Tire

Abstract

To provide a tire for improving total performance of on-ice performance and wet grip performance.SOLUTION: A tire comprising a tread portion, the tread portion being formed from a rubber composition containing a rubber component, a filler containing silica, and a plasticizer, the rubber component containing more than 5% by mass and less than 50% by mass of a styrene-butadiene rubber, the rubber component contains an isoprene-based rubber and / or a butadiene rubber, a total content of the isoprene-based rubber and the butadiene rubber in the rubber component is more than 50% by mass, and a total styrene content S (% by mass) in the rubber component is less than 10, A content of the silica is more than 50 parts by mass based on 100 parts by mass of rubber components, the plasticizing agent contains C5 resins and / or C9 resins, a total content P (parts by mass) of the plasticizing agent is more than 40 parts by mass based on 100 parts by mass of the rubber components, and the tread portion includes two or more circumferential grooves and two or more lateral grooves, and one or more blocks defined by the circumferential grooves and the lateral grooves.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, there has been a demand for tires with improved performance on ice. For example, Patent Document 1 describes a tire that has blocks in the tread portion separated by lateral grooves, sipes in the blocks that are inclined in the opposite direction to the lateral grooves, and the sipes have portions that are deeper and shallower than the lateral grooves, thereby demonstrating excellent performance on ice and snow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-195050 Summary of the Invention [Problem to be solved by the invention]

[0004] Tires are being asked to not only further improve their performance on ice, but also to improve their wet grip performance.

[0005] An object of the present invention is to provide a tire that has improved overall performance, including ice performance and wet grip performance. [Means for solving the problem]

[0006] The present invention provides A tire having a tread portion, the tread portion is composed of a rubber composition containing a rubber component, a filler containing silica, and a plasticizer, The rubber component includes a styrene-butadiene rubber, The content of the styrene-butadiene rubber in the rubber component is more than 5% by mass and less than 50% by mass, the rubber component contains an isoprene-based rubber and / or a butadiene rubber, the total content of the isoprene-based rubber and the butadiene rubber in the rubber component is more than 50% by mass, The total styrene content S (mass%) in the rubber component is less than 10, The content of the silica per 100 parts by mass of the rubber component is more than 50 parts by mass, the plasticizer contains a C5 resin and / or a C9 resin, The total content P (parts by mass) of the plasticizer relative to 100 parts by mass of the rubber component is more than 40, the tread portion has two or more circumferential grooves, two or more lateral grooves, and one or more blocks defined by at least the circumferential groove and the lateral groove, At least one of the blocks has two or more sipes, The average value D of the sipe densities in all blocks having two or more sipes is greater than 0.005, A tire, wherein S, P, and D satisfy the following formulas: (1) P × D × S > 2.00 [Effects of the Invention]

[0007] According to the present invention, a tire is provided which has improved overall performance in terms of ice performance and wet grip performance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a development view of a tire contact patch of a tire according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a tire according to one embodiment of the present invention will be described. The tire according to this embodiment has a tread portion, and the tread portion is made of a rubber composition containing a rubber component, a filler containing silica, and a plasticizer, the rubber component contains styrene-butadiene rubber, and the content of the styrene-butadiene rubber in the rubber component is more than 5% by mass and less than 50% by mass, the rubber component contains isoprene-based rubber and / or butadiene rubber, the total content of the isoprene-based rubber and butadiene rubber in the rubber component is more than 50% by mass, the total styrene content S (mass%) in the rubber component is less than 10, and the silica content is 100 parts by mass of the rubber component. the plasticizer contains a C5 resin and / or a C9 resin, the total content P (parts by mass) of the plasticizer per 100 parts by mass of the rubber component is greater than 40, the tread portion has two or more circumferential grooves and two or more lateral grooves, and one or more blocks defined by at least the circumferential groove and the lateral groove, at least one of the blocks has two or more sipes, an average value D of sipe densities in all the blocks having the two or more sipes is greater than 0.005, and the S, the P, and the D satisfy the following formula: (1) P × D × S > 2.00

[0010] Although not intending to be bound by theory, the reason why the overall performance of ice performance and wet grip performance is improved in the present invention is thought to be as follows.

[0011] Specifically, (1) the rubber composition constituting the tread portion contains styrene-butadiene rubber in a content of more than 5% by mass but less than 50% by mass, and the total content of isoprene-based rubber and butadiene rubber exceeds 50% by mass. This is believed to contribute to overall improvement in ice performance and wet grip performance. (2) The total styrene content (S) in the rubber component is less than 10% by mass, resulting in the formation of minute styrene domains in the rubber matrix. These minute domains are flexible, improving the polymer mobility and road-following ability of the rubber composition, which is believed to contribute to improved wet grip performance. (3) The inclusion of more than 50 parts by mass of silica per 100 parts by mass of the rubber component is believed to contribute to improved wet grip performance. (4) The inclusion of a C5 resin and / or a C9 resin contributes to overall improvement in ice performance and wet grip performance. (5) The total plasticizer content (P) per 100 parts by mass of the rubber component is more than 40 parts by mass, contributing to overall improvement in ice performance and wet grip performance. (6) The average sipe density D in all blocks having sipes exceeds 0.005, which contributes to improving the overall performance of ice and wet grip performance. (7) The ratio P x D x S exceeds 2.00, which contributes to improving the overall performance of ice and wet grip performance. It is believed that the cooperation of the above (1) to (7) achieves the remarkable effect of improving the overall performance of ice and wet grip performance.

[0012] Preferably, the plasticizer further contains vegetable oil.

[0013] It is believed that the vegetable oil improves the dispersibility of silica, further improving ice performance and wet grip performance.

[0014] Preferably, the silica comprises biomass silica.

[0015] Biomass silica is believed to further improve ice and wet grip performance.

[0016] Preferably, the filler comprises recycled carbon black.

[0017] Recycled carbon black is believed to further improve ice and wet grip performance.

[0018] The rubber composition preferably contains vulcanized rubber particles.

[0019] The vulcanized rubber particles are believed to further improve ice and wet grip performance.

