Pneumatic tire

Abstract

Provided is a pneumatic tire in which low rolling resistance during high-speed travel is improved and deterioration of handling stability during high-speed travel is further suppressed. The pneumatic tire has a tread portion and a belt layer, and the reinforcing cords in the belt layer are composed of monofilament cords arranged at 50 or more per 5 cm in the tire width direction in a tire radial cross section of the belt layer. The tire cross-sectional width wt (mm) and the outer diameter Dt (mm) when mounted on a standard rim and inflated to an internal pressure of 250 kPa satisfy the following (Formula 1): 1500 ≦ (Dt 2 × π / 4) / Wt (Formula 1).

Description

Technical Field

[0001] This disclosure relates to a pneumatic tire, and more specifically to a pneumatic tire having a belt layer. Background Technology

[0002] In recent years, due to increasing concerns about environmental issues and considerations of economic efficiency, there is a strong need to reduce fuel consumption in motor vehicles and improve the fuel efficiency of pneumatic tires (hereinafter referred to as "tires") installed in motor vehicles.

[0003] Tire fuel efficiency can be evaluated by rolling resistance; it is known that the lower the rolling resistance, the better the tire's fuel efficiency.

[0004] Therefore, it has been proposed in the past to reduce rolling resistance by designing the formulation of the rubber composition constituting the tread of the tire (e.g., Patent Documents 1 to 4). [Existing Technical Documents] [Patent Literature]

[0005] Patent Document 1: JP 2018-178034 A Patent Document 2: JP 2019-089911 A Patent Document 3: WO 2018 / 186367 A Patent Document 4: JP 2019-206643 A Summary of the Invention [The problem this invention aims to solve]

[0006] However, with the development of highways in recent years, the opportunities for long-distance driving at high speeds have increased dramatically. In this context, it cannot be said that the aforementioned traditional technologies are sufficient to improve low rolling resistance at high speeds. Furthermore, there is also the problem of deteriorated handling stability.

[0007] Therefore, the purpose of this disclosure is to provide a pneumatic tire that further improves low rolling resistance at high speeds and further suppresses deterioration in handling stability at high speeds. [Methods used to solve problems]

[0008] The inventors have conducted in-depth research on how to solve the above problems and have found that the above problems can be solved by the disclosure described below, and have completed this disclosure.

[0009] This disclosure is as follows: A pneumatic tire having a tread and a belt layer, wherein, The reinforcing cords in the belt layer are composed of monofilament cords, which are arranged at least 50 cords per 5cm in the tire's radial cross-section along the tire width direction; and When the tire is mounted on a standard rim and the internal pressure is 250 kPa, the tire's cross-sectional width Wt (mm) and outer diameter Dt (mm) satisfy the following (Equation 1): 1500≦(Dt 2 ×π / 4) / Wt(Equation 1). [Invention Effects]

[0010] According to this disclosure, a pneumatic tire that further improves low rolling resistance at high speeds and further suppresses deterioration in handling stability at high speeds can be provided. Detailed Implementation

[0011] [1] Features of the tires disclosed herein First, the characteristics of the tire disclosed herein will be described.

[0012] 1. Overview The tire disclosed herein is a tire having a belt layer, wherein the reinforcing cords in the belt layer are composed of monofilament cords, and the monofilament cords are arranged at a rate of 50 cords / 5cm or more in the tire width direction in the radial cross section of the belt layer.

[0013] Furthermore, when the tire of the present invention is mounted on a standard rim and the internal pressure is 250 kPa, the tire's cross-sectional width Wt (mm) and outer diameter Dt (mm) satisfy the following (Equation 1): 1500≦(Dt 2 ×π / 4) / Wt(Equation 1).

[0014] By incorporating these features (as described below), a pneumatic tire can be provided that further improves low rolling resistance at high speeds and further suppresses deterioration in handling stability at high speeds.

[0015] In this article, the term "standard rim" refers to the rim specified for each type of tire within a standards system that includes the standards upon which the tire is based. For example, in the case of JATMA (Japan Automobile Tire Manufacturers Association), the standard rim in the applicable size listed in the "JATMA YEAR BOOK"; in the case of ETRTO (The European Tire and Rim Technical Organization), the "Measuring Rim" listed in the "STANDARDS MANUAL"; and in the case of TRA (The Tire and Rim Association, Inc.), the "Design Rim" (referring to "regular rim") listed in the "YEAR BOOK". In the case of tires not specified in the standards, it refers to the rim with the smallest diameter and thus the narrowest width among rims that can be assembled and maintain internal pressure (i.e., rims that do not leak air between the rim and the tire).

[0016] In the above description, the tire's outer diameter Dt is the outer diameter of the tire when it is mounted on a standard rim, the internal pressure is set to 250 kPa, and no load is applied. The tire's cross-sectional width Wt is the straight-line distance between tire sidewalls obtained by subtracting all patterns, characters, etc. on the tire sidewalls from the total tire width (including all patterns, characters, etc.) when the tire is mounted on a standard rim, the internal pressure is set to 250 kPa, and no load is applied.

[0017] 2. The mechanism by which the tire of this disclosure performs its function The mechanism by which the tire of this disclosure performs its effect (i.e., the mechanism of further improving low rolling resistance at high speeds and further suppressing the deterioration of handling stability at high speeds) is speculated as follows.

[0018] As described above, in this disclosure, the tire's cross-sectional width Wt (mm) and outer diameter Dt (mm) satisfy 1500 ≤ (Dt) / 2. 2 ×π / 4) / Wt(Equation 1).

[0019] It is believed that increasing the tire's area when viewed laterally [(Dt / 2)] can help. 2 ×π)=(Dt 2The ratio of [×π / 4] to the tire's cross-sectional width Wt (specifically, by increasing this ratio to over 1500) can increase the tire's moment of inertia and reduce rolling resistance in steady state. The above (Dt) 2 The value of ×π / 4) / Wt is more preferably 1541 or higher, even more preferably 1544 or higher, even more preferably 1546 or higher, even more preferably 1549 or higher, even more preferably 1554 or higher, even more preferably 1600 or higher, even more preferably 1660 or higher, even more preferably 1662 or higher, even more preferably 1666 or higher, even more preferably 1671 or higher, even more preferably 1700 or higher, even more preferably 1748 or higher, even more preferably 1800 or higher, even more preferably 1963.4 or higher, even more preferably 2075 or higher.

[0020] However, the centrifugal force of such tires tends to increase, and the tread can deform into a round shape at high speeds, leading to worsened rolling resistance. Furthermore, at high speeds, as the centrifugal force increases, the outer diameter tends to increase, which can result in reduced handling stability.

[0021] Therefore, in this disclosure, in the belt layer constraining the tread, cords made of monofilaments (monofilament cords) are used instead of cords made of twisted yarns (twisted cords) as reinforcing cords. Since monofilament cords are not twisted, they are less prone to elongation and deformation, thus exhibiting excellent restraining properties. It is believed that by employing a belt layer in which such monofilament cords are densely arranged at a density of 50 cords / 5cm or more (i.e., with a spacing of less than 1mm between each cord), the tread is sufficiently constrained during high-speed driving, thereby effectively suppressing tread deformation caused by centrifugal force and improving low rolling resistance.

[0022] Furthermore, when such belt layers are used, the deformation of the tread profile is reduced, and the responsiveness to shear deformation of the belt layers is improved. Therefore, it is believed that this can improve handling stability at high speeds and suppress the deterioration of handling stability at high speeds.

[0023] The outer diameter of the monofilament cord is preferably 0.1 mm or more and 0.5 mm or less. More preferably, it is 0.25 mm or more and 0.40 mm or less. If the outer diameter of the cord is too small, even if the cords are densely arranged, there is a possibility that the cords may not be sufficiently restrained. On the other hand, if the cord is too thick, it will be difficult to cover the monofilament cord with rubber without any gaps, and it will not easily undergo shear deformation, making it difficult to obtain sufficient handling stability at high speeds.

[0024] [2] More preferred aspects of the tire disclosed herein The tire disclosed herein can achieve even greater effects by employing the following aspects.

[0025] 1. The relationship between the physical properties of the coated rubber composition and the number of reinforcing cords arranged in the arrangement. In the tire disclosed herein, the complex elastic modulus E* (MPa) of the rubber composition covering the reinforcing cords in the belt layer, measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: elongation, the loss tangent (tanδ) measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: tension, and the number of reinforcing cords e (cords) arranged per 5cm in the tire width direction in the tread preferably satisfy [(tanδ / E*) / e]×1000≦0.2 (Equation 4).

