tire

Abstract

To provide a tire that can improve wet grip performance and handling stability at high speeds. [Solution] A tire having a tread, wherein the tread has one or more circumferential grooves, the tread is composed of a rubber composition containing a rubber component, a filler, and a resin component, the rubber component contains 40% by mass or more of isoprene rubber and more than 40% by mass of styrene-butadiene rubber, the filler contains silica, the rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of the resin component per 100 parts by mass of the rubber component, and when the land ratio of the tread is R and the total content of the filler in the rubber composition per 100 parts by mass of the rubber component is F (parts by mass), the tire has a land ratio of R and F greater than 65.

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] Patent Document 1 describes that a tire provided with a tread composed of a rubber composition containing isoprene rubber and silica and having 20°C tanδ and -20°C tanδ within a predetermined range has well-balanced improvements in low fuel consumption performance, wear resistance performance, handling stability during high-speed driving, and wet grip performance during high-speed driving.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When isoprene rubber and styrene-butadiene rubber are used in combination to improve grip performance, silica tends to be unevenly distributed in the styrene-butadiene rubber phase, and it is difficult to ensure the dispersibility of silica. Therefore, there is room for improvement in enhancing the various performances of the tire.

[0005] An object of the present invention is to provide a tire capable of improving the overall performance of wet grip performance and handling stability performance during high-speed driving.

Means for Solving the Problems

[0006] The present invention relates to a tire having a tread, wherein the tread has one or more circumferential grooves, the tread is composed of a rubber composition containing a rubber component, a filler, and a resin component, the rubber component contains 40% by mass or more of isoprene rubber and more than 40% by mass of styrene-butadiene rubber, the filler contains silica, the rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of the resin component per 100 parts by mass of the rubber component, and when the land ratio of the tread is R and the total content of the filler in the rubber composition per 100 parts by mass of the rubber component is F (parts by mass), the tire has a land ratio of R × F greater than 65. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the overall performance of wet grip performance and handling stability performance at high speeds. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the contact surface of a tire when the tread is pressed against a flat surface. [Modes for carrying out the invention]

[0009] A tire according to one embodiment of the present invention is a tire having a tread, wherein the tread has one or more circumferential grooves, the tread is composed of a rubber composition containing a rubber component, a filler, and a resin component, the rubber component contains 40% by mass or more of isoprene rubber and more than 40% by mass of styrene-butadiene rubber, the filler contains silica, the rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of the resin component per 100 parts by mass of the rubber component, and when the land ratio of the tread is R and the total content of the filler in the rubber composition per 100 parts by mass of the rubber component is F (parts by mass), the tire has a ratio of R × F greater than 65.

[0010] The reason why the overall performance of wet grip performance and handling stability performance at high speeds is improved in the tire of the present invention is thought to be as follows, although we do not intend to be bound by theory.

[0011] The rubber composition constituting the tire tread of the present invention has the following advantages: (1) By including 40% by mass or more isoprene-based rubber, which has weak interaction with silica, the polymer phase in the rubber composition can move flexibly, improving the mobility of the polymer. As a result, the ability to follow the road surface at a microscopic level is improved, contributing to improved wet grip performance. Furthermore, (2) by including more than 40% by mass of styrene-butadiene rubber, the heat generation of the tread rubber is improved, which is thought to improve wet grip performance. Furthermore, (3) by including 100 parts by mass or more of silica, the reinforcing properties of the tread rubber are improved, which is thought to improve handling stability during high-speed driving. Furthermore, (4) by including 20 parts by mass or more of resin components, the heat generation of the tread rubber is improved, which is thought to improve wet grip performance.

[0012] Furthermore, it is believed that the tire of the present invention can improve handling stability at high speeds by (5) setting R×F to more than 65 and securing the amount of filler per unit contact area to improve the reinforcing properties of the tread rubber.

[0013] Furthermore, it is believed that the combined efforts of (1) to (5) above will achieve a remarkable effect: an improvement in overall performance, specifically in low-wet grip performance and handling stability at high speeds.

[0014] From the viewpoint of the effects of the present invention and wear resistance, the rubber composition preferably contains 130 parts by mass or more of silica per 100 parts by mass of the rubber component.

[0015] The CTAB specific surface area C of the silica is 190 m², from the viewpoint of the effects of the present invention and wear resistance performance. 2 It is preferable that the amount is 1 / g or more.

[0016] From the viewpoint of further improving wet grip performance, the rubber composition preferably contains 50 parts by mass or more of the resin component per 100 parts by mass of the rubber component.

[0017] From the viewpoint of the effects of the present invention and low fuel consumption performance, the styrene content of the styrene-butadiene rubber is preferably 20% by mass or less.

[0018] The amount of acetone extracted from the rubber composition (AE) (mass%) is preferably 25.0 or more.

[0019] From the viewpoint of the effects of the present invention, the aforementioned resin component preferably contains at least one selected from the group consisting of C9 resins, dicyclopentadiene resins, and terpene resins.

[0020] From the viewpoint of particularly improving wet grip performance, it is preferable that the rubber composition further contains a mercapto-silane coupling agent.

[0021] The aforementioned resin component preferably contains a liquid resin, particularly from the viewpoint of improving wet grip performance.

[0022] The aforementioned rubber composition preferably contains liquid rubber, particularly from the viewpoint of improving wet grip performance.

[0023] The aforementioned rubber composition is preferably further enriched with vegetable oil, particularly from the viewpoint of improving wet grip performance.

[0024] When the amount of acetone extracted from the rubber composition is defined as AE (mass%), it is preferable that F × AE is greater than 3500. By setting F × AE within the above range, the flexibility and contact area of ​​the tread rubber can be ensured, and it is believed that the wet grip performance, in particular, can be improved.

[0025] When the amount of acetone extracted from the rubber composition is defined as AE (mass%), it is preferable that R×AE is greater than 15. By setting R×AE within the above range, it is believed that the decrease in wet grip performance due to a smaller contact area of ​​the tread can be suppressed.

[0026] The maximum load capacity of the aforementioned tire is W L (kg), if the weight of the tire is G (kg), then G / W L From the viewpoint of the effects of the present invention and low fuel consumption performance, it is preferable that the value is 0.0170 or less.

[0027] <Definition> "Standard condition" refers to a state of no load where the tire is mounted on a standard rim and filled with air at the standard internal pressure. Unless otherwise specified, tires in the standard condition should be used.

[0028] Unless otherwise specified, the "dimensions of each part of the tire" refer to values ​​that are determined in the normal state for those visible on the outer surface of the tire, while those located inside the tire or on the cut surface of the tire refer to values ​​that are determined, for example, by cutting the tire in a plane including the tire's axis of rotation and holding the cut tire piece within the rim width of the normal rim.

[0029] A "standard rim" refers to the rim specified for each tire within the standards system that the tire is based on. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," for ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." Refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. In the case of a tire not specified in the above standards, it refers to the narrowest rim width among the smallest diameter rims that can be mounted on that tire and that can maintain internal pressure (i.e., do not cause air leakage between the rim and tire).

[0030] "Regular internal pressure" refers to the air pressure specified for each tire in the standards system, including the standard on which the tire is based. For example, for JATMA it refers to "maximum air pressure," for ETRTO it refers to "INFLATION PRESSURE," and for TRA it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims, refer to JATMA, ETRTO, and TRA in that order, and if there is an applicable size at the time of reference, follow that standard. In the case of tires not specified in the above standards, it refers to the regular internal pressure (but at least 250kPa) of another tire size (but specified in the standard) that is listed with the aforementioned regular rim as the standard rim. If multiple regular internal pressures of 250kPa or higher are listed, refer to the lowest value among them.

[0031] "Regular load (kg)" refers to the load specified for each tire in the standard system that the tire is based on. For example, for JATMA it is "Maximum Load Capacity," for ETRTO it is "LOAD CAPACITY," and for TRA it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims and regular in-tire pressure, refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. For tires not specified in the above standards, the maximum load capacity (kg) is calculated separately. L This is considered the normal load.

[0032] "Maximum load capacity W L The weight (kg) is calculated using the following formula: "V" is the virtual volume of the tire (mm²). 3 ), "Dt" is the outer diameter of the tire in the normal state (mm), "Ht" is the height of the tire's cross-section in the radial direction in a plane containing the tire's axis of rotation (mm), and "Wt" is the width of the tire's cross-section in the normal state (mm). Ht can be calculated by (Dt-R) / 2, where R is the rim diameter of the tire. Wt is the value obtained by removing any patterns or letters on the tire's sidewall. Note that the maximum load capacity is synonymous with the normal load mentioned above.

[0033]

number

[0034] "Tire weight G (kg)" refers to the weight of the tire alone, excluding the weight of the rim. However, if the tire contains components such as sponge or sealant, or sensor components within its internal cavity, the weight includes these components.

[0035] The "tread" is a component that includes the part that forms the contact surface of the tire. In a cross-section of the tire with a plane including the tire's axis of rotation, if the tire has components that form the tire's skeleton using steel or textile materials, such as belt layers, belt reinforcement layers, and carcass layers, the "tread" is a component that is positioned radially outward from these components.

[0036] The "contact area" refers to the area where the tread surface makes contact with the ground when a tire is mounted on a standard rim, subjected to standard internal pressure, and loaded with a standard load.

[0037] The "land ratio R" is the ratio (%) of the area of ​​the contact patch excluding the area of ​​grooves and sipes to the total area of ​​the contact patch with all grooves and sipes filled in. The total area of ​​the contact patch and the areas of grooves and sipes used to calculate the land ratio are determined by mounting the tire on a standard rim, applying standard internal pressure, marking the tire tread surface with ink, applying standard load, pressing it onto cardboard (camber angle 0°), and transferring the image. The transfer is performed at five locations, rotating the tire 72° in the circumferential direction each time. The land ratio is the average of these five locations.

