Hydrogenated conjugated diene polymers and methods for producing hydrogenated conjugated diene polymers

Abstract

A hydrogenated conjugated diene polymer that satisfies the following conditions (i)-(iii).　Condition (i): The hydrogenated conjugated diene polymer is a random polymer that includes a conjugated diene monomer unit and may include an aromatic vinyl monomer unit, wherein aromatic vinyl monomer blocks are less than 10 mass% of the hydrogenated conjugated diene polymer.　Condition (ii): The weight average molecular weight is 10×104 to 200×104.　Condition (iii): The molecular weight distribution of an ozonolysis product is 2.1 to 6.0.

Description

[Technical Field]

[0001] This invention relates to hydrogenated conjugated diene polymers and methods for producing hydrogenated conjugated diene polymers. [Background technology]

[0002] Traditionally, rubber products, including tires, have been required to have improved durability, such as ozone resistance and tensile strength, as well as low hysteresis loss. For example, Patent Documents 1 and 2 propose technologies for rubber compositions that incorporate hydrogenated conjugated diene polymers and have improved ozone resistance. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2017 / 014282 [Patent Document 2] Patent No. 6845679 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, as described in Patent Documents 1 and 2, when the hydrogenation process of a conjugated diene polymer is carried out in a batch format, increasing the hydrogenation rate to improve ozone resistance leads to a significant increase in the viscosity of the resulting hydrogenated conjugated diene polymer due to entanglement of polymer chains, resulting in a significant deterioration of the processability of the hydrogenated conjugated diene polymer and the rubber composition. Lowering the molecular weight of the conjugated diene polymer to improve the aforementioned processability worsens its cold flow resistance and reduces its fracture properties. Furthermore, while reducing the hydrogenation rate improves processability, it worsens ozone resistance, fracture properties, and cold flow resistance. On the one hand, by introducing a small amount of an aromatic vinyl monomer block into the conjugated diene polymer, the cold flow resistance (fluidity) and fracture physical properties of the hydrogenated conjugated diene polymer and the rubber composition can be improved. However, in such cases, there is a problem that the low hysteresis loss property deteriorates.

[0005] That is, the hydrogenated conjugated diene polymers and rubber compositions proposed conventionally as described above have a problem that it is difficult to achieve excellent ozone resistance, fracture physical properties, and low hysteresis loss property while ensuring good processability and cold flow resistance.

[0006] Therefore, in the present invention, in view of the problems of the conventional technologies described above, an object is to provide a hydrogenated conjugated diene polymer that can achieve excellent processability, ozone resistance, fracture physical properties, and low hysteresis loss property when formed into a rubber composition while ensuring good processability and cold flow resistance.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the problems of the conventional technologies described above, the present inventors have found that a hydrogenated conjugated diene polymer having a specific amount of aromatic vinyl block, weight average molecular weight, and molecular weight distribution of ozone decomposition products can solve the above problems, and have completed the present invention. That is, the present invention is as follows.

[0008] 〔1〕 A hydrogenated conjugated diene polymer satisfying the following conditions (i) to (iii). <Condition (i)> A random polymer containing conjugated diene monomer units and optionally containing aromatic vinyl monomer units, where the content of the aromatic vinyl monomer block is less than 10% by mass of the hydrogenated conjugated diene polymer. <Condition (ii)> The weight average molecular weight is 10×10 , 4 , , , 4 or more and 200×10 4 or less. <Condition (iii)> The molecular weight distribution of the ozone decomposition product is 2.1 or more and 6.0 or less. 〔2〕 The hydrogenated conjugated diene polymer according to 〔1〕 above, having a hydrogenation rate of 97 mol% or less. 〔3〕 The hydrogenated conjugated diene polymer according to 〔1〕 or 〔2〕 above, having a hydrogenation rate of 50 mol% or more. 〔4〕 The hydrogenated conjugated diene polymer according to any one of 〔1〕 to 〔3〕 above, having an ethylene structure of 1% by mass or more. 〔5〕 The hydrogenated conjugated diene polymer according to any one of 〔1〕 to 〔4〕 above, containing an aromatic vinyl monomer unit. 〔6〕 A method for producing a hydrogenated conjugated diene polymer according to any one of 〔1〕 to 〔5〕 above, having a weight average molecular weight of 10×10 4 or more and 200×10 4 or less, and obtaining a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass in a polymerization step, a hydrogenation step of obtaining a plurality of types of hydrogenated conjugated diene polymers having different hydrogenation rates, a mixing step of mixing the plurality of types of hydrogenated conjugated diene polymers and making the hydrogenation rate distribution HWD represented by the following formula (1) 1.005 or more, which has. A method for producing a hydrogenated conjugated diene polymer. <00001​​​​​​​​​​​​​​​​​​​​A method for producing a hydrogenated conjugated diene polymer according to any one of the above [1] to [5], Weight-average molecular weight is 10 × 10 4 The above 200 x 10 4 The following describes a polymerization step to obtain a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass, A hydrogenation step is performed by adding hydrogen to the aforementioned conjugated diene polymer. It has, The hydrogenation process is a continuous process, and the number of complete mixing tanks N, when the residence time distribution in the reactor is fitted using the impulse response method with a complete mixing tank model, is set to 1.0 to 2.5. A method for producing hydrogenated conjugated diene polymers. [8] A method for producing a hydrogenated conjugated diene polymer according to [7], wherein hydrogen and the conjugated diene polymer are supplied to the reactor of the hydrogenation step from opposing directions, or hydrogen and / or the conjugated diene polymer are supplied from multiple locations. [9] In the continuous process described above, a stirred-tank reactor is used, the conjugated diene polymer and the hydrogenation catalyst are supplied from the top of the stirred-tank reactor, and hydrogen is supplied from the bottom of the stirred-tank reactor while stirring is performed. The hydrogenated conjugated diene polymer is extruded from the bottom of the tank of the aforementioned stirred-tank type reactor. A method for producing a hydrogenated conjugated diene polymer as described in [7] or [8] above. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a hydrogenated conjugated diene polymer that has good processability and cold flow resistance, and also excellent processability, ozone resistance, fracture properties, and low hysteresis loss when used as a rubber composition. [Modes for carrying out the invention]

[0013] The following describes in detail an embodiment for carrying out the present invention (hereinafter referred to as "this embodiment"). Note that the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be appropriately modified and implemented within the scope of its gist.

[0014] [Hydrogenated conjugated diene polymer] The hydrogenated conjugated diene polymer of this embodiment satisfies the following conditions (i) to (iii). <Condition (i)> It is a random polymer containing conjugated diene monomer units and may contain aromatic vinyl monomer units, The content of the aromatic vinyl monomer block is less than 10% by mass of the hydrogenated conjugated diene polymer. <Condition (ii)> The weight average molecular weight is 10×10 4 or more and 200×10 4 or less. <Condition (iii)> The molecular weight distribution of the ozonolysis product is 2.1 or more and 6.0 or less.

[0015] According to the above configuration, the processability and cold flow resistance are good. Further, as will be described later, when the hydrogenated conjugated diene polymer of this embodiment is made into a rubber composition in which other polymers, filler components, plasticizer components, crosslinking agent components, etc. are appropriately combined, it has excellent processability, ozone resistance, fracture physical properties, and low hysteresis loss properties.

[0016] The hydrogenated conjugated diene polymer of this embodiment has a structural unit based on a conjugated diene compound (hereinafter also referred to as "conjugated diene monomer unit") and a structure in which hydrogen is added to a portion polymerized with a conjugated diene as a monomer or a structural unit based on ethylene (hereinafter also referred to as "ethylene structure"). The hydrogenated conjugated diene polymer of this embodiment preferably contains a structural unit based on an aromatic vinyl compound (aromatic vinyl monomer unit). The ethylene structure is formed by subjecting a part of the double bond portion to an ethylene structure by performing a hydrogenation reaction on the conjugated diene monomer unit, or by copolymerizing a conjugated diene compound and ethylene.

[0017] From the viewpoint of manufacturing cost, the hydrogenated conjugated diene polymer of this embodiment is preferably obtained by subjecting the conjugated diene polymer to a hydrogenation reaction. By controlling the hydrogenation rate to a high level, the content of ethylene structures can be increased. In this embodiment, the hydrogenated conjugated diene polymer is defined as having an ethylene structure when hydrogen is added to a polymer chain formed at both ends of the main chain of a conjugated diene monomer unit (for example, the 1,4-bond in a polymer using 1,3-butadiene as a monomer), while other forms (for example, the 1,2-vinyl bond in a polymer using 1,3-butadiene as a monomer) are not included in the ethylene structure.

[0018] The conjugated diene compounds used to form conjugated diene monomer units are not limited to the following, but examples include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene. These may be used individually or in combination of two or more. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of practical aspects such as the availability of monomers, and 1,3-butadiene is more preferred.

[0019] (Condition (i) Content of aromatic vinyl monomer units) The hydrogenated conjugated diene polymer of this embodiment may contain aromatic vinyl monomer units, and the content of aromatic vinyl monomer units in the hydrogenated conjugated diene polymer is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, relative to the total amount of the hydrogenated conjugated diene polymer, from the viewpoint of the breaking strength of the rubber composition. Furthermore, the content of aromatic vinyl monomer units is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the total amount of hydrogenated conjugated diene polymer in this embodiment, from the viewpoint of low hysteresis loss of the rubber composition. The content of aromatic vinyl monomer units can be measured by the method described in the examples below, and the content of aromatic vinyl monomers can be controlled to the above-mentioned numerical range by adjusting the timing, amount, and polymerization time of the addition of the aromatic vinyl compound in the polymerization process of the conjugated diene polymer.

[0020] Aromatic vinyl compounds that form aromatic vinyl monomer units are not limited to the following, but examples include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, and 2,4,6-trimethylstyrene. These may be used individually or in combination of two or more. Among these, styrene is particularly preferred from a practical standpoint, such as the availability of monomers.

[0021] In this embodiment, from the viewpoint of low hysteresis loss in the rubber composition, the hydrogenated conjugated diene polymer has an aromatic vinyl monomer block content (long chain ratio of constituent units based on aromatic vinyl compounds) of less than 10% by mass, preferably 7% by mass or less, and more preferably 5% by mass or less, relative to the total mass of the hydrogenated conjugated diene polymer of this embodiment. Low hysteresis loss in the rubber composition contributes to the fuel efficiency of tires when used as rubber for tires, and also has the advantage of less stress change during repeated deformation when used in industrial products such as cushion rubber. The aromatic vinyl monomer block content in the hydrogenated conjugated diene polymer of this embodiment can be controlled to the above numerical range by adjusting, for example, the amount and timing of addition of the aromatic vinyl compound, the amount of randomizer added, etc., during the polymerization process.

[0022] The hydrogenated conjugated diene polymer of this embodiment is a random polymer from the viewpoint of reducing hysteresis loss in the rubber composition. In this specification, "random polymer" means that the proportion of long chains of aromatic vinyl monomer units is less than 10% by mass of the total mass of the hydrogenated conjugated diene polymer. Here, the proportion of long chains is the ratio of chains of eight or more consecutive structural units (long chains) to the total number of structural units. In this specification, if the "random polymer" is a polymer using two or more types of monomer units, the two or more types of monomer units may be uniformly distributed in the polymer, or they may be distributed in a tapered, step-like, convex, or concave pattern.