[0026] When the tire tread deforms while rolling, heat is generated in the belt layer. At this time, if the number of reinforcing cords arranged per 5 cm (hereinafter referred to as "density (ends)") is not appropriate, the overlay rubber layer may soften and handling stability may be reduced.

[0027] Therefore, the relationship between the index (tanδ / E*) and density (e) related to the heating of the belt layer was investigated. The results showed that if [(tanδ / E*) / e]×1000≦0.2 (Equation 4), the heating of the belt layer caused by deformation of the tread during rolling was suppressed, and softening was also suppressed. Furthermore, the results indicated that the rigidity of the belt layer could be satisfactorily maintained, the increase in belt layer deformation and heating could be suppressed, and low rolling resistance and handling stability could be achieved. Moreover, the results showed that [(tanδ / E*) / e]×1000 is more preferably 0.18 or less, more preferably 0.15 or less, more preferably 0.13 or less, and more preferably 0.12 or less.

[0028] The number of monofilaments (density) refers to the average number of cords arranged per 5 cm in the tire width direction under a standard rim, internal pressure of 250 kPa, and no load. It can be determined by measuring the number of cords arranged over a width of 5-10 cm centered on the tire equator in a section cut radially with a thickness of 2-4 cm, and calculating the average number of cords per 5 cm. A density e (cords / 5 cm) is more preferably 55 cords / 5 cm or more, further preferably 75 cords / 5 cm or more, and even more preferably 90 cords / 5 cm or more.

[0029] In this paper, the complex elastic modulus E* (MPa) and the loss tangent (tanδ) can be measured, for example, using a viscoelastic measuring device (e.g., the "Eplexor" manufactured by GABO (registered trademark)). A specific complex elastic modulus E* (MPa) is preferably 8.7 MPa or more, more preferably 9.4 MPa or more, and even more preferably 10.5 MPa or more. Furthermore, a specific loss tangent (tanδ) is preferably 0.08 or more, more preferably 0.10 or more, and even more preferably 0.13 or more.

[0030] In particular, (tanδ / E*) is preferably 0.002 or more and 0.017 or less (more preferably 0.015 or less, even more preferably 0.014 or less, even more preferably 0.01 or less, even more preferably 0.009 or less).

[0031] 2. Multi-layered belt structure In this disclosure, the belt layer is multi-layered by providing at least two layers. In at least one group of belt layers that are adjacent in the radial direction of the tire, the average distance D (mm) between the cords in each belt layer in the tread area is preferably 0.6 mm or less, more preferably 0.5 mm or less, even more preferably 0.45 mm or less, and even more preferably 0.22 mm or less.

[0032] As a result, the belt layers work together to properly constrain the tread and suppress the amount of tread deformation during rolling, thus maintaining low rolling resistance and handling stability at high speeds.

[0033] When the belt layer is multilayered, at least one belt layer should satisfy the above relationship about "[(tanδ / E*) / e]×1000".

[0034] In the case of multi-layered belt layers, in at least one group of belt layers adjacent to each other in the radial direction of the tire, the angle formed by the cords in the belt layer in the tread in the circumferential direction of the tire is preferably 65° or less, more preferably 60° or less, even more preferably 58° or less, and even more preferably 46° or less.

[0035] By arranging belt layers that are inclined at appropriate angles to each other, a hoop effect can be achieved, which can tightly restrain the tread almost the entire width, thereby suppressing the amount of tread deformation during rolling and maintaining low rolling resistance and handling stability at high speeds.

[0036] The average distance D (mm) between the aforementioned (tanδ / E*) and the cords preferably satisfies (tanδ / E*)×D×1000≦8.0 (Equation 6). (tanδ / E*)×D×1000 is more preferably 6.2 or less, even more preferably 4.3 or less, even more preferably 4.1 or less, and even more preferably 3.0 or less. As a result, the heat generation suppression of the belt layer and the restraint of the tread area through the belt layer function appropriately, and low rolling resistance and handling stability can be maintained at high speeds.

[0037] 3. Grooves in the tire tread The tire disclosed herein has circumferential grooves extending continuously in the circumferential direction in the tread. Preferably, the groove width L at 80% of the maximum depth of the circumferential grooves is... 80 The ratio of the circumferential groove width L0 on the tread contact surface to the groove width L0 (L 80 The value of L0 is preferably 0.2 or higher and 0.7 or lower. As a result, movement of the entire landmass can be suppressed at the bottom surface of the landmass in the tread area, thereby effectively suppressing uneven wear of the tread area during high-speed driving and significantly improving durability. 80 / L0 is preferably 0.35 or more, more preferably 0.40 or more, and even more preferably 0.45 or more. In addition, L80 / L0 is preferably 0.65 or less, more preferably 0.60 or less, and even more preferably 0.55 or less.

[0038] The L0 and L 80 These refer to the straight-line distance (L0) between the groove ends at the tread surface of a tire mounted on a standard rim with an internal pressure of 250 kPa and under no-load conditions, and the minimum distance (L) between the groove walls at 80% of the groove depth. 80 Simply put, it can be determined by pressing down the bead portion of the section cut radially from the tire with a width of 2 to 4 cm to align with the corresponding rim width.

[0039] Preferably, the tread portion has multiple circumferential grooves, the total cross-sectional area of ​​which is 10% to 30% of the total cross-sectional area of ​​the tread portion. As a result, tread portion movement can be suppressed, uneven wear of the tread portion during high-speed driving can be effectively suppressed, and durability can be significantly improved. More preferably, it is 15% to 27%, further preferably 18% to 25%, and particularly preferably 21% to 23%.

[0040] The cross-sectional area of ​​the circumferential groove refers to the total area formed by the straight line connecting the ends of the circumferential grooves and the groove walls in a tire mounted on a standard rim, with an internal pressure of 250 kPa and under no load. Simply put, it can be calculated by pressing down the bead portion of a section cut radially from the tire with a width of 2–4 cm to align it with the corresponding rim width.

[0041] The tread cross-sectional area refers to the area radially outer from the belt layer of the tire in a tire mounted on a standard rim, with an internal pressure of 250 kPa and under no-load conditions. This area is defined by a straight line connecting the ends of the circumferential grooves of the tread and two straight lines parallel to the equatorial plane (these lines pass through the tread surface profile formed by the tread surface and the two widest ends of the belt layer). When a belt reinforcement layer using organic fibers and / or steel cords is configured radially outer from the belt layer, it refers to the area radially outer from the belt reinforcement layer.

[0042] Furthermore, preferably, the tread has multiple lateral grooves extending axially along the tire, the total volume of which is 2.0% to 5.0% of the tread volume. As a result, tread movement can be suppressed, thereby effectively suppressing uneven tread wear and significantly improving durability. More preferably, it is 2.2% to 4.0%, even more preferably 2.5% to 3.5%, and particularly preferably 2.7% to 3.0%.

[0043] The volume of the tread portion mentioned above refers to the volume obtained by extending the area of ​​the tread portion circumferentially along the tire's width. Simply put, it can be obtained by multiplying the area of ​​the tread portion by the length of the tire's outer circumference (Dt×π). The volume includes the volume of the main grooves and lateral grooves, and is located at the widest end of the breaker layer in the width direction.

[0044] Furthermore, the volume of the lateral grooves refers to the total volume formed by the surfaces connecting the ends of the lateral grooves and the groove walls in a tire mounted on a standard rim, with an internal pressure of 250 kPa and under no load. Simply put, it can be calculated by aligning the bead portions of segments cut radially from the tire (2-4 cm wide) with the corresponding rim width, calculating the volume of each lateral groove, and then multiplying it by the number of grooves. Additionally, the volume of the tread can be calculated by calculating the area of ​​the portion of the tread excluding the lateral grooves based on the segments, multiplying this result by the outer diameter, and then determining the difference between the volume of the lateral grooves and this result.

[0045] Furthermore, from the perspective of improving handling stability at high speeds by generating friction with the road surface at the ends of the grooves in the width direction of the tread, suppressing excessive deformation of the tread, and increasing the reaction force generated in the tread, the lateral grooves preferably include lateral grooves with a groove width Gw to groove depth Gd ratio (Gw / Gd) of 0.50 or more and 0.80 or less. More preferably, it is 0.53 or more and 0.77 or less, even more preferably 0.55 or more and 0.75 or less, and particularly preferably 0.60 or more and 0.70 or less.

