Tire

Abstract

The invention provides a tire which realizes improvement of comprehensive performance of low fuel consumption and durability. A tire provided with a belt layer formed by coating a belt layer cord with a rubber composition, the belt layer cord comprising four filaments, the rubber composition having a cobalt content of less than 0.15 parts by mass with respect to 100 parts by mass of a rubber component, and a carbon content of less than 0.15 parts by mass with respect to 100 parts by mass of the rubber component. The diameter D (mm) of the belt cord, the complex elastic modulus E * (MPa) measured under the conditions of the rubber composition at a temperature of 70 DEG C, an initial strain of 5%, a dynamic strain of + / -1%, a frequency of 10 Hz, and a deformation mode of stretching, and the cobalt amount C (parts by mass) per 100 parts by mass of the rubber component in the rubber composition satisfy the following formulae. D / E * lt; 0.1 * C+0.170

Description

Technical Field

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

[0002] Patent Document 1 describes a pneumatic tire having a carcass, a belt layer, and a chafer layer.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-239069 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An object of the present invention is to improve the comprehensive performance of low fuel consumption and durability.

[0008] Means for Solving the Problems

[0009] The present invention relates to a tire having a belt layer formed by covering a belt layer cord with a rubber composition, and the tire is characterized in that

[0010] the above-mentioned belt layer cord is composed of 4 filaments,

[0011] in the above-mentioned rubber composition, the amount of cobalt is less than 0.15 parts by mass relative to 100 parts by mass of the rubber component,

[0012] the diameter D (mm) of the above-mentioned belt layer cord, the complex elastic modulus E * (MPa) measured under the conditions of a temperature of 70°C, an initial strain of 5%, a dynamic strain of ±1%, a frequency of 10 Hz, and a deformation mode of tension, and the amount of cobalt C (parts by mass) relative to 100 parts by mass of the rubber component in the above-mentioned rubber composition satisfy the following formula.

[0013] D / E * <0.1 × C + 0.170

[0014] Advantages of the Invention

[0015] According to the present invention, it is possible to improve the comprehensive performance of low fuel consumption and durability. Brief Description of the Drawings

[0016] Figure 1 is a schematic cross-sectional view showing the structure of a tire according to an embodiment of the present invention.

[0017] Figure 2 is a schematic view for explaining the measurement of bending rigidity. Detailed Description

[0018] [1] Features of the tire of the present invention

[0019] First, the features of the tire of the present invention will be described.

[0020] 1. Outline

[0021] The tire of the present invention is a tire having a belt layer formed by covering a belt layer cord (hereinafter also simply referred to as "cord") with a rubber composition. And the belt layer cord is composed of 4 filaments. In the rubber composition, the cobalt amount is less than 0.15 parts by mass relative to 100 parts by mass of the rubber component. In addition, the diameter D (mm) of the belt layer cord, the complex elastic modulus E * (MPa) measured under the conditions of temperature: 70 °C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tension, and the cobalt amount C (parts by mass) relative to 100 parts by mass of the rubber component in the rubber composition satisfy the following formula.

[0022] D / E * <0.1 × C + 0.170

[0023] By having these features, as described later, it is possible to improve the comprehensive performance of low fuel consumption and durability.

[0024] It should be noted that the above complex elastic modulus E * For example, it can be measured using a viscoelasticity measuring device such as "EPLEXOR (registered trademark)" manufactured by GABO.

[0025] 2. Mechanism of effect manifestation in the tire of the present invention

[0026] Regarding the mechanism of the above effect manifestation in the tire of the present invention, the following can be considered.

[0027] In the past, in the rubber composition of the belt layer cord fabric layer constituting the belt layer, cobalt was contained as an impurity in order to improve the adhesion to the belt layer cord. However, in recent years, from the aspect of SDGs, cobalt-free is strongly required.

[0028] However, if the cobalt content in the rubber composition is reduced, the adhesion between the cord and the rubber decreases, and BEL (BELT EDGE LOOSENESS, belt layer edge looseness) or looseness such as cord-rubber peeling occurs at the end, which may deteriorate the durability of the tire.

[0029] Therefore, as a countermeasure against durability deterioration, increasing the thickness (gauge) of the belt layer (belt layer cord fabric layer) is considered. However, if the thickness is increased, it may lead to a decrease in low fuel consumption.

[0030] In the present invention, the belt layer cord is composed of 4 filaments. By forming the belt layer cord from 4 filaments, the cord diameter can be reduced, so that even without increasing the thickness, sufficient rubber thickness (thickness on the cord) can be ensured, and the occurrence of BEL or looseness can be suppressed.

[0031] Moreover, the belt layer cord with a small cord diameter can reduce the contact area with the rubber. Therefore, even if the cobalt content in the rubber composition is reduced to less than 0.15 parts by mass relative to 100 parts by mass of the rubber component, sufficient adhesion between the cord and the rubber can be ensured. In addition, the reduction of the cobalt content can reduce the loss tangent (tanδ) and achieve an improvement in low fuel consumption performance.

[0032] Here, the filaments constituting the belt layer cord preferably have a circular cross-sectional shape, but may also be elliptical. And, corrugation treatment can be performed, and plating treatment can also be performed. In addition, it can be untwisted, can be single-twist (1×4), or can be layer-twist (2+2), and a 1×4 structure is preferred. It should be noted that in the following embodiments, filaments with a circular cross-sectional shape are used without corrugation treatment in a single-twist (1×4 structure). As the belt layer cord, a metal cord is preferred, an iron cord is more preferred, and a steel cord is particularly preferred.

[0033] Moreover, in the above text, regarding the "cord diameter" of the belt layer cord, it refers to the diameter when the circumscribed circle of the cross-section perpendicular to the cord extension direction is a perfect circle, and in the case of an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the perfect circle assuming the same cross-sectional area).

[0034] In addition, in the present invention, the diameter D (mm) of the belt layer cord, the complex elastic modulus E * (MPa) measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tension for the rubber composition, and the cobalt amount C (parts by mass) relative to 100 parts by mass of the rubber component in the rubber composition satisfy the following formula.

[0035] D / E * <0.1×C + 0.170

[0036] The above formula indicates that in the present invention, the complex elastic modulus E of the rubber composition * is large enough relative to the cord diameter. Thus, by increasing the complex elastic modulus E of the rubber composition * , the movement of the cord ends can be sufficiently suppressed, so that the occurrence of BEL or looseness can be suppressed.

[0037] It should be noted that the belt layer is not limited to 1 layer and can also be 2 layers or more. In this case, regarding the above D / E *<0.1×C + 0.170, as long as at least one belt layer satisfies it, and it is more preferable that all belt layers satisfy it.

[0038] In the present invention, by appropriately controlling the composition or diameter of the belt layer cords and the cobalt amount in the rubber composition, and satisfying D / E * <0.1×C + 0.170, the above effects synergistically multiply, so it is considered that an improvement in the comprehensive performance of low fuel consumption and durability can be achieved.

[0039] It should be noted that the cobalt amount in the rubber composition is more preferably less than 0.10 parts by mass, further preferably less than 0.05 parts by mass, further preferably less than 0.05 parts by mass, further preferably less than 0.01 parts by mass, and further preferably less than 0.005 parts by mass with respect to 100 parts by mass of the rubber component. In addition, the lower limit is not particularly limited and can be 0 parts by mass (non-containing), and in this case, the above-mentioned cobalt-free can be achieved.

