Tire

Abstract

To provide a tire which can improve total performance of anti-wear performance, snow grip performance, and wet grip performance.SOLUTION: A tire has a tread part, wherein the tread part is composed of a rubber composition containing a rubber component, silica, a resin component, and vegetable oil, the rubber component contains 20 mass% or more and 90 mass% or less of styrene-butadiene rubber, the rubber composition contains more than 50 pts.mass and 150 pts.mass or less of silica with respect to 100 pts.mass of the rubber component, the resin component contains at least one selected from the group consisting of a terpene-based resin, a C5C9-based resin, and a dicyclopentadiene-based resin, a glass transition temperature of the rubber composition is -30°C or lower, and when a thickness of a thickest part of the tread part is represented by t (mm), and a styrene content of the styrene butadiene rubber is represented by S (mass%), t×S is less than 300.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire. [Background technology]

[0002] As a means for achieving both wear resistance and snow performance in winter tires, a method of compounding a rubber component with a low glass transition temperature into the tread rubber is known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-2868 Summary of the Invention [Problem to be solved by the invention]

[0004] When a rubber component with a low glass transition temperature is compounded into the tread rubber, wet grip performance tends to decrease, and there is room for improvement in the balance of performance among abrasion resistance, snow grip performance, and wet grip performance.

[0005] An object of the present invention is to provide a tire that can improve the overall performance of wear resistance, snow grip performance, and wet grip performance. [Means for solving the problem]

[0006] The present invention relates to a tire having a tread portion, the tread portion being constituted by a rubber composition containing a rubber component, silica, a resin component, and vegetable oil, the rubber component containing 20% ​​by mass or more and 90% by mass or less of styrene-butadiene rubber, the rubber composition containing more than 50 parts by mass and 150 parts by mass or less of silica per 100 parts by mass of the rubber component, the resin component containing at least one selected from the group consisting of terpene resins, C5C9 resins, and dicyclopentadiene resins, the glass transition temperature of the rubber composition being -30°C or less, and wherein t x S is less than 300, where t (mm) is the thickness of the thickest part of the tread portion and S (% by mass) is the styrene content of the styrene-butadiene rubber. [Effects of the Invention]

[0007] According to the present invention, a tire is provided that can improve the overall performance of wear resistance, snow grip performance, and wet grip performance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a tire according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] One embodiment of the present invention relates to a tire having a tread portion, the tread portion being made of a rubber composition including a rubber component, silica, a resin component, and vegetable oil, the rubber component including 20% ​​by mass or more and 90% by mass or less of styrene-butadiene rubber, the rubber composition including more than 50 parts by mass and 150 parts by mass or less of silica per 100 parts by mass of the rubber component, the resin component including at least one resin selected from the group consisting of a terpene resin, a C5C9 resin, and a dicyclopentadiene resin, the glass transition temperature of the rubber composition being -30°C or less, and where t (mm) is the thickness of the thickest part of the tread portion and S (% by mass) is the styrene content of the styrene-butadiene rubber, the tire has a tire having a t×S of less than 300.

[0010] Although not intending to be bound by theory, the mechanism by which the overall performance of wear resistance, snow grip performance, and wet grip performance in the tire of the present invention is improved is thought to be, for example, as follows.

[0011] (1) By setting the glass transition temperature of the rubber composition constituting the tread portion to -30°C or lower, the rigidity of the tread portion at low temperatures is reduced, which is thought to contribute to improving snow grip performance.

[0012] In addition, (2) it is believed that by keeping the content of styrene-butadiene rubber in the tread rubber within a specified range and making the product of the thickness t (mm) of the thickest part of the tread and the styrene content S (mass%) of the styrene-butadiene rubber less than 300, it is possible to reduce the chances of styrene portions coming into contact with each other due to deformation of the tread. This improves wear resistance and reduces the rigidity of the tread at low temperatures, which is believed to contribute to improving snow grip performance.

[0013] Furthermore, (3) it is believed that the dispersibility of silica in the tread rubber can be improved by blending specific resin components and vegetable oil into the tread rubber.

[0014] It is believed that the cooperation of the above (1), (2), and (3) will achieve the remarkable effect of improving the overall performance of wear resistance, snow grip performance, and wet grip performance.

[0015] The styrene-butadiene rubber is preferably extended with a resin component.

[0016] In view of the effects of the present invention, the total amount of the plasticizer per 100 parts by mass of the rubber component is preferably 20 parts by mass or more.

[0017] The total amount of styrene in the rubber component is preferably 20% by mass or less from the viewpoint of abrasion resistance and snow grip performance.

[0018] From the viewpoint of the effects of the present invention, the rubber component preferably contains 10% by mass or more of butadiene rubber.

[0019] From the viewpoint of the effects of the present invention, the rubber component preferably contains 10% by mass or more of an isoprene-based rubber.

[0020] The amount of carbon black per 100 parts by mass of the rubber component is preferably less than 20 parts by mass from the viewpoint of heat buildup.

[0021] From the viewpoint of improving the dispersibility of silica, the rubber composition preferably further contains a liquid resin.

[0022] [Definition] The "tread portion" refers to a component that includes the portion that forms the tire's contact surface, and in a cross section of the tire taken along a plane including the tire rotation axis, if the tire is equipped with components that form the tire skeleton using steel or textile materials, such as a belt layer, a belt reinforcing layer, and a carcass layer, the "tread portion" refers to a component that is located radially outward of these components.

[0023] "Normal condition" refers to a condition in which the tire is mounted on a normal rim and filled with air at normal internal pressure, with no load applied.

[0024] "Genuine rim" refers to the rim specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," for ETRTO (The European Tyre and Rim Technical Organization), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." JATMA, ETRTO, and TRA are referenced in that order, and if an applicable size is available at the time of reference, that standard is followed. In the case of a tire not specified in the above standards, it refers to the narrowest rim among the smallest diameter rims that can be mounted on the tire and can maintain internal pressure (i.e., no air leaks from between the rim and tire).

[0025] "Normal internal pressure" refers to the air pressure specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA, it is "maximum air pressure," for ETRTO, it is "INFLATION PRESSURE," and for TRA, it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims, refer to JATMA, ETRTO, and TRA in that order, and follow that standard if there is an applicable size at the time of reference. In the case of tires not specified in the above standards, it refers to the normal internal pressure (250kPa or more) of another tire size (defined in the standard) that is specified using the regular rim as the standard rim, and if there are multiple normal internal pressures of 250kPa or more listed, it refers to the smallest value among them.

[0026] "Normal load" refers to the load specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA it is "Maximum Load Capacity", for ETRTO it is "Load Capacity", and for TRA it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". As with normal rims and normal internal pressures, JATMA, ETRTO, and TRA should be referenced in that order, and if there is an applicable size at the time of reference, that standard should be followed. For tires not specified in the above standards, the maximum load capacity W calculated separately should be used. L is the normal load.

[0027] "Maximum load capacity W L " is calculated using the following formula: "V" is the virtual volume of the tire (mm 3 ), "Dt" is the outer diameter (mm) of the tire in its normal state, "Ht" is the tire's cross-sectional height (mm) in the tire's radial direction in a cross section of the tire taken along a plane including the tire's rotation axis, and "Wt" is the tire's cross-sectional width (mm) in its normal state. Ht can be calculated by (Dt-R) / 2, where R is the tire rim diameter. Wt is the value obtained by excluding any patterns or letters on the tire sidewall. Note that maximum load capacity is synonymous with the normal load mentioned above.

number

[0028] The "thickness t of the thickest part of the tread portion" is the maximum thickness of the tread portion measured along the normal to the tread surface.

