Hydrogenated conjugated diene-based polymer, and production method of hydrogenated conjugated diene-based polymer

Abstract

To provide a hydrogenated conjugated diene-based polymer which is excellent in fuel-saving performance of a rubber composition, wet grip performance, and a balance between tensile strength and tensile elongation without impairing workability in preparing a rubber composition.SOLUTION: There is provided a hydrogenated conjugated diene-based polymer, in which a Mooney viscosity change rate (ΔML) represented by the following formula (1) is 1% or more and 40% or less, a peak shape obtained from a molecular weight distribution curve in GPC measurement is unimodal, and a hydrogenation rate is 10% or more and 100% or less. ΔML=[(MLf-MLi) / MLi]×100...(1) (In the formula (1), ΔML is a Mooney viscosity change rate, MLf is a Mooney viscosity at 100°C after the hydrogenated conjugated diene-based polymer is left at 25°C for 90 days, and MLi is an initial Mooney viscosity at 100°C of the hydrogenated conjugated diene-based polymer.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hydrogenated conjugated diene polymer and a method for producing a hydrogenated conjugated diene polymer. [Background technology]

[0002] In recent years, with the demand for improved fuel economy in automobiles, there has been a demand for conjugated diene polymers for use in rubber compositions for tires that have an excellent balance between fuel-saving performance and wet grip performance, as well as excellent abrasion resistance and strength properties.

[0003] To improve the balance between fuel economy and wet grip performance, it has become common to use modified conjugated diene polymers in rubber compositions for tires. On the other hand, to improve the abrasion resistance of a rubber composition using a modified conjugated diene polymer, it is necessary to increase the molecular weight of the modified conjugated diene polymer. However, increasing the molecular weight leads to problems such as an increase in the solution viscosity and melt viscosity of the polymer, a decrease in productivity due to the generation of powder during drying, and a decrease in processability during preparation of the rubber composition. To solve these problems, Patent Document 1 below proposes a technology for improving the balance between increasing the molecular weight of a modified conjugated diene polymer and processability during compound preparation by controlling the branching degree of the modified conjugated diene polymer.

[0004] Furthermore, it has been known that when a large amount of modifier is added to a modified conjugated diene polymer, the viscosity increases over time due to condensation between residues of reactive groups in the modified conjugated diene polymer, etc. If the viscosity of the modified conjugated diene polymer increases significantly after production, it becomes difficult to ensure good quality for practical use, and processability when producing a rubber composition tends to deteriorate significantly. In view of such problems, Patent Documents 2 and 3 propose techniques for preventing viscosity changes from occurring after the production of modified conjugated diene polymers. Furthermore, Patent Document 4 proposes a conjugated diene polymer using a specific hydrogenation technique in order to improve the tensile strength of a rubber composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-28047 [Patent Document 2] International Publication No. 2018 / 025998 [Patent Document 3] International Publication No. 2021 / 049909 [Patent Document 4] International Publication No. 2021 / 206068 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as in the above-mentioned conventional technology, even if the tensile strength and abrasion resistance of the rubber composition are improved by highly branching and increasing the molecular weight of the modified conjugated diene polymer, there is still a problem that there is room for improvement in processability. Furthermore, when the balance between fuel economy performance and wet grip performance or the tensile properties of the rubber composition is improved by increasing the amount of modifier added, the viscosity tends to increase significantly, and there is still room for improvement from the viewpoint of ensuring sufficient quality for practical use, and there is also the problem that processability deteriorates. Furthermore, when the molecular weight of the modified conjugated diene polymer is reduced in an attempt to improve processability, although the processability of the rubber composition can be improved, the tensile strength deteriorates. Furthermore, when a technique for suppressing viscosity increase after production of a modified conjugated diene-based polymer is used, there is a problem that there is room for improvement in terms of the balance between fuel-saving performance and wet grip performance of the rubber composition, tensile strength, and abrasion resistance.

[0007] In view of the above-mentioned problems of the conventional art, the present invention aims to provide a hydrogenated conjugated diene-based polymer that provides a rubber composition with an excellent balance of fuel-saving performance, wet grip performance, tensile strength, and tensile elongation without impairing processability during preparation of the rubber composition. [Means for solving the problem]

[0008] As a result of extensive research into solving the problems of the prior art described above, the present inventors have completed the present invention by designing a hydrogenated conjugated diene polymer having a specific structure. That is, the present invention is as follows.

[0009] [1] The Mooney viscosity change rate (ΔML) represented by the following formula (1) is 1% or more and 40% or less, The peak shape obtained from the molecular weight distribution curve in GPC measurement is unimodal, The hydrogenation rate is between 10% and 100%. Hydrogenated conjugated diene polymer. ΔML=[(ML f -ML i ) / ML i ]×100 (1) (In the above formula (1), ΔML is the rate of change in Mooney viscosity, and ML f is the Mooney viscosity at 100°C after leaving the hydrogenated conjugated diene polymer at 25°C for 90 days, and ML i is the initial Mooney viscosity of the hydrogenated conjugated diene polymer at 100°C. [2] The hydrogenated conjugated diene polymer has a nitrogen atom content of 20 ppm or more. The hydrogenated conjugated diene polymer according to [1] above. [3] The hydrogenated conjugated diene polymer has a silicon atom content of 20 ppm or more. The hydrogenated conjugated diene polymer according to [1] or [2] above. [4] The hydrogenated conjugated diene polymer according to any one of [1] to [3] above, wherein (nitrogen atom content of the hydrogenated conjugated diene polymer) / (silicon atom content of the hydrogenated conjugated diene polymer) is 0.75 or more. [5] The weight average molecular weight of the hydrogenated conjugated diene polymer is 100,000 or more and 2,000,000 or less. The hydrogenated conjugated diene polymer according to any one of [1] to [4] above. [6] In the formula (1), the initial Mooney viscosity (ML i ) is 30 or more and 200 or less. [7] the molecular weight distribution of the hydrogenated conjugated diene polymer as measured by GPC is less than 1.7; The hydrogenated conjugated diene polymer according to any one of [1] to [6] above. [8] The butylene content of the hydrogenated conjugated diene polymer is 10 mol% or more and 60 mol% or less. The hydrogenated conjugated diene polymer according to any one of [1] to [7] above. [9] The molecular weight distribution change rate (ΔPDI) represented by the following formula (2) is 2% or more and 30% or less. The hydrogenated conjugated diene polymer according to any one of [1] to [8] above. ΔPDI(%)=[|(PDI f -PDI i )| / PDI i ]×100 (2) (In equation (2), ΔPDI is the rate of change in molecular weight distribution, and PDI i is the molecular weight distribution of the hydrogenated conjugated diene polymer immediately after polymerization, and PDI f is the molecular weight distribution of the hydrogenated conjugated diene polymer after standing at 25°C for 90 days.

[10] The hydrogenated conjugated diene polymer according to any one of [1] to [9] above, which has a graft chain derived from a macromonomer containing a repeating unit derived from an N-functional group-containing compound.

[11] A method for producing the hydrogenated conjugated diene polymer according to any one of [1] to

[10] , a polymerization step of polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer before modification; a modification step of reacting the unmodified conjugated diene polymer with an alkoxysilane compound to produce a modified conjugated diene polymer; a reaction step of reacting the modified conjugated diene polymer with a macromonomer containing a repeating unit derived from an N-functional group-containing compound; a hydrogenation step of reacting with hydrogen to obtain a hydrogenated conjugated diene-based polymer after the reaction step, A method for producing a hydrogenated conjugated diene polymer.

[12] A method for producing the hydrogenated conjugated diene polymer according to any one of [1] to

[10] , a polymerization step of polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer before modification; a modification step of reacting the unmodified conjugated diene polymer with an alkoxysilane compound to produce a modified conjugated diene polymer; a reaction step of reacting the modified conjugated diene-based polymer with an alkyllithium compound or a reaction product of an alkyllithium compound and an N-functional group-containing compound; a hydrogenation step of reacting with hydrogen to obtain a hydrogenated conjugated diene-based polymer after the reaction step, A method for producing a hydrogenated conjugated diene polymer. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a hydrogenated conjugated diene polymer that provides a rubber composition with an excellent balance of fuel-saving performance, wet grip performance, tensile strength, and tensile elongation without impairing processability during preparation of the rubber composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to these. That is, the present invention can be implemented by making any modifications within the scope of the gist of the present invention.

[0012] In this specification, when "~" is used to express a numerical value or a physical property value, the values ​​before and after the "~" are included. In this specification, the term "compound" refers to a compound before polymerization, and the term "monomer unit" refers to a structural unit that constitutes a polymer. In addition, in this specification, the term "conjugated diene polymer" refers to a polymer in an unhydrogenated state, and the term "hydrogenated conjugated diene polymer" refers to a hydrogenated polymer.

[0013] [Hydrogenated conjugated diene polymer] The hydrogenated conjugated diene polymer of this embodiment is The Mooney viscosity change rate (ΔML) represented by the following formula (1) is 1% or more and 40% or less, The peak shape obtained from the molecular weight distribution curve in GPC measurement is unimodal, The hydrogenation rate is between 10% and 100%. ΔML=[(ML f -ML i ) / ML i ]×100 (1) (In the above formula (1), ΔML is the rate of change in Mooney viscosity, and ML f is the Mooney viscosity at 100°C after leaving the hydrogenated conjugated diene polymer at 25°C for 90 days, and ML i is the initial Mooney viscosity of the hydrogenated conjugated diene polymer at 100°C.

[0014] According to the above-mentioned configuration, a hydrogenated conjugated diene polymer having an excellent balance of fuel-saving performance, wet grip performance, tensile strength and tensile elongation of the rubber composition can be obtained without impairing processability during preparation of the rubber composition.

[0015] The hydrogenated conjugated diene polymer of this embodiment can be obtained by hydrogenating a polymer containing a conjugated diene compound. Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of effectively and reliably achieving the effects of the present embodiment. These conjugated diene compounds may be used alone or in combination of two or more.

[0016] The hydrogenated conjugated diene polymer of the present embodiment may contain a monomer unit other than a conjugated diene monomer unit, and preferably contains, for example, a monomer unit derived from an aromatic vinyl compound.

[0017] Examples of aromatic vinyl compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of effectively and reliably achieving the effects of the present embodiment. These aromatic vinyl compounds may be used alone or in combination of two or more.

