Rubber composition and vulcanized rubber composition

Abstract

A rubber composition comprising, for every 100 parts by mass of a rubber component containing at least one type of conjugated diene polymer, 10 parts by mass or more and 150 parts by mass or less of carbon black, wherein the content of a silica-based inorganic filler is 0% by mass or more and 30% by mass or less relative to the total amount of filler, wherein 10% or more by mass of the rubber component is a modified conjugated diene polymer, and wherein the modified conjugated diene polymer is (1) The main chain has a branched structure, and the main chain has a branched structure, and (2) The main chain branching structure comprises a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and a structure derived from an aromatic vinyl monomer, and (3) At least one terminal, the molecule has at least one carbonyl group and at least one substituted amino group, and (4) The Mooney viscosity measured at 100°C is 30 to 120, and (5) The branching degree (Bn) by the GPC-light scattering method with a viscosity detector is 1.1 or higher and less than 4.0, and (6) The chromatographic shape measured by gel permeation chromatography (GPC) is unimodal, and the molecular weight distribution is 1.60 to 3.00, and (7) A rubber composition having a hydrogenation rate of less than 10 mol%.

Description

Technology Field

[0001] The present invention relates to a composition of a modified conjugated diene polymer, and specifically to a rubber composition and a vulcanized rubber composition comprising a modified conjugated diene polymer. Background Technology

[0002] Since the demand for lower fuel consumption in automobiles has been increasing, there is a need for improvements in the rubber materials used in automobile tires, particularly in the tire treads that come into contact with the road surface.

[0003] In particular, as a performance requirement for heavy-duty tires used in large vehicles such as trucks or buses, there is a demand for tires that improve fuel efficiency with low energy loss, in addition to conventional characteristics such as high strength and wear resistance to support heavy loads. Specifically, for the rubber material used in the tread of heavy-duty tires, a rubber composition with high tensile strength and excellent fuel efficiency is required.

[0004] As a rubber material in accordance with the requirements described above, for example, a modified conjugated diene polymer having hydroxyl groups at the ends of the polymer chains and a composition thereof, or a method and composition for manufacturing a conjugated diene polymer in which a specific compound such as a hydrocarbyloxysilane compound is reacted at the ends of the polymer chains and then further reacted (see, for example, Patent Documents 1 and 2).

[0005] However, for heavy-duty tires, rubber compositions incorporating carbon black are still suitable for use in terms of durability and wear resistance. Although there is a demand for rubber compositions that improve fuel efficiency, wear resistance, and tensile strength in compositions incorporating carbon black as a filler, there is a problem in that fuel efficiency, wear resistance, and tensile strength are not sufficiently exhibited if the dispersion state of the filler within the rubber composition is insufficient.

[0006] Meanwhile, rubber products used as industrial goods also have rubber compositions incorporating carbon black suitable for use in terms of durability and processability, and, for example, as anti-vibration rubber for automobiles or tanks, rubber materials containing natural rubber with excellent anti-vibration properties such as compression permanent deformation and dynamic magnification have been proposed (see, for example, Patent Document 3). Prior art literature

[0007] Japanese Patent Publication No. 2017-171806, International Publication No. 03 / 046020, Pamphlet, Japanese Patent Publication No. 2004-292679 The problem to be solved

[0008] However, in recent rubber materials, there are cases where the anti-vibration properties are insufficient, and in particular, in rubber compositions containing carbon black, if the dispersibility of the filler is insufficient, there is a problem in that the anti-vibration properties are not sufficiently expressed.

[0009] In addition, modified conjugated diene polymers suitable for use in heavy-duty tire treads and industrial products have a problem in that the bales in the form of products tend to flow easily (hereinafter referred to as "cold flow"), making it difficult to handle the bales after storage.

[0010] Against this background, regarding a rubber composition incorporating carbon black, it is desired to provide a rubber composition with excellent processability when the rubber composition is incorporating carbon black, and excellent fuel efficiency, tensile strength, wear resistance, and anti-vibration properties when the rubber composition is vulcanized. However, there is a problem in that the processability of the rubber composition and the tensile strength and wear resistance when vulcanized are inversely related to each other, making it difficult to achieve compatibility.

[0011] Accordingly, in order to solve the aforementioned problem, the present invention aims to provide a rubber composition and a vulcanized rubber composition comprising carbon black and a modified conjugated diene polymer with suppressed cold flow properties, which have excellent processability and highly compatible fuel efficiency, tensile strength, wear resistance, and anti-vibration properties when the composition is vulcanized. means of solving the problem

[0012] As a result of diligent research and review to solve the problems of the prior art described above, the inventors have provided a rubber composition comprising, for every 100 parts by mass of a rubber component containing at least one conjugated diene polymer, 10 parts by mass or more and 150 parts by mass or less of carbon black, and a silica-based inorganic filler content of 0% by mass or more and 30% by mass or less relative to the total amount of filler.

[0013] By using a specific or modified conjugated diene polymer in an amount of 10 mass% or more of the rubber component, it was discovered that the rubber composition has excellent processability and, when vulcanized, has excellent fuel efficiency, tensile strength, wear resistance, and anti-vibration properties, leading to the completion of the present invention.

[0014] That is, the present invention is as follows.

[0015] <1>

[0016] A rubber composition comprising 10 to 150 parts by mass of carbon black per 100 parts by mass of a rubber component comprising at least one conjugated diene polymer, wherein the content of a silica-based inorganic filler is 0 to 30 parts by mass relative to the total amount of filler.

[0017] The rubber composition is one in which 10 mass% or more of the above rubber component is a modified conjugated diene polymer, and

[0018] The above modified conjugated diene-based polymer is,

[0019] (1) The main chain has a branched structure, and the main chain has a branched structure, and

[0020] (2) The main chain branching structure comprises a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and a structure derived from an aromatic vinyl monomer, and

[0021] (3) At least one terminal, the molecule has at least one carbonyl group and at least one substituted amino group, and

[0022] (4) The Mooney viscosity measured at 100°C is 30 to 120, and

[0023] (5) The branching degree (Bn) by the GPC-light scattering method with a viscosity detector is 1.1 or higher and less than 4.0, and

[0024] (6) The chromatographic shape measured by gel permeation chromatography (GPC) is unimodal, and the molecular weight distribution is 1.60 to 3.00, and

[0025] (7) Hydrogen addition rate of less than 10 mol%,

[0026] Rubber composition.

[0027] <2>

[0028] The above modified conjugated diene polymer, wherein the 1,2-vinyl bond content in the conjugated diene unit is 10 mol% or more and 25 mol% or less, <1> Rubber composition described in

[0029] <3>

[0030] The above modified conjugated diene-based polymer having an aromatic vinyl bond content of 0 mass% or more and 10 mass% or less, the above <1> or <2> Rubber composition described in

[0031] <4>

[0032] The glass transition temperature (Tg) of the above modified conjugated diene polymer is -110℃ to -80℃, the above <1> inside <3> A rubber composition described in any of the

[0033] <5>

[0034] The modification rate of the above-mentioned modified conjugated diene polymer, measured by column adsorption GPC, is 40 mass% or more, the above <1> inside <4> A rubber composition described in any of the

[0035] <6>

[0036] The hydrogenation rate of the above modified conjugated diene polymer is less than 5 mol%, the above <1> inside <5> A rubber composition described in any of the

[0037] <7>

[0038] The above modified conjugated diene polymer has a structure represented by the following formula (1) and / or the following formula (2), the above <1> inside <6> A rubber composition described in any of the

[0039]

[0040] (In Formula (1), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and Ra and Rb each independently represent a hydrocarbon group having 1 to 20 carbon atoms.)

[0041]

[0042] (In Formula (2), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and Ra and Rb each independently represent a hydrocarbon group having 1 to 20 carbon atoms.)

[0043] <8>

[0044] The main chain branching structure of the above-mentioned modified conjugated diene polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and in the portion derived from the vinyl monomer containing the alkoxysilyl group or a halosyl group, the portion having the branching structure <1> inside <7> A rubber composition described in any of the

[0045] <9>

[0046] The portion derived from the vinyl monomer containing the alkoxysilyl group or halosyl group is a monomer unit derived from a compound represented by the following formula (3) or the following formula (4), and

[0047] The branch structure among the main chain branch structures of the above-mentioned modified conjugated diene polymer has a branch point of the polymer chain formed by a monomer unit derived from a compound represented by the following formula (3) or the following formula (4). <8> Rubber composition described in

[0048]

[0049] (during food, R 1 It represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure on silver, hydrogen atoms, or a part thereof, and

[0050] R 2 to R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a part thereof, and

[0051] R in the case where multiple exist 1 to R 3 Each is independent.

[0052] X 1 Silver represents an independent halogen atom,

[0053] m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, and (m+n+l) is 3.

[0054]

[0055] (during food, R 2 to R 5 Each represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a part thereof, and R in the case where multiple groups exist. 2to R 5 are, each independent, and

[0056] X 2 To X 3 Each represents an independent halogen atom, and

[0057] m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, (m+n+l) is 3, and

[0058] a represents an integer from 0 to 2, b represents an integer from 0 to 3, c represents an integer from 0 to 3, and (a+b+c) is 3.

[0059] <10>

[0060] The main chain branching structure of the above modified conjugated diene polymer has monomer units derived from the compound represented by the above formula (3), and among the above formula (3), R 1 Representing this hydrogen atom, and m representing 0, the above <9> Rubber composition described in

[0061] <11>

[0062] The main chain branching structure of the above modified conjugated diene polymer has monomer units derived from the compound represented by the above formula (4), wherein in the above formula (4), m represents 0 and b represents 0, the <8> or <10> Rubber composition described in

[0063] <12>

[0064] The main chain branching structure of the above modified conjugated diene polymer has monomer units derived from the compound represented by the above formula (3), and among the above formula (3), R 1 Representing this hydrogen atom, where m represents 0, n represents 3, and l represents 0, the above <9> inside <11> A rubber composition described in any of the

[0065] <13>

[0066] The main chain branching structure of the above modified conjugated diene polymer has monomer units derived from the compound represented by the above formula (4), wherein in the above formula (4), m represents 0, n represents 3, l represents 0, a represents 0, b represents 0, and c represents 3, the above <9> Rubber composition described in

[0067] <14>

[0068] The above <1> inside <13> A vulcanized rubber composition obtained by vulcanizing the rubber composition described in any of the above. Effects of the invention

[0069] According to the present invention, by using carbon black and a modified conjugated diene polymer that suppresses cold flow, it is possible to provide a rubber composition and a vulcanized rubber composition that have excellent processability and also highly compatible fuel efficiency, tensile strength, wear resistance, and anti-vibration properties when the composition is vulcanized. Specific details for implementing the invention

[0070] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as “the present embodiments”), but the present invention is not limited thereto and various modifications are possible within the scope of not departing from the gist thereof. In addition, expressions in the specification in which numerical values ​​are connected by “to,” for example, x to y (where x and y are each numerical values), refer to a numerical range including x and y as an upper or lower limit.

[0071] Rubber composition

[0072] The rubber composition of the present embodiment comprises, for every 100 parts by mass of a rubber component comprising at least one conjugated diene polymer, 10 parts by mass or more and 150 parts by mass of carbon black, and the content of a silica-based inorganic filler is 0% by mass or more and 30% by mass or less relative to the total amount of filler, wherein 10% or more by mass of the rubber component is a modified conjugated diene polymer.

[0073] (1) The main chain has a branched structure, and the main chain has a branched structure, and

[0074] (2) The main chain branching structure comprises a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and a structure derived from an aromatic vinyl monomer, and

[0075] (3) At least one terminal, the molecule has at least one carbonyl group and at least one substituted amino group, and

[0076] (4) The Mooney viscosity measured at 100°C is 30 to 120, and

[0077] (5) The branching degree (Bn) by the GPC-light scattering method with a viscosity detector is 1.1 or higher and less than 4.0, and

[0078] (6) The chromatographic shape measured by gel permeation chromatography (GPC) is unimodal, and the molecular weight distribution is 1.60 to 3.00, and

[0079] (7) The hydrogen addition rate is less than 10 mol%.

[0080] Modified conjugated diene polymers will be described later.

[0081] [Rubber polymer other than the modified conjugated diene polymer in the present embodiment]

[0082] As described above, the rubber composition of the present embodiment comprises a rubber component comprising at least one conjugated diene polymer and carbon black. In addition to the modified conjugated diene polymer described below, the rubber composition of the present embodiment may additionally use a rubbery polymer other than said modified conjugated diene polymer (hereinafter simply referred to as "rubbery polymer") as a rubber component.

[0083] Examples of such rubbery polymers include, but are not particularly limited, conjugated diene polymers or their hydrogenated derivatives, random copolymers of conjugated diene compounds and vinyl aromatic compounds or their hydrogenated derivatives, block copolymers of conjugated diene compounds and vinyl aromatic compounds or their hydrogenated derivatives, non-diene polymers, and natural rubber.

[0084] Specific conjugated diene polymers are not particularly limited, but examples include butadiene rubber or its hydrogenated derivative, isoprene rubber or its hydrogenated derivative, styrene-butadiene rubber or its hydrogenated derivative, styrene-butadiene block copolymer or its hydrogenated derivative, styrene-isoprene block copolymer or its hydrogenated derivative, styrene-based elastomers, acrylonitrile-butadiene rubber or its hydrogenated derivative.

[0085] Examples of non-diene polymers include, but are not particularly limited, olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, ethylene-octene rubber, butyl rubber, butyl bromide rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0086] Natural rubber is not particularly limited, but examples include smoked sheets RSS3 to 5, SMR, and epoxidized natural rubber.

[0087] The various rubbery polymers described above may be modified rubbers imparted with polar functional groups such as hydroxyl groups and amino groups. When used for tires, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber are preferably used.

[0088] The weight-average molecular weight of the rubbery polymer is preferably 2,000 or more and 2,000,000 or less, and more preferably 5,000 or more and 1,500,000 or less, from the perspective of the balance of performance and processing characteristics. In addition, as the rubbery polymer, a low molecular weight rubbery polymer, so-called liquid rubber, may be used. These rubbery polymers may be used as a single type or two or more types may be used in combination.

