tire

Abstract

To provide a tire excellent in wet grip performance.SOLUTION: A tire with 60% or more of land ratio includes a tread comprising: a rubber constituent; a silica; and a compound represented by the following expression (I). [formula 1] (R1 is a hydrocarbon group in the expression (I). R2 and R3 are the same or different, which represent a hydrogen atom, a hydrocarbon group, or -(AO)n-H group (n is an integer of one or greater, and n of R2 and n of R3 are the same or different. AO is the same or different, which represents an oxyalkylene group whose carbon number is 2 or more). At least one of R2 and R3 is -(AO)n-H group.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In recent years, from the viewpoint of safety and the like, it has been desired to improve the grip performance of automobile tires, and particularly to improve the wet grip performance.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to solve the above problems and provide a tire having excellent wet grip performance.

Means for Solving the Problems

[0004] The present invention relates to a tire provided with a tread, wherein the tread contains a rubber component, silica, and a compound represented by the following formula (I), and the land ratio is 60% or more.

Chemical Formula

Effects of the Invention

[0005] According to the present invention, a tire having a tread, wherein the tread contains a rubber component, silica, and a compound represented by the above formula (I), and the land ratio is 60% or more, thereby improving wet grip performance. [Modes for carrying out the invention]

[0006] The present invention relates to a tire having a tread, wherein the tread contains a rubber component, silica, and a compound represented by formula (I), and the land ratio is 60% or more.

[0007] The reason why the aforementioned effects can be obtained with the above tires is presumed to be as follows. The compound represented by formula (I) has a structure in which a hydrocarbon (alkyl) group is attached to a hydrophilic amine. As a result, the hydrocarbon group of the compound represented by formula (I) is highly compatible with the rubber component and physically intertwines well, making it less likely to leak out of the tread. Furthermore, it is believed that the compound represented by formula (I) can uniformly disperse silica and the compound in the rubber composition by forming hydrogen bonds with the hydrophilic groups of silica and making the silica hydrophobic. Furthermore, since silica and the compound represented by formula (I) have hydrophilic portions, it is thought that when the tread comes into contact with a wet road surface, the hydrophilic portions generate adhesive force, thereby improving grip. In addition, the tire of the present invention has a structure with a large land ratio, which increases the contact area. As a result, the hydrophilic portion of the uniformly dispersed silica and compound represented by formula (I) comes into good contact with the wet road surface. Consequently, the contact area between the hydrophilic portion and the wet road surface increases, which is thought to improve wet grip performance. Based on the above effects, it is presumed that the tire of the present invention has improved wet grip performance synergistically through the combination of the compound represented by formula (I) and the tire structure.

[0008] Thus, the tire solves the problem (objective) of improving wet grip performance by having a tread composed of rubber components, silica, and a compound represented by formula (I), and having a land ratio of 60% or more. In other words, the parameter "land ratio of 60% or more" does not define the problem (objective); the problem of this application is to improve wet grip performance, and the configuration that satisfies this parameter is a means of solving that problem.

[0009] In the aforementioned tire, the tread land ratio is 60% or more, preferably 63% or more, more preferably 65% ​​or more, even more preferably 68% or more, even more preferably 70% or more, and particularly preferably 71% or more. The upper limit of the land ratio is preferably 90% or less, more preferably 85% or less, even more preferably 82% or less, and particularly preferably 80% or less. When the ratio is within the above range, a better effect tends to be obtained.

[0010] In this specification, if the tire is a pneumatic tire, the land ratio is calculated from the contact patch shape under normal rim, normal internal pressure, and normal load conditions. In the case of a non-pneumatic tire, it can be measured similarly without requiring normal internal pressure. "Official rim" refers to the rim specified for each tire within the standard system on which the tire is based. For example, it means the standard rim for JATMA, the "Design Rim" for TRA, or the "Measuring Rim" for ETRTO. "Regular internal pressure" refers to the air pressure specified for each tire by the aforementioned standards. For JATMA, it means the maximum air pressure; for TRA, it means the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it means "INFLATION PRESSURE." "Regular load" refers to the maximum load specified for each tire by the aforementioned standards. For JATMA, it means the maximum load capacity; for TRA, it means the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it means the maximum load listed under "LOAD CAPACITY". The contact patch shape is obtained by mounting the tire on a standard rim, applying the standard internal pressure, letting it stand at 25°C for 24 hours, then applying ink to the tire tread surface, applying the standard load, pressing it onto cardboard (camber angle 0°), and transferring the shape to the paper. The tire is rotated 72° in the circumferential direction, and the shape is transferred at five points. In other words, the contact patch shape is obtained five times. For the five contact patch shapes, L is the average of the maximum lengths in the tire axial direction, and W is the average of the lengths in the direction perpendicular to the axial direction. The land ratio is calculated as the average area of ​​the five contact shapes (inked areas) transferred onto the cardboard / (L × W) × 100 (%). The negative rate (%) is calculated as [1 - {average area of ​​the five contact shapes (inked areas) transferred to the cardboard / (L × W)}] × 100 (%). Here, the average values ​​of length and area are the simple average of the five values. In the formula, L × W represents the area of ​​the virtual surface obtained by connecting the gaps created by the main grooves and lateral grooves when the ground contact shape is obtained.

[0011] In the tire of the present invention, the tread is composed of a tread rubber composition comprising a rubber component, silica, and a compound represented by formula (I).

[0012] The aforementioned rubber composition contains rubber components. In the aforementioned rubber composition, the rubber component is a component that contributes to crosslinking, and is generally a polymer with a weight-average molecular weight (Mw) of 10,000 or more.

[0013] The weight-average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and also preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within this range, a better effect tends to be obtained.

[0014] In this specification, the weight-average molecular weight (Mw) can be determined by converting the measured values ​​obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation) to standard polystyrene equivalents.

[0015] The rubber component is not particularly limited, and any known component in the tire field can be used. Examples include diene rubbers such as isoprene rubber, butadiene rubber (BR), styrene-subbutadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). These may be used individually or in combination of two or more. Among these, isoprene rubber, BR, and SBR are preferred from the viewpoint of obtaining better effects, the inclusion of BR is more preferred, and the inclusion of BR and SBR is even more preferred.