[0018] Furthermore, the hydrogenated conjugated diene polymer of the present embodiment is preferably a hydrogenated product of a polymer of only a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound (hereinafter also referred to as a "conjugated diene-aromatic vinyl copolymer").

[0019] (Aromatic vinyl monomer unit content) From the viewpoint of the tensile strength of the rubber composition, the hydrogenated conjugated diene polymer of this embodiment preferably contains an aromatic vinyl monomer unit. The content of the aromatic vinyl monomer unit is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and even more preferably 6 parts by mass or more. On the other hand, from the viewpoint of the ease of pulverizing a molded product of the hydrogenated conjugated diene polymer, the content is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less. The content of the aromatic vinyl monomer unit in the hydrogenated conjugated diene polymer of this embodiment can be controlled by adjusting the amount of the aromatic vinyl compound added during polymerization. The content of the aromatic vinyl monomer unit is determined by the formula shown in the Examples below. 1 It can be measured by H-NMR.

[0020] (Aromatic vinyl monomer block content) Furthermore, from the viewpoint of the abrasion resistance of the rubber composition, the content of the aromatic vinyl monomer block in the hydrogenated conjugated diene polymer of this embodiment is preferably less than 5.0 mass%, more preferably 4.0 mass% or less, even more preferably 3.5 mass% or less, even more preferably 3.0 mass% or less, and even more preferably 2.0 mass% or less. In this specification, the term "aromatic vinyl monomer block" refers to a structure in which eight or more aromatic vinyl monomer units are linked together. The method for measuring the content of the aromatic vinyl monomer block is not particularly limited, and examples thereof include known methods such as measuring the chain of styrene units using NMR, as described in International Publication No. 2014 / 133097. Another method includes a method in which a conjugated diene polymer before hydrogenation is used as a sample, the polymer is decomposed by the Kolthoff method (the method described in I. M. Kolthoff, et al., J. Polym. Sci. 1, 429 (1946)), and the amount of polystyrene insoluble in methanol is analyzed.

[0021] (hydrogenation rate) The hydrogenation rate of the hydrogenated conjugated diene polymer of this embodiment is 10% or more, preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and even more preferably 50% or more, from the viewpoint of the heat resistance and ozone resistance of the rubber composition. On the other hand, from the viewpoint of ease of vulcanization and processability of the rubber composition, it is 100% or less, preferably 99% or less, more preferably 98% or less, even more preferably 95% or less, even more preferably less than 90%, and even more preferably less than 85%. The hydrogenation rate of a hydrogenated conjugated diene polymer is the proportion (molar ratio) of double bonds in the structure derived from conjugated diene monomer units that have become saturated bonds through a hydrogenation reaction. The hydrogenation rate can be controlled within the above range by adjusting the amount of hydrogen added, the reaction temperature, the reaction time, the type of catalyst, and the amount of catalyst added. The hydrogenation rate is as described in the examples below. 1 It can be measured by H-NMR.

[0022] (hydrogenation reaction) The hydrogenated conjugated diene polymer of this embodiment can be obtained, for example, by hydrogenating (adding hydrogen to) the conjugated diene moiety. The method for hydrogenating the conjugated diene portion of the conjugated diene polymer is not particularly limited, and known methods can be used. For example, as described in WO 96 / 05250, JP 2000-053706, WO 2003 / 085010, WO 2019 / 151126, WO 2019 / 151127, WO 2002 / 002663, and WO 2015 / 006179, a preferred method is to polymerize a conjugated diene compound by anionic polymerization under various additives and conditions, copolymerize it with other compounds as needed, and then hydrogenate the resulting polymer. The hydrogenation reaction may be carried out by either a batch process or a continuous process, or by a combination of these. The temperature of the hydrogenation reaction is not particularly limited, but is preferably 60 to 105°C, and more preferably 70 to 100°C.

[0023] (vinyl bond content, butylene content) In the hydrogenated conjugated diene polymer of this embodiment, the 1,2-vinyl bond content of the conjugated diene polymer before hydrogenation refers to the molar ratio of 1,2-vinyl bonds in the conjugated diene monomer units. From the viewpoint of the tensile properties of the rubber composition, the 1,2-vinyl bond content is preferably 65 mol% or less, more preferably 60 mol% or less, and even more preferably 58 mol% or less. On the other hand, from the viewpoint of the flexibility and chipping suppression of the rubber composition, the 1,2-vinyl bond content is preferably 18 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more. The butylene content of the hydrogenated conjugated diene polymer of this embodiment is preferably the content of a structure in which 1,2-vinyl bonds of the conjugated diene polymer are hydrogenated. The butylene content is expressed as a molar ratio in the conjugated diene monomer units in the hydrogenated conjugated diene polymer. From the viewpoint of improving the heat resistance of the rubber composition, the butylene content is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and even more preferably 25 mol% or more. On the other hand, from the viewpoint of reducing the hardness of the rubber composition, the butylene content is preferably 60 mol% or less, more preferably 55 mol% or less, even more preferably 50 mol% or less, and even more preferably 45 mol% or less. The 1,2-vinyl bond amount and butylene content can be controlled within the above-mentioned ranges by adjusting the polymerization temperature during polymerization and the amount of the polar compound to be described later. The 1,2-vinyl bond amount of the conjugated diene polymer before hydrogenation was measured by using the conjugated diene polymer before hydrogenation as a measurement sample. 1 The butylene content of the hydrogenated conjugated diene polymer can be measured by H-NMR. 1 It can be measured by H-NMR.

[0024] (Weight average molecular weight) The weight-average molecular weight (Mw) of the hydrogenated conjugated diene polymer of this embodiment is preferably 100,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and even more preferably 300,000 or more, from the viewpoint of suppressing adhesion. On the other hand, from the viewpoint of processability and bale formability, it is preferably 2,000,000 or less, more preferably 1,800,000 or less, even more preferably 1,500,000 or less, and particularly preferably 1,300,000 or less. The weight average molecular weight (Mw) can be controlled within the above range, for example, by adjusting the amount of polymerization initiator used and the type and amount of modifier added, which will be described later. The weight average molecular weight (Mw) of the hydrogenated conjugated diene polymer of this embodiment can be measured by GPC (gel permeation chromatography). Specifically, it can be measured by the method described in the examples below.

[0025] (Mooney viscosity) The initial Mooney viscosity at 100°C of the hydrogenated conjugated diene polymer of this embodiment is preferably 30 or more, more preferably 40 or more, even more preferably 45 or more, and even more preferably 50 or more, from the viewpoint of cold flow performance. On the other hand, from the viewpoint of bale moldability and processability during rubber composition preparation, the Mooney viscosity is preferably 180 or less, more preferably 160 or less, even more preferably 150 or less, and even more preferably 140 or less. The initial Mooney viscosity of the hydrogenated conjugated diene polymer refers to the Mooney viscosity immediately after polymerization, and can be measured using an L-type rotor, specifically by the method described in the examples below.

[0026] (Mooney viscosity change rate) The hydrogenated conjugated diene polymer of this embodiment has a Mooney viscosity change rate represented by the following formula (1) of 1% or more and 40% or less. ΔML=[(ML f -ML i ) / ML i ]×100 (1) In the formula (1), ΔML is the rate of change in Mooney viscosity, and ML f is the Mooney viscosity at 100°C after leaving the hydrogenated conjugated diene polymer at 25°C for 90 days, and MLi is the initial Mooney viscosity of the hydrogenated conjugated diene polymer at 100°C. The rate of change in Mooney viscosity represented by the formula (1) is 40% or less, preferably 30% or less, more preferably 20% or less, even more preferably 15% or less, and even more preferably 10% or less, from the viewpoints of productivity and quality assurance, while being 1% or more, preferably 2% or more, more preferably 3% or more, even more preferably 4% or more, and even more preferably 5% or more, from the viewpoint of improving the balance between the tensile strength and tensile elongation of the rubber composition.

[0027] The Mooney viscosity of the hydrogenated conjugated diene polymer of this embodiment can be measured by the method described in the examples below. The Mooney viscosity at 100°C of the hydrogenated conjugated diene polymer can be controlled, for example, by adjusting the molecular weight of the conjugated diene polymer, the hydrogenation rate, etc. Specifically, when the weight average molecular weight Mw is 200,000 or more and 1,000,000 or less, the Mooney viscosity tends to be controlled within the above range. Furthermore, since the Mooney viscosity tends to increase as the hydrogenation rate increases, when the hydrogenation rate is 70% or higher, it is preferable to set the weight average molecular weight Mw to 100,000 or more and 500,000 or less, and when the hydrogenation rate is 50% or less, it is preferable to set the weight average molecular weight Mw to 200,000 or more and 800,000 or less. The rate of change in Mooney viscosity of the hydrogenated conjugated diene polymer of this embodiment, represented by the formula (1), can be controlled within the above-mentioned range by adjusting the amount of coupling agent or modifier added, which will be described later, the reactive group content after the coupling reaction or modification reaction, whether or not neutralization is performed during the production process, and the pH.

[0028] (GPC peak number, molecular weight distribution) The hydrogenated conjugated diene polymer of this embodiment has a single peak in the molecular weight distribution curve obtained by GPC measurement, from the viewpoint of the processability, tensile properties, and abrasion resistance of the rubber composition. Here, unimodal means that the number of peaks is one. If the number of peaks is two or more, the balance between the processability, tensile properties, and abrasion resistance of the rubber composition tends to be poorer than when the number of peaks is one. A peak obtained by GPC measurement is one that has an area of ​​3.0% or more when the total area of ​​the molecular weight distribution curve obtained by GPC measurement is taken as 100% and has a peak top. The peak top is a point at which the maximum value is sandwiched between the baseline or minimum values.

[0029] The molecular weight distribution of the hydrogenated conjugated diene polymer of this embodiment is preferably less than 1.7, more preferably less than 1.65, even more preferably less than 1.6, and even more preferably less than 1.5, from the viewpoint of improving processability and polymerization reproducibility, while being preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more, from the viewpoint of reducing the polymer viscosity as much as possible and improving the abrasion resistance of the rubber composition.

[0030] Furthermore, in the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of the abrasion resistance of the rubber composition, the content of components having a molecular weight of 1 million or more is preferably 1% or more, more preferably 2% or more, and more preferably 3% or more, while from the viewpoint of the processability of the rubber composition, the content is preferably 30% or less, more preferably 20% or less, and even more preferably 15% or less.

