tire

Abstract

To further improve durability.SOLUTION: A tire comprises: a carcass comprising a carcass cord; a belt which comprises a belt cord and is provided outside the carcass in a tire radial direction; a band which comprises a band cord comprising a polyester fiber and is provided outside the belt in the tire radial direction; and a tread provided outside the band in the tire radial direction. The belt cord is a cord comprising one filament. A diameter (mm) of the band cord and a diameter (mm) of the belt cord satisfy the following expression: |the diameter of the band cord-the diameter of the belt cord |<0.40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 describes a pneumatic tire that includes a carcass, a belt, and a band. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-239069 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to further improve durability. [Means for solving the problem]

[0005] The present invention provides a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; a band provided on the outer side of the belt in the tire radial direction, the band having a band cord including polyester fibers; A tire comprising a tread provided on the outer side of the band in the tire radial direction, The belt cord is a cord composed of one filament, The diameter (mm) of the band cord and the diameter (mm) of the belt cord are expressed by the following formula: (1) Satisfied Along with Number of cords per 50 mm width of the band cord E BA and the number of cords E per 50 mm width of the belt cord BE and satisfy the following formula (2): A tire characterized by: |Band cord diameter - Belt cord diameter| <0.40 (1) |E BA -E BE |<30 (2) [Effects of the Invention]

[0006] According to the present invention, it is possible to further improve durability. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view illustrating the structure of an example of a tire according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram illustrating measurement of bending rigidity. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] 1. Overview The tire according to the present invention comprises a carcass having a carcass cord, a belt having a belt cord and provided radially outward of the carcass, a band having a band cord containing polyester fiber and provided radially outward of the belt, and a tread provided radially outward of the band. The belt cord is a cord composed of a single filament. The diameter (mm) of the band cord and the diameter (mm) of the belt cord are determined by the following formula: (1) Satisfied In addition, the number of cords per 50 mm of band cord width E BA and the number of cords per 50 mm of belt cord width E BE This means that the following formula (2) is satisfied. . |Band cord diameter - Belt cord diameter| <0.40 (1) |E BA -EBE |<30 (2)

[0010] These characteristics make it possible to further improve durability, as will be described later.

[0011] In the above, the "cord diameter" in the band cord diameter and belt cord diameter refers to the diameter when the circumscribing circle of the cross section perpendicular to the extension direction of the cord is a perfect circle, and refers to the equivalent circle diameter (the diameter of a perfect circle when the cross-sectional area is the same as that of the ellipse) when the circumscribing circle is an ellipse or the like.

[0012] 2. Mechanism of effect manifestation in the tire according to the present invention The mechanism by which the above-described effects of the tire according to the present invention are exhibited is believed to be as follows.

[0013] In the tire according to the present invention, the belt cord is made up of a single filament, and the difference between the diameter (mm) of the band cord and the diameter (mm) of the belt cord is small, specifically, |Band cord diameter-Belt cord diameter|<0.40. This makes it possible to reduce the diameter of the belt cord, thin the thickness (rubber gauge) of the rubber topped on the belt cord, and reduce the difference between the stress of the band and the stress of the belt, which is thought to sufficiently suppress looseness between the band and the belt and improve durability.

[0014] It is more preferable that |diameter of band cord−diameter of belt cord| is 0.30 or less, even more preferably 0.20 or less, and even more preferably 0.10 or less.

[0015] [2] More preferred embodiments of the tire according to the present invention The tire according to the present invention can achieve even greater effects by adopting the following aspects.

[0016] 1. Ends of band cords and belt cords In the present invention, the ends E of the band cord BA and Ends E of the belt cord BE It is preferable that the difference between the stress of the band and the stress of the belt is small, which can further reduce the difference between the stress of the band and the stress of the belt, thereby further suppressing looseness between the band and the belt and further improving durability.In this specification, "ends" means "the number of cords per 50 mm width in the tire width direction."

[0017] Specifically, |E BA -E BE It is believed that durability can be further improved if |E < 30. BA -E BE is more preferably 15 or less, and particularly preferably 0. 2. Belt cord bending rigidity In the present invention, it is preferable that the bending rigidity of the belt cord is small, which makes the belt cord more flexible and reduces the stress difference with the band cord, thereby enabling further improvement in durability.

[0018] Specifically, it is believed that durability can be further improved when the viscosity is less than 40 (g·cm), more preferably 30 (g·cm) or less, and even more preferably 20 (g·cm) or less.