[0023] Here, the long-chain ratio of aromatic vinyl monomer units was measured using the hydrogenated conjugated diene polymer of this embodiment with deuterated chloroform as the solvent. 1 This can be obtained by calculating the ratio of the integral value in range (a) to the sum of the integral values ​​in each of the chemical shift S ranges (a) to (c) below using the 1H-NMR spectrum. For example, if the aromatic vinyl monomer is styrene, the ratio of the integral value in range (a) to the sum of the integral values ​​in each of the ranges (a) to (c) can be calculated, and then multiplying this value by 2.5 to determine the proportion of styrene. This allows us to determine the long chain proportion of aromatic vinyl monomer units. (a) Chains of aromatic vinyl monomer units of 8 or more: 6.00 ≤ S < 6.68 (b) Chains of aromatic vinyl monomer units 2-7: 6.68 ≤ S < 6.89 (c) Single chain of aromatic vinyl monomer units: 6.89 ≤ S ≤ 8.00

[0024] As described above, from the viewpoint of low hysteresis loss in the rubber composition, the hydrogenated conjugated diene polymer in this embodiment is a random polymer. Furthermore, the hydrogenated conjugated diene polymer in this embodiment may be modified or unmodified, but from the viewpoint of reinforcing properties and abrasion resistance due to the filler component of the rubber composition, it is preferable that it be a modified random polymer. The modification methods will be described later, but a modified hydrogenated conjugated diene polymer is, for example, a polymer in which a functional group has been introduced to the polymerization termination end using a modifying agent.

[0025] (Amount of ethylene structure and hydrogenation rate) When the hydrogenated conjugated diene polymer of this embodiment is obtained by a hydrogenation reaction with a conjugated diene polymer, from the viewpoint of ozone resistance and tensile strength, the rubber composition containing the hydrogenated conjugated diene polymer of this embodiment preferably has 1% by mass or more of hydrogenated ethylene structures with 1,4-bonds, more preferably 2% by mass or more, and even more preferably 5% by mass or more. Furthermore, the upper limit of the ethylene structure depends on the content of aromatic vinyl monomer units before hydrogenation and the amount of 1,2-vinyl bonds, but from the viewpoint of processability, it is preferably 95% by mass or less, and more preferably 90% by mass or less.

[0026] In the hydrogenated conjugated diene polymer of this embodiment, the amount of ethylene structure can be controlled, for example, in the case of a polymer using styrene and 1,3-butadiene as monomers, by adjusting the ratio of styrene to 1,3-butadiene, the ratio of 1,4-bonds to 1,2-vinyl bonds in the butadiene portion, and the hydrogenation rate. Methods to increase the amount of ethylene structure include reducing the styrene ratio and increasing the butadiene ratio, increasing the 1,4-bond ratio of the butadiene portion, and increasing the hydrogenation rate. Conversely, the amount of ethylene structure can be reduced by increasing the styrene ratio and decreasing the butadiene ratio, decreasing the 1,4-bond ratio of the butadiene portion, and decreasing the hydrogenation rate. For example, in the case of a polymer using 1,3-butadiene as a monomer, polymerization generates 1,4-bonds and 1,2-vinyl bonds. However, when a polymer containing both is hydrogenated, the hydrogenation reaction proceeds faster for the 1,2-vinyl bonds, and they tend to be hydrogenated preferentially. Therefore, in order to "have 1% by mass or more of ethylene structure," it is preferable to first form more than 1% by mass of 1,4-bonds through polymerization, and then to hydrogenate the 1,2-vinyl bonds to the extent that most of them are consumed and more than 1% by mass of 1,4-bonds are hydrogenated, so that 1% by mass or more of ethylene structure is formed. Specifically, it is preferable to set the hydrogenation rate at least 1% higher than the ratio of 1,2-vinyl bonds to the ratio of conjugated diene monomer units, and more preferably at least 2% higher. However, as will be described later, if the hydrogenation rate has a distribution, even with a hydrogenation rate lower than the amount of 1,2-vinyl bonds, 1% by mass or more of the 1,4-bonds may also be hydrogenated. The hydrogenation rate (the percentage of hydrogen added to the conjugated diene portion) is preferably such that the 1,4-bonds are hydrogenated so that the ethylene structure is 1% by mass or more. Depending on the amount of 1,2-vinyl bonds before hydrogenation, a preferred hydrogenation rate is 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more. Furthermore, in order to fully demonstrate the effects of the hydrogenation rate distribution described later, the hydrogenated conjugated diene polymer of this embodiment preferably has a hydrogenation rate of 97 mol% or less, more preferably 93 mol% or less, even more preferably 90 mol% or less, even more preferably 88 mol% or less, and most preferably 85 mol% or less. The hydrogenation rate is 1 It can be calculated from the spectral reduction rate of the unsaturated bond region of the spectrum obtained by measuring 1H-NMR, and when the hydrogen conversion rate has a distribution as described later, it corresponds to the average hydrogenation rate.

[0027] (Weight average molecular weight) The hydrogenated conjugated diene polymer of this embodiment has a weight-average molecular weight (Mw) of 10 × 10, which is desirable from the viewpoint of the tensile strength of the rubber composition. 4 The above is preferable to 15 × 10 4That is all, more 20 × 10 4 That concludes the explanation. Furthermore, the weight-average molecular weight of the hydrogenated conjugated diene polymer is 200 × 10⁻¹⁰, from the viewpoint of processability of the hydrogenated conjugated diene polymer and rubber composition in this embodiment. 4 The following, preferably 100 × 10 4 The following is more 70 × 10 4 The following applies:

[0028] (molecular weight distribution) In this embodiment, the hydrogenated conjugated diene polymer has a molecular weight distribution (Mw / Mn) of 1.1 or higher, more preferably 1.2 or higher, and even more preferably 1.3 or higher, from the viewpoint of processability of the hydrogenated conjugated diene polymer and the rubber composition. Furthermore, the molecular weight distribution of the hydrogenated conjugated diene polymer is preferably 4.0 or lower, more preferably 3.5 or lower, and even more preferably 3.0 or lower, from the viewpoint of low hysteresis loss of the rubber composition. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) can be measured by the method described in the examples below.

[0029] (Molecular weight distribution of ozone decomposition products (hydrogenation rate distribution)) In this embodiment, the hydrogenation rate of the hydrogenated conjugated diene polymer is preferably distributed, from the viewpoint of achieving a high balance between processability, cold flow resistance, ozone resistance, and tensile strength of the rubber composition. When the hydrogenation rate distribution of a hydrogenated conjugated diene polymer is narrow, that is, when the hydrogenation rate is uniform or when the frequency distribution with respect to the hydrogenation rate shows a sharp peak, one possible method to improve the ozone resistance and tensile strength of the rubber composition is to increase the hydrogenation rate, as described in International Publication No. 2014 / 133097. However, when the hydrogenation rate is high, the Mooney viscosity of the resulting hydrogenated conjugated diene polymer tends to increase too much, leading to poor processability. To ensure good processability, it is possible to lower the molecular weight, but lowering the molecular weight leads to a decrease in the tensile strength of the rubber composition, making it difficult to achieve both of these properties simultaneously.

[0030] On the other hand, when the hydrogenation rate of a hydrogenated conjugated diene polymer has a broad distribution, that is, when the frequency distribution with respect to the hydrogenation rate shows a broad peak, low hydrogenation rate components that have excellent processability and crosslinking properties and high hydrogenation rate components that have excellent ozone resistance and tensile properties when used in a rubber composition coexist, allowing for a high degree of balance between these physical properties.

[0031] Furthermore, hydrogenated conjugated diene polymers with a broad hydrogenation rate distribution exhibit superior ozone resistance in rubber compositions compared to hydrogenated conjugated diene polymers with a narrow hydrogenation rate distribution, when compared at the same average hydrogenation rate. This is thought to be because components with a high hydrogenation rate, such as those with many units derived from ethylene structures in their molecular chains, have lower surface free energy than components with a low hydrogenation rate. As a result, when hydrogenated conjugated diene polymers are used in rubber compositions, they tend to segregate on the surface of the rubber composition. This segregation acts as a protective film on the vulcanized product, preventing ozone from penetrating into the vulcanized product and thus preventing deterioration of the vulcanized product.

[0032] The hydrogenation rate distribution of hydrogenated conjugated diene polymers can be indirectly evaluated by the following method. Specifically, the hydrogenation rate distribution of hydrogenated conjugated diene polymers can be evaluated by using the ozonolysis method known as Tanaka et al. (Polymer, 22, 1721 (1981)), which involves decomposing the double bonds in the hydrogenated conjugated diene polymer with ozone, and then analyzing the molecular weight distribution of the decomposition products by GPC (gel permeation chromatography). Specifically, assuming a random copolymer of butadiene and styrene as the hydrogenated conjugated diene polymer in this embodiment, if all double bonds in the conjugated diene polymer are hydrogenated, there are no double bonds that will be cleaved by ozonolysis, so the decomposition product will be only one type of polymer that is not cleaved. On the other hand, if the conjugated diene polymer is not hydrogenated, all parts polymerized by the 1,4-bonds of butadiene are cleaved, so depending on the length of adjacent 1,4-bonds, combinations of decomposition products containing one or more styrene, decomposition products containing one or more styrene and 1,2-bonds, and decomposition products containing only one or more 1,2-bonds will occur. In this case, although the molecular weight distribution of the decomposition products has a certain degree of spread depending on the frequency of 1,4-bonds and the randomness of the styrene, since there are many low molecular weight decomposition products overall, the spread is about 1.8 and does not become larger than 2.1. If the hydrogenation rate distribution of a hydrogenated conjugated diene polymer is broad, it will contain both decomposition products that are close to the uncleaved polymer and decomposition products that are finely cleaved. As a result, the distribution of molecular chain lengths of ozonodecomposition products will also broaden, and therefore the molecular weight distribution of ozonodecomposition products will broaden.

[0033] When the hydrogenation rate distribution of the hydrogenated conjugated diene polymer of this embodiment is evaluated using the molecular weight distribution of the ozone decomposition product described above, the molecular weight distribution of such ozone decomposition product is 2.1 or higher, preferably 2.2 or higher, more preferably 2.3 or higher, even more preferably 2.45 or higher, and even more preferably 2.50 or higher, from the viewpoint of achieving a high balance between the processability and cold flow resistance of the hydrogenated conjugated diene polymer and rubber composition of this embodiment, and the ozone resistance and tensile strength of the rubber composition. The molecular weight distribution of the ozone decomposition products being 2.1 or higher means that the hydrogenation rate distribution of the hydrogenated conjugated diene polymer in this embodiment is relatively broad, allowing for a balance between the processability and cold flow resistance of the hydrogenated conjugated diene polymer and rubber composition in this embodiment, as well as the ozone resistance and tensile strength of the rubber composition. Furthermore, the molecular weight distribution of the ozone decomposition products is 6.0 or less, preferably 5.7 or less, more preferably 5.5 or less, even more preferably 5.0 or less, and even more preferably 4.7 or less, from the viewpoint of fully exhibiting the ozone resistance and tensile strength of the rubber composition. By setting the molecular weight distribution of ozone decomposition products to 6.0 or less, it becomes less likely for components with very low hydrogenation rates to be included, and the ozone resistance and tensile strength of the rubber composition can be fully expressed.