[0089] In the present embodiment, when the rubber composition comprises the modified conjugated diene polymer and the rubbery polymer described below, the content ratio (mass ratio) of the modified conjugated diene polymer to the rubbery polymer is preferably 10 / 90 or more and 100 / 0 or less as (modified conjugated diene polymer / rubbery polymer), more preferably 20 / 80 or more and 90 / 10 or less, and even more preferably 40 / 60 or more and 80 / 20 or less.

[0090] Accordingly, the rubber component comprises, with respect to the total amount (100 parts by mass) of the rubber component, the modified conjugated diene polymer described below, preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 90 parts by mass or less, and even more preferably 40 parts by mass or more and 80 parts by mass or less.

[0091] If the content ratio of (modified conjugated diene polymer / rubber-like polymer) is within the range described above, the wear resistance and tensile strength are excellent when made into a vulcanized rubber composition, and the balance of fuel efficiency and wet skid resistance and dustproof performance are excellent.

[0092] 〔filling〕

[0093] (Carbon Black)

[0094] The carbon black included in the rubber composition of the present embodiment is not particularly limited, but examples include carbon black of each class such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area of ​​50 m² / g or more and a dibutyl phthalate (DBP) oil absorption amount of 80 mL / 100 g or less is preferred.

[0095] In the rubber composition of the present embodiment, the carbon black content is preferably 10 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the rubber component, more preferably 25 parts by mass or more and 125 parts by mass or less, and even more preferably 30 parts by mass or more and 100 parts by mass or less.

[0096] In the cross-linked rubber composition of the present embodiment, the carbon black content is preferably 10 parts by mass or more per 100 parts by mass of the rubber component from the perspective of exhibiting performance required for industrial use, such as hardness or dustproof properties, and is preferably 150 parts by mass or less per 100 parts by mass of the rubber component from the perspective of dispersibility.

[0097] (Fillings other than carbon black)

[0098] The rubber composition of the present embodiment may include fillers other than carbon black.

[0099] As fillers other than carbon black, examples include silica-based inorganic fillers, metal oxides, and metal hydroxides, although they are not particularly limited. Among these, silica is preferred.

[0100] The filler may be used as a single type or in combination with two or more types.

[0101] As for the silica-based inorganic filler, there are no particular limitations and known ones may be used, but solid particles containing SiO2 or Si3Al as constituent units are preferred, and solid particles containing SiO2 or Si3Al as the main component of the constituent units are more preferred. Here, the main component refers to a component contained in the silica-based inorganic filler in an amount of 50 mass% or more, preferably 70 mass% or more, and more preferably 80 mass% or more.

[0102] Specific silica-based inorganic fillers are not particularly limited, but examples include inorganic fibrous materials such as silica, clay, talc, mica, diatomite, wollastonite, montmorillonite, zeolite, and glass fiber. Additionally, silica-based inorganic fillers with hydrophobic surfaces and mixtures of silica-based inorganic fillers and non-silica-based inorganic fillers may be used. Among these, silica and glass fiber are preferred from the perspective of strength and wear resistance, and silica is more preferred. Examples of silica include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred.

[0103] In order to obtain practically good wear resistance and fracture strength of the vulcanized rubber composition, the nitrogen adsorption specific surface area obtained by the BET adsorption method of the silica-based inorganic filler is preferably 100 m² / g or more and 300 m² / g or less, and more preferably 170 m² / g or more and 250 m² / g or less. In addition, if necessary, a silica-based inorganic filler with a relatively small specific surface area (e.g., a specific surface area of ​​200 m² / g or less) and a silica-based inorganic filler with a relatively large specific surface area (e.g., 200 m² / g or more) may be used in combination.

[0104] The content of silica-based inorganic filler in the rubber composition is 30 mass% or less with respect to the total amount of filler, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0105] When a rubber composition includes a silica-based inorganic filler, the lower limit content thereof can be 15 mass% or more, 10 mass% or more, or 5 mass% or more with respect to the total amount of filler.

[0106] In the rubber composition of the present embodiment, the term "metal oxide" refers to a solid particle having the chemical formula MxOy (where M represents a metal atom, and x and y each independently represent integers from 1 to 6) as the main component of the constituent unit.

[0107] Examples of metal oxides include, but are not particularly limited, alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0108] Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide, although they are not particularly limited.

[0109] [Modified Conjugated Diene Polymer]

[0110] The rubber composition of the present embodiment comprises a modified conjugated diene polymer that satisfies (1) to (7) below.

[0111] (1) The main chain has a branched structure, and the main chain has a branched structure, and

[0112] (2) The main chain branching structure comprises a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and a structure derived from an aromatic vinyl monomer, and

[0113] (3) At least one terminal, the molecule has at least one carbonyl group and at least one substituted amino group, and

[0114] (4) The Mooney viscosity measured at 100°C is 30 to 120, and

[0115] (5) The branching degree (Bn) by the GPC-light scattering method with a viscosity detector is 1.1 or higher and less than 4.0, and

[0116] (6) The chromatographic shape measured by gel permeation chromatography (GPC) is unimodal, and the molecular weight distribution is 1.60 to 3.00, and

[0117] (7) The hydrogen addition rate is less than 10 mol%.

[0118] Although not specifically limited, the modified conjugated diene polymer in the present embodiment can be synthesized by polymerizing at least one modified conjugated diene monomer or copolymerizing a conjugated diene monomer and an aromatic vinyl monomer, and adding a branching agent to synthesize a conjugated diene polymer having a main chain branched structure.

[0119] (Method for preparing modified conjugated diene polymers)

[0120] The method for manufacturing a modified conjugated diene polymer in the present embodiment may include a polymerization and branching process in which a conjugated diene monomer is polymerized using an organic lithium compound as a polymerization initiator, and a branching agent described below is added to obtain a conjugated diene polymer having a main chain branched structure, and a modification process in which the conjugated diene polymer is modified by a modifying agent.

[0121] (Polymerization and Branching Process)

[0122] The polymerization and branching process (hereinafter also simply referred to as the “polymerization and branching process”) in the method for manufacturing a modified conjugated diene polymer is a process of obtaining a conjugated diene polymer having a branched structure in the main chain by, for example, using an organic monolithium compound as a polymerization initiator, polymerizing at least one conjugated diene compound, and adding a branching agent. Hereinafter, when describing the polymerization reaction in the polymerization and branching process, it will be referred to as the “polymerization process,” and when describing the reaction with the branching agent, it will be referred to as the “branching process.”

[0123] In the polymerization process, it is preferable to perform polymerization by a growth reaction using a living anionic polymerization reaction, thereby obtaining a conjugated diene polymer having active ends. Subsequently, in a branching process using a branching agent, main chain branching can be appropriately controlled, and there is a tendency to obtain a conjugated diene polymer with a high modification rate.

[0124] Conjugated diene polymers may be homopolymers obtained using a single conjugated diene compound as a monomer, or polymers obtained using different types of conjugated diene compounds as monomers, i.e., copolymers.

[0125] (Conjugated diene monomer)

[0126] Specific examples of conjugated diene monomers in the present embodiment are not particularly limited, but examples include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the perspective of ease of industrial availability. These may be used individually or in combination of two or more types.

[0127] (Aromatic vinyl monomer)

[0128] The aromatic vinyl monomers in this embodiment are not limited to the following, but examples include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the perspective of ease of industrial availability. These may be used as a single type or two or more types may be used in combination.

[0129] (Polymer initiator)

[0130] As a polymerization initiator in this embodiment, at least an organic monolithium compound may be used.

[0131] Organic monolithium compounds are not particularly limited, but examples include low-molecular-weight compounds and organic monolithium compounds of solubilized oligomers.

[0132] In addition, organic monolithium compounds include, for example, compounds having carbon-lithium bonds, compounds having nitrogen-lithium bonds, and compounds having tin-lithium bonds, in terms of the bonding mode between the organic group and the lithium.

[0133] It is preferable to determine the amount of organic monolithium compound used as a polymerization initiator according to the molecular weight of the target conjugated diene polymer.

[0134] The amount of monomers, such as conjugated diene compounds, used relative to the amount of polymerization initiator is related to the degree of polymerization. That is, it tends to be related to the number-average molecular weight and / or weight-average molecular weight.

[0135] Therefore, to increase the molecular weight, the amount of polymerization initiator used should be reduced, and to decrease the molecular weight, the amount of polymerization initiator used should be increased.

[0136] In the sense that the organic monolithium compound is used as a method to introduce nitrogen atoms into conjugated diene polymers, it is preferably an alkyllithium compound having a substituted amino group or a dialkylaminolithium.

[0137] In this case, a conjugated diene polymer having a nitrogen atom containing an amino group at the polymerization initiation end is obtained.

[0138] A substituted amino group is an amino group that does not have an active hydrogen or has a structure in which the active hydrogen is protected.

[0139] Examples of alkyl lithium compounds having an amino group that does not have an active hydrogen include, but are not particularly limited, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0140] Alkylithium compounds having an amino group in a structure that protects active hydrogen are not particularly limited, but examples include 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0141] Examples of dialkylaminolithium include, but are not particularly limited, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium-di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithioazcyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane and 1-lithio-1,2,3,6-tetrahydropyridine.

[0142] These organic monolithium compounds having substituted amino groups can also be used as organic monolithium compounds of solubilized oligomers by reacting a small amount of polymerizable monomers, such as 1,3-butadiene, isoprene, and styrene.

[0143] As for the organic monolithium compound, it is preferably an alkyllithium compound in terms of ease of industrial availability and ease of controlling the polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation end is obtained.

[0144] Examples of alkyl lithium compounds include, but are not particularly limited, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenium.

[0145] As for alkyl lithium compounds, n-butyllithium and sec-butyllithium are preferred from the perspective of ease of industrial availability and ease of controlling the polymerization reaction.

[0146] These organo-monolithium compounds may be used alone or in combination of two or more. In addition, they may be used in combination with other organometallic compounds.

[0147] Other organometallic compounds include, for example, alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0148] Alkaline earth metal compounds are not particularly limited, but examples include organic magnesium compounds, organic calcium compounds, and organic strontium compounds. In addition, compounds of alkaline earth metal alkoxides, sulfonates, carbonates, and amides may also be examples.

[0149] Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0150] (Polymerization method)

[0151] In the polymerization process of the present embodiment, the polymerization reaction mode is not particularly limited, but examples include batch (also called "batch type") and continuous polymerization reaction modes.

[0152] In the continuous type, one or more connected reactors may be used. For example, a tubular reactor equipped with a stirrer is used. In the continuous type, preferably, a monomer, an inert solvent, and a polymerization initiator are continuously supplied to the reactor, a polymer solution containing the polymer is obtained within the reactor, and the polymer solution is continuously discharged.

[0153] For batch reactors, for example, a molded reactor equipped with a stirrer is used. In the batch type, preferably, a monomer, an inert solvent, and a polymerization initiator are supplied, and if necessary, the monomer is added continuously or intermittently during polymerization, and a polymer solution containing the polymer is obtained within the reactor, and the polymer solution is discharged after the polymerization is completed.

[0154] (Polymerization solvent)

[0155] In the present embodiment, the polymerization process of the conjugated diene polymer is preferably carried out in an inert solvent. The solvent is not particularly limited, but examples include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not particularly limited, but examples include 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 including mixtures thereof.

[0156] It is desirable to treat impurities such as allenes and acetylenes with organometallic compounds before providing them to the polymerization reaction, as this tends to yield conjugated diene polymers with a high concentration of active ends and modified conjugated diene polymers with a high modification rate.

[0157] (Polar compounds)

[0158] In the polymerization process, polar compounds may be added. They tend to be used as vinylizing agents to control the amount of 1,2-vinyl bonds in conjugated diene polymers. In addition, they tend to be effective in promoting polymerization reactions.

[0159] As polar compounds, although not particularly limited, examples include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis(2-oxoranyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclideine; alkali metal alkoxide compounds such as potassium-tert-amylate, potassium-tert-butylate, sodium-tert-butylate, sodium amylate; and phosphine compounds such as triphenylphosphine.

[0160] These polar compounds may be used alone or in combination of two or more.

[0161] The amount of polar compound used is not particularly limited and can be selected according to the purpose, but it is preferable that it be 0.01 mole or more and 100 mole or less per 1 mole of polymerization initiator.

[0162] These polar compounds (vinylating agents) can be used as regulators of the microstructure of conjugated diene polymers in appropriate amounts depending on the desired 1,2 vinyl bond amount.

[0163] (Polymerization temperature)

[0164] In the polymerization process, the polymerization temperature is preferably a temperature at which living anionic polymerization proceeds, and from the perspective of productivity, it is more preferable to be 0°C or higher, and even more preferable to be 120°C or lower. By being within this range, it tends to be possible to sufficiently secure the reaction amount of the modifying agent on the active end after the polymerization is completed. More preferably, it is 50°C or higher and 100°C or lower.

[0165] (Branching process)

[0166] The rubber composition of the present embodiment comprises a modified conjugated diene polymer having (1) a main chain branched structure having a branched structure in the main chain, and (2) the main chain branched structure is a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and an aromatic vinyl monomer. The modified conjugated diene polymer can be obtained as a conjugated diene polymer having a main chain branched structure by adding a branching agent while polymerizing at least one conjugated diene monomer, or copolymerizing a conjugated diene monomer and an aromatic vinyl monomer.

[0167] The amount of branching agent added to the branching process for forming a branched structure is not particularly limited and can be selected according to the purpose, etc., but it is preferable that the amount is 0.02 moles or more and 0.5 moles or less per 1 mole of polymerization initiator, more preferable that the amount is 0.03 moles or more and 0.4 moles or less, and even more preferable that the amount is 0.03 moles or more and 0.3 moles or less.

[0168] The branching agent can be used as a branching point for the branching structure of the conjugated diene portion of a conjugated diene polymer, and can be used in an appropriate amount according to the desired number of branching points.

[0169] In the branching process, the timing of adding the branching agent is not particularly limited and can be selected according to the purpose, etc. However, from the perspective of improving the absolute molecular weight and modification rate of the conjugated diene polymer, it is preferable to have a timing where the raw material conversion rate after adding the polymerization initiator is 20% or more, more preferable to have 40% or more, even more preferable to have 50% or more, even more preferable to have 65% or more, and even more preferable to have 75% or more.

