TIRES

Abstract

A tire comprising a tread section and a belt layer, wherein the tread section has at least one layer of rubber, wherein the belt layer comprises a steel cord and a cover rubber covering the steel cord, wherein a rubber top layer, which forms a tread surface of the tread section, and the top rubber are each composed of a rubber composition comprising a rubber component and a filler, where a complex elastic modulus at 70 °C of the surface rubber (70 °CE*1) is 15.0 MPa or less, and where in a case where W L in kg represents the maximum load capacity of the tire and 70 °C-tanδ1 represents a tanδ at 70 °C of the outer rubber, W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33 × 10 − 5 × WL − 70 °C − tan δ 1 > 0.023

Description

TECHNICAL AREA

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

[0002] There is a need for a tire that excels in durability, thus reducing the need for frequent tire replacements and allowing for extended use. PATENT DOCUMENT 1 discloses a steel element for reinforcing a rubber product, wherein the steel element is covered with a coating material made of a ternary or quaternary copper-M-zinc alloy, and a reinforced rubber article comprising the steel element and a rubber compound. QUOTE LIST PATENT DOCUMENT

[0003] [PATENT DOCUMENT 1] JP 2015-511998 A SUMMARY OF THE INVENTIONAL PROBLEM

[0004] In PATENT DOCUMENT 1, a specific degree of durability when the rubber article is used as a tire is not clear, and there is room for improvement in this regard.

[0005] One object of the present invention is to improve the durability of a tire. SOLUTION TO THE PROBLEM

[0006] The present invention relates to a tire comprising a tread section and a belt layer, wherein the tread section has at least one rubber layer, wherein the belt layer comprises a steel cord and a cover rubber covering the steel cord, wherein a rubber cover layer forming a tread surface of the tread section and the cover rubber are each composed of a rubber composition comprising a rubber component and a filler, wherein a complex modulus of elasticity at 70 °C of the cover rubber (70 °CE*1) is 15.0 MPa or less, and wherein in a case where W L in kg represents the maximum load capacity of the tire and 70 °C-tanδ1 represents a tanδ at 70 °C of the outer rubber, W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33×10−5×WL−70 °C−tanδ1>0.023 ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] According to the present invention, the durability of a tire can be improved. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a cross-sectional view of a tire according to an embodiment of the present invention. Fig. Figure 2 is a view that schematically shows a belt layer. Fig. Figure 3 is an illustrative view of a configuration example of a simply twisted steel cord. DETAILED DESCRIPTION

[0008] The tire, which is an embodiment of the present invention, is a tire comprising a tread section and a belt layer, wherein the tread section has at least one rubber layer, wherein the belt layer comprises a steel cord and a cover rubber covering the steel cord, wherein a rubber cover layer forming a tread surface of the tread section and the cover rubber are each composed of a rubber composition comprising a rubber component and a filler, wherein a complex modulus of elasticity at 70 °C of the cover rubber (70 °CE*1) is 15.0 MPa or less, and wherein in a case where W L in kg represents the maximum load capacity of the tire and 70 °C-tanδ1 represents a tanδ at 70 °C of the outer rubber, W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33×10−5×WL−70 °C−tanδ1>0.023

[0009] Although it is not intended to be bound to any theory, one reason why the durability of the tire of the present invention is improved is assumed to be as follows.

[0010] It is assumed that if the virtual volume (air capacity) of the tire increases, the maximum load capacity W also increases. L The tire's resistance is increased, making it possible to suppress deformation amounts of the tread section and the belt layer. Therefore, when W L If the heat generation of the skin is low, deformation in the belt layer is relatively large, and thus the tire's durability is assumed to be easily improved by reducing the heat generation of the skin rubber (i.e., 70 °C tan δ1) covering the belt layer. On the other hand, if the heat generation of the skin rubber (i.e., 70 °C tan δ1) is high, the tire's durability is assumed to be easily improved by increasing W Land can improve the suppression of deformation amounts of the running surface section and the belt layer.

[0011] Furthermore, it is assumed that the occurrence of strain concentration in the belt layer due to extremely high stiffness of the belt layer is suppressed by adjusting the complex elastic modulus at 70 °C of the top rubber (70 °CE*1) to 15.0 MPa or less.

[0012] It is assumed that the interaction of these above features will achieve a remarkable effect that is able to improve the durability of the tire more effectively.

[0013] The filler incorporated into the rubber composition forming the top layer preferably comprises silicon dioxide.

[0014] By incorporating silicon dioxide into the outer rubber, the stiffness of the outer rubber can be reduced in an area of ​​minor deformation, thus improving adhesion to the steel cord outer rubber and further enhancing the tire's durability.

[0015] The filler incorporated into the rubber composition forming the top layer preferably comprises recovered carbon black.

[0016] The recovered carbon black exhibits a broader particle size distribution than regular carbon black. Therefore, compared to a case where regular carbon black is used, polymer movement can be suppressed even with respect to a wide range of frequencies introduced from a road surface, and heat generation of the outer rubber can be suppressed, so that the durability of the tire is assumed to be further improved.

[0017] The carbon black content, based on 100 parts by mass of the rubber component of the rubber composition forming the rubber cover layer, is preferably 20 parts by mass or less. Furthermore, the tanδ at 30 °C (30 °C tanδ²) of the rubber cover layer is preferably 0.16 or less.

[0018] By reducing the carbon black content in the rubber surface layer, etc., heat generation by the rubber surface layer is reduced, thus suppressing a relatively low tire surface temperature. Furthermore, by suppressing the heat generation of a surface element, heat generated in an internal tire element, such as a belt layer, is easily dissipated, which is believed to further improve tire durability.

[0019] If 30 °C-tanδ2 represents a tanδ at 30 °C of the rubber surface layer and 0 °C-tanδ2 represents a tanδ at 0 °C of the rubber surface layer, then 0 °C-tanδ2 / 30 °C-tanδ2 is preferably greater than 2.3.

[0020] By setting a tanδ² of 0 °C / 30 °C within the range described above, the rubber liner can be kept in a flexible state at a low temperature, thus suppressing strain concentration on the tire's inner element due to deformation caused by rolling over a wide temperature range. As a result, deterioration due to mechanical fatigue caused by deformation of the liner is suppressed, and tire durability is expected to be further improved.

[0021] The total amount of styrene in the rubber component forming the rubber top layer is preferably 15 wt% or less.

[0022] By adjusting the total amount of styrene in the rubber component forming the rubber top layer within the range described above, the complex modulus of elasticity can be reduced over the wide temperature range, particularly the low temperature range, even when bonding a styrene-butadiene rubber, which generally has a higher glass transition temperature than an isoprene-based rubber or a butadiene rubber, so that the rubber top layer can be assumed to be kept in the flexible state.

[0023] W L From the point of view of easily demonstrating the effects of the present invention, the number is preferably 400 or more.

[0024] The steel cord is preferably a simple monofilament cord.

[0025] It is assumed that the amount of deformation of the belt layer can be suppressed by using the steel cord as a non-twisted monofilament cord to increase the stiffness of the steel cord.

[0026] If S in mm 2 where S represents a cross-sectional area of ​​the steel cord and E represents the number of steel cords per 50 mm width in a direction perpendicular to a longitudinal direction of the steel cord, S × E is preferably 1.0 or more and 25 or less from the point of view of the effects of the present invention.

[0027] If Y in mass parts represents a silicon dioxide content based on 100 mass parts of the rubber component of the rubber composition forming the cover rubber, then Y / (S × E) is preferably 0.10 or more.

[0028] When silicon dioxide is incorporated into the top layer of rubber, the rubber becomes more acidic, which facilitates the detachment of a zinc oxide coating on a plated surface of the steel cord, thus assuming that an adhesive layer is efficiently formed. Here, if Y / (S × E) is set within the range described above, the advantage of adhesive layer formation due to acidification outweighs the advantage of adhesive layer thickening due to copper deposition, so good adhesive performance is assumed to be achieved.

[0029] The steel cord preferably has a ternary plating layer consisting of copper, zinc and cobalt.

[0030] When ternary plating is used, cobalt, which has a greater tendency to ionize than copper, preferentially elutes, thereby suppressing thickening of the adhesive layer due to copper elution after hygrothermal degradation, so that the adhesive strength is assumed to be maintained at a high level.

[0031] If G in kg represents a tire weight, then G / W is L Preferably 0.060 or less.

[0032] If G / W LWithin the range described above, the total amount of heat generation due to deformation can be suppressed by reducing the amount of rubber in the entire tire, while the total amount of heat generation due to deformation can be synergistically suppressed by ensuring a sufficient volume of air against a load, so that it is assumed that both durability and fuel efficiency can be achieved at a high level. <definitionen>

[0033] A "tread section" is a section that forms a ground contact area of ​​a tire, and in a case where the tire includes an element forming a tire skeleton of steel or textile material, such as a belt layer, belt reinforcement layer, carcass layer and the like, in a cross-section in a tire radial direction, the tread section is an element on an outside of it in the tire radial direction.

[0034] A “belt layer” is a layer provided on an outer surface in a tire radial direction with respect to a carcass layer, corresponding to several working layers in which internal reinforcing materials are inclined at an angle of approximately 18° to 30° relative to a tire circumferential direction and overlap in the opposite direction with a circumferential belt layer in which the internal reinforcing materials are oriented at an angle of ±10° relative to the tire circumferential direction, or the like.

[0035] A "standardized condition" is a condition in which a tire is mounted on a standardized rim and is filled with air under a standardized internal pressure and no load is applied.

[0036] Unless otherwise specified, a “dimension of each part of the tire” is a value specified in a standardized state for one appearing on the outer surface of the tire, while for one present inside the tire, or for one on a tire cut surface, it is a value specified in a state in which, for example, the tire is cut along a plane containing a tire axis of rotation and the cut piece of tire is held to a rim width of a standardized rim.

[0037] A "standardized rim" is a rim within a standard system that includes a standard on which the tire is based, and which is defined by the standard for each tire. For example, "standardized rim" refers to a "standard rim" of an applicable size described in the "Jatma Year Book" of JATMA (The Japan Automobile Tire Manufacturers Association, Inc.), a "measuring rim" described in the "STANDARDS MANUAL" of ETRTO (The European Tyre and Rim Technical Organisation), or a "design rim" described in the "YEAR BOOK" of TRA (The Tire and Rim Association, Inc.), referenced in that order, and if an applicable size exists at the time of reference, the rim conforms to its standard.Furthermore, in the case of tires not defined by the standard, the standardized rim shall refer to a rim that can be mounted on the tire and whose width is the narrowest among rims that have the smallest diameter capable of maintaining internal pressure (i.e., causing no air leakage between the rim and the tire).

[0038] A “standardized internal pressure” is an air pressure in a standard system containing a standard on which the tire is based, defined by the standard for each tire. It refers, for example, to a “MAXIMUM AIR PRESSURE” in JATMA, “INFLATION PRESSURE” in ETRTO, or a maximum value described in the “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” table in TRA, to which reference is made in that order, as in the case of the standardized rim, and if there is an applicable size at the time of reference, the standardized internal pressure conforms to its standard.Furthermore, in the case of tires not defined by the standard, the standardized internal pressure should refer to a standardized internal pressure (250 kPa or more) of another tire size (specified in the standard) for which the standardized rim is described as a standard rim, and if several standardized internal pressures of 250 kPa or more are described, it should refer to a minimum value below that.

[0039] A "tire weight G in kg" refers to the weight of a single tire, excluding the weight of the rim. Conversely, if a sound-dampening material, sealant, sensor, etc., is incorporated into a tire lumen, the weight G should include these components.

[0040] A "maximum load capacity (W)" L ) in kg" is a value calculated using the following equations, where Wt in mm represents the tire cross-sectional width, Ht in mm represents the tire cross-sectional height, and Dt in mm represents the tire outer diameter as measured under standardized conditions, differing from the "maximum load capacity" based on the load index defined by the JATMA standard. V is a virtual volume of space occupied by the tire. WL=0.000011×V+175V={(Dt / 2)2−(Dt / 2−Ht)2}×π×Wt

[0041] A “tire outer diameter Dt” refers to the outer diameter of a tire in a standardized condition.

[0042] A “tire cross-sectional width Wt” refers to a maximum width between outer surfaces of sidewalls in a standardized condition (excluding, if present, patterns or markings on a sidewall of a tire).

[0043] A “tire cross-sectional height Ht” refers to a radial height of a tire in a cross-section that includes a tire rotation axis of the tire, and can be calculated by (Dt-R) / 2, where R is a rim diameter of the tire.

[0044] A “cross-sectional area of ​​a steel cord” is a cross-sectional area of ​​the steel cord when it is cut in a plane perpendicular to a longitudinal direction of the steel cord.

[0045] A "plasticizer" is a material that imparts plasticity to a rubber component and is a component extracted from a rubber compound using acetone. The plasticizer comprises a plasticizer that is liquid at 25°C and a plasticizer that is solid at 25°C. However, it should not include wax or stearic acid, which are commonly used in the tire industry.

[0046] A "plasticizer content" also includes any amount of plasticizer contained in a stretched rubber component that was previously stretched with the plasticizer, such as oil, a resin component, a liquid rubber component, and the like. The same applies, for example, to an oil content, a resin component content, and a liquid rubber content; for instance, a stretching oil is included in the oil content if a stretching component is oil. <messverfahren>

[0047] "70 °CE*" is a complex modulus of elasticity measured using a dynamic viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 70 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±1%, and a defined strain mode. A sample for measuring 70 °CE* is a vulcanized rubber compound measuring 20 mm in length × 4 mm in width × 1 mm in thickness. When produced by cutting from a tire, it is cut from a tire liner such that one tire circumferential direction becomes a long side and one tire radial direction becomes a thickness direction.

