Hydrogenated conjugated diene polymer and method for producing hydrogenated conjugated diene polymer

Abstract

The present invention provides a hydrogenated conjugated diene polymer which satisfies the following conditions (i)-(iii). Lt; condition (i) gt; a hydrogenated conjugated diene polymer which is a random polymer containing a conjugated diene monomer unit and optionally containing an aromatic vinyl monomer unit, and which is characterized in that the aromatic vinyl monomer block is less than 10% by mass of the hydrogenated conjugated diene polymer. Lt; condition (ii) gt; and a weight average molecular weight of 10 * 104 or more and 200 * 104 or less. Lt; condition (iii) gt; the molecular weight distribution of the ozone decomposition product is from 2.1 to 6.0 (inclusive).

Description

Technical Field

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

[0002] Conventionally, rubber products such as tires are required to have improved ozone resistance, durability such as breaking strength, and low hysteresis loss. For example, Patent Documents 1 and 2 propose technologies regarding rubber compositions, which are rubber compositions blended with hydrogenated conjugated diene polymers and have improved ozone resistance.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2017 / 014282

[0006] Patent Document 2: Japanese Patent No. 6845679 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, when the hydrogenation process of the conjugated diene polymer is carried out in a batch mode as described in Patent Documents 1 and 2, if the hydrogenation rate is increased in order to improve the ozone resistance, the viscosity of the obtained hydrogenated conjugated diene polymer will increase significantly due to the entanglement of the polymer chains, and there is a problem that the processability of the hydrogenated conjugated diene polymer and the rubber composition will be significantly deteriorated.

[0009] When the molecular weight of the conjugated diene polymer is reduced in order to improve the above-mentioned processability, the cold flow resistance is deteriorated and the breaking properties are reduced.

[0010] Furthermore, when the hydrogenation rate is reduced, although the processability is improved, the ozone resistance, fracture properties, and cold flow resistance are deteriorated.

[0011] On the other hand, although the cold flow resistance (fluidity) and breaking properties of the hydrogenated conjugated diene polymer and the rubber composition can be improved by introducing a small amount of an aromatic vinyl monomer block into the conjugated diene polymer, this has the problem of deteriorating the low hysteresis loss property.

[0012] That is, the above-mentioned hydrogenated conjugated diene polymers and rubber compositions proposed in the past have the problem that it is difficult to achieve excellent ozone resistance, fracture properties and low hysteresis loss properties while ensuring good processability and cold flow resistance.

[0013] Therefore, in view of the above-mentioned problems of the prior art, an object of the present invention is to provide a hydrogenated conjugated diene polymer which can ensure good processability and cold flow resistance and can achieve excellent processability, ozone resistance, fracture properties and low hysteresis loss when prepared into a rubber composition.

[0014] Means for solving problems

[0015] The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art and have found that a hydrogenated conjugated diene polymer having a specific aromatic vinyl block content, weight average molecular weight, and molecular weight distribution of ozone decomposition products can solve the above-mentioned problems, thereby completing the present invention.

[0016] That is, the present invention is as follows. [1]

[0018] A hydrogenated conjugated diene polymer that satisfies the following conditions (i) to (iii).

[0019] <Condition (i)>

[0020] It is a random polymer containing a conjugated diene monomer unit and may contain an aromatic vinyl monomer unit.

[0021] The content of the aromatic vinyl monomer block is less than 10% by mass of the hydrogenated conjugated diene polymer.

[0022] <Condition (ii)>

[0023] The weight average molecular weight is 10×10 4 Above 200×10 4 the following.

[0024] <Condition (iii)>

[0025] The molecular weight distribution of the ozone decomposition product is 2.1 or more and 6.0 or less. [2]

[0027] The hydrogenated conjugated diene polymer as described in the above [1], wherein the hydrogenation rate is 97 mol% or less. [3]

[0029] The hydrogenated conjugated diene polymer as described in [1] or [2] above, wherein the hydrogenation rate is 50 mol% or more. [4]

[0031] The hydrogenated conjugated diene polymer according to any one of [1] to [3] above, wherein the ethylene structure accounts for 1% by mass or more. [5]

[0033] The hydrogenated conjugated diene polymer according to any one of the above [1] to [4], comprising an aromatic vinyl monomer unit. [6]

[0035] A method for producing a hydrogenated conjugated diene polymer, which is the method for producing a hydrogenated conjugated diene polymer described in any one of [1] to [5] above, wherein the method comprises the following steps:

[0036] The polymerization step yields a weight average molecular weight of 10×10 4 Above 200×10 4 The following, a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass;

[0037] A hydrogenation step to obtain a plurality of hydrogenated conjugated diene polymers having different hydrogenation rates; and

[0038] In the mixing step, the plurality of hydrogenated conjugated diene polymers are mixed so that the hydrogenation rate distribution HWD represented by the following formula (1) is 1.005 or more.

[0039] [Number 1]

[0040]

[0041] In formula (1), n ​​represents the total number of hydrogenated conjugated diene polymers having different hydrogenation rates, and w i Indicates that there is a specific hydrogenation rate H i The mass fraction of the hydrogenated conjugated diene polymer in all hydrogenated conjugated diene polymers. [7]

[0043] A method for producing a hydrogenated conjugated diene polymer, which is the method for producing a hydrogenated conjugated diene polymer described in any one of [1] to [5] above, wherein the method comprises the following steps:

[0044] The polymerization step yields a weight average molecular weight of 10×10 4 Above 200×10 4 The following conjugated diene polymers having an aromatic vinyl monomer block content of less than 10% by mass; and

[0045] A hydrogenation step of hydrogenating the conjugated diene polymer.

[0046] The hydrogenation step is made into a continuous process, and the number N of completely mixed tank trains when fitting the residence time distribution in the reactor by the impulse response method in the completely mixed tank train model is set to 1.0 to 2.5. [8]

[0048] The method for producing a hydrogenated conjugated diene polymer as described in [7] above, wherein in the reactor of the hydrogenation step, hydrogen and the conjugated diene polymer are supplied from opposite directions, or hydrogen and / or the conjugated diene polymer are supplied from a plurality of positions. [9]

[0050] The method for producing a hydrogenated conjugated diene polymer as described in [7] or [8] above, wherein:

[0051] In the continuous process, a stirred tank reactor is used, the conjugated diene polymer and the hydrogenation catalyst are supplied from the upper part of the stirred tank reactor, and hydrogen is supplied from the bottom of the stirred tank reactor while stirring.

[0052] The hydrogenated conjugated diene polymer was extruded from the bottom of the stirred tank reactor.

[0053] Effects of the Invention

[0054] According to the present invention, there can be provided a hydrogenated conjugated diene polymer having good processability and cold flow resistance and excellent processability, ozone resistance, breaking properties and low hysteresis loss when made into a rubber composition. DETAILED DESCRIPTION

[0055] A specific embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described in detail below.

[0056] It should be noted 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 implemented by appropriately modifying the present invention within the scope of the gist thereof.

[0057] [Hydrogenated conjugated diene polymer]

[0058] The hydrogenated conjugated diene polymer of the present embodiment satisfies the following conditions (i) to (iii).

[0059] <Condition (i)>

[0060] It is a random polymer containing a conjugated diene monomer unit and may contain an aromatic vinyl monomer unit.

[0061] The content of the aromatic vinyl monomer block is less than 10% by mass of the hydrogenated conjugated diene polymer.

[0062] <Condition (ii)>

[0063] The weight average molecular weight is 10×10 4 Above 200×10 4 the following.

[0064] <Condition (iii)>

[0065] The molecular weight distribution of the ozone decomposition product is 2.1 or more and 6.0 or less.

[0066] According to the above-mentioned structure, the processability and cold flow resistance are good, and as described below, when the hydrogenated conjugated diene polymer of this embodiment is appropriately combined with other polymers, filler components, plasticizer components, cross-linking agent components, etc. to prepare a rubber composition, the processability, ozone resistance, fracture properties and low hysteresis loss are excellent.

[0067] The hydrogenated conjugated diene polymer of the present embodiment has a structural unit based on a conjugated diene compound (hereinafter also referred to as a "conjugated diene monomer unit"), and a structure based on a structure obtained by partially hydrogenating a conjugated diene as a monomer or a structural unit based on ethylene (hereinafter also referred to as an "ethylene structure"). The hydrogenated conjugated diene polymer of the present embodiment preferably includes a structural unit based on an aromatic vinyl compound (aromatic vinyl monomer unit).

[0068] The ethylene structure is formed by hydrogenating a conjugated diene monomer unit to convert a part of the double bond portion into an ethylene structure, or by copolymerizing a conjugated diene compound and ethylene.

[0069] From the viewpoint of production cost, the hydrogenated conjugated diene polymer of the present embodiment is preferably obtained by subjecting the conjugated diene polymer to a hydrogenation reaction. By controlling the hydrogenation rate to be high, the content of the ethylene structure can be increased.

[0070] It should be noted that, in the hydrogenated conjugated diene polymer of the present embodiment, the structure formed by hydrogenating the polymer chain at both ends of the main chain of the conjugated diene monomer unit (for example, 1,4-bond of a polymer with 1,3-butadiene as a monomer) is regarded as an ethylene structure, and the structure formed by hydrogenating other forms (for example, 1,2-vinyl bond of a polymer with 1,3-butadiene as a monomer) is not included in the ethylene structure.

[0071] As the conjugated diene compound for forming the conjugated diene monomer unit, for example, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, etc. can be cited but not limited to. They can be used alone or in combination of two or more. Among these, from the practical point of view of the ease of obtaining the monomer, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

[0072] (Condition (i) Content of aromatic vinyl monomer units)

[0073] The hydrogenated conjugated diene polymer of the present embodiment may contain an aromatic vinyl monomer unit. From the perspective of the breaking strength of the rubber composition, the content of the aromatic vinyl monomer unit 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.

[0074] In terms of low hysteresis loss properties of the rubber composition, the content of the aromatic vinyl monomer unit 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 the hydrogenated conjugated diene polymer of the present embodiment.

[0075] It should be noted that the content of the aromatic vinyl monomer unit can be measured by the method described in the examples below, and the content of the aromatic vinyl monomer can be controlled within the above-mentioned numerical range by adjusting the addition timing, addition amount and polymerization time of the aromatic vinyl compound in the polymerization step of the conjugated diene polymer.

[0076] As the aromatic vinyl compound forming the aromatic vinyl monomer unit, for example, styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, etc. can be cited but not limited to. They can be used alone or in combination of two or more. Among these, styrene is particularly preferred from the viewpoint of practical aspects such as the ease of obtaining the monomer.

[0077] In the hydrogenated conjugated diene polymer of the present embodiment, from the perspective of low hysteresis loss of the rubber composition, the content of the aromatic vinyl monomer block (the long chain ratio of the structural unit based on the aromatic vinyl compound) is 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 the present embodiment. The low hysteresis loss of the rubber composition has the following advantages: when used as tire rubber, it contributes to the fuel efficiency of the tire, and in industrial products such as cushion rubber, the stress change during repeated deformation is also small.

[0078] The content of the aromatic vinyl monomer block in the hydrogenated conjugated diene polymer of the present embodiment can be controlled within the above numerical range by adjusting the amount or timing of addition of the aromatic vinyl compound in the polymerization step, the amount of the randomizer added, and the like.

[0079] From the aspect of reducing the hysteresis loss of the rubber composition, the hydrogenated conjugated diene polymer of the present embodiment is a random polymer. It should be noted that in this specification, "random polymer" means that the long chain ratio of the aromatic vinyl monomer unit is less than 10% by mass relative to the total mass of the hydrogenated conjugated diene polymer. Here, the long chain ratio refers to the ratio of a chain (long chain) formed by more than 8 consecutive structural units relative to the entire structural unit. It should be noted that in the case of a polymer using two or more monomer units, the two or more monomer units can be uniformly distributed in the above-mentioned polymer, or can be distributed in a tapered, stepped, convex, or concave shape.

