TIRES

Abstract

pneumatic tire, which includes a tread section, wherein the tread section is made up of a rubber composition comprising a rubber component and silicon dioxide, where the content of an isoprene-based rubber in the rubber component is greater than 40% by mass, where the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, and where 30 °C-ΔE* (0.25 % - 1.0 %) represents a difference between a complex modulus of elasticity at a dynamic strain of 0.25 % and a complex modulus of elasticity at a dynamic strain of 1.0 %, measured under a condition of a temperature of 30 °C, a frequency of 10 Hz and an initial strain of 5 %, of the rubber composition, and T in mm represents a thickness of the tread section, 30 °C − Δ E * ( 0.25 % − 1.0 % ) 6.0 MPa or more is ¨ gt , and 30 °C − Δ E * ( 0.25 % − 1.0 % ) / T 0.45 or more is ¨ gt .

Description

TECHNICAL AREA

[0001] The present invention relates to a tire. BACKGROUND OF THE INVENTION

[0002] Recently, attempts have been made to reduce the heat generation of a pneumatic tire by combining a modified styrene-butadiene rubber or silicon dioxide (for example, JP 2014-80521 A), with a view to fuel efficiency, etc. SUMMARY OF THE INVENTION

[0003] On the other hand, with recent advances in motorway construction, it is not uncommon to drive long distances at high speeds, and a pneumatic tire has been required to exhibit steering stability during high-speed driving.

[0004] One object of the present invention is to provide a pneumatic tire that exhibits improved steering stability during high-speed operation.

[0005] The present invention relates to: a pneumatic tire that includes a tread section, wherein the tread section is made up of a rubber composition comprising a rubber component and silicon dioxide, where the content of an isoprene-based rubber in the rubber component is greater than 40% by mass, where the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, and where 30 °C-ΔE* (0.25 % - 1.0 %) represents a difference between a complex modulus of elasticity at a dynamic strain of 0.25 % and a complex modulus of elasticity at a dynamic strain of 1.0 %, measured under a condition of a temperature of 30 °C, a frequency of 10 Hz and an initial strain of 5 %, of the rubber composition, and T in mm represents a thickness of the tread section, 30 °C-ΔE* (0.25 % - 1.0 %) 6.0 MPa or more, and 30 °C-ΔE* (0.25 % - 1.0 %) / T 0.45 or more.

[0006] According to the present invention, a pneumatic tire is provided which has improved steering stability during high-speed operation. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a schematic unfolded view of a tread section of a tire according to an embodiment of the present invention. Fig. Figure 2 is a schematic unfolded view of a tread section of a tire according to an embodiment of the present invention. Fig. Figure 3 is a cross-sectional view of a part of a tread section of a tire according to an embodiment of the present invention along a plane passing through a tire rotation axis. DETAILED DESCRIPTION

[0007] The tire according to one embodiment of the present invention is a pneumatic tire comprising a tread section, wherein the tread section is composed of a rubber composition comprising a rubber component and silicon dioxide, wherein the content of an isoprene-based rubber in the rubber component is greater than 40 wt%, wherein the content of silicon dioxide based on 100 wt% of the rubber component in the rubber composition is greater than 30 wt%, wherein, where 30 °C-ΔE* (0.25% - 1.0%) represents a difference between a complex modulus of elasticity at a dynamic strain of 0.25% and a complex modulus of elasticity at a dynamic strain of 1.0%, measured under conditions of a temperature of 30 °C, a frequency of 10 Hz and an initial strain of 5%, of the rubber composition, and where T in mm represents a thickness of the tread section, 30 °C-ΔE* (0.25% - 1.0%) 6,0 MPa or more and 30 °C-ΔE* (0.25 % - 1.0 %) / T 0.45 or more.

[0008] Although it is not intended to adhere to any particular theory, the following, for example, may be regarded as a mechanism for improving steering stability during high-speed running in the pneumatic tire of the present invention.

[0009] Since silicon dioxide is a hydrophilic filler, (1) if the rubber component comprises an isoprene-based rubber and the silicon dioxide content is more than 30 parts by mass of the rubber component (based on 100 parts by mass), a polymer chain present around silicon dioxide can be reinforced, and an area where silicon dioxide is aggregated can be formed when silicon dioxide is incorporated into the isoprene-based rubber. Therefore, it becomes possible to increase 30 °C-ΔE* (0.25% - 1.0%).

[0010] During high-speed driving, the tire reaches a state in which a ground contact area of ​​the tread section that comes into contact with a road surface undergoes a large amount of deformation when the weight of a vehicle is applied to irregularities of the road surface, while the interior of the tread section undergoes a relatively small amount of deformation when the weight of the vehicle is applied for a short period of time due to high-speed driving.Therefore, (2) by adjusting 30 °C-ΔE* (0.25% - 1.0%) to 6.0 MPa or more, a state in which the complex modulus of elasticity is high for low deformation and a state in which the complex modulus of elasticity is low for large deformation can be maintained, thus improving responsiveness while improving the tracking ability of the tread section's contact area with the road surface. Furthermore, since the strength of a rubber molecule is high in the isoprene-based rubber, (3) by adjusting the content of the isoprene-based rubber in the rubber component to more than 40 wt%, a reaction force at the time of reaction is increased.Furthermore, (4) can be improved by increasing 30 °C-ΔE* (0.25 % - 1.0 %) relative to the thickness T in mm of the running surface section and by adjusting 30 °C-ΔE* (0.25 % - 1.0 %) / T to 0.45 or more, while shortening a transmission distance of a force from an introduction to reaction.

[0011] It is then assumed that the interaction of the above described (1) to (4) will achieve a remarkable effect of improving steering stability during high-speed running.

[0012] It is preferred that the rubber composition includes carbon black and that the carbon black content, based on 100 parts by mass of the rubber component in the rubber composition, is greater than 1 part by mass and less than 25 parts by mass.

[0013] If the carbon black content is within the range described above, the silicon dioxide content can be increased, making it easier to achieve the polymer chain strengthening effect of silicon dioxide, thus further improving steering stability during high-speed operation.

[0014] The rubber composition preferably has a rubber hardness greater than 50 and less than 80. If the rubber hardness is within the range described above, it is assumed that steering stability during high-speed operation will be further improved.

[0015] It is preferred that the tread section has one or more lateral grooves extending in the direction of the tire width, and that the total volume of the one or more lateral grooves is 2.0% or more and 5.0% or less of the volume of the tread section. This suppresses movement of the tread section, and it is assumed that steering stability during high-speed driving is further improved.

[0016] It is preferred that the tread section has one or more circumferential grooves extending in a tire circumferential direction, and wherein one of the one or more circumferential grooves has a ratio (L 80 / L0) of a groove width L 80At an 80% position, the groove depth of the deepest section of the circumferential groove corresponds to a groove width L0 at the ground contact surface of the tread section of 0.3 or more and 0.7 or less. Movement of the entire rib section on the ground surface of the rib section of the tread section can thereby be suppressed, so that steering stability during high-speed running is assumed to be further improved.

[0017] It is preferred that the tread section has a groove inclined in a tire circumferential direction or a tire width direction, and that a maximum width L of the groove inclined in the tire circumferential direction or the tire width direction is greater than 7.0 mm and less than 20.0 mm.

[0018] By providing the tread section with the groove that is inclined in the tire circumference or width direction, responsiveness can be improved, while the tracking ability of the ground contact area of ​​the tread section to the road surface is improved, so that steering stability during high-speed driving is assumed to be further improved.

[0019] It is preferred that T is greater than 6.0 mm and less than 12.0 mm. If the thickness of the tread section is within the range described above, responsiveness can be improved, while the tracking ability of the tread-ground contact area with the road surface is enhanced, so that steering stability during high-speed driving is expected to be further improved. <definitionen>

[0020] A "standardized condition" is a state in which a tire is mounted on a standardized rim, inflated to a standardized pressure, and unloaded. Unless otherwise specified, a tire is used in this standardized condition.

[0021] Unless otherwise specified, a “dimension of each part of the tire” is a value specified in a standardized state for one appearing on the outer surface of the tire, while for one present inside the tire, or for one on a tire cut surface, it is a value specified in a state in which, for example, the tire is cut along a plane containing a tire axis of rotation and the cut piece of tire is held to a rim width of a standardized rim.

[0022] A "standardized rim" is a rim within a standard system that includes a standard on which the tire is based, and which is defined by the standard for each tire. For example, "standardized rim" refers to a standard rim of an applicable size described in the "JATMA YEAR BOOK" published by JATMA (The Japan Automobile Tire Manufacturers Association, Inc.), a "Measuring Rim" described in the "STANDARDS MANUAL" published by ETRTO (The European Tyre and Rim Technical Organisation), or a "Design Rim" described in the "YEAR BOOK" published by TRA (The Tire and Rim Association, Inc.), referenced in that order, and if an applicable size exists at the time of reference, the rim conforms to its standard.Furthermore, in the case of tires not defined by the standard, the standardized rim shall refer to a rim that can be fitted to the tire and whose width is the narrowest among rims that have the smallest diameter capable of maintaining internal pressure (i.e., causing no air leakage between the rim and the tire).

[0023] A “standardized internal pressure” is an air pressure in a standard system containing a standard on which the tire is based, defined by the standard for each tire. It refers, for example, to a “MAXIMUM AIR PRESSURE” in JATMA, “INFLATION PRESSURE” in ETRTO, or a maximum value described in the “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” table in TRA, to which reference is made in that order, as in the case of the standardized rim, and if there is an applicable size at the time of reference, the standardized internal pressure conforms to its standard.Furthermore, in the case of tires not defined by the standard, the standardized internal pressure shall refer to a standardized internal pressure (250 kPa or more) of another tire size (specified in the standard) for which the standardized rim is described as a standard rim, and if several standardized internal pressures of 250 kPa or more are described, it shall refer to a minimum value below that.