[0016] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. For NR, examples include SIR20, RSS#3, TSR20, etc., which are commonly used in the tire industry. For IR, there are no particular limitations; examples include IR2200, etc., which are commonly used in the tire industry. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used individually or in combination of two or more. Among these, NR is preferred.

[0017] When the rubber composition contains isoprene-based rubber, the isoprene-based rubber content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 35% by mass or more, and also preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less. Within the above range, better effects tend to be obtained.

[0018] The type of BR used is not particularly limited. For example, high-cis content BRs such as BR1220 from Nippon Zeon Co., Ltd., BR150B from Ube Industries, Ltd., and BR1280 from LG Chem, BRs containing 1,2-syndiotactic polybutadiene crystals (SPBs) such as VCR412 and VCR617 from Ube Industries, Ltd., and butadiene rubber synthesized using rare earth element catalysts (rare earth BRs) can be used. These can be used individually or in combination of two or more types.

[0019] The cis content of BR is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and also preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less. When it is within the above range, the effect tends to be better obtained. The cis amount of BR can be measured by infrared absorption spectroscopy.

[0020] When the rubber composition contains BR, the BR content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more, and also preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0021] SBR is not particularly limited; for example, emulsion polymerized styrene-butadiene rubber (E-SBR) and solution polymerized styrene-butadiene rubber (S-SBR) can be used. Commercially available products include those from Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation.

[0022] The styrene content of SBR is preferably 10% by mass or more, more preferably 23.5% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, particularly preferably 35% by mass or more, and most preferably 36% by mass or more. The styrene content is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the content is within the above range, the effect tends to be better obtained. In this specification, the styrene content of SBR is as follows: 1 It is calculated by 1H-NMR measurement.

[0023] It is thought that using SBR with a high styrene content (for example, SBR with a styrene content of 25% by mass or more) makes it more difficult for the compound represented by formula (I) to escape from the tread, and this is presumed to have significantly improved wet grip performance.

[0024] The vinyl content of SBR is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 23% by mass or more, and particularly preferably 30% by mass or more. The vinyl content is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the content is within the above range, the effect tends to be better obtained. In this specification, the vinyl content (amount of 1,2-bonded butadiene units) of SBR can be measured by infrared absorption spectroscopy.

[0025] When the rubber composition contains SBR, the SBR content in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 45% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more, and may also be 100% by mass. Furthermore, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0026] When the rubber composition contains SBR and / or BR, the total content of SBR and BR in 100% by mass of the rubber component is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and particularly preferably 90% by mass or more, and may also be 100% by mass. Within the above range, a better effect tends to be obtained.

[0027] When a large amount of SBR and BR is present (for example, when the total content of SBR and BR is 70% by mass or more), a large amount of styrene and vinyl units that readily intertwine with hydrocarbon groups will be present, which is thought to make it more difficult for the compound represented by formula (I) to escape from the tread. Therefore, it is presumed that the wet grip performance is significantly improved.

[0028] The rubber component may be oil-stretched rubber or resin-stretched rubber. These may be used individually or in combination of two or more. Among these, oil-stretched rubber is preferred. The oil used in oil-extracted rubber and the resin used in resin-extracted rubber are the same as those described later in the section on plasticizers. Furthermore, while the oil content in oil-extracted rubber and the resin content in resin-extracted rubber are not particularly limited, they are typically around 10 to 50 parts by mass per 100 parts by mass of rubber solids.

[0029] The rubber component may have functional groups that interact with fillers such as silica introduced through modification. Examples of the above functional groups include silicon-containing groups (-SiR3 (where R is the same or different and can be hydrogen, a hydroxyl group, a hydrocarbon group, an alkoxy group, etc.), amino groups, amide groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, thiocarbonyl groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, etc. These functional groups may have substituents. Among these, silicon-containing groups are preferred, and -SiR3 (where R is the same or different and can be hydrogen, a hydroxyl group, a hydrocarbon group (preferably a hydrocarbon group having 1 to 6 carbon atoms (more preferably an alkyl group having 1 to 6 carbon atoms)) or an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms)), with at least one of R being a hydroxyl group) is more preferred.

[0030] Specific examples of compounds (modifiers) that introduce the above functional groups include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane.

[0031] The rubber composition contains silica as a filler. Examples of silica include dry-process silica (anhydrous silicic acid) and wet-process silica (hydrated silicic acid), but wet-process silica is preferred because it contains a large number of silanol groups. The raw material for silica may be water glass (sodium silicate) or biomass material such as rice husks. Commercially available products include those from Evonik Degussa, Tosoh Silica Co., Ltd., Solvay Japan Ltd., and Tokuyama Corporation. These may be used individually or in combination of two or more types.

[0032] The nitrogen adsorption specific surface area (N2SA) of silica is preferably 120 m². 2 / g or more, comfortable 150m 2 / g or more, more preferably 160m 2 The amount is 1 / g or more. The N2SA is preferably 200m 2 Less than / g, more preferably 195m 2 / g or less, more preferably 185m 2 It is less than / g. Also, the lower or upper limit of N2SA for the silica is 175m 2 / g is also acceptable. In this specification, the N2SA of silica is the value measured by the BET method in accordance with ASTM D3037-81.

[0033] In the rubber composition, the silica content is preferably 30 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, particularly preferably 65 parts by mass or more, most preferably 90 parts by mass or more, per 100 parts by mass of the rubber component, and also preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 parts by mass or less. When the silica content is within the above range, the effect tends to be better obtained.

[0034] When the silica content is increased (for example, to 60 parts by mass or more), the hydrophilic portion of the silica in the rubber increases, which is thought to increase the adhesion force to the road surface. Therefore, it is presumed that the wet grip performance is significantly improved.

