tire

Abstract

To provide a tire which exhibits excellent off-road running-through performance, and can achieve both low fuel consumption performance and abrasion resistance performance.SOLUTION: A tire has a tread composed of a rubber composition containing a rubber component containing 0-50 mass% of an isoprene-based rubber, in which the rubber composition satisfies the following (1) to (3), and the tread satisfies the following (4) to (6). (1) tanδ at 30°C: A≥0.12. (2) Ratio B of elongation at break at 80°C to elongation at break at 23°C: 0.60≤B≤1.00. (3) Abrasion resistance index C with a tire in Comparative Example 1 as 100 measured by LAT test machine: 110≤C≤140. (4) Ratio D of land ratio to whole of a pair of shoulder parts to a land ratio of a crown part: 0.80≤D≤2.00. (5) Maximum groove depth E (mm) in a main groove in a circumferential direction: 5≤E≤20. (6) 25≤(B×C / A)×(D / E)≤200.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire, and more particularly to a tire with excellent off-road performance. [Background technology]

[0002] Tires that are used in harsh regions require high durability, and chipping resistance in particular is highly required. Until now, chipping resistance has been evaluated using indicators such as elongation at break (EB) (%) in tensile tests at room temperature (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-56137 Summary of the Invention [Problem to be solved by the invention]

[0004] However, off-road performance is important for driving in harsh regions, and cannot be fully evaluated by tire rubber properties such as elongation at break (EB) (%) alone. Tires used in harsh regions also require fuel economy and wear resistance, but off-road performance is in a trade-off relationship with these two performances.

[0005] An object of the present invention is to provide a tire that exhibits excellent off-road driving performance while also achieving low fuel consumption and wear resistance. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved in a tire having a tread made of a predetermined rubber composition by specifying the physical properties of the rubber composition of the tread and by specifying the characteristics of the tread pattern, and then adjusting the physical properties and the characteristics of the tread pattern to have a certain relationship. After further research, the present inventors have completed the present invention.

[0007] That is, the present invention is [1] A tire having a tread made of a rubber composition containing a rubber component containing 0 to 50 mass% of an isoprene-based rubber, The rubber composition satisfies the following conditions (1) to (3), (1) Tangent delta (tangent delta) at 30°C 30℃ ) is A, A≧0.12 (2) Elongation at break (EB) at 23°C 23℃ ) at 80℃ vs. elongation at break (EB 80℃ ) ratio (EB 80℃ / EB 23℃ ) is B, 0.60≦B≦1.00 (3) When the abrasion resistance index measured by the LAT tester is C, with the tire of Comparative Example 1 being 100, 110≦C≦140 The tread has a crown portion having a center on the tire equator and a width that is 1 / 3 of the tread contact surface width, and a pair of shoulder portions located on both ends of the crown portion and each having a width that is 1 / 3 of the tread contact surface width, and the crown portion and the shoulder portions satisfy the following condition (4): (4) Land ratio of the crown Cr ) for the entire pair of shoulders (LAND Sh ) ratio (LAND Sh / LAND Cr ) is D, 0.80≦D≦2.00 The tread has at least one circumferential main groove that extends continuously in the tire circumferential direction, and the circumferential main groove satisfies the following condition (5): (5) When the maximum groove depth of the circumferential main groove is E (mm), 5≦E≦20 The following A, B, C, D, and E satisfy the following formula (6): (6) 25 ≤ (B × C / A) × (D / E) ≤ 200 Tire [2] The isoprene rubber is natural rubber, and the tire according to [1] above [3] The rubber composition contains 20 to 70 parts by mass of silica with respect to 100 parts by mass of the rubber component, and the tire according to [1] or [2] above [4] The nitrogen adsorption specific surface area of the silica is 200 m 2 / g or more, and the tire according to [3] above [5] The rubber composition contains 10 to 30 parts by mass of carbon black with respect to 100 parts by mass of the rubber component, and the tire according to any one of [1] to [4] above [6] The nitrogen adsorption specific surface area of the carbon black is 120 to 200 m 2 / g, and the tire according to [5] above [7] The rubber composition contains 2 to 20 parts by mass of a silane coupling agent with respect to 100 parts by mass of silica, and the tire according to any one of [3] to [6] above [8] The rubber composition contains 0.5 to 4.0 parts by mass of a hybrid crosslinking agent with respect to 100 parts by mass of the rubber component, and the tire according to any one of [1] to [7] above [9] D satisfies 0.90 < D < 1.08, and the tire according to any one of [1] to [8] above

[10] The LAND Sh is 60 to 80, and the tire according to any one of [1] to [9] above

[11] Among the pair of shoulder portions, when the land ratio of the shoulder portion on the side where a convex label is provided on the outer surface of the sidewall is defined as stencil LAND Sh and the land ratio of the shoulder portion on the opposite side is defined as non-stencil LAND Sh , stencil LAND Sh < non-stencil LAND Sh , and the tire according to any one of [1] to

[10] above

[12] The circumferential main groove is zigzag or wavy with an amplitude in the tire width direction, and the tire according to any one of [1] to

[11] above

[13] The groove depth of the circumferential main groove is Tread Thickness The tire according to any one of the above [1] to

[12] , wherein the depth is equivalent to 50 to 80% of the above. Regarding. [Effects of the Invention]

[0008] The tire of the present invention exhibits excellent off-road driving performance, and can also achieve low fuel consumption and wear resistance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a development view of a tread pattern for an example tire of the present disclosure. [Figure 2] FIG. 2 is a development view of a tread pattern for an example tire of the present disclosure. [Figure 3] FIG. 2 is a development view of a tread pattern for an example tire of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] A tire according to one embodiment of the present disclosure will be described in detail below. However, the following description is merely an example for explaining the present disclosure, and is not intended to limit the technical scope of the present invention to the described range. In this specification, when a numerical range is indicated using "to," the range includes both ends of the range.