[0048] “70 °C-tanδ” is a loss tangent measured using a dynamic viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 70 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±1%, and a strain mode. A sample for measurement is prepared in a similar manner to the 70 °CE* test.

[0049] "30 °C-tanδ" is a loss tangent measured using a dynamic viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and a strain mode. A sample for measuring 30 °C-tanδ is a vulcanized rubber compound measuring 20 mm in length × 4 mm in width × 1 mm in thickness. When produced by cutting from a tire, it is cut from a tread section such that one tire circumferential direction becomes a long side and one tire radial direction becomes a thickness direction.

[0050] "0 °C tanδ" is a loss tangent measured using a dynamic viscoelasticity measuring device (e.g., EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 0 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and a strain mode. A sample for measurement is prepared in a similar manner to that used for the 30 °C tanδ.

[0051] An “average thickness of a plating layer” is measured in accordance with JIS H 8501:1999.

[0052] A "styrene content" is a value determined by 1 H-NMR measurement is calculated and is applied, for example, to a rubber component with a repeating unit derived from styrene, such as an SBR and the like.

[0053] A “vinyl content (cis-1,2-bonded butadiene unit amount)” is a value calculated by infrared absorption spectrometry in accordance with JIS K 6239-2:2017 and applied to a rubber component with a repeating unit derived from butadiene, such as an SBR, a BR and the like.

[0054] A “cis content (cis-1,4-bonded butadiene unit amount)” is a value calculated by infrared absorption spectrometry in accordance with JIS K 6239-2:2017 and is applied to a rubber component with a repeating unit derived from butadiene, such as a BR and the like.

[0055] A "total styrene content in a rubber component" is the total mass-percentage of styrene units contained in 100 mass-percentage of a rubber component. This value is obtained by multiplying a styrene content in mass-percentage by a mass fraction in a rubber component to obtain a calculated value for each of the respective rubber components and then adding these values ​​together. Specifically, it is calculated as Σ (styrene content (mass-percentage) of each styrene-containing rubber × content (mass-percentage) of each styrene-containing rubber in the rubber component / 100).

[0056] A weight-mean molecular weight (Mw) can be calculated for a standard polystyrene based on measurements obtained by gel permeation chromatography (GPC) (e.g., GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). It is applied, for example, to SBR, BR, and the like.

[0057] The specific nitrogen adsorption surface area (N2SA) of carbon black is measured according to JIS K 6217-2:2017. The specific nitrogen adsorption surface area (N2SA) of silicon dioxide is measured using the BET method according to ASTM D3037-93.

[0058] An "average primary particle size" is calculated by taking the arithmetic mean of the particle sizes of 400 particles photographed with a transmission or scanning electron microscope. Regarding particle size, in cases where the particle is substantially circular, the diameter of the circle is defined as the particle size; in cases where it is needle- or rod-shaped, a minor axis is defined as the particle size; and in other cases, an equivalent circular diameter calculated from an electron micrograph is defined as the particle size. The equivalent circular diameter is calculated as "the positive square root of [4 × (particle area) / π]". The average primary particle size is applied to silicon dioxide, carbon black, etc.

[0059] A “softening point of a resin component” is specified as a temperature at which a ball falls when the softening point defined in JIS K 6220-1:2015 7.7 is measured using a ring-and-ball softening point measuring device.

[0060] A process for producing a tire, which is an embodiment of the present invention, is described in detail below. However, the following descriptions are for illustrative purposes only and are not intended to limit the technical scope of the present invention to this description. <reifen>

[0061] The tire according to one embodiment of the present invention is described below with reference to the drawings.

[0062] Fig. Figure 1 shows a cross-sectional view of a tire 11 according to the present embodiment along a plane passing through a tire axis of rotation. Although Fig. Figure 1 shows only a left section with respect to a midline (CL), but it also exhibits similar structures on the right side of the CL, with the CL acting as an axis of symmetry. As in Fig. As shown in Figure 1, the tire 11 comprises a tread section 12, a sidewall section 13, a bead section 14, an inner liner 15, a carcass 16, a belt layer 17 and a bead wire 18. The belt layer 17 has two layers, but the number of layers is not particularly restricted and can be chosen arbitrarily.

[0063] Fig. Figure 2 shows a cross-sectional view of a steel cord 21 along a plane perpendicular to a longitudinal direction. Each belt layer 17 has several steel cords 21 and a cover rubber 22. The multiple steel cords 21 are arranged parallel in a row. Furthermore, the cover rubber 22 covers the steel cord 21, and the entire circumference of each steel cord is covered by the cover rubber 22. The steel cord 21 is embedded in the cover rubber 22.

[0064] The steel cord 21 can be inclined or not inclined with respect to a tire circumference direction. The inclination angle of the steel cord 21 with respect to the tire circumference direction is not particularly restricted; however, it is preferably set in a range of 0° to 60°, preferably 5° to 45°, and more preferably 10° to 30°. (steel cord)

[0065] The steel cord according to the present embodiment comprises one or more steel wires, also referred to as filaments. The steel cord can be a simple monofilament cord (i.e., a cord with a 1 × 1 structure and consisting of one filament) or it can have multiple filaments; however, the monofilament cord is specified as a preferred aspect.

[0066] It is assumed that the amount of deformation of the belt layer can be suppressed by using the steel cord as a non-twisted monofilament cord to increase the stiffness of the steel cord.

[0067] If a steel cord has multiple filaments, it preferably has a twisted structure in which the multiple filaments are twisted together longitudinally. When the steel cord has multiple filaments, the twisted structure is not particularly restricted and can, for example, be a simply twisted steel cord with a structure of 1 × N or a layer-twisted steel cord with a structure of N + M.

[0068] The simply twisted structure can, for example, be expressed as a 1 × N structure. The 1 × N structure means a structure in which N filaments are twisted together to form a single layer. The "single layer" means a structure in which filaments are arranged to form a single layer along a circumferential direction of a circle in a cross-section perpendicular to a longitudinal direction of a steel cord. In the simply twisted structure, N is preferably 6 or less, more preferably 4 or less, and most preferably 2.

[0069] Fig. Figure 3 is a perspective view of a steel cord with a 1 × 2 structure. In a Fig. In the steel cord 50 shown, two filaments 51 are twisted together along a longitudinal direction in a spiral shape so that a single layer is formed.

[0070] The layered twisted structure has a structure in which several filaments are wound in layers from the central part in a cross-section perpendicular to a longitudinal direction of a steel cord, and can be expressed, for example, as an N + M structure. The N + M structure represents a structure that has a core in which N filaments are twisted together along the longitudinal direction in a helical shape, and an outer sheath in which M filaments are twisted together along the longitudinal direction of the core in a helical shape such that they cover the outer circumference of the core.

[0071] The material of the steel filament is not particularly restricted, and HT (High Tensile), SHT (Super High Tensile), UHT (Ultra High Tensile), etc., materials can be used. Furthermore, recycled iron obtained by melting down scrap iron products can be used. Additionally, if a steel cord obtained by twisting several steel filaments together is used, a steel filament pre-formed lengthwise can be employed to improve durability by facilitating the penetration of a cover rubber.

[0072] The filament diameter of the steel cord is not particularly restricted and can be arbitrarily selected depending on the required properties and the like. However, from the perspective of ensuring the steel cord's durability against impacts, it is preferably 0.10 mm or more, more preferably 0.13 mm or more, even more preferably 0.16 mm or more, even more preferably 0.19 mm or more, even more preferably 0.22 mm or more, even more preferably 0.25 mm or more, and particularly preferably 0.28 mm or more. Furthermore, from the perspective of sufficient shock absorption to improve ride comfort, it is preferably 0.70 mm or less, more preferably 0.60 mm or less, even more preferably 0.50 mm or less, even more preferably 0.45 mm or less, even more preferably 0.40 mm or less, and particularly preferably 0.35 mm or less.

[0073] The steel cord according to the present embodiment can be provided with a plating layer. Since the steel cord with a plating layer exhibits high adhesive strength, even under harsh conditions of high temperature and humidity, separation between the cover rubber and the steel cord can be prevented, and the tire's durability under warm, humid conditions can be improved. Furthermore, if the steel cord has multiple filaments, each filament can be provided with a plating layer on its surface.

[0074] The configuration of the plating layer is not particularly restricted; however, a plating layer comprising a copper layer and a zinc layer is preferred, and a plating layer comprising a copper layer, a zinc layer, and a cobalt layer is further preferred. Since the steel cord, which has a ternary plating layer consisting of copper (Cu), zinc (Zn), and cobalt (Co), exhibits high adhesive strength even under harsh conditions of high temperature and humidity, separation between the outer rubber and the steel cord can be prevented, and the durability of the tire under humid, warm conditions can be improved.

[0075] To suppress excessive copper reaction, the zinc content in the plating layer is preferably 15 wt% or more, more preferably 20 wt% or more, and even more preferably 25 wt% or more. Furthermore, to suppress decreased adhesion due to the formation of excessive zinc oxide, the zinc content is preferably 44 wt% or less, more preferably 40 wt% or less, even more preferably 36 wt% or less, and particularly preferably 32 wt% or less.

[0076] For the sake of adhesive performance, the copper content in the plating layer is preferably 55 wt% or more, more preferably 58 wt% or more, and even more preferably 61 wt% or more. Furthermore, for the sake of preventing rubber deterioration due to copper elution in a hygrothermal environment, it is preferably 78 wt% or less, more preferably 75 wt% or less, and even more preferably 72 wt% or less.

[0077] For the purpose of achieving moist-temperature adhesive performance, the cobalt content in the plating layer is preferably 1.0 wt% or more, more preferably 2.0 wt% or more, and even more preferably 3.0 wt% or more. Furthermore, for the purpose of preventing cracking during wire drawing, the cobalt content is preferably 8.0 wt% or less, more preferably 7.0 wt% or less, and even more preferably 6.0 wt% or less.

[0078] The plating layer can be formed by plating a copper layer, a zinc layer, a cobalt layer, etc., onto the filament before wire drawing and then diffusing the metal from each layer formed on the filament's surface through heat treatment. Furthermore, the sequence of lamination layers on the filament to form the plating layer is not particularly restricted.

[0079] Next, a filament with a plating layer can be formed by wire drawing the heat-treated material to achieve the desired filament diameter. If the steel cord is built from a single filament, it can be used as is after wire drawing. Furthermore, if the steel cord consists of multiple filaments, a steel cord with a plated layer can be formed, for example, by twisting the resulting filaments together, so that after wire drawing it exhibits a desired twisted structure.

[0080] The average thickness of the plating layer, from the perspective of initial adhesive performance, is preferably 0.10 µm or more, more preferably 0.13 µm or more, and even more preferably 0.16 µm or more. Furthermore, from the perspective of suppressing excessive adhesion, it is preferably 0.40 µm or less, more preferably 0.35 µm or less, and even more preferably 0.30 µm or less.

[0081] The cross-sectional area S of the steel cord is preferably 0.04 mm². 2 or more, preferably 0.05 mm 2 or more, preferably 0.06 mm 2 or more and especially preferably 0.07 mm 2 or more. Furthermore, the cross-sectional area S of the steel cord is preferably 0.80 mm². 2 or less, preferably 0.60 mm 2 or less, preferably 0.40 mm 2 or less, preferably 0.30 mm 2 or less, preferably 0.25 mm 2 or less and especially preferably 0.20 mm 2 or less.

[0082] The number E (also referred to as ends) of steel cords per 50 mm width in a direction perpendicular to a longitudinal direction of a steel cord is, however, not particularly limited to, preferably 20 or more, more preferably 25 or more, still more preferably 30 or more, still more preferably 35 or more, and particularly preferably 40 or more. Furthermore, E is preferably 90 or less, more preferably 80 or less, still more preferably 70 or less, and particularly preferably 60 or less.

[0083] The product of S and E (S × E) is preferably 1.0 or more, more preferably 2.0 or more, even more preferably 3.0 or more, even more preferably 4.0 or more, even more preferably 5.0 or more, and particularly preferably 5.5 or more. Furthermore, the product of S and E is preferably 25 or less, more preferably 20 or less, even more preferably 15 or less, even more preferably 12 or less, even more preferably 10 or less, and particularly preferably 8.0 or less. Additionally, the product of S and E is an index representing the quantity of steel cords per unit cross-sectional area.

[0084] If Y in parts by mass represents a silicon dioxide content based on 100 parts by mass of a rubber component of a rubber composition forming a cover rubber, then Y / (S × E) is preferably 0.10 or more, more preferably 0.30 or more, still more preferably 0.50 or more, still more preferably 0.75 or more, still more preferably 1.0 or more, and particularly preferably 1.2 or more. When silicon dioxide is incorporated into the cover rubber, the rubber becomes more acidic, which facilitates the detachment of a zinc oxide coating on a plated surface of the steel cord, thus efficiently forming an adhesive layer. Here, if Y / (S × E) is set within the range described above, the advantage of adhesive layer formation due to acidification outweighs the advantage of adhesive layer thickening due to copper deposition, so good adhesive performance is expected to be achieved.On the other hand, an upper limit of Y / (S × E) is preferably 20 or less, more preferably 10 or less, even more preferably 5.0 or less and most preferably 2.5 or less, but is not particularly restricted thereto.

[0085] The maximum load capacity W L The weight in kg of the tire, from the perspective of better demonstrating the effects of the present invention, is preferably 400 or more, more preferably 500 or more, still more preferably 600 or more, still more preferably 700 or more, and particularly preferably 800 or more. Furthermore, W L preferably 1,300 or less, further preferably 1,200 or less, and even more preferably 1,100 or less. Furthermore, W L The virtual volume V of the space occupied by the tire can be increased, and it can also be decreased by decreasing the virtual volume V of the space occupied by the tire.

