TIRES

Abstract

Tires, comprehensive: a tread section that has at least one layer of rubber, wherein a first layer, which forms a tread surface, is formed from a rubber composition containing a rubber component and a filler, the rubber composition contains 45 parts by mass of the filler in relation to 100 parts by mass of the rubber component, and if the maximum load capacity of the tire W L (kg) is a weight of the tire G (kg) is a height ratio at a ground contact area of ​​the tread section R is a complex modulus of elasticity at 30 °C of the rubber composition when dry, 30 °CE* D (MPa) is a complex modulus of elasticity at 30 °C of the rubber composition when wet, 30 °CE* W (MPa) is the tanδ at 30 °C of the rubber composition when dry, 30 °C-tanδ Dis and tanδ at 30 °C of the rubber composition, when water-wet, 30 °C-tanδ W is, W L , G, R, 30 °CE* D , 30 °CE* W , 30 °C-tanδ D and 30 °C tanδ W satisfy the following expressions (1) to (6): R ≥ 0.50 G / WL ≤ 0.025 | 30 °C − E * D − 30 °C − E * W | ≥ 1.3 | 30 °C − tan δ D − 30 °C − tan δ W | ≥ 0.03 | 30 °C − E * D − 30 °C − E * W | × R ≥ 0.70 | 30 °C − tan δ D − 30 °C − tan δ W | / (G / WL) ≥ 1.3

Description

Technical field

[0001] The present invention relates to a tire. State of the art

[0002] One technical improvement for a tread rubber composition is a technique of bonding silicon dioxide. List of citations from patent literature

[0003] [PTL 1] Japanese unexamined patent publication JP 2008 - 285 524 A Summary of the invention: Technical problem

[0004] As shown in PTL 1, the wet grip performance of a tire is improved by bonding silicon dioxide. On the other hand, changes in grip performance when a road surface changes from dry to wet, or vice versa, remain a significant engineering challenge, and there is room for improvement.

[0005] Another method for improving wet grip performance involves incorporating a plasticizer into a tread rubber compound to soften the rubber. However, softening the tread rubber can negatively impact fuel efficiency on dry road surfaces.

[0006] One object of the present invention is to provide a tire that is able to improve overall performance in terms of wet grip, dry grip and fuel efficiency. Solution to the problem

[0007] The present invention relates to a tire comprising a tread section having at least one rubber layer, wherein a first layer forming a tread surface is formed from a rubber composition containing a rubber component and a filler, the rubber composition containing 45 parts by mass of the filler in relation to 100 parts by mass of the rubber component, and, if a maximum load capacity of the tire W L (kg) is a weight of the tire G (kg) is a height ratio at a ground contact area of ​​the tread section R is a complex modulus of elasticity at 30 °C of the rubber composition when dry, 30 °CE* D (MPa) is a complex modulus of elasticity at 30 °C of the rubber composition when wet, 30 °CE* W (MPa) is the tanδ at 30 °C of the rubber composition when dry, 30 °C-tanδ Dis and tanδ at 30 °C of the rubber composition, when water-wet, 30 °C-tanδ W is, W L , G, R, 30 °CE* D , 30 °CE* W , 30 °C-tanδ D and 30 °C tanδ W satisfy the following expressions (1) to (6): R≥0.50 G / WL≤0.025 |30 °C−E*D−30 °C−E*W|≥1.3 |30 °C−tanδD−30 °C−tanδW|≥0.03 |30 °C−E*D−30 °C−E*W|×R≥0.70 |30 °C−tanδD−30 °C−tanδW| / (G / WL)≥1.3 Advantageous effects of the invention

[0008] According to the present invention, a tire can be provided which is able to improve overall performance in terms of wet grip, dry grip and fuel efficiency.

[0009] In the tire according to the present invention, the reason why the overall performance of wet grip, dry grip and fuel efficiency is improved is not intended to be limited by theory, but is assumed to be as follows. (1) The tire according to the present invention ensures drainage performance and contributes to improved traction by adjusting the lift ratio R to be 0.50 or greater. Furthermore, (2) the G / W L set to 0.025 or less to achieve weight reduction of the tire, thereby contributing to improved fuel efficiency performance.

[0010] Furthermore, the rubber composition formed from the first layer that constitutes the tread surface is a rubber composition in which the complex modulus of elasticity and tanδ are reversibly modified by water, so that the wet and dry adhesion performance can be synergistically improved. In particular, (3) is assumed that by creating a difference between 30 °CE* D and 30 °CE* W When set to a constant value or higher, the tire becomes soft in a wet environment while maintaining dry grip and steering stability, thus improving the contact patch when wet. Furthermore (4) it is assumed that by setting a difference between 30 °C-tanδ D and 30 °C tanδ W It can be improved to a constant value or more adhesion while maintaining the usual fuel efficiency performance.

[0011] Furthermore (5) it is assumed that in a case where a product of |30 °CE* D -30 °CE* W | and R is equal to or greater than a certain value and a difference between 30 °CE* D and 30 °CE* W Since the contact area with the road surface is small, the ground contact area with the road surface can be increased by increasing R, and the effect of the change in the rubber can be enhanced. Furthermore (6) it is assumed that in a case where a ratio of |30 °C-tanδ D -30 °C tanδ W | to G / W L is set to a specific value or more, and there is a difference between 30 °C-tanδ D and 30 °C tanδ W small, while maintaining fuel efficiency performance, adhesion can be improved by G / W L is reduced.

[0012] It is assumed that the interaction of the above (1) to (6) will produce a remarkable effect of improving the overall performance of wet adhesion performance, dry adhesion performance and fuel efficiency performance. Description of embodiments

[0013] A tire according to an embodiment of the present invention is a tire comprising a tread section having at least one rubber layer, wherein a first layer forming a tread surface is formed from a rubber composition containing a rubber component and a filler, the rubber composition containing 45 parts by mass of the filler in relation to 100 parts by mass of the rubber component, and, if a maximum load capacity of the tire W L(kg) is a weight of the tire G (kg) is a height ratio at a ground contact area of ​​the tread section R is a complex modulus of elasticity at 30 °C of the rubber composition when dry, 30 °CE* D (MPa) is a complex modulus of elasticity at 30 °C of the rubber composition when wet, 30 °CE* W (MPa) is the tanδ at 30 °C of the rubber composition when dry, 30 °C-tanδ D is and tanδ at 30 °C of the rubber composition, when water-wet, 30 °C-tanδ W is, W L , G, R, 30 °CE* D , 30 °CE* W , 30 °C-tanδ D and 30 °C tanδ W satisfy the following expressions (1) to (6): R≥0.50 G / WL≤0.025 |30 °C−E*D−30 °C−E*W|≥1.3 |30 °C−tanδD−30 °C−tanδW|≥0.03 |30 °C−E*D−30 °C−E*W|×R≥0.70 |30 °C−tanδD−30 °C−tanδW| / (G / WL)≥1.3

[0014] From the point of view of improving adhesion performance, the rubber composition preferably contains 40 parts by mass or more of silicon dioxide in relation to 100 parts by mass of the rubber component.

[0015] From the point of view of suppressing heat generation by increasing the specific surface area of ​​the silicon dioxide and increasing the interaction with the rubber component to suppress the movement of the molecular chain, the average primary particle diameter of the silicon dioxide is preferably 20 nm or less.

[0016] From the point of view of softening the rubber and improving its ability to follow the road surface, it is preferred that the rubber composition contains 5 parts by mass or more of a plasticizer in relation to 100 parts by mass of the rubber component.

[0017] From the point of view of improving adhesion performance, the plasticizer preferably contains at least one selected from the group consisting of a resin component and a liquid polymer.

[0018] From the point of view of improving abrasion resistance, the rubber component preferably contains 10 wt% or more of a butadiene rubber.

[0019] From the point of view of ensuring reinforcement, the amount of sulfur in the rubber composition is preferably 0.1 wt% or more.

[0020] A glass transition temperature of the rubber composition is preferably -10 °C or lower from the point of view of cold brittleness.

[0021] The 30 °CE* D The rubber composition is preferably 3.0 MPa or more from the point of view of ensuring steering stability performance.

[0022] The 30 °C tanδ DThe rubber composition, from the point of view of dry adhesion performance, is preferably 0.10 or more. <definitionen>

[0023] The "tread section" is a section that forms a ground contact area of ​​the tire, and in a tire radial direction cross-section, in a case where the tread section contains an element that forms a tire skeleton using a steel or textile material, such as a belt layer, a belt reinforcement layer, and a carcass layer, the tread section is an element that is located on the outside of these layers in the tire radial direction.

[0024] The "belt layer" is a layer provided on the outside of the carcass layer in the tire radial direction and corresponds to several working layers in which an internal reinforcing material is inclined at about 18° to 30° with respect to a tire circumferential direction and which overlap in an opposite direction, a circumferential belt layer in which the internal reinforcing material is oriented at an angle of ±10° with respect to the tire circumferential direction, and the like.

[0025] The "normal state" is a state in which the tire is mounted on a normal rim, inflated to a normal internal pressure, and no tire load is applied.

[0026] Unless otherwise noted, with respect to a “dimension of each section of the tire”, a dimension appearing on an outer surface of the tire is a value specified in a normal condition, and a dimension on an inner section of the tire or on a cut surface of the tire is a value specified, for example, when the tire is cut along a plane containing a tire axis of rotation and the cut piece of the tire is held to the rim width of the normal rim.

[0027] The "normal rim" is a rim that, for each tire, is defined by a standard that includes one on which the tire is based. For example, the normal rim refers to the standard rim of an applicable size described in the "JATMAYEAR BOOK" of the Japan Automobile Tire Association (JATMA), the "Measuring Rim" described in the "STANDARDS MANUAL" of The European Tyre and Rim Technical Organisation (ETRTO), and the "Design Rim" described in the "YEAR BOOK" of The Tire and Rim Association, Inc. (TRA). References are made to JATMA, ETRTO, and TRA in that order, and if an applicable size exists at the time of reference, the normal rim follows that standard.In the case of a tire not defined in the above standard, the normal rim refers to a rim with the smallest width among the rims with the minimum diameters on which the tire can be mounted and which can maintain the internal pressure (that is, a rim that does not cause air leakage between the rim and the tire).

[0028] The "normal inflation pressure" is an air pressure determined for each tire by a standard that encompasses the one on which the tire is based. For example, normal inflation pressure refers to the "maximum inflation pressure" for JATMA, "inflation pressure" for ETRTO, and the maximum value listed in the "Tire Load Limits at Various Cold Inflation Pressures" table for TRA. Reference is made to JATMA, ETRTO, and TRA in that order, and if an applicable size exists at the time of reference, the inflation pressure follows that standard.In the case of a tire not defined in the above standard, the normal rim refers to a normal internal pressure (but 250 kPa or more) of a different tire size described with the normal rim as a standard rim (but defined in the standard), and in the case where several normal pressures of 250 kPa or more are listed, reference is made to the minimum value among the pressure values.