[0038] A "groove" refers to a recessed area formed in the tire tread where the opening width at the tread contact surface is 2.0 mm or more. A recessed area where the opening width at the tread contact surface is less than 2.0 mm is called a "sipe."

[0039] "Circumferential grooves" refer to grooves that extend in the circumferential direction of the tire. Circumferential grooves may extend in a straight line along the circumferential direction, or they may extend in a wavy, sinusoidal, or zigzag pattern along the circumferential direction.

[0040] "Rubber components of a rubber composition" refer to components that contribute to crosslinking within a rubber composition, and generally have a weight-average molecular weight (Mw) of 10,000 or more.

[0041] A "plasticizer" is a material that imparts plasticity to rubber components and is extracted from rubber compositions using acetone. Plasticizers include those that are liquid at 25°C and those that are solid at 25°C. However, waxes and stearic acid commonly used in the tire industry are excluded.

[0042] "Plasticizer content" includes the amount of plasticizer contained in the extensible rubber component that has been pre-stretched with plasticizers such as oil, resin components, and liquid rubber. The same applies to the oil content, resin component content, and liquid rubber content; for example, if the extensible component is oil, the extensible oil is included in the oil content.

[0043] "Styrene content" can be determined by pyrolysis gas chromatography or NMR measurement. 1 H-NMR and 13 It is calculated by 13C-NMR. Unlike physical properties such as the complex modulus (E*), the amount of components such as "styrene content" has a true value that does not depend on the measurement method, so it is preferable to use a measurement method that is as accurate as possible. In this specification, "pyrolysis gas chromatography" refers to a method in which a sample is heated by a pyrolysis apparatus, the individual components contained in the gas phase components produced by this heating are separated by a separation column, and each isolated component is analyzed. Styrene content is applied to rubber components that have repeating units (styrene units) derived from styrene, such as SBR.

[0044] The "styrene content (mass%) of styrene-butadiene rubber" is the styrene content (mass%) of styrene-butadiene rubber (SBR). If only one type of SBR is contained in the rubber component, it is the styrene content of that SBR. If multiple types of SBR are contained in the rubber component, it is calculated by summing the products of the styrene content of each SBR and the amount of that SBR blended (mass%) when the total SBR is set to 100% by mass.

[0045] For example, when the rubber component consists of 20% by mass of a first SBR (styrene content: 25% by mass), 30% by mass of a second SBR (styrene content: 27.5% by mass), and 50% by mass of BR, the styrene content of the styrene-butadiene rubber is 26.5% by mass (= (25 × 40 / 100) + (27.5 × 60 / 100)).

[0046] The "vinyl content (amount of 1,2-bonded butadiene units)" is calculated by pyrolysis gas chromatography or NMR measurement ( 1 1H-NMR or 13 13C-NMR). Similar to the "styrene content", since there is a true value that does not depend on the measurement method for the "vinyl content", it is preferable to use a measurement method with as high precision as possible. The vinyl content is applied to, for example, rubber components having repeating units derived from butadiene such as SBR and BR.

[0047] The "cis content (amount of cis-1,4-bonded butadiene units)" is a value measured by infrared absorption spectroscopy or NMR measurement ( 1 1H-NMR or 13 13C-NMR) in accordance with JIS K 6239-2:2017, and is applied to, for example, rubber components having repeating units derived from butadiene such as BR. Similar to the "styrene content", since there is a true value that does not depend on the measurement method for the "cis content", it is preferable to use a measurement method with as high precision as possible.

[0048] The "acetone extraction amount AE" is a value obtained by immersing each rubber test piece in acetone for 72 hours in accordance with JIS K 6229:2015 to extract soluble components, measuring the mass of each rubber test piece before and after extraction, and using the following formula. Acetone extraction amount AE (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0049] The "glass transition temperature (Tg) of the rubber component" is the static glass transition temperature of each rubber component obtained by a differential scanning calorimeter (for example, Q200 manufactured by TA Instruments Japan Co., Ltd.).

[0050] The "weight-average molecular weight (Mw)" can be determined by converting the measured value using gel permeation chromatography (GPC) (for example, the GPC-8000 series manufactured by Tosoh Corporation, with a differential refractometer as the detector and TSKgel® SuperMultiporeHZ-M column manufactured by Tosoh Corporation) to a standard polystyrene equivalent. This method is applicable, for example, to SBR, BR, plasticizers, etc.

[0051] The nitrogen adsorption specific surface area (N2SA) of carbon black is measured in accordance with JIS K 6217-2:2017.

[0052] The nitrogen adsorption specific surface area (N2SA) of silica is measured by the BET method in accordance with ASTM D3037-93.

[0053] The "CTAB (cetyltrimethylammonium bromide) specific surface area C of silica" is measured in accordance with ASTM D3765-92. If only one type of silica is contained in the rubber composition, the "CTAB specific surface area C of silica" is the CTAB specific surface area of ​​that silica. If multiple types of silica are contained in the rubber composition, it is determined by the sum of the products of the CTAB specific surface area of ​​each silica and the amount of silica (mass%) it is included in the composition, assuming the total silica is 100% by mass.

[0054] The "average primary particle diameter" is a value obtained by photographing particles with a transmission or scanning electron microscope and taking the arithmetic mean of the particle diameters of 400 particles. If the particle shape is spherical, the diameter of the sphere is used as the particle diameter; if it is not spherical, the equivalent diameter of a circle (the positive square root of {4 × (particle area) / π}) is calculated from the microscope image and used as the particle diameter. The average primary particle diameter is applied to silica, carbon black, and other materials.

[0055] The "softening point of the resin component" is the temperature at which the sphere descends when the softening point specified in JIS K 6220-1:2015 7.7 is measured using a ring-type softening point measuring device.

[0056] [tire] One embodiment of the present invention is a tire having a tread, wherein the tread has one or more circumferential grooves, and the tread is composed of a rubber composition containing a rubber component, a filler, and a resin component, wherein the rubber component contains 40% by mass or more of isoprene rubber and more than 40% by mass of styrene-butadiene rubber, the filler contains silica, the rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of the resin component per 100 parts by mass of the rubber component, and when the land ratio of the tread is R and the total content of the filler in the rubber composition per 100 parts by mass of the rubber component is F (parts by mass), the tire has a land ratio of R × F greater than 65. The tire according to this embodiment will be described below with reference to the drawings. Note that the embodiments shown below are merely examples, and the tire of the present invention is not limited to the embodiments shown below.

[0057] Figure 1 is a schematic diagram of the contact surface when the tread is pressed against a flat surface. A tread pattern is formed on the tread surface 1 that constitutes the tire according to this embodiment.

[0058] In Figure 1, the tread has multiple circumferential grooves 4. The circumferential grooves 4 extend linearly along the circumferential direction C, but are not limited to this configuration. For example, they may extend in a wavy, sinusoidal, or zigzag pattern along the circumferential direction. In Figure 1, three circumferential grooves 4 are provided, but in this embodiment, the number of circumferential grooves is not particularly limited and may be, for example, two to five.

[0059] The shoulder land area 3 is a pair of land areas formed between the circumferential groove 4 and the tread edge Te. The center land area 2 is a land area formed between the pair of shoulder land areas 3. In Figure 1, two center land areas 2 are provided, but the number of center land areas is not particularly limited and may be, for example, one to five.

[0060] Preferably, at least one of the land portions has a widthwise groove that does not communicate with the circumferential groove 4 at one or both ends, and that both ends of the widthwise groove does not communicate with the circumferential groove 4. In Figure 1, the shoulder land portion 3 is provided with a widthwise groove 8 that communicates with the circumferential groove 4 at one end, and widthwise grooves 5 and 6 that do not communicate with the circumferential groove at both ends. The center land portion 2 is provided with a widthwise groove 7 that communicates with the circumferential groove 4 at one end, and a groove 9 that extends in the tire width direction, crosses the center land portion 2, and communicates with the circumferential groove at both ends, but the configuration is not limited to this.

[0061] The tread according to this embodiment may be a tread consisting of a single rubber layer, or it may be a tread having an outer layer that constitutes the tread surface (cap rubber layer) and one or more rubber layers (inner rubber layers) that exist between the cap rubber layer and the belt layer.

[0062] In this specification, "rubber composition constituting the tread" refers to the rubber composition constituting the cap rubber layer when the tread consists of two or more layers.

[0063] The maximum load capacity of the tire according to this embodiment W L From the viewpoint of better demonstrating the effects of the present invention, the (kg) is preferably 300 or more, more preferably 400 or more, even more preferably 450 or more, even more preferably 500 or more, even more preferably 550 or more, and particularly preferably 600 or more. Also, the maximum load capacity W L The (kg) can be, for example, 1300 or less, 1200 or less, 1100 or less, 1000 or less, 900 or less, 800 or less, or 700 or less, from the viewpoint of better demonstrating the effects of the present invention. L This can be increased by increasing the virtual volume V of the space occupied by the tire, and conversely, it can be decreased by increasing it.

[0064] The weight G (kg) of the tire according to this embodiment is preferably 6.0 or more, more preferably 6.5 or more, even more preferably 7.0 or more, and particularly preferably 7.5 or more. On the other hand, there is no particular upper limit to the tire weight G (kg), but it is usually 100 or less, and can be, for example, 80 or less, 60 or less, 40 or less, 20 or less, 15 or less, etc. The tire weight G can be varied by conventional methods, that is, it can be increased by increasing the specific gravity of the tire or by increasing the thickness of each component of the tire, and vice versa.

