Rubber composition for tires and tire

Abstract

To provide a rubber composition for tires which exhibits excellent grip performance and circuit wear resistance when formed into a tire, and to provide a tire produced using the rubber composition for tires.SOLUTION: The rubber composition for tires contains a rubber component (A) containing a modified conjugated diene rubber (A1), a filler (B) comprising at least one selected from the group consisting of carbon black and silica, and a plasticizer (C) comprising at least one selected from the group consisting of an oil, a liquid polymer, and a thermoplastic resin. The modified conjugated diene rubber (A1) satisfies a specific formula and has a modified group having a nitrogen atom, a silicon atom, and an oxygen atom adjacent to the silicon atom. The rubber composition for tires contains the modified conjugated diene rubber (A1), the filler (B), and the plasticizer (C) in predetermined amounts.SELECTED DRAWING: Figure 2

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 fillers such as carbon black and silica from the viewpoint of improving performance have been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-28902 A Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, from the standpoint of safety and the like, there has been a demand for tires (particularly racing tires) to have further improved grip performance and circuit wear resistance (wear resistance under high severity conditions such as circuit driving). In this situation, the present inventors have studied the conventional rubber compositions for tires described in Patent Document 1 and the like, and have found that further improvements are desired in terms of grip performance and circuit wear resistance when made into tires.

[0005] In view of the above-mentioned circumstances, an object of the present invention is to provide a rubber composition for tires that exhibits excellent grip performance and circuit wear resistance when made into a tire, 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 discovered that the above-mentioned problems can be solved by blending a predetermined amount of a specific modified conjugated diene rubber as a rubber component and optimizing the types and blending amounts of a filler and a plasticizer, thereby arriving at the present invention. That is, the present inventors have found that the above problems can be solved by the following configuration.

[0007] [1] A rubber component (A) containing a modified conjugated diene rubber (A1); A filler (B) consisting of at least one selected from the group consisting of carbon black and silica; and a plasticizer (C) consisting of at least one selected from the group consisting of oil, liquid polymer, and thermoplastic resin, The modified conjugated diene rubber (A1) satisfies the following formula (1) and has a modifying group containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto, The proportion of the modified conjugated diene rubber (A1) in the rubber component (A) is 50% by mass or more, The content of the filler (B) is 100 parts by mass or more based on 100 parts by mass of the rubber component (A), The rubber composition for tires, wherein the content of the plasticizer (C) is 100 parts by mass or more per 100 parts by mass of the rubber component (A). IVw 10% ≦3.1×10 -6 ×Mw 10% -2.77 (1) Mw in formula (1) 10% and IVw 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 IVw10% However, the unit of weight average intrinsic viscosity is dL / g. [2] The rubber composition for tires according to [1], wherein the modified conjugated diene rubber (A1) satisfies the following formula (2): St+Vn≦50% by mass (2) In formula (2), St represents the ratio (mass%) of repeating units derived from styrene to the entire modified conjugated diene rubber, and Vn represents the ratio (mass%) of repeating units of 1,2-vinyl structure derived from conjugated diene to the entire modified conjugated diene rubber. [3] The modified conjugated diene rubber (A1), a star 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 [1] or [2], wherein the portion further has a main chain branched structure. [4] The filler (B) contains at least carbon black, The rubber composition for tires according to any one of [1] to [3], wherein the content of the carbon black is 100 to 200 parts by mass per 100 parts by mass of the rubber component (A). [5] The filler (B) contains at least carbon black, The nitrogen adsorption specific surface area of ​​the carbon black is 180m 2 / g or more. [6] The plasticizer (C) contains at least a thermoplastic resin, The rubber composition for tires according to any one of [1] to [5], 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. [7] A tire produced using the rubber composition for tires according to any one of [1] to [6]. [8] A tire as described in [7] above, which is used for racing. Effect of the Invention

[0008] As described below, according to the present invention, it is possible to provide a rubber composition for tires that exhibits excellent grip performance and circuit wear resistance when made into a tire, and a tire manufactured using the rubber composition for tires. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an example of a GPC chromatogram. [Diagram 2] FIG. 2 is a partial cross-sectional schematic view showing one example of an embodiment of a tire according to 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. Furthermore, with regard to a rubber composition for tires, the grip performance and circuit abrasion resistance when made into a tire are also simply referred to as "grip performance" and "circuit abrasion 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.

