Tire

Abstract

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

Description

Technical Field

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

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

[0003] Prior Art Documents

[0004] Patent Documents

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

[0006] Problems to be Solved by the Invention

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

[0008] Means for Solving the Problems

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

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

[0011] the above belt layer portion is formed by overlapping at least two or more belt layers, and the belt layer is formed of belt layer cords having a structure in which four filaments are single-twisted,

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

[0013] (Br + Bg) / Pr ≤ 1.00

[0014] Effects of the Invention

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

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

[0017] Figure 2 is a view for explaining the diameter of the cord in the present invention. Detailed Description of the Invention

[0018] [1] Features of the Tire of the Present Invention

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

[0020] 1. Summary

[0021] The tire of the present invention is a tire having a carcass portion and a belt layer portion. Moreover, the carcass ply constituting the carcass portion is a carcass ply formed of carcass ply cords having a linear density exceeding 4400 dtex, and the belt layer portion is formed by overlapping at least two or more belt layers, and the belt layer is formed of belt layer cords having a structure in which four filaments are single-twisted (1×4 structure). Further, the diameter Pr (mm) of the carcass ply cord, the diameter Br (mm) of the belt layer cord, and the radial distance of the tire (belt layer thickness) Bg (mm) between the belt layer cords in adjacent belt layers satisfy the following formula.

[0022] (Br + Bg) / Pr ≤ 1.00

[0023] By having these characteristics, as described later, it is possible to further improve the handling stability.

[0024] 2. Mechanism of effect manifestation in the tire of the present invention

[0025] Regarding the mechanism of the above-described effect manifestation in the tire of the present invention, the following can be considered.

[0026] (1) Carcass portion

[0027] In the tire of the present invention, the carcass ply constituting the carcass portion is a carcass ply formed of carcass ply cords having a linear density (also referred to as "total fineness") exceeding 4400 dtex.

[0028] By forming the carcass ply with carcass ply cords having a linear density exceeding 4400 dtex, which is coarser than the existing carcass ply cords having a linear density of about 2200 to 4400 dtex, it is possible to increase the lateral spring constant and change (reduce) the degree of deflection generated in the sidewall portion during driving. Therefore, it is considered that the handling stability can be improved. It should be noted that the linear density of the carcass ply cord is preferably 6600 dtex or less.

[0029] It should be noted that the linear density of the above-described carcass ply cord can be measured according to the method specified in JIS L1017:2002.

[0030] The carcass portion is composed of one carcass ply, and is preferably locked by being folded back from the inside to the outside around the bead core. Thereby, it is possible to sufficiently reduce the axial bending rigidity, and when there is an outer camber angle during turning, the sidewall portion can be sufficiently bent, and more of the tread surface can contact the ground. Therefore, it is considered that the handling stability can be improved. It should be noted that the carcass portion may also be composed of two or more carcass plies.

[0031] In addition, by forming such a carcass part, it is considered that low fuel consumption of the tire can be achieved.

[0032] (2) Belt layer part

[0033] The belt layer part is formed by overlapping at least two layers of a belt layer formed of a steel cord (1×4 structure) composed of 4 filaments, whereby the cross-sectional shape of the belt layer cord can be made close to a circle, the cord diameter can be reduced, and the thickness of the rubber adhered to the belt layer cord (adhesive thickness) can be thinned. Therefore, it is considered that low fuel consumption of the tire can be achieved.

[0034] Here, the filaments constituting the belt layer cord preferably have a circular cross-sectional shape, but may also be elliptical. In addition, one or two or more of the 4 filaments may be corrugated, and plating treatment may also be performed.

[0035] In addition, in the present invention, the diameter Pr (mm) of the carcass ply cord, the diameter Br (mm) of the belt layer cord, and the belt layer interval thickness Bg (mm) satisfy the following formula.

[0036] (Br + Bg) / Pr ≤ 1.00

[0037] Thereby, the thickness of the belt layer part can be made thinner than the carcass ply, the shear rigidity during driving increases, and the response force to the lateral force improves. Therefore, it is considered that improvement in handling stability can be achieved, and low fuel consumption of the tire can be achieved.

[0038] It should be noted that the above ((Br + Bg) / Pr) is more preferably 0.95 or less, and further preferably 0.90 or less. On the other hand, there is no particular limitation on the lower limit, and it is preferably 0.80 or more, and more preferably 0.85 or more.

[0039] As described above, in the present invention, by appropriately forming the carcass part and the belt layer part, the above-mentioned various effects are synergistically multiplied, and therefore it is considered that improvement in handling stability can be achieved, and low fuel consumption of the tire can be achieved.

