Tire

Abstract

The present invention addresses the problem of providing a tire capable of improving the overall performance of low fuel consumption performance and wear resistance performance. [Solution] A tire provided with a tread portion having at least one rubber layer, in which the ratio (G / WL) of the tire weight G (kg) to the tire maximum load capacity WL (kg) is 0.0170 or less, a first layer constituting the tread is configured from a rubber composition containing a rubber component and a filler, the filler contains a sustainable filler, and R represents the ground contact ratio on the ground contact surface of the tread portion, and R represents the ground contact ratio on the ground contact surface of the tread portion, the ratio (G / WL) of the rubber component to the maximum load capacity WL (kg) of the rubber component to the maximum load capacity WL (kg) of the rubber component to the maximum load capacity WL (kg) of the rubber component. When the total content of the filler per 100 parts by mass of the rubber component in the rubber composition is F (parts by mass), the product (R * F) of R and F is greater than 42.0.

Description

Technical Field

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

[0002] On the tread surface of a tire, in addition to low fuel consumption performance (rolling resistance characteristics), performance such as abrasion resistance and wet skid resistance is also required. Performance improvement is carried out by methods such as designing the rubber composition and filler for the tread portion (for example, Patent Documents 1 and 2), and there is still room for improvement in improving the balance of these performances well.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a tire capable of improving the comprehensive performance of low fuel consumption performance and abrasion resistance.

Means for Solving the Problems

[0005] In recent years, tires have been lightened in order to reduce the rolling resistance of the tires. In order to lighten the tire, reducing the thickness of the tread portion is considered, but there is a concern that the tire life may be shortened due to abrasion. In addition, since the rubber for low fuel consumption generates little heat, it has a tendency to deform immediately when impacted and is easily subjected to rubber damage.

[0006] The present invention relates to a tire having a tread portion with at least one rubber layer. The ratio (G / W L (kg)) of the tire weight G (kg) to the maximum load capacity W L ) of the tire is 0.0170 or less. The first layer constituting the tread is composed of a rubber composition containing a rubber component and a filler, the filler contains a sustainable filler, and when the grounding ratio of the grounding surface of the tread portion is R and the total content of the filler is F (parts by mass) with respect to 100 parts by mass of the rubber component in the rubber composition, the product (R×F) of R and F is greater than 42.0.

Effects of the Invention

[0007] According to the present invention, a tire is provided that can improve the comprehensive performance of low fuel consumption performance and abrasion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Figure 1

[0009] A tire according to an embodiment of the present invention is a tire having at least a tread portion with one rubber layer, and the ratio (G / W L )(kg) of the tire weight G (kg) to the maximum load capacity W L ) of the tire is 0.0170 or less. The first layer constituting the tread is composed of a rubber composition containing a rubber component and a filler, and the filler contains a sustainable filler. When the grounding ratio of the grounding surface of the tread portion is R and the total content of the filler relative to 100 parts by mass of the rubber component in the rubber composition is F (parts by mass), the product (R×F) of R and F is greater than 42.0.

[0010] Regarding the reason for the improvement of the comprehensive performance of the low fuel consumption performance and wear resistance performance of the tire of the present invention, although not intending to be theoretically restricted, there are the following considerations.

[0011] It is considered that if the tire section width Wt is increased, the maximum load capacity W L increases. Therefore, by setting G / W L to 0.0160 or less, the improvement of the low fuel consumption effect brought about by the weight reduction of the tire is achieved.

[0012] The sustainable filler can exhibit a wide particle size distribution. It is considered that due to the influence of the small particle size part of such a filler, the viscosity increases, so the shear force required for filler dispersion is large, and the filler dispersibility is improved.

[0013] In addition, by increasing the total content F of the filler, the breaking strength of the rubber can be ensured. It is further considered that by increasing the grounding ratio R, the pattern rigidity and wear energy are increased. It is considered that thus, by making the product of R and F above a certain value, the wear resistance performance can be improved.

[0014] And it is considered that through their synergy, the improvement of the comprehensive performance of the low fuel consumption performance and wear resistance performance of the tire can be achieved.

[0015] From the perspective of building a sustainable society, the filler preferably contains silica made from biomass materials.

[0016] From the perspective of building a recycling-based society, the filler preferably contains recycled carbon black.

[0017] The tanδ (30°C tanδ) of the rubber composition at 30°C is preferably 0.20 or less.

[0018] It is considered that by making the 30°C tanδ within the above range, the low fuel consumption performance can be improved.

[0019] (R×F) / (G / W L ) is preferably greater than 3000.

[0020] It is considered that by making (R×F) / (G / W L ) within the above range, the abrasion resistance can be improved.

[0021] When the complex elastic modulus of the rubber composition at 30 °C is 30 °C E* (MPa), the product of R and 30 °C E* (R×30 °C E*) is preferably greater than 2.5.

[0022] It is considered that by making R×30 °C E* within the above range, the abrasion resistance can be improved.

[0023] From the viewpoint of the effects of the present invention, the total styrene content S in the rubber component is preferably 25% by mass or less.

[0024] The product of R and S (R×S) is preferably 15.0 or less.

[0025] It is considered that by making R×S within the above range, the low fuel consumption performance can be improved.

[0026] S / 30 °C E* is preferably 6.0 or less.

[0027] If 30 °C E* is small, the tread rubber deforms greatly. On the other hand, by reducing the total styrene content S in the rubber component, the heat generation during the deformation of the tread rubber can be suppressed. It is considered that thus, by reducing the total styrene content S as 30 °C E* decreases, the low fuel consumption performance and the breaking strength of the tread rubber are further improved.

[0028] From the viewpoint of the effects of the present invention, the rubber component preferably contains an isoprene rubber.

[0029] From the viewpoint of the effects of the present invention, the rubber component preferably contains a styrene-butadiene rubber having a styrene content of 30% by mass or less.

[0030] When the modulus at 200% elongation of the rubber composition is M 200 (MPa), M 200 of the rubber composition, 30 °C E* and 30 °C tan δ preferably satisfy the relational expression M 200 ×30 °C E* / 30 °C tan δ ≥ 100.

[0031] It is considered that by making M 200 ×30 °C E* / 30 °C tan within the above range, the low fuel consumption performance and the abrasion resistance can be improved with good balance.

[0032] From the viewpoint of building a sustainable society, the rubber composition preferably contains vegetable oil.

[0033] <Definition> "Tread face" is the part that forms the ground contact surface of the tire. When a component that forms the tire skeleton, such as steel and fabric materials passing through the belt layer, belt reinforcing layer, and carcass layer, is present in the tire radius direction cross-section, it is a component that is more outside in the tire radius direction than them.

[0034] "Normal state" means a no-load state in which the tire is mounted on a normal rim and filled with air at normal internal pressure.

[0035] "Dimensions of each part of the tire", unless otherwise specified, for components appearing on the outer surface of the tire, are values specified in the normal state. On the other hand, for components existing inside the tire and in the tire cross-section, for example, the tire is cut by a plane containing the tire rotation axis, and the cut tire piece is held in the state of the rim width of the normal rim and the specified value.

[0036] "Normal rim" means, in the specification system including the specifications on which the tire is based, the rim specified for each tire by that specification. For example, if it is JATMA (Japan Automobile Tire Association), it is the standard rim under the applicable dimensions described in the "JATMA Year Book (JATMA YEAR BOOK)". If it is ETRTO (The European Tyre and Rim Technical Organisation), it is the "Measuring Rim" described in the "Standards Manual". If it is TRA (The Tire and Rim Association, Inc.), it is the "Design Rim" described in the "Year Book". Refer to the order of JATMA, ETRTO, TRA. When referring, if there are applicable dimensions, follow their specifications. In addition, for a tire not specified by the above specifications, it means the rim with the smallest rim width among the rims with the smallest diameter that can be mounted on the tire and can maintain the internal pressure (that is, no air leakage occurs between the rim / tire).

[0037] "Normal internal pressure" means the air pressure specified for each tire in the specification system that includes the specifications on which the tire is based. For example, in the case of JATMA, it is the "maximum air pressure"; in the case of ETRTO, it is the "Inflation Pressure"; in the case of TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". The same applies to the case of a normal rim. Refer to the order of JATMA, ETRTO, and TRA. When referring, if there is an applicable size, follow its specifications. It should be noted that when the tire is not determined by the said specifications, it refers to the normal internal pressure (where it is 250 kPa or more) of other tire sizes (where it is specified in the specifications) recorded with the said normal rim as the standard rim. When the normal internal pressure of 250 kPa or more is recorded in multiple places, it refers to the minimum value among them.

[0038] "Normal load" means the load specified for each tire in the specification system that includes the specifications on which the tire is based. For example, in the case of JATMA, it is the "maximum load capacity"; in the case of ETRTO, it is the "Load Capacity"; in the case of TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". The same applies to the cases of a normal rim and normal internal pressure. Refer to the order of JATMA, ETRTO, and TRA. When referring, if there is an applicable size, follow its specifications. And when the tire is not determined by the said specifications, the maximum load capacity W calculated separately L is the normal load.

[0039] "Maximum load capacity W L " is calculated by the following formula. "V" is the imaginary volume of the tire (mm 3 ), "Dt" is the outer diameter of the tire in the normal state (mm), "Ht" is the height of the tire cross-section in the radial direction of the tire on the tire cross-section obtained by the plane including the tire rotation axis (mm), and "Wt" is the width of the tire cross-section in the normal state (mm). When the rim diameter of the tire is R, Ht can be obtained by (Dt - R) / 2. Wt is the value obtained by removing patterns, characters, etc. on the tire side. In addition, the maximum load capacity is synonymous with the said normal load.