[0011] A tire according to one embodiment of the present disclosure has a tread made of a rubber composition including a rubber component containing 0 to 50% by mass of an isoprene-based rubber, wherein the rubber composition satisfies the following conditions (1) to (3): the tread has a crown portion centered on the tire equator and having a width that is 1 / 3 of the tread contact patch width, and a pair of shoulder portions located on both ends of the crown portion and having a width that is 1 / 3 of the tread contact patch width, the crown portion and the shoulder portions satisfy the following condition (4); the tread has at least one circumferential main groove extending continuously in the tire circumferential direction, the circumferential main groove satisfying the following condition (5); and A, B, C, D, and E satisfy the following formula (6). (1) Tangent delta (tangent delta) at 30°C 30℃ ) is A, A≧0.12 (2) Elongation at break (EB) at 23°C 23℃ ) at 80℃ vs. elongation at break (EB 80℃ ) ratio (EB 80℃ / EB 23℃ ) is B, 0.60≦B≦1.00 (3) When the abrasion resistance index measured by the LAT tester is C, with the tire of Comparative Example 1 being 100, 110≦C≦140 (4) Land ratio of the crown Cr ) for the entire pair of shoulders (LAND Sh ) ratio (LAND Sh / LAND Cr ) is D, 0.80≦D≦2.00 (5) When the maximum groove depth of the circumferential main groove is E (mm), 5≦E≦20 (6) 25≦(B×C / A)×(D / E)≦200

[0012] Without intending to be bound by theory, the tire of the present disclosure achieves excellent off-road performance as well as fuel efficiency and wear resistance, and the reason for this is thought to be as follows. That is, in the tire of the present disclosure, the above A(tan δ 30℃ ), above B(EB 80℃ / EB 23℃), C (wear resistance index), D (LAND Sh / LAND Cr ) and the above E (maximum groove depth) are each within a predetermined range, and furthermore, the product of the value of "B×C / A" consisting of the above A to C relating to the physical properties of the tire's rubber composition and the value of "D / E" consisting of the above D to E relating to the tire's tread pattern is required to fall within a predetermined range. Therefore, the value of "B×C / A" relating to the physical properties of the tire's rubber composition and the value of "D / E" relating to the tire's tread pattern are mutually exclusive and both fall within predetermined ranges, and it is believed that these conditions, combined, contribute to achieving both off-road performance, low fuel consumption, and wear resistance.

[0013] The isoprene-based rubber is preferably natural rubber, as this tends to enhance the effects of the present disclosure.

[0014] The rubber composition preferably contains 20 to 70 parts by mass of silica per 100 parts by mass of the rubber component, whereby the effects of the present disclosure tend to be more pronounced.

[0015] The nitrogen adsorption specific surface area of ​​the silica is 200 m 2 / g or more, the effects of the present disclosure tend to be more pronounced.

[0016] The rubber composition preferably contains 10 to 30 parts by mass of carbon black per 100 parts by mass of the rubber component, which tends to enhance the effects of the present disclosure.

[0017] The nitrogen adsorption specific surface area of ​​the carbon black is 120 to 200 m 2 / g, the effects of the present disclosure tend to be more pronounced.

[0018] The rubber composition preferably contains 2 to 20 parts by mass of a silane coupling agent per 100 parts by mass of silica, which tends to enhance the effects of the present disclosure.

[0019] The rubber composition preferably contains 0.5 to 4.0 parts by mass of a hybrid crosslinking agent with respect to 100 parts by mass of the rubber component. By blending the hybrid crosslinking agent, strong crosslinking chains are formed near the polymer ends, so the chipping resistance performance tends to improve.

[0020] It is preferable that D satisfies 0.90 < D < 1.08. By setting the value of D within such a range, the rigidity difference between the crown portion where a large contact pressure acts and the shoulder portion where a large lateral force acts becomes small, so stable running during straight running and turning is possible, and the handling stability on soft roads and hard roads tends to improve.

[0021] The LAND Sh is preferably 60 to 80. By increasing the rigidity of the shoulder portion where a large lateral force acts, the handling stability tends to improve.

[0022] Among the pair of shoulder portions, the land ratio of the shoulder portion on the side where a convex mark is provided on the outer surface of the sidewall is defined as the stencil LAND Sh and the land ratio of the shoulder portion on the opposite side is defined as the non - stencil LAND Sh When doing so, it is preferable that the stencil LAND Sh < the non - stencil LAND Sh is. Tires are usually mounted with the stencil side facing the outside of the vehicle. By making the land ratio of the shoulder portion different between the stencil side and the non - stencil side in this way, the off - road running performance and the handling stability tend to be compatible. Note that a stencil is a symbol attached to one side of the sidewall portion of an individual tire, representing the manufacturing date, etc.

[0023] The circumferential main groove is preferably zigzag or wavy with an amplitude in the tire width direction. By the circumferential main groove being zigzag or wavy in this way, on both soft roads and hard roads, the road surface can be grasped more accurately, and the handling stability tends to improve.

[0024] The groove depth of the circumferential main groove is Tread ThicknessBy setting the groove depth of the circumferential main groove within this range, the wear life of the tire tends to be extended and chipping can be suppressed.

[0025] [Rubber composition] The rubber composition constituting the tread of the tire of the present disclosure will be described below.

[0026] <Rubber component> From the viewpoint of the effects of the present disclosure, the rubber component of the present disclosure includes a rubber component containing 0 to 50 mass % of an isoprene-based rubber. The rubber component of the present disclosure also includes a rubber component other than the isoprene-based rubber, and examples of such rubber components include styrene-butadiene rubber (SBR) and butadiene rubber (BR).

[0027] (Isoprene rubber) Examples of isoprene-based rubbers that can be used include isoprene rubber (IR) and natural rubber, which are commonly used in the tire industry. Natural rubber includes unmodified natural rubber (NR), as well as modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), highly purified natural rubber (UPNR), and grafted natural rubber. These rubbers may be used alone or in combination of two or more.

[0028] The NR is not particularly limited, and those commonly used in the tire industry can be used, such as SIR20, RSS#3, and TSR20.

[0029] From the viewpoint of the effects of the present disclosure, the content of the isoprene-based rubber in the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. Also, from the viewpoint of the effects of the present disclosure, the content of the isoprene-based rubber is preferably 40% by mass or less, and more preferably 30% by mass or less.

[0030] (SBR) The SBR is not particularly limited, and examples thereof include solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs thereof (modified S-SBR, modified E-SBR). Modified SBRs include SBR whose terminals and / or main chains are modified, and modified SBRs coupled with tin, silicon compounds, etc. (condensates, those having a branched structure, etc.). Of these, S-SBR is preferred. SBRs may be used alone or in combination of two or more.

[0031] Examples of S-SBR that can be used in this embodiment include S-SBR manufactured and sold by JSR Corporation, Sumitomo Chemical Co., Ltd., Ube Industries, Ltd., Asahi Kasei Corporation, and Zeon Corporation.

[0032] The styrene content of SBR is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, because the effects of the present disclosure can be fully obtained. Also, from the viewpoint of good heat buildup, the styrene content is preferably 15% by mass or less, more preferably 13% by mass or less. In this specification, the styrene content of SBR is 1 It is calculated by H-NMR measurement.

[0033] From the viewpoint of good wet grip performance, the vinyl content of SBR is preferably 30 mol% or more, more preferably 33 mol% or more, and even more preferably 35 mol% or more. From the viewpoint of suppressing heat buildup, the vinyl content is preferably 45 mol% or less, preferably 42 mol% or less, and more preferably 40 mol% or less. In this specification, the vinyl content of SBR refers to the number of 1,2-bond units in the butadiene moiety in SBR, and is measured by infrared absorption spectroscopy.