[0024] A "standardized load in kg" is a load within a standard system that includes a standard on which the tire is based. This standard is defined by the standard for each tire, for example, a "MAXIMUM LOAD CAPACITY" for JATMA, a "LOAD CAPACITY" for ETRTO, or a maximum value described in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table for TRA. Reference is made to this standard in that order, as in cases of a standardized rim and standardized inflation pressure. If an applicable size exists at the time of reference, the load conforms to its standard. Then, in the case of a tire not specified in the standard described above, the separately calculated maximum load capacity W is used. L defined as a standardized load.

[0025] The "maximum load capacity W" L The load capacity in kg is calculated using the following equations, where "V" is a virtual volume in mm³ of a tire, "Dt" is a tire outer diameter in mm in a standardized state, "Ht" is a tire cross-sectional height in mm in a tire radial direction in a cross-section of the tire in a plane containing a tire axis of rotation, and "Wt" is a tire cross-sectional width in mm in a standardized state. If R represents a rim diameter of the tire, Ht can be calculated as (Dt-R) / 2. Wt is a value obtained by excluding any patterns or markings on the sidewall of the tire, if present. Furthermore, the "maximum load capacity" has the same meaning as the standardized load described above. WL=0.000011×V+175 V={(Dt / 2)2−(Dt / 2−Ht)2}×π×Wt

[0026] A "thickness T in mm of a tread section" is the thickness of the entire tread section as measured along a normal to a tread-ground contact area on a tire equator in a cross-section passing through a tire axis of rotation. In a case where a circumferential groove is present on a tire equator, the thickness T is the thickness measured along a normal to a tread-ground contact area on a central section in one tire width direction of a rib section, where the central section is closest in the tire width direction of the rib section to a tire equator plane, of rib sections present on both side faces in one tire width direction of the groove.

[0027] A "groove" refers to a recessed section formed on a tire tread, specifically one with an opening width of 2.0 mm or more at the tread-ground contact surface of the groove. A recessed section with an opening width of less than 2.0 mm at the tread-ground contact surface is referred to as a "sipe."

[0028] A "circumferential groove" refers to a groove that extends in one direction around the circumference of the tire. The circumferential groove can extend linearly along the circumference or it can extend in a wavy, sinusoidal, or zigzag pattern along the circumference.

[0029] A "groove depth" refers to the maximum value of the distance between a straight line connecting the ends of the groove on a tread-ground contact patch and the deepest section of the groove in a tire radial direction. In cases where the groove depth varies in a tire width direction or circumferential direction, this maximum value is defined as the groove depth. Furthermore, the depth at any point of triple or multiple intersection where several grooves intersect is excluded from the groove depth.

[0030] A "side groove" refers to a groove that extends in one direction of the tire's width. Here, "extends in one direction of the tire's width" means that the angle formed by a line segment connecting the start and end points and the tire's width direction is less than 45°. If the groove extends to a tread end, the tread end should be the start or end point. A "side groove volume" is a value of volume defined by an area connecting the ends of the side groove in one direction of the tire's width and a groove wall, for a tire in a standardized condition. A "total side groove volume" can be calculated by determining the volumes of individual side grooves.

[0031] A "volume of a tread section" refers to the volume of the tread section assuming that all grooves of the tread section are filled. The "tread section" here is a section that forms a contact patch of a tire, and in a case where the tire includes an element forming a tire skeleton of steel or textile material, such as a belt ply, a belt reinforcement ply, a carcass ply, and the like, in a cross-section in a tire radial direction, an element on an outside of it in the tire radial direction.

[0032] A "groove width L0 of a circumferential groove on a ground contact surface of a tread section" is the width in mm of the circumferential groove on a tread-ground contact surface in a tire rotation axis direction, measured in a standardized condition. A "groove width L 80 "at 80% position of the deepest section of a circumferential groove" is a width in mm at the 80% position of the deepest section of the circumferential groove in a tire rotation axis direction, measured in a standardized condition.

[0033] A “groove depth of the deepest section of a circumferential groove” is a groove depth of a circumferential groove with the deepest groove depth when multiple circumferential grooves are present.

[0034] A "maximum width of an inclined groove" refers to the maximum width among the opening widths of grooves on a tread-ground contact patch in a cross-section perpendicular to a centerline from both ends of a tread, extending in a groove extension direction. An opening width is the distance from one tread end to the other on the tread-ground contact patch. Here, a "groove extension direction" refers to a direction in which the groove extends continuously, for example, in the case of a circumferential groove, a circumferential direction, and in the case of a groove inclined in a tire width direction, a direction along the inclination in the tire width direction.

[0035] A “styrene content in mass % of a rubber component” is obtained by multiplying the styrene content of each rubber that makes up the entire rubber component in 100 mass % by its content that is present in the entire rubber component, and adding all of them together.

[0036] A “vinyl content in mass % of a rubber component” is obtained by multiplying a content of vinyl butadiene unit derived from 1,2-butadiene bond of each rubber forming the entire rubber component in 100 mass % by its content present in the entire rubber component and adding all of them together.

[0037] A “rubber component of a rubber composition” is a component that contributes to crosslinking in the rubber composition and generally has a weight-average molecular weight (Mw) of 10,000 or more. <messverfahren>

[0038] "30 °CE* at a dynamic strain of 0.25%" is a complex modulus of elasticity measured using a viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 0.25%, and a specific strain mode. When a sample for measuring the complex modulus of elasticity is produced by cutting it from a tire, it is cut from a tread section of the tire such that one of the tire's radial directions becomes the thickness direction.

[0039] "30 °CE* at a dynamic strain of 1.0%" is a complex elastic modulus measured using a viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 1.0%, and a specific strain mode. A sample for measurement is prepared in a similar manner to the case for 30 °CE* at a dynamic strain of 0.25%.

[0040] “30 °C-ΔE* (0.25 % -1.0 %)” can be determined from a difference between 30 °CE* at a dynamic strain of 0.25 % and 30 °CE* at a dynamic strain of 1.0 %.

[0041] A “rubber hardness” is a value obtained by cutting out a tread section from a tread section forming a ground contact area, such that a tire radial direction becomes a thickness direction, to produce a sample for measuring hardness, and by pressing a Type A hardness tester against the sample from the ground contact area side at 23 °C in accordance with JIS K 6253.

[0042] The glass transition temperature (Tg) of a rubber component is measured by measuring the temperature while increasing at a rate of 10 °C / min using a differential scanning calorimeter (Q200) manufactured by TA Instruments Japan Inc. in accordance with JIS K 7121.

[0043] An "average primary particle size" is calculated as the arithmetic mean of the particle sizes of 400 particles photographed with a transmission or scanning electron microscope. Regarding particle size, in cases where the particle is substantially circular, the diameter of the circle is defined as the particle size; in cases where it is needle- or rod-shaped, a minor axis is defined as the particle size; and in other cases, an equivalent circular diameter calculated from an electron micrograph is defined as the particle size. The equivalent circular diameter is calculated as the positive square root of 4 × (particle area) / π. The average primary particle size is applied to silicon dioxide, carbon black, etc.

[0044] A “specific nitrogen adsorption surface (N2SA) of soot” is measured according to JIS K 6217-2:2017.

[0045] A “specific nitrogen adsorption surface (N2SA) of silicon dioxide” is measured by the BET method according to ASTM D3037-93.

[0046] A "styrene content" is a value determined by 1 A “cis content (cis-1,4-bonded butadiene unit quantity)” is calculated by infrared absorption spectrometry according to JIS K 6239-2:2017 and is applied, for example, to a rubber component with a repeating unit derived from butadiene, such as an SBR and the like.

[0047] A “softening point of a resin component” is specified as a temperature at which a ball falls when the softening point defined in JIS K 6220-1:2015 7.7 is measured using a ring-and-ball softening point measuring device.

[0048] A “plasticizer content” also includes any amount of a plasticizer contained in a stretched rubber component that was previously stretched with the plasticizer, such as oil, a resin component, a liquid rubber component, and the like. The same applies, for example, to an oil content, a resin component content, and a liquid rubber content; and, for instance, a stretching oil is included in the oil content if a stretching component is oil.

[0049] A process for producing a pneumatic tire, which is an embodiment of the present invention, is described in detail below. However, the following descriptions are for illustrative purposes only and are not intended to limit the technical scope of the present invention to this description. Furthermore, in this description, a numerical range identified as "to" means that it contains the numerical values ​​from both ends. <reifen>

[0050] Fig. Figure 1 is a schematic view of a ground contact area when a tread section of a tire, which is an embodiment of the present invention, is pressed against a flat surface. A tread section 10 has several circumferential grooves 1. In Fig. 1 Three circumferential grooves 1 are provided, although the number of circumferential grooves is not particularly limited and may, for example, be two to five.

[0051] The tread section 10 has rib sections 2 separated by several circumferential grooves 1 in a tire width direction W. A shoulder rib section 11 is a pair of rib sections formed between the circumferential groove 1 and the tread end Te. A center rib section 12 is a rib section formed between a pair of shoulder rib sections 11. Fig. 1 Two middle pier sections 12 are provided, although the number of middle pier sections is not particularly limited and can be, for example, one to five.

[0052] Fig. Figure 2 shows a schematic unfolded view of a tread section of a tire, which is a further embodiment of the present invention. Fig. 2 The tread section 10 has several zigzag-shaped circumferential grooves 1 that extend continuously in a circumferential direction. A lateral groove 5 is inclined such that, while moving towards a central section in a tire width direction, it shifts to one side. The lateral groove 5 then extends over the circumferential groove 1 at a curved section of the circumferential groove 1. Furthermore, the shoulder rib section 11 is provided with several linear shoulder sipes 22, each having an end open towards the circumferential groove 1, and the central rib section 12 is provided with several linear central sipes 23, each having an end open towards the circumferential groove 1. In addition, in the present embodiment, the circumferential grooves 1 need not necessarily be continuous in the circumferential direction without interruption and may be subdivided by the lateral grooves 5.

[0053] The tread section according to the present embodiment preferably has one or more lateral grooves to improve steering stability during high-speed driving. The total volume of the one or more lateral grooves is preferably 1.5% or more, more preferably 2.0% or more, and even more preferably 2.5% or more of the volume of the tread section. Furthermore, the total volume of the one or more lateral grooves is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 5.0% or less of the volume of the tread section. If the total volume of the lateral grooves is within the ranges described above relative to the volume of the tread section, it is assumed that steering stability during high-speed driving is further improved.

