Rubber-like polymers, methods for manufacturing rubber-like polymers, rubber compositions, and tire treads

Abstract

The present invention provides a rubber-like polymer wherein the total content of the structure represented by formula (1) C1 and the content of the structure represented by formula (2) C2 is 40 mol% or more and 60 mol% or less, the content of the structure represented by formula (3) C3 is 15 mol% or more and 60 mol% or less, the content of the structure represented by formula (4) C4 is 2 mol% or more and 25 mol% or less, the content of aromatic vinyl monomer units S is 4 mol% or more and 18 mol% or less, the weight-average molecular weight determined by gel permeation chromatography (GPC) is 300,000 or more, and the modification rate determined by column adsorption GPC is 60% by mass or more.

Description

Technical Field

[0001] This invention relates to rubber-like polymers, methods for manufacturing rubber-like polymers, rubber compositions, and tire treads. Background Technology

[0002] In recent years, from the perspective of reducing environmental impact, high standards of fuel efficiency and mechanical strength have been required for automobile tires.

[0003] Since the fuel efficiency of tires is directly related to the fuel consumption of a vehicle, it also becomes an indicator of environmental impact. Furthermore, since the mechanical strength of tires is directly related to their lifespan, it has a significant impact on environmental impact.

[0004] As a tire rubber material that meets the above requirements, hydrogenated rubber polymers, which are made by adding hydrogen to rubber polymers, have been known in recent years.

[0005] For example, in Patent Documents 1 to 4, a rubber composition containing a rubber-like polymer having an ethylene structure and incorporating crosslinkable unsaturated groups was proposed for the purpose of improving mechanical strength and reducing compression set.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 150645

[0009] Patent Document 2: International Publication No. 2019 / 151126

[0010] Patent Document 3: International Publication No. 2019 / 151127

[0011] Patent Document 4: International Publication No. 2019 / 078083 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] It is generally known that the fuel-saving properties and mechanical strength of vulcanizates of rubbery polymers largely depend on the proportion of aromatic vinyl monomers in the rubbery polymer and the proportion of repeating units from conjugated diene monomers (1,2-vinyl binding ratio, 1,4-vinyl binding ratio).

[0014] Specifically, if the rubber-like polymer has a high proportion of 1,2-vinyl groups and a low proportion of aromatic vinyl monomers, the sulfide will have excellent fuel-saving performance, but its tensile strength, which is one of the mechanical strengths, will tend to decrease.

[0015] On the other hand, hydrogenation of a rubbery polymer with saturated bonds in the main chain to improve mechanical strength is known as one of the means to improve the balance of properties.

[0016] However, hydrogenating unsaturated bonds to form saturated bonds results in a significant decrease in the vulcanization rate during sulfide production. This reduced vulcanization rate leads to decreased tire productivity and may further impair co-crosslinking with other rubber materials, posing a serious problem.

[0017] Therefore, the object of the present invention is to provide a rubber-like polymer that can achieve a practically sufficient vulcanization rate and a rubber composition that can achieve an excellent balance between fuel-saving performance and mechanical strength.

[0018] Methods for solving problems

[0019] In order to solve the problems of the prior art, the inventors conducted in-depth research and exploration, and found that by having a specific structural ratio and a specific molecular weight, a polymer that can perform the desired properties can be obtained, thus completing the present invention.

[0020] That is, the present invention is as follows. [1]

[0022] A rubber-like polymer, wherein,

[0023] The sum of the content C1 of the structure represented by formula (1) and the content C2 of the structure represented by formula (2) is 40 mol% or more and 60 mol% or less.

[0024] The content of the structure represented by the following formula (3) C3 is 15 mol% or more and 60 mol% or less.

[0025] The content of the structure represented by the following formula (4) C4 is more than 2 mol% and less than 25 mol%.

[0026] The content of aromatic vinyl monomer units S is between 4 mol% and 18 mol%.

[0027] The weight-average molecular weight, as determined by gel permeation chromatography (GPC), is over 300,000.

[0028] The modification rate, as determined by column adsorption GPC, was over 60% by mass.

[0029] [Chemistry 1]

[0030] [2]

[0032] As described in [1] above, a rubber-like polymer, wherein,

[0033] The total content of the structure represented by formula (1) above, C1, and the content of the structure represented by formula (2) above, C2, is 40 mol% or more and 60 mol% or less.

[0034] The content of the structure represented by the above formula (3) C3 is more than 15 mol% and less than 60 mol%.

[0035] The content of the structure represented by the above formula (4) is more than 5 mol% and less than 25 mol%.

[0036] The content of aromatic vinyl monomer units S is between 4 mol% and 15 mol%.

[0037] The weight-average molecular weight, determined by gel permeation chromatography (GPC), is above 300,000.

[0038] The modification rate, as determined by column adsorption GPC, was over 60% by mass. [3]

[0040] The rubber-like polymer described in [1] or [2] above, wherein the ratio of weight-average molecular weight Mw to Mooney viscosity ML measured at 100°C, Mw / (ML×10000), is 0.68 or more and 0.85 or less. [4]

[0042] The rubber-like polymer described in any one of [1] to [3] above, wherein the nitrogen content is more than 10 ppm and less than 80 ppm. [5]

[0044] The rubber-like polymer described in any one of [1] to [4] above, wherein the nitrogen content is more than 35 ppm and less than 80 ppm. [6]

[0046] The rubber-like polymer described in any one of [1] to [5] above, wherein the silicon content is more than 50 ppm and less than 200 ppm. [7]

[0048] A method for manufacturing a rubber-like polymer, which is a method for manufacturing a rubber-like polymer as described in any one of [1] to [6] above, comprising the following steps:

[0049] The conjugated diene compound was copolymerized with an aromatic vinyl compound, and the resulting copolymer was hydrogenated to a hydrogenation rate of less than 90%. [8]

[0051] A rubber composition comprising:

[0052] 100 parts by weight of rubber component, comprising any one of the rubber-like polymers described in [1] to [6] above; and

[0053] Crosslinking agent of 0.1 to 20 parts by weight. [9]

[0055] A rubber composition comprising:

[0056] 100 parts by weight of rubber component, comprising any one of the rubber-like polymers described in [1] to [6] above; and

[0057] Silane coupling agents, ranging from 0.1 parts by weight to 30 parts by weight.

[10]

[0059] A rubber composition comprising:

[0060] 100 parts by weight of rubber component, comprising any one of the rubber-like polymers described in [1] to [6] above; and

[0061] A plasticizer consisting of 1 to 60 parts by weight.

[11]

[0063] A rubber composition comprising:

[0064] 100 parts by weight of rubber component, comprising any one of the rubber-like polymers described in [1] to [6] above; and

[0065] 30 to 100 parts by weight of silicon dioxide.

[12]

[0067] A rubber composition comprising:

[0068] 100 parts by weight of rubber component, comprising any one of the rubber-like polymers described in [1] to [6] above; and

[0069] Carbon black of 1 part by weight to 100 parts by weight.

[13]

[0071] A tire tread comprising any one of the rubber compositions described in [8] to

[12] above.

[0072] The effects of the invention

[0073] According to the present invention, a rubber-like polymer can be provided, which can achieve a practically sufficient vulcanization rate and a rubber composition that achieves an excellent balance between fuel-saving performance and mechanical strength. Detailed Implementation

[0074] The specific embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail below.

[0075] It should be noted that the following embodiments are illustrative of the present invention, and the present invention is not limited to the following embodiments. The present invention can be suitably modified within the scope of its essential points.

[0076] [Rubber-like polymer]

[0077] In the rubber-like polymer of this embodiment,

[0078] The sum of the content C1 of the structure represented by formula (1) and the content C2 of the structure represented by formula (2) is 40 mol% or more and 60 mol% or less.

[0079] The content of the structure represented by the following formula (3) C3 is 15 mol% or more and 60 mol% or less.

[0080] The content of the structure represented by the following formula (4) C4 is more than 2 mol% and less than 25 mol%.

[0081] The content of aromatic vinyl monomer units S is between 4 mol% and 18 mol%.

[0082] The weight-average molecular weight, as determined by gel permeation chromatography (GPC), is over 300,000.

[0083] The modification rate, as determined by column adsorption GPC, was over 60% by mass.

[0084] [Chemistry 2]

[0085]

[0086] As described above, in the rubber-like polymer of this embodiment, by setting the content S of the aromatic vinyl monomer unit and the content C1 to C4 of the structure represented by the above formulas (1) to (4) to the above specific range, a practically sufficient vulcanization speed can be obtained when making the vulcanizate, and there is a tendency to obtain a rubber composition with an excellent balance between fuel-saving performance and mechanical strength.

[0087] The relationship between each structure and performance is explained below.

[0088] In the rubber-like polymer of this embodiment, the structure represented by formula (1) above is equivalent to, for example, a 1,2-vinyl bond unit of a conjugated diene compound, but as long as it is the same as the structure represented by formula (1) above, there is no particular limitation on its raw materials. In addition, the structure represented by formula (2) above is equivalent to, for example, a 1,2-vinyl bond unit of a conjugated diene compound formed by hydrogenation, but as long as it is the same as the structure represented by formula (2) above, there is no particular limitation on its raw materials.

[0089] When the total value of each structural unit constituting the rubbery polymer of this embodiment is set to 100 mol%, the total value of C1 and C2 is preferably 40 mol% or more and 60 mol% or less, preferably 45 mol% or more and 60 mol% or less, and more preferably 50 mol% or more and 60 mol% or less.

[0090] When the sum of C1 and C2 is within the above range, there is a tendency for sulfides to have excellent fuel-saving performance.

[0091] The structure represented by the above formula (3) is equivalent to, for example, the 1,4-vinyl binding unit of a conjugated diene compound, but as long as it is the same as the structure represented by the above formula (3), there is no particular limitation on its raw materials.

[0092] When the total value of each structural unit constituting the rubbery polymer of this embodiment is set to 100 mol%, C3 is 15 mol% or more and 60 mol% or less. Regarding the lower limit, it is preferably 20 mol% or more, and more preferably 30 mol% or more. Regarding the upper limit, it is preferably 50 mol% or less, and more preferably 40 mol% or less.

[0093] When C3 is within the above range, there is a tendency to prevent the sulfidation rate from becoming too slow during the production of sulfides.

[0094] The structure represented by the above formula (4) is equivalent to, for example, the structure formed by hydrogenation of the 1,4-vinyl binding unit of a conjugated diene compound, but as long as it is the same as the structure represented by the above formula (4), there is no particular limitation on its raw materials.

[0095] When the total value of each structural unit constituting the rubbery polymer of this embodiment is set to 100 mol%, C4 is 2 mol% or more and 25 mol% or less. Regarding the lower limit, it is preferably 5 mol% or more, more preferably 7 mol% or more, and even more preferably 10 mol% or more.

[0096] When C4 is within the above range, it tends to have excellent tensile strength after being made into a sulfide.