[0019] The bending stiffness of the belt cord can be measured using, for example, a stiffness tester (e.g., Model 150-D) manufactured by Taber (USA) according to the following procedure. First, both ends of a 145 mm long belt cord are attached to the clamps of the stiffness tester, and the belt cord 10 is bent at angles of +15 degrees and -15 degrees as shown in Figure 2. The average value of the bending moment at +15 degrees and the bending moment at -15 degrees is defined as the bending stiffness value (g·cm).

[0020] 3. Intermediate elongation and heat shrinkage rate of band cord In the present invention, it is preferable that the band cord has both a low intermediate elongation and a low heat shrinkage rate. This improves dimensional stability and makes the cord less likely to stretch, bringing the cord closer to the hardness of the belt, which is thought to further suppress looseness between the band and the belt and further improve durability.

[0021] Specifically, it is believed that durability can be further improved when the sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the band cord is less than 15. A value of 10 or less is more preferable.

[0022] The intermediate elongation (%) of the band cord can be determined from the elongation (%) at a load of 44 N in the "load-elongation" curve of the band cord obtained in a room temperature environment (25°C ± 2°C) in accordance with "JIS L1017:2002 Testing methods for synthetic fiber tire cords."

[0023] The heat shrinkage rate (%) of the band cord can be determined in accordance with "JIS L1017:2002 Testing methods for synthetic fiber tire cords" from the ratio y / x (%) of the amount of shrinkage y (mm) to the length x (mm) of the band cord before leaving it at 180°C for 30 minutes without load.

[0024] The band may be one layer or two layers. The band may be formed across the entire width of the tread, or may be formed only at both ends of the tread. The band cord may be made of fiber. The fiber constituting the band cord may be polyester fiber, preferably PET (polyethylene terephthalate) fiber or PEN (polyethylene naphthalate) fiber, and more preferably PET fiber. The fiber constituting the band cord may be fiber recycled from used or waste products, or fiber synthesized from biomass.

[0025] 4. Use of sustainable materials In the tire according to the present invention, the belt, band, and carcass ply described above are produced by coating both sides of the cord arrangement body with a conventionally known rubber composition, respectively. However, in consideration of the strong demand for environmental protection in recent years, it is preferable to replace the materials constituting these rubber compositions with sustainable materials.

[0026] (1) Rubber materials For example, instead of using petroleum-derived raw materials (monomers) for synthetic rubbers such as SBR and BR, it is possible to use those recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0027] Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples thereof include recycled butadiene and recycled aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene, and examples of aromatic vinyls include, but are not particularly limited to, styrene. Among these, it is preferable to use recycled butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) as raw materials.

[0028] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0029] Furthermore, the raw materials (monomers) of synthetic rubbers such as SBR and BR may be derived from biomass. Examples of biomass-derived monomers (biomass monomers) include, but are not limited to, biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl include, but are not limited to, styrene. Furthermore, methods for producing biomass monomers are also not limited, including, for example, biological and / or chemical and / or physical conversion of animals and plants. A typical example of biological conversion is fermentation using microorganisms, while examples of chemical and / or physical conversion include catalytic, high-temperature, high-pressure, electromagnetic, critical fluid, and combinations thereof. Biomass sources for these monomers include sugar, wood, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0030] The polymer synthesized from a biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0031] Whether or not the raw material of a polymer is derived from biomass can be determined by pMC (percent modern carbon) measured in accordance with ASTM D6866-10.

[0032] pMC is the modern standard reference carbon 14 of sample against C concentration 14 This is the ratio of the carbon concentration, and this value is used as an index showing the biomass ratio of the compound (rubber). The significance of this value is explained below.

[0033] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14 C exists. 14 C is called a radioactive isotope, and its half-life is 5,730 years, and it decreases regularly. It takes 226,000 years for all of it to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when it was first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C element.

[0034] on the other hand, 14 C is produced continuously by nuclear reactions in the atmosphere caused by cosmic rays, and this balances with the decrease due to radioactive decay. In the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol%. Therefore, by using the difference between these values, it is possible to calculate the ratio (biomass ratio) of compounds derived from natural resources (compounds derived from biomass resources) in a certain compound (rubber).

