JP7585657B2 - Rubber composition for tire inner layer member and tire - Google Patents

Description

The present invention relates to a rubber composition for tire inner layer components and a tire.

Various methods for improving fuel economy and durability have been studied (see, for example, Patent Documents 1 and 2). However, in recent years, there has been a demand for further improvement in the overall performance of these.

JP 2000-344955 A JP 2011-140532 A

The present invention aims to provide a rubber composition for tire inner layer components and a tire that can solve the above problems and improve the overall performance of fuel efficiency and durability.

The present invention relates to a rubber composition for tire inner layer members, which contains a rubber component containing isoprene-based rubber and a filler containing carbon black having a dibutyl phthalate oil absorption of 100 ml/100 g or more, the content of the filler is 35 to 55 parts by mass per 100 parts by mass of the rubber component, and the content of the carbon black is 70% by mass or more per 100% by mass of the filler.

Preferably, the filler comprises silica having a cetyltrimethylammonium bromide specific surface area of less than 180 m ² /g.

It is preferable that the nitrogen adsorption specific surface area of the carbon black/dibutyl phthalate oil absorption of the carbon black is less than 0.2.

It is preferable that the carbon black content is greater than the nitrogen adsorption specific surface area of the carbon black.

The rubber composition preferably contains a mercapto-based silane coupling agent.

The rubber composition preferably contains a dibenzylamine compound.

The rubber composition preferably contains a caprolactam compound.

The present invention also relates to a tire having an inner layer member made of the rubber composition.

The present invention is a rubber composition for tire inner layer members that contains a rubber component that includes an isoprene-based rubber and a filler that includes carbon black having a dibutyl phthalate oil absorption of 100 ml/100 g or more, the content of the filler is 35 to 55 parts by mass per 100 parts by mass of the rubber component, and the content of the carbon black is 70% by mass or more in 100% by mass of the filler, resulting in good overall performance in terms of fuel economy and durability.

The rubber composition for tire inner layer members of the present invention contains a rubber component containing isoprene-based rubber and a filler containing carbon black having a dibutyl phthalate (DBP) oil absorption of 100 ml/100 g or more, the content of the filler per 100 parts by mass of the rubber component is 35 to 55 parts by mass, and the content of the carbon black in 100% by mass of the filler is 70% by mass or more.

The reason why the above-mentioned effects are obtained with the above-mentioned rubber composition is presumed to be as follows.
In the above rubber composition, it is believed that the carbon black having a DBP oil absorption of 100 ml/100 g or more enhances the interaction obtained from the isoprene-based rubber, thereby achieving the effects of reducing heat build-up and improving durability.
Furthermore, in the above rubber composition, by adjusting the amount of filler and the ratio of the above carbon black in the filler within a predetermined range, it is believed that the carbon black is well dispersed in the rubber component, and interaction between the rubber component containing an isoprene-based rubber and the above carbon black is more likely to occur.
It is believed that these effects lead to a favorable interaction between the rubber component and the carbon black, which enhances the effects of reducing heat build-up and improving durability, thereby significantly improving the overall performance in terms of fuel economy and durability.

The rubber composition contains a rubber component.
Here, the rubber component is a component that contributes to crosslinking, and generally has a weight average molecular weight (Mw) of 10,000 or more.

The weight average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more, and is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within the above range, the effect tends to be better.

In this specification, the weight average molecular weight (Mw) can be calculated based on the measured value obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation) and converted into standard polystyrene.

The total amount of styrene in the rubber component is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may be 0% by mass. If it is within the above range, the effect tends to be better.

Here, the total amount of styrene in the rubber component is the total content (unit: mass%) of the styrene moieties contained in the entire rubber component, and can be calculated by Σ (content of each rubber component x amount of styrene in each rubber component/100). For example, if 100% by mass of the rubber component contains 85% by mass of SBR with a styrene content of 40% by mass, 5% by mass of SBR with a styrene content of 25% by mass, and 10% by mass of BR with a styrene content of 0% by mass, the total amount of styrene in the rubber component is 35.25% by mass (=85 x 40/100 + 5 x 25/100 + 10 x 0/100).

The total vinyl content in the rubber component is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may be 0% by mass. If it is within the above range, the effect tends to be better.