[0097] In addition, from the perspective of vulcanization rate, the upper limit of C4 is preferably 20 mol% or less, more preferably 18 mol% or less.

[0098] The content of the structures represented by formulas (1) to (4) in the rubbery polymer of this embodiment, C1 to C4, can be determined by... 1 The H-NMR measurements can be calculated, specifically, by the method described in the examples below.

[0099] When the total value of each structural unit constituting the rubbery polymer of this embodiment is set to 100 mol%, the content S of the aromatic vinyl monomer unit is 4 mol% or more and 18 mol% or less. Regarding the upper limit, it is preferably 15 mol% or less, more preferably 10 mol% or less, and even more preferably 7 mol% or less.

[0100] Regarding the lower limit value, it is preferably 4 mol% or more, and more preferably 6 mol% or more.

[0101] When S is within the above range, it tends to have excellent fuel-saving performance after being made into a sulfide.

[0102] The sulfur in the rubbery polymer of this embodiment can be calculated by NMR measurement, specifically by the method described in the examples below.

[0103] (Aromatic vinyl monomers)

[0104] The rubber-like polymer of this embodiment contains structural units derived from aromatic vinyl compounds (hereinafter also referred to as "aromatic vinyl monomer units").

[0105] Examples of aromatic vinyl compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinyl ethylbenzene, vinyl xylene, vinyl naphthalene, and diphenylethylene.

[0106] Of these, styrene is preferred from the perspective of ease of industrial acquisition.

[0107] They can be used individually or in combination with more than one type.

[0108] (Conjugated diene compounds)

[0109] In the rubber-like polymer of this embodiment, the structural unit represented by the above formulas (1) to (4) is preferably a structural unit derived from a conjugated diene compound (hereinafter also referred to as "conjugated diene monomer").

[0110] Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the perspective of ease of industrial acquisition, and 1,3-butadiene is more preferred.

[0111] They can be used individually or in combination with more than one type.

[0112] (Weight-average molecular weight of rubber-like polymers)

[0113] In the rubbery polymer of this embodiment, the weight-average molecular weight (Mw) determined by gel permeation chromatography (GPC) is 300,000 or more. Preferably, it is 400,000 or more, and more preferably 440,000 or more.

[0114] By making the Mw of the rubbery polymer of this embodiment 300,000 or more, the sulfide tends to have high tensile strength.

[0115] In this embodiment, the Mw of the rubber-like polymer is preferably 700,000 or less, more preferably 650,000 or less, and even more preferably 600,000 or less. By keeping the Mw below 700,000, when the rubber-like polymer of this embodiment is used in a tire composition, it exhibits excellent processability during mixing, sufficient dispersion of the filler, and excellent fuel-saving performance.

[0116] The weight-average molecular weight of the rubbery polymer can be calculated based on the molecular weight converted from polystyrene as determined by GPC, and can be determined by the method described in the examples below.

[0117] (Modification of rubber-like polymers)

[0118] In the rubber-like polymer of this embodiment, from the perspective of fuel-saving performance when used as a tire material, it is preferable to contain tin atoms, nitrogen atoms or silicon atoms, and more preferably to contain both nitrogen atoms and silicon atoms.

[0119] In this embodiment, the compound containing nitrogen atoms is called a modifier, and the addition of the modifier to the rubbery polymer is called modification.

[0120] In the rubbery polymer of this embodiment, the modification rate, as determined by column adsorption GPC method, is 60% by mass or more.

[0121] By achieving a modification rate of 60% or more by mass, there is a tendency to obtain excellent fuel-saving performance in sulfides.

[0122] The modification rate of the rubber-like polymer in this embodiment is more preferably 70% by mass or more, and even more preferably 75% by mass or more.

[0123] The modification rate can be determined using a chromatograph capable of separating modified components containing functional groups from unmodified components.

[0124] As an example of a method using this chromatograph, one can cite a gel permeation chromatography column that uses polar compounds such as silica, which can adsorb specific functional groups, as the packing material, and uses an internal standard of the non-adsorbed component for comparison to perform quantification (column adsorption GPC method).

[0125] More specifically, the modification rate can be obtained as follows: the amount of adsorption on the silica column is determined by the difference between the chromatogram of the sample solution containing the sample and the low molecular weight internal standard polystyrene measured using a polystyrene-based gel column and the chromatogram measured using a silica-based column, thereby obtaining the modification rate.

[0126] More specifically, the modification rate can be determined using the methods described in the examples.

[0127] In the rubber-like polymer of this embodiment, the modification rate can be controlled by adjusting the amount of modifier added and the reaction method, thereby controlling it within the above-mentioned numerical range.

[0128] For example, the following methods can be combined to control the polymerization conditions to achieve the aforementioned modification rate: a method of polymerization using an organolithium compound having at least one nitrogen atom in the molecule (described later) as a polymerization initiator; a method of copolymerizing a monomer having at least one nitrogen atom in the molecule; and a method of using a modifier with the structure described later.

[0129] (Nitrogen content)

[0130] In the rubber-like polymer of this embodiment, the nitrogen content, as determined by trace nitrogen analysis, is preferably 10 ppm or more and 80 ppm or less.

[0131] By setting the nitrogen content to 10 ppm or more, it tends to exhibit excellent tensile strength. More preferably, the nitrogen content is 20 ppm or more, further preferably 30 ppm or more, even more preferably 35 ppm or more, even more preferably 37 ppm or more, and particularly preferably 40 ppm or more.

[0132] In the rubber-like polymer of this embodiment, even if the number of nitrogen atoms in the modifier remains constant when the end is modified, the nitrogen content tends to decrease if the molecular chain lengthens and the molecular weight increases. When the molecular chain is long, the tensile strength is good when the nitrogen content is 10 ppm or more; on the other hand, when the molecular weight is small, it is preferable to set it to 35 ppm or more according to the molecular weight.

[0133] From a processability perspective, the nitrogen content of the rubbery polymer is preferably 80 ppm or less, more preferably 70 ppm or less, and even more preferably 60 ppm or less.

[0134] The nitrogen content can be determined by the method described in the examples below.

[0135] The nitrogen content can be controlled within the above-mentioned range by adjusting the type and amount of modifier.

[0136] When comparing the same rubbery polymer, a higher modification rate tends to lead to a higher nitrogen content. However, since nitrogen content also depends on the type and molecular weight of the modifier, it is not necessarily related to the modification rate. As a result, as mentioned above, the modification rate tends to affect the fuel-saving performance of rubbery polymers when used in tires, while nitrogen content tends to affect tensile strength.

[0137] In the rubber-like polymer of this embodiment, as a method for separately controlling the modification rate and nitrogen content, adding a modifier with a high nitrogen content is effective when it is desired to increase the nitrogen content while maintaining the modification rate. By using a modifier with a high nitrogen content, the silanization of the silane coupling agent can be promoted when the tire rubber composition using the rubber-like polymer is compounded, thus tending to obtain tires with high tensile strength. Similarly, adjusting the molecular weight can also be cited as a method for separately controlling the modification rate and nitrogen content of the rubber-like polymer. Specifically, by reducing the molecular weight of the rubber-like polymer, the nitrogen content can be changed while maintaining the modification rate.

[0138] (Modifier)

[0139] In the rubbery polymer of this embodiment, as described above, the modification rate is 60% by mass or more, and it has been modified using a modifier.

[0140] The modifier is not particularly limited, and any known modifier can be used. As a modifier, from the perspective of the fuel-saving performance of the vulcanizate of the rubber-like polymer of this embodiment, a compound having both nitrogen and silicon atoms is preferred, and an alkoxysilane compound containing a nitrogen group is more preferred.

[0141] Examples of nitrogen-containing alkoxysilane compounds include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silazane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silazane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silazane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silazaneheptane, and 2,2-dimethoxy-1 -(3-Dimethoxymethylsilylpropyl)-1-aza-2-silazopentane, 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silazopentane, 2-methoxy-2-methyl-1-(3-trimethoxysilylpropyl)-1-aza-2-silazopentane, 2-ethoxy-2-ethyl-1-(3-triethoxysilylpropyl)-1-aza-2-silazopentane, 2-methoxy-2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silazopentane, Cyclopentane, and 2-ethoxy-2-ethyl-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silazane, tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-methyldiethoxysilylpropyl)amine, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine, tetra[3-(2,2-dimethoxy-1-aza-2- [Silylcyclopentane]-1,3-propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-propanediamine, tetra(3-trimethoxysilylpropyl)-1,3-diaminomethylcyclohexane, and N1-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N1-methyl-N3-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine, 3-(4-methylpiperazin-1-yl)propyltriethoxysilane.

[0142] (Monomer units with unsaturated groups in rubber-like polymers)

[0143] The rubber-like polymer of this embodiment preferably contains more than 2% by mass of conjugated diene monomer units, myrcene, or other monomer units with unsaturated groups.

[0144] As a monomeric unit with unsaturated groups, it is not limited to conjugated diene monomeric units or myrcene, but may also include other monomeric units.

[0145] From an economic and manufacturing perspective, the rubber-like polymer of this embodiment preferably contains conjugated diene monomer units.

[0146] Since the conjugated diene monomer unit and myrcene have double bonds, the rubber-like polymer of this embodiment has crosslinkable unsaturated groups by having these monomer units.

[0147] The content of monomer units with unsaturated groups in the rubber-like polymer of this embodiment is closely related to the iodine value.

[0148] By ensuring that the content of monomer units with unsaturated groups, such as conjugated diene monomer units and myrcene, is 2% by mass or more, the rubber-like polymer of this embodiment is excellent in terms of ease of crosslinking.

[0149] The content of monomer units with unsaturated groups, such as conjugated diene monomer units and myrcene, is more preferably 3% by mass or more, and even more preferably 6% by mass or more.

[0150] Furthermore, the content of monomer units with unsaturated groups, such as conjugated diene monomer units and myrcene, is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. This results in excellent weather resistance and resistance to degradation over time.

[0151] From the perspectives of economy and manufacturability, conjugated diene monomer units, such as myrcene, which have unsaturated groups, are preferred as monomer units.

[0152] The content of monomer units with unsaturated groups in the rubber-like polymer of this embodiment can be determined by the NMR measurement method described in the following examples. By adjusting the amount of added conjugated diene monomer units, myrcene and other monomers with unsaturated groups, and the hydrogenation rate of the conjugated diene monomer, the values ​​can be controlled within the above range.

[0153] In this embodiment, the hydrogenation rate of the rubber-like polymer, the distribution of monomer units such as ethylene, conjugated diene monomers, myrcene, and vinyl aromatic monomers between or within molecules are not particularly limited; they can be uniform, non-uniform, or have a distribution.

[0154] (Silicon content of rubber-like polymers)

[0155] In this embodiment, the silicone content of the rubber-like polymer is preferably 50 ppm or more and 200 ppm or less.