[0080] Here, the long chain ratio of the aromatic vinyl monomer unit is obtained as follows: the hydrogenated conjugated diene polymer of the present embodiment is measured using deuterated chloroform as a solvent. 1 In the H-NMR spectrum, the ratio of the integral value of the chemical shift S range of (a) to the total integral value of each chemical shift S range of (a) to (c) is calculated to obtain the long chain ratio. For example, when the aromatic vinyl monomer is styrene, the ratio of the integral value of the range of (a) to the total integral value of each range of (a) to (c) is calculated, and the value is multiplied by 2.5 to calculate the ratio of styrene. In this way, the long chain ratio of the aromatic vinyl monomer unit can be understood.

[0081] (a) Chain of aromatic vinyl monomer units of 8 or more: 6.00≦S<6.68

[0082] (b) Chains 2 to 7 of aromatic vinyl monomer units: 6.68≦S<6.89

[0083] (c) Single chain of aromatic vinyl monomer unit: 6.89≦S≦8.00

[0084] As described above, from the viewpoint of low hysteresis loss of the rubber composition, the hydrogenated conjugated diene polymer of the present embodiment is a random polymer.

[0085] The hydrogenated conjugated diene polymer of the present embodiment may be modified or unmodified, but is preferably a modified random polymer from the viewpoint of reinforcement by the filler component of the rubber composition and wear resistance.

[0086] The modification method is as described below, and examples of the modified hydrogenated conjugated diene polymer include those obtained by introducing a functional group into the polymerization termination terminal of the polymer using a modifying agent.

[0087] (Amount of ethylene structure and hydrogenation rate)

[0088] In the case where the hydrogenated conjugated diene polymer of the present embodiment is obtained by hydrogenating the conjugated diene polymer, the ethylene structure formed by hydrogenation of the 1,4-bond preferably has 1% by mass or more, more preferably 2% by mass or more, and further preferably 5% by mass or more, from the perspective of ozone resistance and tensile strength of the rubber composition containing the hydrogenated conjugated diene polymer of the present embodiment. In addition, although the upper limit of the ethylene structure depends on the content of the aromatic vinyl monomer unit before hydrogenation and the amount of 1,2-vinyl bonds, it is preferably 95% by mass or less, and more preferably 90% by mass or less from the perspective of processability.

[0089] Regarding the amount of ethylene structure in the hydrogenated conjugated diene polymer of the present embodiment, for example, in the case of a polymer composed of styrene and 1,3-butadiene as monomers, it can be controlled by adjusting the ratio of styrene to 1,3-butadiene, the ratio of 1,4-bonds to 1,2-vinyl bonds in the butadiene part, and the hydrogenation rate.

[0090] Examples of a method for increasing the amount of ethylene structures include a method of reducing the styrene ratio and increasing the butadiene ratio, a method of increasing the 1,4-bond ratio of the butadiene part, and a method of increasing the hydrogenation rate.

[0091] On the contrary, by increasing the styrene ratio and decreasing the butadiene ratio, the 1,4-bond ratio of the butadiene part and the hydrogenation rate can be reduced, thereby reducing the amount of the ethylene structure.

[0092] For example, in the case of a polymer formed from 1,3-butadiene as a monomer, 1,4-bonds and 1,2-vinyl bonds are generated by polymerization; however, when a polymer containing both is hydrogenated, the 1,2-vinyl bond tends to be hydrogenated first by rapid hydrogenation reaction. Therefore, in order to achieve "having 1% by mass or more of ethylene structure", it is preferred to form more than 1% by mass of 1,4-bonds by polymerization, and then perform hydrogenation reaction until most of the 1,2-vinyl bonds are consumed and 1,4-bonds are hydrogenated by 1% by mass or more, thereby forming more than 1% by mass of ethylene structure.

[0093] Specifically, the numerical value of the hydrogenation rate is preferably higher than the numerical value of the ratio of 1,2-vinyl bonds in the ratio of conjugated diene monomer units by 1% or more, more preferably higher than 2%, but as described below, in the case of a distribution of the hydrogenation rate, even if the numerical value of the hydrogenation rate is smaller than the numerical value of the 1,2-vinyl bond amount, sometimes 1% or more of 1,4-bonds are hydrogenated. The hydrogenation rate (the ratio of hydrogenation for the conjugated diene portion) is preferably a hydrogenation rate in which 1,4-bonds are hydrogenated in a manner having an ethylene structure of more than 1% by mass, although it depends on the amount of 1,2-vinyl bonds before hydrogenation, the hydrogenation rate is preferably more than 50 mol%, more preferably more than 60 mol%, and further preferably more than 70 mol%. In addition, from the perspective of giving full play to the effect of the hydrogenation rate distribution described later, the hydrogenation rate of the hydrogenated conjugated diene polymer of the present embodiment is preferably less than 97 mol%, more preferably less than 93 mol%, more preferably less than 90 mol%, further more preferably less than 88 mol%, and most preferably less than 85 mol%.

[0094] The hydrogenation rate can be determined according to 1 The hydrogen conversion rate is calculated from the spectrum reduction rate of the unsaturated bond part of the spectrum obtained by H-NMR measurement, and corresponds to the average hydrogenation rate when the hydrogen conversion rate has a distribution as described below.

[0095] (Weight average molecular weight)

[0096] From the viewpoint of the tensile strength of the rubber composition, the weight average molecular weight (Mw) of the hydrogenated conjugated diene polymer of the present embodiment is 10×10 4 More than 15×10 4 More preferably, 20×10 4 In addition, from the perspective of processability of the hydrogenated conjugated diene polymer and the rubber composition of the present embodiment, the weight average molecular weight of the hydrogenated conjugated diene polymer is 200×10 4 Below, preferably 100×10 4 Below, more preferably 70×10 4 the following.

[0097] (Molecular weight distribution)

[0098] From the perspective of the processability of the hydrogenated conjugated diene polymer and the rubber composition, the molecular weight distribution (Mw / Mn) of the hydrogenated conjugated diene polymer of the present embodiment is preferably 1.1 or more, more preferably 1.2 or more, and further preferably 1.3 or more. In addition, from the perspective of the low hysteresis loss of the rubber composition, the molecular weight distribution of the hydrogenated conjugated diene polymer is preferably 4.0 or less, more preferably 3.5 or less, and further preferably 3.0 or less.

[0099] In addition, the weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by the method described in the examples mentioned later.

[0100] (Molecular weight distribution of ozone decomposition products (hydrogenation rate distribution))

[0101] From the viewpoint of achieving a high balance among processability, cold flow resistance, ozone resistance, and tensile strength of the rubber composition, the hydrogenation rate of the hydrogenated conjugated diene polymer of the present embodiment preferably has a distribution.

[0102] In the case where the hydrogenation rate distribution of the hydrogenated conjugated diene polymer is narrow, that is, the hydrogenation rate is single or the frequency distribution of the hydrogenation rate shows a sharp peak, as a method for improving the ozone resistance and tensile strength of the rubber composition, for example, a method for improving the hydrogenation rate as shown in International Publication No. 2014 / 133097 can be considered, but if the hydrogenation rate increases, the Mooney viscosity of the obtained hydrogenated conjugated diene polymer will become too high, and the processability tends to deteriorate. In order to ensure good processability, it is possible to consider reducing the molecular weight, but if the molecular weight is reduced, it will cause a decrease in tensile strength when the rubber composition is made, so there is a tendency to be difficult to take these physical properties into account.

[0103] On the other hand, when the distribution of the hydrogenation rate of the hydrogenated conjugated diene polymer has a wide range, that is, when the frequency distribution of the hydrogenation rate shows a broad peak, since a low hydrogenation rate component excellent in processability and cross-linking properties coexists with a high hydrogenation rate component excellent in ozone resistance and tensile properties when prepared as a rubber composition, these physical properties can be highly balanced.

[0104] In addition, a hydrogenated conjugated diene polymer having such a wide distribution of hydrogenation rates has a characteristic that, when compared at the same average hydrogenation rate, the rubber composition has a better ozone resistance than a hydrogenated conjugated diene polymer having a narrow distribution of hydrogenation rates. This is considered to be because, since a component having a large number of units derived from an ethylene structure in a molecular chain, such as a high hydrogenation rate component, has a lower surface free energy than a low hydrogenation rate component, when the hydrogenated conjugated diene polymer is made into a rubber composition, it tends to segregate to the surface of the rubber composition, and when it is made into a sulfide, it acts like the protective film of the sulfide, having an effect of preventing ozone from entering the sulfide and preventing the sulfide from deteriorating.

[0105] The hydrogenation rate distribution of the hydrogenated conjugated diene polymer can be indirectly evaluated by the following method. That is, the double bonds in the hydrogenated conjugated diene polymer are decomposed by ozone using a method known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)), and the molecular weight distribution of the decomposed product is analyzed by GPC (gel permeation chromatography). The hydrogenation rate distribution of the hydrogenated conjugated diene polymer can be evaluated by this method.

[0106] Specifically, as the hydrogenated conjugated diene polymer of the present embodiment, assuming that it is a random copolymer of butadiene and styrene, if all double bonds in the conjugated diene polymer are hydrogenated, there are no double bonds that will be cut by ozone decomposition, so the decomposition product is only one type of polymer that has not been cut. On the other hand, if the conjugated diene polymer is not hydrogenated, the part polymerized by 1,4-bonds of butadiene will be completely cut, so according to the length of adjacent 1,4-bonds, there will be one or more decomposition products containing styrene, one or more decomposition products containing styrene and 1,2-bonds, and one or more decomposition products containing only 1,2-bonds. In this case, although the molecular weight distribution of the decomposition product has a certain degree of breadth depending on the frequency of 1,4-bonds or the randomness of styrene, since there are many low molecular weight decomposition products as a whole, the breadth is about 1.8 and will not increase to more than 2.1. If the hydrogenation rate distribution of the hydrogenated conjugated diene polymer is broad, both decomposition products close to the uncut polymer and finely cut decomposition products are included, so the molecular chain length distribution of the ozone decomposition products also becomes broad, and the molecular weight distribution of the ozone decomposition products becomes broad.

[0107] When the hydrogenation rate distribution of the hydrogenated conjugated diene polymer of the present embodiment is evaluated by the molecular weight distribution of the above-mentioned ozone decomposition product, the molecular weight distribution of the ozone decomposition product is 2.1 or more, preferably 2.2 or more, more preferably 2.3 or more, further preferably 2.45 or more, and further more preferably 2.50 or more, from the viewpoint of highly balancing the processability and cold flow resistance of the hydrogenated conjugated diene polymer and the rubber composition of the present embodiment, and the ozone resistance and tensile strength of the rubber composition.

[0108] The molecular weight distribution of the ozone decomposition product being 2.1 or more means that the hydrogenation rate distribution of the hydrogenated conjugated diene polymer of the present embodiment has a certain degree of breadth, which can balance the processability, cold flow resistance, ozone resistance and tensile strength of the hydrogenated conjugated diene polymer and the rubber composition of the present embodiment.

[0109] From the viewpoint of fully exerting the ozone resistance and tensile strength of the rubber composition, the molecular weight distribution of the ozone decomposition product is 6.0 or less, preferably 5.7 or less, more preferably 5.5 or less, further preferably 5.0 or less, and further more preferably 4.7 or less.

[0110] By setting the molecular weight distribution of the ozone decomposition product to 6.0 or less, a component with an extremely low hydrogenation rate is less likely to be included, and the ozone resistance and tensile strength of the rubber composition can be fully expressed.