[0054] The maximum width L of the groove inclined in the direction of the tire circumference or tire width is, from the perspective of steering stability during high-speed driving, preferably greater than 7.0 mm, more preferably greater than 8.0 mm, and even more preferably greater than 9.0 mm. On the other hand, an upper limit of the maximum width L is preferably less than 20.0 mm and more preferably less than 15.0 mm, but is not particularly restricted.

[0055] Fig. Figure 3 is a cross-sectional view passing through a tire rotation axis of a tire according to the present embodiment and showing a portion of the tread section. Fig. 3 the tread section consists of a first layer 3 and a second layer 4, but it is not limited to such an aspect, and the tread section may, for example, be a single rubber layer or may be three or more rubber layers.

[0056] The thickness T of the tread section of the pneumatic tire according to the present embodiment is preferably greater than 6.0 mm, more preferably greater than 8.0 mm, still more preferably 10.0 mm or more, and still more preferably 12.0 mm or more. Furthermore, the thickness T of the tread section is preferably 18.0 mm or less, more preferably 15.0 mm or less, and still more preferably 14.0 mm or less.

[0057] From the perspective of steering stability during high-speed driving, it is preferred that a groove width of any one of the circumferential grooves of the tread section according to the present embodiment be narrower on an inner side in a tire radial direction than a groove width on a ground contact surface 6 of the tread section. The ratio (L 80 / L0) of the groove width L 80 The ratio of the groove depth of the deepest section of the circumferential groove to the groove width L0 of the circumferential groove, which is narrower on the inside in the tire radial direction than the groove width at the ground contact surface 6 of the tread section, is preferably 0.20 or more, more preferably 0.30 or more, and still more preferably 0.40 or more. Furthermore, L 80 / L0 preferably 0.80 or less, further preferred 0.70 or less and still further preferred 0.60 or less.

[0058] The 30°CE* at a dynamic elongation of ± 0.25% of the rubber composition forming the tread section according to the present embodiment is preferably 19.0 MPa or more, more preferably 20.0 MPa or more, still more preferably 22.0 MPa or more, and still more preferably 23.0 MPa or more. Furthermore, the 30°CE* at a dynamic elongation of ± 0.25% is preferably 28.0 MPa or less, more preferably 26.0 MPa or less, and still more preferably 25.0 MPa or less.

[0059] The dynamic elongation of ± 1.0% of the rubber composition forming the tread section according to the present embodiment is preferably 13.0 MPa or more, more preferably 14.0 MPa or more, more preferably 15.0 MPa or more, and more preferably 16.0 MPa or more. Furthermore, the dynamic elongation of ± 1.0% of the rubber composition forming the tread section according to the present embodiment is preferably 20.0 MPa or less, more preferably 18.0 MPa or less, and more preferably 17.0 MPa or less.

[0060] The 30 °C ΔE* (0.25% - 1.0%) of the rubber composition forming the tread section according to the present embodiment is 6.0 MPa or more, preferably 6.5 MPa or more, more preferably 6.8 MPa or more, more preferably 7.0 MPa or more, more preferably 7.2 MPa or more, more preferably 7.5 MPa or more, more preferably 7.8 MPa or more, and most preferably 8.0 MPa or more. Furthermore, an upper limit of the 30 °C ΔE* (0.25% - 1.0%) of the rubber composition forming the tread section according to the present embodiment is not particularly restricted, but may, for example, be 12.0 MPa or less, 10.0 MPa or less, 9.0 MPa or less, etc.

[0061] Furthermore, 30°CE* can be appropriately adjusted depending on the type and quantity of a rubber component, filler, softener, and the like, which will be described later. For example, 30°CE* can be increased by increasing the amount of filler, decreasing the amount of softener, or similar factors in the rubber composition.

[0062] The 30 °C-ΔE* (0.25% - 1.0%) / T of the rubber composition forming the tread section according to the present embodiment is 0.45 or more, preferably 0.50 or more, more preferably 0.60 or more, even more preferably 0.70 or more, and particularly preferably 0.75 or more. Furthermore, an upper limit of 30 °C-ΔE* (0.25% - 1.0%) / T is not particularly restricted, but may, for example, be 1.00 or less, 0.95 or less, 0.90 or less, etc.

[0063] The hardness of the rubber composition forming the tread section according to the present embodiment is, from the perspective of driving comfort, preferably greater than 50, more preferably greater than 55, and even more preferably greater than 60. Furthermore, from the perspective of steering stability, the hardness of the rubber is preferably less than 80, more preferably less than 75, and even more preferably less than 70.

[0064] Furthermore, the rubber hardness can be appropriately adjusted depending on the type and quantity of a rubber component, filler, softener, and the like, which will be described later. For example, the rubber hardness can be improved by increasing the amount of filler or by decreasing the amount of softener in the rubber composition.

[0065] The tread section of the present invention comprises at least one rubber layer. The rubber layer can be formed from a single rubber layer, preferably comprising a rubber layer that comes into contact with a road surface (a first layer) and a rubber layer that rests against a belt layer (a second layer) when the tire is in use, and can further comprise one or more rubber layers between the first layer and the second layer.

[0066] Any physical property value, such as 30 °C-ΔE* (0.25% - 1.0%) and the like, of the rubber composition forming the tread section, can, in a case where the tread section comprises two or more rubber layers, satisfy a physical property value in any of the rubber layers, preferably in the first layer. <kautschukkomponente>

[0067] The rubber composition forming the tread section according to the present embodiment (hereinafter referred to as the rubber composition according to the present embodiment, unless otherwise specified) comprises an isoprene-based rubber, preferably comprising an isoprene-based rubber and a butadiene rubber (BR), and further preferably comprising an isoprene-based rubber, a BR, and a styrene-butadiene rubber (SBR) as rubber components. It may also include other rubber components besides those listed above. Furthermore, the rubber component may be a rubber component consisting of an isoprene-based rubber, a BR, and an SBR. (Isoprene-based rubber)

[0068] Isoprene-based rubbers can include those commonly used in the tire industry, such as isoprene rubber (IR), natural rubber, and the like. Examples of natural rubber include unreformed natural rubber (NR), as well as refined natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), ultrapure natural rubber, grafted natural rubber, and the like. These isoprene-based rubbers can be used individually, or two or more can be used in combination.

[0069] An NR is not particularly restricted, and those commonly used in the tire industry can be used, examples of which include SIR20, RSS#3, TSR20 and the like.

[0070] For the purposes of the effects of the present invention, the isoprene-based rubber content in the rubber component is more than 40% by weight, preferably 45% by weight or more, more preferably 48% by weight or more, and even more preferably 50% by weight or more. On the other hand, the isoprene-based rubber content in the rubber component is preferably 90% by weight or less, more preferably 85% by weight or less, even more preferably 80% by weight or less, and particularly preferably 70% by weight or less. (BR)

[0071] A rubber (BR) is not particularly restricted, and those commonly used in the tire industry can be employed, such as a BR with a cis content of less than 50 mol% (a cis-poor BR), a BR with a cis content of 90 mol% or more (a cis-rich BR), a rare-earth-based butadiene rubber synthesized using a rare-earth-based catalyst (a rare-earth-based BR), a BR containing a syndiotactic polybutadiene crystal (an SPB-containing BR), a modified BR (a cis-rich modified BR, a cis-poor modified BR), and the like. These BRs can be used individually, or two or more of them can be used in combination.

[0072] For example, cis-rich BRs commercially available from Zeon Corporation, UBE Corporation, JSR Corporation, etc., can be used. When the cis-rich BR is used, low-temperature properties and abrasion resistance can be improved. The cis content of the cis-rich BR is preferably 95 mol% or more, more preferably 96 mol% or more, and even more preferably 97 mol% or more. Furthermore, the cis content of the BR is measured using the measurement method described above.

[0073] From the perspective of the effects of the present invention, the content of a BR, when combined, in the rubber component is preferably 5 wt% or more, more preferably 10 wt% or more, and even more preferably 15 wt% or more. On the other hand, the content of the BR, when combined, in the rubber component is preferably 60 wt% or less, more preferably 50 wt% or less, even more preferably 40 wt% or less, even more preferably 30 wt% or less, and particularly preferably 20 wt% or less. (SBR)

[0074] An SBR is not particularly restricted; examples include a solution-polymerized SBR (S-SBR), an emulsion-polymerized SBR (E-SBR), modified SBRs (a modified S-SBR, a modified E-SBR), and the like. Examples of modified SBRs include an SBR modified at its end and / or main chain, a modified SBR coupled with tin, a silicon compound, etc. (a modified SBR of condensate or with a branched structure, etc.), and the like. Among these, an S-SBR and a modified SBR are preferred. Furthermore, hydrogenated versions of these SBRs (hydrogenated SBRs) and the like may also be used. These SBRs may be used individually, or two or more of them may be used in combination.

[0075] The styrene content of an SBR is preferably 70 wt% or less, more preferably 60 wt% or less, even more preferably 50 wt% or less, and particularly preferably 45 wt% or less. Furthermore, the styrene content of the SBR is preferably 15 wt% or more, more preferably 20 wt% or more, even more preferably 25 wt% or more, particularly preferably 30 wt% or more, and particularly preferably 35 wt% or more. The styrene content of the SBR is also measured using the measurement method described above.

[0076] For abrasion resistance purposes, the glass transition temperature (Tg) of an SBR is preferably -60 °C or higher, more preferably -50 °C or higher, and even more preferably -40 °C or higher. Furthermore, the Tg of the SBR is preferably -20 °C or lower, more preferably -25 °C or lower, and even more preferably -30 °C or lower.

