Tire

Abstract

The purpose of the present invention is to suppress heat generation during travel of a tire in which sustainable cords are used in the cord threads of a carcass cord. This tire is provided with a tread section having a tread rubber layer and a carcass section, and is characterized in that: in a carcass ply constituting the carcass section, sustainable polyester cords are used as ply cords; the product (tan [delta] * La) of the ground contact area ratio (La (%)) calculated from the ground contact area of the tread portion and the loss tangent tan [delta] measured under the conditions of a temperature of 30 DEG C, an initial strain of 5%, a dynamic strain of 1%, a frequency of 10 Hz, and deformation mode: stretching satisfies the following formula: tan [delta] * La < = 15.

Description

Technical Field

[0001] This invention relates to a tire. Background Technology

[0002] In recent years, there has been a strong demand for reducing environmental impact and saving resources. Research is underway to use bio-derived cords, recycled cords, etc. (sustainable cords) as the cords of the tire carcass ply that make up the tire carcass (for example, Patent Document 1). [Existing Technical Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-23658 Summary of the Invention [The problem the invention aims to solve]

[0004] The objective of this invention is to suppress heat generation in tires that use sustainable cords in the carcass ply cords during driving. [Methods for solving the problem]

[0005] The present invention is a tire characterized in that, It is a tire with a tread layer containing a tread rubber layer and a carcass. In the tire carcass fabric constituting the aforementioned tire carcass portion, sustainable polyester cords are used as the cords. The product of the loss tangent tanδ, measured under the conditions of 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode of tension, and the ground contact area ratio La (%) calculated from the ground contact area of ​​the aforementioned tread surface (tanδ×La), satisfies the following formula: tanδ×La≦15. [Invention Effects]

[0006] According to the present invention, it is intended to suppress the heat generation of tires using sustainable cords in the carcass ply cords during driving. Attached Figure Description

[0007]

【 Figure 1 [A schematic cross-sectional view illustrating the structure of a tire according to an embodiment of the present invention.] [Explanation of Labels in the Attached Image] 1: Tires 2: Fetal face 3: Sidewall 4: Bead area 5: Tire bead core 6: Fetus 6A: Carcass ply 6a: Inner main body 6b: Outer foldback 7: Belt layer 8: Tire bead triangle rubber C: Centerline. Detailed Implementation

[0008] [1] Features of the tire involved in this invention First, the characteristics of the tire involved in this invention will be described.

[0009] 1. Summary The tire according to the present invention comprises a tread portion having a tread rubber layer and a carcass portion, wherein sustainable polyester cord is used as the cord in the carcass ply constituting the carcass portion. Furthermore, the product (tanδ) of the loss tangent tanδ of the tread rubber layer, measured under conditions of 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode of tension, and the contact area ratio La (%) calculated from the contact area of ​​the tread portion, satisfies the following formula: tanδ×La≦15.

[0010] By having these features, as shown below, it is possible to suppress the heat generation of tires using sustainable cords in the ply cords during driving.

[0011] 2. The principle behind the performance of the tire involved in this invention The principle behind the effect of suppressing the heat generated by the tires involved in this invention during driving is as follows.

[0012] (1) Use of sustainable cords in carcass fabric In this invention, as described above, sustainable polyester cords are used as cords in the tire carcass fabric that constitutes the tire carcass.

[0013] Here, "sustainable polyester cord" refers to cords that utilize some or all of sustainable polyester, such as recycled polyester made from plastic waste like PET bottles and old clothes, or bio-polyester made from biologically derived raw materials, thus reducing environmental impact and saving resources.

[0014] However, because the raw materials and / or manufacturing methods of sustainable polyester cords differ from those of general polyethylene terephthalate cords, their performance may not be fully realized.

[0015] (2) The loss tangent and ground contact area ratio of the rubber layer on the driving surface Here, in this invention, as described above, the product of the loss tangent tanδ measured under the conditions of 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode: tension, and the ground contact area ratio La (%) calculated from the ground contact area of ​​the tread surface, (tanδ×La), satisfies the following formula: tanδ×La≦15.

[0016] The loss tangent is a viscoelastic parameter that represents the energy absorption performance. The larger the value of the loss tangent, the more energy the tire absorbs, which can easily lead to heat generation on the tread.

[0017] On the other hand, the ground contact area ratio is the ratio of the actual ground contact area to the virtual ground contact area that completely fills the grooves on the surface of the tread. When the ground contact area ratio is large, the area in contact with the road surface increases, and due to friction with the road surface, the tread is more likely to heat up.

[0018] Therefore, it is believed that when the wear tangent of the tread rubber layer is large, reducing the contact area ratio of the tread can effectively suppress the heating of the tread during driving. Conversely, it is believed that when the contact area ratio of the tread is large, reducing the wear tangent of the tread rubber layer can effectively suppress the heating of the tread during driving.

[0019] From the viewpoint of the effect of the present invention (suppressing heat generation during driving), the aforementioned (tanδ×La) is preferably 15 or less, 14 or less, 13 or less, 11 or less, or 10.5 or less. On the other hand, from another viewpoint (the viewpoint of driving stability), it is preferably 1 or more, 5 or more, 9 or more, 10 or more, 10.5 or more, 11 or more, 13 or more, 14 or more, or 15 or more.

[0020] In addition, among the above, a test piece measuring 20mm in length, 4mm in width, and 1mm in thickness, cut from the tread rubber layer of the tire with the tire circumference as the long side and the tire radial direction as the thickness direction, can be used as the object, and the loss tangent can be measured using a dynamic viscoelasticity measuring device (such as the EPLEXOR series (registered trademark) manufactured by GABO).

[0021] Furthermore, in the rubber composition constituting the driving surface rubber layer, for example, the loss tangent of the driving surface rubber layer can be appropriately adjusted by adjusting the amount of styrene, silica, carbon black and other fillers, the content of softener components, the content of resin components, etc. of the rubber components (polymers).

[0022] Specifically, for example, increasing the amount of styrene in the rubber component (polymer), increasing the amount of fillers such as silica and carbon black, reducing the content of the plasticizer component, and increasing the content of the resin component can improve the loss tangent. Conversely, reducing the amount of styrene in the polymer, reducing the amount of fillers such as silica and carbon black, increasing the content of the plasticizer component, and reducing the content of the resin component can reduce the loss tangent.

[0023] In addition, the ground contact area ratio can be determined from the ground contact shape of the tire under normal rim, normal internal pressure, and normal load conditions.

[0024] Specifically, the tire is assembled onto a standard rim, a standard internal pressure is applied, and after standing at 25°C for 24 hours, ink is applied to the tire tread surface, a standard load is applied, and the tire is pressed onto cardboard (camber angle 0°) to transfer the image onto the paper, thus obtaining the ground contact shape. The tire is then rotated 72° circumferentially to transfer the image to five locations, resulting in five ground contact shapes. These five ground contact shapes are then smoothly connected by grooves separating the contours of their respective ground contact shapes, and the resulting shapes are designated as virtual ground contact surfaces.

[0025] Furthermore, the grounding area ratio can be calculated by (average area of ​​the five grounding shapes (ink portions) transferred to the cardboard / average area of ​​the virtual grounding surface obtained from the five grounding shapes) × 100 (%).

[0026] In the above context, "standard rim" refers to the rim specified for each tire within the specification system that includes the tire's base specifications. For JATMA (Japan Automobile Tire Association), it's the standard rim with applicable dimensions listed in the JATMA YEAR BOOK; for ETRTO (The European Tyre and Rim Technical Organization), it's the "measuring rim" listed in the STANDARDS MANUAL; and for TRA (The Tire and Rim Association, Inc.), it's the "design rim" listed in the YEAR BOOK. The order of reference is JATMA, ETRTO, and TRA, and if applicable dimensions are available, those dimensions are followed. Furthermore, in cases where the specification system does not specify a tire, it refers to a rim that can be assembled and maintain internal pressure—that is, a rim with the smallest diameter and second narrowest width among rims that prevent air leakage between the rim and tire.

[0027] Meanwhile, "standard internal pressure" refers to, similarly to "standard rim," the air pressure specified for each tire within the specification system that includes the tire's base specification. For JATMA, it's the "maximum air pressure"; for ETRTO, it's the "inflation pressure"; and for TRA, it's the maximum value listed in the table "Tire Load Limits at Various Cold Inflation Pressures." Similar to standard rims, it's referenced in the order of JATMA, ETRTO, and TRA. If an applicable size is available, its specification is followed. Furthermore, for tires not specified in the specification, it refers to the standard internal pressure (of which 250 kPa or higher) for other tire sizes (specified in the specification) listed using the aforementioned standard rim as the standard rim. Additionally, when multiple standard internal pressures of 250 kPa or higher are listed, the minimum value is used.

[0028] Furthermore, "normal load" refers to the load specified for each tire in each specification within the specification system that includes the specification on which the tire is based. It indicates the maximum mass that the tire can bear. For JATMA, it refers to "maximum load capacity"; for ETRTO, it refers to "load capacity"; and for TRA, it refers to the maximum value recorded in "TIRE LOAD LIMITS ATVARIOUS COLD INFLATION PRESSURES". Similar to the aforementioned normal rim and normal internal pressure, it is referred to in the order of JATMA, ETRTO, and TRA, following their specifications. Moreover, in the case of tires not specified in the specifications, the normal load W is calculated based on the following calculations. L . V = {(Dt / 2)} 2 -(Dt / 2-Ht) 2}×π×Wt W L =0.000011×V+175 W L Normal load (kg) V: Virtual volume of the tire (mm) 3 ) Dt: Tire outer diameter Dt (mm) Ht: Tire section height (mm) Wt: Tire cross-sectional width (mm)

[0029] [2] A more preferred method in the tires involved in the present invention The tires involved in this invention can achieve even greater effects by employing the following methods.

[0030] 1. Multilayering of the tread region In this invention, the tread can be formed by only one layer of the tread rubber layer, but it can also be formed by setting a base rubber layer inside the tread rubber layer to form two layers. In addition, it can be three layers or four or more layers.

