TIRES

Abstract

A pneumatic tire is provided which comprises a tread portion, wherein the tread portion is composed of a rubber composition comprising a rubber component and silica, wherein a content of an isoprene-based rubber in the rubber component is greater than 40 mass%, wherein a content of silica based on 100 mass parts of the rubber component in the rubber composition is greater than 30 mass parts, wherein, when 30°C-ΔE* (0.25% - 1.0%) represents a difference between a complex elastic modulus at a dynamic strain of 0.25% and a complex elastic modulus at a dynamic strain of 1.0%, measured under a condition of a temperature of 30°C, a frequency of 10 Hz, and an initial strain of 5%, of the rubber composition, and T in mm represents a thickness of the tread portion, 30°C-ΔE* (0.25% - 1.0%) - 1.0%) is 6.0 MPa or more and 30 °C-ΔE* (0.25% - 1.0%) / T is 0.45 or more.,

Description

TECHNICAL FIELDThe present invention relates to a tire.BACKGROUND OF THE INVENTIONRecently, in a pneumatic tire, from the viewpoint of fuel efficiency, etc., attempts have been made to reduce heat generation of a tire by bonding a modified styrene-butadiene rubber or silica (for example, JP 2014-80521 A).SUMMARY OF THE INVENTIONOn the other hand, with recent advances in highway construction, it is not uncommon to travel long distances at high speeds, and a pneumatic tire has been required to have steering stability during high-speed running.An object of the present invention is to provide a pneumatic tire having improved steering stability during high-speed running.The present invention relates to:a pneumatic tire comprising a tread portion,wherein the tread portion is constructed from a rubber composition comprising a rubber component and silica,wherein a content of an isoprene-based rubber in the rubber component is greater than 40 mass %,wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, andwherein, when 30° C.-ΔE* (0.25%-1.0%) represents a difference between a complex elastic modulus at a dynamic strain of 0.25% and a complex elastic modulus at a dynamic strain of 1.0% measured under a condition of a temperature at 30° C., a frequency of 10 Hz, and an initial strain of 5%, of the rubber composition, and T in mm represents a thickness of the tread portion, 30° C.-ΔE* (0.25%-1.0%) is 6.0 MPa or more, and 30° C.-ΔE* (0.25%-1.0%) / T is 0.45 or more.According to the present invention, there is provided a pneumatic tire having improved steering stability during high-speed running.BRIEF DESCRIPTION OF THE FIGURESFIG. 1 is a schematic development view of a tread portion of a tire according to an embodiment of the present invention. FIG. 2 is a schematic development view of a tread portion of a tire according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a part of a tread portion of a tire according to an embodiment of the present invention taken along a plane passing through a tire rotation axis.DETAILED DESCRIPTIONThe tire according to an embodiment of the present invention is a pneumatic tire including a tread portion, the tread portion being composed of a rubber composition including a rubber component and silica, wherein a content of an isoprene-based rubber in the rubber component is greater than 40 mass %, wherein a content of silica based on 100 mass parts of the rubber component in the rubber composition is greater than 30 mass parts, wherein when 30° C.-ΔE* (0.25%-1.0%), a difference between a complex elastic modulus at a dynamic strain of 0.25% and a complex elastic modulus at a dynamic strain of 1.0% measured under a condition of a temperature at 30° C., a frequency of 10 Hz, and an initial strain of 5% is determined, The rubber composition is selected from the group consisting of: and T in mm is a thickness of the tread portion, 30° C.-ΔE* (0.25%-1.0%) is 6.0 MPa or more, and 30° C.-ΔE* (0.25%-1.0%) / T is 0.45 or more.Although not intended to be bound by any theory, for example, the following may be considered as a mechanism for improving steering stability during high-speed running in the pneumatic tire of the present invention.Since silica is a hydrophilic filler, (1) when the rubber component comprises an isoprene-based rubber and a content of silica based on 100 parts by mass of the rubber component is more than 30 parts by mass, a polymer chain present around silica can be reinforced, and a region in which silica is aggregated with each other can be formed when silica is compounded into the isoprene-based rubber. Therefore, it becomes possible to increase 30° C.-ΔE* (0.25%-1.0%).During high-speed running, the tire reaches a state in which a ground contact surface of the tread portion that comes into contact with a road surface undergoes a large amount of deformation when a weight of a vehicle is applied to irregularities of the road surface while the inner space of the tread portion undergoes a relatively small amount of deformation when the weight of the vehicle is applied for a short period of time due to high-speed running. Therefore, (2) by setting 30° C.-ΔE* (0.25%-1.0%) to 6.0 MPa or more, a state in which a complex elastic modulus for a small deformation is high and a state in which the complex elastic modulus for a large deformation is low can be maintained, so that responsiveness can be improved while improving followability of the ground contact surface of the tread portion with respect to the road surface. Moreover, since a strength of a rubber molecule in the isoprene-based rubber is high, (3) by setting the content of the isoprene-based rubber in the rubber component to more than 40 mass %, a reaction force at the time of reaction is increased. Further, (4) by increasing 30° C.-ΔE* (0.25%-1.0%) relative to the thickness T in mm of the tread portion and setting 30° C.-ΔE* (0.25%-1.0%) / T to 0.45 or more rigidity of the entire tread portion can be improved while shortening a transmission distance of a force from one introduction to one reaction.Then, it is considered that, with cooperation of the above-described (1) to (4), a remarkable effect of improving steering stability during high-speed running is achieved.It is preferable that the rubber composition comprises carbon black and that a content of carbon black based on 100 parts by mass of the rubber component in the rubber composition is greater than 1 part by mass and less than 25 parts by mass.When the content of carbon black is within the above-described range, the content of silica can be increased, so that it is facilitated to obtain the effect of reinforcing the polymer chain by silica, so that it is considered that steering stability during high-speed running is further improved.The rubber composition preferably has a rubber hardness of greater than 50 and less than 80. When the rubber hardness is within the above-described range, it is considered that steering stability during high-speed running is further improved.It is preferable that the tread portion has one or more side grooves extending in a tire width direction, and a total volume of the one or more side grooves is 2.0% or more and 5.0% or less of a volume of the tread portion. Movement of the tread portion is thereby suppressed, so that it is considered that steering stability during high-speed running is further improved.It is preferable that the tread portion has one or more circumferential grooves extending in a tire circumferential direction, and wherein in one of the one or more circumferential grooves, a ratio (L 80 / L 0) of a groove width L 80 at an 80% position of a groove depth of the deepest portion of the circumferential groove to a groove width L 0 at the ground contact surface of the tread portion is 0.3 or more and 0.7 or less. Movement of the entire land portion on the bottom surface of the land portion of the tread portion can be suppressed thereby, so that it is considered that steering stability during high-speed running is further improved.It is preferable that the tread portion has a groove inclined in a tire circumferential direction or a tire width direction, and that a maximum width L of the groove inclined in the tire circumferential direction or the tire width direction is greater than 7.0 mm and less than 20.0 mm.By providing the tread portion with the groove inclined in the tire circumferential direction or the tire width direction, responsiveness can be improved while followability of the ground contact surface of the tread portion with respect to the road surface is improved, so that it is considered that steering stability during high-speed running is further improved.It is preferred that T be greater than 6.0 mm and less than 12.0 mm. When the thickness of the tread portion is within the above-described range, responsiveness can be improved while following ability of the tread ground contact surface to the road surface is improved, so that it is considered that steering stability during high-speed running is further improved.<>A "standardized state" is a state in which a tire is rim-mounted on a standardized rim and a standardized internal pressure is filled and no load is applied. Unless otherwise specified, a tire in the standardized state is used.A "dimension of each part of the tire" is, unless otherwise specified, a value specified in a standardized state for one appearing on the outer surface of the tire, while one existing inside the tire or one on a tire cut surface is a value specified in a state in which, for example, the tire is cut along a plane including a tire rotation axis and the cut tire piece is held to a rim width of a standardized rim.A "standardized rim" is a rim in a standard system containing a standard on which the tire is based, which is defined by the standard for each tire. For example, the "standardized rim" refers to a standard rim of an applicable size described in "JATMA" described in JATMA (The Japan Automobile Tire Manufacturers Association, Inc.), "JATMA YEAR BOOK", "Measuring Rim" described in "STANDARDS MANUAL" described in ETRTO (The European Tire and Rim Technical Organization) or "Design Rim" described in "YEAR BOOK" described in TRA (The Tire and Rim Association, Inc.), referred to in this order, and when there is an applicable size at the time of reference, The rim conforms to its standard. In addition, in a case of tires not defined by the standard, the standardized rim is intended to refer to a rim that can be mounted on the tire and whose width is narrowest among rims having the smallest diameter that can maintain an internal pressure (i.e., does not cause air leakage between the rim and the tire).A "standardized internal pressure" is an air pressure in a standard system including a standard on which the tire is based, which is defined by the standard for each tire, for example, refers to a "MAXIMUM AIR PRESSURE" in JATMA, "INFLATION PRESSURE" in ETRTO, or a maximum value described in Table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in TRA referred to in this order as in the case of the standardized rim, and when there is an applicable quantity at the time of reference, the standardized internal pressure conforms to its standard. In addition, in a case of tires not defined by the standard, the standardized internal pressure is intended to refer to a standardized internal pressure (250 KPa or more) of another tire size (specified in the standard) for which the standardized rim is described as a standard rim, and when a plurality of standardized internal pressures of 250 KPa or more are described, is intended to refer to a minimum value below.A "standardized load in kg" is a load in a standard system including a standard on which the tire is based, defined by the standard for each tire, for example, a "MAXIMUM LOAD CAPACITY" in JATMA, a "LOAD CAPACITY" in ETRTO, or a maximum value described in Table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in TRA referred to in this order as in cases of a standardized rim and a standardized internal pressure, and when there is an applicable quantity at the time of reference, the load conforms to its standard. Then, in a case of a tire not specified in the above-described standard, the separately calculated maximum load capacity W L is defined as a standardized load.The "maximum load capacity W L in kg" is calculated by the following equations, where "V" is a virtual volume in mm3of a tire, "Dt" is a tire outer diameter in mm in a standardized state, "Ht" is a tire cross-sectional height in mm in a tire radial direction in a cross section of the tire in a plane including a tire rotational axis, and "Wt" is a tire cross-sectional width in mm in a standardized state. When R represents a rim diameter of the tire, Ht may be calculated by (Dt-R) / 2. Wt is a value obtained by excluding patterns or characters on the side surface of the tire, if present. In addition, the "maximum load capacity" has the same meaning as the standardized load described above.A "thickness T in mm of a tread portion" is a thickness of the entire tread portion as measured along a normal to a tread ground contact surface on a tire equator in a cross section passing through a tire rotation axis. In a case where a circumferential groove is present on a tire equator, the thickness T is a thickness measured along a normal to a tread ground contact surface on a center portion in a tire width direction of a land portion in which the center portion in the tire width direction of the land portion is closest to a tire equatorial plane, of land portions present on both side surfaces in a tire width direction of the groove.A "groove" refers to, among recessed portions formed at a tread portion of a tire, one having an opening width of 2.0 mm or more at a tread ground contact surface of the groove. Among the depressed portions, one having an opening width of less than 2.0 mm at the tread ground contact surface refers to a "sipe".A "circumferential groove" refers to a groove extending in a tire circumferential direction. The circumferential groove may extend linearly along a circumferential direction or may extend wave-shaped, sinusoidal-shaped or zigzag-shaped along the circumferential direction.A "groove depth" refers to a maximum value of a distance between a straight line connecting ends of the groove on a tread ground contact surface and the deepest portion of the groove in a tire radial direction. In a case where the groove depth of the groove varies in a tire width direction or a circumferential direction, this maximum value is defined as a groove depth of the groove. Moreover, a depth at a point of three or more intersection points at which a plurality of grooves intersect is excluded from the groove depth.A "side groove" refers to a groove extending in a tire width direction. Here, "extending in a tire width direction" means that an angle formed by a line segment connecting the start point and the end point and the tire width direction is less than 45°. When the groove extends to a tread end, the tread end is to be the start or end point. A "volume of a side groove" is a value of volume defined by an area connecting ends of the side groove in a tire width direction and a groove wall in a tire in a standardized state. A "total volume of side grooves" can be calculated by determining volumes of individual side grooves.A "volume of a tread portion" refers to a volume of the tread portion on the assumption that all the grooves of the tread portion are filled. The "tread portion" herein is a portion that forms a ground contact surface of a tire, and in a case where the tire includes a member that forms a tire skeleton of steel or a textile material such as a belt layer, a belt reinforcing layer, a carcass layer, and the like in a cross section in a tire radial direction, a member on an outer side thereof in the tire radial direction.A "groove width L 0 of a circumferential groove at a ground contact surface of a tread portion" is a width in mm of the circumferential groove at a tread ground contact surface in a tire rotational axis direction measured in a standardized state. A "groove width L 80 at 80% position of the deepest portion of a circumferential groove" is a width in mm at 80% position of the deepest portion of the circumferential groove in a tire rotational axis direction measured in a standardized state.A "groove depth of the deepest portion of a circumferential groove" is a groove depth of a circumferential groove having the deepest groove depth when a plurality of circumferential grooves are present.A "maximum width of an inclined groove" refers to the maximum width among the opening widths of grooves at a tread ground contact surface in a cross section perpendicular to a center line of both ends of a tread extending in an extending direction of a groove. An opening width is a distance from one tread end to the other tread end on the tread ground contact surface. Here, an "extending direction of a groove" refers to a direction in which the groove continuously extends, for example, a circumferential direction in a case of a circumferential groove, and a direction along the inclination in the tire width direction in a case of a groove inclined in a tire width direction.A "styrene content in mass % of a rubber component" is obtained by multiplying a styrene content of each rubber constituting the entire rubber component in 100 mass % by its content occupying the entire rubber component and adding all of them.A "vinyl content in mass % of a rubber component" is obtained by multiplying a content of vinyl butadiene unit derived from 1.2 carbon atoms bond of each rubber constituting the entire rubber component in 100 mass % with its content occupying the entire rubber component and adding all of them.A "rubber component of a rubber composition" is a component that contributes to crosslinking in the rubber composition and generally has a weight average molecular weight (Mw) of 10,000 or more.<>„30 The ° C-E* at a dynamic strain of 0.25 %" is a complex elastic modulus measured using a viscoelasticity measurement device (e.g., EPLEXOR series manufactured by gabo System Technique GmbH) under a condition of a temperature at 30 ° C., a frequency of 10 Hz, an initial strain of 5 %, a dynamic strain of ± 0.25 %, and a strain mode. When a sample for measuring complex elastic modulus is produced by being cut out from a tire, it is cut out from a tread portion of the tire so that a tire radial direction becomes a thickness direction.„30 The ° C-E* at a dynamic strain of 1.0%" is a complex elastic modulus measured using a viscoelasticity measurement device (e.g., EPLEXOR series manufactured by gabo Systemtechnik GmbH) under a condition of a temperature at 30° C., a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1.0%, and a strain mode. A sample for measurement is produced in a similar manner as in the case of 30° C-E* at a dynamic strain of 0.25%.„30 °C - ΔE* (0.25% - 1.0%)" can be determined from a difference between 30°C-E* at a dynamic strain of 0.25% and 30°C-E* at a dynamic strain of 1.0%.A "rubber hardness" is a value obtained by cutting a tread portion from a tread portion forming a ground contact surface such that a tire radial direction becomes a thickness direction to prepare a sample for measuring hardness, and by pressing a type A durometer against the sample from the ground contact surface side at 23° C. according to JIS K 6253.A "glass transition temperature (Tg) of a rubber component" is measured by measurement while raising temperature at a temperature rise rate of 10° C. / min using a differential scanning calorimeter (Q200) manufactured by TA Instruments Japan Inc. in accordance with JIS K 7121.An "average primary particle size" is calculated by an arithmetic mean of particle sizes of 400 particles photographed with a transmission or scanning electron microscope. With respect to the particle size, in a case where the particle is in a substantially circular shape, a diameter of the circle is defined as a particle size, in a case where it is in a needle or rod shape, a minor axis is defined as a particle size, and in the other cases, an equivalent circle diameter calculated from an electron microscopic image is defined as a particle size. The equivalent circle diameter is calculated as "positive square root of 4×(particle area) / π". The average primary particle size is applied to silica, carbon black, etc.A "nitrogen adsorption specific surface area (N 2 SA) of carbon black" is measured according to JIS K 6217-2:2017.A "nitrogen adsorption specific surface area (N 2 SA) of silica" is measured by the BET method according to ASTM D3037-93.A "styrene content" is a value calculated by 1 H-NMR measurement, and is applied to, for example, a rubber component having a repeating unit derived from styrene, such as an SBR and the like. A "cis content (cis-1,4-bound butadiene unit amount)" is a value calculated according to JIS K 6239-2:2017 by infrared absorption spectrometry, and is applied to a rubber component having a repeating unit derived from butadiene, such as a BR and the like.A "softening point of a resin component" is specified as a temperature at which a ball falls when the softening point defined in JIS K 6220-1:2015 7.7 is measured with a ring-and-ball softening point measuring device.A "content of a softening agent" also includes an amount of a softening agent contained in a stretched rubber component that has been previously stretched with the softening agent, such as oil, a resin component, a liquid rubber component, and the like. The same applies to, for example, a content of oil, a content of a resin component, and a content of a liquid rubber, and for example, a extender oil is contained in the content of oil when an extender component is oil.A procedure for producing a pneumatic tire, which is an embodiment of the present invention, will be described in detail below. However, the following descriptions are illustrative of the explanation of the present invention and are not intended to limit the technical scope of the present invention only to this range of description. In addition, in the present specification, a numerical range identified with "to" means including the numerical values from both ends.<Reifen>FIG. 1 is a schematic view of a ground contact surface when a tread portion of a tire, which is an embodiment of the present invention, is pressed against a flat surface. A tread portion 10 has a plurality of circumferential grooves 1. In FIG. 1, three circumferential grooves 1 are provided, although the number of circumferential grooves is not particularly limited and may be, for example, two to five.The tread portion 10 includes land portions 2 separated by a plurality of circumferential grooves 1 in a tire width direction W. A shoulder land portion 11 is a pair of land portions formed between the circumferential groove 1 and the tread end Te. A central land portion 12 is a land portion formed between a pair of shoulder land portions 11. In FIG. 1, two middle land portions 12 are provided, although the number of middle land portions is not particularly limited and may be, for example, one to five.FIG. 2 is a schematic development view of a tread portion of a tire which is another embodiment of the present invention. In FIG. 2, the tread portion 10 has a plurality of zigzag-shaped circumferential grooves 1 continuously extending in a circumferential direction. A side groove 5 is inclined so as to shift toward a side in a tire circumferential direction as it moves toward a center portion in a tire width direction. Then, the side groove 5 extends over the circumferential groove 1 at a bent portion of the circumferential groove 1. Moreover, the shoulder land portion 11 is provided with a plurality of linear shoulder sipes 22 having an end opened to the circumferential groove 1, and the center land portion 12 is provided with a plurality of linear center sipes 23 having an end opened to the circumferential groove 1. In addition, in the present embodiment, the circumferential grooves 1 do not necessarily have to be continuously located in the circumferential direction without discontinuity, and may be divided by the side grooves 5.The tread portion according to the present embodiment preferably has one or more side grooves from the viewpoint of steering stability during high-speed running. A total volume of the one or more side grooves is preferably 1.5% or more, more preferably 2.0% or more, and even more preferably 2.5% or more of the volume of the tread portion. Moreover, the total volume of the one or more side grooves is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 