[0029] The "normal load" is a load determined for each tire by a standard that encompasses the tire's design. For example, the normal load refers to the "maximum load capacity" in JATMA, the "LOAD CAPACITY" in ETRTO, and the maximum value described in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table in TRA. Reference is made to JATMA, ETRTO, and TRA in that order, as in the cases of normal rim and normal inflation pressure, and if an applicable size exists at the time of reference, the normal load follows the standard. Then, in the case of a tire not defined in the standard, the separately calculated maximum load capacity W is used. L used as the normal load.

[0030] The "maximum load capacity W" L The volume is calculated using the following formula. "V" is a virtual volume of the tire (mm³). 3 ), “Dt” is a tire outer diameter (mm) in normal conditions, “Ht” is a tire cross-sectional height (mm) in the tire radial direction on the plane containing the tire axis of rotation, and “Wt” is a tire cross-sectional width (mm) in normal conditions. If the tire rim diameter is R, Ht can be obtained by (Dt - R) / 2. If a pattern, mark, or the like is provided on a tire sidewall, Wt is a value obtained by subtracting the pattern, mark, or the like. The maximum load capacity is synonymous with the normal load. WL=0.000011×V+175 V={(Dt / 2)2−(Dt / 2−Ht)2}×π×Wt

[0031] The "ground contact area" is the area of ​​the tread obtained from a contour when the tire is pressed against the ground. It is obtained by mounting the tire on a standard rim, applying normal internal pressure, leaving the tire at 25°C for 24 hours, then applying ink to the tire tread surface, applying the normal load (maximum load capacity) to the tire, and pressing the tire perpendicular to a piece of thick paper (at a camber angle of 0°) to transfer the ink. The area of ​​the ground contact area is referred to as the "total ground contact area." The total ground contact area can be calculated by performing the transfer work described above for a total of five locations, rotating the tire 72° each time, and calculating an average of the five obtained areas.

[0032] The "effective contact patch" is the area of ​​the tread where the tire makes contact with the ground when pressed against it. It is obtained by mounting the tire on a standard rim, inflating it to normal pressure, leaving it at 25°C for 24 hours, then applying ink to the tread surface, applying a normal load (maximum load capacity) to the tire, and pressing the tire perpendicular to a piece of thick paper (at a camber angle of 0°) to transfer the ink. The area of ​​the effective contact patch is referred to as the "effective contact area." The effective contact area can be calculated by performing the transfer work described above at a total of five locations, rotating the tire 72° each time, and obtaining an average of the five measured areas.

[0033] The “elevation ratio R” is calculated from the total ground contact area for the ground contact area and the effective ground contact area for the effective ground contact area using the following expression. (Survey ratio) = (effective ground contact area / total ground contact area)

[0034] The expression "reversibly altered by water" means that the physical properties of a vulcanized rubber composition are reversibly changed by the presence of water. For example, in a case where the state changes from a dry state to a wet state and then back to a dry state, it is sufficient that the physical properties are reversibly changed, and it is possible that the physical properties in a first dry state and a second dry state are not necessarily the same.

[0035] The "plasticizer" is a material that imparts plasticity to the rubber component and is extracted from the rubber composition using acetone. The plasticizer comprises a plasticizer that is liquid at 25°C and a plasticizer that is solid at 25°C. However, it does not contain waxes or stearic acid, which are commonly used in the tire industry.

[0036] A "plasticizer content" comprises the amount of plasticizer contained in the rubber component pre-stretched by the plasticizer, such as an oil, resin component, or liquid rubber component. Furthermore, this also applies to an oil content, a resin component content, and a liquid rubber content; for example, in a case where the stretching component is oil, the stretching oil is included in the oil content. <messverfahren>

[0037] “30 °CE*” is a complex modulus of elasticity measured using a dynamic viscoelasticity measuring device (for example, the EPLEXOR series, manufactured by GABO) under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 1%, and a strain mode. A sample for measuring 30 °CE* is a vulcanized rubber compound with a length of 20 mm, a width of 4 mm, and a thickness of 1 mm. In a case where the sample is prepared by cutting it from a tire, the sample is cut from a tread section of the tire such that the tire's circumferential direction becomes a long side and the tire's radial direction becomes a thickness direction. A sample for measuring 30 °CE* W The measurement is obtained by immersing the vulcanized rubber test piece in water at 25 °C for 12 hours. Additionally, a sample is heated to 30 °C*. D -Measurement obtained by drying the vulcanized rubber composition after wetting with water under reduced pressure under conditions of 1 kPa or less at 80 °C until its weight becomes constant.

[0038] "30 °C-tanδ" is a loss tangent measured using a dynamic viscoelasticity measuring device (for example, EPLEXOR series, manufactured by GABO) under the conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 1%, and a strain mode. Samples for 30 °C-tanδ W and 30 °C tanδ D will be in the same way as in the case of 30 °CE* W and 30 °CE* D manufactured.

[0039] A "glass transition temperature (Tg) of the rubber composition" is a temperature (tanδ peak temperature) that corresponds to a maximum value in the range of -60 °C or higher and 40 °C or lower on a temperature distribution curve obtained by measuring the temperature distribution curve of tanδ using a dynamic viscosity measuring device (for example, EPLEXOR series, manufactured by GABO) under conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a temperature rise rate of 2 °C / min. If the tanδ value gradually and continuously decreases or increases with a temperature rise during measurement in the range of -60 °C to 40 °C, the glass transition temperature of the rubber composition is accordingly 40 °C or -60 °C.Furthermore, in a case where there are two or more points where tanδ has its maximum value in a range of -60 °C or higher and 40 °C or lower, the lowest temperature point of these temperature points is defined as the glass transition temperature.

[0040] The "amount of sulfur" is the amount of sulfur (mass %) measured by an oxygen combustion piston method in accordance with JIS K 6233 2016. A sample for measuring the amount of sulfur is a vulcanized rubber compound measuring 20 mm in length, 4 mm in width, and 1 mm in thickness. In a case where the sample is prepared by cutting from a tire, the sample is cut from a tread section of the tire such that the tire's circumferential direction becomes a long side and the tire's radial direction becomes a thickness direction.

[0041] The "styrene content" is a value determined by 1 H-NMR measurement is calculated and applied to a rubber component with a repeating unit derived from styrene, such as SBR.

[0042] A “vinyl content (1,2-bonded butadiene unit amount)” is a value calculated by infrared absorption spectrometry in accordance with JIS K 6239-2: 2017 and is applied to a rubber component with a repeating unit derived from butadiene, such as SBR and BR.

[0043] A “cis content (cis-1,4-polybutadiene unit amount)” is a value calculated by infrared absorption spectrometry in accordance with JIS K 6239-2: 2017 and is applied to a rubber component with a repeating unit derived from butadiene, such as BR.

[0044] A weight-mean molecular weight (Mw) can be obtained for a standard polystyrene based on measurements obtained by gel permeation chromatography (GPC) (e.g., GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). For example, Mw is applied to SBR, BR, a plasticizer, or the like.

[0045] A “specific nitrogen adsorption surface (N2SA) of soot” is measured in accordance with JIS K 6217-2: 2017.

[0046] A “specific nitrogen adsorption surface (N2SA) of silicon dioxide” is measured by a BET method in accordance with ASTM D3037-93.

[0047] The "average primary particle diameter" is obtained by photographing the particles with a transmission electron microscope or a scanning electron microscope and by taking the arithmetic mean of the particle diameters of 400 particles. In a case where the particle shape is substantially circular, the diameter of the circle is taken as the particle diameter, and in a case where the particle shape is needle-shaped or rod-shaped, the minor axis is taken as the particle diameter. In other cases, the circle-equivalent diameter is calculated from an electron microscope image and used as the particle diameter. The circle-equivalent diameter is obtained as a positive square root of [4 × (area of ​​the particle) / π]. The average primary particle diameter is applied to silicon dioxide, carbon black, or the like.

[0048] The “softening point of the resin component” is a softening point defined in accordance with JIS K 6220-1: 2015 7.7 and is the temperature at which a ball falls, as measured by a ring-and-ball softening point measuring device.

[0049] A process for producing a tire according to one embodiment of the present invention is described in detail below. However, the following description is merely an example to illustrate the present invention and is not intended to limit the technical scope of the present invention to the area described. [Tires]

[0050] In the tire according to the present embodiment, the ratio (G / W) is L ) of a tire weight G (kg) to a maximum load capacity W L (kg) from the point of view of the effects of the present invention, 0.025 or less, preferably 0.024 or less, more preferably 0.023 or less, even more preferably 0.022 or less, and particularly preferably 0.021 or less. On the other hand, the lower limit of the G / W is L From the perspective of the effects of the present invention, the tire weight G is not particularly limited and can be, for example, 0.012 or more, 0.013 or more, and 0.014 or more. The tire weight G can be varied by a conventional method; that is, the tire weight G can be increased by increasing the specific gravity of the tire or by increasing the thickness of each element of the tire, and can be decreased by the opposite.

[0051] The maximum load capacity W L (kg) is preferably 300 or more, more preferably 400 or more, even more preferably 450 or more, and particularly preferably 500 or more, from the perspective of further improving the effect of the present invention. Furthermore, the maximum load capacity W can L (kg) for example, from the perspective of further improving the effect of the present invention, 1,300 or less, 1,200 or less, 1,100 or less, 1,000 or less, 900 or less, 800 or less and 700 or less. The maximum load capacity W L The tire's resistance can be increased by increasing the virtual volume V of the space it occupies, and it can be decreased by doing the opposite.

[0052] The tire weight G is preferably 8.0 kg or more, more preferably 8.5 kg or more, even more preferably 9.0 kg or more, and particularly preferably 9.5 kg or more. However, an upper limit for the tire weight G is not particularly restricted; it is 100 kg or less and can be, for example, 80 kg or less, 60 kg or less, 40 kg, 20 kg, 15 kg or less, or the like.

[0053] The rake ratio R on the ground contact surface of the tread section is 0.50 or more to ensure drainage performance and improve grip, and is preferably 0.53 or more, further preferably 0.56 or more, and even more preferably 0.59 or more. Furthermore, to ensure drainage performance and suppress aquaplaning, the rake ratio R is preferably 0.85 or less, further preferably 0.80 or less, and even more preferably 0.75 or less. The rake ratio R can be modified by a conventional method; that is, the rake ratio R can be increased by reducing the groove area of ​​the tread surface, and the rake ratio R can be decreased by the opposite.