[0040] It should be noted that in the above text, regarding the diameter of the cord, in the case where the circumscribed circle of the cross-section perpendicular to the cord extension direction is a perfect circle, it refers to the diameter of the circumscribed circle, and in the case of an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the perfect circle when assuming the same cross-sectional area). As a specific example, Figure 2 shows the diameter of the 1×4 structure cord. It should be noted that Figure 2 in, the cord (large circle) is composed of 4 filaments (small circles), and D is the diameter of the cord.

[0041] In addition, regarding the radial distance of the belt cord in the adjacent belt layers (the thickness between the belt layers) Bg, when the belt cords in both belt layers are located on the equator in the tire meridian section, the radial distance between the two belt cords (their cross-sections) is measured on the equator, and thus it can be obtained. And when only the belt cord of one belt layer is on the equator and the belt cord of the other belt layer is not on the equator, the radial distance between the belt cord closest to the equator and the belt cord located on the equator is measured, and thus it can be obtained.

[0042] [2] A more preferred embodiment of the tire of the present invention

[0043] The tire of the present invention can achieve greater effects by adopting the following methods.

[0044] 1. Cord diameter of the belt cord

[0045] In the present invention, as the cord diameter of the belt cord, it is preferably 0.42 mm or more and 0.56 mm or less. Thus, since it is possible to further reduce the thickness of the belt layer portion, it is considered that it is possible to further improve the handling stability and to further reduce the fuel consumption of the tire. More preferably, it is 0.45 mm or more and 0.53 mm or less.

[0046] 2. Density in the carcass portion and the belt layer portion

[0047] In the present invention, if the number of cords per 50 mm width (density) E in the tire width direction of the carcass portion CA and the number of cords per 50 mm width (density) E in the tire width direction of the belt layer portion BE are made to have a difference such that the bending rigidities of the carcass portion and the belt layer portion are close values, then the balance between the flexure of the sidewall portion and the grounding property of the tread portion can be improved, and thus it is considered that the handling stability can be further improved.

[0048] Specifically, by making the difference between the density of the carcass portion and the density of the belt layer portion 15 or less, it is considered that the handling stability can be further improved. That is, if the following formula is satisfied, it is considered that the handling stability can be further improved.

[0049] |E CA -E BE |≤15

[0050] It should be noted that the above |E CA -E BE | is more preferably 10 or less, further preferably 5 or less, and particularly preferably 0.

[0051] 3. Density of the belt layer portion

[0052] In the present invention, the number of cords (density) per 50 mm width of the belt layer is preferably 45 or less, more preferably 40 or less.

[0053] By reducing the density in this way, the bending rigidity of the belt layer can be reduced, so the ground contact property of the tread portion is improved, and it is considered that a further improvement in handling stability can be achieved.

[0054] 4. Intermediate elongation and thermal shrinkage of carcass cords

[0055] In the present invention, the carcass cords preferably have both a low intermediate elongation and a low thermal shrinkage.

[0056] From the aspect of handling stability, as carcass cords, organic fiber cords such as rayon, polyamide synthetic fiber, and polyester synthetic fiber, which have a low intermediate elongation and a high modulus, are usually suitable. However, these fiber cords shrink thermally during vulcanization, resulting in a decrease in modulus. Therefore, it is considered that by reducing both the intermediate elongation and the thermal shrinkage, an increase in modulus in the vulcanized tire can be achieved, and thus a further improvement in handling stability can be achieved.

[0057] Specifically, the sum of the intermediate elongation (%) and the thermal shrinkage (%) of the carcass cords is preferably less than 8.3, more preferably 7.5 or less. Thereby, the modulus in the vulcanized tire can be increased, and the lateral spring constant can be increased. Therefore, it is considered that the flexure generated in the sidewall portion can be reduced, and a further improvement in handling stability can be achieved.

[0058] It should be noted that the intermediate elongation (%) of the cord can be obtained from the elongation (%) at a load of 132 N in the "load-elongation" curve of the cord obtained in an environment at room temperature (25°C ± 2°C) according to "JIS L1017:2002 Test Methods for Chemical Fiber Tire Cords".

[0059] In addition, the thermal shrinkage (%) of the cord can be obtained from the ratio y / x (%) of the shrinkage amount y (mm) to the length x (mm) of the cord (carcass cord) before placement when the cord is placed for 30 minutes at a temperature of 180°C in a load-free state according to "JIS L1017:2002 Test Methods for Chemical Fiber Tire Cords".

[0060] [3] Embodiments

[0061] Hereinafter, the present invention will be specifically described based on the embodiments.