[0046] The groove width and groove depth of the aforementioned lateral grooves are, in a tire with an internal pressure of 250 kPa and under no-load conditions, the longest straight line perpendicular to the groove direction among the straight lines connecting the ends of the tread surface of the lateral grooves, and the maximum depth of the lateral groove. Simply put, it can be calculated by pressing down the bead portion of a section cut radially from the tire with a width of 2–4 cm to align with the corresponding rim width.

[0047] 4. Tire shape In the tire disclosed herein, when the tire is mounted on a standard rim and the internal pressure is 250 kPa, a specific outer diameter Dt (mm) is preferably 515 mm or more, more preferably 558 mm or more, even more preferably 585 mm or more, even more preferably 622 mm or more, even more preferably 623 mm or more, even more preferably 624 mm or more, even more preferably 627 mm or more, even more preferably 628 mm or more, even more preferably 629 mm or more, even more preferably 640 mm or more, even more preferably 658 mm or more, and even more preferably 673 mm or more. On the other hand, although the upper limit is not particularly limited, it is preferably less than 843 mm, more preferably less than 725 mm, even more preferably less than 707 mm, and even more preferably less than 685 mm. By setting the outer diameter Dt within the above range, it is believed that a favorable moment of inertia can be obtained during rolling, and a reaction force can be easily generated when setting the steering angle.

[0048] The specific cross-sectional width Wt (mm) is preferably 115 mm or more, more preferably 130 mm or more, even more preferably 150 mm or more, even more preferably 155 mm or more, even more preferably 170 mm or more, even more preferably 175 mm or more, even more preferably 183 mm or more, even more preferably 184 mm or more, even more preferably 185 mm or more, and even more preferably 193 mm or more. On the other hand, although there is no particular upper limit, it is preferably less than 305 mm, more preferably less than 245 mm, even more preferably less than 210 mm, even more preferably less than 205 mm, even more preferably less than 201 mm, even more preferably less than 200 mm, and even more preferably less than 200 mm. By setting the cross-sectional width Wt within the above range, the rigidity in the width direction can be increased, and it is believed that it is easier to obtain good handling stability at high speeds.

[0049] The specific cross-sectional height Ht (mm) is preferably 37 mm or more, more preferably 87 mm or more, and even more preferably 95 mm or more. On the other hand, it is preferably less than 180 mm, more preferably less than 112 mm, and even more preferably less than 101 mm.

[0050] Furthermore, in this disclosure, considering the stability of ride comfort during driving, (Dt-2×Ht) is preferably 450 (mm) or more, more preferably 470 (mm) or more, and even more preferably 480 (mm) or more. On the other hand, considering the deformation of the tread, it is preferably less than 560 (mm), more preferably less than 530 (mm), and even more preferably less than 510 (mm).

[0051] [3] Implementation The present disclosure will be described in detail below based on implementation methods.

[0052] 1. Rubber composition for belt layer (1) Materials The rubber composition constituting the belt layer of the tire disclosed herein can be obtained from the rubber components and other compounding materials described below.

[0053] (a) Rubber composition In this embodiment, the rubber composition is not particularly limited, and commonly used rubbers (polymers) in tire manufacturing can be used, such as isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), and butyl rubber. Isoprene rubber is preferred, and NR is preferred because polyisoprene has a near 100% cis structure and superior tensile strength compared to other rubber compositions. It should be noted that BR and SBR can be used together as needed.

[0054] (a-1) Isoprene-based rubber In 100 parts by weight of rubber composition, the content (total content) of isoprene rubber is preferably 60 parts by weight or more, more preferably 80 parts by weight or more, and even more preferably 90 parts by weight or more.

[0055] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR, but NR is preferred from the perspective of superior strength.

[0056] For example, NRs commonly used in the tire industry, such as SIR20, RSS#3, and TSR20, can be used. IRs are not particularly limited; for example, IRs commonly used in the tire industry, such as IR2200, can be used. Examples of modified NRs include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These can be used alone or in combination of two or more.

[0057] (a-2)BR In this embodiment, as needed, 5 to 25 parts by weight of BR and NR can be used together in the rubber composition.

[0058] The weight-average molecular weight of BR is, for example, greater than 100,000 and less than 2,000,000. The vinyl bonding content of BR (1,2-bonded butadiene units) is, for example, greater than 1% by mass and less than 30% by mass. The cis content of BR is, for example, greater than 1% by mass and less than 98% by mass. The trans content of BR is, for example, greater than 1% by mass and less than 60% by mass. The cis content can be determined by infrared absorption spectroscopy.

[0059] There are no particular limitations on BR. BR with high cis content (cis content of 90% or more) or low cis content or containing isotactic polybutadiene crystals can be used. BR can be unmodified or modified. Modified BR can be, for example, S-modified BR modified with a compound (modifier) ​​represented by the following formula.

[0060] [Chemistry 1]

[0061] In the formula, R 1 R 2 and R 3Same or different, indicating alkyl, alkoxy, silyloxy, acetal, carboxyl (-COOH), mercapto (-SH) or their derivatives. R 4 and R 5 Same or different, indicating hydrogen atoms or alkyl groups. R 4 and R 5 It can combine with nitrogen atoms to form a ring structure. n represents an integer.

[0062] Examples of modified BRs modified with compounds (modifiers) represented by the above formula include BRs whose polymer ends (active ends) have been modified with compounds represented by the above formula.

[0063] R 1 R 2 and R 3 Preferably, it is an alkoxy group (preferably an alkoxy group with 1 to 8 carbon atoms, more preferably an alkoxy group with 1 to 4 carbon atoms). As R 4 and R 5 Alkyl groups (preferably alkyl groups having 1 to 3 carbon atoms) are suitable. n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. Furthermore, in R... 4 and R 5 When combined with a nitrogen atom to form a ring structure, it is preferably a 4- to 8-membered ring. Alkoxy groups also include cycloalkoxy groups (such as cyclohexyloxy) and aryloxy groups (such as phenoxy and benzyloxy).

[0064] Specific examples of modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These can be used alone or in combination of two or more.

[0065] As a modified BR, modified BR can also be used with the following compounds (modifiers). Examples of modifiers include: Polyhydric alcohol polyglycidyl ethers, such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether and trimethylolpropane triglycidyl ether; Polyglycidyl ethers of aromatic compounds having two or more phenolic groups, such as bisphenol A diglycidyl ether; Polyepoxides, such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxide liquid polybutadiene; Tertiary amines containing epoxy groups, such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; Diglycidylamino compounds, such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-xylyldiamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-diaminomethylcyclohexane; Acyl chlorides containing amino groups, such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholine carbamoyl chloride, 1-pyrrolidine carbamoyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; Silane compounds containing epoxy groups, such as 1,3-bis-(glycidoxypropyl)-tetramethyldisiloxane, (3-glycidoxypropyl)-pentamethyldisiloxane, etc. Silane compounds containing a sulfide group, such as (trimethylsilyl)[3-(trimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted aziridine compounds, such as ethyleneimine and propyleneimine; Alkoxysilanes, such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (Thio)benzophenone compounds having an amino group and / or a substituted amino group, such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; Benzaldehyde compounds having an amino group and / or substituted amino groups, such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones, such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidinones, such as N-methyl-2-piperidinone, N-vinyl-2-piperidinone, N-phenyl-2-piperidinone; and N-substituted lactams, such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam. In addition, examples include N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethylidene urea, 1,3-divinylethylidene urea, 1,3-diethyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, and 1,7-bis(methylethylamino)-4-heptanone. Modification using the above compounds (modifiers) can be carried out by known methods.

[0066] As a modified BR, tin-modified BR can also be used, for example. Tin-modified BR is obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound. Preferably, tin-modified BR has terminals further bonded by tin-carbon bonds.

[0067] Examples of lithium initiators include lithium compounds (e.g., alkyllithium, aryllithium, vinyllithium, organotin lithium, and organonitrile lithium compounds) and lithium metal. By using lithium initiators as initiators for tin-modified BR, tin-modified BR with high vinyl content and low cis content can be produced.

[0068] Examples of tin compounds include tin tetrachloride, butyltin trichloride, dibutyltin dichloride, dioctyltin dichloride, tributyltin chloride, triphenyltin chloride, diphenyldibutyltin, triphenylethoxytin, diphenyldimethyltin, xylyltin chloride, diphenyldioctanoate, divinyldiethyltin, tetrabenzyltin, dibutyldistearate, tetraallyltin, and styrene-p-tributyltin.

[0069] The tin atom content in the tin-modified BR is preferably 50 ppm or more, more preferably 60 ppm or more. On the other hand, it is preferably 3000 ppm or less, more preferably 2500 ppm or less, and even more preferably 250 ppm or less.