[0054] The running surface according to the present embodiment comprises at least one rubber layer. The running surface according to the present embodiment can be a running surface containing a single rubber layer, or it can be a running surface comprising a first layer with an outer surface forming the running surface, and one or more rubber layers (inner rubber layers) existing between the first layer and a belt layer.

[0055] The thickness of the first layer in relation to the thickness of the entire tread section may, for example, be 30% or more, 50% or more, 70% or more, or 90% or more, and the tread section may consist of only the first layer.

[0056] The 30 °CE* D From the perspective of its ability to follow the road surface, the resistance is preferably 50 MPa or less, more preferably 30 MPa or less, and even more preferably 15 MPa or less. On the other hand, the resistance is 30 °CE*. D From the perspective of ensuring steering stability performance, preferably 3.0 MPa or more, further preferably 4.0 MPa or more, even more preferably 5.0 MPa or more and particularly preferably 6.0 MPa or more.

[0057] The 30 °CE* W From the perspective of its ability to follow the road surface, the resistance is preferably 50 MPa or less, more preferably 30 MPa or less, and even more preferably 15 MPa or less. On the other hand, the resistance is 30 °CE*. W From the perspective of ensuring steering stability performance, preferably 2.0 MPa or more, further preferably 3.0 MPa or more, even more preferably 4.0 MPa or more and particularly preferably 5.0 MPa or more.

[0058] The 30 °C tanδ D From the perspective of dry adhesion performance, the value is preferably 0.10 or more, more preferably 0.15 or more, and even more preferably 0.18 or more. Furthermore, from the perspective of fuel efficiency performance, the 30 °C tanδ value is... D preferably 0.50 or less, further preferably 0.45 or less, even more preferably 0.40 or less and most preferably 0.35 or less.

[0059] Furthermore, 30 °C-tanδ W From the perspective of wet adhesion performance, preferably 0.10 or more, further preferably 0.15 or more, and even more preferably 0.18 or more. Furthermore, from the perspective of fuel efficiency performance, 30 °C tanδ is D preferably 0.50 or less, further preferably 0.45 or less, even more preferably 0.40 or less and most preferably 0.35 or less.

[0060] The 30 °CE* D , 30 °CE* W , 30 °C-tanδ D and 30 °C tanδ W can be appropriately adapted according to the type and quantity of the rubber component, resin component, oil or the like, as described below.

[0061] The amount of sulfur in the rubber composition forming the first layer is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, and even more preferably 0.5 wt% or more, to ensure reinforcement. On the other hand, the upper limit for the amount of sulfur in the rubber composition is not particularly restricted and is typically 2.5 wt% or less. Since the amount of sulfur is within the above range, a sufficient crosslinking point between the polymers is maintained, and thus polymer deformation is less likely. The amount of sulfur in the rubber composition can be suitably adjusted by the combination of sulfur and vulcanization accelerator, as described below.

[0062] The glass transition temperature (Tg) of the rubber composition forming the first layer is, from the perspective of the effect of the present invention, preferably -100 °C or higher, more preferably -80 °C or higher, even more preferably -60 °C or higher, and particularly preferably -50 °C or higher. Furthermore, from the perspective of ensuring cold brittleness, the glass transition temperature is preferably 0 °C or lower, more preferably -10 °C or lower, and even more preferably -15 °C or lower. The Tg of the rubber composition can be suitably adjusted depending on the type and quantity of the rubber component, the filler, and the plasticizer to be described later.

[0063] The rubber composition forming the first layer according to the present embodiment is characterized in that the rubber composition satisfies the following expressions (3) and (4): |30 °C−E*D−30 °C−E*W|≥1.3 |30 °C−tanδD−30 °C−tanδW|≥0.03

[0064] The value of |30 °CE* D -30 °CE* W | is preferably 1.4 or more and more preferably 1.5 or more. It is assumed that an increase in the ground contact area of ​​the tread section can be expected due to softening by water, by |30 °CE* D -30 °CE* W | is set within the above range. On the other hand, the upper limit is |30 °CE* D -30 °CE* W | not particularly restricted and is usually 10 or less, preferably 7.0 or less, more preferably 4.0 or less and still more preferably 2.0 or less.

[0065] |30 °C-tanδ D -30 °C tanδ W | is preferably 0.04 or more and further preferably 0.05 or more. It is assumed that the improvement in adhesion performance can be expected by |30 °C-tanδ D -30 °C tanδ W | is set within the above range. On the other hand, the upper limit of |30 °C-tanδ D -30 °C tanδ W | not particularly restricted and is usually 0.20 or less, preferably 0.15 or less and more preferably 0.10 or less.

[0066] The tire according to the present embodiment is characterized in that the tire fulfills the following expressions (5) and (6): |30 °C−E*D−30 °C−E*W|×R≥0.70 |30 °C−tanδD−30 °C−tanδW| / (G / WL)≥1.3

[0067] |30 °CE* D -30 °CE* W | × R is preferably 0.75 or more and more preferably 0.80 or more. It is assumed that the rubber properties can be modified and the optimal synergistic effect of the tire structure can be produced by |30 °CE* D -30 °CE* W | × R is set within the above range. On the other hand, the upper limit is |30 °CE* D -30 °CE* W | × R is not particularly restricted and is usually 1.50 or less, and preferably 1.30 or less.

[0068] |30 °C-tanδ D -30 °C tanδ W | / (G / W L ) is preferably 1.4 or more, more preferably 1.6 or more, still more preferably 1.8 or more, still more preferably 2.0 or more, and particularly preferably 2.1 or more. It is assumed that the adhesion performance and the fuel efficiency performance can be expected to be compatible with each other by |30 °C-tanδ D -30 °C tanδ W | / (G / W L ) is set within the above range. On the other hand, the upper limit of |30 °C-tanδ is D -30 °C tanδ W | / (G / W L ) not particularly restricted and is usually 5.0 or less, preferably 4.0 or less and more preferably 3.5 or less. [Rubber composition]

[0069] The tire according to the present embodiment can more effectively improve the overall performance of wet grip, dry grip, and fuel efficiency through the interaction of the tire and tread configurations described above and the above-described physical properties of the rubber compound forming the tread section. The rubber compound forming the first layer is described below.

[0070] In the present embodiment, it is advantageous to form part of the crosslinking created by the rubber composition via a bond formed through electrostatic interaction, such as ionic bonding or the like, in order to reversibly modify the complex elastic modulus and tanδ of the rubber composition with water. If the rubber composition contains a bond formed through electrostatic interaction, the bond can be reversibly broken when water is incorporated into the rubber composition. Therefore, the complex elastic modulus of the rubber composition can be reduced when wet, and tanδ is increased by improving hysteresis loss due to bond dissociation. Furthermore, since ionic bonding exhibits the highest bond strength among non-covalent bonds, the bond strength can be maintained when dry.To form the bond through electrostatic interaction in the rubber composition, a hydrophilic functional group (for example, a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon, and sulfur; preferably, a functional group containing at least one element selected from the group consisting of a carboxyl group, an amino group, and a hydroxyl group) can be modified in the rubber component, the resin component, the silicon dioxide, the silane coupling agent, or the like, as described below.

[0071] Among the bonds formed by electrostatic interaction, ionic bonding can be introduced into the crosslinking structure of the rubber composition. In this description, such a material is referred to as an "ionic material." Examples of ionic materials include ionically modified rubber, ionically modified silicon dioxide, ionically modified silane coupling agents, ionically modified plasticizers, and the like, which are modified to be capable of forming ionic bonds. Examples of ionically bonded plasticizers include ionically modified resins, ionically modified liquid polymers, and the like. Specific examples of ionic materials are described in each of the columns for rubber component, silicon dioxide, silane coupling agent, and plasticizer. [Rubber composition]

[0072] The rubber composition (hereinafter referred to as the rubber composition according to the present embodiment), which forms the tread section of the tire according to the present embodiment, contains a rubber component and a filler and can be produced using the raw materials described below. The rubber composition according to the present embodiment is described below. <kautschukkomponente>

[0073] A diene-based rubber is suitably used as the rubber component of the rubber composition according to the present embodiment. Examples of diene-based rubbers include isoprene-based rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like. The diene-based rubbers may be modified rubbers treated with a modifying group that can interact with a filler, such as carbon black or silicon dioxide, or they may be hydrogenated rubbers in which part of the unsaturated bond undergoes treatment involving the addition of hydrogen.Among the modified rubbers, a modified rubber into which a hydrophilic functional group has been introduced can be used as a suitable ionically modified rubber. A diene-based rubber can be a stretched rubber that has been pre-stretched by using the plasticizer described later. The diene-based rubber can be used alone, or two or more types of it can be used in combination.

[0074] The content of diene-based rubber in the rubber component is preferably 70 wt% or more, more preferably 80 wt% or more, even more preferably 90 wt% or more, and particularly preferably 95 wt% or more. Furthermore, the rubber component can consist solely of diene-based rubber.

[0075] The diene-based rubber component is at least one selected from the group consisting of isoprene-based rubber, styrene-butadiene rubber (SBR), and butadiene rubber (BR). The rubber component preferably contains SBR, more preferably SBR and an isoprene-based rubber and / or BR, more preferably an isoprene-based rubber, BR, and SBR, and can be a rubber component formed from an isoprene-based rubber, SBR, and BR. (Isoprene-based rubber)

[0076] Isoprene-based rubber is not particularly restricted, and examples include natural rubber (NR), isoprene rubber (IR), and modified natural rubber. Examples of NR include SIR20, RSS#3, TSR20, and the like. Examples of IR include IR2200. Examples of modified natural rubber include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, grafted natural rubber, and the like. These isoprene-based rubbers can be used alone, or two or more types can be used in combination.

[0077] From the perspective of the effect of the present invention, the content of isoprene-based rubber in the rubber component is preferably 50 wt% or less, more preferably 40 wt% or less, even more preferably 30 wt% or less, and particularly preferably 20 wt% or less. Furthermore, the lower limit of the content is not particularly restricted, and, for example, the lower limit may be 1 wt% or more, 3 wt% or more, 5 wt% or more, 7 wt% or more, or 10 wt% or more. (SBR)

[0078] The SBR is not particularly restricted, and examples include solution polymerization SBR (S-SBR), unmodified emulsion polymerization SBR (E-SBR), and modified SBRs (modified S-SBR or modified E-SBR). Examples of modified SBRs include SBRs in which one end and / or main chain is modified, modified SBRs coupled with tin, a silicon compound, or the like (a condensate, a branched structure, or the like), and the like. Among these, S-SBRs and modified SBRs are preferred. Furthermore, hydrogenated products of these SBRs (hydrogenated SBRs) and the like may also be used. These SBRs may be used individually, or two or more types of them may be used in combination.