[0170] In addition, after adding the branching agent, the desired raw material may be added further, and the polymerization process may be continued after branching, or the above-described contents may be repeated.

[0171] The modified conjugated diene polymer in the present embodiment is not particularly limited and may be a polymer of a conjugated diene monomer and a branching agent, or a copolymer of a conjugated diene monomer, a branching agent, and monomers other than these. For example, when the conjugated diene monomer is butadiene or isoprene and is polymerized with a branching agent containing a vinyl aromatic portion (i.e., an aromatic vinyl monomer), the polymer chain is so-called polybutadiene or polyisoprene, and the polymer becomes a polymer containing a structure derived from vinyl aromatics in the branched portion. By having such a structure, the linearity per polymer chain is improved, the crosslinking density after vulcanization is increased, and the wear resistance is improved. Therefore, the conjugated diene polymer of the present embodiment is suitable for applications such as tires, resin modification, interior and exterior parts of automobiles, anti-vibration rubber, and footwear.

[0172] When the rubber composition of the present embodiment is provided for use in the tread of a heavy-duty tire, a copolymer of a conjugated diene monomer and a branching agent is suitable as the modified conjugated diene polymer.

[0173] (Modified conjugated diene polymer)

[0174] The modified conjugated diene polymer in the present embodiment has (3) a terminal group having at least one carbonyl group and at least one substituted amino group in the molecule at at least one end. The modified conjugated diene polymer in the present embodiment is, for example, a modified conjugated diene polymer modified by a modifying agent having at least one carbonyl group (>C=O group) and at least one substituted amino group in the molecule that reacts with the active end of the conjugated diene polymer. That is, the terminal group having at least one carbonyl group and at least one substituted amino group in the molecule, which is the modified conjugated diene polymer in the present embodiment, is a group formed by modifying the active end with the above-described modifying agent and is a group derived from the structure of the modifying agent.

[0175] In the aforementioned modifying agent, the carbonyl group and the substituted amino group may be adjacent or separated. Examples of compounds in which these functional groups are adjacent include amides, imides, ureas, isocyanuric acids, etc., having a "-C(=O)-N<" bond. Among these, cyclic compounds are preferred, N-substituted cyclic amides and N-substituted cyclic ureas are more preferred, and N-substituted cyclic ureas are particularly preferred. Additionally, examples of compounds in which the carbonyl group and the substituted amino group are separated include N-substituted aminoketones and N-substituted aminoaldehydes, but N-substituted aminoketones are preferred.

[0176] In the present embodiment, two or more types of modifying agents may be used, and the method of adding the modifying agents during the modification process may be simultaneous or separate. When two or more types of modifying agents are used, the modified conjugated diene polymer in the present embodiment becomes a conjugated diene polymer in which two or more terminal groups are modified.

[0177] The amount of modifying agent used is not particularly limited and can be selected according to the purpose, etc., but for 1 mole of polymerization initiator, it is preferable to have 0.10 moles or more and 3.00 moles or less, more preferable to have 0.30 moles or more and 2.00 moles or less, and more preferable to have 0.50 moles or more and 1.50 moles or less.

[0178] In the present embodiment, the modifying agent having at least one carbonyl group and at least one substituted amino group together in the molecule is not particularly limited, but examples of N-substituted cyclic amides include N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, N-methyl-2-piperidone, N-phenyl-2-piperidone, N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, etc.

[0179] N-substituted cyclic ureas are not particularly limited, but examples include 1,3-dimethylethylene urea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, etc.

[0180] N-substituted aminoketones are not particularly limited, but examples include 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, etc.

[0181] N-substituted aminoaldehydes are not particularly limited, but examples include 4-N,N-dimethylaminobenzaldehyde.

[0182] [Structure of terminal groups in modified conjugated diene polymers]

[0183] In the modified conjugated diene polymer of the present embodiment, the terminal group having at least one carbonyl group and at least one substituted amino group in the molecule preferably has a structure (amino group or amide group) represented by, for example, Formula (1) and / or Formula (2) below.

[0184]

[0185] (In formula (1), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and R a and R b Each independently represents a hydrocarbon group having 1 to 20 carbon atoms.

[0186]

[0187] (In formula (2), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and R a and R b Each independently represents a hydrocarbon group having 1 to 20 carbon atoms.

[0188] In this embodiment, the modified conjugated diene polymer has terminal groups as described above, so that when used as a filler, particularly in a rubber composition containing carbon black, the terminal groups interact or bond with the functional groups on the surface of the carbon black, and the dispersion of carbon black in the rubber composition tends to be good, and when used as a vulcanized product, the fuel efficiency and kinetics are excellent.

[0189] In this embodiment, the modifying agent for forming the structure represented by formula (1) is not particularly limited, but examples include 1,3-diethyl-2-imidazolinone, 1,3-dimethyl-2-imidazolinone, 1,3-dipropyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 1-methyl-3-propyl-2-imidazolinone, 1-methyl-3-butyl-2-imidazolinone, 1,3-dihydro-1,3-dimethyl-2H-imidazole-2-one, etc.

[0190] In this embodiment, the modifying agent represented by formula (2) is not particularly limited, but examples include 1,3-diethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-propyl-2-imidazolidinone, etc.

[0191] (Degeneration process)

[0192] In the method for manufacturing a modified conjugated diene polymer according to the present embodiment, a modification process (hereinafter also simply referred to as a "modification process") may be performed in which the conjugated diene polymer obtained through the polymerization and branching process described above is modified by the modifying agent described above.

[0193] In the modification process, a conjugated diene polymer is obtained by modifying one end of the active end of the conjugated diene polymer with the modification agent described above.

[0194] The reaction temperature in the modification process is preferably the same temperature as the polymerization temperature of the conjugated diene polymer, more preferably 0°C or higher and 120°C or lower, and more preferably 50°C or higher and 100°C or lower.

[0195] The reaction time in the modification process is preferably 10 seconds or more, more preferably 30 seconds or more.

[0196] Mixing in the modification process may be either mechanical stirring or stirring by a static mixer.

[0197] If the polymerization process is continuous, it is desirable that the modification process is also continuous.

[0198] In the modification process, reactors are used, for example, tubular or molded types equipped with stirrers.

[0199] The modifying agent may be diluted with an inert solvent and continuously supplied to the reactor. In the case of a batch polymerization process, the modifying agent may be introduced directly into the polymerization reactor, or the modification process may be performed by transferring it to a separate reactor.

[0200] The time from the polymerization process to the modification process should be short, preferably within 10 minutes, and more preferably within 5 minutes. In that case, a conjugated diene polymer with high modification efficiency tends to be obtained.

[0201] The time from the polymerization process to the modification process refers to, for example, the time from reaching the peak temperature of polymerization until the addition of the modification agent when the polymerization process is batch, and the time from the addition of the modification agent to the solution containing the conjugated diene polymer exiting the polymerization reactor when the polymerization process is continuous.

[0202] In this embodiment, after the modification process, a condensation reaction process may be additionally performed in the presence of a condensation promoter.

[0203] The conjugated diene polymer of the present embodiment may hydrogenate the conjugated diene portion in the conjugated diene polymer chain.

[0204] The method for hydrogenating the conjugated diene portion of a conjugated diene polymer is not particularly limited, and known methods may be used.

[0205] Suitable hydrogenation methods include hydrogenation by blowing gaseous hydrogen into a polymer solution in the presence of a catalyst. The catalyst is not particularly limited, but examples include heterogeneous catalysts, such as catalysts in which precious metals are supported on porous inorganic materials; homogeneous catalysts, such as catalysts in which salts of nickel, cobalt, etc., are solubilized and reacted with organoaluminum, etc.; and catalysts using metallocenes such as titanocene. Among these, a titanocene catalyst is preferred from the perspective of being able to select mild hydrogenation conditions. Furthermore, hydrogenation of aromatic groups can be performed by using a catalyst supported with a precious metal.

[0206] As hydrogenation catalysts, examples include (1) a supported heterogeneous hydrogenation catalyst in which metals such as Ni, Pt, Pd, Ru are supported on carbon, silica, alumina, diatomaceous earth, etc., (2) a so-called Ziegler-type hydrogenation catalyst using a transition metal salt such as an organic acid salt of Ni, Co, Fe, Cr, etc. or an acetylacetone salt, etc. and a reducing agent such as an organoaluminum, (3) so-called organometallic complexes such as organometallic compounds such as Ti, Ru, Rh, Zr, etc. Additionally, as a hydrogenation catalyst, although not particularly limited, known hydrogenation catalysts described in, for example, Japanese Patent Publication No. Sho 42-8704, Japanese Patent Publication No. Sho 43-6636, Japanese Patent Publication No. Sho 63-4841, Japanese Patent Publication No. Hei 1-37970, Japanese Patent Publication No. Hei 1-53851, Japanese Patent Publication No. Hei 2-9041, and Japanese Patent Publication No. Hei 8-109219 may be cited. As a preferred hydrogenation catalyst, a reaction mixture of a titanocene compound and a reducing organometallic compound may be cited.

[0207] The reaction temperature of the hydrogenation reaction is preferably the same as the polymerization temperature of the conjugated diene polymer, preferably 0°C or higher and 120°C or lower, and more preferably 50°C or higher and 100°C or lower.

[0208] The reaction time for the hydrogenation reaction is preferably 10 seconds or more, more preferably 30 seconds or more.

[0209] The hydrogenation reaction may be carried out by any of the following: mechanical stirring, stirring by a static mixer, etc.

[0210] When the polymerization process is continuous, it is desirable that the hydrogenation reaction is also continuous.

[0211] In hydrogenation reactions, the reactor used is, for example, a tubular type equipped with a stirrer.

[0212] The hydrogenation catalyst may be diluted with an inert solvent and continuously supplied to the reactor. In the case of a batch polymerization process, the hydrogenation catalyst may be introduced directly into the polymerization reactor to blow in hydrogen and carry out the hydrogenation reaction, or the catalyst may be transferred to a separate reactor to carry out the hydrogenation reaction.

[0213] In the method for manufacturing a conjugated diene-based polymer according to the present embodiment, after the modification process, an inactivating agent, a neutralizing agent, etc. may be added to the polymer solution as needed.

[0214] Examples of deactivating agents include, but are not particularly limited, water; alcohols such as methanol, ethanol, and isopropanol.

[0215] Examples of neutralizing agents include, but are not particularly limited, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of highly branched carboxylic acids with 9 to 11 carbon atoms and 10 centrally located); aqueous solutions of inorganic acids and carbon dioxide.

[0216] In the method for manufacturing a modified conjugated diene polymer according to the present embodiment, it is preferable to add a rubber stabilizer from the perspective of preventing gel formation after polymerization and improving stability during processing.

[0217] As a rubber stabilizer, known ones may be used, not limited to the following, but, for example, antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propinate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol are preferred.

[0218] In order to further improve the productivity of the modified conjugated diene polymer in this embodiment and the processability when the composition is formulated with fillers, etc., a rubber softener may be added as needed.

[0219] As rubber softeners, examples include, but are not particularly limited, extension oil, liquid rubber, resin, etc.

[0220] As a method for adding a rubber softener to a conjugated diene polymer, there are no particular limitations, but a method of adding a rubber softener to a conjugated diene polymer solution, mixing to form a polymer solution containing a rubber softener, and then desolvating the resulting solution is preferred.

[0221] Preferred new oils include, for example, aroma oils, naphthenic oils, and paraffin oils. Among these, from the perspective of environmental safety, oil bleed prevention, and wet grip characteristics, an aroma substitute oil having a polycyclic aromatic (PCA) component of 3 mass% or less according to the IP346 method is preferred. As aroma substitute oils, examples include TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) as described in Kautschuk Gummi Kunststoffe 52(12) 799(1999), as well as RAE (Residual Aromatic Extracts).

[0222] Preferred liquid rubbers are not particularly limited, but examples include liquid polybutadiene, liquid styrene-butadiene rubber, etc.

[0223] As an effect of adding liquid rubber, in addition to improving processability when the composition is formulated with conjugated diene polymers and fillers, the glass transition temperature of the composition can be shifted toward the low temperature side, thereby improving wear resistance, low hysteresis loss, and low temperature properties when the composition is vulcanized.

[0224] Preferred resins are not particularly limited, but examples include aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, derivatives of tall oil, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, aromatic hydrocarbon resins, aromatic petroleum resins, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, hydrogenated oil resins, and esters of monofunctional or polyfunctional alcohols. These resins may be used as a single type or in combination of two or more types. When hydrogenating, all unsaturated groups may be hydrogenated, or some may be left intact.

[0225] As an effect of adding resin, in addition to improving processability when using a composition mixed with a conjugated diene polymer and a filler, there is a tendency to improve fracture strength when using a vulcanized material, and also a tendency to improve wet skid resistance by shifting the glass transition temperature of the composition toward a high temperature.

[0226] The amount of extension oil, liquid rubber, or resin added as a rubber softener is not particularly limited, but with respect to 100 parts by mass of the modified conjugated diene polymer in the present embodiment, it is preferably 1 part by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, and even more preferably 10 parts by mass or more and 37.5 parts by mass or less.

[0227] When a rubber softener is added within the above range, the processability of the composition, such as a conjugated diene polymer and a filler, is improved, and the fracture strength and wear resistance of the vulcanized product tend to be improved.

[0228] (Desolvent Process)

[0229] In the method for manufacturing a modified conjugated diene polymer according to the present embodiment, known methods may be used to obtain the obtained modified conjugated diene polymer from a polymer solution. The methods are not particularly limited, but examples include a method of obtaining the polymer by separating the solvent by steam stripping, etc., filtering and fractionating the polymer, and further dehydrating and drying it, a method of concentrating in a flushing tank and further degassing with a vent extruder, etc., or a method of directly degassing with a drum dryer, etc.

[0230] (Moon's viscosity)

[0231] The modified conjugated diene polymer in this embodiment has a Mooney viscosity of 30 to 120 measured at 100°C. Specifically, in terms of the productivity of the conjugated diene polymer, processability when the composition is mixed with fillers, and wear resistance and fracture strength when the composition is vulcanized, the Mooney viscosity of the modified conjugated diene polymer in this embodiment measured at 100°C is 30 or higher and 120 or lower, preferably 35 or higher and 100 or lower, and more preferably 40 or higher and 90 or lower.

