Code for tires and tires

Abstract

Provided are a tire cord and a tire with which riding comfort and durability can be maintained and tire manufacturing costs can be reduced. A tire cord 11 is used in a ply 10 of a tire 1. The tire cord contains polyester fibers, and the stress σ1 when the tire cord is subjected to 2.5% elongation is 0.05-0.18N / tex, and the stress σ2 when the same is subjected to 5.0% elongation is 0.09-0.33N / tex.

Description

Technical Field

[0001] The present invention relates to a tire cord and a tire.

Background Art

[0002] Conventionally, various tire cords used for the ply of a tire have been proposed. Further, a nylon fiber cord may be used as the tire cord (see, for example, Patent Document 1 below).

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, there has been a strong demand for reducing the manufacturing cost of tires. For this reason, as the tire cord, relatively inexpensive polyester fibers may be used instead of, or together with, nylon fibers.

[0005] However, since a polyester fiber cord has a higher modulus than a nylon fiber cord, when used as a cord for a ply material of a tire, there is a risk of deteriorating the ride comfort of a vehicle. Further, a polyester fiber cord tends to be inferior in compression fatigue resistance to a nylon fiber cord, and there has been a problem that the strength decreases due to repeated deformation during use in a tire and leads to breakage.

[0006] The present invention has been devised in view of the above problems, and the main object thereof is to provide a tire cord and a tire capable of reducing the manufacturing cost of the tire while maintaining ride comfort and durability.

Means for Solving the Problems

[0007] The present invention relates to a tire cord used for a tire ply, which contains polyester fibers, has a stress at 2.5% elongation of 0.05 to 0.18 N / tex, and a stress at 5.0% elongation of 0.09 to 0.33 N / tex.

[0008] The tire cord of the present invention is preferably a cord for a tread reinforcing ply.

[0009] In the tire cord of the present invention, it is desirable that the stress at 2.5% elongation is 0.15 N / tex or less.

[0010] In the tire cord of the present invention, it is desirable that the stress at 5.0% elongation is 0.21 N / tex or less.

[0011] In the tire cord of the present invention, it is desirable that the twist coefficient is 130 to 250.

[0012] The tire cord of the present invention preferably has at least two filaments twisted together.

[0013] In the tire cord of the present invention, it is desirable that it is composed only of polyester fibers.

[0014] In the tire cord of the present invention, it is desirable that a first filament made of polyester fiber and a second filament made of nylon fiber are twisted together.

[0015] A second aspect of the present invention is a tire including the above-described tire cord.

[0016] In the tire of the present invention, it is desirable that the tire cord is used for a belt ply arranged at an angle of 5° or less with respect to the tire circumferential direction.

[0017] The tire of the present invention includes tread rubber, and it is desirable that the loss tangent tanδ of the tread rubber at 30°C is 0.15 or less.

[0018] The tire of the present invention includes tread rubber, and it is desirable that the loss tangent tanδ of the tread rubber at 30°C is 0.13 or less.

[0019] The tire of the present invention includes tread rubber, and it is desirable that the loss tangent tanδ of the tread rubber at 30°C is 0.11 or less.

[0020] In the tire of the present invention, it is desirable that the product of the loss tangent tanδ of the tread rubber at 30°C and the 2% elongation stress (N / tex) of the tire cord is 0.02 or less.

[0021] The tire of the present invention includes a tread portion, the tread portion includes a crown land portion closest to the tire equator, and it is desirable that the width of the crown land portion in the tire axial direction increases toward the inner side in the tire radial direction.

[0022] In the tire of the present invention, circumferential grooves are provided on both sides of the crown land portion, and it is desirable that the width W2 of the crown land portion in the tire axial direction at the position of 95% of the maximum depth of the circumferential groove is 102% to 115% of the width W1 of the crown land portion in the tire axial direction on the tread surface.

Advantages of the Invention

[0023] The present invention relates to a tire cord used for the ply of a tire, which includes polyester fibers, the stress at 2.5% elongation is 0.05 to 0.18 N / tex, and the stress at 5.0% elongation is 0.09 to 0.33 N / tex.

[0024] Generally, the tire cord used for the ply of a tire stretches with the growth of the outer diameter of the tire due to the tire manufacturing process and the filling of internal pressure during tire use. The inventors specified this elongation amount in the range of 2.5% to 5.0%, and by specifying the stress in this elongation range, it was found that even a relatively inexpensive polyester fiber cord can exhibit the same riding comfort and durability as a nylon fiber tire cord.

