Rubber composition for tires and tires

Abstract

The present invention provides a rubber composition for tires that exhibits excellent extrusion processability and superior rolling and wet performance when made into tires, as well as tires manufactured using the above-mentioned rubber composition for tires. [Solution] A tire rubber composition comprising 100 parts by mass of conjugated diene rubber containing at least two types of aromatic vinyl-conjugated diene copolymer rubbers, 60 to 120 parts by mass of silica, a resin, a plasticizing oil, and a silane coupling agent, wherein the weight-average intrinsic viscosity of at least one type of aromatic vinyl-conjugated diene copolymer rubber is less than 2.5 dL / g, and the parameter P is 1.6 or higher. JPEG2026083739000011.jpg5131 Pol.Tg represents the Tg [°C] of the conjugated diene rubber, tanδ(Pol.Tg+70°C) represents the loss tangent at Pol.Tg+70°C, tanδ(Pol.Tg+130°C) represents the loss tangent at Pol.Tg+130°C, and E′(Pol.Tg+70°C) represents the storage modulus [MPa] at Pol.Tg+70°C.

Description

[Technical Field]

[0001] This invention relates to a rubber composition for tires and a tire. [Background technology]

[0002] Conventionally, from the viewpoint of improving performance, tire rubber compositions containing silica, a resin or oil, and a silane coupling agent are known (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-044764 [Overview of the project] [Problems that the invention aims to solve]

[0004] Recently, from an environmental perspective, there is a demand for further improvements in tire rolling performance. Furthermore, from a safety perspective, there is a demand for further improvements in wet performance. Additionally, from a manufacturing suitability perspective, there is a demand for improved extrusion processability. In this context, the inventors examined the tire rubber compositions described in Patent Document 1, etc., and found that further improvements are desirable considering the increasing demands that are expected in the future.

[0005] Therefore, in view of the above circumstances, the present invention aims to provide a tire rubber composition that exhibits excellent extrusion processability and excellent rolling performance and wet performance when made into a tire, as well as a tire manufactured using the above tire rubber composition. [Means for solving the problem]

[0006] As a result of diligent research into the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by using at least two types of aromatic vinyl-conjugated diene copolymer rubber, setting the weight-average intrinsic viscosity of at least one of the aromatic vinyl-conjugated diene copolymer rubbers to below a specific value, using a resin and a plasticizing oil in combination, and setting a specific parameter combining loss tangent and storage modulus to a predetermined value or higher, thus leading to the present invention. In other words, the inventors have found that the above problem can be solved by the following configuration.

[0007] (1) A conjugated diene rubber comprising at least two aromatic vinyl-conjugated diene copolymer rubbers, 60 to 120 parts by mass of silica, a resin, a plasticizing oil, and a silane coupling agent, The weight-average intrinsic viscosity of at least one of the above aromatic vinyl-conjugated diene copolymer rubbers is less than 2.5 dL / g. A rubber composition for tires in which the parameter P, described later, is 1.6 or higher. However, the weight-average intrinsic viscosity mentioned above is determined by performing gel permeation chromatography on aromatic vinyl-conjugated diene copolymer rubber using a viscosity detector, and using the entire peak of the chromatogram. (2) The CTAB relative to the entire silica is 135m 2 The tire rubber composition according to (1) above, wherein the proportion of silica less than or equal to / g is 80% by mass or less. (3) The tire rubber composition according to (1) or (2) above, wherein 100 parts by mass of the conjugated diene rubber comprises 20 parts by mass or more of aromatic vinyl-conjugated diene copolymer rubber in which the proportion of repeating units of 1,2-vinyl structure derived from the conjugated diene is 45% by mass or less. (4) The content of the above resin is 15 parts by mass or more per 100 parts by mass of the above conjugated diene rubber, The above resin 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. The ratio of the content of the above resin to the content of the above plasticizing oil is 2.6 or more in terms of mass ratio, and the rubber composition for a tire according to any one of the above (1) to (3). (5) The rubber composition for a tire according to any one of the above (1) to (4), wherein 100 parts by mass of the above conjugated diene rubber contains 20 parts by mass or more of an aromatic vinyl-conjugated diene copolymer rubber satisfying the following formula (1). (6) The rubber composition for a tire according to any one of the above (1) to (5), wherein the above silane coupling agent is a silane coupling agent having a protected mercapto group. (7) A tire produced using the rubber composition for a tire according to any one of the above (1) to (6). [Effect of the Invention]

[0008] As shown below, according to the present invention, it is possible to provide a rubber composition for a tire that is excellent in extrusion processability and exhibits excellent rolling performance and wet performance when made into a tire, and a tire produced using the above rubber composition for a tire. [Brief Description of the Drawings]

[0009] [Figure 1] It is an example of a GPC chromatogram. [Figure 2] It is a schematic partial cross-sectional view showing an example of an embodiment of the tire of the present invention. [Mode for Carrying Out the Invention]

[0010] Hereinafter, the rubber composition for a tire and the like of the present invention will be described. In the present specification, a numerical range represented by using "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. Furthermore, 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 each component refers to the total content unless otherwise specified. Furthermore, with respect to rubber compositions for tires, the rolling performance and wet performance when made into tires are also simply referred to as "rolling performance" and "wet 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 It contains 100 parts by mass of conjugated diene rubber containing at least two types of aromatic vinyl-conjugated diene copolymer rubber, 60 to 120 parts by mass of silica, a resin, a plasticizing oil, and a silane coupling agent. The weight-average intrinsic viscosity IVw of at least one of the above aromatic vinyl-conjugated diene copolymer rubbers is less than 2.5 dL / g. This is a rubber composition for tires in which the parameter P, described later, is 1.6 or higher. However, the weight-average intrinsic viscosity mentioned above is determined by performing gel permeation chromatography on aromatic vinyl-conjugated diene copolymer rubber using a viscosity detector, and using the entire peak of the chromatogram.

[0012] The following describes the components contained in the composition of the present invention.