[0020] At least one of the sipes preferably extends in a zigzag pattern in the depth direction of the sipe.

[0021] It is believed that the effects of the present invention are further enhanced by the sipes extending in a zigzag pattern in the depth direction.

[0022] The sipes preferably include tie bars protruding from the bottoms thereof radially outward in the tire direction.

[0023] The inclusion of tie bars in the sipes is believed to further improve performance on ice.

[0024] The height of the tie bar in the tire radial direction is preferably 40 to 70% of the depth of the deepest part of the sipe.

[0025] It is believed that performance on ice is further improved by setting the height of the tie bars in the tire radial direction to 40 to 70% of the depth of the deepest part of the sipes.

[0026] It is preferable that the sipes extend in a zigzag pattern in the length direction thereof, and that the width of the tie bars in the tire axial direction is 10 to 40% of the entire length of the sipes.

[0027] It is believed that performance on ice will be further improved if the width of the tie bar in the axial direction of the tire is 10 to 40% of the total length of the sipe.

[0028] It is preferable that S, P, and D satisfy the following formula: (2) P × D / S > 0.020

[0029] It is believed that a P×D / S ratio of more than 0.020 further improves the overall performance of ice performance and wet grip performance.

[0030] It is preferable that the S and P satisfy the following formula: (3) P / S>4.00

[0031] It is believed that a P / S of over 4.00 will further improve the overall performance of ice performance and wet grip performance.

[0032] The content of oil in the plasticizer is preferably 60% by mass or more.

[0033] It is believed that the wet grip performance is further improved when the oil content in the plasticizer is 60% by mass or more.

[0034] The tire according to the present embodiment is preferably a studless tire.

[0035] [Definition] "Normal condition" means that the tire is mounted on a normal rim, inflated to the normal internal pressure, and unloaded. Unless otherwise specified, the tire must be in normal condition.

[0036] "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).

[0037] "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.

[0038] "Normal load (kg)" is the load specified for each tire in the standard system including the standard on which the tire is based, for example, "Maximum Load Capacity" for JATMA, "Load Capacity" for ETRTO, and the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA. 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.

[0039] "Maximum load capacity W L (kg)" 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.

[0040]

number

[0041] 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.

[0042] The "total styrene content (S) in the rubber component" refers to the total content (mass%) of styrene moieties in 100% by mass of the rubber component. This is calculated by multiplying the styrene content (mass%) of each rubber component by the 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-containing rubber in the rubber component / 100). For example, if the rubber component consists of 30% by mass of a first SBR (styrene content: 25% by mass), 60% by mass of a second SBR (styrene content: 27.5% by mass), and 10% by mass of BR, the total styrene content (S) in 100% by mass of the rubber component is 24.0% by mass (= 25 × 30 / 100 + 27.5 × 60 / 100 + 0 × 10 / 100).

[0043] A "sipe" is a recess formed on the tread surface of a tire (extending radially inward) with an opening width on the tread surface of less than 2.0 mm. A recess with an opening width of 2.0 mm or more is called a "groove."

[0044] The term "circumferential groove" refers to a groove that extends continuously in the circumferential direction of the tire. The circumferential groove may extend linearly along the circumferential direction, or may extend in a wavy, sinusoidal, or zigzag pattern along the circumferential direction.

[0045] A "lateral groove" is a groove extending in the tire width direction. The lateral groove may have both ends or one end connected to the tread edge or the circumferential groove, or may be a closed lateral groove that does not communicate with the tread edge or the circumferential groove.

[0046] A "block" is an area defined by at least a circumferential groove and a lateral groove. At least one end of the lateral groove defining the block is connected to a circumferential groove or a tread edge. In this specification, the term "block" includes both so-called shoulder blocks defined by a tread edge, one circumferential groove, and a lateral groove, and so-called crown blocks defined by two circumferential grooves and a lateral groove.

[0047] The "average sipe density D" is calculated by dividing the total area in plan view of all sipes present in a block having two or more sipes by the total area in plan view of all blocks having two or more sipes. Average sipe density D = Total area in plan view of all sipes in blocks with 2 or more sipes / Total area in plan view of all blocks with 2 or more sipes

[0048] The "sipe density in one block" is calculated by the following formula. (Sipe density in one block) = (total area of ​​sipes in a plan view of one block) / (total area of ​​blocks in a plan view of one block)

[0049] In this specification, the term "tie bar" refers to a raised portion formed below a sipe, and is indicated by reference numeral 6 in FIG.

[0050] "Styrene content" is measured by pyrolysis gas chromatography and NMR measurement ( 1 H-NMR and 13 The amount of components such as "styrene content" is calculated by C-NMR. Unlike physical property values ​​such as complex modulus (E*), the amount of components such as "styrene content" has a true value that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible. 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.

[0051] "Vinyl content (amount of 1,2-bonded butadiene units)" can be measured by pyrolysis gas chromatography or NMR measurement ( 1 H-NMR and 13 It is calculated using C-NMR. As with the "styrene content," there is a true value for the "vinyl content" that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0052] "Cis content (cis-1,4-bonded butadiene unit amount)" is measured by infrared absorption spectroscopy or NMR measurement ( 1 H-NMR and 13 This is a value measured by C-NMR and is applied to rubber components that have repeating units derived from butadiene, such as BR. As with the "styrene content," there is a true value for the "cis content" that is independent of the measurement method, so it is preferable to use a measurement method with as high accuracy as possible.

[0053] 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 SuperMultipore HZ-M column manufactured by Tosoh Corporation). This applies to, for example, rubber components, plasticizers, and the like.

[0054] The "nitrogen adsorption specific surface area (N2SA) of carbon black" is measured in accordance with JIS K 6217-2:2017.

[0055] The "nitrogen adsorption specific surface area (N2SA) of silica" is measured by the BET method in accordance with ASTM D3037-93.

[0056] 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}).

[0057] "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.

[0058] The "plasticizer content" also includes the amount of plasticizer in the rubber component extended by the plasticizer.

