Tire

Abstract

To provide a tire improved in low fuel consumption performance.SOLUTION: A tire comprising at least one tire member composed of a rubber composition containing recycled carbon black, wherein A, B, Wt and Dt simultaneously satisfy the following formula (1) and formula (2), where A is a thickness (mm) of the tire member, B is a total content (parts by mass) of carbon black contained in the rubber composition, Wt is a cross-sectional width (mm) of the tire, and Dt is an outer diameter (mm) of the tire: (π / 4) * (Dt2 / Wt) ≥ 1700 (1) (Dt2 / Wt) / (B * A)> 20 (2) SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] From the viewpoint of environmental issues and resource conservation, studies are being conducted on energy conservation in tires as well. For example, Patent Document 1 describes a tire in which fuel economy and other performance are improved by setting the tire weight, tire size, and tan δ of the rubber composition constituting the tread within predetermined ranges relative to the tire's maximum load capacity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 074932 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a tire with improved fuel economy performance. [Means for solving the problem]

[0005] The present invention provides a tire having at least one tire component made from a rubber composition containing recycled carbon black, The present invention relates to a tire in which A, B, Wt, and Dt simultaneously satisfy the following formulas (1) and (2), where A is the thickness (mm) of the tire component, B is the total content (parts by mass) of carbon black contained in the rubber composition, Wt is the cross-sectional width (mm) of the tire, and Dt is the outer diameter (mm) of the tire. (1) (π / 4)×(Dt 2 / Wt)≧1700 (2) (Dt 2 / Wt) / (B×A)>20 [Effects of the Invention]

[0006] According to the present invention, a tire with improved fuel economy performance can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic view showing a portion of a cross section (upper right portion of the cross section) taken along the tire meridian in a tire according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the tire cross-sectional width Wt and tire outer diameter Dt in a tire cross section. [Figure 3] 1 is a plan view showing a contact surface of a tread of a tire according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] A tire according to an embodiment of the present invention has at least one tire component made of a rubber composition containing recycled carbon black, wherein A, B, Wt, and Dt simultaneously satisfy the following formulas (1) and (2), where A is the thickness (mm) of the tire component, B is the total content (parts by mass) of carbon black contained in the rubber composition, Wt is the cross-sectional width (mm) of the tire, and Dt is the outer diameter (mm) of the tire. (1) (π / 4)×(Dt 2 / Wt)≧1700 (2) (Dt 2 / Wt) / (B×A)>20

[0009] While not intending to be bound by theory, the reasons why fuel economy can be improved in this embodiment are believed to be as follows. (1) By satisfying the predetermined relationship between the tire outer diameter Dt and the tire cross-sectional width Wt as expressed by formula (1) and reducing the contact width of the tread portion relative to the surface area of ​​the tire sidewall, (a) heat generation resulting from friction between the tire and the road surface is reduced, thereby suppressing temperature increases due to heat generation in the tread portion. (b) Because the tire sidewall is large, heat dissipation is facilitated throughout the tire, preventing excessive increases in the tire temperature and the sidewall temperature. (c) This is believed to reduce rolling resistance. Furthermore, (2) Because recycled carbon black absorbs moisture more than regular carbon black, the inclusion of recycled carbon black is believed to facilitate the release of heat generated when the recycled carbon black interacts with the rubber component. (3) By thinning the tire components (i.e., reducing the value of A of the tire components) and reducing the carbon black content of the rubber composition (i.e., reducing B), and thereby satisfying formula (2), it is believed that both heat accumulation and heat generation in the tire can be suppressed. It is believed that the above (1) to (3) work together to improve the fuel economy performance of the tire.

[0010] The at least one tire component made of the rubber composition containing the recycled carbon black is preferably at least one tire component selected from a base tread, a sidewall, a clinch apex, an insulation, and an inner liner.

[0011] It is believed that by using a rubber composition containing recycled carbon black in these tire components, the tire components' heat generation and heat storage properties are reduced, and their heat dissipation properties are improved, resulting in improved fuel economy.

[0012] The right side of formula (1) is preferably 1800.

[0013] Tires that satisfy stricter conditions of formula (1) are considered to have even better fuel efficiency.

[0014] The right side of formula (2) is preferably 23.

[0015] Tires that satisfy stricter conditions of formula (2) are considered to have even better fuel efficiency.

[0016] It is preferable that at least one tire component made of a rubber composition containing the recycled carbon black is a base tread, that the rubber composition constituting the base tread contains an isoprene-based rubber and a butadiene rubber, and that the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass.

[0017] It is preferable that at least one tire component made of a rubber composition containing the recycled carbon black is a sidewall, the rubber composition constituting the sidewall contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80 mass%.

[0018] It is preferable that at least one tire component made of the rubber composition containing the recycled carbon black is a clinch apex, the rubber composition constituting the clinch apex contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80 mass%.

[0019] It is preferable that at least one tire component made of a rubber composition containing the recycled carbon black is insulation, that the rubber composition constituting the insulation contains an isoprene-based rubber and a styrene-butadiene rubber, and that the total content of the isoprene-based rubber and the styrene-butadiene rubber exceeds 80 mass%.

[0020] It is preferable that at least one tire component made of a rubber composition containing the recycled carbon black is an inner liner, the rubber composition constituting the inner liner contains a butyl-based rubber, and the content of the butyl-based rubber is more than 90 mass%.

[0021] It is preferable that the tire has two or more circumferential main grooves extending circumferentially on the tread surface of the tire, a pair of shoulder land portions on the outer side in the tire width direction defined by a pair of outermost circumferential main grooves located on the outermost sides in the tire width direction among the circumferential main grooves, and a center land portion sandwiched between the pair of shoulder land portions, and that the negative ratio of the center land portion is greater than 0% and less than 15%.

[0022] By setting the negative ratio of the center land area to a predetermined ratio, the contact area of ​​the tread portion is limited, heat generation due to friction with the road surface is reduced, and fuel economy is thought to be improved.

[0023] The negative ratio of the shoulder land portion is preferably more than 20%.

[0024] It is believed that by reducing the negative ratio of the shoulder land area and further reducing the contact area, heat generation due to friction with the road surface will be reduced, improving fuel efficiency.

[0025] The total amount of styrene (mass %) in the rubber component contained in the rubber composition is preferably less than 2.0.

[0026] A low total styrene content also reduces the amount of styrene unit domain formation, which is thought to result in higher rigidity and lower rolling resistance.

[0027] The content of silica contained in the rubber composition is preferably less than 10 parts by mass per 100 parts by mass of the rubber component.

[0028] It is believed that rigidity increases in the small deformation region, reducing rolling resistance.

[0029] The rubber composition preferably contains a resin.

[0030] Preferably, the tire is for an electric vehicle.

[0031] The above tires are expected to have excellent fuel efficiency and a long driving distance on a single charge.

[0032] <Definition> "Normal condition" means that the tire is mounted on a normal rim, inflated to the normal internal pressure, and unloaded. Unless otherwise specified, the tire must be in its normal condition.

[0033] Unless otherwise specified, the "dimensions of each part of the tire" are values ​​that are specified when the tire appears on its outer surface in a normal state, while those that exist inside the tire or on a cut surface of the tire are values ​​that are specified when, for example, the tire is cut along a plane that includes the tire rotation axis and the cut tire piece is maintained within the rim width of a normal rim.

[0034] "Genuine rim" refers to the rim specified for each tire in the standard system that includes the standard on which the tire is based. 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 Organization), 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." JATMA, ETRTO, and TRA are referenced in that order, and if an applicable size is available at the time of reference, that standard is followed. In the case of a tire not specified in the above standards, it refers to the narrowest rim among the smallest diameter rims that can be mounted on the tire and can maintain internal pressure (i.e., no air leaks from between the rim and tire).

[0035] "Normal internal pressure" refers to the air pressure specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA, it is "maximum air pressure," for ETRTO, it is "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 follow that standard if there is an applicable size at the time of reference. In the case of tires not specified in the above standards, it refers to the normal internal pressure (250kPa or more) of another tire size (defined in the standard) that is specified using the regular rim as the standard rim, and if there are multiple normal internal pressures of 250kPa or more listed, it refers to the smallest value among them.

[0036] "Normal load (kg)" is the load specified for each tire in the standard system including the standard on which the tire is based, for example, "Maximum Load Capacity" for JATMA, "Load Capacity" for ETRTO, and the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA. As with normal rims and normal internal pressures, JATMA, ETRTO, and TRA should be referenced in that order, and if there is an applicable size at the time of reference, that standard should be followed. For tires not specified in the above standards, the maximum load capacity W calculated separately should be used. L is the normal load.

[0037] "Maximum load capacity W L (kg)" is calculated using the following formula: "V" is the virtual volume of the tire (mm 3), "Dt" is the outer diameter (mm) of the tire in its normal state, "Ht" is the tire's cross-sectional height (mm) in the tire's radial direction in a cross section of the tire taken along a plane including the tire's rotation axis, and "Wt" is the tire's cross-sectional width (mm) in its normal state. Ht can be calculated by (Dt-R) / 2, where R is the tire rim diameter. Wt is the value obtained by excluding any patterns or letters on the tire sidewall. Note that maximum load capacity is synonymous with the normal load mentioned above.

[0038]

number

[0039] "Tire outer diameter Dt" refers to the outer diameter of the tire in its normal state.

[0040] "Tire section width Wt" refers to the maximum width between the outer surfaces of the sidewalls in the normal state (excluding any patterns or letters on the side of the tire).

[0041] "Tire cross-sectional height Ht" refers to the radial height of the tire in a cross section of the tire taken along a plane including the tire rotation axis, and corresponds to half the difference between the tire's outer diameter Dt and the rim diameter R, where R is the tire rim diameter. In other words, the cross-sectional height Ht can be calculated by (Dt-R) / 2.

[0042] "Weight of tire" refers to the weight of the tire itself, excluding the weight of the rim. On the other hand, if the tire has components such as sponge or sealant, or sensor components, the weight includes these components.

[0043] The "land portion" refers to the portion of the tread that comes into contact with the ground when the tire is pressed against the ground, and is the portion of the tread that constitutes the effective contact area.

[0044] A "groove" is a recess formed on the tread surface of a tire (extending radially inward) with an opening width of 2.0 mm or more on the tread surface. A groove with an opening width of less than 2.0 mm is called a "sipe."

[0045] A "circumferential groove" refers to a groove that extends continuously in the circumferential direction of the tire. A circumferential groove may extend linearly along the circumferential direction, or may extend in a wavy, sinusoidal, or zigzag pattern along the circumferential direction. A "circumferential main groove" refers to a circumferential groove with a groove width of 4 mm or more.

