Tire

Abstract

The invention provides a tire which further improves durability. A tire is provided with: a carcass provided with carcass cords; a belt layer provided with belt layer cords and provided on the outside of the carcass in the tire radial direction; a cap ply provided with cap ply cords including polyester fibers and provided on the outside of the belt layer in the tire radial direction; and a tread provided on the outside of the cap ply in the radial direction of the tire, in which the belt cord is a cord comprising four filaments, and the diameter (mm) of the cap ply cord and the diameter (mm) of the belt cord satisfy the following formula. The diameter of the cap ply cords-the diameter lt of the belt cords; and 0.40.

Description

Technical Field

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

[0002] Patent Document 1 describes a pneumatic tire including 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 further improve durability.

[0008] Means for Solving the Problems

[0009] The present invention relates to a tire including:

[0010] a carcass including carcass cords;

[0011] a belt layer including belt cords and disposed radially outside the carcass of the tire;

[0012] a chafer layer including chafer cords containing polyester fibers and disposed radially outside the belt layer of the tire; and

[0013] a tread disposed radially outside the chafer layer of the tire,

[0014] wherein the tire is characterized in that

[0015] the belt cords are cords composed of 4 filaments,

[0016] the diameter (mm) of the chafer cords and the diameter (mm) of the belt cords satisfy the following formula.

[0017] |diameter of chafer cords - diameter of belt cords| < 0.40

[0018] Effects of the Invention

[0019] According to the present invention, further improvement in durability can be achieved. Brief Description of the Drawings

[0020] Figure 1 is a schematic cross-sectional view showing the structure of a tire according to an embodiment of the present invention.

[0021] Figure 2 is a schematic view for explaining the measurement of bending rigidity. Detailed implementation mode

[0022] [1] Features of the tire of the present invention

[0023] First, the features of the tire of the present invention will be described.

[0024] 1. Outline

[0025] The tire of the present invention includes: a carcass having carcass cords; a belt layer having belt cords and disposed on the radially outer side of the carcass in the tire; a chafer layer having chafer cords containing polyester fibers and disposed on the radially outer side of the belt layer in the tire; and a tread disposed on the radially outer side of the chafer layer in the tire. Further, the belt cords are cords composed of 4 filaments. In addition, the diameter (mm) of the chafer cords and the diameter (mm) of the belt cords satisfy the following formula.

[0026] |Diameter of chafer cord - Diameter of belt cord| < 0.40

[0027] By having these features, as described later, further improvement in the durability of the tire can be achieved.

[0028] It should be noted that in the above, regarding the "diameter of the cord" in the diameter of the chafer cord and the diameter of the belt cord, when the circumscribed circle of the cross-section perpendicular to the extending direction of the cord is a perfect circle, it refers to the diameter, and when it is an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the circle when assuming the same cross-sectional area).

[0029] 2. Mechanism of effect manifestation in the tire of the present invention

[0030] Regarding the mechanism of the above effect manifestation in the tire of the present invention, the following can be considered.

[0031] In the tire of the present invention, the belt cords are composed of 4 filaments. Thereby, it is possible to reduce the cord diameter while maintaining the strength, and thus it is considered that the thickness of the rubber (rubber thickness) adhered to the belt cords can be reduced, achieving further improvement in the durability of the tire.

[0032] In addition, by reducing the difference between the diameter (mm) of the chafer cord and the diameter (mm) of the belt cord, specifically, setting |Diameter of chafer cord - Diameter of belt cord| < 0.40, it is possible to reduce the difference in stress between the chafer layer and the belt layer, and thus it is considered that loosening between the chafer layer and the belt layer can be sufficiently suppressed, achieving improvement in durability.

[0033] It should be noted that |Diameter of chafer cord - Diameter of belt cord| is more preferably 0.30 or less, and further preferably 0.20 or less.

[0034] [2]More preferred embodiments of the tire of the present invention

[0035] The tire of the present invention can achieve greater effects by adopting the following methods.