[0062] 1. Tire of the present embodiment

[0063] Figure 1 is a schematic cross-sectional view showing the tire of the present embodiment, showing a tire meridian cross-section including the rotation axis in the normal state of the tire.

[0064] Here, the "normal state" means a state where the tire is mounted on a normal rim, filled with normal internal pressure, and has no load.

[0065] It should be noted that the "normal rim" refers to the rim specified for each tire in the standard system including the standard on which the tire is based. For example, if it is JATMA (Japan Automobile Tire Association), it refers to the standard rim in the applicable sizes recorded in the "JATMA YEARBOOK"; if it is ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" recorded in the "STANDARDS MANUAL"; if it is 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. 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.

[0066] And the "normal internal pressure" refers to the air pressure specified for each tire in the standard system including the standard on which the tire is based. If it is JATMA, it refers to the "maximum air pressure"; if it is ETRTO, it refers to the "INFLATION PRESSURE"; if it is 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 normal internal pressure of other tire sizes (specified in the standard) for which the above-mentioned normal rim is recorded as the standard rim (but above 250 KPa). It should be noted that in the case of multiple normal internal pressures above 250 KPa, it refers to the minimum value among them.

[0067] As Figure 1 shown, the tire 1 includes a tread portion 2, a sidewall portion 3, a bead portion 4, a carcass portion 6, and a belt layer portion 7. It should be noted that C is the center line.

[0068] (1) Carcass portion

[0069] The carcass part 6 is composed of one carcass ply 6A, and is locked by being folded back from the inside to the outside through the carcass cord 5 of the bead part 4 around the sidewall part 3 from the tread part 2.

[0070] It should be noted that Figure 1 Among them, 6a is the inner main body part of the carcass ply 6A, 6b is the outer folded-back part, and a bead apex 8 extending radially outward of the tire from the bead core 5 is disposed between the inner main body part 6a and the outer folded-back part 6b.

[0071] The carcass ply 6A is formed by applying a rubber composition for carcass ply specified on both sides of a cord arrangement body in which cord layers having a linear density exceeding 4400 dtex are arranged at a specified density (not shown).

[0072] By adopting such a carcass part 6, as described above, it is possible to increase the lateral spring constant and reduce the degree of flexure generated in the sidewall part during driving, and therefore it is considered that an improvement in handling stability can be achieved.

[0073] It should be noted that as the cord layers, as described above, organic fiber cords having a low intermediate elongation rate and a high modulus such as rayon, polyamide synthetic fiber, and polyester synthetic fiber can be suitably used. In the following examples, a cord layer cord containing polyethylene terephthalate (PET) fiber is used.

[0074] (2) Belt layer part

[0075] The belt layer part 7 is disposed on the radially outer side of the carcass part 6 and inside the tread part 2.

[0076] The belt layer part 7 is composed of one or more belt layers, Figure 1 Among them, it is composed of a first belt layer 7A located on the radially inner side of the tire and a second belt layer 7B located on the outer side of the first belt layer 7A. It should be noted that three or more belt layers can also be used.

[0077] The belt layer is formed by applying a rubber composition for belt layer specified on both sides of a cord arrangement body in which 1×4 structured belt layer cords are arranged at a specified density, and is made to have a thickness thinner than that of the carcass ply. The belt layer cords are preferably metal, especially steel. In the following examples, a 1×4 structured belt layer cord in which steel filaments having a circular cross-section are not corrugated and are single-twisted is used.

[0078] By adopting such a belt layer part 7, as described above, it is possible to achieve low fuel consumption of the tire, and the shear rigidity during driving increases, and the response force to the lateral force improves, and therefore it is considered that an improvement in handling stability can be achieved.

[0079] 2. Use of sustainable materials

[0080] In the tire of the present invention, the above-mentioned belt layer and carcass ply are produced by coating both sides of the cord arrangement body with a conventionally well-known rubber composition. 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.

[0081] (1) Rubber material

[0082] For example, the raw materials (monomers) of synthetic rubbers such as SBR and BR can be replaced with petroleum-derived raw materials by using raw materials recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0083] As the monomers obtained by recycling (recycled monomers), there is no particular limitation, and examples include recycled butadiene and recycled aromatic vinyl monomers. As butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. In addition, as the aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be mentioned. Among them, it is preferable to use recycled butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) as the raw materials.

[0084] As the manufacturing method of the recycled monomer, there is no particular limitation, and examples include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, as the manufacturing method of the recycled naphtha, there is no particular limitation. For example, rubber products such as tires can be decomposed under high temperature and high pressure, can be decomposed by microwave, or can be extracted after mechanical pulverization.