[0025] As described above, in the present invention, with the above configuration, it is possible to reduce the manufacturing cost of the tire while maintaining the riding comfort and durability.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Explanation of Reference Numerals

[0027] 1 Tire 10 Ply 11 Tire cord σ1 Stress at 2.5% elongation σ2 Stress at 5.0% elongation

Mode for Carrying Out the Invention

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a meridian cross-sectional view of a tire 1 in which the tire cord of the present embodiment is used. FIG. 1 is a cross-sectional view including the rotation axis of the tire 1 in a normal state. As shown in FIG. 1, the tire 1 of the present embodiment is a pneumatic tire for a passenger car. However, it is not limited to such a mode, and the tire cord of the present embodiment may be used for a heavy-duty tire or a motorcycle tire.

[0029] The "normal state" is a no-load state in which the tire is rim-mounted on a normal rim (not shown) and filled with a normal internal pressure. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in this normal state.

[0030] The "normal rim" is the rim defined for each tire in a standard system including the standards on which the tire is based. For example, in the case of JATMA, it is the "standard rim"; in the case of TRA, it is the "Design Rim"; and in the case of ETRTO, it is the "Measuring Rim".

[0031] The "normal internal pressure" is the air pressure defined for each tire in a standard system including the standards on which the tire is based. In the case of JATMA, it is the "maximum air pressure"; in the case of TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in the case of ETRTO, it is the "INFLATION PRESSURE".

[0032] As shown in FIG. 1, the tire 1 of the present embodiment has a carcass 6. The carcass 6 is composed of, for example, a single carcass ply 6A. The carcass ply 6A includes a carcass cord and a topping rubber covering the carcass cord. The carcass cords are arranged, for example, at an angle of 75 to 90° with respect to the tire circumferential direction. For the carcass cords, organic fiber cords such as nylon, polyester, or rayon are preferably employed.

[0033] The carcass ply 6A has a main body portion 6a and a folded-back portion 6b. The main body portion 6a extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. The folded-back portion 6b is continuous with the main body portion 6a and is folded back around the bead core 5 from the inner side to the outer side in the tire axial direction and extends outward in the tire radial direction.

[0034] In the tread portion 2 of the present embodiment, a tread reinforcing layer 7 is provided. The tread reinforcing layer 7 includes, for example, a belt layer 8. The belt layer 8 includes, for example, two belt plies 8A and 8B. Each of the belt plies 8A and 8B includes, for example, a belt cord inclined with respect to the tire circumferential direction and a topping rubber covering the same. Each belt cord is preferably inclined at an angle of 10 to 45° with respect to the tire circumferential direction.

[0035] The tread reinforcing layer 7 includes, for example, a band layer 9. The band layer 9 is composed of, for example, one band ply 9A. The band ply 9A is composed of band cords arranged at an angle of 5° or less with respect to the tire circumferential direction. In a preferred embodiment, the band ply 9A is configured as a so-called jointless band in which one band cord is wound in the tire circumferential direction.

[0036] The tire cord of the present invention is used for a ply arranged in a tire. The tire cord is preferably for a tread reinforcing ply. As a more preferred embodiment, the tire cord of the present embodiment is used as the band cord of the band ply 9A.

[0037] FIG. 2 is an enlarged perspective view of a ply 10 including the tire cord 11 of the present embodiment. As shown in FIG. 2, the ply 10 is configured by covering a plurality of tire cords 11 with a topping rubber 12.

[0038] The tire cord 11 of the present invention includes polyester fibers, and the stress σ1 at 2.5% elongation is 0.05 to 0.18 N / tex, and the stress σ2 at 5.0% elongation is 0.09 to 0.33 N / tex.

[0039] Generally, the tire cord 11 used for the ply 10 of a tire stretches as the outer diameter of the tire grows due to the tire manufacturing process and internal pressure filling during tire use. As a result of intensive research, the inventors have found that by specifying the amount of stretch at the start of tire use and the stress when this amount of stretch is applied, even a relatively inexpensive polyester fiber cord can approximate the physical properties of a nylon fiber cord during tire use and exhibit a ride comfort and durability equivalent to that of a nylon fiber cord. As a result of various experiments, the inventors have specified the amount of stretch to be in the range of 2.5% to 5.0%, and by specifying the stress within this stretch range, they have completed the present invention. In the present invention, with the above configuration, it is possible to reduce the manufacturing cost of the tire while maintaining ride comfort and durability.

[0040] Polyester means a polycondensate synthesized by subjecting a polyvalent carboxylic acid (dicarboxylic acid) and a polyalcohol (diol) to dehydration condensation to form an ester bond. A polyester fiber is a fiber formed by shaping polyester into a fibrous form.

[0041] In this specification, the stress at 2.5% or 5.0% stretch is measured in accordance with the test method for chemical fiber tire cords of JIS L1017.

[0042] The stress σ1 at 2.5% stretch is desirably 0.15 N / tex or less. The stress σ2 at 5.0% stretch is desirably 0.21 N / tex or less. Such a tire cord 11 helps to exhibit excellent ride comfort.

[0043] The stress σ2 is desirably 1.5 to 2.5 times the stress σ1. Such a tire cord 11 helps to exhibit excellent high-speed durability.

