Tire

Abstract

Provided is a tire that can achieve improved steering stability performance during high-speed travel. A tire characterized by being a tire having a tread composed of a rubber composition containing a rubber component and a filler, the rubber component containing an isoprene-based rubber and a styrene butadiene rubber, the content of the isoprene-based rubber in the rubber component being 40% by mass or greater, the glass transition temperature Tg of the styrene butadiene rubber being -60°C or lower, the filler containing silica, the rubber composition containing 130 parts by mass or greater of silica per 100 parts by mass of the rubber component, and when the thickness of the tread is set as T (mm) and the total content of the filler in the rubber composition per 100 parts by mass of the rubber component is set as F (parts by mass), T / F is less than 0.16.

Description

Technical Field

[0001] This invention relates to a tire. Background Technology

[0002] Patent document 1 describes a tire having a tread composed of a rubber composition containing isoprene-based rubber and silica, wherein the tanδ at 20°C and the tanδ at -20°C are within a specified range, which effectively improves low fuel consumption, wear resistance, handling stability at high speeds, and wet grip at high speeds. [Existing Technical Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2021-25006 Summary of the Invention [The problem the invention aims to solve]

[0004] When isoprene-based rubbers and styrene-butadiene rubbers are used together, silica tends to agglomerate in the styrene-butadiene rubber phase, making it difficult to disperse. Therefore, there is still room for improvement in the various properties of the tires.

[0005] On the other hand, with the continuous advancement of highway construction, long-distance high-speed driving is no longer unusual, thus placing higher demands on the handling stability performance of pneumatic tires at high speeds.

[0006] The purpose of this invention is to provide a tire with improved handling stability at high speeds. [Methods for solving the problem]

[0007] This invention relates to a tire, characterized in that, It is a tire with a tread. The tread is composed of a rubber composition containing rubber components and fillers. The rubber composition contains isoprene-based rubber and styrene-butadiene rubber. The content of isoprene-based rubber in the rubber component is 40% by mass or more. The glass transition temperature (Tg) of the styrene-butadiene rubber is below -60℃. The filler contains silicon dioxide. The rubber composition contains 130 or more parts by mass of silicon dioxide relative to 100 parts by mass of the rubber component. When the thickness of the tread is defined as T (mm) and the total content of filler in the rubber composition relative to 100 parts by mass of the above rubber components is defined as F (parts by mass), T / F is less than 0.16. [Invention Effects]

[0008] According to the present invention, a tire with improved handling stability at high speeds is provided. Attached Figure Description

[0009]

【 Figure 1 A partial cross-sectional view of a tire through the tire's rotation axis according to one embodiment of the present invention. [Explanation of Labels in the Attached Image] 1: Tread surface 2: Zhouxianggou 6: First floor 7: Second layer T: Tread thickness CL: Tire equator. Detailed Implementation

[0010] The following describes a tire according to an embodiment of the present invention. The tire according to this embodiment is characterized in that it is a tire having a tread, the tread being composed of a rubber composition containing rubber components and fillers. The rubber components contain isoprene rubber and styrene-butadiene rubber. The isoprene rubber content in the rubber components is 40% by mass or more, the glass transition temperature Tg of the styrene-butadiene rubber is -60°C or less, the filler contains silica, and the rubber composition contains 130 parts by mass or more of silica relative to 100 parts by mass of the rubber components. When the thickness of the tread is defined as T (mm) and the total content of the filler in the rubber composition relative to 100 parts by mass of the aforementioned rubber components is defined as F (parts by mass), the ratio T / F is less than 0.16.

[0011] While we do not wish to limit ourselves theoretically, the reasons for the improved handling stability at high speeds in this invention can be considered as follows.

[0012] For example, in the tire of the present invention, (1) by containing isoprene rubber and styrene-butadiene rubber, and the content of isoprene rubber in the above rubber components being 40% by mass or more, an isoprene rubber phase of a certain size or larger is formed in the rubber matrix. By generating an interface with the styrene-butadiene rubber phase, the road input (pressure) during driving can be mitigated, thus contributing to improved handling stability. In addition, (2) by making the glass transition temperature Tg of styrene-butadiene rubber below -60°C, the temperature dependence of the elastic modulus in the high-temperature range is reduced, thus contributing to improved handling stability at high speeds. (3) by containing 130 parts by mass or more of silica relative to 100 parts by mass of the rubber components, the effect of silica reinforcing the polymer chain is easily obtained, thus contributing to improved handling stability at high speeds. (4) by making the ratio of the total filler content to the tread thickness T / F less than 0.16, it contributes to improved handling stability at high speeds. It can be considered that, through the synergistic effect of (1) to (4) above, the particularly significant effect of improving the handling stability at high speeds can be achieved.

[0013] The rubber composition described above preferably contains 150 parts by mass of silica or more relative to 100 parts by mass of the rubber component.

[0014] This is because it can be assumed that the reinforcing polymer chain effect brought by silica is more easily obtained, thus improving the handling stability at high speeds.

[0015] The preferred CTAB specific surface area C of the aforementioned silica is 190 m². 2 / g or more.

[0016] It can be assumed that by making the specific surface area C of CTAB 190m² 2 With a g / g or higher, the number of bonding points between silica and polymer increases, and the network structure becomes more robust, thus further improving handling stability at high speeds.

[0017] The above-mentioned rubber composition preferably contains 50 or more parts by mass of resin component relative to 100 parts by mass of the above-mentioned rubber component.

[0018] It can be considered that by mixing more than 50 parts by weight of resin components, the rubber can be given adhesive force, and the road surface following ability can be improved. Therefore, in addition to obtaining the effects of the present invention, the grip performance is also improved.

[0019] The styrene content of the above-mentioned styrene-butadiene rubber is preferably 20% by mass or more.

[0020] It can be argued that the effect of mitigating road surface input during driving is further improved, and the handling stability at high speeds is further enhanced.

[0021] The acetone extraction amount AE (mass%) of the above rubber composition is preferably 25.0 or more.

[0022] The resin composition is preferably selected from at least one of C9 resins, dicyclopentadiene resins, and terpene resins.

[0023] It can be considered that by mixing the above-mentioned resin components, the rubber can be given adhesive force, and the following of the road surface can be improved. Therefore, the rubber's grip on the road surface is improved. Thus, in addition to the effects of the present invention, the grip performance is also improved.

[0024] The rubber composition described above preferably contains a mercapto-based silane coupling agent.

[0025] It can be argued that due to the high reactivity of mercapto-based silane coupling agents, the number of binding points between the polymer and silica increases, the reinforcing property is enhanced, thus improving rigidity and further improving handling stability.

[0026] The above-mentioned resin components preferably contain liquid resin.

[0027] The above-mentioned rubber composition preferably contains liquid rubber.

[0028] The above-mentioned rubber composition preferably contains vegetable oil.

[0029] When the acetone extraction amount of the above rubber composition is set as AE (mass%), it is preferable that F×AE is greater than 3500. It can be considered that by setting F×AE within the above range, the rigidity is increased due to the increased auxiliary effect of the filler on the polymer chain, and the heat generation is enhanced due to the friction between the fillers, thus improving the handling stability and wet grip performance.

[0030] When the acetone extraction amount of the above rubber composition is set as AE (mass%), it is preferable that T×AE is greater than 400. It can be considered that by setting T×AE within the above range, the rigidity is increased due to the increased reinforcing effect of the filler on the polymer chain, and the heat generation is enhanced due to the friction between the fillers, thus improving the handling stability and wet grip performance.

[0031] Let the CTAB specific surface area of ​​the above-mentioned silica be C(m²). 2 When T / C is less than 0.10, it is preferable that T / C is less than 0.10. It can be considered that by setting T / C within the above range, the reinforcing effect of silica on the polymer chain is increased, and the block rigidity is increased, thus improving the handling stability at high speeds.

[0032] The maximum load capacity of the above tires is set to W. L When the weight of the above tires is set as G (kg), G / W L Preferably, it is below 0.0170.

[0033] <Definition> "Standard condition" refers to a tire in a standard condition, assembled on a standard rim and filled with air at the standard internal pressure, under no load. Unless otherwise specified, tires in the standard condition should be used.

[0034] "Standard rim" refers to the rim specified for each tire within a standard system that includes the standards upon which the tire is based. Examples include the standard rim with applicable dimensions listed in the JATMA (Japan Automobile Tire Association) Yearbook, the "Measuring Rim" listed in the ETRTO (European Tyre and Rim Technical Organization) Standards Manual, and the "Design Rim" listed in the TRA (Tire and Rim Association, Inc.) Yearbook. These should be referenced in the order of JATMA, ETRTO, and TRA, and if applicable dimensions are available, their standards should be followed. Furthermore, for tires not specified in the aforementioned standards, it refers to the rim with the smallest width among the smallest diameter rims that can be assembled with the tire and maintain internal pressure (i.e., no air leakage between the rim and tire).

[0035] "Standard internal pressure" refers to the air pressure specified for each tire within a standard system that includes the standard upon which the tire is based. Examples include JATMA's "Maximum Air Pressure," ETRTO's "Inflation Pressure," and TRA's table "Tire Load Limits at Various Cold Inflation Pressures." Similar to the case of standard rims, it is referenced in the order of JATMA, ETRTO, and TRA. If an applicable size is available, its standard should be followed. Furthermore, for tires not specified in the aforementioned standards, it refers to the standard internal pressure (above 250 kPa) of other tire sizes (but must be tires specified in the standard) recorded using the aforementioned standard rims as the standard rim. If multiple standard internal pressures above 250 kPa are recorded, the minimum value is used.

[0036] "Regular load" refers to the maximum load specified for each tire within a standard system that includes the standard upon which the tire is based. Examples include JATMA's "Maximum Load Capacity," ETRTO's "Load Capacity," and TRA's "Tire Load Limits at Various Cold Inflation Pressures." Similar to the case of regular rims and regular tire pressures, this is referenced in the order of JATMA, ETRTO, and TRA. If applicable dimensions are available, their standards are followed. For tires not specified in the aforementioned standards, the maximum load capacity W will be calculated separately. L Set to normal load.

[0037] Maximum load capacity W L Calculated using the following formula. "V" represents the virtual volume of the tire (mm²). 3 "Dt" represents the tire's outer diameter (mm) under normal conditions, "Ht" represents the tire's cross-sectional height (mm) in the radial direction of the tire section obtained by cutting the tire along a plane containing the tire's axis of rotation, and "Wt" represents the tire's cross-sectional width (mm) under normal conditions. When the tire's rim diameter is set to R, Ht can be calculated by (Dt-R) / 2. If the tire sidewall has tread blocks or lettering, Wt is a value obtained without considering these. Furthermore, the maximum load capacity has the same meaning as the normal load described above.