[0085] In addition, the raw materials (monomers) of synthetic rubbers such as SBR and BR can be derived from biomass. As the monomers derived from biomass (biomass monomers), there is no particular limitation, and examples include butadiene derived from biomass and aromatic vinyl monomers derived from biomass. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the above-mentioned aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be mentioned. In addition, the manufacturing method of the biomass monomer is not particularly limited, and examples include methods based on biological and / or chemical and / or physical conversion of animals and plants. As biological conversion, fermentation using microorganisms is representative, and as chemical and physical conversion, conversion using 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.

[0086] As polymers synthesized from biomass monomer components (biomass polymers), there is no particular limitation, and examples include polybutadiene rubber synthesized from butadiene derived from biomass, aromatic vinyl monomer / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl monomers derived from biomass, and the like. As the above-mentioned aromatic vinyl monomer / butadiene copolymer, for example, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be cited.

[0087] 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.

[0088] pMC refers to the 14 ratio of the C concentration of the sample to the 14 C concentration of the modern standard reference, and this value is used as an index representing the biomass ratio of the compound (rubber). The meaning of this value is as described below.

[0089] Among 1 mole (6.02×10 23 pieces) of carbon atoms, there are about one trillionth of ordinary carbon atoms, that is, about 6.02×10 11 pieces 14 of 14 C. 14 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken in and immobilized by plants and the like, it is considered that in fossil fuels such as coal, oil, and natural gas that have passed more than 226,000 years, all of the 14 C elements contained in these substances at the beginning of immobilization have decayed. Therefore, in the present of the 21st century, fossil fuels such as coal, oil, and natural gas do not contain 14 C elements at all. Therefore, chemical substances produced from these fossil fuels also do not contain

[0090] 14 C elements at all. 14 On the other hand, cosmic rays undergo nuclear reactions in the atmosphere and continuously generate 14 C, which is in balance with the decrease caused by radiation decay, and the amount of 14 C in the earth's atmospheric environment is a certain amount. Therefore, the -12Values around mol%. Therefore, by using the difference between these values, the proportion (biomass proportion) of the compound (from natural resources) in a certain compound (rubber) (compound from biomass resources) can be calculated.

[0091] This 14 C is usually measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ([[]] 13 C / [[[]] 12 C), [[[]] 14 C concentration ([[]] 14 C / [[[]] 12 C) are measured. In the measurement, the [[[]] 14 C concentration in the cyclic carbon in nature in 1950 is used as the [[[]] 14 C concentration reference, that 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, corrected to a certain value for [[[]] 13 C, and decay correction is performed 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.

[0092] Therefore, if rubber is made from a substance that is 100% 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 in the normal state). On the other hand, for chemical substances from fossil fuels such as petroleum, when measuring the [[[]] 14 C concentration, it shows approximately 0 pMC (for example, 0.3 pMC). This value corresponds to the biomass proportion of 0% mentioned above.

[0093] 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 proportion, in the rubber composition.

[0094] In addition, as the rubber material, vulcanized rubber particles are also preferably used.

[0095] 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.

[0096] As the vulcanized rubber particles, there is no particular limitation, and they can be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0097] As commercially available products of vulcanized rubber particles, products of companies such as Lehigh and Muraoka Rubber Industry Co., Ltd. can be used, for example.

[0098] (2) Silica

[0099] The rubber composition usually contains silica as a reinforcing filler, but it is also preferable to use sustainable silica in place of raw materials from minerals such as quartz.

[0100] As 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, and for example, it can be a raw material from minerals such as quartz, or a raw material 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.

[0101] 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, dried, and pulverized in the same manner as existing wet silica using this silicate, whereby it can be obtained.

[0102] Silica recycled from products containing silica can use, for example, silica recovered from products containing silica such as semiconductor and other electronic components, tires, desiccants, and filter materials such as diatomaceous earth. In addition, as the recovery method, there is no particular limitation, and thermal decomposition, decomposition using electromagnetic waves, etc. can be cited. Among them, silica recovered from semiconductor and other electronic components or tires is preferred.

[0103] If silica crystallizes, it is insoluble in water and the silicic acid as its component cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol. 6, p. 216-222, etc.).

[0104] Amorphous silica extracted from rice husks can use amorphous silica commercially available from companies such as Wilmar.

[0105] It should be noted that these silica can be used alone or in combination of two or more. It should be noted that from the aspect of environmental protection, it is suitable to use sustainable silica such as biomass silica and recycled silica.

[0106] (3) Carbon black

[0107] Moreover, the rubber composition usually further contains carbon black as a reinforcing filler. As such carbon black, it is also preferable to use sustainable carbon black.

[0108] There is no particular limitation on the carbon black, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc.