[0111] The molecular weight distribution of the hydrogenated conjugated diene polymer has little effect on the molecular weight distribution of the above-mentioned ozone decomposition product. This is because the aromatic vinyl monomer block of the hydrogenated conjugated diene polymer of this embodiment is less than 10% by mass, and the aromatic vinyl monomer block that will not be decomposed by ozone decomposition does not exist or is relatively small; and because the molecular chain length after ozone decomposition is not affected by the molecular chain length before ozone decomposition.

[0112] The molecular weight distribution of the ozone decomposed product is controlled within the above numerical range by adjusting the distribution of 1,2-bonds and 1,4-bonds and the distribution of hydrogenation rate of the hydrogenated conjugated diene polymer of the present embodiment, for example. Specifically, there can be cited: a method of imparting distribution to 1,2-bonds and 1,4-bonds; a method of imparting distribution to the hydrogenation rate in the hydrogenated conjugated diene polymer of the present embodiment as described below; and the like.

[0113] In the hydrogenated conjugated diene polymer of the present embodiment, from the viewpoint of achieving a high balance between the processability, cold flow resistance, ozone resistance and tensile strength of the hydrogenated conjugated diene polymer of the present embodiment and the rubber composition, the area ratio S up to the peak top molecular weight of the ozone decomposition product represented by the following formula (I) measured by GPC (gel permeation chromatography) after decomposition by the above-mentioned ozone decomposition method is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less.

[0114] Area ratio S of ozone decomposition products up to the peak molecular weight = A / B×100···(I)

[0115] A: Peak area from molecular weight 200 to peak top molecular weight of ozone decomposition product by GPC

[0116] B: The total area of ​​the peak with a molecular weight of 200 or more in GPC of ozone decomposition products

[0117] [Method for producing hydrogenated conjugated diene polymer]

[0118] The hydrogenated conjugated diene polymer of the present embodiment can be produced, for example, by the following method: a method having 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 a method having a polymerization step of copolymerizing a conjugated diene compound, ethylene and an aromatic vinyl compound.

[0119] In order to form the above-mentioned ethylene structure, a hydrogenation step may be performed, or ethylene may be copolymerized in the polymerization step. In addition, when ethylene is copolymerized in the polymerization step, a hydrogenation step may be performed.

[0120] Furthermore, the modification step described later may be performed as necessary.

[0121] In the polymerization process, the polymerized product has a weight average molecular weight of 10×10 4 Above 200×10 4 The following is a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass.

[0122] (Polymerization process)

[0123] The polymerization step can be implemented by a solution polymerization method. The monomer concentration in the solution is preferably 5% by mass or more, more preferably 10% by mass or more. By making the monomer concentration in the solution 5% by mass or more, there is a tendency that the amount of the conjugated diene polymer obtained is increased and the cost is reduced. In addition, the monomer concentration in the solution is preferably 50% by mass or less, more preferably 30% by mass or less. By making the monomer concentration in the solution 50% by mass or less, there is a tendency that the solution viscosity is further reduced, the stirring efficiency is improved, and the polymerization is easy to carry out.

[0124] When anionic polymerization is performed in the polymerization step, the polymerization initiator is not particularly limited, but an organic lithium compound is preferably used.

[0125] As the organolithium compound, for example, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, the reaction product of diisopropenylbenzene and butyllithium, etc. are mentioned but not limited thereto. Among them, an organolithium compound having an alkyl group having 2 to 20 carbon atoms is preferred, and n-butyllithium or sec-butyllithium is preferred from the aspects of availability, safety, etc.

[0126] When coordination polymerization is performed in the polymerization step, it is preferable to use a polymerization catalyst composition described in JP-A-2020-45500 as a polymerization initiator.

[0127] There is no particular limitation on the method for producing a conjugated diene polymer by anionic polymerization or coordination polymerization using a polymerization initiator, and a conventionally known method can be used. Specifically, in an organic solvent inert to the reaction, such as a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, butyl lithium is used as a polymerization initiator, and styrene, 1,3-butadiene, ethylene, etc. are polymerized in the presence of a specified randomizer as required, thereby obtaining the target conjugated diene polymer.

[0128] The hydrocarbon solvent is preferably a hydrocarbon solvent having 3 to 8 carbon atoms. Examples thereof include, but are not limited to, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propylene, 1-butene, isobutylene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, and the like.

[0129] These solvents may be used alone or in combination of two or more.

[0130] The randomizer is a compound that has the effect of controlling the microstructure of the conjugated diene portion in the conjugated diene polymer (e.g., increasing the 1,2-vinyl bond in butadiene and the 3,4-bond in isoprene), or controlling the composition distribution of the monomer units in the conjugated diene polymer (e.g., randomizing the styrene unit and the butadiene unit in the styrene-butadiene copolymer).

[0131] The randomizer is not particularly limited, and any randomizer may be selected from known compounds that have been conventionally used as randomizers.

[0132] The randomizer may include, but is not limited to, ethers such as dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(2-tetrahydrofuranyl)propane, triethylamine, pyridine, N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, 1,2-dipiperidylethane, and tertiary amines. Potassium salts such as potassium tert-amylate and potassium tert-butoxide, and sodium salts such as sodium tert-amylate may also be used.

[0133] These randomizers may be used alone or in combination of two or more.

[0134] In addition, the amount of the randomizer is preferably 0.01 molar equivalent or more, more preferably 0.05 molar equivalent or more, relative to each 1 mole of polymerization initiator. By making the amount of the randomizer more than 0.01 molar equivalent per 1 mole of polymerization initiator, there is a tendency to more easily perform randomization. In addition, the amount of the randomizer is preferably 1000 molar equivalent or less, more preferably 500 molar equivalent or less, relative to each 1 mole of polymerization initiator. By making the amount of the randomizer less than 1000 molar equivalent per 1 mole of polymerization initiator, there is a tendency to reduce the change in the reaction rate of the monomer and suppress the situation where randomization becomes difficult.

[0135] The reaction temperature in the polymerization step is not particularly limited as long as the reaction can proceed appropriately, but is usually preferably 10°C to 130°C, more preferably 25°C to 110°C.

[0136] (Modification process)

[0137] Furthermore, in the method for producing a hydrogenated conjugated diene polymer according to the present embodiment, a modification step of modifying the obtained conjugated diene polymer may be included after the above-mentioned polymerization step.

[0138] When the modification step is performed, it is preferred to add a conjugated diene compound at the end of the polymerization step so that the polymerization terminal becomes a conjugated diene monomer unit. This tends to allow the reaction using the modifying agent to proceed more appropriately.

[0139] The modification step is, for example, a step of reacting the active terminal of the conjugated diene polymer obtained in the polymerization step with a compound having a functional group that interacts with silicon oxide and / or carbon black.

[0140] Through the modification step, a functional group that interacts with silicon oxide and / or carbon black can be introduced into the polymerization termination terminal of the conjugated diene polymer to obtain a conjugated diene polymer with a modified polymerization termination terminal. It should be noted that the above-mentioned terminal refers to the part existing at the end of the molecular chain, excluding the structure derived from the monomer having a carbon-carbon double bond.

[0141] In the modification step, the active end of the conjugated diene polymer obtained by the polymerization step is reacted with a compound having a functional group that interacts with silicon oxide and / or carbon black. In addition, by using a polymerization initiator having a functional group that interacts with silicon oxide and / or carbon black in the molecule for polymerization, a functional group can be introduced into the starting end of the conjugated diene polymer. Functional groups can also be introduced into both the starting end and the terminating end as required.

[0142] The conjugated diene polymer used in the modification reaction (hereinafter also referred to as "terminal modification reaction") only needs to have an active terminal, and the polymerization initiation terminal may be unmodified or modified. In addition, as a compound having the above-mentioned functional group, there is no particular limitation as long as it has a functional group that interacts with silicon oxide and / or carbon black and can react with the polymerization active terminal of the conjugated diene polymer. As a specific modification reaction using these conjugated diene polymers and compounds having functional groups, a method of introducing functional groups into the conjugated diene polymer using a terminal modifier containing a tin atom or a nitrogen atom is preferred, and a method of introducing functional groups into the conjugated diene polymer using a terminal modifier containing a nitrogen atom is more preferred.

[0143] As the terminal modifier containing nitrogen atoms, from the viewpoint of polymerization productivity and high modification rate, for example, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing nitrogen groups, vinyl compounds containing nitrogen groups, epoxy compounds containing nitrogen groups, alkoxysilane compounds containing nitrogen groups, cyclic urea compounds, etc. are preferred. In particular, from the viewpoint of polymerization productivity, high modification rate, and reinforcing properties based on fillers, alkoxysilane compounds containing nitrogen groups and cyclic urea compounds are more preferred.

[0144] These modifiers may be used alone or in combination of two or more.

[0145] Examples of the nitrogen group-containing alkoxysilane compound include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacycloheptane, 2,2 -Dimethoxy-1-(3-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 1-aza-2-silacyclopentane, 2-ethoxy-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, tetra[3- [2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine, 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-propylenediamine.

[0146] Examples of the cyclic urea compound include, but are not limited to, 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, 1-methyl-3-butyl-2-imidazolidinone, 1,3-dihydro-1,3-dimethyl-2H-imidazolidinone, 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.

[0147] The terminal modification reaction of the conjugated diene polymer can be carried out in the form of a solution reaction, for example. The solution reaction can be carried out using a solution containing unreacted monomers after the polymerization reaction in the polymerization step is terminated, or the conjugated diene polymer contained in the solution can be separated and dissolved in a suitable solvent such as cyclohexane. In addition, the terminal modification reaction can be carried out using any of the intermittent and continuous methods, or any of their combinations. At this time, the method for adding the terminal modifier is not particularly limited, and can be any of the methods of uniform addition, batch addition, and continuous addition.

[0148] The amount of the terminal modifier used in the terminal modification reaction can be appropriately set according to the type of the terminal modifier used in the reaction, and is preferably 0.1 molar equivalent or more, more preferably 0.3 molar equivalent or more relative to the metal atom participating in the polymerization reaction possessed by the polymerization initiator. By making it 0.1 molar equivalent or more, the modification reaction can be fully carried out, and it can interact appropriately with filler components such as silicon oxide and carbon black, and the dispersibility of the filler components can be appropriately improved.

[0149] The temperature of the terminal modification reaction is usually the same as the temperature of the above-mentioned polymerization reaction, 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. On the other hand, the lower the temperature of the modification reaction, the less likely the polymerization active terminal is to be deactivated. The reaction time of 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.

[0150] (Termination of polymerization process)

[0151] The polymerization step in the method for producing the hydrogenated conjugated diene polymer can be terminated by adding a reaction terminator commonly used in the field. Such a reaction terminator may be, for example, 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 non-polar solvents such as hexane and cyclohexane.

[0152] The amount of the reaction terminator added is usually sufficient in an amount equal to or twice the molar amount of the anionic polymerization initiator.

[0153] (Hydrogenation process)

[0154] When the hydrogenated conjugated diene polymer of the present embodiment is produced by hydrogenating the conjugated diene polymer, the hydrogenation method and reaction conditions are not particularly limited, and the hydrogenation can be carried out by a known method and under known conditions.

[0155] The hydrogenation reaction can be generally carried out at 20 to 150° C. and 0.1 to 10 MPa of hydrogen pressure in the presence of a hydrogenation catalyst. It should be noted that the hydrogenation rate of the hydrogenated conjugated diene polymer of this embodiment can be controlled by adjusting the amount and type of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, the reaction time, etc.

[0156] As the hydrogenation reaction process, any of a batch type and a continuous type, or a combination thereof may be used. In order to make the molecular weight distribution of the ozone decomposed product of the hydrogenated conjugated diene polymer of the present embodiment 2.1 to 6.0, it is necessary to give a distribution to the hydrogenation rate.

