TW202536002A - Modified conjugated diene polymer and method for producing modified conjugated diene polymer - Google Patents

Abstract

The modified conjugated diene polymer includes a conjugated diene monomer unit and an aromatic vinyl monomer unit, has a weight average molecular weight measured by GPC of 700,000 or more, has a modification rate of 60% or more, has one tan[delta] peak in a temperature range of -100 DEG C to 100 DEG C in a tan[delta] peak graph corresponding to temperatures derived from dynamic viscoelasticity analysis based on <Condition 1> by an ARES (Advanced Rheometric Expansion System), and has a height of the tan[delta] peak of from 0.90 to 1.45. <Condition 1> A tan[delta] peak graph is obtained by using a dynamic mechanical analyzer in torsional mode under conditions of a frequency of 10 Hz, a deformation rate (Strain) of 0.5%, and a temperature elevation rate of 5 DEG C/min.

Description

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

This invention relates to a modified conjugated diene polymer and a method for manufacturing the modified conjugated diene polymer.

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

As tire rubber materials designed to meet the requirements for improving the various properties described above, rubber compositions containing conjugated diene rubber polymers and reinforcing fillers such as carbon black and silica are known. In such rubber compositions, 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 the highly mobile conjugated diene polymer.

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, among these characteristics, an improvement in one tends to cause a deterioration in the other. Therefore, tire tread rubber is required to eliminate this inverse relationship.

Furthermore, in order to improve the abrasion resistance of rubber compounds, the industry has been actively trying to increase the content of cis-trans bonded conjugated dienes in the conjugated dienes used in rubber compounds. However, rubber compounds with a higher content of cis-trans bonded conjugated dienes have the problem of very poor processability.

On the other hand, from the perspective of tire durability, excellent tensile properties are also required for rubber compounds. 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 mutual affinity of these multiple rubber materials is low, there is a tendency to reduce the mechanical strength of the rubber compound. Therefore, a rubber compound that aims to eliminate the inverse relationship between wet grip and abrasion resistance and has excellent mechanical strength is needed.

For example, Patents 1-3 disclose a rubber composition containing a modified conjugated diene polymer and silica, 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. Furthermore, Patent 4 discloses a rubber composition containing a modified conjugated diene polymer with a low vinyl bond content. Moreover, Patent 5 discloses a rubber composition containing a conjugated diene polymer composition formulated with a plurality of modified conjugated diene polymers. [Prior Art Documents][Patent Documents]

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

[Problems to be Solved by the Invention] However, previously known rubber compounds, represented by those disclosed in Patents 1-4, still have room for improvement in their physical properties. For example, if a rubber compound 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 compounds are vulcanized, especially when vulcanized into compounds containing inorganic fillers such as silica, the following problems arise: the dispersibility of silica decreases, the flexibility deteriorates, performance on ice and snow decreases, and abrasion resistance is also insufficient.

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 wear resistance.

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 yield 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]

The inventors have conducted diligent research to solve the aforementioned problems and have discovered that a modified conjugated diene polymer can be provided, thus completing this invention. This modified conjugated diene polymer has a specified weight-average molecular weight and modification rate, and exhibits one peak within a specified temperature range in the tanδ peak diagram corresponding to temperature derived from dynamic viscoelasticity analysis. By setting the height of this tanδ peak within a specified numerical range, a rubber composition that simultaneously achieves excellent wet grip and abrasion resistance, as well as fuel efficiency and excellent tensile properties, can be obtained. In other words, this invention is as follows.

[1] A modified conyodene polymer comprising conyodene monomers and aromatic vinyl monomers, having a weight-average molecular weight of 700,000 or more as determined by GPC, and a modification rate of 60% or more, exhibits a tanδ peak in the temperature range of -100°C to 100°C in a tanδ peak diagram corresponding to temperature obtained by dynamic viscoelastic analysis performed using ARES (Advanced Rheometric Expansion System) based on the following <Condition 1>, 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 by measuring the properties of a tanδ polymer 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 described in [1] above, wherein the branching degree (Bn) measured by the GPC-light scattering method of the viscosity detector is 7 or more. [3] The modified conjugated diene polymer described in [1] or [2] above, wherein the molecular weight distribution is 1.7 or more and 2.5 or less. [4] The modified conjugated diene polymer described in any of [1] to [3] above, wherein the estimated glass transition temperature (estimated Tg) of the microstructure derived from the modified conjugated diene polymer is -62°C or more and less than -25°C. [5] The modified conjugated diene polymer described in any of [1] to [4] above has two or more polymer segments, and the mass fraction of the modified conjugated diene polymer is 10% or more, and the estimated glass transition temperature (estimated Tg) of the first polymer segment, which is the 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, which is the polymer segment closest to the ending end, is -50°C or more and -10°C or less, and is greater than the estimated Tg of the first polymer segment, and the modifier is bonded to the end of the second polymer segment. [6] The modified conjugated diene polymer described in any of [1] to [5] above has a modifier residue derived from an alkoxysilane compound having a nitrogen atom. [7] A method for manufacturing a modified conjugated diene polymer, which is a method for manufacturing a conjugated diene polymer as described in any of [1] to [6] above, 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, which adds at least one conjugated diene compound and an aromatic vinyl compound during the polymerization step; and the manufacturing method includes a coupling step: reacting the conjugated diene polymer obtained by the polymerization step with a modifier having nitrogen atoms. [8] The method for manufacturing a modified conjugated diene polymer as described in [7] above, wherein in the polymerization step, an aromatic vinyl compound is used as the polymerizing monomer, and the conversion rate of the aromatic vinyl compound in the polymerization intermediate in the monomer addition section is 70% or more. [9] The method for manufacturing a modified conjugated diene polymer 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 a modified conjugated diene polymer as described in any of [7] to [9] above, wherein a branching agent is added to the monomer addition section. [Effects of the Invention]

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.

The following describes in detail the forms used to implement the present invention (hereinafter referred to as "the embodiments"). The embodiments described below are illustrative of the present invention and are not intended to limit the present invention to the following. The present invention may be implemented with appropriate variations within the scope of its subject matter.

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

Regarding the modified conjugated diene polymer of this embodiment, the weight-average molecular weight, determined by GPC (gel permeation chromatography), is 700,000 or higher, and the modification rate is 60% or higher. In the tanδ peak diagram corresponding to temperature obtained from dynamic viscoelasticity analysis performed using ARES (Advanced Rheometric Expansion System) based on <Condition 1> below, there is one tanδ peak in the temperature range of -100℃ to 100℃, and the height of the tanδ peak is less than 1.45 and greater than 0.90. <Condition 1> The tanδ peak diagram is 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.

Based on the above composition, the 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.

(Conjugated Diene Compounds) The modified conjugated diene polymers of this embodiment comprise conjugated diene monomer units. Examples of conjugated diene compounds forming 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. Among these, 1,3-butadiene and isoprene are preferred from an industrially readily available perspective, and 1,3-butadiene is more particularly preferred. One or more of these compounds may be used individually or in combination.

(Aromatic Vinyl Compounds) The modified conjugated diene polymer of this embodiment comprises aromatic vinyl monomer units. Examples of aromatic vinyl compounds forming 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 more preferably styrene. One or more of these compounds may be used alone or in combination.

(Bound Aromatic Vinyl Monomer Unit Quantity X) The bound aromatic vinyl monomer unit quantity X (mass %) in this specification is the mass fraction (mass %) of the bound aromatic vinyl monomer unit relative to the total mass of the modified conjugated diene polymer or the following polymer chain segments.

Here, the amount of bonded aromatic vinyl monomer units 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 units"). Furthermore, the amount of bonded conjugated diene monomer units can also be determined based on the amount of bonded aromatic vinyl monomers obtained by the above method. Specifically, this can be measured using the method described in the following embodiments.

(Vinyl Bond Content Y in Bonded Conjugated Diene) The vinyl bond content Y (mol%) in bonded conjugated dienes in this specification is the molar fraction (mol%) of the 1,2-bonded unit relative to the polymeric unit derived from the conjugated diene contained in the modified conjugated diene polymer or the polymeric segment described below.

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 using Hampton's method (R. R. Hampton, Analytical Chemistry, 21, 923 (1949)) to determine the amount of vinyl bonds (1,2-bonds) in the bonded butadiene. Specifically, it can be determined by the method described in the following embodiments.

(Microstructure) The microstructure in this specification refers to the composition 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 of styrene and butadiene relative to the total mass of the modified conjugated diene polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

(Content of bonded aromatic vinyl monomer blocks) The modified conjugated diene polymer of this embodiment preferably has fewer or no bonded aromatic vinyl monomer blocks (hereinafter sometimes referred to as bonded aromatic vinyl monomer blocks) that link four or more bonded aromatic vinyl monomer blocks. By having fewer or no bonded aromatic vinyl monomer 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 blocks in the modified conjugated diene polymer can be determined by a known method, namely, by decomposing the modified conjugated diene polymer using Kolthoff's method (I. M. 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 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. By eliminating bonded aromatic vinyl monomer blocks in the modified conjugated diene copolymer and the polymer chains described below, the modified conjugated diene polymers tend to exhibit continuous properties in response to temperature changes. Therefore, there is a tendency to use sulfides of modified conjugated diene polymers that exhibit continuous changes over a wider temperature range and possess excellent tensile strength.

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

[Number 1]

In equation (1) above, the subscript i of the variables represents the components of the microstructure contained in the modified conjugated diene polymer, _Δαi is the difference in thermal expansion before and after glass transition of the homopolymer of component i, w _i is the mass ratio of component i in the modified conjugated diene polymer, Tg _i is the glass transition temperature of the homopolymer of component i, and ρ _i is the density of the homopolymer of component i. Reference values or measured values can be used. For example, when the modified conjugated diene polymer contains styrene, if one of i is set as the styrene component, Δαi = 3.6 × ^{10⁻⁴ K⁻¹} can be used based on the thermal expansion rate of polystyrene (J. BRANDRUP et al, Polymer Handbook, 3rd edition, (USA), John Wiley & Sons, Inc., 1966, VI-75), _Tgi = 105.3℃ can be used based on the measured value of the glass transition temperature, _{and ρi} = 1.02 g/ ^cm³ can be used based on the measured value of the density.

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 X _all (mass%), the amount of vinyl bonds in the bonded conjugated diene Y _all (mol%), and the thermal expansion coefficients (Δa i), glass transition temperature (Tg _i ), and density (ρ i) 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 ).

[Number 2]

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

[Number 3]

[Number 4]

That is, when the modified conjugated diene polymer of 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.

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 X _all (mass%) and the amount of vinyl bonds in the bonded conjugated diene Y _all (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 change in the amount of bonded aromatic vinyl monomer units X _all (mass%) and the amount of vinyl bonds in the bonded conjugated diene Y _all (mol%).

If the value of equation (1) above 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 equation (1) above is -60°C, the glass transition temperature of the modified conjugated diene polymer is estimated to be -60°C, and when equation (1) above is -40°C, the glass transition temperature is estimated to be -40°C.

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 estimated value (estimated Tg) of the glass transition temperature derived from the microstructure and based on 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 bonded aromatic vinyl monomer units between the polymer segments is 25% by mass or more, there is a significant tendency for the glass transition temperature (estimated Tg) estimated according to the above formula (1) to be 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 the value of formula (1) is more effective than adjusting the measured glass transition temperature of the modified conjugated diene polymer to a specific value. The reason is believed to be that DSC (Differential Scanning Calorimetry) captures smaller energy changes. Therefore, at the beginning of the easing of the low Tg portion in modified conjugated diene polymers, the overall glass transition temperature is raised, and the measured glass transition temperature is lower than the estimated glass transition temperature. For example, experiments have confirmed that even for modified conjugated diene polymers with the same microstructure throughout, the glass transition temperature measured by DSC can differ by about 2 to 5 °C due to the differences in the microstructure of each segment.