[0065] Maximum load capacity W L Ratio of tire weight G (kg) to (kg) (G / W L From the viewpoint of the effects of the present invention, the G / W is preferably 0.0170 or less, more preferably 0.0160 or less, even more preferably 0.0150 or less, even more preferably 0.0145 or less, even more preferably 0.0140 or less, even more preferably 0.0135 or less, and particularly preferably 0.0130 or less. On the other hand, the G / W L The lower limit is not particularly limited from the viewpoint of the effects of the present invention, but for example, it can be 0.0110 or higher, 0.0115 or higher, 0.0120, or 0.0125 or higher.

[0066] From the viewpoint of the effects of the present invention, the land ratio R of the tire according to this embodiment is preferably 0.90 or less, more preferably 0.85 or less, even more preferably 0.80 or less, even more preferably 0.75 or less, and particularly preferably 0.70 or less. Furthermore, from the viewpoint of wear resistance performance, the land ratio R is preferably 0.50 or more, more preferably 0.54 or more, and even more preferably 0.58 or more.

[0067] <Acetone extraction amount AE> From the viewpoint of improving silica dispersibility, the acetone extract amount AE (mass%) of the rubber composition constituting the tread is preferably 16.0 or higher, more preferably 18.0 or higher, even more preferably 20.0 or higher, even more preferably 22.0 or higher, even more preferably 24.0 or higher, and particularly preferably 25.0 or higher. Furthermore, the acetone extract amount AE (mass%) is preferably 35.0 or lower, more preferably 33.0 or lower, and even more preferably 31.0 or lower.

[0068] <R×F> In the rubber composition constituting the tread, when the total content of filler per 100 parts by mass of rubber component in the rubber composition is F (parts by mass), R × F is greater than 65, preferably greater than 70, more preferably greater than 75, and even more preferably greater than 80, from the viewpoint of the effects of the present invention. On the other hand, there is no particular upper limit to R × F, but from the viewpoint of wear resistance performance, it is preferably less than 130, more preferably less than 125, and even more preferably less than 120. The total content of filler per 100 parts by mass of rubber component in the rubber composition, F (parts by mass), will be described later.

[0069] <F×AE> From the viewpoint of the effects of the present invention, F×AE is preferably greater than 2000, more preferably greater than 2500, even more preferably greater than 3000, and particularly preferably greater than 3500. On the other hand, there is no particular upper limit to F×AE, but from the viewpoint of wear resistance, it is preferably less than 6000, more preferably less than 5500, and even more preferably less than 5000.

[0070] <R×AE> From the viewpoint of the effects of the present invention, R×AE is preferably greater than 10, more preferably greater than 11, even more preferably greater than 12, even more preferably greater than 13, even more preferably greater than 14, even more preferably greater than 15, and particularly preferably greater than 16. On the other hand, there is no particular upper limit to R×AE, but from the viewpoint of wear resistance performance, it is preferably less than 22, more preferably less than 20, and even more preferably less than 18.

[0071] <R×C> In a rubber composition constituting a tread, the CTAB specific surface area of ​​silica contained in the rubber composition is C(m²). 2 When R×C is expressed as ( / g), from the viewpoint of the effects of the present invention, R×C is preferably greater than 100, more preferably greater than 110, more preferably greater than 120, even more preferably greater than 130, even more preferably greater than 140, and particularly preferably greater than 150. On the other hand, there is no particular upper limit to R×C, but from the viewpoint of wear resistance performance, it is preferably less than 200, more preferably less than 190, and even more preferably less than 180. The CTAB specific surface area of ​​silica is C(m²). 2 The details of / g) will be explained later.

[0072] [Rubber composition] The rubber composition constituting the tire tread according to this embodiment (hereinafter referred to as the rubber composition according to this embodiment) contains 100 parts by mass of silica and 20 parts by mass of resin components per 100 parts by mass of rubber components containing 40% by mass or more of isoprene rubber and more than 40% by mass of styrene-butadiene rubber, and the filler contains silica, all of which can be manufactured using the raw materials described below. The rubber composition according to this embodiment will be described below.

[0073] <Rubber components> In the rubber composition according to this embodiment, diene rubber is preferably used as the rubber component. Examples of diene rubber include isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). These diene rubbers may be modified rubbers treated with modifying groups that can interact with fillers such as carbon black or silica, or they may be hydrogenated rubbers in which some of the unsaturated bonds have been hydrogenated. One type of diene rubber may be used alone, or two or more types may be used in combination. In addition, as the diene rubber, stretched rubber that has been pre-stretched using a plasticizer described later may be used.

[0074] The content of diene rubber in the rubber component is preferably more than 80% by mass, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Alternatively, the rubber component may consist solely of diene rubber.

[0075] The rubber component according to this embodiment includes isoprene rubber and styrene-butadiene rubber, and preferably contains isoprene rubber, styrene-butadiene rubber, and butadiene rubber. Furthermore, the rubber component according to this embodiment may consist only of isoprene rubber and styrene-butadiene rubber, or it may consist only of isoprene rubber, styrene-butadiene rubber, and butadiene rubber.

[0076] (Isoprene rubber) As isoprene-based rubbers, for example, isoprene rubber (IR) and natural rubber, which are common in the tire industry, can be used. Natural rubber includes not only unmodified natural rubber (NR), but also modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, and grafted natural rubber. These isoprene-based rubbers may be used individually or in combination of two or more types.

[0077] NR is not particularly limited and can be any that is common in the tire industry, such as SIR20, RSS#3, TSR20, etc.

[0078] From the viewpoint of the effects of the present invention, the isoprene-based rubber content in the rubber component is 40% by mass or more, preferably more than 40% by mass, more preferably 42% by mass or more, even more preferably 45% by mass or more, even more preferably 48% by mass or more, and particularly preferably 50% by mass or more. Furthermore, the isoprene-based rubber content in the rubber component is preferably less than 60% by mass, more preferably 58% by mass or less, and even more preferably 55% by mass or less.

[0079] (SBR) There are no particular limitations on SBR, and examples include solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs thereof (modified S-SBR, modified E-SBR). Modified SBRs include SBRs in which the terminals and / or main chain are modified with a compound having the following functional groups (modifying agent); modified SBRs coupled with tin, silicon compounds, etc. (condensates, those with branched structures, etc.). Furthermore, hydrogenated products of these SBRs (hydrogenated SBRs) can also be used. These SBRs may be used individually or in combination of two or more types.

[0080] For the SBR, either oil-expanded SBR or non-oil-expanded SBR can be used. SBRs that can be used in this embodiment are commercially available from companies such as JSR Corporation, Sumitomo Chemical Co., Ltd., UBE Corporation, Asahi Kasei Corporation, ZS Elastomer Corporation, and ARLANXEO.

[0081] From the viewpoint of the effects of the present invention, the styrene content of SBR is preferably 30% by mass or less, more preferably 28% by mass or less, even more preferably 24% by mass or less, and particularly preferably 20% by mass or less. Furthermore, from the viewpoint of wet grip performance, the styrene content of SBR is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more. The styrene content of SBR is measured by the measurement method described above.

[0082] The vinyl content of SBR is preferably 5 mol% or more, more preferably 8 mol% or more, and even more preferably 10 mol% or more, from the viewpoint of ensuring reactivity with silica and abrasion resistance. Furthermore, the vinyl content of SBR is preferably 45 mol% or less, more preferably 40 mol% or less, even more preferably 35 mol% or less, even more preferably 30 mol% or less, and particularly preferably 25 mol% or less, from the viewpoint of elongation at break and abrasion resistance. The vinyl content of SBR is measured by the measurement method described above.

[0083] From the viewpoint of the effects of the present invention, the glass transition temperature (Tg) of SBR is preferably -40°C or lower, more preferably -50°C or lower, even more preferably -55°C or lower, and particularly preferably -60°C or lower. Furthermore, from the viewpoint of wear resistance, it is preferably -90°C or higher, more preferably -80°C or higher, and even more preferably -75°C or higher. The Tg of SBR is measured by the measurement method described above.

[0084] From the viewpoint of the effects of the present invention, the SBR content in the rubber component is more than 40% by mass, preferably 42% by mass or more, more preferably 44% by mass or more, and even more preferably 45% by mass or more. Furthermore, the SBR content in the rubber component is preferably 60% by mass or less, more preferably 58% by mass or less, even more preferably 55% by mass or less, even more preferably 53% by mass or less, and particularly preferably 50% by mass or less.

[0085] (BR) BR is not particularly limited, and for example, BR with a cis content of less than 50 mol% (low-cis BR), BR with a cis content of 90 mol% or more (high-cis BR), rare-earth butadiene rubber synthesized using a rare-earth element catalyst (rare-earth BR), BR containing syndiotactic polybutadiene crystals (SPB-containing BR), modified BR (high-cis modified BR, low-cis modified BR), etc., which are common in the tire industry, can be used. These BRs may be used individually or in combination of two or more types.

[0086] High-cis BR can be commercially available from companies such as Nippon Zeon Co., Ltd., UBE Corporation, and JSR Corporation. Including high-cis BR can improve low-temperature properties and wear resistance. The cis content of high-cis BR is preferably more than 95 mol%, more preferably more than 96 mol%, and even more preferably more than 97 mol%. The cis content of BR is measured by the measurement method described above.

[0087] From the viewpoint of wear resistance, the weight-average molecular weight (Mw) of BR is preferably over 300,000, more preferably over 350,000, and even more preferably over 400,000. From the viewpoint of crosslinking uniformity, it is preferably less than 2,000,000, more preferably less than 1,000,000, and even more preferably less than 500,000. Mw can be determined by the method described above.

