RFID tag coating rubber composition and tire

Abstract

The present invention addresses the problem of providing: an RFID tag coating rubber composition capable of improving the proportion of sustainable materials in a tire; and a tire having an improved proportion of sustainable materials. Solutions to the problem are: an RFID tag coating rubber composition that is characterized by comprising a rubber component (A) and silica (B), and that is characterized in that the silica (B) contains plant-derived silica (B1), and the contained amount of the silica (B) is at least 45 parts by mass with respect to 100 parts by mass of the rubber component (A); and a tire (1) characterized by comprising an RFID tag (12) coated with the RFID tag coating rubber composition.

Description

Rubber coating composition for RFID tags, and tires

[0001] This invention relates to a coating rubber composition for RFID tags and to tires.

[0002] Conventionally, it has been proposed to install RFID (Radio Frequency Identification) tags in tires and to write or read various information such as the tire's manufacturing history, distribution history, and usage history to the RFID tags in order to manage each tire individually (Patent Document 1). The RFID tags are usually coated with rubber so that they can be installed in tires, which are mainly made of rubber material. The coating rubber for these RFID tags has various required characteristics, including communication performance, crack resistance, adhesion to adjacent rubber material, and an appropriate modulus of elasticity.

[0003] European Patent No. 1580041

[0004] On the other hand, in recent years, from the perspective of social sustainability, there has been a demand to increase the proportion of so-called sustainable materials, such as materials derived from biological resources (biomass resources) and recycled resources, in the various components used in tires. However, the use of sustainable materials has not been considered for the coating rubber for the RFID tags mentioned above.

[0005] Therefore, the object of the present invention is to provide a coating rubber composition for RFID tags that can improve the proportion of sustainable materials in tires. Furthermore, the object of the present invention is to provide a tire with an improved proportion of sustainable materials.

[0006] The essential structure of the RFID tag coating rubber composition and tire of the present invention, which solve the above problems, is as follows.

[0007] [1] A coating rubber composition for RFID tags, comprising a rubber component (A) and silica (B), wherein the silica (B) comprises plant-derived silica (B1), and the silica (B) content is 45 parts by mass or more per 100 parts by mass of the rubber component (A).

[0008] [2] The RFID tag coating rubber composition according to [1], further comprising a silane coupling agent (C).

[0009] [3] The RFID tag coating rubber composition according to [2], wherein the content of the silane coupling agent (C) is 5 to 20% by mass of the content of the silica (B).

[0010] [4] The RFID tag coating rubber composition according to any one of [1] to [3], wherein the silica (B) content is 45 to 90 parts by mass per 100 parts by mass of the rubber component (A).

[0011] [5] The RFID tag coating rubber composition according to any one of [1] to [4], wherein the plant-derived silica (B1) is silica derived from grasses.

[0012] [6] The RFID tag coating rubber composition according to [5], wherein the plant-derived silica (B1) is silica derived from rice husks.

[0013] [7] The RFID tag coating rubber composition according to any one of [1] to [6], wherein the carbon black content is 15 parts by mass or less per 100 parts by mass of the rubber component (A).

[0014] [8] The RFID tag coating rubber composition according to any one of [1] to [7], wherein the content ratio of silica (B) in the total content of silica (B) and carbon black is 80 to 100% by mass.

[0015] [9] A tire characterized by comprising an RFID tag coated with any one of the RFID tag coating rubber compositions described in [1] to [8].

[0016] According to the present invention, it is possible to provide a coating rubber composition for RFID tags that can improve the proportion of sustainable materials in tires. Furthermore, according to the present invention, it is possible to provide tires with an improved proportion of sustainable materials.

[0017] This is a cross-sectional view of one embodiment of the tire of the present invention.

[0018] Hereinafter, the coating rubber composition for RFID tags and the tire of the present invention will be specifically illustrated and described based on their embodiments.

[0019] <Definition> The compounds described in this specification may be partially or entirely derived from fossil resources, may be derived from biological resources such as plant resources, or may be derived from recycled resources such as used tires. Further, it may be derived from a mixture of any two or more of fossil resources, biological resources, and recycled resources.

[0020] In this specification, the "ratio of sustainable materials" refers to the total mass ratio of materials derived from biological resources (biomass resources) and materials derived from recycled resources (recycled resources) in the target coating rubber composition for RFID tags and tires.

[0021] In this specification, the biological resources (biomass resources) refer to carbon-neutral organic resources derived from organisms, and include, for example, those stored in the form of starch or cellulose, the bodies of animals that grow by eating plants, and products obtained by processing plants and animals. Resources excluding fossil resources (oil, coal, natural gas, etc.). The biological resources may be edible or inedible, but do not compete with food, and from the perspective of effective utilization of resources, it is preferably inedible.

[0022] Specific examples of the aforementioned biological resources include, for example, cellulosic crops (pulp, kenaf, wheat straw, rice straw, waste paper, papermaking residue, etc.), wood, charcoal, compost, food waste, vegetable oil residue, fishery product residue, livestock excrement, food waste, wastewater sludge, natural rubber, cotton, oils and fats (palm oil, castor oil, cottonseed oil, soybean oil, linseed oil, rapeseed oil, coconut oil, peanut oil, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, etc.). Examples of biological resources include oat oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil, coconut oil, etc.), carbohydrate crops (corn, wheat, rice, rice husks, rice bran, old rice, potatoes, buckwheat, cassava, sago palm, sugarcane, etc.), bagasse (i.e., residue after sugarcane juicing), soybeans, okara (soy pulp), essential oils (pine root oil, orange oil, eucalyptus oil, etc.), black pulp liquor, algae, etc. Processed versions of these biological resources (i.e., biological resource-derived materials) can also be used. Processing methods include, for example, biological processing methods utilizing the functions of microorganisms, plants, animals, and their tissue cultures; chemical processing methods utilizing acids, alkalis, catalysts, thermal energy, light energy, etc.; and physical processing methods such as micronization, compression, microwave processing, and electromagnetic wave processing. Furthermore, extracted and purified materials (i.e., biological resource-derived materials) from the biological resources or biological resources that have undergone the processing can also be used. For example, sugars, proteins, amino acids, fatty acids, fatty acid esters, etc., purified from the aforementioned biological resources can also be used. Examples of the aforementioned sugars include sucrose, glucose, trehalose, fructose, lactose, galactose, xylose, allose, talose, growth, altrose, mannose, idose, arabinose, apiose, maltose, cellulose, starch, chitin, etc., all derived from biological resources. Examples of the aforementioned proteins include compounds formed by linking amino acids (preferably L-amino acids) derived from biological resources, and also include oligopeptides such as dipeptides. Examples of the aforementioned amino acids include valine, leucine, isoleucine, arginine, lysine, asparagine, glutamine, phenylalanine, etc., all derived from biological resources, with valine, leucine, isoleucine, arginine, and phenylalanine being preferred among these.The amino acid may be an L-amino acid or a D-amino acid, but from the perspective of abundance in nature and ease of availability, L-amino acids are preferred. Examples of the fatty acid include those derived from biological resources, such as butyric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Examples of the fatty acid ester include vegetable oils, animal oils, and modified products of oils and fats derived from biological resources. These biological resources may contain various materials and impurities.

[0023] As used herein, the recycled resource refers to a resource obtained by recycling a product that has been used once, collected without being used, or discarded. For example, recycled resources include resources obtained by recycling used rubber products such as used tires.

[0024] <Coating Rubber Composition for RFID Tag> The coating rubber composition for an RFID tag according to this embodiment contains a rubber component (A) and silica (B). In the coating rubber composition for an RFID tag according to this embodiment, the silica (B) contains plant-derived silica (B1), and the content of the silica (B) is 45 parts by mass or more with respect to 100 parts by mass of the rubber component (A).

[0025] Conventional rubber compositions contain carbon black, but carbon black increases the dielectric constant of the rubber composition, shortening the communication range (communicable distance) of RFID tags and degrading communication performance. If carbon black is not used, the crack resistance and elastic modulus of the rubber composition will decrease. In contrast, the RFID tag coating rubber composition of this embodiment contains silica (B), and unlike carbon black, silica (B) does not increase the dielectric constant of the rubber composition, thus extending the communication range of RFID tags and improving communication performance. Furthermore, by having a silica (B) content of 45 parts by mass or more per 100 parts by mass of the rubber component (A), sufficient crack resistance and elastic modulus of the rubber composition can be ensured. In addition, the rubber composition having sufficient elastic modulus suppresses stress concentration on the RFID tag coated with the rubber composition, and ensures adhesion between the rubber composition (coating) and adjacent rubber members. Therefore, the RFID tag coating rubber composition of this embodiment can adequately balance communication performance, crack resistance, adhesion to adjacent rubber members, and elastic modulus.