[0031] The number of peaks in the molecular weight distribution curve obtained by GPC measurement, the molecular weight distribution, and the content of components with a molecular weight of 1,000,000 or more can be controlled by adjusting the polymerization method (batch polymerization or continuous polymerization), the polymerization temperature, the amount of polar substance added during the polymerization reaction, and the type and amount of additives (such as coupling agents and modifiers). For example, continuous polymerization tends to produce broader molecular weight distributions than batch polymerization, and it is easier to control the peak shape of the molecular weight distribution curve obtained by GPC measurement to a single peak. Furthermore, the molecular weight distribution tends to be broader when the polymerization temperature is higher or when a coupling agent or modifier is added. To achieve a molecular weight distribution of less than 1.7 using a continuous polymerization method, it is preferable to maintain the polymerization temperature at 90°C or less from the start to the end of polymerization.

[0032] (Molecular weight distribution change rate) Furthermore, the hydrogenated conjugated diene polymer of this embodiment preferably has a molecular weight distribution change rate represented by the following formula (2) of 2% or more and 30% or less. ΔPDI(%)=[|(PDI f -PDI i )| / PDI i ]×100···(2) In the formula (2), ΔPDI is the rate of change in molecular weight distribution, and PDI i is the molecular weight distribution of the hydrogenated conjugated diene polymer immediately after polymerization, and PDI f is the molecular weight distribution of the hydrogenated conjugated diene polymer after being left at 25°C for 90 days.

[0033] The lower limit of the rate of change in molecular weight distribution is preferably 2% or more, more preferably 4% or more, and even more preferably 6% or more, from the viewpoint of the balance between productivity and the tensile strength and tensile elongation of the rubber composition, while from the viewpoint of the processability and quality assurance of the rubber composition, it is preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, and even more preferably 15% or less. A suitable method for keeping the rate of change in molecular weight distribution in formula (2) within the above range is to adjust the amount of a coupling agent or modifier added, as described below, to control the nitrogen content or silicon content to a certain amount or more.

[0034] (Silicon atom content) From the viewpoint of improving the dispersibility of silica, the hydrogenated conjugated diene polymer of this embodiment has a silicon atom content of preferably 20 ppm or more, more preferably 50 ppm or more, even more preferably 60 ppm or more, even more preferably 70 ppm or more, and even more preferably 80 ppm or more. On the other hand, from the viewpoint of the processability of the rubber composition, the silicon atom content is preferably 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less. The silicon atom content can be controlled within the above range, for example, by adjusting the amount and type of coupling agent or modifier having a nitrogen atom-containing group, which will be described later.

[0035] (titanium content, aluminum content) When titanium is used as a hydrogenation catalyst component in producing the hydrogenated conjugated diene polymer of this embodiment, the amount of titanium added is preferably 150 ppm or less based on the conjugated diene polymer before hydrogenation. The titanium content of the hydrogenated conjugated diene polymer is preferably 1 ppm or more and 100 ppm or less, more preferably 5 ppm or more and 90 ppm or less, and even more preferably 10 ppm or more and 80 ppm or less. A titanium content of 100 ppm or less can prevent yellowing of the hydrogenated conjugated diene polymer, and a titanium content of 1 ppm or more can eliminate the need for removal equipment, thereby reducing costs. When aluminum is used as a hydrogenation catalyst component in producing the hydrogenated conjugated diene polymer of this embodiment, the amount of aluminum added is preferably 6 ppm or less, more preferably 3 ppm or less, and even more preferably no aluminum is added, relative to the conjugated diene polymer before hydrogenation. From the viewpoint of reducing the safety of the catalyst during the hydrogenation reaction, the aluminum content of the hydrogenated conjugated diene polymer of this embodiment is preferably 2 ppm or less, more preferably 1 ppm or less, and even more preferably contains no aluminum. Furthermore, by using lithium or magnesium instead of aluminum, the function of aluminum as a co-catalyst can be complemented. By adjusting the titanium content and aluminum content in the hydrogenation catalyst, the titanium content and aluminum content of the hydrogenated conjugated diene polymer can be controlled within the above-mentioned ranges.

[0036] (Nitrogen atom content) From the viewpoint of improving the fuel economy performance of the rubber composition, the hydrogenated conjugated diene polymer of this embodiment has a nitrogen atom content of preferably 20 ppm or more, more preferably 50 ppm or more, even more preferably 80 ppm or more, and even more preferably 120 ppm or more, while from the viewpoint of processability of the rubber composition, the nitrogen atom content is preferably 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less. The nitrogen atom content can be controlled by modifying the reaction initiation terminal, main chain, or reaction termination terminal of the polymer with a nitrogen-containing compound, and particularly by using a nitrogen-containing modifying agent.

[0037] (nitrogen atom content / silicon atom content) From the viewpoint of a balance between fuel economy performance and handling stability, the hydrogenated conjugated diene polymer of this embodiment preferably has a ratio (nitrogen atom content of the hydrogenated conjugated diene polymer) / (silicon atom content of the hydrogenated conjugated diene polymer) of 0.75 or more, more preferably 1.0 or more, and even more preferably 1.5 or more.

[0038] (coupling polymer) The hydrogenated conjugated diene polymer of the present embodiment is preferably a coupling polymer obtained by subjecting active terminals of a conjugated diene polymer obtained through a polymerization step and, if necessary, a branching step using a branching agent, to a coupling reaction using a bifunctional or higher functional reactive compound (hereinafter also referred to as a "coupling agent"). In the coupling step in which a coupling reaction is carried out using a coupling agent, one active end of the polymer is subjected to a coupling reaction with a predetermined coupling agent to obtain a coupled polymer.

[0039] <Coupling agent> The coupling agent that can be used in the coupling step may be any reactive compound having any structure, as long as it is a bifunctional or higher functional compound. Furthermore, a compound that has a nitrogen atom-containing group and can modify the reaction initiation terminal, main chain, or reaction termination terminal of a polymer is called a modifying agent. Regarding the coupling agents mentioned above, a coupling agent containing a nitrogen atom is both a coupling agent and a modifier.

[0040] The hydrogenated conjugated diene polymer of the present embodiment may be a hydrogenated conjugated diene polymer obtained by subjecting active terminals of a polymer obtained through a polymerization step and, if necessary, a branching step to a coupling reaction using a coupling agent or a modifier, and then subjecting the polymer to a hydrogenation step.

[0041] Examples of coupling agents include, but are not limited to, halogenated silane compounds such as silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethyltrichlorosilicon, monoethyltrichlorosilicon, monobutyltrichlorosilicon, monohexyltrichlorosilicon, monomethyltribromosilicon, and bistrichlorosilylethane; and halogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane. Further, examples include, but are not limited to, alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and alkyltriphenoxysilane.

[0042] In the coupling step, it is preferable to carry out a coupling reaction with a coupling agent having a nitrogen atom at one of the active terminals during polymerization of the conjugated diene polymer. When a polymer coupled with a coupling agent having a nitrogen atom is compounded into a rubber composition containing a filler, the polymer exhibits good dispersibility of fillers such as silica and carbon black, and the rubber composition containing the filler exhibits good processability. Furthermore, when the rubber composition is vulcanized, the rubber composition exhibits good abrasion resistance and breaking strength.

[0043] As the coupling agent containing a nitrogen atom, from the viewpoints of polymerization productivity and a high modification rate, for example, an isocyanate compound, an isothiocyanate compound, an isocyanuric acid derivative, a nitrogen group-containing carbonyl compound, a nitrogen group-containing vinyl compound, a nitrogen group-containing epoxy compound, a nitrogen group-containing alkoxysilane compound, and the like are preferred. Furthermore, when it is desired to improve the processability of the rubber composition, the number of branches of the polymer after the coupling reaction is preferably high, preferably 3 or more branches, and more preferably 4 or more branches.On the other hand, when it is desired to improve the tensile properties of the rubber composition, the number of branches is preferably 8 or less branches, preferably 6 or less branches, and more preferably 4 or less branches.

[0044] As the coupling agent containing a nitrogen atom, from the viewpoint of reactivity, a nitrogen group-containing alkoxysilane compound and a nitrogen group-containing polyfunctional modifier are preferred.

[0045] Examples of the nitrogen group-containing alkoxysilane compound include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacycloheptane, 2,2-dimethoxy-1-(3- 2-Methoxy,2-methyl-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-ethoxy,2-ethyl-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-Methoxy,2-methyl-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-Methoxy,2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, Tris(3-trimethoxysilylpropyl)amine, Tris(3-methyldimethoxysilylpropyl)amine, Tris(3-triethoxysilylpropyl)amine, Tris(3-methyldiethoxysilylpropyl)amine, Tris(trimethoxysilylmethyl)amine, Tris(2-trimethoxysilylethyl)amine, Tris(4-trimethoxysilylbutyl)amine, Tetrakis[3-(2,2-dimethoxy-1-azacyclopentane], [N-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N-methyl-N'-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N'-(3-(trimethoxysilyl)propyl)-1,3-propanediamine].

[0046] Examples of nitrogen-group-containing polyfunctional modifiers include, but are not limited to, compounds having one or more functional groups selected from an epoxy group, a carbonyl group, a carboxylic acid ester group, a carboxylic acid amide group, an acid anhydride group, a phosphate ester group, a phosphite ester group, an epithio group, a thiocarbonyl group, a thiocarboxylic acid ester group, a dithiocarboxylic acid ester group, a thiocarboxylic acid amide group, an imino group, an ethyleneimino group, a halogen group, an alkoxysilyl group, an isocyanate group, a thioisocyanate group, a conjugated diene group, and an arylvinyl group, and which have at least one nitrogen atom in the compound.

[0047] In calculating the number of moles of functional groups, an alkoxy group per epoxy group, carbonyl group, epithio group, thiocarbonyl group, imino group, ethyleneimino group, halogen group, conjugated diene group, arylvinyl group, or alkoxysilyl group should be counted as monofunctional; a carboxylic acid ester group, a carboxylic acid amide group, an acid anhydride group, a thiocarboxylic acid ester group, a dithiocarboxylic acid ester group, a thiocarboxylic acid amide group, an isocyanate group, or a thioisocyanate group should be counted as bifunctional; and a phosphate ester group or a phosphite ester group should be counted as trifunctional. The polyfunctional modifier that can be preferably used for modifying the hydrogenated conjugated diene-based polymer of the present embodiment is a polyfunctional modifier in which the sum of the numbers of the above-mentioned functional groups in one molecule is 2 or more, and more preferably a polyfunctional modifier in which the sum of the numbers of the functional groups in one molecule is 3 or more.