Here, the total vinyl content in the rubber component is the total content (unit: mass%) of vinyl parts contained in the total rubber component, and can be calculated by Σ (content of each rubber component x vinyl content in each rubber component/100). For example, if 100 mass% of the rubber component contains 85 mass% SBR with a vinyl content of 30 mass%, 5 mass% SBR with a vinyl content of 20 mass%, and 10 mass% BR with a vinyl content of 10 mass%, the total vinyl content in the rubber component is 27.5 mass% (=85 x 30/100 + 5 x 20/100 + 10 x 10/100).

The styrene content and vinyl content in each rubber component can be measured by a nuclear magnetic resonance (NMR) method.
In addition, in the examples of this specification, the total styrene amount and the total vinyl amount in the rubber component are calculated according to the above-mentioned formula, but they may be analyzed from the tire using, for example, a pyrolysis gas chromatograph mass spectrometer (Py-GC/MS) or the like.

The rubber composition contains an isoprene-based rubber as a rubber component.
Examples of isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. Examples of NR include SIR20, RSS#3, TSR20, and other rubbers that are common in the tire industry. Examples of IR include, but are not limited to, IR2200 and other rubbers that are common in the tire industry. Examples of modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), and other rubbers. Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more. Among these, NR is preferred.

The content of isoprene-based rubber in 100% by mass of the rubber component is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass. If it is within the above range, the effect tends to be better.

Other than isoprene-based rubber, other usable rubber components include diene-based rubbers such as styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). These may be used alone or in combination of two or more. Of these, SBR and BR are preferred.

There are no particular limitations on the SBR, and examples that can be used include emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR). Commercially available products include those from Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Co., Ltd.

The amount of SBR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. Within the above range, the effect tends to be better.

The BR is not particularly limited, and BR with a high cis content, BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. Commercially available products include those from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, etc.

The BR content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. Within the above range, the effect tends to be better obtained.

The rubber component may be modified to introduce a functional group that interacts with a filler such as silica.
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, a disulfide 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. These functional groups may have a substituent. Among them, an amino group (preferably an amino group in which a hydrogen atom of an amino group is substituted 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 alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

Specific examples of compounds (modifiers) having the above functional groups include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc.

The rubber composition contains, as a filler, carbon black having a dibutyl phthalate (DBP) oil absorption of 100 ml/100 g or more.
Examples of the carbon black include N134, N110, N220, N234, N339, N330, N351, and N550. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Shin-Nichika Carbon Co., Ltd., Columbia Carbon Co., Ltd., and the like. These may be used alone or in combination of two or more kinds.

The DBP oil absorption of the carbon black may be 100 ml/100 g or more, but is preferably 120 m ² /g or more, more preferably 130 m ² /g or more, even more preferably 140 m ^{2 /g or more, and is preferably 180 m 2 /} g or less, more preferably 160 m ² /g or less, even more preferably 150 m ² /g or less. Within the above ranges, the effect tends to be better.
The DBP oil absorption of carbon black can be measured in accordance with JIS-K6217-4:2001.

The nitrogen adsorption specific surface area ( _N2SA ) of the carbon black is preferably 5 ^m2 /g or more, more preferably 15 ^m2 /g or more, and even more preferably 20 ^m2 /g or more, and is preferably 85 ^m2 /g or less, more preferably 65 ^m2 /g or less, even more preferably 45 ^m2 /g or less, and particularly preferably 30 ^m2 /g or less. Within the above ranges, the effect tends to be better obtained.
The N ₂ SA of carbon black is a value measured in accordance with JIS K6217-2:2001.

The _N2SA of the carbon black/DBP oil absorption of the carbon black is preferably less than 0.8, more preferably less than 0.5, and even more preferably less than 0.2, and is preferably 0.1 or more. When it is within the above range, the effect tends to be better.

The amount of carbon black is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 25 parts by mass or more, and particularly preferably 30 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 60 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 35 parts by mass or less. Within the above range, the effect tends to be better obtained.

From the viewpoint of overall performance such as fuel economy and durability, it is preferable that the rubber composition satisfy the relationship: the content (unit: parts by mass) of the carbon black>the N ₂ SA of the carbon black.

The carbon black content/ _N2SA of the carbon black is preferably 1.1 or more, more preferably 1.2 or more, and is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.6 or less. Within the above ranges, the effect tends to be better.

The content of the carbon black in 100% by mass of the filler may be 70% by mass or more, but is preferably 75% by mass or more, and is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. If it is within the above range, the effect tends to be better.

Other than the carbon black, fillers that can be used include those commonly used in the tire industry, such as silica, calcium compounds, aluminum hydroxide, talc, mica, magnesium oxide, and magnesium sulfate. Carbon blacks other than the carbon blacks mentioned above (carbon blacks with DBP oil absorption of less than 100 ml/100 g) can also be used. These may be used alone or in combination of two or more. Of these, silica and calcium compounds are preferred.