[0038]

Number 1

[0039] "Tire weight G (kg)" refers to the weight of the tire alone, excluding the rim. On the other hand, if the tire contains components such as sponge, sealant, or sensor components, the weight includes these components.

[0040] "Tread" is a component that includes the part that forms the contact surface of the tire. In the case of a component that has a tire skeleton made of steel or textile material, such as a belt layer or belt reinforcement layer and a carcass layer, in a tire cross section based on a plane containing the tire's axis of rotation, it refers to a component located on the radially outer side of the tire.

[0041] "Tread thickness T (mm)" is the thickness of the entire tread measured along the normal to the tread contact surface on the tire equator in a section passing through the tire's axis of rotation. When the tire has circumferential grooves on the equator, it refers to the thickness measured along the normal to the tread contact surface at the center of the contact surface on both sides of the groove in the tire width direction, near the center of the contact surface in the tire width direction close to the tire equator surface.

[0042] A "groove" refers to a recessed area formed in the tread of a tire, where the opening width at the tread contact surface is 2.0 mm or more. Recesses with an opening width of less than 2.0 mm at the tread contact surface are called "sipes".

[0043] "Circumferential grooves" refer to grooves that extend around the circumference of the tire. Circumferential grooves can extend in a straight line, or in a wavy, sinusoidal, or sawtooth pattern.

[0044] "Rubber component of rubber composition" refers to the component that participates in cross-linking within the rubber composition, typically a component with a weight-average molecular weight (Mw) of 10,000 or higher.

[0045] "Plasticizer" refers to a material that imparts plasticity to rubber components; it is a component extracted from rubber compositions using acetone. Plasticizers include those that are liquid at 25°C and those that are solid at 25°C. However, they do not include waxes and stearic acid commonly used in the tire industry.

[0046] "Plasticizer content" also includes the amount of plasticizer contained in the incremental rubber component, which is pre-increased by plasticizers such as oil, resin components, and liquid rubber. Furthermore, the same applies to the content of oil, resin components, and liquid rubber; for example, when the incremental component is oil, the incremental oil is included in the oil content.

[0047] "Glass transition temperature (Tg) of rubber component" refers to the static glass transition temperature of each rubber component determined by differential scanning calorimetry (e.g., Q200 manufactured by TA Instruments Japan Co., Ltd.).

[0048] In this specification, "glass transition temperature Tg (°C) of styrene-butadiene rubber" refers to the glass transition temperature calculated for each styrene-butadiene rubber, even when the rubber composition contains two or more types of styrene-butadiene rubber.

[0049] "Acetone Extraction (AE) Amount" is calculated using the following formula, based on JIS K 6229, which involves immersing each vulcanized rubber test piece in acetone for 72 hours to extract soluble components, measuring the mass of each test piece before and after extraction, and then using this formula. Acetone extraction yield (mass%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0050] The styrene content was determined by pyrolysis gas chromatography or NMR. 1 H-NMR or 13 The styrene content and other component values ​​differ from physical properties such as the complex elastic modulus (E*), and thus have true values ​​independent of the measurement method. Therefore, it is preferable to use the most accurate measurement method possible. Furthermore, in this specification, "pyrolysis gas chromatography" refers to a method in which the sample is heated by a pyrolysis device, and the components contained in the gas phase generated by this heating are separated using a separation column, and the separated components are analyzed. Styrene content, for example, is applicable to rubber components such as SBR that have repeating units (styrene units) derived from styrene.

[0051] "Styrene content (mass%) of styrene-butadiene rubber" refers to the styrene content (mass%) of styrene-butadiene rubber (SBR). When the rubber composition contains only one type of SBR, it is the styrene content of that SBR. When the rubber composition contains multiple types of SBR, it is calculated by summing the product of the styrene content of each SBR and the amount (mass%) of that SBR when all SBRs are set to 100% by mass.

[0052] For example, when the rubber composition consists of 20% by mass of the first SBR (styrene content: 25% by mass), 30% by mass of the second SBR (styrene content: 27.5% by mass), and 50% by mass of BR, the styrene content of the styrene-butadiene rubber is 26.5% by mass (=(25×40 / 100)+(27.5×60 / 100)).

[0053] "Vinyl content (1,2-bonded butadiene unit weight)" was determined by pyrolysis gas chromatography or NMR. 1 H-NMR or 13 The content of vinyl groups is calculated using C-NMR. Similar to the content of styrene, the true value of vinyl groups exists independently of the determination method; therefore, it is preferable to use the most accurate determination method possible.

[0054] "cis content (cis-1,4-bonded butadiene unit mass)" is determined according to JIS K 6239-2:2017 by infrared absorption spectroscopy or NMR analysis. 1 H-NMR or 13The values ​​determined by C-NMR are applicable, for example, to rubber components such as BR that have repeating units derived from butadiene. Like the "styrene content," the "cis content" also has a true value that is independent of the measurement method; therefore, it is preferable to use the most accurate measurement method possible.

[0055] "Weight-average molecular weight (Mw)" is calculated based on the value determined by gel permeation chromatography (GPC) (e.g., Tosoh GPC-8000 series, detector: differential refractometer, column: Tosoh TSKgel (registered trademark) SuperMultipore HZ-M). It is applicable, for example, to SBR, BR, plasticizers, etc.

[0056] The nitrogen adsorption specific surface area (N2SA) of carbon black was determined according to JIS K 6217-2:2017.

[0057] "Nitrogen adsorption specific surface area (N2SA) of silica" is determined by the BET method according to ASTM D3037-93.

[0058] The "CTAB (hexadecyltrimethylammonium bromide) specific surface area C of silica" is determined according to ASTM D3765-92. When the rubber composition contains only one type of silica, the "CTAB specific surface area C" is the CTAB specific surface area of ​​that silica. When the rubber composition contains multiple types of silica, it is calculated by summing the products of the CTAB specific surface areas of each silica and the amount (by mass%) of that silica when all silica is considered to be 100% by mass.

[0059] The "average primary particle size" is calculated by taking photographs of the particles using a transmission or scanning electron microscope and then taking the arithmetic mean of the particle sizes of 400 particles. When the particle shape is spherical, the diameter of the sphere is taken as the particle size; for particles other than spheres, the diameter of the equivalent circle calculated from the microscope image (the positive square root of {4 × (particle area) / π}) is taken as the particle size. The average primary particle size is applicable to materials such as silica and carbon black.

[0060] "The softening point of the resin component" is the temperature at which the ball drops when the softening point is determined using a ring-and-ball softening point tester, as specified in JIS K 6220-1:2015 7.7.

[0061] The embodiments will now be described in further detail. The following description is merely illustrative of the invention and is not intended to limit the invention. Furthermore, accompanying drawings are used appropriately for illustration, but these drawings are only examples.

[0062] The tire involved in this embodiment is a tire with a tread, the tread being composed of a specified rubber composition, wherein the thickness of the tread is defined as T (mm) and the total content of filler in the rubber composition constituting the tread relative to 100 parts by mass of rubber component is defined as F (parts by mass), and T / F is less than 0.16.

[0063] [tire] The tread according to this embodiment has at least one rubber layer. The composition of the tread is not particularly limited, and it may have two or more rubber layers. For example, it may be composed of a first layer and a second layer, with the outer surface of the first layer forming the tread surface, and the second layer adjacent to the radially inner side of the first layer. The rubber layers constituting the tread may also consist of three or more layers, such as a third layer on the radially inner side of the second layer. When the tread has two or more rubber layers, the rubber composition constituting any one of the rubber layers may be the rubber composition according to this embodiment. Preferably, the first layer is the rubber composition according to this embodiment, and more preferably, all two or more rubber layers are the rubber composition according to this embodiment.

[0064] Figure 1 It is a schematic cross-sectional view showing a portion of a tire. Figure 1 In the diagram, the vertical direction is the tire's radial direction, the horizontal direction is the tire's width direction, and the direction perpendicular to the paper is the tire's circumferential direction.

[0065] Figure 1 The tread has a first layer 6 forming the outer surface of the tread surface 1 and a second layer 7 adjacent to the radially inner side of the first layer 6. Figure 1 The tread has multiple circumferential grooves that extend continuously along the tire circumference.

[0066] The tread thickness T is the thickness of the entire tread measured along the normal to the tread contact surface on the tire equator in a section passing through the tire's axis of rotation.

[0067] In this embodiment, the tread thickness T is preferably 8.0 mm or more, more preferably 8.5 mm or more, and even more preferably 9.0 mm or more. Furthermore, the tread thickness T is preferably 22.0 mm or less, more preferably 21.0 mm or less, and even more preferably 20.0 mm or less.

[0068] In this embodiment, when the tread thickness is defined as T (mm) and the total filler content relative to 100 parts by mass of the rubber composition constituting the tread is defined as F (parts by mass), T / F is less than 0.16. From the viewpoint of the present invention, it is preferable to be less than 0.15, more preferably less than 0.14, further preferably less than 0.13, and particularly preferably less than 0.12. Furthermore, in this embodiment, T / F is preferably greater than 0.04, more preferably greater than 0.05, and further preferably greater than 0.06. The total filler content F (parts by mass) relative to 100 parts by mass of the rubber composition will be described below.

[0069] From the viewpoint of better utilizing the effects of the present invention, the maximum load capacity W of the tire involved in this embodiment is... L The maximum load capacity (kg) is preferably 300 or more, more preferably 400 or more, further preferably 450 or more, even more preferably 500 or more, even more preferably 550 or more, and particularly preferably 600 or more. Furthermore, from the viewpoint of better utilizing the effects of the present invention, the maximum load capacity W... L (kg), for example, can be set to below 1300, below 1200, below 1100, below 1000, below 900, below 800, below 700. In addition, the maximum load capacity W... L The volume of the space occupied by the tire can be increased by increasing the virtual volume V, and vice versa.

[0070] The tire weight G (kg) involved in this embodiment is preferably 6.0 or more, more preferably 6.5 or more, further preferably 7.0 or more, and particularly preferably 7.5 or more. On the other hand, there is no particular limitation on the upper limit of the tire weight G (kg), which is usually 100 or less, for example, it can be set to 80 or less, 60 or less, 40 or less, 20 or less, 15 or less, etc. In addition, the tire weight G can be changed by conventional methods, that is, it can be increased by increasing the specific gravity of the tire or increasing the thickness of the various components of the tire, and vice versa.

[0071] From the viewpoint of the effectiveness of this invention, the tire weight G (kg) relative to the maximum load capacity W L (kg) ratio (G / W) L The G / W ratio is preferably 0.0170 or less, more preferably 0.0160 or less, and even more preferably 0.0150 or less. On the other hand, from the viewpoint of the effectiveness of the present invention, this G / W ratio... L There is no specific limitation on the lower limit value. For example, it can be set to above 0.0110, above 0.0115, above 0.0120, or above 0.0125.