[0109] In addition to mineral oil, the raw materials of carbon black can also be biomass materials such as lignin and vegetable oil, and can also be pyrolysis oil (recycled carbon black) obtained by pyrolyzing rubber products containing carbon black such as waste tires. From the aspect of environmental protection, it is suitable to use these sustainable carbon blacks.

[0110] In addition, the manufacturing method of carbon black can be manufactured by combustion such as the furnace method, can also be manufactured by hydrothermal carbonization (HTC), and can also be manufactured by pyrolysis of methane based on the thermal cracking carbon black method, etc.

[0111] 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.

[0112] (4) Softening agent component

[0113] In the rubber composition, a softening agent component is used as needed from the aspect of imparting plasticity to the rubber component during mixing and appropriately dispersing the powder material. It should be noted that the softening agent component here is a concept including both softening agents that are liquid at 25°C and softening agents that are solid at 25°C.

[0114] Examples of the softening agent can include resin components, oils, liquid polymers, ester-based plasticizers, etc. These softening agents can be derived from mineral resources such as petroleum and natural gas, can also be derived from biomass, and can also be derived from naphtha recycled from rubber products and non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires or products containing various components can also be used as softening agents. Among them, softening agents derived from biomass or recycling are preferably used as sustainable softening agents.

[0115] It should be noted that these softeners can be used alone or in combination of two or more. The content of the plasticizer component relative to 100 parts by mass of the rubber component is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 25 parts by mass or more. As the upper limit, for example, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and further preferably 30 parts by mass or less. It should be noted that the content of the plasticizer component also includes the amount of oil contained in the rubber (oil-extended rubber) and the like.

[0116] (i)Oil

[0117] Examples of the oil include mineral oil, vegetable oil, animal oil, etc. In addition, from the perspective of life cycle assessment, oil refined from waste oil used in rubber mixers or engines, or waste cooking oil used in cooking shops may also be used.

[0118] (i-1) Mineral oil

[0119] Mineral oil refers to oil derived from mineral resources such as petroleum, natural gas, etc. Examples of the mineral oil include paraffinic oil (mineral oil), cycloparaffinic oil, and aromatic oil.

[0120] Specific examples of mineral oils include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract).

[0121] In addition, for environmental protection purposes, oils with low polycyclic aromatic compound (PCA) content may be used. Examples of such low PCA content process oils include MES, TDAE, and heavy naphthenic oils.

[0122] As commercially available mineral oils, for example, paraffinic, aromatic, cycloparaffinic, etc. oils can be cited, and for example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Olisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Manufacturing Co., Ltd., Showa Shell Sekiyu Co., Ltd., Fuji Kosan Co., Ltd. can be used. These can be used alone or in combination of two or more.

[0123] (i-2) Vegetable oil

[0124] 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, fragrant oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, and wood wax.

[0125] In addition, examples of 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 solid oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, and sustainable vegetable oils such as waste cooking oils recovered after use as cooking oils, etc. It should be noted that vegetable oils can be liquid or solid at room temperature (25°C). These vegetable oils can be used alone or in combination of two or more.

[0126] As vegetable oils, acylglycerols are preferably included, and triacylglycerols are more preferably included. It should be noted that acylglycerols refer to compounds in which the hydroxyl groups of glycerol form ester bonds with fatty acids. There is no particular limitation on acylglycerols, and they can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. In addition, acylglycerols can be monomers, dimers, or polymers of trimers or higher. It should be noted that acylglycerols of dimers or higher can be obtained by thermal polymerization or oxidative polymerization, etc. In addition, acylglycerols can be liquid or solid at room temperature (25°C).

[0127] As a method for confirming whether acylglycerols are contained in the rubber composition, there is no particular limitation, and it can be confirmed by 1 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room 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. It is speculated that these signals are signals from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. Therefore, it can be confirmed that acylglycerols are contained. It should be noted that "around" here refers to the range of ±0.10 ppm.

[0128] It should be noted that as fatty acids, there is no particular limitation, and they can be unsaturated fatty acids or saturated fatty acids. As unsaturated fatty acids, examples include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. In addition, as saturated fatty acids, examples include butyric acid and lauric acid.

[0129] Among them, as the above-mentioned fatty acids, it is preferable to contain fatty acids with fewer double bonds, that is, saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As vegetable oils containing such fatty acids, for example, vegetable oils containing saturated fatty acids or monounsaturated fatty acids can be used, or vegetable oils modified by transesterification or the like can be used. In addition, in order to produce vegetable oils containing such fatty acids, plants can also be improved through variety improvement, genetic recombination, genome editing, etc.