[0040] [2] More preferable mode in the tire of the present invention

[0041] The tire of the present invention can obtain greater effects by adopting the following methods.

[0042] 1. Density and surface area of the cords

[0043] In the present invention, the product (E × S) of the density of the cords (number of cords per 50 mm width in the tire width direction) E (pieces) and the surface area S (mm 2 / mm) per unit length (1 mm) in the belt layer (belt layer cord fabric layer) is preferably more than 60 (E × S > 60). By increasing (E × S) to more than 60, in the belt layer (belt layer cord fabric layer), the portion constrained by the rubber becomes larger, so the adhesion between the rubber and the cords can be more fully exerted. In addition, the movement of the cords can be sufficiently suppressed, so it is considered that the generation of BEL or loosening can be further suppressed, and the durability can be further improved.

[0044] 2. Density and flexural rigidity of the cords

[0045] In the present invention, the product (E × B) of the density of the cords and the flexural rigidity B (g·cm) in the belt layer (belt layer cord fabric layer) is preferably more than 1600 (E × B > 1600). By increasing (E × B) to more than 1600, the movement of the cords can be sufficiently suppressed, so it is considered that the generation of BEL or loosening can be further suppressed, and the durability can be further improved.

[0046] It should be noted that (E × B) is more preferably more than 2000, further preferably more than 2400, and further preferably more than 10000. The upper limit is not particularly limited, and for example, it is preferably less than 15000.

[0047] The flexural rigidity of the belt cord described above can be measured, for example, using a rigidity testing machine (e.g., model 150-D) manufactured by TABER Company (USA) according to the following steps. First, both ends of a 145-mm-long belt cord are attached to the chucks of the rigidity testing machine, as Figure 2 shown, and the belt cord 10 is given bending angles of +15 degrees and -15 degrees. Further, the average value of the bending moment at +15 degrees and the bending moment at -15 degrees is defined as the flexural rigidity value (g·cm).

[0048] 3. Carbon black contained in the rubber composition

[0049] In the present invention, in the rubber composition, it is preferable to contain 5 parts by mass or more and 70 parts by mass or less of carbon black having a BET specific surface area of 45 m 2 / g or more per 100 parts by mass of the rubber component.

[0050] Thereby, the complex elastic modulus E of the rubber composition can be further increased * , and thus it is considered that the generation of BEL or looseness or the like can be further suppressed, and a further improvement in durability can be achieved.

[0051] It should be noted that the content of carbon black is more preferably 30 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the rubber component.

[0052] The above BET specific surface area is the value of the nitrogen adsorption specific surface area (N2SA) measured by the BET method in accordance with ASTM D3037-93.

[0053] [3] Embodiment

[0054] Hereinafter, the present invention will be specifically described based on the embodiment.

[0055] 1. Tire of the present embodiment

[0056] Figure 1 is a schematic cross-sectional view showing the structure of the tire of the present embodiment, showing a tire meridian cross-section including the rotation axis in the normal state of the tire.

[0057] Here, the "normal state" means a state in which the tire is mounted on a normal rim, filled with a normal internal pressure, and has no load.

[0058] It should be noted that a "regular rim" refers to the rim specified for each tire in a standard system that includes the standard on which the tire is based. For example, in the case of JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim in the applicable sizes recorded in the "JATMA YEARBOOK"; in the case of ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" recorded in the "STANDARDS MANUAL"; in the case of TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" recorded in the "YEAR BOOK". Refer to them in the order of JATMA, ETRTO, and TRA. When there are applicable sizes during the reference, follow that standard. Additionally, in the case of a tire not specified in the standard, it refers to the rim that can assemble the tire and maintain the internal pressure, that is, the rim with the smallest rim diameter and then the narrowest rim width among the rims that do not leak air between the rim / tire.

[0059] Moreover, "regular internal pressure" refers to the air pressure specified for each tire in a standard system that includes the standard on which the tire is based. In the case of JATMA, it refers to the "maximum air pressure"; in the case of ETRTO, it refers to the "INFLATION PRESSURE"; in the case of TRA, it refers to the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". Refer to them in the order of JATMA, ETRTO, and TRA. When there are applicable sizes during the reference, follow that standard. In the case of a tire not specified in the standard, it refers to the regular internal pressure of other tire sizes (specified in the standard) for which the above regular rim is recorded as the standard rim (provided it is 250 KPa or more). It should be noted that in the case where there are multiple regular internal pressures of 250 KPa or more, it refers to the minimum value among them.

[0060] As Figure 1 shown, the tire 1 includes: a carcass 6 extending from a tread portion 2 through a sidewall portion 3 to a bead core 5 of a bead portion 4; and a belt layer 7 disposed radially outside the carcass 6 and inside the tread portion 2. It should be noted that C is the center line.

[0061] The carcass 6 is composed of at least one ply ( Figure 1 one ply in Figure 1In this case, 6a is the inner main body portion of the carcass ply 6A, and 6b is the outer folded-back portion. A bead filler 8, for example, extending radially outward of the tire from the bead core 5 is disposed between the inner main body portion 6a and the outer folded-back portion 6b.

[0062] The belt layer 7 is formed by arranging at least one ply of belt ply cords coated with cover rubber. The arrangement is formed by stranding steel cord having a 1×4 construction composed of 4 filaments at a specified density. Figure 1 In this case, the belt layer 7 is composed of two belt ply cords, i.e., a first belt ply cord 7A located radially inside the tire and a second belt ply cord 7B located outside the first belt ply cord 7A. Note that three or more belt ply cords may be used.

[0063] By adopting such a belt layer 7, as described above, it is possible to improve the comprehensive performance of low fuel consumption and durability.

[0064] 2. Rubber composition constituting the belt layer

[0065] In the present embodiment, the rubber composition constituting the belt layer can be obtained from the rubber components and other compounding materials described below.

[0066] (1) Compounding materials

[0067] (a) Rubber components

[0068] In the present embodiment, the rubber components are not particularly limited, and diene rubbers such as isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), and butyl rubbers such as butyl rubber, which are commonly used in tire manufacturing, can be used. Among these, isoprene rubber is preferred, and NR is preferably used in view of the cis structure of polyisoprene being close to 100% and the tensile strength being superior to other rubber components. Note that BR and SBR may be used simultaneously as needed.

[0069] (①) Isoprene rubber

[0070] The content (total content) of isoprene rubber in 100 parts by mass of the rubber components is preferably 80 parts by mass or more, more preferably 90 parts by mass or more.

[0071] Examples of isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. NR is preferably used in view of its excellent strength.

[0072] As NR, for example, SIR20 can be used. NRs commonly used in the tire industry such as TSR20. As IR, there is no particular limitation, and for example, IR2200 and other IRs commonly used in the tire industry can be used. As modified NRs, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. can be cited. As modified NRs, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be cited. As modified IRs, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be cited. They can be used alone or in combination of two or more.

