Tire

Abstract

To improve stability.SOLUTION: A tire has a carcass part and a belt part. A carcass ply forming the carcass part is a carcass ply which is formed by a ply cord whose line density is greater than 4400 dtex, the belt part is formed by laminating at least two belt layers which are formed of a belt cord obtained by single twisting four filaments. 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 the belt cords in 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 bead portion, a carcass portion, a belt portion, and a band portion.

Prior Art Documents

Patent Documents

[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 portion and a belt portion, wherein the carcass ply constituting the carcass portion is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, the belt portion is formed by laminating at least two or more belt layers formed using a belt cord having a structure in which four filaments are single-twisted, 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 distance Bg (mm) between the belt cords in the 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

Figure 2

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 provided with 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 formed using a belt cord having a structure in which four filaments are single-twisted (1×4 structure). Further, the diameter Pr (mm) of the ply cord, the diameter Br (mm) of the belt cord, and the tire radial direction distance (belt gap) 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 will be 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 the carcass ply using a ply cord having a linear density exceeding 4400 dtex, which is thicker than the conventional ply cords having 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 part during driving 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] 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 is preferably composed of a single carcass ply and is locked by turning back from the inside to the outside around the bead core. Thereby, the bending rigidity in the axial direction can be sufficiently reduced, and when a camber angle is present during cornering, the side part can be sufficiently deflected, and the tread surface can be brought into contact with the ground more. Therefore, it is considered that the handling stability can be improved. Note that the carcass part may be configured using two or more carcass plies.

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

[0017] (2) Belt part By forming at least two or more belt layers by stacking belt layers formed with steel cords composed of four filaments (1×4 structure) as belt cords, the cross-sectional shape of the belt cords can be made closer to a circular shape, the cord diameter can be reduced, and the thickness of the rubber (topping gauge) topping the belt cords can be made thinner. Therefore, it is considered that the fuel efficiency of the tire can be improved.

[0018] Here, the filaments constituting the belt cord preferably have a circular cross-sectional shape, but may also be elliptical. And among the four filaments, one or two or more filaments may be corrugated and may also 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 belt-to-belt gauge Bg (mm) 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 fuel efficiency of the tire can be improved.

[0021] Note that the above ((Br + Bg) / Pr) 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 is preferably 0.80 or more, and more preferably 0.85 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 exerted. Therefore, it is considered that the handling stability can be improved and the fuel efficiency of the tire can be improved.

[0023] 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 of the cross-section 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). As a specific example, FIG. 2 shows the diameter of the cord in a 1×4 structure cord. In FIG. 2, the cord (large circle) is composed of four filaments (small circles), and D is the diameter of the cord.

[0024] In addition, the tire radial distance (belt gauge) Bg between belt cords in adjacent belt layers can be obtained by measuring the radial distance of the two belt cords (in cross-section) at the equator when each belt cord in both belt layers is located 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 preferred 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 the belt cord In the present invention, the cord diameter of the belt cord is preferably 0.42 mm or more and 0.56 mm or less. Thereby, further thinning of the belt part can be achieved, so that further improvement in handling stability can be achieved and further reduction in fuel consumption of the tire can be achieved. More preferably, it is 0.45 mm or more and 0.53 mm or less.

[0027] 2. Ends in the carcass part and the 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 When the difference between them is reduced to make the bending stiffness of the carcass part and the belt part close to each other, the balance between the deflection in the side part and the grounding performance in the tread part is improved, so that further improvement in handling stability can be achieved.

[0028] Specifically, it is considered that further improvement in handling stability can be achieved by setting the difference between the ends of the carcass part and the ends of the belt part to 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] In addition, the above |E CA -E BE | is more preferably 10 or less, even more preferably 5 or less, and particularly preferably 0.

[0030] 3. Ends of the belt part In the present invention, the number of cord strands (ends) per 50 mm width of the belt part 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 part can be reduced, so that the grounding performance in the tread part is improved, and it is considered that further improvement in handling stability can be achieved.

[0032] 4. Intermediate elongation and heat shrinkage rate of the ply cord In the present invention, the ply cord preferably has both a low intermediate elongation and a low heat shrinkage rate.