[0013] [1] Conjugated diene rubber The conjugated diene rubber contained in the composition of the present invention comprises at least two aromatic vinyl-conjugated diene copolymer rubbers. The conjugated diene rubber may also contain conjugated diene rubbers other than aromatic vinyl-conjugated diene copolymer rubbers.

[0014] [Aromatic vinyl-conjugated diene copolymer rubber] Aromatic vinyl-conjugated diene copolymer rubber is a rubber made from a copolymer of aromatic vinyl and conjugated diene.

[0015] [Amjonomic vinyl] Specific examples of aromatic vinyls include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, divinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, and vinylpyridine. Among these, styrene is preferred because it exhibits superior effects compared to the present invention.

[0016] [Conjugated diene] Specific examples of conjugated dienes include butadiene (e.g., 1,3-butadiene), isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, and 1,3-pentadiene. Among these, 1,3-butadiene is preferred because it exhibits superior effects compared to the present invention.

[0017] [Specific examples] Specific examples of aromatic vinyl-conjugated diene copolymer rubbers include styrene-butadiene rubber (SBR) and styrene-isoprene rubber. Among these, SBR is preferred because it exhibits superior effects compared to the present invention.

[0018] [Ammonium vinyl content] The ratio of repeating units derived from aromatic vinyl (especially styrene) to the total aromatic vinyl-conjugated diene copolymer rubber (hereinafter also referred to as "aromatic vinyl content," and also as "styrene content" when the aromatic vinyl is styrene) is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, and even more preferably 20 to 33% by mass, for the reasons that the effects of the present invention are superior.

[0019] [Vinyl quantity] The ratio of repeating units of the 1,2-vinyl structure derived from the conjugated diene (especially butadiene) to the total aromatic vinyl-conjugated diene copolymer rubber (hereinafter also referred to as "vinyl amount") is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, even more preferably 10 to 30% by mass, and particularly preferably 15 to 20% by mass, for which the effects of the present invention are superior.

[0020] [Weight average intrinsic viscosity] The weight-average intrinsic viscosity (hereinafter also referred to as "IVw") of at least one of the aromatic vinyl-conjugated diene copolymer rubbers is less than 2.5 dL / g. In particular, it is preferable that it is 2.3 dL / g or less. The lower limit of IVw is not particularly limited, but it is preferable that it is 1.0 dL / g or more for the reasons that the effects of the present invention are better.

[0021] Furthermore, at least one additional IVw from the above aromatic vinyl-conjugated diene copolymer rubber is preferably 2.5 dL / g or more, for the reason that the effects of the present invention are superior. The upper limit of the above IVw is not particularly limited, but it is preferably 5.0 dL / g or less, for the reason that the effects of the present invention are superior.

[0022] The above IVw is the weight-average intrinsic viscosity obtained by performing gel permeation chromatography on aromatic vinyl-conjugated diene copolymer rubber using a viscosity detector, and utilizing the entire peak of the chromatogram. The specific measurement method for weight-average intrinsic viscosity is described below, except that the entire peak is used. 10% It is the same as this.

[0023] [Content] The content of aromatic vinyl-conjugated diene copolymer rubber in 100 parts by mass of the above-mentioned conjugated diene rubber is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 70 parts by mass or more, for reasons that the effects of the present invention are superior. The upper limit is not particularly limited, and is 100 parts by mass.

[0024] [Preferred Embodiment] The 100 parts by mass of the above-mentioned conjugated diene rubber preferably contains 20 parts by mass or more of aromatic vinyl-conjugated diene copolymer rubber in which the proportion of repeating units of the 1,2-vinyl structure derived from the conjugated diene (vinyl content) is 45% by mass or less, for the reason that the effects of the present invention are superior.

[0025] [Other conjugated diene rubbers] The conjugated diene rubber may include conjugated diene rubbers other than aromatic vinyl-conjugated diene copolymer rubber (hereinafter also referred to as "other conjugated diene rubbers"). Examples of such conjugated diene rubbers include natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Among these, butadiene rubber is preferred because it exhibits superior effects compared to the present invention.

[0026] [Content] The content of other conjugated diene rubbers in 100 parts by mass of conjugated diene rubber is preferably 50 parts by mass or less, and more preferably 30 parts by mass or less, for the reasons that the effects of the present invention are superior.

[0027] When the conjugated diene rubber contains butadiene rubber, the amount of butadiene rubber in 100 parts by mass of the conjugated diene rubber is preferably 10 to 40 parts by mass, and more preferably 20 to 30 parts by mass, for the reasons that the effects of the present invention are superior.

[0028] [Specific conjugated diene rubber] For reasons that the effects of the present invention are superior, it is preferable that the conjugated diene rubber contains a conjugated diene rubber that satisfies formula (1) described later (hereinafter also referred to as "specific conjugated diene rubber").

[0029] [Body structure] The backbone of specific conjugated diene rubbers is a polymer having repeating units derived from conjugated dienes.

[0030] <Conjugated Diene> Specific examples and preferred embodiments of the conjugated diene are the same as those of the conjugated diene in the aromatic vinyl-conjugated diene copolymer described above.

[0031] <Other monomers> The backbone of a specific conjugated diene rubber may have repeating units other than those derived from the conjugated diene. 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 aromatic vinyls (e.g., styrene), acrylonitrile, and specific branching agents described later.

[0032] <Specific example> Specific examples of the rubber skeleton include natural rubber (NR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber, isoprene rubber (IR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Examples of aromatic vinyl-conjugated diene copolymer rubbers include styrene-butadiene rubber (SBR) and styrene-isoprene rubber. The above-mentioned conjugated diene rubber is preferably an aromatic vinyl-conjugated diene copolymer rubber, and more preferably SBR, for the reasons that the effects of the present invention are superior.