[0034] The molecular weight distribution of the hydrogenated conjugated diene polymer has little effect on the molecular weight distribution of the ozonolysis products described above. This is because the hydrogenated conjugated diene polymer of this embodiment contains less than 10% by mass of aromatic vinyl monomer blocks, meaning there are few or no aromatic vinyl monomer blocks that are not decomposed by ozonolysis, and also because the molecular chain length after ozonolysis is not affected by the molecular chain length before ozonolysis. The molecular weight distribution of ozone decomposition products can be controlled to the above-mentioned numerical range by adjusting, for example, the distribution of 1,2- and 1,4- bonds in the hydrogenated conjugated diene polymer of this embodiment, and the distribution of the hydrogenation rate. Specifically, this can be done by assigning a distribution to the 1,2- and 1,4- bonds, or by assigning a distribution to the hydrogenation rate in the hydrogenated conjugated diene polymer of this embodiment, as will be described later.

[0035] In this embodiment, the hydrogenated conjugated diene polymer, as measured by GPC (gel permeation chromatography) after decomposition by the ozonolysis method described above, has an area ratio S to the peak top molecular weight of the ozonolysis product represented by the following formula (I). From the viewpoint of achieving a high balance between the processability and cold flow resistance of the hydrogenated conjugated diene polymer and the rubber composition, and the ozone resistance and tensile strength of the rubber composition, the S is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less. Area ratio to peak top molecular weight of ozone decomposition product S = A / B × 100 ... (I) A: Peak area from molecular weight 200 to peak top molecular weight of GPC, an ozone decomposition product. B: Area of ​​the entire peak of GPC with a molecular weight of 200 or more in ozone decomposition products

[0036] [Method for producing hydrogenated conjugated diene polymers] The hydrogenated conjugated diene polymer of this embodiment can be produced, for example, by a method comprising a polymerization step of polymerizing a conjugated diene compound and an aromatic vinyl compound, and a hydrogenation step of subjecting the conjugated diene polymer obtained by the polymerization step to a hydrogenation reaction; or by a method comprising a polymerization step of copolymerizing a conjugated diene compound, ethylene, and an aromatic vinyl compound. To form the aforementioned ethylene structure, a hydrogenation step may be performed, or ethylene may be copolymerized in the polymerization step. Furthermore, even when ethylene is copolymerized in the polymerization step, a hydrogenation step may also be performed. Furthermore, if necessary, the modification process described later may be performed. In the polymerization process, the weight-average molecular weight is 10 × 10 4 The above 200 x 10 4 The following describes the polymerization of a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass.

[0037] (Polymerization process) The polymerization process can be carried out by solution polymerization. The monomer concentration in the solution is preferably 5% by mass or more, and more preferably 10% by mass or more. A monomer concentration of 5% by mass or more in the solution tends to increase the amount of conjugated diene polymer obtained and reduce costs. Alternatively, the monomer concentration in the solution is preferably 50% by mass or less, and more preferably 30% by mass or less. A monomer concentration of 50% by mass or less in the solution tends to further reduce the viscosity of the solution, improve stirring efficiency, and facilitate polymerization.

[0038] When anionic polymerization is performed in the polymerization process, there are no particular restrictions on the polymerization initiator, but organolithium compounds are preferably used. Examples of organolithium compounds include, but are not limited to, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, and reaction products of diisopropenylbenzene and butyllithium. Among these, those having an alkyl group with 2 to 20 carbon atoms are preferred, and n-butyllithium or sec-butyllithium are preferred from the viewpoint of availability and safety.

[0039] Furthermore, when coordination polymerization is performed in the polymerization process, it is preferable to use the polymerization catalyst composition described in Japanese Patent Application Publication No. 2020-45500 as the polymerization initiator.

[0040] The method for producing a conjugated diene polymer by anionic polymerization or coordination polymerization using a polymerization initiator is not particularly limited, and conventionally known methods can be used. Specifically, the desired conjugated diene polymer can be obtained by polymerizing styrene, 1,3-butadiene, ethylene, etc., in a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound that is inert to the reaction, using, for example, butyllithium as a polymerization initiator, and optionally in the presence of a predetermined randomizer.

[0041] As the hydrocarbon solvent, hydrocarbon solvents having 3 to 8 carbon atoms are preferred. Examples of such solvents, though not limited to the following, include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, and ethylbenzene. These may be used individually or in combination of two or more types.

[0042] The aforementioned randomizer is a compound that has the effect of controlling the microstructure of the conjugated diene portion in a conjugated diene polymer, for example, increasing the 1,2-vinyl bond in butadiene or the 3,4-bond in isoprene, or controlling the compositional distribution of monomer units in a conjugated diene polymer, for example, randomizing the styrene units and butadiene units in a styrene-butadiene copolymer.

[0043] There are no particular restrictions on the randomizer, and any known compound that is commonly used as a randomizer can be used. The randomizer is not limited to the following, but examples include ethers such as dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(2-tetrahydrofuryl)propane, triethylamine, pyridine, N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, and 1,2-dipiperidinoethane, as well as tertiary amines. Potassium salts such as potassium-t-amilate and potassium-t-butoxide, and sodium salts such as sodium-t-amilate can also be used. These randomizers may be used individually or in combination of two or more.

[0044] Furthermore, the amount of randomizer used is preferably 0.01 molar equivalents or more, and more preferably 0.05 molar equivalents or more, per mole of polymerization initiator. Using 0.01 molar equivalents or more of randomizer per mole of polymerization initiator tends to increase the likelihood of randomization. Furthermore, the amount of randomizer used is preferably 1000 molar equivalents or less, and more preferably 500 molar equivalents or less, per mole of polymerization initiator. Using 1000 molar equivalents or less of randomizer per mole of polymerization initiator tends to reduce the change in monomer reaction rate, thus suppressing the tendency for randomization to become less likely.

[0045] The reaction temperature during the polymerization process is not particularly limited as long as the reaction proceeds smoothly, but it is generally preferably 10°C to 130°C, and more preferably 25°C to 110°C.

[0046] (Modification process) Furthermore, the method for producing a hydrogenated conjugated diene polymer of this embodiment may include a modification step after the polymerization step described above, in which the obtained conjugated diene polymer is modified. When performing a modification step, it is preferable to add a conjugated diene compound at the end of the polymerization step to form conjugated diene monomer units at the polymerization ends. This tends to allow the reaction with the modification agent to proceed more favorably.

[0047] The modification step is, for example, a step in which the active end of a conjugated diene polymer obtained by the polymerization step is reacted with a compound having a functional group that interacts with silica and / or carbon black. The modification process allows for the introduction of functional groups that interact with silica and / or carbon black at the polymerization termination ends of the conjugated diene polymer, resulting in a conjugated diene polymer with modified polymerization termination ends. The term "terminus" refers to the portion of the molecular chain other than the structure derived from the monomer having a carbon-carbon double bond.

[0048] In the modification step, the active end of the conjugated diene polymer obtained in the polymerization step is reacted with a compound having a functional group that interacts with silica and / or carbon black. Furthermore, by performing polymerization using a polymerization initiator that has a functional group in its molecule that interacts with silica and / or carbon black, a functional group can be introduced to the starting end of the conjugated diene polymer. Additionally, if necessary, functional groups can be introduced to both the starting and ending ends.

[0049] The conjugated diene polymer used in the modification reaction (hereinafter also referred to as the "end modification reaction") may have an active end, and may have an unmodified polymerization initiation end or a modified polymerization initiation end. Furthermore, the compound having the functional group is not particularly limited as long as it has a functional group that interacts with silica and / or carbon black and can react with the polymerization active end of the conjugated diene polymer. However, as a specific modification reaction using these conjugated diene polymers and compounds having functional groups, a method of introducing a functional group into the conjugated diene polymer using an end modification agent containing a tin atom or a nitrogen atom is preferred, and a method of introducing a functional group into the conjugated diene polymer using an end modification agent containing a nitrogen atom is more preferred.

[0050] From the viewpoint of polymerization productivity and high modification rate, preferred terminal modifiers containing nitrogen atoms include, for example, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen group-containing carbonyl compounds, nitrogen group-containing vinyl compounds, nitrogen group-containing epoxy compounds, nitrogen group-containing alkoxysilane compounds, and cyclic urea compounds. In particular, nitrogen group-containing alkoxysilane compounds and cyclic urea compounds are more preferred from the viewpoint of polymerization productivity, high modification rate, and reinforcement by fillers. These denaturing agents may be used individually or in combination of two or more.

[0051] The nitrogen-containing alkoxysilane compounds are not limited to the following, but include, for example, 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, and 2,2-dimethoxy-1-(3- (Dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane, 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-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2-ethoxy Xy-2-ethyl-1-(3-diethoxyethylsilylpropyl)-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-aza Examples include -2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N1-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N1-methyl-N3-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0052] Examples of cyclic urea compounds 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, 1,3-dihydro-1,3-dimethyl-2H-imidazole-2-one, 1,3-diethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-propyl-2-imidazolidinone, and 1-methyl-3-butyl-2-imidazolidinone.

[0053] The end-modification reaction of conjugated diene polymers can be carried out, for example, as a solution reaction. This solution reaction may be carried out using a solution containing unreacted monomers after the polymerization reaction is complete in the polymerization step, or the conjugated diene polymer contained in the solution may be isolated and dissolved in a suitable solvent such as cyclohexane before the reaction. Furthermore, the end-modification reaction may be carried out using a batch method, a continuous method, or a combination thereof. In this case, the method of adding the end-modifier is not particularly limited and may be a single addition, a divided addition method, or a continuous addition method.

[0054] The amount of terminal modifier used in the terminal modification reaction can be appropriately set depending on the type of terminal modifier used in the reaction, but it is preferably 0.1 molar equivalents or more, more preferably 0.3 molar equivalents or more, relative to the metal atoms in the polymerization initiator that are involved in the polymerization reaction. By setting the amount to 0.1 molar equivalents or more, the modification reaction can proceed sufficiently, and it can suitably interact with filler components such as silica and carbon black, and suitably improve the dispersibility of the filler components.

[0055] The temperature of the terminal modification reaction is usually the same as the temperature of the polymerization reaction described above, preferably -20 to 150°C, more preferably 0 to 120°C, and particularly preferably 20 to 100°C. The higher the temperature of the modification reaction, the lower the viscosity of the modified conjugated diene polymer tends to be. On the other hand, the lower the temperature of the modification reaction, the less likely the polymerization active ends are to be deactivated. The reaction time for the modification reaction is preferably 5 seconds to 1 hour, more preferably 10 seconds to 45 minutes, and even more preferably 15 seconds to 30 minutes.

[0056] (Stopping the polymerization reaction) The polymerization step in the above-described method for producing hydrogenated conjugated diene polymers can be stopped by adding reaction stoppers commonly used in this field. Examples of such reaction stoppers include alcohols such as methanol, ethanol, and isopropanol, or polar solvents having active protons such as acetic acid, and mixtures thereof, or mixtures of these polar solvents with nonpolar solvents such as hexane and cyclohexane. The amount of reaction stopper added is usually sufficient to be the same molar amount as the anionic polymerization initiator, or about twice the molar amount.

