tire

Abstract

To provide a tire having excellent wet grip performance during running at a high speed.SOLUTION: A tire comprises a tread. The tread comprises a layer composed of rubber compositions that include rubber components in which total contents of styrene-butadiene rubber, in which contents of isoprene rubber and butadiene rubber as well as styrene are 30 mass% or less and contents of vinyl are 30 mass% or less, are 90 mass% or more and silica, in which tanδ at 0°C is 0.50 or more, extracted volumes of acetone are 10.0 mass% or less, and densities are 1.30 g / cm3 or less, where a maximum thickness of the tread is 10.0 mm or less and an outer diameter of the tire is 700 mm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a tire. [Background technology]

[0002] As techniques for improving the wet grip performance of tires, methods that have been studied include blending silica into a tread rubber composition, increasing the blending amount of a low-softening point resin or a liquid polymer, blending a cold-resistant plasticizer, etc. However, in recent years, there has also been a demand for improvement in wet grip performance, particularly during high-speed driving. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to solve the above problems and to provide a tire that has excellent wet grip performance during high-speed running. [Means for solving the problem]

[0004] The present invention relates to a tire having a tread, The tread comprises a rubber component having a total content of 90% by mass or more of isoprene rubber, butadiene rubber, and styrene butadiene rubber having a styrene content of 30% by mass or less and a vinyl content of 30% by mass or less, and silica, and has a tan δ at 0°C of 0.50 or more, an acetone extractable content of 10.0% by mass or less, and a density of 1.30 g / cm 3 A layer made of the following rubber composition is provided: The tire has a maximum tread thickness of 10.0 mm or less and an outer diameter of 700 mm or less.

[0005] The tread preferably comprises a modified diene-based rubber and / or a functionalized resin having functional groups capable of reacting with silica.

[0006] The tread preferably contains 80 parts by mass or less of the silica per 100 parts by mass of the rubber component.

[0007] The tread preferably contains a mercapto-based silane coupling agent.

[0008] It is preferable that the contents of the isoprene-based rubber, the butadiene rubber, and the styrene-butadiene rubber in 100% by mass of the rubber component satisfy the following formula: [Isoprene rubber content / (butadiene rubber content + styrene butadiene rubber content)]≦0.50

[0009] The tread preferably contains the isoprene-based rubber, the butadiene rubber, and the styrene-butadiene rubber.

[0010] The functionalized resin preferably includes a functionalized resin having a functional group containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen.

[0011] In the tire, it is preferable that the acetone extractable amount and the maximum thickness of the tread satisfy the following formula: Acetone extractables x maximum tread thickness < 80

[0012] It is preferable that the acetone extractable amount and the tire outer diameter of the tire satisfy the following formula: Acetone extraction volume x tire outer diameter < 6500

[0013] In the tire, it is preferable that the tan δ at 0° C. and the maximum thickness of the tread satisfy the following formulas. (tan δ at 0°C / maximum tread thickness) x 1000>60.0

[0014] It is preferable that the tan δ at 0° C. and the tire outer diameter satisfy the following formulas. (tan δ at 0°C / tire outer diameter) x 1000>0.70 [Effects of the Invention]

[0015] According to the present invention, there is provided a tire having a tread, the tread comprising a rubber component having a total content of 90 mass % or more of isoprene rubber, butadiene rubber, and styrene butadiene rubber having a styrene content of 30 mass % or less and a vinyl content of 30 mass % or less, and silica, and having a tan δ at 0°C of 0.50 or more, an acetone extractable content of 10.0 mass % or less, and a density of 1.30 g / cm 3 The tire has a layer made of the rubber composition described below, and the maximum thickness of the tread is 10.0 mm or less, and the tire outer diameter is 700 mm or less, so that a pneumatic tire having excellent wet grip performance during high-speed running can be provided. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing a portion of a pneumatic tire. [Figure 2] 2 is an enlarged cross-sectional view showing the vicinity of the tread 4 of the tire 2 of FIG. 1. [Figure 3] FIG. 1 shows a synthetic route to end-capped silane-containing resins via phenol functionalization. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention provides a tire having a tread, the tread comprising a layer made of a rubber composition containing a rubber component having a total content of a predetermined isoprene-based rubber, a butadiene rubber (BR), a low-styrene content styrene-butadiene rubber (SBR), and a low-vinyl content styrene-butadiene rubber (SBR), and silica, and having a predetermined tan δ, acetone extractables, and density at 0°C, and further having a predetermined maximum tread thickness and tire outer diameter. The tire has excellent wet grip performance when running at high speeds.

[0018] The reason why such an effect is obtained is not clear, but is presumed to be as follows. A technology using silica has been proposed to reduce heat buildup. However, because silica is hydrophilic, it repels acetone-extractable components such as plasticizers, causing them to escape from the tread surface during driving and harden the rubber surface. This raises concerns about a decline in wet grip performance, particularly at high speeds, where centrifugal force increases, leading to more pronounced plasticizer exudation and a decline in wet grip performance. Therefore, by using isoprene-based rubber, BR, and low-styrene and low-vinyl-content SBR, which have low glass transition temperatures (Tg), as the main rubber components, the glass transition temperature of the rubber matrix can be lowered, resulting in a soft, grippy surface even at high frequencies (high speeds). Furthermore, when these three components are used, the interfaces between the polymer phases are incompatible or partially compatible, resulting in numerous interfaces, which is thought to hinder the movement of acetone-extractable components in particular. Furthermore, by setting the tan δ at 0°C to a predetermined value or higher, good wet grip performance can be obtained, and at the same time, by reducing the amount of acetone extractable components to a predetermined value or less, it is thought that the plasticizer is less likely to bleed out, thereby preventing a decrease in wet grip performance, particularly during high-speed driving. Furthermore, by reducing the maximum tread thickness, density, and tire outer diameter, it is thought that an increase in centrifugal force during driving is prevented, and at the same time, the contact shape is less likely to become unstable, thereby suppressing a decrease in wet grip performance during high-speed driving. From the above, it is presumed that the tire provides excellent wet grip performance during high-speed driving.

[0019] In this way, in a tire having a tread provided with a layer made of a rubber composition containing a rubber component having a total content of a predetermined isoprene-based rubber, BR, SBR with a low styrene content and a low vinyl content, and silica, "a tire having a tan δ at 0°C of 0.50 or more, an acetone extractable content of 10.0 mass% or less, a density of 1.30 g / cm 3 The objective of this tire is to provide excellent wet grip performance during high-speed driving by satisfying the following criteria: "a tan δ of 0.50 or more at 0°C, an acetone extractable content of 10.0 mass% or less, a density of 1.30 g / cm3 or less," "a maximum tread thickness of 10.0 mm or less," and "a tire outer diameter of 700 mm or less."3 The parameters "maximum tread thickness is 10.0 mm or less," "maximum tread thickness is 10.0 mm or less," and "tire outer diameter is 700 mm or less" do not define the problem (purpose); the problem of this application is to provide excellent wet grip performance during high-speed driving, and a configuration that satisfies these parameters is used as a means to achieve this.

[0020] The present invention will be described in detail below based on an example of a preferred embodiment with reference to the accompanying drawings as appropriate, but is not limited to this example.

[0021] Fig. 1 shows a pneumatic tire 2. In Fig. 1, the up-down direction is the radial direction of the tire 2, the left-right direction is the axial direction of the tire 2, and the direction perpendicular to the plane of the page is the circumferential direction of the tire 2. In Fig. 1, the dashed-dotted line CL represents the equatorial plane of the tire 2. The shape of this tire 2 is symmetrical with respect to the equatorial plane, except for the tread pattern.

[0022] The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of wings 8, a pair of clinches 10, a pair of beads 12, a carcass 14, a belt 16, a band 18, an inner liner 20, and a pair of chafers 22. The tire 2 is a tubeless type. The tire 2 is mounted on a passenger vehicle.

[0023] The tread 4 has a shape that is convex outward in the radial direction. The tread 4 forms a tread surface 24 that comes into contact with the road surface. Grooves 26 are cut into the tread 4. These grooves 26 form a tread pattern. The tread 4 has a base layer 28 and a cap layer 30. The cap layer 30 is located radially outward of the base layer 28. The cap layer 30 is laminated on the base layer 28.

[0024] Although FIG. 1 shows an example of a two-layer tread 4 made up of a cap layer 30 and a base layer 28, the tread 4 may have a single layer structure or a structure of three or more layers.

