Tire cord and tire

Abstract

Provided are a tire cord and tire that can reduce tire manufacturing costs while maintaining ride comfort and durability. The tire cord 11 is used in the carcass ply 10 of a tire 1. The tire cord comprises polyester fiber, and has a stress σ1 of 0.05 to 0.18 N / tex at 2.5% elongation and a stress σ2 of 0.09 to 0.33 N / tex at 5.0% elongation.

Description

Technical Field

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

[0002] So far, about the tire cord used in the carcass layer of tire, people have proposed various schemes.In addition, as tire cord, there is the situation (for example, with reference to following patent documentation 1) using nylon fiber cord.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-120981 Summary of the Invention

[0004] Problems to be solved by the invention

[0005] In recent years, there has been a strong desire to reduce tire manufacturing costs. Therefore, relatively inexpensive polyester fibers are sometimes used as tire cords instead of, or in addition to, nylon fibers.

[0006] However, polyester fiber cords have a higher modulus than nylon fiber cords, and therefore, when used in tire ply materials, they can impair vehicle ride comfort. Furthermore, polyester fiber cords tend to have lower compression fatigue resistance than nylon fiber cords, leading to reduced strength and even breakage due to repeated deformation caused by use in tires.

[0007] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to provide a tire cord and a tire that can reduce tire manufacturing costs while maintaining ride comfort and durability.

[0008] Means of solving problems

[0009] The present invention is a tire cord for a tire ply, wherein the tire cord contains polyester fiber, and the stress of the tire cord at 2.5% stretching is 0.05-0.18N / tex, and the stress of the tire cord at 5.0% stretching is 0.09-0.33N / tex.

[0010] Preferably, the tire cord of the present invention is a cord for a tread reinforcing ply.

[0011] Preferably, in the tire cord of the present invention, the stress at 2.5% elongation is 0.15 N / tex or less.

[0012] Preferably, in the tire cord of the present invention, the stress at 5.0% elongation is 0.21 N / tex or less.

[0013] Preferably, in the tire cord of the present invention, the twist coefficient is 130-250.

[0014] Preferably, in the tire cord of the present invention, at least two filaments are twisted together.

[0015] Preferably, the tire cord of the present invention is composed only of polyester fibers.

[0016] Preferably, in the tire cord of the present invention, first filaments composed of polyester fibers and second filaments composed of nylon fibers are twisted together.

[0017] A second aspect of the present invention is a tire including the above-mentioned tire cord.

[0018] Preferably, in the tire of the present invention, the tire cord is used in a belt ply arranged at an angle of 5° or less with respect to the tire circumferential direction.

[0019] Preferably, the tire of the present invention includes a tread rubber having a loss tangent tan δ at 30° C. of 0.15 or less.

[0020] Preferably, the tire of the present invention includes a tread rubber having a loss tangent tan δ at 30° C. of 0.13 or less.

[0021] Preferably, the tire of the present invention includes a tread rubber having a loss tangent tan δ at 30° C. of 0.11 or less.

[0022] Preferably, in the tire of the present invention, the product of the loss tangent tanδ of the tread rubber at 30°C and the value of the 2% elongation stress (N / tex) of the tire cord is 0.02 or less.

[0023] Preferably, the tire of the present invention includes a tread portion including a crown land portion closest to the tire equator, wherein the tire axial width of the crown land portion increases toward the inner side in the tire radial direction.

[0024] Preferably, in the tire of the present invention, circumferential grooves are provided on both sides of the crown land portion, and the axial width W2 of the crown land portion at a position of 95% of the maximum depth of the circumferential groove is 102% to 115% of the axial width W1 of the crown land portion on the tread.

[0025] Effects of the Invention

[0026] The present invention is a tire cord for a tire cord layer, the tire cord contains polyester fiber, the stress of the tire cord when stretched by 2.5% is 0.05-0.18N / tex, and the stress of the tire cord when stretched by 5.0% is 0.09-0.33N / tex.

[0027] Tire cords, typically used in tire plies, stretch as the tire's outer diameter grows due to factors such as the tire's manufacturing process and internal pressure during use. The inventors discovered that by limiting this stretch to a range of 2.5% to 5.0%, and thus limiting the stress within this stretch range, relatively inexpensive polyester fiber cords can achieve ride comfort and durability comparable to nylon fiber tire cords.

[0028] As described above, in the present invention, by virtue of the above-mentioned configuration, it is possible to reduce tire manufacturing costs while maintaining ride comfort and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] [ Figure 1 ]A meridian cross-sectional view of a tire using the tire cord according to this embodiment.

[0030] [ Figure 2 ] An enlarged oblique view of a ply of tire cords containing the present embodiment.

[0031] [ Figure 3 ]An enlarged oblique view of a tire cord according to another embodiment of the present invention.

[0032] [ Figure 4 ] An enlarged cross-sectional view of the crown land portion of this embodiment.