[0046] "Groove width" means the length between groove edges on the tread surface in a cross section of the tire taken along a plane including the tire axis of rotation.

[0047] The "tread portion" refers to a component that includes the portion that forms the tire's contact surface, and in the case where the tire includes components that form the tire skeleton from steel or textile materials, such as a belt layer, a belt reinforcing layer, and a carcass layer, the "tread portion" is a component that is located radially outward of these components in the tire radial cross section.

[0048] The "negative rate" is the ratio (%) of the groove area to the contact area of ​​a given region of the tread contact patch. The negative rate is calculated as the ratio (%) of the groove area in each land portion to the center land portion and shoulder land portion within the tread contact patch. Specifically, a tire is mounted on a standard rim, pressurized to the standard internal pressure, and left at 25°C for 24 hours. After that, ink is applied to the tire tread surface, and the tire is pressed against cardboard under a standard load (camber angle 0°). The area of ​​the contact shape of each of the center land portion and shoulder land portion is measured (this is called the area of ​​the transferred land shape). In addition, the area of ​​the shape obtained by smoothly connecting the contact shape contours of each of the center land portion and shoulder land portion is calculated, and this is considered the total area of ​​each land portion (this is called the total area of ​​the land shape obtained by connecting the transferred contours). The negative rate for each of the center land portion and shoulder land portion is calculated as [1 - (area of ​​the transferred land shape) / (total area of ​​the land shape obtained by connecting the transferred contours)] × 100 (%).

[0049] "Base tread thickness" refers to the thickness of the rubber layer measured along a normal to the tire equator in a cross section of the tire taken along a plane including the tire rotation axis. When the tire has circumferential grooves on the equator, it refers to the thickness of the rubber layer measured along a normal to the center of the land portion in the tire width direction that is closest to the tire equatorial plane among the land portions that exist on both sides of the groove in the tire width direction. This corresponds to T1 in Figure 1.

[0050] "Inner liner thickness" and "insulation thickness" refer to the radial thickness of each layer of each component on the equator in the cross section of the tire taken along a plane including the tire rotation axis. If the component does not lie on the equatorial plane, the thickness refers to the radial thickness of each layer of the component at the center of the component in the tire width direction. In Figure 1, T2 corresponds to the insulation thickness, and T3 corresponds to the inner liner thickness.

[0051] "Sidewall thickness" refers to the thickness of the rubber layer forming the sidewall in the direction parallel to the tire width direction at the point where the distance between both sidewalls is the longest on the cross section of the tire taken along a plane including the tire rotation axis. This corresponds to T4 in Figure 1.

[0052] "The thickness of the clinch apex" refers to the thickness of the rubber layer measured along a normal to the main body of the carcass that passes through the point where the sidewall and the clinch apex meet on the outer surface of the tire. In Figure 1, P1 is the point where the sidewall and the clinch apex meet on the outer surface of the tire, L1 is the normal to the main body of the carcass that passes through point P1, and T5 is the thickness of the clinch apex measured along the normal L1.

[0053] For "base tread thickness," "sidewall thickness," "clinch apex thickness," "insulation thickness," and "inner liner thickness," the average values ​​measured on the tire cross section at five points after rotating the tire 72 degrees each are used. Measurements can be performed by creating a cross-sectional piece of the tire at a plane including the tire rotation axis and holding it with the bead spacing aligned to the regular rim width.

[0054] "Recycled carbon black" refers to carbon black obtained from the pyrolysis process of used tires and other products containing carbon black, and refers to carbon black in which, when heated and burned in air by oxidative combustion using a thermogravimetric method in accordance with JIS K 6226-2:2003, the proportion of ash (the mass of the non-burnable component) is 13% by mass or more. In other words, the mass of the weight loss due to oxidative combustion (carbon content) is 87% by mass or less. Recycled carbon black is also called recycled carbon or recycled carbon black, and is sometimes represented by rCB. In this specification, carbon black that is not recycled carbon black is sometimes referred to as regular carbon black to distinguish between the two.

[0055] <Measurement method> "Styrene content" is measured by pyrolysis gas chromatography and NMR measurement ( 1 H-NMR and 13 The amount of components such as "styrene content" is calculated by C-NMR. Unlike physical property values ​​such as complex modulus (E*), the amount of components such as "styrene content" has a true value that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible. In this specification, "pyrolysis gas chromatography" refers to a method in which a sample is heated in a pyrolysis device, the individual components contained in the gas phase components generated by this heating are separated using a separation column, and each isolated component is analyzed.

[0056] "Vinyl content (amount of 1,2-bonded butadiene units)" can be measured by pyrolysis gas chromatography or NMR measurement ( 1 H-NMR and 13 It is calculated using C-NMR. As with the "styrene content," there is a true value for the "vinyl content" that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0057] "Cis content (cis-1,4-bonded butadiene unit amount)" is measured by infrared absorption spectroscopy or NMR measurement ( 1 H-NMR and 13 This is a value measured by C-NMR and is applied to rubber components that have repeating units derived from butadiene, such as BR. As with the "styrene content," the "cis content" also has a true value that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0058] The "total styrene content in the rubber component" refers to the total content (mass%) of styrene moieties in 100% by mass of the rubber component. This is calculated by multiplying the styrene content (mass%) of each rubber component by the mass fraction in the rubber component, and then adding up the resulting values. Specifically, it is calculated as Σ(styrene content (mass%) of each styrene-containing rubber × content (mass%) of each styrene-containing rubber in the rubber component / 100). For example, if the rubber component consists of 30% by mass of a first SBR (styrene content: 25% by mass), 60% by mass of a second SBR (styrene content: 27.5% by mass), and 10% by mass of BR, the total styrene content in 100% by mass of the rubber component is 24.0% by mass (= 25 × 30 / 100 + 27.5 × 60 / 100 + 0 × 10 / 100).

[0059] The "glass transition temperature (Tg) of a rubber composition" is the temperature (tan δ peak temperature) corresponding to the maximum value in the range of -60°C to 40°C in the temperature distribution curve obtained by measuring the tan δ temperature distribution curve using a dynamic viscoelasticity measuring device (e.g., an Iplexer series manufactured by GABO) under conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / min. In the measurement in the range of -60 to 40°C, if the tan δ value continues to gradually increase or decrease with increasing temperature, the glass transition temperature of the rubber composition is taken to be 40°C or -60°C, respectively. In addition, if there are two or more points showing maximum values ​​in the range of -60°C to 40°C, the lowest temperature point is taken to be the glass transition temperature.

[0060] The "weight average molecular weight (Mw)" can be determined by converting the measured value into standard polystyrene equivalents using gel permeation chromatography (GPC) (for example, a GPC-8000 series manufactured by Tosoh Corporation, a differential refractometer as the detector, and a TSKgel SuperMultipore HZ-M column manufactured by Tosoh Corporation). This applies to, for example, SBR, BR, etc.

[0061] The "ash content of recycled carbon black" is measured by the thermogravimetric method of JIS K 6226-2:2003.

[0062] The "average primary particle size" is a value obtained by photographing particles with a transmission or scanning electron microscope and calculating the arithmetic mean of the particle sizes of 400 particles. If the particle shape is spherical, the particle size is the diameter of the sphere, and if the particle shape is non-spherical, the particle size is calculated from the microscope image as the circle-equivalent diameter (positive square root of {4 × (particle area) / π}).

[0063] The "nitrogen adsorption specific surface area (N2SA) of carbon black" is measured in accordance with JIS K 6217-2:2017.

[0064] The "nitrogen adsorption specific surface area (N2SA) of silica" is measured by the BET method in accordance with ASTM D3037-93.

[0065] <Tires> A tire according to an embodiment of the present invention will be described below with reference to the drawings as appropriate. However, the drawings are merely examples for the purpose of explanation.

[0066] FIG. 1 is a schematic diagram showing a portion of a cross section (upper right portion of the cross section) taken along the tire meridian of a tire according to one embodiment of the present invention. In FIG. 1, the tread portion having a contact patch is composed of a cap tread including the contact patch and a base tread 1 radially inward of the cap tread. Also shown are sidewalls 4 disposed on the outer side of the tread portion in the tire width direction, and a clinch apex 5 extending from one end of the sidewall 4 to the rim. Also shown in FIG. 1 are an inner liner 3 constituting the inner surface of the tire, and an insulation 2 radially outward of the inner liner 3. The thickness of the base tread is indicated by T1, the thickness of the insulation by T2, the thickness of the inner liner by T3, the thickness of the sidewall by T4, and the thickness of the clinch apex by T5.

[0067] In an embodiment of the present invention, it is preferred that at least one tire component selected from the group consisting of the base tread, sidewall, clinch apex, insulation, and inner liner contains recycled carbon black. In another embodiment, it is preferred that at least one tire component selected from the group consisting of the base tread, clinch apex, insulation, and inner liner contains recycled carbon black, and it is more preferred that at least one tire component selected from the group consisting of the base tread, insulation, and inner liner contains recycled carbon black. In yet another embodiment, it is preferred that at least one tire component selected from the group consisting of the base tread, sidewall, insulation, and inner liner contains recycled carbon black.

[0068] In one preferred embodiment, the at least one tire component containing recycled carbon black is a base tread. In another preferred embodiment, the at least one tire component containing recycled carbon black is a clinch apex. In another preferred embodiment, the at least one tire component containing recycled carbon black is a sidewall. In yet another preferred embodiment, the at least one tire component containing recycled carbon black is an insulation. In yet another preferred embodiment, the at least one tire component containing recycled carbon black is an innerliner.

[0069] In another preferred embodiment, the tire components containing recycled carbon black are at least two rubbers selected from the group consisting of a base tread, a clinch apex, an insulation rubber, and an inner liner rubber, or at least three rubbers selected from the group, or all of the base tread, the clinch apex rubber, the insulation rubber, and the inner liner rubber.

[0070] In another preferred embodiment, the tire component containing recycled carbon black is at least one component selected from the group consisting of a sidewall, a clinch apex, an insulation, and an inner liner rubber, or at least two or three components selected from the group, or all of the sidewall, the clinch apex rubber, the insulation rubber, and the inner liner rubber.