The lower limit of the estimated Tg value of the modified conjugated diene polymer of this embodiment, derived from the aforementioned microstructure, is preferably -62°C or higher, more preferably -58°C or higher, and even more preferably -55°C or higher. By having the estimated Tg value within the aforementioned range, the wet grip and tensile properties of the sulfide of the modified conjugated diene polymer of this embodiment tend to be improved. Furthermore, the upper limit of the estimated Tg value of the modified conjugated diene polymer of this embodiment, derived from the aforementioned microstructure, is preferably below -25°C, more preferably below -35°C, and even more preferably below -40°C. By having the upper limit value of the aforementioned formula (1) within the aforementioned range, the wear resistance and fuel-saving performance of the sulfide of the modified conjugated diene polymer of this embodiment tend to be improved. The above formula (1) can be controlled within the above value range by adjusting the microstructure of the bulk conjugated diene polymer. For example, in the case of butadiene-styrene copolymer, the amount of bonded styrene X all (mass%) and the amount of vinyl bonds Y all (mol%) in butadiene of the bulk conjugated diene polymer can be controlled within the above value range by adjusting the amount of bonded styrene X _all (mass%) and the amount of vinyl bonds Y _all (mol%) in butadiene according to the above formula (iii).

(Polymer Segments) The modified endothelial polymer of this embodiment preferably has two or more polymer segments. A polymer segment refers to a portion of a modified endothelial polymer containing endothelial monomer units and aromatic vinyl monomer units, or containing endothelial monomer units. Preferably, the polymer segment contains both endothelial monomer units and aromatic vinyl monomer units. Furthermore, in the modified endothelial polymer of this embodiment, it is preferable that the polymer segments are linked by four or more bonds, and the number of aromatic vinyl monomer units is small or non-existent. The plurality of polymer segments contained in the modified endothelial polymer of this embodiment have mutually distinct microstructures. The amount of bonded aromatic vinyl monomer units or the amount of bonded vinyl bonds in conjugated dienes may differ in each polymer chain segment, and each polymer chain segment may be distinguished by the method described in the following embodiments.

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 transition in a plurality of temperature ranges.

The aforementioned polymer segments are manufactured via continuous polymerization and are characterized by having a molecular weight distribution, unlike block structures typically produced by batch polymerization. Since a modified conjugated diene polymer contains multiple polymer segments, each with its own molecular weight distribution, each molecule exhibits a different glass transition temperature due to the overlap of these distributions. That is, depending on the combination of the different molecular weights of its multiple 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 if it were 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 if it were a low-glass-transition-temperature component. Therefore, the modified conjugated diene polymer of this embodiment has a continuous glass transition temperature distribution.

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.

In this specification, among the two or more polymer segments contained in a modified conjugated diene polymer, the polymer segment that accounts for 10% or more of the mass fraction of the modified conjugated diene polymer and is closest to the starting end is called the "first polymer segment," and the polymer segment 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 the conjugated diene compound, preferably the conjugated diene compound and the 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 include polymer segments, but from the viewpoint of ease of manufacture, it is preferable to include 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.

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 above -90°C, more preferably above -75°C, and even more preferably above -65°C. By ensuring the lower limit of the estimated Tg of the first polymer segment is within the above range, the wet grip and tensile properties of the sulfide of the modified conjugated diene polymer of this embodiment are likely to be improved. 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 aforementioned range, there is a tendency to improve the wear resistance and fuel-saving performance of the sulfides of the modified conjugated diene polymer of this embodiment. The estimated Tg can be controlled within the aforementioned range by adjusting the microstructure of the modified conjugated diene polymer. For example, in the case of butadiene-styrene polymers, the estimated Tg can be controlled within the aforementioned range by adjusting the amount of styrene _X1 (mass%) and the amount of vinyl bonds _Y1 (mol%) in the butadiene of the first polymer segment using the aforementioned formula (iii).

In the modified conjugated diene polymer of this embodiment, the estimated lower limit of the Tg of 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 the Tg of the second polymer segment within the above range, the wet grip and tensile properties of the sulfide of the modified conjugated diene polymer of this embodiment are likely to be improved. Furthermore, the estimated upper limit of the Tg of the second polymer segment is preferably -10°C or lower, more preferably -15°C or lower, and even more preferably -20°C or lower. Also, it is preferable that the estimated Tg of the second polymer segment is higher 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 segment. By ensuring that the estimated upper limit of Tg is within the aforementioned range, the abrasion resistance and fuel-saving performance of the sulfides of the modified conjugated diene polymers of this embodiment can be improved. The estimated Tg can be controlled within the aforementioned range by adjusting the microstructure of the modified conjugated diene polymer. For example, in the case of butadiene-styrene polymers, the estimated Tg can be controlled within the aforementioned range by adjusting the amount of bonded styrene _X2 (mass%) in the second polymer and the amount of vinyl bonds _Y2 (mol%) in the butadiene using formula (iii).

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. Furthermore, modified conjugated diene polymers can be obtained that exhibit a balance between suppressing the reduction in tensile strength and possessing excellent wet grip and abrasion resistance.

The greater the difference in estimated glass transition temperature between the first and second polymer chain segments (|estimated Tg ₂ - estimated Tg ₁ |), the slower the glass transition occurs over a wider temperature range. Therefore, there is a tendency for the height of the tanδ peak of modified conjugated diene polymers to decrease.

Polymer segments can also be defined in previously known continuously polymerized conjugated diene polymers, but the variation in glass transition temperature is presumed to be small, and rapid glass transition behavior is exhibited within a narrow temperature range. On the other hand, in the modified conjugated diene polymer of this embodiment, multiple polymer segments each have different glass transition temperatures, and as mentioned 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 and abrasion resistance.

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

(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 more slowly glass transition occurs 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 transition within a narrow temperature range, to decrease.

In the modified conjugated diene polymer of this embodiment, it is preferable that the first and second polymer segments have a defined mass ratio. The polymer segment mass ratio represents the average mass fraction of each polymer segment relative to the total mass of the modified conjugated diene polymer. The mass ratio of the first and second polymer segments of the modified conjugated diene polymer of this embodiment is defined as the mass ratio of the polymer segments obtained in each of steps P1 and P2, which are polymerization steps for 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 , 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 aforementioned polymer chain segments can be determined by the method described in the following embodiments. 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 steps of each polymer chain segment during the manufacturing process of the modified conjugated diene polymer of this embodiment.

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, the conjugated diene compound, aromatic vinyl compound, polar substance, and solvent are sequentially added to each reactor by continuous solution polymerization. The substances added sequentially may be the same or different in the reactors.

(tanδ peak height) Regarding the modified conjugated diene polymer of this embodiment, in the temperature-corresponding tanδ peak diagram derived by dynamic viscoelastic analysis 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 above 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 modified conjugated diene polymers, and has a high concentration of aromatic vinyl monomers and a high concentration of conjugated diene monomers undergoing vinyl bonding. It also has excellent wet grip properties, thus having the tendency to obtain sulfides that can suppress the reduction of tensile strength and have a good balance between wet grip and abrasion resistance.

In this manual, the "tanδ peak" refers to the peak that appears in the tanδ peak diagram corresponding to the temperature 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.

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, monomer concentration, or catalyst concentration during polymerization. Therefore, the tanδ peak of such random copolymers becomes higher and sharper. This is because, in most cases, aromatic ethylene monomers have higher randomness and always have a uniform microstructure. Such random copolymers can exhibit a significant inverse relationship between wet grip and abrasion resistance.

On the other hand, in the case of block copolymers produced by batch polymerization, the tanδ peak is significantly broadened, the tanδ peak height is reduced, or the tanδ peak tends 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. As a result, the tensile strength tends to be poor when producing sulfides.

The height of the tanδ peak indicates the degree of randomness in the microstructure within the molecule. By using tanδ peak heights above 0.90 and below 1.45, modified conjugated diene polymers can suppress the reduction of intramolecular compatibility and have high concentrations of aromatic vinyl monomers and high concentrations of vinyl-bonded conjugated diene monomers, as well as polymer segments with excellent wet grip properties. Thus, modified conjugated diene polymers can be obtained that suppress the reduction of tensile strength and have a good balance between wet grip and abrasion resistance.

To effectively 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 crucial to control the microstructure of the two polymer segments. Specifically, by increasing the difference in estimated Tg between the two polymer segments and bringing the ratio of their average molecular weights closer 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 for controlling the difference in estimated Tg between the two polymer segments, an example is the polymerization of aromatic vinyl monomers and vinyl-bonded conjugated diene monomers in a moderately random distribution. Specifically, the ratio of the average molecular weights of the two polymer segments can be controlled by adding conjugated diene compounds and aromatic vinyl compounds between the polymerization steps of the first and second polymer segments, and by adjusting the amounts of aromatic vinyl monomers, polar substances, and polymerization temperatures 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.

In continuous polymerization, to control the tanδ peak height within a specified range and to maintain the appropriate randomness of the aromatic vinyl monomer units and the vinyl-bonded conjugated diene 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, while reducing the amount of bonded aromatic vinyls and the amount of vinyl bonds in the bonded conjugated diene of the first polymer segment. Here, when the amount of polar substance or polymerization conditions such as polymerization temperature and polymerization concentration are set lower in order to reduce the amount of bonded aromatic vinyl groups in the first polymer chain and the amount of vinyl bonds in the bonded conjugated diene, the conversion rate of aromatic vinyl compounds 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 chain, 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 to have an aromatic vinyl compound conversion rate of 70% or higher at the discharge section of the first polymer segment polymerization step, and to immediately add the remaining conodediene compound and aromatic vinyl compound before the second polymer segment polymerization. Furthermore, as described below, the aromatic vinyl compound conversion rate is defined as the mass of aromatic vinyl compound consumed in the polymerization reaction to form the conodediene polymer relative to the total amount of aromatic vinyl compound added at the time of measurement.

(Glass transition temperature) The measured glass transition temperature (Tg) of the modified conjugated diene polymer of this embodiment is preferably above -62°C, more preferably above -58°C, and even more preferably above -55°C. 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 be even better. Furthermore, the modified conjugated diene polymer of this embodiment preferably has an estimated Tg value between -62°C and -25°C, calculated based on the microstructure. Modified conjugated diene polymers of this embodiment that satisfy this value range essentially have a measurable glass transition temperature within the aforementioned range. The glass transition temperature can be within any combination of the aforementioned upper and lower limits. The glass transition temperature of the modified conjugated diene polymer can be measured 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, the determination can be performed using the method described in the following embodiments. 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 using DSC.

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 conjugated diene. Specifically, increasing the amount of bonded aromatic vinyl monomer units and the amount of vinyl bonds in the conjugated diene increases the glass transition temperature, while decreasing these amounts decreases the glass transition temperature.

(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 above weight average molecular weight is preferably 150 × ^10⁴ or lower, more preferably 110 × ^10⁴ or lower, and even more preferably 100 × ^10⁴ or lower. If the above 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 aforementioned upper and lower limits. The weight-average molecular weight of the modified conjugated diene polymer can be determined by the GPC method, specifically by the method described in the following embodiments.

