Tire

Abstract

Provided is a tire in which the overall performance of snow performance and wet grip performance is improved. A tire having a tread portion having one or more circumferential grooves, the tread portion comprising a rubber composition containing silica and a rubber component containing an isoprene-based rubber and a styrene butadiene rubber, the rubber component containing silica and an isoprene-based rubber, the silica containing silica and the isoprene-based rubber, and the rubber component containing silica and the isoprene-based rubber. The content of the isoprene rubber in the rubber component is 40% by mass or more, the content of the silica is 70 parts by mass or more with respect to 100 parts by mass of the rubber component, the styrene content S1 (mass%) of the styrene butadiene rubber is 30 or less, and the acetone extraction amount AE (mass%) of the rubber composition is greater than 17.0. The rubber composition is characterized in that the half-peak width of a peak in the range of-20 DEG C to-70 DEG C in a tan [delta] temperature distribution curve of the rubber composition is 45 DEG C or more, the groove depth of the deepest part of the circumferential grooves is set as H (mm), and when the tan [delta] of the rubber composition at-10 DEG C is set as-10 DEG C tan [delta],-10 DEG C tan [delta] * H is 1.7 or more.

Description

Technical Field

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

[0002] Patent Document 1 discloses that a tire having inclined grooves in the tread portion and setting parameters within a specified range provides a tire that equally improves wet grip performance and ice grip performance, and the above parameters are obtained from the van der Waals force when scanning the rubber composition constituting the tread rubber with an atomic force microscope at a specified temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Problems to be Solved by the Invention

[0004] In recent years, further improvement in snow performance and wet grip performance has been desired.

[0005] An object of the present invention is to provide a tire that improves the comprehensive performance of snow performance and wet grip performance.

Means for Solving the Problems

[0006] The present invention relates to a tire, which is a tire having a tread portion, the tread portion having one or more circumferential grooves, the tread portion being composed of a rubber composition containing a rubber component and silica, the rubber component containing an isoprene-based rubber and a styrene-butadiene rubber, the content of the isoprene-based rubber in the rubber component being 40% by mass or more, the content of the silica being 70 parts by mass or more relative to 100 parts by mass of the rubber component, the styrene content S1 (%) of the styrene-butadiene rubber being 30 or less, the acetone extraction amount AE (%) of the rubber composition being greater than 17.0, the half-peak width of the peak in the tanδ temperature distribution curve of the rubber composition in the range of -20°C to -70°C being 45°C or more, when the groove depth at the deepest part of the circumferential groove is set to H (mm), when the tanδ of the rubber composition at -10°C is set to -10°C tanδ, -10°C tanδ × H is 1.7 or more.

Effects of the Invention

[0007] According to the present invention, a tire can be provided that improves the comprehensive performance of snow performance and wet grip performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Figure 1

Figure 2

DESCRIPTION OF REFERENCE NUMERALS

[0218] 2: Ground contact portion 3: Tread surface 4: Straight line connecting the ends of the circumferential grooves 5: Extension line of the bottom of the circumferential groove 6: First layer 7: Second layer 8: Extension line of the outer side surface of the second layer t1: Thickness of the first layer t2: Thickness of the second layer T: Total thickness of the tread surface H: Groove depth of the deepest part of the circumferential groove P: Midpoint in the tire width direction N: Line perpendicular to the section plane at point P 10: Circumferential groove 11: Central circumferential groove 12: Outermost circumferential groove 20: Transverse groove 21: Transverse groove (sipe) 30: Shoulder ground contact portion 40: Central ground contact portion 41: Central ground contact portion CL: Tire center line Ti: Inner tread end To: Outer tread end TW: Tread width W: Tire width direction. DETAILED DESCRIPTION OF THE INVENTION

[0009] A tire according to an embodiment of the present invention has the following characteristics: It is a tire having a tread surface, the tread surface having one or more circumferential grooves, the tread surface being composed of a rubber composition containing a rubber component and silica, the rubber component containing an isoprene-based rubber and a styrene-butadiene rubber, the content of the isoprene-based rubber in the rubber component being 40% by mass or more, the content of the silica being 70 parts by mass or more relative to 100 parts by mass of the rubber component, the styrene content S1 (%) of the styrene-butadiene rubber being 30 or less, the acetone extraction amount AE (%) of the rubber composition being greater than 17.0, the half-peak width of the peak in the range of -20°C to -70°C of the tanδ temperature distribution curve of the rubber composition being 45°C or more, when the groove depth at the deepest part of the circumferential groove is set to H (mm) and the tanδ of the rubber composition at -10°C is set to -10°C tanδ, -10°C tanδ × H is 1.7 or more.

[0010] In the tire of this embodiment, regarding the reason for the improvement in the comprehensive performance of snow performance and wet grip performance, although it is not intended to be limited theoretically, the following speculation can be made.

[0011] The rubber composition constituting the tread surface of the tire of this embodiment, (1) by making the content of the isoprene-based rubber 40% by mass or more, an isoprene-based rubber phase with relatively weak interaction with silica is formed in the rubber matrix, and the followability of the rubber composition to the road surface is improved. In addition, (2) by making the content of silica 70 parts by mass or more relative to 100 parts by mass of the rubber component, the effect of improving the wet grip performance brought by silica can be obtained, and the tanδ temperature distribution curve can be made gentle. In addition, (3) by making the styrene content S1 (%) of the styrene-butadiene rubber 30 or less, minute styrene phase regions (domin) are formed in the rubber matrix. Since these minute phase regions have softness, the mobility of the polymer is improved, and the followability of the rubber composition to the road surface is improved. And since the glass transition temperature (Tg) of the rubber composition decreases, the snow performance is improved. In addition, (4) by making the acetone extraction amount AE (%) greater than 17.0, the efficiency of dispersion and distribution of the filler becomes better, so the rigidity at low temperature can be reduced. In addition, (5) by making the half-peak width of the peak in the range of -20°C to -70°C of the tanδ temperature distribution curve 45°C or more, energy loss can be generated in a wide frequency band, and energy loss in a wide range can be generated in the frequency band during braking on snow and a wet road surface. In addition, (6) by making -10°C tanδ × H 1.7 or more, the hysteresis loss and snow column shear force at low temperature are improved. It is also considered that: based on the synergistic effects of the above (1) to (6), a particularly remarkable effect of improving the comprehensive performance of snow performance and wet grip performance can be achieved.

[0012] The total styrene content S2 (mass %) in the above rubber component is preferably 15 or less.

[0013] It is considered that by making the total styrene content S2 15 mass % or less, minute styrene phase regions are formed in the rubber matrix. Since these minute phase regions have flexibility, the mobility of the polymer is improved, the followability of the rubber composition to the road surface is improved, and the comprehensive performance of snow performance and wet grip performance is further improved.

[0014] The above rubber composition preferably contains a resin component containing dicyclopentadiene, styrene, and indene as monomer components.

[0015] It is considered that by containing the above resin component, the compatibility with isoprene rubber or styrene-butadiene rubber is reduced, so that the tanδ temperature distribution curve can be made gentle, and the comprehensive performance of snow performance and wet grip performance is further improved.

[0016] The tanδ at -10°C of the above rubber composition is preferably 0.30 or more. It is considered that by making the tanδ at -10°C 0.30 or more, the snow performance is further improved.

[0017] The tanδ at -10°C × H of the above rubber composition is preferably 2.0 or more. It is considered that by making the tanδ at -10°C × H 2.0 or more, the hysteresis loss and snow column shear force at low temperature are further improved.

[0018] The acetone extraction amount of the above rubber composition is preferably more than 20.0 mass %. It is considered that by making the acetone extraction amount more than 20.0 mass %, since the efficiency of dispersion and distribution of the filler becomes better, the rigidity at low temperature can be further reduced.

[0019] The tanδ at 0°C of the above rubber composition is preferably 0.50 or more. It is considered that by making the tanδ at 0°C 0.50 or more, the snow performance is further improved.

[0020] When the total thickness of the above tread surface is set to T (mm), the tanδ at -10°C × T is preferably 1.5 or more and 3.5 or less. It is considered that by making the tanδ at -10°C × T 1.5 or more, the hysteresis loss at low temperature is improved, so that the snow performance is further improved, and by making it 3.5 or less, the fuel consumption performance can be ensured.

[0021] The above rubber composition preferably contains 20 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component. It is considered that by containing 20 parts by mass or more of carbon black, the reinforcing property of the rubber composition is improved, and thus the abrasion resistance performance is further improved.

[0022] When the ground contact area ratio of the above tread surface is set to R, S1×R is preferably 10.0 or more. It is considered that by setting S1×R to 10.0 or more, based on the synergistic effect of the softness of the rubber composition and the increase in the ground contact surface of the tread surface, the wet grip performance is further improved.

[0023] When the tire weight is set to G (kg), S1 / G is preferably 3.0 or less. It is considered that as the tire weight decreases, by reducing S1, the handling stability in a low-temperature environment becomes easier to improve. It is considered that the lighter the tire, the smaller the force when pressing the ground contact part against the road surface, and as the tire becomes lighter, even the aggregation of a small amount of styrene part has a greater impact on the tread surface.

[0024] Preferably, the number of the above circumferential grooves is 3 or more, and the tread surface has: a pair of shoulder ground contact parts divided by a pair of outermost circumferential grooves located at the outermost ends in the tire width direction, and 2 or more central ground contact parts located between the pair of shoulder ground contact parts. The groove width of at least one of the pair of outermost circumferential grooves is narrower than the groove width of at least one of the circumferential grooves other than the pair of outermost circumferential grooves. In addition, here, at least one of the outermost circumferential grooves whose groove width is narrower than at least one of the circumferential grooves other than the outermost circumferential grooves is preferably the outermost circumferential groove on the tread end To side of the pair of outermost circumferential grooves, and more preferably a pair of outermost circumferential grooves on both the tread end To side and the Ti side.

[0025] It is considered that by dividing the tread surface into 4 or more parts in the width direction, the load transmitted to each ground contact part becomes larger, the pressure pressing the rubber surface against the road surface can be increased, and the handling stability on a snow-covered road surface can be further improved. In addition, it is considered that when turning, the pressure on the outer side in the tire width direction of the tread surface of the tire inevitably tends to increase. By pre-narrowing the groove width as described above, the reaction force at the shoulder ground contact part can be increased, and the handling stability on a snow-covered road surface can be easily improved.

[0026] The above rubber composition preferably contains 30 parts by mass or more and 70 parts by mass or less of a softening agent with respect to 100 parts by mass of the rubber component. By containing 30 parts by mass or more and 70 parts by mass or less of the softening agent, the processability of the rubber composition is improved, and in addition, the appearance of the tire can be made good.

[0027] [Definition] "The styrene content S1 (mass%) of styrene-butadiene rubber" is the styrene content (mass%) of styrene-butadiene rubber (SBR). When the rubber component contains a single SBR, it is the styrene content of this SBR. When the rubber component contains multiple SBRs, it can be obtained by the sum of the products of the styrene content of each SBR and the compounding amount (mass%) of this SBR when the total SBR is set to 100 mass%.

[0028] For example, when the rubber component is composed of 20% by mass of a first SBR (styrene content: 25% by mass), 30% by mass of a second SBR (styrene content: 27.5% by mass), and 50% by mass of BR, the styrene content S1 of the styrene-butadiene rubber is 26.5% by mass (= (25×40 / 100) + (27.5×60 / 100)).

[0029] "Total styrene amount S2 (mass%) in the rubber component" is the total content (mass%) of the styrene portion contained in 100% by mass of the rubber component. For each rubber component, it is the value obtained by multiplying the styrene content (mass%) by the mass fraction in the rubber component and taking the sum of these values. Specifically, it can be calculated by Σ (styrene content (mass%) of each rubber containing styrene × content of each rubber containing styrene in the rubber component (%) / 100).

