Hydrogenated conjugated diene-based polymer

Abstract

To provide a hydrogenated conjugated diene-based polymer capable of achieving superior ozone resistance while exhibiting a good balance of processability, fuel economy, and tensile performance when formulated into a rubber composition, for example.SOLUTION: A hydrogenated conjugated diene-based polymer satisfies the following conditions (1) to (4): [Condition 1] a molecular weight distribution is 1.0 or more and 5.0 or less; [Condition 2] a weight-average molecular weight is 100,000 or more and 3,000,000 or less; [Condition 3] a hydrogenation ratio is 20% or more and 99% or less; and [Condition 4] a Mooney stress relaxation area represented by the following formula (1) is 500 MU / s or more.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, with the demand for reducing the environmental impact of automobiles, there has been a demand for conjugated diene polymers as rubber materials for tires that have an excellent balance of processability, low rolling resistance, and tensile properties, as well as excellent ozone resistance.

[0003] Conventionally, in order to improve the balance between processability and low rolling resistance performance, it has become common to use modified conjugated diene polymers. However, in order to improve tensile properties using modified conjugated diene polymers, it is necessary to increase the molecular weight. However, increasing the molecular weight tends to increase the solution viscosity and melt viscosity, reduce productivity due to powder generation during drying, and deteriorate processability during composition preparation. To solve these problems, the balance between increasing the molecular weight and processability during compound preparation has been improved by controlling the branching degree of the polymer.

[0004] For example, Patent Document 1 proposes improving the balance between processability, low rolling resistance, and tensile properties by combining modified conjugated diene polymers with different degrees of branching. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2022-521399 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the increasing demand for reducing the environmental impact of automobiles in recent years, the conjugated diene polymer described in Patent Document 1 still has an insufficient balance between processability, fuel-saving performance, and tensile properties, and there are also problems in that improvements in tire durability performance, such as ozone resistance, are also required.

[0007] In view of the above-mentioned problems of the conventional art, the present invention aims to provide a hydrogenated conjugated diene polymer that, when made into a rubber composition, can achieve excellent ozone resistance while exhibiting a good balance between processability, fuel-saving performance, and tensile properties. [Means for solving the problem]

[0008] As a result of extensive research to solve the problems of the prior art described above, the present inventors have found that a hydrogenated conjugated diene-based polymer satisfying specific conditions can, for example, when made into a rubber composition, significantly improve the balance of processability, fuel-saving performance, tensile properties, and ozone resistance, and have thus completed the present invention.

[0009] That is, the present invention is as follows.

[0010] [1] A hydrogenated conjugated diene polymer that satisfies the following conditions (1) to (4): <Condition (1)> The molecular weight distribution is 1.0 or more and 5.0 or less. <Condition (2)> The weight-average molecular weight is 100,000 or more and 3,000,000 or less. <Condition (3)> The hydrogenation rate must be between 20% and 99%. <Condition (4)> The Mooney stress relaxation area, expressed by the following formula (1), is 500 MU / s or more.

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[0011] The hydrogenated conjugated diene polymer of the present invention can provide a rubber composition that is excellent in fuel-saving performance, tensile properties, and ozone resistance without impairing processability during compound preparation. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the following embodiment is an example for explaining the present invention, and the present invention is not limited to these. In other words, the present invention can be implemented by making any modifications within the scope of the gist of the present invention. Note that in this specification, when an expression using "~" is used with a numerical value or physical property value before and after it, it is used to include the values ​​before and after it.

[0013] In this specification, the term "monomer" 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.

[0014] [Hydrogenated conjugated diene polymer] The hydrogenated conjugated diene polymer of this embodiment satisfies the following conditions (1) to (4). <Condition (1)> The molecular weight distribution is 1.0 or more and 5.0 or less. <Condition (2)> The weight-average molecular weight is 100,000 or more and 3,000,000 or less. <Condition (3)> The hydrogenation rate must be between 20% and 99%. <Condition (4)> The Mooney stress relaxation area, expressed by the following formula (1), is 500 MU / s or more.

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[0015] By satisfying these conditions, the hydrogenated conjugated diene polymer of the present embodiment can achieve, for example, excellent ozone resistance while exhibiting a good balance of processability, fuel-saving performance, and tensile properties when made into a rubber composition.

[0016] The hydrogenated conjugated diene polymer of this embodiment can be obtained, for example, by hydrogenating a polymer containing a conjugated diene compound.

[0017] The conjugated diene compound is not particularly limited, but examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of effectively and reliably achieving the effects of the present embodiment. These conjugated diene compounds may be used alone or in combination of two or more.

[0018] The hydrogenated conjugated diene polymer of this embodiment may contain a monomer unit other than that derived from a conjugated diene compound, and preferably contains, for example, a unit derived from an aromatic vinyl compound.

[0019] The aromatic vinyl compound is not particularly limited, but examples thereof include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of effectively and reliably achieving the effects of the present embodiment. These aromatic vinyl compounds may be used alone or in combination of two or more.

[0020] 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").

[0021] (aromatic vinyl monomer unit content) From the viewpoint of tensile strength, the hydrogenated conjugated diene polymer of this embodiment preferably contains aromatic vinyl monomer units. In the hydrogenated conjugated diene polymer of this embodiment, the content of aromatic vinyl monomer units is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 4% by mass or more, and particularly preferably 6% by mass or more. On the other hand, from the viewpoint of fuel economy, the content of aromatic vinyl monomer units in the hydrogenated conjugated diene polymer of this embodiment is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0022] The content of the aromatic vinyl monomer unit can be controlled by the amount of the aromatic vinyl compound added during polymerization. 1 It can be measured by H-NMR.

[0023] (Aromatic vinyl monomer block content) In addition, in the hydrogenated conjugated diene polymer of the present embodiment, the content of the aromatic vinyl monomer block is preferably less than 10% by mass, more preferably 8% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2.0% by mass or less, from the viewpoint of processability.

[0024] 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.

[0025] The method for measuring 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 using a conjugated diene polymer before hydrogenation as a sample, decomposing the polymer by the Kolthoff method (the method described in I. M. Kolthoff, et al., J. Polym. Sci. 1, 429 (1946)), and analyzing the amount of polystyrene insoluble in methanol.

[0026] (hydrogenation rate) In the present embodiment, the hydrogenation rate of the hydrogenated conjugated diene polymer refers to the proportion (molar ratio) of double bonds in the structure derived from the conjugated diene monomer unit that have become saturated bonds through a hydrogenation reaction.