(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 above number average molecular weight is preferably 80 × ^10⁴ or lower, more preferably 70 × ^10⁴ or lower, and even more preferably 50 × ^10⁴ or lower. If the above number average molecular weight meets the above range, the dispersibility of the filler in the sulfide is better, and it tends to have excellent processability. The number average molecular weight can be within a range formed by any combination of the above upper and lower limits. The number average molecular weight of modified conjugated diene polymers can be determined by the GPC method, which can be performed by the method described in the following embodiments.

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.

(Molecular Weight Distribution) The molecular weight distribution of the modified conjugated diene polymer of 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 of 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 forming sulfides. The molecular weight distribution of the modified conjugated diene polymer of this embodiment is more preferably 1.8 or higher, and more preferably 2.0 or higher. Furthermore, as an upper limit, it is preferably 2.5 or lower, more preferably 2.2 or lower, and more preferably 2.1 or lower. The molecular weight distribution can fall within any combination of the above upper and lower limits.

(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. With the Munich viscosity of the modified conjugated diene polymer of this embodiment within the above range, there is a tendency to further improve the processability during vulcanization and the abrasion resistance of its sulfides. The Munich viscosity of the modified conjugated diene polymer can be measured by the method described in the following embodiments. The Munich viscosity of the modified conjugated diene polymer of this embodiment can be controlled within the above-mentioned value range by adjusting the amount of polymerization initiator, the type and amount of branching agent, the modifier, and the type and amount of plasticizer.

From the perspectives of fuel efficiency, processability, abrasion 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 using an adhesion detector (hereinafter also referred to as branching degree (Bn)), is preferably 7 or higher. Generally, 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, relative to the longest polymer backbone, there are actually 5 or more side chains.

Here, "branching" refers to a polymer chain formed by bonding one polymer chain to another. 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 on those side chains when they branch out. Therefore, when one polymer chain acts as a side chain bonded to the longest polymer chain, and another polymer chain is bonded to that side chain, the branching degree is 2.

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

Generally, branched polymers tend to have smaller molecular sizes when compared to linear polymers with the same absolute molecular weight. 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 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 degree of branching of the polymer is greater, its size is relatively smaller, and therefore the shrinkage factor (g') tends to decrease.

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 ]).

Furthermore, the intrinsic viscosity [ _η0 ] of linear polymers is known to be based on the relationship [ _η0 ] = ^{10⁻³.498 M⁰.711} . In this formula, M is the absolute molecular weight determined by the light scattering method described in the following embodiment. Therefore, by determining the absolute molecular weight and intrinsic viscosity of the target polymer using the GPC-light scattering method with an attached 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 the longest polymer backbone.

The calculated branching degree (Bn) is an indicator representing the branched structure of the modified conjugated diene polymer. 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 6 polymer chains are bonded to the longest highly branched backbone structure, and the branching degree (Bn) is evaluated as 6. The modified conjugated diene polymer of this embodiment preferably has a branching degree (Bn) of 7 or higher, but in this case, it means that the modified conjugated diene polymer has the same branching as a star polymer structure with 9 branches.

Here, "branching" is formed by one polymer being directly or indirectly bonded to other polymers. Also, "branching degree (Bn)" is the number of polymers that are directly or indirectly bonded to each other in the longest main chain structure.

With a branching degree (Bn) of 7 or higher, the modified conjugated diene polymer of this embodiment exhibits excellent processability when forming sulfides, and also demonstrates excellent fuel economy and abrasion resistance during sulfide formation. Typically, as the absolute molecular weight increases, processability tends to deteriorate. However, by having a branching degree (Bn) of 7 or higher, the viscosity increase during sulfide formation associated with the increase in absolute molecular weight is significantly suppressed. Therefore, by thoroughly mixing with silica, for example, during the mixing process, silica can be dispersed around the modified conjugated diene polymer. The result is that, for example, in modified conjugated diene polymers, by setting a larger molecular weight, abrasion resistance and breaking strength can be improved, and by sufficient mixing, silica can be dispersed around the polymer, and functional groups can function and/or react, thereby achieving practically sufficient fuel efficiency and wet grip.

Furthermore, in the modified conjugated diene polymer of this embodiment, where the tanδ peak height in the tanδ peak diagram corresponding to temperature, derived from the dynamic viscoelasticity analysis based on the above <Condition 1>, 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 exhibits superior fuel-saving performance and wet grip.

The branching degree (Bn) of the modified conjugated diene polymer of 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 forming sulfides.

Furthermore, there is no particular limitation on the upper limit of the branching degree (Bn) of the modified conjugated diene polymer of this embodiment. 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. With the modified conjugated diene polymer of this embodiment having a branching degree (Bn) of 84 or less, it tends to have excellent wear resistance and tensile properties when making sulfides.

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 method for manufacturing the modified conjugated diene polymer as described below, the branching degree can be controlled to be 7 or higher.

(Main Chain Branching Structure) To control the degree of branching mentioned above, 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 halogen, 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.

Furthermore, the branch points forming the main chain branch structure preferably have at least two polymer chains, more preferably have three or more non-main chain polymer chains, and even more preferably have four or more non-main chain polymer chains.

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

(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, further preferably 6 or more branches, and further preferably 8 or more branches.

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 star-shaped branch has a portion derived from a vinyl monomer containing alkoxysilyl or halogen, and the portion derived from the vinyl monomer containing alkoxysilyl or halogen further has a main chain branch structure. Regarding the method for obtaining the modified conjugated diene polymer with this structure, the aforementioned "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.

To obtain modified conjugated diene polymers, for example, the following method can be used: polymerization is carried out using an organolithium-based compound as a polymerization initiator; a branching agent imparting specific branching points is added during or after polymerization; and after further polymerization, a coupling agent imparting a specific branching ratio is used for modification. The aforementioned modified conjugated diene polymer has a star-shaped polymer structure with three or more branches, and at least one star-shaped branch has a portion originating from a vinyl monomer comprising alkoxysilyl or halogen, and the portion originating from the vinyl monomer comprising alkoxysilyl or halogen further has a main chain branching structure. Methods for controlling such polymerization conditions are described in the manufacturing method shown in the following embodiments.

(Detailed structure of the main chain branching structure) In the modified conjugated diene polymer of this embodiment, the portion derived from the vinyl monomer containing alkoxysilyl or halogen is based on the monomer unit of the compound represented by the following general formula (1) or (2), and preferably has a branching point of the polymer chain due to the monomer unit based on the compound represented by the following formula (1) or (2), more preferably is a modified conjugated diene polymer obtained 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, the coupling agent may also have the functions of the following modifier.

[Chemistry 1]

[Chemistry 2]

In formula (1), ^R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms or an aryl group having 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, which 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 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. When there are multiple ^R2 to ^R5 , ^R2 to ^R5 are independent. ^X2 to ^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.

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). Thereby, the number of branches is increased, which tends to improve wear resistance and processability.

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. In this way, there is a tendency to obtain the effect of improving wear resistance and processability.

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.

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, and n=3. This results in an increased modification rate and branching degree, which tends to improve fuel efficiency, wear resistance, and processability.

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 formula (1) or formula (2) below.

[Chemistry 3]

[Chemistry 4]

In formula (1), ^R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms or an aryl group having 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, which 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 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. When there are multiple ^R2 to ^R5 , ^R2 to ^R5 are independent. ^X2 to ^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.

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.

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

Furthermore, from the perspective 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 formula (1) above where ^R1 is a hydrogen atom, m=0, l=0, and n=3.

Furthermore, from the perspective 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) where m=0, l=0, n=3, a=0, b=0, c=3.

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.

For example, the following can be cited: 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.

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 Dimethylisopropoxy(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.

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.

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.

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, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene. 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-triisopropoxysilylphenyl)ethylene, 1,1-bis(2-trimethoxysilyl) 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.

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.

(Modification Rate) The modification rate of the modified endothelial polymer in this embodiment is 60% or more. In this specification, "modification rate" is expressed as a percentage (%). It refers to the mass percentage of modified endothelial polymer components with specific functional groups that have affinity or bonding reactivity with fillers relative to the total mass of the mixture, obtained by modifying the endothelial polymer using a nitrogen-containing modifier. Therefore, when the specific functional group contains nitrogen atoms, it represents the mass ratio of nitrogen-containing modified endothelial polymers relative to the total mass 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 a conjugated diene polymer containing modified conjugated diene polymer obtained by reacting a nitrogen-atom-containing modifier with the ends of the conjugated diene polymer is obtained, the mass ratio of the modified conjugated diene polymer with nitrogen-containing functional groups generated by the nitrogen-atom-containing modifier to the total amount of modified conjugated diene polymer is the modification rate.

The modified conjugated diene polymer of this embodiment is preferably modified at the end of the second polymer chain. By bonding with the filler at the end of the second polymer chain, which has a higher glass transition temperature, there is a tendency to obtain sulfides with better wet grip performance.

The modification rate can be determined by using a chromatographic method that separates the modified component containing functional groups from the unmodified component. An example of such a chromatographic method is the use of a gel osmosis chromatography column with a polar substance such as silica, which adsorbs specific functional groups, as a packing material. The internal standard of the unadsorbed component is used for comparison to quantify the modification rate. More specifically, the modification rate can be obtained by using a sample solution containing the sample and a low molecular weight internal standard, polystyrene, to determine the adsorption amount on a silica column based on the difference between the chromatogram obtained using a polystyrene-based gel column and the chromatogram obtained using a silica-based column. More specifically, the modification rate can be determined by the method described in the following embodiments.

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 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 monomers having at least one nitrogen atom in their molecule, and using a modifier with the following structural formula, while controlling the polymerization conditions.

From the perspective of the 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 even more preferably 70% or more.

<Nitrogen-containing modifiers> 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, epoxide compounds with nitrogen atoms, and alkoxysilane compounds with nitrogen atoms, but are not limited to the above.

As a modifier containing nitrogen atoms, it is preferred 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.

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

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, and 1,3,5-trivinyl-1,3,5-triazacyclohexane-2,4,6-trione, but are not limited to the above.

Examples of carbonyl compounds that act as nitrogen-containing modifiers include: 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidinone, N-methyl-2-quinolones, 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-dimethylmethylpyridylamine, N,N-dimethylisonicotinamide, etc., but not limited to the above.

Examples of vinyl compounds that serve as modifiers containing nitrogen atoms include: N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylcis-butenediimide, N-methylbenzyldimethylimide, N,N-bis(trimethylsilylacrylamide), α-linylacrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis(N,N-dimethylaniline), 4,4'-vinylidenebis(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.

Regarding epoxides that serve as modifiers containing nitrogen atoms, examples include hydrocarbons containing epoxy groups bonded to amine groups, but this is not a limitation; they may further contain epoxy groups bonded to ether groups. Examples of such epoxides include those represented by the following general formula (a), but this is not a limitation.

[Chemistry 5]

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., having oxygen polar groups; thioethers, thioketones, etc., having sulfur polar groups; tertiary amino groups, imine groups, etc., having nitrogen polar groups.

Divalent or higher hydrocarbons can be saturated or unsaturated linear, branched, or cyclic hydrocarbons, including alkyl, alkenyl, and phenyl groups. Preferably, they are hydrocarbons with 1 to 20 carbon atoms. Examples include: methylene, ethyl, butyl, cyclohexyl, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethyl)-cyclohexane, ortho-phenyl, m-phenyl, p-phenyl, m-xylene, p-xylene, bis(phenyl)-methane, etc.