[0035] Other fillers that can be used besides silica include, for example, inorganic fillers other than silica and carbon black. Examples of inorganic fillers other than silica include clay, alumina, talc, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium oxide, and titanium oxide. These may be used individually or in combination of two or more. Among these, carbon black is preferred.

[0036] The carbon black used is not particularly limited and includes N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw material for the carbon black may be biomass material such as lignin or vegetable oil. The manufacturing method for the carbon black may be combustion, such as the furnace process, or hydrothermal carbonization (HTC). Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Corporation. These may be used individually or in combination of two or more types.

[0037] The nitrogen adsorption specific surface area (N2SA) of carbon black is 100m². 2 Preferably 120m / g or more. 2More preferably 140m / g or more. 2 More preferably 142m / g or more. 2 A value of 1 / g or more is particularly preferred. Furthermore, the above N2SA is 200m 2 Preferably less than / g, 180m 2 More preferably less than / g, 160m 2 A value of less than / g is even more preferable. Within the above range, there is a tendency to obtain better effects. The specific surface area for nitrogen adsorption of carbon black is determined according to JIS K6217-2:2001.

[0038] In the rubber composition, the carbon black content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more, per 100 parts by mass of the rubber component. It is also preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0039] When the carbon black content is increased (for example, 10 parts by mass or more), it is thought that adding a compound represented by formula (I), which is highly compatible with hydrocarbon groups, can make it more difficult for the compound to escape. Therefore, it is presumed that the wet grip performance has been significantly improved.

[0040] In the aforementioned rubber composition, the filler content (total content of silica, carbon black, etc.) is preferably 30 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, particularly preferably 90 parts by mass or more, and most preferably 95 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, it is preferably 150 parts by mass or less, more preferably 130 parts by mass or less, even more preferably 115 parts by mass or less, and particularly preferably 105 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0041] The rubber composition contains a compound represented by the following formula (I). The compound represented by formula (I) may be used alone or in combination of two or more types. [ka] (In formula (I), R 1 R represents a hydrocarbon group. 2 , R 3 These are the same or different hydrogen atoms (-H), hydrocarbon groups, or -(AO) n -H base (where n is an integer greater than or equal to 1, R 2 , R 3 Each n may be the same or different. AO represents an oxyalkylene group having 2 or more carbon atoms, either the same or different. ) represents R 2 , R 3 At least one of them is -(AO) n -It is an H group.

[0042] R 1 ~R 3 The hydrocarbon group may be linear, branched, or cyclic, and examples include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. Among these, aliphatic hydrocarbon groups are preferred. The number of carbon atoms in the hydrocarbon group is preferably 1 or more, more preferably 5 or more, even more preferably 8 or more, particularly preferably 12 or more, preferably 30 or less, more preferably 25 or less, even more preferably 22 or less, and particularly preferably 20 or less. Within the above range, the effect tends to be more favorably obtained.

[0043] Examples of aliphatic hydrocarbon groups include alkyl groups, alkylene groups, alkenyl groups, alkenylene groups, alkynyl groups, and alkynylene groups. Among these, alkyl groups with the above number of carbon atoms are preferred. Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, and octadecyl group.

[0044] Preferred alicyclic hydrocarbon groups have 3 to 8 carbon atoms, and specifically include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, and cyclooctenyl group.

[0045] Preferred aromatic hydrocarbon groups have 6 to 10 carbon atoms, specifically including phenyl, benzyl, phenethyl, tolyl, xylyl, and naphthyl groups. The substitution position of the methyl group on the benzene ring in the tolyl and xylyl groups may be at the ortho, meta, or para position.

[0046] R 2 , R 3 no-(AO) n -H base (where n is an integer greater than or equal to 1, R 2 , R 3 Each n in ( ) may be the same or different. AO in ( ) may be the same or different and represent an oxyalkylene group having 2 or more carbon atoms. The number of carbon atoms is preferably 3 or more, and although there is no particular upper limit, it is preferably 7 or less, more preferably 6 or less, and even more preferably 5 or less. Within the above range, the effect tends to be more favorably obtained.

[0047] The alkylene group A in the oxyalkylene group AO may be linear or branched. For the reason that the effect is more favorably obtained, AO is branched into an oxyalkylene group (oxyethylene group (EO), oxypropylene group (PO)) with 2 to 3 carbon atoms. 4 (R 4 represents a hydrocarbon group. Preferably, it is a group to which ) is bonded, -(AO) n -H group is more preferably a group represented by the following formulas (A) and (B), and even more preferably a group represented by the following formula (A). Also, branched chain R 4It is preferable that it is bonded to a carbon atom adjacent to the oxygen atom. [ka] (In formulas (A) and (B), R 4 represents a hydrocarbon group. n is -(AO) n - This is similar to the n of the H group.

[0048] R 4 The hydrocarbon group is R 1 ~R 3 Examples of groups similar to hydrocarbon groups include aliphatic hydrocarbon groups, and alkyl groups are more preferred. The number of carbon atoms in the hydrocarbon group (preferably an aliphatic hydrocarbon group, more preferably an alkyl group) is preferably 1 or more, more preferably 2 or more, preferably 6 or less, more preferably 5 or less, even more preferably 4 or less, and particularly preferably 3 or less. Within the above range, the effect tends to be more favorably obtained.

[0049] (AO) n If the compound contains two or more oxyalkylene groups, the sequence of the oxyalkylene groups may be in a block or random order.

[0050] n represents the number of moles of AO added. n is preferably 1 or more, more preferably 2 or more, preferably 20 or less, more preferably 16 or less, even more preferably 10 or less, particularly preferably 5 or less, and most preferably 3 or less. When n is within the above range, the effect tends to be more favorably obtained.

[0051] In equation (I), R 2 , R 3 At least one of them is -(AO) n -H group, R 2 , R 3 All of the above - (AO) n -It is more preferable that the group is an H group. That is, the compound represented by formula (I) above is even more preferably the compound represented by formula (I-1) below. This tends to result in a more favorable effect. [ka] (Equation (I-1) is the same as equation (I), except that n1 and n2 represent integers greater than or equal to 1 (integers similar to n).)

