Rubber composition for tire, and tire

Abstract

To provide a rubber composition for a tire exhibiting excellent extrusion processability, wet performance and snow performance, and a tire produced by using the rubber composition for a tire.SOLUTION: The rubber composition for a tire contains 100 pts. mass of a rubber component containing 30 pts. mass or more of an aromatic vinyl-conjugated diene copolymer rubber satisfying a specific formula, 30 pts. mass or more of silica, a specific resin, and a silane coupling agent having a protected mercapto group, wherein the specific resin is a resin having an aromatic proton ratio of 20% or more and a parameter S of 300 or more. Here, kn, α, and An are specific parameters in the total ion chromatogram obtained by pyrolysis gas chromatography-mass spectrometry of the resin.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, rubber compositions for tires that contain petroleum resins in order to control properties such as viscoelasticity have been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-002387 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, from the viewpoint of safety and the like, there has been a demand for both wet performance (braking performance on wet road surfaces) and snow performance (braking performance on snowy and icy road surfaces) to be achieved at a high level. In this context, the present inventors have studied the rubber composition for tires described in Patent Document 1, and have found that the above performances are not necessarily sufficient. Furthermore, it has been found that extrusion processability may also be insufficient.

[0005] In view of the above circumstances, the present invention aims to provide a rubber composition for tires that exhibits excellent extrusion processability and exhibits excellent wet performance and snow performance 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 present inventors have found that the above-mentioned problems can be solved by using a specific aromatic vinyl-conjugated diene copolymer rubber, silica, a specific resin, and a specific silane coupling agent in combination, and have thus 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 rubber composition contains 100 parts by mass of a rubber component containing 30 parts by mass or more of an aromatic vinyl-conjugated diene copolymer rubber, 30 parts by mass or more of silica, a specific resin, and a silane coupling agent having a protected mercapto group, The aromatic vinyl-conjugated diene copolymer rubber satisfies the following formula (1): The rubber composition for tires, wherein the specific resin is a resin having a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and a parameter S described below of 300 or more. 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 aromatic vinyl-conjugated diene copolymer rubber is subjected to gel permeation chromatography measurement using a differential refractive index detector and a viscosity detector. The weight average molecular weight (Mw) is determined using the high molecular weight portion of the chromatogram peak obtained by the differential refractive index detector, which is 10% of the total peak area. 10% In addition, 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 area of ​​the entire peak, is defined as IVw. 10% However, the unit of weight average intrinsic viscosity is dL / g. (2) The CTAB adsorption specific surface area of ​​the silica is 140 m 2 / g or more, The rubber composition for a tire according to (1) above, wherein the content of the silica per 100 parts by mass of the rubber component is 180 parts by mass or less. (3) The rubber composition for tires according to (1) or (2) above, wherein the content of the specific resin per 100 parts by mass of the rubber component is 5 parts by mass or more and 50 parts by mass or less. (4) A tire manufactured using the rubber composition for a tire according to any one of (1) to (3) above. [Effects of the Invention]

[0008] As will be described below, according to the present invention, it is possible to provide a rubber composition for a tire that exhibits excellent extrusion processability and exhibits excellent wet performance and snow performance when made into a tire, and a tire manufactured using the rubber composition for a tire. [Brief explanation of the drawings]

[0009] [Figure 1] This is an example of a GPC chromatogram. [Figure 2] 1 is a total ion chromatogram obtained by pyrolysis GC-MS of resin A. [Figure 3] 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 INVENTION

[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. 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 wet performance and snow performance when made into a tire are also simply referred to as "wet performance" and "snow performance", respectively.

[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") is The rubber composition contains 100 parts by mass of a rubber component containing 30 parts by mass or more of an aromatic vinyl-conjugated diene copolymer rubber, 30 parts by mass or more of silica, a specific resin, and a silane coupling agent having a protected mercapto group, The aromatic vinyl-conjugated diene copolymer rubber satisfies the following formula (1), In the rubber composition for tires, the specific resin is a resin having a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and a parameter S (described later) of 300 or more.

[0012] It is believed that the composition of the present invention can solve the above-mentioned problems because of its structure. The reason for this is not clear, but is presumed to be as follows.

[0013] As described above, the composition of the present invention uses a specific aromatic vinyl-conjugated diene copolymer rubber in combination with a specific resin (a resin having a ratio of aromatic hydrocarbon-derived protons determined by NMR (nuclear magnetic resonance) method of 20% or more and a parameter S described below of 300 or more). The specific resin has a structure similar to that of an aromatic vinyl-conjugated diene copolymer rubber because the ratio of aromatic hydrocarbon-derived protons (hereinafter also referred to as "aromatic proton ratio") is 20% or more. The specific resin has a parameter S (hereinafter also referred to as "S value") described below of 300 or more. Here, the S value is a parameter related to the retention coefficient of peaks (however, peaks with a retention coefficient of 6 or less) and area ratio in a total ion chromatogram (hereinafter also referred to as "TIC") obtained by pyrolysis gas chromatography mass spectrometry (hereinafter also referred to as "pyrolysis GC-MS") using a packing (structure shown below) similar in structure to the aromatic vinyl-conjugated diene copolymer rubber, and represents the retention of the monomers constituting the resin to the packing. Since the specific resin has an S value of a specific value or more, it is considered to have extremely high compatibility with the aromatic vinyl-conjugated diene copolymer rubber.

[0014] [ka]

[0015] Furthermore, since the composition of the present invention contains a specific silane coupling agent, the dispersibility of silica is high. As described above, the aromatic vinyl-conjugated diene copolymer rubber satisfies the formula (1) described below. Formula (1) defines 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' studies have revealed that rubbers that satisfy formula (1) have excellent processability.