[0070] Furthermore, the molecular weight distribution (Mw / Mn) of the tin-modified BR is preferably 2 or less, and more preferably 1.5 or less.

[0071] Furthermore, the vinyl bonding content in the tin-modified BR is preferably 5% by mass or more, more preferably 7% by mass or more. On the other hand, the vinyl bonding content in the tin-modified BR is preferably 50% by mass or less, more preferably 20% by mass or less.

[0072] The S-modified BR and tin-modified BR mentioned above can be used alone or in combination of two or more of them.

[0073] As a BR (Brandinger), products from companies such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Zeon Corporation can be used.

[0074] (a-3)SBR In this embodiment, the rubber component may optionally contain 5 to 25 parts by weight of SBR together with NR, or may be used in combination with the above-mentioned BR.

[0075] The weight-average molecular weight of the SBR is, for example, greater than 100,000 and less than 2,000,000. The styrene content of the SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and even more preferably greater than 20% by mass. On the other hand, it is preferably less than 50% by mass, more preferably less than 40% by mass, and even more preferably less than 35% by mass. The vinyl bond content of the SBR is, for example, greater than 5% by mass and less than 70% by mass. The structural identification of the SBR (determination of styrene content and vinyl bond content) can be performed using, for example, a device from the JNM-ECA series manufactured by JEOL Ltd.

[0076] There are no particular limitations on SBR; for example, emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR) can be used. SBR can be unmodified or modified. These can be used alone or in combination of two or more.

[0077] The modified SBR can be any SBR having functional groups that interact with fillers (e.g., silica). Examples include: end-modified SBRs in which at least one end is modified by a compound (modifier) ​​having the aforementioned functional groups (end-modified SBRs with the aforementioned functional groups at the ends), main-chain modified SBRs having the aforementioned functional groups in the main chain, and main-chain end-modified SBRs having the aforementioned functional groups in both the main chain and the ends (e.g., main-chain end-modified SBRs having the aforementioned functional groups in the main chain and at least one end modified by the aforementioned modifier), and end-modified SBRs modified (coupled) by a polyfunctional compound having two or more epoxy groups in the molecule and introducing hydroxyl or epoxy groups therein.

[0078] As an SBR, for example, SBR manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Zeon Corporation can be used. SBR can be used alone or in combination of two or more types.

[0079] (a-4) Other rubber components In addition, as other rubber components, depending on the requirements, rubber (polymers) commonly used in tire manufacturing may be included. For example, nitrile butadiene rubber (NBR).

[0080] (b) Compounding materials other than rubber components (b-1) Packing In this embodiment, the rubber composition preferably contains fillers. Specific examples of fillers include carbon black, silica, graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. Carbon black is preferably used as a reinforcing agent. Furthermore, silica is preferably used as a reinforcing agent as needed, in which case it is preferably used in conjunction with a silane coupling agent.

[0081] (i) Carbon black The rubber composition preferably contains carbon black. The carbon black content relative to 100 parts by weight of the rubber component is preferably 10 parts by weight or more and 100 parts by weight or less, more preferably 40 parts by weight or more and 70 parts by weight or less, and even more preferably 50 parts by weight or more and 60 parts by weight or less.

[0082] Carbon black is not particularly limited, but examples include: furnace black (furnace black), such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black; thermal cracking black (thermal cracking black), such as FT and MT; and channel black (channel black), such as EPC, MPC, and CC. One of these can be used alone, and two or more can be used in combination.

[0083] The nitrogen adsorption specific surface area (N2SA) of carbon black is, for example, greater than 30 m². 2 / g, less than 250m 2 / g. The dibutyl phthalate (DBP) absorption of carbon black is, for example, greater than 50 ml / 100g and less than 250 ml / 100g. The nitrogen adsorption specific surface area of ​​carbon black is determined according to ASTM D4820-93, and the DBP absorption is determined according to ASTM D2414-93.

[0084] There are no specific limitations on the type of carbon black used, but examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available products include those from companies such as Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nikka Carbon Co., Ltd., and Columbia Carbon Co., Ltd. These can be used individually or in combination of two or more.

[0085] (ii) Silicon dioxide The rubber composition preferably further contains silica as needed. From the perspective of obtaining good durability, the BET specific surface area of ​​silica is preferably greater than 140 m². 2 / g, more preferably greater than 160m 2 / g. On the other hand, from the perspective of achieving good low rolling resistance at high speeds, it is preferable to have less than 250m. 2 / g, more preferably less than 220m 2 / g.

[0086] Furthermore, when not used in combination with a silane coupling agent, the silica content is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of the rubber component. On the other hand, it is preferably 25 parts by mass or less, more preferably 15 parts by mass or less. When used in combination with a silane coupling agent, it is preferably 25 parts by mass or more. On the other hand, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. The above-mentioned BET specific surface area is the N2SA value determined by the BET method according to ASTM D3037-93.

[0087] Examples of silica include dry silica (anhydrous silica) and wet silica (hydrated silica). Wet silica is preferred because it has a large number of silanol groups.

[0088] As silica, products from companies such as Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., and Tokuyama Co., Ltd. can be used.

[0089] (iii) Silane coupling agent As mentioned above, when using silica, a silane coupling agent can be used in conjunction. There are no particular limitations on the silane coupling agent, but examples include sulfide-based silane coupling agents, such as 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-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-triethoxysilylbutyl)tetrasulfide, etc. 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,N-dimethylthio Carbamoyl tetrasulfide, 2-triethoxysilyl ethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilyl propyl methacrylate monosulfide; mercapto-based silane coupling agents, such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; vinyl-based silane coupling agents, such as vinyltriethoxysilane and vinyltrimethoxysilane. Alkane; amino-based silane coupling agents, such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; epoxypropoxy-based silane coupling agents, such as γ-epoxypropoxypropyltriethoxysilane and γ-epoxypropoxypropyltrimethoxysilane; nitro-based silane coupling agents, such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; chlorinated silane coupling agents, such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. These can be used alone or in combination of two or more.

[0090] As silane coupling agents, products from companies such as Degussa, Momentive, Shin-Etsu Silicone, Tokyo Chemical Industries, Azumax, and Toray Corning can be used.

[0091] The content of silane coupling agent relative to 100 parts by weight of silicon dioxide is, for example, greater than 3 parts by weight and less than 15 parts by weight.

[0092] (iv) Other packing materials In addition to carbon black and silica, the rubber composition may further contain fillers commonly used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. The content of these fillers relative to 100 parts by weight of the rubber component is, for example, greater than 0.1 parts by weight and less than 200 parts by weight.

[0093] (b-2) Curing resin components The rubber composition preferably contains a curable resin component, such as modified resorcinol resin or modified phenolic resin. As a result, adhesion to steel cord can be improved without significantly deteriorating thermal properties and elongation at break, and large reaction forces can be easily generated in both the rubber and the steel cord.

[0094] Examples of specific modified resorcinol resins include Sumikanol 620 (modified resorcinol resin) manufactured by Taoka Chemical Industry Co., Ltd., and examples of modified phenolic resins include PR12686 (cashew oil modified phenolic resin) manufactured by Sumitomo Bakelite Co., Ltd.

[0095] For example, from the perspective of sufficiently increasing the complex elastic modulus and obtaining a large reaction force during deformation, the content of the curable resin component is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the rubber component. On the other hand, from the perspective of maintaining the fracture strength, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less.

[0096] When using modified resorcinol resin, it is preferable to also contain a methylene donor as a curing agent. Examples of methylene donors include hexamethylenetetramine (HMT), hexamethoxyhydroxymethyl melamine (HMMM), and hexamethyl melamine pentamethyl ether (HMMPME). It is preferable to contain, for example, 5 parts by weight or more, up to about 15 parts by weight, relative to 100 parts by weight of the curable resin component. If this amount is too small, sufficient complex modulus of elasticity may not be obtained. On the other hand, if this amount is too large, the viscosity of the rubber may increase, and processability may deteriorate.

[0097] For example, Sumikanol 507 manufactured by Taoka Chemical Co., Ltd. can be used as a specific methylene donor.

[0098] (b-3) Resin composition From a processability (tackiness) perspective, the rubber composition preferably contains a resin component as needed. The resin component may be solid or liquid at room temperature. Specific examples of resin components include rosin-based resins, styrene-based resins, benzofuran-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. The resin component content is preferably greater than 2 parts by weight and less than 45 parts by weight, more preferably less than 30 parts by weight, relative to 100 parts by weight of the rubber composition.