[0025] At least one of the rubber layers (layers of rubber composition after vulcanization) constituting the tread 4 contains a rubber component having a total content of 90 mass % or more of isoprene rubber, butadiene rubber, and styrene butadiene rubber having a styrene content of 30 mass % or less and a vinyl content of 30 mass % or less, and silica, and has a tan δ at 0°C of 0.50 or more, an acetone extractable content of 10.0 mass % or less, and a density of 1.30 g / cm 3 In the case of a single-layer tread, the tan δ at 0°C of the single-layer tread is 0.50 or more, the acetone extractable content is 10.0 mass% or less, and the density is 1.30 g / cm. In the case of a two-layer tread, the cap layer of the two-layer tread is 0.50 or more, and in the case of a tread having a three-layer or more layer structure, the cap layer (outermost layer) is 0.50 or more. 3 It is desirable that the following:

[0026] At least one of the rubber layers preferably has a tan δ (after vulcanization) at 0°C of 0.60 or more, more preferably 0.70 or more, and particularly preferably 0.80 or more. There is no particular upper limit, but it is preferably 1.50 or less, more preferably 1.30 or less. Within the above range, better effects tend to be obtained. The tan δ at 0° C. is the loss tangent measured under the conditions of a temperature of 0° C., an initial strain of 5%, a dynamic strain of 1%, a frequency of 10 Hz, and an extension mode.

[0027] Tan δ at 0°C can be adjusted, for example, by adjusting the amount of filler, SBR, or carbon black, by adding a liquid resin or liquid polymer, by adding silica or aluminum hydroxide, by adding a small particle size filler, by reducing the particle size of the filler, etc. Specifically, increasing the amount of filler, SBR, or carbon black, or adding a liquid resin, liquid polymer, silica, or aluminum hydroxide, or adding a small particle size filler tends to increase tan δ at 0°C.

[0028] At least one of the rubber layers preferably has an acetone extractable content (AE, after vulcanization) of 9.8% by mass or less, more preferably 9.6% by mass or less, and even more preferably 9.5% by mass or less. Although there is no particular lower limit, it is preferably 5.0% by mass or more, more preferably 6.0% by mass or more, and even more preferably 7.0% by mass or more. When it is within the above range, better effects tend to be obtained. The acetone extractables (AE) are measured by the method for measuring acetone extractables in accordance with JIS K 6229:2015.

[0029] The amount of acetone extractables can be adjusted by, for example, the amount of liquid plasticizer such as oil, the amount of antioxidant, the amount of processing aids, and the ratio of other components in the rubber composition. Specifically, the amount of acetone extractables tends to decrease when the amount of liquid plasticizer, antioxidant, or processing aid is reduced or when the amount of other components (fillers such as carbon black and silica) is increased.

[0030] At least one of the rubber layers has a density of 1.26 g / cm 3 Preferably less than 1.24 g / cm 3 Less than 1.22 g / cm is more preferable. 3 The lower limit is not particularly limited, but is preferably 1.00 g / cm 3 More than 1.05 g / cm is preferable. 3 More preferably, 1.10 g / cm or more 3 The above range is more preferable. When the amount is within the above range, the effect tends to be better. The density is calculated by measuring the mass in ethanol and the mass in air.

[0031] The density can be adjusted, for example, by the materials in the rubber composition (rubber components, fillers, etc.) Specifically, the density tends to decrease when a material with a low specific gravity is used or when the amount of plasticizer is increased.

[0032] At least one of the rubber layers constituting the tread 4 is made of a rubber composition for treads containing a rubber component and silica. It is preferable that the rubber composition for treads be made of the single-layer tread in the case of a single-layer tread, the cap layer of the two-layer tread in the case of a two-layer tread, or the cap layer (outermost layer) in the case of a tread having a structure of three or more layers.

[0033] The rubber component of the rubber composition for treads may be, for example, a diene rubber. Examples of diene rubber include isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Other examples include butyl rubber and fluororubber. These may be used alone or in combination of two or more.

[0034] The diene rubber may be an unmodified diene rubber or a modified diene rubber. The modified diene rubber may be any diene rubber having a functional group that interacts with a filler such as silica. For example, at least one end of the diene rubber is modified with a compound (modifier) ​​having the functional group (terminally modified diene rubber having the functional group at the end), main chain modified diene rubber having the functional group in the main chain, main chain terminal modified diene rubber having the functional group in the main chain and at least one end (for example, main chain terminal modified diene rubber having the functional group in the main chain and modified with the modifier), or terminal modified diene rubber modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and having a hydroxyl group or an epoxy group introduced therein. Among these, modified diene rubber having a functional group that can react with silica is preferred from the viewpoint of obtaining better effects.

[0035] The reason why such an effect is obtained is not clear, but is presumed to be as follows. It is believed that the modified diene rubber, which has functional groups that can react with silica, increases the number of polymer-silica networks, increasing the probability that the plasticizer will enter the network. This makes it harder for the plasticizer to seep out, preventing a decline in wet grip performance at high speeds and providing excellent wet grip performance at high speeds.

[0036] 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 imido 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 these, an amino group (preferably an amino group in which a hydrogen atom of the 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.

[0037] The rubber composition for treads has a total content of 90% by mass or more of isoprene-based rubber, BR, and SBR having a styrene content of 30% by mass or less and a vinyl content of 30% by mass or less, based on 100% by mass of the rubber component. The total content is preferably 93% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more, and may be 100% by mass. When the total content is within the above range, better effects tend to be obtained.

[0038] In order to obtain better effects, it is desirable that the content (mass%) of isoprene-based rubber in 100% by mass of the rubber component, the content (mass%) of butadiene rubber in 100% by mass of the rubber component, and the content (mass%) of styrene-butadiene rubber having a styrene content of 30% by mass or less and a vinyl content of 30% by mass or less in 100% by mass of the rubber component satisfy the following formula: [Isoprene rubber content / (butadiene rubber content + styrene butadiene rubber content with styrene content of 30% by mass or less and vinyl content of 30% by mass or less)] ≦ 0.80

[0039] The reason why such an effect is obtained is not clear, but is presumed to be as follows. Since isoprene-based rubber does not contain vinyl groups, it is difficult to react with silane coupling agents and to form a network with silica, which is thought to make it difficult to confine plasticizers within the rubber material. Therefore, by satisfying the above formula, the content of isoprene-based rubber is low, making it difficult for plasticizers to seep out, which is thought to prevent a decrease in wet grip performance at high speeds and provide excellent wet grip performance at high speeds.

[0040] [Isoprene rubber content / (butadiene rubber content+styrene butadiene rubber content having a styrene content of 30% by mass or less and a vinyl content of 30% by mass or less)] is preferably 0.70 or less, more preferably 0.64 or less, even more preferably 0.50 or less, and particularly preferably 0.30 or less. The lower limit is preferably 0.10 or more, more preferably 0.15 or more, and even more preferably 0.20 or more.

[0041] The rubber composition for treads has a total content of isoprene-based rubber, BR, and SBR having a styrene content of 30% by mass or less and a vinyl content of 30% by mass or less, which is equal to or more than a specified amount. From the viewpoint of obtaining better effects, however, a composition containing these three types of rubber components is preferred.

[0042] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. NRs such as SIR20, RSS#3, and TSR20 are commonly used in the rubber industry. IRs are not particularly limited, and examples of IRs such as IR2200 are commonly used in the rubber industry. Modified NRs include deproteinized natural rubber (DPNR) and highly purified natural rubber (UPNR). Modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0043] When the rubber composition for tread contains an isoprene-based rubber, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more. The upper limit is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 35% by mass or less. Within the above range, better effects tend to be obtained.

[0044] The BR is not particularly limited, and examples thereof include high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare earth catalyst (rare earth BR). These may be used alone or in combination of two or more. Among these, high-cis BR with a cis content of 90% by mass or more is preferred because it improves wear resistance.

[0045] The BR may be unmodified or modified. The modified BR may be a modified BR into which the same functional group as that of the modified diene rubber has been introduced.

[0046] When the rubber composition for tread contains BR, 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 even more preferably 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, and particularly preferably 20% by mass or less. Within the above range, the effect tends to be more favorably obtained.

[0047] As the BR, for example, products from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used.

[0048] The SBR is not particularly limited, and examples thereof include emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. These may be used alone or in combination of two or more.

