Tire

Abstract

Provided is a tire having improved air permeation resistance. A tire which is provided with an inner liner and a barrier rubber that is in contact with the inner liner on the outside of the inner liner in the radial direction of the tire, and which is characterized in that the barrier rubber comprises a rubber composition containing regenerated carbon black, and the air permeability coefficient of the rubber composition constituting the inner liner is less than 18 * 10-11 cm < 3 > cm / (cm < 2 > s cm < Hg >), and the air permeability coefficient of the rubber composition constituting the inner liner is less than 18 * 10-11 cm < 3 > cm / (cm < 2 > s cm < Hg >) is less than 18 * 10-11 cm < 3 > cm / (cm < 2 > s cm < Hg >). The thickness of the inner liner on the equatorial plane of the tire is 1.5 mm or less, and the loss tangent (70 DEG C tan [delta]) of the composite of the insulating rubber and the inner liner at 70 DEG C is 0.22 or less.

Description

Technical Field

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

[0002] In the inner cavity surface of a tire, an airtight layer for maintaining the air pressure of the tire is provided as an air permeation suppression layer. In recent years, the demand for low fuel consumption of automobiles has been increasing, and thus the airtight layer is also being improved. Although research has been conducted on reducing the thickness of the airtight layer or improving the air permeation suppression property for low fuel consumption, on the other hand, there are problems such as curling / stripping at the interface between the airtight layer and the insulation (also called tie gum) layer adjacent to the airtight layer, and further improvement is required. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-165087 Summary of the Invention [Problems to be Solved by the Invention]

[0004] An object of the present invention is to provide a tire with improved air permeation suppression performance. [Means for Solving the Problems]

[0005] The present invention relates to a tire, characterized in that it is a tire having an airtight layer and an insulation in contact with the airtight layer on the radially outer side of the tire in the tire radial direction, the insulation is composed of a rubber composition containing recycled carbon black, and the air permeation coefficient of the rubber composition constituting the airtight layer is less than 18×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), the thickness of the airtight layer on the tire equator plane is 1.5 mm or less, and the loss tangent 70℃tanδ of the composite body of the insulation and the airtight layer at 70°C is 0.22 or less. [Effects of the Invention]

[0006] According to the present invention, a tire with improved air permeation suppression property can be provided.

[0007] Although it is not intended to be limited theoretically, as a reason for the improved air permeation suppression performance in the present invention, the following speculation can be made. That is, it can be considered that by reducing tanδ related to the composite body of the insulation and the airtight layer and thinning the thickness of the composite body, the tire as a whole becomes difficult to heat, and air becomes difficult to pass through. It can be considered that through the synergistic effect of this and improving the air permeation coefficient of the airtight layer, as a tire, it contributes to improving the air permeation suppression performance during driving. Brief Description of the Drawings

[0008]

Figure 1

[0009] The tire related to an embodiment of the present invention is a tire having an inner liner and a butyl layer in contact with the inner liner on the radially outer side of the tire, the butyl layer being composed of a rubber composition containing recycled carbon black, and the air permeability coefficient of the rubber composition constituting the inner liner being less than 18×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), the thickness of the inner liner on the tire equatorial plane being 1.5 mm or less, and the loss tangent 70℃tanδ of the composite body of the butyl layer and the inner liner being 0.22 or less at 70°C.

[0010] The thickness of the above-mentioned inner liner on the tire equatorial plane is preferably 1.4 mm or less, more preferably 1.2 mm or less, and further preferably 1.1 mm or less.

[0011] It is considered that the strain of the inner liner is reduced, heat generation is suppressed, and the air permeation suppression performance is improved.

[0012] The air permeability coefficient of the rubber composition constituting the above-mentioned inner liner is preferably 17×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, more preferably 16×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, further preferably less than 15×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), and further preferably 14.0×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less.

[0013] It can be considered that it can hold air, improve shape stability, and reduce rolling resistance, so that heat generation is suppressed and further air penetration suppression performance is improved.

[0014] The rubber composition constituting the above-mentioned isolation rubber contains a rubber component of more than 20% by mass of isoprene-based rubber, and the rubber composition constituting the airtight layer preferably contains a rubber component of more than 70% by mass of butyl-based rubber.

[0015] Preferably, the statistical thickness specific surface area (STSA) (m 2 / g) of the above-mentioned recycled carbon black is greater than 37 and less than 77, and the ash content (% by mass) is greater than 11 and less than 27.

[0016] <Definition> "Normal state" means: a state without load of air filled with normal internal pressure and assembled on a normal rim.

[0017] "The dimensions of each part of the tire": Unless otherwise specified, the "dimensions of each part of the tire" appearing on the outer side of the tire are values specified in the normal state. On the other hand, for the "dimensions of each part of the tire" existing inside the tire and in the tire cross-section, for example, it is a value specified in a state where the cut tire piece holds the rim width of the normal rim after being cut by a plane including the tire rotation axis.

[0018] "The weight of the tire" is represented by G (kg). It refers to the weight of the tire alone without including the weight of the rim. On the other hand, when the inner cavity of the tire has a component composed of sponge or sealing material or a sensor component, etc., it is set to include the weight of these.

[0019] "Regular rim" means: in the standard system including the standards on which the tire is based, the rim specified by the standard for each tire. For example, it refers to the standard rim in the applicable sizes described in the "JATMA YEAR BOOK" of JATMA (Japan Automobile Tire Manufacturers Association), the "Measuring Rim" described in the "STANDARDS MANUAL" of ETRTO (The European Tyre and Rim Technical Organisation), and the "Design Rim" described in the "YEAR BOOK" of TRA (The Tire and Rim Association, Inc.). Refer to them in the order of JATMA, ETRTO, and TRA, and follow the standards of the applicable sizes if any when referring. In addition, for a tire not specified in the above standards, it means the rim with the smallest rim width among the rims with the minimum diameter that can assemble and maintain the internal pressure (i.e., no air leakage occurs between the rim and the tire).

[0020] "Regular internal pressure" means: in the standard system including the standards on which the tire is based, the air pressure specified by the standard for each tire. For example, it refers to the "maximum air pressure" of JATMA, the "INFLATION PRESSURE" of ETRTO, and the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" of TRA. Similar to the case of the regular rim, refer to them in the order of JATMA, ETRTO, and TRA, and follow the standards of the applicable sizes if any when referring. In addition, for a tire not specified in the above standards, it means the regular internal pressure (where it is 250 kPa or more) of other tire sizes (where the tire is specified in the standards) with the above regular rim as the standard rim. When there are multiple regular internal pressures of 250 kPa or more, it refers to the minimum value among them.

[0021] "Normal load" refers to the load specified for each tire in the standard system that includes the standard on which the tire is based. For example, it refers to the maximum value recorded in the "Maximum Load Capacity" of JATMA, the "LOAD CAPACITY" of ETRTO, and the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" of TRA. Similar to the case of the normal rim and normal internal pressure, it is referenced in the order of JATMA, ETRTO, and TRA, and when there are applicable dimensions during the reference, the standards thereof shall be followed. Meanwhile, for tires not specified in the above standards, the maximum load capacity W calculated separately shall be used as the normal load. L shall be set as the normal load.

[0022] "Maximum load capacity W" L " is calculated by the following formula. "V" is the virtual volume of the tire (mm 3 ), "Dt" is the outer diameter of the tire in the normal state (mm), "Ht" is the cross-sectional height of the tire in the tire diameter direction in the cross-section of the tire based on the plane including the tire rotation axis (mm), and "Wt" is the cross-sectional width of the tire in the normal state (mm). When the rim diameter of the tire is set as R, Ht can be obtained through (Dt - R) / 2. When there are patterns or letters on the tire sidewall, Wt is the value obtained after removing these. In addition, the maximum load capacity has the same meaning as the above normal load.

[0023]

Mathematical formula 1

[0024] "Recycled carbon black" refers to carbon black obtained by pulverizing used tire products containing carbon black and then firing the pulverized materials. When using the thermogravimetric method based on JIS K 6226-2:2003 and heating it in air to oxidize and burn it, the component that does not burn, that is, the mass (ash content) ratio of the ash is greater than 11% by mass of the carbon black. That is, the ratio of the mass (carbon amount) of the reduced part based on the above oxidation combustion is less than 89% by mass. Recycled carbon black is also called recycle carbon, recycle carbon black, and is sometimes represented by rCB.

[0025] "The thickness of the airtight layer" is the thickness in the tire radial direction at the equator in the cross-section of the tire based on the plane including the tire rotation axis. It is equivalent to Figure 1L. The "thickness of the airtight layer" is used as the average value of the values measured respectively in five tire cross-sections based on the plane containing the tire rotation axis, where the tire is rotated by 72 degrees successively. In addition, the measurement can be carried out by making a cross-section piece of the tire based on the plane containing the tire rotation axis and holding it in a state where the width between its beads corresponds to the normal rim width.