[0099] Rosin-based resins are resins containing rosin acid, obtained through the processing of rosin, as their main component. These rosin-based resins (rosins) can be classified according to the presence or absence of modification, and can be categorized as unmodified rosin (unmodified rosin) and rosin modifiers (rosin derivatives). Unmodified rosin includes tall rosin (also known as tall oil rosin), resin rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin modifiers are modifications of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosin derivatives, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0100] Styrene-based resins are polymers that use styrene-based monomers as constituent monomers. Examples include polymers obtained by polymerizing styrene-based monomers as a major component (50% by mass or more). Specifically, examples include homopolymers obtained by polymerizing styrene-based monomers alone (e.g., styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene), copolymers obtained by copolymerizing two or more styrene-based monomers, and copolymers obtained by copolymerizing styrene-based monomers and other monomers that can be copolymerized with styrene-based monomers.

[0101] Examples of the other monomers mentioned above include: acrylonitriles, such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids, such as acrylic acid and methacrylic acid; unsaturated carboxylic acid esters, such as methyl acrylate and methyl methacrylate; dienes, such as chloroprene, butadiene and isoprene; alkenes, such as 1-butene and 1-pentene; and α,β-unsaturated carboxylic acids and their anhydrides, such as maleic anhydride.

[0102] Among benzofuran-based resins, benzofuran-indene resins are preferred. Benzofuran-indene resins are resins containing benzofuran and indene as monomeric components constituting the resin's backbone (main chain). Examples of monomeric components included in the backbone other than benzofuran and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0103] The content of benzofuran-indene resin relative to 100 parts by weight is, for example, greater than 1.0 parts by weight and less than 50.0 parts by weight.

[0104] The hydroxyl value (OH value) of benzofuran-indene resin is, for example, greater than 15 mg KOH / g and less than 150 mg KOH / g. The OH value is the amount of potassium hydroxide required to neutralize the acetic acid bound to the hydroxyl group when 1 g of resin is acetylated, and is expressed in milligrams. The OH value is determined by potentiometric titration (JIS K 0070:1992).

[0105] The softening point of benzofuran-indene resin is, for example, greater than 30°C and less than 160°C. The softening point is the temperature at which the ball falls when the softening point specified in JIS K 6220-1:2001 is measured using a ring-and-ball softening point tester.

[0106] Examples of terpene resins include polyterpenes, terpenoid phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrides. Terpene compounds are composed of (C5H8) resins. n The composition of hydrocarbons and their oxygen-containing derivatives represents hydrocarbons that are classified as monoterpenes (C6N). 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 Compounds with terpenes as their basic skeleton include α-pinene, β-pinene, dipentene, limonene, myrcene, allociperene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinene oil, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0107] Examples of polyterpenes include terpene resins, such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin made from the aforementioned terpene compounds, and hydrogenated terpene resins obtained by hydrogenating such terpene resins can also be cited as examples. Examples of terpenoids and phenols include resins obtained by copolymerizing the aforementioned terpene compounds with phenolic compounds, and resins obtained by hydrogenating such resins. Specifically, resins obtained by condensing the aforementioned terpene compounds, phenolic compounds, and formalin can be cited as examples. 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 such resins. Regarding aromatic compounds, there are no particular limitations as long as they are compounds with aromatic rings. For example, examples include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, and phenol containing an unsaturated hydrocarbon group; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and naphthol containing an unsaturated hydrocarbon group; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and styrene containing an unsaturated hydrocarbon group; benzofuran; indene; etc.

[0108] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, equivalent to cyclopentadiene, pentene, pentadiene, isoprene, etc. Dicyclopentadiene resin (DCPD resin) is preferred as a C5-based petroleum resin.

[0109] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which can be hydrogenated or modified. Examples of C9 fractions include petroleum fractions having 8 to 10 carbon atoms, equivalent to vinyltoluene, alkylstyrene, indene, methylindene, etc. As specific examples, benzofuran-indene resins, benzofuran resins, indene resins, and aromatic vinyl resins are preferred. As aromatic vinyl resins, homopolymers of α-methylstyrene or styrene, or copolymers of α-methylstyrene and styrene, are preferred because they are economical, easy to process, and have excellent exothermic properties. Copolymers of α-methylstyrene and styrene are more preferred. As aromatic vinyl resins, commercially available products from companies such as Kraton and Eastman Chemical can be used, for example.

[0110] "C5C9 resin" refers to a resin (which may be hydrogenated or modified) obtained by copolymerizing the aforementioned C5 fraction and C9 fraction. Examples of C5 and C9 fractions include the aforementioned petroleum fractions. Commercially available products from Tosoh Corporation, LUHUA Corporation, etc., can be used as C5C9 resins, for example.

[0111] There are no particular limitations on acrylic resins. For example, solvent-free acrylic resins can be used.

[0112] As solvent-free acrylic resins, examples include (meth)acrylic resins (polymers) synthesized by high-temperature continuous polymerization (high-temperature continuous bulk polymerization) (as described in USP 4,414,370, JP-A-S59-6207, JP-B-H5-58005, JP-A-H1-313522, USP 5,010,166, and the Toa Synthetic Research Yearbook TREND 2000 No. 3, pp. 42-45). It should be noted that in this disclosure, "(meth)acrylic acid" refers to both methacrylic acid and acrylic acid.

[0113] Examples of monomeric components constituting the acrylic resin include (meth)acrylic acid derivatives, such as (meth)acrylic acid, (meth)acrylates (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylamide derivatives.

[0114] As monomer components constituting the acrylic resin, aromatic vinyl monomers (e.g., styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, etc.) together with (meth)acrylic acid and / or (meth)acrylic acid derivatives can be used.

[0115] The acrylic resin may be a resin composed solely of (meth)acrylic acid components, or it may be a resin that also contains components other than (meth)acrylic acid components as constituents. The acrylic resin may contain hydroxyl, carboxyl, silanol, or other groups.

[0116] As a resin component, for example, products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Co., Ltd., Rutgers Chemicals, Ltd., BASF, Arizona Chemical Co., Ltd., Nippon Paint Co., Ltd., Nippon Shokubai Co., Ltd., JX Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., or Taoka Chemical Industry Co., Ltd. can be used.

[0117] (b-4) Organic cobalt acid The rubber composition preferably contains cobalt organic acid. Since cobalt organic acid acts as a crosslinker between the cord and the rubber, the presence of this component can improve the adhesion between the cord and the rubber.

[0118] Examples of cobalt organic acids include cobalt stearate, cobalt naphthenate, cobalt neodecanoate, and cobalt-3 neodecanoate.

[0119] Regarding the cobalt concentration in the rubber composition, the content of cobalt organic acid is preferably 500 ppm or more, more preferably 700 ppm or more, and even more preferably 900 ppm or more. On the other hand, it is preferably 1500 ppm or less, more preferably 1300 ppm or less. If this amount is too low, there is a risk that sufficient adhesion between the steel cord coating and the rubber cannot be ensured. On the other hand, if this amount is too high, the oxidative deterioration of the rubber becomes significant, and there is a possibility of deterioration in the fracture performance.

[0120] (b-5) Anti-reversion agent As needed, the rubber composition preferably contains a reversion inhibitor. This can inhibit reversion and improve durability. The content of the reversion inhibitor relative to 100 parts by weight of the rubber component is preferably 0.1 parts by weight or more and 3 parts by weight or less, more preferably 0.2 parts by weight or more and 2.5 parts by weight or less, and even more preferably 0.3 parts by weight or more and 2 parts by weight or less. For example, Perkalink 900 (1,3-bis(citraconimide methyl)benzene) manufactured by Flexsys can be used as a specific reversion inhibitor.

[0121] (b-6) Anti-aging agents The rubber composition preferably contains an antioxidant. The antioxidant content is, for example, greater than 1 part by weight and less than 10 parts by weight relative to 100 parts by weight of the rubber component.

[0122] Examples of antioxidants include: naphthylamine-based antioxidants, such as phenyl-α-naphthylamine; diphenylamine-based antioxidants, such as octyl 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, and N,N'-di-2-naphthyl-p-phenylenediamine; quinoline-based antioxidants, such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants, such as 2,6-di-tert-butyl-4-methylphenol and styreneated phenol; and bisphenol, triphenol, and polyphenol-based antioxidants, such as tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. These can be used alone or in combination of two or more.

[0123] As an anti-aging agent, products from companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., and Flexsys can be used.

