tire

Abstract

To provide a tire having excellent durability during high-speed driving.SOLUTION: A tire includes a tread portion and a belt-reinforcing layer, the belt-reinforcing layer containing a reinforcement material comprising a compound represented by the formula (1) in the figure, where m is 2 or 3 and n is an integer. The tire satisfies the specified formula (2), where d (mm) refers to the equivalent cross-sectional diameter of the reinforcement material, and L (mm) refers to the distance from the tread groove bottom to the belt-reinforcing layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to tires. [Background technology]

[0002] Various methods have been considered to improve tire performance, such as durability, but in recent years, there has been a particular demand for improved durability, especially at high speeds. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] This disclosure aims to solve the aforementioned problems and provide a tire with excellent durability during high-speed driving. [Means for solving the problem]

[0004] This disclosure relates to a tire having a tread portion and a belt reinforcement layer, The belt reinforcement layer includes a reinforcing material made of a compound represented by the following formula (1): [ka] (In the formula, m is 2 or 3, and n is an integer.) The present invention relates to a tire in which the uniform cross-sectional area diameter d (mm) of the reinforcing material and the distance L (mm) from the bottom of the tread groove to the belt reinforcing layer satisfy the following formula (2). (2) d / L ≤ 0.80 [Effects of the Invention]

[0005] This disclosure provides a tire having a tread portion and a belt reinforcement layer, wherein the belt reinforcement layer includes a reinforcing material made of a compound represented by formula (1) and satisfies formula (2), thereby providing a tire with excellent durability at high speeds. [Brief explanation of the drawing]

[0006] [Figure 1]This is a cross-sectional view of a pneumatic tire in this disclosure. [Figure 2] Figure 1 shows an enlarged view of the belt layer and belt reinforcement layer. [Figure 3] This is a close-up view of the tread area. [Modes for carrying out the invention]

[0007] This disclosure relates to a tire having a tread portion and a belt reinforcement layer, wherein the belt reinforcement layer includes a reinforcing material made of a compound represented by formula (1), and the equicross-sectional area diameter d (mm) of the reinforcing material and the distance L (mm) from the bottom of the tread groove to the belt reinforcement layer satisfy formula (2).

[0008] The reasons for the aforementioned effects are not entirely clear, but it is presumed that they are achieved through the following mechanism. During high-speed driving, the centrifugal force acting on the tread is significant, making it prone to deformation. Therefore, further improvements in durability are desired. In this disclosure, the belt reinforcement layer uses a compound represented by formula (1) in which the chain length in the dicarboxylic acid is longer than that of conventional nylon 6,6. As a result, the distance of hydrogen bonds formed within the polyamide is longer between the dicarboxylic acids. Therefore, it is thought that the molecular chains can be stretched to a moderate degree, making it less likely to break even when centrifugal force is large. At the same time, it is thought that by using diamines at a level equivalent to or lowering the number of carbon atoms compared to conventional diamines, hydrogen bonds can be formed over short distances, thereby maintaining or improving their strength. In particular, by setting the number of carbon atoms in the carboxylic acid to 10, it is thought that regular crystallinity can be obtained without other polyamide molecules becoming entangled in the carboxylic acid portion. Furthermore, by extending the chain length of the carboxylic acid, the carbon chain bonded to the oxygen atom is restricted to planar movement only, making it easier to obtain good crystallinity even with a long carbon chain. Also, when the distance from the belt reinforcing layer to the bottom of the tread groove becomes short, the deformation of the tread portion during rolling is likely to be transmitted to the cords in the belt reinforcing layer, raising concerns about breakage. On the other hand, if the equivalent cross-sectional area diameter of the reinforcing material becomes too large relative to the distance to the groove bottom, there is a concern that the deformation of the tread portion will relatively increase and strain will concentrate at the interface with the belt reinforcing layer. Therefore, by setting the ratio of the equivalent cross-sectional area diameter of the reinforcing material to the distance from the belt reinforcing layer to the bottom of the tread groove as in formula (2), it is considered possible to suppress the concentration of strain in the reinforcing material and at the interface. Due to the above functions, it is speculated that in the present disclosure, the durability during high-speed driving can be improved.

[0009] Thus, by configuring the tire to have a tread that satisfies the formula (2) "d / L ≤ 0.80" for the equivalent cross-sectional area diameter d of the reinforcing material and the distance L from the bottom of the tread groove to the belt reinforcing layer, the problem (objective) of improving the durability during high-speed driving is solved. That is, the parameter of the formula (2) "d / L ≤ 0.80" does not define the problem (objective). The problem of the present application is to improve the durability during high-speed driving, and for this purpose, the configuration is made to satisfy the said parameter.

[0010] Hereinafter, an embodiment of the present disclosure will be described based on the drawings, but this is only one embodiment, and the tire of the present disclosure is not limited to the following form.

[0011] FIG. 1 is an example of a right half tire meridian cross-sectional view including the tire rotation axis (not shown) in the normal state of the pneumatic tire (hereinafter sometimes simply referred to as "tire") 1 of the present embodiment. In FIG. 1, for example, a tire 1 for a passenger car is shown. However, the present invention can also be applied to tires 1 for motorcycles, heavy loads, etc.

[0012] The "normal state" is a state where the tire 1 is rim-mounted on a normal rim (not shown), filled with a normal internal pressure, and is unloaded.

[0013] The aforementioned "standard rim" refers to the rim defined for each tire in the standards system, including the standard on which tire 1 is based. For example, it is the "standard rim" for JATMA, the "Design Rim" for TRA, and the "Measuring Rim" for ETRTO.

[0014] The aforementioned "standard internal pressure" is the air pressure specified for each tire in the standards system, including the standard on which tire 1 is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0015] The tire 1 of this embodiment includes a belt layer 7 embedded inside the tread portion 2. The belt layer 7 includes at least one belt ply 8. The tire 1 is provided with a belt reinforcing layer 15 on the radially outer side of the belt layer 7. The tire 1 also includes a carcass 6 of a well-known structure, for example, positioned radially inside the belt layer 7 and spanning between the bead portions 4 on both sides.

[0016] Figure 2 is an enlarged view of the belt ply 8 and the belt reinforcement layer 15. As shown in Figure 2, the belt ply 8 includes a belt cord 9 and a topping rubber 10 covering the belt cord 9. In this embodiment, the belt cord 9 is a single wire with a circular cross-section, but it is not limited to this, and may be a cord with an M×N structure formed by twisting together M filament bundles of N strands. Furthermore, the cross-sectional shape of each filament is not limited to a circular shape, but may be an elliptical, polygonal, or other shape. In addition, these filaments may be pre-shaped for durability and other reasons.

[0017] As shown in Figure 2, the belt ply 8 includes, for example, a first belt ply 8A and a second belt ply 8B adjacent to the first belt ply 8A in the tire radial direction. The second belt ply 8B is located, for example, outside the first belt ply 8A in the tire radial direction.

[0018] The axial width W1 of the first belt ply 8A is preferably, for example, 70% to 100% of the tread width TW. The axial width W2 of the second belt ply 8B is preferably, for example, 65% to 90% of the tread width TW. Furthermore, the width of the second belt ply is preferably smaller than the width of the first belt ply.

[0019] The tread width TW is the distance in the axial direction of the tire between the tread ends Te located on both sides in the axial direction of the tire. The tread end Te is the outermost contact point in the axial direction of the tire when a normal load is applied to the tire 1 in the normal state and it makes contact with a plane at a camber angle of 0°. This distance between the contact ends can be determined by measuring in the axial direction of the tire while fixing the width between the bead portions of the cross section cut radially from the tire to match the normal rim width. Similarly, the first belt ply width W1 and the second belt ply width W2 can be determined by measuring the distance between their respective ends in the axial direction of the tire while fixing the width between the bead portions of the cross section cut radially from the tire to match the normal rim width.

[0020] The aforementioned "standard load" is the load specified for each tire in the standards system, including the standard on which tire 1 is based. For JATMA, it is the "maximum load capacity," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "LOAD CAPACITY."