[0232] By having a Mooney viscosity of 30 or higher measured at 100°C, the wear resistance and fracture strength are improved when made into a vulcanized material, and by having a Mooney viscosity of 120 or lower measured at 100°C, impediments to the manufacture of conjugated diene polymers are suppressed, and processability is improved when made into a composition containing fillers, etc.

[0233] Mooney viscosity is measured by using a sample of a conjugated diene polymer formed into a plate shape by a pressure press, setting it in a device, preheating the sample at 100°C for 1 minute, rotating the rotor at 2 rpm, measuring the torque after 4 minutes, and defining the measured value as the Mooney viscosity (ML(1+4)). More specifically, it can be measured by the method described in the examples described below. The Mooney viscosity of the conjugated diene polymer can be controlled to the above-described range by controlling conditions such as temperature conditions during the polymerization process, for example, or by adjusting the degree of branching during the branching process.

[0234] (Branch map(Bn))

[0235] The modified conjugated diene polymer in this embodiment has a branching degree (Bn) of 1.1 or higher and less than 4.0 by the GPC-light scattering method with a viscosity detector (5). Specifically, the modified conjugated diene polymer in this embodiment has a branching degree (Bn) of 1.1 or higher and less than 4.0 by the GPC-light scattering method with a viscosity detector, in terms of processability, wear resistance, and fracture strength.

[0236] The fact that the degree of branching (Bn) is less than 4.0 means that the modified conjugated diene polymer in this embodiment has fewer than 4 polymer chains with a branched structure relative to the longest polymer main chain.

[0237] The branching degree (Bn) of a conjugated diene polymer is defined as g' = 6Bn / {(Bn+1)(Bn+2)} using the shrinkage factor (g') measured by the viscometer-attached GPC-light scattering method.

[0238] Generally, branched polymers tend to have smaller molecular sizes compared to straight-chain polymers of the same absolute molecular weight.

[0239] The shrinkage factor (g') is an indicator of the ratio of the size of a molecule to that of a linear polymer having the same absolute molecular weight. In other words, as the degree of branching of the polymer increases, the shrinkage factor (g') tends to decrease.

[0240] In this embodiment, regarding this shrinkage factor, intrinsic viscosity is used as an indicator of molecular size, and for a linear polymer, intrinsic viscosity [η] = 10 -3.883 ×M 0.771 It is assumed to follow the relationship formula. In the formula above, M is the absolute molecular weight.

[0241] However, the shrinkage factor represents the rate of reduction in molecular size and does not accurately represent the branched structure of the polymer.

[0242] Therefore, the branching degree (Bn) of the conjugated diene polymer is calculated using the value of the shrinkage factor (g') at each absolute molecular weight of the conjugated diene polymer. The calculated "branching degree (Bn)" accurately represents the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.

[0243] The calculated degree of branching (Bn) serves as an indicator of the branching structure of a conjugated diene polymer. For example, in the case of a typical tetrabranched star polymer (where four polymer chains are connected in the center), two arms of the polymer chain are connected to the longest highly branched main chain structure, and the degree of branching (Bn) is evaluated as 2.

[0244] In the case of a typical six-branched star polymer, four arms of the polymer chain are bonded to the longest high-branched main chain structure, and the degree of branching (Bn) is evaluated to be 4.

[0245] The conjugated diene polymer of the present embodiment preferably has a branching degree (Bn) of 1.1 or more and less than 4.0, but in this case, it means a conjugated diene polymer having a branching similar to a star-shaped polymer structure with less than 6 branches from a straight chain.

[0246] Here, "branching" refers to the formation of a polymer by directly or indirectly bonding to another polymer. Also, "branching degree (Bn)" is the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.

[0247] By having a branching degree (Bn) of 1.1 or more and less than 4.0, the modified conjugated diene polymer in this embodiment suppresses cold flow of the bale, which is the product form of the conjugated diene copolymer, while improving interaction with the filler, and tends to have excellent fuel efficiency and kinetic magnification when vulcanized.

[0248] In the present embodiment, the degree of branching (Bn) of the modified conjugated diene polymer is 1.1 or higher and less than 4.0, preferably 1.2 or higher and less than 3.9, more preferably 1.3 or higher and less than 3.8, and even more preferably 1.4 or higher and less than 3.7. Conjugated diene polymers with a degree of branching (Bn) in this range tend to have excellent fuel efficiency and kinetic magnification when vulcanized.

[0249] The degree of branching of the modified conjugated diene polymer can be controlled to be 1.1 or higher and less than 4.0 by a combination of the amount of branching agent added and the amount of terminal modifying agent added. Specifically, the degree of branching can be controlled by the number of functional groups of the branching agent, the amount of branching agent added, the timing of the addition of the branching agent, and the number of functional groups and the amount of nitrogen atom-containing modifying agent added.

[0250] (Molecular weight distribution)

[0251] The modified conjugated diene polymer in the present embodiment has (6) a chromatographic shape measured by a gel permeation chromatograph (GPC) that is monomodal and has a molecular weight distribution of 1.60 to 3.00. Specifically, the modified conjugated diene polymer in the present embodiment has a chromatographic shape measured by a gel permeation chromatograph (GPC) that is monomodal. A chromatographic shape that is monomodal means that the chromatographic shape of the gel permeation chromatograph (GPC) measured by the method described in the following examples indicates that there is only one peak originating from the polymer and that there is no valley in the peak shape.

[0252] Control of the GPC chromatographic profile of a modified conjugated diene polymer can be achieved, for example, by using a continuous polymerization method and appropriately controlling the type and amount of branching agent in the branching process and the type and amount of terminal modifying agent in the modification process.

[0253] More specifically, this can be achieved by the method described in the embodiments below.

[0254] The modified conjugated diene polymer in this embodiment has a molecular weight distribution (Mw / Mn) represented by the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), which is 1.60 or higher and 3.00 or lower.

[0255] Conjugated diene polymers with a molecular weight distribution in this range tend to have excellent wear resistance and fracture strength when a composition incorporating fillers, etc., is vulcanized. The molecular weight distribution described above is more preferably 1.65 or higher and 2.70 or lower, and even more preferably 1.70 or higher and 2.50 or lower.

[0256] The number average molecular weight, weight average molecular weight, and molecular weight distribution of the modified conjugated diene polymer can be measured by the method described in the examples below. The number average molecular weight, weight average molecular weight, and molecular weight distribution of the conjugated diene polymer can be controlled to the above-described range by controlling conditions, for example, such as temperature conditions during the polymerization process, or by adjusting the degree of branching during the branching process.

[0257] The modified conjugated diene polymer in this embodiment has a hydrogenation rate of less than 10 mol% (7). The hydrogenation rate in this embodiment is the hydrogenation rate for double bonds in structural units derived from conjugated diene compounds in the modified conjugated diene polymer.

[0258] Modified conjugated diene polymers in this range of hydrogenation rates tend to have high phase separation when combined with other rubber components, such as natural rubber, and excellent dispersibility of the filler when combined with a filler, as the effect of the terminal modifier is exerted.

[0259] In this regard, a more desirable hydrogen addition rate is less than 5 mol%, more preferably less than 3 mol%, and a non-hydrogen addition form is even more desirable.

[0260] The hydrogenation rate of modified conjugated diene polymers is a nuclear magnetic resonance device ( 1 Using H-NMR, it can be measured by the method described in the following examples.

[0261] In order to keep the hydrogenation rate within the aforementioned range, it can be controlled by appropriately controlling conditions such as the amount of hydrogen added to the double bond in the structural unit derived from the conjugated diene compound, the amount of hydrogenation catalyst in the hydrogenation reaction, hydrogen pressure, reaction temperature, and reaction time. More specifically, this is described in the examples to be described later.

[0262] [1,2 Vinyl binding amount]

[0263] In the present embodiment, the 1,2-vinyl bond content of the modified conjugated diene polymer is preferably 25 mol% or less, more preferably 23 mol% or less, even more preferably 22 mol% or less, and even more preferably 20 mol% or less.

[0264] 1,2 The lower limit of the vinyl binding amount is not particularly limited, but more preferably 7 mol% or more, even more preferably 10 mol% or more, and even more preferably 12 mol% or more.

[0265] 1,2 Examples of combinations of upper and lower limits of vinyl binding amount are not particularly limited, but 10 mol% or more and 25 mol% or less is preferred, 10 mol% or more and 25 mol% or less is preferred, and 12 mol% or more and 22 mol% or less is more preferred.

[0266] The microstructure of the modified conjugated diene polymer can be measured using a Fourier transform infrared spectrophotometer by the method described in the examples below.

[0267] In order to keep the 1,2-vinyl bonding amount within the aforementioned specific range, it can be controlled by the amount of polar material added during the polymerization process. When the amount of polar compound added increases, in addition to increasing the 1,2-vinyl bonding amount, it is also effective in promoting the polymerization reaction; however, when the composition is formulated with fillers, the fracture strength and wear resistance tend to deteriorate, so it is necessary to control the 1,2-vinyl bonding amount within a specific range by adjusting the amount of polar material added. More specifically, this is described in the examples to be described later.

[0268] [Amount of aromatic vinyl binding]

[0269] In the present embodiment, the aromatic vinyl bond amount of the modified conjugated diene polymer is preferably 0 mass% or more and 10 mass% or less. The upper limit of the aromatic vinyl bond amount of the conjugated diene polymer, which is more preferably 7 mass% or less, more preferably 6 mass% or less, and even more preferably 5 mass% or less.

[0270] The amount of aromatic vinyl bonding can be controlled by adjusting the addition ratio of the conjugated diene monomer and the aromatic vinyl compound in the aforementioned polymerization process. More specifically, this is described in the examples below.

[0271] The amount of aromatic vinyl bonds in a conjugated diene polymer can be measured using an ultraviolet spectrophotometer by the method described in the examples below.

[0272] By setting the amount of aromatic vinyl bonding to a specific range, the fracture strength and wear resistance tend to improve when the composition is formulated with fillers, etc.

[0273] [Glass Transition Temperature (Tg)]

[0274] The glass transition temperature of the conjugated diene polymer of the present embodiment is preferably within the range of -110°C to -80°C. A more preferred lower limit of the glass transition temperature of the conjugated diene polymer is -105°C or higher, more preferably -103°C or higher, and even more preferably -100°C or higher.

[0275] In addition, the upper limit of the more desirable glass transition temperature is -82°C or lower, more preferably -84°C or lower, and even more preferably -86°C or lower.

[0276] The glass transition temperature tends to increase as the aforementioned 1,2-vinyl bond amount and aromatic vinyl bond amount increase, and can be controlled by controlling the 1,2-vinyl bond amount and aromatic vinyl bond amount to an appropriate range. More specifically, this is described in the examples to be described later.

[0277] The glass transition temperature of a conjugated diene polymer can be measured using a differential scanning calorimeter (DSC) by the method described in the examples below.

[0278] By setting the glass transition temperature to a specific range, the fracture strength and wear resistance tend to improve when the composition is formulated with fillers, etc.

[0279] [Degeneration Rate]

[0280] In the present embodiment, the modified conjugated diene polymer preferably has a modification rate of 40 mass% or more. Although the term "modification rate" may be used in this specification, "modification rate" refers to the mass ratio of the conjugated diene polymer having nitrogen atom-containing functional groups to the total amount of the conjugated diene polymer.

[0281] The denaturation rate can be measured by chromatography capable of separating the denatured component containing functional groups from the non-denatured component.

[0282] As a method using this chromatography, a method of quantifying by using a column for gel permeation chromatography packed with a polar material such as silica that adsorbs specific functional groups and using an internal standard of non-adsorbed components for comparison (column adsorption GPC method) can be cited.

[0283] More specifically, the denaturation rate is obtained by measuring the amount of adsorption to the silica column from the difference between the chromatogram measured by a polystyrene-based gel column and the chromatogram measured by a silica-based column, of a sample solution containing the sample and a low molecular weight internal standard polystyrene.

[0284] More specifically, the denaturation rate can be measured by the method described in the example.

[0285] In the modified conjugated diene polymer of the present embodiment, the modification rate can be controlled by adjusting the amount of modification agent added and the reaction method, and thereby the modification rate can be controlled to 40 mass% or more.

[0286] [Branch Structure]

[0287] In the present embodiment, the modified conjugated diene polymer has a main chain branching structure having a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and it is preferable that the portion derived from the vinyl monomer containing the alkoxysilyl group or the halosyl group has the branching structure. Specifically, in the present embodiment, the modified conjugated diene polymer has a portion of the polymer chain derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and it is preferable that the portion derived from the vinyl monomer containing the alkoxysilyl group or the halosyl group has a branching structure.

[0288] The branched structure is preferably at least one branch point, at least three branch points, and more preferably at least four branch points at the branch point in the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosyl group.

[0289] In addition, it is preferable that the branching points forming the branched structure have at least one polymer chain, more preferably have two or more polymer chains that are not the main chain, and even more preferably have four or more polymer chains that are not the main chain.

[0290] In particular, in branched structures containing vinyl monomers including alkoxysilyl groups or halosyl groups, when signal detection is performed using 29Si-NMR, peaks originating from the branched structure are detected in the range of -45 ppm to -65 ppm, and more specifically in the range of -50 ppm to -60 ppm.

[0291] In a preferred embodiment of the conjugated diene polymer of the present embodiment, the ends of the polymer chain are modified by a modifying agent containing a nitrogen atom, and a portion of the polymer chain has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and a method for obtaining a modified conjugated diene polymer having an additional branched structure in the portion derived from the vinyl monomer containing the alkoxysilyl group or a halosyl group can be formed by adjusting the number of functional groups and the amount added of the modifying agent containing a nitrogen atom, and the branched structure can be controlled by adjusting the number of functional groups of the branching agent, the amount added of the branching agent, and the timing of the addition of the branching agent. That is, in this specification, the term “part derived from a vinyl monomer” refers to a structure in which the alkoxy group and / or halogen of the vinyl monomer, which is the branching agent described below, becomes a detachable group, and the polymerization active end is substituted, and a polymer chain is bonded to the silicon of vinylsilane, and the vinyl group of vinylsilane is polymerized as an aromatic vinyl compound. When a vinyl monomer containing multiple alkoxy groups and / or halogens is used as the branching agent, multiple polymer chains may be bonded to the silicon of vinylsilane in the “part derived from a vinyl monomer” obtained.