[0059] 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.

[0060] The following describes the embodiments in more detail. However, the following description is merely an example for explaining the present invention, and the present invention is not limited thereto. Furthermore, although the following description uses drawings as appropriate, the drawings are merely examples.

[0061] [tire] A tire according to one embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and the tire of the present invention is not limited to the following embodiment.

[0062] FIG. 1 is a development view of the tire contact patch of a tire according to one embodiment of the present invention. The tread portion according to this embodiment has two or more circumferential grooves and two or more lateral grooves, and has one or more blocks defined by at least the circumferential grooves and the lateral grooves. In FIG. 1, the tread portion has four circumferential grooves 2. In FIG. 1, three of the four circumferential grooves 2 extend linearly in parallel to the tire circumferential direction. Meanwhile, the second circumferential groove from the left in the drawing extends in a zigzag pattern. However, the tread portion according to this embodiment is not limited to this form.

[0063] At least one block out of one or more blocks has two or more sipes. In FIG. 1 , all blocks 4 in the tread portion have sipes 5, satisfying the requirement of having two or more sipes. The sipes 5 are zigzag in their lengthwise direction and also in their depthwise direction. The tire according to this embodiment is not limited to this configuration, and it is sufficient if at least one block has two or more sipes. However, from the viewpoint of the effects of the present invention, it is preferable that the number of blocks having two or more sipes is large, and it is preferable that 90% or more of all blocks have two or more sipes, and it is even more preferable that all blocks have two or more sipes.

[0064] In the tread portion according to this embodiment, the average value D of the sipe density in all blocks having two or more sipes is greater than 0.005, preferably 0.006 or more, and more preferably 0.007 or more. The average value D of the sipe density in all blocks having sipes is preferably 0.015 or less, more preferably 0.010 or less, and even more preferably 0.009 or less.

[0065] In the tread portion according to this embodiment, the form of the sipes is not particularly limited, but it is preferable that they are inclined with respect to the tire axial direction. Also, it is preferable that the sipes extend in a zigzag pattern in their length direction. When the sipes extend in a zigzag pattern in their length direction, the direction of the inclination of the sipes is determined by the direction of the inclination of an imaginary line connecting both ends of the sipe.

[0066] The opening width of the sipe on the tread surface is preferably 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more. The opening width of the sipe on the tread surface is preferably 1.5 mm or less, more preferably 1.0 mm or less, and even more preferably 0.8 mm or less.

[0067] Fig. 2 shows a cross-sectional view of one sipe 5 of Fig. 1 taken along line AA. This cross-sectional view of line AA is a cross-sectional view along the groove of the sipe 5. In Fig. 2, the two-dot chain lines are imaginary lines indicating that the sipe is zigzag in its length direction and in its depth direction.

[0068] Furthermore, the sipes 5 preferably include tie bars 6 that protrude from the bottoms of the sipes 5 radially outward in the tire direction. The tie bars 6 refer to raised bottom portions. The height of the tie bars 6 in the tire radial direction is preferably 40 to 70% of the depth of the deepest part of the sipe. When the sipes 5 extend in a zigzag pattern in the depth direction, the width of the tie bars 6 in the tire axial direction is preferably 10 to 40% of the total length of the sipe.

[0069] The tread portion according to the present embodiment is made of a rubber composition containing a rubber component, a filler, and a plasticizer, and the total styrene content S in the rubber component is less than 10% by mass. The total styrene content S in the rubber component is preferably 9.8% by mass or less, more preferably 9.5% by mass or less, and even more preferably 9.2% by mass or less. The total styrene content S in the rubber component is preferably 5.0% by mass or more, more preferably 6.0% by mass or more, even more preferably 7.0% by mass or more, and particularly preferably 7.5% by mass or more.

[0070] The total styrene content S in the rubber component can be adjusted appropriately by changing the types and blending amounts of the rubber components, resins, etc., which will be described later. For example, the total styrene content S can be increased by increasing the content of styrene-butadiene rubber with a high styrene content.

[0071] When the total styrene content in the rubber component is S (mass%), the average sipe density in all blocks having two or more sipes is D, and the total content of plasticizer per 100 parts by mass of the rubber component is P (parts by mass), P x D x S is greater than 2.00, preferably greater than 2.20, more preferably greater than 2.30, and even more preferably greater than 2.50. There is no upper limit to P x D x S, but it is preferably less than 4.50, more preferably less than 4.00, and even more preferably less than 3.80. The total content P (parts by mass) of plasticizer per 100 parts by mass of the rubber component will be described later.

[0072] P×D×S is preferably greater than 0.020, more preferably greater than 0.025, and even more preferably greater than 0.028. There is no particular upper limit to P×D×S, but it is preferably less than 0.060, more preferably less than 0.050, and even more preferably less than 0.048.

[0073] P / S is preferably greater than 4.00, more preferably greater than 4.30, and even more preferably greater than 4.50. There is no particular upper limit to P / S, but it is preferably less than 9.00, more preferably less than 8.50, and even more preferably less than 8.00.

[0074] [Rubber composition] The rubber composition constituting the tread portion according to the present embodiment (hereinafter referred to as the rubber composition according to the present embodiment) will be described. The rubber composition according to the present embodiment is composed of a rubber composition containing a rubber component, a filler, and a plasticizer.

[0075] <Rubber component> The rubber composition according to the present embodiment contains a diene rubber as a rubber component. The diene rubber includes a styrene-butadiene rubber (SBR) and further includes an isoprene (IR) rubber and / or a butadiene rubber (BR). The rubber component may be a rubber component consisting solely of the diene rubber.

[0076] (Isoprene rubber) Examples of isoprene-based rubbers that can be used include those commonly used in the tire industry, such as isoprene rubber (IR) and natural rubber. Natural rubber includes unmodified natural rubber (NR) as well as modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), highly purified natural rubber, and grafted natural rubber. IR-based rubbers may be used alone or in combination of two or more.

[0077] The NR is not particularly limited, and those commonly used in the tire industry can be used, such as SIR20, RSS#3, and TSR20.