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

[0034] Specifically, the sum of the intermediate elongation (%) and the heat shrinkage rate (%) of the ply cord is preferably less than 8.3, and more preferably 7.5 or less. Thereby, since the modulus in the tire after vulcanization can be improved and the lateral spring constant can be increased, it is considered that the deflection generated in the side portion can be reduced and 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 can be determined from the ratio y / x (%) of the amount of shrinkage y (mm) to the length x (mm) of the cord (ply cord) before leaving it in a state of no load and at a temperature of 180°C for 30 minutes in accordance with "JIS L1017:2002 Test Methods for Chemical Fiber Tire Cords".

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

[0038] 1. Tire according to this embodiment FIG. 1 is a schematic cross-sectional view for explaining the tire according to this embodiment, and shows 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 rim-mounted on a normal rim, filled with a normal internal pressure, and in a no-load state.

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

[0041] The "regular internal pressure" refers to the air pressure defined for each tire in the standard system including the standards on which the tire is based. In the case of JATMA, it refers to the "maximum air pressure"; in the case of ETRTO, it refers to the "INFLATION PRESSURE"; and in the case of 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, and follow the relevant standards if there are applicable sizes. For tires not defined by the standards, it refers to the regular internal pressure (however, 250 KPa or more) of another tire size (defined by the standards) with the regular rim described as the standard rim. If there are multiple regular internal pressures of 250 KPa or more, it refers to the minimum value among them.

[0042] As shown in FIG. 1, the tire 1 includes a tread portion 2, a sidewall portion 3, a bead portion 4, a carcass portion 6, and a belt portion 7. Note that C is the center line.

[0043] (1) Carcass portion The carcass part 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 part 4 through the sidewall part 3 from the tread part 2.

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

[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 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 driving 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. In the examples described later, a ply cord containing polyethylene terephthalate (PET) fiber is used.

[0048] (2) Belt part The belt part 7 is arranged on the outside in the radius 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, it is composed of a first belt 7A located on the inner side in the tire radius 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 belt cords having a 1×4 structure are arranged at predetermined ends with a predetermined rubber composition for the belt, and is made to have a thinner gauge than the carcass ply. The belt cords are preferably made of metal, particularly steel. In the examples described later, a belt cord having a 1×4 structure in which steel filaments having a circular cross-section are single-twisted without being corrugated is used.

[0051] By adopting such a belt portion 7, as described above, it is possible to achieve low fuel consumption of the tire, and at the same time, the shear rigidity during running is increased and the response force to lateral force is enhanced, so it is considered that the handling stability can be improved.

[0052] 2. Use of Sustainable Materials In the tire according to the present invention, the above-mentioned belt and carcass ply are produced by coating both sides of the cord array body with a conventionally 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.

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

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

[0055] The method for producing the recycled monomer is not particularly limited, and for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Further, the method for producing recycled naphtha is not particularly limited, and 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) of synthetic rubbers such as SBR and BR may be derived from biomass. The monomer derived from biomass (biomass monomer) is not particularly limited, and examples include biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples include styrene. The method for producing the biomass monomer 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. Examples of the biomass sources of these monomers include sugars, wood, plant residues after obtaining useful components, plant-derived ethanol, biomass naphtha, and the like.

[0057] The polymer synthesized from the biomass monomer component (biomass polymer) is not particularly limited, and examples include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[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 ratio of the 14 C concentration of the sample to the 14 C concentration of the standard modern reference, and this value is used as an index indicating the biomass ratio of the compound (rubber). The significance of this value will be described below.

[0060] In one mole (6.02×10 23 atoms) of carbon atoms, there are approximately 6.02×10 11 atoms of 14 C, which is about one trillionth of the normal carbon atoms. 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 these to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are considered to have passed more than 226,000 years after carbon dioxide in the atmosphere was taken up and fixed by plants, etc., all of the 14 C elements contained in them at the time of fixation have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas do not contain any 14 C elements. Therefore, chemical substances produced from these fossil fuels as raw materials also do not contain any 14 C elements.

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

[0062] This 14 C is generally 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) is measured. In the measurement, 14 As a modern standard reference for the concentration of 14 C, the concentration of 14 C in the circulating carbon in nature in 1950 is adopted. As a specific reference material, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific activity of carbon in this oxalic acid (radioactivity intensity of 13 C per gram of carbon) is fractionated for each carbon isotope, 14 C is corrected to a constant value, and the value after applying the decay correction from 1950 AD to the measurement date is used as the value of the standard

[0063] C concentration (100%). The ratio of this value to the value of the sample actually measured is the pMC value. 14 Therefore, if the rubber is manufactured from a 100% biomass (natural) - derived substance, despite regional differences and the like, it will show a value of approximately 110 pMC (currently, in the normal state, it often does not reach 100). On the other hand, for chemical substances derived from fossil fuels such as petroleum, when the

[0064] From the above, it is preferable in terms of environmental protection to use materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in the rubber composition.