[0292] In order to obtain a conjugated diene polymer having a portion of the polymer chain derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and having an additional branched structure in the portion derived from the vinyl monomer containing the alkoxysilyl group or halosyl group, for example, a method may be used in which an organolithium compound is used as a polymerization initiator, polymerization is carried out, a branching agent that additionally imparts a specific branching point is added during or after polymerization, and after continuing the polymerization, a modifying agent that imparts a specific branching rate is used to modify it.

[0293] [Branchized agent structure]

[0294] In the present embodiment, the modified conjugated diene polymer is preferably a monomer unit derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group as described above, and has a branching point of a polymer chain derived from a monomer unit derived from a compound represented by the following formula (3) or (4), and is more preferably a conjugated diene polymer obtained using a branching agent described later, and is even more preferably a modified conjugated diene polymer in which at least one end of the conjugated diene polymer is modified with a modifying agent having an amino group and an amide group.

[0295]

[0296] During the meal, R 1 It represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure on silver, hydrogen atoms, or a part thereof, and

[0297] R 2 to R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a part thereof, and

[0298] R in the case where multiple exist 1 to R 3 Each is independent.

[0299] X 1 Silver represents an independent halogen atom,

[0300] m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, and (m+n+l) is 3.

[0301]

[0302] During the meal, R 2 to R 5Each represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a part thereof, and R in the case where multiple groups exist. 2 to R 5 are, each independent, and

[0303] X 2 To X 3 Each represents an independent halogen atom, and

[0304] m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, (m+n+l) is 3, and

[0305] a represents an integer from 0 to 2, b represents an integer from 0 to 3, c represents an integer from 0 to 3, and (a+b+c) is 3.

[0306] The branching agent represented by formula (3) is not particularly limited, but, for example, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, tributoxy(2-vinylphenyl)silane, triisopropoxy(2-vinylphenyl)silane, Dimethoxymethyl(4-vinylphenyl)silane, diethoxymethyl(4-vinylphenyl)silane, dipropoxymethyl(4-vinylphenyl)silane, dibutoxymethyl(4-vinylphenyl)silane, diisopropoxymethyl(4-vinylphenyl)silane, dimethoxymethyl(3-vinylphenyl)silane, diethoxymethyl(3-vinylphenyl)silane, dipropoxymethyl(3-vinylphenyl)silane, dibutoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, dimethoxymethyl(2-vinylphenyl)silane, diethoxymethyl(2-vinylphenyl)silane, dipropoxymethyl(2-vinylphenyl)silane, dibutoxymethyl(2-vinylphenyl)silane, diisopropoxymethyl(2-vinylphenyl)silane, dimethylmethoxy(4-vinylphenyl)silane, Dimethyl ethoxy(4-vinylphenyl) silane, dimethyl propoxy(4-vinylphenyl) silane, dimethyl butoxy(4-vinylphenyl) silane, dimethyl isopropoxy(4-vinylphenyl) silane, dimethyl methoxy(3-vinylphenyl) silane, dimethyl ethoxy(3-vinylphenyl) silane, dimethyl propoxy(3-vinylphenyl) silane, dimethyl butoxy(3-vinylphenyl) silane, dimethyl isopropoxy(3-vinylphenyl) silane, dimethyl methoxy(2-vinylphenyl) silane, dimethyl ethoxy(2-vinylphenyl) silane, dimethyl propoxy(2-vinylphenyl) silane, dimethyl butoxy(2-vinylphenyl) silane, dimethyl isopropoxy(2-vinylphenyl) silane, trimethoxy(4-isopropenylphenyl) silane, Triethoxy(4-isopropenphenyl)silane, Tripropoxy(4-isopropenphenyl)silane, Tributoxy(4-isopropenphenyl)silane, Triisopropoxy(4-isopropenphenyl)silane,Trimethoxy(3-isopropenphenyl)silane, Triethoxy(3-isopropenphenyl)silane, Tripropoxy(3-isopropenphenyl)silane, Tributoxy(3-isopropenphenyl)silane, Triisopropoxy(3-isopropenphenyl)silane, Trimethoxy(2-isopropenphenyl)silane, Triethoxy(2-isopropenphenyl)silane, Tripropoxy(2-isopropenphenyl)silane, Tributoxy(2-isopropenphenyl)silane, Triisopropoxy(2-isopropenphenyl)silane, Triisopropoxy(2-isopropenphenyl)silane, Dimethoxymethyl(4-isopropenphenyl)silane, Diethoxymethyl(4-isopropenphenyl)silane, Dipropoxymethyl(4-isopropenphenyl)silane, Dibutoxymethyl(4-isopropenphenyl)silane, Diisopropoxymethyl(4-isopropenphenyl)silane, dimethoxymethyl(3-isopropenphenyl)silane, diethoxymethyl(3-isopropenphenyl)silane, dipropoxymethyl(3-isopropenphenyl)silane, dibutoxymethyl(3-isopropenphenyl)silane, diisopropoxymethyl(3-isopropenphenyl)silane, dimethoxymethyl(2-isopropenphenyl)silane, diethoxymethyl(2-isopropenphenyl)silane, dipropoxymethyl(2-isopropenphenyl)silane, dibutoxymethyl(2-isopropenphenyl)silane, diisopropoxymethyl(2-isopropenphenyl)silane, dimethylmethoxy(4-isopropenphenyl)silane, dimethylethoxy(4-isopropenphenyl)silane, dimethylpropoxy(4-isopropenphenyl)silane, Dimethylbutoxy(4-isopropenphenyl)silane, dimethylisopropoxy(4-isopropenphenyl)silane, dimethylmethoxy(3-isopropenphenyl)silane, dimethylethoxy(3-isopropenphenyl)silane, dimethylpropoxy(3-isopropenphenyl)silane, dimethylbutoxy(3-isopropenphenyl)silane, dimethylisopropoxy(3-isopropenphenyl)silane, dimethylisopropoxy(3-isopropenphenyl)silane, dimethylmethoxy(2-isopropenphenyl)silane, dimethylethoxy(2-isopropenphenyl)silane, dimethylpropoxy(2-isopropenphenyl)silane, dimethylbutoxy(2-isopropenphenyl)silane, dimethylisopropoxy(2-isopropenphenyl)silane, trichloro(4-vinylphenyl)silane, trichloro(3-vinylphenyl)silane, Trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane,Examples include tribromo(2-vinylphenyl)silane, dichloromethyl(4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl(2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo(3-vinylphenyl)silane, and dimethylbromo(2-vinylphenyl)silane.

[0307] Among these, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, and trichloro(4-vinylphenyl)silane are preferred, and trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, and tributoxy(4-vinylphenyl)silane are more preferred.

[0308] The branching agent represented by formula (4) is not particularly limited, but examples include 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-triethoxysilylphenyl)ethylene, 1,1-bis(3-tripropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(3-triisopropoxysilylphenyl)ethylene, 1,1-bis(2-trimethoxysilylphenyl)ethylene, 1,1-Bis(2-triethoxysilylphenyl)ethylene, 1,1-Bis(3-tripropoxysilylphenyl)ethylene, 1,1-Bis(2-tripentoxysilylphenyl)ethylene, 1,1-Bis(2-triisopropoxysilylphenyl)ethylene, 1,1-Bis(4-(dimethylmethoxysilyl)phenyl)ethylene, 1,1-Bis(4-(diethylmethoxysilyl)phenyl)ethylene, 1,1-Bis(4-(dipropylmethoxysilyl)phenyl)ethylene, 1,1-Bis(4-(dimethylethoxysilyl)phenyl)ethylene, 1,1-Bis(4-(diethylethoxysilyl)phenyl)ethylene and 1,1-Bis(4-(dipropylethoxysilyl)phenyl)ethylene, 1,1-Bis(4-(methyldimethoxysilyl)phenyl)ethylene, Examples include 1,1-bis(4-(ethyldiethoxysilyl)phenyl)ethylene.

[0309] Among these, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene are preferred, and 1,1-bis(4-trimethoxysilylphenyl)ethylene is more preferred.

[0310] The modified conjugated diene polymer in this embodiment has a main chain branching structure having monomer units derived from the compound represented by the above-described formula (3), and in formula (3), R 1It is desirable to represent this hydrogen atom and for m to represent 0. By doing so, the branching index is improved, and while the cold flow of the bale, which is the product form of the conjugated diene polymer, is suppressed, the processability when vulcanized is extremely excellent, and the effect of excellent wear resistance and fracture strength when vulcanized is obtained.

[0311] In the present embodiment, the modified conjugated diene polymer has a main chain branching structure having monomer units derived from the compound represented by the above-described formula (4), and in formula (4), it is preferable that m represents 0 and b represents 0. By doing so, an effect of improving wear resistance and processability is obtained.

[0312] The modified conjugated diene polymer in this embodiment has a main chain branching structure having monomer units derived from a compound represented by the above-described formula (3), wherein R in formula (3) 1 It is more preferable that this hydrogen atom is represented, m is represented as 0, n is represented as 3, and l is represented as 0. By doing so, the modification rate and branching degree are improved, and while suppressing the cold flow of the bale, which is the product form of the conjugated diene polymer, the effects of improved fuel efficiency, wear resistance, and processability are obtained.

[0313] In the present embodiment, the modified conjugated diene polymer has a main chain branching structure that has monomer units derived from the compound represented by the above-described formula (4), and in formula (4), it is preferable that m represents 0, n represents 3, l represents 0, a represents 0, b represents 0, and c represents 3. By doing so, the effect of improving wear resistance and processability is obtained while suppressing the cold flow of the bale, which is the product form of the conjugated diene polymer.

[0314] Rubber composition, vulcanized rubber composition

[0315] The rubber composition of the present embodiment can be made into a vulcanized rubber composition by vulcanizing. In other words, the vulcanized rubber composition of the present embodiment is a composition obtained by vulcanizing a rubber composition comprising a modified conjugated diene polymer.

[0316] (Silanic coupling agent)

[0317] The rubber composition of the present embodiment may include a silane coupling agent when silica is incorporated as a filler. The silane coupling agent has the function of closely coordinating the interaction between the rubber component and the inorganic filler, has a group having affinity or bonding properties for each of the rubber component and the silica-based inorganic filler, and is preferably a compound having a sulfur bonding portion and an alkoxysilyl group or a silanol group portion in one molecule. Examples of such compounds are not particularly limited, but include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0318] In the rubber composition of the present embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the silica-based inorganic filler described above, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 parts by mass or more and 15 parts by mass or less. If the content of the silane coupling agent is within the range described above, the additive effect described above by the silane coupling agent tends to be made more pronounced.

[0319] (Rubber softener)

[0320] The rubber composition of the present embodiment may include a rubber softener in order to improve its processability.

[0321] The amount of rubber softener added is represented by the amount of rubber softener contained in the aforementioned conjugated diene polymer or other rubbery polymers, and the total amount of rubber softener added when making a cross-linked rubber composition, with respect to 100 parts by mass of the rubber component containing the aforementioned conjugated diene polymer.

[0322] Mineral oil, or liquid or low-molecular-weight synthetic softeners are suitable as rubber softeners.

[0323] Mineral oil-based rubber softeners, referred to as process oils or extender oils, which are used to promote the softening, expansion, and improvement of processability of rubber, are mixtures of aromatic rings, naphthenic rings, and paraffin chains. Those in which the number of carbon atoms in the paraffin chains accounts for 50% or more of the total carbons are called paraffinic, those in which the number of carbon atoms in the naphthenic rings accounts for 30% or more and 45% or less of the total carbons are called naphthenic, and those in which the number of carbon atoms in the aromatic rings accounts for more than 30% of the total carbons are called aromatic. When the conjugated diene polymer of the present embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, it is preferable for the rubber softener used to have an appropriate aromatic content, as this tends to have good affinity with the copolymer.

[0324] In the rubber composition of the present embodiment, the content of the rubber softener is preferably 0 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the rubber component, more preferably 5 parts by mass or more and 90 parts by mass or less, and even more preferably 10 parts by mass or more and 80 parts by mass or less. By having a content of the rubber softener of 100 parts by mass or less with respect to 100 parts by mass of the rubber component, bleed-out is suppressed and stickiness on the surface of the rubber composition tends to be suppressed.

[0325] (Method for manufacturing a rubber composition)

[0326] The method for manufacturing the rubber composition of the present embodiment is not particularly limited, but may include, for example, a method of melt-kneading additives such as conjugated diene polymers, other rubbery polymers, carbon black, silica-based inorganic fillers or other fillers, silane coupling agents, and rubber softeners using a general mixer such as an open roll, Banbury mixer, kneader, single-screw extruder, twin-screw extruder, or multi-screw extruder, or a method of removing the solvent by heating after melting and mixing each component. Among these, the melt-kneading method using a roll, Banbury mixer, kneader, or extruder is preferred in terms of productivity and good mixability. In addition, both a method of mixing the rubber components, other fillers, silane coupling agents, and additives in one step and a method of mixing in multiple steps are applicable.

[0327] The rubber composition of the present embodiment may be a vulcanized rubber composition (hereinafter also referred to as a "vulcanized composition") that has undergone vulcanization treatment with a vulcanizing agent. As a vulcanizing agent, it is not particularly limited, but examples include radical generating agents such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric polysulfide compounds, etc. In the rubber composition of the present embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component, and more preferably 0.1 parts by mass or more and 15 parts by mass or less. As a vulcanization method, a conventionally known method may be applied, and the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.

[0328] During vulcanization, a vulcanization accelerator may be used as needed. As a vulcanization accelerator, conventionally known materials may be used and are not particularly limited, but examples include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Additionally, as a vulcanization aid, there are no particularly limited examples, but zinc oxide and stearic acid may be used. The content of the vulcanization accelerator is preferably 0.01 parts by weight or more and 20 parts by weight or less per 100 parts by weight of the rubber component, and more preferably 0.1 parts by weight or more and 15 parts by weight or less.

[0329] In the rubber composition of the present embodiment, various additives other than those described above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, may be used to the extent that the purpose of the present invention is not impaired. As other softeners, known softeners may be used. As other fillers, specifically, although not particularly limited, examples include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. As the heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants described above, known materials may be used for each.