[0079] Among the modified SBRs, an SBR that is modified at the end and / or the main chain with a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon and sulfur can be suitablely used as an ionically modified SBR. Examples of the functional group include an amino group (preferably an amino group in which one hydrogen atom of the amino group is substituted by an alkyl group with 1 to 6 carbon atoms), an amide group, a sillyl group, an alkoxysillyl group (preferably an alkoxysillyl group with 1 to 6 carbon atoms), an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group,An azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group (preferably an alkoxy group with 1 to 6 carbon atoms), a hydroxyl group, an oxy group, an epoxy group, and the like, and one or more functional groups selected from the group consisting of an amino group, a carbonyl group, and an alkoxysilyl group are preferred. The functional groups may include a substituent. Examples of substituents include an amino group, an amide group, an alkoxysilyl group, a carboxyl group, and a hydroxyl group. The modified SBR may be a hydrogenated SBR, an epoxy-modified SBR, a tin-modified SBR, or the like.

[0080] The SBR according to the present embodiment can be either a stretched or an undiluted SBR. In the case of using the stretched SBR, the amount of stretching of the SBR, that is, the content of a stretching plasticizer contained in the SBR, is preferably 10 to 50 parts by mass in relation to 100 parts by mass of the rubber solids content of the SBR.

[0081] The SBRs listed above can be used individually, or two or more types can be used in combination. Examples of SBRs that can be used include those commercially available from Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., ZS Elastomer Co., Ltd., and similar companies.

[0082] The styrene content of the SBR is preferably 40 wt% or less, more preferably 37 wt% or less, even more preferably 34 wt% or less, and particularly preferably 30 wt% or less. Furthermore, the styrene content of the SBR is preferably 5 wt% or more, more preferably 7 wt% or more, even more preferably 10 wt% or more, and particularly preferably 12 wt% or more. The styrene content of the SBR is measured by the measurement method described above.

[0083] The vinyl content of the SBR is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, to ensure reactivity with silicon dioxide and abrasion resistance. Furthermore, to improve elongation at break and abrasion resistance, the vinyl content of the SBR is preferably 65 mol% or less, and more preferably 60 mol% or less. In this description, the vinyl content of the SBR is measured using the method described above.

[0084] From the perspective of the effect of the present invention, the weight-average molecular weight (Mw) of the SBR is preferably 100,000 or more, more preferably 200,000 or more, and even more preferably 300,000 or more. Furthermore, from the perspective of crosslinking uniformity, the weight-average molecular weight is preferably 2,000,000 or less, more preferably 1,800,000 or less, and even more preferably 1,500,000 or less. The weight-average molecular weight of the SBR is measured by the measurement method described above.

[0085] From the perspective of the effects of the present invention, the BR content in the rubber component is preferably 30 wt% or more, more preferably 40 wt% or more, even more preferably 50 wt% or more, and particularly preferably 60 wt% or more. Furthermore, although the upper limit of the content is not specifically restricted, it may, for example, be 99 wt% or less, 95 wt% or less, 90 wt% or less, or 85 wt% or less. (BR)

[0086] The type of 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 wt% (a cis-poor BR), a BR with a cis content of 90 wt% 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 types can be combined.

[0087] For example, cis-rich BR can be those commercially available from Zeon Corporation, Ube Industries, Ltd., JSR Corporation, and the like. The inclusion of cis-rich BR can improve abrasion resistance. 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. The cis content of the BR is measured using the method described above.

[0088] Among modified BRs, a BR modified at the end and / or the main chain with a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon, and sulfur can be suitablely used as an ionically modified BR. Examples of the above functional groups include those illustrated by way of example in the modified SBR.

[0089] Examples of other modified BRs include those obtained by adding a tin compound after polymerizing 1,3-butadiene with a lithium initiator, the end of which is further bonded by a tin-carbon bond (a tin-modified BR), and the like. Furthermore, the modified BR can be either non-hydrogenated or hydrogenated.

[0090] From the perspective of abrasion resistance performance, the weight-average molecular weight (Mw) of the BR is preferably 300,000 or more, more preferably 350,000 or more, and even more preferably 400,000 or more. Furthermore, from the perspective of crosslinking uniformity, the weight-average molecular weight is preferably 2,000,000 or less, and more preferably 1,000,000 or less. The Mw of the BR is measured using the measurement method described above.

[0091] To ensure abrasion resistance, the content of BR in the rubber component is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, and particularly preferably 10% by mass or more. Furthermore, to achieve the effect of the present invention, the content of the component is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less. (Other rubber components)

[0092] The rubber component may contain other rubber components (non-diene rubbers) besides the diene-based rubber, within a range that does not affect the effect of the present invention. The non-diene rubber may be a rubber component commonly used in the tire industry, and examples include butyl-based rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, and the like. These other rubber components may be used alone, or two or more types may be used in combination. In addition to the rubber components described above, a known thermoplastic elastomer may or may not be included. (Rubber component synthesized from raw material derived from recycling or biomass)

[0093] A monomer that is a constituent unit of a synthetic rubber, such as IR, BR, or SBR, can be derived from underground resources, such as petroleum and natural gas, or it can be recycled from a rubber product, such as a tire, or from a non-rubber product, such as polystyrene. There are no particular restrictions on the monomer (recycled monomer) obtained through recycling, and examples include recycled polyisoprene, recycled butadiene, and a recycled aromatic vinyl compound. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl compound is not particularly restricted, and examples include styrene.Among these, it is preferred to use as the raw material polyisoprene derived from recycling (recycled isoprene), butadiene derived from recycling (recycled butadiene), and styrene derived from recycling (recycled styrene).

[0094] The process for producing the recycled monomer is not particularly restricted, and examples include a process in which the recycled monomer is synthesized from recycled naphtha obtained by decomposing a rubber product, such as a tire. Furthermore, the process for producing recycled naphtha is not particularly restricted, and, for example, a rubber product, such as a tire, can be decomposed under high temperature and pressure, can be decomposed using a microwave oven, or can be extracted after mechanical pulverization.

[0095] Furthermore, the monomer, which is a constituent unit of a synthetic rubber such as IR, BR, and SBR, can be derived from biomass. In this description, biomass refers to material derived from a natural resource, such as a plant. The definition of biomass is not particularly restricted, and examples include agricultural, forestry, and fishery products; sugar; wood waste; plant residues after extraction of useful components; plant-derived ethanol; biomass aphtha; and the like.

[0096] The biomass-derived monomer (biomass monomer) is not particularly restricted, and examples include biomass-derived butadiene and biomass-derived aromatic vinyl compounds. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl compound is not particularly restricted, and examples include styrene. Furthermore, the process for producing the biomass monomer is not particularly restricted, and examples include biological and / or chemical and / or physical conversion of animals and plants. Fermentation by a microorganism is typical for biological conversion, and conversion by a catalyst, high temperature, high pressure, electromagnetic waves, a critical fluid, and a combination thereof is typical for chemical and / or physical conversion.

[0097] The polymer synthesized from the biomass monomer component (biomass polymer) is not particularly restricted, and examples include a polybutadiene rubber synthesized from biomass-derived butadiene, an 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 copolymers include a styrene butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0098] Whether the raw material of the polymer is derived from biomass or not can be determined by pMC (Percent Modern Carbon), which is measured in accordance with D6866-10.

[0099] The pMC is a ratio of 14 C concentration of a sample to a 14 The carbon concentration of a modern standard reference is a value used as an index indicating the biomass fraction of a compound. The meaning of this value is described below.

[0100] One mole of carbon atoms (6.02 × 10 23 carbon atoms) contains approximately 6.02 × 10 11 14 C atoms, which are approximately one trillionth the number of normal carbon atoms. The half-life of 14 Carbon-14 has a lifespan of 5730 years, and its number decreases regularly. Decay of all 14 Carbon atoms require 226,000 years to form. Therefore, in the case of fossil fuels, such as coal, oil, and natural gas, where it is assumed that 226,000 years or more have passed since carbon dioxide and similar substances were absorbed and fixed in the air, plants, and the like, all 14 Carbon atoms that were initially present in these materials decay. Therefore, fossil fuels, such as coal, oil, and natural gas, contain no carbon atoms in the current 21st century. 14 Carbon atoms. Therefore, chemical materials produced from such fossil fuel raw materials also contain no carbon atoms. 14 Carbon atoms.

[0101] On the other hand 14 C is constantly produced by carrying out a nuclear reaction of cosmic rays in the atmosphere. For this reason, the 14 Carbon reduction due to radioactive decay with the 14 Carbon production due to nuclear reactions is balanced, and the amount of carbon in the global atmosphere is 14 C is constant. Therefore, the 14 Carbon concentration in materials derived from biomass resources released into circulation in the current environment, as described above, is approximately 1 × 10 -12 Molar percent of the total carbon atoms. Therefore, the biomass content in a compound can be calculated using the difference between these values.

[0102] This 14 C is generally measured as follows. Using tandem accelerator mass spectrometry, which is 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 measurement, the 14 C concentration in the natural carbon cycle in 1950 as a modern standard reference, that is, a 14 C standard concentration is used. An oxalic acid standard provided by the National Institute of Standards and Technology (NIST), United States, is used as the specific standard material. The specific radioactivity of carbon (intensity of radioactivity of 14 The carbon (¹³C per gram of carbon) in oxalic acid is separated for isotopic fractionation of carbon, corrected to a specific value, and then adjusted for decay between 1950 AD and the measurement date. This corrected value is called a 14 A standard concentration of 100% of C is used. The ratio of this value to the value of the actual measured sample is the pMC value.

[0103] Accordingly, although there are some differences, such as regional variations, a rubber made entirely from biomass-derived materials is expected to have a pMC value of approximately 110, since such materials often fail to achieve a value of 100 under typical conditions. On the other hand, in a case where the 14 When measuring the carbon concentration of chemical materials derived from fossil fuels, such as petroleum, the expected value is essentially 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%, as described above.

[0104] Based on the above, with regard to environmental protection, it is preferable to use a material in the rubber composition, such as rubber with a high pMC value, that is, a material such as rubber with a high biomass content. <Füllstoff>

[0105] The rubber composition according to the present embodiment contains a filler. The filler according to the present embodiment preferably contains silicon dioxide, more preferably contains carbon black and silicon dioxide, and can be a filler consisting only of carbon black and silicon dioxide. (Silicon dioxide)

[0106] 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 raw material for silicon dioxide is not particularly restricted, and, for example, a mineral-derived raw material such as quartz, a bio-derived raw material such as rice husks (for example, silicon dioxide obtained by using a biomass material such as rice husks as a feedstock), or recycled silicon dioxide from a product containing silicon dioxide can be used. 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 types of it can be used in combination.

