tire

Abstract

The aim is to improve overall performance, including rolling resistance, tire durability at high speeds, and handling stability. [Solution] A tire comprising a carcass with carcass cords, a belt with belt cords provided on the radially outer side of the carcass, a band with band cords provided on the radially outer side of the belt, and a tread provided on the radially outer side of the band, wherein the band cords are band cords containing polyethylene terephthalate fibers, and the tread is formed using a rubber composition containing more than 50 parts by mass of styrene-butadiene rubber (SBR) with a styrene content of less than 25% by mass in 100 parts by mass of rubber component, and furthermore, when the thickness of the tread is T (mm), the amount of styrene in the styrene-butadiene rubber is S (mass%), and the diameter of the band cord is D (mm), the tire satisfies the following (Formula 1). T×S×D<80 (Formula 1)

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In a passenger car tire, as in Patent Document 1, generally, a band (also called a cap ply) is provided between the tread and the belt from the viewpoint of preventing deformation of the tire due to centrifugal force during high-speed driving.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to improve the overall performance of rolling resistance, durability of the tire during high-speed driving, and handling stability.

Means for Solving the Problems

[0005] The present invention is a carcass including a carcass cord, a belt including a belt cord and provided on the outer side in the tire radial direction of the carcass, a band including a band cord and provided on the outer side in the tire radial direction of the belt, and a tread provided on the outer side in the tire radial direction of the band, where the band cord is a band cord containing polyethylene terephthalate fiber,​​​Furthermore, the tire is characterized in that, when the thickness of the tread is T (mm), the amount of styrene in the styrene-butadiene rubber is S (mass%), and the diameter of the band cord is D (mm), it satisfies the following equation (Formula 1). T×S×D<80 (Formula 1) [Effects of the Invention]

[0006] According to the present invention, it is possible to improve the overall performance of rolling resistance, tire durability at high speeds, and handling stability. [Brief explanation of the drawing]

[0007] [Figure 1] This figure illustrates the intersection angle between the circumferential direction of the tire and the longitudinal direction of the belt cord in one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view illustrating a tire according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] [1] Features of the tire according to the present invention First, the features of the tire according to the present invention will be described.

[0009] 1. Overview The tire according to the present invention comprises a carcass having carcass cords, a belt having belt cords and provided on the radially outer side of the carcass, a band having band cords and provided on the radially outer side of the belt, and a tread provided on the radially outer side of the band. The band cord is a band cord containing polyethylene terephthalate (PET) fibers. The tread is formed using a rubber composition containing more than 50 parts by mass of styrene-butadiene rubber (SBR) with a styrene content of less than 25% by mass per 100 parts by mass of rubber component. Furthermore, when the thickness of the tread is T (mm), the amount of styrene in the SBR is S (mass%), and the diameter of the band cord is D (mm), the following equation (Formula 1) is satisfied. T×S×D<80 (Formula 1)

[0010] As a result of these features, as will be described later, it is possible to improve the overall performance of tires using bands, including rolling resistance, tire durability at high speeds, and handling stability.

[0011] 2. Mechanism of effect in the tire according to the present invention The mechanism by which the above-mentioned effects are manifested in the tire according to the present invention is thought to be as follows.

[0012] (1) Use of PET band cord In the tire according to the present invention, the band cord is a band cord containing polyethylene terephthalate (PET) fibers (PET band cord).

[0013] PET fiber has higher rigidity compared to nylon 66 (polyamide synthetic fiber), which has traditionally been used primarily in band cords. Therefore, by using PET cord in band cords, equivalent restraining force can be achieved even with a smaller cord diameter (cord gauge). As a result, the thickness (prep gauge) and weight (prep weight) of the band can be reduced, which is expected to lead to lighter tires and reduced rolling resistance.

[0014] (2) Use of low-styrene SBR in tread rubber compositions However, because PET band cords are more temperature-dependent than nylon 66 (polyamide synthetic fiber), there are concerns that if PET band cords are used as band cords adjacent to the tread, the temperature around the cords will rise at high speeds, leading to a decrease in the rigidity of the band cords and reducing the tire's durability and handling stability at high speeds.

[0015] Therefore, in the present invention, a rubber composition (tread rubber composition) is used to form the tread, which contains more than 50 parts by mass of styrene-butadiene rubber (SBR) with a styrene content of less than 25% by mass in 100 parts by mass of rubber component.

[0016] In other words, since SBR generates less heat the lower its styrene content, using low-styrene SBR with a styrene content of less than 25% by mass is preferable for reducing rolling resistance, i.e., achieving LRR (Low Rolling Resistance).

[0017] Furthermore, when low-styrene SBR (styrene content less than 25% by mass) is included in more than 50 parts by mass per 100 parts by mass of rubber component, an appropriate amount of styrene is generated within the rubber component, making it easier to form styrene domains. By forming such styrene domains, the propagation of impacts and cracks from the tire surface can be suppressed at the interface with the molecular chains of other rubber components, thereby mitigating the forces acting on the tire. This is thought to reduce deformation caused by friction between the tire and the road surface during high-speed driving, thereby improving tire durability and handling stability at high speeds.

[0018] In this invention, "containing more than 50 parts by mass of SBR with a styrene content of less than 25% by mass in 100 parts by mass of rubber component" means that the amount of SBR in 100 parts by mass of rubber component is more than 50 parts by mass, and the amount of styrene in the total SBR is less than 25% by mass.

[0019] In other words, if styrene-containing polymer (SBR) is included alone in the rubber component, it indicates that the amount of styrene is less than 25% by mass. If multiple styrene-containing polymers (SBR) are included in the rubber component, it indicates that the total amount of styrene, calculated by the product of the amount of styrene (by mass) in each polymer and the amount of that polymer blended per 100 parts by mass of the rubber component (parts by mass), is less than 25% by mass.

[0020] More specifically, for example, if 100 parts by mass of rubber component contains SBR1 (X1 parts by mass) with a styrene content of S1% by mass and SBR2 (X2 parts by mass) with a styrene content of S2% by mass, this indicates that the amount of styrene calculated from the formula {(S1 × X1) + (S2 × X2)} / (X1 + X2) is less than 25% by mass.

[0021] Furthermore, in the rubber composition after vulcanization, the amount of styrene contained in the rubber component after acetone extraction can also be calculated by determining it using solid-state nuclear magnetic resonance (solid-state NMR) or Fourier transform infrared spectrophotometer (FTIR).

[0022] (3) Relationship between tread thickness, styrene content, and band cord diameter In this invention, when the tread thickness is T (mm), the amount of styrene in SBR is S (mass%), and the diameter of the band cord is D (mm), the following equation (Equation 1) is satisfied. T×S×D<80 (Formula 1)

[0023] A smaller band cord diameter D (mm) can reduce tire weight and thus rolling resistance (LRR), but this can decrease the rigidity of the band cord, potentially reducing tire durability and handling stability at high speeds.

[0024] On the other hand, the lower the styrene content (mass%) in SBR, the lower the heat generation, which can reduce rolling resistance (LRR). By including an appropriate amount of low-styrene SBR, it is possible to improve tire durability and handling stability at high speeds.

[0025] Furthermore, the thinner the tread thickness T (mm), the lighter the tire weight can be, which in turn reduces heat generation and thus lowers rolling resistance.

[0026] Considering the above, by appropriately controlling the relationship between the diameter D (mm) of the PET band cord, the amount of styrene S (mass%) in the SBR, and the tread thickness T (mm), specifically by controlling their product (T × S × D) to be less than 80, it is possible to create a tread design that is advantageous for high-speed driving and generates less heat while maintaining the benefits of weight reduction. Furthermore, it is possible to ensure tire durability and handling stability at high speeds while maintaining the modulus of the PET band cord, thereby improving the overall performance of rolling resistance and tire durability and handling stability at high speeds.

[0027] In the above, the "diameter of the band cord" can be measured in accordance with the method specified in JIS L1017:2002 "Test method for chemical fiber tire cords". If the circumscribed circle of the cross-section perpendicular to the direction of cord extension is a perfect circle, it refers to the diameter. If it is an ellipse or the like, it refers to the equivalent diameter of the circle (the diameter of the circle assuming a perfect circle with the same cross-sectional area).

[0028] Furthermore, "tread thickness" refers to the thickness of the tread on the tire's equatorial plane in the tire's radial cross-section. When the tread is formed from a single rubber composition, it refers to the thickness of that rubber composition. When it is formed from a laminated structure of multiple rubber compositions, as described later, it refers to the thickness of the cap rubber layer, which is the outermost layer on the contact surface side. This can be measured by cutting the tire radially and aligning the bead portion with the normal rim width.

[0029] Furthermore, "standard rim" refers to the rim specified for each tire within the standard system that includes the standard on which the tire is based. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," for ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." Refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. In the case of tires not specified in the standard, it refers to the rim with the smallest diameter and the narrowest rim width among rims that can be mounted on and can maintain internal pressure, i.e., rims that do not cause air leakage from between the rim and tire.

[0030] [2] More preferred embodiment of the tire according to the present invention The tire according to the present invention can achieve even greater effects by adopting the following embodiments.

