Modified conjugated diene polymers and methods for manufacturing modified conjugated diene polymers

Abstract

The modified conjugated diene polymer of this invention comprises conjugated diene monomer units and aromatic vinyl monomer units, and has a weight-average molecular weight of 700,000 or more as determined by GPC, with a modification rate of 60% or more. In the tanδ peak diagram corresponding to temperature derived from dynamic viscoelastic analysis using an ARES (Advanced Rheometric Expansion System) based on the following <Condition 1>, it exhibits one tanδ peak in the temperature range of -100℃ to 100℃, and the height of the tanδ peak is 0.90 or more and 1.45 or less. <Condition 1> The tanδ peak diagram was obtained using a dynamic mechanical analyzer in torsion mode at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5℃ / min.

Description

Technical Field

[0001] This invention relates to a modified conjugated diene polymer and a method for manufacturing the modified conjugated diene polymer. Prior Technology

[0002] As basic functions required of automobile tires, they include wet grip and tensile strength. In addition, in recent years, from the perspective of reducing environmental impact, fuel efficiency and wear resistance have also been required.

[0003] As a tire rubber material that meets the requirements for improving the various properties mentioned above, for example, there are rubber compositions that contain conjugated diene rubber-like polymers and reinforcing fillers such as carbon black and silicon dioxide. In this type of rubber composition, the industry has attempted to improve the dispersibility of fillers in the rubber composition and enhance various properties such as abrasion resistance by introducing functional groups with affinity or reactivity to the molecular ends of conjugated diene polymers with higher mobility.

[0004] However, generally speaking, regarding braking performance on wet roads, the required characteristics of tire tread rubber—namely, wet grip—are the opposite of wear resistance. That is, an improvement in one characteristic tends to cause a deterioration in the other. Therefore, tire tread rubber must eliminate this inverse relationship.

[0005] Furthermore, in order to improve the abrasion resistance of rubber compositions, the industry has been actively trying to increase the content of cis-trans conjugated diene polymers in the conjugated diene polymers used in rubber compositions. However, rubber compositions with a higher content of cis-trans conjugated diene polymers have the problem of very poor processability.

[0006] On the other hand, from the perspective of tire durability, excellent tensile properties are also required for the rubber composition. As mentioned above, in order to eliminate the inverse relationship between wet grip and abrasion resistance and improve both properties, when using multiple rubber materials, if the compatibility between these multiple rubber materials is low, there is a tendency for the mechanical strength of the rubber composition to decrease. Therefore, there is a need for a rubber composition that aims to eliminate the inverse relationship between wet grip and abrasion resistance and has excellent mechanical strength.

[0007] For example, Patent Documents 1-3 disclose a rubber composition containing a modified conjugated diene polymer and silicon dioxide, wherein the modified conjugated diene polymer is obtained by reacting an alkoxysilane containing an amino group with the active terminal of the conjugated diene polymer. Patent Document 4 discloses a rubber composition containing a modified conjugated diene polymer with a low vinyl bond content. Furthermore, Patent Document 5 discloses a rubber composition containing a conjugated diene polymer composition incorporating a plurality of modified conjugated diene polymers. [Previous Technical Documents] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2005-290355 [Patent Document 2] Japanese Patent Application Publication No. 11-189616 [Patent Document 3] Japanese Patent Application Publication No. 2003-171418 [Patent Document 4] Japanese Patent No. 6512240 [Patent Document 5] Japanese Patent Application Publication No. 2021-143324 Summary of the Invention

[0009] [The problem the invention aims to solve] However, previously known rubber compositions, represented by the rubber compositions disclosed in Patent Documents 1-4, still have room for improvement in their physical properties. For example, if a rubber composition containing a previously known conjugated diene polymer is to be improved in terms of wet grip, its winter performance will decrease, and its performance on icy and snowy roads will deteriorate, making it difficult to achieve both simultaneously. Furthermore, when such rubber compositions are vulcanized, especially when they are made into vulcanides containing inorganic fillers such as silica, the following problems arise: the dispersibility of silica decreases, the flexibility deteriorates, the performance on ice and snow decreases, and the abrasion resistance is also insufficient.

[0010] Furthermore, a detailed study of the rubber composition described in Patent Document 5 revealed that while it is suitable for designs that prioritize fuel efficiency in tires, as a material for typical summer tires, there is still room for improvement in terms of wet grip and abrasion resistance.

[0011] Therefore, the purpose of this invention is to provide a modified conjugated diene polymer and a method for manufacturing the modified conjugated diene polymer, which can obtain a rubber composition that simultaneously achieves excellent wet grip and abrasion resistance, as well as excellent fuel economy and tensile properties. [Technical means to solve the problem]

[0012] In order to solve the above-mentioned problems, the inventors have conducted intensive research and discovered that a modified conjugated diene polymer can be provided, thereby completing the present invention. The modified conjugated diene polymer has a specified weight average molecular weight and modification rate, and has one peak in the tanδ peak diagram corresponding to temperature derived from dynamic viscoelastic analysis within a specified temperature range. By setting the height of the tanδ peak to a specified numerical range, a rubber composition that simultaneously achieves wet grip performance and abrasion resistance, as well as excellent fuel economy and tensile properties, can be obtained. That is, the present invention is as follows.

[0013] [1] A modified conjugated diene polymer comprising conjugated diene monomer units and aromatic ethylene monomer units, and The weight-average molecular weight, as determined by GPC, is over 700,000. The quality improvement rate is over 60%. In the tanδ peak diagram corresponding to temperature derived from dynamic viscoelastic analysis using ARES (Advanced Rheometric Expansion System) and based on the following <Condition 1>, there is one tanδ peak in the temperature range of -100℃ to 100℃, and The height of the aforementioned tanδ peak is above 0.90 and below 1.45. <Condition 1> The tanδ peak diagram was obtained by using a dynamic mechanical analyzer in torsion mode at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5℃ / min. [2] The modified conjugated diene polymers described in [1] above have a branching degree (Bn) of 7 or higher as measured by the GPC-light scattering method with a viscosity detector. [3] The modified conjugated diene polymers described in [1] or [2] above have a molecular weight distribution of 1.7 or higher and 2.5 or lower. [4] The modified conjugated diene polymers described in any of [1] to [3] above, wherein the estimated glass transition temperature (estimated Tg) of the microstructure in the modified conjugated diene polymer is above -62°C and below -25°C. [5] The modified conjugated diene polymers described in any of [1] to [4] above have two or more polymer segments, and The estimated glass transition temperature (estimated Tg) of the first polymer segment, which constitutes 10% or more of the above-mentioned modified conjugated diene polymer and is the polymer segment closest to the start end, is -90°C or higher and -40°C or lower. The estimated Tg of the second polymer segment, which is closest to the termination of the polymer chain, is above -50°C and below -10°C, and is above the estimated Tg of the first polymer segment. The modifier is bonded to the end of the second polymer chain segment. [6] The modified conjugated diene polymers described in any of [1] to [5] above have modifier residues derived from alkoxysilane compounds having nitrogen atoms. [7] A method for manufacturing a modified conjugated diene polymer, wherein the method is as described in any one of [1] to [6] above, and The polymerization step includes: using a continuous reactor with two or more reactors connected in series, using a lithium compound as a polymerization initiator to polymerize at least one conjugated diene compound. The aforementioned continuous reactor has a monomer addition section, during which at least one conjugated diene compound and an aromatic vinyl compound are added during the polymerization step; and The manufacturing method includes a coupling step: reacting the conjugated diene polymer obtained by the above polymerization step with a modifier having nitrogen atoms. [8] As described above [7] in the method for manufacturing modified conjugated diene polymers, in the polymerization step above, aromatic vinyl compounds are used as polymerization monomers, and The conversion rate of aromatic vinyl compounds in the polymerization intermediates in the above-mentioned monomer addition section is over 70%. [9] The method for manufacturing modified conjugated diene polymers as described in [7] or [8] above, wherein the monomer addition section is located between the piping of the first reactor and the second reactor in the continuous reactor.

[10] The method for manufacturing modified conjugated diene polymers as described in any of [7] to [9] above, wherein a branching agent is added to the monomer addition section. [Effects of the Invention]

[0014] According to the present invention, a modified conjugated diene polymer can be provided, which can obtain a rubber composition that simultaneously achieves excellent wet grip and abrasion resistance, as well as excellent fuel economy and tensile properties. Implementation

[0015] Hereinafter, the form in which the present invention is implemented (hereinafter referred to as "this embodiment") will be described in detail. The following embodiments are illustrative of the invention and are not intended to limit the invention to the following content. The invention may be implemented with appropriate variations within its scope.

[0016] [Modified conjugated diene polymers] The modified conjugated diene polymer of this embodiment contains conjugated diene monomer units and aromatic ethylene monomer units.

[0017] Regarding the modified conjugated diene polymer of this embodiment, the weight-average molecular weight determined by GPC (gel permeation chromatography) is 700,000 or more, the modification rate is 60% or more, and in the tanδ peak diagram corresponding to temperature derived by dynamic viscoelastic analysis using ARES (Advanced Rheometric Expansion System) based on the following <Condition 1>, there is one tanδ peak in the temperature range of -100℃ to 100℃, and the height of the tanδ peak is 1.45 or less and 0.90 or more. <Condition 1> The tanδ peak diagram was obtained by using a dynamic mechanical analyzer in torsion mode at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5℃ / min.

[0018] Based on the above composition, a modified conjugated diene polymer is obtained, which can simultaneously achieve excellent wet grip and abrasion resistance, as well as excellent fuel economy and tensile properties.

[0019] (Conjugated diene compounds) The modified conjugated diene polymer of this embodiment includes conjugated diene monomer units. Examples of conjugated diene compounds that form conjugated diene monomer units include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Of these, 1,3-butadiene and isoprene are preferred from the viewpoint of industrial availability, and 1,3-butadiene is even more preferred. One of these compounds may be used alone, or two or more may be used in combination.

[0020] (Aromatic vinyl compounds) The modified conjugated diene polymer of this embodiment includes aromatic vinyl monomer units. Examples of aromatic vinyl compounds that form aromatic vinyl monomer units include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and stilbene. Of these, styrene or p-methylstyrene is preferred from an industrially readily available perspective, and styrene is even more preferred. One of these compounds may be used alone, or two or more may be used in combination.

[0021] (Unit weight X of bonded aromatic vinyl monomers) In this specification, the amount of bonded aromatic vinyl monomer unit X (mass %) is the mass fraction (mass %) of the bonded aromatic vinyl monomer unit relative to the total mass of the modified conjugated diene polymer or the polymer chain segment described below.

[0022] Here, the amount of bonded aromatic vinyl monomer unit can be calculated by measuring the ultraviolet absorption of the phenyl group in the portion of the modified conjugated diene polymer derived from the aromatic vinyl compound (hereinafter referred to as "bonded aromatic vinyl monomer unit"). Furthermore, the amount of bonded conjugated diene monomer unit can also be determined based on the amount of bonded aromatic vinyl monomer obtained by the above method. Specifically, it can be measured using the method described in the following examples.

[0023] (The amount of vinyl bonds Y in the bonded conjugated diene) The amount of vinyl bonds Y (mol%) in the bonded conjugated diene in this specification is the molar fraction (mol%) of 1,2-bond units relative to the polymeric units derived from the conjugated diene contained in the modified conjugated diene polymer or the polymer segments described below.

[0024] When the modified conjugated diene polymer of this embodiment is a polymer of butadiene and styrene, the amount of vinyl bonds in the bonded conjugated diene can be obtained by determining the amount of vinyl bonds (1,2-bonds) in the bonded butadiene using Hampton's method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, it can be determined by the method described in the following examples.

[0025] (Microstructure) The microstructures described in this specification are compositions of modified conjugated diene polymers or polymers whose polymer chains also include isomers. In the modified conjugated diene polymer of this embodiment, the mass of the copolymer containing styrene and butadiene is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total mass of the modified conjugated diene polymer.

[0026] (Content of bonded aromatic vinyl monomer unit blocks) The modified conjugated diene polymer of this embodiment is preferably one with fewer blocks (hereinafter, sometimes referred to as blocks of aromatic vinyl monomer units) linking four or more aromatic vinyl monomer units, or one without any blocks of aromatic vinyl monomer units. By having fewer or no aromatic vinyl monomer unit blocks, the modified conjugated diene polymer of this embodiment tends to be less likely to exhibit a state with more than two glass transition temperatures (Tg). When the modified conjugated diene polymer is a butadiene-styrene copolymer, the content of bonded aromatic vinyl monomer unit blocks in the modified conjugated diene polymer can be determined by a known method, namely, by decomposing the modified conjugated diene polymer using the method described in Kolthoff's method (IM KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)) and analyzing the amount of polystyrene insoluble in methanol. The content of bonded aromatic vinyl monomer unit blocks, determined by this method, is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0% by mass, relative to the total amount of the modified conjugated diene polymer. Because the modified conjugated diene copolymer and the polymer segments described below do not contain bonded aromatic vinyl monomer unit blocks, the modified conjugated diene polymer tends to exhibit continuous properties in response to temperature changes. Therefore, there is a tendency for sulfides of modified conjugated diene polymers to exhibit continuous changes over a wider temperature range and excellent tensile strength.

[0027] (Method for estimating the glass transition temperature of polymers): Estimated glass transition temperature (estimated Tg) The glass transition temperature of the modified conjugated diene polymer of this embodiment can be estimated using the Gordon Taylor formula (Gordon, M.; Taylor, JSJ Appl. Chem. 1952, 2, 493.), which is extended to two or more compositional systems of the following formula (1). This value is referred to as the estimated glass transition temperature.

[0028] [Number 1]

[0029] In the above formula (1), the subscript i of the variables represents each component of the microstructure contained in the modified conjugated diene polymer, Δαi is the difference in thermal expansion coefficient before and after glass transfer of the homopolymer of component i, wi is the mass ratio of component i in the modified conjugated diene polymer, Tgi is the glass transfer temperature of the homopolymer of component i, and ρi is the density of the homopolymer of component i. Literature values ​​or measured values ​​can be used. For example, when the modified conjugated diene polymer contains styrene, when one of i is set as styrene component, Δαi = 3.6 × 10-4 K-1 can be used according to the thermal expansion coefficient of polystyrene (J. BRANDRUP et al, Polymer Handbook, 3rd edition, (USA), John Wiley & Sons, Inc., 1966, VI-75), Tgi = 105.3℃ can be used according to the measured glass transfer temperature, and ρi = 1.02 g / cm3 can be used according to the measured density.

[0030] As an example, when the modified conjugated diene polymer is a random copolymer of butadiene and styrene, the estimated glass transition temperature (estimated Tg) can be calculated using the amount of the bonded aromatic vinyl monomer unit Xall (mass%), the amount of vinyl bonds in the bonded conjugated diene Yall (mol%), and the coefficients of thermal expansion (Δai), glass transition temperature (Tgi), and density (ρi) of polystyrene (PS) (sometimes represented as St in the following formula), poly-1,2-butadiene (1,2-PBd) (represented as 1,2PBd in the following formula), and poly-1,4-butadiene (1,4-PBd) (represented as 1,4PBd in the following formula), according to the following formula (i).

[0031] [Number 2]

[0032] Since the product of the amount of the bonded aromatic vinyl monomer unit Xall (mass%) and the amount of vinyl bonds in the bonded conjugated diene Yall (mol%) has a very small effect on the denominator of the above equation (i), it can be approximated as the following equation (ii). Furthermore, the following equation (ii) can be approximated as in the following equation (iii).

[0033] [Number 3]

[0034] [Number 4]

[0035] That is, when the modified conjugated diene polymer in this embodiment is a homopolymer of butadiene or a random copolymer of butadiene and styrene, the glass transition temperature (estimated Tg) of the modified conjugated diene polymer can be estimated by formula (iii) above, based on the values ​​usually used for design.

[0036] As described above, the mass ratio of each microstructure component can be determined based on the microstructure of the modified conjugated diene polymer of this embodiment, such as the amount of bonded aromatic vinyl monomer units Xall (mass%) and the amount of vinyl bonds in the bonded conjugated diene Yall (mol%). The glass transition temperature (estimated Tg) of the modified conjugated diene polymer can then be calculated using the above formula (1). That is, the above formula (1) represents the scale of the change in the glass transition temperature of the modified conjugated diene polymer relative to the changes in the amount of bonded aromatic vinyl monomer units Xall (mass%) and the amount of vinyl bonds in the bonded conjugated diene Yall (mol%).

[0037] If the value of the above formula (1) is small, the glass transition temperature (Tg) of the modified conjugated diene polymer of this embodiment will decrease; if the value is large, the glass transition temperature (Tg) will increase. For example, when the above formula (1) is -60°C, the glass transition temperature of the modified conjugated diene polymer is estimated to be -60°C, and when the above formula (1) is -40°C, the glass transition temperature is estimated to be -40°C.

[0038] Thus, the value of Equation (1) obtained from the microstructure of the polymer is usually an indicator of the glass transition temperature of the modified conjugated diene polymer. However, the inventors have found that when the modified conjugated diene polymer near the measured glass transition temperature is moderated over a wider temperature range, the actual viscoelasticity of the sulfide may not be consistent with the viscoelasticity calculated based on the glass transition temperature (estimated Tg) derived from the microstructure and Equation (1). Specifically, when the absolute value of the difference between the estimated glass transition temperatures between the polymer segments is 33°C or more, or the absolute value of the difference in the amount of aromatic vinyl monomer units bonded to each other between the polymer segments is 25% by mass or more, there is a tendency for the glass transition temperature (estimated Tg) predicted by Equation (1) to become significantly inconsistent with the measured glass transition temperature. Therefore, from the perspective of controlling the properties of sulfides affected by glass transition temperature, it has been found that adjusting the estimated glass transition temperature (estimated Tg) calculated based on the microstructure and based on Equation (1) is more effective than adjusting the measured glass transition temperature of modified conjugated diene polymers to a specific value. This is believed to be because DSC (Differential Scanning Calorimetry) captures smaller energy changes, thus raising the overall glass transition temperature at the beginning of the easing of the low Tg portion in the modified conjugated diene polymer, resulting in a measured glass transition temperature lower than the estimated glass transition temperature. For example, experimentally, it has been confirmed that even for modified conjugated diene polymers with identical microstructures throughout, the glass transition temperature measured by DSC can differ by approximately 2-5°C due to differences in the microstructure of each chain segment.

[0039] The lower limit of the estimated Tg value of the modified conjugated diene polymer of this embodiment, derived from the above-mentioned microstructure, is preferably -62°C or higher, more preferably -58°C or higher, and even more preferably -55°C or higher. By estimating that the lower limit of Tg is within the above range, there is a tendency to improve the wet grip and tensile properties of the sulfides of the modified conjugated diene polymers of this embodiment. Furthermore, the upper limit of the estimated Tg value of the modified conjugated diene polymer of this embodiment, derived from the above-mentioned microstructure, is preferably below -25°C, more preferably below -35°C, and even more preferably below -40°C. By using the upper limit of the above formula (1) within the above range, there is a tendency to improve the wear resistance and fuel-saving performance of the sulfide of the modified conjugated diene polymer of this embodiment. The above formula (1) can be controlled within the above numerical range by adjusting the microstructure of the modified conjugated diene polymer. For example, in the case of butadiene-styrene copolymer, the above numerical range can be controlled by adjusting the amount of styrene Xall (mass%) and the amount of vinyl bonds Yaall (mol%) in the butadiene of the modified conjugated diene polymer according to the above formula (iii).