[0033] [reference numerals]

[0034] 1 tire

[0035] 10-ply

[0036] 11Tire cord

[0037] σ1 Stress at 2.5% elongation

[0038] σ2 Stress at 5.0% tension DETAILED DESCRIPTION

[0039] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0040] Figure 1 It is a meridian cross-sectional view of a tire 1 using the tire cord according to the present embodiment. Figure 1 : is a cross-sectional view of the tire 1 in a normal state including the rotation axis. Figure 1 As shown, the tire 1 of this embodiment is a pneumatic tire for a passenger car. However, the tire cord of this embodiment is not limited to this mode, and can also be used for a heavy-duty tire or a tire for a two-wheeled vehicle.

[0041] The "normal state" refers to the unloaded state in which the tire is assembled on a normal rim (not shown) and filled to a normal internal pressure. Unless otherwise specified, the dimensions of various parts of the tire are values ​​measured in this normal state.

[0042] A "regular rim" is a rim specified for each tire in the specification system including the specifications on which the tire is based, such as "standard rim" in JATMA, "design rim" in TRA, and "measuring rim" in ETRTO.

[0043] "Normal internal pressure" is the air pressure specified for each tire in the specification system that includes the specifications on which the tire is based. In JATMA, it is the "maximum air pressure", in TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is "INFLATION PRESSURE".

[0044] like Figure 1 As shown, the tire 1 of this embodiment includes a carcass 6. The carcass 6 is composed, for example, of a single carcass ply 6A. The carcass ply 6A includes carcass cords and a topping rubber covering the carcass cords. The carcass cords are arranged, for example, at an angle of 75 to 90 degrees relative to the tire circumferential direction. Suitable carcass cords include organic fiber cords such as nylon, polyester, or rayon.

[0045] The carcass ply 6A includes a main portion 6a and a turnback portion 6b. The main portion 6a extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. The turnback portion 6b is connected to the main portion 6a, bypasses the bead core 5, and turns back from the axially inner side to the outer side of the tire, extending radially outward.

[0046] The tread portion 2 of this embodiment is provided with a tread reinforcing layer 7. 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 belt ply 8A and 8B includes, for example, belt cords arranged obliquely with respect to the tire circumferential direction and a topping rubber covering the belt cords. Preferably, each belt cord is inclined at an angle of 10 to 45 degrees with respect to the tire circumferential direction.

[0047] The tread reinforcing layer 7 includes, for example, a belt layer 9. The belt layer 9 is composed, for example, of a single belt ply 9A. The belt ply 9A is composed of belt cords arranged at an angle of 5° or less relative to the tire circumferential direction. In a preferred embodiment, the belt ply 9A is constructed as a so-called seamless belt, in which a single belt cord is wound in the tire circumferential direction.

[0048] The tire cord of the present invention is used for a tire ply provided on a tire. The tire cord is preferably used for a tread reinforcing ply. More preferably, the tire cord of this embodiment is used as a belt cord of a belt ply 9A.

[0049] Figure 2 1 is an enlarged perspective view of a carcass layer 10 including a tire cord 11 according to this embodiment. Figure 2 As shown, the carcass layer 10 is composed of a plurality of tire cords 11 covered with a topping rubber 12 .

[0050] The tire cord 11 of the present invention contains polyester fibers, and has a stress σ1 of 0.05 to 0.18 N / tex at 2.5% elongation and a stress σ2 of 0.09 to 0.33 N / tex at 5.0% elongation.

[0051] The tire cord 11 used in the general tire ply 10 stretches as the tire's outer diameter grows due to factors such as the tire manufacturing process and internal pressure filling during tire use. After extensive research, the inventors discovered that by limiting the amount of stretch at the start of tire use and the stress applied during this stretch, even relatively inexpensive polyester fiber cords can have cord properties similar to those of nylon fiber cords during tire use, achieving the same ride comfort and durability as nylon fiber cords. The inventors' various experiments resulted in the present invention being completed by limiting the stretch to a range of 2.5% to 5.0% and the stress within this stretch range. The present invention, through the aforementioned configuration, can reduce tire manufacturing costs while maintaining ride comfort and durability.

[0052] Polyester refers to a polycondensate synthesized by dehydrating and condensing polycarboxylic acids (dicarboxylic acids) and polyols (diols) to form ester bonds. Polyester fiber is a polyester fiber formed into a fiber.

[0053] In this specification, the stress at 2.5% or 5.0% elongation is measured in accordance with the test method for chemical fiber tire cord of JIS L1017.

[0054] The stress σ1 at 2.5% elongation is preferably 0.15 N / tex or less. The stress σ2 at 5.0% elongation is preferably 0.21 N / tex or less. Such a tire cord 11 contributes to excellent ride comfort.

[0055] The stress σ2 is preferably 1.5 to 2.5 times the stress σ 1. Such a tire cord 11 contributes to the excellent high-speed durability.

[0056] The total fineness D of the tire cord 11 is, for example, 1500 to 3500 dtex, or preferably 2000 to 3000 dtex.