[0031] 1. Use of single-ply PET band cord In the present invention, it is preferable to use a single-ply PET band cord, which is made by twisting together a single yarn containing PET fibers, as the PET band cord.

[0032] By using a single-strand PET band cord, it is possible to create a more rigid band even with a reduced cord diameter, thereby reducing the weight of the tire and lowering rolling resistance.

[0033] The filaments that make up the yarn may consist solely of PET fibers, or they may be a mixture of PET fibers and other fibers (such as polyamide fibers).

[0034] The specific diameter D of the band cord is preferably greater than 0.2 mm, and more preferably greater than 0.4 mm. The upper limit is preferably less than 0.8 mm, and more preferably less than 0.6 mm.

[0035] Furthermore, the gauge on the band's cord is preferably 0.01 mm or more, and more preferably 0.03 mm or more. The upper limit is preferably 0.05 mm or less, and more preferably 0.04 mm or less. Also, the total gauge of the band is preferably 0.20 mm or more, and more preferably 0.30 mm or more. The upper limit is preferably 0.60 mm or less, and more preferably 0.50 mm or less.

[0036] Furthermore, it is preferable that the PET fiber is a sustainable material that is compatible with environmental protection. Examples of sustainable PET fibers (sustainable PET fibers) include PET fibers recycled from plastic waste such as used PET bottles, old items, and waste materials (recycled PET fibers), and PET fibers manufactured from biomass (bio-PET fibers).

[0037] A band comprising a PET cord can be manufactured by treating the PET cord with an adhesive and then bonding it to a predetermined rubber composition for bands. As adhesives used to bond the PET cord, for example, epoxy compounds such as EX-313 (glycerin polyglycidyl ether, manufactured by Nagase ChemteX Corporation) and RFL (resorcinol-formaldehyde latex) can be used.

[0038] Furthermore, the band may consist of one or two layers. The band may also be formed across the entire width of the tread, or only at the ends of the tread.

[0039] Furthermore, the number of cords per 50 mm of band cord width (ends: cords / 5 cm) is preferably more than 30 cords / 5 cm, more preferably more than 40 cords / 5 cm, and even more preferably more than 45 cords / 5 cm. Increasing the number of ends increases the rigidity of the band and enhances the effect of suppressing belt vibration, which is thought to improve tire durability at high speeds. There is no particular upper limit, but it is preferably less than 70 cords / 5 cm, more preferably less than 60 cords / 5 cm, and even more preferably less than 55 cords / 5 cm.

[0040] The end length of the band cord described above can be measured in accordance with the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0041] 2. Tread (1) Amount of styrene in SBR In the present invention, the amount of styrene in SBR is less than 25% by mass, as described above, but is more preferably 20% by mass or less, and even more preferably 18% by mass or less. On the other hand, as a lower limit, it is preferably 5% by mass or more, and more preferably 10% by mass or more.

[0042] (2) Content of low styrene SBR In the present invention, the amount of low-styrene SBR contained in 100 parts by mass of rubber component is more than 50 parts by mass, as described above, but more preferably more than 60 parts by mass, considering the formation of more appropriate styrene domains. The upper limit is preferably less than 80 parts by mass, and more preferably less than 70 parts by mass.

[0043] (3) Relationship between tread thickness, styrene content, and band cord diameter In the present invention, the product of the diameter D (mm) of the PET band cord, the amount of styrene S (mass%) in the SBR, and the thickness T (mm) of the tread (T × S × D) is controlled to be less than 80, as described above, but more preferably less than 70, and even more preferably less than 65. As a lower limit, for example, it is preferably greater than 35, more preferably greater than 40, and even more preferably greater than 45.

[0044] (4) Silica In the present invention, it is preferable that the tread rubber composition contains more than 75 parts by mass of silica per 100 parts by mass of rubber component. By including a large amount of silica having OH groups on its surface, more than 75 parts by mass per 100 parts by mass of rubber component, hydrogen bonds are formed between the silica surfaces and also interact with the rubber component, so that force can be easily generated and transmitted within the rubber during driving. As a result, it is possible to easily transmit the force generated during turning, and it is believed that excellent handling stability can be ensured. It is more preferable to have 80 parts by mass or more, and even more preferable to have 90 parts by mass or more. As an upper limit, for example, it is preferable to have 200 parts by mass or less, more preferably 150 parts by mass or less, and even more preferable to have 100 parts by mass or less.

[0045] Furthermore, when incorporating silica, if the particle size (average primary particle size) is too small, the processability will be poor, so it is preferable to use silica with a particle size greater than 8 nm. It is more preferable if it is 9 nm or larger, and even more preferable if it is 10 nm or larger. On the other hand, from the viewpoint of ensuring the reinforcing properties of the rubber, it is preferable if it is 25 nm or smaller, more preferably 20 nm or smaller, and even more preferable if it is 17 nm or smaller.

[0046] The average primary particle diameter of silica refers to the average value of measurements taken by observing the smallest particle unit of silica constituting the aggregated structure as a circle, and measuring the absolute maximum length of that smallest particle as the diameter of the circle. This can be determined by observing with a transmission or scanning electron microscope, measuring 400 or more primary silica particles observed within the field of view, and averaging the results.

[0047] Specifically, silica extracted from the rubber composition cut from a tire can be directly observed using an electron microscope or similar device. The average primary particle diameter can then be calculated by determining the average of the equal cross-sectional area diameters from the area of ​​each silica particle obtained and then calculating the average value.

[0048] (5) Acetone extract (AE amount) Furthermore, in the present invention, the amount of AE in the tread rubber composition is preferably more than 15% by mass, and more preferably more than 20% by mass. As an upper limit, for example, it is preferably less than 30% by mass, and more preferably less than 25% by mass.

[0049] The amount of air-exposure (AE) can be considered an indicator of the amount of material that imparts plasticity to the rubber components, such as softeners (plasticizers), in a rubber composition, and can also be considered an indicator of the softness of the rubber composition. Therefore, if the amount of AE in the tread rubber composition is increased to a certain extent, such as more than 15% by mass, the tread blocks will be able to deform more flexibly, ensuring a sufficient contact area with the road surface even at high speeds, suppressing heat generation due to the concentration of contact pressure, and thus further improving the durability of the tire at high speeds.

[0050] The amount of AE can be measured in accordance with JIS K 6229:2015. Specifically, the amount of AE (mass%) can be obtained by immersing a vulcanized rubber test piece cut from the measurement site in acetone for a predetermined time and determining the mass loss rate (%) of the test piece.

[0051] More specifically, the soluble components can be extracted by immersing each vulcanized rubber test piece in acetone for 72 hours at room temperature and atmospheric pressure, measuring the mass of each test piece before and after extraction, and then determining the result using the following formula. AE amount (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction)} / (mass of rubber test piece before extraction)} × 100

[0052] The amount of AE can be appropriately changed by altering the blending ratio of plasticizers in the rubber composition.

[0053] (6) Tread thickness In the present invention, the tread thickness is preferably greater than 6 mm, which is thought to reduce the compression the band receives and improve the tire's durability during high-speed driving. It is more preferably 8 mm or more, and even more preferably 10 mm or more. As an upper limit, for example, it is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 12 mm or less.

[0054] (7) Multi-layering of the tread In the present invention, the tread may consist of only one layer, which is the contact surface layer (cap rubber layer), or it may consist of two layers, with a base rubber layer provided inside the cap rubber layer, or it may consist of three layers, or four or more layers. In this case, the rubber composition for the tread described above is the rubber composition that forms the cap rubber layer, which is the outermost layer on the contact surface side, and it is preferable that it satisfies each of the above parameters.

[0055] In this case, the thickness of the cap rubber layer over the entire tread is preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and even more preferably 70% or more.

[0056] 3. Belt In this invention, it is preferable that the belt cord constituting the belt is composed of four or fewer filaments. By reducing the number of filaments in this way, even if the filaments are made of metal, the weight can be reduced, thereby reducing the weight of the tire, and thus reducing rolling resistance and improving fuel efficiency.

[0057] The material of the filaments constituting the belt cord is not particularly limited, but it is preferably made of metal, more preferably iron, and especially preferably steel. The structure of the belt cord is preferably one of the following: an untwisted 1x1 structure, a single-twist 1x2 structure, a 1x3 structure, a 1x4 structure, or a layered 2+2 structure. The cross-sectional shape of the filaments is preferably circular, but they may also be elliptical, and they may also be corrugated or plated.

[0058] Furthermore, in the present invention, it is preferable that the intersection angle, which is the smaller of the angles formed by the tire circumferential direction and the longitudinal direction of the belt cord when the tread is viewed in plan in the tire radial direction, is less than 25 degrees. It is more preferable that it is less than 24 degrees. As a lower limit, it is preferable that it is greater than 0 degrees, and more preferable that it is greater than 20 degrees.

[0059] Specifically, as shown in Figure 1, the smaller of the angles θ between the longitudinal direction of the belt cords 8a, 8a, ... constituting the belt 8 and the center line CL in the circumferential direction of the tire is used as the intersection angle and is controlled to be less than 25 degrees.