[0030] For example, when the rubber component is composed of 20% by mass of a first SBR (styrene content: 25% by mass), 30% by mass of a second SBR (styrene content: 27.5% by mass), and 50% by mass of BR, the total styrene amount S2 in 100% by mass of the rubber component is approximately 13.3% by mass (= (25×20 / 100) + (27.5×30 / 100) + (0×50 / 100)).

[0031] "Acetone extraction (AE) amount" is the value obtained by immersing each vulcanized rubber test piece in acetone at room temperature (around 25°C) for 72 hours according to JIS K 6229:2015, extracting the soluble components, measuring the mass of each test piece before and after extraction, and calculating using the following formula. Acetone extraction amount (mass%) = { (mass of the rubber test piece before extraction - mass of the rubber test piece after extraction) / (mass of the rubber test piece before extraction)} × 100

[0032] "The half-peak width of the peak in the tanδ temperature distribution curve of the rubber composition in the range of -20°C to -70°C (half-peak width of the tanδ peak)" can be obtained from the temperature distribution curve of tanδ measured by the method disclosed in Japanese Patent Application Laid-Open No. 2021-54377. That is, for each vulcanized test piece, using a dynamic viscoelasticity measuring device (for example, EPLEXOR series manufactured by GABO), under the conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / minute, the temperature distribution curve of tanδ is measured in the temperature range of -20°C to -70°C to obtain a temperature dispersion curve with the temperature on the X-axis and tanδ on the Y-axis. It is defined as follows: Let the tanδ at the peak position of the obtained temperature distribution curve be A, the intersection of the line passing through A and parallel to the Y-axis with the X-axis be B, the midpoint of the line segment AB be C, the line passing through C and parallel to the X-axis be D, and when the two intersections of D and the temperature distribution curve are E and F, the absolute value of the temperature difference between E and F.

[0033] "The tanδ at the peak position of the tanδ temperature distribution curve of the rubber composition in the range of -20°C to -70°C" can be obtained from the temperature distribution curve of tanδ measured by the method disclosed in Japanese Patent Application Laid-Open No. 2021-54377. That is, for each vulcanized test piece, using a dynamic viscoelasticity measuring device (for example, EPLEXOR series manufactured by GABO), under the conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / minute, the temperature distribution curve of tanδ is measured in the temperature range of -20°C to -70°C, and it is the tanδ at the peak position of the temperature dispersion curve with the temperature on the X-axis and tanδ on the Y-axis.

[0034] "The glass transition temperature (Tg) of the rubber composition" means: Using a dynamic viscoelasticity measuring device (for example, EPLEXOR series manufactured by GABO), under the conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2°C / minute, the temperature distribution curve of tanδ is measured, and it is the temperature (tanδ peak temperature) corresponding to the maximum value in the range of -60°C or higher and 40°C or lower in the obtained temperature distribution curve. In addition, in the measurement in the range of -60 to 40°C, when the tanδ value monotonically increases or decreases as the temperature rises, the glass transition temperature of the rubber composition is set to 40°C or -60°C, respectively. In addition, when there are two or more points indicating the maximum value in the range of -60°C or higher and 40°C or lower, the point with the lowest temperature is set as the glass transition temperature.

[0035] "-10°C tanδ" is the loss tangent (tanδ) measured under the conditions of a temperature of -10°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and a tensile mode.

[0036] "0 °C tanδ" is the tangent of the loss angle (tanδ) measured under the conditions of a temperature of 0 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and a tensile mode.

[0037] The "tread area" is the part that forms the ground contact surface of the tire. When the tire radial cross-section has components such as a belt layer or a belt reinforcing layer and a carcass layer that form the tire skeleton with steel or textile materials, it refers to the components located more outside the tire radially than these components.

[0038] The "normal state" means: a state of no load assembled on a normal rim and filled with air at normal internal pressure.

[0039] The "dimensions of each part of the tire": Unless otherwise specified, the "dimensions of each part of the tire" appearing on the outer side of the tire are values specified in the normal state. On the other hand, the "dimensions of each part of the tire" existing inside the tire are values specified in the state where the tire is cut by a plane including the tire rotation axis and the cut tire piece maintains the rim width of the normal rim.

[0040] The "normal rim" means: In the standard system including the standard on which the tire is based, the rim whose standard is specified for each tire. For example, it refers to the standard rim in the applicable dimensions recorded in the "JATMA YEAR BOOK" of JATMA (Japan Automobile Tire Association), the "Measuring Rim" recorded in the "STANDARDS MANUAL" of ETRTO (The European Tyre and Rim Technical Organisation), and the "Design Rim" recorded in the "YEAR BOOK" of TRA (The Tire and Rim Association, Inc.). Refer to them in the order of JATMA, ETRTO, and TRA. When there are applicable dimensions during reference, follow their standards. In addition, for tires not specified in the above standards, it refers to the rim with the smallest rim width among the rims with the smallest diameter that can be assembled and maintain internal pressure (that is, there is no air leakage between the rim and the tire).

[0041] "Normal internal pressure" means: in the standard system that includes the standard on which the tire is based, the air pressure specified for each tire by this standard. For example, it refers to the maximum value recorded in the "Maximum Air Pressure" of JATMA, the "INFLATION PRESSURE" of ETRTO, and the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" of TRA. Similar to the case of a normal rim, it is referenced in the order of JATMA, ETRTO, and TRA, and when there are applicable dimensions during the reference, the standards thereof shall be followed. In addition, for a tire not specified in the above standards, it refers to the normal internal pressure (where it is 250 kPa or more) of other tire sizes (where the tire is specified in the standard) with the above normal rim as the standard rim. When there are multiple normal internal pressures of 250 kPa or more recorded, it refers to the minimum value among them.

[0042] "Normal load" is the load specified for each tire by the standard in the standard system that includes the standard on which the tire is based. For example, it refers to the maximum value recorded in the "Maximum Load Capacity" of JATMA, the "LOAD CAPACITY" of ETRTO, and the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" of TRA. Similar to the cases of a normal rim and normal internal pressure, it is referenced in the order of JATMA, ETRTO, and TRA, and when there are applicable dimensions during the reference, the standards thereof shall be followed. At the same time, for a tire not specified in the above standards, the maximum load capacity W L calculated separately shall be set as the normal load.

[0043] "Maximum load capacity W L " is calculated by the following formula. "V" is the virtual volume of the tire (mm 3 ), "Dt" is the outer diameter of the tire in the normal state (mm), "Ht" is the sectional height of the tire in the tire diameter direction in the section of the tire based on the plane including the tire rotation axis (mm), and "Wt" is the sectional width of the tire in the normal state (mm). When the rim diameter of the tire is set as R, Ht can be obtained by (Dt - R) / 2. When there are patterns or characters on the tire sidewall, Wt is the value obtained after removing these. In addition, the maximum load capacity has the same meaning as the above normal load.

[0044]

Equation 1

[0045] "Groove" means a recess formed on the tread surface of a tire and extending radially inward of the tire, and refers to a recess having a groove width (opening width) of 2.0 mm or more at the tread surface. Similarly, a recess smaller than 2.0 mm is called a "sipe".

[0046] "Circumferential groove" means a groove extending continuously in the circumferential direction of the tire. The circumferential groove may extend linearly in the circumferential direction, or may extend in a wave shape, a sine shape, or a zigzag shape in the circumferential direction.

[0047] "Groove depth H (mm) at the deepest part of the circumferential groove" means, in a cross-section of the tire based on a plane including the tire rotation axis, the straight-line distance between the straight line connecting the ends of the groove in the tread surface and the straight line at the lowest part of the groove in the tire radial direction. When the groove depth of the groove varies in the tire width direction and / or the circumferential direction, the maximum value of the above straight-line distance is set as the groove depth of the groove (in addition, in the objects defined by the groove depth in this specification, the depth at locations such as intersections of multiple grooves with three or more branches is excluded).

[0048] "Total thickness T (mm) of the tread portion" is the thickness of the tread portion measured along the normal line at the tire equator in a cross-section of the tire based on a plane including the tire rotation axis. When there is a circumferential groove at the tire equator, it is the thickness measured along the normal line at the central part in the tire width direction of the grounding portion that is closer to the tire equator among the grounding portions on both lateral sides in the tire width direction of the groove. In addition, the total thickness T of the tread portion is the average value of the total thicknesses of the tread portion obtained by successively rotating the tire 72° in the circumferential direction and measuring at 5 positions.

[0049] "Weight G (kg) of the tire" means the weight excluding the rim, that is, the weight of the tire alone. On the other hand, when components such as those made of sponge and sealant or sensor components are provided in the inner cavity of the tire, it is set to include the weights of these.

[0050] "Contact area" is the area of the tread obtained from the contour when the tire is pressed against the ground. It can be obtained by assembling the tire on a regular rim, filling it with the regular internal pressure, leaving it to stand at 25°C for 24 hours, then coating the tread surface of the tire with ink, loading the tire with the regular load (maximum load capacity) and vertically pressing it on a cardboard (camber angle is 0°) to transfer the ink. The area of the contact area refers to the total contact area. The total contact area can be calculated by successively rotating the tire 72 degrees, performing the above transfer operation at a total of 5 positions, and taking the average value of the 5 obtained areas.

[0051] The "effective contact area region" is the region of the tread of the tire that comes into contact with the ground when the tire is pressed against the ground. It can be obtained by assembling the tire on a standard rim, filling it with the standard internal pressure, leaving it standing at 25°C for 24 hours, then applying ink to the surface of the tire tread, loading the tire with the standard load (maximum load capacity), and vertically pressing it onto cardboard (camber angle is 0°) to transfer the ink. The area of the effective contact area region refers to the effective contact area. The effective contact area can be calculated by rotating the tire by 72 degrees successively, performing the above transfer operation at a total of 5 locations, and taking the average of the 5 obtained areas.

[0052] The "contact area ratio R" is calculated by the following formula using the total contact area of the above contact area region and the effective contact area of the above effective contact area region. Contact area ratio = (Effective contact area / Total contact area)

[0053] The "contact part" refers to the part of the tread of the tire that comes into contact with the ground when the tire is pressed against the ground, and it is the part of the tread that constitutes the above effective contact area region.

[0054] The "tread ends Ti, To" refer to the outermost contact positions when the tire in the normal state is loaded with the maximum load capacity and contacts the ground on a plane with a camber angle of 0 degrees. The tread end Ti represents the tread end that becomes the inner side of the vehicle when installed on the vehicle, and the tread end To represents the tread end that becomes the outer side of the vehicle.

[0055] The "rubber component of the rubber composition" refers to the component that participates in crosslinking within the rubber composition, and is usually a component with a weight average molecular weight (Mw) of 10,000 or more.

[0056] The "glass transition temperature (Tg) of the rubber component" refers to the static glass transition temperature of each rubber component obtained by a differential scanning calorimeter (for example, Q200 manufactured by TA Instruments Japan Co., Ltd.).

[0057] The "styrene content" is a value calculated by 1 1H-NMR measurement, and is applicable to rubber components (rubbers containing styrene units) having repeating units derived from styrene such as SBR, for example.

[0058] The "vinyl content (1,2-bonded butadiene unit amount)" is a value calculated by infrared absorption spectroscopy in accordance with JIS K 6239-2:2017, and is applicable to rubber components having repeating units derived from butadiene such as SBR and BR, for example.

[0059] The "cis content (cis-1,4-bonded butadiene unit amount)" is a value calculated by infrared absorption spectroscopy in accordance with JIS K 6239-2:2017, and is applicable to rubber components having repeating units derived from butadiene such as BR, for example.

[0060] "Weight-average molecular weight (Mw)" is determined based on the measured values 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), and can be obtained by conversion with standard polystyrene. For example, it is applicable to SBR, BR, softeners, etc.

[0061] "Nitrogen adsorption specific surface area of carbon black (N2SA)" is measured according to JIS K 6217-2:2017. "Nitrogen adsorption specific surface area of silica (N2SA)" is measured by the BET method according to ASTM D3037-93.