[0016] As a result, the components in the composition of the present invention are compatible and dispersible to an extremely high degree, which is believed to result in excellent extrusion processability, wet performance, and snow performance.

[0017] Each component contained in the composition of the present invention will be described below.

[0018] [1] Rubber component The composition of the present invention contains a rubber component containing an aromatic vinyl-conjugated diene copolymer rubber (hereinafter also referred to as "specific conjugated diene rubber") that satisfies the formula (1) described below. The rubber component may contain a rubber component other than the specific conjugated diene rubber. The rubber component may be modified with an alkoxy group, an alkoxysilyl group, or the like.

[0019] [Specific conjugated diene rubber] The specific conjugated diene rubber is an aromatic vinyl-conjugated diene copolymer rubber that satisfies the formula (1) described below.

[0020] [Skeleton] The skeleton of the specific conjugated diene rubber is a polymer having repeating units derived from an aromatic vinyl and repeating units derived from a conjugated diene.

[0021] <Aromatic vinyl> A specific example of the aromatic vinyl is styrene.

[0022] <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.

[0023] <Other Monomers> The skeleton of the specific conjugated diene rubber may have repeating units other than repeating units derived from aromatic vinyl and repeating units derived from conjugated dienes. Examples of monomers that form such repeating units (other monomers) include vinyl monomers and alkenes (e.g., ethylene, propylene, butene). Examples of vinyl monomers include acrylonitrile and the specific branching agent described below.

[0024] <Example> Specific examples of the skeleton include styrene-butadiene rubber (SBR), styrene-isoprene copolymer rubber, etc. Among these, SBR is preferred because it provides better effects of the present invention.

[0025] [Formula (1)] The specific conjugated diene rubber satisfies the following formula (1). Formula (1) defines 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 with small molecular size relative to their molecular weight, such as those with branches, tend to satisfy formula (1). The reason for limiting the formula to the high molecular weight side is that it has a large impact on the physical properties of the entire polymer.

[0026] IVw 10% ≦3.1×10 -6 ×Mw 10% -2.77 (1)

[0027] Mw in formula (1) 10% and IVw 10% is calculated as follows: The aromatic vinyl-conjugated diene copolymer 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 (Mw) is determined using the high molecular weight portion of the peak in the chromatogram obtained by the differential refractive index detector, which is 10% of the total peak area. 10% In addition, 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 area of ​​the entire peak, is defined as IVw. 10% However, the unit of weight average intrinsic viscosity is dL / g.

[0028] Hereinafter, Mw in formula (1) 10% and IVw 10% This will be explained in more detail.

[0029] As described above, the aromatic vinyl-conjugated diene copolymer 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.

[0030] The eluent used was toluene containing 5 mmol / L triethylamine. Three columns packed with polystyrene gel (manufactured by Tosoh Corporation under the trade names "TSKgel G4000HXL," "TSKgel G5000HXL," and "TSKgel G6000HXL") were connected together. The sample to be measured was dissolved in toluene to a concentration of 1 mg / mL to prepare the measurement solution. 100 μL of the measurement solution was injected into the GPC measurement device and measured at an oven temperature of 40°C and a toluene flow rate of 1 mL / min.

[0031] The weight average molecular weight is calculated using the high molecular weight side (the side with a shorter elution time) which accounts for 10% of the total area of ​​the peaks (peaks derived from aromatic vinyl-conjugated diene copolymer 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's say.

[0032] In addition, among the peaks (peaks derived from aromatic vinyl-conjugated diene copolymer rubber) in the chromatogram (horizontal axis: elution time, vertical axis: signal intensity) obtained by the viscosity detector, the weight-average intrinsic viscosity is determined using the part on the high molecular weight side (the side with the shorter elution time) which accounts for 10% of the total peak area. The weight-average intrinsic viscosity thus obtained is referred to as IVw 10% Let's say. 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.

[0033] An example of a GPC chromatogram (horizontal axis: elution time, vertical axis: signal intensity) is shown in Figure 1. The Mw peak was calculated using P1, which is the high molecular weight portion (shorter elution time) that accounts for 10% of the area of ​​the entire peak, P0. 10% and IVw 10% Ask for.

[0034] Examples of a method for making the aromatic vinyl-conjugated diene copolymer rubber satisfy the formula (1) include 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 below.

[0035] Mw 10% is preferably 100,000 to 10,000,000, and more preferably 1,000,000 to 5,000,000, because the effects of the present invention are more excellent.

[0036] IVw 10% is preferably 2 to 8, and more preferably 4 to 6, because the effects of the present invention are more excellent.

[0037] [Specific modifying group] The specific conjugated diene rubber preferably has a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom and an oxygen atom adjacent to the silicon atom, for the reason that the effects of the present invention are more excellent. The specific modifying group may be present at any of the terminal, main chain, or side chain of the aromatic vinyl-conjugated diene copolymer rubber. The specific modifying group preferably contains a silicon atom and an oxygen atom adjacent thereto as an alkoxysilyl group, because this provides a more excellent effect of the present invention. 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 this provides better effects of the present invention.

[0038] [Formula (2)] The specific conjugated diene rubber preferably satisfies the following formula (2) for the reason that the effects of the present invention are more excellent.

[0039] St+Vn≦50 (2)

[0040] In formula (2), St represents the proportion (mass%) of repeating units derived from styrene relative to the entire specific conjugated diene rubber (hereinafter also referred to as the "styrene amount"), and Vn represents the proportion (mass%) of repeating units of 1,2-vinyl structure derived from a conjugated diene (e.g., butadiene) relative to the entire specific conjugated diene rubber (hereinafter also referred to as the "vinyl amount").