[0060] By reducing the intersection angle in this way, the tread rigidity can be increased, leading to an increase in restraint force. This is thought to improve responsiveness during driving and enhance handling stability.

[0061] Furthermore, by reducing the intersection angle, the contact shape can be flattened, thus negating the disadvantage that the contact shape tends to become rounded when using band cords made of PET cord. By combining the increased restraint force from using PET cord with the increased restraint force from reducing the intersection angle of the lightweight belt cord, it is believed that the durability of the tire at high speeds can be improved.

[0062] In this invention, the intersection angle shall be expressed as an absolute value without a ± sign, in accordance with the definition above, even if the direction of inclination of the belt cord is opposite to the circumferential direction of the tire. Furthermore, if there are, for example, two or more belt layers, each with a different intersection angle, it is sufficient that the intersection angle of at least one belt layer is less than 25 degrees.

[0063] Furthermore, the diameter of the belt cord is preferably 0.42 mm or more, more preferably 0.45 mm or more, and even more preferably 0.47 mm or more. As an upper limit, for example, it is preferably 0.56 mm or less, more preferably 0.53 mm or less, and even more preferably 0.50 mm. This allows for a thinner belt section, which is thought to improve the overall performance of tire durability and handling stability during high-speed driving.

[0064] Furthermore, in the above, the "belt cord diameter" can be measured in accordance with the test method specified in JIS G3510:1992 "Test method for steel tire cords".

[0065] Furthermore, the number of cords per 50 mm of belt cord width (ends: cords / 5 cm) is preferably 20 cords / 5 cm or more, more preferably 25 cords / 5 cm or more, and even more preferably 30 cords / 5 cm or more. As an upper limit, for example, it is preferably 60 cords / 5 cm or less, more preferably 55 cords / 5 cm or less, and even more preferably 50 cords / 5 cm or less.

[0066] The end length of the belt cord described above can be measured in accordance with the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0067] 4. Carcass In the present invention, it is preferable to use a carcass formed using carcass cords with a fineness of more than 2300 dtex.

[0068] By forming the carcass using carcass cords with a fineness exceeding 2300 dtex and a certain thickness or greater, the lateral spring constant can be increased, thereby changing (reducing) the degree of deflection that occurs in the sidewall during driving. This is thought to ensure tire strength, improve handling stability, and enhance tire durability at high speeds. A fineness exceeding 3300 dtex is even more preferable. As an upper limit, for example, a fineness of less than 4000 dtex is preferable.

[0069] The total fineness of the carcass cords mentioned above can be measured in accordance with the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0070] Carcass cords can be made of fibers, and conventionally known fibers can be used to make up the carcass cord, such as polyester fibers like PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers, polyamide fibers like nylon 6 fibers and nylon 66 fibers, and aramid fibers. Single-ply cords made by twisting one yarn or double-ply cords made by twisting two yarns are preferred. The fibers that make up the carcass cord may be recycled from used or waste materials (recycled materials) or synthesized from biomass (biomass materials).

[0071] The carcass can be one layer or two layers, but one layer is preferable. By using a single-layer carcass, it is thought that the tire can be made lighter and lighter (LRR) can be achieved compared to using a two-layer carcass.

[0072] Furthermore, by using such a carcass structure, the axial bending rigidity can be sufficiently reduced, allowing the side sections to flex sufficiently when a camber angle is applied during cornering, and thus increasing the contact area of ​​the tread with the ground. This is thought to improve handling stability.

[0073] The specific diameter of the carcass cord is preferably 0.70 mm or less, and more preferably 0.65 mm or less. The lower limit is preferably 0.55 mm or more, and more preferably 0.60 mm or more.

[0074] In the above, the "diameter of the carcass cord" can be measured in accordance with the method specified in JIS L1017:2002 "Test method for chemical fiber tire cords".

[0075] Furthermore, the number of cords per 50 mm of carcass width (ends: cords / 5 cm) is preferably 40 cords / 5 cm or more, and more preferably 45 cords / 5 cm or more. As an upper limit, for example, it is preferably 60 cords / 5 cm or less, and more preferably 55 cords / 5 cm or less.

[0076] The end length of the carcass cord described above can be measured in accordance with the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0077] [3] Embodiment The present invention will be described in detail below based on embodiments.

[0078] 1. Tire according to this embodiment Figure 2 is a schematic cross-sectional view illustrating the tire according to this embodiment. In Figure 2, the vertical direction is the radial direction of the tire, the horizontal direction is the rotation axis direction of the tire, and the direction perpendicular to the plane of the paper is the circumferential direction of the tire. Note that, except for the tread pattern, the shape of this tire is symmetrical with respect to the equatorial plane, so Figure 2 shows 1 / 4 of the entire tire.

[0079] As shown in Figure 2, the tire 1 comprises a tread 2, a pair of sidewalls 3, a pair of chafers 4, a pair of beads 5, an inner liner 6, a carcass 7, a belt 8, a pair of fillers 9, and a band 10, with the carcass 7, belt 8, band 10, and tread 2 arranged from the inside to the outside in the radial direction of the tire.

[0080] With this configuration, as described above, PET band cords are used as band cords, and the tread is formed using an appropriately formulated rubber composition for the tread. Furthermore, by appropriately controlling the product of the tread thickness, the amount of styrene in the SBR, and the diameter of the band cords, it is believed that the overall performance of rolling resistance, tire durability at high speeds, and handling stability can be improved.

[0081] 2. Rubber composition for treads In this embodiment, the tread rubber composition can be obtained by kneading various compounding materials such as rubber components, reinforcing materials, antioxidants, oils, resin materials, and antioxidants.

[0082] (1) Compounding materials (a) Rubber component The rubber component in the tread rubber composition is not particularly limited, and for example, diene rubbers such as natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR) can be used. These may be used individually or in combination of two or more, and in the present invention, a combination of NR, SBR, and BR is preferred.

[0083] (i) SBR The weight-average molecular weight of SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content in SBR is as described above. The vinyl content (amount of 1,2-bonded butadiene units) of SBR is preferably more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and even more preferably less than 30% by mass. The structural identification of SBR (measurement of styrene content and vinyl content) can be performed, for example, using an instrument from the JNM-ECA series manufactured by JEOL Ltd.

[0084] The SBR is not particularly limited, and for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc., can be used. The SBR may be either unmodified SBR or modified SBR. Furthermore, hydrogenated SBR, in which the butadiene portion of the SBR is hydrogenated, may be used. Hydrogenated SBR may be obtained by subsequently hydrogenating the BR portion of the SBR, or a similar structure may be obtained by copolymerizing styrene, ethylene, and butadiene.

[0085] The modified SBR is preferably an SBR having a functional group that interacts with a filler such as silica. Examples include a terminally modified SBR (terminally modified SBR having the functional group at the terminal) in which at least one end of the SBR is modified with a compound having the functional group (modifying agent), a main chain modified SBR having the functional group in the main chain, a main chain terminally modified SBR having the functional group in both the main chain and the terminal (for example, a main chain terminally modified SBR having the functional group in the main chain and at least one end modified with the modifying agent), and a terminally modified SBR that is modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and in which hydroxyl groups or epoxy groups are introduced.

[0086] Examples of the above-mentioned functional groups include amino groups, amide groups, silyl groups, alkoxysilyl groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, thiocarbonyl groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, and the like. These functional groups may also have substituents.

[0087] Furthermore, as modified SBR, for example, SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0088] [ka]

[0089] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH) or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0090] As the modified SBR modified with the compound (modifying agent) represented by the above formula, SBR in which the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) is modified with the compound represented by the above formula (modified SBR described in JP-A-2010-111753, etc.) can be used.

[0091] R 1 , R 2 and R 3 is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). R 4 and R 5 is preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Also, when R 4 and R 5 combine to form a ring structure together with a nitrogen atom, it is preferably a 4- to 8-membered ring. Note that the alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0092] Specific examples of the above-mentioned denaturing agents include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These may be used individually or in combination of two or more.

[0093] Furthermore, modified SBR can also be modified using the following compounds (modifying agents): For example, polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidyl bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxylated liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, Diglycidylamino compounds such as diglycidyl orthotoluidine, tetraglycidylmetoxylendiamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamate chloride, 4-morpholine carbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamate chloride, and N,N-diethylcarbamate chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide Sulfide group-containing silane compounds such as [sisilyl)propyl]sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyl Alkoxysilanes such as tiltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group, such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; 4-N,N- Benzaldehyde compounds having an amino group and / or a substituted amino group, such as dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam; as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones. Examples include N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophene, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, and 1,7-bis(methylethylamino)-4-heptanone. Modification using the above compounds (modifiers) can be carried out by known methods.

[0094] For example, SBR manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., ENEOS Material Co., Ltd., Asahi Kasei Corporation, and Nippon Zeon Co., Ltd. can be used. SBR may be used alone or in combination of two or more types.

[0095] As mentioned above, the amount of SBR contained in 100 parts by mass of rubber component is more preferably more than 60 parts by mass, preferably less than 80 parts by mass, and more preferably less than 70 parts by mass.