[0062] "Average primary particle size" is obtained by taking pictures of the particles with a transmission or scanning electron microscope and calculating the arithmetic average of the particle sizes of 400 particles. For the particle size, when the shape of the particle is approximately circular, the diameter of the circle is defined as the particle size; when it is needle-shaped or rod-shaped, the short diameter is defined as the particle size; in other cases, the equivalent circle diameter calculated from the electron microscope image is defined as the particle size. The equivalent circle diameter can be obtained as the positive square root of "[4 × (area of the particle) / π]". The average primary particle size is applicable to silica, carbon black, etc.

[0063] "Content of softener" also includes the amount of softener contained in the rubber composition incremented in advance with softeners such as oil, resin components, and liquid rubber components. In addition, the same applies to the content of oil, resin components, and liquid rubber. For example, when the increment component is oil, the incremented oil is included in the content of oil.

[0064] "Softening point of resin component" is the temperature at which the ball drops when measuring the softening point specified in JIS K 6220-1:2015 7.7 with a ring and ball softening point measuring device.

[0065] [Tire] Hereinafter, a tire according to an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the embodiment shown below is only an example, and the tire of this embodiment is not limited to the following embodiment.

[0066] Figure 1 It is a cross-sectional view showing a cross-section passing through the tire rotation axis in the tread portion of the tire. Figure 1 In this figure, the up-down direction is the tire radial direction, the left-right direction is the tire width direction, and the direction perpendicular to the paper surface is the tire circumferential direction.

[0067] The tread portion of the tire according to the present invention has at least one or more circumferential grooves 1 (10). The tread portion has a ground contact portion 2 divided by the circumferential grooves 1 (10) in the tire width direction.

[0068] The groove depth H at the deepest part of the circumferential groove 1 (10) means the linear distance between the straight line 4 connecting the ends of the circumferential groove in the tread surface 3 and the extended line 5 of the lowest part of the groove in the tire radial direction. In addition, the groove depth H, for example, in the case of having a plurality of circumferential grooves 1 (10), may mean the linear distance between the straight line 4 and the extended line 5 of the lowest part of the circumferential groove 1 (10) ( Figure 1 in which, for the left circumferential groove 1) in the tire radial direction.

[0069] The tire of the present invention is preferably provided with a rubber layer composed of the rubber composition defined above on at least a part of the area at a distance H from the tread surface 3 in the tire radial direction inward. The tread part of the tire of the present invention has one or more rubber layers, preferably two or more rubber layers. In the case where the tread part has two or more rubber layers, at least one of the two or more rubber layers may be composed of the rubber composition defined above.

[0070] In the present invention, from the viewpoint of snow performance, the groove depth H at the deepest part in the circumferential direction is preferably 5.0 mm or more, more preferably 5.5 mm or more, further preferably 6.0 mm or more, and particularly preferably 6.5 mm or more. In addition, from the viewpoint of wet grip performance, the groove depth H at the deepest part of the circumferential groove is preferably 10.0 mm or less, more preferably 8.0 mm or less, further preferably 7.5 mm or less, and particularly preferably 7.0 mm or less.

[0071] The tread part, as Figure 1 shown, may also have: a first layer 6 whose outer surface constitutes the tread surface 3, and a second layer 7 adjacent to the radial inside of the first layer 6. Figure 1 The circumferential groove 1 (10) on the left side as shown is formed such that the deepest part of the groove bottom of the circumferential groove 1 (10) is located on the tire radial inside with respect to the outer surface of the second layer 7. Specifically, the second layer 7 has a recess recessed toward the tire radial inside with respect to the outer surface, and a part of the first layer 6 is formed in the recess of the second layer 7 with a specified thickness. The circumferential groove 1 (10) is formed in such a way as to pass through the outer surface of the second layer 7 and enter the inside of the recess of the second layer 7. In addition, the circumferential groove 1 (10) may also be formed with a groove depth that does not reach the outer surface of the second layer 7 as the circumferential groove 1 on the right side as Figure 1 shown.

[0072] Figure 1 In, the double arrow t1 is the thickness of the first layer 6, and the double arrow t2 is the thickness of the second layer 7. Figure 1 In, the midpoint in the tire width direction of the grounding part 2 is denoted by the symbol P. The straight line indicated by the symbol N is a straight line (normal line) passing through the point P and perpendicular to the tangent plane at the point P.

[0073] The thickness t1 of the first layer 6 is not particularly limited, preferably 3.5 mm or more, more preferably 4.2 mm or more, and still more preferably 4.5 mm or more. In addition, the thickness t1 of the first layer 6 is preferably 9.0 mm or less, more preferably 7.2 mm or less, and still more preferably 6.3 mm or less.

[0074] The thickness t2 of the second layer 7 is not particularly limited, preferably 0.5 mm or more, more preferably 0.6 mm or more, and still more preferably 0.7 mm or more. In addition, the thickness t2 of the second layer 7 is preferably 3.0 mm or less, more preferably 2.4 mm or less, and still more preferably 2.1 mm or less.

[0075] In the present invention, the total thickness T of the tread surface ( Figure 1 wherein t1 + t2) is preferably 4.0 mm or more, more preferably 5.0 mm or more, still more preferably 6.0 mm or more, particularly preferably 7.0 mm or more, and most preferably 8.0 mm or more. On the other hand, as the upper limit, there is no particular limitation, preferably 15.0 mm or less, more preferably 14.0 mm or less, and still more preferably 12.0 mm or less.

[0076] In the present invention, from the viewpoints of improving the efficiency of dispersion and distribution of fillers and reducing the rigidity at low temperatures, the acetone extract amount AE of the rubber composition constituting the tread surface is greater than 17.0% by mass, preferably greater than 20.0% by mass, more preferably greater than 22.0% by mass, still more preferably greater than 25.0% by mass, and particularly preferably greater than 27.0% by mass. In addition, from the viewpoint of handling stability performance, the acetone extract amount (AE) is preferably less than 35.0% by mass, more preferably less than 33.0% by mass, and still more preferably less than 30.0% by mass.

[0077] In the present invention, from the viewpoint of the effects of the present invention, the tanδ of the peak position in the range of -20°C to -70°C of the tanδ temperature distribution curve of the rubber composition constituting the tread surface is preferably -60°C or more, more preferably -50°C or more, and still more preferably -45°C or more.

[0078] In the present invention, the half-peak width of the above-mentioned peak is 45°C or more, preferably 46°C or more, more preferably 47°C or more, and still more preferably 48°C or more. By making the half-peak width of the peak 45°C or more, energy loss can be generated in a wide frequency band, and energy loss can be generated in a wide range even in the frequency band during braking on snow and wet roads. In addition, there may be multiple peaks in the tanδ temperature distribution curve. In this case, for at least one peak (curve), the half-peak width of the peak is within the above range.

[0079] In the present invention, from the perspective of snow performance, the -10°C tanδ of the rubber composition constituting the tread surface is preferably greater than 0.20, more preferably greater than 0.25, and further preferably greater than 0.27. In addition, from the perspective of low fuel consumption performance, the -10°C tanδ is preferably less than 0.50, more preferably less than 0.45, further preferably less than 0.40, and particularly preferably less than 0.35.

[0080] In the present invention, from the perspective of snow performance, the -10°C tanδ × H of the rubber composition constituting the tread surface is 1.7 or more, preferably 1.8 or more, and further preferably 2.0 or more. In addition, from the perspective of handling stability performance, the -10°C tanδ × H is preferably 3.0 or less, more preferably 2.8 or less, further preferably 2.6 or less, and particularly preferably 2.5 or less.

[0081] In the present invention, from the perspective of snow performance, the -10°C tanδ × T of the rubber composition constituting the tread surface is preferably 1.5 or more, more preferably 1.8 or more, further preferably 2.0 or more, particularly preferably 2.2 or more, and most preferably 2.5 or more. In addition, from the perspective of low fuel consumption performance, the -10°C tanδ × T is preferably 4.0 or less, more preferably 3.8 or less, further preferably 3.5 or less, and particularly preferably 3.1 or less.

[0082] In the present invention, from the perspective of snow performance, the 0°C tanδ of the rubber composition constituting the tread surface is preferably greater than 0.40, more preferably greater than 0.45, further preferably greater than 0.50, and further preferably greater than 0.55. In addition, from the perspective of low fuel consumption performance, the 0°C tanδ is preferably less than 0.70, more preferably less than 0.65, and further preferably less than 0.60.

[0083] In the present invention, from the perspective of the effects of the present invention, the glass transition temperature (Tg) of the rubber composition constituting the tread surface is preferably greater than -65°C, more preferably greater than -60°C, further preferably greater than -55°C, further preferably greater than -50°C, and particularly preferably greater than -45°C. In addition, from the perspective of snow performance, it is preferably less than -20°C, more preferably less than -25°C, and further preferably less than -30°C.

[0084] 《Tread Pattern》 Figure 2 It is a developed view of the tread surface showing an embodiment of the present invention. W represents the tire width direction. TW represents the distance between the inner tread end Ti and the outer tread end To in the tire width direction W. Figure 2In this case, the tread surface has five circumferential grooves 10. The central circumferential groove 11 with the widest width extends above the tire center line CL, a pair of central circumferential grooves 11 with slightly narrower widths extend outside it, and further, a pair of outermost circumferential grooves 12 with narrow widths extend outside them. In the shoulder contact portion 30 of the tire, one end of the transverse groove 20 reaches the tread contact end Ti or To, and the other end reaches the outermost circumferential groove. In a pair of central contact portions 40 adjacent to the central circumferential groove 11 extending on the tire center line CL, both ends of the transverse groove (slit) 21 communicate with the two central circumferential grooves 11 that divide the central contact portion respectively. No transverse groove is formed in a pair of central contact portions 41 located further outside the central contact portion.

[0085] In the tire of the present invention, the tread surface has one or more circumferential grooves, preferably two or more circumferential grooves, more preferably three or more circumferential grooves, still more preferably four or more circumferential grooves, and particularly preferably five or more circumferential grooves.

[0086] When the number of circumferential grooves is three, the tread surface has a pair of outermost circumferential grooves and a central circumferential groove, and has four contact portions composed of a pair of shoulder contact portions and a pair of central contact portions. When the circumferential grooves are four, the tread surface has a pair of outermost circumferential grooves and a pair of central circumferential grooves. When the circumferential grooves are five, the tread surface has a pair of outermost circumferential grooves and three central circumferential grooves.

[0087] Preferably, in the tread surface of the tire according to this embodiment, the number of circumferential grooves 10 is three or more, and it has: a pair of shoulder contact portions 30 divided by a pair of outermost circumferential grooves 12 located at the outermost ends in the tire width direction, and two or more central contact portions 40 between the pair of shoulder contact portions 30. The groove width of at least one of the pair of outermost circumferential grooves 12 is preferably smaller than the groove width of at least one of the circumferential grooves 11 other than the pair of outermost circumferential grooves. In addition, it is preferable that the groove widths of the pair of outermost circumferential grooves are both smaller than the groove width of the central circumferential groove.

[0088] The tread surface of the tire according to this embodiment preferably has a plurality of transverse grooves 20 extending in the tire width direction. The width of the transverse groove is not particularly limited, and is usually 8 mm or less. The direction of the transverse groove may also have a specified angle (θ) with respect to the tire width direction W. The range of θ is, for example, 0° to ±80°. In one transverse groove, θ can be a fixed value at any position in the tire width direction, or θ can change as the position in the tire width direction changes.

[0089] From the viewpoint of the effects of the present invention, the ground contact area ratio R of the tire according to the present embodiment is preferably 0.80 or less, more preferably 0.75 or less, and still more preferably 0.70 or less. In addition, from the viewpoint of wear resistance, the ground contact area ratio R is preferably 0.50 or more, more preferably 0.55 or more, and still more preferably 0.60 or more.