[0130] As vegetable oils, for example, commercially available vegetable oils from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY Corporation, H&R Corporation, Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0131] (ii) Liquid rubber

[0132] Liquid rubber refers to a polymer in a liquid state at normal temperature (25 °C), and it is a rubber component that can be extracted from vulcanized tires by acetone extraction. As liquid rubber, examples include farnesene-based polymers, liquid diene-based polymers, and their hydrides.

[0133] Farnesene-based polymers refer to polymers obtained by polymerizing farnesene and having structural units based on farnesene. Isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene) exist in farnesene.

[0134] Farnesene-based polymers can be homopolymers of farnesene (farnesene homopolymers) or copolymers of farnesene and vinyl monomers (farnesene-vinyl monomer copolymers).

[0135] As liquid diene-based polymers, examples include liquid styrene-butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), liquid styrene-isoprene copolymers (liquid SIR), etc.

[0136] The polystyrene-equivalent weight-average molecular weight (Mw) of liquid diene-based polymers measured by gel permeation chromatography (GPC) is, for example, more than 1.0×10 3 and less than 2.0×105 Here, the Mw of the liquid diene polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC).

[0137] As the liquid rubber, products of, for example, Kuraray Co., Ltd., Cray Valley Co., etc. can be used.

[0138] (iii) Resin component

[0139] The resin component also functions as an adhesion - imparting component. It can be solid or liquid at room temperature. As specific resin components, for example, rosin - based resins, styrene - based resins, benzofuran - based resins, terpene - based resins, C5 resins, C9 resins, C5C9 resins, acrylic - based resins, etc. can be cited, and two or more of them can be used in combination. It should be noted that these resin components can also be provided with modifying groups capable of reacting with silica, etc. as required.

[0140] The rosin - based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin - based resin (rosin) can be classified according to whether it is modified or not, and can be classified into unmodified rosin (unmodified rosin), rosin modifiers (rosin derivatives). As unmodified rosin, tall oil rosin (also known as tall oil pitch), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins can be cited. Rosin modifiers are modifiers of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid - modified rosins, unsaturated carboxylic acid - modified rosin esters, amide compounds of rosin, amine salts of rosin, etc.

[0141] The styrene - based resin is a polymer using styrene - based monomers as constituent monomers, and examples include polymers obtained by polymerizing styrene - based monomers as the main component (50% by mass or more). Specifically, in addition to homopolymers obtained by homopolymerizing each styrene - based monomer (styrene, o - methylstyrene, m - methylstyrene, p - methylstyrene, α - methylstyrene, p - methoxystyrene, p - tert - butylstyrene, p - phenylstyrene, o - chlorostyrene, m - chlorostyrene, p - chlorostyrene, etc.) and copolymers obtained by copolymerizing two or more styrene - based monomers, copolymers of styrene - based monomers and other monomers capable of copolymerizing with them can also be cited.

[0142] As the above - mentioned other monomers, examples include acrylonitrile - based compounds such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acid - based compounds such as acrylic acid and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, diene - based compounds such as chloroprene, butadiene, and isoprene, olefin - based compounds such as 1 - butene and 1 - pentene; α,β - unsaturated carboxylic acids or their acid anhydrides such as maleic anhydride; etc.

[0143] Among benzofuran-based resins, benzofuran-indene resins are preferred. Benzofuran-indene resins are resins containing benzofuran and indene as monomer components that constitute the resin backbone (main chain). Examples of monomer components contained in the backbone other than benzofuran and indene include styrene, α-methylstyrene, methyl indene, vinyltoluene, etc.

[0144] The hydroxyl value (OH value) of the benzofuran-indene resin, for example, exceeds 15 mgKOH / g and is less than 150 mgKOH / g. It should be noted that the OH value refers to the amount of potassium hydroxide required to neutralize acetic acid bonded to hydroxyl groups when 1 g of the resin is acetylated, expressed in milligrams, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0145] The softening point of the benzofuran-indene resin, for example, exceeds 30 °C and is less than 160 °C. It should be noted that the softening point is the softening point specified in JIS K 6220-1:2001 measured using a ring and ball softening point apparatus, which is the temperature at which the ball drops.

[0146] Examples of terpene-based resins include polyterpene, terpene phenol, aromatic modified terpene resin, etc. Polyterpene is a resin obtained by polymerizing terpene compounds and its hydrides. Terpene compounds are hydrocarbons and their oxygen-containing derivatives represented by the composition of (C5H8) n and are compounds with a basic skeleton of terpenes classified as monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ), etc. Examples include α-pinene, β-pinene, dipentene, limonene, myrcene, allo-ocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0147] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. which are made from the above-mentioned terpene compounds as raw materials, hydrogenated terpene resins obtained by hydrogenating the terpene resins can also be cited. As terpene phenols, resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating such resins can be cited. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formaldehyde can be cited. It should be noted that as phenolic compounds, for example, phenol, bisphenol A, cresol, xylenol, etc. can be cited. As aromatic-modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating such resins can be cited. It should be noted that as aromatic compounds, as long as they are compounds having an aromatic ring, there is no particular limitation, and for example, phenol compounds such as phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, styrene containing an unsaturated hydrocarbon group; benzofuran, indene, etc. can be cited.

