Rubber composition for tires and tires

Abstract

The present invention aims to provide a rubber composition for tires that exhibits excellent rolling performance, wet performance, abrasion resistance, and aging resistance, and a tire manufactured using the composition. The present invention is a rubber composition for tires that contains a diene rubber including a modified conjugated diene rubber, silica, a silane coupling agent, and an alkyltriethoxysilane, the modified conjugated diene rubber being a conjugated diene rubber that satisfies a specific formula and has a modifying group that contains a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, and the proportion of the modified conjugated diene rubber in the diene rubber is 25 mass% or more.

Description

[Technical field]

[0001] The present invention relates to a rubber composition for a tire and a tire. [Background technology]

[0002] 2. Description of the Related Art Conventionally, rubber compositions for tires containing silica from the viewpoint of improving performance have been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7196953 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, there has been a demand for tires to have further improved rolling performance from the viewpoint of environmental issues, etc. In addition, there has been a demand for further improvements in wet performance, wear resistance, aging resistance, etc. from the viewpoint of safety, etc. Under these circumstances, the present inventors have studied the conventional rubber compositions for tires described in Patent Document 1 and the like, and have found that it is desirable to further improve the rolling performance, wet performance, wear resistance, and aging resistance of the rubber compositions when used in tires.

[0005] In view of the above-mentioned circumstances, the present invention has an object to provide a rubber composition for tires which, when made into a tire, exhibits excellent rolling performance, wet performance, abrasion resistance and aging resistance, and a tire manufactured using the rubber composition for tires. [Means for solving the problem]

[0006] As a result of intensive research into the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by using a specific modified conjugated diene rubber as the rubber component and containing silica, a silane coupling agent and an alkyltriethoxysilane, and have arrived at the present invention. That is, the present inventors have found that the above problems can be solved by the following configuration.

[0007] [1] The composition contains a diene rubber including a modified conjugated diene rubber (A1), silica, a silane coupling agent, and an alkyltriethoxysilane, The modified conjugated diene rubber (A1) satisfies the following formula (1) and the following formula (2) and has a modifying group containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, A rubber composition for tires, wherein the proportion of the modified conjugated diene rubber (A1) in the diene rubber is 25% by mass or more. IVw 10% ≦3.1×10 -6 ×Mw 10% -2.77 (1) IVw 10% <4.7 (2) IVw in formula (1) and formula (2) 10% and Mw in formula (1) 10% The details are as follows: The modified conjugated diene rubber is subjected to gel permeation chromatography measurement using a differential refractive index detector and a viscosity detector. The weight average molecular weight calculated using the high molecular weight side portion of the peak obtained by the differential refractive index detector, which is 10% of the total peak area, is defined as Mw 10% The weight-average intrinsic viscosity determined by using the high molecular weight portion of the peak in the chromatogram obtained by the viscometer, which is 10% of the total peak area, is defined as IVw 10% However, the unit of weight average intrinsic viscosity is dL / g. [2] The modified conjugated diene rubber (A1) is It has a star structure with three or more branches, and at least one branch chain of the star structure has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group. The rubber composition for tires according to [1], having a further main chain branched structure in the above portion. [3] It further contains a modified conjugated diene rubber (A2) other than the above modified conjugated diene rubber (A1). The rubber composition for tires according to [1] or [2], wherein the total proportion of the above modified conjugated diene rubber (A1) and the above modified conjugated diene rubber (A2) in the above diene rubber is 70% by mass or more. [4] The above Mw 10% is 2.0×10 6 or more, and the rubber composition for tires according to any one of [1] to [3]. [5] The rubber composition for tires according to any one of [1] to [4], wherein the content of the above silica is 50 parts by mass or more with respect to 100 parts by mass of the above diene rubber. [6] The above silane coupling agent includes 3 - octanoylthio - 1 - propyltriethoxysilane or a sulfur - containing silane coupling agent represented by the following average composition formula (X), and the content of the above silane coupling agent is 2 to 20% by mass of the content of the above silica. The rubber composition for tires according to any one of [1] to [5]. (A) a (B) b (C) c (D) d (R 1 ) e SiO (4-2a-b-c-d-e) / 2 (X) In formula (X), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R 1 represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. a to e satisfy the relational expressions of 0≦a<1, 0<b<1, 0<c<3, 0<d<1, 0≦e<2, and 0<2a + b + c + d + e<4. [7] Further containing a thermoplastic resin, The rubber composition for tires according to any one of [1] to [6], wherein the thermoplastic resin comprises at least one selected from the group consisting of terpene resins, C5 / C9 resins, C9 resins, DCPD resins, DCPD / C9 resins, hydrogenated C5 / C9 resins, hydrogenated C9 resins, hydrogenated DCPD resins, and hydrogenated DCPD / C9 resins. [8] Further containing a thermoplastic resin, The rubber composition for tires according to any one of [1] to [7], wherein the thermoplastic resin comprises at least two resins selected from the group consisting of terpene resins, C5 / C9 resins, C9 resins, DCPD resins, DCPD / C9 resins, hydrogenated C5 / C9 resins, hydrogenated C9 resins, hydrogenated DCPD resins, and hydrogenated DCPD / C9 resins. [9] A tire manufactured using the rubber composition for a tire according to any one of [1] to [8]. Effect of the Invention

[0008] As described below, according to the present invention, it is possible to provide a rubber composition for tires which, when made into a tire, exhibits excellent rolling performance, wet performance, abrasion resistance and aging resistance, and a tire produced using the rubber composition for tires. [Brief description of the drawings]

[0009] [Figure 1] This is an example of a GPC chromatogram. [Diagram 2] 1 is a partial cross-sectional schematic view showing an example of an embodiment of a tire of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The rubber composition for tires and the like of the present invention will be described below. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In addition, each component may be used alone or in combination of two or more. When two or more components are used in combination, the content of the components refers to the total content unless otherwise specified. In addition, the method for producing each component is not particularly limited unless otherwise specified, and may be, for example, a conventionally known method. Furthermore, with regard to a rubber composition for tires, the rolling performance, wet performance, wear resistance and aging resistance when made into a tire are also simply referred to as "rolling performance", "wet performance", "wear resistance" and "aging resistance", respectively. In addition, in this specification, a power of 10 may be represented as E. For example, E+5 represents 10 to the fifth power. In the present invention, when the standard for the proportion of a component is "in the diene rubber", the diene rubber refers to the entire diene rubber including the specific conjugated diene rubber. When the standard for the content of a component is "based on 100 parts by mass of the diene rubber", 100 parts by mass of the diene rubber refers to 100 parts by mass of the total amount of the diene rubber including the specific conjugated diene rubber.

[0011] [I] Rubber composition for tires The rubber composition for tires of the present invention (hereinafter also referred to as "the composition of the present invention") has The composition contains a diene rubber including a modified conjugated diene rubber (A1), silica, a silane coupling agent, and an alkyltriethoxysilane, The modified conjugated diene rubber (A1) satisfies the formula (1) and the formula (2) described later, and has a modifying group containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, In the rubber composition for tires, the proportion of the modified conjugated diene rubber (A1) in the diene rubber is 25% by mass or more.

[0012] It is believed that the composition of the present invention, having such a structure, can solve the above-mentioned problems. Although the reason for this is not clear, it is believed to be roughly as follows. The composition of the present invention contains, as a rubber component, a conjugated diene rubber (hereinafter also referred to as a "specific conjugated diene rubber") that satisfies the formula (1) and the formula (2) described below and has a modified group (hereinafter also referred to as a "specific modified group") that contains a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto. It is considered that the specific modified group of the specific conjugated diene rubber interacts with silica. In addition, the formula (1) specifies the relationship between the weight average intrinsic viscosity on the high molecular weight side and the weight average molecular weight on the high molecular weight side, but the inventors' studies have found that the specific conjugated diene rubber has room for improvement in rolling performance and wet performance. The inventors, who thought that the above improvement required improvement of the dispersibility of silica in the rubber composition, applied alkyltriethoxysilane to the specific conjugated diene rubber. It is considered that this extremely increased the dispersibility of silica in the composition of the present invention, leading to improvement not only in rolling performance and wet performance, but also in wear resistance and aging resistance.