[0078] The content of the IR rubber in the rubber component is preferably 1% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 40% by mass or more. From the viewpoint of blending other rubber components, the content of the IR rubber is preferably 80% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0079] (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), or modified BR (high-cis modified BR, low-cis modified BR). One type of BR may be used alone, or two or more types may be used in combination.

[0080] 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 90 mol%, more preferably more than 95 mol%, and even more preferably 96 mol% or more. The cis content of BR is measured by the above-mentioned measurement method.

[0081] 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.

[0082] The SPB-containing BR is not simply 1,2-syndiotactic polybutadiene crystals dispersed in the BR, but is 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.

[0083] Examples of modified BR include BR modified with functional groups similar to those described above for SBR, and also preferably used are modified butadiene rubbers (modified BRs) whose terminals and / or main chains are modified with functional groups containing at least one element selected from the group consisting of silicon, nitrogen, and oxygen.

[0084] 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.

[0085] From the viewpoint of abrasion resistance, the weight-average molecular weight (Mw) of BR is preferably more than 300,000, more preferably more than 350,000, and even more preferably more than 400,000. From the viewpoint of crosslink uniformity, etc., it is preferably less than 2,000,000, more preferably less than 1,000,000, and even more preferably less than 500,000. Mw can be determined by the above-mentioned method.

[0086] The content of BR in the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The content of BR in the rubber component is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0087] The total content of the isoprene-based rubber and the butadiene-based rubber in the rubber component is more than 50% by mass, preferably 52% by mass or more, and more preferably 55% by mass or more. From the viewpoint of compounding SBR, the total content is less than 95% by mass, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less.

[0088] (SBR) The SBR is not particularly limited, and examples thereof include solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), and modified SBRs thereof (modified S-SBR, modified E-SBR). Modified SBRs include SBRs whose ends and / or main chains are modified, and modified SBRs coupled with tin, silicon compounds, etc. (condensates, those having a branched structure, etc.). Furthermore, hydrogenated products of these SBRs (hydrogenated SBRs) can also be used. One type of SBR may be used alone, or two or more types may be used in combination.

[0089] As the SBR, either oil-extended or non-oil-extended SBR can be used. In this specification, commercially available SBRs from JSR Corporation, Sumitomo Chemical Co., Ltd., UBE Corporation, Asahi Kasei Corporation, ZS Elastomers Co., Ltd., ARLANXEO, etc. can be used.

[0090] From the viewpoint of the effects of the present invention, the styrene content of SBR is preferably more than 10% by mass, more preferably more than 15% by mass, and even more preferably more than 19% by mass. On the other hand, the styrene content of SBR is preferably less than 55% by mass, more preferably less than 50% by mass, and even more preferably less than 45% by mass. The styrene content of SBR is measured by the above-mentioned measurement method.

[0091] The vinyl content of SBR is preferably more than 10 mol%, more preferably more than 15 mol%, and even more preferably more than 20 mol%. The vinyl content of SBR is preferably less than 70 mol%, more preferably less than 65 mol%, and even more preferably less than 60 mol%. The vinyl content of SBR is measured by the above-mentioned measurement method.

[0092] From the viewpoint of wet grip performance, the glass transition point (Tg) of SBR is preferably -80°C or higher, more preferably -70°C or higher, and even more preferably -65°C or higher. From the viewpoint of fuel economy, the Tg of SBR is preferably -40°C or lower, more preferably -45°C or lower, even more preferably -50°C or lower, and even more preferably -55°C or lower. The Tg of SBR is determined in accordance with JIS K 6229 by removing the extender oil with acetone and then subjecting the pure SBR content to differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0093] The weight average molecular weight (Mw) of SBR is preferably more than 200,000, more preferably more than 300,000, even more preferably more than 400,000, and particularly preferably more than 500,000. From the viewpoint of crosslink uniformity, Mw is preferably less than 2,000,000, more preferably less than 1,500,000, and even more preferably less than 1,000,000. The Mw of SBR is measured by the above-mentioned measurement method.

[0094] From the viewpoint of the effects of the present invention, the content of SBR in the rubber component is more than 5% by mass, preferably more than 10% by mass, more preferably more than 20% by mass, and even more preferably more than 30% by mass, and less than 50% by mass, preferably less than 48% by mass, and even more preferably less than 45% by mass.

[0095] (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 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. The other rubber components may be used alone or in combination of two or more. In addition to the above rubber components, known thermoplastic elastomers may or may not be contained.

[0096] (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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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 14This 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.

[0102] 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 elements.

[0103] on the other hand, 14 C 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.

[0104] 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 / 12C) 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.

[0105] 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%.

[0106] 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.

[0107] [Filler] The rubber composition according to the present embodiment contains a filler containing silica. The filler preferably further contains carbon black. Alternatively, the filler may be composed only of carbon black and silica.

[0108] <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 a biomass material such as rice husk), or silica recycled from a product containing silica. Silica made from a biomass material is called biomass silica. The silica according to this embodiment preferably contains biomass silica. One type of silica may be used alone, or two or more types may be used in combination.

[0109] Biomass silica 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 a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0110] 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.

[0111] When silica crystallizes, it does not dissolve in water, and its component, silicic acid, cannot be used. 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 and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222). Rice husk silica commercially available from Wilmar, Inc., can be used.

[0112] The nitrogen adsorption specific surface area (N2SA) of silica is 110m from the viewpoint of reinforcement. 2 / g or more is preferable, and 125m 2 / g is more preferable, and 150m2 / g or more is more preferable, and 170m 2 From the viewpoint of heat buildup and processability, it is particularly preferable that the tensile strength is more than 220m / g. 2 / g is preferable, and 200m 2 / g is more preferable, and 180m 2 / g or less is more preferable. The N2SA of silica is measured by the above-mentioned measurement method.

[0113] The average primary particle size of silica is preferably greater than 12 nm, more preferably greater than 14 nm, and even more preferably greater than 16 nm. The average primary particle size is preferably less than 40 nm, more preferably less than 30 nm, and even more preferably less than 20 nm. The average primary particle size of silica is measured by the above-mentioned measurement method.