[0096] (b) Isoprene rubber Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR, but NR is preferred due to its superior strength.

[0097] For NR, common types used in the tire industry can be used, such as SVR-L, SIR20, RSS#3, and TSR20. For IR, there are no particular limitations, and common types used in the tire industry can be used, such as IR2200 manufactured by Nippon Zeon Co., Ltd. Modified NRs include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used individually or in combination of two or more types.

[0098] The isoprene-based rubber content in 100 parts by mass of rubber components is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. As an upper limit, for example, it is preferably 25 parts by mass or less, and more preferably 20 parts by mass or less.

[0099] (H)BR The weight-average molecular weight of BR is, for example, greater than 100,000 and less than 2,000,000. The vinyl content of BR is, for example, greater than 1% by mass and less than 30% by mass. The cis content of BR is, for example, greater than 1% by mass and 98% by mass or less. The trans content of BR is, for example, greater than 1% by mass and less than 60% by mass. The cis content can be measured by infrared absorption spectroscopy.

[0100] The BR is not particularly limited, and can be high-cis content BR (cis content of 90% or more), low-cis content BR, or BR containing syndiotactic polybutadiene crystals. The BR can be either unmodified or modified, and as for modified BR, for example, BR modified with a compound (modifying agent) represented by the following formula can be used.

[0101] [ka]

[0102] Note that in the formula, R 1 , R 2and R 3 R represents, either identical or distinct, an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. 4 and R 5 R represents a hydrogen atom or an alkyl group, either identical or different. 4 and R 5 These atoms may bond to form a ring structure with the nitrogen atom. n represents an integer.

[0103] Modified BR, which has been modified by the compound (modifying agent) represented by the above formula, is an example of BR in which the polymerization end (active end) has been modified by the compound represented by the above formula.

[0104] R 1 , R 2 and R 3 A suitable alkoxy group is used (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). 4 and R 5 A suitable alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is used. n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. Also, R 4 and R 5 When the alkoxy group is bonded to form a ring structure with the nitrogen atom, it is preferably a 4- to 8-membered ring. Note that the alkoxy group also includes cycloalkoxy groups (such as cyclohexyloxy group) and aryloxy groups (such as phenoxy group and benzyloxy group).

[0105] Specific examples of the above-mentioned denaturing agents include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These may be used individually or in combination of two or more.

[0106] Furthermore, modified BR can also be modified using the following compounds (modifying agents): For example, polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidyl bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxy-modified liquid polybutadiene; epoxy-group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, Diglycidylamino compounds such as diglycidyl orthotoluidine, tetraglycidylmetoxylendiamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamate chloride, 4-morpholine carbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamate chloride, and N,N-diethylcarbamate chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (Trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide Sulfide group-containing silane compounds such as [sisilyl)propyl]sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyl Alkoxysilanes such as tiltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group, such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; 4-N,N- Benzaldehyde compounds having an amino group and / or a substituted amino group, such as dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam; as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones. Examples include N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophene, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, and 1,7-bis(methylethylamino)-4-heptanone. Modification using the above compounds (modifying agents) can be carried out by known methods. These modified BRs may be used individually or in combination of two or more.

[0107] For example, BR products from companies such as Ube Industries, Ltd., ENEOS Material Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used.

[0108] The BR content in 100 parts by mass of rubber component is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more. On the other hand, it is preferably 30 parts by mass or less, and more preferably 25 parts by mass or less.

[0109] (ii) Other rubber components The tread rubber composition may also include, if necessary, other rubber components such as nitrile rubber (NBR) or other rubbers (polymers) commonly used in tire manufacturing.

[0110] Furthermore, the raw materials (monomers) for synthetic rubbers such as SBR and BR mentioned above may be derived from underground resources such as petroleum and natural gas, or they may be recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0111] The monomers obtained by recycling (recycled monomers) are not particularly limited and include recycled isoprene, recycled butadiene, and recycled aromatic vinyl. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl include styrene. In particular, recycled isoprene, butadiene, and / or recycled styrene are preferred as raw materials.

[0112] The method for producing recycled monomer is not particularly limited, and for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Furthermore, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and pressure, decomposed by microwaves, or extracted after mechanical grinding.

[0113] Furthermore, the raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR may be derived from biomass. Here, biomass refers to substances derived from natural resources such as plants. Biomass is not particularly limited, but examples include agricultural, forestry, and fishery products, sugars, wood, plant residues after obtaining useful components, plant-derived ethanol, and biomass naphtha. Biomass-derived monomers (biomass monomers) are not particularly limited, but examples include biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl are not particularly limited, but examples include styrene. In addition, the method for producing biomass monomers is not particularly limited, and examples include biological and / or chemical and / or physical conversion of plants and animals. Typical biological conversions include fermentation by microorganisms, while chemical and / or physical conversions include those by catalysts, high heat, high pressure, electromagnetic waves, critical liquids, and combinations thereof.

[0114] The polymer synthesized from biomass monomer components (biomass polymer) is not particularly limited, and examples include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0115] Whether the raw materials for a polymer are biomass-derived can be determined by measuring pMC (percent Modern Carbon) in accordance with ASTMD6866-10.

[0116] pMC stands for Modern Standard Reference Carbon. 14 Sample relative to C concentration 14This is the ratio of C concentrations, and this value is used as an indicator of the biomass ratio of the compound (rubber). The significance of this value is described below.

[0117] 1 mole of carbon atoms (6.02 × 10⁻¹⁰) 23 (Each) contains approximately 6.02 × 10¹⁶ atoms, which is about one trillionth of the amount of carbon atoms in a normal atom. 11 individual 14 C exists. 14 Carbon dioxide is called a radioactive isotope, and its half-life is 5730 years, decreasing regularly. It takes 226,000 years for all of them to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been fixed for more than 226,000 years after atmospheric carbon dioxide was taken in by plants, etc., it was initially contained within these materials. 14 All elements of C have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas are no longer viable. 14 It contains absolutely no element C. Therefore, chemical substances produced using these fossil fuels as raw materials also contain C. 14 It contains absolutely no element C.

[0118] on the other hand, 14 C is continuously produced in the Earth's atmospheric environment through nuclear reactions caused by cosmic rays, and its decrease due to radioactive decay balances this process. 14 The amount of C is constant. Therefore, the amount of biomass resource-derived substances currently circulating in the environment 14 As mentioned above, the carbon concentration is approximately 1 × 10¹⁶ of the total carbon atoms. -12 The values ​​are approximately in the range of mol%. Therefore, by using the difference between these values, it is possible to calculate the ratio (biomass ratio) of compounds derived from natural resources (compounds derived from biomass resources) in a given compound (rubber).

[0119] this 14 C is typically measured as follows: Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 Perform measurement C). In the measurement, 14 As a modern standard reference for the concentration of C, the amount of cyclic carbon in nature as of 1950 14 The C concentration will be used. The specific standard material will be the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific radioactivity of carbon in this oxalic acid (per gram of carbon) will be used. 14 The radioactivity intensity of C is separated by carbon isotope, 13 The standard value is obtained by correcting C to a constant value and applying decay correction from 1950 AD to the measurement date. 14 This value is used as the C concentration value (100%). The ratio of this value to the value of the sample actually measured is the pMC value.

[0120] Therefore, if rubber is made from 100% biomass (natural) materials, although there are regional differences, under normal conditions it will often not reach 100, and will show a value of approximately 110 pMC. On the other hand, regarding chemical substances derived from fossil fuels such as petroleum, 14 When the C concentration is measured, it will show a value of approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0121] From the above, it is preferable from an environmental protection (sustainability) standpoint to use materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in rubber compositions.

[0122] (b) Compounding materials other than rubber components (i) Filler As described above, the tread rubber composition contains silica as a reinforcing agent, but may also contain other fillers as needed, such as carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. When silica is used, it is preferable to use it in combination with a silane coupling agent.

[0123] Regarding the amount of fillers to be added, firstly, as mentioned above, silica should be added in an amount of more than 75 parts by mass per 100 parts by mass of rubber component. However, the total amount of other fillers added is preferably 80 parts by mass or more, and more preferably 85 parts by mass or more, per 100 parts by mass of rubber component. On the other hand, from the viewpoint of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, and more preferably 100 parts by mass or less.

[0124] (i) Silica In the tread rubber composition, the silica content per 100 parts by mass of rubber component is as described above.

[0125] The BET specific surface area of ​​silica is considered to be 100 m² from the perspective of obtaining good durability performance. 2 It is preferable that the amount is greater than / g, and 130m 2 It is more preferable if it is greater than / g. On the other hand, 250m 2 It is preferable that the amount be less than / g, and 200m 2 It is more preferable if the value is less than / g. The BET specific surface area mentioned above is the N2SA value measured by the BET method in accordance with ASTM D3037-93.

[0126] The silica used is not particularly limited; for example, silica prepared by the dry method (anhydrous silica), silica prepared by the wet method (hydrated silica), and other types commonly used in the tire industry can be used. Commercially available products from companies such as Evonik Industries, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Ltd., and Tokuyama Corporation can be used.