[0071] A tire according to an embodiment of the present invention has at least one tire component made of a rubber composition containing recycled carbon black, wherein A represents the thickness (mm) of the tire component, B represents the total content (parts by mass) of carbon black contained in the rubber composition, Wt represents the cross-sectional width (mm) of the tire, and Dt represents the outer diameter (mm) of the tire, and A, B, Wt, and Dt simultaneously satisfy the following formulas (1) and (2): (1) (π / 4)×(Dt 2 / Wt)≧1700 (2) (Dt 2 / Wt) / (B×A)>20

[0072] (Regarding formula (1)) As Dt increases, the value of the left side of equation (1) increases, and conversely, as Dt decreases, the value decreases. On the other hand, as Wt increases, the value of the left side of equation (1) decreases, and conversely, as Wt decreases, the value increases. Therefore, by focusing on this point and adjusting Dt and Wt, it is possible to adjust Dt and Wt so that they satisfy equation (1).

[0073] The right side of formula (1) is preferably 1750, more preferably 1800, even more preferably 1850, even more preferably 1880, even more preferably 1900, even more preferably 1950, and even more preferably 2000. On the other hand, there is no particular upper limit to the value of the left side of formula (1), but it is usually about 2800 or may be about 2600.

[0074] The tire outer diameter Dt is preferably 585 mm or more, more preferably 600 mm or more, and even more preferably 625 mm or more. The tire outer diameter Dt is preferably less than 843 mm, more preferably less than 725 mm, and even more preferably less than 685 mm.

[0075] The tire section width Wt is preferably 125 mm or more, more preferably 150 mm or more, and even more preferably 175 mm or more, and is preferably less than 305 mm, more preferably less than 245 mm, and even more preferably less than 210 mm.

[0076] Specific examples of tire sizes that satisfy formula (1) include 145 / 60R18, 145 / 60R19, 155 / 55R18, 155 / 55R19, 155 / 70R17, 155 / 70R19, 165 / 55R20, 165 / 55R21, 165 / 60R19, 165 / 65R19, 165 / 70R18, 175 / 55R19, 175 / 55R20, 175 / 55R22, 175 / 60R18, 185 / 55R19, 185 / 60R20, 195 / 50R20, and 195 / 55R20.

[0077] (Regarding formula (2)) The right side of formula (2) is preferably 23, more preferably 25, even more preferably 30, even more preferably 35, even more preferably 40, and even more preferably 50. On the other hand, there is no particular upper limit to the value of the left side of formula (2), but it is usually about 150, or may be about 120 or about 100.

[0078] On the left side of formula (2), the values ​​of Dt and Wt can be adjusted as described above. Furthermore, B can be adjusted by changing the amount of carbon black contained in the rubber composition, and A can be adjusted by changing the thickness of the tire component. This allows the value of formula (2) to be adjusted.

[0079] (negative rate of tread surface) Figure 3 shows the contact patch shape of a tire according to one embodiment of the present invention when a normal load is applied in a normal state. In this tire, the tread surface includes shoulder land portions 45 located on the outermost sides of the tire and defined by a pair of outermost circumferential main grooves 41 extending in the tire circumferential direction, and a center land portion 43 sandwiched between the shoulder land portions. In Figure 3, two circumferential grooves 42 are provided in the center land portion. In this embodiment, each circumferential groove 42 extends linearly in parallel with the tire circumferential direction, but the circumferential grooves 42 may extend in a wavy pattern, for example.

[0080] In one embodiment, the negative ratio of the center land portion is preferably more than 0% and less than 15%. The negative ratio of the center land portion is more than 0%, preferably more than 2%, more preferably more than 4%, and even more preferably more than 6%. The negative ratio of the center land portion is less than 15%, preferably less than 14%, more preferably less than 13%, and even more preferably less than 12%.

[0081] In one embodiment, the negative ratio of the shoulder land portion is preferably more than 20%. The negative ratio of the shoulder land portion is more preferably more than 23%, even more preferably more than 25%, even more preferably more than 28%, and even more preferably more than 30. On the other hand, there is no particular upper limit as long as the required grip can be maintained, but it is, for example, less than 55%, preferably less than 50%, more preferably less than 45%, and even more preferably less than 40%.

[0082] (A) The value of A is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 1 mm or more, while the value is preferably 10 mm or less, more preferably less than 10 mm, even more preferably 9 mm or less, and even more preferably 8 mm or less.

[0083] The value of A may vary depending on the type of tire component. In the case of a base tread, for example, the thickness of the base tread is preferably 1.0 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm or more. There is no particular upper limit, but it is preferably 5.0 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less.

[0084] In the case of the sidewall, for example, the thickness of the sidewall is preferably 1.0 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm or more. There is no particular upper limit, but it is preferably 5.0 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less.

[0085] In the case of a clinch apex, for example, the thickness of the clinch apex is preferably 4 mm or more, more preferably 4.5 mm or more, and even more preferably 5 mm or more. There is no particular upper limit, but it is preferably 8 mm or less, more preferably 7 mm or less, and even more preferably 6 mm or less.

[0086] In the case of insulation, for example, the thickness of the insulation is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 0.7 mm or more. There is no particular upper limit, but it is preferably 2 mm or less, more preferably 1.5 mm or less, and even more preferably 1.0 mm or less.

[0087] In the case of an inner liner, for example, the thickness of the inner liner is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 1 mm or more. There is no particular upper limit, but it is preferably 2.5 mm or less, more preferably 2 mm or less, and even more preferably 1.5 mm or less.

[0088] <Rubber composition> The rubber composition used in the tire components constituting the tire of this embodiment will be described. In an embodiment of the present invention, in at least one of the components constituting the tire, the rubber composition constituting that component contains recycled carbon black. In a preferred embodiment, the tire component made of a rubber composition containing recycled carbon black can be at least one tire component selected from the base tread, sidewall, clinch apex, insulation, and inner liner. Below, we will explain the case where each rubber composition constituting each component of the base tread, clinch apex, sidewall, insulation, and inner liner contains recycled carbon black. In the following explanation, by replacing recycled carbon black with regular carbon black, a rubber composition for each component not containing recycled carbon black can be obtained.

[0089] [Rubber composition for base tread] Each component of the rubber composition for the base tread will be described.

[0090] <Rubber component> The rubber composition constituting the base tread preferably contains a rubber component containing an isoprene-based rubber (IR rubber) and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber is preferably more than 80% by mass based on 100% by mass of the rubber component. In this case, the rubber component may contain rubber components other than the IR rubber and the BR. Alternatively, the rubber component may consist only of the IR rubber and the BR. Each rubber that can constitute the rubber component is described below.

[0091] (Isoprene rubber) Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. Examples of NR include SIR20, RSS#3, TSR20, and SVR-L, which are commonly used in the tire industry. Examples of IR include IR2200 and other commonly used rubbers. Examples of modified NR include deproteinized natural rubber (DPNR) and highly purified natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. Isoprene-based rubbers may be used alone or in combination.

[0092] The content of the IR rubber in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, more preferably more than 40% by mass, and even more preferably 50% by mass or more. On the other hand, the content is, for example, less than 95% by mass, preferably less than 90% by mass, and more preferably less than 80% by mass. By keeping the content within the above range, not only is abrasion resistance improved, but processability also tends to be improved.

[0093] (BR) The BR is not particularly limited, and examples thereof include those commonly used in the tire industry, such as BR with a high cis content, BR containing 1,2-syndiotactic polybutadiene crystals (SPB-containing BR), butadiene rubber synthesized using a rare earth catalyst (rare earth-based BR), tin-modified butadiene rubber modified with a tin compound (tin-modified BR), and other modified butadiene rubbers (modified BR).Commercially available BRs include those from UBE Corporation, JSR Corporation, Asahi Kasei Corporation, and Zeon Corporation. The modified BR may be any BR having a functional group that interacts with a filler such as silica. Examples include terminal-modified BR (terminal-modified BR having the functional group at the terminal) in which at least one terminal of the BR has been modified with a compound (modifier) ​​having the functional group, main-chain-modified BR having the functional group in the main chain, main-chain terminal-modified BR having the functional group in the main chain and at least one terminal (for example, main-chain terminal-modified BR having the functional group in the main chain and at least one terminal modified with the modifier), and terminal-modified BR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or epoxy group introduced therein. Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imido group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, and an epoxy group. These functional groups may have a substituent. Among these, an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0094] The cis content of BR is preferably more than 90 mol%, more preferably more than 93 mol%, even more preferably more than 95 mol%, and even more preferably 97 mol% or more. The cis content of BR is measured by the above-mentioned measurement method.

[0095] As the BR, for example, products from UBE Corporation, JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., etc. may be used. One type of BR may be used alone, or two or more types may be used in combination.

[0096] The BR content in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 15% by mass, more preferably more than 20% by mass, and even more preferably 25% by mass or more. On the other hand, the content is, for example, less than 90% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and even more preferably less than 60% by mass. By keeping the content within the above range, abrasion resistance tends to be improved in addition to the effects of the present invention.

[0097] The total content of the IR rubber and BR in 100% by mass of the rubber component is preferably more than 80% by mass, more preferably more than 90% by mass, and even more preferably more than 95% by mass, and may be 100% by mass.

[0098] (SBR) Styrene-butadiene rubber (SBR) is not particularly limited and includes, for example, unmodified emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR), as well as modified SBRs such as modified emulsion-polymerized styrene-butadiene rubber (modified E-SBR) and modified solution-polymerized styrene-butadiene rubber (modified S-SBR). Modified SBRs include SBRs whose terminals and / or main chains are modified, and modified SBRs (condensates, branched structures, etc.) coupled with tin or silicon compounds. SBRs include oil-extended types in which flexibility is adjusted by adding an extender oil, and non-oil-extended types in which no extender oil is added, and either type can be used. Examples of such SBRs include those manufactured by JSR Corporation, Asahi Kasei Chemicals Corporation, Nippon Zeon Corporation, and ZS Elastomers Co., Ltd. SBRs can be used alone or in combination of two or more types.

[0099] The styrene content of SBR is preferably more than 15% by mass, more preferably more than 20% by mass, and even more preferably more than 23% by mass. From the viewpoint of fuel economy, the styrene content is preferably less than 40% by mass, more preferably less than 35% by mass, and even more preferably less than 30% by mass. The styrene content of SBR is measured by the above-mentioned measurement method.

[0100] The vinyl content (amount of 1,2-bonded butadiene units) of SBR is preferably more than 10 mol%, more preferably more than 15 mol%, and more preferably more than 20 mol%. It is also preferably less than 80 mol%, preferably less than 50 mol%, and more preferably less than 30 mol%. The vinyl content of SBR is measured by the above-mentioned measurement method.

[0101] From the viewpoint of fuel economy, the glass transition point (Tg) of SBR is preferably higher than −85° C., more preferably higher than −80° C., and even more preferably higher than −75° C., and is preferably lower than −30° C., more preferably lower than −35° C., and even more preferably lower than −40° C. The Tg of SBR is measured by the above-mentioned measurement method.