[0040] (polymer chain segment) The modified conjugated diene polymer in this embodiment preferably has two or more polymer segments. A polymer segment refers to a portion of a modified conjugated diene polymer that contains conjugated diene monomer units and aromatic vinyl monomer units, or that contains conjugated diene monomer units. Preferably, the polymer segment contains both conjugated diene monomer units and aromatic vinyl monomer units. Furthermore, in the modified conjugated diene polymer of this embodiment, it is preferable that the polymer chain segments have more than four bonds and that the number of blocks of the aromatic vinyl monomer units is small or non-existent. The modified conjugated diene polymer of this embodiment contains a plurality of polymer segments with distinct microstructures. The amount of aromatic vinyl monomer units or vinyl bonds in the conjugated diene may differ among the polymer segments, and each polymer segment can be distinguished by the methods described in the following examples.

[0041] As described above, the modified conjugated diene polymer of this embodiment preferably has two or more polymer segments. By having two or more polymer segments, a modified conjugated diene polymer undergoes glass transfer in a plurality of temperature ranges.

[0042] The aforementioned polymer segments are manufactured by continuous polymerization and are characterized by having a molecular weight distribution, unlike block structures typically manufactured by batch polymerization. Since a plurality of polymer segments exist in a modified conjugated diene polymer, each with its own molecular weight distribution, the overlapping of these distributions results in each molecule having a different glass transition temperature. That is, depending on the combination of the different molecular weights of its plurality of polymer segments, each molecule behaves as if it has a different glass transition temperature. For example, when a low molecular weight, low glass transition temperature component is bonded to a high molecular weight, high glass transition temperature component, the molecule behaves as a high glass transition temperature component; conversely, when a high molecular weight, low glass transition temperature component is bonded to a low molecular weight, high glass transition temperature component, the molecule behaves as a low glass transition temperature component. Therefore, the modified conjugated diene polymer of this embodiment has a continuous glass transition temperature distribution.

[0043] Equation (1) above can also be applied to polymer segments. By applying the amount of aromatic vinyl monomer units (X1, X2) or the amount of vinyl bonds (Y1, Y2) of each polymer segment, the estimated glass transition temperature (estimated Tg1, estimated Tg2) of each polymer segment can be calculated.

[0044] In this specification, among two or more polymer segments contained in a modified conjugated diene polymer, the polymer segment that accounts for 10% or more of the modified conjugated diene polymer by mass and is closest to the starting end is called the "first polymer segment," and the polymer segment that is closest to the ending end is called the "second polymer segment." The boundary between polymer segments is defined as the point where there is a sharp change in microstructure. In this embodiment, as an example, in the following manufacturing method, the portion polymerized before the addition of a conjugated diene compound, preferably a conjugated diene compound and an aromatic vinyl compound, is defined as the first polymer segment, and the portion polymerized thereafter is defined as the second polymer segment. In addition to the first polymer segment and the second polymer segment, the modified conjugated diene polymer of this embodiment may also contain polymer segments, but from the viewpoint of ease of manufacture, it is preferable to contain two polymer segments. Furthermore, from the viewpoint of balancing wet grip performance and abrasion resistance, in the modified conjugated diene polymer, the ratio of the mass of the first polymer segment to the mass of the second polymer segment relative to the total mass is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0045] In the modified conjugated diene polymer of this embodiment, the lower limit of the estimated glass transition temperature (estimated Tg) of the first polymer segment is preferably -90°C or higher, more preferably -75°C or higher, and even more preferably -65°C or higher. By having the estimated lower limit of Tg of the first polymer segment fall within the above range, there is a tendency to improve the wet grip and tensile properties of the sulfide of the modified conjugated diene polymer of this embodiment. Furthermore, the upper limit of the estimated Tg of the first polymer segment is preferably below -40°C, more preferably below -45°C, and even more preferably below -50°C. By ensuring that the estimated upper limit of the Tg of the first polymer segment is within the above-mentioned range, there is a tendency to improve the wear resistance and fuel-saving performance of the sulfide of the modified conjugated diene polymer of this embodiment. It is assumed that Tg can be controlled within the above-mentioned range by adjusting the microstructure of the modified conjugated diene polymer. For example, in the case of butadiene-styrene polymers, the above-mentioned range can be controlled by adjusting the amount of styrene X1 (mass%) in the first polymer chain segment and the amount of vinyl bonds Y1 (mol%) in the butadiene using the above formula (iii).

[0046] In the modified conjugated diene polymer of this embodiment, the estimated lower limit of Tg for the second polymer segment is preferably -50°C or higher, more preferably -45°C or higher, and even more preferably -35°C or higher. By having the estimated lower limit of Tg of the second polymer segment fall within the above range, there is a tendency to improve the wet grip and tensile properties of the sulfide of the modified conjugated diene polymer of this embodiment. Furthermore, the upper limit of the estimated Tg of the second polymer segment is preferably below -10°C, more preferably below -15°C, and even more preferably below -20°C. Furthermore, it is preferable that the estimated Tg of the second polymer segment is greater than or equal to the estimated Tg of the first polymer segment. Furthermore, it is preferable that the modifier is bonded to the end of the second polymer chain segment. By estimating that the upper limit of Tg is within the above range, the wear resistance and fuel-saving performance of the modified conjugated diene polymer sulfide of this embodiment can be improved. It is assumed that Tg can be controlled within the above-mentioned range by adjusting the microstructure of the modified conjugated diene polymer. For example, in the case of butadiene-styrene polymers, the above-mentioned range can be controlled by adjusting the amount of styrene X2 (mass%) in the second polymer and the amount of vinyl bonds Y2 (mol%) in the butadiene using formula (iii).

[0047] By precisely controlling the ratio of the average molecular weight of the first polymer segment and the second polymer segment, and the difference in their estimated glass transition temperatures, the height of the tanδ peak of the following modified conjugated diene polymers can be controlled within a specified range. This results in modified conjugated diene polymers that exhibit a balance between suppressing the reduction in tensile strength and possessing excellent wet grip and abrasion resistance.

[0048] The greater the difference in estimated glass transition temperature (|estimated Tg2 - estimated Tg1|) between the first and second polymer segments, the slower the glass transition occurs over a wider temperature range. Therefore, there is a tendency for the height of the tanδ peak of the modified conjugated diene polymer to decrease.

[0049] Polymer segments can also be defined in previously known continuously polymerized conjugated diene polymers, but the glass transition temperature is presumed to vary less and exhibit abrupt glass transition behavior over a narrow temperature range. On the other hand, in the modified conjugated diene polymer of this embodiment, the plurality of polymer segments have different glass transition temperatures, and as described above, glass transition occurs slowly over a wider temperature range. Therefore, the tendency for the height of the tanδ peak of the modified conjugated diene polymer to decrease becomes more significant, thus aiming to simultaneously achieve wet grip performance and abrasion resistance.

[0050] In the modified conjugated diene polymer of this embodiment, the lower limit of the estimated glass transition temperature difference between the first polymer segment and the second polymer segment is preferably 18°C ​​or more, more preferably 25°C or more, and even more preferably 30°C or more. The upper limit of the estimated glass transition temperature difference between the first polymer segment and the second polymer segment is preferably 60°C or less, more preferably 50°C or less, and even more preferably 40°C or less.

[0051] (Polymer segment ratio) The closer the ratio of the average molecular weight of the first polymer segment to the second polymer segment is to 1, the slower the glass transfer tends to occur over a wider temperature range. Therefore, there is a tendency for the height of the tanδ peak, which is correlated with the amount of local glass transfer within a narrow temperature range, to decrease.

[0052] In the modified conjugated diene polymer of this embodiment, it is preferable that the first and second polymer segments have a specified mass ratio. The polymer segment mass ratio represents the average mass fraction of each polymer segment relative to the whole modified conjugated diene polymer. In this embodiment, the mass ratio of the first and second polymer segments of the modified conjugated diene polymer is defined as the mass ratio of the polymer segments obtained in each of steps P1 and P2, which are the polymerization steps of the following polymer segments, to the total mass of the modified conjugated diene polymer. Furthermore, the ratio of the mass ratio of the first polymer segment (r1) to the mass ratio of the second polymer segment (r2) (R = r1 / r2, hereinafter sometimes referred to as the ratio of the mass ratios of polymer segments) is preferably 0.25 to 4, more preferably 0.33 to 3, and even more preferably 0.4 to 2.4. If the lower limit of R is 0.25 or higher, there is a tendency for the sulfide to have excellent fuel-saving performance. Furthermore, if the upper limit of R is 4 or lower, there is a tendency for the sulfide to have excellent processability. The mass ratio R of the above polymer segments can be determined by the method described in the following examples. It can be controlled within the above-mentioned value range by adjusting the polymerization time, polymerization temperature, monomer addition amount, vinyl bond amount and other conditions in the polymerization step of each polymer segment in the manufacturing step of the modified conjugated diene polymer in this embodiment.

[0053] The method for introducing multiple polymer segments into the molecule of a modified conjugated diene polymer is carried out by the following method: using a continuous reactor with multiple reactors connected in series as described below, a conjugated diene compound, an aromatic vinyl compound, a polar substance, and a solvent are sequentially added to each reactor by continuous solution polymerization. The substances added sequentially may be the same or different between the reactors.

[0054] (tanδ crest height) Regarding the modified conjugated diene polymer of this embodiment, in the tanδ peak diagram corresponding to temperature derived from dynamic viscoelastic analysis performed using ARES (Advanced Rheometric Expansion System) based on the above <Condition 1>, there is one tanδ peak in the temperature range of -100℃ to 100℃, and the height of the tanδ peak is 0.90 or more and 1.45 or less, preferably 0.90 or more and 1.25 or less, and even more preferably 0.90 or more and 1.15 or less. If the height of the tanδ peak is within the above range, it has the ability to suppress the reduction of intramolecular compatibility of the modified conjugated diene polymer, and has polymer segments with high concentrations of aromatic vinyl monomer units and high concentrations of conjugated diene monomer units that form vinyl bonds, and excellent wet grip properties. Therefore, it tends to obtain a sulfide that suppresses the reduction of tensile strength and has a good balance between excellent wet grip properties and abrasion resistance.

[0055] In this specification, the "tanδ peak" refers to the peak appearing in the tanδ peak diagram corresponding to the temperature derived from dynamic viscoelastic analysis when the modified conjugated diene polymer is measured using a dynamic mechanical analyzer (TA Instruments, ARES-G2) in torsion mode at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5 °C / min. The "height of the tanδ peak" is defined as the tanδ value at its apex.

[0056] In typical random copolymer manufacturing methods, from the perspective of production stability or cost, it is rare to intentionally and drastically change polymerization conditions such as polymerization temperature or monomer and catalyst concentrations during polymerization. Therefore, the tanδ peak of such random copolymers becomes higher and sharper. This is because, in most cases, aromatic ethylene monomer units have high randomness and always have a uniform microstructure. Such random copolymers exhibit a significant inverse relationship between wet grip and abrasion resistance.

[0057] On the other hand, in the case of block copolymers manufactured by batch polymerization, the tanδ peak is significantly broadened, with a decrease in tanδ peak height, or a tendency for the tanδ peak to split into two or more. This is because continuous blocks of aromatic vinyl monomer units are formed within the conjugated diene polymer, or the aromatic vinyl monomer units are too densely distributed on one side of the block copolymer chain, reducing randomness and causing phase separation. This results in a tendency for poor tensile strength when producing sulfides.

[0058] The height of the tanδ peak indicates the degree of randomness in the microstructure of the molecule. By using the above-mentioned tanδ peak height of 0.90 and below 1.45, the modified conjugated diene polymer has the ability to suppress the reduction of intramolecular compatibility and has a high concentration of aromatic vinyl monomer units and a high concentration of conjugated diene monomer units that form vinyl bonds, as well as polymer segments with excellent wet grip properties. Thus, the following modified conjugated diene polymer can be obtained, which can suppress the reduction of tensile strength and has a balance between excellent wet grip properties and abrasion resistance.

[0059] In order to control the height of the tanδ peak of the modified conjugated diene polymer of this embodiment to be above 0.90 and below 1.45, it is effective to control the microstructure of the two polymer segments. Specifically, by increasing the difference in estimated Tg between the two polymer segments and making the ratio of their average molecular weights close to 1, the height of the tanδ peak can be reduced. Conversely, by increasing the difference in estimated Tg and making the ratio of their average molecular weights far from 1, the height of the tanδ peak can be increased. As a method to control the difference in estimated Tg between two polymer segments, one approach is to polymerize aromatic vinyl monomer units and conjugated diene monomer units that form vinyl bonds in a moderately random distribution. Specifically, this can be controlled by adding a conjugated diene compound and an aromatic vinyl compound between the polymerization steps of the first and second polymer segments, and by adjusting the amount of aromatic vinyl monomer units, the amount of polar substances added, and the polymerization temperature in the polymerization steps of the first and second polymer segments. Furthermore, the ratio of the average molecular weights of the two polymer segments can be controlled by adjusting the polymerization time, polymerization temperature, monomer addition amount, and polar substance addition amount in the polymerization steps of each polymer segment.

[0060] In continuous polymerization, to control the tanδ peak height within a specified range and to maintain a moderate degree of randomness in the aromatic vinyl monomer units and the vinyl-bonded conjugated diene monomer units, it is effective to use two or more reactors with different polymerization conditions to polymerize sequentially. Specifically, to maintain the specified estimated glass transition temperature, the amount of aromatic vinyl monomers added must be kept relatively high throughout the polymerization process, and the amount of bonded aromatic vinyls in the first polymer segment and the amount of vinyl bonds in the bonded conjugated diene must be reduced. Here, when the amount of polar substances or polymerization conditions such as polymerization temperature and polymerization concentration are set lower in order to reduce the amount of bonded aromatic vinyls in the first polymer segment and the amount of vinyl bonds in the bonded conjugated diene, the conversion rate of the aromatic vinyl compound will be significantly reduced. When the conversion rate of aromatic vinyl compounds is insufficient, the concentration of aromatic vinyl compounds in the system will increase during the period until the polymerization of the second polymer segment, forming aromatic vinyl monomer blocks, and there is a tendency to make it impossible to control the tanδ peak height within the specified range. Therefore, in order to control the tanδ peak height within the specified range, a preferred approach is that the conversion rate of aromatic vinyl compounds in the discharge section of the first polymer segment polymerization step is 70% or more, and the remaining conjugated diene compound and aromatic vinyl compounds are added immediately before the polymerization of the second polymer segment. Furthermore, as described below, the conversion rate of aromatic vinyl compounds is defined as the mass of aromatic vinyl compounds consumed in the polymerization reaction to form conjugated diene polymers relative to the total amount of aromatic vinyl compounds added during the measurement.

[0061] (Glass transfer temperature) The measured glass transition temperature (Tg) of the modified conjugated diene polymer of this embodiment is preferably -62°C or higher, more preferably -58°C or higher, and even more preferably -55°C or higher. Furthermore, the measured glass transition temperature of the modified conjugated diene polymer of this embodiment is preferably below -25°C, more preferably below -35°C, and even more preferably below -40°C. If the glass transition temperature meets the above range, the fuel-saving performance of the sulfide of the modified conjugated diene polymer of this embodiment tends to become more excellent. Furthermore, the modified conjugated diene polymer of this embodiment is preferably within the range of estimated Tg calculated based on the microstructure, which is above -62°C and below -25°C. The modified conjugated diene polymer of this embodiment that satisfies this range has a measured glass transition temperature within the above-mentioned range. The glass transition temperature can fall within any combination of the aforementioned upper and lower limits. The glass transition temperature of the modified conjugated diene polymer can be determined according to ISO 22768:2006. More specifically, regarding the glass transition temperature, differential scanning calorimetry (DSC) is performed while heating within a specified temperature range, thereby recording the DSC curve, and the inflection point of the DSC curve is set as the glass transition temperature. Specifically, it can be determined by the method described in the examples below. Furthermore, the modified conjugated diene polymer of this embodiment may contain plasticizing components such as the resin or processing oil described below, but these components must be removed when determining the Tg of the modified conjugated diene copolymer of this embodiment by DSC measurement.

[0062] The measured glass transition temperature of modified conjugated diene polymers varies depending on the amount of bonded aromatic vinyl monomer units and the amount of vinyl bonds in the bonded conjugated diene. Specifically, increasing the amount of bonded aromatic vinyl monomer units and the amount of vinyl bonds in the bonded conjugated diene increases the glass transition temperature, while decreasing the amount of bonded aromatic vinyl monomer units and the amount of vinyl bonds in the bonded conjugated diene decreases the glass transition temperature.

[0063] (weight average molecular weight) The weight-average molecular weight (Mw) of the modified conjugated diene polymer of this embodiment, as determined by GPC, is 70 × 10⁴ or higher, preferably 75 × 10⁴ or higher, more preferably 80 × 10⁴ or higher, and even more preferably 85 × 10⁴ or higher. If the weight-average molecular weight determined by GPC meets the above range, the sulfide tends to have excellent abrasion resistance. Furthermore, the weight-average molecular weight is preferably 150 × 10⁴ or less, more preferably 110 × 10⁴ or less, and even more preferably 100 × 10⁴ or less. If the weight-average molecular weight meets the above range, the dispersibility of the filler in the sulfide is better, and it tends to have better processability. The weight-average molecular weight can fall within any combination of the above upper and lower limits. The weight average molecular weight of the modified conjugated diene polymer can be determined by GPC assay, specifically by the method described in the examples below.

[0064] (Number average molecular weight) The number average molecular weight of the modified conjugated diene polymer of this embodiment, as determined by GPC, is preferably 25 × 10⁴ or higher, more preferably 30 × 10⁴ or higher, and even more preferably 35 × 10⁴ or higher. If the number average molecular weight determined by GPC meets the above range, the sulfide tends to have excellent abrasion resistance. Furthermore, the aforementioned number average molecular weight is preferably 80 × 10⁴ or less, more preferably 70 × 10⁴ or less, and even more preferably 50 × 10⁴ or less. If the aforementioned number average molecular weight meets the above range, the dispersibility of the filler in the sulfide is more excellent, and it tends to have excellent processability. The number average molecular weight can fall within any combination of the aforementioned upper and lower limits. The number average molecular weight of the modified conjugated diene polymer can be determined by GPC assay, using the method described in the examples below.

[0065] The weight-average molecular weight and number-average molecular weight of modified conjugated diene polymers can be controlled within the above-mentioned range by adjusting the ratio of the amount of polymerization initiator to the amount of monomer, the type and amount of branching agent, the type and amount of coupling agent, the shape of the polymerization reactor, the stirring intensity, and the residence time of the polymer solution.