[0040]

Equation 1

[0041] "The tire weight G (kg)" means the weight of the tire monomer excluding the weight of the rim. On the other hand, when the tire inner cavity part has a sound-absorbing material, a sealant, a sensor, etc., G is the weight including these.

[0042] Including circumferential grooves and transverse grooves, the "groove" means a depression with a width of at least more than 2.0 mm.

[0043] The "contact area" is the tread area obtained from the contour when the tire is pressed against the ground. After mounting the tire on a regular rim, loading the regular internal pressure, standing for 24 hours at 25°C, inking the tire tread surface, loading the regular load (maximum load capacity) on the tire, and vertically pressing it against thick paper (camber angle is 0°), it is obtained by printing the ink. The area of the contact area is called the total contact area. The total contact area can be calculated as follows: rotate the tire every 72°, perform the above printing operation at a total of 5 places, and take the average of the 5 areas obtained.

[0044] The "effective contact area" is the tread area of the tire in contact with the ground when the tire is pressed against the ground. After mounting it on a regular rim, loading the regular internal pressure, standing for 24 hours at 25°C, inking the tire tread surface, loading the regular load (maximum load capacity) on the tire, and vertically pressing it against thick paper (camber angle 0°), it is obtained by printing the ink. The area of the effective contact area is the effective contact area. The effective contact area can be calculated as follows: rotate the tire every 72°, perform the above printing operation at a total of 5 places, and take the average of the 5 areas obtained.

[0045] The "contact ratio R" is calculated from the total contact area of the contact area and the effective contact area of the effective contact area by the following formula. (Contact ratio) = (Effective contact area / Total contact area)

[0046] The "overall thickness of the tread part" means the overall thickness of the tread part on the tire equatorial plane in the cross-section obtained by cutting the tire with a plane including the tire rotation axis. In addition, the inner end in the tire radius direction of the overall thickness of the tread part is the inner interface of the rubber composition constituting the tread part. When the tire has a belt reinforcing layer, a belt layer, and a carcass layer, it is the overall thickness of the rubber layer that is more on the outer side in the tire radius direction than the outermost layer in the tire radius direction among them. In addition, when there is a circumferential groove on the tire equatorial plane, measure the overall thickness of the tread part as the tire with the groove filled.

[0047] "The thickness of each rubber layer constituting the tread portion" is the thickness of each rubber layer on the equatorial plane of the tire in a cross section obtained by cutting the tire with a plane containing the rotation axis of the tire, and is the average thickness of the tread portion obtained at 5 positions by rotating the tire 72° each time in the circumferential direction. For example, the thickness of the first layer refers to the straight-line distance in the radial direction of the tire from the outermost surface of the tread to the inner radial interface of the first layer on the equatorial plane of the tire. In addition, when there is a circumferential groove on the equatorial plane of the tire, the thickness of each rubber layer constituting the tread portion is the thickness of each rubber layer on the central part in the tire width direction of the land portion closest to the equatorial plane of the tire. "The land portion closest to the equatorial plane of the tire" refers to the land portion of the circumferential groove existing on the equatorial plane of the tire and having the groove edge closest to the equatorial plane of the tire. When such a land portion exists on both sides in the tire width direction, the thickness of each rubber layer constituting the tread portion is the average thickness of each rubber layer on the central part in the tire width direction of the two land portions. Furthermore, when a conducting component or the like exists on the land portion on the tire equatorial plane and the interface is unclear, the interface blocked by the conducting component or the like is virtually connected and measured.

[0048] The term "sustainable filler" refers to a filler made from biomass materials or a filler obtained from a used article containing a filler.

[0049] "Plasticizer" refers to a material that gives plasticity to the rubber component and is extracted from the rubber composition with acetone. Plasticizers include plasticizers that are liquid at 25°C and plasticizers that are solid at 25°C. Among them, wax and stearic acid commonly used in the tire industry are not included.

[0050] The "content of plasticizer" includes the amount of plasticizer contained in the extended rubber component that has been extended in advance by a plasticizer such as oil, resin component, liquid rubber component, etc. In addition, the same applies to the content of oil, the content of resin component, and the content of liquid rubber. For example, when the extended component is oil, the extended oil is included in the content of the oil.

[0051] <Measurement method> The “thickness of each rubber layer constituting the tread portion” is measured in a state where the tire is cut along a plane including the tire rotation axis so that the width of the bead portion matches the normal rim width.

[0052] "30°C tanδ" is the loss tangent measured using a dynamic viscoelasticity measuring device (e.g., EPLEXOR series manufactured by GABO) at a temperature of 30°C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and a tensile mode. The sample for the loss tangent measurement is a vulcanized rubber composition of 20 mm in length, 4 mm in width, and 1 mm in thickness. When cutting out from a tire for production, the tire is cut out from the tread portion of the tire with the tire circumferential direction as the long side and the tire radial direction as the thickness direction.

[0053] "30℃E*" is the complex elastic modulus measured under the conditions of a temperature of 30°C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and a tensile mode using a dynamic viscoelasticity measuring device (for example, the EPLEXOR series manufactured by GABO). The sample for this measurement is produced in the same manner as in the case of 30°C tanδ.

[0054] "Modulus at 200% elongation (M 200 )" is the tensile stress (MPa) at 200% elongation in the grain direction (the calendering direction when forming a rubber sheet by extrusion or shearing) measured at 23°C in an atmosphere based on JIS K 6251:2017 under the condition of a tensile speed of 3.3 mm / second. M 200 The sample for measurement is a dumbbell-shaped No. 7 vulcanized rubber test piece with a thickness of 1 mm. When cutting and producing from a tire, it is cut from the tread surface of the tire in such a way that the circumferential direction of the tire is the tensile direction and the radial direction of the tire is the thickness direction.

[0055] "Styrene content" is a value calculated by pyrolysis gas chromatography, and is applicable to, for example, rubber components having repeating units of styrene from SBR or the like. In addition, in this specification, "pyrolysis gas chromatography" refers to a method of heating a sample through a pyrolysis device, separating each component contained in the gas phase components generated by this heating through a separation column, and analyzing each separately separated component.

[0056] "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, for example, rubber components having repeating units of butadiene from SBR, BR, or the like.

[0057] "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, for example, rubber components having repeating units of butadiene from BR or the like.

[0058] "Total styrene amount in the rubber component" means the total content (mass%) of styrene units contained in 100 mass% of the rubber component. For each rubber component, the value obtained by multiplying the styrene content (mass%) by the mass fraction in the rubber component is calculated, and these values are added together. Specifically, it is calculated by Σ (styrene content (mass%) of each rubber containing styrene units × content (mass%) of each rubber containing styrene units in the rubber component / 100).

[0059] "Weight-average molecular weight (Mw)" can be determined by standard polystyrene conversion based on the measured values of gel permeation chromatography (GPC) (e.g., GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKgel SuperMultipore HZ-M manufactured by Tosoh Corporation). For example, it is applicable to SBR, BR, plasticizers, etc.

[0060] "The nitrogen adsorption specific surface area (N2SA) of carbon black" is measured based on JIS K 6217-2:2017. "The nitrogen adsorption specific surface area (N2SA) of silica" is measured by the BET method based on ASTM D3037-93.

[0061] "Particle size distribution" is measured using a laser diffraction particle size distribution measuring device (e.g., SALD-2300 manufactured by Shimadzu Corporation), and is applicable to silica, carbon black, etc.

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

[0063] "Softening point of the resin component" is the temperature at which the ball drops, measured using a ring-and-ball softening point measuring device according to the softening point specified in JIS K 6220-1:20157.7.

[0064] The manufacturing sequence of the tire according to one embodiment of the present invention will be described in detail below. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of the technology of the present invention to this description.

[0065] [Tire] In the tire according to this embodiment, from the perspective of the effects of the present invention, the ratio of the tire weight G (kg) to the maximum load capacity W L (kg) (G / W L ) is 0.0170 or less, preferably 0.0165 or less, more preferably 0.0155 or less, further preferably 0.0145 or less, further preferably 0.0140 or less, and particularly preferably 0.0135 or less. On the other hand, this G / W LThe lower limit value is not particularly limited from the perspective of the effects of the present invention. For example, it can be 0.0110 or more, 0.0115 or more, 0.0120, 0.0125 or more. In addition, the tire weight G can be changed by a conventional method, that is, it can be increased by increasing the tire specific gravity or increasing the thickness of each tire component, and can be decreased by the opposite method.

[0066] From the perspective of better exerting the effects of the present invention, the maximum load capacity W L (kg) is preferably 300 or more, more preferably 400 or more, further preferably 450 or more, and particularly preferably 500 or more. In addition, from the perspective of better exerting the effects of the present invention, the maximum load capacity W L (kg) can be, for example, 1300 or less, 1250 or less, 1200 or less, 1000 or less, 900 or less, 800 or less, 700 or less. In addition, the maximum load capacity W L can be increased by increasing the imaginary volume V of the space occupied by the tire, and can also be decreased by the opposite method.

[0067] The ground contact ratio R on the ground contact surface of the tread portion is preferably 0.50 or more, more preferably 0.55 or more, further preferably 0.60 or more, and particularly preferably 0.63 or more. In addition, the ground contact ratio R is preferably 0.85 or less, more preferably 0.80 or less, and further preferably 0.75 or less.

[0068] The tread portion according to the present embodiment has at least one rubber layer. The tread portion according to the present embodiment can be a tread portion composed of a single rubber layer, or can be a tread portion having a first layer forming the tread on the outer surface and one or more rubber layers (inner rubber layers) existing between the first layer and the belt layer.

[0069] The thickness of the first layer forming the tread relative to the thickness of the entire tread portion can be, for example, 30% or more, 50% or more, 70% or more, 90% or more, and the tread portion can also be composed only of the first layer forming the tread.