[0034] The weight-average molecular weight (Mw) of SBR is preferably 200,000 or more, more preferably 300,000 or more, even more preferably 400,000 or more, and particularly preferably 500,000 or more, from the viewpoints of abrasion resistance and grip performance. Furthermore, from the viewpoint of crosslink uniformity, Mw is preferably 2,000,000 or less, more preferably 1,000,000 or less. Mw can be determined in terms of standard polystyrene based on measurements obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation).

[0035] From the viewpoint of the effects of the present disclosure, the content of SBR in the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and still more preferably 40% by mass or more. Also, from the viewpoint of suppressing heat buildup, the content of SBR is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and still more preferably 60% by mass or less.

[0036] (BR) The BR is not particularly limited, and can be one commonly used in the tire industry, such as BR with a cis-1,4 bond content of less than 50% (low-cis BR), BR with a cis-1,4 bond content of 90% or more (high-cis BR), rare earth butadiene rubber (rare earth BR) synthesized using a rare earth catalyst, BR containing syndiotactic polybutadiene crystals (SPB-containing BR), or modified BR (high-cis modified BR, low-cis modified BR). Of these BRs, high-cis BR is preferred because of its excellent wear resistance. BRs may be used alone or in combination of two or more.

[0037] Examples of high-cis BR include BR1220 manufactured by Zeon Corporation, BR130B, BR150B, and BR150L manufactured by Ube Industries, Ltd., and BR730 manufactured by JSR Corporation. The inclusion of high-cis BR can improve low-temperature properties and wear resistance. Examples of rare earth BR include BUNA-CB25 manufactured by Lanxess K.K.

[0038] SPB-containing BR is one in which 1,2-syndiotactic polybutadiene crystals are dispersed not simply in BR but are chemically bonded to the BR and then dispersed. Examples of such SPB-containing BR include VCR-303, VCR-412, and VCR-617 manufactured by Ube Industries, Ltd.

[0039] Modified BR includes those obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, in which the terminals of the modified BR molecule are further bonded with tin-carbon bonds (tin-modified BR), and butadiene rubber having a condensed alkoxysilane compound at the active terminal of the butadiene rubber (silica-modified BR). Examples of such modified BR include BR1250H (tin-modified) manufactured by Nippon Zeon Co., Ltd. and S-modified polymer (silica-modified) manufactured by Sumitomo Chemical Co., Ltd.

[0040] From the viewpoint of the effects of the present disclosure, the content of BR in the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and still more preferably 30% by mass or more. From the viewpoint of chipping resistance, the content of BR is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less.

[0041] From the viewpoint of durability and abrasion resistance, the cis-1,4 bond content (cis content) of the BR is preferably 90% by mass or more, more preferably 93% by mass or more, and still more preferably 95% by mass or more. It is believed that a higher cis content leads to a more regularly arranged polymer chain, which strengthens the interaction between polymers and improves rubber strength, thereby improving abrasion resistance when driving on rough roads.

[0042] The weight-average molecular weight (Mw) of the BR is preferably 400,000 or more, more preferably 450,000 or more, and even more preferably 500,000 or more, from the viewpoints of abrasion resistance and grip performance. Furthermore, from the viewpoint of crosslink uniformity, Mw is preferably 2,000,000 or less, more preferably 1,000,000 or less. Mw can be determined by standard polystyrene conversion based on measurements obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation).

[0043] (Other rubber components) The rubber component according to the present disclosure may contain rubber components other than the isoprene-based rubber, SBR, and BR. Examples of other rubber components include crosslinkable rubber components commonly used in the tire industry, such as styrene-isoprene-butadiene copolymer rubber (SIBR), styrene-isobutylene-styrene block copolymer (SIBS), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), ethylene propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), and hydrin rubber. These other rubber components may be used alone or in combination of two or more.

[0044] <Filler> As the filler, those commonly used in the tire industry can be suitably used. Specific examples of such fillers include carbon black and silica. The fillers may be used alone or in combination of two or more.

[0045] (carbon black) As the carbon black, any carbon black commonly used in the tire industry can be used as appropriate, such as GPF, FEF, HAF, ISAF, SAF, etc. These carbon blacks may be used alone or in combination of two or more.

[0046] As carbon black, it has a nitrogen adsorption specific surface area of ​​120m 2 Small particle carbon black with a particle size of 1 / g or more is preferred. By dispersing small particle carbon black near the boundaries between the isoprene rubber, SBR, and BR phases and increasing the contact between the SBR and the carbon black, the bonds between the phases are strengthened, resulting in a rubber composition that can more effectively absorb shocks generated when driving on harsh terrain. Furthermore, the use of small particle carbon black is thought to improve the reinforcing effect of the rubber composition, leading to improved abrasion resistance and chipping resistance.

[0047] The nitrogen adsorption specific surface area (N2SA) of small particle carbon black is 125m from the viewpoint of wear resistance. 2 / g or more is more preferable, and 130m 2 / g or more is more preferable, and 135m 2 The upper limit of the nitrogen adsorption specific surface area is not particularly limited, but from the viewpoint of processability, it is preferable that the upper limit is 200 m 2 / g or less is preferable, and 190m 2 / g or less is more preferable, and 180m 2 The nitrogen adsorption specific surface area can be measured in accordance with JIS K 6217-2 "Carbon black for rubber - Fundamental properties - Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method."

[0048] The amount of carbon black per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, from the viewpoint of abrasion resistance. Also, the amount of carbon black is preferably 55 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less, from the viewpoint of suppressing heat buildup.

[0049] (silica) The silica is not particularly limited, and examples thereof include dry-process silica (silicic anhydride) and wet-process silica (hydrated silicic acid), but wet-process silica is preferred because it contains a large number of silanol groups. Silica may be used alone or in combination of two or more types.

[0050] As silica, the nitrogen adsorption specific surface area (N2SA) is 200m 2 It is preferable to use finely divided silica with a specific surface area of ​​200 m / g or more. The finely divided silica is dispersed near the boundaries between the isoprene rubber, SBR, and BR phases, strengthening the bonds between the phases, resulting in a rubber composition that can more effectively absorb shocks generated when driving on harsh terrain. The use of finely divided silica is also thought to improve the reinforcing effect of the rubber composition, and to improve wear resistance and chipping resistance. The nitrogen adsorption specific surface area of ​​silica is 200 m 2 / g is more preferable, and 205m 2 / g or more is more preferable, and 210m 2 From the viewpoint of fuel economy and processability, the nitrogen adsorption specific surface area of ​​silica is preferably 500 m / g or more. 2 / g or less is preferable, and 300m 2 / g or less is more preferable, and 250m 2 / g or less is more preferable. The nitrogen adsorption specific surface area of ​​silica in this specification is a value measured in accordance with ASTM D3037-93.