[0026] Here, regarding the communication performance, the relative permittivity of the rubber composition at 860 MHz can be measured using a relative permittivity meter. Furthermore, since it is known from past measurement results of relative permittivity that the relative permittivity can be estimated from the amount of carbon black in the rubber compound, the relative permittivity can also be calculated.

[0027] Furthermore, in the RFID tag coating rubber composition of this embodiment, since the plant-derived silica (B1) is a material derived from biological resources (biomass resources), the proportion of sustainable materials in the RFID tag coating rubber composition of this embodiment is improved. Therefore, by applying an RFID tag coated with the RFID tag coating rubber composition of this embodiment to a tire, it becomes possible to improve the proportion of sustainable materials in the tire. Note that in a rubber composition containing rubber component (A) and silica (B), where the silica (B) content is 45 parts by mass or more per 100 parts by mass of rubber component (A), even if the silica (B) contains plant-derived silica (B1), the performance such as communication performance will not be impaired.

[0028] (Rubber component (A)) The RFID tag coating rubber composition of this embodiment contains rubber component (A), which provides rubber elasticity to the composition. The sustainability rate of rubber component (A) is preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass. Here, the "sustainability rate" of rubber component (A) is the total mass ratio of components derived from biological resources (biomass resources) and components derived from recycled resources in rubber component (A).

[0029] The rubber component (A) is preferably the rubber derived from biological resources and the rubber derived from recycled resources. Here, the proportion of the monomer component derived from biological resources in 100 mol% of the monomer component constituting the rubber derived from biological resources is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, and may also be 100 mol%. Furthermore, the proportion of the monomer component derived from recycled resources in 100 mol% of the monomer component constituting the rubber derived from recycled resources is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, and may also be 100 mol%.

[0030] The rubber component (A) is a component that contributes to crosslinking, and typically has a weight-average molecular weight (Mw) of 10,000 or more, preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and also preferably 5,000,000 or less, more preferably 2,000,000 or less, even more preferably 1,500,000 or less, and even more preferably 1,300,000 or less. In this specification, the weight-average molecular weight (Mw) of the rubber component (A) can be determined, for example, by converting it to standard polystyrene based on measurements obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIIPORE HZ-M manufactured by Tosoh Corporation).

[0031] The rubber component (A) is preferably a diene-based rubber, and the diene-based rubber is preferably isoprene-based rubber or butadiene-based rubber. Here, isoprene-based rubber refers to rubber that contains units derived from isoprene as monomer units, and butadiene-based rubber refers to rubber that contains units derived from butadiene as monomer units.

[0032] Examples of isoprene-based rubbers include natural rubber (NR), synthetic isoprene rubber (IR), modified natural rubber (modified NR), modified natural rubber (modified NR), and modified synthetic isoprene rubber (modified IR). Examples of natural rubber (NR) include RSS#3, TSR20 (e.g., SIR20 and STR20), which are common in the tire industry. The origin of natural rubber (NR) is not particularly limited and examples include rubber derived from the Para rubber tree, guayule, and Russian dandelion. Examples of synthetic isoprene rubber (IR) are not particularly limited and examples include IR2200, which are common in the tire industry. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR rubbers include epoxidized synthetic isoprene rubber, hydrogenated synthetic isoprene rubber, and grafted synthetic isoprene rubber. These isoprene-based rubbers may be used individually or in combination of two or more types. Among these, NR is preferred as the isoprene-based rubber.

[0033] The isoprene-based rubber preferably has a sustainability rate of 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass. In order to make the sustainability rate of the isoprene-based rubber within the above range, it is preferable to use natural rubber (NR) or a polymer synthesized using isoprene derived from biological resources or isoprene derived from recycled resources as monomer components. In this case, the synthesized polymer may be a homopolymer of monomers derived from biological resources, a homopolymer of monomers derived from recycled resources, a copolymer of monomers derived from biological resources and monomers derived from recycled resources, or a copolymer of monomers derived from biological resources and / or monomers derived from recycled resources and monomers derived from fossil resources (petroleum, etc.).

[0034] Examples of the butadiene-based rubber include butadiene rubber (BR), aromatic vinyl compound-butadiene copolymer rubber (for example, styrene-butadiene rubber (SBR)), etc. Here, it is preferable that the butadiene used as a raw material for the butadiene-based rubber is derived from biological resources or recycled resources.

[0035] Examples of the butadiene rubber (BR) include high-cis content butadiene rubber, low-cis content butadiene rubber, and butadiene rubber containing syndiotactic polybutadiene crystals. Commercially available butadiene rubber (BR) can be used, and examples of such commercially available butadiene rubber include products from UBE Elastomer Co., Ltd., ENEOS Materials Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation. These butadiene rubbers may be used individually or in combination of two or more types.

[0036] Examples of the aromatic vinyl compound-butadiene copolymer rubber (e.g., SBR) include emulsion polymerized aromatic vinyl compound-butadiene copolymer rubber (e.g., emulsion polymerized styrene-butadiene rubber (E-SBR)) and solution polymerized aromatic vinyl compound-butadiene copolymer rubber (e.g., solution polymerized styrene-butadiene rubber (S-SBR)). In the aromatic vinyl compound-butadiene copolymer rubber, examples of the aromatic vinyl compound (aromatic vinyl monomer) include styrene, vinylnaphthalene, and divinylnaphthalene. These aromatic vinyl compounds may be used individually or in combination of two or more. Among these, styrene is preferred, and styrene derived from biological resources and styrene derived from recycled resources are particularly preferred. That is, SBR is preferred as the aromatic vinyl compound-butadiene copolymer rubber. The styrene may have substituents. The aromatic vinyl compound-butadiene copolymer rubber can be a commercially available product, and examples of such commercially available products include those from Asahi Kasei Corporation, ENEOS Materials Corporation, Zeon Corporation, and Sumitomo Chemical Co., Ltd. These aromatic vinyl compound-butadiene copolymer rubbers may be used individually or in combination of two or more types.

[0037] The butadiene-based rubber preferably has a sustainability rate of 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass. In order to make the sustainability rate of the butadiene-based rubber within the above range, for example, a polymer synthesized using butadiene derived from biological resources, butadiene derived from recycled resources, aromatic vinyl compounds derived from biological resources (e.g., styrene derived from biological resources), or aromatic vinyl compounds derived from recycled resources (e.g., styrene derived from recycled resources) as monomer components may be used. In this case, the synthesized polymer may be a homopolymer of monomers derived from biological resources, a homopolymer of monomers derived from recycled resources, a copolymer of monomers derived from biological resources and monomers derived from recycled resources, or a copolymer of monomers derived from biological resources and / or monomers derived from recycled resources and monomers derived from fossil resources (petroleum, etc.). Furthermore, the term "butadiene rubber (B-BR) derived from biological resources (biomass resources)" and "aromatic vinyl compound-butadiene copolymer rubber (for example, styrene-butadiene rubber (B-SBR) derived from biological resources (biomass resources))" includes not only rubber obtained by polymerizing butadiene etc. according to conventional methods, but also rubber obtained by reactions or enzymatic reactions involving microorganisms, plants, animals, and their tissue cultures (hereinafter also referred to as "microorganisms, etc.").

[0038] Furthermore, in order to keep the overall sustainability rate of the rubber component (A) within the aforementioned range, it is preferable to use natural rubber (NR) as the rubber component (A), or to use a polymer synthesized using monomer components derived from biological resources or monomer components derived from recycled resources as monomer components.

[0039] Generally, the materials for tire rubber compositions (rubber and its monomers, fillers, resins, etc.) require large-scale manufacturing equipment for production, and are typically produced in large factories in specific regions, requiring significant energy for the storage and transportation of raw materials and finished products. In contrast, materials derived from biological resources (biomass resources) are derived from agricultural products, forests, etc., in each region, and can be produced on a small scale through microbial fermentation and catalytic reactions. By utilizing local produce and waste, the energy required for the transportation and storage of raw materials can be reduced, as can the energy required for the transportation and storage of the manufactured materials to tire factories, making them environmentally friendly. Furthermore, materials derived from recycled resources can be obtained, for example, by dismantling and thermally decomposing used tires to extract materials that make up tires, such as rubber, fillers, and steel cords. In addition, sulfur can be obtained from biological resources or processed biological resources by a method (for example, the method described in Japanese Patent Application No. 2022-140390) that includes a desulfurization step of desulfurizing biological resources or processed biological resources to remove sulfur-containing substances from said biological resources or processed biological resources, a recovery step of recovering sulfur from the desulfurization residue generated in the desulfurization step, and a processing step of processing the recovered sulfur into sulfur for vulcanization, and thus materials for tire rubber compositions can be obtained from various wastes and used articles. In this way, by using sustainable materials (materials derived from biological resources or recycled resources), the environmental burden in tire manufacturing can be comprehensively reduced, including a reduction in carbon dioxide emissions (LCCO2) over the entire lifecycle, a reduction in energy consumption (LCE) over the entire lifecycle, a reduction in costs incurred over the entire lifecycle (LCC), and a reduction in the use of fossil resources.