[0044] The total fineness D of the tire cord 11 is, for example, 1500 to 3500 dtex, desirably 2000 to 3000 dtex.

[0045] The tire cord 11 preferably has at least two filaments 15 twisted together. The filament 15 may be a monofilament composed of a single fiber or a multifilament composed of a plurality of fibers. The tire cord 11 of the present embodiment has two polyester monofilaments twisted together. That is, the tire cord 11 of the present embodiment is composed only of polyester fibers. Note that "the tire cord is composed only of polyester fibers" means that the entity that exhibits the function of the cord is composed only of polyester fibers and does not contain other fibers, and does not exclude the inclusion of incidental components (for example, an adhesive, etc.).

[0046] The number of twists N1 per 100 mm of the cord is, for example, 20 to 60 times, preferably 30 to 50 times.

[0047] As a coefficient indicating the degree of twist, a twist coefficient Nd can be mentioned. In this specification, the twist coefficient Nd is a value obtained by multiplying the number of twists N2 (times) per 10 mm of the twist coefficient cord by the square root of the total fineness D (dtex). The twist coefficient Nd of the tire cord 11 of the present embodiment is preferably 130 or more, more preferably 140 or more, preferably 250 or less, and more preferably 240 or less. Such a tire cord 11 helps to enhance the ride comfort and durability in a well-balanced manner.

[0048] From the same viewpoint, in the present embodiment, the number of cords driven in per 5 cm of the ply width, that is, the number of ends, is set to 40 to 60.

[0049] Figure 3 shows an enlarged perspective view of the tire cord 11 according to another aspect of the present invention. As shown in Figure 3, the tire cord 11 of this embodiment is formed by twisting a first filament 16 made of polyester fiber and a second filament 17 made of nylon fiber (colored in Figure 3 for easy understanding). Such a tire cord 11 can exhibit performance similar to that of a nylon fiber cord while reducing costs. Note that the first filament 16 and the second filament 17 of this embodiment are monofilaments, respectively, but they may be multifilaments.

[0050] It is desirable that the fineness D1 of the first filament 16 is larger than the fineness D2 of the second filament 17. Specifically, the fineness D1 is 101% - 105% of the fineness D2. Thereby, an excellent cost reduction effect can be expected.

[0051] As shown in Figure 1, the tread portion 2 includes the crown land portion 20 closest to the tire equator C. The tread portion 2 of this embodiment includes two crown land portions 20 sandwiching the tire equator C. In another embodiment, the crown land portion 20 may be arranged on the tire equator C. Further, circumferential grooves 21 extending continuously in the tire circumferential direction are provided on both sides of the crown land portion 20. Since a large contact pressure acts on this crown land portion 20 and the amount of deformation during running is large, it is considered that heat is easily generated.

[0052] Figure 4 shows an enlarged cross-sectional view of the crown land portion 20. As shown in Figure 4, it is desirable that the width of the crown land portion 20 in the tire axial direction increases toward the inner side in the tire radial direction. Thereby, the heat on the tread surface of the crown land portion 20 is easily diffused, and it becomes difficult for the heat to be transmitted to the cord of the band layer 9 (shown in Figure 1). Such an action is considered to improve the durability of the band layer 9 in a tire to which the above-described cord is applied, suppress unnecessary shrinkage of the cord, and enable excellent riding comfort to be exhibited over a long period of time.

[0053] While ensuring the rubber volume of the crown land portion 20, in order to exhibit the above-described effects, the tire axial width W2 of the crown land portion 20 at the position of the depth d2 which is 95% of the maximum depth d1 of the circumferential groove 21 is preferably 102% or more, more preferably 105% or more, still more preferably 107% or more, and preferably 115% or less, more preferably 113% or less, still more preferably 111% or less of the tire axial width W1 of the crown land portion 20 on the tread surface.

[0054] As shown in FIG. 1, the tread portion 2 of the present embodiment includes a tread rubber 2A that forms a tread ground contact surface 2a. When the heat generation property of the tread rubber 2A decreases, the heat transmitted to the cord becomes smaller, and an improvement in the durability of the tread portion 2 and an improvement in the riding comfort can be expected. For this reason, the loss tangent tanδ of the tread rubber 2A at 30°C is preferably 0.15 or less, more preferably 0.13 or less, still more preferably 0.11 or less. On the other hand, if the heat generation property of the tread rubber 2A is excessively low, there is a possibility that the grip performance may not be sufficiently exhibited. From such a viewpoint, the loss tangent tanδ of the tread rubber 2A at 30°C is preferably 0.06 or more, more preferably 0.07 or more, and still more desirably 0.08 or more.

[0055] The complex elastic modulus E* of the tread rubber 2A at 30°C is, for example, 4.5 to 10.0 MPa, and desirably 5.3 to 7.6 MPa. Such a tread rubber 2A improves the handling stability and the riding comfort in a well-balanced manner.