[0051] When silica is contained, the content per 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and still more preferably 50 parts by mass or more, from the viewpoint of durability and elongation at break. Also, from the viewpoint of abrasion resistance, the content of silica is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, even more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, and still more preferably 70 parts by mass or less.

[0052] (Silane coupling agent) Silica is preferably used in combination with a silane coupling agent.The silane coupling agent is not particularly limited, and any silane coupling agent that has been conventionally used in combination with silica in the tire industry can be used, for example, the following mercapto-based silane coupling agents: sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide; thioester-based silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, 3-octanoylthio-1-propyltrimethoxysilane; vinyltriethoxysilane, ... Examples of suitable silane coupling agents include vinyl-based silane coupling agents such as methoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, sulfide-based silane coupling agents and / or mercapto-based silane coupling agents are preferred, and mercapto-based silane coupling agents are more preferred. These silane coupling agents may be used alone or in combination of two or more.

[0053] The mercapto-based silane coupling agent is preferably a compound represented by the following chemical formula (1) and / or a compound containing a bonding unit A represented by the following chemical formula (2) and a bonding unit B represented by the following chemical formula (3). [ka] (In the formula, R 101 , R 102 , and R 103are each independently an alkyl having 1 to 12 carbon atoms, an alkoxy having 1 to 12 carbon atoms, or -O-(R 111 -O) z -R 112 (z R 111 each independently represents a divalent hydrocarbon group having 1 to 30 carbon atoms; R 112 represents an alkyl having 1 to 30 carbon atoms, an alkenyl having 2 to 30 carbon atoms, an aryl having 6 to 30 carbon atoms, or an aralkyl having 7 to 30 carbon atoms; z represents an integer of 1 to 30; 104 represents an alkylene having 1 to 6 carbon atoms. [ka] [ka] (wherein x represents an integer of 0 or more; y represents an integer of 1 or more; R 201 represents a hydrogen atom, a halogen atom, an alkyl having 1 to 30 carbon atoms, an alkenyl having 2 to 30 carbon atoms, or an alkynyl having 2 to 30 carbon atoms, which may be substituted with a hydroxyl or carboxyl; R 202 represents an alkylene having 1 to 30 carbon atoms, an alkenylene having 2 to 30 carbon atoms, or an alkynylene having 2 to 30 carbon atoms; 201 and R 202 may form a ring structure with

[0054] Examples of the compound represented by chemical formula (1) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and a compound represented by the following chemical formula (4) (Si363 manufactured by Evonik Degussa), and the compound represented by the following chemical formula (4) can be preferably used. [ka]

[0055] Examples of compounds containing a bonding unit A represented by chemical formula (2) and a bonding unit B represented by chemical formula (3) include NXT-Z30, NXT-Z45, NXT-Z60, and NXT-Z100 manufactured by Momentive Corporation.

[0056] When a silane coupling agent is contained, the content per 100 parts by mass of silica is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, because this provides sufficient effects of improving filler dispersibility, reducing viscosity, etc. Furthermore, the content of the silane coupling agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, because sufficient coupling effect and silica dispersion effect are not obtained, and reinforcing properties are reduced.

[0057] (Other fillers) The other fillers than those mentioned above are not particularly limited, and examples thereof include aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, and talc. These fillers can be used alone or in combination of two or more.

[0058] <Other compounding agents> In addition to the above components, the rubber composition for tread of the present embodiment may contain, as appropriate, compounding agents that are generally used in the production of rubber compositions, such as antioxidants, processing aids, waxes, stearic acid, zinc oxide, softeners, vulcanizing agents, and vulcanization accelerators.

[0059] (anti-aging agent) The antioxidant is not particularly limited, and those used in the rubber field can be used, such as quinoline-based, quinone-based, phenol-based, phenylenediamine-based antioxidants, etc. The antioxidants can be used alone or in combination of two or more.

[0060] When an antioxidant is contained, the content thereof per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, and more preferably 0.8 parts by mass or more, and from the viewpoints of dispersibility of fillers and the like, elongation at break, and kneading efficiency, the content of the antioxidant is preferably 6.0 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0061] (processing aids) Examples of processing aids include fatty acid metal salts such as zinc stearate. Specific examples include fatty acid soap-based processing aids such as EF44 and WB16 manufactured by Struktol. The compounding ratio of the processing aid is preferably 0.1 parts by mass or more, and 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of the total rubber component. The processing aids can be used alone or in combination of two or more.

[0062] (wax) When wax is contained, the content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, from the viewpoint of weather resistance of the rubber, and is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, from the viewpoint of suppressing whitening of the tire due to bloom.

[0063] (stearic acid) When stearic acid is contained, the content per 100 parts by mass of the rubber component is preferably 0.2 parts by mass or more, more preferably 1 part by mass or more, from the viewpoint of vulcanization rate, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of processability.

[0064] (zinc oxide) When zinc oxide is contained, the content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, from the viewpoint of vulcanization rate, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of abrasion resistance.

[0065] (softener) Examples of softeners include oils such as process oils and vegetable oils, liquid diene polymers, resins, and ester-based plasticizers. These softeners may be used alone or in combination of two or more. Of these, oils are preferred.

[0066] Examples of oils include process oils, vegetable oils, and mixtures thereof. Examples of process oils that can be used include paraffin-based process oils, aromatic process oils, and naphthenic process oils. Examples of vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice bran oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. These oils may be used alone or in combination. Examples of oils that can be used include products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Corporation, Oriso Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., and the like.

[0067] The liquid diene polymer is a diene polymer that is in a liquid state at room temperature (25°C). The weight average molecular weight (Mw) of the liquid diene polymer is preferably 3.0 x 10 3 More preferably, 4.0 × 10 3 or more, preferably 1.0 × 10 5 Less than or equal to 1.5 × 10 4 The weight average molecular weight (Mw) in this specification can be determined in terms of standard polystyrene based on measurements obtained using a gel permeation chromatograph (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation).

[0068] Examples of liquid diene polymers include liquid styrene butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), and liquid styrene isoprene copolymers (liquid SIR). These may be used alone or in combination of two or more. Examples of liquid diene polymers that can be used include products from Sartomer, Kuraray Co., Ltd., and the like.

[0069] The resin is not particularly limited as long as it is one commonly used in the tire industry, and examples thereof include rosin-based resins, coumarone-indene resins, α-methylstyrene-based resins, terpene-based resins, pt-butylphenol acetylene resins, acrylic resins, C5 resins, and C9 resins. Commercially available products include those from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., JXTG Nippon Oil & Energy Corporation, Arakawa Chemical Industries, Ltd., Taoka Chemical Co., Ltd., and Toagosei Co., Ltd. These resins may be used alone or in combination of two or more.