[0157] Examples of methods for imparting a distribution to the hydrogenation rate distribution include: a method of obtaining a plurality of hydrogenated conjugated diene polymers having different hydrogenation rates and further mixing these plurality of hydrogenated conjugated diene copolymers; a method of making the hydrogenation step a continuous process and controlling the residence time distribution in the reactor for carrying out the hydrogenation step; and the like.

[0158] When a plurality of hydrogenated conjugated diene polymers having different hydrogenation rates are obtained and mixed, the hydrogenation rate distribution HWD of the obtained hydrogenated conjugated diene polymers can be represented by the following formula (1).

[0159] [Number 2]

[0160]

[0161] In the above formula (1), n ​​represents the total number of hydrogenated conjugated diene polymers having different hydrogenation rates, and w represents i Indicates that there is a specific hydrogenation rate H iThe mass fraction of the hydrogenated conjugated diene polymer in all hydrogenated conjugated diene polymers.

[0162] Although the hydrogenation rate distribution HWD of the obtained hydrogenated conjugated diene polymer and the molecular weight distribution of the ozone decomposition product also depend on the microstructure, the base hydrogenation rate, and the mixing ratio of the plurality of hydrogenated conjugated diene polymers, for example, when a conjugated diene polymer having a styrene content of 8% by mass and a 1,2-vinyl bond content of 40% is hydrogenated, and hydrogenated conjugated diene polymers having hydrogenation rates changed by 20% on the higher hydrogenation side and the lower hydrogenation side relative to the base hydrogenation rate are mixed in equal amounts, the hydrogenation rate distribution HWD is 1.02 to 1.1, and the molecular weight distribution of the ozone decomposition product is about 2.2 to 4.5. In addition, when the same conjugated diene polymer as above is hydrogenated and the hydrogenated conjugated diene polymers having hydrogenation rates obtained by changing the hydrogenation rates by 10% on the high hydrogenation side and the low hydrogenation side relative to the base hydrogenation rate are mixed in the same amount, the hydrogenation rate distribution HWD is 1.005 to 1.02 and the molecular weight distribution of the ozone decomposition product is about 2.1 to 3.5. By adopting a method of broadening the hydrogenation rate distribution, the molecular weight distribution of the ozone decomposition product of the hydrogenated conjugated diene polymer can be controlled to 2.1 to 6.0. By making the above hydrogenation rate distribution HWD 1.005 or more and controlling the molecular weight distribution of the ozone decomposition product of the hydrogenated conjugated diene polymer to a numerical range of 2.1 to 6.0, there is a tendency to obtain a hydrogenated conjugated diene polymer with a high balance of cold flow resistance, ozone resistance and tensile strength.

[0163] When the hydrogenation step is carried out by a continuous process, the flow path through which the conjugated diene polymer passes can be changed by adjusting the solution viscosity, the amount of solution in the reactor, the stirring conditions, or by changing the number of supply ports for the conjugated diene polymer to the continuous hydrogenation reactor, thereby adjusting the reaction time distribution (residence time distribution), thereby enabling the distribution width of the hydrogenation rate of the generated hydrogenated conjugated diene polymer to be controlled.

[0164] As an index of the reaction time distribution (residence time distribution), there is a value N when the degree of mixing is represented by a complete mixing tank row model in which N complete mixing tanks of equal volume are connected in series. It is preferable to reduce the value N to approach complete mixing. Specifically, the value N can be reduced by reducing the solution viscosity, increasing the stirring speed, and reducing the ratio of the height (H) of the liquid surface to the reactor diameter (D), that is, the value of H / D, thereby approaching complete mixing.

[0165] More specifically, when the hydrogenation step is carried out by a continuous process, by setting the number N of complete mixing tank trains when fitting the residence time distribution in the reactor by the impulse response method in the complete mixing tank train model to 1.0 to 2.5, the distribution width of the hydrogenation rate of the generated hydrogenated conjugated diene polymer can be widened, and the molecular weight distribution of the ozone decomposition product of the hydrogenated conjugated diene polymer can be controlled within a numerical range of 2.1 to 6.0, thereby obtaining a hydrogenated conjugated diene polymer with a high balance of cold flow resistance, ozone resistance and tensile strength.

[0166] In addition to the above-mentioned method, examples of methods for adjusting the reaction time distribution and widening the distribution width of the hydrogenation rate include methods (1) and (2).

[0167] Method (1): A method in which hydrogen and a conjugated diene polymer are supplied from opposite directions in a reactor for performing a hydrogenation step.

[0168] Method (2): A method of supplying hydrogen and / or a conjugated diene polymer from a plurality of positions.

[0169] In the case of the method (1) above, for example, the following method can be cited as a more preferred method for broadening the reaction time distribution and thus broadening the hydrogenation rate distribution, wherein a conjugated diene polymer solution and a hydrogenation catalyst are supplied from the upper part of the tank of the above-mentioned stirred tank type reactor, and stirring is performed while hydrogen is continuously supplied from the bottom of the tank of the stirred tank type reactor, and extruded from the bottom of the tank of the stirred tank type reactor by the continuous supply.

[0170] In the case of the method (2) above, for example, the following method can be cited as a preferred method, wherein in a continuous reaction process of hydrogenation to broaden the reaction time distribution, a plurality of supply ports for supplying a conjugated diene polymer to a reactor are provided, 80% of the total amount of the polymer is continuously supplied from the upper part of the reactor, 20% of the total amount is continuously supplied from the middle part of the reactor, and the total amount of the polymer after the hydrogenation reaction is continuously taken out from the lower part of the reactor.

[0171] In the case of the above methods (1) and (2), the N value of the above-mentioned complete mixing tank train model is about 1.0 to 1.8, although it depends on the L / D (L: height of the reactor, D: diameter of the reactor) of the reactor in which the hydrogenation reaction is carried out, the shape and rotation speed of the stirring blade, and the viscosity of the solution. The molecular weight distribution of the ozonolysis product of the obtained hydrogenated conjugated diene polymer is about 2.3 to 6.0, although it depends on the microstructure, the basic hydrogenation rate, etc.

[0172] In the continuous process of the above-mentioned hydrogenation step, the following method can be adopted: using a stirred tank reactor, the conjugated diene polymer solution, the homogeneous hydrogenation catalyst, and hydrogen are continuously supplied to the bottom of the stirred tank reactor while being stirred, thereby filling the inside of the stirred tank reactor, and the hydrogenated conjugated diene polymer is extruded from the upper part of the stirred tank reactor by the continuous supply of these polymer solution, hydrogenation catalyst and hydrogen.

[0173] Specific methods for the stirring conditions that broaden the reaction time distribution of the hydrogenation reaction include: a method of using a stirring tank reactor and a stirring machine to vigorously mix as a back-flow mixed reactor, preferably a method of using a complete mixing reactor, etc. According to this method, the number N can be reduced when a continuous reaction process of hydrogenation is represented by a complete mixing tank row, and the reaction time distribution can be expanded to obtain a hydrogenated conjugated diene polymer with a wide hydrogenation rate distribution.

[0174] As the fitting for calculating the number N of complete mixing tank arrays, for example, a known method such as an impulse response method or a step response method described in Chemical Engineering Handbook can be used.

[0175] As a hydrogenation catalyst, a compound containing any element of the metals of Groups 4 to 11 of the periodic table can generally be used. For example, a compound containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, or Pt atoms can be used as a hydrogenation catalyst. As more specific hydrogenation catalysts, there can be cited: metallocene compounds of Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, or Re; supported heterogeneous catalysts in which metals such as Pd, Ni, Pt, Rh, or Ru are supported on carriers such as carbon, silicon oxide, aluminum oxide, or diatomaceous earth; homogeneous Ziegler-type catalysts in which organic salts or acetylacetonates of metal elements such as Ni and Co are combined with reducing agents such as organic aluminum; organic metal compounds or complexes of Ru, Rh, or the like; fullerenes and carbon nanotubes that absorb hydrogen, or the like.

[0176] Among these, metallocene compounds containing any one of Ti, Zr, Hf, Co and Ni are preferred from the viewpoint that the hydrogenation reaction can proceed in a homogeneous phase in an inert organic solvent, and metallocene compounds containing any one of Ti, Zr and Hf are more preferred.

[0177] The hydrogenation catalyst may be used alone or in combination of two or more.

[0178] A preferred method for obtaining a hydrogenated conjugated diene polymer is to carry out solution polymerization, directly use the obtained polymer solution for modification treatment, and then provide it to a hydrogenation step as needed. In addition, since the hydrogenation reaction usually increases the viscosity of the solution, a step of diluting the solution with a solvent to reduce the viscosity of the solution in advance may be added before the hydrogenation step, depending on the process used.

[0179] (Desolventization process)

[0180] The hydrogenated conjugated diene polymer is obtained by removing the solvent from the polymer solution obtained above and isolating the polymer.

[0181] Examples of the method for isolating the hydrogenated conjugated diene polymer include a known desolvation method such as steam stripping, and a method of performing a drying operation such as heat treatment using a dehydrating extruder, a drying extruder, or a conveyor.

[0182] [Rubber composition]

[0183] The hydrogenated conjugated diene polymer of the present embodiment can be combined with other polymers, filler components, plasticizer components, crosslinking agent components, etc. to form a rubber composition having desired properties.

[0184] Examples of 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 alone or in combination of two or more.

[0185] The filler component is mixed in the rubber composition for the purpose of rubber reinforcement, and examples thereof include, but are not limited to, white fillers (inorganic fillers) such as silicon oxide, calcium carbonate, mica, aluminum hydroxide, magnesium oxide, magnesium hydroxide, clay, talc, aluminum oxide, titanium oxide, mica, and carbon black. These can be used alone or in combination of two or more. Silicon oxide and carbon black are particularly preferred.

[0186] From the aspect 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, relative to 100 parts by mass of the rubber component containing the hydrogenated conjugated diene polymer of the present embodiment and other polymers. In addition, when silicon oxide is used as the filler, from the aspect of processability and low hysteresis loss, the content of silicon oxide is preferably 120 parts by mass or less, more preferably 100 parts by mass or less.

[0187] The silicon oxide is not particularly limited, and examples thereof include dry process silicon oxide (anhydrous silicon oxide) and wet process silicon oxide (hydrous silicon oxide). Wet process silicon oxide is preferred because it contains a large number of silanol groups.

[0188] The nitrogen adsorption specific surface area (N2SA) of silicon oxide is preferably 60 m2 from the perspective of the wear resistance of the rubber composition. 2 / g or more, more preferably 120m 2 / g or more, preferably 300 m / g from the perspective of low fuel consumption of the rubber composition 2 / g or less, more preferably 200m 2 In addition, the nitrogen adsorption specific surface area of ​​silicon oxide is a value measured by the BET method in accordance with ASTM D3037-81.

[0189] Examples of carbon black include, but are not limited to, furnace blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black; thermal blacks such as FT and MT; channel blacks such as EPC, MPC, and CC; graphite, etc. These materials may be used alone or in combination of two or more.

[0190] The nitrogen adsorption specific surface area (N2SA) of carbon black is usually 5 to 200 m 2 / g, preferably 30 m / g from the viewpoint of the wear resistance of the rubber composition 2 / g or more, more preferably 50m 2 / g or more, and preferably 150m / g from the viewpoint of low fuel consumption of the rubber composition. 2 / g or less, more preferably 120m 2 The nitrogen adsorption specific surface area of ​​carbon black is measured in accordance with ASTM D4820-93.

[0191] The dibutyl phthalate (DBP) absorption of carbon black is usually 5 to 300 mL / 100 g, preferably with a lower limit of 80 mL / 100 g or more and an upper limit of 180 mL / 100 g or less. The DBP absorption value of carbon black is measured in accordance with ASTM D2414-93.