[0088] The BR content in the rubber component is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, and particularly preferably 10% by mass or more. Furthermore, the BR content in the rubber component is preferably less than 20% by mass, more preferably 18% by mass or less, and even more preferably 16% by mass or less.

[0089] (Other rubber components) The rubber component may contain rubber components other than diene rubber (non-diene rubber) to the extent that it does not affect the effects of the present invention. As non-diene rubber, rubber components commonly used in the tire industry can be used, such as butyl rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, polyethylene chloride rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, etc. Other rubber components may be used alone or in combination of two or more. In addition to the above rubber components, known thermoplastic elastomers may or may not be included.

[0090] (Rubber components synthesized from recycled and biomass-derived raw materials) Monomers, which are the constituent units of synthetic rubbers such as IR, SBR, and BR, may be derived from underground resources such as petroleum and natural gas, or they may be recycled from rubber products such as tires or non-rubber products such as polystyrene. The monomers obtained by recycling (recycled monomers) are not particularly limited, but include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds are not particularly limited, but include styrene. In particular, it is preferable to use recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0091] The method for producing recycled monomer is not particularly limited, and for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Furthermore, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and pressure, decomposed by microwaves, or extracted after mechanical grinding.

[0092] Furthermore, the monomers that make up polymers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. Biomass is not particularly limited, but examples include agricultural, forestry, and fishery products, sugars, wood chips, plant residues after obtaining useful components, plant-derived ethanol, and biomass naphtha.

[0093] The biomass-derived monomer (biomass monomer) is not particularly limited and includes biomass-derived butadiene and biomass-derived aromatic vinyl compounds. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. Examples of the aromatic vinyl compound are not particularly limited but include styrene. Furthermore, the method for producing the biomass monomer is not particularly limited and includes, for example, biological and / or chemical and / or physical transformations of plants and animals. Typical biological transformations include fermentation by microorganisms, while chemical and / or physical transformations include those by catalysts, high heat, high pressure, electromagnetic waves, critical liquids, and combinations thereof.

[0094] The polymer synthesized from biomass monomer components (biomass polymer) is not particularly limited, and examples include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compounds. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0095] Whether the raw materials for a polymer are biomass-derived can be determined by measuring pMC (percent Modern Carbon) according to ASTM D6866-10. pMC refers to the percentage of modern standard reference carbon. 14 Sample relative to C concentration 14 This is a ratio of C concentrations and is used as an indicator of the biomass ratio of a compound. The significance of this value is described below.

[0096] 1 mole of carbon atoms (6.02 × 10⁻¹⁰) 23 (Each) contains approximately 6.02 × 10¹⁶ atoms, which is about one trillionth of the amount of carbon atoms in a normal atom. 11 individual 14 C exists. 14The half-life of C is 5730 years. 14 C is decreasing regularly. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been fixed after more than 226,000 years have passed since atmospheric carbon dioxide was taken in and fixed by plants, etc., C was initially included in these as well. 14 All elements of C have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas are no longer viable. 14 It contains absolutely no element C. Therefore, chemical substances produced using these fossil fuels as raw materials also contain C. 14 It contains absolutely no element C.

[0097] on the other hand, 14 C is continuously produced when cosmic rays undergo nuclear reactions in the atmosphere. Therefore, 14 In the Earth's atmospheric environment, carbon (C) is produced in a state where its decrease due to radioactive decay and its production through nuclear reactions are in equilibrium. 14 The amount of C is constant. Therefore, the amount of biomass resource-derived substances currently circulating in the environment 14 As mentioned above, the carbon concentration is approximately 1 × 10¹⁶ of the total carbon atoms. -12 These values ​​are approximately in mole percent. Therefore, the difference between these values ​​can be used to calculate the biomass ratio in a given compound.

[0098] this 14 C is typically measured as follows: Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 Perform measurement C). In the measurement, 14 As a modern standard reference for the concentration of C, the amount of cyclic carbon in nature as of 1950 14The C concentration will be used. The specific standard material will be the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific radioactivity of carbon in this oxalic acid (per gram of carbon) will be used. 14 The radioactivity intensity of C is separated by carbon isotope, 13 The standard value is obtained by correcting C to a constant value and applying decay correction from 1950 AD to the measurement date. 14 This value is used as the C concentration value (100%). The ratio of this value to the value of the sample actually measured is the pMC value.

[0099] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, under normal conditions it will often not reach 100, and will show a value of approximately 110 pMC. On the other hand, regarding chemical substances derived from fossil fuels such as petroleum, 14 When the C concentration is measured, it will show a value of approximately 0 pMC (for example, 0.3 pMC). This value corresponds to the aforementioned biomass ratio of 0%.

[0100] For the reasons stated above, using materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in rubber compositions is preferable from an environmental protection standpoint.

[0101] <Filler> The rubber composition according to this embodiment contains 100 parts by mass or more of silica as a filler per 100 parts by mass of rubber component. The filler preferably contains silica and carbon black, and may consist solely of carbon black and silica.

[0102] (silica) The silica used is not particularly limited, and common types used in the tire industry can be used, such as silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica). The raw material for silica is not particularly limited, and may be a mineral-derived raw material such as quartz, or a biological-derived raw material such as rice husks (for example, silica made from biomass materials such as rice husks), or silica recycled from silica-containing products may be used. Among these, hydrated silica prepared by a wet process is preferred because it contains a large number of silanol groups. These silicas may be used individually or in combination of two or more types.

[0103] Silica derived from biomass materials can be obtained, for example, by extracting silicates from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then using these silicates to react with sulfuric acid in the same way as conventional wet silica, the precipitate of silicon dioxide is filtered, washed with water, dried, and pulverized.

[0104] The silica recycled from silica-containing products can be, for example, silica recovered from products containing silica such as semiconductors and other electronic components, tires, desiccants, and diatomaceous earth and other filter materials. The recovery method is not particularly limited and can include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from semiconductors and other electronic components or tires is preferred.

[0105] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol.6, pp.216-222, etc.).

[0106] Amorphous silica extracted from rice husks can be commercially available from companies such as Wilmar.

[0107] The CTAB specific surface area C of silica is 110 m², from the viewpoint of the effects of the present invention. 2Preferably 140m / g or more. 2 More preferably 170m / g or more. 2 More preferably 190m / g or more. 2 More preferably 200m / g or more. 2 A value of 1 / g or more is particularly preferred. Furthermore, the specific surface area C of the CTAB is 300m². 2 / g or less is more preferable, 280m 2 / g or less is more preferable, 260m 2 A value of less than / g is even more preferable. The CTAB of silica is measured by the measurement method described above.

[0108] The specific surface area (N2SA) of silica for nitrogen adsorption is 110 m², from the viewpoint of the effects of the present invention. 2 Preferably more than / g, 130m 2 More preferably than / g, 150m 2 More preferably than / g, 170m 2 More preferably than / g, 190m 2 More preferably than / g, 210m 2 A value exceeding / g is particularly preferred. Furthermore, the N2SA is 350m 2 Preferably less than / g, 320m 2 Less than / g is more preferable, 280m 2 A value of less than / g is even more preferable. The N2SA of silica is measured by the measurement method described above.

[0109] From the viewpoint of the effects of the present invention, the average primary particle diameter of silica is preferably greater than 8 nm, more preferably greater than 10 nm, and even more preferably greater than 12 nm. Furthermore, the average primary particle diameter is preferably less than 20 nm, more preferably less than 19 nm, even more preferably less than 18 nm, even more preferably less than 17 nm, and particularly preferably less than 16 nm. The average primary particle diameter of silica is measured by the measurement method described above.

[0110] From the viewpoint of the effects of the present invention, the silica content per 100 parts by mass of rubber component is 100 parts by mass or more, preferably 110 parts by mass or more, more preferably 120 parts by mass or more, even more preferably 130 parts by mass or more, and particularly preferably 135 parts by mass or more. Furthermore, from the viewpoint of compatibility with isoprene-based rubber, the silica content is preferably 200 parts by mass or less, more preferably 190 parts by mass or less, and even more preferably 180 parts by mass or less.

[0111] From the viewpoint of the effects of the present invention, the silica content in the filler is preferably 55% by mass or more, more preferably 65% ​​by mass or more, even more preferably 75% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more. Furthermore, from the viewpoint of wear resistance performance, it is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0112] (Carbon Black) The carbon black used is not particularly limited and includes N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw materials for the carbon black may be biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by thermal decomposition of waste tires. The manufacturing method for the carbon black may be combustion such as the furnace method, hydrothermal carbonization (HTC), or thermal decomposition of methane such as the thermal black method. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbia Carbon Corporation, etc. These carbon blacks may be used individually or in combination of two or more types.

[0113] In addition to the above, from the perspective of life cycle assessment, carbon black made from biomass materials such as lignin, or recycled carbon black refined by thermal decomposition of carbon black-containing products such as tires, may also be used as carbon black.

[0114] In this specification, "recycled carbon black" refers to carbon black obtained by crushing used tires and other products containing carbon black, and calcining the crushed material, wherein, according to the thermogravimetric method compliant with JIS K 6226-2:2003, when oxidative combustion occurs by heating in air, the proportion of the mass of ash (ash content), which is the component that does not burn, is 13% by mass or more. In other words, the proportion of the mass (carbon content) lost due to the aforementioned oxidative combustion of recycled carbon black is 87% by mass or less. Recycled carbon black may also be represented as rCB.

[0115] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975, which refers to "Rubber Chemistry and Technology," Vol. 85, No. 3, pp. 408-449 (2012), particularly pp. 438, 440, and 442, states that it can be obtained by the pyrolysis of organic materials at 550-800°C in the absence of oxygen, or by vacuum pyrolysis at relatively low temperatures (

[0027] ). Carbon black obtained from such pyrolysis processes usually lacks functional groups on its surface, as referred to in

[0004] of Japanese Patent Publication No. 6856781 (Comparison of Surface Morphology and Chemistry of Pyrolysis Carbon Black and Commercial Carbon Black, Powder Technology 160 (2005) 190-193).