[0066] (Molecular weight distribution) The molecular weight distribution of the modified conjugated diene polymer in this embodiment is expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn). The molecular weight distribution of the modified conjugated diene polymer in this embodiment is preferably 1.7 or higher. Modified conjugated diene polymers with molecular weight distributions within this range tend to have better processability when formulated into sulfides. The molecular weight distribution of the modified conjugated diene polymer in this embodiment is preferably 1.8 or higher, and more preferably 2.0 or higher. Furthermore, as an upper limit, it is preferably below 2.5, more preferably below 2.2, and even more preferably below 2.1. The molecular weight distribution can fall within any combination of the aforementioned upper and lower limits.

[0067] (Munich viscosity) The Munich viscosity of the modified conjugated diene polymer of this embodiment, measured at 100°C, is preferably 50 or higher and 180 or lower, more preferably 70 or higher and 160 or lower, and even more preferably 90 or higher and 140 or lower. The modified conjugated diene polymer of this embodiment has a Munich viscosity within the above-mentioned range, and tends to have further improved processability during vulcanization and abrasion resistance of its sulfides. The Munich viscosity of the modified conjugated diene polymer can be determined by the method described in the following examples. The Munich viscosity of the modified conjugated diene polymer in this embodiment can be controlled within the above-mentioned range by adjusting the amount of polymerization initiator, the type and amount of branching agent, the type and amount of modifier, and the type and amount of plasticizer.

[0068] (Branching degree (Bn)) From the viewpoints of fuel efficiency, processability, wear resistance, and tensile properties, the branching degree (Bn) of the modified conjugated diene polymer of this embodiment, as measured by the GPC-light scattering method with a viscosity detector (hereinafter also referred to as branching degree (Bn)), is preferably 7 or higher. Typically, branching degree (Bn) is an indicator of the branched structure of a polymer. A branching degree (Bn) of 7 or higher means that in the modified conjugated diene polymer of this embodiment, there are actually 5 or more side chains relative to the longest polymer backbone.

[0069] Here, "branching" refers to the formation of a polymer chain through bonding between two polymer chains. Furthermore, "branching degree (Bn)" is the number of polymer chains directly or indirectly bonded to each other relative to the longest polymer backbone. That is, it considers not only the side chains bonded to the longest polymer chain, but also the number of branches of those side chains when they branch further. Therefore, when one polymer chain acts as a side chain bonded to the longest polymer chain, and another polymer chain is then bonded to that side chain, the branching degree is 2.

[0070] The branching degree (Bn) of the modified conjugated diene polymer was determined by the shrinkage factor (g') using the GPC-light scattering method with an adhesion detector, and was defined as g' = 6Bn / {(Bn+1)(Bn+2)}.

[0071] Generally, when compared to a linear polymer with the same absolute molecular weight, branched polymers tend to have smaller molecular sizes. Here, "molecular size" refers to the actual volume occupied by the molecule. The shrinkage factor (g') is a relative indicator of the molecular size of the target polymer; it is an index of the ratio of the molecular size of the target polymer to the molecular size of a linear polymer with the same absolute molecular weight. That is, if the polymer has a higher degree of branching, its size is relatively smaller, and therefore the shrinkage factor (g') tends to decrease.

[0072] Here, it is known that there is a correlation between the molecular size and intrinsic viscosity of a polymer. Therefore, in this embodiment, the shrinkage factor (g') is defined as the ratio of intrinsic viscosity. That is, the shrinkage factor (g') is defined as the ratio of the intrinsic viscosity [η] of the target polymer to the intrinsic viscosity [η0] of a linear polymer having the same absolute molecular weight as the target polymer ([η] / [η0]).

[0073] Furthermore, the intrinsic viscosity [η0] of linear polymers is known to be based on the formula [η0] = 10⁻³.498M⁰.711. In this formula, M is the absolute molecular weight determined by the light scattering method described in the examples below. Therefore, by determining the absolute molecular weight and intrinsic viscosity of the target polymer using the GPC-light scattering method with a viscosity detector, the shrinkage factor (g') and branching degree (Bn) can be calculated. The calculated branching degree (Bn) accurately represents the number of polymer chains directly or indirectly bonded to each other on the longest polymer backbone.

[0074] The calculated branching degree (Bn) is an indicator of the branched structure of modified conjugated diene polymers. For example, in the case of a typical 4-branched star polymer (4 polymer chains connected to the central part), the arms of 2 polymer chains are bonded to the longest highly branched backbone structure, and the branching degree (Bn) is evaluated as 2. In the case of a typical 8-branched star polymer, the arms of the 6 polymer chains are bonded to the longest highly branched main chain structure, and the branching degree (Bn) is evaluated as 6. The modified conjugated diene polymer of this embodiment is preferably branched (Bn) of 7 or more. However, in this case, it means a modified conjugated diene polymer that has the same branches as a star polymer structure with 9 branches.

[0075] Here, "branching" refers to the formation of a polymer by bonding directly or indirectly with other polymers. Furthermore, "branching degree (Bn)" is the number of polymers that are directly or indirectly bonded to each other in the longest main chain structure.

[0076] With a branching degree (Bn) of 7 or higher, the modified conjugated diene polymer of this embodiment exhibits excellent processability when made into sulfides, and also demonstrates excellent fuel economy and wear resistance when made into sulfides. Generally, as the absolute molecular weight increases, processability tends to deteriorate. However, by achieving a branching degree (Bn) of 7 or higher, the viscosity increase associated with the formation of sulfides due to the increase in absolute molecular weight is significantly suppressed. Therefore, thorough mixing with silica, for example, during the compounding process, allows silica to disperse around the modified conjugated diene polymer. As a result, for example, in modified conjugated diene polymers, by setting a larger molecular weight, abrasion resistance and breaking strength can be improved. Furthermore, through thorough compounding, silica can be dispersed around the polymer, allowing functional groups to function and / or react, thereby achieving practically sufficient fuel efficiency and wet grip.

[0077] Furthermore, in the modified conjugated diene polymer of this embodiment, in the tanδ peak height of the temperature-corresponding tanδ peak diagram derived from the dynamic viscoelastic analysis based on the above <Condition 1>, which is in the range of 0.90 or higher and 1.45 or lower, the branching degree (Bn) is 7 or higher, thereby the sulfide has better fuel-saving performance and wet grip performance.

[0078] The branching degree (Bn) of the modified conjugated diene polymer in this embodiment is preferably 7 or more, more preferably 8 or more, and even more preferably 10 or more. Modified conjugated diene polymers with a branching degree (Bn) within this range tend to have excellent processability when made into sulfides.

[0079] Furthermore, the upper limit of the branching degree (Bn) of the modified conjugated diene polymer in this embodiment is not particularly limited. It can be above the detection limit, but preferably below 84, more preferably below 80, further preferably below 57, and even more preferably below 20. The modified conjugated diene polymer of this embodiment has a branching degree (Bn) of 84 or less, and tends to have excellent wear resistance and tensile properties when it is made into a sulfide.

[0080] The branching degree (Bn) of the modified conjugated diene polymer can be controlled to be 7 or higher by combining the amounts of the branching agent and the terminal coupling agent described below. Specifically, the branching degree can be controlled by adjusting the functional group of the branching agent, the amount of the branching agent added, the timing of the addition of the branching agent, and the functional group and amount of the coupling agent or nitrogen-containing modifier. More specifically, by using the method described in the manufacturing method of the modified conjugated diene polymer described below, the branching degree can be controlled to be 7 or higher.

[0081] (Main chain branch structure) In order to control the degree of branching, the modified conjugated diene polymer of this embodiment preferably has a main chain branching structure. Regarding the main chain branching structure, when the modified conjugated diene polymer of this embodiment has a portion derived from a vinyl monomer containing alkoxysilyl or halosilyl groups, the number of branching points in that portion is preferably two or more, more preferably three or more, and even more preferably four or more.

[0082] Furthermore, the branching points that form the main chain branching structure preferably have at least two polymer chains, more preferably three or more non-main chain polymer chains, and even more preferably four or more non-main chain polymer chains.

[0083] In particular, in the main chain branched structure containing vinyl monomers with alkoxysilyl or halosilyl groups, when the signal is detected by 29Si-NMR, the peak originating from the main chain branched structure is detected in the range of -45 ppm to -65 ppm, and further in the range of -50 ppm to -60 ppm.

[0084] (Star-shaped polymer structure) The modified conjugated diene polymer of this embodiment preferably has a star-shaped polymer structure, and the branches derived from the star-shaped polymer structure preferably have 3 or more branches, more preferably 4 or more branches, more preferably 6 or more branches, and more preferably 8 or more branches.

[0085] The modified conjugated diene polymer of this embodiment is preferably a modified conjugated diene polymer having a star-shaped polymer structure with three or more branches, and preferably, at least one branch of the star structure has a portion derived from a vinyl monomer containing alkoxysilyl or halosilyl groups, and the portion derived from the vinyl monomer containing alkoxysilyl or halosilyl groups further has a main chain branch structure. Regarding the method for obtaining the modified conjugated diene polymer with this structure, the above-mentioned "star-shaped polymer structure" can be formed by adjusting the functional group of the coupling agent and the amount of coupling agent added, and the "main chain branch structure" can be controlled by adjusting the functional group of the branching agent, the amount of branching agent added, and the timing of adding the branching agent.

[0086] To obtain modified conjugated diene polymers, for example, the following methods can be used: polymerization is carried out using an organolithium compound as a polymerization initiator, a branching agent that imparts specific branching points is added during or after polymerization, and a coupling agent that imparts specific branching rates is used for modification after further polymerization. The modified conjugated diene polymer has a star-shaped polymer structure with three or more branches, and at least one branch of the star structure has a portion derived from a vinyl monomer containing alkoxysilyl or halosilyl groups, and the portion derived from the vinyl monomer containing alkoxysilyl or halosilyl groups further has a main chain branching structure. The method for controlling such polymerization conditions is described in the manufacturing method shown in the following examples.

[0087] (Detailed structure of the main chain branch structure) In the modified conjugated diene polymer of this embodiment, the portion derived from the vinyl monomer containing alkoxysilyl or halosilyl is based on the monomer unit of the compound represented by the following general formula (1) or (2), and preferably has a branch point of polymer chain due to the monomer unit of the compound represented by the following formula (1) or (2), more preferably is a modified conjugated diene polymer obtained by using a coupling agent, and even more preferably is a modified conjugated diene polymer modified by a nitrogen-containing group at at least one end of the modified conjugated diene polymer. Furthermore, coupling agents can also perform the functions of the following modifiers.

[0088] [Chemistry 1]

[0089] [Chemistry 2]

[0090] In formula (1), R1 represents a hydrogen atom or an alkyl group with 1 to 20 carbon atoms or an aryl group with 6 to 20 carbon atoms, which may partially have a branched structure. R2 to R3 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may partially have a branched structure. When there are multiple R1 to R3, R1 to R3 are independent. X1 represents an independent halogen atom. m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. In formula (2), R2 to R5 independently represent alkyl groups with 1 to 20 carbon atoms or aryl groups with 6 to 20 carbon atoms, which may partially have a branched structure. When there are multiple R2~R5, each R2~R5 is independent. X2~X3 represent independent halogen atoms. m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3.

[0091] The modified conjugated diene polymer of this embodiment is preferably a monomer unit having a compound represented by the above formula (1), wherein R1 is a hydrogen atom and m=0 in the above formula (1). This increases the number of branches, which tends to improve wear resistance and processability.

[0092] Furthermore, the modified conjugated diene polymer of this embodiment is preferably a monomer unit having a compound represented by the above formula (2), wherein in the above formula (2), m=0 and b=0. This tends to improve wear resistance and processability.

[0093] Furthermore, the modified conjugated diene polymer of this embodiment is preferably a monomer unit having a compound represented by the above formula (2), wherein in the above formula (2), m=0, l=0, n=3, a=0, b=0, and c=3. This tends to improve wear resistance and processability.

[0094] Furthermore, the modified conjugated diene polymer of this embodiment is preferably a modified conjugated diene polymer having monomer units based on the compound represented by formula (1) above, wherein in formula (1) above, R1 is a hydrogen atom, m=0, l=0, n=3. This results in an increased modification rate and branching degree, tending to improve fuel efficiency, wear resistance, and processability.

[0095] (branching agent) When constructing the main chain branched structure, the modified conjugated diene polymer of this embodiment is preferably a branching agent having the structure represented by the following formula (1) or formula (2) as the branching agent.

[0096] [Chemistry 3]

[0097] [Chemistry 4]

[0098] In formula (1), R1 represents a hydrogen atom or an alkyl group with 1 to 20 carbon atoms or an aryl group with 6 to 20 carbon atoms, which may partially have a branched structure. R2 to R3 represent alkyl groups with 1 to 20 carbon atoms or aryl groups with 6 to 20 carbon atoms, and may partially have a branched structure. When there are a complex number of R1~R3, R1~R3 ​​are independent. X1 represents an independent halogen atom. m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. In formula (2), R2 to R5 independently represent alkyl groups with 1 to 20 carbon atoms or aryl groups with 6 to 20 carbon atoms, which may partially have a branched structure. When there are multiple R2~R5, each R2~R5 is independent. X2~X3 represent independent halogen atoms. m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3.

[0099] From the perspective of the continuity of polymerization and the improvement of branching degree, the branching agent used in constructing the main chain branching structure of the modified conjugated diene polymer of this embodiment is preferably a compound in formula (1) above where R1 is a hydrogen atom and m=0.

[0100] Furthermore, from the viewpoint of increasing the degree of branching, the branching agent used in constructing the main chain branching structure of the modified conjugated diene polymer of this embodiment is preferably a compound in the above formula (2) in which m=0 and b=0.

[0101] Furthermore, from the viewpoint of the continuity of polymerization and the improvement of modification rate and branching degree, the branching agent used in constructing the main chain branching structure of the modified conjugated diene polymer of this embodiment is preferably a compound in the above formula (1) where R1 is a hydrogen atom, m=0, l=0, and n=3.

[0102] Furthermore, from the viewpoint of improving the modification rate and branching degree, the branching agent used in constructing the main chain branching structure of the modified conjugated diene polymer of this embodiment is preferably a compound in the above formula (2) with m=0, l=0, n=3, a=0, b=0, c=3.

[0103] Examples of branching agents represented by formula (1) above 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, tributoxy(3-vinylphenyl)silane, and triisopropoxy(3-vinylphenyl)silane. Alkane, trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, tripropoxy(2-vinylphenyl)silane, tributoxy(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, etc., but not limited to the above.

[0104] For example, examples include: 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, etc.

[0105] Furthermore, examples include: 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, tributoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl)silane, and triethoxy(2-isopropenylphenyl)silane. )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(4 ... oxymethyl (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, dimethyl... Dimethyl isopropoxy(4-isopropylphenyl)silane, dimethylmethoxy(3-isopropylphenyl)silane, dimethylethoxy(3-isopropylphenyl)silane, dimethylpropoxy(3-isopropylphenyl)silane, dimethylbutoxy(3-isopropylphenyl)silane, dimethylisopropoxy(3-isopropylphenyl)silane, dimethylmethoxy(2-isopropylphenyl)silane, dimethylethoxy(2-isopropylphenyl)silane, dimethylpropoxy(2-isopropylphenyl)silane, dimethylbutoxy(2-isopropylphenyl)silane, dimethylisopropoxy(2-isopropylphenyl)silane, etc.

[0106] Furthermore, examples include: trichloro(4-vinylphenyl)silane, trichloro(3-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, and so on. Bromomethyl(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, dimethylbromo(2-vinylphenyl)silane, etc.

[0107] 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, trichloro(4-vinylphenyl)silane are preferred, and more preferably trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane.

[0108] Examples of branching agents represented by formula (2) above include: 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)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-tripropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)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-tripropoxysilylphenyl)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, 1,1-bis(4-(diethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylethoxysilyl)phenyl)ethylene, etc., but not limited to the above.

[0109] 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, and 1,1-bis(4-trimethoxysilylphenyl)ethylene is even more preferred.

[0110] (Modification rate) The modified conjugated diene polymer in this embodiment has a modification rate of 60% or more. In this specification, "modification rate" is expressed as a percentage (%). It refers to the mass percentage of modified conjugated diene polymers containing specific functional groups that have affinity or bonding reactivity with fillers, relative to the total amount of the mixture, obtained by modifying conjugated diene polymers with nitrogen-containing modifiers. Therefore, when the specific functional group contains nitrogen atoms, it represents the mass ratio of nitrogen-containing modified conjugated diene polymers to the total amount of the mixture. In this specification, "modified conjugated diene polymer" means modified conjugated diene polymer, and a mixture of modified conjugated diene polymer and unmodified conjugated diene polymer. For example, when obtaining a conjugated diene polymer that includes a modified conjugated diene polymer obtained by modifying it through a terminal reaction of a nitrogen-atom modifier with a conjugated diene polymer, the mass ratio of the modified conjugated diene polymer with nitrogen-containing functional groups produced by the nitrogen-atom modifier to the total amount of the modified conjugated diene polymer is the modification rate.

[0111] In this embodiment, the modified conjugated diene polymer is preferably modified at the end of the second polymer segment. By bonding the filler to the end of the second polymer segment, which has a higher glass transition temperature, there is a tendency to obtain sulfides with better wet grip properties.

[0112] The modification rate can be determined by using a chromatography method that can separate the modified components containing functional groups from the unmodified components. As an example of the method using chromatography, the following method can be used: a gel permeation chromatography column with polar substances such as silicon dioxide that adsorb specific functional groups as the packing material is used, and an internal standard for non-adsorbed components is used for comparison, thereby performing quantification. More specifically, the modification rate can be obtained by the following method: for a sample solution containing the sample and a low molecular weight internal standard polystyrene, the amount of adsorption onto the silicon dioxide column is determined by the difference between the chromatogram obtained using a polystyrene-based gel column and the chromatogram obtained using a silicon dioxide-based column. More specifically, the modification rate can be determined by the method described in the following examples.

[0113] In the modified conjugated diene polymer of this embodiment, the modification rate can be controlled by adjusting the amount of modifier added and the reaction method. For example, the above-mentioned modification rate can be achieved by combining the following methods: using an organolithium compound having at least one nitrogen atom in its molecule as a polymerization initiator, copolymerizing a monomer having at least one nitrogen atom in its molecule, and using a modifier with the following structural formula, and controlling the polymerization conditions.

[0114] From the viewpoint of fuel-saving performance of sulfides, the modification rate of the modified conjugated diene polymer in this embodiment is 60% or more, preferably 65% ​​or more, and more preferably 70% or more.

[0115] <Modifiers containing nitrogen atoms> Examples of nitrogen-containing modifiers include: amine compounds without active hydrogen, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds with nitrogen atoms, vinyl compounds with nitrogen atoms, epoxy compounds with nitrogen atoms, and alkoxysilane compounds with nitrogen atoms, but are not limited to the above.

