Tire

Abstract

To provide a tire capable of further improving stability.SOLUTION: A tire comprises a carcass part, and a belt part. The carcass ply forming the carcass part is the carcass ply formed by using ply cords whose line density is greater than 4400 dtex, the belt part is formed by laminating at least two belt layers in which a steel cord formed of one filament is used as a belt cord. In addition, a diameter Pr (mm) of the ply cord, a diameter Br (mm) of the belt cord, and a tire radial distance Bg (mm) between belt cords in the adjacent belt layers satisfy the following formula: (Br+Bg) / Pr≤1.00.SELECTED DRAWING: Figure 1

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, and a band.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to further improve the handling stability.

Means for Solving the Problems

[0005] The present invention is a tire including a carcass part and a belt part, wherein the carcass ply constituting the carcass part is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, the belt part is formed by laminating at least two or more belt layers using a steel cord composed of one filament as a belt cord, and further, a tire characterized in that the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the tire radial direction distance Bg (mm) between the belt cords in adjacent belt layers satisfy the following formula. (Br + Bg) / Pr ≦ 1.00

Effects of the Invention

[0006] According to the present invention, further improvement in handling stability can be achieved.

Brief Description of the Drawings

[0007]

Figure 1

Embodiments for Carrying Out the Invention

[0008] [1] Features 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 is a tire including a carcass part and a belt part. The carcass ply constituting the carcass part is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, and the belt part is formed by laminating at least two or more belt layers using a steel cord composed of one filament as a belt cord. Further, the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the tire radial distance (belt gauge) Bg (mm) between the belt cords in adjacent belt layers satisfy the following formula. (Br + Bg) / Pr ≤ 1.00

[0010] By having these features, as described later, further improvement in handling stability can be achieved.

[0011] 2. Mechanism of Effect Expression in the Tire According to the Present Invention The mechanism of the above-described effect expression in the tire according to the present invention is considered as follows.

[0012] (1) Carcass Part In the tire according to the present invention, the carcass ply constituting the carcass part is a carcass ply formed using a ply cord having a linear density (also referred to as "total fineness") exceeding 4400 dtex.

[0013] By forming carcass plies using ply cords with a linear density exceeding 4400 dtex, which are thicker than conventional ply cords with a linear density of about 2200 to 4400 dtex, the lateral spring constant can be increased, and the degree of deflection generated in the side portion during operation can be changed (decreased). Therefore, it is considered that the handling stability can be improved. Note that the linear density of the ply cord is preferably 6600 dtex or less.

[0014] Note that the linear density of the ply cord described above can be measured in accordance with the method specified in JIS L1017:2002.

[0015] The carcass part may be configured using two or more carcass plies, but is preferably configured with one layer. By locking such a carcass part by folding it from the inside to the outside around the bead core, the axial bending rigidity can be sufficiently reduced, and when a camber angle is present during cornering, the side portion can be sufficiently deflected, allowing more of the tread surface to contact the ground. Therefore, it is considered that the handling stability can be improved. Note that in the examples described later, one or more carcass plies are used.

[0016] Also, by using such a carcass part, it is considered that the fuel efficiency of the tire can be improved.

[0017] (2) Belt part By forming a belt part by stacking at least two or more belt layers formed with a steel cord consisting of one filament (1×1 structure) as a belt cord, the cord diameter can be reduced, and the thickness of the rubber to be topped on the belt cord (topping gauge) can be made thinner. Therefore, it is considered that the weight of the tire can be reduced.

[0018] Here, the filament constituting the belt cord preferably has a circular cross-sectional shape, but may also be elliptical. Also, the filament is preferably without waves and without twist, and may be plated.

[0019] Furthermore, in the present invention, the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the distance Bg (mm) between the belts satisfy the following formula. (Br + Bg) / Pr ≤ 1.00

[0020] Thereby, the belt portion can be made thinner than the carcass ply, the shear rigidity during running is increased, and the response force to the lateral force is enhanced. Therefore, it is considered that the handling stability can be improved and the weight of the tire can be reduced.

[0021] Note that ((Br + Bg) / Pr) described above is more preferably 0.95 or less, and even more preferably 0.90 or less. On the other hand, the lower limit is not particularly limited, but it is preferably 0.60 or more, and more preferably 0.65 or more.