[0052] In formulas (I) and (I-1), the total number of moles of AO added (n1 + n2) is preferably 2 or more, more preferably 3 or more, even more preferably 4 or more, preferably 40 or less, more preferably 32 or less, even more preferably 20 or less, particularly preferably 10 or less, and most preferably 6 or less. Within the above range, the effect tends to be more favorably obtained.

[0053] Specific examples of compounds represented by formula (I) include, for example, liponols manufactured by Lion Specialty Chemicals Co., Ltd. (in formula (I), R 2 :-(CH2CH2)xH, R 3 Examples include :-(CH2CH2)yH). These can be used individually or in combination of two or more.

[0054] Specific examples of compounds represented by the above formula (I-1) include, for example, POE(2)octylamine, POE(4)decylamine, POE(2)dodecylamine, POE(5)dodecylamine, POE(15)dodecylamine, POE(2)tetradecylamine, POE(2)hexadecylamine, POE(2)octadecylamine, POE(20)octadecylamine, and POE(2)octadecenylamine. Note that POE(m) indicates that an average of m moles of polyoxyethylene are added. Commercially available products such as Amito 102 (POE(2)dodecylamine), Amito 105 (POE(5)dodecylamine), Amito 302 (POE(2)octadecylamine), and Amito 320 (POE(20)octadecylamine) manufactured by Kao Corporation can be used.

[0055] The compound represented by formula (I) may be the commercially available product mentioned above, or it may be a compound manufactured separately from these commercially available products. Possible manufacturing methods include, for example, reacting a polyhydric amine compound with an alkylene oxide, either in the presence of a catalyst or without a catalyst, but the method is not limited to this.

[0056] In the rubber composition, the content of the compound represented by formula (I) (total content when two or more are used in combination) is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, particularly preferably 4.0 parts by mass or more, and most preferably 5.0 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, the content is preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 6.0 parts by mass or less, per 100 parts by mass of the rubber component. When the compound content is within the above range, the effect is more favorably obtained.

[0057] From the viewpoint of obtaining better results, it is desirable that the rubber composition contains a silane coupling agent. The silane coupling agent is not particularly limited and includes, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl) trisulfide, bis(4-trimethoxysilylbutyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl Examples include sulfide-based compounds such as ropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those from companies such as Evonik Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. These can be used individually or in combination of two or more. Among these, sulfide-based silane coupling agents, mercapto-based silane coupling agents, and amino-based silane coupling agents are preferred from the viewpoint of obtaining good handling stability and low fuel consumption performance.

[0058] In the rubber composition, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of silica, and also preferably 16 parts by mass or less, more preferably 14 parts by mass or less, and even more preferably 12 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0059] From the viewpoint of obtaining better effects, it is desirable that the rubber composition contains a resin as a plasticizer. While known resins can be used, it is preferable to use at least one resin selected from the group consisting of C5 resins, C5 / C9 resins, C9 resins, coumarone indene resins, styrene resins, terpene resins, cyclopentadiene resins, and their hydrogenated derivatives.

[0060] C5 resins are polymers that contain a C5 fraction as a constituent monomer. Examples include polymers obtained by polymerizing a C5 fraction, which is obtained by the thermal decomposition of naphtha in the petrochemical industry, using a Friedel-Crafts type catalyst such as AlCl3 or BF3. The C5 fraction typically includes olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene; and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene.

[0061] C5 / C9 resins are polymers containing C5 and C9 fractions as constituent monomers. Examples include polymers obtained by polymerizing petroleum-derived C5 and C9 fractions using Friedel-Crafts type catalysts such as AlCl3 and BF3. Specifically, examples include copolymers mainly composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. In this specification, C5 / C9 resins are treated as separate resins from styrene resins, C5 resins, and C9 resins.

[0062] C9 resins are polymers that contain a C9 fraction as a constituent monomer. For example, they can be obtained by polymerizing the C9 fraction, which is produced as a by-product along with basic petrochemical raw materials such as ethylene and propylene during the thermal decomposition of naphtha in the petrochemical industry, using a Friedel-Crafts type catalyst such as AlCl3 or BF3. Specific examples of C9 fractions include vinyltoluene, α-methylstyrene, β-methylstyrene, γ-methylstyrene, o-methylstyrene, p-methylstyrene, and indene. C9 resins may also be obtained by copolymerizing a mixture of these C8-C10 fractions, for example, using a Friedel-Crafts type catalyst, along with the C9 fraction, including C8 fractions such as styrene, C10 fractions such as methylindene and 1,3-dimethylstyrene, and even naphthalene, vinylnaphthalene, vinylanthracene, and p-tert-butylstyrene. In this specification, C9 resins are treated as a separate resin from styrene resins.

[0063] Coumaron-indene resins are polymers containing coumaron and indene as constituent monomers. Examples include copolymers of coumaron and indene, as well as copolymers of coumaron and indene with other monomers that can copolymerize with them.

[0064] Styrene resins are polymers that contain styrene monomers as constituent monomers. Examples include homopolymers obtained by polymerizing one type of styrene monomer alone, copolymers obtained by copolymerizing two or more types of styrene monomers, and copolymers of styrene monomers and other monomers that can copolymerize with it.

[0065] Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene. These may be used individually or in combination of two or more. Among these, styrene and α-methylstyrene are more preferred.

[0066] To obtain better results, the styrene-based resin is preferably an α-methylstyrene-based resin (α-methylstyrene homopolymer, copolymer of styrene and α-methylstyrene, etc.), and more preferably a styrene-α-methylstyrene resin (polymer of styrene and α-methylstyrene)).

[0067] Terpene resins are polymers that contain terpene compounds (terpene monomers) as constituent monomers. Examples include homopolymers obtained by polymerizing one type of terpene compound alone, copolymers obtained by copolymerizing two or more types of terpene compounds, and copolymers of a terpene compound and other monomers that can copolymerize it.