[0026] The "loss tangent of the rubber composition" is the loss tangent (tanδ) under each condition measured in the elongation mode using a dynamic viscoelasticity measuring device (for example, the EPLEXOR series manufactured by GABO). The sample used in the dynamic viscoelasticity measurement is a vulcanized rubber composition with a length of 20 mm, a width of 4 mm, and a thickness of 1 mm. When cutting out and making the sample from the tire, the length direction of the sample is made to coincide with the tire circumferential direction, and the thickness direction of the sample is made to coincide with the tire radial direction. When collecting the sample of the complex of the chafer and the airtight layer, the thickness of the airtight layer is appropriately adjusted so that the total thickness including the chafer is 1 mm and then cut out.

[0027] The "tanδ at 70°C" is the loss tangent (tanδ) measured under the conditions of a temperature of 70°C, a frequency of 10 Hz, an initial strain of 10%, a dynamic strain of ±1%, and a tensile mode.

[0028] <Measurement method> The "styrene content" is calculated by pyrolysis gas chromatography.

[0029] The "vinyl bonding amount (1,2-bonded butadiene unit amount)" is measured by infrared absorption spectrometry.

[0030] The "cis content (cis-1,4-bonded butadiene unit amount)" is measured by infrared absorption spectrometry.

[0031] The "ash content of the recycled carbon black" is measured by the thermogravimetric method of JIS K 6226-2:2003.

[0032] The "statistical thickness specific surface area (STSA) of the recycled carbon black" is the value obtained according to JIS K 6217-7:2017. In addition, the "nitrogen adsorption specific surface area (N2SA) of the recycled carbon black" is the value obtained according to JIS K 6217-2:2017.

[0033] The "average primary particle size of the carbon black" and the "average primary particle size of the recycled carbon black" are the values obtained by taking pictures of the particles with a transmission or scanning electron microscope and calculating the arithmetic average of the particle sizes of 400 particles. When the shape of the particle is spherical, the diameter of the sphere is set as the particle size; when it is other than spherical, the equivalent circle diameter calculated from the microscope image (the positive square root of {4×(particle area) / π}) is set as the particle size.

[0034] "Nitrogen adsorption specific surface area (N2SA) of silica" is a value measured by the BET method based on ASTM D3037-93.

[0035] "Air permeability coefficient" is a value measured based on Appendix 2 of JIS K 7126-1 (Gas Permeability Test Method Based on Gas Chromatography).

[0036] <Tire> Hereinafter, a tire according to an embodiment of the present invention will be described with appropriate reference to the accompanying drawings. However, the drawings are merely examples for illustration.

[0037] Figure 1 It is a schematic view showing a part (the upper right part of the cross-section) of the cross-section along the tire meridian in a tire according to an embodiment of the present invention. Figure 1 In this, the airtight layer 3 forms the inner surface of the tire 1 and maintains the inner pressure of the tire 1. The separator rubber 2 is adjacent to the outside in the tire rotation axis direction of the airtight layer, and the airtight layer is joined to other components such as the carcass via the separator rubber. The thickness of the airtight layer along the tire center line is represented by L.

[0038] The thickness L (mm) of the airtight layer on the tire equator plane is 1.5 mm or less, preferably 1.4 mm or less, more preferably 1.2 mm or less, and further preferably 1.1 mm or less. There is no particular lower limit, and for example, it can be 0.01 mm or more. It is considered that while the heat generation of the airtight layer is suppressed, the strain is also suppressed, and the air permeability resistance performance is improved.

[0039] In addition, since the rubber composition for the airtight layer according to the present invention is formed so as to become the inner cavity surface of the tire and serves as an airtight layer for reducing the air permeation amount and maintaining the tire inner pressure, excellent air permeability resistance is required. For the reason of obtaining excellent air permeability suppression of the required airtight layer, the air permeability coefficient of the rubber composition is less than 18×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), preferably 17×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, more preferably 16×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, further preferably 15×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, and further preferably 14.0×10 -11 cm 3 ·cm / (cm2 ·s·cmHg) or less. There is no particular lower limit, and for example, it can be 1.0×10 -13 cm 3 ·cm / (cm 2 ·s·cmHg) or more.

[0040] The air permeability coefficient can be changed by changing the types and contents of rubber components, fillers, resins, etc. in the rubber composition. Specifically, for example, if the amount of the filler is increased and its particle size is decreased, the air permeability coefficient can be reduced.

[0041] The loss tangent at 70°C (70°C tanδ) of the composite of the airtight layer and the separator rubber is 0.22 or less, preferably 0.21 or less, more preferably 0.20 or less. There is no particular lower limit, and for example, it can be 0.01 or more. It is considered that the heat generation inhibitory property is improved and the air permeability inhibitory property is improved. 70°C tanδ can be appropriately adjusted by the types and compounding amounts of the following polymer components, fillers, oils, resin components, etc. For example, by increasing the amount of the filler, decreasing its particle size, and decreasing the amounts of the vulcanizing agent and the vulcanization accelerator, it tends to increase 70°C tanδ, and by the opposite operation, it tends to decrease 70°C tanδ.

[0042] In addition, the loss tangent at 70°C of the rubber composition constituting the separator rubber is, for example, less than 0.185, preferably 0.18 or less, more preferably 0.17 or less, and further preferably 0.15 or less. It is considered that by setting it within this range, the air permeability inhibitory property is further improved.

[0043] In addition, the loss tangent at 70°C of the rubber composition constituting the airtight layer is, for example, less than 0.25, preferably 0.24 or less, more preferably 0.22 or less, and further preferably 0.21 or less. It is considered that by setting it within this range, the air permeability inhibitory property is further improved.

[0044] <Rubber composition> Hereinafter, the rubber composition for the separator rubber and the rubber composition for the airtight layer will be described.

[0045] [Rubber composition for separator rubber] Each component of the rubber composition for the separator rubber will be described. The rubber composition constituting the separator rubber contains recycled carbon black.

[0046] <Rubber component> The rubber composition constituting the spacer gum contains a rubber component of styrene butadiene rubber (SBR) containing isoprene rubber (IR rubber). In this case, the rubber component may contain rubber components other than IR rubber and SBR. In addition, the rubber component may also consist only of IR rubber and SBR. Each rubber that can constitute the rubber component is described as follows.

[0047] (Isoprene rubber) Examples of the isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. As NR, for example, common substances in the rubber industry such as SIR20, RSS#3, TSR20, SVR-L, etc. can be used. As IR, there is no particular limitation, for example, common substances in the rubber industry such as IR2200 can be used. Examples of the modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. Examples of the modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Examples of the modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. The isoprene rubber can be used alone or in combination of two or more.

[0048] The content rate of the IR rubber in 100% by mass of the rubber component is, for example, greater than 20% by mass, preferably greater than 30% by mass, more preferably greater than 40% by mass, and further preferably 50% by mass or more. On the other hand, this content is, for example, 100% by mass or less, preferably less than 90% by mass, more preferably less than 80% by mass.

[0049] (SBR) As for the styrene butadiene rubber (SBR), there is no particular limitation. For example, unmodified emulsion polymerization styrene butadiene rubber (E-SBR) or solution polymerization styrene butadiene rubber (S-SBR), modified emulsion polymerization styrene butadiene rubber (modified E-SBR) or modified solution polymerization styrene butadiene rubber (modified S-SBR) and other modified SBR obtained by modifying these can be cited. As the modified SBR, modified SBR modified at the terminal and / or main chain; modified SBR coupled with tin, silicon compounds, etc. (condensates, substances with branched structures, etc.) can be cited. In addition, as SBR, oil-extended substances with added extender oil to adjust flexibility and non-oil-extended substances without added extender oil can be cited, and any one of them can be used. As such SBR, for example, substances manufactured by JSR Corporation, Asahi Kasei Chemicals Corporation, Nippon Zeon Co., Ltd., ZS ELASTOMERS Co., Ltd., etc. can be used. SBR can be used alone or in combination of two or more.

[0050] The styrene content of the SBR is preferably more than 15% by mass, more preferably more than 20% by mass, and still more preferably more than 23% by mass. In addition, from the viewpoint of low fuel consumption, the styrene content is preferably less than 40% by mass, more preferably less than 30% by mass, and still more preferably less than 25% by mass. In addition, the styrene content of the SBR is a value calculated by 1 1H-NMR measurement.

[0051] The vinyl content (amount of 1,2-bonded butadiene units) of the SBR is preferably more than 10% by mass, more preferably more than 15% by mass. In addition, the vinyl content is preferably less than 80% by mass, preferably less than 50% by mass, and more preferably less than 30% by mass. In addition, the vinyl content of the SBR is a value measured by infrared absorption spectroscopy.