In equation (a) above, ^R1 and ^R4 are hydrocarbons with 1 to 10 carbon atoms, and ^R1 and ^R4 can be the same or different from each other. In equation (a) above, ^R2 and ^R5 are hydrogen or hydrocarbons with 1 to 10 carbon atoms, and ^R2 and ^R5 can be the same or different from each other. In equation (a) above, ^R3 is a hydrocarbon with 1 to 10 carbon atoms, or the structure of equation (a1) below. ^R1 , ^R2 , and ^R3 can be a cyclic structure bonded to each other. Furthermore, when ^R3 is a hydrocarbon, it can also be a cyclic structure bonded to R. In the case of the above cyclic structure, it can be a form in which N bonded to ^R3 is directly bonded to R. 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.

[Chemistry 6]

In the above formula (a1), ^R1 and ^R2 have the same definition as ^R1 and ^R2 in the above formula (a). ^R1 and ^R2 can be the same or different from each other.

Regarding epoxy compounds that serve as modifiers containing nitrogen atoms, those containing epoxy groups are preferred, and those containing hydroglycerol groups are even more preferred.

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, compounds have epoxy-containing groups having glycidylamino or diglycidylamino and glycidoxy groups respectively; for example, compounds represented by the following general formula (a2) can be cited.

[Chemistry 7]

In equation (a2) above, R is defined in the same way as in equation (a) above, where ^R6 is an hydrocarbon with 1 to 10 carbon atoms or the structure described in equation (a3) below. When ^R6 is an hydrocarbon, it can be a ring structure bonded to R, or it can be a form where N bonded to ^R6 is directly bonded to R. In equation (a2), n is an integer greater than or equal to 1, and m is an integer greater than or equal to 0.

[Chemistry 8]

As a nitrogen-containing modifier, the epoxide compound is preferably a compound having one or more diglycidylamino groups and one or more glycidyloxy groups in its molecule.

Examples of epoxide compounds used as nitrogen-containing modifiers include: N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxy-cyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, and 4-(4-glycidoxyphenoxy)-phenylene. 4-(4-diglyceryloxybenzyl)-(N,N-diglyceryl)aniline, 4-(N,N'-diglyceryl-2-piperyl)-diglyceryloxybenzene, 1,3-bis(N,N-diglycerylaminomethyl)cyclohexane, N,N,N',N'-tetraglyceryl-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-glycidylpiperazolyl)-(N,N-diglycidyl)aniline Examples of such formulations include 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N,N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N,N-diglycidylaniline, N,N-diglycidyl-o-toluidine, and N,N-diglycidylaminomethylcyclohexane, but these are not limited to the above. Among these, N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane are particularly preferred.

From the viewpoint of effectively and reliably exerting the effect of modifying conjugated diene polymers 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-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperidyl)propyltriethoxysilane, 1-[3-(triethoxysilyl)-propyl]-3-methylhexanepyrimidine, 3-(4-trimethylsilyl-1-piperidyl)propyltriethoxysilane. 3-(3-Triethylsilyl-1-imidazolidine)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahedrinidyl)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-silanecyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silanecyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silanecyclohexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl) Examples of such examples include 2,2-dimethoxy-1-phenyl-1-aziro-2-siliconcyclopentane, 2,2-diethoxy-1-butyl-1-aziro-2-siliconcyclopentane, 2,2-dimethoxy-1-methyl-1-aziro-2-siliconcyclopentane, 2,2-dimethoxy-8-(4-methylpiperyl)methyl-1,6-dioxo-2-siliconcyclooctane, and 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxo-2-siliconcyclooctane, but not limited to the above.

<As a modifier of alkoxysilane compounds having nitrogen atoms> The modified conjugated diene polymer of this embodiment is preferably modified using alkoxysilane compounds having nitrogen atoms. That is, it is preferably modified with modifier residues derived from alkoxysilane compounds having nitrogen atoms.

As alkoxysilane compounds containing nitrogen atoms, the following are particularly desirable examples. 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-silazanecyclopentane)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-silazane-2-azacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3 -(1-methoxy-2-methyl-1-silicon-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silicon-2-cyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silicon-2-azacyclopentane)propyl]-1, 3-Propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silanecyclopentane)propyl]-1,3-diaminomethylcyclohexane, tetra(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, penta(3 -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-azino-2-siliconcyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, [3-(2,2-dimethoxy-1-azino-2-siliconcyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azinocyclopentane)propyl]silane, 3-Tris[2-(2,2-dimethoxy-1-azino-2-siliconcyclopentane)ethoxy]silyl-1-trimethoxysilylpropane, 1-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azinocyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)cyclohexane, 1-[3-(2,2-dimethoxy-1-azino-2-siliconcyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)cyclohexane, [3-(2,2-dimethoxy-1-azino-2-siliconcyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane, 3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexyl-[3-(2,2-dimethoxy-1-azino-2-siliconcyclopentane)propyl] ether, (3-trimethoxysilylpropyl) phosphate.

Examples include: bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl] phosphate, bis[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-trimethoxysilylpropyl) phosphate, tris[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl] phosphate, N-(1,3-dimethylbutylene)-3-(triethoxysilyl)-1-propylamine, 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-silazinocyclopentane, and 2-methoxy-2-methyl-1-(4-methoxybenzylaminoethyl)-1-aza-2-silazinocyclopentane.

Furthermore, examples include: 1-methyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-methyl-4-[3-(triethoxysilyl)propyl]piperidine, 1-methyl-4-[3-(methyldimethoxysilyl)propyl]piperidine, 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).

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-tetramethoxydisiloxane-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-Tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethane-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-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.

Among modifiers containing nitrogen atoms, protected amine compounds formed by replacing active hydrogen with a protecting group include 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)aminopropylmethyldiethoxysilane. 3-(4-trimethylsilyl-1-piperazolidinyl)propyltriethoxysilane, 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-piperazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-piperazolidinyl)propyltrieth ... -hexamethylenepyrimidinyl)propyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silanecyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silanecyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silanecyclohexane, 2,2-Dimethoxy-1-(3-Dimethoxymethylsilylpropyl)-1-aza-2-silazinocyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silazinocyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silazinocyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silazinocyclopentane, but not limited to the above.

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-benzylene-3-methyl(dimethoxysilyl)-1-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-silazinocyclopentane, and 2-methoxy-2-methyl-1-(methylisobutylaminoethyl)-1-aza-2-silazinocyclopentane, 1-trimethylsilyl-4-[3-(trimethoxysilyl)propyl]piperidine, 1-trimethylsilyl-4-[3-(triethoxysilyl)propyl]piperidine.

In the manufacturing process of the modified conjugated diene polymer of this embodiment, when performing the coupling step, it is particularly preferred to use a nitrogen-containing modifier represented by any 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.

[Chemistry 9]

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

[Chemistry 10]

In formula (B) above, A represents an alkyl group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and not having active hydrogen. ^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 represents an integer from 1 to 3, c 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.

[Chemistry 11]

In formula (C), ^R24 , ^R25 , ^R26 , ^R27 , ^R28 , and ^R29 each independently represent an alkyl group having 1 to 20 carbon atoms, or an aryl group having 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 an integer from 1 to 3, and the sum of s, t, and u is an integer of 4 or more.

[Chemistry 12]

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

Specifically, in formula (D) above, ^B1 and ^B2 each independently represent 1 to 10 alkyl groups, ^R33 to ^R36 each independently represent alkyl groups with 1 to 10 carbon atoms, ^L1 to ^L4 each independently represent tetravalent alkyl 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.

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

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

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 (A), but it is preferred to react at a temperature above 0°C and below 120°C, and preferably for a reaction time of more than 30 seconds.

The amount of modifier added as 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 that constitutes the 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 to a better 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.

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 relative to the mole number of the polymerization initiator.

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

[Chemistry 13] (Chemical I)

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

[Chemistry 14] (Chemical II)

In formula (Chemical II), ^D2 represents a single bond or a divalent hydrocarbon having 1 to 20 carbon atoms. ^D3 represents an alkyl group having 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.

[Chemistry 15] (Chemical III)

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

[Chemistry 16] (Chemical IV)

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

In formula (B) above, the modifier used when A is represented by formula (I) can be exemplified by, for example: tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]amine, bis[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]- (3-Trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-siliconcyclopentane)propyl]amine, tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-siliconcyclopentane)propyl]amine, bis[3-(2,2-diethoxy-1-aza-2-siliconcyclopentane)propyl]amine [-2-siliconoxycyclopentane)propyl]-(3-triethoxysilylpropyl)amine, tris[3-(2,2-diethoxy-1-aza-2-siliconoxycyclopentane)propyl]amine, tetra(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-siliconoxycyclopentane)propyl]amine, tetra(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-siliconoxycyclopentane)propyl] [3-(2,2-dimethoxy-1-aza-2-siliconcyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-siliconcyclopentane)propyl]-(3-trimethoxysiliconcyclopropyl)-1,3-propanediamine, but not limited to the above.

For example, tetra[3-(2,2-dimethoxy-1-aza-2-silanecyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silane-2-aza-cyclopentane)propyl]-1,3-propanediamine, bis( 3-Trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-azino-2-silicon-cyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azino-cyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-azino-2-silicon-cyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-azino-2-silicon-cyclopentane)propyl]-1,3-propanediamine [3-(1-methoxy-2-trimethylsilyl-1-siloxane-2-aziroxane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aziroxane-2-siloxane)propyl]-[3-(1-methoxy-2-dimethylsilyl-1-siloxane-2-aziroxane)propyl]-[3-(1-methoxy-2-dimethylsilyl-1-aziroxane-2-aziroxane)propyl]-[3-(1-methoxy-2-dimethylsilyl-1-aziroxane-2-aziroxane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aziroxane-2-sil ...1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aziroxane-2-siloxane)propyl]-[3-(1-methoxy-2-dimethylsilyl-1-aziroxane-2-aziroxane-2-propanediamine]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aziroxane-2-propanediamine)propyl]-[3-(1-methoxy-2-dimethylsilyl-1-aziroxane-2-propanediamine]-1,3-propanediamine]-1,3-propanedi [-trimethylsilyl-1-silazane-2-azirmonocyclopentane)propyl]-1,3-propanediamine, tetra(3-triethoxysilylpropyl)-1,3-propanediamine, tri(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-azirmono-2-silazane)propyl]-1,3-propanediamine.

Furthermore, examples include: bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetra[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetra[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, and tetra[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine. 2-Diethoxy-1-aza-2-silazane-(cyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-silazane-2-aza-cyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza- 2-Silylcyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silyl-2-azirylcyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aziryl-2-silylcyclopentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-silyl-2-propane ... [-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silazane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-silazane-2-azacyclopentane)propyl]-1,3-propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane.

Furthermore, examples include: tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-1,3- Diaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2-siliconcyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, tetra[3-(2,2-dimethoxy-1-aza-2-siliconcyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl) )-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azirmonocyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-azirmono-2-silicon-2-cyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-cyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-cyclopentane)propyl] [3-(2,2-dimethoxy-1-azino-2-silicon-cyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azino-cyclopentane)propyl]-1,3-diaminomethylcyclohexane.

Furthermore, examples include: tris[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silazane-2-aza-cyclopentane)propyl]-1,3-diaminomethylcyclohexane, tetra(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silazanecyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis(3- Triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-siliconcyclopentane)propyl]-1,3-diaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-siliconcyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetra[3-(2,2-diethoxy-1-aza-2-siliconcyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethyl] [3-(2,2-diethoxy-1-azino-2-azino-cyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-azino-2-azino-cyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-azino-2-azino-cyclopentane)propyl]-1,3-diaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-azino-2-azino-cyclopentane)propyl]-(3-triethoxysilylpropyl)-[3 -(1-ethoxy-2-trimethylsilyl-1-silazane-2-azacyclopentane)propyl]-1,3-diaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-azaazane-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.