[0090] The weight G of the tire according to the present embodiment is preferably 7.0 kg or more, more preferably 8.0 kg or more, and still more preferably 9.0 kg or more. The upper limit value of the tire weight G is not particularly limited and is usually 100 kg or less. For example, it can be 80 kg or less, 60 kg or less, 40 kg or less, etc.

[0091] In addition, various physical properties such as -10°C tanδ and 0°C tanδ of the rubber composition can be appropriately adjusted according to the types and compounding amounts of the following rubber components, fillers, softeners, etc. For example, -10°C tanδ can be adjusted according to the types of rubber components and resin components.

[0092] [Rubber Composition] The rubber composition constituting the tread portion of the tire according to the present embodiment (hereinafter referred to as the rubber composition according to the present embodiment) will be described.

[0093] The rubber composition according to the present embodiment contains a rubber component containing an isoprene rubber and a styrene-butadiene rubber and silica. The rubber component according to the present embodiment is preferably a rubber component containing an isoprene rubber, a styrene-butadiene rubber, and a butadiene rubber.

[0094] [Rubber Component] [Isoprene Rubber] As the isoprene rubber, for example, substances commonly used in the tire industry such as isoprene rubber (IR) and natural rubber can be used. Among natural rubbers, in addition to unmodified natural rubber (NR), modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, and grafted natural rubber are also included. These isoprene rubbers can be used alone or in combination of two or more.

[0095] As NR, there is no particular limitation, and substances commonly used in the tire industry can be used. For example, SIR20, RSS#3, TSR20, etc. can be cited.

[0096] From the viewpoint of the effects of the present invention, the content of the isoprene rubber in the rubber component is 40% by mass or more, preferably more than 40% by mass, and more preferably 45% by mass or more. Further, the content of the isoprene rubber is preferably less than 80% by mass, more preferably less than 70% by mass, more preferably less than 60% by mass, and still more preferably 50% by mass or less.

[0097] (SBR) There is no particular limitation on the SBR, and examples thereof include solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs (modified S-SBR, modified E-SBR) thereof. As the modified SBR, examples include SBR modified at the terminal and / or main chain with a compound (modifying agent) having the following functional groups; modified SBR coupled with tin, silicon compounds, etc. (condensates, substances having a branched structure, etc.). Further, hydrides of these SBRs (hydrogenated SBR) can also be used. These SBRs can be used alone or in combination of two or more.

[0098] As the functional groups of the above-mentioned modifying agent, functional groups containing at least one element selected from silicon, nitrogen, and oxygen are preferred. As such functional groups, for example, amino group, amide group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, ureido group, ether group, carbonyl group, oxycarbonyl group, mercapto group, thioether group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazine bridge group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group (preferably alkoxy group having 1 to 6 carbon atoms), hydroxyl group, oxy group, epoxy group, etc. are exemplified, and amino group and / or alkoxysilyl group are preferred. As the amino group, an amino group substituted with 1 to 2 alkyl groups having 1 to 6 carbon atoms is preferred. As specific examples of the alkoxysilane, for example, trimethoxysilane, triethoxysilane, triisopropoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethylmethoxysilyl, dimethylethoxysilyl, etc. are exemplified.

[0099] As the SBR, oil-extended SBR or non-oil-extended SBR can be used. As the SBR that can be used in the present embodiment, commercially available substances from JSR Corporation, Sumitomo Chemical Co., Ltd., UBE Industries, Ltd., Asahi Kasei Corporation, ZSELASTOMERS Co., Ltd., ARLANXEO Corporation, etc. can be used.

[0100] From the perspective of the effects of the present invention, the styrene content S1 of SBR is 30% by mass or less, preferably 28% by mass or less, more preferably 25% by mass or less, further preferably 23% by mass or less, further preferably 20% by mass or less, further preferably 18% by mass or less, and particularly preferably 15% by mass or less. In addition, from the perspective of ensuring hysteresis loss, S1 is preferably 5% by mass or more, more preferably 8% by mass or more, and further preferably 10% by mass or more.

[0101] From the perspective of ensuring hysteresis loss, the vinyl content of SBR is preferably greater than 15 mol%, more preferably greater than 18 mol%, and further preferably greater than 20 mol%. In addition, from the perspective of low fuel consumption performance, the vinyl content of SBR is preferably less than 50 mol%, more preferably less than 45 mol%, and further preferably less than 30 mol%. In addition, in this specification, the vinyl content of SBR is measured by the above-mentioned measurement method.

[0102] From the perspective of the effects of the present invention, S1×R is preferably 5.5 or more, more preferably 6.5 or more, further preferably 10.0 or more, and particularly preferably 12.0 or more. In addition, S1×R is preferably 20.0 or less, more preferably 18.0 or less, and further preferably 17.0 or less.

[0103] From the perspective of the effects of the present invention, S1 / G is preferably 1.60 or more, more preferably 1.80 or more, and further preferably 2.10 or more. In addition, S1 / G is preferably 3.00 or less, more preferably 2.80 or less, and further preferably 2.70 or less.

[0104] From the perspective of the effects of the present invention, the glass transition temperature (Tg) of SBR is preferably -30°C or lower, more preferably -40°C or lower, further preferably -50°C or lower, further preferably -55°C or lower, and particularly preferably -60°C or lower. In addition, from the perspective of abrasion resistance performance, it is preferably -90°C or higher, more preferably -80°C or higher, and further preferably -70°C or higher.

[0105] From the perspective of the effects of the present invention, the weight average molecular weight (Mw) of SBR is preferably greater than 80,000, more preferably greater than 100,000, further preferably greater than 150,000, and particularly preferably greater than 500,000. In addition, from the perspectives of crosslinking uniformity, etc., Mw is preferably less than 2,000,000, more preferably less than 1,500,000, and further preferably less than 1,100,000. In addition, the Mw of SBR is measured by the above-mentioned measurement method.

[0106] From the viewpoint of the effects of the present invention, the content in the rubber component of SBR is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass or more. In addition, the content in the rubber component of SBR is preferably 60% by mass or less, more preferably less than 60% by mass, and still more preferably 50% by mass or less.

[0107] (BR) There is no particular limitation on BR. For example, BR with a cis content of less than 50 mol% (low-cis BR), BR with a cis content of 90 mol% or more (high-cis BR), rare-earth series butadiene rubber synthesized with a rare-earth element series catalyst (rare-earth series BR), BR containing syndiotactic polybutadiene crystals (BR containing SPB), modified BR (high-cis modified BR, low-cis modified BR), etc., which are commonly used in the tire industry, can be used. These BRs can be used alone or in combination of two or more.

[0108] As the high-cis BR, for example, commercially available products from Zeon Corporation, UBE Industries, Ltd., JSR Corporation, etc. can be used. By containing high-cis BR, the low-temperature properties and abrasion resistance can be improved. The cis content of the high-cis BR is preferably more than 95 mol%, more preferably more than 96 mol%, and still more preferably more than 97 mol%. In addition, the cis content of BR is measured by the above-mentioned measurement method.

[0109] As the rare-earth series BR, it is synthesized with a rare-earth element series catalyst, the vinyl content is preferably less than 1.8 mol%, more preferably less than 1.6 mol%, and still more preferably 1.5 mol% or less, and the cis content is preferably more than 95 mol%, more preferably more than 96 mol%, and still more preferably 97 mol% or more. As the rare-earth series BR, for example, commercially available products from Lanxess Corporation, etc. can be used.

[0110] Examples of BR containing SPB include substances in which 1,2-syndiotactic polybutadiene crystals are not simply dispersed in BR but are chemically bonded to BR and dispersed as crystals. As such BR containing SPB, commercially available products from UBE Industries, Ltd., etc. can be used.

[0111] As the modified BR, in addition to BR modified with the same functional groups as those described in the above SBR, etc., modified butadiene rubber (modified BR) in which the terminal and / or main chain is modified with a functional group containing at least one element selected from silicon, nitrogen, and oxygen can also be preferably used.

[0112] As other modified BRs, those obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound can be mentioned. Further, modified BRs in which the terminals of the modified BR molecules are bonded by tin-carbon bonds (tin-modified BRs) and the like can be mentioned. In addition, the modified BR can be an unhydrogenated modified BR or any one of hydrogenated modified BRs.

[0113] From the viewpoint of abrasion resistance, the weight-average molecular weight (Mw) of BR is preferably greater than 300,000, more preferably greater than 350,000, and further preferably greater than 400,000. In addition, from the viewpoints of crosslinking uniformity and the like, it is preferably less than 2,000,000, more preferably less than 1,000,000, and further preferably less than 500,000. In addition, Mw can be determined by the above method.

[0114] From the viewpoint of the effects of the present invention, the content of BR in the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more. In addition, the content of BR in the rubber component is preferably less than 50% by mass, more preferably less than 40% by mass, and further preferably less than 30% by mass.

[0115] From the viewpoint of the effects of the present invention, the total styrene amount S2 in the rubber component is preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 8% by mass or less. In addition, S2 is preferably 3% by mass or more, more preferably 5% by mass or more, and further preferably 7% by mass or more.

[0116] (Other rubber components) Within a range that does not affect the effects of the present invention, the rubber component may further contain rubber components other than isoprene rubber, SBR, and BR. As other rubber components, rubber components commonly used in the tire industry can be used. For example, ethylene-propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), chlorinated ether rubber, etc. can be mentioned. These other rubber components can be used alone or in combination of two or more. In addition, a known thermoplastic elastomer may or may not be contained in addition to the above rubber components.

[0117] (Rubber components synthesized from recycled / biomass-derived raw materials) The monomers that are the constituent units of synthetic rubbers such as IR, SBR, and BR can be substances derived from underground resources such as petroleum and natural gas, or substances recovered from rubber products such as tires or non-rubber products such as polystyrene. As the monomers obtained by recovery (recovered monomers), there is no particular limitation, and examples include recovered polyisoprene, recovered butadiene, recovered aromatic vinyl compounds, etc. As the above butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the above aromatic vinyl compound, there is no particular limitation, and styrene etc. can be mentioned. Among them, it is preferable to use recovered polyisoprene (recovered isoprene), recovered butadiene, and recovered styrene as raw materials.

[0118] As the method for producing the recovered monomer, there is no particular limitation. For example, it can be mentioned that it is synthesized from recovered naphtha obtained by pyrolyzing rubber products such as tires. In addition, as the method for producing the recovered naphtha, there is no particular limitation. For example, rubber products such as tires can be pyrolyzed under high temperature and high pressure, pyrolyzed with microwaves, or extracted after mechanical pulverization.

[0119] Furthermore, the monomers that are the constituent units of polymers such as IR, SBR, and BR can also be substances derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. As the biomass, there is no particular limitation, and examples include substances derived from agricultural, forestry, and fishery products or sugars, wood chips, plant residues after obtaining useful components, ethanol of plants, biomass naphtha, etc.

[0120] As the monomers derived from biomass (biomass monomers), there is no particular limitation, and examples include butadiene derived from biomass, aromatic vinyl compounds derived from biomass, etc. As the above butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the above aromatic vinyl compound, there is no particular limitation, and styrene etc. can be mentioned. In addition, the method for producing the monomers derived from biomass is not particularly limited. For example, substances obtained by biological and / or chemical and / or physical conversion of animals and plants can be mentioned. As the biological conversion, fermentation based on microorganisms is representative. As the chemical and / or physical conversion, conversion based on a catalyst, conversion based on high heat, conversion based on high pressure, conversion based on electromagnetic waves, conversion based on supercritical fluids, and combinations thereof can be mentioned.

[0121] As the polymer synthesized from biomass monomer components (biomass polymer), there is no particular limitation, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compound, etc. As the above-mentioned aromatic vinyl / butadiene copolymer, for example, styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene can be mentioned.

[0122] Whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D6866-10. pMC means: the 14 C concentration of the sample relative to that of the 14 modern standard reference of C is the ratio, and it is a value used as an index indicating the biomass ratio of the compound. The meaning of this value will be described below.