[0057] In the tire cord 11, at least two filaments 15 are preferably twisted together. The filament 15 can be a monofilament formed by one fiber, or a multifilament formed by a plurality of fibers. In the tire cord 11 of this embodiment, two monofilaments formed by polyester are twisted together. That is, the tire cord 11 of this embodiment is composed only of polyester fibers. In addition, "the tire cord is composed only of polyester fibers" means that the entity that performs the function of the cord is composed only of polyester fibers and does not contain other fibers, and does not exclude the presence of incidental components (such as adhesives, etc.).

[0058] The number of twists N1 per 100 mm of the cord is, for example, 20 to 60 times, preferably 30 to 50 times.

[0059] An example of a coefficient indicating the degree of twist is the twist coefficient Nd. In this specification, the twist coefficient Nd is the value obtained by multiplying the number of twists (N2) per 10 mm of the twist cord by the square root of the total fineness D (dtex). The twist coefficient Nd of the tire cord 11 of this embodiment is preferably 130 or greater, more preferably 140 or greater, and preferably 250 or less, more preferably 240 or less. Such a tire cord 11 contributes to a well-balanced improvement in ride comfort and durability.

[0060] Based on the same viewpoint, in this embodiment, the number of cords inserted per 5 cm width of the carcass layer, that is, the end density (ends) is 40 to 60.

[0061] Figure 3 FIG. 1 is an enlarged perspective view showing another embodiment of a tire cord 11 of the present invention. Figure 3 As shown, in the tire cord 11 of this embodiment, a first filament 16 formed of a polyester fiber and a second filament 17 formed of a nylon fiber are twisted (for ease of understanding, Figure 3 Such tire cord 11 can reduce costs while exerting performance similar to that of nylon fiber cord. In addition, the first filament 16 and the second filament 17 of this embodiment are each monofilament, but may also be multifilament.

[0062] Preferably, 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% to 105% of the fineness D2. This can achieve excellent cost reduction effects.

[0063] like Figure 1As shown, the tread portion 2 includes a 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 other embodiments, the crown land portion 20 may be located on the tire equator C. Furthermore, circumferential grooves 21 extending continuously in the tire circumferential direction are provided on both sides of the crown land portion 20. These crown land portions 20 are subjected to high ground pressure and deform significantly during driving, thus easily generating heat.

[0064] Figure 4 : is an enlarged cross-sectional view of the crown land portion 20. Figure 4 As shown, the axial width of the crown land portion 20 is preferably increased toward the inner side of the tire radial direction. As a result, the heat of the tread of the crown land portion 20 is easily diffused, and the heat is difficult to be transmitted to the belt layer 9 ( Figure 1 It is believed that such an effect, when used in a tire in which the above-mentioned cord is used as a belt layer 9, improves the durability of the belt layer 9 while suppressing unnecessary shrinkage of the cord, thereby achieving excellent ride comfort over a long period of time.

[0065] In order to achieve the above-mentioned effect while ensuring the rubber volume of the crown land portion 20, 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 of the tire axial width W1 of the crown land portion 20 on the tread, more preferably 105% or more, further preferably 107% or more, and preferably 115% or less, more preferably 113% or less, further preferably 111% or less.

[0066] like Figure 1 As shown, the tread portion 2 of the present embodiment includes a tread rubber 2A that forms a tread contact surface 2a. When the heat generation of the tread rubber 2A decreases, the amount of heat transmitted to the cords decreases, and it can be expected that the durability of the tread portion 2 and the ride comfort will be improved. Therefore, the loss tangent tanδ of the tread rubber 2A at 30°C is preferably 0.15 or less, more preferably 0.13 or less, and further preferably 0.11 or less. On the other hand, when the heat generation of the tread rubber 2A is too low, the grip performance may not be fully exerted. Based on this 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 further preferably 0.08 or more.

[0067] The complex elastic modulus E* of the tread rubber 2A at 30° C. is, for example, 4.5 to 10.0 MPa, and preferably 5.3 to 7.6 MPa. Such a tread rubber 2A can improve steering stability and ride comfort in a well-balanced manner.

[0068] 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 apparatus (EPLEXOR series) manufactured by GABO Corporation under the following conditions in accordance with JIS-K6394.

[0069] Initial strain: 5%

[0070] Amplitude of dynamic strain: ±1%

[0071] Frequency: 10Hz

[0072] Deformation Mode: Stretch

[0073] Measurement temperature: 30°C

[0074] In the present invention, the product of the loss tangent tanδ of the tread rubber 2A at 30°C and the stress at 2% elongation (N / tex) of the tire cord 11 of the present invention is preferably 0.02 or less. It is believed that by reducing both the stress at 2% elongation and the heat generation of the tread rubber to achieve this relationship, heat transfer from the tread portion can be prevented while maintaining ride comfort, thereby easily improving durability during high-speed driving. Furthermore, the product of the loss tangent and the stress at 2% elongation of the tread rubber is preferably 0.017 or less, more preferably 0.15 or less, and even more preferably 0.013 or less.