[0027] The hydrogenation rate of the hydrogenated conjugated diene polymer of this embodiment is 20% or more, preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, still more preferably 60% or more, and particularly preferably 70% or more, from the viewpoints of tensile properties and ozone resistance. On the other hand, from the viewpoints of ease of vulcanization, processability, and fuel economy, the hydrogenation rate is 99% or less, preferably 97% or less, more preferably 95% or less, even more preferably less than 90%, and particularly preferably less than 85%.

[0028] 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.

[0029] In this embodiment, the hydrogenation rate is the same as that described in the examples below. 1 It can be measured by H-NMR.

[0030] (hydrogenation reaction) The hydrogenated conjugated diene polymer of this embodiment can be obtained, for example, by hydrogenating (adding hydrogen) the conjugated diene moiety described below.

[0031] 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 monomer by anionic polymerization under various additives and conditions, copolymerize it with other monomers as needed, and then hydrogenate the resulting polymer.

[0032] The hydrogenation reaction may be carried out by either a batch process or a continuous process, or a combination thereof. The temperature of the hydrogenation reaction is not particularly limited, but is preferably 60 to 105°C, and more preferably 70 to 100°C.

[0033] (vinyl bond content, butylene bond content) In the hydrogenated conjugated diene polymer of this embodiment, the content of 1,2-vinyl bonds in the conjugated diene polymer before hydrogenation (hereinafter also referred to as "vinyl bond amount" or "1,2-vinyl bond amount") refers to the molar ratio of 1,2-vinyl bonds in the conjugated diene monomer unit content. In the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of tensile properties, the 1,2-vinyl bond amount is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 58 mol% or less. On the other hand, in the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of processability, the 1,2-vinyl bond amount is preferably 15 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more.

[0034] In the hydrogenated conjugated diene polymer of this embodiment, the butylene bond content is preferably a structure in which 1,2-vinyl bonds of the conjugated diene polymer are hydrogenated. The butylene bond content is expressed as a molar ratio in the conjugated diene monomer units in the hydrogenated conjugated diene polymer. In the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of processability, the butylene bond content is preferably 10 mol % or more, more preferably 15 mol % or more, even more preferably 20 mol % or more, and particularly preferably 25 mol % or more. On the other hand, in the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of tensile properties, the butylene bond content is preferably 65 mol % or less, more preferably 60 mol % or less, even more preferably 55 mol % or less, and particularly preferably 50 mol % or less.

[0035] The butylene bond content can be controlled by the polymerization temperature during polymerization and the amount of a polar compound added, which will be described later. 1 In addition, when a hydrogenated conjugated diene polymer is used as a sample, the vinyl bond content and butylene bond content can be measured. 1 The content of 1,2-vinyl bonds can be measured by H-NMR.

[0036] (Weight average molecular weight) The weight average molecular weight (Mw) of the hydrogenated conjugated diene polymer of this embodiment is 100,000 or more, preferably 150,000 or more, more preferably 200,000 or more, and particularly preferably 300,000 or more, from the viewpoint of fuel economy. On the other hand, the weight average molecular weight (Mw) of the hydrogenated conjugated diene polymer of this embodiment is 3,000,000 or less, preferably 2,000,000 or less, more preferably 1,500,000 or less, and particularly preferably 1,300,000 or less, from the viewpoint of processability and bale formability.

[0037] 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 conjugated diene polymer of the present embodiment can be measured by gel permeation chromatography (hereinafter also referred to as "GPC"). Specifically, it can be measured by the method described in the examples below.

[0038] (GPC peak number, molecular weight distribution) From the viewpoint of improving productivity and processability, the hydrogenated conjugated diene polymer of the present embodiment preferably has four or fewer peaks, more preferably three or fewer peaks, even more preferably two or fewer peaks, and particularly preferably a single peak, in a molecular weight distribution curve obtained by GPC measurement.

[0039] In this embodiment, the GPC peak 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, which is a point on the baseline or a maximum value sandwiched between minimum values.

[0040] From the viewpoint of fuel economy, the molecular weight distribution of the hydrogenated conjugated diene polymer of this embodiment is 5.0 or less, preferably 3.0 or less, more preferably 2.5 or less, even more preferably 2.1 or less, and particularly preferably 2.0 or less. From the viewpoint of processability, the molecular weight distribution of the hydrogenated conjugated diene polymer of this embodiment is 1.0 or more, preferably 1.1 or more, more preferably 1.2 or more, even more preferably 1.3 or more, and particularly preferably 1.5 or more.

[0041] The number of peaks and molecular weight distribution in the molecular weight distribution curve obtained by GPC measurement can be controlled by the polymerization method (batch polymerization or continuous polymerization), the temperature during polymerization, the amount of polar substance added during the polymerization reaction, and the type and amount of additives (such as coupling agents and modifiers).

[0042] For example, continuous polymerization tends to produce a broader molecular weight distribution than batch polymerization. Furthermore, the molecular weight distribution tends to be broader when the polymerization temperature is high or when a coupling agent or a modifier is added. To achieve a molecular weight distribution of less than 2.0 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.

[0043] (Mooney viscosity) The Mooney viscosity (ML) of the hydrogenated conjugated diene polymer of this embodiment at 100°C when an L-type rotor is used 1+4 ) (hereinafter also simply referred to as "Mooney viscosity") is preferably 20 or more, more preferably 30 or more, even more preferably 40 or more, and particularly preferably 50 or more, from the viewpoint of fuel economy and tensile properties. On the other hand, the Mooney viscosity of the hydrogenated conjugated diene polymer of the present embodiment is preferably 200 or less, more preferably 180 or less, even more preferably 160 or less, and particularly preferably 150 or less, from the viewpoint of processability.

[0044] The Mooney viscosity of the hydrogenated conjugated diene polymer of this embodiment can be measured by the method described in the examples below.

[0045] Mooney viscosity (ML) of hydrogenated conjugated diene polymers at 100°C using an L-type rotor 1+4 ) can be controlled by, for example, the molecular weight of the hydrogenated conjugated diene polymer, the hydrogenation rate, etc. Specifically, if the weight average molecular weight Mw is 200,000 or more and 1,000,000 or less, it can often be controlled within the above range.

[0046] Furthermore, since the Mooney viscosity tends to increase as the hydrogenation rate increases, when the hydrogenation rate is 70% or higher, it is preferable that the weight average molecular weight Mw be 100,000 or more and 700,000 or less, and when the hydrogenation rate is 50% or less, it is preferable that the weight average molecular weight Mw be 200,000 or more and 800,000 or less.

[0047] The hydrogenated conjugated diene polymer of the present embodiment may be a hydrogenated conjugated diene polymer obtained by reacting the active terminal of a polymer obtained through a polymerization step and, if necessary, a branching step with a modifier or a coupling agent, and then subjecting the polymer to a hydrogenation step.