[0041] St+Vn is preferably 10 to 45, and more preferably 25 to 45, because the effects of the present invention are more excellent.

[0042] St is preferably 5 to 40, more preferably 10 to 35, and even more preferably 15 to 30, because the effects of the present invention are more excellent.

[0043] Vn is preferably 5 to 30, and more preferably 10 to 20, because the effects of the present invention are more excellent.

[0044] [Molecular weight] The weight average molecular weight (Mw) of the specific conjugated diene rubber is preferably 100,000 to 2,000,000, and more preferably 200,000 to 1,300,000, for reasons of better effects of the present invention. The weight average molecular weight (Mw) of the specific conjugated diene rubber is measured in the same manner as described above except that the entire peak is used. 10% is the same as

[0045] [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, more preferably from -80°C to -45°C, for reasons of better effects of the present invention. The glass transition temperature can be adjusted by, for example, 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.

[0046] [Preferred embodiment 1] The specific conjugated diene rubber preferably has a star structure with three or more branches, more preferably 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 even more preferably is an aromatic vinyl-conjugated diene copolymer rubber represented by the following formula (A):

[0047] [ka]

[0048] 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 an aromatic vinyl-conjugated diene copolymer chain, and n represents an integer of 3 or more.

[0049] 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 this provides a better effect of the present invention.

[0050] As described above, P represents an aromatic vinyl-conjugated diene copolymer chain. Multiple Ps may be the same or different. The definition, specific examples and preferred embodiments of the aromatic vinyl-conjugated diene copolymer chain are the same as those of the skeleton of the specific conjugated diene rubber described above.

[0051] As described above, n represents an integer of 3 or greater. There is no particular upper limit to n, but it is preferably 30 or less in order to obtain better effects of the present invention.

[0052] [Preferred embodiment 2] When the specific conjugated diene rubber has a star structure with three or more branches, at least one branched chain (aromatic vinyl-conjugated diene copolymer chain) of the star structure preferably has a portion derived from a specific branching agent described later, and the portion preferably has a further main chain branched structure, for reasons of better effects of the present invention. The main chain branched structure refers to a structure in which a branched chain (aromatic vinyl-conjugated diene copolymer 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 aromatic vinyl-conjugated diene copolymer chain) extends from the branch point.

[0053] [Content] The content of the specific conjugated diene rubber per 100 parts by mass of the rubber component is 30 parts by mass or more, that is, the proportion of the specific conjugated diene rubber in the rubber component is 30% by mass or more. The above proportion is preferably 40% by mass or more, and more preferably 50% by mass or more, for reasons of superior effects of the present invention. The upper limit of the above proportion is not particularly limited, and is 100% by mass.

[0054] [Method of manufacturing specific conjugated diene rubber] When the specific conjugated diene rubber has a specific modifying group, the production method is preferably a method comprising the following steps (1) to (2) (hereinafter also referred to as the "production method of the present invention"), because the effects of the present invention are more excellent. (1) A polymerization step in which aromatic vinyl and conjugated diene-containing monomers are polymerized by anionic polymerization to obtain an aromatic vinyl-conjugated diene copolymer. (2) A modification step in which the aromatic vinyl-conjugated diene copolymer 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 modifying agent") to obtain an aromatic vinyl-conjugated diene copolymer having a specific modifying group.

[0055] [Polymerization process] The polymerization step is a step in which aromatic vinyl-conjugated diene copolymers are obtained by polymerizing monomers containing aromatic vinyl and conjugated dienes by anionic polymerization.

[0056] <Anionic polymerization> The anionic polymerization is not particularly limited, but anionic polymerization using an organolithium compound as an initiator is preferred because it provides better effects of the present invention.

[0057] The organolithium compound is not particularly limited, and specific examples thereof include monoorganolithium compounds such as n-butyllithium (n-BuLi), sec-butyllithium, tert-butyllithium, n-propyllithium, isopropyllithium, and benzyllithium; 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-tirithiobenzene, and 1,3,5-tirithio-2,4,6-triethylbenzene. Among these, the monoorganolithium compounds n-butyllithium, sec-butyllithium, and tert-butyllithium are preferred, and n-butyllithium is more preferred, due to the superior effects of the present invention.

[0058] The amount of the organolithium compound used is not particularly limited, but is preferably 0.001 to 10 mol % relative to the monomer, because this provides a better effect of the present invention.

[0059] <Monomer> Specific examples and preferred embodiments of the aromatic vinyl and conjugated diene-containing monomers used in the polymerization step are the same as those of the aromatic vinyl, conjugated diene and other monomers in the skeleton of the specific conjugated diene rubber described above.

[0060] (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 better 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.

[0061] (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.

[0062] (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 a better effect of the present invention.

[0063] <Polar compounds> In the polymerization step, a polar compound may be added. This allows the monomers to be copolymerized randomly. Polar compounds also tend to be useful as vinylating agents for controlling the microstructure of conjugated dienes. They also tend to be effective in accelerating the polymerization reaction.

[0064] 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.

[0065] (Amount used) The amount of polar compound used is preferably 0.01 moles or more and 100 moles or less per mole of the initiator, because this provides a better effect of the present invention.

[0066] [Modification step] The modification step is a step of reacting the aromatic vinyl-conjugated diene copolymer obtained in the polymerization step with a modifier (specific modifier) ​​containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto, to obtain an aromatic vinyl-conjugated diene copolymer having a specific modifying group.