[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 viewpoints of environmental consideration and cost, recycled rubber powder produced from crushed waste tires etc. is preferable. These may 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 Industries 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 the dry method (anhydrous silica), silica prepared by the 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, a raw material derived from a living organism such as rice husk (for example, silica using a biomass material such as rice husk as a raw material), or silica recycled from a product containing silica may be used. Among them, hydrous silica prepared by the 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 biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and reacting the silicate with sulfuric acid in the same manner as conventional wet silica, followed by filtering, washing with water, drying, and pulverizing the resulting silicon dioxide precipitate.

[0072] As the silica recycled from products 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 preferred.

[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] Amorphous silica extracted from rice husks can be those commercially available from companies such as Wilmar.

[0075] These silicas may be used alone or in combination of two or more. Using sustainable silicas such as biomass silica and recycled silica is preferable from the perspective of environmental protection.

[0076] (3) Carbon black It is also common for carbon black to be contained as a reinforcing filler in the rubber composition, and it is preferable to use sustainable carbon black as such carbon black.

[0077] The carbon black is not particularly limited, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc.

[0078] In addition to mineral oil, the raw material of carbon black may also be biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by pyrolyzing rubber products containing carbon black such as waste tires (recycled carbon black). Using these sustainable carbon blacks is preferable from the perspective of environmental protection.

[0079] Also, the manufacturing method of carbon black may be by combustion such as the furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane such as the thermal black method.

[0080] As commercially available products, products of companies such as Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon can be used. These may be used alone or in combination of two or more.

[0081] (4) Softening agent component In the rubber composition, from the perspective of imparting plasticity to the rubber component and appropriately dispersing the powder material during kneading, a softening agent component is used as necessary. Here, the softening agent component is a concept including both softeners that are liquid at 25°C and softeners that are solid at 25°C.

[0082] Examples of softening agents include resin components, oils, liquid polymers, ester plasticizers, etc. These softening agents may be derived from mineral resources such as petroleum and natural gas, may be biomass-derived, or may be derived from naphtha recycled from rubber products or non-rubber products. Also, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires and products containing various components may be used as softening agents. Among these, biomass-derived and recycled-derived softening agents are preferable as sustainable softening agents.

[0083] These softeners may 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 still more preferably 25 parts by mass or more. The upper limit is preferably, for example, 40 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less. Note that the content of the plasticizer component includes the amount of oil contained in rubber (oil-extended rubber) and the like.

[0084] (i) Oil Examples of the oil include mineral oil, vegetable oil, animal oil, etc. Also, from the perspective of life cycle assessment, it is also possible to use refined waste oil after being used in a rubber mixer or an engine, or refined waste cooking oil used in a cooking shop.

[0085] (i-1) Mineral oil Mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, aromatic oil, etc.

[0086] Specific examples of mineral oil include, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc.

[0087] Also, it is possible to use oil with a low content of polycyclic aromatic (polycyclic aromatic compound: PCA) compounds for environmental protection. Examples of the low-PCA content process oil include MES, TDAE, heavy naphthenic oil, etc.

[0088] Examples of commercially available mineral oils include oils such as paraffinic, aromatic, and naphthenic oils. For example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., H&R Co., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd., etc. can be used. These may be used alone or in combination of two or more.

[0089] (i-2) Vegetable oil Examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc.

[0090] Furthermore, examples of vegetable oils 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, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidation polymerized oils obtained by oxidizing the above oils, and sustainable vegetable oils such as waste edible 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.

[0091] Vegetable oils preferably contain acylglycerol, and more preferably contain triacylglycerol. Note that acylglycerol refers to a compound in which the hydroxy group of glycerin and a fatty acid are ester-bonded. Acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a multimer of three or more. Note that acylglycerol dimers or more can be obtained by thermal polymerization, oxidation polymerization, etc. Also, acylglycerol may be liquid or solid at room temperature (25°C).

[0092] As a method for confirming whether acylglycerol is contained in the rubber composition, although not particularly limited, 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, at room temperature 1 1H-NMR is measured. When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals are observed around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm. Since these signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group, the presence of acylglycerol can be confirmed. Here, "around" refers to the range of ±0.10 ppm.