[0127] The raw materials for silica are not particularly limited. For example, they may be mineral-derived raw materials such as quartz, or biologically derived raw materials such as rice husks (e.g., silica made from biomass materials such as rice husks), or silica recycled from silica-containing products may be used. Among these, hydrated silica prepared by a wet process is preferred because it contains a large amount of silanol groups. However, from an environmental protection standpoint, sustainable silica (silica made from biomass materials or silica recycled from silica-containing products) is preferred.

[0128] Silica derived from biomass materials (biomass silica) can be obtained, for example, by extracting silicates from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then using these silicates to react with sulfuric acid in the same way as conventional wet silica, the precipitate of silicon dioxide is filtered, washed with water, dried, and pulverized.

[0129] Recycled silica (silica recycled from silica-containing products) can be obtained from silica-containing products such as semiconductors and other electronic components, tires, desiccants, and diatomaceous earth and other filter materials. The recovery method is not particularly limited and can include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from semiconductors and other electronic components or tires is preferred.

[0130] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol.6, pp.216-222, etc.).

[0131] Amorphous silica extracted from rice husks can be commercially available from companies such as Wilmar.

[0132] These silicas may be used individually or in combination of two or more. Furthermore, using sustainable silica such as biomass silica or recycled silica is preferable from an environmental protection (sustainability) standpoint.

[0133] (ii) Silane coupling agent When using silica, it is preferable to use a silane coupling agent in combination to improve the dispersibility of silica and to enhance mechanical properties and moldability through reaction with silica.

[0134] The silane coupling agent is not particularly limited and includes, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)tri Sulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilyl Examples of silane coupling agents include sulfide-based agents such as ethyl-N,N-dimethylthiocarbamoyl tetrasulfide and 3-triethoxysilylpropyl methacrylate monosulfide, mercapto-based agents such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z from Momentive, vinyl-based agents such as vinyltriethoxysilane and vinyltrimethoxysilane, amino-based agents such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy-based agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, nitro-based agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, and chloro-based agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, silane coupling agents having a thiocarbonyl group, such as NXT mentioned above, are preferred. These may be used alone or in combination of two or more.

[0135] Examples of silane coupling agents that can be used include products from Evonik Industries, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd.

[0136] The silane coupling agent content is preferably more than 3 parts by mass, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of silica. The upper limit is preferably less than 15 parts by mass, more preferably 12 parts by mass or less, and even more preferably 9 parts by mass or less.

[0137] (iii) Carbon Black It is preferable to include carbon black in the tread rubber composition for the purpose of improving the tire's crack growth resistance, durability, and resistance to UV degradation.

[0138] The nitrogen adsorption specific surface area (N2SA) of carbon black is, from the perspective of its reinforcing properties for rubber, for example, 30m². 2 It is preferable that it be 50m or more / g 2 It is more preferable that it is 60m or more / g 2 It is even more preferable if it is 1 / g or more. On the other hand, from the viewpoint of exothermic properties, 250m 2 It is preferable that it be less than or equal to / g, and 150m 2 It is more preferable that it be less than or equal to / g, and 120m 2 It is even more preferable if the amount is less than or equal to / g. The specific surface area of ​​nitrogen adsorption of carbon black is measured according to ASTM D4820-93.

[0139] From the viewpoint of rubber rigidity, the amount of dibutyl phthalate (DBP) absorbed by carbon black is preferably 50 ml / 100g or more, and more preferably 100 ml / 100g or more. On the other hand, from the viewpoint of the rubber's ability to follow deformation, it is preferably 250 ml / 100g or less, and more preferably 150 ml / 100g or less. The DBP absorbed by carbon black is measured according to ASTM D2414-93.

[0140] Carbon black is not particularly limited and can include furnace blacks (furnace carbon blacks) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal blacks (thermal carbon blacks) such as FT and MT; and channel blacks (channel carbon blacks) such as EPC, MPC, and CC. Part numbers can include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These can be used individually or in combination of two or more types.

[0141] The raw materials for carbon black may be biomass materials other than mineral oil, such as lignin and vegetable oil, or pyrolysis oil obtained by thermally decomposing rubber products containing carbon black, such as waste tires (recycled carbon black). Using these sustainable carbon blacks is preferable from an environmental protection standpoint.

[0142] Furthermore, the method for producing carbon black may be by combustion such as the furnace process, by hydrothermal carbonization (HTC), or by thermal decomposition of methane such as the thermal black process.

[0143] Commercially available products from companies such as Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Corporation can be used. These can be used individually or in combination of two or more types.

[0144] The carbon black content per 100 parts by mass of rubber component is preferably 3 parts by mass or more, and more preferably 5 parts by mass or more. As an upper limit, for example, it is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less.

[0145] (iv) Other fillers In addition to the silica and carbon black mentioned above, the tread rubber composition may further contain fillers commonly used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, and magnesium sulfate. The amount of these fillers is, for example, more than 0.1 parts by mass and less than 150 parts by mass per 100 parts by mass of the rubber component.

[0146] (b) Softening agent components In rubber compositions, it is preferable to use a softening agent component as needed, taking into consideration the proper dispersion of powder materials during kneading. Here, the softening agent component refers to a material (plasticizer component) that imparts plasticity to the rubber component, and is a concept that includes both softening agent components that are liquid at 25°C and softening agent components that are solid at 25°C.

[0147] Examples of softening agent components include resin components, oils, liquid polymers (liquid rubber), and ester-based plasticizers. These softening agent components may be derived from mineral resources such as petroleum and natural gas, from biomass, or from naphtha recycled from rubber or non-rubber products. In addition, low molecular weight hydrocarbon components obtained by thermal decomposition and extraction of used tires or products containing various components may be used as softening agent components. Among these, softening agent components derived from biomass or recycled materials are preferred as sustainable softening agent components.

[0148] These softening agent components may be used individually or in combination of two or more. The content of the softening agent component per 100 parts by mass of rubber component is preferably 15 parts by mass or more, and more preferably 30 parts by mass or more. The upper limit is preferably 70 parts by mass or less, and more preferably 60 parts by mass or less. The content of the softening agent component also includes the amount of oil contained in the rubber (oil-applied rubber), etc.

[0149] (i) oil Examples of oils include mineral oil, vegetable oil, and animal oil. From a life cycle assessment perspective, waste oil used in rubber mixers and engines, or refined waste cooking oil used in restaurants, may also be used.

[0150] (i-1) Mineral oil Mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oils (mineral oil), naphthenic oils, and aromatic oils.

[0151] Specific examples of mineral oils include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract).

[0152] Furthermore, for environmental reasons, oils with a low content of polycyclic aromatic compounds (PCA) can be used. Examples of such low-PCA oils include MES, TDAE, and heavy naphthenic oils.

[0153] Examples of commercially available mineral oils include paraffinic, aromatic, and naphthenic oils. Products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., and Fuji Kosan Co., Ltd. can be used. These can be used individually or in combination of two or more types.

[0154] (i-2) Vegetable oil Examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and wood wax.

[0155] Furthermore, vegetable oils can also include refined oils (such as salad oil) obtained by refining the above-mentioned oils, transesterified oils obtained by transesterification, hydrogenated oils obtained by hydrogenation, thermally polymerized oils obtained by thermal polymerization, oxidized polymerized oils obtained by oxidation, and waste cooking oils recovered from use as cooking oil. Vegetable oils may be liquid or solid at room temperature (25°C). These may be used individually or in combination of two or more types.

[0156] The vegetable oil preferably contains acylglycerol, and more preferably contains triacylglycerol. Acylglycerol refers to a compound in which a hydroxyl group of glycerin is esterified with a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer of three or more. Acylglycerols of two or more can be obtained by thermal polymerization, oxidative polymerization, etc. Also, the acylglycerol may be a liquid or a solid at room temperature (25°C).

[0157] There are no particular limitations on the method for determining whether a rubber composition contains acylglycerol, 1 This can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, it is measured at room temperature. 1When 1H-NMR is measured and the signal for tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, 4.28 ppm, and 4.15 ppm are observed. These signals are presumed to originate from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group, thus confirming the presence of acylglycerol. Here, "around" refers to a range of ±0.10 ppm.

[0158] The fatty acids are not particularly limited and may be either unsaturated or saturated fatty acids. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0159] In particular, it is desirable that the fatty acid contains fatty acids with few double bonds, i.e., saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As a vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids may be used, or a vegetable oil that has been modified by transesterification or other means may be used. Furthermore, in order to produce a vegetable oil containing such fatty acids, plants may be improved by breeding, genetic modification, genome editing, etc.

[0160] As for vegetable oils, commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Ltd. can be used.

[0161] (ii) Liquid rubber Liquid rubber is a polymer that is in a liquid state at room temperature (25°C) and is a rubber component that can be extracted from vulcanized tires by acetone extraction. Examples of liquid rubber include farnesene polymers, liquid diene polymers, and their hydrogenated derivatives.

[0162] Farnesene polymers are polymers obtained by polymerizing farnesene and have constituent units based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene).

