JP2019183101A - Rubber composition for tire, and tire - Google Patents

Abstract

To provide a rubber composition for a tire improving wet grip during high speed traveling, abrasion resistance, operation stability and low fuel consumption at good balance, and suppressing performance deterioration after a long use, and the tire using the rubber composition.SOLUTION: There is related a rubber composition for a tire having content of a component derived from an aromatic vinyl monomer of 3 to 25 mass%, content of a component derived from a butadiene monomer and having a vinyl structure of 0 to 15 mass%, content of a component derived from the butadiene monomer and having a cis structure of 1 to 90 mass%, and content of a component derived from an isoprene monomer and having a cis structure of 1 to 6 mass% in a rubber component of 100 mass%, and physical properties after vulcanization satisfying following formulae (1) and (2). -25°C<Tg<0°C (1) 65<Hs<75 (2).SELECTED DRAWING: None

Description

The present invention relates to a tire rubber composition and a tire.

In recent years, automobile tires are particularly required to have a good balance between low fuel consumption, grip performance, and wear resistance. For example, Patent Document 1 discloses a technique of blending a specific modified diene rubber and a specific silica to meet this requirement.

International Publication No. 2013/125614

In order to improve the grip performance such as wet grip, it is possible to add a large amount of plasticizer such as resin, and in order to improve the wear resistance, it is possible to add a large amount of filler such as silica. In this method, it was difficult to disperse silica, and there was a tendency that the wear resistance was not sufficiently improved.

Further, when high-speed driving is required as in Europe, there is a tendency that it is particularly difficult to achieve both wear resistance and low fuel consumption.

In addition, as the product life of tires increases with improved wear resistance, various performances are required not to deteriorate even after long-term use, but there is still room for improvement with regard to performance deterioration after long-term use. was there.

Also, during long-term use at high speeds, just as with conventional fillers and plasticizers, the amount of wear resistance is higher than that in low to medium speeds. , Wet grip and steering stability tended to be insufficient. Therefore, development of a rubber composition that can withstand long-term use at high speed has been desired.

Also, in order to ensure a good balance of various performances such as low fuel consumption and wet grip, a method of blending a plurality of rubber types having different monomer components and microstructures such as styrene butadiene rubber (SBR) and butadiene rubber (BR). Is widely practiced. However, when a plurality of rubber types are compounded, the performance assumed by the phase separation cannot be expressed, the performance is deteriorated in a specific temperature range, the filler is ubiquitous, and the wear resistance is lowered. There was a case.

Also, in order to improve fuel efficiency, among the monomer components of the rubber component, SBR and styrene units and vinyl units are reduced as the amount of styrene and vinyl units is reduced (about 10% by mass). Application of Hi-Sis BR is also performed. However, with this method, grip performance decreases due to a decrease in the number of styrene units and vinyl units, and further, mechanical strength is insufficient due to a decrease in vinyl units that tend to contribute to crosslinking, and wear resistance tends to decrease. was there.

In order to improve wear resistance and workability, a technology for blending thermoplastic elastomers has also been developed. However, since general thermoplastic elastomers have low hardness at high temperatures, steering stability is improved during high-speed driving. There was a tendency to decrease.

As described above, it has been difficult to improve tire performance such as low fuel consumption in a well-balanced manner while considering performance maintenance during high-speed driving and long-term use.

The present invention solves the above-mentioned problems, improves the wet grip, wear resistance, steering stability and fuel efficiency during high-speed running in a well-balanced manner, and suppresses performance deterioration after long-term use. And it aims at providing the tire using the same.

In the present invention, the content of the component derived from the aromatic vinyl monomer is 3 to 25% by mass in 100% by mass of the rubber component, and the content of the component derived from the butadiene monomer having a vinyl structure is 0 to 15%. 1% to 90% by mass of a component derived from a butadiene monomer and having a cis structure, and 1 to 6% by mass of a component derived from an isoprene monomer and having a cis structure It is related with the rubber composition for tires in which the physical property after vulcanization satisfy | fills following formula (1) and (2).
−25 ° C. <Tg <0 ° C. (1)
Tg: temperature at which tan δ is maximum when viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25% 65 <Hs <75 (2)
Hs: Hardness at 23 ° C. measured according to JIS K6253

The rubber composition has a single peak at a temperature of −80 ° C. or higher when a viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25%. It is preferable.

The viscoelastic spectrum preferably has a single peak at −90 ° C. or higher.

The rubber composition preferably has physical properties after vulcanization that satisfy the following formulas (3) and (4).
tan δ1> 0.80 (3)
tan δ2 <0.15 (4)
tan δ1: tan δ at −5 ° C. when viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%
tan δ2: tan δ at 80 ° C. when measuring viscoelasticity at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%

The rubber component preferably contains a solution-polymerized styrene butadiene rubber having a vinyl structure content of 25% by mass or less in 100% by mass of the component derived from the butadiene monomer.

The weight average molecular weight of the solution polymerized styrene butadiene rubber is preferably 800,000 or more.

The rubber component preferably contains at least one selected from the group consisting of hydrogenated styrene butadiene rubber, styrene thermoplastic elastomer, and olefin-conjugated diene-styrene copolymer.

The rubber composition contains silica, and the content of the silica with respect to 100 parts by mass of the rubber component is preferably 100 to 300 parts by mass.

It is preferable that the rubber component has a single morphology.

The rubber composition contains a resin having a softening point of 25 ° C. or higher, and the content of the resin with respect to 100 parts by mass of the rubber component is preferably 1 to 60 parts by mass.

The resin is preferably at least one selected from the group consisting of a styrene resin, a terpene resin, a C5 resin, a C5 / C9 resin, a DCPD resin, and a rosin resin.

The rubber composition is preferably a cap tread rubber composition.

The present invention also includes a cap tread composed of the rubber composition and a base tread produced using a rubber composition having a styrene butadiene rubber content of 10% by mass or more in 100% by mass of the rubber component. Regarding tires.

According to the present invention, in 100% by mass of the rubber component, the content of the component derived from the aromatic vinyl monomer is 3 to 25% by mass, and the content of the component derived from the butadiene monomer having a vinyl structure is 0. 15% by mass of a component derived from a butadiene monomer and having a cis structure content of 1 to 90% by mass, a component derived from an isoprene monomer and having a cis structure having a content of 1 to 6 Since the rubber composition for tires satisfying the formulas (1) and (2), the physical properties after vulcanization satisfy the following formulas (1) and (2), which balances wet grip, wear resistance, handling stability and low fuel consumption during high-speed driving. While improving well, the performance degradation after a long-term use can be suppressed.

In the rubber composition of the present invention, the content of the component derived from the aromatic vinyl monomer is 3 to 25% by mass in 100% by mass of the rubber component, and the content of the component derived from the butadiene monomer having a vinyl structure Is a component derived from a butadiene monomer and having a cis structure content of 1 to 90% by mass, a component derived from an isoprene monomer and having a cis structure content of 1 The physical properties after vulcanization satisfy the formulas (1) and (2).

Controlling the composition in the rubber component within the above range and satisfying the formulas (1) and (2) after vulcanization, the wet grip and wear resistance during high-speed running, which was difficult with conventional methods Performance, steering stability and fuel efficiency can be improved in a well-balanced manner.

The rubber composition satisfying the formulas (1) and (2) after vulcanization controls the composition in the rubber component within the above range and, if necessary, a chemical such as a filler or a plasticizer. However, by controlling the composition in the rubber component within the above range, the chemical is well dispersed in the rubber composition, and the migration of the chemical to other tire members and the surface is suppressed. . Thereby, the performance degradation after long-term use can be suppressed.