[0031] Thus, when multiplying the tread layer, the thickness of the tread rubber layer in the entire tread is preferably 10% or more, more preferably 70% or more, and even more preferably 80% or more. Furthermore, considering the suppression of heat accumulation inside the tire and the suppression of temperature rise in the tread rubber layer, the loss tangent of the base rubber layer is preferably smaller than the loss tangent of the tread rubber layer.

[0032] The ratio of the thickness of the tread rubber layer in the entire tread can be calculated by determining the thickness of the tread rubber layer and the thickness of the base rubber layer within the tread thickness. Furthermore, when grooves exist on the tire's equatorial surface, this ratio can be determined by calculating the thickness of the tread rubber layer at the center of the contact patch of the tread closest to the equatorial surface and the thickness of the base rubber layer.

[0033] Furthermore, the tread portion is the component that forms the contact patch of the tire, referring to the radially outer part of the tire that includes components such as the carcass, belt layers, and belt reinforcement layers made of fibrous materials. The thickness of the tread portion can be measured by cutting the tire radially with the bead portion aligned with the width of a standard rim.

[0034] 2. Curtain fabric and cords and their characteristics (1) Material In this invention, sustainable polyester cord is used as the fabric cord, but among various sustainable polyester cords, sustainable polyethylene terephthalate (PET) cord is preferred. Among sustainable cords with lower modulus, sustainable polyethylene terephthalate (PET) cord is preferred as the fabric cord because it is a material with high rigidity.

[0035] (2) Cord diameter As described above, in this invention, by controlling (tanδ×La) to be less than 15 (tanδ×La≦15), the heating of the tread during driving is suppressed, but the diameter of the continuous cord is also related to the heating of the tread during driving.

[0036] That is, when the diameter of the continuous cord is small, the tire tread area is easy to heat up, while when it is large, it is difficult to heat up.

[0037] Based on this, it is considered that, from the viewpoint of the effect of the present invention (suppressing heat generation during driving), taking into account the relationship between the diameter of the sustainable cord and (tanδ×La), the ratio of (tanδ×La) to the diameter F (mm) of the sustainable cord ((tanδ×La) / F) is preferably less than 26, less than 25, less than 24, less than 21.5, less than 21, less than 20.6, less than 19.2, or less than 15.5. On the other hand, it is preferably greater than 1, greater than 5, greater than 10, greater than 14.2, or greater than 15.4. Moreover, from another viewpoint (durability), it is preferably less than 15.5 or less than 14.3. Furthermore, from another viewpoint (ride comfort), it is preferably greater than 15.4, greater than 19.1, greater than 20.5, greater than 21.4, or greater than 25.

[0038] Furthermore, the diameter of the aforementioned sustainable cord is: when the circumcircle of the cross-section perpendicular to the extension direction of the cord is a perfect circle, it refers to the diameter; when it is an ellipse, it refers to the diameter of the equivalent circle (the diameter of a circle with the same cross-sectional area).

[0039] Furthermore, in this invention, the diameter of the sustainable cord is preferably 0.55 mm or more, more preferably 0.68 mm or more. On the other hand, as an upper limit, for example, it is preferably 0.98 mm or less.

[0040] (3) Content of isophthalic acid Sustainable polyester cords, made from recycled polyester cords derived from PET fibers, PET bottles, etc., may contain isophthalic acid as an impurity, potentially leading to instability in the quality of the sustainable polyester cord. Therefore, the isophthalic acid content in sustainable polyester cords is preferably less than 0.1 mol%, and particularly preferably 0.0 mol%. It is believed that this results in sustainable polyester cords of stable quality, effectively suppressing heat generation during operation. Furthermore, the isophthalic acid content in sustainable polyester cords can be determined, for example, by high-performance liquid chromatography (HPLC).

[0041] Furthermore, from the viewpoint of the effect of the present invention (suppressing heat generation during driving), the content of isophthalic acid in the sustainable polyester cord (IF, mol%) and the aforementioned relationship ((tanδ×La) / F) ((tanδ×La) / F) / (100-IF) are preferably 0.3 or less, 0.25 or less, 0.21 or less, 0.20 or less, 0.19 or less, 0.16 or less, or 0.15 or less; on the other hand, it is preferably 0.1 or more, 0.14 or more, or 0.15 or more. Moreover, from another viewpoint (durability), it is preferably 0.15 or less or 0.14 or less. Furthermore, from another viewpoint (ride comfort), it is preferably 0.14 or more, 0.15 or more, 0.19 or more, 0.20 or more, 0.21 or more, or 0.25 or more.

[0042] (4) Strength (tensile strength) The strength S (cN / dtex) of the sustainable polyester cord is preferably 6.0 cN / dtex or higher. This is because it allows the tire carcass to absorb tread deformation during high-speed driving, thus further suppressing tire heat generation during operation. More preferably, it is 6.3 cN / dtex or higher. As an upper limit, for example, it is preferably 7.0 cN / dtex or lower, more preferably 6.7 cN / dtex or lower.

[0043] In addition, the above-mentioned strength can be determined according to the method specified in "8.5 Tensile strength and elongation" of JIS L1017:2002 "Test methods for chemical fiber tire cords" (clamping interval 250 mm, tensile speed 300 mm / min).

[0044] Furthermore, in this invention, the total fineness (dtex) of the sustainable polyester cord is preferably 2200 dtex or more, more preferably 3340 dtex or more. On the other hand, as an upper limit, for example, it is preferably 6600 dtex or less.

[0045] Furthermore, the total fineness in sustainable polyester cord is the sum of the finenesses measured according to the method specified in "8.3 Positive Fineness" of JIS L1017:2002 "Test Method for Chemical Fibers Tire Cords" including the polyester fibers forming the cord. For a cord formed from one yarn, it is equivalent to the fineness of one yarn, and for a cord formed from multiple yarns, it is equivalent to the sum of the finenesses of the multiple yarns.

[0046] For example, the total fineness of the 1700dtex / 1 cord structure (which consists only of single filaments with a fineness of 1700dtex) is 1700dtex, and the total fineness of the 1700dtex / 2 cord structure (which consists of two single filaments with a fineness of 1700dtex twisted together) is 3400dtex.

[0047] Furthermore, in this invention, the strength S (cN / dtex) of the sustainable polyester cord, the content of isophthalic acid IF (mol%), and the loss tangent tanδ of the rubber layer on the running surface preferably satisfy the following formula. S×IF / tanδ≧50

[0048] Therefore, it is believed that while controlling manufacturing costs, a longer tire life can be achieved. More preferably, the value is 55 or higher, and even more preferably 60 or higher. As an upper limit, there is no particular limitation; for example, it is preferably less than 200, and more preferably less than 150.

[0049] (5) Density and strength The product of the strength S (cN / dtex) of the sustainable polyester cord and the number of cords (warp density) D (cords / 5cm) present in a 5cm width in the vertical direction relative to the length of the cords (sustainable polyester cords) in the tread (S×D) is preferably 160 or more (S×D≧160). It is believed that this allows for sufficient absorption of tread deformation during high-speed driving in the tire carcass, thereby further suppressing tire heat generation during driving. More preferably, it is 190 or more, 192 or more, or 214 or more. On the other hand, from another viewpoint (durability viewpoint), it is preferably 250 or less, 220 or less, 215 or less, or 193 or less.

[0050] Furthermore, in this invention, the warp density of the curtain cords is preferably 32 cords / 5cm or more.

[0051] (6) Intermediate elongation and warp density The intermediate elongation E (%) in a specified load L (cN / dtex) of sustainable polyester cord preferably satisfies the following formula between the warp density D (strands / 5cm) mentioned above. 12≦L×D / E≦20

[0052] It is believed that, by properly controlling (L×D / E), the deformation of the tread portion during high-speed driving can be adequately absorbed in the tire carcass, thus further suppressing tire heat generation during driving. As a lower limit, 13.6 or more, 14 or more, 14.8 or more, and 14.9 or more are more preferred. On the other hand, as an upper limit, 15 or less, 14.9 or more, and 13.7 or less are more preferred.

[0053] In addition, the aforementioned intermediate elongation can be determined according to the test method of "elongation under constant load" in JIS L1017:2002 "Test method for chemical fiber tire cord".

[0054] Specifically, the intermediate elongation when the specified load L mentioned in the next paragraph is set to 2.0 cN / dtex can be determined by the following method: a cord is collected from the vulcanized tire, and a tensile test is carried out under the conditions of 100±2℃, clamping interval of 250mm, and tensile speed of 300±20mm / min. The elongation (%) at the point corresponding to the load of 2.0 cN / dtex on the load-tensile curve is then determined.

[0055] Furthermore, in this invention, the intermediate elongation rate when the specified load L is set to 2.0 cN / dtex is preferably 4.3% or less. On the other hand, as an upper limit, for example, it is preferably 4.7% or less.

[0056] (7) Elongation at break The elongation at break (%) of the sustainable polyester cord is preferably 10% or more. This is because, since the tread deformation during high-speed driving can be adequately absorbed in the tire carcass, tire heat generation during driving can be further suppressed. More preferably, it is 12% or more, and even more preferably 13% or more.

[0057] In addition, the above-mentioned elongation at break can be determined according to the method specified in "8.5 Tensile strength and elongation" of JIS L1017:2002 "Test methods for chemical fiber tire cords" (clamping interval 250 mm, tensile speed 300 mm / min).

[0058] (8) Strength retention rate in damp heat resistance The moisture and heat resistance strength retention rate (%) of the sustainable polyester cord is preferably 80% or more. This is because it is believed that this can suppress heat generation during operation for a long period. More preferably, it is 85% or more, and even more preferably 90% or more.

[0059] Furthermore, the aforementioned strength retention rate for resistance to damp heat can be calculated by determining the ratio of the strength after treatment with saturated water vapor at 135°C for 48 hours (damp heat treatment) to the strength before treatment.

[0060] 3. Aspect ratio of cross-section The aspect ratio is the ratio of the tire's height to its width. Increasing the aspect ratio reduces the contact area with the road surface, thus suppressing heat generation in the tire tread. However, excessively increasing the aspect ratio may reduce driving stability.

[0061] Taking these points into consideration, the aspect ratio of the tires involved in this invention is preferably 30% or more. As an upper limit, it is preferably 60% or less, and more preferably 55% or less.