[0075] Examples of the rubber component used in the tread rubber 2A include isoprene-based rubbers such as natural rubber (NR) and 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). The tread rubber 2A preferably uses natural rubber (NR), butadiene rubber (BR), and styrene-butadiene rubber (SBR) based on durability. These rubber components may be used alone, or two or more different rubber components may be used in combination.

[0076] The content of SBR in 100 parts by mass of the rubber component used in the tread rubber 2A is, for example, preferably greater than 5 parts by mass, more preferably greater than 50 parts by mass. On the other hand, as the upper limit of the content of SBR, it is preferably less than 100 parts by mass, more preferably less than 65 parts by mass, and further preferably less than 60 parts by mass. By setting this content within such a range, it is easier to obtain the effect of the present embodiment. The weight-average molecular weight of SBR is, for example, greater than 100,000 and less than 2,000,000. The styrene content of SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and further preferably greater than 20% by mass. On the other hand, based on the viewpoints of heat-generating properties and durability, the upper limit of the styrene content of SBR is preferably less than 50% by mass, more preferably less than 40% by mass, and further preferably less than 35% by mass. The vinyl bond content (1,2-bound butadiene unit amount) of SBR is, for example, greater than 5% by mass and less than 70% by mass. In addition, the structural identification of SBR (determination of styrene content and vinyl bond content) can be carried out using a device such as the JNM-ECA series manufactured by JEOL Ltd.

[0077] The SBR is not particularly limited, and for example, emulsion-polymerized styrene butadiene rubber (E-SBR), solution-polymerized styrene butadiene rubber (S-SBR), etc. can be used. The SBR may be either unmodified SBR or modified SBR.

[0078] As modified SBR, any SBR having functional groups that can interact with fillers such as silica may be used. Examples include terminal-modified SBR in which at least one terminal of the SBR is modified with a compound (modifier) ​​having the above-mentioned functional group (terminal-modified SBR having the above-mentioned functional group at the terminal), main-chain-modified SBR having the above-mentioned functional group in the main chain, main-chain terminal-modified SBR having the above-mentioned functional group in both the main chain and the terminal (for example, main-chain terminal-modified SBR in which the main chain has the above-mentioned functional group and at least one terminal is modified with the above-mentioned modifier), terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and terminal-modified SBR into which hydroxyl groups or epoxy groups are introduced.

[0079] Examples of such functional groups include amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazole, urea, ether, carbonyl, oxycarbonyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imido, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxy, and epoxy groups. These functional groups may have substituents.

[0080] In addition, as the modified SBR, for example, SBR modified by a compound (modifier) ​​represented by the following Chemical Formula 1 may be used.

[0081] [Chemistry 1]

[0082]

[0083] In addition, in Chemical Formula 1, R 1 、R 2 and R 3 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 a derivative thereof. 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. 4 and R 5 It can combine with nitrogen to form a ring structure. n represents an integer.

[0084] As the modified SBR modified with the compound (modifier) ​​represented by the chemical formula, there can be used SBR obtained by modifying the polymerization ends (active ends) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the chemical formula (such as the modified SBR described in Japanese Patent Application Laid-Open No. 2010-111753).

[0085] As R 1 、R 2 and R 3 , preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). 4 and R 5 , is preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and further preferably 3. 4 and R 5 When combined with a nitrogen atom to form a ring structure, a 4- to 8-membered ring is preferred. In addition, the alkoxy group also includes cycloalkoxy groups (such as cyclohexyloxy) and aryloxy groups (such as phenoxy and benzyloxy).

[0086] Specific examples of the modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These modifiers may be used alone or in combination of two or more.

[0087] In addition, as modified SBR, modified SBR modified with the following compounds (modifiers) can also be used. Examples of the modifier include polyglycidyl ethers of polyols 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 diglycidyl bisphenol A; polyepoxides such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl Diglycidylamino compounds such as oleyl-4-glycidyloxyaniline, diglycidyl o-toluidine, tetraglycidyl methylxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino-containing acid chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, N,N-diethylcarbamoyl chloride; 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyl) Silane compounds containing epoxy groups 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-(tripropoxysilyl) propyl] sulfide, Silane compounds containing a thioether group, such as (trimethylsilyl) [3-(methyldipropoxysilyl)propyl] sulfide and (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; 4-N,N-dimethylaminobenzophenone Benzaldehyde compounds having an amino group and / or a substituted amino group, such as formaldehyde, 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-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone; -substituted piperidones; N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam and other N-substituted lactams; other 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-dimethylethyleneurea, 1,3-divinylethyleneurea, 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, etc. In addition, modification by the compound (modifier) ​​can be carried out according to a known method. ;

[0088] As SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used.

[0089] The content (total content) of the isoprene-based 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 even more preferably 35 parts by mass or more, from the perspective of achieving good low heat buildup and durability during high-speed driving. On the other hand, the upper limit of the isoprene-based rubber content is not particularly limited, but from the perspective of wet grip performance, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 50 parts by mass or less. Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR.