[0022] As described above, in the present invention, by appropriately forming the carcass portion and the belt portion, the above-described effects cooperate and are synergistically exhibited. Therefore, it is considered that the handling stability can be improved.

[0023] Note that in the above, the diameter of the cord refers to the diameter of the circumscribed circle of the cross section perpendicular to the extending direction of the cord when the circumscribed circle is a perfect circle. In the case of an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the perfect circle assumed when the cross-sectional area is the same).

[0024] Also, the distance Bg (belt gauge) in the tire radial direction between the belt cords in adjacent belt layers can be obtained by measuring the radial distance between the two belt cords (cross sections) on the equator when each belt cord in both belt layers exists on the equator in the tire meridian cross section. And when only one belt cord is on the equator and the other belt cord is not on the equator, it can be obtained by measuring the radial distance between the belt cord closest to the equator and the belt cord on the equator.

[0025] [2] More preferable embodiments of the tire according to the present invention By adopting the following embodiments, the tire according to the present invention can obtain a greater effect.

[0026] 1. Cord diameter of belt cord In the present invention, the cord diameter of the belt cord is preferably 0.29 mm or more and 0.42 mm or less. Thereby, since further thinning of the belt portion can be achieved, 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.

[0027] 2. Ends in carcass part and belt part In the present invention, the number of cords (ends) E per 50 mm width in the tire width direction of the carcass part CA and the number of cords (ends) E per 50 mm width in the tire width direction of the belt part BE If the difference between them is reduced to make the bending rigidity of the carcass part and the belt part close to each other, the balance between the deflection in the side part and the ground contact property in the tread part is improved, so that it is considered that further improvement in handling stability can be achieved.

[0028] Specifically, it is considered that further improvement in handling stability can be achieved by making the difference between the ends E CA of the carcass part and the ends E BE of the belt part 15 or less. That is, it is considered that further improvement in handling stability can be achieved if the following formula is satisfied. |E CA - E BE | ≦ 15

[0029] Note that the above |E CA - E BE | is more preferably 12 or less, further preferably 8 or less, and particularly preferably 5 or less.

[0030] 3. Ends of the Belt Portion In the present invention, the number of ends of the belt portion is preferably 45 or less, and more preferably 40 or less.

[0031] By reducing the ends in this way, the bending rigidity in the belt portion can be reduced, so that the grounding property in the tread portion is improved, and it is considered that further improvement in handling stability can be achieved.

[0032] 4. Intermediate Elongation and Heat Shrinkage Ratio of the Ply Cord In the present invention, it is preferable that both the intermediate elongation and the heat shrinkage ratio of the ply cord are low.

[0033] From the viewpoint of handling stability, generally, organic fiber cords with low intermediate elongation and high modulus, such as rayon, polyamide synthetic fiber, and polyester synthetic fiber, are preferably used as the ply cord. However, these fiber cords shrink during vulcanization, resulting in a decrease in modulus. Therefore, by reducing both the intermediate elongation and the heat shrinkage ratio to improve the modulus in the tire after vulcanization, it is considered that further improvement in handling stability can be achieved.

[0034] Specifically, the sum of the intermediate elongation (%) and the heat shrinkage ratio (%) of the ply cord is preferably less than 8.3, and more preferably 7.5 or less. Thereby, the modulus in the tire after vulcanization can be improved and the lateral spring constant can be increased, so that the deflection generated in the side portion can be reduced, and it is considered that further improvement in handling stability can be achieved.

[0035] The intermediate elongation (%) of the cord can be determined from the elongation (%) at a load of 132 N in the "load-elongation" curve of the cord obtained under the environment of room temperature (25°C ± 2°C) in accordance with "JIS L1017:2002 Test Methods for Chemical Fiber Tire Cords".

[0036] The heat shrinkage rate (%) of the cord is determined from the ratio y / x (%) of the amount of shrinkage y (mm) to the length x (mm) of the cord before standing (pre-cord) when the cord is left standing for 30 minutes at a temperature of 180°C in a no-load state, in accordance with "JIS L1017:2002 Test Methods for Chemical Fiber Tire Cords".

[0037] [3] Embodiments Hereinafter, the present invention will be specifically described based on the embodiments.