[0062] Furthermore, the aforementioned section height-to-width ratio (%) can be calculated using the tire's section height Ht (mm), section width Wt (mm), tire outer diameter Dt (mm), and rim diameter R (mm) when the internal pressure is set to 250 kPa, by the following formula. Cross-sectional height-to-width ratio (%) = (Ht / Wt) × 100 (%) Ht=(Dt-R) / 2

[0063] 4. Grounding area ratio and loss tangent As described above, in this invention, tanδ×La is controlled to be relatively small to 15 or less (tanδ×La≦15), but as a specific ground contact area ratio La when assembled on a regular rim and set to regular internal pressure, it is preferably 55% or more, more preferably 60% or more. As an upper limit, it is preferably 75% or less, more preferably 70% or less, and even more preferably 65% ​​or less.

[0064] Furthermore, the loss tangent tanδ of the rubber layer on the running surface at a temperature of 30°C is preferably 0.15 or higher. On the other hand, as an upper limit, it is preferably 0.2 or lower, for example.

[0065] [3] Implementation The present invention will be described in detail below based on the embodiments.

[0066] 1. The tires involved in this implementation method Figure 1 This is a schematic cross-sectional view illustrating the structure of the tire involved in this embodiment, showing a tire meridian cross-section including the axis of rotation in the normal state of the tire.

[0067] like Figure 1 As shown, the tire 1 includes: a tire body 6 extending from the tread portion 2 through the sidewall portion 3 to the bead portion 4, and a belt layer 7 disposed on the radially outer side of the tire body 6 and the inner side of the tread portion 2. Furthermore, C is the centerline.

[0068] The fetal body consists of at least one piece ( Figure 1 The tire carcass is composed of one piece of tire carcass cord 6A, which is secured by folding the bead core 5 of the bead portion 4 from the inside to the outside through the sidewall portion 3 from the tread portion 2. Furthermore, Figure 1 In the middle, 6a is the inner main body of the tire carcass cord 6A, and 6b is the outer fold-back part. Between the inner main body 6a and the outer fold-back part 6b, for example, a bead triangle rubber 8 extending radially outward from the bead core 5 is provided.

[0069] In this embodiment, the tire carcass cord 6A uses sustainable polyester cord as the cord, and is constructed by covering both sides of the sustainable polyester cord arrangement with a specified density with coated rubber.

[0070] By using such carcass plies to form the carcass portion, and by appropriately controlling the loss tangent of the tread rubber layer and the contact area ratio of the tread portion, it is possible to suppress the heat generation of tires using sustainable cords in the plies during driving.

[0071] 2. Rubber composition forming the driving surface rubber layer (driving surface rubber composition) In this embodiment, the driving surface rubber composition can be obtained by mixing various compounding materials such as rubber components, reinforcing agents, antioxidants, oils, resin materials, and antioxidants.

[0072] (1) Compound materials (a) Rubber composition There are no particular limitations on the rubber component. For example, isoprene-based rubbers (natural rubber (NR), isoprene rubber (IR), etc.), styrene-butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and other diene-based rubbers can be used. These can be used alone or in combination with two or more. In this invention, it is preferred to use SBR in combination with BR or isoprene-based rubbers.

[0073] (①)SBR The weight-average molecular weight of the SBR is, for example, greater than 100,000 and less than 2,000,000. The styrene content of the SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and even more preferably greater than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and even more preferably less than 30% by mass. The vinyl content (1,2-bonded butadiene unit weight) of the SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and even more preferably greater 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. Furthermore, the structural identification of the SBR (determination of styrene content and vinyl content) can be performed, for example, using an apparatus from the JNM-ECA series manufactured by Nippon Electronics Corporation.

[0074] There are no particular limitations on the type of SBR used; for example, emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR) can be used. The SBR can be any type of unmodified or modified SBR. Furthermore, hydrogenated SBRs can be used, obtained by hydrogenating the butadiene portion of the SBR. Hydrogenated SBRs can also be obtained by subsequently hydrogenating the BR portion of the SBR, or by copolymerizing styrene, ethylene, and butadiene to obtain the same structure.

[0075] As a modified SBR, an SBR having functional groups that interact with fillers such as silica is preferred. Examples include end-modified SBRs (end-modified SBRs with the aforementioned functional groups at the end) which are modified by using a compound (modifier) ​​having the aforementioned functional groups on at least one side of the SBR, main-chain modified SBRs with the aforementioned functional groups in the main chain, main-chain end-modified SBRs with the aforementioned functional groups in both the main chain and the end (e.g., main-chain end-modified SBRs with the aforementioned functional groups in the main chain and at least one end modified by the aforementioned modifier), modified (coupled) by a polyfunctional compound having two or more epoxy groups in the molecule, and end-modified SBRs with hydroxyl or epoxy groups introduced.

[0076] Examples of the aforementioned functional groups include, for example, amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazo, urea, ether, carbonyl, oxycarbonyl, mercapto, thioether, dithioether, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imide, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxygen, and epoxy groups. Furthermore, these functional groups may also have substituents.

[0077] Furthermore, as a modified SBR, for example, an SBR modified by a compound (modifier) ​​represented by the following formula can be used.

[0078]

Chemical Formula 1

[0079] In addition, R in the formula 1 R 2 and R 3 Same or different, indicating alkyl, alkoxy, siloxy, acetal, carboxyl (-COOH), mercapto (-SH) or derivatives thereof. R 4 and R 5 Same or different, indicating hydrogen atoms or alkyl groups. R 4 and R 5 It can also bond and form a ring structure with nitrogen atoms. n represents an integer.

[0080] As a modified SBR modified by the compound (modifier) ​​represented by the above formula, an SBR modified by the polymerization end (active end) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the above formula can be used (modified SBR, etc. as described in Japanese Patent Application Publication No. 2010-111753).

[0081] As R 1 R 2 and R 3Preferably, it is an alkoxy group (preferably with 1 to 8 carbon atoms, more preferably an alkoxy group with 1 to 4 carbon atoms). As R 4 and R 5 Preferably, it is 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 even more preferably 3. Furthermore, R 4 and R 5 When the bond combines with a nitrogen atom to form a ring structure, a 4- to 8-membered ring is preferred. Furthermore, alkoxy groups also include cycloalkoxy groups (such as cyclohexyloxy) and aryloxy groups (such as phenoxy and benzyloxy).

[0082] Specific examples of the aforementioned modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These can be used individually or in combination of two or more.

[0083] In addition, modified SBRs can also be used as modified SBRs by the following compounds (modifiers). Examples of modifiers include, in addition to polyglycidyl ethers of polyols such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenolic groups such as bisphenol A diglycidyl ether; polyepoxide compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxide liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidyl aniline, N,N'... -Diglycidyl-4-glycidyloxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-phenylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-diaminomethylcyclohexane, and other diglycidylamino compounds; bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinocarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, N,N-diethylcarbamoyl chloride, and other amino-containing acyl chlorides; 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3- Silane compounds containing epoxy groups, such as glycidyloxypropyl (-pentamethyldisiloxane); (trimethylsilyl)[3-(trimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl] sulfide, (trimethylsilane) Silane compounds containing thioether groups, such as (trimethylsilyl)[3-(methyldipropoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted aziridine compounds, such as ethyleneimine and propyleneimine; alkoxysilanes, such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethyltriethoxysilane.4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone, and other (thio)benzophenone compounds having amino and / or substituted amino groups; 4-N,N-dimethylaminobenzophenone Formaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde, and other benzaldehyde compounds containing amino groups and / or substituted amino groups; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone, and other N-substituted pyrrolidones; N-methyl-2-piperidinone, N-vinyl-2-piperidinone, N-phenyl-2-piperidinone, and other N-substituted pyrrolidones. In addition to N-substituted piperidinones such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam, other N-substituted lactams include 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, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethylidene urea, 1,3-divinylethylidene urea, 1,3-diethyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Furthermore, modification based on the above compounds (modifiers) can be carried out by known methods.

[0084] As an SBR (Self-Borne Blender), for example, SBR manufactured / sold by companies such as Sumitomo Chemical Co., Ltd., ENEOS MATERIAL Co., Ltd., Asahi Kasei Corporation, and Zeon Corporation of Japan can be used. Furthermore, SBR can be used alone or in combination of two or more types.

[0085] The SBR content in 100 parts by weight of the rubber component is preferably 60 parts by weight or more, more preferably 70 parts by weight or more. As an upper limit, for example, it is preferably 90 parts by weight or less, more preferably 80 parts by weight or less.

[0086] (②)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 less than 98% by mass. The trans content of BR is, for example, greater than 1% by mass and less than 60% by mass. Furthermore, the cis content can be determined by infrared absorption spectroscopy.

[0087] There are no particular limitations on the type of BR used; BR with high cis content (cis content of 90% or more), BR with low cis content, and BR containing syndiotactic polybutadiene crystals can be used. BR can be any type of unmodified BR or modified BR. As a modified BR, for example, BR modified by a compound (modifier) ​​represented by the following formula can be used.

[0088] [Chemical Formula 2]

[0089] In addition, R in the formula 1 R 2 and R 3 Represents the same or different alkyl, alkoxy, siloxy, acetal, carboxyl (-COOH), mercapto (-SH) groups, or their derivatives. R 4 and R 5 Indicates the same or different hydrogen atoms or alkyl groups. R 4 and R 5 It can also bond and form a ring structure with nitrogen atoms. n represents an integer.

[0090] Examples of modified BRs modified by compounds (modifiers) represented by the above formulas include BRs whose polymerization ends (active ends) are modified by compounds represented by the above formulas.

[0091] As R 1 R 2 and R 3 Preferably, it is an alkoxy group (preferably an alkoxy group with 1 to 8 carbon atoms, more preferably an alkoxy group with 1 to 4 carbon atoms). As R 4 and R 5 Preferably, it is 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 even more preferably 3. Furthermore, R 4 and R 5 When the bond combines with a nitrogen atom to form a ring structure, a 4- to 8-membered ring is preferred. Furthermore, alkoxy groups also include cycloalkoxy groups (such as cyclohexyloxy) and aryloxy groups (such as phenoxy and benzyloxy).