[0192] Silicon oxide is preferably used in combination with a silane coupling agent.

[0193] As the silane coupling agent, conventionally known substances can be used. Examples thereof 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, bis(3-trimethoxysilylethyl)tetrasulfide, Sulfide-based silane coupling agents such as 3-(4-(4-methylsilyl)propyl) disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropylmethacrylate monosulfide; 3-mercaptopropyltrimethoxysilane, 3-mercapto Propyl triethoxysilane, 2-mercaptoethyl trimethoxysilane, 2-mercaptoethyl triethoxysilane and other mercapto compounds; vinyl triethoxysilane, vinyl trimethoxysilane and other vinyl silane coupling agents; 3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane, 3-(2-aminoethyl) aminopropyl triethoxysilane, 3-(2-aminoethyl) aminopropyl trimethoxysilane and other amino silane coupling agents; γ-glycidoxypropyl triethyl Silane coupling agents include 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane and the like.

[0194] It should be noted that the silane coupling agent may be used alone or in combination of two or more. In particular, from the perspective of the coupling effect, processability, and cost of the silane coupling agent, a sulfide-based silane coupling agent is preferred, and bis(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide are more preferred.

[0195] From the perspective 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, more preferably 5 parts by mass or more, relative to 100 parts by mass of silicon oxide. In addition, from the perspective of processability and cost of the rubber composition, the content of the silane coupling agent is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, relative to 100 parts by mass of silicon oxide.

[0196] Examples of the plasticizer component include, but are not limited to, extender oils, resins other than the above-mentioned other polymers, antioxidants, waxes, stearic acid, vulcanization accelerators, etc. These may be used alone or in combination of two or more.

[0197] Examples of the extender oil include, but are not limited to, aromatic mineral oils (viscosity gravity constant (VGC value) 0.900 to 1.049), cycloparaffinic mineral oils (VGC value 0.850 to 0.899), and paraffinic mineral oils (VGC value 0.790 to 0.849).

[0198] The polycyclic aromatic content of the extender oil is preferably less than 3% by mass, more preferably less than 1% by mass. The polycyclic aromatic content of the extender oil can be measured according to the British Petroleum Institute 346 / 92 method. In addition, the aromatic compound content (CA) of the extender oil is preferably 20% by mass or more. The extender oil can be used alone or in combination of two or more.

[0199] From the perspective of Mooney viscosity, the content of the extender oil is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the rubber component. In addition, from the perspective of low hysteresis loss and hardness of the rubber composition, the content of the extender oil is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, relative to 100 parts by mass of the rubber component.

[0200] Examples of the resin 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.

[0201] These resins may be used alone or in combination of two or more, and are particularly preferably coumarone indene resins, phenolic resins (particularly terpene phenolic resins), α-methylstyrene and / or copolymers of styrene, and more preferably copolymers of α-methylstyrene and styrene.

[0202] From the perspective of wet grip performance of the rubber composition, the content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of the rubber component. In addition, from the perspective of low hysteresis loss properties of the rubber composition, the content of the resin is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, relative to 100 parts by mass of the rubber component.

[0203] Examples of the antioxidant include, but are not limited to, naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine antioxidants such as N-phenyl-N'-isopropyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and N,N'-di-2-naphthyl-p-phenylenediamine; quinoline antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol, triphenol and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane; and the like.

[0204] These components may be used alone 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.

[0205] The content of the antioxidant is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, based on 100 parts by mass of the rubber component.

[0206] Examples of the wax include, but are not limited to, petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant wax and animal wax; and synthetic waxes such as polymers of ethylene, propylene, and the like.

[0207] These waxes may be used alone or in combination of two or more. Among them, petroleum waxes are preferred, and paraffin wax is more preferred.

[0208] The content of the wax is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, based on 100 parts by mass of the rubber component.

[0209] As stearic acid, conventionally known substances can be used, and examples thereof include, but are not limited to, products of NOF Corporation, NOF Corporation, Kao Corporation, Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. These can be used alone or in combination of two or more.

[0210] The content of stearic acid is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, based on 100 parts by mass of the rubber component.

[0211] Examples of the vulcanization accelerator include, but are not limited to, thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, dibenzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazolyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide.

[0212] These components can be used alone or in combination of two or more. In particular, for the reason of more appropriately obtaining the effect of the present embodiment, a sulfenamide-based vulcanization accelerator is preferred, and N-cyclohexyl-2-benzothiazole sulfenamide is more preferred. In addition, a guanidine-based vulcanization accelerator is also preferably used in combination.

[0213] The content of the vulcanization accelerator is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, based on 100 parts by mass of the rubber component.

[0214] As a crosslinking agent component, it can be appropriately selected according to the purpose, and can include but is not limited to, for example, sulfur-based crosslinking agents, organic peroxide-based crosslinking agents, inorganic crosslinking agents, polyamine crosslinking agents, resin crosslinking agents, sulfur-containing compound-based crosslinking agents, oxime-nitrosoamine-based crosslinking agents, etc. They can be used alone or in combination of two or more. In particular, for the reason of more appropriately obtaining the effect of the present embodiment, sulfur-based crosslinking agents are preferred, and sulfur is more preferred. Regarding the content of the crosslinking agent in the rubber composition of the present embodiment, it is preferably 0.1 mass parts or more and 20 mass parts or less relative to 100 mass parts of the rubber component. It is preferably 0.1 mass parts or more, more preferably 0.5 mass parts or more, and more preferably 1.5 mass parts or more. In addition, it is preferably 20 mass parts or less, more preferably 5 mass parts or less, and more preferably 3 mass parts or less. Thus, the effect of the present embodiment can be more appropriately obtained.

[0215] A vulcanization accelerator may be used in combination with the rubber composition of the present embodiment.

[0216] Examples of the vulcanization accelerator include guanidine-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, sulfenamide-based, thiourea-based, thiuram-based, dithiocarbamate-based, and xanthate-based compounds.

[0217] Furthermore, the rubber composition of the present embodiment may contain various additives such as other softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants in addition to the above-mentioned various components.

[0218] As other softeners, known softeners can be used. As other fillers, for example, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate can be cited. As the above-mentioned heat stabilizer, antistatic agent, weathering stabilizer, anti-aging agent, colorant, and lubricant, known materials can be used respectively.

[0219] (Method for producing rubber composition)

[0220] The rubber composition containing the hydrogenated conjugated diene polymer of the present embodiment can be produced by a general method, for example, by kneading the components using a Banbury mixer, a kneader, an open roll mill, etc., followed by vulcanization.

[0221] Example

[0222] The present embodiment will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

[0223] Various physical properties in Examples and Comparative Examples were measured by the methods shown below, and were evaluated by the methods described later.

[0224] [Physical property measurement method]

[0225] (Amount of bonded styrene in conjugated diene polymer)

[0226] 100 mg of the sample before hydrogenation was dissolved in chloroform to 100 mL to prepare a measurement sample, and the amount of bonded styrene (mass %) relative to 100 mass % of the conjugated diene polymer as a sample was measured from the absorption of the ultraviolet absorption wavelength (near 254 nm) by the phenyl group of styrene.

[0227] As a measuring apparatus, a spectrophotometer “UV-2450” manufactured by Shimadzu Corporation was used.

[0228] (1,2-vinyl bond content of the butadiene portion of the conjugated diene polymer)

[0229] 50 mg of the sample before hydrogenation was dissolved in 10 mL of carbon disulfide to prepare a measurement sample.

[0230] Use a solution dish at 600-1000cm -1The infrared spectrum was measured in a range of , and the microstructure of the butadiene part, that is, the amount of 1,2-vinyl bonds (mol%) was determined according to the calculation formula of the Hampton method (RR Hampton, Analytical Chemistry 21, 923 (1949)) based on the absorbance at a specified wave number. As a measuring device, a Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation was used.

[0231] (Weight Average Molecular Weight (Mw) and Molecular Weight Distribution of Hydrogenated Conjugated Diene Polymer and Ozone Decomposition Product)

[0232] The chromatogram was measured using a GPC measuring apparatus having three connected columns filled with polystyrene gel, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the hydrogenated conjugated diene polymer and the ozone decomposition product were determined based on a calibration curve using standard polystyrene.

[0233] In addition, the molecular weight distribution (Mw / Mn) of the ozone decomposition product of the hydrogenated conjugated diene polymer is targeted at the range of 200 or more in terms of molecular weight in terms of polystyrene.

[0234] Specific measurement conditions are as follows.

[0235] 20 μL of the following measurement solution was injected into the GPC measurement device and the measurement was performed.

[0236] <Measurement Conditions>

[0237] Eluent: Tetrahydrofuran (THF) with 5 mmol / L triethylamine added

[0238] Guard column: Trade name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation

[0239] Separation column: A column in which "TSKgel SuperH5000", "TSKgel SuperH6000" and "TSKgel SuperH7000" manufactured by Tosoh Corporation are connected in sequence.

[0240] Oven temperature: 40℃

[0241] Flow rate: 0.6mL / min

[0242] Detector: RI detector (trade name "HLC8020" manufactured by Tosoh Corporation)

[0243] Measurement solution: 10 mg of the sample for measurement dissolved in 20 mL of THF

[0244] <Method for producing an ozone decomposed product of a hydrogenated conjugated diene polymer>

[0245] 100 mg of hydrogenated conjugated diene polymer was dissolved in 100 mL of dichloromethane, and the obtained sample solution was cooled at -30°C, while oxygen with an ozone (O3) concentration of 2% adjusted by an ozone generator was passed through the sample solution at 150 mL / min, and the gas coming out of the sample solution was passed through a detection liquid (a solution formed by adding 6 drops of 3% starch aqueous solution to 75 mL of 3% potassium iodide aqueous solution). One minute after the detection liquid changed color to yellow, the inflow of oxygen was stopped to obtain a sample solution of ozonide.

[0246] The obtained sample solution of the ozonide was cooled at -30°C under a nitrogen atmosphere and added dropwise at a rate of 6 mL / min to 50 mL of diethyl ether mixed with 0.5 g of lithium aluminum hydride, and then the sample solution was refluxed at 50°C for 15 minutes for reduction reaction. Next, 3 mL of pure water was added dropwise to the sample solution at a rate of 3 mL / min while cooling at -30°C for hydrolysis, and 3 g of potassium carbonate was further added for salting out and filtering, and the solvent of the obtained filtrate was removed using an evaporator to obtain an ozonolysis product of a hydrogenated conjugated diene polymer.

[0247] (Area ratio S of the hydrogenated conjugated diene polymer ozone decomposition product up to the peak molecular weight)

[0248] The area ratio S of the ozone decomposition product up to the peak top molecular weight was calculated by the following formula (I) from GPC (gel permeation chromatography) after decomposition by the above-mentioned ozone decomposition method, and the value was evaluated by the following indexes.

[0249] ○: The area ratio S calculated by formula (I) is 40% or less

[0250] ×: The area ratio S calculated by formula (I) is greater than 40%

[0251] Area ratio S of ozone decomposition products up to the peak molecular weight = A / B×100···(I)

[0252] A: Peak area from molecular weight 200 to peak top molecular weight of ozone decomposition product by GPC

[0253] B: The total area of ​​the peak with a molecular weight of 200 or more in GPC of ozone decomposition products

[0254] (Hydrogenation rate of hydrogenated conjugated diene polymer)

[0255] pass 1The integral value of the unsaturated bond portion of the conjugated diene polymer before hydrogenation is obtained by H-NMR measurement. A large amount of methanol is then added to the reaction solution after the hydrogenation reaction to precipitate the hydrogenated conjugated diene polymer for recovery. The hydrogenated conjugated diene polymer is then extracted with acetone and vacuum dried. It is used as 1 The hydrogenation rate of the sample subjected to H-NMR measurement was measured. The measurement conditions were as follows.

