WO2020261873A1 - Tire - Google Patents

Abstract

The present invention provides a tire being capable of improved overall performance including wet grip performance and wear resistance. The present invention pertains to a tire comprising a tread composed of a rubber composition which contains a rubber component and a silane coupling agent, and which has at least 37 mass% of an ash content and at most 0.75 mass% of a sulfur content after acetone extraction.

Description

tire

The present invention relates to a tire.

It is known that the wet grip performance is improved by blending a large amount of silica or a softening agent (see, for example, Patent Document 1). However, in this case, as the proportion of the polymer component in the rubber composition decreases, the tensile drag tends to decrease and the wear resistance tends to decrease.

On the other hand, it is known that the wear resistance is improved by using a mercapto-based silane coupling agent as a silane coupling agent to be blended with silica (see, for example, Patent Document 2).

Japanese Patent No. 6033786 Japanese Unexamined Patent Publication No. 2012-12205

However, when a large amount of silica or a softening agent is added to improve the wet grip performance, sufficient wear resistance may not be ensured even if a mercapto-based silane coupling agent is used.

An object of the present invention is to provide a tire capable of solving the above problems and improving the overall performance of wet grip performance and wear resistance.

When the present inventors examined a method for solving the above problems, they focused on ash, which is a component derived from silica, zinc oxide, aluminum hydroxide, magnesium sulfate, a processing aid, etc. in the rubber composition. Then, it was found that the correlation between the ash content and the wet grip performance is high, and the wet grip performance tends to be improved by increasing the ash content. However, when the proportion of ash is increased, the rubber composition may become too hard and the wear resistance may decrease.

Therefore, as a result of further studies by the present inventors, attention was paid to the amount of sulfur in the rubber composition after vulcanization after extraction with acetone. Of the sulfur contained in the rubber composition, the sulfur involved in cross-linking is bound to the polymer, vulcanization accelerator and zinc oxide, and is considered not to be eluted by acetone extraction. Therefore, sulfur after acetone extraction From the amount, the amount of sulfur involved in cross-linking can be estimated.

By reducing the amount of sulfur after acetone extraction, that is, the sulfur content involved in cross-linking, the number of polysulfide bonds that crosslink the polymer chain is reduced, and the amount of sulfur atoms released into the rubber during use is reduced. As a result, the rubber composition is less likely to be cured over time, and even when the proportion of ash is increased, good wear resistance can be ensured, and both wet grip performance and wear resistance can be achieved at the same time. I came up with the headline and the present invention.

That is, the present invention comprises a tire comprising a rubber component and a silane coupling agent, and having a tread composed of a rubber composition having an ash content of 37% by mass or more and a sulfur content after acetone extraction of 0.75% by mass or less. Regarding.

In the rubber composition, the amount of sulfur is preferably 0.65% by mass or less.

In the rubber composition, the content of silica with respect to 100 parts by mass of the rubber component is preferably 110 parts by mass or more.

The sulfur content of the silane coupling agent is preferably 10% by mass or less.

In the rubber composition, the content of carbon black with respect to 100 parts by mass of the rubber component is preferably 10 parts by mass or less.

In the rubber composition, the content of the amide compound or the nonionic surfactant having an SP value of 9.0 or more with respect to 100 parts by mass of the rubber component is preferably 0.1 part by mass or more.

It is preferable that the rubber composition contains a thiuram-based vulcanization accelerator.

It is preferable that the rubber composition contains at least one inorganic filler selected from the group consisting of aluminum hydroxide, alumina, zirconium oxide, magnesium sulfate, aluminum silicate, potassium carbonate and silicon carbide.

It is preferable that the rubber composition contains a solid resin.

According to the present invention, a tire comprising a tread containing a rubber component and a silane coupling agent and having a rubber composition having an ash content of 37% by mass or more and a sulfur content after acetone extraction of 0.75% by mass or less. Therefore, the overall performance of wet grip performance and wear resistance can be improved.

The tire of the present invention includes a tread containing a rubber component and a silane coupling agent, and is composed of a rubber composition having an ash content of 37% by mass or more and a sulfur content after acetone extraction of 0.75% by mass or less.

Since the rubber composition contains a rubber component and a silane coupling agent and has an ash content of a predetermined amount or more, excellent wet grip performance can be obtained. Further, as described above, when the proportion of ash is high, the wear resistance may decrease. However, since the amount of sulfur in the rubber composition after extraction with acetone is less than a predetermined amount, the rubber composition is cured over time. Is less likely to occur, and excellent wear resistance can be obtained. It is presumed that these actions improve the overall performance of wet grip performance and wear resistance.

In the rubber composition, the ash content may be 37% by mass or more, preferably 38% by mass or more, more preferably 39% by mass or more, and preferably 55% by mass or less, more preferably 50% by mass. It is mass% or less, more preferably 44 mass% or less. Within the above range, the effect tends to be better obtained.

As described above, the ash content is a component derived from silica, zinc oxide, aluminum hydroxide, magnesium sulfate, a processing aid, etc. in the rubber composition, and the ash content can be adjusted from the blending amount of these components.
In addition, the amount of ash can be measured by the method described in Examples described later.

In the above rubber composition, the amount of sulfur after acetone extraction may be 0.75% by mass or less, preferably 0.65% by mass or less, and more preferably 0.45% by mass or more. Is 0.55% by mass or more, more preferably 0.60% by mass or more. Within the above range, both wet grip performance and wear resistance tend to be obtained, and vulcanization adhesion between the tread and the adjacent rubber tends to be satisfactorily obtained.

As described above, the amount of sulfur after acetone extraction is considered to be derived from the sulfur content involved in cross-linking, that is, the sulfur content contained in powdered sulfur, hybrid cross-linking agent, vulcanization accelerator, silane coupling agent, and the like. , The amount of sulfur after acetone extraction can be adjusted from these blending amounts. Sulfur contained in process oil, resin, etc. is considered to be removed by acetone extraction without participating in cross-linking.
In addition, the amount of sulfur after acetone extraction can be measured by the method described in Examples described later.

Examples of the rubber component that can be used in the rubber composition include isoprene-based rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber (CR). ), Diene rubber such as butyl rubber (IIR). The rubber component may be used alone or in combination of two or more. Of these, SBR, BR, and isoprene-based rubber are preferable, and SBR and BR are more preferable.