[0077] The content of an SBR, when combined, in the rubber component is preferably 10 wt% or more, further preferably 20 wt% or more, even more preferably 30 wt% or more, and particularly preferably 32 wt% or more. On the other hand, the content of the SBR in the rubber component is preferably 60 wt% or less, further preferably 50 wt% or less, even more preferably 40 wt% or less, even more preferably 35 wt% or less, and particularly preferably 30 wt% or less. (Other rubber components)

[0078] The rubber component may also comprise other rubber components than those described above, as long as the effects of the present invention are not impaired. Examples include, for instance, non-diene-based rubbers such as hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), halogenated butyl rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, and the like. (Rubber component synthesized from recycled / biomass-derived raw material)

[0079] A monomer that is a structural unit of a synthetic rubber, such as SBR, BR, and the like, can be derived from underground resources, such as petroleum, natural gas, and the like, or recycled from a rubber product, such as a tire, and the like, or from a non-rubber product, such as polystyrene, and the like. A monomer obtained through recycling (recycled monomer) is not particularly restricted; examples include recycled polyisoprene, recycled butadiene, recycled aromatic vinyl compounds, and the like. Examples of butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The aromatic vinyl compound described above is not particularly restricted, and examples include styrene and the like.Among these, recycled polyisoprene (a recycled polyisoprene), recycled butadiene (a recycled butadiene) and / or recycled styrene (a recycled styrene) are preferably used as a raw material.

[0080] A process for producing a recycled monomer is not particularly restricted; examples include, for instance, a process for synthesizing a monomer from a recycled naphtha obtained by decomposing a rubber product, such as a tire, etc. Furthermore, a process for producing a recycled naphtha is not particularly restricted and can, for example, be obtained by decomposing a rubber product, such as a tire, etc., under high temperature and high pressure, by decomposing it using microwaves, or by extruding it after mechanical pulverization.

[0081] Furthermore, a monomer that is a structural unit of a polymer, such as an IR, an SBR, a BR, and the like, can be a biomass-derived monomer. In this description, biomass refers to material derived from natural sources, such as plants and the like. Biomass is not particularly restricted; examples include agricultural, forestry, and fishery products, sugar, wood waste, plant residues after the capture of a useful component, plant-derived ethanol, biomass naphtha, and the like.

[0082] The biomass-derived monomer (biomass monomer) is not particularly restricted; examples include biomass-derived butadiene, biomass-derived aromatic vinyl compounds, and the like. Examples of butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The aromatic vinyl compound described above is not particularly restricted, and examples include styrene and the like. Furthermore, the method of producing a biomass monomer is not particularly restricted; examples include, for instance, one through biological and / or chemical and / or physical transformation of animals and plants, and the like.Microbial fermentation is representative of biological conversion, and examples of chemical and / or physical conversion include conversion due to a catalyst, conversion due to high heat, conversion due to high pressure, conversion due to an electromagnetic wave, conversion due to a critical fluid, and combinations thereof.

[0083] A polymer synthesized from a biomass monomer component (biomass polymer) is not particularly restricted; examples include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or a biomass-derived aromatic vinyl compound, and the like. Examples of aromatic vinyl butadiene copolymer include, for instance, styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene, and the like.

[0084] Whether a polymer raw material is derived from biomass can be determined by pMC (percent modern carbon), measured according to ASTM D 6866-10. Here, pMC is a ratio of 14 C concentration of a sample to 14 The carbon concentration of a modern standard carbon is used as an index to represent the biomass ratio of a compound (rubber). The meaning of this value is explained below.

[0085] In 1 mol of carbon atoms (6.02 × 10 23 (Pieces) are approximately 6.02 × 10 11 14 C are present, which are about one trillionth the number of normal carbon atoms. A half-life of 14 C is 5730 years, and 14 Carbon dioxide (C) decreases regularly. Therefore, in the case of fossil fuels such as coal, oil, natural gas, and the like, where it is assumed that 226,000 years or more have passed since carbon dioxide was absorbed by plants in the atmosphere to be stored, all the carbon dioxide is decaying. 14 Carbon elements, which were present at the beginning of the fixation. Therefore, fossil fuels, such as coal, petroleum, natural gas and the like, do not contain any carbon in the current 21st century. 14 Carbon element. Therefore, chemical substances produced using these fossil fuels as raw materials also contain no carbon. 14 C-element.

[0086] on the other hand 14 C is constantly produced by cosmic rays that cause nuclear reactions in the atmosphere. Thus, a decrease of 14 C due to radioactive decay and the production of 14 C is balanced due to nuclear reactions and is the amount of 14 The temperature C in the Earth's atmospheric environment is constant. Therefore, the 14 Carbon concentration of substances derived from biomass resources circulating in the current environment, a value of approximately 1 × 10 -12 Molar percentages are based on total carbon atoms, as described above. Accordingly, by using the difference between these values, a biomass ratio in a given compound can be calculated.

[0087] This 14 C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, a 13 C concentration ( 13 C / 12 C) and a 14 C concentration ( 14 C / 12 C) measured. During the measurements, a 14 Carbon concentration in a circulating carbon in nature from 1950 as reference standards for the 14 C concentration is used. A standard oxalic acid body provided by the National Institute of Standards and Technology (NIST) is used as a specific reference material. A specific radioactivity of carbon in this oxalic acid (radioactivity intensity of 14 C per gram of carbon) is sorted for each carbon isotope. 13 C is corrected to a constant value, and a value corrected for attenuation from 1950 to the measurement date is considered a standard. 14 A carbon concentration value (100%) is used. A ratio of this value to an actual measured value for a sample is called a pMC value.

[0088] Thus, when a rubber is produced from a material derived 100% from biomass, the 14 The carbon concentration typically has a value of approximately 110 pMC; currently, under normal conditions, it often does not reach 100, although there are regional differences and the like. On the other hand, it shows that when this 14 When the carbon concentration of a chemical substance derived from a fossil fuel, such as petroleum, is measured, it will be approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%, as mentioned above.

[0089] Based on the above, it is suitable in terms of environmental protection to use a material, such as a rubber with a high pMC value, and the like, that is, a material such as a rubber with a high biomass ratio, and the like, for a rubber composition. <Füllstoff>

[0090] The rubber composition according to the present embodiment comprises silicon dioxide as a filler and preferably comprises silicon dioxide and carbon black. (Silicon dioxide)

[0091] Silicon dioxide is not particularly restricted, and those commonly used in the tire industry can be employed, such as silicon dioxide produced by a dry process (anhydrous silicon dioxide), silicon dioxide produced by a wet process (hydrous silicon dioxide), and the like. The source of silicon dioxide is not particularly restricted and can be, for example, a mineral-derived raw material, such as quartz, a biomaterial-derived raw material, such as rice husks (e.g., silicon dioxide produced from a biomass material, such as rice husks), or silicon dioxide recycled from a silicon dioxide-containing product. Among these, hydrous silicon dioxide produced by a wet process is preferred because it contains many silanol groups.This silicon dioxide can be used alone, or two or more of them can be used in combination.

[0092] A specific nitrogen adsorption surface area (N2SA) of silicon dioxide is preferably 100 m² to ensure reinforcement properties and adhesion performance. 2 / g or more, preferably 120 m 2 / g or more, preferably 140 m 2 / g or more, preferably 160 m 2 / g or more and especially preferably 180 m 2 / g or more. Furthermore, from the perspective of heat generation and processability, it is preferably 350 m³. 2 / g or less, preferably 300 m 2 / g or less and preferably 250 m 2 / g or less. Furthermore, the N2SA of silicon dioxide is measured using the measurement method described above.

[0093] Silicon dioxide from a biomass material can be obtained, for example, by burning rice husks to obtain rice husk ash, extracting silicate from the rice husk ash using a sodium hydroxide solution, producing silicon dioxide by reacting the silicate with sulfuric acid in the same way as for conventional wet silicon dioxide, and filtering, washing with water, drying, and pulverizing the silicon dioxide precipitates.

[0094] Silicon dioxide recycled from a product containing silicon dioxide can, for example, be recovered from an electronic component such as a semiconductor, a tire, a product containing silicon dioxide such as a desiccant, a filter material such as diatomaceous earth, etc. Furthermore, the recovery method is not particularly restricted; examples include pyrolysis, decomposition by electromagnetic waves, and the like. Silicon dioxide recovered from an electronic component such as a semiconductor or from a tire is preferred.

[0095] When silicon dioxide crystallizes, it is insoluble in water, and silicic acid, a component of it, cannot be used. Crystallization of silicon dioxide in rice hull ash can be suppressed by controlling the firing temperature and duration (JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222, etc.). Amorphous silicon dioxide extracted from rice hulls, such as that commercially available from Wilmar, etc., can be used.

[0096] The average primary particle size of silicon dioxide is preferably 10 nm or more, more preferably 12 nm or more, and even more preferably 14 nm or more. Furthermore, the average primary particle size is preferably 22 nm or less, more preferably 20 nm or less, and even more preferably 18 nm or less. The average primary particle size of silicon dioxide is also measured using the measurement method described above.

[0097] From the perspective of the effects of the present invention, the silicon dioxide content based on 100 parts by mass of the rubber component is preferably more than 30 parts by mass, more preferably more than 40 parts by mass, even more preferably more than 50 parts by mass, even more preferably more than 60 parts by mass, even more preferably more than 70 parts by mass, even more preferably more than 80 parts by mass, and particularly preferably more than 90 parts by mass. Furthermore, from the perspective of fuel efficiency, it is preferably less than 150 parts by mass, more preferably less than 130 parts by mass, even more preferably less than 120 parts by mass, and particularly preferably less than 110 parts by mass. (Soot)

[0098] Examples of carbon black include, but are not limited to, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, and the like. A raw material for carbon black can be a biomass material, such as lignin, vegetable oil, and the like, or it can be pyrolysis oil obtained by pyrolyzing a used tire. Furthermore, a method of producing carbon black can be one by combustion, such as in a furnace process, and the like; one by hydrothermal carbonization (HTC); or one by pyrolysis of methane, such as a thermal carbon black process, and the like. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan KK, Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, NIPPON STEEL Carbon Co. Ltd., Columbia Chemical Corporation, etc.These soots can be used alone, or two or more of them can be used in combination.

[0099] In addition to the soot described above, from the point of view of life cycle assessment, soot from a biomass material, such as lignin, and the like, or recovered soot obtained by pyrolysis and refining of a product containing soot, such as a tire, and the like, can be used as soot.