[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") contains a rubber component (A) containing a modified conjugated diene rubber (A1), a filler (B) consisting of at least one type selected from the group consisting of carbon black and silica, and a plasticizer (C) consisting of at least one type selected from the group consisting of oils, liquid polymers, and thermoplastic resins. The modified conjugated diene rubber (A1) is a conjugated diene rubber which satisfies the formula (1) described below and has a modifying group containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto. The proportion of the modified conjugated diene rubber (A1) in the rubber component (A) is 50% by mass or more. The content of the filler (B) is 100 parts by mass or more based on 100 parts by mass of the rubber component (A). The content of the plasticizer (C) is 100 parts by mass or more based on 100 parts by mass of the rubber component (A).

[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 the rubber component (A), a modified conjugated diene rubber (A1) (hereinafter also referred to as a "specific conjugated diene rubber") that satisfies the formula (1) described below and has a modifying group (hereinafter also referred to as a "specific modifying group") that contains a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto. 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, and the inventors have found that rubber that satisfies the formula (1) has excellent processability. Furthermore, it is believed that the specific modifying group of the specific conjugated diene rubber interacts with the filler. Therefore, in the composition of the present invention, the dispersibility of the filler is extremely high, which is believed to lead to excellent effects (grip performance and circuit wear resistance).

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

[0014] [1] Rubber component (A) The composition of the present invention contains a rubber component (A) containing a specific conjugated diene rubber. The composition of the present invention may contain a rubber component other than the specific conjugated diene rubber.

[0015] [Specific conjugated diene rubber] The specific conjugated diene rubber is a modified conjugated diene rubber (A1) which satisfies the formula (1) 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 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 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 and alkenes (e.g., ethylene, propylene, butene). 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 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 conjugated diene rubber is preferably SBR because the effects of the present invention are more excellent.

[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 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] [Formula (1)] The specific conjugated diene rubber satisfies the following formula (1). 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)

[0023] Mw in formula (1) 10% and IVw 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, Mw in formula (1) 10% and IVw 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% In order to obtain better effects of the present invention, the molecular weight is preferably 100,000 to 10,000,000, and more preferably 1,000,000 to 5,000,000.

[0032] IVw 10% is preferably 2 to 8, and more preferably 4 to 6, because the effects of the present invention are superior.

[0033] [Formula (2)] The specific conjugated diene rubber (modified conjugated diene rubber (A1)) preferably satisfies the following formula (2) for the reason that the grip performance becomes better.

[0034] St+Vn≦50% by mass (2)

[0035] In formula (2), 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] St+Vn is preferably from 10 to 45 mass %, and more preferably from 25 to 45 mass %, because the effects of the present invention are more excellent.

[0037] The content of St is preferably from 5 to 40% by mass, more preferably from 10 to 35% by mass, and further preferably from 15 to 30% by mass, because the effects of the present invention are more excellent.

[0038] Vn is preferably from 5 to 30% by mass, and more preferably from 10 to 20% by mass, 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 -30°C, and more preferably from -80°C to -45°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] The specific conjugated diene rubber (modified conjugated diene rubber (A1)) 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, for the reason that the effects of the present invention are more excellent, and further preferably is a conjugated diene rubber represented by the following formula (A).

[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] 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] [Content] The proportion of the specific conjugated diene rubber in the rubber component is 50% by mass or more. The above ratio is preferably 60% by mass or more, and more preferably 70% by mass or more, because the effects of the present invention are superior. The upper limit of the above proportion is not particularly limited, and is 100% by mass.

[0049] [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.

[0050] [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.

[0051] <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.

[0052] 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.

[0053] 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.

[0054] <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.

[0055] (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.