Here, the rubber component is a polymer having a weight average molecular weight (Mw) of preferably 150,000 or more, more preferably 350,000 or more. The upper limit of Mw is not particularly limited, but is preferably 4 million or less, more preferably 3 million or less.

The SBR is not particularly limited, and for example, emulsion polymerization SBR (E-SBR), solution polymerization SBR (S-SBR), and the like, which are common in the tire industry, can be used. These may be used alone or in combination of two or more.

The amount of styrene in SBR is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably. Is 35% by mass or less. Within the above range, the effect tends to be better obtained.

The vinyl content of SBR is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less. Within the above range, the effect tends to be better obtained.

The SBR may be a non-modified SBR or a modified SBR.
The modified SBR may be any SBR having a functional group that interacts with a filler such as silica. For example, at least one end of the SBR is modified with a compound having the above functional group (modifying agent). SBR (terminal modified SBR having the above functional group at the end), main chain modified SBR having the above functional group in the main chain, and main chain terminal modified SBR having the above functional group in the main chain and the end (for example, in the main chain) Main chain terminal modified SBR having the above functional group and having at least one end modified with the above modifying agent) or a polyfunctional compound having two or more epoxy groups in the molecule, which is modified (coupling) with a hydroxyl group. And terminally modified SBR into which an epoxy group has been introduced. These may be used alone or in combination of two or more.

Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group and a disulfide. Examples thereof include a group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group and an epoxy group. .. In addition, these functional groups may have a substituent. Among them, an amino group (preferably an amino group in which the hydrogen atom of the amino group is replaced with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxy group having 1 to 6 carbon atoms). An alkoxysilyl group having 1 to 6 carbon atoms) and an amide group are preferable.

As the SBR, for example, products such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Co., Ltd., and Zeon Corporation can be used.

The content of SBR in 100% by mass of the rubber component is preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, and preferably 95% by mass or less, more preferably 95% by mass or less. It is 90% by mass or less. Within the above range, the effect tends to be better obtained.

The BR is not particularly limited, and a BR commonly used in the tire industry can be used. For example, BR having a high cis content, BR containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR), butadiene rubber synthesized using a rare earth element catalyst (rare earth BR), and modified with a tin compound. Examples thereof include those commonly used in the tire industry, such as tin-modified butadiene rubber (tin-modified BR). These may be used alone or in combination of two or more. Of these, rare earth-based BRs are preferable because they can further improve wear resistance while maintaining good wet grip performance.

Rare earth-based BR is a butadiene rubber synthesized by using a rare earth element-based catalyst, and has a feature of high cis content and low vinyl content. As the rare earth BR, a general-purpose product in tire manufacturing can be used.

As the rare earth element-based catalyst, known catalysts can be used, and examples thereof include lanthanum series rare earth element compounds, organoaluminum compounds, aluminoxanes, halogen-containing compounds, and catalysts containing a Lewis base, if necessary. Of these, an Nd-based catalyst using a neodymium (Nd) -containing compound as the lanthanum-series rare earth element compound is preferable.

The cis content of BR is preferably 90% by mass or more, more preferably 93% by mass or more, still more preferably 95% by mass or more, and the upper limit is not particularly limited. Within the above range, the effect tends to be better obtained.

The vinyl content of BR is preferably 1.8% by mass or less, more preferably 1.0% by mass or less, still more preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less. Within the above range, the effect tends to be better obtained.

The BR may be either a non-modified BR or a modified BR.
Examples of the modified BR include modified BRs into which the above-mentioned functional groups have been introduced. The preferred embodiment is the same as for the modified SBR.

As the BR, for example, products such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and ZEON Corporation can be used.

The content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably. It is 30% by mass or less. Within the above range, the effect tends to be better obtained.

The total content of SBR and BR in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, and particularly preferably 90% by mass or more, 100% by mass. It may be% by mass. Within the above range, the effect tends to be better obtained.

Examples of the isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR and the like. As the NR, for example, SIR20, RSS # 3, TSR20 and the like, which are common in the tire industry, can be used. The IR is not particularly limited, and for example, an IR 2200 or the like that is common in the tire industry can be used. Modified NR includes deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc., and modified NR includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Examples of the modified IR include 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, natural rubber is preferable.

In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are gel permeation chromatographs (GPC) (GPC-8000 series manufactured by Toso Co., Ltd., detector: differential refractometer, column: It can be obtained by standard polystyrene conversion based on the measured value by TSKGEL SUPERMULTIPORE HZ-M manufactured by Toso Co., Ltd.
The cis content (cis-1,4-bonded butadiene unit amount) and vinyl content (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectrum analysis, and the amount of styrene is measured by ¹ H-NMR. Can be measured by.

The rubber composition preferably contains silica as a reinforcing filler.
Examples of silica include dry silica (silicic anhydride) and wet silica (hydrous silicic acid), but wet silica is preferable because it contains a large amount of silanol groups. These may be used alone or in combination of two or more.

Nitrogen adsorption specific surface area _(N 2 SA) of silica is preferably ^{60 m} 2 / g or more, more preferably 150 meters ² / g or more, further preferably 220 m ² / g or more, and preferably not more than 320 m ² / g , More preferably 280 m ² / g or less. Within the above range, the effect tends to be better obtained. In particular, by using silica having an N ₂ SA of 220 m ² / g or more, wear resistance can be further improved while maintaining good wet grip performance.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

As the silica, for example, products such as Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Corporation can be used.

The content of silica is preferably 90 parts by mass or more, more preferably 110 parts by mass or more, further preferably 130 parts by mass or more, and preferably 200 parts by mass or less, based on 100 parts by mass of the rubber component. It is preferably 180 parts by mass or less, and more preferably 160 parts by mass or less. Within the above range, the effect tends to be better obtained.

The content of silica in 100% by mass of the reinforcing filler is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and particularly preferably 80% by mass or more. The upper limit is not particularly limited and may be 100% by mass, but is preferably 98% by mass or less.

The rubber composition contains a silane coupling agent.
The silane coupling agent is not particularly limited, and 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-trimethoxysilylethyl) ) Disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3- Sulfates such as triethoxysilylpropylmethacrylate monosulfide, mercaptos such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane, vinyls such as vinyltriethoxysilane and vinyltrimethoxysilane, 3-aminopropyl Amino series such as triethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy series such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, 3-nitropropyltrimethoxysilane, 3- Examples thereof include nitro type such as nitropropyltriethoxysilane and chloro type such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. As commercially available products, for example, products such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. can be used. These may be used alone or in combination of two or more.