[0102] The weight average molecular weight (Mw) of SBR is preferably 100,000 or more, more preferably 150,000 or more, and even more preferably 190,000 or more, from the viewpoint of fuel economy. Furthermore, from the viewpoint of crosslink uniformity, etc., Mw is preferably 2.5 million or less, more preferably 2 million or less, and even more preferably 1 million or less. Mw of SBR is measured by the above-mentioned measurement method.

[0103] When the rubber component contains SBR, the content of SBR in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, more preferably more than 30% by mass, and even more preferably 40% by mass or more. On the other hand, the content is, for example, 100% by mass or less, preferably less than 90% by mass, and more preferably less than 80% by mass. By keeping the content within the above range, there is a tendency for excellent grip performance and abrasion resistance to be achieved.

[0104] (Other rubber) The other rubbers that can be used other than those mentioned above are not particularly limited, and rubbers used in the tire field can be used. Examples include diene rubbers such as acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), and styrene-isoprene-butadiene copolymer rubber (SIBR). The other rubbers may be used alone or in combination of two or more.

[0105] (Rubber components synthesized from recycled and biomass-derived raw materials) Monomers, which are structural units of synthetic rubbers such as IR, SBR, and BR, may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene. Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. Among these, recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are preferably used as raw materials.

[0106] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0107] Furthermore, the monomers that are the structural units of polymers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to materials derived from natural resources such as plants. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0108] Monomers derived from biomass (biomass monomers) are not particularly limited, and examples thereof include biomass-derived butadiene and biomass-derived aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. The method for producing biomass monomers is not particularly limited, and examples include biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0109] Polymers synthesized from biomass monomer components (biomass polymers) are not particularly limited and include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compounds, etc. Examples of the aromatic vinyl / butadiene copolymers include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0110] Whether a polymer's raw material is biomass-derived can be determined by its pMC (percent modern carbon) measured in accordance with ASTM D6866-10. pMC is the modern standard reference carbon. 14 of sample against C concentration 14This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0111] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14 C exists. 14 The half-life of C is 5730 years, 14 C is decreasing regularly. Therefore, in the case of fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when they were first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C elements.

[0112] on the other hand, 14 C is constantly produced by cosmic rays undergoing nuclear reactions in the atmosphere. 14 The amount of C is balanced between radioactive decay and nuclear reaction, and in the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio in a compound can be calculated by using the difference between these values.

[0113] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12C) is measured. 14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14 The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0114] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, it will usually not reach 100 under normal conditions, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC), which corresponds to the above-mentioned biomass ratio of 0%.

[0115] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0116] <Filler> The filler refers to a reinforcing filler, and in this embodiment, the rubber composition constituting at least one of the predetermined tire components contains recycled carbon black (rCB). In this embodiment, the filler includes not only rCB but also regular carbon black and other reinforcing fillers used in the tire industry. When the filler contains silica, it may further contain a silane coupling agent.

[0117] (recycled carbon black) In an embodiment of the present invention, recycled carbon black refers to carbon black obtained from the pyrolysis process of used tires or other products containing carbon black, and which has a mass ratio of ash (ash content), which is an incombustible component, of 13% by mass or more when subjected to oxidative combustion by heating in air, as measured by thermogravimetry in accordance with JIS K 6226-2: 2003. The ash content of recycled carbon black is preferably 14% by mass or more, more preferably 15% by mass or more, even more preferably 16% by mass or more, and even more preferably 17% by mass or more.

[0118] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975, citing "Rubber Chemistry and Technology," Vol. 85, No. 3, pp. 408-449 (2012), particularly pp. 438, 440, and 442, describes the carbon black as being obtained by 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 typically lacks functional groups on its surface, as mentioned in

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

[0119] Recycled carbon black may lack functional groups on its surface, or 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. 3,173,251, 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. Furthermore, in Japanese Patent Publication No. 6,856,781, carbon black obtained from a pyrolysis process is treated with an amino acid compound containing at least one thiol or disulfide group to obtain surface-activated carbon black. The recycled carbon black of this embodiment also includes carbon blacks treated to include functional groups on their surfaces.

[0120] As the recycled carbon black, commercially available products from Strable Green Carbon, LD Carbon, etc. can be used.

[0121] The average primary particle diameter of recycled carbon black is preferably 20 nm or more, more preferably 25 nm or more, even more preferably 30 nm or more, and particularly preferably 35 nm or more. By setting the average primary particle diameter of carbon black within the above range, it is thought that the rubber molecules bound by the carbon black are minimized, allowing them to move flexibly, thereby enabling the polymer molecular chain to relieve stress in response to input force. On the other hand, the average primary particle diameter is preferably 90 nm or less, more preferably 75 nm or less, and even more preferably 60 nm or less. The average primary particle diameter of carbon black is measured by the above-mentioned measurement method.

[0122] The nitrogen adsorption specific surface area (N2SA) of the recycled carbon black is not particularly limited, but from the viewpoint of obtaining sufficient reinforcement and good abrasion resistance, it is preferred that the N2SA be 30 m 2 / g or more is preferable, and 40m 2 / g is more preferable, and 50m 2 / g or more is more preferable, and 60m 2 / g or more is more preferable, and 70m 2 In addition, from the viewpoint of excellent dispersibility and low heat generation, the N2SA has a viscosity of 300 m / g or more. 2 / g is preferable, and 200m 2 / g is more preferable, and 150m 2 / g is more preferable, and 120m 2 / g is more preferable, and 110m 2 / g is more preferable, and 100m 2 / g is more preferable, and 90m 2 / g or less is more preferable. Note that the N2SA of the recycled carbon black in this specification is a value measured in accordance with JIS K 6217-2:2017.

[0123] When recycled carbon black is contained, the content of recycled carbon black is, for example, more than 1 part by mass, preferably more than 3 parts by mass, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the content is preferably less than 70 parts by mass, more preferably less than 65 parts by mass, and even more preferably 60 parts by mass or less. When the content of recycled carbon black is within the above range, sufficient reinforcing properties and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0124] (Carbon black other than rCB) Carbon black other than recycled carbon black (ordinary carbon black) is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N660, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by pyrolysis of methane, such as in a thermal black process. Commercially available carbon blacks 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., and Columbia Carbon Co., Ltd. These may be used alone or in combination.

[0125] The average primary particle diameter of carbon black is preferably 20 nm or more, more preferably 25 nm or more, even more preferably 30 nm or more, and particularly preferably 35 nm or more. By setting the average primary particle diameter of carbon black within the above range, it is thought that the rubber molecules bound by the carbon black are minimized, allowing them to move flexibly, thereby enabling the polymer molecular chain to relieve stress in response to input. Meanwhile, the average primary particle diameter is preferably 90 nm or less, more preferably 75 nm or less, and even more preferably 60 nm or less. The average primary particle diameter of carbon black is measured by the above-mentioned measurement method.

[0126] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, but from the viewpoint of obtaining sufficient reinforcement and good abrasion resistance, it is preferred that the N2SA be 30 m 2 / g or more is preferable, and 40m 2 / g is more preferable, and 50m 2 / g or more is more preferable, and 60m 2 / g or more is more preferable, and 70m 2 In addition, from the viewpoint of excellent dispersibility and low heat generation, the N2SA has a viscosity of 300 m / g or more. 2 / g is preferable, and 200m 2 / g is more preferable, and 150m 2 / g is more preferable, and 120m 2 / g is more preferable, and 110m 2 / g is more preferable, and 100m 2 / g is more preferable, and 90m 2 / g or less is more preferable. In this specification, the N2SA of carbon black is a value measured in accordance with JIS K 6217-2:2017.

[0127] The total content of recycled carbon black and other carbon black is, for example, more than 10 parts by mass, preferably more than 15 parts by mass, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the total content is preferably less than 100 parts by mass, more preferably less than 95 parts by mass, and even more preferably less than 90 parts by mass. When the carbon black content is within the above range, sufficient reinforcing properties and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0128] The ratio (%) of the content of recycled carbon black to the total content of recycled carbon black and other carbon black, i.e., (content of recycled carbon black) / (content of recycled carbon black+content of other carbon black)×100, may be, for example, 50 or less, preferably 20 or less, preferably less than 15, more preferably less than 10, and even more preferably less than 5.

[0129] In addition, when the carbon black to be blended contains recycled carbon black and other carbon black, the content of the other carbon black is automatically determined once the total content of both and the content of the recycled carbon black are determined.

[0130] (silica) The silica is not particularly limited, and can be, for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrated silica), or other silica commonly used in the tire industry. The raw material for silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from a silica-containing product. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. Silica can be used alone or in combination of two or more types.

[0131] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0132] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0133] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, the crystallization of silica in rice husk ash can be suppressed (see, for example, JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222). Amorphous silica extracted from rice husks can be commercially available from Wilmar, Inc.

[0134] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m 2 / g, more preferably 100m 2 / g, more preferably 150m2 / g, particularly preferably 170m 2 The upper limit of the N2SA of silica is not particularly limited, but is preferably 350 m 2 / g, more preferably less than 250m 2 / g, more preferably less than 200m 2 / g. By keeping it within the above range, cut resistance tends to be improved. The N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0135] (Silica content) When silica is contained, the content per 100 parts by mass of the rubber component is not particularly limited, but from the viewpoint of ensuring low fuel consumption performance, it is preferably more than 1 part by mass, more preferably more than 3 parts by mass, and more preferably more than 5 parts by mass. Furthermore, from the viewpoint of silica dispersibility and processability, 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, and even more preferably less than 10 parts by mass. Furthermore, in one embodiment of the present invention, the rubber composition may be substantially free of silica. Furthermore, in this specification, "substantially free of silica" means that the content of silica per 100 parts by mass of the rubber component is preferably 0.1 part by mass or less, more preferably 0.01 part by mass or less, and even more preferably 0 part by mass.

[0136] (Silane coupling agent) When silica is used as filler, it is preferable to further comprise silane coupling agent.Silane coupling agent is not particularly limited, but for example, sulfide-based silane coupling agent such as bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide; mercapto-based silane coupling agent such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; vinyl-based silane coupling agent such as vinyltriethoxysilane, vinyltrimethoxysilane; 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane Examples of suitable silane coupling agents include amino-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. Among these, sulfide-based silane coupling agents and / or mercapto-based silane coupling agents are preferred. Examples of suitable silane coupling agents include those commercially available from Evonik Industries, Momentive, and the like. These silane coupling agents may be used alone or in combination.