5.0% or less of the volume of the tread portion. When the total volume of the side grooves at the volume of the tread portion is within the above-described ranges, it is considered that steering stability during high-speed running is further improved.The maximum width L of the groove inclined in the tire circumferential direction or the tire width direction is preferably greater than 7.0 mm, more preferably greater than 8.0 mm, and even more preferably greater than 9.0 mm from the viewpoint of steering stability during high-speed running. On the other hand, an upper limit of the maximum width L is preferably less than 20.0 mm, and more preferably less than 15.0 mm, but is not particularly limited.FIG. 3 is a cross-sectional view passing through a tire rotation axis of a tire according to the present embodiment and showing a part of the tread portion. In FIG. 3, the tread portion is composed of a first layer 3 and a second layer 4, but it is not limited to such an aspect, and the tread portion may be, for example, a single rubber layer or may be three or more rubber layers.The thickness T of the tread portion of the pneumatic tire according to the present embodiment is preferably greater than 6.0 mm, more preferably greater than 8.0 mm, even more preferably 10.0 mm or more, and even more preferably 12.0 mm or more. Moreover, the thickness T of the tread portion is preferably 18.0 mm or less, more preferably 15.0 mm or less, and even more preferably 14.0 mm or less.It is preferable from the viewpoint of steering stability during high-speed running that a groove width of any of the circumferential grooves of the tread portion according to the present embodiment on an inner side in a tire radial direction is narrower than a groove width at a ground contact surface 6 of the tread portion. The ratio (L 80 / L 0) of the groove width L 80 at the 80% position of the groove depth of the deepest portion of the circumferential groove to the groove width L 0 of the circumferential groove that is narrower on the inner side in the tire radial direction than the groove width at the ground contact surface 6 of the tread portion is preferably 0.20 or more, more preferably 0.30 or more, and even more preferably 0.40 or more. Moreover, L is 80 / L is 0 preferably 0.80 or less, more preferably 0.70 or less, and even more preferably 0.60 or less.30 The ° C-E* at the dynamic elongation of ±0.25% of the rubber composition constituting the tread portion according to the present embodiment is preferably 19.0 MPa or more, more preferably 20.0 MPa or more, even more preferably 22.0 MPa or more, and even more preferably 23.0 MPa or more. Moreover, at the dynamic strain of ±0.25%, 30° C-E* is preferably 28.0 MPa or less, more preferably 26.0 MPa or less, and even more preferably 25.0 MPa or less.30 ° C-E* of the dynamic elongation of ±1.0% of the rubber composition constituting the tread portion according to the present embodiment is preferably 13.0 MPa or more, more preferably 14.0 MPa or more, even more preferably 15.0 MPa or more, and even more preferably 16.0 MPa or more. Moreover, at the dynamic strain of ±1.0%, 30° C-E* is preferably 20.0 MPa or less, more preferably 18.0 MPa or less, and even more preferably 17.0 MPa or less.30 °C ΔE* (0.25%-1.0%) of the rubber composition constituting the tread portion according to the present embodiment is 6.0 MPa or more, preferably 6.5 MPa or more, more preferably 6.8 MPa or more, even more preferably 7.0 MPa or more, even more preferably 7.2 MPa or more, even more preferably 7.5 MPa or more, even more preferably 7.8 MPa or more, and particularly preferably 8.0 MPa or more. Moreover, an upper limit value of 30° C.-ΔE* (0.25%-1.0%) of the rubber composition constituting the tread portion according to the present embodiment is not particularly limited, but may be, for example, 12.0 MPa or less, 10.0 MPa or less, 9.0 MPa or less, etc.In addition, 30° C.-E* can be adjusted appropriately depending on types and compounding amounts of a rubber component, a filler, a plasticizer, and the like described later. For example, 30° C.-E* can be increased by increasing an amount of the filler, decreasing a content of the softening agent, or the like in the rubber composition.30 The °C ΔE* (0.25%-1.0%) / T of the rubber composition constituting the tread portion according to the present embodiment is 0.45 or more, preferably 0.50 or more, more preferably 0.60 or more, still more preferably 0.70 or more, and particularly preferably 0.75 or more. Moreover, an upper limit value of 30° C.-ΔE* (0.25%-1.0%) / T is not particularly limited, but may be, for example, 1.00 or less, 0.95 or less, 0.90 or less, etc.The rubber hardness of the rubber composition constituting the tread portion according to the present embodiment is preferably greater than 50, more preferably greater than 55, and even more preferably greater than 60, from the viewpoint of riding comfort.In addition, the rubber hardness can be adjusted appropriately depending on types and compounding amounts of a rubber component, a filler, a softening agent, and the like described later. For example, the rubber hardness can be improved by increasing an amount of the filler or by decreasing a content of the softening agent in the rubber composition.The tread portion of the present invention has at least one rubber layer. The rubber layer may be formed of a single rubber layer, preferably includes a rubber layer that comes into contact with a road surface (a first layer) and a rubber layer that abuts a belt layer (a second layer) when the tire is used, and further may include one or more rubber layers between the first layer and the second layer.Any physical property value, such as 30° C.-ΔE* (0.25%-1.0%) and the like, of the rubber composition constituting the tread portion may satisfy a physical property value in any of the rubber layers, preferably in the first layer, in a case where the tread portion includes two or more rubber layers.< Component>The rubber composition constituting the tread portion according to the present embodiment (hereinafter, unless otherwise specified, referred to as the rubber composition according to the present embodiment) includes an isoprene-based rubber, preferably includes an isoprene-based rubber and a butadiene rubber (BR), and further preferably includes an isoprene-based rubber, a BR, and a styrene-butadiene rubber (SBR) as rubber components. Further, it may comprise rubber components other than those listed above. In addition, the rubber component may be a rubber component composed of an isoprene-based rubber, a BR, and an SBR.(Isoprene-based rubber)As an isoprene-based rubber, for example, those common in the tire industry such as an isoprene rubber (IR), a natural rubber, and the like can be used. Examples of the natural rubber include an unreformed natural rubber (NR), as well as a refined natural rubber such as an epoxidized natural rubber (ENR), a hydrogenated natural rubber (HNR), a deproteinized natural rubber (DPNR), and an ultra-pure natural rubber, a grafted natural rubber, and the like. These isoprene-based rubbers may be used alone, or two or more thereof may be used in combination.An NR is not particularly limited, and those common in the tire industry may be used, examples of which include, for example, SIR20, RSS#3, TSR20, and the like.A content of the isoprene-based rubber in the rubber component is more than 40 mass %, preferably 45 mass % or more, more preferably 48 mass % or more, and even more preferably 50 mass % or more, from the viewpoint of the effects of the present invention. On the other hand, the content of the isoprene-based rubber in the rubber component is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 70% by mass or less.(BR)A BR is not particularly limited, and those common in the tire industry may be used, such as a BR having a cis content of less than 50 mol % (a cis-poor BR), a BR having a cis content of 90 mol % or more (a cis-rich BR), a rare earth-based butadiene rubber synthesized using a rare earth element-based catalyst (a rare earth-based BR), a BR containing a syndiotactic polybutadiene crystal (a SPB-containing BR), a modified BR (a cis-rich modified BR, a cis-poor modified BR), and the like. These BRs may be used alone, or two or more thereof may be used in combination.As the cis-rich BR, for example, those commercially available from Zeon Corporation, UBE Corporation, JSR Corporation, etc. can be used. When the cis-rich BR is joined, low temperature properties and abrasion resistance can be improved. The cis content of the cis-rich BR is preferably 95 mol % or more, more preferably 96 mol % or more, and even more preferably 97 mol % or more. In addition, the cis content of the BR is measured by the above-described measurement method.A content of a BR, when combined, in the rubber component is preferably 5 mass % or more, more preferably 10 mass % or more, and even more preferably 15 mass % or more from the viewpoint of the effects of the present invention. On the other hand, the content of the BR, when combined, in the rubber component is preferably 60 mass % or less, more preferably 50 mass % or less, even more preferably 40 mass % or less, even more preferably 30 mass % or less, and particularly preferably 20 mass % or less.(SBR)An SBR is not particularly limited, examples thereof include a solution-polymerized SBR (S-SBR), an emulsion-polymerized SBR (E-SBR), modified SBRs (a modified S-SBR, a modified E-SBR) thereof, and the like. Examples of the modified SBR include an SBR modified at its end and / or main chain, a modified SBR coupled with tin, a silicon compound, etc. (a modified SBR of condensate or having a branched structure, etc.), and the like. Among them, an S-SBR and a modified SBR are preferable. Further, hydrogenated ones of these SBRs (hydrogenated SBRs) and the like can also be used. These SBRs may be used alone, or two or more thereof may be used in combination.A styrene content of an SBR is preferably 70 mass % or less, more preferably 60 mass % or less, even more preferably 50 mass % or less, and particularly preferably 45 mass % or less. Moreover, the styrene content of the SBR is preferably 15 mass % or more, more preferably 20 mass % or more, still more preferably 25 mass % or more, particularly preferably 30 mass % or more, and particularly preferably 35 mass % or more. In addition, the styrene content of the SBR is measured by the above-described measurement method.A glass transition temperature (Tg) of an SBR is preferably -60° C. or higher, more preferably -50° C. or higher, and even more preferably -40° C. or higher from the viewpoint of abrasion resistance. Moreover, the Tg of the SBR is preferably -20° C. or lower, more preferably -25° C. or lower, and even more preferably -30° C. or lower.A content of an SBR, when combined, in the rubber component is preferably 10 mass % or more, more preferably 20 mass % or more, still more preferably 30 mass % or more, and particularly preferably 32 mass % or more. On the other hand, the content of the SBR in the rubber component is preferably 60 mass % or less, more preferably 50 mass % or less, even more preferably 40 mass % or less, even more preferably 35 mass % or less, and particularly preferably 30 mass % or less.(Other Rubber Components)The rubber component may also include rubber components other than the above-described components as long as the effects of the present invention are not impaired, examples thereof include, for example, non-diene-based rubbers such as hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, and the like.