[0057] (Hydrogenation process) When producing the hydrogenated conjugated diene polymer of this embodiment by hydrogenation of the conjugated diene polymer, there are no particular limitations on the hydrogenation method or reaction conditions, and it can be carried out using known methods and conditions. Typically, hydrogenation reactions can be carried out at 20-150°C, under a hydrogen pressure of 0.1-10 MPa, and in the presence of a hydrogenation catalyst. The hydrogenation rate of the hydrogenated conjugated diene polymer in this embodiment can be controlled by adjusting the amount and type of hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, the reaction time, etc.

[0058] The hydrogenation reaction process can be batch-type, continuous-type, or a combination thereof. However, in order to achieve a molecular weight distribution of 2.1 to 6.0 for the ozonolysis products of the hydrogenated conjugated diene polymer in this embodiment, it is necessary to impart a distribution to the hydrogenation rate. Methods for imparting a distribution to the hydrogenation rate include, for example, obtaining multiple types of hydrogenated conjugated diene polymers with different hydrogenation rates, and further mixing these multiple types of hydrogenated conjugated diene copolymers, or making the hydrogenation process a continuous process and controlling the residence time distribution in the reactor where the hydrogenation process is carried out.

[0059] When multiple types of hydrogenated conjugated diene polymers with different hydrogenation rates are obtained and mixed, the hydrogenation rate distribution HWD of the resulting hydrogenated conjugated diene polymers can be expressed by the following equation (1).

[0060]

number

[0061] In formula (1) above, n represents the total number of hydrogenated conjugated diene polymers having different hydrogenation rates, and w i Among them, a specific hydrogenation rate H i This represents the mass fraction of the hydrogenated conjugated diene polymer containing the specified compound within the total hydrogenated conjugated diene polymers.

[0062] The hydrogenation rate distribution (HWD) of the resulting hydrogenated conjugated diene polymer and the molecular weight distribution of the ozonodecomposition products depend on their microstructure, the standard hydrogenation rate, and the mixing ratio of multiple types of hydrogenated conjugated diene polymers. For example, if a conjugated diene polymer with a styrene content of 8% by mass and a 1,2-vinyl bond content of 40% is hydrogenated, and hydrogenated conjugated diene polymers with hydrogenation rates that differ by 20% on the high-hydrogenation side and low-hydrogenation side, respectively, are mixed in equal amounts, the hydrogenation rate distribution (HWD) will be 1.02 to 1.1, and the molecular weight distribution of the ozonodecomposition products will be approximately 2.2 to 4.5. Furthermore, when a conjugated diene polymer similar to that described above is hydrogenated, and hydrogenated conjugated diene polymers with hydrogenation rates that are 10% different on the high-hydrogenation side and low-hydrogenation side relative to a standard hydrogenation rate are mixed in equal proportions, the hydrogenation rate distribution HWD becomes 1.005 to 1.02, and the molecular weight distribution of the ozonodecomposition products becomes approximately 2.1 to 3.5. By employing a method that broadens the hydrogenation rate distribution, the molecular weight distribution of the ozonodecomposition products of the hydrogenated conjugated diene polymer can be controlled to 2.1 to 6.0. By setting the hydrogenation rate distribution HWD to 1.005 or higher and controlling the molecular weight distribution of the ozonodecomposition products of the hydrogenated conjugated diene polymer to a numerical range of 2.1 to 6.0, it tends to be possible to obtain a hydrogenated conjugated diene polymer that has a highly balanced cold flow resistance, ozone resistance, and tensile strength.

[0063] When the hydrogenation process is carried out as a continuous process, the distribution range of the hydrogenation rate of the hydrogenated conjugated diene polymer can be controlled by adjusting the reaction time distribution (residence time distribution) by adjusting the solution viscosity, the amount of solution in the reactor, and the stirring conditions, or by changing the number of supply ports of the conjugated diene polymer to the continuous hydrogenation reactor and thereby changing the flow path through which the conjugated diene polymer passes. As an indicator of the reaction time distribution (residence time distribution), there is the value of N, which is expressed using a complete mixing tank series model that assumes N complete mixing tanks of equal volume are connected in series. It is preferable to reduce the value of N and approach complete mixing. Specifically, complete mixing can be approached by reducing the value of N, such as by lowering the solution viscosity, increasing the stirring speed, or lowering the H / D value, which is the ratio of the liquid level (H) to the reactor diameter (D). More specifically, when performing the hydrogenation process in a continuous process, by setting the number of complete mixing tanks N to 1.0 to 2.5 when fitting the residence time distribution in the reactor using the impulse response method with a complete mixing tank model, the distribution range of the hydrogenation rate of the resulting hydrogenated conjugated diene polymer can be broadened, the molecular weight distribution of the ozone decomposition products of the hydrogenated conjugated diene polymer can be controlled to a numerical range of 2.1 to 6.0, and a hydrogenated conjugated diene polymer with a highly balanced cold flow resistance, ozone resistance, and tensile strength can be obtained.

[0064] In addition to the methods described above, other techniques for adjusting the reaction time distribution and broadening the range of hydrogenation rates include, for example, methods (1) and (2). (1) Method: A method of supplying hydrogen and a conjugated diene polymer to a reactor performing the hydrogenation step from opposing directions. (2) Method: A method of supplying hydrogen and / or a conjugated diene polymer from multiple locations.

[0065] In the case of method (1) described above, for example, a more preferred method for broadening the reaction time distribution so that the hydrogenation rate distribution is broadened is to supply the conjugated diene polymer solution and the hydrogenation catalyst from the top of the tank of the stirred tank reactor, and stir while continuously supplying hydrogen from the bottom of the tank of the stirred tank reactor, thereby pushing the solution out from the bottom of the tank of the stirred tank reactor by the continuous supply. In the case of method (2) described above, a preferred method is to provide multiple supply ports for the conjugated diene polymer to the reactor in a continuous hydrogenation reaction process that broadens the reaction time distribution, continuously supplying 80% of the total amount of polymer from the top of the reactor, continuously supplying 20% ​​of the total amount from the middle of the reactor, and continuously removing the entire amount of polymer after the hydrogenation reaction from the bottom of the reactor.

[0066] In the cases of methods (1) and (2) described above, the value of N in the complete mixing tank row model described above will be approximately 1.0 to 1.8, depending on the L / D ratio of the reactor carrying out the hydrogenation reaction (L: reactor height, D: reactor diameter), the shape and rotation speed of the stirring blades, and the viscosity of the solution. The molecular weight distribution of the ozonodecomposition products of the resulting hydrogenated conjugated diene polymer will be approximately 2.3 to 6.0, depending on the microstructure and the standard hydrogenation rate.

[0067] In addition, in the continuous process of the hydrogenation step, a method can be employed in which a stirred tank reactor is used, and the conjugated diene polymer solution, a homogeneous hydrogenation catalyst, and hydrogen are continuously supplied to the bottom of the stirred tank reactor while being stirred to fill the inside of the reactor, and the hydrogenated conjugated diene polymer is pushed out from the top of the stirred tank reactor by the continuous supply of these polymer solutions, hydrogenation catalysts, and hydrogen.

[0068] Specific methods for adjusting stirring conditions to broaden the reaction time distribution of the hydrogenation reaction include using a backmix reactor with a stirred tank type reactor and vigorously mixing with a stirrer, preferably using a fully mixed reactor. This method allows for a reduction in the number of N when the continuous hydrogenation reaction process is represented by a series of fully mixed tanks, thereby widening the reaction time distribution and obtaining a hydrogenated conjugated diene polymer with a broad hydrogenation rate distribution. For fitting the number N of complete mixing tank rows, known methods such as the impulse response method or step response method described in the Chemical Engineering Handbook can be used.

[0069] Typically, compounds containing any of the metals from groups 4 to 11 of the periodic table can be used as hydrogenation catalysts. For example, compounds containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, and Pt atoms can be used as hydrogenation catalysts. More specific examples of hydrogenation catalysts include metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, and Re; supported heterogeneous catalysts in which metals such as Pd, Ni, Pt, Rh, and Ru are supported on carriers such as carbon, silica, alumina, and diatomaceous earth; homogeneous Ziegler-type catalysts combining organic salts or acetylacetone salts of metal elements such as Ni and Co with reducing agents such as organoaluminum; organometallic compounds or complexes such as Ru and Rh; and hydrogen-adsorbed fullerenes and carbon nanotubes.

[0070] Of these, metallocene compounds containing any of Ti, Zr, Hf, Co, or Ni are preferred because they can undergo hydrogenation in a homogeneous system in an inert organic solvent. Furthermore, metallocene compounds containing any of Ti, Zr, or Hf are preferred. Hydrogenated catalysts may be used individually or in combination of two or more types.

[0071] A preferred method for obtaining hydrogenated conjugated diene polymers is to perform solution polymerization, modify the resulting polymer solution as is, and then subject it to a hydrogenation step as needed. Furthermore, since the hydrogenation reaction generally increases the viscosity of the solution, a step of diluting the solution with a solvent to reduce its viscosity beforehand may be added depending on the application process.

[0072] (Solvent removal process) Hydrogenated conjugated diene polymers are obtained by removing the solvent from the polymer solution obtained above and isolating the polymer. Methods for isolating hydrogenated conjugated diene polymers include, for example, known desolvation methods such as steam stripping, and drying operations such as heat treatment using a dehydration extruder, drying extruder, or conveyor.

[0073] [Rubber composition] The hydrogenated conjugated diene polymer of this embodiment can be combined with other polymers, filler components, plasticizer components, crosslinking agents, etc., to produce a rubber composition with desired properties.

[0074] Other polymers include, but are not limited to, natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), etc. These may be used individually or in combination of two or more.

[0075] Filler components are added to the rubber composition for the purpose of reinforcing the rubber, and are not limited to the following, but include, for example, white fillers (inorganic fillers) such as silica, calcium carbonate, mica, aluminum hydroxide, magnesium oxide, clay, talc, alumina, titanium dioxide, and mica, as well as carbon black. These may be used individually or in combination of two or more. Silica and carbon black are particularly preferred.

[0076] From the viewpoint of the tensile strength of the rubber composition, the content of the filler is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, per 100 parts by mass of the rubber component consisting of the hydrogenated conjugated diene polymer and other polymers of this embodiment. Furthermore, when silica is used as a filler, the silica content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, from the viewpoint of processability and low hysteresis loss.

[0077] The silica used is not particularly limited; for example, dry-process silica (anhydrous silica) and wet-process silica (hydrated silica) can be used. However, wet-process silica is preferred because it contains a large number of silanol groups.

[0078] From the viewpoint of the abrasion resistance of the rubber composition, silica is preferably 60 m² in terms of nitrogen adsorption specific surface area (N2SA). 2 / g or more, more preferably 120m 2 The value is 1 / g or more, and from the viewpoint of low fuel consumption of the rubber composition, it is preferably 300m 2 / g or less, more preferably 200m 2 The value is less than / g. The specific surface area of ​​silica for nitrogen adsorption is measured by the BET method in accordance with ASTM D3037-81.

