tire

Abstract

To improve dry grip performance on a low-temperature road surface.SOLUTION: A tire having a tread portion, wherein a ratio (G / WL) of a tire weight G (kg) to a maximum load capacity WL (kg) of the tire is 0.0170 or less, a thickness T of the tread portion is 8. 0mm or less, the tread portion is made of a rubber composition containing a rubber ingredient, a filler, a plasticizing agent, and a cross-linking agent, a glass-transition temperature Tg of the rubber composition is - 30 °C. or more, and Tg * T is - 220 or more, A half-value width H of a peak within a range of - 20 °C. to - 70 °C. in a tan δ temperature distribution curve of the rubber composition is 60 °C. or more, and H / (G / WL) is 3600 or more.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] For tires mounted on automobiles, it is important to maintain the grip force between the tread and the road surface during driving, braking, and cornering of the automobile. Various methods for improving grip performance have been studied. For example, Patent Document 1 describes a pneumatic tire with tread rubber that uses fine zinc oxide particles to improve grip performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-285524 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to improve dry grip performance on low-temperature road surfaces. [Means for solving the problem]

[0005] The present invention provides A tire having a tread portion, Maximum tire load capacity W L Ratio of tire weight G (kg) to tire weight (G / W L ) is less than or equal to 0.0170, The thickness T of the tread portion is 8.0 mm or less, the tread portion is made of a rubber composition including a rubber component, a filler, a plasticizer, and a crosslinking agent, The rubber composition has a glass transition temperature Tg of −30° C. or higher, Tg × T is greater than or equal to -220, The half width H of a peak in the range of −20° C. to −70° C. in a tanδ temperature distribution curve of the rubber composition is 60° C. or more, H / (G / W L ) is 3600 or more, relating to tires. [Effects of the Invention]

[0006] According to the present invention, a tire is provided that improves dry grip performance on low-temperature road surfaces. [Brief explanation of the drawings]

[0007] [Figure 1] 2 is a diagram showing the tire section width Wt, tire section height Ht, and tire outer diameter Dt in a cross section of a tire perpendicular to the tire radial direction. FIG. [Figure 2] 1 is a cross-sectional view of a tread portion of a tire according to one embodiment of the present invention, the cross-section of which is perpendicular to the tire radial direction. [Figure 3] 1 is a schematic development view of a tread portion showing one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] The tire according to one embodiment of the present invention is a tire having a tread portion, and a maximum load capacity W L Ratio of tire weight G (kg) to tire weight (G / W L ) is 0.0170 or less, a thickness T of the tread portion is 8.0 mm or less, the tread portion is made of a rubber composition including a rubber component, a filler, a plasticizer, and a crosslinking agent, the glass transition temperature Tg of the rubber composition is -30°C or more, Tg × T is -220 or more, a half width H of a peak in a range of -20°C to -70°C in a tan δ temperature distribution curve of the rubber composition is 60°C or more, and H / (G / W L ) is 3600 or more, it is a tire.

[0009] The reason why the dry grip performance on a low-temperature road surface is improved in the tire of this embodiment is thought to be, for example, as follows, although it is not intended to be bound by theory.

[0010] First, (1) the maximum load capacity of the tire W L Ratio of tire weight G (kg) to tire weight (G / W L ) is 0.0170 or less, that is, a tire with a relatively small tire weight relative to its maximum load capacity. When such a tire is used, the vehicle weight, especially the unsprung weight, is lighter, so the input that the tire receives from the road surface is greater. Lighter tires improve the ratio of tire grip to vehicle weight, and it can be expected that the grip of the vehicle as a whole will improve relatively.

[0011] In addition, (2) because T is 8.0 mm or less, Tg is -30°C or more, and Tg × T is -220 or more, the glass transition temperature is high and the thickness of the tread portion is greater than a certain value. As a result, the rubber hardness increases as the temperature drops, and it can be expected that the force with which the tread surface scratches the road surface at low temperatures will increase.

[0012] (3) The half-width H of the peak in the range of -20°C to -70°C in the tan δ temperature distribution curve of the rubber composition constituting the tread portion is 60°C or more, which allows energy loss to occur over a wide frequency range during dry braking, thereby contributing to improved dry grip performance. Furthermore, (4) H / (G / W L ) is 3600 or higher, it becomes easier to convert energy received in various frequency ranges into thermal energy, so it is expected that input received from the road surface will be efficiently converted into thermal energy.

[0013] It is believed that the cooperation of the above (1) to (4) achieves the remarkable effect of providing a tire that improves dry grip performance on low-temperature road surfaces.

[0014] The ratio (0°C tanδ / T) of the loss tangent (0°C tanδ) of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz to T is preferably 0.12 or less.

[0015] In low-temperature conditions where heat generation is high, it is believed that dry grip performance can be further improved by making the tread rubber thicker than a certain level.

[0016] The product (0°C E* × T) of the complex modulus of elasticity of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz is preferably 70 or more.

[0017] By increasing the elastic modulus at low temperatures and making the tread rubber thicker than a certain level, it is possible to ensure hardness even at low temperatures, which is thought to further improve dry grip performance on low-temperature road surfaces.

[0018] The filler preferably contains carbon black with an average primary particle diameter of 18 nm or less. The inclusion of fine silica particles improves the ability to conform to micro-irregularities on the road surface, which is thought to further improve dry grip performance on low-temperature road surfaces.

[0019] Preferably, the filler contains carbon black and silica, and the mass ratio of the silica to the carbon black is greater than 1.0.

[0020] It is believed that by compounding more silica than a predetermined amount relative to the carbon black, the ability to follow the road surface improves, thereby improving the static friction coefficient and further improving dry grip performance.

[0021] When the acetone extractable amount of the rubber composition is defined as AE (mass %), AE / G is preferably less than 4.0.

[0022] By keeping the amount of acetone extracted relative to the tire weight below a certain level, hardening of the rubber at low temperatures can be suppressed, which is thought to further improve dry grip performance on low-temperature road surfaces.

[0023] It is preferable that the tread surface of the tread portion has one or more circumferential grooves extending continuously in the tire circumferential direction and two or more land portions defined by the circumferential grooves and the ground contact edge, the land portions having lateral grooves extending in the tire width direction, and the lateral grooves having portions where the groove width in a cross section perpendicular to the tire radial direction is wider than the groove width on the tread surface.

[0024] Even when the tread wears, the groove area of ​​the lateral grooves increases, which improves drainage performance and is thought to further improve grip performance.

[0025] It is preferable that the tread surface of the tread portion has one or more circumferential grooves extending continuously in the circumferential direction of the tire and two or more land portions defined by the circumferential grooves and the ground contact edge, and the ratio of the area of ​​the circumferential grooves to the area of ​​the tread ground contact surface is more than 19% and less than 32%.

[0026] It is believed that by setting the groove area of ​​the circumferential groove to a predetermined value or more, drainage performance can be ensured and grip performance can be further improved.

[0027] The product (30°C tanδ × 0°C tanδ) of the loss tangent of the rubber composition measured under conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of 1%, and a frequency of 10 Hz (30°C tanδ) and the loss tangent of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz is preferably greater than 0.11.

[0028] It is believed that by setting tan δ in the low temperature range to the normal temperature range to a predetermined value or more, the grip performance in the temperature range can be further improved.

[0029] The content of butadiene rubber in the rubber component is preferably more than 0% by mass and not more than 60% by mass. By setting the content of butadiene rubber within the specified range, it is believed that grip performance can be further improved.

[0030] The rubber composition preferably contains a mercapto-based silane coupling agent, which is believed to further improve low-temperature grip performance.

[0031] When the loss tangent of the rubber composition measured under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is 30°C tanδ, and the loss tangent of the rubber composition measured under the conditions of a temperature of 60°C, an initial strain of 10%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is 60°C tanδ, (30°C tanδ - 60°C tanδ) / T is 8.75 × 10 -3 It is preferable that (30°C tan δ - 60°C tan δ) / T is less than 8.75 × 10 -3 It is believed that the fuel efficiency of the tire is improved by keeping the above value below.

[0032] [Definition] The "tread portion" is the portion that forms the contact surface of the tire, and in the case where the tire has components that form the tire skeleton from steel or textile materials, such as a belt layer, a belt reinforcing layer, and a carcass layer, in the radial cross section of the tire, the "tread portion" is the component that is radially outward of these components.

[0033] "Normal condition" refers to a condition in which the tire is mounted on a normal rim and filled with air at normal internal pressure, with no load applied.

[0034] Unless otherwise specified, the "dimensions of each part of the tire" are values ​​that appear on the outer surface of the tire when in a normal state, while those that appear inside the tire or on a cut surface of the tire are values ​​that are specified when the tire is cut along a plane that includes the tire rotation axis and the cut tire piece is maintained at the rim width of a normal rim.

[0035] "Genuine rim" refers to the rim specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," for ETRTO (The European Tyre and Rim Technical Organization), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." JATMA, ETRTO, and TRA are referenced in that order, and if an applicable size is available at the time of reference, that standard is followed. In the case of a tire not specified in the above standards, it refers to the narrowest rim among the smallest diameter rims that can be mounted on the tire and can maintain internal pressure (i.e., no air leaks from between the rim and tire).

[0036] "Normal internal pressure" refers to the air pressure specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA, it refers to the "maximum air pressure," for ETRTO, it refers to "INFLATION PRESSURE," and for TRA, it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims, refer to JATMA, ETRTO, and TRA in that order, and follow that standard if there is an applicable size at the time of reference. In the case of tires not specified in the above standards, it refers to the normal internal pressure (250kPa or more) of another tire size (specified in the standard) that is specified using the regular rim as the standard rim, and if there are multiple normal internal pressures of 250kPa or more listed, it refers to the smallest value among them.