[0067] In the modification step, it is believed that the active terminal of the aromatic vinyl-conjugated diene copolymer 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 believed that the active terminal is bonded to the silicon atom of the alkoxysilyl group, and the alkoxy group is released. Furthermore, when the aromatic vinyl-conjugated diene copolymer obtained in the polymerization step has a portion derived from the specific branching agent, in addition to the above-mentioned active terminal, the alkoxysilyl group or halosilyl group in the above portion is also thought to react with the specific modifying agent (e.g., alkoxysilyl group). Furthermore, the alkoxysilyl group or halosilyl group in the above portion is also thought to react with the active terminal of another aromatic vinyl-conjugated diene copolymer. As a result, the aromatic vinyl-conjugated diene copolymer having a portion derived from the specific branching agent will have a main chain branched structure (another aromatic vinyl-conjugated diene copolymer chain) in the above portion.

[0068] <Specific denaturant> The specific modifier is a compound containing a nitrogen atom, a silicon atom and an oxygen atom adjacent thereto. For the reason that the effects of the present invention are 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 an 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 aromatic vinyl-conjugated diene copolymers together.

[0069] (Example) Specific examples of the specific modifying agent 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 and tertiary amines having an alkoxysilyl group and a group containing a cyclic silazane structure, such as -(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.

[0070] (Amount used) The amount of the specific modifier used is preferably 0.01 to 1% by mass, more preferably 0.02 to 0.2% by mass, based on the conjugated diene, because this provides a better effect of the present invention.

[0071] [Other steps] The manufacturing 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 (for example, methanol) is added, and a solvent removal step in which the solvent is removed by steam stripping.

[0072] [Other rubber components] The rubber component may contain a rubber component (rubber component) other than the specific conjugated diene rubber. Examples of such other rubber components include natural rubber (NR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber other than the specific conjugated diene rubber, isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene-butadiene rubber (SBR) and styrene-isoprene copolymer rubber.

[0073] [Average Tg] The glass transition temperature (hereinafter also referred to as "average Tg") of the entire rubber component is higher than -80°C and not higher than -45°C. The average Tg of the rubber component is preferably −75° C. or higher and −45° C. or lower, and more preferably −70° C. or higher and −50° C. or lower, for reasons of better effects of the present invention. The average Tg of the rubber components is the sum (weighted average value of glass transition temperatures) of the glass transition temperatures (Tg) of the individual rubber components multiplied by the mass fraction of each rubber component.

[0074] [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.

[0075] [2] Silica The composition of the present invention contains 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. Biomass-derived silica such as rice husks may also be used. The silica may be used alone or in combination of two or more types.

[0076] [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 for the reason that the effect of the present invention is superior, it is preferred that the specific surface area be 70 to 300 m 2 / g, and 110 to 250m 2 / g, and more preferably 140 to 200m 2 / g is more preferred. Here, the CTAB adsorption specific surface area is a value measured in accordance with JIS K6430:2008, Appendix G.

[0077] [Content] In the composition of the present invention, the content of silica is 30 parts by mass or more per 100 parts by mass of the rubber component. For reasons of better effects of the present invention, the content is preferably 10 to 300 parts by mass, more preferably 50 to 200 parts by mass, and further preferably 100 to 180 parts by mass.

[0078] [3] Specific resin The composition of the present invention contains a resin (specific resin) having a ratio of aromatic hydrocarbon-derived protons (aromatic proton ratio) of 20% or more as determined by NMR and a parameter S (S value) described below of 300 or more.

[0079] [Aromatic proton ratio] The aromatic proton ratio of the specific resin is 20% or more. The aromatic proton ratio is preferably 22% or more, more preferably 24% or more, even more preferably 26% or more, and particularly preferably 28% or more, because the effects of the present invention are more excellent. There is no particular upper limit to the ratio, but because the effects of the present invention are more excellent, it is preferably 80% or less, and more preferably 50% or less.

[0080] The aromatic proton ratio is determined as follows. Resin is dissolved in a solvent 1 The H-NMR spectrum is measured. In the spectrum, the ratio of the area of ​​the peaks of protons derived from aromatic hydrocarbons (aromatic rings) to the total area of ​​the peaks of protons derived from the resin is calculated, and this is taken as the aromatic proton ratio. For example, when the resin is a styrene polymer (polystyrene), the aromatic proton ratio is the ratio of the peak area of ​​protons derived from benzene rings to the sum of the peak areas of protons derived from polystyrene.

[0081] [S value] The specific resin has a parameter S (S value) of 300 or more.

[0082]

number

[0083] where k n represents the retention coefficient of the nth peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and α represents the retention coefficient of the nth peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and k n represents the n above of the peak with the maximum retention factor of ≦6.0, and A n is k n It represents the ratio (%) of the area of ​​the nth peak to the total area of ​​peaks that satisfy the condition ≦6.0.

[0084] The S value is preferably 330 or more, and more preferably 350 or more, because the effects of the present invention are more excellent. There is no particular upper limit to the S value, but the S value is preferably 500 or less, and more preferably 400 or less, because the effects of the present invention are more excellent.

[0085] The pyrolysis gas chromatography mass spectrometry (pyrolysis GC-MS) is carried out under the following conditions.