[0090] Examples of NR include SIR20, RSS#3, and TSR20, which are commonly used in the tire industry. IR is not particularly limited, and examples of conventional tire industry products include IR2200. Modified NR includes deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Modified NR includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Modified IR includes epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0091] The rubber composition used in the tread rubber 2A may further contain BR as needed. In this case, the BR content in 100 parts by mass of the rubber component is preferably greater than 5 parts by mass, for example, from the perspective of wear resistance. On the other hand, there is no particular upper limit on the BR content, but it 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, greater than 100,000 and less than 2,000,000. The vinyl bond content of BR 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.

[0092] BR is not particularly limited, and BR with a high cis content (90% or more cis content), BR with a low cis content, and BR containing syndiotactic polybutadiene crystals can be used. Examples of BR include unmodified BR and modified BR. Modified BR includes BR introduced with the aforementioned functional groups. These can be used alone or in combination of two or more. The cis content can be measured by infrared absorption spectroscopy.

[0093] As BR, for example, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used.

[0094] The rubber composition of the tread rubber 2A may contain, as other rubber components, a rubber (polymer) commonly used in tire manufacturing, such as nitrile rubber (NBR).

[0095] In this embodiment, the rubber composition of the tread rubber 2A preferably contains a filler. Specific fillers include silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. Among them, silica and carbon black are preferably used as reinforcing agents. When silica is used, it is preferably used in combination with a silane coupling agent.

[0096] The rubber composition of the tread rubber 2A preferably contains silica. The BET specific surface area of ​​silica is preferably greater than 140 m 2 / g, more preferably greater than 160m 2 On the other hand, from the perspective of obtaining good rolling resistance during high-speed running, it is preferably less than 250 mm 2 / g, more preferably less than 220m 2 The BET specific surface area is a value of N2SA measured by the BET method according to ASTM D3037-93.

[0097] When silica is used as a filler and reinforcing agent, the silica content relative to 100 parts by mass of the rubber component is preferably greater than 35 parts by mass, and more preferably greater than 40 parts by mass, from the perspective of achieving good durability. On the other hand, from the perspective of achieving 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.

[0098] Examples of silica include dry-process silica (anhydrous silica), wet-process silica (hydrous silica), etc. Among these, wet-process silica is preferred because it contains many silanol groups.

[0099] As silica, for example, products of Degussa, Rhodia, Tosoh Silica Corporation, Solvay Japan Ltd., Tokuyama Co., Ltd., and the like can be used.

[0100] 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 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, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(2-triethoxysilylethyl ...butyl)tetrasulfide, bis(2-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulf bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, Sulfide-based silanes such as methyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based silanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; vinyl-based silanes such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silanes such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based silanes such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chlorine-based silanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. These may be used alone or in combination of two or more.

[0101] As the silane coupling agent, for example, products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., AZMAX Co., Ltd., Dow Corning Toray Industries, Ltd., and the like can be used.

[0102] The content of the silane coupling agent relative to 100 parts by mass of silica is, for example, greater than 3 parts by mass and less than 25 parts by mass.

[0103] The rubber composition of the tread rubber 2A preferably contains carbon black. The content of the carbon black is, for example, greater than 1 part by mass and less than 200 parts by mass per 100 parts by mass of the rubber component.

[0104] The carbon black is not particularly limited, and examples thereof include furnace blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black; thermal blacks such as FT and MT; channel blacks such as EPC, MPC, and CC; and graphite. These may be used alone or in combination of two or more.

[0105] The nitrogen adsorption specific surface area (N2SA) of carbon black is, for example, greater than 30 m 2 / g, less than 250m 2 / g. The dibutyl phthalate (DBP) absorption of carbon black is, for example, greater than 50 ml / 100 g and less than 250 ml / 100 g. Furthermore, the nitrogen adsorption specific surface area of ​​carbon black is measured in accordance with ASTM D4820-93, and the DBP absorption of carbon black is measured in accordance with ASTM D2414-93.

[0106] Specific carbon blacks are not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nichika Carbon Co., Ltd., and Columbia Carbon. These may be used alone or in combination of two or more.

[0107] The rubber composition of the tread rubber 2A may contain, in addition to carbon black and silica, common materials used in the tire industry, such as fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. The content of these fillers is, for example, greater than 0.1 parts by mass and less than 200 parts by mass per 100 parts by mass of the rubber component.

[0108] The rubber composition of the tread rubber 2A may contain oil (including extender oil), liquid rubber, and other softeners. The total content of these agents is preferably greater than 5 parts by mass per 100 parts by mass of the rubber component. The upper limit of the total content is preferably less than 70 parts by mass, more preferably less than 50 parts by mass, and even more preferably less than 30 parts by mass. The oil content also includes the amount of oil contained in the rubber (oil-extended rubber).