[0049] The styrene content of the SBR is 30% by mass or less, preferably 28% by mass or less, more preferably 26% by mass or less, and even more preferably 25% by mass or less. There is no particular lower limit, but it is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more. Within the above range, better effects tend to be obtained. In this specification, the styrene content of SBR is 1 It is calculated by H-NMR measurement.

[0050] The vinyl content of the SBR is 30% by mass or less, preferably 28% by mass or less, more preferably 26% by mass or less, and even more preferably 25% by mass or less. There is no particular lower limit, but it is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more. The vinyl content (amount of 1,2-bonded butadiene units) can be measured by infrared absorption spectroscopy.

[0051] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., etc. can be used.

[0052] The SBR may be unmodified or modified, and the modified SBR may be modified SBR into which the same functional groups as those in modified diene rubbers have been introduced.

[0053] When the rubber composition for tread contains SBR, the content of SBR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 40% by mass or more. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, and particularly preferably 50% by mass or less. Within the above range, the effect tends to be more favorably obtained.

[0054] Examples of silica used in the rubber composition for tread include dry process silica (anhydrous silica), wet process silica (hydrated silica), etc. Among these, wet process silica is preferred because it has a large number of silanol groups.

[0055] In the rubber composition for treads, the content of silica is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 60 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit of the content is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, even more preferably 100 parts by mass or less, and particularly preferably 80 parts by mass or less. Within the above range, the effect tends to be more favorably obtained.

[0056] In particular, when the amount of silica is relatively small, such as 80 parts by mass or less, the effect is more favorable. The reason why such an effect is obtained is not clear, but is presumed to be as follows. Too much silica increases heat buildup and hydrophilicity, making it easier for acetone extractables to escape, but keeping the silica content at 80 parts by mass or less is thought to prevent the plasticizer from bleeding out, which is thought to prevent a decline in wet grip performance at high speeds and provide excellent wet grip performance at high speeds.

[0057] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 / g or more. The N2SA of the silica is preferably 250m 2 / g or less, more preferably 220m 2 / g or less, more preferably 200m 2 Within the above range, there is a tendency for the effect to be better obtained. The N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0058] As silica, for example, products from Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Corporation, etc. can be used.

[0059] The rubber composition for a tread preferably contains a silane coupling agent together with silica. The silane coupling agent is not particularly limited, and examples thereof include sulfide-based agents such as bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, and bis(3-trimethoxysilylpropyl)tetrasulfide, mercapto-based agents such as 3-mercaptopropyltrimethoxysilane, vinyl-based agents such as vinyltriethoxysilane, amino-based agents such as 3-aminopropyltriethoxysilane, glycidoxy-based agents such as γ-glycidoxypropyltriethoxysilane, nitro-based agents such as 3-nitropropyltrimethoxysilane, and chloro-based agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane.Among these, sulfide-based and mercapto-based agents are preferred, and mercapto-based agents are more preferred, from the viewpoint of obtaining better effects.

[0060] The reason why such an effect is obtained is not clear, but is presumed to be as follows. It is believed that increasing the reactivity of silica with a mercapto-based silane coupling agent improves silica dispersion and further reduces heat buildup. Furthermore, the silica becomes more hydrophobic, preventing the plasticizer, an acetone-extracted component, from repelling and escaping. This reduces the risk of plasticizer seepage, preventing a decline in wet grip performance at high speeds and providing excellent wet grip performance at high speeds.

[0061] As the mercapto-based silane coupling agent, in addition to a compound having a mercapto group, a compound 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.

[0062] Particularly suitable mercapto-based silane coupling agents include silane coupling agents represented by the following formula (S1) and silane coupling agents containing a bonding unit A represented by the following formula (I) and a bonding unit B represented by the following formula (II). [ka] (In the formula, R 1001 -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 (R 1006 , R 1007 and R 1008 may be the same or different, and each represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and h has an average value of 1 to 4; 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, and j is an integer of 1 to 4. 1004 is a divalent hydrocarbon group having 1 to 18 carbon atoms, R 1005 represents a monovalent hydrocarbon group having 1 to 18 carbon atoms, and x, y, and z are numbers that satisfy the relationships: x+y+2z=3, 0≦x≦3, 0≦y≦2, 0≦z≦1. [ka] [ka] (wherein v is an integer of 0 or more, and w is an integer of 1 or more. R 11 R 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 has been substituted with a hydroxyl group or a carboxyl group. 12represents 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. 11 and R 12 may form a ring structure with

[0063] In formula (S1), R 1005 , R 1006 , R 1007 and R 1008 are each independently a group selected from the group consisting of a linear, cyclic or branched alkyl group, an alkenyl group, an aryl group and an aralkyl group having 1 to 18 carbon atoms. 1002 When R 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, an alkenyl group, an aryl group, and an aralkyl group. 1009 R is preferably a linear, cyclic or branched alkylene group, and is particularly preferably a linear one. 1004 Examples of R include alkylene groups having 1 to 18 carbon atoms, alkenylene groups having 2 to 18 carbon atoms, cycloalkylene groups having 5 to 18 carbon atoms, cycloalkylalkylene groups having 6 to 18 carbon atoms, arylene groups having 6 to 18 carbon atoms, and aralkylene groups having 7 to 18 carbon atoms. The alkylene groups and alkenylene groups may be either linear or branched, and the cycloalkylene groups, cycloalkylalkylene groups, arylene groups, and aralkylene groups may have a functional group such as a lower alkyl group on the ring. 1004 As the alkylene group, an alkylene group having 1 to 6 carbon atoms is preferred, and a linear alkylene group such as a methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, or hexamethylene group is particularly preferred.

[0064] R in formula (S1) 1002 , R 1005 , R 1006 , R 1007 and R 1008Specific examples of the alkyl group 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. R in formula (S1) 1009 Examples of the linear alkylene group include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and a hexylene group, and examples of the branched alkylene group include an isopropylene group, an isobutylene group, and a 2-methylpropylene group.

[0065] Specific examples of the silane coupling agent 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, and 2-lauroylthioethyltrimethoxysilane. These may be used alone or in combination of two or more. Among these, 3-octanoylthiopropyltriethoxysilane is particularly preferred.

[0066] In the silane coupling agent containing 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, particularly preferably 100 mol%. The content of the bonding units A and B includes the case where the bonding units A and B are located at the terminals of the silane coupling agent. When the bonding units A and B are located at the terminals of the silane coupling agent, the form of the bonding units A and B is not particularly limited, as long as they form units corresponding to the formulas (I) and (II) representing the bonding units A and B.

[0067] R in formulas (I) and (II) 11 With respect to the above, 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.

[0068] R in formulas (I) and (II) 12 Regarding the above, examples of branched or unbranched alkylene groups having 1 to 30 carbon atoms include an ethylene group, a propylene group, etc. Examples of branched or unbranched alkenylene groups having 2 to 30 carbon atoms include a vinylene group, a 1-propenylene group, etc. Examples of branched or unbranched alkynylene groups having 2 to 30 carbon atoms include an ethynylene group, a propynylene group, etc.

[0069] 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 bonding unit A (v) and the bonding unit B (w) is preferably in the range of 3 to 300.

[0070] As the silane coupling agent, for example, products from Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., Dow Corning Toray Co., Ltd., etc. can be used.

[0071] In the rubber composition for treads, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 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 25 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 ranges, the effect tends to be more favorably obtained.

[0072] Fillers other than silica that can be used in the rubber composition for treads include those known in the rubber field, such as carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, mica, etc. Of these, carbon black is preferred.

[0073] Carbon black that can be used in the rubber composition for treads includes, but is not particularly limited to, GPF, FEF, HAF, ISAF, SAF, etc. Commercially available products that can be used include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin-Nichika Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc.

[0074] In the rubber composition for treads, the content of carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component. The content of carbon black is preferably 15 parts by mass or less, more preferably 10 parts by mass or less. Within the above range, better effects tend to be obtained.

[0075] In the rubber composition for tread, the nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 50 m 2 / g or more, more preferably 70m 2 / g or more, more preferably 85m 2 The upper limit of the N2SA of the carbon black is not particularly limited, but is preferably 150 m 2 / g or less, more preferably 130m 2 / g or less, more preferably 120m 2 Within the above range, there is a tendency for the effect to be better obtained. The nitrogen adsorption specific surface area of ​​carbon black can be determined by Method A of JIS K6217.