[0086] If G in kg represents a tire weight, then G / W is L From the perspective of the effects of the present invention, preferably 0.060 or less, more preferably 0.040 or less, even more preferably 0.025 or less, and particularly preferably 0.020 or less. On the other hand, a lower limit of G / W is L not particularly restricted, but can be, for example, 0.012 or more, 0.013 or more, or 0.014 or more. Furthermore, the tire weight G can be changed by a conventional method, that is, it can be increased by increasing the specific gravity of the tire or by increasing the thickness of each element of the tire, and it can be decreased by decreasing the specific gravity of the tire or by decreasing the thickness of each element of the tire.

[0087] The complex modulus of elasticity at 70 °C of the surface rubber (70 °CE*1), from the perspective of the effects of the present invention, is 15.0 MPa or less, preferably 14.0 MPa or less, more preferably 12.0 MPa or less, even more preferably 10.0 MPa or less, even more preferably 9.0 MPa or less, even more preferably 8.0 MPa or less, and particularly preferably 7.0 MPa or less. On the other hand, a lower limit of 70 °CE*1 is preferably 2.0 MPa or more, more preferably 3.0 MPa or more, and even more preferably 4.0 MPa or more, but is not specifically limited to these values.

[0088] The tanδ at 70 °C of the top layer rubber (70 °C tanδ1) is, from the perspective of the effects of the present invention, preferably 0.079 or less, more preferably 0.065 or less, even more preferably 0.052 or less, even more preferably 0.046 or less, even more preferably 0.040 or less, even more preferably 0.036 or less, and particularly preferably 0.033 or less. On the other hand, a lower limit of 70 °C tanδ1 is preferably 0.020 or more, more preferably 0.023 or more, and even more preferably 0.026 or more, but is not specifically limited to these values.

[0089] The tire according to the present embodiment is characterized in that W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33×10−5×WL−70 °C−tanδ1>0.023

[0090] Here is 9.33 × 10 -5 × W L - 70 °C-tanδ1, from the perspective of the effects of the present invention, is preferably greater than 0.024, more preferably greater than 0.030, even more preferably greater than 0.035, and particularly preferably greater than 0.040. On the other hand, an upper limit of 9.33 × 10 -5 × W L - 70 °C-tanδ1 preferably less than 0.090, further preferably less than 0.085, even more preferably less than 0.080 and most preferably less than 0.075, but is not particularly restricted in this respect.

[0091] The tanδ at 30 °C of the rubber surface layer (30 °C tanδ2) is, from the perspective of heat generation, preferably 0.25 or less, more preferably 0.23 or less, even more preferably 0.20 or less, even more preferably 0.18 or less, even more preferably 0.16 or less, even more preferably 0.15 or less, and particularly preferably 0.14 or less. On the other hand, from the perspective of ride comfort, 30 °C tanδ2 is preferably 0.03 or more, more preferably 0.05 or more, even more preferably 0.07 or more, and particularly preferably 0.09 or more.

[0092] The tanδ at 0 °C of the rubber top layer (0 °C tanδ2) is, from the perspective of fuel efficiency at low temperatures, preferably 0.42 or less, more preferably 0.40 or less, even more preferably 0.38 or less, even more preferably 0.36 or less, and particularly preferably 0.34 or less. On the other hand, from the perspective of wet adhesion performance, 0 °C tanδ2 is preferably 0.07 or more, more preferably 0.10 or more, even more preferably 0.12 or more, even more preferably 0.15 or more, and particularly preferably 0.18 or more.

[0093] The 0 °C tanδ2 / 30 °C tanδ2 is preferably greater than 1.4, more preferably greater than 1.5, still more preferably greater than 1.7, still more preferably greater than 1.9, still more preferably greater than 2.1%, and most preferably greater than 2.3%. By setting the 0 °C tanδ2 / 30 °C tanδ2 within the ranges described above, the rubber liner can be kept in a flexible state over a low temperature range, thus suppressing strain concentration on the tire's inner element due to deformation caused by rolling over a wide temperature range. Consequently, deterioration due to mechanical fatigue caused by deformation of the liner rubber is suppressed, and the tire's durability is further improved. On the other hand, an upper limit of 0 °C-tanδ2 / 30 °C-tanδ2 is preferably less than 3.0 and more preferably less than 2.8, but is not particularly restricted thereto. [Rubber composition]

[0094] The rubber composition forming the liner and the rubber composition forming the tread section of the tire according to the present embodiment (hereinafter referred to as the rubber compositions according to the present embodiment) each comprise a rubber component and a filler and can be produced using the raw materials described below. The rubber compositions according to the present embodiment are described below; however, unless otherwise specified, the description applies to both the rubber composition forming the tread section and the rubber composition forming the liner. <kautschukkomponente>

[0095] In the rubber composition according to the present embodiment, a diene-based rubber is suitably used as one of the rubber components. Examples of diene-based rubbers include, for example, isoprene-based rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like. Furthermore, these diene-based rubbers can be modified rubbers treated with modification groups capable of interacting with fillers such as carbon black, silicon dioxide, and the like, or they can be hydrogenated rubbers obtained by hydrogenating a portion of an unsaturated bond. The diene-based rubber can be used alone, or two or more of them can be used in combination.Furthermore, as a diene-based rubber, a stretched rubber can be used which has previously been stretched with a plasticizer, which will be mentioned later.

[0096] The content of the diene-based rubber in the rubber component is preferably 70 wt% or more, more preferably 80 wt% or more, even more preferably 90 wt% or more, and particularly preferably 95 wt% or more. Furthermore, the rubber component can be one consisting of a diene-based rubber.

[0097] The diene-based rubber component is at least one selected from the group consisting of an isoprene-based rubber, an SBR, and a BR. The diene-based rubber component preferably comprises an isoprene-based rubber, more preferably an isoprene-based rubber and an SBR and / or a BR, more preferably an isoprene-based rubber and an SBR, and most preferably an isoprene-based rubber, a BR, and an SBR. (Isoprene-based rubber)

[0098] Isoprene-based rubbers can include those commonly used in the tire industry, such as isoprene rubber (IR), natural rubber, and the like. Examples of natural rubber include unreformed natural rubber (NR), as well as refined natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), ultrapure natural rubber, grafted natural rubber, and the like. These isoprene-based rubbers can be used individually, or two or more can be used in combination.

[0099] The NR is not particularly restricted, and those commonly used in the tire industry can be used, examples of which include SIR20, RSS#3, TSR20 and the like.

[0100] From the perspective of the effects of the present invention, the content of isoprene-based rubber in the rubber component forming the top layer is preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, and particularly preferably 90% by weight or more. On the other hand, the upper limit of the content is not particularly restricted and can be 100% by weight.

[0101] From the perspective of the effects of the present invention, the content of isoprene-based rubber in the rubber component forming the rubber surface layer is preferably 70 wt% or less, more preferably 60 wt% or less, even more preferably 50 wt% or less, and particularly preferably 45 wt% or more. On the other hand, a lower limit for the content is not particularly restricted; it may, for example, be 1 wt% or more, 5 wt% or more, 10 wt% or more, or 15 wt% or more. (SBR)

[0102] The SBR is not particularly restricted; examples include an unmodified solution-polymerized SBR (S-SBR), an emulsion-polymerized SBR (E-SBR), modified SBRs (a modified S-SBR, a modified E-SBR) thereof, and the like. Examples of modified SBRs include an SBR modified at its end and / or main chain, a modified SBR coupled with tin, a silicon compound, etc. (a modified SBR of condensate or with a branched structure, etc.), and the like. Among these, an S-SBR and a modified SBR are preferred. Furthermore, hydrogenated versions of these SBRs (hydrogenated SBRs) and the like may also be used. These SBRs may be used individually, or two or more of them may be used in combination.

[0103] According to the present embodiment, both extended and non-extended SBRs can be used. The amount of extension in the extended SBR, that is, the amount of an extension plasticizer contained in the SBR when used, is preferably 10 to 50 parts by mass based on 100 parts by mass of a rubber solids content of the SBR.

[0104] Examples of SBRs that can be used include those listed above that are commercially available from Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, ZS Elastomer Co., Ltd., etc.

[0105] The styrene content of an SBR is preferably 40 wt% or less, more preferably 36 wt% or less, even more preferably 32 wt% or less, and particularly preferably 28 wt% or less. Furthermore, the styrene content of the SBR is preferably 5 wt% or more, more preferably 7 wt% or more, even more preferably 10 wt% or more, and particularly preferably 12 wt% or more. The styrene content of the SBR is also measured using the measurement method described above.

[0106] The vinyl content of the SBR is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, to ensure reactivity with silicon dioxide and abrasion resistance. Furthermore, to improve elongation at break and abrasion resistance, the vinyl content of the SBR is preferably 45 mol% or less, more preferably 40 mol% or less, and even more preferably 35 mol% or less. The vinyl content of the SBR is also measured using the method described above.

[0107] From the perspective of the effects of the present invention, the weight-average molecular weight (Mw) of the SBR is preferably 100,000 or more, more preferably 200,000 or more, and even more preferably 300,000 or more. Furthermore, from the perspective of crosslinking uniformity, it is preferably 2,000,000 or less, more preferably 1,800,000 or less, and even more preferably 1,500,000 or less. The weight-average molecular weight of the SBR is also measured using the measurement method described above.

[0108] The SBR content in the rubber component forming the cover rubber is preferably 40 wt% or less, more preferably 20 wt% or less, even more preferably 10 wt% or less and particularly preferably 5 wt% or less, but is not particularly restricted thereto.

[0109] The content of SBR in the rubber component forming the rubber surface layer can, for example, be selected such that the total styrene content in the rubber component forming the rubber surface layer meets the ranges mentioned later, but is preferably 85 wt% or less, more preferably 80 wt% or less, still more preferably 75 wt% or less, and most preferably 70 wt% or less. On the other hand, a lower limit for the content is not particularly restricted, but it can, for example, be 1 wt% or more, 5 wt% or more, 10 wt% or more, or 15 wt% or more. (BR)

[0110] The type of rubber (BR) is not particularly restricted, and those commonly used in the tire industry can be employed, such as a BR with a cis content of less than 50 mol% (a cis-poor BR), a BR with a cis content of 90 mol% or more (a cis-rich BR), a rare-earth-based butadiene rubber synthesized using a rare-earth-based catalyst (a rare-earth-based BR), a BR containing a syndiotactic polybutadiene crystal (an SPB-containing BR), a modified BR (a cis-rich modified BR, a cis-poor modified BR), and the like. These BRs can be used individually, or two or more of them can be used in combination.

[0111] For example, cis-rich BR materials commercially available from Zeon Corporation, Ube Industries, Ltd., JSR Corporation, etc., can be used. When the cis-rich BR is used, abrasion resistance can be improved. The cis content of the cis-rich BR is preferably 95 mol% or more, more preferably 96 mol% or more, and even more preferably 97 mol% or more. Furthermore, the cis content of the BR is measured using the measurement method described above.

[0112] The content of BR in the rubber component forming the cover rubber is, but not particularly restricted, preferably 40 wt% or less, more preferably 20 wt% or less, even more preferably 10 wt% or less and particularly preferably 5 wt% or less.

[0113] From the perspective of the effects of the present invention, the content of BR in the rubber component forming the rubber cover layer is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and particularly preferably 20 parts by mass or more, and particularly preferably 30 parts by mass or more. Furthermore, the content is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, and particularly preferably 45% by mass or less.

[0114] From the perspective of the effects of the present invention, the total amount of styrene in the rubber component forming the rubber top layer is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 13% by mass or more. Furthermore, a lower limit for the total amount of styrene in the rubber component is, but not specifically limited, preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and particularly preferably 7% by mass or more. (Other rubber components)

[0115] The rubber component may comprise rubber components other than diene-based rubbers, provided they do not impair the effects of the present invention. Examples of rubber components other than diene-based rubbers include crosslinkable rubber components commonly used in the tire industry, such as non-diene-based rubbers like butyl rubber (IIR), halogenated butyl rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, polyethylene chloride rubber, fluororubber (FKM), acrylic rubber (ACM), hydrin rubber, and the like. Furthermore, the rubber component may or may not include a known thermoplastic elastomer, in addition to the rubber components described above.Other rubber components can be used alone, or two or more of them can be used in combination. (Rubber component synthesized from recycled / biomass-derived raw material)

[0116] A monomer that forms a structural unit of a synthetic rubber, such as SBR, BR, and the like, can be petroleum-derived or recycled from a rubber product, such as a tire, or from a non-rubber product, such as polystyrene. The monomer obtained through recycling (recycled monomer) is not particularly restricted; examples include recycled butadiene, recycled aromatic vinyl compounds, and the like. Examples of butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The aromatic vinyl compound described above is not particularly restricted; examples include styrene and the like. Among these, recycled butadiene and / or recycled styrene are preferred as raw materials.

[0117] A process for producing a recycled monomer is not particularly restricted; examples include, for instance, a process for synthesizing a monomer from a recycled naphtha obtained by decomposing a rubber product, such as a tire, etc. Furthermore, a process for producing a recycled naphtha is not particularly restricted and can, for example, be obtained by decomposing a rubber product, such as a tire, etc., under high temperature and high pressure, by decomposing it using microwaves, or by extracting it after mechanical pulverization.

[0118] Furthermore, a monomer that is a structural unit of a polymer, such as an SBR, a BR, and the like, can be a biomass-derived monomer. The biomass-derived monomer (biomass monomer) is not particularly restricted; examples include biomass-derived butadiene, biomass-derived aromatic vinyl compounds, and the like. Examples of butadiene include 1,2-butadiene, 1,3-butadiene, and the like. The aromatic vinyl compound described above is not particularly restricted, and examples include styrene and the like. Moreover, the method of producing a biomass monomer is not particularly restricted; examples include, for instance, a biological and / or chemical and / or physical transformation of animals and plants, and the like.Microbial fermentation is representative of biological conversion, and examples of chemical and / or physical conversion include that due to a catalyst, high heat, high pressure, electromagnetic waves, critical fluids, and combinations thereof. Examples of biomass sources for these monomers include sugars, wood, plant residues after the extraction of a useful component, plant-derived ethanol, biomass naphtha, and the like.