[0256] <Measurement Conditions>

[0257] Measuring equipment: JNM-LA400 (manufactured by JEOL)

[0258] Solvent: deuterated chloroform

[0259] Test samples: Extracts before and after hydrogenation of polymers

[0260] Sample concentration: 50 mg / mL

[0261] Observation frequency: 400MHz

[0262] Chemical shift standard: TMS (tetramethylsilane)

[0263] Pulse delay: 2.904 seconds

[0264] Scan times: 64 times

[0265] Pulse width: 45°

[0266] Measurement temperature: 26℃

[0267] (Styrene block content of hydrogenated conjugated diene polymer)

[0268] The chain of 8 or more styrene structural units is regarded as a styrene block, and the styrene block amount is determined as follows. The rubber-like polymer is subjected to a 400 MHz radio wave using deuterated chloroform as a solvent. 1 The H-NMR spectrum was measured. From the spectrum, the ratio of the integrated value of the following (X) in each chemical shift range was determined to determine the amount of styrene blocks contained in the rubber-like polymer.

[0269] Styrene chains 8 or more: 6.00≦X<6.68

[0270] (Amount of ethylene structure in hydrogenated conjugated diene polymer)

[0271] Using hydrogenated conjugated diene polymers, 1 The ethylene structure content of the hydrogenated conjugated diene polymer was measured by H-NMR measurement under the following conditions.

[0272] <Measurement Conditions>

[0273] Measuring equipment: JNM-LA400 (manufactured by JEOL)

[0274] Solvent: deuterated chloroform

[0275] Test sample: Hydrogenated conjugated diene polymer

[0276] Sample concentration: 50 mg / mL

[0277] Observation frequency: 400MHz

[0278] Chemical shift standard: TMS (tetramethylsilane)

[0279] Pulse delay: 2.904 seconds

[0280] Scan times: 64 times

[0281] Pulse width: 45°

[0282] Measurement temperature: 26℃

[0283] (Modification rate of hydrogenated conjugated diene polymer)

[0284] The modification ratios of the hydrogenated conjugated diene polymers of Examples and Comparative Examples described below were measured by column adsorption GPC as follows.

[0285] The measurement is carried out by utilizing the property that the conjugated diene polymer modified with a functional group containing a nitrogen atom is adsorbed on the column.

[0286] The adsorption amount on the silica column was measured from the difference between the chromatogram obtained by measuring a sample solution containing the sample and low molecular weight internal standard polystyrene using a polystyrene column and the chromatogram obtained by measuring a sample solution using a silica column, and the modification rate was obtained.

[0287] Specifically, it is as follows.

[0288] <Preparation of sample solution>:

[0289] 10 mg of a measurement sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to prepare a sample solution.

[0290] <GPC measurement conditions using polystyrene columns>:

[0291] THF with 5 mmol / L triethylamine added was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. For the column, a guard column: a trade name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation, and a column: a trade name "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgelSuperH7000" manufactured by Tosoh Corporation were used. The chromatogram was obtained by using an RI detector (HLC8020 manufactured by Tosoh Corporation) at a column box temperature of 40°C and a THF flow rate of 0.6 mL / min.

[0292] <GPC measurement conditions using silica column>:

[0293] A product named "HLC-8320GPC" manufactured by Tosoh Corporation was used, THF was used as the eluent, 50 μL of the sample solution was injected into the device, and a chromatogram was obtained using an RI detector under the conditions of a column box temperature of 40°C and a THF flow rate of 0.5 ml / min. As for the column, a product named "Zorbax PSM-1000S", "PSM-300S", and "PSM-60S" were connected and used, and a product named "DIOL 4.6×12.5 mm5 micron" was connected as a guard column in the front section.

[0294] <Calculation method of modification rate>:

[0295] Set the overall peak area of ​​the chromatogram using a polystyrene column to 100, the peak area of ​​the sample to P1, and the peak area of ​​the standard polystyrene to P2; set the overall peak area of ​​the chromatogram using a silica column to 100, the peak area of ​​the sample to P3, and the peak area of ​​the standard polystyrene to P4, and calculate the modification rate (%) by the following formula.

[0296] Modification rate (%) = [1-(P2×P3) / (P1×P4)]×100

[0297] (In the above formula, P1+P2=P3+P4=100)

[0298] [Characteristics evaluation method]

[0299] (Mooney viscosity (ML) of hydrogenated conjugated diene polymer)

[0300] The Mooney viscosity was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with ISO 289. The sample was preheated at 100°C for 1 minute, and then the L-type rotor was rotated at 2 rpm. The torque was measured after 4 minutes to obtain the Mooney viscosity (ML (1+4) ).

[0301] (Cold Flow Resistance of Hydrogenated Conjugated Diene Polymers)

[0302] The sample heated to 60°C was filled in a rectangular container with a size of 210 mm long side, 105 mm short side and 200 mm deep, and compressed by applying a pressure of 3.5 MPa for 10 seconds with a barrel to obtain a rectangular molded body. Using the obtained molded body, a load of 5 kg was applied under the conditions of an external temperature of 25°C and a humidity of 50%, and the thickness change rate (%) was calculated by the following formula based on the thickness (H72) after being placed for 72 hours, and the thickness change index was further calculated.

[0303] Thickness change rate (%) = (H0-H72) × 100 / H0

[0304] Thickness change index = (change rate of thickness of hydrogenated conjugated diene polymer as reference) ÷ (change rate of thickness of hydrogenated conjugated diene polymer as evaluation object) × 100

[0305] H0 represents the thickness of the sample just after forming.

[0306] The smaller the thickness change rate and the thickness change index are, the smaller the cold flow of the sample during storage is and the better the handleability is.

[0307] The thickness variation index of the hydrogenated conjugated diene polymer to be evaluated was evaluated using the following index.

[0308] (For the hydrogenated conjugated diene polymer used as a reference, refer to the following Table 1)

[0309] ◎: Thickness variation index is 140 or more

[0310] ○: Thickness variation index is 120 or more and less than 140

[0311] △: Thickness variation index is 80 or more and less than 120

[0312] ×: Thickness variation index is less than 80

[0313] [Production of hydrogenated conjugated diene polymer]

[0314] (Preparation of Hydrogenation Catalyst)

[0315] In the Examples and Comparative Examples described below, a hydrogenation catalyst for producing a hydrogenated conjugated diene polymer was prepared by the following method.

[0316] 1 L of dried and purified cyclohexane was placed in a nitrogen-substituted reaction container, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added, and a n-hexane solution containing 200 mmol of trimethylaluminum was added while stirring thoroughly. The mixture was reacted at room temperature for about 3 days to obtain a hydrogenation catalyst.

[0317] (Example 1: Production of hydrogenated conjugated diene polymer A1)

[0318] Cyclohexane 22000 g, tetrahydrofuran (THF) 30 mmol, 2,2-di(2-tetrahydrofuryl)propane 7.0 mmol, styrene 450 g, 1,3-butadiene 2550 g were placed in a nitrogen-purged 40 L autoclave reactor. The temperature of the reactor contents was adjusted to 43° C., and then a cyclohexane solution containing 40.0 mmol of n-butyl lithium was added to initiate polymerization, and polymerization was carried out under adiabatic conditions.

[0319] Two minutes after the reaction temperature reached the peak, 8.0 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane was added as a modifier to react with the active sites of the polymer for 20 minutes. Thereafter, 8.0 mmol of methanol was added to the polymer solution as a reaction terminator to obtain a conjugated diene polymer solution before hydrogenation.

[0320] The following reactor is used in the subsequent hydrogenation reaction step: it is equipped with a rotary stirrer with a rotation speed of 114 rpm, an internal capacity of 40 L, an L / D (L: height of the reactor, D: diameter of the reactor) of 2.2, 3 nozzles at the top and bottom (nozzle A, nozzle B and nozzle C at the top, nozzle D, nozzle E and nozzle F at the bottom), and further has 1 nozzle (nozzle G) on the central side of the reactor.

[0321] The temperature of the reactor was adjusted to 90°C, and then the conjugated diene polymer solution obtained above (polymer concentration 12% by mass) was supplied from the nozzle A at the top of the reactor at a polymer amount of 1.7 kg / h, and the hydrogenation catalyst prepared as described above was further added to the polymer solution in an amount of 100 ppm based on titanium relative to the amount of monomers fed, and the solution was adjusted so that the liquid level in the reactor reached 60%, and discharged from the nozzle D at the bottom of the reactor. At this time, the average residence time τ of the polymer was 70 minutes, and H / D (H: height of the liquid level, D: diameter of the reactor) was 1.3.

[0322] Thereafter, hydrogen was instantly introduced into the reactor from the nozzle E at the bottom of the reactor so as to reach 0.6 MPa, and the supply was immediately stopped. Thereafter, the polymer flowing out from the discharge nozzle D of the reactor was sampled every 10 minutes to measure the hydrogenation rate.

[0323] The results of the hydrogenation rate obtained based on the pulse response method were plotted against the average residence time τ and fitted using the following formula (2). As a result, an approximate value of 1.1 was obtained as the number N of complete mixing tanks.

[0324] [Number 3]

[0325]

[0326] Under the above reactor conditions, hydrogen was continuously supplied so as to achieve 0.6 MPa to carry out a hydrogenation reaction.

[0327] Next, 12.6 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid n-octadecyl ester and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol as antioxidants were added to the obtained hydrogenated conjugated diene polymer solution. Then, an aqueous solution (temperature: 80° C.) adjusted to pH 8.5 (pH of 80° C. measured by glass electrode method, the same below) by ammonia as a pH adjuster was added to a desolventizing tank, and the above hydrogenated conjugated diene polymer solution was further added to the desolventizing tank (the ratio of the aqueous solution to 100 parts by mass of the polymer solution was 200 parts by mass), and the solvent was removed by stripping (steam temperature: 190° C.) for 2 hours in the liquid phase (temperature: 95° C.) of the desolventizing tank. Thereafter, the residual water was dried using a dryer to obtain a hydrogenated conjugated diene polymer A1.

[0328] The analysis values ​​of the hydrogenated conjugated diene polymer A1 are shown in Table 3 below.

[0329] (Comparative Example 1: Production of Hydrogenated Conjugated Diene Polymer A1')

[0330] Cyclohexane 22000g, tetrahydrofuran (THF) 30mmol, 2,2-di(2-tetrahydrofuryl)propane 7.0mmol, styrene 450g, 1,3-butadiene 2550g were placed in a nitrogen-purged 40L autoclave reactor. The temperature of the reactor contents was adjusted to 43°C, and a cyclohexane solution containing 40.0mmol of n-butyl lithium was added to initiate polymerization, and polymerization was carried out under adiabatic conditions.

[0331] 2 minutes after the reaction temperature reached the peak, 8.0 mmol of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane was added as a modifier to react with the active sites of the conjugated diene polymer for 20 minutes. 8.0 mmol of methanol was then added to the conjugated diene polymer solution as a reaction terminator to obtain a conjugated diene polymer solution before hydrogenation.