[0038] 1. Tire according to this embodiment FIG. 1 is a schematic cross-sectional view for explaining the structure of the tire according to this embodiment, showing a tire meridian cross-section including the rotation axis in the normal state of the tire.

[0039] Here, the "normal state" means that the tire is mounted on a normal rim, filled with a normal internal pressure, and is in a no-load state.

[0040] The "normal rim" is the rim defined for each tire in the standard system including the standard on which the tire is based. For example, in the case of JATMA (Japan Automobile Tire Manufacturers Association), it is the standard rim in the applicable sizes described in the "JATMA YEAR BOOK"; in the case of ETRTO (The European Tyre and Rim Technical Organisation), it is the "Measuring Rim" described in the "STANDARDS MANUAL"; in the case of TRA (The Tire and Rim Association, Inc.), it is the "Design Rim" described in the "YEAR BOOK". 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 defined by the standard, it refers to the rim that can be mounted on the tire and can hold the internal pressure, that is, among the rims that do not cause air leakage between the rim / tire, the one with the smallest rim diameter and then the narrowest rim width.

[0041] The "normal internal pressure" refers to the air pressure determined for each tire in the standard system including the standards on which the tire is based. For JATMA, it is the "maximum air pressure"; for ETRTO, it is the "INFLATION PRESSURE"; for TRA, it refers to the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". Refer to JATMA, ETRTO, and TRA in this order. If there is an applicable size during the reference, follow the relevant standard. For tires not specified in the standard, it refers to the normal internal pressure (however, not less than 250 KPa) of another tire size (specified in the standard) with the normal rim described as the standard rim. In the case where multiple normal internal pressures not less than 250 KPa are described, it refers to the minimum value among them.

[0042] As shown in FIG. 1, the tire 1 includes a carcass portion 6 extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a belt portion 7 disposed on the outer side in the tire radial direction of the carcass portion 6 and inside the tread portion 2. Note that C is the center line. In FIG. 1, the description of the band portion disposed between the carcass portion 6 and the tread portion 2 is omitted.

[0043] (1) Carcass portion The carcass portion 6 is composed of a single carcass ply 6A and is locked by turning from the inside to the outside around the bead core 5 of the bead portion 4 through the tread portion 2 and the sidewall portion 3 (1-0 structure).

[0044] In FIG. 1, 6a is the inner main body portion of the carcass ply 6A, and 6b is the outer turned-back portion. Between the inner main body portion 6a and the outer turned-back portion 6b, for example, a bead apex rubber 8 extending radially outward from the bead core 5 in the tire radial direction is disposed.

[0045] The carcass ply 6A is formed by topping both sides of a cord array body in which ply cords with a linear density exceeding 4400 dtex are arranged at predetermined ends with a predetermined rubber composition for the carcass ply (not shown).

[0046] By adopting such a carcass part 6, as described above, the lateral spring constant can be increased, and the degree of deflection generated in the side part during operation can be reduced, so it is considered that the handling stability can be improved.

[0047] As the ply cord, as described above, organic fiber cords with low intermediate elongation and high modulus, such as rayon, polyamide synthetic fiber, and polyester synthetic fiber, can be preferably used.

[0048] (2) Belt part The belt part 7 is arranged on the outside in the radial direction of the carcass part 6 and inside the tread part 2.

[0049] The belt part 7 is composed of one or more belts. In FIG. 1, the belt part 7 is composed of two belts, a first belt 7A located on the inner side in the tire radial direction and a second belt 7B located outside the first belt 7A. Note that three or more belts may be used.

[0050] The belt is made by topping both sides of a cord array body in which 1×1 structure steel cords (belt cords) are arranged at predetermined ends with a predetermined rubber composition for the belt and is made thinner than the carcass ply 6A (not shown).

[0051] By adopting such a belt part 7, as described above, the fuel efficiency of the tire 1 can be improved, and the shear rigidity during running is increased, so the response force to the lateral force is enhanced, and thus the handling stability can be improved.

[0052] 2. Use of sustainable materials In the tire according to the present invention, when manufacturing the above-mentioned belt, carcass ply, and other tire members, a predetermined rubber composition is used respectively. Considering the strong demand for environmental protection in recent years, it is preferable to use sustainable materials as the materials constituting this rubber composition.