[0033] [Specific modified group] The specific conjugated diene rubber is preferably one that has a modified group (specific modified group) containing a nitrogen atom, a silicon atom, and an oxygen atom adjacent to the silicon atom, for better performance of the present invention. The specific modified group is thought to interact with silica. The specific modifying group may be located at the end, main chain, or side chain of the conjugated diene rubber. For the reason that the effects of the present invention are more excellent, the specific modified group preferably contains a silicon atom and an oxygen atom adjacent thereto as an alkoxysilyl group. The alkoxysilyl group is -Si(OR1) n (R2) 3-n (where R1 is an alkyl group, R2 is a hydrogen atom or an alkyl group, and n is an integer from 1 to 3). For the reason that the effects of the present invention are more excellent, the specific modified group preferably contains a nitrogen atom as an amino group (primary to tertiary amino group). For the reason that the effects of the present invention are more excellent, the specific modified group is preferably a group derived from a specific modifier described later.

[0034] [Formula (1)] The specific conjugated diene rubber is a conjugated diene rubber that 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. Polymers with a small molecular size relative to the molecular weight, such as those having branches, tend to satisfy formula (1). The reason for limiting to the high molecular weight side is that the influence on the physical properties of the entire polymer is large.

[0035] IVw 10% ≦3.1×10 -6 ×Mw 10% -2.77 (1)

[0036] Mw in formula (1) 10% and IVw 10% are determined as follows. For the conjugated diene rubber, gel permeation chromatography measurement is performed using a differential refractive index detector (RI detector) and a viscosity detector as detectors. Among the peaks of the chromatogram by the differential refractive index detector, the weight average molecular weight determined using the high molecular weight side portion having an area of 10% of the total peak area is defined as Mw 10% And among the peaks of the chromatogram by the viscosity detector, the weight average intrinsic viscosity determined using the high molecular weight side portion having an area of 10% of the total peak area is defined as IVw 10%Let's assume that the unit of weight-average intrinsic viscosity is dL / g.

[0037] Below, in equation (1) Mw 10% and IVw 10% I will explain this in more detail.

[0038] As described above, gel permeation chromatography (GPC) measurements will be performed on conjugated diene rubbers using a differential refractive index detector and a viscosity detector. The specific method for GPC measurement is as follows.

[0039] 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" from Tosoh Corporation) are linked together and used. The sample to be measured is dissolved in toluene to a concentration of 1 mg / mL to prepare the measurement solution. 100 μL of the measurement solution is injected into the GPC analyzer and measured under the conditions of oven temperature 40°C and toluene flow rate 1 mL / min.

[0040] The weight-average molecular weight is determined using the high molecular weight side (shorter elution time) portion of the peak (peak originating from conjugated diene rubber) of the chromatogram obtained by a differential refractive index detector (horizontal axis: elution time, vertical axis: signal intensity), which accounts for 10% of the total peak area. The obtained weight-average molecular weight is then expressed as Mw 10% Let's assume that.

[0041] Furthermore, the weight-average intrinsic viscosity is determined using the portion of the chromatogram obtained from the viscosity detector (horizontal axis: elution time, vertical axis: signal intensity) that represents 10% of the total area of ​​the peaks (peaks originating from conjugated diene rubbers), specifically the high molecular weight side (those with shorter elution times). The obtained weight-average intrinsic viscosity is then expressed as IVw. 10% Let's assume that. Weight-average intrinsic viscosity is defined as (Σ(ηi×Mi×Ni)) / (Σ(Mi×Ni)) where the molecular weight Mi is equal to the number of molecules Ni and the intrinsic viscosity is ηi.

[0042] Figure 1 shows an example of a GPC chromatogram (horizontal axis: elution time, vertical axis: signal intensity). Using P1, which is the high molecular weight side (shorter elution time) portion that accounts for 10% of the area of ​​the entire peak P0, Mw 10% and IVw 10% We seek.

[0043] Methods for ensuring that the conjugated diene rubber satisfies formula (1) include, for example, changing the type and amount of specific modifier and the type and amount of specific branching agent in the manufacturing method of the present invention described later.

[0044] Mw 10% For reasons that the effects of the present invention are superior, the value is preferably 100,000 to 10,000,000, and more preferably 1,000,000 to 5,000,000.

[0045] IVw 10% For reasons that the effects of the present invention are superior, the value is preferably 2 to 8, and more preferably 4 to 6.

[0046] [Formula (2)] The specific conjugated diene rubber is preferably one that satisfies the following formula (2) for the reason that the effects of the present invention are superior.

[0047] St + Vn ≤ 50 (2)

[0048] In formula (2), St represents the proportion (mass%) of repeating units derived from styrene to the total specific conjugated diene rubber (hereinafter also referred to as "styrene amount"), and Vn represents the proportion (mass%) of repeating units of a 1,2-vinyl structure derived from a conjugated diene (e.g., butadiene) to the total specific conjugated diene rubber (hereinafter also referred to as "vinyl amount").

[0049] St+Vn is preferably 10 to 45, and more preferably 25 to 45, for better effects of the present invention.

[0050] St is preferably 5 to 40, more preferably 10 to 35, and even more preferably 15 to 30, for better effects of the present invention.

[0051] Vn is preferably 5 to 30, and more preferably 10 to 20, for better effects of the present invention.

[0052] [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 the reasons that the effects of the present invention are superior. Furthermore, the method for measuring the weight-average molecular weight (Mw) of specific conjugated diene rubbers is the same as described above, except that the entire peak is used. 10% It is the same as this.

[0053] [Glass transition temperature] The glass transition temperature (Tg) of the specific conjugated diene rubber is not particularly limited, but it is preferably -100°C to -30°C, and more preferably -80°C to -45°C, for better performance 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 calculated using the midpoint method after measuring it with a differential scanning calorimeter (DSC) at a heating rate of 10°C / min.

[0054] [Preferred Embodiment 1] The specific conjugated diene rubber is preferably having a star-shaped structure with three or more branches, more preferably having a star-shaped structure with three or more branches with a specific modifying group as a branching point, and even more preferably being a conjugated diene rubber represented by the following formula (A).

[0055] [ka]

[0056] In formula (A), X represents an n-valent group (specifically modified group) containing a nitrogen atom, a silicon atom, and an adjacent oxygen atom, P represents a conjugated diene polymer chain, and n represents an integer of 3 or more.