[0070] From the perspective of the effects of the present invention, the 30°C E* of the rubber composition constituting the first layer is preferably 3.0 MPa or more, more preferably 3.5 MPa or more, further preferably 4.0 MPa or more, and particularly preferably 4.5 MPa or more. In addition, the 30°C E* of this rubber composition is preferably 15.0 MPa or less, more preferably 13.0 MPa or less, further preferably 11.0 MPa or less, and particularly preferably 10.0 MPa or less. In addition, the 30°C E* of the rubber composition can be appropriately adjusted according to the types and mixing amounts of the rubber components, vulcanized rubber particles, resin components, oils, etc. described later.

[0071] From the perspective of the effects of the present invention, the tanδ at 30°C of the rubber composition constituting the first layer is preferably 0.30 or less, more preferably 0.27 or less, further preferably 0.25 or less, still further preferably 0.22 or less, yet further preferably 0.20 or less, and particularly preferably 0.18 or less. In addition, the tanδ at 0°C of the rubber composition is preferably 0.06 or more, more preferably 0.08 or more, and further preferably 0.10 or more. In addition, the tanδ at 30°C of the rubber composition can be appropriately adjusted by the types and mixing amounts of the rubber component, vulcanized rubber particles, resin component, oil, etc. described below.

[0072] From the perspective of the effects of the present invention, the rubber composition M constituting the first layer 200 is preferably 3.0 MPa or more, more preferably 3.5 MPa or more, further preferably 4.0 MPa or more, and particularly preferably 4.5 MPa or more. On the other hand, the rubber composition M 200 has no particular limitation on the upper limit value, and is preferably 15.0 MPa or less, more preferably 13.0 MPa or less, and further preferably 11.0 MPa or less. In addition, the rubber composition M 200 can be appropriately adjusted according to the types and mixing amounts of the rubber component, vulcanized rubber particles, resin component, oil, etc. described below.

[0073] From the perspective of abrasion resistance performance, the product (R×F) of the ground contact ratio R and the total content F (parts by mass) of the filler relative to 100 parts by mass of the rubber component in the rubber composition is greater than 42.0, preferably greater than 44.0, more preferably greater than 46.0, and further preferably greater than 48.0. On the other hand, there is no particular limitation on the upper limit value of R×F, and it is preferably less than 75.0, more preferably less than 70.0.

[0074] The product (R×30°C E*) of the ground contact ratio R and the 30°C E* (MPa) of the rubber composition constituting the first layer is preferably greater than 2.0, more preferably greater than 2.5, further preferably greater than 3.0, and particularly preferably greater than 3.5. On the other hand, there is no particular limitation on the upper limit value of R×30°C E*, and it is preferably less than 14.0, more preferably less than 12.0, further preferably less than 10.0, and particularly preferably less than 8.0.

[0075] The ratio (S / 30°C E*) of the total styrene amount S (mass%) in the rubber component to the 30°C E* of the rubber composition constituting the first layer is preferably 6.0 or less, more preferably 5.5 or less, further preferably 5.0 or less, and particularly preferably 4.5 or less. In addition, the lower limit value of S / 30°C E* has no particular limitation from the perspective of the effects of the present invention, and is preferably greater than 0, more preferably 0.3 or more, further preferably 0.6 or more, and particularly preferably 0.9 or more.

[0076] The product (R×S) of the ground contact ratio R and the total styrene content S (mass %) in the rubber component is preferably 24.0 or less, more preferably 21.0 or less, still more preferably 18.0 or less, and particularly preferably 15.0 or less. On the other hand, the lower limit value of R×S is not particularly limited, preferably 1.0 or more, more preferably 2.0 or more, still more preferably 3.0 or more, and particularly preferably 4.0 or more.

[0077] The product (30°C tanδ×30°C E*×t1) of 30°C tanδ, 30°C E*, and the thickness t1 of the first layer of the tread is preferably less than 8.25, more preferably less than 8.00, still more preferably 7.75. On the other hand, 30°C tanδ×30°C E*×t1 is preferably greater than 2.00, more preferably greater than 2.50, still more preferably greater than 3.00.

[0078] (R×F) / (G / W L ), is preferably greater than 3000, more preferably greater than 3500. On the other hand, the upper limit value of (R×F) / (G / W L ) is not particularly limited, preferably less than 5000, more preferably less than 4500.

[0079] M 200 ×30°C E* / 30°C tanδ is preferably 100 or more, more preferably 120 or more, still more preferably 140 or more, and particularly preferably 160 or more. On the other hand, M 200 ×30°C E* / 30°C tanδ has no particular upper limit, preferably 800 or less, more preferably 700 or less, still more preferably 600 or less, and particularly preferably 500 or less.

[0080] [Rubber composition] The tire according to the present embodiment can more effectively improve the comprehensive performance of low fuel consumption performance and abrasion resistance performance through the cooperation of the structures of the aforementioned tire and tread, and the physical properties of the rubber composition constituting the tread. Hereinafter, the rubber composition constituting the first layer will be described.

[0081] <Rubber component> The rubber composition according to this embodiment preferably uses a diene rubber as the rubber component. Examples of the diene rubber include isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), etc. These diene rubbers may be modified rubbers treated with a modifying group capable of interacting with fillers such as carbon black and silica, or may be hydrogenated rubbers obtained by hydrogenating a part of the unsaturated bonds. The diene rubber may be used alone or in combination of two or more. In addition, as the diene rubber, an extended rubber preliminarily extended with a plasticizer described later may also be used.

[0082] The content of the diene rubber in the rubber component is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. In addition, the rubber component may be composed only of the diene rubber.

[0083] As the diene rubber component, at least one selected from the group consisting of isoprene rubber, styrene-butadiene rubber (SBR), and butadiene rubber (BR) is preferably used. The rubber component preferably contains SBR, more preferably contains SBR and isoprene rubber and / or BR, still more preferably contains isoprene rubber, BR, and SBR, and may also be a rubber component composed only of isoprene rubber, SBR, and BR.

[0084] (Isoprene rubber) The isoprene rubber is not particularly limited, and examples thereof include natural rubber (NR), isoprene rubber (IR), and modified natural rubber. Examples of NR include SIR20, RSS#3, TSR20, etc. Examples of IR include IR2200, etc. Examples of the modified natural rubber include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, grafted natural rubber, etc. These isoprene rubbers may be used alone or in combination of two or more.

[0085] From the viewpoint of the effects of the present invention, the content of the isoprene rubber in the rubber component is preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, and particularly preferably 60% by mass or less. In addition, the lower limit value of this content is not particularly limited, and may be, for example, 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more.

[0086] (BR) There is no particular limitation on BR, and 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 general products in the tire industry, can be used. These BRs can be used alone or in combination of two or more.

[0087] For high-cis BR, for example, those commercially available from Zeon Corporation, Ube Industries, Ltd., JSR Corporation, etc. can be used. The wear resistance performance can be improved by containing high-cis BR. The cis content of high-cis BR is preferably 95 mol% or more, more preferably 96 mol% or more, and further preferably 97 mol% or more. In addition, the cis content of BR is measured by the said measurement method.

[0088] As the modified BR, it is preferably a modified butadiene rubber (modified BR) in which the terminal and / or the main chain is modified with a functional group containing at least one element selected from the group consisting of silicon, nitrogen, and oxygen.

[0089] As other modified BRs, those obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, and further, the terminals of the modified BR molecules are bonded by a tin-carbon bond (tin-modified BR), etc. can be mentioned. In addition, the modified BR can be either unhydrogenated BR or hydrogenated BR.

[0090] From the viewpoint of wear resistance performance, the weight-average molecular weight (Mw) of BR is preferably 300,000 or more, more preferably 350,000 or more, and further preferably 400,000 or more. In addition, from the viewpoints of crosslinking uniformity, etc., it is preferably 2,000,000 or less, more preferably 1,000,000 or less. In addition, the Mw of BR is measured by the said measurement method.

[0091] From the viewpoint of the effects of the present invention, the content of BR in the rubber component is preferably 50 mass% or less, more preferably 40 mass% or less, further preferably 30 mass% or less, and particularly preferably 25 mass% or less. In addition, the lower limit value of this content is not particularly limited, and for example, it can be 1 mass% or more, 3 mass% or more, 5 mass% or more, 7 mass% or more, 10 mass% or more.

[0092] (SBR) There are no particular restrictions on the SBR, and examples thereof include unmodified solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and their modified SBR (modified S-SBR, modified E-SBR), etc. As the modified SBR, SBR modified at the terminal and / or main chain, modified SBR coupled with tin, silicon compounds, etc. (condensate, having a branched structure, etc.) can be cited. Further, hydrides of these SBR (hydrogenated SBR) can also be used. These SBRs can be used alone or in combination of two or more.

[0093] As the SBR related to the present embodiment, incremental SBR or non-incremental SBR can be used. When using incremental SBR, the increment amount of SBR, that is, the content of the incremental plasticizer contained in SBR, is preferably 10 to 50 parts by mass relative to 100 parts by mass of the rubber solid component of SBR.

[0094] The listed SBRs can be used alone or in combination of two or more. As the listed SBRs, commercially available ones such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., ZS Elastomer Co., Ltd. can be used.

[0095] The styrene content of SBR can be appropriately selected so that the total styrene amount S in the rubber component satisfies the range described later, but is preferably 40% by mass or less, more preferably 37% by mass or less, further preferably 34% by mass or less, and particularly preferably 30% by mass or less. In addition, the styrene content of SBR is preferably 5% by mass or more, more preferably 7% by mass or more, further preferably 10% by mass or more, and particularly preferably 12% by mass or more. In addition, the styrene content of SBR is measured by the above-mentioned measurement method.

