.

[0117] As a batch reactor, for example, a tank-type reactor with a stirrer is used. In the batch reactor, preferably, monomers, an inert solvent (described later), and a polymerization initiator (described later) are 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.

[0118] In the manufacturing method of this embodiment, from the viewpoint of obtaining a conjugated diene polymer having active ends in a high proportion, it is preferable to carry out the polymerization reaction by a continuous polymerization reaction mode that allows the polymer to be continuously discharged and used for the next reaction in a short time.

[0119] The amount of polymerization initiator added is preferably determined by the molecular weight of the target modified conjugated diene polymer. The number-average molecular weight (Mn) and / or weight-average molecular weight (Mw) can be controlled by the ratio of the monomer added to the amount of polymerization initiator added. Specifically, decreasing the proportion of polymerization initiator added tends to increase the molecular weight, while increasing the proportion of polymerization initiator added tends to decrease the molecular weight.

[0120] From the viewpoint of reliably and easily obtaining the modified conjugated diene polymer of this embodiment, it is preferable to carry out the polymerization reaction in an inert solvent. Such an inert solvent is not particularly limited, but examples include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not particularly limited, but examples include aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and hydrocarbons consisting of mixtures thereof.

[0121] From the viewpoint of obtaining a modified conjugated diene polymer in which a conjugated diene compound and an aromatic vinyl compound are randomly polymerized in a layer, the following method, such as that described in Japanese Patent Publication No. 59-140211, may be used. Specifically, a method may be used in which the polymerization reaction is started using the entire amount of the aromatic vinyl compound and a portion of the conjugated diene compound, and then the remaining conjugated diene compound is intermittently added during the polymerization reaction.

[0122] The manufacturing method of this embodiment may include a step to remove impurities. In particular, if the monomer, polymerization initiator, and / or inert solvent described above contain allenes and acetylenes as impurities, it is preferable that the manufacturing method of this embodiment includes a step to remove impurities before the polymerization branching step. By including a step to remove impurities, a conjugated diene polymer with a high concentration of active ends tends to be obtained, and a modified conjugated diene polymer with a high modification rate in the coupling step described later and a high nitrogen and / or silicon content tends to be obtained. The step to remove such impurities is not particularly limited, but for example, it may include a step of treatment with an organometallic compound. The organometallic compound is not particularly limited, but for example, it may include an organolithium compound, and the organolithium compound is not particularly limited, but for example, it may include n-butyllithium.

[0123] (Polymerization and branching process) The method for producing the modified conjugated diene polymer of this embodiment may include a polymerization branching step. This polymerization branching step is a step in which a conjugated diene polymer having a branched structure is obtained by adding a branching agent while polymerizing at least a conjugated diene compound and an aromatic vinyl compound, for example, using an organolithium compound as a polymerization initiator. Therefore, in the polymerization branching step, the polymerization reaction of at least the conjugated diene compound and the aromatic vinyl compound is the main reaction before the addition of the branching agent, and the branching reaction starts after the addition of the branching agent.

[0124] In the polymerization branching process, the addition of a branching agent initiates the branching reaction in the conjugated diene polymer. After the addition of the branching agent, two reactions occur in the reaction system: the polymerization reaction in which the conjugated diene polymer grows, and the branching reaction in which the conjugated diene polymer branches. Therefore, by controlling the type and amount of branching agent added, as well as the timing of its addition, it is possible to control the weight-average molecular weight (Mw), number-average molecular weight (Mn), molecular weight distribution (Mw / Mn), the number of branches, the number of branching points, and the number of branches at each branching point of the conjugated diene polymer obtained in the polymerization branching process.

[0125] In the overlapping branching step, the timing of adding the branching agent is not particularly limited and can be appropriately selected according to the use of the modified conjugated diene polymer to be produced and the like. From the viewpoint of improving the nitrogen content and / or silicon content in the coupling step of the obtained modified conjugated diene polymer, the timing of adding the branching agent is preferably the timing when the raw material conversion rate is 20% or more after adding the polymerization initiator, more preferably 40% or more, still more preferably 50% or more, even more preferably 65% or more, and particularly preferably 75% or more. That is, the timing of adding the branching agent is preferably the timing when the polymerization reaction is sufficiently stable.

[0126] The branching agent is not particularly limited. For example, a compound represented by the following formula (1) or formula (2) can be used.

[0127]

Chemical formula

[0128]

Chemical formula

[0129] Among these, the branching agent is a compound represented by formula (1) above, from the viewpoint of suppressing inhibition of polymerization reactions and improving the number of branches, and R 1 A compound in which is a hydrogen atom and m is 0 is preferred.

[0130] Alternatively, from the viewpoint of improving the number of branches, the branching agent is preferably a compound represented by formula (2) above, in which m is 0 and b is 0.

[0131] Alternatively, the branching agent is a compound represented by formula (1) above, from the viewpoint of the continuity of polymerization and the improvement of the number of branches, R 1 A compound in which is a hydrogen atom, m is 0, l is 0, and n is 3 is more preferred.

[0132] Alternatively, from the viewpoint of improving the number of branches, the branching agent is preferably a compound represented by formula (2) above, wherein m is 0, l is 0, n is 3, a is 0, b is 0, and c is 3.

[0133] The compound represented by formula (1) is not limited to the following, but examples include trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tripbutoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane (2-vinylphenyl)silane, trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, tripropoxy(2-vinylphenyl)silane, tripbutoxy(2-vinylphenyl)silane, triisopropoxy(2-vinylphenyl)silane, dimethoxymethyl(4-vinylphenyl)silane, diethoxymethyl(4-vinylphenyl)silane, dipropoxymethyl(4-vinylphenyl)silane, dibutoxymethyl(4-vinylphenyl)silane, diisopropoxymethyl(4-vinylphenyl)silane, dimethoxymethyl (3-vinylphenyl)silane, diethoxymethyl(3-vinylphenyl)silane, dipropoxymethyl(3-vinylphenyl)silane, dibutoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, dimethoxymethyl(2-vinylphenyl)silane, diethoxymethyl(2-vinylphenyl)silane, dipropoxymethyl(2-vinylphenyl)silane, dibutoxymethyl(2-vinylphenyl)silane, diisopropoxymethyl(2-vinylphenyl)silane, dimethylmethoxy(4-vinylphenyl phenyl)silane, dimethylethoxy(4-vinylphenyl)silane, dimethylpropoxy(4-vinylphenyl)silane, dimethylbutoxy(4-vinylphenyl)silane, dimethylisopropoxy(4-vinylphenyl)silane, dimethylmethoxy(3-vinylphenyl)silane, dimethylethoxy(3-vinylphenyl)silane, dimethylpropoxy(3-vinylphenyl)silane, dimethylbutoxy(3-vinylphenyl)silane, dimethylisopropoxy(3-vinylphenyl)silane, dimethylmethoxy(2-vinylphenyl)silane,Dimethylethoxy(2-vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, dimethylisopropoxy(2-vinylphenyl)silane, trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, tripropoxy(4-isopropenylphenyl)silane, tripbutoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl) Silane, triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tributoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl)silane, triethoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tributoxy(2-isopropenylphenyl)silane, triisopropoxy(2-isopropenylphenyl)silane, dimethoxymethyl (4-isopropenylphenyl)silane, diethoxymethyl(4-isopropenylphenyl)silane, dipropoxymethyl(4-isopropenylphenyl)silane, dibutoxymethyl(4-isopropenylphenyl)silane, diisopropoxymethyl(4-isopropenylphenyl)silane, dimethoxymethyl(3-isopropenylphenyl)silane, diethoxymethyl(3-isopropenylphenyl)silane, dipropoxymethyl(3-isopropenylphenyl)silane, dibutoxymethyl(3-isopropenylphenyl)silane, diisoprop Poxymethyl(3-isopropenylphenyl)silane, dimethoxymethyl(2-isopropenylphenyl)silane, diethoxymethyl(2-isopropenylphenyl)silane, dipropoxymethyl(2-isopropenylphenyl)silane, dibutoxymethyl(2-isopropenylphenyl)silane, diisopropoxymethyl(2-isopropenylphenyl)silane, dimethylmethoxy(4-isopropenylphenyl)silane, dimethylethoxy(4-isopropenylphenyl)silane, dimethylpropoxy(4-isopropenylphenyl)silane,Dimethylbutoxy(4-isopropenylphenyl)silane, dimethylisopropoxy(4-isopropenylphenyl)silane, dimethylmethoxy(3-isopropenylphenyl)silane, dimethylethoxy(3-isopropenylphenyl)silane, dimethylpropoxy(3-isopropenylphenyl)silane, dimethylbutoxy(3-isopropenylphenyl)silane, dimethylisopropoxy(3-isopropenylphenyl)silane, dimethylmethoxy(2-isopropenylphenyl)silane, dimethylethoxy(2-isopropenylphenyl)silane, dimethylpropoxy(2-isopropenylphenyl)silane, dimethylbutoxy(2-isopropenylphenyl)silane, dimethylisopropoxy(2-isopropenylphenyl)silane, trichloro(4-vinylphenyl)silane, trichloro(3- Examples include vinylphenyl)silane, trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane, dichloromethyl(4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl(2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo(3-vinylphenyl)silane, and dimethylbromo(2-vinylphenyl)silane.