[0021] In this embodiment, the belt cord 9 is shown to be made of steel cord. Such a belt cord 9 suppresses deformation of the belt ply 8 during operation. The belt cord 9 may also be made of an organic fiber cord such as aramid. The belt cord 9 of the first belt ply 8A and the belt cord 9 of the second belt ply 8B may be made of the same material and have the same shape, or they may be made of different materials and have different shapes.

[0022] The belt cord 9 is preferably inclined at an angle of 15 to 45 degrees with respect to the circumferential direction of the tire.

[0023] While not particularly limited, it is desirable that the belt cords 9 of the first belt ply 8A and the belt cords 9 of the second belt ply 8B be arranged so that they intersect with each other, with their inclinations in the circumferential direction of the tire being in opposite directions.

[0024] From the viewpoint of adhesion to the rubber composition covering its periphery, the belt cord 9 is preferably plated with copper and zinc on its surface. Furthermore, it is more preferable that, in addition to the aforementioned copper and zinc, the belt cord 9 is plated with metal elements such as cobalt, nickel, bismuth, and antimony, whose ionization tendencies fall between those of copper and zinc.

[0025] Furthermore, from the viewpoint of adhesion to the surrounding rubber composition, it is preferable that the belt cord 9 has a layer of polybenzoxazine compound on its surface.

[0026] The topping rubber 10 covering the belt cord 9 preferably contains, in addition to well-known rubber materials, phenolic thermosetting resins, silica, salts of metals whose ionization tendency is between copper and zinc (such as cobalt, nickel, bismuth, and antimony) and organic fatty acids, polybenzoxazine compounds, and the like.

[0027] The belt ply 8 preferably has 30 to 100 belt cords 9 per 50 mm width, and more preferably 30 to 80 belt cords. Furthermore, the number of belt cords 9 per 50 mm width (cords / 50 mm) and the cross-sectional area of ​​the belt cord (mm²) are also important. 2 The cross-sectional area of ​​the cord per 50 mm in the tire width direction is 4.5 mm², which is the product of the two factors. 2 It is preferable that it be 50 mm or more, and 4.8 mm 2 A length of 50mm or more is more preferable.

[0028] In tire 1, the belt reinforcement layer 15 enhances the restraint of each belt ply 8A and 8B, thereby improving durability during high-speed driving. Furthermore, the belt reinforcement layer 15 may have two layers only at both ends.

[0029] The belt reinforcement layer width W3 (the width of the belt reinforcement layer 15 in the tire axial direction) can also be determined in the same way as the tread width TW, by fixing the width between the bead portions of the cross-sectional sections cut radially from the tire to match the regular rim width, and then measuring the distance between each end of the belt reinforcement layer 15 in the tire axial direction.

[0030] The belt reinforcement layer 15 includes a reinforcing material 16 (reinforcing cord) and a reinforcing rubber 17 (covering rubber composition for belt reinforcement layer) that covers the reinforcing cord 16.

[0031] The reinforcing material 16 (reinforcing cord) of the belt reinforcement layer 15 uses a compound represented by the following formula (1) (fatty acid polyamide). [ka] (In the formula, m is 2 or 3, and n is an integer.)

[0032] In the formula, the lower limit of n is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more, and the upper limit is preferably 10000 or less, more preferably 5000 or less, and even more preferably 1000 or less. When it is within the above range, the effect can be suitably obtained.

[0033] Examples of compounds represented by formula (1) include poly(hexamethylene sebakamid) (nylon 6,10) and poly(tetramethylene sebakamid) (nylon 4,10). These may be used individually or in combination of two or more.

[0034] The aliphatic diamine units and aliphatic dicarboxylic acid units that make up poly(hexamethylene sebakamid) (nylon 6,10) are hexamethylenediamine units and sebaic acid units, respectively. The aliphatic diamine units and aliphatic dicarboxylic acid units that make up poly(tetramethylene sebakamid) (nylon 4,10) are tetramethylenediamine units and sebaic acid units, respectively.

[0035] Poly(hexamethylene sebakamid) (nylon 6,10) and poly(tetramethylene sebakamid) (nylon 4,10), which have the above-mentioned structural units, can be produced, for example, by polycondensation of a diamine and a dicarboxylic acid.

[0036] The relative viscosity of the compound represented by formula (1) (fatty acid polyamide) is preferably 1.5 or higher, more preferably 1.8 or higher, even more preferably 2.0 or higher, and also preferably 5.5 or lower, more preferably 5.3 or lower, and even more preferably 5.0 or lower. Within the above range, the effect is suitably obtained. In this disclosure, the relative viscosity is the value measured in 96% by mass sulfuric acid at a concentration of 1% by mass and 25°C, in accordance with JIS K-6920.

[0037] The melting point of the compound represented by formula (1) (fatty acid polyamide) is preferably 150°C or higher, more preferably 170°C or higher, even more preferably 180°C or higher, and also preferably 245°C or lower, more preferably 235°C or lower, even more preferably 230°C or lower, and particularly preferably 225°C or lower. Within the above range, the effect can be suitably obtained. In this disclosure, the melting point is determined using a differential scanning calorimeter (DSC), with a sample volume of approximately 1 mg, nitrogen flowing as the ambient gas at 30 mL / min, and a heating rate of 10 °C / min. The value is obtained from the peak temperature of the endothermic peak observed when the sample is heated to a temperature above the melting point expected from room temperature and melted.

[0038] The reinforcing material 16 (reinforcing cord) using the compound (fatty acid polyamide) represented by formula (1) above is preferably formed from a cord with a twist count of 9.0 to 65.0 (t / 10cm). The twist count is preferably 10.0 t / 10cm or more, more preferably 20.0 t / 10cm or more, even more preferably 25.0 t / 10cm or more, and particularly preferably 31.5 t / 10cm or more. The upper limit is preferably 60.0 t / 10cm or less, more preferably 50.0 t / 10cm or less, even more preferably 42.0 t / 10cm or less, and particularly preferably 35.0 t / 10cm or less. Within the above range, the effect can be suitably obtained.

[0039] When the number of twists is within a predetermined range, the reason why the aforementioned effects are obtained is not entirely clear, but it is presumed that they are achieved through the following mechanism. By increasing the number of twists above the lower limit, the reinforcing material can stretch appropriately when external forces are applied during high-speed driving, allowing it to conform to the deformation and thus suppress delamination at the interface. Conversely, by keeping the number below the upper limit, excessive stretching due to centrifugal force during high-speed driving is suppressed, and it is presumed that durability during high-speed driving will be significantly improved.

[0040] The reinforcing material 16 (reinforcing cord) using the compound (fatty acid polyamide) represented by formula (1) above is preferably formed from a cord with a total fineness of 450 to 5500 dtex. The total fineness is preferably 500 dtex or more, more preferably 2800 dtex or more, even more preferably 3500 dtex or more, and particularly preferably 4200 dtex or more. The upper limit is preferably 5000 dtex or less, more preferably 4600 dtex or less, even more preferably 4500 dtex or less, and particularly preferably 4400 dtex or less. Within the above range, the effect can be suitably obtained.

[0041] When the total fineness is within a predetermined range, the reason why the aforementioned effects are obtained is not entirely clear, but it is presumed that they are achieved through the following mechanism. By increasing the total fiber density above the lower limit, the density within the reinforcing material increases, making it easier to obtain strength. On the other hand, by keeping it below the upper limit, the rubber of adjacent members can penetrate between the reinforcing materials, and damage caused by the concentration of strain in that area is less likely to be suppressed, resulting in good durability, which is presumed to significantly improve durability during high-speed driving.

[0042] The compound represented by formula (1) (fatty acid polyamide) may be made using renewable raw materials for at least part of its composition. For example, using the compound represented by formula (1) made using vegetable oil-based materials (such as castor oil) instead of mineral oil-based materials is advantageous from the standpoint of resource conservation.