[0029] The "glass transition temperature (Tg) of a rubber composition" is the temperature (tan δ peak temperature) corresponding to the maximum value in the range of -60°C to 60°C on a temperature distribution curve of tan δ measured using a dynamic viscoelasticity measuring device (e.g., an Iplexer series manufactured by GABO) under conditions of a frequency of 10 Hz, an initial strain of 1%, a dynamic strain of ±0.1%, and a heating rate of 2°C / min. In the measurement in the range of -60 to 60°C, if the tan δ value continues to gradually increase or decrease with increasing temperature, the glass transition temperature of the rubber composition is taken to be 60°C or -60°C, respectively. In addition, if there are two or more points showing maximum values ​​in the range of -60°C to 60°C, the lowest temperature point is taken to be the glass transition temperature.

[0030] The "styrene content S of styrene-butadiene rubber" refers to the content of repeating units (styrene units) derived from styrene in styrene-butadiene rubber, and is calculated by pyrolysis gas chromatography. In this specification, "pyrolysis gas chromatography" refers to a method in which a sample is heated in a pyrolysis device, the individual components contained in the gas phase components generated by this heating are separated using a separation column, and each isolated component is analyzed.

[0031] The "vinyl content (amount of 1,2-bonded butadiene units)" is a value calculated by pyrolysis gas chromatography in the same manner as the styrene content, and is applied to rubber components having repeating units derived from butadiene, such as SBR and BR.

[0032] The "cis content (amount of cis-1,4-bonded butadiene units)" is a value calculated by pyrolysis gas chromatography in the same manner as the styrene content, and is applied to rubber components having repeating units derived from butadiene, such as SBR and BR.

[0033] The "total styrene content in the rubber component" refers to the total content (mass%) of styrene units in 100% by mass of the rubber component. This is calculated by multiplying the styrene content (mass%) of each rubber component by its mass fraction in the rubber component, and then adding up the resulting values. Specifically, it is calculated as Σ(styrene content (mass%) of each styrene unit-containing rubber × content (mass%) of each styrene unit-containing rubber in the rubber component / 100). For example, if the rubber component consists of 20% by mass of a first SBR (styrene content: 25% by mass), 30% by mass of a second SBR (styrene content: 27.5% by mass), and 50% by mass of BR, the total styrene content in the rubber component is approximately 13.3% by mass (=(25 × 20 / 100) + (27.5 × 30 / 100) + (0 × 10 / 100)).

[0034] The "weight average molecular weight (Mw)" can be determined by converting the measured value into standard polystyrene equivalents using gel permeation chromatography (GPC) (for example, a GPC-8000 series manufactured by Tosoh Corporation, a differential refractometer as the detector, and a TSKgel (registered trademark) SuperMultiporeHZ-M column manufactured by Tosoh Corporation). This applies to, for example, SBR, BR, plasticizers, etc.

[0035] The "nitrogen adsorption specific surface area (N2SA) of carbon black" is measured in accordance with JIS K 6217-2:2017.

[0036] The "nitrogen adsorption specific surface area (N2SA) of silica" is measured by the BET method in accordance with ASTM D3037-93.

[0037] The "average primary particle size" is a value obtained by photographing particles with a transmission or scanning electron microscope and calculating the arithmetic mean of the particle sizes of 400 particles. If the particle shape is spherical, the particle size is the diameter of the sphere, and if the particle shape is non-spherical, the particle size is calculated from the microscope image as the circle-equivalent diameter (positive square root of {4 × (particle area) / π}).

[0038] The "softening point of the resin component" is the softening point specified in JIS K 6220-1:2015 7.7 measured using a ring and ball softening point tester, and is the temperature at which the ball drops.

[0039] "Plasticizer" is a material that imparts plasticity to rubber components and is a component that is extracted from rubber compositions using acetone. Plasticizers include those that are liquid (fluid) at 25°C and those that are solid at 25°C. However, this does not include waxes and stearic acid, which are commonly used in the tire industry.

[0040] The "total plasticizer content" includes the amount of plasticizer contained in the extended rubber component that has been previously extended with a plasticizer, such as vegetable oil or other oil, a resin component, or a liquid rubber component. The same applies to the oil content, resin component content, and liquid rubber content. For example, if the extended component is oil, the extended oil is included in the oil content.

[0041] A procedure for producing a tire according to one embodiment of the present invention will be described in detail below. However, the following description is merely an example for explaining the present invention, and is not intended to limit the technical scope of the present invention to the scope of this description.

[0042] <Tires> The tire according to the present embodiment has a tread portion made of a rubber composition described below, and is characterized in that, where S (mass%) is the styrene content of the styrene-butadiene rubber contained in the rubber composition and t (mm) is the thickness of the thickest part of the tread portion, t × S is less than 300. The pneumatic tire according to the present embodiment will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and the pneumatic tire according to the present embodiment is not limited to the following embodiment.

[0043] Fig. 1 illustrates a pneumatic tire according to this embodiment. Fig. 1 shows a portion of a cross section of the pneumatic tire taken along a plane including the tire rotation axis. In Fig. 1, the up-down direction is the radial direction of the tire, the left-right direction is the axial direction of the tire, and the direction perpendicular to the paper surface is the circumferential direction of the tire. In Fig. 1, a dashed line CL represents the tire equator.

[0044] As shown in FIG. 1, the tread portion 1 includes a cap rubber layer 11 having circumferential grooves 15 and a tread surface 16, and a base rubber layer 12 laminated on the radially inner side of the cap rubber layer 11. A belt cover layer 6 and a belt layer 5 are disposed on the radially inner side of the tread portion 1. The belt layer 5 is laminated in two layers. The belt cover layer 6 is composed of an edge band 6a that covers only the edge portions of the belt layer 5, and a full band 6b that covers the entire belt layer 5. A carcass 4 and an inner liner 7 are laminated on the radially inner side of the belt layer 5.

[0045] From the viewpoint of the effects of the present invention, the thickness t of the thickest part of the tread portion is preferably 3.0 mm or more, more preferably 4.0 mm or more, even more preferably 5.0 mm or more, and particularly preferably 6.0 mm or more. Also, from the viewpoint of the effects of the present invention, t is preferably 13.0 mm or less, more preferably 12.0 mm or less, and even more preferably 11.0 mm or less.

[0046] (t×S) t×S is less than 300, preferably less than 270, more preferably less than 240, and even more preferably less than 210. On the other hand, the lower limit of t×S is not particularly limited, but is preferably more than 30, more preferably more than 50, and even more preferably more than 70. Note that t and S can be varied independently by a conventional method.

[0047] [Rubber composition] The rubber composition constituting the tread portion according to this embodiment (hereinafter referred to as the rubber composition according to this embodiment) contains a rubber component, silica, a specific resin component, and vegetable oil, has a glass transition temperature of -30°C or lower, and can be produced using the raw materials described below. The rubber composition according to this embodiment will be described below. When the tread portion is composed of two or more layers, the "rubber composition constituting the tread portion" refers to the rubber composition constituting the cap rubber layer 11 having the tread surface 16.