[0073] (②) Other rubber components

[0074] In addition, as other rubber components, rubber (polymers) commonly used in the manufacture of tires such as butadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), etc. can be included as needed. It should be noted that as the content (total content) of these rubber components in 100 parts by mass of the rubber components, it is preferably 20 parts by mass or less, more preferably 10 parts by mass or less.

[0075] (b) Compounding materials other than rubber components

[0076] (①) Filler

[0077] In this embodiment, the rubber composition preferably contains a filler. As specific fillers, for example, carbon black, silica, graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. can be cited. Among them, carbon black can be preferably used as a reinforcing agent.

[0078] (i) Carbon black

[0079] There is no particular limitation on the carbon black, and furnace carbon blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF can be cited; acetylene carbon black; thermal carbon blacks such as FT and MT; channel carbon blacks such as EPC, MPC, and CC, etc. They can be used alone or in combination of two or more.

[0080] As described above, the BET specific surface area of the carbon black is preferably 45 m 2 / g or more. In addition, the content of the carbon black is preferably 5 parts by mass or more and 70 parts by mass or less, more preferably 30 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the rubber components.

[0081] The specific carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, products of, for example, Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, LION Corporation, Shin Nippon Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. They can be used alone or in combination of two or more.

[0082] (ii) Other fillers

[0083] In the rubber composition, in addition to the above carbon black, fillers such as silica, graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc., which are usually used in the tire industry, can be further contained as needed. Their content is, for example, more than 0.1 part by mass and less than 200 parts by mass relative to 100 parts by mass of the rubber component. It should be noted that when using silica, it is preferably used in combination with a silane coupling agent.

[0084] (②) Curing resin component

[0085] The rubber composition preferably contains a phenolic resin and / or a melamine resin as the curing resin component. Thereby, the heat generation property and the elongation at break are not significantly deteriorated, the adhesion to the steel cord can be improved, and it is easy to utilize a large reaction force generated by the rubber and the steel cord.

[0086] As specific phenolic resins, for example, PR12686 (cashew nut oil-modified phenolic resin) manufactured by Sumitomo Bakelite Co., Ltd. can be cited, and as melamine resins, for example, SUMIKANOL 507AP (modified etherified hydroxymethyl melamine resin) manufactured by Taoka Chemical Industry Co., Ltd. can be cited.

[0087] Regarding the content of the curing resin component, relative to 100 parts by mass of the rubber component, for example, from the aspect of sufficiently improving the complex elastic modulus and obtaining a large reaction force during deformation, it is preferably 1 part by mass or more, more preferably 2 parts by mass or more. On the other hand, from the aspect of maintaining the breaking strength, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 5 parts by mass or less.

[0088] Note that when using melamine resin, it is preferable to contain a methylene donor as a curing agent at the same time. Examples of the methylene donor include hexamethylenetetramine (HMT), hexamethoxymethylmelamine (HMMM), hexahydroxymethylmelamine pentamethyl ether (HMMPME), etc. Preferably, it contains, for example, 5 to 15 parts by mass relative to 100 parts by mass of the curable resin component. If the amount is too small, it may not be possible to obtain a sufficient complex elastic modulus. On the other hand, if it is too large, the viscosity of the rubber increases and the processability may deteriorate.

[0089] As a specific methylene donor, for example, SUMIKANOL 507 manufactured by Taoka Chemical Industry Co., Ltd. can be used.

[0090] (③) Plasticizer component

[0091] The rubber composition may contain oil (including extender oil), liquid rubber, and resin as components (plasticizers) for softening the rubber. Note that the plasticizer component is a component that can be extracted from vulcanized rubber by acetone. The total content of the plasticizer component is preferably more than 1 part by mass, more preferably 2 parts by mass or more relative to 100 parts by mass of the rubber component. On the other hand, it is preferably less than 20 parts by mass, more preferably less than 10 parts by mass. Note that the content of the oil also includes the amount of oil contained in the rubber (oil-extended rubber).

[0092] (i) Oil

[0093] Examples of the oil include processing oil, vegetable oil, animal oil, or a mixture thereof. As the processing oil, for example, paraffinic processing oil, aromatic processing oil, naphthenic processing oil, etc. can be used. Specific examples of the processing oil include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. Note that they can be used alone or in combination of two or more.

[0094] As a specific processing oil, for example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd., etc. can be used.

[0095] Examples of vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, fragrant oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc. They can be used alone or in combination of two or more.

[0096] As specific vegetable oils, commercially available vegetable oils such as those produced by Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY Corporation, H&R Corporation, Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0097] (ii) Liquid rubber

[0098] The liquid rubber cited as a plasticizer refers to a polymer in a liquid state at room temperature (25°C), and is a rubber component that can be extracted from vulcanized tires by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and their hydrides.

[0099] Farnesene-based polymers refer to polymers obtained by polymerizing farnesene and having a structural unit based on farnesene. Isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene) exist in farnesene.

[0100] The farnesene-based polymer can be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0101] Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), etc.

[0102] The weight-average molecular weight (Mw) in terms of polystyrene of the liquid diene-based polymer measured by gel permeation chromatography (GPC) is, for example, more than 1.0×10 3 and less than 2.0×10 5 . It should be noted that in this specification, the Mw of the liquid diene-based polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC).

[0103] As a specific liquid rubber, products of, for example, Kuraray Co., Ltd. and Cray Valley can be used.

[0104] (iii) Resin component

[0105] The resin component also functions as an adhesion - imparting component and can be solid or liquid at room temperature. As specific resin components, for example, rosin - based resins, styrene - based resins, benzofuran - based resins, terpene - based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. can be cited, and two or more of them can be used in combination.

[0106] Rosin - based resins are resins mainly composed of rosin acid obtained by processing pine resin. These rosin - based resins (rosins) can be classified according to whether they are modified or not, and can be classified into unmodified rosin (unmodified rosin) and rosin modifiers (rosin derivatives). As unmodified rosin, tall oil rosin (also known as tall oil pitch), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins can be cited. Rosin modifiers are modifiers of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid - modified rosins, unsaturated carboxylic acid - modified rosin esters, amide compounds of rosin, and amine salts of rosin.

[0107] Styrene - based resins are polymers using styrene - based monomers as constituent monomers, and examples include polymers obtained by polymerizing styrene - based monomers as the main component (50% by mass or more). Specifically, in addition to homopolymers obtained by homopolymerizing each styrene - based monomer (styrene, o - methylstyrene, m - methylstyrene, p - methylstyrene, α - methylstyrene, p - methoxystyrene, p - tert - butylstyrene, p - phenylstyrene, o - chlorostyrene, m - chlorostyrene, p - chlorostyrene, etc.) and copolymers obtained by copolymerizing two or more styrene - based monomers, copolymers of styrene - based monomers and other monomers copolymerizable with them can also be cited.

[0108] As the above - mentioned other monomers, acrylonitriles such as acrylonitrile and methacrylonitrile, 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, olefins such as 1 - butene and 1 - pentene; α,β - unsaturated carboxylic acids or their acid anhydrides such as maleic anhydride; etc. can be exemplified.

[0109] Among benzofuran - based resins, benzofuran - indene resins are preferred. Benzofuran - indene resins are resins containing benzofuran and indene as monomer components constituting the resin backbone (main chain). As monomer components contained in the backbone other than benzofuran and indene, styrene, α - methylstyrene, methyl indene, vinyltoluene, etc. can be cited.