In formula (B) above, the modifier used when A is represented by formula (Chemical II) can be exemplified by, for example: tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propyl]-(3-trimethoxysilane) 2-Triethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silanecyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silanecyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N ¹ , ^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.

In formula (B) above, the modifier used when A is represented by formula (Chemical III) can be exemplified by, for example: 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-silazane-2-azirmonocyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-azirmono-2-silazane)propyl]silane, (3-trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-silazane-2-azirmonocyclopentane)-bis[3-(2,2-dimethoxy-1-azirmono-2-silazane)propyl]silane, bis [3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azinon-cyclopentane)-bis[3-(2,2-dimethoxy-1-azinon-2-silicon-cyclopentane)propyl]silane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-azinon-2-silicon-cyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silicon-2-azinon-cyclopentane)propyl]silane [3-(2,2-dimethoxy-1-aziro-2-azirocyclopentane)propyl]silane, bis[3-(1-methoxy-2-trimethylsilyl-1-aziro-2-azirocyclopentane)propyl]-bis(3-trimethoxysilylpropyl)silane, and bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-aziro-2-azirocyclopentane)propyl]silane, but not limited to the above.

In formula (B) above, the modifier used when A is represented by formula (Chemical IV) can be exemplified by, for example, 3-tris[2-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)propane and 3-tris[2-(2,2-dimethoxy-1-aza-2-silazanecyclopentane)ethoxy]silyl-1-trimethoxysilylpropane, but is not limited to the above.

The amount of modifier added as expressed in 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 expressed in formula (B). In this way, the reaction between the conjugated diene polymer and the modifier can be adjusted in the manner required by stoichiometric ratio.

More specifically, the amount of polymerization initiator and coupling modifier represented by formula (B) added can be adjusted such that the mole 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 mole number of the polymerization initiator. In this case, the functional base of the modifier in formula (B) above (for example, 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.

Examples of the 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.

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

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

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 that constitute the 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.

Examples of modifiers represented by formula (D) above include: 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropane-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethyl ... Methoxydisiloxane-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.

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.

Regarding the amount of modifier added as represented by formula (D) above, the total mole number 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.

[Method for Manufacturing Conjugated Diene Polymers] The method for manufacturing modified conjugated diene polymers according to 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 continuous reactor has a monomer addition section, which adds at least one conjugated diene compound and an aromatic vinyl compound during the polymerization step. The manufacturing method also includes a coupling step: reacting the conjugated diene polymer obtained by the polymerization step with a modifier having nitrogen atoms.

(Polymerization Initiator) As a polymerization initiator, at least an organic monolithic lithium compound can be used. Examples of organic monolithic lithium compounds include, but are not limited to, low-molecular-weight compounds and soluble oligomers. Furthermore, regarding the bonding form between the organic group and the lithium, examples of organic monolithic lithium compounds include compounds with carbon-lithium bonds, compounds with nitrogen-lithium bonds, and compounds with tin-lithium bonds. The amount of organic monolithic lithium compound used as a polymerization initiator is preferably determined based on the molecular weight of the target conjugated diene polymer or 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, there is a tendency 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.

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 the conjugated diene polymer, the organolithium compound is preferably an alkyl lithium compound having a substituted amino group, or a dialkylamino lithium. In this case, a conjugated diene polymer having a nitrogen atom containing an amino group at the polymerization initiation end can be obtained. The substituted amino group is an amino group that does not have active hydrogen or has a structure that protects active hydrogen. Examples of alkyl lithium compounds having an amino group that does not have active hydrogen include, but are not limited to, 3-dimethylaminopropyl lithium, 3-diethylaminopropyl lithium, 4-(methylpropylamino)butyl lithium, and 4-hexamethyleneiminobutyl lithium. Alkyl lithium compounds having an amino group that protects active hydrogen include, for example, 3-bis(trimethylsilylaminopropyl) lithium and 4-trimethylsilylmethylaminobutyl lithium, but are not limited to these. Dialkylamino lithium compounds include, for example, dimethylamino lithium, diethylamino lithium, dipropylamino lithium, dibutylamino lithium, di-n-hexylamino lithium, diheptylamino lithium, diisopropylamino lithium, dioctylamino lithium, di-2-ethylhexylamino lithium, didecylamino lithium, ethylpropylamino lithium, ethylbutylamino lithium, and ethylbenzylamino lithium. Lithium oxymethylamine, lithium methylphenethyl oxymethylamine, lithium hexamethylene oxyimide, lithium pyrrolidine, lithium piperidinium, lithium heptamethylene oxyimide, lithium α-linolenic acid, 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 having substituted amino 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.

Furthermore, the polymerization initiator can be generated by reacting an aromatic vinyl compound having substituted amino groups 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 the polymer chain. From the viewpoint of industrial availability and ease of controlling the polymerization reaction, alkyl lithium compounds are preferred as the aforementioned organolithium compounds. In this case, a conjugated diene polymer 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, dibutyllithium, tributyllithium, n-hexyllithium, benzyllithium, phenyllithium, and styrene. From the perspective of industrial availability and ease of controlling the polymerization reaction, n-butyllithium and dibutyllithium are preferred as alkyllithium compounds. These monolithic organolithium compounds can be used alone or in combination of two or more. They can also be used in combination with other organometallic compounds. Examples of such other organometallic compounds include, for example, alkaline earth metal compounds, other alkaline metal compounds, and other organometallic compounds. Examples of alkaline earth metal compounds include, for example, organomagnesium compounds, organocalcanthite compounds, and organostrontium compounds, but are not limited to these. Examples also include, for example, alkaline earth metal alkoxides, sulfonates, carbonates, and amide compounds. Examples of organomagnesia compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

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 and aromatic vinyl compounds. 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 and aromatic vinyl compounds used is set at 100 kg, the amount of polymerization initiator used is preferably 0.15 mol or more and 1.5 mol or less.

(Polar substances) In the method for manufacturing modified conjugated diene polymers according to this embodiment, polar substances may be added together with the polymerization initiator. Polar substances can randomly copolymerize aromatic vinyl compounds with conjugated diene compounds, and 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.

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; alkaline metal alkoxide compounds such as potassium tertiary valerate, potassium tertiary butyrate, sodium tertiary butyrate, and sodium valerate; phosphine compounds such as triphenylphosphine, etc., but not limited to the above. One of these polar substances may be used alone, or two or more may be used in combination.

There is no particular limitation on the amount of polar substances used, and the choice can be made according to the purpose, but it is preferable to use more than 0.005 mol and less than 100 mol relative to 1 mol of polymerization initiator.

This polar substance can be used as a regulator of the microstructure of the conyodene moiety in the modified conyodene polymer of this embodiment, and is used in appropriate amounts according to the required amount of vinyl bonds. Most polar substances also exhibit effective randomization effects in the copolymerization of conyodene compounds and aromatic vinyl compounds, and have the tendency to adjust the randomness of aromatic vinyl monomers and conyodene monomers in each polymer segment.

(Polymerization 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 section. The above polymerization steps (P1) and (P2) can each be carried out using one or more reactors connected together. The shape of the reactor can be a trough type, a tubular type, etc., equipped with a stirrer. The polymerization steps (P1) and (P2) do not need to be assigned to individual reactors. For example, it can be set to start the polymerization step (P2) 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 of the polymerization steps (P1) and (P2). Each reactor can have its own temperature control function.

(Solids content) 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 solids content. Furthermore, the solids content in this specification refers to the mass of modified conjugated diene polymer recovered per unit time at the measurement point. The mass of the modified conjugated diene polymer only includes the polymerized product formed by reaction with the polymerization initiator; unreacted conjugated diene compounds, aromatic vinyl compounds, solvents, etc., are not included in the mass.

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 and the aromatic vinyl compound added at the time of measurement, which is the mass of the polymer that has been formed after the reaction is completed at the time of measurement. That is, it is calculated using the above-mentioned solids amount and the following formula (2).

[Number 5]

Furthermore, the amount of bonded conjugated diene monomers and the amount of bonded aromatic vinyl monomers of the solid components obtained by the above solid content measurement are used respectively, and the conversion rate of each conjugated diene compound and aromatic vinyl compound is calculated using the following formulas (3) and (4).

[Number 6]

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.

In the polymerization step (P1) described above, the conversion rate of the aromatic vinyl compound in the polymerization intermediate 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 compound is not within the above range, the aromatic vinyl monomer units tend to be distributed more heavily in the second polymer chain segment, and the tanδ peak height tends to decrease. On the other hand, if the conversion rate of the aromatic vinyl compound is within the above range, the distribution of the aromatic vinyl monomer units tends to become more uniform, and the tanδ peak height tends to increase. Especially when the amount of polar substance added is small and the amount of aromatic vinyl compound added is large, the conversion rate of the aromatic vinyl compound tends to deviate from the above range.

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

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

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 preferably 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 has a discharge section that continuously discharges polymer solution from the end opposite to the raw material supply section.

The amount of the bonded 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).

The amount of vinyl bonds _Y1 in the bonded conjugated diene of the first polymer segment can be controlled by adjusting the amount of polar material added in the polymerization step (P1) and the polymerization temperature.

The conjugated diene polymer solution following polymerization step (P1) is continuously extracted from the reactor and transported to the next step. Preferably, the liquid is transported to, for example, the polymerization step (P2) of the second polymer chain segment described below. Furthermore, the starting point of polymerization step (P2) is defined as the aforementioned monomer addition section.

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 second polymer segment is introduced into the end of the first polymer segment by having a monomer addition part of a newly added raw material compound after the polymerization step (P1), 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).

The configuration of the connection between polymerization steps (P1) and (P2) where the aforementioned monomer addition section is located is not particularly limited. However, 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 aforementioned continuous reactor. Furthermore, the added raw material compound is preferably a conubenzene compound, an aromatic vinyl compound, or a polar substance. From the viewpoint of improving the fuel-saving performance of the modified conubenzene polymer sulfide of this embodiment, it is more preferably a conubenzene compound, an aromatic vinyl compound, a polar substance, or the following branching agent. An inert solvent may be added to the aforementioned monomer addition section.

The lower limit of the total mass of conodelid compounds and aromatic vinyl compounds added in the monomer addition section relative to the total mass of conodelid compounds and aromatic vinyl compounds added throughout 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 conodelid compounds and aromatic vinyl compounds added in the monomer addition section relative to the total mass of conodelid compounds and aromatic vinyl compounds added throughout the entire polymerization step is preferably 90% or less, more preferably 80% or less, and even more preferably 50% or less. Within the above range, there is a tendency to more significantly improve the opposing properties of wet grip and abrasion resistance.

The amount of the bonded 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 above polymerization step (P2).

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.

The conjugated diene polymer solution after the polymerization step (P2) is continuously extracted from the reactor and transported to the next step. As an example, the liquid transport destination may be the following coupling step.

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, simply increase the ratio of monomer added in polymerization step (P1) and increase the polymerization conversion rate in polymerization step (P1).

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

In the method for manufacturing modified conjugated diene polymers according to this embodiment, the polymerization temperature in the polymerization step is preferably the temperature for conducting living anionic polymerization. From a production perspective, it is more preferably above 0°C and below 120°C, and even more preferably above 50°C and below 100°C. Within this range, the tendency of the modifier to react with the active terminals after polymerization can be sufficiently ensured. More preferably, it is above 70°C and below 95°C.

In the method for manufacturing modified conjugated diene polymers according to this embodiment, to obtain a higher molecular weight distribution, it is only necessary to reduce the height (L)/diameter (D) of the tank 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 will vary depending on the type of coupling agent used.