[0052] The content rate of the SBR-based rubber in 100% by mass of the rubber component is, for example, more than 5% by mass, preferably more than 10% by mass, more preferably more than 20% by mass, and still more preferably more than 25% by mass. On the other hand, this content is, for example, 100% by mass or less, preferably less than 90% by mass, and more preferably less than 80% by mass.

[0053] In addition, the total content of the IR-based rubber and the SBR in 100% by mass of the rubber component is preferably more than 80% by mass, more preferably more than 90% by mass, still more preferably more than 95% by mass, and may also be 100% by mass.

[0054] (Other rubbers) Other rubbers that can be used other than the above are not particularly limited, and rubbers used in the tire field and the like can be used. For example, diene rubbers such as butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and styrene-isoprene-butadiene copolymer rubber (SIBR) can be cited. Other rubbers can be used alone or in combination of two or more.

[0055] (BR) BR is not particularly limited, and examples thereof include BR with a high cis content, BR containing 1,2-syndiotactic polybutadiene crystals (BR containing SPB), butadiene rubber synthesized using a rare earth element catalyst (rare earth BR), tin-modified butadiene rubber modified by a tin compound (tin-modified BR), and other modified butadiene rubbers (modified BR) that are common in the tire industry. As commercially available products, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used. The modified BR may be any BR having a functional group that interacts with a filler such as silica, and examples thereof include terminal-modified BR in which at least one terminal of the BR is modified with a compound (modifier) ​​having the above functional group (terminal-modified BR having the above functional group at the terminal), main chain-modified BR having the above functional group on the main chain, main chain terminal-modified BR having the above functional group on the main chain and the terminal (for example, main chain terminal-modified BR having the above functional group on the main chain and at least one terminal modified with the above modifier), and terminal-modified BR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and into which a hydroxyl group or epoxy group is introduced. As the above functional groups, for example, amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazolyl, urea, ether, carbonyl, oxycarbonyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imido, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxy, epoxy, etc. can be cited. In addition, these functional groups may also have substituents. Among them, amino (preferably an amino group in which the hydrogen atom possessed by the amino group is substituted by an alkyl group having 1 to 6 carbon atoms), alkoxy (preferably an alkoxy group having 1 to 6 carbon atoms), alkoxysilyl (preferably an alkoxysilyl group having 1 to 6 carbon atoms).

[0056] The cis content of BR is preferably greater than 90% by mass, more preferably greater than 93% by mass, further preferably greater than 95% by mass, and further preferably 97% by mass or more. The cis content of BR can be measured by infrared absorption spectroscopic analysis.

[0057] As BR, for example, products of UBE Co., Ltd., JSR Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd., etc. can be used. BR may be used alone or in combination of two or more.

[0058] (Rubber components synthesized from recycled / biomass-derived raw materials) The monomers that are the constituent units of synthetic rubbers such as IR, SBR, and BR can be substances derived from underground resources such as petroleum and natural gas, or substances recovered from rubber products such as tires or non-rubber products such as polystyrene. As the monomers obtained by recovery (recovered monomers), there is no particular limitation, and examples include recovered polyisoprene, recovered butadiene, recovered aromatic vinyl compounds, etc. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above-mentioned aromatic vinyl compound, there is no particular limitation, and examples include styrene, etc. Among them, it is preferable to use recovered polyisoprene (recovered isoprene), recovered butadiene, and / or recovered styrene (recovered styrene) as raw materials.

[0059] As the method for producing the recovered monomer, there is no particular limitation. For example, it can be cited as being synthesized from recovered naphtha obtained by cracking rubber products such as tires. In addition, as the method for producing the recovered naphtha, there is no particular limitation. For example, rubber products such as tires can be cracked under high temperature and high pressure, or cracked by microwave, or extracted after mechanical pulverization.

[0060] Furthermore, the monomers that are the constituent units of polymers such as IR, SBR, and BR can also be substances derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. As the biomass, there is no particular limitation. For example, it can be cited as including agricultural and forestry products or sugars, wood chips, plant residues after obtaining useful components, ethanol of plants, biomass naphtha, etc. As the monomers derived from biomass (biomass monomers), there is no particular limitation, and examples include butadiene derived from biomass, aromatic vinyl compounds derived from biomass, etc. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above-mentioned aromatic vinyl compound, there is no particular limitation, and examples include styrene, etc. In addition, the method for producing the monomers derived from biomass is not particularly limited. For example, substances obtained by biological and / or chemical and / or physical conversion of animals and plants can be cited. As the biological conversion, fermentation based on microorganisms is representative. As the chemical and / or physical conversion, conversions based on catalysts, conversions based on high heat, conversions based on high pressure, conversions based on electromagnetic waves, conversions based on supercritical fluids, and combinations thereof can be cited.

[0061] As the polymer synthesized from biomass monomer components (biomass polymer), there is no particular limitation, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl compound, and the like. As the above-mentioned aromatic vinyl / butadiene copolymer, for example, styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene can be mentioned.

[0062] Whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D6866-10.

[0063] pMC refers to: the 14 C concentration of the sample relative to that of the 14 modern standard reference of C, which is a value used as an index representing the biomass ratio of a compound. The meaning of this value will be described below.

[0064] In 1 mole (6.02×10 23 ), there is about one trillionth of the ordinary carbon atoms, that is, about 6.02×10 11 atoms 14 of 14 C. The half-life of 14 C is 5730 years, and 14 C decreases regularly. Therefore, it can be considered that after carbon dioxide in the atmosphere is absorbed and fixed by plants, etc., in fossil fuels such as coal, oil, and natural gas that have experienced more than 226,000 years, all of the 14 C elements contained therein at the time of initial fixation have decayed. Therefore, in the 21st century today, fossil fuels such as coal, oil, and natural gas do not contain any 14 C elements at all. Therefore, chemical substances produced using these fossil fuels as raw materials also do not contain any

[0065] On the other hand, 14 C is continuously generated by nuclear reactions in the atmosphere through cosmic rays. Therefore, 14 the decrease of 14 C due to radioactive decay and the generation due to nuclear reactions reach equilibrium, and in the atmospheric environment of the earth, 14 the -12 C concentration of substances in biomass resources derived from the material cycle is about 1×10

[0066] Generally, the 14 C is measured as described below. Using accelerator mass spectrometry based on a tandem accelerator, the 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 C) is measured. When measuring, as the standard modern carbon for the reference of the 14 C concentration, the 14 C concentration in the circulating carbon in nature in 1950 is adopted. As a specific reference material, the oxalic acid reference material provided by NIST (National Institute of Standards and Technology) is used. Classify the specific radioactivity of carbon in this oxalic acid (the radioactivity of 14 C per 1 g of carbon) according to each carbon isotope, correct 13 C to a fixed value, and use the value after applying the decay correction from 1950 AD to the measurement date as the standard 14 C concentration value (100%). The ratio of the value of the actually measured sample to this value is the pMC value.

[0067] Therefore, if the rubber is 100% made of biomass-derived substances, although there are regional differences, etc., since it is mostly not 100 under normal conditions now, it is expected to show a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, a value of about 0 pMC (for example, 0.3 pMC) is shown. This value corresponds to a biomass ratio of 0%.

[0068] In summary, it is preferable in terms of environmental protection to use materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in the rubber composition.

[0069] <Filler> The rubber composition for an insulating rubber according to an embodiment of the present invention contains a filler containing recycled carbon black (rCB). In addition, the filler may also contain carbon black, silica, and other reinforcing fillers used in the tire industry. Preferably, the filler contains recycled carbon black and carbon black other than recycled carbon black. When the filler contains silica, a silane coupling agent may be further contained.

[0070] (Recycled Carbon Black) In the present invention, recycled carbon black refers to carbon black obtained by the thermal cracking process of used products such as tires containing carbon black. When oxidized and burned by heating in air using the thermogravimetric method based on JIS K 6226-2:2003, the proportion of the non-combustible component, i.e., the mass of ash (ash content), is greater than 11% by mass of the carbon black. The ash content of the recycled carbon black is preferably 13% by mass or more, more preferably 15% by mass or more, further preferably 16% by mass or more, and still further preferably 17% by mass or more. In addition, the ash content is preferably less than 27% by mass, more preferably less than 26% by mass, and further preferably less than 25% by mass.

[0071] Recycled carbon black can be obtained by the thermal cracking process of used pneumatic tires. For example, European Patent Application Publication No. 3427975 describes that in "Rubber Chemistry and Technology", Vol. 85, No. 3, pages 408-449 (2012), especially pages 438, 440, and 442, it is mentioned that thermal cracking of organic materials is carried out at 550-800 °C after removing oxygen, or by vacuum thermal cracking at a relatively low temperature (

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

[0004] of Patent No. 6856781, usually lacks functional groups on its surface (comparison of the surface morphology and chemistry of thermal cracking carbon black and commercially available carbon black, Powder Technology 160 (2005) 190-193). It is considered that, like this, since the recycled carbon black has fewer surface functional groups, the interaction with the rubber component becomes smaller, and the heat generation based on the friction with the rubber decreases.