[0156] By setting the silicon content to 50 ppm or higher, the interaction between the rubber-like polymer and the reinforcing material in the rubber composition of this embodiment is strengthened, resulting in excellent tensile strength.

[0157] The silicone content of the rubber-like polymer in this embodiment is more preferably 80 ppm or more, and even more preferably 100 ppm or more.

[0158] By keeping the silicon content at 200 ppm or less, discoloration caused by the time-related degradation of the rubber-like polymer can be suppressed. In this embodiment, the silicon content of the rubber-like polymer is more preferably 170 ppm or less, and even more preferably 150 ppm or less.

[0159] In the manufacturing process of rubber-like polymers, a coupling reaction is carried out using a silicon-containing coupling agent after the polymerization process. By adjusting the amount of the silicon-containing coupling agent added, the silicon content of the rubber-like polymer can be controlled within the aforementioned value range.

[0160] Mooney viscosity

[0161] The Mooney viscosity of the rubber-like polymer in this embodiment is an indicator that includes information such as the molecular weight, molecular weight distribution, degree of branching, and content of softener of the rubber-like polymer.

[0162] Regarding the Mooney viscosity of the rubber-like polymer of this embodiment, measured at 100°C, from the perspective of abrasion resistance, handling stability, and breaking strength when the crosslinking rubber composition containing the rubber-like polymer of this embodiment and the crosslinking agent is used in tires, it is preferably 50 or more, more preferably 60 or more, further preferably 70 or more, and even more preferably 90 or more.

[0163] On the other hand, from the perspective of the productivity of the rubber composition using the rubber-like polymer of this embodiment and the processability when making a rubber composition mixed with fillers, etc., the Mooney viscosity is preferably 200 or less, more preferably 150 or less, even more preferably 130 or less, and even more preferably 110 or less.

[0164] The method for determining Mooney viscosity can be the one specified in ISO 289, which is described later.

[0165] The Mooney viscosity of the rubber-like polymer in this embodiment can be controlled to the above-mentioned range by adjusting the amount and type of polymerization initiator and coupling agent added in the polymerization process of the rubber-like polymer.

[0166] (Ratio of weight-average molecular weight to Mooney viscosity of rubber-like polymers (Mw / (ML×10000)))

[0167] In the rubbery polymer of this embodiment, the ratio of weight-average molecular weight Mw to Mooney viscosity ML, Mw / (ML×10000), is preferably 0.68 or more and 0.85 or less.

[0168] Generally, ML (Metallurgical Mixture) tends to be strongly dependent on Mw (Metallurgical Weight). Increasing the Mw of a rubbery polymer can improve its mechanical strength, but simply increasing the Mw tends to increase the ML as well. A high ML will lead to poorer processability of the rubbery polymer and deteriorate the dispersibility of the filler. In other words, if Mw is increased to improve the mechanical strength of the rubbery polymer, the ML will increase, resulting in reduced processability.

[0169] As a method to sever the correlation between Mw and ML of a rubbery polymer, one can cite methods such as changing the branching structure of the rubbery polymer or changing the composition ratio of the rubbery polymer. For example, in the case where the structure is not straight but branched into three or more branches, even if the molecular weight is the same, the length of each molecular chain will be shorter compared to the straight chain case, and it tends to be easier to mix with other materials compared to the straight chain case.

[0170] In contrast, the inventors have discovered that by limiting the content of the structures C1, C2, C3, and C4 of the above formulas (1) to (4) as repeating units and the content S of the aromatic vinyl monomer units in a specified range in a rubber-like polymer, the Mw to ML ratio of the rubber-like polymer can be adjusted. The choice of which of the above formulas (1) to (4) structures is used during the polymerization of the conjugated diene—either 1,2-vinyl or 1,4-vinyl—and whether each is hydrogenated, is determined. However, the hydrogenation rates differ between 1,2-vinyl and 1,4-vinyl bonds, thus the control of the hydrogenation rate also affects the content C1 to C4 of the structures in formulas (1) to (4). Adjusting the amount of vinyl bonds and the hydrogenation rate in the rubber-like polymer to contain a specified structure at a specified content, thereby controlling the ML of the rubber-like polymer, is a novel technical concept that reduces the dependence of ML on Mw and broadens the design range of rubber-like polymers.

[0171] In the rubber-like polymer of this embodiment, from the viewpoint of obtaining high tear strength, Mw / (ML×10000) is preferably 0.68 or more and 0.85 or less.

[0172] The lower limit is more preferably 0.73 or higher, and even more preferably 0.78 or higher.

[0173] The upper limit is more preferably 0.84 or less, and even more preferably 0.80 or less.

[0174] By setting Mw / (ML×10000) within the above-mentioned numerical range, the rubber composition using the rubber-like polymer of this embodiment exhibits an excellent balance between mechanical strength and filler dispersibility, i.e., processability, and displays excellent tear strength.

[0175] Typically, the molecular weight (ML) of polymers is strongly dependent on the molecular weight (Mw). Increasing Mw increases the number of entanglement points in the polymer chains, thereby improving mechanical strength. Conversely, it is well-known that increasing Mw also increases ML, which is a viscosity. Therefore, to adjust the Mw / (ML×10000) ratio to a specified range, not only must Mw be controlled, but as mentioned above, it is also necessary to break the correlation between Mw and ML. Adjusting the molecular weight between the entanglement points of the polymer chains is effective in breaking this correlation.

[0176] Here, "molecular weight between entanglement points of polymer chains" is the minimum molecular weight required for polymer chains to entangle at one point, and "number of entanglement points of polymer chains" is the ratio of the molecular weight of the polymer compound to the molecular weight between entanglement points of the polymer chains, i.e. (molecular weight / molecular weight between entanglement points of polymer chains).

[0177] The molecular weight between entanglement points of a polymer chain is a value unique to that polymer, and it tends to depend on the proportions of the repeating units of the polymer chain (e.g., stereoconfiguration, straight or branched chains, single or double bonds, etc.). Therefore, Mw / (ML×10000) can be controlled within the aforementioned numerical range by adjusting the Mw of the polymer chain and the content of the prescribed structures that constitute the repeating units of the polymer chain.

[0178] In rubber-like polymers with different contents of a specified structure introduced into the polymer, the molecular weight between entanglement points of the polymer chains and the number of entanglement points of the polymer chains were measured. As a result, the following tendency was confirmed in the rubber-like polymer of this embodiment: compared with the structure of the above formula (1) as a repeating unit, the structure of the above formula (2) as a repeating unit is less prone to entanglement; and compared with the structure of the above formula (4) as a repeating unit, the structure of the above formula (3) as a repeating unit is less prone to entanglement.

[0179] Therefore, by increasing the content of the structure C2 of the above formula (2) or the content of the structure C3 of the above formula (3), and decreasing the content of the structure C1 of the above formula (1) or the content of the structure C4 of the above formula (4), the molecular weight between entanglement points can be increased. Even in rubbery polymers with large Mw, ML can be made less likely to increase. Therefore, based on these tendencies, Mw / (ML×10000) can be controlled within a specified range.

[0180] By controlling Mw / (ML×10000), processability can be improved, resulting in a soft rubber composition with uniformly dispersed fillers, few voids, and well-entangled rubber-like polymers. This rubber composition exhibits excellent tear strength.

[0181] Tear strength can be determined by the method described later.

[0182] The molecular weight between entanglement points of polymer chains can be determined by measuring the viscoelasticity of rubber-like polymers and then calculating the storage modulus of the rubber-like elastic region.

[0183] (Softener for rubber-like polymers)

[0184] The rubber-like polymer of this embodiment may contain a rubber softener as needed.

[0185] The content of the rubber softener is preferably 30% by mass or less.

[0186] In the rubber-like polymer of this embodiment, from the perspective of improving the processability when inorganic fillers are mixed in during tire manufacturing, the amount of rubber softener added is preferably 1 to 30% by mass.

[0187] When the molecular weight of the rubbery polymer is high, for example, when the weight average molecular weight is greater than 1 million, the amount of rubber softener added is preferably 15 to 30% by mass. On the other hand, from the perspective of expanding the degree of freedom in the mixing amount when preparing a rubber composition mixed with fillers, the amount of rubber softener added is preferably 1 to 15% by mass.

[0188] From the perspective of suppressing the deterioration of tires over the years, the content of rubber softener in the rubber composition using the rubber-like polymer of this embodiment is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0189] There are no particular limitations on the type of rubber softener used; examples include filler oils, low-molecular-weight rubbery polymers, and resins. However, filler oils are preferred from the perspectives of processability, productivity, and economy. Furthermore, from the perspective of the abrasion resistance of the rubber composition for tires, low-molecular-weight rubbery polymers that facilitate crosslinking are preferred.

[0190] As a method for adding a rubber softener to the rubber-like polymer of this embodiment, the following method is preferred, but not limited to: adding a rubber softener to a solution of the rubber-like polymer, mixing to prepare a polymer solution containing a rubber softener, and then desolvating it.

[0191] Preferred softeners include, but are not limited to, aromatic oils, cycloalkane oils, and paraffin oils.

[0192] Among these, from the perspectives of environmental safety, prevention of oil seepage, and wetland grip properties, alternative aromatic oils with a polycyclic aromatic (PCA) content of less than 3% by mass based on the IP346 method are preferred.

[0193] As alternative aromatic oils, examples include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0194] (Other additives)

[0195] The rubber-like polymer of this embodiment may contain various additives such as antioxidants as needed.

[0196] [Methods for manufacturing rubber-like polymers]

[0197] The method for manufacturing the rubber-like polymer according to this embodiment includes the following steps: copolymerizing a conjugated diene compound with an aromatic vinyl compound, and hydrogenating the resulting copolymer in such a manner that the hydrogenation rate is less than 90%.

[0198] In the method for manufacturing the rubber-like polymer of this embodiment, a conjugated diene compound and an aromatic vinyl compound are used as polymerizing monomers. By appropriately controlling the hydrogenation rate, the C1, C2, C3, and C4 can be controlled within the specified range of the rubber-like polymer of this embodiment.

[0199] Specifically, by adjusting the amount of 1,2-vinyl binding, 1,4-vinyl binding, and hydrogenation of the rubbery polymer before hydrogenation, C1, C2, C3, and C4 can be controlled in any proportion.

[0200] The 1,2-vinyl and 1,4-vinyl binding amounts of the rubbery polymer before hydrogenation can be controlled by adjusting the amount of polar compound added, as described later.

[0201] When C1 to C4 are controlled by the hydrogenation of the polymer, for example, when the amount of aromatic vinyl monomer unit is 15.0% by mass and the amount of 1,2-vinyl binding in the conjugated diene structure is 50 mol%, C1 to C4 can be controlled within the target range by making the hydrogenation rate 65%.