[0134] Among these, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, and trichloro(4-vinylphenyl)silane are preferred, with trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, and tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane being more preferred.

[0135] The compound represented by formula (2) is not limited to the following, but includes, for example, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-trippropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(2- Examples include trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(2-tripentoxysilylphenyl)ethylene, 1,1-bis(2-triisopropoxysilylphenyl)ethylene, 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dimethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylethoxysilyl)phenyl)ethylene, and 1,1-bis(4-(dipropylethoxysilyl)phenyl)ethylene.

[0136] Among these, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene are preferred, with 1,1-bis(4-trimethoxysilylphenyl)ethylene being more preferred.

[0137] The amount of branching agent added can be appropriately selected depending on the intended use of the modified conjugated diene polymer being manufactured, and is not particularly limited, but is preferably 0.020 moles or more and 0.50 moles or less per mole of polymerization initiator, more preferably 0.030 moles or more and 0.40 moles or less, and even more preferably 0.040 moles or more and 0.25 moles or less. Within the above range, the amount of branching agent added may be 0.050 moles or more per mole of polymerization initiator. Alternatively, it may be 0.20 moles or less or 0.18 moles or less per mole of polymerization initiator. The amount of branching agent added may be within a range that is an arbitrary combination of the above upper and lower limits.

[0138] In the polymerization branching process, the reaction temperature may be changed after adding the branching agent, or it may not be changed.

[0139] In the polymerization branching step, after adding the branching agent, monomers of the conjugated diene polymer may be added further, and then the branching agent may be added again, and the addition of branching agents and monomers may be repeated.

[0140] The monomer to be added is not particularly limited, but from the viewpoint of improving the nitrogen content and / or silicon content in the coupling step, it is preferable to add the same monomer that was initially added as a monomer in the polymerization branching step. The amount of monomer to be added may be 1.0% or more, 5.0% or more, 10% or more, 15% or more, or 20% or more of the total amount used as monomers in the conjugated diene polymer. Furthermore, the amount of monomer to be added may be 50% or less, 40% or less, or 35% or less.

[0141] When the amount of added monomer falls within the above range, the molecular weight between the branching point created by the addition of the branching agent and the branching point created by the addition of the coupling modifier becomes longer, which tends to result in a molecular structure with high linearity. By giving the resulting conjugated diene polymer such a structure, the entanglement of the molecular chains of the conjugated diene polymer increases when it is vulcanized, which tends to result in a vulcanized product with excellent wear resistance, handling stability, and fracture strength.

[0142] (Coupling process) The method for producing the modified conjugated diene polymer of this embodiment preferably includes a coupling step in which the conjugated diene polymer having a branched structure obtained by the polymerization branching step described above is reacted with a coupling modifier to obtain a modified conjugated diene polymer. Having such a coupling step allows the conjugated diene polymer to be modified with a specific functional group that has affinity or bonding reactivity to the filler. Furthermore, multiple conjugated diene polymers can be coupled. Therefore, a production method having such a coupling step makes it possible to obtain the conjugated diene polymer of this embodiment described above more reliably and simply.

[0143] Such coupling modifiers are not particularly limited as long as they are reactive compounds having specific functional groups that have affinity or bonding reactivity to the filler and that have two or more functional groups capable of reacting with the active ends of the conjugated diene polymer. Examples of such coupling modifiers include coupling modifiers having groups containing nitrogen atoms and / or silicon atoms. From the viewpoint of effectively and reliably achieving the effects of this embodiment, the coupling modifier preferably has three or more, more preferably four or more, functional groups capable of reacting with the active ends of the conjugated diene polymer. One or more coupling modifiers may be used.

[0144] The coupling modifier having a group containing a silicon atom is not particularly limited, but examples include alkoxysilane compounds containing a nitrogen-containing group.

[0145] The nitrogen atom-containing alkoxysilane compounds are not particularly limited, but examples include 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, and 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimid 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 3-dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, bis(3-dimethoxymethylsilylpropyl)-N-methylamine, bis(3-trimethoxysilylpropyl)-N-methylamine, bis(3-triethoxysilylpropyl)methylamine, ris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N',N'-tetra(3-trimethoxysilylpropyl)ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1- Aza-2-silacyclohexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, and 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,One example is 6-dioxa-2-silacyclooctane.

[0146] Particularly preferred nitrogen atom-containing alkoxysilane compounds are not limited to, but include, for example, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine ("N,N,N',N'-tetrakis(3-trimeth Also known as "xysilylpropyl)-1,3-propanediamine," tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl] [3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, pentaquis(3-trimethoxy Sisilylpropyl)-diethylenetriamine, Tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, Tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, Tris[3-(2,[2-Dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, 3-Tris[2-(2,2-Dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane, 1-[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-3,4,5 -Tris(3-trimethoxysilylpropyl)-cyclohexane, 1-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-3,4,5-Tris(3-trimethoxysilylpropyl)-cyclohexane, 3,4,5-Tris(3-trimethoxysilylpropyl)-cyclohexyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ether, (3-trimethoxysilylpropyl Tris(3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl) phosphate, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl) phosphate, tris(3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl) phosphate, N-(1,3-dimeth Rubylidene)-3-(triethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-(trimethoxysilyl)-1-propanamine, N-benzylidene-3-(triethoxysilyl)propan-1-amine, N-benzylidene-3-(trimethoxysilyl)propan-1-amine, 1,1-(1,4-phenylene)bis(N-(3(triethoxysilyl)propyl)methaneamine), 1,1-(1,4-Phenylene)bis(N-(3(trimethoxysilyl)propyl)methaneamine), 2-Methoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, and 2-Methoxy-2-methyl-1-(4-methoxybenzylideneaminoethyl)-1-aza-2-silacyclopentane, 1-Methyl-4-[3-(trimethoxysilyl)propyl]piperazine, 1-Methyl-4-[3-(triethoxysilyl)propyl]piperazine, 1-Methyl-4-[3-(methyldimethoxysilyl)propyl]piperazine, 3,3'-( 1,1,3,3-Tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-Tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-Tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-Tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine), 3,3'-(1,1,3,3-Tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine), 3,3'-(1,1,3,3-Tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine) Toxydisiloxane-1,3-diyl)bis(N,N-dipropylpropane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dipropylpropane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane -1,3-diyl)bis(N,N-dipropylpropane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-diethylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N- Examples include dimethylmethane-1-amine, 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 1,3-bis(3-(1H-imidazole-1-yl)propyl)1,1,3,3-tetramethoxydisiloxane, 1,3-bis(3-(1H-imidazole-1-yl)propyl)1,1,3,3-tetraethoxydisiloxane, and 1,3-bis(3-(1H-imidazole-1-yl)propyl)1,1,3,3-tetrapropoxydisiloxane.

[0147] Among coupling modifiers having a group containing a nitrogen atom, protected amine compounds in which active hydrogen is substituted with a protecting group include alkoxysilanes and compounds having a protected amine in their molecule. Such compounds are not particularly limited, but include, for example, N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexapropyl Dropyrimidinyl)propyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(3-dimethoxysilylbutyl)-1-aza-2-silacyclohexane, Toxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl )-1-propanamine, N-ethylidene-3-(trimethoxysilyl)-1-propanamine, N-ethylidene-3-methyl(dimethoxysilyl)-1-propanamine, N-ethylidene-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-methyl(dimethoxysilyl) Silyl)-1-propanamine, N-(1-methylpropyridene)-3-methyl(diethoxysilyl)-1-propanamine, N-benzylidene-3-methyl(dimethoxysilyl)propan-1-amine, N-benzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(triethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(trimethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3- Methyl(dimethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-naphthylidene-3-(triethoxysilyl)propan-1-amine, N-naphthylidene-3-(trimethoxysilyl)propan-1-amine, N-naphthylidene-3-methyl(dimethoxysilyl)propan-1-amine, 1,1-(1,4-phenylene)bis(N-(3methyl(dimethoxysilyl)propyl)methaneamine), 1,1-(1,Examples include 4-phenylene)bis(N-(3-methyl(diethoxysilyl)propyl)methaneamine), 2-ethoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, and 2-methoxy-2-methyl-1-(methylisobutylideneaminoethyl)-1-aza-2-silacyclopentane, 1-trimethylsilyl-4-[3-(trimethoxysilyl)propyl]piperazine, and 1-trimethylsilyl-4-[3-(triethoxysilyl)propyl]piperazine.

[0148] In the coupling process, it is preferable to use a coupling modifier represented by any of the following formulas (A) to (D). These can be used individually or in any combination of the following formulas (A) to (D).