Formula (1) is as follows.
−25 ° C. <Tg <0 ° C. (1)
Tg: Temperature at which tan δ is maximized when measuring viscoelasticity at a frequency of 10 Hz, initial strain of 10%, and dynamic strain amplitude of 0.25% (glass transition temperature)
From the viewpoint of low fuel consumption and the like, a rubber composition using SBR having a styrene amount and a vinyl amount of about 10% by mass has been developed. In such a rubber composition, Tg is less than −25 ° C. When Tg is less than −25 ° C., wet grip and steering stability during high-speed running tend to decrease. In the said rubber composition, since Tg exists in the range of Formula (1), a favorable wet grip and steering stability are securable also at the time of high speed driving | running | working.
In the formula (1), Tg is preferably −25 ° C. <Tg ≦ −5 ° C., more preferably −25 ° C. <Tg ≦ −10 ° C.

Formula (2) is as follows.
65 <Hs <75 (2)
Hs: Hardness at 23 ° C. measured according to JIS K6253 The rubber composition can improve steering stability, fuel efficiency and wear resistance in a well-balanced manner when Hs satisfies the formula (2).
In the formula (2), Hs is preferably 66 or more, preferably 73 or less, more preferably 71 or less.

It is preferable that the rubber composition further satisfies the following formulas (3) and (4) in terms of physical properties after vulcanization.
tan δ1> 0.80 (3)
tan δ2 <0.15 (4)
tan δ1: tan δ at −5 ° C. when viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%
tan δ2: tan δ at 80 ° C. when measuring viscoelasticity at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%

As in equation (3), by setting tan δ1 to a value exceeding 0.80, wet grip during high-speed traveling can be further improved. In Expression (3), the upper limit of tan δ1 is not particularly limited.
The present inventors have newly found that a wet grip is usually evaluated by tan δ at 0 ° C., and that a particularly good wet grip can be obtained by adjusting tan δ at −5 ° C. Is.

As in equation (4), by setting tan δ2 to a value less than 0.15, both low fuel consumption and wet grip can be achieved. In the formula (4), tan δ2 is preferably 0.14 or less, preferably 0.05 or more, more preferably 0.08 or more.
Low fuel consumption is usually evaluated by tan δ at 30 to 70 ° C. By adjusting tan δ at 80 ° C., good fuel consumption can be obtained and wet grip can be improved. The present inventors have newly found out.

The rubber composition has a single peak at a viscosity of −80 ° C. or higher when a viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25%. It is preferable that it has a single peak at −90 ° C. or higher. A single peak means that only one peak is observed in the viscoelastic spectrum. Quantitatively, there is only one interval that decreases after the value of tan δ increases by 0.2 or more. Means that. Thereby, wear resistance, steering stability, low fuel consumption, and performance maintenance characteristics during long-term use can be improved in a well-balanced manner. A single peak indicates that the affinity of each component in the rubber composition is good. Therefore, if it is a single peak, various performances can be satisfactorily exhibited under a wide range of use conditions (speed, temperature, load).

In addition, the rubber composition in which the physical property after vulcanization satisfies the formulas (1) to (4) and a viscoelastic spectrum having a single peak in a predetermined range is obtained includes a component derived from an aromatic vinyl monomer. A component derived from a butadiene monomer, having a vinyl structure, a component derived from a butadiene monomer, having a cis structure, and a component derived from an isoprene monomer In addition to adjusting the content of those having a cis structure to the above-mentioned range, it can be prepared by blending a rubber component, a filler, a plasticizer, etc., which will be described later, if necessary. As the plasticizer, oil, liquid rubber or the like can be used.

The design guidelines for the rubber composition satisfying the above-described conditions are as follows. In addition, these design guidelines are only examples, and the present invention is not limited thereto.
In order to reduce Tg, methods such as reducing the amount of styrene and / or vinyl in the rubber component, reducing the amount of high-Tg resin, and blending a highly polar plasticizer can be mentioned. In order to do this, techniques such as increasing the amount of styrene and / or vinyl in the rubber component, increasing the blending amount of high Tg resin, and the like can be mentioned.
When reducing Hs, techniques such as reducing the blending amount of fillers such as silica and carbon black, increasing the blending amount of plasticizers such as resins and oils, reducing the blending amount of crosslinking agents such as sulfur, etc. When increasing Hs, methods such as increasing the compounding amount of fillers such as silica and carbon black, decreasing the compounding amount of plasticizers such as resin and oil, and increasing the compounding amount of crosslinking agents such as sulfur are listed. It is done.
To reduce tan δ1, adjust the Tg of the rubber composition to a temperature away from −5 ° C., reduce the amount of filler such as silica and carbon black, reduce the amount of plasticizer such as resin and oil, When tan δ1 is increased, the Tg of the rubber composition is adjusted to around −5 ° C., the amount of filler such as silica or carbon black is increased, and a plasticizer such as resin or oil is added. Examples of the method include increasing the amount.
When tan δ2 is reduced, the amount of filler such as silica or carbon black is reduced, the amount of styrene and / or vinyl in the rubber component is reduced, the filler is dispersed well, and the rubber component and the filler are bonded. For example, when tan δ2 is increased, the amount of filler such as silica or carbon black is increased, the amount of styrene and / or vinyl in the rubber component is increased, Examples thereof include a method of deteriorating filler dispersion.
When making the peak of a viscoelastic spectrum single, the method of mix | blending a highly compatible rubber component and resin and making it the state close | similar to a single morphology is mentioned.
In the case of moving the peak position to the high temperature side, a technique such as increasing the blending amount of a high Tg chemical (rubber component, resin, etc.) can be mentioned.

The component derived from an aromatic vinyl monomer is a unit based on an aromatic vinyl compound in a (co) polymer obtained by (co) polymerizing an aromatic vinyl compound. As a rubber component having a component derived from an aromatic vinyl monomer (aromatic vinyl unit), styrene butadiene rubber (SBR) or the like can be used.

A component derived from a butadiene monomer is a unit based on 1,3-butadiene in a (co) polymer obtained by (co) polymerizing 1,3-butadiene, and hydrogenated after (co) polymerization. Included units are also included. As a rubber component having a component derived from a butadiene monomer (butadiene unit), SBR, butadiene rubber (BR), or the like can be used.

The component derived from the isoprene monomer is a unit based on isoprene in a (co) polymer obtained by (co) polymerizing isoprene. As a rubber component having a component derived from an isoprene monomer (isoprene unit), natural rubber (NR), isoprene rubber (IR), or the like can be used.

In 100% by mass of the rubber component, the content of the component derived from the aromatic vinyl monomer (aromatic vinyl unit) may be 3 to 25% by mass, from the viewpoint of low fuel consumption, wear resistance and wet grip. , Preferably 5 to 25% by mass, more preferably 8 to 25% by mass.
Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. These may be used individually by 1 type and may use 2 or more types together. Of these, styrene is preferable.

In 100% by mass of the rubber component, the content of a component derived from a butadiene monomer and having a vinyl structure (vinyl butadiene unit) may be 0 to 15% by mass, but it is resistant to abrasion and mechanical strength. In view of the above, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, and from the viewpoint of wear resistance and performance maintaining characteristics during long-term use, preferably 12% by mass or less, more preferably It is 10 mass% or less, More preferably, it is 8 mass% or less.

In 100% by mass of the rubber component, the content of a component derived from a butadiene monomer and having a cis structure (cis-butadiene unit) may be 1 to 90% by mass, preferably 5% by mass or more, More preferably, it is 10 mass% or more, and preferably 80 mass% or less. Within the above range, good rubber elasticity can be obtained, and wear resistance, mechanical strength, and performance maintaining characteristics during long-term use can be improved in a well-balanced manner.