[0040] Furthermore, when manufacturing the rubber composition, depending on the supply situation of biological resources, recycled resources, and fossil resources (e.g., monomer components derived from fossil resources) and / or market demands (e.g., demand for biological resources as food), the ratio of monomer components derived from biological resources, monomer components derived from recycled resources, and monomer components derived from fossil resources can be appropriately selected, and by polymerizing these monomer components, it is possible to obtain rubber derived from sustainable materials (materials derived from biological resources or recycled resources) that has performance equivalent to that of conventional synthetic rubber. Note that when using monomer components derived from recycled resources, it may be difficult to separate them from monomer components derived from fossil resources due to the manufacturing process of the monomers. In such cases, the environmental impact can be evaluated by adopting the concept of mass balance.

[0041] The ratio of each monomer unit (for example, units derived from isoprene, units derived from butadiene, and units derived from aromatic vinyl compounds) in the entire rubber component (A) can be appropriately adjusted depending on the member to which it is applied. The ratio of each monomer unit in the entire rubber component can be adjusted, for example, by appropriately combining the isoprene-based rubber and butadiene-based rubber mentioned above. The ratio of cis-bonded units in the butadiene-derived units can also be appropriately adjusted depending on the member to which it is applied. In this specification, "monomer unit" means a constituent unit of a polymer, "unit derived from isoprene" means a constituent unit in a polymer composed of isoprene, which is a monomer (including isoprene units in natural rubber), "unit derived from butadiene" means a constituent unit in a polymer composed of butadiene, which is a monomer, and "unit derived from aromatic vinyl compounds" means a constituent unit in a polymer composed of aromatic vinyl compounds, which are monomers. In this specification, the ratio of each monomer unit is measured by NMR.

[0042] In addition to the isoprene-based rubber, butadiene rubber (BR), and aromatic vinyl compound-butadiene copolymer rubber (e.g., SBR) mentioned above, the rubber component (A) may also include diene-based rubbers such as acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). These rubber components may be used individually or in combination of two or more.

[0043] The rubber component (A) may have functional groups that interact with fillers such as carbon black and silica introduced through modification. Examples of such functional groups include amino groups, amide groups, isocyanate groups, imino groups, imidazole groups, urea groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, ether groups, carbonyl groups, oxycarbonyl groups, silyl groups, alkoxysilyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, and thiocarbonyl groups. These functional groups may also have substituents. These functional groups may be introduced into the rubber component individually or in combination of two or more. Among these, amino groups, alkoxy groups, and alkoxysilyl groups are preferred, and substituted amino groups in which the hydrogen atoms of the amino group are replaced by alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and alkoxysilyl groups having 1 to 6 carbon atoms are even more preferred.

[0044] The functional group can be introduced, for example, by reacting a compound having the functional group (modifier) ​​with the rubber component (A). The functional group is a modifying functional group that interacts with fillers such as silica and carbon black, and examples include nitrogen-containing functional groups, silicon-containing functional groups, and oxygen-containing functional groups. Examples of compounds having nitrogen-containing functional groups (modifiers) include amino group-containing compounds, examples of compounds having silicon-containing functional groups (modifiers) include silicon halides and hydrocarbyloxysilane compounds, and examples of compounds having oxygen-containing functional groups (modifiers) include alkoxy group-containing compounds, alkylene oxide group-containing compounds, and trialkylsilyloxy group-containing compounds. More specifically, examples include compounds described in International Publication No. 2016 / 194316 and International Publication No. 2019 / 117256. These modifiers may be used individually or in combination of two or more.

[0045] The rubber derived from the aforementioned sustainable materials (materials derived from biological resources or materials derived from recycled resources) can be manufactured, for example, using monomer components derived from biological resources or monomer components derived from recycled resources, and optionally using monomer components derived from fossil resources, in the same manner as conventional methods for manufacturing synthetic rubber derived from fossil resources. Furthermore, the rubber derived from the aforementioned sustainable materials (especially rubber derived from biological resources) can also be obtained by reactions involving microorganisms or enzymatic reactions.

[0046] Regarding the method for preparing bio-derived rubber from the above-mentioned biological resources, for example, the method described in Japanese Patent Application Publication No. 2022-179158 can be used. For example, by using butadiene obtained from biological resources as a monomer component, bio-derived butadiene rubber (B-BR) can be obtained, and by using styrene obtained from biological resources and butadiene obtained from biological resources as monomer components, bio-derived styrene-butadiene rubber (B-SBR) can be obtained. Here, methods for obtaining B-BR and B-SBR from biological resources include artificial polymerization, polymerization in vivo, and polymerization using biologically derived enzymes. The molecular weight, branching, microstructure, etc. of the obtained B-BR and B-SBR can be appropriately adjusted by changing the polymerization conditions according to known methods, depending on the desired tire performance.

[0047] As the butadiene obtained from the aforementioned biological resources, butadiene derived from alkyl alcohols (preferably ethanol and butanol, more preferably butanol), butadiene derived from alkenes (preferably ethylene), and butadiene derived from unsaturated carboxylic acids (preferably tigric acid) can be suitably used. Two or more of these butadienes may also be used in combination. As the styrene obtained from the aforementioned biological resources, styrene obtained from plants (preferably plants belonging to the Hamamelidaceae, Styracaceae, and Apocynaceae families, more preferably plants belonging to the genera Liquidambar, Styrax, and Vinca, even more preferably Liquidambar formosana, Styrax japonica, and Vinca) and styrene obtained from microorganisms (preferably microorganisms belonging to the genera Penicillium and Escherichia, more preferably P. citrinum and transformed E. coli) can be suitably used. Two or more of these styrenes may also be used in combination.

[0048] Recently, biomass complexes focusing on bioethanol and bioethylene are being planned. However, bioethanol and bioethylene are produced using mainly sugars and / or celluloses as biological resources, and other biological resources such as proteins, lipids, and amino acids cannot be effectively utilized. Furthermore, sugars compete with food, and excessive use of cellulose leads to deforestation. Therefore, depending on the supply situation of various biological resources, as well as the supply situation of recycled resources, the supply situation of fossil resources, and market demands (for example, the demand for biomass resources as food), it is preferable to use multiple types of monomer components derived from biological resources, or to use monomer components derived from biological resources, recycled resources, and fossil resources in combination, and to adjust the ratio of these monomer components as appropriate. This allows for the effective utilization of a wide range of biological resources such as sugars, proteins, and lipids, as well as recycled resources, without relying on a single type of biological resource. It also enables a stable supply of rubber derived from sustainable materials and allows for environmental considerations depending on the circumstances during production. Furthermore, when using multiple types of monomer components derived from biological resources, it is preferable to use monomer components derived from different biological resources, i.e., monomer components obtained from different biological resources. Specifically, it is preferable to use a mixture of multiple types of butadiene derived from different biological resources as the butadiene derived from biological resources, and / or to use a mixture of multiple types of styrene derived from different biological resources as the styrene derived from biological resources. This allows for the effective utilization of multiple types of biological resources.

[0049] (Silica (B)) The RFID tag coating rubber composition of this embodiment contains silica (B), and the silica (B) content is 45 parts by mass or more per 100 parts by mass of the rubber component (A). By blending silica (B) into the rubber composition, the crack resistance and elastic modulus of the rubber composition can be improved without increasing the dielectric constant of the rubber composition. However, if the silica (B) content is less than 45 parts by mass per 100 parts by mass of the rubber component (A), the crack resistance and elastic modulus of the rubber composition will be insufficient. The dielectric constant of the rubber composition is preferably 4.0 or less, and more preferably 2.5 or less, from the viewpoint of the communication distance (communication range) of the RFID tag.

[0050] The silica (B) content is preferably 45 to 100 parts by mass, more preferably 45 to 90 parts by mass, and particularly preferably 60 to 80 parts by mass, per 100 parts by mass of the rubber component (A). If the silica (B) content is 60 parts by mass or more per 100 parts by mass of the rubber component (A), the crack resistance and elastic modulus of the rubber composition can be further improved. If the silica (B) content is less than 45 parts by mass per 100 parts by mass of the rubber component (A), a decrease in crack resistance and elastic modulus will occur. When the silica (B) content is 45 to 100 parts by mass per 100 parts by mass of the rubber component (A), the crack resistance and elastic modulus of the rubber composition can be further improved. Furthermore, when the silica (B) content is 45 to 90 parts by mass per 100 parts by mass of the rubber component (A), the crack resistance and elastic modulus of the rubber composition can be further improved.