[0149] [ka] (In formula (A), R 9 , R 10 R is a hydrocarbon group having 1 to 12 carbon atoms, which may have unsaturated bonds and may be the same or different. 11 R is a hydrocarbon group having 1 to 20 carbon atoms. 7 , R 8 R is an aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may have unsaturated bonds and may be the same or different. 6 (where is a hydrocarbon group having 1 to 20 carbon atoms, containing Si, O, or N, and may be substituted with an organic group that does not have active hydrogen, and may contain unsaturated bonds. d is an integer from 1 to 3.)

[0150] [ka] (In formula (B), A represents a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and not having active hydrogen, R 12 , R 13 , and R14 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R 15 , R 16 , R 17 , R 18 , and R 20 Each independently represents an alkyl group having 1 to 20 carbon atoms, and R 19 , and R 21 Each independently represents an alkylene group having 1 to 20 carbon atoms, R 22 Each of the following independently represents an alkyl group having 1 to 20 carbon atoms, or a trialkylsilyl group; each of the following independently represents an integer from 1 to 3; each of the following independently represents 1 or 2; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; each of the following independently represents an integer from 0 to 6; and the sum of i, j, and k is an integer from 4 to 10.

[0151] [ka] (In formula (C), R 23 , R 24 , R 25 , R 26 , R 27 , and R 28 Each independently represents an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R 29 , R 30 , and R 31 Each of the following independently represents an alkylene group having 1 to 20 carbon atoms, and each of s, t, and u independently represents an integer from 1 to 3, with the sum of s, t, and u being an integer of 4 or greater.

[0152] [ka] (In formula (D), B 1 and B 2 Each of these is independently a divalent hydrocarbon group having 1 to 20 carbon atoms, either containing or not containing an oxygen atom, and R 32 ~R 35 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L 1 ~L 4Each of these is independently a divalent, trivalent, or tetravalent alkylsilyl group substituted with an alkyl group having 1 to 10 carbon atoms, or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or L 1 and L 2 And, L 3 and L 4 These may be linked together to form a ring with 1 to 5 carbon atoms, L 1 and L 2 And, L 3 and L 4 When these elements are linked together to form a ring, the formed ring may contain one to three heteroatoms selected from the group consisting of N, O, and S.

[0153] As a specific example, in equation (D), B 1 and B 2 Each of these is independently 1 to 10 alkylene groups, and R 32 ~R 35 Each of these is an alkyl group having 1 to 10 carbon atoms, and L 1 ~L 4 These are, independently, a tetravalent alkylsilyl group substituted with an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or L 1 and L 2 And, L 3 and L 4 These may be linked together to form a ring with 1 to 3 carbon atoms, L 1 and L 2 And, L 3 and L 4 When these elements are linked together to form a ring, the formed ring may contain one to three heteroatoms selected from the group consisting of N, O, and S.

[0154] The coupling modifier represented by formula (A) is not particularly limited, but examples include 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine, 1-methyl-4-[3-(triethoxysilyl)propyl]piperazine, 1-propyl-4-[3-(trimethoxysilyl)propyl]piperazine, 1-propyl-4-[3-(triethoxysilyl)propyl]piperazine, 1-trimethylsilyl-4-[3-(trimethoxysilyl)propyl]piperazine, and 1-trimethylsilyl-4-[3-(triethoxysilyl)propyl]piperazine.

[0155] Among these, those in formula (A) where d is 6 are preferred from the viewpoint of enhancing the reactivity and interaction between the conjugated diene polymer and inorganic fillers such as silica, and from the viewpoint of improving processability. Specifically, 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine and 1-methyl-4-[3-(triethoxysilyl)propyl]piperazine are preferred.

[0156] In the coupling step using the coupling modifier represented by formula (A), the reaction temperature and reaction time are not particularly limited, but are preferably 0°C to 120°C and preferably 30 seconds or longer.

[0157] The amount of coupling modifier represented by formula (A) added is preferably in a range where the total number of moles of alkoxy groups bonded to the silyl groups in the coupling modifier represented by formula (A) is between 0.2 and 2.0 times the number of moles of polymerization initiator added, more preferably between 0.5 and 1 time, and even more preferably between 0.6 and 0.8 times. From the viewpoint of making the nitrogen content and / or silicon content, molecular weight, and branched structure of the resulting modified conjugated diene polymer even more favorable, it is preferable to set it to 0.2 times or more. Furthermore, from the viewpoint of suppressing a decrease in processability due to an excessively high number of branches, it is preferable to set it to 2.0 times or less.

[0158] More specifically, the amounts of polymerization initiator and coupling modifier represented by formula (A) should be adjusted so that the number of moles of polymerization initiator is preferably 0.25 times or more, more preferably 0.3 times or more, than the number of moles of coupling modifier represented by formula (A).

[0159] In the coupling modifier represented by formula (B), A in formula (B) is preferably a structure represented by any of the following formulas (I) to (III).

[0160] [ka] (In formula (I), D 1 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, and h represents an integer from 1 to 10. D is used when multiple groups exist. 1 These can be independent of each other, and may be the same or different.

[0161] [ka] (In formula (II), D 2 This represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, D 3 represents an alkyl group with 1 to 20 carbon atoms, and h represents an integer from 1 to 10. D is used when multiple such elements exist. 2 and D 3 These can be independent of each other, and may be the same or different.

[0162] [ka] (In formula (III), D 4 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, and h represents an integer from 1 to 10. D is used when multiple groups exist. 4 These can be independent of each other, and may be the same or different.

[0163] [ka] (In formula (IV), D5 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, and h represents an integer from 1 to 10. D is used when multiple groups exist. 5 These can be independent of each other, and may be the same or different.

[0164] In the coupling modifier represented by formula (B), the coupling modifier when A in formula (B) is represented by formula (I) is not particularly limited, but for example, tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza- [2-Silacyclopentane)propyl]amine, Tris(3-ethoxysilylpropyl)amine, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, Bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)amine, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, Tetrakis(3-trimethoxysilylpropyl)-1,3-propanedi Amine, Tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-propanediamine, Tetrakis[3-(2,2-dimethoxy- 1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,[2-Dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, Tris(3 (3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl)-1,3-propanediamine, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl] [Pyr]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl Tris[3-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, Tris(3-trimethoxysilylpropyl)-[3-(2,[2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane) [3-(1-methoxy-2-trimethylsilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-dimethoxy [-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-triethoxysilylpropyl)-1,3-propane Diamine, Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, Bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, Tetrakis[3-(2,[2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-aza-2-silacyclo Examples include pentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, and pentakis(3-trimethoxysilylpropyl)-diethylenetriamine.

[0165] In the coupling modifier represented by formula (B), the coupling modifier when A in formula (B) is represented by formula (II) is not particularly limited, but examples include tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] -(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N 1 ,N 1 '-(propane-1,3-diyl)bis(N 1 -methyl-N 3 ,N 3 -Bis(3-(trimethoxysilyl)propyl)-1,3-propanediamine), and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propanediamine is one example.

[0166] In the coupling modifier represented by formula (B), the coupling modifier when A in formula (B) is represented by formula (III) is not particularly limited, but examples include tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2-sil [3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-sila [Clopentane)propyl]silane, bis[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1 Examples include -sila-2-azacyclopentane)propyl]-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, bis[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-bis(3-trimethoxysilylpropyl)silane, and bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]silane.

[0167] In the coupling modifier represented by formula (B), the coupling modifier when A in formula (B) is represented by formula (IV) is not particularly limited, but examples include 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silacyclopentane)propane and 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane.

[0168] In the coupling modifier represented by formula (B), A in formula (B) is more preferably the structure represented by formula (I) or formula (II), and more preferably k is 0. Modified conjugated diene polymers obtained using such coupling modifiers tend to have even better wear resistance and low hysteresis loss when vulcanized. Such coupling modifiers are not particularly limited, but examples include bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1- Examples include aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, and bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trismethoxysilylpropyl)-methyl-1,3-propanediamine.

[0169] In the coupling modifier represented by formula (B), A in formula (B) is more preferably the structure represented by formula (I) or formula (II), more preferably k is 0, and in formula (I) or formula (II), more preferably h is an integer from 2 to 10. Modified conjugated diene polymers obtained using such coupling modifiers tend to have even better wear resistance and low hysteresis loss when vulcanized. Such coupling modifiers are not particularly limited, but examples include tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propanediamine is one example.

[0170] The amount of coupling modifier represented by formula (B) added is preferably determined based on the ratio of the number of moles of polymerization initiator added to the number of moles of coupling modifier represented by formula (B). In this way, the reaction between the conjugated diene polymer and the modifier can be adjusted to a desired stoichiometric ratio.

[0171] More specifically, the amounts of the polymerization initiator and the coupling modifier represented by formula (B) should be adjusted so that the number of moles of the coupling modifier represented by formula (B) is preferably 0.1 to 2.0 times, more preferably 0.15 to 1.0 times, relative to the number of moles of the polymerization initiator. In this case, the number of functional groups of the coupling modifier represented by formula (B) (for example, when i and j are 2 or more, and there are multiple w and x, and their f and g are equal, then f × i + (g + 1) × j + k) is preferably an integer between 5 and 10, and more preferably an integer between 6 and 10. From the viewpoint of making the nitrogen content and / or silicon content, molecular weight, and branched structure of the resulting modified conjugated diene polymer even more favorable, it is preferable to set it to 0.2 times or more. Also, from the viewpoint of suppressing a decrease in fracture properties due to an excessively high number of branches, it is preferable to set it to 0.5 times or less.