[0072] <Acetone Extraction Amount AE> From the viewpoint of improving the dispersibility of silica, the acetone extraction amount AE (mass%) of the rubber composition constituting the tread is preferably 16.0 or more, more preferably 18.0 or more, further preferably 20.0 or more, even more preferably 22.0 or more, and particularly preferably 25.0 or more. Furthermore, this acetone extraction amount AE (mass%) is preferably 35.0 or less, more preferably 33.0 or less, and even more preferably 31.0 or less. The acetone extraction amount of the rubber composition can be increased by increasing the amount of soluble components mixed in, and decreased by decreasing the amount of soluble components mixed in. Examples of soluble components mixed in the rubber composition include, for example, plasticizers and liquid rubber.

[0073] <F×AE> In the rubber composition constituting the tread, when the total content of filler in the rubber composition relative to 100 parts by mass of the rubber component is defined as F (parts by mass), from the viewpoint of the present invention, F×AE is preferably greater than 2300, more preferably greater than 2500, further preferably greater than 2800, further preferably greater than 3000, further preferably greater than 3200, further preferably greater than 3500, and particularly preferably greater than 3600. On the other hand, there is no particular limitation on the upper limit of F×AE, but it is preferably less than 8000, more preferably less than 7500, and further preferably less than 7000.

[0074] <T×AE> From the viewpoint of the effectiveness of the present invention, T×AE is preferably greater than 350, more preferably greater than 370, further preferably greater than 400, and particularly preferably greater than 420. On the other hand, there is no particular limitation on the upper limit of T×AE, but it is preferably less than 520, more preferably less than 500.

[0075] <t c> The CTAB specific surface area of ​​the silica contained in the rubber composition specified above is defined as C(m²). 2 From the viewpoint of the effectiveness of the present invention, T / C is preferably less than 0.11, more preferably less than 0.10, and even more preferably less than 0.09. On the other hand, there is no particular limitation on the lower limit of T / C, but it is preferably greater than 0.02, more preferably greater than 0.03, and even more preferably greater than 0.04. Regarding the CTAB specific surface area C (m²) of silica... 2 / g), as described below.

[0076] [Rubber Composition] The rubber composition constituting the tread according to this embodiment contains a rubber component and a filler. The rubber component contains isoprene rubber and styrene-butadiene rubber. The isoprene rubber content in the rubber component is 40% by mass or more, and the glass transition temperature (Tg) of the styrene-butadiene rubber is -60°C or less. The filler contains silica, and the silica content is 130 parts by mass or more per 100 parts by mass of the rubber component. Both can be manufactured using the raw materials described below. The rubber composition constituting the tread according to this embodiment (hereinafter referred to as the rubber composition according to this embodiment) will be described.

[0077] <Rubber Composition> The rubber composition according to this embodiment preferably contains diene rubber as a rubber component. As the diene rubber, any substance commonly used in the tire industry can preferably be used. Specifically, examples include isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). These diene rubbers can be used alone or in combination of two or more. The diene rubber content of the rubber composition according to this embodiment is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 98% by mass or more. Alternatively, the rubber composition may be composed solely of diene rubber.

[0078] The rubber composition involved in this embodiment contains isoprene rubber and SBR, preferably isoprene rubber, SBR and BR.

[0079] (Isoprene-based rubber) As isoprene-based rubbers, materials commonly used in the tire industry, such as isoprene rubber (IR) and natural rubber, can be used. Natural rubber, in addition to unmodified natural rubber (NR), includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, grafted natural rubber, and other modified natural rubbers. These isoprene-based rubbers can be used individually or in combination of two or more.

[0080] As for NR, there are no special restrictions, and commonly used materials in the tire industry can be used, such as SIR20, RSS#3, TSR20, etc.

[0081] From the viewpoint of the effects of the present invention, the content of isoprene-based rubber in the rubber component involved in this embodiment is 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more. Furthermore, from the viewpoint of the effects of the present invention, this content is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0082] (SBR) There are no particular limitations on the type of SBR used; solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), etc., can be used. S-SBR is preferred. Modified SBRs (modified S-SBR, modified E-SBR), etc., can also be used. Examples of modified SBRs include SBRs whose ends and / or main chain are modified with compounds (modifiers) having the following functional groups; and modified SBRs coupled with tin, silicon compounds, etc. (condensates, substances with branched structures, etc.). Furthermore, hydrides of these SBRs (hydrogenated SBRs), etc., can also be used. These SBRs can be used individually or in combination of two or more.

[0083] The functional groups of the aforementioned modifier preferably contain at least one element selected from silicon, nitrogen, and oxygen. Examples of such functional groups include amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazo, urea, ether, carbonyl, oxycarbonyl, mercapto, thioether, dithioether, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imide, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy (preferably alkoxy with 1 to 6 carbon atoms), hydroxyl, oxygen, epoxy, etc., with amino and / or alkoxysilyl preferred. As for the amino group, it is preferable to have one or two alkyl-substituted amino groups with 1 to 6 carbon atoms. Specific examples of alkoxysilyl compounds include, for example, trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethylmethoxysilyl, dimethylethoxysilyl, etc.

[0084] As the SBR, both oil-extended and non-oil-extended SBRs can be used. The SBR that can be used in this embodiment can be a commercially available substance from companies such as JSR Corporation, Sumitomo Chemical Co., Ltd., UBE Corporation, Asahi Kasei Corporation, ZSELASTOMERS Corporation, and ARLANXEO Corporation.

[0085] In this embodiment, from the viewpoint of the effectiveness of the present invention, the glass transition temperature Tg of the SBR is -60°C or lower, preferably -62°C or lower, more preferably -65°C or lower, even more preferably -68°C or lower, and particularly preferably -70°C or lower. Furthermore, the glass transition temperature Tg of the SBR refers to the glass transition temperature of each SBR measured by the above-described method for "glass transition temperature Tg of rubber components".

[0086] The styrene content of the SBR is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and even more preferably 22% by mass or more. Furthermore, the styrene content of the SBR is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. The styrene content of the SBR is determined by the above-described method.

[0087] From the viewpoint of ensuring hysteresis loss, the vinyl content of SBR is preferably greater than 5 mol%, more preferably greater than 10 mol%, and even more preferably greater than 15 mol%. Furthermore, from the viewpoint of low fuel consumption performance, the vinyl content of SBR is preferably less than 60 mol%, more preferably less than 50 mol%, and even more preferably less than 40 mol%. In addition, the vinyl content of SBR is determined by the above-described determination method.

[0088] From the viewpoint of the effectiveness of the present invention, the weight-average molecular weight (Mw) of the SBR is preferably greater than 80,000, more preferably greater than 100,000, even more preferably greater than 150,000, and particularly preferably greater than 500,000. Furthermore, from the viewpoint of crosslinking uniformity, Mw is preferably less than 2,000,000, more preferably less than 1,500,000, and even more preferably less than 1,100,000. Moreover, the Mw of the SBR is determined by the above-described measurement method.

[0089] From the viewpoint of the effectiveness of the present invention, the content of SBR in the rubber component is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably greater than 40% by mass, even more preferably 42% by mass or more, even more preferably 44% by mass or more, and particularly preferably 45% by mass or more. Furthermore, the content of SBR in the rubber component is preferably 60% by mass or less, more preferably 58% by mass or less, even more preferably 55% by mass or less, even more preferably 53% by mass or less, and particularly preferably 50% by mass or less.

[0090] (BR) There are no particular limitations on the type of BR used. For example, BR with a cis content of less than 50 mol% (low-cis BR), BR with a cis content of more than 90 mol% (high-cis BR), rare earth-based butadiene rubber synthesized with rare earth element catalysts (rare earth-based BR), BR containing syndiotactic polybutadiene crystals (BR containing SPB), and modified BR (high-cis modified BR, low-cis modified BR), etc., commonly used in the tire industry, can be used. These BRs can be used alone or in combination of two or more.

[0091] As a high-cis BR, for example, commercially available materials from companies such as Zeon Corporation, UBE Corporation, and JSR Corporation can be used. By containing a high-cis BR, low-temperature properties and wear resistance can be improved. The cis content of the high-cis BR is preferably greater than 95 mol%, more preferably greater than 96 mol%, and even more preferably greater than 97 mol%. Furthermore, the cis content of the BR is determined by the aforementioned method.

[0092] As a rare earth-based BR synthesized using a rare earth element catalyst, the vinyl content is preferably less than 1.8 mol%, more preferably less than 1.6 mol%, and even more preferably less than 1.5 mol%, with the cis content preferably greater than 95 mol%, more preferably greater than 96 mol%, and even more preferably greater than 97 mol%. For example, commercially available substances from companies such as Lanxess Corporation can be used as a rare earth-based BR.

[0093] Examples of SPB-containing BRs include 1,2-syndiotactic polybutadiene crystals, which are not simply dispersed within the BR, but rather are chemically bonded to and dispersed with the BR. Commercially available materials from companies such as UBE Corporation can be used as such SPB-containing BRs.

[0094] As a modified BR, in addition to BRs modified with the same functional groups as those described in the above SBR, modified butadiene rubber (modified BR) with functional groups at the ends and / or the main chain modified with at least one element selected from silicon, nitrogen and oxygen can also be used.

[0095] Other modified BRs include those obtained by polymerizing 1,3-butadiene with a lithium initiator followed by the addition of a tin compound, and further, modified BRs whose ends are bonded by tin-carbon bonds (tin-modified BRs). Furthermore, the modified BR can be either non-hydrogenated or hydrogenated.

[0096] From the viewpoint of wear resistance, the weight-average molecular weight (Mw) of BR is preferably greater than 300,000, more preferably greater than 350,000, and even more preferably greater than 400,000. Furthermore, from the viewpoint of crosslinking uniformity, it is preferably less than 2,000,000, more preferably less than 1,000,000, and even more preferably less than 500,000. Moreover, Mw can be determined using the methods described above.

[0097] The content of BR in the rubber component is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, and particularly preferably 10% by mass or more. Furthermore, the content of BR in the rubber component is preferably less than 40% by mass, more preferably less than 30% by mass, even more preferably less than 20% by mass, even more preferably 18% by mass or less, and particularly preferably 16% by mass or less.

[0098] (Other rubber components) Within the scope that does not affect the effects of the present invention, the rubber component may also contain other rubber components besides diene rubbers. As other rubber components besides diene rubbers, crosslinkable rubber components commonly used in the tire industry can be used, such as butyl rubber (IIR), halogenated butyl rubber, ethylene propylene rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber, fluororubber (FKM), acrylic rubber (ACM), chlorohydrin rubber, and other non-diene rubbers. Furthermore, in addition to the above-mentioned rubber components, it may contain or not contain known thermoplastic elastomers. Other rubber components may be used alone or in combination of two or more.