[0070] From the viewpoint of the effects of the present disclosure, the softening point of the resin is preferably −45° C. or higher, more preferably 0° C. or higher, even more preferably 30° C. or higher, even more preferably 60° C. or higher, and even more preferably 80° C. or higher. There are no particular limitations on the upper limit of the softening point, but it is preferably 180° C. or lower, more preferably 160° C. or lower, even more preferably 140° C. or lower, and even more preferably 120° C. or lower. The softening point of the resin is the temperature at which the ball drops when the softening point specified in JIS K 6220-1:2001 is measured using a ring and ball softening point tester.

[0071] Examples of the resins that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., JXTG Nippon Oil & Energy Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0072] Examples of ester-based plasticizers include the above-mentioned vegetable oils, synthetic products such as glycerin fatty acid monoesters, glycerin fatty acid diesters, and glycerin fatty acid triesters, and processed vegetable oil products, and phosphoric acid esters (phosphate-based esters, mixtures thereof, etc.). These may be used alone or in combination of two or more.

[0073] The content of the softener per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, from the viewpoint of processability, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of block resistance and abrasion resistance.

[0074] (vulcanizing agent) Suitable vulcanizing agents include sulfur and hybrid crosslinking agents. These may be used alone or in combination of two or more. The incorporation of a hybrid crosslinking agent tends to improve chipping resistance because a strong crosslinked chain is formed near the polymer end.

[0075] Examples of sulfur that can be used include powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. These may be used alone or in combination of two or more. Examples of sulfur that can be used include products from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., and Hosoi Chemical Industry Co., Ltd.

[0076] Examples of hybrid crosslinking agents include alkyl sulfide crosslinking agents and alkylphenol sulfur chloride condensates. These may be used alone or in combination of two or more. Among these, alkyl sulfide crosslinking agents are preferred, and 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane is preferred.

[0077] When sulfur is used as a vulcanizing agent, the content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, from the viewpoint of ensuring a sufficient vulcanization reaction and obtaining good grip performance and abrasion resistance, and is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, from the viewpoint of deterioration.

[0078] When a hybrid crosslinking agent is used as a vulcanizing agent, the content of the hybrid crosslinking agent per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and is preferably 5 parts by mass or less, more preferably 3 parts by mass or less. Within the above range, better effects tend to be obtained.

[0079] When sulfur and a hybrid crosslinking agent are used in combination as a vulcanizing agent, the amount of sulfur per 100 parts by mass of the rubber component is, from the viewpoint of the effects of the present disclosure, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and on the other hand, preferably 1.0 part by mass or less, more preferably 0.8 parts by mass or less. Furthermore, when sulfur and a hybrid crosslinking agent are used in combination as a vulcanizing agent, the amount of the hybrid crosslinking agent per 100 parts by mass of the rubber component is, from the viewpoint of the effects of the present disclosure, preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and even more preferably 1.0 part by mass or more, and on the other hand, preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less.

[0080] Examples of vulcanizing agents other than those mentioned above include vulcanizing agents containing sulfur atoms, such as DURALINK HTS (sodium 1,6-hexamethylenedithiosulfate dihydrate) manufactured by Flexis, and organic peroxides, such as dicumyl peroxide.

[0081] (Vulcanization accelerator) Examples of vulcanization accelerators include sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based or aldehyde-ammonia-based, imidazoline-based, and xanthate-based vulcanization accelerators. These vulcanization accelerators may be used alone or in combination of two or more. Among them, sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, and guanidine-based vulcanization accelerators are preferred, and sulfenamide-based vulcanization accelerators are more preferred.

[0082] Examples of sulfenamide vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), etc. Among these, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS) and N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) are preferred.

[0083] Examples of the thiazole vulcanization accelerator include 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, etc. Among these, 2-mercaptobenzothiazole is preferred.

[0084] Examples of guanidine vulcanization accelerators include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatechol borate, 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, 1,3-di-o-cumenyl-2-propionylguanidine, etc. Among these, 1,3-diphenylguanidine is preferred.

[0085] When a vulcanization accelerator is contained, the content thereof per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, and more preferably 1.0 part by mass or more, from the viewpoint of ensuring a sufficient vulcanization rate, and is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, from the viewpoint of suppressing blooming.

[0086] <Condition (1)> Tan δ of the rubber composition of the present disclosure 30℃ (A) is 0.12 or more. Tan δ is an index of fuel economy, and the smaller its value, the better in terms of fuel economy. In the present disclosure, from the viewpoint of the effects of the present disclosure, tan δ 30℃ (A) is required to be 0.12 or more. 30℃ From the viewpoint of the effects of the present disclosure, the value of (A) is preferably 0.15 or more, and more preferably 0.18 or more. 30℃ The value of (A) is preferably less than 0.25, more preferably 0.24 or less, and even more preferably 0.23 or less. 30℃ is determined by the method described in the Examples section below.

[0087] tanδ 30℃ (A) can be adjusted by conventional methods in the tire industry, by adjusting the types and amounts of chemicals (particularly rubber components, fillers, softeners, sulfur, vulcanization accelerators, and silane coupling agents) compounded in the rubber composition. For example, using a rubber component with fewer unsaturated bonds, using a softener that is highly compatible with the rubber component, using modified rubber, using silica as a filler, reducing oil as a plasticizer, increasing sulfur, increasing the amount of vulcanization accelerators, or increasing the amount of silane coupling agents can all reduce tanδ. 30℃ (A) tends to be small. Therefore, those skilled in the art can determine the target tan δ 30℃ It can be adjusted appropriately depending on the value of (A).

[0088] <Condition (2)> The elongation at break (EB) of the rubber composition of the present disclosure at 23°C 23℃) at 80℃ vs. elongation at break (EB 80℃ ) ratio (EB 80℃ / EB 23℃ The value of EB (=B) is within the range of 0.60≦B≦1.00. Each EB value is an index of the resistance to breakage of the rubber composition at the respective temperature (80°C or 23°C), and the larger the value, the better. In the present disclosure, from the viewpoint of the effects of the present disclosure, EB 23℃ EB against 80℃ The ratio (B) of these is required to be within the range of 0.60≦B≦1.00. From the viewpoint of the effects of the present disclosure, the value of B is preferably 0.70 or more, more preferably 0.80 or more, and even more preferably 0.85 or more. On the other hand, from the viewpoint of the effects of the present disclosure, the value of B is preferably 0.95 or less, and even more preferably 0.93 or less. The values ​​of each EB are determined by the method described in the Examples section below.

[0089] EB 23℃ and E.B. 80℃ The value of can be adjusted by a common method in the tire industry, and can be achieved by adjusting the types and amounts of chemicals (particularly rubber components, fillers, softeners, sulfur, vulcanization accelerators, and silane coupling agents) compounded in the rubber composition. For example, EB 23℃ For example, the value of EB tends to increase when the content of filler is reduced or when the content of softener is increased. 80℃ For example, the value of EB tends to increase as the content of NR increases. 80℃ / EB 23℃ It can be adjusted appropriately depending on the value of (B).