[0048] Furthermore, a terminal-modifying agent may be used as a modifying agent for modifying the hydrogenated conjugated diene polymer of the present embodiment. Examples of the terminal-modifying agent include, but are not limited to, 1,3-diethyl-2-imidazolinone, 1,3-dimethyl-2-imidazolinone, 1,3-dipropyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 1-methyl-3-propyl-2-imidazolinone, 1-methyl-3-butyl-2-imidazolinone, and 1,3-dihydro-1,3-dimethyl-2H-imidazol-2-one.

[0049] (denaturation rate) In this specification, unless otherwise specified, the "modification ratio" represents the mass ratio of the polymer having a nitrogen atom to the total amount of the hydrogenated conjugated diene polymer. For example, when a nitrogen atom-containing modifying agent is reacted with the terminal end of a polymer, the mass ratio of the polymer having a nitrogen atom-containing functional group due to the nitrogen atom-containing modifying agent to the total amount of the polymer is expressed as the modification rate. On the other hand, when a polymer is branched using a branching agent containing a nitrogen atom, the resulting copolymer also has a nitrogen atom-containing functional group, and therefore this branched polymer is also counted when calculating the modification rate. That is, in this specification, the total mass ratio of a coupling polymer formed by a modifying agent having a nitrogen atom-containing functional group and / or a branched polymer formed by a branching agent having a nitrogen atom-containing functional group is referred to as the "modification rate."

[0050] From the viewpoint of a balance between fuel economy performance and wet grip performance, the hydrogenated conjugated diene polymer of this embodiment preferably has a modification rate measured by a column adsorption GPC method (hereinafter also simply referred to as "modification rate") of 40% or more and 99% or less relative to the total amount of the hydrogenated conjugated diene copolymer. The modification rate is more preferably 60% or more, even more preferably 80% or more, and particularly preferably 90% or more. The upper limit of the modification rate is not particularly limited, but is, for example, 99% or less. The degree of modification can be measured, for example, by chromatography, which can separate functional group-containing modified components from unmodified components. Examples of methods using this type of chromatography include a method in which a gel permeation chromatography column filled with a polar substance such as silica that adsorbs specific functional groups is used, and the non-adsorbed components are quantified using an internal standard for comparison (column adsorption GPC method). More specifically, the modification rate can be determined by measuring the amount of adsorption onto the silica column from the difference between a chromatogram obtained by measuring a sample solution containing a sample and a low-molecular-weight internal standard polystyrene on a polystyrene gel column and a chromatogram obtained by measuring the sample solution on a silica column. More specifically, the modification rate can be measured by the method described in the Examples. In the hydrogenated conjugated diene polymer of this embodiment, the modification rate can be controlled to 40% or more and 99% or less by adjusting the amount of modifier added and the reaction method, for example. For example, the above-mentioned modification rate can be achieved by combining a method of polymerization using an organolithium compound having at least one nitrogen atom in the molecule as a polymerization initiator, which will be described later, a method of copolymerizing a monomer having at least one nitrogen atom in the molecule, and a method of using a modifying agent having a structural formula as will be described later, and controlling the polymerization conditions.

[0051] [Method for producing conjugated diene polymer] The hydrogenated conjugated diene-based polymer of the present embodiment is preferably obtained by carrying out a polymerization step using a predetermined polymerization initiator, followed by a modification step or a coupling reaction step preferably using the above-mentioned modifier or coupling agent, and then carrying out a hydrogenation step. More preferably, a branching step may be carried out using a branching agent before the coupling reaction step. A preferred method for producing the hydrogenated conjugated diene polymer of this embodiment preferably includes a step of polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer before modification; a modification step of reacting the conjugated diene polymer before modification obtained in the above step with an alkoxysilane compound to produce a modified conjugated diene polymer; and a step (hydrogenation step) of reacting the modified conjugated diene polymer with hydrogen to obtain a hydrogenated conjugated diene polymer. Furthermore, before the hydrogenation step, a reaction step of reacting the modified conjugated diene polymer with a macromonomer containing a repeating unit derived from an N-functional group-containing compound may be carried out.

[0052] Furthermore, before the hydrogenation step, a step of reacting the modified conjugated diene polymer with an alkyllithium compound or a reaction product of an alkyllithium compound and an N-functional group-containing compound may be included.

[0053] (Polymerization process) In the polymerization step, a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, is polymerized to obtain a conjugated diene polymer before modification. The polymerization initiator used in the polymerization step includes an organic monolithium compound. The organomonolithium compound is not limited to the following, but examples thereof include low molecular weight compounds and solubilized oligomeric organomonolithium compounds. Furthermore, examples of the organic monolithium compound include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond in terms of the bonding mode between the organic group and the lithium.

[0054] The amount of the organic monolithium compound used as the polymerization initiator is preferably determined depending on the structure of the target conjugated diene polymer and the molecular weight of the conjugated diene polymer. The amount of a monomer such as a conjugated diene compound used relative to the amount of a polymerization initiator used is related to the degree of polymerization, that is, tends to be related to the number average molecular weight and / or weight average molecular weight. Therefore, in order to increase the molecular weight, it is advisable to adjust the amount of polymerization initiator used in a direction to decrease it, and in order to decrease the molecular weight, it is advisable to adjust the amount of polymerization initiator used in a direction to increase it.

[0055] As the organic monolithium compound, an alkyllithium compound having a substituted amino group or a dialkylaminolithium is preferred from the viewpoint that it can be used as one method for introducing nitrogen atoms into a conjugated diene polymer. In this case, a conjugated diene polymer having a nitrogen atom consisting of an amino group at the polymerization initiation terminal is obtained.

[0056] The substituted amino group is an amino group that does not have an active hydrogen or has a structure in which the active hydrogen is protected. Examples of alkyllithium compounds having an amino group that does not have an active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium. Examples of alkyllithium compounds having an amino group with a structure in which an active hydrogen is protected include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0057] Examples of dialkylaminolithiums include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium-di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0058] These organomonolithium compounds having a substituted amino group can also be used as solubilized oligomeric organomonolithium compounds by reacting them with a small amount of a polymerizable monomer, such as 1,3-butadiene, isoprene, or styrene.

[0059] The organic monolithium compound is preferably an alkyllithium compound from the viewpoints of industrial availability and ease of control of the polymerization reaction, in which case a copolymer having an alkyl group at the polymerization initiation terminal can be obtained. Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium. As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferred from the viewpoints of industrial availability and ease of control of the polymerization reaction. These organomonolithium compounds may be used alone or in combination of two or more, or may be used in combination with other organometallic compounds. Examples of the other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds. Alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds, as well as alkaline earth metal alkoxides, sulfonates, carbonates, and amides. Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0060] In the polymerization step, the polymerization reaction mode is not limited to the following, but examples thereof include a batchwise (also called a "batch type") and a continuous polymerization reaction mode. In the continuous system, one or more connected reactors can be used. The continuous reactor may be, for example, a tank-type or tubular reactor equipped with a stirrer. In the continuous system, preferably, the monomers, the inert solvent, and the polymerization initiator are continuously fed to the reactor, a polymer solution containing a conjugated diene polymer is obtained in the reactor, and the conjugated diene polymer solution is continuously discharged. The batch reactor may be, for example, a tank-type reactor equipped with a stirrer. In the batch reactor, preferably, a monomer, an inert solvent, and a polymerization initiator are fed, and if necessary, a monomer is added continuously or intermittently during the polymerization step to obtain a polymer solution containing a conjugated diene polymer in the reactor, and the conjugated diene polymer solution is discharged after the polymerization is completed.

[0061] In the method for producing a hydrogenated conjugated diene polymer of this embodiment, in order to obtain a conjugated diene polymer having active ends at a high rate, a continuous method is preferred, which allows the polymer to be continuously discharged and subjected to the next reaction in a short period of time.

[0062] The polymerization step is preferably carried out in an inert solvent. Examples of inert solvents include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and hydrocarbons consisting of mixtures thereof.

[0063] By treating the impurities, that is, allenes and acetylenes, with an organometallic compound before subjecting the polymer to the polymerization reaction, a conjugated diene-based polymer having a high concentration of active ends tends to be obtained, and a modified conjugated diene-based polymer with a high modification rate tends to be obtained, which is preferable.

[0064] In the polymerization step, a polar compound (polar substance) may be added. This allows the aromatic vinyl compound to be randomly copolymerized with the conjugated diene compound, and the polar compound (polar substance) tends to be usable as a vinylating agent for controlling the microstructure of the conjugated diene portion. It also tends to be effective in accelerating the polymerization reaction. Examples of polar compounds include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, and sodium amylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

[0065] The amount of the polar compound used is not particularly limited and can be selected depending on the purpose, etc., but is preferably 0.01 moles or more and 10 moles or less per mole of the polymerization initiator. Such polar compounds (vinylating agents) can be used in an appropriate amount depending on the desired amount of 1,2-vinyl bonds as modifiers for the microstructure of the conjugated diene moiety in the conjugated diene polymer. Many polar compounds also have an effective randomizing effect in the copolymerization of a conjugated diene compound and an aromatic vinyl compound, and tend to be used as modifiers for adjusting the distribution of aromatic vinyl monomer units and the amount of styrene blocks. As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140211, a copolymerization reaction may be initiated with the entire amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene may be intermittently added during the copolymerization reaction.

[0066] The polymerization temperature in the polymerization step is preferably a temperature at which living anionic polymerization proceeds, and from the viewpoint of productivity, is more preferably 0°C or higher, and even more preferably 120°C or lower. By keeping the temperature in this range, it tends to be possible to ensure a sufficient amount of modifying agent reacting with the active terminals after the polymerization is completed. Even more preferably, it is 50°C or higher and 100°C or lower.

[0067] (Coupling step, modification step) The active terminals of the conjugated diene polymer obtained through the above-mentioned polymerization step and, if necessary, a branching step using a predetermined branching agent are subjected to a coupling reaction or a modification reaction using the above-mentioned coupling agent or modifying agent, preferably an alkoxysilane compound. In the coupling step or the modification step, a plurality of coupling agents or modifying agents may be used.