[0053] (1) Rubber material For example, instead of raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR being derived from underground resources such as petroleum and natural gas, those recycled from rubber products such as tires and non-rubber products such as polystyrene can be used.

[0054] The monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, recycled aromatic vinyl, etc. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples include styrene. Among them, it is preferable to use recycled isoprene (recycled isoprene), butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0055] The method for producing recycled monomers is not particularly limited. For example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Also, the method for producing recycled naphtha is not particularly limited. For example, rubber products such as tires may be decomposed under high temperature and high pressure, decomposed by microwaves, or extracted after mechanical pulverization.

[0056] Furthermore, the raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR may be derived from biomass. Biomass refers to substances derived from natural resources such as plants. Biomass is not particularly limited, and examples include agricultural and forestry products, sugars, wood chips, plant residues after obtaining useful components, ethanol derived from plants, biomass naphtha, and the like. The monomers derived from biomass (biomass monomers) are not particularly limited, and examples include butadiene derived from biomass and aromatic vinyls derived from biomass. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyls are not particularly limited, and examples include styrene. Also, the method for producing biomass monomers is not particularly limited, and examples include those by biological and / or chemical and / or physical conversion of animals and plants. Fermentation by microorganisms is typical of biological conversion, and examples of chemical and / or physical conversion include those by catalysts, high heat, high pressure, electromagnetic waves, supercritical fluids, and combinations thereof.

[0057] The polymers synthesized from biomass monomer components (biomass polymers) are not particularly limited, and examples include polybutadiene rubber synthesized from butadiene derived from biomass, and aromatic vinyl / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyls derived from biomass. Examples of the aromatic vinyl / butadiene copolymers include styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass.

[0058] Whether the raw material of the polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured in accordance with ASTM D6866-10.

[0059] pMC is the 14 C concentration of the sample relative to that of the 14It is the ratio of C concentration and is a value used as an index indicating the biomass ratio of a compound. The significance of this value is described below.

[0060] In 1 mole (6.02×10 23 pieces) of carbon atoms, there are approximately 6.02×10 11 pieces, which is about one trillionth of ordinary carbon atoms. 14 14C exists. 14 14C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of these to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken up and fixed by plants and the like, in fossil fuels such as coal, oil, and natural gas, for which more than 226,000 years are considered to have passed since fixation, all of the 14 14C elements have decayed. Therefore, at present in the 21st century, fossil fuels such as coal, oil, and natural gas do not contain any 14 14C elements. Therefore, chemical substances produced from these fossil fuels also do not contain any 14 14C elements.

[0061] On the other hand, 14 14C is constantly generated by nuclear reactions of cosmic rays in the atmosphere, and a balance is maintained with the decrease due to radioactive decay. In the earth's atmospheric environment, the amount of 14 14C is a certain amount. Therefore, the 14 14C concentration of substances derived from biomass resources that are circulating in the current environment is about 1×10 -12 mol% with respect to the entire C atoms as described above. Therefore, by using the difference between these values, the biomass ratio in a certain compound (rubber) can be calculated.

[0062] This 14 14C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 14C concentration ( 13 14C / 12 12C), 14 13C concentration ( 14 13C / 12 12C) are measured. In the measurement,14 As a modern standard reference for the concentration of C, the concentration of 14 C in the circulating carbon in nature in 1950 is adopted. As a specific standard substance, 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 gram of carbon) is separated for each carbon isotope, 13 For 14 C, it is corrected to a constant value, and the value obtained by applying the decay correction from 1950 AD to the measurement date is used as the value of the standard

[0063] Therefore, if the rubber is made of a 100% biomass (natural-based) material, although there are regional differences and the like, it usually does not reach 100 in the current normal state, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when the 14 C concentration is measured, it will show a value of approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% mentioned above.

[0064] From the above, using materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in the rubber composition is suitable from the perspective of environmental protection.

[0065] Also, it is preferable to use vulcanized rubber particles as the rubber material.

[0066] Vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder etc. specified in JIS K 6316:2017 can be used. From the perspective of environmental consideration and cost, recycled rubber powder produced from crushed waste tires etc. is preferable. These can be used alone or in combination of two or more.