[0013] Each component contained in the composition of the present invention will be described below.

[0014] [1] Rubber component The composition of the present invention contains, as a rubber component, a diene rubber including a specific conjugated diene rubber. The composition of the present invention may further contain, as a rubber component, a diene rubber other than the specific conjugated diene rubber.

[0015] [Specific conjugated diene rubber] The specific conjugated diene rubber is a conjugated diene rubber that satisfies the formula (1) described below and the formula (2) described below and has a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto.

[0016] [Skeleton] The skeleton of the specific conjugated diene rubber is a polymer having repeating units derived from a conjugated diene.

[0017] <Conjugated diene> Specific examples of the conjugated diene include butadiene (particularly 1,3-butadiene), isoprene, chloroprene, etc. The conjugated diene is preferably butadiene (particularly 1,3-butadiene) or isoprene, and more preferably butadiene (particularly 1,3-butadiene), because the effects of the present invention are more excellent.

[0018] <Other monomers> The skeleton of the specific conjugated diene rubber may have a repeating unit other than the repeating unit derived from the conjugated diene. Examples of the monomer (other monomer) that becomes such a repeating unit include vinyl monomers, alkenes (e.g., ethylene, propylene, butene), etc. Examples of the vinyl monomer include aromatic vinyl (e.g., styrene), acrylonitrile, and the specific branching agent described later.

[0019] <Example> Specific examples of the skeleton of the specific conjugated diene rubber include natural rubber (NR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber, isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR), etc. Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene-butadiene rubber (SBR), styrene-isoprene copolymer rubber, etc. The skeleton of the specific conjugated diene rubber is preferably SBR, since this provides better effects of the present invention.

[0020] [Specific modifying group] As described above, the specific conjugated diene rubber has a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent to the silicon atom. The specific modifying group may be present at any one of the terminals, main chain, or side chain of the skeleton of the specific conjugated diene rubber. The specific modifying group preferably contains a silicon atom and an oxygen atom adjacent thereto as an alkoxysilyl group, because the effect of the present invention is more excellent. The alkoxysilyl group is represented by the formula -Si(OR1) n (R2) 3-n (wherein R1 is an alkyl group, R2 is a hydrogen atom or an alkyl group, and n is an integer of 1 to 3). The specific modifying group preferably contains a nitrogen atom as an amino group (primary to tertiary amino group) because this provides better effects of the present invention. The specific modifying group is preferably a group derived from a specific modifying agent described below, because the effects of the present invention are more excellent.

[0021] [Equation (1), Equation (2)] The specific conjugated diene rubber satisfies the following formulas (1) and (2). Formula (1) specifies the relationship between the weight-average intrinsic viscosity on the high molecular weight side and the weight-average molecular weight on the high molecular weight side, and polymers that have a small molecular size relative to their molecular weight, such as those that have branches, tend to satisfy formula (1). The reason for limiting the molecular weight side is that it has a large effect on the physical properties of the entire polymer.

[0022] IVw 10% ≦3.1×10 -6 ×Mw 10% -2.77 (1) IVw 10% <4.7 (2)

[0023] IVw in formula (1) and formula (2) 10% and Mw in formula (1) 10% is calculated as follows: The modified conjugated diene rubber is subjected to gel permeation chromatography measurement using a differential refractive index detector (RI detector) and a viscosity detector. The weight average molecular weight calculated using the high molecular weight side portion of the chromatogram peak obtained by the differential refractive index detector, which is 10% of the total peak area, is defined as Mw 10%The weight-average intrinsic viscosity determined by using the high molecular weight portion of the peak in the chromatogram obtained by the viscometer, which is 10% of the total peak area, is defined as IVw 10% However, the unit of weight average intrinsic viscosity is dL / g.

[0024] Hereinafter, IVw in formula (1) and formula (2) 10% and Mw in formula (1) 10% This will be explained in more detail.

[0025] As described above, the modified conjugated diene rubber is subjected to gel permeation chromatography (GPC) measurement using a differential refractive index detector and a viscosity detector as detectors. The specific method of GPC measurement is as follows.

[0026] Toluene containing 5 mmol / L triethylamine is used as the eluent. Three columns packed with polystyrene gel (product names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Tosoh Corporation) are connected together and used. The sample to be measured is dissolved in toluene to a concentration of 1 mg / mL to prepare a measurement solution, and 100 μL of the measurement solution is injected into the GPC measurement device and measured under conditions of an oven temperature of 40°C and a toluene flow rate of 1 mL / min.

[0027] The weight average molecular weight is calculated using the high molecular weight side (the side with a short elution time) which is 10% of the total area of ​​the peaks (peaks due to modified conjugated diene rubber) in the chromatogram (horizontal axis: elution time, vertical axis: signal intensity) obtained by the differential refractive index detector. The weight average molecular weight obtained is Mw 10% Let us assume that.

[0028] In addition, the weight-average intrinsic viscosity is calculated using the high molecular weight side (the side with the short elution time) which is 10% of the total area of ​​the peaks (peaks derived from modified conjugated diene rubber) in the chromatogram (horizontal axis: elution time, vertical axis: signal intensity) obtained by the viscosity detector. The weight-average intrinsic viscosity obtained is called IVw 10% Let us assume that. The weight average intrinsic viscosity is defined as (Σ(ηi×Mi×Ni)) / (Σ(Mi×Ni)), where Ni is the number of molecules and ηi is the intrinsic viscosity at molecular weight Mi.

[0029] An example of a GPC chromatogram (horizontal axis: elution time, vertical axis: signal intensity) is shown in Figure 1. The Mw 10% and IVw 10% Request.

[0030] As a method for making the modified conjugated diene rubber satisfy the formula (1), for example, a method of changing the type and amount of the specific modifier and the type and amount of the specific branching agent in the production method of the present invention described later can be mentioned.

[0031] 〔Mw 10% 〕 Mw 10% is preferably 100,000 to 10,000,000, and more preferably 2.0×10 6 It is more preferable that the molecular weight is (2,000,000) to 5,000,000. Mw 10% It is preferable that the molecular weight is 3,000,000 to 5,000,000 because the effects of the present invention (particularly, wear resistance) are more excellent. Mw 10% It is preferable that the molecular weight is more than 100,000 and less than 3,000,000 because the effects of the present invention (particularly, wet performance and aging resistance) are more excellent.

[0032] [IVw 10% 〕 IVw 10% is preferably 3.0 or more and less than 4.7 because the effects of the present invention are more excellent. IVw 10% is more preferably 3.0 or more and 4.0 or less, because the effects of the present invention (particularly, wear resistance) are more excellent. IVw 10%is more preferably greater than 4.0 and 4.5 or less, because the effects of the present invention (particularly, wet performance and aging resistance) are more excellent.

[0033] [Formula (3)] For the reason that the effects of the present invention (particularly, wet performance and aging resistance) are more excellent, it is preferable that the specific conjugated diene rubber further satisfies the following formula (3).

[0034] 30≦St+Vn≦90 (3)

[0035] In formula (3), St represents the ratio (mass%) of repeating units derived from styrene to the entire specific conjugated diene rubber (hereinafter also referred to as the "styrene amount"), and Vn represents the ratio (mass%) of repeating units of 1,2-vinyl structure derived from a conjugated diene (e.g., butadiene) to the entire specific conjugated diene rubber (hereinafter also referred to as the "vinyl amount").

[0036] It is preferable that St+Vn is more than 50 and 90 or less, because the effects of the present invention are more excellent.

[0037] St is preferably more than 10 and 50 or less, because the effects of the present invention are more excellent.

[0038] Vn is preferably more than 0 and 40 or less, because the effects of the present invention are more excellent.