[0048] From the viewpoint of snow grip performance, the glass transition temperature of the rubber composition according to this embodiment is −30° C. or lower, preferably −35° C. or lower, and more preferably −40° C. or lower. On the other hand, the lower limit of the glass transition temperature of the rubber composition is not particularly limited, but is preferably −80° C. or higher, more preferably −70° C. or higher, and even more preferably −60° C. or higher. The Tg of the rubber composition can be appropriately adjusted by the types and amounts of the rubber components, fillers, and plasticizers described below.

[0049] <Rubber component> The rubber component according to the present embodiment contains styrene-butadiene rubber (SBR) as an essential component, and preferably contains SBR and butadiene rubber (BR) and / or isoprene-based rubber, and more preferably contains SBR, BR, and isoprene-based rubber. Alternatively, the rubber component may consist solely of SBR, BR, and isoprene-based rubber.

[0050] (Diene rubber) As the rubber component, a diene rubber is preferably used. Examples of diene rubbers include isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene rubber (SIR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). These diene rubbers may be modified rubbers treated with a modifying group capable of interacting with fillers such as carbon black or silica, or may be hydrogenated rubbers in which some of the unsaturated bonds have been hydrogenated. One type of diene rubber may be used alone, or two or more types may be used in combination. Furthermore, as the diene rubber, an extended rubber that has been previously extended using a plasticizer, as described below, may be used.

[0051] The content of the diene rubber in the rubber component is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The rubber component may also consist solely of the diene rubber.

[0052] (SBR) The SBR is not particularly limited, but examples include unmodified solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs thereof (modified S-SBR, modified E-SBR). Modified SBRs include SBRs whose ends and / or main chains are modified, and modified SBRs (condensates, those having a branched structure, etc.) coupled with tin, silicon compounds, etc. Among these, S-SBR and modified SBR are preferred. Furthermore, hydrogenated products of these SBRs (hydrogenated SBR) can also be used. These SBRs may be used alone or in combination of two or more.

[0053] Among modified SBRs, SBR whose terminals and / or main chains are modified with a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, silicon, and sulfur can be suitably used as ionically modified SBR. Examples of the functional group include an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an amide group, a silyl group, an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms), an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imido group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), a hydroxyl group, an oxy group, and an epoxy group. One or more functional groups selected from the group consisting of an amino group, a carboxyl group, and an alkoxysilyl group are preferred. These functional groups may have a substituent. Examples of the substituent include functional groups such as an amino group, an amide group, an alkoxysilyl group, a carboxyl group, and a hydroxyl group. The modified SBR may be hydrogenated, epoxidized, tin-modified, or the like.

[0054] The SBR according to this embodiment may be SBR extended with a plasticizer (extended SBR), and SBR extended with a resin component is preferably used. Plasticizer-extended SBR can be obtained, for example, by mixing an extender oil composition with unextended SBR by a standard method. The extender oil composition preferably contains oil, and more preferably contains oil and a resin component.

[0055] As the oil in the extender oil composition, any of the oils described below can be used without limitation, but it is preferable that the extender oil composition contains a vegetable oil.

[0056] As the resin component in the extender oil composition, the resin components described below can be used without limitation, but it is preferable that the extender oil composition contains at least one selected from the group consisting of terpene resins, C5C9 resins, and dicyclopentadiene resins.

[0057] When using extended SBR, the amount of SBR extension, i.e., the content of the extended oil composition in the SBR, is preferably 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more, per 100 parts by mass of the rubber solids content of the SBR. The content is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 60 parts by mass or less, and particularly preferably 40 parts by mass or less.

[0058] The content of oil in the extender oil composition is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of rubber solids of SBR, and is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 20 parts by mass or less.

[0059] The content of the resin component in the extender oil composition is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of the rubber solids of the SBR, and is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less.

[0060] From the viewpoint of the effects of the present invention, the styrene content S of SBR is preferably 40% by mass or less, more preferably 36% by mass or less, even more preferably 32% by mass or less, still more preferably 28% by mass or less, and particularly preferably 24% by mass or less. Furthermore, the styrene content S 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. The styrene content S of SBR is measured by the above-mentioned measurement method.

[0061] The vinyl content of SBR is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 12 mol% or more. The vinyl content of SBR is preferably less than 50 mol%, more preferably less than 40 mol%, even more preferably less than 30 mol%, and particularly preferably less than 25 mol%. In this specification, the vinyl content of SBR is measured by the above-mentioned measurement method.

[0062] From the viewpoint of the effects of the present invention, the weight average molecular weight (Mw) of SBR is preferably 100,000 or more, more preferably 300,000 or more, and even more preferably 500,000 or more. From the viewpoint of crosslinking uniformity, the weight average molecular weight is preferably 2,000,000 or less, more preferably 1,800,000 or less, and even more preferably 1,500,000 or less. The weight average molecular weight of SBR is measured by the above-mentioned measurement method.

[0063] From the viewpoint of the present invention, the content of SBR in the rubber component is 20% by mass or more and 90% by mass or less. The content of SBR in the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more. On the other hand, the content of SBR in the rubber component is preferably 85% by mass or less, more preferably 80% by mass or less.

[0064] (BR) The BR is not particularly limited, and can be one commonly used in the tire industry, such as BR with a cis content of less than 50 mol% (low-cis BR), BR with a cis content of 90 mol% 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), modified BR (high-cis modified BR, low-cis modified BR), etc. These BRs may be used alone or in combination of two or more.

[0065] As the high-cis BR, for example, commercially available products from Zeon Corporation, UBE Corporation, JSR Corporation, etc. can be used. The inclusion of high-cis BR can improve low-temperature properties and wear resistance. The cis content of the high-cis BR is preferably more than 95 mol%, more preferably more than 96 mol%, and even more preferably more than 97 mol%. The cis content of BR is measured by the above-mentioned measurement method.

[0066] The rare earth BR is synthesized using a rare earth catalyst and has a vinyl content of preferably less than 1.8 mol%, more preferably less than 1.6 mol%, and even more preferably 1.5 mol% or less, and a cis content of preferably more than 95 mol%, more preferably more than 96 mol%, and even more preferably 97 mol% or more. As the rare earth BR, for example, commercially available products from LANXESS K.K. can be used.

[0067] The SPB-containing BR is not one in which 1,2-syndiotactic polybutadiene crystals are simply dispersed in the BR, but one in which the 1,2-syndiotactic polybutadiene crystals are dispersed after being chemically bonded to the BR. As such SPB-containing BR, commercially available products from UBE Corporation and the like can be used.

[0068] As the modified BR, a modified butadiene rubber (modified BR) in which the terminals and / or the main chain are modified with a functional group containing at least one element selected from the group consisting of silicon, nitrogen, and oxygen can also be suitably used.

[0069] Other examples of modified BR include tin-modified BR, which is obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, and in which the terminals of the modified BR molecule are further bonded with a tin-carbon bond (tin-modified BR).Modified BR may be either non-hydrogenated or hydrogenated.

[0070] From the viewpoint of abrasion resistance, the weight-average molecular weight (Mw) of BR is preferably more than 200,000, more preferably more than 300,000, and even more preferably more than 400,000. From the viewpoint of crosslinking uniformity, etc., it is preferably less than 2,000,000, more preferably less than 1,000,000, and even more preferably less than 800,000. Mw can be determined by the above-mentioned method.