(Rubber component synthesized from recycled / biomass-derived raw material)A monomer that is a structural unit of a synthetic rubber such as an SBR, a BR, and the like may be one derived from underground resources such as petroleum, a natural gas, and the like, or a recycled one of a rubber product such as a tire and the like, or a non-rubber product such as polystyrene and the like. A recycled monomer (recycled monomer) is not particularly limited, examples thereof include a recycled polyisoprene, a recycled butadiene, a recycled aromatic vinyl compound, and the like. Examples of the butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The above-described aromatic vinyl compound is not particularly limited, and examples thereof include styrene and the like. Among them, a recycled polyisoprene (a recycled polyisoprene), a recycled butadiene (a recycled butadiene), and / or a recycled styrene (a recycled styrene) are preferably used as a raw material.A method of producing a recycled monomer is not particularly limited, examples thereof include, for example, a method of synthesizing a monomer from a recycled naphtha obtained by decomposing a rubber product such as a tire and the like. Moreover, a method of producing a recycled naphtha is not particularly limited, and a recycled naphtha can be obtained, for example, by decomposing a rubber product such as a tire and the like under high temperature and high pressure, decomposing it by microwaves, or extruding it after mechanically pulverizing it.Further, a monomer that is a structural unit of a polymer such as an IR, an SBR, a BR, and the like may be a biomass-derived monomer. In the present specification, biomass refers to a material derived from natural sources such as plants and the like. Biomass is not particularly limited, examples thereof include, for example, agricultural, forest and fishing products, sugars, waste wood, a plant residue after detection of a useful component, an ethanol derived from plants, a biomass naphtha, and the like.The biomass-derived monomer (biomass monomer) is not particularly limited, examples thereof include a biomass-derived butadiene, a biomass-derived aromatic vinyl compound, and the like. Examples of the butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The above-described aromatic vinyl compound is not particularly limited, and examples thereof include styrene and the like. Moreover, a method of producing a biomass monomer is not particularly limited, examples thereof include, for example, one by biological and / or chemical and / or physical conversion of animals and plants, and the like. Microbial fermentation is representative of biological conversion, and examples of chemical and / or physical conversion include one due to catalyst, one due to high heat, one due to high pressure, one due to electromagnetic wave, one due to critical fluid, and combinations thereof.A polymer (biomass polymer) synthesized from a biomass monomer component is not particularly limited, examples thereof include a polybutadiene rubber synthesized from a biomass-derived butadiene, an aromatic vinyl / butadiene copolymer synthesized from a biomass-derived butadiene and / or a biomass-derived aromatic vinyl compound, and the like. Examples of the aromatic vinyl butadiene copolymer include, for example, a styrene-butadiene rubber synthesized from a biomass-derived butadiene and / or a biomass-derived styrene, and the like.Whether a raw material of a polymer is derived from biomass can be determined by pMC (percentage of modern carbon) measured according to ASTM D 6866-10. Here, pMC is a ratio of 14 C concentration of a sample to 14 C concentration of a modern standard carbon, and a value uses this value as an index indicating a biomass ratio of a compound (rubber). A meaning of this value is mentioned below.In 1 mole of carbon atoms (6.02×10 23 pieces), about 6.02×10 11 14 of C are present, which is about one bill of the number of normal carbon atoms. A half-life of 14 C is 5730 years and 14 C regularly decreases. Thus, in fossil fuels such as coal, petroleum, a natural gas and the like, which are considered to have passed 226,000 years or more since carbon dioxide was absorbed in the atmosphere of plants to fix it, all 14 C elements contained therein at the beginning of fixation decompose. Therefore, fossil fuels such as coal, petroleum, natural gas and the like do not contain a 14 C element in the present 21st century. Therefore, the chemical substances produced using these fossil fuels as raw materials also do not contain a 14 C element.On the other hand, 14 C is constantly generated by corrosive rays causing nuclear reactions in the atmosphere. Thus, decrease of 14 C due to radioactive decay and generation of 14 C due to nuclear reactions are compensated for, and the amount of 14 C in the atmospheric earth environment is constant. Therefore, the 14 C concentration of substances derived from biomass resources circulating in the present environment becomes a value of about 1×10 -12 mol % based on total C atoms as described above. Accordingly, by using a difference between these values, a biomass ratio in a particular compound can be calculated.This 14 C is generally measured as follows. Using an accelerator mass spectrometry based on a tandem accelerator, a 13 C concentration ( 13 C / 12 C) and a 14 C concentration ( 14 C / 12 C) are measured. In the measurements, a 14 C concentration in circulating carbon in the nature of 1950is used as reference standards for the 14 C concentration. As a specific reference material, an oxalic acid standard body provided by National Institute of Standards and Technology (NIST) is used. A specific radioactivity of carbon in this oxalic acid (radioactivity intensity of 14 C per gram of carbon) is sorted for each carbon isotope, 13 C is corrected to a constant value, and a value corrected for attenuation from 1950 until the measurement date is used as a standard 14 C concentration value (100%). A ratio of this value to an actually measured value for a sample becomes a pMC value.Thus, when a rubber is produced from a material derived from biomass to 100%, the 14 C concentration shows a value of about 110 pMC, currently it often does not reach 100 under a normal condition, although there are regional differences and the like. On the other hand, when this 14 C concentration is measured for a chemical substance derived from a fossil fuel such as petroleum and the like, it exhibits a value of about 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.Due to the above, in view of environmental protection, it is suitable to use a material such as a rubber having a high pMC value and the like, that is, a material such as a rubber having a high biomass ratio and the like, for a rubber composition.<Filler>The rubber composition according to the present embodiment comprises silica as a filler, and preferably comprises silica and carbon black.(Silica)Silica is not particularly limited, and those common in the tire industry may be used, such as dry process silica (anhydrous silica), wet process silica (hydrous silica), and the like. A raw material of silica is not particularly limited, and may be, for example, a mineral-derived raw material such as quartz and the like, a biomaterial-derived raw material such as rice hulls and the like (e.g., silica made from a biomass material such as rice hulls and the like), or silica recycled from a silica-containing product. Among them, hydrous silica prepared by a wet process is preferred for the reason that it has many silanol groups. This silica may be used alone, or two or more thereof may be used in combination.A nitrogen adsorption specific surface area (N 2 SA) of silica is preferably 100 m 2 / g or more, more preferably 120 m 2 / g or more, still more preferably 140 m 2 / g or more, still more preferably 160 m 2 / g or more, and particularly preferably 180 m 2 / g or more, from the viewpoint of securing reinforcing property and adhesion performance. Moreover, from the viewpoint of heat generation and processability, it is preferably 350 m 2 / g or less, more preferably 300 m 2 / g or less, and even more preferably 250 m 2 / g or less. In addition, the N 2 SA of silica is measured by the above-described measurement method.Silica from a biomass material can be obtained, for example, by burning rice hulls to obtain rice hull ash, extracting silicate from the rice hull ash using a sodium hydroxide solution, producing silica by reacting the silicate with sulfuric acid in the same manner as for a conventional wet silica and filtering, washing with water, drying and pulverizing precipitates of the silica.As the silica recycled from a product containing silica, silica recovered from an electronic component such as a semiconductor and the like, a tire, a product containing silica such as a desiccant, a filter material such as diatomaceous earth and the like, etc. can be used, for example. Moreover, a recovery method is not particularly limited, examples thereof include pyrolysis, electromagnetic wave decomposition, and the like. Among them, silica recovered from an electronic component such as a semiconductor, etc., or from a tire is preferable.When silica crystallizes, it is insoluble in water, and silica, which is a component thereof, cannot be used. By controlling a firing temperature and a firing time, crystallization of silica in rice hull ash can be suppressed (JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222, etc.). As an amorphous silica extracted from rice hulls, those commercially available from Wilmar, etc. can be used.An average primary particle size of silica is preferably 10 nm or more, more preferably 12 nm or more, and still more preferably 14 nm or more. Moreover, the average primary particle size is preferably 22 nm or smaller, more preferably 20 nm or smaller, and even more preferably 18 nm or smaller. In addition, the average primary particle size of silica is measured by the above-described measurement method.A content of silica based on 100 parts by mass of the rubber component is preferably more than 30 parts by mass, more preferably more than 40 parts by mass, still more preferably more than 50 parts by mass, still more preferably more than 60 parts by mass, still more preferably more than 70 parts by mass, still more preferably more than 80 parts by mass, and particularly preferably more than 90 parts by mass from the viewpoint of the effects of the present invention. Moreover, from the viewpoint of fuel efficiency, it is preferably less than 150 parts by mass, more preferably less than 130 parts by mass, even more preferably less than 120 parts by mass, and particularly preferably less than 110 parts by mass.(Carbon Black)Examples of carbon black include, but are not particularly limited to, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, and the like. A raw material of carbon black may be a biomass material such as lignin, a vegetable oil, and the like, or may be a pyrolysis oil obtained by pyrolyzing a used tire. Moreover, a method of producing carbon black may be one by combustion such as a furnace method and the like, one by hydrothermal carbonization (HTC), or one by pyrolysis of methane such as a thermal carbon black method and the like. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan K.K., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, NIPPON STEEL Carbon Co., Ltd., Columbia Chemical Corporation, etc. can be used. These carbon blacks may be used alone, or two or more of them may be used in combination.Moreover, besides the carbon black described above, from the viewpoint of ecobalance, carbon black from a biomass material such as lignin and the like or a recovered carbon black obtained by pyrolyzing and refining a product containing carbon black such as a tire and the like may be used as the carbon black.A "recovered soot" in the present specification refers to a soot obtained by pulverizing a product such as a used tire including soot and the like and burning the pulverized product, in which when the product is subjected to oxidative combustion by heating in the air using a thermal weight measurement method according to JIS K 6226-2:2003, a ratio of a mass of ash (ash content) that is a component that does not burn is 13 mass % or more. That is, a ratio of a mass (carbon amount) of a weight loss content due to the oxidative combustion of the recovered carbon black is 87 mass % or less. The recovered carbon black can be expressed by rCB.The recovered carbon black may be obtained from a pyrolysis process of a used pneumatic tire. EP3427975 A describes, for example, with reference to "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408 to 449 (2012), in particular pages 438, 440 and 442, that the recovered carbon black can be obtained by pyrolysis of an organic material at 550 to 800° C. with exclusion of oxygen or by vacuum pyrolysis at a relatively low temperature (