[0163] The farnesene polymer may be a farnesene homopolymer (farnesene homopolymer) or a farnesene-vinyl monomer copolymer (farnesene-vinyl monomer copolymer).

[0164] Examples of liquid diene polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), and liquid styrene-isoprene copolymer (liquid SIR).

[0165] The liquid diene polymer has a weight-average molecular weight (Mw) on a polystyrene basis, measured by gel permeation chromatography (GPC), for example, 1.0 × 10⁻⁶. 3 Super, 2.0×10 5 It is less than [value]. Here, the Mw of the liquid diene polymer is the polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0166] As for liquid rubber, products from companies such as Kuraray Co., Ltd. and Clay Valley Corporation can be used.

[0167] (iii) Resin components The resin component also functions as a tackifying agent and may be solid or liquid at room temperature. Specific examples of resin components include rosin resins, styrene resins, coumarone resins, terpene resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins, and two or more may be used in combination. These resin components may also be modified to include silica or other reactive groups as needed.

[0168] Rosin resins are resins whose main component is rosin acid, obtained by processing pine resin. These rosin resins (rosins) can be classified according to whether or not they are modified, and can be classified into unmodified rosin and rosin derivatives. Examples of unmodified rosin include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionate rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin derivatives are modified forms of unmodified rosin and include rosin esters, unsaturated carboxylic acid-modified rosins, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0169] Styrene resins are polymers that use styrene monomers as constituent monomers, and include polymers polymerized with styrene monomers as the main component (50% by mass or more). Specifically, examples include homopolymers obtained by polymerizing styrene monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) individually, copolymers obtained by copolymerizing two or more styrene monomers, and copolymers of styrene monomers and other monomers that can copolymerize with them.

[0170] Examples of the aforementioned other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylics and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene and butadiene isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or their acid anhydrides; and so on.

[0171] Among coumarone-based resins, coumarone-indene resin is preferred. Coumarone-indene resin is a resin that contains coumarone and indene as monomer components that constitute the resin's backbone (main chain). Other monomer components that can be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0172] The hydroxyl value (OH value) of coumarone indene resin is, for example, greater than 15 mg KOH / g and less than 150 mg KOH / g. The OH value is expressed in milligrams as the amount of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl groups when acetylating 1 g of resin, and is measured by potentiometric titration (JIS K 0070:1992).

[0173] The softening point of coumaron indene resin is, for example, above 30°C and below 160°C. The softening point is determined by measuring the softening point as specified in JIS K 6220-1:2001 using a ring-type softening point measuring device, and it is the temperature at which the sphere descends.

[0174] Examples of terpene resins include polyterpenes, terpene phenols, and aromatically modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are (C5H8) n A hydrocarbon represented by the following composition and its oxygen-containing derivative, a monoterpene (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpene (C 20 H 32 These are compounds with a terpene as their basic skeleton, classified as such, and examples include α-pinene, β-pinene, dipentene, limonene, myrcene, allocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0175] Polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which are made from the terpene compounds mentioned above, as well as hydrogenated terpene resins obtained by hydrogenating these terpene resins. Terpene phenols include resins obtained by copolymerizing the above terpene compounds with phenolic compounds, and resins obtained by hydrogenating these resins. Specifically, resins obtained by condensing the above terpene compounds, phenolic compounds, and formalin are included. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Aromatically modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating these resins. The aromatic compounds are not particularly limited as long as they are compounds having an aromatic ring, but examples include phenol compounds such as phenol, alkylphenol, alkoxyphenol, and phenol containing an unsaturated hydrocarbon group; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and naphthol containing an unsaturated hydrocarbon group; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and styrene containing an unsaturated hydrocarbon group; coumarone, indene, and others.

[0176] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene. Dicyclopentadiene resin (DCPD resin) is preferably used as a C5-based petroleum resin.

[0177] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be hydrogenated or modified. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples include coumarone indene resin, coumarone resin, indene resin, and aromatic vinyl resins, which are suitably used. As aromatic vinyl resins, α-methylstyrene (AMS resin), a homopolymer of styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, due to their economical nature, ease of processing, and excellent heat generation properties. Aromatic vinyl resins that are commercially available from companies such as Kraton and Eastman Chemical can be used.

[0178] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be hydrogenated or modified. Examples of the C5 and C9 fractions include the petroleum fractions mentioned above. As for the C5C9 resin, commercially available products from companies such as Tosoh Corporation and LUHUA can be used.

[0179] While there are no particular limitations on the acrylic resin used, for example, a solvent-free acrylic resin can be used.

[0180] Solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized by high-temperature continuous polymerization (high-temperature continuous mass polymerization) (methods described in U.S. Patent No. 4,414,370, Japanese Patent Publication No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Publication No. 1-313522, U.S. Patent No. 5,010,166, Toa Gosei Research Annual Report TREND2000 No. 3 pp. 42-45, etc.) with minimal use of polymerization initiators, chain transfer agents, organic solvents, etc. as auxiliary raw materials. In this invention, (meth)acrylic means methacrylic and acrylic.

[0181] Examples of monomer components constituting the above-mentioned acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0182] Furthermore, as monomer components constituting the above-mentioned acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used along with (meth)acrylic acid and (meth)acrylic acid derivatives.

[0183] The above-mentioned acrylic resin may be a resin composed solely of (meth)acrylic components, or it may be a resin that also contains components other than (meth)acrylic components. Furthermore, the above-mentioned acrylic resin may have hydroxyl groups, carboxyl groups, silanol groups, etc.

[0184] As resin components, products from companies such as Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Kraton Chemicals, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0185] (H) Wax The rubber composition may contain wax. The wax content is preferably, for example, 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 1.5 to 10 parts by mass, per 100 parts by mass of the rubber component.

[0186] The wax used is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral waxes are preferred.

[0187] Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of petroleum-based waxes include paraffin wax, microcrystalline wax, and selected specialty waxes thereof, with paraffin wax being preferred. In this invention, the wax does not contain stearic acid.

[0188] For example, commercially available waxes from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Paramelt Co., Ltd. can be used. These waxes may be used individually or in combination of two or more types.

[0189] (ii) Anti-aging agents The rubber composition may contain an antioxidant. The amount of the antioxidant is, for example, more than 1 part by mass and less than 10 parts by mass per 100 parts by mass of the rubber component.

[0190] While not particularly limited, examples of anti-aging agents include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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), and N,N'-ditril-p-phenylenediamine. Examples include p-phenylenediamine-based antioxidants such as methyl amine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants 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 more preferred. These may be used individually or in combination of two or more.

[0191] Commercially available products include those from companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., and Flexis.

[0192] (e) Processing aids The rubber composition may contain processing aids. Examples of processing aids include metal salts (compounds in which the hydrogen atoms of an acid are replaced by metal ions), fatty acid amides, amide esters, and fatty acid esters. These may be used alone or in combination of two or more. Among these, metal salts and fatty acid amides are preferred, and metal salts are more preferred.

[0193] Examples of metals used in metal salts include alkali metals such as potassium and sodium, and alkaline earth metals such as calcium and barium. Magnesium, zinc, nickel, and molybdenum can also be used. Among these, alkali metals are preferred.

[0194] Acids used in metal salts include fatty acids such as lauric acid, myristic acid, and palmitic acid. Boric acid, carbonic acid, hydrochloric acid, nitric acid, and sulfuric acid can also be used.

[0195] Commercially available processing aids include products from companies such as Kishida Chemical Co., Ltd., Ken-ei Pharmaceutical Co., Ltd., Structol, and Performance Additives.

[0196] The content of the processing aid is preferably 1 part by mass or more, and more preferably 2 parts by mass or more, per 100 parts by mass of the rubber component. As an upper limit, for example, it is preferably 6 parts by mass or less, and more preferably 4 parts by mass or less.

[0197] (H) Lubricant (Stearic Acid) The rubber composition may contain a lubricant. Fatty acid derivative-based lubricants, such as stearic acid, are preferably used. Conventional known stearic acid products can be used; specifically, products from companies such as NOF Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries Ltd., and Chiba Fatty Acid Co., Ltd. can be used. Furthermore, products such as Structol WB16 manufactured by Structol Corporation can also be used.

[0198] The stearic acid content is preferably, for example, more than 0.5 parts by mass and less than 10.0 parts by mass per 100 parts by mass of the rubber component.

[0199] (t) Zinc oxide The rubber composition may contain zinc oxide. The zinc oxide content is, for example, more than 0.5 parts by mass and less than 10 parts by mass per 100 parts by mass of the rubber component. Conventional known zinc oxides can be used, such as products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc.

[0200] (h) Crosslinking agents and vulcanization accelerators The rubber composition preferably contains a crosslinking agent such as sulfur. The crosslinking agent content is, for example, more than 0.1 parts by mass and less than 10.0 parts by mass per 100 parts by mass of the rubber component. The sulfur content refers to the amount of pure sulfur, and if insoluble sulfur is used, it is the content excluding the oil content.

[0201] Examples of sulfur commonly used in the rubber industry include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur. These may be used individually or in combination of two or more types.