In 100% by mass of the rubber component, the content of a component derived from an isoprene monomer and having a cis structure (cis isoprene unit) may be 1 to 6% by mass, preferably 2 to 6% by mass. That's it. Within the above range, wear resistance, mechanical strength, and performance maintenance characteristics during long-term use can be improved in a well-balanced manner.
In general, when the amount of vinyl butadiene unit in the rubber component is reduced, the fuel efficiency is improved, but the mechanical strength and the handling stability tend to be lowered. In the present invention, by controlling the cisisoprene within the above range, good mechanical strength and steering stability can be obtained while enjoying the effect of improving the fuel efficiency by reducing the amount of vinyl butadiene units.

The content of the aromatic vinyl unit, vinyl butadiene unit, cis butadiene unit and cis isoprene unit in the rubber component can be calculated by the integration ratio of the peaks belonging to each unit using a nuclear magnetic resonance apparatus (NMR). it can. Moreover, when it is difficult to measure by NMR in the rubber composition after vulcanization, it can be calculated from the peak intensity attributed to each unit using infrared spectroscopy (IR).

In the rubber composition, the rubber component preferably has a single morphology. A single morphology means a state in which a plurality of rubber phases are not observed in a rubber component in a microscope observation such as a transmission electron microscope (TEM). Aggregation of filler, filler and polymer (rubber component) This does not include the heterogeneity of the binder phase with). Conventionally, in order to improve various performances in a well-balanced manner, tire rubber compositions often contain a plurality of rubber components that are incompatible with each other, resulting in a non-uniform morphology in many cases. On the other hand, the rubber composition can easily obtain a single morphology by adjusting the content of the aromatic vinyl unit, the vinyl butadiene unit, the cis butadiene unit, and the cis isoprene unit to the above ranges. By using a single morphology, it is possible to improve the wet grip, wear resistance, steering stability and low fuel consumption during high-speed traveling in a well-balanced manner and the performance maintenance characteristics during long-term use.

The rubber component used in the rubber composition includes a diene rubber or a thermoplastic elastomer that is solid at room temperature (20 ° C.). A liquid rubber that functions as a plasticizer or a resin that does not have rubber elasticity Not included. A rubber component may be used individually by 1 type and may use 2 or more types together.

Examples of diene rubber include SBR, BR, NR, IR, butyl rubber (IIR) and the like, homopolymers of diene monomers, copolymers of diene monomers, diene monomers and other monomers such as aromatic vinyl monomers Copolymers can be used. The amount of other monomers used may be in a range that does not impair rubber elasticity. The main chain and / or terminal of the diene rubber may be modified with a polar group, and may be condensed and / or branched using a catalyst. Moreover, diene rubber may be used individually by 1 type, and may use 2 or more types together.

The rubber composition preferably contains solution-polymerized SBR (S-SBR) as a rubber component. Thereby, workability and wet grip can be improved with good balance.

In S-SBR, in 100% by mass of the component derived from the butadiene monomer, the content of one having a vinyl structure (vinyl butadiene unit) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, More preferably, it is 0.5 mass% or more. If it is in the said range, a crosslinking reaction and reaction with a silane coupling agent can be accelerated | stimulated, and low fuel consumption and abrasion resistance can be improved with good balance. Further, the content of the vinyl butadiene unit is preferably 28% by mass or less, more preferably 27% by mass or less, and further preferably 25% by mass or less. If it is in the said range, the Tg raise of a rubber component will be suppressed and low-temperature performance can be improved. Furthermore, affinity and compatibility with other rubber components are improved, and good fracture resistance is obtained.

In S-SBR, the content of a component having a cis structure (cis butadiene unit) in 100% by mass of the component derived from the butadiene monomer is preferably 20% by mass or more, and preferably 90% by mass or less. . Within the above range, good rubber elasticity can be obtained, and wear resistance and fracture resistance can be improved in a balanced manner.

The amount of styrene in S-SBR (content of styrene units in 100% by mass of S-SBR) is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass, and preferably It is 40 mass% or less, More preferably, it is 30 mass% or less, More preferably, it is 25 mass% or less. Within the above range, wet grip and fuel efficiency can be improved in a well-balanced manner. Furthermore, affinity and compatibility with other rubber components are improved, and good fracture resistance is obtained.

S-SBR preferably has a terminal and / or main chain modified with a polar group that interacts with a filler such as silica. Although it does not specifically limit as a polar group (modification group), An alkoxy silyl group, an amino group, a hydroxyl group, a carboxyl group, an epoxy group etc. are mentioned. These may be one kind or two or more kinds. Of these, an alkoxysilyl group is preferable.

The weight average molecular weight (Mw) of S-SBR is preferably 500,000 or more, more preferably 600,000 or more, still more preferably 700,000 or more, and still more preferably 800,000 or more, from the viewpoints of wear resistance and mechanical strength. More preferably, it is 900,000 or more, and still more preferably 1,000,000 or more. The upper limit is not particularly defined, but is preferably 3 million or less from the viewpoint of workability.

S-SBR may have a block of components derived from isoprene (isoprene block) in the molecular chain. Thereby, low fuel consumption, wear resistance, and steering stability can be improved in a well-balanced manner. The isoprene block is preferably a block of a component derived from cisisoprene (cisisoprene block).

In 100% by mass of the rubber component, the content of S-SBR is preferably 10% by mass or more, more preferably 25% by mass or more, and preferably 99% by mass or less, more preferably 97% by mass or less. . Within the above range, the effects of the present invention tend to be obtained more favorably.
The S-SBR content described here does not include hydrogenated SBR described later.

The rubber composition may contain hydrogenated SBR (hydrogenated SBR) in which a part of the butadiene units in SBR are hydrogenated as a rubber component. Hydrogenated SBR has the effect of improving the affinity with a plasticizer by reducing the amount of double bonds by hydrogenation, and also making the cross-linked structure uniform by reducing the reaction part with the cross-linking agent. As a result, it is possible to further improve the wear resistance and performance maintaining characteristics during long-term use.

The hydrogenation rate of the butadiene unit of the hydrogenated SBR is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less. If it is in the said range, steering stability, mechanical strength, abrasion resistance, and the performance maintenance characteristic at the time of long-term use can be improved more.
The hydrogenation rate is the amount of the unit to which hydrogen is added in 100% by mass of the butadiene unit, and is calculated from the spectrum reduction rate of the unsaturated bond portion of the spectrum obtained by measuring H ¹ -NMR. can do.

There are no particular limitations on the hydrogenation method and reaction conditions, and hydrogenation may be performed using known methods and known conditions. Usually, it is carried out in the presence of a hydrogenation catalyst at 20 to 150 ° C. under hydrogen pressure of 0.1 to 10 MPa. The hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, the reaction time, and the like. As the hydrogenation catalyst, a compound containing any of metals in Group 4 to 11 of the periodic table can be used. For example, a compound containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, and Pt atoms can be used as the hydrogenation catalyst. More specific hydrogenation catalysts include metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, and Re; metals such as Pd, Ni, Pt, Rh, and Ru are carbon, A supported heterogeneous catalyst supported on a carrier such as silica, alumina, diatomaceous earth; a homogeneous Ziegler catalyst in which an organic salt of a metal element such as Ni or Co or an acetylacetone salt and a reducing agent such as organoaluminum is combined; Examples include organometallic compounds or complexes such as Ru and Rh; fullerenes and carbon nanotubes in which hydrogen is occluded.

Of these, metallocene compounds containing any one of Ti, Zr, Hf, Co, and Ni are preferable in that they can be hydrogenated in a homogeneous system in an inert organic solvent. Furthermore, a metallocene compound containing any of Ti, Zr, and Hf is preferable. In particular, a hydrogenation catalyst obtained by reacting a titanocene compound with an alkyl lithium is preferable because it is an inexpensive and industrially useful catalyst. Specific examples include, for example, JP-A-1-275605, JP-A-5-271326, JP-A-5-271325, JP-A-5-222115, JP-A-11-292924, and JP-A-11-292924. JP 2000-37632 A, JP 59-133203 A, JP 63-5401 A, JP 62-218403 A, JP 7-90017 A, JP 43-19960 A, Mention may be made of the hydrogenation catalyst described in JP-B 47-40473. In addition, these hydrogenation catalysts can be used individually by 1 type or in combination of 2 or more types.