[0202] That is, the total value of C1 and C2 can be made to be in the range of 40 mol% to 60 mol%, C3 can be made to be in the range of 15 mol% to 60 mol%, and C4 can be controlled to be in the range of 2 mol% to 25 mol%.

[0203] Regarding the hydrogenation rate of the rubbery polymer in this embodiment, the hydrogenation rate of the structural units derived from the conjugated diene compound, such as butadiene, is preferably 30% or more, and preferably 90% or less. The lower limit is more preferably 50% or more, and further preferably 60% or more. The upper limit is more preferably 85% or less, and further preferably 80% or less.

[0204] In the rubber-like polymer of this embodiment, by making the hydrogenation rate of the structural units from the conjugated diene compound 30% or more, it tends to have excellent fracture strength and elongation at break of the sulfide.

[0205] By reducing the hydrogenation rate of structural units from conjugated diene compounds to below 90%, the crosslinking density after sulfidation increases, resulting in a tendency for the sulfide to exhibit excellent fracture strength and fuel-saving performance.

[0206] The hydrogenation rate of the rubber-like polymer in this embodiment can be controlled by adjusting the amount of hydrogen added relative to the structural units from the conjugated diene compound.

[0207] The temperature of the hydrogenation reaction is not particularly limited, but is preferably 60–105°C, more preferably 70–100°C.

[0208] Hydrogenation rate can be obtained through 1 The measurements were performed using H-NMR.

[0209] In the method for manufacturing the rubber-like polymer of this embodiment, anionic polymerization is preferably performed in the polymerization step from the perspective of easy control of molecular structure. In addition, at least part or most of the double bonds in the conjugated diene polymer obtained by polymerizing or copolymerizing conjugated diene monomers are hydrogenated (hydrogenated).

[0210] As a method for manufacturing the rubber-like polymer according to this embodiment, examples include those described in International Publication No. 96 / 05250, Japanese Patent Application Publication No. 2000-053706, International Publication No. 2003 / 085010, International Publication No. 2019 / 151126, International Publication No. 2019 / 151127, International Publication No. 2002 / 002663, and International Publication No. 2015 / 006179, which involve polymerizing a conjugated diene monomer using anionic polymerization under various additives and conditions, and then copolymerizing it with other monomers as needed before hydrogenation.

[0211] In the method for manufacturing the rubber-like polymer of this embodiment, the aromatic vinyl monomers, ethylene, α-olefins, conjugated diene monomers, and other monomers used during polymerization can be the same substances described in the various documents mentioned above.

[0212] The polymerization and hydrogenation processes described above can be carried out in either a batch or continuous manner.

[0213] (Polymerization process)

[0214] In the polymerization process, a polymerization initiator is used to polymerize conjugated diene compounds, aromatic vinyl compounds, and other monomers, if necessary.

[0215] Examples of polymerization initiators used in polymerization processes include organic monolithium compounds.

[0216] Examples of organic single-lithium compounds include, but are not limited to, low-molecular-weight compounds and soluble oligomers.

[0217] In addition, as organic single-lithium compounds, examples of compounds with carbon-lithium bonding, compounds with nitrogen-lithium bonding, and compounds with tin-lithium bonding can be cited as examples of the bonding forms between the organic group and the lithium.

[0218] The amount of the organic monolithium compound used as a polymerization initiator is preferably determined based on the structure of the rubber-like polymer of this embodiment and the molecular weight of the rubber-like polymer.

[0219] The amount of monomers, such as conjugated diene compounds, relative to the amount of polymerization initiator is related to the degree of polymerization of the rubber-like polymer. That is, it is related to the number-average molecular weight and / or weight-average molecular weight of the rubber-like polymer.

[0220] Therefore, to increase the molecular weight, the amount of polymerization initiator can be reduced, and to decrease the molecular weight, the amount of polymerization initiator can be increased.

[0221] From the perspective of using it as a method of introducing nitrogen atoms into a rubbery polymer, the organic monolithium compound used as a polymerization initiator is preferably an alkyl lithium compound having substituted amino groups, or a dialkylamino lithium compound.

[0222] In this case, a rubbery polymer with nitrogen atoms derived from amino groups at the polymerization initiation ends can be obtained.

[0223] Substituted amino groups are amino groups that do not have active hydrogen or whose active hydrogen is protected.

[0224] Examples of alkyl lithium compounds having an amino group that does not have active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium and 4-hexamethyleneiminobutyllithium.

[0225] Examples of alkyl lithium compounds with an amino group having a structure that protects active hydrogen include, but are not limited to, lithium 3-bistrimethylsilylaminopropyl and lithium 4-trimethylsilylmethylaminobutyl.

[0226] Examples of dialkylaminolithium include, but are not limited to, lithium dimethylaminolithium, lithium diethylaminolithium, lithium dipropylaminolithium, lithium dibutylaminolithium, lithium di-n-hexylaminolithium, lithium diheptylaminolithium, lithium diisopropylaminolithium, lithium dioctylaminolithium, lithium di-2-ethylhexylaminolithium, lithium didecylaminolithium, lithium ethylpropylaminolithium, lithium ethylbutylaminolithium, lithium ethylbenzylaminolithium, lithium methylphenethylaminolithium, lithium hexamethyleneiminolithium, lithium pyrrolidine, lithium piperidinyl, lithium heptamethyleneiminolithium, lithium morpholinyl, 1-lithiumazacyclooctane, 6-lithium-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithium-1,2,3,6-tetrahydropyridine.

[0227] These organolithium compounds with substituted amino groups can also be reacted in small amounts with monomers capable of polymerization, such as 1,3-butadiene, isoprene, styrene, etc., to be used as soluble oligomers of organolithium compounds.

[0228] From the perspectives of ease of industrial acquisition and ease of controlling the polymerization reaction, the organic monolithium compound used as the polymerization initiator is preferably an alkyl lithium compound. In this case, a rubbery polymer having an alkyl group at the polymerization initiation end can be obtained.

[0229] Examples of the aforementioned alkyl lithium compounds include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and lithium mesodephenylethylene.

[0230] From the perspectives of ease of industrial acquisition and ease of controlling the polymerization reaction, n-butyllithium and sec-butyllithium are preferred as alkyllithium compounds.

[0231] The aforementioned organolithium compounds can be used alone or in combination of two or more. They can also be used in combination with other organometallic compounds.

[0232] Other organometallic compounds mentioned above include, for example, alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0233] Examples of alkaline earth metal compounds include, but are not limited to, organomagnesia compounds, organocalcoagulant compounds, and organostrontium compounds. Additionally, alkaline earth metal alkoxides, sulfonates, carbonates, and amide compounds can also be mentioned.

[0234] Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium.

[0235] Other organometallic compounds include, for example, organoaluminum compounds.

[0236] Examples of polymerization reaction forms in polymerization processes include, but are not limited to, batch (also known as "partial") and continuous polymerization reaction forms.

[0237] In continuous reactors, one or more reactors connected in series can be used. Examples of continuous reactors include tank reactors and tubular reactors equipped with agitators.

[0238] In a continuous process, the monomer, inert solvent, and polymerization initiator are preferably continuously loaded into the reactor to obtain a polymer solution containing the polymer, and the polymer solution is continuously discharged.

[0239] For example, a tank reactor with a stirrer can be used for batch reactors.

[0240] In a batch process, it is preferable to fill the reactor with monomers, an inert solvent, and a polymerization initiator, and to add monomers continuously or intermittently during polymerization as needed, to obtain a polymer solution in the reactor, and to discharge the polymer solution after polymerization is completed.

[0241] In the method for manufacturing the rubbery polymer of this embodiment, in order to obtain a high proportion of polymers with active ends, a continuous process is preferred, in which the polymer can be continuously discharged and supplied to subsequent reactions in a short time.

[0242] The polymerization process of the rubber-like polymer in this embodiment is preferably carried out in an inert solvent.

[0243] Examples of inert solvents include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons.

[0244] Specific hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and hydrocarbons composed of mixtures thereof.

[0245] Treating propadiene and acetylene, which are impurities, with organometallic compounds before the polymerization process tends to yield rubbery polymers with high concentrations of active ends, and also tends to yield rubbery polymers with high modification rates after the modification process, and is therefore preferred.

[0246] Polar compounds can be added during the polymerization process. This enables the random copolymerization of aromatic vinyl compounds and conjugated diene compounds. Furthermore, polar compounds tend to be used as vinylizing agents to control the microstructure of the conjugated diene portion. They also tend to exhibit effects in promoting the polymerization reaction.

[0247] Examples of polar compounds include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-tetrahydrofuranyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinyl ethane, trimethylamine, triethylamine, pyridine, and quinine ring; alkali metal alkoxides such as potassium tert-pentanoxide, potassium tert-butoxide, sodium tert-butoxide, and sodium pentanoxide; and phosphine compounds such as triphenylphosphine.

[0248] These polar compounds can be used alone or in combination of two or more.

[0249] There is no particular limitation on the amount of polar compound used, and it can be selected according to the purpose, etc. It is preferably 0.01 moles to 10 moles relative to 1 mole of polymerization initiator.

[0250] By adding a polar compound in the range of 0.01 mol to 10 mol relative to 1 mol of the polymerization initiator, the amount of 1,2-bound compounds in the rubbery polymer increases, while the amount of 1,4-bound compounds decreases. This results in a tendency for an increase in the amount of C1+C2 and a decrease in the amount of C3 and C4 in the rubbery polymer.

[0251] Such polar compounds (vinylating agents) can be used as modifiers of the microstructure of the conjugated diene portion of rubbery polymers, depending on the desired amount of 1,2-vinyl binding. Most polar compounds also exhibit effective randomization effects in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to be used as modifiers of the distribution of aromatic vinyl compounds and the amount of styrene blocks.

[0252] As a method for randomization in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, one example is the method described in Japanese Patent Application Publication No. 59-140211, which involves initiating a copolymerization reaction using the total amount of styrene and a portion of 1,3-butadiene, and intermittently adding the remaining 1,3-butadiene during the copolymerization reaction.

[0253] The polymerization temperature in the polymerization process is preferably the temperature for active anionic polymerization. From a productivity perspective, it is more preferably above 0°C, further preferably below 120°C, and even more preferably above 50°C and below 100°C. By keeping the polymerization temperature within such a range, there is a tendency to sufficiently ensure the amount of modifier reacting with respect to the active end after polymerization.

[0254] (Branching process)

[0255] In the method for manufacturing the rubber-like polymer of this embodiment, a further step of adjusting the branching degree of the rubber-like polymer can be implemented.

[0256] As a method to increase the branching degree of rubbery polymers, one example is the use of a branching agent, a compound derived from a vinyl monomer containing alkoxysilyl and / or halosilyl groups.

[0257] By adding a branching agent during the polymerization process, followed by the addition of monomers to continue the polymerization reaction, the polymer chains branched at the branching points can be lengthened. Furthermore, modifiers, coupling agents, etc., can be added subsequently to implement a modification process.