[0092] Specific examples of the aforementioned modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These can be used alone or in combination of two or more.

[0093] In addition, modified BRs can also be used as modified BRs by the following compounds (modifiers). As modifiers, for example, polyglycidyl ethers of polyols such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenolic groups such as bisphenol A diglycidyl ether; polyepoxide compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxide liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidyl aniline, N,N' -Diglycidyl-4-glycidyloxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-phenylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-diaminomethylcyclohexane, and other diglycidylamino compounds; bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinocarbamoyl chloride, 1-pyrrolidinecarbamoyl chloride, N,N-dimethylcarbamoyl chloride, N,N-diethylcarbamoyl chloride, and other amino-containing acyl chlorides; 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3 Silane compounds containing epoxy groups, such as (-glycidoxypropyl)-pentamethyldisiloxane; (trimethylsilyl)[3-(trimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl] sulfide, (trimethylsilyl][3-(methyldimethoxysilyl)propyl] sulfide, (trimethylsilyl][3-(methyldiethoxysilyl)propyl] sulfide, (trimethylsilyl) Silane compounds containing thioether groups, such as alkyl(3-(methyldipropoxysilyl)propyl)thioether and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]thioether; N-substituted aziridine compounds, such as ethyleneimine and propyleneimine; alkoxysilanes, such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethyltriethoxysilane.4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone, and other (thio)benzophenone compounds having amino and / or substituted amino groups; 4-N,N-dimethylaminobenzophenone Formaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde, and other benzaldehyde compounds containing amino groups and / or substituted amino groups; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone, and other N-substituted pyrrolidones; N-methyl-2-piperidinone, N-vinyl-2-piperidinone, N-phenyl-2-piperidinone, and other N-substituted pyrrolidones. In addition to N-substituted piperidinones such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam, other N-substituted lactams include 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, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethylidene urea, 1,3-divinylethylidene urea, 1,3-diethyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Furthermore, modification based on the above compounds (modifiers) can be carried out by known methods. Moreover, these modified BRs can be used alone or in combination of two or more.

[0094] As a BR (Brandinger), products from companies such as Ube Industries, Inc., Enos Manufacturing Co., Ltd., Asahi Kasei Corporation, and Zeon Corporation can be used.

[0095] The BR content in 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 15 parts by weight or more. On the other hand, it is preferably 30 parts by weight or less, more preferably 25 parts by weight or less, and even more preferably 20 parts by weight or less.

[0096] (③) Isoprene rubber As isoprene-based rubbers, examples include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR.

[0097] For example, substances commonly used in the tire industry, such as SIR20, RSS#3, TSR20, and SVR-L, can be used as NR. For IR, there are no particular limitations; for example, substances commonly used in the tire industry, such as IR2200, can be used. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These can be used individually or in combination of two or more.

[0098] The content of isoprene-based rubber in 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 15 parts by weight or more. On the other hand, it is preferably 30 parts by weight or less, more preferably 25 parts by weight or less, and even more preferably 20 parts by weight or less.

[0099] (④) Other rubber components In the tread rubber composition, as other rubber components, it may also contain rubbers (polymers) commonly used in tire manufacturing, such as nitrile rubber (NBR), as needed.

[0100] In addition, the raw materials (monomers) of the aforementioned synthetic rubbers such as SBR and BR can be substances derived from underground resources such as petroleum and natural gas, or substances recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0101] The monomer obtained through recycling (recycled monomer) is not particularly limited, and examples include recycled isoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds are not particularly limited, and examples include styrene. Preferably, recycled isoprene, butadiene, and / or recycled styrene are used as raw materials.

[0102] There are no particular limitations on the manufacturing method of the recycled monomer. For example, synthetic naphtha derived from recycled petroleum products obtained by pyrolyzing rubber products such as tires can be cited. Furthermore, there are no particular limitations on the manufacturing method of naphtha derived from recycled petroleum products. For example, rubber products such as tires can be pyrolyzed under high temperature and pressure, microwave pyrolysis can be used, or extraction can be performed after mechanical crushing.

[0103] Furthermore, the raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR can also be substances derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. There are no particular limitations on biomass; for example, substances derived from agricultural, forestry, and aquatic products, sugar, sawdust, plant residues after the extraction of useful components, plant-derived ethanol, and biomass petroleum naphtha can be listed.

[0104] The term "biomass monomer" is not particularly limited and can include butadiene derived from biomass, aromatic vinyl compounds derived from biomass, etc. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include styrene, etc. Furthermore, the method of manufacturing biomass monomers is not particularly limited; for example, substances obtained through biological and / or chemical and / or physical conversions of plants and animals can be listed. As a biological conversion, microbial fermentation is representative; as a chemical and / or physical conversion, conversions based on catalysts, high-temperature conversions, high-pressure conversions, electromagnetic wave conversions, supercritical fluid conversions, and combinations thereof can be listed.

[0105] The term "biomass polymer" is not particularly limited to polymers synthesized from biomass monomer components, but examples include polybutadiene rubber synthesized from butadiene derived from biomass, and aromatic vinyl / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl compounds derived from biomass. Examples of such aromatic vinyl / butadiene copolymers include styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass.

[0106] Whether the polymer's raw materials are derived from biomass can be determined by the pMC (percent Modern Carbon) measured according to ASTM D6866-10.

[0107] pMC refers to: the sample 14 C concentration relative to standard modern carbon (modern standard reference) 14 The C concentration ratio is a value used as an indicator of the biomass ratio of a compound. The significance of this value is explained below.

[0108] One mole of carbon atoms (6.02 × 10⁻⁶) 23 Of these, approximately one trillionth exists, which is about 6.02 × 10⁻⁶. 11 indivual 14 C. 14 C is known as a radioactive isotope with a half-life of 5730 years. 14Carbon (C) decreases systematically. All of this decays over a period of 226,000 years. Therefore, fossil fuels such as coal, oil, and natural gas, which are believed to have been immobilized by plants and other organisms in the atmosphere for over 226,000 years, contained carbon dioxide at the time of initial immobilization. 14 All carbon (C) decays. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain absolutely no carbon. 14 Therefore, the chemicals produced using these fossil fuels as raw materials also contain absolutely no carbon (C). 14 C element.

[0109] on the other hand, 14 Carbon is continuously generated in the atmosphere through nuclear reactions caused by cosmic rays, reaching a balance with the reduction based on radioactive decay in Earth's atmospheric environment. 14 The amount of C is constant. Therefore, in the current environment, the matter originating from biomass resources in the material cycle... 14 The C concentration, as described above, is approximately 1 × 10⁻⁶ relative to all C atoms. -12 These values ​​are approximately mol%. Therefore, by using the differences between these values, the biomass percentage in a compound can be calculated.

[0110] Typically, the 14 C was determined as described below. Accelerator mass spectrometry based on a tandem accelerator was used for the determination. 13 C concentration ( 13 C / 12 C) 14 C concentration ( 14 C / 12 C) Determination. During the determination, as... 14 The standard for C concentration in modern carbon is based on the carbon cycling in nature as of 1950. 14 C concentration. As a specific standard substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) was used. The radioactivity of carbon in this oxalic acid (carbon content per gram of carbon) was determined. 14 The radioactivity intensity of carbon (C) is classified according to its carbon isotopes. 13 The C-correction is a fixed value, using the value with attenuation correction applied from 1950 to the date of measurement as the standard. 14 The C concentration value (100%) is used. The ratio of this value to the value of the actual sample measured is the pMC value.

[0111] Therefore, if the rubber is made from materials 100% derived from biomass, then despite regional differences, it is expected to have a value of around 110 pMC, since it is generally not 100% biomass under normal conditions. On the other hand, for chemicals derived from fossil fuels such as petroleum, the measured value... 14 At a C concentration, it will exhibit a value of approximately 0 pMC (e.g., 0.3 pMC). This value corresponds to the aforementioned biomass ratio of 0%.

[0112] In summary, from an environmental protection perspective, it is preferable to use rubber materials with high pMC values, i.e., rubber materials with high biomass ratios, in rubber compositions.

[0113] (b) Compounds other than rubber components (①) Filler The rubber composition for the driving surface preferably contains silica and carbon black as reinforcing agents, but may also contain other fillers as needed, such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, vulcanized rubber granules (rubber powder), etc. Furthermore, when using silica, it is preferable to use it in conjunction with a silane coupling agent.

[0114] (i) Silicon dioxide Because silica has OH groups on its surface, it can capture ozone, thus improving ozone resistance and tire durability. Furthermore, by containing up to 75 parts by mass, hydrogen bonds are formed between silica surfaces, and it interacts with rubber components.

[0115] From the viewpoint of achieving good durability, the BET specific surface area of ​​silica is preferably greater than 100 m². 2 / g, more preferably greater than 130m 2 / g. On the other hand, it is preferable to have less than 250m. 2 / g, more preferably less than 200m 2 / g, more preferably 175m 2 / g or less. Furthermore, the BET specific surface area mentioned above is the N2SA value determined by the BET method according to ASTM D3037-93.

[0116] There are no particular limitations on the type of silica used. For example, silica prepared by dry process (anhydrous silica) or silica prepared by wet process (hydrated silica) commonly used in the tire industry can be used. As commercially available products, products from companies such as Evonik Industries, Roudia, Tosoh Silicon Chemicals, Solvay Japan, and Tokuyama Corporation can be used.

[0117] There are no particular limitations on the raw materials used for silica. For example, it can be derived from minerals such as quartz, or from biological sources such as rice husks (e.g., silica derived from biomass materials such as rice husks), or silica recovered from silica-containing products. Among these, hydrous silica prepared by a wet process is preferred due to its higher silanol group content. These silicas can be used individually or in combination of two or more types.

[0118] Silica obtained from biomass materials (biomass silica), for example, can be obtained by extracting silicates from rice husk ash obtained by burning rice husks using sodium hydroxide solution. The silicates are then reacted with sulfuric acid in the same way as conventional wet silica. The resulting silica precipitate is filtered, washed with water, dried, and pulverized.