As the silane coupling agent, a silane coupling agent having a sulfur content of 10% by mass or less (preferably 5% by mass or less) can be preferably used. Among the above-mentioned silane coupling agents, except for sulfide type, the sulfur content is usually 10% by mass or less. The lower limit of the sulfur content is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more.
The sulfur content of the silane coupling agent can be measured by the same method as the "sulfur content after acetone extraction" described in Examples described later.

As the silane coupling agent having a sulfur content of 10% by mass or less, a silane coupling agent containing a binding unit A represented by the following formula (I) and a binding unit B represented by the following formula (II) is preferably used. it can.

(In the formula, v is an integer of 0 or more, w is an integer of 1 or more. R ¹¹ is hydrogen, halogen, an alkyl group having 1 to 30 branched or unbranched carbon atoms, and 2 to 2 branched or unbranched carbon atoms. 30 alkenyl groups, branched or unbranched alkynyl groups having 2 to 30 carbon atoms, or hydrogens at the ends of the alkyl groups substituted with hydroxyl groups or carboxyl groups. R ¹² has branched or unbranched carbon atoms. It represents 1 to 30 alkylene groups, branched or non-branched alkenylene groups having 2 to 30 carbon atoms, or branched or non-branched alkynylene groups having 2 to 30 carbon atoms. A ring structure is formed by R ¹¹ and R ^12. May be.)

In the silane coupling agent containing the binding unit A represented by the formula (I) and the binding unit B represented by the formula (II), the content of the binding unit A is preferably 30 mol% or more, more preferably 50 mol. % Or more, preferably 99 mol% or less, more preferably 90 mol% or less. The content of the binding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, preferably 70 mol% or less, more preferably 65 mol% or less. More preferably, it is 55 mol% or less. The total content of the binding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and further preferably 100 mol%.
The content of the binding units A and B is an amount including the case where the binding units A and B are located at the ends of the silane coupling agent. The form in which the binding units A and B are located at the ends of the silane coupling agent is not particularly limited, and a unit corresponding to the formulas (I) and (II) representing the binding units A and B may be formed. ..

Regarding R ¹¹ in the formulas (I) and (II), examples of the halogen include chlorine, bromine and fluorine. Examples of the branched or non-branched alkyl group having 1 to 30 carbon atoms include a methyl group and an ethyl group. Examples of the branched or non-branched alkenyl group having 2 to 30 carbon atoms include a vinyl group and a 1-propenyl group. Examples of the branched or non-branched alkynyl group having 2 to 30 carbon atoms include an ethynyl group and a propynyl group.

Formula (I), the ^{R 12} in (II), Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms, an ethylene group, a propylene group, and the like. Examples of the branched or non-branched alkenylene group having 2 to 30 carbon atoms include a vinylene group and a 1-propenylene group. Examples of the branched or non-branched alkynylene group having 2 to 30 carbon atoms include an ethynylene group and a propynylene group.

In a silane coupling agent containing the binding unit A represented by the formula (I) and the binding unit B represented by the formula (II), the number of repetitions (v) of the binding unit A and the number of repetitions (w) of the binding unit B The total number of repetitions (v + w) is preferably in the range of 3 to 300.

As the silane coupling agent having a sulfur content of 10% by mass or less, a silane coupling agent represented by the following formula (S1) can also be preferably used.

(In the formula, R ¹⁰¹ to R ¹⁰³ are branched or non-branched alkyl groups having 1 to 12 carbon atoms, branched or non-branched alkoxy groups having 1 to 12 carbon atoms, or —O— (R ¹¹¹ −O) _d. -R ¹¹² (d R ^111s represent branched or non-branched divalent hydrocarbon groups having 1 to 30 carbon atoms. The d R ^111s may be the same or different, respectively. R ¹¹² may be the same or different. It represents a branched or non-branched alkyl group having 1 to 30 carbon atoms, a branched or non-branched 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 a group represented by (1 to 30). R ¹⁰¹ to R ¹⁰³ may be the same or different, respectively. R ¹⁰⁴ is a branched or non-branched alkylene group having 1 to 6 carbon atoms. Represents.)

R ¹⁰¹ to R ¹⁰³ are branched or non-branched alkyl groups having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms), and branched or non-branched alkyl groups having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms). Represents an alkoxy group or a group represented by —O— (R ¹¹¹⁻ O) _d— R ¹¹² . From the viewpoint that a good effect can be obtained, it is preferable that at least one of R ¹⁰¹ to R ¹⁰³ is a group represented by -O- (R ^111- O) _d- R ¹¹² , and two are -O- (. R ^111- O) It is more preferable that the group is represented by _d- R ¹¹² and one is a branched or non-branched alkoxy group having 1 to 12 carbon atoms.

In -O- (R ^111- O) _d- R ¹¹² of R ¹⁰¹ to R ¹⁰³ , R ¹¹¹ has 1 to 30 branched or non-branched carbon atoms (preferably 1 to 15 carbon atoms, more preferably 1 carbon atom). Represents the divalent hydrocarbon group of 3). Examples of the hydrocarbon group include an alkylene group, an alkenylene group, an arylene group and the like. Of these, an alkylene group is preferable.
d represents an integer of 1 to 30 (preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, preferably 20 or less, more preferably 7 or less, still more preferably 6 or less).
R ¹¹² represents a branched or non-branched 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) _d- 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 can be mentioned. Among them, -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.

The branched or non-branched alkylene group of R ¹⁰⁴ having 1 to 6 carbon atoms (preferably 1 to 5 carbon atoms) is the same as that of R ¹¹¹ .

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

As the silane coupling agent having a sulfur content of 10% by mass or less, a silane coupling agent represented by the following formula (S2) can also be preferably used.