[0048] (Mooney stress relaxation rate) The Mooney stress relaxation rate (MSR) of the hydrogenated conjugated diene polymer of this embodiment when an L-shaped rotor is used at 100°C (hereinafter also simply referred to as "Mooney stress relaxation rate") is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.5 or less, still more preferably 1.0 or less, and particularly preferably 0.7 or less from the viewpoint of processability. Also, from the viewpoint of tensile properties, it is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and particularly preferably 0.35 or more.

[0049] The Mooney stress relaxation rate of the hydrogenated conjugated diene polymer of this embodiment can be measured by the method described in the examples below.

[0050] The Mooney stress relaxation rate of a hydrogenated conjugated diene polymer at 100°C using an L-shaped rotor can be controlled, for example, by the molecular weight, degree of branching, etc. The Mooney stress relaxation rate can be adjusted to the above range, for example, by decreasing the molecular weight when the hydrogenated conjugated diene polymer has a high degree of branching, or by increasing the molecular weight when the hydrogenated conjugated diene polymer has a low degree of branching.

[0051] (Mooney stress relaxation area) The hydrogenated conjugated diene polymer of this embodiment has a Mooney stress relaxation area represented by the following formula (1) (hereinafter also simply referred to as "Mooney stress relaxation area") of 500 MU / s or more.

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[0052] The Mooney stress relaxation area of ​​the hydrogenated conjugated diene polymer of this embodiment can be measured by the method described in the examples below.

[0053] The Mooney stress relaxation area of ​​a hydrogenated conjugated diene polymer is a measure of stress relaxation of the hydrogenated conjugated diene polymer, and varies greatly depending on the composition of the elastic component and viscous component of the hydrogenated conjugated diene polymer. When the elastic component is high, stress relaxation is slow and the Mooney stress relaxation area tends to show a large value. Furthermore, slow relaxation tends to show a high elastic component, and fast relaxation tends to show a high viscous component.

[0054] The Mooney stress relaxation area of ​​a hydrogenated conjugated diene polymer is a value determined by a combination of various factors such as the degree of branching, molecular weight, molecular weight distribution, and modification rate of the hydrogenated conjugated diene polymer. Specifically, for example, when the degree of branching of the hydrogenated conjugated diene polymer is high or the molecular weight is high, the Mooney stress relaxation area tends to exhibit a large value, whereas when the degree of branching of the hydrogenated conjugated diene polymer is low or the molecular weight is low, the Mooney stress relaxation area tends to exhibit a small value.

[0055] From the viewpoints of processability and fuel economy, the hydrogenated conjugated diene polymer of this embodiment has a Mooney stress relaxation area (unit: MU / s) represented by the above formula (1) of preferably 500 or more, more preferably 750 or more, even more preferably 1000 or more, and particularly preferably 1500 or more. From the viewpoints of tensile properties and fuel economy, the hydrogenated conjugated diene polymer of this embodiment has a Mooney stress relaxation area represented by the above formula (1) of preferably 6000 or less, more preferably 5000 or less, even more preferably 4500 or less, and particularly preferably 4000 or less.

[0056] (Silicon content) From the viewpoint of fuel economy, the silicon atom content of the hydrogenated conjugated diene polymer of this embodiment (hereinafter also referred to as "silicon content") is preferably 50 ppm or more, more preferably 60 ppm or more, even more preferably 70 ppm or more, and particularly preferably 80 ppm or more. On the other hand, from the viewpoint of processability, the silicon content of the hydrogenated conjugated diene polymer of this embodiment is preferably 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less.

[0057] The silicon content can be controlled within the above range by adjusting the amount and type of coupling agent or modifier having a nitrogen atom-containing group, which will be described later.

[0058] (nitrogen content) The nitrogen atom content (hereinafter also referred to as "nitrogen content") of the hydrogenated conjugated diene polymer of this embodiment is preferably 20 ppm or more, more preferably 50 ppm or more, even more preferably 80 ppm or more, and particularly preferably 120 ppm or more from the viewpoint of improving fuel economy performance. On the other hand, the nitrogen content of the hydrogenated conjugated diene polymer of this embodiment is preferably 500 ppm or less, more preferably 400 ppm or less, and particularly preferably 300 ppm or less from the viewpoint of processability.

[0059] The nitrogen content is preferably determined by modifying the reaction initiation terminal, main chain, or reaction termination terminal of the polymer with a nitrogen-containing compound, and more preferably by using a nitrogen-containing modifying agent.

[0060] (Modified hydrogenated conjugated diene polymer) The hydrogenated conjugated diene polymer of the present embodiment is preferably a modified hydrogenated conjugated diene polymer obtained by subjecting the active terminals of a polymer obtained through a polymerization step and, if necessary, a branching step using a branching agent, to a modification reaction using a reactive compound (hereinafter also referred to as a "modifier").

[0061] In the modification step in which a modification reaction is carried out using a modifying agent, for example, one active end of the hydrogenated conjugated diene polymer is modified with a predetermined modifying agent to obtain a hydrogenated conjugated diene polymer.

[0062] The hydrogenated conjugated diene polymer of the present embodiment preferably contains a nitrogen atom. The hydrogenated conjugated diene polymer containing a nitrogen atom is not particularly limited, but can be obtained, for example, by carrying out a modification reaction using a modifier having a nitrogen atom-containing group described below.

[0063] When a hydrogenated conjugated diene polymer coupled with a modifier having a nitrogen atom-containing group is compounded with a filler or the like to form a hydrogenated conjugated diene polymer composition (rubber composition), the dispersibility of fillers such as silica and carbon black becomes good, and the rubber composition compounded with the filler or the like has good processability. In addition, when the rubber composition is vulcanized, the abrasion resistance and breaking strength tend to be good.

[0064] As the nitrogen atom-containing modifying agent, from the viewpoints of polymerization productivity and a high modification rate, 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.

[0065] Furthermore, from the viewpoint of reducing the viscosity of a crosslinked product (e.g., a crosslinked rubber composition) obtained using the hydrogenated conjugated diene polymer of this embodiment and improving the reduction in cracking of a compound sheet, it is preferable to use a modifier (hereinafter referred to as a "coupling agent") that can obtain a branched structure simultaneously with the modification reaction. The higher the number of branches of the coupling agent, the more preferable. The number of branches of the coupling agent is not particularly limited, but from the viewpoint of improving processability, 1.0 branches or more is preferable, 3.0 branches or more is more preferable, 3.5 branches or more is even more preferable, and 4.0 branches or more is particularly preferable. The upper limit of the number of branches is not particularly limited, but from the viewpoint of productivity, 30 branches or less is preferable.