[0332] In the subsequent hydrogenation reaction step, a reactor having a rotary stirrer with a rotation speed of 114 rpm, a content of 40 L, and an L / D of 2.2 was used. After the temperature of the reactor was adjusted to 90° C., the total amount of the conjugated diene polymer solution obtained above (polymer concentration 12% by mass) was filled into the reactor, and the hydrogenation catalyst prepared as described above was further added to the conjugated diene polymer solution in an amount of 100 ppm based on titanium relative to the amount of monomers fed, and hydrogen was filled into the reactor to achieve a hydrogenation reaction of 0.6 MPa for 70 minutes. Next, 12.6 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid n-octadecyl ester and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol as antioxidants were added to the obtained polymer solution, and then an aqueous solution (temperature: 80° C.) adjusted to pH 8.5 (pH of 80° C. measured by glass electrode method, the same below) with ammonia as a pH adjuster was added to a desolventizing tank, and the above hydrogenated conjugated diene polymer solution was further added to the desolventizing tank (the ratio of the aqueous solution to 100 parts by mass of the polymer solution was 200 parts by mass), and the solvent was removed by steam stripping (steam temperature: 190° C.) for 2 hours in the liquid phase (temperature: 95° C.) of the desolventizing tank. Thereafter, the residual water was dried using a dryer to obtain a hydrogenated conjugated diene polymer A1′.

[0333] Table 3 shows the analysis values ​​of the hydrogenated conjugated diene polymer A1′.

[0334] (Example 2: Production of hydrogenated conjugated diene polymer A2)

[0335] Cyclohexane 22000g, tetrahydrofuran (THF) 30mmol, 2,2-di(2-tetrahydrofuranyl)propane 7.0mmol, styrene 240g were added to a nitrogen-purged autoclave reactor with an internal volume of 40L, and the temperature of the reactor contents was adjusted to 43°C. A cyclohexane solution containing 40.0mmol of n-butyl lithium was added to initiate polymerization, and polymerization was carried out for 10 minutes under adiabatic conditions. Subsequently, styrene 210g and 1,3-butadiene 2550g were further added, and polymerization was carried out under adiabatic conditions. A hydrogenated conjugated diene polymer A2 was obtained by the same method as in Example 1 above, except that the polymerization was carried out under adiabatic conditions.

[0336] (Comparative Example 2: Production of Hydrogenated Conjugated Diene Polymer A2')

[0337] Cyclohexane 22000g, tetrahydrofuran (THF) 30mmol, 2,2-di(2-tetrahydrofuranyl)propane 7.0mmol, styrene 360g were added to a nitrogen-purged autoclave reactor with an internal volume of 40L, and the temperature of the reactor contents was adjusted to 43°C. A cyclohexane solution containing 40.0mmol of n-butyl lithium was added to initiate polymerization, and polymerization was carried out for 10 minutes under adiabatic conditions. Subsequently, styrene 90g and 1,3-butadiene 2550g were further added and polymerization was carried out under adiabatic conditions. A hydrogenated conjugated diene polymer A2' was obtained by the same method as in Example 1 above, except that polymerization was carried out under adiabatic conditions.

[0338] (Comparative Example 3: Production of Hydrogenated Conjugated Diene Polymer A3')

[0339] A hydrogenated conjugated diene polymer A3' was obtained in the same manner as in Comparative Example 1 except that the reaction time of the hydrogenation step was 100 minutes.

[0340] (Comparative Example 4: Production of Hydrogenated Conjugated Diene Polymer A4')

[0341] A hydrogenated conjugated diene polymer A4' was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of n-butyllithium, the amount of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane, and the amount of methanol were 64 mmol.

[0342] (Comparative Example 5: Production of Hydrogenated Conjugated Diene Polymer A5')

[0343] A hydrogenated conjugated diene polymer A5' was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of n-butyllithium, the amount of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane, and the amount of methanol were 1.3 mmol.

[0344] (Example 3: Production of hydrogenated conjugated diene polymer A3)

[0345] Hydrogenated conjugated diene polymer A3 was obtained by the same method as in Example 1, except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 6.1 mmol, the amount of n-butyllithium was 35 mmol, the amount of methanol was 35 mmol, and 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane was not added.

[0346] (Comparative Example 6: Production of Hydrogenated Conjugated Diene Polymer A6')

[0347] A hydrogenated conjugated diene polymer A6′ was obtained by the same method as in Comparative Example 1, except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 6.1 mmol, the amount of n-butyllithium was 35 mmol, the amount of methanol was 35 mmol, and 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilacyclopentane was not added.

[0348] (Example 4: Production of hydrogenated conjugated diene polymer A4)

[0349] Hydrogenated conjugated diene polymer A4 was obtained by the same method as in Example 1 except that 2,2-di(2-tetrahydrofuryl)propane was used at 6.1 mmol, n-butyl lithium was used at 35 mmol, 1,3-dimethyl-2-imidazolidinone was used at 28 mmol, and methanol was used at 7.0 mmol.

[0350] (Comparative Example 7: Production of Hydrogenated Conjugated Diene Polymer A7')

[0351] A hydrogenated conjugated diene polymer A7' 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-butyl lithium, 28 mmol of 1,3-dimethyl-2-imidazolidinone and 7.0 mmol of methanol were used.

[0352] (Example 5: Production of hydrogenated conjugated diene polymer B1)

[0353] A hydrogenated conjugated diene polymer B1 was obtained in the same manner as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 4.6 mmol.

[0354] (Comparative Example 8: Production of Hydrogenated Conjugated Diene Polymer B1')

[0355] A hydrogenated conjugated diene polymer B1′ was obtained in the same manner as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 4.6 mmol.

[0356] (Example 6: Production of hydrogenated conjugated diene polymer B2)

[0357] A hydrogenated conjugated diene polymer B2 was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol, 240 g, and 2760 g.

[0358] (Comparative Example 9: Production of Hydrogenated Conjugated Diene Polymer B2')

[0359] A hydrogenated conjugated diene polymer B2′ was obtained in the same manner as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol.

[0360] (Example 7: Production of Hydrogenated Conjugated Diene Polymer B3)

[0361] A hydrogenated conjugated diene polymer B3 was obtained in the same manner as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 19.5 mmol, 780 g, and 2220 g.

[0362] (Comparative Example 10: Production of Hydrogenated Conjugated Diene Polymer B3')

[0363] A polymer B3' was obtained by the same method as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 19.5 mmol, the amount of styrene was 780 g, and the amount of 1,3-butadiene was 2220 g.

[0364] (Example 8: Production of Hydrogenated Conjugated Diene Polymer B4)

[0365] A hydrogenated conjugated diene polymer B4 was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, the amount of styrene was 1200 g, and the amount of 1,3-butadiene was 1800 g.

[0366] (Comparative Example 11: Production of Hydrogenated Conjugated Diene Polymer B4')

[0367] A hydrogenated conjugated diene polymer B4′ was obtained in the same manner as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, the amount of styrene was 1200 g, and the amount of 1,3-butadiene was 1800 g.

[0368] (Example 9: Production of Hydrogenated Conjugated Diene Polymer B5)

[0369] A hydrogenated conjugated diene polymer B5 was obtained by the same method as in Example 1 except that styrene was not added and the amount of 1,3-butadiene was 3000 g.

[0370] (Comparative Example 12: Production of Hydrogenated Conjugated Diene Polymer B5')

[0371] A hydrogenated conjugated diene polymer B5' was obtained by the same method as in Comparative Example 1 except that styrene was not added and the amount of 1,3-butadiene was 3000 g.

[0372] (Example 10: Production of Hydrogenated Conjugated Diene Polymer C1)

[0373] A hydrogenated conjugated diene polymer C1 was obtained in the same manner as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol, 240 g, and 2760 g.

[0374] (Example 11: Production of hydrogenated conjugated diene polymer C2)

[0375] A hydrogenated conjugated diene polymer C2 was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, the amount of styrene was 240 g, the amount of 1,3-butadiene was 2760 g, and the polymer supply rate in the hydrogenation reaction step was 1.5 kg / h.

[0376] (Example 12: Production of Hydrogenated Conjugated Diene Polymer C3)

[0377] Hydrogenated conjugated diene polymer C3 was obtained by the same method as in Example 1 except that 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, and the polymer supply rate in the hydrogenation reaction step was 1.2 kg / h.

[0378] (Example 13: Production of hydrogenated conjugated diene polymer C4)

[0379] Hydrogenated conjugated diene polymer C4 was obtained by the same method as in Example 1 except that 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, and the polymer supply rate in the hydrogenation reaction step was 2.7 kg / h.

[0380] (Example 14: Production of hydrogenated conjugated diene polymer C5)

[0381] Hydrogenated conjugated diene polymer C5 was obtained by the same method as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, the amount of 1,3-butadiene, and the amount of polymer supplied in the hydrogenation reaction step were 3.3 kg / h.

[0382] (Example 15: Production of hydrogenated conjugated diene polymer C6)

[0383] Hydrogenated conjugated diene polymer C6 was obtained by the same method as in Example 1 except that 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, and the polymer supply rate in the hydrogenation reaction step was 5.8 kg / h.

[0384] (Comparative Example 13: Production of Hydrogenated Conjugated Diene Polymer C1')

[0385] A hydrogenated conjugated diene polymer C1′ was obtained in the same manner as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol.

[0386] (Comparative Example 14: Production of Hydrogenated Conjugated Diene Polymer C2')

[0387] A 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, 2760 g of 1,3-butadiene, and the hydrogenation reaction step was not performed.

[0388] (Comparative Example 15: Production of Hydrogenated Conjugated Diene Polymer C3')

[0389] A 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 of the hydrogenation step were 35 minutes.

[0390] (Comparative Example 16: Production of Hydrogenated Conjugated Diene Polymer C4')

[0391] A 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 the reaction time of the hydrogenation step were 20 minutes.

[0392] (Example 16: Production of hydrogenated conjugated diene polymer D1)

[0393] A hydrogenated conjugated diene polymer D1 was obtained in the same manner as in Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol, 240 g, and 2760 g.

[0394] (Example 17: Production of hydrogenated conjugated diene polymer D2)

[0395] 2,2-bis(2-tetrahydrofuranyl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, the reaction time of the hydrogenation step was 81 minutes, 70 minutes, and 55 minutes, and 1 / 3 of the content was discharged at each time. Three hydrogenated conjugated diene polymers with different hydrogenation rates were obtained by the same method as in Example 1. Thereafter, the obtained hydrogenated conjugated diene polymers 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.

[0396] (Example 18: Production of hydrogenated conjugated diene polymer D3)

[0397] 2,2-di(2-tetrahydrofuranyl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, and the reaction time of the hydrogenation step was changed to 105 minutes, 81 minutes, 70 minutes, 55 minutes, and 42 minutes. These five hydrogenated conjugated diene polymers with different hydrogenation rates were obtained by the same method as in Example 1. Thereafter, the obtained five hydrogenated conjugated diene polymers were mixed in such a manner that the contents were the same, thereby obtaining a hydrogenated conjugated diene polymer D3. At this time, the value of the hydrogenation rate distribution HWD was 1.04.

[0398] (Example 19: Production of hydrogenated conjugated diene polymer D4)

[0399] A hydrogenated conjugated diene polymer D4 was obtained by 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 polymer solution was supplied from the nozzle F at the bottom of the reactor and discharged from the nozzle B at the top of the reactor in the hydrogenation step. At this time, the value of the number of complete mixing tanks N based on the pulse response method was 2.3.

[0400] (Example 20: Production of hydrogenated conjugated diene polymer D5)

[0401] Hydrogenated conjugated diene polymer D5 was obtained by the same method as in Example 1 except that 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, styrene was 240 g, 1,3-butadiene was 2760 g, and the rotation speed in the hydrogenation step was 70 rpm. At this time, the value of the number of complete mixing tanks N based on the pulse response method was 1.3.

[0402] (Example 21: Production of hydrogenated conjugated diene polymer D6)

[0403] The amount of 2,2-di(2-tetrahydrofuryl)propane was 11.6 mmol, the amount of styrene was 240 g, the amount of 1,3-butadiene was 2760 g, and in the hydrogenation step, 20% of the polymer solution supplied from the nozzle A at the top of the reactor was supplied from the nozzle G at the center side of the reactor, and the number of complete mixing tanks N was changed to 1.2, and a hydrogenated conjugated diene polymer D6 was obtained by the same method as in Example 19. At this time, the value of the number of complete mixing tanks N based on the pulse response method was 1.2.