[0079] Examples of carbon black include, but are not limited to, furnace blacks (furnace carbon blacks) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal blacks (thermal carbon blacks) such as FT and MT; channel blacks (channel carbon blacks) such as EPC, MPC, and CC; and graphite. These may be used individually or in combination of two or more types.

[0080] The nitrogen adsorption specific surface area (N2SA) of carbon black is typically 5-200 m². 2 The value is / g, and from the viewpoint of abrasion resistance of the rubber composition, it is preferably 30m 2 / g or more, comfortably 50m 2 It is 150m or more, and from the viewpoint of low fuel consumption of the rubber composition, it is preferably 150m 2 / g or less, more preferably 120m 2 The nitrogen adsorption specific surface area of ​​carbon black is less than / g. The specific surface area of ​​carbon black is measured according to ASTM D4820-93.

[0081] Furthermore, the dibutyl phthalate (DBP) absorption of carbon black is typically 5 to 300 mL / 100g, with a lower limit of 80 mL / 100g or more and an upper limit of 180 mL / 100g or less. The DBP absorption of carbon black is measured according to ASTM D2414-93.

[0082] Silica is preferably used in combination with a silane coupling agent. Conventionally known silane coupling agents can be used. Examples include, but are not limited to, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, and bis(3-trimethoxysilylpropyl)disulfide. Sulfide-based silane coupling agents such as 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and 3-trimethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptopropyltrimethoxysilane Mercapto compounds such as ptethyltrimethoxysilane and 2-mercaptoethyltriethoxysilane; vinyl silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane; γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Examples include glycidoxy silane coupling agents such as propyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane; nitro silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro silane coupling agents such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. The silane coupling agent may be used alone or in combination of two or more types. Sulfide-based silane coupling agents are particularly preferred from the viewpoint of coupling effect, processability, and cost, and bis(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide are more preferred. From the viewpoint of low fuel consumption and wear resistance of the rubber composition, the content of the silane coupling agent is preferably 3 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of silica. Furthermore, from the viewpoint of processability and cost of the rubber composition, the content of the silane coupling agent is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of silica.

[0083] Examples of plasticizer components include, but are not limited to, drawable oils, resins other than the polymers mentioned above, antioxidants, waxes, stearic acid, and vulcanization accelerators. These may be used individually or in combination of two or more.

[0084] Examples of spreadable oils include, but are not limited to, aromatic mineral oils (viscosity-specific gravity constant (VGC value) 0.900 to 1.049), naphthenic mineral oils (VGC value 0.850 to 0.899), and paraffinic mineral oils (VGC value 0.790 to 0.849). The polycyclic aromatic content of the spreadable oil is preferably less than 3% by mass, and more preferably less than 1% by mass. The polycyclic aromatic content of the spreadable oil can be measured according to the British Petroleum Institute 346 / 92 method. The aromatic compound content (CA) of the spreadable oil is preferably 20% by mass or more. The spreadable oil may be used alone or in combination of two or more types. From the viewpoint of Mooney viscosity, the content of the stretching oil is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of low hysteresis loss and hardness of the rubber composition, the content of the stretching oil is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less, per 100 parts by mass of the rubber component.

[0085] Examples of resins include, but are not limited to, C5 petroleum resins, C9 petroleum resins, coumarone indene resins, indene resins, phenolic resins, and copolymers of α-methylstyrene and / or styrene. These may be used individually or in combination of two or more. Copolymers of coumarone indene resin, phenolic resins (especially terpene phenolic resins), α-methylstyrene and / or styrene are particularly preferred, and copolymers of α-methylstyrene and styrene are more preferred. From the viewpoint of the wet grip performance of the rubber composition, the resin content is preferably 1 part by mass or more, and more preferably 3 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of low hysteresis loss of the rubber composition, the resin content is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the rubber component.

[0086] Anti-aging agents include, but are not limited to, naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-phenyl-N'-isopropyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and N,N'-di-2-naphthyl-p-phenyl Examples include p-phenylenediamine-based antioxidants such as phenylenediamine; quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. These may be used individually or in combination of two or more. In particular, p-phenylenediamine-based antioxidants are preferred, and N-phenyl-N'-isopropyl-p-phenylenediamine is more preferred. The amount of the anti-aging agent is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0087] Examples of waxes include, but are not limited to, petroleum-based waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant-based waxes and animal-based waxes; and synthetic waxes such as polymers of ethylene and propylene. These can be used individually or in combination of two or more. Petroleum-based waxes are particularly preferred, and paraffin waxes are more preferred. The wax content is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, per 100 parts by mass of rubber component.

[0088] As stearic acid, conventionally known products can be used, and are not limited to those listed below, but examples include products from NOF Corporation, NOF Corporation, Kao Corporation, Wako Pure Chemical Industries Ltd., Chiba Fatty Acid Co., Ltd., etc. These may be used individually or in combination of two or more types. The stearic acid content is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0089] Examples of vulcanization accelerators include, but are not limited to, thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, dibenzothiadyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotrilguanidine, and orthotrilbiguanidine. These may be used individually or in combination of two or more. In particular, sulfenamide-based vulcanization accelerators are preferred, and N-cyclohexyl-2-benzothiazole sulfenamide is more preferred, because the effects of this embodiment can be more favorably obtained. Furthermore, it is also preferable to use a guanidine-based vulcanization accelerator in combination. The amount of vulcanization accelerator is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0090] The crosslinking agent component is not limited to the following, but can be appropriately selected depending on the purpose. Examples include sulfur-based crosslinking agents, organic peroxide-based crosslinking agents, inorganic crosslinking agents, polyamine crosslinking agents, resin crosslinking agents, sulfur compound-based crosslinking agents, oxymo-nitrosamine-based crosslinking agents, etc. These may be used individually or in combination of two or more. In particular, sulfur-based crosslinking agents are preferred, and sulfur is more preferred, because the effects of this embodiment can be more favorably obtained. The crosslinking agent content in the rubber composition of this embodiment is preferably 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of rubber component. 0.1 parts by mass or more is preferred, 0.5 parts by mass or more is more preferred, and 1.5 parts by mass or more is even more preferred. Also, 20 parts by mass or less is preferred, 5 parts by mass or less is more preferred, and 3 parts by mass or less is even more preferred. This allows the effects of this embodiment to be more favorably obtained.

[0091] In the rubber composition of this embodiment, a vulcanization accelerator may also be used in combination. Examples of the aforementioned vulcanization accelerators include compounds such as guanidine, aldehyde amine, aldehyde ammonia, thiazole, sulfenamide, thiourea, thiuram, dithiocarbamate, and xantate compounds.

[0092] Furthermore, the rubber composition of this embodiment may also contain various additives other than those described above, such as other softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants. Other known softeners can be used. Other fillers include, for example, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as the heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant.

[0093] (Method for manufacturing rubber composition) The rubber composition containing the hydrogenated conjugated diene polymer of this embodiment can be manufactured by general methods. For example, it can be manufactured by kneading each component in a Banbury mixer, kneader, open roll, etc., and then vulcanizing it. [Examples]

[0094] The present invention will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples. The various physical properties in the examples and comparative examples were measured by the methods described below and further evaluated by the methods described later.

[0095] [Physical property measurement method] (Amount of styrene bound in conjugated diene polymers) 100 mg of the sample before hydrogenation was dissolved in 100 mL of chloroform to prepare the measurement sample. The amount of bound styrene (mass%) relative to 100% by mass of the conjugated diene polymer sample was measured by the amount of ultraviolet absorption at the phenyl group of styrene (around 254 nm). The measurement device used was the "UV-2450" spectrophotometer manufactured by Shimadzu Corporation.

[0096] (Amount of 1,2-vinyl bonds in the butadiene portion of conjugated diene polymers) 50 mg of the sample before hydrogenation was dissolved in 10 mL of carbon disulfide to prepare the measurement sample. Using a solution cell, the infrared spectrum is measured at 600-1000 cm⁻¹. -1Measurements were taken within a specified range, and the microstructure of the butadiene moiety, i.e., the amount of 1,2-vinyl bonds (mol%), was determined by the Hampton method (as described in RRHampton, Analytical Chemistry 21,923 (1949)) based on the absorbance at a predetermined wavenumber. A Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation was used as the measuring instrument.

[0097] (Weight-average molecular weight (Mw) and molecular weight distribution of hydrogenated conjugated diene polymers and ozonolysis products) Using a GPC measuring device with three columns packed with polystyrene gel, chromatograms were measured, and the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of hydrogenated conjugated diene polymers and ozonodecomposition products were determined based on a calibration curve using standard polystyrene. Furthermore, the molecular weight distribution (Mw / Mn) of ozonolysis products of hydrogenated conjugated diene polymers was limited to the range of polystyrene-based molecular weights of 200 or more. The specific measurement conditions are shown below. The following 20 μL of measurement solution was injected into the GPC measuring device and measurements were performed. <Measurement conditions> Eluent: 5 mmol / L tetrahydrofuran (THF) containing triethylamine Guard column: Product name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation. Separation column: A combination of TSKgel SuperH5000, TSKgel SuperH6000, and TSKgel SuperH7000, manufactured by Tosoh Corporation, linked together in that order. Oven temperature: 40℃ Flow rate: 0.6mL / min Detector: RI detector (product name "HLC8020" manufactured by Tosoh Corporation) Measurement solution: A measurement solution prepared by dissolving 10 mg of the sample for measurement in 20 mL of THF. <Method for producing ozonolysis products of hydrogenated conjugated diene polymers> A sample solution prepared by dissolving 100 mg of hydrogenated conjugated diene polymer in 100 mL of dichloromethane was cooled to -30°C. While cooling, 2% ozone (O3) oxygen, prepared using an ozone generator, was passed through the sample solution at a rate of 150 mL / min. The gas exiting the sample solution was then passed through a detection solution (75 mL of 3% potassium iodide aqueous solution with 6 drops of 3% starch aqueous solution added). One minute after the detection solution turned yellow, the oxygen flow was stopped to obtain the ozonide sample solution. The obtained ozonide sample solution was added dropwise at a rate of 6 mL / min to 50 mL of diethyl ether mixed with 0.5 g of lithium aluminum hydride under a nitrogen atmosphere while cooling to -30°C. The sample solution was then refluxed at 50°C for 15 minutes to carry out the reduction reaction. Next, 3 mL of pure water was added dropwise to the sample solution at a rate of 3 mL / min while cooling to -30°C to hydrolyze it. Then, 3 g of potassium carbonate was added, followed by salting out and filtration. The solvent of the resulting filtrate was removed using an evaporator to obtain the ozonolysis product of the hydrogenated conjugated diene polymer.