[0071] The content of BR in the rubber component is not particularly limited, but is preferably 1% by mass or more, more preferably 4% by mass or more, even more preferably 7% by mass or more, and particularly preferably 10% by mass or more. On the other hand, the content of BR in the rubber component is preferably 35% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, still more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0072] (Isoprene rubber) The isoprene-based rubber is not particularly limited, and examples thereof include natural rubber (NR), isoprene rubber (IR), modified natural rubber, etc. Examples of NR include SIR20, RSS#3, TSR20, etc. Examples of IR include IR2200, etc. Examples of modified natural rubber include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, grafted natural rubber, etc. These isoprene-based rubbers may be used alone or in combination of two or more.

[0073] The content of the isoprene-based rubber in the rubber component is not particularly limited, but is preferably 1% by mass or more, more preferably 4% by mass or more, even more preferably 7% by mass or more, and particularly preferably 10% by mass or more. On the other hand, the content of the isoprene-based rubber in the rubber component is preferably 35% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0074] (Total styrene content) From the viewpoint of the effects of the present invention, the total styrene content in the rubber component is preferably 28% by mass or less, more preferably 24% by mass or less, even more preferably 20% by mass or less, and particularly preferably 16% by mass or less. Also, from the viewpoint of the effects of the present invention, the total styrene content in the rubber component is preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 6% by mass or more, and particularly preferably 8% by mass or more.

[0075] (Other rubber components) The rubber component may contain a rubber component other than the diene rubber (non-diene rubber) to the extent that it does not affect the effects of the present invention. Examples of non-diene rubbers include rubber components commonly used in the tire industry, such as butyl rubber, 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. In addition to the above rubber components, a known thermoplastic elastomer may or may not be contained.

[0076] (Rubber components synthesized from recycled and biomass-derived raw materials) Monomers, which are structural units of synthetic rubbers such as IR, SBR, and BR, may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene. Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. Among these, recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are preferably used as raw materials.

[0077] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0078] Furthermore, the monomers that are the structural units of polymers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to materials derived from natural resources such as plants. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0079] Monomers derived from biomass (biomass monomers) are not particularly limited, and examples thereof include biomass-derived butadiene and biomass-derived aromatic vinyl compounds. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include, but are not limited to, styrene. The method for producing biomass monomers is not particularly limited, and examples include biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0080] Polymers synthesized from biomass monomer components (biomass polymers) are not particularly limited and include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compounds, etc. Examples of the aromatic vinyl / butadiene copolymers include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0081] Whether a polymer's raw material is biomass-derived can be determined by its pMC (percent modern carbon) measured in accordance with ASTM D6866-10. pMC is the modern standard reference carbon. 14 of sample against C concentration 14 This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0082] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14 C exists. 14 The half-life of C is 5730 years, 14 C is decreasing regularly. Therefore, in the case of fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when they were first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C element.

[0083] on the other hand, 14C is constantly produced by cosmic rays undergoing nuclear reactions in the atmosphere. 14 The amount of C is balanced between radioactive decay and nuclear reaction, and in the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio in a compound can be calculated by using the difference between these values.

[0084] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12 C) is measured. 14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14 The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0085] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, it will usually not reach 100 under normal conditions, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels,14 When the carbon concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC), which corresponds to the above-mentioned biomass ratio of 0%.

[0086] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0087] <Filler> The rubber composition according to the present embodiment contains silica as a filler, and may further contain other fillers such as carbon black. The filler preferably contains carbon black and silica, or may be a filler consisting only of carbon black and silica. The fillers may be used alone or in combination of two or more.

[0088] (silica) The silica is not particularly limited, and can be, for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrated silica), or other silica commonly used in the tire industry. The raw material for silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from a silica-containing product. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. Silica can be used alone or in combination of two or more types.

[0089] As the silica according to the present embodiment, from the viewpoint of building a sustainable society, silica made from a biomass material is preferably used as a raw material. Silica made from a biomass material can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet silica to produce silicon dioxide precipitates, which are then filtered, washed with water, dried, and pulverized.

[0090] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0091] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, the crystallization of silica in rice husk ash can be suppressed (see, for example, JP 2009-2594 A, Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222). Amorphous silica extracted from rice husks can be commercially available from Wilmar, Inc.

[0092] From the viewpoint of reinforcement, the nitrogen adsorption specific surface area (N2SA) of silica is 100m 2 / g or more is preferable, and 120m 2 / g is more preferable, and 150m 2 From the viewpoint of heat buildup and processability, it is more preferable that the tensile strength is more than 300 m / g. 2 / g is preferable, and 280m 2 / g is more preferable, and 250m 2 / g or less is more preferable. The N2SA of silica is measured by the above-mentioned measurement method.

[0093] The average primary particle size of silica is preferably 24 nm or less, more preferably 22 nm or less, even more preferably 20 nm or less, and particularly preferably 18 nm or less.The lower limit of the average primary particle size is not particularly limited, but from the viewpoint of the dispersibility of silica, it is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more.The average primary particle size of silica is measured by the above-mentioned measuring method.

[0094] The content of silica per 100 parts by mass of the rubber component is more than 50 parts by mass, preferably 60 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, still more preferably 90 parts by mass or more, and particularly preferably 100 parts by mass or more, from the viewpoint of abrasion resistance and wet grip performance. Also, the content of silica per 100 parts by mass of the rubber component is 150 parts by mass or less, preferably 140 parts by mass or less, more preferably 130 parts by mass or less, and even more preferably 120 parts by mass or less, from the viewpoint of snow grip performance.

[0095] (carbon black) Carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by thermal decomposition of methane, such as in a thermal black process. Commercially available carbon black 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 Co., Ltd. One type of carbon black may be used alone, or two or more types may be used in combination.

[0096] In addition to the above, from the viewpoint of life cycle assessment, carbon black may be made from a biomass material such as lignin, or recycled carbon black obtained by pyrolysis and purification of a product containing carbon black, such as a tire.

[0097] As used herein, "recycled carbon black" refers to carbon black obtained by crushing used tires or other products containing carbon black and calcining the crushed material, and refers to carbon black in which, when subjected to oxidative combustion by heating in air as measured by thermogravimetry in accordance with JIS K 6226-2:2003, the proportion of the mass of ash (ash content), which is the non-combustible component, is 13% by mass or more. In other words, the proportion of the mass (carbon content) of the recycled carbon black lost due to oxidative combustion is 87% by mass or less. Recycled carbon black is sometimes expressed as rCB.

[0098] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975, citing "Rubber Chemistry and Technology," Vol. 85, No. 3, pp. 408-449 (2012), particularly pp. 438, 440, and 442, describes the carbon black as being obtained by pyrolysis of organic materials at 550-800°C in the absence of oxygen, or by vacuum pyrolysis at relatively low temperatures (

[0027] ). Carbon black obtained from such pyrolysis processes typically lacks functional groups on its surface, as mentioned in

[0004] of Japanese Patent Publication No. 6856781 (Comparison of the Surface Morphology and Chemistry of Pyrolytic Carbon Black with Commercial Carbon Black, Powder Technology 160 (2005) pp. 190-193).

[0099] Recycled carbon black may lack functional groups on its surface, or may be treated to include functional groups on its surface. The treatment to include functional groups on the surface of recycled carbon black can be carried out by conventional methods. For example, in European Patent Application Publication No. 3,173,251, carbon black obtained by a pyrolysis process is treated with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl and / or carboxyl groups on its surface. Furthermore, in Japanese Patent Publication No. 6,856,781, carbon black obtained by a pyrolysis process is treated with an amino acid compound containing at least one thiol or disulfide group to obtain surface-activated carbon black. The recycled carbon black of this embodiment also includes carbon blacks treated to include functional groups on their surfaces.