[0051] The silica (B) includes plant-derived silica (B1). Since the plant-derived silica (B1) is a material derived from biological resources (biomass resources), including plant-derived silica (B1) improves the proportion of sustainable materials in the RFID tag coating rubber composition. Applying this rubber composition to tires improves the proportion of sustainable materials in the tires and reduces the environmental impact.

[0052] As the plant-derived silica (B1), silica derived from silicate plants is preferred from the viewpoint of reducing environmental impact. These silicate plants include, for example, mosses, ferns, horsetails, cucurbitaceae, nettleaceae, and grasses. Among these plants, grasses are preferred; that is, as the plant-derived silica (B1), silica derived from grasses is preferred. Since silica derived from grasses can be sourced locally near tire manufacturing plants, the energy and costs of transportation and storage can be reduced, which is environmentally friendly from various viewpoints. Examples of grasses include rice, bamboo grass, and sugarcane, and among these, rice is preferred. Since rice is widely cultivated for food, it can be sourced locally in a wide area, and since rice husks are generated in large quantities as industrial waste, it is easy to secure the quantity. Therefore, from the viewpoint of availability, silica derived from rice husks (hereinafter also referred to as "rice husk silica") is particularly preferred as the plant-derived silica (B1). By using this rice husk silica, rice husks that would otherwise be industrial waste can be effectively utilized, and since raw materials can be procured locally near the tire manufacturing plant, the energy and costs of transportation and storage can be reduced, making it environmentally friendly from various viewpoints. The rice husk silica may be powder of rice husk charcoal obtained by carbonizing rice husks by heating, or it may be precipitated silica produced by a wet method using an alkaline aqueous solution of silicate prepared by extracting rice husk ash generated when rice husks are burned as fuel in a biomass boiler with alkali. The method for producing the rice husk charcoal is not particularly limited, and various known methods can be used. For example, rice husk charcoal can be obtained by thermal decomposition by steam-roasting rice husks in a kiln. The rice husk charcoal obtained in this way can be crushed using a known crusher (e.g., a ball mill), sorted into a predetermined particle size range, and classified to obtain rice husk charcoal powder. Furthermore, the precipitated silica derived from rice husks can be produced by the method described in Japanese Patent Publication No. 2019-38728, etc.

[0053] The ratio of plant-derived silica (B1) in silica (B) is preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 25% by mass or more, even more preferably 45% by mass or more, and most preferably 100% by mass. By setting the ratio of plant-derived silica (B1) in silica (B) to 5% by mass or more, the ratio of sustainable materials in the RFID tag coating rubber composition is improved, and by applying the rubber composition to a tire, the ratio of sustainable materials in the tire can be further improved.

[0054] The silica (B) may contain silica other than the plant-derived silica (B1) described above. Examples of such silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate. Among these, wet silica is preferred because it contains a large number of silanol groups. These silicas other than plant-derived silica (B1) may be used individually or in combination of two or more. Commercially available silicas other than plant-derived silica (B1) can be used, and examples of such commercially available silica include products from Tosoh Silica Co., Ltd., Evonik, Solvay, Solvay Japan Ltd., and Tokuyama Corporation.

[0055] Furthermore, from the viewpoint of reducing environmental impact, it is also preferable to use silica (B) that has been recycled by extracting silicic acid components from silicon wafer scraps, which are raw materials for semiconductors, or from glass bottles, etc., and used in the manufacturing process.

[0056] The aforementioned plant-derived silica (B1) has a nitrogen adsorption specific surface area (N ２ SA) is 50m ２ It is preferable that it be 100m or more per gram. ２ It is more preferable that the amount is 150m or more per gram. ２ It is even more preferable that it be 350m or more ２ It is preferable that the amount is less than or equal to 250m ２ It is more preferable that it be less than or equal to 230m ２ It is even more preferable that it be less than or equal to 200m ２More preferably, it is below 0.1 g. In the present specification, the nitrogen adsorption specific surface area (N ２ SA) of silica (B) is a value measured by the BET method in accordance with ASTM D3037-93.

[0057] (Silane coupling agent (C)) The coating rubber composition for RFID tags of the present embodiment preferably further contains a silane coupling agent (C). When the rubber composition contains the silane coupling agent (C), the interaction between the rubber component (A) and silica (B) increases, and the dispersibility of silica (B) in the rubber component (A) is improved. Further, by improving the dispersibility of silica (B) in the rubber component (A), the action of silica (B) can be fully exerted, and the crack resistance and elastic modulus of the rubber composition can be further improved.

[0058] The silane coupling agent (C) may be bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl- Examples include N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, and dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide. The silane coupling agent (C) can be a commercially available product. Examples of commercially available silane coupling agents (C) include those from Evonik, Momentive, Shin-Etsu Silicone Co., Ltd., Toray Dow Corning Co., Ltd., Tokyo Chemical Industry Co., Ltd., and Azumax Co., Ltd. These silane coupling agents may be used individually or in combination of two or more types.

[0059] Furthermore, bioethanol can also be used as a raw material for the silane coupling agent (C). Bioethanol is produced using mainly sugars and / or celluloses as biological resources, and does not allow for the effective utilization of other biological resources such as proteins, lipids, and amino acids. Moreover, sugars compete with food, and excessive use of celluloses leads to deforestation. For this reason, depending on the supply situation of various biological resources, as well as the supply situation of recycled resources, the supply situation of fossil resources, and market demands (for example, the demand for biomass resources as food), it is preferable to use multiple types of ethanol derived from biological resources (bioethanol) as a raw material for the silane coupling agent, or to use a combination of ethanol derived from biological resources (bioethanol), ethanol derived from recycled resources, and ethanol derived from fossil resources. This allows for the effective utilization of a wide range of biological resources such as sugars, proteins, and lipids, as well as recycled resources, without relying on a single type of biological resource, and also allows for environmental considerations depending on the circumstances during production.

[0060] The content of the silane coupling agent (C) is preferably 5 to 20% by mass of the silica (B) content (i.e., 5 to 20 parts by mass per 100 parts by mass of silica (B)). When the content of the silane coupling agent (C) is 5% by mass or more of the silica (B) content, the blending effect of the silane coupling agent (C) is increased, the dispersibility of silica (B) in the rubber component (A) is further improved, and the crack resistance and elastic modulus of the rubber composition can be further improved. Also, when the content of the silane coupling agent (C) is 20% by mass or less of the silica (B) content, gelation of the rubber component (A) can be suppressed. Furthermore, when the content of the silane coupling agent (C) is 5 to 20% by mass of the silica (B) content, the crack resistance and elastic modulus of the rubber composition can be further improved.

[0061] (Vulcanizing agent) The RFID tag coating rubber composition of this embodiment preferably contains a vulcanizing agent. The inclusion of a vulcanizing agent in the rubber composition makes it vulcanizable, improving the crack resistance and elastic modulus of the rubber composition. Sulfur is an example of a vulcanizing agent.

[0062] The sulfur used can be derived from fossil resources, recycled resources, or materials obtained by processing biological resources. From the viewpoint of reducing environmental impact, it is particularly preferable to use sulfur obtained from waste derived from biological resources. An example of a method for obtaining sulfur from waste derived from biological resources is the method described in the above-mentioned Japanese Patent Application No. 2022-140390. In addition, the sulfur used can be powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used as crosslinking agents in the rubber industry. Here, it is preferable that the sulfur includes insoluble sulfur. Insoluble sulfur is sulfur that is insoluble in carbon disulfide (amorphous polymer sulfur), and its solubility in rubber components (A) is lower than that of soluble sulfur, making it less likely to cause blooming. From the viewpoint of further improving workability during tire molding, the proportion of insoluble sulfur in the sulfur is preferably 50% by mass or more, and preferably 90% by mass or less. The sulfur can be a commercially available product, and examples of commercially available sulfur include those from Tsurumi Chemical Industries, Ltd., Hosoi Chemical Industries, Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., and others. These sulfurs may be used individually or in combination of two or more types.

[0063] From the viewpoint of further improving the crack resistance and elastic modulus of the rubber composition, the content of the vulcanizing agent is preferably 5 parts by mass or more, and preferably 9 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0064] (Vulcanization Accelerator) The RFID tag coating rubber composition of this embodiment preferably contains a vulcanization accelerator. By including a vulcanization accelerator in the rubber composition, the vulcanization rate can be increased, and the elastic modulus of the rubber composition can be improved. The vulcanization accelerator can be derived from fossil resources, recycled resources, or biological resources, but from the viewpoint of reducing environmental impact, it is preferable that it be derived from biological resources. A vulcanization accelerator derived from biological resources can be obtained, for example, by the method disclosed in Japanese Patent Application Publication No. 2005-139239.

