Tire

Abstract

The invention provides a tire capable of further improving operation stability. A tire is provided with a carcass section and a belt section, in which a carcass ply constituting the carcass section is formed using ply cords having a linear density of more than 4400 dtex, and the belt section is formed by overlapping at least two layers of belt layers using, as the belt cords, a steel cord comprising one filament. Further, the diameter Pr (mm) of the ply cords, the diameter Br (mm) of the belt cords, and the tire radial distance Bg (mm) between the belt cords in adjacent belt layers satisfy the following formula. (Br + Bg) / Pr < = 1.00.

Description

Technical Field

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

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

[0003] Prior Art Documents

[0004] Patent Documents

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

[0006] Problems to be Solved by the Invention

[0007] The problem of the present invention is to further improve the handling stability.

[0008] Means for Solving the Problems

[0009] The present invention relates to a tire including a carcass portion and a belt layer portion, characterized in that

[0010] the carcass ply forming the carcass portion is a carcass ply formed of carcass ply cords having a linear density exceeding 4400 dtex,

[0011] the belt layer portion is formed by overlapping at least two layers of belt layers, and the belt layer uses steel cord formed of one filament as the belt layer cord,

[0012] Further, the diameter Pr (mm) of the carcass ply cord, the diameter Br (mm) of the belt layer cord, and the radial distance Bg (mm) between the belt layer cords in adjacent belt layers satisfy the following formula.

[0013] (Br + Bg) / Pr ≤ 1.00

[0014] Advantages of the Invention

[0015] According to the present invention, it is possible to further improve the handling stability. Brief Description of the Drawings

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

[0017] [1] Features of the Tire of the Present Invention

[0018] First, the features of the tire of the present invention will be described.

[0019] 1. Outline

[0020] The tire of the present invention is a tire having a carcass portion and a belt layer portion. Moreover, the carcass ply constituting the carcass portion is a carcass ply formed using carcass ply cords having a linear density exceeding 4400 dtex, and the belt layer portion is formed by overlapping at least two or more belt layers, and this belt layer uses steel cord composed of one filament as the belt layer cord. Further, the diameter Pr (mm) of the carcass ply cord, the diameter Br (mm) of the belt layer cord, and the radial distance of the tire (belt layer thickness) Bg (mm) between the belt layer cords in adjacent belt layers satisfy the following formula.

[0021] (Br + Bg) / Pr ≤ 1.00

[0022] By having these features, as described later, it is possible to further improve the handling stability.

[0023] 2. Mechanism of effect manifestation in the tire of the present invention

[0024] Regarding the mechanism of the above-described effect manifestation in the tire of the present invention, the following can be considered.

[0025] (1) Carcass portion

[0026] In the tire of the present invention, the carcass ply constituting the carcass portion is a carcass ply formed using carcass ply cords having a linear density (also referred to as "total fineness") exceeding 4400 dtex.

[0027] By forming the carcass ply using carcass ply cords having a linear density exceeding 4400 dtex, which is coarser than the existing carcass ply cords having a linear density of about 2200 to 4400 dtex, it is possible to increase the lateral spring constant and change (reduce) the degree of flexure generated in the sidewall portion during running. Therefore, it is considered that the handling stability can be improved. It should be noted that the linear density of the carcass ply cord is preferably 6600 dtex or less.

[0028] It should be noted that the linear density of the above-described carcass ply cord can be measured according to the method specified in JIS L1017:2002.

[0029] The carcass portion may be composed of two or more carcass plies, but is preferably composed of one ply. By folding back such a carcass portion around the bead core from the inside to the outside and locking it, it is possible to sufficiently reduce the axial bending rigidity, and when there is an outer inclination during turning, the sidewall portion can be sufficiently bent, and more of the tread surface can contact the ground. Therefore, it is considered that the handling stability can be improved. It should be noted that in the embodiments described later, one or more carcass plies are used.

[0030] In addition, by forming such a carcass portion, it is considered that low fuel consumption of the tire can be achieved.

[0031] (2) Belt layer part

[0032] The belt layer part is formed by overlapping at least two layers of belt layers formed by using steel cord as the belt layer cord, which is composed of one filament (1×1 structure). By doing so, the cord diameter can be reduced, and the thickness of the rubber adhered to the belt layer cord (adhesive thickness) can be thinned. Therefore, it is considered that the weight reduction of the tire can be achieved.