[0124] (b-7) Stearic acid The rubber composition may contain stearic acid. The stearic acid content, relative to 100 parts by weight of the rubber component, is, for example, greater than 0.5 parts by weight and less than 10.0 parts by weight. As stearic acid, conventionally known stearic acids can be used, such as products from Nippon Oil Co., Ltd., NOF Corporation, Kao Corporation, Fujifilm, and Koh Geny Pharmaceutical Co., Ltd., and Chiba Fatty Acid Co., Ltd., etc.

[0125] (b-8) Zinc oxide The rubber composition may contain zinc oxide. The zinc oxide content, relative to 100 parts by weight of the rubber component, is, for example, greater than 0.5 parts by weight and less than 15 parts by weight. Conventionally known zinc oxides may be used. For example, products from Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd. may be used.

[0126] (b-9) Crosslinking agents and vulcanization accelerators The rubber composition preferably contains a crosslinking agent (e.g., sulfur). The content of the crosslinking agent is, for example, greater than 0.1 parts by weight and less than 10.0 parts by weight relative to 100 parts by weight of the rubber component.

[0127] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, and soluble sulfur, which are commonly used in the rubber industry. These can be used alone or in combination of two or more.

[0128] For example, products from companies such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexsys Co., Ltd., Nippon Inkyu Corporation, and Hosoi Chemical Industry Co., Ltd. can be used as sulfur.

[0129] Examples of crosslinking agents other than sulfur include: sulfur-containing vulcanizing agents, such as Tackirol V200 manufactured by Taoka Chemical Industry Co., Ltd., Duralink HTS (sodium 1,6-hexamethylene dithiosulfate dihydrate) manufactured by Flexsys, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyl dithiohexane)) manufactured by Lanxess; and organic peroxides, such as dicumyl peroxide.

[0130] The rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, greater than 0.3 parts by weight and less than 10.0 parts by weight per 100 parts by weight of the rubber component.

[0131] Examples of vulcanization accelerators include: thiazole-based vulcanization accelerators, such as 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based vulcanization accelerators, such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators, such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-oxoethylene-2-benzothiazole sulfenamide, N-oxoethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators, such as diphenylguanidine, di-o-tolylguanidine, and o-tolyl biguanide. These can be used individually or in combination of two or more.

[0132] (b-10) Other In addition to the above-mentioned components, the rubber composition may further contain additives commonly used in the tire industry, such as fatty acid metal salts, carboxylic acid metal salts, and organic peroxides. The content of these additives relative to 100 parts by weight of the rubber component is, for example, greater than 0.1 parts by weight and less than 200 parts by weight.

[0133] (2) Preparation of rubber composition The rubber composition is made by conventional methods, for example by a manufacturing method including the following steps: a basic mixing step of mixing the rubber components with fillers (e.g., carbon black), and a final mixing step of mixing the mixture obtained in the basic mixing step with a crosslinking agent.

[0134] Mixing can be carried out using known (closed) mixing machines (such as Banbury mixers, kneaders, open rolls).

[0135] The mixing temperature in the basic mixing step is, for example, above 50°C and below 200°C, and the mixing time is, for example, greater than 30 seconds and less than 30 minutes. In addition to the above-mentioned components, commonly used compounding agents in the rubber industry (such as softeners (including oils), stearic acid, zinc oxide, antioxidants, waxes, vulcanization accelerators, etc.) may be added as needed during the basic mixing step.

[0136] In the final mixing step, the compound obtained in the basic mixing step is mixed with a crosslinking agent. The mixing temperature in the final mixing step is, for example, above room temperature and below 80°C, and the mixing time is, for example, greater than 1 minute and less than 15 minutes. In addition to the above components, vulcanization accelerators, zinc oxide, etc., may be added as needed in the final mixing step.

[0137] 2. Manufacturing of belt components The belt component can be manufactured by applying an adhesive to both sides of reinforcing cords (monofilament cords, such as steel cords) arranged in parallel at predetermined intervals (50 cords / 5cm or more).

[0138] 3. Tire manufacturing The tire disclosed herein can be manufactured by forming the belt component obtained above together with other tire components on a tire forming machine using conventional methods to produce an uncured tire.

[0139] Specifically, on the forming drum, the inner liner, which serves as a component to ensure the airtightness of the tire, the tire carcass, which serves as a component to withstand the load, impact, and air pressure of the tire, and the belt component, which serves as a component to strongly fasten the tire carcass to improve the tread rigidity, are wound up. Then, the two ends of the tire carcass are fixed to the two side edges, and a bead portion, which serves as a component to fix the tire to the rim, is arranged to form a ring. Subsequently, the tread is attached to the center of the outer periphery, and the sidewall is attached to the radially outer side to form the sidewall portion; thus, an uncured tire is produced.

[0140] In this embodiment, as described above, from the perspective of improving the restraint force on the tread during driving and promoting the suppression of outer diameter growth, the belt layer is preferably provided with at least two layers. In this case, the average distance D (mm) between the belt layers in the tread portion is preferably 0.6 mm or less. Furthermore, preferably, the angle formed by the belt layers in the tread portion in the tire circumferential direction is 65° or less.

[0141] The angle of the steel cord is the angle of the steel cord relative to the tire's circumference when the tire is not inflated, and it can be determined by peeling the tread from the radially outer side of the tire.

[0142] The uncured tires are then heated and pressurized in a vulcanizing machine to obtain a tire. The vulcanization step can be carried out using known vulcanization methods. Vulcanization temperatures are, for example, above 120°C and below 200°C, and vulcanization times are, for example, greater than 5 minutes and less than 15 minutes.

[0143] At this time, when the tire is mounted on a standard rim and has an internal pressure of 250 kPa, the tire is shaped to satisfy the above (Formula 1).

[0144] Examples of specific tires that can satisfy the above (Equation 1) include tires with the following size markings, for example: 145 / 60R18, 145 / 60R19, 155 / 55R18, 155 / 55R19, 155 / 70R17, 155 / 70R19, 165 / 55R20, 165 / 55R21, 165 / 60R19, 165 / 65R19, 165 / 70R18, 175 / 55R19, 175 / 55R20, 175 / 55R22, 175 / 60R18, 185 / 55R19, 185 / 60R20, 195 / 50R20, 195 / 55R20.

[0145] The tire of this embodiment can be used as various types of tires classified as passenger car tires, truck and bus tires, two-wheeled vehicle tires, etc. However, among tires that satisfy (Formula 1), it is preferable to apply them to passenger car tires, that is, tires mounted on four-wheeled vehicles with a maximum load capacity of 1000 kg or less. By satisfying (Formula 1), the tire can make a more advantageous contribution to solving the problem of this disclosure (i.e., providing a pneumatic tire that is sufficient to achieve low rolling resistance and handling stability).

[0146] The aforementioned maximum load capacity is a value approximately 50 to 100 kg smaller than the maximum load capacity specified for each tire in the standard system, including the standard on which the tire is based (e.g., the maximum load capacity based on the load index (LI) specified by JATMA standards (Japan Motor Vehicle Tire Association standards)). Specifically, it is calculated using the following two formulas based on the tire section width Wt (mm), tire section height Ht (mm), and tire outer diameter Dt (mm) when the tire is mounted on a standard rim, the internal pressure is set to 250 kPa, and no load is applied. V(mm 3 )={(Dt / 2) 2 -(Dt / 2-Ht) 2}×π×Wt WL (kg) = 0.000011 × V + 175 It should be noted that V is the volume of space occupied by the tire (virtual volume), and (Dt / 2-Ht) is the rim diameter (mm).

[0147] There is no particular limitation on the maximum load capacity as long as it is below 1000 kg. However, as the maximum load capacity increases, the tire weight tends to increase, and correspondingly, the heat generation of the tire tends to increase. Therefore, it is preferably below 900 kg, more preferably below 800 kg, and even more preferably below 700 kg.

[0148] Furthermore, from the perspective of reducing tire heat generation, the tire weight is preferably 20 kg or less, more preferably 15 kg or less, and even more preferably 12 kg or less, 10 kg or less, or 8 kg or less. The term "tire weight" as used herein refers to the weight of the entire tire, and when sealant, sponge, three-dimensional mesh structure, electronic components, etc., are disposed on the inner surface of the tire, the weight includes these components. Additionally, the tire weight can be appropriately adjusted by the thickness and width of the various components constituting the tire, the specific gravity of the rubber composition, the number of steel cords arranged in the belt reinforcement layer, and the structure of the bead wire. [Example]

[0149] The present disclosure will now be described in more detail through examples.

[0150] 1. Manufacturing of rubber compositions for belts First, a rubber composition for belts is prepared.