[0065] The aforementioned vulcanization accelerators include sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolyl sulfenamide, N-tert-butyl-2-benzothiazolyl sulfenamide (TBBS), N-oxyethylene-2-benzothiazolyl sulfenamide, and N,N'-diisopropyl-2-benzothiazolyl sulfenamide; and 1,3-diphenylguanidine (DPG) and 1,3-di-o-tolylguanidine. Examples include guanidine-based vulcanization accelerators such as din and o-trilbiguanidine; thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole (M) and di-2-benzothiazolyl disulfide (MBTS, DM); thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrastearylthiuram disulfide, tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); and dithiocarbamate-based vulcanization accelerators. Among these, sulfenamide-based or guanidine-based vulcanization accelerators are preferred. Among sulfenamide-based vulcanization accelerators, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) is particularly preferred. Among guanidine-based vulcanization accelerators, 1,3-diphenylguanidine (DPG) is particularly preferred. Commercially available products can be used as the vulcanization accelerator, and examples of such commercially available products include those from Ouchi Shinko Chemical Industry Co., Ltd., Sumitomo Chemical Co., Ltd., and others. These vulcanization accelerators may be used individually or in combination of two or more types.

[0066] From the viewpoint of improving the vulcanization rate of the rubber composition and further improving the elastic modulus of the rubber composition, the content of the vulcanization accelerator is preferably 0.0 to 3.0 parts by mass, and more preferably 0.9 to 2.5 parts by mass, per 100 parts by mass of the rubber component (A).

[0067] (Oil) The RFID tag coating rubber composition of this embodiment preferably contains oil. When the rubber composition contains oil, the cohesiveness of the rubber composition during mixing is improved, and the workability of the rubber composition during mixing is improved.

[0068] The aforementioned oils refer to the drawstring oils contained in rubber components and the liquid oils added as compounding agents to rubber compositions. Examples include petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils, vegetable oils, process oils, oils obtained by recycling vegetable oils or process oils, or mixtures thereof. Among these, petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils are preferred from the viewpoint of crack resistance and elastic modulus. Furthermore, from the viewpoint of reducing environmental impact, vegetable oils and recycled oils are preferred as oils. Examples of the aforementioned vegetable oils include palm oil, castor oil, cottonseed oil, soybean oil, linseed oil, rapeseed oil, coconut oil, peanut oil, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil, and coconut oil. Examples of the process oils include paraffin-based process oils, aromatic process oils, and naphthenic process oils. Commercially available oils can be used, and examples of such commercially available oils include those from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Nisshin Oillio Group, Ltd., and others. These oils may be used individually or in combination of two or more types.

[0069] As the oil, a naphthenic oil containing asphalt is preferred. When the rubber composition contains a naphthenic oil containing asphalt, the cohesiveness of the rubber composition during mixing is further improved, and the workability of the rubber composition during mixing is further enhanced. As the naphthenic oil containing asphalt, it is preferable to obtain a mixture of naphthenic base oil and asphalt in a mass ratio in the range of (95 / 5) to (30 / 70). If the mass ratio is within this range, the compatibility between the rubber component (A) and the oil is further improved. As the naphthenic base oil, a hydrogenated naphthenic base oil is preferred, and a hydrogenated naphthenic base oil obtained by highly hydrogenating and refining aromatic oils or naphthenic oils using a high-pressure, high-temperature hydrogenation refining production apparatus is particularly preferred. Specifically, such hydrogenated naphthenic base oils are available as commercially available products such as SNH8, SNH46, SNH220, and SNH440 (all trademarks) manufactured by Sankyo Yuka Kogyo Co., Ltd. Furthermore, considering compatibility with the rubber components used and the effect of improving cohesion during the mixing of the rubber composition, it is preferable that the asphalt mixed with the naphthenic base oil contains 5% by mass or less of asphalt. The asphalt is quantified by compositional analysis measured in accordance with the JPI method [Japan Petroleum Society standard JPI-5S-22-83 (established in 1983), standard name "Compositional analysis method of asphalt by column chromatography"]. Such asphalt is preferably straight asphalt, and particularly preferably naphthenic straight asphalt. Furthermore, the kinematic viscosity of the asphalt at 120°C is 300 mmHg. ２ It is preferable that the pressure is less than or equal to one second. The method of mixing the asphalt is not particularly limited, but from the viewpoint of ease of preparation and economic efficiency, it is preferable to prepare the asphalt by dissolving it in a naphthenic base oil (including drawer oil and blending oil). As the naphthenic oil containing asphalt, it is preferable to use "A / O Mix," a product manufactured by Sankyo Yuka Kogyo Co., Ltd., which is obtained by mixing a hydrogenated naphthenic base oil produced by a high-pressure, high-temperature hydrogenation refining apparatus with naphthenic straight asphalt containing 5% or less asphaltene by mass, in a mass ratio of 63 / 37.

[0070] From the viewpoint of further improving the cohesiveness of the rubber composition during mixing and further improving workability during mixing, the oil content is preferably more than 0 parts by mass and 15 parts by mass or less per 100 parts by mass of the rubber component (A).

[0071] (Liquid softeners other than oil) The RFID tag coating rubber composition of this embodiment may contain liquid softeners other than the oil mentioned above. Here, "liquid softener" refers to a compounding agent that is liquid at 25°C (room temperature) and has the effect of softening the rubber composition. The liquid softener is not particularly limited and includes liquid polymers and the like.

[0072] As the liquid polymer, a liquid diene polymer is preferred. Examples of such liquid diene polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid polybutadiene (liquid BR), liquid polyisoprene (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer), liquid polyfarnesene, liquid farnesene-butadiene copolymer, and the like. These liquid polymers may be hydrogenated, or their ends or main chains may be modified with functional groups (polar groups). These liquid polymers may be used individually or in combination of two or more.

[0073] The content of liquid softeners other than the aforementioned oil is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the content of the liquid softener is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, preferably 100 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0074] (Tackifier) ​​The RFID tag coating rubber composition of this embodiment preferably contains a tackifier. When the rubber composition contains a tackifier, the tackiness of the rubber composition is improved, and the workability of the rubber composition during tire molding is improved. Various natural resins and synthetic resins can be used as the tackifier, and specifically, it is preferable to use rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, and xylene resins. These tackifiers may be used individually or in combination of two or more. When the rubber composition contains at least one selected from the group consisting of rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, and xylene resins, the tackiness of the rubber composition is further improved, and the workability of the rubber composition during tire molding is further improved. Among the resins, terpene resins and rosin resins are particularly preferred. Since terpene resins and rosin resins are naturally derived and sustainable resins, they can further reduce the environmental impact.

[0075] Examples of rosin-based resins include natural resin rosins such as gum rosin contained in raw pine resin and tall oil, tall oil rosin, and wood rosin. Examples of modified rosins, rosin derivatives, and modified rosin derivatives include polymerized rosin and its partially hydrogenated rosin; glycerol ester rosin and its partially hydrogenated or fully hydrogenated rosin; pentaerythritol ester rosin and its partially hydrogenated or polymerized rosin; and so on.

[0076] The aforementioned terpene resins are solid resins obtained by polymerizing turpentine oil, which is obtained simultaneously when rosin is obtained from pine trees, or polymer components separated therefrom, using a Friedel-Crafts type catalyst. Examples include β-pinene resin and α-pinene resin. Terpene resins also include terpene-aromatic compound resins, and typical examples of such terpene-aromatic compound resins include terpene-phenol resin and styrene-terpene resin. Terpene-phenol resins can be obtained by reacting terpenes with various phenols using a Friedel-Crafts type catalyst, or by further condensation with formalin. Styrene-terpene resins can be obtained by reacting styrene with terpenes using a Friedel-Crafts type catalyst. There are no particular restrictions on the terpenes used as raw materials, but monoterpene hydrocarbons such as α-pinene and limonene are preferred, those containing α-pinene are more preferred, and α-pinene is particularly preferred.

[0077] In the aforementioned synthetic resin, the petroleum-based resin is obtained, for example, by polymerizing the cracked oil fraction containing unsaturated hydrocarbons such as olefins and diolefins, which are produced as by-products along with petrochemical basic raw materials such as ethylene and propylene by the thermal decomposition of naphtha in the petrochemical industry, using a Friedel-Crafts type catalyst. The petroleum-based resin is obtained by the thermal decomposition of naphtha. ５ Aliphatic petroleum resin obtained by (co)polymerizing the fraction (hereinafter referred to as "C ５ It is sometimes called a "resin system," and is obtained by the thermal decomposition of naphtha. ９ Aromatic petroleum resin obtained by (co)polymerizing the fraction (hereinafter referred to as "C ９ It is sometimes called a "resin system," as mentioned above. ５ fractions and C ９ Copolymerized petroleum resin obtained by copolymerizing the fraction (hereinafter referred to as "C ５ -C ９ These are sometimes called "styrene resins." Examples include alicyclic compound petroleum resins such as hydrogenated resins and dicyclopentadiene resins, styrene resins such as styrene, substituted styrene, or copolymers of styrene and other monomers.