[0043] The reinforcing material 16 (reinforcing cord) may contain other materials in addition to poly(hexamethylene sebamid) (nylon 6,10) and poly(tetramethylene sebamid) (nylon 4,10).

[0044] Other materials include poly(6-aminohexanoic acid) (nylon 6), also known as poly(caprolactam), poly(laurolactam) (nylon 12), poly(hexamethyleneadipamide) (nylon 6,6), poly(7-aminoheptanoic acid) (nylon 7), poly(8-aminooctanoic acid) (nylon 8), poly(9-aminononanoic acid) (nylon 9), poly(10-aminodecanoic acid) (nylon 10), poly(11-aminoundecanoic acid) (nylon 11), poly(decamethylenesebacamide) (nylon 10,10), poly Examples of aliphatic polyamides include (hexamethyleneazeramide) (nylon 6,9), poly(tetramethyleneadipamide) (nylon 4,6), poly(pentamethyleneadipamide) (nylon 5,6), poly(pentamethylenesebacamide) (nylon 5,10), hexamethyleneadipamide-caprolactam copolymer (nylon 6,6 / 6), poly[methylenebis(2-methylcyclohexyl)dodecamide] (nylon MACM12), and poly[4,4'-methylenebis(cyclohexyl)dodecamide] (nylon PACM12). These may be used individually or in combination of two or more.

[0045] The reinforcing material 16 (reinforcing cord) may use nylon 6,10 or nylon 4,10 individually, or two or more types in combination. The method of combination is not particularly limited, but examples include twisting each filament together to form a single cord, or arranging each fiber within the belt reinforcing layer 15. From the viewpoint of obtaining a suitable effect, it is preferable to use a hybrid cord made by twisting together two types of fibers with different stiffnesses for the reinforcing material 16 (reinforcing cord).

[0046] Examples of hybrid cords include hybrid cords made of polyester fibers and nylon 6,10 and / or nylon 4,10, and hybrid cords made of aramid fibers and nylon 6,10 and / or nylon 4,10.

[0047] The reinforcing material 16 (reinforcing cord) should preferably have an equal cross-sectional area diameter d (mm) that satisfies the following formula. 0.14mm <d<2.300mm d is preferably more than 0.20 mm, more preferably 0.28 mm or more, still more preferably more than 0.68 mm, and particularly preferably more than 0.83 mm. The upper limit is preferably less than 1.20 mm, more preferably less than 1.00 mm, still more preferably less than 0.95 mm, and particularly preferably less than 0.90 mm. When within the above range, the effect can be preferably obtained.

[0048] When the equal cross-sectional area diameter d is within a predetermined range, particularly 0.20 mm < d < 1.00 mm, the reason for obtaining the above-described effects is not necessarily clear, but it is presumed to be due to the following mechanism. By setting d to be not less than the lower limit, the strength of the reinforcing material can be easily obtained and the durability during high-speed driving is improved. By setting it to be not more than the upper limit, the rubber of the member adjacent to the reinforcing materials can be prevented from intruding, and it is easy to suppress damage caused by the concentration of strain at that portion. Therefore, good durability can be obtained, and it is presumed that the durability during high-speed driving is remarkably improved.

[0049] In the present disclosure, the equal cross-sectional area diameter of the reinforcing material 16 (reinforcing cord) refers to the diameter of a circle having the same area as the actual cross-sectional area of the reinforcing material 16 (reinforcing cord). In a state where the width between the beads of the cross-section section obtained by cutting the tire in the radial direction is fixed to the normal rim width, the average cross-sectional area of the reinforcing material 16 measured in the range of ±50 mm in the tire width direction from the tire equatorial plane is calculated, and it can be obtained from the diameter of the circle having the same area as the average cross-sectional area.

[0050] The reinforcing material 16 (reinforcing cord) is preferably arranged, for example, at an angle within ±10° with respect to the tire circumferential direction. Thereby, the restraint in the circumferential direction of the tire can be enhanced, and the durability performance can be improved. In the present embodiment, the cross-section of the reinforcing material 16 (reinforcing cord) is circular, but it is not limited to circular ones, and other shapes such as elliptical or polygonal cross-sections are also acceptable.

[0051] Furthermore, from the viewpoint of obtaining a suitable effect, it is desirable that the reinforcing material 16 (reinforcing cord) be arranged in the tire axial direction with a density of 30 to 80 reinforcing cords per 50 mm width. The lower limit is preferably 34 or more, more preferably 45 or more, and the upper limit is preferably 78 or less, more preferably 68 or less.

[0052] When the number of reinforcing cords driven in (ends) is within a predetermined range, the reason why the aforementioned effects are obtained is not entirely clear, but it is presumed that they are achieved through the following mechanism. By setting the end value above the lower limit, the density of the reinforcing material within the reinforcing layer increases, improving the restraining force and ensuring durability during high-speed driving. Conversely, by setting it below the upper limit, good adhesion with the coating rubber layer is ensured, resulting in good durability, which is presumed to significantly improve durability during high-speed driving.

[0053] From the viewpoint of obtaining a suitable effect, it is desirable that the ratio (%) of the cross-sectional area of ​​the reinforcing material 16 (reinforcing cord) to the belt reinforcing layer 15 per 50 mm width in the tire axial direction be 15 to 55%. The lower limit is preferably 25% or more, more preferably 30% or more, even more preferably 35% or more, and particularly preferably 40% or more, and the upper limit is preferably 50% or less, more preferably 45% or less.

[0054] When the ratio of the cross-sectional area of ​​the reinforcing material (reinforcing cord) to the belt reinforcement layer is within a predetermined range, the reason why the aforementioned effects are obtained is not entirely clear, but it is presumed that they are achieved through the following mechanism. By increasing the cross-sectional area ratio of the reinforcing material (reinforcing cord) above the lower limit, the density of the reinforcing material within the reinforcing layer increases, thereby increasing the restraining force and ensuring durability during high-speed driving. Conversely, by keeping it below the upper limit, stress concentration in the rubber covering between the reinforcing materials is suppressed, which is presumed to significantly improve durability during high-speed driving.

[0055] The number of reinforcing members (ends) can be determined by measuring the number of reinforcing members arranged within a range of ±50 mm from the equatorial plane in the tire width direction, with the width of the bead portion aligned to the normal rim width in the radial cross-section of the tire, and calculating the number of members per 50 mm. Furthermore, the cross-sectional area ratio of the reinforcing material 16 can be calculated by determining the thickness S (mm) of the belt reinforcement layer on the equatorial plane, with the width between the bead portions fixed to match the normal rim width in a cross-sectional section cut radially from the tire, and then performing the following calculation. Area ratio = (Ends × Cross-sectional area of ​​the code) / (S × 50) × 100

[0056] Furthermore, from the viewpoint of ensuring good adhesion to the covering rubber layer, it is preferable that the reinforcing material 16 is pre-treated with an adhesive layer. Known adhesive layers can be used, for example, treatment with resorcinol-formaldehyde-rubber latex (RFL), epoxy treatment with an adhesive composition containing sorbitol polyglycidyl ether and blocked isocyanate followed by RFL treatment, or treatment with an adhesive composition containing a halohydrin compound, a blocked isocyanate compound and rubber latex.

[0057] Resorcinol-formaldehyde-rubber latex (RFL) is, for example, an adhesive composition containing natural rubber and / or synthetic rubber latex and a cocondensate of phenol-formaldehyde and resorcinol, as described in Japanese Patent Publication No. 48-11335. Such an adhesive composition can be produced, for example, by a manufacturing method that includes the steps of condensing phenol and formaldehyde in the presence of an alkaline catalyst, copolymerizing an aqueous phenol-formaldehyde resin solution with resorcinol, and mixing the resulting phenol-formaldehyde-resorcinol resin solution with latex rubber.

[0058] Examples of synthetic rubber latex include butadiene polymer latex, styrene / butadiene copolymer latex, isoprene polymer latex, butadiene / acrylonitrile copolymer latex, butadiene / vinylpyridine polymer latex, and butadiene / vinylpyridine / styrene copolymer latex.