[0076] From the viewpoint of obtaining a better effect, the rubber composition for a tread desirably contains a functionalized resin as a plasticizer. As the functionalized resin, for example, a functionalized resin having a functional group containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen is suitable.

[0077] The reason why such an effect is obtained is not clear, but is presumed to be as follows. The incorporation of a functionalized resin is believed to bond the functionalized resin with the silica, thereby preventing the phenomenon in which the acetone-extractable plasticizer repels and escapes from the hydrophilic silica. This makes it difficult for the plasticizer to seep out, preventing a decline in wet grip performance at high speeds and providing excellent wet grip performance at high speeds.

[0078] The functional group containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen includes the functional groups described above that contain at least one element selected from the group consisting of oxygen, silicon, and nitrogen, as well as other known functional groups containing such elements. Among these, a group represented by -Si(R)3 (where R may be the same or different and may be hydrogen, an organic element-containing group, an inorganic element-containing group, an organic element and an inorganic element-containing group, etc.) is preferred.

[0079] The functionalized resin can be produced by a known method, for example, by a slurry method, a metathesis method, etc. Specifically, for example, the functionalized resin can be produced by reacting a polymer that serves as the polymer backbone of the functionalized resin with a functional compound that can introduce a functional group containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen, by a known method.

[0080] The polymer that forms the polymer backbone is not particularly limited and any polymer that can form a backbone can be used, and examples thereof include liquid resins (polymers that are liquid at 25°C) and solid resins (polymers that are solid at 25°C). Of these, solid resins are preferred. These polymers may be used alone or in combination of two or more.

[0081] The liquid resin is not particularly limited, but examples thereof include liquid aromatic vinyl polymers, coumarone-indene resins, indene resins, terpene resins, rosin resins, and hydrogenated products thereof. These may be used alone or in combination of two or more. Among these, liquid aromatic vinyl polymers are preferred.

[0082] Examples of liquid aromatic vinyl polymers include resins obtained by polymerizing α-methylstyrene and / or styrene, and specific examples include liquid resins such as a homopolymer of styrene, a homopolymer of α-methylstyrene, and a copolymer of α-methylstyrene and styrene.

[0083] Liquid coumarone-indene resins include resins containing coumarone and indene as the main monomer components constituting the resin skeleton (main chain), and examples of monomer components that may be contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0084] The liquid indene resin may be a liquid resin containing indene as a main monomer component that constitutes the skeleton (main chain) of the resin.

[0085] Examples of liquid terpene resins include resins obtained by polymerizing terpene compounds such as α-pinene, β-pinene, camphene, and dipentene, and liquid terpene resins typified by terpene phenol, which is a resin obtained from a terpene compound and a phenolic compound as raw materials.

[0086] Examples of liquid rosin resins include liquid rosin-based resins such as natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0087] The solid resin (resin that is solid at 25°C) is not particularly limited, and examples thereof include solid styrene-based resins, coumarone-indene resins, terpene-based resins, pt-butylphenol acetylene resins, acrylic resins, dicyclopentadiene-based resins (DCPD-based resins), C5-based petroleum resins, C9-based petroleum resins, and C5C9-based petroleum resins. These may be used alone or in combination of two or more. Of these, solid styrene-based resins are preferred.

[0088] The solid styrene-based resin is a solid polymer using a styrene-based monomer as a constituent monomer, and examples thereof include polymers obtained by polymerizing a styrene-based monomer as the main component (50% by mass or more).Specific examples include homopolymers obtained by polymerizing each of styrene-based monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) alone, copolymers obtained by copolymerizing two or more types of styrene-based monomers, and copolymers of a styrene-based monomer and another monomer copolymerizable therewith. Examples of other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene and 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.

[0089] The solid coumarone-indene resin may be a solid resin having the same structural units as the liquid coumarone-indene resin described above.

[0090] Examples of solid terpene resins include polyterpenes, terpene phenols, and aromatic-modified terpene resins. Examples of solid polyterpenes include terpene resins such as α-pinene resins, β-pinene resins, limonene resins, dipentene resins, and β-pinene / limonene resins made from terpene compounds, as well as solid resins such as hydrogenated terpene resins obtained by hydrogenating such terpene resins. Examples of solid terpene phenols include solid resins obtained by copolymerizing a terpene compound with a phenolic compound, and solid resins obtained by hydrogenating such resins, specifically solid resins obtained by condensing a terpene compound, a phenolic compound, and formalin. Examples of solid aromatic-modified terpene resins include solid resins obtained by modifying a terpene resin with an aromatic compound, and solid resins obtained by hydrogenating such resins.

[0091] The solid pt-butylphenol acetylene resin may be a solid resin obtained by subjecting pt-butylphenol and acetylene to a condensation reaction.

[0092] The solid acrylic resin is not particularly limited, and examples thereof include solvent-free acrylic solid resins. Examples of monomer components constituting the solid acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives. Furthermore, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used as monomer components constituting the solid acrylic resin, along with (meth)acrylic acid and (meth)acrylic acid derivatives. The solid acrylic resin may be a resin composed solely of (meth)acrylic components, or a resin containing components other than (meth)acrylic components. Furthermore, the solid acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0093] The softening point of the solid resin constituting the polymer skeleton is preferably 160° C. or lower, more preferably 130° C. or lower, even more preferably 110° C. or lower, and particularly preferably 96° C. or lower. The lower limit is preferably 60° C. or higher, more preferably 70° C. or higher, even more preferably 80° C. or higher, and particularly preferably 85° C. or higher. Within the above range, better effects tend to be obtained. In this specification, the softening point of a solid resin is the temperature at which the ball drops when the softening point specified in JIS K 6220-1:2001 is measured using a ring and ball softening point tester.

[0094] The functional compound can be any compound capable of introducing a functional group containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen, but among these, a compound capable of introducing a functional group containing silicon is preferred.

[0095] Suitable examples of the functional compound include compounds represented by the following formula:

[0096] [ka] (In the formula, p represents an integer of 1 to 1000. R 11 and R 12 R are the same or different and each represents a monovalent hydrocarbon group which may have a substituent. 13 are the same or different and each represents a monovalent hydrocarbon group which may have a substituent.

[0097] p is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more, and is preferably 800 or less, more preferably 700 or less, and even more preferably 600 or less.

[0098] R 11 , R 12 , R 13 The monovalent hydrocarbon group, which may have a substituent, preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. Examples of the monovalent hydrocarbon group, which may have a substituent, include substituted or unsubstituted alkyl groups and alkenyl groups. Examples of the alkyl group include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, sec-butyl groups, tert-butyl groups, phenyl groups, and fluoroalkane groups. Examples of the alkenyl group include vinyl groups, allyl groups, 1-propenyl groups, and 1-methylethenyl groups.

[0099] Suitable examples of the functional compound include compounds represented by the following formula: [ka] (In the formula, q represents an integer of 2 to 40. R 21 are the same or different and represent monovalent hydrocarbon groups which may have a substituent.

[0100] q is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, and is preferably 38 or less, more preferably 36 or less, and even more preferably 35 or less.

[0101] R 21 The monovalent hydrocarbon group, which may have a substituent, preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. R 21 Specific examples of R 11 , R 12 , R 13 Examples of the monovalent hydrocarbon group include those similar to the optionally substituted monovalent hydrocarbon groups of the above.

[0102] Suitable examples of the functional compound include compounds represented by the following formula:

[0103] [ka] (In the formula, X may be the same or different and represents a nitrogen, oxygen, or sulfur atom. Y may be the same or different and represents a boron, nitrogen, oxygen, silicon or sulfur atom. R 31 are the same or different and each represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group. R 32 are the same or different and each represents a divalent hydrocarbon group which may have a substituent. R 33 are the same or different and represent a hydrogen atom, a halogen atom, a sulfonate group, or a monovalent hydrocarbon group which may have a substituent. R 31 , R 31 and R 33 may be joined together to form a mononuclear or polynuclear ring. R 34 represents a monovalent hydrocarbon group which may have a substituent. a, b, and c are the same or different and represent integers, and a+b+c=3. X and Y are the same or different, and r=2 when Y is a boron atom, r=2 when X or Y is a nitrogen atom, r=1 when X or Y is an oxygen atom or a sulfur atom, and r=3 when Y is a silicon atom.