[0172] The coupling modifier represented by formula (C) is not particularly limited, but examples include tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-methyldiethoxysilylpropyl)amine, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine.

[0173] Among these, those in formula (C) where n, m, and l are all 3 are preferred from the viewpoint of enhancing the reactivity and interaction between the modified conjugated diene polymer and inorganic fillers such as silica, as well as from the viewpoint of improving processability. Specifically, examples include tris(3-trimethoxysilylpropyl)amine and tris(3-triethoxysilylpropyl)amine.

[0174] In the coupling step using the coupling modifier represented by formula (C), the reaction temperature and reaction time are not particularly limited, but are preferably 0°C to 120°C and preferably 30 seconds or longer.

[0175] The amount of the coupling modifier represented by the formula (C) is preferably in the range where the total number of moles of the alkoxy groups bonded to the silyl group in the coupling modifier represented by the formula (C) is 0.1 times or more and 2.0 times or less the number of moles of the polymerization initiator added, more preferably in the range of 0.2 times or more and 1.0 times or less, and even more preferably in the range of 0.3 times or more and 0.5 times or less. From the viewpoint of making the nitrogen content and / or silicon content, molecular weight, and branched structure of the obtained modified conjugated diene polymer more preferable, it is preferably 0.1 times or more. Also, from the viewpoint of suppressing the decrease in fracture properties due to an excessive increase in the number of branches, it is preferably 2.0 times or less.

[0176] The coupling modifier represented by the formula (D) is not particularly limited. For example, 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dipropylpropane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropane-1-amine) can be mentioned.

[0177] Regarding the reaction temperature and reaction time in the coupling step using the coupling modifier represented by the formula (D), they are not particularly limited, but are preferably 0°C or higher and 120°C or lower, and preferably 30 seconds or longer.

[0178] The addition amount of the coupling modifier represented by formula (D) is preferably in the range where the total number of moles of the alkoxy groups bonded to the silyl groups in the coupling modifier represented by formula (D) is 0.25 times or more and 2.0 times or less the number of moles of the polymerization initiator added, more preferably in the range of 0.3 times or more and 1.0 times or less, and even more preferably in the range of 0.35 or more and 0.5 times or less. From the viewpoint of making the nitrogen content and / or silicon content, molecular weight, and branched structure of the obtained modified conjugated diene polymer more preferable, it is preferably 0.25 times or more. Also, from the viewpoint of suppressing the decrease in processability due to an excessive increase in the number of branches, it is preferably 2.0 times or less.

[0179] The production method of this embodiment may further include a condensation reaction step of causing a condensation reaction by adding a condensation accelerator after and / or before the coupling step.

[0180] In the production method of this embodiment, after the coupling step, a deactivator and / or a neutralizing agent, etc. may be further added to the polymer solution as necessary.

[0181] The deactivator is not particularly limited, and examples thereof include water and alcohols such as methanol, ethanol, and isopropanol.

[0182] The neutralizing agent is not particularly limited, and examples thereof include carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of highly branched carboxylic acids having 9 to 11 carbon atoms and having 10 carbon atoms as the main component), aqueous solutions of inorganic acids, and carbon dioxide gas.

[0183] The manufacturing method of this embodiment may further include a step of obtaining the modified conjugated diene polymer from the polymer solution. Known methods can be used for this purpose, but for example, the following methods may be used: a method of obtaining the polymer by separating the solvent by steam stripping or the like, filtering off the polymer, and then dehydrating and drying it; a method of obtaining the polymer by concentrating it in a flushing tank and then defoliating it with a vent extruder or the like; and a method of obtaining the polymer by directly defoliating it with a drum dryer or the like.

[0184] (Modified conjugated diene polymer composition) The conjugated diene polymer composition of this embodiment contains 100 parts by mass of a modified conjugated diene polymer and 1.0 part by mass to 60 parts by mass of a rubber softener. By adding the rubber softener to the modified conjugated diene polymer of this embodiment, a composition with improved processability when compounded with fillers and the like can be obtained.

[0185] Rubber softeners are not particularly limited, but examples include stretching oils, liquid rubber, and resins.

[0186] Examples of 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 improving wet grip. Aromatic substitute oils are not particularly limited, but examples include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts) as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0187] The liquid rubber is not particularly limited, but examples include liquid polybutadiene and liquid styrene-butazine rubber.

[0188] When liquid rubber is used as a rubber softener, in addition to the effects described above, the glass transition temperature of the modified conjugated diene polymer composition can be lowered, which tends to further improve the wear resistance, low hysteresis loss, and low-temperature properties of the vulcanized product.

[0189] The resins are not particularly limited, but examples include 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, aromatic hydrocarbon resins, aromatic petroleum resins, 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. These resins may be used individually or in combination of two or more. Furthermore, when hydrogenating these resins, all unsaturated groups may be hydrogenated, or some may be left intact.

[0190] When resin is used as a rubber softener, in addition to the effects described above, the fracture strength of the vulcanized product of the modified conjugated diene polymer composition tends to be further improved.

[0191] The amount of rubber softener added is not particularly limited as long as it is 1.0 part by mass or more and 60 parts by mass or less per 100 parts by mass of the modified conjugated diene polymer of this embodiment, but preferably 3.0 parts by mass or more and 50 parts by mass or less, more preferably 5.0 parts by mass or more and 40 parts by mass or less, and even more preferably 10 parts by mass or more and 35 parts by mass or less. Adding rubber softener within the above range tends to further improve the processability when fillers and the like are blended, and further improve the fracture strength and abrasion resistance of the vulcanized product.

[0192] There are no particular limitations on the method of adding a rubber softener to a modified conjugated diene polymer, but one example is to add the rubber softener to a modified conjugated diene polymer solution, mix it, and then desolvate the polymer solution.

[0193] The modified conjugated diene polymer composition of this embodiment may further contain a rubber stabilizer from the viewpoint of suppressing gel formation and improving stability during processing.

[0194] The rubber stabilizer is not particularly limited and known stabilizers can be used, but examples include antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propinate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0195] (Rubber composition) The rubber composition of this embodiment comprises a rubber component containing 50 parts by mass or more of a modified conjugated diene polymer, and a filler in an amount of 5.0 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the rubber component. By dispersing the filler in the rubber component containing the modified conjugated diene polymer of this embodiment, a rubber composition can be obtained that exhibits even better processability during vulcanization, and whose vulcanized product has even better low hysteresis loss, fracture characteristics, and abrasion resistance. Furthermore, by including the modified conjugated diene polymer composition of this embodiment in a predetermined proportion of the rubber component, fuel efficiency, processability, and abrasion resistance are further improved.

[0196] The filler is not particularly limited, but examples include silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. In particular, when the rubber composition of this embodiment is used for vulcanized rubber applications such as tires, vibration-damping rubber for automobile parts, and shoes, it is especially preferable to include a silica-based inorganic filler. Such fillers may be used alone or in combination of two or more.

[0197] The silica-based inorganic filler is not particularly limited, and known fillers can be used, but 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 in an amount of more than 50% by mass, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0198] Specific silica-based inorganic fillers are not particularly limited, but examples include silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and inorganic fibrous materials such as glass fibers. Alternatively, silica-based inorganic fillers with hydrophobic surfaces and mixtures of silica-based and non-silica-based inorganic fillers may be used. Among these, silica or glass fibers are preferred, and silica is more preferred, from the viewpoint of further improving the strength and abrasion resistance of the rubber composition. Silica is not particularly limited, but examples include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred from the viewpoint of further improving the fracture strength of the rubber composition.

[0199] From the viewpoint of more reliably obtaining rubber compositions with practically good abrasion resistance and fracture strength, the nitrogen adsorption specific surface area required by the BET adsorption method of silica-based inorganic fillers is 100 m². 2 / g or more 300m 2 It is preferable that it be less than or equal to / g, and 170m 2 / g or more 250m 2 It is more preferable that the specific surface area be less than or equal to / g. Also, if necessary, a relatively small specific surface area (for example, a specific surface area of ​​200m²) 2 Silica-based inorganic fillers (less than / g) and those with a relatively large specific surface area (for example, 200m²) 2 It may also be used in combination with silica-based inorganic fillers (1 / g or more). In this embodiment, in particular, a relatively large specific area (for example, 200m) 2When using a silica-based inorganic filler of / g or more, the modified conjugated diene polymer composition is particularly excellent in the dispersibility of silica. As a result, the resulting rubber composition tends to have more excellent abrasion resistance, fracture strength, and low hysteresis loss properties.

[0200] The carbon black is not particularly limited, and examples thereof include carbon blacks of each class such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area determined by the BET adsorption method of 50 m 2 / g or more and an oil absorption amount of dibutyl phthalate (DBP) of 80 mL / 100 g or less is preferable.