[0027] ). As mentioned in

[0004] of JP6856781 B (A comparison of surface morphology and chemistry of pyrolitic carbon blacks with commercial carbon blacks, Powder Technology 160 (2005), pp. 190-193), such carbon black obtained by the pyrolysis process normally lacks a functional group on its surface.The recovered carbon black may lack a functional group on its surface, or may be treated so that its surface comprises a functional group. The treatment carried out such that the surface of the recovered carbon black comprises a functional group can be implemented by a conventional method. In EP3173251 A, for example, carbon black comprising a hydroxyl and / or carboxyl group on its surface is obtained by treating carbon black obtained from a pyrolysis process with potassium permanganate under an acidic condition. Moreover, in JP6856781 B, carbon black whose surface is activated is obtained by treating carbon black obtained from a pyrolysis process with an amino acid compound including at least one thiol group or disulfide group. The recovered carbon black according to the present embodiment also includes carbon black whose surface has been treated to include a functional group.As the recovered carbon black, those commercially available from Street Green Carbon Pte Ltd., LDC Co., Ltd., etc. can be used.An average primary particle size of carbon black is preferably 12 nm or more, more preferably 15 nm or more, even more preferably 18 nm or more, and particularly preferably 20 nm or more. On the other hand, from the viewpoint of obtaining reinforcing properties, the average primary particle size is preferably 80 nm or smaller, more preferably 50 nm or smaller, and even more preferably 30 nm or smaller. In addition, the average primary particle size of carbon black is measured by the above-described measurement method.A nitrogen adsorption specific surface area (N 2 SA) of carbon black is preferably 200 m 2 / g or less, more preferably 180 m 2 / g or less, and even more preferably 150 m 2 / g or less, from the viewpoint of the effects of the present invention. Moreover, N 2 SA is preferably 100 m 2 / g or greater, more preferably 120 m 2 / g or greater, and even more preferably 130 m 2 / g or greater. In addition, the N 2 SA of soot is measured by the above-described measurement method.A content of carbon black when combined based on 100 parts by mass of the rubber component is preferably more than 1 part by mass, more preferably more than 3 parts by mass, still more preferably more than 5 parts by mass, still more preferably more than 9 parts by mass, and particularly preferably more than 15 parts by mass from the viewpoint of the effects of the present invention. Moreover, from the viewpoint of obtaining flexibility for alleviating stress, it is preferably less than 80 parts by mass, more preferably less than 60 parts by mass, even more preferably less than 40 parts by mass, even more preferably less than 30 parts by mass, even more preferably less than 25 parts by mass, and particularly preferably 20 parts by mass or less.(Other Fillers)The rubber composition may comprise fillers other than silica and carbon black. Other fillers are not particularly limited, and those conventionally and commonly used in the tire industry, such as aluminum hydroxide, calcium carbonate, clay, clay, talc and the like, may be compounded.<Silane Coupling Agent>Silica is preferably used in combination with a silane coupling agent. Examples of the silane coupling agent include, for example, sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide, and the like; mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like; vinyl-based silane coupling agents such as vinyltriethoxysilane, vinyltrimethoxysilane, and the like; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and the like; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and the like; Nitro-based silane coupling agents such as, but not limited to, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and the like; chloro-based silane coupling agents such as, but not limited to, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxy, and the like. Among them, sulfide-based silane coupling agents and / or mercapto-based silane coupling agents are preferably combined. As the silane coupling agent, for example, those commercially available from Evonik Industries AG, Momentive Performance Materials, etc. can be used. These silane coupling agents may be used alone, or two or more thereof may be used in combination.A content of a silane coupling agent based on 100 parts by mass of the rubber component (a total amount of plural silane coupling agents when used in combination) is preferably more than 3.0 parts by mass, more preferably more than 5.0 parts by mass, and even more preferably more than 6.0 parts by mass from the viewpoint of enhancing dispersibility of silica. Moreover, from the viewpoint of preventing deterioration of abrasion resistance, it is preferably less than 15 parts by mass, more preferably less than 10 parts by mass, and even more preferably less than 8.0 parts by mass.(Other Connecting Means)The rubber composition may suitably comprise, in addition to rubber components and fillers, binders conventionally and commonly used in the tire industry, for example, a plasticizer, processing aid, vulcanized rubber particle, wax, stearic acid, zinc oxide, antioxidant, vulcanizing agent, vulcanization accelerator and the like.<>A softening agent is a material that imparts plasticity to a rubber component, and has a concept including both a softening agent in a liquid state at 25° C. and a softening agent solid at 25° C. Examples of the plasticizer include resin, oil, a liquid rubber, an ester-based plasticizer, and the like. These softeners may be those derived from mineral resources such as petroleum, a natural gas and the like, or may be those derived from biomass. Moreover, a hydrocarbon component having a low molecular weight obtained by pyrolyzing and extracting a used tire or a product including various components can be used as a softening agent. The softening agent may be used alone, or two or more thereof may be used in combination.(Oil)Examples of oil include, for example, a mineral oil, a vegetable oil, an animal oil, and the like. Moreover, from the viewpoint of ecobalance, those obtained by purifying a waste oil after use in a rubber mixer or an engine or a waste feed oil used in a restaurant can be used. Oil may be used alone, or two or more thereof may be used in combination.In the present specification, a mineral oil refers to oil derived from mineral resources such as petroleum, a natural gas, and the like. Examples of the mineral oil include paraffinic oils (mineral oils), naphthenic oils, aromatic oils and the like. Specific examples of the mineral oil include, for example, mild extract solvate (MES), distilled aromatic extract (DAE), treated distilled aromatic extract (TDAE), treated residual aromatic extract (TBE), residual aromatic extract (RAE), and the like. Moreover, as an environmental measure, an oil having a low content of a polycyclic aromatic compound (PCA) may also be used. Examples of the oil having a low content of a PCA content include MES, TDAE, a heavy naphthenic oil, and the like.In the present specification, examples of the vegetable oil include, for example, a linseed oil, a rapeseed oil, a safflower oil, a soybean oil, a corn oil, a cottonseed oil, a rice oil, a tall oil, a sesame oil, a perilla oil, a castor oil, a tung oil, a pine oil, a pine tar oil, a sunflower oil, a coconut oil, a palm oil, a palm kernel oil, an olive oil, a camelial oil, a jojoba oil, a macadamia nut oil, an peanut oil, a grape kernel oil, a Japan wax, and the like. Further, examples of the vegetable oil also include a refined oil obtained by refining the above-described oil (an edible oil, etc.), a interesterified oil obtained by interesterifying the above-described oil, a hydrogenated oil obtained by hydrogenating the above-described oil, a thermally polymerized oil obtained by thermally polymerizing the above-described oil, an oxidized polymerized oil obtained by oxidizing the above-described oil, a used edible oil obtained by restoring what was used as an edible oil, etc., and the like. In addition, the vegetable oil may be liquid or solid at 25° C.The vegetable oil according to the present embodiment preferably comprises acylglycerol, and further preferably comprises triacylglycerol. In the present specification, acylglycerol also refers to a compound in which a hydroxy group of glycerol and a fatty acid are ester-bonded. Acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a multimer which is a trimer or higher. In addition, acylglycerol which is a dimer or higher can be obtained by thermal polymerization, oxidative polymerization, or the like. In addition, acylglycerol may be liquid or solid at 25°C.As a method of checking whether the rubber composition comprises acylglycerol, the check may be performed, but is not particularly limited to 1 H-NMR measurement. More specifically, a rubber composition comprising triacylglycerol is immersed in a heavy chloroform at 25° C. for 24 hours and removed to measure 1 H-NMR at room temperature, and when a signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals near 5.26 ppm, near 4.28 ppm, and near 4.15 ppm are observed, assuming that the signals are derived from hydrogen atoms bonded to carbon atoms adjacent to oxygen atoms of an ester group. Also, "close" in this paragraph is a range of ±0.10 ppm.The above-described fatty acid is not particularly limited, and may be an unsaturated fatty acid or a saturated fatty acid. Examples of the unsaturated fatty acid include a monounsaturated fatty acid such as oleic acid and the like and a polyunsaturated fatty acid such as linoleic acid, linolenic acid and the like. Moreover, examples of the saturated fatty acid include butyric acid, lauric acid and the like.Among them, as the fatty acid, a fatty acid having few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid is desired, and oleic acid is preferred. As a vegetable oil comprising such a fatty acid, for example, a vegetable oil comprising a saturated fatty acid or a monounsaturated fatty acid may be used, or a vegetable oil modified by transesterification or the like may be used. Moreover, in order to produce a vegetable oil comprising such a fatty acid, a plant can be improved by selective breeding, gene recombination or the like.As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo K.K., ENEOS Corporation, Olisoy, H&R Group, Hokoku Corporation, Fuji Kosan Co., Ltd., The Nisshin OilliO Group, Ltd., etc. can be used.Examples of the animal oil include a fish oil, a beef tallow, an oleyl alcohol derived therefrom which can be derived therefrom, and the like.A content of oil, when combined, based on 100 parts by mass of the rubber component is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more from the viewpoint of processability. Moreover, the content is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less. As described above, an "oil content" also includes an amount of oil contained in an oil-extended rubber.(Resin component)The rubber composition according to the present embodiment may include a resin component in combination. The resin component that can be used in the present embodiment is not particularly limited, and any resin that is usually used in the tire industry can be used, examples thereof include, for example, a C9-based resin, a C5-based resin, a C5 / C9-based resin, a dicyclopentadiene-based resin, an aromatic vinyl-based resin, a cumarone-based resin, an indene-based resin, a terpene-based resin, a rosin-based resin, a phenol-based resin, and the like. These resin components may be used alone, or two or more thereof may be used in combination. Each resin component may be used alone, or two or more thereof may be used in combination.<< Based on C9-C>>A "C9-based resin" refers to a resin obtained by polymerizing C9 fractions, and may be a polymer 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 referred to as a DCPD / C9 resin. Moreover, the C9-based resin may be one obtained by hydrogenating or modifying it. Examples of the C9fraction include, for example, a petroleum fraction having 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, dicyclopentadiene and the like. As the C9-based resin, for example, those commercially available from BASF, Zeon Corporation, ENEOS Corporation, etc. can be used.<< Based on C5-C>>A "C5-based resin" refers to a resin obtained by polymerizing C5 fractions, and may be one obtained by hydrogenating or modifying it. Examples of C5fractions other than dicyclopentadiene include, for example, a petroleum fraction having 4 to 5 carbon atoms such as cyclopentadiene, isoprene, piperylene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene and the like. As the C5-based resin, for example, those commercially available from STRUCTOL, Zeon Corporation, ENEOS Corporation, etc. can be used.<< Based on C5 / C9>A "C5 / C9 based resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be one obtained by hydrogenating or modifying it. As the C5 / C9 based petroleum resin, for example, those commercially available from Tosoh Corporation, Zibo Luhua Hongjin New Material Group Co., Ltd., etc. can be suitably used.