[0104] X may be the same or different and is a nitrogen atom, an oxygen atom, or a sulfur atom, with an oxygen atom being preferred.

[0105] Y may be the same or different and is a boron atom, nitrogen atom, oxygen atom, silicon atom, or sulfur atom, with an oxygen atom being preferred.

[0106] R 31 , R 33 , R 34 The monovalent hydrocarbon group, which may have a substituent, preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. R 31 , R 33 , R 34 Specific examples of R 11 , R 12 , R 13 Examples of the monovalent hydrocarbon group include those similar to the optionally substituted monovalent hydrocarbon groups of the above.

[0107] R 32 The divalent hydrocarbon group, which may have a substituent, preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. Examples of the divalent hydrocarbon group, which may have a substituent, include a substituted or unsubstituted alkylene group and arylene group. Examples of the alkylene group include a methylene group, an ethylene group, and a trimethylene group. Examples of the arylene group include a phenylene group, a naphthylene group, and a biphenylene group.

[0108] a, b, and c are the same or different and represent an integer of 0 to 3, and a+b+c=3.

[0109] Suitable examples of the functional compound include compounds represented by the following formula:

[0110] [ka] (In the formula, X may be the same or different and represents a nitrogen, oxygen, or sulfur atom. Y may be the same or different and represents a boron, nitrogen, oxygen, silicon, or sulfur atom. R 31 are the same or different and each represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group. R 32 are the same or different and each represents a divalent hydrocarbon group which may have a substituent. R 33 are the same or different and represent a hydrogen atom, a halogen atom, a sulfonate group, or a monovalent hydrocarbon group which may have a substituent. R 31 , R 31 and R 33 may be joined together to form a mononuclear or polynuclear ring. R 35 represents a divalent hydrocarbon group which may have a substituent. a, b, and c are the same or different and represent integers, and a+b+c=3. d, e, and f are the same or different and represent integers, and d+e+f=3. X and Y are the same or different, and r=2 when Y is a boron atom, r=2 when X or Y is a nitrogen atom, r=1 when X or Y is an oxygen atom or a sulfur atom, and r=3 when Y is a silicon atom.

[0111] X may be the same or different and is a nitrogen atom, an oxygen atom, or a sulfur atom, with an oxygen atom being preferred.

[0112] Y may be the same or different and is a boron atom, nitrogen atom, oxygen atom, silicon atom, or sulfur atom, with an oxygen atom being preferred.

[0113] R 31 , R 33 The monovalent hydrocarbon group, which may have a substituent, preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. R 31 , R 33 Specific examples of R 11 , R 12 , R 13 Examples of the monovalent hydrocarbon group include those similar to the optionally substituted monovalent hydrocarbon groups of the above.

[0114] R 32 , R 35 The optionally substituted divalent hydrocarbon group preferably has 1 to 20 carbon atoms. The number of carbon atoms is more preferably 2 or more, more preferably 14 or less, and even more preferably 12 or less. 32 , R 35 Specific examples of R 32 Examples of the divalent hydrocarbon group include those similar to the optionally substituted divalent hydrocarbon group of the above.

[0115] a, b, and c are the same or different and represent an integer of 0 to 3, and a+b+c=3. d, e, and f are the same or different and represent an integer of 0 to 3, and d+e+f=3.

[0116] Specific examples of the functional compound include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, allyltrimethoxysilane, allylmethyldimethoxysilane, allyldimethylmethoxysilane, allyltriethoxysilane, allylmethyldiethoxysilane, allyldimethylethoxysilane, hexenyltrimethoxysilane, hexenylmethyldimethoxysilane, hexenyldimethylmethoxysilane, and hexenyltriethoxysilane. Silane, hexenylmethyldiethoxysilane, hexenyldimethylethoxysilane, octenyltrimethoxysilane, octenylmethyldimethoxysilane, octenyldimethylmethoxysilane, octenyltriethoxysilane, octenylmethyldiethoxysilane, octenyldimethylethoxysilane, norbornenylethyltrimethoxysilane, norbornenylethylmethyldimethoxysilane, norbornenylethyldimethylmethoxysilane, norbornenylethyltriethoxysilane, norbornenylethylmethyldiethoxysilane, norbornenyl Nylethyldimethylethoxysilane, (meth)acryloxypropyltrimethoxysilane, (meth)acryloxypropylmethyldimethoxysilane, (meth)acryloxypropyldimethylmethoxysilane, (meth)acryloxypropyltriethoxysilane, (meth)acryloxypropylmethyldiethoxysilane, (meth)acryloxypropyldimethylethoxysilane, (meth)acryloxytrimethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxy Examples of suitable silanes include dimethyltriethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acryloxymethyldimethylethoxysilane, (meth)acryloxyoctyltrimethoxysilane, (meth)acryloxyoctylmethyldimethoxysilane, (meth)acryloxyoctyldimethylmethoxysilane, (meth)acryloxyoctyltriethoxysilane, (meth)acryloxyoctylmethyldiethoxysilane, and (meth)acryloxyoctyldimethylethoxysilane. Among these, vinyltrimethoxysilane,Examples include vinyltriethoxysilane and (meth)acryloxypropyltrimethoxysilane. Of these, allyltriethoxysilane is preferred.

[0117] The functionalized resin may also be a silane-functionalized resin having the general structure of formula (I) below: wherein "resin" represents the skeleton of the resin. Resin-[Z k -X n -R 1 -(CH2) m -Si(R 2 ) p ] q (I) (wherein Z is an aromatic or aliphatic group which may contain a heteroatom. X is a linker containing a heteroatom selected from sulfur, oxygen, nitrogen, a carbonyl group, or a combination thereof. R 1 is one or more aliphatic and / or aromatic C1-C 18 and / or a linking group containing a heteroatom. R 2 are C1 to C independently. 18 an alkoxy group, an aryloxy group, an alkyl group, an aryl group, or H or OH; 2 is C1~C 18 is an alkoxy group, an aryloxy group, or H or OH. q is an integer of at least one. k is an integer of 0 or 1. n is an integer from 1 to 10. m is an integer from 0 to 10. p is 1, 2, or 3.

[0118] Examples of Z include aromatic groups (such as six-membered aromatic groups), saturated or unsaturated alicyclic groups, etc. Examples of X include oxygen, a carbonyl group, and sulfur.

[0119] R 1 As an example, -O-CO-NH-R 3-(CH2)2-, -O-CO-R 3 -(CH2)2-, -O-CH2-R 3 -(CH2)2-, -CO-R 3 -(CH2)2-, -CO-NH-R 3 -(CH2)2-, or a mixture thereof. 3 Examples of the alkyl group include an aliphatic or aromatic C1 to C8 carbon chain which may contain a hetero atom, and preferably an aliphatic or aromatic C1 to C8 carbon chain.

[0120] n is preferably an integer of 1 to 9, more preferably 1 to 5, even more preferably 1 to 3, and particularly preferably 1 or 2. m is preferably an integer of 1 to 10, more preferably 4 to 10, even more preferably 8 to 10, and particularly preferably 9 to 10.

[0121] The silane-containing groups grafted onto the resin represented by formula (I) can be located at the termini of the polymer resin units (end caps), randomly distributed along the polymer backbone (at pendant positions within the polymer resin), or a combination thereof.

[0122] The amount of the silane-containing group grafted onto the resin represented by formula (I) is preferably 0.001 to 100 mol %, more preferably 0.1 to 50 mol %, even more preferably 0.1 to 30 mol %, and particularly preferably 0.1 to 25 mol %.

[0123] The resin represented by the formula (I) has one or more terminal functional groups -[Z k -X n -R 1 -(CH2) m -Si(R 2 ) p ] q The resin of formula (I) preferably comprises one or more (q) groups Z pendantly attached to the backbone of the resin in a random, segmented, or block structure. k -X n -R 1 -(CH2) m -Si(R 2 )p Other embodiments include an embodiment in which the side chains are end-capped, an embodiment in which the side chains are a mixture of end-capped and pendant.