[0110] The content of the coumarone indene resin is, for example, more than 1.0 part by mass and less than 50.0 parts by mass relative to 100 parts by mass of the rubber component.

[0111] The hydroxyl value (OH value) of the coumarone indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value refers to the amount of potassium hydroxide required to neutralize acetic acid bonded to the hydroxyl group when 1 g of the resin is acetylated, expressed in milligrams, and is a value measured by potentiometric titration (JIS K 0070: 1992).

[0112] The softening point of the coumarone indene resin is, for example, higher than 30° C. and lower than 160° C. The softening point is a softening point specified in JIS K 6220-1:2001 and measured using a ring and ball softening point measuring apparatus, and is a temperature at which a ball falls.

[0113] Examples of terpene resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are composed of (C5H8) n The hydrocarbons and their oxygenated derivatives are classified as monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ) and the like as a basic skeleton, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc. can be mentioned.

[0114] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. which are made from the above-mentioned terpene compounds as raw materials, hydrogenated terpene resins obtained by hydrogenating the terpene resins can also be cited. As terpene phenols, resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating such resins can be cited. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formaldehyde can be cited. It should be noted that as phenolic compounds, for example, phenol, bisphenol A, cresol, xylenol, etc. can be cited. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating such resins can be cited. It should be noted that as aromatic compounds, as long as they are compounds having an aromatic ring, there is no particular limitation, and for example, phenolic compounds such as phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group, etc.; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group, etc.; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, styrene containing an unsaturated hydrocarbon group, etc.; benzofuran, indene, etc. can be cited.

[0115] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. As the C5 fraction, for example, petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. can be cited. As C5 petroleum resins, dicyclopentadiene resin (DCPD resin) is preferably used.

[0116] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, or a resin obtained by hydrogenating or modifying them. As the C9 fraction, for example, petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, methylindene, etc. can be cited. As a specific example, for example, benzofuran indene resin, benzofuran resin, indene resin and aromatic vinyl resins are preferably used. As aromatic vinyl resins, due to reasons such as economy, easy processing, and excellent heat generation properties, homopolymers of α-methylstyrene or styrene, or copolymers of α-methylstyrene and styrene are preferred, and copolymers of α-methylstyrene and styrene are more preferred. As aromatic vinyl resins, for example, aromatic vinyl resins commercially available from companies such as KRATON and Eastman Chemical can be used.

[0117] "C5C9 resin" refers to a resin obtained by copolymerizing the above-mentioned C5 fraction and the above-mentioned C9 fraction, or a resin obtained by hydrogenating or modifying them. As the C5 fraction and the C9 fraction, the above-mentioned petroleum fractions can be cited. As C5C9 resins, for example, resins commercially available from Tosoh Corporation, LUHUA Company, etc. can be used.

[0118] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0119] Solvent-free acrylic resins include (meth) acrylic resins (polymers) synthesized by a high temperature continuous polymerization method (high temperature continuous bulk polymerization method) (methods described in U.S. Patent No. 4,414,370, Japanese Patent Publication No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Publication No. 1-313522, U.S. Patent No. 5,010,166, East Asia Synthesis Research Annual Report TREND 2000 No. 3, p. 42-45, etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as secondary raw materials as much as possible. It should be noted that in the present invention, (meth) acrylic acid refers to methacrylic acid and acrylic acid.

[0120] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, arylalkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0121] As monomer components constituting the acrylic resin, aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or a (meth)acrylic acid derivative.

[0122] The acrylic resin may be a resin composed only of a (meth)acrylic acid component or a resin containing components other than the (meth)acrylic acid component as constituent elements. In addition, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0123] Specific examples of the resin component include products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF Corporation, Arizona Chemical Co., Ltd., Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd.

[0124] (④) Cobalt

[0125] In the present invention, as described above, the rubber composition contains cobalt, which can improve the adhesion between the cord and the rubber.

[0126] As the cobalt-containing compound, cobalt organic acid can be cited, for example. As the specific cobalt organic acid, cobalt stearate, cobalt naphthenate, cobalt neodecanoate, cobalt neodecanoate borate, cobalt abietate, etc. can be cited. As a commercially available product, a product of Dainippon Ink and Chemicals, Incorporated, etc. can be used. They can be used alone by one kind, or two or more kinds can be used in combination. Among them, cobalt stearate is preferred.

[0127] It should be noted that, as the chemical other than the above cobalt organic acid, a substance in which the cobalt element is appropriately replaced with an element having an ionization tendency between zinc and copper can be used. As such a metal element, iron, nickel, tin, antimony, bismuth, etc. can be cited.

[0128] In the present invention, these cobalt-containing compounds are appropriately selected and compounded in such a manner that the cobalt amount is less than 0.15 parts by mass with respect to 100 parts by mass of the rubber component. It should be noted that, as described above, the cobalt amount is more preferably less than 0.10 parts by mass, further preferably less than 0.05 parts by mass, further preferably less than 0.05 parts by mass, further preferably less than 0.01 parts by mass, further preferably less than 0.005 parts by mass.

[0129] It should be noted that, as needed, an aliphatic (thiosulfate) sodium salt derivative such as sodium hexamethylene-1,6-bis(thiosulfate) dihydrate may also be contained together with the cobalt organic acid.

[0130] Since the aliphatic (thiosulfate) sodium salt derivative contains a sulfur atom, it also functions as a crosslinking agent, can balance the initial adhesiveness / heat-resistant adhesiveness / water-resistant adhesiveness of the rubber composition and the steel monofilament cord, and can improve the adhesiveness to the steel monofilament cord.

[0131] As the specific aliphatic (thiosulfate) sodium salt derivative, for example, Duralink HTS (sodium hexamethylene-1,6-bis(thiosulfate) dihydrate) manufactured by Flexis can be cited.

[0132] (⑤)Antioxidant

[0133] The rubber composition preferably contains an antioxidant. The content of the antioxidant is, for example, more than 0.5 parts by mass and less than 10 parts by mass, more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component.

[0134] As anti-aging agents, examples include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine, 4,4′-bis(α,α′-dimethylbenzyl)diphenylamine; p-phenylenediamine-based anti-aging agents such as N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N,N′-di-2-naphthyl-p-phenylenediamine; quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-tert-butyl-4-methylphenol, styrenated phenol; bisphenol-based, triphenol-based, polyphenol-based anti-aging agents such as tetrakis[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane, etc. They can be used alone or in combination of two or more.

[0135] It should be noted that as anti-aging agents, products of, for example, Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industrial Co., Ltd., Flexis Co., etc. can be used.

[0136] (⑥) Zinc Oxide

[0137] The rubber composition may contain zinc oxide. The content of zinc oxide is preferably 15 parts by mass or less relative to 100 parts by mass of the rubber component.

[0138] It should be noted that as zinc oxide, known substances can be used, and products of, for example, Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., HAKUSUI TECH Co., Ltd., Sho-Doh Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0139] (⑦) Crosslinking Agents and Vulcanization Accelerators

[0140] The rubber composition preferably contains crosslinking agents such as sulfur. As sulfur, powder sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc. commonly used in the rubber industry can be cited. They can be used alone or in combination of two or more.