[0086] (conditions) - Instrument name: Shimadzu GCMS-QP2020 Pyrolysis equipment name: Frontier Labs Double Shot Pyrolyzer PY-2020iD ·Thermal decomposition temperature: 550℃ ·Inlet temperature: 320℃ Column used: 5% diphenyldimethl polysiloxane (GL Sciences UA-5) Column size: Length 30m, inner diameter 0.25mm, film thickness 0.25μm Method (column temperature conditions): 70°C (3 min) → Heat at 10°C / min (25 min) → Final temperature 320°C Carrier gas: Ultra-high purity helium gas (total flow rate: 104 mL / min, column flow rate: 1 mL / min) ·Injection volume: 1μL

[0087] A specific example of how to calculate the S value is shown below. 2 is a total ion chromatogram (TIC) obtained by pyrolysis GC-MS of Resin A, which will be described later. The pyrolysis GC-MS conditions were as described above. As shown in Figure 2, the TIC of Resin A has two peaks. The retention factor k1 of the peak with the shortest retention time (the left peak) is 1.7, and the retention factor k2 of the peak with the second shortest retention time (the right peak) is 2.8. Since the retention factors of both peaks are 6.0 or less, k nThe peak with the largest retention factor that satisfies ≦6.0 is the right peak. Because the right peak is the second peak from the shortest retention time, α in the parameter S is 2. Furthermore, the ratio A1 of the area of ​​the left peak to the sum of the areas of the two peaks is 40(%), and the ratio A2 of the area of ​​the right peak to the sum of the areas of the two peaks is 60(%). Therefore, the S value of Resin A is calculated as 1.7×40+2.8×60=236.

[0088] One example of a method for achieving an S value of 300 or greater is to polymerize a resin using a monomer containing an aromatic hydrocarbon having a polymerizable group, and increase the proportion of components in the aromatic hydrocarbons that have a high retention coefficient (the aforementioned retention coefficient) (preferably components with a retention coefficient of 2 or greater, more preferably components with a retention coefficient of 3 or greater). To enhance the effects of the present invention, the proportion is preferably 50% by mass or greater, more preferably 70% by mass or greater, and even more preferably 90% by mass or greater. The upper limit of the proportion is not particularly limited, and is 100% by mass. Since aliphatic hydrocarbons are likely to decompose at the decomposition temperature (550°C) of the pyrolysis GC-MS described above, the presence of aliphatic hydrocarbons in the monomers that make up the resin is thought to have little effect on the S value.

[0089] [Preferred embodiment] The monomer constituting the specific resin preferably contains an aromatic hydrocarbon having a polymerizable group (for example, a vinyl group, an isopropenyl group, etc.) because this provides a better effect of the present invention. Specific examples of the aromatic hydrocarbon include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, indene, and methylindene. Among these, vinyltoluene, isopropenyltoluene, indene, and methylindene are preferred, and isopropenyltoluene, indene, and methylindene are more preferred, because they provide better effects of the present invention.

[0090] For reasons of better effects of the present invention, the retention coefficient of the aromatic hydrocarbons (the retention coefficient described above) is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no particular upper limit to the retention coefficient, but for reasons of better effects of the present invention, it is preferably 6 or less, and more preferably 5 or less.

[0091] The monomers constituting the specific resin preferably contain aliphatic hydrocarbons (preferably aliphatic hydrocarbons containing unsaturated double bonds) in addition to the above-mentioned aromatic hydrocarbons. The aliphatic hydrocarbon may be linear, branched, or cyclic. Specific examples of the aliphatic hydrocarbons include aliphatic hydrocarbons that constitute C5 fractions, such as isoprene and cyclopentadiene.

[0092] When the monomer constituting the specific resin contains aliphatic hydrocarbons (e.g., C5 fractions) in addition to the aromatic hydrocarbons described above, the content of the aromatic hydrocarbons in the monomer is preferably 30 to 99 mass%, more preferably 50 to 97 mass%, and even more preferably 70 to 95 mass%, for reasons of better effects of the present invention. When the monomer constituting the specific resin contains aliphatic hydrocarbons (e.g., C5 fraction) in addition to the aromatic hydrocarbons described above, the content of the aliphatic hydrocarbons in the monomer is preferably 1 to 70 mass%, more preferably 3 to 50 mass%, and even more preferably 5 to 30 mass%, for reasons of better effects of the present invention.

[0093] [Molecular weight] The weight average molecular weight (Mw) of the specific resin is preferably 100 or more and less than 100,000, more preferably 200 to 50,000, and even more preferably 500 to 10,000, for reasons of better effects of the present invention.

[0094] [Content] In the composition of the present invention, the content of the specific resin relative to the content of the specific conjugated diene rubber (hereinafter also referred to as "specific resin / SBR") is 1 to 200% by mass. The specific resin / SBR content is preferably 2 to 150% by mass, and more preferably 3 to 100% by mass, because this provides better effects of the present invention.

[0095] In the composition of the present invention, the content of the specific resin is preferably 1 to 200 parts by mass, more preferably 2 to 150 parts by mass, even more preferably 3 to 100 parts by mass, and particularly preferably 5 to 50 parts by mass, per 100 parts by mass of the rubber component, because this provides better effects of the present invention.

[0096] [4] Specific silane coupling agents The composition of the present invention contains a silane coupling agent having a protected mercapto group (blocked mercapto group) (hereinafter also referred to as a "specific silane coupling agent").

[0097] [Silane coupling agents] The silane coupling agent 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. Of these, an alkoxy group is preferred because the effects of the present invention are more excellent. When the hydrolyzable group is an alkoxy group, the number of carbon atoms in 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 alkoxy groups having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, and a propoxy group. 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, and a blocked mercapto group (protected mercapto group) (for example, an octanoylthio group). Of 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.