[0116] As a modifier containing nitrogen atoms, it is preferable to be an amine compound that does not contain active hydrogen, such as: tertiary amine compounds, protected amine compounds formed by replacing the above-mentioned active hydrogen with a protecting group, imine compounds represented by the general formula -N=C, and the above-mentioned alkoxysilane compounds containing nitrogen atoms.

[0117] Examples of isocyanate compounds that serve as nitrogen-containing modifiers include: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3,5-phenyltriisocyanate, etc., but are not limited to the above.

[0118] Examples of isocyanuric acid derivatives that serve as nitrogen-containing modifiers include: 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl) isocyanurate, 1,3,5-tris(ethyleneoxy-2-yl)-1,3,5-triazacyclohexane-2,4,6-trione, 1,3,5-tris(isocyanomethyl)-1,3,5-triazacyclohexane-2,4,6-trione, 1,3,5-trivinyl-1,3,5-triazacyclohexane-2,4,6-trione, etc., but are not limited to the above.

[0119] Examples of carbonyl compounds that serve as nitrogen-containing modifiers include: 1,3-dimethyl-2-imidazolidineone, 1-methyl-3-ethyl-2-imidazolidineone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidineone, N-methyl-2-pyrrolidone, N-methyl-2-piperidinone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, and methyl-2-pyridine. Acetyl ketone, methyl-4-pyridyl ketone, propyl-2-pyridyl ketone, di-4-pyridyl ketone, 2-benzopyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, N,N-diethylaminocarbamate, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylmethylpyridinamide, N,N-dimethylisonicotinamide, etc., but not limited to the above.

[0120] Examples of vinyl compounds that serve as modifiers containing nitrogen atoms include: N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylcis-butenediimide, N-methylphthalimide, N,N-bis(trimethylsilylacrylamide), α-linylacrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylbis(N,N-dimethylaniline), 4,4'-vinylbis(N,N-diethylaniline), 1,1-bis(4-α-linylphenyl)ethylene, 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene, etc., but are not limited to the above.

[0121] Regarding epoxy compounds that serve as modifiers containing nitrogen atoms, examples include hydrocarbon compounds containing epoxy groups bonded to amine groups, but this is not limited to these; they may further contain epoxy groups bonded to ether groups. Examples of such epoxy compounds include those represented by the general formula (a) below, but are not limited to them.

[0122] [Chemistry 5]

[0123] In formula (a) above, R is a divalent or higher hydrocarbon group, or an organic group having at least one polar group selected from ethers, epoxy groups, ketones, etc., which have oxygen polar groups; thioethers, thioketones, etc., which have sulfur polar groups; tertiary amino groups, imine groups, etc., which have nitrogen polar groups.

[0124] The divalent or higher hydrocarbon group can be a saturated or unsaturated straight-chain, branched, or cyclic hydrocarbon group, including alkyl, alkenyl, and phenyl groups. Preferably, it is a hydrocarbon group with 1 to 20 carbon atoms. Examples include: methylene, ethyl, butyl, cyclohexyl, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethyl)-cyclohexane, o-phenyl, m-phenyl, p-phenyl, m-xylene, p-xylene, bis(phenyl)-methane, etc.

[0125] In the above formula (a), R1 and R4 are hydrocarbon groups with 1 to 10 carbon atoms. R1 and R4 can be the same or different from each other. In formula (a) above, R2 and R5 are hydrogen or hydrocarbon groups with 1 to 10 carbon atoms. R2 and R5 can be the same or different from each other. In formula (a) above, R3 is a hydrocarbon group with 1 to 10 carbon atoms, or the structure of formula (a1) below. R1, R2, and R3 can be a ring structure that is bonded to each other. Furthermore, when R3 is a hydrocarbon group, it can also be a cyclic structure bonded to R. In the case of the aforementioned cyclic structure, it can be a form in which N and R bonded to R3 are directly bonded. In the above formula (a), n is an integer greater than or equal to 1, and m is an integer greater than or equal to 0 or 1.

[0126] [Chemistry 6]

[0127] In the above equation (a1), R1 and R2 are defined in the same way as R1 and R2 in the above equation (a). R1 ​​and R2 can be the same or different from each other.

[0128] Regarding epoxy compounds that serve as modifiers containing nitrogen atoms, those containing epoxy groups are preferred, and those containing glycidyl groups are even more preferred.

[0129] There is no particular limitation on the epoxy-containing hydrocarbon group bonded to an amino or ether group; examples include glycidylamino, diglycidylamino, or glycidoxy. More preferably, the molecular structure comprises compounds having an epoxy-containing group, such as glycidylamino or diglycidylamino, and glycidoxy, respectively; for example, compounds represented by the following general formula (a2) can be cited.

[0130] [Chemistry 7]

[0131] In formula (a2) above, R is defined in the same way as R in formula (a) above, and R6 is a hydrocarbon group with 1 to 10 carbon atoms or the structure of formula (a3) ​​below. When R6 is a hydrocarbon group, it can be a cyclic structure bonded to R. In this case, it can also be a form in which N and R bonded to R6 are directly bonded. In equation (a2), n is an integer greater than or equal to 1, and m is an integer greater than or equal to 0 or 1.

[0132] [Chemistry 8]

[0133] Epoxy compounds that serve as modifiers containing nitrogen atoms are preferably compounds having one or more diglycidylamino groups and one or more glycidyloxy groups in their molecules.

[0134] Examples of epoxy compounds used as nitrogen-containing modifiers include: N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxy-cyclohexane, 4-(4-glycidyloxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidyloxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidyloxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazolyl)-glycidyloxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-isophthalic acid. Methylamine, 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylamino)cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperyl)-(N,N-diglycidyl)aniline, 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidone, N,N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N,N-diglycidylaniline, N,N-diglycidylo-toluidine, N,N-diglycidylaminomethylcyclohexane, etc., but not limited to the above. Among the best of these are N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0135] From the viewpoint of effectively and reliably exerting the effect of the modified conjugated diene polymer of this embodiment, the modifier is preferably an alkoxysilane compound having a nitrogen atom. Examples of such modifiers include: 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-o-linylpropyltrimethoxysilane, 3-piperidinylpropyltriethoxysilane, 3-hexamethyleneiminepropylmethyldiethoxysilane, 3-(4-methyl-1-piperidinyl)propyltriethoxysilane, 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperidinyl)propyltriethoxysilane, 3-(3-Triethylsilyl-1-imidazolidine)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, tris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N',N'- Tetra(3-trimethoxysilylpropyl)ethylenediamine, 3-isocyanopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silazopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silazopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silazopentane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl) 1-aza-2-silazane, 2,2-dimethoxy-1-phenyl-1-aza-2-silazane, 2,2-diethoxy-1-butyl-1-aza-2-silazane, 2,2-dimethoxy-1-methyl-1-aza-2-silazane, 2,2-dimethoxy-8-(4-methylpiperyl)methyl-1,6-dioxa-2-silazane, 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silazane, etc., but not limited to the above.

[0136] <As a modifier for alkoxysilane compounds containing nitrogen atoms> The modified conjugated diene polymer of this embodiment is preferably modified using an alkoxysilane compound having a nitrogen atom. That is, it is preferably modified with modifier residues derived from an alkoxysilane compound having a nitrogen atom.

[0137] The following are particularly good examples of alkoxysilane compounds containing nitrogen atoms. Specifically, examples include: tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]amine, tetra(3-trimethoxysilylpropyl)-1,3-propanediamine (also known as "N,N,N',N'-tetra(3-trimethoxysilylpropyl)-1,3-propanediamine"), tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-aza-2-azacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3 -(1-methoxy-2-methyl-1-silaz-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-azacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, tri(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, tetra(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, penta(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, penta(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, tetra ...3-dimethyldiamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminodiamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminodiamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminodiamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminodiamine, tetra( -trimethoxysilylpropyl)-diethyltriamine, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silanecyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silanecyclopentane)propyl]silane [3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-(3-trimethoxysilylpropyl)silane, [3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silazopentanyl)propyl]silane, 3-Tris[2-(2,2-dimethoxy-1-aza-2-silazopentane)ethoxy]silyl-1-trimethoxysilylpropane, 1-[3-(1-methoxy-2-trimethylsilyl-1-silazopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)cyclohexane, 1-[3-(2,2-dimethoxy-1-aza-2-silazopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)cyclohexane, [3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)cyclohexane, 3,4,5-tris(3-trimethoxysilylpropyl)cyclohexyl-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl] ether, (3-trimethoxysilylpropyl) phosphate.

[0138] Examples of other phosphates include: bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl] phosphate, bis[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-(3-trimethoxysilylpropyl) phosphate, tris[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl] phosphate, N-(1,3-dimethylbutylene)-3-(triethoxysilyl)-1-propylamine, and N-(1,3-dimethylbutylene)-3-(trimethoxysilyl)-1-propylamine. Amines, N-benzyl-3-(triethoxysilyl)propane-1-amine, N-benzyl-3-(trimethoxysilyl)propane-1-amine, 1,1-(1,4-epenylphenyl)bis(N-(3(triethoxysilyl)propyl)methylamine), 1,1-(1,4-epenylphenyl)bis(N-(3(trimethoxysilyl)propyl)methylamine), 2-methoxy-2-methyl-1-(benzylaminoethyl)-1-aza-2-silazopentane, and 2-methoxy-2-methyl-1-(4-methoxybenzylaminoethyl)-1-aza-2-silazopentane.

[0139] Furthermore, examples include: 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-tetraethoxydisiloxane-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), 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).

[0140] Furthermore, examples include: 3,3'-(1,1,3,3-tetrapropoxydiasiloxane-1,3-diyl)bis(N,N-dipropylpropane-1-amine), 3,3'-(1,1,3,3-tetramethoxydiasiloxane-1,3-diyl)bis(N,N-diethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydiasiloxane-1,3-diyl)bis(N,N-diethylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-diethylmethane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-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-Tetrapropoxysiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxysiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxysiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxysiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxysiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxysiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), Disiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetramethoxydisiloxane, 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetraethoxydisiloxane, and 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetrapropoxydisiloxane.

[0141] Among modifiers containing nitrogen atoms, protected amine compounds formed by replacing active hydrogen with a protecting group can be exemplified by compounds containing alkoxysilanes and protected amines in their molecules. Examples of such compounds include: N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, and N,N-bis(trimethylsilyl)aminopropyltriethoxysilane. N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazolidinyl)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidine)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-imidazolidine)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-piperazolidinyl)propylmethyldiethoxysilane (-hexahydropyrimidinyl)propyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silazane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silazane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silazane, 2,2-Dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silazopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silazopentane, 2,2-diethoxy-1-butyl-1-aza-2-silazopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silazopentane, but not limited to the above.

[0142] For example, examples include: N-(1,3-dimethylbutylene)-3-methyl(dimethoxysilyl)-1-propane, N-(1,3-dimethylbutylene)-3-methyl(diethoxysilyl)-1-propane, N-(1-methylethylene)-3-(triethoxysilyl)-1-propane, N-(1-methylethylene)-3-(trimethoxysilyl)-1-propane, N-(1-methylethylene)-3-methyl(dimethoxysilyl)-1-propane, N-(1-methylethylene)-3-methyl(diethoxysilyl)-1-propane, N-ethylene-3-(triethoxysilyl)-1- Propylamine, N-Ethylene-3-(trimethoxysilyl)-1-propane, N-Ethylene-3-methyl(dimethoxysilyl)-1-propane, N-Ethylene-3-methyl(diethoxysilyl)-1-propane, N-(1-methylpropylene)-3-(triethoxysilyl)-1-propane, N-(1-methylpropylene)-3-(trimethoxysilyl)-1-propane, N-(1-methylpropylene)-3-methyl(dimethoxysilyl)-1-propane, N-(1-methylpropylene)-3-methyl(diethoxysilyl)-1-propane, N-benzylene-3-methyl(dimethoxysilyl)propane Alkyl-1-amine, N-benzyl-3-methyl(diethoxysilyl)propane-1-amine, N-4-methylbenzyl-3-(triethoxysilyl)propane-1-amine, N-4-methylbenzyl-3-(trimethoxysilyl)propane-1-amine, N-4-methylbenzyl-3-methyl(dimethoxysilyl)propane-1-amine, N-4-methylbenzyl-3-methyl(diethoxysilyl)propane-1-amine, N-naphthyl-3-(triethoxysilyl)propane-1-amine, N-naphthyl-3-methyl(dimethoxysilyl)propane-1-amine, N-naphthyl-3-methyl(dimethoxysilyl)propane-1-amine Alkyl-1-amine, 1,1-(1,4-epenylphenyl)bis(N-(3-methyl(dimethoxysilyl)propyl)methylamine), 1,1-(1,4-epenylphenyl)bis(N-(3-methyl(diethoxysilyl)propyl)methylamine), 2-ethoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silazopentane, and 2-methoxy-2-methyl-1-(methylisobutylaminoethyl)-1-aza-2-silazopentane, 1-trimethylsilyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-trimethylsilyl-4-[3-(triethoxysilyl)propyl]piperidine.

[0143] In the manufacturing steps of the modified conjugated diene polymer of this embodiment, when a coupling step is performed, it is preferable to use a modifier having nitrogen atoms represented by any one of the following formulas (A) to (D) in the coupling step. One of these modifiers may be used alone, or two or more may be used in combination.

[0144] [Chemistry 9]

[0145] Here, R10 and R11 are hydrocarbon groups with 1 to 12 carbon atoms, which may contain unsaturated bonds, and they may be the same or different. R12 is a hydrocarbon group with 1 to 20 carbon atoms. R8 and R9 are aliphatic hydrocarbon groups with 1 to 6 carbon atoms, which can contain unsaturated bonds, and they can be the same or different. R7 contains Si, O, or N, and is a hydrocarbon group with 1 to 20 carbon atoms that can be substituted by an organic group without active hydrogen, and may contain unsaturated bonds. a is an integer from 1 to 3.

[0146] [Chemistry 10]

[0147] In the above formula (B), A represents a hydrocarbon group with 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. R13, R14, and R15 each independently represent a single bond or an alkyl group having 1 to 20 carbon atoms. R16, R17, R18, R19, and R21 each independently represent an alkyl group having 1 to 20 carbon atoms. R20 and R22 each independently represent an alkyl group having 1 to 20 carbon atoms. R23 each independently represents an alkyl group having 1 to 20 carbon atoms, or a trialkylsilyl group. b each independently represents an integer from 1 to 3, c each independently represents 1 or 2, i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, and the sum of i, j, and k is an integer from 4 to 10.

[0148] [Chemistry 11]

[0149] In formula (C), R24, R25, R26, R27, R28, and R29 independently represent alkyl groups with 1 to 20 carbon atoms or aryl groups with 6 to 20 carbon atoms. R30, R31, and R32 each independently represent an alkyl group having 1 to 20 carbon atoms. s, t, and u each independently represent integers from 1 to 3, and the sum of s, t, and u is an integer greater than 4.

[0150] [Chemistry 12]

[0151] In formula (D), B1 and B2 are independently divalent hydrocarbon groups with 1 to 20 carbon atoms, with or without oxygen atoms. R33 to R36 are independently monovalent hydrocarbon groups with 1 to 20 carbon atoms. L1 to L4 are independently divalent, trivalent, or tetravalent alkylsilyl groups or monovalent hydrocarbon groups with 1 to 20 carbon atoms substituted with alkyl groups with 1 to 10 carbon atoms, or L1 and L2, and L3 and L4 can be linked together to form a ring with 1 to 5 carbon atoms. When L1 and L2, and L3 and L4 are linked together to form a ring, the formed ring can contain one to three heteroatoms selected from the group consisting of N, O, and S.

[0152] Specifically, in the above formula (D), B1 and B2 independently represent 1 to 10 alkyl groups, R33 to R36 are independently alkyl groups with 1 to 10 carbon atoms, L1 to L4 are independently tetravalent alkyl groups silyl groups substituted with alkyl groups with 1 to 5 carbon atoms, alkyl groups with 1 to 10 carbon atoms, or L1 and L2 can be linked with L3 and L4 to form a ring with 1 to 3 carbon atoms. When L1 and L2 are linked with L3 and L4 to form a ring, the formed ring may contain 1 to 3 heteroatoms selected from the group consisting of N, O and S.

[0153] Examples of modifiers used in the coupling step represented by formula (A) above include: 1-methyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-methyl-4-[3-(triethoxysilyl)propyl]piperidine, 1-propyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-propyl-4-[3-(triethoxysilyl)propyl]piperidine, 1-trimethylsilyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-trimethylsilyl-4-[3-(triethoxysilyl)propyl]piperidine, but are not limited to the above.

[0154] Of these, from the viewpoints of improving the reactivity and interaction between the modified conjugated diene polymer of this embodiment and inorganic fillers such as silicon dioxide, and from the viewpoints of improving processability, it is preferable that a is 3 in the above formula (A).

[0155] There are no particular limitations on the reaction temperature and reaction time in the coupling step of using the modifier represented by formula (A) above, but it is preferred to react at a temperature above 0°C and below 120°C, and preferably for a reaction time of 30 seconds or more.

[0156] The amount of modifier represented by formula (A) above is preferably such that the total number of alkoxy groups bonded to the silyl group in the compound represented by formula (A) is in the range of 0.3 times or more and 4.0 times or less of the number of added moles required to become a polymerization initiator, more preferably in the range of 0.5 times or more and 3 times or less, and even more preferably in the range of 0.6 times or more and 2.0 times or less. From the viewpoint of setting the molecular weight of the obtained modified conjugated diene polymer in a more favorable range, it is preferably set to 0.3 times or more, and from the viewpoint of storage stability during long-term storage, it is preferably set to 4.0 times or less.

[0157] More specifically, the amount of polymerization initiator and the amount of modifier represented by formula (A) added can be adjusted such that the mole number of the modifier represented by formula (A) is preferably more than 0.1 times and less than 1.0 times that of the mole number of the polymerization initiator.

[0158] In the above formula (B), A is preferably represented by any one of the following formulas (I) to (IV).

[0159] [Chemistry 13] (Chemical I)

[0160] In formula (I), D1 represents a single bond or a divalent hydrocarbon group with 1 to 20 carbon atoms. h represents an integer from 1 to 10. When there are multiple D1s, each D1 is independent.

[0161] [Chemistry 14] (Chemical II)

[0162] In formula (Chemical II), D2 represents a single bond or a divalent hydrocarbon group with 1 to 20 carbon atoms. D3 represents an alkyl group with 1 to 20 carbon atoms, and h represents an integer from 1 to 10. When there are multiples of D2 and D3, D2 and D3 are independent.

[0163] [Chemistry 15] (Chemical III)

[0164] In formula (Chem. III), D4 represents a single bond or a divalent hydrocarbon group with 1 to 20 carbon atoms. h represents an integer from 1 to 10. When there are multiple D4s, each D4 is independent.

[0165] [Chemistry 16] (Chemical IV)

[0166] In formula (Chem. IV), D5 represents a single bond or a divalent hydrocarbon group with 1 to 20 carbon atoms. h represents an integer from 1 to 10. When there are multiple D5s, each D5 is independent.