[0119] Silica recovered from products containing silica (recycled silica) can be, for example, silica recovered from products containing silica such as electronic components like semiconductors, tires, desiccants, and filter materials such as diatomaceous earth. Furthermore, the method of recovery is not particularly limited, and examples include pyrolysis and electromagnetic wave-based pyrolysis. Of these, silica recovered from electronic components like semiconductors or tires is preferred.

[0120] If silicon dioxide crystallizes, it becomes insoluble in water and cannot utilize the silicic acid that is its component. By managing the combustion temperature and combustion time, the crystallization of silicon dioxide in rice husk ash can be suppressed (see Japanese Patent Application Publication No. 2009-2594, Akita Prefectural University Online Journal B (see Akita Prefectural University Web Journal B) / 2019, vol.6, pp.216-222, etc.).

[0121] Amorphous silica extracted from rice husks can be obtained from commercially available materials such as those from Wilmar.

[0122] Furthermore, these silicas can be used alone or in combination with two or more types. Moreover, from an environmental protection perspective, the use of sustainable silicas such as biomass silica derived from biomass or recycled silica obtained from recycled old products and waste materials is preferred.

[0123] The silica content relative to 100 parts by weight of the rubber component is preferably greater than 60 parts by weight, more preferably 70 parts by weight or more, and even more preferably 80 parts by weight or more. As an upper limit, for example, it is preferably 120 parts by weight or less, more preferably 100 parts by weight or less.

[0124] (ii) Silane coupling agents When using silica, in order to improve the dispersibility of silica and improve mechanical properties and formability through reaction with silica, it is preferable to use it in combination with a silane coupling agent.

[0125] As a silane coupling agent, there are no particular limitations; examples include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, and bis(4-trimethoxysilyl... Butyl) trisulfide, 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-dimethylthioaminomethyl Sulfide systems including acyl tetrasulfides, 2-triethoxysilyl ethyl-N,N-dimethylthiocarbamoyl tetrasulfides, and 3-triethoxysilyl propyl methacrylate monosulfides; thiol-based systems including 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based systems including vinyltriethoxysilane and vinyltrimethoxysilane; 3-aminopropyltriethoxysilane... Amino-based silanes such as oxysilanes and 3-aminopropyltrimethoxysilane; glycidyl oxysilanes such as γ-glycidyloxypropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane; nitro-based silanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chlorinated silanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc., are preferred among these, especially silane coupling agents with thiocarbonyl groups such as NXT mentioned above. These can be used alone or in combination of two or more.

[0126] As silane coupling agents, products from companies such as Evonik Industries, Momentive, Shin-Etsu Silicon, Tokyo Chemical Industries, Azmax, and Toray Dow Corning can be used.

[0127] The content of the silane coupling agent relative to 100 parts by weight of silicon dioxide is preferably greater than 3 parts by weight, more preferably 5 parts by weight or more, even more preferably 7 parts by weight or more, and even more preferably 8 parts by weight or more. As an upper limit, it is preferably less than 15 parts by weight, more preferably 12 parts by weight or less, and even more preferably 9 parts by weight or less.

[0128] (iii) Carbon black Carbon black is preferably used to improve the tire's resistance to crack growth, durability, and resistance to UV degradation.

[0129] From the viewpoint of reinforcing rubber, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably, for example, 30 m² / s. 2 / g or more, preferably 50m 2 / g or more, further preferably 60m 2 / g or more. On the other hand, from the viewpoint of pyrogenicity, 250m is preferred. 2 / g or less, more preferably 150m 2 / g or less, more preferably 120m 2 / g or less, more preferably 115m 2 / g or less. Furthermore, the nitrogen adsorption specific surface area of ​​carbon black was determined according to ASTM D4820-93.

[0130] From the viewpoint of rubber rigidity, the dibutyl phthalate (DBP) absorption of carbon black is preferably 50 ml / 100g or more, more preferably 100 ml / 100g or more. On the other hand, from the viewpoint of rubber deformation adaptability, it is preferably 250 ml / 100g or less, more preferably 150 ml / 100g or less. Furthermore, the DBP absorption of carbon black is determined according to ASTM D2414-93.

[0131] As for carbon black, there are no particular limitations. Examples include furnace black (such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF); acetylene black; thermal black (such as FT and MT); and channel black (such as EPC, MPC, and CC). Additionally, as product codes, examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These can be used individually or in combination.

[0132] Besides mineral oil, carbon black can also be made from biomass materials such as lignin and vegetable oil, or from recycled materials such as thermal cracking oil obtained by thermally cracking waste tires and other rubber products. From an environmental protection perspective, sustainable carbon black, such as biomass carbon black made from biomass materials or recycled carbon black made from recycled materials such as old products and waste, is preferred.

[0133] In addition, carbon black can be manufactured by combustion-based methods such as furnace methods, hydrothermal carbonization (HTC) methods, or thermal decomposition methods such as thermal cracking carbon black methods based on methane.

[0134] As commercially available products, those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Nippon Steel Carbon Black Co., Ltd., Columbia Carbon Co., Ltd., etc., can be used. These can be used alone or in combination of two or more.

[0135] The content of carbon black relative to 100 parts by weight of the rubber component is preferably 3 parts by weight or more, more preferably 5 parts by weight or more. As an upper limit, for example, it is preferably 15 parts by weight or less, more preferably 10 parts by weight or less.

[0136] (iv) Other fillers In addition to carbon black and silica, 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. These contents, relative to 100 parts by weight of the rubber component, are, for example, greater than 0.1 parts by weight and less than 150 parts by weight.

[0137] (②) Plasticizer (softener) components In the rubber composition for driving surfaces, from the viewpoint of imparting plasticity to the rubber components during mixing and properly dispersing the powder material, it is preferable to use a softener (plasticizer) component as needed. Furthermore, the softener component here refers to both a softener that is liquid at 25°C and a softener that is solid at 25°C.

[0138] Examples of plasticizers include resin components, oils, liquid polymers, and ester-based plasticizers. These plasticizers can be derived from mineral resources such as petroleum and natural gas, biomass, or petroleum naphtha recycled from rubber and non-rubber products. Furthermore, low-molecular-weight hydrocarbon components obtained through the thermal cracking and extraction of used tires and products containing various components can also be used as plasticizers. Among these, plasticizers derived from biomass or recycled materials are preferred as sustainable plasticizers.

[0139] Furthermore, these softeners can be used alone or in combination of two or more. The content of the softener component relative to 100 parts by weight of the rubber component is preferably 20 parts by weight or more, more preferably 30 parts by weight or more. As an upper limit, for example, it is preferably 80 parts by weight or less, more preferably 70 parts by weight or less, and even more preferably 65 parts by weight or less. In addition, the content of the softener component also includes the amount of oil contained in the rubber (oil-extended rubber), etc.

[0140] (i)Oil Examples of oils include mineral oils, vegetable oils, and animal oils. Furthermore, from a life cycle assessment perspective, waste oil from rubber mixers or engines, or refined waste cooking oil from restaurants, can also be used.

[0141] (i-1) mineral oil In this manual, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oils include paraffinic oils, naphthenic oils, and aromatic oils.

[0142] 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).

[0143] Furthermore, due to environmental countermeasures, oils with lower polycyclic aromatic compounds (PCA) content can also be used. Examples of such low PCA content oils include MES, TDAE, and heavy cycloalkane oils.

[0144] Commercially available mineral oils include, for example, paraffinic, aromatic, and naphthenic oils. Products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Oil & Chemical Co., Ltd., ENEOS Co., Ltd., Orisoy Corporation, H&R Corporation, Toyokuni Oil Co., Ltd., Showa Shell Oil Co., Ltd., and Fuji Kosan Co., Ltd. can be used. These can be used alone or in combination of two or more.

[0145] (i-2) Vegetable oils Examples of vegetable oils include flaxseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla seed oil, castor oil, tung oil, pine oil, pine tar, sunflower seed oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and wood wax.

[0146] Furthermore, examples of vegetable oils include refined oils (such as salad oil) obtained by refining the aforementioned oils, transesterified oils obtained by transesterification of the aforementioned oils, hydrogenated oils obtained by hydrogenation of the aforementioned oils, thermally polymerized oils obtained by thermal polymerization of the aforementioned oils, oxidatively polymerized oils obtained by oxidation of the aforementioned oils, and waste edible oils recovered from oils used as edible oils, etc. In addition, vegetable oils can be liquid or solid at room temperature (25°C). One type can be used alone, or two or more types can be used in combination.

[0147] As a vegetable oil, it is preferable to contain acylglycerol, more preferably triacylglycerol. Furthermore, acylglycerol refers to a compound in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. There is no particular limitation on the acylglycerol; it can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Further, acylglycerol can be a monomer, a dimer, or a polymer of more than one trimer. Moreover, acylglycerols of more than one dimer can be obtained by thermal polymerization, oxidative polymerization, etc. Furthermore, acylglycerol can be liquid or solid at room temperature (25°C).

[0148] There is no particular limitation on the method for confirming the presence of acylglycerol in a rubber composition; it can be achieved through... 1 Confirmed by ¹H-NMR determination. For example, a rubber composition containing triacylglycerol was impregnated in deuterated chloroform at room temperature (25°C) for 24 hours. After removing the rubber composition, the concentration was determined at room temperature. 1 H-NMR, with the tetramethylsilane (TMS) signal set to 0.00 ppm, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm. These signals were presumed to originate from hydrogen atoms bonded to the carbon atom adjacent to the oxygen atom of the ester group, thus confirming the presence of acylglycerol. Furthermore, "around" here refers to a range of ±0.10 ppm.

[0149] Furthermore, as a fatty acid, there are no particular limitations; it can be either an unsaturated or saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, or polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0150] Among these fatty acids, fatty acids with fewer double bonds are preferred, namely saturated fatty acids or monounsaturated fatty acids, with oleic acid being the most preferred. As a vegetable oil containing such fatty acids, for example, vegetable oils containing saturated fatty acids or monounsaturated fatty acids can be used, or vegetable oils that have undergone transesterification or other modifications can be used. Furthermore, to produce such vegetable oils containing fatty acids, plants can be improved through variety improvement, gene recombination, gene editing, etc.