[0039] [Molecular weight] The weight average molecular weight (Mw) of the specific conjugated diene rubber is preferably from 100,000 to 2,000,000, and more preferably from 200,000 to 1,300,000, because the effects of the present invention are more excellent. The weight average molecular weight (Mw) of the specific conjugated diene rubber is measured by the same method as described above except that the entire peak is used. 10% is the same as:

[0040] [Glass transition temperature] The glass transition temperature (Tg) of the specific conjugated diene rubber is not particularly limited, but is preferably from -100°C to 0°C, and more preferably from -80°C to -10°C, for reasons of better effect of the present invention. The glass transition temperature can be adjusted, for example, by the amount of styrene or vinyl. In this specification, the glass transition temperature (Tg) is measured using a differential scanning calorimeter (DSC) at a temperature rise rate of 10° C. / min and calculated by the midpoint method.

[0041] [Preferred embodiment 1] The specific conjugated diene rubber preferably has a star structure with three or more branches, more preferably has a star structure with three or more branches having a specific modifying group as a branch point, and further preferably is a conjugated diene rubber represented by the following formula (A), because the effects of the present invention are more excellent.

[0042] [ka]

[0043] In formula (A), X represents an n-valent group (specific modifying group) containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, P represents a conjugated diene polymer chain, and n represents an integer of 3 or more.

[0044] As described above, X represents an n-valent group (specific modifying group) containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto. X preferably contains a silicon atom and an oxygen atom adjacent thereto as an alkoxysilyl group, because this provides a better effect of the present invention. X preferably contains a nitrogen atom as an amino group because the effect of the present invention is more excellent.

[0045] As described above, P represents a conjugated diene polymer chain. A plurality of P's may be the same or different. The definition, specific examples and preferred embodiments of the conjugated diene polymer chain are the same as those of the skeleton of the specific conjugated diene rubber described above.

[0046] As described above, n represents an integer of 3 or more. There is no particular upper limit to n, but it is preferably 30 or less because the effects of the present invention are more excellent.

[0047] [Preferred embodiment 2] When the specific conjugated diene rubber has a star structure with three or more branches, at least one branched chain (conjugated diene polymer chain) of the star structure preferably has a portion derived from a specific branching agent described later, and further has a main chain branched structure, because the effects of the present invention are more excellent. The main chain branched structure refers to a structure in which a branched chain (conjugated diene polymer chain) forms a branch point at a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and a polymer chain (e.g., another conjugated diene polymer chain) extends from the branch point.

[0048] [Proportion of specific conjugated diene rubber] In the present invention, the proportion of the specific conjugated diene rubber in the diene rubber is 25% by mass or more. The above ratio is preferably 30% by mass or more, and more preferably 50% by mass or more and 90% by mass or less, because the effects of the present invention are superior.

[0049] [Other rubber components] The rubber component may further contain a rubber component (other rubber component) other than the specific conjugated diene rubber.

[0050] (Other diene rubbers) Examples of diene rubbers other than the specific conjugated diene rubber in the diene rubber (other diene rubbers) that the composition of the present invention may further contain include natural rubber (NR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber (e.g., styrene-butadiene rubber (SBR), styrene-isoprene copolymer rubber, etc.), isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR), etc. The other diene rubber may be modified. However, the modification in the modified other diene rubber [modified conjugated diene rubber (A2)] does not include a specific modifying group. The modified other diene rubber may have, for example, a hydroxyl group, an epoxy group, or a polysiloxane group. From the viewpoint of achieving superior effects of the present invention, the other diene rubber that the rubber component can further contain preferably contains natural rubber (NR), butadiene rubber (BR) or SBR, more preferably contains natural rubber (NR) and / or SBR, and further preferably contains unmodified NR and modified SBR. The proportion of the other diene rubber in the diene rubber can be the remainder obtained by subtracting the range of the proportion of the specific conjugated diene rubber from 100% by mass. The proportion of the modified other diene rubber [modified conjugated diene rubber (A2)] in the diene rubber can be 0 to 50 mass % in the diene rubber.

[0051] When the diene rubber further contains a modified other diene rubber [modified conjugated diene rubber (A2)] other than the specific conjugated diene rubber [modified conjugated diene rubber (A1)], the total proportion of the modified conjugated diene rubber (A1) and the modified conjugated diene rubber (A2) in the diene rubber is preferably 70 mass% or more, and more preferably 75 to 90 mass%, from the viewpoint of obtaining better effects of the present invention. When the diene rubber further contains an unmodified diene rubber as a diene rubber other than the specific conjugated diene rubber [modified conjugated diene rubber (A1)], the proportion of the unmodified diene rubber in the diene rubber is preferably 0 to 30 mass %, more preferably 10 to 25 mass %, from the viewpoint of achieving better effects of the present invention.

[0052] In this specification, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the rubber components other than the specific conjugated diene rubber may be standard polystyrene equivalent values ​​obtained by gel permeation chromatography (GPC) measurement under the following conditions. Solvent: Tetrahydrofuran Detector: RI detector

[0053] [Method of manufacturing specific conjugated diene rubber] The method for producing the specific conjugated diene rubber is not particularly limited, but a method including the following steps (1) and (2) (hereinafter also referred to as the "production method of the present invention") is preferred because it provides better effects of the present invention. (1) A polymerization step in which a monomer containing a conjugated diene is polymerized by anionic polymerization to obtain a conjugated diene-based polymer. (2) A modification step in which the conjugated diene polymer obtained in the polymerization step is reacted with a compound containing a nitrogen atom and an alkoxysilyl group (hereinafter also referred to as a "specific modifier") to obtain a conjugated diene rubber having a specific modifying group.

[0054] [Polymerization process] The polymerization step is a step of obtaining a conjugated diene-based polymer by polymerizing a monomer containing a conjugated diene by anionic polymerization.

[0055] <Anionic Polymerization> The anionic polymerization is not particularly limited, but anionic polymerization using an organolithium compound as an initiator is preferred because the effects of the present invention are more excellent.

[0056] The organolithium compound is not particularly limited, and specific examples thereof include mono-organolithium compounds such as n-butyl lithium (n-BuLi), sec-butyl lithium, tert-butyl lithium, n-propyl lithium, iso-propyl lithium, and benzyl lithium; and polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,5-dilithiopentane, 1,6-dilithiohexane, 1,10-dilithiodecane, 1,1-dilithiodiphenylene, dilithiopolybutadiene, dilithiopolyisoprene, 1,4-dilithiobenzene, 1,2-dilithio-1,2-diphenylethane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, and 1,3,5-trilithio-2,4,6-triethylbenzene. Among these, the mono-organolithium compounds of n-butyl lithium, sec-butyl lithium, and tert-butyl lithium are preferred, and n-butyl lithium is more preferred, because the effects of the present invention are more excellent.

[0057] The amount of the organolithium compound used is not particularly limited, but is preferably 0.001 to 10 mol % based on the monomer, because this provides better effects of the present invention.

[0058] <Monomer> Specific examples and preferred embodiments of the conjugated diene-containing monomer used in the polymerization step are the same as those of the conjugated diene and other monomers in the skeleton of the specific conjugated diene-based rubber described above.

[0059] (Specific branching agent) The monomer preferably contains a vinyl monomer containing an alkoxysilyl group or a halosilyl group (hereinafter also referred to as a "specific branching agent") because this provides a superior effect of the present invention. The specific branching agent is preferably an aromatic vinyl (particularly styrene) containing an alkoxysilyl group or a halosilyl group, more preferably an aromatic vinyl containing an alkoxysilyl group, and even more preferably an aromatic vinyl containing a trialkoxysilyl group, for reasons that the effects of the present invention are more excellent.

[0060] (1) Specific examples Specific examples of aromatic vinyls containing an alkoxysilyl group include 1-(trimethoxysilyl)-4-vinylbenzene and 1,1-bis(4-trimethoxysilylphenyl)ethylene. Examples of aromatic vinyls containing a halosilyl group include trichloro(4-vinylphenyl)silane and 1,1-bis(4-trichlorosilylphenyl)ethylene.

[0061] (2) Usage amount The amount of the specific branching agent used is preferably 0.001 to 0.1% by mass, and more preferably 0.005 to 0.05% by mass, based on the conjugated diene, because this provides better effects for the present invention.