[0056] (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.

[0057] (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.

[0058] <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.

[0059] 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.

[0060] (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.

[0061] [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.

[0062] 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.

[0063] <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.

[0064] (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.

[0065] (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 better effects for the present invention.

[0066] [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.

[0067] [Other rubber components] The rubber component may contain a rubber component (rubber component) other than the specific conjugated diene rubber. Such other rubber components 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) and styrene-isoprene copolymer rubber.

[0068] [Average Tg] The glass transition temperature (hereinafter also referred to as "average Tg") of the entire rubber component is preferably -30°C or higher and 30°C or lower, and more preferably -20°C or higher and 20°C or lower, for the reason that the effects of the present invention are more excellent. The average Tg of the rubber components is the sum (weighted average value of glass transition temperatures) of the glass transition temperatures (Tg) of each rubber component multiplied by the mass fraction of each rubber component.

[0069] [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.

[0070] [2] Filler (B) The composition of the present invention contains a filler (B) consisting of at least one type selected from the group consisting of carbon black and silica. The content of the filler (B) is 100 parts by mass or more, preferably 100 to 200 parts by mass, and more preferably 100 to 150 parts by mass, based on 100 parts by mass of the rubber component. As the filler (B), it is preferable to use at least carbon black.

[0071] [Carbon black] The carbon black is not particularly limited, and any conventionally known carbon black can be used. As the carbon black, various grades can be used, for example, SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, SRF, etc. The above carbon black may be used alone or in combination of two or more types.

[0072] [N2SA] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, but is preferably 180 m 2 / g or more, and 180 to 350m 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."

[0073] [Content] When carbon black is used as the filler (B) in the composition of the present invention, the content of carbon black is preferably 100 to 200 parts by mass, and more preferably 100 to 150 parts by mass, per 100 parts by mass of the above-mentioned rubber component, because the effects of the present invention are more excellent.

[0074] [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, diatomaceous earth, etc. The above silica may be used alone or in combination of two or more kinds.

[0075] [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, but is preferably 100 to 180 m because the effect of the present invention is more excellent. 2 / g, and 130 to 165 m 2 It is more preferable that the molecular weight is / g. Here, the CTAB adsorption specific surface area is a value obtained by measuring the amount of CTAB adsorbed on the silica surface in accordance with JIS K6217-3:2001 "Part 3: Determination of specific surface area - CTAB adsorption method."

[0076] [Content] In the composition of the present invention, when silica is used as the filler (B), the content of silica is preferably 100 to 200 parts by mass, and more preferably 100 to 150 parts by mass, per 100 parts by mass of the above-mentioned rubber component, because the effects of the present invention are more excellent.

[0077] [3] Plasticizer (C) The composition of the present invention contains a plasticizer (C) consisting of at least one member selected from the group consisting of oils, liquid polymers, and thermoplastic resins. The content of the plasticizer (C) is 100 parts by mass or more, preferably 100 to 200 parts by mass, and more preferably 100 to 150 parts by mass, based on 100 parts by mass of the rubber component. As the plasticizer (C), it is preferable to use at least a thermoplastic resin, and it is more preferable to use an oil and a thermoplastic resin in combination.

[0078] [oil] The oil is not particularly limited, and any conventionally known oil can be used. Examples of the oil include oils that are usually blended in rubber compositions for tires, such as aromatic oils and process oils; and oil extenders that are added to emulsion-polymerized styrene-butadiene rubber.

[0079] [Content] In the composition of the present invention, when an oil and a thermoplastic resin are used in combination as the plasticizer (C), the content of the oil is preferably 5 to 50 parts by mass, and more preferably 10 to 40 parts by mass, per 100 parts by mass of the above-mentioned rubber component, because the effects of the present invention are more excellent.

[0080] [Liquid polymer] The liquid polymer is not particularly limited, and any conventionally known liquid polymer can be used. Examples of liquid polymers include liquid polyisoprene, liquid polybutadiene, and liquid styrene-butadiene rubber.