[0066] The coupling agent containing a nitrogen atom is not particularly limited, but from the viewpoint of reactivity, preferred examples include nitrogen-group-containing alkoxysilane compounds and nitrogen-group-containing polyfunctional modifiers.

[0067] 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].

[0068] 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.

[0069] 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.

[0070] 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.

[0071] In the hydrogenated conjugated diene polymer of this embodiment, in addition to the coupling agents and modifiers described above, polyfunctional modifiers and coupling agents not containing a nitrogen atom, which will be described later, can also be used.

[0072] Examples of polyfunctional modifiers include, but are not limited to, polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether and glycerin triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenyl groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidyl Glycidylamino compounds such as aniline, diglycidyl orthotoluidine, tetraglycidyl meta-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; and compounds having epoxy groups and other functional groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltributoxysilane, epoxy-modified silicone, epoxidized soybean oil, and epoxidized linseed oil.

[0073] Furthermore, examples of coupling agents that do not contain nitrogen atoms include, but are not limited to, alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and alkyltriphenoxysilane; halogenated silane compounds such as silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethyltrichlorosilicon, monoethyltrichlorosilicon, monobutyltrichlorosilicon, monohexyltrichlorosilicon, monomethyltribromosilicon, and bistrichlorosilylethane; and alkoxyhalogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane.

[0074] Furthermore, examples of coupling agents that do not contain nitrogen atoms include, but are not limited to, halogenated tin compounds such as tin tetrachloride, tin tetrabromide, monomethyltrichlorotin, monoethyltrichlorotin, monobutyltrichlorotin, monophenyltrichlorotin, and bistrichlorostannylethane; polyhalogenated phosphorus compounds such as trichlorophosphine and tribromophosphine; phosphite compounds such as trisnonylphenylphosphite, trimethylphosphite, and triethylphosphite; and phosphate compounds such as trimethylphosphate and triethylphosphate.

[0075] Furthermore, a terminal modifying agent may be used as a modifying agent for modifying the conjugated diene polymer of this 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.

[0076] (denaturation rate) In this specification, unless otherwise specified, the "modification ratio" represents the mass ratio of the polymer having a nitrogen atom-containing functional group to the total amount of the hydrogenated conjugated diene polymer.

[0077] 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.

[0078] On the other hand, when a polymer is branched using a branching agent containing a nitrogen atom, the resulting polymer will also have a nitrogen atom-containing functional group, and therefore this branched polymer will also be counted when calculating the modification rate.

[0079] 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."

[0080] From the viewpoint of a balance among processability, abrasion resistance, breaking strength, and compression set, the hydrogenated conjugated diene polymer of the present embodiment preferably has a modification rate measured by a column adsorption GPC method (hereinafter also simply referred to as "modification rate") of 5% or more and 99% or less relative to the total amount of the hydrogenated conjugated diene polymer.

[0081] The modification rate is more preferably 20% or more, even more preferably 40% or more, even more preferably 60% or more, and particularly preferably 70% or more. The upper limit of the modification rate is not particularly limited, but is, for example, 99% or less.

[0082] The degree of modification can be measured, for example, by chromatography, which can separate functional group-containing modified components from unmodified components.

[0083] 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).

[0084] 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.

[0085] More specifically, in this embodiment, the modification rate can be measured by the method described in the examples.

[0086] In the hydrogenated conjugated diene polymer of this embodiment, the modification rate can be controlled, for example, by adjusting the amount of modifier added and the reaction method, and can thereby be controlled to 5% or more and 99% or less.

[0087] 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.

[0088] Furthermore, by modifying the polymerization initiation terminal with an amine, the ratio of modified polymer in the hydrogenated conjugated diene polymer can be adjusted. The method for modifying the polymerization initiation terminal of the conjugated diene portion of the hydrogenated conjugated diene polymer with an amine is not particularly limited, and known methods can be used. However, a preferred method is, for example, as described in JP 2018-16678 A, adding an organolithium compound as a polymerization initiator in the presence of an amine compound having active hydrogen to obtain a polymer chain having a nitrogen atom at the molecular end. Examples of amine compounds having active hydrogen include piperidine, hexamethylene, azacyclooctane, 1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, 1,2,3,6-tetrahydropyridine, and 3,5-dimethylpiperidine.

[0089] (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 relative to the hydrogenated conjugated diene polymer before hydrogenation.

[0090] In the hydrogenated conjugated diene polymer of this embodiment, the titanium content 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 tends to prevent yellow coloration of the hydrogenated conjugated diene polymer, and a titanium content of 1 ppm or more tends to eliminate the need for removal equipment, thereby reducing costs.

[0091] 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 hydrogenated conjugated diene polymer before hydrogenation.

[0092] In the hydrogenated conjugated diene polymer of this embodiment, the aluminum content is preferably 2 ppm or less, more preferably 1 ppm or less, from the viewpoint of reducing the safety of the catalyst during the hydrogenation reaction, and further preferably no aluminum is contained. Furthermore, by using lithium or magnesium instead of aluminum, the function of aluminum as a co-catalyst can be complemented.

[0093] Furthermore, from the viewpoints of suppressing an increase in Mooney viscosity (ML viscosity) and of the ease of handling and safety of the hydrogenation catalyst, the hydrogenation catalyst added during the production of the hydrogenated conjugated diene polymer preferably contains 0.05 mol or less of aluminum per mol of titanium, more preferably 0.04 mol or less of aluminum, even more preferably 0.03 mol or less of aluminum, and particularly preferably contains no aluminum.

[0094] For example, 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 to fall within the above-mentioned ranges.

[0095] (Method for producing hydrogenated conjugated diene polymer) The hydrogenated conjugated diene polymer of the present embodiment is preferably obtained by carrying out a polymerization step using a predetermined polymerization initiator, followed by a coupling reaction step preferably using the above-mentioned coupling agent, followed by a hydrogenation step. More preferably, a branching step using a branching agent may be carried out before the coupling reaction step.

[0096] (polymerization process) As the polymerization initiator used in the polymerization step, at least an organic monolithium compound can be used.

[0097] The organomonolithium compound is not limited to the following, but examples thereof include low molecular weight compounds and solubilized oligomeric organomonolithium compounds.

[0098] The organic monolithium compound is not particularly limited, but examples thereof 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.

[0099] The amount of the organic monolithium compound used as the polymerization initiator is preferably determined depending on the structure of the target polymer and the molecular weight of the polymer.

[0100] 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.

[0101] 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.