[0037] "Normal load (kg)" is the load specified for each tire in the standard system including the standard on which the tire is based, for example, "Maximum Load Capacity" for JATMA, "Load Capacity" for ETRTO, and the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA. As with normal rims and normal internal pressures, JATMA, ETRTO, and TRA should be referenced in that order, and if there is an applicable size at the time of reference, that standard should be followed. For tires not specified in the above standards, the maximum load capacity W calculated separately should be used. L is the normal load.

[0038] "Maximum load capacity W L (kg)" is calculated using the following formula: "V" is the virtual volume of the tire (mm 3 ), "Dt" is the outer diameter (mm) of the tire in its normal state, "Ht" is the tire's cross-sectional height (mm) in the tire's radial direction in a cross section of the tire taken along a plane including the tire's rotation axis, and "Wt" is the tire's cross-sectional width (mm) in its normal state. Ht can be calculated by (Dt-R) / 2, where R is the tire rim diameter. Wt is the value obtained by excluding any patterns or letters on the tire sidewall. Note that maximum load capacity is synonymous with the normal load mentioned above.

[0039]

number

[0040] "Tire weight G (kg)" refers to the weight of the tire itself, excluding the weight of the rim. On the other hand, if the tire has components such as sponge or sealant, or sensor components, the weight includes these components.

[0041] The "tread portion" refers to a component that includes the portion that forms the tire's contact surface, and in a cross section of the tire taken along a plane including the tire rotation axis, if the tire is equipped with components that form the tire skeleton using steel or textile materials, such as a belt layer, a belt reinforcing layer, and a carcass layer, the "tread portion" refers to a component that is located radially outward of these components.

[0042] The "tread contact surface" refers to the surface where the tread comes into contact with the ground when a tire is mounted on a standard rim, inflated to the standard internal pressure, placed vertically on a flat surface, and subjected to a standard load. This can be obtained, for example, by applying ink to the tread surface and pressing it against cardboard. The area of ​​the tread contact surface is calculated by rotating the tire 72° circumferentially, transferring the image at five locations, and obtaining five contact profiles, and then averaging the results. The tread contact surface is shown schematically in Figure 2. The enclosed area in the figure is the tread contact surface.

[0043] The "land portion" refers to the portion of the tread defined by the circumferential grooves and the contact edge, which is the portion of the tire that comes into contact with the ground when the tire is pressed against the ground. In other words, it is the portion of the tread that constitutes the effective contact area.

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

[0045] The term "circumferential groove" refers to a groove that extends continuously in the circumferential direction of the tire. The circumferential groove may extend linearly along the circumferential direction, or may extend in a wavy, sinusoidal, or zigzag pattern along the circumferential direction.

[0046] "Tread thickness T (mm)" is the thickness of the entire tread measured along a normal to the tread contact patch on the tire equatorial plane in a cross section perpendicular to the tire radial direction. In the case where the tire has grooves on the equatorial plane, the thickness is measured along a normal to the tread contact patch on the center in the tire width direction of the land portions present on both sides of the groove in the tire width direction, the land portions having a center in the tire width direction closest to the tire equatorial plane. In the case where the tread is formed from multiple rubber layers, the sum of the thicknesses of the rubber layers constituting each layer is the "tread thickness T."

[0047] The "glass transition temperature (Tg) of a rubber composition" is the temperature (tan δ peak temperature) corresponding to the maximum value in the range of -60°C to 40°C in the temperature distribution curve obtained by measuring the tan δ temperature distribution curve using a dynamic viscoelasticity measuring device (e.g., an Iplexer series manufactured by GABO) under conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / min. In the measurement in the range of -60 to 40°C, if the tan δ value continues to gradually increase or decrease with increasing temperature, the glass transition temperature of the rubber composition is taken to be 40°C or -60°C, respectively. In addition, if there are two or more points showing maximum values ​​in the range of -60°C to 40°C, the lowest temperature point is taken to be the glass transition temperature.

[0048] The "half-value width H of the peak within the range of -20 ° C to -70 ° C in the tan δ temperature distribution curve of the rubber composition (half-value width of the tan δ peak)" can be determined from the tan δ temperature distribution curve measured by the method disclosed in JP 2021-54377 A. That is, for each vulcanized test piece, a dynamic viscoelasticity measuring device (e.g., an Iplexer series manufactured by GABO) is used to measure the tan δ temperature distribution curve in the temperature range from -20 ° C to -70 ° C under conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2 ° C / min, and a temperature dispersion curve is obtained with temperature on the X axis and tan δ on the Y axis. Let A be the tan δ at the peak position of the obtained temperature distribution curve, B be the intersection of the X-axis with a line that passes through A and is parallel to the Y-axis, C be the midpoint of line segment AB, D be the line that passes through C and is parallel to the X-axis, and E and F be the two intersections of D and the temperature distribution curve. This is defined as the absolute value of the difference in temperature between E and F.

[0049] "0°C tan δ" is the loss tangent measured using a dynamic viscoelasticity measuring device (e.g., the Iplexer series manufactured by GABO) under conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and an extension mode. The sample for measuring 0°C tan δ is a vulcanized rubber composition having a length of 20 mm, a width of 4 mm, and a thickness of 1 mm. When cutting out a sample from a tire, the sample is cut out from the tread portion so that the long side is in the tire circumferential direction and the thickness direction is in the tire radial direction.

[0050] "30°C tanδ" is the loss tangent measured using a dynamic viscoelasticity measuring device (e.g., the Iplexer series manufactured by GABO) under the conditions of a temperature of 30°C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and an extension mode. The sample for this measurement is prepared in the same manner as for 0°C tanδ.

[0051] "60°C tanδ" is the loss tangent measured using a dynamic viscoelasticity measuring device (for example, the Iplexer series manufactured by GABO) under the conditions of a temperature of 60°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±1%, and an extension mode. The sample for this measurement is prepared in the same manner as for 0°C tanδ.

[0052] "0°C E*" is the complex modulus measured using a dynamic viscoelasticity measuring device (e.g., the Iplexer series manufactured by GABO) under the conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and an extension mode. The sample for this measurement is prepared in the same manner as for 0°C tan δ.

[0053] "Acetone extractables (AE)" is a value calculated by immersing each vulcanized rubber test piece in acetone for 72 hours in accordance with JIS K 6229 to extract the soluble components, measuring the mass of each test piece before and after extraction, and then using the following formula: Acetone extractable amount (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0054] "Styrene content" is measured by pyrolysis gas chromatography and NMR measurement ( 1 H-NMR and 13 The amount of components such as "styrene content" is calculated by C-NMR. Unlike physical property values ​​such as complex modulus (E*), the amount of components such as "styrene content" has a true value that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible. In this specification, "pyrolysis gas chromatography" refers to a method in which a sample is heated in a pyrolysis device, the individual components contained in the gas phase components generated by this heating are separated using a separation column, and each isolated component is analyzed.

[0055] "Vinyl content (amount of 1,2-bonded butadiene units)" can be measured by pyrolysis gas chromatography or NMR measurement ( 1 H-NMR and 13 It is calculated using C-NMR. As with the "styrene content," there is a true value for the "vinyl content" that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0056] "Cis content (cis-1,4-bonded butadiene unit amount)" is measured by infrared absorption spectroscopy or NMR measurement ( 1 H-NMR and 13This is a value measured by C-NMR and is applied to rubber components that have repeating units derived from butadiene, such as BR. As with the "styrene content," the "cis content" also has a true value that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0057] The "weight average molecular weight (Mw)" can be determined by converting the measured value into standard polystyrene equivalents using gel permeation chromatography (GPC) (for example, a GPC-8000 series manufactured by Tosoh Corporation, a differential refractometer as the detector, and a TSKgel SuperMultipore HZ-M column manufactured by Tosoh Corporation). This applies to, for example, SBR, BR, plasticizers, etc.

[0058] The "nitrogen adsorption specific surface area (N2SA) of carbon black" is measured in accordance with JIS K 6217-2:2017.

[0059] The "nitrogen adsorption specific surface area (N2SA) of silica" is measured by the BET method in accordance with ASTM D3037-93.

[0060] The "average primary particle size" is a value obtained by photographing particles with a transmission or scanning electron microscope and arithmetically averaging the particle sizes of 400 particles. If the particle shape is spherical, the particle size is the diameter of the sphere, and if the particle shape is non-spherical, the particle size is calculated from the microscope image as the circle-equivalent diameter (positive square root of {4 × (particle area) / π}).

[0061] "Plasticizer" is a material that imparts plasticity to rubber components and is a component that is extracted from rubber compositions using acetone. Plasticizers include those that are liquid (fluid) at 25°C and those that are solid at 25°C. However, this does not include waxes and stearic acid, which are commonly used in the tire industry.

[0062] The "softening point of the resin component" is the softening point specified in JIS K 6220-1:2015 7.7 measured using a ring and ball softening point tester, and is the temperature at which the ball drops.

[0063] [tire] A tire according to one embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and the tire of the present invention is not limited to the following embodiment.

[0064] (Tire weight G) From the viewpoint of the effects of the present invention, the tire weight G of the tire according to this embodiment is preferably 15.0 kg or less, more preferably 12.0 kg or less, even more preferably 10.0 kg or less, even more preferably 8.0 kg or less, particularly preferably 7.5 kg or less, and most preferably 6.5 kg or less. The lower limit of the tire weight G is not particularly limited, but may be, for example, 3.5 kg or more, 5.5 kg or more, etc. The tire weight G can be varied in a conventional manner; that is, it can be increased by increasing the specific gravity of the tire or the thickness of each component of the tire, or conversely, it can be decreased by increasing the specific gravity of the tire or the thickness of each component of the tire.

[0065] (G / W L ) The tire according to this embodiment has a maximum load capacity W L Ratio of tire weight G (kg) to tire weight (G / W L ) is 0.0170 or less. L The value of is preferably 0.0150 or less, more preferably 0.0140 or less, even more preferably 0.0135 or less, and particularly preferably 0.0130 or less. There is no particular restriction on the lower limit, but it can be, for example, 0.0050 or more.