[0167] In formula (B) above, examples of modifiers used when A is represented by formula (I) include: tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]amine, and bis[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]- (3-Trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]amine, tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]amine, bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]amine, bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]amine [-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)amine, tris[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]amine, tetra(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]amine [1,3-Propanediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-(3-trimethoxysilylpropyl)-1,3-propanediamine, but not limited to the above.

[0168] For example, examples include: tetra[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2 ... Tris[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-silazpentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-propanediamine, tetra(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazpentane)propyl]-1,3-propanediamine.

[0169] Furthermore, examples include: bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetra ... and tetra[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine. 2-Diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza- 2-Silazopentanyl)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-azacyclopentane)propyl]-1,3-propanediamine [-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silazacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silaza-2-azacyclopentane)propyl]-1,3-propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane.

[0170] Furthermore, examples include: tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-1,3-diaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-1,3-diaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, tetra[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)propyl )-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-azacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis[3-(2,2-dimethoxy-1-aza-2-azacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane.

[0171] Furthermore, examples include: tris[3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-1,3-diaminomethylcyclohexane, tetra(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-diaminomethylcyclohexane, bis(3- Triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-diaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetra[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethyl] [3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-1,3-diaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-aza-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-aza-2-silazopentanyl)propyl]-(3-triethoxysilylpropyl)-[3 -(1-ethoxy-2-trimethylsilyl-1-silazane-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silazane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silazane-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, tetra(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, and penta(3-trimethoxysilylpropyl)-diethyltriamine.

[0172] In formula (B) above, examples of modifiers used when A is represented by formula (Chemical II) include: tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazane] [3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N1,N1'-(propane-1,3-diyl)bis(N1-methyl-N3,N3-bis(3-(trimethoxysilyl)propyl)-1,3-propanediamine), and N1-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N1-methyl-N3-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine, but not limited to the above.

[0173] In formula (B) above, examples of modifiers used when A is represented by formula (Chemical III) include: tetrakis[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2-silazane)propyl]-[3-(1-methoxy- 2-Trimethylsilyl-1-silaz-2-azacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silazpentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silazpentane)propyl]silane, bis [3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silazylpentane)propyl]silane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazylpentane)propyl]silane, bis(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silaz-2-azacyclopentane)propyl]silane [3-(2,2-dimethoxy-1-aza-2-silazopentanyl)propyl]silane, bis[3-(1-methoxy-2-trimethylsilyl-1-silazopentanyl)propyl]-bis(3-trimethoxysilylpropyl)silane, and bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-silazopentanyl)propyl]silane, but not limited to the above.

[0174] In formula (B) above, examples of modifiers used when A is represented by formula (Chemical IV) include: 3-tris[2-(2,2-dimethoxy-1-aza-2-silazane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silazane)propane and 3-tris[2-(2,2-dimethoxy-1-aza-2-silazane)ethoxy]silyl-1-trimethoxysilylpropane, but not limited to the above.

[0175] The amount of modifier added as represented by formula (B) above is preferably determined based on the ratio of the number of moles added to the number of moles added to the modifier as represented by formula (B). In this way, the reaction between the conjugated diene polymer and the modifier can be adjusted to meet the desired stoichiometric ratio.

[0176] More specifically, the amounts of the polymerization initiator and the coupling modifier represented by formula (B) can be adjusted such that the molar number of the modifier represented by formula (B) is preferably 0.012 times or more and 1.0 times or less, and more preferably 0.02 times or more and 0.5 times or less, relative to the molar number of the polymerization initiator. In this case, in formula (B) above, the functional group of the modifier (e.g., when i and j are 2 or more, and there are multiples of b and c, and when b and c are equal, it is b×i+(c+1)×j+k) is preferably an integer from 5 to 10, and more preferably an integer from 6 to 10. From the viewpoint of setting the molecular weight of the obtained modified conjugated diene polymer to a preferred range, it is preferably set to 0.012 times or more. Furthermore, from the viewpoint of storage stability during long-term storage, it is preferably set to 0.2 times or less.

[0177] Examples of modifiers represented by formula (C) above 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, but are not limited to the above.

[0178] Of these, from the viewpoints of improving the reactivity and interaction between modified conjugated diene polymers and inorganic fillers such as silicon dioxide, and from the viewpoints of improving processability, it is preferable that in the above formula (C), s, t, and u are all 3.

[0179] Regarding the reaction temperature and reaction time in the coupling step using the coupling modifier represented by the above formula (C), it is not limited to the following, but it is preferred to react at a temperature above 0°C and below 120°C, and preferably for a reaction time of 30 seconds or more.

[0180] Regarding the amount of modifier added as represented by formula (C) above, it is preferable that the total number of alkoxy groups bonded to the silyl group in the compound represented by formula (C) is in the range of 0.1 times or more and 2.0 times or less of the number of added moles required to become a polymerization initiator, 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 the molecular weight of the obtained modified conjugated diene polymer, it is preferable to set it to 0.1 times or more. Furthermore, from the viewpoint of storage stability during long-term storage, it is preferable to set it to 2.0 times or less.

[0181] Examples of modifiers represented by formula (D) above include: 3,3'-(1,1,3,3-tetramethoxysiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-1,1,3,3-tetraethoxysiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), and 3,3'-(1,1,3,3-tetrapropoxysiloxane-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), etc., but not limited to the above.

[0182] There are no particular limitations on the reaction temperature and reaction time in the coupling step of using the modifier represented by the above formula (D), but it is preferred to be above 0°C and below 120°C, and preferably the reaction time is above 30 seconds.

[0183] Regarding the amount of modifier added as represented by formula (D) above, the total number of moles of alkoxy groups bonded to silyl groups in the compound represented by formula (D) is preferably in the range of 0.25 times or more and 2.0 times or less than the number of added moles of the polymerization initiator, more preferably in the range of 0.3 times or more and 1 time or less, and even more preferably in the range of 0.35 times or more and 0.5 times or less. From the viewpoint of the molecular weight of the obtained modified conjugated diene polymer and from the viewpoint of storage stability during long-term storage, it is preferably set to 2.0 times or less.

[0184] [Method for manufacturing conjugated diene polymers] The method for manufacturing the modified conjugated diene polymer of this embodiment includes a polymerization step: using a continuous reactor with two or more reactors connected in series, a lithium compound is used as a polymerization initiator to polymerize at least one conjugated diene compound. The aforementioned continuous reactor has a monomer addition section, during which at least one conjugated diene compound and an aromatic vinyl compound are added during the polymerization step; and The manufacturing method includes a coupling step: reacting the conjugated diene polymer obtained by the above polymerization step with a modifier having nitrogen atoms.

[0185] (Polymerization initiator) At least organic monolithium compounds can be used as polymerization initiators. Examples of organic single-lithium compounds include, for example, low-molecular-weight compounds and soluble oligomers of organic single-lithium compounds, but they are not limited to the above. Furthermore, as organic monolithium compounds, examples of compounds with carbon-lithium bonds, nitrogen-lithium bonds, and tin-lithium bonds can be cited in terms of the bonding form between the organic group and the lithium. The optimal amount of organic monolithium compound used as a polymerization initiator is determined based on the molecular weight of the target conjugated diene polymer or the modified conjugated diene polymer. The amount of monomers such as conjugated diene compounds used is related to the degree of polymerization, relative to the amount of polymerization initiator. That is, it tends to be related to the number average molecular weight and the weight average molecular weight. Therefore, in order to increase the molecular weight, the amount of polymerization initiator used can be reduced, and in order to decrease the molecular weight, the amount of polymerization initiator used can be increased.

[0186] When introducing nitrogen atoms into a conjugated diene polymer using a polymerization initiator, from the viewpoint of using one method for introducing nitrogen atoms into a conjugated diene polymer, the organic monolithium compound is preferably an alkyl lithium compound having a substituted amine group, or a dialkylamino lithium compound. In this case, a conjugated diene polymer having a nitrogen atom containing an amine group at the polymerization initiation end can be obtained. Substituted amine groups are amine groups that do not have active hydrogen or whose active hydrogen is protected. Alkyl lithium compounds having an amine group that does not have active hydrogen, for example, include: 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium, but are not limited to the above. Examples of alkyl lithium compounds with an amine group that has a structure that protects active hydrogen include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium. Examples of dialkylaminolithium compounds include: lithium dimethylaminoamine, lithium diethylaminoamine, lithium dipropylaminoamine, lithium dibutylaminoamine, lithium di-n-hexylaminoamine, lithium diheptylaminoamine, lithium diisopropylaminoamine, lithium dioctylaminoamine, lithium di-2-ethylhexylaminoamine, lithium didecylaminoamine, lithium ethylpropylaminoamine, and ethylaminoamine. Lithium butylamide, lithium ethylbenzylamide, lithium methylphenylethylamide, lithium hexamethylene amide, lithium pyrrolidine, lithium piperidinium, lithium heptamethylene amide, lithium α-porphyrin, 1-lithium-azacyclooctane, 6-lithium-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithium-1,2,3,6-tetrahydropyridine, but not limited to the above. These organolithium compounds with substituted amine groups can also react in small amounts with polymerizable monomers, such as 1,3-butadiene, isoprene, styrene, etc., to become organolithium compounds used as soluble oligomers.

[0187] Furthermore, the polymerization initiator can be generated by reacting an aromatic vinyl compound with a substituted amine group and / or a conjugated diene compound with an organolithium compound, or it can be a compound that can introduce a functional group at one end of a polymer chain. From the viewpoint of ease of industrial availability and ease of controlling the polymerization reaction, alkyl lithium compounds are preferred as the aforementioned organic monolithium compounds. In this case, conjugated diene polymers having an alkyl group at the polymerization initiation end can be obtained. Examples of the aforementioned alkyl lithium compounds include, but are not limited to, n-butyllithium, secondary butyllithium, tertiary butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and arsenic lithium. From the viewpoint of ease of industrial availability and ease of controlling the polymerization reaction, n-butyllithium and secondary butyllithium are preferred as alkyllithium compounds. These organolithium compounds can be used alone or in combination with two or more. They can also be used in combination with other organometallic compounds. Other organometallic compounds mentioned above include, for example, alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds. Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Also examples include alkoxides, sulfonates, carbonates, and amides of alkaline earth metals. Examples of organomagnesium compounds include, for example, dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include, for example, organoaluminum compounds.

[0188] The weight-average molecular weight of the conjugated diene polymer exiting the polymerization step is controlled by the amount of polymerization initiator used relative to the amount of conjugated diene compound and aromatic vinyl compound. A decrease in the amount of polymerization initiator tends to result in a lower weight-average molecular weight. When the total mass of the conjugated diene compound and aromatic vinyl compound used is set to 100 kg, the amount of polymerization initiator used is preferably 0.15 mol or more and 1.5 mol or less.

[0189] (Polar substances) In the method for manufacturing the modified conjugated diene polymer of this embodiment, a polar substance may be added together with the polymerization initiator. Polar substances can randomly copolymerize aromatic vinyl compounds with conjugated diene compounds, and they also tend to act as vinylizing agents to control the microstructure of the conjugated diene portion. Furthermore, they tend to be effective in promoting polymerization reactions.

[0190] Examples of polar substances include: tetrahydrofuran, diethyl ether, dialkyl, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis(2-tetrahydrofuranyl)propane, and other ethers; tetramethylethylenediamine, dipiperidinyl ethane, trimethylamine, triethylamine, pyridine, etc. Tertiary amine compounds such as pyridine; alkali metal alkane oxides such as potassium tertiary valerate, potassium tertiary butyrate, sodium tertiary butyrate, and sodium valerate; and phosphine compounds such as triphenylphosphine, but not limited to the above. These polar substances can be used alone or in combination with two or more.

[0191] There is no particular limitation on the amount of polar substance used, and it can be selected according to the purpose, but it is preferred to be 0.005 mol or more and 100 mol or less relative to 1 mol of polymerization initiator.

[0192] This polar substance can be used as a regulator of the microstructure of the conjugated diene moiety in the modified conjugated diene polymer of this embodiment, and can be used in appropriate amounts according to the desired amount of vinyl bonds. Most polar substances simultaneously exhibit effective randomization effects in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to adjust the randomness of aromatic vinyl monomer units and conjugated diene monomer units in each polymer chain segment.

[0193] (Aggregation Step) In the method for manufacturing modified conjugated diene polymers according to this embodiment, the polymerization step is carried out in a continuous reactor system with two or more reactors connected in series, and includes: a polymerization step (P1) to obtain a first polymer segment and a polymerization step (P2) to obtain a second polymer segment. The above polymerization steps (P1) and (P2) are distinguished by the following monomer addition portion. The polymerization steps (P1) and (P2) described above can be carried out using one or more reactors connected together. The reactor shape can be a tank type or a tube type with an agitator. Polymerization steps (P1) and (P2) do not need to be assigned to individual reactors. For example, polymerization step (P2) can be set to start downstream of the first reactor. However, from the viewpoint of ease of polymerization control, it is preferable to assign more than one reactor to each polymerization step (P1) and (P2). Each reactor can have its own temperature control function.

[0194] (Amount of solid matter) In the method for manufacturing modified conjugated diene polymers according to this embodiment, the target modified conjugated diene polymer can be recovered with a specified amount of solids. Furthermore, the solids content in this specification refers to the mass of the modified conjugated diene polymer recovered per unit time at the measurement point. The mass of modified conjugated diene polymers includes only those polymerized by reaction with polymerization initiators; unreacted conjugated diene compounds, aromatic ethylene compounds, solvents, etc., are not included in the mass.

[0195] (Conversion rate) In the method for manufacturing modified conjugated diene polymers according to this embodiment, "conversion rate" is defined as the mass of the conjugated diene compound added at the time of measurement and the mass of the aromatic vinyl compound at the time of measurement, which is the mass of the polymer that has completed the reaction and become a conjugated diene polymer. That is, using the above solids quantity, and using the following formula (2) to calculate it.

[0196] [Number 5]

[0197] Furthermore, the amount of bonded conjugated diene monomer units and the amount of bonded aromatic vinyl monomer units of the solid components obtained by the above solid content determination are used respectively, and the conversion rates of each conjugated diene compound and aromatic vinyl compound are calculated using the following formulas (3) and (4).

[0198] [Number 6]

[0199] The conversion rate in the above polymerization step (P1) is preferably 80% or higher, more preferably 85% or higher, and even more preferably 90% or higher. By keeping the polymerization conversion rate within the above range, the conversion rate is less likely to change due to interference in continuous polymerization, thus improving manufacturing stability.

[0200] The conversion rate of the aromatic vinyl compound in the polymerization intermediate in the above polymerization step (P1) is preferably 70% or more, more preferably 75% or more, and even more preferably 80% or more. When the conversion rate of the aromatic vinyl compounds is outside the aforementioned range, there is a tendency for the aromatic vinyl monomer units to be distributed more significantly towards the second polymer segment, and the tanδ peak height to decrease. On the other hand, if the conversion rate of the aromatic vinyl compounds is within the aforementioned range, there is a tendency for the distribution of the aromatic vinyl monomer units to become more uniform, and the tanδ peak height to increase. Especially when the amount of polar substances added is small and the amount of aromatic vinyl compounds added is large, the conversion rate of aromatic vinyl compounds tends to deviate from the above range.

[0201] From the viewpoint of ease of control over the polymerization process, the conversion rate in the above polymerization step (P2) is preferably above 95%.

[0202] The conversion rates of the aromatic vinyl compounds in the polymerization intermediates in the polymerization step (P1) and the conversion rates of the aromatic vinyl compounds in the polymerization step (P2) can be controlled by adjusting the type and amount of polar substances, polymerization temperature, monomer and polymerization initiator concentrations in the raw material solution, and residence time.

[0203] In the modified conjugated diene manufacturing method of this embodiment, a first polymer segment is obtained in the polymerization step (P1), and in the polymerization step (P1), it is preferable to have a raw material supply section that continuously supplies conjugated diene compound, aromatic vinyl compound, inert solvent, polymerization initiator and polar substance from one end of the reactor, and a discharge section that continuously discharges polymer solution from the end opposite to the raw material supply section.

[0204] The amount of the aromatic vinyl monomer unit X1 in the first polymer segment can be controlled by adjusting the mass ratio of the aromatic vinyl compound to the conjugated diene compound added in the polymerization step (P1).

[0205] The amount of vinyl bonds Y1 in the conjugated diene of the first polymer segment can be controlled by adjusting the amount of polar substance added in the polymerization step (P1) and the polymerization temperature.

[0206] The conjugated diene polymer solution after the polymerization step (P1) is continuously distilled from the reactor and transported to the next step. Preferably, the destination of the liquid transport is, for example, the polymerization step (P2) of the second polymer segment described below. Furthermore, the starting point of the polymerization step (P2) is defined as the monomer addition section mentioned above.

[0207] In the method for manufacturing modified conjugated diene polymers according to this embodiment, it is preferable to have a polymerization step (P2) in which a monomer addition section for adding a new raw material compound is added after the polymerization step (P1), and a second polymer segment is introduced into the end of the first polymer segment, wherein the amount of vinyl bonds in the bonded conjugated diene of the second polymer segment is greater than that synthesized in the polymerization step before the polymerization step (P2).

[0208] The configuration of the junction between polymerization steps (P1) and (P2) where the monomer addition section is located is not particularly limited, but from the viewpoint of preventing backflow of the polymer solution, it is preferably a pipe, and more preferably located between the pipes of the first reactor and the second reactor in the continuous reactor. Furthermore, the added raw material compound is preferably a conjugated diene compound, an aromatic vinyl compound, or a polar substance. From the viewpoint of improving the fuel-saving performance of the modified conjugated diene polymer sulfide in this embodiment, it is more preferably a conjugated diene compound, an aromatic vinyl compound, a polar substance, or the branching agent described below. An inert solvent may be added to the monomer addition section.

[0209] The lower limit of the total mass of the conjugated diene compound and aromatic vinyl compound added in the monomer addition section, relative to the total mass of the conjugated diene compound and aromatic vinyl compound added in the entire polymerization step, is preferably 10% or more, more preferably 15% or more, and even more preferably 18% or more. Furthermore, the upper limit of the total mass of the conjugated diene compound and aromatic vinyl compound added in the monomer addition section, relative to the total mass of the conjugated diene compound and aromatic vinyl compound added in the entire polymerization step, is preferably 90% or less, more preferably 80% or less, and even more preferably 50% or less. Within the aforementioned range, there is a tendency to more significantly improve the opposite of wet grip performance and abrasion resistance.

[0210] The amount of the aromatic vinyl monomer unit X2 in the second polymer segment can be controlled by adjusting the mass ratio of the aromatic vinyl compound to the conjugated diene compound added in the polymerization step (P2) above.

[0211] The amount of vinyl bonds Y2 in the bonded conjugated diene of the second polymer segment can be controlled by adjusting the amount of polar compound added in the above polymerization step (P2) and the polymerization temperature.

[0212] The conjugated diene polymer solution after the polymerization step (P2) is continuously distilled from the reactor and transported to the next step. As an example, the destination of the liquid transport could be the following coupling step.