[0062] <Polar compounds> In the polymerization step, a polar compound may be added. This allows the monomers to be randomly copolymerized. In addition, polar compounds tend to be usable as vinylating agents for controlling the microstructure of conjugated dienes. In addition, polar compounds tend to be effective in promoting polymerization reactions.

[0063] Examples of polar compounds that can be used include ethers such as tetrahydrofuran, diethyl ether, dioxane, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate and sodium tert-butylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

[0064] (Amount used) The amount of the polar compound used is preferably 0.01 mol or more and 100 mol or less per mol of the initiator, because the effect of the present invention is more excellent.

[0065] [Modification step] The modification process is a process in which the conjugated diene polymer obtained in the polymerization process is reacted with a modifier (specific modifier) ​​containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, to obtain a conjugated diene rubber having a specific modifying group.

[0066] In the modification step, it is considered that the active terminal of the conjugated diene polymer obtained in the polymerization step is bonded to the silicon atom of the specific modifier. For example, when the specific modifier contains an alkoxysilyl group, it is considered that the active terminal is bonded to the silicon atom of the alkoxysilyl group, and the alkoxy group is eliminated. In addition, when the conjugated diene polymer obtained in the polymerization step has a portion derived from a specific branching agent, in addition to the above-mentioned active terminal, the alkoxysilyl group or halosilyl group of the above-mentioned portion is also considered to react with the specific modifying agent (e.g., alkoxysilyl group). In addition, the alkoxysilyl group or halosilyl group of the above-mentioned portion is also considered to react with the active terminal of another conjugated diene polymer. As a result, the conjugated diene polymer having a portion derived from a specific branching agent has a main chain branched structure (another conjugated diene polymer chain) in the above-mentioned portion.

[0067] <Specific modifier> The specific modifier is a compound containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto. For the reason that the effect of the present invention is more excellent, the specific modifier preferably contains a silicon atom and an oxygen atom adjacent thereto as an alkoxysilyl group (particularly, a trialkoxysilyl group) or a group containing a silazane structure (particularly, a cyclic silazane structure) in which an alkoxy group is bonded to the silicon atom of the silazane structure. Here, the silazane structure refers to a structure in which a silicon atom and a nitrogen atom are directly bonded (a structure having a Si-N bond). The specific modifying agent preferably contains a nitrogen atom as a group containing an amino group (primary to tertiary amino group) or a silazane structure (particularly a cyclic silazane structure) because this provides a better effect of the present invention. The specific modifying agent preferably has two or more (preferably three or more) sites capable of reacting with an active terminal such as an alkoxysilyl group. When the specific modifying agent has a plurality of such sites, the specific modifying agent functions as a coupling agent that connects conjugated diene polymers together.

[0068] (Specific examples) Specific examples of the specific modifier include tertiary amines having an alkoxysilyl group, such as tris(3-trimethoxysilylpropyl)amine and tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine; cyclic silazanes having an alkoxysilyl group, such as 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane; tertiary amines having a group containing an alkoxysilyl group-containing cyclic silazane structure, such as tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine and tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine; bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine; bis[3 -(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, and bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine are examples of tertiary amines having an alkoxysilyl group and a group containing a cyclic silazane structure.

[0069] (Amount used) The amount of the specific modifying agent used is preferably 0.01 to 1% by mass, and more preferably 0.02 to 0.2% by mass, based on the conjugated diene, because this provides a better effect of the present invention.

[0070] [Other steps] The production method of the present invention may include steps (other steps) other than the steps described above. Other steps include a polymerization terminating step in which a polymerization terminator (eg, methanol) is added, and a solvent removal step in which the solvent is removed by steam stripping.

[0071] [Molecular weight] The preferred embodiment of the weight average molecular weight (Mw) of the rubber component is the same as that of the specific conjugated diene rubber described above.

[0072] [2] Silica The compositions of the present invention contain silica. The silica is not particularly limited, and any conventionally known silica can be used. Examples of silica include wet silica, dry silica, fumed silica, and diatomaceous earth. Silica derived from biomass such as rice husk may also be used. The above silica may be used alone or in combination of two or more types.

[0073] [CTAB] The cetyltrimethylammonium bromide (CTAB) adsorption specific surface area of ​​silica (hereinafter, "CTAB adsorption specific surface area" may be simply referred to as "CTAB") is not particularly limited. However, in order to obtain a superior effect of the present invention, it is preferable to use a surface area of ​​100 to 300 m. 2 / g, and 150 to 200m 2 It is more preferable that the molecular weight is / g. Here, the CTAB adsorption specific surface area is a value measured in accordance with JIS K6430:2008, Annex G.

[0074] [Content] The content of silica is preferably 50 parts by mass or more, and more preferably 70 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of the diene rubber, because the effects of the present invention are more excellent.

[0075] [3] Silane coupling agents The composition of the present invention contains a silane coupling agent.

[0076] The silane coupling agent is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group. The hydrolyzable group is not particularly limited, and examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, and an alkenyloxy group. Among them, an alkoxy group is preferable because the effects of the present invention are more excellent. When the hydrolyzable group is an alkoxy group, the number of carbon atoms of the alkoxy group is preferably 1 to 16, and more preferably 1 to 4, because the effects of the present invention are more excellent. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, and a propoxy group.

[0077] The organic functional group is not particularly limited, but is preferably a group capable of forming a chemical bond with an organic compound, and examples thereof include an epoxy group, a vinyl group, an acryloyl group, a methacryloyl group, an amino group, a sulfide group, a mercapto group, a blocked mercapto group (protected mercapto group) (for example, a thioester group such as an octanoylthio group), and among these, a sulfide group (particularly a disulfide group or a tetrasulfide group), a mercapto group, and a blocked mercapto group are preferred because they provide better effects of the present invention. The silane coupling agents may be used alone or in combination of two or more kinds.

[0078] The silane coupling agent preferably contains a sulfur-containing silane coupling agent, because the effects of the present invention are more excellent.

[0079] Examples of the silane coupling agent include sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl)tetrasulfide (Si69), bis(3-trimethoxysilylpropyl)tetrasulfide, and bis(3-triethoxysilylpropyl)disulfide; mercapto-based silane coupling agents such as mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane; Thioester-based silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane (NXT); Examples of the silane coupling agent include a sulfur-containing polysiloxane-based silane coupling agent represented by the average composition formula (X) described below.

[0080] The silane coupling agent preferably contains a thioester-based silane coupling agent or a sulfur-containing polysiloxane-based silane coupling agent, because the effects of the present invention are more excellent. It is more preferable that the composition contains 3-octanoylthio-1-propyltriethoxysilane or a sulfur-containing silane coupling agent represented by the following average composition formula (X): It is more preferable that the silane compound contains 3-octanoylthio-1-propyltriethoxysilane. In this specification, the average composition formula (X) may be referred to as "formula (X)". The sulfur-containing silane coupling agent represented by the average composition formula (X) may be referred to as "the silane coupling agent represented by the formula (X)".

[0081] [Sulfur-containing silane coupling agent represented by average composition formula (X)] The silane coupling agent represented by formula (X) preferably has a polysiloxane skeleton, which may be linear, branched, or three-dimensional, or a combination of these. Formula (X) is as follows: (A) a (B) b (C) c (D) d (R 1 )e SiO (4-2a-b-c-d-e) / 2 (X) In formula (X), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R 1 represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. a to e satisfy the relational expressions of 0 ≦ a < 1, 0 < b < 1, 0 < c < 3, 0 < d < 1, 0 ≦ e < 2, and 0 < 2a + b + c + d + e < 4.

[0082] [A] A represents a divalent organic group containing a sulfide group. A may have a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom. A is preferably a group represented by the following formula (A1). *-(CH2)n-Sx-(CH2)n-* (A1) In formula (A1), n represents an integer of 1 to 10, x represents an integer of 1 to 6, and * indicates a bonding position. Specific examples of A represented by formula (A1) include, for example, *-CH2-S2-CH2-*, *-C2H4-S2-C2H4-*, *-C3H6-S2-C3H6-*, *-C4H8-S2-C4H8-*, *-CH2-S4-CH2-*, *-C2H4-S4-C2H4-*, *-C3H6-S4-C3H6-*, *-C4H8-S4-C4H8-*, and the like.