Examples of silica include dry-process silica (anhydrous silicic acid) and wet-process silica (hydrated silicic acid). Wet-process silica is preferred because it has a large number of silanol groups. Commercially available products include those from EVONIK, Tosoh Silica, Solvay Japan, and Tokuyama. These may be used alone or in combination of two or more.

The cetyltrimethylammonium bromide (CTAB) specific surface area of the silica is preferably less than 180 m ² /g, more preferably 170 m ² /g or less, and is preferably 100 m ² /g or more, preferably 130 m ² /g or more, more preferably 150 m ² /g or more. Within the above range, the effect tends to be better.
The CTAB specific surface area of silica is measured in accordance with ASTM D3765-92.

The silica content is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. Within the above range, the effect tends to be better obtained.

Calcium compounds are compounds containing calcium, and examples of such compounds include inorganic salts such as calcium oxide, calcium hydroxide, and calcium carbide; and oxoacid salts such as calcium carbonate, calcium nitrate, and calcium sulfate. Oxoacid salts also include fatty acid salts such as calcium acetate and calcium stearate. Examples of compounds containing calcium compounds include eggshells (main component: calcium carbonate) and WB16 (a mixture of calcium fatty acid, fatty acid amide, and fatty acid amide ester) manufactured by Struktol. These compounds may be used alone or in combination of two or more. Of these, oxoacid salts are preferred, and calcium carbonate is more preferred.

In the above rubber composition, the content of the calcium compound is, in terms of calcium element, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more per 100 parts by mass of the rubber component, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less. Within the above ranges, the effect tends to be better obtained.

The amount of filler contained may be 35 to 55 parts by mass per 100 parts by mass of the rubber component, but is preferably 40 parts by mass or more, and is preferably 50 parts by mass or less, and more preferably 45 parts by mass or less. If it is within the above range, the effect tends to be better.

The rubber composition preferably contains a silane coupling agent.
The silane coupling agent is not particularly limited, and examples thereof include 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, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. As commercially available products, for example, products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., Toray Dow Corning Co., Ltd., etc. can be used. These may be used alone or in combination of two or more. Among them, mercapto-based ones are preferred.

In addition to compounds having a mercapto group, compounds having a structure in which the mercapto group is protected by a protecting group (for example, a compound represented by the following formula (S1)) can also be used as mercapto-based silane coupling agents.

（式中、Ｒ^１００１は－Ｃｌ、－Ｂｒ、－ＯＲ^１００６、－Ｏ（Ｏ＝）ＣＲ^１００６、－ＯＮ＝ＣＲ^１００６Ｒ^１００７、－ＮＲ^１００６Ｒ^１００７及び－（ＯＳｉＲ^１００６Ｒ^１００７）_ｈ（ＯＳｉＲ^１００６Ｒ^１００７Ｒ^１００８）から選択される一価の基（Ｒ^１００６、Ｒ^１００７及びＲ^１００８は同一でも異なっていても良く、各々水素原子又は炭素数１～１８の一価の炭化水素基であり、ｈは平均値が１～４である。）であり、Ｒ^１００２はＲ^１００１、水素原子又は炭素数１～１８の一価の炭化水素基、Ｒ^１００３は－［Ｏ（Ｒ^１００９Ｏ）_ｊ］－基（Ｒ^１００９は炭素数１～１８のアルキレン基、ｊは１～４の整数である。）、Ｒ^１００４は炭素数１～１８の二価の炭化水素基、Ｒ^１００５は炭素数１～１８の一価の炭化水素基を示し、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。）

（式中、ｖは０以上の整数、ｗは１以上の整数である。Ｒ^１１は水素、ハロゲン、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、分岐若しくは非分岐の炭素数２～３０のアルキニル基、又は該アルキル基の末端の水素が水酸基若しくはカルボキシル基で置換されたものを示す。Ｒ^１２は分岐若しくは非分岐の炭素数１～３０のアルキレン基、分岐若しくは非分岐の炭素数２～３０のアルケニレン基、又は分岐若しくは非分岐の炭素数２～３０のアルキニレン基を示す。Ｒ^１１とＲ^１２とで環構造を形成してもよい。） Particularly suitable mercapto-based silane coupling agents include silane coupling agents represented by the following formula (S1) and silane coupling agents containing a bond unit A represented by the following formula (I) and a bond unit B represented by the following formula (II).