[0059] The adhesive layer consisting of the above-mentioned resorcinol-formaldehyde-rubber latex (RFL) can be formed by applying RFL adhesive (such as by dipping the reinforcing material 16 in RFL solution). The RFL adhesive is usually applied after twisting to obtain a fiber cord, but it may also be applied before or during twisting.

[0060] The composition of the above RFL adhesive is not particularly limited and may be selected as appropriate, but it is preferably a composition containing 0.1 to 10% by mass of resorcinol, 0.1 to 10% by mass of formalin, and 1 to 28% by mass of latex, and more preferably a composition containing 0.5 to 3% by mass of resorcinol, 0.5 to 3% by mass of formalin, and 10 to 25% by mass of latex.

[0061] Examples of heating methods in the heat treatment include drying the reinforcing material 16 to which the RFL adhesive composition is attached at 100-250°C for 1-5 minutes, and then further heat-treating it at 150-250°C for 1-5 minutes. The conditions for the heat treatment after drying are preferably 180-240°C for 1-2 minutes.

[0062] The adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate is not particularly limited as long as it contains sorbitol polyglycidyl ether and blocked isocyanate. In particular, a composition containing an epoxy compound of sorbitol polyglycidyl ether having a chlorine content of 9.6% by mass or less and a blocked isocyanate is preferred.

[0063] Examples of sorbitol polyglycidyl ethers include sorbitol diglycidyl ether, sorbitol triglycidyl ether, sorbitol tetraglycidyl ether, sorbitol pentaglycidyl ether, sorbitol hexaglycidyl ether, or mixtures thereof, and may also include sorbitol monoglycidyl ether. Sorbitol polyglycidyl ether has a large number of epoxy groups in one molecule and can form a highly cross-linked structure.

[0064] The chlorine content of sorbitol polyglycidyl ether is preferably 9.6% by mass or less, more preferably 9.5% by mass or less, even more preferably 9.4% by mass or less, and particularly preferably 9.3% by mass or less. The lower limit of the chlorine content is not particularly limited, and is, for example, 1% by mass or more. In this disclosure, the chlorine content of sorbitol polyglycidyl ether can be determined by methods such as those described in JIS K 7243-3.

[0065] The chlorine content of sorbitol polyglycidyl ether can be reduced by reducing the amount of epichlorohydrin used in the synthesis of epoxy compounds, among other things.

[0066] Blocked isocyanates are compounds produced by the reaction of an isocyanate compound with a blocking agent, and are temporarily inactivated by a group derived from the blocking agent. When heated at a predetermined temperature, the group derived from the blocking agent dissociates, generating an isocyanate group.

[0067] Examples of isocyanate compounds include those having two or more isocyanate groups in their molecule. Examples of diisocyanates having two isocyanate groups include hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, tolylene diisocyanate, trimethylhexamethylene diisocyanate, metaphenylene diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, diphenylpropane diisocyanate, biphenyl diisocyanate, and their isomers, alkyl-substituted compounds, halides, hydrogenated compounds to the benzene ring, etc. In addition, triisocyanates having three isocyanate groups, tetraisocyanates having four isocyanate groups, and polymethylene polyphenyl polyisocyanate, etc. These isocyanate compounds can be used individually or in combination of two or more. Among these, tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate are preferred.

[0068] Examples of blocking agents include lactam-based agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; phenol-based agents such as phenol, cresol, resorcinol, and xylenol; alcohol-based agents such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and benzyl alcohol; oxime-based agents such as formamidexime, acetaldehydexime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexanone oxime; and active methylene-based agents such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone. Among these, lactam-based, phenol-based, and oxime-based blocking agents are preferred.

[0069] In the adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate, the content of the blocked isocyanate is preferably 50 parts by mass or more, more preferably 200 parts by mass or more, per 100 parts by mass of sorbitol polyglycidyl ether. The upper limit is preferably 500 parts by mass or less, more preferably 400 parts by mass or less.

[0070] The adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate may optionally contain the following components: for example, epoxy compounds other than sorbitol polyglycidyl ether, resins copolymerizable with sorbitol polyglycidyl ether, curing agents other than blocked isocyanates, organic thickeners, antioxidants, light stabilizers, adhesion enhancers, reinforcing agents, softeners, colorants, leveling agents, flame retardants, and antistatic agents.

[0071] Examples of epoxy compounds other than sorbitol polyglycidyl ether include glycidyl ethers such as ethylene glycol glycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, novolac glycidyl ether, and brominated bisphenol A diglycidyl ether; glycidyl esters such as hexahydrophthalate glycidyl ester and dimer acid glycidyl ester; triglycerides Examples include glycidylamines such as glycidyl isocyanurate, glycidylhindantoin, tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmetaaminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylmetaxylenediamine, diglycidyltribromaniline, and tetraglycidylbisaminomethylcyclohexane; and alicyclic or aliphatic epoxides such as 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, and epoxidized soybean oil.

[0072] Treatment with the adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate includes treatments performed to adhere the various components contained in RFL to the reinforcing material 16, and, if necessary, subsequent heat treatments.

[0073] Any method of application can be used, such as coating with a roller, spraying from a nozzle, or immersion in a bath solution (adhesive composition). From the viewpoint of uniform application and removal of excess adhesive, application by immersion is preferred.

[0074] Furthermore, in order to adjust the amount of material adhering to the reinforcing material 16, means such as squeezing with a pressure roller, scraping with a scraper, blowing away with compressed air, suction, and beating with a beater may be employed.

[0075] The amount adhering to the reinforcing material 16 is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and also preferably 3.0% by mass or less, more preferably 2.5% by mass or less. The amount of adhesive adhering to the reinforcing material 16 is the amount of solid content in the RFL adhesive adhering to 100 parts by mass of the reinforcing material 16.

[0076] The total solid content concentration of the adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate is preferably 0.9% by mass or more, more preferably 14% by mass or more, and also preferably 29% by mass or less, more preferably 23% by mass or less.

[0077] In addition to resorcinol, formalin, and rubber latex, the adhesive composition containing the above-mentioned sorbitol polyglycidyl ether and blocked isocyanate may also contain vulcanization modifiers, zinc oxide, antioxidants, defoaming agents, etc.

[0078] Examples of heating methods in the heat treatment include drying the reinforcing material 16 to which the RFL adhesive composition is attached at 100-250°C for 1-5 minutes, and then further heat-treating it at 150-250°C for 1-5 minutes. The conditions for the heat treatment after drying are preferably 180-240°C for 1-2 minutes.

[0079] The adhesive composition containing the above-mentioned halohydrin compound, blocked isocyanate compound, and rubber latex is not particularly limited as long as it contains these components, but an adhesive composition containing the halohydrin compound, blocked isocyanate compound, and rubber latex, and not containing resorcinol and formaldehyde, is preferred.

[0080] Examples of halohydrin compounds include compounds obtained by reacting polyol compounds with epihalohydrin compounds (halohydrin ethers). Polyol compounds are compounds that have two or more hydroxyl groups in their molecule. Examples include glycols such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; hydroxyl acids such as erythritol, xylitol, sorbitol, and tartaric acid; glyceric acid, glycerin, diglycerin, polyglycerin, trimethylolpropane, trimethylolethane, and pentaerythritol. Examples of epihalohydrin compounds include epichlorohydrin and epibromohydrin.

[0081] Examples of halohydrin compounds include fluoroalcohol compounds, chlorohydrin compounds, bromohydrin compounds, and iodohydrin compounds. Among these, halogenated sorbitol and halogenated glycerol are preferred.

[0082] The halogen content in 100% by mass of the halohydrin compound is preferably 5.0 to 15.0% by mass, more preferably 7.0 to 13.0% by mass, and even more preferably 9.0 to 12.0% by mass.

[0083] Examples of blocked isocyanate compounds include those similar to the blocked isocyanates mentioned above. Similarly, examples of rubber latex include those similar to the rubber latex mentioned above.