[0330] The rubber composition of the present embodiment is suitably used as a rubber composition for tires. That is, the tire of the present embodiment contains the rubber composition of the present embodiment or the vulcanized rubber composition.

[0331] The rubber composition for tires is not particularly limited, but can be used for various parts of tires such as fuel-efficient tires, all-season tires, high-performance tires, studless tires, and tires for heavy-duty vehicles, such as treads, carcasses, sidewalls, and bead sections. In particular, the rubber composition for tires is suitable for use as treads for fuel-efficient tires, high-performance tires, and tires for heavy-duty vehicles because, when vulcanized, it has an excellent balance of wear resistance, fracture strength, low hysteresis loss, and wet skid resistance.

[0332] In addition, the rubber composition of the present embodiment has industrial applicability as, in addition to tires, anti-vibration rubber, vibration-isolating rubber, conveyor belts, shoe soles such as outsoles for shoes, weather strips for automobiles, packing or gaskets, sealing materials, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary supplies, hoses for industrial and various uses, battery cases, adhesives, wire insulation, window frame rubber, rubber plugs, rubber rollers, and materials for various industrial products.

[0333] Examples

[0334] The present embodiment will be described in more detail below with reference to specific examples and comparative examples, but the present embodiment is not limited in any way by the following examples and comparative examples.

[0335] Various physical properties in the examples and comparative examples were measured by the method shown below.

[0336] (Physical Property 1) Mooney Viscosity

[0337] A conjugated diene polymer (before modification) or a conjugated diene polymer modified with a substituted amino group-containing modifying agent (hereinafter also referred to as "modified conjugated diene polymer" and together with the conjugated diene polymer as "(modified) conjugated diene polymer") was used as a sample, and Mooney viscosity was measured using an L-type rotor in accordance with ISO 289 using a Mooney viscometer (product name "VR1132" manufactured by Seisakusho Uejima).

[0338] The measurement temperature was set to 100℃.

[0339] First, the sample was preheated at the test temperature for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured and called the Mooney viscosity (ML (physical property 1)). In addition, Table 1 shows the measurement results of the Mooney viscosity before modification (100°C) and the Mooney viscosity after modification (100°C).

[0340] (Physical Property 2) Microstructure of Conjugated Diene Polymers (1,2 Vinyl Bond Amount)

[0341] In the case of polybutadiene, the (modified) conjugated diene polymer was used as the sample, and 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare the measurement sample. Using a solution cell, the infrared spectrum was measured at 600 to 1000 cm⁻¹. -1 The 1,2-vinyl bond content (mol%) of the conjugated diene polymer was determined by measuring within the range and using the absorbance at a given wavenumber according to the formula of Morero's method (the method described in D. Morero, A. Santambrogio, L. Porri, F. Clampelli: Chim. e Ind., 41, 758 (1959)) (measuring device: Fourier transform infrared spectrophotometer "FT-IR" manufactured by Nihon Bunko Co., Ltd. 2 30」).

[0342] In the case of a (modified) conjugated diene polymer, specifically a styrene-butadiene copolymer, measurements were taken in the same manner as in the case of the aforementioned polybutadiene, and the microstructure of the butadiene portion, i.e., the amount of 1,2-vinyl bonds (mol%), was determined according to the calculation formula of Hampton's method (the method described in RR Hampton, Analytical Chemistry 21, 923 (1949)) based on the absorbance at a predetermined wavenumber.

[0343] (Physical Property 3) Amount of bound styrene (Amount of styrene; Amount of aromatic vinyl bound)

[0344] A (modified) conjugated diene polymer was used as a sample, and 100 mg of the sample was mixed with 100 mL of chloroform and dissolved to form a measurement sample. The amount of bound styrene (mass%) relative to 100 mass% of the modified conjugated diene polymer sample was measured based on the amount of absorption of ultraviolet light at the wavelength (around 254 nm) by the phenyl group of styrene (spectrophotometer "UV-2450" manufactured by Shimadzu Seisakusho Co., Ltd.).

[0345] (Physical Property 4) Glass Transition Temperature

[0346] A (modified) conjugated diene polymer was used as a sample, and DSC measurements were performed using a differential scanning calorimeter (NETZSCH “DSC3500”) in accordance with ISO 22768:2006. DSC curves were recorded while increasing the temperature from -130°C at 20°C / min under a flow of 50 mL / min of helium, and the inflection point of the DSC differential curve was set as the glass transition temperature (Tg).

[0347] (Physical Property 5) Branching Degree (Bn)

[0348] The branching degree (Bn) of the (modified) conjugated diene polymer was measured as follows by the GPC-light scattering method equipped with a viscosity detector. Using the (modified) conjugated diene polymer as a sample, a gel permeation chromatography (GPC) measuring device (product name “GPCmax VE-2001”) with three columns connected with polystyrene-based gel as a filler was used to measure using three detectors connected in the order of a light scattering detector, an RI detector, and a viscosity detector (product name “TDA305”). Based on standard polystyrene, the absolute molecular weight was obtained from the results of the light scattering detector and the RI detector, and the intrinsic viscosity was obtained from the results of the RI detector and the viscosity detector.

[0349] Linear polymers have an intrinsic viscosity [η]=10 -3.883 ×M 0.771 Using the formula, the shrinkage factor (g') was calculated as the ratio of intrinsic viscosity corresponding to each molecular weight. In addition, in the formula, M represents the absolute molecular weight.

[0350] Subsequently, using the obtained contraction factor (g'), the branching degree (Bn) was calculated, defined as g'=6Bn / {(Bn+1)(Bn+2)}.

[0351] The eluent used was tetrahydrofuran containing 5 mmol / L of triethylamine (hereinafter also referred to as “THF”).

[0352] The column used the product names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Dososa.

[0353] 20 mg of the sample for measurement was dissolved in 10 mL of THF to make the measurement solution, and 100 μL of the measurement solution was injected into a GPC measuring device and measured under conditions of an oven temperature of 40°C and a THF flow rate of 1 mL / min.

[0354] (Physical Property 6) Molecular Weight (Weight Average Molecular Weight, Number Average Molecular Weight, Mw / Mn)

[0355] Measurement condition 1: (Modified) conjugated diene polymer was used as a sample, and a GPC measuring device (product name “HLC-8320GPC”) with three columns packed with polystyrene gel was used, and a chromatogram was measured using an RI detector (product name “HLC8020”). Based on the calibration curve obtained using standard polystyrene, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined.

[0356] The eluent used was THF (tetrahydrofuran) containing 5 mmol / L of triethylamine. Three columns of the Toso brand “TSKgel SuperMultipore HZ-H” were connected, and a Toso brand “TSKguardcolumn SuperMP(HZ)-H” was connected as a guard column in front of them.

[0357] 10 mg of the sample for measurement was dissolved in 10 mL of THF to make the measurement solution, and 10 μL of the measurement solution was injected into a GPC measuring device and measured under conditions of an oven temperature of 40°C and a THF flow rate of 0.35 mL / min.

[0358] Among the various samples measured under the above-described measurement condition 1, samples in which the molecular weight distribution (Mw / Mn) value was less than 1.6 were measured again under the following measurement condition 2. For samples measured under measurement condition 1 in which the molecular weight distribution value was 1.6 or higher, the value measured under measurement condition 1 was used.

[0359] Measurement condition 2: A conjugated diene polymer or a coupling conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC measuring device with three columns connected with polystyrene gel as a filler, and the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were determined based on a calibration curve using standard polystyrene.

[0360] The eluent used was THF containing 5 mmol / L of triethylamine. The columns used were: guard column: TSKguardcolumn SuperH-H manufactured by Dosoh Co., Ltd., and columns: TSKgel SuperH5000, TSKgel SuperH6000, and TSKgel SuperH7000 manufactured by Dosoh Co., Ltd.

[0361] Under conditions of an oven temperature of 40℃ and a THF flow rate of 0.6 mL / min, an RI detector (product name “HLC8020” manufactured by Tosho Co., Ltd.) was used. 10 mg of the sample to be measured was dissolved in 20 mL of THF to make the measurement solution, and 20 μL of the measurement solution was injected into a GPC measuring device for measurement.

[0362] (Physical Property 7) Modification Rate

[0363] (Modification) The modification rate in conjugated diene polymers was measured as follows using the column adsorption GPC method. A coupling conjugated diene polymer was used as a sample, and the measurement was performed by applying the characteristic of adsorbing modified basic polymer components onto a GPC column packed with silica gel.

[0364] The modification rate was calculated by measuring the amount of adsorption to the silica column from the difference between the chromatogram measured by the polystyrene-based column and the chromatogram measured by the silica-based column for a sample solution containing the sample and low molecular weight internal standard polystyrene.

[0365] Specifically, as shown below. In addition, for samples in which the molecular weight distribution value was 1.6 or higher when measured under measurement condition 1 of the above-described (physical property 4), the following measurement condition 3 was applied, and for samples in which the molecular weight distribution value was less than 1.6, the following measurement condition 4 was applied.

[0366] Preparation of sample solution: 10 mg of sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to make the sample solution.

[0367] Measurement Condition 3: GPC measurement condition using a polystyrene-based column:

[0368] Using the Tosho Corporation product name “HLC-8320GPC”, 10 μL of sample solution was injected into the device using THF containing 5 mmol / L of triethylamine as the eluent, and a chromatogram was obtained using an RI detector under conditions of a column oven temperature of 40°C and a THF flow rate of 0.35 mL / min. Three Tosho Corporation product names “TSKgel SuperMultiporeHZ-H” columns were connected, and a Tosho Corporation product name “TSKguardcolumn SuperMP(HZ)-H” was connected upstream as a guard column.

[0369] Measurement Condition 4: THF containing 5 mmol / L of triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. The columns used were: Guard column: Tosoh Co., Ltd. trade name "TSKguardcolumn SuperH-H"; and Columns: Tosoh Co., Ltd. trade names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000". Under conditions of a column oven temperature of 40°C and a THF flow rate of 0.6 mL / min, measurements were taken using an RI detector (Tosoh Co., Ltd. HLC8020) to obtain a chromatogram.

[0370] GPC measurement conditions using a silica-based column: Using the product name “HLC-8320GPC” manufactured by Tosho Co., Ltd., THF was used as the eluent, 50 μL of the sample solution was injected into the device, and a chromatogram was obtained using an RI detector under conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were the product names “Zorbax PSM-1000S”, “PSM-300S”, and “PSM-60S”, and the product name “DIOL 4.6×12.5㎜ 5micron” was connected as a guard column upstream thereof.

[0371] Method for calculating the modification rate: The total peak area of ​​the chromatogram using a polystyrene-based column was set to 100, the peak area of ​​the sample was set to P1, the peak area of ​​the standard polystyrene was set to P2, the total peak area of ​​the chromatogram using a silica-based column was set to 100, the peak area of ​​the sample was set to P3, and the peak area of ​​the standard polystyrene was set to P4, and the modification rate (%) was calculated from the following formula.

[0372] Modification Rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100

[0373] (where P1+P2=P3+P4=100)

[0374] (Physical Property 8) Hydrogenation Rate

[0375] A (modified) conjugated diene polymer not containing antioxidants was used as a sample, and 50 mg of the sample was dissolved in 1 mL of deuterated chloroform to serve as the measurement sample. Nuclear magnetic resonance apparatus ( 1 Measurements were performed using an H-NMR (product name “JNM-LA400” manufactured by JEOL) under conditions of an observation frequency of 400 MHz, a pulse delay of 2.904 seconds, 64 integration cycles, a pulse width of 45°, and a measurement temperature of 26°, and the hydrogenation rate of double bonds in structural units derived from 1,3-butadiene was calculated from the composition ratio (mol%) of 1,4 bond structural units, 1,2 bond structural units, hydrogenated 1,4 bond structural units, and hydrogenated 1,2 bond structural units derived from 1,3-butadiene using TMS (tetramethylsilane) as a reference material.

[0376] (Synthesization Example 1) Modified conjugated diene polymer (Sample 1)

[0377] Two molding pressure vessels having a volume of 10L, a ratio of internal height (L) to diameter (D) of 4.0 (L / D), an inlet at the bottom and an outlet at the top, and a stirring-attached molding reactor having a stirring device and a temperature control jacket were connected as polymerization reactors.

[0378] 1,3-butadiene, from which moisture had been removed beforehand, was mixed at a rate of 30.8 g / min, and n-hexane at a rate of 189.3 g / min. In a static mixer installed in the piping supplying this mixed solution to the inlet of the reactor, n-butyllithium for inert treatment of residual impurities was added and mixed at a rate of 0.072 mmol / min, and then continuously supplied to the bottom of the reactor. In addition, 2,2-bis(2-oxoranyl)propane as a polar substance at a rate of 0.027 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.205 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the reactor temperature was maintained at 78°C.

[0379] A polymer solution was continuously discharged from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 78°C, and additionally supplied to a static mixer from the top of the second reactor. Once the polymerization was sufficiently stable, while polymerizing 1,3-butadiene, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactor at a rate of 0.030 mmol / min to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a branched structure. Additionally, once the polymerization and branching reactions were stable, a small amount of the conjugated diene polymer solution before the addition of the modifier was discharged, an antioxidant (BHT) was added at a rate of 0.2 g per 100 g of polymer, the solvent was removed, and the Mooney viscosity of the conjugated diene polymer was measured. The measurement results are shown in Table 1.

[0380] Next, 1,3-dimethylimidazolidinone (abbreviated as "A" in the table) was continuously added as a modifying agent to the polymer solution discharged from the outlet of the reactor at a rate of 0.155 mmol / min, mixed using a static mixer, and carried out a modification reaction. At this time, the time until the modifying agent was added to the polymer solution discharged from the outlet of the reactor was 4.8 minutes, the temperature was 76°C, and the difference between the temperature during the polymerization process and the temperature until the addition of the modifying agent was 2°C.

[0381] Next, an antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.055 g / min (n-hexane solution) such that the amount was 0.2 g per 100 g of polymer, thereby terminating the modification reaction. Afterward, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer (Sample 1) having a tetrabranched structure derived from trimethoxy(4-vinylphenyl)silane (a compound represented by Formula (3) described above) in some of the main chains, and various physical properties of the sample were measured. The measurement results are shown in Table 1.