[0119] A polymer synthesized from a biomass monomer component (biomass polymer) is not particularly restricted; examples include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl, and the like. Examples of aromatic vinyl butadiene copolymer include, for instance, styrene butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene, and the like.

[0120] Whether a polymer raw material is derived from biomass can be determined by pMC (percent modern carbon), measured according to ASTM D6866-10. Here, pMC is a ratio of 14 C concentration of a sample to 14 The carbon concentration of a modern standard reference medium is used as an index indicating the biomass ratio of a compound (rubber). The meaning of this value is explained below.

[0121] In 1 mol of carbon atoms (6.02 × 10 23 (Pieces) are approximately 6.02 × 10 11 14 C are present, which are about one trillionth the number of normal carbon atoms. A half-life of 14 C is 5730 years, and 14 Carbon content decreases regularly. Therefore, in the case of fossil fuels such as coal, oil, natural gas, and the like, where it is assumed that 226,000 years or more have passed since carbon dioxide was absorbed into the atmosphere by plants to be stored, all the carbon dioxide is decaying. 14 Carbon elements, which were present at the beginning of the fixation. Therefore, fossil fuels, such as coal, oil, natural gas and the like, do not contain any carbon in the current 21st century. 14 Carbon element. Therefore, chemical substances produced using these fossil fuels as raw materials also contain no carbon. 14 C-element.

[0122] On the other hand 14 C is constantly produced by cosmic rays that cause nuclear reactions in the atmosphere. Thus, a decrease of 14 C due to radioactive decay and the production of 14 C is balanced due to nuclear reactions and is the amount of 14 The temperature C in the Earth's atmospheric environment is constant. Therefore, the 14 Carbon concentration of substances derived from biomass resources that have circulated in the current environment to a value of approximately 1 × 10 -12 Molar percentage, based on total carbon atoms. Accordingly, by using the difference between these values, a ratio (biomass ratio) of compounds derived from natural resources (compounds derived from biomass resources) in a specific compound (rubber) can be calculated.

[0123] This 14 C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, a 13 C concentration ( 13 C / 12 C) and a 14 C concentration ( 14 C / 12 C) measured. During the measurements, a 14 Carbon concentration in a circulating carbon in nature from 1950 as the modern standard reference for the 14 C concentration is used. A standard oxalic acid body provided by the National Institute of Standards and Technology (NIST) is used as a specific reference material. A specific radioactivity of carbon in this oxalic acid (radioactivity intensity of 14 C per gram of carbon) is sorted for each carbon isotope. 13 C is corrected to a constant value, and a value corrected for attenuation from 1950 to the measurement date is considered a standard. 14 A carbon concentration value (100%) is used. A ratio of this value to an actual measured value for a sample is called a pMC value.

[0124] Thus, if a rubber is produced from a material derived 100% from biomass (naturally), it exhibits a value of approximately 110 pMC (currently, it often does not reach 100 under normal conditions), although there are regional variations. On the other hand, if this 14 When measuring the carbon concentration of a chemical substance derived from a fossil fuel, such as petroleum, it is approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%, as mentioned above.

[0125] Based on the above, it is suitable in terms of environmental protection to use a material, such as rubber, that has a high pMC value, i.e. a material, such as rubber, that has a high biomass ratio, for a rubber composition. <Füllstoff>

[0126] The rubber composition according to the present embodiment preferably comprises silicon dioxide as a filler and further preferably comprises silicon dioxide and carbon black. In addition, the filler can be a filler consisting of silicon dioxide and carbon black. (Silicon dioxide)

[0127] Silicon dioxide is not particularly restricted, and those commonly used in the tire industry can be employed, such as silicon dioxide produced by a dry process (anhydrous silicon dioxide), silicon dioxide produced by a wet process (hydrous silicon dioxide), and the like. The source of silicon dioxide is not particularly restricted and can be, for example, a mineral-derived raw material, such as quartz, a biomaterial-derived raw material, such as rice husks (e.g., silicon dioxide produced from a biomass material, such as rice husks), or silicon dioxide recycled from a silicon dioxide-containing product. Among these, hydrous silicon dioxide produced by a wet process is preferred because it contains many silanol groups.This silicon dioxide can be used alone, or two or more of them can be used in combination.

[0128] Silicon dioxide produced from a biomass material can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks, using a sodium hydroxide solution, and in the same way as conventional wet silicon dioxide, filtering, washing with water, drying and pulverizing precipitates of silicon dioxide produced by reacting with sulfuric acid, using the silicate.

[0129] Silicon dioxide recycled from a product containing silicon dioxide can include, for example, silicon dioxide recovered from an electronic component, such as a semiconductor, a tire, a product containing silicon dioxide, such as a desiccant, a filter material, such as diatomaceous earth, and the like. Furthermore, the recovery method is not particularly restricted; examples include pyrolysis, decomposition by electromagnetic waves, and the like. Silicon dioxide recovered from an electronic component, such as a semiconductor, or from a tire is preferred.

[0130] When silicon dioxide crystallizes, it is insoluble in water, and silicic acid, a component of it, cannot be used. Crystallization of silicon dioxide in rice hull ash can be suppressed by controlling the firing temperature and duration (JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222 etc.).

[0131] Amorphous silicon dioxide extracted from rice husks can be used, including those commercially available from Wilmar, etc.

[0132] The specific nitrogen adsorption surface area (N2SA) of silicon dioxide is preferably 100 m² from the perspective of abrasion resistance and elongation at break. 2 / g or more, preferably 120 m 2 / g or more, preferably 140 m 2 / g or more and especially preferably 160 m 2 / g or more. Furthermore, from the perspective of heat generation and processability, it is preferably 350 m³. 2 / g or less, preferably 300 m 2 / g or less and preferably 250 m 2 / g or less. Furthermore, the N2SA of silicon dioxide is measured using the measurement method described above.

[0133] An average primary particle size of silicon dioxide is preferably 20 nm or less, more preferably 18 nm or less, even more preferably 17 nm or less, and particularly preferably 16 nm or less. A lower limit for the average primary particle size, considering the dispersibility of silicon dioxide, is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more, but is not specifically restricted to these values. Furthermore, the average primary particle size of silicon dioxide is measured using the measurement method described above.

[0134] From the perspective of the effects of the present invention, the silicon dioxide content Y, in parts by mass, based on 100 parts by mass of the rubber component of the rubber composition forming the cover rubber, is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more. Furthermore, from the perspective of tire strength, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0135] From the perspective of the effects of the present invention, the silicon dioxide content, based on 100 parts by mass of the rubber component of the rubber composition forming the rubber top layer, is preferably 1 part by mass or more, more preferably 4 parts by mass or more, even more preferably 7 parts by mass or more, and particularly preferably 10 parts by mass or more. Furthermore, the content is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less. (Soot)

[0136] Carbon black is not particularly restricted, and those commonly used in the tire industry can be employed, such as GPF, FEF, HAF, ISAF, SAF, and the like. In particular, N110, N115, N120, N125, N134, N135, N219, N220, N231, N234, N293, N299, N326, N330, N339, N343, N347, N351, N356, N358, N375, N539, N550, N582, N630, N642, N650, N660, N683, N754, N762, N765, N772, N774, N787, N907, N908, N990, N991, and the like are suitable. Internally synthesized products and the like can also be used. A raw material for carbon black can be a biomass material, such as lignin, a vegetable oil, and the like, or it can be a pyrolysis oil obtained by pyrolyzing a used tire.Furthermore, carbon black can be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by pyrolysis of methane, such as a thermal carbon black process. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan KK, Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Chemical Carbon Co., Ltd., Columbian Carbon Japan Ltd., etc. These carbon blacks can be used individually, or two or more can be used in combination.

[0137] In this description, "recovered carbon black" refers to carbon black obtained by pulverizing a product such as a used tire containing carbon black and the like, and burning the pulverized product. When the product is subjected to oxidative combustion by heating in air using a thermal weight measurement method in accordance with JIS K 6226-2:2003, the ratio of a mass of ash (ash content), which is a non-combustible component, is 13% by mass or greater. That is, the ratio of a mass (amount of carbon) of a weight loss content due to the oxidative combustion of the recovered carbon black is 87% by mass or less. The recovered carbon black can be expressed in terms of rCB.

[0138] The recovered carbon black can be obtained from a pyrolysis process of a used pneumatic tire. EP3427975 A, for example, describes, with reference to “Rubber Chemistry and Technology”, Vol. 85, No. 3, pages 408 to 449 (2012), in particular pages 438, 440 and 442, that the recovered carbon black can be obtained by pyrolysis of an organic material at 550 to 800 °C in the absence of oxygen or by vacuum pyrolysis at a relatively low temperature (

[0027] ). As mentioned in

[0004] of JP 6856781 B (A comparison of surface morphology and chemistry of pyrolytic carbon blacks with commercial carbon blacks, Powder Technology 160 (2005) 190-193), such carbon black obtained by the pyrolysis process typically lacks a functional group on its surface.

[0139] The recovered carbon black may lack a functional group on its surface, or it may be treated so that its surface includes a functional group. The treatment, which is carried out so that the surface of the recovered carbon black includes a functional group, can be implemented by a conventional method. In EP 3173251 A, carbon black comprising a hydroxyl and / or carboxyl group on its surface is obtained by treating carbon black obtained from a pyrolysis process with potassium permanganate under acidic conditions. Furthermore, in JP 6856781 B, carbon black with an activated surface is obtained by treating carbon black obtained from a pyrolysis process with an amino acid compound comprising at least one thiol or disulfide group. The recovered carbon black according to the present embodiment also includes carbon black whose surface has been treated to include a functional group.

[0140] The recovered carbon black can be that which is commercially available from Strebl Green Carbon Pte Ltd., LDC Co., Ltd. etc.

[0141] The filler incorporated into the rubber compound forming the tread rubber preferably comprises recovered carbon black. Recovered carbon black exhibits a broader particle size distribution than regular carbon black. Therefore, compared to the use of regular carbon black, polymer movement can be suppressed even across a wide range of frequencies introduced from a road surface, and heat generation from the tread rubber can be reduced, thus further improving tire durability.

[0142] A specific nitrogen adsorption surface area (N2SA) of carbon black when it is incorporated into the rubber composition forming the cover rubber is preferably 20 m² from the point of view of the effects of the present invention. 2 / g or more, preferably 40 m 2 / g or more, preferably 50 m 2 / g or more and especially preferably 60 m 2 / g or more. Furthermore, from the perspective of fuel efficiency and processability, it is preferably 200 m³. 2 / g or less, preferably 150 m 2 / g or less and even more preferably 120 m 2 / g or less. Furthermore, the N2SA of soot is measured using the measurement method described above.

[0143] An average primary particle size of carbon black incorporated into the rubber composition forming the cover rubber is preferably 45 nm or less, more preferably 40 nm or less, still more preferably 35 nm or less, and particularly preferably 32 nm or less. A lower limit for the average primary particle size is, but not particularly restricted, preferably 5 nm or more, more preferably 8 nm or more, and still more preferably 10 nm or more. Furthermore, the average primary particle size of carbon black is measured by the measurement method described above.

[0144] A specific nitrogen adsorption surface area (N2SA) of carbon black, when combined in the rubber composition forming the rubber cover layer, is preferably 30 m² from the point of view of reinforcing properties. 2 / g or more, preferably 50 m 2 / g or more, preferably 70 m 2 / g or more and especially preferably 90 m 2 / g or more. Furthermore, from the perspective of fuel efficiency and processability, it is preferably 200 m³. 2 / g or less, preferably 150 m 2 / g or less and even more preferably 120 m 2 / g or less.

[0145] The average primary particle size of carbon black incorporated into the rubber composition forming the cover rubber is preferably 36 nm or less, more preferably 32 nm or less, still more preferably 28 nm or less, and particularly preferably 24 nm or less. A lower limit for the average primary particle size is, but not particularly restricted, preferably 5 nm or more, more preferably 8 nm or more, and still more preferably 10 nm or more.

[0146] From the perspective of elongation at break, the carbon black content, based on 100 parts by mass of the rubber component of the rubber composition forming the cover rubber, is preferably 10 parts by mass or more, further preferably 13 parts by mass or more, even more preferably 16 parts by mass or more, even more preferably 19 parts by mass or more, and particularly preferably 22 parts by mass or more. Furthermore, from the perspective of heat suppression, it is preferably 50 parts by mass or less, further preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

[0147] From the perspective of the effects of the present invention, the content of recovered carbon black, when incorporated into the rubber composition forming the top layer, is preferably 1 part or more per 100 parts by mass of the rubber component, more preferably 3 parts or more, still more preferably 5 parts or more, and particularly preferably 7 parts or more. Furthermore, from the perspective of suppressing heat generation, it is preferably 50 parts or less, more preferably 45 parts or less, still more preferably 40 parts or less, and particularly preferably 35 parts or less.

[0148] From the perspective of reinforcing properties, the carbon black content, based on 100 parts by mass of the rubber component of the rubber composition forming the rubber cover layer, is preferably 1 part by mass or more, further preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, and particularly preferably 10 parts by mass or more. Furthermore, from the perspective of heat suppression, it is preferably 35 parts by mass or less, further preferably 30 parts by mass or less, even more preferably 27 parts by mass or less, even more preferably 23 parts by mass or less, and particularly preferably 20 parts by mass or less. (Other fillers)

[0149] Fillers other than silicon dioxide and carbon black are not particularly restricted, and those commonly used in the tire industry, such as aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, magnesium sulfate, talc, clay, biochar (BIOCHAR), and the like, are permitted. These other fillers can be used alone, or two or more of them can be used in combination.