[0114] The amount of silica per 100 parts by mass of the rubber component is more than 50 parts by mass, preferably more than 60 parts by mass, more preferably more than 70 parts by mass, and even more preferably more than 80 parts by mass, and is preferably less than 150 parts by mass, more preferably less than 120 parts by mass, and even more preferably less than 110 parts by mass.

[0115] <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 singly or in combination.

[0116] The content of the silane coupling agent is preferably more than 3 parts by mass, more preferably more than 5 parts by mass, and even more preferably more than 8 parts by mass relative to 100 parts by mass of silica from the viewpoint of improving the dispersibility of silica, and from the viewpoint of cost and processability, it is preferably less than 40 parts by mass, more preferably less than 30 parts by mass, and even more preferably less than 20 parts by mass.

[0117] The content of the silane coupling agent per 100 parts by mass of the rubber component is preferably more than 5 parts by mass, more preferably more than 7 parts by mass, and even more preferably more than 8 parts by mass from the viewpoint of improving the dispersibility of silica, and is preferably less than 20 parts by mass, more preferably less than 15 parts by mass from the viewpoint of preventing a decrease in abrasion resistance.

[0118] <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 biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace, 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. The filler preferably contains recycled carbon black. Carbon black may be used alone or in combination.

[0119] 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.

[0120] 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.

[0121] 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).

[0122] Recycled carbon black may lack functional groups on its surface, or may be treated to include functional groups on its surface. 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 from 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 from 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.

[0123] As the recycled carbon black, commercially available products from Strable Green Carbon, LD Carbon, etc. can be used.

[0124] The nitrogen adsorption specific surface area (N2SA) of carbon black is 80m from the viewpoint of reinforcement. 2 / g or more is preferable, and 90m 2 / g is more preferable, and 100m 2 / g or more is more preferable, and 110m 2 From the viewpoint of heat buildup and processability, it is particularly preferable that the tensile strength is more than 200 m / g. 2 / g is preferable, and 180m 2 / g is more preferable, and 150m 2 The N2SA of carbon black is measured by the above-mentioned measurement method.

[0125] The average primary particle size of carbon black is preferably greater than 15 nm, more preferably greater than 18 nm, and even more preferably greater than 20 nm. The average primary particle size is preferably less than 60 nm, more preferably less than 50 nm, and even more preferably less than 40 nm. The average primary particle size of carbon black is measured by the above-mentioned measurement method.

[0126] The amount of carbon black 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. The amount of carbon black per 100 parts by mass of the rubber component is preferably less than 50 parts by mass, more preferably less than 40 parts by mass, and even more preferably less than 30 parts by mass.

[0127] <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, magnesium sulfate, vulcanized rubber particles, aluminum hydroxide, calcium carbonate, alumina, clay, talc, and other fillers that have been commonly used in the tire industry. The rubber composition according to this embodiment preferably contains vulcanized rubber particles.

[0128] (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.

[0129] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0130] As commercially available vulcanized rubber, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., etc. can be used.

[0131] <Plasticizer> The rubber composition according to the present embodiment contains a plasticizer. A plasticizer is a material that imparts plasticity to a rubber component and encompasses both liquid and solid plasticizers at 25°C. Examples of plasticizers include resins, 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.

[0132] (resin component) In this embodiment, the plasticizer contains a C5 resin and / or a C9 resin. The rubber composition according to this embodiment may further contain other resin components. Resin components that can be used in this embodiment are not particularly limited, but include resins commonly used in the tire industry, such as adhesive resins such as aromatic vinyl resins, dicyclopentadiene resins, terpene resins, rosin resins, and phenolic resins. These resin components may be used alone or in combination of two or more.

[0133] <C9 resin> "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be a copolymer obtained by polymerizing a C9 fraction 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 petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumarone, indene, methylindene, and dicyclopentadiene.

[0134] <C5 resin> "C5 resin" refers to a resin obtained by polymerizing a C5 fraction, and may be a hydrogenated or modified C5 resin. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions having 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene.

[0135] <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. Examples of C5C9 petroleum resins that can be used include those commercially available from Tosoh Corporation, Luhua, and the like.

[0136] <Dicyclopentadiene resin> "Dicyclopentadiene resin" refers to a resin containing dicyclopentadiene (DCPD) as the monomer component with the largest content, and may be a hydrogenated or modified resin. Examples of dicyclopentadiene resins include DCPD / C9 resins obtained by copolymerizing dicyclopentadiene with the C9 fraction, with DCPD / C9 resins being preferred. Examples of DCPD resins that can be used include those commercially available from ExxonMobil Corporation, ENEOS Corporation, Nippon Zeon Co., Ltd., Maruzen Petrochemical Co., Ltd., and the like.

[0137] <Aromatic vinyl resin> The term "aromatic vinyl resin" refers to a resin containing an aromatic vinyl compound such as styrene, α-methylstyrene, vinyltoluene, or p-chlorostyrene 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, commercially available products from Kraton, Eastman Chemical, Mitsui Chemicals, Inc., etc., can be used.

[0138] <Cumarone resin> Coumarone resins refer to resins containing coumarone as a monomer component, and may be hydrogenated or modified. Examples of coumarone resins include coumarone-indene resins, which contain coumarone and indene as monomer components, and coumarone-indene-styrene resins, which contain coumarone, indene, and styrene as monomer components.

[0139] <Indene-based resin> Indene resins are resins containing indene as a monomer component, and may be hydrogenated or modified. Examples of coumarone resins include coumarone-indene resins, which contain coumarone and indene as monomer components, and coumarone-indene-styrene resins, which contain coumarone, indene, and styrene as monomer components.

[0140] <Terpene resin> Terpene resins refer to resins containing terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as the most abundant 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 styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds that serve as monomer components for terpene phenolic resins include phenol, bisphenol A, cresol, and xylenol.