[0123] In 1 mole (6.02×10 23 pieces) of carbon atoms, there is about one trillionth of the normal carbon atoms, that is, about 6.02×10 11 pieces 14 of 14 14 C. The half-life of 14 14 C is 5730 years, and 14 14 C decreases regularly. Therefore, it is considered that after carbon dioxide in the atmosphere and the like are absorbed and immobilized by plants and the like, in fossil fuels such as coal, oil, and natural gas that have experienced more than 226,000 years, all of the 14 14 C elements contained therein at the time of initial immobilization have decayed. Therefore, in the 21st century today, fossil fuels such as coal, oil, and natural gas do not contain 14 14 C elements at all. Therefore, chemical substances produced using these fossil fuels as raw materials also do not contain

[0124] On the other hand, 14 14 C is continuously generated by nuclear reactions in the atmosphere by cosmic rays. Therefore, 14 the decrease of 14 14 C due to radioactive decay and the generation of 14 14 C due to nuclear reactions reach an equilibrium, and in the atmospheric environment of the earth, -12 the amount of

[0125] 14 C is a constant amount. Therefore, in the current environment, the14 C is measured as described below. Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 C) is measured. When measuring, as the standard modern carbon for the benchmark of the 14 C concentration, the 14 C concentration in the circulating carbon in nature in 1950 is adopted. As a specific standard substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (the radioactivity intensity of 14 C per 1 g of carbon) is classified according to each carbon isotope, 13 C is corrected to a fixed value, and the value after applying the decay correction from 1950 AD to the measurement date is used as the standard 14 C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0126] Therefore, if the rubber is 100% made of biomass-derived materials, although there are regional differences, etc., since it is mostly not 100 under normal conditions now, it is expected to show a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, a value of about 0 pMC (for example, 0.3 pMC) is shown. This value corresponds to a biomass ratio of 0%.

[0127] In summary, it is preferable in terms of environmental protection to use materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in the rubber composition.

[0128] [Filler] The rubber composition according to this embodiment contains silica as a filler. It is more preferably to contain silica and carbon black. In addition, the filler can also be a filler composed only of carbon black and silica.

[0129] [Silica] As silicon dioxide, there is no particular limitation, for example, silicon dioxide (anhydrous silicon dioxide) prepared by a dry method, silicon dioxide (hydrous silicon dioxide) prepared by a wet method, and other silicon dioxide commonly used in the tire industry can be used. As the raw material of silicon dioxide, there is no particular limitation, for example, it can be a raw material derived from minerals such as quartz, it can also be a raw material derived from organisms such as rice husks (for example, silicon dioxide using biomass materials such as rice husks as raw materials, etc.), and silicon dioxide recovered from products containing silicon dioxide can also be used. Among them, due to the large number of silanol groups, hydrous silicon dioxide prepared by a wet method is preferred. These silicon dioxides can be used alone or in combination of two or more.

[0130] Silicon dioxide made from biomass materials can be obtained by, for example, pre-silicated with sodium hydroxide solution from rice husk ash obtained by burning rice husks, filtering the silicate in the same manner as conventional wet silica to form a silicon dioxide precipitate by reaction with sulfuric acid, washing with water, drying, and pulverizing. Amorphous silicon dioxide extracted from rice husks can be commercially available materials such as Wilmar.

[0131] Silica recovered from products containing silica, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, diatomaceous earth and other filter materials can be used. In addition, the recovery method is not particularly limited, and thermal cracking, electromagnetic wave cracking, etc. can be cited. Among them, silica recovered from electronic components such as semiconductors or tires is preferred.

[0132] If silicon dioxide is crystallized, it is insoluble in water, and silicic acid as a component cannot be used. By managing the combustion temperature and combustion time, the crystallization of silicon dioxide in rice husk ash can be suppressed (refer to Japanese Patent Publication No. 2009-2594, Akita Prefectural University Online Journal B (Akita Prefectural University ウェブジャーナルB) / 2019, vol.6, p.216-222, etc.). Amorphous silicon dioxide extracted from rice husks can use commercially available substances such as Wilmar.

[0133] From the viewpoint of reinforcement, the nitrogen adsorption specific surface area (N2SA) of silica is preferably greater than 110 m 2 / g, more preferably greater than 130m 2 / g, more preferably greater than 150m 2 / g, particularly preferably greater than 170m 2 / g. In addition, from the viewpoint of heat generation and processability, it is preferably less than 220m 2 / g, more preferably less than 200m 2 / g, more preferably less than 180m 2 / g. In addition, the N2SA of silica is measured by the above-mentioned measurement method.

[0134] From the viewpoint of the effects of the present invention, the average primary particle diameter of the silica is preferably greater than 10 nm, more preferably greater than 12 nm, and further preferably greater than 14 nm. In addition, the average primary particle diameter is preferably less than 20 nm, more preferably less than 18 nm, and further preferably less than 17 nm. In addition, the average primary particle diameter of the silica is measured by the above-mentioned measuring method.

[0135] From the viewpoint of the effects of the present invention, the content of the silica relative to 100 parts by mass of the rubber component is preferably greater than 60 parts by mass, more preferably greater than 70 parts by mass, further preferably 80 parts by mass or more, and particularly preferably greater than 90 parts by mass. In addition, from the viewpoint of compatibility with the isoprene rubber, the content of the silica relative to 100 parts by mass of the rubber component is preferably less than 200 parts by mass, more preferably 110 parts by mass or less, and further preferably 100 parts by mass or less.

[0136] From the viewpoint of the effects of the present invention, the content of the silica in the filler is preferably greater than 60% by mass, more preferably greater than 70% by mass, further preferably greater than 72% by mass, and particularly preferably greater than 75% by mass. In addition, from the viewpoint of abrasion resistance performance, it is preferably less than 95% by mass, more preferably less than 92% by mass, and further preferably less than 90% by mass.

[0137] <Carbon black> As the carbon black, there is no particular limitation, and examples thereof include GPF, FEF, HAF, ISAF, SAF, etc. Substances commonly used in the tire industry can be used. Specifically, N110, N115, N120, N125, N134, N135, N219, N220, N231, N234, N293, N299, N326, N330, N339, N343, N347, N351, N356, N358, N375, N539, N550, N582, N630, N642, N650, N660, N683, N754, N762, N765, N772, N774, N787, N907, N908, N990, N991, etc. can be preferably used. Synthetic products of this company other than these can be preferably used. The raw material of the carbon black can be biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by pyrolyzing waste tires. In addition, the manufacturing method of the carbon black can be a combustion-based method such as the furnace method, a method based on hydrothermal carbonization (HTC), or a method based on the pyrolysis of methane derived from the thermal cracking carbon black method, etc. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbia Carbon Company, etc. can be used. These can be used alone or in combination of two or more.

[0138] In addition, as the carbon black, in addition to the above, from the perspective of life cycle assessment, etc., recycled carbon black obtained by pyrolyzing and refining carbon black using biomass materials such as lignin as raw materials and products containing carbon black such as tires can also be used.

[0139] In this specification, "recycled carbon black" refers to carbon black obtained by pulverizing products such as used tires containing carbon black and firing the pulverized matter. When measured by thermogravimetry based on JIS K 6226-2:2003 and oxidized and burned by heating in air, the proportion of the non-combustible component, that is, the mass (ash content) of ash, is 13% by mass or more. That is, the proportion of the mass (carbon content) of the reduced amount based on the above oxidation combustion of the recycled carbon black is 87% by mass or less. Recycled carbon black is sometimes represented by rCB.

[0140] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975 describes that "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408 - 449 (2012), especially pages 438, 440, and 442 mention that pyrolysis of organic materials is carried out at 550 - 800 °C after removing oxygen, or vacuum pyrolysis at relatively low temperatures (

[0027] ). The carbon black obtained by such a pyrolysis process is usually recycled carbon black lacking functional groups on its surface (comparison of the surface morphology and chemistry of pyrolysis carbon black and commercially available carbon black, Powder Technology 160 (2005) 190 - 193), as mentioned in

[0004] of Patent No. 6856781).

[0141] Recycled carbon black can be carbon black lacking functional groups on its surface, or it can also be carbon black that has been treated to make its surface contain functional groups. The treatment to make the surface of recycled carbon black contain functional groups can be carried out by conventional methods. For example, in European Patent Application Publication No. 3173251, carbon black obtained from a pyrolysis process is treated with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl groups and / or carboxyl groups on its surface. In addition, in Patent No. 6856781, carbon black obtained from a pyrolysis process is treated with an amino acid compound containing at least one mercapto group or disulfide group to obtain carbon black with an activated surface. The recycled carbon black involved in this embodiment includes such carbon black treated to make its surface contain functional groups.

[0142] Commercially available substances such as those from Strable Green Carbon Company and LDCarbon Company can be used as recycled carbon black.

[0143] From the perspective of reinforcing properties, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably greater than 160 m 2 / g, more preferably greater than 165 m 2 / g, further preferably greater than 170 m 2 / g, and particularly preferably greater than 175 m 2 / g. In addition, from the perspectives of heat generation and processability, it is preferably less than 200 m 2 / g. More preferably, it is less than 195 m 2 / g, and further preferably less than 190 m 2 / g. In addition, the N2SA of carbon black is measured by the above-mentioned measurement method.

[0144] The average primary particle diameter of the carbon black is preferably less than 100 nm, more preferably less than 50 nm, further preferably less than 30 nm, further preferably less than 26 nm, further preferably less than 21 nm, and most preferably less than 18 nm. In addition, the average primary particle diameter is preferably greater than 8 nm, more preferably greater than 10 nm, further preferably greater than 12 nm, further preferably greater than 14 nm, and particularly preferably greater than 15 nm. In addition, the average primary particle diameter of the carbon black is measured by the above-mentioned measuring method.

[0145] From the viewpoint of abrasion resistance performance, the content of the carbon black relative to 100 parts by mass of the rubber component is preferably greater than 10 parts by mass, more preferably 15 parts by mass or more, further preferably 20 parts by mass or more, and particularly preferably greater than 25 parts by mass. In addition, the content is preferably less than 50 parts by mass, more preferably less than 40 parts by mass, and further preferably 30 parts by mass or less.

[0146] <Other fillers> The filler may further contain other fillers other than silica and carbon black. There is no particular limitation on the other fillers. For example, substances commonly used in the tire industry in the past, such as aluminum hydroxide, calcium carbonate, alumina, clay, and talc, can be compounded.

[0147] The total content of the filler relative to 100 parts by mass of the rubber component is preferably greater than 80 parts by mass, more preferably greater than 90 parts by mass, further preferably greater than 100 parts by mass, and particularly preferably greater than 110 parts by mass. In addition, the total content is preferably less than 200 parts by mass, more preferably less than 180 parts by mass, further preferably less than 160 parts by mass, and particularly preferably less than 150 parts by mass.

[0148] <Silane coupling agent> Silica is preferably used in combination with a silane coupling agent. There is no particular limitation on the silane coupling agent. For example, sulfur-containing silane coupling agents such as bis(3-triethoxysilylpropyl) disulfide and bis(3-triethoxysilylpropyl) tetrasulfide can be cited; mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane; vinyl-based silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidyloxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc. Among them, sulfur-containing silane coupling agents and / or mercapto-based silane coupling agents are preferred. As the silane coupling agent, for example, commercially available substances from Evonik Degussa, Momentive, etc. can be used. These silane coupling agents can be used alone or in combination of two or more.

[0149] From the viewpoint of improving the dispersibility of silica, the content of the silane coupling agent relative to 100 parts by mass of the rubber component (when multiple silane coupling agents are used in combination, it is the total amount of all) is preferably greater than 3.0 parts by mass, more preferably greater than 5.0 parts by mass, and further preferably 6.0 parts by mass or more. In addition, from the viewpoint of preventing the reduction of wear resistance, it is preferably less than 15 parts by mass, more preferably less than 10 parts by mass, and further preferably less than 8.0 parts by mass.