[0078] C obtained by the thermal decomposition of naphtha５ The fraction typically contains olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, as well as diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene. ９ Aromatic petroleum resins obtained by (co)polymerizing the fractions are resins polymerized with C9 aromatics, with vinyltoluene and indene as the main monomers, and are obtained by the thermal decomposition of naphtha. ９ Specific examples of fractions include styrene congeners such as α-methylstyrene, β-methylstyrene, and γ-methylstyrene, as well as indene congeners such as indene and coumarone. Trademarks include Petridine (Mitsui Petrochemical), Petrite (Mikuni Chemical), Neopolymer (Nippon Petrochemical), and Petol (Toyo Soda).

[0079] Furthermore, from the standpoint of workability, C ９ Modified petroleum resins, which are obtained by modifying petroleum resins consisting of fractions, can be suitably used. As the modified petroleum resin, C modified with an unsaturated alicyclic compound can be used. ９ C-type petroleum resin, modified with a compound having a hydroxyl group ９ C-type petroleum resin, modified with unsaturated carboxylic acid compounds ９ Examples include petroleum resins and the like.

[0080] Preferred unsaturated alicyclic compounds include cyclopentadiene and methylcyclopentadiene. Furthermore, as unsaturated alicyclic compounds, Diels-Alder reaction products of alkylcyclopentadiene are also preferred, and examples of such Diels-Alder reaction products of alkylcyclopentadiene include dicyclopentadiene, cyclopentadiene / methylcyclopentadiene codimers, and tricyclopentadiene. Among the aforementioned unsaturated alicyclic compounds, dicyclopentadiene is particularly preferred. Dicyclopentadiene-modified C ９ The petroleum resin is composed of dicyclopentadiene and C ９ It can be obtained by thermal polymerization or the like in the presence of both fractions. The dicyclopentadiene-modified C ９An example of a petroleum-based resin is Neopolymer 130S (manufactured by Nippon Petrochemical Co., Ltd.).

[0081] Furthermore, compounds having a hydroxyl group include alcohol compounds and phenol compounds. Specific examples of alcohol compounds include, for example, allyl alcohol and 2-butene-1,4-diol, which are alcohol compounds having a double bond. Phenolic compounds that can be used include alkylphenols such as phenol, cresol, xylenol, p-tert-butylphenol, p-octylphenol, and p-nonylphenol. These compounds having a hydroxyl group may be used individually or in combination of two or more. Also, C compounds having a hydroxyl group... ９ The petroleum resin can be produced by methods such as thermal polymerization of (meth)acrylate alkyl esters, etc., together with petroleum fractions to introduce ester groups into the petroleum resin, followed by reduction of the ester groups; or by methods in which double bonds remain or are introduced into the petroleum resin, followed by hydration of the double bonds. ９ As for the petroleum resin, those obtained by various methods as described above can be used, but from the standpoint of performance and manufacturing, it is preferable to use phenol-modified petroleum resin, etc. The phenol-modified petroleum resin is C ９ It is obtained by cationic polymerization of the fraction in the presence of phenol, is easily modified, and is inexpensive. The phenol-modified C ９ An example of a petroleum-based resin is Neopolymer E-130 (manufactured by Nippon Petrochemical Co., Ltd.).

[0082] Furthermore, C modified with the aforementioned unsaturated carboxylic acid compound ９ Petroleum resins are C ９ Petroleum resins can be modified with ethylenically unsaturated carboxylic acids. Typical examples of such ethylenically unsaturated carboxylic acids include (anhydride) maleic acid, fumaric acid, itaconic acid, tetrahydro(anhydride) phthalic acid, (meth)acrylic acid, or citraconic acid. Unsaturated carboxylic acid modification C ９ Petroleum resins are C ９ It can be obtained by thermal polymerization of a petroleum resin and an ethylene-based unsaturated carboxylic acid. In the present invention, maleic acid modified C ９Petroleum resins are preferred. Unsaturated carboxylic acid modified C ９ An example of a petroleum-based resin is Neopolymer 160 (manufactured by Nippon Petrochemical Co., Ltd.).

[0083] Furthermore, C obtained by the thermal decomposition of naphtha ５ fractions and C ９ The copolymer resin of the fraction can be suitably used. Here, C ９ There are no particular restrictions on the fraction, but C obtained by the thermal decomposition of naphtha is also acceptable. ９ It is preferable that it be a fraction. Specifically, examples include TS30, TS30-DL, TS35, TS35-DL, etc., from the Struktol series manufactured by Schill & Seilacher.

[0084] In the aforementioned synthetic resins, examples of phenolic resins include alkylphenol formaldehyde resins and their rosin-modified derivatives, alkylphenol acetylene resins, modified alkylphenol resins, terpene phenol resins, and more specifically, novolac-type alkylphenol resins such as Hitanol 1502 (manufactured by Hitachi Chemical Co., Ltd.) and p-tert-butylphenol acetylene resins such as Coresine (manufactured by BASF).

[0085] In the aforementioned synthetic resins, examples of coal-based resins include coumarone indene resin, and examples of xylene-based resins include xylene formaldehyde resin. In addition, polybutene can also be used as a resin with tackifying properties.

[0086] The resin may be hydrogenated, that is, it may be a hydrogenated resin. Furthermore, the resin may have functional groups that interact with fillers such as carbon black and silica introduced through modification. Examples of such functional groups include amino groups, amide groups, isocyanate groups, imino groups, imidazole groups, urea groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, ether groups, carbonyl groups, oxycarbonyl groups, silyl groups, alkoxysilyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, and thiocarbonyl groups.

[0087] The resin preferably has a softening point of 30°C or higher, more preferably 60°C or higher, more preferably 80°C or higher, more preferably higher than 110°C, more preferably 116°C or higher, more preferably 120°C or higher, more preferably 123°C or higher, and even more preferably 127°C or higher. Furthermore, from the viewpoint of processability, the resin preferably has a softening point of 160°C or lower, more preferably 150°C or lower, more preferably 145°C or lower, more preferably 141°C or lower, and even more preferably 136°C or lower. In this specification, the softening point of the tackifier (resin) is the temperature at which the sphere drops when the softening point specified in JIS K 6220-1:2015 (ISO 28641:2010) is measured using a ring-type softening point measuring device.

[0088] Commercially available tackifiers can be used, and examples of such commercially available tackifiers include products from ENEOS Corporation, Arakawa Chemical Industries, Ltd., ExxonMobil, Kraton Polymers, Yasuhara Chemical Co., Ltd., Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Corporation, Tosoh Corporation, Rutgers Chemicals, BASF, Kraton Polymers, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., Taoka Chemical Industries, Ltd., and others.

[0089] From the viewpoint of further improving the tackiness of the rubber composition and further improving workability during tire molding, the content of the tackifier is preferably more than 0 parts by mass and 15 parts by mass or less per 100 parts by mass of the rubber component (A).

[0090] (Carbon Black) The RFID tag coating rubber composition of this embodiment may or may not contain carbon black as a filler other than silica. Plant-derived carbon black and carbon black obtained by recycling (i.e., recycled carbon black) are particularly preferred as the carbon black. Examples of plant-derived carbon black include those derived from castor oil and pine resin oil. Examples of recycled carbon black include carbon black obtained by decomposing (especially by thermal decomposition) cross-linked rubber products such as used tires, and carbon black obtained from waste oil.

[0091] The cross-linked rubber products used in the aforementioned decomposition may be grouped by the type of rubber component they contain beforehand, and the decomposition process may be carried out for each group separately. Alternatively, they may be grouped by the type of filler they contain beforehand (for example, the type of carbon black, the type of silica, the mixing ratio of carbon black and silica, etc.), and the decomposition process may be carried out for each group separately. Furthermore, they may be grouped by both the type of rubber component and the type of filler, and the decomposition process may be carried out for each group separately. When the decomposition process is carried out for each group in this way, recycled carbon black with more uniform physical properties can be obtained, and when it is again incorporated into the rubber component, a rubber composition with better performance can be obtained.

[0092] Furthermore, if the cross-linked rubber product used in the decomposition is derived from a tire, it may be grouped in advance by tire type (for example, for passenger cars, trucks and buses, heavy vehicles such as off-road vehicles, aircraft, agricultural vehicles, etc.) and then the decomposition process may be carried out for each group. Alternatively, it may be grouped in advance by tire component (for example, tread rubber, sidewall rubber, bead rubber, steel cord coated rubber, organic fiber coated rubber, pad rubber, cushion rubber, etc.) and then the decomposition process may be carried out for each group. In addition, it may be possible to group by tire type and by tire component and then carry out the decomposition process for each group. When the decomposition process is carried out for each group in this way, recycled carbon black with more uniform physical properties can be obtained, and when it is again blended into the rubber component, a rubber composition with better performance can be obtained.