[0213] The polymer segment ratio is controlled by adjusting the ratio of the mass of monomer added in polymerization step (P1) to the mass of monomer added in polymerization step (P2), and the conversion rates of polymerization steps (P1) and (P2) respectively. To increase the ratio of the first polymer segment, it is only necessary to increase the ratio of monomer added in polymerization step (P1) and increase the polymerization conversion rate in polymerization step (P1).

[0214] When manufacturing the modified conjugated diene polymer of this embodiment, predetermined steps may be included before and after polymerization step (P1) and before and after polymerization step (P2). For example, a step of synthesizing a polymer that is different from the first polymer segment or the second polymer segment may be included.

[0215] In the method for manufacturing the modified conjugated diene polymer of this embodiment, the polymerization temperature in the polymerization step is preferably the temperature for conducting living anionic polymerization. From a production point of view, it is more preferably 0°C or higher and 120°C or lower, and even more preferably 50°C or higher and 100°C or lower. By being within this range, it is possible to sufficiently ensure the amount of reaction of the modifier with the active end after polymerization. Even more preferably, it is 70°C or higher and 95°C or lower.

[0216] In the method for manufacturing modified conjugated diene polymers according to this embodiment, in order to obtain a higher molecular weight distribution, it is only necessary to reduce the height (L) / diameter (D) of the trough reactor. By reducing L / D, the residence time distribution within the reactor increases, thus increasing the difference in reaction time among the various polymerization initiator molecules and tending to increase the molecular weight distribution. Furthermore, the molecular weight distribution can vary depending on the type of coupling agent used.

[0217] (Coupling Steps) In the method for manufacturing the modified conjugated diene polymer of this embodiment, a coupling step is performed. This coupling step involves modifying the active ends of the conjugated diene polymer obtained by polymer segment polymerization using a modifier with nitrogen atoms (preferably an alkoxysilane modifier with nitrogen atoms). In the coupling step, one of the active ends of the conjugated diene polymer is modified using a modifier with nitrogen atoms to obtain the modified conjugated diene polymer.

[0218] The method for manufacturing modified conjugated diene polymers in this embodiment may include a condensation reaction step after the coupling step and / or before the coupling step, wherein the condensation reaction step is generated by adding a condensation accelerator.

[0219] In the method for manufacturing the modified conjugated diene polymer of this embodiment, after the coupling step, deactivating agents and / or neutralizing agents may be added to the polymer solution as needed. Examples of deactivating agents include, but are not limited to, water, methanol, ethanol, and isopropanol. Examples of neutralizing agents include: stearic acid, oleic acid, and partial decacarbonate (a mixture of carboxylic acids with 9 to 11 carbon atoms, with 10 carbon atoms as the main component), aqueous solutions of carboxylic acids and inorganic acids, as well as carbon dioxide, but are not limited to the above.

[0220] From the perspective of preventing gel formation after polymerization and improving stability during processing, it is preferable to add a rubber stabilizer to the modified conjugated diene polymer of this embodiment. As a stabilizer for rubber, it is not limited to the following substances, and well-known substances can be used, such as preferably 2,6-di-tert-butyl-4-hydroxytoluene (BHT), octadecyl 3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, 2-methyl-4,6-bis[(octylthio)methyl]phenol and other antioxidants.

[0221] (Steps for obtaining polymers from polymer solutions) The method for manufacturing modified conjugated diene polymers according to this embodiment may include a step of obtaining the modified conjugated diene polymer from a polymer solution. As such a method, known methods may be used, for example, the methods described below. Examples include: separating the solvent by steam stripping, filtering the modified conjugated diene polymer, and then dehydrating and drying it to obtain the modified conjugated diene polymer; concentrating it in a flash tank and then evaporating it using an exhaust extruder or similar method to obtain the modified conjugated diene polymer; and directly evaporating it using a rotary dryer or similar method to obtain the modified conjugated diene polymer.

[0222] (Steps to obtain oil-extended conjugated diene polymers) In the method for manufacturing modified conjugated diene polymers according to this embodiment, at least one of the group consisting of filler oil, liquid rubber and resin can be added to the manufactured modified conjugated diene polymer to produce an oil-extended modified conjugated diene polymer. Furthermore, oil-extended modified conjugated diene polymers include not only oil-extended modified conjugated diene polymers containing oil, but also those containing liquid polybutadiene or various resins other than oil. This can further improve the processability of modified conjugated diene polymers.

[0223] A preferred method for adding filler oil to modified conjugated diene polymers is to add filler oil to a modified conjugated diene polymer solution and mix them to form an oil-extended polymer solution, and then desolventize the oil-extended polymer solution, but the method is not limited to the above. Examples of filler oils include aromatic oils, naphthenic oils, paraffin oils, and vegetable oils. Vegetable oils can be made from oils selected from the group consisting of linseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, castor oil, tung oil, pine oil, sunflower oil, palm oil, olive oil, coconut oil, peanut oil, and grapeseed oil. Among these, from the perspectives of environmental safety, preventing oil seepage, and improving wetland grip, aromatic oil substitutes with a polycyclic aromatic hydrocarbon (PCA) content of less than 3% by mass based on the IP346 standard are preferred. As alternatives to aromatic oils, for example, in addition to TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), RAE (Residual Aromatic Extracts) can also be cited.

[0224] Examples of liquid rubbers include liquid polybutadiene, liquid styrene-butadiene rubber, etc., but are not limited to these. Examples of resins include: aromatic petroleum resins, benzofuran-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, oligomers of monoolefins, oligomers of dienes, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, esters of hydrogenated oil resins and monofunctional or polyfunctional alcohols, but are not limited to the above. These resins can be used alone or in combination with two or more. When hydrogenation is performed, all unsaturated groups can be hydrogenated, or some can remain. The amount of any one of the following selected materials, namely, filler oil, liquid rubber and resin, is not particularly limited, but is preferably 1 to 60 parts by weight, more preferably 10 to 60 parts by weight, and even more preferably 15 to 37.5 parts by weight, relative to 100 parts by weight of the conjugated diene polymer of this embodiment.

[0225] [Rubber Composition] The modified conjugated diene polymer of this embodiment can be supplemented with fillers to prepare a rubber composition (hereinafter, sometimes referred to as the rubber composition of this embodiment). The rubber composition using the modified conjugated diene polymer of this embodiment comprises: a rubber component containing the modified conjugated diene polymer of this embodiment; and a filler, which is 5.0 parts by mass or more and 150 parts by mass or less relative to 100 parts by mass of the rubber component, and preferably the rubber component contains 10 parts by mass or more of the modified conjugated diene polymer of this embodiment relative to 100 parts by mass of the total rubber component. By dispersing the filler in the rubber component containing the modified conjugated diene polymer of this embodiment, a rubber composition with better processability during vulcanization, and with better low hysteresis loss, destructive properties, and abrasion resistance of its vulcanizate can be obtained. Furthermore, by including the modified conjugated diene polymer of this embodiment in the rubber component at a predetermined ratio, there is a tendency to further improve processability and abrasion resistance.

[0226] Examples of fillers include, but are not limited to, silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. This is especially true when the rubber composition is used in applications such as tires, vibration-damping rubber for automotive parts, and vulcanized rubber for shoes. Such fillers can be used alone or in combination with two or more.

[0227] There are no particular limitations on the silica-based inorganic filler, and known materials can be used. However, it is preferred to use solid particles containing SiO2 or Si3Al as structural units, and more preferably solid particles containing SiO2 or Si3Al as the main structural unit. Here, the main component refers to a component that contains more than 50% by mass, more preferably 70% by mass, and more preferably 80% by mass in the silica-based inorganic filler.

[0228] Examples of silica-based inorganic fillers include, but are not limited to, silica, clay, talc, mica, diatomaceous earth, silash, montmorillonite, zeolite, and glass fibers. Silica-based inorganic fillers with hydrophobic surfaces, and mixtures of silica-based inorganic fillers with inorganic fillers other than silica-based fillers, can also be used. From the viewpoint of further improving the strength and abrasion resistance of the rubber composition of this embodiment, silica or glass fibers are preferred, with silica being more preferred. There is no particular limitation on the silica used; examples include dry silica, wet silica, and synthetic silicate silica. From the viewpoint of further improving the breaking strength of the rubber composition, wet silica is preferred.

[0229] From the viewpoint of obtaining a rubber composition with practically good abrasion resistance and breaking strength, the nitrogen adsorption specific surface area of ​​the silica-based inorganic filler determined by the BET adsorption method is preferably 100 m² / g or more and 300 m² / g or less, more preferably 170 m² / g or more and 250 m² / g or less. Furthermore, silica-based inorganic fillers with relatively small specific surface areas (e.g., less than 200 m² / g) and silica-based inorganic fillers with relatively large specific surface areas (e.g., 200 m² / g or more) can be used in combination as needed. Especially when using silica-based inorganic fillers with relatively large specific surface areas (e.g., 200 m² / g or more), the dispersibility of silica in the rubber composition of this embodiment is further improved. As a result, there is a tendency to obtain a rubber composition with superior abrasion resistance, breaking strength, and low hysteresis loss.

[0230] Examples of carbon black include, but are not limited to, various grades such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black with a nitrogen adsorption specific surface area of ​​50 m² / g or more as determined by the BET adsorption method and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0231] As a metal oxide, there are no particular limitations as long as it is a solid particle with the chemical formula MxOy (M represents a metal atom, and x and y independently represent integers from 1 to 6) as the main component of the structural unit. Examples include aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide.

[0232] There are no particular limitations on what constitutes a metal hydroxide; examples include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0233] Relative to 100 parts by weight of the rubber component, the filler content in the rubber composition using the modified conjugated diene polymer of this embodiment is preferably 5.0 parts by weight or more and 150 parts by weight, more preferably 20 parts by weight or more and 100 parts by weight or less, and even more preferably 30 parts by weight or more and 90 parts by weight or less. By satisfying the above range with the filler, the rubber composition tends to have better processability during vulcanization, and its vulcanizates tend to have lower hysteresis loss, destructive properties, and abrasion resistance.

[0234] From the viewpoint of reliably imparting the performance required for applications such as tires, including dry grip and electrical conductivity, the rubber composition using the modified conjugated diene polymer of this embodiment preferably contains 0.5 parts by weight and 100 parts by weight of carbon black, relative to 100 parts by weight of the rubber component containing the conjugated diene polymer of this embodiment. Similarly, from the viewpoint of this embodiment, the rubber composition preferably contains 3.0 parts by weight and 100 parts by weight of carbon black, and more preferably 5.0 parts by weight and 50 parts by weight of carbon black, relative to 100 parts by weight of the rubber component containing the modified conjugated diene polymer of this embodiment.

[0235] The rubber composition using the modified conjugated diene polymer of this embodiment may further include a silane coupling agent. By including a silane coupling agent in the rubber composition, the interaction between the rubber components and the fillers can be further improved. As a silane coupling agent, a compound having a sulfur bond moiety and an alkoxysilyl or silanol moiety in one molecule is preferred, but not limited to the above. Examples of such compounds include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide, but not limited to the above.

[0236] In the rubber composition using the modified conjugated diene polymer of this embodiment, the content of silane coupling agent relative to 100 parts by mass of filler 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 parts by mass or more and 15 parts by mass or less. If the content of silane coupling agent is within the above range, there is a tendency to further improve the interaction between the rubber component and the filler.

[0237] The rubber composition using the modified conjugated diene polymer of this embodiment may include rubber-like polymers (hereinafter referred to as "rubber-like polymers") other than the modified conjugated diene polymer of this embodiment as rubber components. Examples of rubber-like polymers include, but are not limited to, conjugated diene polymers and their hydrides, random copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrides, block copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrides, non-diene polymers, and natural rubber. Examples of rubber-like polymers include, but not limited to, 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, styrene-isoprene block copolymers and their hydrogenated derivatives, and acrylonitrile-butadiene rubber and its hydrogenated derivatives. Examples of non-diene polymers include, but are not limited to, olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, polysiloxane rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber. Examples of natural rubber include RSS3-5, SMR, and epoxidized natural rubber used in smoked sheets, but are not limited to these.

[0238] The rubber-like polymer can be a modified rubber endowed with polar functional groups such as hydroxyl and amine groups. When the rubber composition using the modified conjugated diene polymer of this embodiment is used as a tire material, the rubber-like polymer is preferably selected from one or more of the group consisting of butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber.

[0239] From the viewpoint of balancing the abrasion resistance, breaking strength, low hysteresis loss, and processability of the rubber composition, the mass-average molecular weight of the rubber-like polymer is preferably 2,000 or more and 2,000,000 or less, and more preferably 5,000 or more and 1,500,000 or less. Furthermore, low molecular weight rubber-like polymers, i.e., so-called liquid rubbers, can also be used as rubber-like polymers. These rubber-like polymers can be used alone or in combination of two or more.

[0240] When a rubber composition using the modified conjugated diene polymer of this embodiment includes not only the modified conjugated diene polymer of this embodiment but also the aforementioned rubbery polymer, the content ratio (mass ratio) of the modified conjugated diene polymer to the rubbery polymer (modified conjugated diene polymer / rubbery polymer) is preferably 10 / 90 or more and 100 / 0 or less, more preferably 20 / 80 or more and 90 / 10 or less, and even more preferably 30 / 70 or more and 80 / 20 or less. That is, in the rubber component, relative to 100 parts by mass of the total rubber component, it is preferable to include 10 parts by mass and 100 parts by mass of the modified conjugated diene polymer of this embodiment, more preferably 20 parts by mass and 90 parts by mass of the modified conjugated diene polymer of this embodiment, and even more preferably 30 parts by mass and 80 parts by mass of the modified conjugated diene polymer of this embodiment. If the proportion of the modified conjugated diene polymer of this embodiment contained in the rubber component is within the above range, the rubber composition tends to have better vulcanizate abrasion resistance and lower hysteresis loss.

[0241] From the viewpoint of further improving the processability of the rubber composition of this embodiment, in addition to the rubber components, a rubber softener may also be added. As a rubber softener, the same type as those exemplified as those included in the above-mentioned modified conjugated diene polymers can be used, but mineral oil, or liquid or low molecular weight synthetic softeners are more suitable. Mineral oil-based rubber softeners, used to soften, compatibilize, and improve the processability of rubber components, and referred to as processing oils or filler oils, are mixtures of aromatic rings, cycloalkane rings, and paraffin chains. Specifically, those belonging to paraffin chains with a carbon number of 50% or more of the total carbon number are called paraffinic; those belonging to cycloalkane rings with a carbon number of 30% to 45% of the total carbon number are called cycloalkane; and those belonging to aromatic rings with a carbon number of more than 30% of the total carbon number are called aromatic. The rubber composition using the modified conjugated diene polymer of this embodiment preferably includes a rubber softener with a suitable aromatic content. By including such a rubber softener, the compatibility with the modified conjugated diene polymer is further improved. The content of rubber softener in the rubber composition of the modified conjugated diene polymer using this embodiment is expressed as the amount of rubber softener pre-added to the modified conjugated diene polymer or rubber-like polymer and the total amount of rubber softener added when the rubber composition is made. In the rubber composition using the modified conjugated diene polymer of this embodiment, the content of the rubber softener relative to 100 parts by weight of the rubber component is preferably 0 parts by weight or more and 100 parts by weight or less, more preferably 10 parts by weight or more and 90 parts by weight or less, and even more preferably 30 parts by weight or more and 90 parts by weight or less. By keeping the content of the rubber softener relative to 100 parts by weight of the rubber component at 100 parts by weight or less, exudation can be suppressed, and the stickiness of the rubber composition surface can be further suppressed.

[0242] Rubber compositions can be manufactured by mixing modified conjugated diene polymers, rubbery polymers, fillers, silane coupling agents, and rubber softeners. There are no particular limitations on the mixing method; examples include melt mixing using conventional mixers such as open rollers, Bamboo mixers, kneaders, single-screw extruders, twin-screw extruders, or multi-screw extruders; and methods involving dissolving and mixing the components, followed by removing the solvent by heating. Of these methods, melt mixing using rollers, Bamboo mixers, kneaders, or extruders is preferred from the viewpoint of productivity and good mixing properties. Furthermore, the rubber components can be mixed with fillers, silane coupling agents, and additives in a single process, or they can be mixed in multiple stages.

[0243] The rubber composition of the modified conjugated diene polymer using this embodiment can be vulcanized using a vulcanizing agent to produce a sulfide. There are no particular limitations on the vulcanizing agent; examples include: free 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 polysulfide compounds.

[0244] In the rubber composition using the modified conjugated diene polymer of this embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, more preferably 0.1 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the rubber component. As the vulcanization method, previously known methods can be used. Furthermore, as the vulcanization temperature, it is preferably 120°C or more and 200°C or less, more preferably 140°C or more and 180°C or less.

[0245] When vulcanizing the rubber composition, vulcanization accelerators and / or vulcanization aids may be used as needed. As vulcanization accelerators, previously known materials may be used, such as: sulfinamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-amine-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators, but not limited to the above. Furthermore, zinc oxide and stearic acid can be cited as examples of vulcanizing aids, but are not limited to these. Relative to 100 parts by weight of rubber, the content of vulcanization accelerator and vulcanization aid is preferably 0.01 parts by weight and 20 parts by weight, and more preferably 0.1 parts by weight and 15 parts by weight.

[0246] In the rubber composition using the modified conjugated diene polymer of this embodiment, various additives other than those described above, such as softeners and other fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, can be used within a range that does not impair the effects of this embodiment. Known softeners can be used as softeners. Examples of other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate, but the list is not limited to these. Known materials can be used as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants.

[0247] The rubber composition using the modified conjugated diene polymer of this embodiment can be suitably used as a tire rubber composition. The rubber composition of this embodiment is not particularly limited, and can be suitably used for various tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless anti-skid tires; and for various parts of the tire such as the tread, carcass, sidewall, and bead.

[0248] Furthermore, unless otherwise specified, the numerical ranges described above as preferred ranges can be replaced by any combination of the values ​​described as upper limits and the values ​​described as lower limits. [Example]

[0249] The present invention will be described in more detail below with specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

[0250] The various physical properties in the examples and comparative examples were measured by the methods shown below.

[0251] ((Physical Property 1) Conversion Rate) (Amount of solid matter) The amount of solids in the modified conjugated diene polymer solution is determined based on the amount of non-volatile components in the solution flowing through the measuring point per unit time. The total amount of modified conjugated diene polymer solution flowing through the measuring point is collected over 3 minutes, and a polymerization terminator is added immediately. Subsequently, the solution is transferred to a heat-resistant dish and dried in an oven at 140°C for at least 30 minutes. The mass (M) of the remaining solids at this point is then measured. Here, the amount of solids (m) is calculated using the following formula (I).