In 100% by mass of the component derived from the butadiene monomer before hydrogenation in the hydrogenated SBR, the content of one having a vinyl structure (vinyl butadiene unit) is preferably 0 to 10% by mass, more preferably 0 to 5% by mass. %, More preferably 0 to 3% by mass. If it is in the said range, mechanical strength, abrasion resistance, and the performance maintenance characteristic at the time of long-term use can be improved more.

In 100% by mass of the component derived from the butadiene monomer before hydrogenation in the hydrogenated SBR, the content of those having a cis structure (cis butadiene unit) is preferably 1 to 10% by mass. If it is in the said range, mechanical strength, abrasion resistance, and the performance maintenance characteristic at the time of long-term use can be improved more.

The hydrogenated SBR preferably has a terminal and / or main chain modified with a polar group that interacts with a filler such as silica. Although it does not specifically limit as a polar group (modification group), An alkoxy silyl group, an amino group, a hydroxyl group, a carboxyl group, an epoxy group etc. are mentioned. These may be one kind or two or more kinds. Of these, an alkoxysilyl group is preferable.

When hydrogenated SBR is contained, the content of hydrogenated SBR in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 90% by mass or less. Preferably it is 70 mass% or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
In addition, the above-mentioned S-SBR is not included in the content of hydrogenated SBR described here.

The rubber composition may contain a styrene thermoplastic elastomer (styrene TPE) or an olefin-conjugated diene-styrene copolymer as a rubber component. By blending these components while controlling the constitution of the rubber component within the above range, it is possible to impart appropriate elasticity and hardness to the rubber composition, and to further improve steering stability and wet grip. Furthermore, adhesion between rubber components can be strengthened, and mechanical strength and wear resistance can be further improved. Styrenic TPE and olefin-conjugated diene-styrene copolymer may be used alone, in combination of two or more, or in combination with other rubber components such as diene rubber. Also good.

Styrene-based TPE is a thermoplastic elastomer having a styrene unit, and specific examples thereof include a block copolymer of styrene and butadiene and / or isoprene. A styrene-butadiene-styrene triblock copolymer ( SBS), styrene-butadiene-styrene-butadiene tetrablock copolymer (SBSB), and hydrogenated products thereof are particularly suitable. Although the manufacturing method of styrene-type TPE is not specifically limited, For example, it can manufacture by the method of Unexamined-Japanese-Patent No. 2014-105293.

The olefin-conjugated diene-styrene copolymer is a copolymer obtained by copolymerizing an olefin monomer, a conjugated diene monomer, and a styrene monomer. Although the manufacturing method of an olefin-conjugated diene-styrene copolymer is not specifically limited, For example, it can manufacture by the method of patent 4088258.

Examples of the olefin monomer used in the olefin-conjugated diene-styrene copolymer include ethylene, propylene, 1-butene, 2-butene, isobutene, 1-hexene, 1-octene, 1-heptene, and 1-decene. Examples include olefins. These may be used individually by 1 type and may use 2 or more types together. Of these, ethylene is preferable.

Examples of the conjugated diene monomer used in the olefin-conjugated diene-styrene copolymer include 1,3-butadiene, isoprene, 1,3-pentanediene, 2,3-dimethylbutadiene, 2-phenyl-1,3- Examples include butadiene. These may be used individually by 1 type and may use 2 or more types together. Of these, 1,3-butadiene is preferable.

The amount of styrene in the styrene-based TPE and the olefin-conjugated diene-styrene copolymer is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 65% by mass or less, more preferably 60% by mass. It is as follows. Within the above range, moderate rubber elasticity can be obtained, and affinity with other rubber components can be improved.

In 100 parts by mass of the component derived from the conjugated diene monomer in the styrene-based TPE and the olefin-conjugated diene-styrene copolymer, the content of those having a vinyl structure is preferably 0 to 20% by mass, more preferably 0 to 10%. % By mass. If it is in the said range, mechanical strength, abrasion resistance, and the performance maintenance characteristic at the time of long-term use can be improved more.

When the styrene TPE is contained, the content of the styrene TPE in 100% by mass of the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 80% by mass or less. Preferably it is 50 mass% or less. The same applies to the content of the olefin-conjugated diene-styrene copolymer. Within the above range, the elastic modulus, fuel efficiency, wear resistance and mechanical strength can be obtained in a balanced manner.

The rubber composition preferably contains isoprene-based rubber as a rubber component. Examples of the isoprene-based rubber include NR, IR, modified NR, modified NR, and modified IR. As NR, SIR20, RSS # 3, TSR20, etc., IR, IR2200, etc., those commonly used in the tire industry can be used. Modified NR is deproteinized natural rubber (DPNR), high purity natural rubber (UPNR), etc. Modified NR is epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Modified IR Epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, and the like. These may be used alone or in combination of two or more. Of these, modified NR is preferable, and UPNR is more preferable.

As the UPNR, one produced by the method described in Japanese Patent No. 56509797 can be used. The pH of UPNR is preferably 2-7, more preferably 3-6, and even more preferably 4-6. The phosphorus content of UPNR is preferably 200 ppm or less, more preferably 150 ppm or less. The nitrogen content after UPNR is immersed in acetone at 25 ° C. for 48 hours is preferably 0.15% by mass or less, more preferably 0.1% by mass or less.

When the isoprene-based rubber is contained, the content of the isoprene-based rubber in 100% by mass of the rubber component may be adjusted within a range satisfying the configuration in the rubber component described above, preferably 1% by mass or more, more preferably It is 2 mass% or more, preferably 10 mass% or less, more preferably 5 mass% or less.

The rubber composition may contain BR as a rubber component. The BR is not particularly limited, and those known in the tire field such as BR (high cis BR) having a cis amount of 95% by mass or more and BR containing syndiotactic polybutadiene crystals can be used. Among these, high cis BR can be preferably used. As BR, either non-modified BR or modified BR can be used. As commercially available products, products such as Ube Industries, JSR, Asahi Kasei, and Nippon Zeon can be used. These may be used alone or in combination of two or more.

When BR is contained, the BR content in 100% by mass of the rubber component may be adjusted within a range that satisfies the above-described configuration in the rubber component, but is preferably 1% by mass or more, more preferably 5% by mass or more. Moreover, Preferably it is 20 mass% or less, More preferably, it is 15 mass% or less.

Examples of the filler that can be used in the rubber composition include silica, carbon black, aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, alumina, and clay. These may be used individually by 1 type and may use 2 or more types together. Of these, silica and carbon black are preferable.

When the rubber composition contains silica, wet grip, wear resistance, fuel efficiency, and performance maintaining characteristics during long-term use can be further improved.
Examples of the silica include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid) and the like, but wet process silica is preferred because of the large number of silanol groups. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 150 m ² / g or more, more preferably 170 m ² / g or more, still more preferably 200 m ² / g or more, and preferably 300 m ² / g or less. More preferably, it is 250 m ² / g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The _N 2 SA of silica is a value measured by the BET method in accordance with ASTM D3037-81.

The CTAB (cetyltrimethylammonium bromide) specific surface area of silica is preferably 150 m ² / g or more, more preferably 190 m ² / g or more, still more preferably 200 m ² / g or more, and preferably 300 m ² / g or less. More preferably, it is 250 m ² / g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The CTAB specific surface area of silica is a value measured according to ASTM D3765-92.

Examples of silica that can be used include products such as Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama.