[0066] In addition, the maximum load capacity W L can be increased by increasing the virtual volume V of the space occupied by the tire, or conversely, can be decreased.

[0067] (tread area) The tire according to the present embodiment has a tread portion, which is made of a rubber composition containing a rubber component, a filler, a plasticizer, and a crosslinking agent.

[0068] The glass transition temperature Tg of the rubber composition according to this embodiment is −30° C. or higher, preferably −29° C. or higher, more preferably −28° C. or higher, even more preferably −27° C. or higher, and particularly preferably −26° C. or higher. The glass transition temperature Tg of the rubber composition is preferably above 0° C., more preferably −10° C. or lower, even more preferably −12° C. or lower, even more preferably −15° C. or lower, and particularly preferably −18° C. or lower. The glass transition temperature Tg of the rubber composition can be adjusted appropriately by the types and amounts of the rubber components, fillers, plasticizers, etc., which will be described later.

[0069] The half width H of the peak in the range of −20° C. to −70° C. in the tan δ temperature distribution curve of the rubber composition according to this embodiment is 60° C. or more, and from the viewpoint of the effects of the present invention, it is preferably 62.5° C. or more, more preferably 65.0° C. or more, even more preferably 67.0° C. or more, still more preferably 68.0° C. or more, and particularly preferably 70.0° C. or more. Furthermore, from the viewpoint of ensuring a certain level of grip performance at low to high temperatures, H is preferably 85.0° C. or less, more preferably 82.0° C. or less, and even more preferably 80.0° C. or less.

[0070] To prepare a rubber composition with a half-width H of 60°C or more, various methods can be used to change tan δ. For example, H can be broadened by blending a resin component that is highly compatible with the rubber component or by increasing the filler content.

[0071] (H / (G / W L )) The tire according to this embodiment has a H / (G / W L ) is 3600 or more. L) is preferably 4000 or more, more preferably 4500 or more, even more preferably 5000 or more, even more preferably 5500 or more, even more preferably 6000 or more, even more preferably 6500 or more, even more preferably 7000 or more, even more preferably 7500 or more, particularly preferably 8000 or more, and most preferably 8500 or more. There is no particular restriction on the upper limit, but it can be, for example, 12000 or less, 11000 or less, 10000 or less, etc.

[0072] The rubber composition according to the present embodiment has a loss tangent (0°C tanδ) measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz, preferably exceeding 0.45, more preferably exceeding 0.50, even more preferably exceeding 0.55, and particularly preferably exceeding 0.60. The lower limit of 0°C tanδ is preferably less than 0.80, more preferably less than 0.75, even more preferably less than 0.72, and particularly preferably less than 0.70.

[0073] The rubber composition according to the present embodiment has a complex modulus (0°C E*) measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz, of preferably more than 15 MPa, more preferably more than 18 MPa, even more preferably more than 20 MPa, and particularly preferably more than 21 MPa. The lower limit of 0°C E* is preferably less than 50 MPa, more preferably less than 40 MPa, even more preferably less than 30 MPa, and particularly preferably less than 25 MPa.

[0074] The rubber composition according to the present embodiment has a loss tangent (30°C tanδ) measured under conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1.0%, and a frequency of 10 Hz, and the loss tangent (30°C tanδ) is preferably greater than 0.20, more preferably greater than 0.25, even more preferably greater than 0.26, and particularly preferably greater than 0.27. The lower limit of the 30°C tanδ is preferably less than 0.50, more preferably less than 0.45, even more preferably less than 0.40, and particularly preferably less than 0.35.

[0075] The rubber composition according to the present embodiment has a loss tangent (60°C tanδ) measured under conditions of a temperature of 60°C, an initial strain of 10%, a dynamic strain of ±1.0%, and a frequency of 10 Hz, and the loss tangent (60°C tanδ) is preferably greater than 0.15, more preferably greater than 0.18, even more preferably greater than 0.20, and particularly preferably greater than 0.22. The lower limit of the 60°C tanδ is preferably less than 0.50, more preferably less than 0.45, even more preferably less than 0.40, and particularly preferably less than 0.35.

[0076] The values ​​of 0°C tan δ, 0°C E*, 30°C tan δ, and 60°C tan δ can be adjusted by methods commonly used in the tire industry. For example, the value of 30°C tan δ can be reduced by reducing the filler content, and conversely, the value of 30°C tan δ can be increased by increasing the filler content. Therefore, those skilled in the art can appropriately adjust the value of 30°C tan δ depending on the target 30°C tan δ.

[0077] The 30°C tan δ x 0°C tan δ of the rubber composition according to this embodiment is preferably greater than 0.10, more preferably greater than 0.11, even more preferably 0.12 or greater, still more preferably 0.13 or greater, and particularly preferably 0.15 or greater.

[0078] The acetone extractable amount AE of the rubber composition according to the present embodiment is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0079] The acetone extractables AE can be appropriately adjusted by changing the types and amounts of the rubber components, fillers, plasticizers, etc., which are blended into the rubber composition, as described below. For example, the acetone extractables AE can be increased by increasing the oil content.

[0080] (AE / G) In the tire according to the present embodiment, the ratio of AE (mass%) to G (kg) (AE / G) is preferably less than 4.0. The value of AE / G is more preferably less than 3.8, and even more preferably less than 3.6. The lower limit of the value of AE / G is not particularly limited, but is usually more than 2.8.

[0081] 2 is a cross-sectional view of the tire tread taken along a plane perpendicular to the tire radial direction. In FIG. 2, the vertical direction is the tire radial direction, the horizontal direction is the tire width direction, and the direction perpendicular to the paper surface is the tire circumferential direction.

[0082] As shown in Figure 2, the tread portion may have a first layer 6 whose outer surface constitutes the tread surface 3, and a second layer 7 adjacent to the radially inward side of the first layer 6. The tread portion of the tire of this embodiment has at least one rubber layer, and may have two or more rubber layers. When the tread portion has two or more rubber layers, it is sufficient that at least one of the two or more rubber layers satisfy the physical properties such as Tg and half width H, but it is preferable that the rubber composition constituting the first layer 6 satisfy these properties.

[0083] In Fig. 2, the double arrow t1 indicates the thickness of the first layer 6, and the double arrow t2 indicates the thickness of the second layer 7. In Fig. 1, the midpoint of the land portion 2 in the tire width direction is indicated by the symbol P. The line indicated by the symbol N passes through point P and is a line (normal line) perpendicular to the tangent plane at point P.

[0084] (Tread thickness T) The tread thickness T of the tire of this embodiment is 8.0 mm or less, preferably 7.8 mm or less, more preferably 7.5 mm or less, even more preferably 7.2 mm or less, still more preferably 7.0 mm or less, and particularly preferably 6.8 mm or less. From the viewpoint of ride comfort performance, T is preferably 4.0 mm or more, more preferably 5.0 mm or more, and even more preferably 5.5 mm or more.

[0085] When the tread portion has two or more layers, the thickness t1 of the first layer 6 is not particularly limited, but from the viewpoint of ride comfort performance, it is preferably 3.5 mm or more, more preferably 4.0 mm or more, and even more preferably 4.5 mm or more.

[0086] When the tread portion has two or more layers, the thickness t2 of the second layer 7 is not particularly limited, but is preferably 0.5 mm or more, more preferably 0.6 mm or more, and even more preferably 0.7 mm or more. The thickness t2 of the second layer 7 is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.1 mm or less.

[0087] The ratio (0°C tan δ / T) of the loss tangent (0°C tan δ) of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz to T is preferably 0.20 or less, more preferably 0.15 or less, even more preferably 0.12 or less, still more preferably 0.10 or less, and particularly preferably 0.08 or less. The lower limit of 0°C tan δ / T is not particularly limited, but can be, for example, 1.0 or more, 2.0 or more, etc.

[0088] The product (0°C E* × T) of the complex modulus of elasticity of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz, and T is preferably 70 or more, more preferably 90 or more, and even more preferably 100 or more. The upper limit of 0°C E* × T is not particularly limited, but can be, for example, 200 or less, 180 or less, etc.

[0089] The rubber composition according to the present embodiment has a value of (30°C tan δ-60°C tan δ) / T of preferably 9.00×10 -3 less than 8.75 × 10 -3 less than 8.50 × 10 -3 The lower limit of (30°C tan δ - 60°C tan δ) / T is not particularly limited, but may be, for example, 0.47 × 10 -3 Super, 0.50×10 -3 It can be super-idempotent.

[0090] (Circumferential groove, land area) The tread surface of the tread portion preferably has one or more circumferential grooves extending continuously in the tire circumferential direction, and two or more land portions defined by the circumferential grooves and the ground contact edges.

[0091] The circumferential grooves may extend linearly or zigzag. The number of circumferential grooves may be one or more. However, two or more circumferential grooves divide the land portion into at least one pair of shoulder land portions and a center land portion sandwiched between them. Three or more circumferential grooves further divide the center land portion into a land portion that faces the inside of the vehicle when mounted on the vehicle and a land portion that faces the outside of the vehicle. This allows the tread patterns of the respective land portions to be different, which is preferable because it increases the degree of freedom in designing the tread pattern. The number of circumferential grooves may be four or more, or five or more.

[0092] The ratio of the area of ​​the circumferential grooves to the area of ​​the tread contact patch is preferably more than 19% and less than 32%, more preferably 20% or more, and even more preferably 22% or more, while the ratio is preferably 30% or less, more preferably 28% or less.