[0099] (Rubber components synthesized from raw materials derived from recycled / biomass) The monomers used as building blocks in synthetic rubbers such as IR, SBR, and BR can be substances derived from underground resources such as petroleum and natural gas, or substances recycled from rubber products such as tires or non-rubber products such as polystyrene. There are no particular limitations on the monomers obtained through recycling (recycled monomers), and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl compounds. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. There are no particular limitations on the aromatic vinyl compounds, and examples include styrene. Preferably, recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are used as raw materials.

[0100] There are no particular limitations on the method for manufacturing the recycled monomer. For example, it can be synthesized from recycled naphtha obtained by pyrolyzing rubber products such as tires. Furthermore, there are no particular limitations on the method for manufacturing the recycled naphtha. For example, rubber products such as tires can be pyrolyzed under high temperature and pressure, microwave pyrolysis can be used, or it can be extracted after mechanical crushing.

[0101] Furthermore, the monomers that form the building blocks of polymers such as IR, SBR, and BR can also be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. There are no particular limitations on what constitutes biomass; examples include substances derived from agricultural, forestry, and aquatic products, sugars, sawdust, plant residues after the extraction of useful components, plant-derived ethanol, and biomass naphtha.

[0102] As for the monomers derived from biomass (biomass monomers), there are no particular limitations, and examples include butadiene derived from biomass and aromatic vinyl compounds derived from biomass. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl compounds include styrene, etc., without particular limitations. Furthermore, the method of manufacturing the monomers derived from biomass is not particularly limited; for example, substances obtained through biological and / or chemical and / or physical transformations of plants and animals can be listed. Representative examples of biological transformations include microbial fermentation; examples of chemical and / or physical transformations include catalyst-based transformations, high-temperature transformations, high-pressure transformations, electromagnetic wave-based transformations, supercritical fluid-based transformations, and combinations thereof.

[0103] The term "biomass polymer" is not particularly limited to polymers synthesized from biomass monomer components, but may include examples such as polybutadiene rubber synthesized from butadiene derived from biomass, and aromatic vinyl / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl compounds derived from biomass. Examples of such aromatic vinyl / butadiene copolymers include, for instance, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass.

[0104] Whether the polymer's raw material is derived from biomass can be determined by measuring the pMC (percent Modern Carbon) according to ASTM D6866-10. pMC refers to the percentage of modern carbon in the sample. 14 C concentration relative to standard modern carbon (modern standard reference) 14 The C concentration ratio is a value used as an indicator of the proportion of compounds in biomass. The significance of this value is described below.

[0105] One mole of carbon atoms (6.02 × 10⁻⁶) 23 Of these, approximately one trillionth exists, which is about 6.02 × 10⁻⁶ carbon atoms. 11 indivual 14 C. 14 The half-life of C is 5730 years. 14 C decreases systematically. Therefore, it is believed that carbon dioxide and other atmospheric substances, after being absorbed and fixed by plants and other organisms, have undergone more than 226,000 years of aging in fossil fuels such as coal, oil, and natural gas. The carbon dioxide contained in these fossil fuels during their initial fixation... 14 All carbon (C) decays. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain absolutely no carbon. 14 Therefore, the chemicals produced using these fossil fuels as raw materials also contain absolutely no carbon (C). 14 C element.

[0106] on the other hand, 14 C is continuously generated through nuclear reactions in the atmosphere via cosmic rays. Therefore, 14 C reaches equilibrium between the reduction of radioactive decay and the generation from nuclear reactions in Earth's atmosphere. 14 The amount of C is a constant. Therefore, in the current environment, the biomass resources from which the material cycle originates... 14 The C concentration, as described above, is approximately 1 × 10⁻⁶ relative to all C atoms. -12 These are values ​​approximately in mol%. Therefore, by using the differences between these values, the proportion of biomass in a compound can be calculated.

[0107] Typically, the 14 C was determined as described below. Accelerator mass spectrometry based on a tandem accelerator was used for the determination. 13 C concentration ( 13 C / 12 C) 14 C concentration ( 14 C / 12 C) Determination. During the determination, as... 14 The standard for carbon concentration in modern times is based on the carbon cycling in nature in 1950. 14 C concentration. As a specific standard substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) was used. The radioactivity of carbon in this oxalic acid (carbon content per gram of carbon) was determined. 14 The radioactivity intensity of carbon (C) is classified according to its carbon isotopes. 13 The C-correction is a fixed value, using the value with attenuation correction applied from 1950 to the date of measurement as the standard. 14 The C concentration value (100%) is used. The ratio of this value to the value of the actual sample measured is the pMC value.

[0108] Therefore, if the rubber is made from materials 100% derived from biomass, then despite regional differences, it is expected to have a value of around 110 pMC, as it is generally not 100 pMC under normal conditions. On the other hand, for chemicals derived from fossil fuels such as petroleum, the measured... 14 At C concentrations, the value is around 0 pMC (e.g., 0.3 pMC). This value corresponds to 0% of the biomass ratio mentioned above.

[0109] In summary, using rubber and other materials with high pMC values, i.e., rubber and other materials with a high proportion of biomass, in rubber compositions is preferred from an environmental protection perspective.

[0110] <packing> The rubber composition according to this embodiment contains 130 parts by mass or more of silica as a filler relative to 100 parts by mass of the rubber component. Furthermore, the filler preferably contains silica and carbon black, but the filler may also be composed of carbon black and silica.

[0111] (Silicon dioxide) There are no particular limitations on the silica used; for example, silica commonly used in the tire industry, such as silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica), can be used. There are also no particular limitations on the raw materials used for silica; for example, it can be derived from minerals such as quartz, or from biological sources such as rice husks (e.g., silica made from biomass materials such as rice husks), or silica recovered from silica-containing products. However, hydrated silica prepared by a wet process is preferred due to its higher silanol group content. These silicas can be used individually or in combination of two or more types.

[0112] Silica obtained from biomass materials, for example, can be extracted from rice husk ash obtained by burning rice husks using sodium hydroxide solution. This silicate is then reacted with sulfuric acid in the same way as conventional wet silica, and the resulting silica precipitate is filtered, washed, dried, and pulverized to obtain the final product.

[0113] Silica recovered from products containing silica can be, for example, silica recovered from products containing silica such as electronic components like semiconductors, tires, desiccants, and filter materials such as diatomaceous earth. Furthermore, the method of recovery is not particularly limited, and examples include pyrolysis and electromagnetic wave-based pyrolysis. Of these, silica recovered from electronic components like semiconductors or tires is preferred.

[0114] If silica crystallizes, it becomes insoluble in water, making its silicic acid component unusable. By managing the combustion temperature and time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Application Publication No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol.6, pp.216-222, etc.). Amorphous silica extracted from rice husks can be obtained using commercially available materials from Wilmar Corporation, etc.

[0115] From the viewpoint of the effectiveness of the present invention, the preferred CTAB specific surface area C of silicon dioxide is 110 m². 2 / g or more, preferably 140m 2 / g or more, preferably 170m 2 / g or more, preferably 190m 2 / g or more, especially preferably 200mg 2 / g or more. Furthermore, the specific surface area C of this CTAB is more preferably 300m². 2 / g or less, more preferably 280m 2 / g or less, more preferably 260m 2 / g or less. Furthermore, the CTAB content of silica was determined using the methods described above.

[0116] From the viewpoint of the effectiveness of the present invention, the nitrogen adsorption specific surface area (N2SA) of silica is preferably greater than 110 m². 2 / g, more preferably greater than 130m 2 / g, more preferably greater than 150m 2 / g, more preferably greater than 170m 2 / g, more preferably greater than 190m 2 / g, particularly preferably greater than 210m 2 / g. Furthermore, the N2SA is preferably less than 350m. 2 / g, more preferably less than 320m 2 / g, further preferably less than 280m 2 / g. Furthermore, the N2SA content of silica was determined using the method described above.

[0117] From the viewpoint of the effectiveness of the present invention, the average primary particle size of silica is preferably greater than 8 nm, more preferably greater than 10 nm, and even more preferably greater than 12 nm. Furthermore, this average primary particle size is preferably less than 20 nm, more preferably less than 19 nm, even more preferably less than 18 nm, even more preferably less than 17 nm, and particularly preferably less than 16 nm. Moreover, the average primary particle size of silica is determined by the above-described measurement method.

[0118] From the viewpoint of the effects of the present invention, the silica content relative to 100 parts by weight of the rubber component is 130 parts by weight or more, preferably 135 parts by weight or more, more preferably 140 parts by weight or more, and even more preferably 150 parts by weight or more. Furthermore, from the viewpoint of compatibility with isoprene-based rubbers, this content is preferably 200 parts by weight or less, more preferably 190 parts by weight or less, and even more preferably 180 parts by weight or less.

[0119] From the viewpoint of the effects of the present invention, the silica content in the filler is preferably 55% by mass or more, more preferably 65% ​​by mass or more, even more preferably 75% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more. Furthermore, from the viewpoint of wear resistance, it is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0120] (Carbon black) As for carbon black, there are no particular limitations; examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw materials for carbon black can be biomass materials such as lignin and vegetable oil, or thermal cracking oil obtained by pyrolysis of waste tires. Furthermore, carbon black can be manufactured using combustion-based methods such as the furnace method, hydrothermal carbonization (HTC) methods, or methane thermal cracking methods such as the thermal cracking carbon black method. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Nippon Steel Carbon Black Co., Ltd., Columbia Carbon Co., Ltd., etc. These carbon blacks can be used individually or in combination of two or more types.

[0121] In addition to the above, from the perspective of life cycle assessment, recycled carbon black, which is produced by thermally cracking and refining carbon black made from biomass materials such as lignin and carbon black-containing products such as tires, can also be used as carbon black, in addition to the above.

[0122] In this specification, "recycled carbon black" refers to carbon black obtained by pulverizing used products such as tires containing carbon black, and then burning the pulverized material. Based on the thermogravimetric determination method of JIS K 6226-2:2003, when it is oxidized and burned in air, the proportion of its non-combustible components, i.e., ash content, is 13% by mass or more. That is, the proportion of the mass of the carbon content (reduced weight) based on the above-mentioned loss during oxidative combustion is 87% by mass or less. Recycled carbon black is sometimes also represented as rCB.

[0123] Recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975 describes, "Rubber Chemistry and Technology", Vol. 85, No. 3, pp. 408-449 (2012), especially pp. 438, 440, 442, which mentions that it can be obtained by removing oxygen and then performing pyrolysis of organic materials at 550-800°C, or by vacuum pyrolysis at a relatively low temperature (

[0027] ). The carbon black obtained by such a pyrolysis process, as mentioned in

[0004] of Patent No. 6856781, is usually a regenerated carbon black lacking functional groups on its surface (Comparison of surface morphology and chemical properties of pyrolysis carbon black and commercially available carbon black, Powder Technology 160 (2005) 190-193).