[0084] The adhesive composition containing the above-mentioned halohydrin compound, blocked isocyanate compound, and rubber latex preferably contains 10.0 to 30.0 parts by mass of the halohydrin compound, 10.0 to 30.0 parts by mass of the blocked isocyanate compound, and 80.0 to 240.0 parts by mass of rubber latex. Furthermore, the adhesive composition does not contain resorcinol or formaldehyde.

[0085] An adhesive layer comprising an adhesive composition containing the above-mentioned halohydrin compound, blocked isocyanate compound, and rubber latex is formed on the surface of the reinforcing material 16 using the adhesive composition. The adhesive layer is formed by, but is not limited to, dipping, brushing, casting, spraying, roll coating, knife coating, etc.

[0086] In the belt reinforcement layer 15, the covering rubber composition for the belt reinforcement layer (reinforcement rubber 17) that covers the reinforcing cord 16 contains a rubber component.

[0087] In a coating rubber composition for belt reinforcement layers, the rubber component is a component that contributes to crosslinking, and is generally a polymer with a weight-average molecular weight (Mw) of 10,000 or more, and the polymer component that is not extracted by acetone corresponds to the rubber component. The rubber component is in a solid state at room temperature (25°C).

[0088] The weight-average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and also preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within this range, a better effect tends to be obtained.

[0089] In this specification, the weight-average molecular weight (Mw) can be determined by converting the measured values ​​obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation) to standard polystyrene equivalents.

[0090] For example, diene-based rubbers can be used as rubber components for the belt reinforcement layer coating rubber composition. Examples of diene-based rubbers include isoprene-based rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). Butyl-based rubbers and fluororubbers can also be used. These may be used individually or in combination of two or more. Among these, isoprene-based rubber, BR, and SBR are preferred, with isoprene-based rubber being more preferred, from the viewpoint of obtaining better effects. Furthermore, these rubber components may undergo modification treatment and hydrogenation treatment as described later, and stretched rubber, which has been stretched with oil, resin, liquid rubber components, etc., may also be used.

[0091] The above diene rubber may be either unmodified diene rubber or modified diene rubber. Modified diene rubbers can be any diene rubber having a functional group that interacts with a filler such as silica. Examples include end-modified diene rubbers (end-modified diene rubbers having the functional group at the end) in which at least one end of the diene rubber is modified with a compound (modifier) ​​having the functional group, main-chain modified diene rubbers having the functional group in the main chain, main-chain end-modified diene rubbers having the functional group in both the main chain and the end (for example, main-chain end-modified diene rubbers having the functional group in the main chain and at least one end modified with the modifier), and end-modified diene rubbers that are modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and in which hydroxyl groups or epoxy groups are introduced.

[0092] Examples of the above functional groups include amino groups, amide groups, silyl groups, alkoxysilyl groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, thiocarbonyl groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, and the like. These functional groups may have substituents. Among these, amino groups (preferably amino groups in which the hydrogen atoms of the amino group are substituted with C1-C6 alkyl groups), alkoxy groups (preferably alkoxy groups having C1-C6), and alkoxysilyl groups (preferably alkoxysilyl groups having C1-C6) are preferred.

[0093] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. For NR, common types used in the rubber industry can be used, such as SIR20, RSS#3, and TSR20. For IR, there are no particular limitations; common types used in the rubber industry can be used, such as IR2200. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used individually or in combination of two or more types.

[0094] In the coating rubber composition for belt reinforcement layers, the content of isoprene-based rubber in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 50% by mass or more, even more preferably 75% by mass or more, and particularly preferably 85% by mass or more, and may be 100% by mass. When the content is within the above range, a better effect tends to be obtained.

[0095] BR is not particularly limited, and for example, high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare-earth catalyst (rare-earth BR) can be used. These may be used individually or in combination of two or more. In particular, it is preferable that the BR contains high-cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. The cis content can be measured by infrared absorption spectroscopy.

[0096] Furthermore, both unmodified and modified BR can be used. Modified BR includes BR in which functional groups similar to those of modified diene rubber have been introduced. Hydrogenated butadiene polymers (hydrogenated BR) can also be used.

[0097] For example, products from companies such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used as BRs.

[0098] When the coating rubber composition for the belt reinforcement layer contains BR, the BR content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. Within the above range, a better effect tends to be obtained.

[0099] The SBR is not particularly limited; for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc., can be used. These may be used individually or in combination of two or more types.

[0100] The styrene content of SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The styrene content is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. Keeping it within the above range tends to improve handling stability during high-speed driving. In this specification, the styrene content is defined as follows: 1 It can be measured by 1H-NMR.

[0101] The vinyl bonding amount of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The vinyl bonding amount is preferably 25% by mass or less, more preferably 15% by mass or less, and even more preferably 13% by mass or less. Keeping it within the above range tends to improve handling stability during high-speed driving. In this specification, the amount of vinyl bond (amount of 1,2-bonded butadiene units) can be measured by infrared absorption spectroscopy.

[0102] Both unmodified and modified SBR can be used. Modified SBR includes SBR with functional groups similar to those introduced in modified diene rubber. Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

[0103] For example, SBR manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Co., Ltd. can be used.

[0104] When the coating rubber composition for the belt reinforcement layer contains SBR, the SBR content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. Within the above range, a better effect tends to be obtained.

[0105] The rubber coating composition for the belt reinforcement layer may contain fillers. The filler is not particularly limited and any material known in the rubber field can be used, such as inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica; and poorly dispersible fillers.

[0106] In the rubber composition for covering the belt reinforcing layer, the total filler content (total amount of fillers such as silica and carbon black) is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more with respect to 100 parts by mass of the rubber component. The upper limit of the content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, still more preferably 80 parts by mass or less. When within the above range, the effect tends to be obtained more favorably.

[0107] Among the fillers (filler materials), carbon-derived fillers (carbon-containing fillers) such as carbon black and silica are preferred.

[0108] The carbon black that can be used in the rubber composition for covering the belt reinforcing layer is not particularly limited, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nippon Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. These may be used alone or in combination of two or more. In addition to carbon black made from conventional mineral oil or the like as a raw material, carbon black made from biomass materials such as lignin may also be used.

[0109] The nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 30 m 2 [[ID=IS16]] / g or more, more preferably 50 m 2 / g or more, still more preferably 70 m 2 / g or more. Also, the above N2SA is preferably 200 m 2 / g or less, more preferably 150 m 2 / g or less, still more preferably 2 2 130 m 2 / g or less, and particularly preferably 120 m<00000l1> / g or less. When within the above range, the effect tends to be obtained more favorably.

[0110] When the coating rubber composition for the belt reinforcement layer contains carbon black, the carbon black content is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit of the content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0111] Suitable silica types include dry-process silica (anhydrous silica) and wet-process silica (hydrated silica). Wet-process silica is preferred due to its higher silanol group content. Commercially available products include those from Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama Corporation. These can be used individually or in combination of two or more types. In addition to these silicas, silica derived from biomass materials such as rice husks may also be used.

[0112] The nitrogen adsorption specific surface area (N2SA) of silica is preferably 50 m². 2 / g or more, comfortably 100m 2 / g or more, more preferably 150m 2 / g or more, particularly preferably 180m 2 / g or more, most preferably 190m 2 It is 1 / g or more. Furthermore, the upper limit of N2SA in silica is not particularly limited, but preferably 350m 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2 It is less than or equal to / g. Within the above range, there is a tendency for better results to be obtained. Note that the N2SA value of silica is measured by the BET method in accordance with ASTM D3037-93.

[0113] When the coating rubber composition for the belt reinforcement layer contains silica, the silica content is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit of the content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0114] If the coating rubber composition for the belt reinforcement layer contains silica, it is preferable that it further contains a silane coupling agent. The silane coupling agent is not particularly limited and any known in the rubber field can be used, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl) trisulfide, bis(4-trimethoxysilylbutyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, Examples include sulfide-based compounds such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products from companies such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. can be used. These can be used individually or in combination of two or more types.