[0093] The fatty acid is not particularly limited and may be an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0094] Among them, 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. In addition, in order to produce a vegetable oil containing such a fatty acid, plants may be improved by variety improvement, genetic recombination, genome editing, etc.

[0095] 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.

[0096] (ii) Liquid rubber Liquid rubber is a polymer in a liquid state at room temperature (25 °C) and is a rubber component that can be extracted from the vulcanized tire by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0097] A farnesene-based polymer is a polymer obtained by polymerizing farnesene and has a structural unit based on farnesene. Farnesene has 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).

[0098] The farnesene-based polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0099] Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like.

[0100] The liquid diene-based polymer has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of, for example, more than 1.0×10 3 ultra and less than 2.0×10 5 Here, the Mw of the liquid diene-based polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0101] As the liquid rubber, for example, products of Kuraray Co., Ltd., Kray Valley Co., Ltd., etc. can be used.

[0102] (iii) Resin component The resin component also functions as an adhesiveness-imparting component and may be solid or liquid at normal temperature. Specific resin components include, for example, resins such as rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins, and two or more of them may be used in combination. In addition, these resin components may be provided with a modifying group capable of reacting with silica or the like as necessary.

[0103] The rosin-based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin-based resin (rosins) can be classified according to the presence or absence of modification, and can be classified into unmodified rosin (unmodified rosin) and rosin modified products (rosin derivatives). Examples of unmodified rosin include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin modified products are modified products of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosins, unsaturated carboxylic acid-modified rosin esters, amide compounds of rosin, and amine salts of rosin.

[0104] The styrene-based resin is a polymer using a styrene-based monomer as a constituent monomer, and examples include polymers polymerized with a styrene-based monomer as a main component (50% by mass or more). Specifically, homopolymers obtained by polymerizing 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.) alone, copolymers obtained by copolymerizing two or more styrene-based monomers, and copolymers of a styrene-based monomer and other monomers copolymerizable therewith are also included.

[0105] Examples of the other monomer include acrylonitriles such as acrylonitrile and methacrylonitrile, acrylates, unsaturated carboxylic acids such as methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene, butadiene and isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or their acid anhydrides; and the like.

[0106] Among coumarone resins, coumarone-indene resins are preferred. A coumarone-indene resin is a resin containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyltoluene and the like.

[0107] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value represents the amount of potassium hydroxide in milligrams required to neutralize acetic acid bonded to hydroxyl groups when 1 g of the resin is acetylated, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0108] The softening point of the coumarone-indene resin is, for example, more than 30 °C and less than 160 °C. The softening point is the temperature at which the ball drops when measured with a ring and ball softening point measuring device according to the softening point defined in JIS K 6220-1:2001.

[0109] Examples of terpene resins include polyterpenes, terpene phenols, aromatic modified terpene resins and the like. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are hydrocarbons represented by the composition of (C5H8) n and their oxygen-containing derivatives, monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H32 ) It is a compound having a terpene as a basic skeleton and classified into, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, allo-ocimene, ocimene, α-farnesene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0110] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. using the above-mentioned terpene compounds as raw materials, and hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating the resins. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formalin are included. Examples of phenolic compounds include phenol, bisphenol A, cresol, xylenol, etc. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the resins. The aromatic compound is not particularly limited as long as it has an aromatic ring. Examples include phenolic 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; coumarone, indene, etc.

[0111] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of the C5 fraction include petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0112] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which may be hydrogenated or modified. Examples of the C9 fraction include petroleum fractions equivalent to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. As specific examples, for instance, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resins are preferably used. Among the aromatic vinyl resins, due to economic reasons, ease of processing, and excellent heat generation properties, a homopolymer of α-methylstyrene (AMS resin) or styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As the aromatic vinyl resin, for example, those commercially available from companies such as Kraton Corporation and Eastman Chemical Company can be used.

[0113] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, which may be hydrogenated or modified. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As the C5C9 resin, for example, those commercially available from companies such as Tosoh Corporation and LUHUA can be used.

[0114] The acrylic resin is not particularly limited, and for example, a solventless acrylic resin can be used.