[0124] Other suitable examples of the silane-functionalized resin represented by formula (I) include the following: Resin-[Z k -O-CH2CO-NH-(CH2)3-Si(OCH2CH3)3] q ; Resin-[Z k -O-CO-CH(CH2COOH)-(CH2)3-Si(OCH2CH3)3] q ; Resin-[Z k -CO-NH-(CH2)3-Si(OCH2CH3)3] q ; Resin-[Z k -CO-(CH2)2-CO-NH-(CH2)3-Si(OCH2CH3)3] q ; Resin-[Z k -O-CO-NH-(CH2)3-Si(OCH2CH3)3] q ; Resin-[Z k -O-(CH2)3-Si(OCH2CH3)3] q ; (In the formula, Z, k, and q are the same as defined above.) The number of silanes added, "q", may be any number, but may usually be 1 to 20, 1 to 19, 1 to 18, 1 to 17, 1 to 16, 1 to 15, 1 to 14, 1 to 13, 1 to 12, 1 to 11, 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2.

[0125] Other suitable examples of the silane-functionalized resins represented by formula (I) include the following: Resin-[Z k -X n -R 1 -(CH2) m -Si(R 2 ) p ] q ; Resin-Z k -SO2NH-(CH2)2-CH2-Si(OCH2CH3)3; Resin-Z k -SONH-(CH2)2-CH2-Si(OCH2CH3)3; Resin-Z k -S-(CH2)2-CH2-Si(OCH2CH3)3; Resin-Z k -SO-(CH2)2-CH2-Si(OCH2CH3)3; Resin-Z k -SO2-(CH2)2-CH2-Si(OCH2CH3)3; Resin-[Z k (COO(CH2)2OCOC(COCH3)N(CH2)3Si(OCH3)3)] q -resin; Resin-Z k -SO2NH-(CH2)2-CH2-Si(OCH2CH3)3; Resin-Z k -Ph-O-Si(OCH2CH3)3; (In the formula, Z, k, X, n, R 1 , m, R 2 , p, and q are the same as above.) The number of silanes added, "q", may be any number, but may usually be 1 to 20, 1 to 19, 1 to 18, 1 to 17, 1 to 16, 1 to 15, 1 to 14, 1 to 13, 1 to 12, 1 to 11, 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2.

[0126] The silane-functionalized resin represented by the formula (I) can be produced by a known method, for example, by the method described in JP-A-2020-513060.

[0127] In the rubber composition for treads, the content of the functionalized resin is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 18 parts by mass or more, and particularly preferably 20 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less. Within the above range, better effects tend to be obtained.

[0128] The rubber composition for treads may further contain other plasticizers in addition to the functionalized resin. Examples of other plasticizers include, but are not limited to, oils, liquid plasticizers having liquid plasticity at 25°C such as the liquid resins described above, and solid plasticizers having solid plasticity at 25°C such as the solid resins described above. These plasticizers may be used alone or in combination of two or more.

[0129] In the rubber composition for treads, the content of plasticizer (total amount of the functionalized resin, liquid plasticizers such as oils and liquid resins other than the functionalized resins, and solid plasticizers such as solid resins other than the functionalized resins) is preferably 7.5 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 18 parts by mass or more, and particularly preferably 20 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less. Within the above range, better effects tend to be obtained.

[0130] In the liquid plasticizer, the oil is not particularly limited, and conventionally known oils can be used, such as process oils such as paraffin-based process oils, aromatic process oils, naphthenic process oils, low PCA (polycyclic aromatic) process oils such as TDAE and MES, vegetable oils, and mixtures thereof. Among these, aromatic process oils are preferred. Specific examples of the aromatic process oils include the Diana Process Oil AH series manufactured by Idemitsu Kosan Co., Ltd.

[0131] In the liquid plasticizer, examples of the liquid resin include those described above. In the solid plasticizer, examples of the solid resin include those described above.

[0132] Examples of liquid plasticizers and solid plasticizers that can be used include products 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., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0133] The rubber composition for a tread preferably contains sulfur. The amount of sulfur is preferably 0.5 to 5.0 parts by mass, and more preferably 0.7 to 3.0 parts by mass, based on 100 parts by mass of the rubber component.

[0134] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc. Commercially available sulfur 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.

[0135] The rubber composition for tread preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is preferably 1.0 to 5.0 parts by mass, more preferably 1.5 to 4.5 parts by mass, per 100 parts by mass of the rubber component.

[0136] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolylguanidine, and orthotolylbiguanidine. These may be used alone or in combination of two or more. Of these, sulfenamide vulcanization accelerators and guanidine vulcanization accelerators are preferred.

[0137] The rubber composition for tread may contain wax, antioxidant, stearic acid, zinc oxide, and organic crosslinking agent.

[0138] In the tire 2 of FIG. 1, the tread 4 has a maximum thickness of 10.0 mm or less. Fig. 2 is an enlarged cross-sectional view showing the vicinity of the tread 4 of the tire 2 of Fig. 1. In Fig. 2, the up-down direction is the radial direction of the tire 2, the left-right direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2.

[0139] In FIG. 2, the symbol P denotes a point on the tread surface 24. Point P is located outside the axially innermost groove 26. The double-headed arrow T denotes the thickness of the tread 4 at point P. The thickness T is the sum of the thicknesses of the cap layer 30 and the base layer 28 at point P. This thickness T is measured along a normal to the tread surface 24 at point P. Note that while FIGS. 1 and 2 show an example of a two-layer tread 4 consisting of the cap layer 30 and the base layer 28, in the case of a single-layer tread 4, the tread thickness T is the thickness of the single-layer tread at point P. In the case of a tread having a three or more layer structure, the tread thickness T is the sum of the thicknesses of the three or more layers at point P, and in such a case, the thickness T at point P is also measured along a normal to the tread surface 24 at point P.

[0140] In FIG. 1, the maximum thickness of the tread 4 is the maximum dimension among the thicknesses of each tread at each point on the tread surface 24 (in FIG. 1, the total thickness of the cap layer 30 and the base layer 28), and this is 10.0 mm or less. The maximum thickness of the tread 4 is preferably 9.0 mm or less, more preferably 8.0 mm or less, and even more preferably 7.5 mm or less. The lower limit is preferably 5.5 mm or more, and more preferably 6.0 mm or more. Within the above range, better effects tend to be obtained.

[0141] In the tire 2 of FIG. 1, from the viewpoint of obtaining better effects, it is desirable that the above-mentioned acetone extractable content (mass %) and the maximum thickness (mm) of the tread 4 satisfy the following formula. Acetone extractables x maximum tread thickness < 83 The product of the amount of acetone extractables and the maximum tread thickness is preferably less than 80, more preferably 78 or less, even more preferably 77 or less, and particularly preferably 76 or less. The lower limit is preferably 50 or more, more preferably 60 or more, even more preferably 63 or more, and particularly preferably 65 or more. It is believed that the greater the tread thickness, the greater the centrifugal force acting on the tread portion, so by keeping the product by the amount of acetone extractables at a certain level or less, it becomes easier to prevent acetone extractables from detaching from the tread portion, and wet grip performance during high-speed driving tends to be further improved.

[0142] In the tire 2 of FIG. 1, from the viewpoint of obtaining better effects, it is desirable that the above-mentioned tan δ at 0° C. and the maximum thickness (mm) of the tread 4 satisfy the following formula. (tan δ at 0°C / maximum tread thickness) x 1000>60.0 (tan δ at 0°C / maximum tread thickness) x 1000 is preferably 70.0 or more, more preferably 75.0 or more, even more preferably 80.0 or more, and particularly preferably 87.5 or more. The upper limit is preferably 130.0 or less, more preferably 120.0 or less, even more preferably 110.0 or less, and particularly preferably 100.0 or less. It is thought that the thinner the tread thickness, the more suppressed the deformation of the tread portion and the less effective it is in improving wet grip performance during high-speed running. However, as the thickness becomes thinner, the low-temperature heat buildup increases, and therefore good wet grip performance during high-speed running tends to be more easily obtained.

[0143] In the tire 2 of FIG. 1, the tread 4 has an outer tire diameter D of 700 mm or less. The tire outer diameter D refers to the outer diameter of the tire when mounted on an applicable rim, inflated to a specified air pressure, and in an unloaded state. The tire outer diameter D is preferably 676 mm or less, more preferably 652 mm or less, even more preferably 635 mm or less, and particularly preferably 627 mm or less. There is no particular lower limit, but it is preferably 580 mm or more, more preferably 590 mm or more, even more preferably 600 mm or more, and particularly preferably 610 mm or more. Since it is believed that the larger the tire, the greater the centrifugal force acting on the tread portion. Therefore, by keeping the product of the amount of acetone extractables at a certain level or less, it becomes easier to prevent acetone extractables from detaching from the tread portion, and wet grip performance during high-speed driving tends to be further improved.