<< Based dicyclopentadiene>>A "dicyclopentadiene-based resin" refers to a resin comprising cyclopentadiene (CPD) and / or dicyclopentadiene (DCPD) as a monomer component having the highest content, and may be one obtained by hydrogenating or modifying it. As the dicyclopentadiene-based resin, for example, a polymer obtained by polymerizing only dicyclopentadiene as a monomer, a copolymer obtained by copolymerizing dicyclopentadiene with the C9 fraction (DCPD / C9 resin), and the like are preferable. As the dicyclopentadiene-based resin, for example, those commercially available from Exxon Mobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. can be used.<< Based on aromatic vinyl>>An "aromatic vinyl-based resin" refers to a resin comprising an aromatic vinyl compound such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, and the like as a monomer component having the largest content, and may be one obtained by hydrogenating or modifying it. As the aromatic vinyl-based 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 it is economical, easy to process and excellent in heat generation. As the aromatic vinyl-based resin, for example, those commercially available from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used.<< Cumarone-Based Resin>>A "coumarone-based resin" refers to a resin comprising coumarone as a monomer component, and may be one obtained by hydrogenating or modifying it. As the coumarone-based resin, for example, a coumarone resin which is a polymer comprising only coumarone as a monomer component, a coumarone-indene resin which is a copolymer comprising coumarone and indene as monomer components, a coumarone-indene-styrene resin which is a copolymer comprising coumarone, indene and styrene as monomer components, and the like are preferable. As the coumarone-based resin, for example, those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. can be used.<<Indene-based resin>>An "indene-based resin" refers to a resin comprising indene as a monomer component, and may be one obtained by hydrogenating or modifying it. As the indene-based resin, for example, a coumarone-indene resin which is a copolymer comprising coumarone and indene as monomer components, a coumarone-indene-styrene resin which is a copolymer comprising coumarone, indene and styrene as monomer components, and the like are preferable. As the indene-based resin, for example, those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. can be used.<<-based rosin>>A "terpene-based resin" refers to a resin comprising a terpene compound such as α-pinene, β-pinene, limonene, dipentene, and the like as a monomer component, and may be one obtained by hydrogenating or modifying it. As the terpene-based resin, for example, a polyterpene resin that is a polymer including only one or more of the terpene compounds as monomer components, an aromatic modified terpene resin that is a copolymer including the terpene compound and an aromatic compound as monomer components, a terpene phenol resin that is a copolymer including the terpene compound and a phenol compound as monomer components, and the like are preferable. Examples of the aromatic compound used as a monomer component for the aromatic modified terpene resin include, for example, styrene, α-methylstyrene, vinyltoluene, divinyltoluene and the like. Examples of the phenol compound used as a monomer component for the terpene phenol resin include, for example, phenol, bisphenol A, cresol, xylenol, and the like. As the terpene-based resin, for example, those commercially available from Yasuhara Chemical Co., Ltd., Arakawa Chemical Industries, Ltd., Nippon Terpene Chemicals, Inc., etc. can be used.<< Based on rosin>>A "rosin-based resin" refers to a resin comprising a rosin acid compound such as abietic acid, neoabietic acid, palustric acid, isopimaric acid, and the like, and may be one obtained by hydrogenating or modifying it. Examples of the rosin-based resin include, for example, a rosin rosin and a rosin-modified resin obtained by modifying the rosin by hydrogenation, disproportionation, dimerization, esterification, etc., but are not particularly limited. As the rosin-based resin, for example, those commercially available from Harima Chemicals Group, Inc., Arakawa Chemical Industries, Ltd., IREC Co., Ltd., etc. can be used.<< Phenol Based Resin>>A "phenol-based resin" refers to a resin comprising a phenolic compound such as phenol, cresol, and the like as a monomer component, and may be one obtained by hydrogenating or modifying it. Examples of the phenol-based resin include, but are not particularly limited to, a phenol-formaldehyde resin, an alkylphenol-formaldehyde resin, an alkylphenol-acetylene resin, an oil-modified phenol-formaldehyde resin, a terpene-phenol resin, and the like. As the phenol-based resin, for example, those commercially available from Sumitomo Bakelite Co., Ltd., DIC Corporation, ASAHI YUKIZAI CORPORATION, etc. can be used.From the viewpoint of adhesion performance, a softening point of the resin component is preferably 60° C. or higher, more preferably 70° C. or higher, and even more preferably 80° C. or higher. Moreover, from the viewpoint of processability and improvement in dispersibility of a rubber component with a filler, it is preferably 150° C. or lower, more preferably 140° C. or lower, and even more preferably 130° C. or lower. In addition, the softening point of the resin component is measured by the above-described measurement method.A content of the resin component, when compounded, based on 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, and particularly preferably 18 parts by mass or more. Moreover, from the viewpoint of suppressing heat generation, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.(Liquid Rubber)A liquid rubber is not particularly limited as long as it is a polymer in a liquid state at 25° C., examples of which include, for example, a liquid butadiene rubber (a liquid BR), a liquid styrene-butadiene rubber (a liquid SBR), a liquid isoprene rubber (a liquid IR), a liquid styrene-isoprene rubber (a liquid SIR), a liquid farnesene rubber, and the like. The liquid rubber may be used alone, or two or more thereof may be used in combination.A content of the liquid rubber, when compounded, based on 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more. Moreover, the content of the liquid rubber is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 20 parts by mass or less.(Ester-based plasticizer)Examples of the ester-based plasticizer include, for example, dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), bis(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), trixylenyl phosphate (TXP), and the like. The ester-based plasticizer may be used alone, or two or more thereof may be used in combination.(Vulcanized rubber particle)A vulcanized rubber particle is a vulcanized rubber particle, and particularly, a rubber powder and the like specified in JIS K 6316:2017 can be used. From the viewpoint of environmental considerations and costs, a recycled rubber powder produced from a pulverized product of a used tire or the like is preferred. The vulcanized rubber particle may be used alone, or two or more thereof may be used in combination.The vulcanized rubber particle is not particularly limited, and may be an unmodified vulcanized rubber particle or a modified vulcanized rubber particle.As commercially available products of vulcanized rubbers, for example, products of Lehigh Technologies, Muraoka Rubber Recycling Co., Ltd., etc. can be used.(Wax)Wax is not particularly limited, and any of those usually used in the tire industry can be suitably used, examples of which include, for example, a mineral-based wax, a plant-derived wax, and the like. The mineral-based wax refers to wax derived from mineral resources such as oil, a natural gas, and the like. The wax derived from plants refers to wax derived from natural resources such as a plant and the like. Among them, the mineral-based wax is preferable. Examples of the vegetable-derived wax include, for example, rice wax, carnauba wax, candelilla wax, and the like. Examples of the mineral-based wax include, for example, paraffin wax, microcrystalline wax, specific selected waxes thereof, and the like. Among them, paraffin wax is preferred. Moreover, wax according to the present embodiment is not intended to include stearic acid. As the wax, for example, those commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt B.V., etc. can be used. Wax may be used alone, or two or more thereof may be used in combination.A content of wax, when combined, based on 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 parts by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of weather resistance of a rubber. Moreover, from the viewpoint of preventing whitening of a tire due to blooming, it is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass.Examples of an antioxidant include, but are not particularly limited to, a naphthylamine-based antioxidant such as phenyl-α-naphthylamine and the like; a diphenylamine-based antioxidant such as octylated diphenylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine and the like; p-Phenylenediamine-based antioxidant such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PP), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD), and the like; a quinoline-based antioxidant such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline, and the like; a monophenol-based antioxidant such as 2,6-di-t-butyl-4-methylphenol, a styrenated phenol and the like; bis-, tris- and polyphenol-based antioxidants such as tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane and the like. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferable, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferable. As commercially available products, for example, products manufactured by Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexsys, etc. can be used. The antioxidant may be used alone, or two or more thereof may be used in combination.A content of the antioxidant, when compounded, based on 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more from the viewpoint of ozone crack resistance of a rubber. Moreover, from the viewpoint of abrasion resistance and wet adhesion performance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.A content of stearic acid, when combined, based on 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more from the viewpoint of processability. Moreover, from the viewpoint of vulcanization rate, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.A content of zinc oxide, when combined, based on 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more from the viewpoint of processability. Moreover, from the viewpoint of abrasion resistance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.Sulfur is suitably used as a vulcanizing agent. As the sulfur, a powdery sulfur, an oil processing sulfur, a precipitated sulfur, a colloidal sulfur, an insoluble sulfur, a highly dispersible sulfur, and the like can be used.A content of sulfur when combined as a vulcanizing agent based on 100 parts by mass of the rubber component is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more from the viewpoint of ensuring a sufficient vulcanization reaction. Moreover, from the viewpoint of preventing deterioration, it is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.5 parts by mass or less. In addition, a content of a vulcanizing agent when an oil-containing sulfur is used as the vulcanizing agent is intended to be a total content of pure sulfur contained in the oil-containing sulfur.Examples of vulcanizing agents other than sulfur include, for example, an alkylphenol-sulfur chloride condensate, sodium hexamethylene-1,6-bisthiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and the like. As these vulcanizing agents other than sulfur, those commercially available from Taoka Chemical Co., Ltd., LANXESS, Flexsys, etc. can be used.Examples of the vulcanization accelerator include, for example, sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based or aldehyde-ammonia-based, imidazoline-based and xantate-based vulcanization accelerators, and the like. These vulcanization accelerators may be used alone, or two or more of them may be used in combination. Among them, one or more vulcanization accelerators selected from the group consisting of a sulfenamide-based, guanidine-based and thiazole-based vulcanization accelerator are preferred, and sulfenamide-based vulcanization accelerators are more preferred from the viewpoint of better obtaining desired effects.Examples of a sulfenamide-based vulcanization accelerator include, for example, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like. Among them, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS) and N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) are preferable.Examples of a guanidine-based vulcanization accelerator include, for example, 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatecholborate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, 1,3-di-o-cumenyl-2-propionylguanidine, and the like. Among them, 1,3-diphenylguanidine (DPG) is preferred.Examples of the thiazole-based vulcanization accelerator include, for example, 2-mercaptobenzothiazole, a cyclohexylamine salt of 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and the like. Among them, 2-mercaptobenzothiazole is preferred.A content of the vulcanization accelerator, when combined, based on 100 parts by mass of the rubber component is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2.0 parts by mass or more. Moreover, the content of the vulcanization accelerator based on 100 parts by mass of the rubber component is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, still more preferably 6.0 parts by mass or less, and particularly preferably 5.0 parts by mass or less. When the content of the vulcanization accelerator is within the above-described ranges, fracture toughness and elongation tend to be ensured.In the present specification, various materials including carbon atoms (for example, a rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method of obtaining compounds of the various materials from carbon dioxide, carbon dioxide may be directly converted, or methane obtained by a methanizing step of synthesizing methane from carbon dioxide may be converted.