[0083] [B] B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. B is preferably a monovalent hydrocarbon group having 6 to 10 carbon atoms, more preferably 8 to 10 carbon atoms. Examples include a hexyl group, an octyl group, a decyl group, and the like.

[0084] [C] C represents a hydrolyzable group. Examples of C include an alkoxy group, a phenoxy group, a carboxyl group, an alkenyloxy group, and the like. C is preferably a group represented by the following formula (C1). *-OR 2 (C1) In formula (C1), * indicates the bonding position. Also, R 2 represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group (arylalkyl group) having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms. Among them, an alkyl group having 1 to 5 carbon atoms is preferable. Specific examples of the alkyl group having 1 to 5 carbon atoms include, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and the like.

[0085] [D] D represents an organic group containing a mercapto group. D is preferably a group represented by the following formula (D1). *-(CH2) m -SH (D1) In formula (D1), m represents an integer of 1 to 10, and among them, an integer of 1 to 5 is preferable. Also in the formula, * indicates the bonding position. Examples of the group represented by formula (D1) include, for example, *-CH2SH, *-C2H4SH, *-C3H6SH, *-C4H8SH, *-C5H 10 SH, *-C6H 12 SH, *-C7H 14 SH, *-C8H 16 SH, *-C9H 18 SH, *-C 10 H 20 SH.

[0086] [R 1 R 1 represents a monovalent hydrocarbon group having 1 to 4 carbon atoms. Examples of R 1 include, for example, a methyl group, an ethyl group, a propyl group, and a butyl group.

[0087] [a~e] a to e satisfy the relational expressions of 0≦a<1, 0<b<1, 0<c<3, 0<d<1, 0≦e<2, and 0<2a + b + c + d + e<4. a is preferably greater than 0, and more preferably 0<a≦0.50. b is preferably 0.10≦b≦0.89. ​Preferably, c satisfies 1.2≦c≦2.0. d is preferably in the range of 0.1≦d≦0.8.

[0088] [Content] The content of the silane coupling agent in the composition of the present invention is not particularly limited, but the content of the silane coupling agent is preferably 2 to 20 mass % of the above-mentioned silica content, and more preferably 5 to 15 mass %, because this provides better effects of the present invention.

[0089] [4] Alkyltriethoxysilane The composition of the present invention contains an alkyltriethoxysilane. It is believed that by including alkyltriethoxysilane in the composition of the present invention, the dispersibility of silica in the composition of the present invention is improved, resulting in excellent rolling performance, wet performance, wear resistance and aging resistance.

[0090] An example of the alkyltriethoxysilane is a compound represented by the following formula (Y). R 1 -Si-(OCH2CH3)3(Y) In formula (Y), R 1 represents an alkyl group having 7 to 20 carbon atoms. Examples of the alkyl group having 7 to 20 carbon atoms include a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. Of these, an octyl group and a nonyl group are preferred because they provide better effects of the present invention.

[0091] [Content] In the composition of the present invention, the content of alkyltriethoxysilane is not particularly limited, but in order to obtain better effects of the present invention, it is preferably 1.0 to 15.0 mass% of the above-mentioned silica content, and more preferably 2.0 to 10.0 mass%. Furthermore, the content of alkyltriethoxysilane is preferably 0.1 to 10 parts by mass, more preferably 1.0 to 5.0 parts by mass, and even more preferably 1.5 to 2.5 parts by mass, relative to 100 parts by mass of the diene rubber, because the effects of the present invention are more excellent.

[0092] [4] Optional component The composition of the present invention may contain components (optional components) other than the above-mentioned components, as necessary. Examples of such components include various additives that are generally used in rubber compositions, such as fillers other than silica (preferably carbon black), oils such as process oil, thermoplastic resins, zinc oxide (zinc white), stearic acid, antioxidants, waxes, processing aids, liquid polymers, thermosetting resins, vulcanizing agents (e.g., sulfur), vulcanization accelerators (accelerators), and vulcanization activators.

[0093] [Thermoplastic resin] The composition of the present invention preferably further contains a thermoplastic resin because the effects of the present invention are more excellent.

[0094] [Specific examples] Examples of the thermoplastic resin include coumarone resins (e.g., coumarone resin, coumarone-indene resin, coumarone-indene-styrene resin), phenol resins (e.g., phenol resin, phenol-acetylene resin, phenol-formaldehyde resin), xylene resins (e.g., xylene resin, xylene-acetylene resin, xylene-formaldehyde resin), rosin resins (e.g., rosin, rosin ester, hydrogenated rosin derivative), terpene resins (e.g., terpene resin, modified rosin), and the like. Examples of suitable resins include aromatic terpene resins (such as aromatic modified terpene resins), terpene phenol resins, hydrogenated terpene resins, α-pinene resins, β-pinene resins, limonene resins, hydrogenated limonene resins, dipentene resins, and terpene styrene resins), styrene-based resins, petroleum-based resins (for example, C5 / C9-based resins, C9-based resins, DCPD (dicyclopentadiene)-based resins, DCPD / C9-based resins, hydrogenated C5 / C9-based resins, hydrogenated C9-based resins, hydrogenated DCPD-based resins, and hydrogenated DCPD / C9-based resins), and aliphatic saturated hydrocarbon-based resins.

[0095] Because the effects of the present invention are more excellent, the thermoplastic resin preferably contains at least one selected from the group consisting of terpene resin, C5 / C9 resin, C9 resin, DCPD resin, DCPD / C9 resin, hydrogenated C5 / C9 resin, hydrogenated C9 resin, hydrogenated DCPD resin, and hydrogenated DCPD / C9 resin, and more preferably contains a terpene resin or a C5 / C9 resin. In addition, at least two types selected from the above group may be included. When at least two types selected from the above group are included, the combination is preferably a combination of a terpene resin and a C5 / C9 resin because the effect of the present invention is more excellent. The terpene resin is not particularly limited. For example, a conventionally known terpene resin can be mentioned. The same applies to the C5 / C9 resin.

[0096] [Content] In the composition of the present invention, the content of the thermoplastic resin (the total content when two or more kinds of thermoplastic resins are used) is not particularly limited, but in order to improve the effects of the present invention, it is preferably 0 to 30 parts by mass, more preferably 1 to 30 parts by mass, per 100 parts by mass of the diene rubber described above.

[0097] [Carbon black] The composition of the present invention preferably further contains carbon black because the effects of the present invention are more excellent. The carbon black may be used alone or in combination of two or more kinds. The carbon black is not particularly limited, and various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, and SRF can be used.

[0098] [N2SA] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, but is preferably 50 to 200 m because the effect of the present invention is more excellent. 2 / g, and 70 to 150m 2 It is more preferable that the molecular weight is / g. Here, the nitrogen adsorption specific surface area (N2SA) is the amount of nitrogen adsorbed on the surface of carbon black measured according to JIS K6217-2:2001 "Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method."

[0099] [Content] In the composition of the present invention, the content of carbon black is not particularly limited, but because the effects of the present invention are more excellent, the content is preferably 1 to 100 parts by mass, and more preferably 2 to 30 parts by mass, per 100 parts by mass of the above-mentioned diene-based rubber.

[0100] [5] Method for preparing rubber composition for tires The method for producing the composition of the present invention is not particularly limited, and specific examples thereof include a method of kneading the above-mentioned components using a known method or device (e.g., a Banbury mixer, a kneader, a roll, etc.) When the composition of the present invention contains sulfur or a vulcanization accelerator, it is preferable to first mix the components other than the sulfur and the vulcanization accelerator at a high temperature (preferably 100 to 160°C), cool the mixture, and then mix the sulfur or the vulcanization accelerator. The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[0101] [II] Tires The tire of the present invention is a tire manufactured using the above-mentioned composition of the present invention. The tire of the present invention is preferably a pneumatic tire, and can be filled with air, an inert gas such as nitrogen, or other gases.