[0098] (Area ratio S to the peak top molecular weight of ozonolysis products of hydrogenated conjugated diene polymers) From the GPC (gel permeation chromatography) obtained after decomposition by the ozonolysis method described above, the area ratio S to the peak top molecular weight of the ozonolysis product was calculated using the following formula (I), and this value was evaluated using the following indicators. ○: The area ratio S calculated using formula (I) is 40% or less. ×: The area ratio S calculated using formula (I) is greater than 40% Area ratio to peak top molecular weight of ozone decomposition product S = A / B × 100 ... (I) A: Peak area from molecular weight 200 to peak top molecular weight of GPC, an ozone decomposition product. B: Area of ​​the entire peak of GPC with a molecular weight of 200 or more in ozone decomposition products

[0099] (Hydrogenation rate of hydrogenated conjugated diene polymers) 1The cumulative value of the unsaturated bonds of the conjugated diene polymer before hydrogenation was obtained by 1H-NMR measurement. Next, the hydrogenated conjugated diene polymer was precipitated and recovered by adding a large amount of methanol to the reaction solution after the hydrogenation reaction. Then, the hydrogenated conjugated diene polymer was extracted with acetone and vacuum-dried. This was then used to obtain the hydrogenated conjugated diene polymer. 1 The hydrogenation rate was measured using the sample for 1H-NMR measurement. The measurement conditions are described below. <Measurement conditions> Measuring instrument: JNM-LA400 (manufactured by JEOL) Solvent: Deuterated chloroform Measurement samples: Samples taken before and after hydrogenation of the polymer. Sample concentration: 50 mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0100] (Styrene blocking amount of hydrogenated conjugated diene polymers) A chain of eight or more styrene structural units was defined as a styrene block, and the amount of styrene blocks was determined as follows: Using deuterated chloroform as a solvent, the rubbery polymer was subjected to a 400 MHz reaction. 1 The 1H-NMR spectrum was measured. From the spectrum, the integral value ratio of each chemical shift range of (X) below was determined, and the amount of styrene block contained in the rubbery polymer was found. Styrene chain of 8 or more: 6.00 ≤ X < 6.68

[0101] (Ethylene structure content of hydrogenated conjugated diene polymers) 1 The ethylene structure content of hydrogenated conjugated diene polymers was measured using 1H-NMR. The conditions are described below. <Measurement conditions> Measuring instrument: JNM-LA400 (manufactured by JEOL) Solvent: Deuterated chloroform Measurement sample: Hydrogenated conjugated diene polymer Sample concentration: 50 mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0102] (Degradation rate of hydrogenated conjugated diene polymers) The denaturation rates of the hydrogenated conjugated diene polymers in the examples and comparative examples described later were measured by column adsorption GPC as follows. The measurement was performed by utilizing the property that conjugated diene polymers modified with nitrogen atom-containing functional groups adsorb onto a column. The amount of adsorption onto the silica column was determined by comparing the chromatograms obtained using a polystyrene column with the chromatograms obtained using a silica column for a sample solution containing the sample and a low molecular weight internal standard polystyrene, and the denaturation rate was then calculated. Specifically, these are as follows: <Preparation of sample solution>: 10 mg of the sample for measurement and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to prepare the sample solution. <GPC measurement conditions using polystyrene columns>: 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 columns used were: guard column: "TSKguardcolumn SuperH-H" (manufactured by Tosoh Corporation), and columns: "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" (manufactured by Tosoh Corporation). Chromatograms were obtained by measurement using an RI detector (Tosoh Corporation HLC8020) under conditions of a column oven temperature of 40°C and a THF flow rate of 0.6 mL / min. <GPC measurement conditions using silica-based columns>: Using the "HLC-8320GPC" column manufactured by Tosoh Corporation, 50 μL of the sample solution was injected into the instrument with THF as the eluent. A chromatogram was obtained using an RI detector under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were "Zorbax PSM-1000S," "PSM-300S," and "PSM-60S," with a "DIOL 4.6×12.5 mm 5 micron" column connected before them as a guard column. <Method for calculating the rate of degeneration>: The denaturation rate (%) was calculated using the following formula, with the total peak area of ​​the chromatogram using a polystyrene column set to 100, the peak area of ​​the sample being P1, and the peak area of ​​standard polystyrene being P2. The total peak area of ​​the chromatogram using a silica column was also set to 100, with the peak area of ​​the sample being P3 and the peak area of ​​standard polystyrene being P4. Degeneration rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100 (In the above formula, P1+P2=P3+P4=100)

[0103] [Method for evaluating characteristics] (Mooney viscosity (ML) of hydrogenated conjugated diene polymers) Mooney viscosity was measured using a Mooney viscometer (product 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 was measured after 4 minutes to determine the Mooney viscosity (ML). (1+4) ) was obtained.

[0104] (Cold flow resistance of hydrogenated conjugated diene polymers) A rectangular container with dimensions of 210 mm on the long side, 105 mm on the short side, and 200 mm in depth was filled with a sample heated to 60°C, and compressed with a cylinder at a pressure of 3.5 MPa for 10 seconds to obtain a rectangular molded body. Using the obtained molded body, the thickness (H72) after being left for 72 hours under a load of 5 kg at an ambient temperature of 25°C and 50% humidity was used to calculate the rate of change in thickness (%) using the following formula, and further, the thickness change index was calculated. Percentage change in thickness (%) = (H0 - H72) × 100 / H0 Thickness change index = (Percentage change in thickness of the standard hydrogenated conjugated diene polymer) ÷ (Percentage change in thickness of the hydrogenated conjugated diene polymer being evaluated) × 100 H0 indicates the thickness of the sample immediately after molding. A smaller rate of change in thickness and a smaller index of change in thickness indicate less cold flow of the sample during storage and superior handling. The index of thickness change of the hydrogenated conjugated diene polymers to be evaluated was assessed using the following indicators. (For the standard hydrogenated conjugated diene polymers, please refer to Table 1 below.) ◎: Thickness change index is 140 or higher ○: Thickness change index is 120 or more but less than 140 △: Thickness change index is between 80 and 120 ×: Thickness change index is less than 80

[0105] [Production of hydrogenated conjugated diene polymers] (Preparation of hydrogenated catalyst) In the examples and comparative examples described later, the hydrogenation catalyst used when preparing the hydrogenated conjugated diene polymers was prepared by the following method. In a nitrogen-purged reaction vessel, 1 L of dried and purified cyclohexane was charged, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added, and while stirring thoroughly, an n-hexane solution containing 200 mmol of trimethylaluminum was added and the reaction was carried out at room temperature for about 3 days to obtain a hydrogenated catalyst.

[0106] (Example 1: Production of hydrogenated conjugated diene polymer A1) In a nitrogen-purged autoclave reactor with a volume of 40 L, 22,000 g of cyclohexane, 30 mmol of tetrahydrofuran (THF), 7.0 mmol of 2,2-di(2-tetrahydrofuryl)propane, 450 g of styrene, and 2,550 g of 1,3-butadiene were charged. The temperature of the reactor contents was adjusted to 43°C, and then a cyclohexane solution containing 40.0 mmol of n-butyllithium was added to initiate polymerization, which was carried out under adiabatic conditions.

[0107] Two minutes after the reaction temperature reached its peak, 8.0 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacyloridine was added as a denaturing agent, and the polymer was allowed to react with the active sites for 20 minutes. Subsequently, 8.0 mmol of methanol was added to this polymer solution as a reaction termination agent to obtain the conjugated diene polymer solution before hydrogenation.

[0108] In the subsequent hydrogenation reaction step, a reactor with a capacity of 40 L, equipped with a rotary stirrer with a rotational speed of 114 rpm, had an L / D ratio (L: reactor height, D: reactor diameter) of 2.2, and had three nozzles each at the top and bottom (referred to as nozzles A, B, and C at the top, and nozzles D, E, and F at the bottom), and one additional nozzle (referred to as nozzle G) on the central side of the reactor. The reactor temperature was adjusted to 90°C, and then the conjugated diene polymer solution (polymer concentration 12% by mass) obtained above was supplied from nozzle A at the top of the reactor at a rate of 1.7 kg / h. Furthermore, the hydrogenated catalyst prepared as described above was added to the polymer solution at a concentration of 100 ppm on a titanium basis relative to the amount of charged monomer, and the solution was withdrawn from nozzle D at the bottom of the reactor while adjusting the liquid level in the reactor to 60%. At this time, the average residence time τ of the polymer was 70 minutes, and the H / D (H: liquid level, D: reactor diameter) was 1.3. Subsequently, hydrogen was instantaneously introduced into the reactor from nozzle E at the bottom of the reactor to a pressure of 0.6 MPa, and the supply was immediately stopped. Then, the polymer flowing out from the reactor's withdrawal nozzle D was sampled every 10 minutes, and the hydrogenation rate was measured. The obtained hydrogenation rates were plotted against the average residence time τ based on the impulse response method, and fitted using the following equation (2), resulting in an approximate value of 1.1 for the number of complete mixing tanks, N.

[0109]

number

[0110] Under the same reactor conditions as described above, hydrogen was continuously supplied to maintain a pressure of 0.6 MPa, and the hydrogenation reaction was carried out. Next, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added to the obtained hydrogenated conjugated diene polymer solution as antioxidants. Then, an aqueous solution (temperature: 80°C) adjusted to pH 8.5 (pH at 80°C, determined by the glass electrode method, the same applies hereafter) with ammonia as a pH adjuster was placed in a desolvation tank, and the above hydrogenated conjugated diene polymer solution was further added to the desolvation tank (200 parts by mass of aqueous solution per 100 parts by mass of polymer solution), and desolvation was carried out in the liquid phase of the desolvation tank (temperature: 95°C) by steam stripping (steam temperature: 190°C) for 2 hours. After that, the remaining water was dried in a dryer to obtain hydrogenated conjugated diene polymer A1. The analytical values ​​for hydrogenated conjugated diene polymer A1 are shown in Table 3 below.

[0111] (Comparative Example 1: Preparation of Hydrogenated Conjugated Diene Polymer A1') In a nitrogen-purged 40 L autoclave reactor, 22,000 g of cyclohexane, 30 mmol of tetrahydrofuran (THF), 7.0 mmol of 2,2-di(2-tetrahydrofuryl)propane, 450 g of styrene, and 2,550 g of 1,3-butadiene were charged. After adjusting the temperature of the reactor contents to 43°C, a cyclohexane solution containing 40.0 mmol of n-butyllithium was added to initiate polymerization, which was carried out under adiabatic conditions.

[0112] Two minutes after the reaction temperature reached its peak, 8.0 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacyloridine was added as a denaturing agent, and the reaction was allowed to proceed for 20 minutes at the active sites of the conjugated diene polymer. Subsequently, 8.0 mmol of methanol was added to this conjugated diene polymer solution as a reaction termination agent to obtain the conjugated diene polymer solution before hydrogenation.

[0113] In the subsequent hydrogenation reaction step, a reactor with a capacity of 40 L and an L / D ratio of 2.2 was used, equipped with a rotary stirrer with a rotational speed of 114 rpm. After adjusting the reactor temperature to 90°C, the entire amount of the conjugated diene polymer solution (polymer concentration 12% by mass) obtained above was packed into the reactor. Then, the hydrogenation catalyst prepared as described above was added to the conjugated diene polymer solution at a concentration of 100 ppm of titanium relative to the amount of monomer charged, and the hydrogenation reaction was carried out for 70 minutes while filling the reactor with hydrogen to a pressure of 0.6 MPa. Next, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added to the obtained polymer solution as antioxidants. Then, an aqueous solution (temperature: 80°C) was adjusted to pH 8.5 (pH at 80°C, determined by the glass electrode method, the same applies hereafter) with ammonia as a pH adjuster and placed in a desolvation tank. The hydrogenated conjugated diene polymer solution was then added to the desolvation tank (200 parts by mass of aqueous solution per 100 parts by mass of polymer solution), and desolvation was carried out in the liquid phase of the desolvation tank (temperature: 95°C) by steam stripping (steam temperature: 190°C) for 2 hours. After that, the remaining water was dried in a dryer to obtain the hydrogenated conjugated diene polymer A1'. Table 3 shows the analytical values ​​for the hydrogenated conjugated diene polymer A1'.