[0081] [Thermoplastic resin] The thermoplastic resin is not particularly limited, and any conventionally known thermoplastic resin can be used. 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.

[0082] The thermoplastic resin preferably contains 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, because this provides better effects for the present invention.

[0083] [Content] In the composition of the present invention, when oil and a thermoplastic resin are used in combination as the plasticizer (C), the content of the thermoplastic resin is preferably 50 to 150 parts by mass, and more preferably 75 to 125 parts by mass, per 100 parts by mass of the above-mentioned rubber component, because the effects of the present invention are more excellent.

[0084] [Resin ratio] In the composition of the present invention, when oil and a thermoplastic resin are used in combination as the plasticizer (C), the ratio of the thermoplastic resin to the total of the thermoplastic resin and the oil (hereinafter also referred to as the "resin ratio") is 50 mass% or more. The resin ratio is preferably 80% by mass or more because the effects of the present invention are more excellent.

[0085] [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 commonly used in rubber compositions, such as fillers other than carbon black and silica, silane coupling agents, thermally expandable microcapsules, zinc oxide (zinc white), stearic acid, antioxidants, waxes, processing aids, thermosetting resins, vulcanizing agents (e.g., sulfur), vulcanization accelerators (accelerators), and vulcanization activators.

[0086] [Silane coupling agents] The composition of the present invention preferably contains a silane coupling agent because the effects of the present invention are more excellent.

[0087] 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.

[0088] 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) (e.g., an octanoylthio group), and the like. 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.

[0089] The silane coupling agent is preferably a sulfur-containing silane coupling agent because the effects of the present invention are more excellent.

[0090] Specific examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, 3-octanoylthio-1-propyltriethoxysilane, and the like. One of these may be used alone, or two or more may be used in combination.

[0091] [Content] In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but is preferably 2 to 20 parts by mass per 100 parts by mass of the rubber component described above, because the effects of the present invention are more excellent.

[0092] In addition, in the composition of the present invention, the content of the silane coupling agent is preferably 1 to 20 mass % relative to the content of the above-mentioned filler (B) (particularly, silica), and more preferably 5 to 15 mass %, because the effects of the present invention are more excellent.

[0093] [Vulcanization accelerator] The composition of the present invention preferably contains a vulcanization accelerator because the effect of the present invention is more excellent. Examples of the vulcanization accelerator include sulfenamide-based, thiuram-based, and guanidine-based accelerators.

[0094] [Content] In the composition of the present invention, the content of the vulcanization accelerator is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, and further preferably 3 to 6 parts by mass, relative to 100 parts by mass of the above-mentioned rubber component, because the effects of the present invention are more excellent.

[0095] [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.

[0096] [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, which can be filled with air, an inert gas such as nitrogen, or other gases. The tire of the present invention is preferably a racing tire.

[0097] 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.

[0098] 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.

[0099] 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

[0100] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0101] [Synthesis of conjugated diene rubber] Each conjugated diene rubber was synthesized as follows.

[0102] [Conjugated diene rubber 1]

[0103] <Polymerization process> In a stirred autoclave, cyclohexane 1000g / h (hour), tetramethylethylenediamine 0.044g / h, 1,3-butadiene 169.9g / h, 1-butene 0.391g / h, and styrene 30.1g / 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 0.05g / h and the mixture was stirred to react. The branching agent corresponds to the specific branching agent described above.

[0104] <Denaturation process> To the solution discharged from the reactor outlet, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (modifier) ​​was added at 0.24 g / h, and the mixture was stirred to react.

[0105] Thereafter, methanol was added as a polymerization terminator to obtain a solution containing a conjugated diene rubber.

[0106] 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 1.

[0107] The conjugated diene rubber 1 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 1 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).

[0108] [Conjugated diene rubber 2] A solid conjugated diene rubber was obtained in the same manner as in the conjugated diene rubber 1, except that the amount of each component was changed as shown in Table 1 below. The obtained conjugated diene rubber is also referred to as conjugated diene rubber 2.

[0109] The conjugated diene rubber 2 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).