[0072] Recycled carbon black can be carbon black lacking functional groups on its surface, or it can also be carbon black that has been treated to make its surface contain functional groups. The treatment to make the surface of recycled carbon black contain functional groups can be carried out by conventional methods. For example, in European Patent Application Publication No. 3173251, carbon black obtained by the thermal cracking process is treated with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl groups and / or carboxyl groups on its surface. In addition, in Patent No. 6856781, carbon black obtained by the thermal cracking process is treated with an amino acid compound containing at least one mercapto group or disulfide group to obtain carbon black with an activated surface. The recycled carbon black involved in this embodiment includes such carbon black treated to make its surface contain functional groups.

[0073] The average primary particle diameter of the recycled carbon black is preferably 20 nm or more, more preferably 25 nm or more, still more preferably 30 nm or more, and particularly preferably 35 nm or more. It is considered that by setting the average primary particle diameter of the carbon black within the above range, the rubber molecules bound by the carbon black are suppressed to the minimum and can move flexibly, so that the polymer molecular chains can also relieve the input stress. On the other hand, the average primary particle diameter is preferably 90 nm or less, more preferably 75 nm or less, and still more preferably 60 nm or less. In addition, the average primary particle diameter of the carbon black is measured by the above-mentioned measuring method.

[0074] The nitrogen adsorption specific surface area (N2SA) of the recycled carbon black is not particularly limited. From the viewpoint of obtaining sufficient reinforcing properties and good abrasion resistance, it is preferably greater than 30 m 2 / g, more preferably greater than 40 m 2 / g, still more preferably greater than 50 m 2 / g, still more preferably greater than 60 m 2 / g, still more preferably greater than 70 m 2 / g. In addition, from the viewpoints of excellent dispersibility and low heat generation, the N2SA is preferably less than 300 m 2 / g, more preferably less than 200 m 2 / g, still more preferably less than 150 m 2 / g, still more preferably less than 120 m 2 / g, still more preferably less than 110 m 2 / g, still more preferably less than 100 m 2 / g, still more preferably less than 90 m 2 / g. In addition, the N2SA of the recycled carbon black in this specification is a value measured based on JIS K 6217-2:2017.

[0075] The statistical thickness specific surface area (STSA) of the recycled carbon black is not particularly limited. From the viewpoint of obtaining sufficient reinforcing properties and good abrasion resistance, it is preferably greater than 37 m 2 / g, more preferably greater than 40 m 2 / g, still more preferably greater than 45 m 2 / g. In addition, from the viewpoints of excellent dispersibility and low heat generation, the STSA is preferably less than 77 m 2 / g, more preferably less than 75 m 2 / g, still more preferably less than 73 m 2 / g. In addition, the STSA of the recycled carbon black in this specification is a value measured based on JIS K6217-7:2017.

[0076] From the viewpoint of reinforcement, the content of recycled carbon black is, for example, more than 10 parts by mass, preferably more than 20 parts by mass, more preferably 30 parts by mass or more, and still more preferably more than 50 parts by mass with respect to 100 parts by mass of the rubber component.

[0077] (carbon black other than rCB) The carbon black other than recycled carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw material of the carbon black may be a biomass material such as lignin or vegetable oil, or may be a pyrolysis oil obtained by pyrolyzing waste tires. In addition, the manufacturing method of the carbon black may be a combustion-based method such as a furnace method, a method based on hydrothermal carbonization (HTC), or a method based on thermal pyrolysis of methane derived from a thermal cracking carbon black method. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbia Carbon Company, etc. can be used. These carbon blacks can be used alone or in combination of two or more.

[0078] The average primary particle diameter of the carbon black is preferably 20 nm or more, more preferably 25 nm or more, still more preferably 30 nm or more, and particularly preferably 35 nm or more. It is considered that by setting the average primary particle diameter of the carbon black within the above range, the rubber molecules bound by the carbon black are suppressed to a minimum and can move flexibly, so that the polymer molecular chains can also relieve the input stress. On the other hand, the average primary particle diameter is preferably 90 nm or less, more preferably 75 nm or less, still more preferably 60 nm or less. In addition, the average primary particle diameter of the carbon black is measured by the above measurement method.

[0079] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited. From the viewpoint of obtaining sufficient reinforcement and good abrasion resistance, it is preferably more than 30 m 2 / g, more preferably more than 40 m 2 / g, still more preferably more than 50 m 2 / g, still more preferably more than 60 m 2 / g, still more preferably more than 70 m 2 / g. In addition, from the viewpoints of excellent dispersibility and low heat generation, the N2SA is preferably less than 300 m 2 / g, more preferably less than 200 m 2 / g, still more preferably less than 150 m 2 / g, still more preferably less than 120 m 2 / g, still more preferably less than 110 m2 / g, and more preferably less than 100 m 2 / g, and more preferably less than 90 m 2 / g. In addition, the N2SA of the carbon black in this specification is a value measured based on JIS K 6217-2:2017.

[0080] The statistical thickness specific surface area (STSA) of the carbon black is not particularly limited. From the viewpoint of obtaining sufficient reinforcing properties and good abrasion resistance, it is preferably greater than 37 m 2 / g, more preferably greater than 40 m 2 / g, and more preferably greater than 45 m 2 / g. In addition, from the viewpoints of excellent dispersibility and low heat generation, the STSA is preferably less than 77 m 2 / g, more preferably less than 75 m 2 / g, and more preferably less than 73 m 2 / g. In addition, the STSA of the carbon black in this specification is a value measured based on JIS K 6217-7:2017.

[0081] (Content of carbon black) When carbon black is contained, the content of carbon black is, for example, greater than 10 parts by mass, preferably greater than 20 parts by mass, and more preferably 30 parts by mass or more, relative to 100 parts by mass of the rubber component. The total content of carbon black containing recycled carbon black is, for example, greater than 20 parts by mass, preferably greater than 30 parts by mass, more preferably greater than 40 parts by mass, further preferably greater than 50 parts by mass, and further preferably 60 parts by mass or more, relative to 100 parts by mass of the rubber component. On the other hand, the total content is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and further preferably less than 80 parts by mass. When the content of carbon black is within the above range, sufficient reinforcing properties can be obtained, the dispersion in the rubber is good, and it tends to obtain sufficient rubber strength and crack growth resistance.

[0082] (Silica) There is no particular limitation on the silica. For example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), etc., which are commonly used in the tire industry, can be used. There is no particular limitation on the raw material of the silica. For example, it can be a raw material derived from minerals such as quartz, or a raw material derived from organisms such as rice husks (for example, silica using biomass materials such as rice husks as raw materials), and silica recovered from products containing silica can also be used. Among them, due to the large number of silanol groups, hydrous silica prepared by a wet method is preferred. These silicas can be used alone or in combination of two or more.

[0083] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks with a sodium hydroxide solution, and reacting the silicate with sulfuric acid in the same manner as conventional wet silica to produce a silica precipitate, which is then filtered, washed with water, dried, and pulverized.

[0084] Silica recovered from products containing silica, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, diatomaceous earth and other filter materials can be used. In addition, the recovery method is not particularly limited, and thermal cracking, electromagnetic wave cracking and the like can be cited. Among them, silica recovered from electronic components such as semiconductors or tires is preferred.

[0085] If silicon dioxide is crystallized, it will not dissolve in water, and the silicic acid as a component cannot be used. By controlling the combustion temperature and combustion time, the crystallization of silicon dioxide in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Online Journal B (Akita Prefectural University ウェブジャーナルB) / 2019, vol. 6, p. 216-222, etc.).

[0086] Amorphous silica extracted from rice husks and commercially available products such as Wilmar can be used.

[0087] The nitrogen adsorption specific surface area (N2SA) of silicon dioxide is preferably greater than 50 m 2 / g, more preferably greater than 100m 2 / g, more preferably greater than 150m 2 / g, particularly preferably greater than 170m 2 / g. In addition, the upper limit of N2SA of silica is not particularly limited, but is preferably less than 350 m 2 / g, more preferably less than 250m 2 / g, more preferably less than 200m 2 / g. By setting it within the above range, the cut resistance tends to be improved. In addition, the N2SA of silica is a value measured by the BET method based on ASTM D3037-93.