[0109] As oil, for example, mineral oil (commonly referred to as process oil), vegetable oil or its mixture can be mentioned. As mineral oil (process oil), for example, paraffinic process oil, aromatic process oil, naphthenic process oil etc. can be used. As vegetable oil, 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 oil, safflower oil, sesame oil, olive oil, sunflower seed oil, palm kernel oil, tea oil, jojoba oil, macadamia nut oil, tung oil etc. can be mentioned. These can be used alone or in combination of two or more.

[0110] Specific examples of process oils (mineral oils) include products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Nippon Energy Co., Ltd., Olisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Manufacturing Co., Ltd., Showa Shell Sekiyu Co., Ltd., and Fuji Kosan Co., Ltd.

[0111] Liquid rubber as a softener is a polymer that is liquid at room temperature (25° C.) and is composed of the same monomers as solid rubber. Examples of liquid rubber include farnesene polymers, liquid diene polymers, and hydrogenated products thereof.

[0112] Examples of the liquid diene polymer include liquid styrene-butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), and liquid styrene-isoprene copolymers (liquid SIR).

[0113] The weight average molecular weight (Mw) of the liquid diene polymer in terms of polystyrene measured by gel permeation chromatography (GPC) is, for example, greater than 1.0×10 3 , less than 2.0×10 5 In this specification, the Mw of a liquid diene polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0114] As the liquid rubber, for example, products of Kuraray Co., Ltd., Cray Valley Corporation, etc. can be used.

[0115] Furthermore, the rubber composition of the tread rubber 2A preferably contains a resin component as needed. The resin component may be solid or liquid at room temperature. Specific examples of the resin component include styrene resins, coumarone resins, terpene resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins. Two or more resin components may be used in combination. The content of the resin component per 100 parts by mass of the rubber component is preferably greater than 2 parts by mass and less than 45 parts by mass, and more preferably less than 30 parts by mass.

[0116] Examples of the styrene resin include polymers using styrene monomers as constituent monomers, polymers polymerized with styrene monomers as the main component (50% by mass or more), etc. Specific examples of the styrene resin include homopolymers obtained by polymerizing styrene monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.), copolymers obtained by copolymerizing two or more styrene monomers, and copolymers of styrene monomers and other monomers copolymerizable therewith (styrene monomers).

[0117] Examples of other monomers 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, and olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or their anhydrides; and the like.

[0118] 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, methylindene, and vinyltoluene.

[0119] The content of the coumarone indene resin relative to 100 parts by mass of the rubber component is, for example, greater than 1.0 part by mass and less than 50.0 parts by mass.

[0120] The hydroxyl value (OH value) of the coumarone indene resin is, for example, greater than 15 mgKOH / g and less than 150 mgKOH / g. The OH value refers to the amount of potassium hydroxide required to neutralize the acetic acid bound to the hydroxyl groups when 1 g of the resin is acetylated. This value is expressed in milligrams and is measured by potentiometric titration (JIS K 0070:1992).

[0121] The softening point of the coumarone indene resin is, for example, higher than 30° C. and lower than 160° C. The softening point is the temperature at which the ball falls, as measured by a ring and ball softening point measuring apparatus according to JIS K6220-1:2001.

[0122] 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 composed of (C5H8) n The hydrocarbons and their oxygenated derivatives represented by the composition are classified as monoterpenes (C 10 H 16 ), sesquiterpenes (C15 H 24 ), diterpenes (C 20 H 32 ) and the like as the basic skeleton of the compound, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0123] As polyterpenes, in addition to the 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, hydrogenated terpene resins that have been hydrogenated can also be mentioned. As terpene phenols, resins obtained by copolymerizing terpene compounds and phenolic compounds and resins obtained by hydrogenating the resins can be mentioned. As specific terpene phenols, resins obtained by condensing terpene compounds, phenolic compounds and formalin can be mentioned. In addition, phenolic compounds can include phenol, bisphenol A, cresol, xylenol, etc. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds and resins obtained by hydrogenating the resins can be mentioned. In addition, as an aromatic compound, there is no particular limitation as long as it is a compound having an aromatic ring, and examples thereof include phenol 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.

[0124] "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, such as cyclopentadiene, pentene, pentadiene, and isoprene. Dicyclopentadiene resin (DCPD resin) is a suitable C5 petroleum resin.

[0125] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may also be obtained by hydrogenating or modifying the C9 fraction. Examples of the C9 fraction include petroleum fractions corresponding to 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples include coumarone indene resins, coumarone resins, indene resins, and aromatic vinyl resins. As aromatic vinyl resins, for reasons of economy, ease of processing, and excellent heat generation, α-methylstyrene or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As aromatic vinyl resins, for example, commercially available resins from Kraton, Eastman Chemical, etc. can be used.

[0126] "C5C9 resin" refers to a resin obtained by copolymerizing a C5 fraction and a C9 fraction, and may also be obtained by hydrogenating or modifying these fractions. Examples of the C5 and C9 fractions include the aforementioned petroleum fractions. Commercially available C5C9 resins, such as those from Tosoh Corporation and Luhua Corporation, can be used.