[0096] From the viewpoints of ensuring reactivity with silica and abrasion resistance performance, the vinyl content of SBR is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more. In addition, from the viewpoints of tensile strength at break and abrasion resistance performance, the vinyl content of SBR is preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 35 mol% or less. In addition, in this specification, the vinyl content of SBR is measured by the above-mentioned measurement method.

[0097] From the viewpoint of the effect of the present invention, the weight-average molecular weight (Mw) of SBR is preferably 100,000 or more, more preferably 200,000 or more, and further preferably 300,000 or more. In addition, from the viewpoint of crosslinking uniformity, the weight-average molecular weight is preferably 2,000,000 or less, more preferably 1,800,000 or less, and further preferably 1,500,000 or less. In addition, the weight-average molecular weight of SBR is measured by the above-mentioned measurement method.

[0098] The SBR content in the rubber component can be appropriately selected so that the total styrene amount S in the rubber component satisfies the following range. Preferably, it is 20% by mass or more, more preferably 30% by mass or more, further preferably 40% by mass or more, still further preferably 50% by mass or more, and particularly preferably 60% by mass or more. On the other hand, the SBR content in the rubber component is preferably 99% by mass or less, more preferably 95% by mass or less, further preferably 90% by mass or less, and particularly preferably 85% by mass or less.

[0099] From the viewpoint of the effects of the present invention, the total styrene amount S in the rubber component is preferably 30% by mass or less, more preferably 27% by mass or less, further preferably 25% by mass or less, and particularly preferably 22% by mass or less. In addition, the lower limit value of the total styrene amount S in the rubber component is not particularly limited, and is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and particularly preferably 7% by mass or more.

[0100] (Other rubber components) Within the range not affecting the effects of the present invention, the rubber component may contain rubber components other than diene rubbers (non-diene rubbers). As the non-diene rubber, rubber components generally used in the tire industry can be used, such as butyl rubber, ethylene propylene rubber, poly(norbornene) rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), and alcohol (Hydrin) rubber. 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.

[0101] (Rubber components synthesized from recycled and biomass-derived raw materials) The monomers that are structural units of synthetic rubbers such as IR, BR, and SBR can be derived from underground resources such as petroleum and natural gas, or can be recovered from rubber products such as tires and non-rubber products such as polystyrene. As the monomers obtained by recycling (recycled monomers), there is no particular limitation, and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. As the butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the aromatic vinyl compound, there is no particular limitation, and examples include styrene. Among them, it is preferable to use recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and recycled styrene (recycled styrene) as raw materials.

[0102] The method for manufacturing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, the method for manufacturing the recycled naphtha is not particularly limited. For example, it can be decomposing rubber products such as tires under high temperature and high pressure, decomposing with microwaves, or performing extraction after mechanical pulverization.

[0103] Furthermore, the monomer that is a structural unit of synthetic rubbers such as IR, BR, and SBR can be a monomer derived from biomass. In this specification, biomass refers to substances from natural resources such as plants. There is no particular limitation on the biomass, and examples thereof include agricultural and forestry products, sugars, wood chips, plant residues after obtaining useful components, ethanol from plants, biomass naphtha, and the like.

[0104] The monomer derived from biomass (biomass monomer) is not particularly limited, and examples thereof include butadiene derived from biomass and aromatic vinyl compounds derived from biomass. As the butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the aromatic vinyl compound, there is no particular limitation, and styrene and the like can be mentioned. In addition, the method for manufacturing the biomass monomer is not particularly limited, and examples thereof include products based on biological and / or chemical and / or physical transformation of animals and plants. As the biological transformation, fermentation by microorganisms is representative. As the chemical and / or physical transformation, products based on catalysts, products based on high heat, products based on high pressure, products based on electromagnetic waves, products based on critical liquids, and combinations thereof can be mentioned.

[0105] The polymer synthesized from the biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from butadiene derived from biomass and aromatic vinyl / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl compounds derived from biomass. As the aromatic vinyl / butadiene copolymer, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be mentioned, for example.

[0106] Whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured based on ASTM D6866-10.

[0107] pMC refers to the 14 C concentration of the sample and the 14 C concentration of the modern standard reference, and it is a value used as an index indicating the biomass ratio of the compound. The meaning of this value is as described below.

[0108] One mole of carbon atoms (6.02×10 23 atoms) contains approximately one trillionth of the normal carbon atoms, i.e., about 6.02×10 11 atoms 14 of 14 14 The half-life of 14 14 14 14 14 14 14

[0109] On the other hand, 14 14 14 14 -12 14 13 13 12 14

[0110] This 14 13 13 12 14 14 12 14 14 14 13 ​​​​​​​​​​The C correction constant is used as a standard for implementing the attenuation correction value from 1950 AD to the measurement date. 14 The value of the C concentration (100%) is used. The ratio of this value to the value of the actually measured sample is the pMC value.

[0111] Therefore, if rubber is made of 100% biomass-derived materials, although there are regional differences, etc., many are not 100 under the current normal conditions, and 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. As described above, this value corresponds to a biomass ratio of 0%.

[0112] As described above, using materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, for the rubber composition is appropriate in terms of environmental protection.

[0113] <Filler> The rubber composition according to this embodiment contains a sustainable filler as a filler, and may also contain fillers other than the sustainable filler. As the sustainable filler, there is no particular limitation as long as it is a filler made from biomass materials or a filler obtained from used articles containing fillers, and sustainable silica and sustainable carbon black are preferred.

[0114] (Silica) Examples of the sustainable silica include silica made from biomass materials. Specifically, amorphous silica purified from rice husks can be cited.

[0115] Silica made from biomass materials can be obtained, for example, as follows: From the rice husk ash obtained by burning rice husks, the silicate is extracted with a sodium hydroxide solution, and this silicate is reacted with sulfuric acid in the same manner as conventional wet silica, and the resulting silica precipitate is filtered, washed with water, dried, and pulverized (for example, refer to Japanese Patent Laid-Open No. 2019-38728).

[0116] If silica crystallizes, it is insoluble in water and cannot be utilized as the silicic acid that is its component. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0117] The amorphous silica extracted from rice husks can use commercially available products from companies such as Wilmar.

[0118] From the viewpoint of ensuring reinforcement and tread wear resistance, the nitrogen adsorption specific surface area (N2SA) of the sustainable silica is preferably 110 m 2140 m / g or more, more preferably 170 m / g or more 2 170 m / g or more, further preferably 200 m / g or more 2 200 m / g or more, particularly preferably 250 m / g or more 2 250 m / g or more. In addition, from the viewpoints of heat generation property and processability, 350 m / g or less is preferable, more preferably 300 m / g or less 2 300 m / g or less, more preferably 250 m / g or less 2 250 m / g or less, further preferably 200 m / g or less 2 200 m / g or less. In addition, the N2SA of silica is measured by the above-described measurement method

[0119] From the viewpoints of increasing the specific surface area of silica, increasing the interaction with the rubber component, suppressing the movement of molecular chains, and suppressing heat generation, the average primary particle diameter of silica is preferably 20 nm or less, more preferably 18 nm or less, and further preferably 16 nm or less. The lower limit value of the average primary particle diameter is not particularly limited, but from the viewpoint of the dispersibility of silica, 1 nm or more is preferable, more preferably 3 nm or more, and further preferably 5 nm or more. In addition, the average primary particle diameter of silica is measured by the above-described measurement method

[0120] The silica using a biomass material as a raw material according to the present embodiment preferably contains silica having a primary particle diameter of 23 nm or more. It is considered that by containing silica having a primary particle diameter of 23 nm or more, the low fuel consumption performance can be improved. In addition, "containing silica having a primary particle diameter of 23 nm or more" in the present specification means that in the cumulative particle size in the volume-based particle size distribution of silica, 99% of the particle diameter (D99) is 23 nm or more

[0121] The silica other than the sustainable silica is not particularly limited. For example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), etc., and silica generally used in the tire industry can be used. Among them, hydrous silica prepared by a wet method is preferable because of the large number of silanol groups

[0122] From the viewpoints of ensuring the reinforcing property and the attenuation property of the tread portion, the nitrogen adsorption specific surface area (N2SA) of the silica other than the sustainable silica is preferably 110 m / g or more, more preferably 140 m / g or more 2 140 m / g or more, further preferably 170 m / g or more 2 170 m / g or more, particularly preferably 200 m / g or more 2 200 m / g or more, particularly preferably 250 m / g or more 2 250 m / g or more. In addition, from the viewpoints of heat generation property and processability, 350 m / g or less is preferable, more preferably 300 m / g or less 2 300 m / g or less, more preferably 250 m / g or less 2 250 m / g or less, further preferably 200 m / g or less 2 200 m / g or less

[0123] Based on the viewpoints of increasing the specific surface area of silica, increasing the interaction with the rubber component, suppressing the movement of molecular chains, and suppressing heat generation, the average primary particle diameter of silica other than sustainable silica is preferably 20 nm or less, more preferably 18 nm or less, and further preferably 16 nm or less. The lower limit value of the average primary particle diameter is not particularly limited, and based on the viewpoint of silica dispersibility, it is preferably 1 nm or more, more preferably 3 nm or more, and further preferably 5 nm or more.

[0124] Based on the viewpoints of the effects of the present invention, the content of sustainable silica relative to 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 35 parts by mass or more, further preferably 50 parts by mass or more, and particularly preferably 60 parts by mass or more. In addition, the content is preferably 140 parts by mass or less, more preferably 120 parts by mass or less, further preferably 100 parts by mass or less, and particularly preferably 95 parts by mass or less.