[0150] From the perspective of the effects of the present invention, the total filler content based on 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, and particularly preferably 35 parts by mass or more. Furthermore, from the perspective of suppressing heat generation, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, and particularly preferably 45 parts by mass or less.

[0151] The ratio of silicon dioxide content to total silicon dioxide and carbon black content in the rubber composition forming the top layer is preferably 5 wt% or more, more preferably 10 wt% or more, even more preferably 15 wt% or more, even more preferably 20 wt% or more, and particularly preferably 25 wt% or more. Furthermore, the ratio of silicon dioxide content to total silicon dioxide and carbon black content in the rubber composition forming the top layer is preferably 75 wt% or less, more preferably 65 wt% or less, even more preferably 55 wt% or less, and particularly preferably 45 wt% or less.

[0152] The ratio of silicon dioxide content to total silicon dioxide and carbon black content in the rubber composition forming the rubber surface layer is preferably 20 wt% or more, more preferably 25 wt% or more, still more preferably 30 wt% or more, and particularly preferably 33 wt% or more. Furthermore, the ratio of silicon dioxide content to total silicon dioxide and carbon black content in the rubber composition forming the rubber surface layer is preferably 99 wt% or less, more preferably 90 wt% or less, still more preferably 80 wt% or less, and particularly preferably 70 wt% or less. (Silane coupling agent)

[0153] Silicon dioxide is preferably used in combination with a silane coupling agent. The silane coupling agent is not particularly restricted, and any silane coupling agent conventionally used in the tire industry in combination with silicon dioxide may be used. Examples include, for instance, mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane; sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl)disulfide and bis(3-triethoxysilylpropyl)tetrasulfide; and thioester-based silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, and 3-octanoylthio-1-propyltrimethoxysilane. Vinyl-based silane coupling agents, such as vinyltriethoxysilane and vinyltrimethoxysilane;Silane coupling agents of the amino type, such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycydoxy-based silane coupling agents, such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents, such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; chlorine-based silane coupling agents, such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane; and the like. Sulfide-based and / or mercapto-based silane coupling agents are preferred. For example, those commercially available from Momentive Performance Materials, etc., may be used as silane coupling agents. These silane coupling agents may be used individually, or two or more may be used in combination.

[0154] The content of silane coupling agents, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, more preferably 2.0 parts by mass or more, and particularly preferably 4.0 parts by mass or more, from the perspective of enhancing the dispersibility of silicon dioxide. Furthermore, from the perspective of preventing deterioration of abrasion resistance, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and more preferably 12 parts by mass or less. <Wärmehärtbares Harz>

[0155] The rubber composition forming the top layer preferably includes a thermosetting resin. Here, the term "thermosetting resin" refers to a resin that is polymerized by heating to form a polymer network structure and is then cured in such a way that the polymerization is irreversible.

[0156] The thermosetting resin is not particularly restricted; examples include, for instance, a resorcinol resin, a modified resorcinol resin, a cresol resin, a modified cresol resin, a phenolic resin, a modified phenolic resin, and the like. These thermosetting resins can be used individually, or two or more can be used in combination. By combining these thermosetting resins, adhesion to a cord, elongation at break, and complex modulus of elasticity can be improved. Among these, a resorcinol resin, a modified resorcinol resin, and a modified cresol resin are preferred, and a modified resorcinol resin is further preferred.

[0157] Examples of resorcinol resin include, for example, a resorcinol-formaldehyde condensate. Examples of modified resorcinol resin include, for example, those in which part of a repeating unit of the resorcinol resin is alkylated.

[0158] Examples of cresol resin include, for instance, a cresol-formaldehyde condensate. Examples of modified cresol resin include, for instance, those in which a methyl group at the end of the cresol resin is modified to a hydroxyl group, and those in which part of a repeating unit of the cresol resin is alkylated.

[0159] Examples of phenolic resins include those obtained by reacting phenol with aldehydes, such as formaldehyde, acetaldehyde, furfural, and the like, with an acid or alkali catalyst. Those obtained by reacting with an acid catalyst (such as a novolac-type phenolic resin) are preferred. Furthermore, examples of modified phenolic resins include a resin obtained by modifying the phenolic resin with cashew nut oil, tall oil, linseed oil, various animal and vegetable oils, an unsaturated fatty acid, rosin, an alkylbenzene resin, aniline, melamine, and the like.

[0160] From the perspectives of adhesion and durability, the content of a thermosetting resin, when incorporated into the rubber composition forming the top layer, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, based on 100 parts by mass of the rubber component, with regard to adhesion and durability. Furthermore, from the perspectives of suppressing the adhesive reaction during vulcanization and preventing a decrease in durability after hygrothermal degradation, it is preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 4.5 parts by mass or less, and particularly preferably 4.0 parts by mass or less. <Härtungsmittel>

[0161] The rubber composition forming the topcoat preferably comprises a curing agent for hardening the thermosetting resin. The curing agent is not particularly restricted; examples include hexamethoxymethylmelamine (HMMM), a modified etherified methylolmelamine resin, hexamethylenetetramine (HMT), pentakis(methoxymethyl)methylolmelamine, tetrakis(methoxymethyl)dimethylolmelamine, and the like. A modified etherified methylolmelamine resin is preferred. These curing agents can be used individually, or two or more can be used in combination.

[0162] From the perspective of the effects of the present invention, the content of a hardening agent, when it is present in the rubber composition forming the top layer, is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 0.7 parts by mass or more. Furthermore, the content is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and even more preferably 2.0 parts by mass or less. <kobaltverbindung>

[0163] The rubber composition forming the cover rubber preferably comprises a cobalt compound. When the rubber composition includes a cobalt compound, the adhesive strength between the steel cord and the cover rubber can be increased, resulting in a tire with excellent durability. Examples of the cobalt compound include, for instance, cobalt alone, cobalt chloride, a cobalt compound with an organic acid, a cobalt compound with an inorganic acid, and the like. A cobalt compound with an organic acid is preferred. These cobalt compounds can be used individually, or two or more can be used in combination.

[0164] The cobalt with organic acid is suitable for promoting adhesion between the clad layer of the steel cord and the rubber composition and for preventing leaching of cladding components into the rubber composition during hygroscopic thermal deterioration. The number of carbon atoms of the organic acid forming the cobalt with organic acid is preferably 12 or more and 24 or less, and more preferably 14 or more and 22 or less. Specific examples of a cobalt salt of an organic acid include, for example, cobalt stearate, cobalt naphthenate, cobalt neodecanoate, cobalt trosinate, cobalt versarate, cobalt tallate, cobalt oleate, cobalt linoleate, cobalt linolenate, cobalt palmitate, and the like. Furthermore, cobalt with organic acid can be a compound salt in which part of the organic acid is replaced by boric acid (for example, cobalt boron-3-neodecanoate).

[0165] Examples of cobalt with inorganic acid include, for example, cobalt sulfate, cobalt nitrate, cobalt phosphate, cobalt chromate, and the like.

[0166] From the perspective of adhesion, the content of a cobalt compound, when incorporated into the rubber composition forming the top layer, is preferably 0.1 parts by mass or more per 100 parts by mass of the rubber component, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more. Furthermore, the content is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and even more preferably 1.5 parts by mass or less. <Andere Verbindungsmittel>

[0167] The rubber composition according to the present embodiment may suitably comprise bonding agents that are conventionally and generally used in the tire industry, for example a plasticizer, a vulcanized rubber particle (rubber powder), an antioxidant, wax, processing aids, stearic acid, zinc oxide, a vulcanizing agent, a vulcanization accelerator and the like, in addition to the components described above.

[0168] In this description, a "plasticizer" is a material that imparts plasticity to a rubber component and encompasses both plasticizers that are liquid at normal temperature (25°C) and those that are solid at normal temperature (25°C). Examples of plasticizers include resin components, oils, liquid polymers, ester-based plasticizers, and the like. These plasticizers can be derived from petroleum, biomass, or naphtha, which may be recycled from a rubber or non-rubber product.Furthermore, a low molecular weight hydrocarbon component obtained by pyrolysis and extraction from a used tire or a product comprising various components can be used as a plasticizer. These plasticizers can be used alone, or two or more can be used in combination. (resin component)

[0169] The resin component is not particularly restricted, and any resin component commonly used in the tire industry can be used. Examples include adhesive resins such as C9-based, C5-based, C5 / C9-based, dicyclopentadiene-based, aromatic vinyl-based, terpene-based, rosin-based, phenol-based, and the like. These resin components can be used individually, or two or more can be used in combination.The rubber composition according to the present embodiment preferably comprises one or more resin components selected from the group consisting of a terpene-based resin, a dicyclopentadiene-based resin and an aromatic vinyl-based resin, and further preferably comprises a resin component comprising dicyclopentadiene, styrene and indene as monomer components.

[0170] The term "C9-based resin" refers to a resin obtained by polymerizing C9 fractions. This can be a resin obtained by polymerizing a C9 fraction alone, or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. Furthermore, these resins may be hydrogenated or modified. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumaron, indene, methylindene, dicyclopentadiene, and the like. These C9-based resins can be used alone, or two or more of them can be used in combination.

[0171] The term "C5-based resin" refers to a resin obtained by polymerizing C5 fractions, and can be one obtained by hydrogenating or modifying them. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentene, isopentane, neopentane, pentadiene, and the like. These C5-based resins can be used individually, or two or more of them can be used in combination.

[0172] C5 / C9-based resin refers to a resin obtained by copolymerizing the C5 and C9 fractions, and can also be one obtained by hydrogenation or modification thereof. For example, suitable C5 / C9-based petroleum resins include those commercially available from Tosoh Corporation, Zibo Luhua Hongjin New Material Group Co., Ltd. These C5 / C9-based resins can be used individually, or two or more can be used in combination.

[0173] The term "dicyclopentadiene-based resin" refers to a resin comprising cyclopentadiene (CPD) or dicyclopentadiene (DCPD), and may be one obtained by hydrogenation or modification thereof. Examples of dicyclopentadiene-based resins include, for instance, a DCPD / C9 resin comprising dicyclopentadiene and the C9 fraction as monomer components (the DCPD / C9 resin may be one obtained by hydrogenation or modification thereof), and the like, preferably a DCPD / C9 resin comprising dicyclopentadiene, styrene, and indene as monomer components. Examples of dicyclopentadiene-based resins include those commercially available from Exxon Mobil Corporation, ENEOS Corporation, Zeon Corporation, Maruzen Petrochemical Co., Ltd., etc. These dicyclopentadiene-based resins may be used individually, or two or more may be used in combination.

[0174] The term "aromatic vinyl-based resin" refers to a resin that incorporates an aromatic vinyl compound, such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, and the like, as the monomer component with the highest concentration, and may be one obtained by hydrogenation or modification thereof. A homopolymer of α-methylstyrene or styrene, or a copolymer of α-methylstyrene and styrene, is preferred as the aromatic vinyl-based resin, and a copolymer of α-methylstyrene and styrene is further preferred due to its economic efficiency, ease of processing, and excellent heat generation properties. Examples of aromatic vinyl-based resins that may be used include those commercially available from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc.These aromatic vinyl-based resins can be used alone, or two or more of them can be used in combination.

[0175] The term "terpene-based resin" refers to a resin that incorporates a terpene compound, such as α-pinene, β-pinene, limonene, dipentene, and the like, as a monomer component, and may be one obtained by hydrogenation or modification thereof. Specific examples of terpene-based resin include, for example, a polyterpene resin, which incorporates only one or more of the terpene compounds as monomer components; an aromatically modified terpene resin, which incorporates the terpene compound and an aromatic compound as monomer components; a terpenophenolic resin, which incorporates the terpene compound and a phenol-based compound as monomer components; and the like. Examples of aromatic compounds used as monomer components for aromatically modified terpene resins include, for example, styrene, α-methylstyrene, vinyltoluene, divinyltoluene, and the like.Examples of phenol-based compounds used as monomers for terpene phenol resins include phenol, bisphenol A, cresol, xylenol, and the like. These terpene-based resins can be used individually, or two or more can be used in combination.

[0176] The term "rosin-based resin" refers to a resin comprising a rosin acid compound, such as abietic acid, neoabietic acid, palustric acid, isopimaric acid, and the like, and may be one obtained by hydrogenation or modification thereof. Examples of rosin-based resin include, but are not limited to: natural resin rosin; and rosin-modified resin obtained by modifying it through hydrogenation, disproportionation, dimerization, esterification, or the like; etc. These rosin-based resins may be used alone, or two or more of them may be used in combination.

[0177] The term "phenol-based resin" refers to a resin that incorporates a phenolic compound, such as phenol, cresol, and the like, as the predominant monomer component, and may be one obtained by hydrogenation or modification thereof. Examples of phenol-based resins include, but are not limited to, phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, oil-modified phenol-formaldehyde resins, and the like. These phenol-based resins can be used individually, or two or more of them can be used in combination.

[0178] The softening point of the adhesive resin is preferably 35 °C or higher, more preferably 50 °C or higher, and even more preferably 65 °C or higher. Furthermore, for the sake of processability and improved dispersibility of a rubber component with a filler, it is preferably 150 °C or lower, more preferably 140 °C or lower, and even more preferably 130 °C or lower. The softening point of the adhesive resin is also measured using the method described above.

[0179] When incorporated into the rubber composition forming the rubber top layer, the adhesive resin content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. Furthermore, from the perspective of heat suppression, it is preferably less than 40 parts by mass, more preferably less than 30 parts by mass, even more preferably less than 20 parts by mass, and particularly preferably 15 parts by mass or less. Additionally, when incorporated into the rubber composition forming the top layer, the adhesive resin content is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, and even more preferably less than 10 parts by mass, but this is not a particularly restrictive limitation.