When silica is contained, the content of silica with respect to 100 parts by mass of the rubber component is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, still more preferably 90 parts by mass or more, and particularly preferably 100 parts by mass or more. . Within the above range, wet grip and wear resistance can be further improved. Although an upper limit is not specifically limited, From a viewpoint of workability and rubber elasticity, Preferably it is 300 mass parts or less, More preferably, it is 200 mass parts or less, More preferably, it is 180 mass parts or less.

Silica is preferably used in combination with a silane coupling agent. Thereby, there exists a tendency for the effect of this invention to be acquired more favorably.
The silane coupling agent is not particularly limited. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, Bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis ( 3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilyl ester) 3) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3 -Sulfide systems such as triethoxysilylpropyl methacrylate monosulfide, mercapto systems such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane, vinyl systems such as vinyltriethoxysilane and vinyltrimethoxysilane, 3-amino Amino-based compounds such as propyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; Toro propyltrimethoxysilane, 3-nitro-triethoxysilane and nitro-based, 3-chloropropyl trimethoxy silane, chloro system such as 3-chloropropyl triethoxysilane and the like. These may be used alone or in combination of two or more. Of these, sulfide and mercapto are preferable, and mercapto is more preferable.

（式中、Ｒ^１０１〜Ｒ^１０３は、分岐若しくは非分岐の炭素数１〜１２のアルキル基、分岐若しくは非分岐の炭素数１〜１２のアルコキシ基、又は−Ｏ−（Ｒ^１１１−Ｏ）_ｂ−Ｒ^１１２（ｂ個のＲ^１１１は、分岐若しくは非分岐の炭素数１〜３０の２価の炭化水素基を表す。ｂ個のＲ^１１１はそれぞれ同一でも異なっていてもよい。Ｒ^１１２は、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、炭素数６〜３０のアリール基、又は炭素数７〜３０のアラルキル基を表す。ｂは１〜３０の整数を表す。）で表される基を表す。Ｒ^１０１〜Ｒ^１０３はそれぞれ同一でも異なっていてもよい。Ｒ^１０４は、分岐若しくは非分岐の炭素数１〜６のアルキレン基を表す。） As the mercapto silane coupling agent, it is preferable to use a compound represented by the following formula (I). Thereby, there exists a tendency for the effect of this invention to be acquired more favorably.

(Wherein R ^{101 to} R ¹⁰³ are branched or unbranched alkyl groups having 1 to 12 carbon atoms, branched or unbranched alkoxy groups having 1 to 12 carbon atoms, or —O— (R ¹¹¹ —O) _b. -R ¹¹² (b pieces ^{by R 111} are .b pieces ^{by R 111} are optionally each be the same or different ^{.R 112} representing a divalent hydrocarbon group of branched or unbranched C1-30 is A branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms; Represents an integer of 1 to 30.) R ^{101 to} R ¹⁰³ may be the same or different, and R ¹⁰⁴ is a branched or unbranched alkylene group having 1 to 6 carbon atoms. Represents.)

R ^{101 to} R ¹⁰³ are branched or unbranched alkyl groups having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms), branched or unbranched carbon atoms having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms). An alkoxy group or a group represented by —O— (R ¹¹¹ —O) _b —R ¹¹² is represented. From the viewpoint that the effects of the present invention can be obtained satisfactorily, at least one of R ^{101 to} R ¹⁰³ is preferably a group represented by —O— (R ¹¹¹ —O) _b —R ¹¹² , and two are — More preferably, it is a group represented by O— (R ¹¹¹ —O) _b —R ¹¹² , and one is a branched or unbranched C 1-12 alkoxy group.

In —O— (R ¹¹¹ —O) _b —R ¹¹² of R ^{101 to} R ¹⁰³ , R ¹¹¹ represents branched or unbranched carbon atoms of 1 to 30 (preferably having 1 to 15 carbon atoms, more preferably 1 carbon atom). To 3) a divalent hydrocarbon group. Examples of the hydrocarbon group include an alkylene group, an alkenylene group, and an arylene group. Of these, an alkylene group is preferable.
b represents an integer of 1 to 30 (preferably 2 to 20, more preferably 3 to 7, still more preferably 5 to 6).
R ¹¹² represents a branched or unbranched monovalent hydrocarbon group having 1 to 30 carbon atoms (preferably 1 to 15 carbon atoms, more preferably 1 to 3 carbon atoms). Examples of the hydrocarbon group include an alkyl group, an alkenylene group, an aryl group, an aralkyl group, and the like. Of these, an alkyl group is preferable.

Specific examples of the group represented by —O— (R ¹¹¹ —O) _b —R ¹¹² include, for example, —O— (C ₂ H ₄ —O) ₅ —C ₁₁ H ₂₃ , —O— (C _{2 H 4 -O) 5 -C 12 H} 25, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) 5 -C 14 H 29, -O _{- (C 2 H 4 -O)} 5 -C 15 H 31, -O- (C 2 H 4 -O) 3 -C 13 H 27, -O- (C 2 H 4 -O) 4 -C 13 H _{27, -O- (C 2 H 4} -O) 6 -C 13 H 27, -O- (C 2 H 4 -O) 7 -C 13 H 27 and the like. Among _{these, -O- (C 2 H 4 -O} ) 5 -C 11 H 23, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) _{5 -C 15 H 31, -O- (} C 2 H 4 -O) 6 -C 13 H 27 are preferable.

Branched or unbranched carbon atoms 1 to 6 of R ¹⁰⁴ (preferably 1 to 5 carbon atoms) The alkylene group ^is the same as ^{R 111.}

Examples of the mercapto silane coupling agent represented by the formula (I) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane. And a compound represented by the following formula (Si363 manufactured by Evonik) and the like, and a compound represented by the following formula can be suitably used. These may be used alone or in combination of two or more.

When the silane coupling agent is contained, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass with respect to 100 parts by mass of silica. Hereinafter, it is more preferably 15 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

Although it does not specifically limit as carbon black, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762 etc. are mentioned. As commercial products, products such as Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Nisshinka Carbon Co., Ltd., Columbia Carbon Co., etc. are used. it can.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 90 m ² / g or more, more preferably 130 m ² / g or more, and preferably 200 m ² / g or less, more preferably 160 m ² / g. It is as follows. Within the above range, the effects of the present invention tend to be obtained more favorably.
Incidentally, _N 2 SA of carbon black, JIS K 6217-2: determined by 2001.

When carbon black is contained, the content of carbon black is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass or less, with respect to 100 parts by mass of the rubber component. Preferably it is 15 mass parts or less, More preferably, it is 10 mass parts or less. Within the above range, the effect of the present invention can be more suitably obtained.

The rubber composition preferably contains a resin having a softening point of 25 ° C. or higher. As a result, the compatibility of the rubber component can be improved, and the migration of chemicals to other tire members and the surface can be further suppressed. As a result, wet grip, wear resistance, steering stability and It is possible to improve the fuel efficiency and the performance maintenance characteristics during long-term use in a well-balanced manner.

As the resin, it is preferable to use at least one selected from the group consisting of a styrene resin, a terpene resin, a C5 resin, a C5 / C9 resin, a DCPD resin, and a rosin resin. Of these, styrene resins and C5 / C9 resins are more preferable.

The styrene resin is a polymer having a structural unit derived from a styrene monomer as a main component, and is a homopolymer of a styrene monomer (styrene, o-methylstyrene, etc.), two or more styrene monomers. In addition to the body copolymer, a styrene monomer and a copolymer with another monomer that can be copolymerized therewith are also included. Of these, a copolymer of α-methylstyrene and styrene is more preferable.

The terpene resin is a polymer having a structural unit derived from a terpene monomer as a main component, and includes a terpene monomer homopolymer, a copolymer of two or more terpene monomers, and a terpene. A copolymer (such as a terpene phenol resin) with a system monomer and another monomer that can be copolymerized therewith is also included.