[0093] The grade of carbon black is not particularly limited, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. Commercially available carbon black can be used, and examples of commercially available carbon black include products from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Birla Carbon, etc. These carbon blacks may be used individually or in combination of two or more types.

[0094] The nitrogen adsorption specific surface area (N) of the carbon black ２ SA) is not particularly limited and can be adjusted as appropriate depending on the tire category, tire components, target performance, etc. For example, the specific surface area (N) of carbon black nitrogen adsorption. ２ SA) is 20m ２ Preferably 50 m ２ More preferably 70 m ２ More preferably 90 m ２ More preferably 200m ２ Preferably less than / g, and 150m ２More preferably less than / g, and 130m ２ A value of less than or equal to / g is even more preferable. In this specification, the specific surface area (N) of carbon black for nitrogen adsorption is defined as the specific surface area (N) of carbon black. ２ SA) is determined according to JIS K 6217-2:2017 (ISO 4652:2012).

[0095] The carbon black content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 0 parts by mass (i.e., no carbon black) per 100 parts by mass of the rubber component (A). When the carbon black content is 15 parts by mass or less per 100 parts by mass of the rubber component (A), the dielectric constant of the rubber composition decreases, and the communication distance of the RFID tag increases. Furthermore, when the carbon black content is 0 parts by mass (i.e., no carbon black), the dielectric constant of the rubber composition decreases further, and the communication distance of the RFID tag increases even further.

[0096] The content of silica (B) in the total content of silica (B) and carbon black is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass. When the content of silica (B) in the total content of silica (B) and carbon black is 80 to 100% by mass, the crack resistance and elastic modulus of the rubber composition can be improved while the dielectric constant of the rubber composition can be reduced, thereby further extending the communication range of the RFID tag.

[0097] (Rubber Powder) The RFID tag coating rubber composition of this embodiment may contain rubber powder. The rubber powder may be obtained by crushing used rubber products such as used tires, and optionally removing reinforcing materials such as steel materials and fibers, dust, glass, sand, stones, etc., or by preparing a new vulcanized rubber composition for the production of rubber powder and crushing it. For example, rubber powder can be obtained from vulcanized rubber by the method described in "Rubber Chemistry and Technology". In the process of crushing vulcanized rubber to obtain rubber powder, mechanical treatment or low-temperature treatment may be used. For example, in mechanical treatment, various crushing equipment such as cracker mills and granulators can be used to mechanically crush the vulcanized rubber into fine particles. In low-temperature treatment, the finely chopped vulcanized rubber is frozen at an extremely low temperature and then crushed into fine particles. In addition, a magnetic separator can be used to remove steel materials, and an air separator can be used to remove fibers. Commercially available rubber powders can be used, and examples of such commercially available rubber powders include those from Global Corporation or Nantong Huili Rubber Corporation. From the viewpoint of reducing environmental impact, it is preferable to use rubber powder obtained by crushing used rubber products such as used tires. The rubber powder may be used alone or in combination of two or more types.

[0098] The composition of the rubber powder is not particularly limited and depends on the composition of the vulcanized rubber used as a raw material, such as used rubber products (used tires). In one embodiment, the rubber powder includes rubber components, carbon black, silica, etc. The rubber components, carbon black, silica, etc. contained in the rubber powder may be the same as, or different from, the rubber components (A), carbon black, silica (B), etc. that may be included in the RFID tag coating rubber composition of this embodiment described above.

[0099] The rubber powder preferably has a volume-average particle diameter of 1000 μm or less, more preferably 500 μm or less, even more preferably 200 μm or less, and even more preferably 100 μm or less. Furthermore, the smaller the volume-average particle diameter of the rubber powder, the better, and there is no particular lower limit. In this specification, the volume-average particle diameter is measured using a laser diffraction particle size distribution analyzer, for example, the "CAPA500" manufactured by Horiba, Ltd.

[0100] The rubber powder preferably has a residue of less than 1% by mass after sieving through a 60-mesh sieve, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, with no particular lower limit. Furthermore, the rubber powder preferably has a residue of less than 10% by mass after sieving through an 80-mesh sieve, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, with no particular lower limit. In this specification, the sieve residue is measured according to ASTM D5644-01.

[0101] The rubber powder preferably has an acetone extract content of 12% by mass or less, more preferably 11% by mass or less, even more preferably 10% by mass or less, and preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more. In this specification, the acetone extract content in the rubber powder refers to the acetone extract content (%) obtained by an acetone extraction method in accordance with JIS K6350.

[0102] The content of the rubber powder is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the content of the rubber powder is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and also preferably 200 parts by mass or less, more preferably 150 parts by mass or less, more preferably 100 parts by mass or less, more preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0103] (Anti-aging agent) The RFID tag coating rubber composition of this embodiment may contain an anti-aging agent. Examples of the anti-aging agent include 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'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), and 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline. Commercially available products can be used as the aforementioned anti-aging agents. Examples of commercially available anti-aging agents include those from Ouchi Shinko Chemical Industry Co., Ltd., Sumitomo Chemical Co., Ltd., Seiko Chemical Corporation, and Flexis Co., Ltd. These anti-aging agents may be used individually or in combination of two or more types.

[0104] The content of the anti-aging agent is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the content of the anti-aging agent is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, even more preferably 2 parts by mass or more, and preferably 12 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0105] (Wax) The RFID tag coating rubber composition of this embodiment may contain wax. Examples of the wax include natural waxes such as plant-based waxes and animal-based waxes; petroleum-based waxes such as paraffin wax and microcrystalline wax; and synthetic waxes such as polymers of ethylene and polymers of propylene. Commercially available waxes can be used, and examples of commercially available waxes include those from Seiko Chemical Co., Ltd., Nippon Seiro Co., Ltd., and Ouchi Shinko Chemical Industry Co., Ltd. These waxes may be used individually or in combination of two or more types.

[0106] The amount of wax is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the amount of wax is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0107] (Stearic Acid) The RFID tag coating rubber composition of this embodiment may contain stearic acid. Commercially available stearic acid can be used, and examples of commercially available stearic acid include products from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries Ltd., Chiba Fatty Acid Co., Ltd., etc. These commercially available stearic acid products may be used individually or in combination of two or more types.

[0108] The stearic acid content is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the stearic acid content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0109] (Zinc Oxide) The RFID tag coating rubber composition of this embodiment may contain zinc oxide (zinc oxide). Preferably, the zinc oxide is obtained not only from zinc ingots but also from recycled zinc or zinc dross (i.e., obtained through recycling). Commercially available zinc oxide can be used, and examples of commercially available zinc oxide include products from Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., etc. These commercially available zinc oxide products may be used individually or in combination of two or more types.

[0110] The zinc oxide content is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, the zinc oxide content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0111] (Other) In addition to the components described above, the RFID tag coating rubber composition of this embodiment may further contain various additives commonly used in the tire industry, such as fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica; organic peroxides; etc. The content of these additives is not particularly limited and can be adjusted as appropriate depending on the tire category to which it is applied, the target performance, etc. For example, a range of 0.1 to 200 parts by mass per 100 parts by mass of the rubber component (A) is preferred.

[0112] (Method for manufacturing the rubber composition) The method for manufacturing the RFID tag coating rubber composition of this embodiment is not particularly limited, but for example, it can be manufactured by mixing the rubber component (A) with plant-derived silica (B1) and various components selected as needed, then kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized by vulcanization.

[0113] There are no particular restrictions on the mixing conditions, and various conditions such as the input volume of the mixing device, the rotation speed of the rotor, the ram pressure, as well as the mixing temperature, mixing time, and the type of mixing device can be appropriately selected according to the purpose. Examples of mixing devices include Banbury mixers, intermixes, kneaders, and rolls, which are commonly used for mixing rubber compositions.

[0114] There are no particular restrictions on the heat treatment conditions, and various conditions such as heat treatment temperature, heat treatment time, and heat treatment equipment can be appropriately selected according to the purpose. Examples of such heat treatment equipment include heat treatment roll machines commonly used for heat treatment of rubber compositions.

[0115] There are no particular restrictions on the extrusion conditions, and various conditions such as extrusion time, extrusion speed, extrusion equipment, and extrusion temperature can be appropriately selected according to the purpose. Examples of extrusion equipment include extruders typically used for extruding rubber compositions. The extrusion temperature can be determined as appropriate.

[0116] There are no particular restrictions on the apparatus, method, and conditions for performing the vulcanization, and they can be appropriately selected according to the purpose. Examples of vulcanization apparatus include molding vulcanizers that use molds for vulcanizing rubber compositions. As for the vulcanization conditions, the temperature is, for example, around 100 to 190°C.

[0117] <Tire> The tire of this embodiment is characterized by having an RFID tag coated with the above-described RFID tag coating rubber composition. Because the tire of this embodiment has an RFID tag coated with the above-described RFID tag coating rubber composition, the proportion of sustainable materials is improved and communication performance is not impaired.