[0057] As described above, X represents an n-valent group (specifically modified group) containing a nitrogen atom, a silicon atom, and an adjacent oxygen atom. For reasons that the effects of the present invention are superior, X preferably contains a silicon atom and an adjacent oxygen atom as an alkoxysilyl group. For reasons that the effects of the present invention are superior, it is preferable that X contains a nitrogen atom as an amino group.

[0058] As mentioned above, P represents a conjugated diene polymer chain. Multiple Ps may be the same or different. The definition, specific examples, and preferred embodiments of conjugated diene polymer chains are the same as those for the specific conjugated diene rubber skeleton described above.

[0059] As described above, n represents an integer of 3 or greater. There is no particular upper limit to n, but it is preferable that it be 30 or less for the reasons that the effects of the present invention are superior.

[0060] [Preferred Embodiment 2] When a specific conjugated diene rubber has a star-shaped structure with three or more branches, it is preferable that at least one branched chain (conjugated diene polymer chain) of the star-shaped structure has a portion derived from a specific branching agent described later, and that this portion has a further main chain branching structure, for reasons that the effects of the present invention are superior. A main chain branched structure refers to a structure in which a branched chain (a conjugated diene polymer chain) forms branching points at a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and further polymer chains (for example, another conjugated diene polymer chain) extend from these branching points.

[0061] [Content] The content of the specific conjugated diene rubber in 100 parts by mass of the conjugated diene rubber is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, and particularly preferably 30 parts by mass or more, for the reasons that the effects of the present invention are superior. There is no particular upper limit, but for the reasons that the effects of the present invention are superior, it is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less.

[0062] [Average Tg] The glass transition temperature (hereinafter also referred to as "average Tg") of the entire conjugated diene rubber is preferably -30°C or lower, more preferably -40°C or lower, and even more preferably -50°C or lower, for the reasons that the effects of the present invention are superior. Furthermore, the above average Tg is preferably -100°C or higher, more preferably -80°C or higher, even more preferably -65°C or higher, and particularly preferably -63°C or higher, for the reasons that the effects of the present invention are superior. The above average Tg is the sum of the glass transition temperatures (Tg) of each component of the conjugated diene rubber multiplied by the mass fraction of each component (weighted average of glass transition temperatures). The method for measuring Tg is as described above.

[0063] [Molecular weight] The preferred embodiment of the weight-average molecular weight (Mw) of the conjugated diene rubber is the same as that of the specific conjugated diene rubber described above.

[0064] [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 above silica may be used alone or in combination of two or more types.

[0065] [CTAB] The specific surface area of ​​silica adsorbing cetyltrimethylammonium bromide (CTAB) (hereinafter, "CTAB adsorption specific surface area" will also be simply referred to as "CTAB") is not particularly limited, but for reasons of superior effectiveness in the present invention, 70 to 300 m² is preferred. 2 It is preferable that the amount be / g, and 110-250m 2 It is more preferable that it be / g. Here, the CTAB adsorption specific surface area is the value measured in accordance with JIS K6430:2008 Annex G.

[0066] [Content] In the composition of the present invention, the silica content is 60 to 120 parts by mass per 100 parts by mass of the rubber component described above. The above content is preferably 70 to 100 parts by mass for better effects of the present invention.

[0067] [Preferred embodiment] The composition of the present invention has a CTAB ratio of 135m relative to the total silica, for reasons that the effects of the present invention are superior. 2 The proportion of silica (hereinafter also referred to as "specific silica") of less than or equal to / g is preferably 80% by mass or less, more preferably 50% by mass or less, and even more preferably 30% by mass or less. The lower limit is not particularly limited and is 0% by mass. CTAB of specific silica is used in 50-130 m for reasons that it provides superior effects in this invention. 2 It is preferable that the value be / g, and 70-120m 2 It is more preferable that it be / g.

[0068] [3] resin The composition of the present invention contains a resin (particularly a thermoplastic resin).

[0069] [Specific example] Examples of resins include coumarone resins (e.g., coumarone resin, coumarone-indene resin, coumarone-indene-styrene resin), phenolic resins (e.g., phenolic 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 esters, hydrogenated rosin derivatives), and terpene resins (e.g., terpene resin, modified terpene). Examples include resins (aromatically modified terpene resins, etc.), terpene phenol resins, hydrogenated terpene resins, α-pinene resins, β-pinene resins, limonene resins, hydrogenated limonene resins, dipentene resins, terpene styrene resins), styrene resins, petroleum resins (for example, C5 resins, C5 / C9 resins, C9 resins, DCPD (dicyclopentadiene) resins, DCPD / C9 resins, hydrogenated C5 / C9 resins, hydrogenated C9 resins, hydrogenated DCPD resins, hydrogenated DCPD / C9 resins), and aliphatic saturated hydrocarbon resins.

[0070] [Preferred embodiment] The above resin preferably contains at least one selected from the group consisting of terpene resins, C5 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, for the reason that the effects of the present invention are superior, and more preferably contains at least one selected from the group consisting of terpene resins, C5 resins, C5 / C9 resins, and C9 resins. Hereinafter, a resin containing 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 will also be referred to as a "specific resin".

[0071] [Content] In the composition of the present invention, the content of the resin (particularly the specific resin) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and particularly preferably 30 parts by mass or more, per 100 parts by mass of the conjugated diene rubber described above, for the reason that the effects of the present invention are superior. While there is no particular upper limit to the content of the above resin, for reasons that the effects of the present invention are superior, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the above-mentioned conjugated diene rubber.

[0072] [4] Plasticizing oil The composition of the present invention contains a plasticizing oil (hereinafter also simply referred to as "oil").

[0073] [Specific example] There are no particular restrictions on the type of oil used; specific examples include mineral oil and vegetable oil. Specific examples of mineral oils include paraffinic, naphthenic, and aromatic oils. Specific examples of vegetable oils include soybean oil, rapeseed oil, coconut oil, and linseed oil.