(Coupling Step) A coupling step is performed in the method for manufacturing the modified conjugated diene polymer of this embodiment. This coupling step involves modifying the active ends of the conjugated diene polymer obtained through the polymerization step of polymer chain segments using a nitrogen-containing modifier (preferably an alkoxysilane modifier with nitrogen atoms). In the coupling step, one end of the active end of the conjugated diene polymer is modified using a nitrogen-containing modifier to obtain the modified conjugated diene polymer.

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

In the method for manufacturing modified conjugated diene polymers according to 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, but are not limited to, aqueous solutions of carboxylic acids, inorganic acids, such as stearic acid, oleic acid, and poly(decacarbonyl) (a mixture of carboxylic acids with 9 to 11 carbon atoms, with 10 carbon atoms as the main component), and carbon dioxide.

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. The rubber stabilizer is not limited to the following substances; known stabilizers can be used, such as preferably 2,6-di-tertiary butyl-4-hydroxytoluene (BHT), octadecyl 3-(4'-hydroxy-3',5'-di-tertiary butylphenol)propionate, 2-methyl-4,6-bis[(octylthio)methyl]phenol, and other antioxidants.

(Step of obtaining polymer from polymer solution) The method for producing modified conjugated diene polymers according to this embodiment may include a step of obtaining the obtained modified conjugated diene polymer from a polymer solution. As such a method, known methods may be used, for example, the method described below. Examples of methods include: separating the solvent by steam stripping, filtering the modified ethylene-based polymer, and then dehydrating and drying it to obtain the modified ethylene-based polymer; concentrating it in a flash tank and then volatilizing it using an exhaust extruder to obtain the modified ethylene-based polymer; and directly volatilizing it using a rotary dryer to obtain the modified ethylene-based polymer.

(Steps for obtaining 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 oils, liquid rubbers, and resins can be added to the manufactured modified conjugated diene polymers to produce oil-extended modified conjugated diene polymers. Furthermore, the oil-extended modified conjugated diene polymers include not only oil-containing oil-extended modified conjugated diene polymers, but also those containing liquid polybutadiene or various resins other than oil. This further improves the processability of the modified conjugated diene polymers.

A preferred method for adding filler oil to modified conjugated diene polymers is as follows: adding the filler oil to a modified conjugated diene polymer solution and mixing to form an oil-extended polymer solution, followed by solvent removal from the oil-extended polymer solution; however, this 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 flaxseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, castor oil, tung oil, pine oil, sunflower seed oil, palm oil, olive oil, coconut oil, peanut oil, and grapeseed oil. Among these, from the perspectives of environmental safety, preventing oil seepage, and wet grip properties, it is preferable to use aromatic oil substitutes with a polycyclic aromatic hydrocarbon (PCA) content of 3% by mass or less based on the IP346 standard. As aromatic oil substitutes, 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.

Examples of liquid rubbers include, but are not limited to, liquid polybutadiene and liquid styrene-butadiene rubber. Examples of resins include, for example, aromatic petroleum resins, benzofuran-indene resins, terpene resins, rosin derivatives (including tung oil resin), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, and phenolic resins. Emulsions, including but not limited to tert-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, oligomers of monoenes, oligomers of dienes, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of monofunctional or polyfunctional alcohols. One or more of these resins may be used alone. During hydrogenation, all unsaturated groups may be hydrogenated, or some may remain. The amount of any one of the following selected materials—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.

[Rubber Composition] The modified conjugated diene polymer of this embodiment can be supplemented with fillers to form 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, which includes the modified conjugated diene polymer of this embodiment described above; and a filler, which is 5.0 parts by weight or more and 150 parts by weight or less relative to 100 parts by weight of the rubber component, and preferably the rubber component comprises 10 parts by weight or more of the modified conjugated diene polymer of this embodiment relative to 100 parts by weight of the total amount of the rubber component. By dispersing the filler in a rubber component comprising the modified conjugated diene polymer of this embodiment, a rubber composition with superior processability during vulcanization, and with better low hysteresis loss, destructive properties, and abrasion resistance of its vulcanizates, can be obtained. Furthermore, by including the modified conjugated diene polymer of this embodiment in the rubber component at a specified ratio, there is a tendency for further improvements in processability and abrasion resistance.

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 automotive parts such as tires and vibration-damping rubber, and in vulcanized rubber applications such as shoes. Such fillers can be used alone or in combination with two or more.

There are no particular limitations on the silica-based inorganic filler, and known fillers can be used. However, it is preferred to use solid particles containing _SiO2 or _Si3Al as structural units, and even more preferably solid particles containing _SiO2 or _Si3Al as the main structural unit. Here, the main component refers to the component contained in the silica-based inorganic filler at more than 50% by mass, preferably more than 70% by mass, and even more preferably more than 80% by mass.

Examples of silica-based inorganic fillers include, but are not limited to, silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fibers. Silica-based inorganic fillers with hydrophobic surfaces, as well as mixtures of silica-based inorganic fillers and inorganic fillers other than silica-based fillers, can also be used. Among these, silica or glass fibers are preferred, and silica is more preferred, from the viewpoint of further improving the strength and wear resistance of the rubber composition of this embodiment. There is no particular limitation on the type of silica used; examples include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred from the viewpoint of further improving the breaking strength of rubber compounds.

From the perspective of more reliably obtaining rubber compositions with practically good wear 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 areas (e.g., 200 ^m² /g or more), the rubber composition of this embodiment further improves the dispersibility of silica. As a result, there is a tendency to obtain rubber compositions with superior abrasion resistance, breaking strength, and low hysteresis loss.

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.

As a metal oxide, there are no particular limitations as long as it is a solid particle with the chemical formula M _x O _y (M represents a metal atom, and x and y 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.

There are no particular limitations on what constitutes a metallic hydroxide; examples include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

Relative to 100 parts by weight of rubber component, the filler content in the rubber composition of the modified conjugated diene polymer using 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 filler, the rubber composition tends to have better processability during vulcanization, and its vulcanizates tend to have better low hysteresis loss, destructive properties, and abrasion resistance.

From the viewpoint of effectively imparting the performance required for applications such as tires with good dry grip and electrical conductivity, the rubber composition of the modified conjugated diene polymer of this embodiment preferably contains 0.5 parts by weight and less than 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 less than 100 parts by weight of carbon black, and more preferably 5.0 parts by weight and less than 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.

Rubber compositions of modified conjugated diene polymers using this embodiment may further include a silane coupling agent. By including a silane coupling agent in the rubber composition, the interaction between the rubber component and the filler can be further improved. As a silane coupling agent, it is preferably a compound having a sulfur bond moiety and an alkoxysilyl or silanol moiety in one molecule, but is not limited to the above. Examples of such compounds include, for example: bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide, but are not limited to the above.

In the rubber composition of the modified conjugated diene polymer using this embodiment, the content of silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of filler. 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.

Rubber compositions using the modified conjugated diene polymers of this embodiment may include rubber-like polymers (hereinafter referred to as "rubber-like polymers") other than the modified conjugated diene polymers of this embodiment as rubber components. Examples of rubber-like polymers include, but are not limited to, conjugated diene polymers and their hydrogenates, random copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenates, block copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenates, non-diene polymers, and natural rubber. Examples of rubber-like polymers include, but not limited to, styrene-based elastomers such as butadiene rubber and its hydrogenates, isoprene rubber and its hydrogenates, styrene-butadiene rubber and its hydrogenates, styrene-butadiene block copolymers and their hydrogenates, and styrene-isoprene block copolymers and their hydrogenates, as well as acrylonitrile-butadiene rubber and its hydrogenates. Examples of non-diene polymers include, but are not limited to, olefinic 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 rubbers include, for example, RSS3-5, SMR, and epoxidized natural rubber used in smoked sheets.

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

From the perspective of balancing the abrasion resistance, breaking strength, low hysteresis loss, and processability of rubber compositions, the mass-average molecular weight of the rubber 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 polymers, i.e., so-called liquid rubber, can also be used as rubber polymers. One type of such rubber polymer can be used alone, or two or more can be used in combination.

When the rubber composition of the modified conjugated diene polymer using this embodiment includes the modified conjugated diene polymer of this embodiment, and further includes the aforementioned rubber polymer, the content ratio (mass ratio) of the modified conjugated diene polymer relative to the rubber polymer (modified conjugated diene polymer/rubber 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.

From the viewpoint of further improving the processability of the rubber composition of this embodiment, in addition to the rubber component, a rubber softener may also be added. As a rubber softener, the same type exemplified as those included in the aforementioned modified conjugated diene polymers can be used, but mineral oils, 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 the rubber component, and referred to as processing oils or filler oils, are mixtures of aromatic rings, cycloalkane rings, and paraffin chains. Among them, those belonging to the paraffin chain and having more than 50% carbon in the total carbon number are called paraffinic polymers; those belonging to the cycloalkane ring and having more than 30% but less than 45% carbon in the total carbon number are called cycloalkane polymers; and those belonging to the aromatic carbon group and having more than 30% carbon in the total carbon number are called aromatic polymers. Rubber compositions using the modified conjugated diene polymers of this embodiment preferably include a rubber softener with an appropriate 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 during the preparation of the rubber composition. In the rubber composition of the modified conjugated diene polymer using this embodiment, the content of rubber softener relative to 100 parts by weight of 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 using a rubber softener with a content of less than 100 parts by weight relative to the rubber component, exudation can be suppressed, and the stickiness of the rubber compound surface can be further suppressed.

Rubber compositions can be manufactured by mixing modified conjugated diene polymers, rubber-like 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 drums, Bamboo mixers, kneaders, single-screw extruders, twin-screw extruders, or multi-screw extruders; and methods involving dissolving and mixing the components, followed by heating to remove the solvent. Of these, melt mixing using rollers, Bamboo mixers, kneaders, or extruders is preferred from the viewpoints of productivity and good mixing properties. Furthermore, the rubber components can be mixed with fillers, silane coupling agents, and additives in one go, or they can be mixed in multiple stages.

Rubber compositions of modified conjugated diene polymers using this embodiment can be vulcanized using a vulcanizing agent to produce sulfides. The vulcanizing agent is not particularly limited, and 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.

In the rubber composition of the modified conjugated diene polymer using 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 rubber component. The vulcanization method can be any previously known method. Furthermore, the vulcanization temperature is preferably 120°C or more and 200°C or less, more preferably 140°C or more and 180°C or less.

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. As vulcanization aids, such as zinc oxide and stearic acid, but not limited to the above. The content of the vulcanization accelerator and the vulcanization aid, relative to 100 parts by weight of the rubber component, is preferably 0.01 parts by weight or more and 20 parts by weight or less, more preferably 0.1 parts by weight or more and 15 parts by weight or less, respectively.

In rubber compositions of modified conjugated diene polymers using this embodiment, various additives other than those mentioned above, such as softeners and other fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, may be used to the extent that they do not impede the effectiveness of this embodiment. As softeners, known softeners can be used. Other fillers include, for example, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate, but are not limited to these. As a heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant, it can be made from known materials.

Rubber compositions of modified conjugated diene polymers using the present invention can be suitably used as rubber compositions for tires. The rubber compositions of the present invention are not particularly limited, and can be suitably used for various types of tires, such as fuel-efficient tires, all-season tires, high-performance tires, and nail-free tires; and for various parts of the tire, including the tread, carcass, sidewall, and bead.

Furthermore, unless otherwise specified, the numerical ranges described above as preferred ranges can be replaced with numerical ranges formed by arbitrarily combining the values described as upper limits and the values described as lower limits. [Example]

The following specific embodiments and comparative examples illustrate the present invention in more detail, but the present invention is not limited by the following embodiments and comparative examples.