[0068] (Reaction step) The method for producing the hydrogenated conjugated diene polymer of this embodiment may include, as a reaction step after the coupling step and the modification step, a step of adding to the polymerization solution a macromonomer containing a repeating unit derived from an N-functional group-containing compound, an alkyllithium compound or a reaction product of an alkyllithium compound and an N-functional group-containing compound, or an oligomer using, as a polymerization initiator, a reaction product of an alkyllithium compound and an N-functional group-containing compound. This makes it possible to produce a hydrogenated conjugated diene polymer having graft chains derived from a macromonomer containing a repeating unit derived from an N-functional group-containing compound.

[0069] By adding a macromonomer containing repeating units derived from an N-functional group-containing compound, an alkyllithium compound or a reaction product of an alkyllithium compound with an N-functional group-containing compound, or an oligomer using a reaction product of an alkyllithium compound with an N-functional group-containing compound as a polymerization initiator, the residues of reactive groups derived from the coupling agent or modifier can be reacted with the macromonomer, alkyllithium compound, or their reaction product. Adding more than one mole of coupling agent or modifier, calculated as reactive groups, per mole of polymerization initiator results in an excess of reactive groups, which will remain in the system. The residues of reactive groups derived from the coupling agent or modifier bonded to the polymer can bond over time through condensation reactions, resulting in the formation of polymeric components and an increase in Mooney viscosity. However, adding a macromonomer containing repeating units derived from the N-functional group-containing compound, an alkyllithium compound or a reaction product of an alkyllithium compound with an N-functional group-containing compound, or an oligomer using a reaction product of an alkyllithium compound with an N-functional group-containing compound as a polymerization initiator can suppress the condensation reaction and reduce the increase in Mooney viscosity.

[0070] Examples of the N-functional group-containing compound used in the macromonomer containing a repeating unit derived from an N-functional group-containing compound include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, and compounds represented by the following structural formulae A to D. The macromonomer is preferably a macromonomer obtained by copolymerizing one or more of the following N-functional group-containing compounds using an alkyllithium compound as a polymerization initiator. The macromonomer may be one obtained by polymerizing one or more of the following N-functional group-containing compounds with a conjugated diene compound, or a conjugated diene compound with an aromatic vinyl compound.

[0071] [ka]

[0072] In the structural formula A, R1-R2 are CH2-CH2 or CH=CH. R3-R4 are CH2-CH2, CH=N, or N=N.

[0073] [ka]

[0074] In the above structural formula B, R 11 and R 12 are each independently an alkyl group having 1 to 20 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heteroalkyl group having 1 to 20 carbon atoms; a heteroalkenyl group having 2 to 20 carbon atoms; a heteroalkynyl group having 2 to 20 carbon atoms; a cycloalkyl group having 5 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; a heterocyclic group having 3 to 20 carbon atoms; or a functional group represented by the following structural formula C. R 13 is an alkyl group having 1 to 20 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heteroalkyl group having 1 to 20 carbon atoms; a heteroalkenyl group having 2 to 20 carbon atoms; a heteroalkynyl group having 2 to 20 carbon atoms; a cycloalkyl group having 5 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; a heterocyclic group having 3 to 20 carbon atoms; a vinyl group; or a functional group represented by the following structural formula C. R 11 , R 12 , and R 13 At least one of the groups is a functional group represented by the following structural formula C, and is bonded at the "*" portion in structural formula C described below.

[0075] [ka]

[0076] In the above structural formula C, R 21is a single bond, or an alkylene group having 1 to 20 carbon atoms which may or may not be substituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms which may or may not be substituted with a substituent; or an arylene group having 6 to 20 carbon atoms which may or may not be substituted with a substituent. The substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R 22 and R 23 are each independently an alkyl group having 1 to 20 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heteroalkyl group having 1 to 20 carbon atoms; a heteroalkenyl group having 2 to 20 carbon atoms; a heteroalkynyl group having 2 to 20 carbon atoms; a cycloalkyl group having 5 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; a heterocyclic group having 3 to 20 carbon atoms; or a mono-, di-, or tri-substituted alkylsilyl group substituted with an alkyl group having 1 to 10 carbon atoms.

[0077] [ka]

[0078] In the above structural formula D, R 31 is a single bond, or an alkylene group having 1 to 20 carbon atoms which may or may not be substituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms which may or may not be substituted with a substituent; or an arylene group having 6 to 20 carbon atoms which may or may not be substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R 32 and R 33are each independently an alkyl group having 1 to 20 carbon atoms; an alkenyl group having 2 to 20 carbon atoms; an alkynyl group having 2 to 20 carbon atoms; a heteroalkyl group having 1 to 20 carbon atoms; a heteroalkenyl group having 2 to 20 carbon atoms; a heteroalkynyl group having 2 to 20 carbon atoms; a cycloalkyl group having 5 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms; a heterocyclic group having 3 to 20 carbon atoms; or a mono-, di-, or tri-substituted alkylsilyl group substituted with an alkyl group having 1 to 10 carbon atoms.

[0079] (Deactivator addition process, neutralizer addition process) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, after the modification step and the coupling step, a deactivator, a neutralizer, and the like may be added to the polymer solution as needed. The quenching agent is not limited to the following, but examples thereof include water; alcohols such as methanol, ethanol, and isopropanol; and the like. Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched carboxylic acid mixture having 9 to 11 carbon atoms, mainly 10 carbon atoms); aqueous solutions of inorganic acids; and carbon dioxide gas.

[0080] (Hydrogenation process) In the method for producing the hydrogenated conjugated diene polymer of the present embodiment, the hydrogenation reaction may be carried out by carrying out the polymerization step, and, if necessary, the branching step, the modification step, and the coupling step, and, if necessary, the reaction step and the quencher addition step.

[0081] (Addition of rubber stabilizer) In the method for producing the hydrogenated conjugated diene polymer of this embodiment, it is preferable to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing. The rubber stabilizer is not limited to the following and known stabilizers can be used, but preferred are antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0082] (Desolvation process) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, a known method can be used to obtain the resulting hydrogenated conjugated diene polymer from the polymer solution. The method is not particularly limited, and examples thereof include a method in which the solvent is separated by steam stripping or the like, the polymer is filtered, and then the polymer is dehydrated and dried to obtain the polymer, a method in which the polymer is concentrated in a flashing tank and then devolatilized using a vent extruder or the like, and a method in which the polymer is directly devolatilized using a drum dryer or the like.

[0083] [Rubber composition] A rubber composition using the hydrogenated conjugated diene polymer of this embodiment (hereinafter sometimes referred to as the rubber composition of this embodiment) preferably contains at least 10 mass % of the hydrogenated conjugated diene polymer of this embodiment described above as a rubber component, and preferably contains 10 parts by mass or more and 150 parts by mass or less of a filler per 100 parts by mass of the rubber component, and the filler preferably includes at least one of a silica-based inorganic filler, carbon black, and calcium carbonate.

[0084] (filler) The filler preferably contains at least one of silica-based inorganic fillers, carbon black, and calcium carbonate, and these may be used alone or in combination of two or more.Fillers other than those mentioned above may also be contained.

[0085] The silica-based inorganic filler is not particularly limited and any known filler can be used, but solid particles containing SiO2 or Si3Al as a structural unit are preferred, and solid particles containing SiO2 or Si3Al as a main component of the structural unit are more preferred. Here, the main component refers to a component contained in the silica-based inorganic filler in an amount of 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. Examples of silica-based inorganic fillers include, but are not limited to, inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Other examples include silica-based inorganic fillers with hydrophobic surfaces and mixtures of silica-based inorganic fillers with non-silica-based inorganic fillers. Among these, silica and glass fiber are preferred, and silica is more preferred, from the viewpoints of strength and abrasion resistance. Examples of silica include dry silica, wet silica, and synthetic silicate silica.

[0086] Examples of carbon black include, but are not limited to, carbon blacks of various classes such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon blacks with a nitrogen adsorption specific surface area of ​​50 m 2 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred. In the hydrogenated conjugated diene polymer composition of this embodiment, the content of carbon black is preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 120 parts by mass or less, and even more preferably 15 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the hydrogenated conjugated diene polymer of this embodiment. The carbon black content within the above range is preferable from the viewpoints of strength at break, compression set, and hardness.

[0087] The calcium carbonate is not particularly limited, but examples thereof include calcium carbonate having an average particle size of 0.04 μm to 8.0 μm and an oil absorption of 10 to 35 g per 100 g of calcium carbonate.

[0088] The filler may contain fillers other than those mentioned above, such as metal oxides and metal hydrides. Metal oxides are compounds with the chemical formula M x O y (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) as the main component of the structural unit. Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide. Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0089] The rubber composition of the present embodiment may contain a silane coupling agent. The silane coupling agent has the function of strengthening the interaction between the rubber component and the inorganic filler, and has groups that have affinity or bonding properties for both the rubber component and the silica-based inorganic filler. Preferably, the silane coupling agent is a compound that has a sulfur-bonding moiety and an alkoxysilyl group or silanol group moiety in one molecule. Examples of such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide. In the rubber composition of this embodiment, the content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1.0 to 15 parts by mass, relative to 100 parts by mass of the inorganic filler. When the content of the silane coupling agent is within the above range, the effect of the addition of the silane coupling agent tends to be more pronounced.

[0090] (rubber softener) The rubber composition of the present embodiment may contain a rubber softener as needed. The rubber softener is preferably added in order to improve the productivity of the hydrogenated conjugated diene polymer and the processability of a rubber composition containing a filler or the like. The rubber softener is not particularly limited, but examples thereof include extender oil, liquid rubber, and resin.

[0091] A preferred method for adding a rubber softener to a hydrogenated conjugated diene-based polymer or a rubber composition is, for example, to add the rubber softener to a polymer solution, mix them, and remove the solvent from the resulting polymer solution containing the rubber softener.

[0092] Preferred extender oils include, for example, aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils having a polycyclic aromatic (PCA) content of 3% by mass or less according to the IP346 method are preferred from the viewpoints of environmental safety, oil bleeding prevention, and wet grip properties. Examples of aromatic substitute oils include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0093] Preferred liquid rubbers include, but are not limited to, liquid polybutadiene, liquid styrene-butadiene rubber, and the like. The effects of adding liquid rubber include improving the processability of a rubber composition containing a hydrogenated conjugated diene polymer and a filler, etc., and shifting the glass transition temperature of the rubber composition to a lower temperature, thereby improving the abrasion resistance, low hysteresis loss, and low-temperature properties of the vulcanized product.