[0033] Here, the filament constituting the belt layer cord preferably has a circular cross-sectional shape, but it can also be elliptical. In addition, the filament is preferably uncorrugated and untwisted, and plating treatment can also be performed.

[0034] In addition, in the present invention, the diameter Pr (mm) of the carcass cord, the diameter Br (mm) of the belt layer cord, and the distance Bg (mm) between the belt layers satisfy the following formula.

[0035] (Br + Bg) / Pr ≤ 1.00

[0036] Thereby, the thickness of the belt layer part can be made thinner than that of the carcass ply, the shear rigidity during driving can be increased, and the response force to the lateral force can be improved. Therefore, it is considered that the improvement of handling stability can be achieved, and the weight reduction of the tire can be achieved.

[0037] It should be noted that the above ((Br + Bg) / Pr) is more preferably 0.95 or less, and further preferably 0.90 or less. On the other hand, there is no particular limitation on the lower limit, and it is preferably 0.60 or more, and more preferably 0.65 or more.

[0038] As described above, in the present invention, by appropriately forming the carcass part and the belt layer part, the above-mentioned various effects are synergistically multiplied, and therefore it is considered that the improvement of handling stability can be achieved.

[0039] It should be noted that in the above text, regarding the diameter of the cord, in the case where the circumscribed circle of the cross-section perpendicular to the cord extension direction is a perfect circle, it refers to the diameter of the circumscribed 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).

[0040] In addition, regarding the radial distance (distance between belt layers) Bg between the belt layer cords in adjacent belt layers, when each of the belt layer cords in both belt layers is located on the equator in the tire meridian section, the radial distance between the cross-sections of these two belt layer cords is measured on the equator, and thus it can be obtained. And in the case where only one of the belt layer cords is on the equator and the other belt layer cord is not on the equator, the radial distance between the belt layer cord closest to the equator and the belt layer cord located on the equator is measured, and thus it can be obtained.

[0041] [2]A more preferred embodiment of the tire of the present invention

[0042] By adopting the following methods, the tire of the present invention can achieve greater effects.

[0043] 1. Cord diameter of the belt layer cords

[0044] In the present invention, the cord diameter of the belt layer cords is preferably 0.29 mm or more and 0.42 mm or less. Thereby, further thinning of the belt layer portion can be achieved, so it is considered that further improvement in handling stability can be achieved, and further weight reduction of the tire can be achieved. More preferably, it is 0.32 mm or more and 0.38 mm or less.

[0045] 2. Densities in the carcass portion and the belt layer portion

[0046] In the present invention, if the number of cords per 50 mm width (density) E in the tire width direction of the carcass portion CA and the number of cords per 50 mm width (density) E in the tire width direction of the belt layer portion BE are made to have a difference such that the bending rigidities of the carcass portion and the belt layer portion are close values, then the balance between the flexure of the sidewall portion and the grounding property of the tread portion can be improved, so it is considered that further improvement in handling stability can be achieved.

[0047] Specifically, by making the difference between the density E CA of the carcass portion and the density E BE of the belt layer portion 15 or less, it is considered that further improvement in handling stability can be achieved. That is, if the following formula is satisfied, it is considered that further improvement in handling stability can be achieved.

[0048] |E CA - E BE | ≤ 15

[0049] It should be noted that the above |E CA - E BE | is more preferably 12 or less, further preferably 8 or less, and particularly preferably 5 or less.

[0050] 3. Density of the belt layer portion

[0051] In the present invention, as the density of the belt layer portion, it is preferably 45 cords or less, and more preferably 40 cords or less.

[0052] By reducing the density in this way, the bending rigidity of the belt layer portion can be reduced, so the grounding property of the tread portion is improved, and it is considered that further improvement in handling stability can be achieved.

[0053] 4. Intermediate elongation rate and thermal shrinkage rate of the ply cords

[0054] In the present invention, the cords of the carcass ply preferably have both a low intermediate elongation rate and a low heat shrinkage rate.