[0118] The aforementioned RFID tags are generally made of materials such as metal and resin. For example, in one embodiment, the RFID tag comprises an electronic component and an antenna component connected to the electronic component, where the housing (or package) of the electronic component is made of resin and the antenna component is made of metal. When coating the RFID tag with the RFID tag coating rubber composition of this embodiment described above, sufficient adhesion between the RFID tag and the coating rubber can be ensured by applying an adhesive such as "ChemLock" (registered trademark) manufactured by Rhode Corporation to the RFID tag in advance.

[0119] Furthermore, since the RFID tag is harder than the rubber components in the tire, it is preferable that the coating rubber of the RFID tag has a higher modulus of elasticity (i.e., is harder) than adjacent rubber components (for example, the side rubber and stiffener described later) in order to suppress stress concentration on the RFID tag. The above-mentioned RFID tag coating rubber composition has a high modulus of elasticity and is hard, and therefore also has the effect of suppressing stress concentration on the RFID tag.

[0120] It is preferable to place the RFID tag in a part of the tire where there is relatively little distortion during driving. In one embodiment, it is preferable to place the RFID tag coated with the above-mentioned RFID tag coating rubber composition between a stiffener located on the radially outer side of the bead core embedded in the bead portion of the tire, and the side rubber located on the tire widthwise outer side of the carcass of the tire side. Furthermore, in this embodiment, it is even more preferable to place the RFID tag coated with the RFID tag coating rubber composition in a part located radially inward from the maximum width portion of the tire.

[0121] Figure 1 is a cross-sectional view of one embodiment of the tire of the present invention. The tire 1 shown in Figure 1 has a pair of bead portions 2 and a pair of side portions 3, and a tread portion 4 connected to both side portions 3, and comprises a carcass 5 that extends in a toroidal shape between the pair of bead portions 2 and reinforces these portions 2, 3, and 4, a belt 6 arranged on the radially outer side of the crown portion of the carcass 5, and stiffeners 8 arranged on the radially outer side of the ring-shaped bead cores 7 that are embedded in the bead portions 2. The stiffeners 8 consist of a relatively rigid hard stiffener 8a adjacent to the radially outer side of the bead core 7, and a relatively rigid soft stiffener 8b adjacent to the radially outer side of the hard stiffener 8a. In addition, side rubber 9 is arranged on the tire widthwise outer side of the carcass 5 of the side portion 3.

[0122] In the illustrated example tire 1, the carcass 5 has a main body portion 5a that extends toroidally between a pair of bead cores 7, and folded portions 5b that are wound radially outward from the inside to the outside in the tire width direction around each bead core 7. Note that the structure and number of plies of the carcass 5 are not limited to this. The stiffener 8 is positioned between the main body portion 5a of the carcass 5 and its folded portions 5b. A wire chafer 10 is also provided on the outer surface side of the folded portions 5b of the carcass 5, and the wire chafer 10 further extends along the outside in the tire width direction of the stiffener 8.

[0123] Furthermore, an RFID tag 12 coated with coating rubber 11 is positioned radially inward from the tire's widest point, between the side rubber 9 and the soft stiffener 8b, and on the radially outward side of the wire chafer 10. Here, the coating rubber 11 uses the RFID tag coating rubber composition described above. The RFID tag 12 coated with coating rubber 11 (RFID tag-rubber composite) can be manufactured, for example, by preparing two rubber sheets made of the RFID tag coating rubber composition described above and sandwiching the RFID tag 12 between the rubber sheets. The RFID tag-rubber composite can be laminated together with other rubber members to form a green tire, and the green tire can be vulcanized to produce the tire of this embodiment.

[0124] As described above, the rubber composition applied to the coating rubber 11 has an improved proportion of sustainable materials, and therefore the tire 1 shown in Figure 1 has an improved proportion of sustainable materials. Furthermore, as described above, the rubber composition applied to the coating rubber 11 has good communication performance, and therefore the tire 1 shown in Figure 1 has a long communication range and excellent communication performance. Moreover, as described above, the rubber composition applied to the coating rubber 11 has a good balance of crack resistance, adhesion to adjacent rubber members, and elastic modulus, and therefore the tire 1 shown in Figure 1 has excellent durability.

[0125] The tire of this embodiment can be manufactured by conventional methods using the rubber composition described above. For example, depending on the type of tire to be applied, the tire of this embodiment may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, or by molding a semi-vulcanized rubber that has undergone a pre-vulcanization process and then performing full vulcanization. The tire of this embodiment is preferably a pneumatic tire, and as the gas used to fill the pneumatic tire, in addition to ordinary air or air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used.

[0126] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0127] <Preparation of the Rubber Composition of Comparative Example 1> Following the formulation shown in Table 1, the compounding components, excluding the vulcanization accelerator, vulcanizing agent, and other Pro chemicals, were filled into a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to a filling rate of 55% to 65%, and the mixture was kneaded at a rotation speed of 80 rpm until it reached 160°C or after 4 minutes. Next, the vulcanization accelerator, vulcanizing agent, and other Pro chemicals were added to the mixture in the amounts shown in Table 1, and the mixture was kneaded at 80°C for 2 minutes using an open roll to obtain an unvulcanized rubber composition. The total mass ratio of materials derived from biological resources (biomass resources) and materials derived from recycled resources (recycled resources) was calculated for this rubber composition to determine the sustainable material ratio.

[0128] <Preparation of the rubber composition of Example 1> According to the formulation shown in Table 1, the formulation components, excluding the vulcanization accelerator, vulcanizing agent, and other Pro chemicals, were filled into a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to a filling rate of 55% to 65%, and the mixture was kneaded at a rotation speed of 80 rpm until it reached 160°C or 4 minutes had elapsed. Next, the vulcanization accelerator, vulcanizing agent, and other Pro chemicals were added to the mixture in the amounts shown in Table 1, and the mixture was kneaded at 80°C for 2 minutes using an open roll to obtain an unvulcanized rubber composition. The total mass ratio of materials derived from biological resources (biomass resources) and materials derived from recycled resources (recycled resources) was calculated for the rubber composition to determine the sustainable material ratio.

[0129]

[0130] *1 Natural rubber: RSS#3 *2 Mineral-derived silica: Manufactured by Tosoh Silica Co., Ltd., product name "NipSeal AQ" *3 Plant-derived silica: Rice husk silica *4 Silane coupling agent: Bis(3-triethoxylylpropyl) disulfide (average sulfur chain length: 2.35), silane coupling agent manufactured by Evonik, product name "Si75" *5 Tackifier: Manufactured by SI Group RIBECOURT S.A.S., product name "R7510PJ" *6 Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazolyl sulfenamide, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Noxellar CZ-G" *7 Insoluble sulfur: Sulfur containing insoluble sulfur, manufactured by Sanshin Chemical Industry Co., Ltd., product name "Sanfer Ex", percentage of insoluble sulfur in sulfur = 90% by mass

[0131] Table 1 shows that the rubber composition of the embodiment according to the present invention has an improved proportion of sustainable materials, and that applying it to tires can improve the proportion of sustainable materials in the tires.

[0132] 1: Tire 2: Bead section 3: Side section 4: Tread section 5: Carcass 5a: Main body of the carcass 5b: Folded section of the carcass 6: Belt 7: Bead core 8: Stiffener 8a: Hard stiffener 8b: Soft stiffener 9: Side rubber 10: Wire chafer 11: Coating rubber 12: RFID tag

Claims

1. A coating rubber composition for RFID tags, comprising a rubber component (A) and silica (B), wherein the silica (B) includes plant-derived silica (B1), and the silica (B) content is 45 parts by mass or more per 100 parts by mass of the rubber component (A).

2. The RFID tag coating rubber composition according to claim 1, further comprising a silane coupling agent (C).

3. The RFID tag coating rubber composition according to claim 2, wherein the content of the silane coupling agent (C) is 5 to 20% by mass of the content of the silica (B).

4. The RFID tag coating rubber composition according to claim 1, wherein the silica (B) content is 45 to 90 parts by mass per 100 parts by mass of the rubber component (A).

5. The RFID tag coating rubber composition according to claim 1, wherein the plant-derived silica (B1) is silica derived from a grass plant.

6. The RFID tag coating rubber composition according to claim 5, wherein the plant-derived silica (B1) is silica derived from rice husks.

7. The RFID tag coating rubber composition according to claim 1, wherein the carbon black content is 15 parts by mass or less per 100 parts by mass of the rubber component (A).

8. The RFID tag coating rubber composition according to claim 1, wherein the content ratio of silica (B) in the total content of silica (B) and carbon black is 80 to 100% by mass.

9. A tire characterized by comprising an RFID tag coated with the RFID tag coating rubber composition described in claim 1.

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