[0102] 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 hydrogenated conjugated diene polymer.

[0103] In this case, a polymer having a nitrogen atom consisting of an amino group at the polymerization initiation terminal can be obtained.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] The organic monolithium compound is preferably an alkyllithium compound from the viewpoints of industrial availability and ease of control of the polymerization reaction, which can produce a polymer having an alkyl group at the polymerization initiation terminal.

[0110] Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.

[0111] 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.

[0112] These organomonolithium compounds may be used alone or in combination of two or more, or may be used in combination with other organometallic compounds.

[0113] The other organometallic compounds are not particularly limited, but examples thereof include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0114] 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.

[0115] The organomagnesium compound is not particularly limited, but examples thereof include dibutylmagnesium and ethylbutylmagnesium. The other organometallic compounds are not particularly limited, but examples thereof include organoaluminum compounds.

[0116] 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.

[0117] In the continuous system, one or more connected reactors can be used. The continuous reactor is not particularly limited, but for example, a tank type or a tubular type equipped with a stirrer can be used. In the continuous system, preferably, the monomer, the inert solvent, and the polymerization initiator are continuously fed into the reactor, a polymer solution containing a polymer is obtained in the reactor, and the polymer solution is continuously discharged.

[0118] The batch reactor is not particularly limited, and for example, a tank-type reactor equipped with a stirrer is used. 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 polymerization, to obtain a polymer solution containing a polymer in the reactor, and the polymer solution is discharged after the polymerization is completed.

[0119] In the method for producing a hydrogenated conjugated diene polymer of this embodiment, in order to obtain a 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.

[0120] The polymerization step of the hydrogenated conjugated diene polymer is preferably carried out in an inert solvent. The solvent is not particularly limited, but examples thereof include 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.

[0121] By treating the impurities, that is, allenes and acetylenes, with an organometallic compound before subjecting the polymer to the polymerization reaction, a polymer having a high concentration of active ends tends to be obtained, and a modified hydrogenated conjugated diene-based polymer with a high modification rate tends to be obtained, which is preferable.

[0122] A polar compound (polar substance) may be added during the polymerization process. Aromatic vinyl compounds can be randomly copolymerized with conjugated diene compounds, and they tend to be useful as vinylating agents for controlling the microstructure of the conjugated diene moiety. They also tend to be effective in accelerating the polymerization reaction.

[0123] Examples of polar compounds that can be used 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.

[0124] These polar compounds may be used alone or in combination of two or more.

[0125] The amount of 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.

[0126] Such polar compounds (vinylating agents) can be used as modifiers for the microstructure of the conjugated diene moiety in the polymer in an appropriate amount depending on the desired amount of 1,2-vinyl bonds. 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 compounds and the amount of styrene blocks.

[0127] The method for randomizing the conjugated diene compound and the aromatic vinyl compound is not particularly limited. 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.

[0128] 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.

[0129] (Coupling process) The active terminals of the 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 with the above-mentioned coupling agent or a modifying agent having a nitrogen atom-containing group.

[0130] (Deactivator addition process, neutralizer addition process) In the method for producing a hydrogenated conjugated diene polymer of this embodiment, after the coupling step, a deactivator, a neutralizer, and the like may be added to the polymer solution, if necessary.

[0131] The quenching agent is not limited to the following, but examples thereof include water; alcohols such as methanol, ethanol, and isopropanol; and the like.

[0132] 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.

[0133] (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 above-mentioned polymerization step, and, if necessary, the branching step, the coupling step, and, if necessary, the deactivator addition step.

[0134] (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.

[0135] 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.

[0136] (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.

[0137] (Hydrogenated Conjugated Diene Polymer Composition) The hydrogenated conjugated diene polymer composition (rubber composition) of this embodiment may contain 0.1 to 200 parts by mass of a filler relative to 100 parts by mass of the hydrogenated conjugated diene polymer of this embodiment described above.

[0138] The content of the filler in the hydrogenated conjugated diene polymer composition of this embodiment is more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the hydrogenated conjugated diene polymer of this embodiment, from the viewpoint of exhibiting a reinforcing effect. On the other hand, from the viewpoint of sufficiently dispersing the filler and ensuring that the composition has practically sufficient processability and mechanical strength, the content is preferably 150 parts by mass or less, per 100 parts by mass of the hydrogenated conjugated diene polymer of this embodiment.

[0139] The filler is not particularly limited, but examples thereof include silica-based fillers, carbon black-based fillers, calcium carbonate, metal oxides, and metal hydrides. These may be used alone or in combination of two or more. Furthermore, fillers other than those mentioned above may also be contained.

[0140] As the filler, from the viewpoint of improving the breaking properties and wet grip properties when a composition is formed with the hydrogenated conjugated diene polymer of the present embodiment, a silica-based filler, a carbon black-based filler, or a combination of these is preferred.

[0141] The silica-based 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 filler in an amount of 50 mass% or more, preferably 70 mass% or more, and more preferably 80 mass% or more.

[0142] Specific silica-based 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 fillers with hydrophobic surfaces and mixtures of silica-based fillers with non-silica-based 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.

[0143] Examples of carbon black fillers 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.

[0144] 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.

[0145] 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.

[0146] Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0147] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0148] The hydrogenated conjugated diene polymer composition (rubber composition) of this 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. A compound having a sulfur-bonding moiety and an alkoxysilyl group or a silanol group moiety in one molecule is preferred. 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.

[0149] In the hydrogenated conjugated diene polymer 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 adding the silane coupling agent tends to be more pronounced. (rubber softener)

[0150] The hydrogenated conjugated diene polymer composition of the present embodiment may contain a rubber softener as needed. A rubber softener can be added as needed to further improve the productivity of the hydrogenated conjugated diene polymer and the processability of the composition when blended with a filler or the like.

[0151] The rubber softener is not particularly limited, but examples thereof include extender oil, liquid rubber, and resin.

[0152] The method for adding a rubber softener to a hydrogenated conjugated diene polymer or a hydrogenated conjugated diene polymer composition is not limited to the following methods. However, a preferred method involves adding a rubber softener to a hydrogenated conjugated diene polymer solution, mixing the solution, and removing the solvent from the resulting hydrogenated conjugated diene polymer solution containing the rubber softener.

[0153] Preferred extender oils include, for example, aromatic oils, naphthenic oils, and paraffinic oils. Among these, from the viewpoint of environmental safety, oil bleeding prevention, and wet grip properties, aromatic substitute oils having a polycyclic aromatic (PCA) content of 3% by mass or less according to the IP346 method are preferred. The aromatic substitute oil is not particularly limited, but examples thereof 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).