[0141] <Rosin-based resin> The rosin-based resin refers to a resin containing a rosin acid compound such as abietic acid, neoabietic acid, palustric acid, or isopimaric acid, and may be a hydrogenated or modified version of such a resin. The rosin-based resin is not particularly limited, but examples thereof include natural rosin resin and rosin-modified resins obtained by modifying rosin by hydrogenation, disproportionation, dimerization, esterification, or the like.

[0142] <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 largest content. The phenolic resin is not particularly limited, but examples thereof include phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, oil-modified phenol formaldehyde resin, and terpene phenol resin.

[0143] ≪Softening point≫ From the viewpoint of grip performance, the softening point of the resin component is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 70° C. or higher. From the viewpoint of processability and improving the dispersibility of the rubber component and the filler, the softening point is preferably 150° C. or lower, more preferably 140° C. or lower, and even more preferably 130° C. or lower. The softening point of the resin component is measured by the above-mentioned measurement method.

[0144] ≪Content≫ The amount of the resin component per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 12 parts by mass or more. On the other hand, from the viewpoint of suppressing heat buildup, the amount is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0145] (Plasticizers other than resin components) The plasticizers other than the resin component, such as oil, liquid rubber, and ester-based plasticizers, will now be described.

[0146] (oil) Examples of oils include mineral oil, vegetable 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.

[0147] 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, oils with a low content of polycyclic aromatic compounds (PCA) can also be used as an environmentally friendly measure. Examples of low PCA oils include MES, TDAE, and heavy naphthenic oil. Mineral oils may be used singly or in combination.

[0148] The plasticizer preferably contains a vegetable oil. 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. Other examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above oils, interesterified oils obtained by interesterifying the above oils, hardened oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidatively polymerized oils obtained by oxidizing the above oils, and waste edible oils recovered from edible oils. The vegetable oil may be liquid or solid at 25°C. One vegetable oil may be used alone, or two or more may be used in combination.

[0149] 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.

[0150] 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 1 When 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] Examples of animal oils include fish oil, beef tallow, whale oil, and oleyl alcohol derived from these.

[0155] When oil is contained, the content 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 20 parts by mass or more, and particularly preferably 30 parts by mass or more. The content of oil is preferably 80 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

[0156] (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.

[0157] (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.

[0158] In view of the effects of the present invention, the content P of the plasticizer per 100 parts by mass of the rubber component is more than 40 parts by mass, preferably more than 42 parts by mass, and more preferably more than 45 parts by mass, while P is preferably less than 100 parts by mass, more preferably less than 80 parts by mass, still more preferably less than 70 parts by mass, and particularly preferably less than 65 parts by mass.

[0159] The oil content in the plasticizer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and particularly preferably 70% by mass or more, and is preferably 90% by mass or less, preferably 85% by mass or less, and more preferably 80% by mass or less.

[0160] [Other compounding agents] In addition to the rubber component, filler, and plasticizer, the rubber composition according to the present embodiment may contain compounding agents that are generally used in the tire industry, such as processing aids, wax, stearic acid, zinc oxide, antioxidants, vulcanizing agents, and vulcanization accelerators, as appropriate.

[0161] (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. One type of processing aid may be used alone, or two or more types may be used in combination. Examples of processing aids that can be used include those commercially available from Schill + Seilacher, Performance Additives, etc.

[0162] When a processing aid is contained, the content thereof per 100 parts by mass of the rubber component is preferably more than 0.5 parts by mass, more preferably more than 1 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 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance and breaking strength.

[0163] (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.

[0164] 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.

[0165] (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 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of vulcanization rate.

[0166] (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 8.0 parts by mass, and even more preferably less than 5.0 parts by mass from the viewpoint of abrasion resistance.

[0167] (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), and N,N'-ditolyl-p-phenylenediamine. p-phenylenediamine-based antioxidants such as diphenyl ether diphenyl ether (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.

[0168] When an antioxidant is contained, the content per 100 parts by mass of the rubber component is preferably more than 1.0 part by mass, more preferably more than 1.5 parts by mass, and even more preferably more than 2.0 parts by mass from the viewpoint of ozone crack resistance of the rubber, and is preferably less than 7.0 parts by mass, more preferably less than 6.0 parts by mass, and even more preferably less than 5.5 parts by mass from the viewpoint of abrasion resistance and wet grip performance.

[0169] (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.

[0170] When sulfur 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 0.8 parts by mass, and even more preferably more than 1.0 part by mass, from the viewpoint of ensuring a sufficient vulcanization reaction. Furthermore, from the viewpoint of preventing deterioration, the content is preferably less than 10 parts by mass, more preferably less than 8 parts by mass, even more preferably less than 5 parts by mass, and particularly preferably less than 4 parts by mass. 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.

[0171] 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.

[0172] (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. The vulcanization accelerators may be used alone or in combination of two or more. Among these, 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.

[0173] Examples of sulfenamide vulcanization accelerators include N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS).

[0174] 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.

[0175] 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.

[0176] Examples of thiuram vulcanization accelerators include tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide (TMTM), dipentamethylene thiuram disulfide, and dipentamethylene thiuram tetrasulfide.

[0177] Examples of the thiourea vulcanization accelerator include thiourea compounds such as thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea and diorthotolylthiourea, N,N'-diphenylthiourea, trimethylthiourea and N,N'-diethylthiourea.

[0178] Examples of dithiocarbamate vulcanization accelerators include piperidinium pentamethylenedithiocarbamate (PPDC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), zinc dibutyldithiocarbamate (ZnBDC), zinc dibenzyldithiocarbamate (ZDBzC), zinc N-ethyl-N-phenyldithiocarbamate (ZnEPDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), sodium dibutyldithiocarbamate (NaBDC), copper dimethyldithiocarbamate (CuMDC), iron dimethyldithiocarbamate (FeMDC), and tellurium diethyldithiocarbamate (TeEDC).