[0125] Based on the viewpoints of ensuring reinforcement and attenuation of the tread portion, the content of silica relative to 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 35 parts by mass or more, further preferably 50 parts by mass or more, and particularly preferably 60 parts by mass or more. In addition, based on the viewpoint of weight reduction for reducing the specific gravity of the rubber, it is preferably 140 parts by mass or less, more preferably 120 parts by mass or less, further preferably 100 parts by mass or less, and particularly preferably 95 parts by mass or less.

[0126] (Carbon black) Examples of sustainable carbon black include carbon black made from biomass materials such as lignin and vegetable oil, and recycled carbon black obtained by thermally decomposing and purifying carbon black-containing products such as tires.

[0127] In this specification, "recycled carbon black" refers to carbon black obtained by pulverizing used products such as tires containing carbon black and firing the pulverized material. According to the thermogravimetric measurement method based on JIS K 6226-2:2003, when it is oxidized and burned by heating in air, the proportion of the mass of the non-combustible component, that is, the ash content, is 13% by mass or more. That is, the proportion of the mass (carbon content) of the reduced amount caused by the oxidation combustion of the recycled carbon black is 87% by mass or less. Recycled carbon black can also be represented by rCB.

[0128] Recycled carbon black can be obtained from the thermal decomposition process of used pneumatic tires. For example, as mentioned in the specification of European Patent Application Publication No. 3427975, in "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408 - 449 (2012), especially pages 438, 440, and 442, it is described that carbon black is obtained by thermal decomposition of organic materials at 550 - 800 °C with oxygen excluded, or vacuum thermal decomposition at a lower temperature (

[0027] ). The carbon black obtained by such a thermal decomposition process, as mentioned in

[0004] of Patent No. 6856781, usually lacks functional groups on its surface (Comparison of the surface morphology and chemistry of thermal decomposition carbon black and commercially available carbon black, Powder Technology 160 (2005) 190 - 193).

[0129] The surface of recycled carbon black may lack functional groups, or it can also be treated so that its surface contains functional groups. The treatment in such a way that the surface of recycled carbon black contains functional groups can be carried out by ordinary methods. For example, in the specification of European Patent Application Publication No. 3173251, carbon black obtained from the thermal decomposition process is treated with potassium permanganate under acidic conditions, thereby obtaining carbon black with hydroxyl groups and / or carboxyl groups on its surface. In addition, in the bulletin of Patent No. 6856781, carbon black obtained from the thermal decomposition process is treated with an amino acid compound containing at least one mercapto group or disulfide group to obtain surface-activated carbon black. The recycled carbon black involved in this embodiment includes carbon black treated so that its surface contains functional groups.

[0130] Commercially available products such as those from Strable Green Carbon Company and LDCarbon Company can be used as recycled carbon black.

[0131] The recycled carbon black involved in this embodiment preferably contains carbon black with a primary particle size of 25 nm or more. It is considered that by containing carbon black with a primary particle size of 25 nm or more, the low fuel consumption performance can be improved. In addition, in this specification, "containing carbon black with a primary particle size of 25 nm or more" means that based on the cumulative particle size in the volume-based particle size distribution of carbon black, 99% of the particle size (D99) is 25 nm or more.

[0132] As carbon black other than sustainable carbon black, there is no particular limitation, and generally used products in the tire industry such as GPF, FEF, HAF, ISAF, SAF, etc. can be used.

[0133] From the viewpoints of weather resistance and reinforcement, the nitrogen adsorption specific surface area (N2SA) of carbon black other than sustainable carbon black is preferably 50 m 2 / g or more, more preferably 80 m 2 / g or more, and further preferably 100 m 2In addition, from the perspectives of dispersibility, low fuel consumption, destructive properties, and durability, 250 m / g or more is preferred. 2 / g or less, more preferably 220m 2 / g or less. In addition, the carbon black N2SA is measured by the above-mentioned measurement method.

[0134] From the viewpoint of the effects of the present invention, the content of sustainable carbon black relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more. In addition, the content is preferably 50 parts by mass or less, more preferably 35 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

[0135] From the viewpoint of weather resistance and reinforcement, the carbon black content relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more. In addition, from the viewpoint of low fuel consumption performance, it is preferably 50 parts by mass or less, more preferably 35 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

[0136] (Other fillers) Fillers other than silica and carbon black are not particularly limited, and include, for example, aluminum hydroxide, aluminum oxide (alumina), calcium carbonate, magnesium sulfate, talc, clay, biochar, etc., and products commonly used in the tire industry can be mixed. These other fillers can be used alone or in combination of two or more.

[0137] From the perspective of environmental load, the ratio of the total content of sustainable fillers to the total content of fillers is preferably 0.40 or more, more preferably 0.50 or more, further preferably 0.60 or more, and particularly preferably 0.70 or more. On the other hand, the upper limit of the ratio of the total content of sustainable fillers to the total content of fillers is not particularly limited.

[0138] The ratio of the carbon black content to the silica content is preferably 0.50 or less, more preferably 0.40 or less, further preferably 0.30 or less, further preferably 0.20 or less, and particularly preferably 0.15 or less. By making the ratio of the carbon black content to the silica content within the above range, the low fuel consumption performance can be further improved. On the other hand, the lower limit of the ratio of the carbon black content to the silica content is not particularly limited, and can be, for example, 0.01 or more, 0.02 or more, 0.05 or more, or a filler containing no carbon black.

[0139] From the viewpoint of ensuring reinforcement and attenuation of the tread portion, the total content F of the filler relative to 100 parts by mass of the rubber component is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, further preferably 60 parts by mass or more, further preferably 65 parts by mass or more, further preferably 70 parts by mass or more, and particularly preferably 75 parts by mass or more. From the viewpoint of the effects of the present invention, it is preferably 140 parts by mass or less, more preferably 120 parts by mass or less, further preferably 100 parts by mass or less, and particularly preferably 95 parts by mass or less.

[0140] (Silane coupling agent) Silica is preferably used in combination with a silane coupling agent. There is no particular limitation on the silane coupling agent, and in the tire industry, any silane coupling agent that has been conventionally used in combination with silica can be used. From the aspect of better obtaining the desired effects, it is preferably one or more silane coupling agents selected from the group consisting of sulfide-based silane coupling agents and mercapto-based silane coupling agents, and more preferably mercapto-based silane coupling agents.

[0141] Examples of the sulfide-based silane coupling agent include bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide, and the like. These sulfide-based silane coupling agents can be used alone or in combination of two or more.

[0142] In the present specification, the mercapto-based silane coupling agent refers to a silane coupling agent having a mercapto group and a silane coupling agent having a structure in which the mercapto group is protected by a protecting group. There is no particular limitation on the mercapto-based silane coupling agent, and examples thereof include a compound having a mercapto group represented by the following formula (2), a compound in which the mercapto group is protected by an ester represented by the following formula (3), and a compound containing a bonding unit A represented by the following formula (4) and / or a bonding unit B represented by the following formula (5). Among them, based on the reason that the effects of the present invention can be better exerted, a compound represented by the following formula (3), or a compound containing a bonding unit A represented by the following formula (4) and / or a bonding unit B represented by the following formula (5) is preferred, and a compound represented by the following formula (3) is more preferred. These mercapto-based silane coupling agents can be used alone or in combination of two or more.

Chemical formula 1

Chemical formula 2

Chemical formula 3

Chemical formula 4

[0143] Examples of the compound represented by the formula (2) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, the compound represented by the following formula (6) (Si363 manufactured by Evonik Degussa GmbH), etc. The compound represented by the following formula (6) can be appropriately used. They can be used alone or in combination of two or more. [Chemical 5]

[0144] Examples of the compound represented by the formula (3) include 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, 3-octanoylthio-1-propyltrimethoxysilane, etc.

[0145] It is considered that the compound containing the bonding unit A represented by the formula (4) and / or the bonding unit B represented by the formula (5) suppresses the increase in viscosity during processing compared with a sulfur-based silane coupling agent such as bis-(3-triethoxysilylpropyl)tetrasulfide. Therefore, the dispersibility of silica is better, and the low fuel consumption performance, wet grip performance, and tensile strength at break are further improved. It is considered that this is because the sulfur part of the bonding unit A is a C-S-C bond, which is thermally stable compared with tetrasulfide and disulfide, and thus the increase in Mooney viscosity is small.

[0146] From the viewpoint of suppressing the increase in viscosity during processing, the content of the bonding unit A is preferably 30 to 99 mol%, more preferably 50 to 90 mol%. In addition, the content of the bonding unit B is preferably 1 to 70 mol%, more preferably 5 to 65 mol%, and further preferably 10 to 55 mol%. In addition, the total content of the bonding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. In addition, the contents of the bonding units A and B also include the amounts when the bonding units A and B are located at the ends of the silane coupling agent. The form when the bonding units A and B are located at the ends of the silane coupling agent is not particularly limited, and a unit corresponding to the formulas (4) and (5) representing the bonding units A and B can be formed.

[0147] In the compound containing the binding unit A represented by the formula (4) and the binding unit B represented by the formula (5), the total number of repetitions (x + y) of the number of repetitions (x) of the binding unit A and the number of repetitions (y) of the binding unit B is preferably in the range of 3 to 300. If within this range, due to -C7H of the binding unit A 15 The mercapto silane covering the binding unit B can inhibit the shortening of the coking time and ensure good reactivity with silica and rubber components.

[0148] Examples of the compound containing the binding unit A represented by the formula (4) and / or the binding unit B represented by the formula (5) include NXT-Z30, NXT-Z45, NXT-Z60, NXT-Z100, etc. manufactured by Momentive. These can be used alone or in combination of two or more.