[0100] As the recycled carbon black, commercially available products from Strable Green Carbon, LD Carbon, etc. can be used.

[0101] The nitrogen adsorption specific surface area (N2SA) of carbon black is 30m from the viewpoint of reinforcement. 2 / g or more is preferable, and 50m 2 / g or more is more preferable, and 70m 2 / g or more is more preferable, and 90m 2 / g or more is particularly preferable. From the viewpoint of fuel economy and processability, 200m 2 / g or less is preferable, and 150m 2 / g or less is more preferable, and 120m 2 / g or less is more preferable.

[0102] The average primary particle size of carbon black is preferably 36 nm or less, more preferably 32 nm or less, even more preferably 28 nm or less, and particularly preferably 24 nm or less. There is no particular lower limit to the average primary particle size, but it is preferably 5 nm or more, more preferably 8 nm or more, and even more preferably 10 nm or more. The average primary particle size of carbon black is measured by the above-mentioned measurement method.

[0103] When carbon black is contained, the content 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, and even more preferably 5 parts by mass or more from the viewpoint of reinforcement, and is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, even more preferably less than 15 parts by mass, and particularly preferably less than 10 parts by mass from the viewpoint of suppressing heat buildup.

[0104] (Other fillers) The filler may contain fillers other than silica and carbon black. The other fillers are not particularly limited, but may include, for example, fillers commonly used in the tire industry, such as aluminum hydroxide, calcium carbonate, alumina, clay, and talc.

[0105] From the viewpoint of the effects of the present invention, the total amount of the filler per 100 parts by mass of the rubber component is preferably 55 parts by mass or more, more preferably 65 parts by mass or more, even more preferably 75 parts by mass or more, still more preferably 85 parts by mass or more, and particularly preferably 95 parts by mass or more. Also, from the viewpoint of the effects of the present invention, the total amount of the filler per 100 parts by mass of the rubber component is preferably 155 parts by mass or less, more preferably 145 parts by mass or less, even more preferably 135 parts by mass or less, and particularly preferably 125 parts by mass or less.

[0106] The silica content in 100% by mass of the filler is preferably more than 50% by mass, more preferably more than 60% by mass, even more preferably more than 70% by mass, even more preferably more than 80% by mass, and particularly preferably more than 90% by mass. The silica content in 100% by mass of the filler is preferably less than 100% by mass, more preferably less than 98% by mass, and even more preferably less than 96% by mass.

[0107] When the filler consists of only carbon black and silica, once the total content of the filler and the content of either the carbon black or the silica are determined as described above, the content of the other will be determined automatically.

[0108] (Silane coupling agent) Silica is preferably used in combination with a silane coupling agent.Silane coupling agent is not particularly limited, but for example, sulfide-based silane coupling agent such as bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide; mercapto-based silane coupling agent such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; vinyl-based silane coupling agent such as vinyltriethoxysilane, vinyltrimethoxysilane; 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane Examples of suitable silane coupling agents include amino-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. Examples of suitable silane coupling agents include those commercially available from Evonik Industries, Momentive, and the like. These silane coupling agents may be used alone or in combination.

[0109] The content of the silane coupling agent relative to 100 parts by mass of silica is preferably 1.0 part by mass or more, more preferably 3.0 parts by mass or more, and even more preferably 5.0 parts by mass or more, from the viewpoint of improving the dispersibility of silica. From the viewpoint of cost and processability, the content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less.

[0110] <Plasticizer> The rubber composition according to the present embodiment contains a resin component and vegetable oil as plasticizers, and may further contain other plasticizers. A plasticizer is a material that imparts plasticity to the rubber component and encompasses both liquid and solid plasticizers at 25°C. Examples of plasticizers include resin components, oils, liquid rubbers, and ester-based plasticizers. These plasticizers may be derived from mineral resources such as petroleum and natural gas, biomass-derived plasticizers, or naphtha recycled from rubber and non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. One type of plasticizer may be used alone, or two or more types may be used in combination.

[0111] (resin component) The resin component used in this embodiment includes at least one selected from the group consisting of terpene-based resins, C5C9-based resins, and dicyclopentadiene-based resins, and may further include other resin components.

[0112] The other resin components are not particularly limited as long as they are resins commonly used in the tire industry, and examples thereof include adhesive resins such as aromatic vinyl resins, C9 resins, C5 resins, rosin resins, phenolic resins, etc. These other resin components may be used alone or in combination of two or more.

[0113] <Terpene resin> Terpene resins refer to resins containing at least one terpene compound selected from the group consisting of α-pinene, β-pinene, limonene, dipentene, etc., as the largest content of the monomer component, and may be hydrogenated or modified. Specific examples of terpene resins include polyterpene resins containing only one or more of the terpene compounds as monomer components; aromatic-modified terpene resins containing the terpene compound and an aromatic compound as monomer components; and terpene phenolic resins containing the terpene compound and a phenolic compound as monomer components. Examples of aromatic compounds that serve as monomer components for aromatic-modified terpene resins include at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include at least one selected from the group consisting of phenol, bisphenol A, cresol, xylenol, etc. These terpene resins may be used alone or in combination.

[0114] <Dicyclopentadiene resin> The term "dicyclopentadiene-based resin" refers to a resin containing dicyclopentadiene (DCPD) as a monomer component, and may be hydrogenated or modified. Examples of dicyclopentadiene-based resins include DCPD / C9 resins containing dicyclopentadiene and the C9 fraction described below as monomer components (the DCPD / C9 resins may be hydrogenated or modified). DCPD resins that can be used include those commercially available from ExxonMobil Corporation, ENEOS Corporation, Nippon Zeon Co., Ltd., Maruzen Petrochemical Co., Ltd., etc. These dicyclopentadiene-based resins may be used alone or in combination of two or more.

[0115] <Aromatic vinyl resin> The term "aromatic vinyl resin" refers to a resin containing at least one aromatic vinyl compound selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, etc., as the monomer component with the highest content, and may be a hydrogenated or modified version of such a compound. As the aromatic vinyl resin, a homopolymer of α-methylstyrene or styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, because they are economical, easy to process, and have excellent heat generation properties. As the aromatic vinyl resin, for example, commercially available products from Kraton, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used. These aromatic vinyl resins may be used alone or in combination of two or more.

[0116] <C9 resin> The term "C9 resin" refers to a resin obtained by polymerizing a C9 fraction. It may be a C9 fraction polymerized alone or a copolymer obtained by copolymerizing a C9 fraction with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with a C9 fraction is called a DCPD / C9 resin. These resins may also be hydrogenated or modified. Examples of C9 fractions include at least one petroleum fraction having 8 to 10 carbon atoms selected from the group consisting of vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene. Specific examples of C9 resins include coumarone-indene resin, coumarone resin, and indene resin. These C9 resins may be used alone or in combination.

[0117] <C5 resin> "C5 resin" refers to a resin obtained by polymerizing a C5 fraction other than dicyclopentadiene, and may be a hydrogenated or modified version of such a resin. Examples of C5 fractions other than dicyclopentadiene include at least one petroleum fraction having 4 to 5 carbon atoms selected from the group consisting of cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, pentadiene, etc. These C5 resins may be used alone or in combination of two or more.