[0102] 2 is a schematic partial cross-sectional view of a tire showing one example of an embodiment of the tire of the present invention. However, the tire of the present invention is not limited to the embodiment shown in FIG.

[0103] In FIG. 2, reference numeral 1 denotes a bead portion, reference numeral 2 denotes a sidewall portion, and reference numeral 3 denotes a tire tread portion. Between the pair of left and right bead portions 1, a carcass layer 4 having fiber cords embedded therein is installed, and the ends of this carcass layer 4 are folded back and wrapped around the bead cores 5 and bead fillers 6 from the inside to the outside of the tire. In the tire tread portion 3, a belt layer 7 is disposed on the outer side of the carcass layer 4 over one circumference of the tire. In addition, a rim cushion 8 is disposed in the bead portion 1 at a portion that comes into contact with the rim. At least one of the reference numerals 2 to 3, 5 to 6, and 8 (preferably reference numeral 3) is formed from the above-mentioned composition of the present invention.

[0104] The tire of the present invention can be manufactured, for example, according to a conventionally known method. The gas to be filled in the tire can be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium. EXAMPLES

[0105] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0106] [Synthesis of conjugated diene rubber] Each conjugated diene rubber was synthesized as follows.

[0107] [Conjugated diene rubber 3 (comparison)]

[0108] <Polymerization process> In a stirred autoclave, cyclohexane 1000g / h (hour), tetramethylethylenediamine 0.059g / h, 1,3-butadiene 153.0g / h, 1-butene 0.352g / h, and styrene 47.0g / h were charged under a nitrogen atmosphere, and n-butyllithium was continuously added at 1.43mmol / h to initiate polymerization at 70°C. When the polymerization was sufficiently stabilized, 1-(trimethoxysilyl)-4-vinylbenzene (branching agent) was added at 0.06g / h and the mixture was stirred to react. The branching agent corresponds to the specific branching agent described above.

[0109] <Denaturation process> To the solution flowing out from the reactor outlet, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (modifier) ​​was added at 0.28 g / h, and the mixture was stirred to react.

[0110] Thereafter, methanol was added as a polymerization terminator to obtain a solution containing a conjugated diene rubber.

[0111] To the resulting solution, 1.14 parts by mass of Irganox 1520L (manufactured by BASF) was added as an anti-aging agent per 100 parts by mass of the conjugated diene rubber, and the solvent was removed by steam stripping. The resulting mixture was vacuum dried at 60° C. for 24 hours to obtain a solid conjugated diene rubber. The resulting conjugated diene rubber is also referred to as conjugated diene rubber 3.

[0112] The conjugated diene rubber 3 is a reaction product between a conjugated diene polymer, which is a copolymer of butadiene, styrene and a branching agent, and a modifier, and is a modified conjugated diene rubber having a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, which is derived from the modifier. The conjugated diene rubber 3 has a star structure with three or more branches, with the modifying group as a branching point, and the branched chain bonded to the modifying group has a portion derived from a branching agent, and the portion derived from the branching agent has a further main chain branched structure (conjugated diene polymer chain).

[0113] [Conjugated diene rubber 5] A solid conjugated diene rubber was obtained in the same manner as for conjugated diene rubber 3, except that the amount of each component was changed as shown in Table 1. The obtained conjugated diene rubber is also referred to as conjugated diene rubber 5.

[0114] The conjugated diene rubber 5 is a reaction product between a conjugated diene polymer, which is a copolymer of butadiene, styrene and a branching agent, and a modifier, and is a modified conjugated diene rubber having a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, which is derived from the modifier. The conjugated diene rubber 5 has a star structure with three or more branches, with the modifying group as a branching point, and the branched chain bonded to the modifying group has a portion derived from a branching agent, and the portion derived from the branching agent has a further main chain branched structure (conjugated diene polymer chain).

[0115] [Conjugated diene rubber 6] A solid conjugated diene rubber was obtained in the same manner as in the case of the conjugated diene rubber 3, except that the amount of each component was changed as shown in Table 1. The obtained conjugated diene rubber is also referred to as conjugated diene rubber 6.

[0116] The conjugated diene rubber 6 is a reaction product between a conjugated diene polymer, which is a copolymer of butadiene, styrene and a branching agent, and a modifier, and is a modified conjugated diene rubber having a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, which is derived from the modifier. The conjugated diene rubber 2 has a star structure with three or more branches, with the modifying group as a branching point, and the branched chain bonded to the modifying group has a portion derived from a branching agent, and the portion derived from the branching agent has a further main chain branched structure (conjugated diene polymer chain).

[0117] [Table 1]

[0118] [Conjugated diene rubber 4 (comparison)] Into a nitrogen-purged autoclave reactor having an internal volume of 5 liters, 2,000 g of cyclohexane, 31.6 g of tetrahydrofuran, 122 g of styrene, and 320 g of 1,3-butadiene were charged. After adjusting the temperature of the contents of the reactor to 10°C, 4.75 mmol of n-butyllithium was added as a polymerization initiator to start polymerization. The polymerization was carried out under adiabatic conditions, and the maximum temperature reached 85°C. When the polymerization conversion rate reached 99% (20 minutes after the start of polymerization), 10 g of 1,3-butadiene was added over 2 minutes, and then 2.12 mmol of a compound (modifier) ​​of the following formula (4) was added and the reaction was carried out for 15 minutes. The modifier corresponds to the specific modifier described above. To the obtained solution, 3.96 g of 2,6-di-tert-butyl-p-cresol was added. Next, the solvent was removed by steam stripping, and the mixture was dried with a heat roll adjusted to 110° C. to obtain a solid conjugated diene rubber. The obtained conjugated diene rubber is also referred to as conjugated diene rubber 4.

[0119] Formula (4) [ka]

[0120] In formula (4), R 1 is a hydrocarbyl group having 1 to 20 carbon atoms, R 2 is a hydrocarbyloxy group having 1 to 20 carbon atoms, R 3 is an alkanediyl group having 1 to 20 carbon atoms, 2 is the group "*-C(R 5 )=N-" or the group "*-N=C(R 5 )-" (However, R 5 is a hydrogen atom or a hydrocarbyl group, and "*" is R 4 It indicates that the bond is bonded to the R. 4 is an m-valent hydrocarbyl group having 1 to 20 carbon atoms, or an m-valent group having 1 to 20 carbon atoms which has at least one atom selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms and has no active hydrogen. n is an integer of 1 to 3, and m is an integer of 2 to 10. In the formula, multiple R 1 , R 2 , R 3 , A 2 , n may be the same or different.

[0121] The conjugated diene rubber 4 is a reaction product between a conjugated diene polymer, which is a copolymer of butadiene and styrene, and a modifier, and is a modified conjugated diene rubber having a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, which is derived from the modifier.

[0122] [Weight average molecular weight, weight average intrinsic viscosity, styrene content, vinyl content, glass transition temperature] The conjugated diene rubbers synthesized as described above (conjugated diene rubbers 3 and 4 (comparison), conjugated diene rubbers 5 and 6) were 10% , IVw, IVw 10%, St, Vn, St+Vn, and Tg are shown in Table 2. The results of E581 used as conjugated diene rubber 1 (comparison) and NS560 used as conjugated diene rubber 2 (comparison) are also shown in Table 2. Details of E581 etc. will be described later. In Table 2, the "right side" refers to the right side of equation (1), "3.1 × 10 -6 ×Mw 10% represents the value "-2.77". In Table 2, "Applicable" of formula (1) indicates whether formula (1) is applicable or not. Specifically, "A" is IVw 10% satisfies formula (1), and "B" is IVw 10% does not satisfy equation (1). In Table 2, "Applicable" of formula (2) indicates whether formula (2) is applicable or not. Specifically, "A" is IVw 10% satisfies formula (2), and "B" is IVw 10% does not satisfy equation (2). In Table 2, "St+Vn" in formula (3) represents the above-mentioned St+Vn.