[0056] The loss tangent tanδ and the complex elastic modulus E* of the tread rubber 2A at 30°C are values measured using a dynamic viscoelasticity measuring device (Iplex series) manufactured by GABO in accordance with the provisions of JIS-K6394 under the following conditions. Initial strain: 5% Amplitude of dynamic strain: ±1% Frequency: 10 Hz Deformation mode: Tension Measurement temperature: 30°C

[0057] In the present invention, it is preferable that the product of the loss tangent tanδ of the tread rubber 2A at 30°C and the elongation stress (N / tex) at 2% elongation of the tire cord 11 of the present invention is 0.02 or less. By reducing both the stress at 2% elongation and the heat generation property of the tread rubber so as to satisfy such a relationship, it is possible to prevent heat from being transmitted from the tread portion while maintaining the riding comfort performance, and thus it is considered that the durability performance during high-speed driving can be easily improved at the same time. Further, the product of the loss tangent of the tread rubber and the stress at 2% elongation is preferably 0.017 or less, more preferably 0.15 or less, and even more preferably 0.013 or less.

[0058] Examples of the rubber component used for the tread rubber 2A include diene rubbers such as natural rubber (NR), isoprene rubbers such as isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), and butyl rubber (IIR). From the viewpoint of durability performance, it is preferable to use natural rubber (NR), butadiene rubber (BR), and styrene-butadiene rubber (SBR) for the tread rubber 2A. These may be used alone or in combination of two or more different rubber components.

[0059] The content of SBR in 100 parts by mass of the rubber component used for the tread rubber 2A is preferably more than 5 parts by mass, more preferably more than 50 parts by mass. On the other hand, as the upper limit of the content of SBR, 100 parts by mass or less is preferable, 65 parts by mass or less is more preferable, and 60 parts by mass or less is even more preferable. By setting it within such a range, the effects of the present embodiment can be more easily obtained. The weight average molecular weight of SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content of SBR is preferably more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 20% by mass. On the other hand, from the viewpoints of heat generation property and durability performance, the upper limit of the styrene content of SBR 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 amount (1,2-bond butadiene unit amount) of SBR is, for example, more than 5% by mass and less than 70% by mass. Incidentally, the structure identification (measurement of styrene content and vinyl bond amount) of SBR can be performed, for example, using an apparatus of the JNM-ECA series manufactured by JEOL Ltd.

[0060] SBR is not particularly limited. For example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), etc. can be used. SBR may be either non-modified SBR or modified SBR.

[0061] As the modified SBR, it may be SBR having a functional group that interacts with a filler such as silica. For example, a terminal-modified SBR (terminal-modified SBR having a functional group at the terminal) in which at least one terminal of SBR is modified with a compound (modifying agent) having a functional group, a main-chain modified SBR having a functional group in the main chain, a main-chain terminal-modified SBR having functional groups in the main chain and at the terminal (for example, a main-chain terminal-modified SBR having a functional group in the main chain and at least one terminal modified with a modifying agent), a terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or an epoxy group introduced therein, etc. may be mentioned.

[0062] Examples of such functional groups include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, an epoxy group, etc. Note that these functional groups may have substituents.

[0063] In addition, as the modified SBR, for example, SBR modified with a compound (modifying agent) represented by the following Chemical Formula 1 can be used.

[0064]

Chemical Formula

[0065] In Chemical Formula 1, R1, R2, and R3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or derivatives thereof. R4 and R5 are the same or different and represent a hydrogen atom or an alkyl group. R4 and R5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0066] As the modified SBR modified with the compound (modifying agent) represented by this chemical formula, SBR in which the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) is modified with the compound represented by this chemical formula (modified SBR described in JP-A-2010-111753, etc.) can be used.

[0067] As R1, R2 and R3, an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms) is suitable. As R4 and R5, an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is suitable. n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Further, when R4 and R5 are bonded to form a ring structure together with the nitrogen atom, a 4- to 8-membered ring is preferred. Note that the alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0068] Specific examples of the modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane and the like. These may be used alone or in combination of two or more.

[0069] In addition, as the modified SBR, modified SBR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(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 and other sulfide group-containing silane compounds; 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, 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-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;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, N-phenyl-β-propiolactam; in addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylenebis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethyl ethyleneurea, 1,3-divinyl ethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. The modification with this compound (modifying agent) can be carried out by a known method.;

[0070] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd. and the like can be used. Note that the SBR may be used alone or in combination of two or more kinds.;

[0071] The content (total content) of the isoprene rubber in 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 25 parts by mass or more, and further preferably 35 parts by mass or more from the viewpoint of obtaining good low heat generation property and durability during high-speed driving. On the other hand, the upper limit of the content of the isoprene rubber is not particularly limited, but from the viewpoint of wet grip performance, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and further preferably 50 parts by mass or less. Examples of the isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR and the like.;

[0072] As the NR, for example, those common in the tire industry such as SIR20, RSS#3, and TSR20 can be used. The IR is not particularly limited, and for example, those common in the tire industry such as IR2200 can be used. As the modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. can be used. As the modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be used. As the modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be used. These may be used alone or in combination of two or more.