[0074] [Content] In the composition of the present invention, the oil content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the conjugated diene rubber described above, for the reason that the effects of the present invention are superior. While there is no particular upper limit to the amount of oil contained above, for reasons that the effects of the present invention are superior, it is preferable that the amount be 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the conjugated diene rubber described above.

[0075] In the composition of the present invention, the ratio (mass ratio) of the content of the above-mentioned resin (particularly a specific resin) to the content of the oil is preferably 2.0 or higher, more preferably 2.6 or higher, even more preferably 3.5 or higher, particularly preferably 4.0 or higher, and most preferably 5.0 or higher, for the reasons that the effects of the present invention are superior. There is no particular upper limit, but for the reasons that the effects of the present invention are superior, it is preferably 10.0 or lower. Hereafter, the ratio (mass ratio) of the content of a specific resin to the content of oil will also be referred to as "specific resin / oil".

[0076] [5] Silane coupling agents The composition of the present invention contains a silane coupling agent. 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. Silane coupling agents may be used individually or in combination of two or more types.

[0077] [Hydrolyzable group] The above hydrolyzable group is not particularly limited, but examples include alkoxy groups, phenoxy groups, carboxyl groups, and alkenyloxy groups. Among these, an alkoxy group is preferred because it provides superior effects of the present invention. 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, for superior effects of the present invention. Examples of alkoxy groups with 1 to 4 carbon atoms include methoxy groups, ethoxy groups, and propoxy groups.

[0078] [Organic functional group] The above organic functional groups are not particularly limited, but are preferably groups that can form chemical bonds with organic compounds. Examples include epoxy groups, vinyl groups, acryloyl groups, methacryloyl groups, amino groups, sulfide groups, mercapto groups, and blocked mercapto groups (protected mercapto groups) (e.g., octanoylthio groups). Among these, sulfide groups (especially disulfide groups and tetrasulfide groups), mercapto groups, and blocked mercapto groups are preferred because they provide superior effects for the present invention.

[0079] [Specific example] Specific examples of silane coupling agents include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazoletetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, and 3-octanoylthio-1-propyltriethoxysilane. One of these may be used alone, or two or more may be used in combination.

[0080] [Preferred embodiment] For reasons that the effects of the present invention are superior, the silane coupling agent is preferably a silane coupling agent having a protected mercapto group (hereinafter also referred to as "specific silane coupling agent"). A specific example of a particular silane coupling agent is the aforementioned 3-octanoylthio-1-propyltriethoxysilane.

[0081] [Content] In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but for reasons that the effects of the present invention are superior, it is preferable that the content is 2 to 20 parts by mass per 100 parts by mass of the conjugated diene rubber described above.

[0082] Furthermore, in the composition of the present invention, the content of the silane coupling agent is preferably 1 to 20% by mass, and more preferably 5 to 15% by mass, relative to the silica content, for the reason that the effects of the present invention are superior. [6] Optional component The composition of the present invention may optionally contain components other than those described above (optional components). Examples of such components include fillers other than silica (preferably carbon black), thermally expandable microcapsules, zinc oxide, stearic acid, antioxidants, waxes, processing aids, liquid polymers, vulcanizing agents (e.g., sulfur), vulcanization accelerators, vulcanization activators, and various other additives commonly used in rubber compositions.

[0083] [Carbon Black] The composition of the present invention preferably contains carbon black for better effects of the present invention. The carbon black may be one type of carbon black used alone, or two or more types of carbon black may be used in combination. The carbon black mentioned above 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.

[0084] [N2SA] The nitrogen adsorption specific surface area (N2SA) of the carbon black described above is not particularly limited, but for reasons that the effects of the present invention are superior, it is 50 to 200 m². 2 It is preferable that the value be / g, and 70-150m 2 It is more preferable that the value be / g, and 75-110m 2 It is even more preferable that the value be / g, and 80-100m 2 It is particularly preferable that the value be / g. Here, the nitrogen adsorption specific surface area (N2SA) is the value obtained by measuring the amount of nitrogen adsorbed onto the carbon black surface according to JIS K6217-2:2001 "Part 2: Method for determining specific surface area - Nitrogen adsorption method - Single point method".

[0085] [Content] In the composition of the present invention, the carbon black content is not particularly limited, but for reasons that the effects of the present invention are superior, it is preferably 1 to 100 parts by mass, more preferably 2 to 30 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the conjugated diene rubber described above.

[0086] [7] Parameter P The composition of the present invention has a parameter P (hereinafter also referred to as "P value") of 1.6 or higher. Furthermore, methods for achieving a P-value of 1.6 or higher include, for example, selecting a suitable embodiment for each of the components mentioned above.

[0087]

number

[0088] Here, Pol.Tg represents the glass transition temperature [°C] of the conjugated diene rubber described above, tanδ(Pol.Tg+70°C) represents the loss tangent of the tire rubber composition at a temperature of Pol.Tg+70°C, tanδ(Pol.Tg+130°C) represents the loss tangent of the tire rubber composition at a temperature of Pol.Tg+130°C, and E′(Pol.Tg+70°C) represents the storage modulus [MPa] of the tire rubber composition at a temperature of Pol.Tg+70°C.

[0089] Pol.Tg is the glass transition temperature of the entire conjugated diene rubber as described above, and is the same as the average Tg mentioned above.

[0090] The loss tangent and storage modulus of the tire rubber composition are values ​​obtained after vulcanization. The vulcanization conditions are 160°C for 20 minutes.

[0091] The loss tangent and storage modulus are measured as follows: A vulcanized rubber sheet is prepared using the vulcanization conditions described above. The obtained vulcanized rubber sheet was measured using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K6394:2007, under the conditions of a tensile deformation strain of 10% ± 0.1%, a frequency of 20 Hz, and temperatures of Pol.Tg + 70°C and Pol.Tg + 130°C. The loss tangent was then determined from the storage modulus and loss modulus.