[0144] In the tire 2 of FIG. 1, from the viewpoint of obtaining better effects, it is desirable that the above-mentioned acetone extractable content (mass %) and the tire outer diameter D (mm) satisfy the following formula. Acetone extraction volume x tire outer diameter < 6500 The product of the amount of acetone extractables and the tire outer diameter is preferably 6,300 or less, more preferably 6,100 or less, even more preferably 6,000 or less, and particularly preferably 5,900 or less. The lower limit is preferably 4,000 or more, more preferably 4,500 or more, even more preferably 4,800 or more, and particularly preferably 5,000 or more. Within the above ranges, better effects tend to be obtained.

[0145] In the tire 2 of FIG. 1, from the viewpoint of obtaining better effects, it is desirable that the above-mentioned tan δ at 0° C. and the tire outer diameter D (mm) satisfy the following formula. (tan δ at 0°C / tire outer diameter) x 1000>0.70 (tan δ at 0°C / tire outer diameter) x 1000 is preferably 0.90 or more, more preferably 0.96 or more, even more preferably 1.12 or more, and particularly preferably 1.28 or more. The upper limit is preferably 2.00 or less, more preferably 1.80 or less, even more preferably 1.60 or less, and particularly preferably 1.40 or less. Within the above range, the effect tends to be more favorable.

[0146] In the tire 2 of Fig. 1, each sidewall 6 extends substantially radially inward from an end of the tread 4. A radially outer portion of each sidewall 6 is joined to the tread 4. A radially inner portion of each sidewall 6 is joined to a clinch 10.

[0147] Each wing 8 is located between the tread 4 and the sidewall 6. The wing 8 is joined to each of the tread 4 and the sidewall 6.

[0148] Each clinch 10 is located approximately radially inward of the sidewall 6. The clinches 10 are located axially outward of the beads 12 and the carcass 14.

[0149] Each bead 12 is located axially inward of the clinch 10. The bead 12 includes a core 32 and an apex 34 extending radially outward from the core 32. The core 32 is ring-shaped and includes a wound non-stretchable wire or the like. The apex 34 tapers radially outward.

[0150] The carcass 14 includes a carcass ply 36. In the tire 2, the carcass 14 is made up of one carcass ply 36, but may be made up of two or more carcass plies.

[0151] In the tire 2, the carcass ply 36 is laid between the beads 12 on both sides and extends along the tread 4 and the sidewall 6. The carcass ply 36 is folded back from the inside to the outside in the axial direction around each core 32. This folding back forms a main portion 36a and a pair of folded back portions 36b in the carcass ply 36. That is, the carcass ply 36 includes the main portion 36a and the pair of folded back portions 36b.

[0152] Although not shown, the carcass ply 36 may be made up of a number of parallel cords and a topping rubber, etc. The carcass 14 preferably has a radial structure.

[0153] The belt 16 is located radially inside the tread 4. The belt 16 is laminated with the carcass 14. The belt 16 is made up of an inner layer 38 and an outer layer 40.

[0154] Although not shown, each of the inner layer 38 and the outer layer 40 may be formed of a large number of parallel cords and a topping rubber. Each cord is, for example, inclined with respect to the equatorial plane. The inclination direction of the cords of the inner layer 38 with respect to the equatorial plane is opposite to the inclination direction of the cords of the outer layer 40 with respect to the equatorial plane.

[0155] The band 18 is located radially outside the belt 16. In the axial direction, the band 18 has a width equal to the width of the belt 16. The band 18 may also have a width greater than the width of the belt 16.

[0156] Although not shown, the band 18 may be made of a cord and a topping rubber, etc. The cord is wound spirally, for example.

[0157] The belt 16 and the band 18 form a reinforcing layer. The reinforcing layer may be formed of the belt 16 alone.

[0158] The inner liner 20 is located inside the carcass 14. The inner liner 20 is joined to the inner surface of the carcass 14.

[0159] Each chafer 22 is located near the bead 12. In this embodiment, the chafer 22 may be made of a cloth and rubber impregnated into the cloth. The chafer 22 may be integrated with the clinch 10.

[0160] In this tire 2, the tread 4 has main grooves 42 as the grooves 26. As shown in FIG. 1 , a plurality of main grooves 42, specifically three main grooves 42, are formed in the tread 4. These main grooves 42 are spaced apart in the axial direction. The three main grooves 42 formed in the tread 4 form four ribs 44 extending in the circumferential direction. In other words, the spaces between the ribs 44 constitute the main grooves 42.

[0161] Each of the main grooves 42 extends in the circumferential direction and is continuous without interruption in the circumferential direction.

[0162] In manufacturing this tire 2, multiple rubber components are assembled to obtain a raw cover (unvulcanized tire 2). This raw cover is placed in a mold. The outer surface of the raw cover abuts against the cavity surface of the mold. The inner surface of the raw cover abuts against a bladder or core. The raw cover is pressurized and heated in the mold. The pressure and heat cause the rubber composition of the raw cover to flow. The heat causes a crosslinking reaction in the rubber, and the tire 2 is obtained. The uneven pattern is formed in the tire 2 by using a mold with an uneven pattern on its cavity surface.

[0163] Examples of the tire 2 include pneumatic tires and non-pneumatic tires. Among these, pneumatic tires are preferred. For example, they can be suitably used as summer tires and winter tires (studless tires, snow tires, studded tires, etc.). The tires can be used as passenger car tires, tires for large passenger cars, tires for large SUVs, heavy-duty tires for trucks and buses, tires for light trucks, tires for motorcycles, racing tires (high-performance tires), etc. [Example]

[0164] The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0165] The various chemicals used in the examples and comparative examples will be collectively described below. NR:TSR20 SBR1: Production Example 1 below (styrene content 25% by mass, vinyl content 25% by mass) SBR2: Europrene SOL® C2525 (styrene content 25% by mass, vinyl content 25% by mass) manufactured by Versalis SBR3: HPR850 manufactured by JSR Corporation (styrene content 26% by mass, vinyl bond content 59% by mass) BR: BR150B (cis content 97% by mass) manufactured by Ube Industries, Ltd. Carbon black: N220 (N2SA114m) manufactured by Cabot Japan Co., Ltd. 2 / g) Silica: Ultrasil VN3 (N2SA175m) manufactured by Evonik Degussa 2 / g) Silane coupling agent 1: NXT (3-octanoylthiopropyltriethoxysilane) manufactured by Momentive Silane coupling agent 2: NXT-Z45 (a copolymer of bonding unit A and bonding unit B (bonding unit A: 55 mol %, bonding unit B: 45 mol %)) manufactured by Momentive Solid resin: SYLVARES SA85 (copolymer of α-methylstyrene and styrene, softening point 85°C) manufactured by Arizona Chemical Co. Functionalized resin: Preparation Example 2 below Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Antioxidant 6C: Nocrac 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent FR: Antigen FR manufactured by Sumitomo Chemical Co., Ltd. (a quinoline-based anti-aging agent, purified from the reaction product of amine and ketone, with no residual amine) Stearic acid: Tsubaki (NOF Corporation) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccelaer D (N,N'-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0166] (Production Example 1) Cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were charged into a nitrogen-purged autoclave reactor. After adjusting the temperature of the reactor contents to 20°C, n-butyllithium was added to initiate polymerization. Polymerization was carried out under adiabatic conditions, with the maximum temperature reaching 85°C. When the polymerization conversion reached 99%, 1,3-butadiene was added, and the polymerization was continued for an additional 5 minutes. N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane was then added as a modifier, and the reaction was continued. After the polymerization reaction was completed, 2,6-di-tert-butyl-p-cresol was added. The solvent was then removed by steam stripping, and the mixture was dried on a heated roll heated to 110°C to obtain SBR1.

[0167] (Preparation Example 2: Synthesis of end-capped silane-containing resin by phenol functionalization) A phenol-functionalized end-capped silane-containing resin was synthesized according to the steps shown in Figure 3 as follows.