[0094] Preferred resins include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenolic resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, aromatic petroleum resins, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols. These resins may be used alone or in combination. When hydrogenating, all unsaturated groups may be hydrogenated, or some may remain. The effects of adding a resin include an improvement in the processability of a rubber composition containing a hydrogenated conjugated diene polymer and a filler, etc., and a tendency to improve the breaking strength of a vulcanized product. In addition, the glass transition temperature of the rubber composition can be shifted to a higher temperature, which tends to improve wet skid resistance.

[0095] The amount of extender oil, liquid rubber, resin, or the like added as a rubber softener is preferably 1 part by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, and even more preferably 10 parts by mass or more and 37.5 parts by mass or less, relative to 100 parts by mass of the hydrogenated conjugated diene-based polymer of the present embodiment. When the rubber softener is added within the above range, the processability of a rubber composition containing the hydrogenated conjugated diene polymer and a filler or the like is improved, and the breaking strength and abrasion resistance of a vulcanized product tend to be improved.

[0096] (Method of manufacturing rubber composition) Specific mixing methods for obtaining the rubber composition of the present embodiment include, but are not limited to, a melt-kneading method using a general mixer such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder, and a method in which the components are dissolved and mixed and then the solvent is removed by heating. Among these, the melt kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferred from the viewpoint of productivity and good kneading properties. In addition, it is possible to use either a method in which the rubber component, other fillers, silane coupling agent, and additives are kneaded at once, or a method in which they are mixed in several batches.

[0097] (Vulcanized composition) The rubber composition of the present embodiment may be a vulcanized composition that has been subjected to vulcanization treatment with a vulcanizing agent. Examples of vulcanizing agents include, but are not limited to, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. The sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric polysulfur compounds, and the like. In the rubber composition of this embodiment, the content of the vulcanizing agent is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is preferably 120°C to 200°C, and more preferably 140°C to 180°C. In vulcanization, a vulcanization accelerator may be used as needed. The vulcanization accelerator may be a conventionally known material, including, but not limited to, sulfenamide, guanidine, thiuram, aldehyde-amine, aldehyde-ammonia, thiazole, thiourea, and dithiocarbamate vulcanization accelerators. The vulcanization aid may be, but not limited to, zinc oxide, stearic acid, and triallyl isocyanurate. The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component. Examples of organic peroxides include 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexene-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,2'-bis(tert-butylperoxy)-p-isopropylbenzene, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, and p-mene. Examples of suitable peroxides include tallow peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butyl peroxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy)perbenzoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, and tert-butylperoxyisopropyl carbonate.

[0098] (Other additives) The rubber composition of the present embodiment may contain various additives other than those described above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants, within the scope of the present embodiment without impairing the object of the present embodiment. As other softeners, known softeners can be used. Other fillers include, but are not limited to, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used for the heat stabilizer, antistatic agent, weather stabilizer, antioxidant, colorant, and lubricant.

[0099] (Uses of rubber compositions) The rubber composition of this embodiment can be used as a tire, packing or gasket, sealant, vibration-proof rubber, vibration-isolating rubber, conveyor belt, shoe outsole or midsole, automotive weatherstrip, glass run, trunk lid, railroad vehicle component, aircraft component, waterproof sheet, engine mount, air spring, rubber gloves, medical and sanitary products, industrial and various application hoses, battery cases, adhesives, electric wire coating, window frame rubber, rubber roll, rubber roller for office equipment and spinning, keypad, keyboard cover, underwater goggles, swimming cap, container bag, marine-related parts, indoor flooring, artificial muscle material, various industrial product materials, etc. In these applications, various molded articles can be obtained by molding the rubber composition of this embodiment. [Example]

[0100] Hereinafter, the present embodiment will be described in more detail with reference to specific polymerization examples, examples, and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples. Various physical properties in the examples and comparative examples were measured by the methods shown below.

[0101] [Physical property measurement method] (Number of peaks, weight average molecular weight, molecular weight distribution) The chromatogram was measured using a GPC measuring device with three columns connected together, each packed with polystyrene gel, and the weight-average molecular weight (Mw), number of peaks, and molecular weight distribution were determined based on a calibration curve using standard polystyrene. The specific measurement conditions are shown below. 20 μL of the following measurement solution was injected into the GPC measurement device and the measurement was carried out. <Measurement conditions> Device: Tosoh Corporation, product name "HLC-8320GPC" Eluent: 5mmol / L triethylamine in tetrahydrofuran (THF) Guard column: Tosoh Corporation's product name "TSKguardcolumn SuperH-H" Separation column: Tosoh Corporation product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" connected in this order. Oven temperature: 40°C Flow rate: 0.6mL / min Detector: RI detector (Tosoh Corporation, product name "HLC8020") Measurement solution: 10 mg of sample dissolved in 20 mL of THF Regarding the molecular weight distribution, the molecular weight distribution (PDI) of the hydrogenated conjugated diene polymer immediately after polymerization and desolvation was i ) and the molecular weight distribution (PDI) of the hydrogenated conjugated diene polymer after leaving it at 25°C for 90 days after polymerization and desolvation. f ) was measured, and the molecular weight distribution change rate ΔPDI was calculated using the above formula (2).

[0102] (denaturation rate) The modification rate was measured by the column adsorption GPC method, utilizing the property of the modified polymer to be adsorbed onto a column, as follows. The amount of adsorption onto the silica-based column was measured by subtracting the chromatogram of a sample solution containing the sample and low-molecular-weight internal standard polystyrene measured using a column packed with polystyrene-based gel from the chromatogram measured using a column packed with silica-based gel, and the modification rate was calculated. <GPC measurement conditions using a polystyrene column> The GPC measurement conditions using a polystyrene column are as follows: 20 μL of the measurement solution below was injected into the GPC measurement device and the measurement was carried out. Device: Tosoh Corporation, product name "HLC-8320GPC" Eluent: THF containing 5mmol / L triethylamine Guard column: Tosoh Corporation's product name "TSKguardcolumn SuperH-H" Column: Tosoh Corporation product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" connected in this order Oven temperature: 40°C Flow rate: 0.6mL / min Detector: RI detector (Tosoh HLC8020) Measurement solution: 10 mg of sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution. <GPC measurement conditions using a silica column> The conditions for GPC measurement using a silica column are as follows: 50 μL of the measurement solution below was injected into the GPC measurement device and measurement was carried out. Device: Tosoh Corporation, product name "HLC-8320GPC" Eluent:THF Guard column: GL Sciences product name "DIOL 4.6 x 12.5 mm 5 micron" Separation column: Agilent Technologies' Zorbax PSM-1000S, PSM-300S, and PSM-60S columns connected in this order Oven temperature: 40℃, Flow rate: 0.5mL / min Detector: RI detector (Tosoh HLC8020) <Calculation method of denaturation rate>: The total peak area of ​​the chromatogram using the polystyrene column was set to 100, the peak area of ​​the sample was set to P1, the peak area of ​​the standard polystyrene was set to P2, and the total peak area of ​​the chromatogram using the silica column was set to 100, the peak area of ​​the sample was set to P3, and the peak area of ​​the standard polystyrene was set to P4. The modification rate (%) was calculated using the following formula. Denaturation rate (%) = [1-(P2 x P3) / (P1 x P4)] x 100 (However, P1+P2=P3+P4=100)

[0103] (Mooney viscosity) The Mooney viscosity and Mooney stress relaxation (relaxation rate) of each polymer were measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with JIS K6300 (ISO289-1) and ISO289-4. The measurement temperature was 100°C. Here, the sample was preheated for 1 minute, then the rotor was rotated at 2 rpm, and the torque was measured after 4 minutes to determine the Mooney viscosity (ML (1+4) ) was decided. The Mooney viscosity (ML) of the hydrogenated conjugated diene polymer immediately after polymerization and desolvation i ), and the Mooney viscosity (ML f ) was measured, and the rate of change in Mooney viscosity (ΔML) was calculated using the above formula (1).

[0104] (Styrene content, butylene content, hydrogenation rate of hydrogenated conjugated diene polymer, and 1,2-vinyl bond amount of conjugated diene polymer before hydrogenation) The conjugated diene polymer before hydrogenation was used as a sample. 1 The content of 1,2-vinyl bonds was calculated from the integrated value of the polymer before hydrogenation by H-NMR measurement. Next, the hydrogenated conjugated diene polymer was used as a sample. 1 The styrene content, butylene bond amount, and hydrogenation rate of the hydrogenated conjugated diene polymer were measured by H-NMR. 1 The conditions for H-NMR measurement are as follows: (Measurement conditions) Measuring equipment: JNM-LA400 (JEOL) Solvent: deuterated chloroform Measurement sample: Samples taken before and after hydrogenation of polymer Sample concentration: 50mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0105] (styrene block content) A chain consisting of eight or more styrene structural units was defined as a styrene block, and the styrene block content was calculated as follows. 400MHz measured using deuterated chloroform as a solvent 1 From the 1 H-NMR spectrum, the integral ratio of each chemical shift range of the following (X) was determined, and the content of the styrene block contained in each hydrogenated conjugated diene polymer was calculated. (X) Aromatic vinyl compounds with 8 or more chains: 6.00≦S<6.68

[0106] (silicon atom content) The silicon atom content was measured by elemental analysis using a hydrogenated conjugated diene polymer as a sample, using an inductively coupled plasma (ICP, Inductive Coupled Plasma, manufactured by Shimadzu Corporation, device name: ICPS-8100), to measure the silicon atom content (unit: ppm) in the polymer.

[0107] (Nitrogen atom content) The nitrogen atom content was calculated using a hydrogenated conjugated diene polymer as a sample using a TN-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd., in accordance with the method described in 4. Chemiluminescence method in JIS K2609:1998, Determination of Nitrogen Content in Crude Oil and Petroleum Products.

[0108] [Characteristics evaluation method] (Bale forming ability) 30 kg of crumbs of hydrogenated conjugated diene polymer were placed in a bale forming mold (length 70 cm, width 35 cm) and compressed under a compression pressure of 140 to 250 kg / cm. 2 The pressure-molded body was molded under the conditions of a compression time of 15 to 60 seconds and a compression temperature of 60°C, and the surface condition of the obtained pressure-molded body was evaluated according to the following criteria. Good: The rubber does not fall apart when touched with the hand, or the rubber breaks down slightly into powder when touched with the hand. ×: When you touch the surface, the rubber tends to break apart and the veil tends to crack. For practical purposes, bale formability must be 0.