[0093] When there are three or more circumferential grooves, the circumferential grooves consist of a pair of outermost circumferential grooves on the outermost side in the tire width direction and a center circumferential groove located inward in the tire width direction from the pair of outermost circumferential grooves. For example, FIG. 3 shows three circumferential grooves: a center circumferential groove 11 and outermost circumferential grooves 12 and 13. In this case, the land portions are divided into shoulder land portions located outward in the tire width direction from the outermost circumferential grooves and a center land portion located inward in the tire width direction from the outermost circumferential grooves. For example, FIG. 3 shows center land portions 21 and 22 and shoulder land portions 23 and 24. It is preferable that the center circumferential groove has a wider groove width than the outermost circumferential groove. This is because it improves drainage performance in the tire center and contributes to improved grip performance. For example, in FIG. 3, the groove width of the center circumferential groove 11 is wider than the groove widths of the outermost circumferential grooves 12 and 13.

[0094] (Yokomizo) The land portions preferably have lateral grooves extending in the tire width direction. For example, in Fig. 3, a plurality of lateral grooves 31, 32, 33, 34, 35, 36, 37, 38 are shown in the center land portions 21, 22 and the shoulder land portions 23, 24.

[0095] The lateral grooves preferably have a portion (widened portion) where the groove width is wider than the groove width at the tread surface in a cross section perpendicular to the tire radial direction. The shape of the widened portion is not particularly limited as long as it improves drainage performance in accordance with tire wear, thereby improving grip performance. For example, Figure 3 shows widened lateral grooves 31, 32, 33, and 34, which are lateral grooves with widened portions. The widened portion of such widened lateral grooves has a groove width that expands uniformly from the tread surface to the groove bottom along the tire radial direction, i.e., the groove width is widest at the groove bottom. Therefore, the more the tire wears, the better the drainage performance becomes.

[0096] [Rubber composition] The rubber composition constituting the tread portion of the tire according to the present embodiment (hereinafter referred to as the rubber composition according to the present embodiment) contains a rubber component, a filler, a plasticizer, and a crosslinking agent. The rubber composition according to the present embodiment will be described below.

[0097] The rubber composition according to the present embodiment preferably contains a diene rubber as a rubber component. Any diene rubber commonly used in the tire industry can be suitably used. Specific examples include isoprene (IR) rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). These diene rubbers may be used alone or in combination of two or more. The rubber composition according to the present embodiment preferably contains one or more rubber components selected from the group consisting of SBR, BR, and isoprene-based rubber, and more preferably contains two or more rubber components. Furthermore, the rubber composition according to the present embodiment more preferably contains SBR, and particularly preferably contains SBR and BR. These diene rubbers may be used alone or in combination of two or more.

[0098] <Rubber component> (SBR) The SBR is not particularly limited, and examples thereof include solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs thereof (modified S-SBR, modified E-SBR). Modified SBRs include SBRs whose terminals and / or main chains have been modified with compounds (modifiers) having the functional groups listed below; modified SBRs (condensates, those having a branched structure, etc.) coupled with tin, silicon compounds, etc. Furthermore, hydrogenated products of these SBRs (hydrogenated SBRs) can also be used. These SBRs may be used alone or in combination of two or more.

[0099] The functional group of the modifying agent is preferably a functional group containing at least one element selected from the group consisting of silicon, nitrogen, and oxygen. Examples of such functional groups include amino, amido, silyl, alkoxysilyl, isocyanate, imino, imidazole, urea, ether, carbonyl, oxycarbonyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imido, hydrazo, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy (preferably an alkoxy group having 1 to 6 carbon atoms), hydroxyl, oxy, and epoxy groups. Of these, amino and / or alkoxysilyl groups are preferred. The amino group is preferably an amino group substituted with one or two alkyl groups having 1 to 6 carbon atoms. Specific examples of the alkoxysilyl include trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethylmethoxysilyl, and dimethylethoxysilyl.

[0100] As the SBR, either oil-extended or non-oil-extended SBR can be used. SBR that can be used in this embodiment includes those commercially available from JSR Corporation, Sumitomo Chemical Co., Ltd., UBE Corporation, Asahi Kasei Corporation, ZS Elastomers Co., Ltd., ARLANXEO, etc.

[0101] The styrene content of SBR is preferably 15% by mass or more, more preferably 18% by mass or more, and even more preferably 20% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0102] From the viewpoint of ensuring hysteresis loss, the vinyl content of SBR is preferably more than 12 mol%, more preferably more than 15 mol%, and even more preferably more than 18 mol%. From the viewpoint of fuel economy, the vinyl content of SBR is preferably less than 50 mol%, more preferably less than 45 mol%, and even more preferably less than 40 mol%. In this specification, the vinyl content of SBR is measured by the above-mentioned measurement method.

[0103] From the viewpoint of the effects of the present invention, the weight average molecular weight (Mw) of SBR is preferably more than 80,000, more preferably more than 100,000, even more preferably more than 150,000, and particularly preferably more than 500,000. Furthermore, from the viewpoint of crosslinking uniformity, etc., Mw is preferably less than 2,000,000, more preferably less than 1,500,000, and even more preferably less than 1,100,000. The Mw of SBR is measured by the above-mentioned measurement method.

[0104] From the viewpoint of the effects of the present invention, the content of SBR in the rubber component (when two or more types are used in combination, the total content of all SBRs) is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more. The content of SBR in the rubber component is preferably 60% by mass or less, more preferably less than 60% by mass, and even more preferably 50% by mass or less.

[0105] (BR) The BR is not particularly limited, and can be one commonly used in the tire industry, such as BR with a cis content of less than 50 mol% (low-cis BR), BR with a cis content of 90 mol% or more (high-cis BR), rare earth butadiene rubber (rare earth BR) synthesized using a rare earth catalyst, BR containing syndiotactic polybutadiene crystals (SPB-containing BR), modified BR (high-cis modified BR, low-cis modified BR), etc. These BRs may be used alone or in combination of two or more.

[0106] As the high-cis BR, for example, commercially available products from Zeon Corporation, UBE Corporation, JSR Corporation, etc. can be used. The inclusion of high-cis BR can improve low-temperature properties and wear resistance. The cis content of the high-cis BR is preferably more than 95 mol%, more preferably more than 96 mol%, and even more preferably more than 97 mol%. The cis content of BR is measured by the above-mentioned measurement method.

[0107] The rare earth BR is synthesized using a rare earth catalyst and has a vinyl content of preferably less than 1.8 mol%, more preferably less than 1.6 mol%, and even more preferably 1.5 mol% or less, and a cis content of preferably more than 95 mol%, more preferably more than 96 mol%, and even more preferably 97 mol% or more. As the rare earth BR, for example, commercially available products from LANXESS K.K. can be used.

[0108] The SPB-containing BR is not one in which 1,2-syndiotactic polybutadiene crystals are simply dispersed in the BR, but one in which the 1,2-syndiotactic polybutadiene crystals are dispersed after being chemically bonded to the BR. As such SPB-containing BR, commercially available products from UBE Corporation and the like can be used.

[0109] Examples of modified BR include BR modified with functional groups similar to those described above for SBR, and also preferably used are modified butadiene rubbers (modified BRs) whose terminals and / or main chains are modified with functional groups containing at least one element selected from the group consisting of silicon, nitrogen, and oxygen.

[0110] Other examples of modified BR include tin-modified BR, which is obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, and in which the terminals of the modified BR molecule are further bonded with a tin-carbon bond (tin-modified BR).Modified BR may be either non-hydrogenated or hydrogenated.

[0111] From the viewpoint of abrasion resistance, the weight-average molecular weight (Mw) of BR is preferably more than 300,000, more preferably more than 350,000, and even more preferably more than 400,000. From the viewpoint of crosslink uniformity, etc., it is preferably less than 2,000,000, more preferably less than 1,000,000, and even more preferably less than 700,000. Mw can be determined by the above-mentioned method.

[0112] From the viewpoint of the effects of the present invention, the content of BR in the rubber component (when two or more types are used in combination, the total content of all BRs) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and still more preferably 40% by mass or more. Also, the content of BR in the rubber component is preferably 70% by mass or less, more preferably 60% by mass or less, and still more preferably 58% by mass or less.

[0113] (Isoprene rubber) Examples of isoprene-based rubbers that can be used include those commonly used in the tire industry, such as isoprene rubber (IR) and natural rubber. Natural rubber includes unmodified natural rubber (NR) as well as modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), highly purified natural rubber, and grafted natural rubber. These isoprene-based rubbers may be used alone or in combination of two or more.

[0114] The NR is not particularly limited, and those commonly used in the tire industry can be used, such as SIR20, RSS#3, and TSR20.

[0115] When an isoprene-based rubber is contained, the content in the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or less. From the viewpoint of compounding other rubber components, the content of the isoprene-based rubber is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. The rubber component does not necessarily contain an isoprene-based rubber.

[0116] (Other rubber components) The rubber component may contain rubber components other than isoprene-based rubber, SBR, and BR, as long as the effects of the invention are not affected. Examples of other rubber components include rubber components commonly used in the tire industry, such as ethylene propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), and hydrin rubber. These other rubber components may be used alone or in combination of two or more. In addition to the above rubber components, known thermoplastic elastomers may or may not be included.

[0117] (Rubber components synthesized from recycled and biomass-derived raw materials) Monomers, which are structural units of synthetic rubbers such as IR, SBR, and BR, may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene. Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. Among these, recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are preferably used as raw materials.

[0118] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0119] Furthermore, the monomers that are the structural units of polymers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to materials derived from natural resources such as plants. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0120] Monomers derived from biomass (biomass monomers) are not particularly limited, and examples thereof include biomass-derived butadiene and biomass-derived aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. The method for producing biomass monomers is not particularly limited, and examples include biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0121] Polymers synthesized from biomass monomer components (biomass polymers) are not particularly limited and include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compounds, etc. Examples of the aromatic vinyl / butadiene copolymers include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0122] Whether a polymer's raw material is biomass-derived can be determined by its pMC (percent modern carbon) measured in accordance with ASTM D 6866-10. pMC is the modern standard reference carbon. 14 of sample against C concentration 14This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0123] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14 C exists. 14 The half-life of C is 5730 years, 14 C is decreasing regularly. Therefore, in the case of fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when they were first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C element.