[0180] Examples of oil include process oil, vegetable oil, animal oil, and the like. Examples of process oil include paraffin-based (mineral oil), naphthene-based, aromatic-based, and the like. Specific examples of process oil include Mild Extract Solvate (MES), Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Treated Residual Aromatic Extract (TRAE), Residual Aromatic Extract (RAE), and the like. Furthermore, as an environmental measure, a process oil with a low polycyclic aromatic compound (PCA) content may be used. Examples of low PCA process oils include MES, TDAE, heavy naphthenic oil, and the like.Furthermore, from an environmental impact assessment perspective, those obtained by cleaning waste oil after use in a rubber mixer or engine, or waste cooking oil used in a restaurant, can be used.

[0181] Examples of vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, Japan wax, and the like. Furthermore, examples of vegetable oils include refined oils, which are obtained by refining the oils described above (cooking oils, etc.).), a transesterified oil obtained by transesterifying the oil described above, a hydrogenated oil obtained by hydrogenating the oil described above, a thermally polymerized oil obtained by thermally polymerizing the oil described above, an oxidized polymerized oil obtained by oxidizing the oil described above, a used cooking oil obtained by restoring what was previously used as an edible oil, etc., and the like. Furthermore, the vegetable oil may be liquid or solid at normal temperature (25°C). The vegetable oil may be used alone, or two or more may be used in combination.

[0182] The vegetable oil preferably comprises acylglycerol and further preferably triacylglycerol. In this description, acylglycerol also refers to a compound in which a hydroxyl group of glycerol and a fatty acid are ester-bound. Acylglycerol is not particularly restricted and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a multimer that is a trimer or higher. Additionally, acylglycerol that is a dimer or higher may be obtained by thermal polymerization, oxidative polymerization, or the like. Finally, acylglycerol may be liquid or solid at normal temperature (25 °C).

[0183] One method of verifying whether the rubber composition includes the acylglycerol described above can be carried out, for example, by 1 H-NMR measurements can be performed below, but are not particularly limited to this. In particular, a rubber composition comprising triacylglycerol is immersed in heavy chloroform at room temperature (25 °C) for 24 hours and removed to 1 When measuring ¹H NMR at room temperature, and if a signal from tetramethylsilane (TMS) is defined as 0.00 ppm, signals close to 5.26 ppm, 4.28 ppm, and 4.15 ppm are observed, with the signals assumed to be derived from hydrogen atoms bonded to carbon atoms adjacent to oxygen atoms of an ester group. Furthermore, "close" in this paragraph refers to a range of ±0.10 ppm.

[0184] The fatty acid described above is not particularly restricted and can be either an unsaturated or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids, such as oleic acid, and the like, and polyunsaturated fatty acids, such as linoleic acid, linolenic acid, and the like. Furthermore, examples of saturated fatty acids include butyric acid, lauric acid, and the like.

[0185] The desired fatty acid is one with few double bonds, meaning a saturated or monounsaturated fatty acid, and oleic acid is preferred. A vegetable oil containing such a fatty acid can be, for example, a saturated or monounsaturated fatty acid, or it can be a vegetable oil modified by transesterification or similar processes. Furthermore, to produce a vegetable oil containing such a fatty acid, a plant can be improved through selective breeding, gene combination, or similar methods.

[0186] For example, vegetable oils that are commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo KK, ENEOS Corporation, Olisoy, H&R Group, Hokoku Corporation, Fuji Kosan Co., Ltd., The Nisshin OilliO Group, Ltd., etc., can be used.

[0187] Examples of animal oil include fish oil, beef tallow, oleyl alcohol derived from it, or the like.

[0188] When combined, the oil content, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, from the perspective of the effects of the present invention. Furthermore, the content is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, even more preferably less than 15 parts by mass, and particularly preferably 10 parts by mass or less.

[0189] The liquid polymer is not particularly restricted as long as it is a polymer in a liquid state at normal temperature (25 °C), and examples include, for instance, a liquid butadiene polymer (liquid BR), a liquid isoprene rubber polymer (liquid IR), a liquid styrene-butadiene copolymer (liquid SBR), a liquid styrene-isoprene rubber copolymer (liquid SIR), a polymer comprising myrcene or farnesene, and the like. These liquid polymers can be used alone, or two or more of them can be used in combination.

[0190] The liquid polymer content, when combined, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the content is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, and even more preferably 10 parts by mass or less.

[0191] Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), bis(2-ethylhexyl) azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), and the like. Ester-based plasticizers can be used alone, or two or more can be used in combination.

[0192] From the perspective of the effects of the present invention, the plasticizer content, when combined, is based on 100 parts by mass of the rubber component (a total quantity of several plasticizers when used in combination), preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, the content is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 35 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0193] Examples of the antioxidant include, but are not limited to, a naphthylamine-based antioxidant such as phenyl-α-naphthylamine and the like; a diphenylamine-based antioxidant such as an octylated diphenylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine and the like; an antioxidant based on p-phenylenediamine, such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD) and the like; an antioxidant based on quinoline, such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline and the like;A monophenol-based antioxidant, such as 2,6-di-t-butyl-4-methylphenol, a styrenized phenol, and the like; and bis-, tris-, and polyphenol-based antioxidants, such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane and the like. Among these, p-phenylenediamine-based and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are further preferred. Commercially available products may include, for example, those manufactured by Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexsys, etc. These antioxidants can be used alone, or two or more of them can be used in combination.

[0194] The content of the antioxidant, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, with regard to the ozone crack resistance of a rubber. Furthermore, with regard to abrasion resistance, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0195] The type of wax is not particularly restricted, and any wax commonly used in the tire industry may be suitable. Examples of wax include, for instance, petroleum-based wax, mineral-based wax, synthetic wax, plant-derived wax, and the like. Among these, petroleum-based and plant-derived waxes are preferred, and petroleum-based wax is further preferred. Examples of plant-derived waxes include, for instance, rice wax, carnauba wax, candelilla wax, and the like. Examples of petroleum-based waxes include, for instance, paraffin wax, microcrystalline wax, specially selected waxes thereof, and the like. Among these, paraffin wax is preferred. Furthermore, according to the present embodiment, the wax should not contain stearic acid.Suitable waxes include those commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt BV, etc. These waxes can be used individually, or two or more can be used in combination.

[0196] The wax content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more and more preferably 0.8 parts by mass or more, from the perspective of improving the weather resistance of the rubber. Furthermore, from the perspective of preventing the whitening of a tire due to blooming, it is preferably 10 parts by mass or less and more preferably 5.0 parts by mass or less.

[0197] Examples of processing aids include, for example, a fatty acid metal salt, a fatty acid amide, an amide ester, a silicon dioxide surface activator, a fatty acid ester, a mixture of a fatty acid metal salt and an amide ester, a mixture of a fatty acid metal salt and a fatty acid amide, and the like. Processing aids that can be used include those commercially available from Schill+Seilacher GmbH, Performance Additives, etc. These processing aids can be used individually, or two or more of them can be used in combination.

[0198] The stearic acid content, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, from the point of view of processability. Furthermore, from the point of view of vulcanization rate, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0199] From the perspective of the effects of the present invention, the zinc oxide content, when combined in the rubber composition forming the top layer, is preferably 1.0 parts by mass or more, more preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, and particularly preferably 4.0 parts by mass or more, based on 100 parts by mass of the rubber component. Furthermore, from the perspective of abrasion resistance, it is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and more preferably 9 parts by mass or less.

[0200] From a processability standpoint, the zinc oxide content, when incorporated into the rubber composition forming the rubber top layer, is preferably 0.5 parts by mass or more, and more preferably 1.0 parts by mass or more, based on 100 parts by mass of the rubber component. Furthermore, from an abrasion resistance standpoint, it is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0201] Sulfur is suitable for use as a vulcanizing agent. Suitable forms of sulfur include powdered sulfur, oil-processing sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and the like.

[0202] From the perspective of the effects of the present invention, the sulfur content, when incorporated into the rubber composition forming the top layer, is preferably 1.0 parts by mass or more, more preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, more preferably 4.0 parts by mass or more, and most preferably 5.0 parts by mass or more, based on 100 parts by mass of the rubber component. Furthermore, from the perspective of preventing deterioration, it is preferably 10.0 parts by mass or less, more preferably 9.0 parts by mass or less, and more preferably 8.0 parts by mass or less. Additionally, when an oil-containing sulfur is used as a crosslinking agent, the content of the vulcanizing agent is said to be the total content of pure sulfur contained in the oil-containing sulfur.

[0203] The sulfur content, when compounded, in the rubber composition forming the rubber top layer, based on 100 parts by mass of the rubber component, is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and still more preferably 0.5 parts by mass or more, to ensure a sufficient vulcanization reaction. Furthermore, to prevent deterioration, it is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and still more preferably 3.0 parts by mass or less.

[0204] As a vulcanizing agent other than sulfur, a known organic crosslinking agent can also be used. The organic crosslinking agent is not particularly restricted as long as it can form crosslinked chains other than polysulfide bonds. Examples include, for instance, an alkylphenol-sulfur chloride condensate, sodium hexamethylene 1,6-bisthiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, dicumyl peroxide, and the like. Sodium hexamethylene 1,6-bisthiosulfate dihydrate is preferred. These organic crosslinking agents can include those commercially available from Taoka Chemical Co., Ltd., LANXESS, Flexsys, etc.

[0205] The content of a vulcanizing agent other than sulfur (preferably sodium hexamethylene-1,6-bisthiosulfate dihydrate), when combined in the rubber composition forming the top layer, is, from the perspective of the effects of the present invention, preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, based on 100 parts by mass of the rubber component. Alternatively, the content is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0206] Examples of vulcanization accelerators include, but are not limited to, sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiourea-based vulcanization accelerators, dithiocarbamic acid-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, imidazoline-based vulcanization accelerators, xanthate-based vulcanization accelerators, caprolactam disulfide, and the like. These vulcanization accelerators can be used alone, or two or more of them can be used in combination.Among these, one or more vulcanization accelerators selected from the group consisting of a sulfenamide-based vulcanization accelerator, a thiazole-based vulcanization accelerator, and a guanidine-based vulcanization accelerator are preferred, given that suitable effects can be obtained more appropriately.

[0207] Examples of sulfenamide-based vulcanization accelerators include, for example, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), and the like.

[0208] Examples of thiazole-based vulcanization accelerators include, for example, 2-mercaptobenzothiazole (MBT) or a salt thereof, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, and the like. Among these, MBTS and MBT are preferred, and MBTS is further preferred.

[0209] Examples of guanidine-based vulcanization accelerators include, for example, 1,3-diphenylguanidine (DPG), 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatechol borate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, 1,3-di-o-cumenyl-2-propionylguanidine, and the like. DPG is the preferred compound. However, from the point of view of the effects of the present invention, the content of the guanidine-based vulcanization accelerator in the rubber composition forming the top rubber, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.1 parts by mass or less, and it is particularly preferred that the rubber composition does not include a guanidine-based vulcanization accelerator.

[0210] The content of a vulcanization accelerator, when combined, based on 100 parts by mass of the rubber component, is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, to ensure a sufficient vulcanization rate. Furthermore, the content of the vulcanization accelerator, to suppress blooming, is preferably 10 parts by mass or less, and more preferably 5.0 parts by mass or less.

[0211] In the present description, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. One method for obtaining these materials from carbon dioxide is to convert carbon dioxide directly, or to convert methane, which is obtained from carbon dioxide through a methanation step. [Production of rubber compound and tires]

[0212] The rubber composition according to the present embodiment can be produced by a known method. It can be produced, for example, by kneading each of the components described above using a rubber kneading device, such as an open roller, a closed-type kneader (Bunbury mixer, kneader, etc.), and the like.

[0213] The kneading step includes, for example, a basic kneading step involving the kneading of bonding agents and additives other than vulcanizing agents and vulcanization accelerators, and a final kneading step (F-kneading) involving the addition of vulcanizing agents and vulcanization accelerators to the kneaded product obtained by the basic kneading step, and the kneading of this product. Furthermore, the basic kneading step can be subdivided into several steps if desired.

[0214] A kneading condition is not particularly restricted. Examples of kneading include, for instance, a process of kneading at a discharge temperature of 150 to 170 °C for 3 to 10 minutes for the basic kneading step, and a process of kneading at 70 to 110 °C for 1 to 5 minutes for the final kneading step.

[0215] The tire according to the present embodiment, comprising a top rubber and a rubber cover layer made of the rubber composition described above, can each be produced by a conventional process using appropriate rubber compositions. That is, a steel cord is covered with an unvulcanized rubber composition corresponding to the top rubber to obtain a steel cord-rubber composite.The tire can then be produced by extruding the unvulcanized rubber compound, corresponding to the rubber liner, into a liner mold using an extruder equipped with a die of a predetermined shape. This mold, along with other tire components, is then placed on a tire forming machine and shaped using a standard procedure to form an unvulcanized tire. This unvulcanized tire is then heated and pressurized in a vulcanizing machine. Vulcanization conditions are not particularly restricted. Examples of vulcanization include, for instance, a process of vulcanizing at 150 to 200 °C for 10 to 30 minutes. <anwendung>

[0216] The tire according to the present embodiment can be a universal tire, such as a tire for a passenger car, a tire for a truck / bus, a motorcycle tire, and the like, or it can be a racing tire. Furthermore, a tire for a passenger car is defined as a tire mounted on a four-wheeled vehicle and refers to one with a maximum load capacity of 1000 kg or less. In addition, the tire according to the present embodiment can be used as an all-season tire, a summer tire, or a winter tire, such as a studless tire, and the like. EXAMPLES

[0217] Examples considered preferred for implementation (examples) are shown below, but the scope of protection of the present invention is not limited to examples. Considering tires comprising a steel cord covered with a rubber top layer obtained according to the compound in Table 1 and a rubber top layer obtained according to the compound in Table 2, results calculated using various chemicals shown below, based on evaluation methods described below, are shown in Tables 3 to 7.