[0068] Terpene compounds are (C5H8) n A hydrocarbon and its oxygen-containing derivative represented by the following composition, monoterpene (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpene (C 20 H 32 These are compounds with a terpene as their basic skeleton, classified as such, and examples include α-pinene, β-pinene, dipentene, limonene, myrcene, allocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc. These may be used individually or in combination of two or more.

[0069] To obtain better effects, the terpene resin is preferably a homopolymer of a terpene compound (polyterpene resin), a copolymer of a terpene compound and a styrene monomer, and more preferably a copolymer of a terpene compound and a styrene monomer. Furthermore, the copolymer of a terpene compound and a styrene monomer is preferably a copolymer of a terpene compound and styrene (terpene styrene resin). In this specification, polymers containing terpene compounds and styrene monomers as constituent monomers, such as terpene styrene resins, are treated as terpene resins, not styrene resins.

[0070] Cyclopentadiene resins are polymers that contain cyclopentadiene monomers as constituent monomers. Examples include homopolymers obtained by polymerizing one type of cyclopentadiene monomer alone, copolymers obtained by copolymerizing two or more types of cyclopentadiene monomers, and copolymers of cyclopentadiene monomers with other monomers that can copolymerize with it.

[0071] Examples of cyclopentadiene monomers include cyclopentadiene, dicyclopentadiene, and tricyclopentadiene. These may be used individually or in combination of two or more. Dicyclopentadiene is particularly preferred. Specifically, the cyclopentadiene resin is preferably a polymer (DCPD resin) containing dicyclopentadiene (DCPD) as a constituent monomer, and a hydrogenated DCPD resin is more preferred.

[0072] From the viewpoint of obtaining better effects, the resin preferably contains a styrene-based resin and a terpene-based resin.

[0073] It is believed that using resins, particularly styrene-based and terpene-based resins, increases the compound's Tg and thus its tanδ (energy loss). Therefore, it is presumed that the wet grip performance has improved.

[0074] In the aforementioned rubber composition, the resin content (total amount) is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0075] In the rubber composition, the styrene resin content is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0076] In the rubber composition, the content of the terpene resin is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0077] The resin described above may be a solid resin that is solid at room temperature (25°C), or a liquid resin that is liquid at room temperature (25°C). To obtain a better effect, it is preferable that the resin contains at least a solid resin.

[0078] The softening point of the above resin is preferably 50°C or higher, more preferably 80°C or higher, even more preferably 85°C or higher, and even more preferably 90°C or higher, and also preferably 180°C or lower, more preferably 130°C or lower, and even more preferably 125°C or lower. In this disclosure, the softening point of the resin is defined as the temperature at which the sphere descends when the softening point specified in JIS K 6220-1:2001 is measured using a ring-type softening point measuring device.

[0079] In the aforementioned rubber composition, the solid resin content is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0080] In the aforementioned rubber composition, the liquid resin content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the rubber component, and may be 0 parts by mass. When the content is within the above range, a better effect tends to be obtained.

[0081] Commercially available resins from companies such as Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0082] As plasticizers other than resins, for example, liquid polymers, oils (including the oil content in oil-applied rubber), etc., can be used. These may be used individually or in combination of two or more. Among these, oil is preferred.

[0083] Examples of oils include process oils, vegetable oils, or mixtures thereof. Examples of process oils include paraffinic process oils, aromatic process oils, naphthenic process oils, etc. 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 oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil, etc. In addition to these, from the perspective of life cycle assessment, oils that have been used as lubricants for rubber processing mixers and engines, or oils obtained by refining waste cooking oil used in restaurants, may also be used as appropriate. Commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., and Fuji Kosan Co., Ltd. may be used. These may be used individually or in combination of two or more types.

[0084] In the rubber composition, the oil content is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, even more preferably 37.5 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0085] In the rubber composition, the content of plasticizer (total content of resin, oil, etc.) is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 47.5 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 55 parts by mass or more, per 100 parts by mass of the rubber component. Also, preferably 100 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and particularly preferably 70 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0086] The aforementioned rubber composition may contain an anti-aging agent. Examples of anti-aging agents include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4′-bis(α,α′-dimethylbenzyl)diphenylamine; N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, and N,N′-di-2-naphthyl-p-phenylenediamine. Examples include p-phenylenediamine-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers and other quinoline-based antioxidants; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane. Commercially available products include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd. These may be used individually or in combination of two or more.

[0087] In the aforementioned rubber composition, the content of the anti-aging agent is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, even more preferably 1.0 part by mass or more, and also preferably 10.0 parts by mass or less, more preferably 6.0 parts by mass or less, even more preferably 4.0 parts by mass or less, and particularly preferably 3.5 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0088] The rubber composition may contain wax. The wax is not particularly limited and can be any petroleum-based wax such as paraffin wax or microcrystalline wax; a natural wax such as plant-based wax or animal-based wax; or a synthetic wax such as polymers of ethylene or propylene. Commercially available products from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd. can be used. These can be used individually or in combination of two or more types.

[0089] In the aforementioned rubber composition, the wax content is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0090] The rubber composition may contain stearic acid. Conventional known stearic acid can be used, and commercially available products from companies such as NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries Ltd., and Chiba Fatty Acid Co., Ltd. can be used. These may be used individually or in combination of two or more types.

[0091] In the rubber composition, the stearic acid content is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 1.5 parts by mass or more, and preferably 10.0 parts by mass or less, and more preferably 6.0 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0092] The rubber composition may contain zinc oxide. Conventional known zinc oxides can be used, and commercially available products from companies such as Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd. can be used. These may be used individually or in combination of two or more types.

[0093] In the aforementioned rubber composition, the zinc oxide content is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 1.5 parts by mass or more, and preferably 10.0 parts by mass or less, and more preferably 6.0 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0094] The aforementioned rubber composition may contain sulfur. Examples of sulfur commonly used as a crosslinking agent in the rubber industry include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur. Commercially available products from companies such as Tsurumi Chemical Industries, Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industry Co., Ltd. can be used. These may be used individually or in combination of two or more types.