[0124] on the other hand, 14 C is constantly produced by cosmic rays undergoing nuclear reactions in the atmosphere. 14 The amount of C is balanced between radioactive decay and nuclear reaction, and in the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio in a compound can be calculated by using the difference between these values.

[0125] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12C) is measured. 14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14 The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0126] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, it will usually not reach 100 under normal conditions, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0127] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0128] [Filler] The rubber composition according to the present embodiment contains a filler, and the filler preferably contains carbon black and / or silica, more preferably carbon black and silica, or may contain only carbon black and silica.

[0129] <Carbon black> Carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by thermal decomposition of methane, such as in a thermal black process. Commercially available carbon black products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Co., Ltd. One type of carbon black may be used alone, or two or more types may be used in combination.

[0130] In addition to the above, from the viewpoint of life cycle assessment, carbon black may be made from a biomass material such as lignin, or recycled carbon black obtained by pyrolysis and purification of a product containing carbon black, such as a tire.

[0131] As used herein, "recycled carbon black" refers to carbon black obtained by crushing used tires or other products containing carbon black and calcining the crushed material, and refers to carbon black in which, when subjected to oxidative combustion by heating in air as measured by thermogravimetry in accordance with JIS K 6226-2:2003, the proportion of the mass of ash (ash content), which is the non-combustible component, is 13% by mass or more. In other words, the proportion of the mass (carbon content) of the recycled carbon black lost due to oxidative combustion is 87% by mass or less. Recycled carbon black is sometimes expressed as rCB.

[0132] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975, citing "Rubber Chemistry and Technology," Vol. 85, No. 3, pp. 408-449 (2012), particularly pp. 438, 440, and 442, describes the carbon black as being obtained by pyrolysis of organic materials at 550-800°C in the absence of oxygen, or by vacuum pyrolysis at relatively low temperatures (

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

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

[0133] Recycled carbon black may lack functional groups on its surface, or may be treated to include functional groups on its surface. Treatment to include functional groups on the surface of recycled carbon black can be carried out by conventional methods. For example, European Patent Application Publication No. 3,173,251 discloses treating carbon black obtained by a pyrolysis process with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl and / or carboxyl groups on its surface. Furthermore, Japanese Patent No. 6,856,781 discloses treating carbon black obtained by a pyrolysis process with an amino acid compound containing at least one thiol or disulfide group to obtain surface-activated carbon black. The recycled carbon black of this embodiment also includes carbon blacks treated to include functional groups on their surfaces.

[0134] As the recycled carbon black, commercially available products from Strable Green Carbon, LD Carbon, etc. can be used.

[0135] From the perspective of reinforcement, the nitrogen adsorption specific surface area (N2SA) of carbon black is 100m 2 / g or more is preferable, and 120m2 / g is more preferable, and 130m 2 / g or more is more preferable, and 140m 2 From the viewpoint of heat buildup and processability, it is particularly preferable that the tensile strength is more than 250 m / g. 2 / g is preferable, and 200m 2 / g is more preferable, and 180m 2 / g or less is more preferable. The N2SA of carbon black is measured by the above-mentioned measurement method.

[0136] From the viewpoint of the effects of the present invention, the average primary particle diameter of carbon black is preferably 60 nm or less, more preferably 50 nm or less, even more preferably 40 nm or less, still more preferably 20 nm or less, even more preferably 19 nm or less, still more preferably 18 nm or less, and particularly preferably less than 18 nm. Furthermore, the average primary particle diameter is preferably greater than 12 nm, more preferably greater than 15 nm. The average primary particle diameter of carbon black is measured by the above-mentioned measurement method.

[0137] The amount of carbon black per 100 parts by mass of the rubber component is preferably more than 5 parts by mass, more preferably more than 8 parts by mass, and even more preferably 10 parts by mass or more, and is preferably less than 60 parts by mass, more preferably less than 30 parts by mass, and even more preferably less than 25 parts by mass.

[0138] <Silica> The silica is not particularly limited, and can be, for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrated silica), or other silica commonly used in the tire industry. The raw material for silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from a silica-containing product. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. Silica can be used alone or in combination of two or more types.

[0139] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0140] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0141] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, the crystallization of silica in rice husk ash can be suppressed (see, for example, JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222). Amorphous silica extracted from rice husks can be commercially available from Wilmar, Inc.

[0142] From the viewpoint of reinforcement, the nitrogen adsorption specific surface area (N2SA) of silica is 100m 2 / g or more is preferable, and 120m 2 / g is more preferable, and 150m 2 / g or more is more preferable, and 170m 2 From the viewpoint of heat buildup and processability, it is particularly preferable that the tensile strength is more than 250 m / g. 2 / g is preferable, and 200m 2 / g is more preferable, and 180m 2 / g or less is more preferable. The N2SA of silica is measured by the above-mentioned measurement method.

[0143] The average primary particle size of silica is preferably greater than 8 nm, more preferably greater than 10 nm, and even more preferably greater than 12 nm. The average primary particle size is preferably less than 21 nm, more preferably less than 20 nm, and even more preferably less than 18 nm. The average primary particle size of silica is measured by the above-mentioned measurement method.

[0144] From the viewpoint of the effects of the present invention, the content of silica per 100 parts by mass of the rubber component is preferably more than 15 parts by mass, more preferably more than 30 parts by mass, even more preferably more than 50 parts by mass, still more preferably more than 60 parts by mass, and particularly preferably more than 80 parts by mass. Also, from the viewpoint of processability, the content is preferably less than 150 parts by mass, more preferably less than 140 parts by mass, and even more preferably less than 120 parts by mass.

[0145] The mass ratio of silica to carbon black is preferably greater than 1.0, more preferably greater than 2.0, even more preferably greater than 5.0, particularly preferably greater than 8.0, and most preferably greater than 10.0.

[0146] <Other fillers> The filler may contain fillers other than silica and carbon black. The other fillers are not particularly limited, but may include, for example, fillers commonly used in the tire industry, such as aluminum hydroxide, calcium carbonate, alumina, clay, and talc.

[0147] (Silane coupling agent) Silica is preferably used in combination with a silane coupling agent.The silane coupling agent is not particularly limited, and any silane coupling agent that is conventionally used in combination with silica in the tire industry can be used, for example, the following mercapto-based silane coupling agents: sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide; thioester-based silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, 3-octanoylthio-1-propyltrimethoxysilane; vinyltriethoxysilane, ... Examples of suitable silane coupling agents include vinyl-based silane coupling agents such as methoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, sulfide-based silane coupling agents and / or mercapto-based silane coupling agents are preferred. These silane coupling agents may be used alone or in combination.

[0148] The mercapto-based silane coupling agent is preferably a compound represented by the following chemical formula (1) and / or a compound containing a bonding unit A represented by the following chemical formula (2) and a bonding unit B represented by the following chemical formula (3). [ka] (In the formula, R 101 , R 102 , and R 103 are each independently an alkyl having 1 to 12 carbon atoms, an alkoxy having 1 to 12 carbon atoms, or -O-(R111 -O) z -R 112 (z R 111 each independently represents a divalent hydrocarbon group having 1 to 30 carbon atoms; R 112 represents an alkyl having 1 to 30 carbon atoms, an alkenyl having 2 to 30 carbon atoms, an aryl having 6 to 30 carbon atoms, or an aralkyl having 7 to 30 carbon atoms; z represents an integer of 1 to 30; 104 represents an alkylene having 1 to 6 carbon atoms. [ka] [ka] (wherein x represents an integer of 0 or more; y represents an integer of 1 or more; R 201 represents a hydrogen atom, or an alkyl having 1 to 30 carbon atoms, an alkenyl having 2 to 30 carbon atoms, or an alkynyl having 2 to 30 carbon atoms (the alkyl, alkenyl, and alkynyl may each be substituted with a halogen atom, a hydroxyl, or a carboxyl); R 202 represents an alkylene having 1 to 30 carbon atoms, an alkenylene having 2 to 30 carbon atoms, or an alkynylene having 2 to 30 carbon atoms; 201 and R 202 may form a ring structure with

[0149] Examples of the compound represented by formula (1) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the compound represented by the following chemical formula (4) (Si363 manufactured by Evonik Degussa GmbH), and the compound represented by the following chemical formula (4) can be preferably used. These may be used alone or in combination of two or more. [ka]

[0150] Examples of compounds containing a linking unit A represented by formula (2) and a linking unit B represented by formula (3) include NXT-Z30, NXT-Z45, NXT-Z60, and NXT-Z100 manufactured by Momentive Corp. These may be used alone or in combination of two or more.

[0151] [Other compounding agents] In addition to the rubber component and filler, the rubber composition may contain, as appropriate, compounding agents that are generally used in the tire industry, such as plasticizers, processing aids, vulcanized rubber particles, wax, stearic acid, zinc oxide, antioxidants, vulcanizing agents, and vulcanization accelerators.

[0152] <Plasticizer> A plasticizer is a material that imparts plasticity to rubber components, and the term encompasses both plasticizers that are liquid at 25°C and plasticizers that are solid at 25°C. Examples of plasticizers include resin components, oils, liquid rubbers, and ester-based plasticizers. These plasticizers may be derived from mineral resources such as petroleum and natural gas, or may be derived from biomass. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. Plasticizers may be used singly or in combination.

[0153] (resin component) Among the other compounding ingredients, the rubber composition preferably contains a resin component. The resin component is not particularly limited, but resins commonly used in the tire industry can be used, such as aromatic vinyl resins, dicyclopentadiene resins, C9 resins, C5 resins, C5C9 resins, terpene resins, rosin resins, and phenolic resins. Of these, aromatic vinyl resins, C9 resins, and terpene resins are preferred. The resin component may be used alone or in combination of two or more.