[0090] <Condition (3)> The abrasion resistance index (C) of the rubber composition of the present disclosure, measured using an LAT tester, is 110≦C≦140, with the tire of Comparative Example 1 being taken as 100. Generally, a higher abrasion resistance index is preferable because it indicates better abrasion resistance performance; however, in the present disclosure, from the viewpoint of the effects of the present disclosure, the abrasion resistance index (C) is required to be 110≦C≦140. From the viewpoint of the effects of the present disclosure, the value of the abrasion resistance index (C) is preferably 115 or more, and more preferably 120 or more. Furthermore, from the viewpoint of the effects of the present disclosure, the value of the abrasion resistance index (C) is preferably 135 or less, more preferably 130 or less, and even more preferably 125 or less. The abrasion resistance index value is determined by the method described in the Examples section below.

[0091] The abrasion resistance index (C) can be adjusted by conventional methods in the tire industry, such as by adjusting the types and amounts of chemicals (particularly rubber components, fillers, softeners, sulfur, vulcanization accelerators, and silane coupling agents) compounded in the rubber composition. For example, increasing the content of BR as a rubber component, increasing the content of fillers, or decreasing the content of vulcanizing agents tends to improve abrasion resistance. Therefore, those skilled in the art can appropriately adjust the abrasion resistance index (C) depending on the target value.

[0092] [tire] A tire according to the present disclosure will be described below with reference to the accompanying drawings as appropriate. Note that the tire according to the present disclosure is not limited to the following embodiments.

[0093] The tire of the present disclosure is a tire having a tread made of the above rubber composition, wherein the tread has a crown portion having a center at the tire equator and a width that is 1 / 3 of the tread contact patch width, and a pair of shoulder portions located on both ends of the crown portion and having a width that is 1 / 3 of the tread contact patch width, wherein the crown portion and the shoulder portions satisfy the following condition (4), the tread has at least one circumferential main groove that extends continuously in the tire circumferential direction, and the circumferential main groove satisfies the following condition (5), and A, B, C, D, and E satisfy the following formula (6). (4) Land ratio of the crown Cr ) for the entire pair of shoulders (LAND Sh ) ratio (LAND Sh / LAND Cr ) is D, 0.80≦D≦2.00 (5) When the maximum groove depth of the circumferential main groove is E (mm), 5≦E≦20 (6) 25≦(B×C / A)×(D / E)≦200

[0094] Unless otherwise specified, the dimensions of each part of the tire in this specification are values ​​measured in a normal state, which means that the tire is mounted on a normal rim, inflated to a normal internal pressure, and is not under load.

[0095] "Genuine rim" is the rim specified for each tire by the standard system that includes the standard on which the tire is based, such as "standard rim" for JATMA, "design rim" for TRA, and "measuring rim" for ETRTO. For tire sizes that are not specified in the above standard systems, it refers to the narrowest rim among the smallest diameter rims that can be mounted on the tire and do not cause air leakage between the rim and tire.

[0096] "Normal internal pressure" is the air pressure specified for each tire by each standard, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE." For tire sizes not specified in the above standard systems, the normal internal pressure is 250 kPa.

[0097] The "normal load" is the load determined for each tire by each standard in the standard system including the standard on which the tire is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. For tire sizes not specified in the above standard system, the normal load W L The tire load (kg) can be estimated using the following formulas (1) and (2), where Wt (mm) is the tire section width, Ht (mm) is the tire section height, and Dt (mm) is the tire outer diameter measured under normal conditions. The tire section width Wt is the maximum width between the outer sidewall surfaces under the above conditions, excluding any patterns or letters on the tire sidewalls. The tire section height Ht is the distance from the bottom of the bead portion to the outermost surface of the tread, and is half the difference between the tire outer diameter and the nominal rim diameter. V={(Dt / 2) 2 -(Dt / 2-Ht) 2}×π×Wt (1) W L =0.000011×V+175 (2)

[0098] <Condition (4)> In the tire of the present disclosure, the land ratio of the crown portion (LAND Cr ) for the entire pair of shoulders (LAND Sh ) ratio (LAND Sh / LANDCr =D) is within the range of 0.80≦D≦2.00. Increasing the land ratio can increase the rigidity of the crown and shoulder portions, but in the present disclosure, from the viewpoint of the effects of the present disclosure, it is preferable to keep the difference in land ratio between the crown and shoulder portions within a predetermined range to reduce the difference in rigidity between the two. LAND Sh / LAND Cr The value of (D) is preferably 0.85 or more, more preferably 0.90 or more. More than 0.90 is preferable. Also, LAND Sh / LAND Cr The value of (D) is preferably 1.90 or less, more preferably 1.80 or less, even more preferably 1.70 or less, even more preferably 1.60 or less, even more preferably 1.50 or less, even more preferably 1.40 or less, even more preferably 1.30 or less, even more preferably 1.20 or less, even more preferably 1.10 or less, and even more preferably 1.08 or less. It is preferable that the value is less than 1.08. stomach.

[0099] In this specification, the land ratio is the percentage (%) of the actual total contact area Sb to the total area Sa of the virtual contact patch, including all grooves and sipes (if any). Note that sipes refer to narrow cuts with a width of 2.0 mm or less, preferably 0.5 to 1.5 mm. For example, Figures 1 to 3 are each development views of the tread pattern of an example tire disclosed herein. In Figure 1, the shaded area enclosed by a frame represents the tread surface under normal load. The land ratio of the tread surface is calculated for the entirety of the central crown portion and the pair of shoulder portions located on either side of the crown portion, which are divided by two lines that divide the tread contact patch width TW into thirds. For example, in Figure 1, the land ratio of the crown portion can be calculated to be 66.12%, and the land ratio of the entirety of the pair of shoulder portions can be calculated to be 70.60%. Similarly, in Figure 2, the land ratio of the crown portion can be calculated to be 66.40%, and the land ratio for the entire pair of shoulder portions can be calculated to be 63.84%, and in Figure 3, the land ratio of the crown portion can be calculated to be 42.12%, and the land ratio for the entire pair of shoulder portions can be calculated to be 73.05% (= (71.64% + 74.46%) / 2).In addition, in Figures 1 to 3, the upper side is the stencil side and the lower side is the non-stencil side.

[0100] LAND Cr From the viewpoint of the effects of the present disclosure, is preferably 40 or more, more preferably 45 or more, and is preferably 70 or less, more preferably 65 or less.

[0101] LAND Sh is preferably 45 or more, more preferably 50 or more, from the viewpoint of the effects of the present disclosure, More preferably, it is 60 or more, On the other hand, it is preferably 80 or less, and more preferably 75 or less.