[0067] The vulcanized rubber particles are not particularly limited, and may be non-modified vulcanized rubber particles or modified vulcanized rubber particles.

[0068] As commercially available products of vulcanized rubber particles, for example, products of Lehigh, Murakami Rubber Industry Co., Ltd., etc. can be used.

[0069] (2) Silica Generally, silica is contained in the rubber composition as a reinforcing filler, but it is also preferable to use sustainable silica in place of raw materials derived from minerals such as quartz.

[0070] The silica is not particularly limited, and for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), etc., which are common in the tire industry, can be used. The raw material of silica is not particularly limited, and for example, it may be a raw material derived from a mineral such as quartz, or a raw material derived from a biological source such as rice husk (for example, silica made from a biomass material such as rice husk as a raw material), or silica recycled from a product containing silica may also be used. Among them, hydrous silica prepared by a wet method is preferable because it has many silanol groups. These silicas may be used alone or in combination of two or more.

[0071] Silica made from a biomass material can be obtained, for example, by extracting a silicate from rice husk ash obtained by burning rice husk using a sodium hydroxide solution, and reacting the silicate with sulfuric acid in the same manner as conventional wet silica to precipitate silicon dioxide, followed by filtration, washing with water, drying, and pulverization.

[0072] As the silica recycled from a product containing silica, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, and filter materials such as diatomaceous earth can be used. The recovery method is not particularly limited, and examples include pyrolysis and decomposition by electromagnetic waves. Among them, silica recovered from electronic components such as semiconductors or tires is preferable.

[0073] When silica crystallizes, it becomes insoluble in water and the silicic acid that is its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of silica in rice husk ash can be suppressed (see, for example, Japanese Patent Application Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0074] As the amorphous silica extracted from rice husks, those commercially available from Wilmar Co., Ltd. and others can be used.

[0075] (3) Carbon black And it is common for a rubber composition to contain carbon black as a reinforcing filler. As such carbon black, the use of sustainable carbon black (recycled carbon black) is also preferable.

[0076] The carbon black is not particularly limited, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw material of the carbon black may be a biomass material such as lignin or vegetable oil, or may be a pyrolysis oil obtained by pyrolyzing waste tires. Also, the manufacturing method of the carbon black may be by combustion such as the furnace method, may be by hydrothermal carbonization (HTC), or may be by thermal decomposition of methane such as the thermal black method. 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. These may be used alone or in combination of two or more.

[0077] (4) Oil Examples of oils commonly used as softeners for imparting plasticity to rubber components include mineral oils, vegetable oils, animal oils, etc. Also, from the perspective of life cycle assessment, it is also possible to use refined waste oil after use in rubber mixers or engines, or refined waste cooking oil used in restaurants. Mineral oil means an oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oils include paraffinic oils (mineral oils), naphthenic oils, aromatic oils, etc. Specific examples of process oils 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. Also, oils with a low content of polycyclic aromatic (PCA) compounds can be used for environmental measures. Examples of the low-PCA-content oils include MES, TDAE, and heavy naphthenic oils.

[0078] And specific examples of vegetable oils include, for example, 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, grape seed oil, wood rosin, etc. Furthermore, vegetable oils also include refined oils (such as salad oil) obtained by refining the above oils, transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, heat-polymerized oils obtained by thermally polymerizing the above oils, oxidation-polymerized oils obtained by oxidizing the above oils, and waste cooking oils and other vegetable oils recovered from those used as edible oils, etc. Note that 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.

[0079] The vegetable oil preferably contains acylglycerol, and more preferably contains triacylglycerol. Here, acylglycerol refers to a compound in which the hydroxy group of glycerin and a fatty acid are ester-bonded. The acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Further, the acylglycerol may be a monomer, a dimer, or a multimer of trimer or higher. Note that acylglycerols of dimer or higher can be obtained by thermal polymerization, oxidative polymerization, or the like. Also, the acylglycerol may be liquid or solid at room temperature (25 °C).

[0080] As a method for confirming whether or not the acylglycerol is contained in the rubber composition, it is not particularly limited, but 1 it can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25 °C) for 24 hours. After removing the rubber composition, 1 1H-NMR is measured. When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals are observed at around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm, and the signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. In this paragraph, "around" means a range of ±0.10 ppm.