[0100] In this description, "recovered carbon black" refers to carbon black obtained by pulverizing a product such as a used tire containing carbon black and the like, and burning the pulverized product. When the product is subjected to oxidative combustion by heating in air using a thermal weight measurement method in accordance with JIS K 6226-2:2003, the ratio of mass to ash (ash content), which is a non-combustible component, is 13% by mass or more. That is, the ratio of mass (amount of carbon) to weight loss due to the oxidative combustion of the recovered carbon black is 87% by mass or less. The recovered carbon black can be expressed as rCB.

[0101] The recovered carbon black can be obtained from a pyrolysis process of a used pneumatic tire. EP3427975 A, for example, describes, with reference to "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408 to 449 (2012), in particular pages 438, 440 and 442, that the recovered carbon black can be obtained by pyrolysis of an organic material at 550 to 800 °C in the absence of oxygen or by vacuum pyrolysis at a relatively low temperature (

[0027] ). As mentioned in

[0004] of JP6856781 B (A comparison of surface morphology and chemistry of pyrolytic carbon blacks with commercial carbon blacks, Powder Technology 160 (2005), pages 190-193), such carbon black obtained by the pyrolysis process typically lacks a functional group on its surface.

[0102] The recovered carbon black may lack a functional group on its surface, or it may be treated so that its surface includes a functional group. The treatment, which is carried out so that the surface of the recovered carbon black includes a functional group, can be implemented by a conventional method. For example, in EP3173251 A, carbon black comprising a hydroxyl and / or carboxyl group on its surface is obtained by treating carbon black obtained from a pyrolysis process with potassium permanganate under acidic conditions. Furthermore, in JP6856781 B, carbon black with an activated surface is obtained by treating carbon black obtained from a pyrolysis process with an amino acid compound comprising at least one thiol or disulfide group. The recovered carbon black according to the present embodiment also includes carbon black whose surface has been treated to include a functional group.

[0103] The recovered carbon black can be that which is commercially available from Strebl Green Carbon Pte Ltd., LDC Co., Ltd. etc.

[0104] An average primary particle size of carbon black is preferably 12 nm or more, more preferably 15 nm or more, even more preferably 18 nm or more, and particularly preferably 20 nm or more. On the other hand, from the perspective of obtaining reinforcing properties, the average primary particle size is preferably 80 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. Furthermore, the average primary particle size of carbon black is measured by the measurement method described above.

[0105] A specific nitrogen adsorption surface area (N2SA) of soot is preferably 200 m² from the point of view of the effects of the present invention. 2 / g or less, preferably 180 m 2 / g or less and preferably 150 m 2 / g or less. Furthermore, N2SA is preferably 100 m. 2 / g or larger, preferably 120 m 2 / g or larger and preferably 130 m 2 / g or greater. Furthermore, the N2SA of soot is measured using the measurement method described above.

[0106] When combined, the carbon black content, based on 100 parts by mass of the rubber component, is, from the perspective of the effects of the present invention, preferably more than 1 part by mass, more preferably more than 3 parts by mass, even more preferably more than 5 parts by mass, even more preferably more than 9 parts by mass, and particularly preferably more than 15 parts by mass. Furthermore, from the perspective of maintaining flexibility to mitigate stress, it is preferably less than 80 parts by mass, more preferably less than 60 parts by mass, even more preferably less than 40 parts by mass, even more preferably less than 30 parts by mass, even more preferably less than 25 parts by mass, and particularly preferably 20 parts by mass or less. (Other fillers)

[0107] The rubber composition may include fillers other than silicon dioxide and carbon black. Other fillers are not particularly restricted, and those that are conventionally and commonly used in the tire industry, such as aluminum hydroxide, calcium carbonate, alumina, clay, talc, and the like, may be combined. <silankupplungsmittel>

[0108] Silicon dioxide is preferably used in combination with a silane coupling agent. Examples of silane coupling agents include, for example, sulfide-based silane coupling agents, such as bis(3-triethoxysilylpropyl)disulfide, bis(3-triethoxysilylpropyl)tetrasulfide, and the like; mercapto-based silane coupling agents, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like; vinyl-based silane coupling agents, such as vinyltriethoxysilane, vinyltrimethoxysilane, and the like; and amino-based silane coupling agents, such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and the like. Glycidoxy-based silane coupling agents, such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and the like;Nitro-based silane coupling agents, such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and the like; chlorine-based silane coupling agents, such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxy, and the like, are acceptable, but not specifically limited to these. Sulfide-based and / or mercapto-based silane coupling agents are preferred. Examples of silane coupling agents that can be used include those commercially available from Evonik Industries AG, Momentive Performance Materials, etc. These silane coupling agents can be used individually, or two or more can be used in combination.

[0109] The content of a silane coupling agent based on 100 parts by mass of the rubber component (a total amount of several silane coupling agents when used in combination) is, from the perspective of enhancing the dispersibility of silicon dioxide, preferably more than 3.0 parts by mass, further preferably more than 5.0 parts by mass, and even more preferably more than 6.0 parts by mass. Furthermore, from the perspective of preventing deterioration of abrasion resistance, it is preferably less than 15 parts by mass, further preferably less than 10 parts by mass, and even more preferably less than 8.0 parts by mass. (Other connecting means)

[0110] The rubber composition may, in addition to rubber components and fillers, appropriately include bonding agents that are conventionally and commonly used in the tire industry, for example a softening agent, processing aid, vulcanized rubber particles, wax, stearic acid, zinc oxide, an antioxidant, a vulcanizing agent, a vulcanization accelerator and the like. <weichmittel>

[0111] A plasticizer is a material that imparts plasticity to a rubber component and is conceptually a plasticizer that is both liquid at 25°C and solid at 25°C. Examples of plasticizers include resin, oil, liquid rubber, ester-based plasticizers, and the like. These plasticizers can be derived from mineral resources such as petroleum, natural gas, and the like, or they can be derived from biomass. Additionally, a low-molecular-weight hydrocarbon component obtained by pyrolysis and extraction from a used tire or a product comprising various components can be used as a plasticizer. The plasticizer can be used alone, or two or more can be used in combination. (Oil)

[0112] Examples of oils include mineral oil, vegetable oil, animal oil, and the like. Furthermore, from a life cycle assessment perspective, oils obtained by cleaning used oil after use in a rubber mixer or engine, or used cooking oil from a restaurant, can be used. Oils can be used alone, or two or more can be used in combination.

[0113] In this description, a mineral oil refers to oil derived from mineral resources such as petroleum, natural gas, and the like. Examples of mineral oil include paraffinic oils (mineral oils), naphthenic oils, aromatic oils, and the like. Specific examples of mineral oil include, for example, Mild Extract Solvate (MES), Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Treated Residual Aromatic Extract (TRAE), Residual Aromatic Extract (RAE), and the like. Furthermore, as an environmental measure, an oil with a low content of polycyclic aromatic compounds (PCAs) may also be used. Examples of oils with a low PCA content include MES, TDAE, heavy naphthenic oil, and the like.

[0114] In this description, examples of vegetable oil include, for instance, 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, Japan wax, and the like. Furthermore, examples of vegetable oil also include refined oils obtained by refining the oils described above (cooking oils, etc.).), a transesterified oil obtained by transesterifying the oil described above, a hydrogenated oil obtained by hydrogenating the oil described above, a thermally polymerized oil obtained by thermally polymerizing the oil described above, an oxidized polymerized oil obtained by oxidizing the oil described above, a used cooking oil obtained by restoring what was previously used as an edible oil, etc., and the like. Furthermore, the vegetable oil may be liquid or solid at 25 °C.

[0115] The vegetable oil according to the present embodiment preferably comprises acylglycerol and further preferably triacylglycerol. In this description, acylglycerol also refers to a compound in which a hydroxyl group of glycerol and a fatty acid are ester-bound. Acylglycerol is not particularly restricted and can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol can be a monomer, a dimer, or a multimer that is a trimer or higher. Acylglycerol that is a dimer or higher can also be obtained by thermal polymerization, oxidative polymerization, or the like. Finally, acylglycerol can be liquid or solid at 25 °C.

[0116] As a method of checking whether the rubber composition includes acylglycerol, the test can be carried out, but is not particularly limited to 1 H-NMR measurement. In particular, a rubber composition comprising triacylglycerol is immersed in a heavy chloroform at 25 °C for 24 hours and removed to 1 When measuring ¹H NMR at room temperature, and when a signal from tetramethylsilane (TMS) is set to 0.00 ppm, signals near 5.26 ppm, near 4.28 ppm, and near 4.15 ppm are observed, with the signals assumed to be derived from hydrogen atoms bonded to carbon atoms adjacent to oxygen atoms of an ester group. Furthermore, "near" in this paragraph refers to a range of ±0.10 ppm.

[0117] The fatty acid described above is not particularly restricted and can be either an unsaturated or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids, such as oleic acid, and the like, and polyunsaturated fatty acids, such as linoleic acid, linolenic acid, and the like. Furthermore, examples of saturated fatty acids include butyric acid, lauric acid, and the like.

[0118] The desired fatty acid is one with few double bonds, meaning a saturated or monounsaturated fatty acid, and oleic acid is preferred. A vegetable oil containing such a fatty acid can be, for example, a saturated or monounsaturated fatty acid, or it can be a vegetable oil modified by transesterification or similar processes. Furthermore, to produce a vegetable oil containing such a fatty acid, a plant can be improved through selective breeding, gene combination, or similar methods.

[0119] For example, vegetable oils that are commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo KK, ENEOS Corporation, Olisoy, H&R Group, Hokoku Corporation, Fuji Kosan Co., Ltd., The Nisshin OilliO Group, Ltd., etc., can be used.

[0120] Examples of animal oil include fish oil, beef tallow, oleyl alcohol derived from it, and the like.