[0201] As the metal oxide, there is no particular limitation as long as it is solid particles having a main component of a structural unit of the chemical formula M x O y (M represents a metal atom, and x and y each independently represent an integer of 1 to 6). Examples thereof include alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0202] The metal hydroxide is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0203] The content of the filler in the rubber composition of the present embodiment is preferably 5.0 parts by mass or more and 150 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less, and even more preferably 30 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. When the filler is within the above range, the rubber composition is more excellent in processability during vulcanization, and the vulcanizate tends to have more excellent low hysteresis loss properties, fracture characteristics, and abrasion resistance.

[0204] From the viewpoint of reliably imparting performance required for applications such as tires, such as dry grip performance and conductivity, the rubber composition of this embodiment preferably contains carbon black in an amount of 0.5 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the rubber component containing the modified conjugated diene polymer. From a similar viewpoint, the rubber composition preferably contains carbon black in an amount of 3.0 parts by mass or more and 100 parts by mass or less, and even more preferably 5.0 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the rubber component containing the modified conjugated diene polymer.

[0205] The rubber composition of this embodiment may further contain a silane coupling agent. By including a silane coupling agent in the rubber composition, the interaction between the rubber component and the filler can be further improved. The silane coupling agent is not particularly limited, but for example, compounds having a sulfur bond moiety and an alkoxysilyl group or silanol group moiety in one molecule are preferred. Examples of such compounds are not particularly limited, but include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0206] In the rubber composition of this embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 part by mass or more and 15 parts by mass or less, per 100 parts by mass of the filler. When the content of the silane coupling agent is within the above range, the interaction between the rubber component and the filler tends to be further improved.

[0207] The rubber composition of this embodiment may also contain rubbery polymers other than the modified conjugated diene polymer of this embodiment (hereinafter simply referred to as "rubbery polymers") as rubbery components.

[0208] Examples of rubbery polymers include, but are not limited to, conjugated diene polymers and their hydrogenated products, random copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenated products, block copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenated products, non-diene polymers, and natural rubber.

[0209] Specific examples of rubbery polymers include, but are not limited to, styrene-based elastomers such as butadiene rubber and its hydrogenated derivatives, isoprene rubber and its hydrogenated derivatives, styrene-butadiene rubber and its hydrogenated derivatives, styrene-butadiene block copolymers and their hydrogenated derivatives, and styrene-isoprene block copolymers and their hydrogenated derivatives, as well as acrylonitrile-butadiene rubber and its hydrogenated derivatives.

[0210] Examples of non-diene polymers include olefin-based elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, as well as butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0211] Examples of natural rubber include, but are not limited to, smoked sheets such as RSS3-5, SMR, and epoxidized natural rubber.

[0212] The rubbery polymer may be a modified rubber to which polar functional groups such as hydroxyl groups and amino groups have been added. When the rubber composition of this embodiment is used for tires, the rubbery polymer is preferably one or more selected from the group consisting of butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber.

[0213] The weight-average molecular weight (Mw) of the rubbery polymer is preferably 2,000 to 2,000,000, and more preferably 5,000 to 1,500,000, from the viewpoint of balancing the abrasion resistance, fracture strength, low hysteresis loss, and processability of the rubber composition. Furthermore, low molecular weight rubbery polymers, so-called liquid rubber, can also be used as the rubbery polymer. These rubbery polymers may be used individually or in combination of two or more.

[0214] When the rubber composition of this embodiment contains the modified conjugated diene polymer and the rubbery polymer of this embodiment, the content ratio (mass ratio) of the modified conjugated diene polymer to the rubbery polymer is preferably 50 / 50 or more and 100 / 0 or less, more preferably 55 / 45 or more and 95 / 5 or less, even more preferably 60 / 40 or more and 90 / 10 or less, and particularly preferably 65 / 35 or more and 85 / 15 or less. That is, the rubber component contains, per 100 parts by mass of the total amount of the rubber component, preferably 50 parts by mass or more and 100 parts by mass or less, more preferably 55 parts by mass or more and 95 parts by mass or less, even more preferably 60 parts by mass or more and 90 parts by mass or less, and particularly preferably 65 parts by mass or more and 85 parts by mass or less of the modified conjugated diene polymer of this embodiment. When the proportion of the conjugated diene polymer contained in the rubber component is within the above range, the vulcanized product of the rubber composition tends to be even better in terms of abrasion resistance and low hysteresis loss.

[0215] From the viewpoint of further improving its processability, the rubber composition of this embodiment may contain a rubber softener in addition to the rubber component.

[0216] As rubber softeners, the same substances exemplified as those included in the conjugated diene polymer composition can be used, but mineral oil or liquid or low molecular weight synthetic softeners are preferred.

[0217] Mineral oil-based rubber softeners, also known as process oils or extender oils, used to soften, increase the volume of, and improve the processability of rubber are mixtures of aromatic rings, naphthenic rings, and paraffinic chains. Among these, those in which the number of carbon atoms belonging to the paraffinic chain is 50% or more of the total number of carbon atoms are called paraffinic, those in which the number of carbon atoms belonging to the naphthenic ring is 30% to 45% of the total number of carbon atoms are called naphthenic, and those in which the number of carbon atoms belonging to the aromatic ring is more than 30% of the total number of carbon atoms are called aromatic. The rubber composition of this embodiment preferably contains a rubber softener having an appropriate aromatic content. Including such a rubber softener further improves compatibility with the modified conjugated diene polymer.

[0218] The amount of rubber softener in a rubber composition is expressed as the total amount of rubber softener added to the modified conjugated diene polymer composition or rubbery polymer beforehand, plus the amount of rubber softener added when forming the rubber composition.

[0219] In the rubber composition of this embodiment, the content of the rubber softener is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and even more preferably 30 to 90 parts by mass, per 100 parts by mass of the rubber component. By having a rubber softener content of 100 parts by mass or less per 100 parts by mass of the rubber component, bleed-out can be suppressed and stickiness on the surface of the rubber composition can be further suppressed.

[0220] The method for mixing modified conjugated diene polymers, modified conjugated diene polymer compositions, rubbery polymers, fillers, silane coupling agents, and / or rubber softeners is not particularly limited, 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. Of these, the melt-kneading method using a roll, Banbury mixer, kneader, or extruder is preferred from the viewpoint of productivity and good kneadability. Furthermore, the rubber components, fillers, silane coupling agents, and additives may be kneaded all at once, or they may be mixed in multiple stages.

[0221] The rubber composition of this embodiment may be a vulcanized product that has been vulcanized with a vulcanizing agent. The vulcanizing agent is not particularly limited, but examples include radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high molecular weight polysulfur compounds.

[0222] In the rubber composition of this embodiment, the content of the vulcanizing agent is not particularly limited, but 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. A conventionally known method can be used as the vulcanization method. Furthermore, the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.

[0223] When vulcanizing a rubber composition, a vulcanization accelerator and / or vulcanization aid may be used as needed. While conventionally known materials can be used as vulcanization accelerators, they are not particularly limited. Examples include sulfenamide, guanidine, thiuram, aldehyde-amine, aldehyde-ammonia, thiazole, thiourea, and dithiocarbamate vulcanization accelerators. Similarly, while not particularly limited, examples of vulcanization aids include zinc oxide and stearic acid. The content of the vulcanization accelerator and vulcanization aid is not particularly limited, but 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.

[0224] The rubber composition of this embodiment may contain various additives other than those described above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, to the extent that they do not impair the effects of this embodiment. Known softeners can be used as softeners. There are no particular limitations on fillers, but examples include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants.

[0225] The rubber composition of this embodiment is suitably used as a rubber composition for tires. The rubber composition of this embodiment is not particularly limited, but can be suitably used in various types of tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires; and in various parts of the tire such as the tread, carcass, sidewall, and bead.

[0226] Furthermore, the numerical ranges described above as preferred ranges may be replaced with any combination of the values ​​listed as upper and lower limits, unless otherwise specified. [Examples]

[0227] The present invention will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples.

[0228] The various physical properties in the examples and comparative examples were measured by the methods described below.

[0229] (Physical property 1) Average molecular weight measured by GPC method GPC measurements were performed using a modified conjugated diene polymer as the sample, employing a GPC analyzer (product name "HLC-8320GPC" manufactured by Tosoh Corporation) with three columns packed with polystyrene gel, and a refractive index (RI) detector (product name "HLC8020" manufactured by Tosoh Corporation). Based on a calibration curve obtained using standard polystyrene, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn), which is the ratio of these two values, were determined. The eluent used was a 5 mmol / L triethylamine-THF (tetrahydrofuran) solution. Three TSKgel SuperMultiporeHZ-H columns, manufactured by Tosoh Corporation, were connected together, and a TSKguardcolumn SuperMP(HZ)-H column, also manufactured by Tosoh Corporation, was connected before them as a guard column. 10 mg of the sample for measurement was dissolved in 10 mL of THF to prepare the measurement solution. 10 μL of the measurement solution was injected into the GPC analyzer, and measurements were taken under the conditions of an oven temperature of 40°C and a THF flow rate of 0.35 mL / min. The measured results were defined as the average molecular weight of each sample.