[0127] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0128] Examples of solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (described in, for example, U.S. Patent No. 4,414,370, Japanese Patent Application Laid-Open No. 59-6207, Japanese Patent Application Laid-Open No. 5-58005, Japanese Patent Application Laid-Open No. 1-313522, U.S. Patent No. 5,010,166, and Toa Synthesis Research Annual Report TREND 2000, No. 3, pp. 42-45) with minimal use of secondary raw materials such as polymerization initiators, chain transfer agents, and organic solvents. In the present invention, (meth)acrylic acid refers to both methacrylic acid and acrylic acid.

[0129] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0130] As monomer components constituting the acrylic resin, aromatic vinyl groups such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene can be used together with (meth)acrylic acid and (meth)acrylic acid derivatives.

[0131] The acrylic resin may be a resin composed only of a (meth)acrylic component or a resin containing components other than the (meth)acrylic component as constituent elements. The acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0132] As the resin component, for example, products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF Corporation, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., JX Energy Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industry Co., Ltd. can be used.

[0133] The rubber composition of the tread rubber 2A preferably contains an antioxidant. The content of the antioxidant is, for example, greater than 1 part by mass and less than 10 parts by mass per 100 parts by mass of the rubber component.

[0134] Examples of antioxidants include naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4′-bis(α,α′-dimethylbenzyl)diphenylamine; p-phenylenediamine 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 antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroxyquinoline; monophenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; and bisphenol-, triphenol-, or polyphenol-based antioxidants such as tetrakis-[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane. These antioxidants may be used alone or in combination of two or more.

[0135] As the antioxidant, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., FLEXSYS Co., Ltd., and the like can be used.

[0136] The rubber composition of the tread rubber 2A may contain stearic acid. The content of stearic acid per 100 parts by mass of the rubber component may be, for example, greater than 0.5 parts by mass and less than 10.0 parts by mass. Conventionally known stearic acids can be used, such as those produced by NOF Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., and Chiba Fatty Acids Co., Ltd.

[0137] The rubber composition of the tread rubber 2A may contain zinc oxide. The zinc oxide content is, for example, greater than 0.5 parts by mass and less than 10 parts by mass per 100 parts by mass of the rubber component. Conventionally known zinc oxides can be used, such as those produced by Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Shodo Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd.

[0138] 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, and more preferably 1.5 to 10 parts by mass per 100 parts by mass of the rubber component.

[0139] The wax is not particularly limited, and examples thereof include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant wax and animal wax; and synthetic waxes such as polymers of ethylene and propylene. These may be used alone or in combination of two or more.

[0140] As the wax, for example, products of Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., and the like can be used.

[0141] 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, greater than 0.1 parts by mass and less than 10.0 parts by mass per 100 parts by mass of the rubber component.

[0142] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur generally used in the rubber industry. These may be used alone or in combination of two or more.

[0143] As sulfur, for example, products of Tsurumi Chemical Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., FLEXSYS Co., Ltd., Nippon Senryu Industry Co., Ltd., Hosoi Chemical Co., Ltd., and the like can be used.

[0144] Examples of cross-linking agents other than sulfur include sulfur-containing vulcanizing agents such as TACKIROL V200 manufactured by Taoka Chemical Industry Co., Ltd., DURALINK HTS (1,6-hexamethylenedithiosulfate sodium dihydrate) manufactured by FLEXSYS, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane) manufactured by LANXESS, and organic peroxides such as dicumyl peroxide.

[0145] The rubber composition of the tread rubber 2A preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, greater than 0.3 parts by mass and less than 10.0 parts by mass per 100 parts by mass of the rubber component.

[0146] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazolylsulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanizing agents such as N-cyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolylsulfenamide, and N,N'-diisopropyl-2-benzothiazolylsulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide. These may be used alone or in combination of two or more.

[0147] In addition to these components, the rubber composition of the tread rubber 2A may also 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 is, for example, greater than 0.1 parts by mass and less than 200 parts by mass per 100 parts by mass of the rubber component.

[0148] While particularly preferred embodiments of the present invention have been described above, the present invention is not limited to the aforementioned embodiments and can be implemented in various variations. Therefore, although not shown in the aforementioned embodiments, a tire to which the tire cord of the present invention is applied may be provided with a noise-absorbing sponge or a puncture-preventing sealing material, for example, on the inner surface of the tire.

[0149] Example

[0150] A pneumatic tire with a size of 215 / 60R16 was manufactured using the tire cord of the present invention in the belt ply. As a comparative example, a tire cord that does not meet the specific requirements of the present invention was used in the belt ply to manufacture the same pneumatic tire. The compression fatigue resistance and raw material cost of each tire cord were tested, as well as the high-speed durability and ride comfort of the tire. The testing methods are as follows.

[0151] <Compression fatigue resistance of tire cord>

[0152] The compression / bending durability of each tire cord was measured under the following conditions based on the disc fatigue strength test method (Goodrich method) in accordance with JIS L1017. The results were indexed, with the compression / bending durability of Comparative Example 1 being 100. A larger value indicates better compression fatigue resistance.