(In the formula, R ¹⁰⁰¹ is a monovalent group selected from -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 ) (R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ may be the same or different, each is a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and 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, 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, R ¹⁰⁰⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, 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 the formula, v is an integer of 0 or more, and w is an integer of 1 or more. R ¹¹ represents hydrogen, halogen, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group having 2 to 30 carbon atoms, or an alkyl group in which the terminal hydrogen atom is substituted with a hydroxyl group or a carboxyl group. R ¹² represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms. R ¹¹ and R ¹² may form a ring structure.)

In formula (S1), R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ are each preferably independently a group selected from the group consisting of a linear, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group having 1 to 18 carbon atoms. When R ¹⁰⁰² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is preferably a group selected from the group consisting of a linear, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group. R ¹⁰⁰⁹ is preferably a linear, cyclic or branched alkylene group, particularly preferably a linear one. Examples of R ¹⁰⁰⁴ include 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, an arylene group having 6 to 18 carbon atoms, and an aralkylene group having 7 to 18 carbon atoms. The alkylene group and the alkenylene group may be either linear or branched, and the cycloalkylene group, the cycloalkylalkylene group, the arylene group, and the aralkylene group may have a functional group such as a lower alkyl group on the ring. R ¹⁰⁰⁴ is preferably an alkylene group having 1 to 6 carbon atoms, and particularly preferably a linear alkylene group, such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group.

Specific examples of R ¹⁰⁰² , R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ in formula (S1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, a cyclopentyl group, a cyclohexyl group, a vinyl group, a propenyl group, an allyl group, a hexenyl group, an octenyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a benzyl group, a phenethyl group and a naphthylmethyl group.
Examples of R ¹⁰⁰⁹ in formula (S1) include linear alkylene groups such as a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and a hexylene group, and examples of branched alkylene groups such as an isopropylene group, an isobutylene group, and a 2-methylpropylene group.

Specific examples of silane coupling agents represented by formula (S1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane, and the like. These may be used alone or in combination of two or more. Of these, 3-octanoylthiopropyltriethoxysilane is particularly preferred.

In the silane coupling agent comprising the bond unit A represented by formula (I) and the bond unit B represented by formula (II), the content of the bond unit A is preferably 30 mol% or more, more preferably 50 mol% or more, and preferably 99 mol% or less, more preferably 90 mol% or less.The content of the bond unit B is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and preferably 70 mol% or less, more preferably 65 mol% or less, even more preferably 55 mol% or less.The total content of the bond units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%.
The content of the bond units A and B includes the case where the bond units A and B are located at the terminals of the silane coupling agent. When the bond units A and B are located at the terminals of the silane coupling agent, the form of the bond units A and B is not particularly limited, and it is sufficient that the bond units A and B form units corresponding to the formulas (I) and (II) shown in FIG.

With respect to R ¹¹ in formulae (I) and (II), examples of halogen include chlorine, bromine, and fluorine. Examples of branched or unbranched alkyl groups having 1 to 30 carbon atoms include methyl and ethyl groups. Examples of branched or unbranched alkenyl groups having 2 to 30 carbon atoms include vinyl and 1-propenyl groups. Examples of branched or unbranched alkynyl groups having 2 to 30 carbon atoms include ethynyl and propynyl groups.

With respect to R ¹² in formulae (I) and (II), examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms include an ethylene group, a propylene group, etc. Examples of the branched or unbranched alkenylene group having 2 to 30 carbon atoms include a vinylene group, a 1-propenylene group, etc. Examples of the branched or unbranched alkynylene group having 2 to 30 carbon atoms include an ethynylene group, a propynylene group, etc.

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

The content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, and even more preferably 8 parts by mass or more, relative to 100 parts by mass of silica, and is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less. Within the above range, the effect tends to be better.

The rubber composition preferably contains a dibenzylamine compound.
The dibenzylamine compound is a compound having at least one group (dibenzylamine group) represented by the following formula:

Specific examples of dibenzylamine compounds include dibenzylamine, tetrabenzylthiuram disulfide (TBzTD), zinc dibenzyldithiocarbamate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, etc. Commercially available products include those from Sanshin Chemical Industry Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., LANXESS, etc. These may be used alone or in combination of two or more. Among these, compounds having two dibenzylamine groups are preferred, with 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane and tetrabenzylthiuram disulfide being more preferred, and 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane being even more preferred.