[0258] (Modification process)

[0259] For the active ends of the polymer obtained by the above polymerization process and, if necessary, the branching process using the specified branching agent, the above coupling agent or a modifier having nitrogen-containing atomic groups is used to carry out the modification process.

[0260] (Deactivating agent, neutralizing agent)

[0261] In the method for manufacturing the rubber-like polymer of this embodiment, after the modification process, deactivating agents, neutralizing agents, etc., can be added to the polymer solution as needed.

[0262] Examples of deactivating agents include, but are not limited to, water; alcohols such as methanol, ethanol, and isopropanol; and so on.

[0263] Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, neodecanoic acid (a mixture of multi-branched carboxylic acids with 9 to 11 carbon atoms, with 10 as the central element); aqueous solutions of inorganic acids; and carbon dioxide.

[0264] (Hydrogenation process)

[0265] The method for manufacturing the rubber-like polymer of this embodiment includes a hydrogenation step in which the hydrogenation rate is 90% or less.

[0266] The hydrogenation rate can be controlled, for example, by adjusting the amount of hydrogen during hydrogenation, and the hydrogenation rate can be controlled, for example, by adjusting the amount of hydrogen added, pressure, and temperature. The hydrogenation rate of rubbery polymers can be measured using proton nuclear magnetic resonance (NMR). 1 The determination was performed using the H-NMR method.

[0267] (Addition of stabilizers for rubber)

[0268] In the method for manufacturing the rubber-like polymer of this embodiment, from the perspective of preventing gel formation after polymerization and improving stability during processing, it is preferable to add a rubber stabilizer.

[0269] As a stabilizer for rubber, known substances can be used, but are not limited to, such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, 2-methyl-4,6-bis[(octylthio)methyl]phenol and other antioxidants.

[0270] (Desolventization process)

[0271] In the method for manufacturing the rubbery polymer of this embodiment, a known method can be used as the method for removing the obtained polymer from the polymer solution. This method is not particularly limited; examples include: separating the solvent by stripping or the like, filtering the polymer, and further dehydrating and drying it to obtain the polymer; concentrating the polymer using a flash evaporator and then performing devolatilization using an exhaust extruder or the like; and directly performing devolatilization using a rotary dryer or the like.

[0272] [Rubber Composition]

[0273] The rubber composition of this embodiment contains the rubber-like polymer and crosslinking agent described in this embodiment. It is preferred that the crosslinking agent is present in an amount of 0.1 to 20 parts by mass relative to 100 parts by mass of the rubber component containing the rubber-like polymer of this embodiment.

[0274] It should be noted that the rubber component includes the rubber-like polymer constituting the composition of this embodiment, as well as various other known rubbers that can constitute the rubber composition of this embodiment.

[0275] There are no particular restrictions on other types of rubber; they can be selected appropriately according to the purpose. Examples include styrene-butadiene rubber (emulsion polymerization type, solution polymerization type), natural rubber, polyisoprene, butadiene rubber (high cis polybutadiene, low cis polybutadiene, syndiotactic-1,2-polybutadiene), nitrile rubber (NBR), chloroprene rubber, ethylene-alpha-olefin copolymer rubbers such as ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), butyl rubber, polysulfide rubber, silicone rubber, fluororubber, and urethane rubber.

[0276] These other rubbers can be used alone or in combination of two or more. As a mixing method, they can be mixed in a dry state after the polymerization of the rubber-like polymer, or they can be mixed in a solution state during the polymerization of the rubber-like polymer.

[0277] There are no particular limitations on the crosslinking agents mentioned above; they can be selected appropriately according to the purpose. Examples include sulfur-based crosslinking agents, organic peroxide-based crosslinking agents, inorganic crosslinking agents, polyamine crosslinking agents, resin crosslinking agents, sulfur-containing compound-based crosslinking agents, and oxime-nitrosamine-based crosslinking agents. One of these agents can be used alone, or two or more can be used in combination.

[0278] It should be noted that when the rubber composition of this embodiment is used for tire applications, sulfur-based crosslinking agents (vulcanizing agents) are more preferred among these crosslinking agents. In particular, sulfur is even more preferred.

[0279] The content of the crosslinking agent in the rubber composition of this embodiment is preferably 0.1 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the rubber component. From the perspective of high tensile strength and high crosslinking speed, it is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.5 parts by mass or more. On the other hand, from the perspective of suppressing uneven crosslinking and high tensile strength, it is preferably 20 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0280] The rubber composition of this embodiment may contain a vulcanizing agent, and may also be further combined with a vulcanization accelerator.

[0281] Examples of such vulcanization accelerators include, but are not limited to, compounds such as guanidine-based compounds, aldehyde-amine-based compounds, aldehyde-amine-based compounds, thiazole-based compounds, sulfenamide-based compounds, thiourea-based compounds, thiuram-based compounds, dithiocarbamate-based compounds, and xanthate-based compounds.

[0282] In addition, the rubber composition of this embodiment may contain various additives such as other softeners, fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants besides those mentioned above.

[0283] Other known plasticizers can be used as alternatives.

[0284] Other fillers that can be cited include, but are not limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.

[0285] As a heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant, known materials can be used respectively.

[0286] (sulfides)

[0287] The rubber composition of this embodiment can be suitably used as a vulcanizate.

[0288] For example, a sulfide can be obtained by mixing the rubber-like polymer of this embodiment with an inorganic filler such as silica or carbon black, a rubber component other than the rubber-like polymer of this embodiment, a silane coupling agent, a rubber softener, a wax, a vulcanizing agent, a vulcanization accelerator, and a vulcanization aid to form a rubber composition, and then heating and vulcanizing it.

[0289] There are no particular limitations on the method for identifying the types and proportions of rubber components contained in the rubber composition of this embodiment; for example, identification can be performed using NMR.

[0290] For example, as described in the existing report (JSR TECHNICAL REVIEW No. 126 / 2019), it can be achieved by using solid... 13 C-NMR was used to quantitatively calculate the proportions of styrene units, 1,2-vinyl binding, 1,4-vinyl binding, 1,4-cis binding, and isoprene units in the rubber composition.

[0291] (Silicon oxide)

[0292] The rubber composition of this embodiment may contain silicon dioxide.

[0293] Regarding the silica content in the rubber composition, it is preferably 30 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the rubber component containing the rubber-like polymer of this embodiment.

[0294] From the perspective of improving the grip and handling stability when the rubber composition of this embodiment is used in tires, the content of silica is preferably 60 parts by mass or more, more preferably 65 parts by mass or more, and even more preferably 75 parts by mass or more relative to 100 parts by mass of the rubber component. Furthermore, from the perspective of improving fuel efficiency when used in tires, the content is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less.

[0295] Silicon oxide is not particularly limited and any known material can be used. Solid particles containing SiO2 or Si3Al as structural units are preferred, and solid particles containing SiO2 or Si3Al as the main structural unit are more preferred. Here, "main component" refers to a component that contains 50% or more by mass, preferably 70% or more by mass, and more preferably 80% or more by mass in silicon oxide.

[0296] Examples of silica include, but are not limited to, inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber.

[0297] Commercially available products made of silicon dioxide include, for example, the product manufactured by Evonik Degussa under the trade name "Ultrasil 7000GR".

[0298] In addition, as silicon oxide, a silicon oxide-based inorganic filler with a hydrophobic surface can be used, and the silicon oxide-based inorganic filler can also be used in combination with inorganic fillers other than silicon oxide.

[0299] Among these, silica and glass fiber are preferred in terms of strength and wear resistance, with silica being more preferred.

[0300] Examples of silica include dry silica, wet silica, and synthetic silicate silica. Among these, wet silica is preferred in terms of its superior balance between improved destructive properties and excellent wet grip properties.

[0301] In the rubber composition of this embodiment, from the perspective of obtaining practically good abrasion resistance and destructive properties, when a silica-based inorganic filler is included, the nitrogen adsorption specific surface area of ​​the silica-based inorganic filler, as determined by the BET adsorption method, is preferably 100 m². 2 / g or more 300m 2 / g or less, more preferably 170m 2 / g or more 250m 2 / g or less.

[0302] Additionally, depending on the need, smaller specific surface areas (e.g., specific surface area less than 200m²) can be selected. 2 / g of silica-based inorganic filler) and a large specific surface area (e.g., 200m²) 2 The combination of silica-based inorganic fillers (at least / g) allows for a high degree of balance between excellent wear resistance and destructive properties and fuel-saving characteristics.

[0303] (Silane coupling agent)

[0304] The rubber composition of this embodiment may include a silane coupling agent from the perspective of improving the dispersibility of the filler and increasing the tensile strength of the crosslinked body.

[0305] Silane coupling agents have the function of making the interaction between rubber components and inorganic fillers more intense. They have groups that have affinity or binding with the rubber components and fillers, respectively, and are preferably compounds that have a sulfur-binding moiety and an alkoxysilyl or silanol moiety in one molecule.

[0306] Examples of such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide, 3-octanoylthiopropyltriethoxysilane, condensates of 3-octanoylthiopropyltriethoxysilane and [(triethoxysilyl)-propyl]thiol, mercaptosilanes having at least one thiol functional group (-SH), and silanes supported with at least one masking mercapto group.

[0307] Relative to 100 parts by weight of the rubber component comprising the rubber-like polymer of this embodiment, the content of the silane coupling agent in the rubber composition of this embodiment is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and even more preferably 1.0 parts by weight or more. Furthermore, it is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 15 parts by weight or less.

[0308] When the content of the silane coupling agent is within the above range, there is a tendency to make the above-mentioned additive effects brought about by the silane coupling agent more significant.

[0309] (Carbon black)

[0310] The rubber composition of this embodiment preferably contains 100 parts by weight of a rubber component comprising the rubber-like polymer of this embodiment, and 1 to 100 parts by weight of carbon black.

[0311] There are no particular limitations on the type of carbon black used; for example, various grades of carbon black such as SRF, FEF, HAF, ISAF, and SAF can be used. Among these, considering extrusion moldability and rolling resistance characteristics, a nitrogen adsorption specific surface area of ​​50 m² is preferred. 2 Carbon black with an oil absorption of 80 mL / 100 g or more and dibutyl phthalate (DBP) of 80 mL / 100 g or more.

[0312] From the perspective of improving wear resistance, the carbon black content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of rubber component. Furthermore, from the perspective of improving fuel efficiency, the carbon black content is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less.

[0313] (Softener)

[0314] The rubber composition of this embodiment preferably contains 100 parts by weight of a rubber component comprising the rubber-like polymer of this embodiment, and 1 to 60 parts by weight of a softener.

[0315] There are no particular limitations on the type of softener; examples include filler oils, low-molecular-weight rubbery polymers, and resins. However, filler oils are preferred from the perspectives of processability, productivity, and economy. Furthermore, from the perspective of the abrasion resistance of the rubber composition for tires, low-molecular-weight rubbery polymers that facilitate cross-linking are preferred.