[0230] (Physical properties 2) Polymer Mooney viscosity A modified conjugated diene polymer was used as a sample, and the Mooney viscosity was measured using a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) with an L-shaped rotor in accordance with ISO 289. The measurement temperature was set to 100°C. Here, the sample was preheated to the test temperature for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to determine the Mooney viscosity (ML). (1+4) The temperature (100℃) was measured.

[0231] (Physical property 3) Mooney relaxation rate Using a modified conjugated diene polymer as a sample, a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used to measure the aforementioned Mooney viscosity in accordance with ISO 289 using an L-shaped rotor. Immediately after measuring, the rotor rotation was stopped, and the torque was recorded in Mooney units at 0.1-second intervals from 1.6 seconds to 5 seconds after stopping. The slope of the line when torque and time (seconds) were plotted on a log-log scale was determined, and its absolute value was defined as the Mooney relaxation rate (MSR, 100°C).

[0232] (Physical property 4) Silicon content As an ICP analysis method, the silicon (Si) content was measured using an inductively coupled plasma emission spectrometer (ICP-OES; Optima7300DV). When using the inductively coupled plasma emission spectrometer, approximately 0.7 g of the sample was placed in a platinum crucible, approximately 1 mL of concentrated sulfuric acid (98 wt%) was added, and the sample was heated at 300°C for 3 hours. The sample was then ashed in an electric furnace using the following programs 1 to 3. 1) Step 1: Start at 0°C, raise temperature to 180°C / hr, then maintain temperature at 180°C for 1 hour. 2) Step 2: Start at 180°C, increase temperature at 85°C / hr, then maintain temperature at 370°C for 2 hours. 3) Step 3: Start at 370°C, increase temperature at 47°C / hr, then maintain temperature at 510°C for 3 hours. To the residue, add 1 mL of concentrated nitric acid (48% by weight) and 20 μl of concentrated hydrofluoric acid (50% by weight). After sealing the platinum crucible and shaking for at least 30 minutes, add 1 mL of boric acid to the sample and store at 0°C for at least 2 hours. Then, dilute with 30 mL of ultrapure water and allow ashing to proceed to measure the silicon (Si) content.

[0233] (Physical property 5) Nitrogen content The nitrogen (N) content is measured using a trace nitrogen quantitative analyzer (NSX-2100H). When using the trace nitrogen quantitative analyzer, the analyzer is turned on, the carrier gas flow rates are set to 250 ml / min for Ar, 350 ml / min for O2, and 300 ml / min for the ozonizer, the heater is set to 800°C, and the analyzer is allowed to stabilize for approximately 3 hours. After the analyzer has stabilized, calibration curves are created using standard samples at calibration ranges of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 500 ppm. After obtaining the area corresponding to each concentration, a straight line is created using the ratio of concentration to area. Then, a ceramic boat containing 20 mg of the sample is placed in the auto sampler of the analyzer and measured to obtain the area. The nitrogen (N) content is calculated using the obtained sample area and the calibration curve. In this process, the sample is a modified conjugated diene polymer that has been stirred in steam-heated hot water to remove the solvent, and from which residual monomers, residual modifiers, and oil have been removed.

[0234] (Physical property 6) Degeneration rate The denaturation rate of modified conjugated diene polymers was measured as follows using the column adsorption GPC method. The column adsorption GPC method is a method for determining the denaturation rate of modified conjugated diene polymers by utilizing the property that modified basic polymer components in modified conjugated diene polymers are easily adsorbed onto a GPC column packed with silica gel. Modified conjugated diene polymers were used as samples, and the sample solution containing the sample and a low molecular weight internal standard polystyrene was measured using a polystyrene column. The same sample solution was also measured using a silica column. The amount of modified conjugated diene polymer adsorbed onto the silica column was determined by calculating the difference between the chromatograms obtained using the polystyrene column and the chromatograms obtained using the silica column, thereby determining the modification rate. Specifically, 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare the sample solution. The modification rate of the modified conjugated diene polymer was measured under the following measurement conditions.

[0235] (GPC measurement conditions using polystyrene columns) GPC measurements were performed using the "HLC-8320GPC" product (manufactured by Tosoh Corporation) and an RI detector ("HLC8020" product (manufactured by Tosoh Corporation)). A 5 mmol / L triethylamine-THF solution was used as the eluent, and 10 μL of the sample solution was injected into the GPC instrument. A chromatogram was obtained under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.35 mL / min. The column consisted of three "TSKgel SuperMultiporeHZ-H" columns manufactured by Tosoh Corporation, with a "TSKguardcolumn SuperMP(HZ)-H" column, also manufactured by Tosoh Corporation, connected before them as a guard column.

[0236] (GPC measurement conditions using silica-based columns) GPC measurements were performed using the "HLC-8320GPC" product (manufactured by Tosoh Corporation) and an RI detector ("HLC8020" product (manufactured by Tosoh Corporation)). Using THF as the eluent, 50 μL of the sample solution was injected into the apparatus, and a chromatogram was obtained under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were Agilent's "Zorbax PSM-1000S," "PSM-300S," and "PSM-60S," connected in that order, with a "DIOL 4.6×12.5mm 5micron" column connected before them as a guard column.

[0237] How to calculate the rate of degeneration: For chromatograms obtained using polystyrene columns, the peak area P1 of the sample and the peak area P2 of standard polystyrene were determined, with the total peak area set to 100. Similarly, for chromatograms obtained using silica columns, the peak area P3 of the sample and the peak area P4 of standard polystyrene were determined, with the total peak area set to 100. The denaturation rate (mass%) was then calculated using the following formula. Degeneration rate (mass%) = [1 - (P2 × P3) / (P1 × P4)] × 100 (However, P1+P2=P3+P4=100)

[0238] (Physical property 7) Amount of bonded aromatic vinyl (amount of bonded styrene) Modified conjugated diene polymers were used as samples. 100 mg of the sample was dissolved in 100 mL of chloroform to prepare the measurement sample. Each sample was measured using a spectrophotometer (Shimadzu Corporation, product name "UV-2450"), and the absorption spectrum was obtained. From the absorbance of ultraviolet light (around 254 nm) originating from the phenyl group of styrene, the amount of bound styrene (mass%) relative to 100% by mass of the modified conjugated diene polymer was calculated.

[0239] (Physical property 7) Amount of vinyl bonds in bonded conjugated dienes (Amount of 1,2-vinyl bonds in bonded butadiene) Modified conjugated diene polymers were used as samples. 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare the measurement sample. The infrared spectra of each sample were measured at 600-1000 cm⁻¹. -1 Measurements were taken within the specified range using a Fourier transform infrared spectrophotometer (product name "FT-IR230" manufactured by JASCO Corporation). The amount of 1,2-vinyl bond in the bonded butadiene (mol%) was determined from the absorbance at a predetermined wavenumber using Hampton's method (as described in RRHampton, Analytical Chemistry 21, 923 (1949)).

[0240] (Physical property 8) Glass transition temperature Modified conjugated diene polymers were used as samples, and DSC measurements were performed using a differential scanning calorimeter (product name "DSC3200S" manufactured by MacScience Corporation) in accordance with ISO 22768:2006. Under a helium flow of 50 mL / min, the DSC curve was recorded while increasing the temperature from -100°C at 20°C / min, and the peak top (inflection point) of the DSC differential curve was defined as the glass transition temperature (Tg).

[0241] (Physical properties 9) Phase difference index Approximately 6 g of a modified conjugated diene polymer was prepared as a sample. Each sample was measured using an ALPHATECHNOLOGIES RUBBERPROCESSANALYZER RPA2000, and the tanδ value at 0.1 Hz obtained at 160°C and 7% strain was determined as the phase difference index.

[0242] (Example 1) Modified conjugated diene polymer (A1) Two tank-type pressure vessels, each with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L / D) of 4.0, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a jacket for temperature control, were connected together as polymerization branching reactors. 1,3-butadiene, styrene, and n-hexane, from which water had been removed beforehand, were continuously supplied to the bottom of the first reactor at rates of 22.3 g / min, 3.4 g / min, and 100.4 g / min, respectively, while being mixed. Immediately before the mixed solution entered the first reactor, n-butyllithium was continuously added at a rate of 0.104 mmol / min using a static mixer to inactivate any remaining impurities. Simultaneously with the supply of 1,3-butadiene, styrene, n-hexane, and n-butyllithium, 2,2-bis(2-oxolanil)propane as a polar compound and n-butyllithium as a polymerization initiator were supplied to the bottom of the first reactor at rates of 0.094 mmol / min and 0.234 mmol / min, respectively, while the reaction solution was vigorously stirred with a stirrer. The temperature inside the first reactor was maintained at 68°C.