[0202] For sulfur, products from companies such as Tsurumi Chemical Industries, Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industries Co., Ltd. can be used.

[0203] Other crosslinking agents besides sulfur may be used. Specifically, for example, sulfur-containing vulcanizing agents such as Takkirol V200 from Taoka Chemical Industries, Ltd., DURALINK HTS (1,6-hexamethylene-dithiosulfate sodium dihydrate) from Flexis, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) from Lanxess, as well as organic peroxides such as dicumyl peroxide, can be used.

[0204] Furthermore, the rubber composition preferably contains a vulcanization accelerator. The amount of vulcanization accelerator is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass per 100 parts by mass of the rubber component.

[0205] Examples of vulcanization accelerators include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotrilguanidine, and orthotrilbiguanidine. These can be used individually or in combination of two or more.

[0206] (Ri) Others In addition to the components described above, the rubber composition may also contain additives commonly used in the tire industry, such as organic fillers like cellulose fibers and organic peroxides, as needed. The content of these additives is, for example, more than 0.1 parts by mass and less than 50 parts by mass per 100 parts by mass of the rubber component.

[0207] In this invention, among the materials described above, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method for obtaining the formulation of this invention from carbon dioxide, carbon dioxide may be converted directly, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0208] (2) Preparation of rubber composition for tread A rubber composition for treads can be produced by a general method, for example, a manufacturing method that includes a base mixing step of mixing rubber components with fillers such as silica, and a finish mixing step of mixing the mixture obtained in the base mixing step with a crosslinking agent.

[0209] Mixing can be carried out using known (closed) mixers such as Banbury mixers, kneaders, and open roll mixers.

[0210] The mixing temperature in the base mixing process is, for example, more than 50°C and less than 200°C, and the mixing time is, for example, more than 30 seconds and less than 30 minutes. In the base mixing process, in addition to the above components, compounding agents conventionally used in the rubber industry, such as softeners such as oils, stearic acid, zinc oxide, antioxidants, waxes, and vulcanization accelerators, may be added and mixed as needed.

[0211] In the final mixing step, the mixture obtained in the base mixing step is mixed with the crosslinking agent. The mixing temperature in the final mixing step is, for example, above room temperature but below 80°C, and the mixing time is, for example, more than 1 minute but less than 15 minutes. In the final mixing step, in addition to the above components, vulcanization accelerators, zinc oxide, etc., may be added and mixed as needed.

[0212] The rubber composition obtained as described above can then be molded into a tread by extruding it into a predetermined shape.

[0213] 3. Tire manufacturing The tire according to this embodiment can be manufactured by conventional methods. First, the rubber composition obtained above is molded into a predetermined shape to produce a tread. Next, it is combined with other rubber components on a tire molding machine to produce an unvulcanized tire.

[0214] Specifically, an inner liner as a component to ensure the airtightness of the tire, a carcass as a component to withstand the load, impact, and air pressure of the tire, a belt as a component to tighten the carcass and increase the rigidity of the tread, and a band as a component to reinforce the belt are wound around a molding drum, both ends of the carcass are fixed to both side edges, and a bead is placed as a component to fix the tire to the rim, and after forming it into a toroid shape, the tread is bonded to the center of the outer circumference and the sidewall is bonded to the radially outer side to form the side section, thereby producing an unvulcanized tire.

[0215] Subsequently, the unvulcanized tire produced as described above is heated and pressurized in a vulcanizing machine to obtain a tire. The vulcanization process can be carried out by applying known vulcanization methods. The vulcanization temperature is, for example, greater than 120°C and less than 200°C, and the vulcanization time is, for example, greater than 5 minutes and less than 15 minutes.

[0216] As mentioned earlier, the resulting tire uses PET band cords as the band cords, forms the tread using an appropriately formulated tread rubber composition, and further appropriately controls the product of the tread thickness, the amount of styrene in the SBR, and the diameter of the band cords. This allows for an improvement in overall performance, including rolling resistance, tire durability at high speeds, and handling stability.

[0217] Furthermore, the tire according to the present invention can be suitably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck / bus tire, a motorcycle tire, a racing tire, a studless tire (winter tire), an all-season tire, a run-flat tire, etc., and is particularly preferred as a passenger car tire. [Examples]

[0218] The following examples (implementations) are considered preferable for implementation, but the scope of the present invention is not limited to these examples.

[0219] We examined a tire (tire size: 215 / 60R16) consisting of a tread molded from the various compound materials listed below, as well as tire components such as bands and belts. The results calculated based on the evaluation methods described later regarding rolling resistance, tire durability at high speeds, handling stability, and overall performance are shown at the bottom of Tables 2 and 3.

[0220] 1. Preparation of rubber composition A rubber composition for the tread is prepared using the following compounding materials.

[0221] (1) Compounding materials (a) Rubber component (i) SBR-1: Modified S-SBR manufactured based on Manufacturing Example 1 described later. (Styrene content: 30% by mass, vinyl content: 25 mol%, Tg: -50℃, non-oil-based product) (b) SBR-2: Toughden 1000 manufactured by Asahi Kasei Corporation (Styrene content: 18% by mass, vinyl content: 10 mol%, Tg: -72℃, non-oil-based product) (h) SBR-3: Non-modified SBR manufactured based on manufacturing example 2 described later. (Styrene content: 24% by mass, vinyl content: 11 mol%, Tg: -63℃, non-oil-based product) (2) NR: TSR20 (e) BR: BR150B manufactured by Ube Industries (cis content: 96% by mass)

[0222] (Manufacturing Example 1) The above SBR-1 is prepared according to the following procedure. First, cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene are charged into a nitrogen-purged autoclave reactor. After adjusting the temperature of the reactor contents to 20°C, n-butyllithium is added to start polymerization. Polymerization is then carried out under adiabatic conditions, and when the maximum temperature reaches 85°C and the polymerization conversion rate reaches 99%, 1,3-butadiene is added and polymerization is carried out for a further 5 minutes, and N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane is added as a modifier to carry out the reaction. After the polymerization reaction is complete, 2,6-di-tert-butyl-p-cresol is added, the solvent is removed by steam stripping, and the mixture is dried with a hot roll to obtain SBR-1.

[0223] (Manufacturing example 2) The above SBR-3 can be obtained by modifying the manufacturing example 1 by omitting the addition of a denaturing agent and adjusting the styrene content and vinyl content.

[0224] (b) Compounding materials other than rubber components (i) Carbon Black: Show Black N220 manufactured by Cabot Japan (N2SA:111m 2 / g) (b) Silica: Ultrasil VN3 manufactured by Eponic Industries (N2SA:175m 2 / g, average primary particle diameter: 17nm) (h) Silane coupling agent: Si266 manufactured by Evonik Industries (Bis(3-triethoxysilylpropyl) disulfide) (ii) Oil: H&R Vivatec 500 (TDAE, Aromatic Process Oil) (e) Resin: SYLVARES SA85 manufactured by Arizona Chemical Corporation (α-methylstyrene resin: copolymer of α-methylstyrene and styrene, softening point 85°C) (H) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. (T) Anti-aging agent: ANTAGE 6C manufactured by Kawaguchi Chemical Industry Co., Ltd. (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) (Ch) Stearic acid: Bead stearic acid "Tsubaki" manufactured by NOF Corporation (Li) Zinc oxide: Two types of zinc oxide manufactured by Hakusuitech Co., Ltd. (Nu) Sulfur: HK-200-5 (powder sulfur) manufactured by Hosoi Chemical Industry Co., Ltd. (Ru) Vulcanization accelerator - 1: Sanseller CM-G manufactured by Sanshin Chemical Industry Co., Ltd. (N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) (Wo) Vulcanization accelerator - 2: Soxinol DG manufactured by Sumitomo Chemical Co., Ltd. (1,3-diphenylguanidine (DPG))

[0225] (2) Preparation of rubber composition for tread Based on each formulation of A to D shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerators are kneaded at 150 °C for 5 minutes to obtain a kneaded product.

[0226] Next, sulfur and vulcanization accelerators are added to the kneaded product, and it is kneaded for 5 minutes at 80 °C using an open roll to obtain rubber compositions for treads of formulations A to D.

[0227]

Table 1

[0228] 2. Molding of tire components (tread, band, belt) (1) Molding of tread Next, using the rubber composition obtained above, treads (cap treads) are molded at each thickness shown in Tables 2 and 3.

[0229] (2) Molding of band In parallel, a predetermined rubber composition for band is topped on each band cord shown in Tables 2 and 3 to mold each band.

[0230] (3) Belt forming Similarly, a predetermined rubber composition for the belt is topped on each belt code shown in Tables 2 and 3 to form each belt.

[0231] (4) Carcass forming Similarly, a predetermined rubber composition for the carcass is topped on each carcass code shown in Tables 2 and 3 to form each carcass.

[0232] 3. Tire manufacturing Next, each tread, band, belt, and carcass obtained above is bonded together with other tire members to form an unvulcanized tire, which is press-vulcanized at 170 °C for 10 minutes to manufacture test tires of Examples 1 to 5 and Comparative Examples 1 to 6.