[0121] The oil content, when combined, based on 100 parts by mass of the rubber component, is preferably 10 parts by mass or more, further preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more. Furthermore, the content is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and still more preferably 60 parts by mass or less. As described above, "oil content" also includes any amount of oil contained in an oil-enhanced rubber. (resin component)

[0122] The rubber composition according to the present embodiment may include a resin component. The resin component that may be used in the present embodiment is not particularly restricted, and any resin commonly used in the tire industry may be used. Examples include, for instance, a C9-based resin, a C5-based resin, a C5 / C9-based resin, a dicyclopentadiene-based resin, an aromatic vinyl-based resin, a coumaron-based resin, an indene-based resin, a terpene-based resin, a rosin-based resin, a phenol-based resin, and the like. These resin components may be used individually, or two or more of them may be used in combination. Each resin component may also be used individually, or two or more of them may be used in combination. <<Harz auf C9-Basis> >

[0123] A "C9-based resin" refers to a resin obtained by polymerizing C9 fractions and can be a polymer obtained by polymerizing a C9 fraction alone, or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. Furthermore, a C9-based resin can be one obtained by hydrogenating or modifying it. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumaron, indene, methylindene, dicyclopentadiene, and the like. Examples of C9-based resins include those commercially available from BASF, Zeon Corporation, ENEOS Corporation, etc. <<Harz auf C5-Basis> >

[0124] A "C5-based resin" refers to a resin obtained by polymerizing C5 fractions, and can be one obtained by hydrogenating or modifying them. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, piperylene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, and the like. Examples of C5-based resins that can be used include those commercially available from STRUKTOL, Zeon Corporation, ENEOS Corporation, etc. <<Harz auf C5 / C9-Basis> >

[0125] A "C5 / C9-based resin" refers to a resin obtained by copolymerizing the C5 and C9 fractions, and can be one obtained by hydrogenation or modification thereof. For example, suitable C5 / C9-based petroleum resins include those commercially available from Tosoh Corporation, Zibo Luhua Hongjin New Material Group Co., Ltd. <<Harz auf Dicyclopentadien-Basis> >

[0126] A "dicyclopentadiene-based resin" refers to a resin that contains cyclopentadiene (CPD) and / or dicyclopentadiene (DCPD) as the predominant monomer component and may be one obtained by hydrogenation or modification thereof. Examples of dicyclopentadiene-based resins include polymers obtained by polymerizing only dicyclopentadiene as a monomer, copolymers obtained by copolymerizing dicyclopentadiene with the C9 fraction (DCPD / C9 resin), and similar formulations. Examples of dicyclopentadiene-based resins that can be used include those commercially available from Exxon Mobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. <<Harz auf aromatischer Vinyl-Basis> >

[0127] An "aromatic vinyl-based resin" refers to a resin that incorporates an aromatic vinyl compound, such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, and the like, as a monomer component with the highest concentration, and may be one obtained by hydrogenation or modification thereof. A homopolymer of α-methylstyrene or styrene, or a copolymer of α-methylstyrene and styrene, is preferred as the aromatic vinyl-based resin, and a copolymer of α-methylstyrene and styrene is further preferred because it is economical, easy to process, and has excellent heat generation properties. Examples of aromatic vinyl-based resins that can be used include those commercially available from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. <<Harz auf Cumaron-Basis> >

[0128] A "coumaron-based resin" refers to a resin that includes coumaron as a monomer component and may be one obtained by hydrogenating or modifying it. Examples of preferred coumaron-based resins include a coumaron resin that is a polymer containing only coumaron as a monomer component, a coumaron-indene resin that is a copolymer containing coumaron and indene as monomer components, a coumaron-indene-styrene resin that is a copolymer containing coumaron, indene, and styrene as monomer components, and the like. Examples of suitable coumaron-based resins include those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. <<Harz auf Inden-Basis> >

[0129] An "indene-based resin" refers to a resin that includes indene as a monomer component and can be one obtained by hydrogenating or modifying it. Examples of indene-based resins include a coumaron-indene resin, which is a copolymer containing coumaron and indene as monomer components; a coumaron-indene-styrene resin, which is a copolymer containing coumaron, indene, and styrene as monomer components; and similar resins. Examples of indene-based resins that can be used include those commercially available from Rutgers Chemicals, Nitto Chemical Co., Ltd., Mitsui Chemicals, Inc., etc. <<Harz auf Terpen-Basis> >

[0130] A "terpene-based resin" refers to a resin that incorporates a terpene compound, such as α-pinene, β-pinene, limonene, dipentene, and the like, as a monomer component, and may be one obtained by hydrogenation or modification thereof. Preferred examples of terpene-based resins include a polyterpene resin, which is a polymer comprising only one or more of the terpene compounds as monomer components; an aromatically modified terpene resin, which is a copolymer comprising the terpene compound and an aromatic compound as monomer components; a terpenophenolic resin, which is a copolymer comprising the terpene compound and a phenolic compound as monomer components; and the like. Examples of aromatic compounds used as monomer components for aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, divinyltoluene, and the like.Examples of phenolic compounds used as monomer components for terpene phenolic resin include phenol, bisphenol A, cresol, xylenol, and the like. Terpene-based resins that can be used include those commercially available from companies such as Yasuhara Chemical Co., Ltd., Arakawa Chemical Industries, Ltd., and Nippon Terpene Chemicals, Inc. <<Harz auf Kolophonium-Basis> >

[0131] A "rosin-based resin" refers to a resin containing a rosin acid compound, such as abietic acid, neoabietic acid, palustric acid, isopimaric acid, and the like, and may be one obtained by hydrogenation or modification thereof. Examples of rosin-based resins include, for instance, natural resin rosin and rosin-modified resins obtained by modifying natural resin rosin through hydrogenation, disproportionation, dimerization, esterification, etc., but are not particularly limited. Examples of rosin-based resins include those commercially available from Harima Chemicals Group, Inc., Arakawa Chemical Industries, Ltd., IREC Co., Ltd., etc. <<Harz auf Phenol-Basis> >

[0132] A "phenol-based resin" refers to a resin that incorporates a phenolic compound, such as phenol, cresol, and the like, as a monomer component, and may be one obtained by hydrogenation or modification thereof. Examples of phenol-based resins include, but are not limited to, phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, oil-modified phenol-formaldehyde resins, terpene phenol resins, and the like. Examples of phenol-based resins include those commercially available from Sumitomo Bakelite Co., Ltd., DIC Corporation, ASAHI YUKIZAI CORPORATION, etc.

[0133] From the perspective of adhesion performance, the softening point of the resin component is preferably 60 °C or higher, more preferably 70 °C or higher, and even more preferably 80 °C or higher. Furthermore, from the perspective of processability and improved dispersibility of a rubber component with a filler, it is preferably 150 °C or lower, more preferably 140 °C or lower, and even more preferably 130 °C or lower. The softening point of the resin component is also measured using the measurement method described above.

[0134] The resin component content, when combined, is preferably 5 parts by mass or more per 100 parts by mass of the rubber component, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 18 parts by mass or more. Furthermore, from the perspective of suppressing heat generation, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. (Liquid rubber)

[0135] A liquid rubber is not particularly restricted as long as it is a polymer in a liquid state at 25 °C. Examples 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, and the like. The liquid rubber can be used alone, or two or more can be used in combination.

[0136] The liquid rubber content, when combined, is preferably 1 part or more per 100 parts by mass of the rubber component, more preferably 3 parts or more, and even more preferably 5 parts or more. Furthermore, the liquid rubber content is preferably 50 parts or less by mass, more preferably 40 parts or less, and even more preferably 20 parts or less. (Ester-based plasticizer)

[0137] Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), bis(2-ethylhexyl) azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), and the like. Ester-based plasticizers can be used alone, or two or more can be used in combination. (Vulcanized rubber particle)

[0138] A vulcanized rubber particle is a particle made from vulcanized rubber, and in particular, rubber powder and the like, as specified in JIS K 6316:2017, may be used. From an environmental and cost perspective, recycled rubber powder produced from a powdered end-of-life tire or the like is preferred. The vulcanized rubber particle may be used alone, or two or more may be used in combination.

[0139] The vulcanized rubber particle is not particularly restricted and can be an unmodified vulcanized rubber particle or a modified vulcanized rubber particle.

[0140] Commercially available vulcanized rubber products include, for example, products from Lehigh Technologies, Muraoka Rubber Reclaiming Co., Ltd., etc. (Wax)

[0141] The type of wax is not particularly restricted, and any wax commonly used in the tire industry may be suitable. Examples include mineral-based waxes, plant-derived waxes, and the like. Mineral-based waxes refer to waxes derived from mineral resources such as oil, natural gas, and the like. Plant-derived waxes refer to waxes derived from natural resources such as plants, and the like. Mineral-based waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, and the like. Examples of mineral-based waxes include paraffin wax, microcrystalline wax, specially selected waxes thereof, and the like. Paraffin wax is preferred.Furthermore, according to the present embodiment, the wax should not contain stearic acid. For example, waxes commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt BV, etc., can be used. One wax can be used alone, or two or more can be used in combination.

[0142] The wax content, when combined, based on 100 parts by mass of the rubber component, is preferably more than 0.5 parts by mass, more preferably more than 1.0 parts by mass, and even more preferably more than 1.5 parts by mass, from the perspective of improving the weather resistance of the rubber. Furthermore, from the perspective of preventing the whitening of a tire due to blooming, it is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass.

[0143] Examples of an antioxidant include, but are not limited to, a naphthylamine-based antioxidant such as phenyl-α-naphthylamine and the like; a diphenylamine-based antioxidant such as an octylated diphenylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine and the like; p-phenylenediamine-based antioxidants, such as 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 (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD), and the like; a quinoline-based antioxidant, such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline and the like;A monophenol-based antioxidant, such as 2,6-di-t-butyl-4-methylphenol, a styrenized phenol, and the like; bis-, tris-, and polyphenol-based antioxidants, such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane and the like. Among these, p-phenylenediamine-based 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 further preferred. Commercially available products may include, for example, those manufactured by Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexsys, etc. The antioxidant can be used alone, or two or more of them can be used in combination.