[0123] [Table 2]

[0124] As shown in Table 2, the conjugated diene rubber 1 (comparison) does not satisfy the formulas (1) and (2), and therefore does not fall under the above-mentioned specific conjugated diene rubber. Conjugated diene rubber 2 (comparison) satisfies formula (2) but does not satisfy formula (1), and therefore does not fall under the category of the above-mentioned specific conjugated diene rubber. Conjugated diene rubbers 3 and 4 (comparison) satisfy formula (1). As described above, conjugated diene rubbers 3 and 4 (comparison) are modified conjugated diene rubbers having specific modifying groups. However, conjugated diene rubbers 3 and 4 (comparison) do not satisfy formula (2), and therefore do not fall under the above-mentioned specific conjugated diene rubbers. On the other hand, as shown in Table 2, all of the conjugated diene rubbers 5 to 6 satisfy the formula (1) and the formula (2). As described above, all of the conjugated diene rubbers 5 to 6 are modified conjugated diene rubbers having a specific modifying group. Therefore, all of the conjugated diene rubbers 5 to 6 correspond to the above-mentioned specific conjugated diene rubber.

[0125] [Preparation of rubber composition for tires] The components in Tables 3 and 4 below were mixed in the compositions (parts by mass) shown in the tables. Specifically, first, the components other than sulfur and the vulcanization accelerator in Tables 3 and 4 were mixed in a 1.8 L internal mixer at 160°C or less for 5 minutes, and a master batch was discharged. Then, sulfur and the vulcanization accelerator were added to the master batch, and the mixture was mixed at 100°C or less using an open roll to produce each rubber composition for tires.

[0126] [evaluation] The following evaluations were carried out for each of the obtained rubber compositions for tires. The results are shown in Tables 3 and 4.

[0127] [Rolling performance] Each of the obtained rubber compositions for tires was press-vulcanized in a mold (15 cm x 15 cm x 0.2 cm) at 160°C for 40 minutes to produce each vulcanized rubber sheet. Then, for each of the obtained vulcanized rubber sheets, tan δ(60°C) was measured under conditions of an elongation deformation strain rate of 10%±2%, a frequency of 20 Hz, and a temperature of 60°C in accordance with JIS K6394:2007 using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho, Ltd.), and the reciprocal of tan δ(60°C) was calculated. The results were expressed as an index with the reciprocal of tan δ (60°C) of the standard example set to 100. In the present invention, the rolling performance (low rolling resistance) is considered to be excellent when the index is equal to or greater than 100. A larger index indicates better rolling performance.

[0128] [Wet performance] Each of the obtained rubber compositions for tires was press-vulcanized in a mold (15 cm x 15 cm x 0.2 cm) at 160°C for 40 minutes to produce each vulcanized rubber sheet. Then, for each of the obtained vulcanized rubber sheets, tan δ(0°C) was measured under conditions of an elongation deformation rate of 10%±2%, a frequency of 20 Hz, and a temperature of 0°C using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K6394:2007, and the reciprocal of tan δ(0°C) was calculated. The results were expressed as an index with tan δ (0°C) of the standard example set at 100. In the present invention, wet performance is deemed to be excellent when the index is equal to or greater than 100. A larger index indicates better wet performance.

[0129] [Wear resistance] Each of the obtained rubber compositions for tires was press-vulcanized in a mold (15 cm x 15 cm x 0.2 cm) at 160°C for 40 minutes to produce each vulcanized rubber sheet. Then, for the obtained vulcanized rubber sheets, the amount of wear was measured under conditions of a load of 15.0 kg (147.1 N) and a slip ratio of 25% using a Lambourn abrasion tester (manufactured by Iwamoto Seisakusho Co., Ltd.) in accordance with JIS K6264-2:2005. The results were expressed as an index, with the reciprocal of the amount of wear of the standard sample set to 100. In the present invention, the abrasion resistance is deemed to be excellent when the index is 105 or more. A larger index indicates more excellent abrasion resistance.

[0130] [Aging resistance performance] Each of the obtained rubber compositions for tires was press-vulcanized in a mold (15 cm x 15 cm x 0.2 cm) at 160°C for 40 minutes to produce each vulcanized rubber sheet. The obtained vulcanized rubber sheets were used as they were for tensile tests, and the vulcanized rubber sheets were subjected to heat aging treatment at 80°C for 168 hours and then subjected to tensile tests. From each of the vulcanized rubber sheets, dumbbell JIS No. 3 test pieces were prepared in accordance with JIS K6251. Using the obtained test pieces, tensile tests were performed at room temperature (20°C) and a tensile speed of 500 mm / min to measure the 100% tensile stress (M100) at 100% elongation. From the results obtained, the 100% tensile stress of the test piece that had not been subjected to heat aging treatment was defined as T0, and the 100% tensile stress of the test piece that had been subjected to heat aging treatment (80°C, 168 hours) was defined as T1, and the rate of change in 100% tensile stress (M100) due to the presence or absence of heat aging treatment was calculated as Δ=(T1-T0) / T0×100[%]. The results were expressed as an index with the reciprocal of the rate of change Δ in the standard case set at 100. In the present invention, the aging resistance is considered to be excellent when the index is 108 or more. A higher index indicates better aging resistance.

[0131] [Table 3]

[0132] [Table 4]

[0133] Details of each component in Tables 3 and 4 are as follows. NR: Natural rubber. SIR20 manufactured by PT.KIRANA SAPTA, Tg: -65℃. Unmodified Conjugated diene rubber 1 (for comparison): Asahi Kasei E581 (terminally modified solution-polymerized SBR having hydroxyl groups at the terminals) (does not satisfy formulas (1) and (2) and therefore does not fall under the above-mentioned specific conjugated diene rubber) Conjugated diene rubber 2 (for comparison): NS560 (terminal-modified SBR) manufactured by Zeon Corporation (does not satisfy formula (1) and therefore does not fall under the category of the specific conjugated diene rubber described above) Conjugated diene rubbers 3 to 4 (comparison): Conjugated diene rubbers 3 to 4 synthesized as described above (do not satisfy formula (2) and therefore do not fall under the specific conjugated diene rubbers described above) Conjugated diene rubbers 5-6: Conjugated diene rubbers 5-6 synthesized as described above (these are modified diene rubbers having specific modifying groups and satisfy the formulas (1) and (2), and therefore correspond to the specific conjugated diene rubbers described above) CB: Tokai Carbon Co., Ltd. SEAT3 (HAF carbon black, nitrogen adsorption specific surface area (N2SA): 79m 2 / g) ·Silica: Solvay ZEOSIL 1165MP (CTAB adsorption specific surface area: 160m 2 / g) Silane coupling agent 1 (Si69): Si69 manufactured by Evonik. Bis(3-triethoxysilylpropyl)tetrasulfide Silane coupling agent 2 (NXT): A silane coupling agent having a thioester group. 3-octanoylthio-1-propyltriethoxysilane (structure below) (manufactured by Momentive Performance Materials, Inc.) [ka] Silane coupling agent 3: A silane coupling agent having a polysiloxane skeleton and containing a sulfide group and a mercapto group, represented by the following average composition formula: Average composition formula (-C3H6-S4-C3H6-) 0.071 (-C8H 17 ) 0.571 (-OC2H5) 1.50 (-C3H6SH) 0.286 SiO 0.75 . Silane coupling agent 3 was prepared as follows. In a 2L separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, 107.8g (0.2mol) of bis(triethoxysilylpropyl)tetrasulfide (KBE-846 manufactured by Shin-Etsu Chemical Co., Ltd.), 190.8g (0.8mol) of γ-mercaptopropyltriethoxysilane (KBE-803 manufactured by Shin-Etsu Chemical Co., Ltd.), 442.4g (1.6mol) of octyltriethoxysilane (KBE-3083 manufactured by Shin-Etsu Chemical Co., Ltd.), and 190.0g of ethanol were placed, and then a mixed solution of 37.8g (2.1mol) of 0.5N hydrochloric acid and 75.6g of ethanol was dropped at room temperature. Then, the mixture was stirred at 80°C for 2 hours. Then, the mixture was filtered, and 17.0g of 5% KOH / EtOH solution was dropped and stirred at 80°C for 2 hours. After that, the mixture was concentrated under reduced pressure and filtered to obtain 480.1 g of a brown transparent liquid polysiloxane. Measurement by GPC revealed that the average molecular weight was 840 and the average degree of polymerization was 4.0 (predetermined degree of polymerization: 4.0). Furthermore, the mercapto equivalent was measured by the acetic acid / potassium iodide / potassium iodate addition-sodium thiosulfate solution titration method, and it was found to be 730 g / mol, which was the mercapto group content as set. From the above, the obtained polysiloxane is represented by the following average composition formula. Therefore, the obtained polysiloxane corresponds to the sulfur-containing silane coupling agent represented by the above-mentioned average composition formula (X). (-C3H6-S4-C3H6-) 0.071 (-C8H 17 ) 0.571 (-OC2H5) 1.50 (-C3H6SH) 0.286 SiO 0.75 The obtained polysiloxane is also referred to as silane coupling agent 3. Alkyltriethoxysilane: Octyltriethoxysilane (KBE-3083, Shin-Etsu Chemical Co., Ltd.) Process oil: Showa Shell Sekiyu Extract No. 4 S Thermoplastic resin 1: Terpene resin. YS Resin TO125 manufactured by Yasuhara Chemical Co., Ltd. (aromatic modified terpene resin, softening point: 125°C) Thermoplastic resin 2: C5 / C9 resin. ENEOS RD104 Vulcanization accelerator (CZ): Sancerer CM-G (sulfenamide type) manufactured by Sanshin Chemical Industry Co., Ltd. · Vulcanization accelerator (DPG): Sumitomo Chemical Co., Ltd. Soxinol DG (guanidine type) Sulfur: Shikoku Chemical Industry Co., Ltd.'s Myucron OT-20