The content of the dibenzylamine compound is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 4 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1 part by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition preferably contains a caprolactam compound.
Examples of the caprolactam compound include N,N'-di(δ-caprolactam) disulfide, N,N'-di(ε-caprolactam) disulfide, N,N'-di(3-methyl-δ-caprolactam) disulfide, N,N'-di(3-ethyl-ε-caprolactam) disulfide, N,N'-di(3-isopropyl-ε-caprolactam) disulfide, and N,N'-di( Examples of the commercially available products include N,N'-di(3-ethoxy-ε-caprolactam) disulfide, N,N'-di(3-chloro-ε-caprolactam) disulfide, N,N'-di(δ-nitro-ε-caprolactam) disulfide, N,N'-di(3-amino-ε-caprolactam) disulfide, and dithiodicarolactam. As commercially available products, products from Rhein Chemie and the like can be used. These may be used alone or in combination of two or more. Among them, N,N'-di(ε-caprolactam) disulfide is preferred.

The content of the caprolactam compound is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the rubber component, and is preferably 6 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 2 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition contains a resin.
Examples of the resin include aromatic resins and terpene resins. These may be used alone or in combination of two or more. Among these, aromatic resins are preferred.

Aromatic resins are polymers that contain aromatic monomers as constituent monomers, and examples of such resins include homopolymers in which one type of aromatic monomer is polymerized alone, copolymers in which two or more types of aromatic monomers are copolymerized, and copolymers of aromatic monomers and other monomers that can be copolymerized with them.

Examples of aromatic monomers include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene; phenol monomers such as phenol, alkylphenol, and alkoxyphenol; naphthol monomers such as naphthol, alkylnaphthol, and alkoxynaphthol; coumarone, indene, and the like. These may be used alone or in combination of two or more.

The aromatic resin is preferably a phenolic resin, since this tends to produce better effects.
Examples of phenolic resins include phenolaldehyde condensation resins obtained by reacting a phenolic monomer with an aldehyde such as formaldehyde, acetaldehyde, or furfural using an acid or alkali catalyst, phenolalkyne condensation resins obtained by reacting a phenolic monomer with an alkyne such as acetylene, modified phenolic resins obtained by modifying these resins with a compound such as cashew oil, etc. Among these, phenolaldehyde condensation resins are preferred, and alkylphenol-formaldehyde condensation resins are more preferred.

Commercially available examples of the above-mentioned resins include those from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., JXTG Nippon Oil & Energy Corporation, Arakawa Chemical Industries Co., Ltd., and Taoka Chemical Co., Ltd.

The resin content (the total content when multiple types of resins are used) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. Within the above range, the effect tends to be better obtained.

In the rubber composition, the resin content/silica content is preferably 0.1 or more, and is preferably 0.8 or less, more preferably 0.6 or less, and further preferably 0.4 or less. Within the above range, the effect tends to be better obtained.
In this relationship, the resin content and the silica content are amounts (unit: parts by mass) based on 100 parts by mass of the rubber component.

In the rubber composition, the ratio of the resin content to the carbon black content having a DBP oil absorption of 100 ml/100 g or more is preferably 0.01 or more, more preferably 0.05 or more, and is preferably 0.50 or less, more preferably 0.30 or less, and even more preferably 0.20 or less. Within the above ranges, the effect tends to be better obtained.
In this regard, the resin content and the carbon black content are the contents (unit: parts by mass) relative to 100 parts by mass of the rubber component.

The rubber composition may contain oil.
Examples of the oil include process oil, vegetable oil, and mixtures thereof. Examples of the process oil include paraffin-based process oil, aromatic process oil, and naphthenic process oil. Examples of the vegetable oil include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. Examples of commercially available products include products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., JXTG Energy Corporation, Orisoi Co., Ltd., H&R Co., Ltd., Toyokuni Oil Mill Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., and the like. These may be used alone or in combination of two or more.

The oil content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 6 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above range, the effect tends to be better obtained.

The rubber composition may contain an antioxidant.
Examples of the antioxidant include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants 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, and N,N'-di-2-naphthyl-p-phenylenediamine. Examples of the antioxidant include p-phenylenediamine antioxidants such as quinolinone, quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline, monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Commercially available products include those of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd. These may be used alone or in combination of two or more.

The content of the anti-aging agent is preferably 1 part by mass or more, more preferably 4 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 12 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 9 parts by mass or less. Within the above range, the effect tends to be better.