[0118] <C5C9 resin> The term "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be a hydrogenated or modified resin. As the C5C9 resin, for example, commercially available resins from Tosoh Corporation, LUHUA, etc. may be used. These C5C9 resins may be used alone or in combination of two or more.

[0119] <Rosin-based resin> The rosin-based resin refers to a resin containing at least one rosin acid compound selected from the group consisting of abietic acid, neoabietic acid, palustric acid, isopimaric acid, etc., and may be a hydrogenated or modified version of such a rosin-based resin. Examples of the rosin-based resin include, but are not limited to, natural rosin and rosin-modified resins obtained by modifying rosin through hydrogenation, disproportionation, dimerization, esterification, etc. These rosin-based resins may be used singly or in combination of two or more.

[0120] <Phenol-based resin> The phenolic resin refers to a resin that contains a phenolic compound such as phenol or cresol as the monomer component with the highest content. Examples of the phenolic resin include, but are not limited to, phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, and oil-modified phenol formaldehyde resin. These phenolic resins may be used alone or in combination of two or more.

[0121] From the viewpoint of the effects of the present invention, the softening point of the resin component is preferably above 50° C., more preferably above 60° C., even more preferably above 70° C., and particularly preferably above 80° C. Furthermore, from the viewpoint of improving processability and dispersibility of the rubber component and the filler, the softening point is preferably below 150° C., more preferably below 140° C., and even more preferably below 130° C. The softening point of the resin component is measured by the above-mentioned measurement method.

[0122] <Liquid resin> A liquid resin can also be used as the resin component. The liquid resin is not particularly limited as long as it is a resin that is in a liquid state at 25°C, and examples thereof include liquid aromatic vinyl resins, liquid C9 resins, and liquid coumarone-indene resins. The liquid resins may be used alone or in combination of two or more.

[0123] The content of the resin components (preferably the total content of the terpene resin, C5C9 resin, and dicyclopentadiene resin) per 100 parts by mass of the rubber component is, from the viewpoint of the effects of the present invention, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more. From the viewpoint of suppressing heat buildup, the content is preferably less than 60 parts by mass, more preferably less than 50 parts by mass, even more preferably less than 40 parts by mass, and particularly preferably less than 35 parts by mass. The content of the resin components also includes the amount of the resin components contained in the extended rubber component.

[0124] (oil) The oil used in this embodiment includes vegetable oil, and may further include other oils. The oils may be used alone or in combination of two or more.

[0125] ≪Vegetable oil≫ As used herein, examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above-mentioned oils, interesterified oils obtained by interesterifying the above-mentioned oils, hardened oils obtained by hydrogenating the above-mentioned oils, thermally polymerized oils obtained by thermally polymerizing the above-mentioned oils, oxidatively polymerized oils obtained by oxidizing the above-mentioned oils, and waste edible oils recovered from edible oils and the like. Vegetable oils may be liquid or solid at 25°C. These vegetable oils may be used alone or in combination of two or more.

[0126] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is esterified with a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. The acylglycerol may be liquid or solid at 25°C.

[0127] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, the 1When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0128] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0129] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., saturated fatty acid or monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing saturated fatty acid or monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0130] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0131] From the viewpoint of the effects of the present invention, the content of vegetable oil per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more. From the viewpoint of suppressing heat buildup, the content is preferably less than 70 parts by mass, more preferably less than 60 parts by mass, even more preferably less than 50 parts by mass, and particularly preferably less than 40 parts by mass. The oil content also includes the amount of vegetable oil contained in the extended rubber component.

[0132] Other oils include, for example, mineral oil and animal oil. From the viewpoint of life cycle assessment, waste oils used in rubber mixers and engines, and refined waste cooking oils used in restaurants may also be used. One type of oil may be used alone, or two or more types may be used in combination.

[0133] As used herein, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil. Specific examples of mineral oil include mild extracted solvate (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, as an environmental measure, oils with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of low PCA oils include MES, TDAE, and heavy naphthenic oil.

[0134] Examples of animal oils include fish oil, beef tallow, whale oil, and oleyl alcohol derived from these.

[0135] From the viewpoint of the effects of the present invention, the total content of oil per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more. From the viewpoint of suppressing heat buildup, the total content of oil is preferably less than 70 parts by mass, more preferably less than 60 parts by mass, even more preferably less than 50 parts by mass, and particularly preferably less than 40 parts by mass. The oil content includes the amount of oil contained in the extended rubber component.

[0136] (liquid rubber) The liquid rubber is not particularly limited as long as it is a polymer that is in a liquid state at 25° C., and examples thereof include liquid butadiene rubber (liquid BR), liquid styrene butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene isoprene rubber (liquid SIR), liquid farnesene rubber, etc. One type of liquid rubber may be used alone, or two or more types may be used in combination.

[0137] (ester plasticizer) Examples of ester-based plasticizers include dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), di-2-ethylhexyl azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), diundecyl phthalate (DUP), dibutyl phthalate (DBP), dioctyl sebacate (DOS), tributyl phosphate (TBP), trioctyl phosphate (TOP), triethyl phosphate (TEP), trimethyl phosphate (TMP), thymidine triphosphate (TTP), tricresyl phosphate (TCP), and trixylenyl phosphate (TXP). One type of ester-based plasticizer may be used alone, or two or more types may be used in combination.

[0138] From the viewpoint of the effects of the present invention, the total content of the plasticizers 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 particularly preferably 45 parts by mass or more. From the viewpoint of suppressing heat buildup, the content is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass.

[0139] <Other compounding agents> In addition to the above components, the rubber composition according to the present embodiment may contain compounding agents that are generally used in the tire industry, such as vulcanized rubber particles, processing aids, waxes, antioxidants, stearic acid, zinc oxide, vulcanizing agents, and vulcanization accelerators, as appropriate.

[0140] (vulcanized rubber particles) The vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. One type of vulcanized rubber particle may be used alone, or two or more types may be used in combination.

[0141] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0142] As commercially available vulcanized rubber, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., etc. can be used.

[0143] (processing aids) Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. These processing aids may be used alone or in combination of two or more. Examples of processing aids that can be used include those commercially available from Schill + Seilacher, Performance Additives, etc.

[0144] When a processing aid is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of improving processability, and is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance and breaking strength.

[0145] (wax) The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used, such as mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral waxes are preferred. Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. The wax according to this embodiment does not contain stearic acid. Waxes commercially available from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., etc. can be used. One type of wax may be used alone, or two or more types may be used in combination.

[0146] When wax is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of weather resistance of the rubber, and is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of preventing whitening of the tire due to bloom.

[0147] (anti-aging agent) The antioxidant is not particularly limited, but examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants 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 (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl ... p-phenylenediamine-based antioxidants such as diphenyldiamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; 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. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., and Flexis Co., Ltd. One type of antioxidant may be used alone, or two or more types may be used in combination.

[0148] When an antioxidant is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of ozone crack resistance of the rubber, and is preferably less than 5.0 parts by mass, more preferably less than 4.0 parts by mass, and even more preferably less than 3.0 parts by mass from the viewpoint of abrasion resistance and wet grip performance.

[0149] (stearic acid) When stearic acid is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of processability, and is preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of vulcanization rate.

[0150] (zinc oxide) When zinc oxide is contained, the content per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1.0 part by mass, and even more preferably more than 1.5 parts by mass from the viewpoint of processability, and preferably less than 10 parts by mass, more preferably less than 7.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance.