[0141] The content of sulfur is preferably 8 parts by mass or less relative to 100 parts by mass of the rubber component.

[0142] It should be noted that as sulfur, products of, for example, Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Ltd., Nippon Karyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0143] As a crosslinking agent other than sulfur, examples include sulfur-containing vulcanizing agents such as TACKROLV200 manufactured by Taoka Chemical Industry Co., Ltd. and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldisulfide)) manufactured by LANXESS Corporation, and organic peroxides such as dicumyl peroxide.

[0144] The rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0145] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazolyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazolyl sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide. They can be used alone or in combination of two or more.

[0146] (⑧) Others

[0147] In the rubber composition, in addition to the above components, additives commonly used in the tire industry, such as fatty acid metal salts, carboxylic acid metal salts, organic peroxides, and anti-reversion agents, can be further blended as needed.

[0148] (c) Use of sustainable materials in each rubber composition

[0149] In the tire of the present invention, when manufacturing other tire components of the above-described belt layer, the specified rubber compositions are also used respectively. However, in consideration of the strong requirements for environmental protection in recent years, it is preferable to use sustainable materials as the materials constituting these rubber compositions.

[0150] (C-1) Rubber material

[0151] For example, raw materials (monomers) of synthetic rubbers such as SBR and BR can be replaced with recycled raw materials from rubber products such as tires or non-rubber products such as polystyrene instead of petroleum sources.

[0152] As the monomer obtained by recycling (recycled monomer), there is no particular limitation, and examples thereof include recycled butadiene, recycled aromatic vinyl monomer, etc. As the butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. In addition, as the aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be mentioned. Among them, recycled butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) from recycling are preferably used as raw materials.

[0153] As the method for producing the recycled monomer, there is no particular limitation, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, as the method for producing the recycled naphtha, there is no particular limitation, and for example, rubber products such as tires can be decomposed under high temperature and high pressure, decomposed by microwave, or extracted after mechanical pulverization.

[0154] In addition, the raw materials (monomers) of synthetic rubbers such as SBR and BR can be derived from biomass. As the monomer derived from biomass (biomass monomer), there is no particular limitation, and examples thereof include butadiene derived from biomass, aromatic vinyl monomer derived from biomass, etc. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the above-mentioned aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be mentioned. In addition, the method for producing the biomass monomer is not particularly limited, and examples thereof include methods based on biological and / or chemical and / or physical conversion of animals and plants. As the biological conversion, fermentation using microorganisms is representative, and as the chemical and / or physical conversion, conversion using a catalyst, conversion using high heat, conversion using high pressure, conversion using electromagnetic waves, conversion using a critical liquid, and combinations thereof can be mentioned. As the biomass sources of these monomers, sugar or wood, plant residues after obtaining useful components, plant-derived ethanol, biomass naphtha, etc. can be mentioned.

[0155] As the polymer synthesized from the biomass monomer component (biomass polymer), there is no particular limitation, and examples thereof include polybutadiene rubber synthesized from butadiene derived from biomass, aromatic vinyl monomer / butadiene copolymer synthesized from butadiene derived from biomass and / or aromatic vinyl monomer derived from biomass, etc. As the above-mentioned aromatic vinyl monomer / butadiene copolymer, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be mentioned, for example.

[0156] It should be noted that whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D 6866-10.

[0157] pMC refers to that of the specimen14 The ratio of the concentration of 14 C to the concentration of carbon in the modern standard reference is used as an index to represent the biomass ratio of a compound (rubber). The significance of this value is as follows.

[0158] In one mole (6.02×10 23 atoms) of carbon, there are approximately one trillionth of ordinary carbon atoms, that is, about 6.02×10 11 atoms 14 of 14 C. 14 C is called a radioactive isotope with a half-life of 5730 years and it decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere is taken in and fixed by plants, etc., in fossil fuels such as coal, oil, and natural gas that have passed more than 226,000 years, all the 14 C elements contained in these substances at the beginning of fixation have decayed. Therefore, in the 21st century, there is no 14 C element in fossil fuels such as coal, oil, and natural gas at all. Therefore, there is also no

[0159] C element in chemical substances produced from these fossil fuels. 14 On the other hand, cosmic rays undergo nuclear reactions in the atmosphere and continuously generate 14 C, which is in balance with the decrease caused by radioactive decay. The amount of 14 C in the earth's atmospheric environment is a certain amount. Therefore, the -12 C concentration of substances from biomass resources in the current material cycle is about 1×10

[0160] This 14 C is usually measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, the 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 C) are measured. In the measurement, the 14 C concentration in the circulating carbon in nature in 1950 is used as 14The reference for the C concentration is the modern standard reference. As a specific reference material, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (the radioactivity intensity of 14 C in every 1 g of carbon) is separated into each carbon isotope, corrected to a certain value for 13 C, and decay correction is carried out from 1950 AD to the measurement date. The value obtained is used as the value of the standard 14 C concentration (100%). The ratio of this value to the value of the actually measured sample becomes the pMC value.

[0161] Therefore, if rubber is made from materials that are 100% derived from biomass (natural system), although there are regional differences, etc., it shows a value of about 110 pMC (currently, it mostly does not reach 100 under normal conditions). On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, it shows a value of approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%.

[0162] In summary, from the aspect of environmental protection, it is suitable to use materials such as rubber with a high pMC value, that is, rubber materials with a high biomass ratio, in the rubber composition.

[0163] In addition, as the rubber material, vulcanized rubber particles are also preferably used.

[0164] Vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder specified in JIS K 6316:2017 can be used, etc. From the aspects of environmental consideration and cost, recycled rubber powder made from crushed waste tires, etc., is preferred. They can be used alone or in combination of two or more.

[0165] As the vulcanized rubber particles, there is no particular limitation, and they can be non-modified vulcanized rubber particles or modified vulcanized rubber particles.

[0166] As commercially available products of vulcanized rubber particles, products of, for example, Lehigh Company, Murakami Rubber Industry Co., Ltd., etc. can be used.

[0167] (C-2) Silica

[0168] Silica is usually contained in the rubber composition as a reinforcing filler, but it is also preferred to use sustainable silica instead of raw materials from minerals such as quartz.

[0169] As the silica, there is no particular limitation, and silica commonly used in the tire industry such as silica prepared by the dry method (anhydrous silica) and silica prepared by the wet method (hydrous silica) can be used. As the raw material of silica, there is no particular limitation. For example, it can be a raw material of mineral origin such as quartz, or a raw material of biological origin such as rice husk (for example, silica based on biomass materials such as rice husk), and silica recycled from products containing silica can also be used. Among them, hydrous silica prepared by the wet method is preferred because of the large number of silanol groups. These silicas can be used alone or in combination of two or more.

[0170] Silica based on biomass materials can be obtained, for example, as follows: Silicate is extracted from rice husk ash obtained by burning rice husk using a sodium hydroxide solution, and the precipitate of silica generated by reacting with sulfuric acid is filtered, washed with water, dried, and pulverized in the same manner as existing wet silica using the silicate, whereby it can be obtained.