[0151] (1) Materials First, prepare the following ingredients.

[0152] (a) Rubber composition NR: RSS3

[0153] (b) Compounding materials other than rubber components (b-1) Carbon Black-1: Show Black N326 (N2SA: 78m) manufactured by Cabot Japan Co., Ltd. 2 / g) (b-2) Carbon Black-2: Show Black N550 (N2SA: 42m) manufactured by Cabot Japan Co., Ltd. 2 / g) (b-3) Curing resin component-1: PR12686 (cashew oil modified phenolic resin) manufactured by Sumitomo Bakelite Co., Ltd. (b-4) Curing resin component-2: Sumikanol 620 (modified resorcinol resin) manufactured by Taoka Chemical Industry Co., Ltd. (b-5) Curing agent: Sumikanol 507 (methylene donor) manufactured by Taoka Chemical Co., Ltd. (b-6) Organic cobalt acid: DICNATE NBC-2 manufactured by DIC Corporation (Boron cobalt neodecanoate, cobalt content: 22.5% by mass) (b-7) Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Metals Mining Co., Ltd. (b-8) Antioxidant-1: Nocrac 6C manufactured by Ouchi Shinsei Chemical Co., Ltd. (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) (b-9) Antioxidant-2: Antage RD manufactured by Kawaguchi Chemical Industry Co., Ltd. (2,2,4-Trimethyl-1,2-dihydroquinoline) (b-10) Stearic acid: NOF Corporation's "Tsubaki" stearic acid. (b-11) Crosslinking agents, vulcanization accelerators, crosslinking aids Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator: NOCCELER DZ manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (N,N-Dicyclohexyl-2-benzothiazolylsulfonamide) Crosslinking aid: Duralink HTS manufactured by Flexsys

[0154] (2) Manufacturing of rubber compositions According to the formulations shown in Tables 1 to 4, use a Banbury internal mixer to mix the materials (excluding the curing agent, sulfur, and vulcanization accelerator) at 150°C for 5 minutes to obtain the compound. All proportions are parts by weight.

[0155] Next, the curing agent, sulfur, and vulcanization accelerator are added to the obtained compound, and the mixture is kneaded at 80°C for 5 minutes using a two-roll mill to obtain a rubber composition for belts.

[0156] 2. Tire manufacturing First, steel cords with the structures and outer diameters shown in Tables 1 to 4 are arranged according to the densities (cords / 5cm) shown in Tables 1 to 4. Then, the previously obtained belt rubber composition is coated on both sides to prepare the belt component. At this time, the same amount of rubber is applied to the top and bottom so that the steel cords are aligned in the center of the thickness direction of the belt component; the thickness is appropriately adjusted so that the average distance D (mm) between the steel cords in one pair of belt layers in the vulcanized tire is shown in Tables 1 to 4.

[0157] Then, together with other tire components, the two layers were bonded together such that the steel cords in the belt component crossed each other at the angles shown in Tables 1 to 4, forming an uncured tire. Pressure curing was then performed at 170°C for 10 minutes to produce test tires (Examples 1 to 12 and Comparative Examples 1 to 10) having the dimensions and weights shown in Tables 1 to 4.

[0158] In each of the test tires, the above (L) 80The ratio of L0) is 0.5, the total cross-sectional area of ​​the circumferential grooves is 22% of the cross-sectional area of ​​the tread, and the total volume of the lateral grooves (including lateral grooves with a width / depth of 0.65) is 3.5% of the tread volume.

[0159] 3. Parameter Calculation Then, the outer diameter Dt (mm) and cross-sectional width Wt (mm) of each test tire were determined. Simultaneously, rubber compositions were cut from between the belt layers of each test tire to prepare rubber test pieces with a length of 40 mm and a width of 4 mm for viscoelasticity testing. Using the Eplexor series manufactured by GABO, tanδ and E* were measured at 70°C, a frequency of 10 Hz, an initial strain of 5%, and a dynamic strain of 1%. The results are shown in Tables 1 to 4. For those using the same rubber composition, the viscoelasticity of the rubber composition was measured from each specification, and the average value was calculated and displayed.

[0160] Then, calculate (Dt) 2 ×π / 4) / Wt, [(tanδ / E*) / e]×1000 and [(tanδ / E*)×D]×1000. The results are shown in Tables 1 to 4.

[0161] 4. Performance evaluation test (1) Evaluation of low rolling resistance All test tires were installed on all wheels of the vehicle (a Japanese-made FF vehicle with a 2000cc engine), and air was inflated to a pressure of 250 kPa. The vehicle was then driven at 80 km / h on a dry test track. After 10 km of driving, the accelerator was released, and the distance from when the accelerator was turned off until the vehicle came to a stop was measured.

[0162] Then, the results from Comparative Example 10 were set to 100, and the results were exponentialized based on the following formula to evaluate the low rolling resistance. The larger the value, the longer the distance from when the accelerator is turned off until the vehicle stops in steady state, the smaller the rolling resistance, indicating excellent low rolling resistance and excellent fuel efficiency. Low rolling resistance = [(Results of the test tires) / (Results of Comparative Example 10)] × 100

[0163] (2) Evaluation of handling stability The test tires were installed on all wheels of a Japanese-made FF vehicle (2000cc engine), and inflated to a pressure of 250 kPa. The vehicle was then driven at 40 km / h and 120 km / h on a dry test track. Changes in handling caused by these speed variations were evaluated by drivers using a 5-point scale, ranging from 1 (significant change perceived) to 5 (virtually no change perceived). The total scores from the 20 drivers were then calculated.

[0164] Then, the result from Comparative Example 10 is taken as 100 and exponentialized based on the following formula to evaluate handling stability. The larger the value, the better the handling stability. Handling stability = [(Results of the test tires) / (Results of Comparative Example 10)] × 100

[0165] (3) Comprehensive evaluation The evaluation results of (1) and (2) above are combined to obtain a comprehensive evaluation.

[0166] (4) Evaluation Results The evaluation results are shown in Tables 1 to 4.

[0167] [Table 1]

[0168] [Table 2]

[0169] [Table 3]

[0170] [Table 4]

[0171] According to the results shown in Tables 1 to 4, when the tire has a belt layer (in which a rubber composition is coated on monofilament cords arranged in a pattern of 50 cords / 5cm or more) and satisfies (Equation 1), a pneumatic tire that satisfactorily achieves low rolling resistance and handling stability can be provided.

[0172] Furthermore, it is known that by controlling (Equations 2) to (Equations 6) and by appropriately controlling the outer diameter of the cord, pneumatic tires that further achieve low rolling resistance and handling stability can be provided.

[0173] Although the present disclosure has been described above based on embodiments, the present disclosure is not limited to the embodiments described above. Various modifications can be made to the embodiments described above within the same and equivalent scope as the present disclosure.

[0174] This disclosure (1) is: A pneumatic tire having a tread and a belt layer, wherein, The reinforcing cords in the belt layer are composed of monofilament cords, which are arranged at least 50 cords per 5cm in the tire's radial cross-section and in the tire width direction; and The cross-sectional width Wt (mm) and outer diameter Dt (mm) of a tire mounted on a standard rim with an internal pressure of 250 kPa satisfy the following (Equation 1). 1500≦(Dt 2 ×π / 4) / Wt(Equation 1)

[0175] This disclosure (2) is a pneumatic tire according to this disclosure (1), wherein the pneumatic tire satisfies the following (Equation 2). 1600≦(Dt 2 (×π / 4) / Wt (Equation 2)

[0176] This disclosure (3) is a pneumatic tire according to this disclosure (2), wherein the pneumatic tire satisfies the following (Equation 3). 1700≦(Dt 2 ×π / 4) / Wt(Equation 3)

[0177] This disclosure (4) is an inflatable tire according to any combination of (1) to (3) of this disclosure, wherein the outer diameter of the cord made of monofilament is more than 0.1 mm and less than 0.5 mm.

[0178] This disclosure (5) is an inflatable tire based on any combination of this disclosure (1) to (4), wherein the number of monofilament cords arranged e (cords / 5cm) per 5cm in the tire width direction is 75 cords / 5cm or more.