[0115] In the coating rubber composition for belt reinforcement layers, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more, per 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0116] Examples of poorly dispersible fillers include microfibrillated plant fibers, short fibrous cellulose, and gel-like compounds. Among these, microfibrillated plant fibers are preferred.

[0117] As the above-mentioned microfibrillated plant fiber, cellulose microfibrils are preferred in that they provide good reinforcing properties. The cellulose microfibrils are not particularly limited as long as they are derived from natural products, and examples include resource biomass such as fruits, grains, and root vegetables; wood, bamboo, hemp, jute, and kenaf, as well as waste biomass such as pulp, paper, cloth, agricultural residues, food waste, and sewage sludge obtained from these raw materials, unused biomass such as rice straw, wheat straw, and thinned wood, and cellulose produced by sea squirts, acetic acid bacteria, etc. One type of these microfibrillated plant fiber may be used, or two or more types may be used in combination.

[0118] In this specification, cellulose microfibrils typically refer to cellulose fibers having an average fiber diameter of 10 μm or less, and more typically, cellulose fibers having a microstructure with an average fiber diameter of 500 nm or less, formed by an aggregate of cellulose molecules. Typical cellulose microfibrils are formed, for example, as aggregates of cellulose fibers having the average fiber diameter described above.

[0119] In a coating rubber composition for belt reinforcement layers, the content of poorly dispersible filler is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0120] A plasticizer may be added to the rubber coating composition for the belt reinforcement layer. Plasticizers are materials that impart plasticity to rubber components. Examples include liquid plasticizers (plasticizers that are liquid at room temperature (25°C)) and resins (resins that are solid at room temperature (25°C)).

[0121] In the coating rubber composition for belt reinforcement layers, the plasticizer content (total amount of plasticizer) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less, per 100 parts by mass of rubber component, and may be 0 parts by mass. Within the above range, a better effect tends to be obtained. Note that when the aforementioned stretchable rubber is used, the amount of stretchable component used in that stretchable rubber is included in the plasticizer content.

[0122] The liquid plasticizer (a plasticizer that is in a liquid state at room temperature (25°C)) that can be used in the coating rubber composition for the belt reinforcement layer is not particularly limited, and examples include oils and liquid polymers (liquid resins, liquid diene polymers, etc.). These may be used alone or in combination of two or more.

[0123] In the coating rubber composition for belt reinforcement layers, the liquid plasticizer content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less, per 100 parts by mass of rubber component, and may be 0 parts by mass. Within the above range, a better effect tends to be obtained. The oil content is also preferably within a similar range.

[0124] Examples of oils include process oils, vegetable oils, or mixtures thereof. Examples of process oils include paraffinic process oils such as MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (treated Distillate Aromatic Extract), TRAE (treated Residual Aromatic Extract), and RAE (residual Aromatic Extract), as well as aromatic process oils and naphthenic process oils. Examples of vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice bran oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. Commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., and Nisshin Oillio Group, Ltd. are suitable. Process oils (paraffinic process oils, aromatic process oils, naphthenic process oils, etc.) and vegetable oils are particularly preferred. Furthermore, from a life cycle assessment perspective, lubricating oils used in rubber mixers and engines, or refined waste cooking oils used in restaurants, may also be used as the oils mentioned above.

[0125] Examples of liquid resins include terpene resins (including terpene phenol resins and aromatically modified terpene resins), rosin resins, styrene resins, C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, coumarone-indene resins (including coumarone and indene-only resins), phenolic resins, olefin resins, polyurethane resins, and acrylic resins. Hydrogenated versions of these resins can also be used.

[0126] Examples of liquid diene polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer), liquid farnesene polymer, and liquid farnesene-butadiene copolymer. These polymers may have polar groups attached to their ends or main chains. Hydrogenated versions of these polymers can also be used.

[0127] Examples of resins (resins that are solid at room temperature (25°C)) that can be used in the coating rubber composition for the belt reinforcement layer include aromatic vinyl polymers, coumarone indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins, all of which are solid at room temperature (25°C). The resins may also be hydrogenated. These may be used individually or in combination of two or more. Among these, aromatic vinyl polymers, petroleum resins, and terpene resins are preferred.

[0128] When the coating rubber composition for the belt reinforcement layer contains the above resin, the amount of the resin is preferably 100 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less, per 100 parts by mass of the rubber component, and may even be 0 parts by mass. Within the above range, a better effect tends to be obtained.

[0129] The softening point of the above resin is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher. The upper limit is preferably 160°C or lower, more preferably 130°C or lower, and even more preferably 115°C or lower. Keeping it within the above range tends to improve handling stability during high-speed driving. The softening point of the above resin is determined by measuring the softening point as specified in JIS K6220-1:2001 using a ring-type softening point measuring device, and it is the temperature at which the sphere descends. The softening point of the above resin is usually 50°C ± 5°C higher than the glass transition temperature of the resin.

[0130] The above-mentioned aromatic vinyl polymer is a polymer containing aromatic vinyl monomers as constituent units. Examples include resins obtained by polymerizing α-methylstyrene and / or styrene, specifically, homopolymers of styrene (styrene resin), homopolymers of α-methylstyrene (α-methylstyrene resin), copolymers of α-methylstyrene and styrene, copolymers of styrene and other monomers.

[0131] The above-mentioned coumarone-indene resin is a resin that contains coumarone and indene as the main monomer components that constitute the resin's backbone (main chain). Other monomer components that may be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0132] The coumarone resin described above is a resin that contains coumarone as the main monomer component that constitutes the resin's backbone (main chain).

[0133] The above-mentioned indene resin is a resin that contains indene as the main monomer component that constitutes the resin's backbone (main chain).

[0134] As the phenolic resin mentioned above, known polymers such as those obtained by reacting phenol with aldehydes such as formaldehyde, acetaldehyde, and furfural using an acid or alkali catalyst can be used. Among these, those obtained by reaction with an acid catalyst (such as novolac-type phenolic resins) are preferred.

[0135] Examples of the rosin resins mentioned above include natural rosin, polymerized rosin, modified rosin, their ester compounds, and rosin-based resins represented by their hydrogenated products.

[0136] Examples of the above petroleum resins include C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, and hydrogenated versions thereof. Among these, DCPD resins and hydrogenated DCPD resins are preferred.

[0137] The above-mentioned terpene resins are polymers containing terpenes as constituent units. Examples include polyterpene resins obtained by polymerizing terpene compounds, and aromatically modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds. Hydrogenated versions of these can also be used.

[0138] The above polyterpene resin is a resin obtained by polymerizing a terpene compound. The terpene compound is (C5H8) n A hydrocarbon and its oxygen-containing derivative represented by the following composition, monoterpene (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpene (C 20 H 32 These are compounds with a terpene as their basic skeleton, classified as such, and examples include α-pinene, β-pinene, dipentene, limonene, myrcene, allocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0139] Examples of the polyterpene resins mentioned above include pinene resin, limonene resin, dipentene resin, and pinene / limonene resin, which are made from the terpene compounds described above. Among these, pinene resin is preferred. Pinene resin usually contains both α-pinene and β-pinene, which are isomers of each other, but depending on the difference in the components it contains, it is classified into β-pinene resin, which has β-pinene as the main component, and α-pinene resin, which has α-pinene as the main component.

[0140] Examples of the above-mentioned aromatically modified terpene resins include terpene-phenol resins made from the above-mentioned terpene compounds and phenolic compounds, and terpene-styrene resins made from the above-mentioned terpene compounds and styreneic compounds. In addition, terpene-phenol-styrene resins made from the above-mentioned terpene compounds, phenolic compounds, and styreneic compounds can also be used. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of styreneic compounds include styrene and α-methylstyrene.

[0141] The above-mentioned acrylic resin is a polymer containing acrylic monomers as constituent units. Examples include styrene-acrylic resins such as styrene-acrylic resin, which have carboxyl groups and are obtained by copolymerizing an aromatic vinyl monomer component with an acrylic monomer component. Among these, solvent-free carboxyl group-containing styrene-acrylic resins can be suitably used.