[0154] Preferred liquid rubbers include, but are not limited to, liquid polybutadiene, liquid styrene-butadiene rubber, and the like.

[0155] The effect of adding liquid rubber is that it improves the processability of a hydrogenated conjugated diene polymer composition prepared by blending the hydrogenated conjugated diene polymer with a filler or the like, and also shifts the glass transition temperature of the hydrogenated conjugated diene polymer composition (rubber composition) to a lower temperature, which tends to improve the abrasion resistance, low hysteresis loss, and low-temperature properties of the vulcanized product.

[0156] 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 hydrocarbon resins, aromatic petroleum resins, hydrogenated aromatic hydrocarbon resins, cycloaliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols. These resins may be used alone or in combination. When hydrogenating, all unsaturated groups may be hydrogenated, or some may remain.

[0157] The effects of adding a resin include improved processability when the hydrogenated conjugated diene polymer is blended with a filler or the like to form a conjugated diene polymer composition (rubber composition), and also tends to improve the breaking strength when the vulcanizate is formed. Furthermore, the glass transition temperature of the hydrogenated conjugated diene polymer composition (rubber composition) can be shifted to a higher temperature, which tends to improve wet skid resistance.

[0158] 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.

[0159] When the rubber softener is added within the above range, the processability of a hydrogenated conjugated diene polymer composition (rubber composition) containing the hydrogenated conjugated diene polymer and a filler or the like tends to be good, and the breaking strength and abrasion resistance of a vulcanized product tend to be good.

[0160] (Method for producing hydrogenated conjugated diene polymer composition (rubber composition)) Specific mixing methods for obtaining the hydrogenated conjugated diene polymer composition (rubber composition) of this 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.

[0161] Among these, melt-kneading methods using a roll, a Banbury mixer, a kneader, or an extruder are preferred from the viewpoints of productivity and good kneading ability. Also applicable are a method of kneading the rubber component, other fillers, silane coupling agent, and additives all at once, and a method of mixing them in several batches. (Vulcanized composition)

[0162] The hydrogenated conjugated diene polymer composition (rubber composition) of this embodiment may be a vulcanized composition that has been subjected to vulcanization treatment with a vulcanizing agent.

[0163] 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.

[0164] Examples of sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and polymeric polysulfide compounds. In the conjugated diene polymer composition (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. Conventionally known methods can be used for vulcanization, and the vulcanization temperature is preferably 120°C to 200°C, and more preferably 140°C to 180°C.

[0165] In vulcanization, a vulcanization accelerator may be used as needed.

[0166] The vulcanization accelerator may be a conventionally known material, and examples thereof include, but are not limited to, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, examples of the vulcanization aid include, but are not limited to, zinc oxide, stearic acid, and triallyl isocyanurate. The content of the vulcanization accelerator 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.

[0167] The organic peroxide is not particularly limited, but examples thereof 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, and tert-butyl peroxide. , p-menthane peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butyl peroxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy)perbenzoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, tert-butylperoxyisopropyl carbonate, and the like.

[0168] (Other additives) The hydrogenated conjugated diene polymer composition (rubber composition) of this embodiment may contain various additives other than those described above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants, within the scope of the present embodiment.

[0169] As other softeners, known softeners can be used.

[0170] Examples of other fillers include, but are not limited to, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used for the heat resistance stabilizer, antistatic agent, weather resistance stabilizer, antioxidant, colorant, and lubricant.

[0171] (Uses of hydrogenated conjugated diene polymer cross-linked product (cross-linked rubber composition))

[0172] The crosslinked hydrogenated conjugated diene polymer (crosslinked rubber composition) of this embodiment can be used as packing, gaskets, sealing materials, vibration-proof rubber, vibration-isolating rubber, conveyor belts, shoe outsoles and midsoles, automotive weatherstrips, glass runs, trunk lids, railroad 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 rolls, rubber rollers for office equipment and spinning, keypads, keyboard covers, underwater goggles, swimming caps, container bags, marine-related parts, indoor flooring materials, artificial muscle materials, materials for various industrial products, etc. In these applications, various molded articles can be obtained by molding the crosslinked hydrogenated conjugated diene polymer (crosslinked rubber composition) of this embodiment. [Example]

[0173] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.

[0174] Various physical properties in the examples and comparative examples were measured by the methods shown below.

[0175] [Styrene content of hydrogenated conjugated diene polymer, and 1,2-vinyl bond amount, butylene bond amount, and hydrogenation rate 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 (hereinafter also referred to as "vinyl bond amount") 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 aromatic vinyl content (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℃

[0176] [Weight-average molecular weight and molecular weight distribution of polymer] The chromatogram was measured using a GPC measurement device with three connected columns packed with polystyrene gel, and the weight average molecular weight (Mw) and molecular weight distribution of the polymer were determined based on a calibration curve using standard polystyrene. 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

[0177] [Mooney viscosity of polymer] The Mooney viscosity of the polymer was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with ISO 289. After preheating the sample at 100°C for 1 minute, the L-shaped rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to obtain the Mooney viscosity (ML(1+4)).

[0178] [Mooney stress relaxation rate of polymer] Using a polymer as a sample, a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used to measure the Mooney viscosity of the polymer using an L-shaped rotor in accordance with ISO 289. After that, the rotation of the rotor was immediately stopped, and the torque was recorded in Mooney units every 0.1 seconds for 1.6 to 5 seconds after the rotor was stopped. The torque versus time (seconds) was plotted logarithmically, and the slope of the straight line was determined. The absolute value of this slope was taken as the Mooney stress relaxation rate (MSR).

[0179] [Mooney stress relaxation area of ​​polymer] The Mooney stress relaxation area of ​​the polymer was measured using a Mooney viscometer (Ueshima Seisakusho Co., Ltd., trade name "VR1132") as follows. First, the polymer was left to stand at room temperature (23±5°C) for 30 minutes or more. After standing, 25±3 g of the polymer was taken and filled into the die cavity, and preheated at 100°C for 1 minute. The preheated polymer was rotated in an L-shaped rotor at 2 rpm, and the torque was measured after 4 minutes to determine the Mooney viscosity (ML (1+4) Thereafter, the Mooney stress relaxation area was calculated from the following formula (1) as the integral value of the Mooney stress relaxation curve for 120 seconds starting from 1 second after the rotor stopped.

number

[0180] [Polymer hydrogenation rate (hydrogenation rate)] 1 The integrated value of the unsaturated bond portion of the polymer before hydrogenation was obtained by H-NMR measurement. Next, a large amount of methanol was added to the reaction solution after the hydrogenation reaction to precipitate and recover the hydrogenated conjugated diene polymer. Next, the hydrogenated conjugated diene polymer was extracted with acetone and vacuum dried. This was 1 The hydrogenation rate of the hydrogenated conjugated diene polymer was measured using the sample for H-NMR measurement under the following conditions. (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℃