[0171] Silica recycled from products containing silica can use, for example, silica recovered from products containing silica such as semiconductor and other electronic components, tires, desiccants, and filter materials such as diatomaceous earth. In addition, as the recovery method, there is no particular limitation, and thermal decomposition, decomposition using electromagnetic waves, etc. can be cited. Among them, silica recovered from semiconductor and other electronic components or tires is preferred.

[0172] If silica crystallizes, it is insoluble in water and the silicic acid as its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Internet Journal B / 2019, vol. 6, p. 216-222, etc.).

[0173] The amorphous silica extracted from rice husk can use commercially available amorphous silica such as that from Wilmar Corporation.

[0174] (C-3) Carbon black

[0175] Furthermore, carbon black is usually also contained in the rubber composition as a reinforcing filler, and as such carbon black, sustainable carbon black is also preferably used.

[0176] As the carbon black, there is no particular limitation, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw material of the carbon black may be biomass materials such as lignin and vegetable oil, or may be pyrolysis oil obtained by pyrolyzing waste tires. In addition, the carbon black can be manufactured by combustion such as the furnace method, or can be manufactured by hydrothermal carbonization (HTC), or can also be manufactured by pyrolysis of methane based on the thermal cracking carbon black method, etc. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, LION Corporation, Nippon Steel Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. They can be used alone or in combination of two or more.

[0177] (C-4) Oil

[0178] As the oil commonly used as a softener, examples include processing oil, vegetable oil, animal oil, etc. As the processing oil, examples include paraffinic processing oil (mineral oil), naphthenic processing oil, aromatic processing oil, etc. Specific examples of the processing oil include, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. In addition, for environmental countermeasures, processing oil with a low content of polycyclic aromatic compounds (PCA) can also be used. As the above-mentioned low-PCA content processing oil, examples include MES, TDAE, heavy naphthenic oil, etc. In addition, from the aspect of life cycle assessment, oil refined from waste oil used in a rubber mixer or an engine, or waste cooking oil used in a cooking shop can also be used.

[0179] Also, as specific vegetable oils, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, fragrant oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc. can be cited. In addition, as vegetable oils, refined oils (such as salad oil) refined from the above oils, transesterified oils obtained by transesterifying the above oils, solidified oils obtained by hydrogenating the above oils, heat-polymerized oils obtained by heat-polymerizing the above oils, oxidative polymerized oils obtained by oxidizing the above oils, waste cooking oils recovered after being used as edible oils, etc. can also be cited. It should be noted that vegetable oils can be liquid or solid at normal temperature (25°C).

[0180] The vegetable oil preferably contains acylglycerol, and more preferably contains triacylglycerol. Here, acylglycerol refers to a compound in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. As acylglycerol, there is no particular limitation, and it can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. In addition, acylglycerol can be a monomer, a dimer, or a polymer of trimer or higher. It should be noted that acylglycerols of dimer or higher can be obtained by heat polymerization or oxidative polymerization, etc. Also, acylglycerol can be liquid or solid at normal temperature (25°C).

[0181] As a method for confirming whether the above acylglycerol is contained in the rubber composition, there is no particular limitation, and it can be confirmed by 1 1H-NMR measurement. For example, the rubber composition mixed with triacylglycerol is immersed in deuterated chloroform at normal temperature (25°C) for 24 hours. After removing the rubber composition, 1H-NMR is measured at room temperature. 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed, and it is speculated that these signals are signals from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. It should be noted that "around" in this paragraph refers to a range of ±0.10 ppm.

[0182] As the above fatty acid, there is no particular limitation, and it can be an unsaturated fatty acid or a saturated fatty acid. As unsaturated fatty acids, monovalent unsaturated fatty acids such as oleic acid, and polyvalent unsaturated fatty acids such as linoleic acid and linolenic acid can be cited. In addition, as saturated fatty acids, butyric acid, lauric acid, etc. can be cited.

[0183] Among them, as the above-mentioned fatty acid, it is preferred to contain a fatty acid with few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, preferably oleic acid. As the vegetable oil containing such fatty acids, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid can be used, and a vegetable oil modified by transesterification can also be used. In addition, in order to produce a vegetable oil containing such fatty acids, plants can also be improved by variety improvement, genetic recombination, genome editing, etc.

[0184] As the vegetable oil, for example, commercially available vegetable oils from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Olisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Manufacturing Co., Ltd., Fuji Kosan Co., Ltd., Nissin Oillio Group Ltd., etc. can be used.

[0185] (C-5) Softeners other than oils

[0186] In the rubber composition, as a softener that imparts plasticity to the rubber component, in addition to the above-mentioned oil, it also contains a softener that is liquid (liquid) at room temperature (25°C) and a softener that is solid at room temperature (25°C). Examples of such softeners include resin components, liquid polymers, ester plasticizers, etc. These softeners can come from petroleum, biomass, or naphtha recycled from rubber products and non-rubber products (sustainable softeners). In addition, low molecular weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components can also be used as softeners. These softeners can be used alone or in combination of two or more.

[0187] (C-6) Wax

[0188] The rubber composition usually contains wax. The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include petroleum wax, mineral wax, synthetic wax, and plant-derived wax. Among them, petroleum wax and plant-derived wax are preferred, and petroleum wax is more preferred. Examples of plant-derived wax include rice bran wax, carnauba wax, and candelilla wax. Examples of petroleum wax include paraffin wax, microcrystalline wax, and their selected special waxes, preferably paraffin wax. Examples of wax include commercially available waxes from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seira Co., Ltd., and Paramelt. These waxes can be used alone or in combination of two or more.

[0189] (C-7) Anti-aging agent

[0190] An anti-aging agent is usually contained in the rubber composition. There is no particular limitation on the anti-aging agent, and examples thereof include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based anti-aging agents such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylxyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol-based, triphenol-based, and polyphenol-based anti-aging agents such as tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. Among them, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. As commercially available products, products of, for example, Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., Ltd. can be used.

[0191] It should be noted that in the rubber composition, various materials containing carbon atoms (such as rubber, oil, resin, vulcanization accelerator, anti-aging agent, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the blend of the present invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process for synthesizing methane from carbon dioxide can be converted.

[0192] (2) Preparation of rubber composition

[0193] The above rubber composition can be prepared by a general method, for example, a manufacturing method including a basic kneading process of kneading rubber components and fillers such as carbon black, and a refining kneading process of kneading the kneaded product obtained in the above basic kneading process and a crosslinking agent.

[0194] Kneading can be carried out using a known (closed type) kneading machine such as a Banbury mixer, a kneader, an open mill, etc.

[0195] The kneading temperature in the basic kneading process is, for example, over 50°C and less than 200°C, and the kneading time is, for example, over 30 seconds and less than 30 minutes. In the basic kneading process, in addition to the above components, compounding agents used in the existing rubber industry, such as softening agents like oil, zinc oxide, anti-aging agents, wax, vulcanization accelerators, etc., can also be appropriately added as needed and kneaded.

[0196] In the refining kneading process, the kneaded material obtained in the above basic kneading process and a cross-linking agent are kneaded. The kneading temperature in the refining kneading process is, for example, over room temperature and less than 80°C, and the kneading time is, for example, over 1 minute and less than 15 minutes. In the refining kneading process, in addition to the above components, vulcanization accelerators, zinc oxide, etc. can also be appropriately added as needed and kneaded.