[0073] The rubber composition used for the tread rubber 2A may further contain BR as required. In this case, from the viewpoint of abrasion resistance, for example, the content of BR in 100 parts by mass of the rubber component is preferably more than 5 parts by mass. On the other hand, the upper limit of the content of BR is not particularly limited, but is preferably 100 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. The weight average molecular weight of BR is, for example, more than 100,000 and less than 2,000,000. The vinyl bond amount of BR is, for example, more than 1% by mass and less than 30% by mass. The cis amount of BR is, for example, more than 1% by mass and less than 98% by mass. The trans amount of BR is, for example, more than 1% by mass and less than 60% by mass.

[0074] BR is not particularly limited, and BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. BR may be either unmodified BR or modified BR, and examples of the modified BR include those modified BR into which the above-mentioned functional groups are introduced. These may be used alone or in combination of two or more. Note that the cis content can be measured by infrared absorption spectroscopy.

[0075] As the BR, for example, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used.

[0076] In addition, the rubber composition of the tread rubber 2A may contain, as other rubber components, rubbers (polymers) generally used in the production of tires, such as nitrile rubber (NBR).

[0077] In this embodiment, the rubber composition of the tread rubber 2A preferably contains a filler. Specific fillers include, for example, silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. Among these, silica and carbon black can be preferably used as reinforcing agents. When using silica, it is preferably used in combination with a silane coupling agent.

[0078] The rubber composition of the tread rubber 2A preferably contains silica. The BET specific surface area of the silica is preferably more than 140 m 2 / g from the viewpoint of obtaining good durability performance, and more preferably more than 160 m 2 / g. On the other hand, from the viewpoint of obtaining good rolling resistance during high-speed driving, it is preferably less than 250 m 2 / g, and more preferably less than 220 m 2 / g. This BET specific surface area is the value of N2SA measured by the BET method in accordance with ASTM D3037-93.

[0079] When using silica as the filling and reinforcing agent, the content of silica relative to 100 parts by mass of the rubber component is preferably more than 35 parts by mass, and more preferably more than 40 parts by mass from the viewpoint of obtaining good durability performance. On the other hand, from the viewpoint of obtaining good rolling resistance, the upper limit of the silica content is preferably less than 70 parts by mass, more preferably less than 65 parts by mass, and even more preferably less than 60 parts by mass.

[0080] Examples of silica include dry-process silica (anhydrous silica), wet-process silica (hydrous silica), etc. Among these, wet-process silica is preferred because it has more silanol groups.

[0081] As the silica, for example, products of Degussa, Rhodia, Tosoh Silica Corporation, Solvay Japan Ltd., Tokuyama Corporation, etc. can be used.

[0082] The rubber composition of the tread rubber 2A preferably contains a silane coupling agent together with silica. The silane coupling agent is not particularly limited, and examples thereof include sulfur-based 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-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,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT and NXT-Z manufactured by Momentive; vinyl-based such as vinyltriethoxysilane, vinyltrimethoxysilane; amino-based such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane; glycidoxy-based such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane; nitro-based such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane; chloro-based such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane. These may be used alone or in combination of two or more.

[0083] As the silane coupling agent, for example, products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Toray Dow Corning Co., Ltd. etc. can be used.

[0084] The content of the silane coupling agent is, for example, more than 3 parts by mass and less than 25 parts by mass with respect to 100 parts by mass of silica.

[0085] The rubber composition of the tread rubber 2A preferably contains carbon black. The content of carbon black is, for example, more than 1 part by mass and less than 200 parts by mass with respect to 100 parts by mass of the rubber component.

[0086] The carbon black is not particularly limited, and examples include furnace black (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF and ECF; acetylene black (acetylene carbon black); thermal black (thermal carbon black) such as FT and MT; channel black (channel carbon black) such as EPC, MPC and CC; graphite and the like. These may be used alone or in combination of two or more.

[0087] The nitrogen adsorption specific surface area (N2SA) of the carbon black is, for example, more than 30 m 2 / g and less than 250 m 2 / g. The dibutyl phthalate (DBP) absorption amount of the carbon black is, for example, more than 50 ml / 100 g and less than 250 ml / 100 g. The nitrogen adsorption specific surface area of the carbon black is measured according to ASTM D4820-93, and the DBP absorption amount is measured according to ASTM D2414-93.

[0088] The specific carbon black is not particularly limited, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nippon Chemical Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. These may be used alone or in combination of two or more.