[0035] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12 C) is measured. 14The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14 The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0036] Therefore, if rubber is made from 100% biomass (natural) derived materials, it will show a value of approximately 110 pMC, although there may be regional differences (currently, under normal conditions, it is often not 100). On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will be approximately 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0037] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0038] It is also preferable to use vulcanized rubber particles as the rubber material.

[0039] The vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used alone or in combination of two or more types.

[0040] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0041] As commercially available vulcanized rubber particles, for example, products from Lehigh Corporation, Muraoka Rubber Industries Co., Ltd., etc. can be used.

[0042] (2) Silica Rubber compositions generally contain silica as a reinforcing filler, but it is also preferable to use sustainable silica instead of mineral-derived raw materials such as quartz.

[0043] The silica is not particularly limited, and can be, for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrated silica), or other silica commonly used in the tire industry. The raw material for silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from silica-containing products. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. These silicas can be used alone or in combination of two or more types.

[0044] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0045] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0046] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silica in rice husk ash (see, for example, JP 2009-2594 A and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222).

[0047] Amorphous silica extracted from rice husks may be commercially available from Wilmar Co., Ltd., etc.

[0048] (3) Carbon black It is also common for rubber compositions to contain carbon black as a reinforcing filler, and it is also preferable to use sustainable carbon black as such carbon black.

[0049] Carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by pyrolysis of methane, such as in a thermal black process. Commercially available carbon black products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Co., Ltd. These carbon blacks may be used alone or in combination.

[0050] (4) Oil Examples of oils commonly used as softeners include process oil, vegetable oil, and animal oil. Examples of process oil include paraffinic process oil (mineral oil), naphthenic process oil, and aromatic process oil. Specific examples of process oil include mild extract solvated (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, as an environmental measure, process oil with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of such low-PCA process oil include MES, TDAE, and heavy naphthenic oil. Furthermore, from the perspective of life cycle assessment, refined waste oil from rubber mixers and engines, or waste cooking oil from restaurants, may also be used.

[0051] Specific examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above-mentioned oils, interesterified oils obtained by interesterifying the above-mentioned oils, hardened oils obtained by hydrogenating the above-mentioned oils, thermally polymerized oils obtained by thermally polymerizing the above-mentioned oils, oxidatively polymerized oils obtained by oxidizing the above-mentioned oils, and waste edible oils recovered from edible oils. Vegetable oils may be liquid or solid at room temperature (25°C). These vegetable oils may be used alone or in combination of two or more.

[0052] The vegetable oil preferably contains acylglycerol, and more preferably triacylglycerol. Here, acylglycerol refers to a compound in which a hydroxyl group of glycerin is ester-bonded to a fatty acid. The acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. Furthermore, the acylglycerol may be liquid or solid at room temperature (25°C).

[0053] The method for confirming whether or not the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, the rubber composition is immersed in deuterated chloroform at room temperature. 1 When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0054] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0055] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0056] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0057] (5) Softeners other than oil In addition to the oils described above, the rubber composition may also contain softeners that are liquid (liquid state) at room temperature (25°C) or solid at room temperature (25°C) as softeners that impart plasticity to the rubber component. Examples of such softeners include resin components, liquid polymers, and ester-based plasticizers. These softeners may be derived from petroleum, biomass, or naphtha recycled from rubber or non-rubber products (sustainable softeners). Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as softeners. These softeners may be used alone or in combination.

[0058] (6) Wax Rubber compositions generally contain wax, but the wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include petroleum-based waxes, mineral-based waxes, synthetic waxes, and plant-derived waxes. Of these, petroleum-based waxes and plant-derived waxes are preferred, with petroleum-based waxes being more preferred. Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of petroleum-based waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. Waxes that can be used include those commercially available from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Paramelt Co., Ltd. These waxes may be used alone or in combination of two or more.

[0059] (7) Antiaging agents Rubber compositions generally contain antioxidants. The antioxidants are not particularly limited, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DP ... Examples of antiaging agents include p-phenylenediamine-based antioxidants such as tolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, etc.

[0060] In the rubber composition, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. The compound of the present invention can be obtained from carbon dioxide by directly converting carbon dioxide, or by converting methane obtained through a methanation process in which methane is synthesized from carbon dioxide.

[0061] [3] Implementation form The present invention will be specifically described below based on embodiments.

[0062] 1. Tire according to this embodiment FIG. 1 is a schematic cross-sectional view illustrating the structure of an example of a tire according to the present embodiment, showing a tire meridian cross-section including the rotation axis of the tire in a normal state.