[0098] [Protected mercapto group] As described above, the specific silane coupling agent has a protected mercapto group (blocked mercapto group). The protected mercapto group is a group represented by *-SR (R: substituent, *: bonding position). Examples of the substituent include aliphatic hydrocarbon groups, aromatic hydrocarbon groups (aryl groups), and combinations thereof. The aliphatic hydrocarbon groups may be linear, branched, or cyclic. Specific examples of the aliphatic hydrocarbon groups include linear or branched alkyl groups (particularly having 1 to 30 carbon atoms), linear or branched alkenyl groups (particularly having 2 to 30 carbon atoms), and linear or branched alkynyl groups (particularly having 2 to 30 carbon atoms). Examples of the aromatic hydrocarbon groups include aromatic hydrocarbon groups having 6 to 18 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl. The substituent is preferably an aliphatic hydrocarbon group, more preferably an alkyl group, for the reason that the effects of the present invention are more excellent. The number of carbon atoms in the aliphatic hydrocarbon group (particularly the alkyl group) is preferably 1 to 20, more preferably 5 to 10, for the reason that the effects of the present invention are more excellent. A carbon atom in the aliphatic hydrocarbon group (particularly the alkyl group) may be substituted with -O-, -C(=O)-, -C(=O)-O-, -OC(=O)-O-, -S-, -S(=O)-, -SO2-, -NR- (R: hydrogen atom or substituent, a group combining these groups, etc.). The above substituent is preferably an acyl group (particularly an octanoyl group) because this provides better effects of the present invention.

[0099] [Specific example] A specific example of the specific silane coupling agent is 3-octanoylthiopropyltriethoxysilane (the compound shown below).

[0100] [ka]

[0101] [Content] In the composition of the present invention, the content of the specific silane coupling agent is not particularly limited, but in order to obtain better effects of the present invention, it is preferably 1 to 20 mass % relative to the content of the silica described above, and more preferably 5 to 15 mass %.

[0102] In the composition of the present invention, the content of the specific silane coupling agent is not particularly limited, but in order to obtain better effects of the present invention, it is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass, per 100 parts by mass of the rubber component described above.

[0103] [5] Optional component The composition of the present invention may contain components (optional components) other than the above-mentioned components, if necessary. Examples of such components include various additives commonly used in rubber compositions, such as resins other than the specific resin, fillers other than silica (preferably carbon black or aluminum hydroxide), silane coupling agents other than the specific silane coupling agents, thermally expandable microcapsules, 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.

[0104] [Carbon black] The composition of the present invention preferably 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 types. 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.

[0105] [N2SA] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, but is preferably 50 to 200 m for the reason that the effect of the present invention is more excellent. 2 / g, and 70 to 150m 2 / g is more preferred. Here, the nitrogen adsorption specific surface area (N2SA) is the amount of nitrogen adsorbed onto 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."

[0106] [Content] In the composition of the present invention, the content of carbon black is not particularly limited, but in order to achieve better effects of the present invention, it is preferably 1 to 100 parts by mass, and more preferably 2 to 50 parts by mass, per 100 parts by mass of the rubber component described above.

[0107] [6] 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 apparatus (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.

[0108] [II] Tires The tire of the present invention is a tire manufactured using the composition of the present invention described above. 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.

[0109] 3 is a partial cross-sectional schematic view of a tire showing one example of an embodiment of the tire of the present invention, although the tire of the present invention is not limited to the embodiment shown in FIG.

[0110] In FIG. 3, 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 with fiber cords embedded therein is mounted, and the ends of this carcass layer 4 are folded back and wrapped around the bead core 5 and bead filler 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 around the entire circumference of the tire. In addition, a rim cushion 8 is disposed in the bead portion 1 at the 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 composition of the present invention described above.

[0111] The tire of the present invention can be manufactured, for example, by a conventionally known method. The gas to be filled into the tire can be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium. [Example]

[0112] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0113] [Synthesis of specific conjugated diene rubber] Each specific conjugated diene rubber was synthesized as follows.

[0114] [Specific conjugated diene rubber 1]

[0115] <Polymerization process> An autoclave equipped with a stirrer was charged under a nitrogen atmosphere with cyclohexane at 1000 g / h (hour), tetramethylethylenediamine at 0.023 g / h, 1,3-butadiene at 176.4 g / h, 1-butene at 0.406 g / h, and styrene at 23.6 g / h, and then n-butyllithium was continuously added at 1.43 mmol / h to initiate polymerization at 70 °C. When the polymerization was sufficiently stable, 1-(trimethoxysilyl)-4-vinylbenzene (branching agent) was added at 0.02 g / h and the mixture was stirred to allow the reaction to proceed. The branching agent corresponds to the specific branching agent described above.

[0116] <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 0.08 g / h, and the mixture was stirred to react.

[0117] Thereafter, methanol was added as a polymerization terminator to obtain a solution containing SBR.

[0118] To the resulting solution, 1.14 parts by mass of Irganox 1520L (manufactured by BASF) was added as an antioxidant per 100 parts by mass of SBR, and the solvent was then removed by steam stripping. The resulting mixture was vacuum dried at 60°C for 24 hours to obtain solid SBR. The resulting SBR is also referred to as specific conjugated diene rubber 1.

[0119] The specific conjugated diene rubber 1 is a reaction product of SBR, which is a copolymer of butadiene, styrene, and a branching agent, with a modifier, and is an SBR having a modifying group (specific modifying group) derived from the modifier, which includes a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto. The specific conjugated diene rubber 1 has a star structure with three or more branches, with the modifying group as the 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 (SBR chain).

[0120] [Specific conjugated diene rubber 2] A solid SBR was obtained in the same manner as for specific conjugated diene rubber 1, except that the amount of each component was changed as shown in Table 1. The obtained SBR is also referred to as specific conjugated diene rubber 2.