[0404] (Example 22: Production of hydrogenated conjugated diene polymer D7)

[0405] A hydrogenated conjugated diene polymer D7 was obtained by the same method 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, a rotation speed of 20 rpm in the hydrogenation step, a polymer supply amount of 2.3 kg / h, and a liquid level in the reactor of 80%. At this time, H / D (H: height of the liquid level, D: diameter of the reactor) was 1.8, and the value of the number of complete mixing tanks N based on the pulse response method was 2.2.

[0406] (Comparative Example 17: Production of Hydrogenated Conjugated Diene Polymer D1')

[0407] A hydrogenated conjugated diene polymer D1′ was obtained in the same manner as in Comparative Example 1 except that the amount of 2,2-di(2-tetrahydrofuryl)propane, the amount of styrene, and the amount of 1,3-butadiene were changed to 11.6 mmol, 240 g, and 2760 g.

[0408] [Evaluation of rubber compositions containing hydrogenated conjugated diene polymers A1 to D1']

[0409] The respective components were mixed according to the compounding ratios shown in Table 2 below by the method described below to obtain a rubber composition.

[0410] In addition, the addition amount of each compounding agent in Table 2 is shown as the mass part with respect to 100 mass parts of the rubber component which does not contain the rubber softener, that is, the hydrogenated conjugated diene polymer.

[0411] (Mixing method)

[0412] In the first stage of kneading, materials other than sulfur and vulcanization accelerator were kneaded using a sealed mixer (content 0.5 L) equipped with a temperature control device at a filling rate of 65% and a rotor speed of 50 to 90 rpm. The temperature of the sealed mixer was controlled at this time to obtain a mixed product at a discharge temperature of 150 to 160°C.

[0413] Next, as the second stage of kneading, the mixture obtained above is cooled to room temperature and then kneaded again to improve the dispersion of the reinforcing filler. In this case, the discharge temperature of the mixture is also adjusted to 150 to 160° C. by temperature control of the mixer.

[0414] After cooling, as the third stage of kneading, a vulcanization accelerator and sulfur were added and kneaded using an open roll mill set at 70° C. to obtain an unvulcanized rubber composition.

[0415] Thereafter, the rubber composition was molded and vulcanized at 160° C. for a predetermined vulcanization time using a vulcanization press to obtain a vulcanized rubber composition. The vulcanization time was a value obtained by adding 5 minutes to the 90% vulcanization time of the unvulcanized rubber composition.

[0416] The vulcanized rubber compositions were evaluated by the following methods.

[0417] [Evaluation items and test methods]

[0418] The unvulcanized rubber composition and the vulcanized rubber composition obtained were subjected to the following evaluations. The results are shown in Tables 3 to 6 below.

[0419] ((1) Processability (Mooney viscosity (compound ML)))

[0420] The unvulcanized rubber composition obtained above was used as a sample, and the viscosity was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho) according to ISO 289 after preheating at 130°C for 1 minute and rotating the rotor at 2 rpm for 4 minutes.

[0421] The measurement results of the unvulcanized rubber composition of the hydrogenated conjugated diene polymer used as a comparison standard were set to 100 and indexed, and judgment was made according to the following indicators.

[0422] The hydrogenated conjugated diene polymer used as a reference is shown in Table 1 below.

[0423] ◎: Index less than 80

[0424] ○: Index is 80 or more and less than 90

[0425] △: Index is 90 or more and less than 110

[0426] ×: Index is 110 or above

[0427] ((2) Tensile properties)

[0428] The vulcanized rubber composition obtained above was used as a sample, and the tensile properties were measured in accordance with the tensile test method of JIS K6251.

[0429] The measurement results of the vulcanized rubber composition of the hydrogenated conjugated diene polymer used as a comparison standard were set to 100 and indexed, and judgment was made according to the following indicators.

[0430] The hydrogenated conjugated diene polymer used as a reference is shown in Table 1 below.

[0431] <Tensile Strength (TB)>

[0432] ◎: Index is 120 or above

[0433] ○: Index is 110 or more and less than 120

[0434] △: Index is 90 or more and less than 110

[0435] ×: Index is less than 90

[0436] <Elongation at break (EB)>

[0437] ◎: Index is 120 or above

[0438] ○: Index is 110 or more and less than 120

[0439] △: Index is 90 or more and less than 110

[0440] ×: Index is less than 90

[0441] ((3) Ozone resistance)

[0442] A long strip sample (length 6 cm × width 1 cm × thickness 2.0 mm) was punched out from the vulcanized rubber composition obtained above, placed in an ozone tank (40°C, 50 pphm), and left to stand for 96 hours at 20% elongation. The long strip sample (vulcanized rubber sheet) was then observed, and the number of cracks with a length of more than 1 mm on the surface was counted. The number of cracks in the vulcanized rubber sheet of hydrogenated conjugated diene polymer used as a comparison standard was then indexed as 100, and judgment was made according to the following indicators.

[0443] The hydrogenated conjugated diene polymer used as a reference is shown in Table 1 below.

[0444] ◎: Index is less than 60, or the vulcanized rubber sheet has no cracks

[0445] ○: Index is 60 or more and less than 80

[0446] △: Index is 80 or more and less than 120

[0447] ×: The index is 120 or more, or the vulcanized rubber sheet is broken

[0448] ((4) Fuel-saving performance)

[0449] The torsional vibration mode was measured at 50°C, 10 Hz, and 3% strain using a viscoelasticity tester "ARES" manufactured by Rheometric Scientific, and the obtained tan δ was used as an index of fuel efficiency. Then, the measurement result of the vulcanized rubber composition of the hydrogenated conjugated diene polymer as a comparison standard was set as 100 and indexed, and judgment was made according to the following indicators.

[0450] The hydrogenated conjugated diene polymer used as a reference is shown in Table 1 below.

[0451] ◎: Index less than 80

[0452] ○: Index is 80 or more and less than 90

[0453] △: Index is 90 or more and less than 110

[0454] ×: Index is 110 or above

[0455] In Table 2 below, the trade names used for the components are as follows.

[0456] ·Hydrogenated conjugated diene polymers: A1~D1'

[0457] ·Natural rubber: RSS No.3 (manufacturer: UNIMAC RUBBER CO., LTD. (Thailand), supplier: Marubeni Techno Rubber)

[0458] Carbon black: SEAST SO (FEF) manufactured by Tokai Carbon Co., Ltd. (nitrogen adsorption specific surface area 42m 2 / g)

[0459] Softener: Process Oil PF30 (SRAE oil) manufactured by JXTG Energy Corporation

[0460] Zinc white: Zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.

[0461] Stearic acid: Lunac S-90V manufactured by Kao Corporation

[0462] Wax: Sunnoc manufactured by Ouchi Shinko Chemical Co., Ltd.

[0463] Anti-aging agent: Nocrac 6C manufactured by Ouchi Shinko Chemical Co., Ltd.

[0464] ·Sulfur: Powdered sulfur Sulfax 200S manufactured by Tsurumi Chemical Co., Ltd.

[0465] Vulcanization accelerator: TBBS Sanceler NS-G (N-tert-butylbenzothiazole-2-sulfonamide) manufactured by Sanxin Chemical Co., Ltd.

[0466] [Table 1]

[0467]

[0468] [Table 2]

[0469] mixture Number of servings [phr] Hydrogenated conjugated diene polymers 100 Carbon Black 53 Softener 7 Zinc White 3 Stearic acid 2 wax 1 Anti-aging agents 3 sulfur 1.6 Vulcanization accelerator 0.7

[0470]

[0471]

[0472]

[0473]

[0474] From Tables 3 to 6, it was confirmed that the polymers of Examples 1 to 22 were superior in processability and cold flow resistance compared to the "base hydrogenated conjugated diene polymer" described in Table 1, and were superior in ozone resistance and breaking properties when used as rubber compositions.

[0475] As described above, it can be seen that the present invention can provide a hydrogenated conjugated diene polymer, which can ensure the processability and cold flow resistance of the hydrogenated conjugated diene polymer and the rubber composition made of the same, and has excellent ozone resistance, fracture properties and low hysteresis loss when made into a rubber composition.

[0476] This application is based on the Japanese patent application (Japanese Patent Application No. 2022-178955) filed with the Japan Patent Office on November 8, 2022, and its contents are incorporated into this specification as a reference.

[0477] Industrial Applicability

[0478] The present invention has industrial applicability as a tire body such as a tire tread or bead, a gasket or a spacer, a sealing material, an anti-vibration rubber, an anti-vibration rubber, a shock absorber, a conveyor belt, a shoe outsole or a shoe midsole, a car weather strip, a glass run channel, a trunk lid, a railway vehicle component, an aircraft component, a waterproof sheet, an engine bracket, an air spring, a rubber glove, a medical and sanitary product, an industrial hose and a hose for various purposes, a battery case, an adhesive, a wire coating, a window frame rubber, a rubber roller for OA equipment or textiles, a numeric keypad, a keyboard cover, underwater glasses, a swimming cap, a container bag, marine-related components, an indoor floor material, an artificial muscle material, and materials for various industrial products.

Claims

1. A hydrogenated conjugated diene polymer which satisfies the following conditions (i) to (iii), <Condition (i)> It is a random polymer containing conjugated diene monomer units and containing or not containing 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 Above 200×10 4 the following; <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 claim 1, wherein The hydrogenation rate was 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 mass % or more. 5 . The hydrogenated conjugated diene polymer according to claim 1 , comprising an aromatic vinyl monomer unit.

6. A method for producing a hydrogenated conjugated diene polymer, which is the method for producing a hydrogenated conjugated diene polymer according to any one of claims 1 to 5, wherein: The method has the following steps: The polymerization step yields a weight average molecular weight of 10×10 4 Above 200×10 4 The following, a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass; A hydrogenation step to obtain a plurality of hydrogenated conjugated diene polymers having different hydrogenation rates; as well as a mixing step of mixing the plurality of hydrogenated conjugated diene polymers so that the hydrogenation rate distribution HWD represented by the following formula (1) is 1.005 or more; [Number 1] In formula (1), n ​​represents the total number of hydrogenated conjugated diene polymers having different hydrogenation rates, and w i Indicates that there is a specific hydrogenation rate H i The mass fraction of the hydrogenated conjugated diene polymer in all hydrogenated conjugated diene polymers.

7. A method for producing a hydrogenated conjugated diene polymer, which is the method for producing a hydrogenated conjugated diene polymer according to any one of claims 1 to 5, wherein: The method has the following steps: The polymerization step yields a weight average molecular weight of 10×10 4 Above 200×10 4 The following, a conjugated diene polymer having an aromatic vinyl monomer block content of less than 10% by mass; as well as A hydrogenation step of hydrogenating the conjugated diene polymer. The hydrogenation step is made into a continuous process, and the number N of completely mixed tank trains when fitting the residence time distribution in the reactor by the impulse response method in the completely mixed tank train model is set to 1.0 to 2.

5.

8. The method for producing a hydrogenated conjugated diene polymer according to claim 7, wherein: In the reactor of the hydrogenation step, hydrogen and the conjugated diene polymer are supplied from opposite directions, or hydrogen and / or the conjugated diene polymer are supplied from a plurality of positions.

9. The method for producing a hydrogenated conjugated diene polymer according to claim 7, wherein: In the continuous process, a stirred tank reactor is used, the conjugated diene polymer and the hydrogenation catalyst are supplied from the upper part of the tank of the stirred tank reactor, and hydrogen is supplied from the bottom of the tank of the stirred tank reactor while stirring is performed. The hydrogenated conjugated diene polymer is extruded from the bottom of the stirred tank reactor.

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