[0095] In the aforementioned rubber composition, the sulfur content is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 1.5 parts by mass or more, and also preferably 3.5 parts by mass or less, more preferably 2.8 parts by mass or less, and even more preferably 2.5 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0096] The rubber composition may contain a vulcanization accelerator. Examples of vulcanization accelerators include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD) and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiadylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide, and N,N′-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, dioltotolylguanidine, and orthotolylbiguanidine. Commercially available products include those from Sumitomo Chemical Co., Ltd. and Ouchi Shinko Chemical Co., Ltd. These may be used individually or in combination of two or more.

[0097] In the rubber composition, the content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 4 parts by mass or more, and also preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0098] In addition to the above components, the rubber composition may further contain additives commonly used in the tire industry, such as organic peroxides. The content of these additives is preferably 0.1 to 200 parts by mass per 100 parts by mass of the rubber component.

[0099] The rubber composition can be produced, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or Banbury mixer, and then vulcanizing them.

[0100] Regarding the mixing conditions, in the base mixing step where additives other than the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 100 to 180°C, preferably 120 to 170°C. In the finish mixing step where the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is usually 120°C or lower, preferably 80 to 110°C (more preferably 85 to 110°C). Furthermore, the composition mixed with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190°C, preferably 150 to 185°C. The vulcanization time is usually 5 to 15 minutes.

[0101] From the viewpoint of obtaining a better effect, it is desirable that the rubber composition contains the resin, and that the content of the resin (parts by mass) per 100 parts by mass of the rubber component and the content of the silica (parts by mass) per 100 parts by mass of the rubber component satisfy the following formula. Resin content × Silica content ≥ 500 The lower limit of the resin content × silica content is preferably 550 or more, more preferably 650 or more, even more preferably 800 or more, and particularly preferably 900 or more. The upper limit is preferably 1500 or less, more preferably 1300 or less, even more preferably 1200 or less, and particularly preferably 1100 or less. Within the above range, a better effect tends to be obtained.

[0102] When the resin content multiplied by the silica content is high (for example, exceeding 650), the product of the amount of silica with hydrophilic groups and the amount of resin exceeds a predetermined level. This is thought to make it easier to obtain a synergistic effect from the improved wet grip performance due to increased silica adhesion to the road surface and the improved wet grip performance due to the resin formulation. Therefore, it is presumed that the wet grip performance has been significantly improved.

[0103] From the viewpoint of obtaining a better effect, it is desirable that the rubber composition contains the resin, and that the content of the resin (parts by mass) per 100 parts by mass of the rubber component and the content of the compound represented by formula (I) (parts by mass) per 100 parts by mass of the rubber component satisfy the following formula. Resin content × Compound content represented by formula (I) ≥ 10.0 The lower limit of the resin content × the content of the compound represented by formula (I) is preferably 15.0 or more, more preferably 15.5 or more, even more preferably 18.0 or more, even more preferably 20.0 or more, even more preferably 30.0 or more, particularly preferably 40.0 or more, and most preferably 50.0 or more. The upper limit is preferably 100.0 or less, more preferably 80.0 or less, and even more preferably 60.0 or less. When the content is within the above range, the effect tends to be better obtained.

[0104] When the resin content multiplied by the compound content represented by formula (I) is high (for example, exceeding 15.0), the product of the amount of the hydrophilic compound and the amount of resin exceeds a predetermined value. This increases the contact area between the hydrophilic portion and the wet road surface, resulting in a synergistic effect from the improved wet grip performance due to the increased hydrophilic portion and the improved wet grip performance due to the resin formulation. Therefore, it is presumed that the wet grip performance has been significantly improved.

[0105] In the tire of the present invention, the rubber composition is used in the tread (particularly the portion that comes into contact with the road surface during driving (cap tread)).

[0106] In the tire of the present invention, from the viewpoint of obtaining a better effect, it is desirable that the silica content (parts by mass) and the land ratio (%) relative to 100 parts by mass of the rubber component satisfy the following formula. Silica content × land ratio > 3000 The silica content × land ratio is preferably 3300 or more, more preferably 3500 or more, even more preferably 3850 or more, even more preferably 3900 or more, even more preferably 4000 or more, even more preferably 4095 or more, even more preferably 4400 or more, even more preferably 4615 or more, even more preferably 5000 or more, even more preferably 5200 or more, even more preferably 5670 or more, and particularly preferably 6000 or more. There is no particular upper limit, but the silica content × land ratio is preferably 10000 or less, more preferably 8000 or less, even more preferably 7000 or less, and particularly preferably 6300 or less. When within the above range, the effect tends to be better obtained.

[0107] When the silica content multiplied by the land ratio is high (for example, exceeding 4000), the product of the amount of silica with hydrophilic groups and the contact area with the road surface exceeds a predetermined level. This is thought to make it easier to obtain a synergistic effect from increased silica adhesion to the road surface and an increased land ratio. Therefore, it is presumed that the wet grip performance has been significantly improved.

[0108] In the tire of the present invention, from the viewpoint of obtaining a better effect, it is desirable that the content (parts by mass) of the compound represented by formula (I) and the land ratio (%) in relation to 100 parts by mass of the rubber component satisfy the following formula. Content of the compound represented by formula (I) × Land ratio > 100 The content of the compound represented by formula (I) multiplied by the land ratio is preferably greater than 110, more preferably 120 or greater, even more preferably greater than 120, even more preferably 126 or greater, even more preferably greater than 130, even more preferably greater than 135, even more preferably 140 or greater, and particularly preferably 142 or greater. There is no particular upper limit, but the content of the compound represented by formula (I) multiplied by the land ratio is preferably 500 or less, more preferably 400 or less, even more preferably 360 or less, even more preferably 240 or less, even more preferably 210 or less, even more preferably 200 or less, even more preferably 180 or less, even more preferably 170 or less, and particularly preferably 160 or less. When within the above range, there is a tendency to obtain a better effect.

[0109] When the content of the compound represented by formula (I) multiplied by the land ratio is high (for example, exceeding 130), the product of the amount of the compound with hydrophilic properties and the contact area with the road surface exceeds a predetermined value. This increases the contact area between the hydrophilic properties and the wet road surface, making it easier to obtain a synergistic effect from the increase in hydrophilic properties and the increase in the land ratio. Therefore, it is presumed that the wet grip performance has been significantly improved.