[0149] There is no particular limitation on the silane coupling agent other than the sulfide-based silane coupling agent and the mercapto-based silane coupling agent. Examples include 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; glycidoxy-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. These other silane coupling agents can be used alone or in combination of two or more. As the listed silane coupling agents, for example, those manufactured and sold by Momentive, Evonik Degussa, etc. can be used.

[0150] From the viewpoint of improving the dispersibility of silica, the content of the silane coupling agent relative to 100 parts by mass of silica is preferably 1.0 part by mass or more, more preferably 3.0 part by mass or more, and further preferably 5.0 part by mass or more. In addition, from the viewpoints of cost and processability, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 12 parts by mass or less.

[0151] <Other Blending Agents> The rubber composition according to the present embodiment may appropriately contain blending agents generally used in the tire industry in the past, such as plasticizers, vulcanized rubber particles, processing aids, waxes, anti-aging agents, stearic acid, zinc oxide, vulcanizing agents, vulcanization accelerators, etc., in addition to the above components.

[0152] A plasticizer refers to a material that imparts plasticity to rubber components, and is a concept that includes both plasticizers that are liquids at 25°C and plasticizers that are solids at normal temperature (25°C). Examples of plasticizers include resin components, oils, liquid rubbers, ester-based plasticizers, etc. These plasticizers can be from mineral resources such as petroleum and natural gas, or from biomass, or from naphtha recovered from rubber products and non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by thermally decomposing and extracting products containing used tires and various components can also be used as plasticizers. These plasticizers can be used alone or in combination of two or more.

[0153] (Resin component) As the resin component, there is no particular limitation as long as it is a resin component commonly used in the tire industry. Examples include tackifying resins such as dicyclopentadiene-based resins, aromatic vinyl resins, C9-based resins, C5-based resins, C5C9-based resins, terpene-based resins, rosin-based resins, and phenol-based resins. These resin components can be used alone or in combination of two or more.

[0154] "Dicyclopentadiene-based resin" refers to a resin containing cyclopentadiene (CPD) or dicyclopentadiene (DCPD) as a monomer component, and can also be its hydride or modified product. Examples of dicyclopentadiene-based resins include DCPD / C9 resins containing dicyclopentadiene and the C9 fraction described below as monomer components (this DCPD / C9 resin can also be its hydride obtained by hydrogenation or its modified product obtained by modification), and preferably DCPD / C9 resins containing dicyclopentadiene and styrene as monomer components. As dicyclopentadiene-based resins, for example, products commercially available from ExxonMobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. can be used. These dicyclopentadiene-based resins can be used alone or in combination of two or more.

[0155] "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 can also be its hydride obtained by hydrogenation or its modified product obtained by modification. As aromatic vinyl-based resins, for reasons of economy, ease of 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, those commercially available from CLAYTON Company, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used. These aromatic vinyl-based resins can be used alone or in combination of two or more.

[0156] "C9 resin" refers to a resin obtained by polymerizing C9 fraction, which can be a resin obtained by homopolymerizing C9 fraction or a copolymer of C9 fraction and other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) and C9 fraction is called DCPD / C9 resin. In addition, it can also be a hydride obtained by hydrogenating it or a modified product obtained by modifying it. Examples of C9 fraction include petroleum fractions equivalent to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene. These C9 resins can be used alone or in combination of two or more.

[0157] "C5 resin" refers to a resin obtained by polymerizing C5 fraction, which can also be a hydride obtained by hydrogenating it or a modified product obtained by modifying it. Examples of C5 fraction include petroleum fractions equivalent to 4 to 5 carbon atoms such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene. These C5 resins can be used alone or in combination of two or more.

[0158] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, which can also be a hydride obtained by hydrogenating it or a modified product obtained by modifying it. As C5C9 petroleum resin, commercially available products such as those from Tosoh Corporation and LUHUA Company can be used. These C5C9 resins can be used alone or in combination of two or more.

[0159] "Terpene resin" refers to a resin containing terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as the monomer component with the highest content, which can also be a hydride obtained by hydrogenating it or a modified product obtained by modifying it. Specific examples of terpene resin include polyterpene resin containing only one or more of the above terpene compounds as monomer components; aromatic modified terpene resin containing the terpene compound and an aromatic compound as monomer components; terpene phenol resin containing the terpene compound and a phenolic compound as monomer components, etc. Examples of aromatic compounds as monomer components of aromatic modified terpene resin include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds as monomer components of terpene phenol resin include phenol, bisphenol A, cresol, and xylenol. These terpene resins can be used alone or in combination of two or more.

[0160] "Rosin-based resin" refers to a resin containing rosin acid compounds such as rosin acid, neoabietic acid, palustric acid, and isopimaric acid, or a hydride obtained by hydrogenating it or a modified product obtained by modifying it. As the rosin-based resin, there is no particular limitation, and examples thereof include natural resin rosin, rosin-modified resins obtained by modifying it such as hydrogenation, disproportionation, dimerization, and esterification. These rosin-based resins can be used alone or in combination of two or more.

[0161] "Phenol-based resin" refers to a resin containing phenol compounds such as phenol and cresol as the monomer component with the highest content. As the phenol-based resin, there is no particular limitation, and examples thereof include phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, and oil-modified phenol formaldehyde resin. These phenol-based resins can be used alone or in combination of two or more.

[0162] From the viewpoint of grip performance, the softening point of the resin component is preferably 60 °C or higher, more preferably 70 °C or higher, and further preferably 80 °C or higher. In addition, from the viewpoints of processability and improvement of 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 component is measured by the above-mentioned measurement method.

[0163] When containing a resin component, the content of the resin component relative to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more. In addition, from the viewpoint of suppressing heat generation, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, further preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

[0164] (Oil) Examples of the oil include mineral oil, vegetable oil, and animal oil. In addition, from the viewpoint of life cycle assessment, waste oil used in a rubber mixer or an engine and waste cooking oil used in a restaurant can be purified and used.

[0165] In this specification, mineral oil refers to oil from mineral resources such as petroleum and natural gas. Examples of the mineral oil include paraffin-based oil (mineral oil), naphthenic oil, and aromatic oil. Specific examples of the mineral oil include, for example, MES (mild extraction solvate), DAE (distilled aromatic extract), TDAE (treated distilled aromatic extract), TRAE (treated residual aromatic extract), and RAE (residual aromatic extract). In addition, under environmental countermeasures, oil with a low content of polycyclic aromatic compounds (PCA) can be used. Examples of the low-PCA-content oil include MES, TDAE, and heavy naphthenic oil.

[0166] In this specification, "vegetable oil" refers to, for example, 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 the vegetable oil, there may be mentioned 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, and waste cooking oils recovered from oils used as edible oils, etc. In addition, the vegetable oil may be liquid or solid at normal temperature (25°C). These vegetable oils may be used alone or in combination of two or more kinds.

[0167] 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 carried by glycerol is ester-bonded to a fatty acid. As the acylglycerol, there is no particular limitation, and it may be any one of 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, and triacylglycerol. Further, the acylglycerol may be a monomer, a dimer, or a polymer of three or more units. In addition, acylglycerols of two or more units can be obtained by thermal polymerization, oxidative polymerization, etc. In addition, the acylglycerol may be liquid or solid at normal temperature (25°C).

[0168] As a method for confirming the presence of the acylglycerol in the rubber composition, there is no particular limitation. For example, it can be confirmed by the following 1 1H-NMR measurement. Specifically, the rubber composition containing mixed triacylglycerol is immersed in deuterated chloroform at normal temperature (25°C) for 24 hours. After removing the rubber composition, 1H-NMR measurement is carried out at room temperature. 1 When the signal of tetramethylsilane (TMS) is 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed, and it is presumed that these signals are signals from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. In addition, the "around" in this paragraph means a range of ±0.10 ppm.

[0169] The fatty acid has no particular limitation and may be an unsaturated fatty acid or a saturated fatty acid. As the unsaturated fatty acid, there may be mentioned monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. In addition, as the saturated fatty acid, there may be mentioned butyric acid, lauric acid, etc.

[0170] Among them, as the fatty acid, it is desirable to contain a fatty acid with few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, preferably oleic acid. As the vegetable oil containing such a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid can be used, or a modified vegetable oil such as a transesterified vegetable oil can also be used. In addition, in order to produce a vegetable oil containing such a fatty acid, plants can be improved by variety improvement, genetic recombination, etc.

[0171] As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Olisoy Co., H&R Co., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0172] Examples of the animal oil include fish oil, beef tallow, or an oil alcohol derived therefrom.

[0173] From the viewpoint of processability, the oil content (total combined amount when multiple oils are used in combination) relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, still further preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more. In addition, from the viewpoint of improving abrasion resistance performance, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, further preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0174] The liquid rubber is not particularly limited as long as it is a polymer in a liquid state at normal temperature (25°C). Examples include liquid butadiene rubber (liquid BR), liquid styrene-butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene-isoprene rubber (liquid SIR), liquid farnesene rubber, etc. These liquid rubbers can be used alone or in combination of two or more.

[0175] 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), di(undecyl) 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), tris(xylene) phosphate (TXP), etc. These ester plasticizers can be used alone or in combination of two or more.

[0176] The content of the plasticizer relative to 100 parts by mass of the rubber component (the total combined amount when multiple plasticizers are used) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 35 parts by mass or more. In addition, the content is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, further preferably 60 parts by mass or less, and particularly preferably 50 parts by mass or less.

[0177] The vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder specified in JIS K 6316:2017 can be used, etc. From the viewpoints of environmental consideration and cost, recycled rubber powder made from crushed waste tires, etc. is preferred. These can be used alone or in combination of two or more.