The C5 resin is a polymer having a structural unit derived from the C5 fraction as a main component. In addition to the homopolymer of the C5 fraction, the copolymer of the two or more C5 fractions, the C5 fraction and the copolymer thereof. Also included are copolymers with other monomers that can be polymerized.

C5 / C9 resin is a polymer mainly composed of structural units derived from C5 fraction and C9 fraction, and in addition to C5 fraction and C9 fraction copolymer, C5 fraction and C9 fraction and these Copolymers with other monomers that can be copolymerized with the monomer are also included. Especially, the copolymer of a C5 fraction and a C9 fraction is preferable.

The DCPD resin is a polymer mainly composed of a structural unit derived from dicyclopentadiene (DCPD). In addition to a homopolymer of DCPD, a copolymer of DCPD and other monomers copolymerizable therewith Also mentioned.

The rosin resin is a polymer mainly composed of a structural unit derived from a rosin monomer, and includes a rosin monomer homopolymer, a copolymer of two or more rosin monomers, and a rosin. Examples thereof include copolymers with other monomers and other monomers that can be copolymerized therewith.

Commercially available products of the resin include, for example, Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yashara Chemical Co., Ltd., Tosoh Corp., Rutgers Chemicals Co., Ltd., BASF Co., Arizona Chemical Co., Ltd. , Nippon Shokubai Co., Ltd., JX Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd., etc. can be used.

Although the softening point of the said resin should just be 25 degreeC or more, Preferably it is 50 degreeC or more, More preferably, it is 80 degreeC or more, Preferably it is 120 degrees C or less, More preferably, it is 100 degrees C or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
In the present invention, the softening point of the resin is a temperature at which the sphere descends when the softening point defined in JIS K 6220-1: 2001 is measured with a ring and ball softening point measuring apparatus.

When the resin is contained, the content of the resin with respect to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 8 parts by mass or more. Moreover, it is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 60 parts by mass or less, and particularly preferably 55 parts by mass or less. Within the above range, wet grip, wear resistance and fuel efficiency during high-speed traveling, and workability can be improved in a well-balanced manner.

The rubber composition may contain oil.
Examples of the oil include process oil, vegetable oil and fat, or a mixture thereof. As the process oil, for example, a paraffin process oil, an aroma process oil, a naphthene process oil, or the like can be used. As vegetable oils and fats, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pineapple, tall oil, corn oil, rice bran oil, beet flower oil, sesame oil, Examples include olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. These may be used alone or in combination of two or more. Especially, since the effect of this invention is acquired favorably, process oil and vegetable oil are preferable, and aromatic process oils, such as a process distillate aromatic system extract (TDAE), are more preferable.

When oil is contained, the oil content is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 40 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain a wax.
The wax is not particularly limited, and examples thereof include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; synthetic waxes such as polymers such as ethylene and propylene. These may be used alone or in combination of two or more. Of these, petroleum wax is preferable, and paraffin wax is more preferable.

As the wax, for example, products such as Ouchi Shinsei Chemical Co., Ltd., Nippon Seiwa Co., Ltd., Seiko Chemical Co., Ltd. can be used.

When the wax is contained, the content of the wax is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 10 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain an anti-aging agent.
Examples of the antiaging agent include naphthylamine type antiaging agents such as phenyl-α-naphthylamine; diphenylamine type antiaging agents such as octylated diphenylamine and 4,4′-bis (α, α′-dimethylbenzyl) diphenylamine; N -Isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, etc. P-phenylenediamine-based antioxidants; quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymer; 2,6-di-t-butyl-4-methylphenol; Monophenolic antioxidants such as styrenated phenol; tetrakis- [methylene-3- (3 ', 5'-di-t-butyl- '- hydroxyphenyl) propionate] bis methane, tris, polyphenolic antioxidants, and the like. These may be used alone or in combination of two or more. Of these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferable.

As the anti-aging agent, for example, products such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., and Flexis Co. can be used.

When the anti-aging agent is contained, the content of the anti-aging agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 8 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain stearic acid.
A conventionally well-known thing can be used as a stearic acid, For example, products, such as NOF Corporation, NOF company, Kao Corporation, Wako Pure Chemical Industries, Ltd., and Chiba fatty acid company, can be used.

When stearic acid is contained, the content of stearic acid is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. Preferably it is 5 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain zinc oxide.
Conventionally known zinc oxide can be used, for example, Mitsui Kinzoku Mining Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd. Can be used.

When zinc oxide is contained, the content of zinc oxide is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. Preferably it is 5 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain sulfur.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur and the like generally used in the rubber industry. These may be used alone or in combination of two or more.

As the sulfur, for example, products such as Tsurumi Chemical Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Nihon Kiboshi Kogyo Co., Ltd., Hosoi Chemical Co., Ltd. can be used.

When sulfur is contained, the content of sulfur is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 5 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain an organic crosslinking agent.
Although it does not specifically limit as an organic crosslinking agent, Taoka Chemical Industry Co., Ltd. tackolol V200, Durelink HTS (1,6-hexamethylene-sodium dithiosulfate dihydrate) made by Flexis, KA9188 made by LANXESS And sulfur-containing compounds such as (1,6-bis (N, N′-dibenzylthiocarbamoyldithio) hexane) and organic peroxides such as dicumyl peroxide. These may be used alone or in combination of two or more.

When the organic crosslinking agent is contained, the content of the organic crosslinking agent is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 8 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain a vulcanization accelerator.
Examples of the vulcanization accelerator include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide (TMTD ), Tetrabenzylthiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N), and other thiuram vulcanization accelerators; N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl- 2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N, N′-diisopropyl-2-benzothiazole sulfenamide, etc. Sulfena De-based vulcanization accelerator; diphenylguanidine, it may be mentioned di-ortho-tolyl guanidine, guanidine-based vulcanization accelerators such as ortho tri ruby guanidine. These may be used alone or in combination of two or more. Of these, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferred because the effects of the present invention can be obtained more suitably.

When the vulcanization accelerator is contained, the content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. Part or less, more preferably 8 parts by weight or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

In addition to the above components, the rubber composition includes additives generally used in the tire industry, such as organic peroxides; fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica; Further, a plasticizer such as a liquid resin or an ester plasticizer; The content of these additives is preferably 0.1 to 200 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition can be produced, for example, by a method of kneading the above components using a rubber kneading apparatus such as an open roll or a Banbury mixer, and then vulcanizing.

As kneading conditions, in the base kneading step in which additives other than the vulcanizing agent and the vulcanization accelerator are kneaded, the kneading temperature is usually 100 to 180 ° C, preferably 120 to 170 ° C. In the final kneading step of kneading the vulcanizing agent and vulcanization accelerator, the kneading temperature is usually 120 ° C. or lower, preferably 85 to 110 ° C. Further, a composition obtained by kneading a vulcanizing agent and a vulcanization accelerator is usually subjected to vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190 ° C, preferably 150 to 185 ° C.

Although the said rubber composition can be used for each member of a tire, it is used suitably for a cap tread.

The tire of the present invention is produced by a usual method using the rubber composition.
That is, by extruding the rubber composition according to the shape of the cap tread at an unvulcanized stage, and molding it on a tire molding machine together with other tire members such as a base tread, Form an unvulcanized tire. The unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

In the tire, the rubber composition used for the base tread preferably contains SBR. It does not specifically limit as SBR, The thing similar to the rubber composition suitable for the above-mentioned cap tread can be used.

When SBR is contained, the content of SBR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass from the viewpoints of low fuel consumption, handling stability, and performance maintaining characteristics during long-term use. % Or more, more preferably 30% by mass or more, and from the viewpoint of low fuel consumption and mechanical strength, it is preferably 90% by mass or less, more preferably 80% by mass or less, and still more preferably 70% by mass or less. .

In the tire, the rubber composition used for the base tread preferably contains isoprene-based rubber. The isoprene-based rubber is not particularly limited, and the same rubber composition as that suitable for the cap tread described above can be used.