The various physical properties in the embodiments and comparative examples were determined by the methods shown below.

((Physical Property 1) Conversion Rate) (Solids Content) The solids content in the modified ethylene 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 volume of the modified ethylene diene polymer solution flowing through the measuring point is collected for 3 minutes, and a polymerization terminator is added immediately. Subsequently, it is transferred to a heat-resistant dish and dried in an oven at 140°C for at least 30 minutes, and the mass (M) of the remaining solids is measured. Here, the solids content (m) is calculated using the following formula (I).

[Number 7]

Furthermore, the measuring points are set as the discharge section of the polymerization step (P1) for synthesizing the first polymer segment and the discharge section of the polymerization step (P2) for forming the second polymer segment, and the solid content in these steps is set as _m1 and _m2 , respectively. The conversion rate _cbd of the conjugated diene compound and the conversion rate cst of the aromatic vinyl compound in the polymerization step (P1) for synthesizing the first polymer segment are calculated using the following formulas (II) and ( _III) , respectively. In this embodiment, _U1 is the mass of 1,3-butadiene added per unit time in the first unit, and _V1 is the mass of styrene added per unit time in the first unit. In the following formulas, _X1 represents the amount of bonded styrene in the first polymer segment. Furthermore, _X2 represents the amount of bonded styrene in the second polymer segment.

[Number 8]

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 per unit time in the first unit, and _V1 is the mass of styrene added per unit time in the first unit.

[Number 9]

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

(Mass ratios _r1 and _r2 of the first polymer chain segment and the second polymer chain segment) The mass ratios r of the first polymer chain segment and the second polymer chain segment are respectively shown in the following formulas (V) and (VI), and are obtained by summing the solids _m1 and _m2 of each discharge portion of the polymerization step (P1) for synthesizing the first polymer chain segment and the polymerization step (P2) for forming the second polymer chain 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.

[Number 10]

(Ratio of the mass ratio of polymer chain segments R) The ratio of the mass ratio of polymer chain segments R (＝r ₁ /r ₂ ) is obtained using the following formula (VII).

[Number 11]

((Physical Property 3) Amount of Bonded Aromatic Vinyl Monomer Units (Amount of Bonded Styrene))(Amount of Bonded Styrene in Conjugated Diene Polymers X _all ) A conjugated diene polymer collected from the discharge section of the polymerization step (P2) that forms the second polymer chain segment, without rubber softener, was used as a sample. 100 mg of the above sample was diluted to 100 mL with chloroform to obtain the test sample. The amount of bonded styrene (mass %) relative to 100% by 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).

(Amount of bonded styrene in the first polymer segment X ₁ ) The solids composition of the polymer solution in the discharge section of the polymerization step (P1) that transforms the sample from a conjugated diene polymer to synthesize the first polymer segment. For 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.

(Amount of bonded styrene in the second polymer segment _X2 ) 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, the amount of bonded styrene ( _X2 ) in the second polymer segment is calculated using the following formula (VIII).

[Number 12] Numerical Expressions (VIII)

(Difference in the amount of bonded styrene between the first polymer segment and the second polymer segment | _X2 - _X1 |) In order to evaluate the randomness of styrene, the difference in the amount of bonded styrene between the first polymer segment and the second polymer segment is calculated using | _X2 - _X1 |.

((Property 4) Vinyl bond content in bonded conjugated dienes (1,2-vinyl bond content in bonded butadiene) (Vinyl bond content Y _all of conjugated diene polymers) Conjugated diene polymers without rubber softeners, collected from the discharge section of the polymerization step (P2) that forms the second polymer chain segment, were used as samples. 50 mg of the above sample was dissolved in 10 mL of carbon disulfide and set 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 (mol%) was determined from the absorbance at a specified wavenumber according to Hampton’s method (RR Hampton, Analytical Chemistry 21, 923 (1949)).

(Vinyl bond content _Y1 in the first polymer segment) is the solid composition of the polymer solution in the discharge section of the polymerization step (P1) that transforms the sample from a conjugated diene polymer to synthesize the first polymer segment. For other conditions, the vinyl bond content is calculated using the same method as for the vinyl bond content of the conjugated diene polymer.

(Vinyl bond amount _Y2 in the second polymer segment) The vinyl bond amount in the second polymer segment is calculated by the following formula (IX) based on the solid content _m1 , _m2 in the polymerization step (P1) for synthesizing the first polymer segment and the polymerization step (P2) for forming the second polymer segment, and the vinyl bond amount _Y1 , _Yaall in the bonded conjugated diene.

[Number 13] Numerical expression (IX)

[Number 14] Numerical expression (X)

((Property 5) Estimated glass transition temperature, estimated glass transition temperature difference) Use formula (iii) to calculate the estimated glass transition temperatures (estimated Tg ₁ , estimated Tg ₂ , estimated Tg) of the first polymer segment, the second polymer segment, and the modified conjugated diene polymer. When calculating estimated Tg ₁ and estimated Tg ₂ , simply replace X _all and Y _all of the microstructure with X ₁ , Y ₁ and X ₂ , Y _2, respectively.

[Number 15]

Furthermore, the difference in estimated glass transition temperature is obtained using the following formula (XI).

[Number 16]

(Physical Property 6) Molecular Weight: Using the modified conjugated diene polymers of the embodiments and comparative examples as samples, a GPC analyzer (manufactured by Tosoh Corporation, trade name "HLC-8320GPC") with three columns filled with polystyrene gel as the packing material was used. An RI detector (manufactured by Tosoh Corporation, trade name "HLC8020") was used to measure the chromatograms. 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. 10 mg of 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 assay apparatus, and the assay was performed at an oven temperature of 40°C and a THF flow rate of 0.35 mL/min.

(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 characteristic of the modified alkaline polymer component adsorbed onto a GPC column with silica gel as the filler was applied for determination. For a sample solution containing the sample and low molecular weight internal standard polystyrene, the adsorption amount on the silica-based column was determined based on the difference between the chromatogram measured by the polystyrene-based column and the chromatogram measured by the silica-based column, and the modification rate was calculated. <Preparation of Sample Solution>: 10 mg of sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to prepare the sample solution. <GPC Determination Conditions Using Polystyrene-Based Columns>: A Tosoh HLC-8320GPC was used. THF containing 5 mmol/L triethylamine was used as the dissolution solution. 10 μL of the sample solution was injected into the apparatus. The chromatography was performed using an RI detector at a column oven temperature of 40°C and a THF flow rate of 0.35 mL/min. The column consisted of three Tosoh TSKgel SuperMultipore HZ-H tubes, with a Tosoh TSKguardcolumn SuperMP(HZ)-H tube connected to the front end as a guard column. <GPC Measurement Conditions Using Silicon Dioxide-Based Columns> GPC measurements were performed using a Tosoh HLC-8320GPC and an RI detector (Tosoh HLC8020). THF was used as the dissolution solution; 50 μL of the sample solution was injected into the apparatus, and chromatograms were obtained at a column oven temperature of 40°C and a THF flow rate of 0.5 ml/min. The columns were sequentially connected to Agilent Zorbax PSM-1000S, PSM-300S, and PSM-60S, with a DIOL 4.6 × 12.5 mm 5 micron column connected upstream as a guard column. <Calculation Method for Modification Rate>: For the chromatogram using a polystyrene-based column, set the entire peak area to 100. Set the peak area of the sample as p1, and the peak area of standard polystyrene as p2. For the chromatogram using a silicon dioxide-based column, set the entire peak area to 100, and the peak area of the sample as p3. Set the peak area of standard polystyrene as p4. Calculate the modification rate (%) using the following formula: Modification Rate (%) = [1 - (p2 × p3) / (p1 × p4)] × 100 (where p1 + p2 = p3 + p4 = 100)

(Physical Property 8) Branching Degree (Bn) was determined using the GPC-light scattering method with a viscosity detector, as described below. The modified conjugated diene polymer was used as a sample. A GPC measuring apparatus (manufactured by Malvern, trade name "GPCmax VE-2001") was used, consisting of three columns containing polystyrene gel as filler. Three detectors (manufactured by Malvern, trade name "TDA305") were connected sequentially for measurement. Based on standard polystyrene, the absolute molecular weight was determined from the results of the light scattering and RI detectors, and the intrinsic viscosity was determined from the results of the RI and viscosity detectors. The shrinkage factor (g') of the linear polymer was calculated as the ratio of the intrinsic viscosity to the intrinsic viscosity of each molecular weight, based on the intrinsic viscosity [ _η0 ] = ^10⁻³.498 M ^0.711 . In the above formula, M is the absolute molecular weight. The dissolution solution used was THF containing 5 mmol/L triethylamine. The columns were connected to Tosoh's trade names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL". 20 mg of the test sample was dissolved in 10 mL of THF to prepare the test solution. 100 μL of the test solution was injected into the GPC assay apparatus, and the determination 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 measurements, and the branching degree (Bn) was calculated using the shrinkage factor (g'), which is defined as g' = 6Bn/{(Bn+1)(Bn+2)}.

(Property 9) Height of the 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. Methanol was then added to the solution, and the precipitate was completely dried using a vacuum dryer at 40°C. The dried polymer was then pressurized 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 torsional mode, the tanδ corresponding to temperatures within the range of -100℃ to 100℃ was measured at a frequency of 10 Hz, a strain rate of 0.5%, and a heating rate of 5℃/min. The results were plotted with temperature on the horizontal axis and tanδ on the vertical axis, and the tanδ value at the maximum point was set as the height of the tanδ peak.

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

[Preparation of Modified Conjugated Diene Polymers] (Example 1) Two trough-type pressure vessels are connected as polymerization reactors. The trough-type pressure vessels have an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom, an outlet at the top, and a stirrer and a jacket for temperature control, serving as a stirrer for the trough-type reactor. Pre-dehydrated 1,3-butadiene is mixed at 17.4 g/min, styrene is mixed at 5.8 g/min, and n-hexane is mixed at 180.1 g/min to obtain a mixed solution. In a static mixer located midway through the piping supplying the mixed solution to the inlet of the reactants, n-butyllithium for inert treatment of residual impurities was added at 0.104 mmol/min and mixed, then continuously supplied to the bottom of the reactants. Subsequently, 2,2-bis(2-tetrahydrofuranyl)propane as a polar substance was supplied to the bottom of the first reactor, which was being vigorously mixed using a stirrer, at a rate of 0.034 mmol/min, and n-butyllithium as a polymerization initiator was supplied at a rate of 0.203 mmol/min, while maintaining the reactor temperature at 82°C. When the polymerization reaction stabilized, a small amount of 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 segment, the amount of vinyl bonds in the bonded conjugated diene ( _Y1 ), the conversion rate c, and the styrene conversion rate _cst were determined.

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

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.

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, thus ending the coupling reaction. Subsequently, 25 phr of S-RAE oil (manufactured by JX Nippon Oil & Energy Co., Ltd., trade name "Process NC140") was added as a plasticizer, and the mixture was stirred. The solvent was removed by steam stripping to obtain a modified conjugated diene polymer (A1), which was then used to determine various physical properties.

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

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

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

(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.

(Example 6) Except that the amount of n-butyllithium supplied as a polymerization initiator in the first reactor was changed to 0.167 mmol/min, the amount of polar substance was changed to 0.029 mmol/min, the amount of polar substance added to the second reactor was changed to 0.107 mmol/min, no branching agent was added, and the amount of coupling modifier was changed to 0.023 mmol/min, the modified conjugated diene polymer of Example 6 was obtained in the same manner as in Example 4.

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

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

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

(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.

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

(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.