[0121] The specific conjugated diene rubber 2 is a reaction product of SBR, which is a copolymer of butadiene, styrene, and a branching agent, with a modifier, and is an SBR having a modifying group (specific modifying group) derived from the modifier, which includes a nitrogen atom, a silicon atom, and an oxygen atom adjacent thereto. The specific conjugated diene rubber 2 has a star structure with three or more branches, with the modifying group as the 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 (SBR chain).

[0122] [Table 1]

[0123] [Weight average molecular weight, weight average intrinsic viscosity, styrene content, vinyl content, glass transition temperature] Regarding the specific conjugated diene rubbers 1 and 2 synthesized as described above, Mw, Mw 10% , IVw, IVw 10% The values ​​of St, Vn, and glass transition temperature (Tg) are shown in Table 2. The values ​​of HPR840, which will be described later, are also shown in Table 2. In Table 2, the "right side" of Equation (1) refers to the right side of Equation (1), "3.1 x 10 -6 ×Mw 10% represents the value "-2.77". In addition, in Table 2, "Suitable / Inapplicable" for formula (1) indicates whether formula (1) is satisfied or not. Specifically, "A" indicates that formula (1) is satisfied, and "B" indicates that formula (1) is not satisfied. In addition, in Table 2, "St+Vn" in formula (2) represents the above-mentioned St+Vn.

[0124] [Table 2]

[0125] As shown in Table 2, all of the specific conjugated diene rubbers 1 and 2 satisfy the formula (1). Therefore, the specific conjugated diene rubbers 1 and 2 are aromatic vinyl-conjugated diene copolymer rubbers that satisfy the formula (1), and correspond to the above-mentioned specific conjugated diene rubbers. On the other hand, as shown in Table 2, HPR840 does not satisfy formula (1) and therefore does not fall under the category of the above-mentioned specific conjugated diene rubber.

[0126] [Production of rubber composition for tires] The components shown in Tables 3 and 4 below were blended in the proportions (parts by mass) shown in the tables. Specifically, first, the components except for sulfur and the vulcanization accelerator were kneaded in a 1.7-liter internal mixer for 5 minutes, and then released when the temperature reached 150°C to obtain a master batch. Next, sulfur and the vulcanization accelerator were kneaded into the obtained master batch using an open roll to obtain a rubber composition for tires.

[0127] [evaluation] The resulting rubber compositions for tires were evaluated as follows.

[0128] [Wet performance] The obtained rubber composition for tires was vulcanized at 170°C for 15 minutes using a mold of a predetermined shape (inner dimensions: length 150 mm, width 150 mm, thickness 2 mm) to prepare a vulcanized rubber sheet. The vulcanized rubber sheet thus obtained was measured for tan δ at 0° C. under conditions of an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K6394:2007. The results are shown in Tables 3 and 4. The results are expressed as an index, with Comparative Example 1 being 100. The larger the index, the more excellent the wet performance. In practice, an index of 100 or more is preferable.

[0129] [Snow performance] The storage modulus (E'(-20°C)) of the vulcanized rubber sheets prepared as described above was measured at -20°C using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K6394:2007 under conditions of an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz. The reciprocal of E' (-20°C) is shown in Tables 3 and 4. The results are expressed as an index, with the reciprocal of E' (-20°C) in Comparative Example 1 set to 100. The larger the index, the better the snow performance. In practice, an index greater than 100 is preferable.

[0130] [Extrusion processability] The obtained rubber composition for a tire was subjected to accelerated aging at 60°C for 24 hours. Thereafter, in accordance with JIS K6300, the composition was preheated at 100°C for 1 minute using an L-type rotor, and the rotation of the rotor was started, and the viscosity was measured after 4 minutes. The results are shown in Tables 3 and 4. The results are expressed as an index, with Comparative Example 1 being 100. The smaller the index, the better the extrusion processability. In practice, an index of less than 100 is preferred.

[0131] [Table 3]

[0132] [Table 4]

[0133] In Tables 3 and 4, the "aromatic proton ratio" and "S value" columns indicate the aromatic proton ratio and S value of the resin (resins A to G) used in each example, respectively.

[0134] 〔resin〕 The resins in Tables 3 and 4 are as follows. Resins D to F have an aromatic proton ratio of 20% or more and an S value of 300 or more, and therefore all fall under the above-mentioned specific resins. On the other hand, resins A to B and G have an S value of less than 300, and therefore none of them fall under the above-mentioned specific resins. Furthermore, resin C has an aromatic proton ratio of less than 20%, and therefore does not fall under the above-mentioned specific resins. The Mw of resins A to G is all less than 100,000. Resin A: Resin obtained by thermal polymerization of α-methylstyrene and styrene in a 6 / 5 (mass ratio) ratio (aromatic proton ratio: 54%, S value: 236) Resin B: Resin obtained by thermal polymerization of styrene and indene in a 2 / 3 (mass ratio) ratio (aromatic proton ratio: 53%, S value: 283) Resin C: A resin obtained by thermal polymerization of C5 fraction and indene in a 4 / 1 (mass ratio) ratio (aromatic proton ratio: 12%, S value: 355) Resin D: A resin obtained by thermal polymerization of styrene, α-methylstyrene, vinyltoluene, indene, and isopropenyltoluene in a mass ratio of 3 / 14 / 68 / 13 / 2 (aromatic proton ratio: 37%, S value: 308, Mw: 1522). Resin E: A resin obtained by thermal polymerization of C5 fraction, styrene, α-methylstyrene, vinyltoluene, indene, isopropenyltoluene, and methylindene in a mass ratio of 100 / 3 / 4 / 24 / 28 / 9 / 32 (aromatic proton ratio: 25%, S value: 336, Mw: 1936). Resin F: A resin obtained by thermal polymerization of C5 fraction, indene, and methylindene in a mass ratio of 10 / 63 / 27 (aromatic proton ratio: 41%, S value: 390, Mw: 1037). Resin G: Tosoh Petrotack 90 (C5 / C9 resin) (aromatic proton ratio: 29%, S value: 272, Mw: 2000)