[0116] Recycled carbon black may lack functional groups on its surface, or it may be treated to include functional groups on its surface. Treatment to include functional groups on the surface of recycled carbon black can be carried out by conventional methods. For example, in European Patent Application Publication No. 3173251, carbon black obtained from a pyrolysis process is treated with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl and / or carboxyl groups on its surface. In addition, in Japanese Patent Publication No. 6856781, carbon black obtained from a pyrolysis process is treated with an amino acid compound containing at least one thiol group or disulfide group to obtain carbon black with an activated surface. The recycled carbon black according to this embodiment also includes carbon black treated to include functional groups on its surface.

[0117] Recycled carbon black can be purchased from companies such as Strable Green Carbon and LD Carbon.

[0118] The nitrogen adsorption specific surface area (N2SA) of carbon black is 70 m² from the perspective of reinforcing properties. 2 Preferably more than / g, 90m 2 More preferably than / g, 110m 2 More preferably than / g, 130m 2 A value exceeding / g is particularly preferred. Furthermore, from the viewpoint of heat generation and processability, 250m 2 Preferably less than / g, 220m 2 Less than / g is more preferable, 190m 2 A value of less than / g is even more preferable. The N2SA of carbon black is measured by the measurement method described above.

[0119] The average primary particle diameter of carbon black is preferably less than 35 nm, more preferably less than 30 nm, even more preferably less than 27 nm, even more preferably less than 23 nm, and particularly preferably less than 19 nm. Furthermore, the average primary particle diameter is preferably greater than 8 nm, more preferably greater than 10 nm, even more preferably greater than 12 nm, and particularly preferably greater than 14 nm. The average primary particle diameter of carbon black is measured by the measurement method described above.

[0120] From the viewpoint of wear resistance, the carbon black content per 100 parts by mass of rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more. Furthermore, the content is preferably less than 50 parts by mass, more preferably less than 40 parts by mass, even more preferably less than 30 parts by mass, even more preferably less than 20 parts by mass, and particularly preferably less than 15 parts by mass.

[0121] (Other fillers) The filler may contain other fillers besides silica and carbon black. These other fillers are not particularly limited, but may include, for example, aluminum hydroxide, calcium carbonate, alumina, clay, talc, and other fillers commonly used in the tire industry. These other fillers may be used individually or in combination of two or more.

[0122] The total filler content F per 100 parts by mass of rubber component is preferably more than 100 parts by mass, more preferably 110 parts by mass or more, even more preferably 120 parts by mass or more, even more preferably 130 parts by mass or more, and particularly preferably 140 parts by mass or more. Furthermore, the content F is preferably 200 parts by mass or less, more preferably 195 parts by mass or less, and even more preferably 190 parts by mass or less.

[0123] <Silane coupling agent> Silica is preferably used in combination with a silane coupling agent. The silane coupling agent is not particularly limited, and any silane coupling agent that has conventionally been used in combination with silica in the tire industry can be used. However, from the standpoint of obtaining the desired effect more favorably, one or more silane coupling agents selected from the group consisting of sulfide-based silane coupling agents and mercapto-based silane coupling agents are preferred, and mercapto-based silane coupling agents are more preferred.

[0124] Examples of sulfide-based silane coupling agents include bis(3-triethoxysilylpropyl) disulfide and bis(3-triethoxysilylpropyl) tetrasulfide. These sulfide-based silane coupling agents may be used individually or in combination of two or more.

[0125] In this specification, mercapto-silane coupling agents refer to silane coupling agents having a mercapto group, and silane coupling agents having a structure in which the mercapto group is protected by a protecting group. Mercapto-silane coupling agents are not particularly limited and include, for example, compounds having a mercapto group represented by the following formula (2), compounds in which a mercapto group represented by the following formula (3) is protected with an ester, and compounds containing bond unit A represented by the following formula (4) and / or bond unit B represented by the following formula (5). Among these, compounds represented by the following formula (3) or compounds containing bond unit A represented by the following formula (4) and / or bond unit B represented by the following formula (5) are preferred, and compounds represented by the following formula (3) are more preferred, in order to better exhibit the effects of the present invention. These mercapto-silane coupling agents may be used alone or in combination of two or more. [ka] [ka] [ka] [ka] (In the formula, x represents an integer greater than or equal to 0; y represents an integer greater than or equal to 1; R 201 R represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms (the alkyl group, alkenyl group, and alkynyl group may be substituted with a halogen atom, hydroxyl group, or carboxyl group); R 202 R represents alkylene with 1 to 30 carbon atoms, alkenylene with 2 to 30 carbon atoms, or alkynylene with 2 to 30 carbon atoms; where R 201 and R 202 (They may form a ring structure.)

[0126] Examples of compounds represented by formula (2) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and compounds represented by the following formula (6). These may be used individually or in combination of two or more. [ka]

[0127] Examples of compounds represented by formula (3) include 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, and 3-octanoylthio-1-propyltrimethoxysilane.

[0128] Compounds containing bond unit A shown in formula (4) and / or bond unit B shown in formula (5) exhibit a suppressed increase in viscosity during processing compared to sulfide-based silane coupling agents such as bis-(3-triethoxysilylpropyl)tetrasulfide. Therefore, silica dispersibility is improved, and it is thought that fuel efficiency, wet grip performance, and elongation at break are further enhanced. This is thought to be because the sulfide portion of bond unit A is a CSC bond, which is thermally more stable than tetrasulfides and disulfides, resulting in less increase in Mooney viscosity.

[0129] The content of bonding unit A is preferably 30 to 99 mol%, and more preferably 50 to 90 mol%, from the viewpoint of suppressing viscosity increase during processing. The content of bonding unit B is preferably 1 to 70 mol%, more preferably 5 to 65 mol%, and even more preferably 10 to 55 mol%. The total content of bonding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. Note that the content of bonding units A and B includes the amount when bonding units A and B are located at the ends of the silane coupling agent. The form in which bonding units A and B are located at the ends of the silane coupling agent is not particularly limited, as long as they form units corresponding to formulas (4) and (5) representing bonding units A and B.

[0130] In a compound containing a bonding unit A represented by formula (4) and a bonding unit B represented by formula (5), the sum of the number of repeats of bonding unit A (x) and the number of repeats of bonding unit B (y) (x+y) is preferably in the range of 3 to 300. Within this range, the mercaptosilane of bonding unit B is converted to the -C7H of bonding unit A. 15 Because it covers the surface, it can suppress the shortening of the scorching time and ensure good reactivity with silica and rubber components.

[0131] Examples of compounds containing the bonding unit A shown in formula (4) and / or the bonding unit B shown in formula (5) include NXT-Z30, NXT-Z45, NXT-Z60, and NXT-Z100 manufactured by Momentive. These may be used individually or in combination of two or more.

[0132] Silane coupling agents other than sulfide-based silane coupling agents and mercapto-based silane coupling agents are not particularly limited and include, for example, vinyl-based silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. These other silane coupling agents may be used individually or in combination of two or more. As the silane coupling agents listed above, for example, silane coupling agents manufactured and sold by Momentive, Evonik Industries, and others can be used.

[0133] The content of the silane coupling agent (preferably one or more silane coupling agents selected from the group consisting of sulfide-based silane coupling agents and mercapto-based silane coupling agents) per 100 parts by mass of silica is preferably 1.0 part by mass or more, more preferably 3.0 parts by mass or more, and even more preferably 5.0 parts by mass or more, from the viewpoint of improving the dispersibility of silica. Furthermore, from the viewpoint of cost and processability, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less.

[0134] <Plasticizer> The rubber composition according to this embodiment contains 20 parts by mass or more of a resin component as a plasticizer per 100 parts by mass of a rubber component. The resin component preferably contains at least one selected from the group consisting of C9 resins, dicyclopentadiene resins, and terpene resins. In addition to the resin component, the plasticizer preferably contains liquid rubber and / or vegetable oil, and may also contain other plasticizers. Examples of other plasticizers include oils other than vegetable oils and ester-based plasticizers. These plasticizers may be derived from mineral resources such as petroleum and natural gas, from biomass, or from naphtha recycled from rubber products or non-rubber products. Alternatively, low molecular weight hydrocarbon components obtained by thermal decomposition and extraction of used tires or products containing various components may be used as plasticizers. The plasticizer may be used alone or in combination of two or more types.

[0135] (Resin components) The rubber composition according to this embodiment may also contain a resin component. The resin component that can be used in this embodiment is not particularly limited, but resins commonly used in the tire industry can be used, such as C9 resins, C5 resins, C5C9 resins, dicyclopentadiene resins, aromatic vinyl resins, coumarone resins, indene resins, terpene resins, rosin resins, phenolic resins, etc. These resin components may be used individually or in combination of two or more. Each resin component may also be used individually or in combination of two or more.

[0136] ≪C9 series resin≫ A "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be a polymer obtained by polymerizing the C9 fraction alone, or a copolymer obtained by copolymerizing the C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) and a C9 fraction is called a DCPD / C9 resin. Furthermore, the C9 resin may be a hydrogenated or modified version of these resins. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene. As for C9 resins, commercially available products from companies such as BASF, Zeon Corporation, and ENEOS Corporation can be used.

[0137] ≪C5 series resin≫ "C5 resins" refer to resins obtained by polymerizing C5 fractions, and may be hydrogenated or modified versions of these resins. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, piperylene, 2-methyl-1-butene, 2-methyl-2-butene, and 1-pentene. As C5 resins, commercially available products from companies such as Structol, Nippon Zeon Co., Ltd., and ENEOS Corporation can be used.