[0137] (Silane coupling agent content) When a silane coupling agent is contained, the content of the silane coupling agent is preferably more than 1 part by mass, more preferably more than 3 parts by mass, even more preferably more than 5 parts by mass, and even more preferably more than 7 parts by mass per 100 parts by mass of silica. On the other hand, the content is preferably less than 20 parts by mass, more preferably less than 18 parts by mass, even more preferably less than 16 parts by mass, and even more preferably less than 14 parts by mass. Setting the content within the above ranges tends to improve the dispersibility of silica. Furthermore, when the rubber composition is substantially free of silica, the silane coupling agent is also substantially free of the rubber composition. Here, "substantially free of a silane coupling agent" means that the content of the silane coupling agent is preferably 0.1 parts by mass or less, more preferably 0.01 parts by mass or less, and even more preferably 0 parts by mass per 100 parts by mass of the rubber component.

[0138] (Other fillers) The other fillers are not particularly limited, and materials known in the field of the tire industry can be used, including, for example, inorganic fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, mica, etc. These may be used alone or in combination of two or more.

[0139] <Other compounding agents> In addition to the rubber component and filler, the rubber composition may contain, as appropriate, compounding agents that are generally used in the tire industry, such as plasticizers, processing aids, vulcanized rubber particles, wax, stearic acid, zinc oxide, antioxidants, vulcanizing agents, and vulcanization accelerators.

[0140] (plasticizer) A plasticizer is a material that imparts plasticity to rubber components and encompasses both liquid and solid plasticizers at 25°C. Examples of plasticizers include resins, oils, liquid rubbers, and ester-based plasticizers. These plasticizers may be derived from mineral resources such as petroleum and natural gas, biomass-derived materials, or naphtha recycled from rubber and non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. Plasticizers may be used singly or in combination.

[0141] <Resin> The rubber composition according to the present embodiment may contain a combination of resin components. Resin components that can be used in the present embodiment are not particularly limited, but include resins commonly used in the tire industry, such as adhesive resins such as C9 resins, C5 resins, C5C9 resins, aromatic vinyl resins, dicyclopentadiene resins, terpene resins, rosin resins, and phenol resins. These resin components may be used alone or in combination of two or more.

[0142] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be a copolymer obtained by polymerizing a C9 fraction alone or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. These resins may also be hydrogenated or modified. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene.

[0143] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction, and may be a hydrogenated or modified C5 resin. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions having 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene.

[0144] The term "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be a hydrogenated or modified resin. Examples of C5C9 petroleum resins that can be used include those commercially available from Tosoh Corporation, Luhua, and the like.

[0145] Dicyclopentadiene Resin "Dicyclopentadiene resin" refers to a resin containing dicyclopentadiene (DCPD) as the monomer component with the largest content, and may be a hydrogenated or modified resin. Examples of dicyclopentadiene resins include DCPD / C9 resins obtained by copolymerizing dicyclopentadiene with the C9 fraction, with DCPD / C9 resins being preferred. Examples of DCPD resins that can be used include those commercially available from ExxonMobil Corporation, ENEOS Corporation, Nippon Zeon Co., Ltd., Maruzen Petrochemical Co., Ltd., and the like.

[0146] aromatic vinyl resin The term "aromatic vinyl resin" refers to a resin containing an aromatic vinyl compound such as styrene, α-methylstyrene, vinyltoluene, or p-chlorostyrene as the monomer component with the highest content, and may be a hydrogenated or modified version of such a compound. As the aromatic vinyl resin, a homopolymer of α-methylstyrene or styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, because they are economical, easy to process, and have excellent heat generation properties. As the aromatic vinyl resin, commercially available products from Kraton, Eastman Chemical, Mitsui Chemicals, Inc., etc., can be used.

[0147] Coumarone Resin Coumarone resins refer to resins containing coumarone as a monomer component, and may be hydrogenated or modified. Examples of coumarone resins include coumarone-indene resins, which contain coumarone and indene as monomer components, and coumarone-indene-styrene resins, which contain coumarone, indene, and styrene as monomer components.

[0148] Indene Resin Indene resins are resins containing indene as a monomer component, and may be hydrogenated or modified. Examples of coumarone resins include coumarone-indene resins, which contain coumarone and indene as monomer components, and coumarone-indene-styrene resins, which contain coumarone, indene, and styrene as monomer components.

[0149] Terpene Resin Terpene resins refer to resins containing terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as the most abundant monomer component, and may be hydrogenated or modified. Specific examples of terpene resins include polyterpene resins containing only one or more of the terpene compounds as monomer components; aromatic-modified terpene resins containing the terpene compound and an aromatic compound as monomer components; and terpene phenolic resins containing the terpene compound and a phenolic compound as monomer components. Examples of aromatic compounds that serve as monomer components for aromatic-modified terpene resins include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include phenol, bisphenol A, cresol, and xylenol.

[0150] Rosin-based resin The rosin-based resin refers to a resin containing a rosin acid compound such as abietic acid, neoabietic acid, palustric acid, or isopimaric acid, and may be a hydrogenated or modified version of such a resin. The rosin-based resin is not particularly limited, but examples thereof include natural rosin resin and rosin-modified resins obtained by modifying rosin by hydrogenation, disproportionation, dimerization, esterification, or the like.

[0151] phenolic resin The phenolic resin refers to a resin that contains a phenolic compound such as phenol or cresol as the monomer component with the largest content. The phenolic resin is not particularly limited, but examples thereof include phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, oil-modified phenol formaldehyde resin, and terpene phenol resin.

[0152] When a resin is contained, the content per 100 parts by mass of the rubber component is preferably more than 1 part by mass, more preferably more than 1.5 parts by mass, even more preferably 2 parts by mass or more, and still more preferably 3 parts by mass or more, while the content is preferably less than 40 parts by mass, more preferably less than 20 parts by mass, and even more preferably less than 10 parts by mass.

[0153] (Plasticizers other than resins) Plasticizers other than resins, such as oil, liquid rubber, and ester-based plasticizers, will now be explained.

[0154] <Oil> Examples of oils include mineral oil, vegetable oil, and animal oil. From the viewpoint of life cycle assessment, waste oils used in rubber mixers and engines, and refined waste cooking oils used in restaurants may also be used. One type of oil may be used alone, or two or more types may be used in combination.

[0155] As used herein, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil. Specific examples of mineral oil include mild extracted solvate (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, oils with a low content of polycyclic aromatic compounds (PCA) can also be used as an environmentally friendly measure. Examples of low PCA oils include MES, TDAE, and heavy naphthenic oil. Mineral oils may be used singly or in combination.

[0156] As used herein, examples of vegetable oils include 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 Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above oils, interesterified oils obtained by interesterifying the above oils, hardened oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, and waste edible oils recovered from edible oils and the like. Vegetable oils may be liquid or solid at 25°C. One vegetable oil may be used alone, or two or more may be used in combination.

[0157] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is esterified with a fatty acid. 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 (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. The acylglycerol may be liquid or solid at 25°C.

[0158] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, the 1 When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0159] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. 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.

[0160] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., saturated fatty acid or monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing saturated fatty acid or monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0161] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0162] Examples of animal oils include fish oil, beef tallow, whale oil, and oleyl alcohol derived from these.

[0163] The oil content per 100 parts by mass of the rubber component is preferably more than 1 part by mass, more preferably more than 2 parts by mass, and even more preferably 3 parts by mass or more. The content is preferably less than 20 parts by mass, more preferably less than 15 parts by mass, and even more preferably 10 parts by mass or less. The oil content includes the amount of oil contained in the rubber component as an extender oil and the amount of oil contained in other components such as sulfur.

[0164] <Liquid rubber> The liquid rubber is not particularly limited as long as it is a polymer that is in a liquid state at 25° C., and examples thereof include liquid butadiene rubber (liquid BR), liquid styrene butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene isoprene rubber (liquid SIR), liquid farnesene rubber, etc. One type of liquid rubber may be used alone, or two or more types may be used in combination.

[0165] <Ester-based plasticizers> Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di-2-ethylhexyl azelate (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). One type of ester-based plasticizer may be used alone, or two or more types may be used in combination.

[0166] (vulcanized rubber particles) The 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 standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. One type of vulcanized rubber particle may be used alone, or two or more types may be used in combination.

[0167] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0168] As commercially available vulcanized rubber, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., etc. can be used.

[0169] (processing aids) Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. One type of processing aid may be used alone, or two or more types may be used in combination. Examples of processing aids that can be used include those commercially available from Schill + Seilacher, Performance Additives, etc.

[0170] When a processing aid is contained, the content thereof per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of improving processability, and 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 from the viewpoint of abrasion resistance and breaking strength.

[0171] (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. Waxes commercially available from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., etc. can be used. One type of wax may be used alone, or two or more types may be used in combination.

[0172] When wax is contained, the content per 100 parts by mass of the 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, and 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 from the viewpoint of preventing whitening of the tire due to bloom.

[0173] (stearic acid) When stearic acid is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 0.7 parts by mass, and even more preferably 1.0 part by mass or more from the viewpoint of processability, while the content is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, and even more preferably less than 3 parts by mass from the viewpoint of vulcanization rate.

[0174] (zinc oxide) When zinc oxide is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 0.7 parts by mass, and even more preferably more than 1 part by mass from the viewpoint of processability, while the content is preferably 10 parts by mass or less, more preferably less than 7 parts by mass, and even more preferably 5 parts by mass or less from the viewpoint of abrasion resistance.

[0175] (anti-aging agent) The antioxidant is not particularly limited, but examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), and N,N'-ditolyl-p-phenylenediamine. p-phenylenediamine-based antioxidants such as diphenyl ether diphenyl ether (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; 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 that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., and Flexis Co., Ltd. One type of antioxidant may be used alone, or two or more types may be used in combination.

[0176] When an antioxidant is contained, the content thereof per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 0.8 parts by mass, and even more preferably more than 1.0 part by mass, while the content is preferably less than 7.0 parts by mass, more preferably less than 5.0 parts by mass, and even more preferably 3.0 parts by mass or less.

[0177] (vulcanizing agent) As the vulcanizing agent, sulfur is preferably used. The vulcanizing agents may be used alone or in combination of two or more.

[0178] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur (oil-treated sulfur, special sulfur treated with a dispersant, masterbatch-type sulfur, etc.), and insoluble sulfur (oil-treated insoluble sulfur, etc.), all of which are preferably used. Among these, powdered sulfur is preferred. Examples of sulfur that can be used include those manufactured and sold by Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanritsu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc.

[0179] Known organic crosslinking agents can also be used as vulcanizing agents other than sulfur. The organic crosslinking agent is not particularly limited as long as it can form crosslinked chains other than polysulfide bonds. Examples of the organic crosslinking agent include alkylphenol-sulfur chloride condensate, sodium 1,6-hexamethylene-dithiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and dicumyl peroxide. 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane is preferred. These organic crosslinking agents can be commercially available from Taoka Chemical Co., Ltd., Lanxess K.K., Flexis, and other companies.