[0092] [tanδ(Pol.Tg+70℃)-tanδ(Pol.Tg+130℃)] The ratio of tanδ(Pol.Tg+70℃)-tanδ(Pol.Tg+130℃) is preferably 0.05 or higher, more preferably 0.10 or higher, and even more preferably 0.15 or higher, for better effects of the present invention. There is no particular upper limit, but it is preferably 0.50 or lower, and more preferably 0.30 or lower, for better effects of the present invention.

[0093] [E'(Pol.Tg+70℃)] E'(Pol.Tg+70℃) is preferably 5 MPa or higher, more preferably 10 MPa or higher, and even more preferably 15 MPa or higher, for better effects of the present invention. There is no particular upper limit, but it is preferably 100 MPa or lower, more preferably 70 MPa or lower, even more preferably 50 MPa or lower, and particularly preferably 30 MPa or lower.

[0094] [P-value] As mentioned above, the p-value is 1.6 or higher. The P-value is preferably 1.8 or higher, more preferably 2.0 or higher, and even more preferably 2.2 or higher, for the sake of superior effects of the present invention. There is no particular upper limit, but for the sake of superior effects of the present invention, it is preferably 10.0 or lower, more preferably 8.0 or lower, and even more preferably 5.0 or lower.

[0095] [8] Method for preparing a rubber composition for tires The method for producing the composition of the present invention is not particularly limited, and specific examples include, for example, a method of kneading each of the above-mentioned components using known methods and equipment (e.g., Banbury mixer, kneader, roll, etc.). If the composition of the present invention contains sulfur or a vulcanization accelerator, it is preferable to first mix the components other than sulfur and the vulcanization accelerator at a high temperature (preferably 100 to 160°C), cool them, and then mix in the sulfur or vulcanization accelerator. Furthermore, the compositions 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 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, and other gases.

[0097] Figure 2 shows a schematic partial cross-sectional view of a tire representing an 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 Figure 2.

[0098] In Figure 2, reference numeral 1 represents the bead portion, reference numeral 2 represents the sidewall portion, and reference numeral 3 represents the tire tread portion. Furthermore, a carcass layer 4 with embedded fiber cords is installed between the pair of left and right bead sections 1, 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. Furthermore, in the tire tread section 3, a belt layer 7 is arranged around the entire circumference of the tire, on the outside of the carcass layer 4. Furthermore, a rim cushion 8 is positioned in the bead portion 1 where it contacts the rim. Furthermore, at least one of reference numerals 2-3, 5-6, and 8 (preferably reference numeral 3) is formed by the composition of the present invention as described above.

[0099] The tire of the present invention can be manufactured, for example, by conventionally known methods. In addition to ordinary air or air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used as the gas to fill the tire. [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 specific conjugated diene rubbers] The following specific conjugated diene rubbers 1 and 2 were synthesized.

[0102] [Specific conjugated diene rubber 1]

[0103] <Polymerization process> In an autoclave equipped with a stirrer, under a nitrogen atmosphere, cyclohexane was charged at a rate of 1000 g / h, 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. Then, n-butyllithium was continuously added at a rate of 1.43 mmol / h, and polymerization was started at 70°C. Once polymerization had stabilized sufficiently, 1-(trimethoxysilyl)-4-vinylbenzene (branching agent) was added at a rate of 0.02 g / h, and the reaction was carried out with stirring. The branching agent is the specific branching agent mentioned above.

[0104] <Modification process> To the solution that flowed out of the reactor outlet, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (denaturant) was added at a rate of 0.08 g / h, and the mixture was stirred to allow the reaction to proceed.

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

[0106] To the obtained solution, 1.14 parts by mass of Irganox 1520L (manufactured by BASF) was added as an antioxidant per 100 parts by mass of conjugated diene rubber. The solvent was then removed by steam stripping, and the solution was vacuum-dried at 60°C for 24 hours to obtain solid conjugated diene rubber. The obtained conjugated diene rubber is also referred to as specific conjugated diene rubber 1.

[0107] Specific conjugated diene rubber 1 is a reaction product of a conjugated diene polymer, which is a copolymer of butadiene, styrene, and a branching agent, and a modifying agent, and is a conjugated diene rubber having a modifying group (specific modifying group) containing a nitrogen atom, a silicon atom, and an adjacent oxygen atom, derived from the modifying agent. The specific conjugated diene rubber 1 has a star-shaped structure with three or more branches, with a modifying group as the branching point. The branched chains bonded to the modifying group have a portion derived from a branching agent, and the portion derived from the branching agent has a further main chain branching structure (conjugated diene polymer chain).

[0108] [Specific conjugated diene rubber 2] Except for changing the amounts of each component used as shown in Table 1, a solid conjugated diene rubber was obtained following the same procedure as for specific conjugated diene rubber 1. The obtained conjugated diene rubber is also called specific conjugated diene rubber 2.

[0109] Specific conjugated diene rubber 2 is a reaction product of a conjugated diene polymer, which is a copolymer of butadiene, styrene, and a branching agent, and a modifying agent, and is a conjugated diene rubber having a modifying group (specific modifying group) containing nitrogen atoms, silicon atoms, and adjacent oxygen atoms derived from the modifying agent. The specific conjugated diene rubber 2 has a star-shaped structure with three or more branches, with a modifying group as the branching point. The branched chains bonded to the modifying group have a portion derived from a branching agent, and the portion derived from the branching agent has a further main chain branching structure (conjugated diene polymer chain).

[0110] [Table 1]

[0111] [Weight-average molecular weight, weight-average intrinsic viscosity, styrene content, vinyl content, glass transition temperature] As described above, for the specific conjugated diene rubbers 1 and 2 synthesized, Mw, Mw 10% , IVw, IVw 10% Table 2 shows the St, Vn, and glass transition temperature (Tg). Similarly, Table 2 also shows the values ​​for NS612, NS616, and E581, which will be discussed later. Note that in Table 2, the "right-hand side" of equation (1) is "3.1 × 10 -6 ×Mw 10% This represents the value "-2.77". Furthermore, in Table 2, "Applicable or not applicable" in formula (1) indicates whether or not formula (1) is applicable. Specifically, "A" indicates that formula (1) is satisfied, and "B" indicates that formula (1) is not satisfied. Furthermore, in Table 2, "St+Vn" in equation (2) represents the St+Vn mentioned above.