[0055] From the aspect of handling stability, as the cords of the carcass ply, organic fiber cords such as rayon, polyamide synthetic fiber, and polyester synthetic fiber, which have a low intermediate elongation rate and a high modulus, are generally suitable. However, these fiber cords shrink thermally during vulcanization, resulting in a decrease in modulus. Therefore, it is considered that by reducing both the intermediate elongation rate and the heat shrinkage rate, an increase in modulus in the vulcanized tire can be achieved, thereby enabling further improvement in handling stability.

[0056] Specifically, the sum of the intermediate elongation rate (%) and the heat shrinkage rate (%) of the cords of the carcass ply is preferably less than 8.3, more preferably 7.5 or less. Thereby, the modulus in the vulcanized tire can be increased, and the lateral spring constant can be raised. Therefore, it is considered that the flexure generated in the sidewall portion can be reduced, and further improvement in handling stability can be achieved.

[0057] It should be noted that the intermediate elongation rate (%) of the cord can be obtained from the elongation rate (%) at a load of 132 N in the "load-elongation" curve of the cord obtained in an environment at room temperature (25°C ± 2°C) according to the "JIS L1017:2002 Test Methods for Chemical Fiber Tyre Cords".

[0058] In addition, the heat shrinkage rate (%) of the cord can be obtained from the ratio y / x (%) of the shrinkage amount y (mm) to the length x (mm) of the cord before placement (the cord of the carcass ply) when the cord is placed for 30 minutes at a temperature of 180°C in a load-free state according to the "JIS L1017:2002 Test Methods for Chemical Fiber Tyre Cords".

[0059] [3] Embodiment

[0060] Hereinafter, the present invention will be specifically described based on the embodiment.

[0061] 1. Tire of the present embodiment

[0062] 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.

[0063] 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.

[0064] It should be noted that a "regular rim" refers to the rim specified for each tire in a standard system including 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.

[0065] Moreover, "regular internal pressure" refers to the air pressure specified for each tire in a standard system including 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 (but above 250 KPa). It should be noted that in the case of multiple regular internal pressures above 250 KPa being recorded, it refers to the minimum value among them.

[0066] As Figure 1 shown, the tire 1 includes: a carcass part 6 from the tread part 2 through the sidewall part 3 to the bead core 5 of the bead part 4; and a belt layer part 7 disposed on the radially outer side of the carcass part 6 and on the inner side of the tread part 2. It should be noted that C is the center line. And Figure 1 in, the description of the chafer ply disposed between the carcass part 6 and the tread part 2 is omitted.

[0067] (1) Carcass part

[0068] The carcass portion 6 is composed of one carcass ply 6A, and is locked by being folded back from the inside to the outside through the bead core 5 of the bead portion 4 around the sidewall portion 3 from the tread portion 2 (1-0 structure).

[0069] It should be noted that Figure 1 In, 6a is the inner main body portion of the carcass ply 6A, 6b is the outer folded-back portion, and a bead filler 8 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.

[0070] The carcass ply 6A is formed by applying a rubber composition for carcass ply of a prescribed thickness to both surfaces of a ply arrangement in which ply cords having a linear density exceeding 4400 dtex are arranged at a prescribed density (not shown).

[0071] By adopting such a carcass portion 6, as described above, it is possible to increase the lateral spring constant and reduce the degree of flexure generated in the sidewall portion during running, and thus it is considered that an improvement in handling stability can be achieved.

[0072] It should be noted that, as described above, as the ply cords, organic fiber cords having a low intermediate elongation rate and a high modulus such as rayon, polyamide synthetic fiber, and polyester synthetic fiber can be suitably used.

[0073] (2) Belt layer portion

[0074] The belt layer portion 7 is disposed radially outside the carcass portion 6 and inside the tread portion 2.

[0075] The belt layer portion 7 is composed of one or more belt layers. Figure 1 In, the belt layer portion 7 is composed of two belt layers, i.e., a first belt layer 7A located radially inside the tire and a second belt layer 7B located outside the first belt layer 7A. It should be noted that three or more belt layers can also be used.

[0076] The belt layer is formed by applying a rubber composition for belt layer of a prescribed thickness to both surfaces of a ply arrangement in which 1×1 structure steel cords (belt layer cords) are arranged at a prescribed density, and is made to have a thickness thinner than that of the carcass ply 6A (not shown).