[0150] [Other compounding agents] In the rubber composition according to this embodiment, in addition to the rubber component and the filler, compounding agents commonly used in the tire industry in the past can be appropriately contained, such as softeners, processing aids, waxes, stearic acid, zinc oxide, anti-aging agents, vulcanizing agents, vulcanization accelerators, etc.

[0151] [Softener] A softener refers to a material that imparts plasticity to the rubber component, and is a concept including softeners that are liquid at 25°C and softeners that are solid at room temperature (25°C). As examples of softeners, resin components, oils, liquid rubbers, ester-based plasticizers, etc. can be cited. These softeners can be substances derived from mineral resources such as petroleum and natural gas, or substances derived from biomass. In addition, low-molecular-weight hydrocarbon components obtained by thermal cracking and extraction of used tires and products containing various components can also be used as softeners. These softeners can be used alone or in combination of two or more.

[0152] (Resin component) The resin component is not particularly limited, and resin components commonly used in the tire industry can be used. For example, adhesive resins such as dicyclopentadiene-based resins, aromatic vinyl-based resins, coumarone-based resins, indene-based resins, C9-based resins, C5-based resins, C5C9-based resins, terpene-based resins, rosin-based resins, and phenolic-based resins can be cited. These resin components can be used alone or in combination of two or more. The rubber composition according to the present embodiment preferably contains a resin component containing dicyclopentadiene, styrene, and indene as monomer components.

[0153] 《Dicyclopentadiene-based resin》 "Dicyclopentadiene-based resin" refers to a resin containing cyclopentadiene (CPD) or dicyclopentadiene (DCPD), and may also be their hydrogenated products or modified products. As dicyclopentadiene-based resins, for example, DCPD / C9 resins containing dicyclopentadiene and the following C9 fraction as monomer components can be cited. As DCPD resins, DCPD / C9 resins with dicyclopentadiene and styrene as monomer components are preferred, and DCPD / C9 resins containing dicyclopentadiene, styrene, and indene as monomer components are particularly preferred. As DCPD resins, for example, commercially available substances from ExxonMobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. can be used.

[0154] 《Aromatic vinyl-based resin>> "Aromatic vinyl-based resin" refers to a resin containing aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene as the monomer component with the largest content, and may also be their hydrogenated products or modified products. As aromatic vinyl-based resins, due to economic efficiency, easy processing, and excellent heat generation properties, homopolymers of α-methylstyrene or styrene or copolymers of α-methylstyrene and styrene are preferred, and copolymers of α-methylstyrene and styrene are more preferred. As aromatic vinyl-based resins, for example, commercially available substances from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used.

[0155] 《Coumarone-based resin》 "Coumarone-based resin" refers to a resin containing coumarone as a monomer component, and may also be its hydrogenated product or modified product. As coumarone resins, for example, coumarone / indene resins containing coumarone and indene as monomer components, coumarone / indene / styrene resins containing coumarone, indene, and styrene as monomer components, etc. can be cited.

[0156] <<Indene-based resin》 "Indene-based resin" refers to: resins containing indene as a monomer component, which may also be their hydrogenated products or modified products. As indene-based resins, for example, coumarone / indene resins containing coumarone and indene as monomer components, coumarone / indene / styrene resins containing coumarone, indene, and styrene as monomer components, etc. can be cited.

[0157] "C9-based resin" "C9-based resin" refers to resins obtained by polymerizing C9 fractions, which may be resins obtained by polymerizing C9 fractions alone or copolymers obtained by copolymerizing C9 fractions with other components. For example, resins obtained by copolymerizing dicyclopentadiene (DCPD) with C9 fractions are called DCPD / C9 resins. In addition, they may also be their hydrogenated products or modified products. As C9 fractions, for example, petroleum fractions equivalent to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, dicyclopentadiene, etc. can be cited.

[0158] "C5-based resin" "C5-based resin" refers to: resins obtained by polymerizing C5 fractions, which may also be their hydrogenated products or modified products. As C5 fractions, for example, petroleum fractions equivalent to 4 to 5 carbon atoms such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, pentadiene, etc. can be cited.

[0159] "C5C9-based resin" "C5C9-based resin" refers to: resins obtained by copolymerizing the above C5 fractions with the above C9 fractions, which may also be their hydrogenated products or modified products. As C5C9-based petroleum resins, for example, commercially available substances from Tosoh Corporation, LUHUA Corporation, etc.

[0160] "Terpene-based resin" "Terpene-based resin" refers to: resins with terpene compounds such as α-pinene, β-pinene, limonene, dipentene, etc. as the monomer component with the highest content, which may also be their hydrogenated products or modified products. As specific examples of terpene-based resins, for example, polyterpene resins containing only one or more of the above terpene compounds as monomer components can be cited; aromatic modified terpene resins containing the above terpene compounds and aromatic compounds as monomer components; terpene phenolic resins containing the above terpene compounds and phenolic compounds as monomer components, etc. As monomer components of aromatic modified terpene resins, i.e., aromatic compounds, for example, styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. can be cited. As monomer components of terpene phenolic resins, i.e., phenolic compounds, for example, phenol, bisphenol A, cresol, xylenol, etc. can be cited.

[0161] "Rosin-based resin" "Rosin-based resin" means: a resin containing abietic acid, neoabietic acid, palustric acid, isopimaric acid and other rosin acid compounds as the monomer component with the largest content, and may also be their hydrogenated products or modified products. As the rosin-based resin, there is no particular limitation, and for example, natural resin rosin, rosin modified resin obtained by hydrogenating, disproportionating, dimerizing, esterifying it, etc. can be cited.

[0162] 《Phenolic resin>> "Phenolic resin" means: a resin containing phenolic compounds such as phenol and cresol as the monomer component with the largest content. As the phenolic resin, there is no particular limitation, and phenolic formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, oil-modified phenolic formaldehyde resin, etc. can be cited.

[0163] 《Softening point》 From the viewpoint of wet grip performance, the softening point of the resin component is preferably 80 °C or higher, more preferably 90 °C or higher, and further preferably 100 °C or higher. In addition, from the viewpoints of improving processability and the dispersibility of the rubber component and the filler, it is preferably 150 °C or lower, more preferably 140 °C or lower, and further preferably 130 °C or lower. In addition, the softening point of the resin is measured by the above-mentioned measurement method.

[0164] 《Content》 When containing a resin component, its content relative to 100 parts by mass of the rubber component is preferably more than 10 parts by mass, more preferably more than 20 parts by mass, and further preferably more than 30 parts by mass. On the other hand, from the viewpoint of suppressing heat generation, the content is preferably less than 100 parts by mass, more preferably less than 80 parts by mass, and further preferably 45 parts by mass or less.

[0165] (Oil) As the oil, for example, mineral oil, vegetable oil, animal oil, etc. can be cited. In addition, from the viewpoint of life cycle assessment, the waste oil after being used in a rubber mixer or an engine, and the oil refined from the waste cooking oil used in a restaurant can also be used.

[0166] In this specification, mineral oil refers to: oils derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffin-based oils (mineral oil), naphthenic oils, aromatic oils, etc. Specific examples of mineral oil include, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. In addition, due to environmental measures, oils with a lower content of polycyclic aromatic compounds (PCA) can also be used. Examples of the oils with a low PCA content include MES, TDAE, and heavy naphthenic oils.

[0167] In this specification, vegetable oil refers to: for example, it can include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc. Further, as vegetable oil, it can also include refined oils (such as salad oil) obtained by refining the above oils, transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, waste cooking oils obtained by recycling the oils used as edible oils, etc. In addition, vegetable oil can be liquid or solid at normal temperature (25°C). These can be used alone or in combination of two or more. In addition, the above vegetable oil is a component contained in the aforementioned softener and can also be used in combination with other softeners. In addition, a part of the softener component in a known rubber composition can be equivalently replaced with these vegetable oils to satisfy the relationality of the present invention.

[0168] The vegetable oil involved in this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. In addition, in this specification, acylglycerol refers to a compound in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. There is no particular limitation on the acylglycerol, and it can be any one of 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, and triacylglycerol. Further, the acylglycerol can be a monomer, a dimer, or a polymer of trimer or higher. In addition, acylglycerols of dimer or higher can be obtained by thermal polymerization, oxidative polymerization, etc. In addition, acylglycerol can be liquid or solid at room temperature (25°C).

[0169] As a method for confirming whether the rubber composition contains acylglycerol, there is no particular limitation. For example, it can be confirmed by the following 1 1H-NMR measurement. Specifically, the rubber composition compounded with triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours. After removing the rubber composition, 1H-NMR is measured at room temperature. 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm can be observed. It is speculated that these signals are from the hydrogen atoms bonded to the carbon atoms adjacent to the oxygen atom of the ester group, and it can be confirmed that acylglycerol is contained. In addition, "around" here refers to the range of ±0.10 ppm.

[0170] As the above fatty acid, there is no particular limitation, and it can be an unsaturated fatty acid or a saturated fatty acid. As the unsaturated fatty acid, monounsaturated fatty acids such as oleic acid or polyunsaturated fatty acids such as linoleic acid and linolenic acid can be cited.

[0171] Among them, as the above fatty acid, it is preferably a fatty acid with fewer double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, preferably oleic acid. As such a vegetable oil containing fatty acids, for example, a vegetable oil contained in a saturated fatty acid or a monounsaturated fatty acid can be used, or a vegetable oil modified by transesterification or the like can be used. In addition, in order to produce such a vegetable oil containing fatty acids, plants can also be improved by variety improvement, genetic modification, etc.

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

[0173] As the animal oil, fish oil, beef tallow, or an oil alcohol derived therefrom, etc. can be cited.

[0174] From the viewpoint of processability, when oil is contained, its content relative to 100 parts by mass of the rubber component is preferably more than 5 parts by mass, more preferably more than 10 parts by mass, still more preferably more than 15 parts by mass, and particularly preferably 20 parts by mass or more. Further, from the viewpoint of abrasion resistance performance, it is preferably less than 100 parts by mass, more preferably less than 50 parts by mass, still more preferably 30 parts by mass or less.

[0175] (Liquid rubber) The liquid rubber is not particularly limited as long as it is a polymer in a liquid state at normal temperature (25 °C). For example, liquid butadiene rubber (liquid BR), liquid styrene-butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene-isoprene rubber (liquid SIR), liquid farnesene rubber, etc. can be cited. These liquid rubbers can be used alone or in combination of two or more.

[0176] (Ester plasticizer) Examples of the ester plasticizer 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), dilauryl 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), etc. The ester plasticizer can be used alone or in combination of two or more.

[0177] From the viewpoint of snow performance, the content of the softener relative to 100 parts by mass of the rubber component (the total amount when multiple softeners are used in combination) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, and particularly preferably more than 50 parts by mass. Further, from the viewpoint of processability, it is preferably less than 110 parts by mass, more preferably less than 100 parts by mass, still more preferably less than 80 parts by mass, and particularly preferably 70 parts by mass or less.

[0178] (Processing aid) As processing aids, for example, fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, fatty acid esters, mixtures of fatty acid metal salts and amide esters, mixtures of fatty acid metal salts and fatty acid amides, etc. can be cited. As processing aids, for example, commercially available substances from companies such as Schill + Seilacher and Performance-Additives can be used.

[0179] When a processing aid is contained, from the viewpoint of exerting the effect of improving processability, its content relative to 100 parts by mass of the rubber component is preferably more than 0.5 part by mass, more preferably more than 1 part by mass, and further preferably more than 1.5 parts by mass. In addition, from the viewpoints of abrasion resistance and breaking strength, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and further preferably less than 5.0 parts by mass.