[0036] 1. Density of the cap ply cords and belt ply cords

[0037] In the present invention, the density E of the cap ply cords BA and the density E of the belt ply cords BE preferably have a small difference, whereby the difference between the stress of the above-mentioned cap ply and the stress of the belt ply can be further reduced. Therefore, it is considered that the loosening between the cap ply and the belt ply can be further suppressed, and the durability can be further improved. It should be noted that in this specification, "density" refers to "the number of cords per 50 mm width in the tire width direction".

[0038] Specifically, if |E BA −E BE |<30, it is considered that the durability can be further improved. It should be noted that |E BA −E BE | is more preferably 15 or less, and particularly preferably 0.

[0039] 2. Bending rigidity of the belt ply cords

[0040] In the present invention, the bending rigidity of the belt ply cords is preferably small, whereby the belt ply cords become softer, and the stress difference from the cap ply cords becomes smaller. Therefore, it is considered that the durability can be further improved.

[0041] Specifically, if it is less than 50 (g·cm), it is considered that the durability can be further improved. More preferably, it is 40 (g·cm) or less, and further preferably 20 (g·cm) or less.

[0042] It should be noted that the bending rigidity of the above-mentioned belt ply cords can be measured, for example, using a rigidity testing machine (such as model 150-D) manufactured by TABER Company (USA) according to the following steps. First, both ends of a 145 mm long belt ply cord are installed on the chucks of the rigidity testing machine, as Figure 2 shown, and a bending angle of +15 degrees and -15 degrees is given to the belt ply cord 10. And, the average value of the bending moment at +15 degrees and the bending moment at -15 degrees is defined as the bending rigidity value (g·cm).

[0043] 3. Intermediate elongation and thermal shrinkage of the cap ply cords

[0044] In the present invention, the cords of the crown ply preferably have both a low intermediate elongation rate and a low heat shrinkage rate. Thereby, the dimensional stability is further improved, elongation is difficult, and the hardness is close to that of the belt layer. Therefore, it is considered that loosening between the crown ply and the belt layer can be further suppressed, and further improvement in durability can be achieved.

[0045] Specifically, if the sum of the intermediate elongation rate (%) and the heat shrinkage rate (%) of the cords of the crown ply is less than 15, it is considered that further improvement in durability can be achieved. More preferably, it is 10 or less.

[0046] It should be noted that the intermediate elongation rate (%) of the cords of the crown ply can be obtained from the elongation rate (%) at a load of 44 N in the "load-elongation" curve of the cords of the crown ply obtained in an environment at room temperature (25°C ± 2°C) according to "JIS L1017:2002 Test Methods for Chemical Fibre Tyre Cords".

[0047] In addition, the heat shrinkage rate (%) of the cords of the crown ply can be obtained from the ratio y / x (%) of the shrinkage amount y (mm) to the length x (mm) of the cords of the crown ply before placement when the cords of the crown ply are placed for 30 minutes at a temperature of 180°C in a load-free state according to "JIS L1017:2002 Test Methods for Chemical Fibre Tyre Cords".

[0048] The crown ply can be 1 layer or 2 layers. In addition, the crown ply can be formed in the entire width direction of the tread, or can be formed only at both end portions of the tread. The cords of the crown ply can be composed of fibers. As the fibers constituting the cords of the crown ply, polyester fibers can be used, preferably PET (polyethylene terephthalate) fibers, PEN (polyethylene naphthalate) fibers, and more preferably PET fibers. In addition, the fibers constituting the cords of the crown ply can be fibers recycled from used products or waste products, or can be fibers synthesized from biomass.

[0049] 4. Use of Sustainable Materials

[0050] In the tire of the present invention, the above-mentioned belt layer, carcass ply, and crown ply are produced by covering both sides of the cord arrangement body with a conventionally known rubber composition. However, in consideration of the strong requirements for environmental protection in recent years, it is preferable to replace the materials constituting these rubber compositions with sustainable materials.

[0051] (1) Rubber Material

[0052] For example, the raw materials (monomers) of synthetic rubbers such as 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 petroleum sources.

[0053] 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.

[0054] As a 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 a 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, or decomposed by microwaves, or extracted after mechanical pulverization.

[0055] 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 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.

[0056] 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.

[0057] 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.