[0181] [Amount of block styrene in polymer] A chain consisting of eight or more styrene structural units is considered a styrene block, and the amount of styrene blocks in the polymer was calculated as follows: 1 The H-NMR spectrum was measured. From the spectrum, the integral ratio of each chemical shift range of the following (X) was determined, and the amount of styrene block contained in the hydrogenated conjugated diene polymer was calculated. Aromatic vinyl compounds with 8 or more chains: 6.00≦X<6.68

[0182] [Modification rate of polymer] The modification rate of a conjugated diene polymer was measured by column adsorption GPC as follows. The measurement was carried out by utilizing the property of a conjugated diene polymer modified with a nitrogen atom-containing functional group to be adsorbed onto a column. The amount of a sample solution containing the sample and a low-molecular-weight internal standard polystyrene adsorbed onto the silica column was measured from the difference between a chromatogram measured on a polystyrene column and a chromatogram measured on a silica column, and the modification rate was determined. Specifically, the method is as follows. <Preparation of sample solution>: 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution. THF containing 5 mmol / L triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the instrument for measurement. The guard column used was a Tosoh Corporation "TSKguardcolumn SuperH-H" (trade name), and columns were Tosoh Corporation "TSKgel SuperH5000," "TSKgel SuperH6000," and "TSKgel SuperH7000" (trade names). The column oven temperature was 40°C, and the THF flow rate was 0.6 mL / min. A chromatogram was obtained using an RI detector (Tosoh Corporation HLC8020). <GPC measurement conditions using a silica column>: A Tosoh HLC-8320GPC column was used, and 50 μL of the sample solution was injected into the column using THF as the eluent. Chromatograms were obtained using an RI detector at a column oven temperature of 40°C and a THF flow rate of 0.5 mL / min. Zorbax PSM-1000S, PSM-300S, and PSM-60S columns were used, with a DIOL 4.6 x 12.5 mm 5 micron guard column connected to the column. <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)

[0183] [Silicon content] The silicon content in the hydrogenated conjugated diene polymer was measured as follows: Using the hydrogenated conjugated diene polymer as a sample, the silicon content (unit: ppm) in the polymer was measured through elemental analysis using an inductively coupled plasma (ICP, Inductive Coupled Plasma, manufactured by Shimadzu Corporation, instrument name: ICPS-8100).

[0184] [Nitrogen content] The nitrogen content in the hydrogenated conjugated diene polymer was measured as follows: Using a hydrogenated conjugated diene polymer as a sample, a TN-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd. was used to calculate the nitrogen content (unit: ppm) in the polymer in accordance with the method described in 4. Chemiluminescence method in JIS K2609:1998, Determination method for nitrogen content in crude oil and petroleum products.

[0185] [Preparation of hydrogenation catalyst] In the examples and comparative examples described later, the hydrogenation catalysts used in preparing the polymers were prepared by the following method. A nitrogen-substituted reaction vessel was charged with 1 L of dried and purified cyclohexane, and 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. With sufficient stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days to obtain a hydrogenation catalyst (T).

[0186] Comparative Example 1: Polymer B1 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 26.3 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 0.103 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 0.080 mmol / min as a polar substance, and n-butyllithium (polymerization initiator n-butyllithium) was added at 0.305 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 78 °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 84°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 modifier at a rate of 0.061 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 modifier to be added to the polymer solution flowing out of the reactor outlet, and the temperature was 76°C. The difference between the temperature during the polymerization process and the temperature before the modifier was added was 8°C. 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 the polymer, and the solvent was then removed by steam stripping to obtain Polymer B1.

[0187] Example 1: Polymer A1 After carrying out the same treatment as in Comparative Example 1 up to the step of reacting the modifier, the resulting conjugated diene polymer solution was transferred to another reactor, and the hydrogenation catalyst (T) prepared above was added in an amount of 50 ppm (Ti basis) per 100 parts by mass of the conjugated diene polymer. 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 resulting hydrogenated conjugated diene polymer was 78%. Thereafter, an antioxidant was added as in Comparative Example 1, and the solvent was removed to obtain Polymer A1.

[0188] [Comparative Examples 2-8: Polymers B2-B8] Polymerization was carried out in the same manner as in Comparative Example 1 except for the differences in the conditions shown in Tables 3 to 5, to obtain polymers B2 to B8.

[0189] Examples 2 to 34: Polymers A2 to A34 Polymerization and hydrogenation were carried out in the same manner as in Example 1, except for the differences in the conditions shown in Tables 1 to 5, to obtain polymers A2 to A34. In Examples 12, 20, and 32, the modifying agents (i) and (ii) shown in Tables 2 to 3 and 5 were added simultaneously and reacted. In Examples 13, 14, 21, 22, 33, and 34, the modifying agent (i) shown in Tables 2 to 3 and 5 was added and reacted, and two minutes later, the modifying agent (ii) was added and reacted. In the hydrogenation reactions in Examples 2 to 34, the amount of hydrogenation catalyst added was kept constant, and the hydrogenation rate was controlled to the values ​​shown in Tables 7 to 11 by adjusting the amount of hydrogen added and the reaction time.

[0190] The modifiers in Tables 1 to 5 are as follows: Compound 1: 2,2-Dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane Compound 2: Tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine Compound 3: N-(trimethoxysilyl)propyl-N'-methyl-piperazine Compound 4: 1,3-dimethyl-2-imidazolidinone

[0191] [Table 1]

[0192] [Table 2]

[0193] [Table 3]

[0194] [Table 4]

[0195] [Table 5]