[0124] Recycled carbon black can be carbon black lacking functional groups on its surface, or it can be carbon black that has been treated to contain functional groups on its surface. The treatment to contain functional groups on the surface of recycled carbon black can be carried out by conventional methods. For example, in European Patent Application Publication No. 3173251, carbon black containing hydroxyl and / or carboxyl groups on its surface is obtained by treating carbon black obtained from a pyrolysis process with potassium permanganate under acidic conditions. Furthermore, in Patent No. 6856781, carbon black obtained from a pyrolysis process is treated with an amino acid compound containing at least one thiol or disulfide group to obtain carbon black with an activated surface. The recycled carbon black involved in this embodiment includes these carbon blacks treated to contain functional groups on their surface.

[0125] Recycled carbon black can use commercially available materials from companies such as Strable Green Carbon and LD Carbon.

[0126] From a reinforcing perspective, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably greater than 70 m². 2 / g, more preferably greater than 90m 2 / g, more preferably greater than 110m 2 / g, particularly preferably greater than 130m 2 / g. Furthermore, from the viewpoint of exothermic properties and processability, a value of less than 250m is preferred. 2 / g, more preferably less than 220m 2 / g, further preferably less than 190m 2 / g. Furthermore, the N2SA of carbon black was determined using the method described above.

[0127] The average primary particle size of the carbon black is preferably less than 35 nm, more preferably less than 30 nm, even more preferably less than 27 nm, even more preferably less than 23 nm, and particularly preferably less than 19 nm. Furthermore, the average primary particle size is preferably greater than 8 nm, more preferably greater than 10 nm, even more preferably greater than 12 nm, and particularly preferably greater than 14 nm. The average primary particle size of the carbon black is determined by the method described above.

[0128] From the viewpoint of wear resistance, the carbon black content relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more. Furthermore, this content is preferably less than 50 parts by mass, more preferably less than 40 parts by mass, even more preferably less than 30 parts by mass, even more preferably less than 20 parts by mass, and particularly preferably less than 15 parts by mass.

[0129] (Other fillers) The filler may also contain fillers other than silica and carbon black. There are no particular limitations on these other fillers; for example, aluminum hydroxide, calcium carbonate, alumina, clay, talc, and other substances commonly used in the tire industry can be mixed in. These other fillers can be used alone or in combination of two or more.

[0130] In this embodiment, the total filler content F in the rubber composition relative to 100 parts by mass of the rubber component is 130 parts by mass or more, preferably 135 parts by mass or more, more preferably 140 parts by mass or more, even more preferably 145 parts by mass or more, even more preferably 150 parts by mass or more, even more preferably 155 parts by mass or more, and even more preferably 160 parts by mass or more. Furthermore, this content F is preferably 200 parts by mass or less, more preferably 195 parts by mass or less, and even more preferably 190 parts by mass or less.

[0131] <Silane Coupling Agent> Silica is preferably used in combination with a silane coupling agent. There are no particular limitations on the silane coupling agent; any silane coupling agent conventionally used in the tire industry in combination with silica can be used. However, for the purpose of obtaining the desired effect more preferably, one or more silane coupling agents selected from sulfide-based silane coupling agents and mercapto-based silane coupling agents are preferred, and mercapto-based silane coupling agents are more preferred.

[0132] Examples of sulfide-based silane coupling agents include, for example, bis(3-triethoxysilylpropyl) disulfide and bis(3-triethoxysilylpropyl) tetrasulfide. These sulfide-based silane coupling agents can be used alone or in combination of two or more.

[0133] In this specification, mercapto-based silane coupling agents refer to silane coupling agents having a mercapto group and silane coupling agents in which the mercapto group is protected by a protecting group. There are no particular limitations on mercapto-based silane coupling agents; for example, compounds having a mercapto group represented by formula (2), compounds with a mercapto group protected by an ester group represented by formula (3), and compounds containing a binding unit A represented by formula (4) and / or a binding unit B represented by formula (5) are examples. Among these, compounds represented by formula (3) or compounds containing a binding unit A represented by formula (4) and / or a binding unit B represented by formula (5) are preferred for better application of the present invention; compounds represented by formula (3) are more preferred. These mercapto-based silane coupling agents can be used alone or in combination of two or more.

Chemical Formula 1

Chemical Formula 2

Chemical Formula 3

[0134] Examples of compounds represented by formula (2) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, or compounds represented by formula (6) below. These may be used alone or in combination of two or more. [Chemical Formula 5]

[0135] Examples of compounds represented by formula (3) include 3-octanoylthio-1-propyltriethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, and 3-octanoylthio-1-propyltrimethoxysilane.

[0136] Compounds containing binding unit A represented by formula (4) and / or binding unit B represented by formula (5) can suppress viscosity rise during processing compared to sulfide-based silane coupling agents such as bis-(3-triethoxysilylpropyl)tetrasulfide. Therefore, it can be considered that the dispersibility of silica is improved, and the low-burning performance, wet grip, and elongation at break are further enhanced. This can be attributed to the fact that the sulfide portion of binding unit A is a CSC bond, thus exhibiting higher thermal stability and less Mooney viscosity rise compared to tetrasulfides and disulfides.

[0137] From the viewpoint of suppressing viscosity increase during processing, the content of binding unit A is preferably 30 to 99 mol%, more preferably 50 to 90 mol%. Furthermore, the content of binding unit B is preferably 1 to 70 mol%, more preferably 5 to 65 mol%, and even more preferably 10 to 55 mol%. In addition, the total content of binding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. Furthermore, the content of binding units A and B also includes the amount when binding units A and B are located at the end of the silane coupling agent. The morphology of binding units A and B when located at the end of the silane coupling agent is not particularly limited, as long as they are formed in the units corresponding to formulas (4) and (5) representing binding units A and B.

[0138] In a compound comprising binding unit A represented by formula (4) and binding unit B represented by formula (5), the total number of repetitions (x+y) of binding unit A and binding unit B is preferably in the range of 3 to 300. Within this range, due to the -C7H of binding unit A... 15 The thiol silane coated with binding unit B thus ensures good reactivity with silica and rubber components while suppressing the shortening of scorch time.

[0139] Compounds comprising binding unit A represented by formula (4) and / or binding unit B represented by formula (5) include, for example, NXT-Z30, NXT-Z45, NXT-Z60, NXT-Z100, etc. manufactured by Momentive. These can be used alone or in combination of two or more.

[0140] Silane coupling agents other than sulfide-based and mercapto-based silane coupling agents are not particularly limited. Examples include vinyl-based silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidyloxy-based silane coupling agents such as γ-glycidyloxypropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane; 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. These other silane coupling agents can be used alone or in combination of two or more. As one of the silane coupling agents listed above, for example, silane coupling agents manufactured and sold by Momentive Corporation, Evonik Industries, etc., can be used.

[0141] From the viewpoint of improving the dispersibility of silica, the content of the silane coupling agent (preferably one or more silane coupling agents selected from sulfide-based silane coupling agents and mercapto-based silane coupling agents) relative to 100 parts by mass of silica is preferably 1.0 parts by mass or more, more preferably 3.0 parts by mass or more, and even more preferably 5.0 parts by mass or more. Furthermore, from the viewpoint of cost and processability, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less.

[0142] <Plasticizer> Plasticizers are materials that impart plasticity to rubber components, encompassing both liquid plasticizers at 25°C and solid plasticizers at 25°C. Examples of plasticizers include resin components, oils, liquid rubber, and ester-based plasticizers. These plasticizers can be derived from mineral resources such as petroleum and natural gas, biomass, or petroleum naphtha recovered from rubber and non-rubber products. Furthermore, low-molecular-weight hydrocarbon components obtained through the thermal cracking and extraction of used tires and products containing various components can also be used as plasticizers. The rubber composition according to this embodiment preferably contains a resin component as a plasticizer. The resin component preferably contains at least one selected from C9-based resins, dicyclopentadiene-based resins, and terpene-based resins; the presence of a liquid resin is also preferred. Furthermore, the rubber composition according to this embodiment preferably contains liquid rubber, and the presence of vegetable oil is also preferred. A single plasticizer or two or more plasticizers can be used in combination.

[0143] (Resin composition) The rubber composition described in this embodiment can also be used in combination with resin components. In this embodiment, there are no particular limitations on the resin components that can be used; resins commonly used in the tire industry can be used, such as C9-based resins, C5-based resins, C5C9-based resins, dicyclopentadiene-based resins, aromatic vinyl-based resins, coumarone-based resins, indene-based resins, terpene-based resins, rosin-based resins, phenolic resins, etc. These resin components can be used individually or in combination of two or more. Each resin component can also be used individually or in combination of two or more.

[0144] C9 series resins "C9 series resin" refers to resin obtained by polymerizing C9 fractions. It can be a polymer obtained by homopolymerization of the C9 fraction or a copolymer obtained by copolymerization of the C9 fraction with other components. For example, a resin copolymerized with dicyclopentadiene (DCPD) and a C9 fraction is called DCPD / C9 resin. Furthermore, this C9 series resin can also be its hydrogenated or modified products. Examples of C9 fractions include, for example, petroleum fractions with 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, coumarone, indene, methyl indene, and dicyclopentadiene. Examples of C9 series resins include, for example, commercially available substances from companies such as BASF, Zeon Corporation, and ENEOS Corporation.

[0145] C5 series resins "C5 series resins" refer to resins obtained by polymerizing C5 fractions, or their hydrogenated or modified products. Examples of C5 fractions other than dicyclopentadiene include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, isoprene, 2-methyl-1-butene, 2-methyl-2-butene, and 1-pentene. Commercially available materials from companies such as STRUKTOL, Zeon Corporation, and ENEOS Corporation can be used as C5 series resins.

[0146] C5C9 series resins "C5C9 series resin" refers to resin obtained by copolymerizing the aforementioned C5 fraction with the aforementioned C9 fraction, or their hydrogenated or modified products. For example, commercially available substances from Tosoh Corporation, LUHUA Corporation, etc., can be used as C5C9 series petroleum resins.

[0147] Dicyclopentadiene-based resins "Dicyclopentadiene-based resin" refers to a resin containing cyclopentadiene (CPD) and / or dicyclopentadiene (DCPD) as the most abundant monomeric component, or their hydrogenated or modified products. As a dicyclopentadiene-based resin, polymers polymerized solely with dicyclopentadiene as a monomer, or copolymers of dicyclopentadiene and the aforementioned C9 fraction (DCPD / C9 resin) are preferred. As a dicyclopentadiene-based resin, commercially available materials from ExxonMobil, ENEOS Corporation, Zeon Corporation of Japan, Maruzen Petrochemical Co., Ltd., etc., can be used.