[0151] (vulcanizing agent) Sulfur is preferably used as the vulcanizing agent. Examples of sulfur that can be used include powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. The vulcanizing agent may be used alone or in combination of two or more.

[0152] When sulfur is contained, the content per 100 parts by mass of the rubber component is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, from the viewpoint of ensuring a sufficient vulcanization reaction. Furthermore, from the viewpoint of preventing deterioration, the content is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less. When oil-containing sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is the total content of pure sulfur contained in the oil-containing sulfur.

[0153] Known organic crosslinking agents can also be used as vulcanizing agents other than sulfur. The organic crosslinking agent is not particularly limited as long as it can form crosslinked chains other than polysulfide bonds. Examples of the organic crosslinking agent include alkylphenol-sulfur chloride condensate, sodium 1,6-hexamethylene-dithiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, and dicumyl peroxide. 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane is preferred. These organic crosslinking agents can be commercially available from Taoka Chemical Co., Ltd., Lanxess K.K., Flexis, and other companies.

[0154] (Vulcanization accelerator) The vulcanization accelerator is not particularly limited, but examples thereof include sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, guanidine vulcanization accelerators, thiuram vulcanization accelerators, thiourea vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehyde-amine vulcanization accelerators, aldehyde-ammonia vulcanization accelerators, imidazoline vulcanization accelerators, xanthate vulcanization accelerators, and caprolactam disulfide. These vulcanization accelerators may be used alone or in combination of two or more. Among them, one or more vulcanization accelerators selected from the group consisting of sulfenamide vulcanization accelerators, thiazole vulcanization accelerators, and guanidine vulcanization accelerators are preferred, as they more suitably achieve the desired effects. The vulcanization accelerators may be used alone or in combination of two or more.

[0155] Examples of sulfenamide vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS).

[0156] Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole (MBT) or a salt thereof, di-2-benzothiazolyl disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinothio)benzothiazole.

[0157] Examples of guanidine vulcanization accelerators include 1,3-diphenylguanidine (DPG), 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, and 1,3-di-o-cumenyl-2-propionylguanidine.

[0158] When a vulcanization accelerator is contained, the content per 100 parts by mass of the rubber component is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2.0 parts by mass or more, from the viewpoint of ensuring a sufficient vulcanization rate. The content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, and even more preferably 6.0 parts by mass or less. By setting the content of the vulcanization accelerator within the above range, breaking strength and elongation tend to be ensured.

[0159] In this specification, various materials containing carbon atoms (for example, rubber, oil, resin components, vulcanization accelerators, antioxidants, surfactants, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining such various materials from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0160] [Production of rubber composition and tire] The rubber composition according to the present embodiment can be produced by a known method. For example, it can be produced by kneading the above-mentioned components using a rubber kneading device such as an open roll or an internal kneader (e.g., a Banbury mixer or a kneader). The kneading process may include, for example, a base kneading process in which compounding ingredients and additives other than the vulcanizing agent and vulcanization accelerator are kneaded, and a final kneading (F kneading) process in which the vulcanizing agent and vulcanization accelerator are added to the kneaded product obtained in the base kneading process and kneaded. Furthermore, the base kneading process can be divided into multiple processes as desired.

[0161] The kneading conditions are not particularly limited, but examples include a method in which the base kneading step involves kneading for 3 to 10 minutes at a discharge temperature of 150 to 170°C, and a method in which the final kneading step involves kneading for 1 to 5 minutes at 70 to 110°C. The vulcanization conditions are not particularly limited, but examples include a method in which vulcanization is carried out for 10 to 30 minutes at 150 to 200°C.

[0162] The tire according to the present embodiment, which has a tread portion made of the rubber composition, can be manufactured by a conventional method. That is, an unvulcanized rubber composition obtained by blending the above-mentioned components with a rubber component as needed is extruded to match the shape of the corresponding tread portion, and then bonded together with other tire components in a tire building machine and molded by a conventional method to form an unvulcanized tire. The unvulcanized tire is then heated and pressurized in a vulcanizer to manufacture the tire. The vulcanization conditions are not particularly limited, and examples include a method of vulcanizing at 150 to 200°C for 10 to 30 minutes.

[0163] <Application> In this specification, the tire can be used for any purpose, regardless of whether it is a pneumatic tire or a non-pneumatic tire, and can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a racing tire, a motorcycle tire, a heavy-duty tire, or a run-flat tire. Passenger car tires are tires designed to be mounted on four-wheeled vehicles and have a maximum load capacity of less than 1,400 kg. Heavy-duty tires are tires with a maximum load capacity of 1,400 kg or more. In this specification, the tire can be used as an all-season tire, a summer tire, or a winter tire such as a studless tire. [Example]

[0164] The following examples (working examples) are considered to be preferable for carrying out the present invention, but the scope of the present invention is not limited to these examples. Tires having tread portions obtained according to the formulations in Tables 2 and 3 using the various chemicals shown below were examined, and the results calculated based on the evaluation methods described below are shown in Tables 2 and 3.

[0165] NR:RSS#3 SBR1 to 5: Extended SBR produced according to the following production examples BR: UBEPOL BR (registered trademark) 150B (unmodified BR, cis content: 97% by mass, Mw: 440,000) manufactured by UBE Corporation Carbon black: Diablack I (N220, N2SA: 114m) manufactured by Mitsubishi Chemical Corporation 2 / g, average primary particle diameter: 22nm) Silica: ULTRASIL VN3 (N2SA: 175 ml) manufactured by Evonik Industries 2 / g, average primary particle diameter: 18nm) Silane coupling agent: Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) manufactured by Evonik Industries Vegetable oil: Kaneda Industrial Soybean Oil Resin component 1: Kraton SYLVATARAXX 4150 (polyterpene resin, softening point: 115°C) Resin component 2: ExxonMobil Oppa PR395 (hydrogenated DCPD / C9 resin, softening point: 118°C) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Antioxidant: Nocrac 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: Camellia stearic acid beads manufactured by NOF Corporation Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela CZ-G (N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccelaer D (1,3-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0166] (Production example: Production of SBR1 to 5) Cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were charged into a nitrogen-purged autoclave reactor. The ratio of styrene to 1,3-butadiene was adjusted so that the styrene content was the mass % shown in Table 1. The temperature of the reactor contents was adjusted to 20°C, and n-butyllithium was added to initiate polymerization. Polymerization was carried out under adiabatic conditions. When the polymerization conversion reached 99%, additional 1,3-butadiene was added. After an additional 5 minutes of polymerization, 3-diethylaminopropyltriethoxysilane was added as a modifier to modify the polymer. After the polymerization reaction was completed, 2,6-di-tert-butyl-p-cresol was added, followed by steam stripping to remove the solvent and drying on a heated roll to obtain unextended S-SBR. Then, an extended oil composition prepared by mixing 100 parts by mass of unextended S-SBR with resin component 1 (SYLVATARAXX4150 manufactured by Kraton) and vegetable oil (industrial soybean oil manufactured by Kaneda Co., Ltd.) in the proportions shown in Table 1 was added to each of the unextended S-SBR to obtain SBRs 1 to 5.