[0142] The above-mentioned solvent-free carboxyl group-containing styrene-acrylic resin is a (meth)acrylic resin (polymer) synthesized by high-temperature continuous polymerization (high-temperature continuous mass polymerization) (as 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, Toa Gosei Research Annual Report TREND2000 No. 3, pp. 42-45, etc.) with minimal use of polymerization initiators, chain transfer agents, organic solvents, etc. as auxiliary raw materials. In this specification, (meth)acrylic means methacrylic and acrylic.

[0143] Examples of acrylic monomer components constituting the above-mentioned acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters such as 2-ethylhexyl acrylate, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives. Note that (meth)acrylic acid is a general term for acrylic acid and methacrylic acid.

[0144] Examples of aromatic vinyl monomer components that constitute the above-mentioned acrylic resin include aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene.

[0145] In addition, other monomer components may be used as monomer components constituting the above-mentioned acrylic resin, along with (meth)acrylic acid, (meth)acrylic acid derivatives, and aromatic vinyl.

[0146] Examples of plasticizers that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Taoka Chemical Industries, Ltd., and others.

[0147] The rubber coating composition for the belt reinforcement layer preferably contains an anti-aging agent from the viewpoint of crack resistance, ozone resistance, etc.

[0148] While not particularly limited, the following are examples of anti-aging agents: naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and N,N'-di-2-naphthyl-p-phenylenediamine. Examples of anti-aging agents include p-phenylenediamine-based anti-aging agents such as amines; quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercial products such as those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd. can be used.

[0149] In the coating rubber composition for belt reinforcement layers, the content of the anti-aging agent is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 2.0 parts by mass or more, per 100 parts by mass of the rubber component. The content is preferably 7.0 parts by mass or less, and more preferably 4.0 parts by mass or less.

[0150] The rubber composition preferably contains stearic acid. In the coating rubber composition for belt reinforcement layers, the stearic acid content is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0151] In addition, conventionally known stearic acid can be used, such as products from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acid Co., Ltd.

[0152] The rubber coating composition for the belt reinforcement layer preferably contains zinc oxide. In the coating rubber composition for belt reinforcement layers, the zinc oxide content is preferably 0.5 to 10 parts by mass, more preferably 1 to 3 parts by mass, per 100 parts by mass of the rubber component.

[0153] In addition, conventionally known zinc oxides can be used, such as products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd.

[0154] The rubber coating composition for the belt reinforcement layer may contain wax. In the coating rubber composition for belt reinforcement layers, the wax content is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of rubber component.

[0155] The type of wax used is not particularly limited and includes petroleum-based waxes, natural waxes, and synthetic waxes obtained by refining or chemically processing multiple waxes. These waxes may be used individually or in combination of two or more types.

[0156] Examples of petroleum-based waxes include paraffin wax and microcrystalline wax. Examples of natural waxes are not limited to those derived from non-petroleum resources, and include plant-based waxes such as candelilla wax, carnauba wax, wood wax, rice wax, and jojoba wax; animal-based waxes such as beeswax, lanolin, and whale wax; mineral waxes such as ozokerite, ceresin, and petrolactam; and refined products thereof. Commercially available products include those from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0157] It is preferable to incorporate sulfur into the coating rubber composition for the belt reinforcement layer, as this forms appropriate cross-linked chains in the polymer chains and imparts good performance.

[0158] In the coating rubber composition for belt reinforcement layers, the sulfur content is preferably 0.1 parts by mass or more, more preferably 1.0 part by mass or more, and even more preferably 1.7 parts by mass or more, per 100 parts by mass of the rubber component. The content is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less.

[0159] Examples of sulfur commonly used in the rubber industry include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur. Commercially available products include those from Tsurumi Chemical Industries, Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industry Co., Ltd. These can be used individually or in combination of two or more types.

[0160] The rubber coating composition for the belt reinforcement layer preferably contains a vulcanization accelerator. In the coating rubber composition for belt reinforcement layers, there are no particular restrictions on the content of the vulcanization accelerator, and it can be freely determined according to the desired vulcanization rate and crosslinking density. However, it is preferably 0.5 parts by mass or more, more preferably 2.0 parts by mass or more, and even more preferably 2.7 parts by mass or more, per 100 parts by mass of rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, and even more preferably 5.0 parts by mass or less.

[0161] There are no particular restrictions on the type of vulcanization accelerator; commonly used ones can be used. Examples of vulcanization accelerators include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotrilguanidine, and orthotrilbiguanidine. These may be used individually or in combination of two or more. Among them, sulfenamide, guanidine, and benzothiazole vulcanization accelerators are preferred.

[0162] In addition to the components mentioned above, the rubber coating composition for the belt reinforcement layer may also contain other compounding agents commonly used in the tire industry, such as mold release agents.

[0163] In the belt layer coating rubber (topping rubber 10 that covers the belt cord 9) and other components, the same materials as the reinforcing rubber 17 (covering rubber composition for belt reinforcing layer) can be used, with the appropriate amount of material added.

[0164] Furthermore, the reinforcing rubber 17 (covering rubber composition for belt reinforcing layer) may be, for example, a different rubber composition from or the same rubber composition as the topping rubber 10.

[0165] As a method for producing the coating rubber composition for the belt reinforcement layer, known methods can be used. For example, the composition can be produced by kneading each of the components using a rubber kneading device such as an open roll or Banbury mixer, and then vulcanizing it.

[0166] Regarding the mixing conditions, in the base mixing step where additives other than the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 50 to 200°C, preferably 80 to 190°C, and the mixing time is usually 30 seconds to 30 minutes, preferably 1 minute to 30 minutes. In the finish mixing step where the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 100°C or lower, preferably room temperature to 80°C. Furthermore, the composition mixed with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 120 to 200°C, preferably 140 to 180°C.

[0167] Tires to which the belt reinforcement layer 15, which includes a reinforcing material 16 (reinforcing cord) and a reinforcing rubber 17 (covering rubber composition for belt reinforcement layer) that covers the reinforcing cord 16, can be applied include pneumatic tires and non-pneumatic tires, but pneumatic tires are preferred. In particular, it can be suitably used as a summer tire (summer tire) or a winter tire (studless tire, snow tire, stud tire, etc.). The tire can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a heavy load tire for trucks and buses, a light truck tire, a motorcycle tire, a racing tire (high-performance tire), etc.

[0168] The tire is manufactured by conventional methods using a reinforcing material 16 (reinforcing cord) and a reinforcing rubber 17 (covering rubber composition for belt reinforcement layer) that covers the reinforcing cord 16. For example, a rubber composition containing various materials is extruded in the unvulcanized stage, combined with the reinforcing material 16 (reinforcing cord) and the reinforcing rubber 17 (covering rubber composition for belt reinforcement layer) that covers the reinforcing cord 16, to match the shape of the belt reinforcement layer 15, and then molded together with other tire components on a tire molding machine in a conventional manner to form an unvulcanized tire. This unvulcanized tire is then heated and pressurized in a vulcanizing machine to obtain a tire.

[0169] Figure 3 is an enlarged view of the tread section 2. The tire 1 is provided with a belt layer 7 embedded inside the tread portion 2, and a belt reinforcement layer 15 with reinforcing cords 16 on the radially outer side of the belt layer 7, and the tread portion 2 is divided by circumferential main grooves 20.

[0170] In tire 1, the equal cross-sectional area diameter d (mm) of the reinforcing material 16 (reinforcing cord) and the distance L (mm) from the bottom of the tread groove 21 to the belt reinforcing layer 15 satisfy the following formula (2). (2) d / L ≤ 0.80 The d / L is preferably 0.70 or less, more preferably 0.60 or less, even more preferably 0.555 or less, and particularly preferably 0.50 or less. The lower limit is preferably 0.10 or more, more preferably 0.20 or more, even more preferably 0.27 or more, and particularly preferably 0.30 or more. Within the above range, the effect is suitably obtained.