[0088] (Silicon dioxide content) When silica is contained, the content relative to 100 parts by mass of the rubber component is not particularly limited, but from the viewpoint of ensuring low fuel consumption and ride comfort performance, it is preferably greater than 1 part by mass, preferably greater than 5 parts by mass, more preferably greater than 10 parts by mass, and further preferably greater than 20 parts by mass. In addition, from the viewpoint of dispersibility and processability of silica, the content is preferably less than 150 parts by mass, more preferably less than 100 parts by mass, further preferably less than 50 parts by mass, and further preferably less than 30 parts by mass.

[0089] (Silane coupling agent) When using silica as a filler, it is preferably further contained with a silane coupling agent. There is no particular limitation on the silane coupling agent. For example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide and other sulfide series; 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT, NXT-Z manufactured by Momentive and other mercapto series; vinyltriethoxysilane, vinyltrimethoxysilane and other vinyl series; 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and other amino series; γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and other glycidoxy series, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane and other nitro series; 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane and other chloro series, etc. As commercially available products, products of Evonik Degussa AG, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Toray Dow Corning Co., Ltd., etc. can be used. These can be used alone or in combination of two or more.

[0090] (Content of silane coupling agent) When containing a silane coupling agent, the content of the silane coupling agent is preferably more than 1 part by mass, more preferably more than 3 parts by mass, further preferably more than 5 parts by mass, and further preferably more than 7 parts by mass with respect to 100 parts by mass of silica. On the other hand, the content is preferably less than 20 parts by mass, more preferably less than 18 parts by mass, further preferably less than 16 parts by mass, and further preferably less than 14 parts by mass. By setting it within the above range, the dispersibility of silica tends to be improved.

[0091] (Other fillers) As other fillers, there is no particular limitation, and materials known in the field of the tire industry can be used. For example, inorganic fillers such as calcium carbonate, talc, bauxite, clay, aluminum hydroxide, alumina, mica, etc. can be cited. These can be used alone or in combination of two or more.

[0092] <Other compounding agents> In the rubber composition, in addition to the rubber component and the filler, compounding agents commonly used in the conventional tire industry can be appropriately contained. For example, plasticizers, processing aids, vulcanized rubber particles, waxes, stearic acid, zinc oxide, anti-aging agents, vulcanizing agents, vulcanization accelerators, etc.

[0093] (Plasticizer) A plasticizer is a material that imparts plasticity to the rubber component, and is a concept including both plasticizers that are liquid (in a liquid state) at 25°C and plasticizers that are solid at 25°C. Examples of plasticizers include resin components, oils, liquid polymers, ester-based plasticizers, etc. These plasticizers can be substances derived from petroleum, substances derived from biomass, and substances derived from naphtha recovered from rubber products and non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by thermally cracking and extracting used tires and products containing various components can also be used as plasticizers. These plasticizers can be used alone or in combination of two or more.

[0094] 《Oil》 As the oil, for example, mineral oil, vegetable oil, animal oil, etc. can be cited. In addition, from the perspective of life cycle assessment, oils refined from waste oils used in rubber mixers or engines and waste cooking oils used in restaurants can also be used. The oil can be used alone or in combination of two or more.

[0095] In this specification, mineral oil refers to: oils derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffin-based oils (mineral oil), naphthenic oils, aromatic oils, etc. Specific examples of mineral oil include, for example, MES (Mild Extract Solvate), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. In addition, due to environmental measures, oils with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of the oils with a low PCA content include MES, TDAE, and heavy naphthenic oils.

[0096] In this specification, vegetable oils refer to: for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc. Further, as vegetable oils, refined oils (such as salad oil) obtained by refining the above oils, transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidation-polymerized oils obtained by oxidizing the above oils, waste edible oils obtained by recovering the oils used as edible oils, etc. can also be listed. In addition, vegetable oils can be liquid or solid at room temperature (25°C). These vegetable oils can be used alone or in combination of two or more.

[0097] The vegetable oil involved in this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. In addition, 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 acylglycerol, and it can be any one of 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, and triacylglycerol. Further, acylglycerol can be a monomer, a dimer, or a polymer of trimer or higher. In addition, acylglycerol dimers or higher can be obtained by thermal polymerization, oxidation polymerization, etc. In addition, acylglycerol can be liquid or solid at room temperature (25°C).

[0098] As a method for confirming the presence of acylglycerol in the rubber composition, there is no particular limitation, and it can be confirmed by 1 1H-NMR measurement. For example, the rubber composition compounded with triacylglycerol is immersed in deuterated chloroform at room temperature (25 °C) for 24 hours. After removing the rubber composition, 1H-NMR is measured at room temperature. 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm can be observed. It is speculated that these signals are from the hydrogen atoms bonded to the carbon atoms adjacent to the oxygen atom of the ester group. In addition, "around" in this paragraph means a range of ±0.10 ppm.

[0099] As the above fatty acid, there is no particular limitation, and it can be an unsaturated fatty acid or a saturated fatty acid. As the unsaturated fatty acid, monounsaturated fatty acids such as oleic acid or polyunsaturated fatty acids such as linoleic acid and linolenic acid can be cited. In addition, as the saturated fatty acid, butyric acid, lauric acid, etc. can be cited.

[0100] Among them, as the above fatty acid, it is preferably a fatty acid with fewer double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As such a vegetable oil containing a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid can be used, or a modified vegetable oil such as transesterified oil can also be used. In addition, in order to produce such a vegetable oil containing a fatty acid, plants can also be improved by variety improvement, genetic modification, etc.

[0101] As the vegetable oil, for example, commercially available substances from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0102] The oil content relative to 100 parts by mass of the rubber component is preferably greater than 1 part by mass, more preferably greater than 3 parts by mass, and further preferably greater than 5 parts by mass. In addition, this content is preferably less than 20 parts by mass, more preferably less than 15 parts by mass, and further preferably less than 10 parts by mass. In addition, the oil content also includes the amount of oil contained as extender oil in the rubber component and the amount of oil contained in other components such as sulfur.

[0103] "Liquid Polymer" A liquid polymer refers to a polymer that is in a liquid state at normal temperature (25 °C). For example, liquid diene polymers can be cited. As liquid diene polymers, liquid styrene-butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), liquid styrene-isoprene copolymers (liquid SIR), etc. can be cited. The liquid diene polymer preferably has a number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) greater than 1000, more preferably greater than 3000. On the other hand, the Mn is preferably less than 100,000, more preferably less than 15,000. The Mn of the liquid polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC). As liquid diene polymers, for example, products of Sartomer Company, Kuraray Co., Ltd., etc. can be used. The liquid polymer can be used alone or in combination of two or more.

[0104] (Resin) The rubber composition preferably contains a resin among the above other compounding agents. As the resin, there is no particular limitation, and resins commonly used in the tire industry can be used. For example, aromatic vinyl resins, dicyclopentadiene resins, C9 resins, C5 resins, C5-C9 resins, terpene resins, rosin resins, phenolic resins, etc. can be cited. Among them, petroleum resins, aromatic vinyl resins, dicyclopentadiene resins, C9 resins, and terpene resins are preferred. The resin can be used alone or in combination of two or more.

[0105] 《C9 Resin》 "C9 resin" refers to a resin obtained by polymerizing C9 fractions, which can be a resin obtained by polymerizing C9 fractions alone or a copolymer obtained by copolymerizing C9 fractions with other components. For example, a resin obtained by copolymerizing dicyclopentadiene (DCPD) with C9 fractions is called DCPD / C9 resin. In addition, it can also be their hydrogenated products or modified products. As C9 fractions, for example, at least one petroleum fraction having 8 to 10 carbon atoms selected from vinyltoluene, alkylstyrene, coumarone, indene, methylindene, dicyclopentadiene, etc. can be cited. As specific examples of C9 resins, for example, coumarone-indene resins, coumarone resins, indene resins, etc. can be cited. The resin can be used alone or in combination of two or more.

[0106] 《C5 Resin》 "C5 resin" refers to: a resin obtained by polymerizing C5 fractions other than dicyclopentadiene, or it can also be their hydrogenated products or modified products. As C5 fractions other than dicyclopentadiene, for example, at least one petroleum fraction equivalent to 4 to 5 carbon atoms selected from cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, pentadiene, etc. can be cited. This resin can be used alone or in combination of two or more.

[0107] "C5C9 Resin" "C5C9 resin" refers to: a resin obtained by copolymerizing the above C5 fraction and the above C9 fraction, or it can also be their hydrogenated products or modified products. As C5C9 petroleum resins, for example, commercially available substances such as those from Tosoh Corporation and LUHUA Company can be used. This resin can be used alone or in combination of two or more.

[0108] "Dicyclopentadiene Resin" "Dicyclopentadiene resin" refers to: a resin containing dicyclopentadiene (DCPD) as the monomer component with the largest content, or it can also be their hydrogenated products or modified products. As dicyclopentadiene resins, for example, DCPD / C9 resins obtained by copolymerizing dicyclopentadiene and the above C9 fraction can be cited, and DCPD / C9 resins are preferred. As DCPD resins, for example, commercially available substances from ExxonMobil Corporation, ENEOS Corporation, Nippon Zeon Co., Ltd., Maruzen Petrochemical Co., Ltd., etc. can be used. This resin can be used alone or in combination of two or more.