[0153] Elongation: 1%

[0154] Compression rate: 0.8%

[0155] Speed: 2500rpm

[0156] Time: 5 hours

[0157] Temperature: 80℃

[0158] High-speed durability

[0159] Each test tire was evaluated by a high-speed durability test according to the method specified in JIS 4230: 1998. The results were indexed with the high-speed durability of Comparative Example 1 being 100, with larger values ​​indicating better high-speed durability.

[0160] Installed rim: 16×6.5J

[0161] Internal pressure: 210kPa

[0162] Ride Comfort

[0163] The ride comfort of the test vehicle was evaluated by the sensory evaluation of the driver when the vehicle was traveling at 80 km / h on an asphalt road. The results were scored with the ride comfort of Comparative Example 1 being 100, with larger values ​​indicating better ride comfort.

[0164] Displacement: 2000cc

[0165] Drive mode: FF

[0166] Test tire installation position: All wheels

[0167] <Raw material costs for tire cord>

[0168] The raw material costs of the tire cord are given as indices with the raw material cost of Comparative Example 1 being 100, and smaller values ​​indicate lower raw material costs.

[0169] The test results are shown in Tables 1 to 4.

[0170] [Table 1]

[0171]

[0172] [Table 2]

[0173]

[0174] [Table 3]

[0175]

[0176] [Table 4]

[0177]

[0178] In addition, the formulations A to D of the tread rubber shown in Tables 1 to 4 are shown in Table 5 below.

[0179] [Table 5]

[0180] (Unit: parts by mass)

[0181] A B C D NR 40 40 40 40 SBR(JSR HPR850) 50 50 50 50 BR(BR150B) 10 10 10 10 Carbon black (N220) 15 15 5.0 15 Silica (NIPSIL VN3) 38 45 65 51 Silane coupling agent (NXT) 3.8 4.5 6.5 5.1 Oil (VIVATEC 500) 7.0 10 2.0 12 Resin composition (SYLVATRAXX 4401) 3.0 3.0 3.0 3.0 zinc oxide 3.0 3.0 3.0 3.0 stearic acid 3.0 3.0 3.0 3.0 Wax (WAX) 1.0 1.0 1.0 1.0 Antioxidant (6C) 1.5 1.5 1.5 1.5 Antioxidant (RD) 1.0 1.0 1.0 1.0 sulfur 1.5 1.5 1.5 1.5 Vulcanization accelerator 1 (NS) 2.0 2.0 2.0 2.0 Vulcanization accelerator 2 (DPG) 1.0 1.0 1.0 1.0 Complex elastic modulus at 30℃ (MPa) 5.3 6.0 7.6 6.8 Loss tangent at 30°C 0.11 0.13 0.14 0.15

[0182] As shown in Tables 1 to 4, the tire cords of the Examples can be confirmed to maintain ride comfort and durability while reducing raw material costs, thereby reducing tire manufacturing costs. Furthermore, it can be confirmed that tires using the tire cords of the present invention have limited loss tangent at 30°C of the tread rubber and the axial width of the crown land portion, thereby further improving high-speed durability and ride comfort.

Claims

1. A tire cord for a tire cord layer, characterized in that: The tire cord is a mixture of first filaments made of polyester fibers and second filaments made of nylon fibers. The stress of tire cord at 2.5% stretch is 0.05~0.06N / tex. The stress of the tire cord at 5.0% elongation is 0.09 to 0.14 N / tex.

2. The tire cord according to claim 1, wherein Tire cord is the cord used to reinforce the tread.

3. The tire cord according to claim 1 or 2, characterized in that: The twist coefficient is 130 to 250.

4. A tire, characterized in that: A tire cord according to claim 1 or 2.

5. The tire according to claim 4, characterized in that The tire cord is used in a belt ply arranged at an angle of 5° or less with respect to the tire circumferential direction.

6. The tire according to claim 4, characterized in that Tires contain tread rubber, The tread rubber has a loss tangent tan δ at 30° C. of 0.15 or less.

7. The tire according to claim 4, characterized in that Tires contain tread rubber, The tread rubber has a loss tangent tan δ at 30° C. of 0.13 or less.

8. The tire according to claim 4, characterized in that Tires contain tread rubber, The tread rubber has a loss tangent tan δ at 30° C. of 0.11 or less.

9. The tire according to claim 6, characterized in that The product of the loss tangent tanδ of the tread rubber at 30°C and the value of the 2% elongation stress of the tire cord expressed in N / tex is 0.02 or less.

10. The tire according to claim 4, characterized in that The tire has a tread portion. The tread portion has a crown land portion closest to the tire equator, The tire axial width of the crown land portion increases toward the inner side in the tire radial direction.

11. The tire according to claim 10, characterized in that Circumferential grooves are provided on both sides of the crown land portion. The axial width W2 of the crown land portion at a position where the circumferential groove reaches 95% of its maximum depth is 102% to 115% of the axial width W1 of the crown land portion on the tread.

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