[0180] When a vulcanizing agent is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.4 parts by mass, more preferably more than 0.5 parts by mass, even more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass. On the other hand, the content is preferably less than 6.0 parts by mass, more preferably 5.0 parts by mass or less, and even more preferably less than 4.0 parts by mass. When the content of the vulcanizing agent is within the above range, an appropriate reinforcing effect tends to be obtained, and the effects of the present invention tend to be more effectively exhibited. Note that when the vulcanizing agent contains components other than sulfur, such as oil-treated sulfur, the content of the vulcanizing agent refers to the content of the sulfur component itself.

[0181] (Vulcanization accelerator) The vulcanization accelerator is not particularly limited, but examples thereof include sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, guanidine vulcanization accelerators, thiuram vulcanization accelerators, thiourea vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehyde-amine vulcanization accelerators, aldehyde-ammonia vulcanization accelerators, imidazoline vulcanization accelerators, xanthate vulcanization accelerators, and caprolactam disulfide. These vulcanization accelerators may be used alone or in combination of two or more. Among them, one or more vulcanization accelerators selected from the group consisting of sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, and guanidine vulcanization accelerators are preferred, as they more suitably achieve the desired effects. The vulcanization accelerators may be used alone or in combination of two or more.

[0182] Examples of sulfenamide vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS).

[0183] Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole (MBT) or a salt thereof, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinothio)benzothiazole.

[0184] Examples of guanidine vulcanization accelerators include 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatechol borate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, and 1,3-di-o-cumenyl-2-propionylguanidine.

[0185] Examples of thiuram vulcanization accelerators include tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide (TMTM), dipentamethylene thiuram disulfide, and dipentamethylene thiuram tetrasulfide.

[0186] Examples of the thiourea vulcanization accelerator include thiourea compounds such as thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea and diorthotolylthiourea, N,N'-diphenylthiourea, trimethylthiourea and N,N'-diethylthiourea.

[0187] Examples of dithiocarbamate vulcanization accelerators include piperidinium pentamethylenedithiocarbamate (PPDC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), zinc dibutyldithiocarbamate (ZnBDC), zinc dibenzyldithiocarbamate (ZDBzC), zinc N-ethyl-N-phenyldithiocarbamate (ZnEPDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), sodium dibutyldithiocarbamate (NaBDC), copper dimethyldithiocarbamate (CuMDC), iron dimethyldithiocarbamate (FeMDC), and tellurium diethyldithiocarbamate (TeEDC).

[0188] The content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably more than 0.3 parts by mass, more preferably more than 0.4 parts by mass, and even more preferably more than 0.5 parts by mass. On the other hand, the content is preferably less than 4.0 parts by mass, more preferably less than 3.0 parts by mass, and even more preferably less than 2.0 parts by mass. When the content of the vulcanization accelerator is within the above range, breaking strength and elongation tend to be ensured, and the effects of the present invention tend to be more favorably exhibited.

[0189] [Sidewall rubber composition] Each component of the rubber composition for a sidewall will be described.

[0190] <Rubber component> The rubber component is described below, and is also as described for the rubber composition for the base tread. The rubber composition constituting the sidewall contains a rubber component including an IR rubber and a butadiene rubber, and the total content of the IR rubber and the butadiene rubber (BR) is preferably more than 80% by mass of 100% by mass of the rubber component. In this case, the rubber component may contain rubber components other than the IR rubber and the BR. The rubber component may also consist solely of rubber selected from the IR rubber and the BR. Examples of rubber components other than the IR rubber and the BR include diene rubbers such as styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). The description of the rubber composition for the base tread is similarly applicable to these other rubber components. These other rubber components may be used alone or in combination of two or more.

[0191] (Content) The content of the rubber component is as described in the section on the rubber composition for the base tread, and the content of the IR rubber in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, more preferably more than 40% by mass, and even more preferably 50% by mass or more. On the other hand, the content is, for example, 100% by mass or less, preferably less than 90% by mass, and more preferably less than 80% by mass. By keeping the content within the above range, abrasion resistance and processability tend to be improved.

[0192] The BR content in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, and more preferably more than 30% by mass. On the other hand, the content is, for example, less than 90% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and even more preferably less than 60% by mass. By keeping the content within the above range, abrasion resistance tends to be improved.

[0193] The total content of the IR rubber and BR in 100% by mass of the rubber component is preferably more than 80% by mass, more preferably more than 90% by mass, and even more preferably more than 95% by mass, and may be 100% by mass.

[0194] When the rubber component contains SBR, the content of SBR in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, and more preferably more than 30% by mass. On the other hand, the content is, for example, less than 90% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and even more preferably less than 60% by mass. By keeping the content within the above range, grip performance and abrasion resistance tend to be improved.

[0195] <Filler> The filler may include recycled carbon black (rCB), carbon black other than rCB, and silica. When the filler includes silica, it may further include a silane coupling agent. The filler may further include other fillers other than carbon black and silica. The components that may constitute the filler are described below, and are also as described in the section on the rubber composition for the base tread.

[0196] (Carbon black content) The amount of recycled carbon black is, for example, more than 2 parts by mass, preferably more than 3 parts by mass, more preferably more than 5 parts by mass, and even more preferably 7 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the amount is preferably less than 60 parts by mass, more preferably less than 55 parts by mass, and even more preferably less than 50 parts by mass. The total amount of recycled carbon black and other carbon black is, for example, more than 20 parts by mass, preferably more than 25 parts by mass, and more preferably 30 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the total amount is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass. When the carbon black content is within the above range, sufficient reinforcement and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0197] (Silica content) When silica is contained, the explanation given for the base tread rubber is similarly applicable to the silica content.

[0198] (Silane coupling agent content) When a silane coupling agent is contained, the content of the silane coupling agent can be similarly applied to the explanation given for the rubber composition for the base tread.

[0199] (Other compounding agents) For other details than those mentioned above, the explanation given for the rubber composition for the base tread is similarly applicable.

[0200] [Rubber composition for clinch apex] Each component of the rubber composition for the clinch apex will be described.

[0201] <Rubber component> The rubber component is described below, and is also as described for the rubber composition for the base tread. The rubber composition constituting the clinch apex includes a rubber component containing an IR rubber and a butadiene rubber, and the total content of the IR rubber and the butadiene rubber is preferably more than 80 mass% of 100 mass% of the rubber component. In this case, the rubber component may include a rubber component other than the IR rubber and the BR. The rubber component may also consist solely of a rubber selected from the IR rubber and the BR. Examples of rubber components other than the IR rubber and the BR include diene rubbers such as styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). The same explanation as given for the rubber composition for the base tread applies to these other rubber components. These other rubber components may be used alone or in combination of two or more.

[0202] (Content) The content of the IR rubber in 100% by mass of the rubber component is, for example, more than 30% by mass, preferably more than 40% by mass, more preferably more than 45% by mass, and even more preferably 50% by mass or more, while the content is, for example, 100% by mass or less, preferably less than 95% by mass, and more preferably less than 90% by mass.

[0203] The BR content in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 20% by mass, more preferably more than 30% by mass, and even more preferably more than 40% by mass, while the BR content is, for example, less than 90% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and even more preferably less than 60% by mass.

[0204] The total content of the IR rubber and BR in 100% by mass of the rubber component is preferably more than 80% by mass, more preferably more than 90% by mass, and even more preferably more than 95% by mass, and may be 100% by mass.

[0205] <Filler> The filler may include recycled carbon black (rCB), carbon black other than rCB, and silica. When the filler includes silica, it may further include a silane coupling agent. The filler may further include other fillers other than carbon black and silica. The components that may constitute the filler are as described in the section on the rubber composition for the base tread.

[0206] (Carbon black content) The amount of recycled carbon black is, for example, more than 2 parts by mass, preferably more than 3 parts by mass, more preferably more than 5 parts by mass, and even more preferably 7 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the amount is preferably less than 60 parts by mass, more preferably less than 55 parts by mass, and even more preferably less than 50 parts by mass. The total amount of recycled carbon black and other carbon black is, for example, more than 20 parts by mass, preferably more than 25 parts by mass, and more preferably 30 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the total amount is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass. When the carbon black content is within the above range, sufficient reinforcement and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0207] (Silica content) When silica is contained, the explanation given for the base tread rubber is similarly applicable to the silica content.

[0208] (Silane coupling agent content) When a silane coupling agent is contained, the content of the silane coupling agent can be similarly applied to the explanation given for the rubber composition for the base tread.

[0209] (Other compounding agents) The rubber composition preferably contains a resin. Regarding other details, the explanation given for the rubber composition for the base tread is similarly applicable.

[0210] [Rubber composition for insulation] Each component of the rubber composition for insulation will be described below.

[0211] <Rubber component> The rubber component is described below, and is also as described for the rubber composition for the base tread. The rubber composition constituting the insulation includes a rubber component containing an IR rubber and a styrene-butadiene rubber (SBR), and the total content of the IR rubber and the SBR is preferably more than 80% by mass of 100% by mass of the rubber component. In this case, the rubber component may contain rubber components other than the IR rubber and the SBR. The rubber component may also consist solely of a rubber selected from the IR rubber and the SBR. Examples of rubber components other than the IR rubber and the SBR include diene rubbers such as butadiene rubber (BR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). The description of the rubber composition for the base tread is similarly applicable to these other rubber components. These other rubber components may be used alone or in combination of two or more.

[0212] (Content) The content of the IR rubber in 100% by mass of the rubber component is, for example, more than 20% by mass, preferably more than 25% by mass, more preferably more than 30% by mass, and even more preferably 35% by mass or more, while the content is, for example, 100% by mass or less, preferably less than 95% by mass, and more preferably less than 90% by mass.

[0213] The amount of SBR in 100% by mass of the rubber component is, for example, more than 10% by mass, preferably more than 15% by mass, and more preferably 20% by mass or more, while the amount is, for example, less than 90% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and even more preferably less than 60% by mass.

[0214] The total content of the IR rubber and SBR in 100% by mass of the rubber component is preferably more than 80% by mass, more preferably more than 90% by mass, and even more preferably more than 95% by mass, and may be 100% by mass. By keeping the content within the above range, processability and abrasion resistance tend to be improved.

[0215] <Filler> The filler may include recycled carbon black (rCB), carbon black other than rCB, and silica. When the filler includes silica, it may further include a silane coupling agent. The filler may further include other fillers other than carbon black and silica. The components that may constitute the filler are as described in the section on the rubber composition for the base tread.