[0178] There is no particular limitation on the vulcanized rubber particles, which can be unmodified vulcanized rubber particles or modified vulcanized rubber particles. As commercially available products of vulcanized rubber, products of, for example, Lehigh Company, Murakami Rubber Industry Co., Ltd. can be used.

[0179] When the vulcanized rubber particles are contained, the content of the vulcanized rubber particles relative to 100 parts by mass of the rubber component can be appropriately adjusted, for example, in the range of more than 1 part by mass and less than 80 parts by mass.

[0180] Examples of the processing aids include 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. As the processing aids, products commercially available from companies such as Schill+Seilacher Company, Performance Additives can be used. These processing aids can be used alone or in combination of two or more.

[0181] When the processing aids are contained, the content relative to 100 parts by mass of the rubber component, from the viewpoint of exerting the improvement effect of processability, 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.

[0182] As the wax, there is no particular limitation, and any one commonly used in the tire industry can be appropriately used. Examples include mineral waxes, waxes derived from plants, etc. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Waxes derived from plants refer to waxes derived from natural resources such as plants. Among them, mineral waxes are preferred. Examples of waxes derived from plants include rice wax, carnauba wax, candelilla wax, etc. Examples of mineral waxes include paraffin wax, microcrystalline wax, their selected special waxes, etc., and paraffin wax is preferred. In addition, the wax involved in this embodiment does not contain stearic acid. The wax can be a commercially available product from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., PARAMELT Corporation, etc. These waxes can be used alone or in combination of two or more.

[0183] From the perspective of the weather resistance of rubber, the content of the wax when containing wax is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.5 part by mass or more, based on 100 parts by mass of the rubber component. In addition, from the perspective of preventing the whitening of the tire caused by blooming, it is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less.

[0184] There is no particular limitation on the antioxidant, and examples include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylxyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD), etc.; quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; bisphenol, triphenol, polyphenol-based antioxidants such as tetrakis[methylene-3-(3',5'-di-t-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 2,2,4-trimethyl-1,2-dihydroquinoline polymer are more preferred. As commercially available products, products from, for example, Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Corporation, etc. can be used. These antioxidants can be used alone or in combination of two or more.

[0185] From the viewpoint of ozone crack resistance of rubber, the content of the anti-aging agent relative to 100 parts by mass of the rubber component when the anti-aging agent is contained is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.5 part by mass or more. In addition, from the viewpoints of abrasion resistance and wet grip performance, it is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less.

[0186] From the viewpoint of processability, the content of stearic acid relative to 100 parts by mass of the rubber component when stearic acid is contained is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.5 part by mass or more. In addition, from the viewpoint of vulcanization rate, it is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less.

[0187] From the viewpoint of processability, the content of zinc oxide relative to 100 parts by mass of the rubber component when zinc oxide is contained is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.5 part by mass or more. In addition, from the viewpoint of abrasion resistance, it is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less.

[0188] As the vulcanizing agent, sulfur is preferably used. As sulfur, powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, etc. can be used.

[0189] From the viewpoint of ensuring sufficient vulcanization reaction, the content of sulfur relative to 100 parts by mass of the rubber component when sulfur is contained as the vulcanizing agent is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and further preferably 1.0 part by mass or more. In addition, from the viewpoint of deterioration prevention, it is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and further preferably 3.5 parts by mass or less. In addition, when using oil-containing sulfur as the vulcanizing agent, the content of the vulcanizing agent is the total content of the pure sulfur component contained in the oil-containing sulfur.

[0190] Examples of vulcanizing agents other than sulfur include alkylphenol / sulfur chloride condensate, 1,6-hexamethylene-dithiocarbamate disodium salt dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyl disulfide) hexane, etc. These vulcanizing agents other than sulfur can be commercially available from companies such as Taoka Chemical Industry Co., Ltd., Lanxess Co., Ltd., and Flexis Co., Ltd.

[0191] As vulcanization accelerators, examples include sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiuram-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, caprolactam disulfide, and the like. These vulcanization accelerators can be used alone or in combination of two or more. Among them, from the viewpoint of better obtaining the desired effects, one or more vulcanization accelerators selected from the group consisting of sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, and guanidine-based vulcanization accelerators are preferred, and it is more preferred to use a sulfenamide-based vulcanization accelerator and a guanidine-based vulcanization accelerator in combination.

[0192] As sulfenamide-based vulcanization accelerators, examples include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like. Among them, TBBS and CBS are preferred.

[0193] As thiazole-based vulcanization accelerators, examples include 2-mercaptobenzothiazole (MBT) or its salts, bis-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, and the like. Among them, MBTS and MBT are preferred, and MBTS is more preferred.

[0194] As guanidine-based vulcanization accelerators, examples include 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of di-catechol borate, 1,3-di-o-isopropylphenylguanidine, 1,3-di-o-phenylguanidine, 1,3-di-o-isopropylphenyl-2-propionylguanidine, and the like. Among them, DPG is preferred.

[0195] When a vulcanization accelerator is contained, the content of the vulcanization accelerator relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more. In addition, the content of the vulcanization accelerator relative to 100 parts by mass of the rubber component is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, and still more preferably 4.0 parts by mass or less. By making the content of the vulcanization accelerator within the above range, it tends to ensure the breaking strength and elongation.

[0196] In this specification, various carbon-containing materials (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining these various materials from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process for converting carbon dioxide into methane can be used.

[0197] [Rubber Composition and Tire Manufacturing] The rubber composition according to this embodiment can be manufactured by a known method. For example, it can be manufactured by kneading the respective components with a rubber kneading device such as an open extruder or a closed kneader (Banbury mixer, extruder, etc.).

[0198] The kneading process includes, for example: a basic kneading process of kneading the mixing agents and additives other than the vulcanizing agent and the vulcanization accelerator; and a final kneading (F kneading) process of adding the vulcanizing agent and the vulcanization accelerator to the kneaded product obtained in the basic kneading process and kneading. Further, the basic kneading process can be divided into multiple processes as desired.

[0199] There are no particular restrictions on the kneading conditions. For example, in the basic kneading process, kneading is carried out at a discharge temperature of 150 to 170°C for 3 to 10 minutes, and in the final kneading process, kneading is carried out at 70 to 110°C for 1 to 5 minutes. There are no particular restrictions on the vulcanization conditions. For example, a method of vulcanizing at 150 to 200°C for 10 to 30 minutes can be cited.

[0200] A tire having a tread portion made of the rubber composition can be manufactured by a conventional method. That is, an unvulcanized rubber composition obtained by mixing the above-mentioned respective components with the rubber component as needed is extruded according to the shape of the first layer of the tread portion, and is bonded together with the inner rubber layer of the tread portion and other tire components on a tire molding machine, and is molded by a conventional method to form an unvulcanized tire. By heating and pressurizing this unvulcanized tire in a vulcanizer, a tire can be manufactured. There are no particular restrictions on the vulcanization conditions. For example, a method of vulcanizing at 150 to 200°C for 10 to 30 minutes can be cited.

[0201] [Use of the tire] The tire according to this embodiment can be suitably used for passenger car tires, truck / bus tires, two-wheeler tires, and racing tires, and is preferably used for passenger car tires. In addition, a passenger car tire means a tire premised on being installed on a four-wheeled vehicle, and its maximum load capacity is 1000 kg or less. [Examples]

[0202] The following shows examples (examples) considered to be preferable when implementing, and the scope of the present invention is not limited by the examples. Using the various drugs shown below, a tire having the first layer of the tread portion obtained by mixing according to Tables 1 and 2 was investigated, and the results calculated based on the following evaluation methods are shown in Tables 1 and 2.

[0203] The following shows the various drugs used in the examples and comparative examples in a concentrated manner. NR: TSR20 SBR1: EUROPRENE® SOL R C2525 manufactured by Versalis (styrene content: 26% by mass, vinyl content: 24% by mass, Mw: 600,000, non-extended product) SBR2: T3830 manufactured by Asahi Kasei Corporation (styrene content: 33% by mass, vinyl content: 34% by mass, Mw: 950,000, non-oil extended product) BR: CB24 manufactured by Lanxess AG (BR synthesized using an Nd-based catalyst, cis content: 96 mol%, Mw: 500,000) Carbon black: Show Black N220 manufactured by Cabot Japan Ltd. (N2SA: 111 m 2 / g) Silica: ULTRASIL® VN3 manufactured by Evonik Degussa GmbH (N2SA: 175 m 2 / g, average primary particle size: 17 nm) Sustainable filler 1: SS550 manufactured by Streble Green Carbon (carbon black obtained from the thermal decomposition process of tires) Sustainable filler 2: Silica derived from rice husks obtained through the following production example (N2SA: 175 m 2 / g, average primary particle size: 18 nm) Sustainable filler 3: Silica derived from rice husks obtained through the following production example (N2SA: 235 m 2 / g, average primary particle size: 15 nm) Silane coupling agent 1: Si266 manufactured by Evonik Degussa GmbH (bis(3-triethoxysilylpropyl) disulfide) Silane coupling agent 2: NXT-Z45 manufactured by Momentive Performance Materials Inc. (mercapto-based silane coupling agent, copolymer of bonding unit A and bonding unit B (bonding unit A: 55 mol%, bonding unit B: 45 mol%)) Oil: VivaTec 500 manufactured by H&R (TDAE oil) Resin component: Oppera PR395 manufactured by ExxonMobil Chemical Company (hydrogenated DCPD / C9 resin, softening point: 118 °C) Wax: OzoAce 0355 of Nippon Seiro Co., Ltd. (paraffin wax) Antioxidant: Nocrack 6C manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) Zinc oxide: Zinc White No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Stearic acid "Tsubaki" manufactured by Yushu Co., Ltd. Sulfur: HK-200-5 (powdered sulfur containing 5% oil) manufactured by Hosoi Chemical Industry Co., Ltd. Accelerator: Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0204] (Manufacturing examples of sustainable fillers 2 and 3) Add rice husk ash to an aqueous sodium hydroxide solution, and heat and stir with a stirring rod. Then, restore to room temperature, centrifuge to precipitate the carbon component, and filter the supernatant with a Kiriyama funnel. Further, after adding water to the precipitate and stirring, centrifuge again, filter the supernatant with a Kiriyama funnel, and mix this filtrate with the previous filtrate. Then, dilute the mixed filtrate with water to obtain an aqueous sodium silicate solution.