[0196] [Evaluation of Polymers A1 to A34 and Polymers B1 to B8] Polymers A1 to A34 and polymers B1 to B8 shown in Tables 1 to 5 were used as raw rubbers, and rubber compositions containing the respective raw rubbers were obtained by mixing the components according to the compounding and kneading methods described below. The amount of each compounding ingredient added below is shown in parts by mass per 100 parts by mass of raw rubber not including any rubber softener. (Composition) Raw rubber (polymers A1 to A34 and polymers B1 to B8): 100 parts by mass (oil excluded) Silica (product name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m2 / g): 75.0 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 Softener (JXTG Energy Process Oil PF30 (SRAE Oil)): 30.0 parts by mass Zinc oxide (zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.): 2.5 parts by mass Stearic acid (Kao Corporation's Lunac S-90V): 2.0 parts by weight Wax (Sunnock manufactured by Ouchi Shinko Chemical Co., Ltd.): 1.5 parts by mass Antioxidant (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 1.7 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7 parts by mass Vulcanization accelerator 2 (diphenyl guanidine): 2.0 parts by mass (Kneading method) Using an internal mixer (capacity: 0.5 L) equipped with a temperature control device, the materials other than sulfur and vulcanization accelerator were mixed in the first stage of mixing under the conditions of a filling rate of 65% and a rotor rotation speed of 50 to 90 rpm. At this time, the temperature of the internal mixer was controlled, and the discharge temperature was 150 to 160°C to obtain a compound. Next, in the second stage of mixing, the mixture obtained above was cooled to room temperature and then mixed again to improve the dispersion of the reinforcing filler. In this case, the discharge temperature of the mixture was also adjusted to 150 to 160°C by controlling the temperature of the mixer. After cooling, in the third stage of kneading, a vulcanization accelerator and sulfur were added and kneaded using an open roll set at 70°C to obtain an unvulcanized rubber composition. The unvulcanized rubber composition obtained was then molded and vulcanized in a vulcanization press at 160°C for a predetermined vulcanization time to obtain a vulcanized rubber composition. The vulcanization time was calculated by adding 5 minutes to the 90% vulcanization time of the unvulcanized rubber composition. The vulcanized rubber composition was evaluated by the following methods.

[0197] [Evaluation items and test methods] The unvulcanized and vulcanized rubber compositions obtained were evaluated as follows, and the results are shown in Tables 7 to 11 below.

[0198] <Sheet moldability (processability) of rubber composition> In the above-mentioned kneading method, in the third stage of kneading, sulfur and a vulcanization accelerator were added and kneaded with an open roll set at 70°C 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 holes in the sheet, the more likely it is that breaks will occur during sheet molding, meaning that the processability will be poor. 2 The average number of pores per 1 cm was counted. 2 The above were defined as voids. The measurement result of the rubber composition sheet of the polymer used as the standard for comparison was set as 100, and the results were evaluated using the following indexes. (See Table 6 for the standard polymer.) ○: Index is less than 90 △: Index is 90 or more but less than 120 ×: Index is 120 or more

[0199] <Tensile properties> The vulcanized rubber compositions obtained above were used as samples to measure tensile properties in accordance with the tensile test method of JIS K6251. The measurement results of the vulcanized rubber composition of the reference polymer were set at 100, and the results were evaluated using the following indices (see Table 6 for the reference polymer). Tensile strength ○: Index is 110 or more △: Index is 80 or more and less than 110 ×: Index is less than 80

[0200] <Fuel efficiency> Using the Rheometrics Scientific ARES viscoelasticity tester, tan δ was measured in torsion mode at 50°C, a frequency of 10 Hz, and a strain of 3%, and used as an index of fuel economy. The measurement result of the vulcanized rubber composition of the polymer used as the reference polymer was then set at 100, and the results were evaluated using the following index. (See Table 6 for the reference polymer.) ○: Index is less than 95 △: Index is 95 or more and less than 120 ×: Index is 120 or more

[0201] <Ozone resistance> From the vulcanized rubber composition obtained above, strip samples (6 cm long x 1 cm wide x 2.0 mm thick) were punched out and placed in an ozone tank (40°C, 50 pphm) and tested for 48 hours (dynamic ozone test) under the conditions of the former JIS K6259 (1993) (repetition rate 0.5 Hz, dynamic strain 20%, rotation speed 2 rpm). After that, the strip samples (vulcanized rubber sheets) were observed, and the number of cracks 1 mm or longer on the surface was counted and evaluated according to the following criteria. ○: Number of cracks is less than 10 △: Number of cracks is 10 or more but less than 20 ×: The number of cracks is 20 or more, or the vulcanized rubber sheet is broken

[0202] [Table 6]

[0203] [Table 7]

[0204] [Table 8]

[0205] [Table 9]

[0206] [Table 10]

[0207] [Table 11]

[0208] From Tables 7 to 11, it was confirmed that the polymers of Examples 1 to 34 gave rubber compositions that were excellent in processability, tensile strength, fuel economy, and ozone resistance compared to the "reference polymers" listed in Table 6.

[0209] As described above, it has become clear that by using a hydrogenated conjugated diene-based polymer whose Mooney stress relaxation area, hydrogenation rate, weight average molecular weight, and molecular weight distribution are within specific ranges, it is possible to provide a rubber composition that is excellent in processability, tensile strength, fuel economy, and ozone resistance. [Industrial Applicability]

[0210] The present invention has industrial applicability, for example, in casings such as tire treads and sidewalls, packings and gaskets, sealing materials, vibration-proof rubber, vibration-isolating rubber, vibration-damping materials, conveyor belts, shoe outsoles and midsoles, automotive 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. A hydrogenated conjugated diene polymer that satisfies the following conditions (1) to (4): <Condition (1)> The molecular weight distribution is 1.0 or more and 5.0 or less. <Condition (2)> The weight average molecular weight is 100,000 or more and 3,000,000 or less. <Condition (3)> The hydrogenation rate is between 20% and 99%. <Condition (4)> The Mooney stress relaxation area, expressed by the following formula (1), is 500 MU / s or more. [Equation 1] S, k, a, and t in the formula (1) i , t f is as follows: S: Mooney stress relaxation area (unit: MU / s) k: Mooney viscosity 1 second after stopping the operation of the Mooney viscometer rotor a: Absolute value of Mooney stress relaxation rate t i : Time (seconds) at which Mooney stress relaxation begins t f : Time (seconds) until Mooney stress relaxation is complete

2. 2. The hydrogenated conjugated diene polymer according to claim 1, wherein the Mooney stress relaxation area represented by the formula (1) is 1500 MU / s or more and 4000 MU / s or less.

3. 2. The hydrogenated conjugated diene polymer according to claim 1, wherein the hydrogenation rate is from 60% to 95%.

4. The hydrogenated conjugated diene polymer according to claim 1, which contains 1 mass % or more of aromatic vinyl monomer units.

5. 2. The hydrogenated conjugated diene polymer according to claim 1, wherein the butylene bond content is from 10 mol % to 65 mol %.

6. The hydrogenated conjugated diene polymer according to claim 1, having a Mooney stress relaxation rate of 0.1 or more and 3.0 or less.

7. The hydrogenated conjugated diene polymer according to claim 1, having a nitrogen content of 20 ppm or more.

8. 2. The hydrogenated conjugated diene polymer according to claim 1, having a silicon atom content of 50 ppm or more.

9. The hydrogenated conjugated diene polymer according to claim 1, which has a modification rate of 20% or more.

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