[0148] Aromatic Vinyl Resins "Aromatic vinyl resins" refer to resins containing aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene as the most abundant monomer components, or their hydrogenated or modified products. For economic reasons, ease of processing, and excellent exothermic properties, homopolymers of α-methylstyrene or styrene, or copolymers of α-methylstyrene and styrene, are preferred as aromatic vinyl resins, with copolymers of α-methylstyrene and styrene being more preferred. For example, commercially available substances from companies such as Kraton, Eastman Chemical Company, and Mitsui Chemicals Co., Ltd. can be used as aromatic vinyl resins.

[0149] Coumarin-based resins "Coumarone-based resins" refer to resins containing coumarone as a monomer, or their hydrogenated or modified products. Examples of coumarone-based resins include, for instance, coumarone resins made from polymers containing only coumarone as a monomer, coumarone / indene resins made from copolymers of coumarone and indene as monomers, and coumarone / indene / styrene resins made from copolymers of coumarone, indene, and styrene as monomers. Commercially available substances from Rutgers Corporation, Nippon Paint Co., Ltd., and Mitsui Chemicals Co., Ltd., can be used as coumarone-based resins.

[0150] Indene resins "Indene-based resins" refer to resins containing indene as a monomer, or their hydrogenated or modified products. Examples of preferred indene-based resins include coumarone / indene resins, copolymers of coumarone and indene as monomers, and coumarone / indene / styrene resins, copolymers of coumarone, indene, and styrene as monomers. Commercially available indene-based resins, such as those from Rutgers Corporation, Nippon Paint Co., Ltd., and Mitsui Chemicals Co., Ltd., can also be used.

[0151] Terpene Resins "Terpene-based resin" refers to a resin containing terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as monomeric components, or their hydrogenated or modified products. Examples of terpene-based resins include, for instance, polyterpene resins, polymers containing only one or more of the aforementioned terpene compounds as monomeric components; aromatic-modified terpene resins, copolymers containing the aforementioned terpene compounds and aromatic compounds as monomeric components; and terpene-phenol resins, copolymers containing the aforementioned terpene compounds and phenolic compounds as monomeric components. Examples of aromatic compounds that are monomeric components of aromatic-modified terpene resins include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds that are monomeric components of terpene-phenol resins include phenol, bisphenol A, cresol, and xylenol. For example, commercially available substances from companies such as Yasuhara Chemical Co., Ltd., Arakawa Chemical Industry Co., Ltd., and Nippon Terpene Chemical Co., Ltd. can be used as terpene-based resins.

[0152] Rosin-based resins "Rosin-based resin" refers to resins containing abietic acid compounds such as abietic acid, neoabietic acid, palustric acid, and isopimaric acid, or their hydrogenated or modified products. There are no particular limitations on the definition of a rosin-based resin; examples include natural rosin resin and rosin-modified resins modified by hydrogenation, disproportionation, dimerization, esterification, etc. For example, commercially available substances from companies such as Halima Chemical Co., Ltd., Arakawa Chemical Industry Co., Ltd., and IREC Co., Ltd. can be used as rosin-based resins.

[0153] Phenolic Resins "Phenolic resins" refer to resins containing phenolic compounds such as phenol and cresol as monomers, or their hydrogenated or modified products. There are no particular limitations on the term "phenolic resin," and examples include phenolic resins, alkylphenolic resins, alkylphenol-formaldehyde resins, oil-modified phenolic resins, and terpene phenolic resins. For example, commercially available substances from companies such as Sumitomo Bakelite Co., Ltd., DIC Co., Ltd., and Asahi Organic Materials Co., Ltd. can be used as phenolic resins.

[0154] Liquid Resin The resin component can also be a liquid resin that is liquid at 25°C. There are no particular limitations on the type of liquid resin; examples include liquid aromatic vinyl resins, liquid C9 resins, liquid C5C9 resins, and liquid coumarone / indene resins. These liquid resins can be used alone or in combination of two or more.

[0155] The weight-average molecular weight (Mw) of the liquid resin is typically less than 10,000, preferably 9,000 or less, more preferably 6,000 or less, and even more preferably 4,500 or less. Furthermore, the Mw of the liquid resin is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, even more preferably 1,500 or more, and particularly preferably 2,000 or more.

[0156] From the viewpoint of wet grip performance, the softening point of the resin component is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher. Furthermore, from the viewpoint of processability and improving the dispersibility of the rubber component and filler, it 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 determined by the above-described method.

[0157] The content of resin component relative to 100 parts by weight of rubber component (the total amount when multiple resin components are used together) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, even more preferably 50 parts by weight or more, and particularly preferably 55 parts by weight or more. On the other hand, from the viewpoint of suppressing heat generation, this content is preferably 100 parts by weight or less, more preferably 90 parts by weight or less, and even more preferably 80 parts by weight or less.

[0158] The total content of C9 resin, dicyclopentadiene resin, and terpene resin relative to 100 parts by weight of the rubber component is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, even more preferably 50 parts by weight or more, and particularly preferably 55 parts by weight or more. On the other hand, from the viewpoint of suppressing heat generation, this content is preferably 100 parts by weight or less, more preferably 90 parts by weight or less, and even more preferably 80 parts by weight or less.

[0159] (Oil) Examples of oils include mineral oils, vegetable oils, and animal oils. Furthermore, from a life cycle assessment perspective, refined waste oil from rubber mixers or engines, or refined waste cooking oil used in restaurants, can also be used. One type of oil can be used alone, or two or more can be used in combination.

[0160] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oils include paraffinic oils, naphthenic oils, and aromatic oils. Specific examples of mineral oils include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract). Furthermore, due to environmental measures, oils with lower polycyclic aromatic compounds (PCA) content may also be used. Examples of low PCA content oils include MES, TDAE, and heavy naphthenic oils. Mineral oils may be used alone or in combination of two or more types.

[0161] In this instruction manual, "vegetable oil" refers to, for example, flaxseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla seed oil, castor oil, tung oil, pine oil, pine tar, sunflower seed oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and beeswax. Furthermore, as vegetable oils, refined oils (salad oil, etc.) obtained by refining the above oils can also be included, transesterified oils obtained by transesterification of the above oils, hydrogenated oils obtained by hydrogenation of the above oils, thermally polymerized oils obtained by thermal polymerization of the above oils, oxidized polymerized oils obtained by oxidizing the above oils, and waste edible oils recovered from oils used as edible oils, etc. In addition, vegetable oils can be liquid or solid at 25°C. One type of vegetable oil can be used alone, or two or more can be used in combination.

[0162] The vegetable oil involved in this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. Furthermore, in this specification, acylglycerol refers to a compound in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. There is no particular limitation on the type of acylglycerol; it can be any one of 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Further, acylglycerol can be a monomer, a dimer, or a polymer of more than one trimer. Moreover, acylglycerols of more than one trimer can be obtained by thermal polymerization, oxidative polymerization, etc. Furthermore, acylglycerol can be liquid or solid at 25°C.

[0163] There is no particular limitation on the method for confirming whether a rubber composition contains acylglycerol; it can be achieved through... 1 Confirmed by ¹H-NMR determination. For example, a rubber composition containing triacylglycerol was impregnated in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, the determination was performed at room temperature. 1 In H-NMR, with the tetramethylsilane (TMS) signal set to 0.00 ppm, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm. It is speculated that these signals originate from hydrogen atoms bonded to the carbon atom adjacent to the oxygen atom of the ester group. Furthermore, "around" in this paragraph refers to a range of ±0.10 ppm.

[0164] The fatty acids mentioned above are not specifically limited and can be either unsaturated or saturated fatty acids. 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.

[0165] Among these, fatty acids with fewer double bonds are preferred, namely saturated fatty acids or monounsaturated fatty acids, with oleic acid being the most preferred. As a vegetable oil containing such fatty acids, for example, vegetable oils containing saturated fatty acids or monounsaturated fatty acids can be used, or vegetable oils that have undergone transesterification or other modifications can be used. Furthermore, to produce such vegetable oils containing fatty acids, plants can be improved through variety improvement, genetic engineering, gene editing, etc.

[0166] As a vegetable oil, for example, commercially available substances from companies such as Idemitsu Kosan Co., Ltd., Sankyo Oil & Chemical Co., Ltd., ENEOS Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nissin Orisoy Group Co., Ltd. can be used.

[0167] Examples of animal fats include fish oil, tallow, or oleoyl alcohols derived from these.

[0168] When oil is present, from the viewpoint of the effectiveness of the present invention, its content relative to 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, even more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more. Furthermore, this content is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and even more preferably 60 parts by weight or less.

[0169] (Liquid rubber) Liquid rubber is not specifically limited to any polymer that is liquid at 25°C. Examples include liquid butadiene rubber (liquid BR), liquid styrene-butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene-isoprene rubber (liquid SIR), and liquid farnesene rubber. These liquid rubbers can be used individually or in combination of two or more types.

[0170] The weight-average molecular weight (Mw) of the liquid rubber is typically less than 10,000, preferably less than 9,000, more preferably less than 6,000, and even more preferably less than 4,500. Furthermore, the Mw of the liquid rubber is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, even more preferably 1,500 or more, and particularly preferably 2,000 or more. When the Mw of the liquid rubber is within the above range, the effects of the present invention tend to be obtained better. Furthermore, in this specification, liquid rubber is not included in the above-described rubber components.

[0171] When liquid rubber is present, from the viewpoint of the effectiveness of the present invention, its content relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, and particularly preferably 10 parts by mass or more. Furthermore, this content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, further preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0172] (Ester-based plasticizers) 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 tri(xyl) phosphate (TXP). Ester-based plasticizers can be used alone or in combination of two or more.

[0173] From the viewpoint of wet grip performance, the content of plasticizer relative to 100 parts by weight of rubber component (the total amount when multiple plasticizers are used together) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, and particularly preferably 50 parts by weight or more. Furthermore, from the viewpoint of processability, it is preferably 150 parts by weight or less, more preferably 140 parts by weight or less, even more preferably 130 parts by weight or less, and particularly preferably 120 parts by weight or less.

[0174] Anti-aging agents As an antioxidant, there are no particular limitations; examples include naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octyl 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'-xylyl-p-phenylenediamine. Antioxidants based on p-phenylenediamines, such as DTPD, N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants, such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants, such as 2,6-di-tert-butyl-4-methylphenol and styrene-modified phenol; and bis, tri, and polyphenol-based antioxidants, such as tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, with polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline being more preferred. Commercially available products, for example, can be made by companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., and Flexis. Antioxidants can be used alone or in combination of two or more.

[0175] When antioxidants are present, their content relative to 100 parts by weight of the rubber component (the total amount when multiple antioxidants are used together) is preferably 1.0 parts by weight or more, more preferably 2.0 parts by weight or more, even more preferably 3.0 parts by weight or more, even more preferably 3.5 parts by weight or more, and particularly preferably 4.0 parts by weight or more. Furthermore, this content is preferably 10 parts by weight or less, more preferably 8.0 parts by weight or less, and even more preferably 6.0 parts by weight or less.