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 vegetable wax and animal wax; and synthetic waxes such as polymers of ethylene, propylene, etc. Commercially available products include those from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. These may be used alone or in combination of two or more kinds.

The wax content is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component. Within the above range, the effect tends to be better.

The rubber composition may contain stearic acid.
As the stearic acid, a conventionally known one can be used, and as a commercially available product, a product from NOF Corp., Kao Corp., Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. can be used. These may be used alone or in combination of two or more kinds.

The content of stearic acid is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component. Within the above range, the effect tends to be better obtained.

The rubber composition may contain zinc oxide.
As the zinc oxide, a conventionally known one can be used, and as a commercially available product, there can be used products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more kinds.

The content of zinc oxide is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 4 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 10 parts by mass or less, and more preferably 6 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, soluble sulfur, etc., which are commonly used in the rubber industry. Commercially available products include those from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more.

The sulfur content is preferably 1.5 parts by mass or more, more preferably 2.5 parts by mass or more, and even more preferably 3.5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 8 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 5 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 vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD) and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolylguanidine, and orthotolylbiguanidine. Commercially available products include products from Sumitomo Chemical Co., Ltd. and Ouchi Shinko Chemical Co., Ltd. These may be used alone or in combination of two or more.

The content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and is preferably 8 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 4 parts by mass or less, per 100 parts by mass of the rubber component. If it is within the above range, the effect tends to be better.

The rubber composition may further contain additives commonly used in the tire industry, such as organic peroxides, in addition to the above components. The content of these additives is preferably 0.1 to 200 parts by mass per 100 parts by mass of the rubber component.

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

As for kneading conditions, in the base kneading process where additives other than the vulcanizing agent and vulcanization accelerator are kneaded, the kneading temperature is usually 100 to 180°C, preferably 120 to 170°C. In the finish kneading process where the vulcanizing agent and vulcanization accelerator are kneaded, the kneading temperature is usually 120°C or lower, preferably 85 to 110°C. Furthermore, the composition kneaded with the vulcanizing agent and 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. The vulcanization time is usually 5 to 15 minutes.

The rubber composition is used for tire inner layer components. Examples of tire inner layer components include base tread, breaker cushion, inner sidewall, inner liner, bead apex, and side reinforcing layer (insert) of run-flat tires, with base tread, breaker cushion, and side reinforcing layer being preferred.

The tire of the present invention is produced by a conventional method using the above rubber composition.
That is, the rubber composition is extruded in an unvulcanized state to match the shape of a desired tire inner layer component, and molded together with other tire components in a tire building machine by a normal method to form an unvulcanized tire. The unvulcanized tire is then heated and pressurized in a vulcanizer to obtain a tire.

The above-mentioned tires (pneumatic tires, etc.) can be used for passenger car tires; truck and bus tires; motorcycle tires; high-performance tires; winter tires such as studless tires; run-flat tires with side reinforcing layers; tires with sound absorbing materials that have sound absorbing materials such as sponge in the tire cavity; tires with sealing materials that have a sealant inside or in the tire cavity that can seal in the event of a puncture; tires with electronic components that have electronic components such as sensors and wireless tags inside or in the tire cavity, etc., and are suitable for passenger car tires and truck and bus tires.

The size of the above tires is not particularly limited, and can be appropriately selected, for example, the tire width within the range of 100 to 400 mm, the aspect ratio within the range of 25 to 85%, and the rim diameter within the range of 10 to 25 inches. Specific examples include 105/50R16, 115/50R17, 125/55R20, 135/45R21, 145/45R21, 155/45R18, 165/45R22, 175/45R23, 185/60R20, 195/55R14, 205/40R16, 215/40R16, 225/40R17, 235/40R17, 245/40R16, 255/40R17, 265/40R17, 275/35R18, 285/30R19, and 295/45R20.

なお、タイヤ外径（Ｄｔ）とは、タイヤを適用リムに装着して内圧２５０ｋＰａ・無負荷とした状態のタイヤの外径である。タイヤ断面幅（Ｗｔ）とは、タイヤを適用リムに装着して内圧２５０ｋＰａ・無負荷とした状態のタイヤ側面の模様又は文字など全てを含むサイドウォール間の直線距離、つまり総幅からタイヤの側面の模様、文字などを除いた幅である。 It is preferable that the tire outer diameter Dt and the tire section width Wt of the tire satisfy the following relational expression.