When the isoprene-based rubber is contained, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more, and the upper limit is not particularly limited. When it is within the above range, good mechanical strength can be obtained.

In the tire, the rubber composition used for the base tread preferably contains BR. It does not specifically limit as BR, The thing similar to the rubber composition suitable for the above-mentioned cap tread can be used.

When BR is contained, the content of BR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 60% by mass or less, more preferably 40% by mass. % Or less. Within the above range, good crack growth resistance can be obtained.

In addition to the above, the rubber composition used for the base tread in the tire described above is a normal tire rubber composition such as carbon black, silica, wax, stearic acid, anti-aging agent, zinc oxide, sulfur, vulcanization accelerator, etc. You may mix | blend the chemical | medical agent used for a thing suitably.

The type of the tire is not particularly limited and may be either a pneumatic tire or a solid tire, but a pneumatic tire is preferable.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
The microstructure and weight average molecular weight (Mw) of the rubber component used were evaluated as follows.

<Microstructure>
The content of the aromatic vinyl unit, vinyl butadiene unit, cis butadiene unit, and cis isoprene unit in the (co) polymer was measured with an NMR apparatus of AV400 manufactured by BRUKER and data analysis software TOP SPIN 2.1.

<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) method under the following conditions (1) to (8).
(1) Apparatus: HLC-8220 manufactured by Tosoh Corporation
(2) Separation column: Tosoh HM-H (two in series)
(3) Measurement temperature: 40 ° C
(4) Carrier: Tetrahydrofuran (5) Flow rate: 0.6 mL / min (6) Injection volume: 5 μL
(7) Detector: Differential refraction (8) Molecular weight standard: Standard polystyrene

<NR>: High-purity natural rubber produced by the method of Production Example 1 of Japanese Patent No. 56509797 (cisisoprene unit: 100% by mass, pH: 5, nitrogen content: 0.07% by mass, phosphorus content: 92 ppm, (Gel content: 6% by mass)
<BR>: BR150B manufactured by Ube Industries, Ltd. (vinyl structure in 100% by mass of butadiene unit: 2% by mass, cis-butadiene unit in 100% by mass of butadiene unit: 96% by mass)
<SBR1>: Modified S-SBR having an alkoxysilyl group at the terminal (styrene unit: 20% by mass, vinylbutadiene unit in 100% by mass of butadiene unit: 10% by mass, cisbutadiene unit in 100% by mass of butadiene unit: 60 (Mass%, Mw: 1.1 million)
<SBR2>: Modified S-SBR having a cisisoprene unit (1% by mass) and an alkoxysilyl group at the terminal (styrene unit: 10% by mass, vinylbutadiene unit in 100% by mass of butadiene unit: 4% by mass, Cis-butadiene unit in 100% by mass of butadiene unit: 80% by mass, Mw: 1 million)
<SBR3>: Modified S-SBR having an alkoxysilyl group at the terminal (styrene unit: 25% by mass, vinylbutadiene unit in 100% by mass of butadiene unit: 19% by mass, cisbutadiene unit in 100% by mass of butadiene unit: 40 (Mass%, Mw: 600,000)
<SBR4>: Modified S-SBR having an alkoxysilyl group at the terminal (styrene unit: 25% by mass, vinylbutadiene unit in 100% by mass of butadiene unit: 57% by mass, cisbutadiene unit in 100% by mass of butadiene unit: 20 (Mass%, Mw: 1 million)
<Hydrogenated SBR>: Hydrogenated product of modified SBR having an alkoxysilyl group at the terminal (styrene unit: 25% by mass, hydrogenation rate in 100% by mass of butadiene unit: 90% by mass, 100% by mass of butadiene unit before hydrogenation Vinyl butadiene unit in%: 0% by mass, cis butadiene unit in 100% by mass of butadiene unit before hydrogenation: 5% by mass, Mw: 895)
<Olefin copolymer>: Styrene-butadiene-ethylene copolymer polymerized by the method of Production Example 1 of Japanese Patent No. 4088258 (styrene unit: 20% by mass, vinylbutadiene unit: 10% by mass, cisbutadiene unit: 30% by mass, Ethylene unit: 40% by mass)
<Styrene-based TPE>: A hydrogenated product (modified with an alkoxysilyl group at the terminal) of Ti of a modified copolymer produced by changing the amount of styrene introduced by the method of Production Example 3 of JP-A-2014-105293 Styrene-hydrogenated butadiene-styrene block copolymer (modified SEBS)) (styrene unit: 28% by mass, hydrogenation rate of butadiene unit: 90% by mass, vinyl butadiene unit in 100% by mass of butadiene unit before hydrogenation: 0% by mass, cis-butadiene unit in 100% by mass of butadiene unit before hydrogenation: 5% by mass, Mw: 120,000)
<Silica>: Ultrasil 9000GR manufactured by Evonik (BET: 240 m ² / g, CTAB: 200 m ² / g)
<Silane coupling agent>: Si363 manufactured by Evonik
<Carbon black>: Dia Black SA (N ₂ SA: 137 m ² / g) manufactured by Mitsubishi Chemical Corporation
<Oil>: Vivatec 500 (TDAE oil) manufactured by H & R
<Resin 1 (styrene-based resin)>: SYLVARES SA85 (copolymer of α-methylstyrene and styrene, softening point: 85 ° C.) manufactured by Arizona Chemical Co., Ltd.
<Resin 2 (C5 / C9 series resin)>: ECR-373 (copolymer of C5 fraction and C9 fraction, softening point: 86 ° C.) manufactured by ExxonMobil
<Wax>: Sunflower wax manufactured by Koster Keunen (Sunflower seed-derived wax, softening point: 77 ° C.)
<Anti-aging agent>: Nocrack 6C (N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
<Zinc oxide>: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. <Sulfur>: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. <Organic crosslinking agent>: Vulcuren VP KA9188 (1,6-bis) manufactured by LANXESS (N, N′-dibenzylthiocarbamoyldithio) hexane)
<Stearic acid>: Beads stearic acid Tsubaki manufactured by NOF Corporation <Vulcanization accelerator 1>: Noxeller D (N, N'-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
<Vulcanization accelerator 2>: Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Co., Ltd.

<Method for producing rubber composition for cap tread>
According to the composition shown in Table 1, the materials described in the base kneading step were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel Co., Ltd. to obtain a kneaded product. . Next, the chemicals described in the finishing step were added to the kneaded product obtained, and kneaded for 5 minutes at 80 ° C. using an open roll to obtain an unvulcanized rubber composition for cap treads.
The obtained unvulcanized rubber composition for cap treads was press vulcanized with a 0.5 mm thick mold at 170 ° C. for 20 minutes to obtain a vulcanized rubber sheet.
The obtained vulcanized rubber sheet was evaluated as follows, and the results are shown in Table 1.
Moreover, in Table 1, the composition ratio in the rubber component is indicated by ◯ when the requirement of claim 1 is satisfied, and by × when the composition ratio is not satisfied.

<Viscoelasticity test>
Using a viscoelastic spectrometer, tan δ at −5 ° C. and tan δ at 80 ° C. of each vulcanized rubber sheet were measured under conditions of a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%. And about each of Formula (3) and (4), what satisfy | filled was shown by (circle) and what was not satisfied was shown by x.
In addition, using a viscoelastic spectrometer, each vulcanization at each temperature in increments of 5 ° C. from −90 ° C. to 40 ° C. under conditions of a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25%. The tan δ of the rubber sheet was measured, and the obtained viscoelastic spectrum was observed. A single peak was observed in a predetermined temperature range, and a negative peak was indicated by x.
Further, the Tg of each vulcanized rubber sheet was determined based on the viscoelastic spectrum, and those satisfying the formula (1) were indicated by ◯ and those not satisfied by x.