[0154] <Aromatic vinyl resin> The term "aromatic vinyl resin" refers to a resin containing at least one aromatic vinyl compound selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, etc., as the monomer component with the highest content, and may be a hydrogenated or modified version of such a compound. As the aromatic vinyl resin, a homopolymer of α-methylstyrene or styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, because they are economical, easy to process, and have excellent heat generation properties. As the aromatic vinyl resin, for example, commercially available products from Kraton, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used. The aromatic vinyl resin may be used alone or in combination of two or more types.

[0155] <Dicyclopentadiene resin> The term "dicyclopentadiene-based resin" refers to a resin containing dicyclopentadiene (DCPD) as the monomer component with the highest content, and may be a hydrogenated or modified resin. Examples of dicyclopentadiene-based resins include DCPD / C9 resins obtained by copolymerizing dicyclopentadiene with the C9 fraction, with DCPD / C9 resins being preferred. Examples of DCPD resins that can be used include those commercially available from ExxonMobil Corporation, ENEOS Corporation, Nippon Zeon Co., Ltd., Maruzen Petrochemical Co., Ltd., and the like. One type of dicyclopentadiene-based resin may be used alone, or two or more types may be used in combination.

[0156] <C9 resin> The term "C9 resin" refers to a resin obtained by polymerizing a C9 fraction. It may be a C9 fraction polymerized alone or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. These resins may also be hydrogenated or modified. Examples of C9 fractions include at least one petroleum fraction having 8 to 10 carbon atoms selected from the group consisting of vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene. Specific examples of C9 resins include coumarone-indene resin, coumarone resin, and indene resin. One type of C9 resin may be used alone, or two or more types may be used in combination.

[0157] <C5 resin> "C5 resin" refers to a resin obtained by polymerizing a C5 fraction other than dicyclopentadiene, and may be a hydrogenated or modified version of such a resin. Examples of C5 fractions other than dicyclopentadiene include at least one petroleum fraction having 4 to 5 carbon atoms selected from the group consisting of cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, pentadiene, etc. The C5 resin may be used alone or in combination of two or more types.

[0158] <C5C9 resin> The term "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be a hydrogenated or modified resin. As the C5C9 resin, for example, commercially available resins from Tosoh Corporation, LUHUA, etc. may be used. The C5C9 resin may be used alone or in combination of two or more.

[0159] <Terpene resin> The term "terpene resin" refers to a resin containing at least one terpene compound selected from the group consisting of α-pinene, β-pinene, limonene, dipentene, etc., as the most abundant monomer component, preferably at least 50 mol %, and may be hydrogenated or modified. Specific examples of terpene resins include polyterpene resins containing only one or more of the terpene compounds as monomer components; aromatic-modified terpene resins containing the terpene compound and an aromatic compound as monomer components; and terpene phenolic resins containing the terpene compound and a phenolic compound as monomer components. Examples of aromatic compounds that serve as monomer components for aromatic-modified terpene resins include at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include at least one selected from the group consisting of phenol, bisphenol A, cresol, xylenol, etc. These terpene resins may be used alone or in combination.

[0160] <Rosin-based resin> Terpene resins refer to resins containing at least one terpene compound selected from the group consisting of α-pinene, β-pinene, limonene, dipentene, etc., as the most abundant monomer component, preferably at least 50 mol %, and may be hydrogenated or modified. Specific examples of terpene resins include polyterpene resins containing only one or more of the terpene compounds as monomer components; aromatic-modified terpene resins containing the terpene compound and an aromatic compound as monomer components; and terpene phenolic resins containing the terpene compound and a phenolic compound as monomer components. Examples of aromatic compounds that serve as monomer components for aromatic-modified terpene resins include at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include at least one selected from the group consisting of phenol, bisphenol A, cresol, xylenol, etc. Terpene resins may be used alone or in combination.

[0161] <Phenol-based resin> Terpene resins refer to resins containing at least one terpene compound selected from the group consisting of α-pinene, β-pinene, limonene, dipentene, etc., as the most abundant monomer component, preferably at least 50 mol %, and may be hydrogenated or modified. Specific examples of terpene resins include polyterpene resins containing only one or more of the terpene compounds as monomer components; aromatic-modified terpene resins containing the terpene compound and an aromatic compound as monomer components; and terpene phenolic resins containing the terpene compound and a phenolic compound as monomer components. Examples of aromatic compounds that serve as monomer components for aromatic-modified terpene resins include at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include at least one selected from the group consisting of phenol, bisphenol A, cresol, xylenol, etc. Terpene resins may be used alone or in combination.

[0162] ≪Softening point≫ From the viewpoint of grip performance, the softening point of the resin component is preferably 60° C. or higher, more preferably 70° C. or higher, and even more preferably 80° C. or higher. From the viewpoint of processability and improving the dispersibility of the rubber component and the filler, the softening point is preferably 150° C. or lower, more preferably 140° C. or lower, and even more preferably 130° C. or lower. The softening point of the resin component is measured by the above-mentioned measurement method.

[0163] (Plasticizers other than resin components) The plasticizers other than the resin component, such as oil, liquid rubber, and ester-based plasticizers, will now be described.

[0164] (oil) Examples of oils include mineral oil, vegetable oil, and animal oil. From the viewpoint of life cycle assessment, waste oils used in rubber mixers and engines, and refined waste cooking oils used in restaurants may also be used. One type of oil may be used alone, or two or more types may be used in combination.

[0165] As used herein, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil. Specific examples of mineral oil include mild extracted solvate (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, oils with a low content of polycyclic aromatic compounds (PCA) can also be used as an environmentally friendly measure. Examples of low PCA oils include MES, TDAE, and heavy naphthenic oil. Mineral oils may be used singly or in combination.

[0166] As used herein, examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above oils, interesterified oils obtained by interesterifying the above oils, hardened oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, and waste edible oils recovered from edible oils and the like. Vegetable oils may be liquid or solid at 25°C. One vegetable oil may be used alone, or two or more may be used in combination.

[0167] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is esterified with a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. The acylglycerol may be liquid or solid at 25°C.

[0168] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is esterified with a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. The acylglycerol may be liquid or solid at 25°C.

[0169] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, the 1When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0170] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0171] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., saturated fatty acid or monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing saturated fatty acid or monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0172] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0173] Examples of animal oils include fish oil, beef tallow, whale oil, and oleyl alcohol derived from these.

[0174] When oil is contained, the content per 100 parts by mass of the rubber component is preferably more than 15 parts by mass, more preferably more than 20 parts by mass, and even more preferably more than 30 parts by mass from the viewpoint of processability, and is preferably less than 100 parts by mass, more preferably less than 70 parts by mass, and even more preferably less than 50 parts by mass from the viewpoint of abrasion resistance.

[0175] (liquid rubber) The liquid rubber is not particularly limited as long as it is a polymer that is in a liquid state at 25° C., and examples thereof include liquid butadiene rubber (liquid BR), liquid styrene butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene isoprene rubber (liquid SIR), liquid farnesene rubber, etc. One type of liquid rubber may be used alone, or two or more types may be used in combination.

[0176] (ester plasticizer) Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di-2-ethylhexyl azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), and trixylenyl phosphate (TXP). One type of ester-based plasticizer may be used alone, or two or more types may be used in combination.

[0177] The amount of plasticizer per 100 parts by mass of the rubber component (the total amount when multiple plasticizers are used) is preferably more than 40 parts by mass, more preferably more than 50 parts by mass, and even more preferably more than 60 parts by mass. From the viewpoint of processability, the amount is preferably less than 110 parts by mass, more preferably less than 100 parts by mass, and even more preferably less than 90 parts by mass. The amount of plasticizer also includes the amount of extension plasticizers such as extension oil, extension resin, extension liquid rubber component, and extension ester-based plasticizer used to extend the rubber component.

[0178] (vulcanized rubber particles) The vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. One type of vulcanized rubber particle may be used alone, or two or more types may be used in combination.

[0179] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0180] As commercially available vulcanized rubber, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., etc. can be used.

[0181] (processing aids) Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. These processing aids may be used alone or in combination of two or more. Examples of processing aids that can be used include those commercially available from Schill + Seilacher, Performance Additives, etc.

[0182] When a processing aid is contained, the content thereof per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of improving processability, and is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance and breaking strength.

[0183] (wax) The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used, such as mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. The wax according to this embodiment does not contain stearic acid. Waxes commercially available from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., etc. can be used. One type of wax may be used alone, or two or more types may be used in combination.

[0184] When wax is contained, the content per 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 weather resistance of the rubber, and is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass, from the viewpoint of preventing whitening of the tire due to bloom.

[0185] (stearic acid) When stearic acid is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of processability, and is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of vulcanization rate.

[0186] (zinc oxide) When zinc oxide is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of processability, and preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance.

[0187] (anti-aging agent) The antioxidant is not particularly limited, but examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl ... p-phenylenediamine-based antioxidants such as diphenyldiamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., and Flexis Co., Ltd. One type of antioxidant may be used alone, or two or more types may be used in combination.

[0188] When an antioxidant is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.8 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of ozone crack resistance of the rubber, and is preferably less than 5.0 parts by mass, more preferably less than 4.0 parts by mass, and even more preferably less than 3.5 parts by mass from the viewpoint of abrasion resistance and wet grip performance.

[0189] (vulcanizing agent) Sulfur is preferably used as the vulcanizing agent. Examples of sulfur that can be used include powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. The vulcanizing agent may be used alone or in combination of two or more.