[0109] "Aromatic Vinyl Resin" "Aromatic vinyl resin" refers to: a resin containing at least one aromatic vinyl compound selected from styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, etc. as the monomer component with the largest content, preferably a resin containing 50 mol% or more, or it can also be their hydrogenated products or modified products. As aromatic vinyl resins, due to reasons such as economy, easy processing, and excellent heat generation properties, homopolymers of α-methylstyrene or styrene or copolymers of α-methylstyrene and styrene are preferred, and copolymers of α-methylstyrene and styrene are more preferred. As aromatic vinyl resins, for example, commercially available substances from Kraton Corporation, Eastman Chemical Company, Mitsui Chemicals, Inc., etc. can be used. This resin can be used alone or in combination of two or more.

[0110] "Terpene Resin" "Terpene resin" refers to: a resin containing at least one terpene compound selected from α-pinene, β-pinene, limonene, dipentene, etc. as the monomer component with the highest content, preferably containing 50 mol% or more, and may also be their hydrogenated products or modified products. As specific examples of terpene resins, for example, polyterpene resins containing only one or more of the above terpene compounds as monomer components; aromatic modified terpene resins containing the above terpene compounds and aromatic compounds as monomer components; terpene phenol resins containing the above terpene compounds and phenolic compounds as monomer components, etc. As the aromatic compounds that are monomer components of aromatic modified terpene resins, for example, at least one selected from styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. can be cited. As the phenolic compounds that are monomer components of terpene phenol resins, for example, at least one selected from phenol, bisphenol A, cresol, xylenol, etc. can be cited. This resin can be used alone or in combination of two or more kinds.

[0111] 《Resin of Rosin Series》 As a resin of rosin series, it refers to a resin containing at least one rosin acid compound selected from abietic acid, neoabietic acid, palustric acid, isopimaric acid, etc., preferably as the monomer component with the highest content, more preferably containing 50 mol% or more, and may also be their hydrogenated products or modified products. There is no particular limitation for the resin of rosin series. For example, natural resin rosin, rosin modified resins obtained by hydrogenating, disproportionating, dimerizing, esterifying it, etc. can be cited. This resin can be used alone or in combination of two or more kinds.

[0112] 《Phenolic Resin》 As a phenolic resin, it refers to a resin containing phenolic compounds such as phenol and cresol as the monomer component with the highest content, preferably containing 50 mol% or more. There is no particular limitation for the phenolic resin. Phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, oil-modified phenol formaldehyde resin, etc. can be cited. This resin can be used alone or in combination of two or more kinds.

[0113] When containing resin, the content relative to 100 parts by mass of the rubber component is preferably greater than 2 parts by mass, more preferably greater than 3 parts by mass, and further preferably greater than 4 parts by mass. On the other hand, this content is preferably less than 20 parts by mass, more preferably less than 15 parts by mass, and further preferably less than 10 parts by mass.

[0114] 《Ester Plasticizer》 As ester plasticizers, for example, dibutyl adipate (DBA), diisobutyl adipate (DIBA), dioctyl adipate (DOA), bis(2-ethylhexyl) azelate (DOZ), dibutyl sebacate (DBS), diisononyl adipate (DINA), diethyl phthalate (DEP), dioctyl phthalate (DOP), dilauryl 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), trixylenyl phosphate (TXP), etc. can be cited. The ester plasticizers can be used alone or in combination of two or more.

[0115] (Antioxidant) As the antioxidant, there is no particular limitation, and examples include naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylxylenyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD), etc.; quinoline antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bis-, tri-, and polyphenol antioxidants such as tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine antioxidants and quinoline antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Co., etc. can be used. The antioxidant can be used alone or in combination of two or more.

[0116] When the antioxidant is contained, the content is preferably more than 0.5 parts by mass, more preferably more than 0.8 parts by mass, and further preferably more than 1.0 parts by mass with respect to 100 parts by mass of the rubber component. On the other hand, the content is preferably less than 7.0 parts by mass, more preferably less than 5.0 parts by mass, and further preferably 3.0 parts by mass or less.

[0117] (Vulcanized rubber particles) Vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder specified in JIS K 6316:2017 can be used, etc. From the viewpoints of environmental concerns and cost, recycled rubber powder made from crushed waste tires, etc. is preferred. These can be used alone or in combination of two or more.

[0118] As the vulcanized rubber particles, there is no particular limitation, and they can be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0119] As commercially available products of vulcanized rubber, for example, products of Lehigh Company, Murakami Rubber Industry Co., Ltd., etc. can be used.

[0120] (Processing aid) As processing aids, for example, fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, mixtures of fatty acid metal salts and amide esters, mixtures of fatty acid metal salts and fatty acid amides, etc. can be cited. These processing aids can be used alone or in combination of two or more. As processing aids, for example, substances commercially available from companies such as Schill+Seilacher Company and Performance-Additives Company can be used.

[0121] From the viewpoint of exerting the improvement effect of processability, when containing processing aids, the content relative to 100 parts by mass of the rubber component is preferably greater than 0.5 part by mass, more preferably greater than 1 part by mass, and further preferably greater than 1.5 parts by mass. In addition, from the viewpoints of abrasion resistance and breaking strength, it is preferably less than 10 parts by mass, more preferably less than 8.0 parts by mass, and further preferably less than 5.0 parts by mass.

[0122] (Wax) As the wax, there is no particular limitation, and any one of the substances commonly used in the tire industry can be preferably used. For example, mineral waxes, plant-derived waxes, etc. can be cited. 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 them, mineral waxes are preferred. As plant-derived waxes, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As mineral waxes, for example, paraffin wax, microcrystalline wax, selected special waxes of these, etc. are cited, and paraffin wax is preferred. In addition, the wax involved in this embodiment is set to be wax without stearic acid. Waxes can be used alone or in combination of two or more. For example, substances commercially available from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Company, etc. can be used as the wax.

[0123] When wax is contained, its content is preferably more than 0.3 parts by mass, more preferably more than 0.7 parts by mass, and still more preferably more than 1.0 parts by mass with respect to 100 parts by mass of the rubber component. On the other hand, the content is preferably less than 4.0 parts by mass, more preferably less than 3.0 parts by mass, and still more preferably less than 2.5 parts by mass.

[0124] (Stearic acid) From the viewpoint of processability, when stearic acid is contained, its content is preferably more than 0.5 parts by mass, more preferably more than 0.7 parts by mass, and still more preferably 1.0 parts by mass or more with respect to 100 parts by mass of the rubber component. On the other hand, from the viewpoint of vulcanization rate, the content is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, and still more preferably less than 3 parts by mass.

[0125] (Zinc oxide) From the viewpoint of processability, when zinc oxide is contained, its content is preferably more than 0.5 parts by mass, more preferably more than 0.7 parts by mass, and still more preferably more than 1 part by mass with respect to 100 parts by mass of the rubber component. On the other hand, from the viewpoint of abrasion resistance, the content is preferably 10 parts by mass or less, more preferably less than 7 parts by mass, and still more preferably 5 parts by mass or less.

[0126] (Vulcanizing agent) As the vulcanizing agent, there is no particular limitation, and known vulcanizing agents can be used. For example, organic peroxides, sulfur-based vulcanizing agents, resin vulcanizing agents, metal oxides such as magnesium oxide, etc. can be cited. Among them, sulfur-based vulcanizing agents are preferred. As the sulfur-based vulcanizing agent, for example, sulfur donors such as sulfur and morpholine disulfide can be used. Among them, sulfur is preferably used. The vulcanizing agent can be used alone or in combination of two or more.

[0127] As sulfur, powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur (oil-treated sulfur, special sulfur treated with a dispersant, masterbatch-type sulfur, etc.), insoluble sulfur (oil-treated insoluble sulfur, etc.) can be cited, and any one of them can be preferably used. Among them, powdered sulfur is preferred. Sulfur, for example, can be a substance manufactured and sold by Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Ltd., Nihon Kanryu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc.

[0128] As the vulcanizing agent, known organic crosslinking agents can also be used. As the organic crosslinking agent, there is no particular limitation as long as it is a substance that can form crosslinking chains other than polysulfide bonds. For example, alkylphenol / sulfur chloride condensates, sodium 1,6-hexamethylenedithiocarbamate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyl disulfide) hexane, dicumyl peroxide, etc. can be cited, and 1,6-bis(N,N'-dibenzylthiocarbamoyl disulfide) hexane is preferred. These organic crosslinking agents can use commercially available substances from companies such as Tago Chemical Industry Co., Ltd., Lanxess Co., Ltd., and Flexis Co., Ltd.