[0110] [Conjugated diene rubber 3] A solid conjugated diene rubber was obtained in the same manner as in the case of the conjugated diene rubber 1, except that the amount of each component was changed as shown in Table 1 below. The obtained conjugated diene rubber is also referred to as conjugated diene rubber 3.

[0111] 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).

[0112] [Table 1]

[0113] [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 1 to 3) and NS612 described later were 10% , IVw, IVw 10% , St, Vn, St+Vn, and glass transition temperature (Tg) are shown in Table 2 below. In Table 2 below, the "right side" of formula (1) is the right side of formula (1), "3.1 × 10 -6 ×Mw 10% represents the value "-2.77". In addition, in Table 2 below, "Suitable" in formula (1) indicates whether formula (1) is satisfied, and specifically, "A" indicates that formula (1) is satisfied, and "B" indicates that formula (1) is not satisfied. In addition, in the following Table 2, "St+Vn" in formula (2) represents the above-mentioned St+Vn.

[0114] [Table 2]

[0115] As shown in Table 2, all of the conjugated diene rubbers 1 to 3 satisfy formula (1). As described above, all of the conjugated diene rubbers 1 to 3 are modified conjugated diene rubbers having a specific modifying group. Therefore, all of the conjugated diene rubbers 1 to 3 correspond to the above-mentioned specific conjugated diene rubber. Note that the conjugated diene rubbers 1 and 2 also satisfy formula (2). Furthermore, as shown in Table 2 above, NS612 does not satisfy formula (1) and therefore does not fall under the category of the above-mentioned specific conjugated diene rubber.

[0116] [Preparation of rubber composition for tires] The components in Table 3 below were mixed in the composition (parts by mass) shown in the table. Specifically, first, the components other than sulfur and the vulcanization accelerator in Table 3 below were mixed in a 1.8 L internal mixer at 160°C or less for 5 minutes, and a master batch was discharged. Thereafter, 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.

[0117] [evaluation] The following evaluations were carried out for each of the obtained rubber compositions for tires.

[0118] [Grip performance (dry grip)] Using each of the obtained rubber compositions for tires, test tires were produced with a tire size of 245 / 40R19. The tires were mounted on a front-wheel drive vehicle with an engine displacement of 2300cc via an applicable rim, and the front-wheel drive vehicle was driven for two laps on a test course with a lap length of 10km. The controllability during steering was evaluated by a test driver and expressed as an index with the standard example being 100. The results are shown in Tables 3 and 4. In this evaluation, the higher the index, the higher the grip performance.

[0119] [Circuit abrasion resistance] Using each of the obtained rubber compositions for tires, test tires were produced with a tire size of 245 / 40R19. The tires were mounted on a front-wheel drive vehicle with an engine displacement of 2300cc via the applicable rim, and a test driver drove the front-wheel drive vehicle for five laps on a circuit with a circumference of 3.6km. The tire profile was measured before and after the run, and the amount of wear was calculated from the difference, and the reciprocal of the calculated amount was expressed as an index with the standard example being 100. The results are shown in Tables 3 and 4. In this evaluation, the higher the index, the higher the circuit wear resistance.

[0120] [Table 3]