[0180] (Wax) The wax is not particularly limited, and any one of the substances commonly used in the tire industry can be preferably used. For example, mineral waxes, plant-derived waxes, etc. can be cited. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among them, mineral waxes are preferred. As plant-derived waxes, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As mineral waxes, for example, paraffin wax, microcrystalline wax, selected special waxes of these, etc. are cited, and paraffin wax is preferred. In addition, the wax involved in the present embodiment is a wax that does not contain stearic acid. The wax, for example, commercially available substances from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Paramelt can be used. These waxes can be used alone or in combination of two or more.

[0181] When wax is contained, from the viewpoint of the weather resistance of the rubber, its content relative to 100 parts by mass of the rubber component is preferably more than 0.5 part by mass, more preferably more than 1.0 part by mass, and further preferably more than 1.5 parts by mass. In addition, from the viewpoint of preventing tire whitening due to blooming, it is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and further preferably less than 5.0 parts by mass.

[0182] (Stearic acid) When stearic acid is contained, from the viewpoint of processability, its content relative to 100 parts by mass of the rubber component is preferably more than 0.5 part by mass, more preferably more than 1.0 part by mass, and further preferably more than 1.5 parts by mass. In addition, from the viewpoint of vulcanization rate, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and further preferably less than 5.0 parts by mass.

[0183] (Zinc oxide) When zinc oxide is contained, from the viewpoint of processability, its content relative to 100 parts by mass of the rubber component is preferably more than 0.5 part by mass, more preferably more than 1.0 part by mass, and still more preferably more than 1.5 part by mass. Further, from the viewpoint of abrasion resistance, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and still more preferably less than 5.0 parts by mass.

[0184] (Antioxidant) As the antioxidant, there is no particular limitation, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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'-dimethylxylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bis-, tris-, and polyphenol-based antioxidants such as tetrakis[methylene-3-(3,5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., etc. can be used. These antioxidants can be used alone or in combination of two or more.

[0185] When the antioxidant is contained, from the viewpoint of ozone crack resistance of the rubber, its content relative to 100 parts by mass of the rubber component (when multiple antioxidants are used in combination, it is the total amount of all) is preferably more than 1.0 part by mass, more preferably more than 2.0 part by mass, and still more preferably more than 2.5 part by mass. Further, from the viewpoints of abrasion resistance and wet grip performance, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and still more preferably less than 5.0 parts by mass.

[0186] (Vulcanizing agent) As the vulcanizing agent, sulfur can be preferably used. As sulfur, powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, etc. can be used.

[0187] When sulfur is contained, from the viewpoint of ensuring sufficient vulcanization reaction, its content relative to 100 parts by mass of the rubber component is preferably more than 0.5 part by mass, more preferably more than 1.5 parts by mass, still more preferably more than 1.0 part by mass, and particularly preferably 1.5 parts by mass or more. In addition, from the viewpoint of preventing deterioration, it is preferably less than 5.0 parts by mass, more preferably less than 3.0 parts by mass, and still more preferably less than 2.0 parts by mass. In addition, when using sulfur containing oil as the vulcanizing agent, the content of the vulcanizing agent is set as the total content of the pure sulfur component contained in the sulfur containing oil.

[0188] As vulcanizing agents other than sulfur, known organic crosslinking agents can be used. As the organic crosslinking agent, there is no particular limitation as long as it is a substance capable of forming crosslinking chains other than polysulfide bonds. For example, alkylphenol / sulfur chloride condensates, sodium 1,6-hexamethylenedithiocarbamate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, dicumyl peroxide, etc. can be cited, and 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane is preferred. These organic crosslinking agents can use commercially available substances from companies such as Tago Chemical Industry Co., Ltd., Lanxess Co., Ltd., and Flexis Co., Ltd.

[0189] (Vulcanization accelerator) There is no particular limitation on the vulcanization accelerator. For example, sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiourea-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, imidazoline-based vulcanization accelerators, xanthate-based vulcanization accelerators, caprolactam disulfide, etc. can be cited. These vulcanization accelerators can be used alone or in combination of two or more. Among them, from the viewpoint of better obtaining the desired effect, it is preferred to select one or more vulcanization accelerators from sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, and guanidine-based vulcanization accelerators.

[0190] As sulfenamide-based vulcanization accelerators, for example, N-tert-butyl-2-benzothiazole sulfenamide (TBBS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazole sulfenamide (DCBS), etc. can be cited.

[0191] As thiazole-based vulcanization accelerators, for example, 2-mercaptobenzothiazole (MBT) or its salts, di-2-benzothiazole disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, etc. can be cited.

[0192] As guanidine-based vulcanization accelerators, for example, 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatecholborate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenyl guanidine, 1,3-di-o-cumenyl-2-propionylguanidine, etc. can be cited.

[0193] As thiuram-based vulcanization accelerators, for example, tetra(2-ethylhexyl)thiuram disulfide (TOT-N), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide (TMTM), bis(pentamethylene)thiuram disulfide, bis(pentamethylene)thiuram tetrasulfide, etc. can be cited.

[0194] As thiourea-based vulcanization accelerators, for example, thiocarbamide, thiourea compounds such as diethylthiourea, dibutylthiourea, trimethylthiourea, di-o-tolylthiourea, N,N'-diphenylthiourea, trimethylthiourea, N,N'-diethylthiourea, etc. can be cited.

[0195] As dithiocarbamate-based vulcanization accelerators, for example, piperidinium pentamethylenedithiocarbamate (PPDC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), zinc dibutyldithiocarbamate (ZnBDC), zinc dibenzyldithiocarbamate (ZDBzC), zinc N-ethyl-N-phenyldithiocarbamate (ZnEPDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), sodium dibutyldithiocarbamate (NaBDC), copper dimethyldithiocarbamate (CuMDC), iron dimethyldithiocarbamate (FeMDC), tellurium methyldiethyldithiocarbamate (TeEDC), etc. can be cited.

[0196] When a vulcanization accelerator is contained, its content relative to 100 parts by mass of the rubber component (the total amount in the case of using a plurality of vulcanization accelerators) is preferably more than 3.0 parts by mass, more preferably more than 4.0 parts by mass, and further preferably 5.0 parts by mass or more. In addition, the content of the vulcanization accelerator relative to 100 parts by mass of the rubber component is preferably less than 8.0 parts by mass, more preferably less than 7.0 parts by mass, and further preferably less than 6.0 parts by mass.

[0197] In this specification, various carbon-containing materials (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may also be derived from carbon dioxide in the atmosphere. As a method for obtaining such various materials from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process of synthesizing methane from carbon dioxide can be converted.

[0198] [Manufacture] The rubber composition according to this embodiment can be manufactured by a known method. For example, it can be manufactured by kneading the above-mentioned respective components using a rubber kneading device such as an open roll mill, a closed kneader (Banbury mixer, kneader, etc.).

[0199] The kneading process includes, for example, the following basic kneading process: kneading compounding agents and additives other than the vulcanizing agent and the vulcanization accelerator, and a final kneading process (F kneading): adding the vulcanizing agent and the vulcanization accelerator to the kneaded product obtained in the basic kneading process and kneading. Further, the above basic kneading process can also be decomposed into multiple processes as needed. When decomposing the basic kneading process, the method can be: (1) a method of pre-kneading a part of the compounding agents and additives, making them into a master batch, and then adding the remaining compounding agents and additives to the obtained master batch and kneading, or it can be: (2) a method of kneading all the compounding agents and additives kneaded in the basic kneading process once and then remilling the kneaded product more than once. In the method of (1) above, the number of master batches is not limited, and it can also be two or more. In addition, when the number of master batches is two or more, it can be a manner in which all the compounding agents and additives used in the basic kneading process are distributed to any one of the master batches.

[0200] As the kneading conditions, there are no particular limitations. For example, in the basic kneading process, a method of kneading at a discharge temperature of 150 to 170 °C for 3 to 10 minutes, and in the final kneading process, kneading at 70 to 110 °C for 1 to 5 minutes can be cited. As the vulcanization conditions, there are no particular limitations. For example, a method of vulcanizing at 150 to 200 °C for 10 to 30 minutes can be cited.

[0201] The tire according to this embodiment having a tread portion composed of the rubber composition according to this embodiment can be manufactured by a conventional method. That is, the tire can be manufactured by: compounding the above-mentioned respective components as needed with respect to the rubber component, extruding and processing the prepared unvulcanized rubber composition according to the shape of the tread portion, laminating the obtained tread portion with other tire components on a tire building machine by a conventional method, forming an unvulcanized tire through forming, and heating and pressurizing the obtained unvulcanized tire in a vulcanizer. As the vulcanization conditions, there are no particular limitations. For example, a method of vulcanizing at 150 to 200 °C for 10 to 30 minutes can be cited.

[0202] [Use] The tire of the present embodiment can be used for any purpose, whether it is a pneumatic tire or a non-pneumatic tire, and can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a racing tire, a motorcycle tire, a heavy-duty tire, or a run-flat tire. In addition, a passenger car tire refers to a tire with a maximum load capacity of less than 1400 kg on the premise of being installed on a four-wheel-driving vehicle. In addition, a heavy-duty tire refers to a tire with a maximum load capacity of 1400 kg or more. In addition, the tire of the present embodiment can be used for winter tires such as studless tires in addition to all-season tires and summer tires.

Examples

[0203] The following shows examples (examples) considered to be preferred during implementation, but the scope of the present invention is not limited to the examples. Using various drugs shown below, the tires obtained according to Table 1 or Table 2 were studied, and the results calculated based on the following evaluation methods are shown in Tables 1 to 2.

[0204] [Various Drugs] NR: TSR20 SBR1: SBR manufactured by the following Production Example 1 (S-SBR, Tg: -50°C, styrene content: 25% by mass, vinyl content: 25 mol%, Mw: 1 million, non-oil-extended) SBR2: SBR manufactured by the following Production Example 2 (S-SBR, Tg: -60°C, styrene content: 20% by mass, vinyl content: 20 mol%, Mw: 700,000, non-oil-extended) SBR3: TUFDENE 3830 manufactured by Asahi Kasei Corporation (unmodified S-SBR, Tg: -35°C, styrene content: 36% by mass, vinyl content: 31 mol%, Mw: 420,000, containing 37.5 parts by mass of oil extender relative to 100 parts by mass of rubber solid content) SBR4: HPR 840 manufactured by JSR Corporation (S-SBR, Tg: -63°C, styrene content: 10% by mass, vinyl content: 42 mol%, Mw: 160,000, non-oil-extended) BR: UBEPOL BR (registered trademark) 150B manufactured by UBE Industries, Ltd. (unmodified BR, cis content: 97%, Mw: 440,000) Carbon black: Prototype (N2SA: 180 m 2 / g, average primary particle size: 16 nm) Silica: ULTRASIL VN3 manufactured by Evonik Degussa GmbH (N2SA: 175 m 2 / g, average primary particle size: 15 nm) Silane Coupling Agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa GmbH Resin Component 1: SYLVATRAXX 4150 (polyterpene resin, Mw: 2500, softening point: 115 °C) manufactured by Kraton Corporation Resin Component 2: SYLVATRAXX 4401 (α-methylstyrene resin, Mw: 700, softening point: 85 °C) manufactured by Kraton Corporation Resin Component 3: Oppera PR-395 (hydrogenated DCPD / C9 resin, resin containing dicyclopentadiene, styrene and indene as monomer components, softening point: 118 °C) manufactured by ExxonMobil Corporation Oil: VivaTec500 (TDAE oil) manufactured by H&R Co., Ltd. Wax: OZOACE 0355 (paraffin wax) manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: NOCRAC 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Antioxidant 2: NOCRAC RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Stearic Acid: Stearic Acid Beads "TSUBAKI" manufactured by NOF Corporation Zinc Oxide: Zinc Oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: HK-200-5 (powdered sulfur containing 5% oil) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization Accelerator 1: NOCCELLER CZ (N-cyclohexyl-2-benzothiazole sulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. Vulcanization Accelerator 2: NOCCELLER D (1,3-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

[0205] (Production Example 1: Production of SBR1) Cyclohexane, tetrahydrofuran, styrene and 1,3-butadiene were added to a nitrogen-purged autoclave reactor. The ratio of styrene and 1,3-butadiene was adjusted so that the styrene content was 25% by mass. After adjusting the temperature of the reactor contents to 20 °C, n-butyllithium was added and polymerization was started. Polymerization was carried out under adiabatic conditions, and the maximum temperature reached 80 °C. After confirming the formation of a polymer with an Mw of 1 million by GPC, 4 L of ethanol was injected into the polymerization solution, and the precipitate was recovered. The obtained precipitate was dried by blowing air and then dried under reduced pressure at 80 °C / 10 Pa or less until the loss on drying was 0.1% to obtain SBR1.