[0151] As a vegetable oil, for example, commercially available substances from companies such as Idemitsu Kosan Co., Ltd., Sankyo Oil & Chemical Co., Ltd., ENEOS Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nissin Orisoy Group Co., Ltd. can be used.

[0152] (ii) Liquid rubber Liquid rubber refers to polymers that are liquid at room temperature (25°C) and can be extracted from vulcanized tires using acetone. Examples of liquid rubber include farnesene polymers, liquid diene polymers, and their hydrides.

[0153] Farnesene polymers are polymers obtained by polymerizing farnesenes and possess structural units based on farnesenes. Farnesenes contain isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecathetene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecathetene).

[0154] Farnesene polymers can be homopolymers of farnesene (farnesene homopolymers) or copolymers of farnesene and vinyl monomers (farnesene-vinyl monomer copolymers).

[0155] 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).

[0156] The weight-average molecular weight (Mw) of polystyrene-based liquid diene polymers, determined by gel permeation chromatography (GPC), for example, greater than 1.0 × 10⁻⁶. 3 Less than 2.0×10 5 Here, the Mw of the liquid diene polymer is the polystyrene equivalent determined by gel permeation chromatography (GPC).

[0157] As a liquid rubber, products from companies such as Kuraray Corporation and Clayville Corporation can be used.

[0158] (iii) Resin composition The tread rubber composition preferably contains a resin component. It is believed that by including a resin component, the loss tangent can be reduced, thus effectively suppressing heat generation on the tread surface during driving.

[0159] The resin component also functions as an adhesive agent and can be solid or liquid at room temperature. Specific resin components preferably include, for example, rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc., and two or more can be used in combination. Furthermore, these resin components can be endowed with modifying groups that can react with silica, etc., as needed. Moreover, the content relative to 100 parts by weight of the rubber component is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and even more preferably 30 parts by weight or more. As an upper limit, for example, it is preferably 60 parts by weight or less, more preferably 50 parts by weight or less.

[0160] Rosin-based resins are resins whose main component is rosin acid, obtained through the processing of rosin. These rosin-based resins (rosin derivatives) can be classified according to whether they are modified or not, into unmodified rosin and modified rosin derivatives. Examples of unmodified rosin include tall rosin (also known as tall oil rosin), resin rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosin. Modified rosin derivatives are modified forms of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosin derivatives, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0161] Styrene-based resins are polymers that use styrene-based monomers as constituent monomers. Examples include polymers polymerized with styrene-based monomers as the main component (50% by mass or more). Specifically, in addition to homopolymers formed by polymerizing styrene-based 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 formed by copolymerizing two or more styrene-based monomers, copolymers of styrene-based monomers and other monomers that can be copolymerized with these monomers can also be listed.

[0162] Examples of other monomers mentioned above include acrylonitrile, methacrylonitrile, and other acrylonitrile derivatives; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate; dienes such as chloroprene, butadiene, and isoprene; alkenes such as 1-butene and 1-pentene; and α,β-unsaturated carboxylic acids or their anhydrides such as anhydrous maleic acid.

[0163] Among coumarone-based resins, coumarone-indene resin is preferred. Coumarin-indene resin is a resin containing coumarone and indene as monomeric components constituting the resin backbone (main chain). Other monomeric components in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0164] The hydroxyl value (OH value) of coumarin indole resin is, for example, greater than 15 mg KOH / g and less than 150 mg KOH / g. Furthermore, the OH value refers to the amount of potassium hydroxide required, expressed in milligrams, to neutralize the acetic acid bonded to the hydroxyl group when 1 g of the resin is acetylated; this value is determined by potentiometric titration (JIS K 0070:1992).

[0165] The softening point of the coumarin indene resin is, for example, greater than 30°C and less than 160°C. Furthermore, the softening point is the temperature at which the ball drops when the softening point specified in JIS K 6220-1:2001 is determined using a ring-and-ball softening point measuring apparatus.

[0166] Examples of terpene-based resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds, as well as their hydrides. Terpene compounds are composed of (C5H8) resins. n The composition of hydrocarbons and their oxygen-containing derivatives is represented by the classifying hydrocarbons as monoterpenes (C14). 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 Compounds with terpenes as their basic skeleton include, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, allocirrhene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinene oil, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0167] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which use the aforementioned terpene compounds as raw materials, hydrogenated terpene resins that have undergone hydrogenation treatment of these terpene resins can also be listed. As terpene phenols, resins copolymerized from the aforementioned terpene compounds and phenolic compounds, as well as resins that have undergone hydrogenation treatment of these resins, can be listed. Specifically, resins obtained by condensing the aforementioned terpene compounds, phenolic compounds, and formalin can be listed. Furthermore, phenolic compounds, for example, phenol, bisphenol A, cresol, and xylenol can be listed. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, as well as resins that have undergone hydrogenation treatment of these resins, can be listed. Furthermore, as aromatic compounds, there are no particular limitations as long as the compound has an aromatic ring. Examples include phenols such as phenol, alkylphenol, alkoxyphenol, and phenols containing unsaturated hydrocarbon groups; naphthols such as naphthol, alkylnaphthol, alkoxynaphthol, and naphthols containing unsaturated hydrocarbon groups; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and styrene containing unsaturated hydrocarbon groups; coumarone, indene, etc.

[0168] "C5 resin" refers to a resin obtained by polymerizing C5 fractions. 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.

[0169] "C9 resin" refers to resins obtained by polymerizing C9 fractions, or their hydrogenated or modified products. Examples of C9 fractions include, for example, petroleum fractions with 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. Specifically, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resins are preferred. As aromatic vinyl resins, α-methylstyrene (AMS resin) or homopolymers of styrene or copolymers of α-methylstyrene and styrene are preferred for economic reasons, ease of processing, and excellent exothermic properties; copolymers of α-methylstyrene and styrene are more preferred. For example, commercially available substances from companies such as Kraton and Eastman Chemical Company can be used as aromatic vinyl resins.

[0170] "C5C9 resin" refers to a resin obtained by copolymerizing the aforementioned C5 fraction and the aforementioned C9 fraction, or it may be a hydrogenated or modified product of them. Examples of C5 and C9 fractions include the aforementioned petroleum fractions. For example, commercially available substances from Tosoh Corporation, LUHUA Corporation, etc., can be used as C5C9 resin.

[0171] There are no particular limitations on the acrylic resin used; for example, solvent-free acrylic resins can be used.

[0172] Solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized via high-temperature continuous polymerization (high-temperature continuous block polymerization) (as described in U.S. Patent No. 4,414,370, Japanese Patent Application Publication Nos. 59-6207, 5-58005, 1-313522, U.S. Patent No. 5,010,166, and the Toa Synthetic Research Yearbook TREND2000 No. 3, pp. 42-45). Furthermore, in this invention, (meth)acrylic acid refers to both methacrylic acid and acrylic acid.

[0173] Examples of monomeric components constituting the above-mentioned acrylic resins include (meth)acrylic acid, (meth)acrylates (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylamide derivatives.

[0174] In addition, as a monomer component constituting the above-mentioned acrylic resins, aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene can also be used together with (meth)acrylic acid and (meth)acrylic acid derivatives.

[0175] The aforementioned acrylic resins can be resins composed solely of (meth)acrylic acid, or resins with components other than (meth)acrylic acid as constituent elements. Furthermore, the aforementioned acrylic resins may also contain hydroxyl, carboxyl, or silanol groups, etc.

[0176] As a resin component, products from companies such as Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Co., Ltd., Rutgers Chemicals Co., Ltd., BASF Co., Ltd., Kraton Corporation, Nippon Paint Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd., etc. can be used.

[0177] (③) Wax The rubber composition for the driving surface may also contain wax. The wax content relative to 100 parts by weight of the rubber component is preferably 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, and even more preferably 1.5 parts by weight or more. As an upper limit, it is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less.

[0178] There are no particular limitations on the type of wax used; any type commonly used in the tire industry can be preferred. Examples include mineral-based waxes and plant-derived waxes. Mineral-based 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-based waxes are preferred.

[0179] Plant-derived waxes include, for example, rice bran wax, carnauba wax, and candelilla wax. Mineral-based waxes include, for example, paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. Furthermore, in this invention, the wax is designed to be free of stearic acid.

[0180] In addition, as waxes, commercially available substances such as those from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiwa Co., Ltd., and Paramelt Co., Ltd. can be used. These waxes can be used alone or in combination of two or more.

[0181] (④) Anti-aging agents The rubber composition for the driving surface may also contain antioxidants. The content of antioxidants is, for example, greater than 1 part by weight and less than 10 parts by weight relative to 100 parts by weight of the rubber component.

[0182] As an antioxidant, there are no particular limitations; examples include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octyl 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'-xylyl-p-phenylenediamine. Antioxidants include p-phenylenediamine-based antioxidants such as DTPD, N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrene-modified phenol; and bis, tri, and polyphenol-based antioxidants such as tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. Preferably, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are used, more preferably polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline. These can be used alone or in combination of two or more.

[0183] As commercially available products, for example, products from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., Flexis Co., Ltd., etc. can be used.

[0184] (⑤) Processing aids The rubber composition for the driving surface may also 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 can 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.

[0185] Metals used in metal salts include, for example, alkali metals such as potassium and sodium, or alkaline earth metals such as calcium and barium. Magnesium, zinc, nickel, and molybdenum can also be used. Alkali metals are preferred.

[0186] Acids used as metal salts include, for example, fatty acids such as lauric acid, myristic acid, and palmitic acid. Other acids that can be used include boric acid, carbonic acid, hydrochloric acid, nitric acid, and sulfuric acid.

[0187] Commercially available processing aids include products from companies such as Kishida Chemical Co., Ltd., Kenei Pharmaceutical Co., Ltd., STRUKTOL Co., Ltd., and Performance Additives Co., Ltd.

[0188] The content of processing aids relative to 100 parts by weight of rubber component is preferably 1 part by weight or more, more preferably 2 parts by weight or more. As an upper limit, for example, it is preferably 6 parts by weight or less, more preferably 4 parts by weight or less.