[0218] Various chemicals used in examples and comparisons are shown collectively below. NR: TSR20 BR: UBEPOL BR (registered trademark) 150B, manufactured by Ube Industries, Ltd. (unmodified BR, cis content: 97 wt%, Mw: 440,000) SBR: SBR1502, manufactured by JSR Corporation (unmodified E-SBR, styrene content: 23.5 wt%, vinyl content: 18 mol%, Mw: 420,000) Soot 1: Show Black N330, manufactured by Cabot Japan KK (N2SA: 75 m 2 / g, average primary particle size: 30 nm) Soot 2: Show Black N220, manufactured by Cabot Japan KK (N2SA: 115 m 2 / g, average primary particle size: 22 nm) Carbon black 3: SS550, manufactured by Strebl Green Carbon Pte Ltd. (recovered carbon black obtained from a tire pyrolysis process) Silicon dioxide: ULTRASIL VN3, manufactured by Evonik Degussa GmbH (N2SA: 175 m 2 / G) Silane coupling agent: Si266, manufactured by Evonik Degussa GmbH (Bis(3-triethoxysilylpropyl)disulfide) Thermosetting resin: SUMILITERESIN PR-12686E, manufactured by Sumitomo Bakelite Co., Ltd. (phenolic resin modified with cashew nut oil, softening point: 100 °C) Curing agent: SUMIKANOL 507AP, manufactured by Taoka Chemical Co., Ltd. (modified etherified methylol melamine resin) Oil: Diana Process NH-70S, manufactured by Idemitsu Kosan Co., Ltd. (aromatic-based process oil) Adhesive resin 1: SYLVATARAXX4150, manufactured by Kraton Corporation (polyterpene resin, softening point: 115 °C) Adhesive resin 2: Oppera PR-395, manufactured by Exxon Mobil Corporation (hydrogenated DCPD / C9 resin, softening point: 118 °C) Zinc oxide: Zinc oxide No. 1, manufactured by Mitsui Mining & Smelting Co., Ltd. Antioxidant 1: Nocrac 6C, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine) Antioxidant 2: Nocrac FR, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (2,2,4-Trimethyl-1,2-dihydroquinoline polymer) Cobalt compound: Cost-F, manufactured by DIC Corporation (cobalt stearate) Stearic acid: Stearic acid “CAMELLIA”, manufactured by NOF CORPORATION Wax: OZOACE 0355, manufactured by Nippon Seiro Co., Ltd. Vulcanizing agent 1: M95, manufactured by Nippon Kanryu Industry Co., Ltd. (insoluble sulfur) Vulcanizing agent 2: DURALINK HTS, manufactured by Flexsys (sodium hexamethylene-1,6-bisthiosulfate dihydrate) Vulcanizing agent 3: Powdered sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd. (5% oil-containing sulfur powder) Vulcanization accelerator 1: Nocceler DZ, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N,N-Dicyclohexyl-2-benzothiazolylsulfenamide (DCBS)) Vulcanization accelerator 2: Nocceler CZ, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-Cyclohexyl-2-benzothiazolylsulfenamide (CBS)) Vulcanization accelerator 3: Nocceler D, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (1,3-Diphenylguanidine (DPG)) (Examples and comparisons)

[0219] According to the compound formulations shown in Tables 1 and 2, all chemicals except sulfur and vulcanization accelerator are kneaded using a closed 1.7-liter Banbury mixer for 5 minutes until a discharge temperature of 160 °C is reached to obtain a kneaded product. Next, using an open twin-screw mixer, vulcanizing agent and vulcanization accelerator are added to the kneaded product, and the mixture is kneaded for 4 minutes until the temperature reaches 105 °C to obtain an unvulcanized rubber composition. The resulting unvulcanized rubber composition, shown in Table 1, is used to coat a steel cord (filament diameter: 0.30 mm) to create a steel cord-rubber composite.The unvulcanized rubber composition listed in Table 2 is then extruded into a rubber cover layer mold using an extruder equipped with a die of a predetermined shape. This mold, along with other tire elements, is placed on a tire forming machine to produce an unvulcanized tire, which is then vulcanized at 170 °C to create each of the test tires described in Tables 3 to 7. Here, a binary-clad steel cord has a plating layer with an average thickness of 0.24 µm and a composition of 63 wt% Cu and 37 wt% Zn, while a ternary-clad steel cord has a plating layer with an average thickness of 0.19 µm and a composition of 68 wt% Cu, 28 wt% Zn, and 4 wt% Co.Furthermore, in steel cord configurations in tables, “1 × 2 40e” means that there are 40 steel cords with a structure of 1 × 2 per 50 mm width in a direction perpendicular to a longitudinal direction of a steel cord (40 ends), and “1 × 1 80e” means that there are 80 monofilament steel cords with a structure of 1 × 1 per 50 mm width in the direction perpendicular to the longitudinal direction of the steel cord (80 ends). <Messung von 70 °C-tanδ1 und 70 °C-E*1>

[0220] For each vulcanized rubber test piece produced by cutting out a 20 mm long × 4 mm wide × 1 mm thick piece from a cover rubber covering a steel cord of each test tire, such that one tire circumferential direction becomes a long side and one tire radial direction becomes a thickness direction, a loss tangent tanδ and a complex modulus of elasticity E* are measured using a dynamic viscoelasticity measuring device (EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under a temperature of 70 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of 1%, and a strain mode. <Messung von 30 °C-tanδ2 und 0 °C-tanδ2>

[0221] For each vulcanized rubber test piece, produced by cutting a 20 mm long × 4 mm wide × 1 mm thick section from the interior of a rubber cover layer of a tread section of each test tire, such that one tire circumference direction becomes a long side and one tire radial direction becomes a thickness direction, a loss tangent (tanδ) is measured using a dynamic viscoelasticity measuring device (EPLEXOR series, manufactured by gabo Systemtechnik GmbH) under conditions of a temperature of 30 °C, a frequency of 10 Hz, an initial strain of 5%, a dynamic strain of ±1%, and a specific strain mode. Additionally, a loss tangent (tanδ) is measured under conditions of a temperature of 0 °C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±2.5%, and a specific strain mode. <Schältest>