[Production]The rubber composition can be produced by a known method. It can be produced, for example, by kneading each of the above-described components using a rubber kneader such as an open roll, a closed type kneader (Bunbury mixer, kneader, etc.), and the like.The kneading step includes, for example, a base kneading step of kneading other compounds and additives than vulcanizing agents and vulcanization accelerators, and a final kneading step (F kneading) of adding vulcanizing agents and vulcanization accelerators to the kneaded product obtained by the base kneading step and kneading thereof. Further, the basic kneading step may be divided into a plurality of steps, if desired. In the case where the base kneading step is divided, the method may be (1) a method of kneading some of the joining agents and additives in a master batch in advance and then adding the remaining joining agents and additives to the obtained master batch and kneading them, (2) a method of kneading all of the joining agents and additives in the base kneading step at once and then rolling the kneaded product one or more times, or the like. In the above-described method (1), the number of masterbatches is not limited and may be two or more. Moreover, when the number of masterbatches is two or more, all the coupling agents and additives used in the base kneading step may be assigned to any of the masterbatches.A kneading condition is not particularly limited. Examples of kneading include, for example, a method of kneading at a discharge temperature of 150 to 170° C. for 3 to 10 minutes in the base kneading step, and a method of kneading at 70 to 110° C. for 1 to 5 minutes in the final kneading step. A vulcanization condition is not particularly limited. Examples of vulcanization include, for example, a method of vulcanization at 150 to 200° C. for 10 to 30 minutes.The tire comprising a tread portion composed of the rubber composition can be produced by a usual method. That is, the tire can be produced by extruding an unvulcanized rubber composition prepared by joining each of the above-described rubber components as needed for a rubber component into a mold of a tread portion, joining the unvulcanized tread portion thus obtained with other tire members on a tire molding machine, and molding it via a usual method of forming an unvulcanized tire, followed by heating and pressurizing the unvulcanized tire thus obtained in a vulcanizing machine. A vulcanization condition is not particularly limited. Examples of vulcanization include, for example, a method of vulcanization at 150 to 200° C. for 10 to 30 minutes.[Applications]In the present specification, the tire may be used for any applications regardless of whether it is a pneumatic tire or an airless tire, and may be used as a tire for a passenger car, a tire for a large passenger car, a tire for a large SUV, a racing tire, a motorcycle tire, a heavy load tire, or a run flat tire. Among them, it is preferably a tire for a passenger car. In addition, the tire for a passenger car is a tire provided that it is mounted on a car running on four wheels, and refers to one having a maximum load capacity of less than 1400 kg. Moreover, in the present specification, the tire may be used as a full year tire, a summer tire, or a winter tire such as a studless tire and the like.EXAMPLESExamples considered preferable for implementation (examples) are shown below, but the scope of the present invention is not limited to examples.Results are shown in Table 2, which were calculated based on evaluation methods described below, in consideration of a pneumatic tire including a tread portion produced using a rubber composition obtained by changing compounds shown in Table 1 using various chemicals shown below.NR: TSR20SBR: SLR6430 manufactured by The Dow Chemical Company (S-SBR, styrene content: 40 mass %, vinyl content: 20 mol %, Tg: -36° C., comprising 37.5 mass parts of extender oil content based on 100 mass parts of rubber component)BR: UBEPOL BR (registered trademark) 150B manufactured by Ube Industries, Ltd. (cis content: 97 mol %)Carbon black: Show Black N134 manufactured by Cabot Japan K.K. (N 2 SA: 148 m 2 / g, average primary particle size: 18 nm)Silica 1: Ultrasil (registered trademark) VN3 manufactured by Evonik Industries AG (N 2 SA: 175 m 2 / g, average primary particle size: 18 nm)Silica 2: Ultrasil (registered trademark) 9100GR manufactured by Evonik Industries AG (N 2 SA: 230 m 2 / g, average primary particle size: 15 nm)Coupling agent: Si266 manufactured by Evonik Industries AG (bis(3-triethoxysilylpropyl) disulfide)Oil: Diana Process NH-70S manufactured by Idemitsu Kosan Co., Ltd. (aromatic-based process oil)Resin component: SYLVATRAXX 4401 manufactured by Kraton Corporation (α-methylstyrene resin, Mw: 700, softening point: 85° C.)Zinc oxide: Zinc oxide No. 1, manufactured by Mitsui Mining & Melting Co., Ltd.Stearic acid: stearic acid "CAMELLIA" manufactured by NOF CORPORATIONWax: OZOCACE 0355 manufactured by Nippon Seiro Co., Ltd.Antioxidant 1: Nocrac 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine)Antioxidant 2: Nocrac RD manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (poly(2, 2, 4-trimethyl-1,2-dihydroquinoline))Sulfur: Seimi OT manufactured by Nippon Karyu Industry Co., Ltd. (10% oil-containing insoluble sulfur)Vulcanization Accelerator 1: Nocceler CZ manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-cyclohexyl-2-benzothiazolylsulfenamide (CBS))Vulcanization accelerator 2: Nocceler D, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (1,3-diphenylguanidine (DPG))(Examples and Comparative Examples)According to the compound formulas shown in Table 1, using a 1.7 liter closed Banbury mixer, all chemicals other than sulfur and vulcanization accelerators are kneaded for 5 minutes until a temperature reaches a discharge temperature at 170° C. to obtain a kneaded product. Next, using a twin-screw open roll, sulfur and vulcanization accelerator are added to the obtained kneaded product, and the mixture is kneaded for 4 minutes until the temperature reaches 105° C. to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is extruded into shapes of first and second layers of a tread portion with an extruder equipped with a die having a predetermined shape, and is joined to other tire members, thereby forming an unvulcanized tire, and the unvulcanized tire is press-vulcanized under a condition of 170° C. for 12 minutes to produce each test tire.< Of 30° C.-E*>A rubber test piece is cut out 20 mm in length×4 mm in width×1 mm in thickness from a first layer of a tread portion of each test strip such that a tire circumferential direction becomes a long side and a tire width direction becomes a thickness direction. For each rubber test piece, a complex elastic modulus (30° C-E*) having a dynamic strain of ±0.25%, a dynamic strain of 1.0% is measured under a condition of a temperature at 30° C., a frequency of 10 Hz, an initial strain of 5%, and a strain mode using EPLEXOR series manufactured by GaboSystemtechnik GmbH. 30° C.-ΔE* (0.25%-1.0%) is calculated from a difference between 30° C.-E* with the dynamic strain of ±0.25% and 30° C.-E* with the dynamic strain of 1.0%.< Of Rubber Hardness>A rubber hardness is measured by cutting a tread portion from a first layer of a tread portion such that a tire radial direction becomes a thickness direction to prepare a sample for measuring hardness, and pressing a type A durometer against the sample from the ground contact surface side at 23° C. according to JIS K 6253.< Stability during High-Speed Running>Each test tire is mounted on all wheels of a vehicle (Domestic FF, 2000 cc), and actual vehicle running of 10 rounds is performed on a test road with a dry asphalt road surface of about 120 km / h. 20 test drivers perform a sensory evaluation of vehicle sway during entry, turn, and exit while cornering at this time. The evaluation is performed using an integer value of 1 to 5 points (the smaller the swing, the higher the point) of 20 test drivers to calculate a total score. Then, a total score of the reference comparative example (comparative example 4) is converted into a reference value (100), and a score result for each test tire is given as an index proportional to the total score. The results show that the larger the numerical value, the better the steering stability during high-speed running. Table 1 Table 1Composite SetNR5050505050504545-50--3070SBR55555555555561, 961, 91105511011082,5-(Rubber solid content)(40)(40)(40)(40)(40)(40)(45)(45)(80)(40)(80)(80)(60)-BR1010101010101010201020201030Carbon black70452020202020701001007010010040Silica 14070100-100--40--40---Silica 2---100-100100-----25-Coupling agent3, 25, 68, 010, 08, 010, 010, 03, 2--3, 2-2, 5-Oil202530353035352052055258Resin component20202020202020202020202020-Zinc oxide3, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 02, 0Stearic acid stearic acid3, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 03, 02, 0Wax1, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 52,0Antioxidant 12, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 0Antioxidant 21, 01, 01, 01, 01, 01, 01, 01, 01, 01, 01, 01, 01, 01, 0Sulfur1, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 5Vulcanization Accelerator 12, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 02, 01, 5Vulcanization Accelerator 20, 81, 21, 61, 81, 61, 81, 80, 8--0, 8-0, 3-Physical Property30 °C-E* (0.25 %) (MPa)22,722,322, 024, 822, 024, 823,422, 222, 220,521, 622, 225, 1-30 °C-E* (1.0%) (MPa)16, 615, 815,016, 715,016, 716, 016, 317, 416,517, 317, 419, 1-30 °C - ΔE* (0.25% - 1.0%) (MPa)6, 16, 57, 08, 17, 08, 17, 45, 94, 84, 04, 34, 86, 0-Rubber Hardness65656565656565656565656565- Table 2Table 2Bonding of First LayerC1C2C3C4C5C6C7C8C6C6C9C10C11C12C13Second Layer ConnectionB. BB. BB. BB. BB. BB. BB. BB. BB. BB. BB. BB. BB. BB. BB. B30 °C-AE* (0.25% - 1.0%)6,16,57,08,17,08,17,45,98,18,14,84,04,34,86,0T (mm)13,013,013,013,10,010,010,013,010,010,013,013,013,010,015,030 °C - ΔE* (0.25% - 1.0%) / T0,470,500,540,620,700,810,740,450,810,810,370,310,330,480,40Total Volume of Side Groove / Volume of Tread Portion×100(%)3,53,53,53,53,53,53,53,53,51,03,53,53,53,53,5Maximum width of inclined groove (mm)12,012,012,012,012,012,012,012,010,010,012,012,012,012,012,0L 80 / L 00,50,50,50,50,50,50,50,51,01,00,50,50,50,50,5Steering stability index during high speed running10610811211611411811610511511196909410098<>Examples of embodiments of the present invention are shown below. [1] A pneumatic tire including a tread portion,wherein the tread portion is constructed from a rubber composition comprising a rubber component and silica,wherein a content of an isoprene-based rubber in the rubber component is greater than 40 mass %,wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, andwherein, when 30° C.-ΔE* (0.25%-1.0%), a difference between a complex elastic modulus at a dynamic strain of 0.25% and a complex elastic modulus at a dynamic strain of 1.0% measured under a condition of a temperature at 30° C., a frequency of 10 Hz, and an initial strain of 5% represents the rubber composition, and T in mm represents a thickness of the tread portion,30 °C - ΔE* (0.25% - 1.0%) 6.0 MPa or more, and30 °C - ΔE* (0.25% - 1.0%) / T is 0.45 or more.[2] The pneumatic tire of [1] above, wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 60 parts by mass. [3] The pneumatic tire of [1] or [2] above, wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 90 parts by mass. [4] The pneumatic tire of any one of [1] to [3] above, wherein 30° C.-ΔE* (0.25%-1.0%) is 7.0 MPa or more. [5] The pneumatic tire of any one of [1] to [4] above, wherein 30° C.-ΔE* (0.25%-1.0%) is 8.0 MPa or more. [6] The pneumatic tire of any one of [1] to [5] above, wherein 30° C.-ΔE* (0.25%-1.0%) / T is 0.60 or more. [7] The pneumatic tire of any one of [1] to [6] above, wherein 30° C.-ΔE* (0.25%-1.0%) / T is 0.75 or more. [8] The pneumatic tire of any one of [1] to [7], wherein the rubber composition comprises carbon black, and wherein a content of carbon black based on 100 parts by mass of the rubber component in the rubber composition is greater than 1 part by mass and less than 25 parts by mass, preferably greater than 3 parts by mass and 20 parts by mass or less, and more preferably greater than 5 parts by mass and 20 parts by mass or less. [9] The pneumatic tire of any one of [1] to [8] above, wherein a rubber hardness of the rubber composition is greater than 50 and less than 80, preferably greater than 55 and less than 75, and more preferably greater than 60 and less than 70.