[0167] [Table 1]

[0168] Examples and Comparative Examples According to the compounding formulations shown in Tables 2 and 3, a 1.7 L closed-type Banbury mixer is used to knead the chemicals other than sulfur and the vulcanization accelerator for 1 to 10 minutes until the discharge temperature reaches 150 to 160°C, yielding a kneaded mixture. Next, a two-screw open roll mill is used to add sulfur and the vulcanization accelerator to the kneaded mixture, which is then kneaded for 4 minutes until the temperature reaches 105°C, yielding an unvulcanized rubber composition. The resulting unvulcanized rubber composition is molded to fit the shape of the tread, bonded together with other tire components, and formed into an unvulcanized tire. The tire is then press-vulcanized at 150°C for 35 minutes to yield the test tires (size: 195 / 65R15) shown in Tables 2 and 3.

[0169] <Measurement of glass transition temperature (Tg) of rubber composition> Each rubber test piece is cut out from the tread portion of each test tire to a length of 20 mm, width of 4 mm, and thickness of 1 mm, with the long side aligned in the tire circumferential direction and the thickness direction aligned in the tire radial direction. Using a dynamic viscoelasticity measuring device (GABO's Iplexer series) under conditions of a frequency of 10 Hz, an initial strain of 1%, a dynamic strain of ±0.1%, and a heating rate of 2°C / min, a temperature distribution curve of tan δ is measured in the range of -60°C to 60°C, and the temperature corresponding to the largest tan δ value in the obtained temperature distribution curve (tan δ peak temperature) is determined as the Tg of the rubber composition.

[0170] <Wear resistance> Each test tire was fitted to all wheels of a vehicle (domestic FF 2000cc), and the tread groove depth was measured after driving 15,000 km on paved roads, and the distance traveled when the groove depth decreased by 1 mm was calculated. The distance traveled by the control tire (Comparative Example 1) was set at 100, and the wear resistance of each tire was expressed as an index using the following formula. The higher the index, the better the wear resistance. (Wear resistance performance index) = (travel distance of each test tire) / (travel distance of control tire) × 100

[0171] <Snow grip performance> Each test tire was fitted to all wheels of a vehicle (domestic FF 2000cc), and the braking distance was measured from the point where the brakes were applied at a speed of 30 km / h on a road surface with a snowy temperature of -2 to -10°C. The braking distance of the control tire (Comparative Example 1) was set at 100, and the reciprocal of the braking distance of each test tire was expressed as an index using the following formula. A higher index indicates better snow grip performance. (Snow grip performance index) = (braking distance of control tire) / (braking distance of each test tire) × 100

[0172] <Wet grip performance> Each test tire was fitted to all wheels of a vehicle (domestic FF 2000cc), and the braking distance was measured from the point where the brakes were applied at a speed of 100 km / h on a wet asphalt road surface. The braking distance of the control tire (Comparative Example 1) was set at 100, and the reciprocal of the braking distance of each test tire was expressed as an index using the following formula. A higher index indicates better wet grip performance. (Wet grip performance index) = (braking distance of control tire) / (braking distance of each test tire) × 100

[0173] <Overall performance> The total value of the abrasion resistance performance index, snow grip performance index, and wet grip performance index is shown as the overall performance index.

[0174] [Table 2]

[0175] [Table 3]

[0176] <Embodiment> Examples of embodiments of the present invention are given below.

[0177] [1] A tire having a tread portion, the tread portion being composed of a rubber composition containing a rubber component, silica, a resin component, and vegetable oil, the rubber component containing 20% ​​by mass or more and 90% by mass or less of styrene-butadiene rubber, the rubber composition containing more than 50 parts by mass and 150 parts by mass or less of silica per 100 parts by mass of the rubber component, the resin component containing at least one selected from the group consisting of terpene resin, C5C9 resin, and dicyclopentadiene resin, the glass transition temperature of the rubber composition being -30°C or less, and where t (mm) is the thickness of the thickest part of the tread portion and S (mass%) is the styrene content of the styrene-butadiene rubber, t × S is less than 300, preferably more than 30 and less than 270, more preferably more than 50 and less than 240. [2] The tire according to [1] above, wherein the styrene-butadiene rubber is extended with a resin component. [3] The tire according to the above [1] or [2], wherein the total content of the plasticizer per 100 parts by mass of the rubber component is 20 parts by mass or more, preferably 40 parts by mass or more but less than 80 parts by mass. [4] The tire according to any one of the above [1] to [3], wherein the total amount of styrene in the rubber component is 20% by mass or less, preferably from 2% by mass to 20% by mass. [5] The tire according to any one of the above [1] to [4], wherein the rubber component contains 10% by mass or more, preferably 10% by mass or more and 35% by mass or less, of butadiene rubber. [6] The tire according to any one of the above [1] to [5], wherein the rubber component contains 10% by mass or more, preferably 10% by mass or more and 35% by mass or less, of an isoprene-based rubber. [7] The tire according to any one of the above [1] to [6], wherein the rubber component contains 50% by mass or more and 90% by mass or less of styrene-butadiene rubber. [8] The tire according to any one of the above [1] to [7], wherein the rubber composition contains 80 parts by mass or more and 150 parts by mass or more of silica per 100 parts by mass of the rubber component. [9] The tire according to any one of the above [1] to [8], wherein the amount of carbon black per 100 parts by mass of the rubber component is less than 20 parts by mass, preferably 1 part by mass or more and less than 10 parts by mass.

[10] The tire according to any one of the above [1] to [9], wherein the resin component contains a liquid resin. [Explanation of symbols]

[0178] 1 Tread section 4. Carcass 5 Belt Layer 6 Belt cover layer 6a Edge Band 6b full band 7 Inner liner 11 Cap rubber layer 12 Base rubber layer 15 Circumferential groove 16 Tread surface CL Tire Equator t Thickness of the thickest part of the tread

Claims

1. A tire having a tread portion, the tread portion is made of a rubber composition containing a rubber component, silica, a resin component, and vegetable oil, The rubber component contains 20% by mass or more and 90% by mass or less of styrene-butadiene rubber, The rubber composition contains more than 50 parts by mass and 150 parts by mass or less of silica per 100 parts by mass of the rubber component, the resin component includes at least one selected from the group consisting of a terpene-based resin, a C5C9-based resin, and a dicyclopentadiene-based resin; The glass transition temperature of the rubber composition is −30° C. or lower, The tire has a t×S value of less than 300, where t (mm) is the thickness of the thickest part of the tread portion and S (mass%) is the styrene content of the styrene-butadiene rubber.

2. 2. The tire according to claim 1, wherein the styrene-butadiene rubber is extended with a resin component.

3. The tire according to claim 1 or 2, wherein a total content of the plasticizers per 100 parts by mass of the rubber component is 20 parts by mass or more.

4. The tire according to claim 1 or 2, wherein the total amount of styrene in the rubber component is 20% by mass or less.

5. The tire according to claim 1 or 2, wherein the rubber component contains 10% by mass or more of butadiene rubber.

6. The tire according to claim 1 or 2, wherein the rubber component contains 10% by mass or more of an isoprene-based rubber.

7. The tire according to claim 1 or 2, wherein the rubber component contains 50% by mass or more and 90% by mass or less of styrene-butadiene rubber.

8. The tire according to claim 1 or 2, wherein the rubber composition contains 80 parts by mass or more and 150 parts by mass or more of silica per 100 parts by mass of the rubber component.

9. The tire according to claim 1 or 2, wherein an amount of carbon black per 100 parts by mass of the rubber component is less than 20 parts by mass.

10. The tire according to claim 1 or 2, wherein the resin component contains a liquid resin.

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