The tire outer diameter (Dt) is the outer diameter of the tire when mounted on an applicable rim and the internal pressure is 250 kPa with no load. The tire cross-sectional width (Wt) is the linear distance between the sidewalls including all patterns and letters on the tire side when mounted on an applicable rim and the internal pressure is 250 kPa with no load, that is, the width excluding the patterns and letters on the tire side from the total width.

Specific examples of tires that can satisfy the above formula include 145/60R18, 145/60R19, 155/55R18, 155/55R19, 155/70R17, 155/70R19, 165/55R20, 165/55R21, 165/60R19, 165/65R19, 165/70R18, 175/55R19, 175/55R20, 175/55R22, 175/60R18, 185/55R19, 185/60R20, 195/50R20, 195/55R20, etc.

Tires that satisfy the above formula are preferably used as pneumatic tires for passenger cars. This is because pneumatic tires for passenger cars that satisfy the above formula tend to be more suitable for solving the problem in question.

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

The various chemicals used in the examples and comparative examples are described below.

(Rubber component)
Natural rubber: TSR20
SBR: JSR1502 manufactured by JSR Corporation (styrene content: 24% by mass, vinyl content: 16% by mass)
BR: BR150B manufactured by Ube Industries, Ltd. (cis content: 97% by mass, vinyl content: 1% by mass)

(Chemicals other than rubber components)
Carbon black 1: Asahi #50U (N ₂ SA: 23 m ² /g, DBP: 63 ml/100 g) manufactured by Asahi Carbon Co., Ltd.
Carbon black 2: Diablack N330 (N ₂ SA: 79 m ² /g, DBP: 105 ml/100 g) manufactured by Mitsubishi Chemical Corporation
Carbon black 3: Niteron #SH SRF-HS (N ₂ SA: 24 m ² /g, DBP: 140 ml/100 g) manufactured by Nippon Steel Carbon Co., Ltd.
Calcium carbonate: Takehara Chemical Industry Co., Ltd.'s TANKAL #200 (calcium element content: about 40% by mass)
Silica: Ultrasil VN3 (CTAB: 165 m ² /g) manufactured by Evonik Degussa
Silane coupling agent 1: Si266 (bis(3-triethoxysilylpropyl)disulfide) manufactured by Evonik Degussa
Silane coupling agent 2: NXT (3-octanoylthiopropyltriethoxysilane) manufactured by Momentive
Resin: SP1068 (alkylphenol-formaldehyde condensation resin) manufactured by Nippon Shokubai Co., Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd.
Antioxidant 1: Nocrac 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Antioxidant 2: Nocrac RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Stearic acid: NOF Corporation's "Tsubaki" stearic acid
Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur vulcanization accelerator 1 manufactured by Tsurumi Chemical Industry Co., Ltd. Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Vulcanization accelerator 2: Noccela NS (N-tert-butyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Dibenzylamine compound 1: Vulcuren VP KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane) manufactured by LANXESS
Dibenzylamine compound 2: Sancerer TBzTD (tetrabenzyl thiuram disulfide) manufactured by Sanshin Chemical Industry Co., Ltd.
Vulcanization accelerator 3: Noccela TOT-N (tetrakis(2-ethylhexyl)thiuram disulfide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Caprolactam compound: Rhenogran CLD-80 (N,N'-di(ε-caprolactam) disulfide) manufactured by Rhein Chemie

Examples and Comparative Examples
According to the formulation shown in Table 1, materials other than the dibenzylamine compound, the caprolactam compound, the sulfur, and the vulcanization accelerator were kneaded for 5 minutes at 150°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. Next, the dibenzylamine compound, the caprolactam compound, the sulfur, and the vulcanization accelerator were added to the kneaded product obtained, and the mixture was kneaded for 5 minutes at 80°C using an open roll to obtain an unvulcanized rubber composition.
The obtained unvulcanized rubber composition was molded into the shape of a side reinforcing layer (insert), and laminated together with other tire components to form an unvulcanized tire. The unvulcanized tire was press-vulcanized for 12 minutes under a condition of 150°C to produce test tire 1 (run-flat tire, size: 195/55RF16).
In addition, the obtained unvulcanized rubber composition was molded into the shape of a base tread and a breaker cushion, and laminated together with other tire components to form an unvulcanized tire. The unvulcanized tire was press-vulcanized at 150° C. for 12 minutes to produce test tire 2 (size: 11R22.5).
The test tires 1 and 2 thus obtained were subjected to the following evaluations, and the results are shown in Table 1.