[0206] (Production Example 2: Production of SBR2) Cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were added to a nitrogen-purged autoclave reactor. The ratio of styrene to 1,3-butadiene was adjusted so that the styrene content was 20% by mass. After adjusting the temperature of the reactor contents to 20 °C, n-butyllithium was added to initiate polymerization. Polymerization was carried out under adiabatic conditions, and the maximum temperature reached 80 °C. After confirming the formation of a polymer with an Mw of 700,000 by GPC, 4 L of ethanol was injected into the polymerization solution, and the precipitate was recovered. The obtained precipitate was dried by blowing air and then dried under reduced pressure at 80 °C / 10 Pa or less until the weight loss on drying was 0.1% to obtain SBR2.

[0207] (Examples and Comparative Examples) According to the compounding formula shown in Table 1 or Table 2, using a 1.7 L closed Banbury mixer, the reagents other than sulfur and vulcanization accelerators were kneaded for 4 minutes at a discharge temperature of 160 °C to obtain a kneaded product. Then, using an open mill, sulfur and vulcanization accelerators were added to the obtained kneaded product and kneaded for 4 minutes until the temperature reached 105 °C to obtain an unvulcanized rubber composition. Using the obtained unvulcanized rubber composition, it was formed according to the shape of the tread portion and adhered together with other tire components to produce an unvulcanized tire, which was vulcanized at 170 °C to obtain each test tire (size: 205 / 65R15, rim: 15×6JJ, internal pressure: 230 kPa).

[0208] (Determination of Acetone Extract Amount (AE)) For the rubber test pieces cut from the tread portions of each test tire, the AE amount was measured separately. The AE amount can be obtained by immersing each rubber test piece in acetone at room temperature (about 25 °C) for 24 hours to extract the soluble components, measuring the mass of each test piece before and after extraction, and calculating using the following formula. Acetone extract amount (%) = { (mass of vulcanized rubber test piece before extraction - mass of vulcanized rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0209] (Temperature Distribution Curve of tanδ) For the rubber test pieces cut from the tread portions of each test tire, using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho Co., Ltd., in the temperature range from -20 °C to -70 °C, the temperature distribution curve of tanδ was measured under the conditions of a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±0.5%, and a heating rate of 2 °C / min. At the same time, based on the obtained temperature distribution curve of tanδ, the tanδ and the half-peak width at the peak position in the range of -20 °C to -70 °C were measured.

[0210] (Measurement of tanδ at 0 °C) From the tread surface of each test tire, with the circumferential direction of the tire as the long side and the radial direction of the tire as the thickness direction, cut and fabricate specimens with a length of 20 mm × width of 4 mm × thickness of 1 mm. For each rubber test piece, use the EPLEXOR series manufactured by GABO Co., Ltd. to measure the loss tangent (tanδ) under the conditions of a temperature of 0°C, a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of ±2.5%.

[0211] <-10°C tanδ> From the tread surface of each test tire, with the circumferential direction of the tire as the long side and the radial direction of the tire as the thickness direction, cut and fabricate specimens with a length of 20 mm × width of 4 mm × thickness of 1 mm. For each rubber test piece, use the EPLEXOR series manufactured by GABO Co., Ltd. to measure the loss tangent (tanδ) under the conditions of a temperature of -10°C, a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of ±2.5%.

[0212] <Snow performance> Install each test tire on the four wheels of an FF passenger car with a displacement of 2000 cc, and on a snow-covered road surface, measure the braking distance starting from the braking point at a speed of 15 km / h. Set the braking distance of the test tire in the reference comparative example (Comparative Example 10) as 100, and according to the following calculation formula, express the snow performance of each tire as an index. The larger the index, the better the snow performance. (Snow performance index) = (Braking distance of the tire in the reference comparative example) / (Braking distance of each test tire) × 100

[0213] <Wet grip performance> Install each test tire on the four wheels of an FF passenger car with a displacement of 2000 cc, and on a wet asphalt road surface, measure the braking distance starting from the braking point at a speed of 100 km / h. Set the braking distance of the test tire in the reference comparative example (Comparative Example 10) as 100, and according to the following calculation formula, express the wet grip performance of each tire as an index. The larger the index, the better the wet grip performance. (Wet grip performance index) = (Braking distance of the tire in the reference comparative example) / (Braking distance of each test tire) × 100

[0214] <Comprehensive performance> The sum of the above snow performance and wet grip performance is expressed as the comprehensive performance index.

[0215]

Table 1

[0216]

Table 2

[0217] <Embodiment> An embodiment of the present invention is shown below, for example. 〔1〕A tire, characterized in that the tread surface has one or more circumferential grooves, the tread surface is composed of a rubber composition containing a rubber component and silica, the rubber component contains an isoprene-based rubber and a styrene-butadiene rubber, the content of the isoprene-based rubber in the rubber component is 40% by mass or more, relative to 100 parts by mass of the rubber component, the content of the silica is 70 parts by mass or more, the styrene content S1 (%) of the styrene-butadiene rubber is 30 or less, the acetone extraction amount AE (%) of the rubber composition is greater than 17.0, the half-peak width of the peak in the tanδ temperature distribution curve of the rubber composition in the range of -20°C to -70°C is 45°C or more, when the groove depth at the deepest part of the circumferential groove is set to H (mm), when the tanδ of the rubber composition at -10°C is set to -10°C tanδ, -10°C tanδ × H is 1.7 or more. 〔2〕The tire according to the above 〔1〕, wherein the total styrene amount S2 (%) in the rubber component is 15 or less. 〔3〕The tire according to the above 〔1〕 or 〔2〕, wherein the rubber composition contains a resin component containing dicyclopentadiene, styrene, and indene as monomer components. 〔4〕The tire according to any one of the above 〔1〕 to 〔3〕, wherein -10°C tanδ is 0.30 or more. 〔5〕The tire according to any one of the above 〔1〕 to 〔4〕, wherein -10°C tanδ × H is 2.0 or more. 〔6〕The tire according to any one of the above 〔1〕 to 〔5〕, wherein the acetone extraction amount of the rubber composition is greater than 20.0% by mass. 〔7〕The tire according to any one of the above 〔1〕 to 〔6〕, wherein the tanδ (0°C tanδ) of the rubber composition at 0°C is 0.50 or more. 〔8〕The tire according to any one of the above 〔1〕 to 〔7〕, wherein when the total thickness of the tread surface is set to T (mm), -10°C tanδ × T is 1.5 or more and 3.5 or less. 〔9〕The tire according to any one of the above 〔1〕 to 〔8〕, wherein the rubber composition contains 20 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component. 〔10〕The tire according to any one of the above 〔1〕 to 〔9〕, wherein when the ground contact area ratio of the tread portion is set to R, S1 × R is 10.0. 〔11〕The tire according to any one of the above 〔1〕 to 〔10〕, wherein when the tire weight is set to G (kg), S1 / G is 3.0 or less. 〔12〕The tire according to any one of the above 〔1〕 to 〔11〕, wherein the number of the circumferential grooves is 3 or more, and the tread portion has: a pair of shoulder ground contact portions divided by a pair of outermost circumferential grooves located at the outermost ends in the tire width direction, and two or more central ground contact portions located between the pair of shoulder ground contact portions, and the groove width of at least one of the pair of outermost circumferential grooves is narrower than the groove width of at least one of the circumferential grooves other than the pair of outermost circumferential grooves. 〔13〕The tire according to any one of the above 〔1〕 to 〔12〕, wherein the rubber composition contains 30 parts by mass or more and 70 parts by mass or less of a softening agent with respect to 100 parts by mass of the rubber component. 〔14〕The tire according to any one of the above 〔1〕 to 〔13〕, wherein S1 is 25 mass% or less. 〔15〕The tire according to any one of the above 〔1〕 to 〔14〕, wherein S1 is 15 mass% or less.

Claims

1. A tire, characterized in that: It is a tire having a tread portion. The tread portion has one or more circumferential grooves, The tread portion is composed of a rubber composition containing a rubber component and silica. The rubber component contains isoprene-based rubber and styrene-butadiene rubber. The content of the isoprene-based rubber in the rubber component is 40% by mass or more, The content of the silica is 70 parts by mass or more relative to 100 parts by mass of the rubber component. The styrene content S1 of the styrene butadiene rubber is less than 30, and the unit of S1 is mass %. The acetone extractable amount AE of the rubber composition is greater than 17.0, and the unit of AE is mass %. The half-peak width of the peak of the tan δ temperature distribution curve of the rubber composition in the range of -20°C to -70°C is 45°C or more, The groove depth of the deepest part of the circumferential groove is H. When the tan δ of the rubber composition at -10°C is set to -10°C tan δ, -10℃tanδ×H is 1.7 or more, The unit of H is mm.

2. The tire according to claim 1, wherein: The total styrene content S2 in the rubber component is 15 or less, and the unit of S2 is mass %.

3. The tire according to claim 1 or 2, wherein: The rubber composition contains a resin component including dicyclopentadiene, styrene, and indene as monomer components.

4. The tire according to claim 1 or 2, wherein: -10°C tanδ is 0.30 or more.

5. The tire according to claim 1 or 2, wherein: -10°C tanδ×H is 2.0 or more.

6. The tire according to claim 1 or 2, wherein: The rubber composition has an acetone extractable amount greater than 20.0 mass %.

7. The tire according to claim 1 or 2, wherein: The rubber composition has a tan δ at 0°C, that is, tan δ at 0°C of 0.50 or more.

8. The tire according to claim 1 or 2, wherein: When the total thickness of the tread portion is represented by T, -10°C tanδ×T is greater than or equal to 1.5 and less than or equal to 3.5, where the unit of T is mm.

9. The tire according to claim 1 or 2, wherein: The rubber composition contains 20 parts by mass or more of carbon black based on 100 parts by mass of the rubber component.

10. The tire according to claim 1 or 2, wherein: When the contact area ratio of the tread portion is represented by R, S1×R is equal to or greater than 10.

0.

11. The tire according to claim 1 or 2, wherein: When the tire weight is G, S1 / G is less than or equal to 3.0, and the unit of G is kg.

12. The tire according to claim 1 or 2, wherein: The number of the circumferential grooves is 3 or more, and the tread portion has: a pair of shoulder land portions divided by a pair of outermost circumferential grooves located at the outermost ends in the tire width direction, and two or more central land portions located between the pair of shoulder land portions, The groove width of at least one of the pair of outermost circumferential grooves is narrower than the groove width of at least one of the circumferential grooves other than the pair of outermost circumferential grooves.

13. The tire according to claim 1 or 2, wherein: The rubber composition contains 30 parts by mass or more and 70 parts by mass or less of a softener relative to 100 parts by mass of the rubber component.

14. The tire according to claim 1 or 2, wherein: S1 is 25 mass % or less.

15. The tire according to claim 1 or 2, wherein: S1 is 15 mass % or less.

16. The tire according to claim 1 or 2, wherein: The content of the silica is less than 200 parts by mass based on 100 parts by mass of the rubber component.

17. The tire according to claim 1 or 2, wherein: The rubber composition has an acetone extractable amount AE of less than 35.0, where the unit of AE is mass %.

18. The tire according to claim 1 or 2, wherein: -10°C tanδ×H is 3.0 or less.

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