(In the formula, R ¹⁰⁰¹ is -Cl, -Br, -OR ¹⁰⁰⁶ , -O (O =) CR ¹⁰⁰⁶ , -ON = CR ¹⁰⁰⁶ R ¹⁰⁰⁷ , -NR ¹⁰⁰⁶ R ¹⁰⁰⁷ and-(OSiR ¹⁰⁰⁶ R ¹⁰⁰⁷ ) _h (OSiR ¹⁰⁰⁶ R ¹⁰⁰⁷ R ¹⁰⁰⁸⁾ a monovalent group selected from ^{(R 1006, R 1007} and ^{R 1008} may be the same or different, be each a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms , H has an average value of 1 to 4), R ¹⁰⁰² is R ¹⁰⁰¹ , a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ^{1003 is-} [O (R ¹⁰⁰⁹ O) _j. ] ^-Group (R ¹⁰⁰⁹ is an alkylene group having 1 to 18 carbon atoms, j is an integer of 1 to 4), R ¹⁰⁰⁴ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ¹⁰⁰⁵ is 1 carbon atom. It represents a monovalent hydrocarbon group of to 18, and x, y and z are numbers that satisfy the relationship of x + y + 2z = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, 0 ≦ z ≦ 1).

In formula (S2), R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ are independently ^derived from a linear, cyclic or branched alkyl group having 1 to 18 carbon atoms, an alkenyl group, an aryl group and an aralkyl group, respectively. It is preferable that the group is selected from the group. When R ¹⁰⁰² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is selected from the group consisting of a linear, cyclic or branched alkyl group, an alkenyl group, an aryl group and an aralkyl group. It is preferably a group. R ¹⁰⁰⁹ is preferably a linear, cyclic or branched alkylene group, and particularly preferably linear. ^R1004 is, for example, an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 2 to 18 carbon atoms, a cycloalkylene group having 5 to 18 carbon atoms, a cycloalkylalkylene group having 6 to 18 carbon atoms, and an arylene having 6 to 18 carbon atoms. Examples thereof include an aralkylene group having 7 to 18 carbon atoms. The alkylene group and the alkenylene group may be linear or branched, and the cycloalkylene group, the cycloalkylalkylene group, the arylene group and the aralkylene group have a functional group such as a lower alkyl group on the ring. You may be doing it. As the R ¹⁰⁰⁴ , an alkylene group having 1 to 6 carbon atoms is preferable, and a linear alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group and a hexamethylene group are particularly preferable.

Specific examples of R ¹⁰⁰² , R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ^{1008 in} the formula (S2) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and sec-butyl. Group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclo Examples thereof include a hexenyl group, a phenyl group, a tolyl group, a xsilyl group, a naphthyl group, a benzyl group, a phenethyl group and a naphthylmethyl group.
Examples of R ¹⁰⁰⁹ in the formula (S2) include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, a hexylene group and the like as the linear alkylene group, and examples of the branched alkylene group include a branched alkylene group. Examples thereof include an isopropylene group, an isobutylene group and a 2-methylpropylene group.

Specific examples of the silane coupling agent represented by the formula (S2) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, and 3-. Lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoy Luciopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthio Examples thereof include ethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, and 2-lauroylthioethyltrimethoxysilane. These may be used alone or in combination of two or more. Of these, 3-octanoylthiopropyltriethoxysilane is particularly preferable.

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 or less, more preferably 15 parts by mass or less, based on 100 parts by mass of silica. Is. Within the above range, the effect tends to be better obtained.

The rubber composition may contain carbon black as a reinforcing filler.
The carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 80 m ² / g or more, more preferably 100 m ² / g or more, and preferably 200 m ² / g or less, more preferably 150 m ² / g. It is as follows. Within the above range, the effect tends to be better obtained.
In this specification, N ₂ SA of carbon black is a value measured in accordance with JIS K6217-2: 2001.

As carbon black, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nikka Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc. Can be used.

The content of carbon black is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass or less in order to suppress the generation of cracks due to ultraviolet rays with respect to 100 parts by mass of the rubber component. , More preferably 10 parts by mass or less. Carbon black forms a thick gel layer with the polymer. This gel layer improves wear resistance, but its wet grip performance is inferior to that of silica. When the content of carbon black is within the above range, good wet grip performance and wear resistance tend to be ensured.

The rubber composition preferably contains an amide compound and / or a nonionic surfactant having an SP value of 9.0 or more.

The amide compound is not particularly limited, and examples thereof include fatty acid amides and fatty acid amide esters. These may be used alone or in combination of two or more. Of these, fatty acid amides are preferable, and a mixture of fatty acid amides and fatty acid amide esters is more preferable.

The amide compound may be a mixture with a fatty acid metal salt.
Examples of the metal constituting the fatty acid metal salt include potassium, sodium, magnesium, calcium, barium, zinc, nickel, molybdenum and the like. These may be used alone or in combination of two or more. Of these, alkaline earth metals such as calcium and zinc are preferable, and calcium is more preferable.

The fatty acid constituting the fatty acid metal salt may be a saturated fatty acid or an unsaturated fatty acid. Examples of the saturated fatty acid include decanoic acid, dodecanoic acid, and stearic acid, and examples of the unsaturated fatty acid include oleic acid. , Elaidic acid and the like. These may be used alone or in combination of two or more. Of these, saturated fatty acids are preferable, and stearic acid is more preferable. Moreover, oleic acid is preferable as an unsaturated fatty acid.

The fatty acid amide may be a saturated fatty acid amide or an unsaturated fatty acid amide. Examples of the saturated fatty acid amide include stearic acid amide and behenic acid amide, and examples of the unsaturated fatty acid amide include oleic acid amide. Examples include erucic acid amide. These may be used alone or in combination of two or more. Of these, unsaturated fatty acid amides are preferable, and oleic acid amides are more preferable.

The fatty acid amide ester may be a saturated fatty acid amide ester or an unsaturated fatty acid amide ester, and examples of the saturated fatty acid amide ester include stearic acid amide ester and behenic acid amide ester. Examples thereof include oleic acid amide ester and erucic acid amide ester. These may be used alone or in combination of two or more. Of these, unsaturated fatty acid amide esters are preferable, and oleic acid amide esters are more preferable.

As the amide compound, for example, products such as NOF CORPORATION, Stractol, and Lanxess can be used.

The content of the amide compound is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, and preferably 4 by mass with respect to 100 parts by mass of the rubber component. It is less than a part by mass, more preferably 2 parts by mass or less. Within the above range, the bleed layer on the tread surface tends to be soft, and the initial grip performance tends to be good.
In the present specification, when the amide compound is a mixture with the fatty acid metal salt, the content of the amide compound also includes the amount of the fatty acid metal salt contained in the amide compound.

When the fatty acid metal salt is blended separately from the amide compound, the content thereof is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, and more preferably. Is 4 parts by mass or less, more preferably 2 parts by mass or less. Within the above range, the deterioration of wear resistance tends to be small.