[0110] The aforementioned tire may have either a single-layer tread or a multi-layer tread. The multilayer treads mentioned above include a two-layer tread consisting of a cap tread (a rubber layer placed on the outermost surface of the tread) and a base tread (a rubber layer placed adjacent to the cap tread on the radially inward side of the tire), and any multilayer tread with two or more layers.

[0111] In the case of a tire with a multi-layered tread, from the viewpoint of obtaining a more favorable effect, each rubber layer constituting the multi-layered tread may contain the compound. In particular, in the case of a two-layered tread consisting of a cap tread and a base tread, it is desirable that both the rubber layers of the cap tread and the base tread contain the compound.

[0112] In the case of the aforementioned two-layer tread structure, from the viewpoint of obtaining the effect more favorably, it is desirable that the content of the compound represented by formula (I) in the cap tread (content of the compound represented by formula (I) per 100 parts by mass of rubber component in the cap tread (parts by mass)) and the content of the compound represented by formula (I) in the base tread (content of the compound represented by formula (I) per 100 parts by mass of rubber component in the base tread (parts by mass)) satisfy the following formula. Content of the compound represented by formula (I) in the cap tread > Content of the compound represented by formula (I) in the base tread

[0113] In the case of the two-layer tread structure described above, the rubber composition for the cap tread constituting the cap tread contains a compound represented by formula (I) (total content when two or more are used in combination) preferably at a concentration of 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, particularly preferably 4.0 parts by mass or more, and most preferably 5.0 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, the content is preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 6.0 parts by mass or less, per 100 parts by mass of the rubber component. The effect is more favorably obtained when the content is within the above range.

[0114] In the case of the two-layer tread structure described above, the base tread rubber composition constituting the base tread contains, preferably, 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass or more, of the compound represented by formula (I) per 100 parts by mass of the rubber component. Furthermore, the content is preferably 10.0 parts by mass or less, more preferably 2.0 parts by mass or less, even more preferably 1.5 parts by mass or less, and particularly preferably 1.0 part by mass or less, per 100 parts by mass of the rubber component. The effect is more favorably obtained when the content is within the above range.

[0115] The tire of the present invention is manufactured by conventional methods using the above-mentioned rubber composition. Specifically, the rubber composition is extruded to match the shape of the tread at the unvulcanized stage, and then molded together with other tire components in a conventional manner on a tire molding machine to form an unvulcanized tire. This unvulcanized tire is then heated and pressurized in a vulcanizing machine to obtain a tire.

[0116] The above-mentioned tires (pneumatic tires, etc.) can be used for passenger car tires; truck and bus tires; motorcycle tires; high-performance tires; winter tires such as studless tires and tires for low-temperature roads; run-flat tires with side reinforcement layers; sound-absorbing tires with sound-absorbing materials such as sponges inside the tire cavity; sealing materials with sealant that can be sealed in the event of a puncture inside the tire or tire cavity; and electronic component tires with electronic components such as sensors and wireless tags inside the tire or tire cavity, and are particularly suitable for passenger car tires. [Examples]

[0117] The present invention will be specifically described based on the examples provided, but the present invention is not limited to these examples.

[0118] The various chemicals used in the examples and comparative examples are described below.

[0119] NR:TSR20 SBR1: Toughden 3830 manufactured by Asahi Kasei Corporation (36% styrene by mass, 23% vinyl by mass, 37.5 parts oil per 100 parts rubber solids by mass) SBR2: SBR1502 manufactured by JSR Corporation (styrene content 23.5% by mass) BR: BR360L manufactured by Ube Industries, Ltd. (98% cis-1,4 bond content) Carbon Black: Seast 9H (N2SA142m) manufactured by Tokai Carbon Co., Ltd. 2 / g) Silica: Evonik Degussa's UltraSil VN3 (N2SA175m 2 / g) Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik DeGussa. Compound 1: Liponol HT / 14 (compound represented by formula (I-1) above), manufactured by Lion Specialty Chemicals Co., Ltd. Compound 2: Liponol T / 15 (compound represented by formula (I-1) above), manufactured by Lion Specialty Chemicals Co., Ltd. Compound 3: Liponol C / 15 manufactured by Lion Specialty Chemicals Co., Ltd. (a compound represented by the above formula (I) (the above formula (I-1))) Compound 4: Amito 102 (POE(2)dodecylamine, a compound represented by the above formula (I-1)) manufactured by Kao Corporation. Resin 1: Sylvatraxx 4150 manufactured by Arizona Chemical Corporation (β-pinene resin, β-pinene content 98% by mass or more, Mw 2350, Mn 830) Resin 2: SYLVARES SA85 manufactured by Arizona Chemical Corporation (α-methylstyrene resin (polymer of α-methylstyrene and styrene), softening point 85°C) Resin 3: YS Resin TO125 (aromatic modified terpene resin, softening point 125°C) manufactured by Yasuhara Chemical Co., Ltd. Resin 4: NOVARES C90 (coumarone indene resin, softening point 90°C) manufactured by Rutgers Chemicals. Oil: Diana Process NH-70S (aroma-type process oil) manufactured by Idemitsu Kosan Co., Ltd. Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Anti-aging agent 1: Nocrack 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent 2: Nocrack FR manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: Stearic acid "Tsubaki" manufactured by NOF Corporation Wax: Ozoace0355 manufactured by Nippon Seiro Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industries Co., Ltd. Vulcanization accelerator 1: Noxellar D (N,N'-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noxellar CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0120] (Examples and Comparative Examples) According to the formulations shown in each table, all chemicals except sulfur and vulcanization accelerator were mixed at 150°C for 5 minutes using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a mixture. Next, sulfur and vulcanization accelerator were added to the mixture and kneaded at 80°C for 5 minutes using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was molded into the shape of a cap tread, bonded together with other tire components to produce an unvulcanized tire, and then press-vulcanized at 170°C for 10 minutes to obtain a test tire (passenger car tire, size: 205 / 70R15). The following evaluations were performed using the obtained test tires, and the results are shown in the respective tables.