[0138] ≪C5C9 resin≫ "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be hydrogenated or modified. As C5C9 petroleum resin, commercially available products from companies such as Tosoh Corporation and LUHUA can be used.

[0139] <Dicyclopentadiene resins> A "dicyclopentadiene-based resin" refers to a resin in which cyclopentadiene (CPD) and / or dicyclopentadiene (DCPD) are the most abundant monomer components, and these may be hydrogenated or modified resins. Preferred dicyclopentadiene-based resins include polymers obtained by polymerizing only dicyclopentadiene as a monomer, and copolymers (DCPD / C9 resins) obtained by copolymerizing dicyclopentadiene with the C9 fraction. Commercially available dicyclopentadiene-based resins from companies such as ExxonMobil, ENEOS Corporation, Nippon Zeon Corporation, and Maruzen Petrochemical Co., Ltd. can be used.

[0140] Aromatic vinyl resin "Aromatic vinyl resin" refers to a resin in which aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene are the most abundant monomer components, and these may be hydrogenated or modified. As aromatic vinyl resins, α-methylstyrene or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, for reasons of being economical, easy to process, and having excellent heat generation properties. As aromatic vinyl resins, commercially available products from companies such as Kraton, Eastman Chemical Company, and Mitsui Chemicals, Inc. can be used.

[0141] Coumaron-based resin "Coumarone-based resin" refers to a resin containing coumarone as a monomer component, and may be hydrogenated or modified. Preferred coumarone-based resins include, for example, coumarone resin, which is a polymer with coumarone as the monomer component; coumarone-indene resin, which is a copolymer with coumarone and indene as monomer components; and coumarone-indene-styrene resin, which is a copolymer with coumarone, indene, and styrene as monomer components. As coumarone-based resins, commercially available products from companies such as Rutgers, Nippon Paint Chemical Co., Ltd., and Mitsui Chemicals, Inc. can be used.

[0142] Indene resin "Indene-based resin" refers to a resin containing indene as a monomer component, and may be hydrogenated or modified resins. Preferred indene-based resins include, for example, coumarone-indene resin, which is a copolymer of coumarone and indene as monomer components, and coumarone-indene-styrene resin, which is a copolymer of coumarone, indene, and styrene as monomer components. Commercially available indene-based resins from companies such as Rutgers, Nippon Paint Chemical Co., Ltd., and Mitsui Chemicals, Inc. can be used.

[0143] Terpene resins "Terpene resin" refers to a resin containing terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as monomer components, and may be hydrogenated or modified. Preferred terpene resins include, for example, polyterpene resins, which are polymers in which one or more of the aforementioned terpene compounds are used as monomer components; aromatically modified terpene resins, which are copolymers in which the aforementioned terpene compounds and aromatic compounds are used as monomer components; and terpene phenol resins, which are copolymers in which the aforementioned terpene compounds and phenol compounds are used as monomer components. Examples of aromatic compounds that serve as monomer components in aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenol compounds that serve as monomer components in terpene phenol resins include phenol, bisphenol A, cresol, and xylenol. As terpene resins, commercially available products from companies such as Yasuhara Chemical Co., Ltd., Arakawa Chemical Industries, Ltd., and Nippon Terpene Chemical Co., Ltd. can be used.

[0144] ≪Rosin-based resin≫ "Rosin-based resin" refers to a resin containing rosin acid compounds such as abietic acid, neoabietic acid, palastic acid, and isopimal acid, and may be hydrogenated or modified. Rosin-based resins are not particularly limited, but examples include natural resin rosin and rosin-modified resins obtained by hydrogenating, disproportionating, dimerizing, esterifying, etc. As rosin-based resins, commercially available products from companies such as Harima Chemical Industries, Ltd., Arakawa Chemical Industries, Ltd., and IREC Co., Ltd. can be used.

[0145] Phenolic resins "Phenol-based resins" refer to resins containing phenol compounds such as phenol and cresol as monomer components, and may also be hydrogenated or modified resins. Phenolic resins are not particularly limited, but examples include phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, oil-modified phenol-formaldehyde resins, and terpene-phenol resins. Phenolic resins that are commercially available from companies such as Sumitomo Bakelite Co., Ltd., DIC Corporation, and Asahi Organic Materials Co., Ltd. can be used.

[0146] Liquid resin The resin component may be a liquid resin that is in a liquid state at 25°C. The liquid resin is not particularly limited, but examples include liquid aromatic vinyl resins, liquid C9 resins, liquid C5C9 resins, and liquid coumarone-indene resins. These liquid resins may be used individually or in combination of two or more.

[0147] The weight-average molecular weight (Mw) of the liquid resin is usually less than 10,000, preferably 9,000 or less, more preferably 6,000 or less, and even more preferably 4,500 or less. Furthermore, the Mw of the liquid resin is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, even more preferably 1,500 or more, and particularly preferably 2,000 or more.

[0148] From the viewpoint of wet grip performance, the softening point of the resin component is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher. Furthermore, from the viewpoint of processability and improved dispersibility between the rubber component and filler, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower. The softening point of the resin component is measured by the measurement method described above.

[0149] The content of the resin component (total amount if multiple resin components are used in combination) per 100 parts by mass of the rubber component is 20 parts by mass or more, preferably 30 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 55 parts by mass or more. On the other hand, from the viewpoint of suppressing heat generation, the content is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less.

[0150] The total content of C9 resin, dicyclopentadiene resin, and terpene resin per 100 parts by mass of rubber component is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more. On the other hand, from the viewpoint of suppressing heat generation, the content is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 80 parts by mass or less.

[0151] (oil) Examples of oils include mineral oil, vegetable oil, and animal oil. Furthermore, from a life cycle assessment perspective, waste oil from rubber mixers and engines, or refined waste cooking oil from restaurants, may also be used. Oils may be used individually or in combination of two or more types.

[0152] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oils (mineral oil), naphthenic oils, and aromatic oils. Specific examples of mineral oil include MES (Mild Extracted Solvate), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract). Furthermore, for environmental reasons, oils with a low content of polycyclic aromatic compounds (PCA) can be used. Examples of low-PCA oils include MES, TDAE, and heavy naphthenic oils. Mineral oil may be used alone or in combination of two or more types.

[0153] In this specification, vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and wood wax. Furthermore, vegetable oils may also include refined oils (such as salad oil) obtained by refining the above oils, transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidized polymerized oils obtained by oxidizing the above oils, and waste cooking oils recovered from use as edible oils. Note that vegetable oils may be liquid or solid at 25°C. Vegetable oils may be used individually or in combination of two or more types.

[0154] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin and a fatty acid are ester-bonded. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer of three or more. Note that acylglycerols of two or more forms can be obtained by thermal polymerization, oxidative polymerization, etc. Also, the acylglycerol may be a liquid or a solid at 25°C.

[0155] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, 1 This can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, it is measured at room temperature. 1 When 1H-NMR was measured and the tetramethylsilane (TMS) signal was set to 0.00 ppm, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm. These signals are presumed to originate from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0156] The aforementioned fatty acids are not particularly limited and may be unsaturated or saturated fatty acids. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0157] In particular, it is desirable that the fatty acid contains fatty acids with few double bonds, i.e., saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As a vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids may be used, or a vegetable oil that has been modified by transesterification or other means may be used. Furthermore, in order to produce a vegetable oil containing such fatty acids, plants may be improved by breeding, genetic modification, genome editing, etc.

[0158] As for vegetable oils, commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Ltd. can be used.

[0159] Examples of animal oils include fish oil, beef tallow, whale oil, or oleyl alcohol which can be derived from them.

[0160] The content of unsaturated fatty acids in the constituent fatty acids of vegetable oil is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 75% by mass or more, even more preferably 80% by mass or more, and particularly preferably 85% by mass or more.

[0161] When vegetable oil is included, the content of the rubber component per 100 parts by mass is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more, from the viewpoint of the effects of the present invention. Furthermore, the content is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less.

[0162] When oil is included, the content per 100 parts by mass of rubber component (total amount if multiple oils are used in combination) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more, from the viewpoint of the effects of the present invention. Furthermore, the content is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less.

[0163] (Liquid rubber) Liquid rubber is not particularly limited as long as it is a polymer that is in a liquid state at 25°C, but examples include liquid butadiene rubber (liquid BR), liquid styrene butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene isoprene rubber (liquid SIR), and liquid farnesene rubber. These liquid rubbers may be used individually or in combination of two or more.

[0164] The weight-average molecular weight (Mw) of liquid rubber is usually less than 10,000, preferably 9,000 or less, more preferably 6,000 or less, and even more preferably 4,500 or less. Furthermore, the Mw of liquid rubber is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, even more preferably 1,500 or more, and particularly preferably 2,000 or more. When the Mw of liquid rubber is within the above range, the effects of the present invention tend to be better obtained. Note that in this specification, liquid rubber is not included in the above rubber components.

[0165] When liquid rubber is included, the content of the rubber component per 100 parts by mass is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, and particularly preferably 10 parts by mass or more, from the viewpoint of the effects of the present invention. Furthermore, the content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0166] (Ester-based plasticizers) Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di-2-ethylhexyl azelaate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), and trixylenyl phosphate (TXP). Ester-based plasticizers may be used individually or in combination of two or more.

[0167] From the viewpoint of wet grip performance, the content of plasticizers per 100 parts by mass of rubber components (total amount if multiple plasticizers are used in combination) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more. From the viewpoint of processability, it is preferably 150 parts by mass or less, more preferably 140 parts by mass or less, even more preferably 130 parts by mass or less, and particularly preferably 120 parts by mass or less.