[0189] (⑥) Lubricant (stearic acid) The rubber composition for the driving surface may also contain a lubricant. As a lubricant, a fatty acid derivative-based lubricant such as stearic acid is preferably used. As stearic acid, conventionally known substances can be used; specifically, for example, products from Nippon Yu Co., Ltd., NOF Corporation, Kao Corporation, Fujifilm, Kojun Pharmaceutical Co., Ltd., and Chiba Fatty Acid Co., Ltd. can be used. Alternatively, STRUKTOL WB16 manufactured by STRUKTOL Co., Ltd. can also be used.

[0190] The content of stearic acid relative to 100 parts by weight of the rubber component is preferably greater than 0.5 parts by weight, more preferably 2.0 parts by weight or more. As an upper limit, it is preferably less than 10.0 parts by weight.

[0191] (⑦) Zinc oxide The rubber composition for the driving surface may also contain zinc oxide. The content of zinc oxide relative to 100 parts by weight of the rubber component is preferably greater than 0.5 parts by weight, more preferably 3.0 parts by weight or more. As an upper limit, it is preferably less than 10 parts by weight. As zinc oxide, conventionally known substances can be used, such as products from Mitsui Metal Mining Co., Ltd., Toho Co., Ltd., HAKUSUI TECH Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc.

[0192] (⑧) Crosslinking agents and vulcanization accelerators The rubber composition for the driving surface preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent relative to 100 parts by weight of the rubber component is preferably greater than 0.1 parts by weight, more preferably 2.0 parts by weight or more. As an upper limit, it is preferably less than 10.0 parts by weight. Furthermore, the sulfur content refers to the amount of pure sulfur; when insoluble sulfur is used, it does not include the content of oil.

[0193] As for sulfur, examples commonly used in the rubber industry include powdered sulfur, settled sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, and soluble sulfur. These can be used individually or in combination of two or more.

[0194] In addition, products made from companies such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Co., Ltd., Nippon Kanryu Kogyo Co., Ltd., and Hosoi Chemical Industry Co., Ltd. can be used as sulfur.

[0195] Crosslinking agents other than sulfur can also be used. Specifically, for example, sulfur-containing vulcanizing agents such as TACKIROL V200 manufactured by Taoka Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6-hexamethylene dithiosulfate dihydrate) manufactured by Flexis, KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyl dithio)hexane: mixed crosslinking agent) manufactured by Lanxess, and organic peroxides such as dicumyl peroxide can be used.

[0196] Furthermore, the rubber composition for the driving surface preferably contains a vulcanization accelerator. The content of the vulcanization accelerator relative to 100 parts by weight of the rubber component is preferably greater than 0.3 parts by weight, more preferably 4.0 parts by weight or more. As an upper limit, it is preferably less than 10.0 parts by weight.

[0197] Examples of vulcanization accelerators include thiazole-based accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-oxyvinyl-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based accelerators such as diphenylguanidine, di-o-toluidine, and o-toluidine biguanide. These can be used alone or in combination of two or more.

[0198] (⑨) Other In addition to the components mentioned above, the tire tread 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 relative to 100 parts by weight of the rubber component is, for example, greater than 0.1 parts by weight and less than 50 parts by weight.

[0199] Furthermore, in this invention, the various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the compound of this invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process of synthesizing methane from carbon dioxide can be converted.

[0200] (2) Preparation of rubber composition The driving surface rubber composition can be produced by a general method, for example, by a manufacturing method that includes a basic kneading process of mixing rubber components and fillers such as silica, and a final kneading process of mixing the mixture obtained in the basic kneading process with a crosslinking agent.

[0201] For example, well-known (closed) mixing machines such as Banbury internal mixers, kneaders, and open roll mills can be used for mixing.

[0202] The mixing temperature in the basic kneading process is, for example, greater than 50°C and less than 200°C, and the mixing time is, for example, greater than 30 seconds and less than 30 minutes. In addition to the above-mentioned components, in the basic kneading process, compounding agents used in the rubber industry in the past can be added as needed, such as softeners like oils, stearic acid, zinc oxide, antioxidants, waxes, vulcanization accelerators, etc., and then mixed.

[0203] In the final kneading process, the mixture obtained in the basic kneading process is kneaded with the crosslinking agent. The kneading temperature in the final kneading process is, for example, above room temperature and below 80°C, and the kneading time is, for example, above 1 minute and below 15 minutes. In addition to the above-mentioned components, vulcanization accelerators, zinc oxide, etc., may be added as needed during the final kneading process.

[0204] The aforementioned tread rubber composition can be extruded into a specified shape to form a tire tread.

[0205] 3. Tire manufacturing The tire described in this embodiment can be manufactured using conventional methods. First, the tread is manufactured by shaping the tread rubber composition obtained above into a predetermined shape. Then, it is assembled with other rubber components on a tire forming machine to produce an uncured tire.

[0206] Furthermore, when the tread is configured as a multi-layered structure consisting of a tread rubber layer and a base rubber layer, the rubber composition forming the base rubber layer (base rubber composition) can be obtained by essentially using the aforementioned rubber components and compounding materials, with appropriate variations in their proportions, and by similarly mixing. Then, after being extruded and formed into a tread rubber of a specified shape together with the tread rubber layer, an uncured tire can be manufactured by forming it together with other tire components on a tire forming machine using conventional methods.

[0207] Specifically, an uncured tire is manufactured by assembling an inner liner (for ensuring the tire's airtightness), a carcass (for withstanding loads, impacts, and air pressure on the tire), a belt assembly (for increasing the rigidity of the tread that strongly secures the carcass), and a bead assembly (for winding the belt and securing the tire to the rim at both ends of the carcass at the two side edges). After being shaped into a semi-circular ring, the tread is formed by adhering it to the center of the outer periphery, while the sidewall is adhering it to the radially outer side to form the sidewall.

[0208] Then, the uncured tires prepared above are heated and pressurized in a vulcanizing machine to obtain tires. The vulcanization process can be carried out using known vulcanization methods. For example, the vulcanization temperature is 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.

[0209] As mentioned earlier, the resulting tire, due to the proper control of (tanδ×La), is able to sufficiently suppress the heating of the tread during driving of tires using sustainable cords in the carcass ply cords.

[0210] Furthermore, the tires involved in this invention are not limited to a specific classification and can be used as tires for passenger cars, large passenger cars, large SUVs, trucks and buses, two-wheeled vehicles, racing tires, studless anti-skid tires (winter tires), all-season tires, run-flat tires, aircraft tires, mining tires, non-pneumatic tires, etc., but are preferably defined as tires for passenger cars. Moreover, pneumatic tires are preferred.

Example

[0211] The following examples (embodiments) are considered preferred in practice, but the scope of the invention is not limited to these embodiments.

[0212] The results of the study on heat suppression performance using tires (tire size: 225 / 55R16, section height-to-width ratio: 55%) consisting of various carcasses, treads and other rubber components as shown below are shown in the lower part of Tables 1 and 2.

[0213] 1. Manufacturing of the rubber composition for the driving surface Use the various compounding materials shown below to prepare a driving surface rubber composition.

[0214] (1) Compound materials (a) Rubber composition (①)NR: TSR20 (②) SBR: Modified S-SBR obtained by the method shown below (Manufacturing Example 1) (Styrene content: 25% by mass, Vinyl content: 25% by mass) (③)BR: Ube Industries manufactured UBEPOL BR150B (high-speed BR). (cis content 97% by mass, trans content 2% by mass, vinyl content 1% by mass)

[0215] (Manufacturing Example 1) The SBR described above was prepared according to the following steps. First, two high-pressure reactors with a 10L internal volume, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a casing were connected in series. Butadiene, styrene, and cyclohexane were mixed in their respective specified ratios. This mixture was passed through a dehydration column filled with activated alumina, and after being mixed with n-butyllithium in a static mixer to remove impurities, it was continuously supplied from the bottom of the first reactor. Further, 2,2-bis(2-tetrahydrofuranyl)propane as a polar agent and n-butyllithium as a polymerization initiator were continuously supplied from the bottom of the first reactor at a specified rate, maintaining the reactor temperature at 95°C. The polymer solution was continuously extracted from the top of the reactor and supplied to the second reactor. Maintaining the temperature of the second reactor at 95°C, a mixture of tetraglycidyl-1,3-diaminomethylcyclohexane (monomer) and oligomer components was continuously added as a 1000-fold dilution of cyclohexane at a specified rate to carry out the modification reaction. The polymer solution was continuously extracted from the reactor, and antioxidants were continuously added using a static mixer. The solvent was then removed to obtain the target modified diene polymer (SBR).

[0216] (b) Compounds other than rubber components (①) Carbon black: DIABLACK N220 manufactured by Mitsubishi Chemical Corporation (N2SA: 115m) 2 / g) (②) Silica: Ultrasil VN3 manufactured by Evonik Industries (N2SA: 175m) 2 / g, average primary particle size: 17nm) (③) Silane coupling agent: Si266 manufactured by Evonik Industries, Inc. (bis(3-triethoxysilylpropyl)disulfide) (④) Resin: SylvATRAXX 4401 manufactured by Kraton Corporation (α-Methylstyrene resin) (⑤) Oil: Diana Process NH-70S manufactured by Idemitsu Kosan Co., Ltd. (Aromatic processing oils) (⑥) Stearic acid: TSUBAKI stearic acid beads manufactured by Nippon Oil Company. (⑦) Zinc oxide: Zinc oxide No. 2 manufactured by Mitsui Metals & Mining Co., Ltd. (⑧) Sulfur: Powdered sulfur (containing 5% oil) manufactured by Tsurumi Chemical Industry Co., Ltd. (⑨) Vulcanization accelerator-1: NOCCELLER CZ manufactured by Ouchi Shinshin Chemical Industry Co., Ltd. (N-Cyclohexyl-2-benzothiazolylsulfonamide (CBS)) (⑩) Vulcanization accelerator-2: SOXINOL D (DPG) manufactured by Sumitomo Chemical Co., Ltd. (N,N'-diphenylguanidine)

[0217] (2) Manufacturing of tread rubber composition (driving tread rubber composition) Based on the formulations shown in Tables 1 and 2, materials other than sulfur and vulcanization accelerators were mixed at 150°C for 5 minutes using a Banbury internal mixer to obtain the compound. Furthermore, all formulation amounts are parts by weight.