[0129] When a vulcanizing agent is contained, the content relative to 100 parts by mass of the rubber component is preferably greater than 0.4 part by mass, more preferably greater than 0.5 part by mass, further preferably greater than 1.0 part by mass, and further preferably greater than 1.5 part by mass. On the other hand, the content is preferably less than 6.0 parts by mass, more preferably 5.0 parts by mass or less, and further preferably less than 4.0 parts by mass. When the content of the vulcanizing agent is within the above range, it tends to obtain a suitable reinforcing effect. In addition, when the vulcanizing agent contains components other than sulfur, such as oil-treated sulfur, the content of the vulcanizing agent represents the content of the sulfur component itself.

[0130] (Vulcanization accelerator) There is no particular limitation on the vulcanization accelerator, and known vulcanization accelerators can be used. For example, sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamate-based, aldehyde-amine-based or aldehyde-ammonia-based, imidazoline-based, or xanthate-based vulcanization accelerators can be cited. Among them, sulfenamide-based, thiuram-based, and guanidine-based are preferred, and sulfenamide-based is more preferred. The vulcanization accelerator, for example, can use substances manufactured and sold by Ouchi Shinsei Chemical Industry Co., Ltd., Sanshin Chemical Industry Co., Ltd., etc. These vulcanization accelerators can be used alone or in combination of two or more.

[0131] As the sulfenamide-based vulcanization accelerator, for example, N-tert-butyl-2-benzothiazole sulfenamide (TBBS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N'-dicyclohexyl-2-benzothiazole sulfenamide (DZ), etc. can be cited. As the thiuram-based vulcanization accelerator, for example, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetrabenzylthiuram disulfide (TBzTD), etc. can be cited. As the guanidine-based vulcanization accelerator, for example, 1,3-diphenylguanidine (DPG), di-o-tolylguanidine, o-tolylbiguanide, etc. can be cited.

[0132] The content of the vulcanization accelerator relative to 100 parts by mass of the rubber component is preferably greater than 0.3 part by mass, more preferably greater than 0.4 part by mass, and further preferably greater than 0.5 part by mass. On the other hand, the content is preferably less than 4.0 parts by mass, more preferably less than 3.0 parts by mass, and further preferably less than 2.0 parts by mass. When the content of the vulcanization accelerator is within the above range, it tends to ensure the breaking strength and elongation at break.

[0133] [Rubber composition for airtight layer rubber] Each component of the rubber composition for airtight layer rubber will be described.

[0134] (Rubber component) The description of the rubber component is as described below, in addition to the description in the rubber composition for separator rubber. The rubber composition for airtight layer rubber contains a rubber component containing butyl rubber. In this case, the rubber component may contain rubber components other than butyl rubber. As such rubber components other than butyl rubber, the rubber components described in the above rubber composition for separator rubber can be used. In addition, the rubber component may also consist only of butyl rubber. The description of butyl rubber is as follows.

[0135] 《Butyl rubber》 As the butyl rubber, a polymer containing isobutene units and isoprene units as repeating units and its derivatives are preferred. As such butyl rubber, butyl rubber (IIR); halogenated butyl rubbers such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR) can be cited. Among them, from the point of view of being able to improve the sheet processability and air barrier property well in balance, halogenated butyl rubber is preferred, and brominated butyl rubber and chlorinated butyl rubber are more preferred. These can be used singly or in combination of two or more.

[0136] As the butyl rubber, in addition to ordinary butyl rubber (butyl rubber other than recycled butyl rubber), recycled butyl rubber can also be used in combination. Since the content of unhalogenated butyl rubber (ordinary butyl rubber) in recycled butyl rubber is relatively high, good air barrier property and vulcanization rate can be ensured by using it in combination with halogenated butyl rubber. Recycled butyl rubber can be used alone or in combination of two or more.

[0137] In the rubber component, other rubber components may be contained in addition to butyl rubber. For example, diene rubbers such as isoprene rubber (IR rubber), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR) can be cited. For these other rubber components, the description of the rubber composition for the separator rubber can be equally applied. These other rubber components can be used alone or in combination of two or more.

[0138] 《Content》 From the viewpoint of sufficient air barrier property, the content of butyl rubber in 100% by mass of the rubber component is preferably more than 70% by mass, more preferably more than 75% by mass, further preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0139] (Filler) The filler may contain carbon black. In addition, the filler may contain recycled carbon black (rCB) and silica. When the filler contains silica, a silane coupling agent may be further contained. The filler may further contain other fillers other than carbon black and silica. Preferably, the filler contains carbon black and recycled carbon black. The description of each component that can constitute the filler is as described in the item of the rubber composition for the separator rubber.

[0140] 《Content of carbon black》 When carbon black is contained, the total content of carbon black including recycled carbon black is, for example, more than 20 parts by mass, preferably more than 40 parts by mass, more preferably 50 parts by mass or more, and further preferably 60 parts by mass or more with respect to 100 parts by mass of the rubber component. On the other hand, the total content is preferably less than 150 parts by mass, more preferably less than 110 parts by mass, and further preferably less than 80 parts by mass. When the content of carbon black is within the above range, sufficient reinforcing property can be obtained, the dispersion in the rubber is good, and sufficient rubber strength and crack growth resistance tend to be obtained.

[0141] When the filler contains recycled carbon black, from the viewpoint of reinforcing property, the content ratio of recycled carbon black in the total content of carbon black is, for example, more than 10% by mass, preferably more than 20% by mass, more preferably more than 30% by mass, and further preferably 40% by mass or more.

[0142] For other carbon black (including recycled carbon black), the description of the rubber composition for the separator rubber can be equally applied.

[0143] (Other compounding agents) For the description other than the above, the description of the rubber composition for the separator rubber can be equally applied.

[0144] <Other rubber components constituting the tire> In this specification, the tire may include other rubber components other than those described above. As such other rubber components, there is no particular limitation, and various components commonly used in tires can be used.

[0145] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can also be derived from carbon dioxide in the atmosphere. As a method for obtaining the compounding agent according to the embodiment of the present invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process of synthesizing methane from carbon dioxide can be converted.

[0146] <Use> In this specification, the tire can be a pneumatic tire or a non-pneumatic tire, but preferably it can be used as a pneumatic tire. In addition, in this specification, the tire can be used for various purposes such as passenger car tires, load-carrying tires for trucks / buses, motorcycle tires, and high-performance tires.

[0147] <Manufacturing method> The tire according to this embodiment can be manufactured by a known method.

[0148] (Manufacture of rubber composition) Each of the above rubber compositions can be manufactured by a known method. For example, it can be manufactured by kneading the above components using a rubber kneading device such as an open roll mill or a closed kneader (Banbury mixer, kneader, etc.). The kneading process, for example, includes the following basic kneading process: kneading compounding agents and additives other than the vulcanizing agent and the vulcanization accelerator, and the final kneading process (F kneading): adding the vulcanizing agent and the vulcanization accelerator to the kneaded product obtained in the basic kneading process and kneading. Further, the above basic kneading process can also be decomposed into multiple processes as needed. As kneading conditions, there is no particular limitation. For example, in the basic kneading process, kneading can be performed at a discharge temperature of 150 to 170 °C for 3 to 10 minutes, and in the final kneading process, kneading can be performed at 50 to 110 °C for 1 to 5 minutes.

[0149] (Manufacture of tire) Each of the rubber compositions obtained above can be extruded and processed into the shape of a desired tire component in the unvulcanized stage, and can be used as an unvulcanized separator and an airtight layer respectively. The tire according to this embodiment can be formed by using the separator and the airtight layer obtained in this way, together with other tire components, on a tire forming machine by a conventional method to obtain an unvulcanized tire. By heating and pressurizing (vulcanizing) the unvulcanized tire in a vulcanizer, a tire can be obtained. As vulcanization conditions, there is no particular limitation. For example, a method of vulcanizing at 150 to 200 °C for 5 to 30 minutes can be cited.

Examples

[0150] The following shows examples (Examples) considered to be preferred during implementation, but the scope of the present invention is not limited to the Examples. The rubber compositions and tires obtained using various reagents shown below according to each table were studied, and the results calculated based on the following evaluation methods are shown as durability indices in the lower half of each table.