[0089] In addition to carbon black and silica, the rubber composition of the tread rubber 2A may further contain fillers generally used in the tire industry, such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. The content of these is, for example, more than 0.1 part by mass and less than 200 parts by mass with respect to 100 parts by mass of the rubber component.

[0090] The rubber composition of the tread rubber 2A may contain oil (including extender oil) or liquid rubber as a softening agent. The total content of these is preferably more than 5 parts by mass with respect to 100 parts by mass of the rubber component. As the upper limit of the total content, less than 70 parts by mass is preferable, less than 50 parts by mass is more preferable, and less than 30 parts by mass is even more preferable. Note that the content of the oil also includes the amount of oil contained in the rubber (oil-extended rubber).

[0091] Examples of the oil include mineral oil (generally referred to as process oil), vegetable oil and fat, or a mixture thereof. As the mineral oil (process oil), for example, paraffinic process oil, aromatic process oil, naphthenic process oil, etc. can be used. Examples of the vegetable oil and fat 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, tung oil, etc. These may be used alone or in combination of two or more.

[0092] As specific process oils (mineral oils), for example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Corporation, Oryzoi Co., Ltd., H&R Co., Toyokuni Sekiyu Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd. and the like can be used.

[0093] The liquid rubber mentioned as the softening agent is a polymer in a liquid state at normal temperature (25°C) and is a polymer having the same monomers as solid rubber as constituent elements. Examples of the liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0094] Examples of the liquid diene-based polymer include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like.

[0095] The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the liquid diene-based polymer is, for example, more than 1.0×10 3 super, 2.0×10 5 less than. In this specification, the Mw of the liquid diene-based polymer is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

[0096] As the liquid rubber, for example, products of Kuraray Co., Ltd., Kray Valley Co., Ltd. and the like can be used.

[0097] Further, the rubber composition of the tread rubber 2A preferably contains a resin component as necessary. The resin component may be solid or liquid at normal temperature. Specific resin components include resin components such as styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic-based resins, and two or more thereof may be used in combination. The content of the resin component is preferably more than 2 parts by mass and less than 45 parts by mass, more preferably less than 30 parts by mass, based on 100 parts by mass of the rubber component.

[0098] Styrene resins are polymers using styrene-based monomers as constituent monomers, and examples include polymers obtained by polymerizing a styrene-based monomer as a main component (50% by mass or more). Specific styrene resins include homopolymers obtained by polymerizing each of styrene-based monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) alone, copolymers obtained by copolymerizing two or more styrene-based monomers, and copolymers of a styrene-based monomer and other monomers copolymerizable therewith.

[0099] Examples of other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, acrylics, unsaturated carboxylic acids such as methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene, butadiene, and isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof; and the like.

[0100] As the coumarone resin, coumarone-indene resin is preferably used. Coumarone-indene resin is a resin containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyl toluene, and the like.

[0101] The content of the coumarone-indene resin is, for example, more than 1.0 part by mass and less than 50.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0102] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mg KOH / g and less than 150 mg KOH / g. The OH value represents the amount of potassium hydroxide in milligrams required to neutralize acetic acid bound to hydroxyl groups when 1 g of the resin is acetylated, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0103] The softening point of the coumarone-indene resin is, for example, more than 30 °C and less than 160 °C. The softening point is measured with a ring and ball softening point measuring device according to the softening point defined in JIS K 6220-1:2001, and is the temperature at which the ball drops.

[0104] Examples of terpene resins include polyterpenes, terpene phenols, and aromatic-modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are hydrocarbons represented by the composition of (C5H8) n and their oxygen-containing derivatives, and are compounds having a terpene as a basic skeleton, such as monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ), etc. Examples include α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-farnesene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0105] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc., which are made from the above-mentioned terpene compounds as raw materials, and hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing terpene compounds and phenolic compounds, and resins obtained by hydrogenating the resins. Specific examples of terpene phenols include resins obtained by condensing terpene compounds, phenolic compounds, and formalin. Examples of phenolic compounds include phenol, bisphenol A, cresol, xylenol, etc. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the resins. The aromatic compounds are not particularly limited as long as they have an aromatic ring. 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; coumarone, indene, etc.

[0106] The "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of the C5 fraction include petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, and isoprene. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0107] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which may be hydrogenated or modified. Examples of the C9 fraction include petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. As specific examples, for instance, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resins are preferably used. Among the aromatic vinyl resins, due to economic reasons, ease of processing, and excellent heat generation properties, a homopolymer of α-methylstyrene or styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As the aromatic vinyl resin, for example, those commercially available from companies such as Kraton Corporation and Eastman Chemical Company can be used.

[0108] "C5C9 resin" refers to a resin obtained by copolymerizing a C5 fraction and a C9 fraction, which may be hydrogenated or modified. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As the C5C9 resin, for example, those commercially available from Tosoh Corporation, LUHUA Company, etc. can be used.