[0077] By adopting such a belt layer portion 7, as described above, it is possible to achieve low fuel consumption of the tire 1, and the shear rigidity during running increases and the response force to the lateral force improves, and thus an improvement in handling stability can be achieved.

[0078] 2. Use of sustainable materials

[0079] In the tire of the present invention, the above-mentioned belt layer and carcass ply are used, and a prescribed rubber composition is used respectively when manufacturing other tire components. However, in consideration of the strong requirements for environmental protection in recent years, it is preferable to use sustainable materials as the materials constituting the rubber composition.

[0080] (1) Rubber material

[0081] For example, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR can be replaced with raw materials recycled from rubber products such as tires or non-rubber products such as polystyrene instead of raw materials from underground resources such as petroleum or natural gas.

[0082] As the monomers obtained by recycling (recycled monomers), there is no particular limitation, and examples include recycled polyisoprene, recycled butadiene, recycled aromatic vinyl monomers, etc. As 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, it is preferable to use recycled isoprene (recycled isoprene), recycled butadiene, and / or recycled styrene (recycled styrene) as the raw materials.

[0083] As the manufacturing method of the recycled monomer, there is no particular limitation, and examples include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, as the manufacturing method of the recycled naphtha, there is no particular limitation. For example, rubber products such as tires can be decomposed under high temperature and high pressure, can be decomposed by microwave, or can be extracted after mechanical pulverization.

[0084] In addition, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR can be derived from biomass. Biomass refers to substances from natural resources such as plants. There is no particular limitation for biomass, and examples include agricultural, forestry, and fishery products, sugars, wood chips, plant residues after obtaining useful components, plant-derived ethanol, biomass naphtha, etc. As the monomers derived from biomass (biomass monomers), there is no particular limitation, and examples include butadiene derived from biomass, aromatic vinyl monomers 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 manufacturing method of the biomass monomer is not particularly limited, and examples include methods based on biological and / or chemical and / or physical conversion of animals and plants. As biological conversion, fermentation using microorganisms is representative, and as chemical and physical conversion, conversion using catalysts, conversion using high heat, conversion using high pressure, conversion using electromagnetic waves, conversion using supercritical fluids, and combinations thereof can be mentioned.

[0085] As the polymer synthesized from biomass monomer components (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, and the like. As the above-mentioned aromatic vinyl monomer / butadiene copolymer, for example, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be mentioned.

[0086] It should be noted that whether the raw material of the polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured according to ASTM D 6866-10.

[0087] pMC refers to the 14 ratio of the 14 C concentration of the sample to the

[0088] C concentration of the modern standard reference, and it is a value used as an index to represent the biomass ratio of a compound. The meaning of this value is as described below. 23 In one mole (6.02×10 11 ), there are about one trillionth of ordinary carbon atoms, that is, about 6.02×10 14 14 C. 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken in and immobilized by plants and the like, it is considered that in fossil fuels such as coal, oil, and natural gas that have passed more than 226,000 years, all of the 14 C elements contained in these substances at the beginning of immobilization have decayed. Therefore, in the present of the 21st century, fossil fuels such as coal, oil, and natural gas do not contain 14 C elements at all. Therefore, chemical substances produced from these fossil fuels also do not contain

[0089] C elements at all. 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 radiation decay, and the amount of 14 C in the earth's atmospheric environment is a certain amount. Therefore, the -12 C concentration of substances derived from biomass resources that are recycled in the current environment is about 1×10 ​

[0090] The 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) is measured. In the measurement, the 14 C concentration in the cyclic carbon in nature in 1950 is used as the 14 C concentration reference, i.e., 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 per 1 g of carbon) is separated into each carbon isotope, corrected to a certain value for 13 C, and decay correction is performed from 1950 AD to the measurement date. The obtained value is used as the standard 14 C concentration value (100%). The ratio of this value to the value of the actually measured sample becomes the pMC value.