[0233] 4. Performance evaluation test (1) Evaluation of rolling resistance Using a rolling resistance tester, the rolling resistance coefficient (RRC: Rolling Resistance Coefficient) is measured when each test tire runs on a drum at a speed of 80 km / h under the following conditions. Service rim: 16×6.5J Internal pressure: 210 kPa Load: 4.6 kN

[0234] Next, taking the result in Comparative Example 1 as 100, it is indexed based on the following formula for rolling resistance evaluation. The larger the numerical value, the more the rolling resistance is reduced. Rolling resistance evaluation = [(Result of Comparative Example 1) / (Result of test tire)] × 100

[0235] (2) Evaluation of tire durability during high-speed driving Each test tire is incorporated into a rim (size = 16×6.5J), and a tire durability test during high-speed driving is performed according to the method specified in JIS D 4230:1998 "Automobile Tires".

[0236] Next, the results in Comparative Example 1 are set to 100 and indexed based on the following formula to evaluate the tire's durability at high speeds. A higher value indicates superior tire durability at high speeds. Tire durability evaluation at high speeds =[(Results of the test tire) / (Results of Comparative Example 1)]×100

[0237] (3) Evaluation of handling stability Each test tire is mounted on all wheels of a vehicle (a domestically produced FR car with a 2000cc engine), and the vehicle is driven around a test course at speeds of 70 km / h or more. Ten test drivers each provide a subjective evaluation of the handling stability on a scale of 1 to 5 (higher numbers indicate better handling), and the total score is calculated.

[0238] Next, the results in Comparative Example 1 are set to 100 and indexed according to the following formula to evaluate handling stability. A higher numerical value indicates better handling stability at high speeds. Stability evaluation =[(Results of the test tire) / (Results of Comparative Example 1)]×100

[0239] (4) Overall evaluation Then, (1) to (3) are added together to obtain the overall evaluation.

[0240] [Table 2]

[0241] [Table 3]

[0242] Although the present invention has been described above based on embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0243] The present invention (1) is, A carcass having a carcass cord, a belt having a belt cord and provided on the outer side in the tire radial direction of the carcass, a band having a band cord and provided on the outer side in the tire radial direction of the belt, a tire comprising a tread provided on the outer side in the tire radial direction of the band, wherein the band cord is a band cord containing polyethylene terephthalate fibers, the tread is formed using a rubber composition containing more than 50 parts by mass of styrene-butadiene rubber (SBR) having a styrene content of less than 25% by mass in 100 parts by mass of the rubber component, furthermore, when the thickness of the tread is T (mm), the styrene content in the styrene-butadiene rubber is S (% by mass), and the diameter of the band cord is D (mm), it is a tire characterized by satisfying the following (Formula 1). T×S×D<80 (Formula 1)

[0244] The present invention (2) is characterized in that the band cord is a single-twist band cord formed by twisting one yarn containing polyethylene terephthalate fibers, and is the tire according to the present invention (1).

[0245] The present invention (3) is characterized in that the diameter of the band cord is more than 0.2 mm and less than 0.8 mm, and is the tire according to the present invention (2).

[0246] The present invention (4) is characterized in that the belt cord is formed by twisting one or more and four or less filaments, and is the tire according to the present invention (1).

[0247] The present invention (5) is characterized in that the structure of the belt cord is any one of a 1×1 structure, a 1×2 structure, a 1×3 structure, a 1×4 structure, and a 2+2 structure, and is the tire according to the present invention (4).

[0248] The present invention (6) is, The tire is characterized in that, when the tread is viewed in plan in the radial direction of the tire, the smaller of the angles between the circumferential direction of the tire and the longitudinal direction of the belt cord, which is the intersection angle, is less than 25 degrees, and is the tire according to (5) of the present invention.

[0249] The present invention (7) is, The tire is characterized in that the carcass is formed using carcass cords with a fineness of more than 2300 dtex, as described in (1) of the present invention.

[0250] The present invention (8) is, The tire is characterized in that the amount of styrene is 18% by mass or less, as described in (1) of the present invention.

[0251] The present invention (9) is, The tire described in (1) of the present invention is characterized in that the content of styrene-butadiene rubber in 100 parts by mass of the rubber component of the rubber composition is more than 60 parts by mass.

[0252] The present invention (10) is, The rubber composition is characterized in that it contains more than 75 parts by mass of silica per 100 parts by mass of rubber component, and is the tire described in (1) of the present invention.

[0253] The present invention (11) is, The tire described in (1) of the present invention is characterized in that the acetone extract content of the rubber composition is more than 15% by mass.

[0254] The present invention (12) is, The tire is characterized in that the thickness of the tread is greater than 6 mm, as described in (1) of the present invention.

[0255] The present invention (13) is, The tire is characterized in that the above (T×S×D) is less than 65, and is the tire described in (1) of the present invention.

[0256] The present invention (14) is, The tire is characterized in that the polyethylene terephthalate fiber is a sustainable PET fiber, as described in (1) of the present invention.

[0257] The present invention (15) is, The tire is characterized in that the sustainable PET fiber is recycled PET fiber or bio-PET fiber, as described in (14) of the present invention.

[0258] The present invention (16) is, The rubber composition is characterized by containing vegetable oil, and is the tire described in (1) of the present invention.

[0259] The present invention (17) is, The tire is characterized in that the rubber composition contains sustainable carbon black, as described in (1) of the present invention.

[0260] The present invention (18) is, The tire is characterized in that the sustainable carbon black is recycled carbon black or biomass carbon black, as described in (17) of the present invention.

[0261] The present invention (19) is, The tire is characterized in that the rubber composition contains sustainable silica, as described in (1) of the present invention.

[0262] The present invention (20) is, The tire is characterized in that the sustainable silica is biomass silica or recycled silica, as described in (19) of the present invention. [Explanation of Symbols]

[0263] 1 tire 2 tread 3 Sidewall 4 Chafers 5 Beads 6. Inner Liner 7 Carcass 8 belts 8a Belt cord 9 Filler 10 bands CL Tire Circumferential Center Line θ Intersection angle

Claims

1. A carcass equipped with a carcass cord, A belt cord is provided, and the belt is provided on the radially outer side of the carcass, A band cord is provided, and the band is provided on the radially outer side of the belt in the tire direction, A tire comprising a tread provided on the radially outer side of the band, The aforementioned band cord is a band cord containing polyethylene terephthalate fibers, The tread is formed using a rubber composition containing more than 50 parts by mass of styrene-butadiene rubber (SBR) with a styrene content of less than 25% by mass in 100 parts by mass of rubber component. Furthermore, the tire is characterized in that, when the thickness of the tread is T (mm), the amount of styrene in the styrene-butadiene rubber is S (mass%), and the diameter of the band cord is D (mm), it satisfies the following equation (Formula 1). T×S×D<80 (Formula 1)

2. The tire according to claim 1, characterized in that the band cord is a single-ply band cord made by twisting together a single yarn containing polyethylene terephthalate fibers.

3. The tire according to claim 2, characterized in that the diameter of the band cord is greater than 0.2 mm and less than 0.8 mm.

4. The tire according to claim 1, characterized in that the belt cord is formed by twisting together one to four filaments.

5. The tire according to claim 4, characterized in that the structure of the belt cord is any of a 1x1 structure, a 1x2 structure, a 1x3 structure, a 1x4 structure, or a 2+2 structure.

6. The tire according to claim 5, characterized in that, when the tread is viewed in plan in the radial direction of the tire, the smaller of the angles formed by the circumferential direction of the tire and the longitudinal direction of the belt cord, which is the intersection angle, is less than 25 degrees.

7. The tire according to claim 1, characterized in that the carcass is formed using carcass cords having a fineness of more than 2300 dtex.

8. The tire according to claim 1, characterized in that the amount of styrene is 18% by mass or less.

9. The tire according to claim 1, characterized in that the content of styrene-butadiene rubber in 100 parts by mass of the rubber component of the rubber composition is more than 60 parts by mass.

10. The tire according to claim 1, characterized in that the rubber composition contains more than 75 parts by mass of silica per 100 parts by mass of rubber component.

11. The tire according to claim 1, characterized in that the acetone extract content of the rubber composition is more than 15% by mass.

12. The tire according to claim 1, characterized in that the thickness of the tread is greater than 6 mm.

13. The tire according to claim 1, characterized in that the (T × S × D) is less than 65.

14. The tire according to claim 1, characterized in that the polyethylene terephthalate fiber is a sustainable PET fiber.

15. The tire according to claim 14, characterized in that the sustainable PET fiber is recycled PET fiber or bio-PET fiber.

16. The tire according to claim 1, characterized in that the rubber composition contains vegetable oil.

17. The tire according to claim 1, characterized in that the rubber composition contains sustainable carbon black.

18. The tire according to claim 17, characterized in that the sustainable carbon black is recycled carbon black or biomass carbon black.

19. The tire according to claim 1, characterized in that the rubber composition contains sustainable silica.

20. The tire according to claim 19, characterized in that the sustainable silica is biomass silica or recycled silica.

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