[0112] [Table 2]

[0113] As shown in Table 2, both Specified Conjugated Diene Rubbers 1 and 2 are conjugated diene rubbers that satisfy formula (1), and therefore correspond to the Specified Conjugated Diene Rubbers described above. Furthermore, both Specified Conjugated Diene Rubbers 1 and 2 correspond to aromatic vinyl-conjugated diene copolymer rubbers. In other words, both Specified Conjugated Diene Rubbers 1 and 2 are aromatic vinyl-conjugated diene copolymer rubbers that satisfy formula (1). On the other hand, as shown in Table 2, NS612, NS616, and E581 do not satisfy formula (1) and therefore do not fall under the category of the specified conjugated diene rubbers mentioned above.

[0114] [Preparation of rubber compositions for tires] Each component in Tables 3-5 below was mixed in the composition (parts by mass) shown in the same table. Specifically, first, the components other than sulfur and vulcanization accelerator listed in Tables 3-5 were mixed in a 1.8 L sealed mixer at a temperature of 160°C or lower for 5 minutes, and the masterbatch was released. Then, sulfur and vulcanization accelerator were added to the masterbatch and mixed using an open roll at a temperature of 100°C or lower to produce each tire rubber composition.

[0115] [evaluation] The following evaluations were performed on each of the obtained tire rubber compositions.

[0116] [Rolling performance] Using a rubber composition for tires, test tires were fabricated in tire size 245 / 40R19. The test tire was mounted on a wheel with a rim size of 18 x 7.5J, the air pressure was set to 210 kPa, and the rolling resistance was measured when the tire was pressed against the drum using an indoor drum testing machine (drum diameter: 1707 mm) with a load equivalent to 85% of the maximum load at that air pressure as described in the JATMA Yearbook 2009 edition, and the machine was run at a speed of 80 km / h (hour). The reciprocal of the measured value was then indexed, with Example 1 set to 100. The results are shown in Tables 3-5. A higher index indicates lower rolling resistance and superior rolling performance. In practical terms, an index of 90 or higher is preferable.

[0117] [Wet performance] Using a rubber composition for tires, test tires were fabricated in tire size 245 / 40R19. Four test tires were mounted on a passenger car with a 2300cc engine, and the braking distance from an initial speed of 100 km / h (in hours) was measured on a water-sprayed asphalt surface. The reciprocal of the distance was then indexed, with Example 1 set to 100. The results are shown in Tables 3-5. A higher index indicates better wet performance. In practical terms, an index of 90 or higher is preferable.

[0118] [Extrusion processability] The Mooney viscosity of the tire rubber composition was measured according to JIS K6300-1:2013, using an L-shaped rotor, with a preheating time of 1 minute, rotor rotation time of 4 minutes, and a test temperature of 100°C. The viscosity of Example 1 was then indexed with a baseline of 100. The results are shown in Tables 3-5. A smaller index indicates lower viscosity and better extrusion processability. In practical terms, an index of 110 or less is preferable.

[0119] [Table 3]

[0120] [Table 4]

[0121] [Table 5]

[0122] The details of each component in Tables 3-5 are as follows. • Specific conjugated diene rubber 1-2: Specific conjugated diene rubber 1-2 synthesized as described above. • NS612: NS612 manufactured by Nippon Zeon Co., Ltd. (solution polymerized SBR, aromatic vinyl content (styrene content): 15% by mass, Tg: -60℃) (does not satisfy formula (1) and therefore does not fall under the category of the specified conjugated diene rubber mentioned above) • NS616: NS616 manufactured by Nippon Zeon Co., Ltd. (end-modified solution polymerized SBR, aromatic vinyl content (styrene content): 22% by mass, Tg: -23℃) (does not satisfy formula (1) and therefore does not fall under the category of the specified conjugated diene rubber mentioned above) • E581: E581 manufactured by Asahi Kasei Corporation (end-modified solution polymerized SBR with hydroxyl groups at the ends, Tg: -22℃) (Does not satisfy formula (1) and therefore does not fall under the category of the specified conjugated diene rubber mentioned above) • BR1220: Nipol BR1220 (butadiene rubber, Tg: -105℃) manufactured by Nippon Zeon Co., Ltd. • 9100GR: Evonik ULTRASIL 9100GR (Silica, CTAB: 200m) 2 / g) • 115GR: Solvay's Zeosil 115GR (silica, CTAB: 105m) 2 / g) • N339: Cabot Japan Co., Ltd. Show Black N339 (carbon black, nitrogen adsorption specific surface area: 88 m²) 2 / g) • Resin A: YS Resin TO125 (aromatic modified terpene resin) manufactured by Yasuhara Chemical Co., Ltd. • Resin B: HC-3100 (C5 / C9 resin) manufactured by Guangzhou Ecopower New Material Co., Ltd. • Resin C: HT100 (Hydrogenated DCPD resin) manufactured by HANWHA SOLUTIONS CORPORATION • Silane coupling agent A: 3-octanoylthiopropyltriethoxysilane (the compound listed below) (corresponds to the specified silane coupling agent mentioned above)

[0123] [ka] • Silane coupling agent B: Si69 manufactured by Evonik (does not fall under the category of the specified silane coupling agent mentioned above) • 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: Finely powdered sulfur containing Kinka oil, manufactured by Tsurumi Chemical Industry Co., Ltd. • Vulcanization accelerator (CZ): Noxellar CZ-G (CZ), manufactured by Ouchi Shinko Chemical Industry Co., Ltd. • Vulcanization accelerator (DPG): Sumitomo Chemical Co., Ltd.'s Soccinol DG (DPG)

[0124] In addition, the terms "Pol.Tg[℃]", "tanδ(Pol.Tg+70℃)", "tanδ(Pol.Tg+130℃)", "E′(Pol.Tg+70℃)[MP]" and "P-value" in Tables 3-5 are as described above.