[0190] When sulfur is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 0.8 parts by mass, even more preferably more than 1.0 parts by mass, and particularly preferably more than 1.2 parts by mass, from the viewpoint of ensuring a sufficient vulcanization reaction. Furthermore, from the viewpoint of preventing deterioration, the content is preferably less than 5.0 parts by mass, more preferably less than 4.0 parts by mass, even more preferably less than 3.0 parts by mass, and particularly preferably less than 2.0 parts by mass. When oil-containing sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is the total content of pure sulfur contained in the oil-containing sulfur.

[0191] Known organic crosslinking agents can also be used as vulcanizing agents other than sulfur. The organic crosslinking agent is not particularly limited as long as it can form crosslinked chains other than polysulfide bonds. Examples of the organic crosslinking agent include alkylphenol-sulfur chloride condensate, sodium 1,6-hexamethylene-dithiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and dicumyl peroxide. 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane is preferred. These organic crosslinking agents can be commercially available from Taoka Chemical Co., Ltd., Lanxess K.K., Flexis, and other companies.

[0192] (Vulcanization accelerator) The vulcanization accelerator is not particularly limited, but examples thereof include sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, guanidine vulcanization accelerators, thiuram vulcanization accelerators, thiourea vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehyde-amine vulcanization accelerators, aldehyde-ammonia vulcanization accelerators, imidazoline vulcanization accelerators, xanthate vulcanization accelerators, and caprolactam disulfide. These vulcanization accelerators may be used alone or in combination of two or more. Among them, one or more vulcanization accelerators selected from the group consisting of sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, and guanidine vulcanization accelerators are preferred, as they more suitably achieve the desired effects. The vulcanization accelerators may be used alone or in combination of two or more.

[0193] Examples of sulfenamide vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS).

[0194] Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole (MBT) or a salt thereof, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinothio)benzothiazole.

[0195] Examples of guanidine vulcanization accelerators include 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatechol borate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, and 1,3-di-o-cumenyl-2-propionylguanidine.

[0196] Examples of thiuram vulcanization accelerators include tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide (TMTM), dipentamethylene thiuram disulfide, and dipentamethylene thiuram tetrasulfide.

[0197] Examples of the thiourea vulcanization accelerator include thiourea compounds such as thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea and diorthotolylthiourea, N,N'-diphenylthiourea, trimethylthiourea and N,N'-diethylthiourea.

[0198] Examples of dithiocarbamate vulcanization accelerators include piperidinium pentamethylenedithiocarbamate (PPDC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), zinc dibutyldithiocarbamate (ZnBDC), zinc dibenzyldithiocarbamate (ZDBzC), zinc N-ethyl-N-phenyldithiocarbamate (ZnEPDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), sodium dibutyldithiocarbamate (NaBDC), copper dimethyldithiocarbamate (CuMDC), iron dimethyldithiocarbamate (FeMDC), and tellurium diethyldithiocarbamate (TeEDC).

[0199] When a vulcanization accelerator is contained, the content (total amount when multiple vulcanization accelerators are used) per 100 parts by mass of the rubber component is preferably more than 1.0 part by mass, more preferably more than 1.5 parts by mass, and even more preferably more than 2.0 parts by mass. The content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably less than 8 parts by mass, more preferably less than 6 parts by mass, and even more preferably less than 5 parts by mass.

[0200] In this specification, various materials containing carbon atoms (for example, rubber, oil, resin components, vulcanization accelerators, antioxidants, surfactants, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining such various materials from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0201] [Manufacturing] The rubber composition can be produced by a known method, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or an internal kneader (such as a Banbury mixer or kneader).

[0202] The kneading process may include, for example, a base kneading process in which compounding ingredients and additives other than the vulcanizing agent and vulcanization accelerator are kneaded, and a final kneading (F kneading) process in which the vulcanizing agent and vulcanization accelerator are added to the kneaded product obtained in the base kneading process and kneaded. Furthermore, the base kneading process may be divided into multiple processes as desired. When the base kneading process is divided, the method may be (1) a method in which some of the compounding ingredients and additives are pre-mixed to form a masterbatch, and then the remaining compounding ingredients and additives are added to the resulting masterbatch and kneaded, or (2) a method in which all of the compounding ingredients and additives to be kneaded in the base kneading process are kneaded at once, and then the kneaded product is remilled one or more times. In the above method (1), the number of masterbatches is not limited and may be two or more. Furthermore, when the number of masterbatches is two or more, all of the compounding ingredients and additives used in the base kneading process may be allocated to one of the masterbatches.

[0203] The kneading conditions are not particularly limited, but examples include a method in which the base kneading step involves kneading for 3 to 10 minutes at a discharge temperature of 150 to 170°C, and a method in which the final kneading step involves kneading for 1 to 5 minutes at 70 to 110°C. The vulcanization conditions are not particularly limited, but examples include a method in which vulcanization is carried out for 10 to 30 minutes at 150 to 200°C.

[0204] A tire having a tread portion made of a rubber composition can be manufactured by a conventional method. That is, the tire can be manufactured by extruding an unvulcanized rubber composition prepared by blending the above-mentioned components with a rubber component as needed to form a tread portion, laminating and molding the tread portion thus obtained together with other tire components in a tire building machine by a conventional method to form an unvulcanized tire, and then heating and pressurizing the unvulcanized tire thus obtained in a vulcanizer. The vulcanization conditions are not particularly limited, and examples include a method of vulcanizing at 150 to 200°C for 10 to 30 minutes.

[0205] [Application] The tire of this embodiment can be used for any purpose, regardless of whether it is a pneumatic tire or a non-pneumatic tire, and can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a racing tire, a motorcycle tire, a heavy-duty tire, or a run-flat tire. Passenger car tires are tires designed to be mounted on four-wheeled vehicles and have a maximum load capacity of less than 1,400 kg. Heavy-duty tires are tires with a maximum load capacity of 1,400 kg or more. The tire of this embodiment can be used as an all-season tire, a summer tire, or a winter tire such as a studless tire. [Example]

[0206] The following examples (working examples) are considered to be preferable for carrying out the present invention, but the scope of the present invention is not limited to these working examples. Tires obtained according to Table 1 or Table 2 using the various chemicals shown below were examined, and the results calculated based on the evaluation method described below are shown in Tables 1 and 2.

[0207] <Various chemicals> SBR1: SBR1502 manufactured by JSR Corporation (unmodified E-SBR, styrene content: 23.5% by mass, vinyl content: 18% by mole, Mw: 440,000, non-oil extended) SBR2: TUFDENE 3830 manufactured by Asahi Kasei Corporation (unmodified S-SBR, styrene content: 33% by mass, vinyl content: 34 mol%, Mw: 420,000, contains 37.5 parts by mass of oil-extended oil per 100 parts by mass of rubber solids) BR1: Asahi Kasei Corporation's ASAPRENE N103 (modified BR whose terminals are modified with a mixture of tetraglycidyl-1,3-bisaminomethylcyclohexane and its oligomer component, vinyl content: 12 mol%, cis content: 36 mol%, Mw: 550,000) BR2: UBEPOL-BR360B (high cis BR, vinyl content: 1.9 mol%, cis content: 98 mol%, Mw: 570,000) manufactured by UBE Corporation IR rubber: TSR20 (natural rubber) Carbon black: Show Black N134 (N2SA: 148m) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 18nm) Silica: Ultrasil VN3 (N2SA: 175 ml) manufactured by Evonik Degussa 2 / g, average primary particle diameter: 17nm) Silane coupling agent 1: Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) manufactured by Evonik Degussa Silane coupling agent 2: NXT-Z45 manufactured by Momentive (a silane coupling agent having a mercapto group, a copolymer of bonding unit A and bonding unit B (bonding unit A: 55 mol%, bonding unit B: 45 mol%)) Oil: H&R VivaTec 500 (TDAE oil) Resin component 1: YS Resin PX1150N (terpene resin, softening point: 115±5°C) manufactured by Yasuhara Chemical Co., Ltd. Resin component 2: Kraton SYLVATRAXX 4401 (α-methylstyrene resin, softening point: 85°C) Liquid rubber: Cray Valley RICON 100 (liquid SBR) Wax: Ozoace 0355 (paraffin wax) manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: Antigen 6C (6PPD, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd. Antioxidant 2: Nocrac 224 (TMQ, 2,2,4-trimethyl-1,2-dihydroquinoline polymer) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: Camellia stearic acid beads manufactured by NOF Corporation Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccelaer D (1,3-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0208] Examples and Comparative Examples According to the compounding recipes shown in Table 1 or Table 2, a 1.7 L closed-type Banbury mixer was used to knead all the chemicals except sulfur and the vulcanization accelerator at a discharge temperature of 160°C for 4 minutes to obtain a kneaded mixture. Next, using an open roll, sulfur and the vulcanization accelerator were added to the kneaded mixture, and the mixture was kneaded for 4 minutes until the temperature reached 105°C to obtain an unvulcanized rubber composition. The unvulcanized rubber composition obtained was molded to fit the shape of the tread portion, and then bonded together with other tire components to produce an unvulcanized tire. The tire was then vulcanized at 170°C to obtain each test tire (size: 205 / 65R15, rim: 15x6.5, internal pressure: 230 kPa).

[0209] <Measurement of glass transition temperature (Tg)> For each rubber test piece cut out from the inside of the rubber layer of the tread part of each test tire with a length of 20 mm, a width of 4 mm, and a thickness of 1 mm so that the tire circumferential direction is the long side, using an Implexer series manufactured by GABO, the temperature distribution curve of the loss tangent tanδ was measured under the conditions of a frequency of 10 Hz and a dynamic strain of ±2.5%, and the temperature (tanδ peak temperature) corresponding to the largest tanδ value in the obtained temperature distribution curve was taken as the glass transition temperature (Tg). The thickness direction of the sample is the tire radial direction.