[0171] For tire 1, it is desirable that the distance L (mm) from the bottom of the tread groove 21 to the belt reinforcement layer 15 satisfies the following formula. L≧0.90mm L is preferably 1.00 mm or more, more preferably 1.10 mm or more, even more preferably 1.50 mm or more, and particularly preferably 1.70 mm or more. The upper limit is preferably 2.50 mm or less, more preferably 2.30 mm or less, and even more preferably 2.00 mm or less.

[0172] When the aforementioned distance L is greater than or equal to a predetermined value, particularly when L ≥ 1.00 mm, the reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed that they are achieved through the following mechanism. By setting the distance L to a predetermined level or greater, the distance from the bottom of the groove to the reinforcing material is increased. This makes it more difficult for deformation during rolling to be transmitted to the reinforcing material, thus suppressing the fracture of the reinforcing material. As a result, it is presumed that durability during high-speed driving will be significantly improved.

[0173] In this disclosure, the tread groove bottom 21 refers to the deepest part of the circumferential main groove and the innermost surface in the tire radial direction within the circumferential main groove.

[0174] In this disclosure, the distance L (mm) from the tread groove bottom 21 to the belt reinforcement layer 15 refers to the distance from the tread groove bottom 21 to the radially outer surface 23 of the belt reinforcement layer 15. This distance L is the distance from the groove bottom of the circumferential main groove closest to the tire's equator plane to the radially outer surface of the belt reinforcement layer 15, with the width of the bead portion fixed to match the normal rim width in a cross-sectional section obtained by cutting the tire radially, and is a value measured along the normal to the radially outer surface of the belt reinforcement layer 15.

[0175] In this specification, unless otherwise specified, the dimensions of the tire (such as the distance L from the bottom of the tread groove to the belt reinforcement layer) and angles are measured in a cross-sectional section cut radially from the tire, with the width between the bead portions of the tire fixed to match the normal rim width during measurement. Furthermore, when measuring the angles that the cords in the belt layer 7 and belt reinforcement layer 15 make with respect to the tire's circumferential direction, it is possible to confirm these angles by peeling off the tread portion of the cross-sectional section and observing it from the radial direction of the tire.

[0176] The uniform cross-sectional area diameter d of the reinforcing material (reinforcing cord), the distance L from the bottom of the tread groove to the belt reinforcement layer, the number of reinforcing cords driven in per 50 mm width (ends), and the ratio of the cross-sectional area of ​​the reinforcing material (reinforcing cord) to the belt reinforcement layer per 50 mm width (the ratio of the belt reinforcement layer to 100% of the cross-sectional area) can be similarly measured in cross-sectional sections obtained by cutting the tire radially, unless otherwise specified.

[0177] Although particularly preferred embodiments of this disclosure have been described in detail above, the present invention is not limited to the illustrated embodiments and can be implemented in various modified forms. [Examples]

[0178] The following examples (implementations) are considered preferable for implementation, but the scope of this disclosure is not limited to these examples.

[0179] A pneumatic passenger car tire (test tire) of size 195 / 65R15 with the basic structure shown in Figure 1 will be prototyped based on the specifications in each table (cord material, equal cross-sectional area diameter d of the reinforcing cords, distance L from the bottom of the tread groove to the belt reinforcement layer, etc.). The common specifications for the test tires are as follows: Belt ply: 2 pieces Angle of the belt cord relative to the tire circumference: 20 degrees (crossing) Belt cord: Single wire Ends of belt cord: 36 Belt cord diameter: 0.32mm

[0180] The results calculated based on the evaluation method described below, assuming test tires with specifications changed according to each table, are shown in each table. Comparative Example 7 will be used as the baseline comparative example.

[0181] <Durability at high speeds> The above test tires were mounted on a drum testing machine, and the rotation speed was gradually increased from 100 km / h. The speed at which failure occurred was measured, and the result was expressed as an index with the reference comparison example set to 100 (high-speed durability index). A higher index indicates a higher speed at which failure occurs and superior durability at high speeds.

[0182] [Table 1]

[0183] [Table 2]

[0184] (1) This disclosure relates to a tire having a tread portion and a belt reinforcement layer, The belt reinforcement layer includes a reinforcing material made of a compound represented by the following formula (1): [ka] (In the formula, m is 2 or 3, and n is an integer.) The tire is one in which the uniform cross-sectional area diameter d (mm) of the reinforcing material and the distance L (mm) from the bottom of the tread groove to the belt reinforcing layer satisfy the following formula (2). (2) d / L ≤ 0.80

[0185] Disclosure (2) is the tire according to Disclosure (1) in which the above d (mm) satisfies the following formula. 0.20mm <d<1.00mm

[0186] Disclosure (3) is a tire according to Disclosure (1) or (2) wherein the distance L (mm) satisfies the following formula. L≧1.00mm

[0187] (4) The present disclosure is a tire according to any one of the present disclosures (1) to (3), wherein the reinforcing material is formed from a cord with a twist count of 10.0 to 60.0 (t / 10cm).

[0188] (5) The present disclosure is a tire according to any one of the present disclosures (1) to (4), wherein the reinforcing material is formed from a cord with a total fineness of 500 to 5000 dtex.

[0189] Disclosure (6) is a tire according to any of Disclosures (1) to (5), wherein the number of reinforcing members driven in per 50 mm width (ends) is 30 to 80.

[0190] Disclosure (7) is a tire according to any of Disclosures (1) to (6), wherein the ratio (%) of the cross-sectional area of ​​the reinforcing material to the belt reinforcing layer per 50 mm width is 15 to 55%. [Explanation of Symbols]

[0191] 1 tire 2 Tread section 4. Bead section 6 Carcass 7 Belt layer 8 Belt ply 8A First Belt Ply 8B 2nd Belt Ply 9 Belt cord 10 Topping Rubber 15 Belt reinforcement layer 16. Reinforcement material (reinforcement cord) 17 Reinforcement rubber 20 Circumferential main groove 21 Tread groove bottom 23 Tire radial outer surface W1 First Belt Ply 8A Tire Axial Width W2 2nd Belt Ply 8B Tire Axial Width TW Tread width Te tread edge L Distance from tread groove bottom 21 to belt reinforcement layer 15

Claims

1. A tire having a tread portion and a belt reinforcement layer, The belt reinforcing layer includes a reinforcing material made of a compound represented by the following formula (1): 【Chemistry 1】 (In the formula, m is 2 or 3, and n is an integer.) The uniform cross-sectional area diameter d (mm) of the reinforcing material and the distance L (mm) from the bottom of the tread groove to the belt reinforcing layer satisfy the following formula (2): (2) d / L≦0.80 A tire in which the ratio (%) of the cross-sectional area of ​​the reinforcing material to the belt reinforcement layer per 50 mm width is 15 to 55%.

2. A tire having a tread section and a belt reinforcement layer, The belt reinforcing layer includes a reinforcing material made of a compound represented by the following formula (1): 【Chemistry 2】 (In the formula, m is 2, and n is an integer.) A tire in which the uniform cross-sectional area diameter d (mm) of the reinforcing material and the distance L (mm) from the bottom of the tread groove to the belt reinforcing layer satisfy the following formula (2). (2) d / L≦0.80

3. The tire according to claim 1 or 2, wherein the aforementioned d (mm) satisfies the following formula. 0.20mm<d<1.00mm

4. The tire according to claim 1 or 2, wherein the distance L (mm) satisfies the following formula. L ≥ 1.00 mm

5. The tire according to claim 1 or 2, wherein the reinforcing material is formed from a cord with a twist count of 10.0 to 60.0 (t / 10cm).

6. The tire according to claim 1 or 2, wherein the reinforcing material is formed from a cord with a total fineness of 500 to 5000 dtex.

7. The tire according to claim 1 or 2, wherein the number of reinforcing members driven in per 50 mm width (ends) is 30 to 80.

8. The tire according to claim 2, wherein the ratio (%) of the cross-sectional area of ​​the reinforcing material to the belt reinforcing layer per 50 mm width is 15 to 55%.

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