The nonionic surfactant (nonionic surfactant having an SP value of 9.0 or more) is not particularly limited, and is, for example, a nonionic surfactant represented by the following formula (1); the following formula. Nonionic surfactant represented by (2); Pluronic nonionic surfactant; Polyoxyethylene sorbitan monostearate, Polyoxyethylene sorbitan monooleate, Polyoxyethylene sorbitan monopalmitate, Trioleic acid Solbitan fatty acid esters such as polyoxyethylene sorbitan, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan tripalmitate; polyoxyethylene dodecyl ether, polyoxyethylene lauryl ether, polyoxyethylene 2-ethylhexyl ether, polyoxyethylene oleyl Examples thereof include polyoxyethylene alkyl ethers such as ether, ethylene glycol dibutyl ether, ethylene glycol dilauryl ether, ethylene glycol di2-ethylhexyl ether, and ethylene glycol dioleyl ether. These may be used alone or in combination of two or more. Of these, a pluronic nonionic surfactant is preferable.

(In the formula, R ¹ represents a hydrocarbon group having 6 to 26 carbon atoms. D represents an integer.)

(In the formula, R ² and R ³ represent the same or different hydrocarbon groups having 6 to 26 carbon atoms. E represents an integer.)

Examples of the nonionic surfactant represented by the formula (1) include ethylene glycol monooleate, ethylene glycol monopalmiate, ethylene glycol monopalmitate, ethylene glycol monopaxenate, ethylene glycol monolinoleate, and ethylene glycol monolith. Examples thereof include norenate, ethylene glycol monoarachidonate, ethylene glycol monostearate, ethylene glycol monocetylate, and ethylene glycol monolaurate.

Examples of the nonionic surfactant represented by the formula (2) include ethylene glycol dioleate, ethylene glycol dipalmiate, ethylene glycol dipalmitate, ethylene glycol dipaxenate, ethylene glycol dilinolete, and ethylene glycol dilinole. Nate, ethylene glycol diarachidonate, ethylene glycol distearate, ethylene glycol disetylate, ethylene glycol dilaurate and the like can be mentioned.

The pluronic nonionic surfactant is also called polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxypropylene block polymer, or polypropylene glycol ethylene oxide adduct, and is generally represented by the following formula (3). It is an ionic surfactant. As represented by the following formula (3), the pluronic nonionic surfactant has a hydrophilic group composed of an ethylene oxide structure on both sides, and is composed of a propylene oxide structure so as to be sandwiched between the hydrophilic groups. Has a hydrophobic group to be treated.

(In the formula, a, b, and c represent integers.)

The degree of polymerization of polypropylene oxide block, which is a pluronic nonionic surfactant (b in formula (3)), and the amount of polyethylene oxide added (a + c in formula (3)) are not particularly limited, and may be used under conditions of use, purpose, etc. It can be selected as appropriate. The higher the proportion of polypropylene oxide blocks, the higher the affinity with rubber, and the slower the rate of migration to the rubber surface tends to be.

The degree of polymerization of the polypropylene oxide block (b in formula (3)) is preferably 10 or more, more preferably 20 or more, and preferably 20 or more, because the bloom of the nonionic surfactant can be preferably controlled. Is 100 or less, more preferably 60 or less, still more preferably 40 or less.
For the same reason, the amount of polyethylene oxide added (a + c in the formula (3)) is preferably 5 or more, more preferably 15 or more, and preferably 90 or less, more preferably 50 or less, still more preferably 30. It is as follows.

Examples of the pluronic nonionic surfactant include the Pluronic series manufactured by BASF Japan Ltd., the New Pole PE series manufactured by Sanyo Chemical Industries, Ltd., and the ADEKA Pluronic L or F manufactured by Asahi Denka Kogyo Co., Ltd. Products such as series, Epan series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Pronon series manufactured by NOF Corporation, and Unilube can be used.

The SP value of the nonionic surfactant may be 9.0 or more, preferably 9.1 or more, more preferably 9.2 or more, and preferably 12 or less, more preferably 11. Below, it is more preferably 10.5 or less. Within the above range, the effect tends to be better obtained.

In the present specification, the SP value means a solubility parameter (Solubility Parameter) calculated by the Hoy method based on the structure of the compound. The Hoy method is, for example, K.K. L. Hoy "Table of Solubility Parameters", Solvent and Coatings Materials Research and Development Development, Union Carbites Corp. It is a calculation method described in (1985).

The content of the nonionic surfactant is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and further preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. Further, it is preferably 4 parts by mass or less, more preferably 2 parts by mass or less. Within the above range, the flexibility of the bleed layer on the tread surface is improved, and the effect tends to be better obtained.

The rubber composition may contain a solid resin (a resin in a solid state at room temperature (25 ° C.)).
The solid resin is not particularly limited as long as it is widely used in the tire industry. For example, styrene resin, C5 resin, C9 resin, terpene resin, rosin resin, Kumaron inden resin, p. -T-Butylphenol acetylene resin, acrylic resin and the like can be mentioned. These may be used alone or in combination of two or more. Of these, styrene-based resins are preferable.

The styrene-based resin is a polymer containing a styrene-based monomer as a constituent monomer, and examples thereof include a polymer obtained by polymerizing a styrene-based monomer as a main component (50% by mass or more). Specifically, styrene-based monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, A homopolymer obtained by independently polymerizing o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.), a copolymer obtained by copolymerizing two or more styrene-based monomers, and a styrene-based monomer. And a copolymer with another monomer copolymerizable therewith.

Other monomers include acrylonitrile such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylics and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, terpene compounds, and chloroprene. , Conjugate dienes such as butadiene isoprene, olefins such as 1-butene and 1-pentene; α, β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof; and the like can be exemplified. These may be used alone or in combination of two or more.

Styrene-based resins are α-methylstyrene-based resins (α-methylstyrene homopolymers, copolymers of α-methylstyrene and styrene, etc.) and styrene-based resins because the effects tend to be better. A copolymer of a monomer and a terpen compound is preferable. Further, the α-methylstyrene resin is more preferably a copolymer of α-methylstyrene and styrene.

Commercially available solid resin products include, for example, Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Toso Co., Ltd., Rutgers Chemicals Co., Ltd., BASF, Arizona Chemical Co., Ltd., and Nikko Chemical Co., Ltd. , Nippon Catalyst Co., Ltd., JXTG Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Co., Ltd., ExxonMobil Co., Ltd., CrayValley Co., Ltd. and the like can be used.