[0243] The conjugated diene polymer solution produced by the polymerization reaction in the first reactor was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor. The solution continuously withdrawn from the top of the first reactor showed sufficient polymerization stability. Simultaneously with the supply of the conjugated diene polymer solution from the bottom of the second reactor, trimethoxy(4-vinylphenyl)silane (referred to as "a1" in Table 1) was supplied as a branching agent at a rate of 0.012 mmol / min. An additional 1,3-butadiene was added at a rate of 7.4 g / min. The temperature inside the second reactor was maintained at 73°C. A small amount of the conjugated diene polymer solution was withdrawn from the outlet of the second reactor, and antioxidant (BHT) was added so that the antioxidant content was 0.2 g per 100 g of conjugated diene polymer, after which the solvent was removed.

[0244] Next, the conjugated diene polymer solution with a branched structure, generated by a branching reaction in the second reactor, was continuously withdrawn from the top of the second reactor and continuously supplied to the bottom of the second reactor. The conjugated diene polymer with a branched structure was coupled to the polymer solution flowing continuously in a static mixer by continuously adding tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) at a rate of 0.011 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) at a rate of 0.102 mmol / min as coupling modifiers. The time from the outflow of the second reactor to the addition of the coupling modifiers was 4.8 minutes, and the temperature of the polymer solution at the time of addition was 68°C. Furthermore, the temperature difference between the polymer solution at the outlet of the second reactor and the polymer solution at the time of addition of the coupling modifiers was 2°C. A small amount of the modified conjugated diene polymer solution was withdrawn after coupling, and antioxidant (BHT) was added to a concentration of 0.2 g per 100 g of the modified conjugated diene polymer. The solvent was then removed. The amount of bound styrene (physical property 7) and the amount of 1,2-vinyl bonds in the bound butadiene (physical property 7) of the obtained modified conjugated diene polymer were measured. The measurement results are shown in Table 1.

[0245] Next, to the polymer solution effluent from the static mixer, an n-hexane solution of antioxidant (BHT) was continuously added at a rate of 0.055 g / min, such that the antioxidant (BHT) content was 0.2 g per 100 g of modified conjugated diene polymer, thereby terminating the coupling reaction. By removing the solvent by steam stripping, the modified conjugated diene polymer (A1) was obtained. The physical properties of the modified conjugated diene polymer (A1) are shown in Table 1.

[0246] (Example 2) Modified conjugated diene polymer (A2) A modified conjugated diene polymer (A2) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.3 g / min, styrene at 6.5 g / min, n-butyllithium as a polymerization initiator at 0.239 mmol / min, an additional 1,3-butadiene at 5.8 g / min, and b2 as a coupling modifier at 0.105 mmol / min. The properties of the modified conjugated diene polymer (A2) are shown in Table 1.

[0247] (Example 3) Modified conjugated diene polymer (A3) A modified conjugated diene polymer (A3) was obtained in the same manner as in Example 2, except that 1,3-butadiene was supplied at a rate of 22.3 g / min, styrene at 3.4 g / min, an additional 1,3-butadiene at 7.4 g / min, and 2,2-bis(2-oxolanil)propane as a polar compound at 0.062 mmol / min, the temperature of the first reactor was set to 82°C, and the temperature of the second reactor was set to 86°C. The properties of the modified conjugated diene polymer (A3) are shown in Table 1.

[0248] (Example 4) Modified conjugated diene polymer (A4) Two tank-type pressure vessels, each with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L / D) of 4.0, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a jacket for temperature control, were connected together as polymerization branching reactors. 1,3-butadiene, styrene, and n-hexane, from which water has been removed, were continuously supplied to the bottom of the first reactor at rates of 22.3 g / min, 3.4 g / min, and 100.4 g / min, respectively, while being mixed. Immediately before the mixed solution entered the first reactor, n-butyllithium was continuously added at a rate of 0.104 mmol / min using a static mixer to inactivate any remaining impurities. Simultaneously with the supply of 1,3-butadiene, styrene, n-hexane, and n-butyllithium, 2,2-bis(2-oxolanil)propane as a polar compound and n-butyllithium as a polymerization initiator were supplied to the bottom of the first reactor at rates of 0.094 mmol / min and 0.234 mmol / min, respectively, while the reaction solution was vigorously stirred with a stirrer. The temperature inside the first reactor was maintained at 68°C.

[0249] The conjugated diene polymer solution produced by the polymerization reaction in the first reactor was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor. An additional 1,3-butadiene was added at a rate of 7.4 g / min. The temperature in the second reactor was maintained at 73°C. A small amount of the conjugated diene polymer solution was withdrawn from the outlet of the second reactor, and antioxidant (BHT) was added so that the antioxidant content was 0.2 g per 100 g of conjugated diene polymer, after which the solvent was removed.

[0250] Next, the conjugated diene polymer solution produced in the second reactor was continuously withdrawn from the top of the second reactor and continuously supplied to the bottom of the second reactor. The conjugated diene polymer was coupled to the polymer solution flowing continuously in the static mixer by continuously adding tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) at a rate of 0.019 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) at a rate of 0.075 mmol / min as coupling modifiers. At this time, the time until the coupling modifier was added to the polymer solution flowing out of the outlet of the second reactor was 4.8 minutes, and the temperature of the polymer solution at the time of addition of the coupling modifier was 68°C. Furthermore, the difference between the temperature of the polymer solution at the outlet of the second reactor and the temperature of the polymer solution when the coupling modifier was added was 2°C. A small amount of the modified conjugated diene polymer solution was withdrawn after coupling, and antioxidant (BHT) was added so that the antioxidant content was 0.2 g per 100 g of the modified conjugated diene polymer, after which the solvent was removed. The amount of bound styrene (physical property 7) and the amount of 1,2-vinyl bonds in the bound butadiene (physical property 7) of the obtained modified conjugated diene polymer were measured. The measurement results are shown in Table 1.

[0251] Next, to the polymer solution effluent from the static mixer, an n-hexane solution of antioxidant (BHT) was continuously added at a rate of 0.055 g / min, such that the antioxidant (BHT) content was 0.2 g per 100 g of modified conjugated diene polymer, thereby terminating the coupling reaction. By removing the solvent by steam stripping, the modified conjugated diene polymer (A4) was obtained. The physical properties of the modified conjugated diene polymer (A4) are shown in Table 1. Note that the structure of the modified conjugated diene polymer was identified for the polymer after the addition of the coupling modifier. The structure of each sample was identified in the same manner below.

[0252] (Example 5) Modified conjugated diene polymer (A5) A modified conjugated diene polymer (A5) was obtained in the same manner as in Example 1, except that 2,2-bis(2-oxolanil)propane was supplied as a polar compound at a rate of 0.152 mmol / min. The properties of the modified conjugated diene polymer (A5) are shown in Table 1.

[0253] (Example 6) Modified conjugated diene polymer (A6) A modified conjugated diene polymer (A6) was obtained in the same manner as in Example 1, except that n-butyllithium was supplied as a polymerization initiator at a rate of 0.219 mmol / min. The properties of the modified conjugated diene polymer (A6) are shown in Table 1.

[0254] (Example 7) Modified conjugated diene polymer (A7) A modified conjugated diene polymer (A7) was obtained in the same manner as in Example 1, except that tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) was supplied at a rate of 0.007 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) was supplied at a rate of 0.117 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A7) are shown in Table 1.

[0255] (Example 8) Modified conjugated diene polymer (A8) A modified conjugated diene polymer (A8) was obtained in the same manner as in Example 7, except that 1,3-butadiene was supplied at 17.3 g / min, styrene at 6.5 g / min, and an additional butadiene at 5.8 g / min. The properties of the modified conjugated diene polymer (A8) are shown in Table 1.

[0256] (Example 9) Modified conjugated diene polymer (A9) A modified conjugated diene polymer (A9) was obtained in the same manner as in Example 1, except that n-butyllithium was supplied as a polymerization initiator at a rate of 0.224 mmol / min, and tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) at a rate of 0.010 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) at a rate of 0.087 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A9) are shown in Table 1.

[0257] (Example 10) Modified conjugated diene polymer (A10) A modified conjugated diene polymer (A10) was obtained in the same manner as in Example 9, except that tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) was supplied at a rate of 0.009 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) was supplied at a rate of 0.082 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A10) are shown in Table 1.

[0258] (Example 11) Modified conjugated diene polymer (A11) A modified conjugated diene polymer (A11) was obtained in the same manner as in Example 9, except that tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) was supplied at a rate of 0.009 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) was supplied at a rate of 0.080 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A11) are shown in Table 1.

[0259] (Comparative Example 1) Modified conjugated diene polymer (B1) A modified conjugated diene polymer (B1) was obtained in the same manner as in Example 4, except that n-butyllithium was supplied at 0.302 mmol / min as a polymerization initiator, and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) was supplied at 0.150 mmol / min without using tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) as a coupling modifier. The properties of the modified conjugated diene polymer (B1) are shown in Table 1.

[0260] (Comparative Example 2) Modified conjugated diene polymer (B2) A modified conjugated diene polymer (B2) was obtained in the same manner as in Example 2, except that 1,3-butadiene was supplied at 16.1 g / min, styrene at 11.8 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.127 mmol / min, and an additional 1,3-butadiene at 5.4 g / min. The properties of the modified conjugated diene polymer (B2) are shown in Table 1.