[0197] At this time, by adjusting the compounding amounts of the above compounding materials, the complex elastic modulus E can be appropriately adjusted. * . For example, by increasing the content of fillers such as carbon black, reducing the particle size of the fillers, reducing the content of softening agent components such as oil and resin, increasing the content of sulfur and accelerators, etc., the complex elastic modulus E can be increased. * . On the contrary, by reducing the content of fillers such as carbon black, increasing the content of plasticizer components such as oil and resin, reducing the content of sulfur and accelerators, etc., the complex elastic modulus E can be decreased. * .

[0198] 3. Manufacture of the belt layer cord fabric

[0199] The belt layer (belt layer cord fabric) can be manufactured by applying the above-obtained rubber composition to both sides of cords (steel cords) arranged side by side at a specified interval (density).

[0200] It should be noted that before applying the rubber composition, it is preferable to previously coat the surface of the cords with an adhesive composition to form a coating layer. By making this coating layer function as an adhesive layer, the rubber composition and the cords can be sufficiently adhered.

[0201] As the adhesive composition, an adhesive composition containing a polybenzoxazine compound containing the units shown in the following (Chemical Formula 1) to (Chemical Formula 4) exhibits excellent adhesiveness to both the rubber composition and the cords, and is therefore preferable.

[0202] [Chemical Formula 1]

[0203]

[0204] [Chemical Formula 2]

[0205]

[0206] [Chemical Formula 3]

[0207]

[0208] [Chemical Formula 4]

[0209]

[0210] It should be noted that in the above (Chemical Formula 1) and (Chemical Formula 2), X1 is a hydrocarbon selected from aliphatic, alicyclic, and aromatic hydrocarbons and combinations thereof, and may have any one of the heteroatoms S, O, N, and P and a structure in which these heteroatoms are continuously connected. Further, X2 has an (S)n structure in which n (1 to 8) S atoms are connected, and may have a hydrocarbon selected from aliphatic, alicyclic, and aromatic hydrocarbons, and any one and / or combinations thereof of S, O, N, and P. Additionally, in (Chemical Formula 3) and (Chemical Formula 4), X1 is a hydrocarbon selected from aliphatic, alicyclic, and aromatic hydrocarbons and combinations thereof, and has an (S)n structure in which n (1 to 8) S atoms are connected.

[0211] The above adhesive composition can be produced, for example, by a known method described in US2020 / 0290402 Gazette (Japanese Patent Application Laid-Open No. 2019-507805). After applying a coating solution of the obtained adhesive composition to the surface of the cord and drying, heat crosslinking is performed, whereby an adhesive layer can be formed on the surface of the cord.

[0212] 4. Manufacture of Tire

[0213] The tire of the present embodiment can be produced as an unvulcanized tire by molding the above-obtained belt layer (belt cord ply) together with other tire components on a tire molding machine by a conventional method.

[0214] Specifically, on a molding drum, an inner liner as a component for ensuring airtightness of the tire, a carcass as a component for bearing the load, impact, and inflation pressure of the tire, a belt layer as a component for strongly clamping the carcass and improving the tread rigidity, etc. are wound. While fixing both ends of the carcass at both side edges, a bead portion as a component for fixing the tire to a rim is arranged. After molding into a ring shape, the tread is attached to the central portion of the outer periphery, and the sidewall is attached to the radially outer side to form a sidewall portion, thereby producing an unvulcanized tire.

[0215] It should be noted that in the present embodiment, as described above, from the aspect of improving the binding force to the tread during driving and easily suppressing the growth of the outer diameter, the belt layer may also be composed of multiple belt cord plies. In this case, in the vulcanized tire, the average distance D (mm) between the cords of the belt cord plies in the tread portion is preferably 0.6 mm or less. Additionally, it is preferably arranged such that the angle formed by the cords with each other and a straight line parallel to the tire circumferential direction in the tread portion is 10° or more and 35° or less, and the cords of adjacent belt cord plies cross each other.

[0216] It should be noted that the angle of the above-mentioned cord is the angle of the cord relative to the tire circumferential direction in the state where no air is filled into the tire, and can be confirmed by peeling the tread portion from the radial outside of the tire.

[0217] Then, the tire is obtained by heating and pressurizing the above-mentioned uncured tire in a vulcanizer. The vulcanization process can be implemented by applying known vulcanization means. As the vulcanization temperature, for example, it is more than 120°C and less than 200°C, and the vulcanization time is, for example, more than 5 minutes and less than 15 minutes.

[0218] In the tire obtained above, as described above, by appropriately controlling the cord diameter of the belt layer and the cobalt content in the rubber composition, and satisfying D / E * <0.1×C + 0.170, each effect is synergistically multiplied, so that an improvement in the comprehensive performance of low fuel consumption and durability can be achieved.

[0219] Moreover, the tire of the present invention can be suitably used as a passenger car tire, a large passenger car tire, a large SUV tire, a small truck tire, etc.

[0220] Examples

[0221] The following shows examples (examples) considered to be preferable at the time of implementation, but the scope of the present invention is not limited to these examples.

[0222] For tires having substantially the same constitution except for the belt layers of each specification shown in Table 1 Figure 1 (tire size: 195 / 65R15) were studied, and regarding low fuel consumption and durability, calculations were made based on the evaluation method described later, and the results are shown together in the lower part of Table 1.

[0223] 1. Manufacture of rubber composition

[0224] First, the rubber composition constituting the belt layer is manufactured.

[0225] (1) Blending materials

[0226] (a) Rubber components

[0227] NR: RSS3

[0228] (b) Blending materials other than rubber components

[0229] (①) Carbon black - 1: SHOBLACK N660 manufactured by Cabot Japan Co., Ltd.

[0230] (BET specific surface area: 35m 2 / g, average particle size: 40nm)

[0231] (②) Carbon black - 2: SHOBLACK N326 manufactured by Cabot Japan

[0232] (BET specific surface area: 78 m 2 / g, average particle size: 30 nm)

[0233] (③) Oil: Diana Process AH - 24 (aromatic oil) manufactured by Idemitsu Kosan Co., Ltd.

[0234] (④) Cobalt organic acid: COST - F manufactured by DIC Corporation

[0235] (Cobalt stearate, cobalt content: 9.5 mass%)

[0236] (⑤) Antioxidant: ANTAGE RD manufactured by Kawaguchi Chemical Industry Co., Ltd.

[0237] (2,2,4 - trimethyl - 1,2 - dihydroquinoline)

[0238] (⑥) Zinc oxide: Zinc White No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd.

[0239] (⑦) Sulfur: Powder sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.

[0240] (⑧) Vulcanization accelerator: NOCCELER DZ manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0241] (N,N - dicyclohexyl - 2 - benzothiazolyl sulfenamide)

[0242] (2) Manufacture of rubber composition

[0243] According to the compounding content shown in Table 1, using a Banbury mixer, materials other than sulfur and vulcanization accelerator were kneaded at 150 °C for 5 minutes to obtain a kneaded product. It should be noted that each compounding amount is in parts by mass.

[0244] Next, sulfur and vulcanization accelerator were added to the above - obtained kneaded product, and it was kneaded at 80 °C for 5 minutes using an open mill to obtain a rubber composition.