(Hardness measurement)
According to JIS K6253 “Method for testing hardness of vulcanized rubber and thermoplastic rubber”, the hardness (Hs) of each rubber test sheet at 23 ° C. was measured with a type A durometer, Unsatisfied items are indicated by ×.

<Microscope observation>
From each vulcanized rubber sheet, a thin piece having a thickness of about 100 nm is cut out using a microtome and observed using a transmission electron microscope (H-7100 manufactured by Hitachi, Ltd.). Those that are are indicated by ○, and those that are not are indicated by ×.

<Method for producing rubber composition for base tread>
According to the composition shown in Table 2, the materials described in the base kneading step were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. . Next, the chemicals described in the finishing step were added to the kneaded product obtained, and kneaded for 5 minutes at 80 ° C. using an open roll to obtain an unvulcanized rubber composition for base tread.

<Method for producing test tire>
The unvulcanized rubber composition for cap treads obtained above is molded into a cap tread shape, and the unvulcanized rubber composition for base treads is molded into a base tread shape, respectively, and together with other tire members on a tire molding machine An unvulcanized tire was formed by bonding and vulcanized at 170 ° C. for 10 minutes to produce a test tire (size: 215 / 55R16, passenger vehicle tire).
The obtained test tire was evaluated as follows, and the results are shown in Table 1.

<Wet grip>
Each test tire is mounted on a domestic 2000cc FF vehicle, running on a wet 25 ° C road surface, stepping on the lock brake at a speed of 150km / h, measuring the stopping distance required to stop, Thus, Comparative Example 1 was indexed as 100. The larger the index, the better the wet grip (wet braking performance) during high speed running.
(Wet grip index) = (Stop distance of Comparative Example 1) / (Stop distance of each formulation) × 100

<Abrasion resistance 1>
Each test tire is mounted on a domestic FF2000cc car, running on the same tire surface including wet roads and sharp curves under an air temperature of 22-27 ° C, and a cap after a running distance of 5000 km at a speed of 100-150 km / hour The groove depth of the tread portion was measured, the travel distance when the groove depth decreased by 1 mm was calculated, and indexed with Comparative Example 1 as 100 by the following formula. The larger the index, the better the wear resistance during high speed running.
(Abrasion resistance 1 index) = (travel distance when 1 mm groove depth of each composition is reduced) / (travel distance when tire groove of Comparative Example 1 is reduced by 1 mm) × 100

<Abrasion resistance 2>
In the tire after the test for abrasion resistance 1, the presence or absence of chipping or tread chipping was confirmed and evaluated according to the following criteria. The larger the index, the better the wear resistance during high speed running.
100: Little chipping or chipping is observed 80: Some small chipping is observed 60: Chipping or chipping is observed 40: Large tread chipping is observed

<Steering stability>
Two drivers sensory-evaluated the stability of the control during the initial running in the test of wear resistance 1 according to the following criteria with Comparative Example 1 as 100, and the results were averaged (steering stability index). The larger the index, the better the steering stability at high speeds.
140: Excellent 120: Excellent 110: Excellent 100: Equivalent to Comparative Example 1 80: Slightly inferior 70: Inferior 60: Very inferior

<Low fuel consumption>
Using a rolling resistance tester, each test tire was mounted on a rim and measured for rolling resistance when running at an internal pressure (230 kPa), a load (3.43 kN), and a speed (160 km / h). Comparative Example 1 It is displayed as an index when the value is 100 (low fuel consumption index). The larger the index, the better the fuel economy when traveling at high speed.

<Maintaining performance after long-term use>
The tire after the test for abrasion resistance 1 was removed from the car and left for half a year in a state exposed to outdoor sunlight and wind and rain. After that, it was mounted on the same vehicle (domestic FF2000cc) as the test for wear resistance 1, and the driving stability and brake response when running on a wet road surface or a road surface including a sharp curve at a temperature of 25 ° C were wear resistant. Compared with the start of test No. 1, the following criteria were evaluated (performance maintenance index). A larger index indicates less performance degradation.
100: Almost no change 90: Feels a slight deterioration in performance 80: Feels a slight deterioration in performance 60: Feels a considerable deterioration in performance

From Table 1, in 100 mass% of the rubber component, the content of the component derived from the aromatic vinyl monomer is 3 to 25 mass%, the component derived from the butadiene monomer and having a vinyl structure has a content of 0 to 15 1% to 90% by mass of a component derived from a butadiene monomer and having a cis structure, and 1 to 6% by mass of a component derived from an isoprene monomer and having a cis structure In the examples in which the physical properties after vulcanization satisfy the formulas (1) and (2), wet grip, wear resistance, handling stability and fuel efficiency during high-speed driving are improved in a well-balanced manner, and after long-term use There was little performance degradation.
Examples include those near the upper limit of formula (1), those near the lower limit of formula (1), those near the upper limit of formula (2), those near the lower limit of formula (2), formula (3 ) In the vicinity of the lower limit and in the vicinity of the upper limit of formula (4).

Claims (13)

In 100% by mass of rubber component,
The content of the component derived from the aromatic vinyl monomer is 3 to 25% by mass,
A component derived from a butadiene monomer and having a vinyl structure has a content of 0 to 15% by mass,
A component derived from a butadiene monomer and having a cis structure has a content of 1 to 90% by mass,
The content of the component derived from the isoprene monomer and having a cis structure is 1 to 6% by mass,
A rubber composition for tires having physical properties after vulcanization satisfying the following formulas (1) and (2).
−25 ° C. <Tg <0 ° C. (1)
Tg: temperature at which tan δ is maximum when viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25% 65 <Hs <75 (2)
Hs: Hardness at 23 ° C. measured according to JIS K6253 The rubber composition for a tire according to claim 1, wherein the viscoelasticity spectrum when the viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 0.25% has a single peak at -80 ° C or higher. object. The tire rubber composition according to claim 2, wherein the viscoelastic spectrum has a single peak at −90 ° C. or higher. The tire rubber composition according to any one of claims 1 to 3, wherein physical properties after vulcanization satisfy the following formulas (3) and (4).
tan δ1> 0.80 (3)
tan δ2 <0.15 (4)
tan δ1: tan δ at −5 ° C. when viscoelasticity measurement is performed at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2%
tan δ2: tan δ at 80 ° C. when measuring viscoelasticity at a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain amplitude of 2% The tire component according to any one of claims 1 to 4, wherein the rubber component includes a solution-polymerized styrene-butadiene rubber having a vinyl structure content of 25% by mass or less in 100% by mass of a component derived from a butadiene monomer. Rubber composition. The tire rubber composition according to claim 5, wherein the solution-polymerized styrene butadiene rubber has a weight average molecular weight of 800,000 or more. The tire according to any one of claims 1 to 4, wherein the rubber component includes at least one selected from the group consisting of a hydrogenated styrene butadiene rubber, a styrene thermoplastic elastomer, and an olefin-conjugated diene-styrene copolymer. Rubber composition. Containing silica,
The rubber composition for tires according to any one of claims 1 to 7, wherein a content of the silica is 100 to 300 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition for tires according to any one of claims 1 to 7, wherein the rubber component has a single morphology. Contains a resin with a softening point of 25 ° C. or higher,
The rubber composition for tires according to any one of claims 1 to 8, wherein a content of the resin is 1 to 60 parts by mass with respect to 100 parts by mass of the rubber component. The tire rubber composition according to claim 10, wherein the resin is at least one selected from the group consisting of a styrene resin, a terpene resin, a C5 resin, a C5 / C9 resin, a DCPD resin, and a rosin resin. object. It is a rubber composition for cap treads, The rubber composition for tires in any one of Claims 1-11. A cap tread composed of the rubber composition according to claim 12;
A tire including a base tread produced using a rubber composition having a styrene butadiene rubber content of 10% by mass or more in 100% by mass of a rubber component.