[0081] The fatty acid is not particularly limited, and may be an unsaturated fatty acid or a saturated fatty acid. Examples of the unsaturated fatty acid include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of the saturated fatty acid include butyric acid and lauric acid.

[0082] Among these, as the fatty acid, it is desirable to contain a fatty acid with few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As the vegetable oil containing such a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or a vegetable oil subjected to modification such as transesterification may be used. Further, in order to produce a vegetable oil containing such a fatty acid, plants may be improved by variety improvement, gene recombination, genome editing, etc.

[0083] As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0084] (5) Plasticizers other than oil In the rubber composition, as a plasticizer that imparts plasticity to the rubber component, in addition to the above-mentioned oil, a plasticizer that is liquid at 25°C and a plasticizer that is solid at 25°C are also contained. Examples of such plasticizers include resin components, liquid polymers, ester plasticizers, etc. These plasticizers may be derived from mineral resources such as petroleum and natural gas, may be derived from biomass, or may be derived from naphtha recycled from rubber products and non-rubber products (sustainable plasticizers). Further, a low-molecular-weight hydrocarbon component obtained by pyrolyzing and extracting used tires and products containing various components may be used as a plasticizer. These plasticizers may be used alone or in combination of two or more.

[0085] (6) Wax Rubber compositions generally contain wax, and the wax is not particularly limited, and any wax commonly used in the tire industry can be preferably used. For example, mineral waxes, plant-derived waxes, etc. can be mentioned. 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. Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, etc. Examples of mineral waxes include paraffin wax, microcrystalline wax, and their selected special waxes, etc., and paraffin wax is preferred. As the wax, for example, those commercially available from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., etc. can be used. These waxes may be used alone or in combination of two or more.

[0086] (7) Antioxidant Rubber compositions generally contain antioxidants, although the antioxidants are not particularly limited. Examples of antioxidants 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'-ditoly-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-t-butyl-4-methylphenol and styrenated phenol; bis, tris, polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-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 commercial products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexsys, etc. can be used.

[0087] In the rubber composition, various materials containing carbon atoms (such as rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method for obtaining the formulation of the present invention from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation step of synthesizing methane from carbon dioxide may be converted.

[0088] 3. Manufacture of Tires The tire according to this embodiment can be manufactured by a normal method.

[0089] Specifically, on a forming drum, an inner liner part as a member for ensuring the airtightness of the tire, a carcass part as a member for withstanding the load, impact, and inflation pressure received by the tire, a belt part as a member for strongly tightening the carcass part to increase the rigidity of the tread, etc. are wound. At both side edges, bead parts as members for fixing both ends of the carcass ply and for fixing the tire to the rim are arranged, and after forming into a toroidal shape, a tread part is formed at the central part of the outer periphery, and a sidewall is bonded to the radially outer side to form a side part, thereby producing an unvulcanized tire. In this embodiment, the belt part may be composed of a plurality of layers from the viewpoint of increasing the tightening force on the carcass part during running and making it easier to increase the rigidity of the tread part. At this time, in the tire after vulcanization, the belt gauge Bg (mm) is preferably 0.6 mm or less.

[0090] Thereafter, the unvulcanized tire produced as described above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying known vulcanization means. The vulcanization temperature is, for example, above 120°C and below 200°C, and the vulcanization time is, for example, above 5 minutes and below 15 minutes.

[0091] As described above, the tire obtained as above appropriately forms the carcass part and the belt part, so that each effect cooperates and is synergistically exerted, and thus it is possible to appropriately achieve a balance between low fuel consumption of the tire and improvement of handling stability.

[0092] And the tire according to 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.

Examples

[0093] Hereinafter, examples (examples) considered to be preferable when implementing are shown, but the scope of the present invention is not limited to these examples.

[0094] Except for the carcass ply and belt of each specification shown in Table 1, they are substantially the same. For the tire with the configuration shown in FIG. 1 (tire size: 195 / 65R15), the results calculated based on the evaluation method described below regarding handling stability and low fuel consumption are also shown at the bottom of Table 1.