[0382] For the polymer before the addition of the branching agent, the polymer before modification after the addition of the branching agent, and the polymer at each process after the addition of the modification agent, the structure of the modified conjugated diene polymer was identified by comparing the molecular weight measured by GPC with the degree of branching measured by viscometer-attached GPC. Below, the structure of each sample was identified in the same manner.

[0383] (Synthesization Examples 2 to 9) Modified conjugated diene polymers (Samples 2 to 9)

[0384] Modified conjugated diene polymers (Samples 2 to 9) were obtained in the same manner as Synthesis Example 1, except that the manufacturing conditions of Example 1 were changed to the manufacturing conditions of Examples 2 to 9 shown in Table 1. Various physical properties of the samples were measured. The measurement results are shown in Table 1. In the table, “BS-2” to “BS-3” and “B”, indicated as branching agents and modifying agents, respectively represent the following compounds.

[0385] "BS-2": Dimethylmethoxy(4-vinylphenyl)silane

[0386] "BS-3": 1,1-bis(4-(methyldimethoxysilyl)phenyl)ethylene (compound represented by the above-described formula (4))

[0387] 「B」: N-methyl-2-pyrrolidone

[0388] (Preparation of hydrogenation catalysts)

[0389] A molding pressure vessel equipped with a stirrer, having a volume of 5L and a ratio of internal height (L) to diameter (D) of 4.0, was formed by pre-submerging nitrogen.

[0390] To this, 3200 g of cyclohexane, which had been previously purified and dehydrated, was fed into the mixing tank. Subsequently, 250 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While stirring thoroughly, 500 mmol of trimethylaluminum (1.4 mol / L, normal hexane solution) was added, and the mixture was reacted at room temperature for 3 days to obtain a hydrogenation catalyst.

[0391] (Synthesization Example 10) Modified conjugated diene polymer (Sample 10)

[0392] Two molding pressure vessels having a volume of 10L, a ratio of internal height (L) to diameter (D) of 4.0 (L / D), an inlet at the bottom and an outlet at the top, and a stirring-attached molding reactor having a stirring device and a temperature control jacket were connected as polymerization reactors.

[0393] 1,3-butadiene, from which moisture had been removed beforehand, was mixed at a rate of 30.8 g / min, and n-hexane at a rate of 189.3 g / min. In a static mixer installed in the piping supplying this mixed solution to the inlet of the reactor, n-butyllithium for inert treatment of residual impurities was added at a rate of 0.072 mmol / min and mixed, and then continuously supplied to the bottom of the reactor. In addition, 2,2-bis(2-oxoranyl)propane as a polar substance at a rate of 0.027 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.205 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the reactor temperature was maintained at 78°C.

[0394] A polymer solution was continuously discharged from the top of the first reactor and continuously supplied to the bottom of the second reactor, and the reaction was continued at 78°C. Additionally, the solution was supplied to a static mixer from the top of the second reactor. Once the polymerization was sufficiently stable, while polymerizing 1,3-butadiene, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactor at a rate of 0.030 mmol / min to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a branched structure. Furthermore, once the polymerization and branching reactions were stable, a small amount of the conjugated diene polymer solution before the addition of the modifier was discharged. An antioxidant (BHT) was added at a rate of 0.2 g per 100 g of polymer, after which the solvent was removed, and the Mooney viscosity of the conjugated diene polymer was measured. The measurement results are shown in Table 1.

[0395] Next, 1,3-dimethylimidazolidinone (abbreviated as "A" in the table) was continuously added as a modifying agent to the polymer solution discharged from the outlet of the reactor at a rate of 0.155 mmol / min, mixed using a static mixer, and carried out a modification reaction. At this time, the time until the modifying agent was added to the polymer solution discharged from the outlet of the reactor was 4.8 minutes, the temperature was 76°C, and the difference between the temperature during the polymerization process and the temperature until the addition of the modifying agent was 2°C.

[0396] Next, a molded pressure vessel of the same type used as a polymerization reactor was connected as a hydrogenation reactor, and the polymer solution after the modification reaction was continuously supplied to the bottom of the hydrogenation reactor. Additionally, the hydrogenation catalyst synthesized above was continuously added to 100 parts by mass of the conjugated diene polymer at a rate of 30 ppm / min based on titanium atoms and at a rate of 768 ml / min (a hydrogenation rate of 6 mol% for double bonds derived from butadiene in the conjugated diene polymer) to continuously carry out a hydrogenation reaction.

[0397] At this time, the pressure of the hydrogenation reactor was 0.50 MPa, and the temperature inside the reactor was 75°C.

[0398] At a stable point for the hydrogenation reaction, an antioxidant (BHT) was continuously added to the hydrogenated polymer solution at a rate of 0.055 g / min (n-hexane solution) such that the amount was 0.2 g per 100 g of polymer, thereby terminating the hydrogenation reaction. Subsequently, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer (Sample 10) in which a portion of the conjugated diene polymer was hydrogenated and the main chain had a tetrabranched structure derived from trimethoxy(4-vinylphenyl)silane (a compound represented by Formula (3) described above). Various physical properties of the sample were then measured. The measurement results are shown in Table 1.

[0399] (Comparative Synthesis Example 1) Conjugated diene polymer (Sample 11)

[0400] Two molding pressure vessels having a volume of 10L, a ratio of internal height (L) to diameter (D) of 4.0 (L / D), an inlet at the bottom and an outlet at the top, and a stirring-attached molding reactor having a stirring device and a temperature control jacket were connected as polymerization reactors.

[0401] 1,3-butadiene, from which moisture had been removed beforehand, was mixed at a rate of 30.8 g / min, and n-hexane at a rate of 189.3 g / min. In a static mixer installed in the piping supplying this mixed solution to the inlet of the reactor, n-butyllithium for inert treatment of residual impurities was added and mixed at a rate of 0.072 mmol / min, and then continuously supplied to the bottom of the reactor. Additionally, 2,2-bis(2-oxoranyl)propane as a polar substance at a rate of 0.027 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.205 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the reactor temperature was maintained at 78°C.

[0402] A polymer solution was continuously discharged from the top of the first reactor and continuously supplied to the bottom of the second reactor, and the reaction was continued at 78°C. Additionally, the solution was supplied to a static mixer from the top of the second reactor. Once the polymerization reaction was sufficiently stable, a small amount of the conjugated diene polymer solution was discharged. After adding an antioxidant (BHT) at a concentration of 0.2 g per 100 g of polymer, the solvent was removed, and the Mooney viscosity of the conjugated diene polymer was measured. The measurement results are shown in Table 2.

[0403] Next, an antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.055 g / min (n-hexane solution) such that the amount was 0.2 g per 100 g of polymer. Subsequently, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer (Sample 11), and various physical properties were measured. The measurement results are shown in Table 2.

[0404] (Comparative Synthesis Examples 2 and 3) Conjugated diene polymers (Samples 12 and 13)

[0405] From the manufacturing conditions of Comparative Synthesis Example 1, the conditions were changed to those of Comparative Synthesis Examples 2 and 3 shown in Table 2. Once the polymerization reaction was sufficiently stable, a branching agent was added to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a branched structure. Subsequently, conjugated diene polymers (Samples 12 and 13) were obtained in the same manner as Comparative Example 1, except that no modifying agent was added, and various physical properties were measured. The measurement results are shown in Table 2.

[0406] (Comparative Synthesis Example 4) Modified conjugated diene polymer (Sample 14)

[0407] A modified conjugated diene polymer (Sample 14) was obtained in the same manner as Comparative Synthesis Example 1, except that the manufacturing conditions of Comparative Synthesis Example 1 were changed to the manufacturing conditions of Comparative Synthesis Example 4 shown in Table 2, and when the polymerization reaction was sufficiently stable, a modifying agent was added to perform the polymerization and modification reactions to obtain a conjugated diene polymer, and various physical properties were measured. The measurement results are shown in Table 2.

[0408] (Comparative Synthesis Examples 5 and 6) Modified conjugated diene polymers (Samples 15 and 16)

[0409] From the manufacturing conditions of Comparative Synthesis Example 1, the conditions were changed to those of Comparative Synthesis Examples 5 and 6 shown in Table 2. Once the polymerization reaction was sufficiently stable, a branching agent was added, and polymerization and branching reactions were carried out to obtain a conjugated diene polymer having a branched structure. Subsequently, once the polymerization and branching reactions were sufficiently stable, modified conjugated diene polymers (Samples 15 and 16) were obtained in the same manner as Comparative Synthesis Example 1, except that a modifying agent was added, and various physical properties were measured. The measurement results are shown in Table 2. "BS-4", indicated as a branching agent in the table, represents the following compounds.

[0410] "BS-4": 1,1-Bis(4-trimethoxysilylphenyl)ethylene

[0411] (Comparative Synthesis Example 7) Modified conjugated diene polymer (Sample 17)

[0412] A molding pressure vessel equipped with a stirrer and a temperature control jacket, which is a molding reactor with a volume of 10L and a ratio (L / D) of the internal height (L) to the diameter (D) of 4.0, was used as a polymerization reactor.

[0413] 1050 g of 1,3-butadiene and 4780 g of n-hexane, which had been dehydrated beforehand, were fed into a reactor and mixed by stirring. Then, 0.01 mmol of 2,2-bis(2-oxoranyl)propane was added to the reactor as a polar substance, and the temperature of the reactor was controlled to 45°C while continuing to stir.

[0414] After confirming that the internal temperature of the reactor stabilized at 45°C while stirring, the hot water in the reactor jacket was drained, and 10.66 mmol of n-butyllithium was added as a polymerization initiator to start the polymerization reaction. After the polymerization started, the internal temperature of the reactor began to rise slowly and reached 95°C after 21 minutes, reaching peaking.

[0415] 2 minutes after picking, 1.33 mmol of trimethoxy(4-vinylphenyl)silane (abbreviated as “BS-1” in the table) was added as a branching agent and a branching reaction was carried out for 5 minutes. Then, 6.40 mmol of 1,3-dimethylimidazolidinone (abbreviated as “A” in the table) was added as a denaturing agent and a denaturing reaction was carried out for 5 minutes.

[0416] After the denaturation reaction, 10.00 mmol of ethyl alcohol was added to completely stop the reaction.

[0417] Next, an antioxidant (BHT) was added to the polymer solution at a concentration of 0.2 g per 100 g of polymer. Subsequently, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer (Sample 17) containing a tetrahedral structure, and various physical properties of the sample were measured. The measurement results are shown in Table 2.

[0418] (Comparative Synthesis Example 8) Conjugated diene polymer (Sample 18)

[0419] Hysis BR manufactured by UBE Elastomer Co., Ltd., product name “UBEPOL BR150” (Moonie viscosity (100℃): 43, 1,2 vinyl binding amount: 1 mol%) was prepared as (Sample 18).

[0420] (Comparative Synthesis Example 9) Modified conjugated diene polymer (Sample 19)

[0421] The manufacturing conditions of Comparative Synthesis Example 1 were changed to the manufacturing conditions of Comparative Synthesis Example 9 shown in Table 2, and when the polymerization reaction was sufficiently stable, a branching agent was added to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a branched structure. Subsequently, when the polymerization reaction and the branching reaction were sufficiently stable, a modified conjugated diene polymer (Sample 19) was obtained in the same manner as Comparative Synthesis Example 1, except that a modifying agent was added, and various physical properties were measured. The measurement results are shown in Table 2.

[0422] "BS-3" indicated as a branching agent in the table represents the following compounds.

[0423] "BS-3": 1,1-bis(4-(methyldimethoxysilyl)phenyl)ethylene

[0424] (Comparative Synthesis Example 10) Modified conjugated diene polymer (Sample 20)

[0425] Two molding pressure vessels having a volume of 10L, a ratio of internal height (L) to diameter (D) of 4.0 (L / D), an inlet at the bottom and an outlet at the top, and a stirring-attached molding reactor having a stirring device and a temperature control jacket were connected as polymerization reactors.

[0426] 1,3-butadiene, from which moisture had been removed beforehand, was mixed at a rate of 30.8 g / min, and n-hexane at a rate of 189.3 g / min. In a static mixer installed in the piping supplying this mixed solution to the inlet of the reactor, n-butyllithium for inert treatment of residual impurities was added and mixed at a rate of 0.072 mmol / min, and then continuously supplied to the bottom of the reactor. Additionally, 2,2-bis(2-oxoranyl)propane as a polar substance at a rate of 0.027 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.205 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the reactor temperature was maintained at 78°C.

[0427] A polymer solution was continuously discharged from the top of the first reactor and continuously supplied to the bottom of the second reactor, and the reaction was continued at 78°C. Additionally, the solution was supplied to a static mixer from the top of the second reactor. Once the polymerization was sufficiently stable, while polymerizing 1,3-butadiene, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactor at a rate of 0.030 mmol / min to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a branched structure. Additionally, once the polymerization and branching reactions were stable, a small amount of the conjugated diene polymer solution before the addition of the modifier was discharged. An antioxidant (BHT) was added at a rate of 0.2 g per 100 g of polymer, after which the solvent was removed, and the Mooney viscosity of the conjugated diene polymer was measured. The measurement results are shown in Table 2.

[0428] Next, 1,3-dimethylimidazolidinone (abbreviated as "A" in the table) was continuously added as a modifying agent to the polymer solution discharged from the outlet of the reactor at a rate of 0.155 mmol / min, mixed using a static mixer, and carried out a modification reaction. At this time, the time until the modifying agent was added to the polymer solution discharged from the outlet of the reactor was 4.8 minutes, the temperature was 76°C, and the difference between the temperature during the polymerization process and the temperature until the addition of the modifying agent was 2°C.

[0429] Next, a molded pressure vessel of the same type used as a polymerization reactor was connected as a hydrogenation reactor, and the polymer solution after the modification reaction was continuously supplied to the bottom of the hydrogenation reactor. Additionally, the hydrogenation catalyst synthesized above was continuously added to 100 parts by mass of the conjugated diene polymer at a rate of 30 ppm / min based on titanium element and at a rate of 1536 ml / min (the hydrogenation rate for double bonds derived from butadiene in the conjugated diene polymer was equivalent to 12 mol%) to continuously carry out a hydrogenation reaction.