[0125] As can be seen from Tables 3 to 5, Examples 1 to 9, which contain at least two types of aromatic vinyl-conjugated diene copolymer rubber, have an IVw of at least one of the aromatic vinyl-conjugated diene copolymer rubbers of less than 2.5 dL / g, contain a specific amount of silica, resin, plasticizing oil, and silane coupling agent, and have a P value of 1.6 or higher, showed excellent rolling performance, wet performance, and extrudeability. Among these, Examples 1 and 3 to 9, which have a P value of 1.8 or higher, showed even better rolling performance. Among these, Examples 1, 3, 5 to 6, and 8 to 9, which have a P value of 2.2 or higher, showed even better rolling performance. Furthermore, a comparison between Example 1 and Example 4 (a comparison of embodiments where only the proportion of the two types of silica differed) showed that Example 4, in which the proportion of specific silica to the total silica was 80% by mass or less, exhibited superior wet performance and extrusion processability. Furthermore, a comparison of Examples 2-4 (comparison of embodiments differing only in the type of resin) showed that Example 4 or Example 3, in which the resin is a terpene-based resin or a hydrogenated DCPD-based resin, exhibited superior rolling and wet performance. In particular, Example 4, in which the resin is a terpene-based resin, showed superior extrusion processability. Furthermore, a comparison of Examples 4, 5, and 7 (a comparison of embodiments that differ only in the type of conjugated diene rubber) showed that Examples 4 and 5, which contained 20 parts by mass or more of aromatic vinyl-conjugated diene copolymer rubber satisfying formula (1) along with 100 parts by mass of conjugated diene rubber, exhibited superior wet performance and extrudeability. In particular, Example 4, which contained 20 parts by mass or more of aromatic vinyl-conjugated diene copolymer rubber with a vinyl content of 45% by mass or less along with 100 parts by mass of conjugated diene rubber, exhibited superior wet performance. Furthermore, a comparison between Example 4 and Example 6 (a comparison of embodiments that differ only in resin content) showed that Example 4, in which the specific resin / oil ratio was 2.6 or higher, exhibited superior wet performance and extruderability. Furthermore, a comparison between Example 4 and Example 8 (a comparison of embodiments where only the type of silane coupling agent differed) showed that Example 8, in which the silane coupling agent was a specific silane coupling agent, exhibited superior rolling performance and wet performance.

[0126] On the other hand, Comparative Example 1, which contained only one type of aromatic vinyl-conjugated diene copolymer rubber, and Comparative Example 4, which contained two types of aromatic vinyl-conjugated diene copolymer rubber, both of which had an IVw of 2.5 dL / g or more, exhibited insufficient extrusion processability. Furthermore, Comparative Examples 2-3 and 5-6, which had a P value of less than 1.6, exhibited insufficient rolling performance, wet performance, and extrusion processability in at least one of these areas. [Explanation of Symbols]

[0127] 1. Bead section 2 Sidewall section 3. Tire tread section 4. Carcass layer 5 Bead core 6. Bead Filler 7 Belt layer 8 Rim Cushion

Claims

1. It contains 100 parts by mass of conjugated diene rubber containing at least two types of aromatic vinyl-conjugated diene copolymer rubber, 60 to 120 parts by mass of silica, a resin, a plasticizing oil, and a silane coupling agent. The weight-average intrinsic viscosity of at least one of the aromatic vinyl-conjugated diene copolymer rubbers is less than 2.5 dL / g. A rubber composition for tires in which the following parameter P is 1.6 or higher. However, the weight-average intrinsic viscosity is determined by performing gel permeation chromatography on aromatic vinyl-conjugated diene copolymer rubber using a viscosity detector, and using the entire peak of the chromatogram. [Math 1] Here, Pol. Tg represents the glass transition temperature [°C] of the conjugated diene rubber, tanδ(Pol. Tg + 70°C) represents the loss tangent of the tire rubber composition at a temperature of Pol. Tg + 70°C, tanδ(Pol. Tg + 130°C) represents the loss tangent of the tire rubber composition at a temperature of Pol. Tg + 130°C, and E'(Pol. Tg + 70°C) represents the storage modulus [MPa] of the tire rubber composition at a temperature of Pol. Tg + 70°C.

2. The CTAB relative to the entire silica is 135 m ２ The tire rubber composition according to claim 1, wherein the proportion of silica at or below / g is 80% by mass or less.

3. The tire rubber composition according to claim 1, wherein 100 parts by mass of the conjugated diene rubber comprises 20 parts by mass or more of aromatic vinyl-conjugated diene copolymer rubber in which the proportion of repeating units of the 1,2-vinyl structure derived from the conjugated diene is 45% by mass or less.

4. The content of the resin relative to 100 parts by mass of the conjugated diene rubber is 15 parts by mass or more. The 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. The tire rubber composition according to claim 1, wherein the ratio of the resin content to the plasticizing oil content is 2.6 or more by mass.

5. The tire rubber composition according to claim 1, wherein 100 parts by mass of the conjugated diene rubber comprises 20 parts by mass or more of an aromatic vinyl-conjugated diene copolymer rubber satisfying the following formula (1). [Vw １０％ ≦3.1×10 －６ ×Mw １０％ -2.77 (1) Mw in equation (1) １０％ and IVw １０％ The details are as follows: Gel permeation chromatography measurements will be performed on aromatic vinyl-conjugated diene copolymers 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 peaks obtained by a differential refractive index detector, which accounts for 10% of the total peak area. １０％ Furthermore, the weight-average intrinsic viscosity IVw is determined using the high molecular weight portion of the chromatogram peaks obtained by the viscosity detector, which accounts for 10% of the total peak area. １０％ Let's assume that the unit of weight-average intrinsic viscosity is dL / g.

6. The tire rubber composition according to claim 1, wherein the silane coupling agent is a silane coupling agent having a protective mercapto group.

7. A tire manufactured using the tire rubber composition described in any one of claims 1 to 6.

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