[0135] [Components other than resin] In Tables 3 and 4, the components other than the resin are as follows. Specific conjugated diene rubbers 1 to 2: Specific conjugated diene rubbers 1 to 2 synthesized as described above HPR840: ENEOS HPR840 (terminally modified styrene butadiene rubber with aminosilane structure) BR1220: Nipol BR1220 (butadiene rubber) manufactured by Nippon Zeon Co., Ltd. ·Silica 1: Solvay ZEOSIL 1165MP (CTAB adsorption specific surface area: 160m 2 / g) CB: Cabot Japan Show Black N339 Carbon Black Silane coupling agent A: 3-octanoylthiopropyltriethoxysilane (compound below) (corresponding to a specific silane coupling agent)

[0136] [ka] Silane coupling agent B: Evonik Si69 (not a specific silane coupling agent) Oil: Shell Lubricants Japan Extract No. 4 S Zinc oxide: Three types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. Stearic acid: NOF Corporation Beads Stearic Acid YR Anti-aging agent: Flexis 6PPD Sulfur: Tsurumi Chemical Industry Co., Ltd. Kinka-in oil-filled fine powder sulfur Vulcanization accelerator (CZ): Noccela CZ-G (CZ) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator (DPG): Sumitomo Chemical's Soxinol DG (DPG)

[0137] [Summary of Tables 3-4] As can be seen from Tables 3 and 4, Examples 1 to 6, which used a combination of a specific conjugated diene rubber, a specific resin, and a specific silane coupling agent, exhibited excellent wet performance, snow performance, and extrusion processability. Comparing Examples 1 to 3 (comparison of embodiments differing only in the type of specific resin), Examples 2 and 3, in which the specific resin had an S value of 330 or more, exhibited better wet and snow performance. Among them, Example 3, in which the specific resin had an S value of 350 or more, exhibited even better wet and snow performance. In addition, from a comparison between Example 3 and Example 4 (a comparison between embodiments in which the type of specific conjugated diene rubber is different), the IVw of the specific conjugated diene rubber 10% Example 3, in which St+Vn was 4.5 or more, exhibited better wet performance and snow performance. Furthermore, a comparison between Example 3 and Example 4 (comparison between embodiments in which different types of specific conjugated diene rubber were used) revealed that Example 4, in which the specific conjugated diene rubber had an St+Vn of 40 or more, exhibited better extrusion processability. Furthermore, comparing Example 3 with Examples 5 and 6 (comparison between embodiments differing only in the content of the specific resin), Examples 3 and 6, in which the content of the specific resin per 100 parts by mass of the rubber component was 10 parts by mass or more, showed better wet performance. Among them, Example 3, in which the content of the specific resin per 100 parts by mass of the rubber component was 40 parts by mass or less, showed better snow performance and extrusion processability.

[0138] On the other hand, Comparative Examples 1 to 4, which contained a resin other than the specific resin instead of the specific resin, Comparative Example 6, which contained a silane coupling agent other than the specific silane coupling agent instead of the specific silane coupling agent, and Comparative Example 7, in which the silica content per 100 parts by mass of the rubber component was less than 30 parts by mass, were insufficient in wet performance, snow performance, and extrusion processability.Furthermore, Comparative Example 5, in which the specific conjugated diene rubber content per 100 parts by mass was less than 30 parts by mass, was insufficient in snow performance and extrusion processability. [Explanation of symbols]

[0139] 1 Bead section 2 Sidewall 3 Tire tread 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Rim Cushion

Claims

1. The rubber composition contains 100 parts by mass of a rubber component containing 30 parts by mass or more of an aromatic vinyl-conjugated diene copolymer rubber, 30 parts by mass or more of silica, a specific resin, and a silane coupling agent having a protected mercapto group, The aromatic vinyl-conjugated diene copolymer rubber satisfies the following formula (1): The rubber composition for a tire, wherein the specific resin is a resin having a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and a parameter S below of 300 or more. [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 aromatic vinyl-conjugated diene copolymer 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 determined using the high molecular weight portion of the peak in the chromatogram obtained by the differential refractive index detector, which accounts for 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 area of ​​the entire peak, is defined as IVw. １０％ However, the unit of the weight average intrinsic viscosity is dL / g. [Equation 1] Here, k ｎ represents the retention coefficient of the n-th peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and α represents the retention coefficient of the n-th peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and k ｎ represents the n of the peak having the maximum retention factor of ≦6.0, and A ｎ is k ｎ It represents the ratio (%) of the area of ​​the nth peak to the total area of ​​peaks that satisfy the condition ≦6.

0.

2. The CTAB adsorption specific surface area of ​​the silica is 140 m ２ / g or more, The rubber composition for a tire according to claim 1, wherein the content of the silica per 100 parts by mass of the rubber component is 180 parts by mass or less.

3. The rubber composition for a tire according to claim 1, wherein the content of the specific resin per 100 parts by mass of the rubber component is 5 parts by mass or more and 50 parts by mass or less.

4. A tire manufactured using the rubber composition for tires according to any one of claims 1 to 3.

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