[0063] Here, "normal condition" refers to a state in which the tire is mounted on a normal rim, is inflated to a normal internal pressure, and is not under load.

[0064] "Genuine rim" refers to the rim specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA Year Book." For ETRTO (The European Tire and Rim Technical Organization), it refers to the "Measuring Rim" listed in the "Standards Manual." For TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "Year Book." JATMA, ETRTO, and TRA are referenced in that order, and if an applicable size is available at the time of reference, that standard is followed. For tires not specified in the standard, it refers to the rim that can be mounted on the rim and can maintain internal pressure, i.e., the rim with the smallest rim diameter and the next narrowest rim width, among rims that do not leak air between the rim and tire.

[0065] "Normal internal pressure" refers to the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, it refers to "Maximum Air Pressure," for ETRTO, it refers to "INFLATION PRESSURE," and for TRA, it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." Refer to JATMA, ETRTO, and TRA in that order, and follow the standard if there is an applicable size at the time of reference. In the case of a tire not specified in the standard, it refers to the normal internal pressure (250 KPa or higher) of another tire size (specified in the standard) that is specified using the normal rim as the standard rim. Note that if multiple normal internal pressures of 250 KPa or higher are listed, it refers to the smallest value among them.

[0066] As shown in Fig. 1, a tire 1 includes a tread 2, a sidewall 3, a bead 4, a carcass 6, and a belt 7. Note that C denotes a centerline. In Fig. 1, the band disposed between the carcass and the tread is omitted.

[0067] (1) Carcass The carcass 6 is made up of one carcass ply 6A, which is secured by passing from the tread 2 through the sidewall 3 and around the bead core 5 of the bead 4 from the inside to the outside (1-0 structure). The carcass 6 may be made up of two carcass plies. The carcass cord may be made of a conventionally known material, such as polyester fibers such as PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers, polyamide fibers such as nylon 6 fibers and nylon 66 fibers, and aramid fibers. The fibers constituting the carcass cord may be fibers recycled from used or waste products, or fibers synthesized from biomass.

[0068] In FIG. 1, 6a denotes the inner main body portion of the carcass ply 6A, 6b denotes the outer folded portion, and between the inner main body portion 6a and the outer folded portion 6b, for example, a bead apex rubber 8 extending radially outward from the bead core 5 is arranged.

[0069] The carcass ply 6A is constructed by topping a predetermined rubber composition for carcass ply on both sides of a cord arrangement body in which ply cords of a predetermined linear density are arranged in a predetermined number of ends (not shown).

[0070] In the present invention, the ply cords are made of polyester synthetic fibers having a high modulus.

[0071] (2) Belt The belt 7 is disposed radially outside the carcass 6 and inside the tread 2 .

[0072] The belt 7 is made up of one or more belt plies (it may be one, two, or three or more), and in Fig. 1, it is made up of a first belt ply 7A located on the inner side in the tire radial direction and a second belt ply 7B located on the outer side of the first belt ply 7A. Note that three or more belt plies may also be used.

[0073] The belt ply is made thinner than the carcass ply (not shown) by topping both sides of a cord arrangement in which cords (belt cords) each consisting of a single filament are arranged in a predetermined number of ends with a predetermined rubber composition for a belt. The filaments constituting the belt cords are preferably made of metal, more preferably iron, particularly steel. The cross-sectional shape of the filaments is preferably circular, but may also be elliptical. The filaments may be corrugated or plated. In this embodiment, the filaments having a circular cross-sectional shape are used without being corrugated or twisted.

[0074] It is believed that by employing such a belt 7, durability can be improved.

[0075] 2. Tire manufacturing The tire according to the present embodiment can be manufactured by a conventional method.

[0076] Specifically, an inner liner as a component for ensuring the airtightness of the tire, a carcass as a component for withstanding the load, impact, and inflation pressure to which the tire is subjected, and a belt as a component for tightly fastening the carcass and increasing the rigidity of the tread are wound around a forming drum, and both ends of the carcass ply are fixed to both side edges, and beads as components for fixing the tire to the rim are placed. After forming into a toroidal shape, a tread is attached to the center of the outer periphery and sidewalls are attached to the radially outer sides to form the side portions, thereby producing an unvulcanized tire.

[0077] The unvulcanized tire thus prepared is then heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by using a known vulcanization method. The vulcanization temperature is, for example, greater than 120°C and less than 200°C, and the vulcanization time is, for example, greater than 5 minutes and less than 15 minutes.