[0179] When a vulcanization accelerator is contained, the content thereof per 100 parts by mass of the rubber component is preferably more than 2 parts by mass, more preferably more than 3 parts by mass, and even more preferably more than 4 parts by mass. The content of the vulcanization accelerator per 100 parts by mass of the rubber component is preferably less than 20 parts by mass, more preferably less than 10 parts by mass, and even more preferably less than 6 parts by mass.

[0180] In this specification, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, 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.

[0181] [Manufacturing] The rubber composition can be produced by a known method, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or an internal kneader (such as a Banbury mixer or kneader).

[0182] 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 may be divided into multiple processes as desired. When the base kneading process is divided, the method may be (1) a method in which some of the compounding ingredients and additives are pre-mixed to form a masterbatch, and then the remaining compounding ingredients and additives are added to the resulting masterbatch and kneaded, or (2) a method in which all of the compounding ingredients and additives to be kneaded in the base kneading process are kneaded at once, and then the kneaded product is remilled one or more times. In the above method (1), the number of masterbatches is not limited and may be two or more. Furthermore, when the number of masterbatches is two or more, all of the compounding ingredients and additives used in the base kneading process may be allocated to one of the masterbatches.

[0183] 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 in the final kneading step, kneading for 1 to 5 minutes at 70 to 110°C.

[0184] A tire having a tread portion made of a rubber composition can be manufactured by a conventional method. That is, the tire can be manufactured by extruding an unvulcanized rubber composition prepared by blending the above-mentioned components with a rubber component as needed to form a tread portion, laminating and molding the unvulcanized tire components thus obtained together with other tire components in a tire building machine by a conventional method to form an unvulcanized tire, and then heating and pressurizing the unvulcanized tire thus obtained in a vulcanizer. The vulcanization conditions are not particularly limited, and examples include a method of vulcanizing at 150 to 200°C for 10 to 30 minutes.

[0185] [Application] The tire according to the present embodiment can be used for any purpose, regardless of whether it is a pneumatic tire or a non-pneumatic tire, but is preferably a pneumatic tire. It can also 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. The tire according to the present embodiment can also be used as an all-season tire, a summer tire, a studless tire, or the like, with studless tires being particularly preferred. [Example]

[0186] Examples (working examples) that are considered preferable for carrying out the present invention are shown below, but the scope of the present invention is not limited to these working examples. Rubber compositions and tires obtained according to the tables were examined using the various chemicals shown below, and the results calculated based on the evaluation methods below are shown in the tables.

[0187] <Various chemicals> The chemicals used in the examples and comparative examples are summarized below. IR rubber: TSR20 (natural rubber) SBR1: SBR produced by Production Example 1 below (S-SBR, Tg: -60°C, styrene content: 20% by mass, vinyl content: 20% by mole, Mw: 700,000, non-oil extended) SBR2: HPR850 manufactured by JSR Corporation (S-SBR, styrene content: 27.5% by mass, Tg: -24°C, Mw: 200,000, non-oil extended) BR: BR730 (cis content: 95 mol%) manufactured by ENEOS Materials Corporation Carbon black 1: Show Black N220 (N2SA: 115 ml) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle diameter: 22nm) Carbon black 2: SS550 manufactured by Streble Green Carbon (recycled carbon black obtained by the pyrolysis process of tires) Silica 1: Ultrasil VN3 (N2SA: 175 ml) manufactured by Evonik Industries 2 / g, average primary particle diameter: 18nm) Silica 2: Wilmar K185 (amorphous silica purified from rice husks) Magnesium sulfate: MN-00 manufactured by Mai Chemical Industry Co., Ltd., obtained by sieving through a 500 mesh sieve (median particle size: 10 μm) Vulcanized rubber particles: Powdered rubber powder W2-A (30 mesh vulcanized rubber powder) manufactured by Asahi Reclaimed Rubber Co., Ltd. Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Industries Oil 1: Diana Process NH-70S (aromatic process oil) manufactured by Idemitsu Kosan Co., Ltd. Oil 2: Industrial soybean oil manufactured by Kaneda Co., Ltd. Resin component 1: Kraton Sylvares SA85 (a copolymer of α-methylstyrene and styrene (aromatic vinyl resin), softening point: 85°C) Resin component 2: PR803 (hydrogenated DCPD / C9 resin (C9 resin), softening point: 103°C) manufactured by ENEOS Material Co., Ltd. Wax: Ozoace wax (paraffin wax) manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: Nocrac 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Antioxidant 2: Nocrac RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Processing aid: Aflux 16 manufactured by Rhein Chemie (a mixture of fatty acid calcium salt and fatty acid amide ester, calcium content: 6.2%) Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Camellia stearic acid beads manufactured by NOF Corporation Sulfur: HK-200-5 (powdered sulfur containing 5% oil) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela M (2-mercaptobenzothiazole) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 3: Noccela DPG (1,3-diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0188] (Production Example 1: Production of SBR1) Cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene are charged into a nitrogen-purged autoclave reactor. The ratio of styrene to 1,3-butadiene is adjusted so that the styrene content is 20% by mass. After adjusting the temperature of the reactor contents to 20°C, n-butyllithium is added to initiate polymerization. Polymerization occurs under adiabatic conditions, reaching a maximum temperature of 80°C. After confirming the formation of a polymer with a Mw of 700,000 by GPC, the polymerization solution is poured into 4 L of ethanol and the precipitate is recovered. The resulting precipitate is blown dry and then vacuum dried at 80°C / 10 Pa or less until the loss on drying is 0.1%, yielding SBR1.

[0189] Examples and Comparative Examples According to the compounding recipes shown in Table 1 or Table 2, a 1.7 L closed-type Banbury mixer was used to knead all the chemicals except sulfur and the vulcanization accelerator at a discharge temperature of 160°C for 4 minutes to obtain a kneaded mixture. Next, using an open roll, sulfur and the vulcanization accelerator were added to the obtained kneaded mixture, and the mixture was kneaded for 4 minutes until the temperature reached 105°C to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was molded to fit the shape of the tread portion, and then bonded together with other tire components to produce an unvulcanized tire. The tire was then vulcanized at 170°C to obtain each test tire (size: 195 / 65R15, rim: 15x6.0JJ, internal pressure: 230 kPa).