[0115] The solventless acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (the methods described in U.S. Patent No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Patent No. 5,010,166, Annual Report of Toagosei Research TREND2000 No. 3 p42-45, etc.) without using a polymerization initiator, chain transfer agent, organic solvent, etc. as auxiliary raw materials as much as possible. In the present invention, "(meth)acrylic" means methacrylic and acrylic.

[0116] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (such as alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0117] In addition, as the monomer components constituting the acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0118] The acrylic resin may be a resin composed only of the (meth)acrylic component or a resin having components other than the (meth)acrylic component as constituent elements. Further, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, etc.

[0119] Examples of the resin component include products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nippon Paint Co., Ltd., Nippon Catalyst Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., Tago Chemical Industry Co., Ltd., etc.

[0120] (6) Wax Generally, wax is contained in the rubber composition. The wax is not particularly limited, and any of those commonly used in the tire industry can be preferably used. For example, mineral waxes, plant-derived waxes, etc. may be mentioned. 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.

[0121] Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, and the like. Examples of petroleum-based waxes include paraffin wax, microcrystalline wax, and these selected special waxes, etc., with paraffin wax being preferred. In the present invention, the wax shall not contain stearic acid.

[0122] As the wax, for example, those commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramoelt Co., etc. can be used. These waxes may be used alone or in combination of two or more. (7) Antioxidant Rubber compositions generally contain antioxidants. The antioxidants are not particularly limited, but 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. These may be used alone or in combination of two or more. As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexsys, etc. can be used.

[0123] In the rubber composition, among the above-mentioned various materials, various materials containing carbon atoms (for example, 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.

[0124] 3. Tire Manufacturing The tire according to the present embodiment can be manufactured by a normal method.

[0125] 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 clamping the carcass part to increase the rigidity of the tread, etc. are wound, and at both side edges, both ends of the carcass ply are fixed, and a bead part as a member for fixing the tire to the rim is 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.

[0126] 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.

[0127] As described above, the tire obtained as above can improve the handling stability and achieve low fuel consumption of the tire because the respective effects cooperate and are synergistically exerted by appropriately forming the carcass part and the belt part.

[0128] 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.

Example

[0129] Hereinafter, examples (examples) considered to be preferable when implementing are shown, but the scope of the present invention is not limited to the said examples.

[0130] For the carcass ply and components other than the belt of each specification shown in Table 1, they are substantially the same. Regarding the tire with the configuration shown in Fig. 1 (tire size: 195 / 65R15), the results calculated based on the evaluation method described below for handling stability and low fuel consumption are also shown at the bottom of Table 1.

[0131] 1. Evaluation of Handling Stability A single test driver gets into a vehicle (a domestic FR vehicle with a displacement of 2000 cc) equipped with each test tire 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.

[0132] 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

[0133] 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 in use: 15 × 6J Inner pressure: 210 kPa Load: 4.35 kN

[0134] 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

[0135] (3) Comprehensive Performance The overall performance is represented by the sum of the above-described indexes of handling stability and low fuel consumption.

[0136]

Table 1

[0137] 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.

[0138] 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 formed using a belt cord having a structure in which four filaments are single-twisted, 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

[0139] The present invention (2) is characterized in that the carcass part is constituted by one layer of carcass ply, and is the tire according to the present invention (1).

[0140] The present invention (3) is characterized in that the cord diameter of the belt cord is 0.42 mm or more and 0.56 mm or less, and is the tire according to the present invention (1).

[0141] 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 of the belt part BE (This) satisfy the following formula, and it is the tire according to the present invention (1). |E CA -E BE |≤15

[0142] The present invention (5) The number of cords E per 50 mm width in the tire width direction of the belt part BE is 45 or less, and it is the tire according to the present invention (1).

[0143] The present invention (6) 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 symbols

[0144] 1 Tire 2 Tread part 3 Sidewall part 4 Bead part 5 Bead core 6 Carcass part 6A Carcass ply 6a Inner main body part 6b Outer folded-back part 7 Belt part 7A First belt 7B Second belt 8 Bead apex rubber C Center line

Claims

1. A tire comprising a carcass portion and a belt portion, wherein the carcass ply constituting the carcass portion is a carcass ply formed using a ply cord having a linear density exceeding 4400 dtex, the belt portion is formed by laminating at least two or more belt layers formed using a belt cord having a structure in which four filaments are single-twisted, furthermore, 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 portion is constituted by one carcass ply.

3. The tire according to claim 1, wherein the cord diameter of the belt cord is 0.42 mm or more and 0.56 mm or less.

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

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.

Images