[0058] pMC refers to that of the sample14 The ratio of the concentration of 14 C to the concentration of

[0059] C 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. 23 Out of 1 mole (6.02×10 11 atoms) of carbon atoms, there are approximately one trillionth, i.e., about 6.02×10 14 atoms of 14 C. 14 C is called a radioactive isotope with a half-life of 5730 years and decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere, etc. is taken in and immobilized by plants, etc., 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 time of immobilization 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

[0060] 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 concentration of -12 C in substances from biomass resources that are recycled in the current environment is about 1×10

[0061] mol% relative to the total C atoms as described above. Therefore, by using the difference between these values, the proportion (biomass ratio) of the compound from natural resources (compound from biomass resources) in a certain compound (rubber) can be calculated. 14 This 13 C is usually measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, the concentration of 13 C ( 12 C / 14 C) and the concentration of 14 C ( 12 C / 14 C) are measured. In the measurement, the concentration of 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 per 1 g of carbon) is separated into each carbon isotope, and for 13 C, it is corrected to a certain value, and decay correction is carried out from 1950 AD to the measurement date, and 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.

[0062] Therefore, if rubber is made from a substance that is 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 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%.

[0063] 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.

[0064] In addition, as the rubber material, vulcanized rubber particles are also preferably used.

[0065] 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.

[0066] As the vulcanized rubber particles, there is no particular limitation, and they can be non-modified vulcanized rubber particles or modified vulcanized rubber particles.

[0067] As commercially available products of vulcanized rubber particles, products of, for example, Lehigh Company, Murakami Rubber Industry Co., Ltd. can be used.

[0068] (2) Silica

[0069] The rubber composition usually contains silica as a reinforcing filler, but it is also preferred to use sustainable silica instead of raw materials from minerals such as quartz.

[0070] 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 derived from minerals such as quartz, or a raw material derived from biological sources such as rice husks (for example, silica based on biomass materials such as rice husks), 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 the wet method is preferred. These silicas can be used alone or in combination of two or more.

[0071] Silica based on biomass materials can be obtained, for example, as follows: Silicate is extracted from rice husk ash obtained by burning rice husks 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.

[0072] 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, 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.

[0073] 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 Internet Journal B / 2019, vol. 6, p. 216-222, etc.).

[0074] Amorphous silica extracted from rice husks can use commercially available amorphous silica such as that from Wilmar Corporation.

[0075] (3) Carbon black

[0076] 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.

[0077] 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), or can 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.

[0078] (4) Oil

[0079] As the oil generally used as a softening agent, examples thereof include processing oil, vegetable oil, animal oil, etc. As the processing oil, examples thereof 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 compound (PCA) can also be used. As the above-mentioned low-PCA-content processing oil, examples thereof 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.

[0080] And, 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. 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, oxidation-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). These vegetable oils can be used alone or in combination of two or more.

[0081] 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 oxidation polymerization, etc. In addition, acylglycerol can be liquid or solid at normal temperature (25°C).

[0082] 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 blended 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] (5) Softeners other than oil

[0087] 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.

[0088] (6) Wax

[0089] 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.

[0090] (7) Anti-aging agents

[0091] An antioxidant is usually contained in the rubber composition. There is no particular limitation on the antioxidant, 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; p-phenylenediamine-based antioxidants 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 antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol-based, triphenol-based, and polyphenol-based antioxidants such as tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants 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., etc. can be used.

[0092] It should be noted that in the rubber composition, various materials containing carbon atoms (such as rubber, oil, resin, vulcanization accelerator, antioxidant, 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 of synthesizing methane via carbon dioxide can be converted.

[0093] [3] Embodiment

[0094] Hereinafter, the present invention will be specifically described based on the embodiment.

[0095] 1. Tire of the present embodiment

[0096] Figure 1 It is a schematic cross-sectional view showing the structure in an example of the tire of the present embodiment, and shows a tire meridian cross-section including the rotation axis in the normal state of the tire.

[0097] 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.

[0098] 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 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 is an applicable size 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.

[0099] 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 is an applicable size 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 where there are multiple regular internal pressures above 250 KPa, it refers to the minimum value among them.

[0100] As Figure 1 shown, the tire 1 includes a tread 2, a sidewall 3, a bead 4, a carcass 6, and a belt layer 7. It should be noted that C is the center line. Moreover, Figure 1 the description of the chafer layer disposed between the carcass and the tread is omitted.