[0107] The silicon dioxide obtained by using a biomass material as a raw material can be obtained by extracting silicate from rice hull ash obtained by burning rice hulls, using a sodium hydroxide solution, and by filtering, washing with water, drying and pulverizing precipitates of silicon dioxide produced by using and reacting the silicate with sulfuric acid in the same way as for wet silicon dioxide in the prior art.

[0108] For example, silicon dioxide recycled from a product containing silicon dioxide can be silicon dioxide recovered from products containing silicon dioxide, such as electronic components (e.g., semiconductors), tires, desiccants, filter materials (e.g., diatomaceous earth), or the like. Furthermore, the method for recovering the silicon dioxide is not particularly restricted, and examples include pyrolysis, decomposition by electromagnetic waves, and the like. Among these, silicon dioxide recovered from an electronic component (e.g., a semiconductor) or from a tire is preferred.

[0109] When silicon dioxide crystallizes, it is insoluble in water, and silicic acid, a component of it, cannot be used. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silicon dioxide in rice hull ash (see Japanese unexamined patent publication no. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222, and similar publications).

[0110] The amorphous silicon dioxide extracted from rice husks can be those commercially available from Wilmar International Ltd. and the like.

[0111] The specific nitrogen adsorption surface area (N2SA) of the silicon dioxide is preferably 110 m² from the perspective of reinforcement, fracture strength and abrasion resistance. 2 / g or more, preferably 130 m 2 / g or more, preferably 150 m 2 / g or more and especially preferably 170 m 2 / g or more. Furthermore, from the perspective of heat generation and process efficiency, a specific nitrogen adsorption surface area of ​​350 m² is preferred. 2 / g or less, preferably 300 m 2 / g or less and preferably 250 m 2 / g or less. The N2SA of silicon dioxide is measured using the measurement method described above.

[0112] The average primary particle diameter of the silicon dioxide, from the perspective of suppressing heat generation by increasing the specific surface area of ​​the silicon dioxide and increasing the interaction with the rubber component to suppress molecular chain movement, is 20 nm or less, preferably 19 nm or less, more preferably 18 nm or less, and particularly preferably 17 nm or less. The lower limit of the average primary particle diameter is not particularly restricted and, from the perspective of the dispersibility of silicon dioxide, is preferably 1 nm or more, more preferably 3 nm or more, and still more preferably 5 nm or more. The average primary particle diameter of the silicon dioxide is measured by the measurement method described above.

[0113] For reinforcement purposes, the silicon dioxide content per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, further preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 60 parts by mass or more. Furthermore, for the purpose of improving process efficiency and achieving weight reduction of the rubber, the silicon dioxide content is preferably 200 parts by mass or less, further preferably 160 parts by mass or less, even more preferably 120 parts by mass or less, and particularly preferably 100 parts by mass or less. (Soot)

[0114] Carbon black is not particularly restricted, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, and the like. The raw material for the carbon black can be a biomass material, such as lignin or vegetable oil, or it can be pyrolysis oil obtained by the pyrolysis of a used tire. Furthermore, the process for producing the carbon black can be a combustion process, such as a furnace process, a hydrothermal carbonization (HTC) process, or a thermal carbon black process involving the pyrolysis of methane. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan KK, Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Chemical & Material Co., Ltd., Columbia Carbon Inc., and the like. These carbon blacks can be used alone, or two or more types of them can be used in combination.

[0115] In addition to the above, from the perspective of a life cycle assessment, soot can be soot obtained by using a biomass material, such as lignin, as a raw material, or recycled soot obtained by pyrolyzing and cleaning a product containing soot, such as a tire.

[0116] In this description, "recycled carbon black" refers to carbon black obtained by pulverizing a product, such as a used tire containing carbon black or 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 loss due to the oxidative combustion of the recycled carbon black is 87% by mass or less. Recycled carbon black is sometimes also expressed as rCB.

[0117] The recycled carbon black can be obtained from a pyrolysis process of a used pneumatic tire. European patent application publication No. 3427975, for example, discloses “Rubber Chemistry and Technology”, vol. 85, no. 3, pp. 408-449 (2012), in particular pages 438, 440 and 442, and describes that recycled carbon black can be obtained by pyrolysis of an organic material at 550 °C to 800 °C in an oxygen-free environment or by vacuum pyrolysis at a relatively low temperature (

[0027] ). As described in

[0004] of Japanese patent no. 6856781, such carbon black obtained by the pyrolysis process normally lacks a functional group on its surface (A Comparison of Surface Morphology and Chemistry of Pyrolytic Carbon Blacks with Commercial Carbon Blacks, Powder Technology 160 (2005) 190-193).

[0118] The recycled carbon black can be carbon black lacking a functional group on its surface, or it can be treated to contain a functional group on its surface. This treatment can be carried out using a conventional method. For example, European patent application No. 3173251 describes carbon black obtained from a pyrolysis process being treated with potassium permanganate under acidic conditions, resulting in carbon black containing a hydroxyl group and / or a carboxyl group on its surface. Furthermore, Japanese patent No. 6856781 describes carbon black obtained from a pyrolysis process being treated with an amino acid compound containing at least one thiol group or disulfide group, resulting in carbon black with an activated surface.Examples of recycled carbon black according to the present embodiment also include carbon black that has been treated to contain a functional group on its surface.

[0119] The recycled carbon black used can be that which is commercially available from Strable Green Carbon Pte Ltd., LDC Co., Ltd. and the like.

[0120] The specific nitrogen adsorption surface area (N2SA) of the carbon black is preferably 50 m². 2 / g or more, preferably 80 m 2 / g or more and preferably 100 m 2 / g or more, considering weather resistance and reinforcement. Furthermore, the specific surface area is preferably 250 m², considering dispersibility, fuel efficiency, crushing properties, and durability. 2 / g or less, preferably 220 m 2 / g or less and even more preferably 190 m 2 / g or less. The N2SA of the soot is measured using the measurement method described above.

[0121] The average primary particle diameter of the carbon black is preferably 32 nm or less, more preferably 28 nm or less, even more preferably 26 nm or less, and particularly preferably 22 nm or less. Furthermore, the average primary particle diameter is preferably 8 nm or more, more preferably 10 nm or more, even more preferably 12 nm or more, and particularly preferably 14 nm or more. The average primary particle diameter of the carbon black is measured using the measurement method described above.

[0122] The carbon black content per 100 parts by mass of the rubber component, in a case where carbon black is included, is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, from the point of view of weather resistance and reinforcement. Furthermore, from the point of view of fuel efficiency performance, the carbon black content is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. (Other fillers)

[0123] Fillers other than silicon dioxide and carbon black are not particularly restricted, and those commonly used in the prior art of the tire industry, such as aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, magnesium sulfate, talc, clay, biochar, and the like, are permitted. These other fillers can be used alone, or two or more fillers can be used in combination.

[0124] The ratio of carbon black to silicon dioxide content is preferably 0.40 or less, more preferably 0.33 or less, even more preferably 0.25 or less, still more preferably 0.20 or less, and most preferably 0.15 or less. Fuel efficiency can be further improved by adjusting the carbon black to silicon dioxide ratio within the range described above. On the other hand, the lower limit of the carbon black to silicon dioxide ratio is not particularly restricted. For example, the ratio can be 0.01 or more, 0.02 or more, or 0.05 or more, and the filler may not contain carbon black.

[0125] The total filler content, based on 100 parts by mass of the rubber component, is 45 parts by mass or more, preferably 55 parts by mass or more, more preferably 65 parts by mass or more, and even more preferably 70 parts by mass or more, to ensure reinforcement when dry. Furthermore, to improve fuel efficiency and process efficiency, the content is preferably 200 parts by mass or less, more preferably 160 parts by mass or less, even more preferably 120 parts by mass or less, and most preferably 100 parts by mass or less. (Silane coupling agent)

[0126] In a case where silicon dioxide is used, it is preferred to use a silane coupling agent in combination. The silane coupling agent is not particularly restricted, and examples include sulfide-based silane coupling agents, such as bis(3-triethoxysilylpropyl)disulfide and bis(3-triethoxysilylpropyl)tetrasulfide; mercapto-based silane coupling agents, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane; and vinyl-based silane coupling agents, such as vinyltriethoxysilane and vinyltrimethoxysilane. Amino-based silane coupling agents, such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane; glycidoxy-based silane coupling agents, such as glycidoxypropyltriethoxysilane and glycidoxypropyltrimethoxysilane;Nitro-based silane coupling agents, such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; chlorine-based silane coupling agents, such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane; quaternary ammonium salt-based silane coupling agents, such as water-based silane coupling agents with a quaternary ammonium salt in the organic functional group;and the like. Among these, an amino-based silane coupling agent, a glycydoxy-based silane coupling agent, and a quaternary ammonium salt-based silane coupling agent can be suitable as the ionically bound silane coupling agents. For example, those commercially available from Evonik Degussa GmbH, Momentive Performance Materials, Shin-Etsu Chemical Co., Ltd., Topco Technologies Corporation, or similar companies can be used as the silane coupling agents. These silane coupling agents can be used alone, or two or more types can be used in combination.

[0127] The content of the silane coupling agent per 100 parts by mass of silicon dioxide is preferably 1.0 parts by mass or more, more preferably 3.0 parts by mass or more, even more preferably 5.0 parts by mass or more, and particularly preferably 7.0 parts by mass or more, to enhance the dispersibility of silicon dioxide. Furthermore, to optimize cost and process efficiency, the content of the silane coupling agent is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less. <Andere Verbindungsmittel>

[0128] The rubber composition according to the present embodiment may suitably comprise bonding agents commonly used in the tire industry in the prior art, such as a plasticizer, vulcanized rubber particles, a processing aid, a wax, an antioxidant, stearic acid, zinc oxide, a vulcanizing agent, a vulcanization accelerator and the like, in addition to the components described above.

[0129] A plasticizer is a material that imparts plasticity to the rubber component and is a concept encompassing both liquid plasticizers at 25°C and solid plasticizers at room temperature (25°C). Examples of plasticizers include resin components, oils, liquid polymers, ester-based plasticizers, and the like. These plasticizers can be derived from mineral resources such as petroleum or natural gas, from biomass, or from naphtha recycled from rubber or non-rubber products. Additionally, a low-molecular-weight hydrocarbon component obtained by pyrolysis and extraction from a used tire or a product containing various components can be used as a plasticizer.Among these plasticizers, a plasticizer modified with a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon, and sulfur can be used as a suitable ionically modified plasticizer. These plasticizers can be used alone, or two or more types can be used in combination. (resin component)

[0130] The resin component is not particularly restricted, as long as it is a resin commonly used in the tire industry. Examples include rosin-based resins, terpene-based resins, dicyclopentadiene-based resins, aromatic vinyl resins, C9-based resins, C5-based resins, C5-C9-based resins, phenol-based resins, and the like. Among these, a rosin-based resin can be suitable as the ionically modified resin because it contains a carboxyl group. These resin components can be used individually, or two or more types can be used in combination.