[0316] Preferred softeners include, but are not limited to, aromatic oils, cycloalkane oils, and paraffin oils.

[0317] Among these, from the perspectives of environmental safety, prevention of oil seepage, and wetland grip properties, alternative aromatic oils with a polycyclic aromatic (PCA) content of less than 3% by mass based on the IP346 method are preferred.

[0318] As alternative aromatic oils, examples include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0319] In the rubber composition of this embodiment, from the perspective of processability, the content of the softener is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the rubber component. Furthermore, from the perspective of abrasion resistance, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less.

[0320] (Mixing method of rubber composition)

[0321] Regarding methods for mixing rubber components, crosslinking agents, silica, carbon black or other fillers, silane coupling agents, softeners, and other additives that include the rubber-like polymer of this embodiment and other rubbers, examples include, but are not limited to, melt mixing methods using common mixers such as open mills, Banbury mixers, kneaders, single-screw extruders, twin-screw extruders, and multi-screw extruders; and methods for dissolving and mixing the components and then heating to remove the solvent.

[0322] Among these methods, melt mixing using rollers, Banbury mixers, kneaders, and extruders is preferred in terms of productivity and good mixability. Alternatively, methods that involve mixing the rubber components with fillers, silane coupling agents, and additives in a single step, or methods that involve mixing in multiple stages, can also be used.

[0323] [use]

[0324] The rubber composition of this embodiment can be preferably used as a crosslinking rubber composition in tire parts, automotive interior and exterior materials, shock-absorbing rubber, belts, footwear, foams, and various industrial products.

[0325] Of these, they are preferred for tire components.

[0326] As tire components, tires can be categorized into various types such as fuel-efficient tires, all-season tires, high-performance tires, snow tires, and studless anti-skid tires, which include tire tread, tire carcass, sidewall, and bead.

[0327] In particular, the rubber composition of this embodiment has an excellent balance of wear resistance, fuel efficiency, wet grip and snow performance after being made into a vulcanizate, and can be used as a fuel-efficient tire or high-performance tire, or as a tire tread for snow tires.

[0328] As a method for manufacturing tires, known methods can be used. For example, at least one type of tire carcass layer, belt layer, tread layer, or other components commonly used in tire manufacturing, selected from the group consisting of an uncured cross-linked rubber composition and tire cord fabric, is sequentially overlapped and glued onto a tire forming drum. The drum is then removed to form a green tire. Next, the green tire is heated and vulcanized using conventional methods, thereby producing the desired tire (e.g., a pneumatic tire).

[0329] Example

[0330] The following specific embodiments and comparative examples are provided to further illustrate this implementation method in detail, but this implementation method is not limited to any of the following embodiments and comparative examples.

[0331] The various physical properties in the examples and comparative examples were determined by the methods shown below.

[0332] (Microstructure of the butadiene portion of the rubbery polymer before hydrogenation (1,2-vinyl binding content))

[0333] 50 mg of the unhydrogenated rubbery polymer was dissolved in 10 mL of carbon disulfide to prepare the test sample.

[0334] Using a solution dish, at a depth of 600–1000 cm. -1 The infrared spectrum was measured within a specified range. The microstructure of the butadiene moiety, i.e. the 1,2-vinyl binding amount (mol%), was determined from the absorbance at a specified wavenumber according to the calculation formula of the Hampton method (RR Hampton, Analytical Chemistry 21, 923 (1949)). (Measurement device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by Japan Spectrophotometer Co., Ltd.).

[0335] (Weight-average molecular weight of rubber-like polymers)

[0336] Using a GPC assay apparatus with three columns packed with polystyrene-based gel, chromatograms were measured, and the weight-average molecular weight of the rubbery polymer was determined based on a calibration curve obtained using standard polystyrene.

[0337] The eluent used was THF (tetrahydrofuran) containing 5 mmol / L triethylamine.

[0338] Regarding the column, the following products are used: the protective column is manufactured by Tosoh under the trade name "TSKguardcolumn SuperH-H", and the column is manufactured by Tosoh under the trade names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000".

[0339] An RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) was used under the conditions of oven temperature 40°C and THF flow rate 0.6 mL / min.

[0340] Dissolve 10 mg of the sample to be measured in 20 mL of THF to prepare the test solution. Inject 20 μL of the test solution into the GPC measuring device for measurement.

[0341] (Modification rate of rubber-like polymer)

[0342] The modification rate of rubbery polymers was determined by column adsorption GPC as follows. The determination was performed using the characteristic of nitrogen-containing functional groups in rubbery polymers being adsorbed onto the column.

[0343] The amount of adsorption on the silica column is determined by the difference between the chromatogram obtained by measuring the sample solution containing the sample and the low molecular weight internal standard polystyrene using a polystyrene column and the chromatogram obtained by measuring the sample solution using a silica column, and the modification rate is calculated.

[0344] Specifically, as shown below.

[0345] <Preparation of Sample Solution>:

[0346] Dissolve 10 mg of the sample and 5 mg of standard polystyrene in 20 mL of THF to prepare the sample solution.

[0347] Using THF containing 5 mmol / L triethylamine as the eluent, 20 μL of the sample solution was injected into the apparatus for determination. For the columns, the following were used: guard column: "TSKguardcolumn SuperH-H" (Tosoh Corporation); columns: "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" (Tosoh Corporation). The determination was performed using an RI detector (Tosoh Corporation HLC8020) at a column oven temperature of 40°C and a THF flow rate of 0.6 mL / min, yielding the chromatogram.

[0348] <GPC determination conditions using silica-based columns>:

[0349] Using the Tosoh HLC-8320GPC, a product manufactured by Tosoh Corporation, and THF as the eluent, 50 μL of the sample solution was injected into the device. Chromatograms were obtained using an RI detector at a column oven temperature of 40°C and a THF flow rate of 0.5 mL / min. For the columns, the product names "Zorbax PSM-1000S," "PSM-300S," and "PSM-60S" were used, with a product name "DIOL 4.6 × 12.5 mm 5 micron" connected as a guard column.

[0350] <Method for calculating modification rate>:

[0351] Set the peak area of ​​the chromatogram obtained using a polystyrene column to 100, set the peak area of ​​the sample to P1, set the peak area of ​​the standard polystyrene to P2, set the peak area of ​​the chromatogram obtained using a silica column to 100, set the peak area of ​​the sample to P3, set the peak area of ​​the standard polystyrene to P4, and calculate the modification rate (%) using the following formula.

[0352] Modification rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100

[0353] (Where, P1 + P2 = P3 + P4 = 100)

[0354] (Silicon content of rubber-like polymers)

[0355] The silicon content of the rubber-like polymer was determined using an ICP mass spectrometer (Agilent Technologies Agilnet 7700s).

[0356] (Hydrogenation rate of rubber-like polymers and C1, C2, C3, C4, S)

[0357] A large amount of methanol is added to the reaction solution of the hydrogenated rubbery polymer, thereby causing the unhydrogenated rubbery polymer and the hydrogenated rubbery polymer to precipitate for recovery.

[0358] Next, the hydrogenated rubber-like polymer was extracted with acetone and then vacuum dried.

[0359] Use it as 1 The hydrogenation rate, the content of the structures represented by formulas (1) to (4) C1, C2, C3, C4, and the content of aromatic vinyl monomer units S in the samples were determined by H-NMR.

[0360] 1 The conditions for H-NMR measurement are as follows.

[0361] <Measurement Conditions>

[0362] Measuring instrument: JNM-LA400 (manufactured by JEOL)

[0363] Solvent: Deuterated chloroform

[0364] Test samples: Extracts of the polymer before and after hydrogenation.

[0365] Sample concentration: 50 mg / mL

[0366] Observation frequency: 400MHz

[0367] Chemical shift reference: TMS (tetramethylsilane)

[0368] Pulse delay: 2.904 seconds

[0369] Number of scans: 64

[0370] Pulse width: 45°

[0371] Measurement temperature: 26℃

[0372] (Styrene content of rubber-like polymer (mass%))

[0373] A rubbery polymer was used as the sample. 100 mg of the sample was dissolved in chloroform and diluted to 100 mL to prepare the test sample. The amount of styrene in the sample (mass%) was determined by the amount of absorbance at the ultraviolet absorption wavelength (around 254 nm) caused by the phenyl group of styrene (measuring apparatus: Shimadzu UV-2450 spectrophotometer).

[0374] (Nitrogen content of rubber-like polymers)

[0375] The nitrogen content of the rubber-like polymer sample was determined using a trace nitrogen analyzer (Nitto Seiko Analytech TN-2100H).

[0376] (Mounney viscosity (ML) of rubber-like polymers)

[0377] The rubbery polymer was used as a sample and the determination was performed according to the method specified in ISO 289.

[0378] In Table 1, the Mooney viscosity value measured at 100℃ will be denoted as ML.

[0379] Additionally, Mw / (ML×10000) was calculated.

[0380] [Manufacturing of rubber-like polymers]

[0381] (Preparation of hydrogenation catalyst)

[0382] The hydrogenation catalyst used in the preparation of the rubber-like polymer in the manufacturing example described below is prepared by the method of manufacturing example α described below.

[0383] <Manufacturing Example α>

[0384] One liter of dried and purified cyclohexane was added to a reaction vessel purged with nitrogen, along with 100 mmol of bis(n5-cyclopentadiene)titanium dichloride. While stirring thoroughly, a solution of n-hexane containing 200 mmol of trimethylaluminum was added. The reaction was carried out at room temperature for about 3 days to obtain the hydrogenation catalyst (TC-1).

[0385] (Polymerization of rubber-like polymers)

[0386] <(Example 1) Rubber-like polymer A1>

[0387] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 16.6g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0388] Next, 3.7 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0389] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0390] After the temperature rise in the reactor due to the heat of reaction from the added butadiene subsided, 3.8 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added to the reactor as a modifier, and the mixture was stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0391] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the unhydrogenated rubbery polymer solution at a concentration of 60 ppm based on Ti per 100 parts by mass of the unhydrogenated rubbery polymer, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A1.

[0392] The hydrogenation rate of the obtained rubbery polymer A1 was 68 mol%.

[0393] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added to the solution of the obtained rubbery polymer as antioxidants.

[0394] The analytical values ​​of the rubbery polymer A1 are shown in Table 1.

[0395] <(Example 2) Rubber-like polymer A2>

[0396] Except for the amount of hydrogenation, rubbery polymer A2 was obtained under the same manufacturing conditions as in Example 1.

[0397] The analytical values ​​of the rubbery polymer A2 are shown in Table 1.

[0398] <(Example 3) Rubber-like polymer A3>

[0399] The amount of the polar compound 2,2-bis(2-tetrahydrofuranyl)propane was changed to 7.5 g, and the amount of hydrogenation was also changed. Rubber-like polymer A3 was obtained under the same conditions as in Example 1.