[0216] (Carbon black content) The amount of recycled carbon black is, for example, more than 2 parts by mass, preferably more than 3 parts by mass, more preferably more than 5 parts by mass, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. Meanwhile, the amount is preferably less than 90 parts by mass, more preferably less than 80 parts by mass, and even more preferably less than 70 parts by mass. The total amount of recycled carbon black and other carbon black is, for example, more than 20 parts by mass, preferably more than 25 parts by mass, and more preferably 30 parts by mass or more, per 100 parts by mass of the rubber component. Meanwhile, the total amount is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass. When the carbon black content is within the above range, sufficient reinforcement and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0217] In addition, for carbon black (including recycled carbon black), the explanation given for the rubber composition for the clinch apex can be similarly applied.

[0218] (Silica content) When silica is contained, the explanation given for the rubber composition for the clinch apex can be applied to the content of silica.

[0219] (Silane coupling agent content) When a silane coupling agent is contained, the content of the silane coupling agent can be similarly applied to the explanation given for the rubber composition for the clinch apex.

[0220] (Other compounding agents) The rubber composition preferably contains a resin. Regarding the other details, the explanation given for the rubber composition for the clinch apex is similarly applicable.

[0221] [Rubber composition for inner liner] Each component of the rubber composition for an inner liner will be described.

[0222] <Rubber component> The rubber component is described below and is also as described for the rubber composition for a clinch apex. The rubber composition for an inner liner includes a rubber component containing a butyl-based rubber, and the content of the butyl-based rubber is preferably more than 90% by mass relative to 100% by mass of the rubber component. In this case, the rubber composition may include a rubber component other than the butyl-based rubber. In this case, it is preferable that the rubber component contains an isoprene-based rubber. The rubber component may consist solely of a butyl-based rubber.

[0223] (butyl rubber) The butyl rubber is preferably a polymer containing an isobutylene unit and an isoprene unit as a repeating unit, and a derivative thereof. Examples of such a butyl rubber include butyl rubber (IIR); halogenated butyl rubbers such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR). Among these, halogenated butyl rubber is preferred, and brominated butyl rubber and chlorinated butyl rubber are more preferred, from the viewpoint of achieving a balanced improvement in sheet processability and air barrier properties. These may be used alone or in combination.

[0224] As for butyl rubber, in addition to regular butyl rubber (butyl rubber other than recycled butyl rubber), recycled butyl rubber can be used in combination. Recycled butyl rubber usually has a high content of non-halogenated butyl rubber (regular butyl rubber), so by using it in combination with halogenated butyl rubber, good air barrier properties and vulcanization speed can be ensured. Recycled butyl rubber can be used alone or in combination of two or more types.

[0225] The rubber component may contain other rubber components in addition to the butyl rubber. Examples include diene rubbers such as isoprene rubber (IR rubber), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). The same explanation as given for the rubber composition for the base tread applies to these other rubber components. These other rubber components may be used alone or in combination of two or more.

[0226] (Content) The content of the butyl rubber in 100% by mass of the rubber component is preferably more than 90% by mass, more preferably more than 92% by mass, and even more preferably more than 95% by mass, from the viewpoint of sufficient air barrier properties.

[0227] <Filler> The filler may include recycled carbon black (rCB), carbon black other than rCB, or silica. When the filler includes silica, it may further include a silane coupling agent. The filler may further include other fillers other than carbon black and silica. The components that may constitute the filler are as described in the section on the rubber composition for the base tread.

[0228] (Carbon black content) The amount of recycled carbon black is, for example, more than 2 parts by mass, preferably more than 3 parts by mass, more preferably more than 5 parts by mass, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the amount is preferably less than 60 parts by mass, more preferably less than 55 parts by mass, and even more preferably less than 50 parts by mass. The total amount of recycled carbon black and other carbon black is, for example, more than 20 parts by mass, preferably more than 25 parts by mass, and more preferably 30 parts by mass or more, per 100 parts by mass of the rubber component. On the other hand, the total amount is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass. When the carbon black content is within the above range, sufficient reinforcement and good dispersion in the rubber are obtained, and sufficient rubber strength and fuel economy tend to be obtained.

[0229] (Silica content) When silica is contained, the same explanation as given for the rubber composition for the base tread can be applied to the content thereof per 100 parts by mass of the rubber component.

[0230] (Silane coupling agent content) When a silane coupling agent is contained, the content of the silane coupling agent can be similarly applied to the explanation given for the rubber composition for the base tread.

[0231] (Other compounding agents) The rubber composition preferably contains a resin. Regarding other details, the explanation given for the rubber composition for the base tread is similarly applicable.

[0232] The above is an explanation of each component when the tire components are composed of a rubber composition containing recycled carbon black. When the tire components are composed of a rubber composition that does not contain recycled carbon black, as described above, the above explanation can be applied by replacing the recycled carbon black in the above explanation with ordinary carbon black.

[0233] [Rubber composition for other tire components constituting the tire] For example, the explanation given for the rubber composition for the base tread can be similarly applied to rubber compositions constituting tire components other than the base tread, sidewall, clinch apex, insulation, and inner liner.

[0234] (Total styrene content in rubber components) In this embodiment, the total styrene amount (mass%) in the rubber component contained in each of the above rubber compositions is preferably less than 2.0. It is more preferably less than 1.5, even more preferably less than 1.0, even more preferably less than 0.50, even more preferably less than 0.40, even more preferably less than 0.30, and especially preferably less than 0.20. The total styrene amount in the rubber component may be 0. This can solve the problem of improving fuel economy.

[0235] In this specification, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining such various materials from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0236] <Manufacturing method> The tire according to the embodiment of the present invention can be manufactured by a known method.

[0237] (Production of rubber composition) Each of the above rubber compositions can be produced by a known method. For example, they can be produced by kneading the above components using a rubber kneading device such as an open roll or an internal kneader (e.g., a Banbury mixer or kneader). The kneading process may include, for example, a base kneading process in which compounding ingredients and additives other than the vulcanizing agent and vulcanization accelerator are kneaded, and a final kneading (F kneading) process in which the vulcanizing agent and vulcanization accelerator are added to the kneaded product obtained in the base kneading process and kneaded. Furthermore, the base kneading process can be divided into multiple processes as desired. The kneading conditions are not particularly limited, but examples include a method in which the base kneading process involves kneading for 3 to 10 minutes at a discharge temperature of 150 to 170°C, and a method in which the final kneading process involves kneading for 1 to 5 minutes at a discharge temperature of 50 to 110°C.

[0238] (tire manufacturing) Each rubber composition obtained above can be extruded in the unvulcanized state to match the shape of the desired tire component, thereby forming an unvulcanized base tread, sidewall, clinch apex, insulation, inner liner, etc. The tire according to the present embodiment can be formed into an unvulcanized tire by molding at least one of the thus obtained components, such as the base tread, sidewall, clinch apex, insulation, or inner liner, together with other tire components in a tire building machine using a conventional method. The unvulcanized tire can be obtained by heating and pressurizing (vulcanizing) it in a vulcanizer. The vulcanization conditions are not particularly limited, and examples thereof include vulcanization at 150 to 200°C for 5 to 30 minutes.

[0239] <Application> In this specification, the term "tire" refers to a tire that can be used for any purpose, regardless of whether it is a pneumatic tire or a 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. It is preferable to use the tire as an electric vehicle tire. Passenger car tires are tires designed to be mounted on four-wheeled vehicles and have a maximum load capacity of less than 1,400 kg. Heavy-duty tires are tires with a maximum load capacity of 1,400 kg or more. Electric vehicle tires are tires designed to be mounted on four-wheeled vehicles that are driven by an electric motor and whose main driving source is a secondary battery such as a lithium-ion battery. Electric vehicle tires also include tires that can use a fuel cell as a driving source. In this specification, the term "tire" refers to all-season tires, summer tires, and winter tires such as studless tires. [Example]

[0240] The following examples (working examples) are considered to be preferable for carrying out the present invention, but the scope of the present invention is not limited to these examples. Rubber compositions and tires obtained according to the tables were examined using the various chemicals shown below, and the results calculated based on the evaluation method described below are shown as durability indices at the bottom of each table.

[0241] <Material> The materials used in the examples and comparative examples will be summarized below. IR rubber 1: TSR20 (natural rubber) IR rubber 2: SVR-L (natural rubber) BR1: BR730 manufactured by JSR Corporation (high cis polybutadiene, cis content: 96 mol%) BR2: BR1250H manufactured by Zeon Corporation (tin-modified BR, polymerized using lithium as an initiator, cis content: 42 mol%, Mw: 570,000) SBR: SBR1502 manufactured by JSR Corporation (unmodified E-SBR, styrene content: 23.5% by mass, vinyl content: 18% by mole, Tg: -56°C, Mw: 440,000, non-oil extended) Butyl rubber: ExxonMobil Chlorobutyl HT1066 (chlorobutyl rubber) Carbon black 1: Show Black N351H (N2SA: 69m) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 29 nm, ash content: 1.0% by mass or less) Carbon black 2: Cabot Japan Co., Ltd.'s Show Black N550 (N2SA: 42m 2 / g, average primary particle diameter: 38nm, ash content: 1.0% by mass or less) Carbon black 3: Show Black N660 (N2SA: 35m) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 55 nm, ash content: 1.0% by mass or less) Carbon black 4: Show Black N330 (N2SA: 75 ml) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 30nm, ash content: 1.0% by mass or less) Recycled carbon black (rCB): Carbon black obtained from the pyrolysis process of tires (ash content: 17% by mass) Oil 1: Diana Process NH-70S (aromatic process oil) manufactured by Idemitsu Kosan Co., Ltd. Oil 2: PS-32 (mineral oil) manufactured by Idemitsu Kosan Co., Ltd. Resin: Tosoh Corporation's Petrotack 100V (C5 / C9 resin) Wax: Ozoace 0355 (paraffin-based) manufactured by Nippon Seiro Co., Ltd. Antioxidant: Nocrac 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Camellia stearic acid beads manufactured by NOF Corporation Sulfur: HK-200-5 (powdered sulfur, oil content: 5% by mass) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela CZ (N-cyclohexyl-2-benzothiazole sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela NS (N-tert-butyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 3: Noccela DM (di-2-benzothiazolyl disulfide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0242] <Tire using base tread rubber composition> According to the formulation shown in Table 1, a 1.7 L internal Banbury mixer was used to mix all the chemicals except for the sulfur and vulcanization accelerator for 5 minutes until the discharge temperature reached 170°C, yielding a kneaded mixture. Next, using a two-screw open roll, the sulfur and vulcanization accelerator were added to the mixture, and the mixture was mixed for 4 minutes until the temperature reached 105°C, yielding an unvulcanized rubber composition. The unvulcanized rubber composition was extruded into the shape of a base tread using an extruder equipped with a die of a predetermined shape, and then bonded together with other tire components to form an unvulcanized tire. This was then press-vulcanized for 12 minutes at 170°C to produce a test tire (tire size: 175 / 60R18, Wt: 181 mm, Dt: 662 mm, value of the left side of Equation (1): 1901).