[0168] <Anti-aging agent> The anti-aging agents are not particularly limited, but include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), and N,N'-ditril-p-phenylenediamine. Examples include p-phenylenediamine-based antioxidants such as amines (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); 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. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., Flexis, and others. The antioxidant may be used alone or in combination of two or more.

[0169] When an anti-aging agent is included, the content of the anti-aging agent per 100 parts by mass of the rubber component (total amount if multiple anti-aging agents are used in combination) is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, even more preferably 3.5 parts by mass or more, and particularly preferably 4.0 parts by mass or more. Furthermore, the content is preferably 10 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 6.0 parts by mass or less.

[0170] <Other compounding agents> In addition to rubber components and fillers, the rubber composition according to this embodiment may appropriately contain compounding agents commonly used in the tire industry, such as vulcanized rubber particles, processing aids, waxes, stearic acid, zinc oxide, vulcanizing agents, and vulcanization accelerators.

[0171] (Vulcanized rubber particles) Vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the viewpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These vulcanized rubber particles may be used individually or in combination of two or more types.

[0172] The vulcanized rubber particles are not particularly limited and may be either unmodified or modified vulcanized rubber particles. Commercially available vulcanized rubber products can be used, for example, those from Lehigh, Muraoka Rubber Industries, and others.

[0173] When vulcanized rubber particles are included, the content per 100 parts by mass of the rubber component can be appropriately adjusted, for example, within a range of more than 1 part by mass and less than 80 parts by mass.

[0174] (Processing aid) Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, fatty acid esters, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. For example, commercially available processing aids from companies such as Schill+Seilacher and Performance Additives can be used. These processing aids may be used individually or in combination of two or more.

[0175] When processing aids are included, the content per 100 parts by mass of rubber components is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass, from the viewpoint of exhibiting an effect of improving processability. Furthermore, from the viewpoint of abrasion resistance and fracture strength, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass.

[0176] (wax) The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used, such as mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. The wax according to this embodiment does not contain stearic acid. The wax can be commercially available from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Paramelt Co., Ltd. These waxes may be used individually or in combination of two or more types.

[0177] When wax is included, the amount of wax per 100 parts by mass of rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass, from the viewpoint of weather resistance of the rubber. Furthermore, from the viewpoint of preventing whitening of the tire due to bloom, it is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass.

[0178] (Stearic acid) When stearic acid is included, its content per 100 parts by mass of rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass, from the viewpoint of processability. Furthermore, from the viewpoint of vulcanization rate, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass.

[0179] (Zinc oxide) When zinc oxide is included, its content per 100 parts by mass of rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass, from the viewpoint of processability. Furthermore, from the viewpoint of wear resistance, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass.

[0180] (Vulcanizing agent) Sulfur is preferably used as a vulcanizing agent. Suitable sulfur varieties include powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur.

[0181] When sulfur is included as a vulcanizing agent, the amount of sulfur per 100 parts by mass of rubber component is preferably more than 0.1 parts by mass, more preferably more than 0.5 parts by mass, and even more preferably more than 1.0 part by mass, from the viewpoint of ensuring a sufficient vulcanization reaction. Furthermore, from the viewpoint of preventing deterioration, it is preferably less than 5.0 parts by mass, more preferably less than 3.0 parts by mass, and even more preferably less than 2.0 parts by mass. When oil-containing sulfur is used as the vulcanizing agent, the amount of vulcanizing agent shall be the total amount of pure sulfur contained in the oil-containing sulfur.

[0182] As a vulcanizing agent other than sulfur, known organic crosslinking agents can also be used. The organic crosslinking agent is not particularly limited as long as it can form crosslinking chains other than polysulfide bonds, but examples include alkylphenol-sulfur chloride condensates, hexamethylene-1,6-bisthiosulfate sodium dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and dicumyl peroxide. These organic crosslinking agents can be commercially available from companies such as Taoka Chemical Industries, Ltd., Lanxess Corporation, and Flexis.

[0183] (Vulcanization accelerator) The vulcanization accelerator is not particularly limited, but examples include sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiram-based vulcanization accelerators, thiourea-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, imidazoline-based vulcanization accelerators, xanthate-based vulcanization accelerators, caprolactam disulfide, and the like. These vulcanization accelerators may be used individually or in combination of two or more. Among these, one or more vulcanization accelerators selected from the group consisting of sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, and guanidine-based vulcanization accelerators are preferred because they more favorably produce the desired effect.

[0184] Examples of sulfenamide-based vulcanization accelerators include N-tert-butyl-2-benzothiazolyl sulfenamide (TBBS), N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazolyl sulfenamide (DCBS).

[0185] Examples of thiazole-based vulcanization accelerators include 2-mercaptobenzothiazole (MBT) or its salts, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinothio)benzothiazole. Of these, MBTS and MBT are preferred, with MBTS being more preferred.

[0186] Examples of guanidine-based vulcanization accelerators include 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salts of dicatecholborate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, and 1,3-di-o-cumenyl-2-propionylguanidine.

[0187] When a vulcanization accelerator is included, the content per 100 parts by mass of the rubber component (total amount if multiple vulcanization accelerators are used in combination) is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, and particularly preferably 4.0 parts by mass or more, from the viewpoint of ensuring a sufficient vulcanization rate. Furthermore, the content of the vulcanization accelerator is preferably 10 parts by mass or less, and more preferably 7.0 parts by mass or less, from the viewpoint of suppressing blooming.

[0188] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. Methods for obtaining these materials from carbon dioxide include directly converting carbon dioxide, or converting methane obtained through a methanation process in which methane is synthesized from carbon dioxide.

[0189] [Manufacturing] The rubber composition according to this embodiment can be manufactured by known methods. For example, it can be manufactured by kneading each of the above components using a rubber kneading device such as an open roll or a closed kneader (Banbury mixer, kneader, etc.).

[0190] The mixing process includes, for example, a base mixing process in which compounding agents and additives other than the vulcanizing agent and vulcanization accelerator are mixed, and a final mixing (F mixing) process in which the vulcanizing agent and vulcanization accelerator are added to the mixture obtained in the base mixing process and mixed. Furthermore, the base mixing process can be divided into multiple processes as desired. When dividing the base mixing process, the method may be (1) a method in which some of the compounding agents and additives are mixed in advance to form a masterbatch, and then the remaining compounding agents and additives are added to the resulting masterbatch and mixed, or (2) a method in which all the compounding agents and additives to be mixed in the base mixing process are mixed at once, and then the mixture is remilled one or more times. In the method of (1) above, the number of masterbatches is not limited and may be two or more. Also, when the number of masterbatches is two or more, all the compounding agents and additives used in the base mixing process may be allocated to one of the masterbatches.

[0191] There are no particular limitations on the mixing conditions, but for example, in the base mixing process, mixing is performed at a discharge temperature of 150-170°C for 3-10 minutes, and in the final mixing process, mixing is performed at 70-110°C for 1-5 minutes. There are no particular limitations on the vulcanization conditions, but for example, vulcanization is performed at 150-200°C for 10-30 minutes.

[0192] The tire according to this embodiment, having a tread made of the aforementioned rubber composition, can be manufactured by conventional methods. Specifically, the tire can be manufactured by extruding an unvulcanized rubber composition, prepared by blending the above components with the rubber component as needed, into the shape of a tread; forming an unvulcanized tire by bonding and molding the resulting tread together with other tire components on a tire molding machine using conventional methods; and then heating and pressurizing the resulting unvulcanized tire in a vulcanizing machine. The vulcanization conditions are not particularly limited, and for example, a method of vulcanizing at 150 to 200°C for 10 to 30 minutes can be used.

[0193] [Application] The tire according to this embodiment can be used for any application, regardless of whether it is a pneumatic or non-pneumatic tire, and can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a racing tire, a motorcycle tire, a heavy-duty tire, or a run-flat tire. A passenger car tire is a tire intended to be mounted on a four-wheeled vehicle and has a maximum load capacity of less than 1400 kg. A heavy-duty tire is a tire with a maximum load capacity of 1400 kg or more. In addition, the tire according to this embodiment can be used as an all-season tire, a summer tire, or a winter tire such as a studless tire. [Examples]

[0194] The following examples (case studies) are shown as preferred for implementation, but the scope of the present invention is not limited to these examples. The tires obtained using the various chemicals shown below, according to Tables 1-1 to 2, were examined, and the results calculated based on the evaluation method below are shown in Tables 1-1 to 2.