[0114] (Example 2: Production of hydrogenated conjugated diene polymer A2) In a nitrogen-purged autoclave reactor with a volume of 40 L, 22,000 g of cyclohexane, 30 mmol of tetrahydrofuran (THF), 7.0 mmol of 2,2-di(2-tetrahydrofuryl)propane, and 240 g of styrene were charged. After adjusting the temperature of the reactor contents to 43°C, a cyclohexane solution containing 40.0 mmol of n-butyllithium was added to start polymerization, and polymerization was carried out under adiabatic conditions for 10 minutes. Hydrogenated conjugated diene polymer A2 was obtained in the same manner as in Example 1, except that 210 g of styrene and 2550 g of 1,3-butadiene were added and polymerization was carried out under adiabatic conditions.

[0115] (Comparative Example 2: Preparation of Hydrogenated Conjugated Diene Polymer A2') In a nitrogen-purged autoclave reactor with a volume of 40 L, 22,000 g of cyclohexane, 30 mmol of tetrahydrofuran (THF), 7.0 mmol of 2,2-di(2-tetrahydrofuryl)propane, and 360 g of styrene were charged. After adjusting the temperature of the reactor contents to 43°C, a cyclohexane solution containing 40.0 mmol of n-butyllithium was added to start polymerization, and polymerization was carried out under adiabatic conditions for 10 minutes. Hydrogenated conjugated diene polymer A2' was obtained in the same manner as in Example 1, except that 90 g of styrene and 2550 g of 1,3-butadiene were added and polymerization was carried out under adiabatic conditions.

[0116] (Comparative Example 3: Preparation of Hydrogenated Conjugated Diene Polymer A3') Hydrogenated conjugated diene polymer A3' was obtained in the same manner as in Comparative Example 1, except that the reaction time for the hydrogenation step was set to 100 minutes.

[0117] (Comparative Example 4: Preparation of Hydrogenated Conjugated Diene Polymer A4') Hydrogenated conjugated diene polymer A4' was obtained in the same manner as in Example 1, except that 56 mmol of 2,2-di(2-tetrahydrofuryl)propane, 320 mmol of n-butyllithium, 64 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasiloridine, and 64 mmol of methanol were used.

[0118] (Comparative Example 5: Preparation of Hydrogenated Conjugated Diene Polymer A5') Hydrogenated conjugated diene polymer A5' was obtained in the same manner as in Example 1, except that the mixture consisted of 1.2 mmol of 2,2-di(2-tetrahydrofuryl)propane, 6.4 mmol of n-butyllithium, 1.3 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasiloridine, and 1.3 mmol of methanol.

[0119] (Example 3: Production of hydrogenated conjugated diene polymer A3) Hydrogenated conjugated diene polymer A3 was obtained in the same manner as in Example 1, except that 6.1 mmol of 2,2-di(2-tetrahydrofuryl)propane, 35 mmol of n-butyllithium, and 35 mmol of methanol were used, and 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasiloridine was not added.

[0120] (Comparative Example 6: Preparation of Hydrogenated Conjugated Diene Polymer A6') Hydrogenated conjugated diene polymer A6' was obtained in the same manner as in Comparative Example 1, except that 6.1 mmol of 2,2-di(2-tetrahydrofuryl)propane, 35 mmol of n-butyllithium, and 35 mmol of methanol were used, and 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacyloridine was not added.

[0121] (Example 4: Preparation of hydrogenated conjugated diene polymer A4) Hydrogenated conjugated diene polymer A4 was obtained in the same manner as in Example 1, except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 6.1 mmol, n-butyllithium was 35 mmol, 1,3-dimethyl-2-imidazolidinone was 28 mmol, and methanol was 7.0 mmol.

[0122] (Comparative Example 7: Preparation of Hydrogenated Conjugated Diene Polymer A7') Hydrogenated conjugated diene polymer A7' was obtained in the same manner as in Comparative Example 1, except that the mixture consisted of 6.1 mmol of 2,2-di(2-tetrahydrofuryl)propane, 35 mmol of n-butyllithium, 28 mmol of 1,3-dimethyl-2-imidazolidinone, and 7.0 mmol of methanol.

[0123] (Example 5: Production of hydrogenated conjugated diene polymer B1) Hydrogenated conjugated diene polymer B1 was obtained in the same manner as in Example 1, except that 4.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 120 g of styrene, and 2880 g of 1,3-butadiene were used.

[0124] (Comparative Example 8: Preparation of Hydrogenated Conjugated Diene Polymer B1') Hydrogenated conjugated diene polymer B1' was obtained in the same manner as in Comparative Example 1, except that 4.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 120 g of styrene, and 2880 g of 1,3-butadiene were used.

[0125] (Example 6: Preparation of hydrogenated conjugated diene polymer B2) Hydrogenated conjugated diene polymer B2 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0126] (Comparative Example 9: Preparation of Hydrogenated Conjugated Diene Polymer B2') Hydrogenated conjugated diene polymer B2' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0127] (Example 7: Production of hydrogenated conjugated diene polymer B3) Hydrogenated conjugated diene polymer B3 was obtained in the same manner as in Example 1, except that 19.5 mmol of 2,2-di(2-tetrahydrofuryl)propane, 780 g of styrene, and 2220 g of 1,3-butadiene were used.

[0128] (Comparative Example 10: Preparation of Hydrogenated Conjugated Diene Polymer B3') Polymer B3' was obtained in the same manner as in Comparative Example 1, except that 19.5 mmol of 2,2-di(2-tetrahydrofuryl)propane, 780 g of styrene, and 2220 g of 1,3-butadiene were used.

[0129] (Example 8: Preparation of hydrogenated conjugated diene polymer B4) Hydrogenated conjugated diene polymer B4 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 1200 g of styrene, and 1800 g of 1,3-butadiene were used.

[0130] (Comparative Example 11: Preparation of Hydrogenated Conjugated Diene Polymer B4') Hydrogenated conjugated diene polymer B4' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 1200 g of styrene, and 1800 g of 1,3-butadiene were used.

[0131] (Example 9: Production of hydrogenated conjugated diene polymer B5) Hydrogenated conjugated diene polymer B5 was obtained in the same manner as in Example 1, except that styrene was not added and 3000 g of 1,3-butadiene was used.

[0132] (Comparative Example 12: Preparation of Hydrogenated Conjugated Diene Polymer B5') Hydrogenated conjugated diene polymer B5' was obtained in the same manner as in Comparative Example 1, except that styrene was not added and 3000 g of 1,3-butadiene was used.

[0133] (Example 10: Production of hydrogenated conjugated diene polymer C1) Hydrogenated conjugated diene polymer C1 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0134] (Example 11: Production of hydrogenated conjugated diene polymer C2) Hydrogenated conjugated diene polymer C2 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the polymer supply rate in the hydrogenation reaction step was 1.5 kg / h.

[0135] (Example 12: Production of hydrogenated conjugated diene polymer C3) Hydrogenated conjugated diene polymer C3 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the polymer supply rate in the hydrogenation reaction step was 1.2 kg / h.

[0136] (Example 13: Preparation of hydrogenated conjugated diene polymer C4) Hydrogenated conjugated diene polymer C4 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the polymer supply rate in the hydrogenation reaction step was 2.7 kg / h.

[0137] (Example 14: Preparation of hydrogenated conjugated diene polymer C5) Hydrogenated conjugated diene polymer C5 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the polymer supply rate in the hydrogenation reaction step was 3.3 kg / h.

[0138] (Example 15: Production of hydrogenated conjugated diene polymer C6) Hydrogenated conjugated diene polymer C6 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the polymer supply rate in the hydrogenation reaction step was 5.8 kg / h.

[0139] (Comparative Example 13: Production of Hydrogenated Conjugated Diene Polymer C1') Hydrogenated conjugated diene polymer C1' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0140] (Comparative Example 14: Preparation of Hydrogenated Conjugated Diene Polymer C2') Hydrogenated conjugated diene polymer C2' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the hydrogenation reaction step was omitted.

[0141] (Comparative Example 15: Preparation of Hydrogenated Conjugated Diene Polymer C3') Hydrogenated conjugated diene polymer C3' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and the reaction time for the hydrogenation step was 35 minutes.

[0142] (Comparative Example 16: Preparation of Hydrogenated Conjugated Diene Polymer C4') Hydrogenated conjugated diene polymer C4' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, 2760 g of 1,3-butadiene, and a reaction time of 20 minutes for the hydrogenation step were used.

[0143] (Example 16: Preparation of hydrogenated conjugated diene polymer D1) Hydrogenated conjugated diene polymer D1 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0144] (Example 17: Preparation of hydrogenated conjugated diene polymer D2) Three hydrogenated conjugated diene polymers with different hydrogenation rates were obtained using the same method as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the reaction times for the hydrogenation step were set to 81 minutes, 70 minutes, and 55 minutes, with 1 / 3 of the contents being drawn out at each time. Subsequently, the hydrogenated conjugated diene polymers obtained were mixed in equal amounts to obtain hydrogenated conjugated diene polymer D2. At this time, the value of the hydrogenation rate distribution HWD was 1.01.

[0145] (Example 18: Preparation of hydrogenated conjugated diene polymer D3) Five hydrogenated conjugated diene polymers with different hydrogenation rates were obtained using the same method as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the reaction time for the hydrogenation step was varied in five levels: 105 minutes, 81 minutes, 70 minutes, 55 minutes, and 42 minutes (1 / 5 of the contents were extracted at each time). Subsequently, the five hydrogenated conjugated diene polymers obtained were mixed so that they contained equal amounts to obtain hydrogenated conjugated diene polymer D3. At this time, the value of the hydrogenation rate distribution HWD was 1.04.

[0146] (Example 19: Preparation of hydrogenated conjugated diene polymer D4) Hydrogenated conjugated diene polymer D4 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the polymer solution was supplied from nozzle F at the bottom of the reactor and withdrawn from nozzle B at the top of the reactor during the hydrogenation step. At this time, the value of the number of complete mixing tanks N, measured by the impulse response method, was 2.3.

[0147] (Example 20: Preparation of hydrogenated conjugated diene polymer D5) Hydrogenated conjugated diene polymer D5 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the rotation speed in the hydrogenation step was 70 rpm. At this time, the value of the number of complete mixing tanks N, measured by the impulse response method, was 1.3.

[0148] (Example 21: Preparation of hydrogenated conjugated diene polymer D6) Hydrogenated conjugated diene polymer D6 was obtained in the same manner as in Example 19, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and 20% of the polymer solution supplied from nozzle A at the top of the reactor during the hydrogenation step was supplied from nozzle G on the central side of the reactor, thereby changing the number of complete mixing tanks N to 1.2. At this time, the value of the number of complete mixing tanks N, determined by the impulse response method, was 1.2.