[0121] Furthermore, the evaluation criteria used when calculating the index in the evaluation below are as follows: Tables 1 and 2: Comparative Example 10

[0122] (Wet grip performance) Test tires were mounted on a domestically produced 2000cc front-wheel-drive vehicle, and the vehicle was driven on a wet road surface. The stopping distance was measured when braking at 100 km / h without ABS. The benchmark comparison was set to 100, and the results were expressed as an index using the following formula. A higher index indicates better wet grip performance. (Wet grip performance index) = (Stopping distance of the standard comparison example) / (Stopping distance of each formulation) × 100

[0123] [Table 1]

[0124] [Table 2]

[0125] From each table, the examples showed superior wet grip performance compared to the comparative examples.

[0126] The present invention (1) is a tire having a tread, The tread is a tire that contains rubber components, silica, and a compound represented by the following formula (I), and has a land ratio of 60% or more. [ka] (In formula (I), R 1 R represents a hydrocarbon group. 2 , R 3 These are identical or different hydrogen atoms, hydrocarbon groups, or -(AO) n -H base (where n is an integer greater than or equal to 1, R 2 , R 3 Each n may be the same or different. AO represents an oxyalkylene group having 2 or more carbon atoms, either the same or different. ) represents R 2 , R 3 At least one of them is -(AO) n -It is an H group.

[0127] The present invention (2) is a tire according to the present invention (1), wherein the tread has a total content of styrene-butadiene rubber and butadiene rubber in 100% by mass of the rubber component of 70% by mass or more.

[0128] The present invention (3) is a tire according to the present invention (1) or (2), wherein the tread comprises styrene-butadiene rubber having a styrene content of 25% by mass or more.

[0129] The present invention (4) is a tire according to any one of the present inventions (1) to (3), wherein the tread contains 60 parts by mass or more of silica per 100 parts by mass of the rubber component.

[0130] The present invention (5) is a tire according to any one of the present inventions (1) to (4), wherein the tread contains 10 parts by mass or more of carbon black per 100 parts by mass of the rubber component.

[0131] The present invention (6) is a tire according to any one of the present inventions (1) to (5) wherein the tread satisfies the following formulas for the silica content (parts by mass) and the land ratio (%) relative to 100 parts by mass of the rubber component. Silica content × land ratio > 4000

[0132] The present invention (7) is a tire according to any one of the present inventions (1) to (6), wherein the tread comprises butadiene rubber.

[0133] The present invention (8) is a tire according to any one of the present inventions (1) to (7), wherein the tread comprises at least one selected from the group consisting of styrene resins and terpene resins.

[0134] The present invention (9) is a tire according to any one of the present inventions (1) to (8), wherein the tread contains a resin, and the content of the resin (parts by mass) and the content of the silica (parts by mass) per 100 parts by mass of the rubber component satisfy the following formula. Resin content × Silica content ≥ 650

[0135] The present invention (10) is a tire according to any one of the present inventions (1) to (9), wherein the tread contains a resin, and the content of the resin (parts by mass) and the content of the compound represented by formula (I) (parts by mass) relative to 100 parts by mass of the rubber component satisfy the following formula. Resin content × Compound content represented by formula (I) ≥ 15.0

[0136] The present invention (11) is a tire according to any one of the present inventions (1) to (10) wherein the tread satisfies the following formulas: the content (parts by mass) of the compound represented by formula (I) per 100 parts by mass of the rubber component and the land ratio (%). Content of the compound represented by formula (I) × Land ratio > 130

Claims

1. A tire having a tread, The tread of the tire comprises a rubber component, silica, and a compound represented by the following formula (I), and has a land ratio of 60% or more. 【Chemistry 1】 (In formula (I), R １ represents a hydrocarbon group. R ２ , R ３ are the same or different and each represents a hydrogen atom, a hydrocarbon group, or a -(AO) ｎ -H group (n represents an integer of 1 or more, and each n of R ２ , R ３ may be the same or different. AO represents the same or different oxyalkylene groups having 2 or more carbon atoms).) and at least one of R ２ , R ３ is a -(AO) ｎ -H group.)

2. The tire according to claim 1, wherein the tread has a total content of styrene-butadiene rubber and butadiene rubber in 100% by mass of the rubber component of 70% by mass or more.

3. The tire according to claim 1 or 2, wherein the tread comprises styrene-butadiene rubber having a styrene content of 25% by mass or more.

4. The tire according to claim 1 or 2, wherein the tread contains 60 parts by mass or more of silica with respect to 100 parts by mass of the rubber component.

5. The tire according to claim 1 or 2, wherein the tread contains 10 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component.

6. The tire according to claim 1 or 2, wherein the tread satisfies the following formula in terms of the silica content (parts by mass) relative to 100 parts by mass of the rubber component and the land ratio (%). Silica content × land ratio > 4000

7. The tire according to claim 1 or 2, wherein the tread comprises butadiene rubber.

8. The tire according to claim 1 or 2, wherein the tread comprises at least one selected from the group consisting of styrene resins and terpene resins.

9. The aforementioned tread contains resin, The tire according to claim 1 or 2, wherein the content of the resin (parts by mass) and the content of the silica (parts by mass) relative to 100 parts by mass of the rubber component satisfy the following formula. Resin content × Silica content ≥ 650

10. The aforementioned tread contains resin, The tire according to claim 1 or 2, wherein the content of the resin (parts by mass) and the content of the compound represented by formula (I) (parts by mass) relative to 100 parts by mass of the rubber component satisfy the following formula. Resin content × Compound content represented by formula (I) ≥ 15.0

11. The tire according to claim 1 or 2, wherein the tread has a content (parts by mass) of the compound represented by formula (I) per 100 parts by mass of the rubber component, and the land ratio (%) satisfies the following formula. Content of the compound represented by formula (I) × Land ratio > 130

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