[0144] The antioxidant content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, with regard to the ozone crack resistance of a rubber. Furthermore, with regard to abrasion resistance and wet adhesion performance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0145] The stearic acid content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of processability. Furthermore, from the point of view of vulcanization rate, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0146] The zinc oxide content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of processability. Furthermore, from the point of view of abrasion resistance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0147] Sulfur is suitable for use as a vulcanizing agent. Suitable forms of sulfur include powdered sulfur, oil-processing sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and the like.

[0148] When combined as a vulcanizing agent, the sulfur content, based on 100 parts by mass of the rubber component, is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, to ensure a sufficient vulcanization reaction. Furthermore, to prevent deterioration, it is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.5 parts by mass or less. Additionally, when an oil-based sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is said to be the total content of pure sulfur contained in the oil-based sulfur.

[0149] Examples of vulcanizing agents other than sulfur include, for example, an alkylphenol-sulfur chloride condensate, sodium hexamethylene 1,6-bisthiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and the like. These alternative vulcanizing agents include those commercially available from Taoka Chemical Co., Ltd., LANXESS, Flexsys, etc.

[0150] Examples of vulcanization accelerators include, for instance, sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based, aldehyde-ammonia-based, imidazoline-based, and xantah-based accelerators, and the like. These vulcanization accelerators can be used individually, or two or more can be used in combination. Among these, one or more vulcanization accelerators selected from the group consisting of sulfenamide-based, guanidine-based, and thiazole-based accelerators are preferred, and sulfenamide-based vulcanization accelerators are further preferred for the sake of better preserving desired effects.

[0151] Examples of sulfenamide-based vulcanization accelerators include, for example, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like. Among these, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS) and N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) are preferred.

[0152] Examples of guanidine-based vulcanization accelerators include, for example, 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, 1,3-di-o-cumenyl-2-propionylguanidine, and the like. Among these, 1,3-diphenylguanidine (DPG) is preferred.

[0153] Examples of thiazole-based vulcanization accelerators include, for example, 2-mercaptobenzothiazole, a cyclohexylamine salt of 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and the like. Among these, 2-mercaptobenzothiazole is preferred.

[0154] The vulcanization accelerator content, when combined, based on 100 parts by mass of the rubber component, is preferably 1.0 parts by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2.0 parts by mass or more. Furthermore, the vulcanization accelerator content, based on 100 parts by mass of the rubber component, is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, even more preferably 6.0 parts by mass or less, and particularly preferably 5.0 parts by mass or less. When the vulcanization accelerator content is within the ranges described above, fracture toughness and elongation tend to be ensured.

[0155] In the present description, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining compounds of the various materials from carbon dioxide, carbon dioxide can be converted directly, or methane, obtained through a methanation step to synthesize methane from carbon dioxide, can be converted. [Production]

[0156] The rubber composition can be produced by a known process. For example, it can be produced by kneading each of the components described above using a rubber kneading device, such as an open roller, a closed-type kneader (Bunbury mixer, kneader, etc.), and the like.

[0157] The kneading step includes, for example, a basic kneading step of kneading compound and additives other than vulcanizing agents and vulcanization accelerators, and a final kneading step (F-kneading) of adding vulcanizing agents and vulcanization accelerators to the kneaded product obtained by the basic kneading step and kneading it. Furthermore, the basic kneading step can, if desired, be subdivided into several steps. In the case where the basic kneading step is subdivided, the process can be (1) a process of kneading some compound and additives into a masterbatch in advance and then adding the remaining compound and additives to the obtained masterbatch and kneading it, (2) a process of kneading all compound and additives at once in the basic kneading step and then rolling the kneaded product once or several times, or the like.In the above-described process (1), the number of masterbatches is not limited and can be two or more. Furthermore, if the number of masterbatches is two or more, all binders and additives used in the basic kneading step can be assigned to any one of the masterbatches.

[0158] A kneading condition is not particularly restricted. Examples of kneading include, for instance, a process of kneading at a discharge temperature of 150 to 170 °C for 3 to 10 minutes for the initial kneading step, and a process of kneading at 70 to 110 °C for 1 to 5 minutes for the final kneading step. A vulcanization condition is not particularly restricted. Examples of vulcanization include, for instance, a process of vulcanizing at 150 to 200 °C for 10 to 30 minutes.

[0159] The tire, comprising a tread section made of the rubber compound, can be produced using a standard procedure. Specifically, the tire can be produced by extruding an unvulcanized rubber compound—prepared by combining each of the rubber components described above as needed for a given component—into a tread section mold. This unvulcanized tread section is then assembled with other tire elements on a tire forming machine and molded using a standard unvulcanized tire forming process. Finally, the resulting unvulcanized tire is heated and pressurized in a vulcanizing machine. No specific vulcanization conditions are required.Examples of vulcanization include, for example, a process of vulcanizing at 150 to 200 °C for 10 to 30 minutes. [Applications]

[0160] In this description, the tire can be used for any application, whether pneumatic or deflated, and can be described 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. Preferably, it is a passenger car tire. Furthermore, a passenger car tire is defined as a tire mounted on a four-wheeled vehicle and refers to one with a maximum load capacity of less than 1400 kg. Additionally, in this description, the tire can be described as an all-season tire, a summer tire, or a winter tire, such as a studless tire, etc. EXAMPLES

[0161] Examples that are considered preferred for implementation (examples) are shown below, but the scope of protection of the present invention is not limited to examples.

[0162] Results are shown in Table 2, calculated on the basis of the evaluation procedures described below, considering a pneumatic tire comprising a tread section produced using a rubber composition obtained by modifying compounds according to Table 1 using various chemicals shown below. NR: TSR20 SBR: SLR6430, manufactured by The Dow Chemical Company (S-SBR, styrene content: 40 wt%, vinyl content: 20 mol%, Tg: -36 °C, comprising 37.5 wt parts of expanded oil content based on 100 wt parts of rubber component) BR: UBEPOL BR (registered trademark) 150B, manufactured by Ube Industries, Ltd. (cis content: 97 mol%) Soot: Show Black N134, manufactured by Cabot Japan KK (N2SA: 148 m 2 / g, average primary particle size: 18 nm) Silicon dioxide 1: Ultrasil (registered trademark) VN3, manufactured by Evonik Industries AG (N2SA: 175 m 2 / g, average primary particle size: 18 nm) Silicon dioxide 2: Ultrasil (registered trademark) 9100GR, manufactured by Evonik Industries AG (N2SA: 230 m 2 / g, average primary particle size: 15 nm) Coupling agent: Si266, manufactured by Evonik Industries AG (Bis(3-triethoxysilylpropyl)disulfide) Oil: Diana Process NH-70S, manufactured by Idemitsu Kosan Co., Ltd. (aromatic-based process oil) Resin component: SYLVATRAXX 4401, manufactured by Kraton Corporation (α-methylstyrene resin, Mw: 700, softening point: 85 °C) Zinc oxide: Zinc oxide No. 1, manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Stearic acid “CAMELLIA”, manufactured by NOF CORPORATION Wax: OZOACE 0355, manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: Nocrac 6C, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine) Antioxidant 2: Nocrac RD, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (Poly(2, 2, 4-Trimethyl-1,2-dihydroquinoline)) Sulfur: Seimi OT, manufactured by Nippon Kanryu Industry Co., Ltd. (10% oil-containing insoluble sulfur) Vulcanization accelerator 1: Nocceler CZ, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-Cyclohexyl-2-benzothiazolylsulfenamide (CBS)) Vulcanization accelerator 2: Nocceler D, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (1,3-Diphenylguanidine (DPG)) (Examples and comparisons)

[0163] According to the compound formulations shown in Table 1, using a closed 1.7-liter Banbury mixer, all chemicals other than sulfur and vulcanization accelerator are kneaded for 5 minutes until a discharge temperature of 170 °C is reached to obtain a kneaded product. Next, using an open twin-screw mixer, sulfur and vulcanization accelerator are added to the resulting kneaded product, and the mixture is kneaded for 4 minutes until the temperature reaches 105 °C to obtain an unvulcanized rubber composition.The resulting unvulcanized rubber composition is extruded into first and second layer tread sections using an extruder equipped with a pre-shaped die and joined with other tire elements to form an unvulcanized tire. The unvulcanized tire is then press-vulcanized at 170°C for 12 minutes to produce each test tire. <Messung von 30 °C-E*>

[0164] A rubber test piece measuring 20 mm in length × 4 mm in width × 1 mm in thickness is cut from the first layer of a tread section of each test tire, such that one side of the tire's circumference becomes the long side and one side of the tire's width becomes the thickness side. For each rubber test piece, a complex modulus of elasticity (30°CE*) is measured using EPLEXOR series materials manufactured by gabo Systemtechnik GmbH. This modulus is then measured at ±0.25% dynamic strain and 1.0% dynamic strain under conditions of 30°C, 10 Hz frequency, 5% initial strain, and a specific strain mode. The 30°C-ΔE* (0.25% - 1.0%) is calculated from the difference between the 30°CE* with ±0.25% dynamic strain and the 30°CE* with 1.0% dynamic strain. <Messung von Kautschukhärte>

[0165] Rubber hardness is measured by cutting out a tread section from a first layer of a tread section such that a tire radial direction becomes a thickness direction to produce a sample for measuring hardness, and by pressing a Type A hardness tester against the sample from the ground contact side at 23 °C according to JIS K 6253. <Lenkstabilität während Hochgeschwindigkeitslauf>