The softening point of the solid resin is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and preferably 160 ° C. or lower, more preferably 150 ° C. or lower. Within the above range, the effect tends to be better obtained.
The softening point is the temperature at which the sphere has fallen when the softening point defined in JIS K 6220-1: 2001 is measured by a ring-ball type softening point measuring device.

The content of the solid resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and preferably 60 parts by mass or less, based on 100 parts by mass of the rubber component. It is more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain a liquid plasticizer (a plasticizer in a liquid state at room temperature (25 ° C.)).
The liquid plasticizer is not particularly limited as long as it is widely used in the tire industry, and examples thereof include oils, liquid resins, and liquid diene polymers. These may be used alone or in combination of two or more. Of these, oil and liquid resin are preferable.

Examples of the oil include process oils, vegetable oils and fats, or mixtures thereof. Examples of the process oil include paraffin-based process oil, aroma-based process oil, naphthen-based process oil, mild extraction solvate (MES (mild extraction solutions)), and treated distillate aromatic extract (TDAE (treated distillate)). Aromatic extracts)) and the like can be used. Vegetable oils and fats include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pineapple, tall oil, corn oil, rice oil, beni flower oil, sesame oil, Examples thereof include olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil, and oleic acid-containing oil. These may be used alone or in combination of two or more. Of these, process oils are preferable, and aroma-based process oils are more preferable.

Examples of oils include Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H & R Co., Ltd., Toyokuni Seiyu Co., Ltd., Showa Shell Sekiyu Co., Ltd., Fuji Kosan Co., Ltd. And other products can be used.

As the liquid resin, for example, a low molecular weight substance of the above-mentioned solid resin can be used. Of these, liquid Kumaron indene resin is preferable.

The liquid kumaron indene resin is a polymer containing kumaron and indene as constituent monomers, and examples thereof include a liquid polymer obtained by polymerizing these as main components (50% by mass or more). Examples of the monomer component that may be contained in the skeleton other than kumaron and indene include styrene, α-methylstyrene, methylindene, vinyltoluene and the like.

As the liquid resin, for example, products such as Rutgers Chemicals and CrayValley can be used.

The softening point of the liquid resin is preferably 1 ° C. or higher, more preferably 5 ° C. or higher, and preferably 40 ° C. or lower, more preferably 30 ° C. or lower. Within the above range, the effect tends to be better obtained.

The content of the liquid plasticizer is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and preferably 60 parts by mass or less, more preferably 50 parts by mass or less, based on 100 parts by mass of the rubber component. Is. Within the above range, the effect tends to be better obtained.

The rubber composition may contain an inorganic filler other than silica. As a result, better wet grip performance can be obtained.
Examples of the inorganic filler include aluminum hydroxide, alumina, zirconium oxide, magnesium sulfate, aluminum silicate, potassium carbonate, silicon carbide and the like. These may be used alone or in combination of two or more. Of these, aluminum hydroxide and magnesium sulfate are preferable, and aluminum hydroxide is more preferable.

Nitrogen adsorption specific surface area of aluminum hydroxide _(N 2 SA) of preferably ^{5 m} 2 / g or more, more preferably ^{10 m} 2 / g or more, and preferably ^{60 m} 2 / g or less, more preferably ^{50 m} 2 / It is less than or equal to g. Within the above range, the effect tends to be better obtained.
The N ₂ SA of aluminum hydroxide is a value measured by the BET method according to ASTM D3037-81.

As the inorganic filler, for example, products such as Nabaltec and Fujifilm Wako Pure Chemical Industries, Ltd. can be used.

The content of the inorganic filler (content of the inorganic filler other than silica) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 50 parts by mass with respect to 100 parts by mass of the rubber component. Parts or less, more preferably 40 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain wax.
The wax is not particularly limited, and examples thereof include petroleum wax such as paraffin wax and microcrystalline wax; natural wax such as plant wax and animal wax; and synthetic wax such as a polymer 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 Shinko Kagaku Kogyo Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Kagaku Co., Ltd. can be used.

The content of the wax is preferably 0.7 parts by mass or more, more preferably 1.0 part by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass, based on 100 parts by mass of the rubber component. It is less than a part. Within the above range, the effect tends to be better obtained.

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

As the anti-aging agent, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., Ltd. and the like can be used.

The content of the anti-aging agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 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 8 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain fatty acids, preferably stearic acid.
As the stearic acid, conventionally known ones can be used, and for example, products such as NOF Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., and Chiba Fatty Acid Co., Ltd. can be used.

The content of fatty acid (preferably stearic acid) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. It is preferably 5 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain zinc oxide.
Conventionally known zinc oxide can be used. For example, products of Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., HakusuiTech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. 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. It is preferably 5 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain sulfur.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur, which are 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 Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Corporation, Flexis Co., Ltd., Nippon Inui Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd. can be used.

The sulfur content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1.5 parts by mass or more, based on 100 parts by mass of the rubber component. 1.1 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain a hybrid cross-linking agent. As a result, wear resistance can be further improved while maintaining good wet grip performance.
As the hybrid cross-linking agent, for example, 1,3-bis (citraconimidemethyl) benzene, a compound represented by the following formula (α), or the like can be used. These may be used alone or in combination of two or more.

(In the formula, A represents an alkylene group having 2 to 10 carbon atoms, and B ¹ and B ² represent monovalent organic groups containing a nitrogen atom, which are the same or different.)

The alkylene group (carbon number 2 to 10) of A is not particularly limited, and examples thereof include a linear group, a branched group, and a cyclic group. Among them, a linear alkylene group is preferable. The number of carbon atoms is preferably 4 to 8. Specific examples of the alkylene group include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, and a decamethylene group. Of these, a hexamethylene group is preferable.

The B ¹ and B ² are not particularly limited as long as they are monovalent organic groups containing a nitrogen atom, but those containing at least one aromatic ring are preferable, and NC (=) in which a carbon atom is bonded to a dithio group. More preferably, it contains a linking group represented by S)-. B ¹ and B ² may be the same or different, but are preferably the same.