[0218] Then, sulfur and vulcanization accelerator are added to the mixture, and it is kneaded for 5 minutes at 80°C using an open rolling mill to obtain the rubber composition for each driving surface.

[0219] 2. Manufacturing of the tread area Using the tread rubber compositions obtained above and the separately prepared base rubber composition, the tread area is manufactured by extrusion in a specified shape in such a way that the contact area ratio of the tread area is the value shown in Tables 1 and 2 (thickness of tread rubber layer / thickness of the entire tread area: 80%).

[0220] 3. Manufacturing of tire cord fabric In addition, except for using the specifications of each cord fabric shown in Tables 1 and 2, the tire cord fabric is manufactured in the same specification. Furthermore, in Tables 1 and 2, PET (bio) refers to cord fabric made using bio-polyester derived from biological raw materials, and PET (recycled) refers to cord fabric made using recycled polyester recycled from plastic waste such as PET bottles and old clothes.

[0221] Furthermore, in the specifications of each tire cord shown in Tables 1 and 2, the strength S, total fineness, intermediate elongation E, and breaking elongation are values ​​determined according to the methods specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords". Moreover, the cord diameter F is a value determined as the equivalent circle diameter of the circumcircle of the cross-section perpendicular to the extension direction, and the density D is a value determined as the number of cords present in a 5cm width perpendicular to the length direction. Additionally, the isophthalic acid content IF is a value determined by high-performance liquid chromatography (HPLC), and the damp heat resistance strength retention rate is a value obtained by calculating the ratio of the strength after treatment with saturated water vapor at 135°C for 48 hours (damp heat treatment) to the strength before treatment.

[0222] 4. Manufacturing of pneumatic tires Then, it is bonded together with other tire components to form an uncured tire with the ground contact area ratio shown in Tables 1 and 2. It is then pressurized and vulcanized at 170°C for 10 minutes to manufacture the test tires of Examples 1 to 6 and Comparative Examples 1 to 3.

[0223] Then, rubber test pieces with a length of 20mm × width of 4mm × thickness of 1mm were cut from the tread rubber layer of each test tire with the tire circumference as the long side to make a viscoelasticity test piece. For each rubber test piece, the loss tangent tanδ was measured using the "EPLEXOR (registered trademark)" series manufactured by GABO under the conditions of temperature 30℃, frequency 10Hz, initial strain 5%, and dynamic strain 1%, using the deformation mode: tension.

[0224] Furthermore, the thickness direction of the sample was set to the radial direction of the tire. Additionally, when the same formulation was used in multiple embodiments, it was set to the average value measured from each test tire.

[0225] 5. Parameters Then calculate (tanδ×La), (tanδ×La) / F and ((tanδ×La) / F) / (100-IF).

[0226] 6. Performance Evaluation (Evaluation of Heat Suppression Performance) All test tires were installed on all wheels of a Japanese-made FR car (2000cc engine), and inflated to a pressure of 250 kPa (standard internal pressure for passenger cars). The vehicle was driven on a test route on a dry asphalt surface at an average speed of approximately 100 km / h. Immediately after driving, the temperature of each test tire was measured 5 mm from the center of the tread surface, starting from the center and moving radially inwards. The difference between this temperature and the ambient temperature was calculated.

[0227] Then, the result from Comparative Example 1 is taken as 100 and exponentialized based on the following formula to evaluate the heat suppression performance. The larger the value, the less heat is generated and the better the heat suppression performance. Heat suppression performance = [(Result of Comparative Example 1) / (Result of the test tire)] × 100

[0228] Table 1

[0229] Table 2

[0230] The present invention has been described above based on embodiments, but the present invention is not limited to the embodiments described above. Various modifications can be made to the embodiments described above within the same and equivalent scope as the present invention.

[0231] The present invention (1) is a tire, characterized in that, It is a tire with a tread layer containing a tread rubber layer and a carcass. Sustainable polyester cords are used as cords in the tire carcass fabric that constitutes the tire carcass portion. The product of the loss tangent tanδ, measured under the conditions of 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode of tension, and the ground contact area ratio La (%) calculated from the ground contact area of ​​the tread, (tanδ×La), satisfies the following formula: tanδ×La≦15.

[0232] The present invention (2) is a tire according to the present invention (1), characterized in that, The value of (tanδ×La) is less than 13.

[0233] The present invention (3) is a tire according to the present invention (1) or (2), characterized in that, The ratio of (tanδ×La) to the diameter F (mm) of the sustainable cord ((tanδ×La) / F) is less than 24.

[0234] The present invention (4) is a tire according to the present invention (3), characterized in that, The ((tanδ×La) / F) is less than 21.

[0235] The present invention (5) is a tire according to any combination of any one of (1) to (4) of the present invention, characterized in that, The sustainable polyester cord is a sustainable polyethylene terephthalate cord.

[0236] The present invention (6) is a tire according to any combination of any one of (1) to (5) of the present invention, characterized in that, The isophthalic acid content in the sustainable polyester cord is less than 0.1 mol%.

[0237] The present invention (7) is a tire according to any combination of any one of (1) to (6) of the present invention, characterized in that, The strength S (cN / dtex) of the sustainable polyester cord is above 6.0 cN / dtex.

[0238] The present invention (8) is a tire according to any combination of any one of (1) to (7) of the present invention, characterized in that, The relationship between (La×tanδ) and the content of isophthalic acid IF (mol%) in the sustainable polyester cord ((tanδ×La) / F) / (100-IF) is less than 0.21.

[0239] The present invention (9) is a tire according to any combination of any one of (1) to (8) of the present invention, characterized in that, The relationship between the strength S (cN / dtex) of the sustainable polyester cord and the isophthalic acid content IF (mol%) and the loss tangent tanδ of the running surface rubber layer (S×IF / tanδ) is greater than 50.

[0240] The present invention (10) is a tire according to any combination of any one of (1) to (9) of the present invention, characterized in that, The product (S×D) of the strength S (cN / dtex) of the sustainable polyester cord and the number D (cords / 5cm) of the sustainable polyester cord present in a width of 5cm perpendicular to the length direction of the sustainable polyester cord in the tread portion is 160 or more.

[0241] The present invention (11) is a tire according to the present invention (10), characterized in that, The (S×D) is 190 or higher.

[0242] The present invention (12) is a tire according to any combination of any one of (1) to (11) of the present invention, characterized in that, The relationship (L×D / E) between the intermediate elongation E (%) of the sustainable polyester cord under a specified load L (cN / dtex) and the number D (cords / 5cm) of the sustainable polyester cord present in a width of 5cm perpendicular to the length direction of the sustainable polyester cord in the tread portion is 12 or more and 20 or less.

[0243] The present invention (13) is a tire according to the present invention (12), characterized in that, The (L×D / E) is 14 or higher and 15 or lower.

[0244] The present invention (14) is a tire according to any combination of any one of (1) to (13) of the present invention, characterized in that the elongation at break of the sustainable polyester cord is 10% or more.

[0245] The present invention (15) is a tire according to any combination of any one of (1) to (14) of the present invention, characterized in that the moisture and heat resistance strength retention rate of the sustainable polyester cord is 80% or more.

Claims

1. A tire, characterized in that, It is a tire with a tread layer containing a tread rubber layer and a carcass. Sustainable polyester cords are used as cords in the tire carcass fabric that constitutes the tire carcass portion. The product of the loss tangent tanδ, measured under the conditions of 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode of tension, and the ground contact area ratio La calculated from the ground contact area of ​​the tread, tanδ×La, satisfies the following formula: tanδ×La≦15, The grounding area ratio La is expressed in percentages.

2. The tire according to claim 1, characterized in that, The tanδ×La is less than 13.

3. The tire according to claim 1 or 2, characterized in that, The ratio of tanδ×La to the diameter F of the sustainable cord (tanδ×La) / F is less than 24. The diameter F is measured in mm.

4. The tire according to claim 3, characterized in that, The (tanδ×La) / F is less than 21.

5. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord is a sustainable polyethylene terephthalate cord.

6. The tire according to claim 1 or 2, characterized in that, The isophthalic acid content in the sustainable polyester cord is less than 0.1 mol%.

7. The tire according to claim 1 or 2, characterized in that, The strength S of the sustainable polyester cord is above 6.0 cN / dtex. The unit of the intensity S is cN / dtex.

8. The tire according to claim 1 or 2, characterized in that, The relationship between La×tanδ and the isophthalic acid content IF in the sustainable polyester cord ((tanδ×La) / F) / (100-IF) is less than 0.

21. The content of isophthalic acid (IF) is expressed in moles.

9. The tire according to claim 1 or 2, characterized in that, The relationship between the strength S of the sustainable polyester cord, the isophthalic acid content IF, and the loss tangent tanδ of the rubber layer on the driving surface, S×IF / tanδ, is greater than 50. The intensity S is measured in cN / dtex, and the content IF is measured in moles.

10. The tire according to claim 1 or 2, characterized in that, The product of the strength S of the sustainable polyester cord and the number D of the sustainable polyester cords present in a width of 5 cm perpendicular to the length direction of the sustainable polyester cords in the tread portion, S×D, is greater than 160. The unit of the strength S is cN / dtex, and the unit of the number of roots D is roots / 5cm.

11. The tire according to claim 10, characterized in that, The S×D is 190 or higher.

12. The tire according to claim 1 or 2, characterized in that, The relationship between the intermediate elongation E of the sustainable polyester cord under a specified load L and the number of cords D in a width of 5 cm perpendicular to the length direction of the sustainable polyester cord in the tread portion is L×D / E, which is more than 12 and less than 20. The unit of the specified load L is cN / dtex, the unit of the intermediate elongation E is %, and the unit of the number of cords D is cords / 5cm.

13. The tire according to claim 12, characterized in that, The L×D / E ratio is between 14 and 15.

14. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord has a breaking elongation of more than 10%.

15. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord retains more than 80% of its strength in terms of resistance to damp heat.

16. The tire according to claim 1, characterized in that, The value of tanδ×La is greater than or equal to 1.

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