[0176] <Other Compounding Agents> In addition to rubber components and fillers, the rubber composition involved in this embodiment may also contain appropriate compounding agents commonly used in the tire industry, such as vulcanized rubber particles, processing aids, waxes, stearic acid, zinc oxide, vulcanizing agents, vulcanization accelerators, etc.

[0177] (vulcanized rubber particles) Vulcanized rubber granules are granules made of vulcanized rubber. Specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the perspective of environmental concerns and cost, recycled rubber powder made from waste tire shreds is preferred. These vulcanized rubber granules can be made from one type alone or from two or more types in combination.

[0178] There are no particular limitations on the vulcanized rubber granules; they can be either unmodified or modified vulcanized rubber granules. Commercially available vulcanized rubber products, for example, can be products from companies such as Lehigh Corporation and Muraoka Rubber Industry Co., Ltd.

[0179] When vulcanized rubber particles are present, their content relative to 100 parts by mass of the rubber component can be appropriately adjusted, for example, within a range of greater than 1 part by mass and less than 80 parts by mass.

[0180] (Processing aids) Examples of processing aids include, for example, fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, fatty acid esters, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. Commercially available substances from companies such as Schill+Seilacher and Performance-Additives can also be used as processing aids. These processing aids can be used individually or in combination of two or more.

[0181] When processing aids are included, from the viewpoint of improving processability, their content relative to 100 parts by weight of the rubber component is preferably greater than 0.5 parts by weight, more preferably greater than 1.0 parts by weight, and even more preferably greater than 1.5 parts by weight. Furthermore, from the viewpoint of abrasion resistance and tensile strength, it is preferably less than 10 parts by weight, more preferably less than 8.0 parts by weight, and even more preferably less than 5.0 parts by weight.

[0182] (wax) There are no particular limitations on the type of wax used; any substance commonly used in the tire industry can be preferably 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 bran wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes of these, with paraffin wax being preferred. Furthermore, the wax involved in this embodiment is a stearic acid-free wax. For example, commercially available substances such as those from Ouchi Shinsei Chemical Co., Ltd., Nippon Seiwa Co., Ltd., and Paramelt Co., Ltd. can be used. These waxes can be used individually or in combination of two or more.

[0183] When wax is present, from the viewpoint of improving the weather resistance of rubber, its content relative to 100 parts by weight of rubber component is preferably greater than 0.5 parts by weight, more preferably greater than 1.0 parts by weight, and even more preferably greater than 1.5 parts by weight. Furthermore, from the viewpoint of preventing tire whitening caused by frost, it is preferably less than 10 parts by weight, more preferably less than 7.0 parts by weight, and even more preferably less than 5.0 parts by weight.

[0184] (Stearic acid) When stearic acid is present, from a processability point of view, its content relative to 100 parts by weight of the rubber component is preferably greater than 0.5 parts by weight, more preferably greater than 1.0 parts by weight, and even more preferably greater than 1.5 parts by weight. Furthermore, from a vulcanization rate point of view, it is preferably less than 10 parts by weight, more preferably less than 8.0 parts by weight, and even more preferably less than 5.0 parts by weight.

[0185] (Zinc oxide) When zinc oxide is present, from a processability point of view, its content relative to 100 parts by weight of the rubber component is preferably greater than 0.5 parts by weight, more preferably greater than 1.0 parts by weight, and even more preferably greater than 1.5 parts by weight. Furthermore, from a wear resistance point of view, it is preferably less than 10 parts by weight, more preferably less than 8.0 parts by weight, and even more preferably less than 5.0 parts by weight.

[0186] (Vulcanizing agent) Sulfur is preferably used as a vulcanizing agent. Powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, etc., can be used as the sulfur.

[0187] When sulfur is used as a vulcanizing agent, from the viewpoint of ensuring a sufficient vulcanization reaction, its content relative to 100 parts by weight of the rubber component is preferably greater than 0.1 parts by weight, more preferably greater than 0.5 parts by weight, and even more preferably greater than 1.0 parts by weight. Furthermore, from the viewpoint of preventing deterioration, it is preferably less than 5.0 parts by weight, more preferably less than 3.0 parts by weight, and even more preferably less than 2.0 parts by weight. Moreover, 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.

[0188] Other than sulfur, known organic crosslinking agents can also be used as vulcanizing agents. There are no particular limitations on the organic crosslinking agent, as long as it is a substance capable of forming crosslinking chains other than polysulfide bonds. Examples include alkylphenol / sulfur chloride condensates, sodium 1,6-hexamethylene dithiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyl dithio)hexane, and dicumyl peroxide. These organic crosslinking agents can be commercially available substances from companies such as Taoka Chemical Industry Co., Ltd., Lanxess Co., Ltd., and Flexis Co., Ltd.

[0189] (Vulcanization accelerator) There are no particular limitations on the type of vulcanization accelerator. Examples include sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiourea-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, imidazoline-based vulcanization accelerators, xanthate-based vulcanization accelerators, and caprolactam disulfides. These vulcanization accelerators can be used individually or in combination of two or more. However, from the perspective of achieving the desired effect, it is preferable to select one or more vulcanization accelerators from the categories of sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, and guanidine-based vulcanization accelerators.

[0190] Examples of sulfenamide-based sulfidation accelerators include N-tert-butyl-2-benzothiazole sulfenamide (TBBS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), and N,N-dicyclohexyl-2-benzothiazole sulfenamide (DCBS).

[0191] Examples of thiazole-based sulfidation accelerators include 2-mercaptobenzothiazole (MBT) or its salts, di-2-benzothiazole disulfide (MBTS), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, and 2-(2,6-diethyl-4-morpholinothio)benzothiazole. Among these, MBTS and MBT are preferred, and MBTS is more preferred.

[0192] Examples of guanidine-based vulcanization accelerators include, for example, 1,3-diphenylguanidine (DPG), 1,3-di-o-tolueneguanidine, 1-o-toluenebiguanidine, di-o-tolueneguanidine salt of di-o-toluene borates (Hydrogen bis[benzene-o-diolato(2-)-O,O′borate(1-), compound with N,N′-di-o-tolylguanidine), 1,3-di-o-cumenylguanidine, 1,3-di-o-biphenylguanidine, and 1,3-di-o-cumenyl-2-propionylguanidine.

[0193] When a vulcanization accelerator is included, from the viewpoint of ensuring a sufficient vulcanization rate, its content relative to 100 parts by mass of the rubber component (the total amount when multiple vulcanization accelerators are used together) is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, and particularly preferably 4.0 parts by mass or more. Furthermore, from the viewpoint of suppressing blooming, the content of the vulcanization accelerator is preferably 10 parts by mass or less, more preferably 7.0 parts by mass or less.

[0194] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may also be derived from carbon dioxide in the atmosphere. As a method for obtaining these various materials from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process that synthesizes methane from carbon dioxide can be converted.

[0195] [manufacture] The rubber composition described in this embodiment can be manufactured by known methods. For example, it can be manufactured by mixing the above-mentioned components using a rubber mixing apparatus such as an open mill or a closed mixing mill (Banbury mixer, kneader, etc.).

[0196] The mixing process, for example, includes the following basic kneading process: mixing compounding agents and additives other than vulcanizing agents and vulcanization accelerators, and the final mixing process (F mixing): adding vulcanizing agents and vulcanization accelerators to the mixture obtained in the basic kneading process and mixing. Furthermore, the above-mentioned basic kneading process can also be broken down into multiple processes as needed. When breaking down the basic kneading process, the method can be: (1) pre-mixing a portion of the compounding agents and additives, masterbatching them, and then adding the remaining compounding agents and additives to the obtained masterbatch and mixing them, or (2) mixing all the compounding agents and additives mixed in the basic kneading process once, and then remilling the mixture more than once, etc. In the above method (1), the number of masterbatch is not limited, and it can be two or more. In addition, when the number of masterbatch is two or more, it can be in the manner that all the compounding agents and additives used in the basic kneading process are distributed in any masterbatch.

[0197] There are no particular limitations on the mixing conditions. For example, in the basic kneading process, mixing can be carried out at a discharge temperature of 150–170°C for 3–10 minutes, and in the final kneading process, mixing can be carried out at 70–110°C for 1–5 minutes. There are no particular limitations on the vulcanization conditions. For example, vulcanization can be carried out at 150–200°C for 10–30 minutes.

[0198] The tire according to this embodiment, having a tread composed of the above-described rubber composition, can be manufactured by conventional methods. Specifically, the tire can be manufactured by: preparing an unvulcanized rubber composition by mixing the above-described components as needed, extruding it according to the shape of the tread, bonding the resulting tread together with other tire components on a tire forming machine using conventional methods, forming an unvulcanized tire by molding, and manufacturing the resulting unvulcanized tire by heating and pressurizing it in a vulcanizing machine. There are no particular limitations on the vulcanization conditions; for example, vulcanizing at 150–200°C for 10–30 minutes can be cited.

[0199] [use] The tire of this embodiment can be used for any purpose, whether pneumatic or non-pneumatic, including passenger car tires, large passenger car tires, large SUV tires, racing tires, motorcycle tires, heavy-duty tires, and run-flat tires. Furthermore, passenger car tires refer to tires with a maximum load capacity of less than 1400 kg, intended for use in four-wheeled vehicles. Heavy-duty tires refer to tires with a maximum load capacity of 1400 kg or more. In addition to all-season tires and summer tires, the tires involved in this embodiment can also be used as winter tires, such as studless anti-skid tires.

Example

[0200] The following examples (embodiments) are considered preferred in practice, but the scope of the invention is not limited to these examples. Tires obtained according to Tables 1-1 to 2 were studied using the various reagents shown below, and the results calculated based on the evaluation methods described below are shown in Tables 1-1 to 2.