[0102] <Condition (5)> In the tire of the present disclosure, the maximum groove depth (E) (mm) of the circumferential main groove is in the range of 5≦E≦20. The maximum groove depth of the circumferential main groove originally affects the balance between steering stability on dry road surfaces and wet grip performance, but in the present disclosure, it is adjusted to a predetermined range from the viewpoint of the effects of the present disclosure. The maximum groove depth (E) of the circumferential main groove is preferably 6 mm or more, more preferably 7 mm or more, and even more preferably 8 mm or more. Furthermore, the maximum groove depth (E) of the circumferential main groove is preferably 18 mm or less, more preferably 15 mm or less, and even more preferably 13 mm or less.

[0103] <Formula (6)> In the tire of the present disclosure, the A(tanδ 30℃ ), the B(EB 80℃ / EB 23℃ ), C (wear resistance index), D (LAND Sh / LAND Cr ) and the aforementioned E (maximum groove depth), the value represented by (B × C / A) × (D / E) is within the range of 25≦(B × C / A) × (D / E)≦200. 30℃ ), above B(EB 80℃ / EB 23℃ ) and the above C (wear resistance index) are values ​​relating to the physical properties of the rubber composition of the tread, while the above D (LAND Sh / LAND Cr ) and the above E (maximum groove depth) are values ​​related to the tread pattern.

[0104] In the tire of the present disclosure, the product of the value of "B×C / A" consisting of the above A to C related to the physical properties of the rubber composition of the tread and the value of "D / E" consisting of the above D to E related to the tread pattern is required to be within the range of 25 to 200.Therefore, it is believed that the effects of the present disclosure are achieved by the value of "B×C / A" related to the physical properties of the rubber composition of the tread and the value of "D / E" related to the tread pattern both regulating each other and ultimately falling within the specified ranges.

[0105] The value shown by (B×C / A)×(D / E) is preferably 26 or more, more preferably 35 or more, even more preferably 45 or more, and even more preferably 55 or more. In addition, the value shown by (B×C / A)×(D / E) is preferably 190 or less, more preferably 180 or less, and even more preferably 175 or less.

[0106] (Stencil LAND Sh and non-stencil LAND Sh ) In the tire of the present disclosure, the land ratio of the shoulder portion on the side where the convex mark is provided on the outer surface of the sidewall of the pair of shoulder portions is set to stencil LAND Sh The land ratio of the shoulder on the opposite side is set to non-stencil LAND Sh And when you go to Stencil Land Sh <NON-STENCIL LAND Sh This is because, normally, by increasing the land ratio of the shoulder portion on the non-stencil side, which is the inside of the vehicle, there is a tendency to achieve both off-road performance and handling stability.

[0107] (Circumferential main groove configuration) In the tire of the present disclosure, the circumferential main groove preferably has a zigzag or wavy shape with amplitude in the tire width direction. Here, "zigzag" refers to a state in which the center line of the circumferential main groove has multiple bends and the bends have edge components in the tire width direction. Furthermore, "wavy" refers to a state in which the center line of the circumferential main groove meanders in a wavy pattern. In either case, the center line of the circumferential main groove has amplitude in the tire width direction. The circumferential main grooves in FIG. 1 and FIG. 2 are examples of zigzag grooves. On the other hand, the circumferential main groove in FIG. 3 is not zigzag but linear. A zigzag or wavy circumferential main groove can more accurately grip the road surface, even on soft or hard roads, and tends to improve handling stability.

[0108] (Depth of circumferential main groove) In the tire of the present disclosure, the circumferential main groove has a groove depth of mainThe depth is preferably 50 to 80% of the distance (F) from the tread surface position in the groove portion toward the tire radially inward to the tread edge. By setting the groove depth of the circumferential main groove within this range, the tire wear life tends to be extended and chipping can be suppressed. The groove depth of the circumferential main groove is preferably 55% or more of the distance F, more preferably 60% or more. Furthermore, the groove depth of the circumferential main groove is preferably 75% or less of the distance F, more preferably 70% or less.

[0109] [Tire manufacturing] The tire of the present disclosure can be manufactured by a general method, for example, by kneading the components other than the crosslinking agent and vulcanization accelerator among the above-mentioned components in a known kneading machine generally used in the tire industry, such as a Banbury mixer, a kneader, or an open roll, and then adding the crosslinking agent and vulcanization accelerator to the kneaded mixture, followed by further kneading and then vulcanizing the mixture, thereby manufacturing an unvulcanized rubber composition.

[0110] Furthermore, the unvulcanized rubber composition obtained above is extruded into the shape of a tread, and is laminated together with other tire components in a tire building machine and molded in a conventional manner to form an unvulcanized tire, which can then be manufactured by heating and pressurizing it in a vulcanizer.

[0111] [Application] The tire of the present disclosure is not particularly limited to a particular category and can be used for passenger vehicle tires, heavy-duty tires for trucks, buses, etc., motorcycle tires, run-flat tires, non-pneumatic tires, etc., but due to its characteristics, it can be particularly suitably used as a tire for harsh regions and an off-road tire. [Example]

[0112] The present disclosure will be specifically described based on examples, but the present disclosure is not limited to these examples.

[0113] <Various chemicals> The various chemicals used in the examples and comparative examples will be explained below. NR:TSR20 SBR: SBR1502 manufactured by JSR Corporation (styrene content 23.5% by mass, vinyl content 16% by mass, non-oil extended) BR: UBEPOL BR150B (Mw: 440,000, high cis BR, cis-1,4 bond content: 96%) manufactured by Ube Industries, Ltd. Carbon black: N134 (N2SA:143m) manufactured by Tokai Carbon Co., Ltd. 2 / g) Silica 1: Ultrasil 9100GR (N2SA: 212m) manufactured by Evonik Degussa 2 / g) Silica 2: Ultrasil VN3 (N2SA: 175 ml) manufactured by Evonik Degussa 2 / g, average primary particle diameter: 15nm) Silane coupling agent 1: Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) manufactured by Evonik Degussa Silane coupling agent 2: NXT-Z45 (a copolymer of bonding unit A and bonding unit B (bonding unit A: 55 mol %, bonding unit B: 45 mol %)) manufactured by Momentive Wax: Ozoace 355 manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: Nocrac 6C (N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine, 6PPD) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Antioxidant 2: Nocrac RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: NOF Corporation's "Tsubaki" stearic acid beads Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Hybrid crosslinker: Vulcuren VP KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane) manufactured by Lanxess Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela NS (N-tert-butyl-2-benzothiazolyl sulfenamide (TBBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccelaer D (N,N'-diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0114] Examples and Comparative Examples According to the formulation shown in Table 1, the chemicals other than sulfur and the vulcanization accelerator were kneaded for 5 minutes using a 1.7 L internal Banbury mixer until the discharge temperature reached 170°C, yielding a kneaded mixture. The resulting kneaded mixture was then re-kneaded (remilled) for 4 minutes using the same Banbury mixer at a discharge temperature of 150°C. Next, sulfur and the vulcanization accelerator were added to the resulting kneaded mixture using a two-screw open roll mill, and the mixture was kneaded for 4 minutes until the temperature reached 105°C, yielding an unvulcanized rubber composition. The resulting unvulcanized rubber composition was press-vulcanized at 170°C for 12 minutes to produce a vulcanized rubber composition for testing.