[0252] [Number 7]

[0253] Furthermore, the measurement points are set as the discharge section of the polymerization step (P1) for synthesizing the first polymer chain segment and the discharge section of the polymerization step (P2) for forming the second polymer chain segment, and the solid content in these steps is set as m1 and m2, respectively. The conversion rates of the conjugated diene compound (cbd) and the conversion rates of the aromatic vinyl compounds (cst) in the polymerization step (P1) of synthesizing the first polymer segment are determined using the following formulas (II) and (III), respectively. Furthermore, in this embodiment, U1 is the mass of 1,3-butadiene added in the first unit per unit time, and V1 is the mass of styrene added in the first unit per unit time. In the following formula, X1 represents the amount of bonded styrene in the first polymer segment. Also, X2 represents the amount of bonded styrene in the second polymer segment.

[0254] [Number 8]

[0255] The conversion rate c in the polymerization step (P1) for synthesizing the first polymer segment is determined using the following formula (IV). Furthermore, in this embodiment, U1 is the mass of 1,3-butadiene added in the first unit per unit time, and V1 is the mass of styrene added in the first unit per unit time.

[0256] [Number 9]

[0257] ((Physical Property 2) Polymer Segment Ratio) In this embodiment, the polymer segment polymerized in the polymerization step (P1) before the monomer addition step is designated as the first polymer segment, and the polymer segment polymerized in the subsequent polymerization step (P2) is designated as the second polymer segment.

[0258] (The mass ratio of the first polymer segment to the second polymer segment, r1 and r2) The mass ratios r of the first polymer segment and the second polymer segment are shown in the following formulas (V) and (VI), respectively, and are calculated by the sum of the solid amounts m1 and m2 of each discharge portion in the polymerization step (P1) for synthesizing the first polymer segment and the polymerization step (P2) for forming the second polymer segment, relative to the mass (U) of the conjugated diene compound added per unit time in the entire polymerization step and the mass (V) of the aromatic vinyl compound. In this embodiment, U is the total amount of 1,3-butadiene added in the first unit and the second unit per unit time, and V is the total amount of styrene added in the first unit and the second unit per unit time.

[0259] [Number 10]

[0260] (Ratio of the mass ratio of polymer chain segments) The mass ratio R of polymer chain segments (=r1 / r2) is obtained using the following formula (VII).

[0261] [Number 11]

[0262] ((Property 3) Unit weight of bonded aromatic vinyl monomers (bonded styrene content)) (Styrene bonding amount Xall in conjugated diene polymers) A conjugated diene polymer collected from the discharge section of the polymerization step (P2) which does not contain rubber softener was used as a sample. 100 mg of the sample was diluted to 100 mL with chloroform and used as the test sample. The amount of bonded styrene (mass%) relative to 100% mass of the coupled conjugated diene polymer used as the sample was determined based on the absorption at the ultraviolet absorption wavelength (around 254 nm) caused by the phenyl group of styrene (measuring apparatus: Shimadzu UV-2450 spectrophotometer).

[0263] (Amount of styrene bonded in the first polymer segment x 1) The solids composition of the polymer solution in the discharge section of the polymerization step (P1) where the sample is transformed from a conjugated diene polymer into the polymer of the first polymer segment is determined. Regarding other conditions, the amount of bonded styrene is calculated using the same method as for the amount of bonded styrene in the conjugated diene polymer segment.

[0264] (Amount of styrene in the second polymer segment x 2) Based on the polymer segment ratios r1 and r2, and the amounts of bonded styrene X1 and Xall in the polymerization steps (P1) for synthesizing the first polymer segment and (P2) for forming the second polymer segment, respectively, the amount of bonded styrene (X2) in the second polymer segment is calculated using the following formula (VIII).

[0265] [Number 12] Formula (VIII)

[0266] (Difference in styrene content between polymer segment 1 and polymer segment 2 |X2-X1|) To evaluate the randomness of styrene, the difference in the amount of styrene bonded between the first and second polymer segments is calculated using |X2-X1|.

[0267] ((Property 4) The amount of vinyl bonds in bonded conjugated dienes (the amount of 1,2-vinyl bonds in bonded butadiene)) (Vinyl bond quantity of conjugated diene polymers) A conjugated diene polymer, which does not contain rubber softener and is collected from the discharge section of the polymerization step (P2) that forms the second polymer chain segment, is used as a sample. 50 mg of the sample is dissolved in 10 mL of carbon disulfide and used as the test sample. The infrared spectra of each sample were measured in the range of 600 to 1000 cm⁻¹ using a Fourier transform infrared spectrophotometer (manufactured by Nippon Spectrophotometer Co., Ltd., trade name "FT-IR230"). The amount of 1,2-vinyl bonds in bonded butadiene is determined (mol%) by the absorbance at a specified wavenumber, according to Hampton’s method (RR Hampton, Analytical Chemistry 21, 923 (1949)).

[0268] (Number of vinyl bonds Y1 in the first polymer segment) The sample was analyzed as the solids composition of the polymer solution discharged from the polymerization step (P1) in which the conjugated diene polymer was transformed into the polymeric polymer of the first polymer segment. The vinyl bond content was calculated using the same method as for the conjugated diene polymer, for other conditions.

[0269] (The amount of vinyl bonds Y2 in the second polymer segment) Based on the solid content m1, m2 and the vinyl bond content Y1, Yall in the bonded conjugated diene in the polymerization step (P1) for synthesizing the first polymer segment and the polymerization step (P2) for forming the second polymer segment, respectively, the vinyl bond content in the second polymer segment is calculated by the following formula (IX).

[0270] [Number 13] Formula (IX)

[0271] [Number 14] Formula(X)

[0272] ((Property 5) Estimated glass transition temperature, difference between estimated glass transition temperatures) Use equation (iii) to determine the estimated glass transition temperatures (estimated Tg1, estimated Tg2, estimated Tg) of the first polymer segment, the second polymer segment, and the modified conjugated diene polymer, respectively. When determining estimated Tg1 and estimated Tg2, simply replace Xall and Yall of the microstructure with X1, Y1 and X2, Y2, respectively.

[0273] [Number 15]

[0274] Furthermore, the difference in estimated glass transfer temperature can be obtained using the following formula (XI).

[0275] [Number 16]

[0276] (Physical Property 6) Molecular Weight The modified conjugated diene polymers of the examples and comparative examples were used as samples. A GPC measuring device (manufactured by Tosoh Corporation, trade name "HLC-8320GPC") with three columns filled with polystyrene gel was used to measure the chromatograms using an RI detector (manufactured by Tosoh Corporation, trade name "HLC8020"). The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined based on the calibration curve obtained using standard polystyrene. The dissolution solution used was THF (tetrahydrofuran) containing 5 mmol / L triethylamine. The column consisted of three Tosoh-manufactured "TSKgel SuperMultiporeHZ-H" tubing, with a Tosoh-manufactured "TSKguardcolumn SuperMP(HZ)-H" tubing connected to the front end as a guard column. The test sample was dissolved in 10 mL of THF to prepare the test solution. 10 μL of the test solution was injected into the GPC test device and the test was performed at an oven temperature of 40 °C and a THF flow rate of 0.35 mL / min.

[0277] (Physical Property 7) Modification Rate The modification rate in the modified conjugated diene polymers of the examples and comparative examples was determined by column adsorption GPC method as described below. The modified conjugated diene polymer was used as the sample, and the characteristics of the modified alkaline polymer component adsorbed on the GPC column with silicon dioxide gel as the filler were utilized for determination. For a sample solution containing the sample and a low molecular weight internal standard polystyrene, the amount of adsorption to the silicon dioxide column is determined by the difference between the chromatogram measured by the polystyrene column and the chromatogram measured by the silicon dioxide column, and the modification rate is calculated. <Preparation of Sample Solution>: Dissolve 10 mg of the sample and 5 mg of standard polystyrene in 20 mL of THF (tetrahydrofuran) to prepare the sample solution. <GPC Determination Conditions Using Polystyrene-Based Columns>: Using the Tosoh HLC-8320GPC, a product manufactured by Tosoh, and THF containing 5 mmol / L triethylamine as the dissociation solution, 10 μL of the sample solution was injected into the device. The chromatography chromatogram was obtained using an RI detector under the conditions of column oven temperature of 40°C and THF flow rate of 0.35 mL / min. The tubing is connected to three Tosoh-manufactured tubes under the trade name "TSKgel SuperMultiporeHZ-H", and a Tosoh-manufactured tube under the trade name "TSKguardcolumn SuperMP(HZ)-H" is connected to its front end as a protective tubing. <GPC Determination Conditions Using Silicon Dioxide-Based Columns> GPC measurements were performed using the Tosoh HLC-8320GPC and the RI detector (Tosoh HLC8020). Using THF as the dissolution solution, 50 μL of the sample solution was injected into the device, and the chromatography chromatogram was obtained under the conditions of column oven temperature of 40℃ and THF flow rate of 0.5 ml / min. The tubing is connected in sequence to Agilent's Zorbax PSM-1000S, PSM-300S, and PSM-60S, and is connected in front of it to a DIOL 4.6×12.5 mm 5 micron tubing as a protective tubing. <Calculation Method of Improvement Rate>: Set the peak area of ​​the chromatogram using a polystyrene-based column to 100, the peak area of ​​the sample to p1, and the peak area of ​​the standard polystyrene to p2. Set the peak area of ​​the chromatogram using a silicon dioxide-based column to 100, the peak area of ​​the sample to p3, and the peak area of ​​the standard polystyrene to p4. Calculate the modification rate (%) according to the following formula. Improvement rate (%) = [1 - (p2 × p3) / (p1 × p4)] × 100 (Where, p1 + p2 = p3 + p4 = 100)

[0278] (Property 8) Branching Degree (Bn) The branching degree (Bn) of modified conjugated diene polymers was determined by the GPC-light scattering method with an adhesion detector, as described below. The modified conjugated diene polymer was used as the sample, and a GPC measuring device (manufactured by Malvern, trade name "GPCmax VE-2001") was used, which was connected to three columns with polystyrene gel as filler. The measurements were performed using three detectors connected in sequence: a light scattering detector, an RI detector, and a viscosity detector (manufactured by Malvern, trade name "TDA305"). Based on standard polystyrene, the absolute molecular weight was determined from the results of the light scattering detector and the RI detector, and the intrinsic viscosity was determined from the results of the RI detector and the viscosity detector. For linear polymer systems, the shrinkage factor (g') is calculated as the ratio of the intrinsic viscosity to the intrinsic viscosity of each molecular weight, based on the intrinsic viscosity [η0] = 10⁻³.498M⁰.711. In the above formula, M is the absolute molecular weight. The dissociation solution used was THF containing 5 mmol / L triethylamine. The tubing is used to connect to Tosoh's product lines under the trade names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL". The test sample (20 mg) was dissolved in 10 mL of THF to prepare the test solution. 100 μL of the test solution was injected into the GPC test apparatus and the test was performed at an oven temperature of 40 °C and a THF flow rate of 1 mL / min. The absolute molecular weight distribution curve and branching distribution curve of the modified conjugated diene polymer were obtained by the above determination, and the branching degree (Bn) was calculated using the shrinkage factor (g'), which is defined as g'=6Bn / {(Bn+1)(Bn+2)}.

[0279] (Property 9) Height of tanδ peak The height of the tanδ peak was determined using ARES (Advanced Rheometric Expansion System) through dynamic viscoelastic analysis, as described below. 3 g of the modified conjugated diene polymer was dissolved in 30 mL of tetrahydrofuran, followed by the addition of methanol to the solution. The precipitate was then completely dried using a vacuum dryer at 40 °C. The dried polymer was then pressed at 120 °C for 3 minutes to form a sheet with a thickness of 1 mm, which was then punched into a circle with a diameter of 10 mm to prepare the test sample. Using a dynamic mechanical analyzer (TA Instruments, ARES-G2), in torsion mode, the tanδ corresponding to the temperature range of -100℃ to 100℃ was measured at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5℃ / min. The results are plotted with temperature on the horizontal axis and tanδ on the vertical axis, with the tanδ value at its maximum point set as the height of the tanδ peak.

[0280] ((Physical Property 10) Murney Viscosity of Polymer) The modified conjugated diene polymers of the examples and comparative examples were used as samples. The Munich viscosity was measured using a Munich viscometer (manufactured by Uejima Manufacturing Co., Ltd., trade name "VR1132"), according to ISO 289, using an L-shaped rotor, with the measurement temperature set to 100°C. First, the sample was preheated at the test temperature for 1 minute, and then the rotor was rotated at 2 rpm. The torque was measured after 4 minutes and set as the Munich viscosity (ML(1+4)).

[0281] [Manufacturing of Modified Conjugated Diene Polymers] (Example 1) Two trough-shaped pressure vessels are connected as a polymerization reactor. The internal volume of the trough-shaped pressure vessel is 10 L, and the ratio of its internal height (L) to diameter (D) (L / D) is 4.0. It has an inlet at the bottom and an outlet at the top, and has a jacket for agitator as a trough-shaped reactor with a stirrer and for temperature control. Pre-dehydrated 1,3-butadiene was mixed at 17.4 g / min, styrene at 5.8 g / min, and n-hexane at 180.1 g / min to obtain a mixed solution. In a static mixer located midway between the inlet pipe supplying this mixed solution to the reactant, n-butyllithium for residual impurity inert treatment was added at 0.104 mmol / min, and after mixing, continuously supplied to the bottom of the reactant. Then, 2,2-bis(2-tetrahydrofuranyl)propane (a polar substance) and n-butyllithium (a polymerization initiator) were supplied to the bottom of the first reactor, which was being vigorously mixed using a stirrer, at a rate of 0.034 mmol / min, while the reactor temperature was maintained at 82°C. When the polymerization reaction stabilized, a small amount of the conjugated diene polymer was withdrawn from the top of the reactor, and an antioxidant (BHT) was added at a rate of 0.2 g per 100 g of polymer. The solvent was then removed, and the amount of bonded aromatic vinyl groups (X1) in the first polymer chain segment, the amount of bonded vinyl groups (Y1) in the bonded conjugated diene, the conversion rate c, and the styrene conversion rate cst were determined.

[0282] Next, while continuously supplying polymer solution from the top of the first reactor to the bottom of the second reactor, 1,3-butadiene, styrene, n-hexane, 2,2-bis(2-tetrahydrofuranyl)propane (as a polar substance), and trimethoxy(4-vinylphenyl)silane (as a branching agent) are added to the connecting piping section (equivalent to the monomer addition section) at a rate of 7.5 g / min, respectively, at a rate of 2.6 g / min, at a rate of 42.9 g / min, at a rate of 0.062 mmol / min, respectively, at a rate of 0.025 mmol / min, respectively, are stirred and the reaction continues at 85°C.

[0283] Next, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (coupling modifier A in the table) was continuously added to the polymer solution flowing out from the top of the second reactor at a rate of 0.028 mmol / min as a coupling modifier, and the mixture was mixed using a static mixer to carry out the coupling reaction.

[0284] Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at a rate of 0.055 g / min (n-hexane solution) at a rate of 0.2 g per 100 g of polymer to terminate the coupling reaction. Subsequently, 25 phr of S-RAE oil (manufactured by JX Nippon Minerals Energy Co., Ltd., trade name "Process NC140") was added as a plasticizer and mixed using a mixer. The modified conjugated diene polymer (A1) was obtained by removing the solvent through steam stripping, and then used to determine various physical properties.

[0285] (Example 2) Except for changing the 1,3-butadiene supplied to the first reactor to 16.7 g / min, the styrene to 5.3 g / min, and the n-hexane to 176.2 g / min, changing the 1,3-butadiene added to the second reactor to 9.8 g / min, the styrene to 1.5 g / min, the n-hexane to 46.9 g / min, the polar substance to 0.255 mmol / min, changing the polymerization temperature of the second reactor to 78°C, and changing the amount of coupling modifier added to 0.018 mmol / min, the modified conjugated diene polymer of Example 2 was obtained in the same manner as in Example 1.

[0286] (Example 3) Except for changing the amount of coupling modifier added to 0.028 mmol / min, the modified conjugated diene polymer of Example 3 was obtained in the same manner as in Example 2.

[0287] (Example 4) Except for changing the 1,3-butadiene supplied to the first reactor to 17.2 g / min, the styrene to 5.4 g / min, the 1,3-butadiene added to the second reactor to 7.4 g / min, the styrene to 3.3 g / min, the n-hexane to 43.0 g / min, and the polar substance to 0.119 mmol / min, the modified conjugated diene polymer of Example 4 was obtained in the same manner as in Example 1.

[0288] (Example 5) Except that the branching agent added to the second unit was changed to 0.012 mmol / min, the modified conjugated diene polymer of Example 5 was obtained in the same manner as in Example 4.

[0289] (Example 6) Except for changing the n-butyllithium supplied as a polymerization initiator in the first reactor to 0.167 mmol / min, changing the polar substance to 0.029 mmol / min, changing the polar substance added to the second reactor to 0.107 mmol / min, not adding a branching agent, and changing the coupling modifier to 0.023 mmol / min, the modified conjugated diene polymer of Example 6 was obtained in the same manner as in Example 4.

[0290] (Example 7) Except for changing the n-butyllithium supplied as a polymerization initiator in the first reactor to 0.229 mmol / min, the polar substance to 0.040 mmol / min, the polar substance added to the second reactor to 0.137 mmol / min, the branching agent to 0.036 mmol / min, and the coupling modifier to 0.027 mmol / min, the modified conjugated diene polymer of Example 7 was obtained in the same manner as in Example 4.

[0291] (Example 8) Except for changing the n-butyllithium supplied as a polymerization initiator in the first reactor to 0.177 mmol / min, the polar substance to 0.031 mmol / min, the polar substance added to the second reactor to 0.105 mmol / min, the branching agent to 0.023 mmol / min, and the coupling modifier to 0.025 mmol / min, the modified conjugated diene polymer of Example 8 was obtained in the same manner as in Example 4.

[0292] (Example 9) Except for changing the n-butyllithium supplied as a polymerization initiator in the first reactor to 0.167 mmol / min, the polar substance to 0.029 mmol / min, the polar substance added to the second reactor to 0.101 mmol / min, the branching agent to 0.022 mmol / min, and the coupling modifier to 0.023 mmol / min, the modified conjugated diene polymer of Example 9 was obtained in the same manner as in Example 4.

[0293] (Example 10) Except that the branching agent added to the second unit was changed to 0.033 mmol / min and the coupling modifier was changed to 0.024 mmol / min, the modified conjugated diene polymer of Example 10 was obtained in the same manner as in Example 4.

[0294] (Example 11) Except for changing the 1,3-butadiene supplied to the first reactor to 18.8 g / min, the styrene to 3.6 g / min, the n-hexane to 177.7 g / min, the 1,3-butadiene added to the second reactor to 10.1 g / min, the styrene to 0.9 g / min, the n-hexane to 45.4 g / min, and the polar substance to 0.255 mmol / min, the modified conjugated diene polymer of Example 11 was obtained in the same manner as in Example 1.

[0295] (Example 12) Except that the 1,3-butadiene supplied to the first reactor was changed to 17.4 g / min, the styrene was changed to 4.6 g / min, the polar substance was changed to 0.090 mmol / min, the styrene added to the second reactor was changed to 3.8 g / min, and the polar substance was changed to 0.081 mmol / min, the modified conjugated diene polymer of Example 12 was obtained in the same manner as in Example 1.