Examples of the compound represented by the formula (α) include 1,2-bis (N, N'-dibenzylthiocarbamoyldithio) ethane and 1,3-bis (N, N'-dibenzylthiocarbamoyldithio). Propane, 1,4-bis (N, N'-dibenzylthiocarbamoyldithio) butane, 1,5-bis (N, N'-dibenzylthiocarbamoyldithio) pentane, 1,6-bis (N, N' -Dibenzylthiocarbamoyldithio) Hexane, 1,7-bis (N, N'-dibenzylthiocarbamoyldithio) heptane, 1,8-bis (N, N'-dibenzylthiocarbamoyldithio) octane, 1,9 -Bis (N, N'-dibenzylthiocarbamoyldithio) nonane, 1,10-bis (N, N'-dibenzylthiocarbamoyldithio) decane and the like can be mentioned. These may be used alone or in combination of two or more. Of these, 1,6-bis (N, N'-dibenzylthiocarbamoyldithio) hexane is preferable.

As the hybrid cross-linking agent, for example, a product such as LANXESS can be used.

The content of the hybrid cross-linking agent is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and preferably 4 parts by mass or less, more preferably more preferably, with respect to 100 parts by mass of the rubber component. It is 3 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain a vulcanization accelerator.
Examples of the sulfide accelerator include thiazole-based sulfide-based sulfide accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; tetramethylthiuram disulfide (TMTD). ), Tetrabenzyl thiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N) and other thiuram-based sulfide accelerators; N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl- 2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, etc. Sulfenamide-based sulfide accelerator; guanidine-based sulfide accelerators such as diphenylguanidine, dioltotrilguanidine, orthotrilbiguanidine can be mentioned. These may be used alone or in combination of two or more. Of these, sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, and thiuram-based vulcanization accelerators are preferable. Further, a thiuram-based vulcanization accelerator is more preferable because it functions as a scorch inhibitor for a mercapto-based silane coupling agent.

As the vulcanization accelerator, for example, products manufactured by Kawaguchi Chemical Industry Co., Ltd., Ouchi Shinko Chemical Co., Ltd., Sanshin Chemical Industry Co., Ltd., etc. can be used.

The content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass with respect to 100 parts by mass of the rubber component. Hereinafter, it is more preferably 6 parts by mass or less. Within the above range, the effect tends to be better obtained.

In addition to the above components, additives generally used in the tire industry, such as organic peroxides, may be further added to the rubber composition. 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 kneading each of the components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing if necessary.

As the kneading conditions, in the base kneading step of kneading additives other than the vulcanizing agent and the vulcanization accelerator, 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 the vulcanization accelerator, the kneading temperature is usually 120 ° C. or lower, preferably 80 to 110 ° C. Further, the composition obtained by kneading the vulcanizing agent and the vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190 ° C., preferably 150 to 185 ° C. for passenger car tires, and usually 130 to 160 ° C., preferably 135 to 155 ° C. for truck and bus tires. The vulcanization time is usually 5 to 15 minutes for passenger car tires and 25 to 60 minutes for truck and bus tires.

The rubber composition is used for tire treads. In the case of a tread composed of a cap tread and a base tread, it can be suitably used for a cap tread.

The tire of the present invention (pneumatic tire, etc.) is produced by a usual method using the above rubber composition. That is, the unvulcanized tire is produced by extruding the rubber composition according to the shape of the tread at the unvulcanized stage and molding the unvulcanized tire together with other tire members by a normal method on a tire molding machine. Form. A tire is obtained by heating and pressurizing this unvulcanized tire in a vulcanizer.

The tread of the tire may be composed of at least a part of the rubber composition, and may be entirely composed of the rubber composition.

The tire of the present invention is produced by a usual method using the above rubber composition.
That is, the unvulcanized tire is produced by extruding the rubber composition according to the shape of the tread at the unvulcanized stage and molding the unvulcanized tire together with other tire members by a normal method on a tire molding machine. Form. A tire is obtained by heating and pressurizing this unvulcanized tire in a vulcanizer.

The above tires (pneumatic tires, etc.) are passenger car tires; truck / bus tires; two-wheeled vehicle tires; high-performance tires; winter tires such as studless tires; run-flat tires having side reinforcing layers; sound absorbing members such as sponges. A tire with a sound absorbing member provided in the tire cavity; a tire having a sealing member provided inside the tire or inside the tire cavity with a sealant that can be sealed at the time of puncture; an electronic component such as a sensor or a wireless tag provided inside the tire or inside the tire cavity. It can be used for tires with electronic parts and the like, and is suitable for passenger car tires.

The present invention will be specifically described based on Examples, but the present invention is not limited thereto.

Hereinafter, various chemicals used in Examples and Comparative Examples will be collectively described.
<SBR1>
N9548 (E-SBR, oil spread (containing 37.5 parts by mass of oil with respect to 100 parts by mass of rubber solids), styrene amount: 35% by mass, vinyl amount: 18% by mass, Tg, manufactured by Nippon Zeon Corporation : -40 ° C, Mw: 1.09 million)
<SBR2>
NS612 (S-SBR, non-oil-extended, styrene amount: 15% by mass, vinyl amount: 30% by mass, Tg: -65 ° C., Mw: 780,000) manufactured by Nippon Zeon Corporation.
<BR>
CB25 manufactured by LANXESS (BR (Nd-based BR) synthesized using an Nd-based catalyst, cis content: 97% by mass, vinyl content: 0.7% by mass, Tg: -110 ° C.)
<Carbon black>
Show Black N220 (N ₂ SA: 114m ² / g) manufactured by Cabot Japan Co., Ltd.
<Aluminum hydroxide>
Apyral 200SM (N ₂ SA: 15m ² / g) manufactured by Navaltec
<Silica 1>
Ultrasil VN3 manufactured by Evonik Degussa (N ₂ SA: 175m ² / g)
<Silica 2>
Z1085Gr manufactured by Solvay (N ₂ SA: 80m ² / g)
<Silica 3>
Ultrasil 9000GR (N ₂ SA: 240m ² / g) manufactured by Evonik Degussa
<Silane coupling agent 1>
Si75 (bis (3-triethoxysilylpropyl) disulfide, sulfur content: 14.4% by mass) manufactured by Evonik Degussa
<Silane coupling agent 2>
NXT-Z45 manufactured by Momentive (copolymer of binding unit A and binding unit B (bonding unit A: 55 mol%, binding unit B: 45 mol%), sulfur content: 3.3% by mass)
<Silane coupling agent 3>
Si363 manufactured by Evonik Degussa (silane coupling agent represented by the following formula, sulfur content: 3.2% by mass)