[0222] A belt layer comprising a tire equator section is cut into a sample 25 mm wide along the tire's axial direction. The sample is then incubated for one week in an oven at 80 °C and 90% relative humidity to undergo hygrothermal degradation. The resulting sample is peeled from one end along a space between belt layers at a rate of 50 mm / min using a peel tester, and the peel strength at this time is measured. The results are then expressed as "durability" using an index, where the peel strength of each of the reference examples (reference example 4 in Table 3, reference example 8 in Table 4, reference example 13 in Table 5, reference example 17 in Table 6, and reference example 21 in Table 7) is 100. Table 1 Cover rubber A1 A2 A3 A4 A5 A6 A7 A8 Composite quantity (mass parts) NR 100 100 100 100 100 100 100 100 Soot 1 60 55 30 40 50 25 20 40 Soot 3 - - - - - - 10 - silicon dioxide - - - - - 10 8 - thermosetting resin 7,0 5,0 3,0 3,0 3,0 2,0 3,0 8,0 hardening agents 2,8 2,0 1,2 1,2 1,2 0,8 1,2 3,2 Öl 5,0 5,0 - - - - - - Cobalt compound 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 zinc oxide 6,0 6,0 6,0 6,0 6,0 6,0 6,0 6,0 Antioxidant 1 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Vulcanizing agent 1 7,0 7,0 7,0 7,0 7,0 7,0 7,0 7,0 Vulcanizing agent 2 2,0 2,0 2,0 2,0 2,0 2,0 2,0 4,0 Vulcanization accelerator 1 2,0 1,0 3,5 3,5 3,5 3,5 3,5 4,0 Vulcanization accelerator 2 - - - - - - - 4,5 70 °CE*1 (MPa) 18,5 12,8 6,2 9,5 13,7 6,2 5,8 20,1 70 °C-tanδ1 0,115 0,112 0,030 0,044 0, 061 0,033 0,032 0,030 Table 2 rubber top layer B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 Composite quantity (mass parts) NR 15 15 15 15 - - - 40 40 40 BR 35 35 35 35 35 35 35 60 60 60 SBR 50 50 50 50 65 65 65 - - - Soot 2 25 20 20 15 25 20 15 25 20 15 silicon dioxide 35 35 12 12 35 12 12 35 12 12 Silane coupling agent 2,5 2,5 1,0 1,0 2,5 1,0 1,0 2,5 1,0 1,0 Öl 2 10 10 10 - 10 10 - 10 10 - Adhesive resin 1 - - - 8 - - 8 - - 10 Adhesive resin 2 - - - - - - - - - 5 zinc oxide 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 Antioxidant 1 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Antioxidants 2 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Stearic acid 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 wax 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 Vulcanizing agent 3 1,5 1,5 1,5 2,5 1,5 1,5 2,5 1,5 2,5 2,5 Vulcanization accelerator 2 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 2,0 Vulcanization accelerator 3 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 Total styrene amount S (mass %) 11,8 11,8 11,8 11,8 15,3 15,3 15,3 0 0 0 0 °C-tanδ2 0,329 0,315 0,287 0,324 0,329 0,290 0,331 0,259 0,222 0,297 30 °C-tanδ2 0,226 0,204 0, 146 0,128 0,225 0,143 0,125 0,198 0,124 0,120 0 °C-tanδ2 / 30 °C-tanδ2 1,46 1,54 1,97 2,53 1,46 2,03 2,65 1,31 1,79 2,48 Table 3 Example Comparative example 1 2 3 4 5 6 7 8 1 2 3 4 Cover rubber A5 A6 A7 A7 A7 A7 A7 A7 A1 A8 A2 A1 rubber top layer B1 B1 B1 B2 B3 B4 B4 B4 B1 B1 B1 B3 70 °CE*1(MPa) 13,7 6,2 5,8 5,8 5,8 5,8 5,8 5,8 18,5 20,1 12,8 18,5 70 °C-tanδ1 0,061 0,033 0,032 0,032 0,032 0,032 0,032 0,032 0,115 0,030 0,112 0,115 Total styrene quantity S (mass %) 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11, 8 0 °C tanδ2 0,329 0, 329 0,329 0,315 0,287 0,324 0,324 0,324 0,329 0,329 0,329 0,287 30 °C-tanδ2 0,226 0,226 0,226 0,204 0, 146 0,128 0,128 0,128 0,226 0,226 0,226 0,146 0°C-tanδ2 / 30°C-tanδ2 1,46 1,46 1,46 1,54 1,97 2,53 2,53 2,53 1,46 1,46 1,46 1,97 Tire weight G (kg) 17,0 17,0 17,0 17,0 17,0 17,0 17,0 18,5 17,0 17,0 17,0 17,0 Maximum load capacity W L (kg) 1100 1100 1100 1100 1100 1100 1100 1100 1100 1100 1100 1100 G / W L 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0168 0,0155 0,0155 0,0155 0,0155 9,33 × 10 -5 × W L - 70 °C-tanδ1 0,042 0,070 0,071 0,071 0,071 0,071 0,071 0,071 -0,012 0,073 -0,009 -0,012 plating layer Binary Binary Binary Binary Binary Binary Ternary Binary Binary Binary Binary Binary Configuration of steel cord 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 1 1 × 2 1 × 2 1 × 2 1 × 2 40e 40e 40e 40e 40e 40e 40e 80e 40e 40e 40e 40e S (mm 2 ) 0,141 0,141 0,141 0,141 0,141 0,141 0,141 0,071 0,141 0,141 0,141 0,141 S × E 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 Y / (S × E) 0 1,8 1,4 1,4 1,4 1,4 1,4 1,4 0 0 0 0 [Durability] 120 136 149 155 170 182 190 206 81 93 96 100 Table 4 Example Comparative example 9 10 11 12 13 14 15 16 5 6 7 8 Cover rubber A4 A6 A7 A7 A7 A7 A7 A7 A1 A8 A2 A1 rubber top layer B1 B1 B1 B2 B3 B4 B4 B4 B1 B1 B1 B3 70 °CE*1(MPa) 9,5 6,2 5,8 5,8 5,8 5,8 5,8 5,8 18,5 20,1 12,8 18,5 70 °C-tanδ1 0,044 0,033 0,032 0,032 0,032 0,032 0,032 0,032 0,115 0,030 0,112 0,115 Total styrene amount (mass %) 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 0 °C-tanδ2 0,329 0,329 0,329 0,315 0,287 0,324 0,324 0,324 0,329 0,329 0,329 0,287 30 °C-tanδ2 0,226 0,226 0,226 0,204 0,146 0,128 0,128 0,128 0,226 0,226 0,226 0,146 0 °C-tanδ2 / 30 °C-tanδ2 1,46 1,46 1,46 1,54 1, 97 2,53 2,53 2,53 1,46 1,46 1,46 1, 97 Tire weight G (kg) 16,0 16,0 16, 0 16, 0 16,0 16,0 16,0 17,0 16,0 16,0 16, 0 16,0 Maximum load capacity W L (kg) 817 817 817 817 817 817 817 817 817 817 817 817 G / W L 0,0196 0,0196 0,0196 0,0196 0,0196 0,0196 0,0196 0,0208 0,0196 0,0196 0,0196 0,0196 9,33 × 10 -5 ×W L - 70 °C-tanδ1 0,032 0,043 0,044 0,044 0,044 0,044 0,044 0,044 -0,039 0,046 -0,036 -0,039 plating layer Binary Binary Binary Binary Binary Binary Ternary Binary Binary Binary Binary Binary Configuration of steel cord 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 1 1 × 2 1 × 2 1 × 2 1 × 2 40e 40e 40e 40e 40e 40e 40e 80e 40e 40e 40e 40e S (mm 2 ) 0,141 0,141 0,141 0,141 0,141 0,141 0,141 0,071 0,141 0,141 0,141 0,141 S × E 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 Y / (S × E) 0 1,8 1,4 1,4 1,4 1,4 1,4 1,4 0 0 0 0 [Durability] 121 138 152 158 174 186 195 212 80 93 96 100 Table 5 Example 17 18 19 20 21 22 23 24 Cover rubber A3 A6 A7 A7 A7 A7 A7 A7 rubber top layer B1 B1 B1 B2 B3 B4 B4 B4 70 °CE*1 (MPa) 6,2 6,2 5,8 5,8 5,8 5,8 5,8 5,8 70 °C-tanδ1 0,030 0,033 0,032 0,032 0,032 0,032 0,032 0,032 Total styrene amount S (mass %) 11,8 11,8 11,8 11,8 11,8 11,8 11,8 11,8 0 °C-tanδ2 0,329 0,329 0,329 0,315 0,287 0,324 0,324 0,324 30 °C-tanδ2 0,226 0,226 0,226 0,204 0,146 0,128 0,128 0,128 0 °C-tanδ2 / 30 °C-tanδ2 1,46 1,46 1,46 1,54 1,97 2,53 2,53 2,53 Tire weight G (kg) 11,0 11,0 11,0 11,0 11,0 11,0 11,0 11,8 Maximum load capacity W L (kg) 609 609 609 609 609 609 609 609 G / W L 0,0181 0,0181 0,0181 0,0181 0,0181 0,0181 0,0181 0,0194 9,33 × 10 -5 × W L - 70 °C-tanδ1 0,027 0,024 0,025 0,025 0,025 0,025 0,025 0,025 plating layer Binary Binary Binary Binary Binary Binary Ternary Binary Steel cord configuration 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 1 40e 40e 40e 40e 40e 40e 40e 80e S (mm 2 ) 0,141 0,141 0,141 0,141 0,141 0,141 0,141 0,071 S × E 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 Y / (S × E) 0 1, 8 1, 4 1, 4 1, 4 1, 4 1, 4 1, 4 [Durability] 114 130 142 148 162 173 181 196 Comparative example 9 10 11 12 13 Cover rubber A1 A8 A2 A1 A5 rubber top layer B1 B1 B1 B3 B1 70 °CE*1 (MPa) 18,5 20,1 12,8 18,5 13,7 70 °C-tanδ1 0,115 0,030 0,112 0,115 0,061 Total styrene amount S (mass %) 11,8 11,8 11,8 11,8 11,8 0 °C-tanδ2 0,329 0,329 0,329 0,287 0,329 30 °C-tanδ2 0,226 0,226 0,226 0,146 0,226 0 °C-tanδ2 / 30 °C-tanδ2 1,46 1,46 1,46 1,97 1,46 Tire weight G (kg) 11,0 11,0 11,0 11,0 11,0 Maximum load capacity W L (kg) 609 609 609 609 609 G / W L 0,0181 0,0181 0,0181 0,0181 0,0181 9,33 × 10 -5 × W L - 70 °C-tanδ1 -0,058 0,027 -0, 055 -0, 058 -0, 004 plating layer Binary Binary Binary Binary Binary Steel cord configuration 1 × 240e 1 × 240e 1 × 240e 1 × 240e 1 × 240e S (mm 2 ) 0,141 0,141 0,141 0,141 0,141 S × E 5, 6 5, 6 5, 6 5, 6 5, 6 Y / (S × E) 0 0 0 0 0 [Durability] 77 89 91 95 100 Table 6 Example Comparative example 25 26 27 28 29 14 15 16 17 Cover rubber A5 A6 A7 A7 A7 A1 A8 A2 A1 rubber top layer B5 B5 B5 B6 B7 B5 B5 B5 B6 70 °CE*1 (MPa) 13,7 6,2 5,8 5,8 5,8 18,5 20,1 12,8 18,5 70 °C-tanδ1 0,061 0, 033 0,032 0,032 0,032 0,115 0,030 0,112 0,115 Total styrene quantity S (mass %) 15,3 15,3 15,3 15,3 15,3 15,3 15,3 15,3 15,3 0 °C-tanδ2 0,329 0,329 0,329 0,290 0,331 0,329 0,329 0,329 0,290 30 °C-tanδ2 0,225 0,225 0,225 0, 143 0,125 0,225 0,225 0,225 0,143 0 °C-tanδ2 / 30 °C-tanδ2 1,46 1,46 1,46 2,03 2,65 1,46 1,46 1,46 2,03 Tire weight G (kg) 17,0 17,0 17,0 17,0 17,0 17,0 17,0 17,0 17,0 Maximum load capacityW L (kg) 1100 1100 1100 1100 1100 1100 1100 1100 1100 G / W L 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 9,33 × 10 -5 × W L - 70°C-tanδ1 0, 042 0,070 0,071 0,071 0,071 -0, 012 0,073 -0,009 -0,012 plating layer Binary Binary Binary Binary Binary Binary Binary Binary Binary Configuration of steel cord 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 40e 40e 40e 40e 40e 40e 40e 40e 40e S (mm 2 ) 0,141 0, 141 0, 141 0, 141 0, 141 0, 141 0, 141 0, 141 0,141 S × E 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 5, 6 Y / (S × E) 0 1, 8 1, 4 1, 4 1, 4 0 0 0 0 Example Comparative example 25 26 27 28 29 14 15 16 17 [Durability] 120 136 149 170 182 81 93 96 100 Table 7 Example Comparative example 30 31 32 33 34 18 19 20 21 Cover rubber A5 A6 A7 A7 A7 A1 A8 A2 A1 rubber top layer B8 B8 B8 B9 B10 B8 B8 B8 B9 70 °CE*1 (MPa) 13,7 6,2 5,8 5,8 5,8 18,5 20, 1 12, 8 18,5 70 °C-tanδ1 0,061 0,033 0,032 0,032 0,032 0,115 0,030 0,112 0,115 Total styrene amount S (mass %) 0 0 0 0 0 0 0 0 0 0 °C-tanδ2 0,259 0,259 0,259 0,222 0,297 0,259 0,259 0,259 0,222 30 °C-tanδ2 0,198 0, 198 0, 198 0, 124 0, 120 0,198 0,198 0,198 0,124 0 °C-tanδ2 / 30 °C-tanδ2 1,31 1,31 1,31 1,79 2,48 1,31 1,31 1,31 1,79 Tire weight G (kg) 17,0 17,0 17,0 17,0 17,0 17, 0 17, 0 17, 0 17, 0 Maximum load capacity W L (kg) 1100 1100 1100 1100 1100 1100 1100 1100 1100 G / W L 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 0,0155 9,33 × 10 -5 × W L - 70 °C-tanδ1 0, 042 0, 070 0, 071 0,071 0,071 -0,012 0,073 -0,009 -0,012 plating layer Binary Binary Binary Binary Binary Binary Binary Binary Binary Steel cord configuration 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 1 × 2 40e 40e 40e 40e 40e 40e 40e 40e 40e S (mm 2 ) 0,141 0,141 0, 141 0,141 0,141 0,141 0,141 0,141 0,141 S × E 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 5,6 Y / (S × E) 0 1,8 1,4 1,4 1,4 0 0 0 0 [Durability] 122 140 154 178 191 79 92 96 100 <Ausführungsformen>

[0223] Examples of embodiments of the present invention are shown below. [1] A tire comprising a tread section and a belt layer, wherein the tread section has at least one rubber layer, the belt layer comprising a steel cord and a cover rubber covering the steel cord, wherein a rubber cover layer forming a tread surface of the tread section and the cover rubber each consist of a rubber composition comprising a rubber component and a filler, wherein a complex modulus of elasticity at 70 °C of the cover rubber (70 °CE*1) is 15.0 MPa or less, preferably 14.0 MPa or less, more preferably 12.0 MPa or less and even more preferably 8.0 MPa or less, and wherein in a case where W L in kg represents the maximum load capacity of the tire and 70 °C-tanδ1 represents a tanδ at 70 °C of the outer rubber, W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33×10−5×WL−70 °C−tanδ1>0.023 [2] The tire of [1] above, wherein the filler which is incorporated in the rubber composition which forms the outer rubber comprises silicon dioxide. [3] The tire of [1] or [2] above, wherein the filler incorporated in the rubber composition forming the cover rubber comprises recovered carbon black. [4] The tire from one of [1] to [3] above, wherein a carbon black content based on 100 parts by mass of the rubber component of the rubber composition forming the rubber top layer is 20 parts by mass or less. [5] The tire from one of [1] to [4] above, wherein a tanδ at 30 °C of the rubber cover layer (30 °C-tanδ2) is 0.16 or less. [6] The tire from one of [1] to [5] above, wherein in a case where 30 °C-tanδ2 represents a tanδ at 30 °C of the rubber cover layer and 0 °C-tanδ2 represents a tanδ at 0 °C of the rubber cover layer, 0 °C-tanδ2 / 30 °C-tanδ2 is greater than 2.3. [7] The tire from one of [1] to [6] above, wherein the total amount of styrene in the rubber component forming the rubber cover layer is 15 wt% or less and preferably 13 wt% or less. [8] The tire of one of [1] to [7] above, where W L 400 or more, preferably 500 or more, more preferably 600 or more and even more preferably 700 or more. [9] The tire from one of [1] to [8] above, wherein the steel cord is a simple monofilament cord.

[10] The tire from one of [1] to [9] above, where in a case S is in mm 2 S represents a cross-sectional area of ​​the steel cord and E represents the number of steel cords per 50 mm width in a direction perpendicular to a longitudinal direction of the steel cord, S × E being 1.0 or more and 25 or less, preferably 2.0 or more and 20 or less, more preferably 3.0 or more and 15 or less and even more preferably 4.0 or more and 10 or less.

[11] The tire of

[10] above, wherein in a case where Y represents in mass parts a silicon dioxide content based on 100 mass parts of the rubber component of the rubber composition forming the cover rubber, Y / (S × E) is 0.10 or more, preferably 0.50 or more and further preferably 1.0 or more.

[12] The tire from [1] to

[11] above, wherein the steel cord has a ternary plating layer consisting of copper, zinc and cobalt.

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

[12] above, where in one case G in kg represents a tire weight, G / W L 0.060 or less, preferably 0.025 or less and further preferably 0.020 or less. REFERENCE MARK LIST 11. Tires 12. Tread section 13. Side wall section 14. Bead section 15. Innerliner 16. Carcass 17th belt layer 18. Bead wire 21, 50. Steel cord 22. Cover rubber 51. Filament CL. Midline< / anwendung> < / kobaltverbindung> < / kautschukkomponente> < / reifen> < / messverfahren> < / definitionen>

Claims

[1] Tire comprising a tread section and a belt layer, wherein the tread section has at least one layer of rubber, wherein the belt layer comprises a steel cord and a cover rubber covering the steel cord, wherein a rubber top layer, which forms a tread surface of the tread section, and the top rubber are each composed of a rubber composition comprising a rubber component and a filler, where a complex elastic modulus at 70 °C of the surface rubber (70 °CE*1) is 15.0 MPa or less, and where in a case where W L in kg represents the maximum load capacity of the tire and 70 °C-tanδ1 represents a tanδ at 70 °C of the outer rubber, W L and 70 °C-tanδ1 satisfy the following inequality (1): 9.33×10−5×WL−70 °C−tanδ1>0.023 [2] Tire according to claim 1, wherein the filler incorporated in the rubber composition forming the outer rubber comprises silicon dioxide. [3] Tires according to claim 1 or 2, wherein the filler incorporated in the rubber composition forming the outer rubber comprises recovered carbon black. [4] Tires according to any one of claims 1 to 3, wherein the carbon black content based on 100 parts by mass of the rubber component of the rubber composition forming the rubber outer layer is 20 parts by mass or less. [5] Tires according to any one of claims 1 to 4, wherein the tanδ at 30 °C of the rubber surface layer (30 °C-tanδ2) is 0.16 or less. [6] Tires according to any one of claims 1 to 5, wherein in a case where 30 °C-tanδ2 represents a tanδ at 30 °C of the rubber surface layer and 0 °C-tanδ2 represents a tanδ at 0 °C of the rubber surface layer, 0 °C-tanδ2 / 30 °C-tanδ2 is greater than 2.

3. [7] Tires according to any one of claims 1 to 6, wherein the total amount of styrene in the rubber component forming the rubber outer layer is 15% by mass or less. [8] Tires according to any one of claims 1 to 7, wherein W L 400 or more. [9] Tires according to any one of claims 1 to 8, wherein the steel cord is a simple monofilament cord. [10] Tires according to any one of claims 1 to 9, wherein in a case where S is in mm 2 S × E represents a cross-sectional area of ​​the steel cord and E represents the number of steel cords per 50 mm width in a direction perpendicular to a longitudinal direction of the steel cord, where S × E is 1.0 or more and 25 or less. [11] Tire according to claim 10, wherein in a case where Y in mass parts represents a silicon dioxide content based on 100 mass parts of the rubber component of the rubber composition forming the cover rubber, Y / (S × E) is 0.10 or more. [12] Tire according to any one of claims 1 to 11, wherein the steel cord has a ternary plating layer consisting of copper, zinc and cobalt. [13] Tires according to any one of claims 1 to 12, wherein in a case where G in kg represents a tire weight, G / W L 0.060 or less.

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