[10] The pneumatic tire of any one of [1] to [9] above, wherein the tread portion includes one or more side grooves extending in a tire width direction, and wherein a total volume of the one or more side grooves is 2.0% or more and 5.0% or less, and preferably 2.5% or more and 5.0% or less of a volume of the tread portion.

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

[10] above, wherein the tread portion includes one or more circumferential grooves extending in a tire circumferential direction, and wherein in one of the one or more circumferential grooves, a ratio (L 80 / L 0) of a groove width L 80 at an 80% position of a groove depth of a deepest portion of the circumferential groove to a groove width L 0 at a ground contact surface of the tread portion is 0.3 or more and 0.7 or less.

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

[11] above, wherein the tread portion has a groove inclined in a tire circumferential direction or a tire width direction, and wherein a maximum width L of the groove inclined in the tire circumferential direction or the tire width direction is greater than 7.0 mm and less than 20.0 mm, preferably greater than 8.0 mm and less than 15.0 mm.

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

[12] above, wherein T is greater than 6.0 mm and less than 12.0 mm, and preferably greater than 8.0 mm and less than 12.0 mm.

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

[13] above, wherein the pneumatic tire is a tire for a passenger car.LIST OF REFERENCE CHARACTERS1 Circumferential groove 2 Land portion 3 First layer 4 Second layer 5 Inclined side groove 6 Tread ground contact surface 10 Tread portion 11 Shoulder land portion 12 Center land portion 21 Side groove 22 Shoulder sipe 23 Center sipe C Tire equator W Tire width direction Te Tread end T Total thickness of tread portion N Normal to Tread ground contact surface on Tire equator H Groove depth of deepest portion of circumferential groove L 0 Groove width of ground contact surface L 80 Groove width at 80% position of groove depth of deepest portionReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2014-80521 A

[0002] JP 2009-2594 A

[0095] EP 3427975 A

[0101] JP 6856781 B [0101, 0102]EP 3173251 A

[0102] Cited Non-Patent LiteratureASTM D 6866-10

[0084]

Claims

A pneumatic tire comprising a tread portion, wherein the tread portion is composed of a rubber composition comprising a rubber component and silica, wherein a content of an isoprene-based rubber in the rubber component is greater than 40 mass%, wherein a content of silica based on 100 mass parts of the rubber component in the rubber composition is greater than 30 mass parts, and wherein when 30°C-ΔE* (0.25%-1.0%), a difference between a complex elastic modulus at a dynamic strain of 0.25% and a complex elastic modulus at a dynamic strain of 1.0% measured under a condition of a temperature at 30°C, a frequency of 10 Hz, and an initial strain of 5% represents the rubber composition, and T in mm represents a thickness of the tread portion, 30° C.-ΔE* (0.25%-1.0%) 6.0 MPa or more, and 30° C.-ΔE* (0.25%-1.0%) / T is 0.45 or more.The pneumatic tire according to claim 1, wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 60 parts by mass.The pneumatic tire according to claim 1 or 2, wherein a content of silica based on 100 parts by mass of the rubber component in the rubber composition is greater than 90 parts by mass.The pneumatic tire according to any one of claims 1 to 3, wherein 30°C-ΔE* (0.25% - 1.0%) is 7.0 MPa or more.The pneumatic tire according to any one of claims 1 to 4, wherein 30°C-ΔE* (0.25% - 1.0%) is 8.0 MPa or more.The pneumatic tire according to any one of claims 1 to 5, wherein 30°C-ΔE* (0.25% - 1.0%) / T is 0.60 or more.The pneumatic tire according to any one of claims 1 to 6, wherein 30°C-ΔE* (0.25% - 1.0%) / T is 0.75 or more.The pneumatic tire according to any one of claims 1 to 7, wherein the rubber composition comprises carbon black, and wherein a content of carbon black based on 100 parts by mass of the rubber component in the rubber composition is greater than 1 part by mass and less than 25 parts by mass.The pneumatic tire according to any one of claims 1 to 8, wherein a rubber hardness of the rubber composition is greater than 50 and less than 80.The pneumatic tire according to any one of claims 1 to 9, wherein the tread portion has one or more side grooves extending in a tire width direction, and wherein a total volume of the one or more side grooves is 2.0% or more and 5.0% or less of a volume of the tread portion.The pneumatic tire according to any one of claims 1 to 10, wherein the tread portion has one or more circumferential grooves extending in a tire circumferential direction, and wherein in one of the one or more circumferential grooves, a ratio (L 80 / L 0) of a groove width L 80 at an 80% position of a groove depth of a deepest portion of the circumferential groove to a groove width L 0 at a ground contact surface of the tread portion is 0.3 or more and 0.7 or less.The pneumatic tire according to any one of claims 1 to 11, wherein the tread portion has a groove inclined in a tire circumferential direction or a tire width direction, and wherein a maximum width L of the groove inclined in the tire circumferential direction or the tire width direction is greater than 7.0 mm and less than 20.0 mm.The pneumatic tire of any one of claims 1 to 12, wherein T is greater than 6.0 mm and less than 12.0 mm.The pneumatic tire according to any one of claims 1 to 13, wherein the pneumatic tire is a tire for a passenger car.

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