[0151] <Materials> The materials used in the Examples and Comparative Examples are summarized and described below. Natural rubber: SVR-L SBR: SBR1502 (manufactured by JSR Corporation, styrene content: 23.5% by mass, vinyl content: 18%, Mw: 500,000) Butyl rubber 1: BB2222 (manufactured by ExxonMobil, bromobutyl rubber) Butyl rubber 2: Chlorobutyl HT1066 (manufactured by ExxonMobil, chlorobutyl rubber) Carbon black: SHOBLACK N660 (manufactured by Cabot Japan Co., Ltd., N2SA: 35m 2 / g; ash content: 0.5% by mass) Recycled carbon black (rCB): Carbon black obtained from the thermal cracking process of tires (ash content: 17% by mass) Oil 1: DIANA PROCESS NH-70S (manufactured by Idemitsu Kosan Co., Ltd., aromatic process oil) Oil 2: PS-32 (manufactured by Idemitsu Kosan Co., Ltd., mineral oil) Zinc oxide: Zinc oxide No. 2 (manufactured by Mitsui Mining & Smelting Co., Ltd.) Stearic acid: Stearic acid beads "TSUBAKI" (manufactured by NOF Corporation) Sulfur: HK-200-5 (manufactured by Hosoi Chemical Industry Co., Ltd., powdered sulfur, oil content: 5% by mass) Vulcanization accelerator 1: NOCCELLER CZ (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazole sulfenamide) Vulcanization accelerator 2: NOCCELLER DM (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., 2,2'-dibenzothiazolyl disulfide)

[0152] <Rubber composition for innerliner> According to the compounding recipes shown in Table 1 and Table 2, using a 1.7L closed Banbury mixer, the reagents other than sulfur and vulcanization accelerators were kneaded for 5 minutes at a discharge temperature of 150°C. Then, sulfur and vulcanization accelerators were added to the obtained kneaded material, and kneaded with an open roll mill for 4 minutes until reaching 105°C to obtain an unvulcanized rubber composition for the chafer

[0153] <Rubber composition for airtight layer> According to the compounding recipes shown in Table 1 and Table 2, using a 1.7L closed Banbury mixer, the reagents other than sulfur and vulcanization accelerators were kneaded for 4 minutes until the discharge temperature reached 130°C to obtain a kneaded material. Then, using a biaxial open roll mill, sulfur and vulcanization accelerators were added to the obtained kneaded material, and kneaded for 4 minutes until reaching 80°C to obtain an unvulcanized rubber composition for the airtight layer.

[0154] <Tire> According to the descriptions in Table 1 and Table 2, by shaping the unvulcanized rubber composition for the chafer and the unvulcanized rubber composition for the airtight layer into the shape of the chafer (thickness 0.4mm) and the shape of the airtight layer respectively, and further bonding with other components to form an unvulcanized tire, press vulcanization was carried out at 170°C for 12 minutes to manufacture each test tire (size: 195 / 65R15).

[0155] <Evaluation> For each test tire, the results evaluated based on the following evaluation methods are recorded in the corresponding columns of the above tables.

[0156] <70°C tanδ> Using a dynamic viscoelasticity measuring device, measurements were carried out at a temperature of 70°C, a frequency of 10Hz, an initial strain of 10%, a dynamic strain of ±1%, and in a tensile mode. The sample was a composite of the chafer and the airtight layer cut from the tire with a length of 20mm × width of 4mm × thickness of 1mm. The length direction of the sample was aligned with the tire circumferential direction, and the thickness direction of the sample was aligned with the tire radial direction. When collecting the sample, the thickness of the airtight layer was appropriately adjusted so that the thickness of the composite including the chafer was 1mm.

[0157] <Air permeability coefficient> The air permeability coefficient at 20°C (cm 3 ·cm / (cm 2 ·s·cmHg)) was calculated based on Appendix 2 of JIS K 7126-1 (Gas permeability test method based on gas chromatography), using a gas permeability measuring device (GTR-11A / 31A manufactured by GTR Tech Co., Ltd.), for the measurement results of the airtight layer. The smaller the air permeability coefficient, the smaller the air permeation amount and the better the air barrier property.

[0158] <Air permeability resistance> Assemble each test tire on a standard rim 15×6.0JJ, fill it with air, and set the internal pressure to 230 kPa. Install this tire on a drum-type driving test machine and apply the standard load. Under the condition of a speed of 80 km / h, make this tire run on the drum for 30,000 km, and measure the air pressure. The air permeability resistance index is expressed as an index with the air pressure of the comparison reference example (Comparative Example 2) after running as 100. The larger this value is, the more excellent the air permeability resistance after long-term running is.

[0159] <Tire durability> Assemble each test tire on a standard rim 15×6.0JJ, fill it with air, and set the internal pressure to 230 kPa. Install this tire on a drum-type driving test machine and apply the standard load. Under the condition of a speed of 80 km / h, make this tire run on the drum, and measure the running distance until the airtight layer or the separator rubber breaks. The result is expressed as an index with the running distance of the comparison reference example (Comparative Example 2) as 100. The larger the value is, the better it is.

[0160] Take the sum of the air permeability resistance index and the tire durability index as the comprehensive performance index.

[0161]

Table 1

[0162]

Table 2

[0163] <Embodiment> The following shows preferred embodiments.

[0164] [1] A tire, characterized in that it is a tire having an airtight layer and a separator rubber that contacts the airtight layer on the outer side in the tire radial direction of the airtight layer, the separator rubber is composed of a rubber composition containing recycled carbon black, the air permeability coefficient of the rubber composition constituting the airtight layer is less than 18×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), the thickness of the airtight layer on the tire equator is 1.5 mm or less, preferably 1.4 mm or less, the loss tangent 70℃tanδ of the composite body of the separator rubber and the airtight layer at 70℃ is 0.22 or less, preferably 0.21 or less, more preferably 0.20 or less. [2] The tire according to [1], wherein the thickness of the airtight layer on the tire equatorial plane is 1.2 mm or less, more preferably 1.1 mm or less. [3] The tire according to [1] or [2], wherein the air permeability coefficient of the rubber composition constituting the airtight layer is 17×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, preferably 16×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less, more preferably less than 15×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg), further preferably 14.0×10 -11 cm 3 ·cm / (cm 2 ·s·cmHg) or less. [4] The tire according to any one of [1] to [3], wherein the rubber composition constituting the separator rubber contains a rubber component containing more than 20% by mass, preferably more than 30% by mass, more preferably more than 40% by mass, and further preferably 50% by mass or more of isoprene rubber, and the rubber composition constituting the airtight layer contains a rubber component containing more than 70% by mass, preferably more than 75% by mass, more preferably 80% by mass or more, and further preferably 90% by mass or more of butyl rubber. [5] The tire according to any one of [1] to [4], wherein the statistical thickness specific surface area (STSA) (m 2 / g) of the recycled carbon black is greater than 37 m 2 / g, preferably greater than 40 m 2 / g, more preferably greater than 45 m 2 / g, and in addition less than 77 m 2 / g, preferably less than 75 m 2 / g, more preferably less than 73 m 2 / g, and the ash content (% by mass) is greater than 11% by mass, preferably 13% by mass or more, more preferably 15% by mass or more, further preferably 16% by mass or more, further preferably 17% by mass or more, and less than 27% by mass, preferably less than 26% by mass, more preferably less than 25% by mass.

Claims

1. A tire, characterized in that: The tire comprises an airtight layer and a spacer rubber in contact with the airtight layer on the outer side of the airtight layer in the tire radial direction. The isolation rubber is composed of a rubber composition containing recycled carbon black. The air permeability coefficient of the rubber composition constituting the airtight layer is less than 18×10 -11 cm 3 cm / (cm 2 ·s·cmHg), The thickness of the airtight layer on the tire equatorial plane is less than 1.5 mm, The loss tangent 70°C tanδ of the composite of the isolation adhesive and the airtight layer at 70°C is less than 0.

22.

2. The tire according to claim 1, wherein: The thickness of the airtight layer on the tire equatorial plane is less than 1.2 mm.

3. The tire according to claim 1 or 2, wherein: The air permeability coefficient of the rubber composition constituting the airtight layer is 1.0×10 -13 cm 3 cm / (cm 2 ·s·cmHg) or above.

4. The tire according to claim 1 or 2, wherein: The thickness of the inner liner on the tire equatorial plane is 0.01 mm or more.

5. The tire according to claim 1 or 2, wherein: The composite of the isolation adhesive and the airtight layer has a loss tangent 70°C tanδ of greater than 0.01 at 70°C.

6. The tire according to claim 1 or 2, wherein: The air permeability coefficient of the rubber composition constituting the airtight layer is less than 15×10 -11 cm 3 cm / (cm 2 ·s·cmHg).

7. The tire according to claim 1 or 2, wherein: The rubber composition constituting the insulation rubber includes a rubber component containing more than 20% by mass of isoprene-based rubber, and the rubber composition constituting the inner liner includes a rubber component containing more than 70% by mass of butyl-based rubber.

8. The tire according to claim 1 or 2, wherein: The statistical thickness specific surface area STSA of the regenerated carbon black is greater than 37 m 2 / g, less than 77m 2 / g, and the ash content is greater than 11 mass % and less than 27 mass %.

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