[0109] (Adhesion to PTFE sheet) The adhesion of the polymer to the PTFE sheet was evaluated as an index of productivity. Twenty samples were prepared by molding the polymers obtained in the Examples and Comparative Examples described below into 0.5 cm cubes. These samples were placed on a 1 mm thick PTFE sheet on an iron metal plate and heated at 80°C in air for 20 minutes. The iron plate with the samples placed on it was then rotated 180°, inverted, and held for 10 seconds. The number of samples that adhered to the PTFE and did not fall off was used for evaluation. If 11 or more out of 20 particles remained on the sheet, there was a concern that they would adhere to the manufacturing equipment, resulting in a very poor productivity, and therefore the sheet was marked as x. Furthermore, if 4 to 10 out of 20 pieces remained on the sheet, it was rated as △, since although adhesion to the manufacturing equipment was observed during production, it was highly likely that production was still possible. Furthermore, if there were 3 or less samples remaining on the sheet out of 20, it was deemed acceptable because it was expected that there would be little adhesion to the manufacturing equipment during production and that production volume would be good. For practical purposes, adhesion to PTFE sheets must be △ or 〇.

[0110] (Productivity) If both the bale formability and adhesion to the PTFE sheet were rated as either 0 or △, it was judged that the product was actually producible and rated as 0. If either or both items were rated as x, it was judged that the productivity was very poor and rated as x.

[0111] [Manufacturing example] (Preparation of hydrogenation catalyst) In the examples and comparative examples described later, the hydrogenation catalyst used in producing the hydrogenated conjugated diene polymer was prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 L of dried and purified cyclohexane was placed in the vessel. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While thoroughly stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the reaction was carried out at room temperature for about 3 days. This produced a hydrogenation catalyst (T).

[0112] (Preparation of additives) In the examples and comparative examples described later, piperidinolithium (compound 6) used in producing hydrogenated conjugated diene polymers was prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 0.1 L of dried and purified cyclohexane was placed in the vessel. Next, 1 mol of tetrahydrofuran and 10 mmol of piperidine were added. The mixture was stirred while controlling the temperature at 25° C. Next, 10 mmol of normal butyllithium was added, and the mixture was stirred for 10 minutes to obtain piperidinolithium (Compound 6).

[0113] (Preparation of Oligomer A) In the examples and comparative examples described later, oligomer A used in producing hydrogenated conjugated diene polymers was prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 0.2 L of dried and purified tetrahydrofuran was placed in the vessel. Next, 30 mmol of N,N-dimethyl-1-(4-vinylphenyl)methanamine was added. The mixture was stirred while controlling the temperature at 10°C. Next, 10 mmol of normal butyllithium was added, and after stirring for 1 hour, oligomer A, a macromonomer containing repeating units derived from an N-functional group-containing compound, was obtained. Gas chromatography analysis showed that the polymerization conversion rate of the N,N-dimethyl-1-(4-vinylphenyl)methanamine monomer was 99% or more, confirming that the reaction was complete.

[0114] (Preparation of Oligomer B) In the examples and comparative examples described later, oligomer B used in producing hydrogenated conjugated diene polymers was prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 0.2 L of dried and purified tetrahydrofuran was placed in the vessel. Next, 30 mmol of 2-vinylpyridine was added. The mixture was stirred while controlling the temperature at 10°C. Next, 10 mmol of normal butyllithium was added, and after stirring for 1 hour, oligomer B, a macromonomer containing repeating units derived from an N-functional group-containing compound, was obtained. Gas chromatography analysis showed that the polymerization conversion rate of 2-vinylpyridine monomer was 99% or more, confirming that the reaction was complete.

[0115] [Production of conjugated diene polymer and hydrogenated conjugated diene polymer] (Comparative Example 1): Polymer 1 Two tank-type pressure vessels with an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator-equipped tank-type reactor equipped with an agitator and a jacket for temperature control were connected together as polymerization reactors. Pre-dehydrated 1,3-butadiene, styrene, and n-hexane were mixed at 26.4 g / min, 2.3 g / min, and 175.2 g / min. A static mixer was installed in the pipe supplying this mixed solution to the reactor inlet, and n-butyllithium (treated n-butyllithium) for inactivating remaining impurities was added at 0.104 mmol / min. The mixture was then continuously fed to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane (BOP) was added at 0.048 mmol / min as a polar substance, and n-butyllithium (polymerization initiator n-butyllithium) was added at 0.319 mmol / min as a polymerization initiator. The mixture was then fed to the bottom of the first reactor, where it was being vigorously mixed with a stirrer, to initiate polymerization. The reactor temperature was maintained at 67 °C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously fed to the bottom of the second reactor, where the reaction was continued at 70°C, and further fed to a static mixer from the top of the second reactor. Next, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (compound 1) was continuously added as a coupling agent at a rate of 0.13 mmol / min to the polymer solution flowing out of the reactor outlet, and the mixture was mixed using a static mixer to carry out a coupling reaction. At this time, it took 4.8 minutes for the coupling agent to be added to the polymer solution flowing out of the reactor outlet, and the temperature was 68°C, and the difference between the temperature during the polymerization process and the temperature before the addition of the coupling agent was 2°C. Further, n-butyllithium (compound 5) was added at a rate of 0.27 mmol / min, and mixed using a static mixer to react with the remaining reactive groups of the coupling agent. Next, to the obtained solution of the conjugated diene polymer, 0.4 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 0.1 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants per 100 g of polymer, and the solvent was then removed by steam stripping to obtain Polymer 1. The analytical results of Polymer 1 are shown in Table 4.

[0116] (Comparative Example 2): Polymer 2 The same treatment as in Comparative Example 1 described above was carried out up to the step of reacting the coupling agent, and then the obtained conjugated diene polymer solution was transferred to another reactor without adding Compound 5, and the hydrogenation catalyst (T) prepared above was added in an amount of 50 ppm (Ti standard) per 100 parts by mass of the conjugated diene polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a solution of a hydrogenated conjugated diene polymer. The hydrogenation rate of the structural units derived from butadiene in the obtained hydrogenated conjugated diene polymer was 75%. Thereafter, an antioxidant was added in the same manner as in Comparative Example 1, and the solvent was removed to obtain Polymer 2. The analytical results of Polymer 2 are shown in Table 4.

[0117] (Comparative Example 3): Polymer 3 Similar to the above-mentioned Comparative Example 1, after the coupling reaction, Compound 5 was added and reacted. Thereafter, a hydrogenation reaction was carried out similar to Comparative Example 2. Thereafter, similar to Comparative Example 1, an antioxidant was added, and the solvent was removed to obtain Polymer 3. The analytical results of Polymer 3 are shown in Table 4.

[0118] (Examples 1 to 11, Comparative Example 4): Polymers 4 to 8, 10 to 15, Polymer 9 Polymerization was carried out under the conditions shown in Tables 1 and 2, and in some cases, a hydrogenation reaction was carried out. In Example 4, piperidine was added at the same time as 2,2-bis(2-oxolanyl)propane (compound 1), and compound 6 was reacted with compound 5 after the coupling reaction. In Example 8, compound 1 was added as a coupling agent, and after reacting for 5 minutes, compound 2 was added and reacted for another 10 minutes. Similarly, in Example 9, compound 3 was added as a coupling agent and reacted for 5 minutes, and then compound 2 was added and reacted for an additional 10 minutes. In Example 10, compound 4 was added as a coupling agent, and after reacting for 5 minutes, compound 2 was added and reacted for an additional 10 minutes. The timing of addition of the oligomer in Examples 6 and 7 was the same as that of Compound 5 in Comparative Example 1, and the oligomer was added instead of Compound 5. In the hydrogenation reactions in Examples 1 to 11, the hydrogenation rate was controlled to the values ​​shown in Tables 4 and 5 by adjusting the amount of hydrogen added and the reaction time while keeping the amount of hydrogenation catalyst added constant. For each polymer, an antioxidant was added in the same manner as in Comparative Example 1, and the solvent was removed to obtain polymers 4 to 15. The analytical results of polymers 4 to 8 are shown in Table 4. The analytical results of polymers 9 to 15 are shown in Table 5.

[0119] (Comparative Example 5): Polymer 16 As shown in Table 3, a 40 L internal volume, temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor. 2,370 g of 1,3-butadiene, 630 g of styrene, 21,000 g of cyclohexane, and 224.8 mmol of tetrahydrofuran (THF) and 12 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, all of which had been previously removed, were placed in the reactor, and the internal temperature of the reactor was maintained at 33°C. As a polymerization initiator, 15.0 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction started, the temperature inside the reactor rose due to heat generated by the polymerization, and the final temperature inside the reactor was 80°C. To this polymer solution, 15.0 mmol of compound 2 was added as a coupling agent, and the reaction was carried out for 10 minutes. Thereafter, 15.0 mmol of oligomer A was added, and the reaction was carried out for 20 minutes. Thereafter, an antioxidant was added in the same manner as in Comparative Example 1, and the solvent was removed to obtain Polymer 16. The analytical results of polymer 16 are shown in Table 6.

[0120] (Comparative Example 6): Polymer 17 Polymerization was carried out in the same manner as in Comparative Example 5 under the conditions shown in Table 3, and then the hydrogenation catalyst (T) prepared above was added in an amount of 50 ppm (Ti) per 100 parts by mass of the conjugated diene polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and an average temperature of 85° C. to obtain a solution of a hydrogenated conjugated diene polymer. The hydrogenation rate of the structural units derived from butadiene in the obtained hydrogenated conjugated diene polymer was 80%. Thereafter, an antioxidant was added in the same manner as in Comparative Example 1, and the solvent was removed to obtain Polymer 17. The analytical results of polymer 17 are shown in Table 6.