[0400] The analytical values ​​of the rubbery polymer A3 are shown in Table 1.

[0401] <(Example 4) Rubber-like polymer A4>

[0402] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 2,748g of 1,3-butadiene, 731.0g of styrene, 25,800g of cyclohexane, and 15.2g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0403] Next, 3.7 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0404] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 820.9 g of supplementary 1,3-butadiene is added.

[0405] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 3.8 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0406] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A4.

[0407] The hydrogenation rate of the obtained rubbery polymer A4 was 68 mol%.

[0408] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A4.

[0409] The analytical values ​​of the rubbery polymer A4 are shown in Table 1.

[0410] <(Example 5) Rubber-like polymer A5>

[0411] Except for the amount of hydrogenation, rubbery polymer A5 was obtained under the same manufacturing conditions as in Example 4.

[0412] The analytical values ​​of the rubbery polymer A5 are shown in Table 1.

[0413] <(Example 6) Rubber-like polymer A6>

[0414] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 2,483g of 1,3-butadiene, 1,075.0g of styrene, 25,800g of cyclohexane, and 15.2g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0415] Next, 3.7 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0416] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 741.8 g of supplementary 1,3-butadiene is added.

[0417] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 3.8 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0418] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A6.

[0419] The hydrogenation rate of the obtained rubbery polymer A6 was 72 mol%.

[0420] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A6.

[0421] The analytical values ​​of the rubbery polymer A6 are shown in Table 1.

[0422] <(Example 7) Rubber-like polymer A7>

[0423] Except for the amount of hydrogenation, rubbery polymer A7 was obtained under the same manufacturing conditions as in Example 6.

[0424] The analytical values ​​of the rubbery polymer A7 are shown in Table 1.

[0425] <(Example 8) Rubber-like polymer A8>

[0426] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 14.1g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0427] Next, 3.1 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0428] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0429] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 3.3 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0430] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A8.

[0431] The hydrogenation rate of the obtained rubbery polymer A8 was 68 mol%.

[0432] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A8.

[0433] The analytical values ​​of the rubbery polymer A8 are shown in Table 1.

[0434] <(Example 9) Rubber-like polymer A9>

[0435] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 20.5g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0436] Next, 4.6 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0437] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0438] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 4.9 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0439] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A9.

[0440] The hydrogenation rate of the obtained rubbery polymer A9 was 68 mol%.

[0441] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A9.

[0442] The analytical values ​​of the rubbery polymer A9 are shown in Table 1.

[0443] <(Example 10) Rubber-like polymer A10>

[0444] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 11.0g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0445] Next, 2.4 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0446] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0447] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 2.6 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0448] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain the rubbery polymer A10.

[0449] The hydrogenation rate of the obtained rubbery polymer A10 was 69 mol%.

[0450] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A10.

[0451] The analytical values ​​of the rubbery polymer A10 are shown in Table 1.

[0452] <(Example 11) Rubber-like polymer A11>

[0453] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 12.9g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0454] Next, 2.9 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0455] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0456] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 2.1 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0457] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain the rubbery polymer A11.

[0458] The hydrogenation rate of the obtained rubbery polymer A11 was 68 mol%.

[0459] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A11.

[0460] The analytical values ​​of the rubbery polymer A11 are shown in Table 1.

[0461] <(Example 12) Rubber-like polymer A12>

[0462] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 9.5g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0463] Next, 2.1 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0464] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0465] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 2.2 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added to the reactor as a modifier, and the mixture was stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0466] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above <Manufacturing Example α> was added to the unhydrogenated rubbery polymer solution at a concentration of 60 ppm based on Ti per 100 parts by mass of the unhydrogenated rubbery polymer. The hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer A12.

[0467] The hydrogenation rate of the obtained rubbery polymer A12 was 69 mol%.

[0468] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer A12.

[0469] The analytical values ​​of the rubbery polymer A12 are shown in Table 1.

[0470] <(Comparative Example 1) Rubber-like polymer B1>

[0471] Except for the amount of hydrogenation, rubbery polymer B1 was obtained under the same manufacturing conditions as in Example 1.

[0472] The analytical values ​​of the rubbery polymer B1 are shown in Table 2.

[0473] <(Comparative Example 2) Rubber-like polymer B2>

[0474] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,112g of 1,3-butadiene, 258.0g of styrene, 25,800g of cyclohexane, and 16.7g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0475] Next, 3.8 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0476] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 929.7 g of supplementary 1,3-butadiene is added.

[0477] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 4.0 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0478] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the unhydrogenated rubbery polymer solution at a concentration of 60 ppm based on Ti per 100 parts by mass of the unhydrogenated rubbery polymer, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure 0.8 MPa and average temperature 85°C to obtain rubbery polymer B2.

[0479] The hydrogenation rate of the obtained rubbery polymer B2 was 68 mol%.

[0480] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer B2.

[0481] The analytical values ​​of the rubbery polymer B2 are shown in Table 2.

[0482] <(Comparative Example 3) Rubber-like polymer B3>

[0483] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 2,318g of 1,3-butadiene, 1,290.0g of styrene, 25,800g of cyclohexane, and 8.7g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0484] Next, 3.1 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0485] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 692.3 g of supplementary 1,3-butadiene is added.

[0486] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 3.3 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0487] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer B3.

[0488] The hydrogenation rate of the obtained rubbery polymer B3 was 55 mol%.

[0489] The solution of the obtained rubbery polymer B3 was supplemented with 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate as an antioxidant and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol.

[0490] The analytical values ​​of the rubbery polymer B3 are shown in Table 2.

[0491] <(Comparative Example 4) Rubber-like polymer B4>

[0492] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 4.1g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0493] Next, 3.7 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0494] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0495] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 4.0 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added as a modifier and stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0496] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the unhydrogenated rubbery polymer solution at a concentration of 60 ppm based on Ti per 100 parts by mass of the unhydrogenated rubbery polymer, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure 0.8 MPa and average temperature 85°C to obtain rubbery polymer B4.

[0497] The hydrogenation rate of the obtained rubbery polymer B4 was 37 mol%.

[0498] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to a solution of the obtained rubbery polymer B4.

[0499] The analytical values ​​of the rubbery polymer B4 are shown in Table 2.

[0500] <(Comparative Example 5) Rubber-like polymer B5>

[0501] The amount of the polar compound 2,2-bis(2-tetrahydrofuranyl)propane was changed to 23.1 g, the amount of the polymerization initiator n-butyllithium was changed to 5.1 g, the amount of the modifier was changed to 5.5 g, and the amount of hydrogenation was changed. Apart from these changes, the rubbery polymer B5 was obtained in the same manner as in Example 9.

[0502] The analytical values ​​of the rubbery polymer B5 are shown in Table 2.

[0503] <(Comparative Example 6) Rubber-like polymer B6>

[0504] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 3,046g of 1,3-butadiene, 344.0g of styrene, 25,800g of cyclohexane, and 16.6g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0505] Next, 3.7 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0506] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 909.9 g of supplementary 1,3-butadiene is added.

[0507] After the temperature rise in the reactor due to the heat of reaction from the added 1,3-butadiene submerged, 2.2 g of silicon tetrachloride as a coupling agent was added to the reactor, and the mixture was stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the unhydrogenated rubbery polymer.

[0508] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer B6.

[0509] The hydrogenation rate of the obtained rubbery polymer B6 was 68 mol%.

[0510] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer B6.

[0511] The analytical values ​​of the rubbery polymer B6 are shown in Table 2.

[0512] <(Comparative Example 7) Rubber-like polymer B7>

[0513] Except for the amount of hydrogenation, rubbery polymer B7 was obtained under the same manufacturing conditions as in Example 1.

[0514] The analytical values ​​of the rubbery polymer B7 are shown in Table 2.

[0515] <(Comparative Example 8) Rubber-like polymer B8>

[0516] A 43L autoclave equipped with a stirrer and jacket, and capable of temperature control, was used as the reactor. 2,318g of 1,3-butadiene, 1,290g of styrene, 25,800g of cyclohexane, and 9.5g of 2,2-bis(2-tetrahydrofuranyl)propane (a polar compound) were added to the reactor beforehand, and the reactor temperature was maintained at 42°C.

[0517] Next, 3.0 g of n-butyllithium, which serves as a polymerization initiator, is supplied to the reactor.

[0518] After the polymerization reaction begins, the temperature inside the reactor starts to rise due to the exothermic reaction caused by polymerization. When the temperature rise is no longer confirmed, 692.3 g of supplementary 1,3-butadiene is added.

[0519] After the temperature rise in the reactor caused by the heat of reaction of the added 1,3-butadiene submerged, 3.2 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-nitrosilane was added to the reactor as a modifier, and the mixture was stirred for 5 minutes. A portion of the polymerization solution was then extracted and dried to obtain the rubbery polymer before hydrogenation.

[0520] Subsequently, the hydrogenation catalyst (TC-1) prepared in the above-mentioned <Manufacturing Example α> was added to the solution of the rubbery polymer before hydrogenation at a concentration of 60 ppm based on Ti per 100 parts by mass of the rubbery polymer before hydrogenation, and the hydrogenation reaction was carried out for 50 minutes under the conditions of hydrogen pressure of 0.8 MPa and average temperature of 85°C to obtain rubbery polymer B8.

[0521] The hydrogenation rate of the obtained rubbery polymer B8 was 90 mol%.

[0522] 12.6 g of n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)o-cresol were added as antioxidants to the solution of the obtained rubbery polymer B8.

[0523] The analytical values ​​of the rubbery polymer B8 are shown in Table 2.

[0524]

[0525]

[0526] [Examples 13-36], [Comparative Examples 9-16], [Reference Example]

[0527] (Preparation and property evaluation of crosslinking rubber compositions)

[0528] Using rubber-like polymers A1 to A12 obtained in Examples 1 to 12 as shown in Tables 1 and 2, rubber-like polymers B1 to B8 obtained in Comparative Examples 1 to 8, and Y031 manufactured by Asahi Kasei Corporation (containing 25% by mass of styrene and 58 mol% of 1,2-vinyl binding content in butadiene) as raw material rubbers, a crosslinking rubber composition containing each raw material rubber was obtained according to the proportions shown below.

[0529] The mixing conditions are as follows.

[0530] (Mixing conditions)

[0531] The amount of each compounding agent added in Tables 3 to 5 is expressed as parts by mass relative to 100 parts by mass of the rubber component that does not contain rubber softener.