[0243] <Tire using rubber composition for sidewall> According to the formulation shown in Table 2, a 1.7 L internal Banbury mixer was used to knead all chemicals except sulfur and the vulcanization accelerator for 5 minutes until the discharge temperature reached 170°C, yielding a kneaded mixture. Next, using a two-screw open roll, sulfur and the vulcanization accelerator were added to the kneaded mixture, and the mixture was kneaded for 4 minutes until the temperature reached 105°C, yielding an unvulcanized rubber composition. The unvulcanized rubber composition was extruded into the shape of a sidewall using an extruder equipped with a die of a predetermined shape, and then bonded together with other tire components to form an unvulcanized tire. This was then press-vulcanized for 12 minutes at 170°C to produce a test tire (tire size: 155 / 55R18, Wt: 164 mm, Dt: 628 mm, value of the left side of Equation (1): 1888).

[0244] <Tire using rubber composition for clinch apex> According to the formulation shown in Table 3, all chemicals except sulfur and vulcanization accelerators were mixed in a 1.7 L internal Banbury mixer for 5 minutes until the discharge temperature reached 170°C, yielding a kneaded mixture. Next, sulfur and vulcanization accelerators were added to the mixture using a two-screw open roll mill, and the mixture was mixed for 4 minutes until the temperature reached 105°C, yielding an unvulcanized rubber composition. The unvulcanized rubber composition was extruded into the shape of a clinch apex using an extruder equipped with a die of a predetermined shape. This was then bonded together with other tire components to form an unvulcanized tire, which was then press-vulcanized for 12 minutes at 170°C to produce a test tire (tire size: 155 / 55R18, Wt: 164 mm, Dt: 628 mm, value of the left side of Equation (1): 1888).

[0245] <Tire using rubber composition for insulation> According to the formulation shown in Table 4, chemicals other than sulfur and vulcanization accelerators were mixed in a 1.7 L closed-type Banbury mixer at a discharge temperature of 150°C for 5 minutes. The sulfur and vulcanization accelerator were then added to the resulting mixture, and the mixture was mixed in an open roll for 4 minutes until the temperature reached 105°C, yielding an unvulcanized rubber composition for an inner liner. The unvulcanized rubber composition for an inner liner was molded into a sheet and laminated with other tire components to form an unvulcanized tire. The tire was press-vulcanized for 12 minutes at 170°C to produce a test tire (tire size: 195 / 50R20, Wt: 197, Dt: 703 mm, value of the left side of formula (1): 1969).

[0246] <Tire using rubber composition for inner liner> According to the formulation shown in Table 5, chemicals other than sulfur and vulcanization accelerators were mixed in a 1.7 L closed-type Banbury mixer for 4 minutes until the discharge temperature reached 160°C, yielding a kneaded mixture. Next, sulfur and vulcanization accelerators were added to the resulting mixture using a two-screw open roll mill, and the mixture was mixed for 4 minutes until the temperature reached 80°C, yielding an unvulcanized rubber composition. The unvulcanized rubber composition was molded into the shape of an inner liner, bonded together with other tire components, and formed into an unvulcanized tire. The tire was press-vulcanized for 12 minutes at 170°C to produce test tires (tire size: 195 / 50R20, Wt: 197 mm, Dt: 703 mm, value of the left side of formula (1): 1969).

[0247] <Evaluation> The results of evaluation of each test tire according to the evaluation methods described below are shown in the corresponding columns of the tables below.

[0248] (low fuel consumption performance) Using a rolling resistance tester, each test tire was measured for rolling resistance when it was driven at a speed of 80 km / h with an internal pressure of 210 kPa and a load of 50 percent of its maximum load capacity, and the reciprocal of this was expressed as an index, with the reference comparative example being set at 100. The higher the value, the lower the rolling resistance and the better the fuel economy performance.

[0249] [Table 1]

[0250] [Table 2]

[0251] [Table 3]

[0252] [Table 4]

[0253] [Table 5]

[0254] <Embodiment> The following describes a preferred embodiment.

[0255] [1] A tire having at least one tire component made of a rubber composition containing recycled carbon black, When the thickness (mm) of the tire component is A, the total content (parts by mass) of carbon black contained in the rubber composition is B, the cross-sectional width (mm) of the tire is Wt, and the outer diameter (mm) of the tire is Dt, A, B, Wt, and Dt simultaneously satisfy the following formulas (1) and (2), and the right-hand side of formula (1) is preferably 1750. (1) (π / 4)×(Dt 2 / Wt)≧1700 (2) (Dt 2 / Wt) / (B×A)>20 [2] The tire according to [1], wherein the tire component is at least one tire component selected from a base tread, a sidewall, a clinch apex, an insulation, and an inner liner. [3] The tire according to [1] or [2], wherein the right side of formula (1) is 1800, more preferably 1850, even more preferably 1880, even more preferably 1900, even more preferably 1950, and even more preferably 2000. [4] The tire according to any one of [1] to [3], wherein the right side of formula (2) is 23, more preferably 25, even more preferably 30, even more preferably 35, even more preferably 40, and even more preferably 50. [5] The tire according to any one of [1] to [4], wherein the tire component is a base tread, the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass. [6] The tire according to any one of [1] to [4], wherein the tire component is a sidewall, the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass. [7] The tire according to any one of [1] to [4], wherein the tire component is a clinch apex, the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80 mass%. [8] The tire according to any one of [1] to [4], wherein the tire component is insulation, the rubber composition contains an isoprene-based rubber and a styrene-butadiene rubber, and the total content of the isoprene-based rubber and the styrene-butadiene rubber exceeds 80% by mass. [9] The tire according to any one of [1] to [4], wherein the tire component is an inner liner, the rubber composition contains a butyl-based rubber, and the content of the butyl-based rubber is more than 90 mass%.

[10] A tire according to any one of [1] to [9], having two or more circumferential main grooves extending in the tire circumferential direction on the tread surface of the tire, a pair of shoulder land portions on the outer side in the tire width direction defined by a pair of outermost circumferential main grooves located on the outermost sides in the tire width direction among the circumferential main grooves, and a center land portion sandwiched between the pair of shoulder land portions, wherein the negative ratio of the center land portion is greater than 0% and less than 15%, preferably greater than 2% and less than 14%, more preferably greater than 4% and less than 13%, and even more preferably greater than 6% and less than 12%.

[11] The tire according to

[10] , wherein the negative ratio of the shoulder land portion is more than 20%, preferably more than 23%, more preferably more than 25%, even more preferably more than 28%, and still more preferably more than 30%.

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

[11] , wherein the total styrene amount (mass%) in the rubber component contained in the rubber composition is less than 2.0, preferably less than 1.5, more preferably less than 1.0, even more preferably less than 0.50, even more preferably less than 0.40, even more preferably less than 0.30, and even more preferably less than 0.20.

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

[12] , wherein the content of silica contained in the rubber composition is less than 10 parts by mass per 100 parts by mass of the rubber component.

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

[13] , wherein the rubber composition contains a resin.

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

[14] , which is a tire for an electric vehicle. [Explanation of symbols]

[0256] 1 Base Tread 2. Insulation 3 Inner liner 4 Sidewall 5 Clinch Apex 41 Outermost circumferential main groove 42 Circumferential groove 43 Center Land Division 45 Shoulder land area CL Tire equatorial plane R rim T1 Base tread thickness T2 Insulation Thickness T3 Inner liner thickness T4 Sidewall Thickness T5 Clinch Apex Thickness

Claims

1. A tire having at least one tire component constructed from a rubber composition including recycled carbon black, A tire in which A, B, Wt, and Dt simultaneously satisfy the following formulas (1) and (2), where A is the thickness (mm) of the tire component, B is the total content (parts by mass) of carbon black contained in the rubber composition, Wt is the cross-sectional width (mm) of the tire, and Dt is the outer diameter (mm) of the tire: (1) (π / 4)×(Dt 2 / Wt)≧1700 (2) (Dt 2 / Wt) / (B×A)>20

2. 2. The tire of claim 1, wherein the tire component is at least one tire component selected from a base tread, a sidewall, a clinch apex, an insulation, and an inner liner.

3. The tire according to claim 1 or 2, wherein the right side of formula (1) is 1800.

4. The tire according to claim 1 or 2, wherein the right side of formula (2) is 23.

5. the tire component is a base tread, The tire according to claim 1 or 2, wherein the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass.

6. the tire component is a sidewall, The tire according to claim 1 or 2, wherein the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass.

7. the tire component is a clinch apex, The tire according to claim 1 or 2, wherein the rubber composition contains an isoprene-based rubber and a butadiene rubber, and the total content of the isoprene-based rubber and the butadiene rubber exceeds 80% by mass.

8. the tire component is an insulation, The tire according to claim 1 or 2, wherein the rubber composition contains an isoprene-based rubber and a styrene-butadiene rubber, and the total content of the isoprene-based rubber and the styrene-butadiene rubber exceeds 80% by mass.

9. the tire component is an inner liner, The tire according to claim 1 or 2, wherein the rubber composition contains a butyl-based rubber, and the content of the butyl-based rubber is more than 90% by mass.

10. 3. The tire according to claim 1, further comprising: two or more circumferential main grooves extending in the tire circumferential direction on the tread surface of the tire; a pair of shoulder land portions on the outer sides in the tire width direction defined by a pair of outermost circumferential main grooves located on the outermost sides in the tire width direction among the circumferential main grooves; and a center land portion sandwiched between the pair of shoulder land portions, wherein the negative ratio of the center land portion is greater than 0% and less than 15%.

11. The tire according to claim 10, wherein the negative ratio of the shoulder land portion is greater than 20%.

12. The tire according to claim 1 or 2, wherein a total amount (mass %) of styrene in a rubber component contained in the rubber composition is less than 2.

0.

13. The tire according to claim 1 or 2, wherein the content of silica contained in the rubber composition is less than 10 parts by mass per 100 parts by mass of the rubber component.

14. The tire according to claim 1 or 2, wherein the rubber composition contains a resin.

15. The tire according to claim 1 or 2, which is a tire for an electric vehicle.

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