[0179] This disclosure (6) is a pneumatic tire based on any combination of this disclosure (1) to (5), wherein, In the belt layer, The reinforcing cord is coated with a rubber composition. The complex elastic modulus E* (MPa) of the rubber composition was determined under the following conditions: temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: elongation. The loss tangent (tanδ) of the rubber composition was measured under the following conditions: temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: tensile. The number of reinforcing cords e (cords) arranged every 5 cm in the tire width direction in the tread section satisfies the following (Equation 4). [(tanδ / E*) / e]×1000≦0.2 (Formula 4)

[0180] This disclosure (7) is a pneumatic tire according to this disclosure (6), wherein the pneumatic tire satisfies the following (Equation 5). [(tanδ / E*) / e]×1000≦0.12 (Formula 5)

[0181] This disclosure (8) is a pneumatic tire according to this disclosure (6) or (7), wherein (tanδ / E*) is 0.002 or more and 0.017 or less.

[0182] This disclosure (9) is an inflatable tire according to any combination of this disclosure (1) to (8), wherein at least two belt layers are provided, and in at least one group of belt layers that are adjacent in the radial direction of the tire, the average distance D (mm) between the cords in each belt layer in the tread portion is less than 0.6 mm.

[0183] This disclosure (10) is an inflatable tire according to any combination of (1) to (9) of this disclosure, wherein at least two belt layers are provided; in at least one group of belt layers adjacent in the radial direction of the tire, the angle formed by the cords in each belt layer in the tread portion in the circumferential direction of the tire is 65° or less.

[0184] This disclosure (11) is an inflatable tire according to any combination of disclosures (1) to (10), wherein at least two belt layers are provided; In at least one group of belt layers that are adjacent in the radial direction of the tire, The complex elastic modulus E* (MPa) of the rubber composition with coated reinforcing cord was determined under the following conditions: temperature: 70℃, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: elongation. The loss tangent (tanδ) of the rubber composition used to coat and reinforce the cord was measured under the following conditions: temperature: 70℃, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: tensile. The average distance D (mm) between the cords in each belt layer of the tread portion satisfies the following (Equation 6). (tanδ / E*)×D×1000≦8.0 (Formula 6)

[0185] This disclosure (12) is an inflatable tire according to any combination of this disclosure (1) to (11), wherein, in the belt layer, the rubber composition covering the reinforcing cord contains 60 parts by mass or less of carbon black relative to 100 parts by mass of the rubber component.

[0186] This disclosure (13) is a pneumatic tire according to any combination of disclosures (1) to (12), wherein the tread has circumferential grooves extending continuously in the tire circumferential direction, and the groove width L of the circumferential grooves at a depth of 80% of the maximum depth. 80 The ratio of the circumferential groove width L0 on the contact surface of the tread to the groove width L0 (L 80 / L0) is above 0.2 and below 0.7.

[0187] This disclosure (14) is an inflatable tire according to any combination of this disclosure (1) to (13), wherein the tread has a plurality of circumferential grooves extending continuously in the tire circumferential direction, and the total cross-sectional area of ​​the plurality of circumferential grooves is more than 10% and less than 30% of the cross-sectional area of ​​the tread.

[0188] This disclosure (15) is an inflatable tire according to any combination of this disclosure (1) to (14), wherein the tread has a plurality of lateral grooves extending in the tire axial direction, and the total volume of the plurality of lateral grooves is more than 2.0% and less than 5.0% of the volume of the tread.

[0189] This disclosure (16) is an inflatable tire according to any combination of disclosures (1) to (15), wherein the tread has a plurality of lateral grooves extending in the tire axial direction, the plurality of lateral grooves including lateral grooves in which the ratio (Gw / Gd) of groove width Gw to groove depth Gd is 0.50 or more and 0.80 or less.

[0190] This disclosure (17) is an inflatable tire according to any combination of (1) to (16) of this disclosure, wherein the cross-sectional width Wt (mm) of the tire is less than 200mm.

[0191] This disclosure (18) is an inflatable tire according to any combination of the present disclosure (1) to (17), wherein when the outer diameter of the tire is Dt (mm) and the cross-sectional height is Ht (mm), (Dt-2×Ht) is more than 450 (mm) and less than 560 (mm).

[0192] This disclosure (19) is an inflatable tire according to any combination of (1) to (18) of this disclosure, wherein the inflatable tire is a passenger car tire.

Claims

1. A pneumatic tire, said pneumatic tire having a tread and a belt layer, wherein, The reinforcing cords in the belt layer are composed of monofilament cords, which are arranged in a radial cross-section of the belt layer in the tire, with a ratio of e cords / 5cm to at least 50 cords / 5cm in the tire width direction. In the belt layer, the reinforcing cords are coated with a rubber composition. The complex elastic modulus E* MPa of the rubber composition was measured under the following conditions: temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: elongation. The loss tangent tanδ of the rubber composition, measured under the conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: tensile, satisfies: (tanδ / E*) is greater than 0.002 and less than 0.

01. tanδ is greater than 0.08 and less than 0.

10. E* is 8.7 or higher and 10.5 or lower. [(tanδ / E*) / e]×1000≦0.12; The cross-sectional width Wt mm and outer diameter Dt mm of a tire mounted on a standard rim with an internal pressure of 250 kPa satisfy the following (Equation 1): 1500≦(Dt 2 ×π / 4) / Wt (Equation 1).

2. The pneumatic tire according to claim 1, wherein, The pneumatic tire satisfies the following (Equation 2): 1600≦(Dt 2 ×π / 4) / Wt (Equation 2).

3. The pneumatic tire according to claim 2, wherein, The pneumatic tire satisfies the following (Equation 3): 1700 ≦ ​​(Dt) 2 ×π / 4) / Wt (Equation 3).

4. The pneumatic tire according to any one of claims 1 to 3, wherein, The outer diameter of the curtain made of monofilament is 0.1 mm or more and 0.5 mm or less.

5. The pneumatic tire according to any one of claims 1 to 3, wherein, The number of monofilament cords arranged per 5cm in the tire width direction is more than 75 cords per 5cm.

6. The pneumatic tire according to any one of claims 1 to 3, wherein, It is equipped with at least two belt layers. In at least one group of belt layers in the radially adjacent belt layers of the tire, the average distance D mm between the cords in each belt layer in the tread portion is less than 0.6 mm.

7. The pneumatic tire according to any one of claims 1 to 3, wherein, It is equipped with at least two belt layers; In at least one group of adjacent belt layers in the radial direction of the tire, the angle formed by the cords in each belt layer in the tread portion in the circumferential direction of the tire is less than 65°.

8. The pneumatic tire according to any one of claims 1 to 3, wherein, It is equipped with at least two belt layers; In at least one group of belt layers that are adjacent in the radial direction of the tire, The complex elastic modulus E* MPa of the rubber composition with coated reinforcing cord was measured under the following conditions: temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: elongation. The loss tangent tanδ of the rubber composition used to coat and reinforce the cord was measured under the following conditions: temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10Hz, and deformation mode: tensile. The average distance D mm between the cords in each belt layer of the tread portion satisfies the following (Equation 6). (tanδ / E*)×D×1000≦8.0 (Equation 6).

9. The pneumatic tire according to any one of claims 1 to 3, wherein, In the belt layer, the rubber composition contains less than 60 parts by mass of carbon black relative to 100 parts by mass of the rubber component.

10. The pneumatic tire according to any one of claims 1 to 3, wherein, The tread portion has circumferential grooves that extend continuously in the tire circumferential direction. The groove width L at 80% of the maximum depth of the circumferential groove. 80 The ratio L to the circumferential groove width L0 on the tread contact surface 80 / L0 is above 0.2 and below 0.

7.

11. The pneumatic tire according to any one of claims 1 to 3, wherein, The tread section has multiple circumferential grooves that extend continuously in the tire circumferential direction. The total cross-sectional area of ​​the plurality of circumferential grooves is more than 10% and less than 30% of the cross-sectional area of ​​the tread.

12. The pneumatic tire according to any one of claims 1 to 3, wherein, The tread section has multiple lateral grooves extending axially along the tire. The total volume of the multiple lateral grooves is more than 2.0% and less than 5.0% of the volume of the tread area.

13. The pneumatic tire according to any one of claims 1 to 3, wherein, The tread section has multiple lateral grooves extending axially along the tire. The plurality of transverse grooves include transverse grooves in which the ratio of groove width Gw to groove depth Gd, Gw / Gd, is greater than 0.50 and less than 0.

80.

14. The pneumatic tire according to any one of claims 1 to 3, wherein, The tire's cross-sectional width Wt mm is less than 200 mm.

15. The pneumatic tire according to any one of claims 1 to 3, wherein, When the outer diameter of the tire is Dt mm and the cross-sectional height is Ht mm, (Dt﹣2×Ht) is greater than 450 and less than 560.

16. The pneumatic tire according to any one of claims 1 to 3, wherein, The pneumatic tire is a passenger car tire.

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