[0205] Take out a part of the aqueous sodium silicate solution, dilute it with pure water, then add 1 mol / L sulfuric acid to adjust the pH to 2 - 4, and then heat. Then, add the remaining part of the aqueous sodium silicate solution here to adjust the pH to 8 - 10, heat further, and dilute it with pure water to obtain a seed solution.

[0206] Heat and stir the seed solution. Here, while simultaneously dripping the remaining aqueous sodium silicate solution and 1 mol / L sulfuric acid to adjust the pH to the range of 8 - 11 and stirring. After the dripping of the aqueous sodium silicate solution is completed, continue to drip only 1 mol / L sulfuric acid at the same speed until the dripping is completed at the specified pH (1.5 - 6). Filter the white precipitate generated after the dripping is completed with a Kiriyama funnel, and wash the filtered product with water. Repeat these once again, dry the filtered product, and obtain sustainable filler 2.

[0207] In addition, by adjusting the amount of 1 mol / L sulfuric acid dripped into the seed solution and changing the pH value after the dripping is completed, sustainable filler 3 is obtained.

[0208] (Examples and Comparative Examples) According to the mixing formulas shown in Table 1 and Table 2, use a 1.7L closed Banbury mixer to knead the chemicals other than sulfur and the accelerator for 1 - 10 minutes before reaching the discharge temperature of 150 - 160°C to obtain a kneaded product. Next, use a two-roll open extruder to add sulfur and the accelerator to the kneaded product and knead for 4 minutes until reaching 105°C to obtain an unvulcanized rubber composition. Using this unvulcanized rubber composition, extrude and form it in an extruder equipped with a nozzle of a specified shape according to the shape of the first layer of the tread surface (thickness: 5 mm), and bond it together with the second layer of the tread surface (thickness: 2 mm) and other tire components to produce an unvulcanized tire, and obtain each test tire described in Table 1 and Table 2 by press vulcanization at 170°C for 12 minutes.

[0209] <Measurement of tanδ at 30°C and E* at 30°C> Regarding each vulcanized rubber test piece made by cutting out a piece with a length of 20 mm × width of 4 mm × thickness of 1 mm from the inside of the first layer of 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, the loss tangent tanδ and the complex elastic modulus E* were measured using a dynamic viscoelasticity measuring device (EPLEXOR series manufactured by GABO) under the conditions of a temperature of 30°C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and a tensile mode.

[0210] <Tensile Test> Regarding the dumbbell-shaped No. 7 test pieces cut out with a thickness of 1 mm from the inside of the first and second layers of the tread surface of each test tire, with the circumferential direction of the tire as the tensile direction and the radial direction of the tire as the thickness direction, a tensile test was carried out based on JIS K 6251:2017 in an atmosphere of 23°C at a tensile speed of 3.3 mm / second, and the modulus (M 200 )(MPa) at 200% elongation was measured.

[0211] <Low Fuel Consumption Performance> Using a rolling resistance test machine, the rolling resistance when each test tire was driven at an internal pressure of (230 kPa), a load of (3.43 kN), and a speed of (80 km / h) was measured and expressed as an index with the reference comparative example (Comparative Example 1 in Table 1, Comparative Example 5 in Table 2) being 100. The larger the index, the smaller the rolling resistance and the more excellent the low fuel consumption performance.

[0212] <Abrasion Resistance Performance> Each test tire was installed on a domestic FF vehicle, the groove depth of the tread surface after driving a distance of 8000 km was measured, and the driving distance when the tire groove depth decreased by 1 mm was calculated and expressed as an index with the reference comparative example (Comparative Example 1 in Table 1, Comparative Example 5 in Table 2) being 100. The larger the index, the more excellent the abrasion resistance performance.

[0213] <Comprehensive Performance> The sum of the above low fuel consumption index and abrasion resistance performance index was expressed as the comprehensive performance index.

[0214]

Table 1

[0215]

Table 2

[0216] <Embodiment> Examples of the embodiments of the present invention are shown below.

[0217] 〔1〕A tire having a tread portion with at least one rubber layer, wherein the ratio (G / W L ) of the tire weight G (kg) to the maximum load capacity W L (kg) of the tire is 0.0170 or less, the first layer constituting the tread is composed of a rubber composition containing a rubber component and a filler, the filler contains a sustainable filler, and when the grounding ratio on the grounding surface of the tread portion is R and the total content of the filler relative to 100 parts by mass of the rubber component in the rubber composition is F (parts by mass), the product (R×F) of R and F is greater than 42.0 (preferably greater than 44.0, more preferably greater than 46.0, and less than 75.0). 〔2〕The tire according to the above 〔1〕, wherein the sustainable filler contains silica made from biomass materials. 〔3〕The tire according to the above 〔1〕 or 〔2〕, wherein the sustainable filler contains recycled carbon black. 〔4〕The tire according to any one of the above 〔1〕 to 〔3〕, wherein G / W L is 0.0135 or less. 〔5〕The tire according to any one of the above 〔1〕 to 〔4〕, wherein the 30°C tanδ of the rubber composition is 0.20 or less. 〔6〕The tire according to any one of the above 〔1〕 to 〔5〕, wherein (R×F) / (G / W L ) is greater than 3000. 〔7〕The tire according to any one of the above 〔1〕 to 〔6〕, when the complex elastic modulus of the rubber composition at 30°C is 30°C E* (MPa), the product (R×30°C E*) of R and 30°C E* is greater than 2.5. 〔8〕The tire according to any one of the above 〔1〕 to 〔7〕, wherein the total styrene amount S in the rubber component is 25% by mass or less. 〔9〕The tire according to the above 〔8〕, wherein R×S is 15.0 or less. 〔10〕The tire according to the above 〔8〕 or 〔9〕, when the complex elastic modulus of the rubber composition at 30°C is 30°C E* (MPa), S / 30°C E* is 6.0 or less (preferably 5.5 or less, more preferably 0.3 or more and 5.0 or less). 〔11〕The tire according to any one of the above 〔1〕 to 〔10〕, wherein the rubber component contains an isoprene-based rubber. 〔12〕The tire according to any one of the above 〔1〕 to 〔11〕, wherein the rubber component contains a styrene-butadiene rubber having a styrene content of 30% by mass or less. 〔13〕The tire according to any one of the above 〔1〕 to 〔12〕, wherein when the modulus at 200% elongation of the rubber composition is M 200 (MPa), M 200 of the rubber composition, E* at 30°C, and tanδ at 30°C satisfy the following formula (1). M 200 × E* / tanδ at 30°C ≥ 100 ··· (1).

Claims

1. A tire, characterized in that: A tire having a tread portion having at least one rubber layer, Tire weight G and tire maximum load capacity W L The ratio is G / W L is below 0.0170, The first layer constituting the tread is composed of a rubber composition containing a rubber component and a filler. The filler contains sustainable filler, When the ground contact ratio of the ground contact surface of the tread portion is R and the total content of the filler in the rubber composition relative to 100 parts by mass of the rubber component is F, the product of R and F (R×F) is greater than 42.0, The tire weight G and the maximum load capacity W of the tire L The unit is kg, The unit of the total content of the filler is part by mass.

2. The tire according to claim 1, wherein the sustainable filler comprises silica made from biomass materials.

3. The tire according to claim 1, wherein the sustainable filler comprises recycled carbon black.

4. The tire according to any one of claims 1 to 3, wherein G / W L It is less than 0.0135. 5 . The tire according to claim 1 , wherein R×F is less than 75.

0. 6 . The tire according to claim 1 , wherein the rubber composition has a tan δ at 30° C. of 0.20 or less.

7. The tire according to any one of claims 1 to 3, wherein (R×F) / (G / W L ) is greater than 3000.

8. The tire according to any one of claims 1 to 3, wherein when the complex elastic modulus of the rubber composition at 30°C is 30°CE*, the product of R and 30°CE* (R x 30°CE*) is greater than 2.0, and the unit of 30°CE* is MPa. 9 . The tire according to claim 1 , wherein R×30° C. E* is greater than 2.

5.

10. The tire according to claim 8, wherein R×30°C E* is less than 8.

0. 11 . The tire according to claim 1 , wherein a total styrene amount S in the rubber component is 25% by mass or less. 12 . The tire according to claim 11 , wherein R×S is 15.0 or less. 13 . The tire according to claim 11 , wherein when the complex elastic modulus of the rubber composition at 30° C. is 30° C. E*, S / 30° C. E* is 6.0 or less, and the unit of 30° C. E* is MPa. 14 . The tire according to claim 1 , wherein the rubber component contains isoprene-based rubber. 15 . The tire according to claim 1 , wherein the rubber component contains styrene-butadiene rubber having a styrene content of 30% by mass or less.

16. The tire according to any one of claims 1 to 3, wherein the modulus of the rubber composition when stretched 200% is M 200 When the rubber composition M 200 , 30℃E* and 30℃tanδ satisfy the following formula (1), where M 200 The unit is MPa, M 200 ×30℃E* / 30℃tanδ≥100· · · (1)。

Images