[0131] The term "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 hydrogenated or modified. Rosin-based resins are not particularly restricted, and examples include natural resin rosin, rosin-modified resins obtained by modifying natural resin rosin via hydrogenation, disproportionation, dimerization, esterification, or the like. These rosin-based resins may be used alone, or two or more types may be used in combination.

[0132] Terpene-based resin is a resin containing a terpene compound, such as α-pinene, β-pinene, limonene, or dipentene, as the highest-concentration monomer component and may be hydrogenated or modified. Specific examples of terpene-based resin include a polyterpene resin containing only one or more of the aforementioned terpene compounds as a monomer component; an aromatically modified terpene resin containing the terpene compound and an aromatic compound as monomer components; a terpenophenolic resin containing the terpene compound and a phenol-based compound as monomer components; and the like. Examples of aromatic compounds used as the monomer component of aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, divinyltoluene, and the like.Examples of phenol-based compounds used as the monomer component of terpene phenol resins include phenol, bisphenol A, cresol, xylenol, and the like. These terpene-based resins can be used alone, or two or more types can be used in combination.

[0133] The “dicyclopentadiene-based resin” is a resin containing cyclopentadiene (CPD) or dicyclopentadiene (DCPD) as a monomer component and may be hydrogenated or modified. Examples of dicyclopentadiene-based resins include DCPD / C9 resins containing dicyclopentadiene and a C9 fraction as monomer components (the DCPD / C9 resins may be hydrogenated or modified); a DCPD / C9 resin containing dicyclopentadiene and styrene as monomer components is preferred; and a DCPD / C9 resin containing dicyclopentadiene, styrene, and indene as monomer components is further preferred. Examples of dicyclopentadiene-based resins that may be used include those commercially available from Exxon Mobil Corporation, ENEOS Corporation, Japan Zeon Corporation, Maruzen Petrochemical Co., Ltd., and the like. These dicyclopentadiene-based resins can be used alone, or two or more types of them can be used in combination.

[0134] The “aromatic vinyl-based resin” is a resin containing an aromatic vinyl compound, such as styrene, α-methylstyrene, vinyltoluene, or p-chlorostyrene, as the monomer component with the highest concentration, and may be hydrogenated or modified. An α-methylstyrene or styrene homopolymer or an α-methylstyrene and styrene copolymer is preferred as the aromatic vinyl-based resin because it is economical, easy to process, and has excellent heat generation properties; an α-methylstyrene and styrene copolymer is further preferred. Examples of aromatic vinyl-based resins that may be used include those commercially available from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., and the like. These aromatic vinyl resins may be used alone, or two or more types may be used in combination.

[0135] The term "C9-based resin" refers to a resin obtained by polymerizing a C9 fraction. It can be obtained by polymerizing only a C9 fraction or it can be a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) and a C9 fraction is called a DCPD / C9 resin. Furthermore, a hydrogenated or modified version of this can be used. Examples of C9 fractions include petroleum fractions corresponding to 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumaron, indene, methylindene, and dicyclopentadiene.

[0136] These C9-based resins can be used alone, or two or more types can be used in combination.

[0137] The term "C5-based resin" refers to a resin obtained by polymerizing a C5 fraction and may be hydrogenated or modified. Examples of the C5 fraction include petroleum fractions corresponding to 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene. C5-based resins can be used individually, or two or more types can be used in combination.

[0138] The term "C5-C9-based resin" refers to a resin obtained by polymerizing a C5 fraction and a C9 fraction, and may be hydrogenated or modified. Examples of C5-C9-based petroleum resins include those commercially available from Tosoh Corporation, Zibo Luhua Hongjin New Material Co., Ltd., and similar companies. These C5-C9-based resins can be used alone, or two or more types can be used in combination.

[0139] The term "phenol-based resin" refers to a resin containing a phenol compound, such as phenol and cresol, as the monomer component with the highest concentration. Phenol-based resins are not particularly limited in their range, and examples include phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, oil-modified phenol-formaldehyde resins, and the like. These phenol-based resins can be used individually, or two or more types can be used in combination.

[0140] 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 process efficiency and improved dispersibility of the rubber component and the filler, the temperature is preferably 150 °C or lower, more preferably 140 °C or lower, and even more preferably 130 °C or lower. The softening point of the resin component is measured using the measurement method described above.

[0141] In a case where the resin component is included, the content of the resin component, in relation to 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 12 parts by mass or more. Furthermore, with regard to suppressing heat generation, the content 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. (Oil)

[0142] Examples of oil include mineral oils, vegetable oils, animal oils, and the like. Furthermore, from a life cycle assessment perspective, used oil can be reused after use in a rubber mixer or an engine, or a refined product can be derived from used cooking oil used in a restaurant.

[0143] In this description, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffin-based oils, naphthene-based oils, aromatic oils, and the like. Specific examples of mineral oil include mild extraction solvents (MES), distillate aromatic extracts (DAE), treated distillate aromatic extracts (TDAE), treated residual aromatic extracts (TRAE), residual aromatic extracts (RAE), and the like. Additionally, as an environmental measure, oils with a low polycyclic aromatic compound (PCA) content may be used. Examples of low PCA oils include MES, TDAE, and heavy naphthene-based oils, and the like.

[0144] In the present description, examples of "vegetable oil" include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, paulownia 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, vegetable wax, and the like. Examples of vegetable oil also include a refined oil (cooking oil or the like) obtained by refining the oil, a transesterified oil obtained by transesterifying the oil, a hydrogenated oil obtained by hydrogenating the oil, a thermally polymerized oil obtained by thermally polymerizing the oil, an oxidatively polymerized oil obtained by oxidatively polymerizing the oil, a used cooking oil recovered from an oil that has been used as a cooking oil, and the like.The vegetable oil can be a liquid or a solid at room temperature (25°C). These vegetable oils can be used alone, or two or more types can be used in combination.

[0145] The vegetable oil according to the present embodiment preferably contains acylglycerol and further preferably contains triacylglycerol. In this description, acylglycerol refers to a compound in which a hydroxyl group of glycerol and a fatty acid are ester-bound. Acylglycerol is not particularly restricted and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, a trimer, or a higher polymer. In addition, acylglycerol that is a dimer or higher polymer may be obtained by thermal polymerization, oxidative polymerization, and the like. Furthermore, acylglycerol may be a liquid or a solid at room temperature (25 °C).

[0146] As a method for checking whether the rubber composition contains acylglycerol, the test can be carried out, but is not particularly limited to 1 H-NMR measurement below. In particular, a rubber compound bonded to a triacylglycerol is immersed in heavy chloroform at room temperature (25 °C) for 24 hours and removed to 1 When measuring ¹H NMR at room temperature, and in one case where a signal from tetramethylsilane (TMS) is defined as 0.00 ppm, signals close to 5.26 ppm, close to 4.28 ppm, and close to 4.15 ppm are observed, suggesting that the signals are derived from hydrogen atoms bonded to carbon atoms adjacent to oxygen atoms of an ester group. Furthermore, "close" in this paragraph refers to a range of ±0.10 ppm.

[0147] 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. Examples of saturated fatty acids include butyric acid, lauric acid, and the like.

[0148] Among these, the desirable fatty acid should be one with a low number of double bonds, that is, a saturated or monounsaturated fatty acid, with oleic acid being preferred. For example, a vegetable oil containing such a fatty acid can be a saturated or monounsaturated vegetable oil, or a vegetable oil that has undergone modification, such as transesterification, can be used. Furthermore, to produce a vegetable oil containing such a fatty acid, a plant can be improved through breeding, genetic recombination, or similar methods.

[0149] Suitable vegetable oils include, for example, those commercially available from Idemitsu Kosan Co., Ltd., Mitsui Chemicals, Inc., ENEOS Corporation, Oleon NV., H&R ChemPharm (UK) Ltd., Hokoku Corporation, Fuji Kosan Company, Ltd., The Nisshin OilliO Group, Ltd. and the like.

[0150] Examples of animal oil include fish oil, beef tallow, oleyl alcohol derived from these, and the like.

[0151] The oil content (total quantity of several oils in a case where several oils are used in combination) per 100 parts by mass of the rubber component is, from the point of view of process efficiency, preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 12 parts by mass or more. Furthermore, from the point of view of the hardness of the rubber, the oil content 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 polymer)

[0152] The liquid polymer is not particularly restricted as long as it is a polymer in a liquid state at room temperature (25 °C), and examples include a liquid butadiene polymer (liquid BR), a liquid isoprene polymer (liquid IR), a liquid styrene-butadiene copolymer (liquid SBR), a liquid styrene-isoprene copolymer (liquid SIR), and a polymer containing myrcene and farnesene. Among these liquid polymers, a liquid polymer modified at the end and / or main chain with a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon, and sulfur may be suitablely used as the ionically modified liquid polymer. Examples of the above functional groups include those illustrated by way of example in the modified SBR. A liquid polymer manufactured by Kuraray Co., Ltd. may also be considered a liquid polymer.is manufactured, and the like is used. These liquid polymers can be used alone, or two or more types of them can be used in combination.

[0153] In a case where the liquid polymer is included, the liquid polymer content, in relation to 100 parts by mass of the rubber component, is preferably 1 part by mass or more, further preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 12 parts by mass or more. Furthermore, the liquid polymer content 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. (Ester-based plasticizers)

[0154] Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di(2-ethylhexyl) azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), and the like. These ester-based plasticizers can be used alone, or two or more types can be used in combination.

[0155] The plasticizer content (the total amount in a case where several plasticizers are used in combination) per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, further preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more. Furthermore, the content is preferably 100 parts by mass or less, further preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, and particularly preferably 50 parts by mass or less.

[0156] In a case where one or more of the rubber component, the silicon dioxide, the resin component and the liquid polymer are modified with a carboxyl group, various metal salts can be combined to form an ionic bond in the rubber composition.Examples of metal salts include metal carbonates, such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate; metal acetates, such as lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate, beryllium acetate, magnesium acetate, calcium acetate, strontium acetate, and barium acetate; fatty acid metal salts other than metal acetates, such as sodium stearate, magnesium stearate, calcium stearate, barium stearate, sodium oleate, magnesium oleate, calcium oleate, and barium oleate; metal phenoxides, such as lithium phenoxide, sodium phenoxide, potassium phenoxide, rubidium phenoxide, cesium phenoxide, beryllium diphenoxide, magnesium diphenoxide, calcium diphenoxide, strontium diphenoxide, and barium diphenoxide; and the like.