[0101] (1) Carcass

[0102] The carcass 6 is composed of one carcass ply 6A, and is locked by being folded back from the inside to the outside through the carcass bead core 5 that goes from the tread 2, around the sidewall 3, to the bead 4 (1-0 structure). The carcass 6 may also be composed of two carcass plies. In addition, as the material of the carcass cords, known materials can be used, such as polyester fibers like PET (polyethylene terephthalate) fibers, PEN (polyethylene naphthalate) fibers, polyamide fibers like nylon 6 fibers, nylon 66 fibers, and aromatic polyamide fibers. The fibers constituting the carcass cords can be recycled fibers from used products or waste products, or can be fibers synthesized from biomass.

[0103] It should be noted that Figure 1 In, 6a is the inner main body part of the carcass ply 6A, and 6b is the outer folded-back part. Between the inner main body part 6a and the outer folded-back part 6b, for example, a bead filler 8 extending radially outward of the tire from the carcass bead core 5 is arranged.

[0104] The carcass ply 6A is formed by applying a rubber composition for carcass ply to both sides of a cord arrangement body in which cords of a specified linear density are arranged at a specified density (not shown).

[0105] It should be noted that in the present invention, polyester synthetic fibers with high modulus are used as the cord of the ply.

[0106] (2) Belt layer

[0107] The belt layer 7 is arranged on the radially outer side of the carcass 6 and inside the tread 2.

[0108] The belt layer 7 is composed of one or more (it can be one, two, or three or more) belt layer plies, Figure 1 In, it is composed of a first belt layer ply 7A located on the radially inner side of the tire and a second belt layer ply 7B located on the outer side of the first belt layer ply 7A. It should be noted that three or more belt layer plies can also be used.

[0109] The belt layer ply is formed by applying a rubber composition for belt layer to both sides of a cord arrangement body in which belt layer cords composed of four filaments (the material is metal, especially iron, and steel is particularly preferred) are arranged at a specified density, and is made into a thickness thinner than that of the carcass ply (not shown). The material of the filaments constituting the belt layer cords is preferably metal, more preferably iron. In addition, its cross-sectional shape is preferably circular, but can also be elliptical. And, it can be corrugated, and can also be plated. In addition, it can be untwisted, can be single-twist (1×4), or can be layer-twist (2+2), and 1×4 structure is preferred. In the present embodiment, the filaments with a circular cross-sectional shape are used without corrugation and in a single-twist (1×4 structure).

[0110] By adopting such a belt layer 7, it is considered that an improvement in durability can be achieved.

[0111] 2. Manufacture of tire

[0112] The tire of the present embodiment can be manufactured by a conventional method.

[0113] Specifically, on a forming drum, an inner liner layer as a component for ensuring the 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 ply at both side edges, a bead as a component for fixing the tire to a rim is arranged. After being formed into a ring shape, by attaching a tread to the central part of the outer periphery and attaching a sidewall to the radially outer side to form a sidewall part, an unvulcanized tire is produced.

[0114] Then, the unvulcanized tire produced above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying a 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.

[0115] In the tire obtained above, as described above, the belt layer and the chafer ply are appropriately formed, so that a further improvement in the durability of the tire can be achieved.

[0116] 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.

[0117] Examples

[0118] The following shows examples (examples) considered to be preferable in implementation, but the scope of the present invention is not limited to these examples.

[0119] Tires that are substantially the same except for the belt layer and chafer ply of each specification shown in Table 1 are studied with the Figure 1 shown configuration (tire size: 195 / 65R15), and calculations are carried out based on the evaluation methods for durability and low fuel consumption described later, and the results are shown together in the lower part of Table 1.

[0120] 1. Durability evaluation

[0121] Each test tire was assembled onto a rim (size = 15×6J), filled with air, and after adjusting the internal pressure to 230 kPa, it was installed on a drum driving test machine. A longitudinal load of 5.88 kN was applied, and the speed was gradually increased in steps of 10 km / h from 210 km / h, and the time until the tire was damaged was measured. The results are expressed as an index with Comparative Example 1 set to 100. The larger the value, the longer the time until damage, indicating more excellent durability after high-speed driving.