[0532] • Rubber compositions A1~A12, B1~B8, Y031: 100.0 parts by weight

[0533] •Silica 1: VN3 (N2SA: 175m) manufactured by Evonik Degussa 2 / g)

[0534] •Silica 2: 115GR (N2SA: 115m) manufactured by Solvay Japan Co., Ltd. 2 / g)

[0535] • Silicon oxide 3: 9000GR (N2SA: 235m) manufactured by Evonik Degussa 2 / g)

[0536] • Carbon 1: Diablack N339 (N2SA: 96m) manufactured by Mitsubishi Chemical Corporation 2 / g, DBP absorption value: 124mL / 100g)

[0537] • Carbon-2: Show Black N330 (N2SA: 75m) manufactured by Cabot Japan Co., Ltd. 2 / g)

[0538] • Softener 1: DIANA Process AH-24 (fragrant oil) manufactured by Idemitsu Kosan Co., Ltd.

[0539] • Softener 2: PS-32 (mineral oil) manufactured by Idemitsu Kosan Co., Ltd.

[0540] • Softener 3: SYLVARES SA85 (α-methylstyrene resin (copolymer of α-methylstyrene and styrene), manufactured by Arizona Chemical Company, softening point: 85°C)

[0541] • Softener 4: NOVARES C100 (benzofuran indene resin, softening point: 95-105℃) manufactured by Rutgers Chemicals

[0542] • Softener 5: Kuraprene LIR30 (liquid IR, weight average molecular weight: 29000) manufactured by KURARAY.

[0543] • Softener 6: Sylvatraxx 4150 (polyterpene resin, softening point: 150℃) manufactured by KRATON

[0544] • Softener 7: RICON100 manufactured by Sartomer (liquid SBR, styrene content: 20% by mass, vinyl content: 70% by mass, weight average molecular weight: 4500)

[0545] • Softener 8: Dercolyte L120 (polypropylene resin, softening point: 120°C) manufactured by DRT Corporation

[0546] • Silane coupling agent 1: Si266 manufactured by Evonik Degussa

[0547] • Silane coupling agent 2: Si69 manufactured by Evonik Degussa

[0548] • Silane coupling agent 3: Si363 manufactured by Evonik Degussa

[0549] • Anti-aging agent: NOCRAC 6C manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0550] • Stearic acid: Beads Stearic Acid "Tsubaki" manufactured by Nippon Oil Co., Ltd.

[0551] • Zinc oxide: Zinc Oxide III manufactured by Hakusui Tech Co., Ltd.

[0552] • Wax: Ozoace 0355 manufactured by Nippon Seiwa Co., Ltd.

[0553] • Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.

[0554] • Vulcanization accelerator 1: NOCCELER CZ manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0555] • Vulcanization accelerator 2: NOCCELER D manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0556] (Evaluation of mixing methods and the moldability of rubber compositions)

[0557] The above materials are mixed by the following method to obtain a rubber composition for crosslinking.

[0558] The rubber compositions of each example and comparative example were prepared according to the proportions recorded in Tables 3 to 5.

[0559] Using a closed mixing mill (0.3L capacity) equipped with a temperature control device as the first stage of mixing, the rubber components, silica, carbon black, silane coupling agent, softener, zinc white and stearic acid are mixed under the conditions of 65% filling rate and rotor speed of 30-50 rpm.

[0560] At this point, the temperature of the closed mixer is controlled, and each rubber composition (mixture) is obtained at a discharge temperature of 155-160°C.

[0561] Next, as the second stage of mixing, the obtained mixture is cooled to room temperature, an anti-aging agent is added, and mixing is performed again to improve the dispersion of silica. In this case, the discharge temperature of the mixture is also adjusted to 155-160°C by controlling the temperature of the mixer.

[0562] After cooling, as the third stage of mixing, sulfur and vulcanization accelerators 1 and 2 are added and mixed in an open mill set at 70°C. After mixing, the moldability of the rubber composition is evaluated based on the surface roughness of the crosslinking rubber composition sheets discharged from the open mill.

[0563] The mixture was then molded and vulcanized at 160°C using a pressure vulcanizing machine. The vulcanized rubber composition was then evaluated.

[0564] The vulcanization time was set as the T90 (minutes) of each sample determined by the method described later, plus 5 minutes.

[0565] Specifically, the evaluation was conducted using the following methods. The evaluation results are shown in Tables 3 to 5.

[0566] <Evaluation 1: Vulcanization rate of the rubber composition>

[0567] For the evaluation of the vulcanization rate of the rubber composition, the vulcanization time T90 (minutes) was determined according to ISO 6502 using the MDR3000 manufactured by Montec.

[0568] In Tables 3 to 5, the T90 of the reference example is set to 100 and quantified, and evaluated according to the following indicators.

[0569] 〇: The vulcanization rate index of the rubber composition is 95 or higher.

[0570] △: The vulcanization rate index of the rubber composition is above 80 and less than 95.

[0571] ×: The vulcanization rate index of the rubber composition is less than 80.

[0572] <Evaluation 2: Fuel-saving performance of the rubber composition>

[0573] Viscoelastic parameters were determined using a viscoelastic testing machine, ARES, manufactured by Rheometric Scientific, in torsional vibration mode. The tanδ value measured at 50°C, 10 Hz, and 3% strain was used as an indicator of fuel-saving performance. The fuel-saving speed of the reference example was set to 100, and the evaluation was conducted according to the following indicators.

[0574] ◎: The fuel-saving performance index of sulfides is above 110.

[0575] ○: The fuel-saving performance index of sulfides is above 105 and less than 110.

[0576] △: The fuel-saving performance index of sulfides is above 95 and less than 105.

[0577] ×: The fuel-saving performance index of sulfides is less than 95.

[0578] <Evaluation 3: Tensile Strength>

[0579] The tensile strength was determined according to the tensile test method of JIS K6251.

[0580] In Tables 3 to 5, the tensile strength values ​​of the reference examples are set to 100, and the following indicators are used for evaluation.

[0581] ◎: The tensile strength index of the sulfide is 110 or higher.

[0582] ○: The tensile strength index of the sulfide is 105 or higher and less than 110.

[0583] △: The tensile strength index of the sulfide is 95 or higher and less than 105.

[0584] ×: The tensile strength index of the sulfide is less than 95.

[0585] <Evaluation 4: Tear Strength>

[0586] Tear strength was determined using a trouser-shaped test piece according to Test Method A of JIS K6252.

[0587] In Tables 3 to 5, the tensile strength values ​​of the reference examples are set to 100, and the following indicators are used for evaluation.

[0588] ◎: The tear strength index of sulfides is 110 or higher.

[0589] ○: The tear strength index of sulfide is 105 or higher and less than 110.

[0590] △: The tear strength index of sulfide is 95 or higher and less than 105.

[0591] ×: The tear strength index of sulfides is less than 95.

[0592]

[0593]

[0594]

[0595] As shown in Tables 3 to 5, compared with Comparative Examples 9 to 16, there were no × in the evaluation results of Examples 13 to 36, confirming that the balance of vulcanization speed, fuel-saving performance, tensile strength and tear strength was excellent.

[0596] This application is based on Japanese Patent Application No. 2021-011623, filed with the Japan Patent Office on January 28, 2021, the contents of which are incorporated herein by reference.

[0597] Industrial applicability

[0598] The rubber-like polymer of the present invention has industrial applicability in the fields of tire treads, automotive interior and exterior materials, shock-absorbing rubber, belts, footwear, foams, and various industrial products.

Claims

1. A rubber-like polymer, wherein, The sum of the content C1 of the structure represented by equation (1) and the content C2 of the structure represented by equation (2) is 40 mol% or more and 60 mol% or less. The content of C3 in the structure represented by the following formula (3) is more than 15 mol% and less than 50 mol%. The content of C4 in the structure represented by the following formula (4) is more than 5 mol% and less than 25 mol%. The content of aromatic vinyl monomer units S is between 4 mol% and 15 mol%. The weight-average molecular weight, as determined by gel permeation chromatography (GPC), is over 300,000. The ratio of weight-average molecular weight Mw to Mooney viscosity ML measured at 100°C, Mw / (ML×10000), is between 0.68 and 0.

85. The modification rate, determined by column adsorption GPC, is above 60% by mass. This modification rate refers to the rate of modification using nitrogen-containing functional groups. [Chemistry 1] 。 2. The rubber-like polymer as claimed in claim 1, wherein, The nitrogen content is between 10 ppm and 80 ppm.

3. The rubber-like polymer as described in claim 2, wherein, The nitrogen content is between 35 ppm and 80 ppm.

4. The rubber-like polymer as described in claim 1 or 2, wherein, The silicon content is between 50 ppm and 200 ppm.

5. The rubber-like polymer as described in claim 1 or 2, wherein, The weight-average molecular weight, determined by gel permeation chromatography (GPC), is between 300,000 and 700,000.

6. The rubber-like polymer of claim 4, wherein, The silicon content is between 80 ppm and 200 ppm.

7. The rubber-like polymer as claimed in claim 1 or 2, wherein, The ratio of weight-average molecular weight Mw to Mooney viscosity ML measured at 100°C, Mw / (ML×10000), is 0.73 or higher and 0.84 or lower.

8. The rubber-like polymer as claimed in claim 1 or 2, wherein, The hydrogenation rate of the structural units derived from conjugated diene compounds is below 90%.

9. The rubber-like polymer of claim 8, wherein, The hydrogenation rate of the structural units derived from conjugated diene compounds is above 50% and below 85%.

10. A method for manufacturing a rubber-like polymer, wherein the method for manufacturing the rubber-like polymer according to any one of claims 1 to 9, wherein, This method has the following steps: The conjugated diene compound was copolymerized with an aromatic vinyl compound, and the resulting copolymer was hydrogenated to a hydrogenation rate of less than 90%.

11. The method for manufacturing the rubbery polymer as described in claim 10, wherein, The hydrogenation process is carried out in a manner with a hydrogenation rate of 50% to 85%.

12. The method for manufacturing the rubbery polymer as described in claim 10 or 11, wherein, The copolymerization process involves a modification step using a modifier.

13. The method for manufacturing the rubbery polymer as described in claim 12, wherein, The modifier has both nitrogen atoms and silicon atoms.

14. A rubber composition comprising: 100 parts by weight of a rubber component comprising the rubber-like polymer according to any one of claims 1 to 9; and Crosslinking agent of 0.1 to 20 parts by weight.

15. A rubber composition comprising: 100 parts by weight of a rubber component comprising the rubber-like polymer according to any one of claims 1 to 9; and Silane coupling agents, ranging from 0.1 parts by weight to 30 parts by weight.

16. A rubber composition comprising: 100 parts by weight of a rubber component comprising the rubber-like polymer according to any one of claims 1 to 9; and A plasticizer consisting of 1 to 60 parts by weight.

17. A rubber composition comprising: 100 parts by weight of a rubber component comprising the rubber-like polymer according to any one of claims 1 to 9; and 30 to 100 parts by weight of silicon dioxide.

18. A rubber composition comprising: 100 parts by weight of a rubber component comprising the rubber-like polymer according to any one of claims 1 to 9; and Carbon black of 1 part by weight to 100 parts by weight.

19. A tire tread comprising the rubber composition according to any one of claims 14 to 18.

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