[0109] The acrylic resin is not particularly limited, and for example, a solventless acrylic resin can be used.

[0110] The solventless acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (the methods described in U.S. Patent No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Patent No. 5,010,166, TREND 2000, No. 3, pp. 42-45 of the Annual Report of Toagosei Co., Ltd., etc.) without using a polymerization initiator, chain transfer agent, organic solvent, etc. as auxiliary raw materials as much as possible. In the present invention, "(meth)acrylic" means methacrylic and acrylic.

[0111] Examples of monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (such as alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0112] In addition, as monomer components constituting the acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, etc. may be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0113] The acrylic resin may be a resin composed only of (meth)acrylic components or a resin having components other than (meth)acrylic components as constituent elements. Also, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, etc.

[0114] Examples of resin components 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, Nippon Paint Co., Ltd., Nippon Catalyst Co., Ltd., JX Energy Co., Ltd., Arakawa Chemical Industries, Ltd., Tago Chemical Industries Co., Ltd., etc.

[0115] The rubber composition of the tread rubber 2A preferably contains an anti-aging agent. The content of the anti-aging agent is, for example, more than 1 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0116] Examples of the anti-aging agent include 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; p-phenylenediamine-based anti-aging agents 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 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; bis, tris, polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane, etc. These may be used alone or in combination of two or more.

[0117] Note that as the anti-aging agent, products of companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., and Flexsys can be used, for example.

[0118] The rubber composition of the tread rubber 2A may contain stearic acid. The content of stearic acid is, for example, more than 0.5 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component. As stearic acid, conventionally known ones can be used, and for example, products of companies such as NOF Corporation, Kao Corporation, Fuji Film Wako Pure Chemical Corporation, and Chiba Fatty Acids Co., Ltd. can be used.

[0119] The rubber composition of the tread rubber 2A may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 parts by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component. As zinc oxide, conventionally known ones can be used, and for example, products of companies such as Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusuitech Co., Ltd., Sho-Doh Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd. can be used.

[0120] The rubber composition of the tread rubber 2A preferably contains wax. The content of the wax is, for example, 0.5 to 20 parts by mass, preferably 1.0 to 15 parts by mass, more preferably 1.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0121] The wax is not particularly limited, and examples include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as vegetable waxes and animal waxes; and synthetic waxes such as polymers of ethylene, propylene, and the like. These may be used alone or in combination of two or more.

[0122] In addition, as the wax, for example, products of Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. can be used.

[0123] The rubber composition of the tread rubber 2A preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent is, for example, more than 0.1 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0124] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc. generally used in the rubber industry. These may be used alone or in combination of two or more.

[0125] In addition, as the sulfur, for example, products of Tsuruimi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Corporation, Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0126] Examples of crosslinking agents other than sulfur include sulfur-containing vulcanizing agents such as Tackiol V200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6 - hexamethylene - dithiolsulfate dihydrate) manufactured by Flexsys, KA9188 (1,6 - bis(N,N'-dibenzylthiocarbamoyldithio)hexane) manufactured by Lanxess, and organic peroxides such as dicumyl peroxide.

[0127] The rubber composition of the tread rubber 2A preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0128] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyldisulfide, and N-cyclohexyl-2-benzothiazylsulfenamide; 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-benzothiazole sulfenamide, N-t-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diorthotolylguanidine, and orthotolylbiguanidine. These may be used alone or in combination of two or more.

[0129] In addition to these components, the rubber composition of the tread rubber 2A may further contain additives generally used in the tire industry, such as fatty acid metal salts, carboxylic acid metal salts, and organic peroxides. The content of these additives is, for example, more than 0.1 parts by mass and less than 200 parts by mass with respect to 100 parts by mass of the rubber component.

[0130] As described above, the particularly preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments and can be implemented in various forms. Therefore, although not shown in the above embodiments, for example, a sponge for noise absorption and a sealant for puncture prevention may be provided on the inner cavity surface of the tire to which the tire cord of the present invention is applied.

Examples

[0131] The tire cords of the present invention were used for the band ply to manufacture pneumatic tires of size 215 / 60R16. As a comparative example, similar pneumatic tires were manufactured using tire cords that do not meet the specific inventive features of the present invention for the band ply. The compression fatigue resistance and raw material cost of each tire cord, as well as the high-speed durability and ride comfort of the test tires, were tested. The test methods are as follows.