[0122] Next, the results in Comparative Example 1 were set to 100, and were exponentiated based on the following formula for durability evaluation. The larger the value, the more excellent the durability.

[0123] Durability evaluation = [(result of the test tire) / (result of Comparative Example 1)] × 100

[0124] 2. Low fuel consumption evaluation

[0125] Using a rolling resistance test machine, for each test tire, the rolling resistance coefficient RRC (Rolling Resistance Coefficient) was measured when driving on a drum at a speed of 80 km / h under the following conditions.

[0126] Rim used: 15×6J

[0127] Internal pressure: 210 kPa

[0128] Load: 4.35 kN

[0129] Next, the results in Comparative Example 1 were set to 100, and were exponentiated based on the following formula for low fuel consumption evaluation. The larger the value, the more excellent the low fuel consumption.

[0130] Low fuel consumption evaluation = [(result of Comparative Example 1) / (result of the test tire)] × 100

[0131] 3. Comprehensive performance

[0132] The comprehensive performance is expressed as the sum of the indices of durability and low fuel consumption.

[0133] [Table 1]

[0134]

[0135] 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 as the present invention.

[0136] The present invention (1) relates to a tire having:

[0137] A carcass including carcass cords;

[0138] A belt layer including belt cords and disposed radially outside the carcass of the tire;

[0139] A crown belt layer including crown belt cords containing polyester fibers and disposed radially outside the belt layer of the tire; and

[0140] A tread disposed radially outside the crown belt layer of the tire,

[0141] The tire is characterized in that

[0142] The belt cords are cords composed of 4 filaments,

[0143] The diameter (mm) of the crown belt cords and the diameter (mm) of the belt cords satisfy the following formula.

[0144] |Diameter of crown belt cords - Diameter of belt cords| < 0.40

[0145] The tire according to the present invention (2) as described in the present invention (1), characterized in that the number of cords E per 50 mm width of the crown belt cords BA and the number of cords E per 50 mm width of the belt cords BE satisfy the following formula.

[0146] |E BA - E BE | < 30

[0147] The tire according to the present invention (3) as described in the present invention (1), characterized in that the bending rigidity of the belt cords is less than 50 (g·cm).

[0148] The tire according to the present invention (4) as described in the present invention (1), characterized in that the sum of the intermediate elongation rate (%) and the heat shrinkage rate (%) of the crown belt cords is less than 15.

[0149] Symbol description

[0150] 1 Tire

[0151] 2 Tread

[0152] 3 Sidewall

[0153] 4 Bead

[0154] 5 Bead core

[0155] 6 Carcass

[0156] 6A Carcass ply

[0157] 6a Inner main body

[0158] 6b outer folded-back part

[0159] 7 belt layer

[0160] 7A first belt layer cord fabric

[0161] 7B second belt layer cord fabric

[0162] 8 bead filler

[0163] 10 cap ply cord

[0164] C center line

Claims

1. A tire, comprising: A carcass having carcass cords; a belt layer including belt layer cords and arranged on the tire radial direction outer side of the carcass; a cap layer including cap layer cords containing polyester fibers and disposed on the outer side of the belt layer in the tire radial direction; and A tread, which is arranged on the outer side of the cap layer in the tire radial direction, The tire is characterized by: The belt layer cord is a cord composed of 4 filaments, The diameter of the cap layer cord and the diameter of the belt layer cord satisfy the following formula: |Diameter of cap layer cord - Diameter of belt layer cord|<0.40 in, The unit of the diameter of the band cord and the diameter of the belt cord is mm.

2. The tire according to claim 1, characterized in that The number of cords E per 50 mm width of the cap layer cord BA and the number of cords E per 50 mm width of the belt cords BE Satisfies the following formula, |And BA -AND BE |<30。 3. The tire according to claim 1, characterized in that The belt cord has a bending rigidity of less than 50 g·cm.

4. The tire according to claim 1, characterized in that The sum of the intermediate elongation and thermal shrinkage of the cap ply cord is less than 15, wherein the units of the intermediate elongation and thermal shrinkage of the cap ply cord are %.

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