[0190] <Ice performance> Each test tire was fitted to all wheels of a vehicle (a domestic FF 1500cc) and the braking distance from the point where the brakes were applied on an icy road was measured. 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. The higher the index, the better the performance on ice. (Ice performance index) = (braking distance of control tire) / (braking distance of each test tire)

[0191] <Wet grip performance> Each test tire was fitted to all wheels of a vehicle (domestic FF 1500cc), and the braking distance from the point where the brakes were applied on a wet road surface was measured. 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. The higher the index, the better the wet grip performance. (Wet grip performance index) = (braking distance of control tire) / (braking distance of each test tire)

[0192] The sum of the ice performance index and the wet grip performance index is the overall performance index.

[0193] [Table 1]

[0194] [Table 2]

[0195] <Embodiment> Examples of embodiments of the present invention are given below. [1] A tire having a tread portion, the tread portion is composed of a rubber composition containing a rubber component, a filler containing silica, and a plasticizer, The rubber component includes a styrene-butadiene rubber, The content of the styrene-butadiene rubber in the rubber component is more than 5% by mass and less than 50% by mass, the rubber component contains an isoprene-based rubber and / or a butadiene rubber, the total content of the isoprene-based rubber and the butadiene rubber in the rubber component is more than 50% by mass, The total styrene content S (mass%) in the rubber component is less than 10, The content of the silica per 100 parts by mass of the rubber component is more than 50 parts by mass, the plasticizer contains a C5 resin and / or a C9 resin, The total content P (parts by mass) of the plasticizer relative to 100 parts by mass of the rubber component is more than 40, the tread portion has two or more circumferential grooves, two or more lateral grooves, and one or more blocks defined by at least the circumferential groove and the lateral groove, At least one of the blocks has two or more sipes, The average value D of the sipe densities in all blocks having two or more sipes is greater than 0.005, A tire, wherein S, P, and D satisfy the following formulas: (1) P × D × S > 2.00 [2] The tire according to [1] above, wherein the plasticizer further contains vegetable oil. [3] The tire according to [1] or [2] above, wherein the silica includes biomass silica. [4] The tire according to any one of the above [1] to [3], wherein the filler contains recycled carbon black. [5] The tire according to any one of the above [1] to [4], wherein the rubber composition contains vulcanized rubber particles. [6] The tire according to any one of the above [1] to [5], wherein at least one of the sipes extends in a zigzag pattern in the depth direction of the sipe. [7] The tire according to any one of the above [1] to [6], wherein the sipe includes a tie bar protruding from the bottom thereof outward in the tire radial direction. [8] The tire according to the above [7], wherein the height of the tie bar in the tire radial direction is 40 to 70% of the depth of the deepest part of the sipe. [9] The sipe extends in a zigzag pattern in its length direction, The tire according to [7] or [8], wherein the width of the tie bar in the tire axial direction is 10 to 40% of the total length of the sipe.

[10] The tire according to any one of the above [1] to [9], wherein S, P, and D satisfy the following formulas: (2) P × D / S > 0.020

[11] The tire according to any one of the above [1] to

[10] , wherein the S and the P satisfy the following formula: (3) P / S>4.00

[12] The tire according to any one of the above [1] to

[11] , wherein the content of oil in the plasticizer is 60% by mass or more.

[13] The tire according to any one of [1] to

[12] above, which is a studless tire. [Explanation of symbols]

[0196] 1 Tire contact surface 2 Circumferential groove 3 Yokomizo 4 blocks 5 sipes 6 tie bars TW tread width

Claims

1. A tire having a tread portion, the tread portion is composed of a rubber composition containing a rubber component, a filler containing silica, and a plasticizer, The rubber component includes a styrene-butadiene rubber, the content of the styrene-butadiene rubber in the rubber component is more than 5% by mass and less than 50% by mass, the rubber component contains an isoprene-based rubber and / or a butadiene rubber, the total content of the isoprene-based rubber and the butadiene rubber in the rubber component is more than 50% by mass, The total styrene amount S (mass%) in the rubber component is less than 10, The content of the silica per 100 parts by mass of the rubber component is more than 50 parts by mass, the plasticizer contains a C5 resin and / or a C9 resin, a total content P (parts by mass) of the plasticizer relative to 100 parts by mass of the rubber component is more than 40, the tread portion has two or more circumferential grooves, two or more lateral grooves, and one or more blocks defined by at least the circumferential groove and the lateral groove, At least one of the blocks has two or more sipes, the average value D of sipe densities in all blocks having two or more sipes is greater than 0.005; A tire, wherein S, P, and D satisfy the following formulas: (1) P x D x S > 2.00

2. The tire of claim 1 , wherein the plasticizer further comprises vegetable oil.

3. The tire of claim 1 or 2, wherein the silica comprises biomass silica.

4. 3. The tire of claim 1 or 2, wherein the filler comprises recycled carbon black.

5. The tire of claim 1 or 2, wherein the rubber composition comprises vulcanized rubber particles.

6. 3. The tire according to claim 1, wherein at least one of the sipes extends in a zigzag pattern in the depth direction of the sipe.

7. 3. The tire of claim 1, wherein the sipe includes a tie bar extending radially outward from the bottom of the sipe.

8. The tire according to claim 7, wherein the height of the tie bar in the tire radial direction is 40 to 70% of the depth of the deepest part of the sipe.

9. The sipe extends in a zigzag pattern in its longitudinal direction, The tire according to claim 7, wherein the width of the tie bar in the tire axial direction is 10 to 40% of the total length of the sipe.

10. The tire according to claim 1 or 2, wherein S, P, and D satisfy the following formulas: (2) P×D / S>0.020

11. The tire according to claim 1 or 2, wherein S and P satisfy the following formula: (3) P / S>4.00

12. The tire according to claim 1 or 2, wherein the content of oil in the plasticizer is 60 mass % or more.

13. The tire according to claim 1 or 2, which is a studless tire.

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