[0157] The content of the metal salt per 100 parts by mass of the rubber component is preferably 1 part by mass or more, further preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more. Furthermore, the content is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 12 parts by mass or less. (Vulcanized rubber particles)

[0158] Vulcanized rubber particles are particles that contain vulcanized rubber as a material, and in particular, rubber powder and the like, as defined in JIS K 6316:2017, may be used. Recycled rubber powder produced from a powdered end-of-life tire or the like is preferred from the perspective of environmental compatibility and cost. These may be used alone, or two or more types may be used in combination.

[0159] The vulcanized rubber particles are not particularly restricted and can be unmodified or modified vulcanized rubber particles. For example, commercially available vulcanized rubber products from Lehigh Technologies, Inc., MURAOKA RUBBER RECLAIMING Co., Ltd., and similar companies can be used.

[0160] The content of vulcanized rubber particles in relation to 100 parts by mass of the rubber component in a case where the vulcanized rubber particles are included can be appropriately adjusted in a range of, for example, more than 1 part by mass and less than 80 parts by mass. (Processing aids)

[0161] Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silicon dioxide surfactants, fatty acid esters, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. Processing aids that can be used include, for example, those commercially available from Schill + Seilacher GmbH, Performance Additives Ltd., and similar companies. These processing aids can be used individually, or two or more types can be used in combination.

[0162] In a case where the processing aid is included, the content of the processing aid per 100 parts by mass of the rubber component, with regard to demonstrating an improvement in process efficiency, is preferably more than 0.5 parts by mass, more preferably more than 1 part by mass, and even more preferably more than 1.5 parts by mass. Furthermore, with regard to abrasion resistance and fracture toughness, the content of the processing aid is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and even more preferably less than 5.0 parts by mass. (Wax)

[0163] The wax is not particularly restricted, and any wax commonly used in the tire industry can be used appropriately. Examples of wax include mineral waxes and plant-derived waxes. Mineral wax refers to a wax derived from a mineral resource, such as oil or natural gas. Plant-derived wax refers to a wax derived from a natural resource, such as a plant. Among these, mineral waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, and the like. Examples of mineral wax include paraffin wax, microcrystalline wax, specially selected waxes thereof, and the like, with paraffin wax being preferred. The wax according to the present embodiment does not contain stearic acid. For example, those waxes available from Ouchi Shinko Chemical Industrial Co. can be used.These waxes are commercially available from companies such as Nippon Seiro Co., Ltd., Paramelt BV, and similar firms. They can be used alone, or two or more types can be used in combination.

[0164] In a case where wax is included, from the perspective of the weather resistance of the rubber, the wax content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more. Furthermore, from the perspective of preventing the tire from whitening due to blooming, the wax content is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. (Antioxidants)

[0165] The antioxidant is not particularly restricted, and examples include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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) and N,N'-di-2-naphthyl-p-phenylenediamine (DNPDA); quinoline-based antioxidants, such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline; Monophenol-based antioxidants, such as 2,6-di-t-butyl-4-methylphenol and styrenized phenol;Bisphenol-, trisphenol-, 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 N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline are further preferred. Commercial products such as those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industrial Co., Ltd., Flexsys, and the like may be used. These antioxidants may be used individually, or two or more types may be used in combination.

[0166] The antioxidant content per 100 parts by mass of the rubber component, when the antioxidant is present, 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 the rubber. Furthermore, with regard to abrasion resistance, the antioxidant content is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0167] In a case where stearic acid is included, the stearic acid content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of process efficiency. Furthermore, from the point of view of vulcanization rate, the stearic acid content is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0168] In a case where zinc oxide is included, the zinc oxide content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of process efficiency. Furthermore, the antioxidant content, from the point of view of abrasion resistance, is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less. (Vulcanizing agent)

[0169] Sulfur is suitable for use as a vulcanizing agent. The sulfur used can be powdered, oil-processing, precipitated, colloidal, insoluble, highly dispersible, or similar.

[0170] In a case where sulfur is included as the vulcanizing agent, the sulfur content per 100 parts by mass of the rubber component is preferably more than 0.1 parts by mass, more preferably more than 0.5 parts by mass, and even more preferably more than 1.0 parts by mass, to ensure a sufficient vulcanization reaction. Furthermore, to prevent deterioration, the sulfur content is preferably less than 5.0 parts by mass, more preferably less than 4.0 parts by mass, and even more preferably less than 3.5 parts by mass. Moreover, to achieve the effect of the present invention, the vulcanizing agent content is preferably 3.0 parts by mass or less, more preferably less than 2.5 parts by mass, even more preferably less than 2.0 parts by mass, and particularly preferably 1.5 parts by mass or less, in order to reduce the density of sulfur crosslinking.In a case where an oil-containing sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is the total content of pure sulfur contained in the oil-containing sulfur.

[0171] Examples of vulcanizing agents other than sulfur include alkylphenol sulfur chloride condensate, sodium hexamethylene 1,6-bisthiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and the like. These vulcanizing agents, other than sulfur, can be those commercially available from Taoka Chemical Company, Limited, LANXESS, Flexsys, and similar companies. The vulcanizing agents other than sulfur can be used alone, or two or more types can be used in combination. (Vulcanization accelerator)

[0172] Examples of vulcanization accelerators include sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiuram-based vulcanization accelerators, dithiocarbamic acid salt-based vulcanization accelerators, and caprolactam disulfide. These vulcanization accelerators can be used individually, or two or more types can be used in combination.From the perspective that a desired effect is obtained more appropriately, one or more vulcanization accelerators selected from the group consisting of a sulfenamide-based vulcanization accelerator, a thiazole-based vulcanization accelerator and a guanidine-based vulcanization accelerator are preferred, and it is further preferred to use a sulfenamide-based vulcanization accelerator and a guanidine-based vulcanization accelerator in combination.

[0173] Examples of sulfenamide-based vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like. Among these, TBBS and CBS are preferred.

[0174] Examples of thiazole-based vulcanization accelerators include 2-mercaptobenzothiazole (MBT) or a salt thereof, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, and the like. Among these, MBTS and MBT are preferred, and MBTS is further preferred.

[0175] Examples of guanidine-based vulcanization accelerators include 1,3-diphenylguanidine (DPG), 1,3-diotolylguanidine, 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. Of these, DPG is preferred.

[0176] In a case where the vulcanization accelerator is included, the content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more. Furthermore, the content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, and even more preferably 4.0 parts by mass or less. By adjusting the content of the vulcanization accelerator within the above range, there is a tendency to ensure fracture toughness and elongation.

[0177] In the present description, various materials (for example, rubber, oil, resin components, vulcanization accelerators, antioxidants, and the like) containing a carbon atom can be derived from carbon dioxide present in the atmosphere. As a method for obtaining these various materials from carbon dioxide, the carbon dioxide can be converted directly, or the methane obtained through a methanation process—the synthesis of methane from carbon dioxide—can be converted. [Production of rubber compound and tires]

[0178] The rubber composition according to the present embodiment can be produced by a known method. For example, the rubber composition 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, and the like (Bunbury mixer, kneader, or the like).

[0179] The kneading process includes, for example, a basic kneading process involving the kneading of a bonding agent and an additive other than a vulcanizing agent and a vulcanization accelerator, and a final kneading process (F-kneading) involving the addition of a vulcanizing agent and a vulcanization accelerator to the kneaded product obtained from the basic kneading process and the kneading of these materials. Furthermore, the basic kneading process can be subdivided into several processes as required.

[0180] The kneading conditions are not particularly restricted, but examples include a kneading process at a discharge temperature of 150 °C to 170 °C for 3 to 10 minutes for the initial kneading step and a kneading process at 70 °C to 110 °C for 1 to 5 minutes for the final kneading step. Vulcanization conditions are not particularly restricted, and examples include a vulcanization process at 150 °C to 200 °C for 10 to 30 minutes.

[0181] The tire of the present invention, which includes a tread formed from the rubber composition, can be produced by a conventional method. That is, the tire can be produced by extruding an unvulcanized rubber composition, which is made from the rubber component and each of the components described above as required, into a mold for a first layer of the tread, by joining the rubber composition with the inner rubber layer of the tread and other tire elements on a tire molding machine, and by forming these materials by a conventional method to create an unvulcanized tire, followed by heating and pressurizing this unvulcanized tire in a vulcanizing machine.Vulcanization conditions are not particularly restricted, and examples include a vulcanization process at 150 °C to 200 °C for 10 to 30 minutes. [Application of tires]

[0182] The tire according to the present embodiment can be used as a tire for a passenger car, a tire for a truck and bus, a tire for a two-wheeled vehicle, and a racing tire, and among these, the tire is preferably used as a tire for a passenger car. A tire for a passenger car is a tire intended to be mounted on a four-wheeled automobile and refers to a tire having a maximum load capacity of 1,400 kg or less. [Examples]

[0183] Examples (examples) considered preferred in the implementation of the present embodiment are described below. However, the scope of protection of the present invention is not limited to these examples. A tire with a first layer of a tread section obtained in accordance with the compound of Table 1 is tested using various chemicals shown below, and the results calculated on the basis of the following evaluation methods are shown in Table 1.