[0091] Therefore, if rubber is made from a material that is 100% derived from biomass (natural system), although there are regional differences, etc., it generally does not reach 100 under normal conditions at present, so it shows a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, it generally shows a value of about 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0092] In summary, from the aspect of environmental protection, it is suitable to use rubber and other materials with a high pMC value, that is, rubber and other materials with a high biomass ratio, in the rubber composition.

[0093] In addition, as the rubber material, vulcanized rubber particles are also preferably used.

[0094] Vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder specified in JIS K 6316:2017 can be used. 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.

[0095] As the vulcanized rubber particles, there is no particular limitation. They can be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0096] As commercially available products of vulcanized rubber particles, products of, for example, Lehigh Corporation, Murakami Rubber Industry Co., Ltd. can be used.

[0097] (2) Silica

[0098] The rubber composition usually contains silica as a reinforcing filler, but it is also preferable to use sustainable silica in place of raw materials from minerals such as quartz.

[0099] There is no particular limitation on the silica, and for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), etc., which are commonly used in the tire industry, can be used. There is no particular limitation on the raw material of the silica. For example, it can be a raw material from a mineral source such as quartz, or a raw material from a biological source 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, due to the large number of silanol groups, hydrous silica prepared by a wet method is preferred. These silicas can be used alone or in combination of two or more.

[0100] 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 precipitation 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 this silicate, whereby it can be obtained.

[0101] Silica recycled from products containing silica can be, 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, there is no particular limitation on the recovery method, and examples include thermal decomposition, decomposition using electromagnetic waves, etc. Among them, silica recovered from semiconductor and other electronic components or tires is preferred.

[0102] 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, the crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol. 6, p. 216-222, etc.).

[0103] Amorphous silica extracted from rice husk can be the amorphous silica commercially available from companies such as Wilmar.

[0104] (3) Carbon black

[0105] Furthermore, the rubber composition usually also contains carbon black as a reinforcing filler, and as such carbon black, it is also preferable to use sustainable carbon black (recycled carbon black).

[0106] 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 can be biomass materials such as lignin and vegetable oil, or can be pyrolysis oil obtained by pyrolyzing waste tires. In addition, the manufacturing method of the carbon black can be manufactured by combustion such as the furnace method, can be manufactured by hydrothermal carbonization (HTC), and 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.

[0107] (4) Oil

[0108] As the oil that is usually used as a softening agent for imparting plasticity to the rubber component, for example, mineral oil, vegetable oil, animal oil, etc. can be cited. 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. Mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. As the mineral oil, paraffinic oil (mineral oil), naphthenic oil, aromatic oil, etc. can be cited. As specific examples of the processing oil, 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. can be cited. In addition, for environmental countermeasures, oil with a low content of polycyclic aromatic compounds (PCA) can also be used. As the above-mentioned oil with a low PCA content, MES, TDAE, heavy naphthenic oil, etc. can be cited.

[0109] Further, 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 seed 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. may be cited. In addition, as vegetable oils, refined oils (such as salad oil) obtained by refining the above oils, transesterified oils obtained by transesterifying the above oils, hydrogenated solid oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, waste edible oils recovered after use as edible oils, etc. may also be cited. It should be noted that vegetable oils can be liquid or solid at normal temperature (25°C). These vegetable oils can be used alone or in combination of two or more.

[0110] 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 thermal polymerization or oxidative polymerization, etc. Also, acylglycerol can be liquid or solid at normal temperature (25°C).

[0111] 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, a rubber composition containing 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 the "around" in this paragraph refers to the range of ±0.10 ppm.

[0112] 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.

[0113] Among them, as the above fatty acids, it is preferable to contain fatty acids with fewer double bonds, that is, saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As the vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids can be used, or a modified vegetable oil such as transesterified oil can be used. In addition, in order to produce a vegetable oil containing such fatty acids, plants can also be improved through variety improvement, genetic recombination, genome editing, etc.

[0114] As the vegetable oil, for example, commercially available vegetable oils from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0115] (5) Plasticizers other than oil

[0116] In the rubber composition, as the plasticizer that imparts plasticity to the rubber component, in addition to the above oil, there are also plasticizers that are liquid at 25°C and plasticizers that are solid at 25°C. Examples of such plasticizers include resin components, liquid polymers, ester plasticizers, etc. These plasticizers can be derived from mineral resources such as petroleum and natural gas, can be derived from biomass, or can be derived from naphtha recycled from rubber products and non-rubber products (sustainable plasticizers). In addition, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires or products containing various components can also be used as plasticizers. These plasticizers can be used alone or in combination of two or more.