[0210] <Temperature distribution curve of tanδ> For each rubber test piece, using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho Co., Ltd., the temperature distribution curve of tanδ was measured in the temperature range from -120°C to 70°C under the conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / min. Then, based on the obtained temperature distribution curve of tanδ, the half-width of the peak in the range of -20°C to -70°C was measured. The rubber test pieces were prepared in the same manner as when measuring the glass transition temperature (Tg).

[0211] <Measurement of 0°C tanδ and 0°C E*> For each rubber test piece, using an Implexer series manufactured by GABO, the loss tangent (0°C tanδ) and the complex elastic modulus (0°C E*) (unit: MPa) were measured under the conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and an elongation mode. The rubber test pieces were prepared in the same manner as when measuring the glass transition temperature (Tg).

[0212] <Measurement of 30°C tanδ> For each rubber test piece, using an Implexer series manufactured by GABO, the loss tangent (30°C tanδ) measured under the conditions of a temperature of 30°C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and an elongation mode was measured. The rubber test pieces were prepared in the same manner as when measuring the glass transition temperature (Tg).

[0213] <Measurement of 60°C tanδ> For each rubber test piece prepared in the same manner as for 0°C tanδ and 0°C E*, the loss tangent (60°C tanδ) is measured using an Iplexer series manufactured by GABO under the conditions of a temperature of 60°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±1%, and an extension mode. The rubber test piece is prepared in the same manner as for measuring the glass transition temperature (Tg).

[0214] <Measurement of acetone extractables (AE)> The AE amount is measured for each rubber test piece cut out from the tread of each test tire. The AE amount can be calculated by the following formula, after immersing each rubber test piece in acetone for 72 hours to extract the soluble components, and measuring the mass of each test piece before and after extraction. Acetone extractable amount (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0215] <Dry grip performance on low-temperature roads> Each test tire was fitted to all wheels of a vehicle, and the braking distance was measured from the point where the brakes were applied at a speed of 100 km / h under conditions of an outside temperature of 0 to 5°C and a dry asphalt road surface. The braking distance of the control tire (reference comparative example: Comparative Example 1) was set at 100, and the reciprocal of the braking distance of each test tire was expressed as an index using the following formula. A higher index indicates better dry grip performance on low-temperature road surfaces. (Dry grip performance index) = (braking distance of control tire) / (braking distance of each test tire)

[0216] [Table 1]

[0217] [Table 2]

[0218] <Embodiment> Examples of embodiments of the present invention are given below. [1] A tire having a tread portion, Maximum tire load capacity W L Ratio of tire weight G (kg) to tire weight (G / W L ) is less than or equal to 0.0170, The thickness T of the tread portion is 8.0 mm or less, the tread portion is made of a rubber composition including a rubber component, a filler, a plasticizer, and a crosslinking agent, The rubber composition has a glass transition temperature Tg of −30° C. or higher, Tg × T is greater than or equal to -220, The half width H of a peak in the range of −20° C. to −70° C. in a tanδ temperature distribution curve of the rubber composition is 60° C. or more, H / (G / W L ) is 3600 or more, tires. [2] H / (G / W L ) is 5500 or more, preferably 6000 or more, more preferably 6500 or more. [3] Golden Week L The tire according to [1] or [2] above, wherein the value is 0.0135 or less. [4] The tire according to any one of the above [1] to [3], wherein the ratio (0°C tanδ / T) of the loss tangent (0°C tanδ) of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz to T is 0.12 or less, preferably 0.10 or less, and more preferably 0.08 or less. [5] The tire according to any one of the above [1] to [4], wherein the product (0°C E* × T) of the complex modulus of elasticity of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz, and T is 70 or more, preferably 90 or more, and more preferably 100 or more. [6] The tire according to any one of the above [1] to [5], wherein the filler contains carbon black with an average primary particle diameter of 18 nm or less. [7] The filler comprises carbon black and silica; The tire according to any one of the above [1] to [6], wherein the mass ratio of the silica to the carbon black exceeds 1.0. [8] The tire according to any one of the above [1] to [7], wherein AE / G is less than 4.0, where AE (mass%) is the acetone extractable amount of the rubber composition. [9] The tread surface of the tread portion has one or more circumferential grooves extending continuously in the tire circumferential direction, and two or more land portions defined by the circumferential grooves and the ground contact edge, The land portion has a lateral groove extending in the tire width direction, The tire according to any one of [1] to [8] above, wherein the lateral grooves have a portion where the groove width in a cross section perpendicular to the tire radial direction is wider than the groove width on the tread surface.

[10] The tread surface of the tread portion has one or more circumferential grooves extending continuously in the tire circumferential direction, and two or more land portions defined by the circumferential grooves and the ground contact edge, The tire according to any one of [1] to [9] above, wherein the ratio of the area of ​​the circumferential grooves to the area of ​​the tread contact patch is more than 19% and less than 32%, preferably 20% or more and 30% or less, and more preferably 22% or more and 38% or less.

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

[10] , wherein the product (30°C tanδ × 0°C tanδ) of the loss tangent of the rubber composition measured under conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of 1%, and a frequency of 10 Hz and the loss tangent of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz is greater than 0.11, preferably 0.12 or more, more preferably 0.13 or more, and even more preferably 0.15 or more.

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

[11] , wherein the content of butadiene rubber in the rubber component is more than 0 and not more than 60% by mass, preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 58% by mass or less.

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

[12] , wherein the rubber composition contains a mercapto-based silane coupling agent.

[14] The loss tangent of the rubber composition measured under the conditions of a temperature of 30 ° C, an initial strain of 5%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is 30 ° C tan δ, When the loss tangent of the rubber composition measured under the conditions of a temperature of 60°C, an initial strain of 10%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is 60°C tanδ, (30℃ tanδ - 60℃ tanδ) / T is 8.75×10 -3 Less than 8.50 x 10 -3 The tire according to any one of the above [1] to

[13] , wherein the axial length is less than 1 / 2 mm. [Explanation of symbols]

[0219] Wt Tire section width Ht Tire section height Dt Tire outer diameter 1 Circumferential groove 2 Land 3 Tread surface 4 Straight line connecting the ends of circumferential grooves 6 First layer 7 Second layer 8 Extension of the outer surface of the second layer t1 Thickness of the first layer t2 Second layer thickness T Tread thickness P Midpoint in tire width direction N A line perpendicular to the tangent plane at point P 11 Center circumferential groove 12 Outermost groove 13 Outermost groove 21 Center Land Section 22 Center Land Section 23 Shoulder land area 24 Shoulder Land Section 31 Widening horizontal groove 32 Widening horizontal groove 33 Widening Horizontal Groove 34 Widening horizontal groove 35 Center Yokomizo 36 Center Yokomizo 37 Shoulder groove 38 Shoulder groove Te tread edge EP tire equatorial plane

Claims

1. A tire having a tread portion, Maximum tire load capacity W L Ratio of tire weight G (kg) to tire weight (kg) (G / W L ) is 0.0170 or less, The thickness T of the tread portion is 8.0 mm or less, the tread portion is made of a rubber composition including a rubber component, a filler, a plasticizer, and a crosslinking agent, The glass transition temperature Tg of the rubber composition is −30° C. or higher, Tg×T is −220 or more, The half width H of a peak in the range of −20° C. to −70° C. in a tan δ temperature distribution curve of the rubber composition is 60° C. or more, H / (G / W L ) is 3600 or more.

2. H / (G / W L 2. The tire of claim 1, wherein the tensile strength of the tire is 5,500 or greater.

3. Golden Week L 3. The tire according to claim 1, wherein the ρ is 0.0135 or less.

4. 3. The tire according to claim 1, wherein the ratio (0°C tanδ / T) of the loss tangent (0°C tanδ) of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz to T is 0.12 or less.

5. 3. The tire according to claim 1, wherein the product (0°C E* x T) of the complex modulus of elasticity of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of ±2.5%, and a frequency of 10 Hz is 70 or more.

6. The tire according to claim 1 or 2, wherein the filler contains carbon black with an average primary particle diameter of 18 nm or less.

7. the filler comprises carbon black and silica; 3. The tire of claim 1 or 2, wherein the mass ratio of said silica to said carbon black is greater than 1.

0.

8. The tire according to claim 1 or 2, wherein AE (mass%) of the acetone extractable amount of the rubber composition is AE / G of less than 4.

0.

9. The tread surface of the tread portion has one or more circumferential grooves extending continuously in the tire circumferential direction, and two or more land portions defined by the circumferential grooves and a ground contact edge, The land portion has a lateral groove extending in the tire width direction, The tire according to claim 1 or 2, wherein the lateral grooves have a portion in which the groove width in a cross section perpendicular to the tire radial direction is wider than the groove width on the tread surface.

10. The tread surface of the tread portion has one or more circumferential grooves extending continuously in the tire circumferential direction, and two or more land portions defined by the circumferential grooves and a ground contact edge, The tire according to claim 1 or 2, wherein a ratio of an area of ​​the circumferential groove to an area of ​​the tread contact patch is more than 19% and less than 32%.

11. 3. The tire according to claim 1, wherein the product (30°C tan δ × 0°C tan δ) of the loss tangent of the rubber composition measured under conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of 1%, and a frequency of 10 Hz and the loss tangent of the rubber composition measured under conditions of a temperature of 0°C, an initial strain of 10%, a dynamic strain of 2.5%, and a frequency of 10 Hz exceeds 0.

11.

12. The tire according to claim 1 or 2, wherein the content of the butadiene rubber in the rubber component is more than 0 and not more than 60% by mass.

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

14. The loss tangent of the rubber composition measured under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is 30°C tanδ, When the loss tangent of the rubber composition measured under the conditions of a temperature of 60°C, an initial strain of 10%, a dynamic strain of ±1.0%, and a frequency of 10 Hz is defined as 60°C tanδ, (30°C tan δ - 60°C tan δ) / T is 8.75 × 10 -3 3. The tire of claim 1 or 2, wherein the axial length is less than 1 / 2 .

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