[0132] <Compression fatigue resistance of tire cord> Based on the test method of the disk fatigue strength (Goodrich method) of JIS L1017, the compression and flexure durability rates of each tire cord were measured under the following conditions. The results are expressed as an index with the compression and flexure durability rate of Comparative Example 1 being 100, and the larger the numerical value, the better the compression fatigue resistance. Elongation rate: 1% Compression rate: 0.8% Rotation speed: 2500 rpm Time: 5 hours Temperature: 80 °C

[0133] <High-speed durability> For each test tire, a high-speed durability test was conducted and evaluated according to the method specified in JIS 4230:1998. The results are expressed as an index with the high-speed durability of Comparative Example 1 being 100, and the larger the numerical value, the better the high-speed durability. Mounting rim: 16 × 6.5J Internal pressure: 210 kPa

[0134] <Ride comfort> The ride comfort when the following test vehicle was driven on an asphalt road surface at 80 km / h was evaluated by the driver's sensory evaluation. The results are expressed as a score with the ride comfort of Comparative Example 1 being 100, and the larger the numerical value, the better the ride comfort. Displacement: 2000 cc Drive method: FF Test tire mounting position: All wheels

[0135] <Raw material cost of tire cord> The raw material cost of the tire cord was shown. The results are in terms of an index with the raw material cost of Comparative Example 1 set as 100, indicating that the smaller the numerical value, the lower the raw material cost. The test results are shown in Tables 1 to 4.

[0136]

Table 1

[0137]

Table 2

[0138]

Table 3

[0139]

Table 4

[0140] Note that the tread rubber formulations A to D shown in Tables 1 to 4 are as shown in Table 5 below.

[0141]

Table 5

[0142] As shown in Tables 1 to 4, it was confirmed that the tire cord of the example can reduce the raw material cost while maintaining ride comfort and durability, thus reducing the manufacturing cost of the tire. Further, it was confirmed that the tire using the tire cord of the present invention has further improved high-speed durability and ride comfort by stipulating the loss tangent at 30°C of the tread rubber and the width in the tire axial direction of the crown land portion, etc.

Claims

1. A tire cord used for the ply of a tire, comprising polyester fibers, having a stress at 2.5% elongation of 0.05 to 0.06 N / tex, having a stress at 5.0% elongation of 0.09 to 0.14 N / tex, formed by twisting together a first filament made of polyester fibers and a second filament made of nylon fibers, a tire cord.

2. The tire cord according to claim 1, which is a cord for a tread reinforcing ply.

3. The tire cord according to claim 1 or 2, having a twist coefficient of 130 to 250.

4. A tire comprising the tire cord according to any one of claims 1 to 3.

5. Comprising tread rubber, The tire according to claim 4, wherein the complex elastic modulus E* of the tread rubber at 30°C is 4.5 to 5.3 MPa.

6. The tire according to claim 5, wherein the loss tangent tanδ of the tread rubber at 30°C is 0.15 or less.

7. The tire according to claim 5, wherein the loss tangent tanδ of the tread rubber at 30°C is 0.13 or less.

8. The tire according to claim 5, wherein the loss tangent tanδ of the tread rubber at 30°C is 0.11 or less.

9. A tire comprising a tire cord used for the ply of a tire, wherein the tire cord comprises polyester fibers, has a stress at 2.5% elongation of 0.05 to 0.18 N / tex, has a stress at 5.0% elongation of 0.09 to 0.33 N / tex, is formed by twisting together a first filament made of polyester fibers and a second filament made of nylon fibers, comprises tread rubber, wherein the complex elastic modulus E* of the tread rubber at 30°C is 4.5 to 5.3 MPa, and the loss tangent tanδ of the tread rubber at 30°C is 0.11 or less, a tire.

10. The tire according to claim 9, wherein the tire cord is a cord for a tread reinforcing ply.

11. The tire according to claim 9 or 10, wherein the stress at 2.5% elongation is 0.15 N / tex or less.

12. The tire according to any one of claims 9 to 11, wherein the stress at 5.0% elongation is 0.21 N / tex or less.

13. Having a stress at 2.5% elongation of 0.05 to 0.06 N / tex, The tire according to any one of claims 9 to 12, wherein the stress at 5.0% elongation is 0.09 to 0.14 N / tex.

14. The tire according to any one of claims 9 to 13, wherein the twist coefficient of the tire cord is 130 to 250.

15. The tire according to any one of claims 5 to 14, wherein the tire cord is used for a belt ply arranged at an angle of 5° or less with respect to the tire circumferential direction.

16. The tire according to any one of claims 5 to 15, wherein the product of the loss tangent tanδ of the tread rubber at 30°C and the elongation stress (N / tex) at 2% elongation of the tire cord is 0.02 or less.

17. including a tread portion, the tread portion includes a crown land portion closest to the tire equator, The tire according to any one of claims 4 to 16, wherein the width of the crown land portion in the tire axial direction increases toward the inner side in the tire radial direction.

18. Circumferential grooves are provided on both sides of the crown land portion, The tire according to claim 17, wherein the width W2 of the crown land portion in the tire axial direction at a position 95% of the maximum depth of the circumferential groove is 102% to 115% of the width W1 of the crown land portion in the tire axial direction on the tread surface.

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