[0095] 1. Evaluation of Handling Stability A single test driver rides in a vehicle (a domestic FR vehicle with a displacement of 2000 cc) with each test tire mounted on all wheels and drives around a dry asphalt test course at a speed of 100 km / h. Then, each of the 20 test drivers subjectively evaluates the handling stability during driving based on characteristics such as steering response, stiffness feeling, and grip on a scale of 1 to 10 (the larger the numerical value, the better), and calculates the total score.

[0096] Next, taking the result in Comparative Example 1 as 100, it is indexed based on the following formula to obtain the handling stability evaluation. The larger the numerical value, the better the handling stability. Handling stability evaluation = [(Result of test tire) / (Result of Comparative Example 1)] × 100

[0097] 2. Evaluation of Low Fuel Consumption Using a rolling resistance tester, the rolling resistance coefficient RRC (Rolling Resistance Coefficient) when each test tire runs on a drum at a speed of 80 km / h under the following conditions is measured as an index for evaluating low fuel consumption. Rim used: 15 × 6J Inner pressure: 210 kPa Load: 4.35 kN

[0098] Next, taking the result in Comparative Example 1 as 100, it is indexed based on the following formula to obtain the low fuel consumption evaluation. The larger the numerical value, the better the low fuel consumption. Low fuel consumption evaluation = [(Result of Comparative Example 1) / (Result of test tire)] × 100

[0099] The overall performance is represented by the sum of the handling stability evaluation index and the low fuel consumption evaluation index obtained above.

[0100]

Table 1

[0101] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0102] The present invention (1) is a tire including a carcass part and a belt part, wherein the carcass ply constituting the carcass part is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, the belt part is formed by laminating at least two or more belt layers using a steel cord made of one filament as a belt cord, and further, the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the tire radial distance Bg (mm) between the belt cords in the adjacent belt layers satisfy the following formula, and the tire is characterized in that. (Br + Bg) / Pr ≤ 1.00

[0103] The present invention (2) is characterized in that the carcass part is composed of one layer of carcass ply, and is the tire according to the present invention (1).

[0104] The present invention (3) is characterized in that the cord diameter of the belt cord is 0.29 mm or more and 0.42 mm or less, and is the tire according to the present invention (1).

[0105] The present invention (4) is the number of cords E per 50 mm width in the tire width direction of the carcass part CA(This) and the number of cords E per 50 mm width in the tire width direction of the belt portion BE (This) satisfy the following formula, and it is the tire according to the present invention (1). |E CA -E BE |≤ 15

[0106] The present invention (5) is The number of cords E per 50 mm width in the tire width direction of the belt portion BE (This) is 45 or less, and it is the tire according to the present invention (1).

[0107] The present invention (6) is The sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the ply cord is less than 8.3, and it is the tire according to the present invention (1).

Explanation of reference numerals

[0108] 1 Tire 2 Tread portion 3 Sidewall portion 4 Bead portion 5 Bead core 6 Carcass portion 6A Carcass ply 6a Inner main body portion 6b Outer folded-back portion 7 Belt portion 7A First belt 7B Second belt 8 Bead apex rubber C Center line

Claims

1. A tire comprising a carcass part and a belt part, wherein the carcass ply constituting the carcass part is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, the belt part is formed by laminating at least two or more belt layers using a steel cord composed of one filament as a belt cord, and further, a tire characterized in that the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the tire radial direction distance Bg (mm) between the belt cords in the adjacent belt layers satisfy the following formula. (Br + Bg) / Pr ≤ 1.00

2. The tire according to claim 1, wherein the carcass part is composed of one layer of carcass ply.

3. The tire according to claim 1, wherein the cord diameter of the belt cord is 0.29 mm or more and 0.42 mm or less.

4. The number of cords E per 50 mm width in the tire width direction of the carcass part ＣＡ (book), and the number of cords E per 50 mm width in the tire width direction of the belt part ＢＥ (book) satisfy the following formula, and the tire according to claim 1 is characterized in that. |E ＣＡ -E ＢＥ |≤15

5. The number of cords E per 50 mm in the tire width direction of the belt part ＢＥ is 45 or less, and the tire according to claim 1 is characterized by this.

6. The tire according to claim 1, wherein the sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the ply cord is less than 8.3.

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