[0117] (6) Wax

[0118] The rubber composition usually contains wax. There is no particular limitation on the wax, and any wax commonly used in the tire industry can be suitably used. For example, mineral waxes and plant-derived waxes can be cited. Mineral waxes are derived from mineral resources such as petroleum and natural gas, and plant-derived waxes are derived from natural resources such as plants. Among them, mineral waxes are preferred. As plant-derived waxes, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As mineral waxes, for example, paraffin wax, microcrystalline wax, their selected special waxes, etc. can be cited, and paraffin wax is preferred. Waxes can be used, for example, commercially available waxes from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., etc. These waxes can be used alone or in combination of two or more.

[0119] (7) Anti-aging agent

[0120] 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), 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, 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.

[0121] 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.

[0122] 3. Manufacture of tires

[0123] The tire of the present embodiment can be manufactured by a conventional method.

[0124] Specifically, on the forming drum, the inner liner part as a component for ensuring the airtight retention of the tire, the carcass part as a component for bearing the load, impact, and inflation pressure of the tire, the belt layer part as a component for strongly clamping the carcass part and improving the tread rigidity, etc. are wound. While fixing both ends of the carcass ply at both side edges, the bead part as a component for fixing the tire to the rim is arranged. After being formed into a ring shape, by attaching the tread part to the central part of the outer periphery and attaching the sidewall to the radially outer side, the sidewall part is formed, and thus an unvulcanized tire is produced. It should be noted that in the present embodiment, as described above, from the aspect of easily increasing the clamping force on the carcass part during driving and improving the rigidity of the tread part, the belt layer part can be composed of multiple belt layers. At this time, in the vulcanized tire, the belt layer thickness Bg (mm) is preferably 0.6 mm or less.

[0125] Then, the tire is obtained by heating and pressing the above-produced unvulcanized tire in a vulcanizer. The vulcanization process can be implemented by applying known vulcanization means. As the vulcanization temperature, for example, it exceeds 120°C and is less than 200°C, and the vulcanization time is, for example, more than 5 minutes and less than 15 minutes.

[0126] In the tire obtained above, as described above, the carcass part and the belt layer part are appropriately formed, and thus the respective effects are synergistically multiplied, so that the balance between the low fuel consumption of the tire and the improvement of handling stability can be appropriately achieved.

[0127] 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.

[0128] Examples

[0129] The following shows examples (embodiments) considered to be preferable during implementation, but the scope of the present invention is not limited to these embodiments.

[0130] For tires having substantially the same constitution except for the carcass ply and belt layer of each specification shown in Table 1 Figure 1 (tire size: 195 / 65R15) shown in the constitution, research was conducted on the handling stability and low fuel consumption, and the results were calculated based on the evaluation method described later and are shown together in the lower part of Table 1.

[0131] 1. Evaluation of handling stability

[0132] One test driver rides in a vehicle (a domestic FR car with a displacement of 2000 cc) with each test tire installed on all wheels and drives around on a dry asphalt test track at a speed of 100 km / h. And 20 test drivers respectively conduct a sensory evaluation of the handling stability during driving based on characteristics such as steering wheel responsiveness, rigidity feeling, and grip, scoring from 1 to 10 (the larger the value, the better), and calculate the total score thereof.

[0133] Next, taking the result in Comparative Example 1 as 100, it is exponentiated based on the following formula as the evaluation of handling stability. The larger the value, the more excellent the handling stability.

[0134] Handling stability evaluation = [(result of test tire) / (result of Comparative Example 1)] × 100

[0135] 2. Evaluation of low fuel consumption

[0136] Using a rolling resistance testing machine, the rolling resistance coefficient RRC (Rolling Resistance Coefficient) of each test tire when driving on a drum at a speed of 80 km / h under the following conditions is measured as an index for evaluating low fuel consumption.