[0149] (Example 22: Preparation of hydrogenated conjugated diene polymer D7) Hydrogenated conjugated diene polymer D7 was obtained in the same manner as in Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used, and the hydrogenation step was performed at a rotation speed of 20 rpm, a polymer supply rate of 2.3 kg / h, and a reactor liquid level of 80%. At this time, the H / D ratio (H: liquid level, D: reactor diameter) was 1.8, and the value of the number of complete mixing tanks N, determined by the impulse response method, was 2.2.

[0150] (Comparative Example 17: Preparation of Hydrogenated Conjugated Diene Polymer D1') Hydrogenated conjugated diene polymer D1' was obtained in the same manner as in Comparative Example 1, except that 11.6 mmol of 2,2-di(2-tetrahydrofuryl)propane, 240 g of styrene, and 2760 g of 1,3-butadiene were used.

[0151] [Evaluation of rubber compositions containing hydrogenated conjugated diene polymers A1-D1'] A rubber composition was obtained by mixing each component according to the formulation shown in Table 2 below and the method described below. Note that the amount of each compounding agent added in Table 2 is shown as parts by mass relative to 100 parts by mass of the rubber component excluding the rubber softener, i.e., the hydrogenated conjugated diene polymer.

[0152] (Mixing method) Using a sealed kneader (capacity 0.5L) equipped with a temperature control device, the first stage of kneading involved mixing all materials except sulfur and vulcanization accelerators under conditions of a 65% filling rate and a rotor rotation speed of 50-90 rpm. During this process, the temperature of the sealed mixer was controlled, and the resulting mixture was obtained at a discharge temperature of 150-160°C. 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 as well, the discharge temperature of the mixture was adjusted to 150-160°C by controlling the temperature of the mixer. After cooling, in the third stage of kneading, the mixture was kneaded in an open roll oven set to 70°C with a vulcanization accelerator and sulfur to obtain an unvulcanized rubber composition. Subsequently, the mixture was molded and vulcanized using a vulcanization press at 160°C for a predetermined vulcanization time to obtain the vulcanized rubber composition. The vulcanization time was set to the 90% vulcanization time of the unvulcanized rubber composition plus 5 minutes. The rubber composition after vulcanization was evaluated by the following method.

[0153] [Evaluation items and test methods] The obtained unvulcanized rubber composition and vulcanized rubber composition were evaluated as follows. The results are shown in Tables 3 to 6 below.

[0154] ((1) Processability (Mooney viscosity (compound ML))) Using the unvulcanized rubber composition obtained above as a sample, a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used to measure the viscosity after preheating to 130°C for 1 minute in accordance with ISO 289, followed by rotating the rotor at 2 revolutions per minute for 4 minutes. The measurement results of the unvulcanized rubber composition of hydrogenated conjugated diene polymers, which served as the baseline for comparison, were indexed with a value of 100, and the following indicators were used for evaluation. The standard hydrogenated conjugated diene polymers are shown in Table 1 below. ◎: Index less than 80 ○: Index is 80 or higher but less than 90 △: Index is between 90 and 110 ×: Index is 110 or higher

[0155] ((2) Tensile properties) The vulcanized rubber composition obtained above was used as a sample, and its tensile properties were measured in accordance with the tensile test method of JIS K6251. The measurement results of the hydrogenated conjugated diene polymer vulcanized rubber composition, which served as the baseline for comparison, were indexed to 100, and the following indicators were used for evaluation. The standard hydrogenated conjugated diene polymers are shown in Table 1 below. <Tensile Strength (TB)> ◎: Index is 120 or higher ○: Index is 110 or higher but less than 120 △: Index is between 90 and 110 ×: Index less than 90 <Tensile elongation (EB)> ◎: Index is 120 or higher ○: Index is 110 or higher but less than 120 △: Index is between 90 and 110 ×: Index less than 90

[0156] ((3) Ozone resistance) From the vulcanized rubber composition obtained above, strip-shaped samples (6 cm long x 1 cm wide x 2.0 mm thick) were punched out and placed in an ozone bath (40°C, 50 pphm) and left to stand for 96 hours in a state of 20% elongation. After that, the strip-shaped samples (vulcanized rubber sheets) were observed and the number of cracks of 1 mm or longer on the surface was counted. The number of cracks in the vulcanized rubber sheet of the hydrogenated conjugated diene polymer, which served as a reference for comparison, was then indexed to 100 and judged according to the following indicators. The standard hydrogenated conjugated diene polymers are shown in Table 1 below. ◎: Index is less than 60, or no cracks have occurred in the vulcanized rubber sheet. ○: Index is 60 or higher but less than 80 △: Index is between 80 and 120 ×: Index is 120 or higher, or the vulcanized rubber sheet has ruptured.

[0157] (4) Fuel efficiency Using a viscoelasticity tester "ARES" manufactured by Rheometrics Scientific, the tanδ measured in torsion mode at 50°C, frequency of 10 Hz, and strain of 3% was used as an indicator of fuel efficiency. The measurement results of the hydrogenated conjugated diene polymer vulcanized rubber composition, which served as the baseline for comparison, were then indexed to 100, and the following indicators were used for evaluation. The standard hydrogenated conjugated diene polymers are shown in Table 1 below. ◎: Index less than 80 ○: Index is 80 or higher but less than 90 △: Index is between 90 and 110 ×: Index is 110 or higher

[0158] In Table 2 below, the names of the products used for each ingredient are as follows: • Hydrogenated conjugated diene polymers: A1~D1' • Natural rubber: RSS No. 3 (Producer: UNIMAC RUBBER CO., LTD. (Thailand), Supplier: Marubeni Techno Rubber) • Carbon black: Seast SO (FEF) manufactured by Tokai Carbon Co., Ltd. (Specific surface area of ​​nitrogen adsorption: 42 m²) 2 / g) • Softener: Process oil PF30 (SRAE oil) manufactured by JXTG Energy Corporation. • Zinc oxide: Zinc oxide manufactured by Sakai Chemical Industry Co., Ltd. • Stearic acid: Lunac S-90V manufactured by Kao Corporation • Wax: Sunnock manufactured by Ouchi Shinko Chemical Co., Ltd. • Anti-aging agent: Nocrack 6C manufactured by Ouchi Shinko Chemical Co., Ltd. • Sulfur: Powdered sulfur Sulfax 200S manufactured by Tsurumi Chemical Industries Co., Ltd. • Vulcanization accelerator: TBBS Sunceller NS-G (N-tert-butylbenzothiazole-2-sulfenamide) manufactured by Sanshin Chemical Co., Ltd.

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] [Table 5]

[0164]

Table 6

[0165] From Tables 3 to 6, it was confirmed that the polymers of Examples 1 to 22 were excellent in processability and cold flow resistance when compared with the "reference hydrogenated conjugated diene polymer" described in Table 1, and were excellent in ozone resistance and breaking physical properties when made into rubber compositions.

[0166] As described above, according to the present invention, it has become clear that it is possible to provide a hydrogenated conjugated diene polymer that ensures the processability and cold flow resistance of the hydrogenated conjugated diene polymer and the rubber composition using the same, and is excellent in ozone resistance, breaking physical properties, and low hysteresis loss when made into a rubber composition.

[0167] This application is based on Japanese Patent Application (Japanese Patent Application No. 2022-178955) filed with the Japan Patent Office on November 8, 2022, the content of which is incorporated herein by reference.

Industrial Applicability

[0168] The present invention has industrial applicability as materials for tire treads, casings such as sidewalls, packings, gaskets, sealing materials, vibration-proof rubber, vibration-isolation rubber, vibration-damping materials, conveyor belts, shoe outsoles and midsoles, automotive weather strips, glass runs, trunk lids, railway vehicle members, aircraft members, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary products, industrial and various-purpose hoses, battery cases, adhesives, wire coatings, window frame rubbers, rubber rollers for OA equipment and textiles, key pads, keyboard covers, underwater glasses, swimming caps, container bags, marine-related parts, indoor floor materials, artificial muscle materials, and various industrial products.

Claims

1. A hydrogenated conjugated diene polymer that satisfies the following conditions (i) to (iii). <Condition (i)> A random polymer containing conjugated diene monomer units and possibly aromatic vinyl monomer units, The content of aromatic vinyl monomer blocks is less than 10% by mass of the hydrogenated conjugated diene polymer. <Condition (ii)> Weight-average molecular weight is 10 × 10 ４ The above 200 x 10 ４ The following applies: <Condition (iii)> The molecular weight distribution of ozone decomposition products is between 2.1 and 6.

0.

2. The hydrogenated conjugated diene polymer according to claim 1, wherein the hydrogenation rate is 97 mol% or less.

3. The hydrogenated conjugated diene polymer according to claim 1, wherein the hydrogenation rate is 50 mol% or more.

4. The hydrogenated conjugated diene polymer according to claim 1, wherein the ethylene structure is 1% by mass or more.

5. A hydrogenated conjugated diene polymer according to claim 1, comprising aromatic vinyl monomer units.

6. A method for producing a hydrogenated conjugated diene polymer according to any one of claims 1 to 5, Weight-average molecular weight is 10 × 10 ４ The above 200 x 10 ４ The following describes a polymerization step to obtain a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass, A hydrogenation process to obtain multiple types of hydrogenated conjugated diene polymers with different hydrogenation rates, A mixing step is performed in which the above-mentioned multiple types of hydrogenated conjugated diene polymers are mixed so that the hydrogenation rate distribution HWD represented by the following formula (1) is 1.005 or higher. A method for producing a hydrogenated conjugated diene polymer having the following characteristics. [Math 1] (In formula (1), n ​​represents the total number of hydrogenated conjugated diene polymers having different hydrogenation rates, and w ｉ Among them, a specific hydrogenation rate H ｉ This represents the mass fraction of the hydrogenated conjugated diene polymer containing [specific compound] within the total hydrogenated conjugated diene polymers.

7. A method for producing a hydrogenated conjugated diene polymer according to any one of claims 1 to 5, Weight-average molecular weight is 10 × 10 ４ The above 200 x 10 ４ The following describes a polymerization step to obtain a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass, A hydrogenation step is performed by adding hydrogen to the aforementioned conjugated diene polymer. It has, The hydrogenation process is a continuous process, and the number of complete mixing tanks N, when the residence time distribution in the reactor is fitted using the impulse response method with a complete mixing tank model, is set to 1.0 to 2.

5. A method for producing hydrogenated conjugated diene polymers.

8. In the reactor of the hydrogenation step, hydrogen and the conjugated diene polymer are supplied from opposing directions, or hydrogen and / or the conjugated diene polymer are supplied from multiple locations. A method for producing a hydrogenated conjugated diene polymer according to claim 7.

9. In the continuous process described above, a stirred-tank reactor is used, the conjugated diene polymer and the hydrogenation catalyst are supplied from the top of the stirred-tank reactor, and hydrogen is supplied from the bottom of the stirred-tank reactor while stirring is performed. The hydrogenated conjugated diene polymer is extruded from the bottom of the tank of the aforementioned stirred-tank type reactor. A method for producing a hydrogenated conjugated diene polymer according to claim 7.

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