(low fuel consumption)
Using a rolling resistance tester, the rolling resistance was measured when the test tires 1 and 2 were run at a speed (80 km/h), and the rolling resistance was expressed as an index with the comparative example 4 being set at 100. A larger index indicates a smaller rolling resistance and better fuel economy.

(Durability 1 (Run-flat durability))
Test tire 1 was attached to all wheels of a domestically produced FF vehicle (2000cc), and with the valve core removed, the vehicle was driven around a test course at a speed of 120 km/h, and the distance traveled until the driver felt something was wrong was measured and expressed as an index, with Comparative Example 2 being set at 100. A larger index indicates a longer travel distance and better durability (run-flat durability).

(Durability 2)
Test tire 2 was fitted to all wheels of a domestically produced large truck, regular internal pressure was applied, the vehicle weight was adjusted so that the load per tire was 1.25 times the maximum load capacity, and the tire was driven around a test course at a speed of 80 km/h, and the running distance until damage such as cracks occurred was measured and expressed as an index, with Comparative Example 2 being set at 100. A higher index indicates a longer running distance and better durability.

As can be seen from Table 1, the examples were superior to the comparative examples in terms of the overall performance of the desired fuel economy and durability.

Claims (7)

The rubber composition contains a rubber component containing an isoprene-based rubber and a filler containing carbon black having a dibutyl phthalate oil absorption of 100 ml/100 g or more,
The amount of the filler per 100 parts by mass of the rubber component is 35 to 55 parts by mass,
The content of the carbon black is 70% by mass or more in 100% by mass of the filler,
the filler comprises silica having a cetyltrimethylammonium bromide specific surface area of less than 180 m ² /g;
the content of the carbon black is greater than the nitrogen adsorption specific surface area of the carbon black,
The rubber composition for a tire inner layer member is used for at least one selected from the group consisting of a base tread, a breaker cushion, an inner sidewall layer, an inner liner, a bead apex, and a side reinforcing layer of a run-flat tire. The rubber composition contains a rubber component containing an isoprene-based rubber and a filler containing carbon black having a dibutyl phthalate oil absorption of 100 ml/100 g or more,
The amount of the filler per 100 parts by mass of the rubber component is 35 to 55 parts by mass,
The content of the carbon black is 70% by mass or more in 100% by mass of the filler,
the filler comprises silica having a cetyltrimethylammonium bromide specific surface area of less than 180 m ² /g;
The rubber composition for a tire inner layer member, wherein the nitrogen adsorption specific surface area of the carbon black/the dibutyl phthalate oil absorption of the carbon black is less than 0.2. The rubber composition contains a rubber component containing an isoprene-based rubber and a filler containing carbon black having a dibutyl phthalate oil absorption of 100 ml/100 g or more,
The amount of the filler per 100 parts by mass of the rubber component is 35 to 55 parts by mass,
The content of the carbon black is 70% by mass or more in 100% by mass of the filler,
the filler comprises silica having a cetyltrimethylammonium bromide specific surface area of less than 180 m ² /g;
the nitrogen adsorption specific surface area of the carbon black/the dibutyl phthalate oil absorption amount of the carbon black is less than 0.2;
The rubber composition for a tire inner layer member is used for at least one selected from the group consisting of a base tread, a breaker cushion, an inner sidewall layer, an inner liner, a bead apex, and a side reinforcing layer of a run-flat tire . Contains mercapto-based silane coupling agent,
The mercapto-based silane coupling agent is
A compound having a mercapto group,
A silane coupling agent represented by the following formula (S1):

(In the formula, R ¹⁰⁰¹ is a monovalent group selected from -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 ) (R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ may be the same or different, each is a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and 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, 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, R ¹⁰⁰⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, 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.)
And,
A silane coupling agent comprising a bonding unit A represented by the following formula (I) and a bonding unit B represented by the following formula (II):

(In the formula, v is an integer of 0 or more, and w is an integer of 1 or more. R ¹¹ represents hydrogen, halogen, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group having 2 to 30 carbon atoms, or an alkyl group in which the terminal hydrogen atom is substituted with a hydroxyl group or a carboxyl group. R ¹² represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms. R ¹¹ and R ¹² may form a ring structure.)
The rubber composition for a tire inner layer member according to any one of claims 1 to 3 , which is at least one selected from the group consisting of: The rubber composition for a tire inner layer member according to any one of claims 1 to 4 , further comprising a dibenzylamine compound. The rubber composition for a tire inner layer member according to any one of claims 1 to 5 , further comprising a caprolactam compound. A tire having an inner layer member using the rubber composition according to any one of claims 1 to 6 .