[0296] (Example 13) Except for changing the 1,3-butadiene supplied to the first reactor to 14.1 g / min, the styrene to 4.7 g / min, the n-hexane to 174.3 g / min, the polar substance to 0.118 mmol / min, the polymerization temperature of the second reactor to 78°C, the 1,3-butadiene added to the second reactor to 9.4 g / min, the styrene to 5.1 g / min, the n-hexane to 48.7 g / min, the polar substance to 0.172 mmol / min, and the polymerization temperature of the second reactor to 78°C, the modified conjugated diene polymer of Example 13 was obtained in the same manner as in Example 1.

[0297] (Example 14) Except for changing the 1,3-butadiene supplied to the first reactor to 17.7 g / min, the styrene to 6.5 g / min, the n-hexane to 180.2 g / min, the 1,3-butadiene added to the second reactor to 7.6 g / min, the styrene to 1.6 g / min, the n-hexane to 42.8 g / min, and the polar substance to 0.128 mmol / min, the modified conjugated diene polymer of Example 14 was obtained in the same manner as in Example 1.

[0298] (Example 15) Except for changing the 1,3-butadiene supplied to the first reactor to 17.4 g / min, the styrene to 5.8 g / min, the n-hexane to 180.1 g / min, the 1,3-butadiene added to the second reactor to 7.5 g / min, the styrene to 2.6 g / min, the n-hexane to 42.9 g / min, and the polar substance to 0.121 mmol / min, the modified conjugated diene polymer of Example 15 was obtained in the same manner as in Example 1.

[0299] (Example 16) Except that no plasticizer was added, the modified conjugated diene polymer of Example 16 was obtained in the same manner as in Example 5.

[0300] (Example 17) Except for changing the 1,3-butadiene supplied to the first reactor to 15.6 g / min, the styrene to 4.7 g / min, the n-hexane to 173.1 g / min, the 1,3-butadiene added to the second reactor to 11.3 g / min, the styrene to 1.8 g / min, the n-hexane to 50.0 g / min, and the polar substance to 0.121 mmol / min, the modified conjugated diene polymer of Example 17 was obtained in the same manner as in Example 3.

[0301] (Comparative Example 1) Except for changing the 1,3-butadiene supplied to the first reactor to 17.8 g / min, the styrene to 8.0 g / min, the n-hexane to 180.3 g / min, the polar substance to 0.045 mmol / min, the reaction temperature of the first polymerization reactor to 65°C, and omitting the addition of styrene and polar substances in the second reactor, changing the 1,3-butadiene added to the second reactor to 7.6 g / min, the n-hexane to 42.8 g / min, and the reaction temperature of the second polymerization reactor to 90°C, the modified conjugated diene polymer of Comparative Example 1 was obtained in the same manner as in Example 1.

[0302] (Comparative Example 2) Except for changing the 1,3-butadiene supplied to the first reactor to 20.0 g / min, the styrene to 6.7 g / min, the n-hexane to 183.7 g / min, the polar substance to 0.033 mmol / min, the reaction temperature of the first polymerization reactor to 70°C, the 1,3-butadiene added to the second reactor to 6.7 g / min, the n-hexane to 39.4 g / min, and the reaction temperature of the second polymerization reactor to 90°C, the modified conjugated diene polymer of Comparative Example 2 was obtained in the same manner as Comparative Example 1.

[0303] (Comparative Example 3) The modified conjugated diene polymer of Comparative Example 3 was obtained by changing the n-butyllithium used as a polymerization initiator in the first reactor to 0.104 mmol / min, the polar substance to 0.025 mmol / min, and by not adding a branching agent in the second reactor and changing the coupling modifier to 0.016 mmol / min, in the same manner as Comparative Example 1.

[0304] (Comparative Example 4) Except that the amount of coupling modifier added was changed to 0.047 mmol / min, the modified conjugated diene polymer of Comparative Example 4 was obtained in the same manner as Comparative Example 1.

[0305] (Comparative Example 5) Except for changing the amount of n-butyllithium supplied as a polymerization initiator in the first reactor to 0.250 mmol / min, 1,3-butadiene to 19.8 g / min, styrene to 5.1 g / min, n-hexane to 146.7 g / min, and polar substances to 0.008 mmol / min, changing the reaction temperature of the first polymerization reactor to 60°C, changing the amount of 1,3-butadiene added to the second reactor to 8.5 g / min, n-hexane to 42.1 g / min, and polar substances to 0.109 mmol / min, omitting the branching agent, changing the reaction temperature of the second polymerization reactor to 60°C, and changing N,N-dimethyl-3-(trimethoxysilyl)propane-1-amine (coupling modifier B in the table) to 0.047 g / min, the addition of a branching agent is not performed. The modified conjugated diene polymer of Comparative Example 4 was obtained in the same manner as Comparative Example 1, except that mmol / min was used instead of A as the coupling modifier and no plasticizer was added.

[0306] (Comparative Example 6) Except for changing the polar substance supplied to the first reactor to 0.007 mmol / min, changing the reaction temperature of the first polymerization reactor to 60°C, changing the 1,3-butadiene added to the second reactor to 8.5 g / min, changing the branching agent to 0.025 mmol / min, changing the polar substance to 0.091 mmol / min, and changing A as the coupling modifier to 0.028 mmol / min, the modified conjugated diene polymer of Comparative Example 6 was obtained in the same manner as Comparative Example 4.

[0307] (Comparative Example 7) Except for changing the polar substance supplied to the first reactor to 0.016 mmol / min, changing the reaction temperature of the first polymerization reactor to 65°C, changing the polar substance added to the second reactor to 0.257 mmol / min, and changing the reaction temperature of the second polymerization reactor to 85°C, the modified conjugated diene polymer of Comparative Example 7 was obtained in the same manner as Comparative Example 6.

[0308] (Comparative Example 8) Except for changing the amount of n-butyllithium supplied as a polymerization initiator in the first reactor to 0.250 mmol / min, 1,3-butadiene to 18.4 g / min, styrene to 5.8 g / min, n-hexane to 146.3 g / min, and polar substances to 0.011 mmol / min, changing the reaction temperature of the first polymerization reactor to 60°C, changing the amount of 1,3-butadiene added to the second reactor to 10.2 g / min, n-hexane to 50.6 g / min, and polar substances to 0.109 mmol / min, without adding a branching agent, changing the reaction temperature of the second polymerization reactor to 60°C, and changing bis(3-(diethoxymethylsilylpropyl)-N-methylamine (coupling modifier C in the table) to 0.053 g / min, the addition of 1,3-butadiene to 18.4 g / min, styrene to 5.8 g / min, n-hexane to 146.3 g / min, and polar substances to 0.011 mmol / min, the addition of bis(3-butadiene to 18.4 g / min, styrene to 5.8 g / min, and polar substances to 0.109 mmol / min, the addition of bis(3-butadiene to 18.4 g / min, styrene to 5.8 ...), without adding a branching agent, changing the reaction temperature of the second polymerization reactor to 60°C, and changing bis(3-( The modified conjugated diene polymer of Comparative Example 8 was obtained in the same manner as Comparative Example 1, except that mmol / min was used instead of A as the coupling modifier and no plasticizer was added.

[0309] (Comparative Example 9) Batch polymerization was carried out in a 20 L tank-type polymerization reactor equipped with a stirring device in the following sequence. The internal atmosphere of the polymerization reactor was replaced with dry nitrogen, and 7.65 kg of hexane, 2.93 kg of cyclohexane, 240 g of 1,3-butadiene, 510 g of styrene, 8.8 mL of tetrahydrofuran, and 0.9 mL of ethylene glycol dibutyl ether were added to the reactor. Next, to detoxify impurities that could inactivate the polymerization initiator, a small amount of hexane solution containing n-butyllithium was added to the reactor as a scavenging agent. Subsequently, a hexane solution containing 3.12 mmol of BuLi was added to the reactor to initiate the polymerization reaction. The polymerization reaction was carried out for 4 hours and 10 minutes. During the polymerization reaction, the temperature inside the polymerization reactor was adjusted to 65°C, and the solution inside the polymerization reactor was stirred at a stirring speed of 100 rpm. Starting 20 minutes after the start of polymerization, 660 g of 1,3-butadiene and 90 g of styrene were continuously fed into the polymerization reactor for 3 hours and 20 minutes. Then, while maintaining the polymerization reactor temperature at 65°C, the obtained polymerization solution was stirred at a stirring speed of 100 rpm. 0.25 mmol of silicon tetrachloride was added to the polymerization solution, and the mixture was stirred for 15 minutes. Next, 5 mL of a hexane solution containing 0.8 mL of methanol was added to the polymerization reactor, and the polymerization solution was stirred for 5 minutes. Subsequently, 0.3 parts by mass of antioxidant (BHT) was added as a stabilizer for every 100 parts by mass of polymer to obtain the conjugated diene polymer of Comparative Example 9.

[0310] [Table 1]

[0311] [Table 2]

[0312] [Table 3]

[0313] [Table 4]

[0314] [Examples 18-34], [Comparative Examples 10-18] Using the modified conjugated diene polymers of the examples and comparative examples shown in Tables 1 to 4 above as raw material rubbers, rubber compositions containing each raw material rubber were obtained according to the following compositions. Modified conjugated diene polymers (Examples 1-17, Comparative Examples 1-9): 100 parts by weight (oil removed) Silicon dioxide (manufactured by Evonik Degussa, trade name "Ultrasil 7000GR", nitrogen adsorption specific surface area 170 m2 / g): 85.0 parts by weight carbon black (Manufactured by Tokai Carbon, product name "Seast7HM(N234)"): 2.0 parts by weight Silane coupling agent (manufactured by Evonik Degussa, trade name "Si69", bis(triethoxysilylpropyl)tetrasulfide): 6.8 parts by weight S-RAE oil (Manufactured by JX Nippon Minerals & Energy Co., Ltd., product name "Process NC140"): 40 parts by weight Zinc white: 2.4 parts by weight Stearic acid: 1.25 parts by weight Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 3.5 parts by weight Sulfur: 1.0 parts by weight Vulcanization Accelerator 1 Tetrabenzylthiuram disulfide: 0.5 parts by weight Vulcanization Accelerator 2 N-(tert-butyl)-2-benzothiazolium sulfinamide: 2.5 parts by weight Total: 246.95 parts by weight

[0315] A rubber composition is obtained by mixing the above materials using the following method. Using a closed mixer (0.3 L capacity) equipped with a temperature control device as the first stage of mixing, the raw rubber, fillers (silica, carbon black), silane coupling agent, processing oil, zinc white and stearic acid are mixed under the conditions of 65% filling rate and rotor speed of 30~50 rpm. At this point, the temperature of the closed mixer is controlled to obtain various rubber compositions (formulations) at an outlet temperature of 145~150℃.

[0316] Secondly, as the second stage of mixing, the obtained formulation is cooled to room temperature, an anti-aging agent is added, and mixing is performed again to improve the dispersion of silicon dioxide. In this case, the discharge temperature of the formulation is also adjusted to 120°C by controlling the temperature of the mixer. After cooling, as the third stage of mixing, sulfur and vulcanization accelerators 1 and 2 are added and mixed using an open drum set to 70°C. Subsequently, it is molded and vulcanized at 160°C for 20 minutes using a vulcanizing press. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, the evaluation is conducted using the following methods.

[0317] [Evaluation 1, Evaluation 2: Viscoelastic parameters] The viscoelastic parameters were determined in torsion mode using the ARES viscoelastic testing machine manufactured by Rheometrics Scientific. Each measured value was indexed by setting the result relative to the rubber composition of Comparative Example 10 to 100.

[0318] (Evaluation 1: Fuel-saving performance) The tanδ value, measured at 50°C with a frequency of 10 Hz and a strain of 1%, is used as an indicator of fuel-saving performance. A higher index indicates better fuel-saving performance. When the index value is above 85, it is judged that the sulfide has good fuel-saving performance.

[0319] (Evaluation 2: Wetland grip performance) The tanδ value, measured at 0℃ with a frequency of 10 Hz and a strain of 1%, is used as an indicator of wetland gripping performance. A higher index indicates better wetland gripping performance. When the index value is above 90, it is judged that the sulfide has good fuel-saving performance.

[0320] [Evaluation 3: Abrasion Resistance] Using an Akron abrasion tester (manufactured by Yasuda Seiki Co., Ltd.), the abrasion amount was measured under a load of 44.4 N and 1000 revolutions according to JIS K6264-2. The result of Comparative Example 10 was set to 100 and indexed. The higher the index, the better the wear resistance.

[0321] [Evaluation 4: Tensile Properties] Tensile strength and elongation were measured according to the tensile test method of JIS K6251. The product of these values ​​was indexed by setting the result of Comparative Example 10 to 100. A higher index indicates better tensile strength and tensile elongation (breaking strength). When the index value is above 85, it is judged that the sulfide has sufficient tensile properties.

[0322] [Rating 5: Processability] Regarding the unvulcanized modified conjugated diene polymers manufactured by the methods shown in the Examples and Comparative Examples, the cohesiveness (shape) immediately after discharge from the pressure kneader (immediately after discharge from the pressure kneader during the first stage of mixing) was visually observed, and each functional inspector evaluated them based on the following criteria with a maximum score of 5. Cohesiveness is an indicator of the processability of sulfides. The higher the index, the better the processability. <Evaluation Criteria> 1: The edge portion of the sheet is less than 50% smooth, resulting in very poor processability. 2: The edges of the sheet material are smoother than 50% but less than 60%, resulting in poor processability. 3: The edges of the sheet are smoother than 60% but less than 80%, and have good processability. 4: The edges of the sheet are smoother than 80% but less than 90% of the surface, resulting in excellent processability. 5: Over 90% of the edges of the sheet are relatively smooth, resulting in excellent processability.

[0323] Compared with Comparative Examples 10-18, Examples 18-34 confirmed that when made into sulfides, they exhibited an excellent balance of fuel-saving performance, wet grip performance, abrasion resistance, and tensile properties.

[0324] [Table 5] Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 The modified conjugated diene polymer used Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 (Evaluation 1) Fuel-saving performance 98 98 98 98 94 92 (Evaluation 2) Wetland grip performance 110 110 110 125 125 118 (Evaluation 3) Abrasion resistance 100 100 100 100 97 93 (Evaluation 4) Tensile properties 100 95 95 100 102 102 (Evaluation 5) Processability 4 4 4 4 4 2

[0325] [Table 6] Example 24 Example 25 Example 26 Example 27 Example 28 The modified conjugated diene polymer used Example 7 Example 8 Example 9 Example 10 Example 11 (Evaluation 1) Fuel-saving performance 102 98 98 105 108 (Evaluation 2) Wetland grip performance 125 125 125 125 95 (Evaluation 3) Abrasion resistance 100 102 105 108 115 (Evaluation 4) Tensile properties 93 102 104 94 90 (Evaluation 5) Processability 5 4 3 2 4

[0326] [Table 7] Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 The modified conjugated diene polymer used Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 (Evaluation 1) Fuel-saving performance 92 88 98 98 94 97 (Evaluation 2) Wetland grip performance 140 155 104 140 121 118 (Evaluation 3) Abrasion resistance 85 70 100 100 97 98 (Evaluation 4) Tensile properties 100 105 100 92 102 93 (Evaluation 5) Processability 4 5 4 4 3 4

[0327] [Table 8] Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Comparative Example 15 Comparative Example 16 Comparative Example 17 Comparative Example 18 The modified conjugated diene polymer used Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 (Evaluation 1) Fuel-saving performance 100 110 93 83 80 110 108 81 43 (Evaluation 2) Wetland grip performance 100 85 93 125 105 105 110 98 286 (Evaluation 3) Abrasion resistance 100 115 93 90 120 120 115 120 66 (Evaluation 4) Tensile properties 100 90 102 90 80 82 84 82 65 (Evaluation 5) Processability 4 3 2 4 3 3 3 3 4

[0328] This application is based on Japanese Patent Application No. 2024-003559 filed with the Japan Patent Office on January 12, 2024, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0329] The modified conjugated diene polymer of this invention has industrial applicability as a material for applications such as tire treads, automotive interior / exterior parts, vibration-damping rubber, belts, footwear, foams, and various industrial products.

Claims

1. A modified conjugated diene polymer comprising conjugated diene monomer units and aromatic vinyl monomer units, having a weight-average molecular weight of 700,000 or more as determined by GPC, a modification rate of 60% or more, and exhibiting one tanδ peak in the temperature range of -100°C to 100°C in a tanδ peak diagram derived from dynamic viscoelastic analysis using an ARES (Advanced Rheometric Expansion System) based on the following <Condition 1>, with a height of 0.90 or more and 1.45 or less; <Condition 1> The tanδ peak diagram was obtained by measuring the polymer using a dynamic mechanical analyzer in torsion mode at a frequency of 10 Hz, a deformation rate (strain) of 0.5%, and a heating rate of 5°C / min.

2. The modified conjugated diene polymer of claim 1, wherein the branching degree (Bn) measured by GPC-light scattering method with a viscosity detector is 7 or more.

3. The modified conjugated diene polymer of claim 1 has a molecular weight distribution of 1.7 or higher and 2.5 or lower.

4. The modified conjugated diene polymer as claimed in claim 1, wherein the estimated glass transition temperature (estimated Tg) derived from the microstructure in the modified conjugated diene polymer is above -62°C and below -25°C.

5. The modified conjugated diene polymer of claim 1, having two or more polymer segments, and accounting for 10% or more of the mass fraction of the modified conjugated diene polymer, wherein the estimated glass transition temperature (estimated Tg) of the first polymer segment closest to the starting end is -90°C or more and -40°C or less, and the estimated Tg of the second polymer segment closest to the terminating end is -50°C or more and -10°C or less, and is greater than or equal to the estimated Tg of the first polymer segment, wherein the modifier is bonded to the end of the second polymer segment.

6. The modified conjugated diene polymer of claim 1, having modifier residues derived from alkoxysilane compounds having nitrogen atoms.

7. A method for manufacturing a modified conjugated diene polymer, which is a method for manufacturing a conjugated diene polymer as claimed in any one of claims 1 to 6, and includes a polymerization step: using a continuous reactor having two or more reactors connected in series, using a lithium compound as a polymerization initiator to polymerize at least one conjugated diene compound, wherein the continuous reactor has a monomer addition section, during which at least one conjugated diene compound and an aromatic vinyl compound are added; and the manufacturing method includes a coupling step: reacting the conjugated diene polymer obtained by the above polymerization step with a modifier having nitrogen atoms.

8. The method for manufacturing the modified conjugated diene polymer as claimed in claim 7, wherein in the above-mentioned polymerization step, an aromatic vinyl compound is used as the polymerization monomer, and the conversion rate of the aromatic vinyl compound in the polymerization intermediate in the monomer addition step is 70% or more.

9. The method for manufacturing the modified conjugated diene polymer as claimed in claim 7, wherein the monomer addition section is located between the piping of the first reactor and the second reactor in the continuous reactor.

10. The method for manufacturing the modified conjugated diene polymer as claimed in claim 7, wherein a branching agent is added to the monomer addition section.