[0134] As can be seen from Tables 3 and 4, all of Examples 1 to 14, which contain a diene rubber containing a specific amount of a specific conjugated diene rubber, silica, a silane coupling agent, and an alkyltriethoxysilane, exhibited excellent rolling performance, wet performance, wear resistance, and aging resistance. Comparing Examples 1 and 2 (comparison between embodiments differing only in the type of rubber component), Example 1, which contains conjugated diene rubber 5 as the specific conjugated diene rubber, exhibited better abrasion resistance. Example 2, which contains conjugated diene rubber 6 as the specific conjugated diene rubber, exhibited better wet performance and heat aging resistance. In addition, comparing Example 1 and Example 3 (comparison between embodiments differing only in the rubber component content), Example 1, in which the proportion of the specific conjugated diene rubber in the diene rubber was 50 mass% or more, showed superior rolling performance, wet performance and heat aging resistance. Moreover, a comparison between Examples 1 and 4 (a comparison between embodiments differing only in the amount of silane coupling agent) showed that Example 1, which contained a large amount of silane coupling agent, exhibited superior abrasion resistance. Furthermore, a comparison between Example 1 and Examples 7 to 9, and a comparison between Example 5 and Examples 10 to 12 (a comparison between embodiments that differ only in that a thermoplastic resin is further contained), shows that Examples 7 to 9, which further contain a thermoplastic resin, exhibited at least better wet performance than Example 1, and Examples 10 to 12 exhibited at least better wet performance than Example 5. In addition, comparing Examples 1, 5 and 6 (comparison between embodiments in which only the type of silane coupling agent is different), Example 5, in which the silane coupling agent contains NXT, exhibited better aging resistance than Examples 1 and 6. Comparing Examples 7 to 9 with Examples 10 to 12 (comparison between embodiments in which only the type of silane coupling agent is different), when a thermoplastic resin was further contained, Examples 10 to 12 in which the silane coupling agent contained NXT exhibited better rolling performance and wet performance than Examples 7 to 9. Comparing with Examples 13, 10, and 14 (comparison between embodiments differing only in the amount of alkyltriethoxysilane), Example 10 exhibited better rolling performance, wet performance, wear resistance, and aging resistance than Example 13, and also exhibited better wear resistance and aging resistance than Example 14.

[0135] On the other hand, the standard example and Comparative Examples 1 to 3, which contain a modified diene rubber other than the specific conjugated diene rubber instead of the specific conjugated diene rubber, Comparative Example 4, which contains the specific conjugated diene rubber but does not contain alkyltriethoxysilane, and Comparative Example 5, in which the content of the specific conjugated diene rubber in the diene rubber is less than 25% by mass, were insufficient in at least one of the rolling performance, wet performance, wear resistance, and aging resistance. [Explanation of symbols]

[0136] 1 Bead section 2 Sidewall 3 Tire tread 4 Carcass layer 5 Bead Core 6 Bead Filler 7 Belt layer 8 Rim cushion

Claims

1. The composition contains a diene rubber including a modified conjugated diene rubber (A1), silica, a silane coupling agent, and an alkyltriethoxysilane, The modified conjugated diene rubber (A1) satisfies the following formula (1) and the following formula (2) and has a modifying group containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent to the silicon atom, The rubber composition for tires, wherein the proportion of the modified conjugated diene rubber (A1) in the diene rubber is 25 mass % or more. [Vw １０％ ≦3.1×10 －６ ×Mw １０％ -2.77 (1) [Vw １０％ <4.7 (2) IVw in formula (1) and formula (2) １０％ and Mw in formula (1) １０％ The details are as follows: The modified conjugated diene rubber is subjected to gel permeation chromatography measurement using a differential refractive index detector and a viscosity detector as detectors. The weight average molecular weight (Mw) was calculated using the high molecular weight portion of the chromatogram peak that was 10% of the total peak area. １０％ The weight-average intrinsic viscosity determined using the high molecular weight portion of the peak in the chromatogram obtained by the viscosity detector, which is 10% of the total peak area, is defined as IVw １０％ Here, the unit of the weight average intrinsic viscosity is dL / g.

2. The modified conjugated diene rubber (A1) is a star-shaped structure having three or more branches, at least one branch of which has a moiety derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group; The rubber composition for a tire according to claim 1 , wherein the portion further has a main chain branched structure.

3. Further containing a modified conjugated diene rubber (A2) other than the modified conjugated diene rubber (A1), The rubber composition for tires according to claim 1, wherein a total proportion of the modified conjugated diene rubber (A1) and the modified conjugated diene rubber (A2) in the diene rubber is 70 mass % or more.

4. The Mw １０％ is 2.0 x 10 ６ The rubber composition for tires according to claim 1 .

5. The rubber composition for tires according to claim 1, wherein the content of the silica is 50 parts by mass or more based on 100 parts by mass of the diene rubber.

6. The rubber composition for tires according to claim 1, wherein the silane coupling agent includes 3-octanoylthio-1-propyltriethoxysilane or a sulfur-containing silane coupling agent represented by the following average composition formula (X), and the content of the silane coupling agent is 2 to 20 mass % of the content of the silica. (A) ａ (B) ｂ (C) ｃ (D) ｄ (R １ ) ｅ SiO （４－２ａ－ｂ－ｃ－ｄ－ｅ） / 2 (X) In formula (X), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 10 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R １ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a to e satisfy the relational expressions 0≦a<1, 0<b<1, 0<c<3, 0<d<1, 0≦e<2, 0<2a+b+c+d+e<4.

7. Further containing a thermoplastic resin, 2. The rubber composition for tires according to claim 1, wherein the thermoplastic resin comprises at least one selected from the group consisting of terpene resins, C5 / C9 resins, C9 resins, DCPD resins, DCPD / C9 resins, hydrogenated C5 / C9 resins, hydrogenated C9 resins, hydrogenated DCPD resins, and hydrogenated DCPD / C9 resins.

8. Further containing a thermoplastic resin, 2. The rubber composition for tires according to claim 1, wherein the thermoplastic resin comprises at least two resins selected from the group consisting of terpene resins, C5 / C9 resins, C9 resins, DCPD resins, DCPD / C9 resins, hydrogenated C5 / C9 resins, hydrogenated C9 resins, hydrogenated DCPD resins, and hydrogenated DCPD / C9 resins.

9. A tire produced using the rubber composition for tires according to any one of claims 1 to 8.

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