[0121] The types of activators in Tables 1 to 3 are as follows: Compound 1: 2,2-Dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane Compound 2: N-methyl-3-(trimethoxysilyl)-N-(3-(trimethoxysilyl)propyl)propan-1-amine Compound 3: Silicon tetrachloride Compound 4: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane Compound 5: n-butyllithium Compound 6: Piperidinolithium Oligomer A: Oligomer of N,N-dimethyl-1-(4-vinylphenyl)methanamine Oligomer B: Oligomer of 2-vinylpyridine

[0122] [Table 1]

[0123] [Table 2]

[0124] [Table 3]

[0125] [Table 4]

[0126] [Table 5]

[0127] [Table 6]

[0128] [Production of Rubber Composition] (Raw rubber component) ·Polymer 1~17:80 parts by mass High-cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.): 20 parts by mass

[0129] (Combination conditions) The raw rubber component: 100 parts by mass Silica 1 (trade name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m2 / g): 50.0 parts by mass Silica 2 (Rhodia's Zeosil Premium 200MP, nitrogen adsorption specific surface area 220 m / g): 25.0 parts by mass Carbon black (product name "Seat KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass SRAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation): 25.0 parts by mass ·Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by weight Antioxidant (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7 parts by mass Vulcanization accelerator 2 (diphenyl guanidine): 2.0 parts by mass ·Total: 222.4 parts by mass

[0130] (Kneading method) The above materials were kneaded by the following method to obtain a rubber composition. In the first stage of mixing, the raw rubber components, fillers (Silica 1, Silica 2, carbon black), silane coupling agent, SRAE oil, zinc oxide, and stearic acid were mixed using an internal mixer (capacity: 0.3 L) equipped with a temperature control device at a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. During this mixing, the temperature of the internal mixer was controlled, and the discharge temperature was 155 to 160°C, to obtain each rubber composition (compound). Next, in the second stage of mixing, the mixture obtained above was cooled to room temperature, and then an antioxidant was added and mixed again to improve the dispersion of the silica. In this case, the discharge temperature of the mixture was also adjusted to 155 to 160°C by controlling the temperature of the mixer. After cooling, the mixture was mixed in the third stage using an open roll set at 70°C, adding sulfur and vulcanization accelerators 1 and 2 to form a sheet. The mixture was then molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber composition before and after vulcanization were evaluated. Specifically, the evaluation was carried out using the following methods. The results are shown in Tables 7 to 9.

[0131] (Evaluation of rubber composition properties) The sheet moldability of the rubber composition, the tensile strength, tensile elongation, fuel saving performance due to viscoelasticity, wet grip performance, and abrasion resistance of the rubber composition were measured.

[0132] <Sheet moldability of rubber composition> In the above-mentioned kneading method, in the third stage of kneading, sulfur and vulcanization accelerators 1 and 2 were added and kneaded with an open roll set at 70℃ to prepare a sheet. The number of voids formed in the sheet was used as an index of processability during compound preparation. The greater the number of pores in the sheet, the more likely it is that breaks will occur during sheet forming, meaning poorer workability. 10cm when the sheet thickness of the rubber composition is 1cm or less 2 The average number of pores per 1 cm was counted. 2 The above are defined as voids. The average number of holes in the molded sheet is 2 or more per 10cm 2 ×, more than 0 and less than 2 / 10cm 2 The case where there was no void in the rubber composition sheet was evaluated as △, and the case where there was no void in the rubber composition sheet was evaluated as ◯. For practical purposes, it was necessary to give a rating of either ◯ or △, and in the case of ×, it was determined that there was a problem with processability.

[0133] <Tensile strength, tensile elongation> The tensile strength and tensile elongation of the vulcanized rubber composition were measured in accordance with the tensile test method of JIS K6251. The measuring device used was AUTOGRAPH AGS-X manufactured by Shimadzu Corporation. For Comparative Examples 2 and 3 and Examples 1 to 5, the tensile strength and tensile elongation were evaluated as ◯ if they were improved by 10% or more compared to Comparative Example 1, △ if they were between -5% and 10%, and × if they were worse than -5%. For Comparative Examples 5, 6, and Examples 6 to 11, an improvement of 10% or more compared to Comparative Example 4 was evaluated as ◯, an improvement of -5% or more but less than 10% as △, and a deterioration of more than -5% as ×.

[0134] <Fuel efficiency and wet grip performance> Viscoelastic parameters were measured in torsion mode using a viscoelastic testing machine "ARES" manufactured by Rheometrics Scientific. Tan δ measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of fuel economy. The smaller the index, the better the fuel economy. In addition, tan δ measured at 0° C., a frequency of 10 Hz, and a strain of 1% is used as an index of wet grip performance, with a larger value indicating better wet skid performance. For both fuel economy performance and wet grip performance, for Comparative Examples 2 and 3 and Examples 1 to 5, if the improvement was 10% or more compared to Comparative Example 1, it was marked as ◯, if it was -5% or more but less than 10%, it was marked as △, and if it was worse than -5%, it was marked as ×. For Comparative Examples 5, 6, and Examples 6 to 11, an improvement of 10% or more compared to Comparative Example 4 was evaluated as ◯, an improvement of -5% or more but less than 10% as △, and a deterioration of more than -5% as ×.

[0135] <Performance balance of tensile strength, tensile elongation, fuel economy, and wet grip performance> The balance of tensile strength, tensile elongation, fuel economy, and wet grip performance was evaluated on a three-point scale: A, B, and C. B is standard, A indicates an excellent balance, and C indicates a poor balance of performance. Comparative Examples 2 and 3 and Examples 1 to 5 were evaluated for tensile strength, tensile elongation, fuel economy performance, and wet grip performance compared to Comparative Example 1, and Examples 1 to 5 had no "x" rating and were given a "good" rating for one or more performance items, indicating a performance balance better than existing technology, and were therefore given an A for the performance balance. On the other hand, Comparative Examples 2 and 3 had one or more "x" ratings and were inferior to Comparative Example 1 in terms of physical property balance, and were therefore given a C. Similarly, Comparative Examples 5 and 6 and Examples 6 to 11 were evaluated for tensile strength, tensile elongation, fuel economy performance, and wet grip performance compared to Comparative Example 4, and Examples 6 to 11 had no "x" and were rated "o" in one or more performance categories, indicating a performance balance better than existing technology, and the performance balance was rated A. On the other hand, Comparative Examples 5 and 6 had one or more "x" categories and were inferior in physical property balance to Comparative Example 4, so they were rated C.

[0136] [Table 7]

[0137] [Table 8]

[0138] [Table 9]

[0139] It was confirmed that the hydrogenated conjugated diene polymers obtained in Examples 1 to 11 have no problems with productivity, maintain processability, and are excellent in tensile strength, tensile elongation, fuel economy performance, and wet grip performance, compared to the conjugated diene polymers obtained in Comparative Examples 1 to 6. [Industrial Applicability]

[0140] The hydrogenated conjugated diene polymer of the present invention has industrial applicability as tire treads and sidewalls, as well as packings, gaskets, sealing materials, vibration-proof rubber, vibration-isolating rubber, vibration-damping materials, conveyor belts, shoe outsoles and midsoles, automobile weather strips, glass runs, trunk lids, railway vehicle components, aircraft components, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary products, hoses for industrial and various uses, battery cases, adhesives, wire coatings, window frame rubber, rubber rollers for office automation equipment and spinning, etc., keypads, keyboard covers, underwater goggles, swimming caps, container bags, marine-related parts, indoor flooring materials, artificial muscle materials, and materials for various industrial products.

Claims

1. The Mooney viscosity change rate (ΔML) represented by the following formula (1) is 1% or more and 40% or less, The peak shape obtained from the molecular weight distribution curve in GPC measurement is unimodal, The hydrogenation rate is 10% or more and 100% or less. Hydrogenated conjugated diene polymer. ΔML=[(ML f -ML i ) / ML i ]×100 ・・・(1) (In the above formula (1), ΔML is the rate of change of Mooney viscosity, and ML f is the Mooney viscosity at 100°C after leaving the hydrogenated conjugated diene polymer at 25°C for 90 days, and ML i is the initial Mooney viscosity of the hydrogenated conjugated diene polymer at 100°C.

2. The hydrogenated conjugated diene polymer has a nitrogen atom content of 20 ppm or more. The hydrogenated conjugated diene polymer according to claim 1.

3. the hydrogenated conjugated diene polymer has a silicon atom content of 20 ppm or more; The hydrogenated conjugated diene polymer according to claim 1.

4. (nitrogen atom content of the hydrogenated conjugated diene polymer) / (silicon atom content of the hydrogenated conjugated diene polymer) is 0.75 or more; The hydrogenated conjugated diene polymer according to claim 1.

5. The weight average molecular weight of the hydrogenated conjugated diene polymer is 100,000 or more and 2,000,000 or less. The hydrogenated conjugated diene polymer according to claim 1.

6. In the formula (1), the initial Mooney viscosity (ML i ) is 30 or more and 200 or less, The hydrogenated conjugated diene polymer according to claim 1.

7. the molecular weight distribution of the hydrogenated conjugated diene polymer as measured by GPC is less than 1.7; The hydrogenated conjugated diene polymer according to claim 1.

8. the butylene content of the hydrogenated conjugated diene polymer is 10 mol % or more and 60 mol % or less; The hydrogenated conjugated diene polymer according to claim 1.

9. The molecular weight distribution change rate (ΔPDI) represented by the following formula (2) is 2% or more and 30% or less, The hydrogenated conjugated diene polymer according to claim 1. ΔPDI(%)=[|(PDI f -PDI i )| / PDI i ]×100 ・・・(2) (In formula (2), ΔPDI is the rate of change in molecular weight distribution, and PDI i is the molecular weight distribution of the hydrogenated conjugated diene polymer immediately after polymerization, and PDI f is the molecular weight distribution of the hydrogenated conjugated diene polymer after standing at 25°C for 90 days.

10. having a graft chain derived from a macromonomer containing a repeating unit derived from an N-functional group-containing compound; The hydrogenated conjugated diene polymer according to claim 1.

11. A method for producing the hydrogenated conjugated diene polymer according to claim 1, a polymerization step of polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer before modification; a modification step of reacting the unmodified conjugated diene polymer with an alkoxysilane compound to produce a modified conjugated diene polymer; a reaction step of reacting the modified conjugated diene polymer with a macromonomer containing a repeating unit derived from an N-functional group-containing compound; a hydrogenation step of reacting with hydrogen to obtain a hydrogenated conjugated diene-based polymer after the reaction step, A method for producing a hydrogenated conjugated diene polymer.

12. A method for producing the hydrogenated conjugated diene polymer according to claim 1, a polymerization step of polymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer before modification; a modification step of reacting the unmodified conjugated diene polymer with an alkoxysilane compound to produce a modified conjugated diene polymer; a reaction step of reacting the modified conjugated diene-based polymer with an alkyllithium compound or a reaction product of an alkyllithium compound and an N-functional group-containing compound; a hydrogenation step of reacting with hydrogen to obtain a hydrogenated conjugated diene-based polymer after the reaction step, A method for producing a hydrogenated conjugated diene polymer.

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