[0195] <Various chemicals> The various chemicals used in the examples and comparative examples are summarized below. IR-type rubber: TSR20(NR) SBR1: Toughden 2000R (S-SBR, styrene content: 25% by mass, vinyl content: 13 mol%, Tg: -65℃, non-oil-based) manufactured by Asahi Kasei Corporation. SBR2: F1810 manufactured by LGCHEM (S-SBR, styrene content: 18% by mass, vinyl content: 10 mol%, Tg: -73℃, contains 5.0 parts by mass of oil-expanding oil per 100 parts by mass of rubber solids) BR: UBEPOL BR (registered trademark) 150B manufactured by UBE Corporation (unmodified BR, cis content: 97 mol%, Mw: 440,000) Carbon Black 1: Show Black N134 (N2SA: 148ml) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 18nm) Carbon Black 2: Show Black N220 (N2SA: 115m) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 22nm) Silica 1: UltraSil 9100GR (CTAB specific surface area: 200 m²) manufactured by Evonik Industries 2 / g, N2SA:235m 2 / g) Silica 2: Solvay's Zeosil Premium SW (CTAB specific surface area: 245 m²) 2 / g, N2SA:258m 2 / g) Silane coupling agent 1: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Industries. Silane coupling agent 2: NXT (3-octanoylthio-1-propyltriethoxysilane) manufactured by Evonik Industries. Resin component 1: SYLVATRAXX4401 manufactured by Kraton (a copolymer of α-methylstyrene and styrene, softening point: 85°C) Resin component 2: SYLVATARAXX4150 (polyterpene resin, softening point: 115°C) manufactured by Kraton Corporation. Resin component 3: ExxonMobil's Oppera PR383 (hydrogenated DCPD / C9 resin, softening point: 103°C) Oil 1: VivaTec500 (TDAE oil) manufactured by H&R Co., Ltd. Oil 2: Sunflower oil manufactured by Nisshin Oillio Group Ltd. (Oleic acid content in constituent fatty acids: 55% by mass, total content of polyunsaturated fatty acids in constituent fatty acids: 8% by mass) Liquid resin: Ricon340 (liquid C5C9 resin, Mw: 2400) manufactured by Clay Valley Corporation. Wax: Ozoace 0355 (paraffin wax) manufactured by Nippon Seiro Co., Ltd. Anti-aging agent 1: Nocrack 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent 2: Nocrack RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Co., Ltd. Processing aid: WB16 (a mixture of calcium soap and fatty acid amide) manufactured by Structol. Stearic acid: Beads of stearic acid manufactured by NOF Corporation Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator 1: Noxellar CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noxellar D (1,3-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0196] (Examples and Comparative Examples) According to the formulations shown in Tables 1-1 to 1-2, chemicals other than sulfur and vulcanization accelerators were mixed in a 1.7 L sealed Banbury mixer at a discharge temperature of 160°C for 4 minutes to obtain a mixture. Next, using an open roll mixer, sulfur and vulcanization accelerators were added to the mixture and mixed for 4 minutes until the temperature reached 105°C to obtain an unvulcanized rubber composition. Using the obtained unvulcanized rubber composition, it was molded to the shape of the tread and bonded together with other tire components to produce an unvulcanized tire, which was then vulcanized at 170°C to obtain each test tire. Maximum load capacity W of the tires (tire size: 205 / 65R15) in Tables 1-1 to 1-3 L The weight is 660kg, the tire weight G is 8.4kg, G / W L The value is 0.0127. Table 2 shows the maximum load capacity W of the tire (tire size: 175 / 65R14). L The weight is 515kg, the tire weight G is 6.5kg, G / W L It is 0.0126.

[0197] <Measurement of acetone extraction amount (AE)> The amount of acetone extracted AE is measured for each rubber test piece, which is prepared by cutting it from the tread of each test tire. The amount of acetone extracted AE is calculated by immersing each rubber test piece in acetone for 72 hours to extract soluble components, measuring the mass of each test piece before and after extraction, and using the following formula. Acetone extraction amount AE (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0198] <Wet grip performance> Each test tire is mounted on one of the four wheels of a 2000cc front-wheel-drive passenger car, and the braking distance is measured on a wet asphalt surface from the point where the brakes are applied at a speed of 100 km / h. The braking distance of the tire of the standard comparative example (Comparative Example 1 in Tables 1-1 to 1-3, and Comparative Example 4 in Table 2) is set to 100, and the wet grip performance of each tire is expressed as an index using the following formula. A higher index indicates better wet grip performance. (Wet Grip Performance Index) = (Braking distance of the standard comparison tire) / (Braking distance of each test tire) × 100

[0199] <Handling stability performance at high speeds> Each test tire is mounted on all wheels of a vehicle (domestic FF 2000cc), and the vehicle is driven 10 times on a dry asphalt test course at approximately 120 km / h. Twenty test drivers then provide subjective evaluations of the instability during cornering, entry, and exit. The evaluation is given as an integer value from 1 to 5 points (higher scores indicate less instability), and the total scores of the 20 test drivers are calculated. The total scores of the reference comparison (Reference Comparison 1 in Tables 1-1 to 1-3, and Reference Comparison 4 in Table 2) are converted to a baseline value (100), and the evaluation results of each test tire are indexed and displayed in proportion to the total score. A higher numerical value indicates better handling stability at high speeds.

[0200] <Overall Performance> The sum of the above wet grip performance index and the handling stability performance index at high speeds is shown as the overall performance index.

[0201]

Table 1-1

[0202]

Table 1-2

[0203]

Table 1-3

[0204]

Table 2

[0205] <Embodiment> Examples of embodiments of the present invention are shown below.

[0206] [1] A tire having a tread, wherein the tread has one or more circumferential grooves, the tread is composed of a rubber composition containing a rubber component, a filler, and a resin component, the rubber component contains 40% by mass or more of an isoprene-based rubber and more than 40% by mass of a styrene-butadiene rubber, the filler contains silica, the rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of a resin component with respect to 100 parts by mass of the rubber component, when the land ratio of the tread is R and the total content of the filler with respect to 100 parts by mass of the rubber component in the rubber composition is F (parts by mass), a tire in which R×F is more than 65, preferably more than 70 and less than 130. [2] The tire according to [1] above, wherein the rubber composition contains 130 parts by mass or more of silica with respect to 100 parts by mass of the rubber component. [3] The tire according to [1] or [2] above, wherein the CTAB specific surface area C of the silica is 190 m 2 / g or more. [4] The tire according to any one of [1] to [3] above, wherein the rubber composition contains 50 parts by mass or more of a resin component with respect to 100 parts by mass of the rubber component. [5] The tire according to any one of [1] to [4] above, wherein the styrene content of the styrene-butadiene rubber is 20% by mass or less. [6] The tire according to any one of [1] to [5] above, wherein the amount of acetone extracted from the rubber composition AE (mass%) is 25.0 or more. [7] The tire according to any one of [1] to [6] above, wherein the resin component contains at least one selected from the group consisting of C9 resins, dicyclopentadiene resins, and terpene resins. [8] The tire according to any one of [1] to [7] above, wherein the rubber composition further contains a mercapto-silane coupling agent. [9] The tire according to any one of [1] to [8] above, wherein the resin component contains a liquid resin.

[10] The tire according to any one of [1] to [9] above, wherein the rubber composition contains liquid rubber.

[11] The tire according to any one of [1] to

[10] above, wherein the rubber composition further contains vegetable oil.

[12] The tire according to any of [1] to

[11] above, wherein when the amount of acetone extracted from the rubber composition is AE (mass%), F × AE is greater than 3500.

[13] The tire according to any of [1] to

[12] above, wherein when the amount of acetone extracted from the rubber composition is AE (mass%), R × AE is greater than 15.

[14] The CTAB specific surface area of ​​the silica is C(m 2 If / g, then the tire is one of the tires listed in any of [1] to

[13] above, where R×C is greater than 150.

[15] The maximum load capacity of the tire is W L (kg), if the weight of the tire is G (kg), then G / W L A tire according to any of the above [1] to

[14] , wherein the ratio is 0.0170 or less, preferably 0.0150 or less, and more preferably 0.0140 or less. [Explanation of Symbols]

[0207] 1. Tread surface 2. Center Track and Field Club 3 Shoulder Track and Field Club 4 Circumferential groove 5, 6, 7, 8 Width groove 9. Grooves that connect to circumferential grooves at both ends. C Tire circumferential direction W (Tire width direction) CL Tire Equator Te tread edge

Claims

1. A tire having a tread, The tread has one or more circumferential grooves, The tread is composed of a rubber composition containing rubber components, fillers, and resin components. The aforementioned rubber component contains 40% by mass or more of isoprene-based rubber and more than 40% by mass of styrene-butadiene rubber. The filler contains silica, The rubber composition contains 100 parts by mass or more of silica and 20 parts by mass or more of resin components per 100 parts by mass of the rubber component. When the land ratio of the tread is R, and the total content of filler in the rubber composition relative to 100 parts by mass of the rubber component is F (parts by mass), Tires with an R×F ratio of over 65.

2. The tire according to claim 1, wherein the rubber composition contains 130 parts by mass or more of silica per 100 parts by mass of the rubber component.

3. The CTAB specific surface area C of the aforementioned silica is 190 m². 2 A tire according to claim 1 or 2, wherein the weight is 1 / g or more.

4. The tire according to claim 1 or 2, wherein the rubber composition contains 50 parts by mass or more of a resin component with respect to 100 parts by mass of the rubber component.

5. The tire according to claim 1 or 2, wherein the styrene content of the styrene-butadiene rubber is 20% by mass or less.

6. The tire according to claim 1 or 2, wherein the acetone extract amount AE (mass%) of the rubber composition is 25.0 or more.

7. The tire according to claim 1 or 2, wherein the resin component contains at least one selected from the group consisting of C9 resins, dicyclopentadiene resins, and terpene resins.

8. The tire according to claim 1 or 2, wherein the rubber composition further contains a mercapto-silane coupling agent.

9. The tire according to claim 1 or 2, wherein the resin component contains a liquid resin.

10. The tire according to claim 1 or 2, wherein the rubber composition contains liquid rubber.

11. The tire according to claim 1 or 2, wherein the rubber composition further contains vegetable oil.

12. When the amount of acetone extracted from the rubber composition is AE (mass%), A tire according to claim 1 or 2, wherein F×AE is greater than 3500.

13. When the amount of acetone extracted from the rubber composition is AE (mass%), A tire according to claim 1 or 2, wherein R×AE is greater than 15.

14. The CTAB specific surface area of ​​the silica is C(m 2 If you use / g, A tire according to claim 1 or 2, wherein R×C is greater than 150.

15. The maximum load capacity of the aforementioned tire is W L (kg), if the weight of the tire is G (kg), then G / W L The tire according to claim 1 or 2, wherein the coefficient is 0.0170 or less.

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