[0148] “C5 resin” refers to a resin obtained by polymerizing a C5 fraction. As the C5 fraction, for example, petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. can be cited. As C5-based petroleum resins, dicyclopentadiene resin (DCPD resin) is preferably used.

[0149] “C9 resin” refers to a resin obtained by polymerizing a C9 fraction, and can also be a resin obtained by hydrogenating or modifying them. As the C9 fraction, for example, petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, methylindene, etc. can be cited. As a specific example, for example, benzofuran indene resin, benzofuran resin, indene resin and aromatic vinyl-based resins are preferably used. As aromatic vinyl-based resins, due to reasons such as economy, easy processing, and excellent heat generation properties, α-methylstyrene (AMS resin) or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As aromatic vinyl-based resins, for example, aromatic vinyl-based resins commercially available from KRATON Corporation, Eastman Chemical Company, etc. can be used.

[0150] “C5C9 resin” refers to a resin obtained by copolymerizing the above-mentioned C5 fraction and the above-mentioned C9 fraction, and can also be a resin obtained by hydrogenating or modifying them. As the C5 fraction and the C9 fraction, the above-mentioned petroleum fractions can be cited. As C5C9 resins, for example, resins commercially available from Tosoh Corporation, LUHUA Company, etc. can be used.

[0151] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0152] Solvent-free acrylic resins include (meth) acrylic resins (polymers) synthesized by a high temperature continuous polymerization method (high temperature continuous bulk polymerization method) (methods described in U.S. Patent No. 4,414,370, Japanese Patent Publication No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Publication No. 1-313522, U.S. Patent No. 5,010,166, East Asia Synthesis Research Annual Report TREND 2000 No. 3, p. 42-45, etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as secondary raw materials as much as possible. It should be noted that in the present invention, (meth) acrylic acid refers to methacrylic acid and acrylic acid.

[0153] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, arylalkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0154] As monomer components constituting the acrylic resin, aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or a (meth)acrylic acid derivative.

[0155] The acrylic resin may be a resin composed only of a (meth)acrylic acid component or a resin containing components other than the (meth)acrylic acid component as constituent elements. In addition, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0156] As the resin component, for example, products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, KRATON, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0157] (6) Wax

[0158] The rubber composition generally contains wax. The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples thereof include mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among them, mineral waxes are preferred.

[0159] As plant-derived waxes, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As petroleum-based waxes, for example, paraffin wax, microcrystalline wax, their selected special waxes, etc. can be cited, and paraffin wax is preferred. It should be noted that in the present invention, wax does not include stearic acid.

[0160] It should be noted that as the wax, for example, waxes commercially available from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Corporation, etc. can be used. These waxes can be used alone or in combination of two or more.

[0161] (7) Antioxidant

[0162] Antioxidants are 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, 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), 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, styrenated phenol; bisphenol-based, triphenol-based, 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. They can be used alone or in combination of two or more. As commercial products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexis Corporation, etc. can be used.

[0163] It should be noted that in the rubber composition, various materials containing carbon atoms among the above-mentioned materials (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.

[0164] 3. Manufacture of tires

[0165] The tire of the present embodiment can be manufactured by a conventional method.

[0166] Specifically, on a building drum, a liner layer portion as a component for ensuring the airtightness retention of the tire, a carcass portion as a component for bearing the load, impact, and inflation pressure of the tire, a belt layer portion as a component for strongly clamping the carcass portion and improving the tread rigidity, etc. are wound. While fixing both ends of the carcass ply at both side edges, a bead portion as a component for fixing the tire to a rim is arranged. After being formed into a ring shape, by attaching a tread portion to the central portion of the outer periphery and attaching a sidewall to the radially outer side to form a sidewall portion, an unvulcanized tire is produced.

[0167] Then, the tire is obtained by heating and pressurizing the above-produced unvulcanized tire in a vulcanizer. The vulcanization process can be implemented by applying known vulcanization means. As the vulcanization temperature, for example, it exceeds 120 °C and is less than 200 °C, and the vulcanization time is, for example, more than 5 minutes and less than 15 minutes.