[0137] Rim used: 15×6J

[0138] Internal pressure: 210 kPa

[0139] Load: 4.35 kN

[0140] Next, taking the result in Comparative Example 1 as 100, it is exponentiated based on the following formula as the evaluation of low fuel consumption. The larger the value, the more excellent the low fuel consumption.

[0141] Low fuel consumption evaluation = [(result of Comparative Example 1) / (result of test tire)] × 100

[0142] The comprehensive performance is represented by the sum of the indices of the handling stability evaluation and the low fuel consumption evaluation obtained above.

[0143] [Table 1]

[0144]

[0145] 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 changes can be made to the above embodiments within the same and equivalent scope as the present invention.

[0146] The present invention (1) relates to a tire having a carcass part and a belt layer part, and is characterized in that

[0147] The carcass ply constituting the above carcass part is a carcass ply formed using carcass ply cords with a linear density exceeding 4400 dtex.

[0148] The above belt part is formed by overlapping at least two or more layers of belts, and the belt uses steel cord composed of one filament as the belt ply cord.

[0149] Furthermore, the diameter Pr (mm) of the above ply cord, the diameter Br (mm) of the above belt ply cord, and the radial tire distance Bg (mm) between the belt ply cords in the adjacent above belts satisfy the following formula.

[0150] (Br + Bg) / Pr ≤ 1.00

[0151] The tire according to the present invention (2) as described in the present invention (1), wherein the above carcass part is composed of one carcass ply.

[0152] The tire according to the present invention (3) as described in the present invention (1), wherein the cord diameter of the above belt ply cord is 0.29 mm or more and 0.42 mm or less.

[0153] The tire according to the present invention (4) as described in the present invention (1), wherein the number of cords E CA (per root) in the tire width direction of every 50 mm width of the above carcass part and the number of cords E BE (per root) in the tire width direction of every 50 mm width of the above belt part satisfy the following formula.

[0154] |E CA - E BE | ≤ 15

[0155] The tire according to the present invention (5) as described in the present invention (1), wherein the number of cords E BE (per root) in the tire width direction of every 50 mm width of the above belt part is 45 or less.

[0156] The tire according to the present invention (6) as described in the present invention (1), wherein the sum of the intermediate elongation rate (%) and the heat shrinkage rate (%) of the above ply cord is less than 8.3.

[0157] Symbol Explanation

[0158] 1 Tire

[0159] 2 Tread

[0160] 3 Sidewall

[0161] 4 Bead

[0162] 5 Bead core

[0163] 6 carcass part

[0164] 6A carcass ply

[0165] 6a inner main part

[0166] 6b outer folded-back part

[0167] 7 belt layer part

[0168] 7A first belt layer

[0169] 7B second belt layer

[0170] 8 bead filler

[0171] C center line

Claims

1. A tire comprising a carcass portion and a belt portion, characterized in that: The carcass ply constituting the carcass portion is a carcass ply formed using ply cords having a linear density exceeding 4400 dtex. The belt layer portion is formed by overlapping at least two belt layers, and the belt layer uses a steel cord composed of a single filament as a belt layer cord. Furthermore, the diameter Pr of the carcass cord, the diameter Br of the belt cord, and the tire radial distance Bg between the belt cords in adjacent belt layers satisfy the following formula: (Br+Bg) / Pr≤1.00 The units of the diameter Pr, the diameter Br and the distance Bg are mm.

2. The tire according to claim 1, characterized in that The carcass portion is composed of one carcass ply layer.

3. The tire according to claim 1, characterized in that The belt cords have a cord diameter of 0.29 mm or more and 0.42 mm or less.

4. The tire according to claim 1, characterized in that The number of cords E per 50 mm width in the tire width direction of the carcass CA and the number of cords E per 50 mm width in the tire width direction of the belt layer BE Satisfies the following formula, |And CA -AND BE |≤15 Among them, the number of cords E CA and the number of cords E BE The unit of is the root.

5. The tire according to claim 1, characterized in that The number of cords E per 50 mm width in the tire width direction of the belt layer portion BE is less than 45, wherein the cord number E BE The unit of is the root.

6. The tire according to claim 1, characterized in that The sum of the intermediate elongation and thermal shrinkage of the ply cords is less than 8.3, wherein the units of the intermediate elongation and thermal shrinkage of the ply cords are %.

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