[0078] As described above, the tire obtained as described above has the belt and band properly formed, and therefore, durability can be further improved.

[0079] The tire according to the present invention can be suitably used as a tire for passenger cars, a tire for large passenger cars, a tire for large SUVs, a tire for small trucks, and the like. [Example]

[0080] Examples (embodiments) that are considered preferable for carrying out the present invention will be shown below, but the scope of the present invention is not limited to these examples.

[0081] Except for the belts and bands of each specification shown in Table 1, tires that are essentially identical were examined with the configuration shown in Figure 1 (tire size: 195 / 65R15). The results of calculations based on the evaluation method for durability and fuel economy described below are also shown at the bottom of Table 1.

[0082] 1. Durability evaluation Each test tire is mounted on a rim (size = 15 x 6J), and the tire is inflated with air to adjust the internal pressure to 230 kPa. Then, the tire is attached to a drum running test machine, a vertical load of 5.88 kN is applied, and the speed is increased in steps of 10 km / h from 210 km / h, and the time until the tire is damaged is measured.

[0083] Next, the results of Comparative Example 1 were set to 100 and indexed according to the following formula to evaluate durability. A larger value indicates a longer time until damage occurs and superior durability after high-speed running. Durability evaluation = [(Test tire results) / (Comparative example 1 results)] x 100

[0084] 2. Fuel efficiency evaluation Using a rolling resistance tester, the rolling resistance coefficient (RRC) of each test tire is measured when the tire runs on a drum at a speed of 80 km / h under the following conditions. Rim used: 15x6J Internal pressure: 210kPa Load: 4.35kN

[0085] Next, the result of Comparative Example 1 was set as 100, and the result was indexed based on the following formula to evaluate fuel economy. A larger value indicates better fuel economy. Fuel economy evaluation=[(Result of Comparative Example 1) / (Result of test tire)]×100

[0086] 3. Overall performance Overall performance is expressed as the sum of the durability and fuel efficiency indices.

[0087] [Table 1]

[0088] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiments within the scope of the same or equivalent to the present invention.

[0089] The present invention (1) is a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; a band provided on the outer side of the belt in the tire radial direction, the band having a band cord including polyester fibers; A tire comprising a tread provided on the outer side of the band in the tire radial direction, The belt cord is a cord composed of one filament, The diameter (mm) of the band cord and the diameter (mm) of the belt cord are expressed by the following formula: (1) Satisfied Along with Number of cords per 50 mm width of the band cord E BA and the number of cords E per 50 mm width of the belt cord BE This means that the following formula (2) is satisfied. The tire is characterized by the above. |Band cord diameter - Belt cord diameter| <0.40 (1) |E BA -E BE |<30 (2)

[0090] The present invention (2) is In the formula (1), (|diameter of band cord−diameter of belt cord|) is 0.2 or more. The tire according to the present invention (1) is characterized by: 。

[0091] The present invention (3) is The tire according to the present invention (1) is characterized in that the bending rigidity of the belt cord is less than 40 (g·cm).

[0092] The present invention (4) is The tire according to the present invention (1) is characterized in that the sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the band cord is less than 15. [Explanation of symbols]

[0093] 1 tire 2 Tread 3 Sidewall 4 beads 5 bead core 6. Carcass 6A carcass ply 6a Inner body part 6b Outer folded part 7 Belt 7A First Belt Ply 7B 2nd belt ply 8 Bead apex rubber 10 Band cord C Center line

Claims

1. a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; a band provided on the outer side of the belt in the tire radial direction, the band having a band cord including polyester fibers; A tire comprising a tread provided on the outer side of the band in the tire radial direction, The belt cord is a cord composed of one filament, The diameter (mm) of the band cord and the diameter (mm) of the belt cord satisfy the following formula (1), The tire is characterized in that the number of cords E BA per 50 mm width of the band cord and the number of cords E BE per 50 mm width of the belt cord satisfy the following formula (2): |Band cord diameter - Belt cord diameter| < 0.40 (1) |E BA -E BE |<30 (2)

2. A tire as described in claim 1, characterized in that (|diameter of band cord - diameter of belt cord|) in the formula (1) is 0.2 or more.

3. 2. The tire according to claim 1, wherein the belt cord has a bending rigidity of less than 40 (g·cm).

4. 2. The tire according to claim 1, wherein the sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the band cord is less than 15.

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