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

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

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

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

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

(Comparative Example 1) Except that the 1,3-butadiene supplied to the first reactor was changed to 17.8 g/min, the styrene was changed to 8.0 g/min, the n-hexane was changed to 180.3 g/min, the polar substance was changed to 0.045 mmol/min, the reaction temperature of the first polymerization reactor was changed to 65°C, no styrene and polar substance were added to the second reactor, the 1,3-butadiene added to the second reactor was changed to 7.6 g/min, the n-hexane was changed to 42.8 g/min, and the reaction temperature of the second polymerization reactor was changed to 90°C, the modified conjugated diene polymer of Comparative Example 1 was obtained in the same manner as in Example 1.

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

(Comparative Example 3) The n-butyllithium used as a polymerization initiator in the first reactor was changed to 0.104 mmol/min, the polar substance was changed to 0.025 mmol/min, no branching agent was added in the second reactor, and the coupling modifier was changed to 0.016 mmol/min. The modified conjugated diene polymer of Comparative Example 3 was obtained in the same manner as Comparative Example 1.

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

(Comparative Example 5) Except that the amount of n-butyllithium supplied as a polymerization initiator in the first reactor was changed to 0.250 mmol/min, the amount of 1,3-butadiene was changed to 19.8 g/min, the amount of styrene was changed to 5.1 g/min, the amount of n-hexane was changed to 146.7 g/min, the amount of polar substance was changed to 0.008 mmol/min, the reaction temperature of the first polymerization reactor was changed to 60°C, the amount of 1,3-butadiene added to the second reactor was changed to 8.5 g/min, the amount of n-hexane was changed to 42.1 g/min, and the amount of polar substance was changed to 0.109 mmol/min. The reaction temperature of the second polymerization reactor was changed to 60°C without the addition of a branching agent. N,N-dimethyl-3-(trimethoxysilyl)propane-1-amine (coupling modifier B in the table) was replaced with 0.047 mmol/min as the coupling modifier A. Except for the addition of a plasticizer, the modified conjugated diene polymer of Comparative Example 4 was obtained in the same manner as Comparative Example 1.

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

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

(Comparative Example 8) Except that the amount of n-butyllithium supplied as a polymerization initiator in the first reactor was changed to 0.250 mmol/min, the amount of 1,3-butadiene was changed to 18.4 g/min, the amount of styrene was changed to 5.8 g/min, the amount of n-hexane was changed to 146.3 g/min, the amount of polar substance was changed to 0.011 mmol/min, the reaction temperature of the first polymerization reactor was changed to 60°C, the amount of 1,3-butadiene added to the second reactor was changed to 10.2 g/min, the amount of n-hexane was changed to 50.6 g/min, and the amount of polar substance was changed to 0.109 mmol/min. The reaction temperature of the second polymerization reactor was changed to 60°C without the addition of a branching agent. The reaction rate of bis(3-(diethoxymethylsilylpropyl)-N-methylamine (coupling modifier C in the table) was changed to 0.053 mmol/min to replace A as the coupling modifier. Except for the addition of a plasticizer, the modified conjugated diene polymer of Comparative Example 8 was obtained in the same manner as Comparative Example 1.

(Comparative Example 9) A 20 L tank-type polymerization reactor with a stirring device was used for batch polymerization 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, in order to pre-detoxify impurities that inactivate the polymerization initiator, a small amount of n-butyllithium hexane solution was added to the polymerization reactor as a scavenging agent, followed by the addition of a n-hexane solution containing 3.12 mmol of BuLi to the polymerization reactor to start the polymerization reaction. The polymerization reaction was carried out for 4 hours and 10 minutes. In the polymerization reaction, the temperature inside the reactor was adjusted to 65°C, and the solution inside the reactor was stirred at 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 reactor for 3 hours and 20 minutes. Then, while maintaining the reactor temperature at 65°C, the obtained polymerization solution was stirred at 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 reactor, and the polymerization solution was stirred for 5 minutes. Subsequently, 0.3 parts by weight of antioxidant (BHT) was added as a stabilizer for every 100 parts by weight of polymer to obtain the conjugated diene polymer of Comparative Example 9.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Examples 18-34] and [Comparative Examples 10-18] The modified conjugated diene polymers of the embodiments and comparative examples shown in Tables 1-4 above were used as raw rubbers, and rubber compositions containing each raw rubber were obtained according to the composition shown below. Modified conjugated diene polymers (Examples 1-17, Comparative Examples 1-9): 100 parts by weight (oil removed); Silica (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, trade 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 Mining & Energy Co., trade name "Process Oil"): 6.8 parts by weight. 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 part by weight; Vulcanization accelerator 1: Tetrabenzylthiuram disulfide: 0.5 parts by weight; Vulcanization accelerator 2: N-(tributyl)-2-benzothiazolylsulfinamide: 2.5 parts by weight; Total: 246.95 parts by weight

Rubber compounds were obtained by mixing the above materials using the following method. A closed mixer (0.3 L capacity) equipped with a temperature control device was used as the first stage of mixing. Under conditions of 65% filler and rotor speed of 30–50 rpm, the raw rubber, fillers (silica, carbon black), silane coupling agent, processing oil, zinc oxide, and stearic acid were mixed. The temperature of the closed mixer was controlled, and the rubber compounds (formulations) were obtained at an outlet temperature of 145–150°C.

Secondly, as the second stage of mixing, the obtained compound is cooled to room temperature, and an anti-aging agent is added. To improve the dispersion of silica, the compound is mixed again. In this case, the discharge temperature of the compound is 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, molding is performed, and vulcanization is carried out at 160°C using a vulcanizing press for 20 minutes. The rubber compound before vulcanization and the rubber compound after vulcanization are evaluated. Specifically, the evaluation is carried out using the following methods.

[Evaluation 1, Evaluation 2: Viscoelastic Parameters] Viscoelastic parameters were measured in torsion mode using an ARES viscoelastic testing machine manufactured by Rheometrics Scientific. Each measured value was exponentially converted to the result of the rubber composition of Comparative Example 10 as 100.

(Evaluation 1: Fuel-saving performance) The tanδ value, measured at 50°C with a frequency of 10 Hz and a strain of 1%, is set as the indicator of fuel-saving performance. The higher the index, the better the fuel-saving performance. An index value of 85 or above is considered to indicate good fuel-saving performance as a sulfide.

(Evaluation 2: Wet Grip Performance) The tanδ value, measured at 0°C with a frequency of 10 Hz and a strain of 1%, is set as the indicator of wet grip performance. The higher the index, the better the wet grip performance. When the index value is above 90, it is judged that it has good fuel-saving performance as a sulfide.

[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 abrasion resistance.

[Evaluation 4: Tensile Properties] Tensile strength and elongation were measured according to the tensile test method of JIS K6251. The product of these properties was indexed by setting the result of Comparative Example 10 to 100. A larger index indicates better tensile strength and elongation (breaking strength). An index value of 85 or higher is considered sufficient for a sulfide to have adequate tensile properties.

[Evaluation 5: Processability] Regarding the uncured modified conjugated diene polymers produced 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 evaluated by each functional inspector on a scale of 5 based on the following criteria. Cohesiveness is an indicator of the processability of the sulfide. A higher index indicates better processability. <Evaluation Criteria> 1: Less than 50% of the sheet edge is relatively smooth, indicating very poor processability. 2: More than 50% but less than 60% of the sheet edge is relatively smooth, indicating poor processability. 3: More than 60% but less than 80% of the sheet edge is relatively smooth, indicating good processability. 4. Over 80% to 90% of the sheet edges are relatively smooth, resulting in excellent processability. 5. Over 90% of the sheet edges are relatively smooth, resulting in very excellent processability.

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

[Table 5] Implementation Example 18 Implementation Example 19 Implementation Example 20 Implementation Example 21 Implementation Example 22 Implementation Example 23 The modified conjugated diene polymer used Implementation Example 1 Implementation Example 2 Implementation Example 3 Implementation Example 4 Implementation Example 5 Implementation Example 6 (Evaluation 1) Fuel efficiency 98 98 98 98 94 92 (Evaluation 2) Wet 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

[Table 6] Implementation Example 24 Implementation Example 25 Implementation Example 26 Implementation Example 27 Implementation Example 28 The modified conjugated diene polymer used Implementation Example 7 Implementation Example 8 Implementation Example 9 Implementation Example 10 Implementation Example 11 (Evaluation 1) Fuel efficiency 102 98 98 105 108 (Evaluation 2) Wet 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

[Table 7] Implementation Example 29 Implementation Example 30 Implementation Example 31 Implementation Example 32 Implementation Example 33 Implementation Example 34 The modified conjugated diene polymer used Implementation Example 12 Implementation Example 13 Implementation Example 14 Implementation Example 15 Implementation Example 16 Implementation Example 17 (Evaluation 1) Fuel efficiency 92 88 98 98 94 97 (Evaluation 2) Wet 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

[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 efficiency 100 110 93 83 80 110 108 81 43 (Evaluation 2) Wet 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

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

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 (10)

A modified conyodene polymer comprising conyodene monomers and aromatic vinyl monomers, with a weight-average molecular weight of 700,000 or more as determined by GPC and a modification rate of 60% or more, exhibits a tanδ peak in the temperature range of -100°C to 100°C in a tanδ peak diagram corresponding to temperature obtained by dynamic viscoelastic analysis using ARES (Advanced Rheometric Expansion System) based on the following <Condition 1>. The tanδ peak has a height of 0.90 or more and 1.45 or less. <Condition 1> The tanδ peak diagram was obtained by measuring the properties of a tanδ 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. For example, the modified conjugated diene polymer of claim 1, wherein the branching degree (Bn) measured by the GPC-light scattering method of the viscosity detector is 7 or above. The modified conjugated diene polymer of claim 1 has a molecular weight distribution of 1.7 or more and 2.5 or less. For example, the modified conjugated diene polymer of claim 1, wherein the estimated glass transition temperature (estimated Tg) of the microstructure derived from the modified conjugated diene polymer is above -62°C and below -25°C. The modified conjugated diene polymer of claim 1 has two or more polymer segments, and the mass fraction of the modified conjugated diene polymer is 10% or more. The estimated glass transition temperature (estimated Tg) of the first polymer segment, which is the polymer segment closest to the starting end, is -90°C or higher and -40°C or lower. The estimated Tg of the second polymer segment, which is the polymer segment closest to the ending end, is -50°C or higher and -10°C or lower, and is higher than the estimated Tg of the first polymer segment. The modifier is bonded to the end of the second polymer segment. The modified conjugated diene polymer of claim 1 has a modifier residue derived from an alkoxysilane compound having a nitrogen atom. A method for manufacturing a modified conjugated diene polymer, which is the method for manufacturing a conjugated diene polymer as described in any one of claims 1 to 6, and includes a polymerization step: 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, wherein the continuous reactor has a monomer addition section, which adds at least one conjugated diene compound and an aromatic vinyl compound during the polymerization step; and the manufacturing method includes a coupling step: reacting the conjugated diene polymer obtained by the polymerization step with a modifier having nitrogen atoms. For example, in the method for manufacturing modified conjugated diene polymers as claimed in claim 7, an aromatic vinyl compound is used as a polymerizing monomer in the above-mentioned polymerization step, and the conversion rate of the aromatic vinyl compound in the polymerization intermediate in the monomer addition section is 70% or more. As in the method for manufacturing the modified conjugated diene polymer of claim 7, the location of the monomer addition section is between the piping of the first reactor and the second reactor in the continuous reactor. The method for manufacturing modified conjugated diene polymers, as described in claim 7, wherein a branching agent is added to the above-mentioned monomer addition section.