<Silane coupling agent 4>
NXT manufactured by Momentive (3-octanoylthiopropyltriethoxysilane, sulfur content: 8.8% by mass)
<Solid resin>
Sylvatraxx4401 manufactured by Arizona Chemical Co., Ltd. (copolymer of α-methylstyrene and styrene, softening point: 85 ° C.)
<Liquid resin>
Novares C10 (liquid kumaron indene resin, softening point: 10 ° C.) manufactured by Rutgers Chemicals.
<Amide compound>
WB16 manufactured by Structor (a mixture of fatty acid calcium, fatty acid amide and fatty acid amide ester)
<Surfactant>
Nieuport PE-64 (Pluronic nonionic surfactant (PEG / PPG-25 / 30 copolymer, a + c: 25, b: 30, SP value) of formula (3), manufactured by Sanyo Chemical Industries, Ltd. 2))
<Paraffin wax>
Ozoace0355 manufactured by Nippon Seiro Co., Ltd.
<Stearic acid>
Stearic acid "Camellia" manufactured by NOF CORPORATION
<Fatty acid zinc>
EF44 manufactured by Structor
<Oil>
Diana Process AH-24 (Aroma Process Oil) manufactured by Idemitsu Kosan Co., Ltd.
<Anti-aging agent 6PPD>
Lanxess Vulkanox 4020 (N-Phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine)
<Anti-aging agent TMQ>
Lanxess's Vulkanox HS (2,2,4-trimethyl-1,2-dihydroquinoline polymer)
<Zinc oxide>
2 types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. <Sulfur>
HK-200-5 manufactured by Hosoi Chemical Co., Ltd. (powdered sulfur containing 5% oil)
<Sulfenamide-based vulcanization accelerator>
Noxeller CZ (N-cyclohexyl-2-benzothiazolyl sulphenamide) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
<Thiuram-based vulcanization accelerator>
Suncella TBZTD (Tetrabenzyl Thiram Disulfide) manufactured by Sanshin Chemical Industry Co., Ltd.
<Hybrid cross-linking agent>
LANXESS Vulcuren VP KA9188 (1,6-bis (N, N'-dibenzylthiocarbamoyldithio) hexane)
<Guanidine-based vulcanization accelerator>
Noxeller D (diphenylguanidine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

(Examples and comparative examples)
According to the formulation shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than vulcanizing agents (sulfur, vulcanization accelerator, hybrid cross-linking agent) were used under the condition of 150 ° C. It was kneaded for 5 minutes to obtain a kneaded product. Next, a vulcanizing agent was added to the obtained kneaded product, and the mixture was kneaded under the condition of 80 ° C. for 5 minutes using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to form an unvulcanized tire, which is press-vulcanized for 12 minutes under the condition of 170 ° C. to obtain a test tire (test tire). Size: 195 / 65R15) was manufactured. The following evaluations were performed using the obtained test tires, and the results are shown in Table 1.

(Amount of sulfur after acetone extraction)
A test piece cut out from the tread of each test tire is set in a Soxhlet extractor, and acetone is used under the conditions of test piece: 10 g or less, acetone: 150 ml, constant temperature bath temperature: 95 to 100 ° C., and extraction time: 24-72 hours. Extraction was performed.
Then, the test piece after acetone extraction is placed in an oven and heated at 100 ° C. for 30 minutes to remove the solvent in the test piece, and then sulfur in the test piece is subjected to an oxygen combustion flask method based on JIS-K6233: 2016. The amount was calculated.

(Ash content)
The test pieces cut out from the tread of each test tire were placed in an alumina crucible and heated in an electric furnace at 550 ° C. for 4 hours. Then, the ash content (mass%) was calculated by (mass of test piece after heating / mass of test piece before heating) × 100.

(Abrasion resistance)
Each test tire is attached to all wheels of the vehicle (domestic FF2000cc), the groove depth of the tire tread after a mileage of 8000 km is measured, and the mileage when the tire groove depth is reduced by 1 mm is calculated and compared. It is expressed as an index when Example 1 is set to 100 (wear resistance index). The larger the index, the longer the mileage and the better the wear resistance. When the index was 110 or more, it was judged to be good.

(Wet grip performance)
Each test tire was attached to all wheels of the vehicle (domestic FF2000cc), the braking distance from the initial speed of 100km / h was obtained on a wet asphalt road surface, and it was displayed as an index when Comparative Example 1 was set to 100 (wet). Grip performance index). The larger the index, the shorter the braking distance and the better the wet grip performance. When the index was 100 or more, it was judged to be good.

From Table 1, an example including a tread containing a rubber component and a silane coupling agent and having a rubber composition having an ash content of 37% by mass or more and a sulfur content after acetone extraction of 0.75% by mass or less It was found that both the wear resistance and the wet grip performance exceeded the target values, and the total performance (average of the indexes) was also greatly improved.

Claims (9)

1. A tire comprising a rubber component and a silane coupling agent, and comprising a tread composed of a rubber composition having an ash content of 37% by mass or more and a sulfur content of 0.75% by mass or less after extraction with acetone.
2. The tire according to claim 1, wherein the amount of sulfur in the rubber composition is 0.65% by mass or less.
3. The tire according to claim 1 or 2, wherein in the rubber composition, the content of silica with respect to 100 parts by mass of the rubber component is 110 parts by mass or more.
4. The tire according to any one of claims 1 to 3, wherein the sulfur content of the silane coupling agent is 10% by mass or less.
5. The tire according to any one of claims 1 to 4, wherein the content of carbon black with respect to 100 parts by mass of the rubber component in the rubber composition is 10 parts by mass or less.
6. The rubber composition according to any one of claims 1 to 5, wherein the content of the amide compound or the nonionic surfactant having an SP value of 9.0 or more is 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component. The tires listed.
7. The tire according to any one of claims 1 to 6, wherein the rubber composition contains a thiuram-based vulcanization accelerator.
8. Any of claims 1 to 7, wherein the rubber composition comprises at least one inorganic filler selected from the group consisting of aluminum hydroxide, alumina, zirconium oxide, magnesium sulfate, aluminum silicate, potassium carbonate and silicon carbide. The tires listed in.
9. The tire according to any one of claims 1 to 8, wherein the rubber composition contains a solid resin.