[0430] At this time, the pressure of the hydrogenation reactor was 0.50 MPa, and the temperature inside the reactor was 75°C.

[0431] At a stable point for the hydrogenation reaction, an antioxidant (BHT) was continuously added to the hydrogenated polymer solution at a rate of 0.055 g / min (n-hexane solution) such that the amount was 0.2 g per 100 g of polymer, thereby terminating the hydrogenation reaction. Subsequently, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer (Sample 20) in which a portion of the conjugated diene polymer was hydrogenated and the main chain had a tetrabranched structure derived from trimethoxy(4-vinylphenyl)silane (a compound represented by Formula (3) described above). Various physical properties of the sample were then measured. The measurement results are shown in Table 2.

[0432] (Comparative Synthesis Example 11) Modified conjugated diene polymer (Sample 21)

[0433] A modified conjugated diene polymer (Sample 21) was obtained in the same manner as Comparative Synthesis Example 10, except that the amount of hydrogen added during the hydrogenation reaction was changed from 1536 ml / min to 4470 ml / min (equivalent to a hydrogenation rate of 35 mol% for double bonds derived from butadiene in the conjugated diene polymer) from the manufacturing conditions of Comparative Synthesis Example 10, and various physical properties were measured. The measurement results are shown in Table 2.

[0434]

[0435]

[0436] (Examples 1, 2 and Comparative Example 10)

[0437] Samples 1 and 18 shown in Tables 1 and 2 were used as raw rubbers, and rubber compositions containing each raw rubber were obtained according to the formulations shown in Table 3.

[0438] (Carbon blending, mixing method Examples 1, 2 and Comparative Example 10)

[0439] Rubber compositions were obtained by kneading the materials shown in Table 3 by the following method. A closed mixer (capacity 0.3L) equipped with a temperature control device was used, and as a first stage of mixing, raw rubber (Samples 1 and 18), carbon black, (silica, silane coupling agent), SRAE oil, zinc oxide, and stearic acid were mixed under conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. At this time, the temperature of the closed mixer was controlled so that each rubber composition (compound) was obtained at a discharge temperature of 155 to 160℃.

[0440] Next, as a second stage of mixing, the compound obtained above was cooled to room temperature, an anti-aging agent was added, and the mixture was mixed again to improve the dispersion of carbon black. In this case as well, the discharge temperature of the compound was adjusted to 155 to 160°C by controlling the temperature of the mixer. After cooling, as a third stage of mixing, sulfur and vulcanization accelerator 1 were added and mixed using an open roll set to 70°C. Subsequently, the mixture was molded and vulcanized in a vulcanization press at 160°C for 30 minutes. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, they were evaluated by the following method. The results are shown in Table 4.

[0441] (Comparative Examples 1 and 2)

[0442] Sample 1 shown in Table 1 was used as the raw rubber, and a rubber composition containing the raw rubber was obtained according to the formulation shown in Table 3.

[0443] (Comparative Examples 1 and 2 of Silica Blending and Mixing Methods)

[0444] A rubber composition was obtained by kneading the materials shown in Table 3 by the following method. A closed mixer (capacity 0.3L) equipped with a temperature control device was used, and as a first stage of kneading, raw rubber (Sample 1), (carbon black), silica, silane coupling agent, SRAE oil, zinc oxide, and stearic acid were kneaded under conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. At this time, the temperature of the closed mixer was controlled so that the discharge temperature was 155 to 160°C to obtain the rubber composition (compound).

[0445] Next, as a second stage of mixing, the mixture obtained above was cooled to room temperature, an anti-aging agent was added, and the mixture was mixed again to improve the dispersion of silica. In this case as well, the discharge temperature of the mixture was adjusted to 155 to 160°C by controlling the temperature of the mixer. After cooling, as a third stage of mixing, sulfur and vulcanization accelerators 2 and 3 were added and mixed using an open roll set to 70°C. Subsequently, the mixture was molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, they were evaluated by the following method. The results are shown in Table 4.

[0446] (Evaluation 1) Coldflow properties

[0447] Samples 1 and 18 were cut from the bale to a sample size of L×W×H = 40 mm × 40 mm × 50 mm, a load of 1 kg was applied, and the samples were left to stand for 24 hours under an environment of 40°C. After 24 hours, the height (H) of the samples was measured, and the average retention rate of the two test points was calculated and indexed using the result of Comparative Example 10 as 100. A higher index indicates better cold flow performance. The results are shown in Table 4.

[0448] (Evaluation 2) Mixture Pattern Viscosity

[0449] The mixture obtained from the above-described second stage of mixing and prior to the third stage of mixing was used as a sample. Using a Mooney viscometer in accordance with ISO 289, the viscosity was measured after preheating at 130°C for 1 minute and rotating the rotor at 2 revolutions per minute for 4 minutes. The result of Comparative Example 10 was indexed with 100. A lower index indicates better processability. The results are shown in Table 4.

[0450] (Evaluation 3) Sheet Status

[0451] The mixture obtained from the above-described second stage of mixing and prior to the third stage of mixing was used as a sample, and the edge and surface condition of the rubber composition sheet, which was passed three times using a 10-inch open roll temperature-controlled to 70°C under conditions of a guide width of 200 mm and a clearance of 2.5 mm, was visually judged as follows. The results are shown in Table 4.

[0452] ◎: Edges and surface are smooth,

[0453] ○: The edges are slightly rough, but the surface is smooth,

[0454] △: High edge roughness and visible surface roughness,

[0455] ×: The edge and surface are severely rough, making sheet forming difficult.

[0456] (Evaluation 4) Tensile Strength

[0457] Tensile strength was measured in accordance with the tensile test method of JIS K6251, and the result of Comparative Example 10 was indexed to 100. A higher index indicates better tensile strength. The results are shown in Table 4.

[0458] (Rating 5) Pain Effect

[0459] Storage modulus (G') measured at a strain of 0.1% in torsion mode at a temperature of 50°C and a frequency of 10 Hz using the Rheometrics Scientific "ARES" viscoelasticity tester. 0.1 ) and storage modulus (G') measured at 10% strain 10 The difference ΔG'(G') from ) 0.1 -G' 10 The Paine effect was calculated and indexed with the result of Comparative Example 10 set to 100. A lower index indicates better dispersion of the filler. The results are shown in Table 4.

[0460] (Rating 6) Fuel Economy

[0461] Using the "ARES" viscoelasticity tester manufactured by Rheometrics Scientific, tanδ measured in torsion mode at a temperature of 50°C, a frequency of 10 Hz, and a deformation of 3% was used as an indicator of fuel efficiency, and the result of Comparative Example 10 was indexed with 100. A lower index indicates better fuel efficiency. The results are shown in Table 4.

[0462] (Evaluation 7) Wear resistance

[0463] Using an Akron wear tester (manufactured by Yasuda Seki Seisakusho Co., Ltd.), the amount of wear was measured at a load of 44.4 N and 1,000 rotations in accordance with JIS K6264-2, and the result of Comparative Example 10 was indexed to 100. A lower index indicates better wear resistance. The results are shown in Table 4.

[0464] (Evaluation 8) Same magnification

[0465] Using MTS ACUMEN3 in accordance with JIS K6385, the static spring constant and dynamic spring constant of the crosslinked rubber composition were measured, and the dynamic magnification ratio (dynamic spring constant / static spring constant) was calculated and indexed with the result of Comparative Example 10 set to 100. A smaller index indicates superior vibration damping properties. The results are shown in Table 4.

[0466]

[0467] Carbon Black: Tokai Carbon "Syst KH (N550)"

[0468] Silica: Evonik Degussa "Ultrasil 7000GR"

[0469] Nitrogen adsorption specific surface area 170 m² / g

[0470] Silica silane coupling agent: Evonik Degussa "Si75"

[0471] Bis(triethoxysilylpropyl)disulfide

[0472] SRAE Oil: JX Nikko Nisseki Energy "NC140"

[0473] Anti-aging agent: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine

[0474] Vulcanization Accelerator 1: N-(tert-butyl)-2-benzothiazolesulfenamide

[0475] Vulcanization Accelerator 2: N-cyclohexyl-2-benzothiazylsulfinamide

[0476] Vulcanization Accelerator 3: Diphenylguanidine

[0477]

[0478] As shown in Table 4, compared to Comparative Examples 1 and 2 of the silica formulation, the carbon black formulations were found to have lower viscosity and excellent processability, in addition to good dispersion of fillers, and excellent tensile strength, fuel efficiency, wear resistance, and dynamic magnification.

[0479] (Examples 3 to 11, Comparative Examples 3 to 13)

[0480] A rubber composition containing each raw rubber was obtained according to the compounding conditions and mixing method of Example 1, except that samples 2 to 21 shown in Tables 1 and 2 were used as raw rubbers, and the conjugated diene polymer sample 1 shown in Example 1 of Table 3 above was changed to samples 2 to 21 respectively.

[0481] The results of the physical property evaluations are shown in Tables 5 and 6 according to the aforementioned (Evaluation 1) to (Evaluation 8). Additionally, the evaluations of Example 1 and Comparative Example 10 are also shown.

[0482]

[0483]

[0484] As shown in Tables 5 and 6, Examples 1 and 3 to 11 were confirmed to have excellent cold flow resistance compared to Comparative Examples 3 to 13, good processability with low Mooney viscosity when vulcanized, low paint effect when vulcanized, and excellent fuel efficiency, tensile strength, and dynamic magnification.

Claims

Claim 1 A rubber composition comprising 10 to 150 parts by mass of carbon black per 100 parts by mass of a rubber component comprising at least one conjugated diene polymer, wherein the content of a silica-based inorganic filler is 0 to 30 parts by mass relative to the total amount of filler, and wherein 10 to 10 parts by mass of the rubber component is a modified conjugated diene polymer, wherein the modified conjugated diene polymer comprises: (1) a main chain branched structure having a branched structure in the main chain; (2) the main chain branched structure comprises a structure derived from at least one conjugated diene monomer, or a structure derived from at least one conjugated diene monomer and a structure derived from an aromatic vinyl monomer; (3) a terminal group having at least one carbonyl group and at least one substituted amino group in the molecule at at least one end; and (4) a Mooney viscosity measured at 100°C of 30 to A rubber composition having a molecular weight distribution of 1.60 to 3.00, and a hydrogenation rate of less than 10 mol%, (5) a branching degree (Bn) of 1.1 or greater and less than 4.0 by GPC-light scattering method with a viscosity detector attached, (6) a chromatographic shape measured by a gel permeation chromatograph (GPC) that is monomodal, and a molecular weight distribution of less than 10 mol%. Claim 2 A rubber composition according to claim 1, wherein the amount of 1,2-vinyl bonds in the conjugated diene units of the modified conjugated diene polymer is 10 mol% or more and 25 mol% or less. Claim 3 A rubber composition according to claim 1, wherein the aromatic vinyl bond content of the modified conjugated diene polymer is 0 mass% or more and 10 mass% or less. Claim 4 A rubber composition according to claim 1, wherein the glass transition temperature (Tg) of the modified conjugated diene polymer is -110℃ to -80℃. Claim 5 A rubber composition according to claim 1, wherein the modification rate of the modified conjugated diene polymer measured by column adsorption GPC is 40 mass% or more. Claim 6 A rubber composition according to claim 1, wherein the hydrogenation rate of the modified conjugated diene polymer is less than 5 mol%. Claim 7 A rubber composition according to claim 1, wherein the modified conjugated diene polymer has a structure represented by the following formula (1) and / or the following formula (2). (In Formula (1), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and Ra and Rb each independently represent a hydrocarbon group having 1 to 20 carbon atoms.) (In Formula (2), P represents a conjugated diene polymer containing at least one conjugated diene monomer, and Ra and Rb each independently represent a hydrocarbon group having 1 to 20 carbon atoms.) Claim 8 A rubber composition according to claim 1, wherein the main chain branching structure of the modified conjugated diene polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosyl group, and the portion derived from the vinyl monomer containing the alkoxysilyl group or a halosyl group has the branching structure. Claim 9 A rubber composition according to claim 7, wherein the portion derived from the vinyl monomer containing the alkoxysilyl group or halosyl group is a monomer unit derived from a compound represented by the following formula (3) or the following formula (4), and the branch structure in the main chain branch structure of the modified conjugated diene polymer has a branch point of the polymer chain formed by a monomer unit derived from the compound represented by the following formula (3) or the following formula (4). (during food, R 1 Representing an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms that may have a branched structure on silver, a hydrogen atom, or a part thereof, and R 2 to R 3 R represents, respectively, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms that may have a branched structure in a part thereof, and in the case where multiple are present. 1 to R 3 Each is independent. 1 ..., representing an independent halogen atom, m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, and (m+n+l) is 3.) (during food, R 2 to R 5 Each represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a part thereof, and R in the case where multiple groups exist. 2 to R 5 are, each independent, and X 2 To X 3 Each represents an independent halogen atom, m represents an integer from 0 to 2, n represents an integer from 0 to 3, l represents an integer from 0 to 3, (m+n+l) is 3, a represents an integer from 0 to 2, b represents an integer from 0 to 3, c represents an integer from 0 to 3, and (a+b+c) is 3. Claim 10 In claim 9, the main chain branching structure of the modified conjugated diene polymer has monomer units derived from the compound represented by formula (3), and among formula (3), R 1 A rubber composition representing this hydrogen atom, where m represents 0. Claim 11 A rubber composition according to claim 9, wherein the main chain branching structure of the modified conjugated diene polymer has monomer units derived from a compound represented by formula (4), wherein in formula (4), m represents 0 and b represents 0. Claim 12 In claim 9, the main chain branching structure of the modified conjugated diene polymer has monomer units derived from the compound represented by formula (3), and among formula (3), R 1 A rubber composition representing this hydrogen atom, where m represents 0, n represents 3, and l represents 0. Claim 13 A rubber composition according to claim 9, wherein the main chain branching structure of the modified conjugated diene polymer has monomer units derived from a compound represented by formula (4), wherein in formula (4), m represents 0, n represents 3, l represents 0, a represents 0, b represents 0, and c represents 3. Claim 14 A vulcanized rubber composition obtained by vulcanizing the rubber composition described in any one of claims 1 to 13.

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