[0166] Each test tire is mounted on all wheels of a vehicle (domestic FF, 2000 cc), and actual driving consisting of 10 laps is conducted on a test track with a dry asphalt surface at approximately 120 km / h. Twenty test drivers perform a sensory evaluation of vehicle body roll during cornering, turning, and exiting. The evaluation is performed by all 20 test drivers using an integer value from 1 to 5 points (the smaller the roll, the higher the point) to calculate a total score. This total score from the reference comparison example (Comparison Example 4) is then converted into a reference value (100), and a rating for each test tire is given as an index proportional to the total score. The results show that the higher the numerical value, the better the steering stability during high-speed driving. Table 1 Connection of tread section C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 B Combined quantity NR 50 50 50 50 50 50 45 45 - 50 - - 30 70 SBR 55 55 55 55 55 55 61, 9 61,9 110 55 110 110 82,5 - (Rubber solids content) (40) (40) (40) (40) (40) (40) (45) (45) (80) (40) (80) (80) (60) - BR 10 10 10 10 10 10 10 10 20 10 20 20 10 30 soot 70 45 20 20 20 20 20 70 100 100 70 100 100 40 Silicon dioxide 1 40 70 100 - 100 - - 40 - - 40 - - - Silicon dioxide 2 - - - 100 - 100 100 - - - - - 25 - Clutching device 3,2 5, 6 8, 0 10, 0 8, 0 10, 0 10, 0 3,2 - - 3,2 - 2,5 - Öl 20 25 30 35 30 35 35 20 5 20 5 5 25 8 Resin component 20 20 20 20 20 20 20 20 20 20 20 20 20 - zinc oxide 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 2, 0 Stearic acid 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 3, 0 2, 0 wax 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 2,0 Antioxidant 1 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 Antioxidants 2 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 sulfur 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Vulcanization accelerator 1 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2, 0 2,0 2,0 2,0 2,0 2,0 2,0 1,5 Vulcanization accelerator 2 0, 8 1,2 1, 6 1, 8 1, 6 1, 8 1, 8 0, 8 - - 0, 8 - 0,3 - Physical property 30 °CE* (0.25 %) (MPa) 22,7 22,3 22, 0 24,8 22, 0 24,8 23,4 22,2 22,2 20,5 21, 6 22,2 25, 1 - 30 °CE* (1.0 %) (MPa) 16, 6 15, 8 15,0 16,7 15,0 16,7 16, 0 16,3 17,4 16,5 17,3 17,4 19, 1 - 30 °C-ΔE* (0.25% - 1.0%) (MPa) 6, 1 6,5 7, 0 8, 1 7, 0 8, 1 7,4 5, 9 4, 8 4,0 4,3 4, 8 6,0 - Rubber hardness 65 65 65 65 65 65 65 65 65 65 65 65 65 - Table 2 Example Comparative example 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 Connection of first layer C1 C2 C3 C4 C5 C6 C7 C8 C6 C6 C9 C10 C11 C12 e13 Connection of second layer B B B B B B B B B B B B B B B 30 °C-AE* (0.25 % - 1.0 %) 6, 1 6,5 7, 0 8, 1 7, 0 8, 1 7,4 5, 9 8, 1 8, 1 4, 8 4,0 4,3 4, 8 6, 0 T (mm) 13, 0 13, 0 13, 0 13, 0 10, 0 10, 0 10, 0 13, 0 10, 0 10, 0 13, 0 13, 0 13, 0 10, 0 15, 0 30 °C-ΔE* (0.25% - 1.0%) / d 0,47 0,50 0,54 0,62 0,70 0,81 0,74 0,45 0, 81 0, 81 0,37 0,31 0,33 0,48 0,40 Total volume of side groove / volume of tread section × 100 (%) 3,5 3,5 3,5 3,5 3,5 3,5 3,5 3,5 3,5 1, 0 3,5 3,5 3,5 3,5 3,5 Maximum width of inclined groove (mm) 12, 0 12, 0 12, 0 12, 0 12, 0 12, 0 12, 0 12,0 10, 0 10, 0 12,0 12,0 12,0 12,0 12,0 L 80 / L0 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 1, 0 1, 0 0,5 0,5 0,5 0,5 0,5 Steering stability index during high-speed running 106 108 112 116 114 118 116 105 115 111 96 90 94 100 98 <Ausführungsformen>

[0167] Examples of embodiments of the present invention are shown below. [1] A pneumatic tire comprising a tread section, wherein the tread section is made up of a rubber composition comprising a rubber component and silicon dioxide, where the content of an isoprene-based rubber in the rubber component is greater than 40% by mass, where the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, and where 30 °C-ΔE* (0.25 % - 1.0 %) represents a difference between a complex modulus of elasticity at a dynamic strain of 0.25 % and a complex modulus of elasticity at a dynamic strain of 1.0 %, measured under a condition of a temperature of 30 °C, a frequency of 10 Hz and an initial strain of 5 %, of the rubber composition, and T in mm represents a thickness of the tread section, 30 °C-ΔE* (0.25 % - 1.0 %) is 6.0 MPa or more, and 30 °C-ΔE* (0.25 % - 1.0 %) / T 0.45 or more. [2] The pneumatic tire of [1] above, wherein the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 60 parts by mass. [3] The pneumatic tire of [1] or [2] above, wherein the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 90 parts by mass. [4] The pneumatic tire from one of [1] to [3] above, where 30 °C-ΔE * (0.25 % - 1.0 %) is 7.0 MPa or more. [5] The pneumatic tire of one of [1] to [4] above, where 30 °C-ΔE* (0.25 % - 1.0 %) is 8.0 MPa or more. [6] The pneumatic tire from one of [1] to [5] above, where 30 °C-ΔE* (0.25 % - 1.0 %) / T is 0.60 or more. [7] The pneumatic tire of one of [1] to [6] above, where 30 °C-ΔE* (0.25 % - 1.0 %) / T is 0.75 or more. [8] The pneumatic tire of one of [1] to [7], wherein the rubber composition comprises carbon black and wherein the carbon black content, based on 100 parts by mass of the rubber component in the rubber composition, is greater than 1 part by mass and less than 25 parts by mass, preferably greater than 3 parts by mass and 20 parts by mass or less, and further preferably greater than 5 parts by mass and 20 parts by mass or less. [9] The pneumatic tire of one of [1] to [8] above, wherein a rubber hardness of the rubber composition is greater than 50 and less than 80, preferably greater than 55 and less than 75 and further preferably greater than 60 and less than 70.

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

[11] The pneumatic tire from [1] to

[10] above, wherein the tread section has one or more circumferential grooves extending in a tire circumferential direction and wherein one of the circumferential grooves has a ratio (L 80 / L0) of a groove width L 80 at an 80% position of a groove depth of the deepest section of the circumferential groove to a groove width L0 at a ground contact area of ​​the tread section 0.3 or more and 0.7 or less.

[12] The pneumatic tire from [1] to

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

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

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

[14] The pneumatic tire from [1] to

[13] above, where the pneumatic tire is a tire for a passenger car. REFERENCE MARK LIST 1 circumferential groove 2 Bridge section 3 First shift 4 Second shift 5 inclined side grooves 6 Running surface-ground contact area 10 tread section 11 Shoulder strap section 12 middle bridge section 21 side groove 22 Shoulder lamella 23 Middle lamella C tire equator W Tire width direction End of tread surface Total thickness of tread section N Normal to tread-ground contact area on tire equator H Groove depth of deepest section of circumferential groove L0 groove width at ground contact surface L 80 Groove width at 80% position of groove depth at deepest section< / weichmittel> < / silankupplungsmittel> < / kautschukkomponente> < / reifen> < / messverfahren> < / definitionen>

Claims

[1] Pneumatic tire, which includes a tread section, wherein the tread section is made up of a rubber composition comprising a rubber component and silicon dioxide, where the content of an isoprene-based rubber in the rubber component is greater than 40% by mass, where the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 30 parts by mass, and where 30 °C-ΔE* (0.25 % - 1.0 %) represents a difference between a complex modulus of elasticity at a dynamic strain of 0.25 % and a complex modulus of elasticity at a dynamic strain of 1.0 %, measured under a condition of a temperature of 30 °C, a frequency of 10 Hz and an initial strain of 5 %, of the rubber composition, and T in mm represents a thickness of the tread section, 30 °C−ΔE*(0.25%−1.0%)6.0 MPa or more, and 30 °C−ΔE*(0.25%−1.0%) / T 0.45 or more. [2] Pneumatic tire according to claim 1, wherein the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 60 parts by mass. [3] Pneumatic tire according to claim 1 or 2, wherein the silicon dioxide content based on 100 parts by mass of the rubber component in the rubber composition is greater than 90 parts by mass. [4] Pneumatic tire according to any one of claims 1 to 3, wherein 30 °C-ΔE* (0.25 % - 1.0 %) is 7.0 MPa or more. [5] Pneumatic tire according to any one of claims 1 to 4, wherein 30 °C-ΔE* (0.25 % - 1.0 %) is 8.0 MPa or more. [6] Pneumatic tire according to any one of claims 1 to 5, wherein 30 °C-ΔE* (0.25 % - 1.0 %) / T is 0.60 or more. [7] Pneumatic tire according to any one of claims 1 to 6, wherein 30 °C-ΔE* (0.25 % - 1.0 %) / T is 0.75 or more. [8] Pneumatic tire according to any one of claims 1 to 7, wherein the rubber composition comprises carbon black and wherein the carbon black content based on 100 parts by mass of the rubber component in the rubber composition is greater than 1 part by mass and less than 25 parts by mass. [9] Pneumatic tire according to any one of claims 1 to 8, wherein the rubber hardness of the rubber composition is greater than 50 and less than 80. [10] Pneumatic tire according to any one of claims 1 to 9, wherein the tread section has one or more lateral grooves extending in a tire width direction and wherein a total volume of the one or more lateral grooves is 2.0% or more and 5.0% or less of a volume of the tread section. [11] Pneumatic tire according to any one of claims 1 to 10, wherein the tread section has one or more circumferential grooves extending in a tire circumferential direction and wherein one of the one or more circumferential grooves has a ratio (L 80 / L0) of a groove width L 80 at an 80% position of a groove depth of the deepest section of the circumferential groove to a groove width L0 at a ground contact area of ​​the tread section 0.3 or more and 0.7 or less. [12] Pneumatic tire according to any one of claims 1 to 11, wherein the tread section has a groove inclined in a circumferential direction or a width direction and wherein a maximum width L of the groove inclined in the circumferential direction or the width direction is greater than 7.0 mm and less than 20.0 mm. [13] Pneumatic tire according to any one of claims 1 to 12, wherein T is greater than 6.0 mm and less than 12.0 mm. [14] Pneumatic tire according to any one of claims 1 to 13, wherein the pneumatic tire is a tire for a passenger car.

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