[0115] In addition, the unvulcanized rubber composition was extruded into the shape of a tire tread using an extruder equipped with a die of a predetermined shape according to the pattern shown in Table 1, and the extruded rubber composition was laminated together with other tire components to form an unvulcanized tire, which was then press-vulcanized to produce a test tire (265 / 50R20). The shape of the circumferential main groove was zigzag in all cases.

[0116] The test vulcanized rubber compositions and test tires obtained were evaluated as follows. The evaluation results are shown in Table 1.

[0117] <Viscoelasticity test> The vulcanized rubber composition for testing was measured for tanδ (tanδ) using a viscoelasticity spectrometer VES manufactured by Iwamoto Seisakusho Co., Ltd. under the conditions of a temperature of 30°C, an initial strain of 10%, a dynamic strain of 2%, and a frequency of 10 Hz. 30℃ ) was measured.

[0118] <Tensile properties> Using No. 3 dumbbell-shaped test pieces made of the vulcanized rubber composition for testing, tensile tests were carried out at temperatures of 23°C and 80°C in accordance with JIS K 6251 "Vulcanized rubber and thermoplastic rubber - Determination of tensile properties." The elongation at break EB at 23°C was measured. 23℃(%) and elongation at break EB at 80°C 80℃ (%) was measured.

[0119] <Wear resistance index> Using an LAT tester (Laboratery Abration and Skid Tester, a rubber abrasion tester "LAT100" manufactured by Hiraizumi Yoko Co., Ltd.), the volume loss of each vulcanized rubber sheet (rubber composition after vulcanization) was measured under conditions of a load of 40 N, a speed of 20 km / h, and a slip angle of 6°. The volume loss of the rubber compound of Comparative Example 1 was set to 100, and the abrasion resistance performance index of each compound was calculated using the following calculation formula. A larger value indicates better abrasion resistance performance. (Abrasion resistance index) = (Volume loss amount of the compounding of Comparative Example 1) / (Volume loss amount of each compounding) × 100

[0120] <Off-road performance> Each test tire was mounted on all wheels of a 3600cc four-wheel drive vehicle under the following conditions. A test driver then drove the four-wheel drive vehicle on an off-road test course with a soft muddy surface and a rocky road surface. The test driver sensorily evaluated the driving characteristics, such as traction, ability to grip mud and rocks, and driving stability. The results were expressed as a score, with Comparative Example 1 being 100. The higher the score, the better the performance. Rim: 20 x 8.5J Internal pressure: 255kPa Load: 54% of normal load

[0121] [Table 1]

[0122] From the results in Table 1, the tires of the examples are superior in off-road running performance to the tires of the comparative examples, and also have a low tan δ 30℃ It can be seen that the abrasion resistance index (A), which is an index of abrasion resistance performance, and the abrasion resistance index (C) also maintain excellent values. [Industrial Applicability]

[0123] According to the present disclosure, it is possible to provide a tire that exhibits excellent off-road driving performance while also achieving low fuel consumption and wear resistance.

Claims

1. A tire having a tread made of a rubber composition including a rubber component containing 0 to 50% by mass of an isoprene-based rubber, The rubber composition satisfies the following conditions (1) to (3), (1) Tan δ (tan δ) at 30°C measured under conditions of an initial strain of 10%, a dynamic strain of 2%, and a frequency of 10 Hz 30℃ ) is A, A≧0.18 (2) Elongation at break (EB) 23℃ ) at 80°C (EB 80℃ ) ratio (EB 80℃ / EB 23℃ ) is B, 0.60≦B≦1.00 (3) When the abrasion resistance index measured by an LAT tester under conditions of a load of 40 N, a speed of 20 km / h, and a slip angle of 6° is C, with the tire of Comparative Example 1 being 100, 110≦C≦140 The tread has a crown portion having a center on the tire equator and a width that is one-third of the tread contact surface width, and a pair of shoulder portions located on both ends of the crown portion and each having a width that is one-third of the tread contact surface width, and the crown portion and the shoulder portions satisfy the following condition (4): (4) Land ratio of the crown part (LAND Cr ) for the entire pair of shoulder portions to the land ratio (LAND Sh ) ratio (LAND Sh / LAND Cr ) is D, 0.80≦D≦2.00 The tread has at least one circumferential main groove extending continuously in the tire circumferential direction, and the circumferential main groove satisfies the following condition (5): (5) When the maximum groove depth of the circumferential main groove is E (mm), 5≦E≦20 The A, B, C, D, and E satisfy the following formula (6): (6) 25≦(B×C / A)×(D / E)≦200 tire.

2. 2. The tire of claim 1, wherein the isoprene-based rubber is natural rubber.

3. The tire according to claim 1 or 2, wherein the rubber composition contains 20 to 70 parts by mass of silica per 100 parts by mass of the rubber component.

4. The nitrogen adsorption specific surface area of ​​the silica is 200 m 2 4. The tire of claim 3, wherein the tensile strength is 1 / g or more.

5. The tire according to any one of claims 1 to 4, wherein the rubber composition comprises 10 to 30 parts by mass of carbon black per 100 parts by mass of the rubber component.

6. The carbon black has a nitrogen adsorption specific surface area of ​​120 to 200 m 2 6. The tire of claim 5, wherein the tensile strength is 1 / g.

7. The tire according to any one of claims 3 to 6, wherein the rubber composition contains 2 to 20 parts by mass of a silane coupling agent per 100 parts by mass of silica.

8. The tire according to any one of claims 1 to 7, wherein the rubber composition comprises 0.5 to 4.0 parts by mass of a hybrid crosslinking agent per 100 parts by mass of the rubber component.

9. The tire according to any one of claims 1 to 8, wherein D is in the range of 0.90<D<1.

08.

10. The LAND Sh The tire according to any one of claims 1 to 9, wherein the tensile strength is 60 to 80.

11. The land ratio of the shoulder portion on the side where the convex mark is provided on the outer surface of the sidewall is defined as stencil LAN. Sh The land ratio of the shoulder part on the opposite side is set to non-stencil LAND Sh When this is done, Stencil LAND Sh <Non-stencil LAND Sh The tire according to any one of claims 1 to 10,

12. The tire according to any one of claims 1 to 11, wherein the circumferential main groove has a zigzag or wavy shape having an amplitude in the tire width direction.

13. The tire according to any one of claims 1 to 12, wherein the groove depth of the circumferential main groove is a depth corresponding to 50 to 80% of the tread thickness.

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