[0261] (Comparative Example 3) Modified conjugated diene polymer (B3) A modified conjugated diene polymer (B3) was obtained in the same manner as in Comparative Example 1, except that n-butyllithium was supplied as a polymerization initiator at a rate of 0.234 mmol / min, and tetraalkoxysilane (referred to as "b3" in Table 1) was supplied as a coupling modifier at a rate of 0.075 mmol / min instead of 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1). The physical properties of the modified conjugated diene polymer (B3) are shown in Table 1.

[0262] (Comparative Example 4) Modified conjugated diene polymer (B4) A modified conjugated diene polymer (B4) was obtained in the same manner as in Example 3, except that n-butyllithium was continuously supplied at a rate of 0.265 mmol / min as a polymerization initiator, 2,2-bis(2-oxolanil)propane at a rate of 0.062 mmol / min as a polar compound, trimethoxy(4-vinylphenyl)silane ("a1" in Table 1) at a rate of 0.014 mmol / min as a branching agent, and tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine ("b1" in Table 1) at a rate of 0.012 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine ("b2" in Table 1) at a rate of 0.116 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (B4) are shown in Table 1.

[0263] (Comparative Example 5) Modified conjugated diene polymer (B5) A modified conjugated diene polymer (B5) was obtained in the same manner as in Comparative Example 1, except that n-butyllithium was supplied at a rate of 0.271 mmol / min as a polymerization initiator and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) was supplied at a rate of 0.140 mmol / min as a coupling modifier. The properties of the modified conjugated diene polymer (B5) are shown in Table 1.

[0264] (Comparative Example 6) Modified conjugated diene polymer (B6) A modified conjugated diene polymer (B6) was obtained in the same manner as in Example 3, except that tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) was continuously supplied at a rate of 0.018 mmol / min and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) at a rate of 0.075 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (B6) are shown in Table 1.

[0265] (Comparative Example 7) Modified conjugated diene polymer (B7) A modified conjugated diene polymer (B7) was obtained in the same manner as in Example 1, except that n-butyllithium was continuously supplied at 0.219 mmol / min as a polymerization initiator, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (referred to as "b1" in Table 1) at 0.008 mmol / min, and 1-methyl-4-[3-(trimethoxysilyl)propyl]piperazine (referred to as "b2" in Table 1) at 0.077 mmol / min. The properties of the modified conjugated diene polymer (B7) are shown in Table 1.

[0266] [Table 1]

[0267] (Evaluation of rubber composition) Using the modified conjugated diene polymers A1-A11 and B1-B7 shown in Table 1 as raw materials, rubber compositions were obtained according to the following formulations. • Modified conjugated diene polymer (any of A1-A11 or B1-B7): 70 parts by mass (oil excluded) • Butadiene rubber (product name "BR150" manufactured by Ube Industries): 30 parts by mass • Silica (product name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m²) 2 / g):75.0 parts by mass • Carbon black (product name "Seas KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass • Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass • S-RAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation): 32.0 parts by mass ·Zinc white: 2.5 parts by mass Stearic acid: 2.0 parts by mass • Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 1.7 parts by mass • Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiadylsulfinamide): 1.7 parts by mass • Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass

[0268] Specifically, the above-mentioned materials were kneaded in the following manner to obtain the rubber composition. Using a sealed kneader (capacity 0.5L) equipped with a temperature control device, the first stage of kneading involved a modified conjugated diene polymer (A1-A11 or B1-B7), butadiene rubber, fillers (silica, carbon black), silane coupling agent, S-RAE oil, zinc oxide, and stearic acid, under conditions of a filling rate of 65% and a rotor rotation speed of 30-50 rpm. At this time, the temperature of the sealed kneader was controlled to obtain each rubber composition (compound) so that the discharge temperature was 155-160°C.

[0269] Next, in the second stage of mixing, the compound obtained above was cooled to room temperature, an antioxidant was added, and the mixture was kneaded again under the same conditions as the first stage of mixing to improve the dispersion of silica. In this case as well, the temperature control of the mixer was adjusted so that the discharge temperature of the compound was 155-160°C. After cooling, in the third stage of mixing, sulfur and vulcanization accelerators 1 and 2 were added and kneaded in an open roll set to 70°C. After that, the mixture was molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, the evaluation was performed using the method described below. The results are shown in Table 2.

[0270] (Evaluation 1) Cold flow properties Unvulcanized modified conjugated diene polymers, prepared by the methods shown in the Examples and Comparative Examples, were cut into 3cm × 3cm × 8cm thick sections, and the 3cm × 3cm sections were fixed to a stand tilted at 30°. Cold flow properties were observed after 1 hour at 25°C. The results were evaluated according to the following criteria: Samples that maintained almost their original state were evaluated as having low cold flow properties and excellent mold retention. ◎(Excellent): The sample maintained almost its original shape. ○ (Good): Part of the sample was deformed. × (Poor): The sample was significantly deformed.

[0271] (Evaluation 2) Viscoelastic parameters (fuel efficiency and wet grip) Viscoelastic parameters were measured in torsion mode using the "ARES" viscoelasticity tester manufactured by Rheometrics Scientific. Each measurement value was indexed with the result for the rubber composition of Comparative Example 1 set to 100. Here, tanδ measured at 50°C, frequency of 10Hz, and strain of 3% was used as an indicator of low hysteresis loss, i.e., fuel efficiency, and the result for Comparative Example 1 was standardized to 100. A larger index indicates better fuel efficiency, and values ​​exceeding 65 were evaluated as having excellent fuel efficiency. In addition, tanδ measured at 0°C, frequency of 10Hz, and strain of 1% was used as an indicator of wet grip, and the result for Comparative Example 1 was standardized to 100. A larger index indicates better wet grip, and values ​​exceeding 65 were evaluated as having excellent wet grip.

[0272] (Evaluation 3) Tensile strength and tensile elongation Tensile strength and tensile elongation were measured in accordance with the tensile testing method of JIS K6251. Each measured value was standardized with the result from Example 9 set to 100. Higher values ​​indicate better tensile strength and tensile elongation, and superior fracture characteristics.

[0273] (Evaluation 4) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear after 1000 rotations under a load of 44.4 N was measured in accordance with JIS K6264-2. Each measured value was standardized with the result of Comparative Example 1 set to 100. A higher value indicates better abrasion resistance, and values ​​exceeding 80 were evaluated as having superior abrasion resistance.

[0274] (Rating 5) Average The average values ​​of the indices for fuel efficiency, wet grip, tensile strength, tensile elongation, and wear resistance are listed. A higher number indicates a better balance of these performance characteristics, and a value above 100 is considered superior.

[0275] [Table 2]

[0276] Tables 1 and 2 show that the modified conjugated diene polymer of the present invention exhibits excellent mold retention, and its vulcanized product has an excellent balance of abrasion resistance, fracture properties, and low hysteresis loss properties. [Industrial applicability]

[0277] The modified conjugated diene polymer, the method for producing the modified conjugated diene polymer, and the modified conjugated diene polymer composition and rubber composition of the present invention exhibit excellent moldability and the vulcanized product has an excellent balance of abrasion resistance, fracture properties, and low hysteresis loss properties. Therefore, they can be widely and effectively used in applications such as tires, resin modifiers, automotive interior and exterior parts, vibration-damping rubber, and footwear.

Claims

1. It contains nitrogen atoms and silicon atoms, The Mooney viscosity measured at 100°C is between 100 and 150, the Mooney relaxation rate measured at 100°C is between 0.40 and 0.70, the glass transition temperature Tg is between -90°C and -40°C, and the phase difference index measured at 160°C and 0.1 Hz is between 0.65 and 1.

10. The nitrogen content and silicon content are 50 ppm or more each, based on mass relative to the total amount of the modified conjugated diene polymer. Modified conjugated diene polymers.

2. It has a molecular weight distribution (Mw / Mn) of 1.5 or more and less than 2.

5. The modified conjugated diene polymer according to claim 1.

3. The Mooney viscosity measured at 100°C is between 100 and 130. The modified conjugated diene polymer according to claim 1.

4. The Mooney relaxation rate measured at 100°C is 0.50 or more and 0.70 or less. The modified conjugated diene polymer according to claim 1.

5. The amount of vinyl bonds in the conjugated diene polymer is 15-43%. The modified conjugated diene polymer according to claim 1.

6. A method for producing a modified conjugated diene polymer according to any one of claims 1 to 5, The process involves using an organolithium compound as a polymerization initiator to polymerize at least a conjugated diene compound and an aromatic vinyl compound while reacting them with a coupling modifier to obtain a modified conjugated diene polymer. A method for producing modified conjugated diene polymers.

7. 100 parts by mass of the modified conjugated diene polymer according to any one of claims 1 to 5, A rubber softener of 1.0 part by mass or more and 60 parts by mass or less, Contains Modified conjugated diene polymer composition.

8. A rubber component containing 50 parts by mass or more of the modified conjugated diene polymer described in any one of claims 1 to 5, A filler in an amount of 5.0 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the rubber component, Contains Rubber composition.

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