[0184] Below is a collective list of various chemicals used in examples and comparisons. NR: TSR20 SBR1: Nipol NS616 (S-SBR, styrene content: 21 wt%, vinyl content: 61 mol%, Mw: 510,000, non-oil-extended), manufactured by ZS Elastomer Co., Ltd. SBR2: SBR (SBR modified by carboxylic acid, carboxylic acid group content: 5 wt%, styrene content: 23 wt%, and butadiene content: 72 wt%), produced by the following production example 1 BR1: Nipol BR1220 (BR, synthesized using a cobalt-based catalyst, cis content: 96 mol%, Mw: 460,000, manufactured by Zeon Corporation Soot: SEAST 6 (N2SA: 119 m 2 / g, average primary particle diameter: 22 nm), manufactured by Tokai Carbon Co., Ltd. Silicon dioxide 1: ULTRASIL (registered trademark) VN3 (N2SA: 175 m 2 / g, average primary particle diameter: 17 nm), manufactured by Evonik Degussa GmbH Silicon dioxide 2: ULTRASIL (registered trademark) 9100GR (N2SA: 235 m 2 / g, average primary particle diameter: 15 nm), manufactured by Evonik Degussa GmbH Silane coupling agent 1: Si266 (Bis(3-triethoxysilylpropyl)disulfide), manufactured by Evonik Degussa GmbH Silane coupling agent 2 (ionically bound silane coupling agent): KBE603 (N-2-(Aminoethyl)-3-aminopropyltriethoxysilane), manufactured by Topco Technologics Corporation Liquid polymer (ionically bonded polymer): LIR 410 (approximately 10 carboxyl groups per molecule, modified liquid polyisoprene with an average molecular weight of 25,000), manufactured by Kuraray Co., Ltd. Oil: Process X-140, manufactured by ENEOS Corporation Resin component 1: SYLVATRAXX 4150 (polyterpene resin, softening point: 115 °C), manufactured by Kraton Corporation Resin component 2: Rosin resin, manufactured by Sigma-Aldrich Company Limited Metal salt: Potassium acetate Zinc oxide: Zinc oxide No. 1, manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Stearic acid “Tsubaki”, manufactured by NOF Corporation Wax: SUNNOC N (paraffin wax), manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Antioxidant: Nocrac 6C (N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine), manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Sulfur: Powdered sulfur, manufactured by Karuizawa Sulfur Co., Ltd. Vulcanization accelerator 1: Nocceler D (1,3-Diphenylguanidine (DPG)), manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Vulcanization accelerator 1: Nocceler NS-G (N-tert-Butyl-2-benzothiazole sulfenamide (TBBS)), manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. (Production example 1: Production of SBR2)

[0185] Distilled water, an emulsifier (1), an emulsifier (2), an electrolyte, styrene, methacrylic acid, butadiene, and a molecular weight regulator are placed in a pressure-resistant reactor equipped with a stirrer. An aqueous solution containing a radical initiator and SFS, and an aqueous solution containing EDTA and a catalyst, are added to the reactor to initiate polymerization. A polymerization terminator is then added to stop the reaction, yielding a latex. Unreacted monomers are removed by steam distillation. The residue is added to alcohol and coagulated while being adjusted to pH 3–5 with a saturated aqueous solution of sodium chloride or formic acid. A granular polymer is then obtained. The granular polymer is subsequently dried in a vacuum dryer to yield SBR2.

[0186] The materials used in production example 1 are as follows. Emulsifier (1): Rosin soap, manufactured by Harima Chemicals, Inc. Emulsifier (2): Fatty acid soap, manufactured by FUJIFILM Wako Pure Chemical Corporation Electrolyte: Sodium phosphate, manufactured by FUJIFILM Wako Pure Chemical Corporation Styrene: Styrene manufactured by FUJIFILM Wako Pure Chemical Corporation Methacrylic acid: Methacrylic acid, manufactured by FUJIFILM Wako Pure Chemical Corporation Butadiene: 1,3-Butadiene, manufactured by Takachiho Chemical Industrial Co., Ltd. Molecular weight regulator: Tert-dodecyl mercaptan, manufactured by FUJIFILM Wako Pure Chemical Corporation Radical initiator: Paramenthyl hydroperoxide, manufactured by NOF Corporation SFS: Sodium formaldehyde sulfoxylate, manufactured by Fujifilm Wako Pure Chemical Corporation EDTA: Sodium ethyldiaminetetraacetate, manufactured by FUJIFILM Wako Pure Chemical Corporation Catalyst: Ferrous sulfate, manufactured by FUJIFILM Wako Pure Chemical Corporation Polymerization terminator: N,N'-Dimethyldithiocarbamate, manufactured by FUJIFILM Wako Pure Chemical Corporation Alcohol: Methanol and ethanol, manufactured by Kanto Chemical Co., Inc. Formic acid: Formic acid manufactured by Kanto Chemical Co., Inc. Sodium chloride: Sodium chloride, manufactured by FUJIFILM Wako Pure Chemical Corporation (Examples and comparisons)

[0187] According to the compound formulations shown in Table 1, chemicals other than sulfur and vulcanization accelerator are kneaded using a 1.7-liter closed-type Banbury mixer for 1 to 10 minutes until the discharge temperature reaches 150 to 160 °C to obtain a kneaded product. Next, using an open twin-screw mixer, sulfur and vulcanization accelerator are added to the kneaded product, and the mixture is kneaded for 4 minutes until the temperature reaches 105 °C to obtain an unvulcanized rubber composition.The unvulcanized rubber compound is used to extrude a first layer (thickness: 10 mm) of tread section into a mold using an extruder equipped with a die of a predetermined shape. This layer is then joined with a second layer (thickness: 4 mm) of the tread section and other tire elements to produce an unvulcanized tire. The unvulcanized tire is then press-vulcanized at 170 °C for 12 minutes to produce each test tire (size: 195 / 65R15, rim: 15 × 6 JJ, internal pressure: 230 kPa) as described in Table 1. <Messung von Viskoelastizität>

[0188] Each vulcanized rubber test piece, produced by cutting a 20 mm long, 4 mm wide, and 1 mm thick section from the inside of the first layer of the tread section of each test tire, such that the tire's circumferential direction becomes a long side and the tire's radial direction a thickness direction, is immersed in water at 25 °C for 12 hours to obtain a water-wetted vulcanized rubber compound. A dynamic viscoelasticity measuring device (EPLEXOR series, manufactured by GABO) is used to measure the 30 °C* thickness of this water-wetted vulcanized rubber compound. W and 30 °C tanδ W The elongation is measured under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 1%, and a specific strain mode. Next, the vulcanized rubber composition, after wetting with water, is dried under reduced pressure at 80 °C and 1 kPa or less until its weight becomes constant, resulting in a vulcanized rubber composition after drying. The vulcanized rubber composition after drying is then tested for 30 °C*. D and 30 °C tanδ D measured under the conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ± 1% and a strain mode using a dynamic viscoelasticity measuring device (EPLEXOR series, manufactured by GABO). <Messung von Glasübergangstemperatur (Tg) von Kautschukzusammensetzung>

[0189] For each vulcanized rubber test piece, produced by cutting a 20 mm long, 4 mm wide, and 1 mm thick sample from a tread section of each test tire such that the tire's circumferential direction becomes a long side and the tire's radial direction becomes the thickness direction, a temperature distribution curve of tanδ in a range of -60 °C or higher and 40 °C or lower is measured using a dynamic viscoelasticity measuring device (EPLEXOR series, manufactured by GABO) under conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a temperature rise rate of 2 °C / min, and a temperature (tanδ peak temperature) corresponding to a maximum tanδ value in the obtained temperature distribution curve is determined as Tg of the rubber composition. <Messung von Menge an Schwefel>

[0190] For each vulcanized rubber test piece produced by cutting a 20 mm long, 4 mm wide and 1 mm thick test piece from the inside of the first layer of the tread section of each test tire such that the tire circumferential direction becomes a long side and the tire radial direction is a thickness direction, the amount of sulfur (mass %) is measured by an oxygen combustion piston method in accordance with JIS K 6233: 2016. <nasshaftungsleistung>

[0191] Each test tire is loaded on all wheels of a vehicle (domestically produced FF2000cc), and a braking distance is measured from the point where the brakes are applied at a speed of 100 km / h on a wet asphalt road surface. The braking distance of a reference tire (Comparison Example 1) is converted to 100, and the reciprocal of each test tire's braking distance is expressed as an index according to the following formula. The higher the index, the better the wet grip performance. (Wet grip performance index) = (Braking distance of reference tires) / (Braking distance of each test tire) <trockenhaftungsleistung>

[0192] Each test tire is loaded on all wheels of a vehicle (domestically produced FF2000cc), and a braking distance is measured from the point where the brakes are applied at a speed of 100 km / h on a dry asphalt road surface. The braking distance of a reference tire (Comparison Example 1) is converted to 100, and the reciprocal of each test tire's braking distance is expressed as an index according to the following formula. The higher the index, the better the dry grip performance. (Dry grip performance index) = (Braking distance of reference tires) / (Braking distance of each test tire) <brennstoffeffizienzleistung>

[0193] The rolling resistance of each test tire, when mounted on a 15 x 6 JJ rim, with an internal pressure of 230 kPa, a load of 3.43 kN, and a speed of 80 km / h, is measured using a rolling resistance tester. The reciprocal of this measurement is expressed as an index, with the rolling resistance of the reference comparison example set to 100. The higher the index, the lower the rolling resistance and the better the fuel efficiency performance. <gesamtleistung>

[0194] The sum of the wet adhesion performance index, the dry adhesion performance index and the fuel efficiency performance is expressed as an overall performance index.< / gesamtleistung> < / brennstoffeffizienzleistung> < / trockenhaftungsleistung> < / nasshaftungsleistung> < / kautschukkomponente> < / messverfahren> < / definitionen>

Claims

[1] Tires, including: a tread section that has at least one layer of rubber, wherein a first layer, which forms a tread surface, is formed from a rubber composition containing a rubber component and a filler, the rubber composition contains 45 parts by mass of the filler in relation to 100 parts by mass of the rubber component, and if the maximum load capacity of the tire W L (kg) is a weight of the tire G (kg) is a height ratio at a ground contact area of ​​the tread section R is a complex modulus of elasticity at 30 °C of the rubber composition when dry, 30 °CE* D (MPa) is a complex modulus of elasticity at 30 °C of the rubber composition when wet, 30 °CE* W (MPa) is the tanδ at 30 °C of the rubber composition when dry, 30 °C-tanδ Dis and tanδ at 30 °C of the rubber composition, when water-wet, 30 °C-tanδ W is, W L , G, R, 30 °CE* D , 30 °CE* W , 30 °C-tanδ D and 30 °C tanδ W satisfy the following expressions (1) to (6): R≥0.50 G / WL≤0.025 |30 °C−E*D−30 °C−E*W|≥1.3 |30 °C−tanδD−30 °C−tanδW|≥0.03 |30 °C−E*D−30 °C−E*W|×R≥0.70 |30 °C−tanδD−30 °C−tanδW| / (G / WL)≥1.3 [2] Tire according to claim 1, wherein the rubber composition contains 40 parts by mass or more of silicon dioxide in relation to 100 parts by mass of the rubber component. [3] Tires according to claim 2, wherein an average primary particle diameter of the silicon dioxide is 20 nm or less. [4] Tires according to any one of claims 1 to 3, wherein the rubber composition contains 5 parts by mass or more of a plasticizer in relation to 100 parts by mass of a rubber component. [5] Tires according to claim 4, wherein the plasticizer comprises at least one selected from the group consisting of a resin component and a liquid polymer. [6] Tires according to any one of claims 1 to 5, wherein the rubber component contains 10 wt% or more of a butadiene rubber. [7] Tires according to any one of claims 1 to 6, wherein the amount of sulfur in the rubber composition is 0.1% by mass or more. [8] Tires according to any one of claims 1 to 7, wherein the glass transition temperature of the rubber composition is -10 °C or higher. [9] Tires according to any one of claims 1 to 8, wherein the 30 °CE* D 3.0 MPa or more. [10] Tires according to any one of claims 1 to 9, wherein the 30 °C tanδ D 0.10 or more.