[0245] 2. Manufacture of tires

[0246] First, on both sides of a steel cord having the specifications shown in Table 1, the same amount of the above - obtained rubber composition was coated to produce a belt ply, and 2 sheets were laminated to form a belt layer.

[0247] After that, it was bonded together with other tire components to form an unvulcanized tire, and it was press - vulcanized at 170 °C for 10 minutes to manufacture each test tire shown in Table 1 (Examples 1 to 8 and Comparative Examples 1 to 4).

[0248] 3. Calculation of Parameters

[0249] For the above rubber composition, a rubber test piece for viscoelasticity measurement with a length of 40 mm, a width of 4 mm, and a thickness of 1 mm was produced. Using the EPLEXOR series manufactured by GABO, the complex elastic modulus E was measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tension. * .

[0250] Furthermore, each parameter shown in Table 1 (D / E * −0.1×C, E×S, E×B) was calculated.

[0251] 4. Performance Evaluation (1)

[0252] Evaluation of Low Fuel Consumption

[0253] Using a rolling resistance test machine, for each test tire, the rolling resistance coefficient RRC (Rolling Resistance Coefficient) was measured when traveling on a drum at a speed of 80 km / h under the following conditions.

[0254] Rim used: 15×6J

[0255] Inner pressure: 210 kPa

[0256] Load: 4.35 kN

[0257] Next, taking the result in Comparative Example 1 as 100, it was exponentiated based on the following formula as the evaluation of low fuel consumption. The larger the value, the more excellent the low fuel consumption.

[0258] Low fuel consumption evaluation = [(Result of Comparative Example 1) / (Result of test tire)]×100

[0259] (2) Evaluation of Durability

[0260] Each test tire was assembled onto a rim (size = 15×6J), filled with air, and after adjusting the inner pressure to 230 kPa, it was installed on a drum running test machine, and a longitudinal load of 5.88 kN was applied. Starting from 210 km / h, the speed was gradually increased in stages of 10 km / h, and the time until the tire was damaged was measured.

[0261] Next, taking the result in Comparative Example 1 as 100, it was exponentiated based on the following formula as an index of durability for evaluation. The larger the value, the longer the time until damage, indicating the more excellent the durability.

[0262] Durability evaluation = [(Result of test tire) / (Result of Comparative Example 1)]×100

[0263] (3) Comprehensive performance evaluation

[0264] Sum up the above low fuel consumption evaluation and durability evaluation as the comprehensive performance evaluation.

[0265] [Table 1]

[0266]

[0267] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope of the present invention.

[0268] The present invention (1) relates to a tire having a belt layer formed by covering a belt layer cord with a rubber composition, and the tire is characterized in that

[0269] The above belt layer cord is composed of 4 filaments,

[0270] In the above rubber composition, the cobalt amount is less than 0.15 parts by mass relative to 100 parts by mass of the rubber component,

[0271] The diameter D (mm) of the above belt layer cord, the complex elastic modulus E * (MPa) measured under the conditions of temperature: 70 °C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tension, and the cobalt amount C (parts by mass) relative to 100 parts by mass of the rubber component in the above rubber composition satisfy the following formula.

[0272] D / E * <0.1 × C + 0.170

[0273] The present invention (2) The tire according to the present invention (1), characterized in that the cobalt amount in the above rubber composition is less than 0.10 parts by mass relative to 100 parts by mass of the rubber component.

[0274] The present invention (3) The tire according to the present invention (2), characterized in that the cobalt amount in the above rubber composition is less than 0.05 parts by mass relative to 100 parts by mass of the rubber component.

[0275] The present invention (4) The tire according to the present invention (3), characterized in that the cobalt amount in the above rubber composition is less than 0.01 parts by mass relative to 100 parts by mass of the rubber component.

[0276] The present invention (5) The tire according to the present invention (4), characterized in that the cobalt amount in the above rubber composition is less than 0.005 parts by mass relative to 100 parts by mass of the rubber component.

[0277] The present invention (6) relates to a tire in any combination with any one of the present inventions (1) to (5), characterized in that, in the tire width direction of the belt layer cord, the number of cords E (pieces) per 50 mm width and the surface area S (mm 2 / mm) per unit length (1 mm) satisfy the following formula.

[0278] E × S > 60

[0279] The present invention (7) relates to a tire in any combination with any one of the present inventions (1) to (5), characterized in that, in the tire width direction of the belt layer cord, the number of cords E (pieces) per 50 mm width and the bending rigidity B (g·cm) satisfy the following formula.

[0280] E × B > 1600

[0281] The present invention (8) relates to a tire in any combination with any one of the present inventions (1) to (5), characterized in that, in the above rubber composition, the carbon black having a BET specific surface area of 45 m 2 / g or more is contained in an amount of 5 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the rubber component.

[0282] Symbol Explanation

[0283] 1 Tire

[0284] 2 Tread

[0285] 3 Sidewall

[0286] 4 Bead

[0287] 5 Bead core

[0288] 6 Carcass

[0289] 6A Carcass ply

[0290] 6a Inner main body

[0291] 6b Outer folded-back part

[0292] 7 Belt

[0293] 7A First belt ply

[0294] 7B Second belt ply

[0295] 8 Bead filler

[0296] 10 Belt cord

[0297] C Center line

Claims

1. A tire comprising a belt layer formed by coating a belt layer cord with a rubber composition, wherein: The belt layer cord is composed of 4 filaments. In the rubber composition, the amount of cobalt is less than 0.15 parts by mass relative to 100 parts by mass of the rubber component. The diameter D of the belt cord, the complex elastic modulus E of the rubber composition measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tension * , and the amount C of cobalt in the rubber composition relative to 100 parts by mass of the rubber component satisfies the following formula, D / E * <0.1×C+0.170 in, The diameter D is in mm, and the complex elastic modulus E * The unit of is MPa, and the unit of the cobalt amount C is part by mass.

2. The tire according to claim 1, characterized in that The amount of cobalt in the rubber composition is less than 0.10 parts by mass based on 100 parts by mass of the rubber component.

3. The tire according to claim 2, characterized in that The amount of cobalt in the rubber composition is less than 0.05 parts by mass based on 100 parts by mass of the rubber component.

4. The tire according to claim 3, characterized in that The amount of cobalt in the rubber composition is less than 0.01 parts by mass based on 100 parts by mass of the rubber component.

5. The tire according to claim 4, characterized in that The amount of cobalt in the rubber composition is less than 0.005 parts by mass based on 100 parts by mass of the rubber component.

6. The tire according to any one of claims 1 to 5, characterized in that In the tire width direction of the belt layer cords, the number of cords E per 50 mm width and the surface area S per unit length satisfy the following formula: E×S>60 The unit of the cord number E is root, the unit length is 1 mm, and the unit of the surface area S is mm. 2 / mm.

7. The tire according to any one of claims 1 to 5, characterized in that In the tire width direction of the belt layer cords, the number of cords E per 50 mm width and the bending rigidity B satisfy the following formula: E×B>1600 The unit of the cord number E is root, and the unit of the bending rigidity B is g·cm.

8. The tire according to any one of claims 1 to 5, characterized in that In the rubber composition, the BET specific surface area is 45 m 2 / g or more of carbon black is contained in an amount of 5 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the rubber component.

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