[0168] In the tire obtained above, as described above, the carcass portion and the belt layer portion are appropriately formed, whereby each effect is synergistically multiplied, so that an improvement in handling stability can be achieved, and a reduction in tire fuel consumption can be achieved.

[0169] 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.

[0170] Examples

[0171] The following shows examples (embodiments) considered to be preferable during implementation, but the scope of the present invention is not limited to these embodiments.

[0172] For tires having substantially the same constitution except for the carcass ply and belt layer of each specification shown in Table 1 Figure 1 (tire size: 195 / 65R15) as shown, regarding handling stability and low fuel consumption, calculations were made based on the evaluation methods described later, and the results are shown together in the lower part of Table 1.

[0173] 1. Evaluation of handling stability

[0174] One test driver rode in a vehicle (domestic FR vehicle, displacement 2000 cc) with each test tire mounted on all wheels and drove around on a dry asphalt test track at a speed of 100 km / h. And 20 test drivers respectively made a sensory evaluation of the handling stability during driving based on characteristics such as steering wheel responsiveness, rigidity feeling, and grip, etc., on a scale of 1 - 10 points (the larger the value, the better), and the total score was calculated.

[0175] Next, set the result in Comparative Example 1 to 100 and perform exponentiation based on the following formula as the handling stability evaluation. The larger the value, the better the handling stability.

[0176] Handling stability evaluation = [(Result of the test tire) / (Result of Comparative Example 1)] × 100

[0177] 2. Evaluation of low fuel consumption

[0178] Using a rolling resistance testing machine, measure the rolling resistance coefficient RRC (Rolling Resistance Coefficient) of each test tire when traveling on a drum at a speed of 80 km / h under the following conditions as an index for evaluating low fuel consumption.

[0179] Rim used: 15 × 6J

[0180] Inner pressure: 210 kPa

[0181] Load: 4.35 kN

[0182] Next, set the result in Comparative Example 1 to 100 and perform exponentiation based on the following formula as the low fuel consumption evaluation. The larger the value, the better the low fuel consumption.

[0183] Low fuel consumption evaluation = [(Result of Comparative Example 1) / (Result of the test tire)] × 100

[0184] (3) Comprehensive performance

[0185] The comprehensive performance is represented by the sum of the respective indices of the above handling stability and low fuel consumption.

[0186] [Table 1]

[0187]

[0188] 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.

[0189] The present invention (1) relates to a tire having a carcass portion and a belt layer portion, characterized in that

[0190] The carcass ply constituting the above carcass portion is a carcass ply formed of carcass ply cords having a linear density exceeding 4400 dtex,

[0191] The above belt layer portion is formed by overlapping at least two or more belt layers, and the belt layer is formed of belt layer cords having a structure in which four filaments are single-twisted,

[0192] Furthermore, the diameter Pr (mm) of the cord in the carcass ply, the diameter Br (mm) of the cord in the belt ply, and the radial distance Bg (mm) between the cords in the belt ply in adjacent belt plies satisfy the following formula.

[0193] (Br + Bg) / Pr ≤ 1.00

[0194] The tire according to the present invention (2) as described in the present invention (1), characterized in that the carcass part is composed of one carcass ply.

[0195] The tire according to the present invention (3) as described in the present invention (1), characterized in that the cord diameter of the belt ply cord is 0.42 mm or more and 0.56 mm or less.

[0196] The tire according to the present invention (4) as described in the present invention (1), characterized in that the number of cords E CA (pieces) per 50 mm width in the tire width direction of the carcass part and the number of cords E BE (pieces) per 50 mm width in the belt part satisfy the following formula.

[0197] |E CA - E BE | ≤ 15

[0198] The tire according to the present invention (5) as described in the present invention (1), characterized in that the number of cords E BE per 50 mm width in the tire width direction of the belt part is 45 or less.

[0199] The tire according to the present invention (6) as described in the present invention (1), characterized in that the sum of the intermediate elongation rate (%) and the heat shrinkage rate (%) of the cord in the carcass ply is less than 8.3.

[0200] Symbol Explanation

[0201] 1 Tire

[0202] 2 Tread

[0203] 3 Sidewall

[0204] 4 Bead

[0205] 5 Bead core

[0206] 6 Carcass part

[0207] 6A Carcass ply

[0208] 6a Inner main body part

[0209] 6b Outer folded-back part

[0210] 7 Belt part

[0211] 7A Belt Ply 1

[0212] 7B Belt Ply 2

[0213] 8 Bead Filler

[0214] C Center Line

Claims

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

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

3. The tire according to claim 1, characterized in that The belt cords have a cord diameter of 0.42 mm or more and 0.56 mm or less.

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

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

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

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