[0121] Details of each component in Table 3 above are as follows. Conjugated diene rubbers 1 to 3: Conjugated diene rubbers 1 to 3 synthesized as described above NS612: NS612 manufactured by Zeon Corporation (solution polymerization SBR, Tg: -60°C) (does not satisfy formula (1) and therefore does not fall under the category of the specific conjugated diene rubber described above) Carbon black 1: Tokai Carbon Co., Ltd. Toka Black #5500 (conductive carbon black, nitrogen adsorption specific surface area (N2SA): 225 m 2 / g) Carbon black 2: Tokai Carbon Co., Ltd. SEAST 9 (SAF grade carbon black, nitrogen adsorption specific surface area (N2SA): 142 m 2 / g) Aroma oil: A / O Mix (manufactured by Sankyo Yuka Kogyo Co., Ltd.) Thermoplastic resin: Terpene phenol resin (Yasuhara Chemical YS Polyster T130) Stearic acid: Beads Stearic Acid YR (NOF Corporation) Zinc oxide: Three types of zinc oxide (manufactured by Seido Chemical Industry Co., Ltd.) Sulfur: Shikoku Chemical Industry Co., Ltd.'s Myucron OT-20 Vulcanization accelerator (CZ): Sancerer CM-G (sulfenamide type) manufactured by Sanshin Chemical Industry Co., Ltd. Vulcanization accelerator (TOT-N): Noccela TOT-N (thiuram type) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0122] As can be seen from Table 3 above, when the content of the filler (B) is less than 100 parts by mass per 100 parts by mass of the rubber component (A), both the grip performance and the circuit abrasion resistance are inferior (Comparative Example 1). It was also found that when the content of the plasticizer (C) was less than 100 parts by mass per 100 parts by mass of the rubber component (A), both the grip performance and the circuit abrasion resistance were inferior (Comparative Example 2). It was also found that when the proportion of the specific conjugated diene rubber (modified conjugated diene rubber (A1)) in the rubber component (A) was less than 50% by mass, the circuit abrasion resistance was poor (Comparative Example 3).

[0123] In contrast, it was found that when the ratio of the specific conjugated diene rubber (modified conjugated diene rubber (A1)) in the rubber component (A) is 50 mass% or more, the content of the filler (B) is 100 parts by mass or more per 100 parts by mass of the rubber component (A), and the content of the plasticizer (C) is 100 parts by mass or more per 100 parts by mass of the rubber component (A), both the grip performance and the circuit abrasion resistance are good (Examples 1 to 4). In particular, a comparison between Example 1 and Example 3 revealed that the grip performance was improved by using only the modified conjugated diene rubber satisfying the above formula (2) as the specific conjugated diene rubber (modified conjugated diene rubber (A1)). In addition, a comparison between Example 1 and Example 4 shows that the nitrogen adsorption specific surface area of ​​carbon black is 180 m 2 It was found that when the hardness was 1.0 / g or more, both the grip performance and the circuit abrasion resistance were improved. [Explanation of symbols]

[0124] 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. A rubber component (A) containing a modified conjugated diene rubber (A1); A filler (B) consisting of at least one selected from the group consisting of carbon black and silica; and a plasticizer (C) consisting of at least one selected from the group consisting of oil, liquid polymer, and thermoplastic resin, The modified conjugated diene rubber (A1) satisfies the following formula (1) and has a modifying group containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, The proportion of the modified conjugated diene rubber (A1) in the rubber component (A) is 50% by mass or more, The content of the filler (B) is 100 parts by mass or more based on 100 parts by mass of the rubber component (A), The rubber composition for tires, wherein the content of the plasticizer (C) is 100 parts by mass or more per 100 parts by mass of the rubber component (A). [Vw １０％ ≦3.1×10 －６ ×Mw １０％ -2.77 (1) Mw in formula (1) １０％ and IVw 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 rubber composition for tires according to claim 1 , wherein the modified conjugated diene rubber (A1) satisfies the following formula (2): St+Vn≦50% by mass (2) In formula (2), St represents the proportion (mass%) of repeating units derived from styrene to the entire modified conjugated diene rubber, and Vn represents the proportion (mass%) of repeating units of 1,2-vinyl structure derived from conjugated diene to the entire modified conjugated diene rubber.

3. 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.

4. The filler (B) contains at least carbon black, The rubber composition for tires according to claim 1, wherein the content of the carbon black is 100 to 200 parts by mass per 100 parts by mass of the rubber component (A).

5. The filler (B) contains at least carbon black, The carbon black has a nitrogen adsorption specific surface area of ​​180 m ２ The rubber composition for tires according to claim 1, wherein the viscosity is 100 / g or more.

6. The plasticizer (C) contains at least 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.

7. A tire produced using the rubber composition for tires according to any one of claims 1 to 6.

8. 8. The tire of claim 7, which is for racing use.

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