[0168] Step A: Synthesis of end-capped COOH-functionalized resins by phenolic group functionalization: A three-necked, 2 L round-bottom flask equipped with a mechanical stirrer and reflux condenser was charged with 100.6 g of 10.8 mol% phenol-functionalized resin (902 mmol containing 97.2 mm of phenolic units) and 1.50 L of acetone. Once the resin was completely dissolved with stirring, 10.55 g of potassium iodide, 6.48 g of sodium hydroxide, and 101.1 g of sodium chloroacetate were added. The reaction solution was heated to 57 °C for 18 h. The solvent was removed, and the product was dissolved in 3 L of dichloromethane (DCM) and washed with 1.2 L of 1 M aqueous HCl. The biphasic solution was stirred until all solids were completely dissolved. The aqueous layer was discarded. The solution was washed with 1 M aqueous HCl, 1 M aqueous NaOH, and then 1 M aqueous HCl. This procedure was repeated, with four additional washes with 1 M aqueous HCl as needed. The organic phase was dried over anhydrous MgSO4. The MgSO4 was removed by gravity filtration on a paper filter. The solvent was removed and the product was dried under vacuum at room temperature overnight. The product weighed 103.8 g (98% of the theoretical yield).

[0169] Step B: Synthesis of end-capped silane-functionalized resin by COOH group functionalization: A three-necked, 3 L round-bottom flask equipped with a thermometer and stir bar was charged with 106.0 g of 10.8 mol% carboxylic acid-containing resin (900 mmol, containing 97.0 mmol of carboxylic units) and 2.70 L of DCM. The solution was placed under a N2 blanket and magnetically stirred. Once the resin was completely dissolved, the flask was cooled in an ice / NaCl / water bath. When the temperature reached 2.5 ± 2.5 °C, 10.75 g of ethyl chloroformate (99.1 mmol) was added, followed by 9.97 g of TEA (98.5 mmol). The activation time (mixed anhydride formation) was 32 minutes at 5 ± 3 °C. Next, 21.58 g of 3-aminopropyltriethoxysilane (97.5 mmol) was added. The cooling bath was removed, and the reaction was allowed to warm to room temperature. The reaction was continued at room temperature for 25 hours. The insoluble material (triethylamine hydrochloride) was removed by gravity filtration on a Whatman® #1 filter paper. Next, 300 mL of hexane was added. The mixture was stirred for 30 minutes and stored in the refrigerator for 48 hours. The two-phase system was allowed to warm to room temperature. The upper hexane layer was isolated and the solvent was removed. The product was dried under reduced pressure at room temperature for 2-3 days. Dry ethanol was used to facilitate the removal of the hexane. The waxy product weighed approximately 80 g (63-64% of the theoretical yield). An alternative workup step was to remove all solvent under reduced pressure after the reaction was complete and dissolve the product in diethyl ether or methyl tert-butyl ether (MTBE). The solution was then filtered on a filter paper to remove the triethylamine hydrochloride by-product, and the solvent was slowly evaporated. The product was dried under reduced pressure at room temperature to yield a phenol-functionalized end-capped silane-containing resin.

[0170] <Examples and Comparative Examples> According to the formulation shown in Table 1, materials other than sulfur and 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 mixture. Next, sulfur and vulcanization accelerator were added to the obtained kneaded mixture, 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 a tread shape and laminated together with other tire components to form an unvulcanized tire. This was press-vulcanized for 12 minutes at 150°C to produce a test tire with the specifications shown in Table 1. The details of the specifications of the test tires with the tire outer diameters shown in Table 1 are as follows: (1)245 / 45R16, external size: 627mm (2)245 / 45R17, external size: 652mm (3)245 / 55R16, external size: 676mm

[0171] Using the obtained test tires of each size, the following physical property measurements and evaluations were carried out according to the specifications in each table, and the results are shown in each table. Note that the reference comparative example in Table 1 was Comparative Example 1.

[0172] <Viscoelasticity test> A viscoelasticity measurement sample measuring 20 mm in length, 4 mm in width, and 1 mm in thickness was taken from inside the rubber layer of the tread of each test tire, with the long side aligned in the tire circumferential direction, and the loss tangent tanδ of each rubber layer was measured using an Iplexer series manufactured by GABO under the conditions of a temperature of 0°C, an initial strain of 5%, a dynamic strain of 1%, a frequency of 10 Hz, and an extension mode. The thickness direction of the sample was the tire radial direction.

[0173] <Amount of acetone extracted (AE amount)> For rubber test pieces cut out from the tread of the test tire, the amount of substance contained in the test piece that could be extracted with acetone was measured according to the method for measuring acetone extractables in accordance with JIS K 6229. Acetone extractable amount (mass%) = (mass of sample before extraction - mass of sample after extraction) / mass of sample before extraction × 100

[0174] <density> Regarding the density of a rubber test piece cut out from the tread of the test tire, the mass in ethanol and the mass in air were measured, and the density was calculated based on these.

[0175] <Wet grip performance at high speeds> The test tires were mounted on a 2000cc domestic FR vehicle, and the vehicle was driven 10 laps on a test course with a wet asphalt surface (high-speed driving: average speed of 100km / h).The braking distance from 100km / h was then measured and expressed as an index (wet grip performance index at high speeds), with the reference comparative example being set at 100.A higher index indicates better wet grip performance at high speeds.

[0176] [Table 1]

[0177] The tires of the examples, which contained a rubber component having a predetermined total content of isoprene-based rubber, BR, and SBR with a low styrene content and a low vinyl content, and silica, and which had a tread with a predetermined tan δ at 0°C, acetone extractables, and density, and which also had a predetermined maximum tread thickness and tire outer diameter, had excellent wet grip performance when running at high speeds. [Explanation of symbols]

[0178] 2. Pneumatic tires 4 Tread 6 Sidewall 8 Wing 10 Clinch 12 beads 14 Carcass 16 Belt 18 bands 20 Inner liner 22 Chafer 24 Tread surface 26 Groove 28 base layer 30 cap layers 32 cores 34 Apex 36 Carcass ply 36a Main part 36b Folded part 38 Inner layer 40 outer layer 42 Main groove 44 Ribs CL Equatorial plane of tire 2 P is a point on the tread surface 24 T Tread 4 Thickness D Tire outer diameter

Claims

1. A tire having a tread, The tread comprises a rubber component having a total content of 90% by mass or more of isoprene rubber, butadiene rubber, and styrene butadiene rubber having a styrene content of 30% by mass or less and a vinyl content (amount of 1,2-bonded butadiene units) of less than 30% by mass, and silica, and has a tan δ at 0°C of 0.50 or more, an acetone extractable content of 10.0% by mass or less, and a density of 1.30 g / cm ３ A layer made of the following rubber composition is provided: The tire has a maximum tread thickness of 10.0 mm or less and an outer diameter of 700 mm or less.

2. 10. The tire of claim 1, wherein the tread comprises a modified diene-based rubber and / or a functionalized resin having functional groups capable of reacting with silica.

3. 3. The tire according to claim 1, wherein the tread contains 80 parts by mass or less of the silica per 100 parts by mass of the rubber component.

4. The tire according to any one of claims 1 to 3, wherein the tread contains a mercapto-based silane coupling agent.

5. The tire according to any one of claims 1 to 4, wherein the contents of the isoprene-based rubber, the butadiene rubber, and the styrene-butadiene rubber in 100% by mass of the rubber component satisfy the following formula: [Isoprene rubber content / (butadiene rubber content+styrene butadiene rubber content)]≦0.50

6. The tire according to any one of claims 1 to 5, wherein the tread contains the isoprene-based rubber, the butadiene rubber, and the styrene-butadiene rubber.

7. 3. The tire of claim 2, wherein the functionalized resin comprises a functionalized resin having a functional group comprising at least one element selected from the group consisting of oxygen, silicon, and nitrogen.

8. The tire according to any one of claims 1 to 7, wherein the amount of acetone extractables and the maximum thickness of the tread satisfy the following formulas: Acetone extractables x maximum tread thickness < 80

9. The tire according to any one of claims 1 to 8, wherein the acetone extractable amount and the tire outer diameter satisfy the following formula: Acetone extractable amount x tire outer diameter < 6500

10. 10. The method according to claim 1, wherein the tan δ at 0° C. and the maximum thickness of the tread satisfy the following formula: Any tire as described above. (tan δ at 0°C / maximum tread thickness) × 1000 > 60.0

11. The tire according to any one of claims 1 to 10, wherein the tan δ at 0°C and the tire outer diameter satisfy the following formula: (tan δ at 0°C / tire outer diameter)×1000>0.70

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