[0201] <Various Reagents> The reagents used in the examples and comparative examples are summarized below. IR-based rubber: TSR20(NR) SBR1: TUFDENE 2000R (S-SBR, styrene content: 25% by mass, vinyl content: 13% by mol%, Tg: -65℃, Mw: 450,000, non-oil-extended) manufactured by Asahi Kasei Corporation SBR2: F1810 (S-SBR, styrene content: 18% by mass, vinyl content: 10% by mol%, Tg: -73℃, containing 5.0 parts by mass of oil-extended oil per 100 parts by mass of rubber solids) manufactured by LG Chem. BR: UBEPOL BR (registered trademark) 150B (unmodified BR, cis content: 97 mol%, Mw: 440,000) manufactured by UBE Co., Ltd. Carbon Black 1: SHOBLACK N134 (N2SA: 148m) manufactured by Cabot Corporation, Japan 2 / g, average primary particle size: 18nm) Carbon Black 2: SHOBLACK N220 (N2SA: 115m) manufactured by Cabot Japan Co., Ltd. 2 / g, average primary particle size: 22nm) Silica 1: ULTRASIL 9100GR (CTAB specific surface area: 200m²) manufactured by Evonik Industries. 2 / g, N2SA: 235m 2 / g) Silica 2: Zeosil Premium SW (CTAB) manufactured by Solvay, with a specific surface area of ​​245 m². 2 / g, N2SA: 258m 2 / g) Silane coupling agent 1: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Industries Silane coupling agent 2: NXT (3-octanoylthio-1-propyltriethoxysilane) manufactured by Evonik Industries. Resin component 1: SYLVATRAXX4401 (a copolymer of α-methylstyrene and styrene, softening point: 85℃) manufactured by Kraton. Resin component 2: SYLVATARAXX4150 (polyterpene resin, softening point: 115℃) manufactured by Kraton. Resin component 3: Oppera PR383 (hydrogenated DCPD / C9 resin, softening point: 103℃) manufactured by ExxonMobil Oil 1: VivaTec 500 (TDAE oil) manufactured by H&R Corporation. Oil 2: Sunflower seed oil manufactured by Nissin Oriyo Group Co., Ltd. (Oleic acid content in the fatty acids: 55% by mass, total content of polyunsaturated fatty acids in the fatty acids: 8% by mass) Liquid resin: Ricon 340 (liquid C5C9 series resin, Mw: 2400) manufactured by Clayville Company. Wax: OZOACE 0355 (paraffin wax) manufactured by Nippon Seiwa Co., Ltd. Anti-aging agent 1: NOCRAC 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd. Antioxidant 2: NOCRAC RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinsei Chemical Co., Ltd. Processing aid: WB16 (a mixture of calcium soap and fatty acid amide) manufactured by STRUKTOL. Stearic acid: Stearic acid beads "TSUBAKI" manufactured by Nippon Oil Co., Ltd. Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Metals & Minerals Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator 1: NOCCELER CZ (N-cyclohexyl-2-benzothiazole sulfenamide (CBS)) manufactured by Ouchi Shinsei Chemical Co., Ltd. Vulcanization accelerator 2: NOCCELER D (1,3-diphenylguanidine (DPG)) manufactured by Ouchi Shinsei Chemical Co., Ltd.

[0202] (Examples and Comparative Examples) According to the compounding formulations shown in Tables 1-1 and 2, sulfur and reagents other than the vulcanization accelerator were mixed for 1-10 minutes using a 1.7L closed Banbury mixer until the discharge temperature reached 150-160°C, yielding a compound. Then, sulfur and the vulcanization accelerator were added to the obtained compound, and the mixture was kneaded for 4 minutes using a twin-screw open mill until 105°C was reached, yielding an unvulcanized rubber composition. Using this unvulcanized rubber composition, the tires were extruded into the shape of a tread using an extruder equipped with a specific die, bonded together with other tire components to produce unvulcanized tires, and vulcanized at 170°C to obtain the test tires (sizes of 205 / 65R15 in Tables 1-1 to 1-3, and 175 / 65R14 in Table 2). The tire weight G of the 205 / 65R15 tires in Tables 1-1 to 1-3 was 8.4 kg, and the tire weight G of the 175 / 65R14 tire in Table 2 was 6.5 kg. In addition, the maximum load capacity W of tires in Tables 1-1 to 1-3 L The weight of the tires in Table 1 is 660 kg, and the weight of the tires in Table 2 is 515 kg. Therefore, the G / W of the test tires in Tables 1-1 to 1-3 is... L The value is 0.0127, and the G / W of each test tire in Table 2 is... L It is 0.0126.

[0203] <Determination of Acetone Extraction (AE) Content> "Acetone Extraction (AE) Amount" is calculated according to JIS K 6229, which involves immersing each vulcanized rubber test piece in acetone for 72 hours to extract soluble components, measuring the mass of each test piece before and after extraction, and then using the following formula. Acetone extraction yield (%) = {(mass of vulcanized rubber test piece before extraction - mass of vulcanized rubber test piece after extraction) / (mass of rubber test piece before extraction)} × 100

[0204] Handling stability at high speeds Each test tire was mounted on all four wheels of a vehicle (domestic FF2000cc), and the vehicle was driven for 10 laps on a dry asphalt test track at approximately 120 km / h. During cornering, the swaying during entry, steering, and exit was evaluated by 20 test drivers using sensory feedback. Evaluations were given on an integer scale of 1 to 5 points (higher scores for less swaying), and the total score for all 20 drivers was calculated. The total score of the benchmark comparison examples (Comparison Example 1 in Tables 1-1 to 1-3, and Comparison Example 4 in Table 2) was converted to a baseline value (100), and the evaluation results of each test tire were expressed as an index proportional to the total score. A higher value indicates better handling stability at high speeds.

[0205] Table 1-1 Table 1-1 (Tire size: 205 / 65R15) Table 1-2 Table 1-22 (Tire size: 205 / 65R15)

[0207] Table 1-3 Table 1-3 (Tire Size: 205 / 65R15)

[0208] Table 2 Table 2 (Tire Size: 175 / 65R14)

[0209] <Implementation Method> Examples of embodiments of the present invention are shown below. [1] A tire, characterized in that, It is a tire with a tread. The tread is composed of a rubber composition containing rubber components and fillers. The rubber composition contains isoprene-based rubber and styrene-butadiene rubber. The content of isoprene-based rubber in the rubber component is 40% by mass or more. The glass transition temperature (Tg) of the styrene-butadiene rubber is below -60℃. The filler contains silicon dioxide. The rubber composition contains 130 or more parts by mass of silicon dioxide relative to 100 parts by mass of the rubber component. When the thickness of the tread is defined as T (mm) and the total content of filler in the rubber composition relative to 100 parts by mass of the rubber component is defined as F (parts by mass), T / F is less than 0.16. [2] The tire according to [1] above, wherein the rubber composition contains 150 or more parts by mass of silicon dioxide relative to 100 parts by mass of the rubber component. [3] According to the tire described in [1] or [2] above, wherein the CTAB specific surface area C of the silica is 190 m². 2 / g or more, preferably 200m 2 / g or more. [4] According to the tire described in [1] above, wherein the rubber composition contains 50 or more parts by mass of resin component relative to 100 parts by mass of the rubber component, preferably 55 or more parts by mass. [5] The tire according to any one of [1] to [4] above, wherein the styrene content of the styrene-butadiene rubber is 20% by mass or more. [6] The tire according to any one of [1] to [5] above, wherein the acetone extraction amount AE (mass%) of the rubber composition is 25.0 or more. [7] The tire according to [4] above, wherein the resin component contains at least one selected from C9 resin, dicyclopentadiene resin and terpene resin. [8] The tire according to any one of [1] to [7] above, wherein the rubber composition contains a mercapto-based silane coupling agent. [9] The tire according to [4] above, wherein the resin component contains liquid resin.

[10] The tire according to any one of [1] to [9] above, wherein the rubber composition contains liquid rubber.

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

[10] above, wherein the rubber composition contains vegetable oil.

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

[11] above, wherein when the acetone extraction amount of the rubber composition is set as AE (mass%), F×AE is greater than 3500, preferably greater than 3600.

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

[12] above, wherein when the acetone extraction amount of the rubber composition is set as AE (mass%), T×AE is greater than 400, preferably greater than 410, and more preferably greater than 420.

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

[13] above, wherein the CTAB specific surface area of ​​the silica is set as C(m²). 2 When T / C is less than 0.10, preferably less than 0.09.

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

[14] above, wherein the maximum load capacity of the tire is set to W. L When the weight of the tire is set as G (kg), G / W L The value is 0.0170 or less, preferably 0.0165 or less, more preferably 0.0160 or less, and even more preferably 0.0150 or less.< / t>

Claims

1. A tire, characterized in that, It is a tire with a tread. The tread is composed of a rubber composition containing rubber components and fillers. The rubber composition contains isoprene-based rubber and styrene-butadiene rubber. The content of isoprene-based rubber in the rubber component is 40% by mass or more. The glass transition temperature (Tg) of the styrene-butadiene rubber is below -60℃. The filler contains silicon dioxide. The rubber composition contains 130 or more parts by mass of silicon dioxide relative to 100 parts by mass of the rubber component. When the thickness of the tread is defined as T, and the total content of filler in the rubber composition relative to 100 parts by mass of the rubber component is defined as F, T / F less than 0.16, The unit of T is mm, and the unit of F is parts by mass.

2. The tire according to claim 1, wherein, The rubber composition contains 150 parts by mass of silicon dioxide relative to 100 parts by mass of the rubber component.

3. The tire according to claim 1 or 2, wherein, The CTAB specific surface area C of the silica is 190 m². 2 / g or more.

4. The tire according to claim 1, wherein, The rubber composition contains 50 or more parts by weight of resin component relative to 100 parts by weight of the rubber component.

5. The tire according to claim 1 or 2, wherein, The styrene-butadiene rubber has a styrene content of 20% by mass or more.

6. The tire according to claim 1 or 2, wherein, The acetone extraction amount AE of the rubber composition is 25.0 or more, where AE is in units of mass.

7. The tire according to claim 4, wherein, The resin component contains at least one selected from C9 series resins, dicyclopentadiene series resins, and terpene series resins.

8. The tire according to claim 1 or 2, wherein, The rubber composition contains a mercapto-based silane coupling agent.

9. The tire according to claim 4, wherein, The resin component contains liquid resin.

10. The tire according to claim 1 or 2, wherein, The rubber composition contains liquid rubber.

11. The tire according to claim 1 or 2, wherein, The rubber composition contains vegetable oil.

12. The tire according to claim 1 or 2, wherein, When the acetone extraction amount of the rubber composition is set as AE, F×AE is greater than 3500, where AE is in units of mass%.

13. The tire according to claim 1 or 2, wherein, When the acetone extraction amount of the rubber composition is set as AE, T×AE is greater than 400, where AE is in units of mass%.

14. The tire according to claim 1 or 2, wherein, When the CTAB specific surface area of ​​the silicon dioxide is set as C, T / C is less than 0.10, where C is in meters (m). 2 / g.

15. The tire according to claim 1 or 2, wherein, Set the maximum load capacity of the tire to W. L When the weight of the tire is set to G, G / W L When W is below 0.0170, L Both G and G are in kg.

16. The tire according to claim 1 or 2, wherein, The content of isoprene-based rubber in the rubber component is less than 80% by mass.

17. The tire according to claim 1 or 2, wherein, The rubber composition contains less than 200 parts by mass of silicon dioxide per 100 parts by mass of the rubber component.

18. The tire according to claim 1 or 2, wherein, T / F is greater than 0.04.

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